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Ítem Exercise intolerance in volume overload heart failure is associated with low carotid body mediated chemoreflex drive(2021) David C. Andrade; Esteban Díaz‑Jara; Camilo Toledo; Karla G. Schwarz; Katherin V. Pereyra; Hugo S. Díaz; Noah J. Marcus; Fernando C. Ortiz; Angélica P. Ríos‑Gallardo; Domiziana Ortolani; Rodrigo Del RioMounting an appropriate ventilatory response to exercise is crucial to meeting metabolic demands, and abnormal ventilatory responses may contribute to exercise-intolerance (EX-inT) in heart failure (HF) patients. We sought to determine if abnormal ventilatory chemoreflex control contributes to EX-inT in volume-overload HF rats. Cardiac function, hypercapnic (HCVR) and hypoxic (HVR) ventilatory responses, and exercise tolerance were assessed at the end of a 6 week exercise training program. At the conclusion of the training program, exercise tolerant HF rats (HF + EX-T) exhibited improvements in cardiac systolic function and reductions in HCVR, sympathetic tone, and arrhythmias. In contrast, HF rats that were exercise intolerant (HF + EX-inT) exhibited worse diastolic dysfunction, and showed no improvements in cardiac systolic function, HCVR, sympathetic tone, or arrhythmias at the conclusion of the training program. In addition, HF + EX-inT rats had impaired HVR which was associated with increased arrhythmia susceptibility and mortality during hypoxic challenges (~ 60% survival). Finally, we observed that exercise tolerance in HF rats was related to carotid body (CB) function as CB ablation resulted in impaired exercise capacity in HF + EX-T rats. Our results indicate that: (i) exercise may have detrimental effects on cardiac function in HF-EX-inT, and (ii) loss of CB chemoreflex sensitivity contributes to EX-inT in HF.Ítem Exercise intolerance in volume overload heart failure is associated with low carotid body mediated chemoreflex drive(2021) David C. Andrade; Esteban Díaz‑Jara; Camilo Toledo; Karla G. Schwarz; Katherin V. Pereyra; Hugo S. Díaz; Noah J. Marcus; Fernando C. Ortiz; Angélica P. Ríos‑Gallardo; Domiziana Ortolani; Rodrigo Del RioMounting an appropriate ventilatory response to exercise is crucial to meeting metabolic demands, and abnormal ventilatory responses may contribute to exercise‑intolerance (EX‑inT) in heart failure (HF) patients. We sought to determine if abnormal ventilatory chemoreflex control contributes to EX‑inT in volume‑overload HF rats. Cardiac function, hypercapnic (HCVR) and hypoxic (HVR) ventilatory responses, and exercise tolerance were assessed at the end of a 6 week exercise training program. At the conclusion of the training program, exercise tolerant HF rats (HF + EX‑T) exhibited improvements in cardiac systolic function and reductions in HCVR, sympathetic tone, and arrhythmias. In contrast, HF rats that were exercise intolerant (HF + EX‑inT) exhibited worse diastolic dysfunction, and showed no improvements in cardiac systolic function, HCVR, sympathetic tone, or arrhythmias at the conclusion of the training program. In addition, HF + EX‑inT rats had impaired HVR which was associated with increased arrhythmia susceptibility and mortality during hypoxic challenges (~ 60% survival). Finally, we observed that exercise tolerance in HF rats was related to carotid body (CB) function as CB ablation resulted in impaired exercise capacity in HF + EX‑T rats. Our results indicate that: (i) exercise may have detrimental effects on cardiac function in HF‑EX‑inT, and (ii) loss of CB chemoreflex sensitivity contributes to EX‑inT in HF.Ítem Effects of enriched‑potassium diet on cardiorespiratory outcomes in experimental non‑ischemic chronic heart failure(2021) Karla G. Schwarz; Katherin V. Pereyra; Camilo Toledo; David C. Andrade; Hugo S. Díaz; Esteban Díaz‑Jara; Domiziana Ortolani; Angélica Rios‑Gallardo; Paulina Arias; Alexandra Las Heras; Ignacio Vera; Fernando C. Ortiz; Nibaldo C. Inestrosa; Carlos P. Vio; Rodrigo Del RioBackground: Chronic heart failure (CHF) is a global health problem. Increased sympathetic outflow, cardiac arrhythmogenesis and irregular breathing patterns have all been associated with poor outcomes in CHF. Several studies showed that activation of the renin-angiotensin system (RAS) play a key role in CHF pathophysiology. Interestingly, potassium (K+) supplemented diets showed promising results in normalizing RAS axis and autonomic dysfunction in vascular diseases, lowering cardiovascular risk. Whether subtle increases in dietary K+ consumption may exert similar effects in CHF