Baroreflex Dysfunction

Recovery of the baroreflex and autonomic modulation after anesthesia with MS-222 in bullfrogs

The time course for recovery after anesthesia is poorly described for tricaine methanesulfonate (MS-222). We suggest that the baroreflex and the heart rate variability (HRV) could be used to index the recovery of the autonomic modulation after anesthesia. We analyzed the recovery profile of behavioral and physiological parameters over time to analyze the progression of recovery after anesthesia of American bullfrogs with MS-222. Mean heart rate stabilized after 17 h, whereas the baroreflex efficiency index took 23 h and the baroreflex operating gain, 29 h. Mean arterial pressure recovered after 26 h. Power spectral density peaked at 23 h and again after 40 h. Baroreflex was a relevant component of the first phase of HRV, while autonomic modulation for resting may take longer than 40 h. We suggest that physiological recovery is a complex phenomenon with multiple progressive phases, and the baroreflex may be a useful tool to observe the first substantial recovery of post-instrumentation capacity for autonomic modulation.

Nocturia and frailty in older adults: a scoping review

BACKGROUND

More than one in two older people wake up several times a night to urinate. Far from being a minor inconvenience, nocturia is associated with poor health outcomes. Given the importance of sleep as a foundation for resilience and healthy ageing, nocturia may promote the development of frailty, which is inextricably linked to physical decline, disability, and mortality. The aim of this scoping review was to collate published evidence on the relationship between nocturia and frailty, using the methodological framework of Arksey and O'Malley, together with the Joanna Briggs Institute methodology as guidance (OSF registration: osf.io/d5ct7).

METHODS

Relevant publications were retrieved via PubMed, Embase, the Cochrane Library and Google Scholar. The Rayyan tool was used to facilitate the screening process. Data were extracted by two independent reviewers. 250 publications were initially identified, of which 87 met the eligibility criteria.

RESULTS

Most of the evidence came from cross-sectional studies, most of which had been published within the last 5 years. The researchers were diverse, with 27% having a geriatric background. Only few publications established a clear association between nocturia and frailty. Other topics included: the association between nocturia and poor sleep quality and duration; the association between sleep and frailty; the association between frailty, multimorbidity, and age-related changes in the lower urinary tract.

CONCLUSION

The findings emphasize the increasing interest and interdisciplinary nature of research into the relationship between frailty, nocturia, lower urinary tract symptoms, and sleep disturbances. Further research is required to enhance understanding, establish causality, and identify potential therapeutic approaches.

Cardiovascular autonomic dysfunction in post-COVID-19 syndrome: a major health-care burden

Cardiovascular autonomic dysfunction (CVAD) is a malfunction of the cardiovascular system caused by deranged autonomic control of circulatory homeostasis. CVAD is an important component of post-COVID-19 syndrome, also termed long COVID, and might affect one-third of highly symptomatic patients with COVID-19. The effects of CVAD can be seen at both the whole-body level, with impairment of heart rate and blood pressure control, and in specific body regions, typically manifesting as microvascular dysfunction. Many severely affected patients with long COVID meet the diagnostic criteria for two common presentations of CVAD: postural orthostatic tachycardia syndrome and inappropriate sinus tachycardia. CVAD can also manifest as disorders associated with hypotension, such as orthostatic or postprandial hypotension, and recurrent reflex syncope. Advances in research, accelerated by the COVID-19 pandemic, have identified new potential pathophysiological mechanisms, diagnostic methods and therapeutic targets in CVAD. For clinicians who daily see patients with CVAD, knowledge of its symptomatology, detection and appropriate management is more important than ever. In this Review, we define CVAD and its major forms that are encountered in post-COVID-19 syndrome, describe possible CVAD aetiologies, and discuss how CVAD, as a component of post-COVID-19 syndrome, can be diagnosed and managed. Moreover, we outline directions for future research to discover more efficient ways to cope with this prevalent and long-lasting condition.

Effects of Postural Resonance on Skin Sympathetic Nerve Activity and Blood Pressure: A Pilot Study Evaluating Vascular Tone Baroreflex Stimulation Through Biofeedback

Heart rate and vascular tension baroreflex exhibit resonance characteristics at approximately 0.1 and 0.03 Hz. In this study, we aimed to induce postural resonance (PR) through rhythmic postural adjustments. To assess the viability of this technique, we investigated the acute impacts of postural resonance on blood pressure, sympathetic nerve activity, and mood. Fifteen healthy study participants, consisting of 8 males and 7 females, were selected for this self-controlled study. Skin sympathetic nerve activity was continuously monitored during both the intervention and stress test on the experimental day. After PR intervention, the diastolic blood pressure and mean arterial pressure in the PR group exhibited significant reductions compared to the CON group (P = 0.032, CON = 71.67 ± 2.348, PR = 64.08 ± 2.35; P = 0.041, CON = 75.00 ± 2.17, PR = 81.67 ± 2.17). After PR intervention both left brachial ankle pulse wave velocity and right brachial ankle pulse wave velocity exhibited a significant reduction compared to pre-intervention levels (from 1115.86 ± 150.08 to 1048.43 ± 127.40 cm/s, p < 0.001; 1103.86 ± 144.35 to 1060.43 ± 121.35 cm/s, p = 0.018). PR intervention also led to a significant decrease in burst frequency and duration (P = 0.049; CON = 8.96 ± 1.17, PR = 5.51 ± 1.17) and a noteworthy decrease in burst amplitude and burst threshold during the cold-pressor test (P = 0.002; P = 0.002). Additionally, VAS scores exhibited a substantial increase following PR (P = 0.035, CON = 28.4 ± 4.49, PR = 42.17 ± 4.10). PR can induce resonance effects within the cardiovascular system, resulting in the effective reduction of blood pressure, skin sympathetic nerve activity and pulse wave velocity, and decreased burst amplitude and burst threshold of the sympathetic nerve during the cold-pressor test.

Associations between Total Atherosclerosis Burden of Baroreceptor-Resident Arteries and ECG Abnormalities after Acute Ischemic Stroke

Electrocardiogram (ECG) abnormalities are the most common cardiac complications after acute ischemic stroke (AIS) and predict poor outcomes. The arterial baroreflex is an essential determinant of cardiovascular autonomic regulation, with receptors mainly residing in carotid sinuses and aortic arch. The atherosclerosis of these baroreceptor-resident arteries (BRA) is very common in AIS patients and might impair baroreflex function. However, the associations between the atherosclerosis of BRA and ECG abnormalities after AIS are still unknown. In total, 228 AIS patients within 7 days after onset without a pre-existing heart disease were prospectively recruited. With computed tomography angiography, atherosclerosis conditions in 10 segments of the carotid sinuses and aortic arch were scored and summed as the Total Atherosclerosis Burden of BRA (TAB-BRA), and asymptomatic coronary artery stenosis (ACAS) ≥50% was simultaneously assessed. We performed 12-lead ECG to dynamically detect abnormal repolarization, and 24 h Holter ECG to monitor arrhythmias and heart rate variability (HRV) parameters, which are reliable indicators to assess cardiac autonomic function. We found that TAB-BRA was positively associated with abnormal repolarization (OR 1.09; CI% 1.03-1.16; p = 0.003) and serious cardiac arrhythmias (OR 1.08; CI% 1.01-1.15; p = 0.021). In addition, TAB-BRA was an important predictor of abnormal repolarization, persisting over 3 days (OR 1.17; CI% 1.05-1.30; p = 0.003). However, ACAS ≥ 50% did not relate to these ECG abnormalities. TAB-BRA was negatively correlated with parasympathetic-related HRV parameters. Our results indicated that AIS patients with a high TAB-BRA are more likely to have ECG abnormalities and delayed normalization, which may relate to the decreased cardiac parasympathetic activity, but not the accompanied ACAS ≥ 50%.

Role of splanchnic circulation in the pathogenesis of heart failure: State-of-the-art review

A hallmark of heart failure (HF), whether it presents itself during rest or periods of physical exertion, is the excessive elevation of intracardiac filling pressures at rest or with exercise. Many mechanisms contribute to the elevated intracardiac filling pressures, and notably, the concept of volume redistribution has gained attention as a cause of the elevated intracardiac filling pressures in patients with HF, particularly HF with preserved ejection fraction, who often present without symptoms at rest, with shortness of breath and fatigue appearing only during exertion. This phenomenon suggests cardiopulmonary system non-compliance and inappropriate volume distribution between the stressed and unstressed blood volume components. A substantial proportion of the intravascular blood volume is in the splanchnic vascular compartment in the abdomen. Preclinical and clinical investigations support the critical role of the sympathetic nervous system in modulating the capacitance and compliance of the splanchnic vascular bed via modulation of the greater splanchnic nerve (GSN). The GSN activation by stressors such as exercise causes excessive splanchnic vasoconstriction, which may contribute to the decompensation of chronic HF via volume redistribution from the splanchnic vascular bed to the central compartment. Accordingly, for example, GSN ablation for volume management has been proposed as a potential therapeutic intervention to increase unstressed blood volume. Here we provide a comprehensive review of the role of splanchnic circulation in the pathogenesis of HF and potential novel treatment options for redistributing blood volume to improve symptoms and prognosis in patients with HF.

