Sebastián Del Rosso

This study examined the association between technical–tactical ruck variables and the probability of defeat in international rugby union. Six variables (Pitch Territory, Number of Phases, Match Half, Player Type, Gainline Progression/Ruck Position, and Number of Players in the Ruck) were recorded from 2575 rucks across 26 international matches played by the Spanish national team. The binary logistic regression model displayed a significant overall fit (χ² = 137.247, df = 9, p < 0.001, Nagelkerke R² = 0.0692, AUC = 0.6208), achieving 57.98% global accuracy. A high Number of Phases (OR = 3.265 for ≥7 Phases), playing within Own Territory (OR = 1.481), operating Behind Gainline (OR = 1.478), or On Gainline (OR = 1.369), and actions during the Second Half (65.7%) compared to the First Half (54.5%) were significantly associated with higher odds of defeat. Conversely, the post hoc GLMM sensitivity check showed that the associations for these variables remained broadly consistent, while indicating that the exclusive involvement of Backs was associated with the highest estimated probability of defeat among the Player Type categories (64.4% vs. 57.2% for Forwards), and that the involvement of ≥4 players in the ruck became statistically significant in the mixed-effects model after accounting for match-level clustering and was associated with a higher estimated probability of defeat. In conclusion, Number of Phases, Pitch Territory, Gainline Progression, and the quantity and Player Type involved are significantly associated with defeat, aligning with specific contact exposure environments.

The study of type 2 diabetes mellitus (T2DM) pathophysiology relies mainly on the use of animal models, the most common of which involves the consumption of high-fat diets comprising 60% calories from fat. Although these models reproduce the onset and most complications associated with T2DM, they do not accurately mimic human dietary patterns, as they lack the addition of carbohydrates such as fructose in drinking water. The aim of this study was to develop a mouse model for studying complications related to T2DM. To this end, male C57BL/6 mice were fed a medium-fat diet (34.5% kcal from fat), given 20% fructose in drinking water, and injected with a single low dose of streptozotocin (STZ; 100 mg/kg) (D + T). At week 20, D + T mice exhibited significant weight gain, elevated fasting blood glucose levels, and the development of insulin resistance compared with control mice. Furthermore, the circulating levels of liver enzymes (GPT, GOT, and alkaline phosphatase), total cholesterol, and LDL increased. Multi-organ damage, including reduced pancreatic islet size and number, severe hepatic steatosis, inflammatory infiltration in visceral adipose tissue, and cardiac and renal dysfunction, was also detected. The proposed model replicates T2DM-associated complications in young mice by combining a medium-fat diet with fructose and STZ.

Chagas disease, caused by Trypanosoma cruzi , is endemic to Latin America and is characterized by chronic inflammation of cardiac tissues due to parasite persistence. Hypoxia within infected tissues may trigger the stabilization of HIF-1 and be linked to ATP release. Extracellular ATP exhibits microbicidal effects but is scavenged by CD39 and CD73 ectonucleotidases, which ultimately generate adenosine (ADO), a potent immunosuppressor. Here, we comprehensively study the importance of HIF-1 stabilization and the CD39/CD73/ADO axis, on CD4 ⁺ T cells with the cytotoxic phenotype, in facilitating the persistence of T. cruzi . Myocardial infection induces prominent areas of hypoxia, which is concomitant with HIF-1α stabilization in T cells and linked to early expansion of CD39 ⁺ CD73 ⁺ CD4 ⁺ T cell infiltrating population. Functional assays further demonstrate that HIF-1 stabilization and CD73 activity are associated with impaired CD4 ⁺ T cell cytotoxic potential. RNA-Seq analysis reveals that HIF-1 and purinergic signaling pathways are overrepresented in cardiac tissues of patients with end-stage Chagas disease. The findings highlight a major effect of purinergic signaling on CD4 ⁺ T cells with potential cytotoxic capacity in the setting of T. cruzi infection and have translational implications for therapy.

We investigated the influence of anaerobic speed reserve (ASR) on post-activation performance enhancement (PAPE). Twenty-two endurance runners and triathletes were evaluated for maximum sprinting speed (MSS) and countermovement jump (CMJ) before (non-fatigued) and after (fatigued) an incremental running test. They were allocated in LASR (low-ASR) and HASR (high-ASR) groups for comparisons between conditions. HASR showed greater CMJ and MSS (both p ≤ 0.005) performances, with enhanced CMJ in fatigued condition ( p ≤ 0.008). Significant correlations were found between ASR, CMJ, and MSS in both conditions ( p ≤ 0.01) for the entire sample, and between ∆CMJ and ∆MSS ( p ≤ 0.001) in LASR. Our results show that ASR profile influences PAPE.

