Role of DRD2 and ALDH2 genes in bipolar II disorder with and without comorbid anxiety disorder

Genetic Correlates as a Predictor of Bariatric Surgery Outcomes after 1 Year

This study analyzed genetic risk assessments in patients undergoing bariatric surgery to serve as a predictive factor for weight loss parameters 1 year after the operation. Thirty (30) patients were assessed for Genetic Addiction Risk Severity (GARS), which analyzes neurogenetic polymorphisms involved in addiction and reward deficiency. Genetic and psychosocial data collected before the operation were correlated with weight loss data, including changes in weight, body mass index (BMI), and percent of expected weight loss (%EWL). Results examined correlations between individual gene risk alleles, 1-year body weight data, and psychosocial trait scores. Spearman's correlations revealed that the OPRM1 (rs1799971) gene polymorphism had significant negative correlation with 1-year weight (rs = -0.4477, p < 0.01) and BMI (rs = -0.4477, p < 0.05). In addition, the DRD2 risk allele (rs1800497) was correlated negatively with BMI at 1 year (rs = -0.4927, p < 0.05), indicating that one risk allele copy was associated with lower BMI. However, this allele was positively correlated with both ∆Weight (rs = 0.4077, p < 0.05) and %EWL (rs = 0.5521, p < 0.05) at 1 year post-surgery. Moreover, the overall GARS score was correlated with %EWL (rs = 0.4236, p < 0.05), ∆Weight (rs = 0.3971, p < 0.05) and ∆BMI (rs = 0.3778, p < 0.05). Lastly, Food Cravings Questionnaire (FCQ) scores were negatively correlated with %EWL (rs = -0.4320, p < 0.05) and ∆Weight at 1 year post-surgery (rs = -0.4294, p < 0.05). This suggests that individuals with a higher genetic addiction risk are more responsive to weight loss treatment, especially in the case of the DRD2 polymorphism. These results should translate clinically to improve positivity and attitude related to weight management by those individuals born with the risk alleles (rs1800497; rs1799971).

Researching Mitigation of Alcohol Binge Drinking in Polydrug Abuse: KCNK13 and RASGRF2 Gene(s) Risk Polymorphisms Coupled with Genetic Addiction Risk Severity (GARS) Guiding Precision Pro-Dopamine Regulation

Excessive alcohol intake, e.g., binge drinking, is a serious and mounting public health problem in the United States and throughout the world. Hence the need for novel insights into the underlying neurobiology that may help improve prevention and therapeutic strategies. Therefore, our group employed a darkness-induced alcohol intake protocol to define the reward deficiency domains of alcohol and other substance use disorders in terms of reward pathways' reduced dopamine signaling and its restoration via specifically-designed therapeutic compounds. It has been determined that KCNK13 and RASGRF2 genes, respectively, code for potassium two pore domain channel subfamily K member 13 and Ras-specific guanine nucleotide-releasing factor 2, and both genes have important dopamine-related functions pertaining to alcohol binge drinking. We present a hypothesis that identification of KCNK13 and RASGRF2 genes' risk polymorphism, coupled with genetic addiction risk score (GARS)-guided precision pro-dopamine regulation, will mitigate binge alcohol drinking. Accordingly, we review published reports on the benefits of this unique approach and provide data on favorable outcomes for both binge-drinking animals and drunk drivers, including reductions in alcohol intake and prevention of relapse to drinking behavior. Since driving under the influence of alcohol often leads to incarceration rather than rehabilitation, there is converging evidence to support the utilization of GARS with or without KCNK13 and RASGRF2 risk polymorphism in the legal arena, whereby the argument that "determinism" overrides the "free will" account may be a plausible defense strategy. Obviously, this type of research is tantamount to helping resolve a major problem related to polydrug abuse.

Impact of mitochondrial aldehyde dehydrogenase 2 on cognitive impairment in the AD model mouse