has not been previously tested. Accordingly, we aimed to evaluate the effects of dietary K+ supplementation on cardiorespiratory alterations in rats with CHF. Methods: Adult male Sprague–Dawley rats underwent volume overload to induce non-ischemic CHF. Animals were randomly allocated to normal chow diet (CHF group) or supplemented K+ diet (CHF+K+ group) for 6 weeks. Cardiac arrhythmogenesis, sympathetic outflow, baroreflex sensitivity, breathing disorders, chemoreflex function, respiratory–cardiovascular coupling and cardiac function were evaluated. Results: Compared to normal chow diet, K+supplemented diet in CHF significantly reduced arrhythmia incidence (67.8 ± 15.1 vs. 31.0 ± 3.7 events/hour, CHF vs. CHF+K+), decreased cardiac sympathetic tone (ΔHR to propranolol:− 97.4 ± 9.4 vs. − 60.8 ± 8.3 bpm, CHF vs. CHF+K+), restored baroreflex function and attenuated irregular breathing patterns. Additionally, supplementation of the diet with K+ restores normal central respiratory chemoreflex drive and brogates pathological cardio-respiratory coupling in CHF rats being the outcome an improved cardiac function. Conclusion: Our findings support that dietary K+ supplementation in non-ischemic CHF alleviate cardiorespiratory dysfunction.Ítem Cardiac Autonomic Modulation in Response to Muscle Fatigue and Sex Differences During Consecutive Competition Periods in Young Swimmers: A Longitudinal Study(2021) Matías Castillo-Aguilar; Pablo Valdés-Badilla; Tomás Herrera-Valenzuela; Eduardo Guzmán-Muñoz; Pedro Delgado-Floody; David Cristóbal Andrade; Michele M. Moraes; Rosa M. E. Arantes; Cristian Núñez-EspinosaObjective: To study the differences in cardiac autonomic modulation in response to muscle fatigue caused by high-intensity exercise during two consecutive competition periods in young swimmers. Methods: Twenty-six competitive swimmers, selected by their training volume, were separated in two groups, females (n = 12 [46%], age: 13.5 ± 1.4 years) and males (n = 14 [54%], age: 13.9 ± 1.7 years), aged between 10 and 16 years, were evaluated five times as follow: (i) 21 days before the first competition (t-0); (ii) two days before (t-1; t-3); and (iii) two days after (t-2; t-4) of the first and second competitions. Morphological measurements (body mass, percentage of total body fat and height), blood pressure, power, and resting heart rate variability (RR with Polar band) were recorded before and after Wingate test at each time. Results: Body fat was higher in females compared to males. However, no differences were found in other morphological parameters. An intra-subject analysis grouped by sex in cardiovascular parameters shows longitudinal variations in systolic pressure and mean pressure among females. Additionally, females depicted higher, very low frequency (VLF, which is intrinsically generated by the heart and strongly associated with emotional stress) after physical fatigue compared to males at t-1. Further, before the competition, the high frequency (HF) component of HRV (parasympathetic drive) was higher in males than females at t-0 and t-4. Conclusion: Our data revealed that males displayed greater parasympathetic reactivity after an anaerobic muscle fatigue test during their competition periods. Contrarily, females had a less cardiac autonomic modulation when comparing the pre-post Wingate test after two consecutive competition periods.Ítem Dietary supplementation of a sulforaphane-enriched broccoli extract protects the heart from acute cardiac stress(2020) Katherin V. Pereyra; David C. Andrade; Camilo Toledo; Karla G. Schwarz; Atenea Uribe-Ojeda; Angélica P. Ríos-Gallardo; Rodrigo A. Quintanilla; Samuel Contreras; Andrea Mahn; Rodrigo Del RioCardiac arrythmias play a critical role in several pathological conditions. Importantly, increased arrhythmic risk is associated with systemic oxidative stress and activation of the autonomic nervous system. Thus, we hypothesized that dietary antioxidant supplementation may help in reducing cardiac stress-induced arrhythmias. Sulforaphane (SFN), an isothiocyanate present in Brassicaceaes, is recognized as a powerful health-promoting compound with known antioxidant properties. Then, we aimed to generate a broccoli extract (BE) enriched in SFN and determine whether oral BE supplementation induced cardio-protection during acute cardiac stress in rats. BE decreases cardiac sympathetic drive and increases parasympathetic cardiac modulation as evidenced by heart rate variability (HRV) shifts. In addition, isoproterenol-induced cardiac stress (a sympathomimetic agent) induced a ~ 4-fold increase in arrhythmia incidence and this effect was almost completely abolished by BE treatment. In conclusion, dietary supplementation with a BE regulates cardiac autonomic drive and protects the heart from acute cardiac stress.