Increased versican content is associated with tendinosis pathology in the patellar tendon of athletes with jumper's knee

Abstract

Expansion of the extracellular matrix is a prominent but poorly characterized feature of tendinosis. The present study aimed to characterize the extent and distribution of the large aggregating proteoglycan versican in patients with patellar tendinosis. We obtained tendon from tendinopathy patients undergoing debridement of the patellar tendon and from controls undergoing intramedullary tibial nailing. Versican content was investigated by Western blotting and immunohistochemistry. Microvessel thickness and density were determined using computerassisted image analysis. Markers for smooth muscle (α-SMA), endothelial cells (CD31) and proliferating cells (Ki67) were examined immunohistochemically. Western blot analysis and immunohistochemical staining revealed elevated versican content in the proximal patellar tendon of tendinosis patients (p=0.042). Versican content was enriched in regions of fibrocartilage metaplasia and fibroblast proliferation, as well as in the perivascular matrix of proliferating microvessels and within the media and intima of arterioles. Microvessel density was higher in tendinosis tissue compared to control tissue. Versican deposition is a prominent feature of patellar tendinosis. Because this molecule is not only a component of normal fibrocartilagenous matrices, but is also implicated in a variety of soft tissue pathologies, future studies should further detail both pathological and adaptive roles of versican in tendons.

VEGF Expression in Patellar Tendinopathy: A Preliminary Study

“…Thus, both clinical and anatomic findings of regionally increased vascularity in tendinopathies have sparked interest in the possible role of angiogenesis in painful tendons [33,34]. We previously reported increased microvascular density, proliferation of endothelial and smooth muscle cells, and increased perivascular mast cell density in patient biopsies [22,38,39].…”

Neuropeptides in tendinopathy

“…An increased number of microvessels is a feature of tendinopathy --microvessel area may be increased up to 300% (12). Many of these vessels, especially the larger and more mature ones including arterioles, appear to have an accompanying nerve supply (11).…”

“…Whether the initiating event is due to collagen fibril and microvessel failure, or rather to load-induced responses in tenocytes, remains a subject of debate (6,7). However, the chronic pathological changes in the tendon and paratendon can be substantial and include an aberrant increase of microvessels and sensory nerves, abnormal quality and accelerated remodeling of the extracellular matrix, and increased local metabolism with excessive lactate production (8)(9)(10)(11)(12).…”

Relación entre estructura del pie y características del ligamento rotuliano en jugadores de voleibol

“…Se encuentra aumentado intratendón, en la matriz celular alrededor de los tenocitos y las células endoteliales 146 en casos de tendinosis rotuliana y específicamente en áreas de fibrocartílago, produciendo proliferación de fibroblastos en las zona de compresión y cizallamiento del tendón que en el caso del rotuliano corresponden con el fascículo profundo (Figura 12 zona 1) y alrededor de los neovasos intratendinosos 147 (Figura 12 zona 2). La alteración del perfil de los PG conduce a una aumento en el contenido en agua en la zona del tendón debido a la propia naturaleza hidrófila de estos GAG's asociados con agrecano y versicano 147,148 en determinadas zonas. Este incremento del contenido en GAG y PG's provoca una aumento del grosor del tendón quizá debido a una mayor repuesta 57 del tendón a la sobrecarga como propia protección frente a una rotura y de aquí una debilidad de este 148,149 .…”

“…Este incremento del contenido en GAG y PG's provoca una aumento del grosor del tendón quizá debido a una mayor repuesta 57 del tendón a la sobrecarga como propia protección frente a una rotura y de aquí una debilidad de este 148,149 . El exceso de versicano provoca un aumento del volumen de la matriz extracelular en zonas de tendinosis patelar asociado a regiones de fibrocartílago, hipervascularidad e hipercelularidad 147 .…”