Elżbieta Gałecka

Lipid peroxidation and antioxidant protection in patients during acute depressive episodes and in remission after fluoxetine treatment

Increasing numbers of studies indicate that free radicals and their derivatives play a role in some neuropsychiatric disorders, such as depression. The aim of this study was to investigate the activities of antioxidant enzymes, lipid peroxidation and total antioxidant status (TAS) in patients suffering from major depressive disorder (MDD) as compared to healthy controls. Specifically, we wanted to estimate how fluoxetine influences antioxidant defense and lipid peroxidation. Fifty MDD patients and thirty healthy controls participated in the study. Antioxidant enzyme activities and lipid peroxidation levels were measured in erythrocytes, while TAS was measured in plasma. All measurements were taken during an acute depressive episode and then again during depression remission after a three-month fluoxetine treatment. During acute depressive episodes, patients had significantly higher activity levels of antioxidant enzymes, such as copper-zinc superoxide dismutase (SOD1) and catalase (CAT), as compared to healthy controls. Concentrations of malondialdehyde (MDA) were also significantly higher during depressive episodes. Activity levels of glutathione peroxidase (GPx) did not differ significantly between depressed patients and healthy control subjects. Moreover, the plasma total antioxidant status of the depressed patients was decreased in comparison to control subjects. After three months of fluoxetine treatment, the above parameters did not change significantly. Major depressive disorder is accompanied by disturbances in the balance between pro- and anti-oxidative processes; however, these disturbances do not improve in patients in remission after three months of fluoxetine therapy.

The expression of genes encoding for COX-2, MPO, iNOS, and sPLA2-IIA in patients with recurrent depressive disorder

BACKGROUND There is evidence that inflammation, oxidative and nitrosative stress (IO&NS) play a role in the pathophysiology of depression. There are also data indicating altered inflammatory gene expression in depressive disorder and that genetic variants of IO&NS genes are associated with increased risk of the disease in question. The aim of this study was to explore mRNA expression of four IO&NS genes PTGS2, MPO, NOS2A, and PLA2G2A coding respectively: cyclooxygenase-2 (COX-2), myeloperoxidase (MPO), inducible nitric oxide synthase (iNOS) and secretory phospholipase A2 type IIA (sPLA2-IIA). METHOD Expression of the mRNA was determined using quantitative real-time PCR, in peripheral blood cells of patients with recurrent depressive disorder (rDD) and normal controls. RESULTS The mRNA expressions of the genes encoding for COX-2, MPO, iNOS and sPLA2-IIA were significantly increased in the peripheral blood cells of depressed patients versus controls. LIMITATIONS Patients were treated with antidepressants. CONCLUSION Our results indicate and may confirm the role of peripheral IO&NS pathways in the pathophysiology of depression. The results represent a promising way to investigate biological markers of depression.

Single‐nucleotide polymorphisms and mRNA expression for melatonin synthesis rate‐limiting enzyme in recurrent depressive disorder

Abstract:  Depressive disorder (DD) is characterised by disturbances in blood melatonin concentration. It is well known that melatonin is involved in the control of circadian rhythms, sleep included. The use of melatonin and its analogues has been found to be effective in depression therapy. Melatonin synthesis is a multistage process, where the last stage is catalysed by acetylserotonin methyltransferase (ASMT), the reported rate‐limiting melatonin synthesis enzyme. Taking into account the significance of genetic factors in depression development, the gene for ASMT may become an interesting focus for studies in patients with recurrent DD. The goal of the study was to evaluate two single‐nucleotide polymorphisms (SNPs) (rs4446909; rs5989681) of the ASMT gene, as well as mRNA expression for ASMT in recurrent DD‐affected patients. We genotyped two polymorphisms in a group of 181 recurrent DD patients and in 149 control subjects. The study was performed using the polymerase chain reaction/restriction fragment length polymorphism method. The distribution of genotypes in both studied SNPs in the ASMT gene differed significantly between DD and healthy subjects. The presence of AA genotype of rs4446909 polymorphism and of GG genotype of rs5989681 polymorphism was associated with lower risk for having recurrent DD. In turn, patients with depression were characterised by reduced mRNA expression for ASMT. In addition, ASMT transcript level in both recurrent DD patients and in healthy subjects depended significantly on genotype distributions in both polymorphisms. In conclusion, our results suggest the ASMT gene as a susceptibility gene for recurrent DD.

