Arterial Baroreflex Sensitivity Research Articles

Parental fructose consumption induces early baroreflex dysfunction in offspring: impact on arterial pressure and on insulin resistance.

Fructose overconsumption is a worldwide trend, and it has been found to cause metabolic disorders in parents and their offspring. Additionally, metabolic syndrome has been closely associated with increased cardiovascular risk. In this study, we hypothesized that the chronic fructose consumption by parents could trigger autonomic dysfunction and cardiometabolic disorders in their offspring. Wistar rats undergo an intake of 10% of fructose in drinking water or regular water for 60 days before mating. Their offspring, control (C) and fructose (F) groups, were evaluated 30 days after weaning. Lower birth weight, increased levels of blood triglycerides and insulin resistance were observed in F compared to C group. The offspring of the fructose parents showed increased mean arterial pressure (C: 104 ± 1 vs. F: 111 ± 2 mmHg) and baroreflex sensitivity impairment, characterized by reduced bradycardic (C: -1.6 ± 0.06 vs. F: -1.3 ± 0.06 bpm/mmHg) and tachycardic responses (C: -4.0 ± 0.1 vs. F: -3.1 ± 0.2 bpm/mmHg). Finally, a higher baroreflex-induced tachycardia was associated with lower insulin tolerance (r = -0.55, P < 0.03) and higher systolic arterial pressure (r = 0.54, P < 0.02). In conclusion, our findings indicate that the excessive consumption of fructose by parents is associated with early autonomic, cardiovascular, and metabolic derangement in the offspring, favoring an increased cardiometabolic risk when they reach adulthood.

Cardiorespiratory dynamics during respiratory maneuver in athletes.

Introduction: The modern practice of sports medicine and medical rehabilitation requires the search for subtle criteria for the development of conditions and recovery of the body after diseases, which would have a prognostic value for the prevention of negative effects of training and rehabilitation tools, and also testify to the development and course of mechanisms for counteracting pathogenetic processes in the body. The purpose of this study was to determine the informative directions of the cardiorespiratory system parameters dynamics during the performing a maneuver with a change in breathing rate, which may indicate the body functional state violation. Methods: The results of the study of 183 healthy men aged 21.2 ± 2.3 years who regularly engaged in various sports were analyzed. The procedure for studying the cardiorespiratory system included conducting combined measurements of indicators of activity of the respiratory and cardiovascular systems in a sitting position using a spiroarteriocardiograph device. The duration of the study was 6min and involved the sequential registration of three measurements with a change in breathing rate (spontaneous breathing, breathing at 0.1 Hz and 0.25Hz). Results: Performing a breathing maneuver at breathing 0.1Hz and breathing 0.25Hz in comparison with spontaneous breathing leads to multidirectional significant changes in heart rate variability indicators-TP (ms2), LF (ms2), LFHF (ms2/ms2); of blood pressure variability indicators-TPDBP (mmHg2), LFSBP (mmHg2), LFDBP (mmHg2), HFSBP (mmHg2); of volume respiration variability indicators - LFR, (L×min-1)2; HFR, (L×min-1)2; LFHFR, (L×min-1)2/(L×min-1)2; of arterial baroreflex sensitivity indicators - BRLF (ms×mmHg-1), BRHF (ms×mmHg-1). Differences in indicators of systemic hemodynamics and indicators of cardiovascular and respiratory systems synchronization were also informative. Conclusion: According to the results of the study, it is shown that during performing a breathing maneuver with a change in the rate of breathing, there are significant changes in cardiorespiratory parameters, the analysis of which the increments made it possible to determine of the changes directions dynamics, their absolute values and informative limits regarding the possible occurrence of the cardiorespiratory interactions dysregulation.

Sex differences in Black Veterans with PTSD: women versus men have higher sympathetic activity, inflammation, and blunted cardiovagal baroreflex sensitivity.

Post-traumatic stress disorder (PTSD) is associated with greater risk of incident hypertension and cardiovascular disease (CVD). Inflammation and autonomic derangements are suggested as contributing mechanisms. Women and Black adults have higher CVD risk associated with stress; however, whether there is a sex difference in autonomic and inflammatory mechanisms among Black individuals with PTSD is not known. We hypothesized that Black women with PTSD have higher inflammation, sympathetic nervous system (SNS) activity and impaired baroreflex sensitivity (BRS). In 42 Black Veterans with PTSD (Women, N = 18 and Men, N = 24), we measured inflammatory biomarkers, continuous blood pressure (BP), heart rate (HR) and muscle sympathetic nerve activity (MSNA) at rest and during arterial BRS testing via the modified Oxford technique. Groups were matched for age and body mass index (BMI). Resting BP was similar between groups, but HR was higher (76 ± 12 vs. 68 ± 9 beats/min, p = 0.021) in women compared to men. Although women had lower PTSD symptoms severity (57 ± 17 vs. 68 ± 12 a.u.), resting MSNA (27 ± 13 vs. 16 ± 5 bursts/min, p = 0.003) was higher in women compared to men, respectively. Likewise, cardiovagal BRS was blunted (p = 0.002) in women (7.6 ± 4.3ms/mmHg) compared to men (15.5 ± 8.4ms/mmHg) while sympathetic BRS was not different between groups (p = 0.381). Black women also had higher (p = 0.020) plasma levels of interleukin-2 (IL-2). Black women with PTSD have higher resting HR and MSNA, greater impairment of cardiovagal BRS and possibly higher inflammation. These findings suggest a higher burden of autonomic and inflammatory derangements in Black women compared to Black men with PTSD.

