Familial type II hyperlipoproteinemia with coronary heart disease: effect of diet-colestipol-nicotinic acid treatment

Dietary interventions (plant sterols, stanols, omega-3 fatty acids, soy protein and dietary fibers) for familial hypercholesterolaemia

BACKGROUND

A cholesterol-lowering diet and several other dietary interventions have been suggested as a management approach either independently or as an adjuvant to drug therapy in children and adults with familial hypercholesterolaemia (FH). However, a consensus has yet to be reached on the most appropriate dietary treatment. Plant sterols are commonly used in FH although patients may know them by other names like phytosterols or stanols.

OBJECTIVES

To examine whether a cholesterol-lowering diet is more effective in reducing ischaemic heart disease and lowering cholesterol than no dietary intervention in children and adults with familial hypercholesterolaemia. Further, to compare the efficacy of supplementing a cholesterol-lowering diet with either omega-3 fatty acids, soya proteins, plant sterols or plant stanols.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Inborn Errors of Metabolism Trials Register, which is compiled from electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (updated with each new issue of The Cochrane Library), quarterly searches of MEDLINE and the prospective handsearching of one journal - Journal of Inherited Metabolic Disease. Most recent search of the Group's Inborn Errors of Metabolism Trials Register: 22 August 2013. We also searched PubMed to 05 February 2012.

SELECTION CRITERIA

Randomised controlled trials, both published and unpublished, where a cholesterol-lowering diet in children and adults with familial hypercholesterolaemia has been compared to other forms of dietary treatment or to no dietary intervention were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the trial eligibility and risk of bias and one extracted the data, with independent verification of data extraction by a colleague.

MAIN RESULTS

In the 2014 update of the review, 15 trials have been included, with a total of 453 participants across seven comparison groups. The included trials had either a low or unclear risk of bias for most of the parameters used for risk assessment. Only short-term outcomes could be assessed due to the short duration of follow up in the included trials. None of the primary outcomes, (incidence of ischaemic heart disease, number of deaths and age at death) were evaluated in any of the included trials. No significant differences were noted for the majority of secondary outcomes for any of the planned comparisons. However, a significant difference was found for the following comparisons and outcomes: for the comparison between plant sterols and cholesterol-lowering diet (in favour of plant sterols), total cholesterol levels, mean difference 0.30 mmol/l (95% confidence interval 0.12 to 0.48); decreased serum LDL cholesterol, mean difference -0.60 mmol/l (95% CI -0.89 to -0.31). Fasting serum HDL cholesterol levels were elevated, mean difference -0.04 mmol/l (95% CI -0.11 to 0.03) and serum triglyceride concentration was reduced, mean difference -0.03 mmol/l (95% CI -0.15 to -0.09), although these changes were not statistically significant. Similarly, guar gum when given as an add on therapy to bezafibrate reduced total cholesterol and LDL levels as compared to bezafibrate alone.

AUTHORS' CONCLUSIONS

No conclusions can be made about the effectiveness of a cholesterol-lowering diet, or any of the other dietary interventions suggested for familial hypercholesterolaemia, for the primary outcomes: evidence and incidence of ischaemic heart disease, number of deaths and age at death,due to the lack of data on these. Large, parallel, randomised controlled trials are needed to investigate the effectiveness of a cholesterol-lowering diet and the addition of omega-3 fatty acids, plant sterols or stanols, soya protein, dietary fibers to a cholesterol-lowering diet.

Preventing Early Cardiovascular Death in Patients With Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is an autosomal dominant disorder resulting in severe elevation of total and low-density lipoprotein cholesterol levels. There are more than 600,000 individuals in the United States with FH. Individuals with FH tend to experience premature cardiovascular disease and often die from sudden cardiac death at a young age. Statins alone or in combination with other lipid-lowering medications are effective in managing FH and preventing cardiovascular events. For patients who do not respond to or are intolerant of pharmacotherapy, low-density lipoprotein apheresis is available as a nonpharmacologic treatment option. Despite the prevalence of FH, it is undiagnosed and untreated in the majority of patients. Screening, combined with appropriate drug therapy, can save lives. The authors review the screening, diagnosis, and management of FH.

Familial hypercholesterolemia: current treatment options and patient selection for low-density lipoprotein apheresis

Options for treatment of severe heterozygous and homozygous familial hypercholesterolemia prior to the statin era were limited by significant side effects and morbidity. The advent of both the statins and technology for the selective removal of LDL via apheresis have revolutionized management but challenges remain.

