Hyperlipidemias: Carmena R

Carmena R, Betteridge DJ. · Endocrine Service, Hospital Clínico Universitario, University of Valencia, Avda Blasco Ibañez 15, 46010 Valencia, Spain. · Semin Vasc Med. · Pubmed #15861314 No free full text.

Abstract: Lipid abnormalities play an important part in raising the cardiovascular risk in diabetic subjects. The main components of diabetic dyslipidemia are increased plasma triglycerides, low concentration of high-density lipoprotein cholesterol, preponderance of small, dense low-density lipoprotein, and excessive postprandial lipemia. Small, dense low-density lipoprotein, the elevation in remnant triglyceride-rich lipoprotein particles, and the low high-density lipoprotein are the most powerful atherogenic components. The coexistence of these three factors strongly aggravates the lipid accumulation in the arterial wall and the formation of atherosclerotic plaques. The position of diabetes in cardiovascular risk assessment has been recently reviewed in the Harmonized Clinical Guidelines on Prevention of Atherosclerotic Vascular Disease. In general, patients with diabetes carry a high risk for cardiovascular disease, but the absolute risk varies depending on the type of diabetes, age, and population baseline risk. The Adult Treatment Program III (ATP III) and the American Heart Association have designated diabetes as a high-risk condition and recommended intensive risk-factor management. Concerning therapeutic targets, both ATP III and the American Diabetes Association (ADA) guidelines have identified low-density lipoprotein cholesterol as the first priority of lipid lowering, and the optimal level was set at less than 2.6 mmol/L (100 mg/dL). There is strong evidence, coming from landmark secondary prevention studies, that LDL lowering in people with diabetes is associated with significant clinical benefits. The benefits of statin therapy in type 2 diabetics can no longer be questioned. Ongoing clinical trials will help clarify the question of whether increasing high-density lipoprotein cholesterol with fibrates in the presence of low low-density lipoprotein levels (lower than 3.4 mmol/L, or 130 mg/dL) will be more beneficial than statin therapy alone. The new paradigms in risk-reduction therapies for type 2 diabetic subjects are focused on cardiovascular disease prevention, rather than only on glucose or lipid control. Therapeutic lifestyle changes are considered primary therapies for hyperglycemia and coexisting metabolic syndrome, which can be diagnosed in more than half of type 2 diabetes subjects. New perspectives of lipid management in type 2 diabetes should take into account that insulin resistance, increased lipolysis, and overproduction of large, buoyant, very low density lipoprotein particles are at the base of diabetic dyslipidemia. Accordingly, drugs acting in the regulatory steps of very low density lipoprotein assembly should be developed. Activation of peroxisome proliferator activated receptor alpha (PPARalpha), as occurs with fibrates, lowers free fatty acids (FFAs) and triglyceride levels. PPARgamma agonism, as demonstrated by the thiazolidinediones, increases triglyceride lipolysis, FFA transport, and conversion of FFAs to triglycerides. As separate activation of PPARalpha and PPARgamma improves lipid metabolism, the development of new drugs integrating PPARalpha and PPARgamma activity (PPAR-alpha/gamma agonists) is a promising line that may further improve insulin resistance, FFA metabolism, and consequently, atherogenic diabetic dyslipidemia.

Carmena R, Ascaso JF, Real JT. · Department of Medicine, Endocrinology Service, Hospítal Cliníco Universitario, University of Valencia, Valencia, Spain. · Nutr Metab Cardiovasc Dis. · Pubmed #11887432 No free full text.

Abstract: Obesity is frequently associated with high plasma triglyceride and reduced plasma high-density lipoprotein (HDL)-cholesterol (HDL-C) levels, and an increased concentration of apoB-carrying lipoproteins. The effects of obesity on lipid metabolism are mainly mediated by insulin resistance and, as central (visceral) obesity significantly increases insulin resistance, it aggravates these lipid changes. We have reviewed the impact of obesity on lipid metabolism in different types of primary hyperlipidemias. Obesity is not common in primary (familial and polygenic) hypercholesterolemias, and insulin resistance is infrequent; various investigators have found no or only a weak association between plasma cholesterol concentrations and insulin levels. On the other hand, in familial hypertriglyceridemia (type IV) and familial combined hyperlipidemia (FCH), obesity and insulin resistance are common and, when present, contribute to a further deterioration in the lipid profile. Weight loss in most of these patients is accompanied by a significant decrease in plasma triglyceride levels and an increase in HDL-C. Reviewing the data published by our group, we show that insulin resistance is an important component of the metabolic derangement in FCH subjects; high fasting plasma free fatty acids and triglycerides levels correlate to insulin resistance, thus linking this abnormality to lipid metabolism. A high waist/hip ratio (indicating visceral fat deposits) exacerbates insulin resistance, but this is also present in lean FCH subjects. Furthermore, insulin resistance is associated with a higher prevalence of coronary heart disease in this group of subjects.

Ascaso JF, Real JT, Carmena R. · Hospital Clínico Universitario, Department of Medicine, University of Valencia, Spain. · Diabetes Obes Metab. · Pubmed #11225648 No free full text.

