Effect of long-term treatment with insulin and/or acarbose on glomerular basement membrane thickening in alloxan-diabetic rats

Acarbose is a competitive inhibitor of the intestinal alpha-glycosidases, that can delay absorption of intestinal carbohydrates causing their malabsorption. In the present paper we studied the effects of insulin, acarbose and their association on glomerular basement membrane thickening in alloxan-diabetic rats. Twenty-five male and female Wistar rats, approximately 3 months old at the beginning of the experiment, were assigned randomly to each of five experimental groups: normal control rats, alloxan-diabetic control rats, alloxan-diabetic rats treated with acarbose, alloxan-diabetic rats treated with insulin, and aloxan-diabetic rats treated with insulin plus acarbose. Alloxan was administered in a single iv dose of 42 mg/kg body weight. Insulin was given subcutaneously at doses of 18 to 30 IU/kg corrected daily on the basis of glycosuria and ketonuria. Acarbose was given mixed with rat chow in a dose of 50 mg/100 g chow. Body weight, water and food intake and diuresis, as well as blood and urine glucose were determined after 1, 3, 6, 9, and 12 months of treatment. Glomerular basement membrane (GBM) thickening was determined by electron microscopy at the same times. Clear clinical and laboratory signs of severe diabetes, with blood glucose levels above 200 mg/dl and urine glucose above 3000 mg/dl, were observed in all alloxan-diabetic control rats, in all periods of follow-up, whereas administration of insulin or acarbose reduced the blood glucose levels of treated groups. The most satisfactory control of blood and urine glucose was observed in animals treated with both insulin and acarbose. However, diarrhea was observed in diabetic rats treated with acarbose associated or not with insulin, GBM thickening was correlated with age in all groups. Beginning at six months after diabetes induction, the GBM of untreated diabetic rats was significantly thicker (mean + 4.446 + 0.45 mm) than that of normal rats (2.977 + 0.63 mm). Both insulin and acarbose prevented GBM thickening and their combination induced thickening similar to the age-dependent thickening observed for normal rats of the same age. We conclude that acarbose when combined with insulin may be a good option in the control of diabetes and its renal complications.

Central hemodynamic effects of diuretic therapy in chronic heart failure.

In chronic heart failure diuretic drugs improve central hemodynamic variables and cardiac pumping secondary to altered plasma and extracellular volumes; humoral markers of these changes include increased plasma renin and aldosterone levels. The latter increases are maximal over the first week but decline with chronic therapy. The plasma alpha-ANP levels show a reciprocal effect; these data are compatible with a rapid contraction of the plasma volume which is sustained during chronic therapy. The acute hemodynamic actions of diuretic agents reflect both immediate and direct vascular actions and also effects secondary to diuresis (volume redistribution). At rest substantial reductions in pulmonary "wedge" pressure (-29%), with a consequent fall in cardiac output (-10%), are described. Total systemic vascular resistance initially increases but "reverse autoregulation" over subsequent weeks returns this elevation gradually towards control values. Tolerance to these initial hemodynamic effects does not occur with maintained therapy; moreover, echocardiographic markers of contractility and exercise capacity may increase. The early venodilator effects of diuretic drugs can be attributed to prostaglandin release and the initial pressor actions to activation of the renin angiotensin system; these vascular actions may have limited relevance to long-term beneficial effects on hemodynamics. Direct pulmonary vasodilation and improved pulmonary compliance remain an interesting finding. Although most patients are both symptomatically and hemodynamically improved at rest, the actions during exercise are more varied. Some individuals with severely impaired left ventricular function show little hemodynamic improvement, whereas those with milder dysfunction usually benefit; in the main this is probably related to the latter being on a steeper cardiac function curve.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term treatment of essential arterial hypertension with nitrendipine.

The efficacy and safety of long-term treatment with oral nitrendipine were evaluated in 34 patients with essential arterial hypertension. Nitrendipine alone significantly lowered systolic and diastolic blood pressure levels in 28 patients who completed the preliminary four-week dose-setting phase. Twenty-one patients completed the one-year treatment. Blood pressure control was maintained by nitrendipine alone in 11 patients. Ten patients not adequately controlled at the end of the dose-setting phase were successfully treated with nitrendipine combined with acebutolol or muzolimine. It is concluded that nitrendipine is a promising calcium antagonist for the treatment of arterial hypertension.

Metabolic effects of long-term therapy with muzolimine and chlorthalidone in hypertension.

