Factors associated with low and elevated plasma high density lipoprotein cholesterol and apolipoprotein A-I levels in the Framingham Offspring Study

Sphingolipidomic profile and HDL subfractions in obese dyslipidemic type 2 diabetic patients

PURPOSE

The aim of the study was to investigate changes in serum sphingolipid levels and high density lipoprotein (HDL) subtypes with relation to low-density lipoprotein cholesterol (LDL-C), non-HDL-C and triglyceride (TG) levels in type 2 diabetes mellitus (T2DM) patients.

METHODS

Blood was obtained from 60 patients with T2DM. Levels of sphingosine-1-phosphate (S1P), C16-C24 sphingomyelins (SMs), C16-C24 ceramides (CERs), and C16 CER-1 P were determined by LC-MS/MS. Serum concentrations of cholesterol ester transfer protein (CETP), lecithin-cholesterol acyltransferase (LCAT) and apolipoprotein A-1 (apoA-I) were analyzed by enzyme-linked immunosorbent assay (ELISA). HDL subfraction analysis was performed by Disc polyacrylamide gel electrophoresis.

RESULTS

C16 SM, C24 SM, C24-C16 CER and C16 CER-1 P levels were significantly increased in T2DM patients with LDL-C above 160 mg/dL, compared to those with LDL-C below 100 mg/dL. A significant correlation was observed between C24:C16 SM, C24:C16 CER ratios and LDL-C, non HDL-C levels. Higher serum levels of C24 SM, C24-C18 CER and C24:C16 SM ratio was seen in obese T2DM patients (BMI>30) compared to those with BMI 27-30. Patients with fasting TG levels below 150 mg/dL had significantly increased HDL-large and significantly decreased HDL-small fractions compared to those with fasting TG levels above 150 mg/dL.

CONCLUSION

Obese dyslipidemic T2DM patients had increased levels of serum sphingomyelins, ceramides and HDL-small fractions. The ratio of serum C24:C16 SM, C24:C16 CER and long chain CER levels may be used as diagnostic and prognostic indicators of dyslipidemia in T2DM.

Comparative lipid and uric acid suppressing properties of four common herbs in high fat-induced obese mice with their total phenolic and flavonoid index

Our present study was designed to investigate the comparative anti-obesity efficacy of ethanolic extract of Azadirachta indica A. Juss., Trigonella foenum-graecum L., Allium sativum L. and Zingiber officinale Roscoe in high fat-induced mice with their total phenolic and flavonoid profile. Total phenolic and flavonoid content were determined by Folin–Ciocalteu's and Aluminium chloride UV method respectively. In our study, 55 healthy mice were separated into 11 groups to take their respective treatments. Lipid and uric acid profile were estimated by using the enzymatic colourimetric method. Ethanolic extract of A. indica contained the highest phenolic and flavonoid content. A. indica normal and high fat diet group showed reduced weight gaining tendency than other extract groups. A. indica at a dose of 400 mg/kg body weight significantly (p < 0.001) reduced serum cholesterol (SC), triglyceride (TG), and uric acid (UA) level than other three extracts when compared with the control group. Thus, a considerable correlation was found between serum uric acid reducing potentials of the present experimental extracts with a lipid-lowering profile. Pathological examination revealed that the average weight of liver and kidney were significantly decreased in A. indica normal. Results obtained from the present study it can be concluded that ethanolic extract of A. indica possesses better lipid-lowering efficacy than the other three herbs.

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Ethanolic extract of A. indica contained the highest phenolic and flavonoid content.

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A. indica significant reduced the serum TC, TG, and UA level than other three extracts when compared with the control group.

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The average weight of liver and kidney were significantly decreased in A. indica.

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A. indica possesses better lipid-lowering efficacy than the other three herbs.

Prevalence of low high-density lipoprotein among young adults receiving antiretroviral therapy in Zambia: An opportunity to consider non-communicable diseases in resource-limited settings

Background

With the introduction of effective antiretroviral therapy (ART), people living with HIV (PLWH) are surviving longer and are at risk for developing metabolic abnormalities that contribute to cardiovascular disease (CVD). In Sub-Saharan Africa (SSA), there is a paucity of epidemiological data on lipid profiles among young adults receiving ART. This study aimed to estimate the prevalence of low high-density lipoprotein cholesterol (HDL-c), a cardioprotective lipid class, and whether it differed by age among adults on ART in Livingstone, Zambia.

Methods

From April to December 2019, we conducted a cross-sectional study of 597 PLWH [n = 58 aged 18–24 years (young adults); n = 539 aged ≥25 years (adults)] on ART for ≥6 months. Data collected included demographic and lifestyle information, anthropometrics, viral load (VL), CD4 count, blood pressure, lipid profiles and fasting/random blood glucose. Clinical measures were defined as: low HDL-c [<1.0 mmol/L for men, <1.3 for women], increased waist circumference (WC) [≥94 cm for men, ≥80 cm for women], high triglycerides (TG) [≥1.7 mmol/l], and virological failure (VF) [VL ≥1000 copies/μl]. We used logistic regression to examine the association between age and low HDL-c after adjusting for multiple variables.

Results

Among the young adults, 60% (35/58) were women, median (25^th, 75^th percentile) age 21 years (18, 23), and median time on ART 116 months (60, 144). Among adults, 63% (342/539) were women, median age 46 years (40, 53) and median time on ART 108 months (60, 144). Young adults had a lower CD4 count compared to adults (median, 492 vs. 568 cells/μL, p = 0.010) and higher prevalence of VF (29% vs. 17%, p = 0.016). In young adults, prevalence of low HDL-c was significantly higher than in adults (63 vs. 38%, p<0.001). A high proportion of young adults (75%) and adults (58%) with low HDL-c were on dolutegravir (DTG)-based ART regimens. After adjusting for sex, duration on ART, WC, body mass index, ART regimen, VF, CD4 count, low density lipoprotein cholesterol, blood pressure and smoking, young adults were significantly more likely than adults to have low HDL-c (odds ratio 2.93; 95% confidence interval 1.46–5.86).

Conclusion

Low HDL-c is highly prevalent among young adult with HIV in SSA independent of other risk factors for metabolic derangements. Lipid abnormalities among young PLWH may contribute to the early development of cardiovascular diseases in this population. This highlights the need to consider low HDL-c in the quest to reduce CVD risk among young adults on ART in SSA.

The effectiveness of body age-based intervention in workplace health promotion: Results of a cohort study on 9851 Danish employees

INTRODUCTION

The aging population emphasize the need for effective health promotion interventions. The workplace is a prioritized setting for health promotion to reach widely within a population. Body age can be used as a health-risk estimate and as a motivational tool to change health behavior. In this study we investigate body age-based intervention including motivational interview and its effect on health, when applied to real life workplace health promotion.

