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.

TNFα 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.

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.

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.

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.

[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.

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.

[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.

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.

Deletion of the long arm of chromosome 7 in myelomonocytic leukemia with bone marrow eosinophilia

We report a 62-year-old man with acute myelomonocytic leukemia with bone marrow eosinophilia (M4Eo), and a deletion of the long arm of chromosome 7. The patient presented with pancytopenia, which shortly after evolved to overt leukemia. There was no response to the daunorubicin-cytosine arabinoside (Ara-C) regimen, and a remission achieved with amsacrine (AMSA)-Ara-C lasted only for a short time. On relapse, a peculiar skin rash accompanied the hematologic picture. While ANLL with chromosome 7 abnormalities usually carries adverse prognosis, patients with M4Eo (which is usually associated with chromosome 16 abnormalities) do better. The patient described here examplifies that M4Eo may be associated with del(7)(q22), and that it is the chromosomal abnormality rather than the type of leukemia that might determine the clinical outcome.

Rest and effort hemodynamic responses during prolonged treatment with felodipine, 24-h blood pressure monitoring, and echocardiographic changes

In an open study, 16 patients with moderate essential hypertension were treated with 5 or 10 mg felodipine daily for 3 months. Hemodynamic (HD) indices were assessed at rest and during isometric effort (IE) at days 0, 3 to 7, 30, 60, and 90. Treatment efficacy was evaluated by ambulatory blood pressure monitoring for (ABPM) 24 h and divided between awake and sleep periods. Left ventricular mass (LVM) was determined before and at the end of treatment. Treatment normalized blood pressure (BP) in all patients (5 mg in 7 and 10 mg in 9). Systolic diastolic and mean arterial pressure (MAP) decreased significantly during the study (P < .01). The decrease in BP was significant on day 3 to 7 (P < .01) and tended to decrease further with treatment. Resting heart rate (HR) did not change. After 3 months systolic and diastolic pressure and MAP decreased significantly. Mean HR during ABPM differed between awake and sleep hours but did not change with treatment. When ABPM was divided into daytime and nighttime the awake BP decreased after 3 months (P < .01), but sleep measurements showed only a borderline decrease (P = .05). MAP after 3 months decreased in both awake and sleep periods. LV maximal and minimal dimensions did not change during treatment. Interventricular septum, posterior wall thickness, LVM, LVM/body surface area, and LVM/height tended to decrease, however this change was not significant. Hemodynamic measurements were measured at rest, at peak IE and posteffort. During treatment rest systemic vascular resistance (SVR) and MAP decreased, and there was no difference in ventricular ejection time, HR, and cardiac index. The increase in BP at IE was not prevented by treatment. After effort MAP decreased significantly and SVR tended to decrease in treated patients. Felodipine normalized resting BP in all patients. The main antihypertensive effect came at daytime and was less during sleep. No reflex tachycardia was seen during treatment. Echocardiographic measurements showed preservation of systolic and diastolic function and a tendency of decrease in LVM. Probably longer period of treatment is needed for clear-cut regression of LVM. Felodipine did not prevent the increase in BP and SVR during isometric effort, implying that normal cardiovascular reflexes are preserved during treatment.

The addition of mibefradil to chronic hydrochlorothiazide therapy in hypertensive patients is associated with a significant antihypertensive effect

OBJECTIVE

To evaluate the antihypertensive efficacy, tolerability, safety, and dose-response characteristics of the novel calcium antagonist, mibefradil, in combination with a diuretic regimen.

DESIGN

A multinational, double-blind, randomised, placebo-controlled, parallel-design trial.

METHODS

Three hundred and seven patients whose mild-to-moderate essential hypertension remained uncontrolled after 4 weeks of treatment with hydrochlorothiazide (HCTZ) 25 mg/day and placebo were randomised to receive combined treatment with HCTZ and once-daily doses of 12.5, 25, 50, or 100 mg of mibefradil or placebo. After 8 weeks of combined treatment, HCTZ was withdrawn and the mibefradil groups continued on their respective doses for an additional 6 weeks.

