Journal of applied physiology最新文献

{"title":"Effect of 12 weeks of interval training on skeletal muscle blood flow during single-leg knee extensor exercise in COPD: a nonrandomized controlled trial.","authors":"Jacob P Hartmann, Stine Buus Nymand, Helene Louise Hartmeyer, Camilla Koch Ryrsø, Amalie B Andersen, Milan Mohammad, Iben Elmerdahl Rasmussen, Rie Skovly Thomsen, Cody Garett Durrer, Ronan M G Berg, Ulrik Winning Iepsen","doi":"10.1152/japplphysiol.00798.2024","DOIUrl":"10.1152/japplphysiol.00798.2024","url":null,"abstract":"<p><p>High-intensity interval training (HIIT) has shown to improve exercise capacity, symptom burden, and quality of life in patients with chronic obstructive pulmonary disease (COPD), but it remains to be investigated if HIIT can counteract limb muscle dysfunction. Therefore, we examined the impact of a 12-wk supervised HIIT protocol on muscle oxygen conductance. Eight patients with mild-to-moderate COPD and eight age-, sex-, and BMI-matched controls underwent a 12-wk HIIT intervention. Leg blood flow ([Formula: see text]) and arterio-venous blood samples were collected at rest and during active single-leg knee-extensor exercise (KEE) at unloaded (0 W) and 20% of peak workload (W_Lpeak) to estimate leg muscle oxygen conductance pre- and post-HIIT. In pre-HIIT, [Formula: see text] was similar between groups during unloaded KEE (<i>P</i> = 0.108) but lower at 20% W_Lpeak in the COPD group, compared with the control group. [Formula: see text] responses were higher during unloaded KEE (28%, <i>P</i> = 0.012) and 20% W_Lpeak (40%, <i>P</i> < 0.001) post-HIIT in the COPD group, whereas no change occurred in the control group. Flow-adjusted skeletal muscle O₂ conductance was higher in the COPD pre-HIIT group but only increased in the control group. Thus, there was no difference in diffusive or convective capacity between groups post-HIIT at submaximal KEE. COPD assessment score decreased by 2.8 [1;4] (<i>P</i> = 0.003) in the COPD group and V̇o_2peak increased in both groups (COPD 192 mL O₂/min, <i>P</i> = 0.032, control 257 mL O₂/min, <i>P</i> = 0.004) with no time/group interaction. A 12-wk HIIT intervention may improve peripheral exercise capacity in COPD by increasing the vasodilatory function in working muscle while concurrently improving whole-body exercise capacity and symptom burden.<b>NEW & NOTEWORTHY</b> Individuals with COPD exhibit lower blood flow to the exercising leg muscles, which may be considered part of the limb muscle dysfunction associated with the disease. A 12-wk high-intensity interval training (HIIT) program increased leg blood flow in patients with COPD during single-leg knee extensor exercise achieved by improving the vasodilatory response. HIIT also improved maximal oxygen uptake and exercise capacity while reducing symptom burden.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"836-847"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143492192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oral contraceptive pill phase does not influence muscle protein synthesis or myofibrillar proteolysis at rest or in response to resistance exercise.","authors":"Lauren M Colenso-Semple, James McKendry, Changhyun Lim, Philip J Atherton, Daniel J Wilkinson, Kenneth Smith, Stuart M Phillips","doi":"10.1152/japplphysiol.00035.2025","DOIUrl":"10.1152/japplphysiol.00035.2025","url":null,"abstract":"<p><p>There is speculation that the use of oral contraceptive pill (OCP) affects skeletal muscle biology and protein turnover in response to resistance exercise; however, research in this area is scarce. We aimed to assess, using stable isotope tracers and skeletal muscle biopsies, how second-generation OCP phase affected muscle protein synthesis and whole body proteolysis. Participants (<i>n</i> = 12) completed two 6-day study phases in a randomized order: an active pill phase (active; <i>week 2</i> of a monthly active OCP cycle) and an inactive pill phase (inactive; final week of a monthly OCP cycle). They performed unilateral resistance exercise in each study phase, exercising the contralateral leg in the opposite phase in a randomized, counterbalanced order. The active phase myofibrillar protein synthesis (MPS) rates were 1.44 ± 0.14%·day^-1 in the control leg and 1.64 ± 0.15%·day^-1 in the exercise leg (<i>P</i> < 0.001). The inactive phase MPS rates were 1.49 ± 0.12%·day^-1 in the control leg and 1.71 ± 0.16%·day^-1 in the exercise leg (<i>P</i> < 0.001), with no interaction between phases (<i>P</i> = 0.63). There was no significant effect of OCP phase on whole body myofibrillar proteolytic rate (active phase <i>k</i> = 0.018 ± 0.01; inactive phase <i>k</i> = 0.018 ± 0.006; <i>P</i> = 0.55). Skeletal muscle remains equally as responsive, in terms of stimulation of MPS, during active and inactive OCP phases; hence, our data do not support a proanabolic or catabolic, based on myofibrillar proteolysis, effect of OCP phase on skeletal muscle in females.