Colesevelam hydrochloride: reducing atherosclerotic coronary heart disease risk factors

Colesevelam HCl is a bile acid sequestrant (BAS) which has been specifically designed with a unique structure for the purpose of improving tolerability and reducing potential drug interactions compared to older BAS, such as cholestyramine and colestipol. As a class, BAS are known to reduce cholesterol and glucose levels, and to reduce atherosclerotic coronary heart disease (CHD) risk as monotherapy, and in combination with other lipid-altering drug therapies. Colesevelam HCl has specifically been shown to reduce total and low-density lipoprotein (LDL) cholesterol levels, and has been approved as a cholesterol-lowering drug since year 2000. It has also been shown to reduce glucose levels. This discussion reviews mechanisms by which BAS lower cholesterol, and potential mechanisms by which BAS lower glucose levels in patients with type 2 diabetes mellitus. Finally this paper specifically reviews colesevelam HCl's pharmacology, lipid and glucose efficacy, safety/tolerability, and clinical use.

Comparing HMG-CoA reductase inhibitors

The statins have proved to be some of the most potent therapies for reducing elevated low-density lipoprotein (LDL) cholesterol and lessening the risk of coronary heart disease (CHD) and related events. Nonetheless, there are still questions about the clinical relevance of individual drug characteristics, such as chemical derivation, solubility properties, and metabolic route, in terms of tolerability or therapeutic benefit. At the same time, no clear explanation has emerged for the significantly steeper reductions in LDL cholesterol levels achieved with atorvastatin versus lovastatin, simvastatin, pravastatin, or fluvastatin, or, more recently, with rosuvastatin versus atorvastatin, although possible mechanisms have been suggested. More studies are needed to characterize the effects of statins on high-density lipoprotein (HDL) in different patient groups. Clearly, though, several statins have yielded significant reductions in CHD risk and have shown to be well tolerated in both primary and secondary prevention trials. The possibility that statins exert pronounced effects beyond lowering blood lipids is opening other avenues of research into the benefits of these drugs.

Comparison of the effects of high doses of rosuvastatin versus atorvastatin on the subpopulations of high-density lipoproteins

Atorvastatin and rosuvastatin are both highly effective in decreasing low-density lipoprotein cholesterol and triglyceride levels. However, rosuvastatin was shown to be more effective in increasing high-density lipoprotein (HDL) cholesterol levels. The purpose of the study is to compare the effects of daily doses of rosuvastatin 40 mg with atorvastatin 80 mg during a 6-week period on HDL subpopulations in 306 hyperlipidemic men and women. We previously showed that increased levels of large alpha-1 and alpha-2 HDLs decrease the risk of coronary heart disease and protect against progression of coronary atherosclerosis (superior to HDL cholesterol). In this study, both statins caused significant increases in large alpha-1 (p <0.001) and alpha-2 (p <0.001 for rosuvastatin, p <0.05 for atorvastatin) and significant (p <0.001) decreases in small pre-beta-1 HDL levels; however, increases in the 2 large HDL particles were significantly higher for rosuvastatin than atorvastatin (alpha-1, 24% vs 12%; alpha-2, 13% vs 4%; p <0.001). Statin-induced increases in alpha-1 and alpha-2 correlated with increases in HDL cholesterol, whereas decreases in pre-beta-1 were associated with decreases in triglycerides. In subjects with low HDL cholesterol (<40 mg/dl for men, <50 mg/dl for women, n = 99), increases in alpha-1 were 32% versus 11%, and in alpha-2, 21% versus 5% for rosuvastatin and atorvastatin, respectively. In conclusion, our data show that both statins, given at their maximal doses, favorably alter the HDL subpopulation profile, but also that rosuvastatin is significantly more effective in this regard than atorvastatin.