Ítem Inhibition of Brainstem Endoplasmic Reticulum Stress Rescues Cardiorespiratory Dysfunction in High Output Heart Failure(2021) Díaz, H.S.; Andrade, D.C.; Toledo, C.; Schwarz, K.G.; Pereyra, K.V.; Díaz-Jara, E.; Marcus. N.J.; Del Rio, R.Recent evidence shows that chronic activation of catecholaminergic neurons of the rostral ventrolateral medulla is crucial in promoting autonomic imbalance and cardiorespiratory dysfunction in high output heart failure (HF). Brainstem endoplasmic reticulum stress (ERS) is known to promote cardiovascular dysfunction; however, no studies have addressed the potential role of brainstem ERS in cardiorespiratory dysfunction in high output HF. In this study, we assessed the presence of brainstem ERS and its potential role in cardiorespiratory dysfunction in an experimental model of HF induced by volume overload. High output HF was surgically induced via creation of an arterio-venous fistula in adult male Sprague-Dawley rats. Tauroursodeoxycholic acid (TUDCA), an inhibitor of ERS, or vehicle was administered intracerebroventricularly for 4 weeks post-HF induction. Compared with vehicle treatment, TUDCA improved cardiac autonomic balance (LFHRV/HFHRV ratio, 3.02±0.29 versus 1.14±0.24), reduced cardiac arrhythmia incidence (141.5±26.7 versus 35.67±12.5 events/h), and reduced abnormal respiratory patterns (Apneas: 11.83±2.26 versus 4.33±1.80 events/h). TUDCA administration (HF+Veh versus HF+TUDCA, P<0.05) attenuated cardiac hypertrophy (HW/BW 4.4±0.3 versus 4.0±0.1 mg/g) and diastolic dysfunction. Analysis of rostral ventrolateral medulla gene expression confirmed the presence of ERS, inflammation, and activation of renin-angiotensin system pathways in high output HF and showed that TUDCA treatment completely abolished ERS and ERS-related signaling. Taken together, these results support the notion that ERS plays a role in cardiorespiratory dysfunction in high output HF and more importantly that reducing brain ERS with TUDCA treatment has a potent salutary effect on cardiac function in this model.Ítem Plyometric jump training effects on the physical fitness of individual-sport athletes: A systematic review with meta-analysis(2021) Sole, S.; Ramírez-Campillo, R.; Andrade, D.C.; Sanchez-Sanchez, J.Background: The aim of this study is to conduct a systematic review with meta-analysis to explore the effects of plyometric jump training (PJT) on the physical fitness of individual sport athletes (ISA). Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched through PubMed, Web of Science, and SCOPUS electronic databases. We included controlled studies that incorporated a PJT intervention among ISA (with no restriction for age or sex), that included a pre-to-post intervention assessment of physical fitness (e.g., sprint; jump). From the included studies, relevant data (e.g., PJT and participants characteristics) was extracted. We assessed the methodological quality of the included studies using the PEDro scale. Using a random-effects model, meta-analyses for a given outcome was conducted. Means and standard deviations for a measure of pre-post-intervention physical fitness from the PJT and control groups were converted to Hedges’ g effect size (ES). Heterogeneity was assessed using the I2 statistic. The risk of bias was explored using the extended Egger’s test. The statistical significance threshold was set at p < 0.05. Moderator analyses were conducted according to the sex, age and sport background of the athletes. Results: Twenty-six studies of moderate-high methodological quality were included (total participants, n = 667). Compared to controls, PJT improved vertical jump (ES = 0.49; p < 0.001; I = 0.0%), linear sprint (ES = 0.23; p = 0.032; I2 = 10.9%), maximal strength (ES = 0.50; p < 0.001; I2 = 0.0%) and endurance performance (ES = 0.30; p = 0.028; I2 = 11.1%). No significant effect was noted for sprint with change of direction (ES = 0.34; p = 0.205; I2 = 70.9%). Athlete’s sex, age and sport background had no modulator role on the effect of PJT on vertical jump, linear sprint, maximal strength and endurance performance. Among the included studies, none reported adverse effects related to the PJT intervention. Conclusions: PJT induces small improvements on ISA physical fitness, including jumping, sprinting speed, strength and endurance.