MATERIAL AND METHODS

Body age-based intervention was performed in 90 companies on 9851 Danish employees from 2011-2017. Metabolic risk factors were assessed, body age score was determined and an individualized motivational interview was conducted at baseline and follow-up. Change in body age score, single risk factors, smoking habits and metabolic syndrome were analyzed. The body age score is a composite score comprising 11 weighted variables. A body age score ≤ 0 is preferred, as this elicit a younger/healthier or equal body age compared to chronological age.

RESULTS

At 1.3 year follow-up the unhealthiest employees were less likely to participate. Within follow-up participants (39%, n = 3843) body age had improved by a decline in mean body age score of -0.6 and -0.7 years for men and women, respectively (p<0.001). Number of employees with metabolic syndrome had decreased from 646 at baseline to 557 at follow-up (p = 0.005) and 42% of smokers had quit smoking (p<0.001).

CONCLUSION

On the basis of this study, we suggest that body age assessment motivates to participate in workplace health promotion, affect high risk behavior such as smoking thus have potential in public health promotion.

Ethanol-mediated upregulation of APOA1 gene expression in HepG2 cells is independent of de novo lipid biosynthesis

BACKGROUND

Moderate alcohol intake in human increases HDL-cholesterol, and has protective effects against cardiovascular disease (CVD). Although de novo lipid synthesis inhibitors are highly effective in lowering total and LDL-cholesterol they have only modest effects on raising HDL-C. A better understanding of the mechanism of ethanol-mediated HDL-C regulation could suggest new therapeutic approaches for CVD.

METHODS

Human hepatoblastoma (HepG2) and colorectal epithelial adenocarcinoma (Caco-2) cells were incubated in the presence of varying concentrations of ethanol in the culture medium, with or without addition of de novo lipid synthesis (DNLS) inhibitors (atorvastatin and/or TOFA). ApoA1 protein was measured by Western blot, and RNA of lipid pathway genes APOA1, APOC3, APOA4, APOB100, HMGCR, LDLR, and SREBF2 by quantitative RT-PCR. Lipoproteins (VLDL, LDL, and HDL) and lipids were also monitored.

RESULTS

Ethanol stimulated ApoA1 protein (both cytoplasmic and secreted) and APOA1 RNA levels in HepG2 cells in a dose sensitive way, with ~ 50% upregulation at 100 mM ethanol in the medium. The effect was not observed in intestinal-derived Caco-2 cells. DNLS inhibitors did not block the upregulation of ApoA1 RNA by ethanol; TOFA alone produced a modest increase in ApoA1 RNA. Ethanol had no effect on ABCA1 protein levels. Addition of ethanol to the cell medium led to modest increases in de novo synthesis of total cholesterol, cholesteryl esters and triglycerides, and as expected these increases were blocked when the lipid synthesis inhibitors were added. Ethanol stimulated a small increase in HDL and VLDL but not LDL synthesis. Ethanol in the cell medium also induced modest but measurable increases in the RNA of APOC3, APOA4, APOB, LDLR, and HMGCR genes. Unlike APOA1, induction of RNA from APOC3 and APOA4 was also observed in Caco-2 cells as well as HepG2 cells.

CONCLUSION

This study has verified the previously reported upregulation of APOA1 by exposure of HepG2, but not Caco-2 cells, to ethanol in the culture medium. It is shown for the first time that the effect is dependent on RNA polymerase II-mediated transcription, but not on de novo biosynthesis of cholesterol or fatty acids, and therefore is not a generalized metabolic response to ethanol exposure. Some other lipid pathway genes are also modulated by ethanol exposure of cells. The results reported here suggest that the proximal signaling molecule leading to increased APOA1 gene expression in response to ethanol exposure may be free acetate or acetyl-CoA.

TAKE HOME

Upregulation of ApoA1 gene expression in hepatoma cells in culture, upon exposure to moderate ethanol concentrations in the medium, occurs at the level of RNA and is not dependent on new cholesterol or fatty acid synthesis. The primary signaling molecule may be free acetate or acetyl-CoA. These results are important for understanding the mechanism by which moderate alcohol consumption leads to upregulation of serum HDL-cholesterol in humans, and suggests new approaches to targeting HDL as a risk factor for cardiovascular disease.

Genetic and secondary causes of severe HDL deficiency and cardiovascular disease

We assessed secondary and genetic causes of severe HDL deficiency in 258,252 subjects, of whom 370 men (0.33%) and 144 women (0.099%) had HDL cholesterol levels <20 mg/dl. We excluded 206 subjects (40.1%) with significant elevations of triglycerides, C-reactive protein, glycosylated hemoglobin, myeloperoxidase, or liver enzymes and men receiving testosterone. We sequenced 23 lipid-related genes in 201 (65.3%) of 308 eligible subjects. Mutations (23 novel) and selected variants were found at the following gene loci: 1) ABCA1 (26.9%): 2 homozygotes, 7 compound or double heterozygotes, 30 heterozygotes, and 2 homozygotes and 13 heterozygotes with variants rs9282541/p.R230C or rs111292742/c.-279C>G; 2) LCAT (12.4%): 1 homozygote, 3 compound heterozygotes, 13 heterozygotes, and 8 heterozygotes with variant rs4986970/p.S232T; 3) APOA1 (5.0%): 1 homozygote and 9 heterozygotes; and 4) LPL (4.5%): 1 heterozygote and 8 heterozygotes with variant rs268/p.N318S. In addition, 4.5% had other mutations, and 46.8% had no mutations. Atherosclerotic cardiovascular disease (ASCVD) prevalence rates in the ABCA1, LCAT, APOA1, LPL, and mutation-negative groups were 37.0%, 4.0%, 40.0%, 11.1%, and 6.4%, respectively. Severe HDL deficiency is uncommon, with 40.1% having secondary causes and 48.8% of the subjects sequenced having ABCA1, LCAT, APOA1, or LPL mutations or variants, with the highest ASCVD prevalence rates being observed in the ABCA1 and APOA1 groups.

Dietary Strategies and Novel Pharmaceutical Approaches Targeting Serum ApoA-I Metabolism: A Systematic Overview

The incidence of CHD is still increasing, which underscores the need for new preventive and therapeutic approaches to decrease CHD risk. In this respect, increasing apoA-I concentrations may be a promising approach, especially through increasing apoA-I synthesis. This review first provides insight into current knowledge on apoA-I production, clearance, and degradation, followed by a systematic review of dietary and novel pharmacological approaches to target apoA-I metabolism. For this, a systematic search was performed to identify randomized controlled intervention studies that examined effects of whole foods and (non)nutrients on apoA-I metabolism. In addition, novel pharmacological approaches were searched for, which were specifically developed to target apoA-I metabolism. We conclude that both dietary components and pharmacological approaches can be used to increase apoA-I concentrations or functionality. For the dietary components in particular, more knowledge about the underlying mechanisms is necessary, as increasing apoA-I per se does not necessarily translate into a reduced CHD risk.

Relationship between serum uric acid and ischemic stroke in a large type 2 diabetes population in China: A cross-sectional study

OBJECTIVE

To investigate the relationship of serum UA and ischemic stroke in type 2 diabetes patients in China.

