Background Schizophrenia is associated with a lowered life expectancy due to cardiovascular disease. This is, at least in part, related to an increased vulnerability to the development of metabolic syndrome (MetS) in patients with schizophrenia. The dysregulation of apolipoproteins (Apos) may also play a role in the pathogenesis of schizophrenia via their effect on cerebral cholesterol processing. Aim The aim of this study was to investigate serum Apos A1, C3, E, A2 and C2 concentration in schizophrenia patients with or without MetS in comparison to healthy donors. Methods After obtaining informed consent, 53 patients with a diagnosis of paranoid schizophrenia according to ICD-10 criteria (F20) were included. Patients were divided into two groups with (N = 26) and without (N = 27) MetS according to the criteria of the International Diabetes Federation. The control group included 20 mentally and physically healthy subjects. Serum Apos A1, A2, C2, C3 and E were measured using xMAP technology (Luminex). Results Serum ApoA1 was significantly decreased in patients with schizophrenia compared to healthy subjects (p = 0.002); ApoA2 was lower in patients without MetS in comparison to patients with MetS (p = 0.017) and the levels of ApoC3 and ApoC2 were increased in patients with schizophrenia with MetS in comparison with the control group and also with patients without MetS. No other significant differences were established concerning the other assayed apolipoproteins. Conclusions In line with literature data the results of our study suggest that while disturbances in ApoA1 level may play a role in the pathogenesis of schizophrenia, ApoA2, ApoC2, ApoC3 and ApoE may be primarily related to metabolic imbalance.

The adipokines leptin, adiponectin, tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) might be associated with metabolic syndrome (MetS) in patients with schizophrenia. In the present study, we attempted to confirm the results of previous reports and assessed their MetS-related correlation with body fat composition and biochemical parameters. We measured in 46 patients with schizophrenia and MetS serum levels of adiponectin insulin, leptin, TNF-α and IL-6 and compared these levels to those of patients with schizophrenia without MetS. The MetS patients had significantly increased leptin levels and leptin/adiponectin ratios, as well as decreased adiponectin levels. Leptin levels correlated with several metabolic parameters, both in patients with and without MetS, including body fat percentage, total fat fold, and body mass index (BMI). Patients without abnormal MetS components had lower levels of leptin and leptin/adiponectin ratios compared with patients who had one or two MetS components. Leptin/adiponectin ratios were higher in patients who had four rather than three MetS components. Multiple regression analysis revealed multiple associations for leptin but only one for adiponectin, TNF-α, and IL-6. Our results support an important pathophysiological role for leptin more than adiponectin in patients with schizophrenia with MetS.

The present study aims at comparing the change in cytokine levels in schizophrenia patients treated with atypical antipsychotics, with or without metabolic syndrome (MetS). The study included 101 patients with schizophrenia, 38 with and 63 without MetS, who received risperidone, quetiapine, olanzapine or aripiprazole for six weeks. We analyzed the concentration of 21 cytokines in the serum patients. The treatment with atypical antipsychotics changed some proinflammatory cytokine levels. It led to increased IFN-α2 (p = 0.010), IL-1α (p = 0.024) and IL-7 (p = 0.017) levels in patients with MetS, whereas the same treatment led to decreased levels of IFN-γ (p = 0.011), IL-1β (p = 0.035), IL-12р40 (p = 0.011), IL-17A (p = 0.031), IL-6 (p = 0.043) and TNF-α (p = 0.012) in individuals without MetS. Our results demonstrated the effects of atypical antipsychotics on the immune–inflammatory parameters, depending on the metabolic disturbances in schizophrenia patients.