Contraction Ability Research Articles

DOCK1/ELMO1/Rac1 Signaling is Essential for Vitreous-Induced Migration and Contraction of ARPE19 Cells.

Purpose: To test the effects of dedicator of cytokinesis protein 1 (DOCK1) with its binding partner engulfment and cell motility protein 1 (ELMO1)-Rac1 axis on the vitreous-induced biological functions of retinal pigment epithelial (RPE) cells. Methods: Rac1 activity in RPE cells after vitreous stimulation was detected via a pull-down assay. The related protein expression levels were examined via western blot analysis. DOCK1 and ELMO1 knockdown cells were generated via CRISPR-Cas9 technology. Cytoskeletal reorganization was detected by immunofluorescent localization of F-actin. Cell proliferation, migration, invasion, and contraction ability were measured via the CCK8 assay, wound healing assay, transwell invasion assay, and collagen contraction assay. Results: Rac1 activity was significantly elevated in ARPE-19 cells stimulated with vitreous fluid for 30 min to 3 h. Depletion of either DOCK1 or ELMO1 with CRISPR/Cas9 attenuated vitreous-stimulated Rac1 activity, thus reversing the vitreous-induced cytoskeletal rearrangements. The functional cell biology results revealed that deficiencies of DOCK1 and ELMO1 significantly impeded the migration, invasion, and contraction abilities of vitreous-stimulated human RPE cells. Conclusion: This study demonstrated that the DOCK1/ELMO1-Rac1 axis plays an essential role in the pathogenesis of proliferative vitreoretinopathy (PVR), thus suggesting that interruption of this axis has potential for PVR therapy.

Self-Healing Yet Strong Actuator Materials with Muscle-Like Diastole and Contraction via Multilevel Relaxations.

Skeletal muscles represent a role model in soft robotics featuring agile locomotion and incredible mechanical robustness. However, existing actuators lack an optimal combination of actuation parameters (including actuation modes, work capacity, mechanical strength, and damage repair) to rival biological tissues. Here, a biomimetic structural design strategy via multilevel relaxations (α/β/γ/δ-relaxation) modulation is proposed for mechanical robust and healable actuator materials with muscle-like diastole and contraction abilities by orientational alignment of dendritic polyphenol-modified nano-assembles in eutectogels. The anisotropic hierarchical micro-nanostructures assembled by supramolecular interaction mimic the relative slippage of actin filaments and myosin in muscles, ensuring bistable actuation through rapid thermal α-relaxation and expansion. Furthermore, kinetically active secondary β/γ/δ-relaxation at reconfigurable interfaces can conquer the limited self-healing ability of fixed-orientation polymeric chains. The obtained artificial muscle exhibits high output actuation, robust mechanical properties (tensile strength of 33.5MPa), and desired functional, mechanical self-healing efficiency (89.7%), exceeding typical natural muscles in living systems. The bionic micro-nano design strategy achieves bottom-up cooperative relaxation modulation to integrate all-round performance of natural muscles, which paves the way for substantial advancements in next-generation intelligent robotics.

Bioelectrical stimulation therapy for muscle injuries in aerobics athletes

This article aims to explore the recovery effect of the bioelectrical stimulation therapy on muscle injuries in aerobics athletes. Non-invasive medical techniques are adopted to activate muscle tissue through electrical currents, promoting muscle contraction ability and functional recovery. This article selects 100 aerobics athletes with muscle injuries through questionnaire surveys and interviews. The Modulo Plus electrical stimulation device is used, and personalized treatment plans are set. Muscle changes before and after treatment are monitored using electromyography and ultrasound technology. In the single-blind experiment, in the fourth week, the pain score of the experimental group decreases to 2.4 points; the functional recovery score increases to 75.2 points; the flexibility measurement reaches 19.2 cm. In the case-control study, the bioelectrical stimulation therapy cures all athletes in the sixth week, exceeding the conventional therapy’s 35 patients, and has a lower recurrence rate. In the cohort study, athletes who use the bioelectrical stimulation therapy for a long time have a shorter average recovery time of 15.3 days and a recurrence rate of 16%. In the muscle recovery experiment, in the eighth week after treatment, the electromyographic activity level of the experimental group increases to 58.6 μV; the muscle thickness increases to 4.3 mm; the echo intensity increases to 63.1 dB; the fatigue characteristic score drops to 2.1. These data indicate that the bioelectrical stimulation therapy has significant effects in reducing pain, promoting functional recovery, improving flexibility, shortening recovery time, and reducing recurrence rates and pain scores, thereby providing an effective treatment option for the recovery of muscle injuries in aerobics athletes.