RESULTS

After 8 weeks, the addition of once-daily doses of mibefradil to the initial HCTZ regimen resulted in clinically relevant, dose-related reductions in sitting diastolic blood pressure (SDBP) and sitting systolic blood pressure (SSBP) at trough, which were significantly greater in the 50 and 100 mg dose groups compared to the placebo group (P < or = 0.003). Placebo-corrected treatment effects on SDBP and SSBP at the end of the combined treatment period relative to baseline were, respectively, -4.1 and -8.0 mm Hg in the 50 mg mibefradil group and -9.5 and -8.0 mm Hg in the 100 mg mibefradil group. Therapeutic response rates to combination mibefradil and HCTZ therapy were high and dose related, reaching 82% for SDBP in the 100 mg group.

CONCLUSIONS

The addition of once-daily doses of 50 or 100 mg of mibefradil to patients whose hypertension is not controlled by HCTZ alone is well tolerated and effective in improving BP control.

Hyperinsulinemia induces myocardial infarctions and arteriolar medial hypertrophy in spontaneously hypertensive rats

To investigate the effects of hyperinsulinemia on the myocardial vessels, long acting insulin (mixtard, a combination of 30% regular human insulin and 70% NPH human insulin) was injected daily for 8 weeks, intraperitoneally, in two strains of rats, normotensive WKY and hypertensive SHR. There were four groups in all, a control group, and an insulin-injected group in each strain. The drinking water contained 10% glucose to prevent hypoglycemia in the insulin-injected rats. At the end of the 8 weeks experimental period, after measuring blood pressure and taking blood for the determination of glucose, urea, creatinine, and insulin, the rats were killed. The organs were fixed in formaldehyde. The blood glucose levels were higher at the end of the experiment, in both the placebo- (saline)-injected and the insulin-injected rats. Blood pressure rose significantly only in the insulin-injected SHR. The intramyocardial arterioles in the insulin-injected SHR had a significantly thicker vascular wall than the placebo-injected SHR, as represented by the vessel wall to lumen ratio, because of hypertrophy of the media. When compared with the placebo injected WKY rats, there was a higher wall/lumen ratio of the intramyocardial arterioles in the insulin-injected WKY, but the difference did not reach significance. Heart weights factored by body weights was significantly higher in insulin-injected as compared with placebo-injected SHR. Myocardial infarctions were observed in four of eight rats in the insulin-injected SHR group despite the fact that there were no signs of atherosclerosis or intimal thickening. It is possible that the increase in heart weight and the probable increase in metabolic activity resulting from hyperinsulinemia, together with the increased oxygen demand of the myocardium and the arteriolar narrowing, may have contributed to the occurence of myocardial infarctions in the absence of atherosclerotic coronary occlusion.

Acarbose reduces blood pressure in sucrose-induced hypertension in rats

Hypertension is often associated with impaired glucose tolerance and high insulin levels, factors that contribute to insulin resistance. The present study evaluates the effect of acarbose, a hypoglycemic drug that inhibits carbohydrate digestion in sucrose-induced hypertension in rats. The effects of diets fed to 3 groups of rats for a 16-week period were studied: sucrose + NaCl (1% wet volume [w/v]) with acarbose (0.04% wet weight [w/w]), sucrose + NaCl (1% w/v) without acarbose, and a third diet of complex carbohydrates. There was no statistical difference in the body weight between rats fed with or without acarbose. Fasting glucose levels were significantly lowered when treated with acarbose. Postprandial blood glucose and insulin levels were attenuated in rats fed sucrose + acarbose. Systolic blood pressure increased significantly (p < 0.001) in rats fed sucrose + NaCl for 3 months, whereas systolic blood pressure of acarbose-fed rats remained at the initial level. Blood pressure changes in the complex carbohydrate-fed group were lower than in rats fed sucrose. The urinary volume, Na+, and K+ of rats fed acarbose tended to increase compared to the acarbose-free diet (p < 0.05). We conclude that high insulin levels, impaired glucose tolerance and Na+ retention may contribute to the development of sucrose-induced hypertension. Acarbose prevents sucrose-induced increases in plasma glucose and insulin levels. Increases in urinary Na + may contribute indirectly to this effect with resultant normal systolic blood pressures.