Alzheimer's disease (AD) is one of the major life-threatening diseases for the elderly because neither pathogenesis nor effective treatment is available. Mitochondrial aldehyde dehydrogenase 2 (ALDH2) has been shown to reduce the cell-damaging aldehydes in response to reactive oxygen species (ROS). However, whether it plays a role in AD remains elusive. In the present study, we found that ALDH2 overexpression significantly improved the cognitive function of the AD mouse. Behavioral analyses of ALDH2-overexpressing APP/PS1 AD mice showed that the learning and cognitive abilities were significantly higher in these mice than in the control group APP/PS1 mice. Further open-field behavior experiments showed the same results. At the cellular level, ALDH2 protects nerve cells. HT22 cells were challenged with Aβ to establish an AD cell model, in the presence or absence of the ALDH2 activator Alda-1 and ALDH2 inhibitor Daidzin. Incubation with 50 μM Aβ for 24 h significantly reduced HT22 cell survival and cell viability, the effects of which were attenuated by the ALDH2 activator Alda-1 (50 μM). Aβ challenge promoted apoptosis and upregulated caspase3 level but suppressed Bcl-2 level, and the upregulated caspase3 level was reversed by the ALDH-2 agonist Alda-1. Aβ-induced clonal ball abnormal was reversed by Alda-1. Aβ altered the mitochondria geometry evidenced by vacuolar degeneration and membrane rupture, whereas Alda-1 changed the Aβ-induced mitochondria geometry anomalies. Moreover, superoxide anion and toxic 4-hydroxy-nonanal (4-HNE) and ROS increased by Aβ challenge were reversed by Alda-1. Meanwhile, Aβ-induced ATP reduction was reversed by Alda-1. Taken together, ALDH2 overexpression significantly improves the cognitive function of the AD mice. Furthermore, our results suggested that ALDH2 protects against Aβ hippocampal neuronal toxicity possibly through alleviating toxic aldehydes and ROS, as well as increasing ATP production to preserve mitochondrial integrity and reduce neuronal apoptosis.

Cortical mediation of relationships between dopamine receptor D2 and cognition is absent in youth at risk of bipolar disorder

Bipolar disorder is associated with cognitive deficits and cortical changes for which the developmental dynamics are not well understood. The dopamine D2 receptor (DRD2) gene has been associated with both psychiatric disorders and cognitive variability. Here we examined the mediating role of brain structure in the relationship between DRD2 genomic variation and cognitive performance, with target cortical regions selected based on evidence of association with DRD2, bipolar disorder and/or cognition from prior literature. Participants (n = 143) were aged 12-30 years and comprised 62 first-degree relatives of bipolar patients (deemed 'at-risk'), 55 controls, and 26 patients with established bipolar disorder; all were unrelated Caucasian individuals with complete data across the three required modalities (structural magnetic resonance imaging, neuropsychological and genetic data). A DRD2 haplotype was derived from three functional polymorphisms (rs1800497, rs1076560, rs2283265) associated with alternative splicing (i.e., D2-short/-long isoforms). Moderated mediation analyses explored group differences in relationships between this DRD2 haplotype, three structural brain networks which subsume the identified cortical regions of interest (frontoparietal, dorsal-attention, and ventral-attention), and three cognitive indices (intelligence, attention, and immediate memory). Controls who were homozygous for the DRD2 major haplotype demonstrated greater cognitive performance as a result of dorsal-attention network mediation. However, this association was absent in the 'at-risk' group. This study provides the first evidence of a functional DRD2-brain-cognition pathway. The absence of typical brain-cognition relationships in young 'at-risk' individuals may reflect biological differences that precede illness onset. Further insight into early pathogenic processes may facilitate targeted early interventions.

Differential core pharmacotherapy in bipolar I versus bipolar II disorder and European versus American patients not in a syndromal episode

Assess bipolar disorder subtype and treatment location effects on bipolar disorder core pharmacotherapy. Outpatients not in a syndromal episode referred to the University of Milan and Stanford University Bipolar Disorder Clinics were assessed with SCID for the fourth Edition of the Diagnostic and Statistical Manual of Mood Disorders, and the Systematic Treatment Enhancement Program for Bipolar Disorder Affective Disorders Evaluation, respectively. Prevalence and clinical correlates of antidepressant, antipsychotic, and mood stabilizer use, in aggregate and individually, were compared in bipolar I (BDI) versus II (BDII) patients in Milan/Stanford and in Milan versus Stanford patients, stratified by subtype. Milan/Stanford pooled BDI versus BDII patients significantly more often took antipsychotic (69.8 versus 44.8%), mood stabilizers (68.6 versus 57.7%), and valproate (40.1 versus 17.5%), and less often took antidepressants (23.1 versus 55.6%) and lamotrigine (9.9 versus 25.2%). Milan versus Stanford patients (stratified by bipolar disorder subtype) significantly more often took antipsychotic (BDI and BDII), antidepressants (BDII), and valproate (BDII), and less often took lamotrigine (BDI). Research regarding bipolar disorder core pharmacotherapy relationships with bipolar subtype and treatment location is warranted to enhance clinical management.

ALDH2 modulated changes in cytokine levels and cognitive function in bipolar disorder: A 12-week follow-up study

OBJECTIVES

We investigated the association of the aldehyde dehydrogenase 2 ( ALDH2) polymorphism (rs671), which is involved with the dopaminergic function, and with changes in cytokine levels and cognitive function, in a 12-week follow-up study in patients with bipolar disorder.