Short-Term Culture of Human Hyalocytes Retains Their Initial Phenotype and Displays Their Contraction Abilities.

Hyalocytes are the main vitreal cell types with critical functions in health and vitreoretinal diseases. Our aim was to develop cultures of human hyalocytes and verify the retention of their initial cellular features after 3 and 6 days of culturing (3 d and 6 d) by analyzing and comparing a few morphological and functional parameters. Vitreous samples (n = 22) were collected and vitreous cells and bead-enriched hyalocytes were developed and compared (3 d vs. 6 d cultures). Vitreous and conditioned media were tested for collagen, vascular endothelial growth factor (VEGF), transforming growth factor β1 (TGFβ1), nerve growth factor (NGF), matrix metalloproteinases (MMPs)/tissue inhibitors of metalloproteinases (TIMPs) and alpha-smooth muscle actin (αSMA) expression (ELISA, array/IP/WB, RT-PCR). Cells were observed at light and fluorescent microscopy (phenotypical properties) and tested for their 3D collagen gel contraction abilities. An increased expression of collagens, vimentin, fibronectin, and the MMP9/TIMP1 ratio were observed in vitreous tissues. In 3 d cultures, collagens and MMP9 were upregulated while the related tissue-enzymes were deregulated. Vitreous samples also showed high levels of TGFβ1, VEGF, and NGF, and this protein signature was retained at 3 d while decreased at 6 d. The original phenotype (low αSMA) was retained at 3 d from seeding while an increased αSMA expression was observed at 6 d; NGF/trkANGFR was expressed in cultured hyalocytes and partially drives the collagen retraction. The vitreous print comparison between untouched and cultured hyalocytes allowed us, on one side, to select 3 d cultures and, on the other, to highlight the neuroprotective/contractile NGF in vitro hyalocytes effects. The possibility of scoring reactive hyalocytes would represent an interesting aspect of screening the vitreoretinal interface severity.

Phosphoproteomics of PLN R14del heart tissue reveals major myocyte degenerate phenotype, and is attenuated by PLN antisense treatment in vitro

Abstract Background/Purpose: Phospholamban (PLN) p.Arg14del (R14del, R14Δ/+) is a pathogenic variant that can cause cardiomyopathy, characterized by PLN protein aggregation, ultimately leading to heart failure (HF). The exact pathophysiology is unknown, we aim to uncover R14Δ/+ disease mechanisms and study potential treatment using PLN antisense oligonucleotides (PLN-ASOs). Methods Phosphoproteomics was performed on human heart tissue from end-stage R14Δ/+ patients (N=6) versus other etiologies of HF (N=10) as a control. CRISPR-Cas9 engineered R14Δ/+ and isogenic control (WT) induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were extensively characterized, including the phosphoproteome, calcium transients (FLUO 4-AM), mitochondrial respiration (Seahorse Mito Stress Test) and contractility in dynamic engineered heart tissues (dyn-EHTs) before and after PLN-ASO treatment, and the results were validated in R14Δ/+ iPSC-CMs derived from R14Δ/+ patients. Results Phosphoproteomics of heart tissue from R14Δ/+ vs. other etiologies of HF identified 138 differentially expressed proteins (DEPs) and 317 differentially expressed phosphoproteins (DEPPs), therewith establishing a disease-specific signature. Phosphoproteomics of WT vs. R14Δ/+ iPSC-CMs identified 451 DEPs and 1046 DEPPs. Gene ontology analysis of end-stage R14Δ/+ heart tissue and iPSC-CMs revealed a large overlap. Here, R14Δ/+ showed to have great impact on contraction (e.g. SYNPO2L, MYH10, TTN) and calcium (e.g. AHNAK, HRC, RYR2). In line with this, functional characterization revealed that R14Δ/+ iPSC-CMs have an increased Ca2+ systolic velocity and accelerated calcium transient (decreased T50 and T90), that associated with altered calcium-related DEPPs (e.g. RYR2). In dyn-EHTs, R14Δ/+ dyn-EHTs have a decreased contraction duration, time-to-peak and ability to pace, associated with altered contractility-related DEPPs (e.g. SYNPO2L, MYH7, TTN). PLN-ASOs dose-dependently altered PLN mRNA expression and protein levels in iPSC-CMs, and 62 DEPs and 372 DEPPs were identified. PLN-ASOs increased Ca2+ diastolic velocity, which associated with altered calcium-related DEPPs (e.g. PLN, AHNAK, HRC). PLN-ASOs increased the ability of dyn-EHTs to pace and therewith improved contractility, which associated with altered contractility-related DEPPs (e.g. SYNPO2L, MYH7, TTN). PLN-ASOs dose-dependently increased basal respiration and ATP production, which associated with altered mitophagy-related DEPs (GABARAPL2 and MAP1LC3). These functional characteristics were validated in R14Δ/+ patient iPSC-CMs. Discussion: R14Δ/+ cardiomyocytes have a degenerative phenotype characterized by altered calcium transients and reduced contractility and PLN-ASOs attenuate these characteristics and improve metabolism.

