Sex differences in neuromuscular control of quadriceps.

PURPOSE: Patellofemoral pain syndrome (PFPS) is twice as prevalent in females as males, yet a few studies have evaluated differences in quadriceps muscle control between sexes or across force levels. This study investigated sex differences in quadriceps EMG onset times and amplitude at different force levels during isometric knee extension in asymptomatic males and females and in females with PFPS. METHODS: Thirteen healthy males, 12 healthy females, and 10 females with PFPS performed isometric knee extension ramp contractions at 25%, 50%, and 75% of maximal voluntary contraction (MVC). Surface EMG was recorded from the vastus lateralis (VL), vastus medialis oblique (VMO), vastus medialis (VM), and rectus femoris (RF). RESULTS: Healthy females showed delayed VL (222 ± 67 ms, p = 0.002), VMO (357 ± 101 ms, p = 0.001), and VM (258 ± 62 ms, p < 0.001) recruitment in comparison with healthy males. Healthy males activated the VL earlier than the VM (156 ± 51 ms, p = 0.02) and RF (379 ± 74 ms, p < 0.001), and at a similar time as the VMO; healthy females activated the VL earlier than the VM (192 ± 53 ms, p = 0.004) and VMO (239 ± 73 ms, p = 0.01). A lower VMO:VL activation ratio was found at 25% MVC (p < 0.001) than at higher force levels. CONCLUSIONS: Delayed activation of the VMO relative to the VL has been proposed as a risk factor for PFPS. This study confirms a delay in VMO onset time in females.

Tea (Camellia sinensis L.) flower polysaccharide attenuates metabolic syndrome in high-fat diet induced mice in association with modulation of gut microbiota.

There is a growing body of evidence suggesting that dietary polysaccharides play a crucial role in preventing metabolic syndrome (MetS) through their interaction with gut microbes. Tea (Camellia sinensis L.) flower polysacchride (TFPS) is a novel functional compound known for its diverse beneficial effects in both vivo and vitro. To further investigate the effects of TFPS on MetS and gut microbiota, and the possible association between gut microbiota and their activities, this study was carried out on mice that were fed a high-fat diet (HFD) and given oral TFPS at a dose of 400 and 800 mg/kg·body weight (BW)/d, respectively. TFPS treatment significantly mitigated HFD-induced MetS, evidenced by reductions in body weight, fat accumulation, plasma levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and pro-inflammatory cytokines tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and IL-1ß, along with an increase in plasma IL-10 levels. Furthermore, TFPS induced alterations in the diversity and composition of HFD-induced gut microbiota. Specifically, TFPS influenced the relative abundance of 11 genera, including Lactobacillus and Lactococcus, which showed strong correlations with metabolic improvements and likely contributed to the amelioration of MetS. In conclusion, TFPS exhibits promising prebiotic properties in preventing MetS and regulating gut microbiota.

Macrophage promotes fibroblast activation and kidney fibrosis by assembling a vitronectin-enriched microenvironment.

Background: Renal infiltration of inflammatory cells including macrophages is a crucial event in kidney fibrogenesis. However, how macrophage regulates fibroblast activation in the fibrotic kidney remains elusive. In this study, we show that macrophages promoted fibroblast activation by assembling a vitronectin (Vtn)-enriched, extracellular microenvironment. Methods: We prepared decellularized kidney tissue scaffold (KTS) from normal and fibrotic kidney after unilateral ischemia-reperfusion injury (UIRI) and carried out an unbiased quantitative proteomics analysis. NRK-49F cells were seeded on macrophage-derived extracellular matrix (ECM) scaffold. Genetic Vtn knockout (Vtn-/-) mice and chronic kidney disease (CKD) model with overexpression of Vtn were used to corroborate a role of Vtn/integrin αvß5/Src in kidney fibrosis. Results: Vtn was identified as one of the most upregulated proteins in the decellularized kidney tissue scaffold from fibrotic kidney by mass spectrometry. Furthermore, Vtn was upregulated in the kidney of mouse models of CKD and primarily expressed and secreted by activated macrophages. Urinary Vtn levels were elevated in CKD patients and inversely correlated with kidney function. Genetic ablation or knockdown of Vtn protected mice from developing kidney fibrosis after injury. Conversely, overexpression of Vtn exacerbated renal fibrotic lesions and aggravated renal insufficiency. We found that macrophage-derived, Vtn-enriched extracellular matrix scaffold promoted fibroblast activation and proliferation. In vitro, Vtn triggered fibroblast activation by stimulating integrin αvß5 and Src kinase signaling. Either blockade of αvß5 with neutralizing antibody or pharmacological inhibition of Src by Saracatinib abolished Vtn-induced fibroblast activation. Moreover, Saracatinib dose-dependently ameliorated Vtn-induced kidney fibrosis in vivo. These results demonstrate that macrophage induces fibroblast activation by assembling a Vtn-enriched extracellular microenvironment, which triggers integrin αvß5 and Src kinase signaling. Conclusion: Our findings uncover a novel mechanism by which macrophages contribute to kidney fibrosis via assembling a Vtn-enriched extracellular niche and suggest that disrupting fibrogenic microenvironment could be a therapeutic strategy for fibrotic CKD.