Effects of robotic rehabilitation using the Erigo® device on patients with neurological injury: a systematic review and meta-analysis of randomized clinical trials

OBJECTIVE

To systematically review the effects of robotic rehabilitation with the Erigo® device on patients with neurological injury on safety, spasticity, muscle strength, functionality, gait/balance, and changes in the level of consciousness.

METHODS

MEDLINE, SciELO, EMBASE, The Cochrane Library - CENTRAL and PEDro databases were consulted without the restriction of date and language. Randomized controlled trials that evaluated the robotic rehabilitation and compared it to conventional or placebo therapy, isolated or in association with other therapy, were selected. Studies in which the treatment time was less than 10 sessions were excluded. The risk of bias was assessed with the use of the RoB 2.0 tool.

RESULTS

Nine studies were included, totaling 347 patients. The robotic rehabilitation performed by the Erigo® device proved to be safe for neurological patients. The meta-analysis showed an improvement for spasticity (MD = 0.29; 95% CI = -0.49 to -0.08; I2 = 0%), but there was no significant increase in muscle strength in patients with stroke (MD = 0.25; CI 95% = -0.22 to -0,71; I2 = 0%). Erigo® showed inconclusive effects on functionality, gait/balance and level of consciousness in patients with severe acquired brain injury and vegetative or minimally conscious state. All studies present some concerns for the risk of bias.

CONCLUSION

Erigo® as a robotic rehabilitation strategy is safe for patients with acquired brain injury and appears to reduce spasticity in patients with stroke. The effects on muscle strength, functionality, gait and balance and level of consciousness remain uncertain and the methodological quality of the clinical trials included in this review is limited.

Autoimmunity in Syndromes of Orthostatic Intolerance: An Updated Review

Orthostatic intolerance is a broad term that represents a spectrum of dysautonomic disorders, including postural orthostatic tachycardia syndrome (POTS) and orthostatic hypotension (OH), as manifestations of severe autonomic failure. While the etiology of orthostatic intolerance has not yet fully been uncovered, it has been associated with multiple underlying pathological processes, including peripheral neuropathy, altered renin-aldosterone levels, hypovolemia, and autoimmune processes. Studies have implicated adrenergic, cholinergic, and angiotensin II type I autoantibodies in the pathogenesis of orthostatic intolerance. Several case series have demonstrated that immunomodulation therapy resulted in favorable outcomes, improving autonomic symptoms in POTS and OH. In this review, we highlight the contemporary literature detailing the association of autoimmunity with POTS and OH.

The Prevalence of Orthostatic Hypotension in Cancer Patients

BACKGROUND

Orthostatic hypotension (OH) is associated with a higher risk of mortality in the general population; however, it has not been studied in the cancer population. This study aimed to assess the prevalence of OH in cancer patients compared to that in the noncancer population.

METHODS

A total of 411 patients (mean age 63.5 ± 10.6 years) were recruited: patients with active cancer (n = 223) and patients hospitalised for other reasons, but without a cancer diagnosis (n = 188). Medical histories were collected and an orthostatic challenge test was performed. OH was defined as a blood pressure (BP) decrease upon standing of ≥20 mmHg for the systolic or ≥10 mmHg for the diastolic BP after 1 or 3 min; or a systolic BP decrease <90 mmHg.

RESULTS

The prevalence of OH in the subjects with cancer was significantly higher than in the subjects without cancer (28.7% vs. 16.5%, respectively, p = 0.003). OH was the most common in the lung cancer patients (57.5%). In a single-variable analysis, the predictors of OH were cancer presence, age ≥ 65 years, and body mass index (BMI) ≥ 30 kg/m2. In the multivariable model, the strongest independent predictor of OH was cancer status, which doubled the risk of OH, and BMI ≥ 30 kg/m2 and diabetes.

CONCLUSIONS

Cancer patients are characterised by a high prevalence of OH. In this population, the recommendation of routine orthostatic challenge tests should be considered.

Adult vasovagal syncope with abdominal pain diagnosed by head-up tilt combined with transcranial doppler: a preliminary study

BACKGROUND

Syncope is a common condition that increases the risk of injury and reduces the quality of life. Abdominal pain as a precursor to vasovagal syncope (VVS) in adults is rarely reported and is often misdiagnosed.​.

METHODS

We present three adult patients with VVS and presyncopal abdominal pain diagnosed by synchronous multimodal detection (transcranial Doppler [TCD] with head-up tilt [HUT]) and discuss the relevant literature.

RESULTS

Case 1: A 52-year-old man presented with recurrent decreased consciousness preceded by six months of abdominal pain. Physical examinations were unremarkable. Dynamic electrocardiography, echocardiography, head and neck computed tomography angiography, magnetic resonance imaging (MRI), and video electroencephalogram showed no abnormalities. Case 2: A 57-year-old woman presented with recurrent syncope for 30 + years, accompanied by abdominal pain. Physical examination, electroencephalography, and MRI showed no abnormalities. Echocardiography showed large right-to-left shunts. Case 3: A 30-year-old woman presented with recurrent syncope for 10 + years, with abdominal pain as a precursor. Physical examination, laboratory analysis, head computed tomography, electrocardiography, and echocardiography showed no abnormalities. Syncope secondary to abdominal pain was reproduced during HUT. Further, HUT revealed vasovagal syncope, and synchronous TCD showed decreased cerebral blood flow; the final diagnosis was VVS in all cases.

CONCLUSIONS

Abdominal pain may be a precursor of VVS in adults, and our findings enrich the clinical phenotypic spectrum of VVS. Prompt recognition of syncopal precursors is important to prevent incidents and assist in treatment decision-making. Abdominal pain in VVS may be a sign of sympathetic overdrive. Synchronous multimodal detection can help in diagnosing VVS and understanding hemodynamic mechanisms.

Short communication: Baroreflex function in embryonic emus (Dromiceius novaehollandiae)

The baroreflex involves cardiovascular homeostatic mechanisms that buffer the system against acute deviations in arterial blood pressure. It is comprised of the cardiac limb which involves adjustments in heart rate and the peripheral limb which involves adjustments in vascular resistance. This negative feedback loop mechanism has been investigated in numerous species of adult vertebrates, however our understanding of the maturation and functional importance of the reflex in developing animals remains poorly understood. In egglaying species, our knowledge of this mechanism is limited to the domestic chicken embryo and the embryonic alligator. While each of these species possess a cardiac baroreflex prior to hatching, they differ in the timing when it becomes functional, with the embryonic chicken possessing the reflex at 90% of incubation, while the alligator possesses the reflex at 70% of incubation. In an effort to determine if bird species might share similar patterns of active baroreflex function, we studied embryonic emus (Dromiceius novaehollandiae). However, we hypothesized that emus would possess a pattern of baroreflex function similar to that of the American alligator given the emu embryo possesses functional vagal tone at 70% of incubation, possibly indicating a more mature collection of cardiovascular control mechanism than those found in embryonic chickens. Our findings illustrate that emu embryos possess a hypotensive baroreflex at 90% of incubation. Therefore, our data fail to support our original hypothesis. While only two species of birds have been studied in this context, it could indicate that baroreflex function is not essential for cardiovascular homeostasis in birds for the majority of in ovo development.

Contribution of platelets to disruption of the blood-brain barrier during arterial baroreflex dysfunction

BACKGROUND

Arterial baroreflex dysfunction, like many other central nervous system disorders, involves disruption of the blood-brain barrier, but what causes such disruption in ABR dysfunction is unclear. Here we explored the potential role of platelets in this disruption.

METHODS

ABR dysfunction was induced in rats using sinoaortic denervation, and the effects on integrity of the blood-brain barrier were explored based on leakage of Evans blue or FITC-dextran, while the effects on expression of CD40L in platelets and of key proteins in microvascular endothelial cells were explored using immunohistochemistry, western blotting and enzyme-linked immunosorbent assay. Similar experiments were carried out in rat brain microvascular endothelial cell line, which we exposed to platelets taken from rats with ABR dysfunction.

