Cardiovascular Autonomic Function Research Articles

Sympathetic Overactivity and Parasympathetic Impairment in Type 2 Diabetes: An Analysis of Cardiovascular Autonomic Functions

Sympathetic Overactivity and Parasympathetic Impairment in Type 2 Diabetes: An Analysis of Cardiovascular Autonomic Functions

Exploring Cardiovascular Autonomic Function before and after Chronic Deep Brain Stimulation in Parkinson's Disease.

Blood pressure control in Parkinson's disease (PD) under subthalamic deep brain stimulation (STN-DBS) is influenced by several intertwined aspects, including autonomic failure and levodopa treatment. To evaluate the effect of chronic STN-DBS, levodopa, and their combination on cardiovascular autonomic functions in PD. We performed cardiovascular reflex tests (CRTs) before and 6-months after STN-DBS surgery in 20 PD patients (pre-DBS vs. post-DBS). CRTs were executed without and with medication (med-OFF vs. med-ON). CRT results and occurrence of neurogenic orthostatic hypotension (OH) did not differ between pre- and post-DBS studies in med-OFF condition. After levodopa intake, the BP decrease during HUTT was significantly greater compared to med-OFF, both at pre-DBS and post-DBS evaluation. Levodopa-induced OH was documented in 25% and 5% of patients in pre-DBS/med-ON and post-DBS/med-ON study. Chronic stimulation did not influence cardiovascular responses, while levodopa exerts a relevant hypotensive effect. The proportion of patients presenting levodopa-induced OH decreases after STN-DBS surgery.

Exploring Brainstem Structural Abnormalities: Potential Biomarkers for Panic Disorder.

Panic disorder (PD), characterized by recurrent and intense panic attacks, presents a complex interplay between psychological and neurobiological factors. Although the amygdala and hippocampus have been studied extensively in the context of PD, the brainstem's involvement remains relatively underexplored. This study aims to address this gap by examining structural abnormalities within specific brainstem regions, including the medulla, pons, and midbrain. The study sample population comprised twenty-one adult patients diagnosed with PD and an age-gender-education-matched control group. Utilizing rigorous inclusion and exclusion criteria, confounding factors related to comorbid psychiatric conditions and brain structure abnormalities were minimized. Our findings revealed a significant reduction in medulla volume among PD patients, a finding that persisted even after correcting for individual differences in total intracranial volume. The medulla's role in cardiovascular regulation and autonomic function, coupled with its involvement in fear responses, underscores its potential significance in the pathophysiology of PD. This study elucidates the medulla's structural abnormalities as a potential biomarker for PD. Understanding the role of the brainstem in PD could pave the way for more targeted and effective interventions for this condition.

Cardiac Autonomic and Endothelial Function in Acute Lymphoblastic Leukaemia Patients Immediately After Chemotherapy and at the Three-Month Follow-up.

Acute lymphoblastic leukemia (ALL) is a malignant uncontrolled overproduction of immature lymphoid cells in blood and bone marrow. The primary treatment of ALL is chemotherapy. Chemotherapy can have myriad systemic side effects, notably cardiovascular derangement. Autonomic derangement occurrence in cancer patients signifies cardiovascular risk in them and is a determinant of cardiovascular morbidity and mortality. Elevated soluble vascular cell adhesion molecule-1 (sVCAM-1) and soluble intercellular adhesion molecule-1 (sICAM-1) levels implicated in the regulation of inflammation indicate endothelial dysfunction. High levels of high-sensitivity C-reactive protein (hsCRP) can be indicative of low-grade inflammation. Hence, in this study the cardiac autonomic function and endothelial and inflammatory biomarker levels in adult patients with ALLwere assessed immediately and three months after chemotherapy. In this longitudinal study, 30 ALL patients (23 males, seven females) aged between 18 to 50 years, who had completed chemotherapy regimens, and 30 age and gender-matched healthy participants (controls) were recruited. Cardiac autonomic function tests (short-term heart rate variability (HRV), 30:15 ratio, synaptic excitation and inhibition (E/I) ratio, diastolic blood pressure (DBP) response to isometric hand grip), endothelial markers (sVCAM-1 and sICAM-1), and inflammatory marker (hsCRP) were assessed immediately and at three months after chemotherapy. Magnitudes of time domain and frequency domain indices, conventional autonomic function test indices, and biomarkers were deranged in ALL patients immediately after chemotherapy. After three months, cardiac autonomic function parameters were found to improve in the form of increased root mean square of successive differences between normal heartbeats (RMSSD), standard deviation of the interbeat intervals of normal sinus beats (SDNN), total power, high-frequency (HF)nu, and decreased low-frequency(LF)nu & LF-HF ratio. Endothelial (sVCAM-1) and inflammatory markers (hsCRP) were lower in the patient group as compared to the controls immediately after chemotherapy. Three months after chemotherapy, the levels of endothelial and inflammatory markers did not show much change. In this study, we found ALL patients showed higher sympathetic drive, decreased parasympathetic modulation, and sympathovagal imbalance immediately after chemotherapy as compared to the controls, indicating cardiovascular risk. After three months, improvement in cardiovascular autonomic function was observed. ALL itself is a state of inflammation with elevated endothelial and inflammatory markers; thus, the decreased endothelial and inflammatory markers could be attributed to the immediate effect of chemotherapy.

