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Michael Albro, an assistant professor at the College of Engineering, is working to develop innovative growth factor delivery strategies to overcome several of the major challenges in cartilage tissue engineering.<\/p>\n<\/div>\n
By Sarah Wells (COM\u201918) BU Today<\/a><\/em><\/p>\n TAKEAWAYS:<\/strong> When imagining a patient suffering from osteoarthritis you might picture a grandmother struggling with hip pain or a grandfather whose fingers are too stiff to play a melody on piano keys. But the disease, which affects over 30 million Americans, is much more pervasive than that. It may claim less lives than heart disease or breast cancer, but the daily wear and tear of the cushioning cartilage between joints can result in serious pain and, if not treated, permanent disability.<\/p>\n Patients can treat their pain with medication or slow the degeneration through lifestyle changes, but ultimately the loss of cartilage is irreplaceable. Since the emergence of the tissue engineering field in the 1990s, tissue engineers have been working to develop fast and sustainable methods to recreate articular cartilage in a lab that can be clinically implanted into a patient\u2019s joints. The field has seen progress in the past several decades; however, perfectly recreating the tissue has proven more challenging than scientists initially believed. Clinical studies in the field have been largely disappointing.<\/p>\n But research from the Growth Factor Mechanobiology Lab<\/a> of Michael Albro<\/a>, a College of Engineering assistant professor of mechanical engineering, biomedical engineering, and materials science and engineering, has shown promise in developing a method to grow the tissue without the typical instability or imperfections associated with engineered cartilage.<\/p>\n Typically, when biomedical engineers construct cartilage in a lab, they build a nurturing, jelly-like environment in a petri dish and introduce proteins, called growth factors, that help the cells decide what they\u2019ll be when they grow up.<\/p>\n <\/p>\n \u201cThese growth factors are present in the body at very low concentrations, but they\u2019re incredibly potent,\u201d says Albro. \u201cIn a space of just the size of a cell, only a few molecules are present. And if you contrast that with nutrients we\u2019re more familiar with, like glucose, you\u2019re talking about billions of molecules in that same space.\u201d<\/p>\n<\/div>\n A common growth factor, TGF-Beta, is an essential part of growing cartilage, but one that Albro says the field does not yet completely understand.<\/p>\n In the body, these few TGF-Beta proteins start out in an inactive form and are activated slowly through the body\u2019s masterful regulatory system that gradually releases their active form through the dissolving of a protective shell\u2014almost like a gel capsule. But to see faster results in the lab, Albro says that it has been common practice to add these proteins already in their active form, and in concentrations much higher than naturally occur in the body.<\/p>\n \u201cWhat we\u2019re understanding now is that these supraphysiologic doses of TGF-Beta can actually give rise to signs of pathology,\u201d says Albro. \u201cIf you look closer at the tissue being formed, it\u2019s far from ideal.\u201d<\/p>\n These pathologies include degeneration\u2014ironically, much like that which occurs in the natural cartilage of osteoarthritic patients\u2014and the production of a much less pliable form of collagen typically found in bone instead of cartilage. Interestingly, this has been a phenomenon studied by developmental biologists for some time now. Their work has shown that excessive levels of the active form of TGF-Beta can lead to all kinds of pathologies, including cancer and fibrosis.<\/p>\n \u201cI was always struck by the disparity in perspectives by researchers in these two fields,\u201d says Albro. \u201cEngineers are adept at quickly achieving functional outcomes, but the developmental biologists have this very sophisticated understanding of how these growth factors act in the body. There\u2019s incredible value in both perspectives.\u201d<\/p>\n And that truth is evident in the results that Albro\u2019s lab has seen when trying to more thoughtfully grow cartilage. Instead of adding extremely high concentrations of the TGF-Beta in its active form, Albro\u2019s lab is adding TGF-Beta at natural levels in its inactive form, letting it be used by the cells as they need it\u2014just as the body does it. While still in its preliminary stages, Albro says that this bio-inspired method can grow cartilage in a month with results that much more closely match that of natural cartilage.<\/p>\n \u201cWe think this could very easily become the gold standard of all musculoskeletal tissue engineering,\u201d said Albro. \u201cBecause TGF-Beta is so ubiquitous in all these fields, this is applicable to tendons, ligaments, etc. All these different tissues could really benefit.\u201d<\/p>\n
\n\u2022 Albro and his lab are bringing together two sides of the scientific debate\u2014engineers and developmental scientists<\/strong>
\n\u2022 Growing cartilage tissue is not as simple as people once thought, but scientists are making important progress<\/strong><\/p>\n
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