Search Results (9)

Hyperbaric oxygenation (HBO₂) can modify gene and protein expression, signaling pathways, and vascular function, leading to altered vasomotor responses. Adenosine receptors (ARs) may mediate these effects by modulating vasoactivity. This study investigated flow-induced dilation (FID) and hypoxia-induced dilation (HID) in the presence or absence of A1R/A2aR agonists (CCPA and CGS-21680, respectively) and antagonists (DPCPX and SCH-58261, respectively) in isolated middle cerebral arteries (MCAs) from Sprague Dawley rats of both sexes and the direct dose-dependent effects of A1R and A2aR agonists on the vascular reactivity of MCAs. Rats were exposed to either acute HBO₂ (Ac-HBO₂) or intermittent HBO₂ over four days (In-HBO₂). Ac-HBO₂ impaired vascular responses to A1R and A2aR agonists and significantly decreased FID and HID. In both Ac-HBO₂ and In-HBO₂, A1R modulation did not significantly affect FID or HID. A2aR stimulation reduced FID in the In-HBO₂ group, while A2aR antagonism had no significant effect on HID. However, the A2aR agonist’s presence enhanced HID in In-HBO₂-exposed rats. Protein expression of A1R and A2aR decreased after Ac-HBO₂, while gene expression increased following In-HBO₂. These findings suggest that ARs play a role in HBO₂-induced vasoreactivity, which possibly changes in MCA, potentially via the modulation of ARs gene and protein expression. Full article

Psoriasis induces systemic atherosclerosis, but its impact on cerebrovascular function remains unclear. However, stroke prevention must be considered in psoriasis, as it is commonly comorbid with classic cardiovascular risk factors. Thus, the aim of the study is to assess cerebral microvasculature function and its confounders in patients with psoriasis. The study protocol included cerebral autoregulation assessment with measurements of vasomotor reactivity reserve (VMRr) on the middle cerebral arteries with the use of a Transcranial Doppler (TCD) in 50 patients with psoriasis without cerebrovascular events (46; 21–74 years) and 26 healthy controls (41; 29–58 years). Analyses of VMRr relationships with the psoriasis course, comorbidities, inflammatory markers and intima–media thickness (IMT) were performed. The study showed that VMRr was lower (64% vs. 76%, p = 0.001), and the IMT was higher (0.65 vs. 0.52 mm, p = 0.001) in patients compared to controls. The patients were also characterized by a higher body mass index (BMI) and a higher level of Il-6 than the controls (29.14 vs. 25.76 kg/m², p = 0.004 and 585 vs. 204 pg/mL, p < 0.001, respectively), but only BMI was independently impacting VMRr reduction (p = 0.02). In conclusion, early cerebral microvasculature dysfunction may occur in patients with psoriasis, and its extent is associated with an increase in BMI. Thus, body mass reduction should be strongly recommended for stroke prophylaxis in patients with psoriasis. Full article

The function of cerebral small vessels can be assessed using cerebral vasomotor reactivity (VMR). Our aim in this retrospective cross-sectional study was to investigate a correlation between carotid artery stenosis measured through ultrasonographic morphological and hemodynamic parameters and cerebral VMR. A total of 285 patients (125 males; mean age 54) were included. The breath-holding index (BHI) was used to evaluate cerebral VMR. Ultrasonographic carotid artery parameters were collected: the presence and characteristics of carotid plaques, the degree of carotid diameter stenosis, intima–media thickness (IMT), peak systolic velocity (PSV), and end diastolic velocity (EDV). Additionally, hemodynamic parameters of the middle cerebral artery (MCA) were evaluated, including the mean flow velocity (MFV) and pulsatility index (PI). The following was collected from patients’ medical histories: age, gender, and vascular risk factors. A negative correlation between the BHI and age (r = −0.242, p < 0.01), BHI and the presence of carotid plaques, BHI and IMT (r = −0.203, p < 0.01), and BHI and the PI of MCA on both sides (r = −0.268, p < 0.01) was found. We found a positive correlation between the BHI in the left MCA and EDV in the left internal carotid artery (r = 0.121, p < 0.05). This study shows the correlation between cerebral VMR and carotid stenosis but indicates a higher influence of morphological parameters on VMR values. Full article