Safety and feasibility of "Pant-Shaped" anastomosis in laparoscopic-assisted total gastrectomy: Study of 210 cases at a single center.

Advancements in laparoscopic technology have popularized laparoscopic total gastrectomy over traditional open surgery, yet postoperative complications like anastomotic leakage and stenosis persist, particularly in esophagojejunostomy. To address this, since 2017, the authors have introduced the "Pant-Shaped" esophagojejunostomy as an improvement over the classic Roux-en-Y method, especially beneficial for patients with small intestinal diameters or those with gastric body cancer or Siewert III. To assess the viability and safety of employing 'Pant-Shaped' anastomosis following laparoscopic-assisted total gastrectomy. A method of descriptive case study was used. In our department of the First Affiliated Hospital of Wannan Medical College, records of 210 patients who underwent laparoscopic-assisted total gastrectomy for gastric body cancer or adenocarcinoma at the junction of esophagus and jejunum with "Pant-Shaped" anastomosis between January 2017 and December 2022 were examined. Clinicopathological features and postoperative conditions were also examined and assessed. The mean age of the 164 male and 46 female research participants was 69.2 ± 8.3 years. There was a mean estimated blood loss of 63.4 ± 29.7 ml, an anastomosis time of 25.9 ± 3.0 minutes, an operation time of 208.2 ± 40.4 minutes, and a postoperative hospital stay of 12.2 ± 8.0 days. Nine patients (4.3%) experienced postoperative problems (Clavien-Dindo > grade II), including two episodes of anastomotic leakage that were resolved with irrigation and drainage, anti-infection therapy, and nutritional assistance. After an unforeseen reoperation, two cases of duodenal stump leaking were resolved. Anastamotic hemorrhage was treated with hemostasis and blood transfusion, and the patient made a full recovery. Due to a Peterson's hernia, one patient required emergent open surgery. three months subsequent to LATG. The "Pant-Shaped" anastomosis method after laparoscopic-assisted total gastrectomy is simple, easy to promote, and has fewer complications. It is a safe and feasible modified method for esophagojejunostomy, especially suitable for patients with poor intestinal dilation and contraction ability and small jejunal diameter.

Asperuloside inhibits the activation of pancreatic cancer-associated fibroblasts via activating transcription factor 6

BackgroundPancreatic cancer-associated fibroblasts (CAFs) play a crucial role in tumor progression and immune evasion. Asperuloside (ASP) is an iridoid glycoside with potential anti-tumor properties. This study aimed to explore the molecular mechanisms of ASP on CAFs, particularly focusing on its effects on activating transcription factor 6 (ATF6), a key regulator of endoplasmic reticulum stress.MethodCAFs were treated with different concentrations of ASP (0, 1, 3, and 5 mM), and the role of ATF6 was investigated by over-expressing it in CAFs. Subsequently, western blot was used to detect ATF6, α-smooth muscle actin (α-SMA), fibroblast activating protein (FAP), and vimentin protein levels in CAFs. The collagen gel contraction assay and Transwell assay were applied to evaluate the contraction and migration ability of CAFs. In addition, the interleukin (IL)-6, C–C motif chemokine ligand (CCL)-2, and C-X-C motif chemokine ligand (CXCL)-10 levels were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR).ResultsCAFs had significantly higher expression levels of α-SMA, FAP, and vimentin compared to normal fibroblasts (NFs). ASP significantly inhibited the activation, contraction, and migration of CAFs in a concentration-dependent manner. ASP treatment also reduced the expression of cytokines (IL-6, CCL2, and CXCL10) and down-regulated ATF6 levels. Over-expression of ATF6 mitigated the inhibitory effects of ASP.ConclusionASP exerts its anti-tumor effects by down-regulating ATF6, thereby inhibiting the activation and function of pancreatic CAFs. These findings suggest that ASP could be a promising therapeutic agent for pancreatic cancer by modulating the tumor microenvironment.

