Journal of applied physiology最新文献

{"title":"Oxidative stress suppresses internal carotid artery dilation to hypercapnia in healthy older adults.","authors":"Kaitlin A Freeberg, Narissa P McCarty, Michel Chonchol, Douglas R Seals, Daniel H Craighead","doi":"10.1152/japplphysiol.00322.2024","DOIUrl":"10.1152/japplphysiol.00322.2024","url":null,"abstract":"<p><p>Cerebrovascular disease and dementia risk increases with age, and lifetime risk is greater in women. Cerebrovascular dysfunction likely precedes cerebrovascular disease and dementia but the mechanisms are incompletely understood. We hypothesized that oxidative stress mediates cerebrovascular dysfunction with human aging. Internal carotid artery dilation (ICA_CO2 dilation) and middle cerebral artery cerebrovascular reactivity (MCA CVR_CO2) in response to hypercapnia (5% CO₂) were measured in 20 young [10 F/10 M; age 23 ± 3 yr (means ± SD)] and 21 older (11 F/10 M; age 69 ± 9 yr) adults during intravenous infusions of saline (control) and vitamin C (acutely reduced oxidative stress condition). ICA_CO2 dilation increased in response to vitamin C infusion in older adults (saline = 4.3 ± 2.4%; vitamin C = 6.7 ± 3.3%) but was unchanged in young adults (saline = 6.1 ± 2.7%; vitamin C = 5.5 ± 1.9%) (group × condition: <i>P</i> = 0.004). MCA CVR_CO2 was not different in response to vitamin C in either group (group × condition: <i>P</i> = 0.341). However, when separated by sex, older female participants exhibited increased MCA CVR_CO2 with vitamin C (saline = 0.85 ± 0.79 cm/s/mmHg; vitamin C = 1.33 ± 1.01 cm/s/mmHg) compared with older male participants (saline = 1.21 ± 0.57 cm/s/mmHg; vitamin C = 0.99 ± 0.47 cm/s/mmHg) (sex × condition: <i>P</i> = 0.011). Oxidative stress selectively impairs cerebrovascular function in older adults in an artery- and sex-specific manner.<b>NEW & NOTEWORTHY</b> This study is the first to report oxidative stress-mediated suppression of cerebrovascular reactivity to hypercapnia in the internal carotid artery in older compared with young adults. Overall, these in vivo findings identify oxidative stress as an important pathophysiological contributor to cerebrovascular aging in humans, highlighting the need to identify novel interventions that can reduce oxidative stress in the aging population.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"536-545"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143006014","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":"Running in the heat similarly reduces lipid oxidation and peak oxygen consumption in trained runners and inactive individuals.","authors":"Loïs Mougin, Heather Z Macrae, Alisha Henderson, Thomas G Cable, Lee Taylor, Lewis J James, Stephen A Mears","doi":"10.1152/japplphysiol.00710.2024","DOIUrl":"10.1152/japplphysiol.00710.2024","url":null,"abstract":"<p><p>This study compared oxygen consumption and substrate oxidation while exercising in hot and temperate conditions in individuals with different physical activity statuses (i.e., inactive individuals vs. trained runners). Ten inactive individuals (IA: 26 ± 6 yr; 79.1 ± 14.1 kg; 40.7 ± 5.1 mL·kg^-1·min^-1) and 10 trained runners (TR: 25 ± 6 yr; 69.5 ± 9.1 kg; 63.1 ± 5.1 mL·kg^-1·min^-1) completed two incremental exercise tests (4-min stages) until exhaustion in temperate (TEMP: 18.7 ± 0.1°C; 43.2 ± 4.1% relative humidity) and hot (HOT: 34.4 ± 0.2°C and 42.6 ± 1.6% relative humidity) conditions. Expired gas and blood lactate concentrations were measured at the end of each stage. Peak oxygen consumption similarly decreased in HOT compared with TEMP for IA and TR [-13.2 ± 4.5% vs. -15.2 ± 7%; <i>P</i> = 0.571; effect size (ES) = 0.25]. In HOT compared with TEMP, lipid oxidation, from 30% to 70% of peak oxygen consumption (V̇o_2peak), was reduced for both groups (IA: <i>P</i> = 0.023, ES = 0.43; TR: <i>P</i> < 0.001, ES = 0.72), whereas carbohydrate oxidation was increased for TR (<i>P</i> = 0.011; ES = 0.45) but not for IA (<i>P</i> = 0.268; ES = 0.21). Core temperature was different between conditions for TR (higher in HOT, <i>P</i> = 0.017; ES = 0.66) but not for IA (<i>P</i> = 0.901; ES = 0.25). Despite reduced physiological capacities in IA, both populations demonstrated reductions in lipid utilization and peak oxygen consumption in hot compared with temperate conditions. However, the increased carbohydrate oxidation in HOT for TR was not observed in IA, potentially explained by lower thermal strain. <b>NEW & NOTEWORTHY</b> This study shows that lipid oxidation and oxygen consumption are similarly affected by heat exposure in trained runners and inactive individuals. Carbohydrate oxidation and core temperature are greater in hot conditions in trained runners but not in inactive individuals. A lower metabolic heat production in inactive individuals for a similar relative intensity compared with trained runners could explain these differences in core temperature.