Avaliação de citocinas e quimiocinas no soro e em biópsias renais de pacientes diabéticos com e sem alteração renal

Abstract

Introduction: Type 2 Diabetes Mellitus (T2DM) is the most prevalent subtype of Diabetes Mellitus, and Diabetic Nephropathy (DN) is the most common chronic microvascular complication in T2DM, considered the leading cause of end-stage renal failure in the world. Low-grade chronic inflammation has been identified as one of the triggering factors for kidney injury in T2DM patients. However, studies are still needed to evaluate the influence of the inflammatory process on the promotion of decreased renal function in T2DM patients and on the progression of DN. Thus, the aim of this study was to evaluate the serum concentrations of inflammatory mediators in T2DM patients with or without renal alteration (RA), as well as the expression of inflammatory cytokines and chemokines (IL-1β, IL-4, IL-6, IL- 8, IL-10, TNF- α, TNFR1 and Eotaxin) in renal kidney biopsies native to diabetic patients with DN, as well as the relationship of these mediators with decreased renal function. Material and methods: Serum samples from 76 patients with T2DM and 24 healthy individuals were selected. Patients with T2DM were divided into two groups according to the estimated glomerular filtration rate (eGFR): T2DM group without RA (n= 56, with eGFR> 60 mL / min / 1.73m2) and T2DM group with RA (n= 20, with eGFR <60 mL / min / 1.73m2). Serum levels of cytokines, chemokines and adipokines were evaluated by Multiplex and ELISA immunoassay. For in situ analysis, 44 native kidney biopsies from patients with DN (DN group) and 23 control cases (control group) were selected. In situ expressions of eotaxin, MIP-1α, IL-8, IL-4, IL-10, TNF- α, TNFR1, IL-1β and IL-6 were evaluated by immunohistochemistry. Results: Serum levels of TNFR1 and leptin were higher in the T2DM group with RA than in the T2DM group without RA and control group. All patients with T2DM had increased serum resistin, IL-8 and MIP-1α levels compared to the control group. Serum adiponectin levels were higher and IL-4 decreased in the T2DM group with RA compared to the control group. eGFR positively correlated with IL-4 and negatively with TNFR1, TNFR2 and leptin in patients with T2DM. In the T2DM group with RA, eGFR was negatively correlated with TNFR1 and resistin. TNFR1 was positively correlated with resistin and leptin, as well as resistin with IL-8 and leptin. In the in situ analysis, it was observed that the DN group showed increased expression of IL-6, IL-1β, IL-4 and eotaxin, and decreased expression of TNFR1 and IL-8 compared to the control group. However, the expressions of IL-10, TNF-α and MIP-1α showed no significant difference between groups. Regarding interstitial inflammation, there was an increase in IL-6 expressions in scores 0 and 1 compared to score 2, IL-10 in score 2 compared to score 0, and eotaxin in score 2 compared to scores 0 and 1, while IL-8 and MIP-1α showed no significant difference.In addition, it was observed that eotaxin tended to have a negative correlation with eGFR. Conclusions: Increased serum levels of TNFR1, adipokines, chemokines and decreased IL-4 play important role in the inflammatory process developed in T2DM and decreased renal function. In addition, we suggest that serum TNFR1 is a strong predictor of renal dysfunction in patients with T2DM. In the evaluation of in situ expression, patients with DN presented increased expression of IL-6, IL-1β, IL-4 and eotaxin. It was observed that eotaxin expression may be playing an important role in the progression of interstitial inflammation in DN, as well as being related to the decrease of eGFR in these patients.