The Impact of Systemic Inflammation on Neurodevelopment

Inflammatory mediators affect the brain during development. Neurodevelopmental disorders such as autism spectrum disorders, cognitive impairment, cerebral palsy, epilepsy, and schizophrenia have been linked to early life inflammation. Recent advances have shown the effects of systemic inflammation on children's neurodevelopment. We discuss the potential mechanisms by which inflammatory molecules can exert their effects on the developing brain and consider the roles of MHC class I molecules, the HPA axis, glial cells, and monoamine metabolism. Methods to prevent the effects of cytokine imbalance may lead to the development of new therapeutics for neuropsychiatric disorders. Future research should focus on identifying at-risk individuals and early effective interventions to prevent long-term neurodevelopmental disabilities.

Induction of the UDP-Glucuronosyltransferase 1A1 during the Perinatal Period Can Cause Neurodevelopmental Toxicity

Anticonvulsants can increase the risk of developing neurotoxicity in infants; however, the underlying mechanism has not been elucidated to date. Thyroxine [3,5,3',5'-l-tetraiodothyronine (T4)] plays crucial roles in the development of the central nervous system. In this study, we hypothesized that induction of UDP-glucuronosyltransferase 1A1 (UGT1A1)-an enzyme involved in the metabolism of T4-by anticonvulsants would reduce serum T4 levels and cause neurodevelopmental toxicity. Exposure of mice to phenytoin during both the prenatal and postnatal periods significantly induced UGT1A1 and decreased serum T4 levels on postnatal day 14. In the phenytoin-treated mice, the mRNA levels of synaptophysin and synapsin I in the hippocampus were lower than those in the control mice. The thickness of the external granule cell layer was greater in phenytoin-treated mice, indicating that induction of UGT1A1 during the perinatal period caused neurodevelopmental disorders. Exposure to phenytoin during only the postnatal period also caused these neurodevelopmental disorders. A T4 replacement attenuated the increase in thickness of the external granule cell layer, indicating that the reduced T4 was specifically associated with the phenytoin-induced neurodevelopmental disorder. In addition, these neurodevelopmental disorders were also found in the carbamazepine- and pregnenolone-16-α-carbonitrile-treated mice. Our study is the first to indicate that UGT1A1 can control neurodevelopment by regulating serum T4 levels.

Long-Term Neurobehavioral and Quality of Life Outcomes of Critically Ill Children after Glycemic Control

OBJECTIVES

To investigate adaptive skills, behavior, and quality health-related quality of life in children from 32 centers enrolling in the Heart And Lung Failure-Pediatric INsulin Titration randomized controlled trial.

STUDY DESIGN

This prospective longitudinal cohort study compared the effect of 2 tight glycemic control ranges (lower target, 80-100 mg/dL vs higher target, 150-180 mg/dL) 1-year neurobehavioral and health-related quality of life outcomes. Subjects had confirmed hyperglycemia and cardiac and/or respiratory failure. Patients aged 2-16 years old enrolled between April 2012 and September 2016 were studied at 1 year after intensive care discharge. The primary outcome, adaptive skills, was assessed using the Vineland Adaptive Behavior Scale. Behavior and health-related quality of life outcomes were assessed as secondary outcomes using the Pediatric Quality of Life and Child Behavior Checklist at baseline and 1-year follow-up. Group differences were evaluated using regression models adjusting for age category, baseline overall performance, and risk of mortality.

RESULTS

Of 369 eligible children, 358 survived after hospital discharge and 214 (60%) completed follow-up. One-year Vineland Adaptive Behavior Scale-II composite scores were not different (mean ± SD, 79.9 ± 25.5 vs 79.4 ± 26.9, lower vs higher target; P = .20). Improvement in Pediatric Quality of Life total health from baseline was greater in the higher target group (adjusted mean difference, 8.2; 95% CI, 1.1-15.3; P = .02).

CONCLUSIONS

One-year adaptive behavior in critically ill children with lower vs higher target glycemic control did not differ. The higher target group demonstrated improvement from baseline in overall health. This study affirms the lack of benefit of lower glucose targeting.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01565941.