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"508-517"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143039005","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":"Changes in H-reflex, V-wave, and contractile properties of the plantar flexors following concurrent exercise sessions-the acute interference effect.","authors":"Miguel Gomes, André D Gonçalves, Pedro Pezarat-Correia, Goncalo V Mendonca","doi":"10.1152/japplphysiol.00680.2024","DOIUrl":"10.1152/japplphysiol.00680.2024","url":null,"abstract":"<p><p>The interaction between muscle strength and endurance impacts athletic performance. Integrating both modalities into concurrent exercise (CE) is challenging due to the interference effect. This study explored the acute effects of resistance-only (R), endurance-only (E), and CE sessions on voluntary muscle strength, evoked neurophysiological parameters, and contractile properties of the plantar flexors. We also explored whether the sequence of CE (E-R vs. R-E) affects these parameters. Ten males (23.5 ± 2.4 yr) experienced in resistance and endurance training underwent neuromuscular baseline assessments, including plantarflexion maximal voluntary isometric contraction (MVIC) and soleus evoked responses (M-wave, H-wave, V-wave, evoked octet, and twitch contractile properties). Then, participants completed four different exercise sessions in a randomized manner (e.g., E, R, E-R, and R-E), separated by 72 h. Exercise sessions were immediately followed by the same assessments completed at baseline. MVIC and the rate of torque development (RTD) were reduced after all sessions. The E session induced a greater decrease in RTD compared with R. Although the V-wave amplitude decreased after all sessions, the electromyographic activity of the soleus muscle remained unchanged during MVIC. The normalized amplitude of the H-reflex was reduced after E and both CE sessions. The gain of the H-reflex ascending limb (H_slope) exhibited a larger decrease after CE, irrespectively of exercise sequence. The twitch contractile properties were similarly impaired after all sessions. The E session induced a larger reduction of the evoked octet response. These findings provide new insights into the neuromuscular etiology of the acute interference effect resulting from CE.<b>NEW & NOTEWORTHY</b> All exercise modalities reduced maximal isometric strength; however, endurance exercise led to greater decreases in the rate of torque development. Resistance exercise negatively impacted supraspinal central neural drive, whereas both endurance and concurrent exercise significantly impaired spinal motoneuron responsiveness. Endurance and concurrent exercise also significantly reduced twitch contractile properties and evoked octet responses, with the most pronounced impairments observed following endurance-only exercise.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"327-341"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142894689","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":"N₂ exchanges in hyperbaric environments: toward a model based on physiological gas transport (O₂ and CO₂).","authors":"Michael Theron, Alexis Blasselle, Lisa Nedellec, Pascal Ballet, Emmanuel Dugrenot, Bernard Gardette, François Guerrero, Anne Henckes, Jean-Pierre Pennec","doi":"10.1152/japplphysiol.00357.2024","DOIUrl":"10.1152/japplphysiol.00357.2024","url":null,"abstract":"<p><p>Decompression sickness can occur in divers even when recommended decompression procedures are followed. Furthermore, the physiological state of individuals can significantly affect bubbling variability. These informations highlight the need for personalized input to improve decompression in SCUBA diving. The main objective of this study is to propose a fundamental framework for a new approach to inert gas exchanges. A physiological model of oxygen delivery to organs and tissues has been built and adapted to nitrogen. The validation of the model was made by transferring the N₂ to CO₂. Under normobaric conditions (air breathing, oxygen breathing, and static apnea) and hyperbaric conditions, the O₂ model