Lipoprotein-associated phospholipase A2 activity is increased in patients with definite familial hypercholesterolemia compared with other forms of hypercholesterolemia.

BACKGROUND AND AIM: Lipoprotein-associated phospholipase A2 (Lp-PLA2) plays a key role in atherosclerosis development. It is considered a marker of increased risk of cardiovascular disease (CVD) and plaque vulnerability. Familial hypercholesterolemia (FH) is a genetic disorder characterized by elevated plasma levels of low-density lipoprotein cholesterol and a higher prevalence of early CVD. Our aim was to evaluate the differences in Lp-PLA2 activity in a population of hypercholesterolemic patients with and without definite FH. METHODS AND RESULTS: Hypercholesterolemic patients were consecutively recruited. Definite FH was defined according to Dutch Lipid Clinic Network criteria ≥8. All patients underwent routine clinical examination and biological assessments and Lp-PLA2 activity was measured in blood samples. Among 469 patients, 118 had a definite diagnosis of FH. Lp-PLA2 activity was significantly higher in definite FH patients compared to non-definite FH patients (206.5 ± 54.5 vs. 180.8 ± 48.4 nmol/min/mL, p < 0.0001). Lp-PLA2 positively correlated with total cholesterol, LDL-C and apolipoprotein B and negatively with HDL-C and apolipoprotein A-1. In multivariate analysis, definite FH diagnosis, LDL-C, HDL-C and statin treatment remained correlates of Lp-PLA2 independently of systolic blood pressure. CONCLUSIONS: Lp-PLA2 activity was higher in definite FH than in non-definite FH patients independently of LDL-C levels and statin treatment. These results highlight the particular phenotype of FH subjects among hypercholesterolemic patients. As increased Lp-PLA2 activity suggests, FH patients exhibit higher arterial inflammation that may contribute to their high cardiovascular risk. Our results reinforce the potential beneficial role of statins pleiotropic effects and the need for proper identification and treatment of FH patients.

Baseline metabolic disturbances and the twenty-five years risk of incident cancer in a Mediterranean population.

BACKGROUND AND AIMS: Obesity is predictive of metabolic syndrome (metS), type 2 diabetes, cardiovascular (CV) disease and cancer. The aim of the study is to assess the risk of incident cancer connected to obesity and metS in a Mediterranean population characterized by a high prevalence of obesity. METHODS AND RESULTS: As many as 1133 subjects were enrolled in two phases and followed for 25 years (859 subjects) or 11 years (274 subjects) and incident cancer was registered in the follow-up period. Anthropometric measures and biochemical parameters were filed at baseline and evaluated as predictors of incident cancer by measuring hazards ratios (HR) using multivariate Cox parametric hazards models. Best predictive threshold for metabolic parameters and metS criteria were recalculated by ROC analysis. Fasting Blood Glucose >5.19 mmol/L [HR = 1.58 (1.0-2.4)] and the TG/HDL ratio (log10) (Males > 0.225, Females > 0.272) [HR = 2.44 (1.3-4.4)] resulted independent predictors of survival free of cancer with a clear additive effect together with age classes [45-65 years, HR = 2.47 (1.3-4.4), 65-75 years HR = 3.80 (2.0-7.1)] and male gender [HR = 2.07 (2.3-3.1)]. CONCLUSIONS: Metabolic disturbances are predictive of cancer in a 25 years follow-up of a Mediterranean population following a traditional Mediterranean diet. The high prevalence of obesity and metS and the observed underlying condition of insulin resistance expose this population to an increased risk of cardiovascular disease and cancer despite the healthy nutritional habits.

A novel component of the metabolic syndrome: the oxidative stress.