Central Autonomic Mechanisms Involved in the Control of Laryngeal Activity and Vocalization.

In humans, speech is a complex process that requires the coordinated involvement of various components of the phonatory system, which are monitored by the central nervous system. The larynx in particular plays a crucial role, as it enables the vocal folds to meet and converts the exhaled air from our lungs into audible sounds. Voice production requires precise and sustained exhalation, which generates an air pressure/flow that creates the pressure in the glottis required for voice production. Voluntary vocal production begins in the laryngeal motor cortex (LMC), a structure found in all mammals, although the specific location in the cortex varies in humans. The LMC interfaces with various structures of the central autonomic network associated with cardiorespiratory regulation to allow the perfect coordination between breathing and vocalization. The main subcortical structure involved in this relationship is the mesencephalic periaqueductal grey matter (PAG). The PAG is the perfect link to the autonomic pontomedullary structures such as the parabrachial complex (PBc), the Kölliker-Fuse nucleus (KF), the nucleus tractus solitarius (NTS), and the nucleus retroambiguus (nRA), which modulate cardiovascular autonomic function activity in the vasomotor centers and respiratory activity at the level of the generators of the laryngeal-respiratory motor patterns that are essential for vocalization. These cores of autonomic structures are not only involved in the generation and modulation of cardiorespiratory responses to various stressors but also help to shape the cardiorespiratory motor patterns that are important for vocal production. Clinical studies show increased activity in the central circuits responsible for vocalization in certain speech disorders, such as spasmodic dysphonia because of laryngeal dystonia.

Genetic Factors Associated with the Development of Neuropathy in Type 2 Diabetes.

Neuropathy is a serious and frequent complication of type 2 diabetes (T2DM). This study was carried out to search for genetic factors associated with the development of diabetic neuropathy by whole exome sequencing. For this study, 24 patients with long-term type 2 diabetes with neuropathy and 24 without underwent detailed neurological assessment and whole exome sequencing. Cardiovascular autonomic function was evaluated by cardiovascular reflex tests. Heart rate variability was measured by the triangle index. Sensory nerve function was estimated by Neurometer and Medoc devices. Neuropathic symptoms were characterized by the neuropathy total symptom score (NTSS). Whole exome sequencing (WES) was performed on a Thermo Ion GeneStudio S5 system determining the coding sequences of approximately 32,000 genes comprising 50 million base pairs. Variants were detected by Ion Reporter software and annotated using ANNOVAR, integrating database information from dbSNP, ClinVar, gnomAD, and OMIM. Integrative genomics viewer (IGV) was used for visualization of the mapped reads. We have identified genetic variants that were significantly associated with increased (22-49-fold) risk of neuropathy (rs2032930 and rs2032931 of recQ-mediated genome instability protein 2 (RMI2) gene), rs604349 of myosin binding protein H like (MYBPHL) gene and with reduced (0.07-0.08-fold) risk (rs917778 of multivesicular body subunit 12B (MVB12B) and rs2234753 of retinoic acid X receptor alpha (RXRA) genes). The rs2032930 showed a significant correlation with current perception thresholds measured at 5 Hz and 250 Hz for n. medianus (p = 0.042 and p = 0.003, respectively) and at 5 Hz for n. peroneus (p = 0.037), as well as the deep breath test (p = 0.022) and the NTSS (p = 0.023). The rs2032931 was associated with current perception thresholds (p = 0.003 and p = 0.037, respectively), deep breath test (p = 0.022), and NTSS (p = 0.023). The rs604349 correlated with values measured at 2000 (p = 0.049), 250 (p = 0.018), and 5 Hz (p = 0.005) for n. medianus, as well as warm perception threshold measured by Medoc device (p = 0.042). The rs2234753 showed correlations with a current perception threshold measured at 2000 Hz for n. medianus (p = 0.020), deep breath test (p = 0.040), and NTSS (p = 0.003). There was a significant relationship between rs91778 and cold perception threshold (p = 0.013). In our study, genetic variants have been identified that may have an impact on the risk of neuropathy developing in type 2 diabetic patients. These results could open up new opportunities for early preventive measures and might provide targets for new drug developments in the future.

