RESUMEN
PURPOSE: This study investigated the impact of four weeks of age-dependent detraining on army soldiers' cardiorespiratory fitness and maximal and explosive strength. METHODS: Fourteen volunteer tactical athletes participated, divided into two age groups (20 to 29 and 30 to 40 years). Before and after the detraining period, we assessed their anthropometric measurements (weight, height, body mass index, fat mass, and fat-free mass), cardiorespiratory fitness (maximal oxygen uptake [VO2max] and ventilatory thresholds [VT1 and VT2]), and kinematic properties during a single-leg counter-moving jump (CMJ) test for both the dominant and non-dominant legs. Two-way ANOVA followed by the Holm-Sidak post hoc test was used. RESULTS: The anthropometric and cardiovascular variables did not show significant differences between the groups. However, both groups exhibited a significantly reduced maximum time and speed at the VO2max. Furthermore, the flight time and maximum height during the CMJ significantly decreased in the non-dominant leg for both age groups. Notably, the dominant leg's concentric impulse (CI) significantly reduced during the CMJ, but this effect was observed only in the 30-40 age group. There were significant differences between the two age groups. CONCLUSIONS: Our findings suggest that four weeks of detraining negatively impacts aerobic fitness and muscular strength, independently of age. However, the dominant leg may be more susceptible to detraining effects in army soldiers aged 30-40. Furthermore, as a perspective, our results strongly suggest that a detraining period could affect successful missions (aerobic performance deterioration), as well as promote a muscle imbalance between the legs, which could encourage muscle injuries and endanger combat missions.
RESUMEN
Swimmer athletes showed a decreased ventilatory response and reduced sympathetic activation during peripheral hypoxic chemoreflex stimulation. Based on these observations, we hypothesized that swimmers develop a diminished cardiorespiratory coupling due to their decreased hypoxic peripheral response. To resolve this hypothesis, we conducted a study using coherence time-varying analysis to assess the cardiorespiratory coupling in swimmer athletes. We recruited 12 trained swimmers and 12 control subjects for our research. We employed wavelet time-varying spectral coherence analysis to examine the relationship between the respiratory frequency (Rf ) and the heart rate (HR) time series during normoxia and acute chemoreflex activation induced by five consecutive inhalations of 100% N2 . Comparing swimmers to control subjects, we observed a significant reduction in the hypoxic ventilatory responses to N2 in swimmers (0.012 ± 0.001 vs. 0.015 ± 0.001 ΔVE /ΔVO2 , and 0.365 ± 0.266 vs. 1.430 ± 0.961 ΔVE /ΔVCO2 /ΔSpO2 , both p < 0.001, swimmers vs. control, respectively). Furthermore, the coherence at the LF cutoff during hypoxia was significantly lower in swimmers compared to control subjects (20.118 ± 3.502 vs. 24.935 ± 3.832 area under curve [AUC], p < 0.012, respectively). Our findings strongly indicate that due to their diminished chemoreflex control, swimmers exhibited a substantial decrease in cardiorespiratory coupling during hypoxic stimulation.
Asunto(s)
Atletas , Hipoxia , Humanos , Frecuencia Cardíaca , Frecuencia Respiratoria , Factores de TiempoRESUMEN
BACKGROUND: Translation strategies are commonly used for qualitative interview data to bridge language barriers. Inconsistent translation of interviews can lead to conceptual inequivalence, where meanings of participants' experiences are distorted, threatening scientific rigor. OBJECTIVES: Our objective is to describe a systematic method developed to analyze multilingual, qualitative interview data while maintaining the original language of the transcripts. METHODS: A literature review of translation strategies, cross-language, and multilingual qualitative research was conducted. Combined with criteria for qualitative content analysis and trustworthiness, the methodology was developed and used for a qualitative descriptive study. RESULTS: The study had interview data in both English and Spanish. The research team consisted of both native Spanish and English speakers, who were grouped based on language. Verbatim transcription of data occurred in the original languages. All codes were kept in English, allowing the research team to view the data set as a whole. Two researchers within each group coded each transcript independently before reaching a consensus. The entire research team discussed all transcripts, and finally, major themes were determined. Participants' quotes remained in the original language for publication, with an English translation included when needed. DISCUSSION: Analyzing transcripts in the original language brought forth cultural themes that otherwise may have been overlooked. This methodology promotes conceptual equivalence and trustworthiness that is paramount in cultural, linguistic, and social determinants of health research to advance health equity.
