Long-term prognostic value of LDL-C, HDL-C, lp(a) and TG levels on cardiovascular disease incidence, by body weight status, dietary habits and lipid-lowering treatment: the ATTICA epidemiological cohort study (2002-2012)

BACKGROUND

The link between blood lipids and cardiovascular disease (CVD) is complex. Our aim was to assess the differential effect of blood lipids on CVD risk according to age, sex, body weight, diet quality, use of lipid-lowering drugs and presence of hypercholesterolemia.

METHODS

In this secondary analysis of the ATTICA prospective cohort study, serum blood lipids, i.e., total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG) and liproprotein(a) [Lp(a)], and sociodemographic, anthropometric, lifestyle and clinical parameters were evaluated at baseline (2001/2002) in 2020 CVD-free men and women. CVD incidence was recorded at the 10-year follow-up (2011/2012).

RESULTS

All blood lipids assessed were univariately related to CVD risk; however, associations remained significant only for HDL-C and TG in multivariate models adjusted for age, sex, body mass index, smoking, Mediterranean Diet Score, physical activity, presence of hypercholesterolemia, hypertension and diabetes mellitus, use of lipid-lowering drugs, and family history of CVD [RR per 1 mg/dL (95% CI): 0.983 (0.967, 1.000) and 1.002 (1.001, 1.003), respectively]. In stratified analyses, TC and LDL-C predicted CVD risk in younger subjects, normal-weight subjects, and those not on lipid-lowering drugs, while HDL-C and TG were significant predictors in older subjects, those with low adherence to the Mediterranean diet, and hypercholesterolemic subjects; a significant effect on CVD risk was also observed for TG in males, overweight participants and lipid-lowering medication users and for Lp(a) in older subjects and females (all p ≤ 0.050).

CONCLUSIONS

The impact of blood lipids on CVD risk differs according to several biological, lifestyle and clinical parameters.

Importance of Coagulation Factors as Critical Components of Premature Cardiovascular Disease in Familial Hypercholesterolemia

For almost a century, familial hypercholesterolemia (FH) has been considered a serious disease, causing atherosclerosis, cardiovascular disease, and ischemic stroke. Closely related to this is the widespread acceptance that its cause is greatly increased low-density-lipoprotein cholesterol (LDL-C). However, numerous observations and experiments in this field are in conflict with Bradford Hill’s criteria for causality. For instance, those with FH demonstrate no association between LDL-C and the degree of atherosclerosis; coronary artery calcium (CAC) shows no or an inverse association with LDL-C, and on average, the life span of those with FH is about the same as the surrounding population. Furthermore, no controlled, randomized cholesterol-lowering trial restricted to those with FH has demonstrated a positive outcome. On the other hand, a number of studies suggest that increased thrombogenic factors—either procoagulant or those that lead to high platelet reactivity—may be the primary risk factors in FH. Those individuals who die prematurely have either higher lipoprotein (a) (Lp(a)), higher factor VIII and/or higher fibrinogen compared with those with a normal lifespan, whereas their LDL-C does not differ. Conclusions: Many observational and experimental studies have demonstrated that high LDL-C cannot be the cause of premature cardiovascular mortality among people with FH. The number who die early is also much smaller than expected. Apparently, some individuals with FH may have inherited other, more important risk factors than a high LDL-C. In accordance with this, our review has shown that increased coagulation factors are the commonest cause, but there may be other ones as well.

PCSK9 inhibition, LDL and lipopolysaccharides: a complex and "dangerous" relationship

Literature concerning the causative factors of atherosclerotic cardiovascular disease shows complex and sometimes contrasting evidence. Most guidelines suggest a strategy aimed at lowering circulating low density lipoproteins (LDL) and ApoB lipoprotein levels. The use of statins and of cholesteryl ester transfer protein inhibitors has led to a number of controversial outcomes, generating a certain degree of concern about the real efficacy and especially safety of these drugs. Literature data show that the use of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors results in a dramatic reduction of various markers of lipid metabolism (namely LDL); however, several critical scientific papers have questioned the value, the need and especially the safety of these innovative drugs. LDL are a protective factor against lipopolysaccharides and other microbial derivatives. Similarly, these gram-negative bacteria-derived compounds have been identified as probable culprits of cardiovascular atherogenesis; moreover, lipopolysaccharides increase hepatic synthesis of PCSK9, as defense mechanism. This enzyme modulates LDL receptors level in the liver, as well as in other organs, such as adrenal gland and reproductive organs. Hence, PCSK9 inhibition may influence glucocorticoid secretion and fertility. Lastly, the consequent reduction of circulating LDL may relevantly hindrance immune system and favor lipopolysaccharides diffusion.

