Blocking fibrotic signaling in fibroblasts from patients with carpal tunnel syndrome

Comprehensive gene expression analysis using RNA sequencing between male and female patients with idiopathic carpal tunnel syndrome

Idiopathic carpal tunnel syndrome is the most common entrapment neuropathy in hand surgery, and it is characterized by Noninflammatory fibrosis of subsynovial connective tissues. The prevalence and incidence differ between male and female individuals, and the mechanism underlying this difference remains largely unclear. In the present study, we collected subsynovial connective tissues from six male and six female patients diagnosed with idiopathic carpal tunnel syndrome during surgery. We performed a comprehensive gene expression analysis using RNA sequencing to compare the gene expression profiles between male and female patients with idiopathic carpal tunnel syndrome. We identified 26 genes with significantly different expressions between male and female patients, in which POSTN, COL1A1, and COL3A1, which are involved in extracellular matrix organization, and IGF1, an important fibrotic factor, were significantly upregulated in male patients. Immunohistochemistry confirmed the expression of proteins encoded by these genes in tissues, and male patients tended to show increased POSTN expression. Our results indicate that fibrosis of subsynovial connective tissues is induced by different mechanisms in male and female patients, and genes involved in extracellular matrix organization, especially POSTN, might be important factors in male patients. This study provides insight into the pathogenesis of idiopathic carpal syndrome and might contribute to the development of new treatment strategies.

Genetic effects of sequence-conserved enhancer-like elements on human complex traits

BACKGROUND

The vast majority of findings from human genome-wide association studies (GWAS) map to non-coding sequences, complicating their mechanistic interpretations and clinical translations. Non-coding sequences that are evolutionarily conserved and biochemically active could offer clues to the mechanisms underpinning GWAS discoveries. However, genetic effects of such sequences have not been systematically examined across a wide range of human tissues and traits, hampering progress to fully understand regulatory causes of human complex traits.

RESULTS

Here we develop a simple yet effective strategy to identify functional elements exhibiting high levels of human-mouse sequence conservation and enhancer-like biochemical activity, which scales well to 313 epigenomic datasets across 106 human tissues and cell types. Combined with 468 GWAS of European (EUR) and East Asian (EAS) ancestries, these elements show tissue-specific enrichments of heritability and causal variants for many traits, which are significantly stronger than enrichments based on enhancers without sequence conservation. These elements also help prioritize candidate genes that are functionally relevant to body mass index (BMI) and schizophrenia but were not reported in previous GWAS with large sample sizes.

CONCLUSIONS

Our findings provide a comprehensive assessment of how sequence-conserved enhancer-like elements affect complex traits in diverse tissues and demonstrate a generalizable strategy of integrating evolutionary and biochemical data to elucidate human disease genetics.

Impact of High Fat Diet and Sex in a Rabbit Model of Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is a common musculoskeletal disorder, characterized by fibrosis of the subsynovial connective tissue (SSCT) mediated by transforming growth factor beta (TGF-β). Risk factors for CTS include metabolic dysfunction and age. Additionally, the incidence of CTS is higher in women. In this study we hypothesized that a high-fat diet (HFD), a common driver of metabolic dysfunction, would promote SSCT fibrosis found in CTS and that this response would be sex dependent. To test this, we examined the effects of HFD and sex on SSCT fibrosis using our established rabbit model of CTS. Forty-eight (24 male, 24 female) adult rabbits were divided into four groups including HFD or standard diet with and without CTS induction. SSCT was collected for histological and gene expression analysis. HFD promoted SSCT thickening and upregulated profibrotic genes, including TGF-β. Fibrotic genes were differentially expressed in males and females. Interestingly while the prevalence of CTS is greater in women than in men, the converse is observed in the presence of metabolic dysfunction. This work recapitulates this clinical observation and begins to elucidate the sex-based differences found in SSCT fibrosis. This knowledge should drive further research and may lead to metabolic and sex specific therapeutic strategies for the treatment of patients with CTS.