METHOD

We examined the above relationship using the data of the project "Comprehensive Research on the Prevention and Control of the Diabetes" (CRPCD) study. A total of 19,442 participants were enrolled in the cross-sectional study. The enrolled participants were divided into quintiles of the serum UA levels with cut off values for two age groups (<60 versus ≥60years). Binary logistic regression analyses were used to evaluate whether the levels of serum UA were independently associated with ischemic stroke in type 2 diabetes.

RESULTS

The serum UA levels were significantly higher in the participants with age≥60years than those with age<60years (P=0.000). In the age group of <60years, the odds ratio for ischemic stroke with type 2 diabetes in quintile 5 over quintile 1 was 2.420 (95% CI, 1.566-3.470) in the unadjusted model and 1.765 (95% CI, 1.097-2.840) after controlling potential confounders. However, the reverse results were observed in the age group of ≥60years. The odds ratio in quintile 4 over quintile 1 in model 3 and model 4 were 0.767 (95% CI, 0.630-0.934) and 0.782 (95% CI, 0.640-0.957).

CONCLUSION

Our results indicated that serum UA levels were independently positively associated with ischemic stroke in patients aged <60years, but the association was U-shaped in patients aged ≥60years.

Cardiovascular disease prevalence and insulin resistance in the Kyushu-Okinawa Population Study and the Framingham Offspring Study

BACKGROUND

Age-adjusted cardiovascular disease (CVD) prevalence rates are significantly lower in Japan than in the United States.

OBJECTIVE

Our aim was to compare CVD risk in participants in Fukuoka and Framingham.

METHODS

We measured glucose, insulin, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), small dense LDL-C, and triglycerides in men and women from Fukuoka (n = 1108), and age (median, 53 years) and gender-matched subjects from Framingham (n = 1101). Blood pressure, body mass index, use of medications, and history of CVD were also assessed.

RESULTS

CVD prevalence rates were more than 6-fold higher in Framingham men and women than their Fukuoka counterparts (P < .001). Median body mass index, LDL-C, insulin levels, and insulin resistance assessment in Fukuoka men and women were significantly (P < .01) lower than in Framingham; however, diabetes prevalence in Fukuoka men was significantly (P < .01) higher than in Framingham men, whereas female rates were similar, as were levels of systolic blood pressure. High-density lipoprotein cholesterol and surprisingly small dense LDL-C levels were significantly (P < .001) higher in Fukuoka than in Framingham. Standard risk factors do not account for the large differences in CVD prevalence rates between the 2 populations, and population differences in insulin resistance may explain some of these differences.

CONCLUSIONS

Our data are consistent with the concept that the CVD prevalence rate in a Japanese population is much lower than those observed in the United States, and that these differences cannot be explained by standard CVD risk factors, but may relate to marked population differences in insulin resistance.

Diagnosis and treatment of high density lipoprotein deficiency

Low serum high density lipoprotein cholesterol level (HDL-C) <40 mg/dL in men and <50 mg/dL in women is a significant independent risk factor for cardiovascular disease (CVD), and is often observed in patients with hypertriglyceridemia, obesity, insulin resistance, and diabetes. Patients with marked deficiency of HDL-C (<20 mg/dL) in the absence of secondary causes are much less common (<1% of the population). These patients may have homozygous, compound heterozygous, or heterozygous defects involving the apolipoprotein (APO)AI, ABCA1, or lecithin:cholesterol acyl transferase genes, associated with apo A-I deficiency, apoA-I variants, Tangier disease , familial lecithin:cholesteryl ester acyltransferase deficiency, and fish eye disease. There is marked variability in laboratory and clinical presentation, and DNA analysis is necessary for diagnosis. These patients can develop premature CVD, neuropathy, kidney failure, neuropathy, hepatosplenomegaly and anemia. Treatment should be directed at optimizing all non-HDL risk factors.

Enhanced atheroprotection and lesion remodelling by targeting the foam cell and increasing plasma cholesterol acceptors

AIMS

Atherosclerosis development can be ameliorated by promoting reverse cholesterol transport (RCT) from arteries. The process involves cholesterol efflux from foam cells to extracellular acceptors such as apolipoprotein A-I (apoA-I) and high-density lipoprotein (HDL) that mediate transport to the liver. Perilipin-2 (PLIN2) is a lipid droplet (LD)-associated protein that in macrophages facilitates cholesterol storage and prevents efflux. We hypothesized that atheroprotection would be enhanced by concurrently targeting PLIN2 to increase the efflux capacity of foam cells and increasing plasma apoA-I and HDL.

METHODS AND RESULTS

PLIN2-knockout and wild-type mice lacking apolipoprotein E (PLIN2(-/-)/apoE(-/-) and PLIN2(+/+)/apoE(-/-)) were treated with a helper-dependent adenoviral vector encoding human apoA-I (HDAd-AI) or with control empty vector. Treatment with HDAd-AI increased hepatic apoA-I production, plasma apoA-I and HDL-cholesterol (HDL-C), and apoA-I deposition in lesions to a similar extent in PLIN2(-/-)/apoE(-/-) and PLIN2(+/+)/apoE(-/-) mice. However, atherosclerosis development at the aortic sinus was considerably lower in HDAd-AI-treated PLIN2(-/-)/apoE(-/-) mice. A more stable lesion phenotype, with increased collagen content, was primarily associated to treatment with HDAd-AI, but was enhanced under PLIN2 deficiency. PLIN2 deficiency and apoA-I cumulatively reduced LDs and cholesterol ester content in cultured macrophages. Neutral lipid in atheroma was significantly reduced in HDAd-AI-treated PLIN2(-/-)/apoE(-/-) mice, and RCT from macrophages to feces was enhanced in PLIN2(-/-) macrophages.

CONCLUSION

These studies demonstrate a mutually beneficial relationship between PLIN2 deficiency and elevated apoA-I/HDL-C in preventing atherosclerosis development. The data support that targeting foam cell components to mobilize cholesterol may be a promising strategy to enhance the atheroprotection of plasma cholesterol acceptors.

Increased plasma monocyte chemoattractant protein-1 levels in patients with isolated low high-density lipoprotein cholesterol

BACKGROUND

High-density lipoprotein cholesterol (HDL-C) inhibits inflammation associated with the development of atherosclerotic plaques. Monocyte chemoattractant protein-1 (MCP-1) contributes to the pathogenesis of atherosclerosis. The aim of this study was to evaluate the relationship between plasma MCP-1 levels and low HDL-C levels in patients without cardiovascular disease (CVD).

METHODS

This study included 55 patients with low HDL-C (≤ 35 mg/dL) and 33 age- and sex-matched control subjects with normal HDL-C (˃ 35 mg/dL). In addition to MCP-1 levels, laboratory parameters associated with inflammation such as neutrophil-lymphocyte ratio (NLR), uric acid and high sensitivity C-reactive protein (hs-CRP) were also evaluated.

