A Technology-Assisted Web Application for Consumer Access to a Nonprescription Statin Medication

BACKGROUND

Although statins reduce adverse cardiovascular outcomes, less than one-half of eligible patients receive treatment. A nonprescription statin has the potential to improve access to statins.

OBJECTIVES

This study sought to assess concordance between clinician and consumer assessment of eligibility for nonprescription statin treatment using a technology assisted self-selection Web application (Web App) and evaluate effect on low-density lipoprotein cholesterol (LDL-C) levels.

METHODS

This study was a prospective actual use 6-month study to evaluate use of a Web App to qualify participants without a medical background for a moderate-intensity statin based on current guidelines. Participants entered demographic information, cholesterol values, blood pressure, and concomitant medications into the Web App, resulting in 3 possible outcomes: "do not use," "ask a doctor," and "OK to use."

RESULTS

The study included 1,196 participants, with a median age of 63 years (Q1-Q3: 57-68 years); 39.6% were women, 79.3% were White, 11.7% were Black, and 4.1% had limited literacy. Mean LDL-C was 139.6 ± 28.3 mg/dL and the median calculated 10-year risk of atherosclerotic cardiovascular disease was 10.1% (Q1-Q3: 7.3%-14.0%). Initial Web App self-selection resulted in an outcome concordant with clinician assessment in 90.7% (95% CI: 88.9%-92.3%) of participants, and 98.1% (95% CI: 97.1%-98.8%) had a concordant final use outcome during treatment. Mean percent change in LDL-C was -35.5% (95% CI: -36.6% to -34.3%). Serious adverse events occurred in 27 (2.3%) participants, none related to the study drug.

CONCLUSIONS

In this actual use study, a technology-assisted Web App allowed >90% of consumers to correctly self-select for statin use and achieve clinically important LDL-C reductions. (Technology-Assisted Cholesterol Trial in Consumers [TACTiC]; NCT04964544).

Comparative Effects of Low-Dose Rosuvastatin, Placebo, and Dietary Supplements on Lipids and Inflammatory Biomarkers

BACKGROUND

Supplements are commonly used by individuals with indications for lipid-lowering therapy, but evidence of their effectiveness to lower low-density lipoprotein cholesterol (LDL-C) is lacking, particularly when compared with statins.

OBJECTIVES

The trial objective was to compare the efficacy of a low-dose statin with placebo and 6 common supplements in impacting lipid and inflammatory biomarkers.

METHODS

This was a single-center, prospective, randomized, single-blind clinical trial among adults with no history of atherosclerotic cardiovascular disease (ASCVD), an LDL-C of 70 to 189 mg/dL, and an increased 10-year risk of ASCVD. Participants were randomized to rosuvastatin 5 mg daily, placebo, fish oil, cinnamon, garlic, turmeric, plant sterols, or red yeast rice. The primary endpoint was the percent change in LDL-C from baseline for rosuvastatin 5 mg daily compared with placebo and each supplement after 28 days. The primary endpoint was evaluated in a hierarchical fashion with rosuvastatin first compared with placebo, then each supplement in a prespecified order using analysis of covariance.

RESULTS

A total of 190 participants completed the study. The percent LDL-C reduction with rosuvastatin was greater than all supplements and placebo (P < 0.001). The difference in LDL-C reduction with rosuvastatin compared with placebo was -35.2% (95% CI: -41.3% to -29.1%; P < 0.001). None of the dietary supplements demonstrated a significant decrease in LDL-C compared with placebo. Adverse event rates were similar across study groups.

CONCLUSIONS

Among individuals with increased 10-year risk for ASCVD, rosuvastatin 5 mg daily lowered LDL-C significantly more than placebo, fish oil, cinnamon, garlic, turmeric, plant sterols, and red yeast rice. (Supplements, Placebo, or Rosuvastatin Study [SPORT]; NCT04846231).

Technology-Assisted Self-Selection of Candidates for Nonprescription Statin Therapy

BACKGROUND

Although statins reduce cardiovascular morbidity and mortality, only about one-half of eligible patients receive treatment. Safe and appropriate consumer access to statins could have a significant positive public health impact.

OBJECTIVES

This study compares the concordance between a participant and clinician assessment of eligibility for statin therapy using a technology-assisted approach.

