Diabetes Mellitus and Hypertension, Emerging Therapeutic Perspectives

Effects of telmisartan compared with eprosartan on blood pressure control, glucose metabolism and lipid profile in hypertensive, type 2 diabetic patients: a randomized, double-blind, placebo-controlled 12-month study

We evaluated the antihypertensive activity, glucose homeostasis and plasma lipid profile in patients with mild hypertension and type 2 diabetes mellitus treated by diet and exercise, and not in receipt of oral hyperglycemics, following 12-month treatment with either telmisartan or eprosartan. In this double-blind, placebo-controlled trial, 119 patients with mild essential hypertension (diastolic blood pressure [DBP] 91-104 mmHg) and type 2 diabetes were divided into three groups and randomized to receive once-daily telmisartan 40 mg, eprosartan 600 mg, or placebo for 12 months. At enrollment, patients were advised on diet (1,400-1,600 kcal/day) and exercise (physical aerobics on a bicycle for at least 30 min on 4 days each week). Compared with baseline, a significant reduction (p<0.01) in seated trough systolic blood pressure (SBP) was detected after 12-month treatment with either telmisartan or eprosartan. Seated trough DBP was also reduced by telmisartan (p<0.01) and eprosartan (p<0.05); the antihypertensive effect of telmisartan was significantly superior (p<0.05). No change in body mass index or glucose metabolism was observed with either active treatment, or with placebo. Telmisartan, but not eprosartan, significantly improved plasma total cholesterol (p<0.01), low-density lipoprotein cholesterol (p<0.01) and triglycerides (p<0.05) compared with eprosartan. In conclusion, 12-month telmisartan treatment produced a significantly greater reduction in DBP than eprosartan and significantly improved plasma lipids. The improvement could be due to varying pharmacokinetic/pharmacodynamic properties of telmisartan compared with eprosartan, even if it is not clear about the relationship between angiotensin-II receptor blockade and 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibition.

Comparison of the effects of telmisartan and nifedipine gastrointestinal therapeutic system on blood pressure control, glucose metabolism, and the lipid profile in patients with type 2 diabetes mellitus and mild hypertension: a 12-month, randomized, double-blind study

BACKGROUND

Angiotensin receptor blockers (ARBs) provide effective blood pressure control. Whereas none of the ARBs appear to affect glucose homeostasis, some ARBs have been associated with a decrease in cholesterolemia.

OBJECTIVE

This study was conducted to evaluate blood pressure control glucose homeostasis, and the plasma lipid profile in patients with type 2 diabetes mellitus and mild hypertension during 12 months of treatment with the ARB telmisartan or nifedipine gastrointestinal therapeutic system (GITS).

METHODS

In this double-blind trial, patients taking oral hypoglycemic agents were randomized to receive telmisartan 40 mg or nifedipine GITS 20 mg once daily for 12 months. At the time of enrollment, patients were given advice on diet (1400-1600 kcal/d) and exercise (stationary bicycle for > or =30 min, 4 d/wk). Assessments of systolic blood pressure (SBP), diastolic blood pressure, body mass index (BMI), fasting plasma glucose concentrations, glycosylated hemoglobin, fasting plasma insulin concentrations, the homeostasis model assessment of insulin resistance, and the lipid profile were performed at baseline and after 6 and 12 months of treatment.

RESULTS

One hundred sixteen patients were divided into 2 age- and sex-matched treatment groups (58 men, 58 women; mean [SD] age, 52.5 [5] years). All patients were in good general health at baseline; had achieved adequate glycemic control with diet and oral hypoglycemic agents; were taking antihypercholesterolemic drugs; and had no evidence of macroangiopathy, microalbuminuria, or neuropathy. There were significant reductions from baseline in seated trough SBP after 12 months of treatment with both telmisartan and nifedipine GITS (from 139 [4] to 132 [4] mm Hg and from 140 [4] to 130 [4] mm Hg, respectively; both, P < 0.01). No change in BMI or glucose metabolism was observed with either treatment. After 12 months, there were significant improvements in concentrations of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) with telmisartan (-9% and -11.5%, respectively; both, P < 0.01) compared with nifedipine GITS (-2% and -1.5%).

CONCLUSIONS

In this selected sample of patients with type 2 diabetes and mild hypertension, both telmisartan and nifedipine GITS produced significant reductions in blood pressure. Telmisartan was associated with a slight but statistically significant improvement in plasma TC and LDL-C concentrations compared with nifedipine GITS.