replicates the reference physiological Po₂ (Spearman correlation tests <i>P</i> < 0.001). The inert gas models can simulate inert gas partial pressures under normobaric and hyperbaric conditions. However, the lack of reference values prevents direct validation of this new model. Therefore, the N₂ model has been transferred to CO₂. The resulting CO₂ model has been validated by comparing it with physiological reference values (Spearman correlation tests <i>P</i> < 0.01). The validity of the CO₂ model constructed from the N₂ model demonstrates the plausibility of this physiological model of inert gas exchanges. In the context of personalized decompression procedures, the proposed model is of significant interest as it enables the integration of physiological and morphological parameters (blood and respiratory flows, alveolo-capillary diffusion, respiratory and blood volumes, oxygen consumption rate, fat mass, etc.) into a model of nitrogen saturation/desaturation, in which oxygen and CO₂ partial pressures can also be incorporated.<b>NEW & NOTEWORTHY</b> This is the first model of inert gas transport based on the physiology of respiratory gas. It was built for O₂ delivery and validated against literature data; it was then transposed to N₂ exchanges. The transposition procedure was checked by transposing the N₂ model to CO₂ (and validated against literature data). This model opens the possibility to integrate physiological and morphological inputs in a personalized decompression procedure in SCUBA diving.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"342-357"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142728893","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":"Ketone monoester ingestion improves cardiac function in adults with type 2 diabetes: a double-blind, placebo-controlled, randomized, crossover trial.","authors":"M Perissiou, Z L Saynor, K Feka, C Edwards, T J James, J Corbett, H Mayes, J Shute, M Cummings, M I Black, W D Strain, J P Little, A I Shepherd","doi":"10.1152/japplphysiol.00800.2024","DOIUrl":"10.1152/japplphysiol.00800.2024","url":null,"abstract":"<p><p>Type 2 diabetes (T2D) is a metabolic disease associated with cardiovascular dysfunction. The myocardium preferentially uses ketones over free fatty acids as a more energy-efficient substrate. The primary aim was to assess the effects of ketone monoester (K_me) ingestion on cardiac output index ([Formula: see text]i). The secondary aims were to assess the effects of K_me ingestion on markers of cardiac hemodynamics, muscle oxygenation, and vascular function at rest, during and following step-incremental cycling. We undertook a double-blind, randomized, crossover design study in 13 adults [age, 66 ± 10 yr; body mass index (BMI), 31.3 ± 7.0 kg·m^-2] with T2D. Participants completed two conditions, where they ingested a K_me (0.115 g·kg^-1) or a placebo taste-matched drink. Cardiac function was measured using thoracic impedance cardiography, and muscle oxygenation of the calf was determined via near-infrared spectroscopy. Macrovascular endothelial function was measured by flow-mediated dilation (FMD), and microvascular endothelial function was measured via transdermal delivery of acetylcholine (ACh) and insulin. Circulating β-hydroxybutyrate [β-Hb] was measured throughout. K_me ingestion raised circulating β-Hb throughout the protocol (peak 1.9 mM; <i>P</i> = 0.001 vs. placebo). K_me ingestion increased [Formula: see text]i by 0.75 ± 0.5 L·min^-1·m^-2 (<i>P</i> = 0.003), stroke volume index by 7.2 ± 4.5 mL·m^-2 (<i>P</i> = 0.001), and peripheral muscle oxygenation by 9.9 ± 7.1% (<i>P</i> = 0.001) and reduced systemic vascular resistance index by -420 ± -225 dyn·s^-1·cm^-5·m^-2 (<i>P</i> = 0.031) compared with the placebo condition. There were no differences between K_me and placebo in heart rate (<i>P</i> = 0.995), FMD (<i>P</i> = 0.542), ACh max (<i>P</i> = 0.800), and insulin max (<i>P</i> = 0.242). Ingestion of K_me improved [Formula: see text], stroke volume index, and peripheral muscle oxygenation but did not alter macro- or microvascular endothelial function in people with T2D.<b>NEW & NOTEWORTHY</b> For the first time, we show that acute ketone monoester ingestion (K_me) can increase cardiac output and stroke volume and reduce systemic vascular resistance at rest and during exercise in sodium glucose transporter inhibitors naïve (i.e. no drug-induced ketosis) people with type 2 diabetes. Acute K_me ingestion improves peripheral skeletal muscle oxygenation during moderate intensity and maximal exercise. K_me has no effect on macro- or microvascular endothelial function in people with type 2 diabetes.