METHODS

Patients with a first diagnosis of bipolar disorder were recruited. Symptom severity and levels of plasma cytokines (tumor necrosis factor α, C-reactive protein, interleukin 6 and transforming growth factor β1) were examined during weeks 0, 1, 2, 4, 8 and 12. Neurocognitive function was evaluated at baseline and endpoint. The ALDH2 polymorphism genotype was determined.

RESULTS

A total of 541 patients with bipolar disorder were recruited, and 355 (65.6%) completed the 12-week follow-up. A multiple linear regression analysis showed a significant ( p = 0.000226) association between the ALDH2 polymorphism and changes in C-reactive protein levels. Different aspects of cognitive function improved in patients with different ALDH2 genotypes. Only patients with the ALDH2*1*1 genotype showed significant correlations between improvement of cognitive function and increased transforming growth factor -β1.

CONCLUSION

The ALDH2 gene might influence changes in cytokine levels and cognitive performance in patients with bipolar disorder. Additionally, changes in cytokine levels and cognitive function were correlated only in patients with specific ALDH2 genotypes.

The aldehyde dehydrogenase 2 polymorphisms on neuropsychological performance in bipolar II disorder with or without comorbid anxiety disorder

Anxiety disorders (ADs), the most common comorbid illnesses with bipolar disorder (BP) has been reported to associate with dopamine system. Dopamine, metabolized to 3,4-dihydroxyphenylacetic acid (DOPAC) by aldehyde dehydrogenase 2 (ALDH2), and the distribution of the ALDH2*1/*1, and ALDH2*1/*2+ALDH*2/*2 alleles in the Han Chinese general population is relatively equal. The association between dopamine metabolic enzymes and cognitive performance in patients with bipolar II disorder (BP-II) comorbid with AD is unclear. This study proposed to explore the role of ALDH2 polymorphisms on neuropsychological performance between BP-II comorbid with or without AD. One hundred ninety-seven BP-II patients with and without a comorbid AD were recruited and compared with 130 healthy controls (HCs). A polymerase chain reaction and a restriction fragment length polymorphism analysis were used to determine genotypes for ALDH2, and study participants underwent neuropsychological tests. An interaction between AD comorbidity and the ALDH2 polymorphisms was found in different domain of cognitive dysfunction in the BP-II patients. The ALDH2 polymorphisms might have different effects on the neuropsychological performance of BP-II patients with and without comorbid AD.

ALDH2 Glu504Lys Confers Susceptibility to Schizophrenia and Impacts Hippocampal-Prefrontal Functional Connectivity

Although previous evidence suggested that ALDH2 is a candidate gene for schizophrenia, the association and underlying mechanisms have never been investigated. Therefore, we investigated ALDH2 as a susceptibility gene for schizophrenia and explored the effect of its polymorphisms on brain functions. In the discovery stage, we detected a positive association between a dominant-negative mutant, Glu504Lys, and schizophrenia (P= 8.01E-5, OR = 1.34, 95% CI = 1.16-1.55). This association was confirmed in the validation stage (P= 3.48E-6, OR = 1.28, 95% CI = 1.15-1.42). The combined P reached a genome-wide significance (Pcombined= 1.32E-9, OR = 1.30, 95% CI = 1.20-1.42). To investigate the neural mechanism linking Glu504Lys to schizophrenia, we calculated the functional connectivity (FC) and applied an imaging genetics strategy using resting-state fMRI data. The imaging analysis revealed a significant interaction of diagnostic group by genotype for FC between the left hippocampus and the prefrontal cortex. In the Glu homozygotes, hippocampal-prefrontal FC correlated inversely with memory performance in the healthy controls and with the PANSS negative score in the schizophrenia patients. Our results supported a role for ALDH2 in the pathophysiology of schizophrenia. Moreover, variation at Glu504Lys disrupts hippocampal-prefrontal FC, which might be the neural mechanism linking it to the disease.

Mesocorticolimbic dopamine functioning in primary psychopathy: A source of within-group heterogeneity

Despite similar emotional deficiencies, primary psychopathic individuals can be situated on a continuum that spans from controlled to disinhibited. The constructs on which primary psychopaths are found to diverge, such as self-control, cognitive flexibility, and executive functioning, are crucially regulated by dopamine (DA). As such, the goal of this review is to examine which specific alterations in the meso-cortico-limbic DA system and corresponding genes (e.g., TH, DAT, COMT, DRD2, DRD4) might bias development towards a more controlled or disinhibited expression of primary psychopathy. Based on empirical data, it is argued that primary psychopathy is generally related to a higher tonic and population activity of striatal DA neurons and lower levels of D2-type DA receptors in meso-cortico-limbic projections, which may boost motivational drive towards incentive-laden goals, dampen punishment sensitivity, and increase future reward-expectancy. However, increasingly higher levels of DA activity in the striatum (moderate versus pathological elevations), lower levels of DA functionality in the prefrontal cortex, and higher D1-to-D2-type receptor ratios in meso-cortico-limbic projections may lead to increasingly disinhibited and impetuous phenotypes of primary psychopathy. Finally, in order to provide a more coherent view on etiological mechanisms, we discuss interactions between DA and serotonin that are relevant for primary psychopathy.

