Efficacy and safety of the dual L- and T-type calcium channel blocker, ACT-280778: a proof-of-concept study in patients with mild-to-moderate essential hypertension.

ACT-280778 is an oral, non-dihydropyridine, dual L-/T-type calcium channel blocker. This phase 2a, double-blind, randomized, placebo- and active-controlled study investigated the efficacy and safety of 10 mg ACT-280778. Patients with mild-to-moderate essential hypertension received once-daily placebo (n=53), ACT-280778 10 mg (n=52) or amlodipine 10 mg (n=54) for 4 weeks. The primary end point was the change from baseline to week 4 in placebo-adjusted mean trough sitting diastolic blood pressure (SiDBP) with ACT-280778. Tolerability was assessed by recording treatment-emergent adverse events (TEAEs). Baseline clinical characteristics were similar across groups. No significant difference was observed at week 4 in mean trough SiDBP between placebo (-9.9 (95% confidence limit (CL) -12.7, -7.0) mm Hg) and ACT-280778 (-9.5 (-12.4, -6.5) mm Hg; P=0.86); amlodipine reduced mean trough SiDBP by -16.8 (-19.0, -14.5) mm Hg, confirming assay validity. Change in mean PR interval at week 4 (pre-dose) differed between placebo (-1.0 (95% CL -4.4, 2.3) ms) and ACT-280778 (6.5 (3.5, 9.6) ms); amlodipine did not increase PR interval (1.1 (-1.6, 3.9) ms).Treatment-emergent adverse events (TEAE) frequency was 32.1% (placebo), 32.7% (ACT-280778) and 33.3% (amlodipine). The most common TEAEs were headache, peripheral edema, hypertension and second-degree atrioventricular block. ACT-280778 (10 mg) did not lower blood pressure in mild-to-moderate hypertension.

High dose treatment with angiotensin II receptor blocker in patients with hypertension: differential effect of tissue protection versus blood pressure lowering.

Aggressive inhibition of renin-angiotensin-aldosterone system may provide the best cardiovascular protection. We examined the effect of different doses of angiotensin II receptor blocker, Candesartan, on arterial elasticity, inflammatory and metabolic parameters in hypertensive patients with multiple cardiovascular risk factors. 69 hypertensive patients were randomized into three groups: group 1 included patients treated with high doses of Candesartan (32 mg), group 2 included patients treated with conventional doses of Candesartan (16 mg), group 3 included patients that received antihypertensive treatment other that angiotensin II type-1 receptor blockers (ARBs) or angiotensin-converting enzyme inhibitors (ACEIs). Patients were evaluated for lipid profile, HbA1C, insulin, C-peptide, hs-CRP, aldosterone, renin and Homeostasis model assessment-insulin resistance (HOMA-IR). Arterial elasticity was evaluated using pulse wave contour analysis method (HDI CR 2000, Eagan, Minnesota). In patients treated with high doses of Candesartan: large artery elasticity index (LAEI) increased from 8.6+/-2.8 to 16.6+/-5.1 ml/mm Hg x 100 after 6 months of treatment (p<0.0001). Small artery elasticity index (SAEI) increased from 2.7+/-1.3 to 5.9+/-2.8 ml/mm Hg x 100 (p<0.0001). Systemic vascular resistance (SVR) decreased from 1881.5+/-527.5 to 1520.9+/-271.8 (p<0.0006). In patients treated with conventional doses of Candesartan: LAEI index increased from 11.0+/-3.5 to 14.4+/-3.2 ml/mm Hg x 100 (p<0.0001). SAEI increased during the study from 3.7+/-1.4 to 5.4+/-2.1 ml/mm Hg x 100 (p<0.0001). SVR decreased from 1699.8+/-327.6 to 1400.7+/-241 (p<0.0001). In the control group: neither LAE nor SAE improved during the treatment period. Although similar reduction in blood pressure was observed in all three groups, both LAE and SAE improved only in patients treated by ARBs. Treatment with high doses of Candesartan improves arterial stiffness to a greater extent than conventional doses of Candesartan, despite comparable changes in blood pressure.

Effect of long-term treatment with rosiglitazone on arterial elasticity and metabolic parameters in patients with Type 2 diabetes mellitus: a 2-year follow-up study.

