Psychopathological Symptom Load and Distinguishable Cerebral Blood Flow Velocity Patterns in Patients With Schizophrenia and Healthy Controls: A Functional Transcranial Doppler Study

[Functional transcranial dopplerography is a diagnostic tool for cognitive impairment syndrome]

Functional transcranial dopplerography (FTCD) is a non-invasive ultrasound examination that allows recording the dynamics of cerebral blood flow parameters under conditions of factors stimulated the activity of the structures of the central nervous system. Judgments about the sensitivity and specificity of FTCD are based on the close connection between changes in the activity of the nervous (somatic) system and the response of regional cerebral blood flow (CBF). The technique is a portable and accessible diagnostic method used in assessing the possibility of expanding functional activity during the recovery period after a stroke. An increase in mental activity in response to the presentation of a cognitive task, accompanied by an increase in glucose and oxygen consumption and naturally requiring an increase in cerebral perfusion parameters, can also be assessed by changes in regional blood flow parameters while maintaining the reactive mechanisms of autoregulation. A search of literature sources was carried out in the electronic databases PubMed and Scopus. For the subject search, Medical Subject Headings were used. A total of 36 sources that mentioned the terms «cognitive function» and «functional transcranial Doppler» were selected for preliminary analysis. At the present stage, methodological problems are obvious, requiring the development and implementation of a standard package of targeted functional tests to assess cognitive status. Available equipment and software require technological solutions to ensure objective recording of changes in cerebral blood flow during testing and training.

[Cerebral hemodynamic disorders in patients with schizophrenia with concomitant metabolic syndrome]

OBJECTIVE

To identify the differences or comparability of parameters of cerebral hemodynamics between patients with schizophrenia with or without concomitant metabolic syndrome (MS).

MATERIAL AND METHODS

The study included 94 patients with schizophrenia (48 men and 46 women). A control group consisted of 40 mentally and somatically healthy individuals (17 men and 23 women) comparable in sex and age to the main group of patients. The diagnosis of metabolic syndrome was carried out according to the criteria of the International Diabetes Federation (IDF). Assessment of cerebral hemodynamics was carried out by 4 - channel rheoencephalography (REG) at rest with closed eyes. Data analysis was carried out using the Kraskel-Wallis ANOVA criterion with the procedure of automatic a posteriori pairwise comparison, the χ2 criterion and Spearman correlation analysis.

RESULTS

According to the IDF criteria, 37 (39.4%) patients were diagnosed with MS. REG results revealed significantly (p<0.05) lower indicators of blood filling in the carotid basin, elasticity of the wall of the main arteries, the tone of small-caliber arteries and arterioles, as well as higher values of the tone of medium-caliber arteries in the carotid and vertebrobasilar basins, in both groups of patients with schizophrenia compared with the control group. In patients with schizophrenia with MS, compared with patients without MS, there were lower indicators of blood filling (p=0.044 and p=0.016) and elasticity of the wall of the main arteries (p=0.044 and p=0.028) in the carotid basin on the left and right sides.

CONCLUSION

The presence of MS in patients with schizophrenia was accompanied by more pronounced disorders of cerebral blood flow in the form of a decrease in blood filling and elasticity of the wall of the main arteries in the carotid basin. The results indicate that patients with schizophrenia with MS should be considered as a group at increased risk of cerebrovascular diseases.

Vascular-related biomarkers in psychosis: a systematic review and meta-analysis

Background

While the molecular underpinnings of vascular dysfunction in psychosis are under active investigation, their implications remain unclear due to inconsistent and sometimes sparse observations. We conducted a comprehensive meta-analysis to critically assess the alterations of vascular-related molecules in the cerebrospinal fluid (CSF) and blood of patients with psychotic disorders compared with healthy individuals.

Methods

Databases were searched from inception to February 23, 2023. Meta-analyses were performed using a random-effects model. Meta-regression and subgroup analyses were conducted to assess the effects of clinical correlates.

Results

We identified 93 eligible studies with 30 biomarkers investigated in the CSF and/or blood. Among the biomarkers examined, psychotic disorders were associated with elevated CSF-to-serum albumin ratio (standardized mean difference [SMD], 0.69; 95% confidence interval [CI], 0.35-1.02); blood S100B (SMD, 0.88; 95% CI, 0.59-1.17), matrix metalloproteinase-9 (MMP-9; SMD, 0.66; 95% CI, 0.46-0.86), and zonulin (SMD, 1.17; 95% CI, 0.04-2.30). The blood levels of S100B, MMP-9, nerve growth factor (NGF), vascular endothelial growth factor (VEGF), intercellular adhesion molecule 1 (ICAM-1), and vascular adhesion molecule 1 (VCAM-1) were altered in patient subgroups differing in demographic and clinical characteristics. Blood S100B level was positively correlated with age and duration of illness. Substantial between-study heterogeneity was observed in most molecules.

Conclusion

The alterations in certain vascular-related fluid markers in psychotic disorders suggest disturbances in normal vascular structures and functions. However, not all molecules examined displayed clear evidence of changes. While potential impacts of clinical factors, including the administered treatment, were identified, the exploration remained limited. Further studies are needed to investigate the diverse patterns of expression, and understand how these abnormalities reflect the pathophysiology of psychosis and the impact of clinical factors.

