Giancarlo Tonolo

Effects of Cilazapril and Amlodipine on Kidney Function in Hypertensive NIDDM Patients

Contrasting information has been reported concerning the course of renal function in NIDDM with hypertension alone or in association with renal damage. The aim of the present study was to elucidate the course of the glomerular filtration rate (GFR) in hypertensive NIDDM patients during antihypertensive therapy. Furthermore, we compared the effects of ACE inhibitors (cilazapril, Inibace, Roche, Milan, Italy) and Ca2+-channel blockers (amlodipine, Norvasc, Pfizer, Rome, Italy). Of the hypertensive NIDDM patients attending the outpatients clinic of the internal medicine departments of the University of Padova and Sassari, 44 participated in the present study. Of these patients, 26 were normoalbuminuric and 18 microalbuminuric. They were randomly treated with either cilazapril or amlodipine. The target of antihypertensive treatment was a value <140 mmHg for systolic and 85 mmHg for diastolic blood pressure (BP). Microalbuminuria was defined as an albumin excretion rate (AER) between 20 and 200 μg/min. GFR was measured by plasma clearance of 51Cr-labeled EDTA at baseline and every 6–12 months during a 3-year follow-up interval. A significant decrease was observed in the values of GFR, AER, and systolic and diastolic BP in normoalbuminuric and microalbuminuric patients during antihypertensive therapy. The GFR fall in the overall population of NIDDM patients was significantly and inversely related to the decrease of mean BP (diastolic + 1/3 pulse pressure) (r = −0.80, P < 0.0001) but not to that of HbA1c, triglycerides, and BMI. The GFR decline (mean ± SE) per year in the normoalbuminuric patient was 2.03 ± 0.66 ml · min−1 · 1.73 m−2 (95% CI 0.92–3.17) during cilazapril and 2.01 ± 0.71 ml · min−1 · 1.73 m−2 (95% CI 0.82–3.11) during amlodipine therapy. The GFR decline per year in the microalbuminuric patient was 2.15 ± 0.69 ml · min−1 · 1.73 m−2 (95% CI 0.86–3.89) during cilazapril and 2.33 ± 0.83 ml · min−1 · 1.73 m−2 per year (95% CI 1.03–3.67) during amlodipine therapy. Cilazapril and amlodipine lowered AER to a similar extent in normoalbuminuric and microalbuminuric patients. No significant changes were observed concerning other clinical and biochemical features between the two antihypertensive therapies and particularly HbA1c, BMI, triglycerides, and cholesterol plasma values. These results support the tenet that arterial hypertension plays a pivotal role in contributing to renal damage in NIDDM, even when AER is normal. However, the degree of BP control, with both cilazapril and amlodipine, can successfully delay the slope of GFR decline in hypertensive NIDDM patients with or without incipient nephropathy.

Lipoprotein metabolism during normal pregnancy

OBJECTIVE We sought to investigate the changes in circulating serum lipids and lipoproteins, including lipoprotein (a), and low-density lipoprotein size in women during normal pregnancy. STUDY DESIGN Twenty-two women (mean age, 31 +/- 5 years; 13 primiparous subjects) were studied during uncomplicated pregnancy with normal outcome. Twenty-four nulliparous women of similar age (31 +/- 4 years) were studied as control subjects. RESULTS Serum triglycerides and total and low-density lipoprotein cholesterol increased significantly during pregnancy in all women. Women with changes in low-density lipoprotein during the second and third trimesters showed a more marked increase in serum triglycerides, and this effect was slightly more evident in the multiparous subjects. No other differences were evident between primiparous and multiparous women apart from high-density lipoprotein cholesterol levels, which were slightly decreased in the latter subjects. CONCLUSIONS Our results show that during normal pregnancy, the increase in plasma triglycerides may lead to the appearance of the atherogenic dense low-density lipoproteins in a subgroup of women. We suggest that the observed changes in low-density lipoprotein patterns during pregnancy might be used to identify those women who later in life will have these atherogenic small and dense low-density lipoproteins.

Insulin sensitivity and glucose effectiveness: minimal model analysis of regular and insulin-modified FSIGT

