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GianCarlo Viberti

Publications and source records attributed to GianCarlo Viberti.

6 recordsLinked to original sources
PubMed2004

Sex differences in age-related stiffening of the aorta in subjects with type 2 diabetes.

Hypertension and type 2 diabetes are associated with increased aortic pulse wave velocity (PWV), a measure of aortic stiffness and a powerful risk factor for cardiovascular events. The association of hypertension with type 2 diabetes may obscure the degree to which diabetes rather than hypertension contributes to an elevated PWV. The objective of this study was to determine whether the presence of type 2 diabetes is associated with an elevated PWV compared with nondiabetic subjects matched for mean arterial blood pressure. PWV was determined by measuring carotid to femoral transit time using applanation tonometry in 186 subjects (104 women) with (n=93) and without (n=93) type 2 diabetes. Diabetic and nondiabetic subjects were matched for age and mean arterial pressure (to +/-5 years and 5 mm Hg, respectively). PWV was strongly correlated with age and mean arterial blood pressure (R=0.59 and 0.29 respectively, each P<0.0001). PWV increased significantly more with age in women with diabetes (slope of regression line+/-SE: 0.19+/-0.03 m x s(-1) x year(-1)) than in nondiabetic women (0.08+/-0.02 m x s(-1) x year(-1), P<0.01 for difference). In men, however, the age-related increase in PWV was similar in diabetic (0.15+/-0.03 m x s(-1) x year(-1)) and nondiabetic subjects (0.13+/-0.03 m. s(-1) x year(-1), P=NS). The interaction of diabetic status with age and with sex was significant (P=0.01). Type 2 diabetes is associated with a greater age-related stiffening of the aorta in women compared with men, and this is not explained by hypertension.

Adult↗
PubMed2003

GLUT-1 overexpression: Link between hemodynamic and metabolic factors in glomerular injury?

Mesangial matrix deposition is the hallmark of hypertensive and diabetic glomerulopathy. At similar levels of systemic hypertension, Dahl salt-sensitive but not spontaneously hypertensive rats (SHR) develop glomerular hypertension, which is accompanied by upregulation of transforming growth factor beta1 (TGF-beta1), mesangial matrix expansion, and sclerosis. GLUT-1 is ubiquitously expressed and is the predominant glucose transporter in mesangial cells. In mesangial cells in vitro, GLUT-1 overexpression increases basal glucose transport, resulting in excess fibronectin and collagen production. TGF-beta1 has been shown to upregulate GLUT-1 expression. We demonstrated that in hypertensive Dahl salt-sensitive (S) rats fed 4% NaCl (systolic blood pressure [SBP]: 236+/-9 mm Hg), but not in similarly hypertensive SHR (SBP: 230+/-10 mm Hg) or their normotensive counterparts (Dahl S fed 0.5% NaCl, SBP: 145+/-5 mm Hg; and Wistar-Kyoto, SBP: 137+/-3 mm Hg), there was an 80% upregulation of glomerular GLUT-1 protein expression (P< or =0.03). This was accompanied by a 2.7-fold upregulation of TGF-beta1 protein expression in glomeruli of DSH compared with DSN rats (P=0.02). TGF-beta1 expression was not upregulated and did not differ in the glomeruli of Wistar-Kyoto and SHR rats. As an in vitro surrogate of the in vivo hemodynamic stress imposed by glomerular hypertension, we used mechanical stretching of human and rat mesangial cells. We found that after 33 hours of stretching, mesangial cells overexpressed GLUT-1 (40%) and showed an increase in basal glucose transport of similar magnitude (both P< or =0.01), which could be blocked with an anti TGF-beta1-neutralizing antibody. These studies suggest a novel link between hemodynamic and metabolic factors that may cooperate in inducing progressive glomerular injury in conditions characterized by glomerular hypertension.

Animals↗
PubMed2002

Losartan reduces the burden and cost of ESRD: public health implications from the RENAAL study for the European Union.

Type 2 diabetes is the leading cause of end-stage renal disease (ESRD) in most industrialized countries in Europe. The RENAAL (Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan) Study evaluated the renal protective effects of losartan versus placebo on a background of non-ACE-I/non-AIIA conventional antihypertensive therapy in 1513 patients with type 2 diabetes and nephropathy. Losartan reduced the incidence of doubling of serum creatinine, end-stage renal disease (ESRD), or death by 16% (P=0.022) and reduced the risk of progression to ESRD, defined as the initiation of dialysis or transplantation, by 29% (P=0.002). We set out to estimate the potential effect of losartan on the burden and costs associated with ESRD over 3.5 years in the European Union (EU). The risk reduction in new cases of ESRD was calculated by combining type 2 diabetes population estimates for the EU with the percent absolute risk reduction of ESRD in patients treated with losartan as observed in RENAAL. The number of days each patient experienced ESRD was defined as the length of time from onset of ESRD until the minimum of death or 3.5 years. ESRD-free person-years avoided with losartan treatment were calculated by combining the population estimate with the ESRD days avoided divided by number of days in a year. ESRD costs from Germany were used to approximate the potential cost savings from reduced time with ESRD and fewer ESRD cases on a EU wide basis. There are approximately 700,000 diagnosed type 2 diabetes patients with proteinuria (urine albumin/creatinine >or=300 mg/g) in the EU. The addition of losartan to the treatment regimen of these patients is expected to lead to a reduction of 44,100 cases of ESRD, 64,400 fewer person-years with ESRD, and reduce ESRD-related costs by euro 2.6 billion over 3.5 years based on RENAAL data. Treatment with losartan not only reduced the incidence of ESRD, but also can result in substantial cost savings in the European Union.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2002

Podocyte number in normotensive type 1 diabetic patients with albuminuria.

We estimated glomerular cell number in 50 normotensive type 1 diabetic patients with raised albumin excretion rate (AER) and investigated any change after 3 years in a subgroup of 16 placebo-treated patients. Biopsies from 10 normal kidney donors were used as controls. Mesangial and endothelial cell number was increased in the 50 diabetic patients at the start of the study compared with control subjects. There was no difference in podocyte number. Glomerular volume was increased in diabetic patients, but surface area of glomerular basement membrane (GBM) underlying the podocytes did not differ between groups. AER correlated positively with mesangial cell number in microalbuminuric patients (r = 0.44, P = 0.012) and negatively with podocyte number in proteinuric patients (r = -0.48, P = 0.040). In the 16 placebo-treated patients, glomerular volume increased after 3 years owing to matrix accumulation and increased GBM surface area. Although overall cell number did not differ significantly from baseline, the decrease in podocyte number during follow-up correlated with AER at follow-up (r = -0.72, P = 0.002). In conclusion, cross-sectional analysis of podocyte number in type 1 diabetic patients with raised AER but normal blood pressure shows no significant reduction compared with nondiabetic control subjects. Longitudinal data provide evidence for an association between podocyte loss and AER, but whether cellular changes are a response to, a cause of, or concomitant with the progression of nephropathy remains uncertain.

Adult↗