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"546-558"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143006006","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":"Dilatory responsiveness of the internal carotid artery to shear stimulus is constant under different levels of transient hypercapnia.","authors":"Rintaro Sakamoto, Tatsuki Kamoda, Shigehiko Ogoh, Kohei Sato, Masaki Katayose, Toru Neki, Erika Iwamoto","doi":"10.1152/japplphysiol.00774.2024","DOIUrl":"10.1152/japplphysiol.00774.2024","url":null,"abstract":"<p><p>Peripheral endothelial function, which accounts for the variability in shear stimulus, can be assessed using shear-mediated dilation normalized to the increased shear stimulus. Similarly, shear-mediated dilation of the internal carotid artery (ICA), an index of cerebrovascular endothelial function, should be normalized to increased shear stimulus. However, this approach has not yet been validated. Thus, the shear-mediated dilation of the ICA was assessed in 14 young adults during three levels of transient hypercapnia, induced by elevating the partial pressure of end-tidal carbon dioxide for 30 s by 6, 9, and 12 mmHg. The ICA shear rate (SR) was calculated using the ICA diameter and velocity, both measured by Doppler ultrasound. The total vasodilator stimulus was quantified as the SR area under the curve from the onset of hypercapnia to peak dilation, including and excluding baseline values [(SR_AUC) and delta SR_AUC (_DSR_AUC), respectively]. Shear-mediated dilation was calculated as the percent increase in diameter from baselines. ICA dilation was positively associated with _DSR_AUC [r_(rm) = 0.47, <i>P</i> < 0.01] but not with SR_AUC [r_(rm) = 0.32, <i>P</i> = 0.09]. Consequently, ICA dilation normalized to _DSR_AUC did not differ among trials (main effect of rial, <i>P</i> = 0.77). Contrarily, the difference in ICA dilation among trials remained significant when normalized to SR_AUC (main effect of trial, <i>P</i> = 0.02). Therefore, normalized shear-mediated dilation using _DSR_AUC can reduce variability associated with increased shear stimulus during ICA dilation assessment, thereby enhancing the validity of evaluating cerebrovascular endothelial function.<b>NEW & NOTEWORTHY</b> This study demonstrated that shear-mediated dilation of the internal carotid artery (ICA), an index of cerebrovascular endothelial function, increased with the increase of shear stimulus induced by different degrees of transient hypercapnia. However, when ICA dilation was normalized to the total increased shear stimulus above baseline, the vasodilation became comparable across different hypercapnia levels. Thus, normalizing ICA dilation to the total shear stimulus increased from baseline may enhance the validity of assessing cerebrovascular endothelial function.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"397-403"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142894704","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":"Cerebrovascular compliance during progressive hypotension in patients with autonomic failure.","authors":"Leena N Shoemaker, Aleena Sajid, Ronald Schondorf, J Kevin Shoemaker","doi":"10.1152/japplphysiol.00900.2024","DOIUrl":"10.1152/japplphysiol.00900.2024","url":null,"abstract":"<p><p>The compliant nature of cerebral blood vessels may represent an important mechanical protection for sustained cerebral perfusion during reductions in arterial blood pressure (ABP). However, whether the rise in cerebrovascular compliance (Ci) with falling ABP persists and exhibits a threshold effect remains unknown. Therefore, we analyzed Ci changes during graded head-up tilt (HUT) in individuals with autonomic failure (AF), a group that tolerates graded and progressive reductions in ABP. Finger ABP and middle cerebral artery blood velocity (MCAv) were recorded from five patients with AF (61 ± 22 yr) at supine rest and during graded HUT. Tilt gradients increased incrementally between 30, 45, and 60° every 5 min until ABP reached a critically low value. The total time in HUT was 11 ± 4 min. Every 5 s during supine and HUT, individual ABP and MCAv waveforms were assessed for Ci and cerebrovascular resistance (CVR) using a modified Windkessel model. Pulse pressure (PP) was calculated as systolic ABP - diastolic ABP. A threshold value for the increase in Ci was determined using breakpoint analysis of the linear relationship between changes in Ci and PP or ABP across tilt periods. Graded HUT resulted in reduced ABP, PP, CVR, and mean MCAv, and increased Ci (all <i>P</i> < 0.01). Ci began to increase progressively after PP fell by 22 ± 6 mmHg and ABP fell by 20 ± 11 mmHg. In conclusion, the increase in Ci during progressive hypotension exhibited a threshold effect and persisted as ABP continued to fall.