Cardiovascular autonomic nervous function in children conceived by assisted reproductive technology with frozen or fresh embryo transfer.

As a result of epigenetic changes, children conceived by assisted reproduction may be at risk of premature cardiovascular aging with notably increased blood pressures. Their cardiovascular autonomic nervous function is unknown. Therefore, this study investigated the cardiovascular autonomic nervous function in 8-12-yr-old children (51% girls) conceived naturally (n = 33) or by assisted reproduction with frozen (n = 34) or fresh (n = 38) embryo transfer by evaluating heart rate variability, during rest; from provocation maneuvers; and from baroreflex function. Heart rate and blood pressure response to provocation maneuvers and baroreflex function were comparable between children conceived naturally or by assisted reproduction. The mean RR-interval and high-frequency component of heart rate variability were lower in children conceived by assisted reproduction than in children conceived naturally. Children conceived by fresh embryo transfer had ∼17% lower heart rate-corrected standard deviation of normal-to-normal R-R intervals; ∼22% lower heart rate-corrected square root of the mean of the squared difference between successive R-R intervals; and ∼37% higher low-frequency/high-frequency ratio than naturally conceived children. Children conceived by assisted reproduction still had lower heart rate variability and vagal modulation than naturally conceived children after adjustment for confounders. Thus, these results raise the possibility of sympathetic predominance in children conceived by assisted reproduction. Therefore, it is important to reproduce these results in larger and older cohorts as sympathetic predominance relates with cardiovascular and metabolic diseases.NEW & NOTEWORTHY We observed that children conceived by assisted reproductive technology (both frozen and fresh embryo transfer) had lowered heart rate variability during rest as compared with children conceived naturally. During physiological stress maneuvers, however, the cardiovascular autonomic nervous regulation was comparable between children conceived by assisted reproductive technologies and naturally. Our findings highlight the potential that lowered heart rate variability during rest in children conceived by assisted reproductive technologies may precede premature hypertension.

Association between heart rate variability and neutrophil-lymphocyte ratio in individuals with prehypertension – A cross-sectional study

Background: High blood pressure, commonly termed hypertension, is becoming more common in both developing and industrialized nations, making it a worldwide health concern. An increase in blood pressure is broadly categorized into prehypertension and hypertension based on JNC VIII criteria. Prehypertension is a state in between normal blood pressure and high blood pressure, and it is linked with injury to target organs and subclinical atherosclerosis an easy and non-invasive way to look into autonomic dysfunction in those who are pre-hypertensive is to measure heart rate variability (HRV). Neutrophil-to-lymphocyte ratio (NLR) is a cheap, simple, and novel hematological parameter of oxidative stress and pro-inflammatory marker and has recently emerged as a useful indicator to predict cardiovascular risk and adverse outcomes in patients with hypertension. Aims and Objectives: The aim of the study is to assess the correlation between cardiovascular autonomic function using HRV and NLR in pre-hypertensive individuals and to find out if NLR can be used as a marker to detect autonomic dysfunction. Materials and Methods: HRV is recorded in a supine position with eyes closed in the study population. About 2 mL of venous blood was collected from the individuals to measure NLR using an automated hematology analyzer. Results: The mean values of time domain indices showed significant reduction and frequency domain indices low frequency (LF) values were significantly higher and high frequency (HF) values were significantly lower in pre-hypertensive. The mean NLR was significantly higher in pre-hypertensive individuals. Time domain indices showed a negative correlation with NLR. HF values were negatively correlated and LF values were positively correlated with NLR. Conclusion: NLR was increased in pre-hypertensive individuals which suggest that people in pre-hypertensive state are also at risk of developing cardiovascular and cerebrovascular complications. This study showed a positive association between NLR and sympathetic activity and a negative association between NLR and parasympathetic activity. This concludes that NLR could be used as a marker to assess autonomic dysfunction in them.

