The relationship between leptin, miRNA221 and the coronar yartery disease and the severity of the disease

Coronary artery disease (CAD) has probably the most critical and most widespread type of cardiovascular disease (CVD) threatening people's health, worldwidely. High leptin levels in obese individuals participate to low-graded systemic inflammation, which makes this patients more sensitive for CVDs. The soluble leptin receptor (sOB-R) is the primary protein for leptin binding, so it is able to pivotally modifying its bioavailability. The degree of leptin's decrease may be a gauge for remaining leptin sensitivity. The status of leptin resistance and action has a biomarker called the free leptin index (FLI) and it is one of a fraction of total leptin and the sOB-R concentrations. In cardiovascular biology, micro ribonucleic acids (miRNAs) regulate many diverse processes including the maintenance of cardiac function and development of the heart. Also miRNAs are found in relationship with pathological processes and begun to be used as biomarker in some diseases. Within the scope of the study, it was aimed to search the relationship between leptin, sOB-R, FLI and miRNA221 and the CAD and the severity of the CAD. The prospective case-control study consisted of 78 individuals who had an indication for coronary angiography except acute coronary syndrome. 40 patients whose coronary lesion needed invasive treatment and 38 individuals who had normal coronary artery as the control group. The peripheral blood samples were drawn from patients and control group after performing coronary angiography. Coronary angiograms also were evaluated by quantification of the lesions according to the SYNTAX score. sOB-R and leptin levels in serum samples were determined by an enzyme immunoassay method, a two-site sandwich Enzyme Linked Immunosorbent Assay (ELISA) to quantitate sOB-R and leptin in samples. miRNA-221 expression levels determined by realtime polymerase chain reaction (PCR). The analysis of Receiver operating characteristic (ROC) curve was performed to determine the diagnostic capability of miRNA-221. We evaluated a total of 40 patients that 23 were male (57,5%) and 17 were female (42,5%). Control group included 38 individuals and 17 were male (44,7%) and 21 were female (55,3%). The results indicate that sOB-R levels were statistically higher (p<0,001*) and FLI results were significantly lower (p<0,001*) in patients than the control group. In addition, leptin level differences were not found significant between groups. As a result of the subgroup analyzes performed, the relationship between CAD and sOB-R levels and also with FLI results were independent from obesity. Also we found a significant positive correlation between l sOB-R and SYNTAX score (p<0,001*) and significant negative correlation between FLI and SYNTAX score (p<0,001*). Beside these findings miRNA-221 levels was found significantly three-folds higher in the patient group than the controls (P= 0,024). Furthermore, there was a statistically significant correlation between miRNA-221 and sOB-R (p=0,029) but no correlation with leptin, FLI and SYNTAX score. In conclusion, the results showed that sOB-R level is statistically higher and FLI is statistically lower in CAD group than the normal coronary artery group. miRNA-221 levels statistically higher in CAD group than the normal coronary artery group. Also sOB-R levels and FLI are correlated with the severity of CAD. Further, if these results are confirmed in other studies, sOB-R levels, FLI and miRNA-221 may be useful to detect significant CAD before performing coronary angiography. Key words: miRNA221, Leptin, Soluble Leptin Receptor, Coronary Artery Disease