Sluggish Metabolism in Adipose Tissue Linked to Health Consequences of Obesity
The Impact of Obesity on Metabolism and Health
In the quest to understand the effects of obesity on our bodies, a study delves into the correlation between excess weight and gene expression in fat and muscle tissue.
The findings suggest a weakness in energy metabolism and a higher level of inflammation in both fat and muscle tissue in individuals with obesity. Interestingly, the adverse health effects of obesity seem to be primarily linked to alterations in fat tissue rather than muscle tissue.
Obesity poses a significant threat to a person's health and well-being. It is known to substantially raise the risk of numerous diseases, including type 2 diabetes, cardiovascular disease, and certain types of cancer. Despite the well-known health risks, the rate of obesity has been steadily increasing globally.
A study revealed that between 1980 and 2015, the prevalence of obesity doubled in over 70 countries and kept climbing in most others. According to the World Health Organization (WHO), in 2016, adults had obesity, and overweight and obesity now claim the lives of more than people each year.
One of the major difficulties researchers face is distinguishing the effects of genetics from those of lifestyle on the progression of obesity and its impact on health. A team of researchers, led by two from the Obesity Research Unit at the University of Helsinki, Finland, devised an innovative method to address this.
They studied 49 pairs of identical twins who had different body mass index (BMI) readings. By doing so, they eliminated the influence of genes from the equation, as identical twins share the same genetic makeup.
The researchers then took blood samples and biopsies of fat and muscle tissue from the volunteers. They utilized various molecular techniques to analyze protein production, metabolite processing, and energy metabolism in the two types of tissue.
A significant discovery was that the activity of mitochondria, the powerhouses of cells, was diminished in both fat and muscle tissue of individuals with obesity. This change was more pronounced in fat tissue. Furthermore, there was an increase in inflammation in the tissues from twins with obesity compared to their leaner siblings.
What is worth noting is that the changes in fat tissue, but not muscle tissue, were associated with adverse health effects, such as fatty liver disease and insulin resistance, conditions that are known to contribute to the development of diabetes.
"If we were to liken mitochondria to the engine of a car, you could say that the engine's power output decreases as weight increases," explains senior author Prof. Kirsi Pietiläinen, also of the university's Obesity Research Unit.
The researchers theorize that these underperforming mitochondria may generate more reactive oxygen species, or free radicals, which fuel inflammation. "A low-powered mitochondrial engine may also produce toxic exhaust fumes, which can cause a pro-inflammatory state in adipose tissue and, consequently, the onset of diseases associated with obesity," explains Prof. Pietiläinen.
While the study identified associations between obesity and various metabolic and health measures, it could not prove the existence of any causal relationships. The study's major limitation was its cross-sectional design, which concentrated on a single point in time.
According to the enrichment data, obesity leads to specific metabolic and inflammatory changes in adipose tissue that significantly impact health conditions like diabetes. The changes include disrupted lipid metabolism, alterations in adipogenesis, and adipose tissue phenotype alterations, which contribute to chronic inflammation.
The chronic inflammation in turn leads to insulin resistance, a precursor to type 2 diabetes, by causing cells to become less responsive to insulin. This resistance, in conjunction with the metabolic and inflammatory dysregulation in obesity, creates an environment favorable to the development of type 2 diabetes.
- The study on obesity reveals a correlation between excess weight and gene expression in both fat and muscle tissue, suggesting weakness in energy metabolism and higher inflammation in fat tissue.
- Obesity is associated with a significant risk of chronic diseases like type 2 diabetes, cardiovascular disease, and certain types of cancer, despite being well-known for its health risks.
- In an attempt to distinguish the effects of lifestyle from genetics on obesity and its impact on health, a study on identical twins with different body mass indexes was conducted to evaluate protein production, metabolite processing, and energy metabolism in fat and muscle tissue.
- The research identifies specific metabolic and inflammatory changes in adipose tissue linked to obesity, contributing to chronic inflammation and insulin resistance, which are precursors to type 2 diabetes.
