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1.
Diabet Med ; 19(9): 752-7, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12207812

ABSTRACT

AIMS: To evaluate the effects of gliclazide on oxidative status and vascular response to systemic administration of L-arginine, the natural precursor of nitric oxide (NO), in Type 2 diabetic patients. METHODS: Thirty Type 2 diabetic patients received glibenclamide (n = 15) or gliclazide (n = 15) in a 12-week, randomized, observer-blinded, parallel study. Plasma lipid peroxides, total radical-trapping anti-oxidant parameter (TRAP), and blood pressure responses to an intravenous bolus of L-arginine were measured pre- and post-treatment. RESULTS: At 12 weeks, gliclazide patients had lower plasma lipid peroxides (13.3 +/- 3.8 micro mol/l vs. 19.2 +/- 4.3 micro mol/l; P = 0.0001) and higher plasma TRAP (1155.6 +/- 143.0 micro mol/l vs. 957.7 +/- 104.3 micro mol/l; P = 0.0001) than the glibenclamide patients. Gliclazide but not glibenclamide significantly reduced systolic and diastolic blood pressure (P = 0.0199 and P = 0.00199, respectively, two-way repeated measures analysis of variance) in response to intravenous L-arginine. CONCLUSIONS: Gliclazide reduces oxidative stress in Type 2 diabetic patients by improving plasma anti-oxidant status. This effect is associated with enhanced NO-mediated vasodilation.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Gliclazide/therapeutic use , Hypoglycemic Agents/therapeutic use , Adult , Aged , Antioxidants/analysis , Arginine/pharmacology , Blood Pressure/drug effects , Diabetes Mellitus, Type 2/blood , Free Radicals/blood , Glyburide/therapeutic use , Humans , Injections, Intravenous , Lipid Peroxides/blood , Male , Middle Aged , Nitric Oxide/metabolism , Oxidative Stress/drug effects , Vasodilation/drug effects
2.
Diabetologia ; 45(8): 1120-7, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12189442

ABSTRACT

AIMS/HYPOTHESIS: Hyperhomocysteinaemia increases cardiovascular risk in Type II (non-insulin-dependent) diabetes mellitus by augmenting oxidative stress and reducing nitric oxide availability. In vitro, nitric oxide decreases homocysteine by its conversion to the vasodilative and antioxidant compound S-nitrosohomocysteine. We investigated whether or not changes in nitric oxide availability decrease homocysteine concentrations in vivo. METHODS: The study group consisted of 20 normotensive, normolipidaemic, non-atherosclerotic Type II diabetic patients in good metabolic control (16 men, 51.2+/-1.4 years) and 15 healthy subjects (12 men, 48.1+/-1.5 years). Circulating concentrations of homocysteine, nitrite+nitrate and sulphydryl groups, a marker of oxidative stress, were assessed at baseline and then 5', 10', 30' and 60' after the intravenous infusion of either L-arginine (3 g in 10 ml saline), the nitric oxide precursor, or vehicle according to a double-blind cross-over randomized protocol. RESULTS: At baseline diabetic patients showed lower plasma sulphydryl group concentrations (491.8+/-16.9 vs 551.3+/-21.0 micro mol/l, p<0.04) and nitrite+nitrate (21.4+/-0.8 vs 29.5+/-0.9 micro mol/l, p<0.0001) and higher total homocysteine concentrations (11.1+/-0.5 vs 8.3+/-0.6 micro mol/l, p<0.002) than the control subjects. After L-arginine infusion, blood pressure levels and total homocysteine concentrations ( p< or =0.05) decreased (peak at 5' and 30', respectively) whereas nitric oxide and sulphydryl group concentrations ( p< or =0.003) increased (peak at 10' and 30', respectively) in the patients and control subjects. CONCLUSION/INTERPRETATION: Acute L-arginine infusion in both Type II diabetic patients and healthy subjects decreases plasma total homocysteine concentrations, counteract oxidative stress and increases the availability of nitric oxide.


