Frontiers in Physiology最新文献

{"title":"A \"thermodynamic\" model of synergistic interaction of human elbow flexor muscles during simultaneous change in their length and force.","authors":"Alexander Kostyukov, Andriy Gorkovenko, Elena Kolosova","doi":"10.3389/fphys.2026.1904516","DOIUrl":"10.3389/fphys.2026.1904516","url":null,"abstract":"<p><strong>Introduction: </strong>Muscle hysteresis reflects nonlinear changes in electromyographic (EMG) activity during isolated changes in the length and force of individual muscles. However, previous studies have primarily considered changes in individual muscle state variables, whereas the hysteresis behavior associated with <i>simultaneous</i> changes in muscle length and force, remains insufficiently understood. Therefore, this study aimed to develop a mathematical model of EMG responses to simultaneous changes in muscle force and length using population-averaged experimental data from the authors' previously published study. Characterizing the history-dependent relationship among muscle activation, force, and length may contribute to adaptive control strategies for robot-aided rehabilitation, with potential applications in the assessment of motor dysfunction and rehabilitation personalization.</p><p><strong>Methods: </strong>A mathematical model was developed to describe the intensity of EMG signals from human elbow flexor muscles during <i>simultaneous</i> changes in muscle force and length. EMG signals and muscle state parameters were obtained from ten participants during a combination of externally controlled joint movements and active force generation under visual biofeedback. The framework of time-averaged derivatives of muscle state parameters was used to derive algorithms for estimating the activation intensity of synergistic muscles during motor tasks.</p><p><strong>Results: </strong>The T-model (\"thermodynamic\" model) was developed based on the functional interdependence of three key parameters: muscle length, force, and the intensity of incoming activation. Algorithms were proposed to predict the activation intensity of synergistic muscles performing motor tasks involving simultaneous changes in muscle force and length. The results show that the use of time-averaged derivatives of muscle state parameters provides a close approximation of central motor commands, with COD values ≥0.9389 across the tested conditions. The analysis demonstrates that the amplitude of hysteresis effects increases with <i>coinciding</i> changes in muscle force and length and decreases when these changes are <i>opposing</i>.</p><p><strong>Conclusion: </strong>The modeling results demonstrate that hysteresis in agonist muscle groups is strongly dependent on the interaction between <i>simultaneous</i> changes in muscle force and length. These findings highlight the importance of considering coupled force-length dynamics in the analysis of neuromuscular control and provide a basis for further applications of muscle hysteresis analysis in motor control and rehabilitation.</p>","PeriodicalId":12477,"journal":{"name":"Frontiers in Physiology","volume":"17 ","pages":"1904516"},"PeriodicalIF":4.3,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13638418/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149107005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reduced serum adiponectin and exercise predict depression in chronic heart failure patients and affect depressive-like behaviors in a mouse model.","authors":"Hui Yang, Qian Du, Fang Zeng, Biao Li","doi":"10.3389/fphys.2026.1835186","DOIUrl":"10.3389/fphys.2026.1835186","url":null,"abstract":"<p><strong>Background: </strong>Chronic heart failure (CHF) is frequently comorbid with depression and anxiety. Currently, we aim to investigate the association between serum adiponectin levels and depression among patients with CHF.</p><p><strong>Methods: </strong>A total of 119 patients with HF in a tertiary hospital in southern China were enrolled. All patients completed the Patient Health Questionnaire-9 (PHQ-9) upon discharge. Serum levels of adiponectin, ghrelin, leptin A, and BDNF were measured. On the basis of PHQ-9 scores, HF patients were divided into non-Dep, mild-Dep, moderate-Dep, and severe-Dep groups. Differences in the levels of cardiac markers and serum mediators between the non/mild-Dep group and the moderate/severe-Dep group were analyzed using weighted univariate and multivariate logistic regression models. An HF C57BL/6 mouse model of depression was established. AdipoRon, an orally active adiponectin receptor agonist, was administered to the mouse model.