The metabolic syndrome (MS) represents a cluster of cardiovascular (CV) risk factors associated to CV disease and type 2 diabetes. It is still under debate whether MS is a mere aggregation of risk factors or it represents a clinical entity with visceral obesity as underlying pathophysiological trigger. The publication of several diagnostic criteria of MS by scientific associations or experts panels reflects this uncertainty in understanding the real nature of MS. Besides the metabolic disturbances of MS, as visceral obesity, hypertriglyceridemia, low HDL cholesterol, hypertension and hyperglycemia, novel mechanisms of arterial damage have been identified. This paper reviews the evidence showing that MS and MS factors are characterized by increased oxidative stress, a relevant factor contributing to the development of metabolic and cardiovascular complications. In the next future, the measure of plasma oxidative stress may contribute to identify a subset of MS patients at increased CV risk, candidates to more intensive therapies.

Down regulation of CD11b and CD18 expression in children with hypercholesterolemia: a preliminary report.

BACKGROUND AND AIM: Cell adhesion molecules play an important role in the development of atherosclerosis mediating the attachment of monocytes to the endothelium. The aim of our study was to assess the cell surface expression of CD11b/CD18 integrin on the phagocytes of children affected by hypercholesterolemia. METHODS AND RESULTS: Twenty-six children with hypercholesterolemia (15 males, mean age 8.3, range 2-18) with a family history of early cardiovascular disease, as well as 26 children with normocholesterolemia matched for gender and age (15 males, mean age 8.3) were studied. Cell surface expression of CD11b/CD18 on peripheral blood mononuclear cells (PBMC) were analyzed by flow cytometry. The geometric mean percentages of CD11b and CD18 expression were significantly lower in the hypercholesterolemic group [52 (95% confidence intervals, 40-68) and 88 (84-93)] than in the control group [87 (83-91), P<0.0001 and 93 (89-96), P<0.05], respectively. After correction for age, gender, and pubertal status, CD11b cell surface expression on PBMC was inversely and independently correlated with total cholesterol concentrations (r=-0.395; P<0.01) and LDL (r=-0.307; P<0.05), as well as with triglycerides (r=-0.406; P<0.01). CONCLUSIONS: In children with hypercholesterolemia, cell surface expression of CD11b and CD18 on PBMC was significantly decreased. Follow-up studies are necessary to determine the clinical implications of these findings in the context of the natural course and progression of atherosclerosis in high risk children.

Hypertension and diabetes mellitus are associated with cardiovascular events in the elderly without cardiovascular disease. Results of a 15-year follow-up in a Mediterranean population.

BACKGROUND AND AIMS: Epidemiological prospective data on cardiovascular (CV) events in elderly subjects from Mediterranean populations are lacking. We aimed to investigate 15-year incidence of CV events and to evaluate the association with CV risk factors in an elderly Mediterranean population. METHODS AND RESULTS: The population of a small Sicilian village were enrolled, visited and a blood sample was drawn at baseline. CV events were recorded in the 15 years of follow-up. From 1351 subjects (75% of the resident population); 315 were in the age range 65-85 years; 266 subjects free from CV disease were analysed. Seventy-seven CV events were recorded in 73 out of 266 subjects, with a 19.7% rate (in 10 years). Hypertension (HTN) (hazards ratio=2.1) and diabetes mellitus (DM) (hazards ratio=1.8) were independently associated with CV events. Subjects with both DM and HTN showed a lower survival free of CV events compared to those with DM or HTN. CONCLUSIONS: In a 15-year follow-up of an elderly Mediterranean population free from CV disease, diabetes mellitus and hypertension were related to CV events. The control of risk factors in the elderly needs to be reinforced to achieve better results in terms of CV prevention.

Obesity and the metabolic syndrome in a student cohort from Southern Italy.