Clinical significance of recent lipid trials on reducing risk in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus is a significant risk factor for cardiovascular disease and is associated with significant cardiovascular morbidity and mortality. Current guidelines suggest lifestyle modification and at least a 30%-40% reduction of low-density lipoprotein (LDL) cholesterol with drug therapy, to a target level of <100 mg/dL. Additional secondary therapeutic targets include increasing high-density lipoprotein (HDL) cholesterol and lowering triglycerides. Although the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) remain first-line therapy, combination therapy with statins and fibrates or niacin is often needed to achieve target levels in patients with diabetes. Statins significantly lower LDL and decrease the relative risk for nonfatal myocardial infarction (MI) or coronary artery disease death. Clinical trials have demonstrated that in high-risk patients, such as those with diabetes, monotherapy with statins reduces overall cardiovascular events by 30%-40%. Fibrates have modest effects to lower LDL, but they significantly increase HDL and reduce triglycerides, they may improve glucose tolerance, and they have been shown to reduce nonfatal MI by 25%. Although data are limited, the combination of a statin and fenofibrate significantly reduced LDL, reduced triglycerides, and increased HDL compared with a statin alone. It is hoped that ongoing trials will demonstrate the clinical outcomes benefits of combination therapy in patients with diabetes.

Directed motion for delta-kicked atoms with broken symmetries: comparison between theory and experiment

We report an experimental investigation of momentum diffusion in the delta-function kicked rotor where time symmetry is broken by a two-period kicking cycle and spatial symmetry by an alternating linear potential. We exploit this, and a technique involving a moving optical potential, to create an asymmetry in the momentum diffusion that is due to the classical chaotic diffusion. This represents a realization of a type of Hamiltonian quantum ratchet.

Dyslipidemia in Older Adults

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have been shown in many large, randomized clinical trials to be safe and highly effective for decreasing low-density lipoprotein cholesterol, thus preventing cardiovascular events and decreasing mortality in patients both with and without prior cardiovascular disease. Statins are also appropriate agents for older adults, although they remain underutilized in this population. This article uses three typical case history presentations to review the most recent clinical trial data and guidelines on statin therapy to provide practical guidance on clinical decision making for lipid-lowering therapy in the geriatric population.

Statin therapy: Is the percent reduction or the attained low-density lipoprotein cholesterol level more important?

Hyperlipidemia is a well-known risk factor for atherosclerosis. Several trials have demonstrated the importance of lowering low-density lipoprotein cholesterol (LDL-C) levels to reduce all-cause mortality, coronary ischemia, and cerebrovascular accidents. Although the optimal goal for LDL-C levels in patients with known coronary heart disease has been less than 100 mg/dL, more recent findings support achieving even lower LDL-C levels for very high-risk patients. As the target levels for LDL-C trend towards lower values, it is important to evaluate the status for optimal management with statin therapy. In this review article, we discuss the role of percent LDL-C reduction versus attained LDL-C levels as targets for statin therapy in order to maximize the preventive care provided to high-risk patients.

Optimizing Cardiovascular Outcomes in Patients with Type 2 Diabetes—Clinical Implications of the FIELD Results

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Rationale for intensive statin treatment in high-risk patients

Intensive lipid-lowering therapy with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) is now an established regimen for patients at high risk for cardiovascular events, regardless of baseline low-density lipoprotein cholesterol levels. Treatment with statins to reduce low-density lipoprotein cholesterol levels significantly below 100 mg/dL has been shown to further reduce the risk of cardiovascular morbidity and mortality in high-risk patients and has provided the necessary data for an update to the National Cholesterol Education Program's Third Adult Treatment Panel (ATP III) guidelines. Intensive statin therapy is also well tolerated, with no increased risk of noncardiovascular adverse events and a low incidence of clinically significant liver or muscle enzyme abnormalities. Results of recent clinical and surrogate end point trials confirm that intensive lowering of low-density lipoprotein cholesterol is beneficial and safe in a majority of high-risk patients.

Effectiveness and Tolerability of Adding Ezetimibe to Niacin-Based Regimens for Treatment of Primary Hyperlipidemia

OBJECTIVE

To determine the effectiveness and tolerability of adding ezetimibe, 10 mg daily, to niacin-based regimens for dyslipidemia.

METHODS

We conducted a retrospective review of medical records of 53 patients in 2 lipid clinics who received ezetimibe as add-on therapy to stable doses of niacin and other lipid medications. Mean percentage changes of lipoprotein cholesterol and triglyceride levels were determined. Safety and tolerability measures included adverse events, serum hepatic transaminases, and hemoglobin A1c (in patients with diabetes).