AIMS: Thiazolidinediones may influence the atherogenic process by improving cardiovascular risk factors. The present study was designed to determine the long-term effect of rosiglitazone on arterial compliance and metabolic parameters in patients with Type 2 diabetes. METHODS: In an open-label, prospective study, 65 diabetic patients received rosiglitazone orally (4-8 mg/day) for 6 months. After 6 months, the patients continued an open follow-up study and were divided into two groups: group 1 included patients continuing rosiglitazone for 2 years, group 2 included patients discontinuing rosiglitazone and receiving other oral glucose-lowering agents. Lipid profile, glycated haemoglobin (HbA1c), insulin, C-peptide, fibrinogen, high-sensitivity-CRP and homeostasis model assessment-insulin resistance were measured. Arterial elasticity was assessed using pulse wave contour analysis. RESULTS: In patients treated with rosiglitazone for 2 years: the large artery elasticity index (LAEI) increased from 10.0 +/- 4.6 to 13.9 +/- 4.7 ml/mmHg x 100 after 2 years (P = 0.003). The small artery elasticity (SAEI) index increased significantly from 3.2 +/- 1.2 to 5.1 +/- 1.9 (P < 0.0001). In patients who discontinued rosiglitazone: LAEI did not change after 6 months, but decreased from 12.1 +/- 5.4 to 8.9 +/- 3.9 ml/mmHg x 10 (P < 0.0001) at the end of 2 years. SAEI increased during the first 6 months of treatment, from 3.9 +/- 1.8 to 5.1 +/- 1.5 ml/mmHg x 100 (P < 0.0001) and decreased after discontinuation of rosiglitazone (P = 0.042). CONCLUSIONS: Prolonged treatment with rosiglitazone improved arterial elasticity. However, significant deterioration in LAEI and SAEI was observed in patients who discontinued rosiglitazone. The beneficial vascular effect of rosiglitazone on arterial elasticity was independent of glycaemic control.

C-reactive protein distribution and correlates among men and women with chronic coronary heart disease.

BACKGROUND: C-reactive protein (CRP) elevated in inflammation is associated with atherosclerotic disease. We describe the distribution of CRP and its association with coronary heart disease (CHD) risk factors in a large CHD patient group. METHODS: This analysis comprises 2,723 male and 256 female CHD patients, included in the Bezafibrate Infarction Prevention (BIP) study. High sensitive CRP levels were determined in frozen plasma samples. RESULTS: CRP distribution, was normalized upon log transformation. Levels among women were higher than in men in the entire group (4.4 vs. 3.5 mg/l) and in each age group. Co-morbidities, smoking, lower education level, and use of cardiovascular drugs, were associated with elevated CRP levels in both sexes. The correlation between CRP and body mass index (BMI), insulin and glucose was stronger among women. The explained variability in CRP level was larger in women (20%) compared to men (13%). Among women, BMI explained 10% of CRP variability, whereas the contribution of each variable among men was significantly smaller. CONCLUSIONS: Among men and women with CHD, CRP level was correlated with traditional risk factors and to a lesser degree to manifestation of CHD. BMI is the main contributor to CRP variability, explained by these factors among women.

Long-term thyrotropin-suppressive therapy with levothyroxine impairs small and large artery elasticity and increases left ventricular mass in patients with thyroid carcinoma.

