Tag Archives: Wake Forest Baptist Medical Center

Nanoscale measurements for osteoarthritis biomarker

There’s a new technique for measuring hyaluronic acid (HA), which appears to be associated with osteoarthritis. A March 12, 2018 news item on ScienceDaily makes the announcement,

For the first time, scientists at Wake Forest Baptist Medical Center have been able to measure a specific molecule indicative of osteoarthritis and a number of other inflammatory diseases using a newly developed technology.

This preclinical [emphasis mine] study used a solid-state nanopore sensor as a tool for the analysis of hyaluronic acid (HA).

I looked at the abstract for the paper (citation and link follow at end of this post) and found that it has been tested on ‘equine models’. Presumably they mean horses or, more accurately, members of the horse family. The next step is likely to be testing on humans, i.e., clinical trials.

A March 12, 2018 Wake Forest Baptist Medical Center news release (also on EurekAlert), which originated the news item, provides more details,

HA is a naturally occurring molecule that is involved in tissue hydration, inflammation and joint lubrication in the body. The abundance and size distribution of HA in biological fluids is recognized as an indicator of inflammation, leading to osteoarthritis and other chronic inflammatory diseases. It can also serve as an indicator of how far the disease has progressed.

“Our results established a new, quantitative method for the assessment of a significant molecular biomarker that bridges a gap in the conventional technology,” said lead author Adam R. Hall, Ph.D., assistant professor of biomedical engineering at Wake Forest School of Medicine, part of Wake Forest Baptist.

“The sensitivity, speed and small sample requirements of this approach make it attractive as the basis for a powerful analytic tool with distinct advantages over current assessment technologies.”

The most widely used method is gel electrophoresis, which is slow, messy, semi-quantitative, and requires a lot of starting material, Hall said. Other technologies include mass spectrometry and size-exclusion chromatography, which are expensive and limited in range, and multi-angle light scattering, which is non-quantitative and has limited precision.

The study, which is published in the current issue of Nature Communications, was led by Hall and Elaheh Rahbar, Ph.D., of Wake Forest Baptist, and conducted in collaboration with scientists at Cornell University and the University of Oklahoma.

In the study, Hall, Rahbar and their team first employed synthetic HA polymers to validate the measurement approach. They then used the platform to determine the size distribution of as little as 10 nanograms (one-billionth of a gram) of HA extracted from the synovial fluid of a horse model of osteoarthritis.

The measurement approach consists of a microchip with a single hole or pore in it that is a few nanometers wide – about 5,000 times smaller than a human hair. This is small enough that only individual molecules can pass through the opening, and as they do, each can be detected and analyzed. By applying the approach to HA molecules, the researchers were able to determine their size one-by-one. HA size distribution changes over time in osteoarthritis, so this technology could help better assess disease progression, Hall said.

“By using a minimally invasive procedure to extract a tiny amount of fluid – in this case synovial fluid from the knee – we may be able to identify the disease or determine how far it has progressed, which is valuable information for doctors in determining appropriate treatments,” he said.

Hall, Rahbar and their team hope to conduct their next study in humans, and then extend the technology with other diseases where HA and similar molecules play a role, including traumatic injuries and cancer.

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

Label-free analysis of physiological hyaluronan size distribution with a solid-state nanopore sensor by Felipe Rivas, Osama K. Zahid, Heidi L. Reesink, Bridgette T. Peal, Alan J. Nixon, Paul L. DeAngelis, Aleksander Skardal, Elaheh Rahbar, & Adam R. Hall. Nature Communications volume 9, Article number: 1037 (2018) doi:10.1038/s41467-018-03439-x
Published online: 12 March 2018

This paper is open access.

Feasibility of printing ear, bone, and muscle structures

Over ten years ago I attended a show at the Vancouver (Canada) Art Gallery titled ‘Massive Change’ where I saw part of a nose or ear being grown in a petri dish (the work was from an Israeli laboratory) and that was my introduction to tissue engineering. For anyone who’s been following the tissue engineering story, 3D printers have sped up the growth process considerably. More recently, researchers at Wake Forest Baptist Medical Center (North Carolina, US) have announced another step forward for growing organs and body parts, from a Feb. 15, 2016 Wake Forest Baptist Medical Center news release on EurekAlert,

Using a sophisticated, custom-designed 3D printer, regenerative medicine scientists at Wake Forest Baptist Medical Center have proved that it is feasible to print living tissue structures to replace injured or diseased tissue in patients.