Low-intensity pulsed ultrasound combined with ST36 modulate gastric smooth muscle contractile marker expression via RhoA/Rock and MALAT1/miR-449a/DLL1 signaling in diabetic rats.

Low-intensity pulsed ultrasound (LIPUS) combined with acupoint can promote gastric motility of diabetic rats. The switch of gastric smooth muscle cell (GSMCs) phenotype was related to the diabetes-induced gastric dysfunction, but the mechanism is not clearly elucidated. This study was aimed at exploring the underlying mechanism of LIPUS stimulation application in diabetic gastroparesis rats. In this study, Sprague-Dawley male rats were divided into three groups: control group (CON), diabetic gastroparesis group (DGP), and LIPUS-treated group (LIPUS). LIPUS irradiation was performed bilaterally at ST36 for 20 min per day for 4 weeks. The gastric emptying rate was measured by ultrasound examination. Contraction ability of GSMCs was assessed by muscle strip experiment. The expression of related proteins or mRNAs including α-SMA, SM22α, MHC, RhoA, Rock2, p-MYPT1, MYPT1, p-MLC, MLC, MALAT1, miR-449a, and DLL1 was detected by different methods such as western blotting, RT-qPCR, immunohistochemistry, and immunofluorescence staining, as appropriate. (a) LIPUS stimulation at ST36 could improve the gastric motility dysfunction of diabetic rats. (b) LIPUS increased RhoA, Rock2, p-MYPT1, and p-MLC expression level. (c) MALAT1 and DLL1 contents were decreased, but the level of miR-449a was increased in the LIPUS group. LIPUS may affect the contractile marker expression of gastric smooth muscle through the RhoA/Rock and MALAT1/miR-449a/DLL1 pathway to ameliorate DGP.

The relationship between flat foot and lower limb muscle strength in teenage basketball athletes

Background: Teenage basketball athletes may experience problems with lower limb muscle strength, which can affect their performance due to factors such as the shape of the arches pedis, muscle length and shortness, fatigue levels, muscle contraction ability, and the presence of flat feet, where the medial arch is flattened against the ground. This study aimed to determine the relationship between flat feet and lower limb muscle strength in adolescent basketball athletes in Tabanan Regency. Methods: This study's design was observational analytic with a cross-sectional study direction. It was conducted at junior high and high schools in Tabanan Regency and involved 62 teenage basketball athletes. The inclusion criteria were basketball athletes with flat feet aged 14-17, while the exclusion criteria were a history of fracture or lower limb injury. Lower limb muscle strength was measured using a leg dynamometer, while flat foot was assessed using a wet footprint test. Results: The result of the association test using Spearman’s Rho Test obtained a correlation coefficient value (r) -0.173, which means a unidirectional relationship with a very weak correlation level with a p-value=0.180 (p<0.05), which means there is no significant relationship. Conclusion: There was no relationship between flat foot and lower limb muscle strength in teenage basketball athletes. The correlation coefficient value indicates a unidirectional relationship with a very weak correlation level.

Computational Approaches Molecular Docking and MD Simulation Establishes the Potential COVID-19 Main Protease Inhibitors from Natural Products

