Influence of protein kinase C (PKC) on the prognosis of diabetic nephropathy patients

Abstract

Aims: To investigate the association between protein kinase C (PKC) and the prognosis of patients with diabetic nephropathy (DN).

Methods: 92 patients with DN who had received treatments with angiotensin converting enzyme inhibitor (ACEI) or angiotensin-receptor blockade (ARB) were collected. The clinicopathologic characteristics were recorded and a 4-year follow-up with the final result of impaired renal functions (eGFR < 40 mL/min) was conducted. The expression of PKC was detected by immunohistochemical assay. Kaplan-Meier and Cox regression analysis were performed to estimate the effects of PKC on DN prognosis.

Results: According to immunohistochemical analysis, there were 54 cases with positive expression of PKC (positive rate 58.7%). Meanwhile, during the follow-up, the urine protein, mean serum creatinine and eGFR in patients with positive PKC were all higher than those in negative expression group (P < 0.05). The expression of PKC was influenced by age (P < 0.001), course of disease (P < 0.001), blood pressure (P = 0.002), blood glucose (P < 0.001), HbA1c (P = 0.002), renal functions of patients before (P = 0.011) and after (P = 0.041) the biopsy. Besides, the Kaplan-Meier curve revealed that patients with positive PKC expression had shorter survival time than those with negative PKC expression (P < 0.001). Cox regression analysis indicated that HbA1c (P = 0.009), renal functions of patients after the biopsy (P = 0.002) and PKC (P = 0.028) were important factors in the prognosis of DN and they might be independent prognostic markers.

Conclusion: The expression of PKC is relatively higher in DN patients than in healthy controls. And PKC may be a valuable prognostic marker for patients with DN.

Keywords: PKC; diabetic nephropathy; prognosis.

Figure 1

Immunohistochemical staining of PKC protein in tissue samples. The expression level of PKC was higher in DN patients. The original magnification was ×400. A. Showed negative expression of PKC in healthy controls; B. Showed positive expression of PKC in DN patients.

Figure 2

Kaplan-Meier survival analysis in patients with DN. The result indicated that patients with positive PKC expression lived shorter than those with negative PKC expression (P < 0.001).