Role of Glutamate Receptor-related Biomarkers in the Etiopathogenesis of ADHD

Objective

: Pathways associated with glutamate receptors are known to play a role in the pathophysiology of attention-deficit hyperactivity disorder (ADHD). However, cyclin-dependent kinase 5 (CDK5), microtubule-associated protein-2 (MAP2), guanylate kinase-associated protein (GKAP), and postsynaptic density 95 (PSD95), all of which are biomarkers involved in neurodevelopmental processes closely related to glutamatergic pathways, have not previously been studied in patients with ADHD. The main purpose of this study was to evaluate the plasma levels of CDK5, MAP2, GKAP, and PSD95 in children with ADHD and investigate whether these markers have a role in the etiology of ADHD.

Methods

: Ninety-six children with ADHD between 6 and 15 years of age and 72 healthy controls were included in the study. Five milliliters of blood samples were taken from all participants. The samples were stored at -80°C until analyzed by the enzyme-linked immunosorbent assay method.

Results

: Statistically significantly lower CDK5 levels were observed in children with ADHD than in healthy controls (p = 0.037). The MAP2, GKAP, and PSD95 levels were found to be statistically significantly higher in the ADHD group than in healthy controls (p = 0.012, p = 0.009, and p = 0.024, respectively). According to binary regression analysis, CDK5 and MAP2 levels were found to be predictors of ADHD.

Conclusion

: In conclusion, we found that a close relationship existed between ADHD and glutamatergic pathways, and low levels of CDK5 and high levels of MAP2 and GKAP played a role in the etiopathogenesis of ADHD.

S100B and Neuron-Specific Enolase Levels as Brain Injury Biomarkers in Internet Addiction: Effect of Sleep

BACKGROUND

Comorbidity of Internet addiction (IA) with sleep disruptions is common in adolescents. There is evidence that the levels of brain injury markers could be affected by sleep disruptions. In this study, we aimed to evaluate the relationship between sleep quality and these biomarkers within the framework of the relationship between IA and sleep disruptions.

METHODS

A total of 65 drug-free adolescents with newly diagnosed IA, aged 12 to 18 years, were included in the study, and they were divided into two groups considering the comorbidities of attention-deficit/hyperactivity disorder (ADHD) and social anxiety. The control group consisted of 30 healthy children. The participants were asked to complete the Young Internet Addiction Scale, Pittsburgh Sleep Quality Index (PSQI), Morningness Eveningness Questionnaire, Beck's Depression Inventory, Beck's Anxiety Inventory, and Barratt Impulsiveness Scale-11. Blood samples were taken between 8 and 9 am to analyze S100 calcium-binding protein B (S100B) and neuron-specific enolase (NSE) levels with enzyme-linked immunosorbent assay.

RESULTS

Plasma S100B and NSE levels were found to be statistically significantly higher in the IA with ADHD and the IA with anxiety groups than in healthy controls. NSE and S100B levels were found to be correlated with PSQI scores in both the IA groups. Also, there was a positive correlation between these biomarkers and IA severity.

CONCLUSIONS

Decreased sleep quality and daily sleep duration in IA might cause brain injury, resulting in an increase in the severity of the addiction. Prospective studies with large samples are needed to better explain the IA-sleep-brain injury relationship.

Nerve growth factor and angiotensin converting enzyme 2 levels in children with neurodevelopmental disorders

OBJECTIVE

Neurodevelopmental disorders (NDDs) are the most common psychiatric disorders in childhood, and there are many factors in their etiology. In recent years, many biomarkers have been studied to elucidate the etiology of these disorders. In this study, it was aimed to investigate the levels of nerve growth factor (NGF) and angiotensin converting enzyme 2 (ACE2) in attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and intellectual disability (ID).

METHODS

The study included 74 children with NDDs (the number of patients in ADHD, ASD and ID groups were 24, 25 and 25 respectively) and 30 healthy controls (HCs). Serum NGF and ACE2 levels were studied with ELISA kits, also complete blood count (CBC), levels of fasting glucose and serum lipids were assessed.

RESULTS

ACE2 levels were found to be lower in NDD group than HCs in girls. In boys with ASD, triglyceride levels were significantly higher than other groups. Also a positive correlation was found between ACE2 and NGF levels when all sample assessed together.

CONCLUSIONS

This study is a premise for investigating ACE2 and NGF in NDDs. The role of these markers in ADHD, ASD, ID and other NDDs and their associations with gender should be assessed by studies in which both larger sample groups and more disorders.