BACKGROUND: Exogenous subclinical hyperthyroidism, caused by long-term thyrotropin (TSH)-suppressive treatment with levothyroxine (LT(4)), is associated with several cardiovascular abnormalities. In order to assess the effect of long-term thyroid hormone-suppressive therapy on the blood vessels and myocardium, we determined the arterial elasticity, using the pulse wave contour analysis. METHODS AND RESULTS: Twenty-six athyreotic patients receiving TSH-suppressive LT(4) therapy for periods ranging from 3 to 21 years at a mean daily dose of 2.25 +/- 0.5 microg/kg per day were included in the study. Twenty six age- and gender-matched healthy subjects served as controls. Arterial elasticity of large and small arteries was evaluated using pulse wave contour analysis method (HDI CR 200, Eagen, MN). Cardiac structure was assessed by two-dimensional echocardiography. We found decreased large artery elasticity in subclinical hyperthyroidism (sHT) patients compared to controls (14.14 +/- 3.38 versus 10.53 +/- 2.43 L/mm Hg x 100, p < 0.000). Small artery elasticity was also lower in patients than in controls (5.42 +/- 1.82 versus 4.30 +/- 1.75 mL/mm Hg x 100, p < 0.056). The echocardiographic data showed significantly increased left ventricular (LV) mass index (101.90 +/- 18.61 versus 88.03 +/- 22.01 g/m(2), p < 0.049) and interventricular septum thickness (10.61 +/- 1.46 versus 9.11 +/- 1.13 mm, p < 0.002) in LT(4)-treated patients compared to controls. CONCLUSIONS: We found impaired vascular elasticity of large and small arteries and increased LV mass in patients receiving long-term TSH-suppressive therapy with LT(4).

The effect of a rapid weight loss induced by laparoscopic adjustable gastric banding on arterial stiffness, metabolic and inflammatory parameters in patients with morbid obesity.

OBJECTIVE: To determine the effect of drastic weight loss on arterial compliance, inflammatory and metabolic parameters in patients with morbid obesity with and without cardiovascular risk factors who underwent laparoscopic adjustable gastric banding (LAGB). DESIGN: Open prospective study, morbidly obese subjects divided into low- and high-risk group were evaluated before and 4 months after LAGB. SUBJECTS: Forty-one Caucasian subjects aged between 16 and 55 years, with morbid (grade 3) obesity (20 low- risk and 21 high-risk subjects) who underwent LAGB and completed a 16-week follow-up. MEASUREMENTS: Patients were evaluated at baseline and 4 months after LAGB for body mass index (BMI), arterial blood pressure (BP), metabolic factors including lipid profile, HbA1C, insulin, C-peptide, fibrinogen, hs-C reactive protein (CRP) and Homeostasis model assessment-insulin resistance (HOMA-IR). Arterial elasticity of large and small arteries was evaluated using pulse-wave contour analysis method (HDI CR 2000, Eagan, Minnesota) at baseline and after 4 months. RESULTS: Body mass index reduction induced by LABG, from 43.55+/-5.11 to 35.10+/-4.87 in low-risk patients and from 42.90+/-3.22 to 35.00+/-3.24 in high-risk patients, significantly improved small artery elasticity (SAE) from 6.30+/-2.74 to 7.25+/-1.85, in morbidly obese patients with multiple cardiovascular risk factors (high-risk group). Improvement in SAE was accompanied by improvement of arterial BP, glucose and lipid metabolism, and reduction of CRP values. CONCLUSION: Although dramatic weight reduction induced by surgical intervention was associated with similar changes in body weight and significant improvement of metabolic and inflammatory parameters in two groups of obese patients, SAE improved only in high-risk patients.

Glucagon does not affect catecholamine release in primary cultures of bovine adrenal chromaffin cells.

OBJECTIVE: Human pheochromocytoma tumor cells express glucagon receptors, and bolus i.v. glucagon injection rapidly increases plasma epinephrine levels, suggesting that glucagon can directly stimulate adrenomedullary secretion. In this study, we tested whether the catecholamine secretory response to glucagon was present in bovine chromaffin cells or exclusive to the tumor cells. DESIGN AND METHODS: Adrenomedullary cells were cultured in 24-well plates (10(6) cells per well). After 48-72 hours, wells were incubated for 1-20 minutes with (1) incubation medium (control), (2) catecholamine secretagogues (nicotine or potassium ion), or (3) glucagon (10(-8) to 10(-5) M). After incubation, catecholamine contents in medium and cells were assayed by high-pressure liquid chromatography with electrochemical detection. Fractional release rates of epinephrine, norepinephrine, and dopamine were calculated and compared to controls. Reverse-transcriptase PCR was performed to compare expression of mRNA of the glucagon receptor in chromaffin cells and pheochromocytoma cells. RESULTS: Nicotine and potassium evoked time-dependent release of epinephrine, norepinephrine, and dopamine. Glucagon did not affect catecholamine secretion at any concentration. Reverse-transcriptase PCR failed to detect mRNA for glucagon receptor in bovine adrenomedullary cells, but did detect it in human pheochromocytoma cells. CONCLUSIONS: In contrast to pheochromocytoma tumor cells, bovine adrenomedullary chromaffin cells do not express the glucagon receptor, and therefore do not secrete catecholamines in response to glucagon.