Asunto(s)
Lenguaje , Multilingüismo , Humanos , Lingüística , Investigación Cualitativa , Barreras de ComunicaciónRESUMEN
Introduction: The cardiorespiratory optimal point (COP) represents the lowest minute ventilation to oxygen consumption ratio (VE/VO2) and can be estimated during a CPET at submaximal intensity when an exercise test until volitional fatigue is not always advisable (i.e., a conflict zone where you cannot be confident of the security because near-competition, off-season, among other). COP's physiological components have not been wholly described yet. Therefore, this study seeks to identify the determinants of COP in highly trained athletes and its influence on maximum and sub-maximum variables during CPET through principal c omponent analysis (PCA) (explains the dataset's variance). Methods: Female (n = 9; age, 17.4 ± 3.1 y; maximal VO2 [VO2max]), 46.2 ± 5.9 mL/kg/min) and male (n = 24; age, 19.7 ± 4.0 y; VO2max, 56.1 ± 7.6 mL/kg/min) athletes performed a CPET to determine the COP, ventilatory threshold 1 (VT1) and 2 (VT2), and VO2max. The PCA was used to determine the relationship between variables and COP, explaining their variance. Results: Our data revealed that females and males displayed different COP values. Indeed, males showed a significant diminished COP compared to the female group (22.6 ± 2.9 vs. 27.2 ±3.4 VE/VO2, respectively); nevertheless, COP was allocated before VT1 in both groups. Discussion: PC analysis revealed that the COP variance was mainly explained (75.6%) by PC1 (expired CO2 at VO2max) and PC2 (VE at VT2), possibly influencing cardiorespiratory efficiency at VO2max and VT2. Our data suggest that COP could be used as a submaximal index to monitor and assess cardiorespiratory system efficiency in endurance athletes. The COP could be particularly useful during the offseason and competitive periods and the return to the sports continuum.
RESUMEN
Among the people most affected by coronavirus disease 2019 (COVID-19) are those suffering from hypertension (HTN). However, pharmacological therapies for HTN are ineffective against COVID-19 progression and severity. It has been proposed that exercise training (EX) could be used as post-COVID treatment, which does not rule out the possible effects during hospitalization for COVID-19. Therefore, we aimed to determine the impact of supervised EX on HTN patients with COVID-19 during hospitalization. Among a total of 1,508 hospitalized patients with COVID-19 (confirmed by PCR), 439 subjects were classified as having HTN and were divided into two groups: EX (n = 201) and control (n = 238) groups. EX (3-4 times/wk during all hospitalizations) consisted of aerobic exercises (15-45 min; i.e., walking); breathing exercises (10-15 min) (i.e., diaphragmatic breathing, pursed-lip breathing, active abdominal contraction); and musculoskeletal exercises (8-10 sets of 12-15 repetitions/wk; lifting dumbbells, standing up and sitting, lumbar stabilization). Our data revealed that the EX (clinician: patient, 1:1 ratio) intervention was able to improve survival rates among controlled HTN patients with COVID-19 during their hospitalization when compared with the control group (chi-squared: 4.83; hazard ratio: 1.8; 95% CI: 1.117 to 2.899; P = 0.027). Multivariate logistic regression analysis revealed that EX was a prognostic marker (odds ratio: 0.449; 95% CI: 0.230-0.874; P = 0.018) along with sex and invasive and noninvasive mechanical ventilation. Our data showed that an intrahospital supervised EX program reduced the mortality rate among patients with HTN suffering from COVID-19 during their hospitalization.NEW & NOTEWORTHY In the present study, we found that exercise training improves the survival rate in hypertensive patients with COVID-19 during their hospitalization period. Our results provide strong evidence for the therapeutic efficacy of exercise training as a feasible approach to improving the outcomes of patients with COVID-19 who suffer from hypertension during their hospitalization.