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Chaves FJ, Real JT, García-García AB, Civera M, Armengod ME, Ascaso JF, Carmena R. · Institute of Cytological Research, Service of Endocrinology and Nutrition, Hospital Clínico Universitario, University of Valencia, Avda. Blasco Ibáñez 17, E-46010 Valencia, Spain. · J Clin Endocrinol Metab. · Pubmed #11600564 links to  free full text

Abstract: The aims of this study were to examine the presence of mutations in the low-density lipoprotein receptor gene among subjects clinically diagnosed with familial hypercholesterolemia and to analyze whether the molecular diagnosis helps to predict the response to simvastatin treatment in our familial hypercholesterolemia population. Fifty-five probands and 128 related subjects with familial hypercholesterolemia were studied. Genetic diagnosis was carried out following a three-step protocol based on Southern blot and PCR-single strand conformational polymorphism analysis. A randomized clinical trial with simvastatin was conducted in 42 genetically diagnosed subjects with familial hypercholesterolemia classified as carriers of null mutations (n = 22) and of defective mutations (n = 20). A mutation-causing familial hypercholesterolemia was identified in 46 probands (84%). In 41 of them (89%), a total of 28 point mutations were detected, 13 of which have not been previously described. The remaining five probands (11%) were carriers of large rearrangements. Familial hypercholesterolemia with null mutations showed a poor response to simvastatin treatment. The mean percentage reduction of plasma total and low-density lipoprotein cholesterol levels in these subjects were significantly lower (24.8 +/- 10.3 vs. 34.8 +/- 10.9, P = 0.04 and 30.0 +/- 39.8 vs. 46.1 +/- 18.2, P = 0.02, respectively) than in subjects with defective mutations. Baseline and posttreatment high-density lipoprotein cholesterol plasma values were significantly lower in subjects with familial hypercholesterolemia with null mutations (P < 0.001). In an outbreed Caucasian population, a three-step protocol for genetic screening detected a mutation in the low-density lipoprotein receptor gene in a high percentage (84%) of subjects with familial hypercholesterolemia. Subjects with familial hypercholesterolemia with null mutations (class I) showed lower plasma high-density lipoprotein cholesterol values and a poor low-density lipoprotein cholesterol response to simvastatin treatment.

Real JT, Chaves FJ, Civera M, García-García AB, Ascaso JF, Armengod ME, Carmena R. · Servicio de Endocrinología y Nutrición. Hospital Clínico Universitario. Departamento de Medicina. Universidad de Valencia. · Med Clin (Barc). · Pubmed #11181283 No free full text.

Abstract: BACKGROUND: To analyse whether the molecular diagnosis in FH patients is useful to predict the response to treatment with simvastatin in a south European population. SUBJECTS AND METHOD: A randomised clinical trial with no control group, with 20 mg/day of simvastatin was conducted in 27 genetically diagnosed FH subjects (11 male) from 8 FH families, randomly selected from 30 FH families with a molecular diagnosis. Clinical features and lipid parameters at baseline and after simvastatin treatment were compared between subjects classified as null mutations (FH Valencia 1 and 2; n = 11) and defective mutations (n = 16). RESULTS: FH with null mutations (FH Valencia 1 and 2) have a poor response to simvastatin treatment. The mean reduction of plasma LDLc levels in subjects with null mutations were significantly lower (32.6% [9.5] vs 42.8% [12.2]; p = 0.03) than in subjects with defective mutations. Baseline and after treatment plasma HDLc values were also significantly lower in FH group with null mutations. No statistically significant differences were found at baseline, after treatment and in the response to treatment between males and females. CONCLUSIONS: FH subjects with null alleles (FH Valencia 1 and 2) showed a poor response to simvastatin treatment. The type of LDL receptor gene mutation could predict the response to simvastatin in our south European FH population.

Real JT, Ascaso JF, Chaves FJ, Tenés S, Priego MA, Puig O, Armengod ME, Carmena R. · Endocrine Service, Hospital Clinico Universitario, University of Valencia, Spain. · Nutr Metab Cardiovasc Dis. · Pubmed #10726108 No free full text.

Abstract: BACKGROUND AND AIM: To analyze plasma Lp(a) levels and examine different risk factors and coronary heart disease (CHD) in a sample of genetically diagnosed familial hypercholesterolemia (FH) patients. METHODS AND RESULTS: Ninety heterozygous FH patients and 41 non-FH relatives were enrolled in a study to evaluate their plasma and lipoprotein cholesterol, as well as their triglyceride and Lp(a) levels. We found no differences in plasma Lp(a) levels and log transformed values between 90 FH subjects and their 41 unaffected relatives (22.3 mg/dl +/- 19.4 vs 17.7 mg/dl +/- 21.3 and 1.12 +/- 0.5 vs 0.96 +/- 0.54) nor between null allele and defective allele FH subjects (log Lp (a) levels 2.013 +/- 0.282 vs 1.959 +/- 0.151). FH CHD+ were significantly older, and had higher mean systolic and diastolic blood pressure and higher mean plasma triglyceride levels than FH CHD-. No differences in mean and log transformed Lp(a) plasma concentrations were found. CONCLUSIONS: Plasma Lp(a) levels are not related to LDL receptor status and class mutations, nor to the presence of CHD in FH patients.

Blesa S, Vernia S, Garcia-Garcia AB, Martinez-Hervas S, Ivorra C, Gonzalez-Albert V, Ascaso JF, Martín-Escudero JC, Real JT, Carmena R, Casado M, Chaves FJ. · Laboratorio de Estudios Genéticos, Fundación de Investigación Hospital Clínico, Universitario de Valencia, Avda. Blasco Ibáñez 17, E-46010 Valencia, Spain. · J Clin Endocrinol Metab. · Pubmed #18559913 No free full text.

