Val/Val genotype of brain-derived neurotrophic factor (BDNF) Val⁶⁶Met polymorphism is associated with a better response to OROS-MPH in Korean ADHD children

A Review of Biomarkers in Delirium Superimposed on Dementia (DSD) and Their Clinical Application to Personalized Treatment and Management

Delirium superimposed on dementia (DSD) occurs when patients with pre-existing dementia develop delirium. This complication causes patients to become impaired, posing safety concerns for both hospital staff and patients. Furthermore, there is an increased risk of worsening functional disability and death. Despite medical advances, DSD provides both diagnostic and therapeutic challenges to providers. Identifying at-risk patients and providing personalized medicine and patient care can decrease disease burden in a time-efficient manner. This review delves into bioinformatics-based studies of DSD in order to design and implement a personalized medicine-based approach. Our findings suggest alternative medical treatment methods based on gene-gene interactions, gene-microRNA (miRNA) interactions, gene-drug interactions, and pharmacogenetic variants involved in dementia and psychiatric disorders. We identify 17 genes commonly associated with both dementia and delirium including apolipoprotein E (ApoE), brain-derived neurotrophic factor (BDNF), catechol-O-methyltransferase (COMT), butyrylcholinesterase (BChE), acetylcholinesterase (AChE), DNA methyltransferase 1 (DNMT1), prion protein (PrP), tumor necrosis factor (TNF), serine palmitoyltransferase long chain base subunit 1 (SPTLC1), microtubule-associated protein tau (MAPT), alpha-synuclein (αS), superoxide dismutase 1 (SOD1), amyloid beta precursor protein (APP), neurofilament light (NFL), neurofilament heavy, 5-hydroxytryptamine receptor 2A (HTR2A), and serpin family A member 3 (ERAP3). In addition, we identify six main genes that form an inner concentric model, as well as their associated miRNA. The FDA-approved medications that were found to be effective against the six main genes were identified. Furthermore, the PharmGKB database was used to identify variants of these six genes in order to suggest future treatment options. We also looked at previous research and evidence on biomarkers that could be used to detect DSD. According to research, there are three types of biomarkers that can be used depending on the stage of delirium. The pathological mechanisms underlying delirium are also discussed. This review will identify treatment and diagnostic options for personalized DSD management.

Negative relationship between brain-derived neurotrophic factor (BDNF) and attention: A possible elevation in BDNF level among high-altitude migrants

Objective

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophic family that plays a vital role in regulating neuronal activity and synaptic plasticity in the brain, affects attention. However, studies investigating the association between BDNF and attention in long-term high-altitude (HA) migrants are limited in the literature. As HA affects both BDNF and attention, the relationship between these factors becomes more complex. Therefore, this study aimed to evaluate the relationship between peripheral blood concentrations of BDNF and the three attentional networks in both behavioral and electrical aspects of the brain in long-term HA migrants.

Materials and methods

Ninety-eight Han adults (mean age: 34.74 ± 3.48 years, 51 females and 47 males, all have lived at Lhasa for 11.30 ± 3.82 years) were recruited in this study. For all participants, the serum BDNF levels were assessed using enzyme-linked immunosorbent assay; event-related potentials (N1, P1, and P3) were recorded during the Attentional Networks Test, which was used as the measure of three attentional networks.

Results

Executive control scores were negatively correlated with P3 amplitude (r = -0.20, p = 0.044), and serum BDNF levels were positively correlated with executive control scores (r = 0.24, p = 0.019) and negatively correlated with P3 amplitude (r = -0.22, p = 0.027). Through grouping of BDNF levels and three attentional networks, executive control was found to be significantly higher in the high BDNF group than in the low BDNF group (p = 0.010). Different BDNF levels were associated with both orienting scores (χ² = 6.99, p = 0.030) and executive control scores (χ² = 9.03, p = 0.011). The higher the BDNF level, the worse was the executive function and the lower was the average P3 amplitude and vice versa. Females were found to have higher alerting scores than males (p = 0.023).