The role of the anterior shoulder joint capsule in primary glenohumeral osteoarthritis

The pathogenesis of primary glenohumeral arthritis (GHOA) is mediated by a complex interaction between osseous anatomy and the surrounding soft tissues. Recently, there has been growing interest in characterizing the association between the anterior shoulder joint capsule and primary GHOA because of the potential for targeted treatment interventions. Emerging evidence has shown substantial synovitis, fibrosis, and mixed inflammatory cell infiltrate in the anterior capsule of osteoarthritic shoulders. In addition, increased thickening of the anterior shoulder joint capsule has been associated with greater posterior glenoid wear and humeral head subluxation. While these findings suggest that anterior capsular disease may play a causative role in the etiology and progression of eccentric GHOA, further studies are needed to support this association. The purpose of this article is to review the pathogenesis of primary GHOA, contextualize current hypotheses regarding the role of the anterior capsule in the disease process, and provide directions for future research.

Melanocortin therapies to resolve fibroblast-mediated diseases

Stromal cells have emerged as central drivers in multiple and diverse diseases, and consequently, as potential new cellular targets for the development of novel therapeutic strategies. In this review we revise the main roles of fibroblasts, not only as structural cells but also as players and regulators of immune responses. Important aspects like fibroblast heterogeneity, functional specialization and cellular plasticity are also discussed as well as the implications that these aspects may have in disease and in the design of novel therapeutics. An extensive revision of the actions of fibroblasts on different conditions uncovers the existence of numerous diseases in which this cell type plays a pathogenic role, either due to an exacerbation of their 'structural' side, or a dysregulation of their 'immune side'. In both cases, opportunities for the development of innovative therapeutic approaches exist. In this regard, here we revise the existing evidence pointing at the melanocortin pathway as a potential new strategy for the treatment and management of diseases mediated by aberrantly activated fibroblasts, including scleroderma or rheumatoid arthritis. This evidence derives from studies involving models of in vitro primary fibroblasts, in vivo models of disease as well as ongoing human clinical trials. Melanocortin drugs, which are pro-resolving mediators, have shown ability to reduce collagen deposition, activation of myofibroblasts, reduction of pro-inflammatory mediators and reduced scar formation. Here we also discuss existing challenges, both in approaching fibroblasts as therapeutic targets, and in the development of novel melanocortin drug candidates, that may help advance the field and deliver new medicines for the management of diseases with high medical needs.

Serum Levels of Inflammatory and Fibrotic Cytokines in Patients with Carpal Tunnel Syndrome and Hip Osteoarthritis

A certain percentage of carpal tunnel syndrome (CTS) is associated with inflammatory conditions. Osteoarthritis (OA) increases the risk of CTS, and both diseases are common in the general population. Moreover, OA and CTS are often present in the same patients. Since inflammation and fibrosis are found in both conditions, the question is whether circulating inflammatory cytokines and cytokines involved in fibrosis in OA and CTS patients could serve as indicators of coexisting CTS and OA pathology. This investigation was performed on 31 CTS patients, 29 hip OA patients, and 15 healthy volunteers. Blood samples were collected, and serum levels of TGF-β1, BMP-7, IL-1β, and TNFα were measured using the ELISA method. The statistical analysis was performed to reveal the most significant differences in the serum levels of these cytokines. Statistical significance was set at p-values ≤ 0.05. The serum level of TGF-β1 was the highest in CTS patients (16.36 pg/mL) and significantly different compared to OA and healthy control. Analysis of the cytokine serum level in the subdivided group revealed that serum levels of TGF-β1 and BMP-7 were significantly higher in CTS+/OA+ patients as well as BMP-7 in the OA+/CTS+ group. There was no significant difference in serum levels of the inflammatory cytokines TNFα and IL-1β among all groups. This study showed that in the end stage of CTS and OA, serum levels of inflammatory cytokines (IL1-β and TNFα) were not altered, while the serum levels of TGF-β1 and BMP-7 were significantly higher, especially in patients with coexisting OA and CTS. These findings suggest the possible values of TGF-β1 and BMP-7 as a predictive factor for the comorbidity of CTS and OA.