METHODS

A total of 500 participants, 83 with limited literacy, completed an at-home Web-based application to assess appropriateness for treatment with rosuvastatin 5 mg. The Web application is designed to assess eligibility for a moderate-intensity statin based on current guidelines and deny access to individuals with contraindications to rosuvastatin. Subsequently, participants visited a research site where clinicians, blinded to the information the participant entered, performed an independent Web application assessment. The Web application is programmed for 1 of 3 rosuvastatin treatment outcomes: "OK to use," "not right for you," or "ask a doctor." The primary endpoint was the percent of participants whose self-selected eligibility for nonprescription rosuvastatin was concordant with clinician assessment.

RESULTS

For the primary endpoint, participant selection for statin therapy was concordant with clinician selection in 481 (96.2%) of 500 participants (95% confidence interval: 94.1%-97.7%), of whom 23 (4.6%) were deemed appropriate and 458 (91.6%) were deemed inappropriate for treatment. Discordance was due to incorrect self-selection ("OK to use") in 3 cases, incorrect rejection ("not right for you") in 14 cases and an incorrect "ask a doctor" outcome in 2 cases.

CONCLUSIONS

The use of a technology-assisted approach to consumer self-selection for statin therapy resulted in participant self-selection that showed substantial agreement with clinician selection.

Safety of rosuvastatin

The safety and tolerability of rosuvastatin were assessed (as of August 2003) using data from 12,400 patients who received 5 to 40 mg of rosuvastatin in a multinational phase II/III program, which represented 12,212 patient-years of continuous exposure to rosuvastatin. An integrated database was used to examine adverse events and laboratory data. In placebo-controlled trials, adverse events, irrespective of causality assessment, occurred in 57.4% of patients who received 5 to 40 mg of rosuvastatin (n = 744) and 56.8% of patients who received placebo (n = 382). In fixed-dose trials with comparator statins, 5 to 40 mg of rosuvastatin showed an adverse event profile similar to those for 10 to 80 mg of atorvastatin, 10 to 80 mg of simvastatin, and 10 to 40 mg of pravastatin. Clinically significant elevations in alanine aminotransferase (>3 times the upper limit of normal) and creatine kinase (>10 times the upper limit of normal) were uncommon (<or=0.2%) in the groups that received rosuvastatin and comparator statins. Myopathy (creatine kinase >10 times the upper limit of normal with muscle symptoms) that was possibly related to treatment occurred in <or=0.03% of patients who took rosuvastatin at doses <or=40 mg. A positive finding of proteinuria with dipstick testing at rosuvastatin doses <or=40 mg was comparable to that seen with other statins, and the development of proteinuria was not predictive of acute or progressive renal disease. No deaths in the program were attributed to rosuvastatin, and no rhabdomyolysis occurred in patients who received 5 to 40 mg of rosuvastatin. Rosuvastatin was well tolerated by a broad range of patients who had dyslipidemia, and its safety profile was similar to those of the comparator statins investigated in this extensive clinical program.

Rosuvastatin-induced arrest in progression of renal disease

Preclinical and limited clinical data suggest that statins decrease the progressive decline in renal function that occurs in patients with renal disease. Pooled analysis of data obtained from a population of hyperlipidemic patients enrolled in the rosuvastatin (Crestor) clinical development program permitted assessment of its effects on renal function both early and later in the course of treatment. Study participants were initially included in controlled clinical trials that evaluated the lipid-lowering efficacy and safety of rosuvastatin when compared with placebo or other lipid-lowering agents (i.e., atorvastatin, simvastatin, pravastatin, cholestyramine, fenofibrate or extended-release niacin). The median duration of treatment with the various doses of statins in these trials was approximately 8 weeks. Following completion of a controlled clinical trial, patients were permitted to enter an open-label extension trial and received rosuvastatin treatment. These data permitted assessment of renal function in a diverse group of over 10,000 patients who received rosuvastatin in its recommended dose range (5-40 mg) for up to 3.8 years. Mean serum creatinine concentrations were lower when compared with baseline both early and later in the course of rosuvastatin treatment. In contrast, no change in mean serum creatinine was observed with placebo. Mean glomerular filtration rates (GFR) predicted from the Modification of Diet in Renal Disease (MDRD) equation were higher when compared with baseline both early and later in the course of rosuvastatin treatment. No change in GFR was observed in the placebo group. Among patients who received long-term rosuvastatin treatment (> or =96 weeks), GFR was unchanged or tended to increase, rather than decrease, when compared with baseline irrespective of age, gender, hypertensive or diabetic status, level of renal function (GFR > or =60 vs. <60 ml/min/1.73 m(2)) at entry or urine dipstick protein status prior to or during the period of treatment. These findings suggest that rosuvastatin may arrest the progression of renal disease.

