Journal of applied physiology最新文献

{"title":"Endoscopic sympathectomy impairs forearm cutaneous vascular conductance and sweating responses during passive whole body heat stress.","authors":"Rachel M Cottle, Scott L Davis, Dan M Meyer, Elizabeth A Gideon, Craig G Crandall","doi":"10.1152/japplphysiol.00583.2026","DOIUrl":"10.1152/japplphysiol.00583.2026","url":null,"abstract":"<p><p>Hyperhidrosis is characterized by excessive sweating, typically in the palmar and axillary regions. Individuals with severe cases of hyperhidrosis can be treated surgically via endoscopic thoracic sympathectomy to disrupt the neural connection between the spinal cord and the affected regions, thereby attenuating sweating in the hyperhidrotic regions. However, the effects of this procedure on skin blood flow and sweating responses to whole body heat stress in regions not targeted by the sympathectomy, such as the forearm, are unknown. We tested the hypothesis that surgical sympathectomy attenuates the increase in forearm cutaneous vascular conductance and sweating during whole body heat stress. Before and 7 ± 1 wk following bilateral thoracic surgical sympathectomy, forearm skin blood flow (laser-Doppler imaging) and local sweat rate (capacitance hygrometry) were assessed during whole body passive heat stress sufficient to elevate core temperature by ∼1°C (<i>P</i> = 0.74 between trials) in 10 subjects (27 ± 3 yr; 7 females). The mean increase in forearm cutaneous vascular conductance was attenuated following sympathectomy (Δ3.67 ± 1.34 flux·mmHg^-1 vs. Δ1.62 ± 1.19 flux·mmHg^-1; <i>P</i> < 0.01). Similarly, mean sweat rate was attenuated in the palmar (Δ0.68 ± 0.42 mg·min^-1·cm^-2 vs. Δ0.20 ± 0.25 mg·min^-1·cm^-2; <i>P</i> = 0.015) and forearm (Δ0.62 ± 0.31 mg·min^-1·cm^- vs. Δ0.24 ± 0.26 mg·min^-1·cm^-2; <i>P</i> = 0.03) regions following sympathectomy. These data suggest that the increase in forearm cutaneous vascular conductance and sweat rate in response to whole body heat stress is attenuated by ∼50% after surgical sympathectomy. However, the implications of these responses on whole body thermoregulation remain unknown.<b>NEW & NOTEWORTHY</b> Thoracic surgical sympathectomy is often performed to attenuate sweating in the palmar and axillary regions in individuals with hyperhidrosis. However, the effect of this procedure on efferent thermoregulatory responses to heat stress is unknown. We show that the increase in forearm cutaneous vascular conductance and local sweat rate is attenuated during whole body passive heating following a surgical sympathectomy.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1040-1044"},"PeriodicalIF":3.7,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13622889/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148930075","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":"Staying in the saddle: a case study of an elite cyclist during pregnancy.","authors":"Paris A T Jones, Joscelin Lowden, Jelle de Jong, Len Parker Simpson, Margie H Davenport","doi":"10.1152/japplphysiol.00110.2026","DOIUrl":"10.1152/japplphysiol.00110.2026","url":null,"abstract":"<p><p>There is a distinct lack of understanding regarding the training patterns of elite athletes during pregnancy. This retrospective case study of training data is the first to our knowledge to examine the training patterns, performance, health, and delivery outcomes of a 35-yr-old professional cyclist across the perinatal period. During her pregnancy, she cycled a total of 351.15 h (approximately four times the current minimum recommendations) with an average of 9.00 ± 5.42 h/wk with no health complications or injuries. She trained regularly (4 ± 2 sessions/wk) at moderate to vigorous intensity for the majority (95%) of the training sessions during her pregnancy. The average altitude that the participant cycled at during pregnancy was 564.83 ± 587.52 m with a maximum altitude of 2,310 m and a maximum solar load of 46°C. She delivered via planned cesarean section at 38+5 week of gestation and experienced no maternal or fetal complications.<b>NEW & NOTEWORTHY</b> This case study provides one of the first descriptions of a pregnant female cyclist's training patterns, performance, health, and delivery outcomes across one pregnancy.