Oxygen-Ozone Therapy for Reducing Pro-Inflammatory Cytokines Serum Levels in Musculoskeletal and Temporomandibular Disorders: A Comprehensive Review

To date, the application of oxygen-ozone (O₂O₃) therapy has significantly increased in the common clinical practice in several pathological conditions. However, beyond the favorable clinical effects, the biochemical effects of O₂O₃ are still far from being understood. This comprehensive review aimed at investigating the state of the art about the effects of O₂O₃ therapy on pro-inflammatory cytokines serum levels as a modulator of oxidative stress in patients with musculoskeletal and temporomandibular disorders (TMD). The efficacy of O₂O₃ therapy could be related to the moderate oxidative stress modulation produced by the interaction of ozone with biological components. More in detail, O₂O₃ therapy is widely used as an adjuvant therapeutic option in several pathological conditions characterized by chronic inflammatory processes and immune overactivation. In this context, most musculoskeletal and temporomandibular disorders (TMD) share these two pathophysiological processes. Despite the paucity of in vivo studies, this comprehensive review suggests that O₂O₃ therapy might reduce serum levels of interleukin 6 in patients with TMD, low back pain, knee osteoarthritis and rheumatic diseases with a concrete and measurable interaction with the inflammatory pathway. However, to date, further studies are needed to clarify the effects of this promising therapy on inflammatory mediators and their clinical implications.

Administration of Purified Exosome Product in a Rat Sciatic Serve Reverse Autograft Model

BACKGROUND

The nerve autograft remains the gold standard when reconstructing peripheral nerve defects. However, although autograft repair can result in useful functional recovery, poor outcomes are common, and better treatments are needed. The purpose of this study was to evaluate the effect of purified exosome product on functional motor recovery and nerve-related gene expression in a rat sciatic nerve reverse autograft model.

METHODS

Ninety-six Sprague-Dawley rats were divided into three experimental groups. In each group, a unilateral 10-mm sciatic nerve defect was created. The excised nerve was reversed and used to reconstruct the defect. Group I animals received the reversed autograft alone, group II animals received the reversed autograft with fibrin glue, and group III animals received the reversed autograft with purified exosome product suspended in the fibrin glue. The animals were killed at 3 and 7 days and 12 and 16 weeks after surgery. Evaluation included compound muscle action potentials, isometric tetanic force, tibialis anterior muscle wet weight, nerve regeneration-related gene expression, and nerve histomorphometry.

RESULTS

At 16 weeks, isometric tetanic force was significantly better in group III (p = 0.03). The average axon diameter of the peroneal nerve was significantly larger in group III at both 12 and 16 weeks (p = 0.015 at 12 weeks; p < 0.01 at 16 weeks). GAP43 and S100b gene expression was significantly up-regulated by purified exosome product.

CONCLUSIONS

Local administration of purified exosome product demonstrated improved nerve regeneration profiles in the reverse sciatic nerve autograft rat model. Thus, purified exosome product may have beneficial effects on nerve regeneration, gene profiles, and motor outcomes.

Effect of a monocyte chemoattractant protein-1 synthesis inhibitor on fibroblasts from patients with carpal tunnel syndrome

BACKGROUND

Carpal Tunnel Syndrome (CTS) is an idiopathic fibrotic disorder. Fibrosis in the subsynovial connective tissues (SSCT) of CTS and many other fibrotic diseases is mediated by Transforming growth factor β (TGF-β). Recently monocyte chemoattractant protein-1 (MCP-1) a cytokine involved in cellular recruitment has been suggested to regulate TGF-β activity. It is related to the onset of diseases which are caused by fibrosis, such as idiopathic pulmonary fibrosis, renal fibrosis, and systemic scleroderma. In this study, we evaluated the effect of the MCP-1 synthesis inhibitor, Bindarit, on primary cultures of fibroblasts from the SSCT of five CTS patients.

