Archaea from the gut microbiota of humans: Could be linked to chronic diseases?

Archaea comprise a unique domain of organisms with distinct biochemical and genetic differences from bacteria. Methane-forming archaea, methanogens, constitute the predominant group of archaea in the human gut microbiota, with Methanobrevibacter smithii being the most prevalent. However, the effect of methanogenic archaea and their methane production on chronic disease remains controversial. As perturbation of the microbiota is a feature of chronic conditions, such as cardiovascular disease, neurodegenerative diseases and chronic kidney disease, assessing the influence of archaea could provide a new clue to mitigating adverse effects associated with dysbiosis. In this review, we will discuss the putative role of archaea in the gut microbiota in humans and the possible link to chronic diseases.

The Impact of Enriched Resistant Starch Type-2 Cookies on the Gut Microbiome in Hemodialysis Patients: A Randomized Controlled Trial.

INTRODUCTION: Resistant starch type-2 (RS2) can mitigate inflammation and oxidative stress in hemodialysis (HD) patients. However, there is still a lack of knowledge on the impact of the RS2 on the gut microbiota community in these patients. Thus, this study aims to evaluate the effects of enriched RS2 cookies on the gut microbiome in HD patients. METHODS AND RESULTS: This comprises a randomized, double-blind, placebo-controlled trial of age-, sex-, and BMI-matched patients and controls. The RS2 group receives enriched RS2 cookies (16 g d-1 of Hi-Maize 260, Ingredion) for 4 weeks, while the placebo group received cookies made with manioc flour. Fecal microbiota composition is evaluated by the 16S ribosomal RNA gene. Analysis of the microbiota reveals that Pielou's evenness is significantly decreased after RS2 supplementation. Notably, it is observed that RS2 intervention upregulates significantly 8 Amplicon Sequencing Variants (ASV's), including Roseburia and Ruminococcus gauvreauii, which are short-chain fatty acids (SCFA) producers. Furthermore, it is associated with the downregulation of 11 ASVs, such as the pro-inflammatory Dialister. CONCLUSIONS: RS2 intervention for 4 weeks in HD patients effectively alters SCFA producers in the gut microbiota, suggesting that it could be a good nutritional strategy for patients with chronic kidney disease (CKD) on HD.