Expression of significance of serum secreted frizzled-related protein-4, lipoxygenase A4 and chemerin in patients with diabetic nephropathy

Objective To explore the expressions of serum secreted frizzled-related protein-4 (SFRP-4), lipoxin A4 and chemerin in patients with diabetic nephropathy and their correlations with oxidative stress and renal function.

Methods A total of 120 patients with type 2 diabetes admitted from February 2019 to June 2021 were retrospectively selected as observation group, and 122 healthy subjects during the same period were selected as control group. Patients in the observation group were divided into combined group (n=56) and non-combined group (n=64) according to the presence or absence of nephropathy. The levels of SFRP-4, chemerin, lipoxine A4, renal functionindicatorsurea nitrogen (BUN), uric acid (UA), oxidative stress indicatorsmalondialdehyde (MDA), superoxide dismutase (SOD)were compared among different groups.Receiver operating characteristic (ROC) curve was used to analyze the efficacy of each index in diagnosis of DN. Pearson correlation analysis was used to analyze the correlations of lipoxane A4, chemokine, SFRP-4 with renal function indexes and oxidative stress indexes.

Results The levels of SFRP-4, chemerin, MDA, BUN and UA in the observation group were higher than those in the control group, while the levels of lipoxin A4 and SOD in the observation group were lower than those in the control group (P < 0.05); the levels of SFRP-4, chemerin, MDA, BUN and UA in the combined group were higher than those in the non-combined group, while the levels of lipoxin A4 and SOD in the combined group were lower than those in the non-combined group (P < 0.05). ROC curve showed that the area under curves (AUC) of SFRP-4, lipoxin A4, chemokine, MDA, SOD, BUN, UA in diagnosing DN were 0.783, 0.753, 0.844, 0.722, 0.851, 0.760, 0.871, respectively. The results of correlation analysis showed that SFRP-4 was positively correlated with MDA, BUN, UA (r=0.612, 0.620, 0.629, P < 0.001), but showed no correlation with SOD (r=0.058, P=0.526). Lipoxin A4 was positively correlated with SOD (r=0.712, P < 0.001), negatively correlated with MDA and BUN (r=-0.316, P < 0.001; r=-0.233, P=0.010), and had no correlation with UA (r=0.119, P=0.197). Chemerin was positively correlated with MDA, BUN, UA (r=0.586, 0.688, 0.669, P < 0.001), but had no correlation with SOD (r=-0.031, P=0.739).

Conclusion The expression levels of chemerin, SFRP-4 and lipoxin A4 in DN patients are related to renal function and oxidative stress response, and can be used as new markers for the diagnosis of DN.