👤 Édgar Navarro

The central nervous system (CNS) is a common site of metastatic spread for both non-small cell and small cell lung cancer, yet the therapeutic strategies to prevent and decrease lung cancer brain metastases remain limited. Tyrosine kinase inhibitors have shown promising results in increasing the overall response in brain metastases, owing to their brain penetrance and increased effectiveness; however, their use is limited to the small group of tumors carrying specific oncogenic drivers. Among these, inhibitors with activity against neurotrophic tyrosine receptor kinases (NTRKs) are showing promising effects in reducing CNS metastases in cancers driven by gene rearrangements of these drugs' targets. However, wild-type NTRKs are susceptible to activation by their canonical ligands, which are expressed throughout the brain metastatic niche and can, in a paracrine manner, activate NTRK function in cancer cells. Here we show that NTRKs are expressed in primary tumors, brain metastases, and lung cancer cells with various driver mutations expressing wild-type NTRK2 (WT-TrkB). We demonstrate that WT-TrkB activates downstream signaling and proliferation in response to exogenous BDNF and conditioned media from reactive astrocytes known to secrete BDNF in the brain niche. Importantly, the FDA-approved NTRK inhibitor entrectinib blocked BDNF and astrocyte-induced survival pathways in multiple lung cancer cell lines, decreased their proliferation These studies demonstrate that NTRK wild-type receptors are important drivers of brain metastatic colonization and progression in different subtypes of lung cancer, independent of their driver alterations. Thus, they provide rationale to expand the use of FDA-approved NTRK inhibitors with brain penetrance for the prevention of CNS metastases. Show less

Cerebrospinal fluid amyloid beta 42, total tau, and phosphorylated tau 181 are well accepted markers of Alzheimer's disease. These biomarkers better reflect disease pathogenesis compared to clinical diagnosis. Here, we perform a genome wide association study meta-analysis including 18,948 individuals of European ancestry and identify 12 genome-wide significant loci across all three biomarkers, eight of them novel. We replicate the association of biomarkers with APOE, CR1, GMNC/CCDC50 and C16orf95/MAP1LC3B. Novel loci include BIN1 for amyloid beta and GNA12, MS4A6A, SLCO1A2 with both total tau and phosphorylated tau 181, as well as additional loci on chr. 8, near ANGPT1 and chr. 9 near SMARCA2. We also demonstrate that these variants have significant association with Alzheimer's disease risk, disease progression and/or brain amyloidosis. The associated genes are implicated in lipid metabolism independent of APOE, coupled with autophagy and brain volume regulation driven by total tau and phosphorylated tau 181 dysregulation. Show less

The brain is vulnerable to DNA damage and cardiometabolic risk. Yet, whether genetic variation in DNA repair interacts with cardiometabolic factors to explain cognitive variability remains unclear. Participants (n = 376,533) of white-British ancestry from the UK biobank with cognitive, neuroimaging, and whole-exome sequencing data were included. Six cognitive outcomes were assessed: fluid intelligence (FIQ), symbol-digit matching task (SDMT), visual matching (MATCH), trail making (TRAIL1 and TRAIL2), and prospective memory (PMEM). Seven brain regions of interest were assessed: total brain (TBV), grey matter (GMV), left and right white matter (LWM/RWM), left and right hippocampi (LHC/RHC), and white matter hyperintensities (WMH) volumes. A total of 3487 genetic variants across 39 DNA repair genes were tested. SNP and gene/gene-set level associations were tested using regression models adjusted for age, sex, APOE ε4, ancestry, and outcome-specific covariates. Genetic interactions with a multidimensional cardiometabolic risk index (CMRI), encompassing established risk factors, were assessed. We detected 107 genetic variants (mostly extremely rare) across 36 DNA repair genes associated at Bonferroni-significance (p ≤ 1.4 × 10 Show less