Beneficial effects of rosuvastatin alone and in combination with extended-release niacin in patients with a combined hyperlipidemia and low high-density lipoprotein cholesterol levels

Patients with combined hyperlipidemia and low high-density lipoprotein (HDL) cholesterol levels may benefit from combination therapy with a statin and niacin; therefore, we assessed the efficacy and safety of rosuvastatin and extended-release (ER) niacin alone and in combination in 270 patients with this atherogenic dyslipidemia. Men and women > or =18 years with fasting total cholesterol levels > or =200 mg/dl, triglycerides 200 to 800 mg/dl, apolipoprotein B > or cf=110 mg/dl, and HDL cholesterol <45 mg/dl were randomized to 1 of 4 treatments in this 24-week, open-label, multicenter trial: rosuvastatin 10 to 40 mg; ER niacin 0.5 to 2 g; rosuvastatin 40 mg/ER niacin 0.5 to 1 g; or rosuvastatin 10 mg/ER niacin 0.5 to 2 g. Percent changes from baseline in low-density lipoprotein (LDL) cholesterol, non-HDL cholesterol, and other lipid measurements at week 24 were determined by analysis of variance, with statistical testing performed separately between the rosuvastatin monotherapy group and each remaining treatment group. Daily doses of rosuvastatin 40 mg reduced LDL and non-HDL cholesterol significantly more than either ER niacin 2 g or rosuvastatin 10 mg/ER niacin 2 g (-48% vs -0.1% and -36% for LDL cholesterol and -49% vs -11% and -38% for non-HDL cholesterol, respectively; p <0.01 for all comparisons); no additional reduction in LDL or non-HDL cholesterol was observed with the combination of rosuvastatin 40 mg/ER niacin 1.0 g (-42% and -47%; p = NS). Triglyceride reductions ranged from -21% (ER niacin monotherapy) to -39% (rosuvastatin 40 mg/ER niacin 1 g), but no observed differences were statistically significant. Compared with rosuvastatin alone, rosuvastatin 10 mg/ER niacin 2 g produced significantly greater increases in HDL cholesterol (11% vs 24%, p <0.001) and apolipoprotein A-I (5% vs 11%, p <0.017). Similar increases in HDL cholesterol and apolipoprotein A-I were noted between the monotherapy groups. Over 24 weeks, rosuvastatin alone was better tolerated than either ER niacin alone or the combinations of rosuvastatin and ER niacin.

Guidelines for lowering lipids to reduce coronary artery disease risk: a comparison of rosuvastatin with atorvastatin, pravastatin, and simvastatin for achieving lipid-lowering goals

Both the National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III and the Second Joint Task Force of European Societies guidelines have established low-density lipoprotein (LDL) cholesterol goals for lipid-lowering treatment to reduce the risk of coronary artery disease. Data from 3 trials that compared rosuvastatin 10 mg (n = 389) with atorvastatin 10 mg (n = 393) and 2 trials that compared rosuvastatin 10 mg (n = 226) with pravastatin 20 mg (n = 252) and simvastatin 20 mg (n = 249) were pooled separately to compare the achievement of LDL cholesterol goals over 12 weeks of treatment in hypercholesterolemic patients. Noncomparative pooling of rosuvastatin 10 mg results from all 5 trials (n = 615) showed that 80% achieved NCEP ATP III goals and 81% achieved the European goal of <3.0 mmol/L. Compared with atorvastatin 10 mg, significantly more patients treated with rosuvastatin 10 mg achieved their ATP III (76% vs 53%) and European (82% vs 51%) goals (p <0.001). Also, in comparisons with simvastatin 20 mg and pravastatin 20 mg, 86% of patients treated with rosuvastatin 10 mg achieved ATP III goals, compared with 64% of simvastatin-treated patients and 49% of pravastatin-treated patients (p <0.001). The proportions of patients who achieved the European goal were 80%, 48%, and 16% for rosuvastatin 10 mg, simvastatin 20 mg, and pravastatin 20 mg, respectively, in this comparison (all p <0.001). A total of 71% of patients treated with rosuvastatin 10 mg who had triglyceride levels > or =200 mg/dL met both their LDL cholesterol and their non-high-density lipoprotein cholesterol goals.

