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Schizophrenia, a severe mental disorder characterized by chronic disability and poor quality of life, has been shown to be associated with alterations in redox balance. Recent research has suggested a potential link between the antioxidant bilirubin and schizophrenia, although findings have been inconsistent. To address this gap, we conducted a systematic review and meta-analysis to evaluate possible alterations in bilirubin concentrations in schizophrenia. A comprehensive search of major databases was conducted to identify articles reporting total and unconjugated bilirubin in schizophrenic patients and healthy controls in case-control studies. Our meta-analysis included 18 studies investigating 16,245 participants. The pooled results did not reveal any significant association between schizophrenia and total bilirubin concentrations. Additionally, such effect was strongly influenced by the results of a single study in sensitivity analysis. Subgroup and meta-regression analyses based on various factors such as study design, sample size, and geographical region showed no significant associations with the effect size, nor they identified sources of heterogeneity. Furthermore, publication bias assessments were conducted to ensure the robustness of the findings. Overall, our findings summarize the available evidence regarding the possible role of bilirubin as a biomarker of schizophrenia and highlight the importance of conducting further research in this area.
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Background: Neurological disorders, particularly those associated with aging, pose significant challenges in early diagnosis and treatment. The identification of specific biomarkers, such as platelets (PLTs), has emerged as a promising strategy for early detection and intervention in neurological health. This systematic review aims to explore the intricate relationship between PLT dynamics and neurological health, focusing on their potential role in cognitive functions and the pathogenesis of cognitive disorders. Methods: Adhering to PRISMA guidelines, a comprehensive search strategy was employed in the PubMed and Scholar databases to identify studies on the role of PLTs in neurological disorders published from 2013 to 2023. The search criteria included studies focusing on PLTs as biomarkers in neurological disorders, their dynamics, and their potential in monitoring disease progression and therapy effectiveness. Results: The systematic review included 104 studies, revealing PLTs as crucial biomarkers in neurocognitive disorders, acting as inflammatory mediators. The findings suggest that PLTs share common features with altered neurons, which could be utilised for monitoring disease progression and evaluating the effectiveness of treatments. PLTs are identified as significant biomarkers for detecting neurological disorders in their early stages and understanding the pathological events leading to neuronal death. Conclusions: The systematic review underscores the critical role of PLTs in neurological disorders, highlighting their potential as biomarkers for the early detection and monitoring of disease progression. However, it also emphasises the need for further research to solidify the use of PLTs in neurological disorders, aiming to enhance early diagnosis and intervention strategies.
RESUMO
BACKGROUND: There is a growing interest in the role of immune and inflammatory responses in mental disorders (MDs). Mean platelet volume (MPV) is an extensively utilized hemogram parameter that reflects systemic inflammation and immune function. Our research sought to determine whether a connection exists between MPV and various types of MDs. METHODS: We searched PubMed, EMBASE, PsychINFO, and Web of Science for eligible studies from inception to 15 February 2023, supplemented by manual searching the references from relevant articles. We applied standardized mean difference (SMD) and its 95% confidence interval (CI) to estimate the differences in MPV values in patients with MDs compared to controls. RESULTS: We analyzed data from 24 surveys with 4843 participants (2450 patients with MDs and 2393 healthy controls). Two-step meta-analyses were conducted to estimate the SMD in MPV value between individuals with and without MDs. Higher MPV values were substantially linked to MDs (i.e., depression, anxiety, bipolar disorder, and schizophrenia). Moderator and stratified analyses revealed that the aggregate effects were more robust in specific populations, such as younger patients and those who had not taken antipsychotic medication within the previous month. CONCLUSIONS: Our findings corroborate the role of inflammatory response in the pathogenesis of MDs and the pharmacological treatment of these conditions. Regarding the considerable heterogeneity among studies, the level of evidence was very low to moderate.