The impact of novel probiotics isolated from the human gut on the gut microbiota and health

Abstract

The gut microbiota plays a pivotal role in influencing the metabolism and immune responses of the body. A balanced microbial composition promotes metabolic health through various mechanisms, including the production of beneficial metabolites, which help regulate inflammation and support immune functions. In contrast, imbalance in the gut microbiota, known as dysbiosis, can disrupt metabolic processes and increase the risk of developing diseases, such as obesity, type 2 diabetes, and inflammatory disorders. The composition of the gut microbiota is dynamic and can be influenced by environmental factors such as diet, medication, and the consumption of live bacteria. Since the early 1900s, bacteria isolated from food and have been used as probiotics. However, the human gut also offers an enormous reservoir of bacterial strains, and recent advances in microbiota research have led to the discovery of strains with probiotic potentials. These strains, derived from a broad spectrum of microbial taxa, differ in their ecological properties and how they interact with their hosts. For most probiotics bacterial structural components and metabolites, such as short-chain fatty acids, contribute to the maintenance of metabolic and immunological homeostasis by regulating inflammation and reinforcing gut barrier integrity. Metabolites produced by probiotic strains can also be used for bacterial cross-feeding to promote a balanced microbiota. Despite the challenges related to safety, stability, and strain-specific properties, several newly identified strains offer great potential for personalized probiotic interventions, allowing for targeted health strategies.

Keywords: cardiovascular disease; dietary intervention; dyslipidaemia; fatty liver disease; mouse model.

FIGURE 1

The influence of environmental factors on the gut microbiota. Many environmental factors can affect gut ecology and function, thereby influencing host physiology and health. Breastfeeding, dietary fibres, omega‐3 fatty acids, phytosterols, probiotics, and leanness are associated with a balanced gut microbiota characterized by high diversity, resilience, and high capacity for the fermentation of fibres. This can contribute to reduced inflammation, improved metabolic regulation, and a decreased risk of developing various diseases. In contrast, Western diets, antibiotics, and obesity may have the opposite effects.

FIGURE 2

Potential probiotics derived from the gut microbiota and their effects on microbial ecology and host physiology. Probiotics can influence the gut microbiota and the host through several mechanisms. Butyrate oxidation provides energy for colonocytes and supports gut homeostasis by reducing oxygen levels. Butyrate also counteracts inflammation and carcinogenesis via GPR109A and histone deacetylase (HDAC) inhibition, while supporting gut integrity by improving tight junctions (TJs). Acetate and propionate enhance immune function and influence gut motility and appetite through activation of GPR41/43 in L‐cells, while also increasing gut motility via stimulation of the enteric nervous system (ENS). Probiotic bacteria can further reduce inflammation through other species‐ or strain‐specific mechanisms, including the production of salicylic acid metabolites, low‐inflammatory endotoxins, amino acid metabolites, polysaccharide A (PSA), and Amuc_1100. Additionally, probiotic strains can produce bile acids that regulate host metabolism and promote a balanced gut microbiota by cross‐feeding with other bacterial species.