Biochemical phenotype and its relationship to treatment in 16 individuals with PCCB c.1606A > G (p.Asn536Asp) variant propionic acidemia

Propionic acidemia (PA) is caused by inherited deficiency of mitochondrial propionyl-CoA carboxylase (PCC) and results in significant neurodevelopmental and cardiac morbidity. However, relationships among therapeutic intervention, biochemical markers, and disease progression are poorly understood. Sixteen individuals homozygous for PCCB c.1606A > G (p.Asn536Asp) variant PA participated in a two-week suspension of therapy. Standard metabolic markers (plasma amino acids, blood spot methylcitrate, plasma/urine acylcarnitines, urine organic acids) were obtained before and after stopping treatment. These same markers were obtained in sixteen unaffected siblings. Echocardiography and electrocardiography were obtained from all subjects. We characterized the baseline biochemical phenotype of untreated PCCB c.1606A > G homozygotes and impact of treatment on PCC deficiency biomarkers. Therapeutic regimens varied widely. Suspension of therapy did not significantly alter branched chain amino acid levels, their alpha-ketoacid derivatives, or urine ketones. Carnitine supplementation significantly increased urine propionylcarnitine and its ratio to total carnitine. Methylcitrate blood spot and urine levels did not correlate with other biochemical measures or cardiac outcomes. Treatment of PCCB c.1606A > G homozygotes with protein restriction, prescription formula, and/or various dietary supplements has a limited effect on core biomarkers of PCC deficiency. These patients require further longitudinal study with standardized approaches to better understand the relationship between biomarkers and disease burden.

Exploring immunological and molecular mechanisms involved in obsessive-compulsive disorder with comorbid neurodevelopmental disorders

INTRODUCTION

Obsessive-compulsive disorder (OCD) is a psychiatric disease with a prevalence of 2%-3%. Despite the effectiveness of antidepressants, such as serotonin reuptake inhibitors, for treating OCD, its pathogenesis remains unclear. Recent research has implicated immunological mechanisms, particularly in OCD patients with comorbid neurodevelopmental disorders (NDD), such as autism spectrum disorder, attention deficit/hyperactive disorder, and Tourette's disorder. To examine these mechanisms, we investigated immunological factors involved in OCD patients with any NDD comorbidity (OCD + NDD group), compared with those without comorbid NDD (OCD group).

MATERIALS AND METHODS

Twenty-eight OCD patients treated at Hyogo Medical University Hospital were recruited for this study. Of them, 14 patients with NDD comorbidity (OCD + NDD) were compared with 14 patients without comorbid NDD (OCD). RNA was extracted from blood samples and analyzed using RNA sequencing and Ingenuity Pathway Analysis (IPA). Plasma levels of IL11 and IL17A were measured with ELISA.

RESULTS

RNA sequencing identified 716 significantly differentially expressed genes, with 47 related to immune functions, in the OCD + NDD group compared with the OCD group. IL11 and IL17A were central, with IL11 linked to neutrophil production and IL17A to T cell migration and cytokine secretion. Pathway analysis indicated complex interactions among these genes.

DISCUSSION

This study highlights significant immunological changes in OCD patients with any NDD. Decreased anti-inflammatory IL11 and increased proinflammatory IL17A suggest a shift towards inflammation, which may contribute to neurodevelopmental issues.

CONCLUSION

Immunological dysregulation in OCD with comorbid NDD may offer potential therapeutic targets. Immune gene interactions should be further investigated in effort to improve treatment strategies for treatment-refractory OCD patients, especially those with neurodevelopmental comorbidities.

Neonatal Circulating Amino Acids and Lipid Metabolites Mediate the Association of Maternal Gestational Diabetes Mellitus with Offspring Neurodevelopment at 1 Year

Background/Objectives: We aimed to identify neonatal circulating metabolic alterations associated with maternal gestational diabetes mellitus (GDM) and to explore whether these altered metabolites could mediate the association of GDM with offspring neurodevelopment. Additionally, we investigated whether neonatal circulating metabolites could improve the prediction of offspring neurodevelopmental disorders over traditional risk factors. Methods: The retrospective cohort study enrolled 1228 mother-child dyads in South China. GDM was diagnosed at 24-28 weeks of gestation. Neonatal circulating amino acids and lipid metabolites (carnitines) were measured from newborn heel blood 3-7 days postpartum. Offspring neurodevelopment was assessed at age 1 year using the Children Neuropsychological and Behavioral Examination Scale. Neurodevelopmental disorders were defined as developmental delay in any domain of the scale. Results: Twenty-one metabolites associated with GDM were identified, consisting of seven amino acids and fourteen carnitines. Among these metabolites, five (glycine, myristicylcarnitine, palmitoylcarnitine, octadecadienoylcarnitine, and 3-hydroxypalmitylcarnitine) mediated the negative association of GDM with offspring neurodevelopment at 1 year (mediation proportions: 3.91-10.66%). Furthermore, six metabolites (glycine, methionine, malonylcarnitine, isovalerylcarnitine, palmitoylcarnitine, and octadecadienoylcarnitine) significantly increased the predictive performance for offspring neurodevelopmental disorders at 1 year over five traditional risk factors including GDM, parity, infant sex, birth weight, and feeding patterns (area under curve: 0.762 vs. 0.718, p = 0.012). Conclusions: GDM was associated with a variety of amino acid and lipid metabolic alterations in neonatal circulation, among which certain metabolites mediated the association of GDM with adverse neurodevelopmental outcomes in offspring. Moreover, some neonatal circulating metabolites may serve as potential biomarkers that improved the prediction of offspring neurodevelopmental disorders over GDM and other traditional risk factors.