Alzheimer's disease (AD) is a progressive neurodegenerative condition in which genetic predisposition plays a key role, yet the sex-specific mechanisms linking genetic risk to early cognitive changes remain unclear. This study examined the impact of polygenic risk scores (PRS) on early cognitive changes in 318 cognitively unimpaired participants from the ALFA+ cohort, a nested longitudinal cohort from the ALFA study (see details in Study Participants Section, Methods). Participants were followed for three years, with assessments across five cognitive domains and a preclinical composite (PACC). Global AD PRS, including and excluding the apolipoprotein E (APOE) gene, alongside five biologically informed pathway-specific PRS (amyloid, immune, external stimuli signaling, cholesterol efflux, lipoprotein metabolism) were computed. Generalized linear models including interaction by sex and stratified by sex and amyloid status (CSF Aβ42/40 < 0.071) assessed associations between PRS and cognitive change. In women, APOE-independent AD genetic risk predicted worse executive function, particularly via cholesterol efflux and external stimuli signaling pathways. Among Aβ + women, PRS also predicted lower memory performance, partially modulated by reproductive span. In Aβ - women, worse executive functioning performance was linked to amyloid, immune, and signaling pathways. In contrast, men showed associations between AD PRS and worse visual (Aβ-) and attentional (Aβ+) performance, independent of pathway-specific mechanisms. These findings reveal distinct, domain-specific cognitive vulnerabilities to AD genetic risk by sex and amyloid status, highlighting APOE-independent and mechanistic contributions to early and subtle cognitive changes. Results support the need for sex-aware, biologically informed genetic models in preclinical AD for risk stratification and early intervention. Show less

Monocytes and regulatory noncoding RNAs play a crucial role in the development of atherosclerosis (ATH). We have previously shown that miR-125b-5p was upregulated in aortic macrophages, and the aim of this paper was to further study the "in vivo" impact of miR-125b-5p in ATH progression. Eight-weeks-old Show less

Energy expenditure (EE) is essential for metabolic homeostasis, yet its central regulation remains poorly understood. Here, we identify arcuate Kiss1 neurons as key regulators of EE in male mice. Ablation of these neurons induced obesity, while their chemogenetic activation increased brown adipose tissue (BAT) thermogenesis without affecting food intake. This action is mediated by glutamatergic projections from Kiss1 Show less

Susceptibility to obesity differs depending on the genetic background and housing temperatures. We have recently reported that CETP expressing female mice are leaner due to increased lipolysis, brown adipose tissue (BAT) activity, and body energy expenditure compared to nontransgenic (NTg) littermates under standard housing temperature (22°C). The aim of this study is to evaluate how CETP expression affects body temperature, composition, and metabolism during cold exposure (4°C) and thermoneutrality (30°C). When submitted to cold, CETP mice maintained rectal temperature, body weight, and food intake similarly to NTg mice along acute or chronic exposure to 4°C. The body oxygen consumption in response to an isoproterenol challenge was 21% higher at 22°C, and 41% higher after 7 days of cold exposure in CETP than in NTg mice. In addition, BAT biopsies from CETP mice showed reduced lipid content and increased basal oxygen consumption rates. Under thermoneutrality (30°C), when BAT activity is inhibited, CETP mice showed higher rectal and tail temperatures, increased food intake, and increased energy expenditure. Lean mass was elevated and fat mass reduced in CETP mice kept at 30°C. In this thermoneutral condition, soleus muscle, but not gastrocnemius or liver of CETP mice, showed increased mitochondrial respiration rates. These data indicate that CETP expression confers a greater capacity of elevating body metabolic rates at both cold exposure, through BAT activity, and at thermoneutrality, through increased muscle metabolism. Thus, the CETP expression levels in females should be considered as a new influence in the contexts of obesity and metabolic disorders propensity. Show less

High-fat diets (HFDs) enhance fish growth by optimizing nutrient utilization (i.e., protein-sparing effect); however, their potential negative effects have also encouraged the search for feed additives. This work has investigated the effects of an extract rich in a polyphenolic antioxidant, hydroxytyrosol (HT), supplemented (0.52 g HT/kg feed) in a HFD (24% lipid) in gilthead sea bream ( Show less

