The emerging anti-inflammatory role of HDL-cholesterol, illustrated in cardiovascular disease free population; the ATTICA study

The Role of High-Density Lipoprotein Cholesterol in 2022

PURPOSE OF THE REVIEW

High-density lipoproteins (HDL) are responsible for the transport in plasma of a large fraction of circulating lipids, in part from tissue mobilization. The evaluation of HDL-associated cholesterol (HDL-C) has provided a standard method for assessing cardiovascular (CV) risk, as supported by many contributions on the mechanism of this arterial benefit. The present review article will attempt to investigate novel findings on the role and mechanism of HDL in CV risk determination.

RECENT FINDINGS

The most recent research has been aimed to the understanding of how a raised functional capacity of HDL, rather than elevated levels per se, may be responsible for the postulated CV protection. Markedly elevated HDL-C levels appear instead to be associated to a raised coronary risk, indicative of a U-shaped relationship. While HDL-C reduction is definitely related to a raised CV risk, HDL-C elevations may be linked to non-vascular diseases, such as age-related macular disease. The description of anti-inflammatory, anti-oxidative and anti-infectious properties has indicated potential newer areas for diagnostic and therapeutic approaches. In the last two decades inconclusive data have arisen from clinical trials attempting to increase HDL-C pharmacologically or by way of recombinant protein infusions (most frequently with the mutant A-I Milano); prevention of stent occlusion or heart failure treatment have shown instead significant promise. Targeted clinical studies are still ongoing.

Association of Elevated Levels of Inflammatory Marker High-Sensitivity C-Reactive Protein and Hypertension

Introduction

The correlation between inflammation and vascular disease is widely accepted. High levels of C-reactive protein (CRP) have been shown to play a role in the process of endothelial dysfunction. Hypertension is described as an inflammatory vascular disease, and is 1 of the most commonly encountered diseases in the outpatient setting. We studied the association between the elevated high sensitivity-CRP (hs-CRP) level and hypertension, as well as other comorbid conditions.

Methods

Electronic medical records of 169 adult patients in our internal medicine office were reviewed for hs-CRP levels, and divided into 2 groups: elevated hs-CRP (≥2 mg/L; n = 110) and normal hs-CRP (<2 mg/L; n = 59). Independent T-Test was used to compare the means of continuous variables between the groups if they were normally distributed. Mann Whitney U-Test was used to compare the continuous variables that were non-parametric. Logistic regression was used to compare the dependent and independent variables.

Results

Among subjects with elevated hs-CRP, 58.2% had hypertension while 47.5% of subjects with normal hs-CRP levels had hypertension (P = .182). There were higher frequencies of association of coronary artery disease (CAD), cerebrovascular disease and hypothyroidism in elevated hs-CRP group but the differences were not statistically significant. Mean white blood cell count was statistically higher in elevated hs-CRP group (P < .05), while alcohol use was significantly higher (P < .05) and statin use was higher in the normal hs-CRP group. There was an inverse relationship between HDL-C and hs-CRP.

Conclusions

There was no statistically significant correlation between hs-CRP level and hypertension. Hs-CRP has statistically significant associations between alcohol use, dementia, white blood cell count, and HDL levels. Promising but not statistically significant correlations were observed between hs-CRP and statin therapy, hypothyroidism, coronary artery disease, and cerebrovascular disease.

Inverse relationship between high-density lipoprotein cholesterol raising and high-sensitivity C-reactive protein reduction in older patients treated with lipid-lowering therapy

BACKGROUND

Little is known regarding relationships between high-sensitivity C-reactive protein (hsCRP) and lipoproteins other than low-density lipoprotein cholesterol (LDL-C). High-density lipoprotein (HDL), with both anti-inflammatory and cholesterol-mediating effects, is of particular interest. This exploratory analysis assessed associations between hsCRP and lipids in older (>65 years) patients with moderate and/or high cardiovascular disease risk, before and after treatment with ezetimibe/simvastatin (E/S) or atorvastatin (ATV).

METHODS

An analysis of a multicenter, randomized, double-blind, 12-week study. Correlations were assessed in 1054 patients with both baseline and 12-week hsCRP ≤ 10 mg/L, pooled across doses of E/S (10/20 and 10/40 mg) and ATV (10, 20, and 40 mg), and combined E/S + ATV treatments. Because of multiple comparisons, observed relationships were considered significant only if P values were < .01.