Predictive value of serum interleukin-6 for neonatal encephalopathy outcomes

Background: Serum interleukin-6 (IL-6) may predict adverse outcomes of neonatal encephalopathy (NE); however, limited data regarding the predictive utility of IL-6 during neurodevelopmental follow-up are available. We aimed to determine the utility of IL-6 for predicting adverse outcomes at 18 to 22 months of age.Methods: Eighty-seven patients with NE who received therapeutic hypothermia were enrolled in this study. Serial serum IL-6 levels during the first 3 postnatal days were collected. Patients were classified into three groups: (1) death, (2) survival with moderate to severe neurodevelopmental disability (NDD) at 18-22 months of age, and (3) survival without NDD (favorable outcome). The predictive ability of IL-6 was determined by the area under the receiver-operating characteristic curve (AUC).Results: Serial IL-6 data of 80 patients with NE were available and showed peak levels on postnatal day 1; these levels gradually decreased toward day 3. By 18-22 months of age, 13 and 17 patients died and experienced moderate to severe NDD without death, respectively. Fifty patients experienced favorable outcomes. Higher IL-6 levels on day 1 predicted the composite adverse outcome (including death and survival with NDD; n = 30; AUC, 0.648). Higher IL-6 levels on day 1 predicted death (n = 13; AUC, 0.799), whereas higher IL-6 levels on day 1 predicted survival with NDD (n = 17; AUC, 0.536).Conclusions: The AUC of IL-6 that predicted survival with NDD was lower than the AUC of IL-6 that predicted death; therefore, IL-6 may have insufficient utility for predicting NDD without death.

Valproic acid levels in neurodevelopmental disorders: correlation with CYP and SULT genes using LC-MS/MS

BACKGROUND

Valproic acid (VPA) is one of the most widely prescribed antiepileptic drugs worldwide, which is used to treat migraines, bipolar disorder, and anxiety. However, VPA is associated with a wide range of side effects. This study evaluates therapeutic drug monitoring (TDM) in individuals with neurodevelopmental disorders. It explores the correlation between valproic acid (VPA) plasma levels and genetic polymorphisms in cytochrome P450 (CYP) enzymes and cytosolic sulfotransferase (SULT) genes.

METHODS

A simple and accurate LC-MS/MS method was developed, validated, and applied in the TDM of 14 individuals on VPA therapy. Plasma VPA levels were measured, and genotyped genes SULT1A1, CYP2D64, CYP2D610, CYP3A5, and CYP2C19*2. Statistical analyses were conducted using SPSS.

RESULTS

Of the fourteen participants, two had toxic plasma VPA levels (≥ 100 µg/mL), one had a sub-therapeutic level (< 50 µg/mL), and eleven were within or slightly above the therapeutic range (50-100 µg/mL). No significant correlation was observed between VPA plasma concentrations and genotypes of SULT1A1 (p = 0.522), CYP2C192 (p = 0.288), CYP2D64 (p = 0.895), or CYP2D6*10 (p = 0.067). While no direct associations were found, genotype-guided drug therapy remains a promising strategy for optimizing drug efficacy and minimizing toxicity.

CONCLUSIONS

This study highlights the complexity of valproic acid (VPA) therapy in individuals with neurodevelopmental disorders and the limited influence of common genetic polymorphisms in CYP and SULT genes on VPA plasma levels. While therapeutic drug monitoring (TDM) remains an invaluable tool for optimizing VPA therapy, the lack of significant correlations between genetic variants and VPA concentrations suggests that routine pharmacogenetic testing for these specific variants may not be warranted in clinical practice. However, the observed toxic and sub-therapeutic VPA levels emphasize the importance of regular TDM to mitigate risks associated with overdose or insufficient dosing.