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1032-1039"},"PeriodicalIF":3.7,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148880169","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":"Exploring the placental lipidome in physically active versus inactive pregnancies.","authors":"Meaghan L MacDonald, Anahita Yadegari, Justine T Chittaro, Arthur Dantas, Karl Wasslen, Christian A Rosales, Jane Shearer, Leanne M Redman, Jeff Smith, Kristi B Adamo","doi":"10.1152/japplphysiol.00357.2026","DOIUrl":"10.1152/japplphysiol.00357.2026","url":null,"abstract":"<p><p>Physical activity during pregnancy is highly beneficial, but the mechanisms underlying these benefits have not been elucidated. Given its central role in supporting pregnancy, the placenta is a primary target for investigation. We implemented untargeted lipidomic analysis on 36 human placenta samples collected at term from uncomplicated pregnancies. Participant activity levels were objectively measured using accelerometry, and participants were categorized as physically active or inactive. Samples were assessed by liquid chromatography-tandem mass spectrometry. The docosahexaenoic acid (DHA) transporter major facilitator superfamily domain-containing 2a (MFSD2a) was analyzed with Western blot. A total of 192 lipids were annotated. Among these, 34 lipid species differed significantly between groups [|log2FC| ≥ 0.58; false discovery rate (FDR)-adjusted <i>P</i> < 0.05]. Multivariate analyses demonstrated modest separation between groups. DHA was identified in 17 lipid species, and seven were higher in the active group. Area under the receiver operating characteristic curve revealed five lipids with perfect group separation. Pathway analysis showed enrichment of the phosphatidylserine decarboxylase pathway in the active group. No differences in MFSD2a expression were identified. The results demonstrate a relationship between physical activity and the placental lipidome. Several DHA species are higher in the active group, suggesting improved fetal availability for brain and retinal development. Lipids with perfect group separation may represent biomarkers of physical activity. Multiple lipid species and pathways warranting future targeted investigation are highlighted.<b>NEW & NOTEWORTHY</b> This paper provides novel insight into the placental lipidome in relation to physical activity status in uncomplicated pregnancies. Lipid profiles differ significantly between physically active and inactive groups. Several lipids containing DHA, an essential omega-3 fatty acid with critical roles in fetal brain development, were found to be higher in placentas from active pregnancies. Thirty-four differentially expressed lipids were identified, highlighting future avenues for exploring how physical activity impacts pregnancy outcomes.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1057-1068"},"PeriodicalIF":3.7,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148968325","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":"Effects of coronary sinus reducer on oxygen transport in myocardial ischemia.","authors":"Mythri Tumbalam Gooty, Haifeng Wang, Jenny S Choy, Sujal Laxmikant Vajire, Ghassan S Kassab, Lik-Chuan Lee","doi":"10.1152/japplphysiol.90262.2026","DOIUrl":"https://doi.org/10.1152/japplphysiol.90262.2026","url":null,"abstract":"<p><p>Although the coronary sinus reducer (CSR) has emerged as a promising therapeutic intervention for patients with refractory angina, its underlying mechanistic basis remains incompletely understood. Specifically, how CSR affects microvascular hemodynamics, and O₂ transport under ischemic conditions, has not been established. To address this issue, we developed a multiscale computational framework that couples closed-loop coronary hemodynamics with an advection-diffusion model of O₂ transport to evaluate the effects of CSR across varying degrees of myocardial ischemia. Simulations show that CSO elevates coronary sinus (CS) pressure, increases venous-capillary pressure gradients, and induces retrograde venous flow that helps redistribute blood from non-ischemic territories to ischemic territory. This retrograde flow increases mean pO₂ in the ischemic capillary bed by 47% (3.14 ± 6.05 mmHg in severe ischemia to 4.63 ± 5.54 mmHg with CSO) and reduced the fraction of severely hypoxic capillaries from 76% to 58%, providing a partial alternative pathway for O₂ delivery when arterial inflow to capillaries is critically reduced. These results provide a quantitative mechanistic explanation for the clinical improvements observed with CSR therapy for patients who are not candidates for revascularization. Finally, this model highlights the impact of severity of arterial stenosis and microvascular O₂ transport on the therapeutic efficacy of the CSR.