TNFalpha stimulated ATP-sensitive potassium channels and attenuated deoxyglucose and Ca uptake of H9c2 cardiomyocytes.

Tumor necrosis factor (TNFalpha) is an inflammatory cytokine that induces programmed cell death in a variety of tissue types, including the heart. Recent experimental data suggest that the TNF expressed within the myocardium in response to environmental injury plays an important role in initiating homeostatic response. The effect of TNFalpha (10-50 ng/mL) was studied on (86)Rb efflux, (3)H-deoxyglucose uptake, or (45)Ca uptake in H9c2 cardiomyocytes. TNFalpha stimulated (86)Rb efflux from cultures, while 2 micro M glibenclamide blocker of ATP-sensitive potassium channels or 20 micro M zvad-fmk caspase inhibitor attenuated this effect. TNFalpha also depressed the stimulatory effect of 80 mM KCl on (45)Ca uptake in the cardiomyocytes. TNFalpha inhibited the stimulatory effect of 100 nM insulin on (3)H-deoxyglucose uptake. Our findings further suggest that TNFalpha mediated adaptive and protective effects in the heart during a brief environmental injury.

Treatment with atorvastatin improves small artery compliance in patients with severe hypercholesterolemia.

BACKGROUND: We studied the effect of atorvastatin on arterial compliance in patients with severe hypercholesterolemia. METHODS: Seventeen patients with low-density lipoprotein cholesterol levels above 170 mg/dL, were included in the study, none of whomever received hypolipidemic medication or had other risk factors. Patients were followed for five visits, every 4 weeks. RESULTS: After 20 weeks of treatment, lipid profile improved significantly. Large artery elasticity index did not change significantly, but small artery elasticity index increased by 21% (4.6+/-0.5 to 5.6+/-0.9, P < .01). Although none of our patients suffered from hypertension, both systolic and diastolic blood pressure (BP) decreased significantly (6 mm Hg and 3 mm Hg, respectively). CONCLUSIONS: We conclude that atorvastatin improves the elasticity of small arteries and reduces systolic and diastolic BP in patients with severe hypercholesterolemia.

Randomized, placebo-controlled trial of the anti-tumor necrosis factor antibody fragment afelimomab in hyperinflammatory response during severe sepsis: The RAMSES Study.

OBJECTIVE: This study investigated whether treatment with the anti-tumor necrosis factor-alpha monoclonal antibody afelimomab would improve survival in septic patients with serum interleukin (IL)-6 concentrations of >1000 pg/mL. DESIGN: Multicenter, double-blind, randomized, placebo-controlled study. SETTING: Eighty-four intensive care units in academic medical centers in Europe and Israel. PATIENTS: A total of 944 septic patients were screened and stratified by the results of a rapid qualitative immunostrip test for serum IL-6 concentrations. Patients with a positive test kit result indicating IL-6 concentrations of >1000 pg/mL were randomized to receive either afelimomab (n = 224) or placebo (n = 222). Patients with a negative IL-6 test (n = 498) were not randomized and were followed up for 28 days. INTERVENTIONS: Treatment consisted of 15-min infusions of 1 mg/kg afelimomab or matching placebo every 8 hrs for 3 days. Standard surgical and intensive care therapy was otherwise delivered. MEASUREMENTS AND MAIN RESULTS: The study was terminated prematurely after an interim analysis estimated that the primary efficacy end points would not be met. The 28-day mortality rate in the nonrandomized patients (39.6%, 197 of 498) was significantly lower (p <.001) than that found in the randomized patients (55.8%, 249 of 446). The mortality rates in the IL-6 test kit positive patients randomized to afelimomab and placebo were similar, 54.0% (121 of 224) vs. 57.7% (128 of 222), respectively. Treatment with afelimomab was not associated with any particular adverse events. CONCLUSIONS: The IL-6 immunostrip test identified two distinct sepsis populations with significantly different mortality rates. A small (3.7%) absolute reduction in mortality rate was found in the afelimomab-treated patients. The treatment difference did not reach statistical significance.

