Objective The role of receptors for endogenous metabolic danger signals-associated molecular patterns (DAMPs) has been characterized recently as bridging innate immune sensory systems for DAMPs to initiation of inflammation in bone marrow-derived cells such as macrophages. However, it remains unknown whether endothelial cells (ECs), the cell type with the largest numbers and the first vessel cell type exposed to circulating DAMPs in the blood, can sense hyperlipidemia. This report determined whether caspase-1 plays a role in ECs in sensing hyperlipidemia and promoting EC activation. Approach and Results Using biochemical, immunological, pathological and bone marrow transplantation methods together with the generation of new apoplipoprotein E (ApoE)−/−/caspase-1−/− double knock-out mice we made the following observations: 1) early hyperlipidemia induced caspase-1 activation in ApoE−/− mouse aorta; 2) caspase-1−/−/ApoE−/− mice attenuated early atherosclerosis; 3) caspase-1−/−/ApoE−/− mice had decreased aortic expression of pro-inflammatory cytokines and attenuated aortic monocyte recruitment; and 4) caspase-1−/−/ApoE−/− mice had decreased EC activation including reduced adhesion molecule expression and cytokine secretion. Mechanistically, oxidized lipids activated caspase-1 and promoted pyroptosis in ECs by a ROS mechanism. Caspase-1 inhibition resulted in accumulation of sirtuin 1 (Sirt1) in the ApoE−/− aorta, and Sirt1 inhibited caspase-1 upregulated genes via activator protein-1 (AP-1) pathway. Conclusions Our results demonstrate for the first time that early hyperlipidemia promotes EC activation before monocyte recruitment via a caspase-1-Sirt1-AP-1 pathway, which provides an important insight into the development of novel therapeutics for blocking caspase-1 activation as early intervention of metabolic cardiovascular diseases and inflammations.

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OBJECTIVE -We examined whether proteomic technologies identify novel urine proteins associated with subsequent development of diabetic nephropathy in subjects with type 2 diabetes before evidence of microalbuminuria. RESEACH DESIGN AND METHODS-In a nested case-control study of Pima Indians with type 2 diabetes, baseline (serum creatinine Ͻ1.2 mg/dl and urine albumin excretion Ͻ30 mg/g) and 10-year urine samples were examined. Case subjects (n ϭ 31) developed diabetic nephropathy (urinary albumin-to-creatinine ratio Ͼ300 mg/g) over 10 years. Control subjects (n ϭ 31) were matched to case subjects (1:1) according to diabetes duration, age, sex, and BMI but remained normoalbuminuric (albumin-to-creatinine ratio Ͻ30 mg/g) over the same 10 years. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) was performed on baseline urine samples, and training (14 cases:14 controls) and validation (17:17) sets were tested.RESULTS -At baseline, A1C levels differed between case and control subjects. SELDI-TOF MS detected 714 unique urine protein peaks. Of these, a 12-peak proteomic signature correctly predicted 89% of cases of diabetic nepropathy (93% sensitivity, 86% specificity) in the training set. Applying this same signature to the independent validation set yielded an accuracy rate of 74% (71% sensitivity, 76% specificity). In multivariate analyses, the 12-peak signature was independently associated with subsequent diabetic nephropathy when applied to the validation set (odds ratio [OR] 7.9 [95% CI 1.5-43.5], P ϭ 0.017) and the entire dataset (14.5 [3.7-55.6], P ϭ 0.001), and A1C levels were no longer significant. CONCLUSIONS -Urine proteomic profiling identifies normoalbuminuric subjects with type 2 diabetes who subsequently develop diabetic nephropathy. Further studies are needed to characterize the specific proteins involved in this early prediction. Diabetes Care 30:638 -643, 2007D iabetic nephropathy from type 2 diabetes is the most common cause of end-stage renal disease in the U.S.(1); however, less than half of all subjects with type 2 diabetes develop diabetic nephropathy. Traditionally, incipient nephropathy is defined by the appearance of microalbuminuria (urine albumin excretion 30 -300 mg/24 h), which can progress to macroalbuminuria (Ͼ300 mg/24 h) and subsequently to kidney failure (2). The presence of microalbuminuria, however, does not correlate well with underlying glomerular damage, since diabetic subjects with microalbuminuria display tremendous heterogeneity when concomitant biopsies are examined (3-8). Furthermore, in type 2 diabetic subjects, the presence of microalbuminuria is often a better predictor of cardiovascular disease than of diabetic nephropathy (9).Glomerular and tubular damage resulting from type 2 diabetes occurs over several years, and it is possible that the excretions of glomerular and tubular proteins antedate the development of macroalbuminuria and perhaps even the development of microalbuminuria. The advent of novel, highly sensitive technol...

Vascular access dysfunction associated with arteriovenous grafts and fistulas contributes to the morbidity and mortality of chronic kidney disease (CKD) patients receiving hemodialysis. We hypothesized that the uremic conditions associated with CKD promote a pathophysiological vascular smooth muscle cell (VSMC) phenotype that contributes to neointimal hyperplasia. We analyzed the effect of culturing human VSMC with uremic serum. Expression of VSMC contractile marker genes was reduced 50-80% in cells exposed to uremic serum and the decreased expression was accompanied by changes in histone marks. There was an increase in proliferation in cells exposed to uremic conditions, with no change in the levels of apoptosis. Interestingly, we found that uremic serum inhibited PDGF-induced migration of VSMC. Histomorphometric analysis revealed venous neointimal hyperplasia in veins from chronic kidney disease (CKD) patients prior to any surgical manipulation as compared to veins from patients with no kidney disease. We conclude that uremia associated with CKD alters VSMC phenotype in vitro and contributes to neointimal hyperplasia formation in vivo contributing to the pathogenesis of vascular access dysfunction in CKD patients.