Contribution of genetic polymorphisms on functional status at very old age: a gene-based analysis of 38 genes (311 SNPs) in the oxidative stress pathway.

Preservation of functional ability is a well-recognized marker of longevity. At a molecular level, a major determinant of the physiological decline occurring with aging is the imbalance between production and accumulation of oxidative damage to macromolecules, together with a decreased efficiency of stress response to avoid or repair such damage. In this paper we investigated the association of 38 genes (311 SNPs) belonging to the pro-antioxidant pathways with physical and cognitive performances, by analyzing single SNP and gene-based associations with Hand Grip strength (HG), Activities of Daily Living (ADL), Walking Speed (WS), Mini Mental State Examination (MMSE) and Composite Cognitive Score (CCS) in a Cohort of 1089 Danish nonagenarians. Moreover, for each gene analyzed in the pro-antioxidant pathway, we tested the influence on longitudinal survival. In the whole sample, nominal associations were found for TXNRD1 variability with ADL and WS, NDUFS1 and UCP3 with HG and WS, GCLC and UCP2 with WS (p<0.05). Stronger associations although not holding the multiple comparison correction, were observed between MMSE and NDUFV1, MT1A and GSTP1 variability (p<0.009). Moreover, we found that association between genetic variability in the pro-antioxidant pathway and functional status at old age is influenced by sex. In particular, most significant associations were observed in nonagenarian females, between HG scores and GLRX and UCP3 variability, between ADL levels and TXNRD1, MMSE and MT1A genetic variability. In males, a borderline statistically significant association with ADL level was found for UQCRFS1 gene. Nominally significant associations in relation to survival were found in the female sample only with SOD2, NDUFS1, UCP3 and TXNRD1 variability, the latter two confirming previous observations reported in the same cohort. Overall, our work supports the evidence that genes belonging to the pro-anti-oxidant pathway are able to modulate physical and cognitive performance after the ninth decade of life, finally influencing extreme survival.

Health status and 6 years survival of 552 90+ Italian sib-ships recruited within the EU Project GEHA (GEnetics of Healthy Ageing).

In a scenario of increasing life expectancy worldwide, it is mandatory to identify the characteristics of a healthy aging phenotype, including survival predictors, and to disentangle those related to environment/lifestyle versus those related to familiarity/genetics. To this aim we comprehensively characterised a cohort of 1,160 Italian subjects of 90 years and over (90+, mean age 93 years; age range 90-106 years) followed for 6 years survival, belonging to 552 sib-ships (familiar longevity) recruited (2005-2008) within the EU-funded GEHA project in three Italian geographic areas (Northern, Central and Southern Italy) different for urban/rural and socio-economical characteristics. On the whole, the following factors emerged as significant predictors of survival after 90 years of age: absence of cognitive impairment and physical disability, high hand grip strength scores and body mass index (BMI) values, "excellent/good" self-reported health, high haemoglobin and total cholesterol levels and low creatinine levels. These parameters, excluding BMI values, were also significantly associated within sib-ships, suggesting a strong familial/genetic component. Geographical micro-heterogeneity of survival predictors emerged, such as functional and physical status being more important in Southern than in Central and Northern Italy. In conclusion, we identified modifiable survival predictors related to specific domains, whose role and importance vary according to the geographic area considered and which can help in interpreting the genetic results obtained by the GEHA project, whose major aim is the comprehensive evaluation of phenotypic and genetic data.

Design, recruitment, logistics, and data management of the GEHA (Genetics of Healthy Ageing) project.

In 2004, the integrated European project GEHA (Genetics of Healthy Ageing) was initiated with the aim of identifying genes involved in healthy ageing and longevity. The first step in the project was the recruitment of more than 2500 pairs of siblings aged 90 years or more together with one younger control person from 15 areas in 11 European countries through a coordinated and standardised effort. A biological sample, preferably a blood sample, was collected from each participant, and basic physical and cognitive measures were obtained together with information about health, life style, and family composition. From 2004 to 2008 a total of 2535 families comprising 5319 nonagenarian siblings were identified and included in the project. In addition, 2548 younger control persons aged 50-75 years were recruited. A total of 2249 complete trios with blood samples from at least two old siblings and the younger control were formed and are available for genetic analyses (e.g. linkage studies and genome-wide association studies). Mortality follow-up improves the possibility of identifying families with the most extreme longevity phenotypes. With a mean follow-up time of 3.7 years the number of families with all participating siblings aged 95 years or more has increased by a factor of 5 to 750 families compared to when interviews were conducted. Thus, the GEHA project represents a unique source in the search for genes related to healthy ageing and longevity.

Cognitive functioning and survival in the elderly: the SSADH C538T polymorphism.