Subject(s)
Arginine/pharmacology , Diabetes Mellitus, Type 2/metabolism , Homocysteine/blood , Nitric Oxide/biosynthesis , Oxidative Stress , Arginine/administration & dosage , Blood Pressure/drug effects , Cross-Over Studies , Double-Blind Method , Female , Humans , Infusions, Intravenous , Male , Middle Aged , Nitrates/blood , Nitrites/blood , Osmolar Concentration , Reference Values , Sulfhydryl Compounds/blood
3.
Diabetologia ; 43(8): 1000-4, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10990077

ABSTRACT

AIMS/HYPOTHESIS: Induction of tolerance to insulin is achievable in animal models of Type I (insulin-dependent) Diabetes mellitus by oral treatment with this hormone, which can lead to prevention of the disease. In the Diabetes Prevention Trial of Type I diabetes (DPT-1), oral insulin is given with the aim of preventing disease insurgence. We investigated whether if given at diagnosis of Type I diabetes in humans, oral insulin can still act as a tolerogen and therefore preserve residual beta-cell function, which is known to be substantial at diagnosis. METHODS: A double-blind trial was carried out in patients (mean age +/- SD: 14 +/- 8 years) with recent-onset Type I diabetes to whom oral insulin (5 mg daily) or placebo was given for 12 months in addition to intensive subcutaneous insulin therapy. A total of 82 patients with clinical Type I diabetes ( < 4 weeks duration) were studied. Basal C peptide and glycated haemoglobin were measured and the insulin requirement monitored every 3 months up to 1 year. Insulin antibodies were also measured in 27 patients treated with oral insulin and in 18 patients receiving placebo at the beginning of the trial and after 3, 6 and 12 months of treatment. RESULTS: The trial was completed by 80 patients. Overall and without distinction between age at diagnosis, at 3, 6, 9 and 12 months baseline mean C-peptide secretion in patients treated with oral insulin did not differ from that of those patients treated with placebo. In patients younger than 15 years a tendency for lower C-peptide values at 9 and 12 months was observed in the oral insulin group. Insulin requirement at 1 year was similar between the two groups as well as the percentage of glycated haemoglobin. Finally, IgG insulin antibodies were similar in the two groups at each time point. CONCLUSION/INTERPRETATION: The results of this study indicate that the addition of 5 mg of oral insulin does not modify the course of the disease in the first year after diagnosis and probably does not statistically affect the humoral immune response against insulin.


Subject(s)
Diabetes Mellitus, Type 1/drug therapy , Insulin/administration & dosage , Islets of Langerhans/metabolism , Administration, Oral , Adolescent , Adult , Age of Onset , Blood Glucose/metabolism , C-Peptide/blood , Child , Diabetes Mellitus, Type 1/blood , Double-Blind Method , Female , Glycated Hemoglobin/analysis , Humans , Injections, Subcutaneous , Insulin/therapeutic use , Islets of Langerhans/drug effects , Italy , Male
4.
Diabetologia ; 42(10): 1235-9, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10525665

ABSTRACT

AIMS/HYPOTHESIS: To evaluate the effects of insulin on vascular cell adhesion molecule-1 expression by cultured human vascular endothelial cells and soluble vascular cell adhesion molecule-1 release in vivo. METHODS: Human vascular endothelial cells derived from umbilical cord veins were incubated with either insulin (from 10(-6) to 10(-9) mol/l) or tumour necrosis factor-alpha (5 ng/ml) for 6 to 24 h. Plasma soluble vascular cell adhesion molecule-1 concentrations were evaluated in 12 non-insulin-dependent diabetic patients (8 men, 4 women, mean age 47.1 +/- 7.7 years) and 12 healthy volunteers matched for age, sex and weight (7 men, 5 women, mean age 42.2 +/- 7.2 years) before and after a 2-h euglycaemic hyperinsulinaemic clamp. RESULTS: Transcriptional activities of nuclear factor-kappaB luciferase and vascular adhesion molecule-1 luciferase statistically significantly increased after incubation with tumour necrosis factor-alpha. By contrast, a slight increment of nuclear factor-kappaB luciferase (mean: 1.8 +/- 0.3 fold) but not of vascular cell adhesion molecule-1 luciferase transcriptional activities were detected in cells stimulated with insulin. Soluble vascular cell adhesion molecule-1 concentrations in cell supernatants increased after tumour necrosis factor-alpha but not insulin stimulation. In vivo, baseline plasma soluble vascular cell adhesion molecule-1 concentrations were higher (p = 0.03) in non-insulin-dependent patients (708.7 +/- 97.4 microg/l) than controls (632.1 +/- 65.2 microg/l) but were not related to fasting insulin concentrations and did not change during insulin infusion. CONCLUSION/INTERPRETATION: The increased concentrations of circulating soluble vascular cell adhesion molecule-1 indicates that the vascular endothelium is activated in non-insulin dependent diabetic patients. Our in vitro and in vivo findings show that vascular cell adhesion molecule-1 activation cannot be due to hyperinsulinaemia. [Diabetologia (1999) 42: 1235-1239]


