Tag Archives: stem cells

Protocols for mouse-human chimeric embryos

This work on a type of species boundary-crossing could be very disturbing for some folks. That said, here’s more about the science from a July 2, 2021 news item on phys.org,

A year after University at Buffalo [in New York state] scientists demonstrated that it was possible to produce millions of mature human cells in a mouse embryo, they have published a detailed description of the method so that other laboratories can do it, too.

A July 2, 2021 University at Buffalo (UB) news release (also on EurekAlert) by Ellen Goldbaum, which originated the news item, explains why scientists have created these chimeras,

The ability to produce millions of mature human cells in a living organism, called a chimera, which contains the cells of two species, is critical if the ultimate promise of stem cells to treat or cure human disease is to be realized. But to produce those mature cells, human primed stem cells must be converted back into an earlier, less developed naive state so that the human stem cells can co-develop with the inner cell mass in a mouse blastocyst.

The protocol outlining how to do that has now been published in Nature Protocols by the UB scientists. They were invited to publish it because of the significant interest generated by the team’s initial publication describing their breakthrough last May [2020].

“This paper will enable many scientists to use this new platform to study the human disease of their interest,” said Jian Feng, PhD, professor of physiology and biophysics in the Jacobs School of Medicine and Biomedical Sciences at UB and senior author. “Over time, it will transform biomedical research toward a more effective use of the human model system to directly study virtually any inborn condition of an individual. It will stimulate unforeseen discoveries and applications that may fundamentally change our understanding of human biology and medicine.”

The protocol will allow scientists to create animal models that Feng said provide a much more realistic picture of embryonic development than has ever been possible. These more realistic animal models also will have the potential to reveal the mechaniswms behind numerous diseases, especially those that afflict individuals from birth.

Better mouse models

“This step-by-step protocol will benefit the entire field by enabling other scientists to use our methods to generate chimeras to study human diseases that they are experts in,” said Feng. “It will lead to the generation of better mouse models for various human diseases, such as sickle cell anemia, COVID-19 and many others, or various human developmental disorders.” The paper demonstrates how to generate naive human pluripotent stem cells from existing induced pluripotent stem cells that may be derived from patients with various diseases, how to generate mouse-human chimeras using these cells and how to quantify the amount of human cells in the chimeras.

“Using our method, one can now track the development of naive human pluripotent stem cells in mouse-human chimeric embryos in real-time,” said Feng. These stem cells can then be manipulated either genetically or pharmacologically, providing valuable information about human development and disease.

“For example, one can label naive human pluripotent stem cells by inserting green fluorescent protein in a hemoglobin gene to study the development of human red blood cells in mouse-human chimeras,” said Feng.

Another application is to generate humanized mouse models to study many human diseases.

“These mice contain critical human cells, tissues or even organs so that they more accurately reflect the human condition,” said Feng. “With our method, the human cells are made along with the mouse during the development of the mouse embryo. There would be better matching and no rejections, because there are ways for the human cells to be made where there is no competition from their mouse counterparts.”

Organs for transplant in the future

By allowing others to improve and adapt the method to eventually generate chimeras in larger animals, this protocol may also lead to the generation of human organs to address the dire shortage of organs available for transplant, said Feng.

“If naive human pluripotent stem cells are able to generate significant amounts of mature human cells in other larger species, it could be possible to make human tissues or even human organs in chimeric animals,” Feng explained.

This would be possible using blastocyst complementation where, Feng explained, normal pluripotent stem cells from one species can reconstitute an organ for that species in a blastocyst of another species that been genetically modified not to grow that particular organ.

Feng added: “Ultimately, a better understanding of how human cells develop and grow in chimeras may enable the generation of human cells, tissues and organs in a completely artificial system and fundamentally change how we treat many human diseases. Research using chimeras is a bridge that must be crossed to reach that possibility.”

Here’s a link to and a citation for the 2021 article,

Generation of mouse–human chimeric embryos by Boyang Zhang, Hanqin Li, Zhixing Hu, Houbo Jiang, Aimee B. Stablewski, Brandon J. Marzullo, Donald A. Yergeau & Jian Feng. Nature Protocols (2021) DOI: https://doi.org/10.1038/s41596-021-00565-7 Published 02 July 2021

This article is behind a paywall.

Here’s a link to and citation for the 2020 work, which led to the publication of the protocols,

Transient inhibition of mTOR in human pluripotent stem cells enables robust formation of mouse-human chimeric embryos by Zhixing Hu, Hanqin Li, Houbo Jiang, Yong Ren, Xinyang Yu, Jingxin Qiu, Aimee B. Stablewski, Boyang Zhang, Michael J. Buck, Jian Feng. Science Advances 13 May 2020: Vol. 6, no. 20, eaaz0298 DOI: 10.1126/sciadv.aaz0298

This paper is open access.

Cortical spheroids (like mini-brains) could unlock (larger) brain’s mysteries

A March 19, 2021 Northwestern University news release on EurekAlert announces the creation of a device designed to monitor brain organoids (for anyone unfamiliar with brain organoids there’s more information after the news),

A team of scientists, led by researchers at Northwestern University, Shirley Ryan AbilityLab and the University of Illinois at Chicago (UIC), has developed novel technology promising to increase understanding of how brains develop, and offer answers on repairing brains in the wake of neurotrauma and neurodegenerative diseases.

Their research is the first to combine the most sophisticated 3-D bioelectronic systems with highly advanced 3-D human neural cultures. The goal is to enable precise studies of how human brain circuits develop and repair themselves in vitro. The study is the cover story for the March 19 [March 17, 2021 according to the citation] issue of Science Advances.

The cortical spheroids used in the study, akin to “mini-brains,” were derived from human-induced pluripotent stem cells. Leveraging a 3-D neural interface system that the team developed, scientists were able to create a “mini laboratory in a dish” specifically tailored to study the mini-brains and collect different types of data simultaneously. Scientists incorporated electrodes to record electrical activity. They added tiny heating elements to either keep the brain cultures warm or, in some cases, intentionally overheated the cultures to stress them. They also incorporated tiny probes — such as oxygen sensors and small LED lights — to perform optogenetic experiments. For instance, they introduced genes into the cells that allowed them to control the neural activity using different-colored light pulses.

This platform then enabled scientists to perform complex studies of human tissue without directly involving humans or performing invasive testing. In theory, any person could donate a limited number of their cells (e.g., blood sample, skin biopsy). Scientists can then reprogram these cells to produce a tiny brain spheroid that shares the person’s genetic identity. The authors believe that, by combining this technology with a personalized medicine approach using human stem cell-derived brain cultures, they will be able to glean insights faster and generate better, novel interventions.

“The advances spurred by this research will offer a new frontier in the way we study and understand the brain,” said Shirley Ryan AbilityLab’s Dr. Colin Franz, co-lead author on the paper who led the testing of the cortical spheroids. “Now that the 3-D platform has been developed and validated, we will be able to perform more targeted studies on our patients recovering from neurological injury or battling a neurodegenerative disease.”

Yoonseok Park, postdoctoral fellow at Northwestern University and co-lead author, added, “This is just the beginning of an entirely new class of miniaturized, 3-D bioelectronic systems that we can construct to expand the capacity of the regenerative medicine field. For example, our next generation of device will support the formation of even more complex neural circuits from brain to muscle, and increasingly dynamic tissues like a beating heart.”

Current electrode arrays for tissue cultures are 2-D, flat and unable to match the complex structural designs found throughout nature, such as those found in the human brain. Moreover, even when a system is 3-D, it is extremely challenging to incorporate more than one type of material into a small 3-D structure. With this advance, however, an entire class of 3-D bioelectronics devices has been tailored for the field of regenerative medicine.

