Roles of TGF-β/Smad signaling pathway in pathogenesis and development of gluteal muscle contracture

Cellular and Molecular Mechanisms of Hypertrophy of Ligamentum Flavum

Hypertrophy of the ligamentum flavum (HLF) is a common contributor to lumbar spinal stenosis (LSS). Fibrosis is a core pathological factor of HLF resulting in degenerative LSS and associated low back pain. Although progress has been made in HLF research, the specific molecular mechanisms that promote HLF remain to be defined. The molecular factors involved in the onset of HLF include increases in inflammatory cytokines such as transforming growth factor (TGF)-β, matrix metalloproteinases, and pro-fibrotic growth factors. In this review, we discuss the current understanding of the mechanisms involved in HLF with a particular emphasis on aging and mechanical stress. We also discuss in detail how several pathomechanisms such as fibrosis, proliferation and apoptosis, macrophage infiltration, and autophagy, in addition to several molecular pathways involving TGF-β1, mitogen-activated protein kinase (MAPKs), and nuclear factor-κB (NF-κB) signaling, PI3K/AKT signaling, Wnt signaling, micro-RNAs, extracellular matrix proteins, reactive oxygen species (ROS), etc. are involved in fibrosis leading to HLF. We also present a summary of the current advancements in preclinical animal models for HLF research. In addition, we update the current and potential therapeutic targets/agents against HLF. An improved understanding of the molecular processes behind HLF and a novel animal model are key to developing effective LSS prevention and treatment strategies.

LncRNA MALAT1 Knockdown Alleviates Fibrogenic Response in Human Endometrial Stromal Cells Via the miR-22-3p/TGFβR1/Smad2/3 Pathway

Intrauterine adhesion (IUA) resulting from irreversible fibrotic repair of endometrium is the main cause of secondary infertility in women, and current therapeutic approaches to IUA are limited. Increasing evidence has suggested the important role of competitive endogenous RNA (ceRNA) in IUA pathologies. This study aimed to investigate the long noncoding RNA (lncRNA) metastasis associated lung adenocarcinoma transcript 1 (MALAT1)-associated ceRNA in IUA development. We harvested endometrial tissues from patients with or without IUA and extracted endometrial stromal cells (ESCs) from normal endometrial tissues. Transforming growth factor β1 (TGF-β1) was used to induce fibrosis in ESCs. The expression of transforming growth factor β receptor 1 (TGFβR1), α-smooth muscle actin, phosphorylated suppressor of mother against decapentaplegic (p-Smad)2/3, collagen type I alpha 1, MALAT1, and microRNA (miR)-22-3p in endometrial tissues and ESCs was measured by reverse transcription quantitative polymerase chain reaction (RT-qPCR) or western blotting. Pearson's correlation analysis was conducted to assess the correlation between miR-22-3p expression or TGFβR1 and MALAT1 expression in endometrial tissues. The expression of TGFβR1 in ESCs was also evaluated by immunofluorescence staining. The location of MALAT1 was examined by fluorescence in situ hybridization. Luciferase reporter assays were performed to verify the binding relationship between MALAT1 or TGFβR1 and miR-22-3p. Cell viability was assessed via cell counting kit-8 assays. Our findings revealed that lncRNA MALAT1 and TGFβR1 were upregulated while miR-22-3p was downregulated in IUA endometrial tissues or TGF-β1-stimulated ESCs, and lncRNA MALAT1 expression was negatively correlated with miR-22-3p expression while being positively correlated with TGFβR1 expression in IUA endometrial tissues. Additionally, lncRNA MALAT1 was mainly located in the cytoplasm of ESCs and directly targeted miR-22-3p to regulate TGFβR1 expression. Moreover, knockdown of lncRNA MALAT1 exerted anti-fibrotic effects on ESCs by targeting miR-22-3p, and miR-22-3p overexpression inhibited the fibrosis of ESCs by binding to TGFβR1 3'untranslated region. Collectively, lncRNA MALAT1 promotes endometrial fibrosis by sponging miR-22-3p to regulate TGFβR1 and Smad2/3, and inhibition of MALAT1 may represent a promising therapeutic option for suppressing endometrial fibrosis.