Conclusion

This study presented the relationship between BDNF and attention under HA. The higher the BDNF level, the worse was the executive control, suggesting that after long-term exposure to HA, hypoxia injury of the brain may occur in individuals with relatively higher BDNF levels, and this higher BDNF level may be the result of self-rehabilitation tackling the adverse effects brought by the HA environment.

Outcomes of a 12-week ecologically valid observational study of first treatment with methylphenidate in a representative clinical sample of drug naïve children with ADHD

Randomized placebo-controlled trials have reported efficacy of methylphenidate (MPH) for Attention-deficit/hyperactivity disorder (ADHD); however, selection biases due to strict entry criteria may limit the generalizability of the findings. Few ecologically valid studies have investigated effectiveness of MPH in representative clinical populations of children. This independently funded study aims to describe treatment responses and their predictors during the first 12 weeks of MPH treatment using repeated measurements of symptoms and adverse reactions (ARs) to treatment in 207 children recently diagnosed with ADHD. The children were consecutively included from the Child and Adolescent Mental Health Centre, Mental Health Services, The Capital Region of Denmark. The children (mean age, 9.6 years [range 7–12], 75.4% males) were titrated with MPH, based on weekly assessments of symptoms (18-item ADHD-rating scale scores, ADHD-RS-C) and ARs. At study-end 187 (90.8%) children reached a mean end-dose of 1.0 mg/kg/day. A normalisation/borderline normalisation on ADHD-RS-C was achieved for 168 (81.2%) children on the Inattention and/or the Hyperactivity-Impulsivity subscale in week 12, and 31 (15.0%) children were nonresponders, which was defined as absence of normalisation/borderline normalisation (n = 19) or discontinuation due to ARs (n = 12), and eight (3.8%) children dropped out from follow-up. Nonresponders were characterised by more severe symptoms of Hyperactivity-Impulsivity and global impairment before the treatment. ARs were few; the most prominent were appetite reduction and weight loss. A decrease in AR-like symptoms during the treatment period questions the validity of currently available standard instruments designed to measure ARs of MPH. This ecologically valid observational study supports prior randomized placebo-controlled trials; 81.2% of the children responded favourably in multiple domains with few harmful effects to carefully titrated MPH.

Clinical trial registration: ClinicalTrials.gov with registration number NCT04366609.

Genetic polymorphisms for BDNF, COMT, and APOE do not affect gait or ankle motor control in chronic stroke: A preliminary cross-sectional study

Background: Motor deficits after stroke are a primary cause of long-term disability. The extent of functional recovery may be influenced by genetic polymorphisms. Objectives: Determine the effect of genetic polymorphisms for brain-derived neurotrophic factor (BDNF), catechol-O-methyltransferase (COMT), and apolipoprotein E (APOE) on walking speed, walking symmetry, and ankle motor control in individuals with chronic stroke. Methods: 38 participants with chronic stroke were compared based upon genetic polymorphisms for BDNF (presence [MET group] or absence [VAL group] of a Met allele), COMT (presence [MET group] or absence [VAL group] of a Met allele), and APOE (presence [ε4+ group] of absence [ε4- group] of ε4 allele). Comfortable and maximal walking speed were measured with the 10-m walk test. Gait spatiotemporal symmetry was measured with the GAITRite electronic mat; symmetry ratios were calculated for step length, step time, swing time, and stance time. Ankle motor control was measured as the accuracy of performing an ankle tracking task. Results: No significant differences were detected (p ≥ 0.11) between the BDNF, COMT, or APOE groups for any variables. Conclusions: In these preliminary findings, genetic polymorphisms for BDNF, COMT, and APOE do not appear to affect walking speed, walking symmetry, or ankle motor performance in chronic stroke.

