Autism spectrum disorder and kidney disease

Neurodevelopmental profile of infants and toddlers awaiting a kidney transplant

BACKGROUND

Infants and toddlers with kidney failure are susceptible to neurodevelopmental delays due to medical comorbidities and rapid brain development in early childhood. However, research on the neuropsychological development of this patient population has been limited over the past 10 years.

METHODS

We performed a retrospective study to evaluate the neurodevelopmental functioning of infants/toddlers with kidney failure who completed the Bayley Scales of Infant and Toddler Development (3rd and 4th Edition) as part of a pretransplant evaluation between 2010 and 2022 (n = 23; Mage = 18 months, SD = 8.53; 16 males) using t-tests, linear model, and Pearson correlations.

RESULTS

Mean Bayley scores of participants were below normative means for cognition (M = 86.74, 95% CI = 80.53-92.94, p < 0.001), language (M = 79.20, 95% CI = 73.32-85.08, p < 0.001), and motor (M = 78.00, 95% CI = 70.15-85.85, p < 0.001) domains. After adjusting for prematurity and epilepsy, patients on dialysis had significantly lower cognitive (78.7 vs. 93.8; p = 0.001) and motor scores (67.1 vs. 85.5; p = 0.01) compared to no dialysis. Pretransplant cognitive scores were positively correlated with posttransplant Full-Scale IQ (r(8) = 0.65 p = 0.04), verbal comprehension (r(8) = 0.75 p = 0.02), and fluid reasoning (r(7) = 0.68 p = 0.045). Similarly, pretransplant language scores were positively correlated with posttransplant Full-Scale IQ (r(7) = 0.74 p = 0.03) and verbal comprehension (r(7) = 0.73 p = 0.03). Of the 16 participants who reached age > 5 years during the study period, seven were diagnosed with a neurodevelopmental disorder, including three with autism spectrum disorder.

CONCLUSIONS

Infants and toddlers with kidney failure are at risk of developmental delays and later neurodevelopmental disorders. Dialysis is associated with cognitive and motor delays independent of prematurity and epilepsy.

Shared genetic effect of kidney function on bipolar and major depressive disorders: a large-scale genome-wide cross-trait analysis

BACKGROUND

Epidemiological studies have revealed a significant association between impaired kidney function and certain mental disorders, particularly bipolar disorder (BIP) and major depressive disorder (MDD). However, the evidence regarding shared genetics and causality is limited due to residual confounding and reverse causation.

METHODS

In this study, we conducted a large-scale genome-wide cross-trait association study to investigate the genetic overlap between 5 kidney function biomarkers (eGFRcrea, eGFRcys, blood urea nitrogen (BUN), serum urate, and UACR) and 2 mental disorders (MDD, BIP). Summary-level data of European ancestry were extracted from UK Biobank, Chronic Kidney Disease Genetics Consortium, and Psychiatric Genomics Consortium.

RESULTS

Using LD score regression, we found moderate but significant genetic correlations between kidney function biomarker traits on BIP and MDD. Cross-trait meta-analysis identified 1 to 19 independent significant loci that were found shared among 10 pairs of 5 kidney function biomarkers traits and 2 mental disorders. Among them, 3 novel genes: SUFU, IBSP, and PTPRJ, were also identified in transcriptome-wide association study analysis (TWAS), most of which were observed in the nervous and digestive systems (FDR < 0.05). Pathway analysis showed the immune system could play a role between kidney function biomarkers and mental disorders. Bidirectional mendelian randomization analysis suggested a potential causal relationship of kidney function biomarkers on BIP and MDD.

CONCLUSIONS

In conclusion, the study demonstrated that both BIP and MDD shared genetic architecture with kidney function biomarkers, providing new insights into their genetic architectures and suggesting that larger GWASs are warranted.

BugSigDB captures patterns of differential abundance across a broad range of host-associated microbial signatures

The literature of human and other host-associated microbiome studies is expanding rapidly, but systematic comparisons among published results of host-associated microbiome signatures of differential abundance remain difficult. We present BugSigDB, a community-editable database of manually curated microbial signatures from published differential abundance studies accompanied by information on study geography, health outcomes, host body site and experimental, epidemiological and statistical methods using controlled vocabulary. The initial release of the database contains >2,500 manually curated signatures from >600 published studies on three host species, enabling high-throughput analysis of signature similarity, taxon enrichment, co-occurrence and coexclusion and consensus signatures. These data allow assessment of microbiome differential abundance within and across experimental conditions, environments or body sites. Database-wide analysis reveals experimental conditions with the highest level of consistency in signatures reported by independent studies and identifies commonalities among disease-associated signatures, including frequent introgression of oral pathobionts into the gut.