A pilot study to assess the origin of the spectral power increases of heart rate variability associated with transient changes in the R-R interval.

Spectral analysis of heart rate variability (HRV) is used to assess cardiovascular autonomic function. In the power density spectrum calculated from a time series of the R-R interval (RRI), three main components are distinguished: very-low-frequency (VLF; 0.003-0.04 Hz), low-frequency (LF; 0.04-0.15 Hz), and high-frequency (HF; 0.15-0.4 Hz) components. However, the physiological correlates of these frequency components have yet to be determined. In this study, we conducted spectral analysis of data segments of various lengths (5, 30, 100, and 200 s) of the RRI time series during active standing. Because of the trade-off relationship between time and frequency resolution, the analysis of the RRI data segment shorter than 30 s was needed to identify the temporal relationships between individual transient increases in RRI and the resulting spectral power changes. In contrast, the segment of 200 s was needed to properly evaluate the magnitude of the increase in the VLF power. The results showed that a transient increase in the RRI was tightly associated with simultaneous increases in the powers of the VLF, LF, and HF components. We further found that the simultaneous power increases in these three components were caused by the arterial baroreceptor reflex responding to rapid blood pressure rise.

Correlation between Cardiovascular Autonomic and Pulmonary Ventilation Functions in Myasthenia Gravis Patients.

This study aimed to investigate the relationship between pulmonary function and cardiac autonomic function parameters in clinically stable myasthenia gravis (MG) patients. A total of 22 MG patients and 22 healthy controls (HCs) were evaluated. Pulmonary function test parameters, heart rate variability (HRV), baroreflex sensitivity (BRS), and cardiovascular autonomic function test parameters (the Valsalva ratio, expiration/inspiration (E/I) ratio) were assessed. Compared with the HCs, the patients demonstrated a similar diffusion capacity for carbon monoxide (DLCO); a lower forced vital capacity (FVC%pred); a lower forced expiratory volume in 1 s (FEV1%pred); lower BRS and HRV, including high-frequency and total power spectral density; and a higher percentage of abnormal cardiovagal function test results (p < 0.05). A lower BRS in the patient group was associated with worse clinical disease outcomes and reduced pulmonary function (DLCO%pred, R = 0.59; TLC%pred, R = 0.48). Age, forced vital capacity, and total lung capacity predicted the E/I ratio (R2 values ranging from 0.48 to 0.49). Our study demonstrated a significant relationship between a reduced pulmonary ventilation function and respiratory mechanics with cardiovascular autonomic parameters, including the E/I ratio, BRS, and HRV measures at rest, as shown in the MG group. Future studies should focus on the interplay between respiratory and autonomic function testing, as well as pulmonary rehabilitation, to mitigate cardiovascular risk in these patients.

The role of maternal hormones in regulating autonomic functions during pregnancy.

Offspring development relies on numerous physiological changes that occur in a mother's body, with hormones driving many of these adaptations. Amongst these, the physiological functions controlled by the autonomic nervous system are required for the mother to survive and are adjusted to meet the demands of the growing foetus and to ensure a successful birth. The hormones oestrogen, progesterone, and lactogenic hormones rise significantly during pregnancy, suggesting they may also play a role in regulating the maternal adaptations linked to autonomic nervous system functions, including respiratory, cardiovascular, and thermoregulatory functions. Indeed, expression of pregnancy hormone receptors spans multiple brain regions known to regulate these physiological functions. This review examines how respiratory, cardiovascular, and thermoregulatory functions are controlled by these pregnancy hormones by focusing on their action on central nervous system circuits. Inadequate adaptations in these systems during pregnancy can give rise to several pregnancy complications, highlighting the importance in understanding the mechanistic underpinnings of these changes and potentially identifying ways to treat pregnancy-associated afflictions using hormones.