Aim: COVID-19 was classified as a pandemic by the World Health Organization (WHO) on March 11, 2020. No reliable cure, however, was found. To prevent viral replication, complementary therapy with antiviral and antimalarial medications were used. However, due to their synthetic origin, they have a lot of side effects. To overcome this bane natural origin drugs were repositioned. Background: As repositioned drugs do not undergo a pro-long process of pre-clinical trial, hence, they play an excellent role in the spillover of pathogens. The main protease (6LU7) enzyme found in severe acute respiratory syndrome coronavirus-2 (SAR-CoV-2) is essential for viral replication. Thus, it acts as a hotspot in drug discovery. Objective: A molecular docking computational approach was used to determine the ability of the binding contract between the selected 3D-models of COVID-19 protease target and proposed natural compounds pristimerin, amazoquinone, kendomycin, celastrol, 20-epi-isoguesterinol, phenanthrenequinone, taxodione, maytenoquinone, hippeastrine, ammothamnine, 28-hydroxy isoiguesterin, hemanthamine, alisol-B, stigmasterol, β-pinene,and β-sitosterol through Autodock v.1.5.6 software. Method: The present study is designed to perform in-silico studies using molecular docking (Autodock tool v.1.5.6), Discovery Studio 2017 R2 client, Patch dock, SWISS-ADME prediction, and molecular simulation (Desmond simulation package of Schrodinger) between 6LU7 and natural origin compounds. Result: The results of docking study performed between 6LU7 and compounds pristimerin, amazoquinone, kendomycin, celastrol, 20-epi-isoguesterinol, phenanthrenequinone, taxodione, maytenoquinone, hippeastrine, ammothamnine, 28-hydroxy isoiguesterin, hemanthamine, alisol-B, stigmasterol, β-pinene, and β-sitosterol, showed binding energy as -9.68, -7.34, -5.34, -4.63, -4.24, -4.13, -4.08, -3.85, -3.83, -3.7, -3.6, -3.57, -3.54, -3.39, -3.18, and -3.03 Kcal/mol, respectively. It can be shown that the Pristimerin-6LU7 protein complex was maintained throughout the simulation since the ligand RMSDs varied with a maximum value of 4.2Å during the first 10 ns, followed by more stable interactions for the remaining time of the simulation. Conclusion: The goal of the current work was to find inhibitors for both prophylactic and therapeutic usage in COVID-19 patients.

Using machine learning to construct the diagnosis model of female bladder outlet obstruction based on urodynamic study data.

To intelligently diagnose whether there is bladder outlet obstruction (BOO) in female with decent detrusor contraction ability by focusing on urodynamic study (UDS) data. We retrospectively reviewed the UDS data of female patients during urination. Eleven easily accessible urinary flow indicators were calculated according to the UDS data of each patient during voiding period. Eight diagnosis models based on back propagation neural network with different input feature combination were constructed by analyzing the correlations between indicators and lower urinary tract dysfunction labels. Subsequently, the stability of diagnostic models was evaluated by five-fold cross-validation based on training data, while the performance was compared on test dataset. UDS data from 134 female patients with a median age of 51 years (range, 27-78 years) were selected for our study. Among them, 66 patients suffered BOO and the remaining were normal. Applying the 5-fold cross-validation method, the model with the best performance achieved an area under the receiver operating characteristic curve (AUC) value of 0.949±0.060 using 9 UDS input features. The accuracy, sensitivity, and specificity for BOO diagnosis model in the testing process are 94.4%, 100%, and 89.3%, respectively. The 9 significant indicators in UDS were employed to construct a diagnostic model of female BOO based on machine learning algorithm, which performs preferable classification accuracy and stability.

APP-based treatment of urgency and mixed urinary incontinence in women: factors associated with long-term satisfaction

PurposeApp-based treatment of urgency (UUI) and mixed (MUI) urinary incontinence has proved to be effective. To further improve treatment, it will be beneficial to analyze baseline and treatment-related factors that are associated with satisfaction.MethodsA secondary analysis was conducted of data from a randomized controlled trial (RCT) assessing an app for UUI or MUI treatment, encompassing 98 women for whom there was long-term treatment satisfaction data. All participants completed a short-term (15 weeks) and a long-term (15 months) follow-up questionnaire after being given access to treatment. The outcome was a 3-item question on current treatment satisfaction at the long-term follow-up. Factors potentially associated with the outcome were analyzed using the chi-square test, Student’s t test or logistic regression.ResultsAt the long-term follow-up, 58% of the women were satisfied with the treatment. The most important baseline variable associated with satisfaction was incontinence-related quality of life (International Consultation on Incontinence Questionnaire (ICIQ) − Lower Urinary Tract Symptoms Quality of Life Module) (OR 0.91, 95% CI 0.58–0.97). Short-term follow-up variables associated with long-term treatment satisfaction were improvement in the ability to endure urgency (OR 4.33, 95% CI 1.43–13.12), and confidence in pelvic floor contraction ability (OR 2.67, 95% CI 1.04–6.82).ConclusionApp-based treatment for UUI and MUI may be an alternative first-line treatment that is satisfactory to many women over the long-term. Furthermore, short-term treatment that focuses on improving the ability to endure urgency, and confidence in pelvic floor contraction ability, can also be recommended for long-term satisfaction.

