Effects on protein kinase C-beta inhibition on glomerular vascular endothelial growth factor expression and endothelial cells in advanced experimental diabetic nephropathy.
Ruboxistaurin is an inhibitor of the beta isoform of protein kinase C (PKC-beta) that reduces the actions of vascular endothelial growth factor (VEGF) and attenuates the progression of diabetic retinopathy. In the glomerulus VEGF is constitutively expressed where it likely has a role in maintaining endothelial cell integrity, particularly in disease states. Given its potential use in diabetic nephropathy, we sought to determine the effects of PKC-beta inhibition on VEGF and glomerular endothelial cells in experimental diabetic nephropathy. Studies were conducted in (mRen-2)27 rat, a transgenic rodent with hypertension and an enhanced renin-angiotensin system that following induction of diabetes with streptozotocin develops many of the features of diabetic nephropathy. Moreover, to mimic the clinical context, the effects of PKC-beta inhibition were examined both with and without concomitant angiotensin-converting enzyme (ACE) inhibitor therapy. Diabetic Ren-2 rats were randomized to receive either vehicle, the ACE inhibitor, perindopril (0.2 mg/l in drinking water), ruboxistaurin (10 mg.kg(-1).day(-1), admixed in chow), or their combination and studied for 12 wk. Diabetic Ren-2 rats displayed glomerular endothelial cell loss in association with overexpression of VEGF mRNA. Both cell loss and VEGF overexpression were attenuated by the administration of either perindopril or ruboxistaurin, as single agent treatments with their combination providing additional, incremental improvements, reducing these manifestations of injury down to levels seen in nondiabetic, normotensive, nontransgenic animals. Combination therapy was also associated with additional improvements in albuminuria and glomerulosclerosis.
Kelly
Darren J
DJ
Dept. of Medicine, St. Vincent's Hospital, Fitzroy, Victoria 3065, Australia. dkelly@medstv.unimelb.edu.au
Buck
Danielle
D
Cox
Alison J
AJ
Zhang
Yuan
Y
Gilbert
Richard E
RE
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D000818:Animals; D030801:Animals, Genetically Modified; D001345:Autoradiography; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000473:pathology; D003928:Diabetic Nephropathies / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007678:Kidney Glomerulus / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D064546:Protein Kinase C beta; D051381:Rats; D012084:Renin-Angiotensin System / Q000187:drug effects / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis* / Q000235:genetics
D000806:Angiotensin-Converting Enzyme Inhibitors; D001786:Blood Glucose; D004791:Enzyme Inhibitors; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; D011493:Protein Kinase C; D064546:Protein Kinase C beta