Increased circulating levels of irisin are associated with cardiovascular risk factors in subjects with acromegaly
Irisin, a peptide secreted from muscle and adipose tissues, is associated with insulin resistance as well as metabolic and cardiovascular diseases. Acromegaly is a rare disorder caused by overproduction of growth hormone (GH) and is associated with functional and structural differentiation of adipose and muscle tissues. Acromegalic subjects are also at risk of vascular diseases and metabolic dysfunctions. We aimed to determine the altered levels of irisin in subjects with active acromegaly and controlled acromegaly and in controls, and to ascertain whether there is an association between irisin and hormonal and cardiometabolic parameters.
We enrolled 40 subjects with active acromegaly, 30 subjects with controlled acromegaly, and 40 control subjects of matched age, gender, BMI, and occurrence of hypertension, diabetes, and metabolic syndrome distribution in the present cross-sectional study. Hormonal and metabolic parameters, carotid intima media thickness (cIMT), and epicardial fat thickness (EFT) of the subjects were evaluated. Irisin levels were measured using ELISA.
Circulating levels of irisin were significantly higher in acromegalic subjects compared to both controlled acromegalic subjects and controls. Moreover, irisin levels were elevated in controlled acromegalic subjects compared to controls. Irisin displayed a positive correlation with insulin resistance, cIMT, EFT, BMI, GH, and insulin-like growth factor (IGF-1) in acromegalic subjects. Irisin levels were independently associated with cIMT and EFT according to multiple regression analyses. There was an independent relationship between irisin and IGF-1.
Elevated irisin levels in acromegalic subjects were associated with cIMT and EFT, suggesting that irisin is a surrogate marker for cardiovascular risk in acromegalic subjects.
KeywordsAcromegaly Irisin Carotid intima media thickness Epicardial fat thickness Insulin resistance Insulin-like growth factor-1
one-way analysis of variance
body mass index
blood urea nitrogen
carotid intima media thickness
coefficient of variability
diastolic blood pressure
fasting blood glucose
epicardial fat thickness
high-density lipoprotein cholesterol
homeostasis model assessment of insulin resistance
insulin-like growth factor-1
low-density lipoprotein cholesterol
oral glucose tolerance test
systolic blood pressure
type 2 diabetes mellitus
variance inflation factor
We are grateful to Dr. Yeliz Pekçevik, who measured cIMT, to Dr. Ahmet Sayın, who measured EFT, and to Dr. Ayfer Çolak, who measured circulating apelin levels.
M.C. and M.D. participated in study design. M.C. and M.D. participated in study design, analyzed the data, wrote, reviewed and edited the manuscript. M.C. and M.D. provided serum samples and contributed to discussions of data interpretation. All authors reviewed and edited the manuscript. M.C. is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Compliance with ethical standards
The subjects gave their oral and written informed consent before their inclusion in the study. The study adhered strictly to the principles of the Declaration of Helsinki as revised in 2008.
Conflict of interest
The authors declare that they have no conflict of interest.
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