Alterations in the histological features of the intestinal mucosa in malnourished adults of Bangladesh

Alteration of stool pH and its association with biomarkers of gut enteropathy among slum-dwelling women of reproductive age in Bangladesh

BACKGROUND

Recent evidence suggests that measures of maternal gut enteropathy are associated with unfavorable fetal outcomes. It is, therefore, crucial to identify and treat the features of intestinal enteropathy among reproductive-age women living in areas where enteropathy is highly prevalent. However, there is a lack of non-invasive diagnostic tests to determine EED, making it difficult to identify the disease in field settings. In this study, we tested the potential of fecal pH as a biomarker of gut enteropathy and investigated its relationship with fecal biomarkers of intestinal enteropathy in reproductive-age women living in resource-limited environments.

METHODS

Data on socio-demographic information, anthropometry, and biological samples were collected from 78 apparently healthy women aged between 20 and 27 years from November 2018 to December 2019. The association of stool pH with two fecal biomarkers of gut enteropathy (i.e., intestinal alkaline phosphatase [IAP] and fecal lipocalin-2 [LCN-2] was investigated using multiple linear regression models after adjusting for relevant covariates.

RESULTS

In the adjusted models, alkaline stool pH (pH > 7.2) was found to be significantly associated with a decrease in the fecal IAP level by 1.05 unit (95% CI: -1.68, -0.42; p < 0.001) in the log scale, and acidic stool pH (pH < 6) was found to be significantly associated with an increase in the fecal LCN-2 level by 0.89 units (95% CI: 0.12, 1.67; p < 0.025) in the log scale.

CONCLUSIONS

The study findings demonstrated an association of fecal pH with biomarkers of gut enteropathy indicating its applicability as a simple tool for understanding intestinal enteropathy among reproductive-age women living in resource-limited settings.

Multistrain probiotic rescinds quinpirole-induced obsessive-compulsive disorder phenotypes by reshaping of microbiota gut-brain axis in rats

Obsessive-compulsive disorder (OCD) is a disabling mental condition that poses recurring bothersome intrusive thoughts, obsessions, and compulsions. Considering the positive impact of probiotics on neuropsychiatric disorders, herein, we investigated the effect of multistrain probiotic (Bifidobacterium lactis UBBLa-70, Bacillus coagulans Unique IS-2, Lactobacillus rhamnosus UBLR-58, Lactobacillus plantarum UBLP-40, Bifidobacterium infantis UBBI-01, Bifidobacterium breve UBBr-01, and glutamine) in the management of OCD-like phenotype in rats. Rats injected with quinpirole for 5 weeks showed an increased number of marble burying and self-grooming episodes. Quinpirole-injected animals also did less head dipping in the hole board test and avoided exploration of open spaces in the elevated-plus maze. These repetitive, compulsive, self-directed, and anxiety-like phenotypes were abolished after 8-week of multistrain probiotic treatment. The probiotic formulation also prevented the elevated mRNA expression of interleukin-6, tumor-necrosis factor-α, and C-reactive protein in the amygdala and dysregulated levels of 5-hydroxytryptamine, dopamine, and noradrenaline in the frontal cortex of quinpirole-injected rats. The level of brain-derived neurotrophic factor in the frontal cortex remained unaffected across the groups. The altered levels of goblet cells and crypt-to-villi ratio in quinpirole rats were prevented by multistrain probiotic treatment. The results of 16S-rRNA gene-sequencing of gut microbiota from feces contents revealed an elevation in the abundance of Allobaculum and Bifidobacterium species (specifically Bifidobacterium animalis), while the presence of Lactobacillus species (including Lactobacillus reuteri and Lactobacillus vaginalis) exhibited a decline in quinpirole-induced rats. These results imply that modifying the gut-brain axis may be a possible mechanism by which selective multistrain probiotic therapy prevents OCD-like behaviors.

