Physiological Reports最新文献

Alterations in the gut microbiome have been linked to obesity, with maternal high-fat diet (HF) playing a role in shaping offspring microbiome composition. However, the sex-specific responses to maternal HF diet and the impact of subsequent dietary challenges remain unclear. This study investigated the effects of maternal HF diet on offspring gut microbiota structure and predicted functional profile in response to short-term postnatal HF diet exposure with a focus on sex-specific responses. Female and male offspring of maternal control (C) diet or maternal HF diet were weaned onto C diet or HF diet. Offspring were euthanized at 13 weeks of age and cecal contents were collected for bacterial taxonomic profiling. Maternal HF diet reduced α-diversity, notably in male offspring weaned onto HF diet. Sex-specific differences were observed in the gut microbial composition and predicted functional potential. Furthermore, the influence of maternal diet on bacterial community structure and functional potential varied depending on postnatal diet. Maternal HF diet led to increased relative abundance of Corynebacterium in female offspring and decreased abundance of Akkermansia and Roseburia in male offspring. These findings underscore the sexually dimorphic nature of maternal HF diet effects on gut microbiota composition and function, with implications for developmental programming and metabolic health.

It is important to understand the effects of environmental factors such as air pollution on mitochondrial structure and function, especially when these changes increase cardiovascular disease risk. Although lifestyle choices directly determine many mitochondrial diseases, increasingly, it is becoming clear that the structure and function of mitochondria may be affected by pollutants found in the atmosphere (e.g., gases, pesticides herbicide aerosols, or microparticles). To date, the role of such agents on mitochondria and the potential impact on cardiovascular fitness is neglected. Here we offer a review of airborne stressors and pollutants, that may contribute to impairments in mitochondrial function and structure to cause heart disease.

Intraflagellar transport protein 88 (Ift88) is required for the formation of cilia in the thymus and non-ciliary dependent functions including T cell immune synapse formation. To test the role of Ift88 in T cell development, we performed flow cytometry analysis on thymus and spleen tissue isolated from mice lacking Ift88 in thymic epithelial cells (TECs) or T cells. Analyses indicated that TEC Ift88 deletion had no impact on thymic T cell development and minimal impact on splenic T cells. Analysis of T cells in CaggCre^ERT2+Ift88 ^tm1BkymTmG mice indicate that approximately half of DN1 thymocytes are Ift88 deficient 3 weeks post-tamoxifen induction; Ift88 loss did not impact T cell development at the DN2-DN4 stage or the CD4+/CD8+ double-positive (DP) thymocyte stage. However, survival of Ift88 deficient T cells was significantly reduced at the single-positive (SP) thymocyte stage, as was the number of CD4+ and CD8+ T cells in spleen and kidney. Despite preferential survival of Ift88-proficient cells, the total number of T cells the in spleen and kidney was minimally impacted by Ift88 loss. These data suggest Ift88 is required for differentiation of DP thymocytes into SP thymocytes and that Ift88 proficient T cells can compensate for deficient cells to fill the open niche.

This pilot study sought to explore the contribution of the large intestine microbiota to energy metabolism and exercise performance through its ability to degrade fibers into short-chain fatty acids (SCFAs). To investigate this, a correlational study was carried out on athlete horses under the same management conditions. Fecal microbiota diversity and composition, fibrolytic efficiency and SCFAs were analyzed. An incremental running test was carried out to estimate the maximal running speed (MRS) of the horses, and blood samples were taken to measure energy metabolism parameters. MRS was positively correlated with the efficiency of the fecal microbiota in degrading cellulose in vitro (r = 0.51; p = 0.02). The abundance of fibrolytic bacterial taxa was not associated with MRS, but functional inference analysis revealed a positive association between MRS and pathways potentially related to fibrolytic activity (r = 0.54; p = 0.07 and r = 0.56; p = 0.05 for butyrate metabolism and thiamine metabolism, respectively). In contrast, the metabolic pathway of starch degradation appeared negatively associated with MRS (r = -0.55; p = 0.06). The present findings suggest a potential contribution of the large intestine microbiota and dietary fibers digestion to exercise capacity in equine athletes.