Expression of opioid receptors during heart ontogeny in normotensive and hypertensive rats

BACKGROUND

The opioidergic systems are involved in modulating nociceptive stimuli. In addition, the recent results suggest that endogenous and exogenous opioids could play a role in the modulation of blood pressure and cardiac functions. However, little is known regarding the expression and role of opioid-binding sites in the heart. The decreased sensitivity to noxious stimuli in hypertensive rats raises the possibility of different developmental pattern expression of opioid-binding sites in normotensive versus hypertensive rats.

METHODS AND RESULTS

Opioid receptor expression in hearts from hypertensive and normotensive rats was studied during heart development by binding assays. From P1 until P90, the development of the heart in the two rat strains was accompanied by a gradual increase in the density of kappa-opioid receptors. Hearts from hypertensive rats expressed significantly higher levels of kappa receptors compared with those of normotensive rats. At ages older than P7, mu-opioid receptors could not be detected in hearts of both strains, whereas delta-opioid-binding sites gradually increased until reaching adult levels. Seven-day-old cardiomyocyte cultures of both rat strains expressed similar densities of delta or kappa receptors to those observed in hearts from 7-day-old neonates. The mu-binding sites were not detected in cardiomyocytes cultures. Similar to the in vivo state, cultured myocytes from hypertensive rats had significantly higher levels of kappa-binding sites (1.5 fold) compared with those of normotensive rats. The kappa sites are pertussis toxin sensitive, and the state of coupling of the receptor to G protein is similar for the two rat strains.

CONCLUSION

The role of opioid-binding sites in the heart is not completely clear. Hypertensive rats are known to be less sensitive to noxious stimuli compared with normotensive rats. It is controversial whether the site if application of noxious stimuli plays an important role in the sensitivity to pain in hypertensive rats. We suggest that the opioidergic system could play a role in the modulation of blood pressure in addition to its known effect on nociception.

Correlation between secretagogue-induced Ca2+ influx, intracellular Ca2+ levels and secretion of catecholamines in cultured adrenal chromaffin cells

Catecholamine secretion induced by various secretagogues in cultured bovine chromaffin cells has been correlated with Ca2+ influx and intracellular Ca2+ concentrations. Nicotine and high K+ caused prompt secretion of catecholamines from cells. Coincidently, both secretagogues evoked 45[Ca2+] influx with a parallel increase in free intracellular Ca2+ concentration, as determined by Quin 2 fluorescence. However, the rate of return of Ca2+ level to baseline after nicotine stimulation was more rapid than after K+ stimulation. In comparison, stimulation with veratridine produced a slow and prolonged Ca2+ influx accompanied by lower levels of intracellular Ca2+ than those observed after nicotine or K+ stimulation. Yet, during 15 min of stimulation, veratridine induced a substantial catecholamine release, which was larger than that obtained after nicotine or K+ stimulations. The Ca2+ ionophore A23187 (1 microM) induced a pronounced increase in intracellular Ca2+ levels, but did not evoke any significant catecholamine release. Finally, addition of the Ca2+ channel blocker verapamil following stimulation, at a time when intracellular Ca2+ concentration was at its peak level, did not affect the rate of decline in intracellular free Ca2+ concentration but promptly blocked Ca2+ uptake and catecholamine secretion. These findings suggest that the rate of Ca2+ influx, rather than the absolute level of intracellular Ca2+ concentration, determines the rate and extent of catecholamine release.

