Frontiers in Physiology最新文献

Introduction: The heavy metal elements cadmium (Cd) and zinc (Zn) often coexist in nature, making the environmental media more prone to compound pollution. However, research on the toxic effect of the Cd-Zn combination is still lacking, and the underlying toxic mechanisms remain unclear.

Methods: Therefore, in this experiment, we established four treatment groups with different ratios of Cd-Zn compound stress for the broad bean, Vicia faba L., and aphids, Megoura crassicauda, to explore the growth and physiological adaptation mechanisms under different levels of mixed heavy metal stress.

Results: By measuring the germination rate, seedling height, and chlorophyll content of broad beans, we found that Cd-Zn-mixed stress has a synergistic inhibitory effect on the growth and development of broad beans. Cd and Zn can be transferred through the food chain, while broad beans can resist complex stress by regulating the content of total soluble sugars and photosynthetic pigments in the body, as well as accumulating proline. In addition, in the first generation of adult aphids, treatment with Cd (12.5 mg/kg) + Zn (100 mg/kg) significantly affected the expression of trehalase (TRE) and trehalose-6-phosphate synthase (TPS) genes and influenced the carbohydrate content and trehalase activity in the aphids.

Discussion: The number of offspring produced by the second-generation aphids was significantly reduced under mixed heavy metal treatment, but it was not caused by changes in the vitellogenin (Vg) content. These related results provide new avenues for further exploration of plant responses to mixed heavy metal stress, pest control, and management of heavy metal pollution.

Aim: The primary aim was to assess the efficacy of self-paced sprint interval training (SIT) with low-volume high-intensity interval training (LV-HIIT) when performed without encouragement on improving cardiorespiratory fitness (CRF). A secondary aim was to explore whether the effort exerted during protocols [power output (PO) and heart rate (HR)] influenced the change in CRF.

Methods: In a randomised cross-over design, 82 previously inactive adults (m/f: 26/56, 28 ± 10 years, BMI 25 ± 3 kg m^-2) undertook 6-weeks of self-paced SIT (4-8 × 30 s with 120 s recovery) or LV-HIIT (6-10 × 1 min with 1 min recovery) separated by a 4-week washout period. Sessions were completed 3×/week using WattBikes, and a target of >80% HRmax was suggested during the intervals. Markers of cardio-metabolic health were assessed before and after each intervention.

Results: Training increased VO_2peak (SIT +3.1 ± 0.4 mL kg^-1 min^-1, LV-HIIT +2.7 ± 1.2 mL kg^-1 min^-1, P < 0.001) and decreased body fat % (P = 0.002), aortic pulse wave velocity (P = 0.002) and glucose tolerance 120 min following an oral glucose tolerance test (P = 0.024), with no difference between protocols (P > 0.05). When grouping participants into tertiles based on HR and PO responses (n = 27), those achieving a low HR had similar changes in VO_2peak compared to the high HR group in both interventions (P > 0.05). For LV-HIIT, participants in the highest tertile for peak PO had a greater change in VO_2peak compared to all other participants (Low 1.8 ± 4.1 mL kg^-1 min^-1, Medium 1.9 ± 3.3 mL kg^-1 min^-1, High 4.3 ± 3.6 ml kg^-1 min^-1, P = 0.020).

Discussion: Six-weeks of self-paced SIT and LV-HIIT induce comparable improvements in CRF, body composition, arterial stiffness and glucose tolerance. Importantly, higher HR did not elicit superior changes in CRF, but PO achieved during LV-HIIT may influence improvements.

Background: Chronic kidney disease (CKD) has now reached pandemic proportions but risk prediction towards end-stage kidney disease (ESKD) remains challenging. Kidney fibrosis is a key determinant in the transition from CKD to ESKD. In this prospective study, we investigated the prognostic significance of urinary Marinobufagenin (uMBG), a cardiotonic steroid with acknowledged pro-fibrotic activity, for stratifying the risk of CKD progression in individuals with non-advanced renal disease.

Methods: After baseline uMBG measurements, 108 CKD patients (eGFR 40.54 ± 17 mL/min/1.73 m²) were prospectively followed up to 24 months. The study (renal) endpoint was a composite of serum creatinine doubling, eGFR decline >25% from baseline values, or ESKD requiring chronic renal replacement therapy.