Oxidatively stressed extracellular microenvironment drives fibroblast activation and kidney fibrosis.

Kidney fibrosis is associated with tubular injury, oxidative stress and activation of interstitial fibroblasts. However, whether these events are somehow connected is poorly understood. In this study, we show that glutathione peroxidase-3 (GPX3) depletion in renal tubular epithelium after kidney injury plays a central role in orchestrating an oxidatively stressed extracellular microenvironment, which drives interstitial fibroblast activation and proliferation. Through transcriptional profiling by RNA-sequencing, we found that the expression of GPX3 was down-regulated in various models of chronic kidney disease (CKD), which was correlated with induction of nicotinamide adenine dinucleotide phosphate (NAPDH) oxidase-4 (NOX4). By using decellularized extracellular matrix (ECM) scaffold, we demonstrated that GPX3-depleted extracellular microenvironment spontaneously induced NOX4 expression and reactive oxygen species (ROS) production in renal fibroblasts and triggered their activation and proliferation. Activation of NOX4 by advanced oxidation protein products (AOPPs) mimicked the loss of GPX3, increased the production of ROS, stimulated fibroblast activation and proliferation, and activated protein kinase C-α (PKCα)/mitogen-activated protein kinase (MAPK)/signal transducer and activator of transcription 3 (STAT3) signaling. Silencing NOX4 or inhibition of MAPK with small molecule inhibitors hampered fibroblast activation and proliferation. In mouse model of CKD, knockdown of NOX4 repressed renal fibroblast activation and proliferation and alleviated kidney fibrosis. These results indicate that loss of GPX3 orchestrates an oxidatively stressed extracellular microenvironment, which promotes fibroblast activation and proliferation through a cascade of signal transduction. Our studies underscore the crucial role of extracellular microenvironment in driving fibroblast activation and kidney fibrosis.

A novel diagnostic model for insulinoma.

The aim is to describe a simple and feasible model for the diagnosis of insulinoma. This retrospective study enrolled 37 patients with insulinoma and 44 patients with hypoglycemia not due to insulinoma at the First Affiliated Hospital of Guangxi Medical University. General demographic and clinical characteristics; hemoglobin A1c (HbA1c), insulin and C-peptide concentrations; and the results of 2-h oral glucose tolerance tests (OGTT) were recorded, and a logistic regression model predictive of insulinoma was determined. Body mass index (BMI), HbA1c concentration, 0-h C-peptide concentration, and 0-h and 1-h plasma glucose concentrations (P < 0.05 each) were independently associated with insulinoma. A regression prediction model was established through multivariate logistics regression analysis: Logit p = 7.399+(0.310 × BMI) - (1.851 × HbA1c) - (1.467 × 0-h plasma glucose) + (1.963 × 0-h C-peptide) - (0.612 × 1-h plasma glucose). Using this index to draw a receiver operating characteristic (ROC) curve, the area under the curve (AUC) was found to be 0.957. The optimal cut-off value was - 0.17, which had a sensitivity of 89.2% and a specificity of 86.4%. Logit P ≥ - 0.17 can be used as a diagnostic marker for predicting insulinoma in patients with hypoglycemia.

