Michał Wroński

BDNF rs 6265 polymorphism and COMT rs 4680 polymorphism in deficit schizophrenia in Polish sample

BACKGROUND Deficit schizophrenia (DS) is distinguished from the group of schizophrenic psychoses based on the presence of primary negative symptoms. It differs from nondeficit (NDS) forms of schizophrenia in dimensions such as risk factors, family history, course of illness and neurobiological differences. The aim of the study was assessment of a potential association of the investigated polymorphisms of the brain-derived neurotrophic factor (BDNF) and catechol-O-methyltransferase (COMT) genes with the deficit syndrome in schizophrenia. METHODS A cohort of 200 patients with schizophrenia (81 DS and 119 NDS subjects) and a group of 100 control subjects matched for ethnicity, sex and age were recruited. Somatic and psychometric assessment were conducted as well as structured interview about the influence of adverse biological, family and social factors. Genetic analysis of the BDNF (Val66Met) rs6265 and the COMT (Val158Met) rs4680 polymorphisms was performed. RESULTS We found significant differences between DS and NDS in rs4680 COMT genotype distribution: more homozygous Val/Val were found (31 vs. 17%) in the NDS compared to the DS subgroup. No associations were found between the investigated polymorphisms of the BDNF gene and the presence of schizophrenia either in DS and NDS subgroups. CONCLUSION The analysis of the COMT rs4680 polymorphism in the present DS and NDS study shows that some genetic factors may be relevant in analyzing the reasons for the differentiation of schizophrenic subtypes.

Functional polymorphism of matrix metalloproteinase-9 (MMP9) gene is not associated with schizophrenia and with its deficit subtype

BACKGROUND The deficit subtype of schizophrenia is hypothesized to constitute a pathophysiologically distinct subgroup of schizophrenia patients suffering from enduring, idiopathic negative symptoms and various neuropsychological deficits. Matrix metalloproteinases (MMPs) are extracellularly acting endopeptidases the substrates of which are matrix and adhesion molecules. Recently, MMP9 has been shown to be involved in various forms of synaptic plasticity, learning and memory consolidation. The primary aim of the present study was to evaluate associations between the functional MMP-9 -1562C/T gene polymorphism and the deficit and non-deficit subtypes of schizophrenia. METHODS The study was conducted between 2009 and 2012. Deficit schizophrenia was diagnosed using the SDS. The sample consisted of 468 patients, Caucasians, of Polish descent with ICD 10 diagnosis of schizophrenia: 189 [51% males] were included in a non-deficit subgroup, 279 patients [53% males] were included in a deficit subgroup. The control group consisted of 532 subjects, Caucasians, of Polish descent [51% males]. MMP-9 -1562C/T gene polymorphism was genotyped using the fluorescence resonance energy transfer (FRET) method and the Light Cycler System 2.0. RESULTS The frequencies of genotypes and alleles did not differ between the schizophrenia patients and control group. The deficit and non-deficit patients did not differ in terms of the genotype and allele frequencies. No differences were found in genotype and allele frequencies between the deficit patients and the controls and between the non-deficit patients and the controls. CONCLUSION We found no evidence for the association between the functional MMP-9 -1562C/T gene polymorphism and deficit/non-deficit subtypes of schizophrenia.

Decreased use of active coping styles contributes to elevated allostatic load index in first-episode psychosis

Accumulating evidence indicates that stress plays an important role in the development of psychotic disorders. Recent studies have revealed that patients with first-episode psychosis (FEP) present systemic biological dysregulations related to stress-exposure in terms of elevated allostatic load (AL) index. However, the mechanisms underlying this observation remain unknown. Therefore, in this study we aimed to investigate the AL index with respect to stress coping strategies in 36 FEP patients and 31 matched controls. We found significantly higher AL index in FEP patients compared to controls after co-varying for potential confounding factors. Patients with FEP were less likely to use active and task-focused coping. Lower odds of using these coping styles, planning as well as positive reinterpretation and growth were related to higher AL index in FEP patients, but not in controls. Depressive symptoms were associated with lower likelihood of using task-focused coping as well as positive reinterpretation and growth. Additionally, depressive symptoms were related to higher AL index. Finally, depressive symptoms mediated the effects of task-focused coping as well as positive reinterpretation and growth on the AL index. Our results confirm systemic biological dysregulation indexed as AL in FEP patients. Lower odds of using active coping styles might contribute to higher AL index via the mediating effect of depressive symptoms in patients with FEP. Longitudinal studies are required to establish causal inferences between coping styles, depressive symptoms and the AL index in early psychosis.