[Oral antidiabetic therapy and cardiovascular complications: theoretical problem or clinical evidence?].

Theoretical and experimental research data as well as human epidemiological studies on large populations suggest a great difference in influencing cardiovascular processes and alterations among the oral antidiabetic drugs used in the treatment of type II diabetes mellitus. Drugs delaying or inhibiting carbohydrate absorption as well as insulin sensitizers have an unambiguous reducing effect on diabetic cardiovascular complications. Only fluid retention needs precaution during the treatment with thiazolidinedions in patients suffering from heart disease.

Haemodynamic and metabolic effects of low daily dose sulphonylureas in diabetic dog hearts.

The effects of glibenclamide (GB, CAS 10238-21-8) and those of the latest low daily dose sulphonylurea compound, glimepiride (GM, CAS 93479-97-1) on myocardial haemodynamics and pyruvate-lactate metabolism of healthy and alloxan-diabetic dogs (n = 6 in six groups) were compared. Mean arterial blood pressure, heart rate, blood flow of the left anterior descending coronary artery, myocardial contractile force, the rate of change of myocardial contraction and relaxation were measured and arterial (a. carotis communis) and venous (sinus coronarius) pyruvate and lactate concentrations were determined during i.

Influence of diabetic state and that of different sulfonylureas on the size of myocardial infarction with and without ischemic preconditioning in rabbits.

The sensitivity of the myocardium to ischemia and the level of protection achieved by ischemic preconditioning is shaped by the joint influence of several mechanisms in diabetes mellitus. In vivo studies were made in alloxan diabetic and non-diabetic control rabbits to assess if the effects of preconditioning and sulfonylurea pretreatment with either glibenclamide or glimepiride (0.05-0.

The diabetic heart: A review of the lifework of Sophie Maria Koltai.

It is well known that cardiovascular alterations are the principal causes of mortality in patients with diabetes. Premature and accelerated atherosclerosis cannot be the sole cause of diabetic heart disease because functional disorders develop both in experimental and in clinical diabetes before the onset of the detectable morphological changes of the vessel wall. Namely, altered adrenergic responses and prostaglandin metabolism and diminished vasodilatory ability can be seen in diabetic vessels.

Metabolic energy metabolism in diabetes: therapeutic implications.

Diabetic alterations of myocardial metabolism result mainly from malfunctions of acetyl-coenzyme A carboxylase, carnitine-palmitoyl-transferase-I and pyruvate-dehydrogenase inducing an overshoot of fatty acid oxidation that inhibits glucose oxidation. Gene expression of pyruvate-dehydrogenase and glucose transporters and depression of the third step of the mitochondrial respiratory chain also contribute to the diabetic alterations of myocardial metabolism. Ischaemic cardiovascular alterations are common and treatment is rarely successful in cases of diabetes since fatty acid oxidation is the costliest metabolic pathway for oxygen.

Hyperglycaemia alters the endothelium-dependent relaxation of canine coronary arteries.

The aim of the present study was to investigate the effects of experimental diabetes and hyperglycaemia per se on the endothelium-dependent relaxation of isolated canine coronary arteries and to analyse the possible involvement of the cyclooxygenase pathway in the alterations induced by hyperglycaemia. Rings from the left anterior descending coronary arteries of 18 metabolically healthy, six alloxan-diabetic and six insulin-treated alloxan diabetic dogs were set up for isometric tension recording. Diabetic coronaries as well as healthy vessels subjected to in vitro hyperglycaemia (25.

[From type 2 diabetes to metabolic X syndrome].

The more and more exact and simple determination of insulin provides an opportunity for exploration of the states of insulin resistance. It turned out hereby that the so-called type 1 diabetes is merely a consequence of insulin deficiency and it occurs mainly in the young. In contrary, the so-called type 2 diabetes is a multifactorial, often hyperinsulinaemic condition of insulin resistance and it occurs mainly in the adults.

[New concepts in the therapy of diabetic cardiopathies].

Most reasonable cause of diabetic cardiopathy might be the impaired energy fuel supply and metabolism producing inevitably a hypotic condition and needing myocardial cytoprotection. Under diabetic conditions glucose disposal of the heart muscle-decreases, but working myocardial cell remains penetrable for glucose even in the absence of insulin. Therefore, it is worth to stimulate aerobic glycolysis to protect diabetic heart from frequent ischaemic events induced by diabetic late complications, since fatty acids oxidation wastes more oxygen than glycolysis for ATP production.