Role of the norepinephrine transporter polymorphisms in atomoxetine treatment: From response to side effects in children with ADHD

OBJECTIVE

Atomoxetine (ATX), one of the most commonly used drugs after stimulants in attention deficit hyperactivity disorder (ADHD) treatment, is an inhibitor of the norepinephrine transporter (NET/SLC6A2), which is also associated with the etiology of ADHD. In this study, we aimed to investigate the effect of NET gene polymorphisms on response to ATX treatment and to find the answers to the questions about whether there is a relationship between the severity of the disorder and the observed side effects in children with ADHD.

METHOD

About 100 children with ADHD and 80 healthy controls (HCs) were included in this study. The dose of ATX was started at 0.5 mg/kg/day and titrated at 1.2 mg/kg/day. Response to treatment of 78 patients was evaluated 2 months after the beginning of the treatment. After whole blood samples were obtained, DNAs were isolated, and samples were stored at -80°C. Two single-nucleotide polymorphisms (SNPs) (rs12708954 and rs3785143) were analyzed by real-time quantitative PCR (qRT-PCR).

RESULTS

The patients with both rs12708954 and rs3785143 heterozygous genotype had better treatment response and more side effects than patients with wild type. There was not found any association between any of the investigated NET polymorphisms and ADHD severity.

CONCLUSION

It was, however, found that the NET rs12708954 and rs3785143 genotypes affect the treatment response to ATX in our study; thus, further studies with a large population are needed to understand the effects of NET polymorphisms on treatment, side effects, and also the severity of ADHD.

Identification of molecular markers associated with fruit traits in olive and assessment of olive core collection with AFLP markers and fruit traits

The purpose of this study was to characterize olive core collection with amplified fragment length polymorphism (AFLP) markers and fruit traits and to determine AFLP markers significantly associated with these fruit characters in olive. A total of 168 polymorphic AFLP markers generated by five primer combinations and nine fruit traits were used to characterize relationships between 18 olive cultivars. Although all olive cultivars were discriminated from each other by either AFLP markers (<0.75 similarity level) or fruit traits, clustering based on the AFLP markers and fruit traits was not significantly correlated (r = 0.13). Partial clustering of olive cultivars by AFLP markers according to their geographical origin was observed. Associations of AFLP markers with fruits were determined using a multiple-regression analysis with stepwise addition of AFLP markers. Significant associations between eight AFLP markers and fruit traits were identified. While five AFLP markers demonstrated significant negative correlation with fruit and stone weight, width and length and total polyphenols (P < 0.05), three AFLP markers displayed significant positive correlation with α-tocopherol and γ-tocopherol (P < 0.01). This is the first report on the association of molecular markers with fruit traits in olive. Molecular markers associated with morphological and agronomic traits could be utilized for the breeding of olive cultivars. However, the association power of these markers needs to be confirmed in larger populations, and highly correlated markers should then be converted to PCR-based DNA markers such as sequence-characterized amplified region markers for better utilization.

Association of SSR markers with contents of fatty acids in olive oil and genetic diversity analysis of an olive core collection

The purpose of this research was to characterize an olive core collection using some agronomic characters and simple sequence repeat (SSR) markers and to determine SSR markers associated with the content of fatty acids in olive oil. SSR marker analysis demonstrated the presence of a high amount of genetic variation between the olive cultivars analyzed. A UPGMA dendrogram demonstrated that olive cultivars did not cluster on the basis of their geographic origin. Fatty acid components of olive oil in these cultivars were determined. The results also showed that there was a great amount of variation between the olive cultivars in terms of fatty acid composition. For example, oleic acid content ranged from 57.76 to 76.9% with standard deviation of 5.10%. Significant correlations between fatty acids of olive oil were observed. For instance, a very high negative correlation (-0.812) between oleic and linoleic acids was detected. A structured association analysis between the content of fatty acids in olive oil and SSR markers was performed. STRUCTURE analysis assigned olive cultivars to two gene pools (K = 2). Assignment of olive cultivars to these gene pools was not based on geographical origin. Association between fatty acid traits and SSR markers was evaluated using the general linear model of TASSEL. Significant associations were determined between five SSR markers and stearic, oleic, linoleic, and linolenic acids of olive oil. Very high associations (P < 0.001) between ssrOeUA-DCA14 and stearic acid and between GAPU71B and oleic acid indicated that these markers could be used for marker-assisted selection in olive.