Sudoscan as substitute for quantitative sudomotor axon reflex test in composite autonomic scoring scale and its correlation with composite autonomic symptom scale 31 in type 2 diabetes

ObjectiveThis study aims to evaluate the feasibility of substituting electrochemical skin conductance measurement using SUDOSCAN for sudomotor function testing in the Composite Autonomic Scoring Scale (CASS) and to correlate the results with the Composite Autonomic Symptom Scale 31 (COMPASS 31) among patients with type 2 diabetes mellitus (T2DM). MethodsFifty patients with T2DM underwent cardiovascular autonomic function testing and the SUDOSCAN test and completed the COMPASS 31 questionnaire. We developed a SUDOSCAN-based sudomotor subscore as a substitute for the original sudomotor subscore (based on the quantitative sudomotor axon reflex test [QSART]). The modified CASS score (SUDOSCAN-based sudomotor subscore combined with the adrenergic and cardiovagal subscores) and the original CASS score without suomotor assessment (sum of the adrenergic and cardiovagal subscores) were obtained according to the results of the cardiovascular autonomic function and SUDOSCAN tests. ResultsThe total COMPASS 31 score was significantly correlated with the modified CASS score (p = 0.019 and 0.037 for the raw and weighted scores, respectively) but not with the CASS score without sudomotor assessment. After adding the SUDOSCAN-based sudomotor subscore, the number of patients identified as having diabetic autonomic neuropathy (DAN) increased from 24 (48 %, based on the CASS score without sudomotor assessment) to 35 (70 %, based on the modified CASS score). The modified CASS score enhances the accuracy of assessing autonomic function and improves the diagnosis of diabetic autonomic neuropathy (DAN) among patients with T2DM. In medical settings where QSART is not accessible, SUDOSCAN testing offers a practical and efficient alternative.

EXERGAMES AND CARDIOVASCULAR AND MOTOR ADAPTATIONS IN FEMALE ADOLESCENTES: AN INTERVENTION STUDY

Objective: to analyze the contribution of a physical conditioning program with exergames on postural control and to compare cardiovascular autonomic function among female adolescents.&#x0D; Methods: longitudinal study with overweight and non-overweight female adolescents, aged between 10 and 16 years, submitted to two assessments, when heart rate variability (HRV) and postural control were investigated during participation in the conditioning program with exergames&#x0D; Results: HRV indices for the time domain (RMSS and SDNN), showed significant differences between the pre and post moments of the program with exergames (14.67 [5.86; 22.72]; 12.38 [4, 82; 20.88]), respectively. In postural conditions BPA/AO open base with parallel feet and open eyes (0.19 [0.05; 0.32]), BTD/AO (semi-tandem base with straight forward foot and open eyes) (-0.17 [-0.32; -0.01]), BTD/OF (semi-tandem base with straight forward feet and eyes closed) (-0.21 [-0.38; -0.04]) and BTE/OF (semi-tandem base with left foot forward and eyes closed) (-0.2 [-0.38; -0.02]) differences were found between the pre and post moments of the muscle activation values of the flexor and extensor muscles of the ankle. The same adjustments were not identified for the overweight group. The total displacement of the pressure center in the BTD/AO postures (0.19 [0.02; 0.36]) in the eutrophic group (with adequate weight), and in the BTE/OF (0.77 [0.18; 1.41]) in the overweight group, in pre and post comparisons, statistically significant differences were found.&#x0D; Conclusion: exergames can contribute to physiological adaptations to cardiovascular and motor levels in adolescents.&#x0D;  

Enhancing Cardiovascular Health and Functional Recovery in Stroke Survivors: A Randomized Controlled Trial of Stroke-Specific and Cardiac Rehabilitation Protocols for Optimized Rehabilitation.

