Oxidative stress related markers in the “VITA” and the centenarian projects

Identification of Novel Phyto-chemicals from Ocimum basilicum for the Treatment of Parkinson's Disease using In Silico Approach

BACKGROUND

Parkinson's disease is characterized by decreased level of dopaminergic neurotransmitters and this decrease is due to the degradation of dopamine by protein Monoamine Oxidase B (MAO-B). In order to treat Parkinson's disease, MAO-B should be inhibited.

OBJECTIVE

To find out the novel phytochemicals from plant Ocimum basilicum that can inhibit MAO-B by using the in silico methods.

METHODS

The data of chemical constituents from plant Ocimum basilicum was collected and inhibitory activity of these phytochemicals was then predicted by using the Structure-Based (SB) and Ligand-Based Virtual Screening (LBVS) methods. Molecular docking, one of the common Structure-Based Virtual Screening method, has been used during this search. Traditionally, molecular docking is used to predict the orientation and binding affinity of the ligand within the active site of the protein. Molegro Virtual Docker (MVD) software has been used for this purpose. On the other hand, Random Forest Model, one of the LBVS method, has also been used to predict the activity of these chemical constituents of Ocimum basilicum against the MAO-B.

RESULTS

During the docking studies, all the 108 compounds found in Ocimum basilicum were docked within the active site of MAO-B (PDB code: 4A79) out of which, 57 compounds successfully formed the hydrogen bond with tyr 435, a crucial amino acid for the biological activity of the enzyme. Rutin (-182.976 Kcal/mol), Luteolin (-163.171 Kcal/mol), Eriodictyol-7-O-glucoside (- 160.13 Kcal/mol), Rosmarinic acid (-133.484 Kcal/mol) and Isoquercitrin (-131.493 Kcal/mol) are among the top hits with the highest MolDock score along with hydrogen interaction with tyr 435. Using the RF model, ten compounds out of 108 chemical constituent of Ocimum basilicum were predicted to be active, Apigenin (1.0), Eriodictyol (1.0), Orientin (0.876), Kaempferol (0.8536), Luteolin (0.813953) and Rosmarinic-Acid (0.7738095) are predicted to be most active with the highest RF score.

CONCLUSION

The comparison of the two screening methods show that the ten compounds that were predicted to be active by the RF model, are also found in top hits of docking studies with the highest score. The top hits obtained during this study are predicted to be the inhibitor of MAO-B, thus, could be used further for the development of drugs for the treatment of Parkinson's disease (PD).

A comprehensive review of monoamine oxidase inhibitors as Anti-Alzheimer's disease agents: A review

Monoamine oxidases (MAO-A and MAO-B) are mammalian flavoenzyme, which catalyze the oxidative deamination of several neurotransmitters like norepinephrine, dopamine, tyramine, serotonin, and some other amines. The oxidative deamination produces several harmful side products like ammonia, peroxides, and aldehydes during the biochemical reaction. The concentration of biochemical neurotransmitter alteration in the brain by MAO is directly related with several neurological disorders like Alzheimer's disease and Parkinson's disease (PD). Activated MAO also contributes to the amyloid beta (Aβ) aggregation by two successive cleft β-secretase and γ-secretase of amyloid precursor protein (APP). Additionally, activated MAO is also involved in aggregation of neurofibrillary tangles and cognitive destruction through the cholinergic neuronal damage and disorder of the cholinergic system. MAO inhibition has general anti-Alzheimer's disease effect as a consequence of oxidative stress reduction prompted by MAO enzymes. In this review, we outlined and addressed recent understanding on MAO enzymes such as their structure, physiological function, catalytic mechanism, and possible therapeutic goals in AD. In addition, it also highlights the current development and discovery of potential MAO inhibitors (MAOIs) from various chemical scaffolds.