RESULTS

Most study subjects (81%) had established atherosclerotic disease. The niacin formulation was extended-release in 31 patients (58%), immediate-release in 17 (32%), and slow-release in 5 (9%). Most patients (75%) were also taking a statin. Add-on ezetimibe therapy yielded mean reductions of 18% for total cholesterol (P<0.001), 25% for low-density lipoprotein (LDL) cholesterol (P<0.001), and 17% for triglycerides (P<0.001). High-density lipoprotein (HDL) cholesterol did not change significantly (+2%). Only 7 patients (13%) met Adult Treatment Panel III (ATP III) LDL cholesterol goals before the addition of ezetimibe, but 24 (45%; P<0.001 compared with baseline) attained these goals after addition of ezetimibe to the therapeutic regimen. Ezetimibe effectiveness did not correlate with the baseline dose of niacin or the dose/efficacy of the statin used. The addition of ezetimibe to niacin-based therapy for dyslipidemia was well tolerated. No patient had clinically significant elevations in hepatic enzyme or hemoglobin A1c levels or discontinued the ezetimibe therapy permanently.

CONCLUSION

In our study, the addition of ezetimibe to niacin-based regimens lowered the LDL cholesterol level by 25% and did not change the level of HDL cholesterol. This combination can be useful in multidrug regimens for high-risk patients with dyslipidemia who are not achieving ATP III treatment goals.

Crohn's disease in people exposed to clinical cases of bovine paratuberculosis

Mycobacterium avium subspecies paratuberculosis (Map), the cause of ruminant paratuberculosis, has been proposed as the causative agent of Crohn's disease. The objective of this study was to determine whether exposure to clinical cases of bovine paratuberculosis was a risk factor for Crohn's disease. A questionnaire was sent to dairy farmers living on premises where the occurrence or absence of clinical cases of bovine paratuberculosis had previously been determined. The prevalence of Crohn's disease was found to be similar to that reported in other studies in the United Kingdom and showed no association with bovine paratuberculosis. There was, however, a univariate association with geographical region. Ulcerative colitis showed univariate associations with age, frequency of contact with cattle and with smoking. The results do not support the hypothesis that Map plays a causative role in the aetiology of Crohn's disease.

Eotaxin and obesity

CONTEXT

Asthma and obesity incidence is increasing worldwide, and asthma is often more severe in the obese. Eotaxin, a CC chemokine, is important in extrinsic asthma, an inflammatory disorder.

OBJECTIVE

Our objective was to examine the relation between eotaxin and obesity.

DESIGN

We conducted a comparison study of eotaxin in mice fed high-fat vs. standard chow diet for 26 wk, in obese vs. lean humans, in obese humans before and after 4-6 wk of weight loss, and in sc vs. visceral adipose tissue from patients undergoing bariatric surgery.

SETTING

Our clinical study occurred in an outpatient weight loss program.

PATIENTS

Patients were obese adults with metabolic syndrome (n = 40) and nine morbidly obese bariatric surgery patients.

INTERVENTION

Intervention was a very-low-calorie diet.

MAIN OUTCOME MEASURES

We assessed circulating eotaxin and eotaxin mRNA levels in adipose tissue.

RESULTS

Serum eotaxin levels were significantly higher in obese mice, and adipose mRNA levels correlated positively with serum eotaxin levels. Adipose tissue explants from obese mice showed increased secretion of eotaxin compared with explants from lean mice. In obese patients, plasma eotaxin levels were significantly higher than in lean controls and significantly reduced after weight loss, and eotaxin mRNA levels were 4.7-fold higher in visceral than sc adipose tissue.

CONCLUSIONS

Circulating eotaxin and eotaxin mRNA levels in visceral adipose tissue were increased in obesity in mice and humans. Adipose tissue explants secrete eotaxin, and the stromal/vascular component of adipose tissue seems to be the predominant source of eotaxin. Diet-induced weight loss in humans led to reduction in plasma eotaxin levels, demonstrating that clinical interventions that target obesity can modulate systemic eotaxin levels.

Complementary therapy to target LDL cholesterol: the role of the ezetimibe/simvastatin combination

Cardiovascular (CV) disease remains the number 1 cause of death in the USA. Nonetheless, there has been a decline in the age-adjusted death rate for coronary heart disease (CHD) which may be due to more aggressive treatment guidelines for treating CV risk factors, such as hypertension, diabetes, and dyslipidemia. The recent update to the National Cholesterol Education Program (NCEP) guidelines have recommended lower low-density lipoprotein cholesterol (LDL-C) goals in high-risk patients. Based on the new targets for LDL-C, clinicians will need more efficacious lipid-lowering therapies. One of these newer therapies is the combination of ezetimibe and simvastatin. This article reviews the implications of the updated guidelines and discusses the efficacy and safety of ezetimibe/simvastatin for lowering LDL-C.

Effective use of combination lipid therapy

Despite the benefits of statin therapy, low-density lipoprotein (LDL) cholesterol management remains suboptimal and many patients do not achieve their recommended target goals. The aim of combination lipid drug therapy in high-risk patients is to achieve LDL cholesterol and non-high-density lipoprotein (HDL) cholesterol goals with a minimum of serious adverse effects. Although statins are the drug of first choice, statin monotherapy may be limited by intolerance of dose escalation or failure to attain non-HDL cholesterol goals in those with mixed hyperlipidemia. Statins plus bile acid resins or ezetimibe can achieve greater than 50% reduction in LDL cholesterol, with little or no increase in adverse effects. Fibrates, niacin, and omega-3 fatty acids, when added to statins, can reduce triglycerides, increase HDL cholesterol, and reduce non-HDL cholesterol to a greater extent than statin monotherapy. The safety profile of combination lipid therapy is acceptable if the global coronary heart disease risk of the patient is high, thus producing a favorable risk to benefit ratio. Careful surveillance of hepatic transaminases, avoidance of gemfibrozil in statin-fibrate combinations, and awareness of statin-concomitant drug interactions is key to safe and efficacious use of combination lipid drug therapy.

Effects of insulation on the temperature within farrowing huts and the weaning weights of piglets reared on a commercial outdoor pig unit

The air temperatures inside uninsulated and insulated huts were recorded on an outdoor pig unit in the south of England between September 1997 and September 1998, and the herd's production parameters were also recorded. During the summer the temperatures inside some of the uninsulated huts exceeded 45 degrees C, but the temperatures inside the insulated huts were lower and fluctuated less. Despite the high temperatures, the weaning weight of piglets reared in the uninsulated huts were often higher than those of the piglets reared in the insulated huts, possibly as a result of the higher mortality of small piglets in the uninsulated huts, especially during the winter. The weaning weights of the piglets were higher during the summer.

Statins: the case for higher, individualized starting doses

If patients with hypercholesterolemia were started on higher doses of statins tailored to their lipid levels and risk, more of them would achieve their low-density lipoprotein cholesterol (LDL-C) goals, possibly leading to fewer cardiovascular events and deaths.

Safety of statins: effects on muscle and the liver

Although statin drugs can have adverse effects on muscles and the liver, these effects are uncommon. Caution is warranted in patients at higher risk, ie, those who are elderly, frail, or small; have multisystem disease; are receiving immunosuppressive drugs or other medications that interact with statins; or are receiving higher doses of a statin.

Effective use of combination lipid therapy

Despite the benefits of statin therapy, low-density lipoprotein cholesterol (LDL-C) management remains suboptimal and many patients do not achieve their recommended target goals. The aim of combination lipid drug therapy in high-risk patients is to achieve LDL-C and non-high-density lipoprotein cholesterol (HDL-C) goals with a minimum of serious adverse effects. Although statins are the drug of first choice, statin monotherapy may be limited by intolerance of dose escalation or failure to attain non-HDL-C goals in those with mixed hyperlipidemia. Statins plus bile acid resins or ezetimibe can achieve greater than 50% reduction in LDL-C, with little or no increase in adverse effects. Fibrates, niacin, and omega-3 fatty acids, when added to statins, can reduce triglycerides, increase HDL-C, and reduce non-HDL-C to a greater extent than statin monotherapy. The safety profile of combination lipid therapy is acceptable, if the global coronary heart disease risk of the patient is high, thus producing a favorable risk to benefit ratio. Careful surveillance of hepatic transaminases, avoidance of gemfibrozil in statin-fibrate combinations, and awareness of statin-concomitant drug interactions is key to safe and efficacious use of combination lipid drug therapy.