“Now, with our small, soft 3-D electronics, the capacity to build devices that mimic the complex biological shapes found in the human body is finally possible, providing a much more holistic understanding of a culture,” said Northwestern’s John Rogers, who led the technology development using technology similar to that found in phones and computers. “We no longer have to compromise function to achieve the optimal form for interfacing with our biology.”

As a next step, scientists will use the devices to better understand neurological disease, test drugs and therapies that have clinical potential, and compare different patient-derived cell models. This understanding will then enable a better grasp of individual differences that may account for the wide variation of outcomes seen in neurological rehabilitation.

“As scientists, our goal is to make laboratory research as clinically relevant as possible,” said Kristen Cotton, research assistant in Dr. Franz’s lab. “This 3-D platform opens the door to new experiments, discovery and scientific advances in regenerative neurorehabilitation medicine that have never been possible.”

Caption: Three dimensional multifunctional neural interfaces for cortical spheroids and engineered assembloids Credit: Northwestern University

As for what brain ogranoids might be, Carl Zimmer in an Aug. 29, 2019 article for the New York Times provides an explanation,

Organoids Are Not Brains. How Are They Making Brain Waves?

Two hundred and fifty miles over Alysson Muotri’s head, a thousand tiny spheres of brain cells were sailing through space.

The clusters, called brain organoids, had been grown a few weeks earlier in the biologist’s lab here at the University of California, San Diego. He and his colleagues altered human skin cells into stem cells, then coaxed them to develop as brain cells do in an embryo.

The organoids grew into balls about the size of a pinhead, each containing hundreds of thousands of cells in a variety of types, each type producing the same chemicals and electrical signals as those cells do in our own brains.

In July, NASA packed the organoids aboard a rocket and sent them to the International Space Station to see how they develop in zero gravity.

Now the organoids were stowed inside a metal box, fed by bags of nutritious broth. “I think they are replicating like crazy at this stage, and so we’re going to have bigger organoids,” Dr. Muotri said in a recent interview in his office overlooking the Pacific.

What, exactly, are they growing into? That’s a question that has scientists and philosophers alike scratching their heads.

On Thursday, Dr. Muotri and his colleagues reported that they  have recorded simple brain waves in these organoids. In mature human brains, such waves are produced by widespread networks of neurons firing in synchrony. Particular wave patterns are linked to particular forms of brain activity, like retrieving memories and dreaming.

As the organoids mature, the researchers also found, the waves change in ways that resemble the changes in the developing brains of premature babies.

“It’s pretty amazing,” said Giorgia Quadrato, a neurobiologist at the University of Southern California who was not involved in the new study. “No one really knew if that was possible.”

But Dr. Quadrato stressed it was important not to read too much into the parallels. What she, Dr. Muotri and other brain organoid experts build are clusters of replicating brain cells, not actual brains.

If you have the time, I recommend reading Zimmer’s article in its entirety. Perhaps not coincidentally, Zimmer has an excerpt titled “Lab-Grown Brain Organoids Aren’t Alive. But They’re Not Not Alive, Either.” published in Slate.com,

From Life’s Edge: The Search For What It Means To Be Alive by Carl Zimmer, published by Dutton, an imprint of Penguin Publishing Group, a division of Penguin Random House, LLC. Copyright © 2021 by Carl Zimmer.

Cleber Trujillo led me to a windowless room banked with refrigerators, incubators, and microscopes. He extended his blue-gloved hands to either side and nearly touched the walls. “This is where we spend half our day,” he said.

In that room Trujillo and a team of graduate students raised a special kind of life. He opened an incubator and picked out a clear plastic box. Raising it above his head, he had me look up at it through its base. Inside the box were six circular wells, each the width of a cookie and filled with what looked like watered-down grape juice. In each well 100 pale globes floated, each the size of a housefly head.

Getting back to the research about monitoring brain organoids, here’s a link to and a citation for the paper about cortical spheroids,

Three-dimensional, multifunctional neural interfaces for cortical spheroids and engineered assembloids by Yoonseok Park, Colin K. Franz, Hanjun Ryu, Haiwen Luan, Kristen Y. Cotton, Jong Uk Kim, Ted S. Chung, Shiwei Zhao, Abraham Vazquez-Guardado, Da Som Yang, Kan Li, Raudel Avila, Jack K. Phillips, Maria J. Quezada, Hokyung Jang, Sung Soo Kwak, Sang Min Won, Kyeongha Kwon, Hyoyoung Jeong, Amay J. Bandodkar, Mengdi Han, Hangbo Zhao, Gabrielle R. Osher, Heling Wang, KunHyuck Lee, Yihui Zhang, Yonggang Huang, John D. Finan and John A. Rogers. Science Advances 17 Mar 2021: Vol. 7, no. 12, eabf9153 DOI: 10.1126/sciadv.abf9153

This paper appears to be open access.

According to a March 22, 2021 posting on the Shirley Riley AbilityLab website, the paper is featured on the front cover of Science Advances (vol. 7 no. 12).

First 3D heart printed using patient’s biological materials

This is very exciting news and it’s likely be at least 10 years before this technology could be made available to the public.

Caption: A 3D-printed, small-scaled human heart engineered from the patient’s own materials and cells. Credit: Advanced Science. © 2019 The Authors.

An April 15, 2019 news item on ScienceDaily makes a remarkable announcement,

In a major medical breakthrough, Tel Aviv University researchers have “printed” the world’s first 3D vascularised engineered heart using a patient’s own cells and biological materials. Their findings were published on April 15 [2019] in a study in Advanced Science.

Until now, scientists in regenerative medicine — a field positioned at the crossroads of biology and technology — have been successful in printing only simple tissues without blood vessels.

“This is the first time anyone anywhere has successfully engineered and printed an entire heart replete with cells, blood vessels, ventricles and chambers,” says Prof. Tal Dvir of TAU’s School of Molecular Cell Biology and Biotechnology, Department of Materials Science and Engineering, Center for Nanoscience and Nanotechnology and Sagol Center for Regenerative Biotechnology, who led the research for the study.

An April 15, 2019 Amricna Friends of Tel Aviv University (TAU) news release (also on EurekAlert), which originated the news item, provides more detail,

Heart disease is the leading cause of death among both men and women in the United States. Heart transplantation is currently the only treatment available to patients with end-stage heart failure. Given the dire shortage of heart donors, the need to develop new approaches to regenerate the diseased heart is urgent.

“This heart is made from human cells and patient-specific biological materials. In our process these materials serve as the bioinks, substances made of sugars and proteins that can be used for 3D printing of complex tissue models,” Prof. Dvir says. “People have managed to 3D-print the structure of a heart in the past, but not with cells or with blood vessels. Our results demonstrate the potential of our approach for engineering personalized tissue and organ replacement in the future.

Research for the study was conducted jointly by Prof. Dvir, Dr. Assaf Shapira of TAU’s Faculty of Life Sciences and Nadav Moor, a doctoral student in Prof. Dvir’s lab.

“At this stage, our 3D heart is small, the size of a rabbit’s heart, [emphasis mine] ” explains Prof. Dvir. “But larger human hearts require the same technology.”

For the research, a biopsy of fatty tissue was taken from patients. The cellular and a-cellular materials of the tissue were then separated. While the cells were reprogrammed to become pluripotent stem cells, the extracellular matrix (ECM), a three-dimensional network of extracellular macromolecules such as collagen and glycoproteins, were processed into a personalized hydrogel that served as the printing “ink.”

After being mixed with the hydrogel, the cells were efficiently differentiated to cardiac or endothelial cells to create patient-specific, immune-compatible cardiac patches with blood vessels and, subsequently, an entire heart.

According to Prof. Dvir, the use of “native” patient-specific materials is crucial to successfully engineering tissues and organs.

