Biomedical subjects

M Bonafè

Publications and source records attributed to M Bonafè.

At least 19 recordsLinked to original sources

PubMed2005

p66(shc) is highly expressed in fibroblasts from centenarians.

p66(shc-/-) mice exhibit prolonged lifespan and increased resistance to oxidative and hypoxic stress. To investigate p66(shc) involvement in human longevity, p66(shc) mRNA and protein were evaluated in fibroblasts from young people, elderly and centenarians, exposed to oxidative or hypoxic stress. Unexpectedly, centenarians showed the highest basal levels of p66(shc). Oxidative stress induced p66(shc) in all samples. At variance, hypoxic stress caused p66(shc) reduction only in cells from centenarians. These changes occurred in absence of any modification of p66(shc) promoter methylation pattern. Intriguingly, in cells from centenarians, p66(shc) induction was affected by p53 codon 72 polymorphism. Thus, cells from centenarians present a peculiar regulation of p66(shc), suggesting that its role in mammalian longevity is more complex than previously thought.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Apoptosis-resistant phenotype in HL-60-derived cells HCW-2 is related to changes in expression of stress-induced proteins that impact on redox status and mitochondrial metabolism.

The onset of resistance to drug-induced apoptosis of tumour cells is a major problem in cancer therapy. We studied a drug-selected clone of promyelocytic HL-60 cells, called HCW-2, which display a complex resistance to a wide variety of apoptosis-inducing agents and we found that these cells show a dramatic increase in the expression of heat shock proteins (Hsps) 70 and 27, while the parental cell line does not. It is known that stress proteins such as Hsps can confer resistance to a variety of damaging agents other than heat shock, such as TNF-alpha, monocyte-induced cytotoxicity, and also play a role in resistance to chemotherapy. This elevated expression of Hsps is paralleled by an increased activity of mitochondrial metabolism and pentose phosphate pathway, this latter leading to high levels of glucose-6-phosphate dehydrogenase and, consequently, of glutathione. Thus, the apoptotic-deficient phenotype is likely because of the presence of high levels of stress response proteins and GSH, which may confer resistance to apoptotic agents, including chemotherapy drugs. Moreover, the fact that in HCW-2 cells Hsp70 are mainly localised in mitochondria may account for the increased performances of mitochondrial metabolism. These observations could have some implications for the therapy of cancer, and for the design of combined strategies that act on antioxidant defences of the neoplastic cell.

Apoptosis↗

PubMed2003

Centenarians as a model for healthy aging.

For over 10 years we have studied centenarians as a model to address the biological basis of aging and longevity, with particular attention to immunology and genetics. The most important findings can be summarized as follows. (i) Human immunosenescence represents a complex remodelling, whereby clonotypical immunity deteriorates, while ancestral, innate immunity is largely preserved. (ii) Continuous exposure to antigens causes a lifelong, chronic antigenic stress, which is responsible, together with the involution of the thymus, for the accumulation of memory/effector T cells and the exhaustion of naïve T cells. (iii) Aging is characterized by a peculiar chronic inflammatory status that we propose to call 'inflammaging', which appears to be under genetic control, is detrimental for longevity and is more evident in men than in women. Inflammaging, i.e. the up-regulation of a variety of anti-stress responses at the cellular and molecular level, is the consequence of the ability of the body to adapt to and counteract the effects of a variety of stressors, which causes the accumulation of molecular and cellular scars. Inflammaging is considered the common and most important driving force of age-related pathologies, such as neurodegeneration, atherosclerosis, diabetes and sarcopenia, among others, all of which share an inflammatory pathogenesis. (iv) Possible strategies to counteract the major effects of immunosenescence and inflammaging, such as the systematic reduction of the lifelong antigenic load, the elimination of chronic infections, thymic rejuvenation and preventative treatment with anti-inflammatory drugs in people with a pro-inflammatory genotype, are envisaged.

Aged↗

PubMed2002

Gender-specific association between -1082 IL-10 promoter polymorphism and longevity.