Asunto(s)
COVID-19 , Hipertensión , Humanos , Tasa de Supervivencia , Ejercicio Físico , Terapia por Ejercicio/métodosRESUMEN
BACKGROUND: Diabetes mellitus (DM) has glucose variability that is of such relevance that the appearance of vascular complications in patients with DM has been attributed to hyperglycemic and dysglycemic events. It is known that T1D patients mainly have glycemic variability with a specific oscillatory pattern with specific circadian characteristics for each patient. However, it has not yet been determined whether an oscillation pattern represents the variability of glycemic in T2D. This is why our objective is to determine the characteristics of glycemic oscillations in T2D and generate a robust predictive model. RESULTS: Showed that glycosylated hemoglobin, glycemia, and body mass index were all higher in patients with T2D than in controls (all p < 0.05). In addition, time in hyperglycemia and euglycemia was markedly higher and lower in the T2D group (p < 0.05), without significant differences for time in hypoglycemia. Standard deviation, coefficient of variation, and total power of glycemia were significantly higher in the T2D group than Control group (all p < 0.05). The oscillatory patterns were significantly different between groups (p = 0.032): the control group was mainly distributed at 2-3 and 6 days, whereas the T2D group showed a more homogeneous distribution across 2-3-to-6 days. CONCLUSIONS: The predictive model of glycemia showed that it is possible to accurately predict hyper- and hypoglycemia events. Thus, T2D patients exhibit specific oscillatory patterns of glycemic control, which are possible to predict. These findings may help to improve the treatment of DM by considering the individual oscillatory patterns of patients.
Asunto(s)
Diabetes Mellitus Tipo 2 , Hipoglucemia , Humanos , Diabetes Mellitus Tipo 2/complicaciones , Glucemia , GlucosaRESUMEN
Immersion water sports involve long-term apneas; therefore, athletes must physiologically adapt to maintain muscle oxygenation, despite not performing pulmonary ventilation. Breath-holding (i.e., apnea) is common in water sports, and it involves a decrease and increases PaO2 and PaCO2, respectively, as the primary signals that trigger the end of apnea. The principal physiological O2 sensors are the carotid bodies, which are able to detect arterial gases and metabolic alterations before reaching the brain, which aids in adjusting the cardiorespiratory system. Moreover, the principal H+/CO2 sensor is the retrotrapezoid nucleus, which is located at the brainstem level; this mechanism contributes to detecting respiratory and metabolic acidosis. Although these sensors have been characterized in pathophysiological states, current evidence shows a possible role for these mechanisms as physiological sensors during voluntary apnea. Divers and swimmer athletes have been found to displayed longer apnea times than land sports athletes, as well as decreased peripheral O2 and central CO2 chemoreflex control. However, although chemosensitivity at rest could be decreased, we recently found marked sympathoexcitation during maximum voluntary apnea in young swimmers, which could activate the spleen (which is a reservoir organ for oxygenated blood). Therefore, it is possible that the chemoreflex, autonomic function, and storage/delivery oxygen organ(s) are linked to apnea in immersion water sports. In this review, we summarized the available evidence related to chemoreflex control in immersion water sports. Subsequently, we propose a possible physiological mechanistic model that could contribute to providing new avenues for understanding the respiratory physiology of water sports.
RESUMEN
PURPOSE: Cancer is the leading cause of death among Hispanics/Latinos in the USA. Latina cancer survivors experience higher symptom burden than other cancer survivors. A healthy lifestyle can decrease recurrent cancer risk, increase well-being, and may decrease symptom burden in cancer survivors. The purpose of this study was to explore the barriers and facilitators for adopting healthy lifestyle behaviors among Latina cancer survivors. METHODS: Using the Health Belief Model as the theoretical framework, qualitative descriptive methodology was used for secondary analysis of data from a previously conducted randomized clinical trial. Transcripts from the telephone health coaching calls, analyzed in the original language (English or Spanish), were used for this qualitative analysis. RESULTS: Intervention telephone call transcript data from Latina cancer survivors (n = 14) were analyzed. Major themes were as follows: Perceived susceptibility to other chronic illnesses, perceived benefits of a healthy lifestyle, and perceived barriers and facilitators of adopting a healthy lifestyle. Lack of knowledge about healthy lifestyle behaviors could prevent participants from adopting a healthy lifestyle; gaining new knowledge about healthy lifestyle behaviors was a facilitator for changing lifestyle. Family responsibility and wearable technology could both prevent and motivate the participants to adopt a healthy lifestyle. CONCLUSION: Developing culturally appropriate interventions for Latina cancer survivors is vital to decrease symptom burden and health risks, as well as improve health outcomes in this population.