Comparison of effects of nisoldipine-extended release and amlodipine in patients with systemic hypertension and chronic stable angina pectoris

The efficacy and safety of nisoldipine-extended release (ER) and amlodipine were compared in a 6-week multicenter, randomized, double-blind, double-dummy, parallel group, titration-to-effect trial in patients with stage 1 to 2 systemic hypertension (90 to 109 mm Hg diastolic blood pressure [BP]) and chronic stable angina pectoris. After a 3-week placebo run-in period, patients (n = 120) were randomly assigned to active treatment with either nisoldipine-ER (20 to 40 mg) or amlodipine (5 to 10 mg) once daily, titrated as necessary after 2 weeks to achieve diastolic BP <90 mm Hg. After 6 weeks, the mean reduction in systolic/diastolic BP from baseline was 15/13 mm Hg with nisoldipine-ER and 13/11 mm Hg with amlodipine (p = NS/p = NS). Both drugs resulted in similar BP responder rates (diastolic BP <90 mm Hg in 87% of patients who received nisoldipine-ER and 78% of patients on amlodipine, p = NS) and anti-ischemic responder rates (increasing exercise time >20% in 20% and 27%, respectively [p = NS], and increasing exercise time >60 seconds in 32% and 29% of patients, respectively [p = NS]. Also, after 6 weeks of active therapy, there was a similar mean increase in total exercise duration (23 seconds in the nisoldipine-ER group and 21 seconds in the amlodipine group, p = NS). Neither drug increased heart rate and both decreased frequency of anginal episodes. Adverse events were infrequent, and typically were vasodilator-related effects (including headache and peripheral edema) that occurred with somewhat higher incidence in the nisoldipine-ER group. Thus, nisoldipine-ER and amlodipine provided comparable antihypertensive and anti-ischemic efficacy, and both were generally well tolerated.

Differential effects of morning and evening dosing of nisoldipine ER on circadian blood pressure and heart rate

The time of administration of once-daily antihypertensive agents may have a significant impact on blood pressure control during awake and sleep periods. Using 24-h ambulatory monitoring, we compared the effects of morning and evening dosing of the long-acting dihydropyridine calcium channel blocker, nisoldipine extended-release (ER), on circadian blood pressure (BP) and heart rate in patients with mild-to-moderate hypertension. After completing a 3-week placebo run-in period, 85 patients were randomized to morning versus evening nisoldipine ER treatment at a fixed 20-mg dose. Patients were treated for 4 weeks, followed by crossover to the alternate dosing regimen for 4 additional weeks. Twenty-four-hour ambulatory monitoring was performed at baseline and at 4 and 8 weeks after randomization. Awake and sleep times were determined by electronic activity recorders (Actigraphy). Similar least-squares (+/-SE) mean changes from baseline in 24-h BP (systolic BP/diastolic BP: -11.9/-7.4 +/- 0.6/0.5 v -11.6/-6.5 +/- 0.6/0.5 mm Hg) and heart rate (1.0/1.7 +/- 0.4/0.4 beats/min) occurred with morning and evening administration, respectively. A significantly greater effect on awake diastolic BP (systolic BP/diastolic BP: -12.6/-8.1 +/- 0.7/0.4 v -11.3/-6.4 +/- 0.7/0.4 mm Hg; P = .16/.01) was observed with morning dosing compared with evening dosing. In addition, small increases in sleep and early morning heart rate were seen with evening compared with morning administration of nisoldipine (sleep, 3.1 +/- 0.4 v 0.4 +/- 0.4 beats/min; P < .001; early morning, 3.5 +/- 0.7 v 0.5 +/- 0.7 beats/min; P = .002). These differential effects on awake BP and sleep heart rate were also observed in patients who had normal (dippers) and elevated (nondippers) BP values during sleep. Appropriate evaluation of the efficacy and safety of long-acting antihypertensive agents is essential when evening administration is being considered. In the present study, the timing of nisoldipine ER administration had no effect on mean changes in BP and heart rate over a 24-h period. However, nisoldipine ER had some differential effects during sleep and awake periods with morning relative to evening dosing.