Background: Supramaximal constant work rate tests (CWR) elicit intense hyperventilation, thus potentially up-shifting ventilation (⩒_E)-to-carbon dioxide (CO₂) responses when compared to graded exercise tests (GXT) in athletes. We predicted higher ventilatory efficiency on supramaximal CWR using a new method, challenging the classic orthodox interpretation of an increased ⩒_E-⩒CO₂ as ventilatory inefficiency. This misinterpretation could make difficult to differentiate between physiological hyperventilation from heart disease conditions in athletes. Methods: On different days, a GXT and a CWR at 110% of the maximal velocity achieved in the GXT were performed. Twenty-seven athletes completed the two tests and were compared for usual (linear regression) and log-transformed new variables for ventilatory efficiency through paired t-Student statistics. Results: The ⩒_E-⩒CO₂ slope (31.4 ± 4.9 vs. 26.2 ± 3.4, p < .001), ⩒_E-⩒CO₂ intercept (7.2 ± 7.5 vs. 2.8 ± 4.2, p < .007), ⩒_E/⩒CO₂ nadir (33.0 ± 3.6 vs. 25.4 ± 2.2, p < .001), ⩒CO₂-log⩒_E slope (10.8 ± 2.9 vs. 6.9 ± 2.2 L_*logL^-1, p < .001), and η⩒^E (36.0 ± 12 vs. 22.8 ± 8.1%, p < .001) values were all significantly higher in the CWR compared to the GXT. We registered a bi-modal nadir response for ⩒_E/⩒CO₂ on CWR for 22 out of 27 subjects for the first time. A weak association was observed between ⩒_E/⩒CO₂ nadir (coefficient of determination ~ 27%) and time to exhaustion. Conclusions: The new method allows us to improve the quantification and interpretation of ventilatory efficiency in athletes, avoiding misinterpretation due to the up-shifting elicited by the usual ⩒_E-⩒CO₂ slope and ⩒_E/⩒CO₂ nadir indices, which may be confounded with ventilatory inefficiency. This study suggests that ventilatory changes underpin better ventilatory efficiency during CWR.

"The Limitations of Systematic Reviews With Meta-Analyses in Sport Science" published on 24 Apr 2024 by Human Kinetics.

Introduction: We have acquired significant knowledge regarding the pathogenesis of severe acute respiratory syndrome caused by coronavirus 2 (SARS-CoV-2). However, the underlying mechanisms responsible for disease recovery still need to be fully understood.Methods: To gain insights into critical immune markers involved in COVID-19 etiopathogenesis, we studied the evolution of the immune profile of peripheral blood samples from patients who had recovered from COVID-19 and compared them to subjects with severe acute respiratory illness but negative for SARS-CoV-2 detection (controls). In addition, linear and clustered correlations between different parameters were determined.Results: The data obtained revealed a significant reduction in the frequency of inflammatory monocytes (CD14+CD16+) at hospital discharge vs. admission. Remarkably, nitric oxide (NO) production by the monocyte compartment was significantly reduced at discharge. Furthermore, interleukin (IL)-6 plasma levels were negatively correlated with the frequency of NO+CD14+CD16+ monocytes at hospital admission. However, at the time of hospital release, circulating IL-6 directly correlated with the NO production rate by monocytes. In line with these observations, we found that concomitant with NO diminution, the level of nitrotyrosine (NT) on CD8 T-cells significantly diminished at the time of hospital release. Considering that purinergic signaling constitutes another regulatory system, we analyzed the kinetics of CD39 and CD73 ectoenzyme expression in CD8 T-cells. We found that the frequency of CD39+CD8+ T-cells significantly diminished while the percentage of CD73+ cells increased at hospital discharge. In vitro, IL-6 stimulation of PBMCs from COVID-19 patients diminished the NT levels on CD8 T-cells. A clear differential expression pattern of CD39 and CD73 was observed in the NT+ vs. NT-CD8+ T-cell populations.Discussion: The results suggest that early after infection, IL-6 controls the production of NO, which regulates the levels of NT on CD8 T-cells modifying their effector functions. Intriguingly, in this cytotoxic cell population, the expression of purinergic ectoenzymes is tightly associated with the presence of nitrated surface molecules. Overall, the data obtained contribute to a better understanding of pathogenic mechanisms associated with COVID-19 outcomes.

Objectives: The present study aimed to identify optimal inflammatory biomarkers involved in cardiorenal risk in response to major lifestyle factors. Methods: One hundred and twenty-nine adults aged 35–77 years participated voluntarily from 2017 to 2019 (Córdoba, Argentina) in a cross-sectional study to collect sociodemographic, clinical, and lifestyle data. Blood biomarkers (different cytokines, monocyte chemoattractant protein-1 [MCP-1], and high-sensitivity C-reactive protein [hs-CRP]) were measured using standard methods and then evaluated by principal component analysis and structural equation modeling (SEM) according to Mediterranean diet adherence, physical activity level, and waist circumference, while cardiorenal risk involved blood diastolic pressure, HDL-cholesterol, triacylglycerols, creatinine, and glycosylated hemoglobin. Results: A principal component included TNF-α (tumor necrosis factor-alpha), IL-8 (interleukin-8), IL-6 (interleukin-6), hs-CRP, and MCP-1, with absolute rotated factor loadings >0.10. SEM showed that IL-6 (β=0.38, 95 % IC=0.08–0.68), hs-CRP (β=0.33, 95 % IC=0.17–0.48), and TNF-α (β=0.22, 95 % IC=0.11–0.32) were the mediators that better explained an inflammatory profile positively related to waist circumference (β=0.77, 95 % IC=0.61–0.94). Moreover, this profile was associated with an increased cardiorenal risk (β=0.78, 95 % IC=0.61–0.94), which was well-defined by the variable used. Conclusions: Immune mediators are key elements in profiling the cardiorenal risk associated with lifestyle factors, for which the combination of hs-CRP, IL-6, and TNF-α has emerged as a robust indicator. This work reaffirms the need for biomarker optimization for early diagnosis and risk assessment.