Differential cross-linking and radio-protective effects of genipin on mature bovine and human patella tendons

• DOI: 10.1007/s10561-012-9295-3
• Publication Date: 2012-02-20T11:01:18Z
• Authors: Kenneth W. Ng; Florian Wanivenhaus; Tony Chen; Valarian D. Abrams; Peter A. Torzilli; Russell F. Warren; Suzanne A. Maher
• Keywords: Male; Time Factors; Cell Death; Radiation-Protective Agents; Middle Aged; 03 medical and health sciences; Cross-Linking Reagents; 0302 clinical medicine; Patellar Ligament; Tensile Strength; Animals; Humans; Cattle; Female; Iridoids

Gamma irradiation is a proven sterilization method, but is not widely used on allografts for anterior cruciate ligament reconstruction (e.g., patella tendon) due to radiation-induced decreases in mechanical strength. Addressing this drawback would improve the safety and supply of allografts to meet current and future demand. It was hypothesized that genipin-induced collagen cross-linking would increase the tensile modulus of patella tendon tissue such that 5 MRad gamma irradiation would not reduce the tissue mechanical strength below the original untreated values. Optimized genipin treatment increased the tensile modulus of bovine tendons by ~2.4-fold. After irradiation, genipin treated tissue did not significantly differ from native tissue, proving the hypothesis. Optimized genipin treatment of human tendons increased the tensile modulus by ~1.3-fold. After irradiation, both control and genipin-treated tissues possessed ~50-60% of their native tendon modulus, disproving the hypothesis. These results highlight possible age- and species- dependent effects of genipin cross-linking on tendon tissue. Cross-linking of human allografts may be beneficial only in younger donor tissues. Future research is warranted to better understand the mechanisms and applications of collagen cross-linking for clinical use.