G. Marotta

Effects of bezafibrate on insulin secretion and peripheral insulin sensitivity in hyperlipidemic patients with and without diabetes

Although it has been reported that bezafibrate influences carbohydrate metabolism, this possibility has never been properly evaluated in a controlled clinical trial. In this study we attempted to evaluate the effects of bezafibrate on plasma lipoproteins, glucose tolerance, insulin secretion and peripheral insulin sensitivity in a group of hypertriglyceridemic patients with and without diabetes. Sixteen hyperlipidemic patients (10 males and 6 females) participated in the study. Eight had type IIB and 8 type IV hyperlipoproteinemia; 6 of them also had non-insulin dependent diabetes mellitus. The study was performed according to a double blind, crossover design: after 1 month wash-out period in which patients were on diet alone, they underwent, in a random order, a period of placebo therapy and another period in which they received a single daily dose of a long-acting bezafibrate preparation (400 mg) administered in the evening. Each treatment lasted 2 months. Total plasma and VLDL triglyceride concentrations were consistently reduced by bezafibrate (-46%, P less than 0.001; and -50%, P less than 0.001). Total and VLDL-cholesterol were also reduced by bezafibrate. The effects of bezafibrate on lipoproteins were similar in diabetic and non-diabetic subjects. Bezafibrate treatment did not influence fasting blood glucose concentration, glucose tolerance, peripheral insulin sensitivity or insulin secretion. In conclusion, the results of this controlled trial clearly indicate that bezafibrate can be successfully employed to lower plasma lipid levels in patients with non-insulin dependent diabetes mellitus and hyperlipidemia.

Efficacy and safety of rosuvastatin in the management of dyslipidemia

Rosuvastatin is a synthetic statin that represents an advance in the pharmacologic and clinical properties of statins. Relative to other statins, rosuvastatin possesses a greater number of binding interactions with HMG-CoA reductase and has a high affinity for the active site of the enzyme. As with other statins, serious adverse effects with rosuvastatin therapy are uncommon and primarily involve effects on the liver and skeletal muscle. The risk increases with increasing dosages and coadministration with other drugs interacting with the same metabolic pathway. The degree of LDL reduction is important to achieve the treatment goals suggested by international guidelines. Among the most potent statins, rosuvastatin is capable of getting the majority of patients to their LDL cholesterol goals. In addition, rosuvastatin has been found effective in reducing small-dense LDL, C-reactive protein and in increasing HDL cholesterol levels. Controlled clinical trials using vascular end-points have been performed. In particular, a study demonstrated that rosuvastatin therapy could slow progression and/or cause regression of carotid intima-media thickness over 2 years in middle-aged individuals with a low Framingham risk score (FRS) and mild to moderate subclinical atherosclerosis. A primary prevention study (JUPITER) was stopped before the programmed end of the study, because of excess benefit for high-risk individuals receiving rosuvastatin treatment. It is suggested that pronounced LDL reduction, in association with significant HDL cholesterol increase, are the bases of a marked preventive action of rosuvastatin. The results from JUPITER support the use of rosuvastatin for primary cardiovascular prevention, in overweight men and women, with near to normal LDL cholesterol and high CRP. There is now evidence of benefit from rosuvastatin treatment for a wide segment of the general population at intermediate cardiovascular risk. In absolute numbers, this segment represents the main source of cardiovascular events: on the basis of JUPITER results, it is expected that treatment target and potential candidates to statin therapy will be revaluated and redefined.

Serum lipoproteins, apolipoproteins and very low density lipoprotein subfractions during 6-month fibrate treatment in primary hypertriglyceridaemia.

Abstract. Serum lipoproteins and apolipoproteins were studied in 14 hypertriglyceridaemic (HTG) patients during a 24‐week period of treatment with gemfibrozil, and after a 6‐week washout period. A marked decrease in very low density lipoprotein (VLDL) cholesterol and triglyceride was observed. There was an increase in high density lipoprotein (HDL) cholesterol, particularly the HDL3 component. A slight increase in low density lipoprotein (LDL) cholesterol was observed after 12 weeks, but this had almost disappeared after 24 weeks. The treatment resulted in an increase in serum apolipoprotein A‐II levels and a reduction in serum apo C‐III and apo E. VLDL subfractionation by density gradient centrifugation in four subfractions of decreasing size (A, B, C and D) showed a predominant reduction of the large subfractions A, B and C, while the decrease in VLDL‐D was less marked. Percentage changes from the baseline level of VLDL‐A and VLDL‐D cholesterol were found to be inversely correlated with percentage changes in HDL and LDL cholesterol, respectively. This might reflect a transfer of cholesterol from VLDL‐A to HDL, and from VLDL‐D to LDL. The above data suggest fibrate‐induced stimulation of lipoprotein lipase, and indicate that the enhanced transfer of cholesterol from VLDL to LDL, induced by fibrates in HTG patients, is less pronounced after a prolonged period of treatment.