BACKGROUND AND AIM: Cardiovascular (CV) risk factors present in childhood predict future CV events. Few data regarding the metabolic syndrome (MS) prevalence are available in adolescents from Mediterranean areas where obesity is becoming a social emergency. This study presents data of MS prevalence in a student cohort from southern Italy. METHODS AND RESULTS: 1629 students between 7 and 14 years of age underwent anthropometric measurements and a blood sample was obtained to assess biochemical parameters. MS risk factors were calculated based on age and gender adjusted percentiles of parameter distributions. MS prevalence rate was 0.022 using paediatric, age-adjusted criteria; the rate increased to 0.029 using a 90th percentile criteria for fasting blood glucose instead of >100mg/dL. Using the criteria issued by the International Diabetes Federation the MS prevalence rate dropped to 0.005. The exploratory factor analysis identified four factors: age/fat related, lipids, blood pressure and blood glucose. Family history of type 2 diabetes mellitus was associated with triglyceride [OR=1.55 (1.0-2.3)] and BMI [OR=1.71 (1.2-2.4)] but not to blood glucose by logistic regression analysis. CONCLUSIONS: In a student cohort from Southern Italy, obesity is associated with the features of MS.

SGK-1 protects kidney cells against apoptosis induced by ceramide and TNF-α.

Ceramide regulates several different cellular responses including mechanisms leading to apoptosis. Serum- and glucocorticoid-inducible protein kinase (SGK)-1 is a serine threonine kinase, which activates survival pathways in response to stress stimuli. Recently, we demonstrated an anti-apoptotic role of SGK-1 in human umbilical endothelial cells treated with high glucose. In the present study, since ceramide induces apoptosis by multiple mechanisms in diabetes and its complication such as nephropathy, we aimed to investigate whether SGK-1 may protect even against apoptosis induced by ceramide in kidney cells. Human embryonic kidney (HEK)-293 cells stable transfected with SGK-1 wild type (SGK-1wt) and its dominant negative gene (SGK-1dn) have been used in this study. Apoptotic stimuli were induced by C2-ceramide and TNF-α to increase endogenous synthesis of ceramide. Upon activation with these stimuli, SGK-1wt transfected cells have a statistically significant reduction of apoptosis compared with SGK-1dn cells (P<0.001). This protection was dependent on activation of caspase-3 and Poly-ADP-ribose-polymerase-1 (PARP-1) cleavage. SGK-1 and AKT-1 two highly homologous kinases differently reacted to ceramide treatment, since SGK-1 increases in response to apoptotic stimulus while AKT-1 decreases. This enhancement of SGK-1 was dependent on p38-mitogen-activated-protein kinases (p38MAPK), cyclic-adenosine-monophosphate/protein kinase A (cAMP/PKA) and phosphoinositide-3-kinase (PI3K) pathways. Especially, by using selective LY294002 inhibitor, we demonstrated that the most involved pathway in the SGK-1 mediated process of protection was PI3K. Treatment with inhibitor of SGK-1 (GSK650394) significantly enhanced TNF-α-dependent apoptosis in HEK-293 cells overexpressing SGK-1wt. Caspase-3, -8 and -9 selective inhibitors confirmed that SGK-1 reduced the activation of caspase-dependent apoptosis, probably by both intrinsic and extrinsic pathways. In conclusion, we demonstrated that in kidney cells, overexpression of SGK-1 is protective against ceramide-induced apoptosis and the role of SGK-1 can be potentially explored as a therapeutic target in conditions like diabetes, where ceramide levels are increased.

Leukocyte count, diabetes mellitus and age are strong predictors of stroke in a rural population in southern Italy: an 8-year follow-up.

Stroke incidence rates in the Mediterranean area are higher compared to northern European countries. In this study, we present the 8-year prospective data from a small rural Sicilian town. This population, consisting of 1351 subjects (622 males and 729 females), is homogeneous for ethnic background with traditional healthy dietary habits and shows low cholesterol mean levels. We found that the risk of stroke was significantly associated with the record of at least one previous neurological symptom (PNS), such as lack of strength, loss of vision or speech or possible drop attacks, and high hematocrit in males, and to high body mass index (BMI) and waist-hip ratio (WHR), diabetes, hypertension, high leukocyte count in females. We also documented age-related differences: stroke was associated in younger subjects (age<65 years) with diabetes, high BMI, high uric acid levels and in older patients (age>/=65 years) with high WHR, hypertension, diabetes, PNS, leukocyte count and hematocrit above the 95th percentile. Multivariate analysis demonstrated an independent association between stroke and age, diabetes, leukocyte count, hypertension and PNS. In conclusion, in this rural Sicilian population, the incidence rate of stroke is 1.72 cases per 1000/year in the subjects between 40 and 75 years of age. The risk factors associated with stroke are different in younger and older subjects. Leukocyte count, as an expression of an undergoing inflammatory process, may have a relevant role at least in the elderly.

