Risks of Major Mental Disorders and Irritable Bowel Syndrome among the Offspring of Parents with Irritable Bowel Syndrome: A Nationwide Study

Between Dysbiosis, Maternal Immune Activation and Autism: Is There a Common Pathway?

Autism spectrum disorder (ASD) is a neuropsychiatric condition characterized by impaired social interactions and repetitive stereotyped behaviors. Growing evidence highlights an important role of the gut-brain-microbiome axis in the pathogenesis of ASD. Research indicates an abnormal composition of the gut microbiome and the potential involvement of bacterial molecules in neuroinflammation and brain development disruptions. Concurrently, attention is directed towards the role of short-chain fatty acids (SCFAs) and impaired intestinal tightness. This comprehensive review emphasizes the potential impact of maternal gut microbiota changes on the development of autism in children, especially considering maternal immune activation (MIA). The following paper evaluates the impact of the birth route on the colonization of the child with bacteria in the first weeks of life. Furthermore, it explores the role of pro-inflammatory cytokines, such as IL-6 and IL-17a and mother's obesity as potentially environmental factors of ASD. The purpose of this review is to advance our understanding of ASD pathogenesis, while also searching for the positive implications of the latest therapies, such as probiotics, prebiotics or fecal microbiota transplantation, targeting the gut microbiota and reducing inflammation. This review aims to provide valuable insights that could instruct future studies and treatments for individuals affected by ASD.

The multi-generational familial aggregation of interstitial cystitis, other chronic nociplastic pain disorders, depression, and panic disorder

BACKGROUND

Interstitial cystitis/painful bladder syndrome (IC) is a chronic pelvic pain condition which has high comorbidity with other nociplastic, or unexplained, pain disorders [e.g. fibromyalgia (FM), irritable bowel syndrome (IBS), and myalgic encephalomyelitis/chronic fatigue (ME/CFS)] and some psychiatric conditions [major depressive disorder (MDD) and panic disorder (PD)]. Here we investigated the shared familiality of IC and these other nociplastic and psychiatric conditions.

METHODS

Subjects were identified in the Utah Population Database, which links genealogy data back to the 1800s to medical record diagnosis billing code data back to 1995. We computed the relative risk of each of these disorders among first (FDR), second (SDR), and third-degree relatives (TDR) of six proband groups: IC, FM, IBS, ME/CFS, PD, and MDD. Given the known familial aggregation of each of these disorders, we conducted our analyses to test for heritable interrelationships using proband subgroups whose members did not have the diagnosis assessed in their relatives.

RESULTS

We observed strong evidence for heritable interrelationships among all six disorders. Most analyses indicated significantly increased risk for each of the six disorders in FDR, SDR, and TDR of all or most proband groups. Out of 30 possible bidirectional disorder interrelationships, 26 were significant among FDR, 23 were significant among SDR, and 7 were significant among TDR. Clustering was observed in both close and distant relatives.

CONCLUSIONS

Our results support a common, heritable component to IC and other nociplastic and psychiatric conditions.

Shared genetic architecture between irritable bowel syndrome and psychiatric disorders reveals molecular pathways of the gut-brain axis

BACKGROUND

Irritable bowel syndrome (IBS) often co-occurs with psychiatric and gastrointestinal disorders. A recent genome-wide association study (GWAS) identified several genetic risk variants for IBS. However, most of the heritability remains unidentified, and the genetic overlap with psychiatric and somatic disorders is not quantified beyond genome-wide genetic correlations. Here, we characterize the genetic architecture of IBS, further, investigate its genetic overlap with psychiatric and gastrointestinal phenotypes, and identify novel genomic risk loci.

METHODS

Using GWAS summary statistics of IBS (53,400 cases and 433,201 controls), and psychiatric and gastrointestinal phenotypes, we performed bivariate casual mixture model analysis to characterize the genetic architecture and genetic overlap between these phenotypes. We leveraged identified genetic overlap to boost the discovery of genomic loci associated with IBS, and to identify specific shared loci associated with both IBS and psychiatric and gastrointestinal phenotypes, using the conditional/conjunctional false discovery rate (condFDR/conjFDR) framework. We used functional mapping and gene annotation (FUMA) for functional analyses.

RESULTS

IBS was highly polygenic with 12k trait-influencing variants. We found extensive polygenic overlap between IBS and psychiatric disorders and to a lesser extent with gastrointestinal diseases. We identified 132 independent IBS-associated loci (condFDR < 0.05) by conditioning on psychiatric disorders (n = 127) and gastrointestinal diseases (n = 24). Using conjFDR, 70 unique loci were shared between IBS and psychiatric disorders. Functional analyses of shared loci revealed enrichment for biological pathways of the nervous and immune systems. Genetic correlations and shared loci between psychiatric disorders and IBS subtypes were different.

CONCLUSIONS

We found extensive polygenic overlap of IBS and psychiatric and gastrointestinal phenotypes beyond what was revealed with genetic correlations. Leveraging the overlap, we discovered genetic loci associated with IBS which implicate a wide range of biological pathways beyond the gut-brain axis. Genetic differences may underlie the clinical subtype of IBS. These results increase our understanding of the pathophysiology of IBS which may form the basis for the development of individualized interventions.