Small dense low-density lipoprotein in familial combined hyperlipidemia: Independent of metabolic syndrome and related to history of cardiovascular events

INTRODUCTION It is unclear whether small dense low-density lipoprotein (sdLDL) are associated with familial combined hyperlipidemia (FCHL), independently of the metabolic syndrome (MS). It is also unclear whether sdLDL are related to history of cardiovascular (CVD) events in FCHL patients, independently of MS. PATIENTS AND METHODS Serum levels of sdLDL, expressed as percentage of total LDL cholesterol (LDL score), were determined in 137 probands with FCHL and in 133 normolipidemic, normotensive, normoglycemic healthy subjects. RESULTS In binary logistic regression age- and gender-adjusted LDL score values above the 90th and 95th percentiles of the values in the control group (10.23 and 13.11%, respectively) were found to be significant predictors of FCHL status, independently of MS diagnosis (p=0.007 and p<0.0001, respectively). Values of the LDL score above the 90th and the 95th percentile of the control group resulted to be significantly related to FCHL status, even after adjustment for the components of MS (p=0.006 and p=0.001, respectively). Among FCHL patients, values of the LDL score above 95th percentile of the values in the control group were found to be significantly related to personal and/or family history of CVD events, independently of age, gender, total cholesterol, apolipoprotein (apo) B, and MS status (p=0.016). The same significant relationship was found adjusting for all components of MS (p=0.034). CONCLUSIONS High concentrations of sdLDL are highly specific markers of FCHL, independently of concomitant MS. In FCHL patients high levels of sdLDL are related to history of CVD events, independently of MS, total cholesterol and apo B.

Identification and functional characterization of LDLR mutations in familial hypercholesterolemia patients from Southern Italy

OBJECTIVE Autosomal dominant hypercholesterolemias are due to defects in the LDL receptor (LDLR) gene, in the apolipoprotein B-100 gene or in the proprotein convertase subtilisin/kexin type 9 gene. The aim of this study was to identify and functionally characterize mutations in the LDLR gene that account for most cases of familial hypercholesterolemia (FH). METHODS We enrolled 56 unrelated patients from Southern Italy with a clinical diagnosis of FH. The mutation screening was performed by direct sequencing of the promoter and the 18 exons of the LDLR gene and by multiplex ligation-dependent probe amplification (MLPA) analysis to search for large rearrangements. RESULTS AND CONCLUSION We found 5 new mutations, the causative role of which was demonstrated by functional characterization performed by quantification of fluorescent LDL uptake in EBV-transformed B lymphocytes. These results enlarge the spectrum of FH-causative LDLR mutations. Lastly, screening for large rearrangements is highly recommended for the genetic diagnosis of FH.

An improved method on stimulated T-lymphocytes to functionally characterize novel and known LDLR mutations

The main causes of familial hypercholesterolemia (FH) are mutations in LDL receptor (LDLR) gene. Functional studies are necessary to demonstrate the LDLR function impairment caused by mutations and would be useful as a diagnostic tool if they allow discrimination between FH patients and controls. In order to identify the best method to detect LDLR activity, we compared continuous Epstein-Barr virus (EBV)-transformed B-lymphocytes and mitogen stimulated T-lymphocytes. In addition, we characterized both novel and known mutations in the LDLR gene. T-lymphocytes and EBV-transformed B-lymphocytes were obtained from peripheral blood of 24 FH patients and 24 control subjects. Functional assays were performed by incubation with fluorescent LDL followed by flow cytometry analysis. Residual LDLR activity was calculated normalizing fluorescence for the mean fluorescence of controls. With stimulated T-lymphocytes we obtained a better discrimination capacity between controls and FH patients compared with EBV-transformed B-lymphocytes as demonstrated by receiver operating characteristic (ROC) curve analysis (the areas under the curve are 1.000 and 0.984 respectively; P < 0.0001 both). The characterization of LDLR activity through T-lymphocytes is more simple and faster than the use of EBV-transformed B-lymphocytes and allows a complete discrimination between controls and FH patients. Therefore the evaluation of residual LDLR activity could be helpful not only for mutation characterization but also for diagnostic purposes.

Plasma creatinine levels, estimated glomerular filtration rate and carotid intima media thickness in middle-aged women: a population based cohort study.