RESULTS

HDL-C levels was significantly lower in study group compared to that of the control group (p < 0.001). MCP-1 were prominently higher in the low HDL-C group compared with those of the control group (p < 0.01). NLR, uric acid and hs-CRP levels were also higher in patients with low HDL-C than controls.

CONCLUSION

These findings suggest that elevated plasma MCP-1 levels and inflammation status might be associated with the increased cardiovascular risk in patients with low HDL-C.

Modulation of lipid metabolism by deep-sea water in cultured human liver (HepG2) cells

It has been found that deep-sea water was associated with lower serum lipid in animal model studies. Herein, we investigated whether DSW exerted a hypolipidemic activity and further elucidated how DSW modulated lipid metabolism in HepG2 cells. Preliminary animal studies showed that DSW exhibited potency to decrease serum total cholesterol, triglycerides, and LDL cholesterol, and increase HDL cholesterol, and the hepatic lipid contents were also significantly lower in the DSW group. When DSW was added to HepG2 cells, it decreased the lipid contents of hepatocyte through the activation of AMP-activated protein kinase, thus inhibiting the synthesis of cholesterol and fatty acid. Besides, LDL receptor was upregulated by activation of sterol regulatory element-binding protein-2. In addition, the levels of apolipoprotein AI and cholesterol 7-alpha-hydroxylase were also raised. Our investigation provided mechanisms by which DSW modulated lipid metabolism and indicated that DSW was worthy of further investigation and could be developed as functional drinking water in the prevention and treatment of hypolipidemic and other lifestyle-related diseases.

High-density lipoprotein subfractions and influence of endothelial lipase in a healthy Turkish population: a study in a land of low high-density lipoprotein cholesterol

PURPOSE

Low concentration of high-density lipoprotein (HDL) is prevalent in Turkey. Endothelial lipase (EL) regulates lipoprotein metabolism. Small, lipid-poor HDL particles represent more-efficient cholesterol acceptors than their large, lipid-rich counterparts. The aim of this study was to investigate HDL subfractions and the effect of EL on HDL concentrations in healthy Turkish population.

METHODS

102 healthy subjects were included in the study (mean age 33.6 ± 10.3 years, 42 female). HDL subfractions were assayed by single precipitation method and EL concentrations were measured by competitive enzyme immunoassay.

RESULTS

Mean HDL concentrations were 1.45 ± 0.37 mmol/L in women, 1.10 ± 0.30 mmol/L in men. Small HDL subfraction levels did not differ statistically between < 1 mmol/L and ≥ 1.6 mmol/L total HDL groups. Small HDL was not correlated with EL, low density lipoprotein cholesterol (LDL), triglyceride (TG) and age but positively correlated with total cholesterol and HDL (r = 0.2, p = 0.017; r = 0.2, p = 0.028, respectively). Large HDL was not correlated with age, EL and total cholesterol, and negatively correlated with HDL, LDL, TG (r = - 0.7, p < 0.001; r = - 0.2, p = 0.045; r = - 0.3, p < 0.001, respectively). If subjects were divided into two groups as HDL< 1 mmol/L and HDL > 1.6 mmol/L, mean EL concentrations were 475.83 ± 521.77 nmol/L and 529.71 ± 276.92 nmol/L, respectively (p = 0.086).

CONCLUSION

There were no differences between small HDL concentrations in the HDL low and high groups. Our data did not support EL to be the reason for low HDL in a healthy Turkish population. Our results in a healthy population may serve as a reference for clinical studies on HDL subfractions.

Low High-Density Lipoprotein Cholesterol Is Characterized by Elevated Oxidative Stress

High-density lipoprotein cholesterol (HDL-C) is an independent risk factor for premature atherosclerosis and cardiovascular disease. Plasma HDL exerts potent antioxidant activity. We evaluated parameters associated with oxidative stress in participants with low HDL-C. This study included 32 patients with low HDL-C (≤35 mg/dL) and 33 age- and sex-matched control patients with normal HDL-C (>35 mg/dL). We evaluated clinical and laboratory parameters that are associated with oxidative stress. The oxidative stress index (OSI) levels were significantly higher in the low HDL-C group (3.32 [0.01-13.3] vs 0.74 [0.17-3.55] AU; P < .01) and negatively correlated with HDL-C levels. We suggest that change in OSI and uric acid levels in the study group might indicate increased oxidative status in patients with low HDL-C. This may be associated with increased cardiovascular risk.

Diagnosis and management of familial dyslipoproteinemias

The three major pathways of lipoprotein metabolism provide a superb paradigm to delineate systematically the familial dyslipoproteinemias. Such understanding leads to improved diagnosis and treatment of patients. In the exogenous (intestinal) pathway, defects in LPL, apoC-II, APOA-V, and GPIHBP1 disrupt the catabolism of chylomicrons and hepatic uptake of their remnants, producing very high TG. In the endogenous (hepatic) pathway, six disorders affect the activity of the LDLR and markedly increase LDL. These include FH, FDB, ARH, PCSK9 gain-of-function mutations, sitosterolemia and loss of 7 alpha hydroxylase. Hepatic overproduction of VLDL occurs in FCHL, hyperapoB, LDL subclass pattern B, FDH and syndrome X, often due to insulin resistance and resulting in high TG, elevated small LDL particles and low HDL-C. Defects in APOB-100 and loss-of-function mutations in PCSK9 are associated with low LDL-C, decreased CVD and longevity. An absence of MTP leads to marked reduction in chylomicrons and VLDL, causing abetalipoproteinemia. In the reverse cholesterol pathway, deletions or nonsense mutations in apoA-I or ABCA1 transporter disrupt the formation of the nascent HDL particle. Mutations in LCAT disrupt esterification of cholesterol in nascent HDL by LCAT and apoA-1, and formation of spherical HDL. Mutations in either CETP or SR-B1 and familial high HDL lead to increased large HDL particles, the effect of which on CVD is not resolved. The major goal is to prevent or ameliorate the major complications of many familial dyslipoproteinemias, namely, premature CVD or pancreatitis. Dietary and drug treatment specific for each inherited disorder is reviewed.

Role of serum lipoprotein at the site of iloprost therapy in the treatment of painful bone marrow edema

The authors hypothesized that the emergence of painful bone marrow edema occurs through microembolisms in the bone marrow that may be reflected in elevated plasma parameters of hypofibrinolysis or a disturbance of the lipid metabolism and that treatment with iloprost may lead to a decrease in or normalization of the elevated serum parameters and, therefore, to pain reduction. Twenty-one patients (12 men and 9 women; mean age, 50 years [range, 22-70 years]) with painful bone marrow edema and elevated lipoprotein(a) (Lp[a]) serum values were treated with intravenous iloprost. Before and 6 weeks after iloprost therapy, the serum concentrations of Lp(a), apolipoprotein A1 (ApoA1), and apolipoprotein B (ApoB) were determined. At 6-week follow-up, 17 patients reported complete resolution of their symptoms. For these patients, complete bone marrow edema resolution was observed on magnetic resonance imaging. Four patients reported that their symptoms were either the same or had worsened but had partial bone marrow edema resolution on magnetic resonance imaging. In these patients, Lp(a) values either increased or remained the same. Hence, the total success rate of iloprost treatment was 86% at a mean follow-up of 17 months (range, 3-45 months). Before iloprost therapy, mean ApoA1, ApoB, and Lp(a) values were 159.8, 108.3, and 69.1 mg/dL, respectively. Six weeks after iloprost therapy, mean ApoA1, ApoB, and Lp(a) values decreased to 147.6 (P=.011), 98.4 (P=.042), and 38.3 (P<.001) mg/dL, respectively. The results of this study indicate a possible role of hypofibrinolysis or a disturbance in the lipid metabolism in the emergence of painful bone marrow edema.