The minimal model is widely used to evaluate insulin action on glucose disappearance from frequently sampled intravenous glucose tolerance tests (FSIGT). The common protocols are a regular (rFSIGT, single injection of 0.3 g/kg of glucose) and an insulin-modified test (mFSIGT, with an additional insulin administration at 20 min). This study compared the insulin sensitivity index (SI) and glucose effectiveness (SG) obtained in the same individual (16 normal subjects) with the two tests. SI was 7.11 ± 0.80 10-4 ⋅ min-1 ⋅ μU-1 ⋅ ml in rFSIGT and 6.96 ± 0.83 in mFSIGT ( P = 0.656), regression r = 0.92, P < 0.0001; SG was 0.0260 ± 0.0028 min-1 and 0.0357 ± 0.0052, respectively, statistically different ( P = 0.013) but still with a good regression ( r = 0.66, P = 0.0051). SG and insulin amount during the early period correlated ( r = 0.6, P = 0.015 in rFSIGT and r = 0.76, P = 0.0006 in mFSIGT). In summary, both FSIGTs with minimal model analysis provide the same SI, which is a very robust index. SG was different by 28% due probably to the relationship between SG and the amount of circulating insulin. In studies comparing groups, the simpler rFSIGT can still be used with the advantage of accounting for endogenous insulin, thus offering the possibility of direct inferences on the β-cell activity.The minimal model is widely used to evaluate insulin action on glucose disappearance from frequently sampled intravenous glucose tolerance tests (FSIGT). The common protocols are a regular (rFSIGT, single injection of 0.3 g/kg of glucose) and an insulin-modified test (mFSIGT, with an additional insulin administration at 20 min). This study compared the insulin sensitivity index (SI) and glucose effectiveness (SG) obtained in the same individual (16 normal subjects) with the two tests. SI was 7.11 +/- 0.80 10(-4).min-1.microU-1.ml in rFSIGT and 6.96 +/- 0.83 in mFSIGT (P = 0.656), regression r = 0.92, P < 0.0001; SG was 0.0260 +/- 0.0028 min-1 and 0.0357 +/- 0.0052, respectively, statistically different (P = 0.013) but still with a good regression (r = 0.66, P = 0.0051). SG and insulin amount during the early period correlated (r = 0.6, P = 0.015 in rFSIGT and r = 0.76, P = 0.0006 in mFSIGT). In summary, both FSIGTs with minimal model analysis provide the same SI, which is a very robust index. SG was different by 28% due probably to the relationship between SG and the amount of circulating insulin. In studies comparing groups, the simpler rFSIGT can still be used with the advantage of accounting for endogenous insulin, thus offering the possibility of direct inferences on the beta-cell activity.

Clustering of albumin excretion rate abnormalities in Caucasian patients with NIDDM

Summary Proteinuria and nephropathy have been found to cluster in families of non-insulin-dependent diabetic (NIDDM) Pima Indian, and in Caucasian insulin-dependent diabetic (IDDM) patients. No information is at present available for Caucasian NIDDM patients. The aim of the present study was to determine whether micro-macroalbuminuria (AER + ) is associated with albumin excretion rate abnormalities in diabetic and non-diabetic siblings of probands with NIDDM and AER + . We identified 169 Caucasian families with one NIDDM proband (the patient with longest known NIDDM duration) (101 families with only NIDDM siblings, 33 families with both NIDDM and non-NIDDM siblings and 35 families with only non-NIDDM siblings). Of the probands 56 had AER + [Prob-NIDDM-(AER + )], 78 had AER– [Prob-NIDDM-(AER–)], 74 siblings of Prob-NIDDM-(AER + ), and 113 siblings of Prob-NIDDM-(AER–) also had NIDDM. Data on albuminuria and retinopathy from multiple sibling pairs when the size of the sibship was more than two was adjusted according to a weighting factor. The odds ratio for AER + , in siblings of Prob-NIDDM-(AER + ) adjusted for age, hypertension, glycated haemoglobin A1 c and other confounding variables was 3.94 (95 % confidence intervals: 1.93–9.01) as compared to siblings of Prob-NIDDM-(AER–). The 74 siblings of Prob-NIDDM-(AER + ) had higher prevalence of proliferative retinopathy than siblings of Prob-NIDDM-(AER–) (14 vs 2 %; p < 0.01). We also identified 66 non-diabetic siblings of 41 NIDDM probands with AER + and 36 non-diabetic siblings of 27 NIDDM probands with AER–. Albumin excretion was two times higher, although still within the normal range, in the non-diabetic siblings of Prob-NIDDM-(AER + ) than in siblings of Prob-NIDDM-(AER–) [median = 13.5 (range 0.5–148) vs 6.6 (range 1–17) μg/min (p < 0.05)]. In conclusion higher rates of albumin excretion aggregate in Caucasian families with NIDDM. Proliferative retinopathy is more frequently observed in families showing a clustering of AER + and NIDDM. These findings suggest that familial factors play a role in the pathogenesis of renal and retinal complications in NIDDM. [Diabetologia (1997) 40: 816–823]

Radio-immunoassay for plasma alpha human atrial natriuretic peptide: a comparison of direct and pre-extracted methods.

