Age-Related NAFLD: The Use of Probiotics as a Supportive Therapeutic Intervention

Abstract

Human aging, a natural process characterized by structural and physiological changes, leads to alterations of homeostatic mechanisms, decline of biological functions, and subsequently, the organism becomes vulnerable to external stress or damage. In fact, the elderly population is prone to develop diseases due to deterioration of physiological and biological systems. With aging, the production of reactive oxygen species (ROS) increases, and this causes lipid, protein, and DNA damage, leading to cellular dysfunction and altered cellular processes. Indeed, oxidative stress plays a key role in the pathogenesis of several chronic disorders, including hepatic diseases, such as non-alcoholic fatty liver disease (NAFLD). NAFLD, the most common liver disorder in the Western world, is characterized by intrahepatic lipid accumulation; is highly prevalent in the aging population; and is closely associated with obesity, insulin resistance, hypertension, and dyslipidemia. Among the risk factors involved in the pathogenesis of NAFLD, the dysbiotic gut microbiota plays an essential role, leading to low-grade chronic inflammation, oxidative stress, and production of various toxic metabolites. The intestinal microbiota is a dynamic ecosystem of microbes involved in the maintenance of physiological homeostasis; the alteration of its composition and function, during aging, is implicated in different liver diseases. Therefore, gut microbiota restoration might be a complementary approach for treating NAFLD. The administration of probiotics, which can relieve oxidative stress and elicit several anti-aging properties, could be a strategy to modify the composition and restore a healthy gut microbiota. Indeed, probiotics could represent a valid supplement to prevent and/or help treating some diseases, such as NAFLD, thus improving the already available pharmacological intervention. Moreover, in aging, intervention of prebiotics and fecal microbiota transplantation, as well as probiotics, will provide novel therapeutic approaches. However, the relevant research is limited, and several scientific research works need to be done in the near future to confirm their efficacy.

Selenium- and/or Zinc-Enriched Egg Diet Improves Oxidative Damage and Regulates Gut Microbiota in D-Gal-Induced Aging Mice

“…Impairment of the functional barrier of the intestinal tract will lead to the entry of certain microorganisms into the circulation, which will then reach the liver and cause liver dysfunction, further affecting aging through the liver–gut axis [ 53 ]. At the same time, dysbiosis of the intestinal flora will lead to low-grade chronic inflammation, oxidative stress, and the production of various toxic metabolites; alterations in the composition and function of the intestinal flora are also associated with different liver diseases during aging [ 54 ]. Gut microbiota can promote gut health by regulating the metabolism and transport of trace elements (Se, Zn, Mn, Fe, etc.)…”

Recent advances in age-related metabolic dysfunction-associated steatotic liver disease

“…Furthermore, modifications in GM composition result in the endogenous production of ethanol, which consequently compromises the integrity of the intestinal barrier and incites ROS accumulation in hepatic stellate cells and Kupffer cells[ 37 ]. Studies have shown that probiotics can restore homeostasis in the GM and mitigate oxidative stress[ 67 ]. Specifically, members of the Lactobacillus genus have demonstrated the ability to modulate the expression of inflammatory cytokines, including but not limited to IL-6, IL-1β, IL-1α, IL-12, and interferon-γ, both in serum and colonic tissues.…”

Recommendations for nutritional supplements for dry eye disease: current advances

“…Patients with autoimmune DED often experience damage to ocular surface tissues such as the cornea, conjunctival goblet cells, and lacrimal glands. This damage is frequently associated with alterations in gut microbial diversity and abundance (Bai et al, 2023), which can trigger systemic inflammation and contribute to a range of ocular disorders, including age-related macular degeneration, uveitis, diabetic retinopathy, and glaucoma (Bai et al, 2023;Campagnoli et al, 2023).…”