HDL cholesterol and cardiovascular outcomes: what is the evidence?

The relationship between low concentrations of high density lipoprotein cholesterol (HDL-C) and heightened risk for cardiovascular (CV) disease has been known for decades. Despite the consistent inverse relationship among epidemiological studies, the linkage between a residual low HDL-C among patients treated with statins and excess cardiovascular risk is less clearly established. Encouraging results from trials using niacin over the past 40 years have not been validated among more recent trials in patients taking contemporary anti-atherosclerotic therapy. Emerging evidence suggests that certain subsets of HDL particles may be more protective and/or more closely associated with CV disease than others, which may impact therapeutic benefits. Ongoing clinical trials will clarify whether raising HDL-C per se directly translates into a reduction in hard CV events. Until those results are available, the clinician is left with only weak evidence to support whether or not to target treatment of HDL-C with pharmacological therapy.

Coagulation abnormalities in osteonecrosis and bone marrow edema syndrome

The aim of this review was to provide information about the variety of thrombophilic and hypofibrinolytic markers that are possible risk factors for the development of osteonecrosis and bone marrow edema syndrome. A total of 48 parameters were identified in 45 studies that included 2163 patients. The most frequently reported laboratory findings included altered serum concentrations of lipoproteins, decreased concentration and function of fibrinolytic agents, increased levels of thrombophilic markers, and several single nucleotide polymorphisms. Despite inhomogeneities in reported parameters, results, patients' collectives, and treatment strategies, these data suggest that coagulation abnormalities may play an important role in the emergence of osteonecrosis and bone marrow edema syndrome.

HDL-C Response Variability to Niacin ER in US Adults

Background. Niacin is the most effective treatment currently available for raising HDL-C levels. Objective. To evaluate if gender and baseline lipid levels have an effect on the HDL-C response of niacin ER and to identify factors that predict response to niacin ER at the 500 mg dose. Material and Methods. The change in HDL-C effect between baseline and follow-up levels was quantified in absolute change as well as dichotomized into high versus low response (high response was defined as an HDL-C effect of >15% increase and low response was HDL-C <5%) in a sample of 834 individuals. Results. Both males and females with low HDL-C levels at baseline exhibited a response to treatment in the multivariate model (males, HDL-C <40 mg/dL: OR = 5.18, 95% CI: 2.36–11.39; females, HDL-C <50 mg/dL: OR = 5.40, 95% CI: 1.84–15.79). There was also a significant difference in the mean HDL-C effect between baseline and follow-up HDL-C levels in the 500 mg niacin ER dose group for both males (mean HDL-C effect = 0.08, P < 0.001) and females (mean HDL-C effect = 0.10, P = 0.019). Conclusion. Baseline HDL-C levels are the biggest predictor of response to niacin ER treatment for both males and females among the factors evaluated.

HDL inflammation and atherosclerosis: current and future perspectives

The role of high-density lipoprotein (HDL) in the genesis and evolution of cardiovascular disease is a topical and interesting issue. Reduced HDL concentrations appear to be unable to efficiently eliminate the cholesterol excess at the vascular wall level, contributing to the onset of the inflammatory response that typically occurs in the pathogenesis of atherosclerosis from its earliest stages. In the last decade, many studies have explored the possibility of reducing cardiovascular risk through modulation of HDL levels, glimpsing new fascinating therapeutic horizons. This review summarizes recent findings on HDL and cardiovascular disease, mainly with an educational objective, considering the biochemical, cellular and molecular aspects of these particles.

Cardiometabolic risk in community-dwelling persons with chronic spinal cord injury

PURPOSE

The purpose of this study was to describe cardiometabolic risk factors and risk clustering in people with spinal cord injury (SCI).

METHODS

This was a cross-sectional study of 121 subjects aged 18 to 73 years (mean, 37 ± 12 years) with chronic, motor complete SCI between C5 and T12. Assessments included demographic, social, and medical history; physical, anthropometric, and blood pressure assessments; fasting serum assays including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides, and hemoglobin A1c; calculated low-density lipoprotein cholesterol (LDL-C); and an oral glucose tolerance test. Framingham risk scores (FRSs) for each subject were calculated on the basis of Third National Cholesterol Education Program Adult Treatment Panel algorithm.

RESULTS

According to FRSs, 90.1%, 8.3%, and 1.7% were classified in the low-, medium-, and high-risk groups, respectively. The most prevalent cardiometabolic risk factors were overweight/obesity (74%), elevated LDL-C (64%), low HDL-C (53%), elevated systolic blood pressure (SBP, 33%), and elevated TC (30%). Stratification by level of injury demonstrated significant differences between paraplegic and tetraplegic participants in SBP (120 vs 99 mm Hg, P = .0001), 2-hour glucose (101.37 vs 137.93 mg/dL, P = .0001), and 2-hour insulin (47.45 vs 94.36 μIU/mL, P = .024). In addition, triglycerides, fasting insulin, body mass index, LDL-C, hemoglobin A1c, and insulin resistance were significantly associated with FRS.

CONCLUSIONS

Ten percent of young people with SCI are at moderate to high risk for long-term hard cardiac events. Overweight/obesity, LDL-C, HDL-C, SBP, and TC were the most prevalent risk factors. Carbohydrate metabolism is preferentially affected in persons suffering from tetraplegia, indicating a need for impairment-specific risk assessment.

Lifestyle changes and 14-year change in high-density lipoprotein cholesterol in a cohort of male physicians

BACKGROUND

Although cross-sectional studies have identified lifestyle factors associated with high-density lipoprotein cholesterol (HDL-C), no studies have examined the association between changes in lifestyle factors and long-term changes in HDL-C.

METHODS

We examined the association between changes in lifestyle factors and changes in HDL-C over a 14-year period in a cohort of 4,168 US male physicians, followed up between 1982 and 1997 and with HDL-C measured at both time points. Using linear regression, we examined the association between HDL-C change and categorized changes in alcohol consumption, physical activity, body mass index (BMI), and smoking, adjusting for age, baseline HDL-C, and other covariates.

RESULTS

Stable BMI of <25 kg/m(2) or BMI reduction from ≥25 to <25 kg/m(2) were associated with increases in HDL-C of 3.1 to 4.7 mg/dL over 14 years. Alcohol consumption of ≥1 drink daily or increase in alcohol consumption from <1 to ≥1 drink daily was associated with increases in HDL-C of 2.4 to 3.3 mg/dL over 14 years. Adopting a sedentary lifestyle was associated with decreases in 14-year decreases in HDL-C.