“The biocompatibility of engineered materials is crucial to eliminating the risk of implant rejection, which jeopardizes the success of such treatments,” Prof. Dvir says. “Ideally, the biomaterial should possess the same biochemical, mechanical and topographical properties of the patient’s own tissues. Here, we can report a simple approach to 3D-printed thick, vascularized and perfusable cardiac tissues that completely match the immunological, cellular, biochemical and anatomical properties of the patient.”

The researchers are now planning on culturing the printed hearts in the lab and “teaching them to behave” like hearts, Prof. Dvir says. They then plan to transplant the 3D-printed heart in animal models.

“We need to develop the printed heart further,” he concludes. “The cells need to form a pumping ability; they can currently contract, but we need them to work together. Our hope is that we will succeed and prove our method’s efficacy and usefulness.

“Maybe, in ten years, there will be organ printers in the finest hospitals around the world, and these procedures will be conducted routinely.”

Growing the heart to human size and getting the cells to work together so the heart will pump makes it seem like the 10 years Dvir imagines as the future date when there will be organ printers in hospitals routinely printing up hearts seems a bit optimistic. Regardless, I hope he’s right. Bravo to these Israeli researchers!

Here’s a link to and a citation for the paper,

3D Printing of Personalized Thick and Perfusable Cardiac Patches and Hearts by Nadav Noor, Assaf Shapira, Reuven Edri, Idan Gal, Lior Wertheim, Tal Dvir. Advanced Science DOI: https://doi.org/10.1002/advs.201900344 First published: 15 April 2019

This paper is open access.

Cyborg organoids?

Every time I think I’ve become inured to the idea of a fuzzy boundary between life and nonlife something new crosses my path such as integrating nanoelectronics with cells for cyborg organoids. An August 9, 2019 news item on ScienceDaily makes the announcement,

What happens in the early days of organ development? How do a small group of cells organize to become a heart, a brain, or a kidney? This critical period of development has long remained the black box of developmental biology, in part because no sensor was small or flexible enough to observe this process without damaging the cells.

Now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have grown simplified organs known as organoids with fully integrated sensors. These so-called cyborg organoids offer a rare glimpse into the early stages of organ development.

An August 8, 2019 Harvard John A. Paulson School of Engineering and Applied Sciences news release (also on EurekAlert but published August 9, 2019) by Leah Burrows, which originated the news item, expands on the theme,

“I was so inspired by the natural organ development process in high school, in which 3D organs start from few cells in 2D structures. I think if we can develop nanoelectronics that are so flexible, stretchable, and soft that they can grow together with developing tissue through their natural development process, the embedded sensors can measure the entire activity of this developmental process,” said Jia Liu, Assistant Professor of Bioengineering at SEAS and senior author of the study. “The end result is a piece of tissue with a nanoscale device completely distributed and integrated across the entire three-dimensional volume of the tissue.”

This type of device emerges from the work that Liu began as a graduate student in the lab of Charles M. Lieber, the Joshua and Beth Friedman University Professor. In Lieber’s lab, Liu once developed flexible, mesh-like nanoelectronics that could be injected in specific regions of tissue.

Building on that design, Liu and his team increased the stretchability of the nanoelectronics by changing the shape of the mesh from straight lines to serpentine structures (similar structures are used in wearable electronics). Then, the team transferred the mesh nanoelectronics onto a 2D sheet of stem cells, where the cells covered and interwove with the nanoelectronics via cell-cell attraction forces. As the stem cells began to morph into a 3D structure, the nanoelectronics seamlessly reconfigured themselves along with the cells, resulting in fully-grown 3D organoids with embedded sensors.

The stem cells were then differentiated into cardiomyocytes — heart cells — and the researchers were able to monitor and record the electrophysiological activity for 90 days.

“This method allows us to continuously monitor the developmental process and understand how the dynamics of individual cells start to interact and synchronize during the entire developmental process,” said Liu. “It could be used to turn any organoid into cyborg organoids, including brain and pancreas organoids.”

In addition to helping answer fundamental questions about biology, cyborg organoids could be used to test and monitor patient-specific drug treatments and potentially used for transplantations.

Here’s a link to and a citation for the paper

Cyborg Organoids: Implantation of Nanoelectronics via Organogenesis for Tissue-Wide Electrophysiology by Qiang Li, Kewang Nan, Paul Le Floch, Zuwan Lin, Hao Sheng, Thomas S. Blum, Jia Liu. Nano Lett.20191985781-5789 DOI: https://doi.org/10.1021/acs.nanolett.9b02512 Publication Date:July 26, 2019 Copyright © 2019 American Chemical Society

This paper is behind a paywall.

Cooking up a lung one way or the other

I have two stories about lungs and they are entirely different with the older one being a bioengineering story from the US and the more recent one being an artificial tissue story from the University of Toronto and the University of Ottawa (both in Canada).

Lab grown lungs

The Canadian Broadcasting Corporation’s Quirks and Quarks radio programme posted a December 29, 2018 news item (with embedded radio files) about bioengineered lunjgs,

There are two major components to building an organ: the structure and the right cells on that structure. A team led by Dr. Joan Nichols, a Professor of Internal Medicine, Microbiology and Immunology at the University of Texas Medical Branch in Galveston, were able to tackle both parts of the problem

In their experiment they used a donor organ for the structure. They took a lung from an unrelated pig, and stripped it of its cells, leaving a scaffold of collagen, a tough, flexible protein.  This provided a pre-made appropriate structure, though in future they think it may be possible to use 3-D printing technology to get the same result.

They then added cultured cells from the animal who would be receiving the transplant – so the lung was made of the animal’s own cells. Cultured lung and blood vessel cells were placed on the scaffold and it was  placed in a tank for 30 days with a cocktail of nutrients to help the cells stick to the scaffold and proliferate. The result was a kind of baby lung.

They then transplanted the bio-engineered, though immature, lung into the recipient animal where they hoped it would continue to develop and mature – growing to become a healthy, functioning organ.

The recipients of the bio-engineered lungs were four pigs adult pigs, which appeared to tolerate the transplants well. In order to study the development of the bio-engineered lungs, they euthanized the animals at different times: 10 hours, two weeks, one month and two months after transplantation.

They found that as early as two weeks, the bio-engineered lung had integrated into the recipient animals’ body, building a strong network of blood vessels essential for the lung to survive. There was no evidence of pulmonary edema, the build of fluid in the lungs, which is usually a sign of the blood vessels not working efficiently.  There was no sign of rejection of the transplanted organs, and the pigs were healthy up to the point where they were euthanized.

One lingering concern is how well the bio-engineered lungs delivered oxygen. The four pigs who received the trasplant [sic] had one original functioning lung, so they didn’t depend on their new bio-engineered lung for breathing. The scientists were not sure that the bio-engineered lung was mature enough to handle the full load of oxygen on its own.

You can hear Bob McDonald’s (host of Quirks & Quarks, a Canadian Broadcasting Corporation science radio programme) interview lead scientist, Dr. Joan Nichols if you go to here. (Note: I find he overmodulates his voice but some may find he has a ‘friendly’ voice.)

This is an image of the lung scaffold produced by the team,

Lung scaffold in the bioreactor chamber on Day 1 of the experiment, before the cells from the study pig were added. (Credit: Joan Nichols) [downloaded from https://www.cbc.ca/radio/quirks/dec-29-2018-water-on-mars-lab-grown-lungs-and-more-the-biggest-science-stories-of-2018-1.4940811/lab-grown-lungs-are-transplanted-in-pigs-today-they-may-help-humans-tomorrow-1.4940822]

Here’s more technical detail in an August 1, 2018i University of Texas Medical Branch (UTMB) news release (also on EurekAlert), which originally announced the research,

A research team at the University of Texas Medical Branch at Galveston have bioengineered lungs and transplanted them into adult pigs with no medical complication.