METHODS

Fibroblasts were treated with Bindarit (10 μM, 50 μM, 100 μM, or 300 μM). Responses to inhibitors were evaluated by regulation of CTS fibrosis-associated genes, fibrosis gene array and Smad luciferase reporter assay. We also assessed the combination effect of Bindarit and SD208, a TGF-β receptor type 1 inhibitor on TGF-β signaling.

RESULTS

Collagen type III A1 (Col3), connective tissue growth factor (CTGF), and SERPINE1 expression were significantly down-regulated by Bindarit (300 μM) compared to vehicle control. In the fibrosis array, expression of inhibin beta E chain precursor (INHBE), beta actin (ACTB), endothelin 1 (EDN1) and hypoxanthine phosphoribosyltransferase 1 (HPRT1) were significantly down-regulated, and integrin beta-3 (ITGB3) was significantly up-regulated by Bindarit (300 μM). Smad signal transduction activation was significantly down-regulated by Bindarit (300 μM) and/or SD208 (1 μM) with TGF-β1 compared to vehicle control with TGF-β1.

CONCLUSIONS

These results suggest that Bindarit in combination with SD208 may be beneficial as medical therapy for the SSCT fibrosis associated with CTS.

Contracture and transient receptor potential channel upregulation in the anterior glenohumeral joint capsule of patients with end-stage osteoarthritis

BACKGROUND

During anatomic total shoulder arthroplasty (TSA) for primary glenohumeral osteoarthritis (GHOA), the anterior shoulder joint capsule (ASJC) is characterized grossly by contracture, synovitis, and fibrosis. In tissues that develop fibrosis, there is substantial cross-talk between macrophages, fibroblasts, and myofibroblasts, modulated by calcium signaling and transient receptor potential (TRP) channel signaling. The purpose of this study was to compare and characterize the degree of synovitis, inflammatory infiltrate, and TRP channel expression in ASJC harvested from shoulders with and without primary GHOA.

METHODS

The ASJC was resected from patients undergoing TSA for primary GHOA or other diagnoses and compared with ASJC from cadaveric donors with no history of shoulder pathology. ASJC was evaluated by immunohistochemistry to characterize synovial lining and capsular inflammatory cell infiltrate and fibrosis, and to evaluate for expression of TRPA1, TRPV1, and TRPV4, known to be involved in fibrosis in other tissues. Blinded sections were evaluated by 3 graders using a semiquantitative scale; then results were compared between diagnosis groups using nonparametric methods.

RESULTS

Compared with normal control, the ASJC in primary GHOA had significantly increased synovitis, fibrosis, mixed inflammatory cell infiltrate including multiple macrophages subsets, and upregulation of TRP channel expression.

CONCLUSION

These data support the clinical findings of ASJC and synovial fibrosis in primary GHOA, identify a mixed inflammatory response, and identify dysregulation of TRP channels in the synovium and joint capsule. Further studies will identify the role of synovial and capsular fibrosis early in the development of GHOA.

TGFβRI antagonist inhibits HIV-1 Nef-induced CC chemokine family ligand 2 (CCL2) in the brain and prevents spatial learning impairment

BACKGROUND

HIV-1-associated neurocognitive disorders (HAND) progression is related to continued inflammation despite undetectable viral loads and may be caused by early viral proteins expressed by latently infected cells. Astrocytes represent an HIV reservoir in the brain where the early viral neurotoxin negative factor (Nef) is produced. We previously demonstrated that astrocytic expression of Nef in the hippocampus of rats causes inflammation, macrophage infiltration, and memory impairment. Since these processes are affected by TGFβ signaling pathways, and TGFβ-1 is found at higher levels in the central nervous system of HIV-1+ individuals and is released by astrocytes, we hypothesized a role for TGFβ-1 in our model of Nef neurotoxicity.