<b>NEW & NOTEWORTHY</b> We identify a threshold effect for the increase in cerebrovascular compliance (Ci) during progressive hypotension (baseline vs. end-tilt: 86 ± 18 vs. 50 ± 8 mmHg) in individuals with autonomic failure, such that Ci began to increase progressively after pulse pressure fell by 22 ± 6 mmHg and arterial blood pressure fell by 20 ± 11 mmHg.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"468-472"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142983459","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":"Observing changes in motoneuron characteristics following distorted sensorimotor input via blood flow restriction.","authors":"Mansour Taleshi, Franziska Bubeck, Pascal Brunner, Leonardo Gizzi, Ivan Vujaklija","doi":"10.1152/japplphysiol.00603.2024","DOIUrl":"10.1152/japplphysiol.00603.2024","url":null,"abstract":"<p><p>Disruption of the blood supply to a limb in conjunction with active movement boosts muscle growth, aids in rehabilitation, and allows controlled exploration of the sensorimotor system. Yet, the underlying neuromechanical changes have not been observed in great detail. This study aims to report the acute neuromuscular effects of temporary blood flow restriction (BFR) through behavioral changes at the level of motor units (MUs) using high-density surface electromyography on the abductor digiti minimi muscle during 20 trapezoidal and sinusoidal isometric force tracking tasks (5 pre-BFR, 5 during BFR, and 10 post-BFR). Unsurprisingly, during BFR, reported discomfort levels increased significantly (ρ < 0.001) regardless of the task (+239% trapezoidal, +228% sinusoidal). However, BFR had very little impact on task tracking performance, though the reconstructed force derived from the underlying neural drive (smoothed cumulative spike train of MUs) deviated substantially during BFR (-40% in trapezoidal, -47% in sinusoidal). Regardless of the condition, the numbers of extracted MUs were consistent (20-26 in trapezoidal, 23-29 in sinusoidal). Interestingly, the interspike interval (ISI) of these units increased by 28% in trapezoidal and 24% in sinusoidal tasks during BFR, with ISI steadily returning to original values post-BFR. These results indicate that acute BFR transiently alters the active MU pool, and MU firing behavior, yet only slightly affects the resulting task performance. However, pre-BFR motor function is gradually restored after BFR release. These findings provide insights into the resulting effects of acute BFR administration and the complex response it elicits from the sensorimotor system.<b>NEW & NOTEWORTHY</b> To improve our understanding of how acute blood flow restriction (BFR) intervention affects neuromechanical function and motor unit characteristics, we applied high-density surface electromyography on the abductor digiti minimi muscle during isometric trapezoidal and sinusoidal precision force tracking tasks. Although BFR increased discomfort, it minimally affected force tracking performance; however, it did alter the underlying motor unit behavior. These findings further enhance our understanding of the neural mechanisms underlying BFR.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"559-570"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142983527","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":"Remote ischemic preconditioning attenuates ischemia-reperfusion injury-induced reductions in vascular function through release of endogenous opioids.","authors":"Alexander J Rosenberg, Alexander Fernandez, Ayrion W Moody, Justin D Sprick","doi":"10.1152/japplphysiol.00913.2024","DOIUrl":"10.1152/japplphysiol.00913.2024","url":null,"abstract":"<p><p>Remote ischemic preconditioning (RIPC) is a therapy characterized by repeated bouts of limb ischemia and reperfusion. RIPC protects against ischemia-reperfusion injury (IRI), and preclinical studies suggest that this is mediated through the release of endogenous opioids. We aimed to interrogate the role of endogenous opioids in RIPC-signaling in humans, using an arm model of IRI. We hypothesized that RIPC would attenuate