Stroke is a major contributor to disability and mortality globally. It leads to physical impairments, including weakness and cardiovascular deconditioning, posing significant challenges to stroke survivors' quality of life. Exercise-based cardiac rehabilitation has shown promise as a rehabilitation strategy. This study aims to assess and compare the impacts of stroke-specific rehabilitation and individualized cardiac rehabilitation exercises on various health parameters in stroke patients. A randomized controlled trial was conducted, involving 38 stroke patients aged 40-75 years. Group A received stroke-specific rehabilitation, which consisted of a combination of range of motion exercises, strength training for the paralyzed side, balance and coordination training, gait training, functional mobility exercises, neuromuscular reeducation, and breathing exercises. This program was conducted five days per week for 12 weeks. Group B received individually designed cardiac rehabilitation exercises, in addition to stroke-specific rehabilitation. They engaged in this exercise for at least 30-45 min per day, four days per week, and incorporated two days of resistive training over a 12-week period. Baseline and post-intervention assessments included measures of cardiac autonomic function, balance (Berg Balance Scale), mobility (Timed Up and Go Test), cardiovascular fitness indicators, respiratory parameters, exercise efficiency, and perceived exertion. Group B receiving individualized cardio rehab showed significant improvements in balance and mobility compared to Group A receiving conventional stroke-specific rehab. Moreover, Group B exhibited enhanced cardiovascular fitness, respiratory performance, exercise efficiency, and autonomic function post-intervention. Notably, Group A displayed no significant improvements in these parameters. Individualized cardiac rehabilitation exercises demonstrated favorable outcomes in improving certain health parameters, highlighting the potential benefits of individualized rehabilitation strategies for stroke patients.

Unraveling Autonomic Dysfunction in GBA-Related Parkinson's Disease.

Patients with Parkinson's disease (PD) and GBA gene mutations (GBA-PD) develop nonmotor complications more frequently than noncarriers. However, an objective characterization of both cardiovascular and sudomotor autonomic dysfunction using extensive clinical and instrumental measures has never been provided so far. Survival is reduced in GBA-PD regardless of age and dementia, suggesting that other hitherto unrecognized factors are involved. To provide instrumental measures of pattern and severity of autonomic dysfunction in GBA-PD and explore their correlation with other non-motor symptoms and implications for clinical practice. In this cross-sectional study, 21 GBA-PD and 24 matched PD noncarriers underwent extensive assessment of motor and non-motor features, including neuropsychological testing. Cardiovascular autonomic function was explored through a comprehensive battery of indexes, including power spectral analysis of the R-R intervals and blood pressure short-term variability during resting state and active maneuvers. Dynamic Sweat Test was used to assess post-ganglionic sudomotor dysfunction. Despite minimal or absent clinical correlates, cardiovagal and sympathetic indexes, heart rate variability parameters and sudomotor postganglionic function were more severely impaired in GBA-PD than noncarriers (overcoming relatively preserved compensatory peripheral sympathetic function), suggesting more prominent cardiac sympatho-vagal demodulation, efferent baroreflex failure and peripheral sympathetic dysfunction in GBA-PD. Cardiovascular dysautonomia showed marginal correlations with cognitive impairment. Compared to PD noncarriers, GBA-PD display more severe instrumental autonomic abnormalities, which may be underestimated by purely clinical measures, despite their relevance on morbidity and mortality. This supports the necessity of implementing instrumental autonomic assessment in all GBA-PD, regardless of clinically overt symptoms.

Relationships between cardiovascular disease risk, neuropathic pain, mental health, and autonomic function in chronic spinal cord injury.

Multicentre, cross-sectional study. To determine if clinical measures of poor mental health (MH-) and neuropathic pain (NP) are related to increased CVD risk in individuals with chronic spinal cord injury (SCI), and further elucidate the relationships between CVD risk, autonomic function, NP, and MH-. Eight SCI rehabilitation centres in the Netherlands. Individuals (n = 257) with a traumatic, chronic (≥10 yrs) SCI, with age at injury between 18-35 years, completed a self-report questionnaire and a one-day visit to a rehabilitation centre for testing. CVD risk was calculated using Framingham risk score. NP was inferred using The Douleur Neuropathique 4 clinical examination, and MH- was assessed using the five-item Mental Health Inventory questionnaire. Cardiovascular autonomic function was determined from peak heart rate during maximal exercise (HRpeak). There was a high prevalence of both NP (39%) and MH- (45%) following SCI. MH- was significantly correlated with an adverse CVD risk profile (r = 0.174; p = 0.01), increased the odds of adverse 30-year CVD risk by 2.2 (CI 0.92-2.81, p = 0.02), and is an important variable in determining CVD risk (importance=0.74, p = 0.05). Females (p = 0.05) and those with a higher HRpeak (p = 0.046) tended to be more likely to have NP. Clinical measures of MH-, but not NP, are important factors for increased CVD risk following SCI. NP tended to be more prevalent in those with more preserved cardiovascular autonomic function. The interrelationships between secondary consequences of SCI are complex and need further exploration.