Prevalence of Functional Gastrointestinal Disorders (Rome IV Criteria) among a Cohort of New Zealand Children

Functional gastrointestinal disorders (FGIDs) are characterised by recurring gastrointestinal symptoms that are not secondary to organic disease. FGIDs may cause reduced quality of life, with approximately 22% of children experiencing at least one FGID. This study aimed to assess FGID prevalence among children attending a tertiary care hospital in New Zealand (NZ). Methods: Children aged ≥ four years were prospectively recruited from Christchurch Hospital, NZ. Data were collected on demographics, medical history, gastrointestinal symptoms (Rome IV), and quality of life (EQ-5D-Y). An analysis was carried out using analysis of variance and the chi-squared test of independence. Results: The cohort included 156 children, with a mean age of 9.5 years (SD 3.3), 56% male. According to the Rome IV criteria, 29% experienced at least one FGID, most commonly functional constipation and functional dyspepsia. FGID symptoms were associated with Māori ethnicity (p = 0.012) and parental FGID (p < 0.001). Quality of life was lower in the FGID group in the domain ‘Feeling worried, sad, or unhappy’ (p = 0.002). Conclusion: the association of FGIDs with worse quality of life, in particular relating to worry and sadness, should highlight the importance of providing support to school age children experiencing FGID symptoms.

Exposure to Antibiotics and Neurodevelopmental Disorders: Could Probiotics Modulate the Gut-Brain Axis?

In order to develop properly, the brain requires the intricate interconnection of genetic factors and pre-and postnatal environmental events. The gut-brain axis has recently raised considerable interest for its involvement in regulating the development and functioning of the brain. Consequently, alterations in the gut microbiota composition, due to antibiotic administration, could favor the onset of neurodevelopmental disorders. Literature data suggest that the modulation of gut microbiota is often altered in individuals affected by neurodevelopmental disorders. It has been shown in animal studies that metabolites released by an imbalanced gut-brain axis, leads to alterations in brain function and deficits in social behavior. Here, we report the potential effects of antibiotic administration, before and after birth, in relation to the risk of developing neurodevelopmental disorders. We also review the potential role of probiotics in treating gastrointestinal disorders associated with gut dysbiosis after antibiotic administration, and their possible effect in ameliorating neurodevelopmental disorder symptoms.

Understanding the Role of the Gut Microbiome in Brain Development and Its Association With Neurodevelopmental Psychiatric Disorders

The gut microbiome has a tremendous influence on human physiology, including the nervous system. During fetal development, the initial colonization of the microbiome coincides with the development of the nervous system in a timely, coordinated manner. Emerging studies suggest an active involvement of the microbiome and its metabolic by-products in regulating early brain development. However, any disruption during this early developmental process can negatively impact brain functionality, leading to a range of neurodevelopment and neuropsychiatric disorders (NPD). In this review, we summarize recent evidence as to how the gut microbiome can influence the process of early human brain development and its association with major neurodevelopmental psychiatric disorders such as autism spectrum disorders, attention-deficit hyperactivity disorder, and schizophrenia. Further, we discuss how gut microbiome alterations can also play a role in inducing drug resistance in the affected individuals. We propose a model that establishes a direct link of microbiome dysbiosis with the exacerbated inflammatory state, leading to functional brain deficits associated with NPD. Based on the existing research, we discuss a framework whereby early diet intervention can boost mental wellness in the affected subjects and call for further research for a better understanding of mechanisms that govern the gut-brain axis may lead to novel approaches to the study of the pathophysiology and treatment of neuropsychiatric disorders.

Association between breakfast consumption frequency and the risk of irritable bowel syndrome among Chinese female college students: A cross-sectional study

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder that affects specific groups of people. The relationship between breakfast consumption frequency and the risk of IBS is unclear. This study aimed to investigate the association between breakfast consumption frequency and the risk of IBS among Chinese female college students.In this cross-sectional study (n = 706) conducted in October 2018, the frequency of breakfast consumption was categorized as 0 to 3 times/week, 4 to 6 times/week, or daily. IBS was diagnosed according to the Rome III criteria and was based on the presence of abdominal pain or discomfort for at least 3 months during the previous 6 months, with at least 2 or more of the following conditions: changes in frequency or form of stool and/or decrease in pain after defecation. We adjusted for confounding factors, including age, only child (yes or no), parents' educational levels (senior high school or below, college, or postgraduate), parents' marital status (married, widowed, or divorced), smoking status (smoker or nonsmoker), drinking status (drinker or nondrinker), body mass index, and depressive symptoms. A multiple logistic regression analysis was performed to determine the relationship between breakfast frequency and the risk of IBS.Among 706 participants, 23.7% were the only child in their family, and the proportion of parents divorced or widowed was 18.5%. The proportion of fathers and mothers with high school education or above was 93.3% and 96.3%, respectively. The prevalence of IBS among the participants was 17.3% (122/706). Multivariate logistic regressions analysis showed that breakfast consumption frequency is negatively associated with the risk of IBS after adjusting for confounding factors. The odds ratios (95% confidence intervals) for IBS in the breakfast frequency category of 0 to 3 times/week, 4 to 6 times/week, and daily were 1.00 (reference), 0.96 (0.58, 1.60), and 0.45 (0.26, 0.78), respectively (P = .002).Our data revealed that regular breakfast consumption is associated with a lower risk of IBS among Chinese college students. Future cohort and/or interventional studies should be conducted to further explore the association between breakfast consumption frequency and IBS.