Common mental health conditions and considerations in pediatric chronic kidney disease

The mental health of youth with chronic kidney disease (CKD) has been increasingly recognized as an area of clinical need. The development of mental health concerns is influenced by a range of physiological, psychological, and environmental factors. Some of these factors are common across child development, but some are more unique to youth with CKD. Mental health concerns are associated with increased risk for a range of poor medical outcomes (e.g., adherence, risk of transplant rejection) and quality of life concerns. In this educational review, we discuss the current evidence base regarding the development of mental health concerns in youth with CKD. The review covers multiple domains including mood and anxiety disorders, traumatic stress, and neurodevelopmental disorders. Estimated prevalence and hypothesized risk factors are outlined, and the potential impact of mental health on medical care and functional outcomes are reviewed. Finally, we introduce options for intervention to support positive mental health and offer recommendations for building access to mental health care and improving the mental health education/training of medical professionals.

4-Ethylphenol-fluxes, metabolism and excretion of a gut microbiome derived neuromodulator implicated in autism

Gut-microbiome-derived metabolites, such as 4-Ethylphenol [4EP], have been shown to modulate neurological health and function. Although the source of such metabolites is becoming better understood, knowledge gaps remain as to the mechanisms by which they enter host circulation, how they are transported in the body, how they are metabolised and excreted, and the way they exert their effects. High blood concentrations of host-modified 4EP, 4-ethylphenol sulfate [4EPS], are associated with an anxiety phenotype in autistic individuals. We have reviewed the existing literature and discuss mechanisms that are proposed to contribute influx from the gut microbiome, metabolism, and excretion of 4EP. We note that increased intestinal permeability is common in autistic individuals, potentially explaining increased flux of 4EP and/or 4EPS across the gut epithelium and the Blood Brain Barrier [BBB]. Similarly, kidney dysfunction, another complication observed in autistic individuals, impacts clearance of 4EP and its derivatives from circulation. Evidence indicates that accumulation of 4EPS in the brain of mice affects connectivity between subregions, particularly those linked to anxiety. However, we found no data on the presence or quantity of 4EP and/or 4EPS in human brains, irrespective of neurological status, likely due to challenges sampling this organ. We argue that the penetrative ability of 4EP is dependent on its form at the BBB and its physicochemical similarity to endogenous metabolites with dedicated active transport mechanisms across the BBB. We conclude that future research should focus on physical (e.g., ingestion of sorbents) or metabolic mechanisms (e.g., conversion to 4EP-glucuronide) that are capable of being used as interventions to reduce the flux of 4EP from the gut into the body, increase the efflux of 4EP and/or 4EPS from the brain, or increase excretion from the kidneys as a means of addressing the neurological impacts of 4EP.

Vasopressin as Possible Treatment Option in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is rather common, presenting with prevalent early problems in social communication and accompanied by repetitive behavior. As vasopressin was implicated not only in salt-water homeostasis and stress-axis regulation, but also in social behavior, its role in the development of ASD might be suggested. In this review, we summarized a wide range of problems associated with ASD to which vasopressin might contribute, from social skills to communication, motor function problems, autonomous nervous system alterations as well as sleep disturbances, and altered sensory information processing. Beside functional connections between vasopressin and ASD, we draw attention to the anatomical background, highlighting several brain areas, including the paraventricular nucleus of the hypothalamus, medial preoptic area, lateral septum, bed nucleus of stria terminalis, amygdala, hippocampus, olfactory bulb and even the cerebellum, either producing vasopressin or containing vasopressinergic receptors (presumably V1a). Sex differences in the vasopressinergic system might underline the male prevalence of ASD. Moreover, vasopressin might contribute to the effectiveness of available off-label therapies as well as serve as a possible target for intervention. In this sense, vasopressin, but paradoxically also V1a receptor antagonist, were found to be effective in some clinical trials. We concluded that although vasopressin might be an effective candidate for ASD treatment, we might assume that only a subgroup (e.g., with stress-axis disturbances), a certain sex (most probably males) and a certain brain area (targeting by means of virus vectors) would benefit from this therapy.