RESULTS

Correlations between baseline levels of hsCRP and either LDL-C, non-HDL-C, or apolipoprotein B were weak and nonsignificant in the E/S, ATV, and E/S + ATV groups. After 12 weeks of treatment, these correlations increased slightly and significantly in all groups, except for LDL-C in the ATV group. HDL-C was significantly but inversely correlated with hsCRP in the ATV and E/S + ATV groups at baseline, and in all groups at 12 weeks. Only with HDL-C did change correlate with change in hsCRP in both the E/S and combined groups.

CONCLUSIONS

Relationships between hsCRP and lipid factors in older patients were weak at baseline and somewhat stronger after treatment. HDL-C was inversely and consistently correlated with baseline and 12-week on-treatment hsCRP and with therapy-induced changes in HDL-C and hsCRP.

Effect of lycopene-enriched olive and argan oils upon lipid serum parameters in Wistar rats

BACKGROUND

Lycopene has the highest antioxidant activity within carotenoids and is an effective free radical scavenger. Virgin olive oil (VOO) and argan oil (AO) contain trace amounts of a wide variety of phytochemicals which have desirable nutritional properties. The present study intended to assess the effect of various dietary VOO and AO in combination with lycopene consumption on serum biochemical parameters, including total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), triglycerides (TGs) and phospholipids, as well as on hepatosomatic index (HSI) of rats.

RESULTS

Results showed that ingestion of VOO and AO diminished TC, LDL-C, TGs and phospholipid levels, whereas the HDL-C levels augmented in all the groups assayed. The enrichment of VOO and AO with lycopene improved the beneficial effects derived from the consumption of both oils on serum biochemical parameters. A decrease in body weight gain and HSI was detected after the consumption of lycopene-enriched oils.

CONCLUSION

These findings suggest that the inclusion of lycopene in VOO and AO may be used as a natural tool to fight against hyperlipidaemic and hypercholesterolaemic-derived disorders.

Markers of Systemic Inflammation and Apo-AI Containing HDL Subpopulations in Women with and without Diabetes

Background. Besides their role in reverse cholesterol transport, HDL particles may affect the atherosclerotic process through the modulation of subclinical inflammation. HDL particles differ in size, composition, and, probably, anti-inflammatory properties. This hypothesis has never been explored in diabetic women, frequently having dysfunctional HDL. The potential relationship between lipid profile, Apo-AI containing HDL subclasses distribution, and common inflammatory markers (hsCRP, IL-6) was examined in 160 coronary heart disease- (CHD-) free women with and without type 2 diabetes. Results. Compared to controls, diabetic women showed lower levels of the atheroprotective large α-1, α-2, and pre-α-1 and higher concentration of the small, lipid-poor α-3 HDL particles (P < 0.05 all); diabetic women also had higher hsCRP and IL-6 serum levels (age- and BMI-adjusted P < 0.001). Overall, HDL subclasses significantly correlated with inflammatory markers: hsCRP inversely correlated with α-1 (P = 0.01) and pre-α-1 (P = 0.003); IL-6 inversely correlated with α-1 (P = 0.003), α-2 (P = 0.004), and pre-α-1 (P = 0.002) and positively with α-3 HDL (P = 0.03). Similar correlations were confirmed at univariate regression analysis. Conclusions. More atheroprotective HDL subclasses are associated with lower levels of inflammatory markers, especially in diabetic women. These data suggest that different HDL subclasses may influence CHD risk also through the modulation of inflammation.

Effects of Hibiscus sabdariffa L. on serum lipids: a systematic review and meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Prevention of cardiovascular disease by modifying its major risk factors, including serum cholesterol levels, is an important strategy. Hibiscus sabdariffa L. has been promoted for reducing cholesterol levels, but its reported impact on cholesterol levels has been inconsistent. The study aimed to assess systematically the evidence and quality of current research on the effect of Hibiscus sabdariffa L. on blood lipids and its adverse effects.

MATERIALS AND METHODS

Electronic databases were searched up to June 2013 for relevant randomised controlled trials (RCTs). Journals and conference proceedings were also searched. The quality of the selected trials was assessed using the Cochrane Risk of Bias Assessment Tool. The efficacy results of similar studies were pooled if they used the same comparator. Outcomes examined were levels of total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides.

