Relation of non-cholesterol sterols to coronary risk factors and carotid intima-media thickness: The Cardiovascular Risk in Young Finns Study

Serum Values of Cholesterol Absorption and Synthesis Biomarkers in Japanese Healthy Subjects: The CACHE Study HEALTHY Analysis

AIM

Blood cholesterol absorption and synthesis biomarkers predict cardiovascular risk. This study aimed to determine the values of serum non-cholesterol sterol markers [lathosterol (Latho), campesterol (Campe), and sitosterol (Sito)] in healthy individuals and factors affecting these markers.

METHODS

The CACHE Consortium compiled clinical data, including serum Latho (cholesterol synthesis marker), and Campe and Sito (cholesterol absorption markers), by a gas chromatography method in 2944 individuals. Healthy subjects were selected by excluding those with prior cardiovascular disease, diabetes mellitus, hypertension, chronic kidney disease, familial hypercholesterolemia, sitosterolemia, current smokers, those with low (＜17 kg/m2) or high (≥ 30 kg/m2) body mass index (BMI), and those with treatment for dyslipidemia or hyperuricemia. Nonlinear regression stratified by sex was used to examine the associations of cholesterol metabolism markers with age, BMI, and serum lipid levels.

RESULTS

Of 479 individuals selected, 59.4% were female; the median age was 48 years in females and 50 years in males. The three markers showed positively skewed distributions, and sex differences were present. Age was associated positively with Latho, inversely with Campe, but not significantly with Sito. BMI was associated positively with Latho, but not significantly with Campe or Sito. High-density lipoprotein cholesterol (HDL-C) was positively associated with Campe and Sito, but not significantly with Latho. Non-HDL-C was positively associated with the three markers.

CONCLUSION

Our study results in the healthy subjects help to interpret the non-cholesterol sterol markers for cardiovascular risk assessment in patients with cardiovascular risk factors.

Plasma Campesterol Is Positively Associated with Carotid Plaques in Asymptomatic Subjects

BACKGROUND

Increased cholesterol absorption and reduced synthesis are processes that have been associated with cardiovascular disease risk in a controversial way. However, most of the studies involving markers of cholesterol synthesis and absorption include conditions, such as obesity, diabetes, dyslipidemia, which can be confounding factors. The present study aimed at investigating the relationships of plasma cholesterol synthesis and absorption markers with cardiovascular disease (CVD) risk factors, cIMT (carotid intima-media thickness), and the presence of carotid plaques in asymptomatic subjects.

METHODS

A cross-sectional study was carried out in 270 asymptomatic individuals and anthropometrical parameters, fasting plasma lipids, glucometabolic profiles, high-sensitivity C-reactive protein (hs-CRP), markers of cholesterol synthesis (desmosterol and lathosterol), absorption (campesterol and sitosterol), cIMT, and the presence of atherosclerotic plaques were analyzed.

RESULTS

Among the selected subjects aged between 19 and 75 years, 51% were females. Age, body mass index, systolic and diastolic blood pressure, total cholesterol, non-HDL-C, triglycerides, glucose, and lathosterol/sitosterol ratios correlated positively with cIMT (p ≤ 0.05). Atherosclerotic plaques were present in 19% of the subjects. A direct association of carotid plaques with campesterol, OR = 1.71 (95% CI = 1.04-2.82, p ≤ 0.05) and inverse associations with both ratios lathosterol/campesterol, OR = 0.29 (CI = 0.11-0.80, p ≤ 0.05) and lathosterol/sitosterol, OR = 0.45 (CI = 0.22-0.95, p ≤ 0.05) were observed in univariate logistic regression analysis.

CONCLUSIONS

The findings suggested that campesterol may be associated with atherosclerotic plaques and the lathosterol/campesterol or sitosterol ratios suggested an inverse association. Furthermore, synthesis and absorption of cholesterol are inverse processes, and the absorption marker, campesterol, may reflect changes in body cholesterol homeostasis with atherogenic potential.