CTRP6 alleviates endometrial fibrosis by regulating Smad3 pathway in intrauterine adhesion†

Intrauterine adhesion (IUA) is manifestations of endometrial fibrosis and excessive extracellular matrix deposition. C1q/tumor necrosis factor-related protein-6 (CTRP6) is a newly identified adiponectin paralog which has been reported to modulate the fibrosis process of several diseases; however, the endometrial fibrosis function of CTRP6 remains unknown. Our study aimed to assess the role of CTRP6 in endometrial fibrosis and further explore the underlying mechanism. Here, we found that the expression of CTRP6 was downregulated in the endometrial tissues of IUA. In vitro experiments demonstrated the reduced level of CTRP6 in facilitated transforming growth factor-β1 (TGF-β1)-induced human endometrial stromal cells (HESCs). In addition, CTRP6 inhibited the expression of α-smooth muscle actin (α-SMA) and collagen I in TGF-β1-treated HESCs. Mechanistically, CTRP6 activated the AMP-activated protein kinase (AMPK) and protein kinase B (AKT) pathway in HESCs, and AMPK inhibitor (AraA) or PI3K inhibitor (LY294002) pretreatment abolished the protective effect of CTRP6 on TGF-β1-induced fibrosis. CTRP6 markedly decreased TGF-β1-induced Smad3 phosphorylation and nuclear translocation, and AMPK or AKT inhibition reversed these effects. Notably, CTRP6-overexpressing treatment alleviated the fibrosis of endometrium in vivo. Therefore, CTRP6 ameliorates endometrial fibrosis, among which AMPK and AKT are essential for the anti-fibrotic effect of CTRP6 via the Smad3 pathway. Taken together, CTRP6 may be a potential therapeutic target for the treatment of intrauterine adhesion.

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

miR-491-5p Inhibits Emilin 1 to Promote Fibroblasts Proliferation and Fibrosis in Gluteal Muscle Contracture via TGF-β1/Smad2 Pathway

Gluteal muscle contracture (GMC) is a chronic fibrotic disease of gluteal muscles due to multiple etiologies. Emilin 1 plays a determinant role in fibers formation, but its role in the progression of GMC remains unclear. The present study was aimed to search for the predictive role and regulatory mechanism of Emilin 1 on GMC. Here, Protein and mRNA expression of Emilin 1 were decreased in GMC tissues compared to normal muscle tissues. Using the analysis of target prediction, Emilin 1 was observed to be a potential downstream sponge of miR-491-5p. In comparison to Emilin 1, miR-491-5p showed an aberrant elevation in GMC tissues, which was further proven to have a negative correlation with Emilin 1. The direct binding of miR-491-5p to Emilin 1 mRNA was confirmed by luciferase reporter gene assay, and miR-491-5p mimics inhibited, while miR-491-5p inhibitor promoted the protein expression and secretion of Emilin 1 in contraction bands (CB) fibroblasts. Additionally, miR-491-5p mimics promoted the expression of cyclin-dependent kinase 2 and cyclin D1 and the proliferation of CB fibroblasts, which could be reversed by Emilin 1 overexpression. Mechanistically, miR-491-5p mimics possibly activated transforming growth factor β1 (TGF-β1)/Smad3 signal cascade via binding to 3’-untranslated region of Emilin 1 mRNA, thereby promoting the progression of fibrosis of CB fibroblasts. Collectively, miR-491-5p inhibited Emilin 1 expression, and subsequently promoted CB fibroblasts proliferation and fibrosis via activating TGF-β1/Smad3 signal axis. MiR-491-5p might be a potentially effective biomarker for predicting GMC, providing a novel therapeutic strategy for GMC.

Spinal-pelvic sagittal parameters in patients with gluteal muscle contracture: an imaging study

Background

Gluteal muscle contracture (GMC) may cause abnormal spinal alignment as well as hip and pelvic deformities. The spine-pelvis alignment of GMC patients is unclear. This study aimed to describe the spine-pelvis sagittal alignment in patients with GMC and to explore the impact of GMC on the pathogenesis of low back pain (LBP).

Methods

Radiological analysis was performed in 100 patients with GMC and 100 asymptomatic volunteers who acted as the control group. Sagittal parameters were measured by two independent raters and their averages were presented on lateral radiographs of the whole spine, including pelvic incidence (PI), sagittal vertical axis (SVA), pelvic tilt (PT), lumbar lordosis (LL), sacral slope (SS), thoracic kyphosis (TK), and the relationship between PI and LL (expressed as PI-LL). All cases were categorized into one of three classes based on the apex position of lumbar lordosis and were further divided into three groups by the PI value. The GMC and control parameters were compared and the correlations between the parameters in the GMC group were analysed.