Ameliorating role of Tetrastigma hemsleyanum polysaccharides in antibiotic-induced intestinal mucosal barrier dysfunction in mice based on microbiome and metabolome analyses

The intestinal mucosal barrier is one of the important barriers to prevent harmful substances and pathogens from entering the body environment and to maintain intestinal homeostasis. This study investigated the reparative effect and possible mechanism of Tetrastigma hemsleyanum polysaccharides (THP) on ceftriaxone-induced intestinal mucosal damage. Our results suggested that THP repaired the mechanical barrier damage of intestinal mucosa by enhancing the expression of intestinal tight junction proteins, reducing intestinal mucosal permeability and improving the pathological state of intestinal epithelial cells. Intestinal immune and chemical barrier was further restored by THP via the increment of the body's cytokine levels, intestinal SIgA levels, intestinal goblet cell number, intestinal mucin-2 levels, and short-chain fatty acid levels. In addition, THP increased the abundance of probiotic bacteria (such as Lactobacillus), reduced the abundance of harmful bacteria (such as Enterococcus) to repair the intestinal biological barrier, restored intestinal mucosal barrier function, and maintains intestinal homeostasis. The possible mechanisms were related to sphingolipid metabolism, linoleic acid metabolism, and d-glutamine and D-glutamate metabolism. Our results demonstrated the potential therapeutic effect of THP against intestinal flora disorders and intestinal barrier function impairment caused by antibiotics.

Environmental enteric dysfunction and small intestinal histomorphology of stunted children in Bangladesh

There is lack of information on the histological characteristics of the intestinal mucosa in Bangladeshi children. Collection of intestinal biopsy samples and assessment of the histomorphological features is considered to be the traditional gold standard for diagnosis of environmental enteric dysfunction (EED). The purpose of the study was to evaluate the intestinal histological characteristics of stunted children aged between 12-18 months with possible EED. 110 children with chronic malnutrition (52 stunted with length-for-age Z score, LAZ<-2 and 58 at risk of stunting with LAZ <-1 to -2) from the Bangladesh Environmental Enteric Dysfunction (BEED) study protocol who underwent upper gastrointestinal (GI) endoscopy were selected for this study. To explore the association of EED with childhood stunting, upper GI endoscopy was done and the biopsy specimens were studied for histopathology. Villous height and crypt depth were measured and the presence and intensity of inflammatory infiltrates in the lamina propria was investigated. Bivariate analysis was performed to examine the relationship between stunting and histologic morphology. More than 90% children irrespective of nutritional status were diagnosed to have chronic non-specific duodenitis on histopathology. Half of the children from both groups had villous atrophy as well as crypt hyperplasia and lymphocytic infiltration was present in more than 90% children, irrespective of groups. However, no statistically significant difference was observed when compared between the groups. The prevalence of chronic non-specific duodenitis in Bangladeshi children, irrespective of nutritional status, was high. A significant number of these children had abnormal findings in intestinal histomorphology. Trial registration number: ClinicalTrials.gov ID: NCT02812615 Date of first registration: 24/06/2016. https://clinicaltrials.gov/ct2/results?cond=NCT02812615&term=&cntry=&state=&city=&dist.

Maternal and child FUT2 and FUT3 status demonstrate relationship with gut health, body composition and growth of children in Bangladesh

Fucosyltransferase 2 (FUT2) and 3 (FUT3) may influence host biological functions. We aim to assess the relationship between maternal and child FUT2 (Secretor) and FUT3 (Lewis) status with growth, body composition, gut health and histologic features in Bangladeshi children. We conducted a case-control study where secretor and Lewis status were ascertained from saliva samples of 408 mother-child dyads. Upper-arm fat area estimate (UFE) and total upper arm area (TUA) were found higher among children of Lewis negative mothers (p = 0.01 and p = 0.07, respectively). Changes in UFE after nutrition intervention were significantly greater among Lewis positive children than those of negative for Lewis (p = 0.05). Significant differences were observed for child UFE based on secretor and Lewis status of the mothers (p = 0.04). Lewis positive children had greater changes in WAZ (p = 0.07) and WLZ (p = 0.02) than Lewis negative children at the end of nutrition intervention. Fecal Reg1B was elevated in secretor positive children compared to their counterparts (p = 0.03). Lewis negative children had higher concentrations of MPO compared to Lewis positive children (p = 0.08). We also observed a higher frequency of subtotal villous atrophy among secretor negative and Lewis positive children (p = 0.09 and p = 0.01, respectively) than those of their counterparts. The findings provide insights for further studies to elucidate causal influences.