A randomized, double-blind, controlled, parallel-group comparison of perindopril and candesartan in hypertensive patients with type 2 diabetes mellitus

BACKGROUND

When choosing an antihypertensive drug for patients with hypertension and diabetes mellitus (DM), the metabolic side effects, possibility of improving some metabolic parameters, and need for adequate blood pressure control must all be considered.

OBJECTIVE

The goal of this study was to compare the impacts of perindopril and candesartan on blood pressure, glucose metabolism, serum lipid profile, and metabolic parameters in patients with mild hypertension and type 2 DM during therapy and after a 1-month washout period.

METHODS

Type 2 DM patients with mild hypertension and good glucose control who were not taking hypercholesterolemic drugs were enrolled. Perindopril 4 mg QD or candesartan 16 mg QD was administered for 12 months in this randomized, double-blind, controlled, parallel-group clinical trial. Fasting plasma glucose (FPG), fasting plasma insulin (FPI), glycosylated hemoglobin, homeostasis model assessment (HOMA) index, systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, triglycerides, lipoprotein(a) (Lp[a]), plasminogen activator inhibitor 1 (PAI-1), homocysteine, body mass index (BMI), and albumin excretion rate (AER) were assessed.

RESULTS

Ninety-six patients (49 women and 47 men; mean [SD] ages, 53 [10] years [perindopril] and 55 [9] years [candesartan]) were enrolled. Mean (SD) body weight, height, and BMI were 78.2 (9.4) kg, 1.69 (0.05) m, and 27.2 (2.0) kg/m(2) in the perindopril group and 77.5 (8.6) kg, 1.70 (0.06) m, and 26.8 (2.5) kg/m(2) in the candesartan group. A significant change occurred from baseline to month 12 during treatment with perindopril in SBP and DBP (both P < 0.01), FPG (P < 0.05), FPI (P < 0.05), TC (P < 0.05), LDL-C (P < 0.05), Lp(a) (P < 0.05), PAM (P < 0.05), and AER (P < 0.05). Significant changes from baseline to month 12 occurred with candesartan in SBP and DBP (both P < 0.01) and AER (P < 0.05). The HOMA index was significantly lower at month 12 in the perindopril group than in the candesartan group (P < 0.05). When we interrupted perindopril and candesartan therapy for a 1-month washout period, changes in SBP and DBP values were significant compared with month 12 in both groups (all P < 0.05). Changes in TC and LDL-C from month 12 to the end of washout were significant only in the perindopril group (both P < 0.05).

CONCLUSIONS

Perindopril and candesartan both effectively lowered blood pressure in this group of patients with mild hypertension and type 2 DM. Perindopril showed an improvement on some metabolic parameters compared with candesartan. However, the inclusion/exclusion criteria could limit the ability to extrapolate the results to a general population.

Impairment of afferent arteriolar myogenic responsiveness in the galactose-fed rat is prevented by tolrestat

By permitting the separation of increased aldose reductase activity from hyperglycaemia and insulin deficiency, galactose-fed rats have constituted a useful model for investigating diabetic complications. Such rats manifest an impaired afferent arteriolar responsiveness to pressure similar to that of rats 4 to 6 weeks after induction of diabetes with streptozotocin. In the present study, we investigated whether treatment of galactose-fed rats with the aldose reductase inhibitor tolrestat prevent this autoregulatory defect and whether the blunted afferent arteriolar responsiveness to pressure is associated with impaired responsiveness to angiotensin II. Pressure-induced vasoconstriction of afferent arterioles was assessed in kidneys made hydronephrotic to allow direct visualization of renal microvessels by computer-assisted image processing. Vessel diameters were quantitated following stepwise increments of renal perfusion pressure (RAP; from 80 to 180 mm Hg) in kidneys of control rats and rats fed a diet for 2 weeks with 50% galactose with or without tolrestat. Subsequent to the pressure studies, angiotensin II (0.3 nmol/l) was added to the perfusate, and vessel diameters were reassessed. Control rats exhibited progressive afferent arteriolar vasoconstriction when RAP was increased from 80 to 180 mm Hg (-17.2 +/- 1.0%; p < 0.001). In contrast, myogenic responses to increases in pressure were absent in the arterioles of the galactose-fed rats (-4.1 +/- 1.9%; N.S.). Treatment with tolrestat completely prevented this impairment in afferent arteriolar responsiveness (-16.5 +/- 1.8%; p < 0.001). The angiotensin II-induced vasoconstriction did not differ between control rats and galactose-fed rats. We conclude that increased aldose reductase activity contributes to impaired renal auto-regulation in galactose-fed rats, a model of diabetic nephropathy, but is not involved in the loss of afferent arteriolar responsiveness to angiotensin II.