In 2014, Joan Nichols and Joaquin Cortiella from The University of Texas Medical Branch at Galveston were the first research team to successfully bioengineer human lungs in a lab. In a paper now available in Science Translational Medicine, they provide details of how their work has progressed from 2014 to the point no complications have occurred in the pigs as part of standard preclinical testing.

“The number of people who have developed severe lung injuries has increased worldwide, while the number of available transplantable organs have decreased,” said Cortiella, professor of pediatric anesthesia. “Our ultimate goal is to eventually provide new options for the many people awaiting a transplant,” said Nichols, professor of internal medicine and associate director of the Galveston National Laboratory at UTMB.

To produce a bioengineered lung, a support scaffold is needed that meets the structural needs of a lung. A support scaffold was created using a lung from an unrelated animal that was treated using a special mixture of sugar and detergent to eliminate all cells and blood in the lung, leaving only the scaffolding proteins or skeleton of the lung behind. This is a lung-shaped scaffold made totally from lung proteins.

The cells used to produce each bioengineered lung came from a single lung removed from each of the study animals. This was the source of the cells used to produce a tissue-matched bioengineered lung for each animal in the study. The lung scaffold was placed into a tank filled with a carefully blended cocktail of nutrients and the animals’ own cells were added to the scaffold following a carefully designed protocol or recipe. The bioengineered lungs were grown in a bioreactor for 30 days prior to transplantation. Animal recipients were survived for 10 hours, two weeks, one month and two months after transplantation, allowing the research team to examine development of the lung tissue following transplantation and how the bioengineered lung would integrate with the body.

All of the pigs that received a bioengineered lung stayed healthy. As early as two weeks post-transplant, the bioengineered lung had established the strong network of blood vessels needed for the lung to survive.

“We saw no signs of pulmonary edema, which is usually a sign of the vasculature not being mature enough,” said Nichols and Cortiella. “The bioengineered lungs continued to develop post-transplant without any infusions of growth factors, the body provided all of the building blocks that the new lungs needed.”

Nichols said that the focus of the study was to learn how well the bioengineered lung adapted and continued to mature within a large, living body. They didn’t evaluate how much the bioengineered lung provided oxygenation to the animal.

“We do know that the animals had 100 percent oxygen saturation, as they had one normal functioning lung,” said Cortiella. “Even after two months, the bioengineered lung was not yet mature enough for us to stop the animal from breathing on the normal lung and switch to just the bioengineered lung.”

For this reason, future studies will look at long-term survival and maturation of the tissues as well as gas exchange capability.

The researchers said that with enough funding, they could grow lungs to transplant into people in compassionate use circumstances within five to 10 years.

“It has taken a lot of heart and 15 years of research to get us this far, our team has done something incredible with a ridiculously small budget and an amazingly dedicated group of people,” Nichols and Cortiella said.

Here’s a citation and another link for the paper,

Production and transplantation of bioengineered lung into a large-animal model by Joan E. Nichols, Saverio La Francesca, Jean A. Niles, Stephanie P. Vega, Lissenya B. Argueta, Luba Frank, David C. Christiani, Richard B. Pyles, Blanca E. Himes, Ruyang Zhang, Su Li, Jason Sakamoto, Jessica Rhudy, Greg Hendricks, Filippo Begarani, Xuewu Liu, Igor Patrikeev, Rahul Pal, Emiliya Usheva, Grace Vargas, Aaron Miller, Lee Woodson, Adam Wacher, Maria Grimaldo, Daniil Weaver, Ron Mlcak, and Joaquin Cortiella. Science Translational Medicine 01 Aug 2018: Vol. 10, Issue 452, eaao3926 DOI: 10.1126/scitranslmed.aao3926

This paper is behind a paywall.

Artificial lung cancer tissue

The research teams at the University of Toronto and the University of Ottawa worked on creating artificial lung tissue but other applications are possible too. First, there’s the announcement in a February 25, 2019 news item on phys.org,

A 3-D hydrogel created by researchers in U of T Engineering Professor Molly Shoichet’s lab is helping University of Ottawa researchers to quickly screen hundreds of potential drugs for their ability to fight highly invasive cancers.

Cell invasion is a critical hallmark of metastatic cancers, such as certain types of lung and brain cancer. Fighting these cancers requires therapies that can both kill cancer cells as well as prevent cell invasion of healthy tissue. Today, most cancer drugs are only screened for their ability to kill cancer cells.

“In highly invasive diseases, there is a crucial need to screen for both of these functions,” says Shoichet. “We now have a way to do this.”

A February 25, 2019 University of Toronto news release (also on EurekAlert), which originated the news item, offers more detail ,

In their latest research, the team used hydrogels to mimic the environment of lung cancer, selectively allowing cancer cells, and not healthy cells, to invade. In their latest research, the team used hydrogels to mimic the environment of lung cancer, selectively allowing cancer cells, and not healthy cells, to invade. This emulated environment enabled their collaborators in Professor Bill Stanford’s lab at University of Ottawa to screen for both cancer-cell growth and invasion. The study, led by Roger Y. Tam, a research associate in Shochet’s lab, was recently published in Advanced Materials.

“We can conduct this in a 384-well plate, which is no bigger than your hand. And with image-analysis software, we can automate this method to enable quick, targeted screenings for hundreds of potential cancer treatments,” says Shoichet.

One example is the researchers’ drug screening for lymphangioleiomyomatosis (LAM), a rare lung disease affecting women. Shoichet and her team were inspired by the work of Green Eggs and LAM, a Toronto-based organization raising awareness of the disease.

Using their hydrogels, they were able to automate and screen more than 800 drugs, thereby uncovering treatments that could target disease growth and invasion.

In the ongoing collaboration, the researchers plan to next screen multiple drugs at different doses to gain greater insight into new treatment methods for LAM. The strategies and insights they gain could also help identify new drugs for other invasive cancers.

Shoichet, who was recently named a Distinguished Woman in Chemistry or Chemical Engineering, also plans to patent the hydrogel technology.

“This has, and continues to be, a great collaboration that is advancing knowledge at the intersection of engineering and biology,” says Shoichet.

I note that Shoichet (pronounced ShoyKet) is getting ready to patent this work. I do have a question about this and it’s not up to Shoichet to answer as she didn’t create the system. Will the taxpayers who funded her work receive any financial benefits should the hydrogel prove to be successful or will we be paying double, both supporting her research and paying for the hydrogel through our healthcare costs?

Getting back to the research, here’s a link to and a citation for the paper,

Rationally Designed 3D Hydrogels Model Invasive Lung Diseases Enabling High‐Content Drug Screening by Roger Y. Tam, Julien Yockell‐Lelièvre, Laura J. Smith, Lisa M. Julian, Alexander E. G. Baker, Chandarong Choey, Mohamed S. Hasim, Jim Dimitroulakos, William L. Stanford, Molly S. Shoichet. Advanced Materials Volume 31, Issue 7 February 15, 2019 1806214 First published online: 27 December 2018 DOI: https://doi.org/10.1002/adma.201806214

This paper is behind a paywall.

A 3D printed eye cornea and a 3D printed copy of your brain (also: a Brad Pitt connection)

Sometimes it’s hard to keep up with 3D tissue printing news. I have two news bits, one concerning eyes and another concerning brains.

3D printed human corneas

A May 29, 2018 news item on ScienceDaily trumpets the news,

The first human corneas have been 3D printed by scientists at Newcastle University, UK.

It means the technique could be used in the future to ensure an unlimited supply of corneas.

As the outermost layer of the human eye, the cornea has an important role in focusing vision.