Reflex regulation and the functional assessment possibility of the cardiorespiratory system in pregnancy: a systematic review

INTRODUCTION: Anesthesia planning for cesarean section requires knowledge of physiological and functional features a pregnant patient has in her gestational age. Proper planning reduced the perioperative critical incidents risk. OBJECTIVE: Search for data on the methods and results of assessing the cardiorespiratory status of pregnant women using methods that involve such key mechanisms of arterial baroreflex (ABR) and peripheral chemoreflex (PCR) mechanisms. MATERIAL AND METHODS: We performed a systematic review of the literature in accordance with the PRISMA guidelines. The bibliographic search was performed in December 2022 in the Medline (Pubmed), RSCI (eLibrary.ru) and Cochrane Library databases. The search keywords were: “pregnancy breath holding test”, “pregnancy chemoreflex”, “pregnancy baroreflex”, “Valsalva test pregnancy”. RESULTS: 110 documents were found, after deleting 68 papers for various reasons 42 full-text sources were analyzed, including a detailed comparative analysis of 8 sources that met totally the inclusion criteria. The design, objectives, methods, data availability, and outcomes of the studies were heterogeneous, so a meta-analysis was not performed. Were extracted and summarized data on functional changes in the work of cardiorespiratory system during pregnancy and changes in the sensitivity of the baroreflex and chemoreflex. CONCLUSIONS: The sensitivity of PCR in pregnant women can be assessed by inhalation of hyperoxic, hypercapnic and isooxic-hypercapnic gas mixtures (rebreathing test). The sensitivity of ABR in pregnant can be assessed by phenylephrine test, Valsalva test, orthostatic test, and spectral analysis of the sequences of blood pressure values and the R-R interval. The sensitivity of PCR in full-term pregnancy increases. The sensitivity of ABR in pregnant progressively decreases from the beginning of pregnancy to the end of the second trimester and increases in the postpartum period to initial level; in the third trimester of pregnancy, changes in ABR sensitivity are individual and do not have a single trend.

In vivo molecular imaging of cardiac angiogenesis in persons with and without type 2 diabetes: A cross-sectional 68 Ga-RGD-PET study.

To assess cardiac angiogenesis in type 2 diabetes by positron emission tomography (PET) tracer [68 Ga]Ga-NODAGA-E[(cRGDyK)]2 (68 Ga-RGD) imaging. Cross-sectional study including 20 persons with type 2 diabetes and 10 non-diabetic controls (CONs). Primary prespecified outcome was difference in cardiac angiogenesis (cardiac 68 Ga-RGD mean target-to-background ratio [TBRmean ]) between type 2 diabetes and CONs. Secondary outcome was to investigate associations between cardiac angiogenesis and kidney function and other risk factors. Participants with type 2 diabetes had a mean ± SD age of 61 ± 9 years, 30% were women, median (IQR) diabetes duration of 11 (6-19) years and 3 (15%) had a history of cardiovascular disease. The CONs had comparable age and sex distribution to the participants with type 2 diabetes, and none had a history of coronary artery disease. Myocardial flow reserve was lower in type 2 diabetes (2.7 ± 0.6) compared with CONs (3.4 ± 1.2) ( p =0.03) and coronary artery calcium score was higher (562 [142-905] vs. 1 [0-150] p =0.04). Cardiac 68 Ga-RGD TBRmean was similar in participants with type 2 diabetes (0.89 ± 0.09) and CONs (0.89 ± 0.10) ( p =0.92). Cardiac 68 Ga-RGD TBRmean was not associated with estimated glomerular filtration rate, urine albumin creatinine ratio, cardiovascular disease, coronary artery calcium score or baroreflex sensitivity, neither in pooled analyses nor in type 2 diabetes. Cardiac angiogenesis, evaluated with 68 Ga-RGD PET, was similar in type 2 diabetes and CONs. Cardiac angiogenesis was not associated with kidney function or other risk markers in pooled analyses or in analyses restricted to type 2 diabetes.

Carotid Baroreceptor Magnetic Activation and Beat-to-Beat Blood Pressure Variability, Implications to Treat Abrupt Blood Pressure Elevation in Labile Hypertension.