IRI-induced reductions in brachial artery flow-mediated dilation (FMD) and that this would be prevented by systemic opioid receptor blockade. Eleven healthy adults (8 M/3 F, age = 28 ± 8 yr) completed three experimental visits in which IRI was induced via 20-min upper arm ischemia and 20-min reperfusion achieved via upper arm cuff inflation to 250 mmHg. FMD was measured at rest and again following IRI. During the control condition, RIPC was not performed. During the RIPC condition, RIPC was performed on the contralateral arm via four cycles of 5-min cuff inflation (250 mmHg) with 5-min reperfusion. During the opioid receptor blockade condition (naloxone), RIPC was performed in the presence of systemic opioid receptor blockade via intranasal naloxone (4 mg), which was administered during the first 5-min cycle of RIPC. The change in FMD from baseline versus post-IRI was compared between visits via a two-way repeated measures ANOVA (factor 1: time, factor 2: condition) followed by Tukey post hoc tests. IRI reduced FMD during the control (pre = 6.1 ± 2.4%, post = 3.5 ± 2.8%, <i>P</i> < 0.001) and naloxone (pre = 6.6 ± 2.7%, post = 3.5 ± 1.9%, <i>P</i> < 0.001) conditions but not during the RIPC condition (pre = 5.9 ± 2.2%, post = 4.9 ± 2.8%, <i>P</i> = 0.14). These findings demonstrate that RIPC provides vascular protection from IRI in humans through an opioid-dependent mechanism.<b>NEW & NOTEWORTHY</b> Remote ischemic preconditioning (RIPC) is a cardioprotective therapy characterized by brief cycles of limb ischemia and reperfusion. We demonstrate that a single bout of arm RIPC provides protection from ischemia-reperfusion injury-induced reductions in vascular function in healthy adults. This protection was attenuated when RIPC was administered in the presence of systemic opioid-receptor blockade via intranasal naloxone. These findings suggest that endogenous opioids contribute to RIPC-induced protection of vascular function in humans.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"571-576"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143006016","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":"Associations of cardiorespiratory fitness with cerebral cortical thickness and gray matter volume across the adult lifespan.","authors":"Junyeon Won, Tsubasa Tomoto, Takashi Tarumi, Karen M Rodrigue, Kristen M Kennedy, Denise C Park, Rong Zhang","doi":"10.1152/japplphysiol.00429.2024","DOIUrl":"10.1152/japplphysiol.00429.2024","url":null,"abstract":"<p><p>High cardiorespiratory fitness (CRF) is associated with reduced cortical thinning and gray matter (GM) shrinkage in older adults. We investigated associations of CRF measured with peak oxygen consumption (V̇o_2peak) with cortical thickness and GM volume across the adult lifespan. We hypothesized that higher CRF is associated with less cortical thinning and GM shrinkage across the adult lifespan, which is associated with better cognitive performance. This cross-sectional study recruited 172 sedentary yet healthy adults (65% women, 22-81 yr) who underwent treadmill exercise testing to measure V̇o_2peak, structural magnetic resonance imaging to assess cortical thickness and GM volume, and a comprehensive cognitive test battery to assess fluid cognitive function. Linear regression models were used to examine the associations of total and regional cortical thickness and GM volume with age, V̇o_2peak, and age × V̇o_2peak interaction after adjusting for sex, education, and total intracranial volume, and the associations of cortical thickness and GM volume with fluid cognitive performance. Mean and regional cortical thickness and total GM volume were associated negatively with age, whereas no associations were observed with V̇o_2peak. However, a significant interaction between age and V̇o_2peak on the right superior parietal volume indicated that aging was associated with smaller right superior parietal volume in the lower CRF group, whereas no association was observed in the higher CRF group. Larger right superior parietal volume was associated with better fluid cognitive performance. These findings highlight the importance of maintaining CRF to prevent or slow brain aging from an adult lifespan perspective.<b>NEW & NOTEWORTHY</b> High cardiorespiratory fitness may mitigate regional gray matter shrinkage across the adult lifespan.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"473-482"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143005998","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}