CONCLUSION

These findings suggest that reductions in BMI and increases in alcohol consumption are associated with 14-year increases in HDL-C, whereas decreases in physical activity are associated with 14-year decreases in HDL-C.

Study comparing the effect of pioglitazone in combination with either metformin or sulphonylureas on lipid profile and glycaemic control in patients with type 2 diabetes (ECLA)

OBJECTIVE

To explore whether the improvement of lipid profile and glycaemic control observed in randomized control trials with pioglitazone (PIO) is replicated under conditions of general clinical practice.

RESEARCH DESIGN AND METHODS

We studied 2388 patients with type 2 diabetes (T2DM) not adequately controlled by monotherapy on either metformin (MET) or sulphonylurea (SU). Addition of a second drug, according to the treating physician's choice, resulted in three groups, PIO + MET, PIO + SU and MET + SU, followed for twelve months, while efficacy and safety parameters were measured at baseline, at six and at twelve months.

RESULTS

A total of 2116 (88.6%) patients completed the study. Diabetic control and lipid profile improved in all three groups, but the improvement was always greater in the two PIO groups. At 12 months PIO + SU and PIO + MET groups compared to SU + MET showed greater increase in HDL cholesterol (8.3% and 9.2 versus 4.3% p < 0.001) and greater decrease in HbA1c (1.53% and 1.46% versus 0.97%, p < 0.001 for both), in triglycerides (20.7% and 21.5% versus 15.2%, p < 0.001) and in LDL cholesterol (15.2% and 14.6% versus 11.3%, p < 0.001 and p < 0.01, respectively). All changes were greater in patients already taking hypolipidaemic drugs. As ECLA was an observational study, the major limitation is the introduction of confounding bias which, however, was accounted for in the statistical analysis.

CONCLUSIONS

Since improvement of both glycaemic control and lipid profile are considered main targets in the management of the diabetic patient, the results of the present study, conducted under conditions of everyday clinical practice, show that pioglitazone may be considered a potential choice for the treatment of type 2 diabetes, when lifestyle and metformin fail.

Adherence to dietary recommendations and risk of metabolic syndrome: Tehran Lipid and Glucose Study

The "Dietary Guidelines for Americans Adherence Index (DGAI) 2005" was developed based on the latest dietary recommendations to assess the contribution of dietary patterns to chronic diseases. The objective of the study was to evaluate the association of dietary patterns as measured by the modified DGAI 2005 with both the prevalence of metabolic syndrome (MetS) and the MetS risk factors. In this population-based cross-sectional study, 2504 adults (1120 men and 1384 women), aged 19 to 70 years, were randomly selected from the third phase of the Tehran Lipid and Glucose Study. Usual dietary intake was assessed using a food frequency questionnaire, and the DGAI score was calculated for all participants. Metabolic syndrome was defined according to Adult Treatment Panel III diagnostic criteria. Generally, mean values for waist circumference, triglyceride, and blood pressure were significantly higher among male compared with female participants (P < .05). Low high-density lipoprotein cholesterol was the most prevalent MetS risk factor among both men (65.4%) and women (72.5%). After mutual adjustment for confounding variables, those in the highest quartile category of DGAI had a 21% lower prevalence of MetS risk factors clustering than those in the lowest quartile (odds ratio [OR], 0.79; confidence interval [CI], 0.63-0.92; P for trend = .02). Being in the highest quartile category of DGAI score was shown to significantly reduce the prevalence of hyperglycemia (OR, 0.64; CI, 0.47-0.86; P for trend < .001), hypertension (OR, 0.76; CI, 0.70-0.93; P for trend = .05), and low high-density lipoprotein cholesterol (OR, 0.69; CI, 0.54-0.94; P for trend < .001). Consuming a diet consistent with new dietary guidelines was associated with lower risk of MetS prevalence and some of its risk factors. Preventive interventions for MetS risk reduction should focus on the overall dietary pattern.

Effects of statins on skeletal muscle: a perspective for physical therapists

Hyperlipidemia, also known as high blood cholesterol, is a cardiovascular health risk that affects more than one third of adults in the United States. Statins are commonly prescribed and successful lipid-lowering medications that reduce the risks associated with cardiovascular disease. The side effects most commonly associated with statin use involve muscle cramping, soreness, fatigue, weakness, and, in rare cases, rapid muscle breakdown that can lead to death. Often, these side effects can become apparent during or after strenuous bouts of exercise. Although the mechanisms by which statins affect muscle performance are not entirely understood, recent research has identified some common causative factors. As musculoskeletal and exercise specialists, physical therapists have a unique opportunity to identify adverse effects related to statin use. The purposes of this perspective article are: (1) to review the metabolism and mechanisms of actions of statins, (2) to discuss the effects of statins on skeletal muscle function, (3) to detail the clinical presentation of statin-induced myopathies, (4) to outline the testing used to diagnose statin-induced myopathies, and (5) to introduce a role for the physical therapist for the screening and detection of suspected statin-induced skeletal muscle myopathy.

Role of the nuclear receptors HNF4 alpha, PPAR alpha, and LXRs in the TNF alpha-mediated inhibition of human apolipoprotein A-I gene expression in HepG2 cells

The expression of the apolipoprotein A-I gene (apoA-I) in hepatocytes is repressed by pro-inflammatory cytokines such as IL-1beta and TNFalpha. In this work, we have demonstrated that treatment of HepG2 human hepatoma cells with chemical inhibitors for JNK, p38 protein kinases, and NFkappaB transcription factor abolishes the TNFalpha-mediated inhibition of human apoA-I gene expression in HepG2 cells. In addition, we have shown that TNFalpha decreases also the rate of secretion of apoA-I protein by HepG2 cells, and this effect depends on JNK and p38, but not on NFkappaB and MEK1/2 signaling pathways. The inhibitory effect of TNFalpha has been found to be mediated by the hepatic enhancer of the apoA-I gene. The decrease in the level of human apoA-I gene expression under the impact of TNFalpha appears to be partly mediated by the inhibition of HNF4alpha and PPARalpha gene expression. Treatment of HepG2 cells with PPARalpha antagonist (MK886) or LXR agonist (TO901317) abolishes the TNFalpha-mediated decrease in the level of apoA-I gene expression. PPARalpha agonist (WY-14643) abolishes the negative effect of TNFalpha on apoA-I gene expression in the case of simultaneous inhibition of MEK1/2, although neither inhibition of MEK1/2 nor addition of WY-14643 leads to the blocking of the TNFalpha-mediated decrease in the level of apoA-I gene expression individually. The ligand-dependent regulation of apoA-I gene expression by PPARalpha appears to be affected by the TNFalpha-mediated activation of MEK1/2 kinases, probably through PPARalpha phosphorylation. Treatment of HepG2 cells with PPARalpha and LXR synthetic agonists also blocks the inhibition of apoA-I protein secretion in HepG2 cells under the impact of TNFalpha. A chromatin immunoprecipitation assay demonstrates that TNFalpha leads to a 2-fold decrease in the level of PPARalpha binding with the apoA-I gene hepatic enhancer. At the same time, the level of LXRbeta binding with the apoA-I gene hepatic enhancer is increased 3-fold under the impact of TNFalpha. These results suggest that nuclear receptors HNF4alpha, PPARalpha, and LXRs are involved in the TNFalpha-mediated downregulation of human apoA-I gene expression and apoA-I protein secretion in HepG2 cells.