Interaction of DRD2TaqI, COMT, and ALDH2 genes associated with bipolar II disorder comorbid with anxiety disorders in Han Chinese in Taiwan

It is hypothesized that dopaminergic genes-dopamine type-2 receptor (DRD2), aldehyde dehydrogenase 2 (ALDH2), and catechol-O-methyltransferase (COMT)-are associated with bipolar disorder (BP) and anxiety disorder (AD). Bipolar II (BP-II) is reported to be highly comorbid with AD. We examined whether interactions among these three genes are susceptibility factors in BP-II with AD (BP-II(+AD)) and without AD (BP-II(-AD)). In this study, we hypothesize that the interaction of the dopaminergic genes between BP-II(+AD) and BP-II(-AD) is significant different. We recruited 1260 participants: 495 with BP-II(-AD), 170 with BP-II(+AD), and 595 healthy controls without BP-II or AD. Genotyping was done using polymerase chain reactions plus restriction fragment length polymorphism analysis. Genotypic frequencies of the DRD2TaqIA, COMT, and ALDH2 polymorphisms between the two BP-II groups were nonsignificant. In logistic regression, the ALDH2 and DRD2TaqIA genes showed a main effect that was protective against BP-II(-AD) (odds ratio [OR] = 0.497, p = 0.010, and OR = 0.415, p = 0.017, respectively). The interaction of DRD2TaqIA A1/A1 and ALDH2*1/*1 had a significant risk effect on the BP-II(-AD) group (OR = 7.177, p < 0.001). However, the interaction of DRD2TaqIA A1/A1, ALDH2*1/*1, and COMTMet/Met&Val/Met become a weak protective factor against BP-II(-AD) (OR = 0.205, p = 0.047). All of the significant results described above are found only in BP-II(-AD). This study supports the hypothesis the interaction of the dopaminergic genes between BP-II(+AD) and BP-II(-AD) is significant different,, and provides additional evidence that the DRD2TaqIA A1/A1, ALDH2*1/*1 and COMT genes interact in BP-II(-AD) but not in BP-II(+AD).

A personalized medicine approach for Asian Americans with the aldehyde dehydrogenase 2*2 variant

Asian Americans are one of the fastest-growing populations in the United States. A relatively large subset of this population carries a unique loss-of-function point mutation in aldehyde dehydrogenase 2 (ALDH2), ALDH2*2. Found in approximately 560 million people of East Asian descent, ALDH2*2 reduces enzymatic activity by approximately 60% to 80% in heterozygotes. Furthermore, this variant is associated with a higher risk for several diseases affecting many organ systems, including a particularly high incidence relative to the general population of esophageal cancer, myocardial infarction, and osteoporosis. In this review, we discuss the pathophysiology associated with the ALDH2*2 variant, describe why this variant needs to be considered when selecting drug treatments, and suggest a personalized medicine approach for Asian American carriers of this variant. We also discuss future clinical and translational perspectives regarding ALDH2*2 research.

The DRD2 rs1800497 polymorphism increase the risk of mood disorder: evidence from an update meta-analysis

BACKGROUND

Growing studies have revealed the association between rs1800497 polymorphism in the dopamine receptor D2 (DRD2) and susceptibility to mood disorder (MD). However, the results remained inconsistent.

METHODS

To assess the effect of DRD2 rs1800497 polymorphism on MD. We performed a meta-analysis based on eight case-control studies, including a total of 2097 MD cases and 1681 controls. Summary odds ratios (OR) and corresponding 95% confidence intervals (CIs) for DRD2 rs1800497 polymorphism and MD risk were estimated.

RESULTS

Our meta-analysis indicated that DRD2 rs1800497 was associated with an increased MD risk, especially in Asians. Moreover, in the subgroup analysis by the type of MD, DRD2 rs1800497 polymorphism was observed to increase risk in BP.

LIMITATIONS

The results should be treated with caution for lacking of data to perform gene-gene and gene-environment interaction.

CONCLUSIONS

Our results indicated that polymorphism in DRD2 rs1800497 may play a role in development of MD.