Autosomal recessive hypercholesterolemia in a Sicilian kindred harboring the 432insA mutation of the ARH gene.

We describe a Sicilian family presenting a recessive form of hypercholesterolemia harboring a mutation of the autosomal recessive hypercholesterolemia (ARH) gene. In two of the three sibs, a 26-year-old male and a 22-year-old female, a severe hypercholesterolemia was diagnosed with very high levels of plasma cholesterol (15.9 and 12.2 mmol/l, respectively); tendon xanthomatas and xanthelasms were present and in the male proband was documented a diffuse coronary atherosclerotic disease with a rapid and fatal progression. Both the parents had normal or slightly increased levels of plasma cholesterol. All causes of secondary hypercholesterolemia were ruled out as well as an involvement of the LDL receptor or apoB genes. Beta-Sitosterol plasma levels were in the normal range. Cultured fibroblasts from skin biopsy from parents and the two probands displayed a normal ability to bind and degrade 125I-LDL. Direct sequencing of ARH gene demonstrated the presence of a 432insA mutation in homozygosis in the two probands; parents were heterozygotes for the same mutation. This mutation is the first report of a mutation of the ARH gene responsible for recessive forms of hypercholesterolemia in Sicily.

Factor VII activity is an independent predictor of cardiovascular mortality in elderly women of a Sicilian population: results of an 11-year follow-up.

The aim of the Epidemiological project "Ventimiglia di Sicilia" is to identify the cardiovascular risk factors in a Sicilian population with a low risk profile and healthy nutritional habits. The risk of cardiovascular mortality in older subjects (over 60 years of age) is presented for an 11 year follow-up. Females showed higher prevalence of diabetes mellitus, hypertension, obesity and higher levels of total, LDL and HDL cholesterol, factor VII activity and fibrinogen compared to males. Cardiovascular mortality was related to hypertension and obesity in males, to high factor VII activity, obesity and diabetes mellitus in females. In a Logistic Regression model the same variables were independently correlated to cardiovascular mortality with the exception of obesity. In conclusion, these findings suggest that in a population with a low risk profile, other factors, such as factor VII activity, may emerge as predictors of cardiovascular mortality.

A new apolipoprotein B truncation (apo B-43.7) in familial hypobetalipoproteinemia: genetic and metabolic studies.

We describe a new truncation of apolipoprotein (apo) B in a white kindred with familial hypobetalipoproteinemia (FHBL). Apo B-43.7, found in a daughter and her father, was due to a C --> T change in base position 6162 of the apo B gene converting the arginine (residue 1986) codon CGA to a stop codon TGA. Both subjects were heterozygotes, and both apo B-43.7- and apo B-100-containing particles were present in plasma. On density gradient ultracentrifugation (DGUC), approximately 30% to 40% of apo B-43.7 floated with very-low-density lipoprotein (VLDL)/intermediate-density lipoprotein (IDL)-density particles and 60% to 70% floated with high-density lipoprotein (HDL)-density particles. To assess the metabolism of apo B, 13C-leucine was infused and its rates of appearance in and disappearance from apo B-43.7- and apo B-100-containing particles were quantified by multicompartmental kinetic analysis. Apo B-100 entered plasma via VLDL with a production rate of 30 mg x kg-1 x d-1. Fractional catabolic rates (FCRs) for apo B-100 VLDL, IDL, and low-density lipoprotein (LDL) were 20.0, 16.0, and 0.46 pools x d-1, respectively. The production rate of apo B-43.7 was 9.6 mg x kg-1 x d-1, and FCRs for apo B-43.7 VLDL- and HDL-like particles were 12.0 and 1.8 pools x d-1, respectively. Approximately 30% of apo B-43.7 in HDL-density particles was derived from VLDL apo B-43.7, and about 70% appeared to enter the plasma as HDLs. The relatively low production rate of apo B-43.7 is compatible with previous reports that apo B truncations are produced at lower rates than their apo B-100 counterparts.