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149109472","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":"The effect of infrared radiation-emitting garments on the acute skeletal muscle molecular signalling responses to high-intensity interval exercise.","authors":"Jack W Bond, Patrick T Harrison, Hannah F Dugdale, Neil R W Martin, Stephen J Bailey, Tim Brownstone, Richard A Ferguson","doi":"10.1152/japplphysiol.00258.2026","DOIUrl":"10.1152/japplphysiol.00258.2026","url":null,"abstract":"<p><p>Infrared radiation (IR) has previously been demonstrated to activate signalling pathways involved in mitochondrial biogenesis and angiogenesis. We tested the hypothesis that IR-emitting fabric (IREF) would enhance translocation and phosphorylation of proteins, and mRNA expression of genes, associated with mitochondrial biogenesis and angiogenesis in response to high-intensity interval exercise (HIIE) compared with non-IREF. Eleven males (age, 22 ± 4 yr, [Formula: see text], 48.0 ± 4.6 mL·kg^-1·min^-1) completed two HIIE sessions consisting of 10 × 3 min intervals at a power output equivalent to 60% of the difference between gas exchange threshold and peak power output. Each interval was interspersed with 3 min at 25 W. In a repeated-measures, counterbalanced, single-blind design, participants wore IREF and non-IREF clothing (SHAM) before, during, and following HIIE. Muscle biopsies were obtained pre (Baseline), immediately post (PE), and 3 h post exercise (3hPE). Cytosolic and nuclear <i>p</i>-calmodulin (CaM)-dependent kinase II (CaMKII) content were both greater at PE in IREF compared with SHAM (<i>P</i> = 0.001 and <i>P</i> = 0.003, respectively). Cytosolic and nuclear <i>p</i>-p38 mitogen-activated protein kinase content increased from baseline to PE in IREF (<i>P</i> = 0.008 and <i>P</i> = 0.005, respectively) but not in SHAM. Nuclear respiratory factor 1 (<i>NRF1)</i> and <i>TP53</i> mRNA expression were greater in IREF compared with SHAM PE (<i>P</i> ≤ 0.013) and 3hPE in <i>NRF1</i> only (<i>P</i> = 0.002). There was no change in the phosphorylated protein content or gene expression of any angiogenesis-related target in IREF compared with SHAM. Wearing IREF before, during, and following HIIE augments some of the acute cellular signalling cascades associated with mitochondrial biogenesis.<b>NEW & NOTEWORTHY</b> Infrared radiation (IR) has been demonstrated to activate skeletal muscle cellular signalling pathways. We show that wearing IR-emitting fabric (IREF) before, during, and following high-intensity interval exercise (HIIE) augmented some of the acute cellular signalling cascades associated with mitochondrial biogenesis. Specifically, IREF enhanced the phosphorylation of CaMKII and the mRNA expression of <i>NRF1</i> and <i>TP53</i> compared with a non-IREF sham condition. Whether these acute changes translate to enhanced chronic adaptation remains to be determined.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1194-1207"},"PeriodicalIF":3.7,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149061150","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":"Total energy expenditure and water turnover during a 322 km mountain ultramarathon.","authors":"Alejandro M Rosales, Dustin R Slivka, Dale A Schoeller, Timothy C Shriver, Michele N Ravelli, Brent C Ruby","doi":"10.1152/japplphysiol.00677.2026","DOIUrl":"10.1152/japplphysiol.00677.2026","url":null,"abstract":"<p><p>High doubly labeled water (DLW) derived total energy expenditure (TEE) and water turnover (rH₂O) occur during 161 km (100-mile) ultramarathons. TEE and rH₂O during races exceeding 161 km and requiring multiple days to complete constitute an anomalous physiological stressor to further elucidate duration-dependent limits of human endurance. To quantify TEE and rH₂O during a multiday mountain ultramarathon, two runners [female (R1) and male (R2)] completed 322 km following DLW (²H₂¹⁸O) consumption. TEE and rH₂O were calculated from urinary isotopic elimination rates. Race-provided GPS monitors measured duration, moving time, and nonactivity time. R1 finished in 73.6 h at a pace of 1.3 m·s^-1 with nonactivity/rest time totaling 32% of the race (50.3 h moving and 23.3 h resting). In-race TEE for R1 was 123.9 MJ (29,376 kcals) and 35.5 MJ·day^-1 [8,408 kcals·day^-1, 5.6 times the basal metabolic rate (×BMR)] when expressed per 24 h. In-race rH₂O for R1 was 35.2 L (10.1 L·day^-1). R2 finished in 89.9 h at a pace of 1.0 m·s^-1 with nonactivity/rest time totaling 52% of the race (43.0 h moving and 46.9 h resting). In-race TEE for R2 was 164.2 MJ (38,909 kcals) and 41.1 MJ·day^-1 (9,737 kcals·day^-1, 5.0 × BMR) when expressed per 24 h. In-race rH₂O for R2 was 47.5 L (11.9 L·day^-1). Akin to 161 km events, multiday events are exceptional human endurance feats, demonstrating large absolute TEE and rH₂O values. However, the daily TEE range of multiday events appears diluted by unique nonactivity time needs (rest, sleep). Thus, the human endurance metabolic ceiling will be largely contingent upon event duration.