Dysregulated phosphate metabolism in autism spectrum disorder: associations and insights for future research

Studies of autism spectrum disorder (ASD) related to exposure to toxic levels of dietary phosphate are lacking. Phosphate toxicity from dysregulated phosphate metabolism can negatively impact almost every major organ system of the body, including the central nervous system. The present paper used a grounded theory-literature review method to synthesise associations of dysregulated phosphate metabolism with the aetiology of ASD. Cell signalling in autism has been linked to an altered balance between phosphoinositide kinases, which phosphorylate proteins, and the counteracting effect of phosphatases in neuronal membranes. Glial cell overgrowth in the developing ASD brain can lead to disturbances in neuro-circuitry, neuroinflammation and immune responses which are potentially related to excessive inorganic phosphate. The rise in ASD prevalence has been suggested to originate in changes to the gut microbiome from increasing consumption of additives in processed food, including phosphate additives. Ketogenic diets and dietary patterns that eliminate casein also reduce phosphate intake, which may account for many of the suggested benefits of these diets in children with ASD. Dysregulated phosphate metabolism is causatively linked to comorbid conditions associated with ASD such as cancer, tuberous sclerosis, mitochondrial dysfunction, diabetes, epilepsy, obesity, chronic kidney disease, tauopathy, cardiovascular disease and bone mineral disorders. Associations and proposals presented in this paper offer novel insights and directions for future research linking the aetiology of ASD with dysregulated phosphate metabolism and phosphate toxicity from excessive dietary phosphorus intake.

Risk of dialysis and renal diseases in patients with anorexia nervosa in Taiwan

OBJECTIVE

To investigate the incidence and risk of renal-related complications in a nationwide cohort of Taiwanese patients with anorexia nervosa (AN).

METHOD

This longitudinal cohort study analyzed the data of 43,951 individuals-comprising 2091 patients with AN and their controls matched (1:20) using propensity scores according to sex, age, degree of urbanization of residence, socioeconomic status, and year of diagnosis-from a population-based health insurance database; the study lasted 16 years. We used Kaplan-Meier curves to estimate the cumulative incidence of renal events. We also performed Cox proportional regression and constructed a risk model with death as a competing event (both adjusted for basic characteristics, renal diseases, and psychiatric comorbidities) to examine the risk of dialysis and renal outcomes in the AN group relative to the control group.

RESULTS

In total, 204 and 10 patients with AN had renal-related outcomes and end-stage renal disease (ESRD), respectively. The cumulative incidence rates of all renal outcomes and ESRD in the AN group were 10.72% and .64%, respectively, at 10-year follow-up. Compared with the control group, the AN group had a significantly higher risk of acute dialysis (adjusted hazard ratio 2.10 [95% confidence interval 1.19-3.68]), hypokalemia, hypovolemia, nephritis, acute renal failure, and chronic renal failure. The AN group did not have a significantly higher risk of ESRD.

DISCUSSION

The elevated risks of acute dialysis and some renal outcomes in AN highlight the importance of monitoring electrolyte imbalance and renal malfunctioning.

PUBLIC SIGNIFICANCE

Malnutrition and purging behaviors may cause renal complications in patients with AN. In this longitudinal cohort study, we found that the 10-year cumulative incidence of all renal outcomes in AN was 10.72%, and that patients with AN had a two-fold higher risk of overall renal outcomes compared with those without AN. Our findings imply that weight restoration and ceasing purging behaviors are crucial for recovery from AN.

Multimorbidity patterns and subgroups among autistic adults with intellectual disability: Results from the EFAAR study

LAY ABSTRACT

Multimorbidity relates to having multiple chronic health conditions. It is a risk factor for poor health and reduces life expectancy. Autistic people have multiple chronic health conditions and die prematurely, especially if they have an intellectual disability (autism spectrum disorder and intellectual disability). Certain pathophysiological processes observed in autism spectrum disorder are common to those related to the genesis and/or maintenance of multimorbidity. Furthermore, multimorbidity could be helpful in better identifying patient subgroups in autism spectrum disorder. It is therefore essential to better characterize multimorbidity and its consequences in the subgroup of autism spectrum disorder + intellectual disability individuals to offer them personalized care. We conducted a preliminary study of 63 autism spectrum disorder + intellectual disability adults to classify them according to their multimorbidity and search for a specific combination of chronic health conditions. We observed high and early multimorbidity in this sample and identified four classes of participants, distinguished by their multimorbidity status, independence and number of treatments. In addition, we observed a dominant combination of multimorbidity in our sample, combining immune dysfunction and gastrointestinal disorders, neurological and joint diseases. These findings support the hypothesis that an altered gut-brain relationship is involved in the risk of autism spectrum disorder, its outcome, and its association with chronic health conditions. Although larger studies are needed, our results suggest that subgroups of autism spectrum disorder + intellectual disability individuals can be identified based on their multimorbidity and potentially different ageing trajectories. A more comprehensive and personalized approach is needed to reduce the burden of multimorbidity and increase the quality of life and life expectancy in autism spectrum disorder/ intellectual disability.