Subject(s)
Endothelium, Vascular/drug effects , Insulin/pharmacology , Vascular Cell Adhesion Molecule-1/biosynthesis , Vascular Cell Adhesion Molecule-1/blood , Adult , Blood Glucose , Cells, Cultured , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/metabolism , Dose-Response Relationship, Drug , Endothelium, Vascular/metabolism , Female , Gene Expression/drug effects , Genes, Reporter , Glucose Clamp Technique , Glycated Hemoglobin/metabolism , Humans , Insulin/blood , Male , Middle Aged , NF-kappa B/biosynthesis , NF-kappa B/genetics , Time Factors , Transfection , Tumor Necrosis Factor-alpha/pharmacology
5.
Diabetologia ; 41(11): 1392-6, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9833950

ABSTRACT

To assess in vivo effects of antioxidants on vascular cell adhesion molecule (VCAM)-1 expression, circulating soluble VCAM-1 and intraerythrocytic reduced glutathione (GSH) and GSH disulphide (GSSG) concentrations were evaluated in non-insulin-dependent diabetic patients without complications (9 men, 6 women, 48 +/- 6 years old) before and after 1 month of either oral N-acetyl-L-cysteine (1.200 mg/day) or placebo treatments, given in randomized, cross-over, double-blind fashion. Ten healthy subjects (7 men, 3 women, 52 +/- 4 years old) served as control subjects. Baseline plasma VCAM-1 concentrations were higher (p = 0.007) in non-insulin-dependent diabetic patients (707.9 +/- 52.5 ng/ml) than in control subjects (627.3 +/- 84.6 ng/ml). Intraerythrocytic GSSG content was higher (non-insulin dependent diabetic patients: 0.618 +/- 0.185 micromol/g Hb; control subjects: 0.352 +/- 0.04 micromol/g Hb, p = 0.0002), whereas intraerythrocytic GSH concentrations were lower (p = 0.001) in non-insulin dependent diabetic patients (6.0 +/- 0.7 micromol/g Hb) than in control subjects (7.1 +/- 0.5 micromol/g Hb). The mean GSH:GSSG ratio was also lower (p = 0.0001) in the first (10.9 +/- 4.5) than in the second group (20.2 +/- 1.4). Circulating VCAM-1 and intraerythrocytic GSH concentrations were negatively correlated in non-insulin diabetic patients (r = 0.605, p = 0.01). Treatment with N-acetyl-L-cysteine decreased plasma VCAM-1 (p = 0.01) and intraerythrocytic GSSG (p = 0.006) but increased GSH concentrations (p = 0.04) and the GSH:GSSG ratio (p = 0.004) in non-insulin dependent diabetic patients. Our data indicate that the vascular endothelium is activated in non-insulin dependent diabetes. Antioxidant treatment counterbalanced such endothelial activation. Thus, antioxidant agents might protect against oxidant-related upregulation of endothelial adhesion molecules and slow down the progression of vascular damage in non-insulin dependent diabetes.


Subject(s)
Acetylcysteine/therapeutic use , Diabetes Mellitus, Type 2/blood , Free Radical Scavengers/therapeutic use , Oxidative Stress/drug effects , Vascular Cell Adhesion Molecule-1/blood , Acetylcysteine/administration & dosage , Acetylcysteine/pharmacology , Administration, Oral , Adult , Blood Glucose/metabolism , Blood Pressure , Cholesterol/blood , Cross-Over Studies , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/physiopathology , Double-Blind Method , Erythrocytes/drug effects , Erythrocytes/metabolism , Female , Free Radical Scavengers/administration & dosage , Free Radical Scavengers/pharmacology , Glutathione Disulfide/blood , Humans , Insulin/blood , Male , Middle Aged , Oxidative Stress/physiology , Reference Values , Triglycerides/blood
6.
Am J Hypertens ; 11(8 Pt 1): 983-8, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9715792