Association between inducible and neuronal nitric oxide synthase polymorphisms and recurrent depressive disorder

BACKGROUND Major depression is characterised by increased nitric oxide (NO) levels. Inhibition of the NO synthesizing enzymes, neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS), results in antidepressant-like effects, whereas the expression of iNOS and nNOS is increased in depression. Recent studies have indicated that NOS participates in the mechanisms of antidepressants. The aim of this study was to examine whether a single nucleotide polymorphism (SNP) present in the genes encoding iNOS and nNOS can contribute to the risk of developing recurrent depressive disorder (rDD). METHODS The study was carried out in a group of 181 depressive patients and 149 control subjects of Polish origin. SNPs were assessed using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analyses. RESULTS The genotype distributions of the polymorphisms in exon 22 of the NOS2A gene and in exon 29 of the nNOS gene were significantly different between rDD patients and controls. The results showed that the G/A SNP of the gene encoding iNOS was associated with an increased susceptibility to rDD, whereas A/A homozygous carriers had a decreased risk of developing rDD. There was also a significant association between the C/T SNP of the gene encoding nNOS; the presence of the CC homozygous genotype decreased the risk of rDD, whereas the T allele and T/T homozygous genotype increased the vulnerability to rDD. CONCLUSIONS Our results suggest that polymorphisms in the iNOS and nNOS genes confer an increased susceptibility or resistance to rDD. Future research should examine genetic variants and their associations to the expression of NOSs and NO level in depressive patients.

An inducible nitric oxide synthase polymorphism is associated with the risk of recurrent depressive disorder

Evidence indicates that depressive disorder is a heterogenic disease, and oxidative stress, inflammation and impairment of neurogenesis play a role in its aetiology. Moreover, there are data suggesting that genetic factors affect the development of depression. Nitric oxide (NO) is a biological molecule with both a beneficial and a detrimental role in brain. One of the three enzymes generating NO is inducible nitric oxide synthase (iNOS). Recent studies have shown that depressed patients are characterised by excessive NO production. In addition, iNOS inhibitors are effective in depression treatment. This study investigated the importance of a functional single nucleotide polymorphism (SNP), -1026C/A, located in the promoter region of the human NOS2A gene, for the risk of recurrent depressive disorder (RDD) vulnerability. The study was carried out in a group of 181 patients with RDD and 149 ethnically matched controls. Genotyping was performed by direct sequencing of the polymerase chain reaction (PCR) products. The genotype distribution of the -1026C/A polymorphism between depressed patients and healthy controls was significantly different. Individuals who were homozygous for the CC genotype exhibited an increased risk of developing RDD. In conclusion we cautiously conclude that polymorphism in the NOS2A gene promoter may play a role in the background of RDD.

Single nucleotide polymorphisms and mRNA expression for melatonin MT2 receptor in depression

Polymorphisms (rs 4753426 and rs 794837) and expression of the melatonin MT(2) receptor gene were evaluated in 181 patients with recurrent depressive disorder (rDD) and 149 healthy subjects of Polish origin. We found an increased risk for rDD in patients with the C allele and a decreased risk in patients with the T allele (rs4753426). Patients with the AT heterozygote (rs794837) had an increased mRNA level. The significance of the MT(2) receptor gene and the risk of rDD are suggested.

Vascular endothelial growth factor gene (VEGFA) polymorphisms may serve as prognostic factors for recurrent depressive disorder development.

Recurrent depressive disorder (rDD) is a multifactorial disease. Vascular endothelial growth factor (VEGF) is one of the factors that have been suggested to play a role in the etiology and/or development of this disease. Limited information related to the role of VEGFA gene polymorphism in depressive disorder is available. The aim of the study was to analyze the association between VEGFA gene polymorphisms (+405G/C; rs2010963, +936C/T; rs 3025039), VEGFA gene expression, and its serum protein levels in rDD in the Caucasian population. In the current study, 268 patients and 200 healthy controls of the Caucasian origin were involved. Genotyping and gene expression were performed using polymerase chain reaction (PCR)-based methods. Enzyme-linked immunosorbent assay (ELISA) was used for detection of circulating serum VEGF levels. The distribution of VEGFA polymorphism +405G/C differed significantly between rDD patients and healthy subjects. The results of this study indicated that the C allele and CC genotype of VEGFA are risk factors for rDD. Haplotypes CC and TG are the important factors for depression development. Further, VEGFA mRNA expression and VEGF levels were higher in rDD patients than in controls. The VEGFA gene polymorphism may serve as a prognostic factor for rDD development. Our study showed higher levels of both VEGFA mRNA in the peripheral blood cells and serum VEGF in patients diagnosed with rDD than in healthy controls. The obtained results suggest VEGF and the gene encoding the molecule play a role in the etiology of the disease and should be further investigated.