Characteristics of coronary endothelial dysfunction in experimental diabetes.

Objective: To study the influence of diabetes on the endothelium-dependent vasodilation in the coronary arterial bed.

Methods: The effects of acetylcholine (ACh 2-36 pmol.kg-1; 18 nmol.

Role of vascular adrenergic mechanisms in the haemodynamic and PGI2 stimulating effects of angiotensin in diabetic dogs.

In aware of the well-known altered vascular responsiveness in the diabetic vasculature, this study aimed to compare the haemodynamic and PGI2 releasing effects of angiotensin in metabolically healthy (12) and alloxan-(560 umol/kg) diabetic (12) dogs as well as to analyze the role of vascular adrenoceptors in this. In vivo the effect of intracoronarially administered angiotensin (63-125-250-500-1000 pmol/kg/min) on coronary blood flow, mean arterial blood pressure, myocardial contractile force and heart rate was investigated without and with pretreatment of 2 umol/kg phentolamine. In vitro PGI2 release by isolated coronary rings was induced by 50 nmol/l angiotensin before and after pretreatment with 5 umol/l phentolamine and measured by radioimmunoassay.

What kind of cardiovascular alterations could be influenced positively by oral antidiabetic agents?

Since the first publication of the University Group Diabetes Programme in 1970 the possible deleterious cardiovascular effects of certain hypoglycaemic sulphonylurea products has been well known. In contrast, international knowledge of the advantageous cardiovascular effects of certain sulphonylurea compounds became available recently. Glibenclamide decreases the incidence of fatal myocardial infarction and the development of ventricular fibrillation in patients suffering from acute myocardial infarction.

Comparison of the vasodilatory effects of bradykinin in isolated dog renal arteries and in buffer-perfused dog kidneys.

This study was undertaken to investigate the role of nitric oxide (NO), cyclooxygenase products and bradykinin (Bk) receptors in the Bk evoked responses of canine renal arteries and perfused kidneys. Rings of isolated canine renal arteries were mounted in organ chambers for measurement of isometric force. The isolated canine kidneys were perfused with Krebs-solution (constant flow) and the perfusion pressure was continuously recorded.

Potassium channels in the cardiovascular system.

In vitro and in vivo studies suggest that opening of ATP-sensitive potassium channels following ischaemia enhances recovery of myocardial contraction, dilates blood vessels and has an antiarrhythmic effect. Different sulphonylurea compounds that block the ATP-sensitive potassium channels exert different effects on cardiac functions. Glibenclamide decrease, arrhythmogenesis during acute myocardial infarction in rats and reduces strophanthin cardiotoxicity in rabbits.

Captopril produces endothelium-dependent relaxation of dog isolated renal arteries. Potential role of bradykinin.

The effects of the angiotensin-converting enzyme inhibitors, captopril, lisinopril and enalapril-maleate (the latter being a prodrug that has to be converted into enalaprilat), and bradykinin were investigated in the presence or absence of indomethacin and bradykinin receptor antagonists in dog renal arterial rings precontracted with either prostaglandin F2 alpha or phenylephrine. At a high precontraction level (10 microM of prostaglandin F2 alpha), captopril did not relax the arteries. However, when the tension was low (0.

[Pen-type insulin dispenser for intensive insulin therapy].

The authors investigate the advantage of the intensified insulin therapy and the use of pen-type devices in the practice of the Diabetic Outpatient Clinic of National Institute of Cardiology. The metabolic control improved markedly during intensified insulin therapy already after a short time as three months without any change in the applied dosage. Furthermore pen-type devices have been recognized to let the patients better accept the daily more than two injections, to improve the life-style, and last but not least to decrease the waste quantity of insulin.

Disturbed lipid metabolism in diabetic coronary vessels.

The aim of this study was to clarify whether or not arachidonic acid metabolic disorders are caused by a substrate inavailability and whether such disorders might contribute to circulatory disturbances in the diabetic myocardium. Norepinephrine induced a decrease in the conductivity of both coronary arterial bed and myocardial microcirculation in alloxan-diabetic dogs. It was markedly (p less than 0.

Effect of glimepiride on the electrical activity of isolated rabbit heart muscle.

The effect of glimepiride (CAS 93479-97-1) on the electrical threshold, conduction time, effective refractory period and automaticity of left atrium and right ventricle in the isolated rabbit heart was investigated and compared with those of chlorpropamide and glibenclamide. From the sulphonylureas investigated only glibenclamide diminished the electrical activity of rabbit heart muscle preparations. Chlorpropamide and glimepiride have a mild effect to change the basic parameters on the opposite direction.

