Effect of policosanol on intimal thickening in rabbit cuffed carotid artery

Antiatherosclerotic function of Kokuto, Okinawan noncentrifugal cane sugar

In the present study, we investigated the effect of phenolic compounds (PCs) and policosanol of Kokuto, Okinawan noncentrifugal cane sugar, on the development of atherosclerosis. A total of 67 male Japanese quail were divided into eight dietary groups in trial 1. The dietary groups were fed the atherosclerotic diet (AD) containing 5% corn oil, 2% cholesterol, and 30% sucrose or seven different types of Kokuto. Dietary intakes of Kokuto notably prevented the development of atherosclerosis. Furthermore, there was a significant negative correlation between the serum radical scavenging activity and the degree of atherosclerosis in the dietary groups. In trial 2, a total of 63 Japanese quail were fed AD with sucrose, Kokuto, PC extracts from Kokuto, wax extracts from sugar cane, octacosanol, vitamin C, and vitamin E. As a result, the supplementation of the diet with Kokuto and PCs significantly reduced the development of atherosclerosis as compared with the ingestion of AD with sucrose. In conclusion, these findings suggest that, among various components of Kokuto, PCs play a central role for the prevention of experimental atherosclerosis in Japanese quail.

Protective Effect of Policosanol on Endothelium and Intimal Thickness Induced by Forceps in Rabbits

Policosanol is a cholesterol-lowering drug isolated from sugar cane wax with concomitant antiplatelet effects that prevents lipofundin-induced atherosclerotic lesions in rabbits and rats, including foam cell formation, and also reduces foam cell formation in carrageenan-induced granulomas in rats, while it inhibits proliferation of smooth muscle cells induced in rabbit cuffed artery. This study was undertaken to determine whether policosanol prevents endothelium damage and increase in arterial wall thickness in rabbits with arterial walls damaged with a forceps. Artery forceps were placed over the central artery of the right ear of all rabbits, and each artery was injured eight times. Animals were randomly distributed into four groups: a positive control group treated with Tween 20/H2O vehicle, two groups treated with policosanol (5 and 25 mg/kg, respectively), and a group treated with aspirin (8 mg/kg). Treatments were given for 30 days. Damaged arteries were examined by light and electron (transmission and scanning) microscopy. To evaluate intimal thickening, areas of intima were measured, and a significant reduction in policosanol-treated animals was observed. The endothelial surface, studied with scanning electron microscopy, revealed several types of damage. In control group, the endothelial surface was severely damaged. De-endothelialized areas were reduced in policosanol-treated animals. Platelet adhesion to subendothelium was seen in all animals of the control group, whereas policosanol-treated groups exhibited significantly reduced platelet adhesion. Policosanol also reduced, dose-dependently, the platelet sequestration induced in the damaged vessel wall, partially preventing the reduction in platelet count. It is concluded that policosanol prevents endothelium injury and reduces significantly intimal thickness of rabbit arteries damaged with forceps.

Protective Effect of Policosanol on Atherosclerotic Plaque on Aortas in Monkeys

BACKGROUND

Policosanol is a cholesterol-lowering drug isolated from sugar cane wax with concomitant antiplatelet effects. Previous studies have shown that policosanol prevents lipofundin-induced atherosclerotic lesions in rabbits and rats, including foam cell formation, as well as the development of foam cells in carrageenan-induced granulomas in rats. Policosanol also inhibits smooth muscle cells proliferation induced on rabbit cuffed artery and on forceps-induced arterial wall damage. Furthermore, policosanol administered long term lowered serum cholesterol and prevented the development of atherosclerotic lesions in Macaca arctoides monkeys. The present study was undertaken to determine whether policosanol could change some characteristic features of atherosclerotic lesions, such as macrophage number and immunohistochemical localization of apoA-1 and apoB in aortas of M. arctoides monkeys.

METHODS

Fourteen adult male monkeys weighing 6-10 kg and receiving a low fat, protein-rich diet were randomly distributed in three groups: control group (six monkeys) and two other groups (four monkeys/group) treated with policosanol (2.5 and 25 mg/kg) for 54 weeks. Samples of arteries were examined by light microscopy. Monoclonal antibodies were used to evaluate the presence of macrophage, apoA-1 and apoB.

RESULTS

Policosanol reduced the presence of macrophages and the occurrence of apoB, whereas increased apoA-1 localization in aortic atherosclerotic lesions compared with control monkeys.

CONCLUSIONS

These results suggest the policosanol potential benefit on plaque composition and stability and could explain the protective effects of policosanol on atherosclerosis development.