ABSTRACT

To evaluate the role of circulating and renal endothelin-1 (ET-1) in early diabetic nephropathy, plasma ET-1 levels and urinary ET-1 excretion were evaluated in lean, normotensive patients affected by non-insulin-dependent diabetes (NIDDM) either with (n = 9, NIDDM+) or without microalbuminuria (n = 18, NIDDM-); in never-treated, lean, essential hypertensive patients with (n = 12, EH+) or without microalbuminuria (n = 10, EH-); and in healthy volunteers (n = 12). Results showed higher plasma ET-1 levels in NIDDM+ (1.97 +/- 0.58 pg/mL) than in NIDDM- (1.59 +/- 0.14 pg/mL, P = .013), EH+ (1.40 +/- 0.21 pg/mL, P = .005), EH- (0.91 +/- 0.19 pg/mL, P < .0001), and controls (0.60 +/- 0.10 pg/mL, P < .0001). The circulating ET-1 concentration was also higher in EH+ than EH- and controls (P < .0001). Urinary ET-1 excretion did not differ (P = .387, NS) between NIDDM+ (48.5 +/- 20.1 pg/min) and NIDDM- (40.9 +/- 21.6 pg/min), but was significantly reduced (P < .0001) in both groups compared with controls (70.0 +/- 15.5 pg/min). Similar findings were observed in hypertensive subgroups. No correlations were found between urinary ET-1 and other variables, including plasma ET-1 levels, in all groups. In conclusion, NIDDM+ is accompanied by a significant increase in plasma ET-1 levels. A significant elevation of circulating ET-1 concentration was evident also in NIDDM-, suggesting that early abnormalities of ET-1 production might precede the microalbuminuric phase of diabetes-related renal damage.


Subject(s)
Albuminuria/metabolism , Diabetes Mellitus, Type 2/metabolism , Diabetic Nephropathies/metabolism , Endothelin-1/blood , Endothelin-1/urine , Hypertension/metabolism , Adult , Aged , Female , Humans , Male , Middle Aged
7.
Metabolism ; 47(8): 993-7, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9711998

ABSTRACT

To evaluate the relationship between oxidative stress and glucose metabolism, insulin sensitivity and intraerythrocytic reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio were measured in 10 non-insulin-dependent diabetes mellitus (NIDDM) patients and 10 healthy subjects before and after the intravenous administration of GSH. In particular, after baseline insulin sensitivity was assessed by a 2-hour euglycemic hyperinsulinemic clamp, either glutathione (1.35 g x m2 x min(-1)) or placebo (saline) were infused over a period of 1 hour. The same protocol was repeated at a 1-week interval, in cross-over, according to a randomized, single-blind design. In healthy subjects, baseline intraerythrocytic GSH/GSSG ratio (P < .0005) and total glucose uptake (P < .005) were significantly higher than in NIDDM patients. In the same subjects, GSH infusion significantly increased total glucose uptake (from 37.1 +/- 6.7 micromol kg(-1) x min(-1) to 39.5 +/- 7.7 micromol x kg(-1) x min(-1), P < .05), whereas saline infusion was completely ineffective. In addition, the mean intraerythrocytic GSH/GSSG ratio significantly increased after GSH infusion (from 21.0 +/- 0.9 to 24.7 +/- 1.3, P < .05). Similar findings were found in diabetic patients, in whom GSH infusion significantly increased both total glucose uptake (from 25.3 +/- 9.0 micromol x kg(-1) x min(-1) to 31.4 +/- 10.0 micromol x kg(-1) x min(-1), P < .001) and intraerythrocytic GSH/GSSG ratio (from 14.8 +/- 4.1 to 21.7 +/- 6.7, P < .01). Pooling diabetic patients and controls, significant correlations were found between intraerythrocytic GSH/GSSG ratio and total glucose uptake (r = .425, P < .05), as well as between increments of the same variables after GSH infusion (r = .518, P < .05). In conclusion, our data support the hypothesis that abnormal intracellular GSH redox status plays an important role in reducing insulin sensitivity in NIDDM patients. Accordingly, intravenous GSH infusion significantly increased both intraerythrocytic GSH/GSSG ratio and total glucose uptake in the same patients.