Asunto(s)
Supervivientes de Cáncer , Estilo de Vida Saludable , Hispánicos o Latinos , Humanos , Recurrencia Local de Neoplasia , Investigación CualitativaRESUMEN
BACKGROUND: Diabetes mellitus (DM) has glucose variability that is of such relevance that the appearance of vascular complications in patients with DM has been attributed to hyperglycemic and dysglycemic events. It is known that T1D patients mainly have glycemic variability with a specific oscillatory pattern with specific circadian characteristics for each patient. However, it has not yet been determined whether an oscillation pattern represents the variability of glycemic in T2D. This is why our objective is to determine the characteristics of glycemic oscillations in T2D and generate a robust predictive model. RESULTS: Showed that glycosylated hemoglobin, glycemia, and body mass index were all higher in patients with T2D than in controls (all p < 0.05). In addition, time in hyperglycemia and euglycemia was markedly higher and lower in the T2D group (p < 0.05), without significant differences for time in hypoglycemia. Standard deviation, coefficient of variation, and total power of glycemia were significantly higher in the T2D group than Control group (all p < 0.05). The oscillatory patterns were significantly different between groups (p = 0.032): the control group was mainly distributed at 2-3 and 6 days, whereas the T2D group showed a more homogeneous distribution across 2-3-to-6 days. CONCLUSIONS: The predictive model of glycemia showed that it is possible to accurately predict hyper- and hypo-glycemia events. Thus, T2D patients exhibit specific oscillatory patterns of glycemic control, which are possible to predict. These findings may help to improve the treatment of DM by considering the individual oscillatory patterns of patients.
Asunto(s)
Humanos , Diabetes Mellitus Tipo 2/complicaciones , Hipoglucemia , Glucemia , GlucosaRESUMEN
During an apnea, changes in PaO2 activate peripheral chemoreceptors to increase respiratory drive. Athletes with continuous apnea, such as breath-hold divers, have shown a decrease in hypoxic ventilatory response (HVR), which could explain the long apnea times; however, this has not been studied in swimmers. We hypothesize that the long periods of voluntary apnea in swimmers is related to a decreased HVR. Therefore, we sought to determine the HVR and cardiovascular adjustments during a maximum voluntary apnea in young-trained swimmers. In fifteen trained swimmers and twenty-seven controls we studied minute ventilation (V E ), arterial saturation (SpO2), heart rate (HR), and autonomic response [through heart rate variability (HRV) analysis], during acute chemoreflex activation (five inhalations of pure N2) and maximum voluntary apnea test. In apnea tests, the maximum voluntary apnea time and the end-apnea HR were higher in swimmers than in controls (p < 0.05), as well as a higher low frequency component of HRV (p < 0.05), than controls. Swimmers showed lower HVR than controls (p < 0.01) without differences in cardiac hypoxic response (CHR). We conclude that swimmers had a reduced HVR response and greater maximal voluntary apnea duration, probably due to decreased HVR.
RESUMEN
Daily glucose variability is higher in diabetic mellitus (DM) patients which has been related to the severity of the disease. However, it is unclear whether glycemic variability displays a specific pattern oscillation or if it is completely random. Thus, to determine glycemic variability pattern, we measured and analyzed continuous glucose monitoring (CGM) data, in control subjects and patients with DM type-1 (T1D). CGM data was assessed for 6 days (day: 08:00-20:00-h; and night: 20:00-08:00-h). Participants (n = 172; age = 18-80 years) were assigned to T1D (n = 144, females = 65) and Control (i.e., healthy; n = 28, females = 22) groups. Anthropometry, pharmacologic treatments, glycosylated hemoglobin (HbA1c) and years of evolution were determined. T1D females displayed a higher glycemia at 10:00-14:00-h vs. T1D males and Control females. DM patients displays mainly stationary oscillations (deterministic), with circadian rhythm characteristics. The glycemia oscillated between 2 and 6 days. The predictive model of glycemia showed that it is possible to predict hyper and hypoglycemia (R2 = 0.94 and 0.98, respectively) in DM patients independent of their etiology. Our data showed that glycemic variability had a specific oscillation pattern with circadian characteristics, with episodes of hypoglycemia and hyperglycemia at day phases, which could help therapeutic action for this population.