Plasma atrial natriuretic peptide (ANP) concentrations were measured by both direct radio-immunoassay and with pre-extraction of the peptide from plasma using C18 reverse phase columns. Peptide concentrations were measured in normal subjects (including a group of eight volunteers who received an intravenous infusion of 0.9% NaCl solution), patients with renal failure (including a group with end-stage disease undergoing renal dialysis) and patients with a spectrum of cardiac dysfunction. The overall correlation of results from direct and extracted assay methods was good. However, absolute values from extracted assays were significantly lower than from parallel direct assays. This discrepancy was due to interference from platelets and from another, as yet unidentified, plasma component demonstrated by gel filtration experiments. Extraction of the peptide from plasma by C18 columns largely eliminated these sources of interference and was particularly important for accurate measurement of peptide concentrations within the normal range. Plasma peptide concentrations were elevated in cardiac and renal failure, fell with renal dialysis and rose in normal subjects challenged with an intravenous isotonic fluid load. These findings suggest that ANP participates in the regulation of body fluid volumes and arterial pressure.

Tissue kallikrein is essential for invasive capacity of circulating proangiogenic cells.

Rationale: Homing of proangiogenic cells (PACs) is guided by chemoattractants and requires proteases to disrupt the extracellular matrix. The possibility that PAC recruitment involves an interaction between proteases and chemotactic factor receptors remains largely unexplored. Objective: To determine the role of human tissue kallikrein (hK1) in PAC invasion and its dependency on kinin receptor signaling. Methods and Results: Human mononuclear cells (MNCs) and culture-selected PACs express and release mature hK1 protein. HK1 gene (KLK1) silencing reduced PACs migratory, invasive, and proangiogenic activities. KLK1-knockout mouse bone marrow–derived MNCs showed similar impairments and were unable to support reparative angiogenesis in a mouse model of peripheral ischemia. Conversely, adenovirus-mediated KLK1 (Ad.KLK1) gene transfer enhanced PAC-associated functions, whereas the catalytically inactive variant R53H-KLK1 was ineffective. HK1-induced effects are mediated by a kinin B2 receptor (B2R)-dependent mechanism involving inducible nitric oxide synthase and metalloproteinase-2 (MMP2). Lower hK1 protein levels were observed in PACs from type 2 diabetic (T2D) patients, whereas KLK1 mRNA levels were similar to those of healthy subjects, suggesting a post-transcriptional defect. Furthermore, B2R is normally expressed on T2D-PACs but remains uncoupled from downstream signaling. Importantly, whereas Ad.KLK1 alone could not restore T2D-PAC invasion capacity, combined KLK1 and B2R expression rescued the diabetic phenotype. Conclusions: This study reveals new interactive components of the PACs invasive machinery, acting via protease- and kinin receptor–dependent mechanisms.

Biliopancreatic diversion preserving the stomach and pylorus in the treatment of hypercholesterolemia and diabetes type II: Results in the first 10 cases

Background: Besides weight loss Scopinaros operation produces correction of hypercholesterolemia and noninsulin dependent diabetes mellitus in all patients who suffer from these conditions. These results encouraged us to perform biliopancreatic diversion (BPD) without gastric resection, thus preserving the functions of the stomach and pylorus in moderately overweight patients with hypercholesterolemia associated with diabetes type II and hypertriglyceridemia. Methods: Between March 1996 and July 1997 we performed BPD without gastric resection on 10 moderately overweight patients [mean body mass index (BMI) = 33.2 kg/m2]. All patients had suffered from hypercholesterolemia and hypertriglyceridemia for more than 5 years. Ten patients suffered from diabetes type II; four of them had had insulin treatment or oral anti-diabetic agents; the other patients all had hyperglycaemia in the fasted state and diabetes confirmed by preoperative oral glucose tolerance test (OGTT). Five patients suffered from hypertension. Results: In all patients, cholesterol and triglyceride levels returned to normal within the first postoperative month. Glycemia also stabilized at normal values in nine patients within the early weeks after surgery. One patient who took 70 U of insulin reduced his daily intake to 35 U 2 months postoperatively. In all patients blood pressure returned to normal. Weight loss was predictably slight (10-15 kg). Conclusions: Our experience with the procedure found that this new method seems to be as effective in controlling lipidic metabolism and diabetes II as the original version of BPD. As expected, weight loss is only moderate, so that the modified BPD is not suitable for very obese patients.