Combining genetic and epigenetic parameters of the serotonin transporter gene in obsessive-compulsive disorder

While genetic variants have been reported to be associated with obsessive-compulsive disorder (OCD), the small effect sizes suggest that epigenetic mechanisms such as DNA methylation may also be relevant. The serotonin transporter (SLC6A4) gene has been extensively investigated in relation to OCD, since serotonin reuptake inhibitors are the pharmacological treatment of choice for the disorder. The current study set three questions: Firstly, whether the high expressing loci of the SLC6A4 polymorphisms, 5-HTTLPR + rs25531, rs25532 and rs16965628 are associated with family-based (n = 164 trios) and case-control OCD (n = 186, 152, respectively). This was also examined by a meta-analysis. Secondly, whether DNA methylation and RNA levels of the SLC6A4 differ in saliva and blood of a subset of samples from pediatric and adult OCD patients and matched controls. And lastly, whether morning awakening cortisol levels correlate with the above. A meta-analysis confirmed the association of the L_A-allele with OCD (OR = 1.21, p = 0.00018), maintaining significance in the early-onset OCD subgroup (OR = 1.21, p = 0.022). There was no association between rs25532 or rs16965628 and OCD. Our preliminary data showed that SLC6A4 DNA methylation levels in an amplicon located at the beginning of the first intron were significantly higher in the saliva of pediatric OCD patients compared to controls and adult patients with OCD, but no alterations in RNA levels or in polymorphism interactions were observed. Morning awakening salivary cortisol levels positively correlated with methylation levels, and negatively correlated with RNA levels. This study further supports the involvement of the SLC6A4 gene in OCD through both genetic and epigenetic mechanisms. This finding needs to be explored further in an independent large sample.

Explorative results from multistep screening for potential genetic risk loci of Alzheimer's disease in the longitudinal VITA study cohort

Alzheimer's disease (AD) is a neurodegenerative disorder that preferentially affects individuals of advanced age. Heritability estimates for AD range between 60 and 80%, but only few genetic risk factors have been identified so far. In the present explorative study, we aimed at characterizing the genetic contribution to late-onset AD in participants of the Vienna Transdanube Aging (VITA) longitudinal birth cohort study in a two-step approach. First, we performed a genome-wide screen of pooled DNA samples (n = 588) to identify allele frequency differences between AD patients and non-AD individuals using life-time diagnoses made at the age of 80 (t = 60 months). This analysis suggested a high proportion of brain-expressed genes required for cell adhesion, cell signaling and cell morphogenesis, and also scored in known AD risk genes. In a second step, we confirmed associations using individual genotypes of top-ranked markers examining AD diagnoses as well as the dimensional scores: FULD and MMSE determined up to the age of 82.5 (t = 90 months). Taken together, our study proposes genes ANKS1B, ENST00000414107, LOC100505811, SLC22A14, QRFPR, ZDHHC8P1, ADAMTS3 and PPFIA1 as possible new candidates involved in the etiology of late-onset AD, with further research being needed to clarify their exact roles.

Platelets, a reliable source for peripheral Alzheimer's disease biomarkers?

Peripheral biomarkers play an indispensable role in quick and reliable diagnoses of any kind of disease. With the population ageing, the number of people suffering from age-related diseases is expected to rise dramatically over the coming decades. In particular, all types of cognitive deficits, such as Alzheimer's disease, will increase. Alzheimer's disease is characterised mainly by coexistence of amyloid plaques and neurofibrillary tangles in brain. Reliable identification of such molecular characteristics antemortem, however, is problematic due to restricted availability of appropriate sample material and definitive diagnosis is only possible postmortem. Currently, the best molecular biomarkers available for antemortem diagnosis originate from cerebrospinal fluid. Though, this is not convenient for routine diagnosis because of the required invasive lumbar puncture. As a consequence, there is a growing demand for additional peripheral biomarkers in a more readily accessible sample material. Blood platelets, due to shared biochemical properties with neurons, can constitute an attractive alternative as discussed here. This review summarises potential platelet Alzheimer's disease biomarkers, their role, implication, and alteration in the disease. For easy comparison of their performance, the Hedge effect size was calculated whenever data were available.

Monoamine oxidase inhibitors: promising therapeutic agents for Alzheimer's disease (Review)

Activated monoamine oxidase (MAO) has a critical role in the pathogenesis of Alzheimer's disease (AD), including the formation of amyloid plaques from amyloid β peptide (Aβ) production and accumulation, formation of neurofibrillary tangles, and cognitive impairment via the destruction of cholinergic neurons and disorder of the cholinergic system. Several studies have indicated that MAO inhibitors improve cognitive deficits and reverse Aβ pathology by modulating proteolytic cleavage of amyloid precursor protein and decreasing Aβ protein fragments. Thus, MAO inhibitors may be considered as promising therapeutic agents for AD.

