LAUSR

Diabetes mellitus, either preexisting or developing after kidney transplantation remains a crucial clinical problem. The aim of this study is to compare the proteome of histologically normal glomeruli from normoglycemic (NG), T2DM, and PTDM patients one year after kidney transplantation to identify novel early biomarkers detectable prior to the development of histologically visible diabetic nephropathy. We comparatively analyzed the proteome of histologically normal glomeruli from normoglycemic (NG) recipients, and recipients with pre-existing type 2 diabetes mellitus (T2DM), or post-transplant diabetes mellitus (PTDM), in protocol biopsies obtained one year after kidney transplantation. Glomerular cross-sections were microdissected in core biopsies from 8 NG, 8 PTDM and 8 T2DM kidney transplant recipients. Proteome was determined by liquid chromatography-tandem mass spectrometry. Relative differences in protein abundance and significantly dysregulated pathways were analyzed. Proteins related to immune response and inflammation, transport regulation and cell organization and communication, including the nephrin family, were more abundant in NG, as compared to the combined groups of diabetic patients. Proteins involved in cell morphogenesis and adhesion were less abundant in PTDM, as compared to T2DM. In contrast, CCT3, CCT4 and CNDP2 diabetic nephropathy markers, LDHB and tacrolimus binding protein FKBP1A were significantly overrepresented in glomeruli from PTDM, as compared to T2DM patients. These data suggest that glomerular proteome profile differentiates PTDM from NG and T2DM, and disruption of cell-cell interactions at molecular level represents an early event in PTDM development.