METHODS

To test this hypothesis, we compared cytokine gene expression by cultured astrocytes expressing Nef or green fluorescent protein. To determine the role of Nef and a TGFβRI inhibitor on memory and learning, we infused astrocytes expressing Nef into the hippocampus of rats and then treated them daily with an oral dose of SD208 (10 mg/kg) or placebo for 7 days. During this time, locomotor activity was recorded in an open field and spatial learning tested in the novel location recognition paradigm. Postmortem tissue analyses of inflammatory and signaling molecules were conducted using immunohistochemistry and immunofluorescence.

RESULTS

TGFβ-1 was induced in cultures expressing Nef at 24 h followed by CCL2 induction which was prevented by blocking TGFβRI with SD208 (competitive inhibitor). Interestingly, Nef seems to change the TGFβRI localization as suggested by the distribution of the immunoreactivity. Nef caused a deficit in spatial learning that was recovered upon co-administration of SD208. Brain tissue from Nef-treated rats given SD208 showed reduced CCL2, phospho-SMAD2, cluster of differentiation 163 (CD163), and GFAP immunoreactivity compared to the placebo group.

CONCLUSIONS

Consistent with our previous findings, rats treated with Nef showed deficits in spatial learning and memory in the novel location recognition task. In contrast, rats treated with Nef + SD208 showed better spatial learning suggesting that Nef disrupts memory formation in a TGFβ-1-dependent manner. The TGFβRI inhibitor further reduced the induction of inflammation by Nef which was concomitant with decreased TGFβ signaling. Our findings suggest that TGFβ-1 signaling is an intriguing target to reduce neuroHIV.

A genome-wide association analysis identifies 16 novel susceptibility loci for carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a common and disabling condition of the hand caused by entrapment of the median nerve at the level of the wrist. It is the commonest entrapment neuropathy, with estimates of prevalence ranging between 5-10%. Here, we undertake a genome-wide association study (GWAS) of an entrapment neuropathy, using 12,312 CTS cases and 389,344 controls identified in UK Biobank. We discover 16 susceptibility loci for CTS with p < 5 × 10^-8. We identify likely causal genes in the pathogenesis of CTS, including ADAMTS17, ADAMTS10 and EFEMP1, and using RNA sequencing demonstrate expression of these genes in surgically resected tenosynovium from CTS patients. We perform Mendelian randomisation and demonstrate a causal relationship between short stature and higher risk of CTS. We suggest that variants within genes implicated in growth and extracellular matrix architecture contribute to the genetic predisposition to CTS by altering the environment through which the median nerve transits.

Study of the mechanism underlying hsa-miR338-3p downregulation to promote fibrosis of the synovial tissue in osteoarthritis patients

Osteoarthritis (OA) is a degenerative joint disease characterized by the degradation of joint cartilage, the formation of osteophyma at joint margins, and synovial changes. Whereas lesions of the joint cartilage were the key point of the research and treatment of osteoarthritis before, a recent study showed that the synovium plays a crucial role in the pathological progress of OA. The inflammatory environment in the joints of OA patients always results in the overactivation of fibroblast-like synoviocytes (FLSs), which produce a multitude of inflammatory factors and media, not only leading to the degradation and injury of the cartilage tissue and promoting the development of osteoarthritis but also resulting in synovial fibrosis and joint stiffness. Therefore, the synovium has attracted increasing attention in the research of OA, and the study of the mechanism of activation of FLSs and the fibrosis of joint synovium may shed new light on OA treatment. By using high-throughput screening, we have identified that hsa-miR338-3p is significantly downregulated in the synovial tissue and joint effusion from OA patients. A functional study showed that overexpression of hsa-miR338-3p in the FLSs inhibited the TGF-β1-induced overactivation of the TGF-β/Smad fibrosis regulation pathway by suppressing TRAP-1 expression and thus reducing the TGF-β1-induced activation of the FLSs and the expression of vimentin and collagen I, two fibrosis markers. Meanwhile, a mechanism study also showed that the upregulation of hsa-miR338-3p reduced Smad2/3 phosphorylation by suppressing TRAP-1 and thus inhibited the TGF-β/Smad pathway and TIMP1, a downstream protein. The present study, for the first time, illustrates the role of hsa-miR338-3p in synovial fibrosis in OA patients and the related mechanism, which is of importance to the treatment of OA and its complications by targeting the FLSs and synovial tissue. Hsa-miR338-3p not only has the potential to be a target for the gene therapy of OA but also has the potential to be a new marker for the diagnosis of clinical progression in OA patients.