Results: During follow-up (mean 21 months), 32.4% of patients had progressive CKD. These individuals displayed almost halved baseline uMBG excretion as compared to others (p < 0.0001). At ROC analysis uMBG showed a remarkable diagnostic capacity on CKD progression (AUC 0.898) and patients with uMBG ≤310 pmol/L (Best ROC-derived cut-off) had a significantly faster progression to the endpoint (Log-rank 57.9; p < 0.0001). Restricted cubic splines fitting logistic and Cox-regression analyses revealed that the risk association between uMBG and CKD progression was best described by a curvilinear, inverse J-shaped trend, the highest risk associated with very low uMBG levels. This trend remained unaffected by adjustment for age, baseline eGFR, and 24 h-proteinuria.

Conclusion: In individuals with non-advanced CKD, very low urinary excretion of MBG reflects a more sustained risk of CKD progression over time. Validation studies are needed to generalize these findings in larger heterogeneous cohorts.

Breeding success and survival in colonial seabirds are influenced by nest location, physical surroundings, and external disturbances. Nest location may also directly or indirectly affect individual foraging behavior and physiological conditions, shaping reproductive success and survival. Despite these influences, few studies have integrated the analysis of nest location, behavior, and physiological status. In this study, we analyzed 20 black-tailed gulls (Larus crassirostris) nesting in the center of a colony within a protected area (Central Group, CG) and five gulls on the periphery outside the protected area, where human disturbance is frequent (Peripheral Group, PG). Using GPS movement trajectories and physiological indicators, we found that although clutch sizes were similar between the CG and PG, the PG exhibited shorter foraging trip durations, maximum distances from the nest, and a lower daily frequency of foraging trips. Antioxidant capacity did not differ between the groups; however, oxidation levels were lower in the PG. These behavioral and physiological differences associated with nest location may partly result from the incubation period influenced by human activity. The PG individuals remained in the peripheral group for at least 2 years (some for over 15 years), with all reproductive attempts failing, suggesting consistently low reproductive success. However, reduced foraging activity and lower oxidative stress levels reflect an energy-saving strategy that may mitigate the costs of repeated breeding failures. These findings suggest a potential life-history trade-off, in which individuals prioritize survival over reproductive success. This highlights how external disturbances and nest location can shape energy allocation strategies within a colony's peripheral-central distribution.

The three main conduits used for myocardial revascularization in patients with coronary artery disease (CAD) are the internal thoracic artery (ITA), radial artery (RA) and saphenous vein (SV). In coronary artery bypass grafting (CABG) conduits may be harvested with perivascular adipose tissue (PVAT) intact (pedicled) or removed (skeletonized). Various studies have shown that the patency rate of these bypass grafts may be affected by the preservation or removal of PVAT. Vasospasm is often encountered at harvesting, a condition that has both immediate and long term effects on graft performance. During surgery a variety of antispastic solutions are routinely used on conduits that have anti-contractile and/or vasorelaxant actions. Spasm may be abolished or reduced when PVAT is left intact at harvesting and this is particularly the case for the SV. The protective properties of PVAT are multifactorial, ranging from its mechanical properties in supporting the graft after implantation to the beneficial effect of adipocyte-derived factors. This review aims to outline the possible mechanisms through which preserved PVAT could alleviate vasospasm and improve conduit performance in CABG. Moreover, since preservation of PVAT reduces spasm at and after surgery this review also considers whether antispastic solutions are needed if conduits are harvested with PVAT intact.

Introduction: Imposing constraints such as limiting dribbling in smallsided games (SSGs) is known to increase physiological and locomotor demands. However, the long-term effects on physical adaptations remain unexplored. This experimental study aimed to compare the impact of free-play SSGs (freeD) and limited-dribbling SSGs (limitedD) in SSGs on the aerobic and anaerobic adaptations of youth basketball players.

Methods: Forty-five youth basketball players (aged 15.7 ± 0.6 years, with 4.2 ± 0.7 years of experience) were randomly assigned to two experimental groups (freeD and limitedD) and a control group (not exposed to SSG interventions). During the eight-week intervention, the experimental groups participated in additional SSG sessions twice a week, with session work time durations ranging from 12 to 16 min. Both experimental groups followed identical SSG formats, court dimensions, and training regimens, with the only difference being that one group participated in free play while the other group was prohibited from dribbling during progression. Aerobic capacity was assessed using the Yo-Yo Intermittent Recovery Test Level 1 (YYIRT), while the 30-second Wingate Test measured peak power output (PPO) and average power output (APO) at baseline and post-intervention. Statistical analysis was conducted using a mixed ANOVA to examine the interactions between time and group.

