Epigenetics and the Exposome: How Environment and Genes Shape Human Health

Epigenetics plays a crucial role in the relationship between genetics and the environment. Environmental factors can modulate gene expression through epigenetic mechanisms, a key phenomenon in understanding chronic diseases and well-being.

Two fundamental concepts explain this interaction: the exposome, which encompasses all environmental exposures throughout life, and epigenetics, which studies how these factors can modify gene expression without altering the DNA sequence. Understanding this relationship is essential for developing prevention strategies and personalised treatments.

How does the Exposome Influence Health?

The exposome includes all external factors that impact on our organism, from infancy to old age. Some examples are:

Air pollution: Increases the risk of respiratory and cardiovascular diseases.
Inadequate diet: Contributes to obesity and metabolic disorders.
Chronic stress: Linked to immune dysfunction and neurodegenerative diseases.

Although these factors affect everyone, their impact varies according to individual genetic predisposition. This explains why two people exposed to the same conditions may develop different biological responses.

Epigenetics: How the Environment Modifies Gene Expression

Epigenetics regulates gene activity without modifying the DNA sequence by:

DNA methylation: adds chemical groups that can activate or silence genes.
Histone modifications: affect the organisation of DNA, modulating its expression.
MicroRNAs: regulate the production of essential proteins.

A clear example is smoking: smoking not only damages the lungs, but also induces epigenetic changes that increase the risk of cardiovascular disease and cancer. The good news is that some of these changes can be reversed by eliminating harmful exposure.

The Interaction between Genes and Environment

The impact of the exposome varies according to the genetic profile of each individual. Examples of interactions include:

Pesticides and Parkinson’s disease: Certain genetic variants increase susceptibility to neurotoxins.
Smoking and lung disease: Specific mutations can increase the risk of respiratory pathologies in smokers.

Analysis of these interactions allows us to identify individuals at increased risk and develop personalised preventive strategies.

Epigenetic Markers: Keys to Future Medicine

Advances in epigenetics have led to the identification of biomarkers that facilitate the early detection of diseases and the design of personalised therapies. These markers can:

Assess biological ageing before visible signs appear.
Detect past environmental exposures, even after years.
Guide personalised treatments by restoring altered epigenetic patterns.

Epigenetics and its Impact on Public Health

The study of the exposome and epigenetics is transforming public health, promoting more precise prevention strategies. Some initiatives include:

Reduction of toxic exposures, such as pollution and tobacco.
Early diagnosis, using epigenetic biomarkers.
Stricter regulations on chemicals with health impacts.
These measures can improve quality of life and reduce the incidence of chronic diseases.

Genes and Environment: A Dynamic Link

The interaction between genetics and environment is revolutionising modern medicine. Epigenetics shows that many biological changes are reversible and that a healthy lifestyle can optimise gene expression, reducing the risk of disease.
In the era of personalised medicine, prevention and treatment must be based on each person’s unique interaction with their environment. Genetics influences our health, but the environment has significant power to shape our well-being throughout life.

Fuente: February 17, 2023 by Emily Drzymalla, Danielle Rasooly, and Muin J. Khoury, Office of Genomics and Precision Public Health, Centers for Disease Control and Prevention, Atlanta, Georgia https://blogs.cdc.gov/genomics/2023/02/17/interplay-between-the-exposome/

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