Clinical evidence and mechanisms of growth factors in idiopathic and diabetes-induced carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is an entrapment neuropathy caused by compression and irritation of the median nerve, which travels through the carpal tunnel in the wrist. Increased fibrosis is a hallmark of the development and pathology of CTS. Different growth factors have been demonstrated to play a potential role in the development of CTS. Studies have described an increase in the expression of growth factors, including Transforming Growth Factor (TGF-β), Vascular Endothelial Growth Factor (VEGF) and interleukins (growth factors for immune and inflammatory cells) in SSCT (sub-synovial connective tissue) in CTS patients. Additionally, SSCT fibrosis is also marked by increased activation of canonical TGF-β second messenger Smads, increased expression of downstream fibrotic mediators such as connective tissue growth factor (CTGF), increased production of collagen type I, II, III and IV, and decreased expression of matrix metalloproteinases. Anti-fibrotic such as anti-TGF treatment may prove beneficial in idiopathic patients, however, anti VEGF therapy can be successful in the diabetic CTS patients. The present review describes the clinical evidence stating the role of different growth factors in the development of fibrosis in idiopathic and diabetes induced CTS.

Effect of estradiol on fibroblasts from postmenopausal idiopathic carpal tunnel syndrome patients

Fibrosis of the subsynovial connective tissue (SSCT) is a characteristic finding in patients with idiopathic carpal tunnel syndrome (CTS). Idiopathic CTS frequently occurs in postmenopausal women; therefore, female steroid hormones, especially estrogens, may be involved in its development. In this study, we evaluated the effect of the estradiol on the expression of genes and proteins related to fibrosis of SSCT fibroblasts from patients with idiopathic CTS. This study included 10 postmenopausal women (mean age 76 years). Fibroblasts derived from SSCT were treated with estradiol (10^-4 -10^-12  M), and the expression levels of TGF-β-responsive genes were evaluated. The relationships between the expression of untreated estrogen receptor α (ERα) and ERβ and changes in gene expression due to estradiol treatment were examined by quantitative real-time polymerase chain reaction. The effects of 10^-4  M estradiol on collagen type I (Col1) and collagen type III (Col3) protein expression levels were also evaluated by fluorescent staining. The relationships between ERα/β and Col1/3 expression were evaluated by immunohistochemical staining. The reduction in Col1A1 mRNA expression due to estradiol treatment was positively correlated with ERα expression (r = 0.903, p < 0.01). At the protein level, expression of Col1 and Col3 were down-regulated. These results indicated that ERα-mediated signaling may be involved in the regulation of Col1A1, and its regulatory effect may be dependent on the ERα expression level. The accurate evaluation of ERα expression level in the SSCT of individual patients with idiopathic CTS might guide the effective use of new estrogen replacement therapy.

Oral Ibuprofen Interferes with Cellular Healing Responses in a Murine Model of Achilles Tendinopathy

Background:

The attempted healing of tendon after acute injury (overloading, partial tear or complete rupture) proceeds via the normal wound healing cascade involving hemostasis, inflammation, matrix synthesis and matrix remodeling. Depending on the degree of trauma and the nature of the post-injury milieu, a variable degree of healing and recovery of function occurs. Post-injury analgesia is often achieved with NSAIDs such as Ibuprofen, however there is increasing evidence that NSAID usage may interfere with the healing process. This study aimed to investigate the cellular mechanism by which IBU therapy might lead to a worsening of tendon pathology.

