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Obesity accelerated aging in liver tissue

New study data show that obesity is strongly correlated with an advanced epigenetic age of liver tissue.

“This is the first study that evaluated the effect of body weight on the biological ages of a variety of human tissues,” Steve Horvath, PhD, ScD, professor of human genetics at David Geffen School of Medicine at the University of California, Los Angeles, said in a press release. “Given the obesity epidemic in the Western world, the results of this study are highly relevant for public health.”

Steve Horvath

Horvath and colleagues examined 1,190 human tissue samples, including 137 liver samples, 274 blood samples, 692 adipose tissue samples and 98 muscle samples, to determine the relationship between epigenetic age acceleration and body weight. The researchers used an epigenetic clock to measure the biological age of the tissues and created methylation datasets to examine any relationship between epigenetic age acceleration and transcriptive changes.

The clock indicated that obesity did not affect the epigenetic age of fat, muscle or blood tissue, but the epigenetic age of the liver increased by 3.3 years for every 10 BMI units. An acceleration of BMI was only observed in the liver samples (P=.00068). The acceleration in the age of liver was not associated with nonalcoholic fatty liver disease score or any other traits after adjusting for BMI.

Patients in the study who underwent bariatric surgery (n=21) showed signs of decreased BMI after weight loss; however, they did not see a decrease in the age of the liver tissue during a 9-month period.

The acceleration in liver age could play a role in liver-related medical conditions, such as liver cancer and insulin resistance, according to the researchers.

“The increased epigenetic age of liver tissue in obese individuals should provide insights into common liver-related comorbidities of obesity, such as insulin resistance and liver cancer,” the researchers wrote. “These findings support the hypothesis that obesity is associated with accelerated aging effects and stresses once more the importance of maintaining a healthy weight.”

Disclosure: The researchers report no relevant financial disclosures.