Ageing is characterized by a pro-inflammatory status, which could contribute to the onset of major age-related diseases. Thus, genetic variations in pro- or anti-inflammatory cytokines might influence successful ageing and longevity. IL-10 is an appropriate candidate because it exerts powerful inhibitory effects on pro-inflammatory function. IL-10 production is controlled by several polymorphic elements in the 5' flanking region of IL-10 gene on 1q32 locus, involving alleles at two microsatellite regions and several polymorphisms in promoter region. We analysed in 190 Italian centenarians (>99 years old, 159 women and 31 men) and in 260 <60 years old control subjects (99 women and 161 men), matched for geographical distribution, genotype frequencies for -1082G-->A, -819C-->T and -592C-->A IL-10 proximal promoter gene biallelic polymorphisms by sequence specific probes. -1082G homozygous genotype was increased in centenarian men (P < 0.025) but not in centenarian women. No difference was found between centenarians and control subjects regarding the other two polymorphisms. The presence of -1082GG genotype, suggested to be associated with high IL-10 production, significantly increases the possibility to reach the extreme limit of human lifespan in men. Together with previous data on other polymorphic loci (Tyrosine Hydroxylase, mitochondrial DNA, IL-6, haemochromatosis, IFN-gamma), this finding points out that that gender is a major variable in the genetics of longevity, suggesting that men and women follow different strategies to reach longevity. Concerning the biological significance of this association, we have not searched for functional proves that IL-10 is involved. Thus, we should conclude that our data only suggest that a marker on 1q32 genomic region may be involved in successful ageing in man. However, recent data on IL-6 and IFN-gamma genes suggest that longevity is negatively associated with genotypes coding for a pro-inflammatory profile. Thus, it is intriguing that the possession of -1082G genotype, suggested to be associated with IL-10 high production, is significantly increased in centenarians.

Aged↗

PubMed2001

A stochastic model for CD8(+)T cell dynamics in human immunosenescence: implications for survival and longevity.

We propose here a stochastic model for the CD 8(+)T lymphocyte dynamics on the long time-scale of the human lifespan. Our purpose has been to test the hypothesis, recently proposed on the basis of our experimental data (Fagnoni et al., 2000), that the depletion of virgin CD8(+)T lymphocytes can be considered a reliable biomarker related to the risk of death. This hypothesis is embedded in a more general theory of immunosenescence according to which the accumulation of antigen experienced (AE) T cells and the concomitant exhaustion of antigen non-experienced (ANE) T cells with age, mostly due to the chronic lifelong exposure to antigens, is a major characteristic of the remodeling of the human immune system with age. In our model we considered a deterministic balance of ANE and AE T cell concentrations plus a stochastic forcing, which describes the chronic antigenic stress fluctuations, assuming a mean genetically determined capability of individuals to respond to antigens. The major results of our model is the validation of the above-mentioned hypothesis, since the model is capable of fitting the experimental data concerning the changes of ANE T cell concentration over age, and at the same time to reproduce survival curves similar to the demographic ones. Furthermore, the stochastic process results in being responsible for the peculiar shape of the survival curves.

Aging↗

PubMed2001

Recent advances in human gene-longevity association studies.

This paper reviews the recent literature on genes and longevity. The influence of genes on human life span has been confirmed in studies of life span correlation between related individuals based on family and twin data. Results from major twin studies indicate that approximately 25% of the variation in life span is genetically determined. Taking advantage of recent developments in molecular biology, researchers are now searching for candidate genes that might have an influence on life span. The data on unrelated individuals emerging from an ever-increasing number of centenarian studies makes this possible. This paper summarizes the rich literature dealing with the various aspects of the influence of genes on individual survival. Common phenomena affecting the development of disease and longevity are discussed. The major methodological difficulty one is confronted with when studying the epidemiology of longevity involves the complexity of the phenomenon, which arises from the polygenic nature of life span and historical mortality change. We discuss this issue and suggest new methodological approaches.

Humans↗

PubMed2001

Immunogenetics of longevity. Is major histocompatibility complex polymorphism relevant to the control of human longevity? A review of literature data.