Modulation of vascular development and injury by angiotensin II

OBJECTIVE

To examine the exact profile of expression and to determine the functional significance of the angiotensin II (Ang II), type I (AT1) and type 2 (AT2) receptors during rat aortic development and following rat carotid artery balloon injury.

METHODS

AT1 and AT2 mRNA levels in rat aortae were measured using a quantitative reverse transcription polymerase chain reaction technique. Ang II receptor function was assessed by quantitating the effects of AT1 (DuP753) and AT2 (PD123319) receptor antagonists during these processes.

RESULTS

During aortic development, AT1 expression was detected on gestational day 14, increased until embryonic day 16 (E16), after which, levels were similar throughout postnatal development. Conversely, AT2 mRNA first appeared at E16, reached maximal levels between E19 and neonatal day 1, and decreased thereafter. DNA synthesis rates decreased with aortic development (high at E15, 73.8 +/- 3.1%; dropping to 37.5 +/- 2.3% by E21). Whereas AT1 receptor antagonism accelerated this developmentally regulated decrease in DNA synthesis. AT2 receptor antagonism blunted this decrease. Because activated adult medial smooth muscle cells express a neonatal phenotype after vascular injury, we assessed Ang II receptor levels and function after carotid artery balloon injury. Both receptor subtypes increased; however, AT2 receptor mRNA expression peaked earlier than AT1 (48 to 72 h after injury). As with aortic development, DNA synthesis occurring between 24 to 48 h after injury (when AT2 receptors constitute 10% of the Ang II receptor population) decreased in DuP753-treated animals and increased in PD123319-treated animals.

CONCLUSION

These results indicate that Ang II receptors play a role in vascular development by promoting opposing effects on vascular smooth muscle cell growth.

Nocturnal reduction of blood pressure and the antihypertensive response to a diuretic or angiotensin converting enzyme inhibitor in obese hypertensive patients. TROPHY Study Group

During a 12-week, multicenter study to evaluate the efficacy and safety of lisinopril and hydrochlorothiazide (HCTZ) for the treatment of obesity-related hypertension, ambulatory blood pressure (ABP) monitoring was performed both at baseline and at study completion in 124 patients. Patients were randomized to three groups: placebo, lisinopril (10, 20, or 40 mg/day), or HCTZ (12.5, 25, or 50 mg/day). All groups were matched with regard to sex, race, age, body mass index, and waist/hip ratio. The primary analysis of ABP data revealed that both lisinopril and HCTZ effectively lowered mean 24-h systolic (SBP) and diastolic (DBP) blood pressure compared with placebo, (mean change from baseline SBP/DBP: -12.0/-8.2, -10.6/-5.5, and -0.3/-0.5 mm Hg, respectively); however, lisinopril lowered DBP better than HCTZ (P < .05). Secondary analyses of groups revealed that men responded better to lisinopril than HCTZ (-11.9/-7.3 v -6.6/-3.5 mm Hg, respectively), whereas women responded well to both drugs. White patients responded better to lisinopril than HCTZ, whereas black patients showed a significant response to HCTZ only. Response to treatment was also influenced by patient classification of 24-h blood pressure profiles, ie, "dipper" or "nondipper." Overall, the majority of obese hypertensives were nondippers. Nondippers (n = 82) responded well to both drugs (-10.4/-6.9 v -12.5/-5.7 mm Hg, P < .05 v placebo), whereas dippers (n = 42) responded to lisinopril (-11.7/ -9.4 mm Hg, P < .05 v placebo and HCTZ), but not HCTZ (-5.6/-4.1 mm Hg, P = NS v placebo). Results of 24-h ABP data show that both lisinopril and HCTZ are effective therapies for obesity-related hypertension and that response to treatment is influenced by sex, race, and dipper/nondipper status.

