Hubert Scharnagl

Independent Association of Low Serum 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D Levels With All-Cause and Cardiovascular Mortality

BACKGROUND In cross-sectional studies, low serum levels of 25-hydroxyvitamin D are associated with higher prevalence of cardiovascular risk factors and disease. This study aimed to determine whether endogenous 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels are related to all-cause and cardiovascular mortality. METHODS Prospective cohort study of 3258 consecutive male and female patients (mean [SD] age, 62 [10] years) scheduled for coronary angiography at a single tertiary center. We formed quartiles according to 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels within each month of blood drawings. The main outcome measures were all-cause and cardiovascular deaths. RESULTS During a median follow-up period of 7.7 years, 737 patients (22.6%) died, including 463 deaths from cardiovascular causes. Multivariate-adjusted hazard ratios (HRs) for patients in the lower two 25-hydroxyvitamin D quartiles (median, 7.6 and 13.3 ng/mL [to convert 25-hydroxyvitamin D levels to nanomoles per liter, multiply by 2.496]) were higher for all-cause mortality (HR, 2.08; 95% confidence interval [CI], 1.60-2.70; and HR, 1.53; 95% CI, 1.17-2.01; respectively) and for cardiovascular mortality (HR, 2.22; 95% CI, 1.57-3.13; and HR, 1.82; 95% CI, 1.29-2.58; respectively) compared with patients in the highest 25-hydroxyvitamin D quartile (median, 28.4 ng/mL). Similar results were obtained for patients in the lowest 1,25-dihydroxyvitamin D quartile. These effects were independent of coronary artery disease, physical activity level, Charlson Comorbidity Index, variables of mineral metabolism, and New York Heart Association functional class. Low 25-hydroxyvitamin D levels were significantly correlated with variables of inflammation (C-reactive protein and interleukin 6 levels), oxidative burden (serum phospholipid and glutathione levels), and cell adhesion (vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 levels). CONCLUSIONS Low 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels are independently associated with all-cause and cardiovascular mortality. A causal relationship has yet to be proved by intervention trials using vitamin D.

Platelet-Activating Factor Acetylhydrolase Activity Indicates Angiographic Coronary Artery Disease Independently of Systemic Inflammation and Other Risk Factors The Ludwigshafen Risk and Cardiovascular Health Study

Background—Platelet-activating factor acetylhydrolase (PAF-AH), also denoted as lipoprotein-associated phospholipase A2, is a lipoprotein-bound enzyme that is possibly involved in inflammation and atherosclerosis. This study investigates the relationship of PAF-AH activity to angiographic coronary artery disease (CAD), the use of cardiovascular drugs, and other established risk factors. Methods and Results—PAF-AH activity, lipoproteins, sensitive C-reactive protein (sCRP), fibrinogen, serum amyloid A, and white blood cell count were determined in 2454 subjects with angiographically confirmed CAD and in 694 control subjects. PAF-AH activity was highly correlated with LDL cholesterol (r=0.517), apolipoprotein B (r=0.644), and non-HDL cholesterol (r=0.648) but not with sCRP or fibrinogen. PAF-AH activity was lower in women than in men and was affected by the intake of lipid-lowering drugs (−12%; P<0.001), aspirin (−6%; P<0.001), &bgr;-blockers (−6%; P<0.001), and digitalis (+7%; P<0.001). Unlike sCRP, fibrinogen, and serum amyloid A, PAF-AH activity was not elevated in unstable angina, non–ST-elevation myocardial infarction, or ST-elevation myocardial infarction. When nonusers of lipid-lowering drugs were examined, PAF-AH activity was associated with the severity of CAD and the number of coronary vessels with significant stenoses. In individuals not taking lipid-lowering drugs and after adjustment for use of aspirin, &bgr;-blocker, and digitalis, the odds ratio for CAD associated with increasing PAF-AH activity was 1.39 (95% CI 1.26 to 1.54, P<0.001), a finding that was robust against further adjustments. Conclusions—PAF-AH activity is not an indicator of the systemic inflammation that accompanies acute coronary syndromes. PAF-AH activity is affected by a number of cardiovascular drugs; however, after such medication use was accounted for, PAF-AH activity was associated with angiographic CAD, complementary to sCRP and independently of established risk factors such as LDL cholesterol.

