Alfonso J. Sarría

Understanding the role of dietary components on atherosclerosis using genetic engineered mouse models.

The generation by genetic engineering of two murine models to investigate atherosclerosis, such as the apoE- and LDLr- deficient mice, is providing an extraordinaire knowledge of the effect of different nutrients on this complex disease. The present revision provides a comprehensive overview of the advances in this field that point to a remarkable complexity. While some controversies over puzzling results could be explained invoking potential nutrient interactions or different food sources of nutrients, it also appears that other factors such as sex, genetic background or immunological status are emerging as generators of differential responses to nutrients during the atherosclerotic process.

Detection of three rare (G377S, T134P and 1451delAC), and two novel mutations (G195W and Rec[1263del55;1342G>C] in Spanish Gaucher disease patients

To study glucocerebrosidase mutations causing Gaucher disease, we have screened 30 apparently unrelated patients for the presence of 7 previous described mutations. N370S (1226A>G) was the most common mutation (43%), followed by L444P (1448T>C) (23%). To identify the other unknown mutations, we screened regions of the glucocerebrosidase gene (GBA), by SSCP and sequencing. These analyses allowed identification of one novel G195W (700G>T), and two rare T134P (517A>C) and G377S (1246G>A) missense mutations. Mutation T134P (517A>C) was present in a type I patient, while G195W (700G>T), was encountered in two patients (types I, and III). The prevalence of mutation G377S (1246G>A), previously undetected in Spain, was found to be high (8%) making it a good candidate for routine genetic screening in patients from Spanish descent. Two null mutations have been identified as well Rec[1263del55;1342G>C], and 1451delAC). The Rec[1263del55;1342G>C] is a novel chimeric allele in which the gene sequence between nucleotides 5878‐6272 [sequence numbering according to Horowitz et al.(1989)] has been replaced by the homologous region of the pseudogene, and consequently it carries the 1263del55 and D409H (1342G>C) mutations. The functional equivalence of this allele to a 1263del55 allele previously described, suggest the potencial existence of a group of four distinct 55bp deletion harboring alleles with identical clinical consequences. Hum Mutat 14:88, 1999.

Cysteinemia, rather than homocysteinemia, is associated with plasma apolipoprotein A-I levels in hyperhomocysteinemia: lipid metabolism in cystathionine β-synthase deficiency.

OBJECTIVE Genetic and dietary hyperhomocysteinemia has been found to decrease high density lipoproteins (HDL) and their apolipoprotein A1 (APOA1). To test the hypothesis that the presence of cysteine could normalize HDL levels in hyperhomocysteinemic cystathionine beta-synthase (Cbs)-deficient mice and that the inclusion of glycine would block this effect. METHODS Lipids and HDL cholesterol were studied in Cbs-deficient mice and wild-type animals fed a low-methionine diet supplemented with cysteine and glycine and in Cbs-deficient mice on the same diet supplemented only with cysteine. RESULTS Triglyceride and homocysteine levels were significantly decreased and increased, respectively in Cbs-deficient mice irrespective of treatment. However, plasma cholesterol, glucose and APOA1 were significantly decreased in homozygous Cbs-deficient mice when they received the cysteine and glycine-enriched beverage. This group of mice also showed decreased mRNA levels and increased hepatic content of APOA1 protein, the latter increase was observed in endothelial cells. A significant, inverse relationship was observed between plasma and hepatic APOA1 concentrations while a positive one was found between plasma levels of cysteine and APOA1. CONCLUSION These data suggest an altered hepatic management of APOA1 and that cysteine may be involved in the control of this apolipoprotein at this level. Overall these findings represent a new aspect of dietary regulation of HDL at the hepatic transendothelial transport.

Genetically based hypertension generated through interaction of mild hypoalphalipoproteinemia and mild hyperhomocysteinemia.

Background 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. Methods and results Four groups of male mice were used: a control wild-type group; a group of mice heterozygous for cystathionine β-synthase deficiency; a group of mice heterozygous for apolipoprotein A-I deficiency; and, finally, a group of double heterozygous mice, with both cystathionine β-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. Conclusions 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.

Detection of three rare (G377S, T134P and 1451delAC), and two novel mutations (G195W and Rec[1263del55;1342G>C]] in Spanish Gaucher disease patients. Mutation in brief no. 251. Online.

In order to obtain novel mutations in the recently discovered Wilson disease gene, we screened 5 unrelated German individuals for mutations in the 21 exons and their flanking intronic sequences. We detected 9 mutations affecting the Wilson disease gene. Four of those, designated 802‐808delTGTAAGT, 2008‐2013delTATATG, Cys985Thr, and Ile1148Thr have not yet been reported. One patient had a homozygous mutation whereas the remaining four subjects were compound heterozygous. Therefore these data confirm, that mutations causing Wilson disease are frequently found in affected subjects and they are very heterogenous. Hum Mutat 14:88, 1999.

Animales de experimentación utilizados como modelos en la investigación de la arteriosclerosis

La presente revision aborda el metabolismo lipoproteico comparado y la induccion de la aterosclerosis con sus controversias en varios modelos animales pertenecientes a un amplio espectro evolutivo que abarca desde los roedores (raton, conejo, rata, hamster, cobaya), las aves (paloma), los cetartiodactilos (cerdo) y los carnivoros (perro) hasta los primates (macacos, Rhesus, mono verde africano).