Investigation of association of serotonin transporter and monoamine oxidase-A genes with Alzheimer's disease and depression in the VITA study cohort: a 90-month longitudinal study

Alzheimer's disease (AD) and depression (DE) are common psychiatric disorders strongly intertwined with one another. Nevertheless, etiology and early diagnosis of the disorders are still elusive. Several genetic variations have been suggested to associate with AD and DE, particularly in genes involved in the serotonergic system such as the serotonin transporter (SERT/SLC6A4), responsible for the removal from the synaptic cleft, and the monoamine-oxidase-A (MAOA), responsible for the presynaptic degradation of serotonin. Here, we attempt to characterize this pleiotropic effect for the triallelic SERT gene-linked polymorphic region (5HTTLPR) and for the MAOA-uVNTR, in participants in the Vienna-Transdanube-Aging (VITA)-study. The VITA-study is a community-based longitudinal study following a birth cohort (75 years old at baseline examination, n = 606) from Vienna for a period of 90 months with a regular follow-up interval of 30 months. Our main finding, confirming previous reports, is that the 5HTTLPR S-allele is a risk allele for DE (OR = 1.55 CI 95% 1.03-2.32) and its carriers had a steeper increase in SGDS sum score. No association to AD was found. MAOA-uVNTR did not associate with either AD or DE. However, in AD MAOA-uVNTR S-allele carriers a steeper increase of HAMD and STAI1 sum scores (P < 0.05) was observed. Although the VITA-study cohort is rather small with low power to detect gene alterations, the uniqueness of this very thoroughly investigated and homogenous cohort strengthens the results through exceptional data collection. Still, reinvestigation in a larger cohort similar to this, as well as a meta-analysis, is important to confirm these results.

Blood markers of oxidative stress in Alzheimer's disease

Alzheimer′s disease (AD) represents a highly common form of dementia, but can be diagnosed in the earlier stages before dementia onset. Early diagnosis is crucial for successful therapeutic intervention. The introduction of new diagnostic biomarkers for AD is aimed at detecting underlying brain pathology. These biomarkers reflect structural or biochemical changes related to AD. Examination of cerebrospinal fluid has many drawbacks; therefore, the search for sensitive and specific blood markers is ongoing. Investigation is mainly focused on upstream processes, among which oxidative stress in the brain is of particular interest. Products of oxidative stress may diffuse into the blood and evaluating them can contribute to diagnosis of AD. However, results of blood oxidative stress markers are not consistent among various studies, as documented in this review. To find a specific biochemical marker for AD, we should concentrate on specific metabolic products formed in the brain. Specific fluorescent intermediates of brain lipid peroxidation may represent such candidates as the composition of brain phospholipids is unique. They are small lipophilic molecules and can diffuse into the blood stream, where they can then be detected. We propose that these fluorescent products are potential candidates for blood biomarkers of AD.

Different effects of soluble and aggregated amyloid β42 on gene/protein expression and enzyme activity involved in insulin and APP pathways

Although Alzheimer's dementia (AD) is not characterised any longer simply as the accumulation and deposition of amyloid beta (Aβ) peptides and hyperphosphorylation of tau proteins within the brain, excessive Aβ(42) deposition is still considered to play a major role in this illness. Aβ are able to adopt many differently aggregate forms, including amyloid fibrils as well as nonfibrillar structures (soluble Aβ(42) oligomers). It is not well-established that which Aβ(42) state is most responsible for AD or why. We wanted to verify which effects Aβ(42) oligomers and aggregated peptides have on gene expression, protein level and enzyme activity of insulin and amyloid precursor protein (APP) pathways in vitro. Human neuroblastoma cells (SH-SY5Y) were treated with varying concentrations of soluble and aggregated Aβ(42). Treatment effects on β-secretase (BACE), glycogen synthase kinase 3α (GSK3α), glycogen synthase kinase 3β (GSK3β), phosphatidylinositol-3 kinase (PI-3K), insulin-degrading enzyme (IDE), insulin-receptor substrate 1 (IRS1), insulin receptor (INSR) and monoamine oxidase B (MAO-B) were investigated via quantitative-PCR, western blot, ELISA and enzyme activity assay. We could find different effects of soluble and aggregated peptides especially on gene/protein expression of GSK3β and INSR and on GSK3β and MAO-B activity. Soluble peptides showed significant effects leading to increased gene expression and protein amount of GSK3β and to decreased level of gene and protein expression of INSR. MAO-B activity was enhanced after treatment with aggregated peptides and strongly inhibited after soluble Aβ(42) treatment. Our data might provide insights into selective effects of specific forms of Aβ(42) aggregates in AD.