Pharmacological basis for functional selectivity of partial muscarinic receptor agonists

Muscarinic receptor agonists activate phosphoinositide hydrolysis and adenylate cyclase in Chinese hamster ovary cells transfected with cDNAs encoding the human muscarinic ml and m3 receptors. Whereas carbachol activates similarly both receptor subtypes, 4-[3-chlorophenyl-carbamoyloxy]-2-butynyltrimethyl ammonium chloride (McN-A-343) preferentially activates the m1 subtype over m3, in regard to both phosphoinositide hydrolysis and adenylate cyclase activity. On the other hand, oxotremorine activates phosphoinositide hydrolysis to a similar extent in both cell lines, but it activates preferentially adenylate cyclase in m1 versus m3 receptor expressing cells. Relative to carbachol, both McN-A-343 and oxotremorine activate preferentially phosphoinositide hydrolysis over adenylate cyclase in both cell lines. Prolonged incubation of cells with either carbachol, McN-A-343, or oxotremorine down-regulated the m1 receptors. This was accompanied by a parallel decrease in adenylate cyclase activity, whereas phosphoinositide hydrolysis remained relatively high. Inactivation of the receptors by alkylation with acetylethylcholine mustard, or by blocking with atropine, reduced carbachol-stimulated adenylate cyclase activity more effectively than carbachol-induced phosphoinositide hydrolysis in both m1 and m3 receptor expressing cells. These findings imply that the receptor reserve in these cell lines is greater for phosphoinositide hydrolysis response than for adenylate cyclase response. Yet, the receptor reserve for each of these responses is similar in both m1 and m3 receptor expressing cells. Since the binding affinities of McN-A-343 and of oxotremorine to m1 and m3 receptors are very similar, and since both cell lines contain similar amounts of spare receptors, we propose that the preferential activation of muscarinic m1 over m3 receptor by partial agonists is related to differences in the abilities of the two receptor subtypes to undergo conformational changes following agonist binding. This hypothesis is supported by results showing that the muscarinic m1 but not m3 receptor exhibits two affinity states in a competition binding assay.

Insulin induces medial hypertrophy of myocardial arterioles in rats

To investigate the effect of hyperinsulinemia on arteriolar hypertrophy, myocardial hypertrophy, and blood pressure, we administered insulin intraperitoneally to SHR and WKY rats for 3 consecutive weeks. To prevent hypoglycemia, the drinking water contained 10% sugar, and to accentuate the blood pressure, their chow contained 8% table salt. Blood pressure was measured by the tail-cuff method. Heart weights were factored with body weights. Arterioles of approximately 100 microns in diameter were examined at the end of the experiment and the vascular wall thickness was factored with the lumen diameter. At the end of 3 weeks, blood pressure rose in the SHR but not in the WKY rats. The heart weights in the WKY normotensive rats did not increase, whereas in the SHR they did. Furthermore, there was a significant rise in vessel wall thickness in the rats that received insulin, whether there was a rise in blood pressure or not and whether they had an increase in heart weight or not. There was a similar rise in blood glucose in all the groups, with slightly more accentuated rise in the SHR that received insulin. Nevertheless the increase in vascular wall thickness occurred only in the groups which received insulin. This seems to preclude the importance of hyperglycemia per se as the causative agent for the increase in vascular wall thickness in this study. The increase was in the form of medial hypertrophy without any sign of atherosclerosis. It seems, therefore, that hyperinsulinemia is associated with hypertrophy of the media of arterioles regardless of the increase in heart weight or the rise in blood pressure.

Hyperinsulinaemia increases blood pressure in genetically predisposed spontaneously hypertensive rats but not in normotensive Wistar-Kyoto rats

BACKGROUND

There is controversy in the literature concerning the effect of short-term insulin administration on blood pressure in different experimental situations, because in some experiments this association is clear, whereas in others it is nonexistent.

OBJECTIVE

To investigate whether there is a difference in the effect of exogenous insulin administration on the blood pressure of normotensive Wistar-Kyoto (WKY) rats and hypertensive spontaneously hypertensive rats (SHR).