Dietary treatment for familial hypercholesterolaemia

BACKGROUND

A cholesterol-lowering diet and several other dietary interventions have been suggested as a management approach either independently or as an adjuvant to drug therapy in children and adults with familial hypercholesterolemia. However, a consensus has yet to be reached on the most appropriate dietary treatment.

OBJECTIVES

To examine whether a cholesterol-lowering diet is more effective in reducing ischaemic heart disease and lowering cholesterol than no dietary intervention in children and adults with familial hypercholesterolaemia. Further, to compare the efficacy of supplementing a cholesterol-lowering diet with either omega-3 fatty acids, soya proteins, plant sterols or plant stanols.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Inborn Errors of Metabolism Trials Register.Most recent search of the Group's Inborn Errors of Metabolism Trials Register: 09 October 2009.We also searched PubMed till 01 June 2008.

SELECTION CRITERIA

Randomised controlled trials, both published and unpublished, where a cholesterol-lowering diet in children and adults with familial hypercholesterolaemia has been compared to other forms of dietary treatment or to no dietary intervention were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the trial eligibility and methodological quality and one extracted the data, with independent verification of data extraction by a colleague.

MAIN RESULTS

In the present update, four new trials have been added making eleven trials with a total of 331 participants eligible for inclusion. Only short-term outcomes could be assessed due to the short duration of follow up in the included studies. None of the primary outcomes, (incidence of ischaemic heart disease, number of deaths and age at death) were evaluated in any of the included studies. No significant difference was noted for the majority of secondary outcomes for any of the planned comparisons. However, a significant difference was found only for the following comparison and outcome: total cholesterol levels for the comparison between plant sterols and cholesterol-lowering diet, mean difference 0.70 (95% confidence interval 0.19 to 1.21).

AUTHORS' CONCLUSIONS

No conclusions can be made about the effectiveness of a cholesterol-lowering diet, or any of the other dietary interventions suggested for familial hypercholesterolaemia, due to the lack of adequate data. Large, parallel, randomised controlled trials are needed to investigate the effectiveness of a cholesterol-lowering diet and the addition of omega-3 fatty acids, plant sterols or stanols, soya protein to a cholesterol-lowering diet.

Dietary treatment for familial hypercholesterolaemia

BACKGROUND

Familial hypercholesterolaemia is an inherited disorder characterised by a raised blood cholesterol, the presence of xanthomatosis and premature ischaemic heart disease. The aim of treatment is the reduction of blood LDL cholesterol concentrations in order to reduce the risk of ischaemic heart disease. Current treatment is based on a cholesterol lowering diet alone or in combination with drug therapy. Many of the drugs found to be effective in treating adults with this disease are not licensed for use in children, therefore diet is the main treatment of children with familial hypercholesterolaemia. In addition to the cholesterol-lowering diet, several other dietary interventions have been suggested and consensus has yet to be reached on the most appropriate dietary treatment for children and adults with familial hypercholesterolaemia.

OBJECTIVES

To examine the evidence that in children and adults with familial hypercholesterolaemia, a cholesterol lowering diet is more effective at lowering cholesterol and reducing incidence of ischaemic heart disease than no intervention or than other dietary interventions.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Trials Register, a specialist trials register which comprises references identified from comprehensive electronic database searches, handsearching relevant journals and handsearching abstract books of conference proceedings. Additional studies were identified from handsearching the Journal of Inherited Metabolic Disease (from inception, 1978 to 2000) and from the reference lists of identified studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs), both published and unpublished, where a cholesterol lowering diet in children and adults with familial hypercholesterolaemia has been compared to other forms of dietary treatment or to no dietary intervention. Trials which include patients with familial hypercholesterolaemia alongside patients with non-familial hypercholesterolaemia were only included if the group of familial patients was well defined and the results for these patients were available.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the trial eligibility and methodological quality and one reviewer extracted the data, with independent verification of data extraction by a colleague.

MAIN RESULTS

Only short term outcomes could be assessed in this review due to the length of the five eligible studies. Compliance to treatment, quality of life, mortality and evidence of ischaemic or atheromatous disease were not assessed in the studies identified. No differences were found between the cholesterol-lowering diet and all other diets for all of the short term outcomes assessed.