Results

The PI value of the GMC group was significantly less than that of the control group (42.38 ± 10.90° vs 45.68 ± 7.49°, P < 0.05). There was no difference found between the key parameters (SVA, PT, and PI-LL), which correlated with outcomes in adult deformity. No differences of SS were found between the two groups (P > 0.05). The GMC group showed lower average LL (42.77 ± 10.97° vs 46.41 ± 9.07°) and TK (17.34 ± 9.50° vs 20.45 ± 8.02°) compared with the control group (P < 0.05). LL was correlated with PI, SS, PT, TK (P < 0.01) and SVA (P < 0.05). TK and SVA were not correlated with any parameters except LL and pairwise correlations were found among PI, SS, and PT. There were no differences found between the distributions of the lumbar lordosis apex of GMC and the control but the range of SS in apex groups 3 and 4 did differ. GMC patients had the most small-PI value (44%) while approximately 64% of asymptomatic individuals had a normal PI. Interobserver variability was sufficient for all parameters calculated by the intraclass correlation coefficient (ICC).

Conclusions

Gluteal muscle contracture causes a low PI which may contribute to low back pain. Patients with GMC present the same global sagittal spinal-pelvic balance as asymptomatic individuals due to a compensatory mechanism through excessive flat lumbar and thoracic curves. Future studies on the relationship between spinal-pelvic sagittal and coronal alignment and low back pain are needed to understand the mechanical forces involved in the onset of GMC.

Effects of dietary methionine on growth performance, muscle nutritive deposition, muscle fibre growth and type I collagen synthesis of on-growing grass carp (Ctenopharyngodon idella)

In the current research, a 60-d experiment was conducted with the purpose of exploring the impacts of methionine (Met) on growth performance, muscle nutritive deposition, muscle fibre growth and type I collagen synthesis as well as the related signalling pathway. Six diets (iso-nitrogenous) differing in Met concentrations (2·54, 4·85, 7·43, 10·12, 12·40 and 15·11 g/kg diets) were fed to 540 grass carp (178·47 (SD 0·36) g). Results showed (P < 0·05) that compared with Met deficiency, optimal level of dietary Met (1) increased feed intake, feed efficiency, specific growth rate and percentage weight gain (PWG); (2) increased fish muscle protein, lipid and free amino acid contents and improved fish muscle fatty acid profile as well as increased protein content in part associated with the target of rapamycin complex 1 (TORC1)/S6K1 signalling pathway; (3) increased the frequency distribution of muscle fibre with >50 µm of diameter; (4) increased type I collagen synthesis partly related to the transforming growth factor-β1/Smads and CK2/TORC1 signalling pathways. In conclusion, dietary Met improved muscle growth, which might be due to the regulation of muscle nutritive deposition, muscle fibre growth and type I collagen synthesis-related signal molecules. Finally, according to PWG and muscle collagen content, the Met requirements for on-growing grass carp (178-626 g) were estimated to be 9·56 g/kg diet (33·26 g/kg protein of diet) and 9·28 g/kg diet (32·29 g/kg of dietary protein), respectively.

Surgical Release of Gluteal Fibrosis in Children Results in Sustained Benefit at 5-Year Follow-up

BACKGROUND

Gluteal fibrosis (GF) is a fibrotic infiltration of the gluteal muscles resulting in functionally limiting contracture of the hips and is associated with injections of medications into the gluteal muscles. It has been reported in numerous countries throughout the world. This study assesses the 5-year postoperative range of motion (ROM) and functional outcomes for Ugandan children who underwent surgical release of GF.

METHODS

A retrospective cohort study of children who underwent release of GF in 2013 at Kumi Hospital in Eastern Uganda. Functional outcomes, hip ROM, and scar satisfaction data were collected for all patients residing within 40 km of the hospital.

RESULTS

One hundred eighteen children ages 4 to 16 at the time of surgery were treated with surgical release of GF in 2013 at Kumi Hospital. Of those 118, 89 were included in this study (79.5%). The remaining 29 were lost to follow-up or lived outside the study's radius. Detailed preoperative ROM and functional data were available for 53 of the 89 patients. In comparison with preoperative assessment, all patients postoperatively reported ability to run normally (P<0.001), sit upright in a chair (P<0.001), sit while eating (P<0.001), and attend the entire day of school (P<0.001). Passive hip flexion (P<0.001) improved when compared with preoperative measurements. In all, 85.2% (n=75) of patients reported satisfaction with scar appearance as "ok," "good," or "excellent" 29.2% (n=26) of patients reported back or hip complaints.