RESULTS

Sinoaortic denervation permeabilized the blood-brain barrier and downregulated zonula occludens-1 and occludin in rat brain, while upregulating expression of CD40L on the surface of platelets and stimulating platelet aggregation. Similar effects of permeabilization and downregulation were observed in healthy rats that received platelets from animals with ABR dysfunction, and in rat brain microvascular endothelial cells, but only in the presence of lipopolysaccharide. These effects were associated with activation of NF-κB signaling and upregulation of matrix metalloprotease-9. These effects of platelets from animals with ABR dysfunction were partially blocked by neutralizing antibody against CD40L or the platelet inhibitor clopidogrel.

CONCLUSION

During ABR dysfunction, platelets may disrupt the blood-brain barrier when CD40L on their surface activates NF-kB signaling within cerebral microvascular endothelial cells, leading to upregulation of matrix metalloprotease-9. Our findings imply that targeting CD40L may be effective against cerebral diseases involving ABR dysfunction.

ECHOCARDIOGRAPHY IN THIRTY AMERICAN FLAMINGOS (PHOENICOPTERUS RUBER) AND A CASE OF SUSPECTED NEURALLY MEDIATED REFLEX SYNCOPE

Heart disease in birds contributes to premature death and is usually detected postmortem. Echocardiography is a sensitive and noninvasive diagnostic modality but reported standard values for many species of birds, including American flamingos (Phoenicopterus ruber), are unavailable. Echocardiography was opportunistically performed on 30 unsedated American flamingos during their annual routine health examination. Structural heart disease was not found in any of the examined birds. However, 18 birds showed varying degrees of dynamic intraventricular obstruction. Echocardiographic parameters are reported. Benign neurocardiogenic weakness or syncopal events during handling were suspected in three birds. Stress combined with an intraventricular obstruction is believed to have triggered a cascade of parasympathetic innervation and sympathetic inhibition, similar to neurally mediated reflex syncope in humans.

Orthostatic Hypotension in Adults With Hypertension: A Scientific Statement From the American Heart Association

Although orthostatic hypotension (OH) has long been recognized as a manifestation of autonomic dysfunction, a growing body of literature has identified OH as a common comorbidity of hypertension. This connection is complex, related to pathophysiology in blood pressure regulation and the manner by which OH is derived as the difference between 2 blood pressure measurements. While traditional therapeutic approaches to OH among patients with neurodegenerative disorders focus on increasing upright blood pressure to prevent cerebral hypoperfusion, the management of OH among patients with hypertension is more nuanced; resting hypertension is itself associated with adverse outcomes among these patients. Although there is substantial evidence that intensive blood pressure treatment does not cause OH in the majority of patients with essential hypertension, some classes of antihypertensive agents may unmask OH in patients with an underlying autonomic impairment. Practical steps to manage OH among adults with hypertension start with (1) a thorough characterization of its patterns, triggers, and cause; (2) review and removal of aggravating factors (often pharmacological agents not related to hypertension treatment); (3) optimization of an antihypertensive regimen; and (4) adoption of a tailored treatment strategy that avoids exacerbating hypertension. These strategies include countermaneuvers and short-acting vasoactive agents (midodrine, droxidopa). Ultimately, further research is needed on the epidemiology of OH, the impact of hypertension treatment on OH, approaches to the screening and diagnosis of OH, and OH treatment among adults with hypertension to improve the care of these patients and their complex blood pressure pathophysiology.

Blood pressure fragmentation as a new measure of blood pressure variability: association with predictors of cardiac surgery outcomes

Background: Fluctuations in beat-to-beat blood pressure variability (BPV) encode untapped information of clinical utility. A need exists for developing new methods to quantify the dynamical properties of these fluctuations beyond their mean and variance. Objectives: Introduction of a new beat-to-beat BPV measure, termed blood pressure fragmentation (BPF), and testing of whether increased preoperative BPF is associated with (i) older age; (ii) higher cardiac surgical risk, assessed using the Society of Thoracic Surgeons' (STS) Risk of Morbidity and Mortality index and the European System for Cardiac Operative Risk Evaluation Score (EuroSCORE II); and (iii) longer ICU length of stay (LOS) following cardiac surgery. The secondary objective was to use standard BPV measures, specifically, mean, SD, coefficient of variation (CV), average real variability (ARV), as well a short-term scaling index, the detrended fluctuation analysis (DFA) ⍺1 exponent, in the same type of analyses to compare the results with those obtained using BPF. Methods: Consecutive sample of 497 adult patients (72% male; age, median [inter-quartile range]: 67 [59-75] years) undergoing cardiac surgery with cardiopulmonary bypass. Fragmentation, standard BPV and DFA ⍺1 measures were derived from preoperative systolic blood pressure (SBP) time series obtained from radial artery recordings. Results: Increased preoperative systolic BPF was associated with older age, higher STS Risk of Morbidity and Mortality and EuroSCORE II values, and longer ICU LOS in all models. Specifically, a one-SD increase in systolic BPF (9%) was associated with a 26% (13%-40%) higher likelihood of longer ICU LOS (>2 days). Among the other measures, only ARV and DFA ⍺1 tended to be associated with longer ICU LOS. However, the associations did not reach significance in the most adjusted models. Conclusion: Preoperative BPF was significantly associated with preoperative predictors of cardiac surgical outcomes as well as with ICU LOS. Our findings encourage future studies of preoperative BPF for assessment of health status and risk stratification of surgical and non-surgical patients.

Effect of levodopa on postural blood pressure changes in Parkinson disease: a randomized crossover study

PURPOSE

We investigated the effect of levodopa on postural blood pressure changes in individuals with Parkinson disease (PD) with (PD+OH) and without neurogenic OH (PD-OH).

METHODS

We performed a prospective randomized crossover study with autonomic testing performed ON and OFF levodopa. The primary outcome was the change in systolic blood pressure (SBP) from supine to 70° tilt at 3 min (ΔSBP-3'). Secondary outcomes included indices of baroreflex function and blood pressure and heart rate during tilt.

RESULTS

We enrolled 40 individuals with PD (21 PD+OH, 19 PD-OH), mean age (SD) 73.2 years (7.9), 13 women (32.5%)). There was no difference in age, sex, disease duration, and severity between PD+OH and PD-OH. Mean difference in ΔSBP-3' ON versus OFF levodopa in the whole study population was - 3.20 mmHg [- 7.36 to 0.96] (p = 0.14). Mean difference in ΔSBP-3' was - 2.14 mmHg [- 7.55 to 3.28] (p = 0.45) in PD+OH and - 5.14 mmHg [- 11.63 to 1.35] (p = 0.14) in PD-OH. Mean difference in ΔSBP ON versus OFF levodopa was greater at 7 and 10 min (- 7.52 mmHg [- 11.89 to - 3.15], p = 0.002, and - 7.82 mmHg [- 14.02 to - 1.67], p = 0.02 respectively). Levodopa was associated with lower absolute values of blood pressure in both PD+OH and PD-OH and cardiovascular noradrenergic baroreflex impairment.

CONCLUSION

Levodopa decreases blood pressure in both PD with and without autonomic failure, but it does not cause a greater fall in blood pressure from supine to standing at 3 min. Levodopa-induced baroreflex sympathetic noradrenergic impairment may contribute to lower blood pressure. Lower standing blood pressure with levodopa may increase the risks of fall and syncope.

A retrospective analysis of neurogenic orthostatic hypotension in long-term care facility residents with recurrent falls

INTRODUCTION

Approximately 50 % of residents in long-term care facilities fall yearly and orthostatic hypotension accounts for a significant portion of them. Neurogenic orthostatic hypotension - a subtype of orthostatic hypotension - is important to be recognized as its management is far more complex; undertreatment of these older adults can lead to recurrent falls, high healthcare cost burden, and increased morbidity and mortality. The primary purpose of our study was to describe the rate of neurogenic orthostatic hypotension in older adults in a long-term care facility, with a secondary purpose to describe risk factors for neurogenic orthostatic hypotension in this population.

METHODS

We conducted a retrospective case-control study of residents with recurrent falls at the Dayton Veteran's Affairs long-term care facility. Charts were manually reviewed. Inclusion criterion was three or more falls and age 65 or greater; we did not have exclusion criteria. ICD10 codes and most recent primary care physician notes were used to identify comorbidity diagnoses. Recent orthostatic vitals were used to assess orthostatic hypotension or neurogenic orthostatic hypotension diagnoses.

RESULTS

Of our sample of 224 residents, we observed a prevalence of 20.5 % for neurogenic orthostatic hypotension and 32.1 % for orthostatic hypotension. Neither of them had diagnosis of neurogenic orthostatic hypotension documented. Parkinson's disease was associated with neurogenic orthostatic hypotension (OR-4.3; p = 0.002). Hypertension was prevalent in 69.6 % of residents with orthostatic vitals suggestive of neurogenic orthostatic hypotension.

CONCLUSION

Older adults with recurrent falls at a long-term care facility meet criteria for neurogenic orthostatic hypotension diagnosis far more often than is documented. Common comorbidities associated with neurogenic orthostatic hypotension in this population include Parkinson's disease.

Vestibular syncope

PURPOSE OF REVIEW

This review considers recent observations on vestibular syncope in terms of clinical features, laboratory findings, and potential mechanisms.

RECENT FINDINGS

Vestibular syncope, potentially associated with severe fall-related injuries, may develop multiple times in about one-third of patients. Meniere's disease and benign paroxysmal positional vertigo are the most common causes of vestibular syncope, but the underlying disorders remain elusive in 62% of cases with vestibular syncope. The postictal orthostatic blood pressure test exhibits a lower diagnostic yield. Vestibular function tests, such as cervical vestibular-evoked myogenic potentials and video head impulse tests, can reveal one or more abnormal findings, suggesting compensated or ongoing minor vestibular dysfunctions. The pathomechanism of syncope is assumed to be the erroneous interaction between the vestibulo-sympathetic reflex and the baroreflex that have different operating mechanisms and action latencies. The central vestibular system, which estimates gravity orientation and inertia motion may also play an important role in abnormal vestibulo-sympathetic reflex.

SUMMARY

Vestibular disorders elicit erroneous cardiovascular responses by providing false vestibular information. The results include vertigo-induced hypertension or hypotension, which can ultimately lead to syncope in susceptible patients.

Concentration-effect relationships of plasma caffeine on EEG delta power and cardiac autonomic activity during human sleep

Acute caffeine intake affects brain and cardiovascular physiology, yet the concentration-effect relationships on the electroencephalogram and cardiac autonomic activity during sleep are poorly understood. To tackle this question, we simultaneously quantified the plasma caffeine concentration with ultra-high-performance liquid chromatography, as well as the electroencephalogram, heart rate and high-frequency (0.15-0.4 Hz) spectral power in heart rate variability, representing parasympathetic activity, with standard polysomnography during undisturbed human sleep. Twenty-one healthy young men in randomized, double-blind, crossover fashion, ingested 160 mg caffeine or placebo in a delayed, pulsatile-release caffeine formula at their habitual bedtime, and initiated a 4-hr sleep opportunity 4.5 hr later. The mean caffeine levels during sleep exhibited high individual variability between 0.2 and 18.4 μmol L-1 . Across the first two non-rapid-eye-movement (NREM)-rapid-eye-movement sleep cycles, electroencephalogram delta (0.75-2.5 Hz) activity and heart rate were reliably modulated by waking and sleep states. Caffeine dose-dependently reduced delta activity and heart rate, and increased high-frequency heart rate variability in NREM sleep when compared with placebo. The average reduction in heart rate equalled 3.24 ± 0.77 beats per minute. Non-linear statistical models suggest that caffeine levels above ~7.4 μmol L-1 decreased electroencephalogram delta activity, whereas concentrations above ~4.3 μmol L-1 and ~ 4.9 μmol L-1 , respectively, reduced heart rate and increased high-frequency heart rate variability. These findings provide quantitative concentration-effect relationships of caffeine, electroencephalogram delta power and cardiac autonomic activity, and suggest increased parasympathetic activity during sleep after intake of caffeine.

CVRanalysis: a free software for analyzing cardiac, vascular and respiratory interactions

Introduction: Simultaneous beat-to-beat R-R intervals, blood pressure and respiration signals are routinely analyzed for the evaluation of autonomic cardiovascular and cardiorespiratory regulations for research or clinical purposes. The more recognized analyses are i) heart rate variability and cardiac coherence, which provides an evaluation of autonomic nervous system activity and more particularly parasympathetic and sympathetic autonomic arms; ii) blood pressure variability which is mainly linked to sympathetic modulation and myogenic vascular function; iii) baroreflex sensitivity; iv) time-frequency analyses to identify fast modifications of autonomic activity; and more recently, v) time and frequency domain Granger causality analyses were introduced for assessing bidirectional causal links between each considered signal, thus allowing the scrutiny of many physiological regulatory mechanisms. Methods: These analyses are commonly applied in various populations and conditions, including mortality and morbidity predictions, cardiac and respiratory rehabilitation, training and overtraining, diabetes, autonomic status of newborns, anesthesia, or neurophysiological studies. Results: We developed CVRanalysis, a free software to analyze cardiac, vascular and respiratory interactions, with a friendly graphical interface designed to meet laboratory requirements. The main strength of CVRanalysis resides in its wide scope of applications: recordings can arise from beat-to-beat preprocessed data (R-R, systolic, diastolic and mean blood pressure, respiration) or raw data (ECG, continuous blood pressure and respiratory waveforms). It has several tools for beat detection and correction, as well as setting of specific areas or events. In addition to the wide possibility of analyses cited above, the interface is also designed for easy study of large cohorts, including batch mode signal processing to avoid running repetitive operations. Results are displayed as figures or saved in text files that are easily employable in statistical softwares. Conclusion: CVRanalysis is freely available at this website: anslabtools.univ-st-etienne.fr. It has been developed using MATLAB® and works on Windows 64-bit operating systems. The software is a standalone application avoiding to have programming skills and to install MATLAB. The aims of this paper area are to describe the physiological, research and clinical contexts of CVRanalysis, to introduce the methodological approach of the different techniques used, and to show an overview of the software with the aid of screenshots.

Emerging devices for heart failure management

There have been significant advances in the treatment of heart failure (HF) in recent years, driven by significant strides in guideline-directed medical therapy (GDMT). Despite this, HF is still associated with high levels of morbidity and mortality, and most patients do not receive optimal medical therapy. In conjunction with the improvement of GDMT, novel device therapies have been developed to better treat HF. These devices include technology capable of remotely monitoring HF physiology, devices that modulate the autonomic nervous system, and those that structurally change the heart with the ultimate aim of addressing the root causes of HF physiology As these device therapies gradually integrate into the fabric of HF patient care, it becomes increasingly important for modern cardiologists to become familiar with them. Hence, the objective of this review is to shed light on currently emerging devices for the treatment of HF.

Anatomy and physiology of the autonomic nervous system: Implication on the choice of diagnostic/monitoring tools in 2023

The autonomic nervous system (ANS) harmoniously regulates all internal organic functions (heart rate, blood pressure, vasomotion, digestive tract motility, endocrinal secretions) and adapts them to the needs. It's the control of so-called vegetative functions, which allows homeostasis but also allostasis of our body. ANS is divided into two systems often understood as antagonistic and complementary: the sympathetic and the parasympathetic systems. However, we currently know of many situations of co-activation of the two systems. Long seen as acting through "reflex" control loops passing through the integration of peripheral information and the efferent response to the peripheral organ, more recent electrophysiological and brain functional imaging knowledge has been able to identify the essential role of the central autonomic network. This element complicates the understanding of the responses of the reflex loops classically used to identify and quantify dysautonomia. Finding the "ANS" tools best suited for the clinician in their daily practice is a challenge that we will attempt to address in this work.

Higher Cardiovagal Baroreflex Sensitivity Predicts Increased Pain Outcomes After Cardiothoracic Surgery

Excessive postoperative pain can lead to extended hospitalization and increased expenses, but factors that predict its severity are still unclear. Baroreceptor function could influence postoperative pain by modulating nociceptive processing and vagal-mediated anti-inflammatory reflexes. To investigate this relationship, we conducted a study with 55 patients undergoing minimally invasive cardiothoracic surgery to evaluate whether cardiovagal baroreflex sensitivity (BRS) can predict postoperative pain. We assessed the spontaneous cardiovagal BRS under resting pain-free conditions before surgery. We estimated postoperative pain outcomes with the Pain, Enjoyment, and General Activity scale and pressure pain thresholds on the first (POD1) and second (POD2) postoperative days and persistent pain 3 and 6 months after hospital discharge. We also measured circulating levels of relevant inflammatory biomarkers (C-reactive protein, albumin, cytokines) at baseline, POD1, and POD2 to assess the contribution of inflammation to the relationship between BRS and postoperative pain. Our mixed-effects model analysis showed a significant main effect of preoperative BRS on postoperative pain (P = .013). Linear regression analysis revealed a significant positive association between preoperative BRS and postoperative pain on POD2, even after adjusting for demographic, surgical, analgesic treatment, and psychological factors. Moreover, preoperative BRS was linked to pain interfering with general activity and enjoyment but not with other pain parameters (pain intensity and pressure pain thresholds). Preoperative BRS had modest associations with postoperative C-reactive protein and IL-10 levels, but they did not mediate its relationship with postoperative pain. These findings indicate that preoperative BRS can independently predict postoperative pain, which could serve as a modifiable criterion for optimizing postoperative pain management. PERSPECTIVE: This article shows that preoperative BRS predicts postoperative pain outcomes independently of the inflammatory response and pain sensitivity to noxious pressure stimulation. These results provide valuable insights into the role of baroreceptors in pain and suggest a helpful tool for improving postoperative pain management.

Blood pressure variability, central autonomic network dysfunction and cerebral small vessel disease in APOE4 carriers

Background

Increased blood pressure variability (BPV) is a risk factor for cerebral small vessel disease (CSVD) and neurodegeneration, independent of age and average blood pressure, particularly in apolipoprotein E4 (APOE4) carriers. However, it remains uncertain whether BPV elevation is a cause or a consequence of vascular brain injury, or to what degree injury to the central autonomic network (CAN) may contribute to BPV-associated risk in APOE4 carriers.

Methods

Independently living older adults (n=70) with no history of stroke or dementia were recruited from the community and underwent 5 minutes of resting beat-to-beat blood pressure monitoring, genetic testing, and brain MRI. Resting BPV, APOE genotype, CSVD burden on brain MRI, and resting state CAN connectivity by fMRI were analyzed. Causal mediation and moderation analysis evaluated BPV and CAN effects on CSVD in APOE4 carriers (n=37) and non-carriers (n=33).

Results

Higher BPV was associated with the presence and extent of CSVD in APOE4 carriers, but not non-carriers, independent of CAN connectivity (B= 18.92, P= .02), and CAN connectivity did not mediate the relationship between BPV and CSVD. In APOE4 carriers, CAN connectivity moderated the relationship between BPV and CSVD, whereby BPV effects on CSVD were greater in those with lower CAN connectivity (B= 36.43, P= .02).

Conclusions

Older APOE4 carriers with higher beat-to-beat BPV exhibit more extensive CSVD, independent of average blood pressure, and the strength of CAN connectivity does not mediate these effects. Findings suggest increased BPV is more likely a cause, not a consequence, of CSVD. BPV is more strongly associated with CSVD in APOE4 carriers with lower rsCAN connectivity, suggesting CAN dysfunction and BPV elevation may have synergistic effects on CSVD. Further studies are warranted to understand the interplay between BPV and CAN function in APOE4 carriers.

Variability of cardioinhibition in vasovagal syncope: differences between subgroups during cardioinhibition and beyond

PURPOSE

We compared hemodynamic parameters between subjects with marked, intermediate and minimal cardioinhibition during vasovagal syncope.

METHODS

The study included subjects with a decrease in heart rate while experiencing a complete vasovagal syncope during tilt-table testing. The subjects were classified as having marked, intermediate or minimal cardioinhibition, based on tertile values of the decrease in heart rate. Hemodynamic parameters between these groups were compared before tilt in the supine position, shortly after tilt and during cardioinhibition.

RESULTS

A total of 149 subjects with a median age of 43 (interquartile range 24-60) years were included in the study. Among the three groups with different levels of cardioinhibition, the highest heart rate was observed in subjects with marked cardioinhibition both before and shortly after tilt and at the start of cardioinhibition. The heart rate decrease in these subjects was both larger and faster compared to subjects with minimal and intermediate cardioinhibition.

CONCLUSION

Subjects with marked cardioinhibition have both a larger and faster decrease in heart rate compared to subjects with intermediate and minimal cardioinhibition, as early as from the start of cardioinhibition. Marked cardioinhibition is related to differences in hemodynamic profiles already present well before the start of cardioinhibition.

Daily biofeedback to modulate heart rate oscillations affects structural volume in hippocampal subregions targeted by the locus coeruleus in older adults but not younger adults

Using data from a clinical trial, we tested the hypothesis that daily sessions modulating heart rate oscillations affect older adults' volume of a region-of-interest (ROI) comprised of adjacent hippocampal subregions with relatively strong locus coeruleus (LC) noradrenergic input. Younger and older adults were randomly assigned to one of two daily biofeedback practices for 5 weeks: (1) engage in slow-paced breathing to increase the amplitude of oscillations in heart rate at their breathing frequency (Osc+); (2) engage in self-selected strategies to decrease heart rate oscillations (Osc-). The interventions did not significantly affect younger adults' hippocampal volume. Among older adults, the two conditions affected volume in the LC-targeted hippocampal ROI differentially as reflected in a significant condition × time-point interaction on ROI volume. These condition differences were driven by opposing changes in the two conditions (increased volume in Osc+ and decreased volume in Osc-) and were mediated by the degree of heart rate oscillation during training sessions.

Effect of hypoglycemia on baroreflex sensitivity in individuals with type 2 diabetes: implications for autonomic control of cardiovascular function in diabetes

PURPOSE

Hypoglycemia is associated with increased mortality, though the mechanisms underlying this association are not established. Hypoglycemia impairs the counterregulatory hormonal and autonomic responses to subsequent hypoglycemia. It is unknown whether hypoglycemia elicits a generalized impairment in autonomic control of cardiovascular function in individuals with type 2 diabetes. We tested the hypothesis that in individuals with type 2 diabetes, hypoglycemia impairs a key measure of cardiovascular autonomic homeostasis, baroreflex sensitivity.

METHODS

Sixteen individuals with well-controlled type 2 diabetes and without known cardiovascular disease were exposed to two 90-min episodes of experimental hypoglycemia (2.8 mmol/L, 50 mg/dL) on the same day. All individuals experienced a hypoglycemic-hyperinsulinemic clamp in the morning (AM clamp) and again in the afternoon (PM clamp). Baroreflex sensitivity was assessed using the modified Oxford method before the initiation of each hypoglycemic-hyperinsulinemic clamp, during the last 30 min of hypoglycemia, and the following morning. A mixed effects model adjusting for sex, age, BMI, and insulin level, demonstrated a significant effect of hypoglycemia on baroreflex sensitivity. The study is registered at ClinicalTrials.gov (NCT03422471).

RESULTS

Baroreflex sensitivity during PM hypoglycemia was reduced compared to baseline, during AM hypoglycemia, and the next day. Insulin levels positively correlated with baroreflex sensitivity at baseline and during AM hypoglycemia.

CONCLUSION

Exposure to hypoglycemia impairs a key measure of autonomic control of cardiovascular function and, thus, may increase the risk of cardiac arrhythmias and blood pressure lability in individuals with type 2 diabetes. This effect is attenuated in part by increased insulin levels.

When the tap runs dry: the physiological effects of acute experimental dehydration in Peromyscus eremicus

Desert organisms have evolved physiological, biochemical and genomic mechanisms to survive the extreme aridity of desert environments. Studying desert-adapted species provides a unique opportunity to investigate the survival strategies employed by organisms in some of the harshest habitats on Earth. Two of the primary challenges faced in desert environments are maintaining water balance and thermoregulation. We collected data in a simulated desert environment and a captive colony of cactus mice (Peromyscus eremicus) and used lab-based experiments with real time physiological measurements; energy expenditure, water loss rate and respiratory exchange rate, to characterize the response to water deprivation. Mice without access to water had significantly lower energy expenditures and in turn, reduced water loss compared to mice with access to water after the first 24 h of the experiment. Additionally, we observed significant mass loss that is probably due to dehydration-associated anorexia a response to limit fluid loss by reducing waste and the solute load as well as allowing water reabsorption from the kidneys and gastrointestinal tract. Finally, we observed body temperature correlated with sex, with males without access to water maintaining body temperature when compared with hydrated males, whereas body temperature decreased for females without access to water, suggesting daily metabolic depression in females.

Dopamine alters phage morphology to exert an anti-infection effect

Antiviral drug development is important for human health, and the emergence of novel COVID-19 variants has seriously affected human lives and safety. A bacteriophage-a bacterial virus with a small and simple structure-is an ideal experimental candidate for studying the interactions between viruses and their hosts. In this study, the effects and mechanisms of catecholamines on phages were explored, and dopamine (DA) was found to have general and efficient anti-infection effects. A clear dose-dependent effect was observed when different phages were treated with DA, with higher DA concentrations exhibiting stronger anti-phage activity. The half maximal inhibitory concentration values of DA for vB-EcoS-IME167, T4 Phage, and VMY22 were determined as 0.26, 0.12, and 0.73 mg mL-1, respectively. The anti-phage effect of DA increased with treatment duration. In addition, the anti-infection activities of DA against vB-EcoS-IME167, T4 Phage, and VMY22 were increased by 105, 104, and 104 folds compared to that of the control. This ability of DA was observed only in phages and not in the host bacteria. Morphological changes of phages were observed under transmission electron microscopy following their treatment with DA, and considerable changes in adsorption were confirmed via quantitative reverse transcription polymerase chain reaction. These results suggest that the anti-phage effect of DA is primarily due to the destruction of the external structure of the phage. This study, to the best of our knowledge, is the first to report the universal anti-phage infection effect of dopamine, which provides novel information regarding DA and forms a basis for further research and development of antiviral drugs. Moreover, it provides a new perspective for the research about the defense and counter-defense of bacteria and bacteriophages.

Hemodynamic Effects of the Osmopressor Response: A Systematic Review and Meta-Analysis

Background Rapidly consuming water may offer practical orthostatic hypotension therapy. However, its efficacy across disorders remains uncertain. This study aims to assess the impact of rapid 350- to 500-mL water intake on systolic and diastolic blood pressure (BP) and heart rate (HR) through a systematic review and meta-analysis. Methods and Results We systematically reviewed MEDLINE and Embase up to June 2023, including randomized controlled trials and prospective cohort studies. Using random-effects meta-analysis, we calculated pooled mean differences (MDs) for maximum hemodynamic effects of rapid 350- to 500-mL water bolus consumption. Participants with orthostatic hypotension experienced increased systolic BP (MD, 24.18 [95% CI, 15.48-32.88]) and diastolic BP (MD, 11.98 [95% CI, 8.87-15.09]) with decreased HR (MD, -3.46 [95% CI, -5.21 to -1.71]). Similar results were observed in multiple system atrophy and pure autonomic failure subgroup analysis. Healthy participants showed modest increases in systolic BP (MD, 2.33 [95% CI, 1.02-3.64]) and diastolic BP (MD, 2.73 [95% CI, 1.15-4.30]), but HR changes were not significant (MD, -2.06 [95% CI, -5.25 to 1.13]). Water had no significant hemodynamic effects in patients with seated or supine postural tachycardia syndrome, although standing effects were unassessed. Our data do not exclude water's potential standing effect in postural tachycardia syndrome. Conclusions In patients with orthostatic hypotension, rapid water intake elevated short-term systolic BP and diastolic BP, with mild HR reduction when seated or supine. Healthy participants exhibited similar but milder effects. However, patients with postural tachycardia syndrome did not experience these changes in seated or supine positions. Further research is needed to evaluate the promising impact of rapid water ingestion on patients with postural tachycardia syndrome in a standing position, which was not addressed in our study.

Unraveling Autonomic Dysfunction in GBA-Related Parkinson's Disease

Background

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.

Objectives

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.

Methods

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.

Results

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.

Conclusions

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.

The contribution of the AT1 receptor to erythropoiesis

The renin-angiotensin system (RAS) comprises a broad set of functional peptides and receptors that play a role in cardiovascular homeostasis and contribute to cardiovascular pathologies. Angiotensin II (Ang II) is the most potent peptide hormone produced by the RAS due to its high abundance and its strong and pleiotropic impact on the cardiovascular system. Formation of Ang II takes place in the bloodstream and additionally in tissues in the so-called local RAS. Of the two Ang II receptors (AT1 and AT2) that Ang II binds to, AT1 is the most expressed throughout the mammalian body. AT1 expression is not restricted to cells of the cardiovascular system but in fact AT1 protein is found in nearly all organs, hence, Ang II takes part in several modulatory physiological processes one of which is erythropoiesis. In this review, we present multiple evidence supporting that Ang II modulates physiological and pathological erythropoiesis processes trough the AT1 receptor. Cumulative evidence indicates that Ang II by three distinct mechanisms influences erythropoiesis: 1) stimulation of renal erythropoietin synthesis; 2) direct action on bone marrow precursor cells; and 3) modulation of sympathetic nerve activity to the bone marrow. The text highlights clinical and preclinical evidence focusing on mechanistic studies using rodent models.

The Impact of the Nervous System on Arteries and the Heart: The Neuroimmune Cardiovascular Circuit Hypothesis

Three systemic biological systems, i.e., the nervous, the immune, and the cardiovascular systems, form a mutually responsive and forward-acting tissue network to regulate acute and chronic cardiovascular function in health and disease. Two sub-circuits within the cardiovascular system have been described, the artery brain circuit (ABC) and the heart brain circuit (HBC), forming a large cardiovascular brain circuit (CBC). Likewise, the nervous system consists of the peripheral nervous system and the central nervous system with their functional distinct sensory and effector arms. Moreover, the immune system with its constituents, i.e., the innate and the adaptive immune systems, interact with the CBC and the nervous system at multiple levels. As understanding the structure and inner workings of the CBC gains momentum, it becomes evident that further research into the CBC may lead to unprecedented classes of therapies to treat cardiovascular diseases as multiple new biologically active molecules are being discovered that likely affect cardiovascular disease progression. Here, we weigh the merits of integrating these recent observations in cardiovascular neurobiology into previous views of cardiovascular disease pathogeneses. These considerations lead us to propose the Neuroimmune Cardiovascular Circuit Hypothesis.

A Review on the Clinical Diagnosis of Multiple System Atrophy

Multiple system atrophy (MSA) is a rare, adult-onset, progressive neurodegenerative disorder with major diagnostic challenges. Aiming for a better diagnostic accuracy particularly at early disease stages, novel Movement Disorder Society criteria for the diagnosis of MSA (MDS MSA criteria) have been recently developed. They introduce a neuropathologically established MSA category and three levels of clinical diagnostic certainty including clinically established MSA, clinically probable MSA, and the research category of possible prodromal MSA. The diagnosis of clinically established and clinically probable MSA is based on the presence of cardiovascular or urological autonomic failure, parkinsonism (poorly L-Dopa-responsive for the diagnosis of clinically established MSA), and cerebellar syndrome. These core clinical features need to be associated with supportive motor and non-motor features (MSA red flags) and absence of any exclusion criteria. Characteristic brain MRI markers are required for a diagnosis of clinically established MSA. A research category of possible prodromal MSA is devised to capture patients manifesting with autonomic failure or REM sleep behavior disorder and only mild motor signs at the earliest disease stage. There is a number of promising laboratory markers for MSA that may help increase the overall clinical diagnostic accuracy. In this review, we will discuss the core and supportive clinical features for a diagnosis of MSA in light of the new MDS MSA criteria, which laboratory tools may assist in the clinical diagnosis and which major differential diagnostic challenges should be borne in mind.

Cooling Down Inflammation in the Cardiovascular System via the Nicotinic Acetylcholine Receptor

ABSTRACT

Inflammation is a major player in many cardiovascular diseases including hypertension, atherosclerosis, myocardial infarction, and heart failure. In many individuals, these conditions coexist and mutually exacerbate each other's progression. The pathophysiology of these diseases entails the active involvement of both innate and adaptive immune cells. Immune cells that possess the α7 subunit of the nicotinic acetylcholine receptor on their surface have the potential to be targeted through both pharmacological and electrical stimulation of the cholinergic system. The cholinergic system regulates the inflammatory response to various stressors in different organ systems by systematically suppressing spleen-derived monocytes and chemokines and locally improving immune cell function. Research on the cardiovascular system has demonstrated the potential for atheroma plaque stabilization and regression as favorable outcomes. Smaller infarct size and reduced fibrosis have been associated with improved cardiac function and a decrease in adverse cardiac remodeling. Furthermore, enhanced electrical stability of the myocardium can lead to a reduction in the incidence of ventricular tachyarrhythmia. In addition, improving mitochondrial dysfunction and decreasing oxidative stress can result in less myocardial tissue damage caused by reperfusion injury. Restoring baroreflex activity and reduction in renal damage can promote blood pressure regulation and help counteract hypertension. Thus, the present review highlights the potential of nicotinic acetylcholine receptor activation as a natural approach to alleviate the adverse consequences of inflammation in the cardiovascular system.

Daily biofeedback to modulate heart rate oscillations affects structural volume in hippocampal subregions targeted by the locus coeruleus in older adults but not younger adults

Using data from a clinical trial, we tested the hypothesis that daily sessions modulating heart rate oscillations affect older adults' volume of a region-of-interest (ROI) comprised of adjacent hippocampal subregions with relatively strong locus coeruleus (LC) noradrenergic input. Younger and older adults were randomly assigned to one of two daily biofeedback practices for 5 weeks: 1) engage in slow-paced breathing to increase the amplitude of oscillations in heart rate at their breathing frequency (Osc+); 2) engage in self-selected strategies to decrease heart rate oscillations (Osc-). The interventions did not significantly affect younger adults' hippocampal volume. Among older adults, the two conditions affected volume in the LC-targeted hippocampal ROI differentially as reflected in a significant condition x time-point interaction on ROI volume. These condition differences were driven by opposing changes in the two conditions (increased volume in Osc+ and decreased volume in Osc-) and were mediated by the degree of heart rate oscillation during training sessions.

