New targets for medical treatment of lipid disorders

Effects of intranasal estradiol treatment on serum paraoxonase and lipids in healthy, postmenopausal women

BACKGROUND/AIMS

Serum lipid concentrations worsen after the menopause because of estrogen deficiency, leading to an increased atherogenic pattern. It is known that serum paraoxonase (PON1) activity prevents the development of atherosclerosis. The aim of this cross-sectional study was to observe the effects of intranasal 17beta-estradiol (300 microg/day) on serum PON1 and lipid levels in healthy postmenopausal women.

METHODS

48 healthy, postmenopausal women were enrolled into this cross-sectional study. 28 subjects without an intact uterus and ovaries were using single-dose (300 microg/day) intranasal 17beta-estradiol and 20 subjects with spontaneous natural menopause were not on any hormone therapy. Body mass index (BMI), blood pressure, serum follicle-stimulating hormone, estradiol, fasting glucose, insulin, lipid fractions and PON1 levels were measured. Homeostasis model assessment (HOMA-R) was used to estimate insulin resistance.

RESULTS

The higher estradiol, high-density lipoprotein and salt-stimulated paraoxonase (SSP) levels were observed in intranasal 17beta-estradiol users in comparison with non-users. There were no statistically significant differences in BMI, blood pressures, other lipid fractions, basal paraoxonase, arylesterase, fasting glucose and insulin levels, HOMA-R between the groups. SSP was inversely associated with fasting insulin levels and HOMA-R.

CONCLUSION

These observations may suggest that intranasal 17beta-estradiol does not have harmful effects on the PON1 activity and lipid metabolism.

Possible role of ubiquinone in the treatment of massive hypertriglyceridemia resistant to PUFA and fibrates

OBJECTIVE

To describe the effect of Coenzyme Q10 (CoQ10) (added to either a fibrate, or polyunsaturated fatty acids (PUFA) or association of both) in patients affected by massive hypertriglyceridemia (MHTG) resistant to fibrates and PUFA.

DESIGN

Open, sequential, comparative intervention study.

SETTING

Specialised centres for dyslipidemia management.

SUBJECTS

Fifteen subjects (mean age: 45.1+/-12.5 years) affected by MHTG and hyporesponsive to either fibrates, or PUFA, or fibrates-PUFA association, and 15 age-matched subjects regularly responders to PUFA and fenofibrate treatment.

INTERVENTIONS

Treatment for periods of 6 weeks each with the following consecutive treatments: CoQ10 150 mg/day, PUFA 3000 mg/day, fenofibrate 200 mg/day, PUFA 3000 mg/day+fenofibrate 200 mg/day, PUFA 3000 mg/day+CoQ10 150 mg/day, fenofibrate 200 mg/day+CoQ10 150 mg/day, and finally, fenofibrate 200 mg/day+PUFA 3000 mg/day + CoQ10 150 mg/day.

RESULTS

CoQ10 supplementation did not improve any monitored parameter in the control group except for systolic and diastolic blood pressure, creatinine and Lp(a) plasma levels, both during fenofibrate and/or PUFA treatment. In MHTG group, CoQ10 supplementation significantly improved TG, TC, Lp(a), uric acid and blood pressure during fenofibrate treatment, but only Lp(a) and blood pressure during PUFA treatment. Fenofibrate appeared to have better effect on hsCRP and gamma-GT plasma levels than PUFA. No significant change was observed in any group and under any treatment in regards to homocysteinemia, PAI-1, or t-PA.

CONCLUSION

Even though the mechanism of action through which the effects were obtained is yet to be elucidated, adding CoQ10 to fenofibrate could improve the drug's efficacy in MHTG patients not responding to fenofibrate alone.

Treatment of massive hypertriglyceridemia resistant to PUFA and fibrates: a possible role for the coenzyme Q10?

OBJECTIVE

To describe the effect of CoQ10 (added to either a fibrate, or PUFA or association of both) in patients affected by massive hypertriglyceridemia (MHTG) resistant to fibrates and PUFA.

DESIGN

Open, sequential, comparative intervention study.