CONCLUSIONS

Overall, the 5-year postoperative outcomes suggest that surgical release of GF improves ROM and functional quality of life with sustained effect.

LEVEL OF EVIDENCE

Level IV-case series.

Benzyl alcohol accelerates recovery from Achilles tendon injury, potentially via TGF-β1/Smad2/3 pathway

Benzyl alcohol (BnOH) is a natural colorless liquid organic compound that plays an important role in bacteriostatic and anesthetic processes. It is also used to relieve the nerve and ganglionic pain. In this study, we assessed the effect of topical application of BnOH on the Achilles tendon healing process. Sprague Dawley rats were subjected to an experimentally induced wound in the tendon area and then randomized into four groups. Normal saline (0.5 mL) was applied to rats in control group, and BnOH at the concentrations of 0.5 mL 0.075%, 0.15%, 0.3% were applied to the BnOH treatment groups, respectively. Wound treatment with BnOH led to significantly faster functional recovery than with saline. Moreover, treatment of wounds with 0.3% BnOH accelerated the healing process faster than with 0.075% and 0.15% BnOH. Histological analysis of healed wounds that had been treated with BnOH showed more collagen and blood capillaries and fewer inflammatory cells compared to the control. To study the mechanism of the process, the expression of mRNA of TGF-β1, Smad2/3 and Smad7 and protein of TGF-β1, p-Smad2/3 and Smad7 were quantified by real-time PCR and Western blotting, respectively. Results of this study showed that wounds treated with BnOH significantly enhanced the expression of TGF-β1 and Smad2/3 and reduced the expression of Smad7. In general, the current study demonstrated that BnOH improved the recovery process of tendon healing through the promotion of collagen with angiogenesis and showed that TGF-β plays a role in BnOH treatment of tendon healing.

Transforming growth factor-β1 in intrauterine adhesion

Intrauterine adhesion (IUA), led by trauma to the basal layer, can prevent the endometrium from growing, resulting in complications in females, such as infertility and amenorrhea. Transforming growth factor-β1 (TGF-β1) plays a crucial role in inducing and promoting the differentiation and proliferation of mesenchymal cells, in the secretion of extracellular matrix-associated components, and is a major cytokine in initiating and terminating tissue repair downstream of the TGF-β/Smad signaling pathway. Some evidence supports that TGF-β1 is closely associated with the occurrence and development of IUA, and is regarded as an early risk factor of disease recurrence. Furthermore, the role of TGF-β1 has been demonstrated to be potentially regulated by a variety of cytokines, hormones, enzymes, and microRNAs. This review provides an overview of the expression, function, and regulation of TGF-β1 in IUA, with a brief discussion and perspectives on its future clinical implications on the diagnosis and treatment of IUA.

miR-29a is a potential protective factor for fibrogenesis in gluteal muscle contracture

Circulating miRNAs have been proposed as the effective diagnostic biomarkers for muscular fibrosis-associated diseases. However, circulating biomarkers for early diagnosis of contracture muscles are limited in gluteal muscle contracture (GMC) patients. Here we sought to explore the abnormally expressed miRNAs in plasma and contraction bands of GMC patients. The results showed miR-29a-3p expression in plasma and contraction bands tissue was significantly reduced in GMC patients compared with normal control. Cell viability and levels of proliferation-associated protein cyclin D1 and cyclin-dependent-kinase 2 (CDK2) were powerfully inhibited by miR-29a mimics and enhanced by miR-29a inhibitor compared with negative control. Furthermore, miR-29a mimics effectively impeded, while miR-29a inhibitor enhanced the expression of collagen I and collagen III, followed by the secretion of transforming growth factor beta1 (TGF-beta1), TGF-beta3 and connective tissue growth factor (CTGF) in primary human contraction bands (CB) fibroblasts. The miR-29a-3p negatively regulated the expression of TGF-beta1 through binding to the 3´ UTR region of SERPINH1 (encoding heat shock protein HSP47), but had no effect on Smad2 activity. The miR-29a-3p was inversely correlated with HSP47 in contraction bands tissue from GMC patients. Collectively, miR-29a was notably depressed and regulated cell viability and fibrosis by directly targeting HSP47 in GMC, which suggest that circulating miR-29a might be a potential biomarker for early diagnosis and provides a novel therapeutic target for GMC.

