Low folate status enhanced benzene-induced cytogenetic damage in bone marrow of mice: a relationship between dietary intake and tissue levels of folate

An integrative exploration of environmental stressors on the microbiome-gut-brain axis and immune mechanisms promoting neurological disorders

The microbiome-gut-brain axis is altered by environmental stressors such as heat, diet, and pollutants as well as microbes in the air, water, and soil. These stressors might alter the host's microbiome and symbiotic relationship by modifying the microbial composition or location. Compartmentalized mutualistic microbes promote the beneficial interactions in the host leading to circulating metabolites and hormones such as insulin and leptin that affect inter-organ functions. Inflammation and oxidative stress induced by environmental stressors may alter the composition, distribution, and activities of the microbes in the microbiomes such that the resultant metabolite and hormone changes are no longer beneficial. The microbiome-gut-brain axis and immune adverse changes that may accompany environmental stressors are reviewed for effects on innate and adaptive immune cells, which may make host immunity less responsive to pathogens and more reactive to self-antigens. Cardiovascular and fluid exchanges to organs might adversely alter organ functionality. Organs, especially the brain, need a consistent supply of nutrients and clearance of debris; disruption of these exchanges by stressors, and involvement of gut microbiome are discussed regarding neural dysfunctions with Alzheimer's disease, autistic spectrum disorders, viral infections, and autoimmune diseases. The focus of this review includes the manner in which environmental stressors may disrupt gut microbiota leading to adverse immune and hormonal influences on development of neuropathology related to hyperhomocysteinemia, inflammation, and oxidative stress, and how certain therapeutics may be beneficial. Strategies are explored to lessen detrimental effects of environmental stressors on central and peripheral health navigated toward (1) understanding neurological disorders and (2) promoting environmental and public health and well-being.

Aspartame, as an artificial sweetener, does not affect renal function and antioxidative states in mice

BACKGROUND AND OBJECTIVE

Aspartame (L-aspartyl L-phenylalanine methyl ester) is an artificial sweetener widely used as a sugar substitute. There are concerns regarding the effects of high aspartame doses on the kidney owing to oxidative stress; however, whether the maximum allowed dose of aspartame in humans affects the kidneys remains unknown. Therefore, in this study, we investigated whether the maximum allowed dose of aspartame in humans affects the kidneys.

METHODS

In this study, animals were fed a folate-deficient diet to mimic human aspartame metabolism. Eight-week-old ICR mice were divided into control (CTL), 40 mg/kg/day of aspartame-administered (ASP), folate-deficient diet (FD), and 40 mg/kg/day of aspartame-administered with a folate-deficient diet (FD + ASP) groups. Aspartame was administered orally for eight weeks. Thereafter, we evaluated aspartame's effect on kidneys via histological analysis.

RESULTS

There were no differences in serum creatinine and blood urea nitrogen levels between the CTL and ASP groups or between the FD and FD + ASP groups. There was no histological change in the kidneys in any group. The expression of superoxide dismutase and 4-hydroxy-2-nonenal in the kidney did not differ between the CTL and ASP groups or the FD and FD + ASP groups.

CONCLUSION

Our findings indicate that the allowed doses of aspartame in humans may not affect kidney function or oxidative states.

Glycine/glycine N-methyltransferase/sarcosine axis mediates benzene-induced hematotoxicity

Benzene, an important and widely used industrial chemical, is the cause of different types of blood disorders. However, the mechanisms of benzene-induced hematotoxicity are still unclear. This study aimed to explore the effects of benzene on metabolism, especially in amino acid metabolism, in human peripheral blood B lymphocyte cells (AHH-1 cells) treated with 1,4-benzoquinone (1,4-BQ) and in benzene-exposed population based on the un-targeted and targeted metabolomics platforms. The results showed that 1,4-BQ disturbed the metabolic activity, such as arginine biosynthesis, citrate cycle, glycine, serine, and threonine metabolism pathways, and significantly upregulated the ratio of sarcosine/glycine in vitro. Meanwhile, the targeted metabolomics further showed that the ratio of sarcosine/glycine was also increased in the benzene exposure population. Notably, the expression of glycine N-methyltransferase (GNMT), an enzyme catalyzing the transformation of glycine to sarcosine, was upregulated both in 1,4-BQ treated AHH-1 cells and benzene-exposed workers. These results imply that the glycine/GNMT/sarcosine axis was involved in benzene-induced hematotoxicity. Such evidence will help to develop a better understanding of the underlying mechanism of benzene-induced hematotoxicity at the level of amino acid metabolism.