Mounting evidence suggests enhanced blood pressure (BP) variability (BPV) independent role in cardiovascular (CV) damage. The goal was to estimate the effect of the carotid baroreceptor (CB) magnetic stimulation on sudden high BP elevation. Mean femoral arterial BP (MAP), heart rate (HR), baroreflex sensitivity (BRS), and ear lobe skin microcirculatory blood flow, by microphotoelectric plethysmography (MPPG), were simultaneously recorded in conscious rabbits sedated by pentobarbital intravenous (i.v.) infusion (5 mg/kg/h) after 40 min CB exposure to 350 mT static magnetic field (SMF), by Nd2 -Fe14 -B magnets (n = 14), or sham magnets exposure (n = 14). BRS was assessed from HR and MAP responses to abrupt hypotension induced by i.v. bolus injections of nitroprusside (Ni) and abrupt MAP elevation (MAPAE ) by i.v. bolus of phenylephrine (Ph). Beat-to-beat BPV was estimated by MAP standard deviation. SMF CB exposure significantly increased BRSNi (74.5 ± 17.8%, P < 0.001) and microcirculation (23.8% ± 11.0%, P = 0.039); decreased MAP (-5.7 ± 1.7%, P < 0.014) and phenylephrine-induced MAPAE (-19.1%, P = 0.043). MAPAE positively correlated with resting MAP (r = 0.342, P = 0.0383) and MAP SD (r = 0.383, P = 0.0194), and inversely with BRSPh (r = -0.47, P = 0.0156). SMF CB exposure enhanced the nitroprusside, which acts by releasing nitric oxide (NO), vasodilatory effect. This indicates arterial baroreflex to improve vessel sensitivity to NO, which is a new physiology with BP buffering effect. A positive correlation of MAP SD to phenylephrine BP ramps suggests a causal relationship and BPV prognostic significance to forecast abrupt BP elevation. Mechano/baroreceptor magneto-sensing property proposed to be the basic physiology by which SMFs boost CV autonomic regulation with potential implementation in high CV risk labile arterial hypertensive disease. © 2022 Bioelectromagnetics Society.

Strong evidence for parasympathetic sinoatrial reinnervation after heart transplantation.

Heart transplantation (HTx) surgically denervates the heart. We examined indices of sinoatrial reinnervation, with emphasis on (1) the occurrence and timing of parasympathetic reinnervation, and (2) the consequences of reinnervation for heart rate (HR) responsiveness and arterial baroreceptor sensitivity. Fifty HTx recipients were prospectively followed for 36 months after surgery. Hemodynamic variables and heart rate variability were continuously recorded at supine rest, 60 degrees head-up-tilt, during the Valsalva maneuver and during handgrip isometric exercise. Suggesting parasympathetic reinnervation: at baseline rest, root of the mean squared differences of successive RR intervals increased from median 3.9(5.9) to 7.1(5.1) ms (p < 0.001); high-frequency power increased from 4.0(12) to 5.7(18.9) ms2 (p=0.018); and baroreceptor sensitivity increased from 0.04(0.36) to 1.3(2.4) ms/mmHg (p < 0.001). Suggesting sympathetic reinnervation: at baseline rest low-frequency power increased from 0.49(2.5) to 7.5(18.1) ms2 (p < 0.001); and HR responses to sympathetic stimulation during (1) head-up tilt increased from 1.9(4.2) to 9.1(8.2) bpm (p < 0.001), (2) Valsalva increased from 1.6(1.4) to 8.3(10.8) bpm (p < 0.001) and (3) handgrip increased from 0.3(0.6) to 1.9(5.1) bpm (p < 0.001). Signs of sympathetic reinnervation emerged within 6 months, while signs of parasympathetic reinnervation emerged by 24 months. Root of the mean squared differences of successive RR intervals, high-frequency and low-frequency variability, HR responsiveness and arterial baroreflex sensitivity all increased after HTx, suggesting functional parasympathetic and sympathetic sinoatrial reinnervation. Accordingly, the pathological regulatory state present in heart transplant recipients, which is responsible for a host of functional and clinical abnormalities, is being partially offset over time by restored autonomic control of the heart in many heart transplant recipients.

Advanced Cross-Correlation Function Application to Identify Arterial Baroreflex Sensitivity Variations From Healthy to Diabetes Mellitus