RESULTS

Six studies involving 474 subjects met our inclusion criteria. These studies varied in terms of the types of interventions, comparators used, and duration of trials. Overall, Hibiscus sabdariffa L. did not produce any significant effect on any of the outcomes examined, when compared with placebo, black tea or diet. With short-term use it is well tolerated.

CONCLUSIONS

The available evidence from RCTs does not support the efficacy of Hibiscus sabdariffa L. in lowering serum lipids. Further rigorously designed trials with larger sample sizes are warranted to confirm the effects of HS on serum lipids.

Statin-based treatment for cardiovascular risk and non-alcoholic fatty liver disease. Killing two birds with one stone?

Cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD) share common risk factors and may have a parallel course. Statin treatment alone or in combination with other drugs has a substantially beneficial effect on CVD morbidity and mortality. The question was if these regimens were harmful for the liver. Mounting data suggest that statin monotherapy or statin-based treatments are safe in patients with NAFLD and can improve liver tests and liver ultrasonographic evidence of NAFLD. Recent data suggest that statin-based therapies are beneficial to the liver and at the same time reduce CVD morbidity and mortality in patients with NAFLD more than in subjects without it. These findings suggest that with statins we are able to get two birds with one stone.

Risk factors of migraine-related brain white matter hyperintensities: an investigation of 186 patients

Brain white matter hyperintensities are more prevalent in migraine patients than in the general population, but the pathogenesis and the risk factors of these hyperintensities are not fully elucidated. The authors analyzed the routine clinical data of 186 migraine patients who were referred to the Outpatient Headache Department of the Department of Neurology, Medical School, University of Pécs, Hungary between 2007 and 2009: 58 patients with white matter hyperintensities and 128 patients without white matter hyperintensities on 3 T MRI. Significant associations between the presence of white matter hyperintensities and longer disease duration (14.4 vs. 19.9 years, p = 0.004), higher headache frequency (4.1 vs. 5.5 attacks/month, p = 0.017), hyperhomocysteinemia (incidence of hyperintensity is 9/9 = 100%, p = 0.009) and thyroid gland dysfunction (incidence of hyperintensity is 8/14 = 57.1%, p = 0.038) were found. These data support the theory that both the disease duration and the attack frequency have a key role in the formation of migraine-related brain white matter hyperintensities, but the effects of comorbid diseases may also contribute to the development of the hyperintensities.

Dietary, anthropometric, and biochemical determinants of plasma high-density lipoprotein-cholesterol in free-living adults

The level of high-density lipoprotein is thought to be critical in inhibiting lesion formation as well as reducing the lipid load of preexisting atherosclerotic lesions. With the aim of determining the main determinants of plasma HDL-cholesterol (HDL-c) in free-living adults, 997 individuals (52.3 ± 10 years, 67% females) were selected for a descriptive cross-sectional study. The used data corresponded to the baseline obtained from participants clinically selected for a lifestyle modification program. Covariables of clinical, anthropometry, food intake, aerobic fitness, and plasma biochemistry were analyzed against plasma HDL-c either as continuous or categorized variables. After adjustments for age, gender, and BMI the excess of abdominal fat along with high carbohydrate-energy intake and altered plasma triglycerides were the stronger predictors of reduced plasma HDL-c. In conclusion lifestyle interventions aiming to normalize abdominal fatness and plasma triglycerides are recommended to restore normal levels of HDL-c in these free-living adults.

Biological activities of phenolic compounds present in virgin olive oil

The Mediterranean diet is associated with a lower incidence of atherosclerosis, cardiovascular disease, neurodegenerative diseases and certain types of cancer. The apparent health benefits have been partially ascribed to the dietary consumption of virgin olive oil by Mediterranean populations. Much research has focused on the biologically active phenolic compounds naturally present in virgin olive oils to aid in explaining reduced mortality and morbidity experienced by people consuming a traditional Mediterranean diet. Studies (human, animal, in vivo and in vitro) have demonstrated that olive oil phenolic compounds have positive effects on certain physiological parameters, such as plasma lipoproteins, oxidative damage, inflammatory markers, platelet and cellular function, antimicrobial activity and bone health. This paper summarizes current knowledge on the bioavailability and biological activities of olive oil phenolic compounds.