Yet there is a significant shortage of corneas available to transplant, with 10 million people worldwide requiring surgery to prevent corneal blindness as a result of diseases such as trachoma, an infectious eye disorder.

In addition, almost 5 million people suffer total blindness due to corneal scarring caused by burns, lacerations, abrasion or disease.

The proof-of-concept research, published today [May 29, 2018] in Experimental Eye Research, reports how stem cells (human corneal stromal cells) from a healthy donor cornea were mixed together with alginate and collagen to create a solution that could be printed, a ‘bio-ink’.

Here are the proud researchers with their cornea,

Caption: Dr. Steve Swioklo and Professor Che Connon with a dyed cornea. Credit: Newcastle University, UK

A May 30,2018 Newcastle University press release (also on EurekAlert but published on May 29, 2018), which originated the news item, adds more details,

Using a simple low-cost 3D bio-printer, the bio-ink was successfully extruded in concentric circles to form the shape of a human cornea. It took less than 10 minutes to print.

The stem cells were then shown to culture – or grow.

Che Connon, Professor of Tissue Engineering at Newcastle University, who led the work, said: “Many teams across the world have been chasing the ideal bio-ink to make this process feasible.

“Our unique gel – a combination of alginate and collagen – keeps the stem cells alive whilst producing a material which is stiff enough to hold its shape but soft enough to be squeezed out the nozzle of a 3D printer.

“This builds upon our previous work in which we kept cells alive for weeks at room temperature within a similar hydrogel. Now we have a ready to use bio-ink containing stem cells allowing users to start printing tissues without having to worry about growing the cells separately.”

The scientists, including first author and PhD student Ms Abigail Isaacson from the Institute of Genetic Medicine, Newcastle University, also demonstrated that they could build a cornea to match a patient’s unique specifications.

The dimensions of the printed tissue were originally taken from an actual cornea. By scanning a patient’s eye, they could use the data to rapidly print a cornea which matched the size and shape.

Professor Connon added: “Our 3D printed corneas will now have to undergo further testing and it will be several years before we could be in the position where we are using them for transplants.

“However, what we have shown is that it is feasible to print corneas using coordinates taken from a patient eye and that this approach has potential to combat the world-wide shortage.”

Here’s a link to and a citation for the paper,

3D bioprinting of a corneal stroma equivalent by Abigail Isaacson, Stephen Swioklo, Che J. Connon. Experimental Eye Research Volume 173, August 2018, Pages 188–193 and 2018 May 14 pii: S0014-4835(18)30212-4. doi: 10.1016/j.exer.2018.05.010. [Epub ahead of print]

This paper is behind a paywall.

A 3D printed copy of your brain

I love the title for this May 30, 2018 Wyss Institute for Biologically Inspired Engineering news release: Creating piece of mind by Lindsay Brownell (also on EurekAlert),

What if you could hold a physical model of your own brain in your hands, accurate down to its every unique fold? That’s just a normal part of life for Steven Keating, Ph.D., who had a baseball-sized tumor removed from his brain at age 26 while he was a graduate student in the MIT Media Lab’s Mediated Matter group. Curious to see what his brain actually looked like before the tumor was removed, and with the goal of better understanding his diagnosis and treatment options, Keating collected his medical data and began 3D printing his MRI [magnetic resonance imaging] and CT [computed tomography] scans, but was frustrated that existing methods were prohibitively time-intensive, cumbersome, and failed to accurately reveal important features of interest. Keating reached out to some of his group’s collaborators, including members of the Wyss Institute at Harvard University, who were exploring a new method for 3D printing biological samples.

“It never occurred to us to use this approach for human anatomy until Steve came to us and said, ‘Guys, here’s my data, what can we do?” says Ahmed Hosny, who was a Research Fellow with at the Wyss Institute at the time and is now a machine learning engineer at the Dana-Farber Cancer Institute. The result of that impromptu collaboration – which grew to involve James Weaver, Ph.D., Senior Research Scientist at the Wyss Institute; Neri Oxman, [emphasis mine] Ph.D., Director of the MIT Media Lab’s Mediated Matter group and Associate Professor of Media Arts and Sciences; and a team of researchers and physicians at several other academic and medical centers in the US and Germany – is a new technique that allows images from MRI, CT, and other medical scans to be easily and quickly converted into physical models with unprecedented detail. The research is reported in 3D Printing and Additive Manufacturing.

“I nearly jumped out of my chair when I saw what this technology is able to do,” says Beth Ripley, M.D. Ph.D., an Assistant Professor of Radiology at the University of Washington and clinical radiologist at the Seattle VA, and co-author of the paper. “It creates exquisitely detailed 3D-printed medical models with a fraction of the manual labor currently required, making 3D printing more accessible to the medical field as a tool for research and diagnosis.”

Imaging technologies like MRI and CT scans produce high-resolution images as a series of “slices” that reveal the details of structures inside the human body, making them an invaluable resource for evaluating and diagnosing medical conditions. Most 3D printers build physical models in a layer-by-layer process, so feeding them layers of medical images to create a solid structure is an obvious synergy between the two technologies.

However, there is a problem: MRI and CT scans produce images with so much detail that the object(s) of interest need to be isolated from surrounding tissue and converted into surface meshes in order to be printed. This is achieved via either a very time-intensive process called “segmentation” where a radiologist manually traces the desired object on every single image slice (sometimes hundreds of images for a single sample), or an automatic “thresholding” process in which a computer program quickly converts areas that contain grayscale pixels into either solid black or solid white pixels, based on a shade of gray that is chosen to be the threshold between black and white. However, medical imaging data sets often contain objects that are irregularly shaped and lack clear, well-defined borders; as a result, auto-thresholding (or even manual segmentation) often over- or under-exaggerates the size of a feature of interest and washes out critical detail.

The new method described by the paper’s authors gives medical professionals the best of both worlds, offering a fast and highly accurate method for converting complex images into a format that can be easily 3D printed. The key lies in printing with dithered bitmaps, a digital file format in which each pixel of a grayscale image is converted into a series of black and white pixels, and the density of the black pixels is what defines the different shades of gray rather than the pixels themselves varying in color.

Similar to the way images in black-and-white newsprint use varying sizes of black ink dots to convey shading, the more black pixels that are present in a given area, the darker it appears. By simplifying all pixels from various shades of gray into a mixture of black or white pixels, dithered bitmaps allow a 3D printer to print complex medical images using two different materials that preserve all the subtle variations of the original data with much greater accuracy and speed.

The team of researchers used bitmap-based 3D printing to create models of Keating’s brain and tumor that faithfully preserved all of the gradations of detail present in the raw MRI data down to a resolution that is on par with what the human eye can distinguish from about 9-10 inches away. Using this same approach, they were also able to print a variable stiffness model of a human heart valve using different materials for the valve tissue versus the mineral plaques that had formed within the valve, resulting in a model that exhibited mechanical property gradients and provided new insights into the actual effects of the plaques on valve function.

“Our approach not only allows for high levels of detail to be preserved and printed into medical models, but it also saves a tremendous amount of time and money,” says Weaver, who is the corresponding author of the paper. “Manually segmenting a CT scan of a healthy human foot, with all its internal bone structure, bone marrow, tendons, muscles, soft tissue, and skin, for example, can take more than 30 hours, even by a trained professional – we were able to do it in less than an hour.”

The researchers hope that their method will help make 3D printing a more viable tool for routine exams and diagnoses, patient education, and understanding the human body. “Right now, it’s just too expensive for hospitals to employ a team of specialists to go in and hand-segment image data sets for 3D printing, except in extremely high-risk or high-profile cases. We’re hoping to change that,” says Hosny.