A possible prediction of dystocia at the time of cesarean delivery: Gluteal muscle contracture, a single center experience from China

The study assessed the pelvic dimensions by computed tomography (CT) performed for gluteal muscle contracture women, and evaluated the impact of malformations on several essential obstetric parameters.The CT pelvimetry was retrospectively performed in 25 gluteal muscle contracture women selected consecutively whether they had delivery history or not. Among the pelvic inlet plane, the mid plane and the outlet plane, 12 indicators including the transverse diameter of the pelvic inlet, the conjugate vera, the diagonal conjugate, the biischial diameter, the anteroposterior diameter of the middle pelvis, transverse outlet, the posterior sagittal diameter of outlet, the conjugate of the outlet, the anterior sagittal diameter of the outlet, the curvature and length of the sacrum, the angle of pubic arch were collected.Finally, the mean age of these women was 26.6 ± 5.0 years. Most pelvises had anteroposterior elliptical appearance in inlet and size of the female pelvis. The most statistically different and most clinically significant indicator was the biischial diameter, gluteal muscle contracture women were 95.6 ± 9.3 mm and the normal women from other study were 105.0 ± 7.9 mm, the comparison showed a significant difference (P < .001).Generally, most gluteal muscle contracture women had features of anthropoid pelvis which were quite different from normal Chinese female. These results may serve as a basis for future studies to assess its utility and prognostic value for a safe vaginal delivery in gluteal muscle contracture women.

The role of KDR in intrauterine adhesions may involve the TGF-β1/Smads signaling pathway

The aim of this study was to investigate the role of kinase-insert domain-containing receptor (KDR) in intrauterine adhesions (IUA) and its mechanism. The Case group consisted of 92 patients diagnosed with IUA, and the Control group included 86 patients with uterine septum who had normal endometrium verified with an uteroscope. In addition, 50 rats were randomly assigned into Control, Sham, Model, NC-siRNA, and KDR-siRNA groups. Rats in the Model, NC-siRNA, and KDR-siRNA groups were induced by uterine curettage and lipopolysaccharide (LPS) treatment to establish the IUA model. Then, immunohistochemistry was applied for detection of VEGF and KDR expression, HE staining was used for observation of the endometrial morphology and gland counting, Masson staining for measurement of the degree of endometrial fibrosis, and qRT-PCR and western blot for the expression of KDR, VEGF, MMP-9, as well as TGF-β1/Smads pathway-related proteins. Compared with the Control group, the mRNA and protein expressions of KDR were significantly higher in IUA endometrial tissues, and the expression of KDR was positively correlated to the severity of IUA. In addition, the injection of si-KDR increased the number of endometrial glands, reduced the area of fibrosis, inhibited mRNA and protein expression of KDR and VEGF, up-regulated the expression of MMP-9 and Smad7, and decreased the expression level of TGF-β1, p-Smad2, p-Smad3, and Smad4 in rats with IUA. Highly-expressed KDR was related to patients' severity of IUA, and silencing KDR may prevent the occurrence and development of IUA via TGF-β1/Smads signaling pathway and up-regulating the expression of MMP-9.

Histology and molecular pathology of iliotibial tract contracture in patients with gluteal muscle contracture

The present study aimed to examine the pathologic changes of the iliotibial tract and discusses its relationship with gluteal muscle contracture. Samples of contractual iliotibial tracts were collected from six patients with contractures of the gluteal muscles and iliotibial tracts during their surgical treatment. Samples of normal iliotibial tracts were collected from six patients receiving surgeries for avascular necrosis of the femoral head who had no contractures of the gluteal muscles and iliotibial tracts. The tissue samples were stained using Hematoxylin and Eosin (H&E), Masson’s trichrome, and Sirius Red. The mRNA and protein levels of various tissue repair genes were determined using quantitative real-time PCR and Western blotting. Both the normal and contractual iliotibial tracts consisted of type I and III collagens. The contractual iliotibial tracts had a significantly higher proportion of type III collagen in comparison with the normal iliotibial tracts. The mRNA expression levels and protein levels of tissue repair genes TGFβ 1, bFGF, and matrix metalloproteinase-1 (MMP-1) in the contractual iliotibial tracts were up-regulated in comparison with that in the normal iliotibial tracts. However, the mRNA expression levels and protein levels of tissue inhibitors of metalloproteinase-1 (TIMP) in the contractual iliotibial tracts were down-regulated in comparison with that in the normal iliotibial tracts. The contractures of both the gluteal muscles and the iliotibial tracts share similar histology and molecular pathology. Our results indicate that iliotibial tract contracture is secondary to the gluteal muscle contracture and is a constant tissue repair process.