Comparative platelet proteome analysis reveals an increase of monoamine oxidase-B protein expression in Alzheimer's disease but not in non-demented Parkinson's disease patients

Monoamine oxidase-B (Mao-B) catalysing the breakdown of the neurotransmitter dopamine, is known to be involved in the pathophysiology of Parkinson's (PD) and Alzheimer's disease (AD). Increased brain Mao-B activity is associated with AD. This alteration can also be seen in platelets, albeit the cause has hitherto remained elusive. To gain a deeper understanding of the etiology of AD, the platelet proteome was characterised, (2D DIGE pH6-9, including Mao-B) from 150 individuals: 34 AD, 13 vascular dementia, 15 non-demented PD patients, 49 matched controls, 18 oldest old and 21 young individuals. One significant change was noted after applying false discovery rate with the upregulation of the Mao-B expression (30% adjusted P value<0.001; effect size 1.31) in AD compared to age- and sex-matched controls. In contrast, Mao-B levels were unchanged in PD to matched controls. Western blot and mRNA analyses verified these findings. Moreover, Mao-B concentration correlated with age in the cognitive healthy individuals (r=0.53; P<0.001) and PD patients but not in those suffering from AD (r=-0.03; P=0.874). Mao-B activity correlated with the increased Mao-B protein expression in AD (r=0.81; P=0.016). We suggest that Mao-B platelet protein level may serve as a biomarker for age-related dementia, especially AD.

Alteration of the pro-oxidant xanthine oxidase (XO) in the thalamus and occipital cortex of patients with schizophrenia

OBJECTIVES

Mounting evidence shows that oxidative stress (OS) and the purine/adenosine system play a key role in the pathophysiology of schizophrenia. Lately, our group pointed out that not only antioxidants, but also the prooxidant system plays an important role in neuro-psychiatric disorders. Xanthine oxidase (XO) is an enzyme of special interest in this context, since it acts as a prooxidant, but its main product is a vastly important antioxidant, uric acid (UA). Furthermore, XO plays major part in the purine/adenosine metabolism, which has been hypothesised to play a role in schizophrenia as well.

METHODS

We examined the activity of XO in the striato-cortico-limbic system of schizophrenic patients (SP) and controls using a commercially available activity assay.

RESULTS

We found decreased activity of XO in the occipital cortex and thalamus of patients with psychosis. Furthermore, XO shows a significant positive correlation with chlorpromazine equivalents in the putamen and the temporal cortex.

CONCLUSIONS

Nevertheless, our results might suggest a downregulation of cellular defence mechanisms in schizophrenia in several brain regions, which could account for neuronal alterations which have been described before. This demonstrates that more research is needed to fully understand the role of the complex enzyme XO in the pathophysiology of schizophrenia.

Disorder-specific effects of polymorphisms at opposing ends of the Insulin Degrading Enzyme gene

Background

Insulin-degrading enzyme (IDE) is the ubiquitously expressed enzyme responsible for insulin and amyloid beta (Aβ) degradation. IDE gene is located on chromosome region 10q23-q25 and exhibits a well-replicated peak of linkage with Type 2 diabetes mellitus (T2DM). Several genetic association studies examined IDE gene as a susceptibility gene for Alzheimer's disease (AD), however with controversial results.

Methods

We examined associations of three IDE polymorphisms (IDE2, rs4646953; IDE7, rs2251101 and IDE9, rs1887922) with AD, Aβ₄₂ plasma level and T2DM risk in the longitudinal Vienna Transdanube Aging (VITA) study cohort.

Results

The upstream polymorphism IDE2 was found to influence AD risk and to trigger the Aβ₄₂ plasma level, whereas the downstream polymorphism IDE7 modified the T2DM risk; no associations were found for the intronic variant IDE9.