Subject(s)
Diabetes Mellitus, Type 2/blood , Erythrocytes/metabolism , Glucose/metabolism , Glutathione/administration & dosage , Insulin Resistance , Adult , Cross-Over Studies , Female , Glucose Clamp Technique , Humans , Infusions, Intravenous , Male , Middle Aged , Single-Blind Method
8.
Metabolism ; 46(10): 1194-8, 1997 Oct.
Article in English | MEDLINE | ID: mdl-9322806

ABSTRACT

The current study aimed to evaluate whether nicotinamide adenine dinucleotide phosphate (NADPH) alteration in erythrocytes from patients with non-insulin-dependent diabetes mellitus (NIDDM) is responsible for the impaired glutathione (GSH) redox status, and to assess if short-term inhibition of the polyol pathway normalizes NADPH levels and GSH redox status via an amelioration of the NADPH/total NADP (tNADP) ratio. For this purpose, erythrocyte NADPH and GSH levels were measured in 18 NIDDM patients at baseline and then after 1 week of random double-blind assignment to treatment with either tolrestat (an aldose reductase inhibitor, 200 mg daily) (n = 12) or placebo (n = 6). A group of 16 healthy volunteers served as the control. In the basal condition, mean GSH (P < .0001) and NADPH (P < .0001) levels and NADPH/tNADP (P < .0001) and GSH/ glutathione disulfide (GSSG) (P < .005) ratios were lower in NIDDM patients than in control subjects. Tolrestat treatment increased GSH levels (P < .05 v placebo and baseline) and the NADPH/tNADP ratio (P < .05 v placebo and baseline). Interestingly, tolrestat-induced changes in GSH and NADPH levels and in GSH/GSSG and NADPH/tNADP ratios were significant only in patients who showed a decreased NADPH/tNADP ratio at baseline (n = 8). In these latter patients, we also found a direct correlation between percentage increments in GSH levels and NADPH/tNADP ratios after tolrestat treatment (r = .71, P < .05). In conclusion, our findings support the hypothesis that polyol pathway activation decreases NADPH and GSH levels. Accordingly, short-term inhibition of this enzymatic route increased both the GSH level and the NADPH/tNADP ratio. These changes were observable only in the subgroup of patients with an abnormal NADPH/tNADP ratio at baseline. Polyol pathway inhibition could be useful for decreasing oxidative stress in NIDDM.


Subject(s)
Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/drug therapy , Enzyme Inhibitors/therapeutic use , Erythrocytes/metabolism , Glutathione/analogs & derivatives , Glutathione/blood , NADP/blood , Naphthalenes/therapeutic use , Adult , Aged , Aldehyde Reductase/antagonists & inhibitors , Double-Blind Method , Enzyme Inhibitors/pharmacology , Erythrocytes/drug effects , Female , Glucosephosphate Dehydrogenase/blood , Glutathione Disulfide , Humans , Male , Middle Aged , Naphthalenes/pharmacology , Oxidation-Reduction , Reference Values
9.
Exp Clin Endocrinol Diabetes ; 105 Suppl 2: 40-2, 1997.
Article in English | MEDLINE | ID: mdl-9288543

ABSTRACT

Increased levels of endothelin (ET-1), a potent endothelium-derived vasoconstrictive peptide, have been found in plasma from non-insulin dependent diabetic (NIDDM) patients, suggesting that ET-1 might represent a new marker of diabetes-related vascular damage. To elucidate this topic, circulating ET-1 levels were evaluated in 16 NIDDM patients in good metabolic control without either cardiovascular risk factors (obesity, hypertension, smoking, hyperdislipidaemia, etc.) or diabetes-related damage of other districts and in 12 healthy subjects. Retinopathy was assessed by ophthalmological evaluation and its severity determined by Klein criteria. Resulting data showed higher levels of plasma ET-1 in NIDDM patients than in control subjects (0.80 +/- 0.13 vs 0.60 +/- 0.12 pg/mL, p < 0.001). Plasma ET-1 levels were directly correlated with retinopathy degrees in NIDDM patients affected by retinopathy (n = 10; r = 0.368; p = 0.02), and were significantly higher in these latter (n = 10) than in those without retinopathy (n = 6) (0.89 +/- 0.13 vs 0.71 +/- 0.19 pg/mL, p < 0.05). The increased levels of ET-1 could contribute to retinopathy development or, more probably, represent a marker of this diabetes-related complication.