The impact of hazes on schizophrenia admissions and the synergistic effect with the combined atmospheric oxidation capacity in Hefei, China

OBJECTIVES

Currently, most epidemiological studies on haze focus on respiratory diseases, cardiovascular diseases, etc. However, the relationship between haze and mental health has not been adequately explored. The purpose of this study was to investigate the influence of hazes on schizophrenia admissions and to further explore the potential interaction effect with the combined atmospheric oxidative indices (O_x and O_x^wt).

METHODS

We collected 5328 cases during the cold season from 2013 to 2015 in Hefei, China. By integrating the Poisson Generalized Linear Models with the Distributed Lag Non-linear Models, the association between haze and schizophrenia admissions was evaluated. The interaction between hazes and two combined oxidation indexes was tested by stratifying hazes and O_x, and O_x^wt.

RESULTS

Haze was found to be significantly linked to an increased risk of hospitalization for schizophrenia, and a 9-day lag effect on schizophrenia (lag 3-lag 11), with the largest effect on lag 6 (RR = 1.080, 95% confidence interval (CI): 1.046-1.116). Males, females, and <40 y (people under 40 years old) were sensitive to hazes. Furthermore, in the stratified analysis, we found synergies between two combined oxidation indexes and hazes. The interaction relative risk (IRR) and relative excess risk due to interaction (RERI) between O_x and hazes were 1.170 (95% CI: 1.071-1.277) and 0.149 (95% CI: 0.045-0.253), respectively. For O_x^wt, the IRR and RERI were 1.179 (95% CI: 1.087-1.281) and 0.159 (95% CI: 0.056-0.263), respectively. It is noteworthy that this synergistic effect was significant in males and <40 y when examining the various subgroups in the interaction analysis.

CONCLUSIONS

Our findings suggest that exposure to haze significantly increases the risk of hospitalization for schizophrenia. More significant public health benefits can be obtained by prioritizing haze periods with high combined atmospheric oxidation capacity.

Brain vasculature disturbance in schizophrenia

PURPOSE OF REVIEW

The vascular hypothesis of schizophrenia (SZ) postulates that brain endothelial dysfunction contributes to brain pathophysiology. This review discusses recent evidence for and against this hypothesis, including data related to blood-brain barrier (BBB), brain endothelium, and brain blood supply, to provide a critical weighed update.

RECENT FINDINGS

Different studies report a consistent proportion of SZ patients showing increased BBB permeability, reflected by higher levels of albumin in the cerebral spinal fluid. Of note, this was not a result of antipsychotic medication. The high inflammatory profile observed in some SZ patients is strongly associated with increased BBB permeability to circulating immune cells, and with more severe cognitive deficiencies. Also, sex was found to interact with BBB integrity and permeability in SZ. The strongest independent genetic association with SZ has been identified in FZD1, a hypoxia-response gene that is 600-fold higher expressed in early development endothelium as compared to adult brain endothelium. Regarding brain blood supply, there is evidence to suggest alterations in proper brain perfusion in SZ. Nonetheless, ex-vivo experiments suggested that widely used antipsychotics favor vasoconstriction; thus, alterations in cerebral perfusion might be related to the patients' medication.

SUMMARY

In some patients with SZ, a vulnerable brain endothelium may be interacting with environmental stressors, such as inflammation or hypoxia, converging into a more severe SZ symptomatology. Gene expression and performance of human brain endothelium could vary along with development and the establishment of the BBB; therefore, we encourage to investigate its possible contribution to SZ considering this dynamic context.

Functional transcranial Doppler: Selection of methods for statistical analysis and representation of changes in flow velocity

INTRODUCTION

Transcranial Doppler (TCD) is a method used to study cerebral hemodynamics. In the majority of TCD studies, regression analysis and analysis of variance are the most frequently applied statistical methods. However, due to the dynamic and interdependent nature of flow velocity, nonparametric tests may allow for better statistical analysis and representation of results.

METHOD

The sample comprised 30 healthy participants, aged 33.87 ± 7.48 years; with 33% (n = 10) females. During a visuo-motor task, the mean flow velocity (MFV) in the middle cerebral artery (MCA) was measured using TCD. The MFV was converted to values relative to the resting state. The results obtained were analyzed using the general linear model (GLM) and the general additional model (GAM). The fit indices of both analysis methods were compared with each other.

RESULTS

Both MCAs showed a steady increase in MFV during the visuo-motor task, smoothly returning to resting state values. During the first 20 seconds of the visuo-motor task, the MFV increased by a factor of 1.06 ± 0.07 in the right-MCA and by a factor of 1.08 ± 0.07 in the left-MCA. GLM and GAM showed a statistically significant change in MFV (GLM:F(2, 3598) = 16.76, P < .001; GAM:F(2, 3598) = 21.63, P < .001); together with effects of hemispheric side and gender (GLM:F(4, 3596) = 7.83, P < .005; GAM:F(4, 3596) = 2.13, P = .001). Comparing the models using the χ2 test for goodness of fit yields a significant difference χ2 (9.9556) = 0.6836, P < .001.

CONCLUSIONS

Both the GLM and GAM yielded valid statistical models of MFV in the MCA in healthy subjects. However, the model using the GAM resulted in improved fit indices. The GAM's advantage becomes even clearer when the MFV curves are visualized; yielding a more realistic approach to brain hemodynamics, thus allowing for an improvement in the interpretation of the mathematical and statistical results. Our results demonstrate the utility of the GAM for the analysis and representation of hemodynamic parameters.