<b>NEW & NOTEWORTHY</b> Multiday ultra-endurance events are exceptional human endurance feats as evidenced by large absolute total energy expenditure and water turnover values. Previously reported curvilinear constraints of metabolic activity during multiday ultra-events may be a function of the accrued nonactivity time, as total energy expenditure rate may fluctuate between periods of ambulation and nonambulation. Thus, the human endurance metabolic ceiling will be largely contingent upon event duration.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1129-1134"},"PeriodicalIF":3.7,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149038758","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":"Correction for Kistemaker et al., volume 134, 2023, p. 980-991.","authors":"","doi":"10.1152/japplphysiol.00733.2021_COR2","DOIUrl":"https://doi.org/10.1152/japplphysiol.00733.2021_COR2","url":null,"abstract":"","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":"141 4","pages":"1098"},"PeriodicalIF":3.7,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149074951","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":"Sagittal and frontal interplane balance control variability is minimized at preferred walking speed in healthy young adults.","authors":"Hsuan-Lun Lu, Cheng-Hao Yu, Tung-Wu Lu","doi":"10.1152/japplphysiol.00258.2025","DOIUrl":"10.1152/japplphysiol.00258.2025","url":null,"abstract":"<p><p>Reduced preferred walking speed (PWS) is a known indicator of increased fall risk, particularly sideways falls in individuals with reduced physical capacity, often attributed to decreased mediolateral stability in the frontal plane. The underlying mechanisms and the impact of walking speed on interplane balance control coordination remain unclear. The current study aimed to develop a novel analytical framework for quantifying the sagittal and frontal interplane coordination of center of mass (COM)-center of pressure (COP) control and its variabilities during level walking via continuous relative phase (CRP) angles and to study the walking speed effects. Fifteen young adults walked at PWS, slower and faster, whereas the COM-COP inclination angles (IAs) and their rates of change (RCIA) were measured to calculate interplane CRP patterns. The deviation phases (DP) of CRP curves quantified the variability of interplane coordination. The interplane balance control coordination and variability were significantly influenced by walking speed, with minimum DP values occurring during double limb support at PWS. Walking at one's PWS represents the best compromise for minimizing control variability between the sagittal and frontal planes. This novel approach highlights the role of interplane balance control variability in determining PWS in young adults and emphasizes the importance of monitoring these variables for fall risk assessment.<b>NEW & NOTEWORTHY</b> The current study described a novel approach based on continuous relative phase analysis to quantify the interplane coordination of balance control during gait in young adults. This approach highlights the role of interplane balance control variability in determining preferred walking speed in young adults and emphasizes the importance of monitoring these variables for fall risk assessment in diverse populations.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1106-1115"},"PeriodicalIF":3.7,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148944942","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":"β-Adrenergic receptors do not impact exercise hyperemia during rhythmic handgrip exercise in males and females.","authors":"Connor J Doherty, Trevor James King, Benjamin P Thompson, Jou-Chung Chang, Leah M Mann, Armando Aguero, Kacper Wojcik, Ira Carson, Jason S Au, Glen E Foster, Paolo B Dominelli","doi":"10.1152/japplphysiol.00497.2026","DOIUrl":"10.1152/japplphysiol.00497.2026","url":null,"abstract":"<p><p>Sex differences in exercise hyperemia remain unclear, and the role of β-adrenergic receptors (β-AR) in this response is unknown. Accordingly, we examined the role of β-AR in modulating central and peripheral hemodynamic responses to rhythmic handgrip exercise in 10 females and 7 males under control conditions (CON) and during β-AR blockade with oral propranolol (PROP). Participants completed