Effects of Gender and Vitamin D on Vascular Reactivity of the Carotid Artery on a Testosterone-Induced PCOS Model

The negative cardiovascular effects of polycystic ovary syndrome (PCOS) and vitamin D deficiency (VDD) have been discussed previously; however, the sex differences between PCOS females and males are not yet known. Our aim was to investigate the effect of PCOS and VDD in the carotid artery of male and female Wistar rats. Females were treated with transdermal testosterone (Androgel) for 8 weeks, which caused PCOS. VDD and vitamin D supplementation were accomplished via diet. The carotid arteries’ contraction and relaxation were examined using myography. Receptor density was investigated using immunohistochemistry. In PCOS females, angiotensin receptor density, angiotensin II-induced contraction, androgen receptor optical density, and testosterone-induced relaxation increased. The increased contractile response may increase cardiovascular vulnerability in women with PCOS. As an effect of VDD, estrogen receptor density increased in all our groups, which probably compensated for the reduced relaxation caused by VDD. Testosterone-induced relaxation was decreased as a result of VDD in males and non-PCOS females, whereas this reduction was absent in PCOS females. Male sex is associated with increased contraction ability compared with non-PCOS and PCOS females. VDD and Androgel treatment show significant gender differences in their effects on carotid artery reactivity. Both VDD and PCOS result in a dysfunctional vascular response, which can contribute to cardiovascular diseases.

Mechanisms boosting material embodied intelligence to realize self-healing soft robots

The recent introduction of self-healing soft materials in robotics is a major step towards sustainable next generation robots. By manufacturing soft robots out of these smart materials, we integrate a self-healing ability and increase the physical intelligence of these systems. However, the embodied intelligence in the material level needs to be augmented by incorporating assistive mechanisms in the system level with minimized control, enabling healing of damage in different sizes and in diverse working conditions. These assistive mechanisms can provide damage detection, damage closure, healing stimuli providing, health monitoring, or a combination of the previous. In this paper, we present two different mechanisms for an autonomous healing of damages; (i) Embedding a healable heater in a self-healing soft actuator to increase the temperature required for an efficient healing, while it allows detecting the damage and monitoring the health of the system. (ii) Incorporating shape memory alloy wires in a self-heling soft bending actuator, with simultaneous sealing through contraction and heating abilities. Apart from assisting in the healing action, both mechanisms play a part in the actuation of the bending robots as strain limiting elements. These assistive mechanisms will overcome the limitation on the material level, leading to robots that can self-heal in applications outside of laboratories and factories.

Electromyographic characterization of limb flexion, extension and their special exercise movements in high level distance runners

Abstract The study of EMG characteristics of high-level distance runners in limb flexion, extension, and their special exercise movements is beneficial to developing competitive distance running sports. In this study, high-level distance runners were used as the research object, and the sEMG test in EMG analysis was used to compare the general distance runners, and the changes of MPF, FC, and IEMG were obtained during the limb flexion, extension, and special exercise movements of high-level distance runners. When the FC was 100Hz, the MPF values of high-level distance runners were 64MV2/Hz, while the MPF values of average-distance runners were 45 MV2/Hz. When the muscle strength reached 50%, the IEMG values of rectus abdominis, biceps femoris, and gastrocnemius were 52%, 45 and 56%, respectively, in high-level distance runners, while the IEMG values of average distance runners were 47%, 42%, and 50%, respectively and 50%, respectively. Through the data analysis, the high-level long-distance runners could maintain a higher exercise state and perform at a stable level despite the gradual muscle fatigue, their muscle strength and contraction ability were stronger, and their explosive muscle power and potential were greater than the average long-distance runners.

Oenothera biennis cell culture produce lignans activating Piezo1 triggering the Myosin Light Chain Kinase depending pathways

Piezo1 and Piezo2 are mechanoreceptors involved in sensing both internal and external mechanical forces converting them in electrical signals to the brain.Piezo1 is mainly expressed in the endothelial system and in epidermis sensing shear stress and light touch. The internal traction forces generated by Myosin Light Chain Kinase (MYLK) activate Piezo1, regulating cell contraction.We observed Oenothera biennis cell culture hydro-soluble extract (ObHEx) activated MYLK regulating cell contraction ability. The aim of this work was to test the hypothesis that ObHEx activates Piezo1 through MYLK pathway using CHO cell overexpressing Piezo1, HUVEC and SHSY5Y cells endogenously expressing high levels of Piezo1. Results showed that ObHEx extracts were able to activate Piezo1 and the effect is due to Liriodendrin and Salvadoraside, the two most abundant lignans produced by the cell culture. The effect is lost in presence of MYLK specific inhibitors confirming the key role of this pathway and providing indication about the mechanism of action in Piezo1 activation by lignans.In summary, these results confirmed the connection between Piezo1 and MYLK, opening the possibility of using lignans-containing natural extracts to activate Piezo1.