Literature data suggest that human longevity may be directly correlated with optimal functioning of the immune system. Therefore, it is likely that one of the genetic determinants of longevity resides in those polymorphisms for the immune system genes that regulate immune responses. Accordingly, studies performed on mice have suggested that the Major Histocompatibility Complex (MHC), known to control a variety of immune functions, is associated with the life span of the strains. In the last 25 years, a fair number of cross-sectional studies that searched for the role of HLA (the human MHC) genes on human longevity by comparing HLA antigen frequencies between groups of young and elderly persons have been published, but conflicting findings have been obtained. In fact, the same HLA antigens are increased in some studies, decreased in others and unchanged in others. On the whole, that could lead us to hypothesize that the observed age-related differences in the frequency of HLA antigens are due to bias. In our opinion, this hypothesis is real for most studies owing to major methodological problems. However, some studies that do not meet these biases have shown an association between longevity and some HLA-DR alleles or HLA-B8,DR3 haplotype, known to be involved in the antigen non-specific control of immune response. Thus, HLA studies in man may be interpreted to support suggestions derived from the studies on congenic mice on MHC effects on longevity. However, in mice the association may be by way of susceptibility to lymphomas whereas, in human beings, the effect on longevity is likely, via infectious disease susceptibility. Longevity is associated with positive or negative selection of alleles (or haplotypes) that respectively confer resistance or susceptibility to disease(s), via peptide presentation or via antigen non-specific control of the immune response.

Aging↗

PubMed2001

Mitochondria, aging and longevity--a new perspective.

A new perspective is emerging indicating that mitochondria play a critical role in aging not only because they are the major source and the most proximal target of reactive oxygen species, but also because they regulate stress response and apoptosis. Recent literature indicates that, in response to stress, a variety of molecules translocate to and localise in mitochondria. These molecules are likely to interact with each other, in order to mediate mitochondria/nucleus cross-talk and to regulate apoptosis. We surmise that an integration of signals in multimolecular complexes occurs at mitochondrial level. These phenomena can be of critical importance for human aging and longevity.

Aging↗

PubMed2001

Polymorphisms of drug-metabolizing enzymes in healthy nonagenarians and centenarians: difference at GSTT1 locus.

Drug metabolizing enzymes are involved in the detoxification of several drugs, environmental substances, and carcinogenic compounds, and their polymorphisms have been associated with risk for a variety of cancer. In this paper, we compared the frequency of polymorphisms in cytochrome P450-1A1 gene (CYP1A1), a phase 1 gene (oxidation, activation), and of two polymorphisms of glutathione S-transferase enzymes (GSTM1, GSTT1), two phase 2 genes (conjugation, detoxification). Two groups were studied and compared, i.e., 94 nonagenarians and centenarians and 418 control subjects of younger age. A significant difference in the proportion of nonagenarians and centenarians homozygotes for a GSTT1 deletion (28%) was observed in comparison to control subjects (19%, P = 0.03). The distribution of the other gene polymorphisms did not differ in the two groups. These findings on phase 2 drug-metabolizing enzyme gene polymorphisms may help in disentangling gene-environmental interactions which can have a role in successful aging and longevity, as well as in cancer incidence in the oldest old.

Adolescent↗

PubMed2001

A gender--dependent genetic predisposition to produce high levels of IL-6 is detrimental for longevity.

Current literature indicates that elevated IL-6 serum levels are associated with diseases, disability and mortality in the elderly. In this paper, we studied the IL-6 promoter genetic variability at -174 C/G locus and its effect on IL-6 serum levels in a total of 700 people from 60 to 110 years of age, including 323 centenarians. We found that the proportion of homozygotes for the G allele at -174 locus decreases in centenarian males, but not in centenarian females. Moreover, we found that, only among males, homozygotes for the G allele at -174 locus have higher IL-6 serum levels in comparison with carriers of the C allele. On the whole, our data suggest that those individuals who are genetically predisposed to produce high levels of IL-6 during aging, i.e. -174 locus GG homozygous men, are disadvantaged for longevity.

Aged↗

PubMed2001

Neuroinflammation and the genetics of Alzheimer's disease: the search for a pro-inflammatory phenotype.

The role of interleukin 1 (IL-1) and interleukin 6 (IL-6) in the pathogenesis of Alzheimer's disease (AD) is reviewed within the framework of "inflamm-aging", i.e., the characteristic chronic pro-inflammatory status which develops in old age, and neuroinflammation, i.e., the peculiar inflammatory process which is present in the brain of AD patients. In particular, the data suggesting that several IL-1 and IL-6 gene polymorphisms can contribute to the risk of developing AD are reviewed. The possibility as well as the difficulty in identifying a pro-inflammatory phenotype, and its importance for the prevention, diagnosis and therapy of AD and other age-related pathologies are discussed.