Diabetes mellitus (DM) is a chronic disease characterized by elevated blood glucose levels, which leads over time to serious damage to the heart, blood vessels, eyes, kidneys, and nerves. DM is of two types–types 1 or 2. In type 1, there is a problem with insulin secretion, and in type 2–insulin resistance. About 463 million people worldwide have diabetes, and 80% of the majority live in low- and middle-income countries, and 1.5 million deaths are directly attributed to diabetes each year. Autonomic neuropathy (AN) is one of the common diabetic complications, leading to failure in blood pressure (BP) control and causing cardiovascular disease. Therefore, early detection of AN becomes crucial to optimize treatment. We propose an advanced cross-correlation function (ACCF) between BP and heart rate with suitable threshold parameters to analyze and detect early changes in baroreflex sensitivity (BRS) in DM with AN (DM+). We studied heart rate (HR) and systolic BP responses during tilt in 16 patients with diabetes mellitus only (DM−), 19 diabetes mellitus with autonomic dysfunction (DM+), and 10 healthy subjects. The ACCF analysis revealed that the healthy and DM groups had different filtered percentages of significant maximum cross-correlation function (CCF) value (p < 0.05), and the maximum CCF value after thresholds was significantly reduced during tilt in the DM+ group (p < 0.05). The maximum CCF index, a parameter for the phase between HR and BP, separated the healthy group from the DM groups (p < 0.05). Due to the maximum CCF index in DM groups being located in the positive range and significantly different from healthy ones, it could be speculated that BRS dysfunction in DM and AN could cause a phase change from lead to lag. ACCF could detect and separate DM+ from DM groups. This fact could represent an advantage of the ACCF algorithm. A common cross-correlation analysis was not easy to distinguish between DM− and DM+. This pilot study demonstrates that ACCF analysis with suitable threshold parameters could explore hidden changes in baroreflex control in DM+ and DM−. Furthermore, the superiority of this ACCF algorithm is useful in distinguishing whether AN is present or not in DM.

Central modulation of cardiac baroreflex moment-to-moment sensitivity during treadmill exercise in conscious cats.

It remains undetermined whether the cardiac component of the entire arterial baroreflex is blunted even at the onset of low‐intensity exercise. We sought to examine the moment‐to‐moment sensitivity of the cardiac baroreflex during walking at different speeds and the presumed mechanisms responsible for baroreflex modulation in conscious cats. Arterial baroreflex sensitivity for heart rate was estimated from the baroreflex ratio between changes in systolic arterial blood pressure and heart rate and from the slope of the baroreflex curve between the cardiovascular responses to brief occlusion of the abdominal aorta. Treadmill walking was performed for 1 min at three levels of speed (low: 20–30 m/min, moderate: 40 m/min, and high: 50–60 m/min) or for 3 min at the stepwise change of speed (low to high to low transition). Cardiac baroreflex sensitivity was blunted at the onset of walking, irrespective of speed. Thereafter, the blunted cardiac baroreflex sensitivity was restored around 15 s of walking at any speed, while the blunting occurred again at 45 s of high‐speed walking. The inhibition of cardiac baroreflex sensitivity also occurred (1) during the speed transition from low to high and (2) at 45 s of high‐speed exercise of the stepwise exercise. The blunted cardiac baroreflex sensitivity was restored immediately to the resting level during the speed transition from high to low, despite sustained pressor and tachycardiac responses. Therefore, moment‐to‐moment modulation of the cardiac baroreflex during exercise would occur in association with motor intention (i.e., exercise onset) and effort (i.e., treadmill speed).

Increased Muscle Sympathetic Nerve Activity with Acute Hyperinsulinemia: Role of Insulin‐stimulated Peripheral Vasodilation and the Response of the Arterial Baroreflex

ObjectiveHyperinsulinemia elicits an increase sympathetic nervous system activity directed toward skeletal muscle (muscle sympathetic nerve activity, MSNA). The insulin‐mediated increase in MSNA is primarily attributed to its effect within the central nervous system. In addition to direct central effects, insulin also elicits peripheral vasodilation, which may further increase MSNA via arterial baroreflex‐mediated mechanisms in order to maintain blood pressure (BP). Herein we examined the contribution of insulin‐induced peripheral vasodilation and role for the arterial baroreflex in the MSNA response to hyperinsulinemia. We hypothesized that rescuing peripheral resistance with co‐infusion of the vasoconstrictor phenylephrine would attenuate the MSNA response to hyperinsulinemia. We further hypothesized the insulin‐mediated increase in MSNA would be recapitulated with another vasodilator (sodium nitroprusside, SNP).MethodsIn 33 healthy adults (28M/5F, 28±1 yrs, BMI 25.0±0.5 kg/m2) MSNA (microneurography) and BP (Finometer/brachial catheter) were measured, and total peripheral resistance (TPR, ModelFlow) was calculated at rest and during intravenous insulin (n=20) or SNP (n=13) infusion. A subset of participants receiving insulin (n=7) were co‐infused with phenylephrine. Spontaneous arterial baroreflex sensitivity was determined over 5‐min at baseline and during pharmacological intervention(s).ResultsInsulin infusion increased MSNA (p=0.05) and decreased TPR (p&lt;0.05), with no effects on arterial baroreflex sensitivity or BP (p&gt;0.05). Co‐infusion with phenylephrine returned MSNA and TPR to baseline, with no effect on baroreflex sensitivity (p&gt;0.05). Similar to insulin, SNP increased MSNA (p&lt;0.01) and decreased TPR (p&lt;0.05), with no effect on baroreflex sensitivity (p&gt;0.05).ConclusionsPresent findings reveal that acute hyperinsulinemia increases MSNA without a change in arterial baroreflex sensitivity in healthy men and women. Insulin‐mediated increases in MSNA are lost with co‐infusion of phenylephrine and can be recapitulated with infusion of SNP. Results support a dynamic interplay between central and peripheral mechanisms during hyperinsulinemia to increase MSNA and maintain BP.