Conclusions

Based on our SNP and haplotype results, we delineate the model that IDE promoter and 3' untranslated region/downstream variation may have different effects on IDE expression, presumably a relevant endophenotype with disorder-specific effects on AD and T2DM susceptibility.

Genetic variation in the choline O-acetyltransferase gene in depression and Alzheimer's disease: the VITA and Milano studies

Linkage studies point to the long arm of chromosome 10 being a susceptibility region for Alzheimer's disease (AD). Additionally, the gene choline O-acetyltransferase (CHAT) located on chromosome 10 was discussed for conveying risk towards AD, but the results are ambiguous. We examined a possible association of nineteen single-nucleotide polymorphisms (SNPs) in the CHAT gene in a longitudinal cohort study, the Vienna Tansdanube Aging (VITA)-study, in which all subjects were 75 years old at baseline. For replication, we used a more heterogeneous case-control sample from Milano with early and late AD. Nominal allelic and genotypic associations with AD risk in the cross-sectional VITA sample were found for rs3810950 (p = 0.038 for genotype, OR = 1.66 95% CI 1.03-2.68, p = 0.052 allele-wise). When combining both VITA- and Milano study rs3810950 was significantly associated with AD (p(combined) = 0.01634; power = 82%). This association was highly significant for APOEε4 carriers (p = 0.009 for genotype, OR = 3.21 95% CI 1.43-7.19 p = 0.007 allele-wise). Furthermore, an association of rs1880676 with AD was specific to carriers of the APOEε4 risk allele (p = 0.008, genotype; OR = 3.47 95% CI 1.50-8.01 p = 0.005 allele-wise). For depressive symptoms, we found a nominally significant association of rs3810950 with minor and major depression (p = 0.023, genotype; p = 0.008, allele). Applying Benjamini and Hochberg correction these associations could not be confirmed and also not be replicated in the more heterogeneous Milano sample. While our data therefore do not seem to support a major role for CHAT genetic variation in geriatric depression and AD, there might be a minor contribution in geriatric patients with depression and late onset AD, in particular those carrying the APOEε4 genotype.

Alzheimer disease-related presenilin-1 variants exert distinct effects on monoamine oxidase-A activity in vitro

Monoamine oxidase-A (MAO-A) has been associated with both depression and Alzheimer disease (AD). Recently, carriers of AD-related presenilin-1 (PS-1) alleles have been found to be at higher risk for developing clinical depression. We chose to examine whether PS-1 could influence MAO-A function in vitro. Overexpression of selected AD-related PS-1 variants (wildtype, Y115H, ΔEx9 and M146V) in mouse hippocampal HT-22 cells affects MAO-A catalytic activity in a variant-specific manner. The ability of the PS-1 substrate-competitor DAPT to induce MAO-A activity in cells expressing either PS-1 wildtype or PS-1(M146V) suggests the potential for a direct influence of PS-1 on MAO-A function. In support of this, we were able to co-immunoprecipitate MAO-A with FLAG-tagged PS-1 wildtype and M146V proteins. This potential for a direct protein-protein interaction between PS-1 and MAO-A is not specific for HT-22 cells as we were also able to co-immunoprecipitate MAO-A with FLAG-PS-1 variants in N2a mouse neuroblastoma cells and in HEK293 human embryonic kidney cells. Finally, we demonstrate that the two PS-1 variants reported to be associated with an increased incidence of clinical depression [e.g., A431E and L235V] both induce MAO-A activity in HT-22 cells. A direct influence of PS-1 variants on MAO-A function could provide an explanation for the changes in monoaminergic tone observed in several neurodegenerative processes including AD. The ability to induce MAO-A catalytic activity with a PS-1/γ-secretase inhibitor should also be considered when designing secretase inhibitor-based therapeutics.