Effects of policosanol and lovastatin in patients with intermittent claudication: a double-blind comparative pilot study

Policosanol is a cholesterol-lowering drug with concomitant antiplatelet effects. The present study was undertaken to compare the effects of policosanol and lovastatin on patients with moderately severe intermittent claudication. The study had a 4-week baseline step, followed by a 20-week double blinded, randomized treatment period. Twenty-eight patients who met study entry criteria were randomized to policosanol 10 mg or lovastatin 20 mg tablets once daily. Walking distances in a treadmill (constant speed 3.2 km/hr, slope 10 degrees, temperature 25 degrees C) were assessed before and after 20 weeks of treatment. Both groups were similar at randomization. Compared with baseline, policosanol increased significantly (p < 0.01) the initial claudication distance (ICD) from 160.39 +/- 15.82 m to 211.31 +/- 21.48 m (+33.7%) and the absolute claudication distance (ACD) (p < 0.001) from 236.39 +/- 25.44 m to 288.09 +/- 28.47 m (+24.3%); meanwhile both variables remained unchanged after lovastatin therapy. Changes in ICD and ACD were significantly larger in the policosanol than in the lovastatin group (p < 0.01). Policosanol, but not lovastatin, significantly increased (p < 0.05) the ankle/arm index, although between-group differences were not significant. The frequency of patients reporting improvement on quality of life domains was greater in the policosanol than in the lovastatin group. Policosanol significantly (p < 0.001) lowered total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) by 17.5% and 31.0%, respectively, and meanwhile increased (p < 0.01) high-density lipoprotein-cholesterol (HDL-C) levels by 31.5%. Lovastatin reduced (p < 0.01) TC (18.0%), LDL-C (22.6%), and (p < 0.05) triglycerides (9.8%). In addition, policosanol, but not lovastatin, moderately, but significantly, reduced (p < 0.05) fibrinogen levels, so that final values and percent changes in both groups were different (p < 0.01). Treatments were well tolerated. Only 1 lovastatin patient withdrew from the study because of a nonfatal myocardial infarction. Five lovastatin patients, but none from the policosanol group, experienced 6 adverse events (AE) (p < 0.01). The present results indicate that policosanol, but not lovastatin, is a suitable alternative to manage patients with intermittent claudication because of pleiotropic properties beyond its cholesterol-lowering effects.

Policosanol safely down-regulates HMG-CoA reductase - potential as a component of the Esselstyn regimen

Many of the wide-ranging health benefits conferred by statin therapy are mediated, not by reductions in LDL cholesterol, but rather by inhibition of isoprenylation reactions essential to the activation of Rho family GTPases; this may be the mechanism primarily responsible for the favorable impact of statins on risk for ischemic stroke, senile dementia, and fractures, as well as the anti-hypertensive and platelet-stabilizing actions of these drugs. Indeed, the extent of these benefits is such as to suggest that most adults would be wise to take statins; however, owing to the significant expense of statin therapy, as well as to the potential for dangerous side effects that mandates regular physician follow-up, this strategy appears impractical. However, policosanol, a mixture of long-chain aliphatic alcohols extractable from sugar cane wax, has shown cholesterol-lowering potency comparable to that of statins, and yet appears to be devoid of toxic risk. Recent evidence indicates that policosanol down-regulates cellular expression of HMG-CoA reductase, and thus has the potential to suppress isoprenylation reactions much like statins do. Consistent with this possibility, the results of certain clinical and animal studies demonstrate that policosanol has many effects analogous to those of statins that are not likely explained by reductions of LDL cholesterol. However, unlike statins, policosanol does not directly inhibit HMG-CoA reductase, and even in high concentrations it fails to down-regulate this enzyme by more than 50% - thus likely accounting for the safety of this nutraceutical. In light of the fact that policosanol is quite inexpensive and is becoming available as a non-prescription dietary supplement, it may represent a practical resource that could enable the general public to enjoy health benefits comparable to those conferred by statins. In a long-term clinical study enrolling patients with significant symptomatic coronary disease, Esselstyn has demonstrated that a low-fat, whole-food vegan diet, coupled with sufficient statin therapy to maintain serum cholesterol below 150 mg/dL, can stop the progression of coronary disease and virtually eliminate further risk for heart attack. A comparable regimen, in which policosanol is used in place of statins, may represent a practical strategy whereby nearly everyone willing to commit to health-protective eating can either prevent coronary disease, or prevent pre-existing coronary disease from progressing to a life-threatening event.

Policosanol: clinical pharmacology and therapeutic significance of a new lipid-lowering agent

BACKGROUND

Policosanol is a mixture of higher primary aliphatic alcohols isolated from sugar cane wax, whose main component is octacosanol. The mixture has been shown to lower cholesterol in animal models, healthy volunteers, and patients with type II hypercholesterolemia.