Previous short-term studies of muzolimine (a diuretic with frusemide-like activity) had shown that it did not induce a significant change in the serum potassium concentration. In the present study sodium and potassium handling and other metabolic variables have been compared during 16 weeks of therapy with muzolimine and chlorthalidone, a thiazide-like diuretic. During muzolimine treatment, plasma and red cell potassium concentrations remained unchanged, while a significant fall in potassium occurred with chlorthalidone. Neither drug affected the activity of sodium-potassium cotransport or sodium-lithium countertransport in red cells in vitro. Muzolimine and chlorthalidone had similar effects on arterial pressure and on the other metabolic variables tested.

Clinical trial with muzolimine in healthy and hypertensive subjects: new vistas on the drug action.

The mechanism of muzolimine (3-amino-1-[3,4-dichloro-alpha-methyl-benzyl]-2 pyrazolin-5-one) action is still not completely defined. The identified site of action is the Henle loop, similarly to furosemide which acts also by mediating renal prostaglandin synthesis. The aim of the present study was to evaluate the early effects of muzolimine (30 mg per os) on renal function and prostaglandin urinary excretion in healthy controls and hypertensive subjects. Urinary flow reached the peak values by the third hour after the drug and a diuretic effect not directly dependent on glomerular filtration was observed, especially in hypertensive patients. In these cases the diuresis increased also due to a low glomerular filtration rate and tubular phenomena were more evident than in controls: an increasing Na+ tubular excretion and a parallel decreasing % Na+ reabsorption. Blood pressure was not significantly influenced by muzolimine in healthy subjects, while it returned to normal values in the hypertensive group. A cyclooxigenase inhibitor, lysine acetylsalicylate (1 g i.m.) administered 10 minutes after muzolimine, was not able to modify the parameters under consideration. Therefore a mediation by prostaglandins on the diuretic and antihypertensive effects of the drug under study may probably be excluded.

[Clinical and hemodynamic effects of medium-term treatment with muzolimine in subjects with essential arterial hypertension]. / Effetti clinici ed emodinamici del trattamento a medio termine con muzolimina in soggetti con ipertensione arteriosa essenziale.

The antihypertensive effects and haemodynamic changes after administration of 30 mg/die of muzolimine for 30 days in a group of patients with mild or moderate essential hypertension have been evaluated. Our findings showed a significant reduction of body weight, arterial blood pressure, systemic vascular resistance, plasma volume and small but significant increase of left ventricular ejection fraction. No relevant side effect have been observed.

Effects of a new loop diuretic (muzolimine) in cirrhosis with ascites: comparison with furosemide.

Muzolimine is a loop diuretic with both the dose-dependent increasing effectiveness of loop diuretics and the long-lasting effect of thiazides. This is a potential advantage in the treatment of ascites in advanced cirrhosis since these patients have a low tolerance to sudden reductions of blood volume. Equivalent single, oral doses of furosemide (40 mg) and muzolimine (30 mg) were given to 10 cirrhotic patients with ascites and reduced renal perfusion (glomerular filtration rate = 30 to 75 ml per min). The study was preceded by 4 days of equilibration (dietary sodium 40 mmoles per day), and the drugs were alternated via a single-blind, cross-over protocol after a wash-out period of 3 days. Renal function was monitored under basal conditions and after diuretic administration through 4-hr clearance periods for 24 hr. The renin-aldosterone axis was evaluated before diuretic administration and after 8 and 24 hr. Muzolimine led to a 12-hr cumulative diuresis [AUC0-12 = 2.52 +/- 0.42 (S.E.) ml per min] and natriuresis (5.14 +/- 1.05 mmoles per hr), which were comparable to those of furosemide (2.85 +/- 0.29 ml per min and 6.75 +/- 1.63 mmoles per hr). Its effect, however, was distributed over a longer period (8 hr) than furosemide (4 hr). Muzolimine activity mainly differed from furosemide because of: significantly lower 12-hr potassium excretion (AUC0-12 = 0.28 +/- 0.82 vs. 2.69 +/- 0.46 mmoles per hr; p less than 0.005); greater sodium/chloride excretion ratio (0.45 +/- 0.08 vs. 0.26 +/- 0.06; p less than 0.025), and absence of rebound phenomena.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the effects of muzolimine and a fixed combination of diuretics in essential hypertension.

