A group of Indian scientists have brought hope for people suffering from osteoarthritis, a common debilitating disease of the joints of hands and legs. They have developed the first bio-printed cartilage, which can be potentially grafted onto affected joint sites to heal the cartilage lesions.
The bio-printed cartilage developed through a collaborative effort by IIT Delhi and IIT Kanpur is molecularly similar to natural cartilage. The research is a breakthrough since numerous attempts over 30 years to develop tissue engineered joint cartilage found in the knees with suitable load bearing capacity have been so far unsuccessful.
The paper accepted for publication in the journal bioprinting sets the stage for generating patient specific cartilage for future implantation.
The research supported by the Department of Biotechnology (DBT) combined the Tissue engineering and 3D bioprinting expertise at IIT Delhi with Developmental biology expertise at IIT Kanpur. 3D bioprinting is an emerging strategy of creating three-dimensional, anatomical tissue-resembling patterns using additive manufacturing technology, where cell function and viability are preserved within the patient-specific or defect site-specific printed construct. Bioinks are materials that mimic an extracellular matrix environment to support the adhesion, proliferation and differentiation of mammalian cells. They used silk-gelatin bioink to create the tailor-made cellular micro-environment required in the petri dish to nurture the bone marrow derived stem cells to joint cartilage in four weeks – a challenge of sorts. Interestingly, in this study they generated valuable insight how chemical composition and physical properties of this silk-gelatin modulated cellular signaling pathways crucial for articular cartilage differentiation and induction of hypertrophy during chondrogenic differentiation. Hence, the team’s 3D bioprinting approach sets the pathway for converting bone-marrow derived stem cells gradually to chondrocyte-like cells (specialised cells, which produce and maintain the extracellular matrix of cartilage) and at the same time stopped their conversion to bone cells and thus remains as stable articular cartilage. While articular cartilage is stable, permanent and sponge like with high load bearing capacity, transient cartilage becomes bone cells and, therefore, brittle within a short time.
This work, which is the first successful attempt to characterize engineered cartilage as permanent or transient cartilage and produce the former in the laboratory, is still trying to overcome another hurdle in applying it to treat osteoarthritis. The scientists will now have to test whether the cartilage developed will maintain its nature when implanted in an osteoarthritic cartilage tissue given that osteoarthritis promotes conversion of permanent cartilage to transient cartilage. That is what they are aiming to do now.