Asunto(s)
Diabetes Mellitus Tipo 1/sangre , Control Glucémico , Adulto , Glucemia/metabolismo , Estudios de Casos y Controles , Ritmo Circadiano , Femenino , Hemoglobina Glucada/metabolismo , Humanos , Hiperglucemia/sangre , Hipoglucemia/sangre , Masculino , Persona de Mediana Edad , Modelos BiológicosRESUMEN
BACKGROUND: The replacement of traditional in vivo bioequivalence studies by in vitro dissolution assays, based on the biopharmaceutical classification system (BCS), has emerged as an important tool for demonstrating the interchangeability of multisource products. This paper summarizes the current implementation of the BCS-based biowaiver for the development of multisource products in Latin America, and identifies several challenges and opportunities for greater convergence and application of BCS regulatory requirements. METHODS: Differences and similarities between the current BCS-based biowaivers' guidelines proposed by two relevant regulatory agencies for the Latin American region (FDA and WHO) and the new ICH harmonization guideline were identified and compared. An update of the BCS-based biowaiver guideline for Latin American countries was also considered, based on the respective regulatory information on bioequivalence studies, which is publicly available. RESULTS: About 50% of the Latin American countries analyzed have no information on the implementation of any bioequivalence standards, while in the countries where bioequivalence studies are considered, the acceptance and application of BCS-based biowaiver requirements is quite heterogeneous. This situation contrasts with the international trend of global harmonization for BCS-based biowaiver guidance, suggesting the need in Latin America to identify opportunities and overcome challenges to improve the development of BCS-based biowaivers to avoid costly and time-consuming in vivo bioequivalence studies. CONCLUSIONS: The study shows that the region is in a position to improve access to safe and effective medicines at a reasonable cost by applying BCS-based biowaiver guidance.
Asunto(s)
Biofarmacia , Preparaciones Farmacéuticas , América Latina , Políticas , Equivalencia TerapéuticaRESUMEN
PURPOSE: Assess feasibility, acceptability, and preliminary efficacy of an integrated symptom management and lifestyle intervention (SMLI) to improve adherence to the American Cancer Society's (ACS) Guidelines on Nutrition and Physical Activity in Latina cancer survivors and their informal caregivers (dyads). METHODS: Forty-five dyads were randomized to a 12-week telephone-delivered intervention or attention control. Intervention effects on nutrition, physical activity, symptom burden, and self-efficacy for symptom management were estimated using Cohen's ds. RESULTS: Mean age was 64 for survivors and 53 for caregivers. Feasibility was demonstrated by the 63% consent rate out of approached dyads. The SMLI was acceptable for 98% of dyads. Among survivors, medium-to-large effect sizes were found for increased servings of total fruits and vegetables (d = 0.55), vegetables (d = 0.72), and decreased sugar intake (d = - 0.51) and medium clinically significant effect sizes for total minutes of physical activity per week (d = 0.42) and grams of fiber intake per day (d = 0.40) for intervention versus attention control. Additionally, medium-to-large intervention effects were found for the reduction of symptom burden (d = 0.74). For caregivers, medium-to-large intervention effects were found for reduced total sugar intake (d = - 0.60) and sugar intake from sugar-sweetened beverages (d = - 0.65); vegetable intake was increased with a medium effect size (d = 0.41). CONCLUSION: SMLI was feasible and acceptable for both dyadic members. A larger, well-powered trial is needed to formally evaluate SMLI effectiveness. IMPLICATIONS FOR CANCER SURVIVORS: Integrating symptom management with lifestyle behavior interventions may increase adherence to the ACS guidelines on nutrition and physical activity to prevent new and recurrent cancers.
