Review on the Alteration of Gut Microbiota: The Role of HIV Infection and Old Age

Human immunodeficiency virus (HIV) infection results in gut microbiota alteration and this is associated with immune activation and chronic inflammation. The gastrointestinal tract is a primary site of viral replication and thus HIV-induced loss of T-helper (Th) cells in the gut causes impairments in intestinal barriers, resulting in disruptions in intestinal immunity and precipitating into gut dysbiosis. Here, we show that late HIV diagnosis can negatively affect the immunological, virological, and clinical prognosis of the patients with its higher implication at an older age. Further, the review indicates that antiretroviral therapy affects the gut microbiota. We discussed the use of probiotics and prebiotics that have been indicated to play a promising role in reversing gut microbiota alteration in HIV patients. Though there are several studies reported with regard to such alterations in gut microbiota regarding HIV infection, there is a need to provide comprehensive updates. It is, therefore, the objective of this review to present most recently available evidence on the alteration of gut microbiota among HIV patients.

Human gut microbiota and healthy aging: Recent developments and future prospective

The human gut microbiota alters with the aging process. In the first 2-3 years of life, the gut microbiota varies extensively in composition and metabolic functions. After this period, the gut microbiota demonstrates adult-like more stable and diverse microbial species. However, at old age, deterioration of physiological functions of the human body enforces the decrement in count of beneficial species (e.g. Bifidobacteria) in the gut microbiota, which promotes various gut-related diseases (e.g. inflammatory bowel disease). Use of plant-based diets and probiotics/prebiotics may elevate the abundance of beneficial species and prevent gut-related diseases. Still, the connections between diet, microbes, and host are only partially known. To this end, genome-scale metabolic modeling can help to explore these connections as well as to expand the understanding of the metabolic capability of each species in the gut microbiota. This systems biology approach can also predict metabolic variations in the gut microbiota during ageing, and hereby help to design more effective probiotics/prebiotics.

Administration of a Multi-Strain Probiotic Product to Women in the Perinatal Period Differentially Affects the Breast Milk Cytokine Profile and May Have Beneficial Effects on Neonatal Gastrointestinal Functional Symptoms. A Randomized Clinical Trial

Background: Probiotic supplementation to women during pregnancy and lactation can modulate breast milk composition, with immune benefits being transferred to their infants. Aim: The aim of the study was to evaluate the effect of high-dose probiotic supplementation to women during late pregnancy and lactation on cytokine profile and secretory IgA (sIgA) in breast milk and thus to study if differences in breast milk composition can affect lactoferrin and sIgA levels in stool samples of newborns. The safety of maternal probiotic administration on neonatal growth pattern and gastrointestinal symptoms were also evaluated. Methods: In a double-blind, placebo-controlled, randomized trial, 66 women took either the probiotic (n = 33) or a placebo (n = 33) daily. Levels of interleukins (IL-6, IL-10 and IL-1β), transforming growth factor-β1 (TGF-β1), and sIgA in breast milk; and the level of sIgA and lactoferrin in newborn stool samples were analyzed at birth and then again at one month of life. Antropometrical evaluation and analysis of gastrointestinal events in newborns was also performed. Results: Probiotic maternal consumption had a significant impact on IL6 mean values in colostrum and on IL10 and TGF-β1 mean values in mature breast milk. Fecal sIgA mean values were higher in newborns whose mothers took the probiotic product than in the control group. Probiotic maternal supplementation seems to decrease incidence of infantile colic and regurgitation in infants. Conclusion: High-dose multi-strain probiotic administration to women during pregnancy influences breast milk cytokines pattern and sIgA production in newborns, and seems to improve gastrointestinal functional symptoms in infants.

Progress and challenges in developing metabolic footprints from diet in human gut microbial cometabolism

Homo sapiens harbor trillions of microbes, whose microbial metagenome (collective genome of a microbial community) using omic validation interrogation tools is estimated to be at least 100-fold that of human cells, which comprise 23,000 genes. This article highlights some of the current progress and open questions in nutrition-related areas of microbiome research. It also underscores the metabolic capabilities of microbial fermentation on nutritional substrates that require further mechanistic understanding and systems biology approaches of studying functional interactions between diet composition, gut microbiota, and host metabolism. Questions surrounding bacterial fermentation and degradation of dietary constituents (particularly by Firmicutes and Bacteroidetes) and deciphering how microbial encoding of enzymes and derived metabolites affect recovery of dietary energy by the host are more complex than previously thought. Moreover, it is essential to understand to what extent the intestinal microbiota is subject to dietary control and to integrate these data with functional metabolic signatures and biomarkers. Many lines of research have demonstrated the significant role of the gut microbiota in human physiology and disease. Probiotic and prebiotic products are proliferating in the market in response to consumer demand, and the science and technology around these products are progressing rapidly. With high-throughput molecular technologies driving the science, studying the bidirectional interactions of host-microbial cometabolism, epithelial cell maturation, shaping of innate immune development, normal vs. dysfunctional nutrient absorption and processing, and the complex signaling pathways involved is now possible. Substantiating the safety and mechanisms of action of probiotic/prebiotic formulations is critical. Beneficial modulation of the human microbiota by using these nutritional and biotherapeutic strategies holds considerable promise as next-generation drugs, vaccinomics, and metabolic agents and in novel food discovery.