Abstract: CONTEXT: Autosomal dominant hypercholesterolemia (ADH) is a genetic disorder characterized by increased low-density lipoprotein (LDL)-cholesterol levels, leading to high risk of premature cardiovascular disease. More than 900 mutations in LDL receptor, six in APOB and 10 in PCSK9 have been identified as a cause of the disease in different populations. All known mutations in PCSK9 causing hypercholesterolemia produce an increase in the enzymatic activity of this protease. Up to now, there are data about the implication of PCSK9 in ADH in a low number of populations, not including a Spanish population. OBJECTIVE: The objective of the study was to study the prevalence of PCSK9 mutations in ADH Spanish population. PARTICIPANTS: We screened PCSK9 gene in 42 independent ADH patients in whom mutations in LDL receptor and APOB genes had been excluded. RESULTS: None of the known mutations causing ADH was detected in our sample, but we found two variations in the promoter region that could cause ADH, c.-288G>A and c.-332C>A (each in one proband). The analysis of the effect of these two variations on the transcription activity of the PCSK9 promoter showed that c.-288G>A did not modify the transcription, whereas c.-332C>A variant caused a 2.5-fold increase when compared with the wild-type sequence, either with or without lovastatin. CONCLUSIONS: PCSK9 is a rare cause of ADH in Spanish population and, up to what we know, none of the previously described mutations has been detected. We have identified a new mutation that could cause ADH by increasing the transcription of PCSK9.

Ejarque I, Real JT, Martinez-Hervas S, Chaves FJ, Blesa S, Garcia-Garcia AB, Millan E, Ascaso JF, Carmena R. · Service of Endocrinology and Nutrition, Hospital Clinico Universitario, Department of Medicine, University of Valencia, Valencia, Spain. · Transl Res. · Pubmed #18279815 No free full text.

Abstract: Familial hypercholesterolemia (FH) and familial defective apoB 100 (FDB) are characterized by increased plasma low-density lipoprotein cholesterol (LDLc) levels and risk of coronary heart disease (CHD). FDB is clinically indistinguishable from FH. The aims of this study were to evaluate clinical diagnosis criteria for FDB and to compare the lipoprotein phenotype between carriers of LDL receptor (LDLR) gene mutations that affect the ligand-binding domain and subjects with the R3500Q mutation in apoB gene. We studied 213 subjects (113 probands) with FH and 19 heterozygous FDB subjects. Genetic diagnosis was determined by following a protocol based on Southern blot and polymerase chain reaction-single strand conformation polymorphism (SSCP) analysis. Thirty FH carriers of LDLR gene missense mutations that affect ligand-binding domain were matched by age, gender, and body mass index to the 19 FDB subjects (R3500Q mutation). Lipoprotein phenotype comparison was conducted between the 2 groups. FH patients showed plasma total and LDL cholesterol levels significantly higher than those in FDB patients. Three FDB showed plasma total and LDLc values in the normal range. Using the 1999 clinical Med-Ped criteria for diagnosis of genetic hypercholesterolemia, no FDB subjects had a confirmed diagnosis; it was probable in 36% of the subjects, it was possible in 32% of the subjects, and it could be excluded in the remaining 32% of the subjects. We conclude that the FDB lipoprotein phenotype was significantly less severe than that observed in FH carriers of LDLR gene missense ligand-binding domain mutations. Clinical Med-Ped diagnosis criteria tend to under-diagnose FDB.

Martinez-Hervas S, Fandos M, Real JT, Espinosa O, Chaves FJ, Saez GT, Salvador A, Cerdá C, Carmena R, Ascaso JF. · Department of Medicine, Service of Endocrinology and Nutrition, Hospital Clinico Universitario de Valencia, University of Valencia, Av Blasco Ibanez 15, 46010 Valencia, Spain. · Atherosclerosis. · Pubmed #18164710 No free full text.

Abstract: Oxidative stress is associated with atherosclerosis. Familial combined hyperlipidemia (FCH) is considered as a human model of primary dyslipidemia and atherosclerosis frequently associated with insulin resistance (IR), but there are few data on its possible relation to oxidative stress. The objective of this study was to evaluate oxidative stress status using different markers in subjects with FCH assessing its possible correlation with anthropometric parameters and IR. This was a cross-sectional study. A cohort of 40 FCH patients (20 with IR (HOMA>or=3.2) and 20 without IR (HOMA<3.2)), and 20 healthy volunteers were included, all of them non-diabetic, normotensive and non-smokers. We measured lipid profile, glucose and insulin levels in plasma, HOMA, and representative indicators of oxidative stress such as 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG), reduced glutathione (GSH), oxidized glutathione (GSSG) and GSSG/GSH ratio in mononuclear cells. All parameters were determined at basal conditions with standard methodology in the three groups. All FCH subjects showed an increased status of oxidative stress compared to the control group. When the impact of IR was investigated, significant differences between groups were observed in terms of increased levels of 8-oxo-dG, GSSG and GSSG/GSH ratio in FCH subjects with IR indicating higher levels of oxidative stress in these patients. Correlation studies showed that 8-oxo-dG and GSSG/GSH ratio are independently related to IR with odds ratio of 3.5 and 7.4, respectively. We conclude that FCH is related to oxidative stress, especially in the presence of IR.

Rejas J, Bobes J, Arango C, Aranda P, Carmena R, Garcia-Garcia M. · Health Outcomes Research Department, Medical Unit, Pfizer España, Ava de Europa, 20-B, 28108, Alcobendas (Madrid), Spain. · Schizophr Res. · Pubmed #18063343 No free full text.