<b>NEW & NOTEWORTHY</b> We discovered that women taking a second-generation oral contraceptive pill (OCP) showed no difference in integrated daily muscle protein synthesis or whole body myofibrillar proteolysis in the active or placebo pill phases of the pill cycle. Our data show that OCP phase neither influences skeletal muscle protein turnover in females and nor supports a marked procatabolic or anabolic effect.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"810-815"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143515700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Postpartum dams exposed to a low-resource environment display neuroinflammation, elevated corticosterone, and anhedonia-like behavior.","authors":"Kylie Jones, Savanna Smith, Jonna Smith, Angie Castillo, Allison Burkes, Ahfiya Howard, Madison M Garvin, Jessica L Bolton, Luis Colon-Perez, Mark W Cunningham","doi":"10.1152/japplphysiol.00871.2024","DOIUrl":"10.1152/japplphysiol.00871.2024","url":null,"abstract":"<p><p>Women living in an impoverished environment after birth have an increased risk of developing postpartum depression (PP-Dep) and hypertension (PP-HTN). The mechanisms underlying these heightened risks are unknown and understudied. To examine the relation between reduced environmental resources, PP-Dep, and PP-HTN, postpartum rodent dams were exposed to the low-resource limited bedding and nesting (LBN) chronic stress model during weaning. Postpartum dams were divided into control (CTL) and experimental (LBN) groups, in which the experimental group experienced LBN. At 6 wks postpartum, blood pressure, sucrose preference tests (a proxy for anhedonia and depression), corticosterone, and markers of neuroinflammation were measured. We hypothesized that postpartum dams exposed to LBN will have increased corticosterone, neuroinflammation, depression-like behaviors, and HTN. Results show that postpartum dams exposed to an impoverished environment exhibit decreased sucrose preference, increased circulating corticosterone, and elevated neuroinflammation (∼150% increased TNF-α and astrocyte activation in the cerebrum). No changes in blood pressure were observed. However, there was a strong correlation between postpartum blood pressure and corticosterone and blood pressure and TNF-α levels. Importantly, this study provides insights into the pathology and development of PP-HTN and PP-Dep in the postpartum period, which will enable the discovery of novel therapeutic approaches.<b>NEW & NOTEWORTHY</b> Postpartum dams exposed to a low-resource environment experience anhedonia, elevated corticosterone, and neuroinflammation. Increases in corticosterone and neuroinflammation may contribute to the development of postpartum depression (PP-Dep) and postpartum hypertension (PP-HTN). Healthcare providers should consider asking questions about the social economic status and accessibility of resources for women after pregnancy. This study advocates for extended postpartum care beyond traditional care and better implementation of assessments for PP-Dep and PP-HTN.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"666-680"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143065884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Responses of skeletal muscle to mechanical stimuli in female rats following and during muscle disuse atrophy.","authors":"Alexander B Sklivas, Zachary R Hettinger, Sarah Rose, Alessandra Mantuano, Amy L Confides, Sandra Rigsby, Frederick F Peelor, Benjamin F Miller, Timothy A Butterfield, Esther E Dupont-Versteegden","doi":"10.1152/japplphysiol.00802.2024","DOIUrl":"10.1152/japplphysiol.00802.2024","url":null,"abstract":"<p><p>The purpose of this study was to investigate the ability of mechanotherapy to enhance recovery or prevent loss of muscle size with disuse in female rats. Female F344/BN rats were assigned to weight bearing (WB), hindlimb suspended (HS) for 14 days with reambulation for 7 days without mechanotherapy or reambulation (RA) with mechanotherapy (RAM) (<i>study 1</i>), or to WB, HS for 7 days, with HS mechanotherapy (HSM) or without mechanotherapy (<i>study 2</i>) to gastrocnemius muscle. Muscle fiber cross-sectional area (CSA) and fiber type, collagen, satellite cell number, and protein synthesis (<i>k</i>_syn) and degradation (<i>k</i>_deg) were assessed. <i>Study 1</i>: muscle weight, but not CSA, was higher in RAM compared with HS, but CSA was higher in RA compared with HS. Myofibrillar <i>k</i>_syn was higher in RA and RAM compared to WB and HS but not different between RA and RAM. Myofibrillar <i>k</i>_deg was lower with mechanotherapy compared to HS. <i>Study 2</i>: muscle weight, CSA, and myofibrillar <i>k</i>_syn and <i>k</i>_deg were not different with mechanotherapy. Collagen content was lower with mechanotherapy but collagen <i>k</i>_syn was not. Mechanotherapy was not associated with changes in fiber type, satellite cell, or myonuclear number in either study. Compared to males, female rats had less muscle loss with HS, which was associated with less loss of myofibrillar <i>k</i>_syn. Recovery from atrophy was associated with higher <i>k</i>_syn in female and lower <i>k</i>_deg in male rats. Female rat muscles do not exhibit a growth response to mechanotherapy with disuse or reambulation. Furthermore, male and female rats show distinct responses to different mechanical stimuli.<b>NEW & NOTEWORTHY</b> This study investigates the response of female rats to mechanical stimulation in both active and passive forms following and during muscle disuse atrophy. New findings indicate that female rats respond to active loading with enhanced muscle regrowth and protein synthesis, whereas passive loading using mechanotherapy did not affect atrophy or recovery of female muscles. Comparison with published data indicates that there are distinct differences in male and female rats in their response to mechanical stimuli.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"652-665"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143065891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regional lung volume changes with noninvasive positive pressure ventilation in healthy adults.","authors":"D Karmali, S Afanador-Castiblanco, T Ötvös, G Aguilar, S Hossen, N Eikelis, K Nilsen, N M Punjabi, T Siddharthan, J P Kirkness","doi":"10.1152/japplphysiol.00676.2024","DOIUrl":"10.1152/japplphysiol.00676.2024","url":null,"abstract":"<p><p>Noninvasive assessments of lung volume distribution often require inhaled contrast and are limited by low regional resolution. We aimed to examine a noncontrast imaging method of spatial lung volume displacement, adapted to assess changes with noninvasive positive pressure ventilation (NIPPV). This study evaluated regional lung volume displacement in nine healthy volunteers (6 males and 3 females; ages 29-55 yr; body mass index 20.2-31.3 kg/m²) using X-ray velocimetry (XV). Participants were assessed during tidal breathing and, also with 15 cmH₂O inspiratory and 5 cmH₂O expiratory pressures in a supine position. Regional specific ventilation (SV) was measured during tidal breathing and NIPPV. Mean specific ventilation (MSV, mL/mL), low-volume region (LVR; % < 0.1 mL/mL), and high-volume region (HVR; % > 0.3 mL/mL) were calculated as output variables. Images were segmented into lobar as well as central and peripheral zones. Two-way ANOVA and paired <i>t</i> tests were used to determine regional differences within individuals and the effect of NIPPV. NIPPV increased MSV in both peripheral (<i>P</i> = 0.01) and central (<i>P</i> = 0.02) lung regions compared with tidal breathing. High-volume regions increased in both peripheral (<i>P</i> = 0.04) and central regions (<i>P</i> = 0.04) during NIPPV. This study demonstrates that noncontrast imaging techniques can assess regional lung ventilation and redistribution of lung volumes on NIPPV. Heterogeneous responses to NIPPV may be associated with a distinct distribution of ventilation, and further work is needed to ascertain differential responses to NIPPV due to lung pathology among those with respiratory disease.<b>NEW & NOTEWORTHY</b> Noninvasive positive pressure ventilation (NIPPV) is a commonly utilized intervention for acute and chronic respiratory failure. In this study, we use functional lung imaging to describe changes in regional lung ventilation and redistribution of lung volume with NIPPV. These results offer insight into the regional effects of NIPPV on volume expansion with the use of functional imaging.