Breathing-control lowers blood pressure.

We hypothesise that routinely applied short sessions of slow and regular breathing can lower blood pressure (BP). Using a new technology BIM (Breathe with Interactive Music), hypertensive patients were guided towards slow and regular breathing. The present study evaluates the efficacy of the BIM in lowering BP. We studied 33 patients (23M/10F), aged 25-75 years, with uncontrolled BP. Patients were randomised into either active treatment with the BIM (n = 18) or a control treatment with a Walkman (n = 15). Treatment at home included either musically-guided breathing exercises with the BIM or listening to quiet music played by a Walkman for 10 min daily for 8 weeks. BP and heart rate were measured both at the clinic and at home with an Omron IC BP monitor. Clinic BP levels were measured at baseline, and after 4 and 8 weeks of treatment. Home BP measurements were taken daily, morning and evening, throughout the study. The two groups were matched by initial BP, age, gender, body mass index and medication status. The BP change at the clinic was -7.5/-4.0 mm Hg in the active treatment group, vs -2.9/-1.5 mm Hg in the control group (P = 0.001 for systolic BP). Analysis of home-measured data showed an average BP change of -5.0/-2.7 mm Hg in the active treatment group and -1.2/+0.9 mm Hg in the control group. Ten out of 18 (56%) were defined as responders in the active treatment group but only two out of 14 (14%) in the control group (P = 0.02). Thus, breathing exercise guided by the BIM device for 10 min daily is an effective non-pharmacological modality to reduce BP.

Renoprotective effect of angiotensin II receptor antagonists in experimental chronic renal failure.

We compared the antihypertensive and renoprotective effects of the angiotensin II receptor antagonist losartan and the calcium channel blocker verapamil in the rat with chronic renal failure. One month after five-sixths nephrectomy, male WKY rats were treated for 2 months with either losartan or verapamil. Both resulted in a similar reduction in blood pressure: from 147.1 to 112 mm Hg in losartan-treated and from 155 to 118 mm Hg (p = NS) in verapamil-treated rats. Losartan improved the creatinine clearance (difference + 17.1% as compared with + 6.6% for verapamil, p = 0.039) and prevented the increase in proteinuria: 12.26 +/- (SE) 2.33 mg/day before and 18.48 +/- 2.19 mg/day (p = NS) after therapy in the losartan-treated and 17.27 +/- 2.73 mg/day before and 32.27 +/- 10.29 mg/day after therapy (p = 0.0484) in the verapamil-treated group. In addition, losartan resulted in minimal mesangial proliferation and significantly less glomerular sclerosis and thickening of the small arterial and arteriolar walls. The changes in interstitial fibrosis and tubular hypertrophy, however, were similar in both the verapamil- and losartan-treated groups. Treatment with losartan 1 month after five-sixths nephrectomy in male WKY rats resulted in reduced blood pressure, similar to that of the verapamil-treated group. However, despite similar antihypertensive properties, losartan improved creatinine clearance and reduced proteinuria. The losartan-treated group also had a marked reduction in mesangial proliferation and less glomerular sclerosis and less reduced vascular wall thickness in renal small arteries and arterioles. However, losartan did not totally eliminate nephrosclerosis. The tubular and interstitial changes were fewer in the losartan-treated group. Thus losartan has an additional, although only partial, renoprotective effect when compared with verapamil.

Simvastatin induces apoptosis of cultured rat cardiomyocytes.

Considering the therapeutic effect of statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) and simvastatin in patients with coronary heart disease, our first hypothesis was that simvastatin should inhibit apoptosis (programmed cell death) in angiotensin II-treated cultured myocytes. But after realizing that simvastatin stimulates apoptosis, we changed our hypothesis and began to study its apoptotic effect in primary cultured rat cardiomyocytes. We found that simvastatin induced apoptosis in a dose-dependent manner (0.1 to 3 micromol/L), as evidenced by the appearance of increased DNA fragmentation in agarose gels and characteristic apoptotic patterns in nuclei labeled with Hoechst 33342, as well as increased activity of caspase 3. FACS analysis of simvastatin-treated cardiomyocytes showing annexin V binding and propidium iodide exclusion ruled out the possibility of necrosis. Increased intracellular enzymatic activity of creatine phosphokinase, aldolase, and lactic dehydrogenase, markers for normal cell function, could reflect the hypertrophic effect of simvastatin. The results indicate that simvastatin-induced apoptosis in cultured heart cells is concentration-dependent and additive to the apoptotic effect of angiotensin II.