Plasma Non-cholesterol Sterols as Markers of Cholesterol Synthesis and Intestinal Absorption: A Critical Review

Plasma concentrations of phytosterols and non-cholesterol sterol precursors of cholesterol synthesis have been used as markers of intestinal cholesterol absorption and synthesis in inherited and secondary dyslipidemias and in population-based investigations to evaluate the risk for cardiovascular disease, respectively. The method aims at replacing initial research procedures such as the use of stable isotopes associated with fecal steroid balance, which are limited by the high cost and tedious procedures. However, we show in this review that numerous results obtained with serum sterol measurements are contradictory. In this regard, the following points are discussed: 1) how phytosterols relate to atherosclerosis considering that defects in biliary output or in the transport of phytosterols from the intestinal mucosa back into the intestinal lumen provide increased content of phytosterols and other sterols in plasma and tissues, thus not allowing to conclude that their presence in arteries and atheromas represents the etiology of atherosclerosis; 2) serum non-cholesterol sterols as markers of cholesterol synthesis and absorption, such as cholestanol, present discrepant results, rendering them often inadequate to identify cases of coronary artery disease as well as alterations in the whole body cholesterol metabolism; 3) such methods of measurement of cholesterol metabolism are confounded by factors like diabetes mellitus, body weight and other pathologies including considerable hereditary hyperlipidemias biological variabilities that influence the efficiency of synthesis and intestinal absorption of cholesterol.

The coronary artery calcium score is linked to plasma cholesterol synthesis and absorption markers: Brazilian Longitudinal Study of Adult Health

It is controversial whether atherosclerosis is linked to increased intestinal cholesterol absorption or synthesis in humans. The aim of the present study was to relate atherosclerosis to the measurements of plasma markers of cholesterol synthesis (desmosterol, lathosterol) and absorption (campesterol, sitosterol). In healthy male (n=344), non-obese, non-diabetics, belonging to the city of São Paulo branch of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), we measured in plasma these non-cholesterol sterol markers, together with their anthropometric, dietary parameters, traditional atherosclerotic risk factors, and blood chemistry, coronary arterial calcium score (CAC), and ultrasonographically measured common carotid artery intima-media thickness (CCA-IMT). Cases with CAC>zero had the following parameters higher than cases with CAC = zero: age, waist circumference (WC), plasma total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), and non-high density lipoprotein-cholesterol (non HDL-C). Plasma desmosterol and campesterol, duly corrected for TC, age, body mass index (BMI), waist circumference (WC), hypertension, smoking, and the homeostasis model assessment-insulin resistance (HOMA-IR) correlated with CAC, but not with CCA-IMT. The latter related to increased age, BMI, waist circumference (WC), and systolic blood pressure (SBP). Plasma HDL-C concentrations did not define CAC or CCA-IMT degrees, although in relation to the lower tertile of HDL-C in plasma the higher tertile of HDL-C had lower HOMA-IR and concentration of a cholesterol synthesis marker (desmosterol). Present work indicated that increased cholesterol synthesis and absorption represent primary causes of CAD, but not of the common carotid artery atherosclerosis.

Meta-Analysis of Usefulness of Psyllium Fiber as Adjuvant Antilipid Therapy to Enhance Cholesterol Lowering Efficacy of Statins

Statins are usually well-tolerated drugs with a clear dose-dependent efficacy. However, manifestation of statin's side effects also bears a direct relation to higher doses necessary to achieve high impact cholesterol-lowering effects. Nevertheless, the reliance on statin efficacy alone has often left dietary intervention underutilized even though studies have shown a reduction in serum cholesterol levels when dietary fiber intake is increased. In this meta-analysis, we investigated whether the concomitant use of psyllium, a gel-forming viscous soluble fiber, would cause further overall cholesterol lowering in subjects already receiving statins. A systematic review of the medical literature was performed and identified three randomized, controlled clinical studies that evaluated the cholesterol lowering efficacy of statins when given concomitantly with psyllium as a fiber supplement. The duration of the studies ranged from 4 weeks to 12 weeks. The objective of the meta-analysis was to estimate the overall effect of psyllium plus statin versus statin alone. The results of the meta-analysis showed a clinically and statistically significant (p = 0.001) cholesterol lowering advantage for psyllium plus statin combination treatment over a statin alone. Adding psyllium fiber resulted in reductions in low-density lipoprotein-cholesterol equivalent to doubling the statin dose. In conclusion, the data support that psyllium fiber takenbefore meals adds to the efficacy of statins, providing an easy to implement dietary intervention for those who cannot tolerate side effects associated with higher-dose statins.

