Short-duration enzymatic treatment promotes integration of a cartilage graft in a defect.

OBJECTIVES: Surgical manipulation of cartilage tissue is associated with chondrocyte death in the wound edges that hinders integration. The objective of this study was to evaluate the effect of a short course of treatment of a cartilage graft with a combination of hyaluronidase and collagenase on chondrocyte density and integrative capacity. METHODS: Cartilage explants were treated with enzymes for various time periods and at various concentrations. A central core was punched out of a larger explant, treated with enzymes, reimplanted, and placed subcutaneously in athymic mice. The number of chondrocytes in the wound edges was counted, and the integrative capacity of the grafts was evaluated by histology. RESULTS: Treatment with collagenase for 48 hours led to a significant increase in the number of vital chondrocytes and restored it to normal after 14 days of culture. Treatment with hyaluronidase and collagenase for 48 hours further increased chondrocyte densities to supranormal values. Shortening the treatment to 1 hour restored the chondrocyte density to normal after 14 days of culture. In vivo integration experiments showed increased chondrocyte densities in treated wound edges and extracellular matrix fibers crossing over from enzyme-treated parts to untreated parts. CONCLUSIONS: Short-duration treatment of a cartilage graft with a combination of hyaluronidase and collagenase increases cell density at wound edges and promotes integrative repair.

Increased risk of breast cancer development after diagnosis of salivary gland tumour.

The aim of this study was to evaluate whether patients with salivary gland tumours are at increased risk of developing breast cancer. A retrospective cohort study was performed. Female patients (n = 439) with a salivary gland tumour (major and minor) were included. The diagnosis was confirmed histologically. The median follow-up was 5.4 years. Fifteen patients out of 439 with a salivary gland tumour subsequently developed breast cancer, with a mean time interval of 64 months. On the basis of incidence rates in the general population 5.93 breast cancers would be expected. The standardised incidence ratio (SIR) was 2.5 (95% confidence interval: 1.4-4.2; P = 0.003). Increased SIRs were also observed for other solid malignancies, but the numbers were small (n < 5). It is concluded that female patients with a salivary gland tumour have a 2.5 times increased risk of developing breast cancer. Breast screening of these patients is therefore recommended.

Improved cartilage integration and interfacial strength after enzymatic treatment in a cartilage transplantation model.

The objective of the present study was to investigate whether treatment of articular cartilage with hyaluronidase and collagenase enhances histological and mechanical integration of a cartilage graft into a defect. Discs of 3 mm diameter were taken from 8-mm diameter bovine cartilage explants. Both discs and annulus were either treated for 24 hours with 0.1% hyaluronidase followed by 24 hours with 10 U/ml collagenase or left untreated (controls). Discs and annulus were reassembled and implanted subcutaneously in nude mice for 5 weeks. Integration of disc with surrounding cartilage was assessed histologically and tested biomechanically by performing a push-out test. After 5 weeks a significant increase in viable cell counts was seen in wound edges of the enzyme-treated group as compared with controls. Furthermore, matrix integration (expressed as a percentage of the total interface length that was connected; mean +/- standard error) was 83 +/- 15% in the treated samples versus 44 +/- 40% in the untreated controls. In the enzyme-treated group only, picro-Sirius Red staining revealed collagen crossing the interface perpendicular to the wound surface. Immunohistochemical analyses demonstrated that the interface tissue contained cartilage-specific collagen type II. Collagen type I was found only in a small region of fibrous tissue at the level of the superficial layer, and collagen type III was completely absent in both groups. A significant difference in interfacial strength was found using the push-out test: 1.32 +/- 0.15 MPa in the enzyme-treated group versus 0.84 +/- 0.14 MPa in the untreated controls. The study shows that enzyme treatment of cartilage wounds increases histological integration and improves biomechanical bonding strength. Enzymatic treatment may represent a promising addition to current techniques for articular cartilage repair.