Peripheral endothelial dysfunction in patients suffering from acute schizophrenia: a potential marker for cardiovascular morbidity?

Vascular Schizophrenia-like Psychosis in Older Adults

BACKGROUND

The aims of this study were to analyze prevalence and severity of vascular risk factors in older patients referred to our clinic due to onset of Very Late-Onset Schizophrenia-Like Psychosis (VLOSLP) and to create a specific phenotype based on pathophysiological insight rather than age of onset.

METHODS

In a longitudinal study, 103 (M = 39, F = 64; mean age of 80.32 ± 7.65 years) patients were evaluated with cognitive, neuropsychiatric, and functional assessment scales. Blood concentration of hemoglobin (Hb), mean corpuscular volume (MCV), platelets, total protein test (TPT), creatinine, azotemia, glycemia, total cholesterol (TC), triglycerides (TG), uric acid (UA), sodium (Na), potassium (K), chlorine (Cl), calcium (Ca), folate, vitamin B12 (Vit-B12), and homocysteine were measured. Presence/absence of tobacco use, alcohol consumption, psychoactive substance use, hypertension, hyperlipidemia, diabetes mellitus, and history of vascular disease were collected.

RESULTS

Females were more apathetic than males (NPI-Apathy: p = 0.040). Males had a significantly higher level of Hb (p = 0.019) and UA (p = 0.001), and a lower level of platelets (p = 0.004) and Ca (p = 0.003), and used more tobacco (p = 0.046) and alcohol (p = 0.024) than females. Comparing patients < 80 and ≥80 years, we found differences in frequency of vascular risk factors among men (p = 0.027). In total, 102 patients were treated for psychosis (59.16% of them were using atypical antipsychotics).

CONCLUSIONS

The results of this study could be useful for a progressive demonstration of the causal relationship between cardiac and cerebral vascular events and VLOSLP.

Choroidal structural analysis in ultra-high risk and first-episode psychosis

Both structural and functional alterations in the retina and the choroid of the eye, as parts of the central nervous system, have been shown in psychotic disorders, especially in schizophrenia. In addition, genetic and imaging studies indicate vascular and angiogenesis anomalies in the psychosis spectrum disorders. In this ocular imaging study, choroidal structure and vascularity were investigated using enhanced depth imaging (EDI) optical coherence tomography (OCT) in first-episode psychosis (FEP), ultra-high risk for psychosis (UHR-P), and age- and gender- matched healthy controls (HCs). There were no significant differences between groups in central choroidal thickness, stromal choroidal area (SCA), luminal choroidal area (LCA) and total subfoveal choroidal area. The LCA/SCA ratio (p<0.001) and the choroidal vascularity index (CVI) (p<0.001) were significantly different between FEP, UHR-P and HCs. CVI and LCA/SCA ratio were significantly higher in patients with FEP compared to help-seeking youth at UHR-P. CVI and LCA/SCA ratio were not different between UHR-P and HCs. However, CVI was higher in UHR-P compared to HCs after excluding the outliers for the sensitivity analysis (p = 0.002). Current findings suggest that choroidal thickness is normal, but there are abnormalities in choroidal microvasculature in prodromal and first-episode psychosis. Further longitudinal studies are needed to investigate oculomics, especially CVI, as a promising biomarker for the prediction of conversion to psychosis in individuals at clinical high-risk.

A role for endothelial NMDA receptors in the pathophysiology of schizophrenia

Numerous genetic and postmortem studies link N-methyl-d-aspartate receptor (NMDAR) dysfunction with schizophrenia, forming the basis of the popular glutamate hypothesis. Neuronal NMDAR abnormalities are consistently reported from both basic and clinical experiments, however, non-neuronal cells also contain NMDARs, and are rarely, if ever, considered in the discussion of glutamate action in schizophrenia. We offer an examination of recent discoveries elucidating the actions and consequences of NMDAR activation in the neuroendothelium. While there has been mixed literature regarding blood flow alterations in the schizophrenia brain, in this review, we posit that some common findings may be explained by neuroendothelial NMDAR dysfunction. In particular, we emphasize that endothelial NMDARs are key mediators of neurovascular coupling, where increased neuronal activity leads to increased blood flow. Based on the broad conclusions that hypoperfusion is a neuroanatomical finding in schizophrenia, we discuss potential mechanisms by which endothelial NMDARs contribute to this disorder. We propose that endothelial NMDAR dysfunction can be a primary cause of neurovascular abnormalities in schizophrenia. Importantly, functional MRI studies using BOLD signal as a proxy for neuron activity should be considered in a new light if neurovascular coupling is impaired in schizophrenia. This review is the first to propose that NMDARs in non-excitable cells play a role in schizophrenia.

Vasomotion analysis of speed resolved perfusion, oxygen saturation, red blood cell tissue fraction, and vessel diameter: Novel microvascular perspectives

BACKGROUND

Vasomotion is the spontaneous oscillation in vascular tone in the microcirculation and is believed to be a physiological mechanism facilitating the transport of blood gases and nutrients to and from tissues. So far, Laser Doppler flowmetry has constituted the gold standard for in vivo vasomotion analysis.

MATERIALS AND METHODS

We applied vasomotion analysis to speed-resolved perfusion, oxygen saturation, red blood cell tissue (RBC) tissue fraction, and average vessel diameter from five healthy individuals at rest measured by the newly developed Periflux 6000 EPOS system over 10 minutes. Magnitude scalogram and the time-averaged wavelet spectra were divided into frequency intervals reflecting endothelial, neurogenic, myogenic, respiratory, and cardiac function.

RESULTS

Recurrent high-intensity periods of the myogenic, neurogenic, and endothelial frequency intervals were found. The neurogenic activity was considerably more pronounced for the oxygen saturation, RBC tissue fraction, and vessel diameter signals, than for the perfusion signals. In a correlation analysis we found that changes in perfusion in the myogenic, neurogenic, and endothelial frequency intervals precede changes in the other signals. Furthermore, changes in average vessel diameter were in general negatively correlated to the other signals in the same frequency intervals, indicating the importance of capillary recruitment.

CONCLUSION

We conclude that vasomotion can be observed in signals reflecting speed resolved perfusion, oxygen saturation, RBC tissue fraction, and vessel diameter. The new parameters enable new aspects of the microcirculation to be observed.

Parasympathetic activity as a potential biomarker of negative symptoms in patients with schizophrenia

INTRODUCTION

Autonomic dysfunction in patients with schizophrenia has raised concern considering the higher cardiovascular mortality and morbidity rate. This phenomenon has been demonstrated using various measurements and is inferred to be associated with demographics, medical treatment, and psychopathology. However, few have targeted the role of negative symptoms within schizophrenia.

METHODS

Schizophrenia patients with stationary psychopathology were recruited from a chronic ward, a daycare center, and a nonintensive case management program. Demographic data, medication history, the Positive and Negative Syndrome Scale (PANSS) score, the Personal and Social Performance Scale (PSP) score, and the five-minute resting-state heart rate variability (HRV) were collected at trial initiation (Time 1) and a year later (Time 2). The relationships between variables and HRV indices were evaluated using correlation and regression analyses.

RESULTS

A total of 63 participants were recruited at Time 1, with 29 participants remaining at Time 2. Correlation analyses showed a negative correlation between the PANSS negative score (PANSS-N) and total power (TP), low-frequency power (LF), and high-frequency power (HF) at Time 1. The results were further examined with multiple linear regression analysis and remained significant between the PANSS-N score and HF (β = -0.306, P = .012). A generalized estimating equation model revealed the above negative association to be significant considering both timepoints.

DISCUSSION

The negative association between negative symptom severity and parasympathetic activity was significant, which may inspire further research into the corresponding treatment, the mechanisms, and the use of HRV as an applicable biomarker for treatment response.

The Inflamed Brain in Schizophrenia: The Convergence of Genetic and Environmental Risk Factors That Lead to Uncontrolled Neuroinflammation

Schizophrenia is a disorder with a heterogeneous etiology involving complex interplay between genetic and environmental risk factors. The immune system is now known to play vital roles in nervous system function and pathology through regulating neuronal and glial development, synaptic plasticity, and behavior. In this regard, the immune system is positioned as a common link between the seemingly diverse genetic and environmental risk factors for schizophrenia. Synthesizing information about how the immune-brain axis is affected by multiple factors and how these factors might interact in schizophrenia is necessary to better understand the pathogenesis of this disease. Such knowledge will aid in the development of more translatable animal models that may lead to effective therapeutic interventions. Here, we provide an overview of the genetic risk factors for schizophrenia that modulate immune function. We also explore environmental factors for schizophrenia including exposure to pollution, gut dysbiosis, maternal immune activation and early-life stress, and how the consequences of these risk factors are linked to microglial function and dysfunction. We also propose that morphological and signaling deficits of the blood-brain barrier, as observed in some individuals with schizophrenia, can act as a gateway between peripheral and central nervous system inflammation, thus affecting microglia in their essential functions. Finally, we describe the diverse roles that microglia play in response to neuroinflammation and their impact on brain development and homeostasis, as well as schizophrenia pathophysiology.

Symptomatic psychosis risk and physiological fluctuation in functional MRI data

BACKGROUND

Physiological brain pulsations have been shown to play a critical role in maintaining interstitial homeostasis in the glymphatic brain clearance mechanism. We investigated whether psychotic symptomatology is related to the physiological variation of the human brain using fMRI.

METHODS

The participants (N = 277) were from the Northern Finland Birth Cohort 1986. Psychotic symptoms were evaluated with the Positive Symptoms Scale of the Structured Interview for Prodromal Syndromes (SIPS). We used the coefficient of variation of BOLD signal (CV_BOLD) as a proxy for physiological brain pulsatility. The CV_BOLD-analyses were controlled for motion, age, sex, and educational level. The results were also compared with fMRI and voxel-based morphometry (VBM) meta-analyses of schizophrenia patients (data from the Brainmap database).

RESULTS

At the global level, participants with psychotic-like symptoms had higher CV_BOLD in cerebrospinal fluid (CSF) and white matter (WM), when compared to participants with no psychotic symptoms. Voxel-wise analyses revealed that CV_BOLD was increased, especially in periventricular white matter, basal ganglia, cerebellum and parts of the cortical structures. Those brain regions, which included alterations of physiological fluctuation in symptomatic psychosis risk, overlapped <6% with the regions that were found to be affected in the meta-analyses of previous fMRI and VBM studies in schizophrenia patients. Motion did not vary as a function of SIPS.

CONCLUSIONS

Psychotic-like symptoms were associated with elevated CV_BOLD in a variety of brain regions. The CV_BOLD findings may produce new information about cerebral physiological fluctuations that have been out of reach in previous fMRI and VBM studies.

Neurovascular Unit Dysfunction and Blood-Brain Barrier Hyperpermeability Contribute to Schizophrenia Neurobiology: A Theoretical Integration of Clinical and Experimental Evidence

Schizophrenia is a psychotic disorder characterized by delusions, hallucinations, negative symptoms, as well as behavioral and cognitive dysfunction. It is a pathoetiologically heterogeneous disorder involving complex interrelated mechanisms that include oxidative stress and neuroinflammation. Neurovascular endothelial dysfunction and blood-brain barrier (BBB) hyperpermeability are established mechanisms in neurological disorders with comorbid psychiatric symptoms such as epilepsy, traumatic brain injury, and Alzheimer's disease. Schizophrenia is frequently comorbid with medical conditions associated with peripheral vascular endothelial dysfunction, such as metabolic syndrome, cardiovascular disease, and diabetes mellitus. However, the existence and etiological relevance of neurovascular endothelial dysfunction and BBB hyperpermeability in schizophrenia are still not well recognized. Here, we review the growing clinical and experimental evidence, indicating that neurovascular endotheliopathy and BBB hyperpermeability occur in schizophrenia patients. We present a theoretical integration of human and animal data linking oxidative stress and neuroinflammation to neurovascular endotheliopathy and BBB breakdown in schizophrenia. These abnormalities may contribute to the cognitive and behavioral symptoms of schizophrenia via several mechanisms involving reduced cerebral perfusion and impaired homeostatic processes of cerebral microenvironment. Furthermore, BBB disruption can facilitate interactions between brain innate and peripheral adaptive immunity, thereby perpetuating harmful neuroimmune signals and toxic neuroinflammatory responses, which can also contribute to the symptoms of schizophrenia. Taken together, these findings support the "mild encephalitis" hypothesis of schizophrenia. If neurovascular abnormalities prove to be etiologically relevant to the neurobiology of schizophrenia, then targeting these abnormalities may represent a promising therapeutic strategy.

A Population-Based Cohort Study on Peripheral Arterial Disease in Patients with Schizophrenia

Purpose

Peripheral arterial disease (PAD) is considered the leading cause of atherosclerotic cardiovascular morbidity. Several risk factors of PAD have been observed in patients with schizophrenia. Therefore, we hypothesize that the incidence of PAD is higher in the schizophrenia population than in the general population.

Methods

The patients in this population-based cohort study were selected from the Taiwanese National Health Insurance Research Database on the basis of the claims data from 2000 to 2011. We compared the incidence of PAD between schizophrenia and nonschizophrenia cohorts. Cox proportional hazard regression models were employed for analyzing the risk of PAD after adjustment for sex, age, and comorbidities.

Results

The adjusted hazard ratio (HR) for PAD in the schizophrenia cohort was 1.26-fold higher than that in the nonschizophrenia cohort. Furthermore, patients with schizophrenia using atypical antipsychotics exhibited a high adjusted HR for PAD.

Conclusion

Compared with the general population, the risk of PAD is higher among patients with schizophrenia. Early diagnosis and intervention can mitigate complications resulting from cardiovascular diseases and lower mortality.

Microvascular dysfunction in schizophrenia: a case-control study

Background:

Schizophrenia is a mental illness associated with cardiovascular disease at a younger age than in the general population. Endothelial dysfunction has predictive value for future cardiovascular events; however, the impact of a diagnosis of schizophrenia on this marker is unknown.

Aims:

We tested the hypothesis that subjects with schizophrenia have impaired endothelial function.

Methods:

A total of 102 subjects (34.5±7.5 years) participated in this study. This sample consisted of 51 subjects with a diagnosis of schizophrenia and 51 healthy subjects, who were matched for age (P=0.442), sex (P>0.999), and smoking status (P=0.842). Peripheral artery microvascular and conduit vessel endothelial function was measured using hyperemic velocity time integral (VTI), pulse arterial tonometry (PAT), and flow-mediated dilation (FMD).

Results:

Significantly lower values of VTI were noted in subjects with schizophrenia (104.9±33.0 vs. 129.1±33.8 cm, P<0.001), whereas FMD (P=0.933) and PAT (P=0.862) did not differ between the two groups. A multivariable-linear-regression analysis, built on data from univariate and partial correlations, showed that only schizophrenia, sex, lipid-lowering medications, antihypertensive medications, and low-density lipoprotein (LDL)-cholesterol were predictive of attenuated VTI, whereas age, ethnicity, family history of cardiovascular disease, smoking status, systolic blood pressure, waist circumference, HDL-cholesterol, triglycerides, C-reactive protein, and homeostatic model assessment-insulin resistance (HOMA-IR), antidiabetic medications, antidepressant medications, mood stabilizers, benzodiazepines, and anticholinergic medications did not predict VTI in this model (adjusted R²=0.248).

Conclusions:

Our findings suggest that a diagnosis of schizophrenia is associated with impaired microvascular function as indicated by lower values of VTI, irrespective of many other clinical characteristics. It might be an early indicator of cardiovascular risk in schizophrenia, and might help to identify high-risk individuals.

Retinal microvessels reflect familial vulnerability to psychotic symptoms: A comparison of twins discordant for psychotic symptoms and controls

Mounting evidence suggests that individuals with schizophrenia have an underlying vulnerability to cardiovascular disease, and a recent study suggested that this vulnerability might be reflected in the retinal microvasculature. The purpose of this study was to test the hypothesis that the retinal microvessels reflect familial vulnerability to psychotic symptoms. Participants were 531 adolescent and young adult twins who took part in the Brisbane Longitudinal Twin Study and the Twins Eye Study in Tasmania. The twins had photographs taken of their retina when they were adolescents or young adults (M age=20.6 years), and retinal vessel diameter was assessed using computer software. The twins completed an assessment of psychosis symptoms approximately six years later. We compared retinal venular diameters of individuals with one or more symptoms of psychosis (n=45), their unaffected co-twins (n=24), and controls (n=462). Individuals with one or more symptoms of psychosis had wider venules (standardized mean=0.29) than controls (standardized mean=-0.04; p=.03), and unaffected co-twins had venular diameters that were intermediate (standardized mean=0.13) between the two groups, suggesting that wide venules may represent a proxy marker of familial vulnerability to psychosis symptoms. Consistent with previous work, there were no differences in arteriolar diameter between individuals with and without symptoms of psychosis. Findings suggest that wide retinal venules may serve as a proxy marker of familial liability to psychosis symptoms. The pathophysiological mechanisms linking psychosis and cardiovascular disease may be operative from early in life, possibly at the level of the microvasculature.

Detrimental effects of chemotherapeutics and other drugs on the endothelium: A call for endothelial toxicity profiling

The vascular endothelium is a real "maestro of circulation", and endothelial dysfunction leads to atherothrombosis, its cardiovascular complications, as well as to many other diseases. It is surprising that quite a large number of drugs seem to hamper the vasoprotective mechanisms of the endothelium, possibly promoting the development of cardiovascular diseases in patients initially treated for non-cardiological conditions. Toxicity profiling (including cardiac and liver toxicity assessment) is a routine procedure performed during pre-clinical drug development. Unfortunately, endothelium-dependent side effects are not taken into account in standard toxicity profiling protocols, as the "endothelial safety" of drugs is not required in order to enter the clinical phase of drug development. Presumably, this might be one of the reasons why several efficient therapeutics, including rofecoxib (COX-2 inhibitor), torcetrapib (CETP-inhibitor), and bardoxolone (Nrf2 activator), have unexpectedly displayed clinically significant cardiovascular hazard, resulting in their withdrawal from the market or alarming comments, respectively. In this review, we will briefly characterize the endothelial activity profiles of chemotherapeutics, antidepressants and antipsychotics-all drugs prescribed for severe, life-threatening and/or life-long diseases-and will show that at least some of them may display clinically relevant detrimental effects on endothelial function.

The bidirectional relation between psychiatric disorders with selected cardiovascular and endocrinal diseases: an Egyptian perspective

Cardiovascular and endocrine diseases may act as burdens for individuals suffering from one of these medical illnesses, and whether through the ensuing psychological distress, or some biological mechanisms, these medical diseases can eventually lead to the development of psychiatric morbidities. Moreover, psychiatric morbidities negatively affect the prognosis of both cardiovascular and endocrine diseases. Despite transcultural differences, Egyptian patients with ischemic heart diseases (ISHD), heart failure (HF), diabetes mellitus (DM), or thyroid diseases (TD) endure the same psychological distress as their Western counterparts. Psychiatric assessment and evaluation should be regularly repeated among patients with cardiovascular and endocrinal diseases, and patients who are at risk should be closely followed up.

Cognition and autonomic function in schizophrenia: inferior cognitive test performance in electrodermal and niacin skin flush non-responders

BACKGROUND

Patients with schizophrenia suffer from a broad range of cognitive disturbances. The impact in terms of functional outcome is significant. There are also several reports of disturbed autonomic regulation in the disease. The present study examined cognitive function as well as psychophysiological parameters in patients with schizophrenia and healthy controls.