Parental History of Hypertension: A Risk for Autonomic Dysfunction and Metabolic and Vascular Derangement in Normotensive Male Offspring.

Children of hypertensive parents have an increased propensity of developing hypertension, at an age very much prior to their parents. Understanding the pathophysiology of hypertension in such young individuals, especially baroreflex sensitivity (BRS), is necessary. Reduced heart rate variability (HRV), insulin resistance (IR), dyslipidemia, and decreased vasodilatory adipokines, namely, apelin and relaxin, in normotensives may predispose to the onset of hypertension. Thus, this study compared autonomic functions, vascular markers, and metabolic profiles between normotensive male offspring with and without parental hypertension. This analytical cross-sectional study comprised 40 male normotensive offspring of hypertensive parents, aged 18-35 years, recruited as the study group and 40 age- and body mass index (BMI)-matched normotensive male offspring with non-hypertensive parents enrolled as controls. Cardiovascular autonomic functions, including BRS, HRV, diastolic blood pressure response to isometric handgrip test (ΔDBPIHG), Valsalva ratio, and metabolic and vascular markers, were assessed. The study group exhibited reduced BRS, HRV, and Valsalva ratio and higher ΔDBPIHG compared to controls, indicating impaired autonomic functions. The study group had higher IR and triglyceride levels and reduced apelin and relaxin levels. BRS showed significant correlations with HRV, Valsalva ratio, ΔDBPIHG, and metabolic and vascular markers. Normotensive male offspring of hypertensive parents exhibit impaired autonomic functions, as evidenced by reduced BRS, HRV, and Valsalva ratio. Additionally, they have higher IR, dyslipidemia, and decreased levels of vasodilatory adipokines, indicating an increased risk for future hypertension development. These findings signify that early identification of hypertensive potential in this high-risk population is warranted, which would enable taking necessary preventive measures.

Prevalence of cardiac autonomic neuropathy in patients with type 2 diabetes mellitus.

Cardiac autonomic neuropathy (CAN) is one of the microvascular complications of diabetes mellitus, which is due to the involvement of autonomic nerve fibers innervating the heart and blood vessels. CAN was found to have a greater degree of morbidity and mortality than their non-CAN counterparts as it is underdiagnosed. Hence, this study aims to determine the prevalence and severity of CAN in type 2 diabetics in the South Indian setting. Forty-two patients with type 2 diabetes mellitus were enrolled in the study. Patients underwent tests for CAN, with the severity of CAN estimated as a CAN score, which was the sum of the scores of the four cardiovascular autonomic function tests. Out of the 42 patients, a total of 36 patients (85.7%) were diagnosed with CAN. Among those with CAN, 24 patients had early CAN (57.1%), and 12 were diagnosed with definite CAN (28.6%). Patients with any form of CAN (early and definite CAN) had higher HbA1c and mean glucose values than those without CAN. CAN was also found to be more severe among older patients with diabetes. In the present study, we found that more than 50% of the study population had early CAN and around 28.6% patients had definite CAN indicating higher prevalence of CAN in our population. Also, there was a positive correlation between the severity of CAN and the age of the patients. This study highlights the importance of understanding the importance of screening the diabetic patients for CAN to prevent adverse cardiovascular events.

Association of gender with cardiovascular and autonomic responses to central hypovolemia.