A comprehensive international consensus on the cytogenetic risk-group stratification of KMT2A-rearranged (KMT2A-r) pediatric acute myeloid leukemia (AML) is lacking. This retrospective (2005-2016) International Berlin-Frankfurt-Münster Study Group study on 1256 children with KMT2A-r AML aims to validate the prognostic value of established recurring KMT2A fusions and additional cytogenetic aberrations (ACAs) and to define additional, recurring KMT2A fusions and ACAs, evaluating their prognostic relevance. Compared with our previous study, 3 additional, recurring KMT2A-r groups were defined: Xq24/KMT2A::SEPT6, 1p32/KMT2A::EPS15, and 17q12/t(11;17)(q23;q12). Across 13 KMT2A-r groups, 5-year event-free survival probabilities varied significantly (21.8%-76.2%; P < .01). ACAs occurred in 46.8% of 1200 patients with complete karyotypes, correlating with inferior overall survival (56.8% vs 67.9%; P < .01). Multivariable analyses confirmed independent associations of 4q21/KMT2A::AFF1, 6q27/KMT2A::AFDN, 10p12/KMT2A::MLLT10, 10p11.2/KMT2A::ABI1, and 19p13.3/KMT2A::MLLT1 with adverse outcomes, but not those of 1q21/KMT2A::MLLT11 and trisomy 19 with favorable and adverse outcomes, respectively. Newly identified ACAs with independent adverse prognoses were monosomy 10, trisomies 1, 6, 16, and X, add(12p), and del(9q). Among patients with 9p22/KMT2A::MLLT3, the independent association of French-American-British-type M5 with favorable outcomes was confirmed, and those of trisomy 6 and measurable residual disease at end of induction with adverse outcomes were identified. We provide evidence to incorporate 5 adverse-risk KMT2A fusions into the cytogenetic risk-group stratification of KMT2A-r pediatric AML, to revise the favorable-risk classification of 1q21/KMT2A::MLLT11 to intermediate risk, and to refine the risk-stratification of 9p22/KMT2A::MLLT3 AML. Future studies should validate the associations between the newly identified ACAs and outcomes and unravel the underlying biological pathogenesis of KMT2A fusions and ACAs. Show less

In teleost, as in other vertebrates, stress affects reproduction. A key component of the stress response is the pituitary secretion of the adrenocorticotropic hormone (ACTH), which binds to the melanocortin 2 receptor (MC2R) in the adrenal glands and activates cortisol biosynthesis. In zebrafish, Mc2r was identified in male and female gonads, while ACTH has been shown to have a physiological role in modulating reproductive activity. In this study, the hypothesis that other melanocortins may also affect how the zebrafish gonadal function is explored, specifically steroid biosynthesis, given the presence of members of the melanocortin signaling system in zebrafish gonads. Using cell culture, expression analysis, and cellular localization of gene expression, our new observations demonstrated that melanocortin receptors, accessory proteins, antagonists, and agonists are expressed in both the ovary and testis of zebrafish ( Show less

Introduction: Obesity is considered a serious public health problem. Efforts have been directed to search for candidate genes such as LEP, LEPR, and MC4R involved in the leptin-melanocortin system. The neuroendocrine regulation of these genes on energy intake and balance influences the pathogenesis of this disease. Contradictory results regarding the association of these genes with obesity raise the need for new research. Objective: To analyze the association between obesity and LEP rs2167270, LEPR rs1137101, and MC4R rs17782313 polymorphisms and the clinical and biochemical variables in obese adults from Barranquilla, Colombia. Materials and methods: We analyzed 111 obese adults and 155 non-obese individuals as controls. The polymorphisms were determined by real-time PCR. Besides, anthropometric measures, blood pressure, and biochemical tests were evaluated. Results: No statistical differences were found in allele and genotype frequencies of gene polymorphisms between groups. The CC genotype of MC4R rs17782313 polymorphism was associated with increased systolic blood pressure and T allele and TT genotype, with decreased HDL cholesterol in obese adults. The effect of the other polymorphisms on these variables was not evidenced. Conclusions: LEP rs2167270, LEPR rs1137101, and MC4R rs17782313 polymorphisms were not associated with obesity in the population under study. MC4R rs17782313 polymorphisms were associated with an increase in systolic blood pressure and a decrease in HDL cholesterol. Show less