Expression of miR-4739 in Gastric cancer and its Relationship with Clinical Pathological Features of Patients.

Objective: To investigate the expression level of miR-4739 in gastric cancer (GC), analyze its diagnostic value in GC and the relationship with clinical pathological characteristics, and analyze its impact on the prognosis of patients. Methods: A total of 96 patients with GC who underwent radical gastrectomy in our hospital from March 2017 to June 2021 were selected. GC tissues from all patients were collected, and normal tissues adjacent to cancer were collected as controls. The expression level of miR-4739 in tissues was detected, the relationship between miR-4739 and different pathological features was analyzed, and the diagnostic value of miR-4739 in GC was analyzed. All patients were followed up after the operation, and the survival time of the patients was set as from the day of the first operation to 1 d when the patients died or the follow-up ended. Results: The relative expression level of miR-4739 in the GC tissue was (0.39 ± 0.06), lower than that in the paracancerous tissue (1.18 ± 0.19) (P < 0.05). The AUC of miR-4739 in the diagnosis of GC was 0.705. When the Youden index was 0.320 and the optimal cutoff value was 0.37, the sensitivity was 95.30% and the specificity was 36.70%. The expression level of miR-4739 in our patient was related to the differentiation degree, lymph node metastasis, tumor diameter, and TNM stage (P < 0.05). During the follow-up period, 26 of 96 patients died, and the survival rate was 72.92% (26/96). The median survival time was 29 months in the miR-4739 LE group, which was shorter than 39 months in the miR-4739 HE group (P < 0.05). Univariate analysis showed that age, degree of differentiation, lymph node metastasis, tumor diameter, TNM staging, and miR-4739 expression were all related to the prognosis of the patient (P < 0.05). Multivariate analysis showed that differentiation degree, lymph node metastasis, tumor diameter, TNM staging, and miR-4739 expression were all independent factors affecting the prognosis of the patients (P < 0.05). Conclusion: The expression of miR-4739 in GC tissue was down-regulated, and its level was related to the degree of differentiation, lymph node metastasis, tumor diameter, and TNM stage. The expression level of miR-4739 has certain diagnostic value for patients with GC, and the prognosis of patients in LE group was worse than that in HE group.

Fibrillin-1-enriched microenvironment drives endothelial injury and vascular rarefaction in chronic kidney disease.

Endothelial cell injury leading to microvascular rarefaction is a characteristic feature of chronic kidney disease (CKD). However, the mechanism underlying endothelial cell dropout is poorly defined. Here, we show a central role of the extracellular microenvironment in controlling endothelial cell survival and proliferation in CKD. When cultured on a decellularized kidney tissue scaffold (KTS) from fibrotic kidney, endothelial cells increased the expression of proapoptotic proteins. Proteomics profiling identified fibrillin-1 (FBN1) as a key component of the fibrotic KTS, which was up-regulated in animal models and patients with CKD. FBN1 induced apoptosis of endothelial cells and inhibited their proliferation in vitro. RNA sequencing uncovered activated integrin αvß6/transforming growth factor-ß signaling, and blocking this pathway abolished FBN1-triggered endothelial injury. In a mouse model of CKD, depletion of FBN1 ameliorated renal fibrotic lesions and mitigated vascular rarefaction. These studies illustrate that FBN1 plays a role in mediating vascular rarefaction by orchestrating a hostile microenvironment for endothelial cells.

The relationship between cardiac muscularis propria and clinical outcomes of peroral endoscopic myotomy in achalasia.

