Growth kinetics and integrin expression of fibroblasts infiltrating devitalised patellar tendons are different from those of intrinsic fibroblasts

Abstract

We compared the biological characteristics of extrinsic fibroblasts infiltrating the patellar tendon with those of normal, intrinsic fibroblasts in the normal tendon in vitro. Infiltrative fibroblasts were isolated from the patellar tendons of rabbits six weeks after an in situ freeze-thaw treatment which killed the intrinsic fibroblasts. These intrinsic cells were also isolated from the patellar tendons of rabbits which had not been so treated. Proliferation and invasive migration into the patellar tendon was significantly slower for infiltrative fibroblasts than for normal tendon fibroblasts. Flow-cytometric analysis indicated that expression of alpha5beta1 integrin at the cell surface was significantly lower in infiltrative fibroblasts than in normal tendon fibroblasts. The findings suggest that cellular proliferation and invasive migration of fibroblasts into the patellar tendon after necrosis are inferior to those of the normal fibroblasts. The inferior intrinsic properties of infiltrative fibroblasts may contribute to a slow remodelling process in the grafted tendon after ligament reconstruction.

Antibody neutralization of TGF-β enhances the deterioration of collagen fascicles in a tissue-cultured tendon matrix with ex vivo fibroblast infiltration

“…In each rabbit, fibroblasts were obtained from the right patellar tendon using an explant culture technique, and the left patellar tendon underwent multiple freeze/thaw treatment with liquid nitrogen to obtain an acellular tendon matrix (King et al, 1995;Ikema et al, 2005). Each acellular tendon matrix was paired with cultured fibroblasts derived from the patellar tendon in the opposite knee of the same animal.…”

“…We devitalized these patellar tendons using multiple freeze/thaw treatment (King et al, 1995;Ikema et al, 2005). Briefly, the patellar tendons were immersed in liquid nitrogen for 1 minute and then thawed in saline solution at 37°C.…”

“…The acellular tendon matrix be regarded as a type of collagenous scaffold. Recently, the authors developed a method of inducing cultured fibroblasts to infiltrate the repetitively frozen-thawed tendon matrix in an ex vivo state (Ikema et al, 2005). The tissue-cultured tendon matrix infiltrated with cultured fibroblasts can be regarded as an ideal tissue-engineered tendon model.…”

Application of Growth Factors for Enhancement of Mechanical Strength of Grafted Tendon Following Anterior Cruciate Ligament Reconstruction

“…To understand the remodeling of the tendon autograft in ligament reconstruction, it is necessary to clarify differences in biological characteristics between the infiltrative and intrinsic fibroblasts. We have compared the biological characteristics of infiltrative fibroblasts into the patellar tendon after fibroblast necrosis using an in situ freeze-thaw procedure to normal patellar tendon fibroblasts (Ikema, 2005;Tohyama, 2007). The in situ frozen-thawed patellar tendon simulates ligament reconstruction with the patellar tendon graft under ideal condition.…”

“…2) (Ikema, 2005;Tohyama, 2007). The slow remodeling process in the tendon graft may be attributed to these inferior potentials of infiltrative fibroblasts.…”