Non-Pharmacological Treatment of Autonomic Dysfunction in Parkinson's Disease and Other Synucleinopathies

Symptoms of autonomic dysfunction are prevalent and can be very debilitating, reducing the quality of life in patients with Parkinson's disease (PD) and other synucleinopathies such as dementia with Lewy bodies and multiple system atrophy. Non-pharmacological therapies are key to effective management and are frequently used alone in patients with mild autonomic symptoms, or in combination with pharmacological therapies in patients with moderate and severe symptoms. This article focuses on non-pharmacological approaches. Our objective was to review the non-drug and non-surgical approaches to treating autonomic symptoms in patients with PD and other synucleinopathies, focusing on cardiovascular, gastrointestinal, and genitourinary autonomic dysfunction. Evidence supporting the effectiveness of non-pharmacological treatment for the management of neurogenic orthostatic hypotension, supine hypertension, constipation, and bladder and sexual dysfunction is available. High-quality prospective trials are scarce, yet some non-pharmacological interventions (e.g., physical counter maneuvers) can be evaluated relatively quickly on an individual basis and often seem effective. The emerging variety of clinical presentations advocates for a stepwise, individualized, and non-pharmacological approach for the management of autonomic symptoms. Often, the first step is to reduce or discontinue drugs that cause or aggravate autonomic symptoms followed by lifestyle measures. While non-pharmacological and non-surgical treatments are available and, in many cases, effective to improve symptoms of autonomic dysfunction in PD and other synucleinopathies, they are often overlooked. Large randomized trials testing and comparing non-pharmacological approaches are warranted.

Blood Pressure Changes in Association with Nimodipine Therapy in Patients with Spontaneous Subarachnoid Hemorrhage

BACKGROUND

Nimodipine is recommended to prevent delayed cerebral ischemia in patients with spontaneous subarachnoid hemorrhage (SAH). Here, we studied hemodynamic side effects of different nimodipine formulations (per os [PO] and intravenous [IV]) in patients with SAH undergoing continuous blood pressure monitoring.

METHODS

This observational cohort study includes consecutive patients with SAH (271 included in the IV group, 49 in the PO group) admitted to a tertiary care center between 2010 and 2021. All patients received prophylactic IV or PO nimodipine. Hemodynamic responses were evaluated based on median values within the first hour after continuous IV nimodipine initiation or PO nimodipine application (601 intakes within 15 days). Significant changes were defined as > 10% drop in systolic blood pressure (SBP) or diastolic blood pressure from baseline (median values 30 min before nimodipine application). With the use of multivariable logistic regression, risk factors associated with SBP drops were identified.

RESULTS

Patients were admitted with a median Hunt & Hess score of 3 (2-5; IV 3 [2-5], PO 1 [1-2], p < 0.001) and were 58 (49-69) years of age. Initiation of IV nimodipine was associated with a > 10% SBP drop in 30% (81/271) of patients, with a maximum effect after 15 min. A start or increase in noradrenaline was necessary in 136/271 (50%) patients, and colloids were administered in 25/271 (9%) patients within 1 h after IV nimodipine initiation. SBP drops > 10% occurred after 53/601 (9%) PO nimodipine intakes, with a maximum effect after 30-45 min in 28/49 (57%) patients. Noradrenaline application was uncommon (3% before and 4% after nimodipine PO intake). Hypotensive episodes to an SBP < 90 mm Hg were not observed after IV or PO nimodipine application. In multivariable analysis, only a higher SBP at baseline was associated with a > 10% drop in SBP after IV (p < 0.001) or PO (p = 0.001) nimodipine application, after adjusting for the Hunt & Hess score on admission, age, sex, mechanical ventilation, days after intensive care unit admission, and delayed cerebral ischemia.

CONCLUSIONS

Significant drops in SBP occur in one third of patients after the start of IV nimodipine and after every tenth PO intake. Early recognition and counteracting with vasopressors or fluids seems necessary to prevent hypotensive episodes.

Applying systems thinking to unravel the mechanisms underlying orthostatic hypotension related fall risk

Orthostatic hypotension (OH) is an established and common cardiovascular risk factor for falls. An in-depth understanding of the various interacting pathophysiological pathways contributing to OH-related falls is essential to guide improvements in diagnostic and treatment opportunities. We applied systems thinking to multidisciplinary map out causal mechanisms and risk factors. For this, we used group model building (GMB) to develop a causal loop diagram (CLD). The GMB was based on the input of experts from multiple domains related to OH and falls and all proposed mechanisms were supported by scientific literature. Our CLD is a conceptual representation of factors involved in OH-related falls, and their interrelatedness. Network analysis and feedback loops were applied to analyze and interpret the CLD, and quantitatively summarize the function and relative importance of the variables. Our CLD contains 50 variables distributed over three intrinsic domains (cerebral, cardiovascular, and musculoskeletal), and an extrinsic domain (e.g., medications). Between the variables, 181 connections and 65 feedback loops were identified. Decreased cerebral blood flow, low blood pressure, impaired baroreflex activity, and physical inactivity were identified as key factors involved in OH-related falls, based on their high centralities. Our CLD reflects the multifactorial pathophysiology of OH-related falls. It enables us to identify key elements, suggesting their potential for new diagnostic and treatment approaches in fall prevention. The interactive online CLD renders it suitable for both research and educational purposes and this CLD is the first step in the development of a computational model for simulating the effects of risk factors on falls.

Device Interventions for Heart Failure

Despite remarkable advances in drug therapy for heart failure (HF), the residual HF-related morbidity, mortality, and hospitalizations remain substantial across all HF phenotypes, and significant proportions of patients with HF remain symptomatic despite optimal drug therapy. Driven by these unmet clinical needs, the exponential growth of transcatheter interventions, and a recent shift in the regulatory landscape of device-based therapies, novel device-based interventions have emerged as a potential therapy for various phenotypes of HF. Device-based interventions can overcome some of the limitations of drug therapy (eg, intolerance, nonadherence, inconsistent delivery, and recurrent and long-term cost) and can target some HF-related pathophysiologic pathways more effectively than drug therapy. This paper reviews the current evolving landscape of device-based interventions in HF and highlights critical points related to implementation of these therapies in the current workflow of HF management.

Impact of thoracic endovascular aortic repair following blunt traumatic thoracic aortic injury on blood pressure

BACKGROUND

Blunt traumatic thoracic aortic injuries (BTAIs) are associated with a high mortality rate. Thoracic endovascular aortic repair (TEVAR) is the most frequently used surgical strategy in patients with BTAI, as it offers good short- and middle-term results. Previous studies have reported an abnormally high prevalence of hypertension (HT) in these patients. This work aimed to describe the long-term prevalence of HT and provide a comprehensive evaluation of the biomechanical, clinical, and functional factors involved in HT development.

METHODS

Twenty-six patients treated with TEVAR following BTAI with no history of HT at the time of trauma were enrolled. They were matched with 37 healthy volunteers based on age, sex, and body surface area and underwent a comprehensive follow-up study, including cardiovascular magnetic resonance, 24-hour ambulatory blood pressure monitoring, and assessment of carotid-femoral pulse wave velocity (cfPWV, a measure of aortic stiffness) and flow-mediated vasodilation.

RESULTS

The mean patient age was 43.5 ± 12.9 years, and the majority were male (23 of 26; 88.5%). At a mean of 120.2 ± 69.7 months after intervention, 17 patients (65%) presented with HT, 14 (54%) had abnormal nighttime blood pressure dipping, and 6 (23%) high cfPWV. New-onset HT was related to a more proximal TEVAR landing zone and greater distal oversizing. Abnormal nighttime blood pressure was related to high cfPWV, which in turn was associated with TEVAR length and premature arterial aging.

CONCLUSIONS

HT frequently occurs otherwise healthy subjects undergoing TEVAR implantation after BTAI. TEVAR stiffness and length, the proximal landing zone, and distal oversizing are potentially modifiable surgical characteristics related to abnormal blood pressure.