Vascular endothelial growth factor receptor 2 gene (KDR) polymorphisms and expression levels in depressive disorder.

Recent research findings suggest that vascular endothelial growth factor (VEGF) participates in the development of depressive disorder. VEGF is involved in neurogenesis and neuroprotection processes, mediated by vascular endothelial growth factor receptor 2 (VEGFR2). VEGFR2 also plays a role in angiogenesis, a process related to neurogenesis and other biological processes. We examined VEGFR2 (KDR) gene polymorphism, mRNA expression levels, as well as VEGFR2 protein levels in 268 patients diagnosed with a recurrent depressive disorder (rDD) using the ICD-10 criteria, and in 200 healthy controls. Genotyping and gene expression level analysis was performed using polymerase chain reaction (PCR)-based methods. An Enzyme-Linked Immunosorbent Assay (ELISA) was used for measurement of KDR protein levels. Our study found that distribution of KDR polymorphism +1416T/A differs significantly in patients with rDD when compared to healthy subjects, while A allele and AA genotype are risk factors for rDD. KDR mRNA and protein expression are higher in patients with rDD. We also observed a significant association between the -271A/G variant and gene and protein levels. Our study is the first to demonstrate that the KDR gene may serve as a novel genetic marker that could participate in the etiology of rDD. This new pathway may play a role in the inflammatory pathophysiology of depression.

Is there a link between TNF gene expression and cognitive deficits in depression

Neuroinflammation is a known factor in the pathogenesis of recurrent depressive disorders. Depression is accompanied by activated immune-inflammatory pathways including increased levels of TNFα, sTNFR1and sTNFR2.The purpose of this study was to analyse the TNF-α, TNFRSF1A and TNFRSF1B genes on both mRNA and protein levels in patients with rDD, and to investigate the relationship between TNF-α,TNFRSF1A and TNFRSF1B gene expression and cognitive performance. The study comprised 158 subjects: patients with recurrent depressive disorder (n=89) and healthy subjects (n=69). Cognitive function assessment was based on: Trail Making Test, The Stroop Test, Verbal Fluency Test and Auditory Verbal Learning Test. Both mRNA and protein expression levels of all genes were significantly higher in rDD subjects when compared to healthy controls. No statistically significant correlations were observed between the analysed variables in both the rDD group and the HS test group. The only exception was noticed in the HS test group, where increased expression of TNFRSF1A and TNFRSF1B gene negatively affected the performance of the AVLT test. However, statistically significant correlations between TNF, TNFRSF1A, TNFRSF1B mRNA gene expression levels and all the neuropsychological tests used in the survey for the entire group were observed. CONCLUSIONS 1.The results of our study show increased expression of the TNF, TNFRSF1A and TNFRSF1B genes on both mRNA and protein levels in depression. 2. Elevated expression of TNF-α, TNFRSF1A and TNFRSF1B negatively correlates with cognitive efficiency: working memory, executive functions, attention, auditory-verbal memory, effectiveness of learning processes and verbal fluency.

COX-2 expression in papillary thyroid carcinoma (PTC) in cytological material obtained by fine needle aspiration biopsy (FNAB).

BackgroundCOX-2 is an enzyme isoform that catalyses the formation of prostanoids from arachidonic acid. An increased COX-2 gene expression is believed to participate in carcinogenesis. Recent studies have shown that COX-2 up-regulation is associated with the development of numerous neoplasms, including skin, colorectal, breast, lung, stomach, pancreas and liver cancers. COX-2 products stimulate endothelial cell proliferation and their overexpression has been demonstrated to be involved in the mechanism of decreased resistance to apoptosis. Suppressed angiogenesis was found in experimental animal studies as a consequence of null mutation of COX-2 gene in mice. Despite the role of COX-2 expression remains a subject of numerous studies, its participation in carcinogenesis or the thyroid cancer progression remains unclear.MethodsTwenty three (23) patients with cytological diagnosis of PTC were evaluated. After FNAB examination, the needle was washed out with a lysis buffer and the obtained material was used for COX-2 expression estimation. Total RNA was isolated (RNeasy Micro Kit), and RT reactions were performed. β-actin was used as endogenous control. Relative COX-2 expression was assessed in real-time PCR reactions by an ABI PRISM 7500 Sequence Detection System, using the ΔΔCT method.ResultsCOX-2 gene expression was higher in patients with PTC, when compared to specimens from patients with non-toxic nodular goitre (NTG).ConclusionsThe preliminary results may indicate COX-2 role in thyroid cancer pathogenesis, however the observed variability in results among particular subjects requires additional clinical data and tumor progression analysis.