A comparison of nisoldipine coat-core and felodipine in the treatment of mild-to-moderate hypertension

The efficacy and safety of nisoldipine CC and felodipine were compared in a multicentre, randomised, double-blind, trial in patients with mild-to-moderate hypertension (n = 229). Following a two-week placebo run-in period, patients were randomised to 16 weeks' active treatment with nisoldipine coat core (CC) 20-40 mg or felodipine 5-10 mg once daily. At week 16, a higher proportion of patients in the nisoldipine CC group were on low-dose therapy (51% vs 36%, p = 0.07). The proportion of treatment responders was 77.8% with nisoldipine CC and 66.5% with felodipine. The mean change from baseline in systolic/diastolic blood pressure was -18.8/-13.6 mmHg with nisoldipine CC and -17.4/-11.3 mmHg with felodipine. The most common adverse events included peripheral oedema and headache; neither treatment affected heart rate. Thus, nisoldipine CC and felodipine provide comparable antihypertensive efficacy. The adverse effects of both drugs are related to their vasodilator properties and are common to the class.

Lisinopril versus hydrochlorothiazide in obese hypertensive patients: a multicenter placebo-controlled trial. Treatment in Obese Patients With Hypertension (TROPHY) Study Group

Because obesity-associated hypertension has unique hemodynamic and hormonal profiles, certain classes of antihypertensive agents may be more effective than others as monotherapy. Thus, we compared the efficacy and safety of the angiotensin-converting enzyme inhibitor lisinopril and the diuretic hydrochlorothiazide in a 12-week, multicenter, double-blind trial in 232 obese patients with hypertension. Patients with an office diastolic pressure between 90 and 109 mm Hg were randomized to treatment with daily doses of lisinopril (10, 20, or 40 mg), hydrochlorothiazide (12.5, 25, or 50 mg), or placebo. Mean body mass indexes were similar for all patients. At week 12, lisinopril and hydrochlorothiazide effectively lowered office diastolic (-8.3 and -7.7 versus -3.3 mm Hg, respectively; P<.005) and systolic (-9.2 and -10.0 versus -4.6 mm Hg, respectively; P<.05) pressures compared with placebo. Ambulatory blood pressure monitoring confirmed that lisinopril and hydrochlorothiazide effectively lowered 24-hour blood pressure compared with placebo (P<.001). Significant dose-response differences were observed between treatments. Sixty percent of patients treated with lisinopril had an office diastolic pressure <90 mm Hg compared with 43% of patients treated with hydrochlorothiazide (P<.05). Responses to therapies differed with both race and age. Neither treatment significantly affected insulin or lipid profiles; however, plasma glucose increased significantly after 12 weeks of hydrochlorothiazide therapy compared with lisinopril (+0.31 versus -0.21 mmol/L; P<.001). Hydrochlorothiazide also decreased serum potassium levels by 0.4 mmol/L from baseline. In conclusion, lisinopril was as effective as hydrochlorothiazide in treating obese patients with hypertension. Treatment with angiotensin-converting enzyme inhibitors may show greater efficacy as monotherapy at lower doses compared with thiazide diuretics, may have a more rapid rate of response, and may offer advantages in patients at high risk of metabolic disorders.

Mechanisms of natriuretic-peptide-induced growth inhibition of vascular smooth muscle cells

OBJECTIVE

While natriuretic peptides can inhibit growth of vascular muscle cells (VSMC), controversy exists as to whether this effect is mediated via the guanylate cyclase-coupled receptors, NPR-A and NPR-B, or the clearance receptor, NPR-C. The original aim of this study was to examine the mechanism by which the NPR-C receptor regulates growth.

METHODS

Rat VSMC were characterized with regard to natriuretic peptide receptor expression by RT/PCR and radioligand binding studies. The effect on growth following addition of the peptides and the ligands for NPR-C was measured by [3H]thymidine incorporation. Cyclic guanosine monophosphate (cGMP) levels were determined by radioimmunoassay and mitogen activating protein kinase activity was based on the phosphorylation of myelin basic protein.