Experimental uninephrectomy associates with less parasympathetic modulation of heart rate and facilitates sodium-dependent arterial hypertension.

Blood pressure is known to be increased in kidney donors following living-donor kidney transplantation. However, the physiological underpinnings of the blood-pressure increase following uninephrectomy remain unclear. We hypothesized that changes in sympathetic tone or in parasympathetic modulation of sinus node function are involved in the blood-pressure increase following experimental kidney-mass reduction. C57BL6N mice (6 to 11 per group) subjected to sham surgery (controls) or uninephrectomy with or without a one-week course of sodium chloride-enriched, taurine-deficient diet were studied. Uninephrectomized mice treated with a subcutaneous infusion of angiotensin-II over a period of one week were positive controls. A transfemoral aortic catheter with telemetry unit was implanted, readings of heart-rate and blood-pressure were recorded. Powerspectral analysis of heart rate and systolic blood pressure was performed to gain surrogate parameters of sympathetictone and parasympathetic modulation of sinus node function. Baroreflex sensitivity of heart rate was determined from awake, unrestrained mice using spontaneous baroreflex gain technique. Systolic arterial blood pressure, heart rate and baroreflex sensitivity were not different in uninephrectomized mice when compared to controls. Parasympathetic modulation of sinus node function was less in uninephrectomized mice in comparison to controls. Uninephrectomized mice of the high-angiotensin-II model or of the high-salt and taurine-deficiency model had an increased systolic arterial blood pressure. Uninephrectomy associated with less parasympathetic modulation of sinus node function. The combination of uninephrectomy, taurine-deficiency and high-salt intake led to arterial hypertension.

Role of the arterial baroreflex in the sympathetic response to hyperinsulinemia in adult humans.

Muscle sympathetic nerve activity (MSNA) increases during hyperinsulinemia, primarily attributed to central nervous system effects. Whether peripheral vasodilation induced by insulin further contributes to increased MSNA via arterial baroreflex-mediated mechanisms requires further investigation. Accordingly, we examined baroreflex modulation of the MSNA response to hyperinsulinemia. We hypothesized that rescuing peripheral resistance with coinfusion of the vasoconstrictor phenylephrine would attenuate the MSNA response to hyperinsulinemia. We further hypothesized that the insulin-mediated increase in MSNA would be recapitulated with another vasodilator (sodium nitroprusside, SNP). In 33 young healthy adults (28 M/5F), MSNA (microneurography) and arterial blood pressure (BP, Finometer/brachial catheter) were measured, and total peripheral resistance (TPR, ModelFlow) and baroreflex sensitivity were calculated at rest and during intravenous infusion of insulin (n = 20) or SNP (n = 13). A subset of participants receiving insulin (n = 7) was coinfused with phenylephrine. Insulin infusion decreased TPR (P = 0.01) and increased MSNA (P < 0.01), with no effect on arterial baroreflex sensitivity or BP (P > 0.05). Coinfusion with phenylephrine returned TPR and MSNA to baseline, with no effect on arterial baroreflex sensitivity (P > 0.05). Similar to insulin, SNP decreased TPR (P < 0.02) and increased MSNA (P < 0.01), with no effect on arterial baroreflex sensitivity (P > 0.12). Acute hyperinsulinemia shifts the baroreflex stimulus-response curve to higher MSNA without changing sensitivity, likely due to insulin's peripheral vasodilatory effects. Results show that peripheral vasodilation induced by insulin contributes to increased MSNA during hyperinsulinemia.NEW & NOTEWORTHY We hypothesized that elevation in muscle sympathetic nervous system activity (MSNA) during hyperinsulinemia is mediated by its peripheral vasodilator effect on the arterial baroreflex. Using three separate protocols in humans, we observed increases in both MSNA and cardiac output during hyperinsulinemia, which we attributed to the baroreflex response to peripheral vasodilation induced by insulin. Results show that peripheral vasodilation induced by insulin contributes to increased MSNA during hyperinsulinemia.

Patterns of renal and splanchnic sympathetic vasomotor activity in an animal model of survival to experimental sepsis.

Sepsis causes long-term disability, such as immune dysfunction, neuropsychological disorders, persistent inflammation, catabolism, and immunosuppression, leading to a high risk of death in survivors, although the contributing factors of mortality are unknown. The purpose of this experimental study in rats was to examine renal (rSNA) and splanchnic (sSNA) sympathetic nerve activity, as well as baroreflex sensitivity, in acute and chronic post-sepsis periods. The rats were divided into two groups: control group with naïve Wistar rats and sepsis group with 2-mL intravenous inoculation of Escherichia coli at 108 CFU/mL. Basal mean arterial pressure, heart rate, rSNA, sSNA, and baroreflex sensitivity were evaluated in all groups at the acute (6 h) and chronic periods (1 and 3 months). Basal rSNA and sSNA were significantly reduced in the surviving rats, as was their baroreflex sensitivity, for both pressor and hypotensive responses, and this effect lasted for up to 3 months. A single episode of sepsis in rats was enough to induce long-term alterations in renal and splanchnic sympathetic vasomotor nerve activity, representing a possible systemic event that needs to be elucidated. These findings showed that post-sepsis impairment of sympathetic vasomotor response may be one of the critical components in the inability of sepsis survivors to respond effectively to new etiological illness factors, thereby increasing their risk of post-sepsis morbidity.