METHODS

Hyperinsulinaemia was induced in normotensive WKY rats and in hypertensive SHR by the administration of long-acting insulin (insulin retard 0.4 U/kg body weight per day in one group and 0.8 U/kg body weight per day in another group) once a day, intraperitoneally, for 3 weeks. All of the rats drank a 10% sucrose solution, to prevent hypoglycaemia in those receiving insulin. RESULTS. Baseline serum levels were significantly higher in the SHR groups than in the WKY rat groups. At the end of the experiment, after 3 weeks' insulin therapy, systolic blood pressure measured by the tail-cuff method showed a significant increase in the SHR, but not in the WKY rats, possibly because of the genetic predisposition of the SHR to increase their blood pressure. The increase was similar in the SHR given 0.4 U/kg body weight per day insulin retard to that in those given 0.8 U/kg per day.

CONCLUSIONS

Exogenous insulin increased systolic blood pressure in the SHR but not in the WKY rats. The rise was similar in rats receiving either 0.4 or 0.8 U/kg body weight per day insulin retard.

Acute hemodynamic effects of nisoldipine in young hypertensive patients

The hemodynamic effects of oral nisoldiopine in 12 hypertensive patients aged 35-55 years were determined using the impedance cardiography method. Hemodynamic measurements were performed at hourly intervals before and following ingestion of the medication. Nisoldipine significantly decreased systolic and diastolic blood pressure, with a slight increase in heart rate. Stroke volume did not change significantly following the medication. Total peripheral resistance decreased gradually reaching its lowest values 2 h after ingestion of nisoldipine. We conclude that nisoldipine is a potent oral antihypertensive agent that induces peripheral vasodilatation without decrease in cardiac output.

[Psoas abscess mimicking septic arthritis of the hip]

Primary psoas abscess is a relatively rare and imposes diagnostic and therapeutic challenges. We describe a 16-year-old boy who presented with fever, limp and the clinical picture of septic arthritis of the hip joint. He did not respond to conventional medical treatment. When the diagnosis of psoas abscess was made and the abscess was drained, he gradually recovered. The diagnosis of psoas abscess is frequently missed. Correct diagnosis is very important because usually, cure only follows surgical drainage.

Opioids inhibit endothelin-mediated DNA synthesis, phosphoinositide turnover, and Ca2+ mobilization in rat C6 glioma cells

Opioid agonists inhibit DNA synthesis in C6 rat glioma cells that express opioid receptors, induced by desipramine (DMI). This inhibition was not observed in cells that were not treated with DMI, and thus did not express opioid-binding sites. Endothelin, a known mitogen, increased thymidine incorporation dose dependently (up to 1.7-fold) in DMI-treated C6 cells. This increase was reversed by an anti-idiotypic antibody to opioid receptors, Ab2AOR, which has opioid agonist properties. The opioid antagonist naltrexone blocked the inhibition caused by Ab2AOR. Endothelin also stimulated phosphoinositide (PI) turnover and this effect was inhibited by morphine (50%) or by Ab2AOR (72%) in DMI-treated but not in DMI-untreated C6 cells. These actions of morphine and Ab2AOR were reversed by naltrexone. The inhibition of PI turnover and of thymidine incorporation by Ab2AOR or morphine was insensitive to pertussis toxin (PTX). Since PI turnover is known to induce Ca2+ mobilization, it was of interest to examine the effects of the applied opioids on intracellular Ca2+ concentrations. Endothelin increased the concentration of cytosolic free Ca2+ in the cells while Ab2AOR, morphine, and beta-endorphin reversed the endothelin-induced Ca2+ mobilization in DMI-treated but not in DMI-untreated C6 cells. The effect of these agonists was also blocked by naltrexone. The results indicate that glial cells can be a target of an opioid receptor-mediated antimitogenic action and that an abatement in PI turnover and Ca2+ mobilization may be associated with this mechanism.