Partaking in regular exercise has vast psychological and physiological benefits. However, factors that promote sedentary lifestyle such as occupational obligations (desk-based work) or underlying health comorbidities can limit adherence to exercise regimes. Considering the current trends in physical inactivity, development of alternate strategies to replicate or mimic the beneficial adaptations associated with regular exercise may become a highly sought after commodity. A relevant and current example of this is the enormous market demand for glucagon-like peptide-1 drugs for the management of obesity and type-2 diabetes. The goal of this short review is to direct attention toward non-pharmaceutical strategies and specifically focuses on the topical application of heat stress to passively improve health. The review highlights important heat-induced adaptations and identifies scope for technological innovations that will allow delivery of heating interventions outside the confinement of laboratory settings.

Liver fibrosis is an exaggerated wound healing response defined by the excessive accumulation of extracellular matrix. This study investigated the antifibrotic potential of naringenin (NRG), asiatic acid (AA), and icariin (ICA) using murine and human precision-cut liver slices (PCLS). These natural products have shown promise in animal models, but human data are lacking. In this study, PCLS prepared from male mouse liver tissue (mPCLS), healthy human liver tissue (hhPCLS), and cirrhotic human liver tissue (chPCLS) were cultured for 48 h with varying concentrations of the three compounds. Our findings indicate that NRG reduced collagen type 1 (COL1A1) expression in a concentration-dependent manner in both mPCLS and chPCLS, decreased fibrosis-related gene expression, and significantly lowered pro-collagen type 1 (PCOL1A1) levels in the culture medium by 54 ± 21% (mPCLS) and 78 ± 35% (chPCLS). Furthermore, NRG effectively inhibited IL-1β and TNF-α in mPCLS and IL-1β in chPCLS on both gene and protein levels. AA specifically reduced COL1A1 and PCOL1A1 in chPCLS, while ICA selectively downregulated Col1a1 and Acta2 gene expression in mPCLS. This study suggests NRG's potential as an effective antifibrotic agent, warranting further investigation into its mechanisms and therapeutic applications in liver fibrosis.

We evaluated associations between muscle phenotype, positional role, and on-ice performance in male U20 Danish national team ice hockey players. Sixteen players (10 forwards, six defensemen) participated in a game with activity tracking. Resting thigh muscle biopsies were analyzed for metabolic enzyme activity and protein expression linked to performance. On-ice intermittent exercise capacity, repeated sprint ability, and maximal isometric knee-extensor torque were also assessed. No significant position-specific muscle phenotype characteristics were found, but forwards generally exhibited higher levels of several membrane proteins (p = 0.100-0.991). NAKα₂, NAK∑, K_ATP, ClC-1, and NHE1 showed significant correlations with total distance (r = 0.52-0.59, p = 0.016-0.046), however, within positions these only persisted for K_ATP (r = 0.70, p = 0.024) and NAKα₂ (r = 0.57, p = 0.085) in forwards, where CS enzyme activity also displayed a strong association with distance covered (r = 0.75, p = 0.019). For high-intensity skating, NAKα₂ (r = 0.56, p = 0.025) and K_ATP (r = 0.50, p = 0.048) similarly exhibited the strongest associations, persisting within forwards (r = 0.63, p = 0.052 and r = 0.72; p = 0.018, respectively). In conclusion, although several muscle proteins involved in ion and metabolic regulation were associated with performance, only NAKα₂ and K_ATP displayed consistent relationships within positions. Moreover, CS enzyme activity was strongly related to total distance within forwards, coherent with the proposed importance of oxidative capacity in intense intermittent exercise.