Abstract: OBJECTIVE: To analyze the concordance between standard and modified NCEP-ATP-III criteria for identification of metabolic syndrome (MS) in outpatients with schizophrenia. METHOD: We used the sample from a cross-sectional study carried out to ascertain the prevalence of MS in schizophrenia. Kappa agreement and the symmetry Kendall's tau-b coefficients were calculated in a post-hoc analysis, a long with McNemar test and logistic regression models. RESULTS: The study enrolled 1,452 consecutive outpatients. MS was found in 24.6% (95%CI: 22.4%-26.8%) using the standard criteria and in 25.5% (23.2%-27.7%) using the modified criteria. Agreement was high; kappa 0.81 (p<0.0001) and tau-b 0.81 (p<0.0001), with a McNemar value of 0.2325. Kappa coefficients varied between 1.0 and 0.76 in subgroups according to sex, age-group, severity of disease, and duration of therapy. CONCLUSIONS: MS in outpatients with schizophrenia may be assessed by either the standard or the modified NCEP ATP III criteria without losing reliability.

Martinez-Hervás S, Real JT, Priego A, Sanz J, Martín JM, Carmena R, Ascaso JF. · Servicio de Endocrinología y Nutrición, Hospital Clínico Universitario, Universidad de Valencia, Valencia, Spain. · Rev Esp Cardiol. · Pubmed #17144994 links to  free full text

Abstract: Our aim was to investigate the relationship between metabolic syndrome and cardiovascular disease (i.e., survivors of myocardial infarction) in patients with familial combined hyperlipidemia (FCH). We compared a group of 20 male patients with FCH who had survived a myocardial infarction with two other groups matched for age and body mass index, comprising 20 individuals with FCH who had not had a myocardial infraction and 20 control subjects. Plasma lipid, glucose, and insulin levels were determined. Metabolic syndrome was judged to present on the basis of World Health Organization (WHO) and National Cholesterol Education Program-Adult treatment panel (NCEP-ATPIII) criteria. Differences between the groups were evaluated using non-parametric tests and the association between ischemic coronary disease and other parameters was assessed by logistic regression analysis. According to WHO criteria, the metabolic syndrome was present in 19 FCH patients who had survived a myocardial infarction, in 11 individuals with FCH who had not had a myocardial infraction, and in six control subject (P<.001); the difference between FCH patients with and without myocardial infarction was significant (P<.01). Presence of the metabolic syndrome, as defined by WHO criteria, is a marker of cardiovascular risk in individuals with FCH.

Garcia-Garcia AB, Blesa S, Martinez-Hervas S, Mansego ML, Gonzalez-Albert V, Ascaso JF, Carmena R, Real JT, Chaves FJ. · Fundación de Investigación Hospital Clínico Universitario de Valencia, Laboratorio de Estudios Genéticos, Hospital Clínico Universitario de Valencia, University of Valencia, Valencia, Spain. · Hum Mutat. · Pubmed #16791839 No free full text.

Abstract: Methods presently employed for detection of large rearrangements have several drawbacks, such as the amount of sample and time required, technical difficulty, or the probability of false-negative carriers. Using the low-density-lipoprotein receptor (LDLR) gene, whose mutations are responsible for familial hypercholesterolemia (FH), we have developed a procedure to detect large rearrangements in this gene based on semiquantitative PCR, with important improvements as compared to previous methods. Our method covers the complete LDLR gene and introduces an internal control in the reaction. The procedure discriminates the four different large rearrangements (two deletions and two insertions) that we have used as positive mutation controls (Valencia-1 to -5). All altered exons from each rearrangement are identified. Furthermore, when families from probands carrying these large rearrangements (34 members) were analyzed, our results agreed with those obtained previously with Southern blot. We have also analyzed a sample of 110 unrelated FH probands and the method has correctly identified the two different large rearrangements present and insertions or deletions as small as 1 bp. In conclusion, the method we present allows the identification of large rearrangements affecting exons of the gene, including small insertions or deletions or complete gene deletion. In addition, it constitutes a first characterization step of rearrangements, and is easy to carry out fast, and can be applied to the analysis of any gene.

Bartual A, González C, Martínez Hervás S, Real JT, García García AB, Castro Cabezas M, Chaves FJ, Priego MA, Ascaso JF, Carmena R. · Servicio de Endocrinología y Nutrición, Hospital Clínico Universitario de Valencia, Departamento de Medicina, Universitat de Valencia, España. · Rev Clin Esp. · Pubmed #16750103 No free full text.

Abstract: INTRODUCTION: A new method based on self-measurement of diurnal capillary triglycerides (TG) facilitates the study of postprandial lipemia (PL). The objectives of our study are: to evaluate the effect of gender and obesity on PL measured by self-determination of diurnal capillary TG with Accutrend GCT in normolipidemic non-diabetic subjects and subjects with familial combined hyperlipidemia (FCH). MATERIAL AND METHODS: We studied 23 FCH subjects (10 males) and 45 normolipidemic non-diabetic subjects (29 males). All subjects self-determine 3 diurnal capillary TG profiles during a week. RESULTS: In normolipidemic non diabetic subjects significantly higher diurnal TG profiles and area under the curve of TG (AUCTGc) (25.25 +/-9.09 vs 19.71 +/- 6.16 mmolh/l) were found in males compared to females. In FCH subjects these differences were not found and the AUCTGc correlated with BMI (r = 0.510, p < 0.05) and waist circumference (r = 0.453, p < 0.05). Obese subjects (BMI >or= 27 kg/m2) showed diurnal TG profiles and AUCTGc significantly higher than the non-obese. DISCUSSION: Normolipidemic non diabetic females showed a lower PL compared to males, probably due to the effect of estrogens in PL metabolism. Obesity negatively influences PL in normolipidemic non diabetic subjects and subjects with FCH.