To identify the genetic variants of the vascular endothelial growth factor (VEGF) pathway genes and other genes associated with neovascular age-related macular degeneration (nAMD) as possible predictive biomarkers of a favorable treatment response to aflibercept. A 52-week (with extension phase: 104-week), prospective, open-label, single-arm, multicenter, phase IV trial was conducted in Spain. Patients with nAMD were enrolled. Aflibercept was administered every 8 weeks until week 48 (after 1-monthly loading doses over 3 months). After week 48, the interval between visits for aflibercept administration was extended by 2 weeks per visit to a maximum of 12 weeks if no evidence of disease activity was observed. A total of 338 SNPs in 90 genes associated with nAMD were analyzed. Efficacy was evaluated mainly with best-corrected visual acuity (BCVA), and adverse events (AEs) were reported. Treatment efficacy was defined as an increase in BCVA ≥15 letters versus the baseline visit. Univariate and multivariate logistic regressions were used to associate single-nucleotide polymorphisms (SNPs) and treatment efficacy. 194 nonconsecutive patients were enrolled, 170 completed the 52-week follow-up, and of the 85 patients who started the extension phase, 77 completed this phase. Mean BCVA increased from baseline to weeks 52 and 104 by 9 and 10 letters (p = 0.0001 for both), respectively. The percentages of patients gaining ≥15 letters in weeks 52 and 104 were 33 and 31%, respectively. Multivariate logistic regression showed significant associations of 6 SNPs (in 6 genes) with treatment efficacy: rs12366035 (VEGFB; TT; odds ratio [OR] 217), rs25681 (C5; AA/AG; OR 19.7/8.3), rs17793056 (CX3CR1; CT/CC; OR 8.1/6.2), rs1800775 (CETP; CC; OR 6.6), rs2069845 (IL6; GG/AA; OR 5.6/3.3), and rs13900 (CCL2; CT; OR 4.0). One percent of the patients reported arteriothrombolic events related to aflibercept (cerebrovascular accident) according to the Antiplatelet Trialist Collaboration, and 2% reported serious ocular (retinal pigment epithelial tear, retinal tear, and endophthalmitis) and systemic (cardiac failure, hypersensitivity, and transient ischemic attack) AEs related to aflibercept. Results suggest strong pharmacogenetic associations between one genetic variant of VEGFB (TT, rs12366035) and C5 (AA, rs12366035) genes and the BCVA response after 52-week aflibercept treatment in patients with nAMD. Likewise, the results support the efficacy of aflibercept observed in phase III studies and a good safety profile. Show less

This paper summarizes the current understanding of the biology of somatostatin receptor (sst), role of immunotherapy in neuroendocrine tumor (NET), new agents for PPRT, and methods to assess response and clinical benefit in NET. One of the most interesting aspects of sst biology is the recent discovery of truncated variants of the sst5 receptor subtype with unique tissue distribution and response to somatostatin (SST). These truncated receptors are associated with bad patient prognosis, decreased response to SST analogs, and may be new targets for diagnoses and treatment. IFN remains a cost-effective agent, particularly in classic mid gut carcinoids, and there is interest to continue examining immunotherapy's in this disease. PRRT remains a key strategy for treatment and imaging. In addition to the classic agents, there are a series of new agents targeting other receptors such as the incretin receptors (GLP-1R; GIPR) and other G-protein coupled receptors with great potential. With regards to therapy monitoring, the most commonly used criteria are Response Criteria Evaluation in Solid Tumors (RECIST). However, for different reasons, these criteria are not very useful in NET. Incorporation of other criteria such as Choi as well as functional imaging assessment with PET would be of great interest in this area. Show less