Behavioral outcomes of monoamine oxidase deficiency: preclinical and clinical evidence

Monoamine oxidase (MAO) isoenzymes A and B are mitochondrial-bound proteins, catalyzing the oxidative deamination of monoamine neurotransmitters as well as xenobiotic amines. Although they derive from a common ancestral progenitor gene, are located at X-chromosome and display 70% structural identity, their substrate preference, regional distribution, and physiological role are divergent. In fact, while MAO-A has high affinity for serotonin and norepinephrine, MAO-B primarily serves the catabolism of 2-phenylethylamine (PEA) and contributes to the degradation of other trace amines and dopamine. Convergent lines of preclinical and clinical evidence indicate that variations in MAO enzymatic activity--due to either genetic or environmental factors--can exert a profound influence on behavioral regulation and play a role in the pathophysiology of a large spectrum of mental and neurodegenerative disorders, ranging from antisocial personality disorder to Parkinson's disease. Over the past few years, numerous advances have been made in our understanding of the phenotypical variations associated with genetic polymorphisms and mutations of the genes encoding for both isoenzymes. In particular, novel findings on the phenotypes of MAO-deficient mice are highlighting novel potential implications of both isoenzymes in a broad spectrum of mental disorders, ranging from autism and anxiety to impulse-control disorders and ADHD. These studies will lay the foundation for future research on the neurobiological and neurochemical bases of these pathological conditions, as well as the role of gene × environment interactions in the vulnerability to several mental disorders.

Increased xanthine oxidase in the thalamus and putamen in depression

A growing body of literature suggests persistent and selective structural changes in the cortico-limbic-thalamic-striatal system in patients with recurrent depressive disorder (DD). Oxidative stress is thought to play a key role in these processes. So far, the main scientific focus has been on antioxidant enzymes in this context. For the first time, this proof of concept study examines the activity of the free radicals producing the enzyme, xanthine oxidase (XO), directly in the cortico-limbic-thalamic-striatal system of patients with recurrent depression. The activity of XO was ascertained in the cortico-limbic-thalamic-striatal regions in post-mortem brain tissue of patients with recurrent depressive episodes and individuals without any neurological or psychiatric history (7/7). We measured the XO activity in following brain areas: hippocampus, regio entorhinalis, thalamus, putamen and caudate nucleus. In this study, we report a significant increase of XO activity in the thalamus and the putamen of patients with depression. Our findings contribute to the growing body of evidence suggesting that oxidative stress plays a pivotal role in certain brain areas in recurrent depressive disorder.

Invivo antioxidant status: a putative target of antidepressant action

Oxidative stress is a critical route of damage in various psychological stress-induced disorders, such as depression. Antidepressants are widely prescribed to treat these conditions; however, few animal studies have investigated the effect of these drugs on endogenous antioxidant status in the brain. The present study employed a 21-day chronic regimen of random exposure to restraint stress to induce oxidative stress in brain, and behavioural aberrations, in rodents. The forced swimming (FST) and sucrose preference tests were used to identify depression-like phenotypes, and reversal in these indices indicated the effectiveness of treatment with fluoxetine (FLU; 20 mg/kg/day, p.o.; selective serotonin reuptake inhibitor), imipramine (IMI; 10 mg/kg/day, p.o.; tricyclic antidepressant) and venlafaxine (VEN; 10 mg/kg/day, p.o.; dual serotonin/norepinephrine reuptake inhibitor) following restraint stress. The antioxidant status was investigated in the brain of these animals. The results evidenced a significant recovery in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), glutathione reductase (GR) and glutathione (GSH) levels by antidepressant treatments following a restraint stress-induced decline of these parameters. The severely accumulated lipid peroxidation product malondialdehyde (MDA) and protein carbonyl contents in stressed animals were significantly normalized by antidepressant treatments. The altered oxidative status is implicated in various aspects of cellular function affecting the brain. Thus, it is possible that augmentation of in vivo antioxidant defenses could serve as a convergence point for multiple classes of antidepressants as an important mechanism underlying the neuroprotective pharmacological effects of these drugs observed clinically in the treatment of various stress disorders. Consequently, pharmacological modulation of stress-induced oxidative damage as a possible stress-management approach should be an important avenue of further research.

Genetic risk factors and markers for Alzheimer's disease and/or depression in the VITA study

OBJECTIVES

In ageing population, both Alzheimer's disease (AD) and depression are common. Significant depressive symptoms are often co-morbid with cognitive impairment and dementia. In this study, we attempted to find various factors and markers for both AD and depression in a longitudinal cohort, the Vienna-Transdanube-Aging (VITA)-study.

