Innate immunity, through late complement components activation, contributes to the development of early vascular inflammation and morphologic alterations in experimental diabetes.

OBJECTIVE: To verify if innate immunity, and namely the assembly of terminal complement complex (TCC) could be involved in the development of early diabetic vascular damage. METHODS AND RESULTS: At first in 2 groups of diabetic or non-diabetic Wistar rats the occurrence of basal or stimulated stable adherence to the endothelial layer and extravasation of circulating fluorescently-labelled leukocytes was assessed by using an in vivo videomicroscopy technique. In a second part of the study, the development of vascular damage in short term diabetes was studied in the genetically C6 deficient rats of the PVG strain, and compared with those observed in the wild-type C6 sufficient animals. Here, the analysis of mesentery vascular expression of mRNA for vascular cell adhesion molecule (VCAM)-1, transforming growth factor-ß (TGF-ß), connective tissue growth factor (CTGF), and platelet-derived growth factor (PDGF), the evaluation of intravascular protein levels of VCAM-1, TGF-ß, CTGF, proliferative cell nuclear antigen (PCNA), as well as the assessment of structural changes and Complement components deposition at the mesentery arterial vascular wall were also performed. CONCLUSIONS: Leukocyte trafficking, mesentery arteries hypertrophy, extracellular matrix deposition, local vascular gene and protein expression of VCAM-1, TGF-ß, CTGF and PCNA, as well as PGDF gene expression were all increased by short term diabetes, but all significantly reduced in the C6 deficient diabetic animals, thus suggesting an active role for TCC in the development of vascular inflammation in the early phases of experimental diabetes.

Orally administered microencapsulated lysozyme downregulates serum AGE and reduces the severity of early-stage diabetic nephropathy.

AIM: Diabetic nephropathy is the leading cause of end-stage kidney disease in developed countries and is related to chronic hyperglycaemia. The increased production and tissue deposition of advanced glycation end products (AGE) are known to play a major role in the pathogenesis of diabetic kidney damage. This study was undertaken to determine if lysozyme (LZ), microencapsulated in orally administrable chitosan-coated alginate microspheres (MS), is effective against the early changes seen in the initial stages of diabetic nephropathy. METHODS: LZ-containing MS (MSLZ) and an equivalent dose (equidose) of nonencapsulated LZ were given as oral treatments. LZ was administered to Wistar rats for seven weeks after diabetes induction with streptozotocin. RESULTS: The results showed that microencapsulated LZ treatment significantly reduced the concentration of serum AGE in the circulation and their deposition in the kidneys. Likewise, MSLZ significantly prevented the development of microalbuminuria compared with untreated diabetic rats. Furthermore, MSLZ significantly prevented the development of glomerular and renal hypertrophy as well as overexpression of AGE receptors (RAGE). An equidose of free LZ had little or no effect whatsoever. CONCLUSION: Our study supports a relationship between serum AGE and nephropathy in diabetes, and suggests that orally administered microencapsulated LZ can exert kidney-protective activity in a diabetic animal model.