a low-intensity (10% maximal voluntary contraction) and incremental (40, 80, and 120 N) rhythmic handgrip exercise. Hemodynamic variables, including heart rate (HR), mean arterial pressure (MAP), brachial artery diameter (BA_D), forearm blood flow (Q̇_ARM), and vascular conductance (VC_ARM), were assessed at baseline and during steady-state exercise for each intensity. The overall hyperemia response was assessed as the slope of the relationship between Q̇_ARM and VC_ARM over exercise intensity. β-AR blockade was achieved with two 80 mg doses of oral HCl propranolol administered 7.5 and 1.5 h before the PROP visit. β-adrenergic blockade reduced HR and absolute Q̇_ARM in males and females (both, <i>P</i> < 0.05), but not MAP (<i>P</i> = 0.49). The overall exercise hyperemia slope response for Q̇_ARM and VC_ARM did not differ by sex or with β-AR blockade (both <i>P</i> > 0.05), even after adjusting to maximal handgrip strength (both, <i>P</i> > 0.05). The relative increase in BA_D from baseline was blunted in females (<i>P</i> = 0.03) but not males (<i>P</i> = 0.96) during PROP. In conclusion, the exercise hyperemia response is preserved in males and females with systemic β-adrenergic receptor blockade. However, young females appear to have a greater reliance on β-AR relative to males in mediating macrovascular tone during exercise.<b>NEW & NOTEWORTHY</b> β-adrenergic blockade reduced heart rate without affecting blood pressure in either sex. Exercise hyperemia did not differ between sexes and was unchanged with β-adrenergic blockade, even after normalizing for interindividual variability in resting blood flow and participant strength. Brachial artery dilation relative to baseline was blunted in females with propranolol, suggesting a sex-specific β-adrenergic mechanism mediating vascular control, whereas overall hyperemia was not impacted.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1171-1183"},"PeriodicalIF":3.7,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149030483","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":"A controlled comparison of two different calfactant preparations in a surfactant-deficient lamb model.","authors":"George P Albert, Daniel Swartz, Corey Commaroto, James J Cummings","doi":"10.1152/japplphysiol.00344.2026","DOIUrl":"10.1152/japplphysiol.00344.2026","url":null,"abstract":"<p><p>Calfactant is an animal-derived surfactant, FDA-approved for endotracheal tube administration. Complications during surfactant administration may be related to the volume being delivered. We conducted a controlled comparison of calfactant against a more concentrated, lower-volume calfactant. We compared the efficacy and complications of delivery of the two calfactant formulations to each other, and to no surfactant treatment, in the well-established preterm newborn lamb model of surfactant-deficient respiratory distress syndrome. After initial stabilization, a single dose of liquid calfactant or sham air instillation was given, and animals were maintained on mechanical ventilation for up to 6 h. Reflux of surfactant into the endotracheal airway occurred in 83% of calfactant-treated lambs versus 33% of more concentrated, lower-volume calfactant-treated lambs. Lambs treated with a more concentrated, lower-volume calfactant required less positive-pressure breaths to clear refluxed surfactant (4 ± 2 vs. 30 ± 8) and less time to deliver surfactant (70 ± 10 vs. 130 ± 29 s). Ventilation and oxygenation improved significantly in surfactant-treated lambs, but not in controls. Four of six control lambs met adverse endpoint criteria before 6 h, whereas all surfactant-treated lambs remained stable up to 6 h. We conclude that a more concentrated, lower-volume calfactant has similar efficacy to calfactant but can be delivered more quickly and with less risk of complications.<b>NEW & NOTEWORTHY</b> In a preterm animal model of surfactant-deficient respiratory distress, we compared a concentrated, lower-volume calfactant to its commercial counterpart. The lower-volume calfactant could be administered in a single aliquot, was associated with less surfactant reflux, required less positive-pressure breaths to clear reflux, and had a shorter administration time. A more concentrated surfactant may offer a more favorable administration risk/benefit profile for surfactant replacement therapy, minimizing surfactant delivery-associated stress.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1184-1193"},"PeriodicalIF":3.7,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149061445","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}