Davide Castaldi

Role of epigenetics in human aging and longevity: genome-wide DNA methylation profile in centenarians and centenarians' offspring.

The role of epigenetics in the modulation of longevity has not been studied in humans. To this aim, (1) we evaluated the DNA methylation from peripheral leukocytes of 21 female centenarians, their 21 female offspring, 21 offspring of both non-long-lived parents, and 21 young women through ELISA assay, pyrosequencing analysis of Alu sequences, and quantification of methylation in CpG repeats outside CpG islands; (2) we compared the DNA methylation profiles of these populations through Infinium array for genome-wide CpG methylation analysis. We observed an age-related decrease in global DNA methylation and a delay of this process in centenarians’ offspring. Interestingly, literature data suggest a link between the loss of DNA methylation observed during aging and the development of age-associated diseases. Genome-wide methylation analysis evidenced DNA methylation profiles specific for aging and longevity: (1) aging-associated DNA hypermethylation occurs predominantly in genes involved in the development of anatomical structures, organs, and multicellular organisms and in the regulation of transcription; (2) genes involved in nucleotide biosynthesis, metabolism, and control of signal transmission are differently methylated between centenarians’ offspring and offspring of both non-long-lived parents, hypothesizing a role for these genes in human longevity. Our results suggest that a better preservation of DNA methylation status, a slower cell growing/metabolism, and a better control in signal transmission through epigenetic mechanisms may be involved in the process of human longevity. These data fit well with the observations related to the beneficial effects of mild hypothyroidism and insulin-like growth factor I system impairment on the modulation of human lifespan.

Age-dependent skewing of X chromosome inactivation appears delayed in centenarians' offspring. Is there a role for allelic imbalance in healthy aging and longevity?

Recently, it has been proposed that age‐related X chromosome inactivation (XCI) skewing can clinically result in late‐onset X‐linked disorders. This observation leads to hypothesize that age‐related skewed XCI might also influence lifespan in women. To investigate this issue, we employed a new experimental model of longevity and healthy aging including 55 female centenarians, 40 of their offspring, 33 age‐matched offspring of both non‐long‐lived parents and 41 young women. Peripheral blood DNA from 169 females was screened for heterozygosity at the HUMARA locus. We confirmed that skewing of XCI is an age‐dependent phenomenon. However, skewed XCI was significantly less severe and frequent in centenarians’ offspring [degree of skewing (DS) = 0.16 ± 0.02] compared to age‐matched offspring of both non‐long‐lived parents (DS = 0.24 ± 0.02) (P < 0.05). A second goal was to assess whether changes in XCI pattern could be a consequence of loss of methylation on X chromosome. Using a methylation array evaluating 1085 CpG sites across X chromosome and eleven CpG sites located at HUMARA locus, no differences in methylation levels and profiles emerged between all groups analysed, thus suggesting that age‐associated epigenetic changes could not influence HUMARA results. In conclusion, the results presented herein highlight for the first time an interesting link between skewing of XCI and healthy aging and longevity. We speculate that the allelic imbalance produced by XCI skewing may compromise the cooperative and compensatory organization occurring between the two cell populations that make up the female mosaic.

Variations of the angiotensin II type 1 receptor gene are associated with extreme human longevity

Longevity phenotype in humans results from the influence of environmental and genetic factors. Few gene polymorphisms have been identified so far with a modest effect on lifespan leaving room for the search of other players in the longevity game. It has been recently demonstrated that targeted disruption of the mouse homolog of the human angiotensin II type 1 receptor (AT1R) gene (AGTR1) translates into marked prolongation of animal lifespan (Benigni et al., J Clin Invest 119(3):524–530, 2009). Based on the above study in mice, here we sought to search for AGTR1 variations associated to reduced AT1 receptor protein levels and to prolonged lifespan in humans. AGTR1 was sequenced in 173 Italian centenarians and 376 younger controls. A novel non-synonymous mutation was detected in a centenarian. Two polymorphisms in AGTR1 promoter, rs422858 and rs275653, in complete linkage disequilibrium, were significantly associated with the ability to attain extreme old age. We then replicated the study of rs275653 in a large independent cohort of Japanese origin (598 centenarians and semi-supercentenarians, 422 younger controls) and indeed confirmed its association with exceptional old age. In combined analyses, rs275653 was associated to extreme longevity either at recessive model (P = 0.007, odds ratio (OR) 3.57) or at genotype level (P = 0.015). Significance was maintained after correcting for confounding factors. Fluorescence activated cell sorting analysis revealed that subjects homozygous for the minor allele of rs275653 had less AT1R-positive peripheral blood polymorphonuclear cells. Moreover, rs275653 was associated to lower blood pressure in centenarians. These findings highlight the role of AGTR1 as a possible candidate among longevity-enabling genes.

Hemostasis and ageing

On March 19, 2008 a Symposium on Pathophysiology of Ageing and Age-Related Diseases was held in Palermo, Italy. The lecture of D. Mari on Hemostasis and ageing is summarized herein. Physiological ageing is associated with increased plasma levels of many proteins of blood coagulation together with fibrinolysis impairment. This may be of great concern in view of the known association between vascular and thromboembolic diseases and ageing. On the other hand, centenarians are characterized by a state of hypercoagulability and possession of several high-risk alleles and well-known atherothrombotic risk markers but this appears to be compatible with longevity and/or health. Parameters considered risk factors for atherosclerotic vascular diseases in young people may lose their biological significance in advanced age and assume a different role.

Limited utility of ITPA deficiency to predict early anemia in HCV patients with advanced fibrosis receiving Telaprevir.