METHODS

Twenty-five patients and 14 controls were investigated with electrodermal activity (EDA), an oral niacin skin flush test and a comprehensive neurocognitive test program including the Wechsler battery (WAIS-R), Fingertapping Test, Trail Making Test, Verbal Fluency, Benton Visual Retention Test, Wisconsin Card Sorting Test and Rey Auditory Verbal Learning Test.

RESULTS

The patients generally had inferior test results compared to controls. Further analysis revealed that the EDA non-responding patient group explained this variation with significant lower test results than controls. On executive tests, EDA non-responders also performed significantly worse than EDA responding patients. The small group of niacin non-responding patients exhibited an even lower overall test performance. Delayed niacin flush also correlated inversely with psychomotor function and IQ in the patients.

CONCLUSION

The findings support the hypothesis of a neurodevelopment disturbance affecting both autonomic function and higher cortical function in schizophrenia.

Endothelial nitric oxide synthetase genetic variants, metabolic syndrome and endothelial function in schizophrenia

OBJECTIVE

The increasing rates of metabolic syndrome and cardiovascular disease in schizophrenia led to investigation into their causes, including atypical antipsychotics and pharmacogenetic variants. This study focused on the peripheral vasculature as a cardiovascular phenotype and the influence of atypical antipsychotics, the aberrant metabolism of nitric oxide caused by endothelial nitric oxide synthetase (eNOS) genetic variants and metabolic syndrome in a cross-sectional sample of schizophrenia subjects.

METHODS

Associations between eNOS genetic variants and endothelial function was assessed in a cohort of schizophrenia patients taking antipsychotic drugs, whom were undergoing a clinical assessment for endothelial function via the method of peripheral artery tonometry (RH-PAT), as well as metabolic syndrome criteria screening. Analyses were conducted on the entire cohort, then again after stratifying by metabolic syndrome, to investigate the effect of the eNOS variants and metabolic syndrome on endothelial functionality.

RESULTS

We included 203 subjects with a mean age of 46 years. The cohort was 36% female, 36% had metabolic syndrome and 85% were currently using atypical antipsychotics. We found associations between the eNOS T⁻⁷⁸⁶C and worse endothelial functioning (lower RH-PAT values) only in schizophrenia patients without metabolic syndrome.

CONCLUSIONS

Our results suggested that when schizophrenia patients progress to meet metabolic syndrome criteria, the genetic protection of the eNOS T⁻⁷⁸⁶C variant on endothelial function is no longer seen: Other factors of this pro-inflammatory state may be overriding this effect. The results of this study need replication and the factors driving endothelial dysfunction in patients with metabolic syndrome warrant further investigation.

Assessment of arterial stiffness among schizophrenia-spectrum disorders using aortic pulse wave velocity and arterial compliance: a pilot study

Cardiovascular disease (CVD) is the leading cause of death in individuals with chronic schizophrenia. Arterial stiffness provides a non-invasive indication of cardiovascular disease risk. To date, arterial stiffness, which has been shown to have independent predictive value for CVD morbidity and mortality, has not been evaluated in this population. We aimed to examine aortic pulse wave velocity (aPWV) as well as large and small artery compliance (Comp1 and Comp2) in patients being treated for schizophrenia, compared to healthy volunteers. Ten patients and 10 age and gendermatched volunteers underwent a comprehensive evaluation of arterial stiffness including: aPWV, Comp1, Comp2, stroke volume, cardiac output, and systemic vascular resistance. Patient aPWV was significantly elevated compared to healthy volunteers (9.1 ± 4.11 vs. 5.7 ± 1.4, P=0.03). Increased age, blood pressure, heart rate, and cigarettes/day were associated with reduced arterial health in patients. This is the first time aPWV has been described in those treated for schizophrenia. Arterial stiffness is increased in this population. Measuring arterial stiffness is a non-invasive, sensitive and effective tool for evaluating CVD risk in this population.

Microvascular abnormality in schizophrenia as shown by retinal imaging

OBJECTIVE

Retinal and cerebral microvessels are structurally and functionally homologous, but unlike cerebral microvessels, retinal microvessels can be noninvasively measured in vivo by retinal imaging. The authors tested the hypothesis that individuals with schizophrenia exhibit microvascular abnormality and evaluated the utility of retinal imaging as a tool for schizophrenia research.