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"731-738"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143408103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cardiac dilation, energy stress, and ventricular remodeling: insights from prolonged voluntary exercise in male mice with TAC-induced HFpEF.","authors":"Yanna Liu, Li Wang, Sirui Jiao, Xiaohan Yang, Gang Liu, Kai Fan, Henan Zhao, Jianmei Ma","doi":"10.1152/japplphysiol.00275.2024","DOIUrl":"10.1152/japplphysiol.00275.2024","url":null,"abstract":"<p><p>Exercise in heart failure with preserved ejection fraction (HFpEF) remains a hot topic, although current treatment strategies have not been shown to improve the long-term prognosis of HFpEF. Previous studies have mostly focused on the roles of endurance training; the mechanisms underlying long-term voluntary exercise have not been elucidated. The purpose of the present analysis was to evaluate alterations in cardiac function in HFpEF mice (HFpEF-Sed) after 6 wk of voluntary running (HFpEF-Ex), investigate mechanisms, and compare the effects with fluoxetine (HFpEF-FLX). We found that voluntary exercise, instead of fluoxetine intervention, significantly improved left ventricular end-diastolic internal diameter (LVIDd) and the rate of change in anterior wall thickness (AWT) in HFpEF mice. The exercise capacity of HFpEF-Sed mice was significantly reduced, but prolonged voluntary running significantly reversed the expression of myocardial brain natriuretic peptide (BNP), TNF-α, and IL-6, α-myosin heavy chain (α-MHC), and β-MHC in HFpEF-Sed mice, along with myocardial fiber disorders accompanied by massive inflammatory cell infiltrates. Importantly, myocardial complex III and complex V, Mfn2, Drp1, p62, and LC3 II/I expression in HFpEF-Sed mice were all significantly different from those of normal mice, whereas voluntary exercise significantly reversed these expressions. These findings strongly suggest that long-term voluntary exercise is effective in avoiding acute and chronic energy stress in HFpEF-Sed mice, which is consistent with the mechanism of current first-line treatment for HFpEF. This notion was further supported by electron microscopy results, which showed no pathological features in cardiomyocyte mitochondrial morphology after prolonged voluntary exercise. In addition, fluoxetine was found to inhibit depressive-like behavior in HFpEF mice.<b>NEW & NOTEWORTHY</b> As a self-initiating, self-sustaining, and low-cost treatment for patients with heart failure, how voluntary exercise plays its roles in interfering with the pathophysiologic pathways associated with HFpEF is still largely unknown. The results of this study indicate that long-term voluntary exercise can effectively antagonize acute and chronic dual-energy stress and avoid diastolic function limitation caused by pathological ventricular remodeling.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"746-760"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143052640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of work intensity on acute kidney injury risk during simulated occupational heat stress.","authors":"Hayden W Hess, Molly E Heikkinen, Erica Tourula, M Jo Hite, Kelli Rivers, Roger S Zoh, Blair D Johnson, David Hostler, Zachary J Schlader","doi":"10.1152/japplphysiol.00590.2024","DOIUrl":"10.1152/japplphysiol.00590.2024","url":null,"abstract":"<p><p>Violation of the National Institute of Occupational Safety and Health (NIOSH) heat stress recommendations by exceeding the allowable wet bulb globe temperature (WBGT) for a given work intensity and work-rest ratio augments acute kidney injury (AKI) risk. Here, we tested the hypothesis that exceeding the allowable work intensity at a given WBGT and work-rest ratio would also worsen AKI risk. Twelve healthy adults completed two NIOSH recommendation compliant trials and one noncompliant trial consisting of a 4 h (half workday) exposure. Work-rest ratio was fixed at 30 min of walking and 30 min of rest each hour. Work intensity (metabolic heat production) was prescribed as a function of WBGT-412 ± 51 W [27.3 ± 0.3°C; high-intensity compliant (C_high)], 290 ± 75 W [31.6 ± 0.2°C; low-intensity compliant (C_low)], and 410 ± 61 W [31.7 ± 0.2°C; high-intensity noncompliant (NC_high)]. AKI risk was quantified by the product of urinary insulin-like growth factor-binding protein 7 and tissue inhibitor of metalloproteinase 2 normalized to urine specific gravity ([IGFBP7·TIMP-2]_USG). Peak core temperature was higher in NC_high trial (38.3 ± 0.4°C) compared with the compliant trials (C_high: 38.0 ± 0.3°C; C_low: 37.8 ± 0.4°C; <i>P</i> ≤ 0.0095). [IGFBP7·TIMP-2]_USG increased from pre- to immediately postexposure in all trials (time effect: <i>P</i> = 0.0454) but the peak increase was not different between trials [C_high: 0.89 ± 1.7 (ng/mL)²/1,000; C_low: 0.78 ± 1.7 (ng/mL)²/1,000; NC_high: 1.0 ± 1.4 (ng/mL)²/1,000; <i>P</i> = 0.7811]. Violating the NIOSH recommendations by exceeding either the allowable work intensity (i.e., NC_high vs. C_low) or WBGT (i.e., NC_high vs. C_high) resulted in a modest elevation in peak core temperature but did not modify AKI risk.