Convergent evidence linking neonatal vitamin D status and risk of neurodevelopmental disorders: a Danish case-cohort study

BACKGROUND

There is growing evidence linking neonatal vitamin D deficiency to an increased risk of schizophrenia, ADHD, and autism spectrum disorder (ASD). The aim of this study was to examine the association between two vitamin D biomarkers (25 hydroxyvitamin D [25(OH)D] and vitamin D-binding protein [DBP], and their related genetic correlates) and the risk of six mental disorders.

METHODS

We used a population-based, case-cohort sample of all individuals born in Denmark between 1981 and 2005. Using Danish health registers with follow-up to Dec 31, 2012, we identified individuals diagnosed with major depressive disorder, bipolar disorder, schizophrenia, ADHD, ASD, and anorexia nervosa based on ICD-10 criteria. Additionally, a random subcohort from the general population was selected. Based on neonatal dried blood spots, we measured concentrations of 25(OH)D and DBP. Our primary analyses were based on hazard ratios (HR) with 95% CI and absolute risks for the six mental disorders according to measured concentrations of 25(OH)D and DBP. As secondary analyses, we examined the association between genetic predictors of 25(OH)D and DBP, and the six mental disorders, and Mendelian randomisation analyses based on published summary statistics for 25(OH)D, DBP, and the six mental disorders. People with lived experience contributed to the development of the guiding hypothesis.

FINDINGS

We used the total population from the iPSYCH2012 design (n=88 764), which included individuals who developed the six mental disorders, major depressive disorder (n=24 240), bipolar disorder (n=1928), schizophrenia (n=3540), ADHD (n=18 726), ASD (n=16 146), anorexia nervosa (n=3643), and the randomly sampled subcohort (n=30 000). Among those who met a range of inclusion criteria (eg, measured 25[OH]D, DBP or genotype, and predominantly European ancestry), we measured 25(OH)D or DBP in 71 793 individuals (38 118 [53·1%] male and 33 675 [46·9%] female); 65 952 had 25(OH)D and 66 797 the DBP measurements. Significant inverse relationships were found between 25(OH)D and schizophrenia (HR 0·82, 95% CI 0·78-0·86), ASD (HR 0·93, 95% CI 0·90-0·96), and ADHD (HR 0·89, 95% CI 0·86-0·92). A significant inverse relationship was found between DBP and schizophrenia (HR 0·84, 95% CI 0·80-0·88). Based on polygenic risk scores, higher concentrations of 25(OH)D (adjusted for DBP) were significantly associated with a reduced risk of both ASD and schizophrenia. Analyses based on Mendelian randomisation provided support for a causal association between both lower 25(OH)D and DBP concentrations and an increased risk of ADHD.

INTERPRETATION

Convergent evidence finds that neonatal vitamin D status is associated with an altered risk of mental disorders. Our study supports the hypothesis that optimising neonatal vitamin D status might reduce the incidence of a range of neurodevelopmental disorders.

FUNDING

The Danish National Research Foundation.

Maternal Inflammatory Proteins in Pregnancy and Neurodevelopmental Disorders at Age 10 Years

IMPORTANCE

Maternal inflammation during pregnancy has been associated with an increased risk of neurodevelopmental disorders (NDDs), such as attention-deficit/hyperactivity disorder (ADHD) and autism, and cognitive deficits in early childhood. However, little is known about the contributions of a wider range of inflammatory proteins to this risk.

OBJECTIVE

To determine whether maternal inflammatory proteins during pregnancy are associated with the risk of NDDs and executive functions (EF) in middle childhood and to identify protein patterns associated with NDDs and EF.

DESIGN, SETTING, AND PARTICIPANTS

This was a 10-year follow-up cohort study of the Danish Copenhagen Prospective Studies on Asthma 2010 mother-child birth cohort, using plasma samples collected at week 24 in pregnancy, where 92 inflammatory proteins were assessed. NDDs and EF were assessed in the offspring at age 10 years, between January 2019 and December 2021. Mother-offspring dyads with available maternal prenatal inflammatory proteins during pregnancy and offspring NDD psychopathology data at follow-up were included. Data analyses took place between December 2023 and August 2024.

EXPOSURES

Levels of 92 inflammatory proteins from panel collected at week 24 during pregnancy.

MAIN OUTCOMES AND MEASURES

Categorical and dimensional psychopathology of NDDs (primary outcome) and EF (secondary outcome).

