Serum renalase and Urotensin-2 levels in obese patients

Introduction and Objective: Obesity is a multifactorial, chronic disease that occurs with excessive fat storage in the body and can cause physical and mental problems. The most important risk factors in the formation of obesity are sedentary life, excessive and malnutrition habits, age, gender, education level and genetic factors. It has been shown that there is a close relationship between obesity and many diseases such as hypertension, cardiovascular disease, diabetes, end-stage renal failure. Since obesity not only affects public health seriously but also creates a serious financial burden in the treatment of complications, primary and secondary protection pathways should be carefully developed and implemented. Renalase is a monoamine oxidase that metabolizes circulating catecholamines, produced mainly by the kidneys, and has also been shown to be released from the heart, skeletal muscle, small intestine, brown and white adipose tissue. Renalaz catecholamines regulate blood pressure and sympathetic tone. The detected form of urotensin-2 (U-II) in humans is the most potent vasoconstrictor peptide shown in mammals. While U-II can act vasodilator in normal physiological conditions, it creates vasoconstriction especially in pathological conditions such as endothelial dysfunction. U-II levels have been shown to increase in correlation with the presence of hypertension, congestive heart failure, coronary artery disease, atherosclerosis, diabetes and metabolic syndrome. In this study, the relationship between obesity, known to be associated with metabolic syndrome and cardiovascular diseases, with serum renalase and U-II levels was investigated. Also, in our study, the relationship of these two parameters with leptin and ghrelin, which is a family of adipokines, was examined. With this study, it is aimed to understand the possible role of renalase and U-II levels in the development of obesity, and the relationship between these two paramaters and the comorbid conditions with increasing incidence in obesity was investigated. Material and Method: In this study, 56 patients with BMI> 30 kg / m2 and 34 normal-weight volunteers who applied to the Internal Medicine Outpatient Clinic of Düzce University Medical Faculty between February 2019 and June 2019 were included in the study within the framework of exclusion criteria. Patients; Written informed consent forms were selected from those who volunteered to participate in the research. Age, gender, educational status, additional diseases, habits, anthropometric measurements, body composition data, laboratory parameters and U-II, leptin, ghrelin and renalase levels were evaluated between the two groups. Results: A total of 90 participants were included in the study. Of the participants, 56 (62.2%) were obese, 34 (37.7%) were healthy controls. There were 43 (76%) women and 13 (24%) men in the patient group, while 24 (70%) women and 10 (30%) men were in the control group. There was no significant difference in terms of female gender ratio in both groups (p = 0.620). While the BMI of the patient group was 37,4 kg / m², the body mass index (BMI) of the control group was 20.6 kg / m² (p = 0.000). When the patient and control groups were compared, it was observed that systolic blood pressure and diastolic blood pressure were higher in the obese group compared to the control group (p = 0.000). In the patient group, serum renalase level was 162 (67.2-502) ng / ml, serum U-II level was 31.1 (20.39-432.97) pmol / L, serum ghrelin 2008 (1262.8-5961.2) pg / ml. These 3 parameters were statistically significantly lower in the obese group (p <0.05). According to BMI, there was no statistically significant difference in the levels of obesity in terms of renalase, U-II, leptin and ghrelin levels (p = 0.577, p = 0.575, p = 0.575, p = 812, respectively). In the comparison of serum leptin level between two groups, no statistically significant difference was found (p = 0.571). z; A statistically significant negative correlation was found between renalase and BMI and waist circumference/ hip circumference (Wc/Hc) ratio (r = -560; p = 0.000 and r = -302; p = 0.004 respectively). There was a negative correlation between renalase level and systolic and diastolic BP (p = 0.000). In the multivariate logistic regression analysis performed to predict obesity, it has been determined that being married to low leptin, U-II and Vitamin D (Vit D) levels and high ALT levels may predict the risk of obesity [Beta (B), ­0.131; p = 0.047 / Beta (B), ­0.015; p: 0.000 / Beta (B), ­0.069; p: 0.062 / Beta (B), 0.138; p: 0.007 / Beta (B), 2.775; p: 0.001 respectively]. Conclusion: In our study, the relationship between leptin and ghrelin, which are among the adipokines, which have an important place in the pathophysiology of obesity, and renalase and U-II levels with obesity were investigated. In obese individuals, renalase and U-II levels were found lower compared to normal weight individuals. The lower detection of renalase and U-II levels in obese is one of the questions to be answered whether it is one of the causes of obesity development or a result of obesity. In our study, the relationship between comorbid conditions (such as high blood pressure, dyslipidemia) and renalase, which are frequently accompanied by obesity, was also examined, and it was found that the level of renalase decreased in the high levels of TG, LDL and total cholesterol and in cases of high blood pressure. It is also thought that renalase, which is known to play a role in the regulation of sympathetic tone, may be one of the responsible factors in the development of HT in obese individuals. There is a need for comprehensive studies on this subject. Key words: Obesity, urotensin-2, renalase, leptin, ghrelin