Subject(s)
Diabetes Mellitus, Type 2/blood , Diabetic Retinopathy/blood , Diabetic Retinopathy/physiopathology , Endothelin-1/blood , Adult , Biomarkers/blood , Cardiovascular Diseases , Humans , Male , Middle Aged , Reference Values , Risk Factors
10.
Diabet Med ; 13(7): 642-5, 1996 Jul.
Article in English | MEDLINE | ID: mdl-8840098

ABSTRACT

It has been suggested that kallikrein-kinin system may influence carbohydrate metabolism via a kinin-mediated increment of insulin-mediated glucose uptake. To evaluate the effect of acute inhibition of the kallikrein-kinin system on insulin sensitivity, a randomized, placebo-controlled, double-blind study was performed in 15 male non-insulin-dependent diabetic patients. After basal evaluation of insulin sensitivity with a 2-h euglycaemic hyperinsulinaemic clamp (40 mU m-2 min-1), patients were infused either with aprotinin (200,000 U.I.C. as intravenous bolus injection) or placebo (10 ml isotonic saline) in a cross-over fashion, at 1 week intervals. After both saline and aprotinin infusions, insulin sensitivity was reassessed by continuing the euglycaemic hyperinsulinaemic clamp for a further 1 h. Resulting data showed that aprotinin significantly improved total glucose uptake (from 16.2 +/- 2.9 mumol kg min-1 to 20.6 +/- 4.9 mumol kg min-1 p < 0.01), and decreased metabolic clearance rate of insulin (from 586 +/- 57 ml m-2 min-1 to 442 +/- 155 ml m-2 min-1, p < 0.05). Thus, in spite of the suggested positive effects of kinins on insulin-mediated glucose uptake, acute inhibition of the kallikrein-kinins system resulted in a paradoxical increment of insulin sensitivity, which was probably mediated by the reduced metabolic clearance rate of insulin.


Subject(s)
Aprotinin/pharmacology , Blood Glucose/metabolism , Diabetes Mellitus, Type 2/metabolism , Hypoglycemic Agents/pharmacokinetics , Insulin/pharmacokinetics , Serine Proteinase Inhibitors/pharmacology , Adult , Aprotinin/administration & dosage , Blood Glucose/drug effects , C-Peptide/blood , C-Peptide/drug effects , C-Peptide/metabolism , Cross-Over Studies , Double-Blind Method , Glucose Clamp Technique , Humans , Hypoglycemic Agents/blood , Hypoglycemic Agents/metabolism , Insulin/blood , Insulin/metabolism , Male , Metabolic Clearance Rate , Middle Aged , Serine Proteinase Inhibitors/administration & dosage
11.
Diabetes Care ; 19(3): 226-30, 1996 Mar.
Article in English | MEDLINE | ID: mdl-8742566

ABSTRACT

OBJECTIVE: To evaluate the effects of captopril on circulating catecholamine levels in NIDDM patients and the possible relationship between captopril-related changes in circulating catecholamine levels and insulin sensitivity. RESEARCH DESIGN AND METHODS: Fourteen nonobese normotensive NIDDM men (aged 44.5 +/- 5.1 years) underwent a 2-h euglycemic-hyperinsulinemic clamp (40 mU.m-2.min-1). Baseline evaluation of insulin sensitivity was followed by the random assignment of each patient to either captopril or placebo treatment, according to a crossover double-blind design. Euglycemic-hyperinsulinemic clamp studies were then repeated for all patients after both placebo and captopril treatments. Plasma norepinephrine (NE) and epinephrine (E) levels were assessed before, during, and after each clamp. RESULTS: Resulting data showed that plasma catecholamine levels increased during baseline euglycemic-hyperinsulinemic clamp (NE: +23.6% time 0 vs. time 120 min, P < 0.05; E: +24.8% time 0 vs. time 120 min, P < 0.05). Captopril treatment significantly increased total glucose uptake (from 19.0 +/- 9.0 to 26.8 +/- 10.1 mmol.kg-1.min-1, P < 0.05) and reduced baseline plasma NE (P < 0.001) and E (P < 0.05) levels. However, the magnitude of the NE (+25.7% time 0 vs. time 120 min, P < 0.001) and E (+27.2% time 0 vs. time 120 min, P < 0.05) increments during euglycemic hyperinsulinemia were not affected by the drug. Percentage changes in the ratio of total body glucose uptake to circulating insulin levels and corresponding decrements of baseline plasma E levels after captopril therapy were negatively correlated (r = -0.57, P < 0.05). CONCLUSIONS: The reduction of circulating catecholamines could contribute, at least in part, to the captopril-related amelioration of insulin sensitivity.


