Human Skin, Oral, and Gut Microbiomes Predict Chronological Age.

Human gut microbiomes are known to change with age, yet the relative value of human microbiomes across the body as predictors of age, and prediction robustness across populations is unknown. In this study, we tested the ability of the oral, gut, and skin (hand and forehead) microbiomes to predict age in adults using random forest regression on data combined from multiple publicly available studies, evaluating the models in each cohort individually. Intriguingly, the skin microbiome provides the best prediction of age (mean ± standard deviation, 3.8 ± 0.45 years, versus 4.5 ± 0.14 years for the oral microbiome and 11.5 ± 0.12 years for the gut microbiome). This also agrees with forensic studies showing that the skin microbiome predicts postmortem interval better than microbiomes from other body sites. Age prediction models constructed from the hand microbiome generalized to the forehead and vice versa, across cohorts, and results from the gut microbiome generalized across multiple cohorts (United States, United Kingdom, and China). Interestingly, taxa enriched in young individuals (18 to 30 years) tend to be more abundant and more prevalent than taxa enriched in elderly individuals (>60 yrs), suggesting a model in which physiological aging occurs concomitantly with the loss of key taxa over a lifetime, enabling potential microbiome-targeted therapeutic strategies to prevent aging.IMPORTANCE Considerable evidence suggests that the gut microbiome changes with age or even accelerates aging in adults. Whether the age-related changes in the gut microbiome are more or less prominent than those for other body sites and whether predictions can be made about a person's age from a microbiome sample remain unknown. We therefore combined several large studies from different countries to determine which body site's microbiome could most accurately predict age. We found that the skin was the best, on average yielding predictions within 4 years of chronological age. This study sets the stage for future research on the role of the microbiome in accelerating or decelerating the aging process and in the susceptibility for age-related diseases

Temporal Microbiome Dynamics: From Circadian Rhythms to Probiotic Evolution

Microbial life is all around us and inside us in an unseen vast and varied ecosystem. For the past several decades, the microbiome field has attempted to characterize this microscopic web of life using next generation sequencing technology. It turns out that the number of host organism cells is generally outnumbered by the number of microbial cells that live on and within them. Moreover, these microbes collectively have two orders of magnitude more genes than their host organism. While the host organism’s genome stays constant during its life, the microbial community and its associated genes change much more frequently. Since microbial lifespans are sometimes measured in minutes, selective pressures in the host micro-environments can rapidly affect the evolution and gene content of the microorganisms present. Over the course of a lifetime, the host winds up with a unique set of microbes selected to fit their unique individual environment, from immune system quirks to specialized diets to biological rhythms. However, despite biological rhythms having always played a role in host behavior and survival, the impact of time on health has been a widely neglected realm until recently. The basic argument of this thesis is that time is an underappreciated but critical variable that impacts both experimental study design as well as host health

Pre-Natal Exposure to Mouse Parvovirus at Day 5 and 12 Gestation Does Not Induce Immune Tolerance

<div><p>Parvoviruses have a predilection for rapidly dividing cells such as occurs during embryonic development. Potentially, <i>in utero</i> exposure could lead to immune tolerance in progeny mice. To determine if MPV infection <i>in utero</i> results in immune tolerance, pregnant mice were inoculated by oral gavage with 50 ID₅₀ MPV1e or sham inoculated with phosphate buffered saline at day 5 and 12 gestation. Offspring were fostered to MPV-negative recipient dams prior to development of a milk spot. After confirming the offspring were seronegative for MPV by serology and not shedding by fecal PCR, they were challenged with 50 ID₅₀ MPV1e by oral gavage at weaning or sham inoculated. At 4 weeks post inoculation, all weanlings exposed <i>in utero</i> developed antibodies to MPV, and MPV was detected by fecal PCR. Similarly, all weanlings from sham-inoculated dams challenged with MPV developed antibodies and MPV was detected by fecal PCR. None of the sham inoculated weanling mice from MPV infected dams or sham infected dams developed antibodies to MPV nor was MPV detected by fecal PCR. These results demonstrate that <i>in utero</i> exposure to MPV1e via oral gavage was insufficient to induce immune tolerance and provides greater confidence that rederivation techniques may successfully eliminate colonies of MPV. Furthermore, our findings do not provide evidence that MPV tolerance may contribute to hidden infections in mouse colonies.</p></div

PCR and serology results from weanling mice pre- and post-MPV inoculation.

<p>PCR and serology results from weanling mice pre- and post-MPV inoculation.</p

Engineering the microbiome for animal health and conservation

Impact statementConsidering the clear effects of microbiota on important aspects of animal biology and development (including in humans), this topic is timely and broadly appealing, as it compels us to consider the possibilities of altering the microbiome (without antibiotics) to positively affect animal health. In this review, we highlight three general approaches to manipulating the microbiome that have demonstrated success and promise for use in animal health. We also point out knowledge gaps where further inquiry would most benefit the field. Our paper not only provides a short and digestible overview of the current state of application, but also calls for further exploration of the microbial diversity at hand to expand our toolkit, while also leveraging the diversity and flexibility of animal systems to better understand mechanisms of efficacy

Youth Development through Veterinary Science, 7: Is Your Bird Feeling Blue?

Part 7 of the Youth Development through Veterinary Science Series, a 4H Youth Development curriculum that introduces youth to many aspects of veterinary science

Youth Development through Veterinary Science, 2: Fur, Feathers, Skin and Scales

Part 2 of the Youth Development through Veterinary Science Series, a 4H Youth Development curriculum that introduces youth to many aspects of veterinary science