Connective tissue growth factor (CTGF) is one of the candidate factors mediating downstream events of transforming growth factor-β (TGF-β), but its role in fibrogenic properties of TGF-β and in tubulointerstitial fibrosis has not yet been clarified. Using unilateral ureteral obstruction (UUO) in rats, we analyzed gene expression of TGF-β1, CTGF, and fibronectin. We further investigated the effect of blockade of endogenous CTGF on TGF-β-induced fibronectin expression in cultured rat renal fibroblasts by antisense oligodeoxynucleotide (ODN) treatment. After UUO, CTGF mRNA expression in the obstructed kidney was significantly upregulated subsequent to TGF-β1, followed by marked induction of fibronectin mRNA. By in situ hybridization, CTGF mRNA was detected mainly in the interstitial fibrotic areas and tubular epithelial cells as well as in parietal glomerular epithelial cells in the obstructed kidney. The interstitial cells expressing CTGF mRNA were also positive for α-smooth muscle actin. CTGF antisense ODN transfected into cultured renal fibroblasts significantly attenuated TGF-β-stimulated upregulation of fibronectin mRNA and protein compared with control ODN transfection, together with inhibited synthesis of type I collagen. With the use of a reporter assay, rat fibronectin promoter activity was increased by 2.5-fold with stimulation by TGF-β1, and this increase was abolished with antisense CTGF treatment. Thus CTGF plays a crucial role in fibronectin synthesis induced by TGF-β, suggesting that CTGF blockade could be a possible therapeutic target against tubulointerstitial fibrosis.
Aim:The effects of exercise intervention and to assess its long-term efficacy in preventing subsequent cardiovascular events in patients with type 2 diabetes were little known on randomized controlled trial. Methods: Thirty-eight type 2 diabetic patients (21 men and 17 women) were assigned to either the exercise group (n 21) or the control group without exercise training (n 17) by simple randomization. The exercise training group was scheduled for aerobic and resistance exercise programs for 3 months. After the 3-month, we investigated endothelial function, insulin resistance, adipocytokines and inflammatory markers. The endothelial function was evaluated by examining a flow-mediated endothelium-dependent vasodilatation (FMD). Furthermore, we followed the incidence of cardiovascular events for 24 months. Results: After 3-month, HbA1C was decreased significantly in both groups. FMD was increased from 7.3 4.7% to 10.9 6.2% only in the exercise group ( p 0.05). Long-term follow-up data showed that the control group developed cardiovascular events more frequently than did the exercise group ( p 0.05). Conclusions: Exercise improves endothelial dysfunction independently of glycemic control and insulin sensitivity in patients with type 2 diabetes. The beneficial effects of 3-month exercise to reduce cardiovascular events persist for 24 months. J Atheroscler Thromb, 2010; 17:828-833.
Abstract. Local production of prostaglandins (PGs) in the kidney is increased in clinical and experimental diabetic nephropathy, but the role of PGs in the pathogenesis and progression of diabetic nephropathy has remained unclear. It is here shown that an orally active antagonist selective for the PGE receptor EP1 subtype potently prevents the progression of nephropathy in streptozotocin-induced diabetic rats. The effects are shown by ameliorated renal and glomerular hypertrophy, decreased mesangial expansion, inhibited transcriptional activation of transforming growth factor- (TGF-) and fibronectin, and complete suppression of proteinuria. In vitro, this agent completely inhibits TGF- and fibronectin upregulation in mesangial cells cultured under high-glucose conditions. These data indicate that the PGE2-EP1 system plays a crucial role in the development of diabetic renal injury in rats. It is further shown that both the EP1 antagonist and aspirin, a nonselective PG synthase inhibitor, markedly attenuate mesangial expansion, whereas only the EP1 antagonist inhibits glomerular hypertrophy and proteinuria, which suggests that these changes are caused by different mechanisms. This study reveals a potential usefulness of selective EP1 blockade as a novel therapeutic strategy for diabetic nephropathy and also brings a new insight into our understanding of this disease.
Background and Purpose-Chronic kidney disease (CKD) is increasingly recognized as an independent risk factor for stroke and myocardial infarction (MI). Few studies, however, have examined the relationship between blood pressure (BP) category and these diseases in subjects with and without CKD. Methods-We studied 5494 Japanese individuals (ages 30 to 79, without stroke or MI at baseline) who completed a baseline survey and received follow-up through December 2005. The glomerular filtration rate (GFR) was estimated using the Modification of Diet in Renal Disease study equation modified by the Japanese coefficient. CKD was defined as an estimated GFR Ͻ60 mL/min/1.73m
Evidence has emerged that undernutrition in utero is a risk factor for cardiovascular disorders in adulthood, along with genetic and environmental factors. Recently, the local expression of angiotensinogen and related bioactive substances has been demonstrated to play a pivotal role in cardiac remodeling, i.e. fibrosis and hypertrophy. The aim of the present study was to clarify the possible involvement of the local cardiac angiotensin system in fetal undernutrition-induced cardiovascular disorders. We developed a mouse model of undernutrition in utero by maternal food restriction, in which offspring (UN offspring) showed an increase in systolic blood pressure (8 wk of age, P < 0.05; and 16 wk, P < 0.01), perivascular fibrosis of the coronary artery (16 wk, P < 0.05) and cardiac cardiomegaly (16 wk, P < 0.01), and cardiomyocyte enlargement, concomitant with a significant augmentation of angiotensinogen (P < 0.05) and endothelin-1 (P < 0.01) mRNA expression and a tendency to increase in immunostaining for both angiotensin II and endothelin-1 in the left ventricles (16 wk). These findings suggest that fetal undernutrition activated the local cardiac angiotensin system-associated bioactive substances, which contributed, at least partly, to the development of cardiac remodeling in later life, in concert with the effects of increase in blood pressure.
Glomerular injury plays a pivotal role in the development of diabetic nephropathy. To elucidate molecular mechanisms underlying diabetic glomerulopathy, we compared glomerular gene expression profiles of db/db mice with those of db/m control mice at a normoalbuminuric stage characterized by hyperglycemia and at an early stage of diabetic nephropathy with elevated albuminuria, using cDNA microarray. In db/db mice at the normoalbuminuric stage, hypoxia-inducible factor-1␣ (HIF-1␣), ephrin B2, glomerular epithelial protein 1, and Pod-1, which play key roles in glomerulogenesis, were already upregulated in parallel with an alteration of genes related to glucose metabolism, lipid metabolism, and oxidative stress. Podocyte structure-related genes, actinin 4␣ and dystroglycan 1 (DG1), were also significantly upregulated at an early stage. The alteration in the expression of these genes was confirmed by quantitative RT-PCR. Through pioglitazone treatment, gene expression of ephrin B2, Pod-1, actinin 4␣, and DG1, as well as that of oxidative stress and lipid metabolism, was restored concomitant with attenuation of albuminuria. In addition, HIF-1␣ protein expression was partially attenuated by pioglitazone. These results suggest that not only metabolic alteration and oxidative stress, but also the alteration of gene expression related to glomerulogenesis and podocyte structure, may be involved in the pathogenesis of early diabetic glomerulopathy in type 2 diabetes. Diabetes
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