Subject(s)
Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Captopril/therapeutic use , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/physiopathology , Epinephrine/blood , Norepinephrine/blood , Adult , Blood Glucose/metabolism , Cross-Over Studies , Diabetes Mellitus, Type 2/drug therapy , Glucose Clamp Technique , Humans , Infusions, Intravenous , Insulin/administration & dosage , Insulin/blood , Insulin/pharmacology , Male
12.
Diabetes Care ; 18(2): 226-33, 1995 Feb.
Article in English | MEDLINE | ID: mdl-7729302

ABSTRACT

OBJECTIVE: To evaluate whether or not insulin stimulates endothelin (ET)-1 secretion in vivo. RESEARCH DESIGN AND METHODS: Plasma ET-1 levels were evaluated in 16 lean normotensive men with non-insulin-dependent diabetes mellitus (NIDDM) (mean age 50.3 +/- 4.1 years) during either a 2-h euglycemic hyperinsulinemic clamp (40 mU insulin.m-2.min-1) or placebo infusion (50 ml isotonic saline) according to a single-blind randomized crossover protocol. RESULTS: Circulating ET-1 levels increased during the euglycemic hyperinsulinemic clamp (from 0.88 +/- 0.38 pg/ml at time 0 to 1.66 +/- 0.22 pg/ml and 1.89 +/- 0.99 pg/ml at 60 and 120 min, respectively [P < 0.05 vs. time 0]) and returned to baseline levels after the discontinuation of insulin infusion (0.71 +/- 0.22 pg/ml after a 30-min period of recovery [NS]). Compared with placebo, the euglycemic hyperinsulinemic clamp induced a significant increase in plasma ET-1 levels at 60 min (P < 0.0001) and 120 min (P < 0.0001). Changes in basal insulin levels and corresponding changes in circulating ET-1 levels after a 2-h euglycemic hyperinsulinemic clamp were significantly correlated (r = 0.771, P < 0.0001). A possible unfavorable effect of ET-1 on the tissue sensitivity to insulin-stimulated glucose uptake was suggested by the presence of a negative correlation between total glucose uptake and baseline ET-1 levels (r = -0.498, P < 0.05). CONCLUSIONS: Our findings indicate that circulating ET-1 levels significantly increase during euglycemic hyperinsulinemic clamp in men with NIDDM. The negative correlation between total glucose uptake and circulating ET-1 levels suggests that the peptide might exert negative effects on the insulin sensitivity of target tissues. The consequent increase in insulin secretion as well as the insulin-related ET-1 release from endothelial cells could favor the development of diabetes-related vascular lesions.


Subject(s)
Diabetes Mellitus, Type 2/blood , Endothelins/blood , Glucose Clamp Technique , Insulin/pharmacology , Blood Glucose/metabolism , Blood Pressure/drug effects , Case-Control Studies , Cross-Over Studies , Diabetes Mellitus, Type 2/physiopathology , Endothelins/metabolism , Humans , Infusions, Intravenous , Insulin/administration & dosage , Insulin/blood , Kinetics , Male , Middle Aged , Placebos , Reference Values , Single-Blind Method , Thinness , Time Factors
13.
Clin Auton Res ; 3(4): 249-54, 1993 Aug.
Article in English | MEDLINE | ID: mdl-8292880

ABSTRACT

The 24 h periodic pattern of blood pressure was studied in 44 patients with diabetes mellitus (14 type 1, 30 type 2; mean duration of disease 6.5 +/- 1.8 years) in good metabolic control but with abnormal cardiovascular reflex responses; of these 21 were normotensive and 23 hypertensive. All had abnormal responses to at least two out of four tests: deep breathing, lying to standing, Valsalva manoeuvre and postural hypotension. Two sex- and age-matched groups, consisting of 20 normotensive and 20 hypertensive diabetic patients without dysautonomia, were studied as controls. Each patient underwent ambulatory blood pressure monitoring for at least 24 h, using an auscultatory automatic device. Data were analysed using the sum of three periodic functions (Fourier partial sum). In the diabetic normotensive groups, the absolute blood pressure fell to its night-time minimum more rapidly, and increased to its morning maximum more slowly, in those with abnormal cardiovascular reflexes than in the controls (nightly blood pressure decrease -5.8/-4.7 vs. -3.8/-4.0 mmHg/h; increase 4.7/3.6 vs. 5.9/6.1 mmHg/h). The same behaviour was found in both hypertensive groups but the amplitude of the differences was more marked (blood pressure nocturnal decrease -7.7/-7.1 vs. -4.3/-3.9 mmHg/h; increase 3.2/2.1 vs. 5.8/4.3 mmHg/h). This analysis of 24 h ambulatory blood pressure data may be of value in diagnosis and evaluation of autonomic deficits.