Influence of heart rate variability and psychosocial factors on carotid stiffness, elasticity and impedance at menopause

BACKGROUND AND AIMS

The risk for cardiovascular diseases (CVD) increases after menopause. Heart rate variability (HRV), a measure of autonomic control, is a strong predictor of CVD. We undertook this study to test the association of ultrasound indices of early carotid atherosclerosis with HRV, symptoms, hormonal conditions, metabolic state, indicators of stress, and psychosocial factors in women at peri- and postmenopause, registering ambulatory R-R interval monitoring.

METHODS

In a cross-sectional design we studied 100 women at peri- and early postmenopause collecting anthropometry, symptoms, stress-related measurements, metabolic variables, cortisol, FSH and estradiol. We evaluated carotid ultrasonographic indices, and HRV was recorded for 4 h calculating time (SDNN, pNN50, rMSSD) and frequency domains (LF, HF, LF/HF) in women according to menopausal stage, estradiol levels, body mass index and waist circumference.

RESULTS

Carotid indices were similar in peri- and postmenopausal women. For HRV measurements, SDNN was increased at postmenopause. Women with estradiol levels <109.2 pmol/L had increased intima-media thickness (IMT), resistive index, and systolic diameter. Using multivariate analysis, we found the associations of IMT positively with non-HDL-cholesterol, resistive index positively with LF-HRV, but negatively with effort/reward imbalance, carotid β stiffness index inversely with estradiol, and arterial distensibility positively with HF-HRV and creatinine concentrations, but negatively with non-HDL-cholesterol.

CONCLUSIONS

Carotid thickness was related mainly with lipid alterations. Indices of early carotid damage were related with various components of HRV as a manifestation of autonomic imbalance, indicating CVD risk. Other factors involved were time since last menses and psychological stress. Low creatinine was associated with diminished carotid distensibility. This suggests that estrogen, lifestyle, behavior and autonomic regulation participate in vascular damage.

Cholesterol metabolism altered and FGF21 levels high after pediatric liver transplantation despite normal serum lipids

Liver transplantation (LT) predisposes to metabolic derangements and increases the risk for cardiovascular disease. We conducted a national cross-sectional study of all pediatric recipients who underwent LT between 1987 and 2007. We measured serum levels of noncholesterol sterols (surrogate markers of cholesterol synthesis and intestinal absorption) and fibroblast growth factor 21 (FGF21) in 49 patients (74% of survivors) at a median of 10 years posttransplant and in 93 controls matched for age and gender. Although serum cholesterol levels were similar in patients and controls, patients displayed increased whole-body synthesis and decreased intestinal absorption of cholesterol compared with controls (lathosterol to cholesterol ratio 129 ± 55 vs. 96 ± 41, respectively, p < 0.001; campesterol to cholesterol ratio 233 ± 91 vs. 316 ± 107, respectively; p < 0.001). Azathioprine (r =-0.383, p = 0.007) and low-dose methylpredisolone (r =-0.492, p < 0.001) were negatively associated with lathosterol/sitosterol ratio reflecting a favorable effect on cholesterol metabolism. FGF21 levels were higher in patients than in controls (248 pg/mL vs. 77 pg/mL, p < 0.001). In healthy controls, FGF21 was associated with cholesterol metabolism, an association missing in LT recipients. Normal serum lipids are achievable in long-term survivors of pediatric LT, but changes in cholesterol metabolism and increased FGF21 levels may explicate later cardiovascular risk.

Patterns of cholesterol metabolism: pathophysiological and therapeutic implications for dyslipidemias and the metabolic syndrome

Investigating cholesterol metabolism, which derives from balancing cholesterol synthesis and absorption, opens new perspectives in the pathogenesis of dyslipidemias and the metabolic syndrome (MS). Cholesterol metabolism is studied by measuring plasma levels of campesterol, sitosterol and cholestanol, that is, plant sterols which are recognised as surrogate cholesterol-absorption markers and lathosterol or squalene, that is, cholesterol precursors, which are considered surrogate cholesterol-synthesis markers. This article presents current knowledge on cholesterol synthesis and absorption, as evaluated by means of cholesterol precursors and plant sterols, and discusses patterns of cholesterol balance in the main forms of primary hyperlipidaemia and MS. Understanding the mechanism(s) underlying these patterns of cholesterol synthesis and absorption will help to predict the response to hypolipidemic treatment, which can then be tailored to ensure the maximum clinical benefit for patients.