# Adipolin, Chemerin, Neprilysin and Metabolic Disorders Associated with Obesity
## 4 Discussion
### Relationships between Concentrations of Particular Adipokines and Other Factors  
Contrary to expectations, the concentrations of adipolin, neprilysin, and chemerin in the study groups were comparable. Presumably, it could be because the control group may have included individuals with the metabolically obese normal-weight (MONW) phenotype. Indirectly, this may be suggested by some results indicating the presence of metabolic disorders in this group of patients. It led to the conjecture that, due to the substantial abnormalities in adipokine secretion in obese individuals, their positive and negative effects may potentiate or cancel each other out. An attempt was made to find correlations between the concentrations of individual adipokines in the blood, and these correlations were found to exist. The decision tree method was used, through which exciting observations were made. Based on decision tree analyses conducted on the whole population, it was shown that the highest concentrations of chemerin were found in the group with high concentrations of neprilysin. It may indirectly confirm that the two adipokines have a similar mechanism of action. It was also shown that the highest concentrations of adipolin were found in the group with low levels of chemerin, which, like the available literature, suggests that these adipokines have opposing mechanisms of action. The blood concentrations of the adipokines analyzed are interrelated, potentially potentiating (in the case of molecules with similar functions) or abolishing (in the case of adipokines with opposing roles) their reciprocal effects. The determination of single adipokine concentrations may have little diagnostic value. In the future, it would be worthwhile to develop a panel of tests that includes the assessment of the concentrations of a more significant number of adipokines influential in shaping metabolic disorders. Their mutual proportions may be crucial in developing many diseases accompanying obesity, significantly affecting adipose tissue's secretory function.  
Our logistic analyses have given a special result (which confirms the positive correlations obtained in non-parametric analyses)--an increased frequency of high plasma adipolin concentrations (above the value of 1.08 ng/mL) with the age of subjects, occurring only in people with a BMI below 30 kg/m\({}^{2}\), so also with a low risk of insulin resistance and low frequency of another risk of factors included in metabolic syndrome. Such results were not observed in the obesity group (in our research, characterized by high BMI (range 31.1-51.6 kg/m\({}^{2}\)) and high waist circumference in women \(\geq\)88 cm (range 93-140 cm) and in men \(\geq\)102 cm (range 110-160 cm). Also, in the case of the entire population, we did not receive such a result, similar to the study of [PERSON] et al., where no statistically significant correlation was observed between the levels of serum adipolin and age in patients with coronary artery disease (CAD) [20]. Moreover, [PERSON] et al. found no association of this adipokine level with age in patients with CAD [22]. The papers of other authors connected with adipolin (CTRP12) concentrations lacked information about the analysis of the relationship between this adipokine level and age [4; 21; 23; 34; 57]. Only [PERSON] et al. reported that the C1q complement/TNF-related protein (CTRP1) level increased with age in a large cohort (CTRP1 belongs to the same CTRP superfamily as adipolin, the adipokine analyzed by us (CTRP12)) [19]. Reduced serum levels of adipolin (CTRP12) in type 2 diabetes, according to [PERSON] et al., are associated with renal dysfunction [34]. This problem probably also occurs(at least to some degree) in older obese people with multiple disorders associated with metabolic syndrome.