The efficacy and tolerance of the loop diuretic muzolimine were compared with those of a fixed combination of hydrochlorothiazide and amiloride in patients with mild to moderate hypertension. After a placebo lead-in period, patients whose supine diastolic blood pressure was between 90 and 115 mm Hg were randomly allocated either to muzolimine, 20 mg/day, or to hydrochlorothiazide, 50 mg/day, and amiloride, 5 mg/day. The mean duration of follow-up was 4.7 months in both groups. Both muzolimine and the combination significantly decreased the mean blood pressure. The two treatments were similar in efficacy. The incidence of side effects during the trial was similar with both treatments, and no serious adverse reactions occurred. Eleven subjects in the muzolimine group were entered into an open long-term study. In all these subjects the blood pressure remained adequately controlled throughout the 4 to 6 months of additional follow-up and no side effects were reported. Muzolimine appears to be an effective and safe antihypertensive agent.

Captopril in mild heart failure: preliminary observations of a long-term, double-blind, placebo-controlled multicentre trial.

Ninety-four patients on digitalis treatment for chronic congestive heart failure (NYHA class II-III) were enrolled for a 12 month trial in a random, double-blind, placebo-controlled study. After a placebo run-in period, patients were assigned to placebo or captopril 25 mg t.i.d. Digitalis was continued while diuretics were withdrawn. Clinical status, exercise capacity, cardiac dimensions and performance were evaluated with a full physical examination, 12 lead ECG, chest X-ray, 24 hour Holter monitoring, bicycle effort capacity, M-mode echocardiography and radionuclide ventriculography at 1, 2 and 3 weeks and 1, 2, 3, 6 and 12 months. There were no significant differences in the trend of survival curves after six months follow-up between the captopril or placebo treatment groups. Patients treated with captopril, without the addition of diuretics, had an improvement in NYHA class (P less than 0.01), an increase in exercise capacity (P less than 0.025), a decrease in cardiothoracic ratio (P less than 0.025) and an increase of echocardiographic left ventricular contractility (P less than 0.005). Only four patients treated with captopril were withdrawn from the follow-up for allergic side effects. Preliminary results at 6 months prove that captopril, compared to placebo, is useful in mild to moderate heart failure.

Comparative pharmacodynamics of furosemide and muzolimine in cirrhosis. Study on renal sodium and potassium handling and renin-aldosterone axis.

Ten male cirrhotic patients with ascites and reduced renal function were randomly given equivalent doses of furosemide and muzolimine by the oral route, through a single blind cross-over protocol. Renal function, electrolyte plasma concentrations and urinary excretions and renin-angiotensin-aldosterone system components were evaluated under basal conditions and after drug administration. The diuretic and saluretic effects being equal, the response to muzolimine was initially weaker but more prolonged than to furosemide, without rebound phenomena. The furosemide-induced natriuresis was in part related to the filtered sodium load, whereas muzolimine natriuresis was only correlated to the inhibition of tubular sodium reabsorption. No potassium wasting effect was seen after muzolimine administration. Transient plasma potassium concentration reduction observed during muzolimine suggests an ion shift within the intracellular compartment. Therefore, a possible interaction of the drug with cellular sodium active transport systems can be hypothesized. A significant increase of plasma renin activity was observed after furosemide. No significant changes were seen after muzolimine administration.

Comparative study of muzolimine and acebutolol in the treatment of moderate hypertension.

In a controlled double-blind study the effect of muzolimine (20 mg o.d.) and acebutolol (400 mg o.d.) were investigated in outpatients suffering from moderate essential hypertension. After a three week placebo run-in period, 49 patients were recruited and followed by a cooperative group of general practitioners over a period of 3 months. Blood pressure decreased to the same extent in both groups. With regard to clinical and biological tolerance, no differences appeared between the two drugs.

Interference on metabolism induced by muzolimine and chlorthalidone in type II hypertensive diabetics.