REVIEWER'S CONCLUSIONS

No conclusions can be made about the effectiveness of the cholesterol-lowering diet, or any of the other dietary interventions suggested for familial hypercholesterolaemia, due to the lack of adequate data. A large, parallel, randomised controlled trial is needed to investigate the effectiveness of the cholesterol-lowering diet and other dietary interventions for FH. It is also possible that data from trials including subjects with both familial and non-familial hypercholesterolaemia could alter the results of future updates of this review and until further evidence is available current dietary treatment of FH should continue to be observed and monitored with care.

A clinical overview of dyslipidemias: treatment strategies

The strong epidemiologic relationship between specific lipoprotein levels (such as elevated low-density lipoprotein cholesterol or decreased high-density lipoprotein cholesterol) and the future development of coronary heart disease has been well documented. Within the past several years, landmark clinical trials have clearly demonstrated that the incidence of coronary heart disease events is reduced when lipoprotein abnormalities are corrected via pharmacologic therapy. These findings have prompted clinicians to become more vigilant with regard to recognition of dyslipidemias and institution of treatment. This review focuses on the more common primary and secondary dyslipidemias and the currently available lipid-lowering therapies for each disorder. Results of recent coronary angiographic trials are discussed, and implications for the medical management of established coronary heart disease are assessed.

Nicotinic acid for the treatment of hyperlipoproteinemia

Nicotinic acid is a water-soluble B-complex vitamin that has been shown, in high doses, to lower total plasma cholesterol (C), LDL-C, and VLDL-triglycerides (Tg), while raising HDL-C in patients with type II, III, IV, and V hyperlipoproteinemia. Its exact mechanism of action is not known, but it appears to lower the production of VLDL in the liver while activating lipoprotein lipase. The drug may also influence the metabolism of HDL-C. The drug is a second or third choice for isolated hypercholesterolemia because of a high incidence of side effects. However, it has a therapeutic advantage as a monotherapy when reduction of both LDL-C and triglycerides are needed in patients with severe combined hyperlipidemia. The drug can be used in combination with other cholesterol-lowering agents to maximize lipid-lowering activity. Nicotinic acid has been associated with a reduced risk of cardiovascular morbidity in clinical trials.

Current approaches to drug therapy for the hypercholesterolemic patient

CAD is a complex disease with multiple etiologies and aggravating events. Yet, elevated plasma cholesterol levels, chiefly in the form of LDL, are essential for the progression of the atherosclerotic lesion. Any total plasma cholesterol level above an ideal of 180 mg/dl (and an LDL cholesterol level of 100 mg/dl) must be considered atherogenic in the presence of other risk factors. In patients at high risk for death from CAD, combined diet and drug therapy should have as a goal the attainment of ideal lipoprotein values. Drug therapies are now available that make it possible to substantially lower elevated LDL levels in almost all patients and even to achieve ideal levels in those at highest risk.

Influence of lovastatin plus gemfibrozil on plasma lipids and lipoproteins in patients with heterozygous familial hypercholesterolemia

We investigated the hypocholesterolemic effects of lovastatin alone and in combination with gemfibrozil on plasma lipids and lipoproteins in 12 adult patients with well-characterized heterozygous familial hypercholesterolemia. Plasma concentrations of low density lipoprotein (LDL) cholesterol decreased from 321 +/- 14 mg/dl on diet only to 207 +/- 8 mg/dl (-35.5%) on single-drug therapy with lovastatin at a dose of 40 mg twice daily, whereas triglyceride concentrations fell by 27.6% (from 145 +/- 20 to 105 +/- 20 mg/dl). Subsequent addition of gemfibrozil at a dose of 600 mg twice daily resulted in a nonsignificant further reduction in LDL cholesterol to 194 +/- 7 mg/dl (-39.6% change from baseline), whereas triglycerides decreased to 80 mg/dl (-44.8%, p less than 0.05 vs. single-drug therapy with lovastatin). Plasma concentrations of high density lipoprotein (HDL) increased slightly during lovastatin and combined drug therapy (from 45 +/- 4 mg/dl at baseline to 46 +/- 4 mg/dl on lovastatin to 48 +/- 4 mg/dl on lovastatin plus gemfibrozil). The response to combination drug therapy in individual patients was heterogeneous and clinically significant decreases in LDL cholesterol concentrations were noted in two of the 12 patients, whereas in three patients LDL cholesterol concentrations increased on the combined drug regimen. One patient developed an asymptomatic increase in creatine kinase on monotherapy with lovastatin and a more pronounced and symptomatic increase during combination drug therapy with lovastatin plus gemfibrozil.(ABSTRACT TRUNCATED AT 250 WORDS)