Asunto(s)
Supervivientes de Cáncer , Neoplasias , Cuidadores , Dieta , Hispánicos o Latinos , Humanos , Estilo de Vida , Persona de Mediana Edad , Neoplasias/terapia , Proyectos PilotoRESUMEN
Baroreflex (BR) control is critically dependent of sympathetic and parasympathetic modulation. It has been documented that during acute hypobaric hypoxia there is a BR control impairment, however, the effect of a natural hypoxic environment on BR function is limited and controversial. Therefore, the aim of this study was to determine the effect of acute High-Altitude exposure on sympathetic/parasympathetic modulation of BR control in normal rats. Male Sprague Dawley rats were randomly allocated into Sea-Level (n = 7) and High-Altitude (n = 5) (3,270 m above sea level) groups. The BR control was studied using phenylephrine (Phe) and sodium nitroprusside (SNP) through sigmoidal analysis. The autonomic control of the heart was estimated using heart rate variability (HRV) analysis in frequency domain. Additionally, to determine the maximum sympathetic and parasympathetic activation of BR, spectral non-stationary method analysis, during Phe (0.05 µg/mL) and SNP administration (0.10 µg/mL) were used. Compared to Sea-Level condition, the High-Altitude group displayed parasympathetic withdrawal (high frequency, 0.6-2.4 Hz) and sympathoexcitation (low frequency, 0.04-0.6 Hz). Regarding to BR modulation, rats showed a significant decrease (p < 0.05) of curvature and parasympathetic bradycardic responses to Phe, without significant differences in sympathetic tachycardic responses to SNP after High-Altitude exposure. In addition, the non-stationary analysis of HRV showed a reduction of parasympathetic activation (Phe) in the High-Altitude group. Our results suggest that acute exposure to High-Altitude produces an autonomic and BR control impairment, characterized by parasympathetic withdrawal after 24 h of high-altitude exposure.
RESUMEN
The aim of this study was to determine the acute effects of high-intensity interval training (HIIT) exercise and endurance exercise (EE) on pulmonary function, sympathetic/parasympathetic balance, and cardiorespiratory coupling (CRC) in healthy participants. Using a crossover repeated-measurements design, four females and four males were exposed to EE (20 min at 80% maximal heart rate [HR]), HIIT (1 min of exercise at 90% maximal HR per 1 min of rest, 10 times), or control condition (resting). Pulmonary function, HR, CRC, and heart rate variability (HRV) were assessed before and after the interventions. Results revealed no significant effects of EE or HIIT on pulmonary function. The EE, but not HIIT, significantly increased CRC. In contrast, HRV was markedly changed by HIIT, not by EE. Indeed, both the low-frequency (LFHRV ) and high-frequency (HFHRV ) components of HRV were increased and decreased, respectively, after HIIT. The increase in LFHRV was greater after HIIT than after EE. Therefore, a single bout of HIIT or EE has no effects on pulmonary function. Moreover, CRC and cardiac autonomic regulation are targeted differently by the two exercise modalities.
Asunto(s)
Entrenamiento Aeróbico/métodos , Frecuencia Cardíaca , Entrenamiento de Intervalos de Alta Intensidad/métodos , Respiración , Adulto , Presión Sanguínea , Entrenamiento Aeróbico/efectos adversos , Femenino , Entrenamiento de Intervalos de Alta Intensidad/efectos adversos , Humanos , MasculinoRESUMEN
Enhanced central chemoreflex (CC) gain is observed in volume overload heart failure (HF) and is correlated with autonomic dysfunction and breathing disorders. The aim of this study was to determine the role of the CC in the development of respiratory and autonomic dysfunction in HF. Volume overload was surgically created to induce HF in male Sprague-Dawley rats. Radiotelemetry transmitters were implanted for continuous monitoring of blood pressure and heart rate. After recovering from surgery, conscious unrestrained rats were exposed to episodic hypercapnic stimulation [EHS; 10 cycles/5 min, inspiratory fraction of carbon dioxide (FICO2) 7%] in a whole body plethysmograph for recording of cardiorespiratory function. To determine the contribution of CC to cardiorespiratory variables, selective ablation of chemoreceptor neurons within the retrotrapezoid nucleus (RTN) was performed via injection of saporin toxin conjugated to substance P (SSP-SAP). Vehicle-treated rats (HF+Veh and Sham+Veh) were used as controls for SSP-SAP experiments. Sixty minutes post-EHS, minute ventilation was depressed in sham animals relative to HF animals (ΔVÌe: -5.55 ± 2.10 vs. 1.24 ± 1.35 mL/min 100 g, P < 0.05; Sham+Veh vs. HF+Veh). Furthermore, EHS resulted in autonomic imbalance, cardiorespiratory entrainment, and ventilatory disturbances in HF+Veh but not Sham+Veh rats, and these effects were significantly attenuated by SSP-SAP treatment. Also, the apnea-hypopnea index (AHI) was significantly lower in HF+SSP-SAP rats compared with HF+Veh rats (AHI: 5.5 ± 0.8 vs. 14.4 ± 1.3 events/h, HF+SSP-SAP vs. HF+Veh, respectively, P < 0.05). Finally, EHS-induced respiratory-cardiovascular coupling in HF rats depends on RTN chemoreceptor neurons because it was reduced by SSP-SAP treatment. Overall, EHS triggers ventilatory plasticity and elicits cardiorespiratory abnormalities in HF that are largely dependent on RTN chemoreceptor neurons.
