Expression and clinical value of gastrin‐releasing peptide precursor in nephropathy and chronic kidney disease

AIM: To explore whether serum pro-gastric releasing peptide (proGRP) is elevated in nephropathy patients and evaluate the diagnostic value of proGRP in chronic kidney disease (CKD) patients. METHODS: A total of 498 nephropathy patients and 170 healthy were selected in Zhongshan Hospital, Medical College of Xiamen University, from February 2016 to September 2017. The clinical data of the different groups including serum proGRP, CKD grading, and other serum and urine renal function biomarkers were analyzed by group comparison, correlation analysis and receiver operating characteristic curve. RESULTS: Serum proGRP levels were significantly higher in the acute kidney injury and CKD groups compared with the other groups of kidney disease patients (P < 0.01), and increased with CKD grading (P < 0.01). Serum proGRP was substantially correlated with serum creatinine (r = 0.637, P < 0.01) and cystain C (0.837, P < 0.01). Serum proGRP had moderate correlations with urine beta2-macroglobulin (beta2-m; r = 0.587, P < 0.01) and alpha1-macroglobulin (alpha1-m; r = 0.557, P < 0.01). There were fair associations of serum proGRP with albumin (r = 0.10, P = 0.067), 24 h proteinuria (24 h-TPU; r = 0.092, P = 0.099), urinary albumin/urocreatinine (uAlb/Cr; r = 0.29, P < 0.01) and urinary N-acetyl-beta-D-glucosidase (r = -0.142, P < 0.01). The sensitivity of proGRP was superior to that of simplified modification of diet in renal disease (MDRD) formula in diagnosing CKD I + II (81.25% vs 66.67%), CKD III (86.42% vs 74.36%) and CKD IV (71.19% vs 69.64%), while its specificity was inferior to that of simplified MDRD formula in diagnosing CKD I + II (37.65% vs 66.97%), CKD III (56.25% vs 86.67%) and CKD IV (75.31% vs 88.46%). CONCLUSION: Serum proGRP is elevated in acute renal injury and CKD patients and increases with CKD grading. Serum proGRP is mainly affected by glomerular filtration rate and could be used for CKD staging, although the overall diagnostic sufficiency is inferior to simplified MDRD formula.