Intensive combination drug therapy of familial hypercholesterolemia with lovastatin, probucol, and colestipol hydrochloride

Patients with familial hypercholesterolemia (FH) have had a life-long sustained elevation of low-density lipoprotein (LDL) cholesterol levels. Consequently, there is a need to maximally lower their elevated levels, and this usually requires lowering LDL levels more than 50%. Because no single hypolipidemic drug will consistently produce such degrees of lowering, combination drug therapy with two or even three agents is required to produce the desired degree of cholesterol lowering. A prospective trial was designed to determine if combination therapy using three hypolipidemic agents could effectively lower LDL levels in 17 severely affected FH subjects. Colestipol hydrochloride (10 g b.i.d.), probucol (500 mg b.i.d.), and lovastatin (20 or 40 mg b.i.d.) were given to each patient, in varying combinations, over a 25-month period. Lovastatin (40 mg/day) uniformly lowered LDL levels 36%. Probucol lowered LDL only 14% and in a variable manner. The combination of lovastatin and probucol lowered LDL no better than lovastatin alone. Lovastatin plus colestipol lowered LDL 52%; probucol added as a third agent produced no further lowering. Lovastatin (80 mg/day) plus colestipol lowered LDL 56%. Lovastatin increased high-density lipoprotein (HDL) cholesterol levels 6%, whereas probucol decreased HDL 29%. In all patients there was an effective lowering of LDL levels, ranging from 40% to 70%. Thus, lovastatin plus colestipol is an effective hypolipidemic regimen for producing marked decreases in LDL levels in FH subjects. The addition of probucol as a third hypolipidemic agent adds little to the therapeutic regimen as measured by lowering of LDL levels.

Decrease in LDL and increase in HDL concentrations in type II hyperlipoproteinaemic patients on low-dose combination therapy of cholestyramine and Complamin

A low-dose combination of Complamin retard (1 g t.i.d.) and cholestyramine (4 g b.i.d.) was compared with each agent alone in 2 serial open trials without dietary restriction using type IIa and IIb hyperlipoproteinaemic patients. Complamin alone produced decreases in LDL and VLDL cholesterol concentrations (up to 20%) whereas cholestyramine alone produced only a modest reduction in LDL (up to 15%). The combination produced marked, progressive reductions in total cholesterol (up to 35%) and LDL (up to 40%); reductions in VLDL (up to 45%), total triglyceride (up to 60%) and free fatty acids (up to 60%) were found only in type IIb patients. The average increase in HDL-cholesterol from the 2 studies for combination therapy was 35%. No side-effects were reported or measured and compliance was excellent. The results demonstrate the potential of a method of achieving beneficial actions on lipoprotein levels with a well-tolerated therapy.

Mode of action of lipid-lowering drugs

Following the recent demonstration that both cholestyramine and nicotinic acid decrease mortality from coronary heart disease, there is a new enthusiasm for hypolipidaemic therapy. The agents in current use are, however, insufficiently active or are accompanied by unacceptable side effects. An understanding of the mode of action is necessary, both to optimize treatment guidelines (e.g. regarding combination therapy or use in specific subsets of patients) and to develop new agents with preferred actions on rate-limiting steps. A reduction in LDL cholesterol concentration remains the principal desired action, although an elevation in HDL may also be beneficial. The main categories of commercially available agent comprise the anion exchange resins (inhibitors of bile acid absorption); cholesterol absorption inhibitors; fibrates (probably acting by enhancing lipoprotein lipase); and probucol (affecting LDL clearance). The most interesting of the new agents in clinical trials are the beta-hydroxy-beta-methylglutaryl-CoA reductase inhibitors, but other types of agent are at an earlier stage of evaluation, e.g. acyl-CoA: cholesterol acyltransferase inhibitors and peptide cofactors. It is not yet certain whether all the approaches to cholesterol lowering have equal validity, although an effect on biological endpoints is obtained for a variety of agents. Future evaluation will be aided by the implementation of noninvasive methods to quantify atherosclerosis and by the use of simple, 'dry-chemistry', cholesterol assays to screen populations.