Blesa S, Garcia-Garcia AB, Martinez-Hervas S, Mansego ML, Gonzalez-Albert V, Ascaso JF, Carmena R, Real JT, Chaves FJ. · Laboratorio de Estudios Genéticos, Fundación de Investigación HCUV, Hospital Clínico Universitario de Valencia, Valencia, Spain. · Clin Chem. · Pubmed #16627557 links to  free full text

Abstract: BACKGROUND: Familial hypercholesterolemia (FH) is a frequent form of autosomal-dominant hypercholesterolemia that predisposes to premature coronary atherosclerosis. FH is caused by sequence variations in the gene coding for the LDL receptor (LDLR). This gene has a wide spectrum of sequence variations, and genetic diagnosis can be performed by 2 strategies. METHODS: Point variations and large rearrangements were screened along all the LDLR gene (promoter, exons, and flanking intron sequences). RESULTS: We screened a sample of 129 FH probands from the Valencian Community, Spain, and identified 54 different LDLR sequence variations. The most frequent (10% of cases) was 111insA, and 60% of the variants had a frequency as low as 1%. A previously described method for detection of known sequence variations in the Spanish population by DNA array analysis allowed the identification of only approximately 50% of patients with a variant LDLR gene and approximately 40% of the screened samples. CONCLUSION: Our results indicate that the adequate procedure to identify LDLR sequence variations in outbreed populations should include screening of the entire gene.

Barter PJ, Ballantyne CM, Carmena R, Castro Cabezas M, Chapman MJ, Couture P, de Graaf J, Durrington PN, Faergeman O, Frohlich J, Furberg CD, Gagne C, Haffner SM, Humphries SE, Jungner I, Krauss RM, Kwiterovich P, Marcovina S, Packard CJ, Pearson TA, Reddy KS, Rosenson R, Sarrafzadegan N, Sniderman AD, Stalenhoef AF, Stein E, Talmud PJ, Tonkin AM, Walldius G, Williams KM. · Heart Research Institute, Camperdown, Sydney, NSW, Australia. · J Intern Med. · Pubmed #16476102 No free full text.

Abstract: There is abundant evidence that the risk of atherosclerotic vascular disease is directly related to plasma cholesterol levels. Accordingly, all of the national and transnational screening and therapeutic guidelines are based on total or LDL cholesterol. This presumes that cholesterol is the most important lipoprotein-related proatherogenic risk variable. On the contrary, risk appears to be more directly related to the number of circulating atherogenic particles that contact and enter the arterial wall than to the measured concentration of cholesterol in these lipoprotein fractions. Each of the atherogenic lipoprotein particles contains a single molecule of apolipoprotein (apo) B and therefore the concentration of apo B provides a direct measure of the number of circulating atherogenic lipoproteins. Evidence from fundamental, epidemiological and clinical trial studies indicates that apo B is superior to any of the cholesterol indices to recognize those at increased risk of vascular disease and to judge the adequacy of lipid-lowering therapy. On the basis of this evidence, we believe that apo B should be included in all guidelines as an indicator of cardiovascular risk. In addition, the present target adopted by the Canadian guideline groups of an apo B <90 mg dL(-1) in high-risk patients should be reassessed in the light of the new clinical trial results and a new ultra-low target of <80 mg dL(-1) be considered. The evidence also indicates that the apo B/apo A-I ratio is superior to any of the conventional cholesterol ratios in patients without symptomatic vascular disease or diabetes to evaluate the lipoprotein-related risk of vascular disease.

González C, Real JT, Bartual A, Chaves FJ, García-García AB, Blesa S, Castro-Cabezas M, Ascaso JF, Carmena R. · Hospital Clínico Universitario de Valencia, Departamento de Medicina, Universidad de Valencia, Valencia, Spain. · Med Clin (Barc). · Pubmed #16216199 No free full text.

Abstract: BACKGROUND AND OBJECTIVE: We decided to evaluate the clinical and biochemical predictors of postprandial lipemia, measured as daylong capillarly triglycerides (TGc) profiles, in normolipidemic non diabetic subjects. PATIENTS AND METHOD: We studied 76 normolipidemic non diabetic subjects (45 premenopausal females). Accutrend was used to measure daylong TGc profiles during 3 days in 6 previously standardized points: fasting, pre and 3 h after dinner and lunch and at bedtime. The area under the curve of TGc (AUC-TGc) was determined as expression of postprandial lipemia. RESULTS: Males showed significantly higher AUC-TGc (26.20 [11.00] vs 19.12 [6.57] in females; p < 0.001). Obese showed significantly higher values of AUC-TGc (27.87 [12.47] vs 20.05 [7.04]; p < 0.01). The AUC-TGc correlated with: age (r = 0.242; p < 0.05), body mass index (r = 0.312; p < 0.01), waist circumference (r = 0.394; p < 0.01), fasting plasma triglyceride (r = 0.634; p < 0.001), fasting insulinemia (r = 0.485; p < 0.001) and fasting HOMA (r = 0.484; p < 0.001). The multivariate analysis showed that HOMA (regression coefficient: 0.352; p = 0.02) and waist circumference (regression coefficient: 0.4; p = 0.05) were independent predictors of the AUC-TGc. CONCLUSIONS: Independent determinants of postprandial lipemia were waist circumference and HOMA.