METHOD

Participants were members of the Dunedin Study, a population-representative cohort followed from birth with 95% retention. Study members underwent retinal imaging at age 38. The authors assessed retinal arteriolar and venular caliber for all members of the cohort, including individuals who developed schizophrenia.

RESULTS

Study members who developed schizophrenia were distinguished by wider retinal venules, suggesting microvascular abnormality reflective of insufficient brain oxygen supply. Analyses that controlled for confounding health conditions suggested that wider retinal venules are not simply an artifact of co-occurring health problems in schizophrenia patients. Wider venules were also associated with a dimensional measure of adult psychosis symptoms and with psychosis symptoms reported in childhood.

CONCLUSIONS

The findings provide initial support for the hypothesis that individuals with schizophrenia show microvascular abnormality. Moreover, the results suggest that the same vascular mechanisms underlie subthreshold symptoms and clinical disorder and that these associations may begin early in life. These findings highlight the promise of retinal imaging as a tool for understanding the pathogenesis of schizophrenia.

Endothelial dysfunction during acute alcohol withdrawal syndrome

BACKGROUND

Endothelial dysfunction (EF) is a central phenomenon in a variety of conditions associated with increased cardiovascular morbidity. Here, we investigated EF during acute alcohol withdrawal syndrome before and 24h after medication. We aimed to analyze microcirculation, applying the post-occlusive reactive hyperemia (PORH) test and spectral analysis of skin vasomotion as markers of EF. Additionally, we explored whether segmentation of spectral analysis data may disclose more detailed information on dynamic blood flow behavior.

METHODS

We investigated 30 unmedicated patients during acute alcohol withdrawal syndrome and matched controls. Patients were reinvestigated after 24h when half of them had been treated with clomethiazole. Capillary blood flow was assessed on the right forearm after compression of the brachial artery. Parameters of PORH such as time to peak (TP), slope and PORH indices were calculated. Spectral analysis was performed in order to study five different frequency bands. Withdrawal symptoms were quantified by means of the alcohol withdrawal scale (AW scale).

RESULTS

We observed a blunted hyperemic response in patients after occlusion of the brachial artery indicated by significantly increased TP and decreased PORH indices. In contrast, vasomotion as investigated by spectral analysis was not altered. Segmentation analysis revealed some alterations in the cardiac band at rest, and indicated differences between treated and untreated patients after 24h.

CONCLUSION

Our results suggest peripheral endothelial dysfunction in patients during acute alcohol withdrawal. No major influence of treatment was observed. Future studies need to address the relation of EF to cardiac morbidity during alcohol withdrawal.

Cerebral microvascular endothelium and the pathogenesis of neurodegenerative diseases

Diseases of the central nervous system (CNS) pose a significant health challenge, but despite their diversity, they share many common features and mechanisms. For example, endothelial dysfunction has been implicated as a crucial event in the development of several CNS disorders, such as Alzheimer disease, Parkinson disease, amyotrophic lateral sclerosis, multiple sclerosis, human immunodeficiency virus (HIV)-1-associated neurocognitive disorder and traumatic brain injury. Breakdown of the blood–brain barrier (BBB) as a result of disruption of tight junctions and transporters, leads to increased leukocyte transmigration and is an early event in the pathology of these disorders. The brain endothelium is highly reactive because it serves as both a source of, and a target for, inflammatory proteins and reactive oxygen species. BBB breakdown thus leads to neuroinflammation and oxidative stress, which are implicated in the pathogenesis of CNS disease. Furthermore, the physiology and pathophysiology of endothelial cells are closely linked to the functioning of their mitochondria, and mitochondrial dysfunction is another important mediator of disease pathology in the brain. The high concentration of mitochondria in cerebrovascular endothelial cells might account for the sensitivity of the BBB to oxidant stressors. Here, we discuss how greater understanding of the role of BBB function could lead to new therapeutic approaches for diseases of the CNS that target the dynamic properties of brain endothelial cells.