Forced vital capacity (FVC), a spirometric measure of pulmonary function, reflects lung volume and is used to diagnose and monitor lung diseases. We performed genome-wide association study meta-analysis of FVC in 52,253 individuals from 26 studies and followed up the top associations in 32,917 additional individuals of European ancestry. We found six new regions associated at genome-wide significance (P < 5 × 10(-8)) with FVC in or near EFEMP1, BMP6, MIR129-2-HSD17B12, PRDM11, WWOX and KCNJ2. Two loci previously associated with spirometric measures (GSTCD and PTCH1) were related to FVC. Newly implicated regions were followed up in samples from African-American, Korean, Chinese and Hispanic individuals. We detected transcripts for all six newly implicated genes in human lung tissue. The new loci may inform mechanisms involved in lung development and the pathogenesis of restrictive lung disease. Show less

The present study was designed to verify the influence of acute fat loading on high density lipoprotein (HDL) composition, and the involvement of liver and different segments of small intestine in the changes observed. To address these issues, rats were administered a bolus of 5-ml of extra-virgin olive oil and sacrificed 4 and 8 hours after feeding. In these animals, lipoproteins were analyzed and gene expressions of apolipoprotein and HDL enzymes were assessed in duodenum, jejunum, ileum and liver. Using this experimental design, total plasma and HDL phospholipids increased at the 8-hour-time-point due to increased sphingomyelin content. An increase in apolipoprotein A4 was also observed mainly in lipid-poor HDL. Increased expression of intestinal Apoa1, Apoa4 and Sgms1 mRNA was accompanied by hepatic decreases in the first two genes in liver. Hepatic expression of Abcg1, Apoa1bp, Apoa2, Apoe, Ptlp, Pon1 and Scarb1 decreased significantly following fat gavage, while no changes were observed for Abca1, Lcat or Pla2g7. Significant associations were also noted for hepatic expression of apolipoproteins and Pon1. Manipulation of postprandial triglycerides using an inhibitor of microsomal transfer protein -CP-346086- or of lipoprotein lipase -tyloxapol- did not influence hepatic expression of Apoa1 or Apoa4 mRNA. All these data indicate that dietary fat modifies the phospholipid composition of rat HDL, suggesting a mechanism of down-regulation of hepatic HDL when intestine is the main source of those particles and a coordinated regulation of hepatic components of these lipoproteins at the mRNA level, independently of plasma postprandial triglycerides. Show less

Higher resting heart rate is associated with increased cardiovascular disease and mortality risk. Though heritable factors play a substantial role in population variation, little is known about specific genetic determinants. This knowledge can impact clinical care by identifying novel factors that influence pathologic heart rate states, modulate heart rate through cardiac structure and function or by improving our understanding of the physiology of heart rate regulation. To identify common genetic variants associated with heart rate, we performed a meta-analysis of 15 genome-wide association studies (GWAS), including 38,991 subjects of European ancestry, estimating the association between age-, sex- and body mass-adjusted RR interval (inverse heart rate) and approximately 2.5 million markers. Results with P < 5 × 10(-8) were considered genome-wide significant. We constructed regression models with multiple markers to assess whether results at less stringent thresholds were likely to be truly associated with RR interval. We identified six novel associations with resting heart rate at six loci: 6q22 near GJA1; 14q12 near MYH7; 12p12 near SOX5, c12orf67, BCAT1, LRMP and CASC1; 6q22 near SLC35F1, PLN and c6orf204; 7q22 near SLC12A9 and UfSp1; and 11q12 near FADS1. Associations at 6q22 400 kb away from GJA1, at 14q12 MYH6 and at 1q32 near CD34 identified in previously published GWAS were confirmed. In aggregate, these variants explain approximately 0.7% of RR interval variance. A multivariant regression model including 20 variants with P < 10(-5) increased the explained variance to 1.6%, suggesting that some loci falling short of genome-wide significance are likely truly associated. Future research is warranted to elucidate underlying mechanisms that may impact clinical care. Show less

Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes. Show less

The R820W mutation in the MYBPC3 gene has been associated with the development of hypertrophic cardiomyopathy (HCM) in rag-doll cats, but had not been described in humans. To describe the phenotype associated with the R820W mutation identified in a human family. The R820W was identified by direct sequencing of the MYBPC3 gene in a 47 year old woman with HCM and left ventricular non-compaction (LVNC). Clinical and genetic studies of the R820W mutation were performed in her family. The index patient was homozygous for the mutation and had no additional mutations in the main sarcomeric genes (MYH7, TNNT2, TNNI3, and TPM1). She had HCM with LVNC and normal systolic function. One brother had died suddenly at age 43 years. Another brother diagnosed of LVNC with severe systolic dysfunction and a cardiac arrest was also homozygous for the mutation. One heterozygous 31 year old sister, and three heterozygous sons of the index (ages 14, 20 and 23 years old) were clinically unaffected. The father of the index was apparently healthy and her mother had atrial fibrillation and an electrocardiographic diagnosis of left ventricular hypertrophy at age 86 years. The R820W mutation in the MYBPC3 gene, previously associated with HCM in rag-doll cats, causes both HCM and LVNC in homozygous human carriers, with mild or null clinical expression in heterozygous carriers. Show less

To identify loci for age at menarche, we performed a meta-analysis of 32 genome-wide association studies in 87,802 women of European descent, with replication in up to 14,731 women. In addition to the known loci at LIN28B (P = 5.4 × 10⁻⁶⁰) and 9q31.2 (P = 2.2 × 10⁻³³), we identified 30 new menarche loci (all P < 5 × 10⁻⁸) and found suggestive evidence for a further 10 loci (P < 1.9 × 10⁻⁶). The new loci included four previously associated with body mass index (in or near FTO, SEC16B, TRA2B and TMEM18), three in or near other genes implicated in energy homeostasis (BSX, CRTC1 and MCHR2) and three in or near genes implicated in hormonal regulation (INHBA, PCSK2 and RXRG). Ingenuity and gene-set enrichment pathway analyses identified coenzyme A and fatty acid biosynthesis as biological processes related to menarche timing. Show less

Fish are important sources of high quality protein, essential minerals such as iodine and selenium, vitamins including A, D and E, and omega-3 fatty acids in the human diet. With declining fisheries worldwide, farmed fish constitute an ever-increasing proportion of fish in the food basket. Sustainable development of aquaculture dictates that diets will have to contain increasing levels of plant products that are devoid of cholesterol, but contain phytosterols that are known to have physiological effects in mammals. Liver X receptors (LXR) are transcription factors whose activity is modulated by sterols, with activation inducing cholesterol catabolism and de novo fatty acid biosynthesis in liver. Transcriptomic analysis has shown that substitution of fish meal and oil with plant products induces genes of cholesterol and fatty acid metabolism in salmonids. Here we report the cloning of LXR cDNAs from two species of salmonid fish that are important in aquaculture. The full-length cDNA (mRNA) of LXR obtained from salmon was shown to be 3766 bp, which included a 5'-untranslated region (UTR) of 412 bp and a 3'-UTR of 1960 bp and an open reading frame (ORF) of 1394 bp, which specified a protein of 462 amino acids. The trout LXR full-length cDNA was 2056 bp, including 5'- and 3'-UTRs of 219 and 547 bp, respectively, and an ORF of 1290 bp, which specified a protein of 427 amino acids. The protein sequences included characteristic features of mammalian LXRs, including the DNA binding (DBD), containing P-box, ligand binding (LBD) and activation function-2 (AF-2) domains, D-box, D (hinge) region, and eight cysteines that belong to the two zinc fingers. Phylogenetic analysis clustered the salmonid LXRs together, more closely with zebrafish and more distantly from medaka and stickleback. A pair-wise comparison among vertebrate LXR sequences showed the amino acid sequence predicted by the salmon LXR ORF showed greatest identity to that of trout 97%, and 97%, 87% and 81% identity to LXRs of zebrafish, frog and human (LXRalpha). The trout LXR ORF showed 96%, 92% and 82% identity to LXRs of zebrafish, frog and human (LXRalpha). Surprisingly, the expression of LXR was lowest in liver of all tissues examined and in salmon the greatest expression was observed in pyloric caeca with liver showing intermediate expression. It is likely that tissue expression was affected by the physiological status of the sampled animals. Certainly, nutritional, environmental and/or developmental regulation was evident in salmon, where the expression of LXR in liver was higher in fish in seawater than in freshwater, and higher in fish fed fish oil compared to fish fed vegetable oil in adult salmon. Show less