METHODS

We reviewed the literature on placebo-controlled lipid-lowering studies using policosanol published in peer-reviewed journals as well as studies investigating its mechanism of action and its clinical pharmacology.

RESULTS

At doses of 10 to 20 mg per day, policosanol lowers total cholesterol by 17% to 21% and low-density lipoprotein (LDL) cholesterol by 21% to 29% and raises high-density lipoprotein cholesterol by 8% to 15%. Because higher doses have not been tested up to now, it cannot be excluded that effectiveness may be even greater. Daily doses of 10 mg of policosanol have been shown to be equally effective in lowering total or LDL cholesterol as the same dose of simvastatin or pravastatin. Triglyceride levels are not influenced by policosanol. At dosages of up to 20 mg per day, policosanol is safe and well tolerated, as studies of >3 years of therapy indicate. There is evidence from in vitro studies that policosanol may inhibit hepatic cholesterol synthesis at a step before mevalonate generation, but direct inhibition of the hydroxy-methylglutaryl-coenzyme A reductase is unlikely. Animal studies suggest that LDL catabolism may be enhanced, possibly through receptor-mediated mechanisms, but the precise mechanism of action is not understood yet. Policosanol has additional beneficial properties such as effects on smooth muscle cell proliferation, platelet aggregation, and LDL peroxidation. Data on efficacy determined by clinical end points such as rates of cardiac events or cardiac mortality are lacking.

CONCLUSIONS

Policosanol seems to be a very promising phytochemical alternative to classic lipid-lowering agents such as the statins and deserves further evaluation.

A comparative study of policosanol vs lovastatin on intimal thickening in rabbit cuffed carotid artery

Policosanol is a cholesterol-lowering drug isolated from sugar cane wax, which acts by inhibiting cholesterol biosynthesis. Previous studies have demonstrated that policosanol inhibited smooth muscle cell (SMC) proliferation in the cuffed carotid artery of the rabbit and in arterial wall damage induced by forceps in the central artery of the ear of rabbits. The present study was undertaken to compare the effects of policosanol and lovastatin on SMC proliferation in the cuffed carotid artery of rabbits. Collars were placed around the left carotid for 7 and 15 days. The contralateral artery was sham operated. We studied eight experimental groups: two controls groups receiving vehicle for 7 and 15 days, respectively, a satellite sham operated control group, four groups treated with policosanol at 5 and 25 mg kg(-1)for 7 and 15 days and a reference group receiving lovastatin at 20 mg kg(-1)for 15 days. Samples of arteries were examined by light and electron microscopy. To evaluate intimal thickening the cross-sectional areas of intima and media were measured. Neointima was significantly reduced in treated animals compared with controls, but the reduction in lovastatin animals was significantly lower than in policosanol-treated groups. The SMC proliferation was studied by the immunohistochemical detection of proliferating cell nuclear antigen and the reduction observed in policosanol-treated rabbits was significantly larger than in lovastatin-treated animals. It is concluded that the protective effect of policosanol against neointima formation in this experimental model was slightly better than that of lovastatin.

Effects of policosanol on postmenopausal women with type II hypercholesterolemia

This randomized, double-blind, placebo-controlled study was conducted to investigate the efficacy, safety and tolerability of policosanol, a cholesterol-lowering drug purified from sugar-cane wax, in postmenopausal women with type II hypercholesterolemia. A total of 244 women who had experienced the menopause and showed elevated serum total cholesterol and low-density lipoprotein cholesterol (LDL-C) levels despite 6 weeks on a standard lipid-lowering diet were randomized to receive placebo or policosanol 5 mg/day for 12 weeks, after which the dose was doubled to 10 mg/day for the next 12 weeks. Policosanol (5 and 10 mg/day) significantly lowered LDL-C levels (17.7% and 25.2%, respectively) and total cholesterol (12.6% and 16.7%, respectively), as well as the ratios of LDL-C to high-density lipoprotein cholesterol (HDL-C) (17.0% and 29.3%, respectively) and total cholesterol to HDL-C (16.7% and 27.2%, respectively), compared to the baseline and placebo; at the same time, policosanol significantly raised HDL-C levels by 16.5% and 29.3%, respectively. The drug was safe and well tolerated. No drug-related adverse events were observed, and even the extent of adverse events was less in the policosanol group than in the placebo group. Four serious adverse events occurred in the placebo group (one myocardial infarction, two cases of hypertensive status and one surgical intervention) compared to none in the policosanol group. In conclusion, policosanol is effective, safe and well tolerated in hypercholesterolemic postmenopausal women.