Extracranial carotid arterial disease in patients with familial hypercholesterolemia and coronary artery disease treated with colestipol and nicotinic acid

Carotid bifurcation atherosclerosis was demonstrated in 34 of 108 patients with familial hypercholesterolemia and coronary artery disease by B-scan, continuous-wave Doppler sonography, and intravenous digital subtraction angiography. An intensive combined therapy of diet, colestipol, and nicotinic acid was mounted to control the hypercholesterolemia of these patients. Their serial sonographies and digital subtraction angiography were evaluated independently by technical specialists who served as coinvestigators. The data obtained suggest that extracranial arterial disease can develop concurrently with coronary artery disease in a significant proportion of patients with familial hypercholesterolemia, and amaurosis fugax, transient ischemic attack, cerebral infarction, and myocardial infarction did not recur during 58-72 months of control of familial hypercholesterolemia in this series of patients.

Comparison of six pharmacologic regimens for hypercholesterolemia

Six sequential clinical trials were conducted over 5 years to evaluate the safety and efficacy of different treatment regimens for hypercholesterolemia. Of all the study participants, 11 patients were evaluated in all 6 clinical trials using the following regimens: neomycin, neomycin/niacin, cholestyramine, cholestyramine/neomycin, lovastatin and lovastatin/neomycin. All 6 regimens significantly (p less than 0.05) reduced both total and low-density lipoprotein cholesterol concentrations by 25 to 42% from baseline levels. Only neomycin/niacin, cholestyramine and lovastatin significantly increased the high-density lipoprotein (HDL) cholesterol concentration, reducing the total cholesterol/high-density lipoprotein cholesterol ratio to less than 4.7. Thus, all 6 tested regimens were effective in modifying the plasma lipoprotein concentrations in type II hyperlipoproteinemia, but neomycin/niacin, cholestyramine and lovastatin had the most favorable impact. Only lovastatin treatment was free of adverse effects.

Effects of combined probucol-colestipol treatment for familial hypercholesterolemia and coronary artery disease

To evaluate the effect of hypercholesterolemic treatment on coronary artery disease in patients known to be susceptible to disease progression, 44 patients with familial hypercholesterolemia and coronary artery disease were started on a lipid-lowering diet and either probucol (1 g/day) or colestipol (30 g/day). After 5 months of monotherapy, all patients went on a regimen of diet and 2-drug therapy. To date, combination therapy has continued for 3.4 to 4.1 years, and has resulted in the following changes from baseline in mean serum lipid levels: -48.5% in total cholesterol, -53.3% in low density lipoprotein cholesterol, -30.0% in high density lipoprotein cholesterol and +14.5% in triglycerides. The reduction in low density lipoprotein cholesterol apparently improved the clinical status of these patients despite the associated drop in high density lipoprotein cholesterol. In the 19 patients who underwent coronary arteriography before admission to the study, follow-up arteriograms showed that combined treatment stabilized the progression of established lesions and prevented the formation of new ones. Side effects occurred mainly with monotherapy and during the early phase of combination therapy. Reactions included diarrhea, constipation, other vague abdominal symptoms, headache and joint stiffness. In all instances, the side effects gradually subsided after the institution of combination therapy. The combination of probucol and colestipol plus diet appears to be effective in treating most patients with familial hypercholesterolemia.

Contrasting effects of unmodified and time-release forms of niacin on lipoproteins in hyperlipidemic subjects: clues to mechanism of action of niacin

To minimize the cutaneous flushing symptoms associated with niacin use, a time-release capsule form of niacin has been formulated. Thus study compares the effects of time-release niacin with those of unmodified niacin on lipoprotein lipids, including HDL2 and HDL3, apoproteins A-I and A-II, clinical chemistries, symptomatic side effects, and adherence to the medication regimen. Seventy-one primarily hypercholesterolemic subjects were randomized to either unmodified niacin or time-release niacin ad took medication for a six-month period. The two groups were closely matched on anthropomorphic and lipid variables. Adherence to the therapeutic regimen at a dose of 1.5 g/d in the first month of treatment was similar in the two groups. Thereafter, at a dose of 3.0 g/d, adherence was in excess of 90% among subjects taking unmodified niacin but only 64% among those taking time-release niacin, chiefly because of aggravated gastrointestinal symptoms; cutaneous flushing side effects, however, were slightly less common with time-release niacin. At these levels of adherence, LDL cholesterol (C) was reduced 21% by unmodified niacin and 13% by the time release form. Plasma total triglyceride was reduced more with unmodified niacin (27%) than with time-release niacin (8% maximum), and HDL-C and HDL2-C were increased significantly with unmodified niacin (26% and 36%) and were not significantly changed by time-release niacin. Increased to a similar degree on both regimens were HDL3-C (approximately 35%) and apoA-I (approximately 12%). ApoA-II was not affected by either drug regimen.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of combination cholestyramine-neomycin treatment on plasma lipoprotein concentrations in type II hyperlipoproteinemia