</p><p><strong>Results: </strong>A total of 119 patients with CHF were categorized into non-Dep (n=35), mild-Dep (n=46), moderate-Dep (n=20), and severe-Dep groups (n=18). Compared with those in the non-Dep group, adiponectin levels in the Dep group were significantly lower and correlated with increased depression severity in HF patients. Weighted univariate and multivariate regression analyses indicated that adiponectin (OR = 0.719; 95% CI: 0.531-0.975) and exercise duration (OR = 0.655; 95% CI: 0.489-0.877) were potential predictors of CHF comorbid with depression. Spearman correlation analysis revealed a positive correlation between adiponectin levels and exercise frequency/duration, whereas negative correlations were found between depression scores and exercise frequency/duration. Sensitivity analyses with stepwise exclusion of high-risk subgroups (diabetes, systemic inflammation, and severe HF) revealed a significant association between exercise duration and depression. In a depression model in MI mice, serum adiponectin levels were decreased. Compared with single-treatment approaches, the combination of adiponectin receptor agonists and exercise intervention effectively improved depressive-like behaviors in mice and regulated related biomarker levels, with superior effects.</p><p><strong>Conclusion: </strong>Reduced serum adiponectin levels and exercise activity were associated with increased odds of having CHF comorbid with depression. Activation of the adiponectin/AdipoR1 pathway combined with exercise intervention has potential benefits for the prevention of depression in patients with HF.</p>","PeriodicalId":12477,"journal":{"name":"Frontiers in Physiology","volume":"17 ","pages":"1835186"},"PeriodicalIF":4.3,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13638401/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149107104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of acute prolonged swimming on skeletal muscle metabolism in different muscle types of rats after nine days of dexamethasone treatment.","authors":"Damian Jozef Flis, Bartosz Cedro, Alicja Piekarska, Andzelika Borkowska, Malgorzata Halon-Golabek, Ewa Rodziewicz-Flis, Jedrzej Antosiewicz, Wieslaw Ziolkowski","doi":"10.3389/fphys.2026.1890376","DOIUrl":"10.3389/fphys.2026.1890376","url":null,"abstract":"<p><strong>Objectives: </strong>The study investigated the effec of dexamethasone (Dex) treatment, acute prolonged swimming, and their combination on skeletal muscle mass, oxidative stress, iron metabolism, and AKT-mediated signaling in two muscle types.</p><p><strong>Methods: </strong>Rats were divided into four groups (n=8 per group): intraperitoneal saline or Dex (1mg/kg/day) treatment for 9 days (non-exercised and exercised). Animals in exercise groups underwent a 4-day preparatory swimming procedure followed by a single 3h swimming session. The soleus (SOL) and extensor digitorum longus (EDL) muscles were collected, weighed, and used for analysis. We assessed lipid and protein peroxidation markers, catalase activity, iron-metabolism proteins, and AKT-dependent proteolysis and synthesis pathways.</p><p><strong>Results: </strong>Nine days of Dex treatment significantly reduced SOL (-12%, p<0.01) and EDL (-15%, p<0.001) mass, accompanied by oxidative stress (increased protein peroxidation, p<0.001) and alterations in iron metabolism: increased FH (SOL: +88%, p<0.01, EDL: +80%, p<0.01) and decreased PCBP1 (SOL: -59%, p<0.001, EDL: -33%, p<0.05). Dex treatment also affected proteins involved in synthesis and proteolysis pathways: in SOL, lowered total AKT (-22%, p<0.05) and pmTOR (-24%, p<0.05); in EDL, decreased MuRF-1 (-30%, p<0.01) and total mTOR (-24%, p<0.01), highlighting mechanisms underlying muscle loss. In saline-treated rats, acute prolonged swimming, following 4 days of preparatory exercise, did not affect SOL and EDL mass or oxidative stress markers. However, in SOL, swimming reduced PCBP1 (-43%, p<0.001), decreased total AKT (-33%, p<0.01) and pAKT (-47%, p<0.01), increased Atrogin-1 levels (+38%, p<0.001), and decreased pmTOR (-52%, p<0.001) and p70S6K levels (-47%, p<0.05). In EDL, swimming lowered MuRF-1 levels (-23%, p<0.01), indicating specific responses to exercise across muscle types. Dex-induced muscle mass loss was lower after a 4-day preparatory exercise procedure followed by prolonged exercise (p<0.001 for both muscles). Swimming in Dex-treated rats decreased pAKT (-52%, p<0.01) in SOL and increased pmTOR (+52%, p<0.01) in EDL.</p><p><strong>Conclusion: </strong>Dex treatment reduces skeletal muscle mass, regardless of fiber composition. These changes relate to oxidative stress and an imbalance in iron metabolism, but differences between muscle types in the proteolysis/synthesis signaling pathway highlight contrasting responses across muscle types. Acute prolonged swimming, preceded by a 4-day preparatory procedure, attenuates the adverse effects of Dex treatment.</p>","PeriodicalId":12477,"journal":{"name":"Frontiers in Physiology","volume":"17 ","pages":"1890376"},"PeriodicalIF":4.3,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13638438/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149106524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of carbon dioxide hydrate cryotherapy on knee flexor muscle function recovery trajectory after muscle damage: a randomized controlled trial.","authors":"Rina Watabe, Daigo Shiozaki, Kohei Ono, Kosuke Hirata, Ryota Akagi","doi":"10.3389/fphys.2026.1924770","DOIUrl":"10.3389/fphys.2026.1924770","url":null,"abstract":"<p><strong>Introduction: </strong>This study investigated the effects of carbon dioxide hydrate (CDH) cryotherapy on the recovery trajectories of muscle function and physiological markers following exercise-induced muscle damage (EIMD) of the knee flexors.</p><p><strong>Methods: </strong>In a randomized parallel-group design, 24 young men were assigned to the CDH, conventional icing (ICE), or non-intervention control (CON) group (n = 8 per group). To induce muscle damage, participants performed 10 sets of eight maximal eccentric contractions of the knee flexors in a prone position (knee joint range: 75°-15° of flexion at 60°/s; 0° = the fully extended anatomical position). Maximal voluntary isometric contraction (MVIC) torque of the knee flexors was measured at 30° of knee flexion at baseline (PRE), immediately post-exercise (POST), and at 4.5, 24, 48, 72, and 168 h post-exercise. Secondary outcomes, including thigh circumference, hip joint range of motion (ROM), and hamstring muscle stiffness and pressure-induced soreness were assessed at all time points except POST. A 20-min intervention was administered after each assessment from POST to 72 h.</p><p><strong>Results: </strong>Linear mixed-effects models, adjusted for PRE values, revealed no significant group × time interactions for changes from PRE in any outcome across post-exercise time points (POST to 168 h for MVIC torque; 4.5 to 168 h for secondary outcomes; <i>p</i> = 0.177-0.914). A significant main effect of group was observed only for hip joint ROM (<i>p</i> = 0.039). <i>Post-hoc</i> comparisons revealed a significantly greater overall reduction from PRE in the CDH group than in the CON group (difference: 10.3°, 95% CI: 3.0° to 17.6°, <i>p</i> = 0.017), with no significant differences between the other group pairs (both <i>p</i> = 0.131). Given the multi-outcome testing, this isolated effect should be interpreted as exploratory.</p><p><strong>Conclusion: </strong>Under the present experimental conditions, CDH cryotherapy did not accelerate the recovery of muscle function or attenuate secondary markers following EIMD relative to conventional icing or no intervention.</p>","PeriodicalId":12477,"journal":{"name":"Frontiers in Physiology","volume":"17 ","pages":"1924770"},"PeriodicalIF":4.3,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13638424/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149106938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unsupervised learning-based optimization of college students' fundamental capacity evaluation method.","authors":"Lei Jiang, Jinxi Zhang, Youwei Zhang, Yanan Gao, Rufeng Su, Zhixiong Zhou","doi":"10.3389/fphys.2026.1921534","DOIUrl":"10.3389/fphys.2026.1921534","url":null,"abstract":"<p><strong>Background: </strong>The Fundamental Capacity Screen (FCS) is a standardized method for assessing athletic performance and fundamental capacity (FC). However, its current framework lacks refinement, yielding qualitative and insufficiently detailed results that hinder precise athletic training and performance evaluation.</p><p><strong>Objective: </strong>This study employs unsupervised learning to refine FC evaluation, enhancing its objectivity and scientific rigor by providing a more data-driven and interpretable approach.</p><p><strong>Methods: </strong>Data from 123 college students (61 males, mean age 20.42 ± 1.88 years; 62 females, mean age 20.35 ± 1.85 years) regarding FC test indicators were initially subjected to a factor analysis (FA) model to identify underlying factors. Hierarchical clustering was then performed on the first factor. Based on these results, relevant rules of abilities were established, and principal component analysis (PCA) was employed to reduce the dimensionality of multidimensional indicators. Finally, the entropy weight method was used to calculate and adjust the scores of each ability, and the scores were summarized and classified by percentile.</p><p><strong>Results: </strong>FA revealed 3 distinct factors (jumping ability, upper limb ability, and lower limb ability) that together explained 0.8569 of the total variance. The hierarchical clustering dendrogram indicated that jumping ability could be further subdivided. Based on this, 5 ability categories were defined: upper limb balance control, lower limb balance control, core-mediated transfer control, explosive control, and impact control. The composite scores were categorized into 5 intervals: poor, pass, good, excellent, and outstanding. The depicted radar map shows the median characteristics of the composite scores of different abilities.</p><p><strong>Conclusions: </strong>Results demonstrate that unsupervised learning provides a more intuitive and objective framework for FC assessment, offering a novel perspective for athletic performance evaluation and training optimization.</p>","PeriodicalId":12477,"journal":{"name":"Frontiers in Physiology","volume":"17 ","pages":"1921534"},"PeriodicalIF":4.3,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13640604/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149106718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kaempferol ameliorates gestational diabetes mellitus by regulating STAT3-associated AIM2 inflammasome activation and ferroptotic injury in trophoblasts.","authors":"Ronghui Liu, Qiqi Liu, Lanjie Yi","doi":"10.3389/fphys.2026.1857741","DOIUrl":"10.3389/fphys.2026.1857741","url":null,"abstract":"<p><strong>Introduction: </strong>To investigate the protective effects of kaempferol (KPF) against gestational diabetes mellitus (GDM) and elucidate its underlying molecular mechanisms.</p><p><strong>Methods: </strong>A GDM rat model was established to assess metabolic abnormalities, inflammation, oxidative stress, and placental injury following KPF treatment. <i>In vitro</i>, high glucose (HG)-stimulated HTR-8/SVneo trophoblast cells were used to investigate the protective mechanisms of KPF. Mitochondrial dysfunction, lipid peroxidation, ferroptosis-related alterations, and AIM2 inflammasome activation were evaluated. STAT3 knockdown and AIM2 overexpression were further performed to determine their roles in HG-induced trophoblast injury.</p><p><strong>Results: </strong>KPF significantly improved glucose and lipid metabolism, reduced inflammatory cytokine levels, alleviated placental injury, and decreased oxidative stress in GDM rats. In HG-stimulated trophoblasts, KPF attenuated mitochondrial dysfunction, lipid peroxidation, and ferroptosis-related alterations by restoring GPX4 and SLC7A11 expression and inhibiting AIM2 inflammasome activation. Mechanistically, KPF suppressed STAT3 activation, while STAT3 knockdown reduced STAT1/IRF1 activation and AIM2 expression under hyperglycemic conditions. AIM2 overexpression aggravated ferroptosis-related changes and inflammatory responses.</p><p><strong>Conclusion: </strong>KPF alleviates GDM-associated placental dysfunction by modulating STAT3-associated signaling and AIM2 inflammasome activation, thereby reducing ferroptosis-related injury and inflammatory activation in trophoblasts. These findings provide new insights into the mechanisms of GDM and support KPF as a potential therapeutic candidate.