BACKGROUND AND AIM: Achalasia patients usually present lower esophageal sphincter thickening, which can impact the expansibility of cardia. We aimed to investigate the effect of cardiac muscularis propria (MP) on perioperative adverse events (AEs) and treatment outcomes of patients treated with peroral endoscopic myotomy (POEM). METHODS: We retrospectively reviewed 114 patients with achalasia undergoing pre-POEM endoscopic ultrasonography (EUS) between May 2013 and November 2019. Cardiac MP thickness was measured using EUS. POEM failure was defined as Eckardt score >3. Risk factors for perioperative AEs and POEM failure were identified. RESULTS: Patients were divided into the thin (n = 52) and the thick group (n = 62) based on the median of cardiac MP thickness (3.0 mm). Perioperative AEs rate of the thin group seemed to be slightly higher than that of the thick group (11.5% vs. 4.8%, P = 0.30). During a median follow-up of 30 months (range 1-77), 100 patients completed follow-up, 16 (16%) of which occurred clinical failure. The clinical outcomes of patients in the thin group were significantly poorer than those patients in the thick group (P = 0.006). Cardiac MP thickness was an independent risk factor for POEM failure (hazard ratio 3.9, P = 0.02; Cox regression), but not the risk factor for perioperative AEs (odds ratio 2.6, P = 0.2; logistic regression). CONCLUSION: Cardiac MP thickness could be a novel predictive factor for POEM failure in patients with achalasia.

Hip position and sex differences in motor unit firing patterns of the vastus medialis and vastus medialis oblique in healthy individuals.

Weakness of the vastus medialis oblique (VMO) has been proposed to explain the high prevalence of knee pain in female subjects. Clinicians commonly use exercises in an attempt to preferentially activate the VMO. Recently, our group found evidence to support clinical theory that the VMO is neurologically distinct from the vastus medialis (VM). However, the ability to voluntarily activate these muscle subsections is still disputed. The aim of this study was to determine if VM and VMO activation varies between sexes and if control of the two muscles is different between rehabilitation exercises. Thirteen men and 13 women performed isometric straight leg raises in two hip positions, neutral hip rotation and 30 degrees lateral hip rotation. Bipolar intramuscular fine-wire electrodes were inserted into the VM and VMO to obtain motor unit recruitment thresholds and initial firing rates at recruitment. Linear mixed models and Tukey post hoc tests were used to assess significant differences in 654 motor units. Women demonstrated faster motor unit firing rate at recruitment, 1.18 ± 0.56 Hz higher than men. Motor units fired 0.47 ± 0.19 Hz faster during neutral hip rotation compared with lateral hip rotation. The VMO motor units were recruited 2.92 ± 1.28% earlier than the VM. All motor units were recruited 3.74 ± 1.27% earlier during neutral hip rotation than lateral hip rotation. Thus the VM and the VMO can be activated differentially, and their motor unit recruitment properties are affected by sex and hip position. NEW & NOTEWORTHY This is the first study to reveal differential activation of the vastus medialis oblique from the vastus medialis in clinical exercise protocols. Our research group used fine-wire electrodes to examine EMG signals of the vastus medialis oblique and vastus medialis to avoid possible cross talk. We also consider the effect of sex on motor unit firing patterns because of higher prevalence of knee pain in women, and yet few studies evaluating the sex differences in neuromuscular control.

Menstrual cycle mediates vastus medialis and vastus medialis oblique muscle activity.

PURPOSE: Sports medicine professionals commonly describe two functionally different units of the vastus medialis (VM), the VM, and the vastus medialis oblique (VMO), but the anatomical support is equivocal. The functional difference of the VMO is principle to rehabilitation programs designed to alleviate anterior knee pain, a pathology that is known to have a greater occurrence in women. The purpose of this study was to determine whether the motor units of the VM and VMO are differentially recruited and if this recruitment pattern has an effect of sex or menstrual cycle phase. METHODS: Single motor unit recordings from the VM and VMO were obtained for men and women during an isometric ramp knee extension. Eleven men were tested once. Seven women were tested during five different phases of the menstrual cycle, determined by basal body temperature mapping. The recruitment threshold and the initial firing rate at recruitment were determined from 510 motor unit recordings. RESULTS: The initial firing rate was lower in the VMO than that in the VM in women (P < 0.001) but not in men. There was no difference in recruitment thresholds for the VM and VMO in either sex or across the menstrual cycle. There was a main effect of menstrual phase on initial firing rate, showing increases from the early follicular to late luteal phase (P = 0.003). The initial firing rate in the VMO was lower than that in the VM during ovulatory (P = 0.009) and midluteal (P = 0.009) phases. CONCLUSION: The relative control of the VM and VMO changes across the menstrual cycle. This could influence patellar pathologies that have a higher incidence in women.