Comparison of the instructional efficacy of Internet-based CME with live interactive CME workshops: a randomized controlled trial

CONTEXT

Despite evidence that a variety of continuing medical education (CME) techniques can foster physician behavioral change, there have been no randomized trials comparing performance outcomes for physicians participating in Internet-based CME with physicians participating in a live CME intervention using approaches documented to be effective.

OBJECTIVE

To determine if Internet-based CME can produce changes comparable to those produced via live, small-group, interactive CME with respect to physician knowledge and behaviors that have an impact on patient care.

DESIGN, SETTING, AND PARTICIPANTS

Randomized controlled trial conducted from August 2001 to July 2002. Participants were 97 primary care physicians drawn from 21 practice sites in Houston, Tex, including 7 community health centers and 14 private group practices. A control group of 18 physicians from these same sites received no intervention.

INTERVENTIONS

Physicians were randomly assigned to an Internet-based CME intervention that could be completed in multiple sessions over 2 weeks, or to a single live, small-group, interactive CME workshop. Both incorporated similar multifaceted instructional approaches demonstrated to be effective in live settings. Content was based on the National Institutes of Health National Cholesterol Education Program--Adult Treatment Panel III guidelines.

MAIN OUTCOME MEASURES

Knowledge was assessed immediately before the intervention, immediately after the intervention, and 12 weeks later. The percentage of high-risk patients who had appropriate lipid panel screening and pharmacotherapeutic treatment according to guidelines was documented with chart audits conducted over a 5-month period before intervention and a 5-month period after intervention.

RESULTS

Both interventions produced similar and significant immediate and 12-week knowledge gains, representing large increases in percentage of items correct (pretest to posttest: 31.0% [95% confidence interval {CI}, 27.0%-35.0%]; pretest to 12 weeks: 36.4% [95% CI, 32.2%-40.6%]; P<.001 for all comparisons). Chart audits revealed high baseline screening rates in all study groups (> or =93%) with no significant postintervention change. However, the Internet-based intervention was associated with a significant increase in the percentage of high-risk patients treated with pharmacotherapeutics according to guidelines (preintervention, 85.3%; postintervention, 90.3%; P = .04).

CONCLUSIONS

Appropriately designed, evidence-based online CME can produce objectively measured changes in behavior as well as sustained gains in knowledge that are comparable or superior to those realized from effective live activities.

Multiplexed Analysis of Biomarkers Related to Obesity and the Metabolic Syndrome in Human Plasma, Using the Luminex-100 System

Background: The complex pathology of disease has sparked the development of novel protein expression profiling techniques that require validation in clinical settings. This study focuses on multiplexed analyses of adipocytokines and biomarkers linked to the metabolic syndrome, diabetes, and cardiovascular disease.

Methods: Multiplexed immunoassays using fluorescent microspheres and the Luminex-100 system were performed on plasma from 80 obese patients (40 with the metabolic syndrome) before and after 6–8 weeks of diet-induced weight loss. Leptin, insulin, C-peptide, monocyte chemoattractant protein-1 (MCP-1), eotaxin, interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and IL-6 concentrations measured with multiplex panels from 3 different manufacturers were compared with results from commercial ELISAs. Detection limits and between- and within-run imprecision were determined for each analyte. Bland–Altman analysis was used to determine agreement between multiplexed immunoassays and ELISAs.

Results: Correlation between the Luminex multiplexed assays and ELISAs was good for leptin (Linco), insulin (Linco), MCP-1 (Biosource and Upstate), and eotaxin (Biosource) with correlation coefficients of 0.711–0.895; fair for eotaxin (Upstate) and C-peptide (Linco) with correlation coefficients of 0.496–0.582; and poor for TNF-α, IL-8, and IL-6 (Linco, Biosource, Upstate, and R&D) with correlation coefficients of −0.107 to 0.318. Within- and between-run imprecision values for the multiplex method were generally &lt;15%. Relative changes in plasma leptin and insulin concentrations after diet-induced weight loss were similar whether assessed by multiplex assay or ELISA.

Conclusion: Although this technology appears useful in clinical research studies, low assay sensitivity and poor correlations with conventional ELISA methods for some analytes with very low plasma concentrations should be considered when using the Luminex platform in clinical studies.