Asunto(s)
Enfermedades del Sistema Nervioso Autónomo/fisiopatología , Sistema Nervioso Central/fisiopatología , Células Quimiorreceptoras/metabolismo , Insuficiencia Cardíaca/fisiopatología , Neuronas/fisiología , Trastornos Respiratorios/fisiopatología , Animales , Enfermedades del Sistema Nervioso Autónomo/metabolismo , Presión Sanguínea/fisiología , Sistema Nervioso Central/metabolismo , Insuficiencia Cardíaca/metabolismo , Frecuencia Cardíaca/fisiología , Hipercapnia/metabolismo , Hipercapnia/fisiopatología , Masculino , Neuronas/metabolismo , Ratas , Ratas Sprague-Dawley , Respiración , Trastornos Respiratorios/metabolismoRESUMEN
Age represents the highest risk factor for death due to cardiovascular disease. Heart failure (HF) is the most common cardiovascular disease in elder population and it is associated with cognitive impairment (CI), diminishing learning and memory process affecting life quality and mortality in these patients. In HF, CI has been associated with inadequate O2 supply to the brain; however, an important subset of HF patients displays CI with almost no alteration in cerebral blood flow. Importantly, nothing is known about the pathophysiological mechanisms underpinning CI in HF with no change in brain tissue perfusion. Here, we aimed to study memory performance and learning function in a rodent model of HF that shows no change in blood flow going to the brain. We found that HF rats presented learning impairments and memory loss. In addition, HF rats displayed a decreased level of Wnt/ß-catenin signaling downstream elements in the hippocampus, one pathway implicated largely in aging diseases. Taken together, our results suggest that in HF rats CI is associated with dysfunction of the Wnt/ß-catenin signaling pathway. The mechanisms involved in the alterations of Wnt/ß-catenin signaling in HF and its contribution to the development/maintenance of CI deserves future investigations.
Asunto(s)
Disfunción Cognitiva/metabolismo , Insuficiencia Cardíaca/metabolismo , Hipocampo/metabolismo , Vía de Señalización Wnt/fisiología , Animales , Disfunción Cognitiva/etiología , Modelos Animales de Enfermedad , Insuficiencia Cardíaca/complicaciones , Aprendizaje por Laberinto/fisiología , Ratas , Memoria Espacial/fisiología , beta Catenina/metabolismoRESUMEN
BACKGROUND: Hypertonia is characterized by increased resting muscle tone. Previous studies have shown that adult patients with hypertonia displayed autonomic imbalance. However, cardiac sympatho-vagal control in infants with hypertonia have not been explored. The main aim was to estimate cardiac autonomic control in infants with hypertonia using heart rate variability (HRV). METHODS: Thirty infants (0-2 years old) were studied. Heart rate (HR) and R-R interval time series were obtained in 15 Control and 15 Hypertonia infants. HRV was analyzed in time and frequency domains. Additionally, non-linear analysis and entropy measurements were performed. RESULTS: Infants with hypertonia showed cardiac autonomic imbalance as evidenced by alterations in HRV, characterized by an increased power spectral density of low frequency (LF) over high frequency (HF) components of HRV. Indeed, a â¼7% increase in LF, and â¼30% reduction in HF, were found in infants with hypertonia vs. control infants. In addition, time domain and non-linear HRV analysis (Root-mean-square of successive normal sinus R-R interval difference, entropy, and R-R interval variability) were all significantly decreased in hypertonia vs. control subjects. CONCLUSIONS: Our results showed that hypertonia infants displayed HRV disturbances, which suggest an alteration in overall autonomic cardiac modulation in infants with hypertonia compared with healthy condition.