Background: Acetazolamide is a non-competitive inhibitor of carbonic anhydrase, an enzyme expressed in different cells of the central nervous system (CNS) and involved in the regulation of cerebral blood flow (CBF). The aim of this review was to understand the effects of acetazolamide on CBF, intracranial pressure (ICP) and brain tissue oxygenation (PbtO₂) after an acute brain injury (ABI). Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA), we performed a comprehensive, computer-based, literature research on the PubMed platform to identify studies that have reported the effects on CBF, ICP, or PbtO₂ of acetazolamide administered either for therapeutic or diagnostic purposes in patients with subarachnoid hemorrhage, intracerebral hemorrhage, traumatic brain injury, and hypoxic-ischemic encephalopathy. Results: From the initial search, 3430 records were identified and, through data selection, 11 of them were included for the qualitative analysis. No data on the effect of acetazolamide on ICP or PbtO₂ were found. Cerebral vasomotor reactivity (VMR—i.e., the changing in vascular tone due to a vasoactive substance) to acetazolamide tends to change during the evolution of ABI, with the nadir occurring during the subacute stage. Moreover, VMR reduction was correlated with clinical outcome. Conclusions: This systematic review showed that the available studies on the effects of acetazolamide on brain hemodynamics in patients with ABI are scarce. Further research is required to better understand the potential role of this drug in ABI patients. Full article

Stroke during pregnancy and preeclampsia are two distinct but interrelated medical conditions, sharing a common denominator—blood control failure. Along with cardiovascular diseases, diabetes, dyslipidemia, and hypercoagulability, hypertension is undoubtedly a major risk factor associated with stroke. Even though men have higher age-specific stroke rates, women are facing higher life-long stroke risk, primarily due to longer life expectancy. Sex hormones, especially estrogen and testosterone, seem to play a key link in the chain of blood pressure control differences between the genders. Women affected with stroke are more susceptible to experience some atypical stroke manifestations, which might eventually lead to delayed diagnosis establishment, and result in higher morbidity and mortality rates in the population of women. Preeclampsia is a part of hypertensive disorder of pregnancy spectrum, and it is common knowledge that women with a positive history of preeclampsia are at increased stroke risk during their lifetime. Preeclampsia and stroke display similar pathophysiological patterns, including hypertension, endothelial dysfunction, dyslipidemia, hypercoagulability, and cerebral vasomotor reactivity abnormalities. High-risk pregnancies carrying the burden of hypertensive disorder of pregnancy have up to a six-fold higher chance of suffering from stroke. Resemblance shared between placental and cerebral vascular changes, adaptations, and sophisticated auto-regulatory mechanisms are not merely coincidental, but they reflect distinctive and complex cardiovascular performances occurring in the maternal circulatory system during pregnancy. Placental and cerebral malperfusion appears to be in the midline of both of these conditions; placental malperfusion eventually leads to preeclampsia, and cerebral to stoke. Suboptimal performances of the cardiovascular system are proposed as a primary cause of uteroplacental malperfusion. Placental dysfunction is therefore designated as a secondary condition, initiated by the primary disturbances of the cardiovascular system, rather than an immunological disorder associated with abnormal trophoblast invasion. In most cases, with properly and timely applied measures of prevention, stroke is predictable, and preeclampsia is a controllable condition. Understanding the differences between preeclampsia and stroke in pregnancy is vital for healthcare providers to enhance their clinical decision-making strategies, improve patient care, and promote positive maternal and pregnancy outcomes. Management approaches for preeclampsia and stroke require a multidisciplinary approach involving obstetricians, neurologists, and other healthcare professionals. Full article

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) primarily affects the respiratory system but can also lead to neurological complications. Among COVID-19 patients, the endothelium is considered the Achilles heel. A variety of endothelial dysfunctions may result from SARS-CoV-2 infection and subsequent endotheliitis, such as altered vascular tone, oxidative stress, and cytokine storms. The cerebral hemodynamic impairment that is caused is associated with a higher probability of severe disease and poor outcomes in patients with COVID-19. This review summarizes the most relevant literature on the role of vasomotor reactivity (VMR) in COVID-19 patients. An overview of the research articles is presented. Most of the studies have supported the hypothesis that endothelial dysfunction and cerebral VMR impairment occur in COVID-19 patients. Researchers believe these alterations may be due to direct viral invasion of the brain or indirect effects, such as inflammation and cytokines. Recently, researchers have concluded that viruses such as the Human Herpes Virus 8 and the Hantavirus predominantly affect endothelial cells and, therefore, affect cerebral hemodynamics. Especially in COVID-19 patients, impaired VMR is associated with a higher risk of severe disease and poor outcomes. Using VMR, one can gain valuable insight into a patient’s disease progression and make more informed decisions regarding appropriate treatment options. A new pandemic may develop with the COVID-19 virus or other viruses, making it essential that healthcare providers and researchers remain focused on developing new strategies for improving survival in such patients, particularly those with cerebrovascular risk factors. Full article