Reduced and Delayed Cerebrovascular Reactivity in Patients with Parkinson's Disease

BACKGROUND

Cerebrovascular dysfunction in Parkinson's disease (PD) is heterogeneous and may contribute to disease pathophysiology or progression. There is a need to understand the mechanisms by which cerebrovascular dysfunction is altered in participants with PD.

OBJECTIVES

The objective of this study is to test the hypothesis that participants with PD exhibit a significant reduction in the ability of the cerebral vessels to dilate in response to vasoactive challenges relative to healthy controls (HC).

METHODS

The current study uses a vasodilatory challenge while participants undergo functional magnetic resonance imaging to quantify the amplitude and delay of cerebrovascular reactivity in participants with PD relative to age and sex-matched HC. An analysis of covariance was used to evaluate differences in cerebrovascular reactivity amplitude and latency between PD participants and HC.

RESULTS

A significant main effect of group was observed for whole-brain cerebrovascular reactivity amplitude (F(1, 28)  = 4.38, p = 0.046, Hedge's g = 0.73) and latency (F(1, 28)  = 16.35, p < 0.001, Hedge's g = 1.42). Participants with PD exhibited reduced whole-brain amplitude and increased latencies in cerebrovascular reactivity relative to HC. The evaluation of regional effects indicates that the largest effects were observed in the cuneus, precuneus, and parietal regions.

CONCLUSIONS

PD participants exhibited reduced and delayed cerebrovascular reactivity. This dysfunction may play an important role in chronic hypoxia, neuroinflammation, and protein aggregation, mechanisms that could lead to disease progression. Cerebrovascular reactivity may serve as an important biomarker and target for future interventions. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Association between High-Sensitivity C-Reactive Protein and Blood Pressure Variability in Subacute Stage of Ischemic Stroke

The determinants of blood pressure variability (BPV) are complex. We aimed to evaluate whether circulating high-sensitivity C-reactive protein (hsCRP) is associated with short-term BPV during the subacute stage of ischemic stroke. In this observational study, a consecutive series of acute ischemic stroke patients who underwent 24 h ambulator blood pressure monitoring (ABPM) during day 4 to 10 after onset were enrolled. Multivariable linear regression models were constructed to assess relationships between hsCRP and BPV. Among a total of 325 patients analyzed, the mean age was 60 years old and 72% were male. The SD, CV, ARV of 24 h SBP and DBP were more likely to be higher in patients with hsCRP ≥ 2 mg/L, and these predispositions remained unchanged in linear regression analyses after adjusting for possible confounding factors, with a dose-response relationship when patients were additionally categorized into quartiles according to hsCRP levels using the lowest quartile as a reference category. In contrast, similar results were observed for the mean of SBP but not the mean of DBP. These results indicate that hsCRP is dose-dependently associated with short-term BPV during the subacute stage of ischemic stroke. These findings suggested that patients with a higher level of hsCRP tended to have larger blood pressure fluctuations.

Arterial Baroreflex Dysfunction Promotes Neuroinflammation by Activating the Platelet CD40L/Nuclear Factor Kappa B Signaling Pathway in Microglia and Astrocytes

Arterial baroreflex (ABR) dysfunction has previously been associated with neuroinflammation, the most common pathological feature of neurological disorders. However, the mechanisms mediating ABR dysfunction-induced neuroinflammation are not fully understood. In the present study, we investigated the role of platelet CD40 ligand (CD40L) in neuroinflammation in an in vivo model of ABR dysfunction, and microglia and astrocyte activation in vitro. ABR dysfunction was induced in Sprague‒Dawley rats by sinoaortic denervation (SAD). We used ELSA and immunofluorescence to assess the effect of platelet CD40L on glial cell polarization and the secretion of inflammatory factors. By flow cytometry, we found that rats subjected to SAD showed a high level of platelet microaggregation and upregulation of CD40L on the platelet surface. The promotion of platelet invasion and accumulation was also observed in the brain tissues of rats subjected to SAD. In the animal model and cultured N9 microglia/C6 astrocytoma cells, platelet CD40L overexpression promoted neuroinflammation and activated M1 microglia, A1 astrocytes, and the nuclear factor kappa B (NFκB) signaling pathway. These effects were partially blocked by inhibiting platelet activity with clopidogrel or inhibiting CD40L-mediated signaling. Our results suggest that during ABR dysfunction, CD40L signaling in platelets converts microglia to the M1 phenotype and astrocytes to the A1 phenotype, activating NFκB and resulting in neuroinflammation. Thus, our study provides a novel understanding of the pathogenesis of ABR dysfunction-induced neuroinflammation and indicates that targeting platelet CD40L is beneficial for treating central nervous system (CNS) disorders associated with ABR dysfunction.

Familial dysautonomia

Familial dysautonomia (FD) is an autosomal recessive hereditary sensory and autonomic neuropathy (HSAN, type 3) expressed at birth with profound sensory loss and early death. The FD founder mutation in the ELP1 gene arose within the Ashkenazi Jews in the sixteenth century and is present in 1:30 Jews of European ancestry. The mutation yield a tissue-specific skipping of exon 20 and a loss of function of the elongator-1 protein (ELP1), which is essential for the development and survival of neurons. Patients with FD produce variable amounts of ELP1 in different tissues, with the brain producing mostly mutant transcripts. Patients have excessive blood pressure variability due to the failure of the IXth and Xth cranial nerves to carry baroreceptor signals. Neurogenic dysphagia causes frequent aspiration leading to chronic pulmonary disease. Characteristic hyperadrenergic "autonomic crises" consisting of brisk episodes of severe hypertension, tachycardia, skin blotching, retching, and vomiting occur in all patients. Progressive features of the disease include retinal nerve fiber loss and blindness, and proprioceptive ataxia with severe gait impairment. Chemoreflex failure may explain the high frequency of sudden death in sleep. Although 99.5% of patients are homozygous for the founder mutation, phenotypic severity varies, suggesting that modifier genes impact expression. Medical management is currently symptomatic and preventive. Disease-modifying therapies are close to clinical testing. Endpoints to measure efficacy have been developed, and the ELP1 levels are a good surrogate endpoint for target engagement. Early intervention may be critical for treatment to be successful.

Novel Therapeutic Approaches in Inherited Neuropathies: A Systematic Review

The management of inherited neuropathies relies mostly on the treatment of symptoms. In recent years, a better understanding of the pathogenic mechanisms that underlie neuropathies has allowed for the development of disease-modifying therapies. Here, we systematically review the therapies that have emerged in this field over the last five years. An updated list of diseases with peripheral neuropathy as a clinical feature was created based on panels of genes used clinically to diagnose inherited neuropathy. This list was extended by an analysis of published data by the authors and verified by two experts. A comprehensive search for studies of human patients suffering from one of the diseases in our list yielded 28 studies that assessed neuropathy as a primary or secondary outcome. Although the use of various scales and scoring systems made comparisons difficult, this analysis identified diseases associated with neuropathy for which approved therapies exist. An important finding is that the symptoms and/or biomarkers of neuropathies were assessed only in a minority of cases. Therefore, further investigation of treatment efficacy on neuropathies in future trials must employ objective, consistent methods such as wearable technologies, motor unit indexes, MRI or sonography imaging, or the use of blood biomarkers associated with consistent nerve conduction studies.

Ampreloxetine Versus Droxidopa in Neurogenic Orthostatic Hypotension: A Comparative Review

Neurogenic orthostatic hypotension (nOH) is a disabling problem of autonomic dysfunction in patients with Parkinson's disease, which is associated with poor quality of life and higher mortality rates. The purpose of this literature review was to explore and compare the efficacy and safety of droxidopa (an existing treatment) and ampreloxetine (a newer medication) in the treatment of nOH. We used a mixed-method literature review that addresses the epidemiology, pathophysiology, and pharmacological and non-pharmacological management of nOH in Parkinson's disease in a general way, with a more exploratory approach to droxidopa- and ampreloxetine-controlled trial studies. We included a total of 10 studies of randomized controlled trials with eight studies focused on droxidopa and two studies focused on ampreloxetine. These two drugs were analyzed and compared based on the collected individual study results. Treatment of nOH in Parkinson's disease patients with droxidopa or ampreloxetine showed clinically meaningful and statistically significant improvements relative to placebo on the components of the OHSA (Orthostatic Hypotension Symptom Assessment) composite score and OHDAS (Orthostatic Hypotension Daily Activity Scale composite scores) composite score. Droxidopa had an improved effect on daily activities, with an associated increase in standing systolic blood pressure (BP), but the long-term efficacy of droxidopa has not been documented. Standing systolic BP was maintained by ampreloxetine and worsened after the withdrawal phase. This highlights the importance of conducting further research which will help us to improve the therapeutic approach for patients with nOH and Parkinson's disease.