The BDNF Val66Met Polymorphism Moderates the Relationship Between Posttraumatic Stress Disorder and Trauma Script-evoked Attentional Bias to Cocaine Cues Among Patients with Cocaine Dependence

There is extensive variability in cocaine-related attentional bias (AB) following trauma script exposure among cocaine-dependent (CD) patients with posttraumatic stress disorder (PTSD). Therefore, research is needed to identify the specific PTSD-CD patients most likely to exhibit an AB to cocaine cues. A common polymorphism in brain-derived neurotrophic factor (BDNF), Val66met, is associated with risk for stimulant addiction, and thus, was examined as a moderator of the association between PTSD and cocaine-related AB following trauma script exposure in this study. Adult CD patients with (n = 17) and without (n = 28) PTSD were exposed to a personalized trauma script, followed by a visual dot-probe task assessing cocaine-related AB. Task response times were used to examine traditionally calculated AB scores, as well as trial level bias scores (TL-BS) that more accurately model the temporal dynamics of AB. PTSD-CD patients homozygous for the BDNF Val/Val genotype exhibited greater bias for attending to cocaine-related stimuli following trauma script exposure than those carrying the Met allele. The PTSD by BDNF interaction did not predict response time variability on trials for which only neutral stimuli were presented, thus increasing confidence that the observed effect is specific to cocaine-related stimuli. PTSD-CD patients homozygous for the BDNF Val/Val genotype may be at particularly high risk for negative clinical outcomes (e.g., relapse, treatment dropout) as a function of prolonged attentional engagement with cocaine cues when exposed to trauma reminders.

Genetic Influence on Efficacy of Pharmacotherapy for Pediatric Attention-Deficit/Hyperactivity Disorder: Overview and Current Status of Research

Multiple stimulant and non-stimulant medications are approved for the treatment of attention-deficit/hyperactivity disorder (ADHD), one of the most prevalent childhood neurodevelopmental disorders. Choosing among the available agents and determining the most effective ADHD medication for a given child can be a time-consuming process due to the high inter-individual variability in treatment efficacy. As a result, there is growing interest in identifying predictors of ADHD medication response in children through the burgeoning field of pharmacogenomics. This article reviews childhood ADHD pharmacogenomics efficacy studies published during the last decade (2009-2019), which have largely focused on pharmacodynamic candidate gene investigations of methylphenidate and atomoxetine response, with a smaller number investigating pharmacokinetic candidate genes and genome-wide approaches. Findings from studies which have advanced the field of ADHD pharmacogenomics through investigation of meta-analytic approaches and gene-gene interactions are also overviewed. Despite recent progress, no one genetic variant or currently available pharmacogenomics test has demonstrated clinical utility in pinpointing the optimal ADHD medication for a given individual patient, highlighting the need for further investigation.

Association between BDNF gene polymorphisms and attention deficit hyperactivity disorder in school-aged children in Wuhan, China

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is vital for neuronal survival and growth, regulation of synaptic plasticity, and cognitive function. Previous studies examined the role of BDNF in susceptibility to attention deficit hyperactivity disorder (ADHD). The current study examined the association between BDNF gene polymorphisms and ADHD in Chinese children.

METHODS

Participants were 195 medication-naive ADHD children and 263 unaffected healthy controls. ADHD symptoms were diagnosed using the Vanderbilt ADHD Diagnostic Parental Rating Scale according to the Diagnostic and Statistical Manual of Mental Disorders-5. Five BDNF single nucleotide polymorphisms were detected using improved multiplex ligation detection reaction. Alleles and genotype frequency were examined using Chi-square tests. Correlations were examined using multivariate logistic regression analysis in the ADHD and control groups.

RESULTS

The results revealed that rs12291186 with one or both mutated allele(s) was significantly associated with reduced likelihood of ADHD (OR = 0.13, 95% CI: 0.02-0.77) and ADHD-Combined (OR = 0.10, 95% CI: 0.01-0.85). Children with genotype AA or CA in rs10835210 exhibited increased risk of ADHD (OR = 3.29, 95% CI: 1.03-10.55) and ADHD-Combined (OR = 4.45, 95% CI: 1.10-17.96) compared with genotype CC children. No significant associations were found between rs6265, rs7103411, rs7103873 polymorphisms and ADHD.

LIMITATIONS

Participants were recruited from urban areas. We were unable to examine all potential confounding factors.