</p>","PeriodicalId":12477,"journal":{"name":"Frontiers in Physiology","volume":"17 ","pages":"1857741"},"PeriodicalIF":4.3,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13640141/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149107069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-exposure effects of simulator sickness in motion-based flight simulators: a review of symptom duration and implications for flight fitness.","authors":"Nico Willebrand Genannt Overgahr, David Feibus, Stefan Sammito","doi":"10.3389/fphys.2026.1848400","DOIUrl":"https://doi.org/10.3389/fphys.2026.1848400","url":null,"abstract":"<p><strong>Introduction: </strong>The increasing use of modern motion-based flight simulators in military and civil aviation, despite their high relevance for training, is accompanied by the occurrence of simulator sickness. While acute symptoms during simulation are well described, the duration of post-exposure complaints and their significance for subsequent real flight capability have not yet been sufficiently investigated. The aim of this exploratory review was to summarise the available studies on the (persistence of) symptoms after flight-related simulator training.</p><p><strong>Methods: </strong>A systematic literature search was conducted in PubMed, Web of Science and Scopus in accordance with PRISMA guidelines. From a total of 4,404 hits, 14 full texts were included in this review.</p><p><strong>Results: </strong>The studies showed considerable heterogeneity in terms of participants, simulator types, exposure duration and measuring instruments. Typical symptoms included eye strain, nausea, disorientation and, less frequently, dizziness and fatigue. Only a few studies systematically investigated after-effects beyond the immediate period following the simulation. The limited available data suggest that most complaints subside significantly within four to six hours, although individual cognitive and postural impairments may persist for longer. It is currently not possible to make reliable statements about the objective restoration of flight fitness or an evidence-based minimum waiting period between simulator training and actual flight.</p><p><strong>Discussion: </strong>Overall, there is a considerable need for research, particularly using modern full-motion simulators and standardised objective performance parameters, for deriving valid safety-related recommendations and examining symptom decay.</p><p><strong>Systematic review registration: </strong>https://www.crd.york.ac.uk/PROSPERO/, identifier CRD420251161357.</p>","PeriodicalId":12477,"journal":{"name":"Frontiers in Physiology","volume":"17 ","pages":"1848400"},"PeriodicalIF":4.3,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13634811/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149107081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sublethal cadmium exposure disrupts cardiac function and tissue structure in zebrafish larvae.","authors":"Alexander Machikhin, Anastasia Guryleva, Viacheslav Krylov, Valeriya Bukova, Artem Slavin, Leonid Shuman, Alexander Selyukov, Alexander Burlakov, Anirban Chakraborty","doi":"10.3389/fphys.2026.1865285","DOIUrl":"https://doi.org/10.3389/fphys.2026.1865285","url":null,"abstract":"<p><p>Cadmium remains a primary toxicological concern because it does not degrade and easily enters the food chain, affecting diverse ecosystems. This study aimed to evaluate the effects of sublethal cadmium exposure on cardiac function and on brain and heart tissues in zebrafish (<i>Danio rerio</i>) larvae, utilizing photoplethysmography as a rapid, non-invasive approach. Larvae (1 day post-hatching) were exposed for five days to cadmium sulfate at concentrations of 0.005, 0.025, and 0.05 mg/L under controlled laboratory conditions. Cardiac activity was assessed twice a day using a non-invasive photoplethysmography-based technique. Histological analyses of brain and heart tissues were conducted using standard fixation, sectioning, and staining protocols. At the highest cadmium concentration, histological examination revealed neuronal degeneration in brain tissue and thinning of the cardiac wall. Cadmium exposure led to heart rate suppression, with the most pronounced effect observed at 0.05 mg/L. Lower concentrations exhibited attenuated but still significant effects compared to controls. These findings indicate that cadmium exerts both functional and structural toxicity in zebrafish larvae, affecting cardiovascular development and neural integrity. The results support the use of heart rate, measured via photoplethysmography, as a sensitive and non-invasive endpoint for detecting sublethal cardiotoxic effects.