VEGF Expression in Patellar Tendinopathy: A Preliminary Study

Abstract

Vascular function and angiogenesis are regulated by vascular endothelial growth factor-A (VEGF). The purpose of this preliminary study was to address the following questions: Is VEGF expression in the patellar tendon more prevalent in patients with patellar tendinopathy than in individuals with normal, pain-free patellar tendons? Which cell populations express VEGF in normal and tendinopathic tendon? Is there a difference in symptom duration between VEGF+ and VEGF- tendons? We collected patellar tendon tissue from 22 patients undergoing open débridement of the patellar tendon and from 10 patients undergoing intramedullary nailing of the tibia. VEGF expression was assessed immunohistochemically. Relevant inflammatory and repair cell types were immunolabeled. VEGF expression was absent from control tendons, but was present in a subset of patients with histopathological evidence of angiofibroblastic tendinosis. VEGF was expressed in the intimal layer of tendon vessels, but was absent in other cell types. Patients demonstrating VEGF expression in the patellar tendon had a shorter symptom duration (12 +/- 7.8 months) than patients with no detectable VEGF (32.8 +/- 23.5 months). VEGF may contribute to the vascular hyperplasia that is a cardinal feature of symptomatic tendinosis, particularly in cases with more recent onset.

Uphill running improves rat Achilles tendon tissue mechanical properties and alters gene expression without inducing pathological changes

“…Since we found unchanged type I collagen expression, decreased MMP-2 expression, and a trend toward an increased MMP-3 expression (P ϭ 0.07), it seems clear that the gene expression profile of the rat Achilles tendons subjected to 12 wk of running does not fit well with that of a tendinopathic tendon. In further support of this, we found decreased levels of VEGF and proteoglycan mRNA (fibromodulin and biglycan), which are thought to be elevated with tendinopathy (4,12,13,36,38). These mRNA results serve to underline the more fundamental finding of unchanged tissue histology, which clearly indicates that the training model does not induce Achilles tendinopathy.…”

Experimental Diabetes Induces Structural, Inflammatory and Vascular Changes of Achilles Tendons

“…In addition, an increase of microvascular density, proliferation of endothelial cells and an increase in perivascular mast cells in tendinopathies have been confirmed [24], [25], [26] which demonstrates a strong link between vascular hyperplasia and tendon dysfunction caused by overuse or by microtrauma.…”

Impaired biomechanical properties correlate with neoangiogenesis as well as VEGF and MMP‐3 expression during rat patellar tendon healing

“…Tendon ruptures, which occur without adequate trauma, are called ''spontaneous rupture.'' 2 The etiology and pathogenesis to these conditions are largely unknown and treatment remains difficult. Many studies have shown that degenerative tendon diseases preferential develop in hypovascular regions.…”