Reporting in Nature Biotechnology, the scientists said they printed ear, bone and muscle structures. When implanted in animals, the structures matured into functional tissue and developed a system of blood vessels. Most importantly, these early results indicate that the structures have the right size, strength and function for use in humans.

“This novel tissue and organ printer is an important advance in our quest to make replacement tissue for patients,” said Anthony Atala, M.D., director of the Wake Forest Institute for Regenerative Medicine (WFIRM) and senior author on the study. “It can fabricate stable, human-scale tissue of any shape. With further development, this technology could potentially be used to print living tissue and organ structures for surgical implantation.”

With funding from the Armed Forces Institute of Regenerative Medicine, a federally funded effort to apply regenerative medicine to battlefield injuries, Atala’s team aims to implant bioprinted muscle, cartilage and bone in patients in the future.

Tissue engineering is a science that aims to grow replacement tissues and organs in the laboratory to help solve the shortage of donated tissue available for transplants. The precision of 3D printing makes it a promising method for replicating the body’s complex tissues and organs. However, current printers based on jetting, extrusion and laser-induced forward transfer cannot produce structures with sufficient size or strength to implant in the body.

The Integrated Tissue and Organ Printing System (ITOP), developed over a 10-year period by scientists at the Institute for Regenerative Medicine, overcomes these challenges. The system deposits both bio-degradable, plastic-like materials to form the tissue “shape” and water-based gels that contain the cells. In addition, a strong, temporary outer structure is formed. The printing process does not harm the cells.

A major challenge of tissue engineering is ensuring that implanted structures live long enough to integrate with the body. The Wake Forest Baptist scientists addressed this in two ways. They optimized the water-based “ink” that holds the cells so that it promotes cell health and growth and they printed a lattice of micro-channels throughout the structures. These channels allow nutrients and oxygen from the body to diffuse into the structures and keep them live while they develop a system of blood vessels.

It has been previously shown that tissue structures without ready-made blood vessels must be smaller than 200 microns (0.007 inches) for cells to survive. In these studies, a baby-sized ear structure (1.5 inches) survived and showed signs of vascularization at one and two months after implantation.

“Our results indicate that the bio-ink combination we used, combined with the micro-channels, provides the right environment to keep the cells alive and to support cell and tissue growth,” said Atala.

Another advantage of the ITOP system is its ability to use data from CT and MRI scans to “tailor-make” tissue for patients. For a patient missing an ear, for example, the system could print a matching structure.

Several proof-of-concept experiments demonstrated the capabilities of ITOP. To show that ITOP can generate complex 3D structures, printed, human-sized external ears were implanted under the skin of mice. Two months later, the shape of the implanted ear was well-maintained and cartilage tissue and blood vessels had formed.

To demonstrate the ITOP can generate organized soft tissue structures, printed muscle tissue was implanted in rats. After two weeks, tests confirmed that the muscle was robust enough to maintain its structural characteristics, become vascularized and induce nerve formation.

And, to show that construction of a human-sized bone structure, jaw bone fragments were printed using human stem cells. The fragments were the size and shape needed for facial reconstruction in humans. To study the maturation of bioprinted bone in the body, printed segments of skull bone were implanted in rats. After five months, the bioprinted structures had formed vascularized bone tissue.

Ongoing studies will measure longer-term outcomes.

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The research was supported, in part, by grants from the Armed Forces Institute of Regenerative Medicine (W81XWH-08-2-0032), the Telemedicine and Advanced Technology Research Center at the U.S. Army Medical Research and Material Command (W81XWH-07-1-0718) and the Defense Threat Reduction Agency (N66001-13-C-2027).

(Sometimes the information about the funding agencies is almost as interesting as the research.) Here’s a link to and a citation for the paper,

A 3D bioprinting system to produce human-scale tissue constructs with structural integrity by Hyun-Wook Kang, Sang Jin Lee, In Kap Ko, Carlos Kengla, James J Yoo, & Anthony Atala. Nature Biotechnology (2016)  doi:10.1038/nbt.3413 Published online 15 February 2016

This paper is behind a paywall.

As you can see, despite being printed, this latest ear is also spending time in a dish,

WakeBaptistEar

Courtesy: Wake Forest Baptist Medical Center