Apolipoprotein A5 gene (APOA5) has been shown to modulate plasma triglyceride concentrations. The apolipoprotein E gene (APOE) has been implicated in cholesterol and triglyceride homeostasis in humans and plays an important role in atherogenesis. The aim of this study was to determine the genotypic distribution of the APOA5 -1131T>C and APOE polymorphisms and to identify the combined association of these variants between patients with and without severe hypertriglyceridemia (HTG). We genotyped 96 individuals who had reached plasma TG concentrations of more than 10 mmol/L and 225 ischemic patients without severe HTG. Minor allele carriers were significantly more frequent in HTG group for all three polymorphisms (APOA5, APOE2 and APOE4). Adjusted individual risks for severe HTG were: APOA5 -1131C, OR=4.1 (95%CI:2.02-8.24); APOE2, OR=1.6 (95%CI:0.73-3.58); APOE4, OR=3.0 (95%CI:1.68-5.86). Adjusted risks for APOA5-APOE combinations were: APOA5 -1131C/APOE2, OR=45.2 (95%CI:4.92-415.5); APOA5 -1131C/APOE4, OR=6.4 (95%CI:2.28-18.01). These data provide evidence that APOA5 -1131T>C polymorphism is associated with risk for severe HTG. Furthermore, this effect is strongly increased when -1131C variant is combined with APOE variants. Show less

Squalene is an intermediate of cholesterol biosynthesis which can be obtained from the diet where it is abundant, for example, in olive oil. The effect of this isoprenoid on the development of atherosclerosis was investigated on apoE-knockout mice. Two groups of animals, separated according to sex, were fed on standard chow diet: the control group receiving only vehicle and the second group an aqueous solution of squalene to provide a dose of 1g/kg/day in male and female mice. This treatment was maintained for 10 weeks. At the end of this period, plasma lipid parameters, oxidative stress markers and hepatic fat were measured as well as cross-sectional lesion area of aortic root in both groups. Data showed that in males squalene feeding reduced atherosclerotic lesion area independently of plasma lipids and activation of circulating monocytes. In contrast, squalene intake did not decrease lesion area in females, despite reducing plasma cholesterol and triglycerides, isoprostane and percentage of Mac-1 expressing white cells. In males, atherosclerotic lesion area was positively and significantly associated with hepatic fat content and the plasma triglycerides were also strongly associated with liver weight. These results indicate that administration of squalene modulates lesion development in a gender specific manner, and that accumulation of hepatic fat by liver is highly correlated with lesion progression in males. Hence, squalene administration could be used as a safe alternative to correct hepatic steatosis and atherosclerosis particularly in males. Show less