SETTING

Specialised centres for dyslipidemia management.

SUBJECTS

15 subjects (mean age: 45.1 +/- 12.5 years) affected by MHTG and hyporesponsive to either fibrates, or PUFA, or fibrates-PUFA association, and 15 age-matched subjects regularly responders to PUFA and fenofibrate treatment.

INTERVENTIONS

Treatment for periods of 6 weeks each with the following consecutive treatments: CoQ10 150 mg/day, PUFA 3000 mg/day, fenofibrate 200 mg/day, PUFA 3000 mg/day + fenofibrate 200 mg/day, PUFA 3000 mg/day + CoQ10 150 mg/day, fenofibrate 200 mg/day + CoQ10 150 mg/day, and finally, fenofibrate 200 mg/day + PUFA 3000 mg/day + CoQ10 150 mg/day.

RESULTS

CoQ10 supplementation improved, in the control group, systolic and diastolic blood pressure, creatinine and Lp(a) plasma levels, both during fenofibrate and/or PUFA treatment. In MHTG group, CoQ10 supplementation significantly improved TG, TC, Lp(a), uric acid and blood pressure during fenofibrate treatment, but only Lp(a) and blood pressure during PUFA treatment. Fenofibrate appeared to have better effect on hsCRP and gamma-GT plasma levels than PUFA. No significant change was observed in any group and under any treatment in regards to homocysteinemia, PAI-1, or t-PA.

CONCLUSION

Even though the mechanism of action through which the effects were obtained is yet to be elucidated, adding CoQ10 to fenofibrate could improve the drug's efficacy in MHTG patients not responding to fenofibrate alone.

Medical lipid-regulating therapy: current evidence, ongoing trials and future developments

Coronary heart disease (CHD) is a major cause of morbidity and mortality worldwide. Elevated low density lipoprotein-cholesterol (LDL-C) and reduced high density lipoprotein-cholesterol (HDL-C) levels are well recognised CHD risk factors, with recent evidence supporting the benefits of intensive LDL-C reduction on CHD risk. Such observations suggest that the most recent National Cholesterol Education Program Adult Treatment Panel III guidelines, with LDL-C targets of 2.6 mmol/L, may result in under-treatment of a significant number of patients and form the basis for the proposed new joint European Societies treatment targets of 2 and 4 mmol/L, respectively, for LDL and total cholesterol. HMG-CoA reductase inhibitors (statins) reduce LDL-C by inhibiting the rate-limiting step in cholesterol biosynthesis and reduced CHD event rates in primary and secondary prevention trials. The magnitude of this effect is not fully accounted for by LDL-C reduction alone and may relate to effects on other lipid parameters such as HDL-C and apolipoproteins B and A-I, as well as additional anti-inflammatory effects. With increasing focus on the benefits of intensive cholesterol reduction new, more efficacious statins are being developed. Rosuvastatin is a potent, hydrophilic enantiomeric statin producing reductions in LDL-C of up to 55%, with about 80% of patients reaching European LDL-C treatment targets at the 10 mg/day dosage. The Heart Protection Study (HPS) demonstrated that LDL-C reduction to levels as low as 1.7 mmol/L was associated with significant clinical benefit in a wide range of high-risk individuals, including patients with type 2 diabetes mellitus, or peripheral and cerebrovascular disease, irrespective of baseline cholesterol levels, with no apparent lower threshold for LDL-C with respect to risk. Various large endpoint trials, including Treating to New Targets (TNT) and Study of Effectiveness of Additional reductions in Cholesterol and Homocysteine (SEARCH) will attempt to further address the issue of optimal LDL-C reduction. At low LDL-C levels, HDL-C becomes an increasingly important risk factor and is the primary lipid abnormality in over half of CHD patients, with the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study set to assess the effect of raising HDL-C on cardiovascular events in patients with low HDL-C and LDL-C levels below 3 mmol/L. A variety of agents are being developed, which affect both LDL-C and HDL-C metabolism, including inhibitors of acyl-coenzyme A-cholesterol acyl transferase, microsomal transfer protein and cholesterol ester transfer protein, as well as specific receptor agonists. Ezetimibe is a selective cholesterol absorption inhibitor, which produces reductions in LDL-C of up to 25 and 60% reduction in chylomicron cholesterol content with a 10 mg/day dosage. A 1 mmol/L reduction in LDL-C results in a 25% reduction in cardiovascular risk, independent of baseline LDL-C levels. Growing evidence supports the concept that lower is better for LDL-C and that increasing HDL-C represents an important therapeutic target. Furthermore, there is growing appreciation of the role of inflammation in atherogenesis. Consequently, increasing numbers of people should receive lipid-regulating therapy with the development of newer agents offering potential mechanisms of optimising lipid profiles and thus risk reduction. In addition, the pleiotropic anti-inflammatory effects of lipid lowering therapy may provide further risk reduction.