The role of arthroscopic release of gluteal muscle contracture in improving patellofemoral instability

Background

Gluteal muscle contracture (GMC) is a notable problem in some developing countries and includes features such as a snapping sound of the hip, abnormal gait, and unusual posture when patients squat with the knees together. Arthroscopic release can not only resolve symptoms, as previously reported, but can also greatly improve accompanying patellofemoral instability. This study was conducted to evaluate the effect of arthroscopic release of GMC on patellofemoral instability and its underlying mechanism.

Methods

A total of nearly 500 patients who underwent arthroscopic release of GMC over 2.5 years were filtered, and 54 patients were enrolled in the study. The selected research subjects all had combined patellofemoral instability preoperatively. The Lysholm scores and CT scans of the knee were evaluated pre- and postoperatively.

Results

The mean follow-up time was 12.2 months. All of the surveyed patients had satisfactory clinical outcomes for hip snapping sounds and abnormal gait. In addition, a significant difference (p < 0.05) was observed between pre- and postoperative Lysholm scores, along with significant knee pain relief. Furthermore, the changes in CT scan parameters were significant as well. The average patellar tilt angle (PTA), patellofemoral index (PFI), and lateral patellar displacement (LPD) were obviously decreased (p < 0.05) after the release. Conversely, the mean lateral patellofemoral angle (LPFA) showed a clear difference (p < 0.05) between preoperative and postoperative CT examinations.

Conclusions

Arthroscopic release of GMC can reduce the tilt and lateral shift of the patella and enhance its stability due to the release of the iliotibial band.

Gluteal Fibrosis and Its Surgical Treatment

BACKGROUND

The objective of this study was to analyze the literature regarding the diagnosis, pathogenesis, and prevalence of gluteal fibrosis (GF) and the outcomes of treatment.

METHODS

We searched PubMed, Embase, and Cochrane literature databases, from database inception to December 15, 2016. We used the following search terms including variants: "contracture," "fibrosis," "injections," "injections, adverse reactions,' "gluteal," and "hip." All titles and abstracts of potentially relevant studies were scanned to determine whether the subject matter was potentially related to GF, using predefined inclusion and exclusion criteria. If the abstract had subject matter involving GF, the paper was selected for review if full text was available. Only papers including ≥10 subjects who underwent surgical treatment were included in the systematic analysis. Data abstracted included the number of patients, patient age and sex, the type of surgical treatment, the method of outcome measurement, and outcomes and complications.

RESULTS

The literature search yielded 2,512 titles. Of these, 82 had a focus on GF, with 50 papers meeting the inclusion criteria. Of the 50 papers reviewed, 18 addressed surgical outcomes. The surgical techniques in these papers included open, minimally invasive, and arthroscopic release and radiofrequency ablation. Of 3,733 operatively treated patients in 6 reports who were evaluated on the basis of the criteria of Liu et al., 83% were found to have excellent results. Few papers focused on the incidence, prevalence, and natural history of GF, precluding quantitative synthesis of the evidence in these domains.

CONCLUSIONS

This study provided a systematic review of surgical outcomes and a summary of what has been reported on the prevalence, diagnosis, prognosis, and pathogenesis of GF. Although GF has been reported throughout the world, it requires further study to determine the exact etiology, pathogenesis, and appropriate treatment. Surgical outcomes appear satisfactory.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Role of S1P and the Related Signaling Pathway in the Development of Tissue Fibrosis

Tissue fibrosis, including pulmonary fibrosis, hepatic fibrosis, and cardiac fibrosis, is an important stage in the development of many diseases. It can lead to structural damage and dysfunction and even severe carcinogenesis or death. There is currently no effective method for the treatment of fibrosis. At present, the molecular mechanism of tissue fibrosis has not yet been fully elucidated, but many studies have demonstrated that it is involved in conveying the complex messages between fibroblasts and various cytokines. Sphingosine 1-phosphate (S1P) is a naturally bioactive sphingolipid. S1P and the related signaling pathways are important intracellular metabolic pathways involved in many life activities, including cell proliferation, differentiation, apoptosis, and cellular signal transduction. Increasing evidence suggests that S1P and its signaling pathways play an important role in the development of tissue fibrosis; however, the mechanisms of these effects have not yet been fully elucidated, and even the role of S1P and its signaling pathways are still controversial. This article focuses on the role of S1P and the related signaling pathways in the development of fibrosis of lung, liver, heart, and other tissues, with emphasis on the application of inhibitors of some of molecules in the pathway in clinical treatment of fibrosis diseases.