In order for that to happen, some entrenched elements of the medical field need to change as well. Most patients’ data are compressed to save space on hospital servers, so it’s often difficult to get the raw MRI or CT scan files needed for high-resolution 3D printing. Additionally, the team’s research was facilitated through a joint collaboration with leading 3D printer manufacturer Stratasys, which allowed access to their 3D printer’s intrinsic bitmap printing capabilities. New software packages also still need to be developed to better leverage these capabilities and make them more accessible to medical professionals.

Despite these hurdles, the researchers are confident that their achievements present a significant value to the medical community. “I imagine that sometime within the next 5 years, the day could come when any patient that goes into a doctor’s office for a routine or non-routine CT or MRI scan will be able to get a 3D-printed model of their patient-specific data within a few days,” says Weaver.

Keating, who has become a passionate advocate of efforts to enable patients to access their own medical data, still 3D prints his MRI scans to see how his skull is healing post-surgery and check on his brain to make sure his tumor isn’t coming back. “The ability to understand what’s happening inside of you, to actually hold it in your hands and see the effects of treatment, is incredibly empowering,” he says.

“Curiosity is one of the biggest drivers of innovation and change for the greater good, especially when it involves exploring questions across disciplines and institutions. The Wyss Institute is proud to be a space where this kind of cross-field innovation can flourish,” says Wyss Institute Founding Director Donald Ingber, M.D., Ph.D., who is also the Judah Folkman Professor of Vascular Biology at Harvard Medical School (HMS) and the Vascular Biology Program at Boston Children’s Hospital, as well as Professor of Bioengineering at Harvard’s John A. Paulson School of Engineering and Applied Sciences (SEAS).

Here’s an image illustrating the work,

Caption: This 3D-printed model of Steven Keating’s skull and brain clearly shows his brain tumor and other fine details thanks to the new data processing method pioneered by the study’s authors. Credit: Wyss Institute at Harvard University

Here’s a link to and a citation for the paper,

From Improved Diagnostics to Presurgical Planning: High-Resolution Functionally Graded Multimaterial 3D Printing of Biomedical Tomographic Data Sets by Ahmed Hosny , Steven J. Keating, Joshua D. Dilley, Beth Ripley, Tatiana Kelil, Steve Pieper, Dominik Kolb, Christoph Bader, Anne-Marie Pobloth, Molly Griffin, Reza Nezafat, Georg Duda, Ennio A. Chiocca, James R.. Stone, James S. Michaelson, Mason N. Dean, Neri Oxman, and James C. Weaver. 3D Printing and Additive Manufacturing http://doi.org/10.1089/3dp.2017.0140 Online Ahead of Print:May 29, 2018

This paper appears to be open access.

A tangential Brad Pitt connection

It’s a bit of Hollywood gossip. There was some speculation in April 2018 that Brad Pitt was dating Dr. Neri Oxman highlighted in the Wyss Institute news release. Here’s a sample of an April 13, 2018 posting on Laineygossip (Note: A link has been removed),

It took him a long time to date, but he is now,” the insider tells PEOPLE. “He likes women who challenge him in every way, especially in the intellect department. Brad has seen how happy and different Amal has made his friend (George Clooney). It has given him something to think about.”

While a Pitt source has maintained he and Oxman are “just friends,” they’ve met up a few times since the fall and the insider notes Pitt has been flying frequently to the East Coast. He dropped by one of Oxman’s classes last fall and was spotted at MIT again a few weeks ago.

Pitt and Oxman got to know each other through an architecture project at MIT, where she works as a professor of media arts and sciences at the school’s Media Lab. Pitt has always been interested in architecture and founded the Make It Right Foundation, which builds affordable and environmentally friendly homes in New Orleans for people in need.

“One of the things Brad has said all along is that he wants to do more architecture and design work,” another source says. “He loves this, has found the furniture design and New Orleans developing work fulfilling, and knows he has a talent for it.”

It’s only been a week since Page Six first broke the news that Brad and Dr Oxman have been spending time together.

I’m fascinated by Oxman’s (and her colleagues’) furniture. Rose Brook writes about one particular Oxman piece in her March 27, 2014 posting for TCT magazine (Note: Links have been removed),

MIT Professor and 3D printing forerunner Neri Oxman has unveiled her striking acoustic chaise longue, which was made using Stratasys 3D printing technology.

Oxman collaborated with Professor W Craig Carter and Composer and fellow MIT Professor Tod Machover to explore material properties and their spatial arrangement to form the acoustic piece.

Christened Gemini, the two-part chaise was produced using a Stratasys Objet500 Connex3 multi-colour, multi-material 3D printer as well as traditional furniture-making techniques and it will be on display at the Vocal Vibrations exhibition at Le Laboratoire in Paris from March 28th 2014.

An Architect, Designer and Professor of Media, Arts and Science at MIT, Oxman’s creation aims to convey the relationship of twins in the womb through material properties and their arrangement. It was made using both subtractive and additive manufacturing and is part of Oxman’s ongoing exploration of what Stratasys’ ground-breaking multi-colour, multi-material 3D printer can do.

Brook goes on to explain how the chaise was made and the inspiration that led to it. Finally, it’s interesting to note that Oxman was working with Stratasys in 2014 and that this 2018 brain project is being developed in a joint collaboration with Statasys.

That’s it for 3D printing today.

Repairing a ‘broken’ heart with a 3D printed patch

The idea of using stem cells to help heal your heart so you don’t have scar tissue seems to be a step closer to reality. From an April 14, 2017 news item on ScienceDaily which announces the research and explains why scar tissue in your heart is a problem,

A team of biomedical engineering researchers, led by the University of Minnesota, has created a revolutionary 3D-bioprinted patch that can help heal scarred heart tissue after a heart attack. The discovery is a major step forward in treating patients with tissue damage after a heart attack.

According to the American Heart Association, heart disease is the No. 1 cause of death in the U.S. killing more than 360,000 people a year. During a heart attack, a person loses blood flow to the heart muscle and that causes cells to die. Our bodies can’t replace those heart muscle cells so the body forms scar tissue in that area of the heart, which puts the person at risk for compromised heart function and future heart failure.

An April 13, 2017 University of Minnesota news release (also on EurekAlert but dated April 14, 2017), which originated the news item, describes the work in more detail,

In this study, researchers from the University of Minnesota-Twin Cities, University of Wisconsin-Madison, and University of Alabama-Birmingham used laser-based 3D-bioprinting techniques to incorporate stem cells derived from adult human heart cells on a matrix that began to grow and beat synchronously in a dish in the lab.

When the cell patch was placed on a mouse following a simulated heart attack, the researchers saw significant increase in functional capacity after just four weeks. Since the patch was made from cells and structural proteins native to the heart, it became part of the heart and absorbed into the body, requiring no further surgeries.

“This is a significant step forward in treating the No. 1 cause of death in the U.S.,” said Brenda Ogle, an associate professor of biomedical engineering at the University of Minnesota. “We feel that we could scale this up to repair hearts of larger animals and possibly even humans within the next several years.”

Ogle said that this research is different from previous research in that the patch is modeled after a digital, three-dimensional scan of the structural proteins of native heart tissue.  The digital model is made into a physical structure by 3D printing with proteins native to the heart and further integrating cardiac cell types derived from stem cells.  Only with 3D printing of this type can we achieve one micron resolution needed to mimic structures of native heart tissue.

“We were quite surprised by how well it worked given the complexity of the heart,” Ogle said.  “We were encouraged to see that the cells had aligned in the scaffold and showed a continuous wave of electrical signal that moved across the patch.”

Ogle said they are already beginning the next step to develop a larger patch that they would test on a pig heart, which is similar in size to a human heart.