The variability of the Succinic Semialdehyde Dehydrogenase (SSADH, or ALDH5A1) gene affects both pathological and normal phenotypes correlated to cognitive function. We tested the association between the C538T polymorphism of the SSADH gene and preservation of cognitive function in the elderly, and its possible effects on survival. A sample from southern Italy (514 subjects; 18-107 years) was screened for C538T variability. We found that, within the 65-85 years age range, the T/T genotype is overrepresented in subjects with impaired cognitive function (MMSE < or = 23) compared to those with conserved cognitive function (MMSE > 23). Furthermore, we found that the T/T genotype affects survival after 65 years of age. In fact, after this age, the survival function of T/T homozygous subjects is lower than that of the others. Given that the enzymatic activity of the protein encoded by allele T is 82.5% of the activity of the protein encoded by allele C, our results suggest that the efficiency of the SSADH enzyme is important for the preservation of cognitive function and survival in the elderly.

Characterization of a bidirectional promoter shared between two human genes related to aging: SIRT3 and PSMD13.

The human SIRT3 gene contains an intronic VNTR enhancer whose variability is correlated with life span. The SIRT3 5' flanking region encompasses the PSMD13 gene encoding the p40.5 regulator subunit of the 26S proteasome. Proteasome is a multicatalytic proteinase whose function declines with aging. SIRT3 and PSMD13 are linked in a head-to-head configuration (788-bp intergenic region). The molecular configuration of two genes that are both related to aging prompted us to search for shared regulatory mechanisms between them. Transfection experiments carried out in HeLa cells by deletion mutants of the PSMD13-SIRT3 intergenic region showed a complex pathway of coregulation acting in both directions. Furthermore, linkage disequilibrium (LD) analyses carried out in a sample of 710 subjects (18-108 years of age) screened for A21631G (marker of PSMD13), and for G477T and VNTR(intron5) (markers of SIRT3), revealed high LD, with significantly different PSMD13-SIRT3 haplotype pools between samples of centenarians and younger people.

Genes and longevity: a genetic-demographic approach reveals sex- and age-specific gene effects not shown by the case-control approach (APOE and HSP70.1 loci).

Association analyses between gene variability and human longevity carried out by comparing gene frequencies between population samples of different ages (case/control design) may provide information on genes and pathways playing a role in modulating survival at old ages. However, by dealing with cross-sectional data, the gene-frequency (GF) approach ignores cohort effects in population mortality changes. The genetic-demographic (GD) approach adds demographic information to genetic data and allows the estimation of hazard rates and survival functions for candidate alleles and genotypes. Thus mortality changes in the cohort to which the cross-sectional sample belongs are taken into account. In this work, we applied the GD method to a dataset relevant to two genes, APOE and HSP70.1, previously shown to be related to longevity by the GF method. We show that the GD method reveals sex- and age-specific allelic effects not shown by the GF analysis. In addition, we provide an algorithm for the implementation of a non-parametric GD analysis.

Postprandial hyperglycemia and hyperlipidemia-generated glycoxidative stress: its contribution to the pathogenesis of diabetes complications.

Postprandial glucose and triglyceride increments after a mixed meal are more prolonged in people with type 1 and 2 diabetes or with impaired glucose tolerance than in normal individuals. Evidence in the literature suggests that these transient increases represent an additional and independent risk for chronic hyperglycemia to induce endothelial dysfunction, an important fact for the development of diabetic vascular complications. This article presents the more relevant mechanisms by which acute postprandial hyperglycemia and hyperlipidemia have been proved to determine the risk of reactive oxygen species overproduction, an increased synthesis of non enzymatic early-glycated and nitrated proteins, and a more atherogenic lipoprotein profile. Recent recommendations suggest that care for this transient glycoxidative stress should be associated with fasting glucose or HbA1c care, to reduce the risk of macro- and microvascular complications in people with diabetes.

Variability of the SIRT3 gene, human silent information regulator Sir2 homologue, and survivorship in the elderly.

The human sirtuin 3 (SIRT3) gene encodes a putative mitochondrial NAD-dependent deacetylase (SIRT3) which belongs to the evolutionary conserved family of sirtuin 2 proteins. Studies in model organisms have demonstrated that SIR2 genes control lifespan, while no data are available regarding a possible role of SIRT3 in human longevity. By analysing the genotype-specific survival function relevant to the G477T marker of SIRT3, we found that in males the TT genotype increases (p=0.0272), while the GT genotype decreases (p=0.0391) survival in the elderly. Since SIRT3 lies in a chromosomal region (11p15.5) where four genes potentially associated with longevity are located (HRAS1, Insulin-like Growth Factor 2, Proinsulin, and Tyrosine Hydroxylase) we tested for linkage-disequilibrium between G477T alleles and alleles of the above genes. The disequilibrium was not significant in any case, thus suggesting that SIRT3 itself, or a gene strictly linked to SIRT3, may have a role in human longevity.

The allele (A)(-110) in the promoter region of the HSP70-1 gene is unfavorable to longevity in women.