Early and precise neurological prognostication without self-fulfilling prophecy is challenging in post-cardiac arrest syndrome (PCAS), particularly during the targeted temperature management (TTM) period. This study aimed to investigate the feasibility of vasomotor reactivity (VMR) using transcranial Doppler (TCD) to determine whether final outcomes of patients with comatose PCAS are predicted. This study included patients who had out-of-hospital cardiac arrest in a tertiary referral hospital over 4 years. The eligible criteria included age ≥18 years, successful return of spontaneous circulation, TTM application, and bedside TCD examination within 72 h. Baseline demographics and multimodal prognostic parameters, including imaging findings, electrophysiological studies, and TCD-VMR parameters, were assessed. The final outcome parameter was cerebral performance category scale (CPC) at 1 month. Potential determinants were compared between good (CPC 1–2) and poor (CPC 3–5) outcome groups. The good outcome group (n = 41) (vs. poor (n = 117)) showed a higher VMR value (54.4% ± 33.0% vs. 25.1% ± 35.8%, p < 0.001). The addition of VMR to conventional prognostic parameters significantly improved the prediction power of good outcomes. This study suggests that TCD-VMR is a useful tool at the bedside to evaluate outcomes of patients with comatose PCAS during the TTM. Full article

Postural orthostatic tachycardia syndrome (POTS) typically occurs in youths, and early accurate POTS diagnosis is challenging. A recent hypothesis suggests that upright cognitive impairment in POTS occurs because reduced cerebral blood flow velocity (CBFV) and cerebrovascular response to carbon dioxide (CO₂) are nonlinear during transient changes in end-tidal CO₂ (P_ETCO2). This novel study aimed to reveal the interaction between cerebral autoregulation and ventilatory control in POTS patients by using tilt table and hyperventilation to alter the CO₂ tension between 10 and 30 mmHg. The cerebral blood flow velocity (CBFV), partial pressure of end-tidal carbon dioxide (P_ETCO2), and other cardiopulmonary signals were recorded for POTS patients and two healthy groups including those aged >45 years (Healthy-Elder) and aged <45 years (Healthy-Youth) throughout the experiment. Two nonlinear regression functions, Models I and II, were applied to evaluate their CBFV-P_ETCO2 relationship and cerebral vasomotor reactivity (CVMR). Among the estimated parameters, the curve-fitting Model I for CBFV and CVMR responses to CO₂ for POTS patients demonstrated an observable dissimilarity in CBFV_max (p = 0.011), mid-P_ETCO2 (p = 0.013), and P_ETCO2 range (p = 0.023) compared with those of Healthy-Youth and in CBFV_max (p = 0.015) and CVMR_max compared with those of Healthy-Elder. With curve-fitting Model II for POTS patients, the fit parameters of curvilinear (p = 0.036) and P_ETCO2 level (p = 0.033) displayed significant difference in comparison with Healthy-Youth parameters; range of change (p = 0.042), P_ETCO2 level, and CBFV_max also displayed a significant difference in comparison with Healthy-Elder parameters. The results of this study contribute toward developing an early accurate diagnosis of impaired CBFV responses to CO₂ for POTS patients. Full article

Background: Patients with Fabry’s disease (FD) may be asymptomatic or show a spectrum of clinical manifestations, including cerebrovascular disease, mainly affecting posterior circulation. Few and conflicting studies on cerebral blood flow (CBF) velocity by transcranial Doppler sonography (TCD) in asymptomatic FD (aFD) subjects have been published. Our study aims to assess TCD in aFD subjects to identify any preclinical CBF change. Methods: A total of 30 aFD subjects were consecutively recruited and compared to 28 healthy controls. Brain magnetic resonance imaging was normal in all participants. TCD was used to study blood flow velocity and indices of resistance of intracranial arteries from the middle cerebral artery (MCA), bilaterally, and from the basilar artery (BA). Cerebral vasomotor reactivity (CVR) was also evaluated from MCA. Results: No difference was found between groups for MCA parameters of CBF velocity and CVR. Compared to controls, a higher mean blood flow velocity and a lower resistance index from BA were observed in FD subjects. No correlation was found between any BA-derived TCD parameter and the level of lyso-globotriaosylceramide. Conclusions: aFD subjects show evidence of altered CBF velocity in posterior circulation. Preclinical detection of neurovascular involvement in FD might allow appropriate management and prevention of future cerebrovascular complications and disability. Full article