<b>NEW & NOTEWORTHY</b> We demonstrate that violation of the National Institute for Occupational Safety and Health heat stress recommendations by exceeding allowable work intensity by ∼120 W or environmental limits by ∼4°C wet bulb globe temperature (WBGT) at 30-min work-rest per hour results in a modest elevation in peak core temperature but does not augment acute kidney injury risk compared with scenarios that adhered to the NIOSH recommendations during simulated occupational heat stress.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"706-717"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143039002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alterations in the intersegmental coordination of landing from a jump in a microgravity environment.","authors":"Thibaut D Toussaint, Jean-Matthieu Pypaert, Clément N Gambelli, Bénédicte Schepens","doi":"10.1152/japplphysiol.00511.2024","DOIUrl":"10.1152/japplphysiol.00511.2024","url":null,"abstract":"<p><p>The objective is to investigate the intersegmental coordination during landing from a countermovement jump in different gravitational environments to gain insight on how humans perceive gravity and coordinate complex motor tasks. Eight participants performed countermovement jumps on Earth (1 <i>g</i>) and while submitted to four simulated gravity levels (from 0.2 to 1 <i>g</i>) generated by a downward pull-down force in weightlessness induced by parabolic flights. The orientation of body segments (i.e., elevation angles) was recorded using a high-speed camera. A principal component analysis was performed on the elevation angles of the foot, shank, thigh, and trunk segments together with a correlation analysis. Regardless of the environment, the movements of the four body segments are tuned through a law of intersegmental coordination; the vertical position of the center of mass of the body being identified as the parameter controlled. The movement of the foot seems an independent factor, given its minimal contribution to the intersegmental coordination and the poor correlation with the shank segment. In weightlessness, the intersegmental coordination is less unidimensional and more variable compared with Earth's gravity. In addition, the lower the gravity level simulated in weightlessness, the greater the contribution of the foot and of the shank, and the lower the contribution of the thigh, suggest an adjustment of the intersegmental coordination through a reweighting of altered sensory inputs. In conclusion, the intersegmental coordination remains better optimized for Earth gravity, but the unidimensional synergy is preserved in weightlessness when using a downward pull-down force to simulate gravity.<b>NEW & NOTEWORTHY</b> During landing, the movements of the trunk, thigh, shank, and foot are tuned through a unidimensional synergy, identified as the vertical position of the center of mass. In microgravity, the coordination is overall less unidimensional and more variable compared with Earth's gravity, suggesting a suboptimal coordination. In lower microgravity levels, greater contribution of the foot and of the shank, and lower contribution of the thigh suggest an adjustment through a reweighting of sensory inputs.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"848-856"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143523411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combining hyperpolarized ¹²⁹Xe MR imaging and spectroscopy to noninvasively estimate pulmonary vascular resistance.","authors":"Anna Costelle, Junlan Lu, Suphachart Leewiwatwong, Berend Westerhof, David Mummy, Sudarshan Rajagopal, Bastiaan Driehuys","doi":"10.1152/japplphysiol.00440.2024","DOIUrl":"10.1152/japplphysiol.00440.2024","url":null,"abstract":"<p><p>Hyperpolarized ¹²⁹Xe MRI/MRS enables quantitative mapping of function in lung airspaces, membrane tissue, and red blood cells (RBCs) within the pulmonary capillaries. The RBC signal also exhibits cardiogenic oscillations that are reduced in precapillary pulmonary hypertension (PH). This effect is obscured in patients with concomitant defects in transfer from airspaces to RBCs, which increase RBC oscillation amplitudes. Here, we provide a framework for interpreting RBC oscillations and show their relationship to pulsatile blood flow, capillary blood volume, capillary compliance, and impedance of the capillary and venous circulation. This framework was first applied to characterize RBC oscillations in a cohort of subjects with pulmonary disease but no known PH (<i>n</i> = 129). ¹²⁹Xe MRI of RBC transfer was used to estimate capillary blood volume, and as it decreased, RBC oscillations sharply increased ([Formula: see text] = 0.53), consistent with model predictions. Model-derived fit parameters were then used to estimate the distribution of pulmonary vascular resistance (PVR) across arterial, capillary, and venous circulation and to correct oscillations for RBC transfer defects. Seventy percent of PVR was estimated to arise from pulmonary arteries, 11% from capillaries, and 19% from veins. When tested in a second cohort of subjects who underwent ¹²⁹Xe MRI/MRS and right heart catheterization (<i>n</i> = 40), oscillations corrected for capillary blood volume correlated moderately with PVR (<i>r</i>² = 0.27, <i>P</i> = 0.0014). For every 1.96 Wood units (WU) increase in PVR, corrected oscillations decreased by 1 absolute percentage point. This work demonstrates that, although ¹²⁹Xe-RBC oscillations are only indirectly sensitive to precapillary obstruction, corrected oscillations below 7.5% were 100% specific for elevated PVR.<b>NEW & NOTEWORTHY</b> Cardiogenic oscillations in the ¹²⁹Xe red blood cell (RBC) resonance decrease in precapillary pulmonary hypertension (PH) but are enhanced when capillary blood volume is reduced. To separate these effects, we developed a physiological model that used ¹²⁹Xe gas exchange MRI to estimate blood volume, which was used to correct oscillation amplitude measurements. Corrected amplitudes correlated significantly with pulmonary vascular resistance, highlighting the potential for future noninvasive detection of PH.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"623-633"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143052642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interactions of chronic stress exposure and stress appraisal on vascular endothelial function among young adults.","authors":"Alyssa S Carlson, Laura E Schwager, Thomas W Hart, Sara J Diesel, Jordan L Harris, Mark Flores, Kylee S West, Emily B K Thomas, Nathaniel D M Jenkins","doi":"10.1152/japplphysiol.00457.2024","DOIUrl":"10.1152/japplphysiol.00457.2024","url":null,"abstract":"<p><p>We investigated the associations of ongoing, chronic stress exposure and stress appraisal on vascular endothelial function (VEF) in young adults. In 72 healthy young adults (74% female; age = 25 ± 1 yr), we assessed chronic stress exposure and appraisal with a measure that quantified chronic stress exposure and chronic stress appraisal related to eight specific stressors over the last year. Participants completed the perceived stress scale (PSS) as a measure of global, proximal stress appraisal. VEF was assessed using the brachial artery flow-mediated dilation technique. We examined relations among ongoing, chronic stress exposure and stress appraisal versus VEF adjusted for age and sex, and then assessed whether stress appraisal moderated the effect of chronic stress exposure on VEF. Chronic stress exposure (β = -0.24, <i>P</i> = 0.045), but not chronic stress appraisal (β = 0.07, <i>P</i> = 0.56) or perceived stress (β = -0.20, <i>P</i> = 0.11), was related to VEF. Perceived stress (<i>P</i> = 0.046), but not chronic stress appraisal (<i>P</i> = 0.54), moderated the association between chronic stress exposure and VEF. The effect of chronic stress exposure on VEF ceased to be significant at a PSS score of ∼22. Subsequent exploratory stratified analysis indicated that those with PSS ≥22 had increased exposure to adverse childhood experiences (+1.6 ± 0.6, <i>P</i> = 0.01), greater depressive symptoms (+10.2 ± 2.7, <i>P</i> < 0.001), and reduced psychological resilience (-7.6 ± 3.5, <i>P</i> = 0.036). Chronic stress exposure significantly predicts impaired VEF among young adults. Furthermore, this relation is influenced by proximal perceived stress, such that the association of chronic stress exposure on VEF may be obscured at high levels of proximal perceived stress.<b>NEW & NOTEWORTHY</b> Our findings indicate that ongoing chronic stress exposure over the last year is significantly associated with reduced vascular endothelial function among apparently healthy young adults. Our data provide important insights into the interplay of chronic stress exposure versus proximal perceived stress and may also support the hypothesis that young adults who are sensitized to stress may be particularly vulnerable to stress-related impairments in vascular endothelial function.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"783-791"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142983522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}