Genetic variants of increased waist circumference in psychosis

Prevalence of metabolic syndrome and related factors in a large sample of antipsychotic naïve patients with first-episode psychosis: Baseline results from the PAFIP cohort

BACKGROUND

Few investigations have been carried out on metabolic syndrome in antipsychotic- naïve patients with schizophrenia.

METHODS

Our primary objective was to compare the prevalence of Metabolic Syndrome (MetS), as defined by the National Cholesterol Education Program, Adult Treatment Panel III in 2001 (NCEP-ATP III), between a Spanish cohort of 303 drug-naïve patients with a first episode of psychosis (FEP) without any previous cardiovascular condition, and 153 healthy individuals.

RESULTS

Participants included 303 patients with FEP (M:F 53:46) and 153 control subjects (M:F 56:43). The mean and standard deviation ages were 31(9.38) and 29 (7.57) years in the study and control groups respectively (F = 4.09; p = 0.93). We found that the prevalence of MetS in drug-naïve patients with FEP (5.6 %) was similar to the prevalence of MetS in age-sex matched controls (5.12 %). However, 60.7 % of patients with FEP met at least one of the five MetS components, while among the control subjects only 36.5 % met at least one component. Additionally, we found that other factors not included among the operational definition of MetS, but still important in cardiovascular risk, were also altered.

CONCLUSION

FEP patients have a greater risk of presenting at least one altered MetS component than healthy controls which could indicate the need of development of screening methods detecting cardiovascular risk. Likewise, gender differences in metabolic components such as waist circumference, which is a predictor of cardiovascular events have been found. Similarly, research should focus on metabolic risk predictors that include not only MetS, but also specific parameters for the early psychosis population.

SMAD4 protein is decreased in the dorsolateral prefrontal and anterior cingulate cortices in schizophrenia

OBJECTIVES

Signal transduction through the mothers against decapentaplegic (SMAD) is a family of signal transduction factors that mediate signalling of the transforming growth factor B (TGFB)-superfamily of cell regulatory proteins. A recent transcriptomic analysis of post-mortem, cortical tissue from subjects with schizophrenia found decreased mRNA expression of SMAD2 and SMAD4 in the dorsolateral prefrontal cortex (DLPFC) associated with the disorder. To expand this initial finding, we sought to determine whether SMAD2 and SMAD4 protein were also altered in the cortex from subjects with schizophrenia.

METHODS

Western blotting was used to measure SMAD2 and SMAD4 protein levels in DLPFC and anterior cingulate cortex (ACC) taken post-mortem from subjects with schizophrenia (n = 20) and matched control (n = 20) subjects.

RESULTS

Compared to controls, levels of SMAD4 were 25% lower in the DLPFC and 38% lower in the ACC from subjects with schizophrenia. By contrast, SMAD2 levels were not altered in either DLPFC or ACC.

CONCLUSIONS

Our finding of lower SMAD4 protein in the cortex suggests there are likely to be abnormalities in cortical TGFB-superfamily signalling in schizophrenia.

PPARD May Play a Protective Role against the Development of Schizophrenia

PPARD has been suggested to contribute to the etiology of schizophrenia (SCZ) with the underlying mechanisms largely unknown. Here, we first collected and analyzed the PPARD expression profile from three groups: (1) 18 healthy control (HC) subjects, (2) 14 clinical high-risk (CHR) patients, and (3) 19 early onset of SCZ (EOS) patients. After that, we conducted a systematical pathway analysis to explore the potential mechanisms involved in PPARD exerting influence on the pathological development of SCZ. Compared to the HC group, the expression of PPARD was slightly decreased in the EOS group (LFC = −0.34; p = 0.23) and increased in the CHR group (LFC = 0.65; p = 0.20). However, there was a significant difference between the EOS group and the CHR group (LFC = −0.99; p = 0.015), reflecting the amount of variation in PPARD expression before and after the onset of SCZ. Pathway analysis suggested that overexpression of PPARD may regulate ten proteins or molecules to inhibit the pathological development of SCZ, including the deactivation of eight SCZ promoters and stimulation of two SCZ inhibitors. Our results support the association between PPARD and SCZ. The pathways identified may help in the understanding of the potential mechanisms by which PPARD contributes to the etiology of SCZ.

Mitochondrial DNA copy number is associated with psychosis severity and anti-psychotic treatment

Mitochondrial pathology has been implicated in the pathogenesis of psychotic disorders. A few studies have proposed reduced leukocyte mitochondrial DNA (mtDNA) copy number in schizophrenia and bipolar disorder type I, compared to healthy controls. However, it is unknown if mtDNA copy number alteration is driven by psychosis, comorbidity or treatment. Whole blood mtDNA copy number was determined in 594 psychosis patients and corrected for platelet to leukocyte count ratio (mtDNAcn_res). The dependence of mtDNAcn_res on clinical profile, metabolic comorbidity and antipsychotic drug exposure was assessed. mtDNAcn_res was reduced with age (β = −0.210, p < 0.001), use of clozapine (β = −0.110,p = 0.012) and risperidone (β = −0.109,p = 0.014), dependent on prescribed dosage (p = 0.006 and p = 0.026, respectively), and the proportion of life on treatment (p = 0.006). Clozapine (p = 0.0005) and risperidone (p = 0.0126) had a reducing effect on the mtDNA copy number also in stem cell-derived human neurons in vitro at therapeutic plasma levels. For patients not on these drugs, psychosis severity had an effect (β = −0.129, p = 0.017), similar to age (β = −0.159, p = 0.003) and LDL (β = −0.119, p = 0.029) on whole blood mtDNAcn_res. Further research is required to determine if mtDNAcn_res reflects any psychosis-intrinsic mitochondrial changes.