Association of polymorphisms in genes involved in lipoprotein metabolism with plasma concentrations of remnant lipoproteins and HDL subpopulations before and after hormone therapy in postmenopausal women

OBJECTIVE

A high degree of inter-individual variability in plasma lipid level response to hormone therapy (HT) has been reported. Variations in the oestrogen receptor alpha gene (ESR1) and in genes involved in lipid metabolism may explain some of the variability in response to HT. Subjects Postmenopausal Caucasian women (n = 208) participating in a placebo-controlled randomized trial of 3.2 years of hormone therapy (HT).

METHODS

Plasma triglyceride (TG), remnant lipoprotein cholesterol (RLP-C), and high-density lipoprotein cholesterol (HDL-C) levels and HDL subpopulations were assessed at baseline and at follow up. Single nucleotide polymorphisms (SNPs) in ESR1 and in the ATP binding cassette A1 (ABCA1), cholesteryl ester transfer protein (CETP), hepatic lipase (LIPC), lipoprotein lipase (LPL), and scavenger receptor class B type I (SRB1) genes were assessed for their association with baseline plasma levels and HT-related changes in levels of RLP-C and HDL subpopulations.

RESULTS

Carriers of the ESR1 PvuII or IVS1-1505 variants had lower plasma TG concentrations and higher plasma HDL-C and alpha-1 and prealpha-1 HDL particle levels at baseline and showed greater increases in HDL-C, apo A-I and alpha-1 particle levels after HT than wild-type carriers. Carriers of the N291S and D9N variants in the LPL gene had significantly higher remnant lipoproteins and lower alpha-2 HDL particle levels at baseline. The CETP TaqIB SNP was a significant determinant of baseline plasma HDL-C and HDL subpopulation profile.

CONCLUSIONS

Single nucleotide polymorphisms in ESR1, CETP and LPL had significant effects on baseline plasma levels of TG-rich and HDL subpopulations. With the exception of ESR1 SNPs, variation in genes involved in lipid metabolism has a very modest effect on lipoprotein response to HT.

Safety and tolerability of dalcetrapib (RO4607381/JTT-705): results from a 48-week trial

Aims

Co-primary objectives were to evaluate dalcetrapib (JTT-705/RO4607381), which targets cholesteryl ester transfer protein (CETP), effects on high-density lipoprotein cholesterol (HDL-C) in participants with coronary heart disease or risk equivalents and to evaluate potential changes in mesenteric lymph nodes.

Methods and results

Double-blind trial with participants randomized (2:1) to dalcetrapib 900 mg/day (higher than 600 mg phase III dose) or placebo, both with atorvastatin, for 24 weeks (n = 135; one without post-baseline efficacy data was excluded from intent-to-treat population); a subset continued for 24-week extension (n = 77). Lipid changes and safety parameters were assessed. Mesenteric lymph nodes were evaluated by magnetic resonance imaging. Dalcetrapib increased HDL-C (33.4%, Week 24; 33.8%, Week 48), decreased CETP activity (–53.5%, Week 24; –56.5%, Week 48), and increased apolipoprotein A-I (11.4%, Week 24; 16.4%, Week 48). Dalcetrapib showed no clinically relevant differences vs. placebo in adverse events, laboratory parameters including aldosterone, electrocardiograms, and vital signs including blood pressure (BP). Dalcetrapib had no measurable, clinically relevant effect on lymph node size.

Conclusion

Dalcetrapib 900 mg administered for up to 48 weeks showed no clinically relevant changes in lymph nodes, BP, or other safety parameters. Dalcetrapib effectively increased HDL-C over 48 weeks of treatment.

Prevenção primária de doenças cardiovasculares na obesidade infantojuvenil: efeito anti-inflamatório do exercício físico

A pandemia da obesidade juvenil e do sedentarismo está relacionada com o maior risco de doenças cardiovasculares no futuro. Ambas com fisiopatologia inflamatória, essas condições têm atraído significativa atenção científica. O início dos eventos que agridem o endotélio vascular pode ocorrer na infância, porém, sinais clínicos da aterosclerose geralmente só aparecem na fase adulta. O tecido adiposo é hoje reconhecido por seu papel ativo, induzindo a produção de citocinas pró e anti-inflamatórias, como o fator de necrose tumoral-alfa, as interleucinas 1, 6 e 10, a proteína C-reativa e outras. Há várias evidências de que os níveis sanguíneos dessas citocinas se encontram mais altos em indivíduos com excesso de peso, inclusive crianças e adolescentes. A prevenção precoce, desde a infância, apresenta-se como a melhor maneira de evitar os danos da obesidade na fase adulta, enquanto o potencial da prática regular de exercícios físicos tem se mostrado surpreendente. Sua ação anti-inflamatória se manifesta através de menores concentrações séricas de interleucina 6, de proteína C-reativa e leptina, além de aumentos na adiponectina. Observa-se escassez de estudos randomizados e controlados avaliando as relações entre obesidade, inflamação e exercícios para a população jovem. Com resultados às vezes controversos, a maioria das conclusões é procedentede estudos com adultos. O objetivo desta revisão é avaliar o papel anti-inflamatório, e assim cardioprotetor, da atividade física regular na obesidade infantojuvenil.

A single-center, open-label, one-sequence study of dalcetrapib coadministered with ketoconazole, and an in vitro study of the S-methyl metabolite of dalcetrapib

BACKGROUND

Dalcetrapib (RO4607381/JTT-705) is currently under clinical investigation for the prevention of cardiovascular events. It inhibits the activity of cholesteryl ester transfer protein and has been reported to increase levels of high-density lipoprotein cholesterol.

OBJECTIVE

Because dalcetrapib is likely to be coadministered with agents that inhibit the cytochrome P450 (CYP) 3A4 isozyme, this study aimed to determine the effect of ketoconazole, a strong CYP3A4 inhibitor, on the pharmacokinetics of dalcetrapib.

METHODS

An open-label, 1-sequence study was conducted in 2 cohorts of healthy, nonsmoking male volunteers aged 18 through 65 years, with a body mass index of 18 to 32 kg/m(2). The first cohort received dalcetrapib 600 mg on days 1 and 7 and ketoconazole 400 mg on days 2 through 7, and, based on the results of a planned interim analysis, the second cohort received dalcetrapib 900 mg alone on days 1 and 7 and ketoconazole on days 2 through 7. Pharmacokinetic and safety parameters were assessed at specific times throughout the study. To confirm CYP involvement in the metabolism of the inactive metabolite dalcetrapib-S-methyl, in vitro studies were performed using human liver microsomes and recombinantly expressed CYP isoforms.