Recent prospective clinical trials have established that cholesterol reduction in patients with elevated (upper 90th percentile) concentrations of low-density lipoproteins (LDL) reduces the incidence of myocardial infarction and sudden death. Because the level of protection from these cardiovascular sequelae is directly related to the degree of LDL reduction, combination therapy using different hypolipidemic agents has been used in patients with type II hyperlipoproteinemia (HLP). Neomycin is as effective as cholestyramine in reducing LDL levels and combination neomycin-niacin treatment normalizes the plasma lipoproteins in 92% of patients with type II HLP. Because neomycin could theoretically ameliorate some of the gastrointestinal side effects of cholestyramine in addition to further affecting cholesterol levels, the effects of combination cholestyramine-neomycin treatment on the plasma lipoprotein were assessed in 18 patients with type II HLP in a 9-month clinical trial. Compared with diet-only treatment, cholestyramine reduced total and LDL cholesterol levels by 77 mg/dl (22%) and 78 mg/dl (31%), respectively. In addition to relieving cholestyramine-induced constipation, neomycin further reduced the total cholesterol level by 20 mg/dl (6%). However, this further reduction in total cholesterol concentration was the result of a decrease in the concentration of high-density lipoprotein cholesterol. These findings indicate that combination therapy does not have an additive LDL cholesterol-lowering effect and that neomycin and cholestyramine is not a useful drug combination. In addition, these results illustrate the importance of determining the high-density lipoprotein cholesterol concentration to fully interpret the effects of hypolipidemic treatment.

Effects of hypolipidemic therapy on cholesterol homeostasis in freshly isolated mononuclear cells from patients with heterozygous familial hypercholesterolemia

Freshly isolated mononuclear leukocytes have been reported to show changes in cholesterol synthesis and high-affinity degradation of low-density lipoproteins (LDL) that parallel those that occur in the liver. To examine whether hypolipidemic therapy in patients with heterozygous familial hypercholesterolemia influences cholesterol homeostasis in their mononuclear cells we assessed the effects of colestipol and nicotinic acid (alone and in combination) on the rates of high-affinity 125I-labeled LDL degradation and on the rates of cholesterol and phosphatidylcholine biosynthesis by freshly isolated cells. Rates of 125I-labeled LDL degradation were lower in mononuclear cells from patients with heterozygous familial hypercholesterolemia on no medication (3.1 ng per 4 X 10(6) cells per 5 hr) than in cells from normal control subjects (6.1 ng per 4 X 10(6) cells per 5 hr) and, in the former patients, the values were not significantly affected by therapy with nicotinic acid. In contrast, freshly isolated mononuclear cells from patients receiving colestipol degraded 125I-labeled LDL at near-normal rates (5.0 ng per 4 X 10(6) cells per 5 hr). The rates of cholesterol synthesis were also higher in mononuclear cells isolated from patients treated with colestipol than in cells from untreated patients or from those receiving nicotinic acid; in contrast the rate of synthesis of phosphatidylcholine did not show any consistent changes. Similar results were obtained in a smaller number of patients studied longitudinally, in which colestipol therapy significantly increased rates of cholesterol synthesis and high-affinity degradation of 125I-labeled LDL by freshly isolated mononuclear cells. We conclude that previously observed changes in cholesterol homeostasis in the liver of patients treated with bile acid sequestrants are paralleled by similar changes in freshly isolated mononuclear cells and that these cells offer an accessible model for further studies on how diet and pharmacologic agents influence cellular cholesterol homeostasis in humans.