Effects of Screen Time and Season on Cardiovascular System Indicators in Primary Schoolchildren

Indicators of the cardiovascular system, including heart rate (HR) and blood pressure (BP) variability parameters, were analyzed in primary school students with different computer screen times. The study included 4084 students of grades 1–4 (age 7–12 years) from 66 Moscow schools. The screen time at school and out of school was assessed by teachers, based on the national Sanitary Rules and Regulations: 0, no screen time; 1, screen time matching hygienic standards; 2, screen time at least twice greater than recommended. Physiological examinations were carried out by spiroarteriocardiorhythmography with a face mask, the conditions corresponding to the functional stress test (mild hypercapnia/hypoxia). Testing took place in spring and autumn (independent samples). Statistical data processing was performed using nonparametric criteria. It was revealed that the introduction of computer technologies in school lessons within the limits of hygienic standards was accompanied by an increase, within the normal range, of systolic BP in girls at the end of grade 2 and 4 and in boys at the beginning and end of grade 4. Screen time at least twice higher than the hygienic standard did not have an additional effect on BP, but provoked shifts in the function of autonomic regulation. Boys were more sensitive to the influence of this environmental factor. Their pattern of seasonal variability in total power (TP) of the HR variability spectrum was reversed compared to that of children who did not use computers at school; i.e., higher TP values were observed in spring. In grade 4, the process was accompanied by an increase in spontaneous arterial baroreflex sensitivity and a decrease in the relative power of the LF range in the variability spectrum of systolic BP. The changes were assumed to reflect the adaptive response to changes in educational environment.

Effects of Greater Central Arterial Stiffness on Cardiovagal Baroreflex Sensitivity in Resistance-Trained Men

BackgroundCompared with age-matched untrained men, resistance-trained men who have undergone long duration training (> 2 years) at a high frequency (> 5 days/week) may be lower cardiovagal baroreflex sensitivity (BRS) because of central arterial stiffening. Therefore, the purpose of this study was to examine the effect of greater central arterial stiffness in resistance-trained men on cardiovagal BRS in a cross-sectional study to compare resistance-trained men with age-matched untrained men.MethodsThis cross-sectional study included resistance-trained men (n = 20; age: 22 ± 3; body mass index: 26.7 ± 2.2) and age-matched untrained men (control group: n = 20; age: 25 ± 2; body mass index: 23.7 ± 2.4). The β-stiffness index and arterial compliance were assessed at the right carotid artery using a combination of a brightness mode ultrasonography system for the carotid artery diameter and applanation tonometry for the carotid blood pressure. And, the cardiovagal BRS was estimated by the slope of the R–R interval and systolic blood pressure during Phase II and IV of Valsalva maneuver (VM). The participants maintained an expiratory mouth pressure of 40 mmHg for 15 s in the supine position.ResultsThe β-Stiffness index was significantly higher in the resistance-trained group than in the control group (5.9 ± 1.4 vs. 4.4 ± 1.0 a.u., P < 0.01). In contrast, the resistance-trained group had significantly lower arterial compliance (0.15 ± 0.05 vs. 0.20 ± 0.04 mm2/mmHg, P < 0.01) and cardiovagal BRS during Phase IV of VM (9.0 ± 2.5 vs. 12.9 ± 5.4 ms/mmHg, P < 0.01) than the control group and. Moreover, cardiovagal BRS during Phase IV of VM was inversely and positively correlated with the β-stiffness index (r = − 0.59, P < 0.01) and arterial compliance (r = 0.64, P < 0.01), respectively.ConclusionResistance-trained group had greater central arterial stiffness and lower cardiovagal BRS Phase IV compared with control group. Moreover, the central arterial stiffening was related to cardiovagal BRS Phase IV. These results suggest that greater central arterial stiffness in resistance-trained men may be associated with lower cardiovagal BRS.Trial Registration University hospital Medical Information Network (UMIN) in Japan, UMIN000038116. Registered on September 27, 2019.