CONCLUSIONS

BDNF gene polymorphisms of rs12291186 and rs10835210 were related to the occurrence of ADHD. These findings provide new insight on mechanisms underlying BDNF gene in ADHD.

Pharmacogenetics predictors of methylphenidate efficacy in childhood ADHD

Stimulant medication has long been effective in treating attention-deficit/hyperactivity disorder (ADHD) and is currently the first-line pharmacological treatment for children. Both methylphenidate and amphetamine modulate extracellular catecholamine levels through interaction with dopaminergic, adrenergic and serotonergic system components; it is therefore likely that catecholaminergic molecular components influence the effects of ADHD treatment. Using meta-analysis, we sought to identify predictors of pharmacotherapy to further the clinical implementation of personalized medicine. We identified 36 studies (3647 children) linking the effectiveness of methylphenidate treatment with DNA variants. Pooled-data revealed a statistically significant association between single nucleotide polymorphisms (SNPs) rs1800544 ADRA2A (odds ratio: 1.69; confidence interval: 1.12-2.55), rs4680 COMT (odds ratio (OR): 1.40; confidence interval: 1.04-1.87), rs5569 SLC6A2 (odds ratio: 1.73; confidence interval: 1.26-2.37) and rs28386840 SLC6A2 (odds ratio: 2.93; confidence interval: 1.76-4.90), and, repeat variants variable number tandem repeat (VNTR) 4 DRD4 (odds ratio: 1.66; confidence interval: 1.16-2.37) and VNTR 10 SLC6A3 (odds ratio: 0.74; confidence interval: 0.60-0.90), whereas the following variants were not statistically significant: rs1947274 LPHN3 (odds ratio: 0.95; confidence interval: 0.71-1.26), rs5661665 LPHN3 (odds ratio: 1.07; confidence interval: 0.84-1.37) and VNTR 7 DRD4 (odds ratio: 0.68; confidence interval: 0.47-1.00). Funnel plot asymmetry among SLC6A3 studies was identified and attributed largely to small study effects. Egger's regression test and Duval and Tweedie's 'trim and fill' were used to examine and correct for publication bias. These findings have major implications for advancing our therapeutic approach to childhood ADHD treatment.

Differential Behavioral and Biochemical Responses to Caffeine in Male and Female Rats from a Validated Model of Attention Deficit and Hyperactivity Disorder

Epidemiological studies suggest sex differences in attention deficit and hyperactivity disorder (ADHD) symptomatology. The potential benefits of caffeine have been reported in the management of ADHD, but its effects were not properly addressed with respect to sex differences. The present study examined the effects of caffeine (0.3 g/L) administered since childhood in the behavior and brain-derived neurotrophic factor (BDNF) and its related proteins in both sexes of a rat model of ADHD (spontaneously hypertensive rats-SHR). Hyperlocomotion, recognition, and spatial memory disturbances were observed in adolescent SHR rats from both sexes. However, females showed lack of habituation and worsened spatial memory. Although caffeine was effective against recognition memory impairment in both sexes, spatial memory was recovered only in female SHR rats. Besides, female SHR rats showed exacerbated hyperlocomotion after caffeine treatment. SHR rats from both sexes presented increases in the BDNF, truncated and phospho-TrkB receptors and also phospho-CREB levels in the hippocampus. Caffeine normalized BDNF in males and truncated TrkB receptor at both sexes. These findings provide insight into the potential of caffeine against fully cognitive impairment displayed by females in the ADHD model. Besides, our data revealed that caffeine intake since childhood attenuated behavioral alterations in the ADHD model associated with changes in BDNF and TrkB receptors in the hippocampus.