Heat shock proteins (HSPs) are crucial for maintenance of cell homeostasis and survival both during and after various stresses. The capability to cope with stress is believed to affect the chance of health and survival at organismal level. We have investigated whether the gene pool relevant to the (A/C)(-110) polymorphism in the promoter region of the HSP70-1 gene changes as the population ages and survival selection occurs. A total of 591 southern Italian subjects were enrolled in the study (263 males and 328 females; age range 18-109 years), free of clinically manifest diseases and with normal haemato-chemical parameters. A significant age-related decrease of the frequency of allele (A)(-110) was observed in females. The probability ratio of 0.403 (95% confidence interval [0.163, 0.910]) computed by considering female centenarians as cases and young women (18-49 years old) as controls showed that the (A)(-110) allele is unfavorable to longevity in females.

[Lipoprotein glycation and glycoxidation: their importance in diabetes mellitus]. / La glicación y glicoxidación de las lipoproteínas. Su importancia en la diabetes mellitus.

Chronic hyperglycemia induces an increase in the non enzymatic glycation of circulating and structural proteins together with a glucose-generated oxidative and carbonyl stress, known as glycoxidation. The physicochemical characteristics and the metabolism of lipoproteins are altered by glycation/glycoxidation and resemble those of other body proteins, except for the fact that there is a simultaneous glycoxidation of both protein and phospholipid components generating an oxidative stress that increases lipoxidation. Information gathered during the last few years suggests that, among lipoproteins, modified LDL would principally contribute to developing diabetic micro-macrovascular complications. The control and the prevention of the progress of such complications are difficult to attain due to the irreversibility of glycoxidation. As glycation/glycoxidation is related to mean blood glucose, the goal in diabetes treatment must be the achievement of a close to normal metabolic control. This review summarizes advances in the importance of lipoprotein glycation/glycoxidation in diabetes mellitus.

La glicación y glicoxidación de las lipoproteínas. Su importancia en la diabetes mellitus. / [Lipoprotein glycation and glycoxidation: their importance in diabetes mellitus]

Chronic hyperglycemia induces an increase in the non enzymatic glycation of circulating and structural proteins together with a glucose-generated oxidative and carbonyl stress, known as glycoxidation. The physicochemical characteristics and the metabolism of lipoproteins are altered by glycation/glycoxidation and resemble those of other body proteins, except for the fact that there is a simultaneous glycoxidation of both protein and phospholipid components generating an oxidative stress that increases lipoxidation. Information gathered during the last few years suggests that, among lipoproteins, modified LDL would principally contribute to developing diabetic micro-macrovascular complications. The control and the prevention of the progress of such complications are difficult to attain due to the irreversibility of glycoxidation. As glycation/glycoxidation is related to mean blood glucose, the goal in diabetes treatment must be the achievement of a close to normal metabolic control. This review summarizes advances in the importance of lipoprotein glycation/glycoxidation in diabetes mellitus.

Niveles de fructosamina en embarazadas con distinta edad de gestación y niños de primera y segunda infancia / Fructosamine levels in pregnant women at different gestational stages and in children of first and second infancy

El objetivo de este estudio fue establecer en nuestra población valores de referencia para fructosamina en embarazadas normales durante el primero, segundo y tercer trimestre de gestación y en niños de primera (<1-6 años) y segunda (6-12) infancia. El límite superior de fructosamina (expresado como 97,5 percentilo) para adultos de nuestro medio (271 Amol/L) no difiere del hallado en estudios multicéntricos. En cambio son menores los límites de normalidad para embarazadas de segundo (231 Amo/L) y tercer (221 Amol/L) trimestre de embarazo, y niños de primera infancia (239 Amol/L). Lo mismo ocurre al expresar los valores normalizados por proteinemia. Exiten correlaciones inversas significativasentre la concentración de fructosamina y a) el progreso de la edad de gestación(r=0,64; p<0,001; n= 147), y b) el incremento de la edad en los niños de 0 a 12 años (r=0,63; p<0,001; n= 137). Estos resultados demuestran la necesidad de definir rangos de normalidad independientes para los adultos, los niños de primera infancia y las embarazadas de acuerdo a su edad de gestación (AU)

Niveles de fructosamina en embarazadas con distinta edad de gestación y niños de primera y segunda infancia / Fructosamine levels in pregnant women at different gestational stages and in children of first and second infancy

El objetivo de este estudio fue establecer en nuestra población valores de referencia para fructosamina en embarazadas normales durante el primero, segundo y tercer trimestre de gestación y en niños de primera (<1-6 años) y segunda (6-12) infancia. El límite superior de fructosamina (expresado como 97,5 percentilo) para adultos de nuestro medio (271 µmol/L) no difiere del hallado en estudios multicéntricos. En cambio son menores los límites de normalidad para embarazadas de segundo (231 µmo/L) y tercer (221 µmol/L) trimestre de embarazo, y niños de primera infancia (239 µmol/L). Lo mismo ocurre al expresar los valores normalizados por proteinemia. Exiten correlaciones inversas significativasentre la concentración de fructosamina y a) el progreso de la edad de gestación(r=0,64; p<0,001; n= 147), y b) el incremento de la edad en los niños de 0 a 12 años (r=0,63; p<0,001; n= 137). Estos resultados demuestran la necesidad de definir rangos de normalidad independientes para los adultos, los niños de primera infancia y las embarazadas de acuerdo a su edad de gestación