[Diabetic cardiopathy. Pathophysiologic concepts and therapeutic approaches].

Epidemiological data reviewed suggest that diabetes itself increases the cardiac risk of diabetics (types I and II), independently from the development of coronary heart disease and in addition to other risk factors (hypertension, hypercholesterolemia, hypertriglyceridemia, smoking and others), presumably by a specific myocardial disease called "diabetic cardiopathy", or according to the recommendations of the WHO, "diabetic heart muscle disease." Disturbances of the left and right ventricular function as well as the autonomic function of the heart can be understood as signs of this specific cardiopathy. The pathophysiological mechanisms underlying this disease are not yet fully known; however, recent evidence is presented that diabetes leads to a facet of metabolic dysfunctions regarding glucose and energy metabolism, calcium homeostasis and the expression of specific proteins that diminish the ability of the heart to respond to increased workload and increase the vulnerability of the heart in diabetes.

The effect of sulphonylurea therapy on the outcome of coronary heart diseases in diabetic patients.

A retrospective study was performed on 1040 diabetic patients. The survival time of those treated with first generation sulphonylureas (n = 227) was considerably (P < 0.001) shorter after the first attack of angina pectoris (5 +/- 1 years, mean +/- S.

[Amidaron-induced dermatopathy resulting from unnecessary Cordarone therapy of ventricular parasystole].

The case history of a patient is reported who was treated with a variety of antiarrhythmics over a period of years because of refractory ventricular "bigeminy". As the arrhythmia did not respond to any kind of therapy, amiodarone treatment was started, which the patient received in a maintenance dose of 600-400 mg/day for 4 years. More recently, a bluish-grey hyperpigmentation of the face and other areas of the skin exposed to sunlight developed.

[Prospective study of cardiac autonomic neuropathy in diabetes mellitus].

For assessment of clinical and prognostic values of cardiac autonomic neuropathy, 53 patients with diabetes mellitus were followed-up for five years. Parasympathetic innervation was assessed by recording heart rate variability during deep breathing, Valsalva manoeuvre and lying-to-standing while sympathetic function was evaluated by measuring postural change in systolic blood pressure. During the follow-up period 1 of 23 diabetic patients died in group without signs of cardiac autonomic neuropathy whereas 2 of 13 diabetics and 10 of 17 diabetics deceased in groups with mild and definitive signs of cardiac autonomic neuropathy, respectively.

Is malondialdehyde a marker of the effect of oxygen free radicals in rat heart tissue?

We tested the effect of exogenous purine derived free radicals and H2O2 vs ischemia and reperfusion on the thiobarbituric-acid (TBA)-reactive material and malondialdehyde (MDA) formation in isolated rat hearts using the thiobarbituric acid test and high performance lipid chromatography (HPLC). We could not detect increased thiobarbituric-acid-reactive material or MDA production during 6 mM H2O2 infusion, during free radical generation by purine-derived free radicals, or using ischemia and reperfusion. Increased thiobarbituric-acid-reactive material and MDA tissue levels were detected only during infusion of 12 mM H2O2 (p less than 0.

Correlation between oesophageal dysmotility and cardiovascular autonomic dysfunction in diabetic patients without gastrointestinal symptoms of autonomic neuropathy.

The vagal function was assessed by oesophageal scintigraphy and cardiovascular autonomic function tests in 65 diabetic patients without gastrointestinal symptoms of autonomic neuropathy and in 20 control subjects. Oesophageal radioisotope transit time was abnormal in 32% of diabetics. Values of cardiovascular function tests were normal in 34% of diabetics while definitive and early signs of cardiac autonomic neuropathy were found in 34% and 32% of diabetics, respectively.

Cardiac autonomic neuropathy and QT interval length. A follow-up study in diabetic patients.

For evaluating the clinical significance of QT interval prolongation in diabetics with cardiac autonomic neuropathy (CAN), 53 diabetic patients were followed-up for 5 years or to death and the results of cardiovascular function tests as well as the values of QT intervals were repeatedly determined. At baseline investigation, the QTc intervals were significantly longer in diabetics with definitive (456 +/- 5 ms, mean +/- SEM, n = 17) than those with early (435 +/- 5 ms, n = 13, p less than 0.01) and without (413 +/- 4 ms, n = 23, p less than 0.