Introduction. The COL5A1 gene encodes for the α1 chain of type V collagen, a minor fibrillar collagen that is an important regulator of collagen fibrillogenesis. Several polymorphisms, including rs12722 (C/T), within the 3′-UTR of COL5A1 are associated with chronic Achilles tendinopathy and other musculoskeletal soft tissue injuries as well as exercise-related phenotypes. It is hypothesised that polymorphisms within the 3′-UTR regulate the amount of the α1(V) chain synthesised and type V collagen production. This in turn influencing the mechanical properties of tendons and other musculoskeletal soft tissues. In our laboratories, two major functional forms, namely the T- and C-allelic forms of the COL5A1 3′-UTR, were identified and associated predominately with severe chronic Achilles tendinopathy and healthy asymptomatic control individuals, respectively. Materials and Methods. To further investigate the functional differences between the two major 3′-UTR functional forms as well as to start mapping the regions which are responsible for the tendinopathic phenotype, skin biopsies from donors having a known genotype at rs12722 and primary fibroblast cell lines were established in order to quantify COL5A1 and COL1A1 expression levels in a pilot study. Lastly, in preliminary RNA EMSAs, biotinylated C- and T-allelic RNA probes for a specific 57bp functional region within the 3′-UTR were incubated with either fibroblast nuclear or cytoplasmic protein extracts to investigate putative distinguishing RNA:RBP complex formation. Results. An overall higher relative mRNA expression of both COL5A1 (p<0.001) and COL1A1 (p=0.0015) were observed in primary skin fibroblasts from donors having a rs12722 TT genotype compared to donors with a CC genotype. A unique RNA:RBP complex was also identified with the C-allelic probe. Discussion. These novel results have important implications for our understanding of the proposed role of type V collagen in the aetiology of tendon and other musculoskeletal soft tissue injuries, as well as, other exercise-related phenotypes

Chronic Achilles tendinopathy is characterised by sub-acute inflammation with pro-inflammatory type 1 macrophages (M1), tissue degeneration and consequent partial or total tendon injury. Control of the inflammatory response and M1-to-M2 macrophage polarisation can favour tendon healing both directly and indirectly, by allowing for the regenerative process driven by local mesenchymal stem cells. Ten patients (3 females and 7 males aged between 32 and 71 years old) with partial Achilles tendon injury were treated with injections of autologous peripheral blood mononuclear cells (PB-MNCs). The cell concentrate was obtained from 100-120 cc of each patient's blood with a selective point-of-care filtration system. PB-MNCs remained trapped in the filter and were injected immediately after sampling. Around 60% of the PB-MNC concentrate was injected directly into the injured area, while the remaining 40% was injected in smaller amounts into the surrounding parts of the Achilles tendon affected by tendinosis. All patients were evaluated both clinically with the help of the American Orthopaedic Foot & Ankle Society (AOFAS) scale, and radiologically (MRI examination) at baseline and 2 months after the PB-MNC injection. A clinical reassessment with the AOFAS scale was also performed 6 months after the intervention. The rehabilitation protocol implied full weight-bearing walking immediately after the procedure, light physical activity 3-4 days after the injection, and physiotherapist-assisted stretching exercises and eccentric training. In all patients, functional and radiological signs of tendon healing processes were detected as early as 2 months after a single treatment and the AOFAS scale rose from the initial mean value of 37.5 (baseline) to 85.4 (6 months). Our preliminary results indicate that regenerative therapies with PB-MNCs can prove useful for partial Achilles tendon injuries as a valid alternative to surgical options, especially when other conservative approaches have failed. Advantages of this therapy include rapid execution, no need for an operating theatre, easy reproducibility, quick recovery and good tolerability regardless of the patient's age (the procedure is not to be performed in subjects who are below 18 years old). Further studies on the topic are recommended to confirm these observations

Summary Statement. ASTM therapy is commonly used to treat Achilles tendinopaty. However, there was no report to evaluate the biomechanical effects, especially the dynamic viscoelasticity. We have shown that ASTM treatment was biomechanically useful for chronic Achilles tendinopathy in an animal model. Introduction. Achilles tendinopathy is a common chronic overuse injury. Because Achilles tendon overuse injury takes place in sports and there has been a general increase in the popularity of sports activities, the number and incidence of Achilles tendon overuse injury has increased. Augmented Soft Tissue Mobilization (ASTM) therapy is a modification of traditional soft tissue mobilization and has been used to treat a variety of musculoskeletal disorders. ASTM therapy is thought to promote collagen fiber realignment and hasten tendon repair. It might also change the biomechanical behavior of the injured tendon, especially the dynamic viscoelasticity. The purpose of this study is to evaluate the effect of ASTM therapy in a rabbit model of Achilles tendinopathy by quantifying dynamic biomechanical properties and histologic features. Patients & Methods. The hind limbs of 12 rabbits were used, and 24 Achilles tendons were injected with collagenase to produce tendon injury. One hind limb of each animal was then randomly allocated to receive ASTM therapy, while the other received no treatment and served as a control. ASTM was performed on the Achilles tendon for 3 minutes on postoperative days 21, 24, 28, 31, 35, and 38. The Achilles tendons were harvested 10 days after the last treatment. Specimens were examined with dynamic viscoelasticity and light microscopy. Results. The mean±SD cross-sectional area for the treated and untreated tendons was 12.30±5.47 mm. 2. and 9.57±8.36 mm. 2. , respectively. The difference between the treated and untreated tendons was statistically significant (P<.01). At all dynamic loading frequencies, the storage modulus in the untreated tendons tended to be higher than that in the treated tendons. At 0.1 Hz and 10 Hz, in the untreated tendons was significantly higher than that in the treated tendons (P=.05). The loss modulus was significantly lower in the treated tendons than in the untreated tendons (P<.05). There was no significant difference in tan δ between the treated and untreated tendons. HE stain showed that the untreated tendon fiber was wavy and kinking and displayed a disordered collagen arrangement. In contrast, the tendon fiber was well aligned in the treated tendons. In the immunohistochemically stained specimens, the type III collagen showed higher color intensity in the untreated tendons than in the treated tendons. Discussion/Conclusion. We have shown that ASTM was a biomechanically useful treatment for chronic Achilles tendinopathy. Biomechanical and histologic data showed the treated Achilles tendons had better biomechanical function and histologic outcomes than the untreated tendons