Wet Cupping Therapy to The Arterial Baroreflex Sensitivity on Hypertensive Elderly

Wet cupping therapy can remove toxins and prevent atherosclerosis. This process will stimulate the sensitivity of the arterial baroreflex which will stimulate a decrease in blood pressure. This is to determine the impact of cupping therapy on the sensitivity of arterial baroreflex with blood pressure indicators in the elderly suffering from hypertension. Quasi-experimental research using pre and post-test and group control design approaches. The sampling technique was simple random sampling, consisting of 21 respondents which was carried out from January to April 2020. The statistics used the General Linear Model Repeated Measures (GLM-RM) test. There was a significant difference between the sensitivity of arterial baroreflex on blood pressure measurement indicators before and after 2 weeks of follow-up period at systolic BP p-value = 0.000 (24.29 ± 8.11 mmHg) and diastolic BP p-value = 0.001 (5.24 ± 6.02); between 2 weeks and 4 weeks at systolic BP p-value = 0.000 (10.95 ± 6.25 mmHg) and diastolic BP p-value = 0.000 (9.05 ± 6.25 mmHg); Between 4 weeks and 6 weeks there was no significant difference in the sensitivity of arterial baroreflex on the measurement indicator systolic BP p-value = 0.267 (-1.43 ± 5.73) and BP diastole p-value = 0.771 (-0.48 ± 7.40). Wet cupping therapy effectively increases the sensitivity of arterial baroreflex with an indicator of decreasing blood pressure in the elderly suffering from hypertension to a limit of 4 weeks after therapy and measurement after 6 weeks of having increased blood pressure.

Exercise Training Induces Hemodynamic and Autonomic Benefits in a Model of Aterosclerosclerosis

Considering the increase of cardiovascular risk with the progression of the atherogenic process and the effectiveness of physical training as a strategy to control/manage the cardiac dysfunction in populations exposed to elevated risks, the aim of this study was to evaluate the cardiovascular and autonomic effects of an aerobic exercise training protocol in an experimental model of atherosclerosis. Considering the cardioprotective effects already known about physical training the hypothesis of this study is that the aerobic exercise training will promote systemic benefits on hemodynamics and autonomic in a model of atherosclerosis. For this, sixteen ApoE-knockout mice, 15 months old, were divided in 2 groups (n=8, each): sedentary group (APOE 15) and moderate intensity exercise training group (APOE 15T). The exercise training lasted for 6 weeks (5 days/week, 1 hour/day, intensity 60–75% of the maximum treadmill test). At the end of the protocol, the animals were submitted to echocardiography analysis and cannulation for a direct recording of the arterial blood pressure (AP), and then, baroreflex sensitivity and cardiovascular autonomic modulation were evaluated. The aerobic exercise training improved running capacity (APOE 15: 594.90±46.95; APOE 15T: 878.6±68.54 s) and cardiac diastolic function (E/A: APOE 15: 1.10±0.05; APOE 15T: 1.70±0.24), as well as decreased diastolic blood pressure (DAP: APOE 15: 107.0±5.202; APOE 15T: 95.12±0.79 mmHg) and induced resting bradycardia (HR: APOE 15: 704±21; APOE 15T: 613±20 bpm) associated with heart rate variability increase (Var-PI: APOE 15:1.25±0.09; APOE 15T: 8.81±1.98 ms2; SD-Pl: APOE 15: 1.09±0.06; APOE 15T: 2.77±0.37 ms). In addition, greater cardiac parasympathetic modulation (RMSSD: APOE 15: 0.99±0.06; APOE 15T: 1.41±0.10 ms) and baroreflex sensitivity improvement (Alpha Index: APOE 15: 0.31±0.044; APOE 15T: 0.66±0.10 ms/mmHg) were also observed. In conclusion, aerobic exercise training may be considered an important non-pharmacological strategy for the management of cardiovascular risk induced by atherosclerosis, improving running capacity, diastolic function as well as the hemodynamic status and autonomic modulation.

Ten-year follow-up of cardiac function and neural regulation in a group of amateur half-marathon runners

ObjectiveIn the last years, a debate exists about type, intensity and frequency of physical exercise that is really indicated to protect healthy subjects from cardiovascular disease. Regular physical training has...

Resistance training improves cardiac function and cardiovascular autonomic control in doxorubicin-induced cardiotoxicity.

Doxorubicin (DOX) is an anticancer chemotherapy drug that is widely used in clinical practice. It is well documented that DOX impairs baroreflex responsiveness and left ventricular function and enhances sympathetic activity, cardiac sympathetic afferent reflexes and oxidative stress, which contribute to hemodynamic deterioration. Because resistance training (RT)-induced cardioprotection has been observed in other animal models, the objective of this study was to assess the effects of RT during DOX treatment on hemodynamics, arterial baroreflex, cardiac autonomic tone, left ventricular function and oxidative stress in rats with DOX-induced cardiotoxicity. Male Wistar rats were submitted to a RT protocol (3 sets of 10 repetitions, 40% of one-repetition maximum (1RM) of intensity, 3 times per week, for 8weeks). The rats were separated into 3 groups: sedentary control, DOX sedentary (2.5mg/kg of DOX intraperitoneal injection, once a week, for 6weeks) and DOX + RT. After training or time control, the animals were anesthetized and 2 catheters were implanted for hemodynamic, arterial baroreflex and cardiac autonomic tone. Another group of animals was used to evaluate left ventricular function. We found that RT in DOX-treated rats decreased diastolic arterial pressure, heart rate, sympathetic tone and oxidative stress. In addition, RT increased arterial baroreflex sensitivity, vagal tone and left ventricular developed pressure in rats with DOX-induced cardiotoxicity. In summary, RT is a useful non-pharmacological strategy to attenuate DOX-induced cardiotoxicity.