García-García AB, González C, Real JT, Martín de Llano JJ, González-Albert V, Civera M, Chaves FJ, Ascaso JF, Carmena R. · Unidad Mixta de Investigación, Hospital Clínico Universitario de Valencia, Spain. · Pharmacogenet Genomics. · Pubmed #15864113 No free full text.

Abstract: Familial hypercholesterolaemia (FH) is an autosomal dominant disease characterized by elevated levels of low-density lipoprotein-cholesterol (LDL-C). Phenotypic expression is highly variable, being influenced by diet, age, gender, body mass index, apolipoprotein E genotype and type of LDL-receptor gene mutation. Microsomal triglyceride (TG) transfer protein (MTP) is a protein involved in lipid metabolism. Polymorphism MTP -493 GT has been shown to modulate lipid levels in several populations. To analyse the effect of this polymorphism in the lipid phenotype expression of FH and treatment response, we studied a sample of 222 Spanish FH patients, of whom 147 were studied before and after treatment with 20 mg of atorvastatin daily during 6 weeks. The variant was analysed by polymerase chain reaction amplification and single-strand confirmation polymorphism. Treatment reduced LDL-C, total cholesterol and TGs. Baseline fasting TGs and very-low-density lipoprotein cholesterol levels were lower in female T allele carriers (TG: 111+/-51 mg/dl GG, 89+/-35 mg/dl GT, 83+/-26 mg/dl TT, P=0.022; very-low-density lipoprotein cholesterol: 24+/-13 mg/dl GG, 16+/-5 mg/dl GT, 17+/-5 mg/dl TT, P=0.018). Triglyceride response to atorvastatin was modulated by this polymorphism in men (P=0.009), but not in women, although differences between genotypes were maintained after treatment. In conclusion, the MTP -493 GT polymorphism modulates pre- and post-treatment plasma TG values of FH in Spanish subjects in a gender-specific way. Other environmental and genetic factors likely also modulate this response.

van Oostrom AJ, Real JT, Carmena R, Ascaso JF, Castro Cabezas M. · Department of Vascular Medicine, Room F02.216, University Hospital Utrecht, P.O. Box 85500, 3508 GA Utrecht, The Netherlands. · Neth J Med. · Pubmed #15588068 links to  free full text

Abstract: BACKGROUND: A Mediterranean eating pattern and diet enriched in monounsaturated fatty acids may result in a favourable daylong lipid profile. METHODS: 19 Spanish males (aged 32 +/- 8 years) and 28 females (34 +/- 8 years) were matched to Dutch subjects on the basis of fasting capillary triglycerides (TGc), gender and age. TGc were self-measured at six fixed time points over three days. Daylong TGc profiles were calculated as areas under the curve (TGc-AUC). RESULTS: Anthropometric parameters and fasting plasma lipids were comparable between Spanish participants and Dutch subjects. Insulin sensitivity (expressed as HOMA) was highest in the Dutch females (1.41 +/- 1.09 vs. 2.09 +/- 1.23 in the Spanish females, p < 0.05). Daylong TGc values were not different between Spanish and Dutch participants. Male Spanish subjects showed the largest daylong TGc increase after lunch, while in the Dutch males, the largest TGc increase was seen after dinner. Total daytime dietary energy and total fat intake were comparable when analysed by gender. However, the Spanish participants had a higher intake of monounsaturated and polyunsaturated fatty acids as percentage of energy. CONCLUSION: There are no major differences in daylong triglyceridaemia between Dutch and Spanish subjects, despite different eating habits and a diet enriched in monounsaturated and polyunsaturated fat in the latter.

Ejarque I, Real JT, Chaves FJ, Blesa S, González V, Milian E, Ascaso JF, Priego MA, Carmena R. · Servicio de Endocrinología y Nutrición, Hospital Clínico Universitario, Departamento de Medicina, Universidad de Valencia, Valencia, Spain. · Med Clin (Barc). · Pubmed #15498441 No free full text.

Abstract: BACKGROUND AND OBJECTIVE: To compare the lipoprotein phenotype between FDB and heterozygous familial hypercholesterolemia (FH); to study the prevalence and possible founder effect of familial ligand-defective apo B100 (FDB) in a Mediterranean population, and to analyze the clinical and biochemical characteristics of FDB patients. SUBJECTS AND METHOD: We studied 19 heterozygous FDB subjects (8 males) from 12 related families, carriers of the R3500Q mutation on the apo B gene, and 57 heterozygous FH (24 males) genetically characterized, randomly selected from a total of 213 FH. The genetic diagnosis was established with Southern blot analysis, PCR-SSCP analysis and automatic sequencing. In all subjects, plasma lipids and apolipoprotein levels were determined with standard procedures. RESULTS: We demonstrated a founder effect for the R3500Q mutation in a geographically isolated rural area from our community. The prevalence of FDB in this area is high: 4/350. Heterozygous FDB subjects showed a statistical significantly lower prevalence of xanthomas and coronary heart disease, plasma concentrations of total and LDL cholesterol, HDL cholesterol, apo B and apo A-I values than heterozygous FH subjects. CONCLUSIONS: A founder effect for the R3500Q mutation was found in a rural population with a high prevalence of FDB. In our population, FDB patients showed a mild clinical expression and lipoprotein phenotype compared with FH patients.