BACKGROUND AND AIM The relationships between high Creatinine (Cr) levels or low estimated Glomerular Filtration Rate (eGFR) and common carotid Intima Media thickness (IMT) have been evaluated in a population-based cohort study in women, aged 30-69 (Progetto ATENA). METHODS AND RESULTS Serum Cr and eGFR were measured in 310 women, as a part of 5.062. In this group carotid ultrasound examination (B-Mode imaging) was performed and mean max IMT was calculated. Women were classified by Cr levels >1 mg/dL or eGFR < 56 ml/min. Women with Cr > 1 mg/dL (90th percentile of creatinine distribution) or eGFR less than 56 ml/min (5th percentile of eGFR distribution) had relatively more carotid plaques as compared to the rest of the cohort. Multivariate logistic analysis, after adjustment for age, demonstrated a significant association between Cr (>1 mg/dL) and IMT (≥1.2 mm): OR 4.12 (C.I 1.22-13.86), p = 0.022; or eGFR (<56 ml/min) and IMT (≥1.2 mm): OR 4.31 (C.I 1.27-14.66), p = 0.019. CONCLUSIONS These findings on an independent relationship between Cr and common carotid plaques in this population of middle aged women, independently of age, suggest the value of screening for early carotid disease in asymptomatic middle aged-women with mild renal insufficiency, in order to predict those at relatively higher risk for future cardiovascular events.

Tumor necrosis factor-α is a marker of familial combined hyperlipidemia, independently of metabolic syndrome

It is unclear whether an association between familial combined hyperlipidemia (FCHL) and inflammatory markers exists, independently of age, sex, body weight, insulin resistance, and metabolic syndrome. Serum concentrations of soluble vascular cell adhesion molecule-1 (sVCAM-1), monocyte chemoattractant protein 1, interleukin 6, tumor necrosis factor-alpha (TNF-alpha), and high-sensitive C-reactive protein were determined in 135 probands with FCHL and in 146 normolipidemic, normotensive, normoglycemic healthy subjects. Insulin resistance was evaluated using homeostasis model assessment (HOMA). All inflammatory parameters, except interleukin 6, were significantly higher in FCHL according to medians or mean comparisons. After adjustment for age, sex, body mass index, and HOMA, only TNF-alpha remained an independent predictor of FCHL status by binary logistic regression (odds ratio [OR], 1.19; 95% confidence interval [CI], 1.07-1.31; P = .001). In particular, elevated levels of TNF-alpha (above the 90th and 95th percentiles of the value observed in the control group, 9.6 and 9.8 pg/mL, respectively) were independent predictors of FCHL status: for TNF-alpha above the 90th percentile, OR was 7.91 (95% CI, 3.27-19.13; P < .001), and for TNF-alpha above 95th percentile, OR was 13.08 (95% CI, 4.60-37.15; P < .0001). The independent role of TNF-alpha as predictor of FCHL status was confirmed after adjustment for components of the metabolic syndrome (P = .007 and P = .003, for TNF-alpha values above 90th and 95th percentiles, respectively). In conclusion, among the inflammatory markers most commonly measured, only TNF-alpha was associated with FCHL independently of age, sex, body mass index, and HOMA. The association of TNF-alpha with FCHL was also independent of the metabolic syndrome.

The novel variant p.Ser465Leu in the PCSK9 gene does not account for the decreased LDLR activity in members of a FH family.

*Corresponding author: Giuliana Fortunato, Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, via S. Pansini 5, 80131 Napoli; and CEINGE Biotecnologie Avanzate s.c. a r.l., via Gaetano Salvatore 486, 80145 Napoli, Italy, Phone: +39 0817464200, Fax: +39 0817462404, E-mail: fortunat@unina.it Anna Ruotolo, Maria Nicoletta D’Agostino, Rosa Di Noto and Luigi Del Vecchio: Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Naples, Italy; and CEINGE Biotecnologie Avanzate s.c. a r.l., Naples, Italy Maria Donata Di Taranto: IRCCS Fondazione SDN, Naples, Italy Gennaro Marotta, Marco Gentile, Maria Nunziata, Marta Sodano and Paolo Rubba: Dipartimento di Medicina Clinica e Chirurgia, Università degli Studi di Napoli Federico II, Naples, Italy

Investigation of Single Nucleotide Polymorphisms Associated to Familial Combined Hyperlipidemia with Random Forests

Single nucleotide polymorphisms (SNPs) are the foremost part of many genome association studies. Selecting a subset of SNPs that is sufficiently informative but still small enough to reduce the genotyping overhead is an important step towards disease-gene association. In this work, a Random Forest (RF) approach to informative SNPs selection in Familial Combined Hyperlipidemia (FCH) is proposed. FCH is the most common form of familial hyperlipidemia. Affected patients have elevated levels of plasma triglycerides and/or total cholesterol and show increased risk of premature coronary heart disease. In order to identify susceptibility markers for FCH we perform the analysis of 21 SNPs in ten genes associated with high cardiovascular risk. RF appears to be a useful technique in identifying gene polymorphisms involved in FCH: the identified SNPs confirmed some variants in a couple of genes as genetic markers of FCH as proved in various studies in scientific literature and lead us to report for the first time a further gene association with FCH. This result could be promising and encourages to further investigate on the role of the identified gene in the development of FCH phenotype.