Serum brain-derived neurotrophic factor levels in treatment-naïve boys with attention-deficit/hyperactivity disorder treated with methylphenidate: an 8-week, observational pretest-posttest study

Brain-derived neurotrophic factor (BDNF) is an important neurotrophin in the brain that modulates dopaminergic neurons. In this study, we aimed to investigate the changes in serum BDNF levels of children with attention-deficit/hyperactivity disorder (ADHD) in response to OROS methylphenidate treatment. We also aimed to determine whether there were any pre-post-differences between ADHD subtypes and comorbid psychiatric disorders in serum BDNF levels. Fifty male children with ADHD and 50 male healthy controls within the age range of 6-12 years were recruited to the study. The psychiatric diagnoses were determined by applying a structured interview with Kiddie schedule for affective disorders and schizophrenia for school-age children-present and lifetime version. The symptom severity of ADHD was measured using the Clinical Global Impression ADHD Severity Scale (CGI-S). Physicians completed Du Paul ADHD questionnaires. The levels of serum BDNF were assessed before and after 8 weeks of treatment with effective dosages of OROS methylphenidate. In the present study, the mean serum BDNF levels of boys with ADHD and of the healthy controls were 2626.33 ± 1528.05 and 2989.11 ± 1420.08 pg/mL, respectively. Although there were no statistically significant difference between the ADHD group and healthy controls at baseline (p = 0.22), the increase of serum BDNF was statistically significant from baseline to endpoint in the ADHD group (p = 0.04). The mean serum BDNF levels at baseline and endpoint of the ADHD group were 2626.33 ± 1528.05 and 3255.80 ± 1908.79 pg/mL, respectively. The serum BDNF levels of ADHD-inattentive subtype were significantly lower at baseline (p = 0.02), whereas BDNF levels post-treatment showed no significant difference. The increase of serum BDNF levels with methylphenidate treatment after 8 weeks was significantly higher in the inattentive group (p = 0.005). The increase of serum BDNF levels with methylphenidate treatment after 8 weeks in boys with ADHD may support the potential role of BDNF in the pathophysiology of ADHD. The role of BDNF in ADHD subtypes in particular should be evaluated with further, larger studies.

A candidate gene investigation of methylphenidate response in adult attention-deficit/hyperactivity disorder patients: results from a naturalistic study

Attention-deficit/hyperactivity disorder (ADHD) is a common childhood onset neuropsychiatric disorder with a complex and heterogeneous symptomatology. Persistence of ADHD symptoms into adulthood is common. Methylphenidate (MPH) is a widely prescribed stimulant compound that may be effective against ADHD symptoms in children and adults. However, MPH does not exert satisfactory effect in all patients. Several genetic variants have been proposed to predict either treatment response or adverse effects of stimulants. We conducted a literature search to identify previously reported variants associated with MPH response and additional variants that were biologically plausible candidates for MPH response. The response to MPH was assessed by the treating clinicians in 564 adult ADHD patients and 20 genetic variants were successfully genotyped. Logistic regression was used to test for association between these polymorphisms and treatment response. Nominal associations (p < 0.05) were meta-analysed with published data from previous comparable studies. In our analyses, rs1800544 in the ADRA2A gene was associated with MPH response at a nominal significance level (OR 0.560, 95 % CI 0.329–0.953, p = 0.033). However, this finding was not affirmed in the meta-analysis. No genetic variants revealed significant associations after correction for multiple testing (p < 0.00125). Our results suggest that none of the studied variants are strong predictors of MPH response in adult ADHD as judged by clinician ratings, potentially except for rs1800544. Consequently, pharmacogenetic testing in routine clinical care is not supported by our analyses. Further studies on the pharmacogenetics of adult ADHD are warranted.

The role of the brain-derived neurotrophic factor genotype and parenting in early life in predicting externalizing and internalizing symptoms in children with attention-deficit hyperactivity disorder

BACKGROUND

We aimed to determine whether early parenting is associated with externalizing and internalizing symptoms in children with attention-deficit hyperactivity disorder (ADHD) and whether such an association is affected by the brain-derived neurotrophic factor (BDNF) val66met polymorphism.

METHODS

The participants included 92 patients with ADHD aged 6-15 years. Measures of parenting in early life and externalizing and internalizing symptoms and the genotype of the BDNF Val66Met polymorphism were obtained.