Effects of Hoe 140, a bradykinin B2‐receptor antagonist, on renal function in conscious normotensive rats

1 . The present study was designed to determine if endogenous kinins are involved in the regulation of arterial blood pressure and renal function in conscious rats given deoxycorticosterone enantate (DOC, 25 mg kg−1, s.c., weekly) or vehicle for two weeks. 2 . The bradykinin B2‐receptor antagonist, d‐Arg[Hyp3,Thi5,d‐Tic7,Oic8]‐bradykinin (Hoe 140), at a dose of 300 μg kg−1, s.c., blocked the hypotensive effect of 300 ng kg−1 bradykinin i.a., but it did not alter the blood pressure lowering action of 300 ng kg−1 acetylcholine or prostaglandin E2. Inhibition of the response to bradykinin persisted up to 6 h after the administration of Hoe 140. 3 . Administration of 300 μg kg−1 Hoe 140 s.c. four times a day did not alter mean blood pressure, renal blood flow, or renal function in rats given DOC‐vehicle. However, it decreased urinary volume by 70% (from 48.2 ± 3.8 to 14.3 ± 3.7 ml 24 h−1, P < 0.01) and urinary secretion of sodium by 54% (from 1.02 ± 0.05 to 0.47 ± 0.16 mmol 24 h−1, P < 0.01) and potassium by 30% (from 2.93 ± 0.15 to 2.04 ± 0.15 mmol 24 h−1, P < 0.05) in DOC‐treated rats. Mean blood pressure, glomerular filtration rate and total renal blood flow remained unchanged. 4 . Our results suggest that endogenous kinins play a role in the regulation of renal excretion of water and sodium in the presence of elevated levels of DOC.

Plasma lipid composition and LDL oxidation.

Abstract Low-density lipoprotein (LDL) oxidation in vivo depends on lipid composition and on plasma antioxidant status. The aim of our study was to investigate the relationship between plasma lipid composition and LDL oxidation and, in particular, to explore whether LDL-cholesterol/triglycerides ratio (LDL-C/TG) and LDL-cholesterol/high-density lipoprotein (HDL)-cholesterol ratio (LDL-C/HDL-C) can be used as predictive parameters of LDL oxidation in vivo. In 87 volunteers over a wide range of age plasma lipids and LDL oxidation were studied. Blood was collected after 12 h overnight fast. LDL oxidation was estimated by the level of conjugated diene (BDC) in the lipid fraction isolated from plasma after gradient ultracentrifugation. The results were expressed as μmol/l (BDC/l) to evaluate the level of oxidized LDL, and as nmol of BDC for mg of LDL-cholesterol (BDC/LDL-C) for the evaluation of LDL oxidation degree. BDC/l correlated significantly with age, total and LDL-C, apolipoprotein B and TG, while BDC/LDL-C negatively correlated with total cholesterol, apolipoprotein B, LDL/TG and LDL/HDL ratios. Age of subjects significantly correlated with total and LDL-C and apolipoprotein B. TG have a significant inverse correlation with HDL-C. Our results support the hypothesis that among the several factors involved in LDL oxidation the most important determinants are LDL/TG. Plasma triglycerides appear to be very important even when circulating cholesterol levels are within normal limits. Moreover, we found that the LDL/HDL ratio is also very important with regard to the putative protective role of HDL against LDL oxidation in vivo. In conclusion, plasma lipid parameters must be evaluated not only for their absolute values but also for their mutual ratios as expression of plasma lipid homeostasis. Both LDL/TG and LDL/HDL ratios can be used as predictive parameters of in vivo LDL oxidation.

Effect of endothelin on regional hemodynamics and renal function in awake normotensive rats

Summary: The effects of endothelin on regional hemodynamics and renal function were studied in awake normotensive rats. Intravenous injection of endothelin (700 pmol/kg) transiently lowered mean blood pressure (from 108 ± 2 to 84 ± 2 mm Hg, p < 0.01), due to a reduction in total vascular resistance (38 ± 1%, p < 0.01), and increased stroke volume (29 ± 5%, p < 0.01) and heart rate (from 399 ± 18 to 447 ± 18 bpm, p < 0.05); mesenteric and renal blood flow was reduced (37 ± 13, p < 0.05 and 63 ± 5%, p < 0.01), whereas carotid blood flow was increased (78 ± 5%, p < 0.01). This effect was followed by long-lasting hypertension due to increased total vascular resistance (112 ± 19%, p < 0.01); stroke volume, mesenteric, and renal blood flow were reduced (34 ± 5, 41 ± 4, and 58 ± 4%, respectively, p < 0.05) and carotid blood flow returned to basal levels. Bilateral nephrectomy enhanced the initial hypotensive effect. Pretreatment with nifedipine blocked the hypertensive effect, whereas bilateral nephrectomy did not. A subpressor dose of endothelin (70 pmol/kg) had no effect on stroke volume, mesenteric blood flow, glomerular filtration rate, and plasma renin activity; carotid blood flow was transiently increased (48 ± 16%, p < 0.05), then returned to basal levels; renal blood flow decreased (22 ± 6 and 15 ± 4% at 30 s and 10 min, respectively p < 0.05). Our data show a heterogeneity in the response of regional vascular beds to endothelin, the renal and mesenteric compartments being very sensitive to its vasoconstricting action. Endothelin, acting as paracrine or endocrine hormone, might have an important role in the pathogenesis of high blood pressure.