Characterization of rat gastric myogenic contractions and modulation by oxytocin and arginine-vasopressin

BackgroundInterstitial cells of Cajal generate slow wave gastric electrical activity, initiating spontaneous muscle contractions. This becomes dysrhythmic during nausea when [Arg8]-vasopressin (AVP) is also released. In human stomach AVP increased spontaneous contraction activity and muscle tone, not neuronally-mediated contractions. Rodents cannot vomit, releasing the related hormone, oxytocin (OT) instead. We hypothesised that rat stomach would behave differently. Experimental approachSpontaneous and electrically-evoked (EFS) contractions were measured in rat forestomach and antrum circular muscle. Custom software defined spontaneous contractions by analysing eight motility parameters. ResultsThe forestomach was quiescent. Irregular antrum contractions became regular adjacent to the pylorus (1.7 ± 0.4 mN; 1.2 ± 0.1 contractions/min, n = 12). These were unaffected by tetrodotoxin (10−6 M), atropine (10−6 M) and L-NAME (3 × 10−4 M). In both regions, AVP (pEC50∼9.0) and OT (∼0.5 log10-unit less potent) caused contraction (greater in antrum), competitively antagonized by, respectively, SR49059 (pKB∼9.5) and L371257 (pKB∼9.0), reduced by tetrodotoxin but unaffected by atropine. In the antrum, AVP and OT (∼2 log10-units less potent/efficacious) regularized and increased spontaneous contraction amplitude, frequency, rates of contraction/decay. In both regions, EFS-evoked contractions, abolished by atropine/tetrodotoxin, were reduced by AVP and OT, with AVP more potent and efficacious, particularly in forestomach. ConclusionIrregular spontaneous contractions of gastric antrum suggest variable ICC-muscle coupling. AVP and less potently, OT, enhanced frequency and force of contractions via V1A and OT receptors. Compared with human, differences in contraction regularity, potency and ability of AVP/OT to affect neuronal function suggests caution when using rat stomach to model ICC functions and nauseagenic stimuli.

Abnormally elevated expression of ACTA2 of circular smooth muscle leads to hyperactive contraction in aganglionic segments of HSCR

BackgroundActin Alpha 2 (ACTA2) is expressed in intestinal smooth muscle cells (iSMCs) and is associated with contractility. Hirschsprung disease (HSCR), one of the most common digested tract malformations, shows peristaltic dysfunction and spasm smooth muscles. The arrangement of the circular and longitudinal smooth muscle (SM) of the aganglionic segments is disorganized. Does ACTA2, as a marker of iSMCs, exhibit abnormal expression in aganglionic segments? Does the ACTA2 expression level affect the contraction function of iSMCs? What are the spatiotemporal expression trends of ACTA2 during different developmental stages of the colon?MethodsImmunohistochemical staining was used to detect the expression of ACTA2 in iSMCs of children with HSCR and Ednrb−/− mice, and the small interfering RNAs (siRNAs) knockdown technique was employed to investigate how Acta2 affected the systolic function of iSMCs. Additionally, Ednrb−/− mice were used to explore the changes in the expression level of iSMCs ACTA2 at different developmental stages.ResultsThe expression of ACTA2 is higher in circular SM in the aganglionic segments of HSCR patients and Ednrb−/− mice than in normal control children and mice. Down regulation of Acta2 weakens the contraction ability of intestinal smooth muscle cells. Abnormally elevated expression of ACTA2 of circular smooth muscle occurs since embryonic day 15.5 (E15.5d) in aganglionic segments of Ednrb−/− mice.ConclusionsAbnormally elevated expression of ACTA2 in the circular SM leads to hyperactive contraction, which may cause the spasm of aganglionic segments in HSCR.

