Tendinopathy in diabetes mellitus patients-Epidemiology, pathogenesis, and management

The repair of injured tendons remains a great challenge, largely owing to a lack of in-depth characterization of tendon cells and their precursors. We show that human and mouse tendons harbor a unique cell population, termed tendon stem/progenitor cells (TSPCs), that has universal stem cell characteristics such as clonogenicity, multipotency and self-renewal capacity. The isolated TSPCs could regenerate tendon-like tissues after extended expansion in vitro and transplantation in vivo. Moreover, we show that TSPCs reside within a unique niche predominantly comprised of an extracellular matrix, and we identify biglycan (Bgn) and fibromodulin (Fmod) as two critical components that organize this niche. Depletion of Bgn and Fmod affects the differentiation of TSPCs by modulating bone morphogenetic protein signaling and impairs tendon formation in vivo. Our results, while offering new insights into the biology of tendon cells, may assist in future strategies to treat tendon diseases.

Few evidence-based treatment guidelines for tendinopathy exist. We undertook a systematic review of randomised trials to establish clinical efficacy and risk of adverse events for treatment by injection. We searched eight databases without language, publication, or date restrictions. We included randomised trials assessing efficacy of one or more peritendinous injections with placebo or non-surgical interventions for tendinopathy, scoring more than 50% on the modified physiotherapy evidence database scale. We undertook meta-analyses with a random-effects model, and estimated relative risk and standardised mean differences (SMDs). The primary outcome of clinical efficacy was protocol-defined pain score in the short term (4 weeks, range 0-12), intermediate term (26 weeks, 13-26), or long term (52 weeks, ≥52). Adverse events were also reported. 3824 trials were identified and 41 met inclusion criteria, providing data for 2672 participants. We showed consistent findings between many high-quality randomised controlled trials that corticosteroid injections reduced pain in the short term compared with other interventions, but this effect was reversed at intermediate and long terms. For example, in pooled analysis of treatment for lateral epicondylalgia, corticosteroid injection had a large effect (defined as SMD>0·8) on reduction of pain compared with no intervention in the short term (SMD 1·44, 95% CI 1·17-1·71, p<0·0001), but no intervention was favoured at intermediate term (-0·40, -0·67 to -0·14, p<0·003) and long term (-0·31, -0·61 to -0·01, p=0·05). Short-term efficacy of corticosteroid injections for rotator-cuff tendinopathy is not clear. Of 991 participants who received corticosteroid injections in studies that reported adverse events, only one (0·1%) had a serious adverse event (tendon rupture). By comparison with placebo, reductions in pain were reported after injections of sodium hyaluronate (short [3·91, 3·54-4·28, p<0·0001], intermediate [2·89, 2·58-3·20, p<0·0001], and long [3·91, 3·55-4·28, p<0·0001] terms), botulinum toxin (short term [1·23, 0·67-1·78, p<0·0001]), and prolotherapy (intermediate term [2·62, 1·36-3·88, p<0·0001]) for treatment of lateral epicondylalgia. Lauromacrogol (polidocanol), aprotinin, and platelet-rich plasma were not more efficacious than was placebo for Achilles tendinopathy, while prolotherapy was not more effective than was eccentric exercise. Despite the effectiveness of corticosteroid injections in the short term, non-corticosteroid injections might be of benefit for long-term treatment of lateral epicondylalgia. However, response to injection should not be generalised because of variation in effect between sites of tendinopathy. None. Copyright © 2010 Elsevier Ltd. All rights reserved.

Recent studies revealed a close connection between adipose tissue, adipokines and articular degenerative inflammatory diseases such as rheumatoid arthritis (RA) and osteoarthritis (OA). The goal of this work was to investigate the activity of adiponectin in human and murine chondrocytes and to study its functional role in the modulation of nitric oxide synthase type II (NOS2). For completeness, interleukin (IL)-6, IL-1beta, matrix metalloproteinase (MMP)-2, MMP-3, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, prostaglandin E2 (PGE2), leukotriene B4 (LTB4), tumor necrosis factor alpha (TNF)-alpha and monocyte chemoattractant protein-1 (MCP-1) accumulation have been evaluated in adiponectin-stimulated chondrocytes cell culture supernatants. Murine ATDC5 cell line, C28/I2, C20A4, TC28a2 human immortalized chondrocytes, and human cultured chondrocytes were used. Nitrite accumulation was determined by Griess reaction. Adiponectin receptors (AdipoRs) expression was evaluated by immunofluorescence microscopy and confirmed by reverse transcriptase-polymerase chain reaction. NOS2 expression was evaluated by Western blot analysis whereas cytokines, prostanoids and metalloproteinases production was evaluated by specific enzyme-linked immunosorbent assays. Human and murine chondrocytes express functional AdipoRs. Adiponectin induces NOS2. This effect is inhibited by aminoguanidine, dexamethasone and by a selective inhibitor of phosphatidylinositol 3-kinase. In addition, adiponectin is able to increase IL-6, MMP-3, MMP-9 and MCP-1 by murine cultured chondrocytes whereas it was unable to modulate TNF-alpha, IL-1beta, MMP-2, TIMP-1, PGE2 and LTB4 release. These results bind more closely the interactions between fat-derived adipokines and articular inflammatory diseases, and suggest that adiponectin is a novel key element in the maintenance of cartilage homeostasis which might be considered as a potential therapeutical target in joint degenerative diseases.