Real JT, Chaves FJ, Ejarque I, García-García AB, Valldecabres C, Ascaso JF, Armengod ME, Carmena R. · Service of Endocrinology and Nutrition, Department of Medicine, Hospital Clínico Universitario, University of Valencia, Spain. · Eur J Hum Genet. · Pubmed #14508510 links to  free full text

Abstract: Few data are available on genotype-phenotype interactions among familial hypercholesterolemia (FH) patients in South European populations and there are no data about the influence of R3500Q mutation on lipoprotein phenotype compared to low-density lipoprotein receptor (LDLR) mutations. The objective of the study is to analyze the influence of mutations in the LDLR and apolipoprotein B (apoB) genes on lipoprotein phenotype among subjects clinically diagnosed of FH living in East Spain. In all, 113 FH index patients and 100 affected relatives were studied. Genetic diagnosis was carried out following a protocol based on Southern blot and PCR-SSCP analysis. A total of 118 FH subjects could be classified into three groups according to the type of LDLR mutations (null mutations, missense mutations affecting the ligand binding 3-5 repeat, and missense mutations outside this domain). In addition, the lipoprotein phenotype of these FH groups was compared with 19 heterozygous subjects with familial ligand-defective apoB (FDB), due to R3500Q mutation. FH patients carrying missense mutations affecting the ligand binding repeat 3-5 showed total and LDL cholesterol levels significantly higher than FH patients with missense mutations in other LDLR domains or FDB patients. FH subjects carrying null mutations showed lower high-density lipoprotein cholesterol plasma values compared to FH carrying missense mutations. FDB subjects showed the lowest total and LDL cholesterol plasma values. In conclusion, the type of LDLR gene mutation and R3500Q mutation influences the lipoprotein phenotype of FH population from East Spain.

Tai ES, Adiconis X, Ordovas JM, Carmena-Ramon R, Real J, Corella D, Ascaso J, Carmena R. · Nutrition and Genomics Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA. · Clin Genet. · Pubmed #12519372 No free full text.

Abstract: Scavenger receptor, class B, type 1 (SRBI) is a promising candidate gene involved in the pathophysiology of atherosclerosis. We have examined the association of three common polymorphisms at the SRBI locus in 77 subjects who were heterozygous for familial hypercholesterolemia (FH). The alleles represented by polymorphisms in exon 1 and exon 8 were associated with variation in plasma concentrations of fasting triglyceride (TG). Mean plasma TG concentrations for homozygotes for the most common allele, and for heterozygotes and homozygotes for the less common allele were 85 +/- 6, 111 +/- 9 and 135 +/- 22 mg/dl (p = 0.011) for exon 1, and 96 +/- 11, 86 +/- 6 and 134 +/- 13 mg/dl (p = 0.007) for exon 8, after adjustment for age, sex and body mass index. In addition, the exon 8 polymorphism was associated with increased total cholesterol (320 +/- 15, 340 +/- 8 and 388 +/- 18 mg/dl, p = 0.015), very low density lipoprotein (VLDL) cholesterol (18 +/- 2.9, 15.7 +/- 1.6 and 33.4 +/- 3.9 mg/dl, p < 0.001) and low density lipoprotein (LDL) cholesterol (251 +/- 15, 270 +/- 8 and 312 +/- 10 mg/dl, p = 0.041) concentrations. In agreement with animal studies, our data also suggest a role for the SRBI in the metabolism of apolipoprotein B (apoB)-containing lipoproteins in humans. This pathway may constitute a backup mechanism to LDL receptor-mediated pathways for the catabolism of these lipoproteins, which could be particularly relevant in subjects with high levels of apoB-containing lipoproteins, such as those occurring in patients with FH.

Real JT, Ascaso JF, Chaves FJ, González C, Puig O, Armengod ME, Carmena R. · Servicio de Endocrinología y Nutrición, Hospital Clínico Universitario, Departamento de Medicina, Universidad de Valencia, Spain. · Med Clin (Barc). · Pubmed #12042130 No free full text.

Abstract: BACKGROUND: Our goal was to analyze the relationship of lipids and lipoproteins, APOE genotype and mutations of the LDL receptor gene with the prevalence of myocardial infarction (MI) in patients with familial hypercholesterolemia (FH) from a Southern European FH population. PATIENTS AND METHOD: We studied 108 heterozygous FH subjects aged > 35 years (41 males). It was a cross-sectional study comparing individuals with FH and MI with individuals with FH without MI. In 88 FH subjects, a mutation of the LDL receptor gene was detected. These FH subjects were divided in carriers of null mutation or no null mutations. We compared lipids and lipoproteins and prevalences of LDL receptor type mutation and APOE genotype. RESULTS: Parameters associated with MI were: age, presence of xanthomas and arcus cornealis, plasma concentrations of total cholesterol (TC), LDLc, TC/HDLc ratio > 5.3 and *4 genotype of the APOE gene. Odds ratio for MI were as follows: presence of xanthomas and arcus cornealis, 1.36 (CI 95%, 1.08-1.71; P = 0.01), age > 54 years (50 th of FH group), 1.56 (CI 95%, 1.19-2.04; P = 0.001) and plasma TC values > 332 mg/dl (50 th of FH group), 1.34 (CI 95%, 1.05-1.71; P = 0.019). In the logistic regression model, only age and TC were significantly associated with MI. CONCLUSIONS: In FH subjects aged over 35 years from a Southern European population, MI is associated with age, plasma TC and LDLc values, TC/HDLc ratio and the *4 genotype. In addition, MI is related with age and TC plasma levels on an independent basis.

García-García AB, Real JT, Puig O, Cebolla E, Marín-García P, Martínez Ferrandis JI, García-Sogo M, Civera M, Ascaso JF, Carmena R, Armengod ME, Chaves FJ. · Instituto de Investigaciones Citológicas, Fundación Valenciana de Investigaciones Biomédicas, Valencia, Spain. · Hum Mutat. · Pubmed #11668640 No free full text.