The researchers has made this video of beating heart cells in a petri dish available,

Date: Published on Apr 14, 2017

Caption: Researchers used laser-based 3D-bioprinting techniques to incorporate stem cells derived from adult human heart cells on a matrix that began to grow and beat synchronously in a dish in the lab. Credit: Brenda Ogle, University of Minnesota

Here’s a link to and a citation for the paper,

Myocardial Tissue Engineering With Cells Derived From Human-Induced Pluripotent Stem Cells and a Native-Like, High-Resolution, 3-Dimensionally Printed Scaffold by Ling Gao, Molly E. Kupfer, Jangwook P. Jung, Libang Yang, Patrick Zhang, Yong Da Sie, Quyen Tran, Visar Ajeti, Brian T. Freeman, Vladimir G. Fast, Paul J. Campagnola, Brenda M. Ogle, Jianyi Zhang. Circulation Research April 14, 2017, Volume 120, Issue 8 https://doi.org/10.1161/CIRCRESAHA.116.310277 Circulation Research. 2017;120:1318-1325 Originally published online] January 9, 2017

This paper appears to be open access.

A new platform for culturing stem cells: a Multiplexed Artificial Cellular Microenvironment array

Japanese scientists have developed a more precise method for culturing stem cells according to a March 14, 2017 news item on Nanowerk,

A team of researchers in Japan has developed a new platform for culturing human pluripotent stem cells that provides far more control of culture conditions than previous tools by using micro and nanotechnologies.

The Multiplexed Artificial Cellular Microenvironment (MACME) array places nanofibres, mimicking cellular matrices, into fluid-filled micro-chambers of precise sizes, which mimic extracellular environments.

Caption: The Multiplexed Artificial Cellular Microenvironment (MACME) array, consisted with a microfluidic structure and nanofibre array for mimicking cellular microenvironments. Credit: Kyoto University iCeMS

A March 17, 2017 Kyoto University press release (also on EurekAlert), which originated the news item, explains the research in more detail,

Human pluripotent stems cells (hPSCs) hold great promise for tissue engineering, regenerative medicine and cell-based therapies because they can become any type of cell. The environment surrounding the cells plays a major role in determining what tissues they become, if they replicate into more cells, or die. However, understanding these interactions has been difficult because researchers have lacked tools that work on the appropriate scale.

Often, stem cells are cultured in a cell culture medium in small petri dishes. While factors such as medium pH levels and nutrients can be controlled, the artificial set up is on the macroscopic scale and does not allow for precise control of the physical environment surrounding the cells.

The MACME array miniaturizes this set up, culturing stem cells in rows of micro-chambers of cell culture medium. It also takes it a step further by placing nanofibers in these chambers to mimic the structures found around cells.

Led by Ken-ichiro Kamei of Kyoto University’s Institute for Integrated Cell-Material Sciences (iCeMS), the team tested a variety of nanofiber materials and densities, micro-chamber heights and initial stem cell densities to determine the best combination that encourages human pluripotent stem cells to replicate.

They stained the cells with several fluorescent markers and used a microscope to see if the cells died, replicated or differentiated into tissues.

Their analysis revealed that gelatin nanofibers and medium-sized chambers that create medium seed cell density provided the best environment for the stem cells to continue to multiply. The quantity and density of neighboring cells strongly influences cell survival.

The array is an “optimal and powerful approach for understanding how environmental cues regulate cellular functions,” the researchers conclude in a recently published paper in the journal Small.

This array appears to be the first time multiple kinds of extracellular environments can be mounted onto a single device, making it much easier to compare how different environments influence cells.

The MACME array could substantially reduce experiment costs compared to conventional tools, in part because it is low volume and requires less cell culture medium. The array does not require any special equipment and is compatible with both commonly used laboratory pipettes and automated pipette systems for performing high-throughput screening.

Here’s a link to and a citation for the paper,

Microfluidic-Nanofiber Hybrid Array for Screening of Cellular Microenvironments by Ken-ichiro Kamei, Yasumasa Mashimo, Momoko Yoshioka, Yumie Tokunaga, Christopher Fockenberg, Shiho Terada, Yoshie Koyama, Minako Nakajima, Teiko Shibata-Seki, Li Liu, Toshihiro Akaike, Eiry Kobatake, Siew-Eng How, Motonari Uesugi, and Yong Chen. Small DOI: 10.1002/smll.201603104 Version of Record online: 8 MAR 2017

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

York University (Toronto, Ontario, Canada) research team creates 3D beating heart and matters of the heart at the Ontario Institute for Regenerative Medicine

I have two items about cardiac research in Ontario. Not strictly speaking about nanotechnology, the two items do touch on topics covered here before, 3D organs and stem cells.

York University and its 3D beating heart

A Feb. 9, 2017 York University news release (also on EurekAlert), describe an innovative approach to creating 3D heart tissue,

Matters of the heart can be complicated, but York University scientists have found a way to create 3D heart tissue that beats in synchronized harmony, like a heart in love, that will lead to better understanding of cardiac health, and improved treatments.

York U chemistry Professor Muhammad Yousaf and his team of grad students have devised a way to stick three different types of cardiac cells together, like Velcro, to make heart tissue that beats as one.

Until now, most 2D and 3D in vitro tissue did not beat in harmony and required scaffolding for the cells to hold onto and grow, causing limitations. In this research, Yousaf and his team made a scaffold free beating tissue out of three cell types found in the heart – contractile cardiac muscle cells, connective tissue cells and vascular cells.

The researchers believe this is the first 3D in vitro cardiac tissue with three cell types that can beat together as one entity rather than at different intervals.

“This breakthrough will allow better and earlier drug testing, and potentially eliminate harmful or toxic medications sooner,” said Yousaf of York U’s Faculty of Science.

In addition, the substance used to stick cells together (ViaGlue), will provide researchers with tools to create and test 3D in vitro cardiac tissue in their own labs to study heart disease and issues with transplantation. Cardiovascular associated diseases are the leading cause of death globally and are responsible for 40 per cent of deaths in North America.

“Making in vitro 3D cardiac tissue has long presented a challenge to scientists because of the high density of cells and muscularity of the heart,” said Dmitry Rogozhnikov, a chemistry PhD student at York. “For 2D or 3D cardiac tissue to be functional it needs the same high cellular density and the cells must be in contact to facilitate synchronized beating.”

Although the 3D cardiac tissue was created at a millimeter scale, larger versions could be made, said Yousaf, who has created a start-up company OrganoLinX to commercialize the ViaGlue reagent and to provide custom 3D tissues on demand.

Here’s a link to and a citation for the paper,

Scaffold Free Bio-orthogonal Assembly of 3-Dimensional Cardiac Tissue via Cell Surface Engineering by Dmitry Rogozhnikov, Paul J. O’Brien, Sina Elahipanah, & Muhammad N. Yousaf. Scientific Reports 6, Article number: 39806 (2016) doi:10.1038/srep39806 Published online: 23 December 2016

This paper is open access.

Ontario Institute for Regenerative Medicine and its heart stem cell research

Steven Erwood has written about how Toronto has become a centre for certain kinds of cardiac research by focusing on specific researchers in a Feb. 13, 2017 posting on the Ontario Institute for Regenerative Medicine’s expression blog (Note: Links have been removed),

You may have heard that Paris is the city of love, but you might not know that Toronto specializes in matters of the heart, particularly broken hearts.

Dr. Ren Ke Li, an investigator with the Ontario Institute for Regenerative Medicine, established his lab at the Toronto General Hospital Research Institute in 1993 hoping to find a way to replace the muscle cells, or cardiomyocytes, that are lost after a heart attack. Specifically, Li hoped to transplant a collection of cells, called stem cells, into a heart damaged by a heart attack. Stem cells have the power to differentiate into virtually any cell type, so if Li could coax them to become cardiomyocytes, they could theoretically reverse the damage caused by the heart attack.

