Chemokines and macrophage migration inhibitory factor in diabetic nephropathy.

Abstract

Introduction: Diabetic nephropathy (DN) is the leading cause of end-stage renal disease in the Western world. Aim: To determine whether macrophage migration inhibitory factor (MIF), monocyte chemoattractant protein-1 (MCP-1) or CC chemokine ligand 18 (CCL18) have a causative role in the development of renal inflammation and fibrosis in DN and are useful biomarkers of disease progression. Methods: Urine and plasma samples were collected from 115 DM and 116 Non-DM at baseline, previously analysed for MCP-1 and CCL18 ELISA by Dr Qureshi. I measured MIF in these samples and collected 107 DM and 114 Non-DM data points (GFR, ACR/UPCR and clinical parameters) at >18 months and >3 years. MIF, MCP-1 and CCL18 urine, plasma and serum analysis was performed in 42 DM and 60 Non-DM at >3 years follow up. Intrinsic renal cells were cultured and stimulated with diabetic conditions. These cytokines and fibronectin were measured in tubuloepithelial cells and podocytes. Results: Baseline plasma CCL18 and MIF predicted a decline in GFR in DM at >18 months but not at >3 years. Cytokine production varies over time with significant correlations at baseline that are not maintained. Cytokines correlate differently with GFR, ACR/UPCR in DM versus Non-DM proteinuric renal diseases. Plasma and serum cytokine levels correlated significantly with no correlation between these and urinary levels. All intrinsic renal cells were able to produce MIF, MCP-1 and CCL18 following stimulation. The interaction of these cytokines and their effects on fibronectin vary in diabetic conditions and following recombinant cytokine stimulation. The diabetic environment appears to orchestrate cytokine signals according to cell type. Conclusion: These results suggest cytokines may play a key role in the pathogenesis and or progression of DN. The clinical study suggests cytokines may predict progression; however, larger studies are needed with samples taken at different time points.