Additive manufactured, highly resilient, elastic, and biodegradable poly(ester)urethane scaffolds with chondroinductive properties for cartilage tissue engineering.

Articular cartilage was thought to be one of the first tissues to be successfully engineered. Despite the avascular and non-innervated nature of the tissue, the cells within articular cartilage - chondrocytes - account for a complex phenotype that is difficult to be maintained in vitro. The use of bone marrow-derived stromal cells (BMSCs) has emerged as a potential solution to this issue. Differentiation of BMSCs toward stable and non-hypertrophic chondrogenic phenotypes has also proved to be challenging. Moreover, hyaline cartilage presents a set of mechanical properties - relatively high Young's modulus, elasticity, and resilience - that are difficult to reproduce. Here, we report on the use of additive manufactured biodegradable poly(ester)urethane (PEU) scaffolds of two different structures (500 µm pore size and 90° or 60° deposition angle) that can support the loads applied onto the knee while being highly resilient, with a permanent deformation lower than 1% after 10 compression-relaxation cycles. Moreover, these scaffolds appear to promote BMSC differentiation, as shown by the deposition of glycosaminoglycans and collagens (in particular collagen II). At gene level, BMSCs showed an upregulation of chondrogenic markers, such as collagen II and the Sox trio, to higher or similar levels than that of traditional pellet cultures, with a collagen II/collagen I relative expression of 2-3, depending on the structure of the scaffold. Moreover, scaffolds with different pore architectures influenced the differentiation process and the final BMSC phenotype. These data suggest that additive manufactured PEU scaffolds could be good candidates for cartilage tissue regeneration in combination with microfracture interventions.

Juvenile arthritis in Turner's syndrome: a multicenter study.

OBJECTIVE: Turner's syndrome (TS) is a disorder associated with characteristic defects in the X chromosome. Autoimmune conditions such as thyroiditis, inflammatory bowel diseases and diabetes have been described in association with TS. METHODS: We have studied the association between TS and juvenile arthritis (JA) by using a survey in which 28 pediatric rheumatology centers (15 in the USA, 10 in Europe, and 3 in Canada) participated. RESULTS: Eighteen cases of TS in a population of approximately 15,000 JRA patients have been found. Two different patterns of arthritis were present: polyarticular (7) and oligoarticular (11). Children with polyarticular disease had early onset, seronegative, progressively deforming arthritis and growth retardation. Those with oligoarticular arthritis had a benign course and were ANA+ (8/11). The oligoarticular children had varying karyotypes whereas almost all of the polyarthritic patients shared the same 45X0 karyotype (6/7). The light and electron microscopic studies of synovium performed in two patients showed chronic inflammation and hyperplasia of the synovial lining cells, vascular proliferation and infiltration with lymphocytes, plasma cells and mononuclear phagocytes. CONCLUSION: Juvenile arthritis is a new autoimmune condition association with Turner's syndrome. The prevalence seems to be at least six times greater than would be expected if the two conditions were only randomly associated. This is the first description of the synovium in Turner's syndrome; no differences from other forms of juvenile rheumatoid arthritis were found.

Monoarticular juvenile chronic arthritis of the shoulder. Report of a case and review of the literature.

In 20% of the cases Juvenile Chronic Arthritis (JCA) has a monoarticular onset. Usually the inflammatory process spreads out to other joints with pauciarticular or polyarticular course. Very rarely the disease persists in one joint only and this is in about 70% of the cases, the knee. We describe a case of Monoarticular JCA with isolate and persistent involvement of the shoulder never reported in the literature. The clinical, pathologic features and different diagnoses are discussed.