The C(-260)>T gene polymorphism in the promoter of the CD14 monocyte receptor gene is not associated with acute myocardial infarction.

CD surface molecules mediates cell activation and signaling. In particular, CD14 on blood monocytes mediate monocyte/macrophage activation by lipopolysaccharide. Lipopolysaccharide and its receptor, CD14, have been implicated in atherogenesis. It has been recently shown that a C(-260)T polymorphism in the promoter of the CD14 receptor may be a risk factor for coronary artery disease. Recently this association has been questioned because no increased risk was found with the T allele, even in the homozygous state. In the present study we investigated a possible association between the C(-260)T polymorphism in the CD14 promoter and acute myocardial infarction. Two hundred and thrteen patients with and acute myocardial infarction 213 healthy controls were included in the study. Genotype frequencies of the C(-260)T polymorphism in the CD14 promoter were determined by polimerase chain reaction and the amplified product was cleaved with HaeIII. The frequency of the T allele was not significantly different in patients compared with controls. In this study we were not able to detect differences of frequency of the allele T (-260) in the promoter of the CD14 receptor gene in survivors of myocardial infarction and controls.

Italian familial defective apolipoprotein B patients share a unique haplotype with other Caucasian patients.

Familial defective apolipoprotein (apo) B-100 together with familial hypercholesterolemia are the two common genetic conditions that cause hypercholesterolemia. Familial defective apolipoprotein B-100 is due to mutations around codon 3500 of the apo B gene. The most-characterized mutation is a G>A transition at nucleotide 10,708 that results in the substitution of arginine by glutamine at codon 3500 (Apo B Arg3500Gln). Two other mutations are caused by a C>T transition, one at nucleotide 10,800 (Apo B Arg3531Cys) and the other at nucleotide 10,707 (apo B Arg3500Trp). In the present study we describe three new Italian cases of familial defective apolipoprotein B-100 (Apo B Arg3500Gln), one from the Liguria region and two from Sicily, and the haplotype of the apo B gene co-segregating with the mutation. By screening two groups of probands, clinically diagnosed as having Familial Hypercholesterolemia (700 from mainland Italy and 305 from Sicily), the prevalence of familial defective apolipoprotein B-100 due to Arg3500Gln was found to be very low (0.28% and 0.65%, respectively). The Arg3531Cys mutation was not detected in any proband. In the three new families with Arg3500Gln mutation in the present study and in one previously described in Italy, the mutation was associated with a unique apo B haplotype, which is consistent with data previously reported for Caucasian patients [XbaI-, MspI+, EcoRI-, presence of the 5' signal peptide insertion (Ins) allele, and the 49-repeat allele of the 3'-VNTR].

Apo-lipoprotein profile in subjects with extracranial carotid atherosclerosis.