Smad4-dependent regulation of type I collagen expression in the muscle of grass carp fed with faba bean

Smad4 is the key regulator in the transforming growth factor β1 (TGF-β1)/Smads signal pathway, and is also the crux of the regulation of type I collagen expression in mammals. In fish, however, the relationship between Smad4 and type I collagen is still unknown. Given the widely accepted importance of type I collagen in fish muscle hardness, we seek to explore this issue by analyzing the expressions of the TGF-β1/Smads pathway molecules and type I collagen in the muscle of crisp grass carp fed with faba bean, which shows increased muscle hardness. The study found that (1) in the process of feeding the grass carp with faba bean, the mRNA and protein expressions of TGF-β1, Smad2 and Smad4 all increased along with the increase of type I collagen expression (Col1α1 and Col1α2); (2) one day after the injection of Smad4 over-expression vector, both mRNA and protein expressions of Col1α1 and Col1α2 significantly increased, reaching the maximum on the 2nd and 5th day, respectively; (3) one day after the injection of Smad4 RNAi interference vector, the mRNA and protein expressions of Col1α1 and Col1α2 decreased, reaching the minimum on the 5th day. These results revealed that Smad4 is the major regulator of type I collagen in the muscle of grass carp fed with faba bean. This study would provide an important mechanistic basis for nutritional regulation of type I collagen in the muscle of fish.

Burden of gluteal fibrosis and post-injection paralysis in the children of Kumi District in Uganda

Background

The purpose of this study was to estimate the prevalence of postinjection paralysis (PIP) and gluteal fibrosis (GF) among children treated in a rural Ugandan Hospital.

Methods

We conducted a retrospective cohort study by reviewing the musculoskeletal clinic and community outreach logs for children (age < 18 yrs) diagnosed with either PIP or GF from Kumi Hospital in Kumi, Uganda between 2013 and 2015. We estimated the prevalence as a ratio of the number of children seen with each disorder over the total population of children seen for any musculoskeletal complaint in musculoskeletal clinic and total population of children seen for any medical complaint in the outreach clinic.

Results

Of 1513 children seen in the musculoskeletal clinic, 331 (21.9% (95% CI 19.8–24.1%)) had PIP and another 258 (17.1% (95% CI 15.2–19.0%)) had GF as their diagnosis. Of 3339 children seen during outreach for any medical complaint, 283 (8.5% (95% CI 7.6–9.5%)) had PIP and another 1114 (33.4% (95% CI 31.8–35.0%)) had GF. Of patients with GF, 53.9% were male with a median age of 10 years (50% between 7 and 12 years old). Of patients with PIP, 56.7% were male with a median age of 5 years (50% between 2 and 8 years old).

Conclusion

PIP and GF comprise over 30% of clinical visits for musculoskeletal conditions and 40% of outreach visits for any medical complaint in this area of Uganda. The high estimated prevalence in these populations suggest a critical need for research, treatment, and prevention.

Comparison of the clinical effects of arthroscopic surgery vs. open surgery for grade II gluteal muscle contracture in adults

The aim of the present study was to compare the clinical effects of arthroscopic surgery with open surgery for grade II gluteal muscle contracture (GMC) in adults and to discuss the indication and technique for arthroscopic GMC release. The clinical data of 113 adult patients with grade II GMC between 2011 and 2016 was retrospectively collected. Among these patients, 72 patients received open surgery and 41 received arthroscopic surgeryy. The 2 groups were compared in terms of surgical duration, incision size, blood loss, hospital stay, analgesic dose and ranking of postoperative functions and effects. Mean surgical duration was significantly greater in the arthroscopic surgery group (P<0.001). Mean incision size, blood loss, hospital stay and analgesic dose were significantly lower in the arthroscopic surgery group compared with the open surgery group (P<0.001). There was no significant difference observed regarding the ranking of functions and effects between the two groups. These results suggest that existing untreated patients with GMC having low-severity (grade II) contractures of limited area are suitable for arthroscopic surgery. The advantages of arthroscopic GMC release include limited surgical trauma, a small incision, low blood loss and fewer surgical complications.