LDL-C does not cause cardiovascular disease: a comprehensive review of the current literature

INTRODUCTION

For half a century, a high level of total cholesterol (TC) or low-density lipoprotein cholesterol (LDL-C) has been considered to be the major cause of atherosclerosis and cardiovascular disease (CVD), and statin treatment has been widely promoted for cardiovascular prevention. However, there is an increasing understanding that the mechanisms are more complicated and that statin treatment, in particular when used as primary prevention, is of doubtful benefit. Areas covered: The authors of three large reviews recently published by statin advocates have attempted to validate the current dogma. This article delineates the serious errors in these three reviews as well as other obvious falsifications of the cholesterol hypothesis. Expert commentary: Our search for falsifications of the cholesterol hypothesis confirms that it is unable to satisfy any of the Bradford Hill criteria for causality and that the conclusions of the authors of the three reviews are based on misleading statistics, exclusion of unsuccessful trials and by ignoring numerous contradictory observations.

Changes in plasma cholesterol in mood disorder patients: does treatment make a difference?

OBJECTIVES

To examine the impact of treatment in patients with acute episodes of major depressive (MD) and manic or hypomanic (M/HM) episodes and co-morbid generalized anxiety symptoms, on the total cholesterol blood levels (TC).

METHOD

A consenting series of patients with acute episodes of DSM IV-R confirmed diagnosis of MD or M/H were included. Subjects were treated with antidepressants, mood stabilizers, or both. The Hamilton depression scale (HAM-D21), the modified mania rating scale (MMRS), and the Hamilton anxiety scale (HAM-A) were utilized to evaluate clinical symptoms. Blood samples were drawn for TC estimations after 10 h of fasting on two occasions over time. The first sample was taken before treatment was started, and the second 4 weeks after treatment. The relationship between changes in TC and the severity of psychiatric symptoms, as measured on HAM-D, MMRS, and the HAM-A, were analysed.

RESULTS

56 subjects (34 with MD and 22 with M/HM episodes) completed the study. About 4 weeks after treatment there was a statistically significant increase in the TC in patients with MD versus a significant decrease in patients with M/HM episodes.

CONCLUSION

Our results replicate earlier reports of significant increase in the cholesterol levels in depressed patients after treatment. We report a significant decrease of TC levels in M/HM episodes with treatment. Although the results in previous reports and in our study are statistically significant, their clinical significance requires further examination in longer-term studies.

Inhibition of stress-activated p38 mitogen-activated protein kinase induces low-density lipoprotein receptor expression

We have recently shown that different signal transduction pathways initiated by a variety of agents converge on growth-responsive p42/44MAPK signaling cascade to induce low-density lipoprotein (LDL) receptor expression. Our recent demonstration that stress-activated p38MAPK negatively regulates LDL receptor expression in an isoform-specific manner via modulation of p42/44MAPK cascade represents a new dimension of complexity in the molecular communication that governs LDL receptor expression. The suggested one-way communication between p38MAPK and p42/44MAPK provides a potential mechanism for fine-tuning cellular levels of cholesterol in response to a diverse set of environmental cues, including stress. Cross talk between MAPKs opens new avenues toward understanding a variety of pathogenic processes; this makes them tempting targets for therapeutic interventions in cardiovascular diseases.

Gemfibrozil enhances platelet activity in patients with combined hyperlipoproteinemia

A placebo-controlled crossover study was conducted to evaluate whether lipid-lowering with gemfibrozil (10 to 12 weeks) affects platelet function in vivo at rest and during mental stress in 21 men with combined hyperlipoproteinemia. Gemfibrozil lowered plasma triglycerides and total and VLDL cholesterol (P < .001 for all), whereas HDL cholesterol increased (P < .001). Gemfibrozil increased platelet counts by 18% (P < .001) and, according to filtragometry measurements, enhanced overall (means of rest and stress values) platelet aggregability in vivo (P = .014); this effect was more evident during mental stress (P = .027) than at rest (P = .18). Moreover, the urinary excretion of 11-dehydro-thromboxane-B2 was 54% higher during treatment with gemfibrozil (P < .001), whereas the excretion of beta-thromboglobulin in urine was unaltered. Plasma beta-thromboglobulin tended to be slightly elevated during active treatment (P = .15). Mental stress increased heart rate and catecholamine levels and elevated all cholesterol fractions (P < .01) and plasma beta-thromboglobulin (during placebo, P = .02), but platelet aggregability did not increase significantly. A positive correlation was found between 11-dehydrothromboxane-B2 excretion and LDL cholesterol levels during placebo (r = .62, P = .0057). In conclusion, gemfibrozil has beneficial effects on plasma lipoprotein levels but enhances several aspects of platelet activity in vivo and increases platelet counts. These changes might be prothrombotic and thus adverse for the hyperlipidemic patient. Primary preventive effects of gemfibrozil might be enhanced if a platelet inhibitor such as aspirin is administered with gemfibrozil.