Aged↗

PubMed2001

Mitochondrial DNA haplogroups and APOE4 allele are non-independent variables in sporadic Alzheimer's disease.

Allele epsilon4 of the nuclear APOE gene is a leading genetic risk factor for sporadic Alzheimer's disease (AD). Moreover, an allele-specific effect of APOE isoforms on neuronal cell oxidative death is known. Because of the role of the mitochondrial genome (mtDNA) in oxidative phosphorylation and oxidative stress, an interaction between APOE polymorphism and mtDNA inherited variability in the genetic susceptibility to sporadic AD can be hypothesized. We have explored this hypothesis by analyzing mtDNA germline variants (mtDNA haplogroups) in a sample of AD patients (213 subjects) genotyped for APOE and classified as APOE epsilon4 carriers and non-carriers. We found that the frequency distribution of mtDNA haplogroups is different between epsilon4 carriers and non-carriers (P=0.018), thus showing non-random association between APOE and mtDNA polymorphisms. The same analysis, carried out in two samples of healthy subjects (179 age-matched and 210 individuals aged more than 100 years), showed independence between epsilon4 allele and mtDNA haplogroups. Therefore, the APOE/mtDNA interaction is restricted to AD and may affect susceptibility to the disease. In particular, some mtDNA haplogroups (K and U) seem to neutralize the harmful effect of the APOE epsilon4 allele, lowering the epsilon4 odds ratio from statistically significant to non-significant values.

Aged↗

PubMed2001

Increase of homozygosity in centenarians revealed by a new inter-Alu PCR technique.

In the present study a novel inter-Alu PCR technique that allows one to detect inter-individual differences in the genomic regions flanked by Alu repetitive sequences was developed. Two primers complementary to sequences present in different Alu repeats and marked with two different fluorochromes were used in the same PCR reaction, and the PCR products were separated and analyzed by capillary electrophoresis using an automatic sequencer. The method is highly reliable, and three patterns of peaks (QM376-400, QM780-790 and QM480) appeared to be representative for germ-line polymorphisms, as suggested by the results obtained in nine couples of monozygotic twins and four three-generation families. The frequency of these polymorphic peaks was studied in two different age groups (100 young subjects and 69 centenarians). In two out of the three regions (QM376-400 and QM480) a significant increase in homozygote genotypes frequency was observed in centenarians. These counterintuitive results suggest that increased homozygosity contributes to human longevity. This novel inter-Alu PCR approach could represent a valuable tool to identify longevity-associated DNA sequences interspersed throughout human genome, without making any a priori assumption about their nature and function.

Aged↗

PubMed2001

Sex-specific longevity associations defined by Tyrosine Hydroxylase-Insulin-Insulin Growth Factor 2 haplotypes on the 11p15.5 chromosomal region.

By studies in centenarians, it was recently found that an STR marker of the Tyrosine Hydroxylase (TH, 11p15.5) gene is associated with human longevity. The aim of the present study was to continue the exploration of the 11p15.5 chromosomal region in human longevity by analyzing two additional RFLP markers, which lie in the Insulin (INS) and Insulin Growth Factor 2 (IGF2) genes. Both the genes, which are localized downstream TH, are indeed good candidates in longevity, as ascertained on the basis of laboratory studies in experimental models. Neither INS nor IGF2 markers did reveal association with longevity. Nevertheless, linkage disequilibrium analyses showed sex-specific longevity associations defined by both TH-INS and TH-IGF2 haplotypes. On the whole, the results reinforce the involvement of the chromosomal region spanning from TH to IGF2 loci in controlling the longevity phenotype in humans.

Adult↗

PubMed2001

Low insulin resistance and preserved beta-cell function contribute to human longevity but are not associated with TH-INS genes.