RESULTS

The degree to which the baby's autonomy was allowed was significantly and negatively correlated with the CDI scores in ADHD children (r = -0.38, p = 0.005). After adjusting for the child's gender, the child's age, the family's gross annual income, and the maternal education level, there was a significant interaction for the BDNF genotype and mother's positive feelings about caring in relation to the development of childhood anxiety/depression in ADHD children (F = 2.51, p = 0.011).

CONCLUSIONS

Our results provide evidence of an interaction between the BDNF met allele and early parenting on the development of depression/anxiety symptoms.

The Physiology of BDNF and Its Relationship with ADHD

Brain-derived neurotrophic factor (BDNF) is a major neurotrophin in the central nervous system that plays a critical role in the physiological brain functions via its two independent receptors: tropomyosin-related kinase B (TrkB) and p75, especially in the neurodevelopment. Disrupting of BDNF and its downstream signals has been found in many neuropsychological diseases, including attention-deficit hyperactivity disorder (ADHD), a common mental disorder which is prevalent in childhood. Understanding the physiological functions of BDNF during neural development and its potential relationship with ADHD will help us to elucidate the possible mechanisms of ADHD and to develop therapeutic approaches for this disease. In this review, we summarized the important literatures for the physiological functions of BDNF in the neurodevelopment. We also performed an association study on the functional genetic variation of BDNF and ADHD by a case-control study in the Chinese mainland population and revealed the potential correlation between BDNF and ADHD which needs further research to confirm.

ADHD pharmacogenetics across the life cycle: New findings and perspectives

Attention-deficit/hyperactivity disorder (ADHD) is a complex and heterogeneous disorder, affecting individuals across the life cycle. Although its etiology is not yet completely understood, genetics plays a substantial role. Pharmacological treatment is considered effective and safe for children and adults, but there is considerable inter-individual variability among patients regarding response to medication, required doses, and adverse events. We present here a systematic review of the literature on ADHD pharmacogenetics to provide a critical discussion of the existent findings, new approaches, limitations, and recommendations for future research. Our main findings are: first, the number of studies continues to grow, making ADHD one of the mental health areas with more pharmacogenetic studies. Second, there has been a focus shift on ADHD pharmacogenetic studies in the last years. There is an increasing number of studies assessing gene-gene and gene-environment interactions, using genome-wide association approaches, neuroimaging, and assessing pharmacokinetic properties. Third and most importantly, the heterogeneity in methodological strategies employed by different studies remains impressive. The question whether pharmacogenetics studies of ADHD will improve clinical management by shifting from trial-and-error approach to a pharmacological regimen that takes into account the individual variability remains unanswered. © 2014 Wiley Periodicals, Inc.

Changes in plasma Brain-derived neurotrophic factor (BDNF) levels induced by methylphenidate in children with Attention deficit-hyperactivity disorder (ADHD)

OBJECTIVES

It has been suggested that BDNF may play a role in the pathogenesis of ADHD. Our aim is to determine whether methylphenidate can induce changes in plasma BDNF levels of children with ADHD.

METHODS

We assessed levels of plasma BDNF in 28 ADHD patients (age range = 3.5-10 years) before and after 6 weeks treatment with effective dosages of methylphenidate. Then we evaluated the correlation of levels of plasma BDNF with clinical variables, especially ADHD Conner's parents rating scale.

RESULTS

According to the paired sample T-test, the mean plasma BDNF level in the baseline was 193.06 pg/ml, whereas 271.06 pg/ml in the end point, thus showing significantly higher mean plasma BDNF levels in the post-treatment situation than in the pretreatment (t = -3.393, df = 27, p = 0.002). Pearson's correlation test revealed that there was also significant negative correlation between levels of BDNF in the plasma of ADHD patients before treatment and improvement in hyperactivity symptoms with treatment (Pearson's correlation = -0.395, p = 0.037).

CONCLUSION

The mean plasma BDNF levels increased after 6 weeks of treatment with methylphenidate. Also, we found an improvement in hyperactivity symptoms with decreasing baseline plasma BDNF levels. We recommend that more studies should be conducted in order to assess the possible roles of plasma BDNF levels in treatment response prediction and prognosis.