Relationships between plasma lipoproteins and cerebrovascular atherosclerosis are not completely clear. In a group of asymptomatic nondiabetic normolipidemic subjects, plasma lipid and apolipoprotein profiles have been related to extracranial carotid atherosclerotic lesions, as assessed by B-mode ultrasonography and independent relations between lipid and clinical parameters and carotid atherosclerosis have been evaluated. We have found that subjects with atherosclerotic lesions (both intimal thickening or plaque) had TG levels and CHO/HDL-C and LDL-C/HDL-C ratios significantly higher and HDL-C and apo A-I levels significantly lower in comparison with subjects with normal arteries. When patients were divided according to the lesions of carotid arteries subjects with atherosclerotic plaque presented HDL-C and apo A-I levels significantly reduced and TG and apo B levels and CHO/HDL-C and LDL-C/HDL-C ratios significantly increased in comparison with subjects with normal arteries, and HDL-C levels reduced and CHO/HDL-C and LDL-C/HDL-C ratios increased in comparison with subjects with intimal thickening. Patients with intimal thickening and normal subjects differed for HDL-C and TG levels and CHO/HDL-C and LDL-C/HDL-C ratios. At multivariate analysis HDL-C levels (negatively), age, hypertension and cigarette smoking (positively) resulted independently associated with cerebrovascular atherosclerosis. Our data seem to show that, although several lipid and apoprotein abnormalities are able to initiate the atherosclerotic process in extracranial carotid district, probably the presence of low HDL-cholesterol levels is an important condition to determine the further worsening of the lesions.

Lipoprotein(A) levels and apoprotein(a) phenotypes in a Sicilian population.

The aim of this study was to evaluate the influence of lipoprotein(a) levels and apoprotein(a) isoform size in determining the low cardiovascular risk of a rural, inland Sicilian population. Plasma levels of total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, lipoprotein(a) and apoprotein B and AI were measured in a sample of 278 subjects (141 males, 137 females) representative of a population of 1351 subjects (622 males, 729 females). The apoprotein(a) isoforms were also identified. Results indicated that the levels of the common lipo-apoliproprotein parameters were lower than those of other populations, while lipoprotein(a) plasmatic levels and apoprotein(a) isoform distribution were similar to those of other Caucasian populations. The distribution of lipoprotein(a) levels was skewed to the right, with a higher prevalence of low levels, the apoprotein(a) isoforms most strongly represented in our sample were of intermediate size (25-27 kringles IV). Univariate analysis showed that lipoprotein(a) levels were correlated to apoprotein(a) isoform size (R = -0.48, p < 0.001) and to the age of the subjects (R = +0.13, p < 0.01). In a multiple regression analysis, lipoprotein(a) levels were correlated to the apoprotein(a) isoform size of the homozygous isoforms or smaller heterozygous isoforms, while larger heterozygous forms were not correlated. In conclusion, our study showed that in our population, lipoprotein(a) levels and apoprotein(a) isoforms are similar to those of other Caucasian populations. Other factors, such as the physical activity of a rural population or the Mediterranean diet, must be considered in order to explain the lower cardiovascular risk of this population.

[Plasma lipids and apoproteins. The effect of cigarette smoking]. / Lipidi ed apoproteine plasmatiche. Influenza del fumo di sigaretta.

Cigarette smoking produces lipo-apoprotein modifications, which makes it more atherogenic. In this study we have evaluated lipids and apoproteins in 178 normolipidemic, healthy subjects, in relation to their smoking habits. In smokers we have found lower levels of HDL-cholesterol and apo A-I and higher levels of triglyceride and apo B. Number of cigarette smoked in a day directly correlated with triglycerides and apo B (r = 0.321 and 0.313 respectively) and inversely with HDL-cholesterol (r = -0.274). These alterations seem to be due to an inhibition that smoking could cause on lipolytic processes. Further studies need to establish influences that smoking-related alterations have in the atherosclerotic lesions of smokers.

A case of adult onset type II citrullinemia with portal-systemic shunt.

A 48-year-old woman who had conscious disturbance and abnormal behaviors had been misdiagnosed as having hepatic encephalopathy due to hyperammonemia and portal-systemic shunt, and retrograde transvenous obliteration of the shunt did not improve her symptoms. Thereafter, analyses of plasma amino acids and citrin gene revealed a diagnosis of adult onset type II citrullinemia (CTLN2). She underwent auxiliary partial orthotopic liver transplantation (APOLT) using a left lobe graft from her brother, and her symptoms as well as hyperammonemia improved. Our case demonstrates the importance of CTLN2 as a differential diagnosis in patients with hyperammonemia and consciousness disturbance, even if they present with a portal-systemic shunt.