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Objective. Non-motor symptoms including those reflecting autonomic cardiovascular dysregulation are often present in Parkinson disease. It is unclear whether it is possible to detect cardiovascular autonomic dysregulation in the very early stage of Parkinson disease potentially supporting the concept of the upstream propagation of nervous system damage through autonomic nerves. We hypothesized that cardiovascular dysregulation should precede the motor symptoms and at the time of their occurrence autonomic dysregulation should be clearly demonstrable. Therefore, the aim of this study was to assess the various aspects of autonomic cardiovascular control in the very early stage of Parkinson disease. Approach. We performed prospective case-control study on 19 patients with Parkinson disease (<6 months after motor signs occurrence) and 19 healthy control subjects. For each phase of study protocol (supine, head-up tilt, supine recovery), we calculated a wide array of cardiovascular control related parameters reflecting cardiac chronotropic, cardiac inotropic and vasomotor control and baroreflex mediated cardiovascular response. Main results. We observed the well-preserved heart rate and blood pressure control in patients with early stage of Parkinson disease. However, causal analysis of interactions between heart rate and blood pressure oscillations revealed subtle differences in baroreflex function and baroreflex mediated vasoconstriction response to orthostasis. Furthermore, a tendency towards a decreased contraction strength in Parkinson disease was observed. Significance. Considering only subtle cardiovascular control impairment in our study employing a wide array of sensitive methods at the time when motor signs were clearly expressed, we suggest that motor signs dominated in this stage of Parkinson disease. [ABSTRACT FROM AUTHOR]

Arterial compliance (AC) decrease with aging is accelerated by factors associated with the progression of atherosclerotic process, including obesity. Prevalence of obesity increases not only in adult population but also in children and adolescents. The results of studies characterizing the effect of obesity on AC (often indirectly estimated by pulse wave velocity (PWV)) are contradictory. Considering the limitations of previously applied methods and the need to interpret AC values in the context of potential confounders or during various physiological states, the aim of this study was to compare AC of control and obese adolescents during four different physiological states: supine rest, head-up tilt (HUT), supine recovery and mental arithmetic (MA). AC was assessed by the method based on two-element Windkessel model as the ratio of a time constant t characterizing diastolic blood pressure decay and total peripheral resistance (TPR). In total, fifty healthy and normotensive subjects (40 females, 10 males, age 17.5 years (SD=1.1 years)) were examined - 25 obese and 25 age- and sex-matched control subjects. We observed significantly increased AC values during all phases in obese group. An increase in AC was also preserved after controlling for blood pressure influence. These results were confirmed using PWV based AC estimation. Interestingly, AC decreased similarly during stress phases (HUT, MA) in both groups. Lastly, TPR was decreased throughout the study protocol in obese subjects. In conclusion, AC is increased in young obese subjects consistently during various physiological states. Furthermore, changes of physiological states evoke similar response of AC in both groups indicating preserved autonomic control of elastic arteries. A decreased TPR in obese subjects points towards the influence of different maturation state of the arterial tree and/or changes in vasomotion possibly counterbalancing acceleration of atherosclerosis process. [ABSTRACT FROM AUTHOR]

Cardiac stroke volume variation (SVV) measurement is one of the techniques to detect fluid-responsive hypovolemia in patients under mechanical ventilation. There is an ongoing effort to apply SVV for this purpose also in conscious patients. However, the effect of mental stress often occurring in conscious patients as a potential confounding factor on SVV is not known. The aim of our study was to compare effect of simulated hypovolemia and mental stress on SVV in healthy volunteers in the context of potential confounders - breathing pattern, respiratory sinus arrhythmia magnitude and sex. We examined 102 young healthy volunteers (58 females), mean age 18.6 years. Finger arterial blood pressure was recorded by volume-clamp photoplethysmographic method (Finometer Pro, FMS, Amsterdam, Netherland). From the blood pressure curve, a built in Model Flow algorithm calculated stroke volume values (SV) for each heartbeat. Respiratory volume was recorded using calibrated respiratory inductive plethysmography (RespiTrace, NIMS, Miami Beach, FL, USA). During four phases of examination protocol (supine rest, head-up tilt (HUT), supine recovery, mental arithmetic task (MA)) we analyzed SVV related to respiratory activity. While during HUT we found an expected increase in SVV together with mean SV decrease, SVV significantly decreased during MA. The observed changes during MA could be attributed to an increased respiratory rate and/or decreased respiratory sinus arrhythmia. Sex related differences in SVV responses to HUT and MA were observed. We conclude that mental stress together with respiratory sinus arrhythmia and respiratory pattern changes can significantly influence SVV as a potential index of fluid responsiveness in conscious patients. [ABSTRACT FROM AUTHOR]

Obesity is considered an important factor contributing to the development of atherosclerosis. Inflammation plays a key role in endothelial dysfunction (ED), an initial stage of the atherosclerotic process. Several microRNAs (miRNAs) may play an important role in the inflammatory process, but there is a lack of information about their participation in the early stages of atherosclerosis development in patients with obesity. We aimed to assess the relations between plasma concentration of selected miRNAs, ED evaluated by reactive hyperemia index (RHI), inflammatory markers and other factors involved in the pathogenesis of atherosclerosis in adolescents and young adults with obesity. Participants (30 males, 30 females; aged 15 25 years) were divided into two groups: those with overweight/obesity (OW/O) (20 males, 20 females) and controls (C) (10 males, 10 females). The plasma concentrations of inflammatory markers, cytokines, adipocytokines, markers of lipid profile and glucose metabolism and selected miRNAs (miR 92, 126, -146a, -155) were analyzed. No significant differences in any of the miRNAs were found between the groups. MiR-146a correlated positively with RHI. Dividing the group by sex showed more significant associations between miRNA and analyzed parameters (IL-6, fasting glycemia) in men. Several observed correlations indicate a potential role of miRNAs in inflammation, the atherosclerotic process and glycemic control, primarily in male subjects with obesity. The relatively low number of observed associations between assessed parameters related to obesity and the pathogenesis of its complications could be attributed to the early stage of the atherosclerotic process in young subjects with obesity, where only subtle abnormalities are expectedly found. Key words Endothelial dysfunction, Atherosclerosis, Obesity, MicroRNA, Reactive hyperemia index.