[The Israeli trial with cilazapril (Vasocase) for the treatment of hypertension--summary of the care of 413 patients in a community health setting].

In a multicenter study in community clinics, 413 patients with mild to moderate essential hypertension were treated with cilazapril (Vasocase), 2.5 mg daily. Patients had either been untreated or had developed side-effects from previous antihypertensive treatment. When response was inadequate the dose was either increased to 5 mg or another antihypertensive medication was added, or both. Treatment significantly reduced systolic and diastolic blood pressures. Pulse rate decreased significantly from the second month of treatment onwards. At the end of the 3rd month of treatment blood pressure was normalized or had decreased by more than 10 mmHg in 91.9% of patients. Physicians' evaluations revealed improvement in 62%; patients' self-evaluations suggested improvement in 61%. Efficacy was equal in all age groups and in both obese and nonobese patients. Antihypertensive response was superior in those with normal renal function. Side-effects were rare and similar to those reported in the literature.

[Israeli experiences of treatment of hypertension with losartan (Ocsaar)--summary of the treatment of 421 patients in community health centers].

The efficacy, safety and side-effects of treatment with losartan (Ocsaar) was studied for the first time in Israel in a large group of patients with mild to moderate hypertension in several community clinics. The 421 patients (51% men) aged 30-86 years (mean 58.6) received 50 mg of losartan daily, increased when necessary to 100 mg, and/or a second antihypertensive drug was given. After 4 weeks blood pressure was normalized in 344 and after 12 weeks in 363. Side-effects were minimal and treatment was effective in all age groups.

Uptake of glucose analogs reflects the rate of contraction of cultured myocytes.

The present study demonstrates that: a) adenosine and R-N6-(2-phenylisopropyl)-adenosine (R-PIA, A1 and A3 adenosine receptor agonist) inhibited [3H]deoxyglucose uptake or [3H]3-O-methyl-D-glucose uptake; b) sugar uptake reflects the rate of contraction in cardiac cultures; c) [3H]deoxyglucose uptake or [3H]3-O-methyl-D-glucose uptake are useful quantitative probes for beating rate evaluation. A 25-40% decrease in [3H]deoxyglucose uptake (p < 0.01) was obtained following 13-21 min treatment with 100 microM adenosine together with 1 microM dipyridamole or with 10 microM R-PIA, which inhibited spontaneous contractions. Adenosine (10 microM) attenuated spontaneous beating rate and inhibited approximately 55% of the [3H]deoxyglucose uptake following 22 h treatment (p < 0.01). 1 microM R-PIA also attenuated beating rate following either a short (1 min) or long (24 h) application and decreased [3H]deoxyglucose uptake by 20-30% (p < 0.01) during 0.5-24 h of treatment. A 157 +/- 9% and 205 +/- 11% increase (p < 0.01) in [3H]deoxyglucose uptake was obtained at 27 and 37 degrees C, respectively, compared with the uptake at 17 degrees C, which completely inhibited spontaneous contractions. Similar results [33 +/- 6% (p < 0.01) and 21 +/- 8% (p < 0.05) inhibition in [3H]deoxyglucose uptake] were obtained following 2 and 22 h of carbamylcholine treatment, respectively. This treatment also reduced spontaneous contractions. [3H] 3-O-Methyl-D-glucose uptake also decreased by 31 +/- 12% (p < 0.05) as a result of the arrest of contractions by adenosine. Elevations of 90 +/- 13% and 34 +/- 11% (p < 0.01) in [3H]deoxyglucose uptake were obtained following treatment with isoprenaline after 2 and 22 h application, respectively. It is concluded that adenosine and R-PIA inhibited [3H]deoxyglucose uptake or [3H] 3-O-methyl-D-glucose uptake in rat heart culture and that there is a linkage between the rate of cardiac contractions in culture and sugar uptake.