Results: Comparisons of YYIRT between groups at post-intervention revealed that limitedD performed significantly better than both freeD (p = 0.035; d = 1.038) and the control group (p < 0.001; d = 2.050), while freeD also showed significantly better performance (p = 0.021; d = 0.082) than the control group. Regarding PPO, limitedD was significantly better than the control group (p = 0.043; d = 0.943). Finally, for APO, limitedD was significantly better than both freeD (p = 0.043; d = 0.928) and the control group (p < 0.001; d = 1.793), while freeD also exhibited significantly better performance than the control group (p = 0.046; d = 0.036).

Conclusions: Limiting dribbling in basketball SSGs is more effective than free play. This makes it a potentially valuable strategy for designing SSGs in basketball training. Coaches may consider incorporating limited-dribbling conditions into SSGs to boost the intensity of training sessions, improve cardiovascular endurance, and enhance anaerobic power.

Hypothyroidism is a common thyroid dysfunction with a higher prevalence in women. Impairments in the regulation of basal metabolism, small intestine nutrient transporter, dyslipidemia, and disruption in circadian clocks have been associated with the thyroid disorder. This study aimed to evaluate whether hypothyroidism affects the small intestine circadian clock and the daily expression pattern of gut nutrient transporters in female mice. Adult female C57BL/6J mice were subjected to hypothyroidism by the administration of methimazole (0.1%) and sodium perchlorate (1%) in drinking water for 45 days. After, the animals were subdivided and euthanized every 4 h over the 24 h period under deep anesthesia. The proximal small intestine segment was collected and immediately frozen for gene expression analysis of circadian core clock components (Bmal1, Per2, Cry1, and Nr1d1) and nutrient transporters by RT-qPCR. The daily protein content of nutrient transporters involved in the absorption of the products of hydrolysis of lipids, proteins, and carbohydrates was evaluated over 24 h in isolated small intestinal epithelium by Western blotting. The expression of clock genes and protein content of nutrients transporters in the jejunum of control female mice exhibited a well-defined circadian rhythmicity, while no rhythmic oscillation over 24 h was observed for the transporter transcripts. Hypothyroidism abolished the circadian rhythmicity of circadian clock, punctually reduced the transcript content of Slc2a5 (GLUT5) at ZT12 and Slc2a2 (GLUT2) at ZT4, and disrupted the circadian oscillation of L-FABP, CD36, PEPT1, and GLUT2 protein contents in the small intestine of female mice. In conclusion, our findings indicate that thyroid hormones modulate the circadian clock of small intestine and the daily rhythmicity of components related to absorptive processes in female mice. Moreover, our data suggest that the mechanisms triggered by thyroid hormones involve posttranscriptional and/or translational modifications of proteins related to lipid, protein, and carbohydrate absorption. Together, these data contribute to the general comprehension of metabolic alterations often observed in hypothyroidism and have far-reaching implications at clinical levels considering the higher worldwide prevalence of hypothyroidism in women and its association with obesity and metabolic syndrome.

Precision-cut lung slices (PCLS) are commonly used as an ex vivo model to study lung fibrosis; however, traditional models lack immune cell infiltration, including the recruitment of monocytes and macrophages, which are critical for inflammation and fibrosis. To address this limitation, we developed novel autologous PCLS-immune co-culture models that better replicate the processes of inflammation, repair, and immune cell recruitment associated with fibrosis. Fibrotic responses to nicotine, cigarette smoke extract (CSE), and a fibrosis-inducing cocktail (FC) were first evaluated in PCLS containing only tissue-resident macrophages, with upregulation of α-SMA-expressing fibroblasts confirmed by immunofluorescence and Western blotting, and collagen deposition quantified using Sirius Red staining. To study macrophage recruitment, we employed an indirect co-culture model using transwells to approximate blood vessel function. Chemotactic studies revealed increased migration of autologous bone marrow-derived macrophages (BMDMs) toward and infiltration into CSE-injured PCLS. In a direct co-culture model simulating the repair phase of fibrosis, PCLS exposed to CSE and FC showed further increased collagen deposition in the presence of autologous BMDMs, but not heterologous ones. These findings suggest that our novel PCLS-immune co-culture models provide a platform for studying macrophage involvement in fibrosis and offer potential for developing macrophage-targeted therapeutic strategies in pulmonary fibrosis.