Dim light at night (dLAN) has become a pervasive part of the modern world, and growing evidence shows its association with increased health risks. Though this link is attributed to a disturbed circadian clock, the underlying mechanisms that can explain how circadian disruption from dLAN causes negative health effects remain unclear. Here, we exposed rats to a light-dark cycle (12:12 h) with low-intensity light at night (~2 lx) for 2 and 5 weeks and explored the steady-state pattern of circulating immune cells and renal immune-related markers, which are well controlled by the circadian clock. After 5 weeks, dLAN impaired the daily variation in several types of white blood cells, especially monocytes and T cells. Two-week dLAN caused a reduction in blood monocytes and altered gene expression of macrophage marker Cd68 and monocyte-attracting chemokine Ccl2 in the kidney. Interestingly, dLAN decreased renal 3-nitrotyrosine levels and resulted in up-regulation of the main endogenous antioxidant pathways, indicating a disturbance in the renal redox balance and an activation of compensatory mechanisms. These effects paralleled the altered renal expression of the molecular clock components and increased plasma corticosterone levels. Together, our results show that chronic exposure to dLAN weakened the circadian control of daily variation of circulating immune cells and disturbed renal immune and redox homeostasis. Consequences of this dLAN-disturbed immune balance on the ability of the immune system to cope with other challenges should by clarified in further studies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Okuliarova, Mazgutova, Majzunova, Rumanova and Zeman.)

Autonomic nervous system (ANS) activity and imbalance between its sympathetic and parasympathetic components are important factors contributing to the initiation and progression of many cardiovascular disorders related to obesity. The results on respiratory sinus arrhythmia (RSA) magnitude changes as a parasympathetic index were not straightforward in previous studies on young obese subjects. Considering the potentially unbalanced ANS regulation with impaired parasympathetic control in obese patients, the aim of this study was to compare the relative contribution of baroreflex and non-baroreflex (central) mechanisms to the origin of RSA in obese vs. control subjects. To this end, we applied a recently proposed information-theoretic methodology - partial information decomposition (PID) - to the time series of heart rate variability (HRV, computed from RR intervals in the ECG), systolic blood pressure (SBP) variability, and respiration (RESP) pattern measured in 29 obese and 29 age- and gender-matched non-obese adolescents and young adults monitored in the resting supine position and during postural and cognitive stress evoked by head-up tilt and mental arithmetic. PID was used to quantify the so-called unique information transferred from RESP to HRV and from SBP to HRV, reflecting, respectively, non-baroreflex and RESP-unrelated baroreflex HRV mechanisms, and the redundant information transferred from (RESP, SBP) to HRV, reflecting RESP-related baroreflex RSA mechanisms. Our results suggest that obesity is associated: (i) with blunted involvement of non-baroreflex RSA mechanisms, documented by the lower unique information transferred from RESP to HRV at rest; and (ii) with a reduced response to postural stress (but not to mental stress), documented by the lack of changes in the unique information transferred from RESP and SBP to HRV in obese subjects moving from supine to upright, and by a decreased redundant information transfer in obese compared to controls in the upright position. These findings were observed in the presence of an unchanged RSA magnitude measured as the high frequency (HF) power of HRV, thus suggesting that the changes in ANS imbalance related to obesity in adolescents and young adults are subtle and can be revealed by dissecting RSA mechanisms into its components during various challenges., (Copyright © 2020 Javorka, Krohova, Czippelova, Turianikova, Mazgutova, Wiszt, Ciljakova, Cernochova, Pernice, Busacca and Faes.)

Heart rate variability (HRV; variability of the RR interval of the electrocardiogram) results from the activity of several coexisting control mechanisms, which involve the influence of respiration (RESP) and systolic blood pressure (SBP) oscillations operating across multiple temporal scales and changing in different physiological states. In this study, multiscale information decomposition is used to dissect the physiological mechanisms related to the genesis of HRV in 78 young volunteers monitored at rest and during postural and mental stress evoked by head-up tilt (HUT) and mental arithmetics (MA). After representing RR, RESP and SBP at different time scales through a recently proposed method based on multivariate state space models, the joint information transfer T RESP , SBP → RR is decomposed into unique, redundant and synergistic components, describing the strength of baroreflex modulation independent of respiration ( U SBP → RR ), nonbaroreflex ( U RESP → RR ) and baroreflex-mediated ( R RESP , SBP → RR ) respiratory influences, and simultaneous presence of baroreflex and nonbaroreflex respiratory influences ( S RESP , SBP → RR ), respectively. We find that fast (short time scale) HRV oscillations-respiratory sinus arrhythmia-originate from the coexistence of baroreflex and nonbaroreflex (central) mechanisms at rest, with a stronger baroreflex involvement during HUT. Focusing on slower HRV oscillations, the baroreflex origin is dominant and MA leads to its higher involvement. Respiration influences independent on baroreflex are present at long time scales, and are enhanced during HUT.