Combined therapy of niacin, colestipol, and fat-controlled diet in men with coronary bypass. Effect on blood lipids and apolipoproteins

The effects of colestipol (30 grams/day), niacin (7.3 grams/day), and diet on blood lipids and apolipoproteins after one year of therapy are reported. Men selected on the basis of previous coronary artery bypass surgery were randomly assigned to drug or control treatments in an angiographic study of atherosclerosis progression and regression. In 14 men, drugs and diet produced the following changes: Baseline total cholesterol 245 mg/dl, triglyceride 189 mg/dl, and LDL cholesterol 164 mg/dl were decreased by 73 mg/dl (29%), 83 mg/dl (41%) and 69 mg/dl (40%) respectively. Baseline HDL cholesterol, 44 mg/dl was increased 13 mg/dl (33%). Baseline apolipoprotein B, 124 mg/dl and apolipoprotein C-III (heparin precipitate) 5.6 mg/dl were decreased 40 mg/dl (31%) and 2.4 mg/dl (41%) respectively. All these changes are significant, p less than 0.01. Apolipoprotein A-I and apolipoprotein C-III (heparin supernate) were not significantly changed. In the controls, placebo and diet produced no significant decrease in blood lipid or lipoproteins, with the exception that baseline apolipoprotein B, 111 mg/dl increased 18 mg/dl (12%), p less than 0.05.

Ciprofibrate in the therapy of type II hypercholesterolemia. A double-blind trial

The hypolipidemic efficacy of ciprofibrate was evaluated in patients with type II hypercholesterolemia. Patients were randomized to placebo or ciprofibrate (50 mg or 100 mg/day) and, after a 6-week baseline period, received medication for a period of 12 weeks. Blood samples were analyzed every 2 weeks. Twenty patients completed the study (4 on placebo, 7 on 50 mg/day, and 9 on 100 mg/day ciprofibrate). The drug was well tolerated in all patients. Lipid values in the patients on active drug decreased and attained stable values after 4 weeks of treatment. Compared to baseline values, total and LDL cholesterol decreased 11% and 13% on the 50-mg dose whereas HDL increased 8%. Plasma triglyceride fell by 22%. In patients receiving 100 mg ciprofibrate, total and LDL cholesterol fell by 20% (334 leads to 269 mg/dl) and 24% (262 leads to 198 mg/dl), respectively. HDL increased 9.8% (51 leads to 56 mg/dl) and triglyceride decreased by 30% (102 leads to 69 mg/dl). Values in the placebo group remained stable. We conclude that once daily therapy with 100 mg ciprofibrate, is effective in reducing LDL levels in patients with type II hypercholesterolemia (mainly heterozygous FH) and that this decrease is paralleled by small rises in HDL.

Protection of myocardium by the compensatory mechanism of coronary collaterals after total occlusion of major coronary arteries shown in patients with familial hypercholesterolemia

We report 11 in a group of 21 asymptomatic patients with heterozygous familial hypercholesterolemia (FH) and progressive coronary artery disease to evaluate the role of compensatory mechanism(s), especially coronary collaterals, in providing adequate blood supply to the myocardium, following complete occlusion of one or more major coronary arteries. Diet-colestipol-nicotinic acid treatment decreased their plasma total cholesterol and low density lipoprotein cholesterol (mg/dl, mean +/- SEM) from 442.9 +/- 25.8 and 363.0 +/-24.1, respectively, to 231.2 +/- 11.8 and 185.3 +/- 14.2, respectively, for 6 to 9 years. The initially stenotic lesions of these 11 patients slowly progressed to complete occlusion, while the patients remained free of myocardial ischemia or infarction and exhibited no abnormality on 24-hour ambulatory ECG monitoring, exercise stress, and thallium 201 stress tests. We conclude that coronary occlusion can be retarded in FH patients by strenuous hypocholesterolemic therapy to allow the development of compensatory mechanism including coronary collaterals. Apparently, the angiographically visualizable collaterals combined with subendocardial anastomosis can give adequate myocardial blood supply to this series of FH patients following occlusion of one or more of their major coronary arteries.

Treatment of hypercholesterolemia

After discussing the indications for treatment of familial hypercholesterolemia and the importance of a differential diagnosis, the authors describe drug therapy for the disorder with special attention to combined drug regimens. The surgical treatment of hypercholesterolemia and the treatment of homozygous and other forms of hypercholesterolemia are also detailed.