The effects of angiotensin II, endothelin-1, and protein kinase C inhibitor on DNA synthesis and intracellular calcium mobilization in vascular smooth muscle cells from young normotensive and spontaneously hypertensive rats.

Angiotensin II (Ang-II) and endothelin 1 (ET-1) are important peptides that induce a prolonged vasoconstriction and enhance proliferation of vascular smooth muscle cells (VSMC). These substances may have an important role in the development of hypertension and atherosclerosis. Our objectives were to determine whether there are inborn differences in the proliferation patterns of VSMC obtained from spontaneously hypertensive (SHR) and Wistar-Kyoto rats (WKY) by studying the effects of Ang-II and ET-1 on VSMC from those strains before the onset of hypertension, and to evaluate the roles of protein kinase C (PKC) and intracellular Ca2+ in the mechanism of action of ET-1 and Ang-II. VSMC from aortas of young (1- to 2-week-old) SHR and WKY rats were grown as primary cultures in plates for 48 h. The cells were incubated with Ang-II (0.1 to 1000 nmol/L) or ET-1 (0.1 to 100 nmol/L). VSMC were also incubated in the presence of various concentrations of a PKC inhibitor, chelerythrine (0.1-10 nmol/L). Thymidine incorporation into DNA was measured as an indicator of DNA synthesis. Intracellular free Ca2+ was determined by using FURA-2AM. ET-1 and Ang-II caused a marked dose-dependent enhancement of thymidine incorporation into DNA. The responses of VSMC from WKY and SHR to Ang-II and ET-1 were similar. In both strains, chelerythrine caused a dose-dependent suppression in the activity of ET-1 and Ang-II. However, VSMC from SHR incubated in the presence of ET-1 were more susceptible to the inhibitory effect of chelerythrine. Both Ang-II and ET-1 induced an increase of intracellular free Ca2+. ET-1 induced a larger increase than Ang-II (190% and 100% greater than baseline free Ca2+ levels, respectively), in spite of a lower concentration of ET-1 (ET-1 = 30 nmol/L; Ang-II = 100 nmol/L). Ang-II and ET-1 exerted a similar mitogenic effect on primary cultures of VSMC obtained from young SHR before the development of hypertension, compared with WKY. The mitogenic activity of Ang-II and ET-1 was accompanied by an increase of intracellular free Ca2+. The effect of ET-1 upon intracellular Ca2+ was stronger than that of Ang-II. VSMC cultures of SHR stimulated with ET-1 were more susceptible to PKC inhibition than those of WKY. The similarity of the effects of Ang- II and ET-1 on SHR and WKY does not exclude their role in the pathogenesis of hypertension and atherosclerosis, and further studies should be carried out to determine their role.

Glucagon-like peptide-1 structure, function and potential use for NIDDM.

Basic research on the cellular mechanisms that control the expression of the gene encoding glucagon has led to the discovery of proglucagon. This precursor is processed by tissue-specific proteolysis to produce glucagon in pancreatic alpha-cells and a glucagon-like peptide-1 (GLP-1) in the intestine. GLP-1 is a hormone that is released by intestinal cells into the circulation in response to food intake. GLP-1 and gastric inhibitory peptide (GIP) which has also been termed glucose-dependent insulinotropic peptide appear to account for most of the incretin effect in the augmentation of glucose-stimulated insulin secretion. These two hormones have specific beta-cell receptors that are coupled to GTP binding proteins to induce production of cyclic AMP and activation of cyclic AMP-dependent protein kinase. It is proposed that at least one factor contributing to the pathogenesis of non-insulin-dependent diabetes mellitus (NIDDM) is desensitization of the GLP-1 receptor on beta-cells. At pharmacological doses, infusion of GLP-1, but not of GLP, can improve and enhance postprandial insulin response in NIDDM patients. Agonists of GLP-1 receptor have been proposed as new potential therapeutic agents in NIDDM patients. The observations that GLP-1 induces both secretion and production of insulin, and that its activities are mainly glucose-dependent, led to the suggestion that GLP-1 may present a unique advantage over sulfonylurea drugs in the treatment of NIDDM.