Exploring the exposome: Mayo Clinic studies impact environmental exposures have on health

ROCHESTER, Minnesota — An accumulation of environmental chemicals, pollutants, microbes, and particulates may be living inside each of us — acquired from the air we breathe, the food we eat, products we touch, and the water we drink. These sometimes-harmful exposures can interact with our genes to fuel disease. Researchers at the Mayo Clinic Center for Individualized Medicine are studying lifetime environmental exposures, called the exposome, and assessing biological responses to those exposures.  

Environmental factors have been linked to diseases including cancer, heart disease, lung illnesses, autoimmune diseases, and stroke. Environmental factors are associated with more than 80% of human diseases and nearly 1 in 6 deaths worldwide, research shows.  

"We've made significant progress in mapping the human genome and understanding the role of genes in diseases, but genetics only accounts for approximately 10% to 15% of diseases. Now, the key to accelerating further discoveries in individualized medicine lies in putting the exposome under the microscope," says Konstantinos Lazaridis, M.D., the Carlson and Nelson Endowed Executive Director for Mayo Clinic's Center for Individualized Medicine. 

The exposome is considered a counterpart to the genome (a person's complete set of DNA). In many diseases, the exposome and genome work in combination, Dr. Lazaridis says. Mayo’s research will examine the impact of exposures over a lifetime and how those two elements interact to maintain wellness or create disease.  

"Think of a plant," Dr. Lazaridis adds. "The health and longevity of the plant are not necessarily determined by what the plant is made of.  It depends on the quality of the soil it is planted in, the cleanliness of the air that surrounds it, and the amount of chemicals and pesticides it's exposed to. It also depends on how those exposures interact with the plant's biological characteristics. The same is true for humans." 

Dr. Lazaridis says identifying meaningful exposome associations to disease will require large-scale data analysis, deep-learning artificial intelligence methods, and complex multi-omics investigations. Multi-omics is a combination of two or more "omics" approaches, such as genomics, mapping genomes; proteomics, the study of proteins; metabolomics, the study of metabolic processes to identify the underlying causes of disease; epigenomics, the study of epigenetic changes on DNA; and transcriptomics, the study of RNA molecules. 

"Every person has a unique environmental footprint that can be analyzed through signatures in the blood, urine, saliva, hair, etc.," Dr. Lazaridis says. "Ultimately, we hope to understand how these exposures interact with a person's genomic profile to influence their health so we can answer why one person who is exposed to a persistent pollutant develops cancer while another with the same exposure may not. And which low-level environmental exposures contribute substantially to the onset of disease?"  

Dr. Lazaridis says advancing the understanding of the exposome and how environmental exposures affect a person's health will help guide lifestyle changes, interventions and prevention. 

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