Показатели вариабельности сердечного ритма и артериального давления у подростков с нервно-психическими нарушениями при выполнении нагрузочных проб

Целью настоящего исследования стало изучение особенностей вариабельности сердечного ритма (СР) и вариабельности артериального давления (АД) у подростков с клинически-подтверждённой нервно-психической патологией, при регистрации в условиях функциональной нагрузочной пробы. Методы. Методом спироартериокардиоритмографии проведено тестирование показателей сердечно-сосудистой системы в условиях функциональной нагрузочной пробы (в надетой спирометрической маске, с произвольным дыханием - модель лёгкой гиперкапнии/гипоксии) у учащихся специализированной школы для пациентов психиатрических клиник (на стадии ремиссии) (n = 61), и учащихся общеобразовательной школы (n = 197). Подростки из специализированной школы были разделены на две группы: пациенты с неврологическими диагнозами и последствиями органических поражений мозга (n = 35); пациенты с психическими расстройствами без органических поражений мозга (n = 26). Возраст учащихся из обеих школ составил 12,0-17,7 лет, выборки обеих школ были поделены на 5 возрастных диапазонов (12,0-13,5, 13,6-14,5, 14,6-15,5, 15,6-16,5 и 16,6-17,7 лет). В контрольной школе подростки были дополнительно разделены по полу. Результаты. В возрастных диапазонах 12,0-13,5, 13,6-14,5 и 14,6-15,5 лет статистически значимых различий между учащимися разных школ ни по одному показателю не обнаружено. В возрастном диапазоне 15,6-16,5 лет выявлены более высокие величины систолического и диастолического АД у подростков с неврологическими диагнозами и последствиями органических поражений мозга (по сравнению с контрольными группами). В возрастном диапазоне 16,6-17,7 лет у подростков с психическими расстройствами без органических поражений мозга обнаружены более высокие (по сравнению с контролем) величины стресс-индекса и более низкие (по сравнению с пациентами с неврологическими диагнозами) величины чувствительности спонтанного артериального барорефлекса (на уровне тенденции, p = 0,056). Заключение. Проведённые исследования показали, что по параметрам вариабельности СР и АД подростки с нервно-психической патологией не существенно отличаются от учащихся общеобразовательных школ. Повышение стресс-индекса у подростков с психопатологией без органических поражений мозга в возрасте 16,6-17,7 лет можно интерпретировать как коррелят повышения симпатической активности. У подростков с неврологическими заболеваниями, по-видимому, обнаружена более ранняя по сравнению с контролем манифестация юношеской предгипертензии (в 15,6-16,5 лет). The aim of this study was to assess characteristics of heart rate (HR) and blood pressure (BP) variability in adolescents with clinically confirmed neuropsychiatric pathology in the conditions of a functional test. Methods. The method of spiroarteriocardiorhythmography was used to test cardiovascular parameters during a functional stress test (voluntary breathing with a spirometric mask, a model of mild hypercapnia / hypoxia), in students of a specialized school for patients of psychiatric clinics (in remission) (n = 61) and students of a regular school (n = 197). Adolescents from a specialized school were divided into two groups: 1) patients with neurological diagnoses and consequences of organic brain damage (n = 35) and 2) patients with psychiatric disorders without organic brain damage (n = 26). The age of students from both schools was 12.0-17.7 years; samples of both schools were divided into 5 age ranges (12.0-13.5, 13.6-14.5, 14.6-15.5, 15.6-16.5 and 16.6-17.7 years). The adolescents from the control school were additionally subdivided by gender. Results. In the age ranges of 12.0-13.5, 13.6-14.5, and 14.6-15.5 years, no statistically significant differences were found between students from different schools in any parameters. In the age range of 15.6-16.5 years, adolescents with neurological diagnoses and consequences of organic brain damage had higher values of systolic and diastolic BP compared to the control groups. In the age range of 16.6-17.7 years, adolescents with psychiatric disorders without organic brain damage had higher values of the stress index than in the control groups, and a tendency towards lower values of spontaneous arterial baroreflex sensitivity compared to patients with neurological diagnoses (p = 0.056). Conclusion. Adolescents with neuropsychiatric pathologies did not significantly differ from students of regular schools in parameters of HR and BP variability. The increased stress index in adolescents with psychopathology without organic brain damage aged 16.6-17.7 years can be interpreted as a correlate of elevated sympathetic activity. Adolescents with neurological diseases apparently had an earlier onset of juvenile prehypertension (at 15.6-16.5 years) compared to the control.