RESULTS

In rat VSMC, passages 4-12, both atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) dose-dependently inhibited serum and PDGF-induced VSMC growth. In contrast, NPR-C specific ligands alone had no effect on cell growth but enhanced growth inhibition when co-administered with ANP and CNP. ANP and CNP also decreased PDGF-BB-stimulated MAP kinase activity. Once again, NPR-C specific ligands alone had no effect but enhanced the effects of ANP. Furthermore, a cGMP specific phosphodiesterase inhibitor dose-dependently inhibited VSMC growth and markedly enhanced natriuretic-peptide-induced inhibition at low peptide concentrations. To examine a potential mechanism for the controversy concerning the NPR-C, we investigated the autocrine expression of ANP and CNP by VSMC and found that mRNA encoding both peptides could be detected by RT/PCR.

CONCLUSION

Our findings indicate that the guanyl-cyclase-linked receptors mediate the antiproliferative actions of the natriuretic peptides on vascular smooth muscle cell growth. Moreover, we hypothesize that the apparent inhibition of growth by NPR-C specific ligands reported by others may be due to stabilization of natriuretic peptides produced by the cultured VSMC and subsequent action of these peptides at guanyl-cyclase-linked receptors.

AT1 and AT2 angiotensin receptor gene expression in human heart failure

BACKGROUND

The availability of selective antagonists for angiotensin II receptors has focused interest on the gene expression of angiotensin II-receptor subtypes in the human heart.

METHODS AND RESULTS

We analyzed expression of the AT1 and AT2 subtypes of the angiotensin II receptor in ventricular myocardium taken from 9 donor hearts before implantation and from 12 patients with heart failure (6 with dilated cardiomyopathy and 6 with ischemic heart disease). Competitive reverse transcription-polymerase chain reaction with synthetic RNA internal standards was used to detect mRNA for both subtypes and to quantify relative differences in levels between failing and non-failing ventricular myocardium. AT1- and AT2-receptor mRNA could be detected in all samples. AT1-receptor gene expression was 2.5-fold greater in nonfailing hearts than in patients with failing hearts (P = .015). There was no significant difference in AT2-receptor mRNA expression in failing and nonfailing hearts.

CONCLUSIONS

The level of expression of the angiotensin AT1 receptor appears to decrease in the failing human ventricle whereas the level of AT2 expression is unaffected. These changes parallel the changes found in human ventricular myocardium at the receptor level, suggesting that the changes in receptor level may result from changes in gene expression or mRNA stability.

The angiotensin II type 2 (AT2) receptor antagonizes the growth effects of the AT1 receptor: gain-of-function study using gene transfer

The type 1 angiotensin II (AT1) receptor is well characterized but the type 2 (AT2) receptor remains an enigma. We tested the hypothesis that the AT2 receptor can modulate the growth of vascular smooth muscle cells by transfecting an AT2 receptor expression vector into the balloon-injured rat carotid artery and observed that overexpression of the AT2 receptor attenuated neointimal formation. In cultured smooth muscle cells, AT2 receptor transfection reduced proliferation and inhibited mitogen-activated protein kinase activity. Furthermore, we demonstrated that the AT2 receptor mediated the developmentally regulated decrease in aortic DNA synthesis at the latter stages of gestation. These results suggest that the AT2 receptor exerts an antiproliferative effect, counteracting the growth action of AT1 receptor.

False-positive reversible perfusion defect during dobutamine-thallium imaging in left bundle branch block

In the presence of pre-existing left bundle branch block (LBBB) exercise stress thallium scans have been associated with false-positive septal and apical perfusion abnormalities. Recent reports have documented a lower incidence of false-positive septal perfusion defects when pharmacologic agents such as dipyridamole or adenosine are utilized in patients with LBBB. Dobutamine, a synthetic catecholamine, is being used with increasing frequency in combination with perfusion agents for the diagnosis of coronary artery disease in patients unable to achieve an adequate exercise workload. Because the positive inotropic and chronotropic actions of doubtamine are similar to the physiologic effects of treadmill exercise, it is conceivable that false-positive perfusion abnormalities will be observed in patients with pre-existing LBBB undergoing dobutamine perfusion imaging. We describe a patient with underlying LBBB who underwent dobutamine thallium imaging which revealed septal and periapical defects. Subsequent coronary angiography showed these abnormalities to be false-positive. It is concluded that septal and periapical perfusion abnormalities during dobutamine thallium imaging may be false-positive and should be interpreted cautiously.

