Technique uses 3-D weaving to grow a living hip replacement
With a goal of treating worn, arthritic hips without extensive surgery to replace them, scientists have programmed stem cells to grow new cartilage on a 3-D template shaped like the ball of a hip joint. What’s more, using gene therapy, they have activated the new cartilage to release anti-inflammatory molecules to fend off a return of arthritis.
The technique, demonstrated in a collaborative effort between Washington University School of Medicine in St. Louis and Cytex Therapeutics Inc. in Durham, N.C., is described July 18 in Proceedings of the National Academy of Sciences.
The discovery one day may provide an alternative to hip-replacement surgery, particularly in younger patients. Doctors are reluctant to perform such operations in patients under age 50 because prosthetic joints typically last for less than 20 years. A second joint-replacement surgery to remove a worn prosthetic can destroy bone and put patients at risk for infection.
“Replacing a failed prosthetic joint is a difficult surgery,” said Farshid Guilak, PhD, a professor of orthopedic surgery at Washington University. “We’ve developed a way to resurface an arthritic joint using a patient’s own stem cells to grow new cartilage, combined with gene therapy to release anti-inflammatory molecules to keep arthritis at bay. Our hope is to prevent, or at least delay, a standard metal and plastic prosthetic joint replacement.”
Scientists have developed a material that can mimic cartilage and potentially encourage it to re-grow.
Cartilage is flexible connective tissue found in places such as in joints and between vertebrae in the spine. Compared to other types of connective tissue it is not easy to repair.
The researchers from Imperial College London and the University of Milano-Bicoccahave developed a bio-glass material that mimics the shock-absorbing and load bearing qualities of real cartilage. It can be formulated to exhibit different properties, and they are now hoping to use it to develop implants for replacing damaged cartilage discs between vertebrae.
They believe it also has the potential to encourage cartilage cells to grow in knees, which has previously not been possible with conventional methods.
The bio-glass consists of silica and a plastic or polymer called polycaprolactone. It displays cartilage-like properties including being flexible, strong, durable and resilient. It can be made in a biodegradable ink form, enabling the researchers to 3D print it into structures that encourage cartilage cells in the knee to form and grow – a process that they have demonstrated in test tubes.
Human articular cartilage defects can be treated with nasal septum cells.
Researchers at the University and the University Hospital of Basel report that cells taken from the nasal septum are able to adapt to the environment of the knee joint and can thus repair articular cartilage defects. The nasal cartilage cells’ ability to self-renew and adapt to the joint environment is associated with the expression of so-called HOX genes. The scientific journal Science Translational Medicine has published the research results together with the report of the first treated patients.
Cartilage lesions in joints often appear in older people as a result of degenerative processes. However, they also regularly affect younger people after injuries and accidents. Such defects are difficult to repair and often require complicated surgery and long rehabilitation times. A new treatment option has now been presented by a research team lead by Prof. Ivan Martin, professor for tissue engineering, and Prof. Marcel Jakob, Head of Traumatology, from the Department of Biomedicine at the University and the University Hospital of Basel: Nasal cartilage cells can replace cartilage cells in joints.
Cartilage cells from the nasal septum (nasal chondrocytes) have a distinct capacity to generate a new cartilage tissue after their expansion in culture. In an ongoing clinical study, the researchers have so far taken small biopsies (6 millimeters in diameter) from the nasal septum from seven out of 25 patients below the age of 55 years and then isolated the cartilage cells. They cultured and multiplied the cells and then applied them to a scaffold in order to engineer a cartilage graft the size of 30 x 40 millimeters. A few weeks later they removed the damaged cartilage tissue of the patients’ knees and replaced it with the engineered and tailored tissue from the nose. In a previous clinical study conducted in cooperation with plastic surgeons and using the same method, the researchers from Basel recently already successfully reconstructed nasal wings affected by tumors.
Scientists at the University of Basel report first ever successful nose reconstruction surgery using cartilage grown in the laboratory.
Cartilage cells were extracted from the patient’s nasal septum, multiplied and expanded onto a collagen membrane. The so-called engineered cartilage was then shaped according to the defect and implanted. The results will be published in the current edition of the academic journal “The Lancet”.
A research team from the University of Basel in Switzerland has reported that nasal reconstruction using engineered cartilage is possible. They used a method called tissue engineering where cartilage is grown from patients’ own cells. This new technique was applied on five patients, aged 76 to 88 years, with severe defects on their nose after skin cancer surgery. One year after the reconstruction, all five patients were satisfied with their ability to breathe as well as with the cosmetic appearance of their nose. None of them reported any side effects.
Cells from the nasal septum
The type of non-melanoma skin cancer investigated in this study is most common on the nose, specifically the alar wing of the nose, because of its cumulative exposure to sunlight. To remove the tumor completely, surgeons often have to cut away parts of cartilage as well. Usually, grafts for reconstruction are taken from the nasal septum, the ear or the ribs and used to functionally reconstruct the nose. However, this procedure is very invasive, painful and can, due to the additional surgery, lead to complications at the site of the excision.
Together with colleagues from the University Hospital, the research team from the Department of Biomedicine at the University of Basel has now developed an alternative approach using engineered cartilage tissue grown from cells of the patients’ nasal septum. They extracted a small biopsy, isolated the cartilage cells (chondrocytes) and multiplied them. The expanded cells were seeded onto a collagen membrane and cultured for two additional weeks, generating cartilage 40 times the size of the original biopsy. The engineered grafts were then shaped according to the defect on the nostril and implanted.
New possibilities for facial reconstruction
According to Ivan Martin, Professor for Tissue Engineering at the Department of Biomedicine at the University and University Hospital of Basel, “The engineered cartilage had clinical results comparable to the current standard surgery. This new technique could help the body to accept the new tissue better and to improve the stability and functionality of the nostril. Our success is based on the long-standing, effective integration in Basel between our experimental group at the Department of Biomedicine and the surgical disciplines at the University Hospital. The method opens the way to using engineered cartilage for more challenging reconstructions in facial surgery such as the complete nose, eyelid or ear.”
The same engineered grafts are currently being tested in a parallel study for articular cartilage repair in the knee. Despite the optimistic perspectives, the use of these procedures in the clinical practice is still rather distant. “We need rigorous assessment of efficacy on larger cohorts of patients and the development of business models and manufacturing paradigms that will guarantee cost-effectiveness”, says Martin.