Subject(s)
Autonomic Nervous System Diseases/physiopathology , Blood Pressure/physiology , Diabetic Neuropathies/physiopathology , Adult , Aged , Circadian Rhythm/physiology , Diabetes Mellitus, Type 1/physiopathology , Female , Fourier Analysis , Humans , Hypertension/complications , Hypertension/physiopathology , Male , Middle Aged , Models, Biological
14.
Acta Diabetol ; 28(3-4): 221-8, 1992.
Article in English | MEDLINE | ID: mdl-1576359

ABSTRACT

The aim of our study was to analyse the 24-h periodic pattern of blood pressure (BP) in diabetic patients with abnormal responses to cardiovascular reflexes, in order to evaluate the extent of the initial autonomic damage. We studied 44 patients with diabetes mellitus (14 insulin-dependent, 30 non-insulin-dependent; mean duration of disease 6.5 +/- 1.8 years) in good metabolic control (fasting glycaemia less than 140 mg/dl, postprandial glycaemia less than 180 mg/dl, fructosamine less than 285 mg/dl), divided into two subgroups, containing 21 normotensives (13 males and 8 females aged 28-72 years) and 23 hypertensives (13 males and 10 females aged 32-70 years) respectively. All patients showed abnormal responses to at least two out of four tests: deep breathing, lying to standing, Valsalva manoeuvre and postural hypotension. Two sex- and age-matched control groups were recruited, comprising 20 normotensive and 20 hypertensive diabetic patients without dysautonomia, respectively. The reference group consisted of 248 normotensives (135 males and 113 females, aged 18-76 years) and 212 mild-moderate hypertensives (130 males and 82 females, aged 27-66 years). Each patient underwent ambulatory BP monitoring for at least 24 h, using an auscultatory automatic device. Data concerning biological rhythms were analysed by means of periodic functions. We limited the Fourier partial sums to the first three harmonics.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Blood Pressure , Diabetes Mellitus, Type 1/physiopathology , Diabetes Mellitus, Type 2/physiopathology , Diabetic Neuropathies/physiopathology , Adult , Aged , Diastole , Female , Humans , Hypertension/physiopathology , Male , Middle Aged , Models, Cardiovascular , Posture , Reference Values , Sex Characteristics , Systole , Valsalva Maneuver
15.
Minerva Cardioangiol ; 38(12): 519-25, 1990 Dec.
Article in Italian | MEDLINE | ID: mdl-2092231

ABSTRACT

The Authors investigated the sensitivity of the ecg thoracic derivations of Condorelli in detecting non-Q myocardial infarction demonstrated by 2-D echocardiography and 201-TL scintigraphy. This technique showed a good reliability, allowing a useful diagnostic approach.


Subject(s)
Echocardiography , Heart/diagnostic imaging , Myocardial Infarction/diagnosis , Electrocardiography , Humans , Myocardial Infarction/diagnostic imaging , Radionuclide Imaging
16.
Minerva Cardioangiol ; 38(9): 373-8, 1990 Sep.
Article in Italian | MEDLINE | ID: mdl-2084578

ABSTRACT

The study compared echocardiography, specially echocardiokimography, and myocardial scintigraphy in the evaluation of the extent of chronic myocardial infarction. Eighteen subjects were enrolled and the following examinations performed: ECG, M- and B-mode echocardiography, echocardiokimography and myocardial scintigraphy with Tc-MIBI, a new perfusion radionuclide agent. We concluded: 1) accordance between the two kinds of methods; 2) specificity of echocardiokimography; 3) advantage in using both methods, specially with MIBI scintigraphy.


Subject(s)
Echocardiography , Electrokymography , Heart Ventricles/physiopathology , Myocardial Infarction/diagnosis , Nitriles , Organotechnetium Compounds , Adult , Aged , Chronic Disease , Female , Humans , Male , Middle Aged , Technetium Tc 99m Sestamibi
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