Transcatheter delivery of c-myc antisense oligomers reduces neointimal formation in a porcine model of coronary artery balloon injury

BACKGROUND

Smooth muscle cell proliferation and extracellular matrix accumulation are the principal mechanisms leading to vascular restenosis. We have previously demonstrated the growth-inhibitory effect of antisense oligomers targeting the c-myc proto-oncogene in human smooth muscle cells. The goal of this study was to investigate whether c-myc antisense oligomers reduce neointimal formation in balloon-denuded porcine coronary arteries.

METHODS AND RESULTS

First, type I collagen synthesis, which reflects synthetic function, was markedly reduced following c-myc antisense oligomers in porcine vascular smooth muscle cells independent of the growth inhibition. These effects in vitro provided the rationale for assessing c-myc antisense oligomers in the prevention of neointima in vivo. Second, the efficiency of single transcatheter delivery of oligomers into denuded porcine coronary arteries was determined. Despite rapid plasma clearance following local delivery, oligomers persisted at the site of injection for at least 3 days, exceeding by severalfold their concentration in peripheral organs. Third, morphometric analyses were carried out in balloon-denuded coronary arteries at 1 month after transcatheter c-myc antisense oligomer administration. Maximal neointimal area was reduced from 0.80 +/- 0.17 mm2 in the control group (n = 12) to 0.24 +/- 0.06 mm2 in the antisense-treated group (n = 13, P < .01). Likewise, a significant reduction in maximal neointimal thickness was observed in the antisense-treated group (P < .01). These changes in vascular remodeling following denuding injury resulted in an increase in residual lumen from 64 +/- 6% in the control group to 81 +/- 5% in the antisense-treated group (P < .05).

CONCLUSIONS

(1) Single transcatheter administration allowed for endoluminal delivery of oligomers to the site of coronary arterial injury. (2) C-myc antisense oligomers reduced the formation of neointima in denuded coronary arteries, implying a therapeutic potential of this approach for the prevention of coronary restenosis. (3) It is postulated that the c-myc proto-oncogene is involved in the process of vascular remodeling, regulating smooth muscle cell proliferation and extracellular matrix synthesis.

Downregulation of c-myc expression by antisense oligonucleotides inhibits proliferation of human smooth muscle cells

BACKGROUND

Proliferation of smooth muscle cells (SMCs) plays an important role in vascular pathobiology, being involved in the development of coronary restenosis and atherosclerosis. The activation of nuclear proto-oncogenes appears to be a final common pathway onto which various mitogenic signals coverage. Accordingly, we attempted to determine whether the activation of the c-myc nuclear proto-oncogene is essential for human SMC proliferation and explored the possibility of inhibiting their growth using antisense oligonucleotides directed against c-myc messenger RNA (mRNA).

METHODS AND RESULTS

Proliferation of human SMCs was associated with an increase in c-myc mRNA expression after growth stimulation. Using 15-mer phosphorothioate oligonucleotides (oligomers), we tested their growth-inhibitory effect in SMCs in vitro. Antisense oligomers directed against the translation initiation region of the human c-myc gene exhibited a significant antiproliferative effect, whereas sense and mismatched oligomers did not inhibit the growth. The growth-inhibitory effect of c-myc antisense oligomers was dose dependent and preventable by an excess of sense oligomers. Furthermore, growth inhibition of SMCs treated with c-myc antisense oligomers was associated with a marked decrease in the c-myc mRNA level. Phosphorothioate oligomers remained stable in medium containing 20% serum and were detectable in SMCs as early as 1 hour after cell exposure. Intact oligomers rapidly accumulated intracellularly and persisted within human SMCs for at least 16 hours.

CONCLUSIONS

c-myc antisense oligomers reduced c-myc expression and produced a significant growth inhibition of human SMCs, indicating an important role of c-myc gene activation in the process of SMC proliferation. Furthermore, extracellular stability and rapid cellular uptake provide the basis for future studies assessing the therapeutic role of the c-myc antisense approach in reducing SMC proliferation in the process of vascular restenosis.