Clinical Trial Summary
There are two types of adipose tissue in humans, white and brown adipose tissue. While the
main task of white adipose tissue is energy storage, the main task of brown adipose tissue is
energy expenditure. It was previously thought that only infants have brown adipose tissue,
however today it is known that metabolically active brown adipose tissue exists in adult
humans as well. Brown adipose tissue contributes to metabolic health through both energy
expenditure and the cytokines they secrete.
Although obesity is frequently associated with many metabolic dysfunctions and
cardiometabolic diseases such as insulin resistance, prediabetes, atherogenic dyslipidemia,
metabolic syndrome, some obese individuals have been defined as metabolically healthy obese.
The mechanisms underlying the formation of the metabolic healthy obese phenotype are not well
understood. In experimental animal studies, it has been suggested that the molecular
phenotype of adipose tissue is an important factor affecting metabolic health in obese
individuals. One of the most important factors affecting the molecular phenotype of adipose
tissue is the browning potential of adipose tissue. Based on this hypothesis, in this study
it is aimed to investigate whether the browning of white adipose tissue has an effect on
determining the metabolic phenotype of metabolically healthy and unhealthy obese individuals
with the same amount of adipose tissue.
It is known that irisin, FGF21 and NRG4 are hormones that have the ability to brown the white
adipose tissue. In our study, it was aimed to investigate whether there is a difference in
serum FGF21, irisin and Neuregulin4 (NRG4) levels, which have brown adipose tissue browning
potential, in metabolically healthy and unhealthy obese. In this way, it will be found out
whether serum FGF21, irisin and NRG4 hormones, which have a browning effect on white adipose
tissue, have an effect on the metabolic health of obese individuals and whether these
hormones can be a treatment target.
In this project, participants who have BMI ≥30 kg/m2 and no criteria other than metabolic
syndrome criteria, except increased waist circumference (blood pressure ≥130/85 mmHg, fasting
blood glucose ≥100 mg/dl, triglyceride ≥150 mg/dl, HDL <40mg/dl in men, <50 mg/dl in women)
and those without prediabetes will be defined as metabolically healthy obese, on the other
hand other obese individuals will be defined as metabolic unhealthy. 10 ml blood samples will
be taken from at least 60 metabolically healthy and 60 metabolically unhealthy participants.
Serum FGF21, irisin and NRG4 levels will be measured and their levels in metabolically
healthy and unhealthy obese individuals will be compared.