Tyrosine Hydroxylase (TH) and Insulin (INS) genes lie extremely close in the 11p15.5 chromosomal region. An STR marker of the TH gene had revealed this locus associated with longevity. Thus, it seemed of interest to investigate the association between the TH-STR and INS gene variability (FokI-RFLP) with a phenotypic trait, such as the degree of insulin resistance (IR) and beta-cell function in centenarians (C). We analyzed age-related trajectories of IR and beta-cell function in a large sample (n=466) of individuals whose age ranged from 28 to more than 100 years; furthermore, allele average effects on IR and beta-cell function relevant to TH-STR and INS-FokI polymorphisms were estimated in C. Both IR and beta-cell function increased with advancing age and declined in subjects older than 90 years (p for trend <0.001). C had lower IR (1.5+/-0.7 vs. 3.9+/-1.7, p<0.001) and beta-cell function (26.1+/-8.5 vs. 55.4+/-16, p<0.001) than nC. In nC, but not in C, IR and beta-cell function correlated with the main anthropometric and metabolic confounders. Nevertheless, significant allele average effects by TH-STR and INS-FokI polymorphisms on IR and beta-cell function were not observed in C. In conclusion, C has a lower degree of IR and a preserved beta-cell function in comparison to nC, but the cause of such metabolic differences, which are likely does not lie in this genomic region.

Adult↗

PubMed2001

The unexpected contribution of immunosenescence to the leveling off of cancer incidence and mortality in the oldest old.

In this paper the hypothesis that some features of immunosenescence might impact on the levelling off of cancer incidence and mortality in the oldest old will be considered. In fact, the term immunosenescence suggests that a progressive loss of immune system (IS) function occurs with aging. However, the age-related modifications of the IS can be more properly acknowledged as a 'remodeling' characterized by profound structural changes, which modify the functional properties of IS. We suggest that the expansion with age of natural killer cells (NK) and of T cells which progressively acquire phenotypes intermediate between T lymphocytes and NK cells, together with the age-related changes in the production of inflammatory/anti-inflammatory cytokines, such as INFgamma and IL-4, might create an environment unfavorable for neoplastic growth in the oldest old. In this perspective, studies on immunosenescence likely provide insights on mechanisms responsible for the individual capacity to escape from the life-threatening consequences of cancer outgrowth.

Aged↗

PubMed2001

Replication studies in longevity: puzzling findings in Danish centenarians at the 3'APOB-VNTR locus.

In Danes we replicated the 3'APOB-VNTR gene/longevity association study previously carried out in Italians, by which the Small alleles (less than 35 repeats) had been identified as frailty alleles for longevity. In Danes, neither genotype nor allele frequencies differed between centenarians and 20-64-year-old subjects. However, when Danish and Italian data were compared, a significant difference (p = 0.0004) was found between the frequencies of Small alleles in youths, which disappeared in centenarians (p = 0.290). Furthermore, the demographic-genetic approach revealed in Danes a significant gene-sex interaction relevant to Long alleles (more than 37 repeats). The different findings in Denmark and Italy suggest that gene/longevity associations are population-specific, and heavily affected by the population-specific genetic and environmental history.

Adult↗

PubMed2001

Paradoxes in longevity: sequence analysis of mtDNA haplogroup J in centenarians.

Previous studies have shown that mitochondrial DNA (mtDNA) haplogroup J is significantly over-represented in healthy centenarians with respect to younger controls, thus suggesting that this haplogroup predisposes to successful aging and longevity. On the other hand, the same haplogroup is reported to have elevated frequency in some complex diseases. To verify if centenarians clustered in a particular lineage within J we have sequenced the D-loop region from 18 centenarians and 18 younger controls, previously characterized to be J. Then the entire mtDNA molecule was sequenced in a sub-sample of nine centenarians to find possible functional mutations associated with haplogroup J in successful aging. No clustering of the J haplogroup mtDNA from centenarians was observed. In addition, most of the mutations found are known as disease-associated mutations. The general picture that emerges from the study is that the J haplogroup of centenarians is surprisingly similar to that found in complex diseases, as well as in Leber Hereditary Optic Neuropathy. This finding implies that the same mutations could predispose to disease or longevity, probably according to individual-specific genetic backgrounds and stochastic events. This data reveals another paradox of centenarians and confirms the complexity of the longevity trait.

Aged↗