There is a very high prevalence of hypertension in diabetic subjects, which makes it necessary to use an antihypertensive drug with the least possible metabolic interference. For example, in the early phase of hypertension, diuretics usually worsen the metabolic equilibrium. According to recent reports, a new diuretic, muzolimine (MZ), which acts on the loop of Henle, seems to present a minor effect on carbohydrate metabolic balance. In order to determine whether this assumption was correct or not, we carried out a clinical trial on 26 type II (non-insulin-dependent) diabetics, in fairly good metabolic control and with moderate hypertension (orthostatic diastolic pressure from 100 to 115 mmHg), comparing the effect of MZ with those of chlorthalidone (CL). According to a randomized, single-blind cross-over design, the patients were treated with MZ (20 mg/day) or CL (50 mg/day) for the duration of 4 weeks. After the treatment period with the first drug, there was a 2 week wash-out period on placebo (PL) before the second drug was given. During the study, a set of metabolic and non-metabolic parameters was monitored, as were the clinostatic and orthostatic blood pressure values. The results show that the antihypertensive effect of the two drugs was the same (both caused a more than 10% decrease in systolic and diastolic blood pressure). No significant changes in plasma electrolyte levels occurred. There was a significant (p less than 0.05) increase in urinary aldosterone excretion after CL (20.7 +/- 11 micrograms/24 hours vs. 13.3 +/- 8.5 after PL, and 14.5 +/- 7.2 after MZ) (mean values +/- standard deviations).(ABSTRACT TRUNCATED AT 250 WORDS)

Cross-over study of muzolimine and hydrochlorothiazide-amiloride in hypertensive patients.

Thiazide therapy is a widely used first line treatment for arterial hypertension. Its useful value, particularly in mild or moderate hypertension, is sometimes reduced by metabolic side-effects, as hypokalaemia and hyperuricaemia. In the present study the antihypertensive efficacy of a new, non-sulphonamide diuretic Bay g 2821 (muzolimine) was evaluated in comparison with the combination of hydrochlorothiazide-amiloride over a period of 4 weeks. A highly significant decrease in systolic and diastolic blood pressures was produced by both treatments. No decrease in serum potassium nor an increase in cholesterol, triglycerides, uric acid or glucose was detected during the 4 week treatment period. Subjective side-effects, such as headache and dizziness, were very rarely observed during Bay g 2821 treatment. The new diuretic appears, therefore, to be effective in the treatment of arterial hypertension without untoward side-effects.

Effects of muzolimine and of a combination of hydrochlorothiazide/triamterene in healthy subjects and in nephrotic patients.

The diuretic effects of 30 mg muzolimine and 25 mg hydrochlorothiazide/50 mg triamterene were comparable in healthy subjects and nephrotic patients (serum albumin less than 32 g/l, creatinine clearance greater than 50 ml/min/1.73 m2). A single daily dose of 30 mg muzolimine or 25 mg hydrochlorothiazide/50 mg triamterene was sufficient in the majority of the investigated nephrotic patients. The different diuretic effects which were observed in nephrotic patients were not related to the severity of hypalbuminemia, but rather to differences in preceding diuretic treatment. Plasma levels and urinary excretion of unchanged muzolimine were comparable in healthy subjects and nephrotic patients after one day of diuretic treatment; after seven days of treatment plasma levels of muzolimine were significantly lower and urinary excretion significantly higher in nephrotic patients than in control subjects.

Muzolimine in advanced chronic renal failure.

27 patients with creatinine clearances ranging from 20 to 2 ml/min were treated daily with 6.9 mg/kg of muzolimine, for 10 to 25 days. The hyperhydration state with oedema decreased gradually in all patients without hypotensive phenomena. Muzolimine benefited hypertension in patients with expansion of the extracellular space and it also strengthened the effect of clonidine or minoxidil. Important diuretic and natriuretic effects were obtained. Metabolic acidosis improved. No subjective adverse reactions to the drug or side effects were noted. High-dose muzolimine appears to be efficacious and safe for short-term treatment in patients with severe chronic renal failure.

Step-dose of muzolimine at different stages of chronic renal failure: comparison with furosemide.

The authors have compared the clinical and metabolic effects of two high ceiling diuretics, muzolimine (M) and furosemide (F), by i.v. and oral routes in 40 patients classified in four groups with different degrees of renal failure. The study demonstrated a more pronounced effectiveness of M than F by oral administration, while it appeared equal to F when given i.v. The urine volume and Na+ excretion were significantly increased during M treatment compared to oral F in each group. Calcium urinary excretion was reduced with M while P was increased compared with F. BUN, creatinine and uric acid were temporarily increased in the 3rd and 4th groups, probably due to extracellular fluid volume contraction, associated also with transient change in GFR. M at a lower dosage than F has demonstrated an effective diuretic response irrespective the degree of renal impairment. From its pharmacological properties, M appears a safe and active diuretic agent, particularly at a high dosage in patients with severe renal failure, and is notable for its lack of important side effects.