Abstract: Mutations underlying FH in Spain are largely unknown because only a few and limited surveys have been carried out on Spanish FH patients up to now. To gain information on this issue, we have analysed a group of 113 unrelated Spanish FH patients from an eastern area of Spain (Valencian Community). We have screened the LDLR gene by Southern blot and PCR-SSCP analysis to detect large rearrangements and small mutations, respectively. In addition, we have screened the Apo B gene for mutations known to cause FDB by PCR-SSCP analysis. We have identified a total of 47 different mutations in the LDLR gene (5 large rearrangements, and 42 small mutations, which were characterized by DNA sequencing), 19 of which have not been described in other populations (Valencia-1 to -4, 112insA, P160R, 790DelATGA, 920insTCAG, G642E, and the ten novel mutations E246A, 884delT, I289T, S305F, Q328X, Y354C, I603del, 2312-3C>A, V779M, and N804K). Three of these mutations (15%) were present in more than 1 proband, being mutation 112insA the most prevalent (frequency approximately 8%) in our sample. The Apo B gene R3500Q mutation was found in only one patient and no underlying defect was found in about 27% of patients. Our data support the notion that Spaniards represent a heterogeneous population with its own spectrum of LDLR gene mutations and that, in our population, FDB has a lower frequency or a milder expression than in central Europe countries.

Carmena-Ramón R, Ascaso JF, Real JT, Nájera G, Ordovás JM, Carmena R. · Department of Medicine, Hospital Clínico Universitario, University of Valencia, Valencia, Spain. · Metabolism. · Pubmed #11398140 No free full text.

Abstract: Cholesteryl ester transfer protein (CETP) facilitates the exchange of triglycerides (TG) and cholesteryl ester between lipoprotein particles. Subjects with familial hypercholesterolemia (FH) have been reported to have higher CETP activities, which could contribute to the lower high-density lipoprotein-cholesterol (HDL-C) levels and increased cardiovascular risk observed in some of these patients. Several polymorphisms have been reported in the CETP locus; the common TaqlB polymorphism is associated, in normolipidemic subjects, with decreased CETP activity and levels and with increased HDL-C levels. No data is available on the influence of this polymorphism in FH subjects. We have examined the TaqIB polymorphism in a group of 101 FH heterozygotes from Valencia, Spain. We have observed a frequency of 0.43 for the B2 allele, similar to those reported in the general population. Based on analysis of variance (ANOVA), we found significant associations between the presence of the B2 allele and increased plasma HDL-C (P <.04) and apolipoprotein A-I (apoA-I) levels (P <.01). An opposite association was observed for low-density lipoprotein-cholesterol (LDL-C) levels, with the B2/B2 subjects having lower levels than B1/B1 and B1/B2 subjects. The plasma apoB levels followed the same trend as those for LDL-C. In addition, the response to a National Cholesterol Education Program (NCEP)-I diet was studied in 77 of these subjects. The TaqlB polymorphism did not have a significant effect over the individual dietary response for any of the variables examined, as demonstrated by the lack of significant gene by diet interactions. In summary, the CETP TaqlB polymorphism is associated with a less atherogenic lipid profile, consisting of lower LDL-C, higher HDL-C levels, and a lower LDL-C/HDL-C ratio in heterozygous FH subjects. Moreover, the B2 allele was associated with a lower appearance of arcus cornealis, xanthomata, and clinical arteriosclerotic disease in these subjects.

Chaves FJ, Real JT, García-García AB, Puig O, Ordovas JM, Ascaso JF, Carmena R, Armengod ME. · Fundación Valenciana de Investigaciones Biomédicas, Valencia, Spain. · Eur J Clin Invest. · Pubmed #11298777 No free full text.

Abstract: BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant disease caused by mutations in the low-density lipoprotein receptor (LDLR) gene. To date, there has not been a systematic survey of the frequency of gross mutations in the LDLR gene in the Spanish population. The objective of our study was to investigate large rearrangements in the Spanish FH population and the relation between the kind of large rearrangement and the phenotype in carrier families. MATERIALS AND METHODS: The LDLR gene was screened to detect major rearrangements in a sample of 89 probands. Southern blot, long polymerase chain reaction (PCR), reverse transcription (RT) -PCR and DNA sequencing were used to detect and characterize the mutations. RESULTS: Five large rearrangements were found in six probands. Two mutations were due to duplications of internal regions of the gene, whereas the rest were caused by partial deletions, which eliminated the promoter region in two cases. The internal rearrangements, two duplications and one deletion, were apparently caused by recombination between ALU sequences and the study of their mRNA indicated that the reading frame was maintained. The analysis of the lipid profile between patients with similar characteristics (age, sex, body mass index, etc.) but carrying mutations that either eliminated the promoter region or produced internal rearrangements showed significant differences (total cholesterol: 366.6 +/- 81.8 vs. 304.6 +/- 25.1 P = 0.023, and LDL cholesterol: 317.7 +/- 65.1 vs. 249.2 +/- 27.4 P = 0.003). CONCLUSIONS: The frequency of large mutations in a Spanish FH sample was close to 7% and at least four of the mutations found had not been described in other populations. Mutations that eliminate the promoter region originate more severe hypercholesterolemia than defective mutations, which suggests that the absence of the promoter region and transcription of the LDLR gene is worse compensated than the synthesis of a defective LDL receptor.