Midazolam inhibits chondrogenesis via peripheral benzodiazepine receptor in human mesenchymal stem cells

Midazolam, a benzodiazepine derivative, is widely used for sedation and surgery. However, previous studies have demonstrated that Midazolam is associated with increased risks of congenital malformations, such as dwarfism, when used during early pregnancy. Recent studies have also demonstrated that Midazolam suppresses osteogenesis of mesenchymal stem cells (MSCs). Given that hypertrophic chondrocytes can differentiate into osteoblast and osteocytes and contribute to endochondral bone formation, the effect of Midazolam on chondrogenesis remains unclear. In this study, we applied a human MSC line, the KP cell, to serve as an in vitro model to study the effect of Midazolam on chondrogenesis. We first successfully established an in vitro chondrogenic model in a micromass culture or a 2D high‐density culture performed with TGF‐β‐driven chondrogenic induction medium. Treatment of the Midazolam dose‐dependently inhibited chondrogenesis, examined using Alcian blue‐stained glycosaminoglycans and the expression of chondrogenic markers, such as SOX9 and type II collagen. Inhibition of Midazolam by peripheral benzodiazepine receptor (PBR) antagonist PK11195 or small interfering RNA rescued the inhibitory effects of Midazolam on chondrogenesis. In addition, Midazolam suppressed transforming growth factor‐β‐induced Smad3 phosphorylation, and this inhibitory effect could be rescued using PBR antagonist PK11195. This study provides a possible explanation for Midazolam‐induced congenital malformations of the musculoskeletal system through PBR.

Comparison of arthroscopic versus open surgery on external snapping hip caused by gluteal muscle contracture

PURPOSE

To compare the outcomes of contracture release by arthroscopic versus open surgical approach in patients with external snapping hip (ESH) caused by gluteal muscle contracture (GMC).

METHODS

Medical records of patients with ESH due to GMC who underwent open surgery (n = 44) or arthroscopic surgery (n = 48) between October 2008 and October 2014 were reviewed. Patients were followed up at 1, 3, 12, and 24 months postoperatively. Operation time, incision length, postoperative pain, postoperative complication rate, and recurrence rate were compared between the 2 groups. Hip adduction, and Harris Hip Scores (HHS) at 1 and 2 years postoperatively were compared between the groups and with preoperative data.

RESULTS

Mean operation time did not differ between the 2 groups (p>0.05). The arthroscopic surgery group had smaller incisions (p<0.05), less postoperative pain (p<0.05), lower complication rates (p<0.05) than did the open surgery group. The recurrence rates were similar for the 2 groups (p>0.05). Hip adduction, and HHS 1 year and 2 years postoperatively were significantly better postoperatively than they had been preoperatively for both groups (all p<0.01), and were similar for the 2 groups (all p>0.05).

CONCLUSIONS

Arthroscopic release of contracture tissue is a safe and effective approach for the treatment of ESH caused by GMC, with the advantages of small scars, less postoperative pain, fewer complications compared with open surgery.

Comparison of arthroscopic versus open surgery on external snapping hip caused by gluteal muscle contracture

PURPOSE

To compare the outcomes of contracture release by arthroscopic versus open surgical approach in patients with external snapping hip (ESH) caused by gluteal muscle contracture (GMC).

METHODS

Medical records of patients with ESH due to GMC who underwent open surgery (n = 44) or arthroscopic surgery (n = 48) between October 2008 and October 2014 were reviewed. Patients were followed up at 1, 3, 12, and 24 months postoperatively. Operation time, incision length, postoperative pain, postoperative complication rate, and recurrence rate were compared between the 2 groups. Hip adduction, and Harris Hip Scores (HHS) at 1 and 2 years postoperatively were compared between the groups and with preoperative data.

RESULTS

Mean operation time did not differ between the 2 groups (p>0.05). The arthroscopic surgery group had smaller incisions (p<0.05), less postoperative pain (p<0.05), lower complication rates (p<0.05) than did the open surgery group. The recurrence rates were similar for the 2 groups (p>0.05). Hip adduction, and HHS 1 year and 2 years postoperatively were significantly better postoperatively than they had been preoperatively for both groups (all p<0.01), and were similar for the 2 groups (all p>0.05).

CONCLUSIONS

Arthroscopic release of contracture tissue is a safe and effective approach for the treatment of ESH caused by GMC, with the advantages of small scars, less postoperative pain, fewer complications compared with open surgery.