The association of neurodevelopmental abnormalities, congenital heart and renal defects in a tuberous sclerosis complex patient cohort

BACKGROUND

Tuberous sclerosis complex (TSC) is a rare multi-system genetic disorder characterised by the presence of benign tumours throughout multiple organs including the brain, kidneys, heart, liver, eyes, lungs and skin, in addition to neurological and neuropsychiatric complications. Intracardiac tumour (rhabdomyoma), neurodevelopmental disorders (NDDs) and kidney disorders (KD) are common manifestations of TSC and have been linked with TSC1 and TSC2 loss-of-function mutations independently, but the dynamic relationship between these organ manifestations remains unexplored. Therefore, this study aims to characterise the nature of the relationship specifically between these three organs' manifestations in TSC1 and TSC2 mutation patients.

METHODS

Clinical data gathered from TSC patients across South Wales registered with Cardiff and Vale University Health Board (CAV UHB) between 1990 and 2020 were analysed retrospectively to evaluate abnormalities in the heart, brain and kidney development. TSC-related abnormalities such as tumour prevalence, location and size were analysed for each organ in addition to neuropsychiatric involvement and were compared between TSC1 and TSC2 mutant genotypes. Lastly, statistical co-occurrence between organ manifestations co-morbidity was quantified, and trajectories of disease progression throughout organs were modelled.

RESULTS

This study found a significantly greater mutational frequency at the TSC2 locus in the cohort in comparison to TSC1. An equal proportion of male and female patients were observed in this group and by meta-analysis of previous studies. No significant difference in characterisation of heart involvement was observed between TSC1 and TSC2 patients. Brain involvement was seen with increased severity in TSC2 patients, characterised by a greater prevalence of cortical tubers and communication disorders. Renal pathology was further enhanced in TSC2 patients, marked by increased bilateral angiomyolipoma prevalence. Furthermore, co-occurrence of NDDs and KDs was the most positively correlated out of investigated manifestations, regardless of genotype. Analysis of disease trajectories revealed a more diverse clinical outcome for TSC2 patients: however, a chronological association of rhabdomyoma, NDD and KD was most frequently observed for TSC1 patients.

CONCLUSIONS

This study marks the first empirical investigation of the co-morbidity between congenital heart defects (CHD), NDDs, and KDs in TSC1 and TSC2 patients. This remains a unique first step towards the characterisation of the dynamic role between genetics, heart function, brain function and kidney function during the early development in the context of TSC.

Screening for Hypertension in Children With and Without Autism Spectrum Disorder

This cross-sectional study compares the frequency of hypertension screening at health maintenance visits between children with and without autism.

Haploinsufficiency of the mouse Tshz3 gene leads to kidney defects

Renal tract defects and autism spectrum disorder (ASD) deficits represent the phenotypic core of the 19q12 deletion syndrome caused by the loss of one copy of the TSHZ3 gene. While a proportion of Tshz3 heterozygous (Tshz3+/lacZ) mice display ureteral defects, no kidney defects have been reported in these mice. The purpose of this study was to characterize the expression of Tshz3 in adult kidney as well as the renal consequences of embryonic haploinsufficiency of Tshz3 by analyzing the morphology and function of Tshz3 heterozygous adult kidney. Here, we described Tshz3 expression in the smooth muscle and stromal cells lining the renal pelvis, the papilla and glomerular endothelial cells (GEnCs) of the adult kidney as well as in the proximal nephron tubules in neonatal mice. Histological analysis showed that Tshz3+/lacZ adult kidney had an average of 29% fewer glomeruli than wild type kidney. Transmission electron microscopy (TEM) of Tshz3+/lacZ glomeruli revealed a reduced thickness of the glomerular basement membrane and a larger foot process width. Compared to wild type, Tshz3+/lacZ mice showed lower blood urea, phosphates, magnesium and potassium at 2 months of age. At the molecular level, transcriptome analysis identified differentially expressed genes related to inflammatory processes in Tshz3+/lacZ compare to wild type (WT; control) adult kidneys. Lastly, analysis of the urinary peptidome revealed 33 peptides associated with Tshz3+/lacZ adult mice. These results provide the first evidence that in the mouse Tshz3 haploinsufficiency leads to cellular, molecular and functional abnormalities in the adult mouse kidney.