Methylenetetrahydrofolate Reductase A1298C Polymorphism and Major Depressive Disorder

Lack of association between VNTR variant of the circadian gene (PER3) and major depressive disorder in a sample of a Turkish population

Major depressive disorder (MDD), which is a prevalent psychiatric disorder, is characterized by sleep-wake disturbances. An underlying circadian rhythm disorder mainly may cause these disturbances. The study presented here was designed to investigate the existence of Period Circadian Regulator 3 (PER3) gene VNTR variant in MDD patients in Turkish population. A sample of 118 patients with MDD and 150 healthy volunteers were included in the study. The PER3 VNTR genotyping was performed on DNA by polymerase chain reaction (PCR) using specific primers. The prevalence rates of genotypes of 5/5, 5/4, and 4/4 profiles for the PER3 variant were 30.5%, 55.9%, and 13.6%, respectively, in patients with MDD, and 23.3%, 57.3%, and 19.3%, respectively in the control group. No significant difference was observed between the two groups in terms of either genotype distributions or allele frequencies of the VNTR variant of the PER3 gene (p > 0.05). There was no statistically significant association between the patients and the controls in terms of 5/5 + 4/5 versus 4/4 and 5/5 versus 4/5 + 4/4 (p > 0.05). The present results suggest that the PER3 VNTR variant was not associated with MDD in the Turkish population. However, further studies with other gene variants in different ethnic populations are needed to address the exact role of this variant in MDD.

Development of a genetic risk score for obesity predisposition evaluation

Obesity is a major public health issue resulting from an interaction between genetic and environmental factors. Genetic risk scores (GRSs) are useful to summarize the effects of many genetic variants on obesity risk. In this study, we aimed to assess the association of previously well-studied genetic variants with obesity and develop a genetic risk score to anticipate the risk of obesity development in the Iranian population. Among 968 participants, 599 (61.88%) were obese, and 369 (38.12%) were considered control samples. After genotyping, an initial screening of 16 variants associated with body mass index (BMI) was performed utilizing a general linear model (p < 0.25), and seven genetic variants were selected. The association of these variants with obesity was examined using a multivariate logistic regression model (p < 0.05), and finally, five variants were found to be significantly associated with obesity. Two gene score models (weighted and unweighted), including these five loci, were constructed. To compare the discriminative power of the models, the area under the curve was calculated using tenfold internal cross-validation. Among the studied variants, ADRB3 rs4994, FTO rs9939609, ADRB2 rs1042714, IL6 rs1800795, and MTHFR rs1801133 polymorphisms were significantly associated with obesity in the Iranian population. Both of the constructed models were significantly associated with BMI (p < 0.05) and the area under the mean curve of the weighted GRS and unweighted GRS were 70.22% ± 0.05 and 70.19% ± 0.05, respectively. Both GRSs proved to predict obesity and could potentially be utilized as genetic tools to assess the obesity predisposition in the Iranian population. Also, among the studied variants, ADRB3 rs4994 and FTO rs9939609 polymorphisms have the highest impacts on the risk of obesity.

Association Between MTHFR rs17367504 Polymorphism and Major Depressive Disorder in Taiwan: Evidence for Effect Modification by Exercise Habits

BACKGROUND/AIM

Recent studies reported that folate supplementation has beneficial effects on major depression. The Methylenetetrahydrofolate reductase (MTHFR) enzyme is crucial in folate metabolism. This population-based study examined the association between MTHFR rs17367504 polymorphism and major depressive disorder based on exercise habits.

METHODS

Taiwan Biobank (TWB) provided demographic and genotype data between 2008 and 2015. The biobank participants were Taiwanese aged 30 to 70. Data on major depressive disorder (MDD) were obtained from the National Health Insurance Research Database (NHIRD).

RESULTS

A total of 636 individuals were identified with MDD, whereas 17,298 individuals were considered controls. The associations of MTHFR rs17367504 and exercise with MDD risk were estimated using logistic regression models. The distribution of MTHFR rs17367504 genotype frequencies differed significantly between the MDD and control groups. We found that, compared with the AA genotype, the GG genotype was associated with a significantly increased risk of MDD [adjusted odds ratio (aOR), 1.76; 95% confidence interval (CI), 1.05-2.94; p = 0.033]. We found an interaction (p = 0.04) between rs17367504 and exercise, a well-known protective factor for MDD. A substantial increase in the risk of MDD was found among those with GG genotypes who did not exercise (aOR, 2.93; 95% CI, 1.66-5.17; p < 0.001).

CONCLUSIONS

Our findings indicate that MDD is related to MTHFR rs17367504 and exercise, though the mechanisms remain to be determined.