The Friedewald Formula Underestimates LDL Cholesterol at low Concentrations

Abstract Due to recent advances in the treatment of hypercholesterolemia, low density lipoprotein (LDL) cholesterol concentrations below 2.6 mmol/l have become attainable. In general, LDL cholesterol is determined indirectly according to Friedewald. We examined the performance of the Friedewald formula at low concentrations of LDL cholesterol in comparison with a β-quantification method. We analyzed 176 samples from individuals treated by LDL apheresis with a mean LDL cholesterol concentration of 3.07 mmol/l and found that the Friedewald formula underestimated LDL cholesterol with a bias of −18.5%, −14.5%, −7.3%, and −3.8% at mean LDL cholesterol levels of 1.58, 2.4, 3.49, and 4.67 mmol/l, respectively. Thus, the lower the LDL cholesterol concentration was, the greater the negative bias. We conclude that the Friedewald formula may not be reliable at low LDL cholesterol concentrations produced by LDL apheresis. This finding may also be of relevance to the monitoring of patients being treated with lipid lowering drugs.

Cholesteryl Ester Transfer Protein and Mortality in Patients Undergoing Coronary Angiography The Ludwigshafen Risk and Cardiovascular Health Study

Background— The role of cholesteryl ester transfer protein (CETP) in the development of atherosclerosis is still open to debate. In the Investigation of Lipid Level Management to Understand its Impact in Atherosclerotic Events (ILLUMINATE) trial, inhibition of CETP in patients with high cardiovascular risk was associated with increased high-density lipoprotein levels but increased risk of cardiovascular morbidity and mortality. In this report, we present a prospective observational study of patients referred to coronary angiography in which CETP was examined in relation to morbidity and mortality. Methods and Results— CETP concentration was determined in 3256 participants of the Ludwigshafen Risk and Cardiovascular Health (LURIC) study who were referred to coronary angiography at baseline between 1997 and 2000. Median follow-up time was 7.75 years. Primary and secondary end points were cardiovascular and all-cause mortality, respectively. CETP levels were higher in women and lower in smokers, in diabetic patients, and in patients with unstable coronary artery disease, respectively. In addition, CETP levels were correlated negatively with high-sensitivity C-reactive protein and interleukin-6. After adjustment for age, sex, medication, coronary artery disease status, cardiovascular risk factors, and diabetes mellitus, the hazard ratio for death in the lowest CETP quartile was 1.33 (1.07 to 1.65; P=0.011) compared with patients in the highest CETP quartile. Corresponding hazard ratios for death in the second and third CETP quartiles were 1.17 (0.92 to 1.48; P=0.19) and 1.10 (0.86 to 1.39; P=0.46), respectively. Conclusions— We interpret our data to suggest that low endogenous CETP plasma levels per se are associated with increased cardiovascular and all-cause mortality, challenging the rationale of pharmacological CETP inhibition.

Apolipoprotein E isoforms and the development of low and high Braak stages of Alzheimer’s disease-related lesions

Abstract In recent research, apolipoprotein-E (apoE) polymorphism has been shown to influence the formation of neurofibrillary changes and the accumulation of β/A4-amyloid, the histopathological hallmarks of Alzheimer’s disease (AD). Clinical studies associate the apoE allele ɛ4 with earlier onset of the disease, although the clinical speed of progression remains unchanged. Time course estimates have also provided evidence which indicates that the clinical phase of AD constitutes only 10–20% of the total time span needed for the development of this slowly progressing degenerative brain disorder. Due to the lack of reliable clinical tests for the detection of pre-symptomatic stages of AD, we set out with an autopsy approach to monitor neuropathology of the long pre-clinical phase of AD. This study examined β/A4-peptide deposition and the formation of neurofibrillary changes staged according to the Braaks’ classification in groups of individuals matched for age and sex with different genotypes. In comparison with ɛ3 homozygotes, the presence of the ɛ4 allele is statistically associated with a higher stage of β/A4-peptide deposition and neurofibrillary change formation (χ2-test, P < 0.01 for β/A4-stage and P < 0.001 for neurofibrillary changes). The effect of the ɛ2 allele differs. Its presence is associated with a lower stage of neurofibrillary pathology in individuals below the age of 80 but with a higher stage thereafter compared to age- and sex-matched ɛ3 homozygotes. Accordingly, the statistical juxtaposition of individuals over 80 years with ɛ4 alleles and those with ɛ2 alleles showed no significant difference with respect to the stages. Our findings indicate that apoE-variants have different effects on the speed of histopathology formation, even in the pre-clinical stages of AD. This suggests that clinical onset, course and pathogenesis of AD are influenced by the apoE genotype.