Information is scarce on human responses to high pressure exposures out of water, such as related to tunnel construction workers. We hypothesized that differences in the longer durations of exposures for tunnel workers versus underwater divers results in greater inflammatory responses linked to the pathophysiology of decompression sickness (DCS). Blood was analyzed from 15 tunnel workers (36.1 ± 10.5 (SD) years old, 6 women) exposed to 142-156 kPa pressure for 4.1-4.9 h compared to 8 SCUBA divers (39.3 ± 13.3 (SD) years old, 6 women) exposed to 149 kPa for 0.61 hours. Despite differences in pressure duration between groups, elevations were the same for blood microparticles (MPs) (128 ± 28% MPs/μl) and intra-MPs interleukin (IL-1β) (376 ± 212% pg/million MPs), and for decreases of plasma gelsolin (pGSN, 31 ± 27% μg/mL). The number of circulating CD66b + neutrophils and evidence of cell activation, insignificant for divers, increased in tunnel workers. Across 3 exposures, the mean neutrophil count increased 150 ± 11%. Neutrophil activation increased by 1 to 2% of cells expressing cell surface CD18, myeloperoxidase, platelet-specific CD41, and decrease of cell bound pGSN. We conclude that MPs elevations occur rapidly in humans and reach steady state in minutes with pressure exposures and neutrophil activation requires significantly longer exposure times.

We sought to determine the repeatability of EFL in healthy adults during incremental cycle exercise. We hypothesized that the repeatability of EFL would be "strong" when assessed as a binary variable (i.e., absent or present) but "poor" when assessed as a continuous variable (i.e., % tidal volume overlap). Thirty-two healthy adults performed spirometry and an incremental cycle exercise test to exhaustion on two occasions. Standard cardiorespiratory variables were measured at rest and throughout exercise, and EFL was assessed by overlaying tidal expiratory flow-volume and maximal expiratory flow-volume curves. The repeatability of EFL was determined using Cohen's κ for binary assessments of EFL and intraclass correlation (ICC) for continuous measures of EFL. During exercise, n = 12 participants (38%) experienced EFL. At peak exercise, the repeatability of EFL was "minimal" (κ = 0.337, p = 0.145) when assessed as a binary variable and "poor" when measured as a continuous variable (ICC = 0.338, p = 0.025). At matched levels of minute ventilation during high-intensity exercise (i.e., >75% of peak oxygen uptake), the repeatability of EFL was "weak" when measured as a binary variable (κ = 0.474, p = 0.001) and "moderate" when measured as a continuous variable (ICC = 0.603, p < 0.001). Our results highlight the day-to-day variability associated with assessing EFL during exercise in healthy adults.

The age-related loss of muscle mass is partly accounted for by the loss of sarcomeres in series, contributing to declines in muscle mechanical performance. Resistance training biased to eccentric contractions increases serial sarcomere number (SSN) in young muscle, however, maximal eccentric training in old rats previously did not alter SSN and worsened performance. A submaximal eccentric training stimulus may be more conducive to adaptation for aged muscle. The purpose of this study was to assess whether submaximal eccentric training can increase SSN and improve mechanical function in old rats. Twelve 32-month-old male F344/BN rats completed 4 weeks of submaximal (60% maximum) eccentric plantar-flexion training 3 days/week. Pre- and post-training, we assessed in-vivo maximum isometric torque at a stretched and neutral ankle angle, the passive torque-angle relationship, and the isotonic torque-velocity-power relationship. The soleus and medial gastrocnemius (MG) were harvested for SSN measurements via laser diffraction, with the untrained leg as a control. SSN increased 11% and 8% in the soleus and MG, respectively. Training also shifted optimal torque production towards longer muscle lengths, reduced passive torque 42%, and increased peak isotonic power 23%. Submaximal eccentric training was beneficial for aged muscle adaptations, increasing SSN, reducing muscle passive tension, and improving dynamic contractile performance.