Opicapone Protects Against Hyperhomocysteinemia-Induced Increase in Blood-Brain Barrier Permeability

Hyperhomocysteinemia (HHcy)-related brain vascular disorders and brain endothelial dysfunction are important characteristics of the pathogeneses of subarachnoid hemorrhage and stroke. Upregulated homocysteine (Hcy) can impair the integrity of the blood-brain barrier (BBB). Opicapone has been recently licensed for the management of Parkinson's disease (PD); however, it is unknown whether it possesses a protective effect in brain vessels against HHcy. To investigate the beneficial effects of Opicapone on BBB permeability against HHcy, we carried out both in vivo and in vitro experiments. Mice were allocated into four groups: the Control, Opicapone, HHcy, and HHcy + Opicapone. Interestingly, we found that the administration of Opicapone attenuated the increased BBB permeability in Hcy-treated mice, as determined by sodium fluorescein staining. The immunofluorescence staining showed that Opicapone prevented homocysteine-induced reduction of claudin-2 in the mice cortices. The in situ zymography assay revealed that Opicapone suppressed homocysteine-increased matrix metalloproteinases (MMPs) activity in the cortices. In bEnd.3 brain endothelial cells, Opicapone treatment ameliorated homocysteine-induced lactate dehydrogenase (LDH) release and expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). Furthermore, Opicapone alleviated homocysteine-induced decrease in claudin-2 level in bEnd.3 cells. In summary, our results show that Opicapone protects against HHcy-induced BBB permeability by reducing the expression and gelatinase activity of MMPs, and increasing the expression of claudin-2.

Association of Two Methylenetetrahydrofolate Reductase Polymorphisms (rs1801133, rs1801131) with the Risk of Type 2 Diabetes in South-East of Iran

BACKGROUND

DNA methylation has been linked to the development and progression of multiple disorders including T2D. One significant enzyme involved in DNA methylation is methylene tetrahydrofolate reductase (MTHFR). This study was designed to evaluate the association between rs1801133 and rs1801131 polymorphisms, located in the MTHFR, and T2D in an Iranian population.

METHODS

Blood samples from 151 patients with T2D and 136 healthy individuals were collected and DNA was extracted using the salting out method. Variants were genotyped using amplification tetrarefractory mutation system-polymerase chain reaction analysis. The data were analyzed via independent sample t-test and x2 tests.

RESULTS

The rs1801131 A/C polymorphism significantly increased the risk of T2D in codominant heterozygous AC (P=0.008), homozygous CC (P=0.01), and recessive CC (P=0.001) genotypes. Significant correlations were found regarding rs1801133 T/C gene polymorphism and the risk of T2D in codominant heterozygous TC (P=0.001), homozygote CC (P=0.001), and recessive CC (P=0.0001) models. The presence of the C allele is a potential risk factor for T2D for rs1801133 T/C (P=0.001) and rs1801131 A/C (P=0.04) polymorphisms.

CONCLUSION

Both the rs1801133 T/C and rs1801131 A/C MTHFR polymorphisms significantly increased the risk of T2D in our population. Further studies in other ethnicities are necessary to verify our findings.

5-HTTLPR and MTHFR 677C>T polymorphisms and response to yoga-based lifestyle intervention in major depressive disorder: A randomized active-controlled trial

BACKGROUND

There is growing evidence suggesting that both genetic and environmental factors modulate treatment outcome in, a highly heterogeneous, major depressive disorder (MDD). 5-HTTLPR variant of the serotonin transporter gene (SLC6A4) and MTHFR 677C>T polymorphisms have been linked to the pathogenesis of MDD, and antidepressant treatment response. The evidence is lacking on the clinical utility of yoga in patients with MDD who have 5-HTTLPR and MTHFR 677C>T polymorphisms and less likely to respond to medications (SSRIs).

AIMS

We aimed to examine the impact of YBLI in those who have susceptible 5-HTTLPR and MTHFR 677C>T polymorphisms and are less likely to drug therapy with SSRIs.

SETTINGS AND DESIGN

In a 12 week randomized active-controlled trial, MDD patients (n = 178) were randomized to receive YBLI or drug therapy.

METHODS

Genotyping was conducted using PCR-based methods. The clinical remission was defined as BDI-II score ≤ 9.

STATISTICAL ANALYSIS USED

An intent-to-treat analysis was performed, and the association of genotype with treatment remission consisted of the logistic regression model. A P value of <0.05 was considered statistically significant.

RESULTS

Multivariate logistic regression models for remission including either 5-HTTLPR or MTHFR 677C>T genotypes showed statistically significant odds of remission in YOGA arm vs. DRUG arm. Neither 5-HTTLPR nor MTHFR 677C>T genotype showed any influence on remission to YBLI (P = 0.73 and P = 0.64, respectively). Further analysis showed childhood adversity interact with 5-HTTLPR and MTHFR 677C>T polymorphisms to decrease treatment response in DRUG treatment arm, but not in YOGA arm.

CONCLUSIONS

YBLI provides MDD remission in those who have susceptible 5-HTTLPR and MTHFR 677C>T polymorphisms and are resistant to SSRIs treatment. YBLI may be therapeutic for MDD independent of heterogeneity in its etiopathogenesis.