Interleukin-6 Stimulates LDL Receptor Gene Expression via Activation of Sterol-Responsive and Sp1 Binding Elements

Inflammatory or malignant diseases are associated with elevated levels of cytokines and abnormal low density lipoprotein (LDL) cholesterol metabolism. In the acute-phase response to myocardial injury or other trauma or surgery, total and LDL cholesterol levels are markedly decreased. We investigated the effects of the proinflammatory cytokine interleukin (IL)-6 on LDL receptor (LDL-R) function and gene expression in HepG2 cells. IL-6 dose-dependently increased the binding, internalization, and degradation of (125)I-LDL. IL-6-stimulated HepG2 cells revealed increased steady-state levels of LDL-R mRNA. In HepG2 cells transiently transfected with reporter gene constructs harboring the sequence of the LDL-R promoter extending from nucleotide -1563 (or from nucleotide -234) through -58 relative to the translation start site, IL-6 dose-dependently increased promoter activity. In the presence of LDL, a similar relative stimulatory effect of IL-6 was observed. Studies using a reporter plasmid with a functionally disrupted sterol-responsive element (SRE)-1 revealed a reduced stimulatory response to IL-6. In gel-shift assays, nuclear extracts of IL-6-treated HepG2 cells showed an induced binding of SRE binding protein (SREBP)-1a and SRE binding protein(SREBP)-2 to the SRE-1 that was independent of the cellular sterol content and an induced binding of Sp1 and Sp3 to repeat 3 of the LDL-R promoter. Our data indicate that IL-6 induces stimulation of the LDL-R gene, resulting in enhanced gene transcription and LDL-R activity. This effect is sterol independent and involves, on the molecular level, activation of nuclear factors binding to SRE-1 and the Sp1 binding site in repeat 2 and repeat 3 of the LDL-R promoter, respectively.

Low-Density Lipoprotein Triglycerides Associated With Low-Grade Systemic Inflammation, Adhesion Molecules, and Angiographic Coronary Artery Disease The Ludwigshafen Risk and Cardiovascular Health Study

Background—Markers of systemic inflammation and LDL cholesterol (LDL-C) have been considered independent risk factors of coronary artery disease (CAD). We examined whether alterations of LDL metabolism not reflected by LDL-C were associated with low-grade inflammation, vascular injury, and CAD. Methods and Results—We studied 739 subjects with stable angiographic CAD and 570 matched control subjects in which CAD had been ruled out by angiography. The association of LDL triglycerides (LDL-TGs) (odds ratio [OR], 1.30; 95% CI, 1.19 to 1.43; P<0.001) with CAD was stronger than that of LDL-C (OR, 1.10; 95% CI, 1.00 to 1.21; P=0.047). The predictive value of LDL-TG for CAD was independent of LDL-C. “Sensitive” C-reactive protein (CRP), serum amyloid A, fibrinogen, interleukin 6, intercellular adhesion molecule-1 (ICAM-1), and vascular adhesion molecule-1 (VCAM-1) increased in parallel to LDL-TG. CRP, ICAM-1, and VCAM-1 were inversely related to LDL-C. To examine whether LDL-TGs were associated with the distribution of LDL subfractions, we studied 114 individuals with impaired fasting glucose, impaired glucose tolerance, or type 2 diabetes mellitus. In subjects with high LDL-TG, LDLs were depleted of cholesteryl esters (CEs), and VLDLs, IDLs, and dense LDLs were significantly elevated. Conclusions—Alterations of LDL metabolism characterized by high LDL-TG are related to CAD, systemic low-grade inflammation, and vascular damage. High LDL-TGs are indicative of CE-depleted LDL, elevated IDL, and dense LDL. LDL-TG may better reflect the atherogenic potential of LDL than LDL-C.

Atorvastatin and Low-Density Lipoprotein Cholesterol in Type 2 Diabetes Mellitus Patients on Hemodialysis

