Uncovering the relationship between the microbiome and aging

A recent study published in PLOSbiology The journal discussed recent advances in understanding how the microbiome influences aging and related diseases.

study: Train your microbiome to help us live longer and thrive. Image Credit: fizkes/Shutterstock.com

Background

Age is a major risk factor for some diseases in high-income countries. Microorganisms colonize various parts of the human body, but the greatest colonization occurs along the gastrointestinal (GI) tract. Previous studies have highlighted the important role of the gut microbiota in health and disease.

The impact of the microbiome on the aging process and the potential for manipulating the microbiome to promote healthy aging remain unknown.

In this study, the authors discussed emerging evidence on the influence/role of the microbiome in aging and age-related diseases.

aging and the microbiome

People over the age of 100 have a higher diversity and concentration of bacteria than younger people. Clostridium, Parabacteroides, and Aristipes.

In line with this, many microbial metabolites are elevated in centenarians. Vulnerability is associated with individual differences in gut microbiota. Older frail adults have less gut microbial diversity than nonfrail adults.

However, the causality of microbiota in vulnerability has not yet been established. Aging is accompanied by impairment of the immune system, leading to the proliferation of microorganisms that were previously suppressed by the immune system.

Effect of microbiome on host lifespan

Studies in germ-free (GF) animal models support a causal role for the microbiome in determining host lifespan. Studies in model systems suggest that exposure to the microbiome during childhood is beneficial in extending lifespan.

Evidence suggests bacterial colonization during embryonic development. Drosophila melanogaster Extend life.

Nevertheless, this is not the case in GF mice, rats, or caenorhabditis elegance They live longer than conventionally-raised control animals. Therefore, the detrimental effects of microbiota in later life may outweigh the potential benefits of colonization in early childhood.

The microbiome can shorten the lifespan of older animals. for example, Escherichia Escherichia coli accumulation in GI caenorhabditis elegance It can lead to age-related death.

According to a study, middle-aged (9.5 weeks) medaka treated with antibiotics lived longer than untreated medaka. Interestingly, inoculation of the microbiota from 6-week-old medaka fish extended lifespan in the middle-aged group.

In addition, studies on mouse models of progeria show the potential to extend lifespan through microbiome-based interventions.

Role of the Microbiome in Age-Related Diseases

The prevalence of cancer increases with age, from less than 25 per 100,000 in individuals under the age of 20 to over 1,000 per 100,000 in those over the age of 60. This trend is also observed in prostate, colorectal, or breast cancer.

By comparing malignant tumors of colorectal cancer with adjacent non-malignant mucosa, Fusobacterium nuclear nucleus greatly enhanced.

Studies in mice have provided evidence for a causal role for this bacterium in colon cancer, activating pathways that promote oncogenic and pro-inflammatory gene expression and myeloid cell invasion.

Additionally, fecal microbiota transplantation (FMT) from melanoma Patients who responded to immunotherapy in others led to reductions in tumor size. The microbiome may also metabolize anticancer drugs into downstream metabolites with increased/decreased activity.

Studies highlight several pathways by which the microbiome may influence type 2 diabetes or obesity phenotypes. The microbiome contributes to caloric intake by aiding the digestion of otherwise inaccessible dietary constituents.

We can also influence host energy expenditure by altering host enzymatic activity and gene expression. Most cases of Parkinson’s disease (>95%) occurred in adults older than her 50 years, providing emerging evidence that the gastrointestinal tract is involved in the disease.

Studies in mice have revealed mechanisms by which the gut microbiota and the brain communicate to influence the pathogenesis of Parkinson’s disease. Changes in the microbiota have been observed in a mouse model of Parkinson’s disease with α-synuclein overexpression (the ASO model).

Colonization of GF ASO mice with infected mouse/human gut microbiota exacerbated motor dysfunction and brain pathology.

sex, aging and the microbiome

Aging differs between men and women, with differences in lifespan, age-related diseases, and frailty. Most age-related diseases exhibit sexual dimorphism. Cancer incidence/survival is higher in women, and the incidence of some non-reproductive cancers is highly gender-biased.

In addition, women are at greater risk of obesity than men, and the risk of type 2 diabetes is similar for men and women.

Men are at higher risk of Parkinson’s disease, but women experience a more serious illness. Recent studies have shown that gender and the microbiome are linked in humans. Preliminary results indicate that sex hormones are mediators of this association.

Sex hormone levels are altered in GF mice compared to conventionally housed mice. Moreover, circulating levels of sex hormones are related to the composition and diversity of the gut microbiota.

in conclusion

The authors summarized the existing evidence for the role of the microbiome in aging and related diseases.

Future research on aging or age-related diseases should focus on the role of the microbiome using GF models, microbiome profiling and controls for relevant variables.

Furthermore, it is important to explain how gender alters the microbiome and downstream outcomes of age-related diseases. Overall, this emerging interdisciplinary research domain can address general questions about lifelong host–microbiome interactions.