Heat Stress-Mediated Activation of Immune-Inflammatory Pathways

Physiological changes in animals exposed to elevated ambient temperature are characterized by the redistribution of blood toward the periphery to dissipate heat, with a consequent decline in blood flow and oxygen and nutrient supply to splanchnic tissues. Metabolic adaptations and gut dysfunction lead to oxidative stress, translocation of lumen contents, and release of proinflammatory mediators, activating a systemic inflammatory response. This review discusses the activation and development of the inflammatory response in heat-stressed models.

Gut integrity and duodenal enteropathogen burden in undernourished children with environmental enteric dysfunction

Environmental enteric dysfunction (EED) is a subclinical condition of intestinal inflammation, barrier dysfunction and malabsorption associated with growth faltering in children living in poverty. This study explores association of altered duodenal permeability (lactulose, rhamnose and their ratio) with higher burden of enteropathogen in the duodenal aspirate, altered histopathological findings and higher morbidity (diarrhea) that is collectively associated with linear growth faltering in children living in EED endemic setting. In a longitudinal birth cohort, 51 controls (WHZ > 0, HAZ > −1.0) and 63 cases (WHZ< -2.0, refractory to nutritional intervention) were recruited. Anthropometry and morbidity were recorded on monthly bases up to 24 months of age. Dual sugar assay of urine collected after oral administration of lactulose and rhamnose was assessed in 96 children from both the groups. Duodenal histopathology (n = 63) and enteropathogen analysis of aspirate via Taqman array card (n = 60) was assessed in only cases. Giardia was the most frequent pathogen and was associated with raised L:R ratio (p = 0.068). Gastric microscopy was more sensitive than duodenal aspirate in H. pylori detection. Microscopically confirmed H. pylori negatively correlated with HAZ at 24 months (r = −0.313, p = 0.013). Regarding histopathological parameters, goblet cell reduction significantly correlated with decline in dual sugar excretion (p< 0.05). Between cases and controls, there were no significant differences in the median (25^th, 75^th percentile) of urinary concentrations (μg/ml) of lactulose [27.0 (11.50, 59.50) for cases vs. 38.0 (12.0, 61.0) for controls], rhamnose [66.0 (28.0, 178.0) vs. 86.5 (29.5, 190.5)] and L:R ratio [0.47 (0.24, 0.90) vs. 0.51 (0.31, 0.71)] respectively. In multivariable regression model, 31% of variability in HAZ at 24 months of age among cases and controls was explained by final model including dual sugars. In conclusion, enteropathogen burden is associated with altered histopathological features and intestinal permeability. In cases and controls living in settings of endemic enteropathy, intestinal permeability test may predict linear growth. However, for adoption as a screening tool for EED, further validation is required due to its complex intestinal pathophysiology.

EED is a subclinical condition of compromised gut integrity secondary to frequent and repeated exposure to enteropathogens in global settings with a high prevalence of undernutrition. In this study, we reported association of gut mucosal architecture with a dual sugar intestinal permeability assay (lactulose-rhamnose) in Pakistani children. In the presence of duodenal enteropathogens, features such as chronic inflammation, intra-epithelial lymphocytosis, enterocyte injury and Paneth cell reduction were consistently observed. When comparing undernourished cases and controls living in the same setting, we found urinary excretion of the sugars was similar among groups; however, variability in HAZ among children at 24 months was partially explained by a model that includes excretion values.