Methods:

We have examined the effect of oral Ibuprofen, on Achilles tendon healing in a TGFb1-induced murine tendinopathy model. Dosing was started 3 days after initial injury (acute cellular response phase) and continued for 22 days or started at 9 days after injury (transition to matrix regeneration phase) and given for 16 days. Cellular changes in tendon and surrounding peritenon were assessed using Hematoxylin/Eosin, chondroid accumulation with Safranin O and anti-aggrecan immunohistochemistry, and neo-vessel formation with GSI Lectin histochemistry. Markers of inflammation included histochemical localization of hyaluronan, immunohistochemistry of heavy chain 1 and TNFα-stimulated glycoprotein-6 (TSG6). Cell responses were further examined by RT-qPCR of 84 NFκB target genes and 84 wound healing genes. Biomechanical properties of tendons were evaluated by tensile testing.

Results:

At a clinically-relevant dosage, Ibuprofen prevented the process of remodeling/removal of the inflammatory matrix components, hyaluronan, HC1 and TSG6. Furthermore, the aberrant matrix remodeling was accompanied by activation at day 28 of genes (Col1a2, Col5a3, Plat, Ccl12, Itga4, Stat3, Vegfa, Mif, Col4a1, Rhoa, Relb, F8, Cxcl9, Lta, Ltb, Ccl12, Cdkn1a, Ccl22, Sele, Cd80), which were not activated at any time without the drug, and so appear most likely to be involved in the pathology. Of these, Vegfa, Col4a1, F8, Cxcl9 and Sele, have been shown to play a role in vascular remodeling, consistent with the appearance at 25 days of vasculogenic cell groups in the peritenon and fat pad stroma surrounding the Achilles of the drug-dosed mice. Tensile stiffness (p = 0.004) and elastic modulus (p = 0.012) were both decreased (relative to age-matched uninjured and non-dosed mice) in mice dosed with Ibuprofen from day 3 to day 25, whether injured or not.

Conclusion:

We conclude that the use of Ibuprofen for pain relief during inflammatory phases of tendinopathy, might interfere with the normal processes of extracellular matrix remodeling and cellular control of expression of inflammatory and wound healing genes. It is proposed that the known COX2-mediated anti-inflammatory effect of ibuprofen has detrimental effects on the turnover of a pro-inflammatory HA matrix produced in response to soft-tissue injury, thus preventing the switch to cellular responses associated with functional matrix remodeling and eventual healing.

PDGFR Signaling Mediates Hyperproliferation and Fibrotic Responses of Subsynovial Connective Tissue Cells in Idiopathic Carpal Tunnel Syndrome

Fibrosis of the subsynovial connective tissue (SSCT) is a pathognomonic change in carpal tunnel syndrome (CTS). Identification of molecular targets and anti-fibrotic therapies could provide new treatment strategies for CTS. The contribution of SSCT cells to fibrosis and the signaling pathways that initiate and aggravate fibrosis in CTS remain unknown. Here we report that platelet-derived growth factor receptor alpha (PDGFRα) positive ( + ) cells accumulate in CTS SSCT and that the presence of fibrotic growth factor, PDGF-AA, results in increased proliferation of PDGFRα+ cells via PI3K/Akt signaling pathway. Although PI3K inhibition decreased proliferation, there was no change in fibrosis-related gene expression. Indeed, protein levels of fibrosis signaling mediator TGF-β remained the same and the second messenger, Smad2/3, accumulated in the nucleus. In contrast AMP-activated protein kinase (AMPK) activation, which can be induced with metformin and AICAR inhibited proliferation, TGF-β expression, and altered cell morphology in SSCT cells. Further we show that AMPK activation by metformin reduced collagen III levels and the ratio of Collagen I to Collagen III. Both AICAR and metformin reduced F-actin and significantly reduced the fiber cross alignment. Our results suggest that PDGFRa signaling may be an important fibrosis target and that activators of AMPK, may be an important therapeutic approach for treating CTS.