RESULTS

Of the 26 participants, 96% were white, with a mean age of 38.1 years and a mean weight of 78.6 kg. In the in vivo portion of the study, coadministration of ketoconazole with dalcetrapib 600 mg had no significant effect on any pharmacokinetic parameter of dalcetrapib. Coadministration of ketoconazole with dalcetrapib 900 mg was associated with significant decreases in the dalcetrapib C(max) (-23%; P = 0.002) and AUC(0-infinity) (-18%; P = 0.001) and a significant increase in oral clearance (22%; P = 0.001). Significant increases in the C(max) (P = 0.001) and AUC(0-infinity) (P < 0.001) of dalcetrapib-S-methyl were observed with coadministration of ketoconazole. The combination was generally well tolerated, with 32 of 35 adverse events (91.4%) being mild in intensity. The most frequent adverse events were headache (6/26 [23.1%] in the ketoconazole group; 4/18 [22.2%] in the group receiving dalcetrapib 900 mg plus ketoconazole) and diarrhea (4/26 [15.4%] in the ketoconazole group; 2/18 [11.1%] in the group receiving dalcetrapib 900 mg plus ketoconazole). The in vitro studies confirmed the involvement of CYP3A in the metabolism of dalcetrapib-S-methyl.

CONCLUSIONS

In this clinical study in healthy male volunteers, coadministration of dalcetrapib 600 mg with the CYP3A4 inhibitor ketoconazole was not associated with any significant changes in the pharmacokinetic parameters of the parent compound. Coadministration of dalcetrapib 900 mg with ketoconazole was associated with significant decreases in the dalcetrapib C(max) and AUC, contrary to the increases that would be expected if dalcetrapib were a substrate for CYP3A4. The combination of dalcetrapib and ketoconazole was generally well tolerated.

Differentiated CaCo-2 cells as an in-vitro model to evaluate de-novo apolipoprotein A-I production in the small intestine

BACKGROUND

Increasing HDL cholesterol concentrations by stimulating de-novo apolipoprotein A-I (apoA-I) production in the liver and/or in the small intestine is a potential strategy to reduce coronary heart disease risk. Although there is quite some knowledge concerning regulatory effects in the liver, less is known concerning potential agents that could elevate de-novo apoA-I production in the small intestine.

METHODS

Therefore, we compared side-by-side effects of various peroxisome proliferator-activated receptor (PPAR)alpha, PPARgamma, retinoid-X-receptor alpha, and farnesoid-X-receptor agonists on de-novo apoA-I production in differentiated CaCo-2 and HepG2 cells.

RESULTS

For PPARa agonists, we showed that GW7647 elevated apoA-I concentrations in the medium of both cell models, whereas WY14643 elevated only de-novo apoA-I concentrations in differentiated CaCo-2 cells. Unexpectedly, fenofibric acid lowered apoA-I medium concentrations in both cell lines, which could not be explained by a lack of PPAR transactivation or a lack of retinoid-X-receptor a activation. For farnesoid-X-receptor agonists, chenodeoxycholic acid strongly reduced apoA-I concentrations both in differentiated CaCo-2 and HepG2 cells, whereas GW4064 and taurocholate only lowered apoA-I in CaCo-2 cells (GW4064) or in HepG2 cells (taurocholate). However, overall effects of all individual components on apoA-I production in differentiated CaCo-2 and HepG2 cells were highly correlated (r = 0.68; P = 0.037; N=9).

CONCLUSION

We conclude that differentiated CaCo-2 cells are suitable models to study de-novo small intestinal apoA-I production in vitro enabling the possibility to screen for potential bioactive dietary components. This cell model may also determine small-intestinal-specific effects, as some discrepancy was found between both cell models.

The relationships of ABCB1 3435C>T and CYP2B6 516G>T with high-density lipoprotein cholesterol in HIV-infected patients receiving Efavirenz

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are associated with a favorable increase in high-density lipoprotein cholesterol (HDL-c) level. Isolated studies have found a direct correlation between efavirenz (EFV) exposure and HDL-c level changes. Here we explore the impact that drug disposition variants associated with EFV exposure have on changes in HDL-c level. Seventy-six patients on first-line EFV-based regimens were genotyped for CYP2B6 516G>T and ABCB1 3435C>T. There was a 37% increase (+0.32 mmol/l, P < 0.001) in mean HDL-c level over 48 weeks, and this was univariately associated with gender (male +0.26 mmol/l, female +0.55 mmol/l; P = 0.03), ABCB1 3435C>T (CC +0.26 mmol/l, CT +0.16 mmol/l, TT +0.54 mmol/l; P(ANOVA) = 0.003) and CYP2B6 516 G>T (GG +0.27 mmol/l, GT +0.29 mmol/l, TT +0.72 mmol/l; P(ANOVA) = 0.08). There was a significant association between the cumulative number of predictive genotypes (CYP2B6 516TT or ABCB1 3435TT) and mean HDL-c level change: (group 0 +0.20 mmol/l, group 1 +0.47 mmol/l, group 2 +1.00 mmol/l; P(ANOVA) < 0.0001). These findings need to be validated in independent cohorts.

Common variants in the ATP-binding cassette transporter 1 gene with decreased HDL-cholesterol levels and coronary artery disease

BACKGROUND

Our aim was to determine whether the common variants within the coding sequence of ABCA1 gene affects low plasma high-density lipoprotein cholesterol (HDL-C) levels in Turkish patients with coronary artery disease (CAD). The study group was composed of 552 CAD patients, of which 251 had HDL-C levels < or =40 mg/dL, and 301 had HDL-C levels >40 mg/dL.

METHODS

PCR-RFLP was used to determine the A2589G and G3456C DNA polymorphisms of the ABCA1 gene. The study group was analyzed for potential clinical predictors of low HDL-C.

RESULTS

The GG variant of the ABCA1 gene A2589G polymorphism was found in 3.6% patients within the HDL-C < or =40 mg/dL group and in 4% of HDL-C levels >40 mg/dL group. Frequency distributions of the A2589G genotypes were not found to differ significantly among groups. The CC genotype of the G3456C polymorphism was found in 6.8% of HDL-C < or =40 mg/dL group and in 11.6% individuals of the HDL-C levels >40 mg/dL group. Frequency distributions of the G3456G genotypes were not significantly different among groups. The A2589G genotypes were not found to be effective over the analyzed lipid parameters. Among G3456C genotypes, in CAD patients with HDL-C < or =40 mg/dL the low-density lipoprotein (LDL-C) levels were elevated, whereas HDL-C levels decreased in CC genotype carriers compared to GG and GC.

CONCLUSIONS

No significant association was found between cardiovascular endpoints and ABCA1 gene A2589G and G3456C genotypes in this study population.