RESULTS

A total of 555 mothers (mean [SD] age, 32.4 [4.3] years) and their children (285 male [51%]) were included. The principal component analysis showed that higher levels of maternal inflammatory proteins depicted in principal component 1 were associated with a higher risk of any NDD (OR, 1.49; 95% CI, 1.15-1.94; P = .003), particularly autism (OR, 2.76; 95% CI, 1.45-5.63; P = .003) and ADHD with predominantly inattentive presentation (OR, 1.57; 95% CI, 1.05-2.39; P = .03). The single protein analysis showed that 18 of 92 proteins reached false discovery rate (FDR) 5% significance after adjustment. Vascular endothelial growth factor A, C-C motif chemokine ligand, CD5, interleukin 12B, fibroblast growth factor-23, and monocyte chemoattractant protein-1 emerged as top proteins associated with risk of NDDs. The sparse partial least squares approach identified 34 proteins associated with any NDD, and 39 with ADHD with predominantly inattentive presentation. There were no associations with EF after FDR correction.

CONCLUSIONS AND RELEVANCE

The maternal inflammatory proteome during pregnancy was associated with NDDs risks in offspring at age 10 years. Further research is warranted to elucidate the specific pathways involving these proteins during pregnancy that could be targeted with prevention strategies to reduce risk of NDDs in children.

Identification of immune cells and circulating inflammatory factors associated with neurodevelopmental disorders by bidirectional Mendelian randomization and mediation analysis

The roles of various immune cells and circulating inflammatory factors in neurodevelopmental disorders (NDDs) remain controversial. Therefore we employed a two-sample and bidirectional Mendelian randomization and mediation method to explore the causal relationships between immune cells, circulating inflammatory factors, and NDDs. All data were originated from Genome-Wide Association Study (GWAS) datasets. We found a significant positive causal relationship between 13 immune cells and autism spectrum disorder (ASD), including six CD8+ T cells, one CD3+ T cell, two CD20+ B cells, one CD38+  B cell, and two plasmacytoid DC. 9 inflammatory factors showed significant causal relationships with ASD: interleukins-7 (IL-7), interleukins-2 (IL-2), Interleukin-2 receptor subunit beta levels( IL-2β) and interleukins-18 receptor 1 levels (IL-18-R1) were negatively associated. In contrast, five inflammatory factors were positively associated, such as tumor necrosis factor-α (TNF-α). 14 immune cells exhibited significant causal relationships with attention deficit hyperactivity disorder (ADHD). CD3 on naive CD8br and CD4 on activated Treg were positively associated, while four CD27-expressing B cells were positively associated with ASD. Four CD40-expressing monocytes were negatively associated with ADHD. 7 inflammatory factors had significant causal relationships with ADHD: Fibroblast Growth Factor 23 levels (FGF-23), CD40L receptor levels, Glial Cell Line-Derived Neurotrophic Factor levels (GDNF), TNF-α were more important among these. Mediation analysis identified 12 mediating relationships, with three showing strong evidence: Natural killer cell receptor 2B4 levels (19.9%), FGF-23 (11%), and Eotaxin levels (- 5.95%). Strong causal relationships existed between immune cells, circulating inflammatory factors, and NDDs. Inflammatory factors mediated the pathways between immune cells and NDDs.

Peripheral Blood Monocytes as Biomarkers of Neurodevelopmental Disorders: A Systematic Review and Meta-Analysis

Accumulating evidence implicates immune dysregulation and chronic inflammation in neurodevelopmental disorders (NDDs), often manifesting as abnormal alterations in peripheral blood immune cell levels. The mononuclear phagocyte system, including monocytes and microglia, has been increasingly recognized for its involvement in the pathogenesis of NDDs. However, due to inconsistent findings in the literature, whether monocytes can serve as a reliable biomarker for NDDs remains controversial. To address this issue, we conducted a systematic review and meta-analysis of studies examining monocyte counts in NDD individuals. A comprehensive search was conducted across PubMed, Web of Science, and Scopus databases. Variables extracted for analysis encompassed the author's name, year of study, sample size, patient's age, type of disease, mean, standard deviation of monocytes and sex ratio. A total of 2503 articles were found by searching the three databases. After removed duplicates and screening titles, abstracts, and full texts, 17 articles met the inclusion criteria, and 20 independent studies were included in the meta-analysis. The results indicated significantly increased monocyte counts in 5 type NDDs compared to Typical Development (TD) groups (g = 0.36, 95%CI [0.23, 0.49]). Subgroup analyses revealed no significant differences in monocyte counts across different NDD types, gender, or age. These findings suggest that aberrant alterations in monocyte counts are common in NDD cases, indicating their potential as biomarkers for these conditions. Future research should further investigate the role of monocyte in understanding the mechanisms, early detection, and clinical diagnosis of NDDs.

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.