Asunto(s)
Sistema Nervioso Autónomo/fisiopatología , Frecuencia Cardíaca , Hipertonía Muscular/fisiopatología , Factores de Edad , Preescolar , Estudios Transversales , Electrocardiografía , Entropía , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Monitoreo Ambulatorio , Dinámicas no Lineales , Estudios Prospectivos , Nervio Vago/fisiologíaRESUMEN
Activation of the sympathetic nervous system is a hallmark of heart failure (HF) and is positively correlated with disease progression. Catecholaminergic (C1) neurons located in the rostral ventrolateral medulla (RVLM) are known to modulate sympathetic outflow and are hyperactivated in volume overload HF. However, there is no conclusive evidence showing a contribution of RVLM-C1 neurons to the development of cardiac dysfunction in the setting of HF. Therefore, the aim of this study was to determine the role of RVLM-C1 neurons in cardiac autonomic control and deterioration of cardiac function in HF rats. A surgical arteriovenous shunt was created in adult male Sprague-Dawley rats to induce HF. RVLM-C1 neurons were selectively ablated using cell-specific immunotoxin (dopamine-ß hydroxylase saporin [DßH-SAP]) and measures of cardiac autonomic tone, function, and arrhythmia incidence were evaluated. Cardiac autonomic imbalance, arrhythmogenesis and cardiac dysfunction were present in HF rats and improved after DßH-SAP toxin treatment. Most importantly, the progressive decline in fractional shortening observed in HF rats was reduced by DßH-SAP toxin. Our results unveil a pivotal role played by RVLM-C1 neurons in cardiac autonomic imbalance, arrhythmogenesis and cardiac dysfunction in volume overload-induced HF.
Asunto(s)
Tronco Encefálico/citología , Insuficiencia Cardíaca/fisiopatología , Corazón/fisiología , Neuronas/fisiología , Animales , Sistema Nervioso Autónomo/fisiopatología , Tronco Encefálico/fisiopatología , Humanos , Masculino , Bulbo Raquídeo/citología , Ratas , Ratas Sprague-Dawley , Sistema Nervioso Simpático/fisiopatologíaRESUMEN
The carotid body (CB) is the main arterial chemoreceptor involved in oxygen sensing. Upon hypoxic stimulation, CB chemoreceptor cells release neurotransmitters, which increase the frequency of action potentials in sensory nerve fibers of the carotid sinus nerve. The identity of the molecular entity responsible for oxygen sensing is still a matter of debate; however several ion channels have been shown to be involved in this process. Connexin-based ion channels are expressed in the CB; however a definitive role for these channels in mediating CB oxygen sensitivity has not been established. To address the role of these channels, we studied the effect of blockers of connexin-based ion channels on oxygen sensitivity of the CB. A connexin43 (Cx43) hemichannel blocking agent (CHBa) was applied topically to the CB and the CB-mediated hypoxic ventilatory response (FiO2 21, 15, 10 and 5%) was measured in adult male Sprague-Dawley rats (~250 g). In normoxic conditions, CHBa had no effect on tidal volume or respiratory rate, however Cx43 hemichannels inhibition by CHBa significantly impaired the CB-mediated chemoreflex response to hypoxia. CHBa reduced both the gain of the hypoxic ventilatory response (HVR) and the maximum HVR by ~25% and ~50%, respectively. Our results suggest that connexin43 hemichannels contribute to the CB chemoreflex response to hypoxia in rats. Our results suggest that CB connexin43 hemichannels may be pharmacological targets in disease conditions characterized by CB hyperactivity.