👤 M Guillén

Progression in Alzheimer's disease (AD) involves three main interrelated biological axes-tau deposition, neurodegeneration, and neuroinflammation-that jointly drive cognitive decline. Although several cerebrospinal fluid (CSF) and plasma biomarkers along these axes are well validated for diagnosis, their value for prognosis remains uncertain. We assessed how baseline markers of each axis predict cognitive trajectories in biomarker-confirmed AD. We included 136 A + T + N + individuals (median follow-up = 24 months [IQR 12-24]; mean = 17.6 months [SD = 12.4]). Tau-deposition markers (CSF p-Tau181; plasma p-Tau181 and p-Tau217), neurodegeneration markers (CSF t-Tau; CSF and plasma neurofilament light chain, NfL) and a neuroinflammation marker (plasma glial fibrillary acidic protein, GFAP) were quantified using CLEIA, ELISA or Simoa, and stratified into tertiles. Participants were classified by age at onset, clinical phenotype, and APOE ε4 status. Cognition was assessed annually with a comprehensive neuropsychological battery. Linear mixed-effects models (MMRM) were used to test biomarker-cognition associations and interactions with clinical variables. Elevated CSF p-Tau181 and NfL levels were associated with greater decline in memory and executive function. Among plasma biomarkers, p-Tau217 and GFAP showed the strongest associations with widespread cognitive decline, particularly in language, visuospatial, and executive domains. These associations were independent of age at onset, clinical phenotype, and APOE ε4 status. Our findings highlight the potential prognostic value of fluid biomarkers in AD, especially CSF p-Tau181 and NfL, and plasma p-Tau217 and GFAP. These results suggest promise for improving disease monitoring, although prognostic utility at the individual level remains uncertain. 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

Apolipoprotein (Apo) A5 is a protein involved in the activation of lipoprotein lipase (LPL) and the metabolism of triglyceride (TG)-rich lipoproteins. LPL plays a major role in the metabolism of TG-rich lipoproteins, and placental LPL activity is known to correlate positively with foetal fat deposition and size. We examine the association between the common APOA5 S19W polymorphism and neonatal anthropometrical measurements, lipoprotein and hormone concentrations, and insulin sensitivity in 58 normal weight Caucasian newborns from the Mérida cohort. Neonates with the W allele displayed lower BMI (P < 0.001), ponderal index (P < 0.001), birth weight (P < 0.01), insulin levels (P < 0.05), the insulin/cortisol ratio (P < 0.05), HOMA-R (P < 0.05) and Apo B values (P < 0.01), but higher oxidised LDL (LDLox) values and a higher LDLox/low-density lipoprotein (LDL) ratio (both P < 0.05) than S-homozygous newborns. The APOA5 S19W polymorphism was associated with foetal growth as well as with glucose and lipoprotein metabolism in the neonates. Concurrence of the S19W polymorphism in neonates and their mothers did not affect neonatal lipid and lipoprotein concentrations but was associated with impaired foetal growth. Specifically, W allele carriers displayed a higher degree of LDL oxidation and lower body weight, plasma insulin values, insulin/cortisol ratio and Apo B concentrations than homozygotes for the common S allele. In conclusion, these findings suggest that the W allele carriers received a less optimal nutrition during gestation and that their lipoprotein antioxidant status was inferior to that of their homozygous S allele counterparts. 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

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 A4 (apoA4) plays a role in intestinal lipid absorption. Several experimental interventions have shown that common variations at residues 347 (Thr --> Ser) and 360 (Gln --> His) on apoA4 are associated with differences in plasma lipid response to dietary fat; however, association studies between these variants and plasma lipid concentrations in populations reveal mixed results. We examined the effects of these polymorphisms in 758 randomly selected subjects (mean age 36.7+/-9.5 years) from 2 Spanish regions differing in latitude and fat intake: Aragón and Comunidad Valenciana. Subjects were matched one to one by sex and age. Frequencies for the less common alleles were similar in both regions: 0.096 (95% CI: 0.111-0.081) for codon 360 and 0.196 (95% CI: 0.216-0.176) for codon 347. In men and women there was no association between the codon 360 polymorphism and total cholesterol or triglyceride levels. However, subjects carrying the 360His allele had low-density lipoprotein (LDL) cholesterol concentrations statistically lower than homozygotes for the 360Gln allele, even after further adjustment for sex, age, region, body mass index, and APOE polymorphism (p = 0.043). The less common allele at codon 347 (the 347Ser allele) was associated with increased LDL-cholesterol concentrations with a clear gene-dosage effect after multivariate adjustment (p = 0.029). Although these polymorphisms showed no heterogeneity by geographic region, the magnitude of the effect was higher in subjects from Aragón compared with the Comunidad Valenciana, suggesting a possible influence of the higher fat intake in Aragón. In the combined association analysis subjects with the 360Gln/347Ser pseudohaplotype had the highest LDL-cholesterol concentrations, supporting the antagonistic effect between the 360His and the 347Ser alleles on this trait. Show less

We conducted a cross-sectional study in a Spanish population (n = 1,029) to investigate associations between the LPL and APOC3 gene loci (LPL-HindIII, LPL-S447X, and APOC3-SstI) and plasma lipid levels and their interaction with APOE polymorphisms and smoking. Carriers of the H(-) or the X447 allele had higher levels of HDL cholesterol (HDL-C), and lower levels of TG, after adjustment for age, body mass index, alcohol, smoking, exercise, and education (P < 0.01). The APOC3 polymorphism presented additive effects to the LPL variants on TG and HDL-C levels in men, and on TG in women. The most and the least favorable haplotype combinations were H(-)/X447/S1 and H(+)/S447/S2, respectively. These combinations accounted for 7% and 5% of the variation in HDL-C and TG in men, and 3% and 4% in women. There was a significant interaction between APOE and LPL variants and HDL-C levels in both genders (P < 0.05). The increases in HDL-C observed for the rare alleles were higher in epsilon4 than in epsilon3 subjects, and absent in epsilon2 individuals. This effect was modulated by smoking (interaction HindIII-APOE-smoking, P = 0.019), indicating that smoking abolished the increase in HDL-C levels observed in epsilon4/H(-) subjects. Understanding this gene-gene-environmental interaction may facilitate preventive interventions to reduce coronary artery disease risk. Show less