Why Does The Exposome Matter? Interview With Emory University Researcher

factory contaminating the environment via emissions

Public health scientists and authorities are always looking to understand better how the world around us affects human health. The exposome concept has gained traction as a research area in the past years as the comprehension of how everyday environmental exposures are correlated with disease development based on multiple studies increases. But, what is the exposome?

The exposome is understanted as every exposure you and I are subjected to from conception to death. It’s all-encompassing, including external factors like air pollution, lifestyle factors like the food you eat, and internal factors like hormones and metabolic signatures.

Environmental exposure is a minute-to-minute reality. You can stop eating donuts while binge-watching documentaries about climate change, but you cannot decide not to breathe anymore or drink water, and in many cases, invisible dangers lurk without much noise but gradually could be behind the development of threats for human life, such as chronic disease or reduced lifespan.

Deciphering the Exposome Puzzle: How Do Various Exposures Shape Our World?

Ok, now you’re convinced that exposomic research is valuable, but how exactly do environmental factors interact with humans?

Exposure science defines 3 broad categories of non-genetic exposures:

  • Internal exposures: These are reactions, non-genetic exposures originating within the body, caused by hormones, cytokines, and metabolites or processes like inflammation. 
  • Specific external exposures: If you can point to a particular source of exposure, such as air pollution, tobacco smoke, and lead, then it belongs to this category. 
  • General external exposures: are the combination of the environment in general, in a way, the reflection on the society in which an individual lives and thrives, such as the urban environment, climate, and socioeconomic status.

What is the relationship between the exposome and the genome?

As you now know, the human exposome is complex, as it’s a collection of constant environmental interactions that have the potential to cause epigenetic changes.

The human genome is the complete set of genetic information for a person’s organism. The exposome and the genome are closely related, as environmental exposures influence gene expression, meaning that the outside world changes our biology, even if we don’t know about it. 

Isolating a biological response is one of the main challenges of environmental health sciences. Researchers rely on studying environmental pollutants in specific populations to compare disease risk across peoples and places.

The results are worrisome. Air pollution, so prevalent in every major city, has the capacity to potentially alter gene expression in the lungs, predisposing to respiratory diseases. Ingesting food or water contaminated with lead, typical in modern agriculture, may cause severe biological impacts affecting DNA methylation. 

The exposome and the genome are critical factors in determining an individual’s health and susceptibility to disease, but their interaction and scientific monitoring are an ongoing challenge.

What are the challenges of exposure assessment?

city covered in smog

Environmental science is a complicated task. Why? Because the environment is in constant motion, people, too, are susceptible to multiple exposures that are difficult to assess and pinpoint with absolute certainty.

Here are some additional challenges of capturing the interaction between our bodies and the places we live.

Scarce systematic data on exposures 

Environmental exposure measurement is a relatively new field. Systematic data on exposures is not abundant, adding an extra layer of complexity around the exposome concept.

Lack of standardized methods for exposome assessment 

Standardized methods for exposome assessment don’t exist, making it difficult to compare findings or draw conclusions about the effects of exposures on health.

Multidisciplinary research is necessary

The exposome is a complex concept that requires multidisciplinary research to reach a meaningful conclusion, which causes coordination issues in conducting more extensive studies.

What are the implications of the exposome concept for epidemiological research?

image of a crystalline river in a mountain scenery

The exposome concept carries significant implications for epidemiological research. It offers a structured lens through which we can grasp the entirety of human environmental exposures. 

It’s a powerful tool for environmental epidemiology as it empowers researchers with insights for uncovering novel risk factors and underlying diseases and revealing the mechanisms linking exposures to health outcomes. 

Interview With Leading Exposome Expert

Dean P. Jones, Ph.D., is a biochemist and a professor at Emory University School of Medicine. 

He is a member of the Winship Cancer Institute, where he studies the molecular mechanisms of oxidative stress. He leads the Emory Clinical Biomarkers Laboratory, which uses advanced techniques to measure the effects of nutrition and the environment on human health and disease. He is a prolific researcher who has published papers cited over 1,000 times. He is an expert on the exposome, the totality of exposures that influence our health.

I talked to him a few weeks ago, and he agreed to an interview that I now share with you in its entirety as it’s illuminating in understanding the exposome and cancer epidemiology.

What are the global changes that could impact health and contribute to earlier onset of cancers?

The many global changes in the past half-century that could impact health and mainly contribute to the earlier onset of cancers include changes in the food chain due to hybrid food varieties and monoculture, changes in the processing, preservatives, and delivery of food which have resulted in less variety of plant-derived foods, changes in types and abundance of insecticides, herbicides, and fungicides, use and misuse of antibiotics, cumulative exposures to persistent organic pollutants like DDT, more common stresses such as those due to global warming and dehydration, widespread use of flame retardants, widespread dissemination of commercially useful but also toxic and carcinogenic metals, common exposures to plasticizers and plastic waste products, exposures to electronics and electronic wastes, and more readily vectored infectious agents due to the extent of international travel.

How do the assays developed over the past 15 years improve surveillance of diverse human exposures?

The assays developed over the past 15 years substantially improve surveillance of such diverse human exposures. High-resolution mass spectrometry with data science tools provided the capability to measure tens of thousands of chemical signals from small biological samples. Through the efforts of many investigators, these data include direct or indirect measures of most of the above possible causes of earlier onset cancers. A recent paper uses these measures in an agnostic manner to obtain “suspect chemicals” for breast cancer risk.

What do the analyses show about specific mass spectral signals linked to cancer outcomes?

The analyses show that specific mass spectral signals linked to cancer outcomes are associated with other exposures, and the communities of associated exposures are correlated with variations in endogenous metabolism that are linked to cancer outcomes. While these data will require replication and translation to model systems for mechanistic understanding, they provide an exposome detective framework to tackle the very challenging problem to identify risk factors for subsequent cancer development.

How does research focus on applying these methods more directly to early-onset cancers?

Research is now focused on applying these methods more directly to early-onset cancers. Research shows that children born in 1959-1967 had earlier onset cancer than their parents. This supports other research showing that cancers at multiple sites are now occurring at younger ages. Thus, this focuses attention on the exposome as a complement to the genome in contributing to earlier cancer onset.

How does studying the exposome during pregnancy provide valuable new information on multigenerational cancer risks?

Studying the exposome during pregnancy provides valuable new information on multigenerational cancer risks. The cohort provides information on a critical window of susceptibility for 3 generations because pregnancy impacts subsequent cancer risk in the mother (F0 generation). Samples during pregnancy provide information relevant to cancer in the children (F1 generation) who were fetuses at the time of sampling, and also potential risks in the grandchildren (F2 generation) who were developing gametes in daughters during fetal development.

Sources

  1. The exposome: from concept to utility. By Christopher Paul Wild
  2. The exposome: a new paradigm to study the impact of environment on health. By Martine Vrijheid
  3. The exposome and health: Where chemistry meets biology. By Roel Vermeulen, Emma L. Schymanski, Albert-László Barabási, Gary W. Miller.
Serg Valencia

Serg Valencia

Serg Valencia is a Longevity Ghostwriter and Master in Neuroscience empowering longevity pioneers to communicate their life-extending vision.

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