Targeting histone deacetylase 9 represses fibrogenic phenotypes in buccal mucosal fibroblasts with arecoline stimulation

Background/purposeOral submucosal fibrosis (OSF) is a premalignant disorder positively associated with betel nut chewing. Recent studies supported the promising benefits of histone deacetylase (HDAC) inhibitors for fibrosis treatment. Here we aim to clarify the pro-fibrogenic role of HDAC9 in regulating OSF. Materials and methodsHealthy and OSF specimens were collected to investigate the clinical significance of HDAC9. Chronic arecoline treatment process was used to induce arecoline-mediated myofibroblasts-related activation of primary buccal mucosa fibroblasts (BMFs). Functional analysis of collagen gel contraction, transwell migration, and wound-healing assays were performed to assess the change in pro-fibrogenic properties of BMFs and fibrotic BMFs (fBMFs). Lentiviral-mediated HDAC9 knockdown was used to verify the role of HDAC9 in the pro-fibrogenic process. ResultsWe found that arecoline significantly increased the mRNA and protein expression of HDAC9 of BMFs in a dose-dependent manner. Knockdown of HDAC9 in BMFs reversed the strengthened effects of arecoline on collagen gel contraction, cell migration, and wound-healing ability. We further demonstrated that knockdown of HDAC9 in fBMFs significantly attenuated its inherent pro-fibrogenic properties. Furthermore, we confirmed a significantly increased expression of HDAC9 mRNA in OSF compared to normal tissues, which suggested a positive correlation between the up-regulation of HDAC9 and OSF. ConclusionWe demonstrated that silencing of HDAC9 inhibited arecoline-induced activation and inherent pro-fibrogenic properties, suggesting potential therapeutics by targeting HDAC9 in the OSF treatment.

Premature ventricular contractions: the role in arterial atherosclerosis pathogenesis

Abstract Funding Acknowledgements Type of funding sources: None. In the list of reasons of atherosclerosis, there are no premature ventricular contractions (PVCs). Purpose To study the main arteries hemodynamics in patients with PVCs and to determine their influence on the atherosclerotic process. Methods We studied 286 patients with PVCs (group 1 (142) – patients with PVCs less 3000 per 24 hours, 2 (144) – more 3000 per 24 hours. Groups were similar in age, gender, comorbidities. By Doppler-ultrasound and shygmography we determined the parameters of heart biomechanics and main arteries kinetics (common carotid, posterior tibial artery): speed, acceleration, power, work in each phase of heart cycle in systole and diastole, the periods of dominance of outflow over inflow. We valued the contribute to the circulation of the PVs and first post-extrasystolic contraction. The volume of cardiac output and transmitral blood flow were measured by echocardiography. We identified the moment of extrasysyoles' appearance by apex-cardiography and ECG. We classified the PVCs up to the moment of their appearance in cardio cycle: before the mitral valve opening; in rapid ventricular filling phase before or after the transmitral blood flow peak; in slow ventricular filling phase; others (group, allorhythmia). Results We identified the following hemodynamic effects of PVCs. 1) The main role in hemodynamic and kinetics changes play the time of PVC’ appearance in cardio cycle and the ability of the first post-extrasystolic contraction to reestablish an adequate resulting blood flow. The maximums of parameters were in first post-extrasystolic contraction in PVCs before the mitral valve opening and before the transmitral peak flow. 2) The prevalence of atherosclerotic process was observed in group 2 (p<0,05). (Carotid bifurcation stenosis hemodynamically not significant in 42 patients in group 2 vs 26 in group 1, significant – 28 vs 8, lower extremities arteries stenoses 37 vs 17, coronary arteries stenoses 74 vs 35, renal arteries stenoses 6 vs 1). 3) Additional stretching of arteries in the first post-extrasystolic pressure wave. It makes conditions for acute and chronic arteries traumatism. 4) Mechanic damage of endothelium and as a result lipid deposition. The "weak places" – are the places of the main effect of the first post-extrasystolic hydraulic shock: aorta arch in large radius, carotid bifurcation, aorta bifurcation. 5) Appearing the stand waves, interferention and diffraction in the places of already existing atheromas. Atheroma is deforming, the integrity of atheroma’s cover is violated and there’re appearing the atheroma’s complications: dissections, wall thrombus of hemodynamically important stenosis. Conclusion PVCs change intra-arterial hemodynamics and can cause the mechanical injury of intima, as well as the injury of existing atherosclerotic plaques that can lead to progressing of atherosclerosis. We suppose to include the PVCs in the list of risk factors of atherosclerosis.