Hyperhomocysteinemia and hypoalphalipoproteinemia are two well-reported risk factors for cardiovascular disease. The effects of the synergistic combination of these two factors on vascular function need to be investigated. Four groups of male mice were used: a control wild-type group; a group of mice heterozygous for cystathionine beta-synthase deficiency; a group of mice heterozygous for apolipoprotein A-I deficiency; and, finally, a group of double heterozygous mice, with both cystathionine beta-synthase and apolipoprotein A-I deficiency. To characterize the resulting phenotype, several parameters including plasma apolipoproteins, lipid profiles, homocysteine, blood pressure and aortic protein were analyzed. As expected, our results indicate that double heterozygous mice are a model of mild hypoalphalipoproteinemia and hyperhomocysteinemia. Further, the additive combination of both risk factors resulted in a significant increase in blood pressure compared with control animals (136 +/- 8.0 versus 126 +/- 7.5 mm Hg, P < 0.01) that was not present in single heterozygous mice. The increase in blood pressure was associated with decreased plasma nitric oxide levels, left ventricle hypertrophy and was independent of low-density lipoprotein (LDL) cholesterol, para-oxonase activity and kidney histological changes. Concomitant decreases in levels of apolipoprotein A-IV (APOA-IV) and caveolin-1 content were also found in the double heterozygous group. Our findings suggest an additive adverse effect of hypoalphalipoproteinemia and hyperhomocysteinemia on endothelial function to generate clinical hypertension and cardiac muscle hypertrophy mediated by dysregulation in nitric oxide metabolism. Show less

To test the hypothesis that extra virgin olive oils from different cultivars added to Western diets might behave differently than palm oil in the development of atherosclerosis, apoE-deficient mice were fed diets containing different cultivars of olive oil for 10 weeks. Female mice were assigned randomly to one of the following five groups: (1-4) fed chow diets supplemented with 0.15% (w/w) cholesterol and 20% (w/w) extra virgin olive oil from the Arbequina, Picual, Cornicabra, or Empeltre cultivars, and (5) fed a chow diet supplemented with 0.15% cholesterol and 20% palm oil. Compared to diets containing palm oil, a Western diet supplemented with one of several varieties of extra virgin olive oil decreased atherosclerosis lesions, reduced plaque size, and decreased macrophage recruitment. Unexpectedly, total plasma paraoxonase activity, apoA-I, plasma triglycerides, and cholesterol played minor roles in the regulation of differential aortic lesion development. Extra virgin olive oil induced a cholesterol-poor, apoA-IV-enriched lipoparticle that has enhanced arylesterase and antioxidant activities, which is closely associated with reductions in atherosclerotic lesions. Given the anti-atherogenic properties of extra virgin olive oil evident in animal models fed a Western diet, clinical trials are needed to establish whether these oils are a safe and effective means of treating atherosclerosis. Show less

Apolipoprotein A-IV is a member of the apo A-I/C-III/A-IV gene cluster. In order to investigate its hypothetical coordinated regulation, an acute phase was induced in pigs by turpentine oil injection. The hepatic expression of the gene cluster as well as the plasma levels of apolipoproteins were monitored at different time periods. Furthermore, the involvement of the inflammatory mediators' interleukins 1 and 6 and tumor necrosis factor in the regulation of this gene cluster was tested in cultured pig hepatocytes, incubated with those mediators and apo A-I/C-III/A-IV gene cluster expression at the mRNA level was measured. In response to turpentine oil-induced inflammation, a decreased hepatic apo A-IV mRNA expression was observed (independent of apo A-I and apo C-III mRNA) not correlating with the plasma protein levels. The distribution of plasma apo A-IV experienced a shift from HDL to larger particles. In contrast, the changes in apo A-I and apo C-III mRNA were reflected in their corresponding plasma levels. Addition of cytokines to cultured pig hepatocytes also decreased apo A-IV and apo A-I mRNA levels. All these results show that the down-regulation of apolipoprotein A-I and A-IV messages in the liver may be mediated by interleukin 6 and TNF-alpha. The well-known HDL decrease found in many different acute-phase responses also appears in the pig due to the decreased expression of apolipoprotein A-I and the enlargement of the apolipoprotein A-IV-containing HDL. Show less