Over the years, Li’s experiments using stem cells to regenerate and repair damaged heart tissue, which progressed all the way through to human clinical trials, pushed Li to rethink his approach to heart repair. Most of the transplanted cells failed to engraft to the host tissue and many of those that did successfully integrate into the patient’s heart remained non-contractile, sitting still beside the rest of the beating heart muscle. Despite this, the treatments were still proving beneficial — albeit less beneficial than Li had hoped. These cells weren’t replacing the lost cardiomyocytes, but they were still helping the patient recover. Li was then just beginning to reveal something that is now well described: transplanting exogenous stem cells (originating outside the patient) onto damaged tissue stimulated the endogenous stem cells to repair that damage. These transplanted stem cells were changing the behaviour of the patient’s own stem cells, enhancing their response to injury.

Li calls this process “rejuvenation” — arguing that the reason older populations can’t recover from cardiac injury is because they have fewer stem cells, and those stem cells have lost their ability to repair and regenerate damaged tissue over time. Li argues that the positive effects he was seeing in his experiments and clinical trials was a restoration or reversal of age-related deterioration in repair capability — a rejuvenation of the aged heart.

Li, alongside fellow OIRM [Ontario Institute for Regenerative Medicine] researcher and cardiac surgeon at Toronto General Hospital, Dr. Richard Weisel, dedicated a large part of their research effort to understanding this process. Weisel explains, “We put young cells into old animals, and we can get them to respond to a heart attack like a young person — which is remarkable!”

A team of researchers led by the duo published an article in Basic Research in Cardiology last month describing a new method to rejuvenate the aged heart, and characterizing this rejuvenation at the molecular and cellular level.

Successfully advancing this research to the clinic is where Weisel thinks Toronto provides a unique advantage. “We have the ability to do the clinical trials — the same people who are working on these projects [in the lab], can also take them into the clinic, and a lot of other places in the world [the clinicians and the researchers] are separate. We’ve been doing that for all the areas of stem cell research.” This unique set of circumstances, Weisel argues, more readily allows for a successful transition from research to clinical practice.

But an integrated research and clinical environment isn’t all the city has to offer to those looking to make substantial progress in stem cell therapies. Dr. Michael Laflamme, OIRM researcher and a leading authority on stem cell therapies for cardiac repair, called his decision to relocate to Toronto from the University of Washington in Seattle “a no-brainer”.

Laflamme focuses on improving the existing approaches to exogenous stem cell transplantation in cardiac repair and believes that solving the problems Li faced in his early experiments is just a matter of finding the right cell type. Laflamme, in an ongoing preclinical trial funded by OIRM, is differentiating stem cells in a bioreactor into ventricular cardiomyocytes, the specific type of cell lost after a heart attack, and delivering those cells directly to the scar tissue in hopes of turning it back into muscle. Laflamme is optimistic these ventricular cardiomyocytes might be just the cell type he’s looking for. Using these cells in animal models, although in a mixture of other cardiac cell types, Laflamme explains, “We’ve shown that those cells will stably engraft and they actually become electrically integrated with the rest of the tissue — they will [beat] in synchrony with the rest of the heart.”

Laflamme states that “Toronto is the place where we can get this stuff done better and we can get it done faster,” citing the existing Toronto-based expertise in both the differentiation of stem cells and the biotechnological means to scale these processes as being unparalleled elsewhere in the world.

It’s not only academic researchers and clinicians that recognize Toronto’s potential to advance regenerative medicine and stem cell therapy. Pharmaceutical giant Bayer, partnered with San Francisco-based venture capital firm Versant Ventures, announced last December a USD 225 million investment in a stem cell biotechnology company called BlueRock Therapeutics — the second largest investment of it’s kind in the history of the biotechnology industry. …

There’s substantially to more Erwood’s piece in the original posting.

One final thought, I wonder if there is a possibility that York University’s ViaGlue might be useful in the work talking place at Ontario Institute for Regenerative Medicine. I realize the two institutions are in the same city but do the researchers even know about each other’s work?

Better technique for growing organoids taking them from the lab to the clinic

A Nov. 16, 2016 École Polytechnique Fédérale de Lausanne (EPFL) press release (also on EurekAlert) describes a new material for growing organoids,

Organoids are miniature organs that can be grown in the lab from a person’s stem cells. They can be used to model diseases, and in the future could be used to test drugs or even replace damaged tissue in patients. But currently organoids are very difficult to grow in a standardized and controlled way, which is key to designing and using them. EPFL scientists have now solved the problem by developing a patent-pending “hydrogel” that provides a fully controllable and tunable way to grow organoids. …

Organoids need a 3D scaffold

Growing organoids begins with stem cells — immature cells that can grow into any cell type of the human body and that play key roles in tissue function and regeneration. To form an organoid, the stem cells are grown inside three-dimensional gels that contain a mix of biomolecules that promote stem cell renewal and differentiation.

The role of these gels is to mimic the natural environment of the stem cells, which provides them with a protein- and sugar-rich scaffold called the “extracellular matrix”, upon which the stem cells build specific body tissues. The stem cells stick to the extracellular matrix gel, and then “self-organize” into miniature organs like retinas, kidneys, or the gut. These tiny organs retain key aspects of their real-life biology, and can be used to study diseases or test drugs before moving on to human trials.

But the current gels used for organoid growth are derived from mice, and have problems. First, it is impossible to control their makeup from batch to batch, which can cause stem cells to behave inconsistently. Second, their biochemical complexity makes them very difficult to fine-tune for studying the effect of different parameters (e.g. biological molecules, mechanical properties, etc.) on the growth of organoids. Finally, the gels can carry pathogens or immunogens, which means that they are not suitable for growing organoids to be used in the clinic.

A hydrogel solution

The lab of Matthias Lütolf at EPFL’s Institute of Bioengineering has developed a synthetic “hydrogel” that eschews the limitations of conventional, naturally derived gels. The patent-pending gel is made of water and polyethylene glycol, a substance used widely today in various forms, from skin creams and toothpastes to industrial applications and, as in this case, bioengineering.

Nikolce Gjorevski, the first author of the study, and his colleagues used the hydrogel to grow stem cells of the gut into a miniature intestine. The functional hydrogel was not only a goal in and of itself, but also a means to identify the factors that influence the stem cells’ ability to expand and form organoids. By carefully tweaking the hydrogel’s properties, they discovered that separate stages of the organoid formation process require different mechanical environments and biological components.

One such factor is a protein called fibronectin, which helps the stem cells attach to the hydrogel. Lütolf’s lab found that this attachment itself is immensely important for growing organoids, as it triggers a whole host of signals to the stem cell that tell it to grow and build an intestine-like structure. The researchers also discovered an essential role for the mechanical properties, i.e. the physical stiffness, of the gel in regulating intestinal stem cell behavior, shedding light on how cells are able to sense, process and respond to physical stimuli. This insight is particularly valuable – while the influence of biochemical signals on stem cells is well-understood, the effect of physical factors has been more mysterious.

Because the hydrogel is man-made, it is easy to control its chemical composition and key properties, and ensure consistency from batch to batch. And because it is artificial, it does not carry any risk of infection or triggering immune responses. As such, it provides a means of moving organoids from basic research to actual pharmaceutical and clinical applications in the future.

Lütolf’s lab is now researching other types of stem cells in order to extend the capacities of their hydrogel into other tissues.

Here’s a link to and a citation for the paper,

Designer matrices for intestinal stem cell and organoid culture by Nikolce Gjorevski, Norman Sachs, Andrea Manfrin, Sonja Giger, Maiia E. Bragina, Paloma Ordóñez-Morán, Hans Clevers, & Matthias P. Lutolf.  Nature (2016) doi:10.1038/nature20168 Published online 16 November 2016

This paper is behind a paywall.