METHODS

The VITA-Study consisted of 305 healthy subjects, 174 subjects with depression only, 55 subjects diagnosed with AD only and 72 subjects with depression as well as AD. Associations between AD and/or depression to gene polymorphisms APO E (epsilon4), choline acetyltransferase (ChAT) 4G to A, serotonin-transporter gene promoter-length, dopamine-D4-receptor, ciliary-neurotrophic-factor-null mutation and brain-derived neurotrophic factor (C270T) and to various known factors were analyzed.

RESULTS

AD and depression were significant associated. Significant risk factors found for AD were low education, low folic acid and depressive-symptoms, while for depression were low education and higher nonsteroidal anti-inflammatory drugs (NSAID) consume. Moreover, the ChAT polymorphism associated significant to depression. Gender, education, and ChAT significantly associated with the combination AD and/or depression.

CONCLUSION

Such studies must be conducted cautiously, as co-morbidities and gene-environmental-social influences may sway the results dramatically. We found in the VITA-study significant association between depression and AD and between ChAT polymorphism and depression.

Association of major depressive disorder with serum myeloperoxidase and other markers of inflammation: a twin study

BACKGROUND

Major depressive disorder (MDD) has been linked to inflammation, but this association may be due to common precursors to both depression and inflammation. Myeloperoxidase (MPO) is an inflammatory enzyme produced by activated leukocytes that predicts risk of coronary heart disease. We sought to examine whether MPO and other markers of inflammation are associated with MDD and whether the association is confounded by genetic or other shared familial factors.

METHODS

We examined 178 monozygotic and dizygotic middle-aged male twin pairs. We assessed MDD with the Structured Clinical Interview for DSM-IV. Blood markers of inflammation included MPO, interleukin-6, white blood cell count, C-reactive protein, tumor necrosis factor (TNF)-alpha, the TNF-alpha soluble receptor II, and fibrinogen. Analyses were conducted in the overall sample and among 67 twin pairs discordant for MDD using mixed effects regression.

RESULTS

Twins with a history of MDD had 32% higher levels of MPO (p < .0001); this difference persisted after adjusting for other risk factors. Among dizygotic MDD-discordant twin pairs, twins with MDD had 77% higher MPO than their brothers without MDD, after adjusting for other factors (p < .0001). In contrast, no significant association was found in monozygotic twins (p = .13). Similar, but weaker, associations were found between MDD and other inflammatory biomarkers.

CONCLUSIONS

Myeloperoxidase is a useful biomarker of immune activation in MDD. However, the association between inflammation and MDD is largely due to common genetic liability. Our results are consistent with the hypothesis that genes promoting inflammation are involved in the pathogenesis of MDD.

Evidence for oxidative stress in the frontal cortex in patients with recurrent depressive disorder--a postmortem study

Prefrontal cortical (PFC) and hippocampal (HI) volume reductions have been consistently found in patients with recurrent depressive disorder (DD). Here we examine the possibility that oxidative stress, widely implicated in neuronal cell damage, may contribute to these brain structural changes. We compared manganese (Mn) and copper/zinc (Cu/Zn) superoxide dismutase (SOD) coenzyme concentrations in postmortem PFC and hippocampal brain tissue from 7 patients with DD and 7 neuropsychiatrically healthy controls using sandwich-type enzyme-linked immunosorbent assay (ELISA) technique. The concentration of Cu/Zn-SOD was significantly increased in the PFC but not in the hippocampus of patients. There was no significant change in Mn-SOD enzyme concentration in either region. Our findings contribute to the growing body of evidence implicating oxidative stress in the pathophysiology of depressive disorder.

Association study of BDNF and CNTF polymorphism to depression in non-demented subjects of the "VITA" study

BACKGROUND

Neurotrophic factors are known to play an important role in the survival and differentiation of many types of neurons during development. Both brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF) may act cooperatively in modulating the development and functioning of synapses. Both these neurotrophic factors were intensely investigated with regard to depression without conclusive results.

METHODS

We have investigated the possible use of both CNTF null-mutation and BDNF polymorphism C270T as biomarkers for depression in the Vienna Transdanube Aging (VITA) study. The VITA is a prospective community-based cohort study of all 75 years old inhabitants of a geographical region of Vienna.

RESULTS

We found no association between CNTF null-mutation and BDNF C270T polymorphism to any depressive symptoms after exclusion of demented subjects.

CONCLUSION

These results call in question the hypothesis that either BDNF or CNTF can be used as molecular markers for depression or late onset depression in the elderly.