Modulateurs du métabolisme du cholestérol et avenir du traitement de l’athérosclérose

Atherosclerosis is a disease characterized by lipid accumulation in the vascular wall leading to myocardial infarction or stroke. Hypercholesterolemia is an important risk factor and current treatments are largely based on cholesterol lowering. In spite of proven efficacy of existing drugs, like statins, cardiovascular diseases still remain the most common cause of death in industrialised countries. Many new molecular targets are being studied to improve atherosclerosis treatment and reduce the number of deaths. The action on these targets could lead to a decrease of blood cholesterol levels or produce a direct anti-atherosclerotic effect on the vascular wall. A cholesterol lowering effect could be achieved by reducing cholesterol synthesis (squalene synthase inhibitors), intestinal cholesterol absorption as well as intestinal and liver lipoprotein secretion (microsomal transfer protein inhibitors, acyl-coenzyme A-cholesterol acyltransferase inhibitors) or by increasing fecal excretion of bile acids (ileal sodium-dependent bile acid transporter inhibitors). An anti-atherosclerotic effect on the vascular wall could be achieved by reducing the inflammation via activation of peroxisome proliferator activated receptors, or, more particularly, could consist of decreased expression of adhesion molecules and chemoattractant proteins. Increasing the adenosine triphosphate-binding cassette A1 protein and inhibiting acyl-coenzyme A :cholesterol acyltransferase 1 activity could slow down formation of foam cells, which are a hallmark of atherosclerosis. Finally, the cholesterol fraction carried by high density lipoproteins, which is inversely correlated to cardiovascular risk, could be increased by cholesterol ester transfer protein inhibitors. All of these new classes of compounds are currently studied by pharmaceutical companies and are in different phases of development (preclinical or clinical).

Decreased total antioxidant status and increased oxidative stress in women with polycystic ovary syndrome may contribute to the risk of cardiovascular disease

OBJECTIVE

To determine oxidative stress by the level of protein carbonyls and total antioxidant status (TAOS), and whether oxidative stress is associated with increased risk of cardiovascular disease in women with polycystic ovary syndrome (PCOS).

DESIGN

Controlled clinical study.

SETTING

University hospital.

PATIENT(S)

Thirty women with PCOS and 31 healthy control women.

INTERVENTION(S)

Biometric measures and blood samples collection.

MAIN OUTCOME MEASURE(S)

C-reactive protein (CRP), lipid fractions, glucose, protein carbonyls, insulin, and other hormone (gonadotropins, androgens) levels and TAOS were measured. The estimate of insulin resistance was calculated by homeostasis model assessment (HOMA-R).

RESULT(S)

The women with PCOS had significantly higher serum fasting insulin, CRP, protein carbonyl levels, HOMA-R, LH levels, and LH/FSH ratios than healthy women. However, TAOS was significantly lower in women with PCOS. TAOS was negatively correlated with fasting insulin, HOMA-R, CRP, and protein carbonyls. Fasting insulin was positively correlated with protein carbonyls. High density lipoprotein (HDL) was inversely associated with fasting insulin, HOMA-R, and protein carbonyls.

CONCLUSION(S)

Increased oxidative stress and decreased antioxidant capacity may contribute to the increased risk of cardiovascular disease in women with PCOS, in addition to known risk factors such as insulin resistance, hypertension, central obesity, and dyslipidemia.