BACKGROUND AND OBJECTIVES Patients undergoing maintenance hemodialysis are at high cardiovascular risk. Lowering LDL-cholesterol with statins reduces the incidence rate of cardiovascular events in patients with chronic kidney disease. In contrast, two randomized, prospective, placebo-controlled trials have been completed in hemodialysis patients that showed no significant effects of statins on cardiovascular outcomes. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A post hoc analysis was conducted of the 4D (Die Deutsche Diabetes Dialyze) study to investigate whether LDL-cholesterol at baseline is predictive of cardiovascular events and whether the effect of atorvastatin on clinical outcomes depends on LDL-cholesterol at baseline. RESULTS High concentrations of LDL-cholesterol by tendency increased the risks of cardiac endpoints and all-cause mortality. Concordantly, atorvastatin significantly reduced the rates of adverse outcomes in the highest quartile of LDL-cholesterol (≥145 mg/dl, 3.76 mmol/L). The hazard ratios and 95% confidence intervals were 0.69 (0.48 to 1.00) for the composite primary endpoint, 0.58 (0.34 to 0.99) for cardiac death, 0.48 (0.25 to 0.94) for sudden cardiac death, 0.62 (0.33 to 1.17) for nonfatal myocardial infarction, 0.68 (0.47 to 0.98) for all cardiac events combined, and 0.72 (0.52 to 0.99) for death from all causes, respectively. No such decrease was seen in any of the other quartiles of LDL-cholesterol at baseline. CONCLUSIONS In patients with type 2 diabetes mellitus undergoing hemodialysis, atorvastatin significantly reduces the risk of fatal and nonfatal cardiac events and death from any cause if pretreatment LDL-cholesterol is >145 mg/dl (3.76 mmol/L).

Effects of vitamin D on blood pressure and cardiovascular risk factors: a randomized controlled trial.

Vitamin D deficiency is a risk factor for arterial hypertension, but randomized controlled trials showed mixed effects of vitamin D supplementation on blood pressure (BP). We aimed to evaluate whether vitamin D supplementation affects 24-hour systolic ambulatory BP monitoring values and cardiovascular risk factors. The Styrian Vitamin D Hypertension Trial is a single-center, double-blind, placebo-controlled study conducted from June 2011 to August 2014 at the endocrine outpatient clinic of the Medical University of Graz, Austria. We enrolled 200 study participants with arterial hypertension and 25-hydroxyvitamin D levels below 30 ng/mL. Study participants were randomized to receive either 2800 IU of vitamin D3 per day as oily drops (n=100) or placebo (n=100) for 8 weeks. Primary outcome measure was 24-hour systolic BP. Secondary outcome measures were 24-hour diastolic BP, N-terminal-pro-B-type natriuretic peptide, QTc interval, renin, aldosterone, 24-hour urinary albumin excretion, homeostasis model assessment-insulin resistance, triglycerides, high-density lipoprotein cholesterol, and pulse wave velocity. A total of 188 participants (mean [SD] age, 60.1 [11.3] years; 47% women; 25-hydroxyvitamin D, 21.2 [5.6] ng/mL) completed the trial. The mean treatment effect (95% confidence interval) for 24-hour systolic BP was −0.4 (−2.8 to 1.9) mm Hg (P=0.712). Triglycerides increased significantly (mean change [95% confidence interval], 17 [1–33] mg/dL; P=0.013), but no further significant effects were observed for secondary outcomes. Vitamin D supplementation in hypertensive patients with low 25-hydroxyvitamin D has no significant effect on BP and several cardiovascular risk factors, but it was associated with a significant increase in triglycerides. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT02136771.

Atorvastatin in patients with primary biliary cirrhosis and incomplete biochemical response to ursodeoxycholic acid

Statin therapy may target both hypercholesterolemia and cholestasis in primary biliary cirrhosis (PBC). However, little is known about the efficacy and safety of statins in PBC. The aim of this single‐center study was therefore to prospectively examine the effects of atorvastatin on serum markers of cholestasis, aminotransferases, and lipid and bile acid metabolism as well as inflammatory and immunological markers in patients with PBC. Fifteen patients with early‐stage PBC and an incomplete biochemical response to ursodeoxycholic acid (UDCA) therapy (defined as alkaline phosphatase 1.5‐fold above the upper limit of normal after 1 year) were treated with atorvastatin 10 mg/day, 20 mg/day, and 40 mg/day for 4 weeks, respectively. Serum levels of alkaline phosphatase increased during atorvastatin 20 mg and 40 mg (P < 0.05), whereas leucine aminopeptidase and γ‐glutamyltransferase remained unchanged. No statistical differences in overall serum ALT, AST, bilirubin, and IgM levels were observed. However, atorvastatin was discontinued in 1 out of 15 patients because of ALT 2‐fold above baseline, and 2 patients showed ALT elevations 3‐fold above the upper limit of normal at the end of the atorvastatin treatment period. Serum total cholesterol and low‐density lipoprotein cholesterol levels decreased by 35% and 49%, respectively (P < 0.001). Precursors of cholesterol biosynthesis (lanosterol, desmosterol, lathosterol) showed a similar pattern. No changes in serum bile acid levels and composition were observed during treatment. Conclusion: Atorvastatin does not improve cholestasis in PBC patients with an incomplete biochemical response to UDCA but effectively reduces serum cholesterol levels. (HEPATOLOGY 2007.)