Acute haemodynamic changes during haemodialysis do not exacerbate gut hyperpermeability

Gut microbiota associations with chronic kidney disease: insights into nutritional and inflammatory parameters

Introduction

The gut barrier, comprising gut microbiota, plays a pivotal role in chronic kidney disease (CKD) progression and nutritional status. This study aimed to explore gut barrier alterations in hemodialyzed (HD) patients, non-HD (NHD) CKD patients, and healthy volunteers.

Methods

Our cross-sectional study enrolled 22 HD patients, 11 NHD patients, and 11 healthy volunteers. We evaluated fecal microbiota composition (assessed via bacterial 16S rRNA gene sequencing), fecal IgA levels, surrogate markers of gut permeability, serum cytokines, appetite mediators, nutritional status, physical activity, and quality of life.

Results

HD patients exhibited significant alterations in fecal microbiota composition compared to healthy volunteers, with observed shifts in taxa known to be associated with dietary patterns or producing metabolites acting on human host. In comparison to healthy volunteers, individuals with HD patients exhibited elevated levels of inflammatory markers (CRP, IL-6 and TNF-α), glucagon-like peptide-2, and potential anorexigenic markers (including leptin and peptide YY). NHD patients had increased levels of CRP and peptide YY. Overall fecal microbiota composition was associated with height, soft lean mass, resting energy expenditure, handgrip strength, bone mineral content and plasma albumin and TNF-α.

Discussion

Compared to healthy volunteers, HD patients have an altered fecal microbiota composition, a higher systemic inflammation, and a modification in plasma levels of appetite mediators. While some differences align with previous findings, heterogeneity exists likely due to various factors including lifestyle and comorbidities. Despite limitations such as sample size, our study underscores the multifaceted interplay between gut microbiota, physiological markers, and kidney function, warranting further investigation in larger cohorts.

Plasma measurements of the dual sugar test reveal carbohydrate immediately alleviates intestinal permeability caused by exertional heat stress

The aim of this set of randomised cross-over studies was to determine the impact of progressive heat exposure and carbohydrate or protein feeding during exertional stress on small intestine permeability using a dual sugar test. In our previous work, and typically in the field, recovery of lactulose and l-rhamnose is measured cumulatively in urine. This follow-up study exploits our novel high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) protocol to accurately quantify the sugars in plasma. Endurance-trained participants completed experimental trial A (ET-A; n = 8), consisting of 2 h running at 60%V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ in temperate, warm and hot ambient conditions, and/or experimental trial B (ET-B; n = 9), consisting of 2 h running at 60%V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ in the heat while consuming water, carbohydrate or protein. Blood samples were collected and plasma lactulose (L) and l-rhamnose (R) appearance, after dual sugar solution ingestion at 90 min of exercise, was quantified by HPAEC-PAD to measure plasma L/R and reveal new information about intestinal permeability immediately post-exercise and during recovery. In ET-A, plasma L/R increased immediately post-exercise in hot compared with temperate and warm conditions, while, in ET-B, carbohydrate alleviated this, and this information was otherwise missed when measuring urine L/R. Consuming carbohydrate or protein before and during exercise attenuated small intestine permeability throughout recovery from exertional heat stress. We recommend using the dual sugar test with quantification of plasma sugars by HPAEC-PAD at intervals to maximise intestinal permeability data collection in exercise gastroenterology research, as this gives additional information compared to urinary measurements. KEY POINTS: Intestinal permeability is typically assessed using a dual sugar test, by administering a drink containing non-metabolisable sugars (e.g. lactulose (L) and l-rhamnose (R)) that can enter the circulation by paracellular translocation when the epithelium is compromised, and are subsequently measured in urine. We demonstrate that our recently developed ion chromatography protocol can be used to accurately quantify the L/R ratio in plasma, and that measuring L/R in plasma collected at intervals during the post-exercise recovery period reveals novel acute response information compared to measuring 5-h cumulative urine L/R. We confirm that exercising in hot ambient conditions increases intestinal epithelial permeability immediately after exercise, while consuming carbohydrate or protein immediately before and during exercise attenuates this. We recommend using our dual sugar absorption test protocol to maximise intestinal epithelial permeability data collection in exercise gastroenterology research and beyond.

Assessment of Gut leakage Induced Systemic Inflammation in Children on Chronic Hemodialysis

BACKGROUND: Children with chronic kidney disease (CKD) are at high risk to develop GIT complications such as intestinal wall edema and increased permeability which contributes to chronic systemic inflammation that increases morbidity and mortality burden. AIM: This study aim was to show the relationship between inflammation and increased intestinal permeability in children on hemodialysis (HD). METHODS: The study included 50 children with CKD on regular HD of variable duration; their age range was (5−16) years and 40 controls. They were followed up at Nephrology clinic- Eldemerdash hospital. Complete history taking, physical examination were done. Laboratory measurement in the form of zonulin, tumor necrosis factor-alpha (TNF-alpha), high sensitive C-reactive protein (hs-CRP), and alpha1-antitrypsin (AAT) were quantified in serum by ELISA method. RESULTS: There was a highly significant decrease in anthropometric measures (weight, height and BMI) and their corresponding z score in cases compared to controls with p ≤ 0.001. Furthermore, there was significant increase of levels of zonulin, TNF-alpha, AAT, and hs-CRP in cases compared to controls with p value of 0.009, 0.001, 0.002, and 0.003, respectively. There was significant positive correlation between zonulin and (TNF-alpha, AAT, hs-CRP, and creatinine) with P values (0.003, 0.001, 0.001, and 0.001), respectively. Zonulin is negatively correlated with weight for age Z score (WAZ) and height with p value (0.01 and 0.018), respectively. TNF-alpha and hs-CRP were negatively correlated with WAZ with P-values of 0.02 and 0.01, respectively. CONCLUSION: Children with CKD on chronic hemodialysis had elevated levels of zonulin, TNF-alpha, hs-CRP, and AAT which reflects gut permeability induced systemic inflammatory state.