Putative mechanisms of the relationship between obesity and migraine progression

Studies suggest that obesity is associated with migraine progression from an episodic into a chronic form. We discuss putative mechanisms to justify this relationship. Several of the inflammatory mediators that are increased in obese individuals are important in migraine pathophysiology, including interleukins and calcitonin gene-related peptide. Both migraine and obesity are prothrombotic states. Substances that are important in metabolic control are nociceptive at certain levels. Hypothalamic dysfunction in the orexin pathways seems to be a risk factor for both conditions. In addition, we discuss the importance of metabolic syndrome and autonomic dysfunction in modulating the obesity/migraine progression relationship.

Chemistry and health of olive oil phenolics

The Mediterranean diet is associated with a lower incidence of atherosclerosis, cardiovascular disease, and certain types of cancer. The apparent health benefits have been partially attributed to the dietary consumption of virgin olive oil by Mediterranean populations. Most recent interest has focused on the biologically active phenolic compounds naturally present in virgin olive oils. Studies (human, animal, in vivo and in vitro) have shown that olive oil phenolics have positive effects on certain physiological parameters, such as plasma lipoproteins, oxidative damage, inflammatory markers, platelet and cellular function, and antimicrobial activity. Presumably, regular dietary consumption of virgin olive oil containing phenolic compounds manifests in health benefits associated with a Mediterranean diet. This paper summarizes current knowledge on the physiological effects of olive oil phenolics. Moreover, a number of factors have the ability to affect phenolic concentrations in virgin olive oil, so it is of great importance to understand these factors in order to preserve the essential health promoting benefits of olive oil phenolic compounds.

Mediterranean diet and plasma concentration of inflammatory markers in old and very old subjects in the ZINCAGE population study

BACKGROUND

Aging is associated with low-grade elevation of circulating inflammatory markers, leading to increased risk of morbidity and mortality. The Mediterranean diet has been suggested as a determinant of longevity. In the current study, we investigated the impact of the Mediterranean diet on inflammatory status in old subjects.

METHODS

Within the ZINCAGE study, 957 healthy old subjects (>or=60 years old) from five European countries were recruited. Plasma interleukin (IL)-6, IL-8, monocyte chemoattractant protein, tumor necrosis factor-alpha, high-density lipoprotein cholesterol (HDL-C) and erythrocyte sedimentation rate (ESR) were measured. Dietary data were collected applying a food frequency questionnaire and were used to estimate adherence to the Mediterranean diet.

RESULTS

The Italians presented the greatest adherence to the Mediterranean diet, while the Polish the poorest. In females, higher diet score was significantly associated with lower body mass index and ESR and higher HDL-C levels (beta=-0.127, p=0.003; beta=-0.144, p=0.001; beta=0.144, p=0.029, respectively). In males, diet score was negatively associated with IL-8 levels (beta=-0.101, p=0.044). The Mediterranean diet was associated with reduced IL-8 concentrations in Greeks (beta=-0.213, p=0.007).

CONCLUSIONS

There were significant effects of the components of the Mediterranean diet on inflammation markers. The Mediterranean diet score is useful in assessing nutritional influence on immune status.

Association Between Low-Grade Systemic Inflammation and Type 2 Diabetes Mellitus Among Men and Women from the ATTICA Study

AIM

To investigate the relationship between low-grade inflammation and several glycemic indices in a population-based sample of men and women.

METHODS

The ATTICA study is a population-based cohort that randomly enrolled 1514 men and 1528 women (aged >18 years old), stratified by age and gender, from the Greater Athens area, during 2001-2002. Among several characteristics, inflammation markers (high sensitivity C-reactive protein, interleukin-6, tumor necrosis factor-alpha, homocysteine and amyloid A) and glycemic control indices (fasting blood glucose, insulin, HOMA) were measured in the participants.

RESULTS

The prevalence of diabetes was 7.8% in men and 6.0% in women. The prevalence of impaired fasting glucose (IFG) was 21% in men and 12% in women. Diabetic subjects had 57% higher mean levels of C-reactive protein (p < 0.001), 22% higher mean levels of interleukin-6 (p < 0.001) and 60% higher levels of tumor necrosis factor-alpha (p < 0.001) compared to non-diabetic subjects. Homocysteine and serum amyloid A levels did not show significant differences among groups.

CONCLUSION

Our study supports a positive association between low-grade inflammation and diabetes in a population-based sample of men and women without any evidence of cardiovascular disease, which is independent of demographic, clinical and lifestyle characteristics, including physical activity and dietary factors.