Lower body negative pressure (LBNP) eliminates the impact of weight-bearing muscles on venous return, as well as the vestibular component of cardiovascular and autonomic responses. We evaluated the hemodynamic and autonomic responses to central hypovolemia, induced by LBNP in both males and females. A total of 44 participants recruited in the study. However, 9 participants did not complete the study protocol. Data from the remaining 35 participants were analysed, 18 males (25.28 ± 3.61 years, 181.50 ± 7.43 cm height, 74.22 ± 9.16 kg weight) and 17 females (22.41 ± 2.73 years, 167.41 ± 6.29 cm height, 59.06 ± 6.91 kg weight). During the experimental protocol, participants underwent three phases, which included 30 min of supine rest, four 4 min intervals of stepwise increases in LBNP from -10 mmHg to -40 mmHg, and 5 min of supine recovery. Throughout the protocol, hemodynamic variables such as blood pressure, heart rate, stroke index, cardiac index, and total peripheral resistance index were continuously monitored. Autonomic variables were calculated from heart rate variability measures, using low and high-frequency spectra, as indicators of sympathetic and parasympathetic activity, respectively. At rest, males exhibited higher systolic (118.56 ± 9.59 mmHg and 110.03 ± 10.88 mmHg, p < 0.05) and mean arterial (89.70 ± 6.86 and 82.65 ± 9.78, p < 0.05) blood pressure as compared to females. Different levels of LBNP altered hemodynamic variables in both males and females: heart rate [F(1,16) = 677.46, p < 0.001], [F(1,16) = 550.87, p < 0.001]; systolic blood pressures [F(1,14) = 3,186.77, p < 0.001], [F(1,17) = 1,345.61, p < 0.001]; diastolic blood pressure [F(1,16) = 1,669.458, p < 0.001], [F(1,16) = 1,127.656, p < 0.001]; mean arterial pressures [F(1,16) = 2,330.44, p < 0.001], [F(1,16) = 1,815.68, p < 0.001], respectively. The increment in heart rates during LBNP was significantly different between both males and females (p = 0.025). The low and high-frequency powers were significantly different for males and females (p = 0.002 and p = 0.001, respectively), with the females having a higher increase in low-frequency spectral power. Cardiovascular activity and autonomic function at rest are influenced by gender. During LBNP application, hemodynamic and autonomic responses differed between genders. These gender-based differences in responses during central hypovolemia could potentially be attributed to the lower sympathetic activity in females. With an increasing number of female crew members in space missions, it is important to understand the role sex-steroid hormones play in the regulation of cardiovascular and autonomic activity, at rest and during LBNP.

A three-month physical training program improves cardiovascular autonomic function in patients with metabolic syndrome with and without diabetes - a pilot study.

Vascular complications and neuropathy may develop in the presence of metabolic syndrome. The aim of our study was to measure the cardiovascular autonomic function following physical training in patients with metabolic syndrome with and without diabetes. 56 patients with metabolic syndrome (32 men/24 women, 40 non-diabetic patients (NDMetS)/16 diabetic patients (DMetS) [mean ± SD]: age: 50.35 ± 8.03 vs. 56.8 ± 9.30 years, p=0.023; baseline BMI: 32.2 ± 7.03 vs. 32.8 ± 5.94 kg/m2, p=0.739) were involved in our study. All tests and measurements were carried out before and following a 3-month physical training period. Autonomic function was assessed by means of five standard cardiovascular reflex tests. ECG repolarization parameters, including short-term QT variability and stress-ECG were also measured. In the whole population, Valsalva-ratio (VR) and the autonomic score (AS) improved following training (VR: 1.49 ± 0.24 vs. 1.64 ± 0.34, p=0.001; AS: 2.05 ± 1.73 vs. 1.41 ± 1.36, p=0.015) accompanied by the significant decrease of the systolic (150.3 ± 16.12 vs. 134.1 ± 16.67 mmHg, p<0.001) and diastolic (90.64 ± 12.8 vs. 82.79 ± 11.1 mmHg, p<0.001) blood pressure. An improvement in VR was detected in NDMetS patients following training (1.51 ± 0.24 vs. 1.67 ± 0.31, p= 0.002). No significant changes could be detected in autonomic tests' results in the DMetS patient group following training. The applied exercise training program did not lead to significant changes in ECG repolarization. The stress-ECG test in the whole study population yielded a significant increase in the test duration (12.9 ± 3.76 vs. 15.1 ± 2.96min, p<0.001) and in the test load (10.5 ± 2.78 vs. 11.6 ± 2.39 MET, p<0.001). The load capability improved significantly in both subgroups: 11.1 ± 2.04 vs. 12.1 ± 1.82, (p<0.001) and 9.0 ± 3.64 vs. 10.4 ± 3.05, (p=0.033) in subpopulations of NDMetS and DMetS, respectively. The DMetS patients achieved a significantly lower MET score at baseline (p=0.039) and following training (p=0.044) in comparison to the NDMetS patients. The three-month exercise program improved the Valsalva-ratio and the AN score in the MetS patients, that is potentially protective against cardiovascular events. The training had some beneficial effect on blood pressure and the results of the stress-ECG tests in both groups. The absence of significant change in the reflex tests in DMetS group reflects an impaired adaptation compared to the NDMestS group.