</p>","PeriodicalId":12477,"journal":{"name":"Frontiers in Physiology","volume":"17 ","pages":"1865285"},"PeriodicalIF":4.3,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13634864/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149107098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alterations in corticospinal excitability in individuals with ankle sprains: a systematic review of transcranial magnetic stimulation studies.","authors":"Yanli Chen, Mengyu Li, Songlin Xiao","doi":"10.3389/fphys.2026.1951700","DOIUrl":"https://doi.org/10.3389/fphys.2026.1951700","url":null,"abstract":"<p><strong>Objective: </strong>This study aimed to systematically review the literature on corticospinal excitability in individuals with ankle sprains.</p><p><strong>Methods: </strong>This systematic review adhered to the guidelines established by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A systematic search was performed on PubMed, SPORTDiscus, and Web of Science. Studies were included according to the Participants, Intervention, Comparison, Outcomes, and Setting inclusion criteria.</p><p><strong>Results: </strong>The electronic search yielded 233 studies, of which eleven studies were included after careful screening. Eight of the nine studies consistently reported reduced corticospinal excitability of several lower limb muscles in chronic ankle instability (CAI). Two studies identified an elevated motor evoked potential in cases of acute lateral ankle sprain.</p><p><strong>Conclusions: </strong>CAI exhibits lower corticospinal excitability and high cortical inhibitory activity. Individuals with acute ankle sprain exhibit increased corticospinal excitability, which be presented cautiously as a preliminary finding requiring further confirmation. This review offers a theoretical basis for revealing potential changes in spinal cord segmental activities after ankle sprains, suggesting that altered corticospinal excitability may associate with impaired sensorimotor function and represents a potential target for future rehabilitation research.</p>","PeriodicalId":12477,"journal":{"name":"Frontiers in Physiology","volume":"17 ","pages":"1951700"},"PeriodicalIF":4.3,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13634940/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149106974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enabling artificial placenta cannulation: mechanisms of postnatal umbilical vessel closure and strategies to prolong patency.","authors":"Nils B Römer, Sjoerd Haalstra, Danny J M van Galen, Daan R M G Ophelders, G Adrienne Weiss, Jan Däbritz, Tim G A M Wolfs, Jutta Arens, Christoph Fusch, Niels Rochow","doi":"10.3389/fphys.2026.1928360","DOIUrl":"https://doi.org/10.3389/fphys.2026.1928360","url":null,"abstract":"<p><p>Umbilical vessel closure after birth prevents hemorrhage but limits the time window for large-bore umbilical cannulation required for artificial placenta support. This review synthesizes physiologic triggers, vasoactive pathways, and vessel-wall specializations that drive rapid postnatal occlusion and highlights engineering-relevant targets to prolong functional patency. Umbilical vessel closure is promoted by the transition to extrauterine life (cooling, rising oxygen tension, oxidative stress, loss of placental vasodilator influence), altered hemodynamics after lung aeration, and mechanical stimulation of the cord. At the molecular level, vasoconstriction is driven by redundant mediator networks-most prominently serotonin and thromboxane A₂, with supportive contributions from endothelin-1, acetylcholine, bradykinin, catecholamines, and histamine-occurring in the context of limited vasorelaxation capacity. Structurally, the umbilical arteries exhibit a distinctive bilayered tunica media: an outer contractile smooth-muscle-rich layer and an inner proteoglycan-rich layer prone to inward buckling, supported by longitudinal intimal protrusions (Folds of Hoboken) that further promote mechanical occlusion of the lumen. Together, these features form a robust \"fail-safe\" closure program, although the specific mechanisms governing the intra-abdominal segments remain less understood.</p>","PeriodicalId":12477,"journal":{"name":"Frontiers in Physiology","volume":"17 ","pages":"1928360"},"PeriodicalIF":4.3,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13635895/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149107097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}