Storage conditions do not have detrimental effect on allograft collagen or scaffold performance

Effect of type 2 diabetes mellitus on the microstructural, compositional and mechanical properties of cartilages

BACKGROUND

Osteoarthritis (OA) is a chronic and complicated degenerative disorder of joints, including several phenotypes. Type 2 diabetes mellitus (T2DM) is one of the major causes of OA. However, few studies on the mechanical behavior of diabetic cartilages have been conducted.

METHODS

This study evaluated the microstructural, compositional, and mechanical properties of healthy and diabetic rat cartilages using scanning electronic microscopy, X-ray energy spectroscopy, histology staining, and microindentation tests.

RESULTS

Our results indicated that the diabetic cartilages had a significantly higher elastic modulus and similar permeability (95%CI: 3.72-8.56 MPa and 3.16×10-6-1.83×10-5 mm4/N·s) compared to the healthy cartilages (95%CI: 0.741-3.58 MPa and 3.15×10-6-1.14×10-5 mm4/N·s). Their stress relaxation behaviors were similar regardless of the loading rate except for the stretching parameter under the fast loading. Furthermore, the stress relaxation behaviors of the diabetic cartilages were significantly affected by the loading rate, especially the equilibrium force ratio and time constant. These mechanical outcomes could be attributed to the increase of fibril diameters and calcium aggregation in the cartilage.

CONCLUSIONS

This study deepens our understanding of how T2DM might facilitate OA in cartilages, which could contribute to the development of more scientific diagnosis and therapies for patients with diabetes.

Safety of intra-articular use of atelocollagen for enhanced tissue repair

Collagen is an important biomaterial in intra-articular tissue engineering, but there are unanswered questions about its safety. We hypothesize that the addition of type-I-collagen for primary repair of the Anterior Cruciate Ligament (ACL) might result in a local and systemic reaction in a porcine model after 15 weeks as demonstrated by joint effusion, synovial thickening, elevated intraarticular and systemic leukocyte counts. Further, this reaction might be aggravated by the addition of a platelet concentrate. Eighteen porcine ACLs were transected and repaired with either sutures (n=6), a collagen sponge (n=6), or a collagen-platelet-composite (CPC; n=6). Twelve intact contralateral knees served as controls (n=12). No significant synovial thickening or joint effusion was seen in the collagen-treated knees. Synovial fluid leukocyte counts showed no significant differences between surgically treated and intact knees, and no differences were seen in leukocyte counts of the peripheral blood. The addition of a platelet concentrate to the knee joint resulted in lower serum levels of IL-1β, but serum levels of TNF-α were not significantly different between groups. In conclusion, the presence of collagen, with or without added platelets, did not increase the local or systemic inflammatory reactions following surgery, suggesting that Type I collagen is safe to use in the knee joint.