Background Severe anemia is a common side effect of Pegylated Interferon + Ribavirin (PR) and Telaprevir (TVR) in hepatitis C virus (HCV) genotype 1 patients with advanced fibrosis or cirrhosis (F3–F4). Inosine triphosphatase (ITPA) genetic variants are associated with RBV- induced anemia and dose reduction. Aim To test the association of ITPA polymorphisms rs1127354 and rs7270101 with hemoglobin (Hb) decline, need for RBV dose reduction (RBV DR), erythropoietin (EPO) support and blood transfusions during the first 12 weeks of TVR triple therapy. Materials and Methods 69 consecutive HCV-1 patients (mean age 57 years) with F3-F4 who received PR and TVR were genotyped for ITPA polymorphisms rs1127354 and rs7270101. Estimated ITPA deficiency was graded on severity (0–3, no deficiency/mild/moderate/severe). Results ITPA deficiency was absent in 48 patients (70%), mild in 12 (17%) and moderate in 9 patients (13%). Mean week 4 Hb decline was higher in non ITPA deficient patients (3,85 g/dL) than in mildly or moderately ITPA deficient patients (3,07 g/dL and 1,67 g/dL, p<0.0001). Grade 3–4 anemia developed in 81% non ITPA deficient patients versus 67% mild deficient and 55% moderate deficient patients (p = ns). Grade of ITPA deficiency was not associated with RbvDR (no deficiency: 60%, mild: 58%, moderate: 67%; p = ns), EPO use (no deficiency: 65%, mild: 58%, moderate:56%; p = ns) or need for blood transfusion (no deficiency: 27%, mild: 17%, moderate: 33%; p = ns). Conclusions In patients with F3–F4 chronic hepatitis C receiving TVR based therapy, ITPA genotype does not impact on the management of early anemia.

An Efficient Implementation of Geometric Semantic Genetic Programming for Anticoagulation Level Prediction in Pharmacogenetics

The purpose of this study is to develop an innovative system for Coumarin-derived drug dosing, suitable for elderly patients. Recent research highlights that the pharmacological response of the patient is often affected by many exogenous factors other than the dosage prescribed and these factors could form a very complex relationship with the drug dosage. For this reason, new powerful computational tools are needed for approaching this problem. The system we propose is called Geometric Semantic Genetic Programming, and it is based on the use of recently defined geometric semantic genetic operators. In this paper, we present a new implementation of this Genetic Programming system, that allow us to use it for real-life applications in an efficient way, something that was impossible using the original definition. Experimental results show the suitability of the proposed system for managing anticoagulation therapy. In particular, results obtained with Geometric Semantic Genetic Programming are significantly better than the ones produced by standard Genetic Programming both on training and on out-of-sample test data.

Plasminogen activator inhibitor-1 4G/5G polymorphism and susceptibility to endometriosis in the Italian population.

OBJECTIVES Some controversy exists for the potential association of the plasminogen activator inhibitor-1 (PAI-1) gene polymorphism 4G/5G and susceptibility to endometriosis. To clarify this issue, we have examined the prevalence of this polymorphism in a case-control study in the Italian population. STUDY DESIGN The PAI-1 4G/5G polymorphism was evaluated in n=368 reproductive year aged Caucasian women who underwent gynaecological laparoscopy for chronic pelvic pain, infertility, ovarian cysts and myomas. A second group of controls included n=329 normal subjects. RESULTS The 697 women enrolled were divided as follows: the endometriosis group (n=204), the gynaecological control group (n=164) and the general population control group (n=329). No statistical significant differences emerged between endometriosis patients and gynaecological controls with regard to the allele frequencies and co-dominant and dominant models of genotype distribution. A borderline statistical difference was only observed for the recessive model of inheritance in which, contrary to previous findings, the PAI-1 4G/4G genotype seems to be less linked to the disease development. CONCLUSION The findings reported herein do not support the previously reported data indicating a greater susceptibility to endometriosis in patients harbouring the PAI-1 4G/5G and 4G/4G genotypes and exclude a significant role of polymorphism in endometriosis development.

Common adipokine features of neonates and centenarians

Abstract Adipose tissue seems to be a pivotal organ in the aging process. We investigated whether healthy aging could have its roots in a sound metabolic condition from the first year of life by evaluating leptin and adiponectin levels in neonates [33 adequate for gestational age (AGA) and 29 small for gestational age (SGA)], 48 centenarians, and 50 healthy elderly subjects. At birth, SGA neonates showed lower leptin levels (SGA 0.88±0.28; AGA 2.22±0.91 ng/mL; p<0.05) and comparable adiponectin levels with respect to AGA. At 1 year, SGA showed increased leptin (SGA 1.74±0.28; AGA 1.31±0.19 ng/mL) and slightly reduced adiponectin concentrations (SGA 35.51±2.53; AGA 38.56±3.18 μg/mL) than AGA. Centenarians showed lower leptin (centenarians 18.71±3.78; elderly 34.81±7.27 ng/mL; p<0.05) and higher adiponectin levels (centenarians 55.63±7.7; elderly 33.51±4.1 μg/mL; p<0.05) than elderly subjects. Centenarians, like AGA infants during the first year of life, show a favorable adipokine profile, suggesting that the metabolic condition at early age could affect the longevity of an individual.

An efficient implementation of geometric semantic genetic programming for anticoagulation level prediction in pharmacogenetics

In the last few years researchers have dedicated several efforts to the definition of Genetic Programming (GP) [?] systems based on the semantics of the solutions, where by semantics we generally intend the behavior of a program once it is executed on a set of inputs, or more particularly the set of its output values on input training data (this definition has been used, among many others, for instance in [?, ?, ?, ?]). In particular, new genetic operators, called geometric semantic operators, have been proposed by Moraglio et al. [?]. They are defined s follows: