Apolipoprotein serum levels related to metabolic side effects in patients with schizophrenia

Abstract

In the general population, metabolic syndrome (MetS) is associated with a 4 times relative risk of developing diabetes and approximately a 2-fold risk of coronary heart disease, stroke, and premature mortality [1]. In patients with schizophrenia the overall rate of MetS is 32.5% [1]. This contributes to having an average mortality rate that is 2-3 times higher than the general population, corresponding to a 10-25 year shortened life expectancy [2]. Antipsychotics are associated with an increased risk for several physical diseases, including obesity, dyslipidemia, diabetes mellitus [2,3]. Use both of classical conventional and modern atypical neuroleptics have been associated with metabolic disturbances; so drug-induced metabolic disturbances are observed in 39.0% of patients taking haloperidol, 44.0% - clozapine, 22.0% - aripiprazole, 33.3% - amisulpride, 34.0% - olanzapine, 35.0% – risperidone [4]. Therefore, an ongoing need exists for reliable predictors of metabolic risks in individual patients indicated for antipsychotic treatment. Apolipoproteins and cholesterol play a critical role in synapse and myelin maintenance as well as integrity and may thus be both appealing candidates in the pathogenesis of schizophrenia and biomarkers of antipsychotic induce side metabolic effects [5]. The aim of this study is to investigate serum apolipoproteins concentration in schizophrenic patients with or without metabolic syndrome and healthy donors. Methods: The study was carried out in accordance with The Code of Ethics of the World Medical Association (Declaration of Helsinki) for experiments involving humans. After obtaining approval of the study protocol by the local ethical committee, suitable participants were recruited from psychiatric hospitals. We included 53 patients with diagnosis of paranoid schizophrenia verified according to the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10: F20). Patients have been divided into two groups with and without MetS according to criteria the International Diabetes Federation (2005). All patients received antipsychotic treatment. The control group included 20 mentally and physically healthy subjects. Serum apolipoproteins A1, C3, E, A2 and C2 were measured using xMAP technology (Luminex). Statistical analysis was performed by SPSS version 20.0. Results: We found a significant decrease in the concentration of apolipoprotein A1 in the serum of schizophrenic patients with a MetS (p = 0.002) and no side effects (p = 0.013) compared with the control group. The level of ApoC3 (p = 0.001) and ApoC2 (p = 0.002) were increased in patients with schizophrenia with MetS in comparison with the control group and patients without MetS. No other significant differences were established concerning the other assayed apolipoproteins. Conclusions: Literature date and our results suggest that disturbances in level of Apo A1 play role in pathogenesis of schizophrenia while level of ApoC3 and ApoC2 can reflect the metabolic disbalance and could be a novel biomarker to predict metabolic side effects associated with antipsychotic treatment. Future studies with a larger sample size, a well-defined control group, a longer study time duration could be of great clinical utility, when these can predict antipsychotic-associated metabolic problems in patients that carry a higher cardiovascular risk. Disclosure statement: This work is supported by RSF grant N 18-15-00011