Maria Paola Grimaldi

Inflammatory networks in ageing, age-related diseases and longevity.

Inflammation is considered a response set by the tissues in response to injury elicited by trauma or infection. It is a complex network of molecular and cellular interactions that facilitates a return to physiological homeostasis and tissue repair. The individual response against infection and trauma is also determined by gene variability. Ageing is accompanied by chronic low-grade inflammation state clearly showed by 2-4-fold increase in serum levels of inflammatory mediators. A wide range of factors has been claimed to contribute to this state; however, the most important role seems to be played by the chronic antigenic stress, which affects immune system thorough out life with a progressive activation of macrophages and related cells. This pro-inflammatory status, interacting with the genetic background, potentially triggers the onset of age-related inflammatory diseases as atherosclerosis. Thus, the analysis of polymorphisms of the genes that are key nodes of the natural immunity response might clarify the patho-physiology of age-related inflammatory diseases as atherosclerosis. On the other hand, centenarians are characterized by marked delay or escape from age-associated diseases that, on average, cause mortality at earlier ages. In addition, centenarian offspring have increased likelihood of surviving to 100 years and show a reduced prevalence of age-associated diseases, as cardiovascular disease (CVD) and less prevalence of cardiovascular risk factors. So, genes involved in CVD may play an opposite role in human longevity. Thus, the model of centenarians can be used to understand the role of these genes in successful and unsuccessful ageing. Accordingly, we report the results of several studies in which the frequencies of pro-inflammatory alleles were significantly higher in patients affected by infarction and lower in centenarians whereas age-related controls displayed intermediate values. These findings point to a strong relationship between the genetics of inflammation, successful ageing and the control of cardiovascular disease at least in men, in which these studies were performed. These data are also briefly discussed in the light of antagonistic pleiotropy theory and in order to pursuit a pharmacogenomics approach.

Inflammation, longevity, and cardiovascular diseases: role of polymorphisms of TLR4.

Abstract:  The total burden of infection at various sites may affect the progression of atherosclerosis, the risk being modulated by host genotype. The role of lipopolysaccaride receptor TLR4 is paradigmatic. It initiates the innate immune response against gram‐negative bacteria; and TLR4 polymorphisms, as ASP299GLY, suggested to attenuate receptor signaling, have been described. We demonstrated that TLR4 ASP299GLY polymorphism shows a significantly lower frequency in patients affected by myocardial infarction compared to controls, whereas centenarians show a higher frequency. Thus, people genetically predisposed to developing weak inflammatory activity, seem to have fewer chances of developing cardiovascular diseases (CVD) and, subsequently, live longer if they do not become affected by serious infectious diseases. These results are in agreement with our other data demonstrating how genetic background may exert the opposite effect with respect to inflammatory components in CVD and longevity. In the present report, to validate this hypothesis, the levels of interleukin (IL)‐6, a pro‐inflammatory cytokine involved in atherosclerosis and longevity, were determined by an enzyme‐linked immuno‐sorbent assay (ELISA) in supernatants from a whole blood assay after stimulation with subliminal doses of lipopolysaccaride (LPS) from Escherichia coli (E. coli). The samples, genotyped for the ASP299GLY polymorphism, were challenged with LPS for 4, 24, and 48 h. What we found was that Il‐6 values were significantly lower in carriers bearing TLR4 mutation. Therefore, the pathogen burden, by interacting with host genotype, determines the type and intensity of the immune‐inflammatory responses accountable for pro‐inflammatory status, CVD, and unsuccessful aging. On the other hand, our present data seem to explain the inconclusive results obtained in case–control studies taking into account the role of functional IL‐6 polymorphisms in successful and unsuccessful aging. In fact, IL6 levels seem to depend, in addition, on IL‐6 polymorphisms and on innate immunity gene polymorphisms as well.

Role of the pyrin M694V (A2080G) allele in acute myocardial infarction and longevity: a study in the Sicilian population

A proinflammatory genotype seems to contribute significantly to the risk of developing coronary heart disease (CHD). Conversely, the susceptibility alleles to inflammatory disease should be infrequent in the genetic background favoring longevity. In fact, in a modern environment, attainment of longevity is facilitated by an anti‐inflammatory status. To evaluate whether inflammatory alleles of pyrin, the gene responsible for familial Mediterranean fever (FMF) may play an opposite role in CHD and in longevity, we examined three FMF‐associated mutations, M694V (A2080G), M694I (G2082A), and V726A (T2177C), encoded by the FMF gene (MEFV) in 121 patients affected by acute myocardial infarction (AMI), in 68 centenarians, and in 196 age‐matched controls from Sicily. None of the Sicilian subjects studied carried the V726A and the M694I FMF‐related mutations. The proinflammatory M694V (A2080G) mutation was the only one we found, which was over‐represented significantly in CHD patients and under‐represented in oldest old, and intermediate values were in healthy, young controls. After adjustment for well‐recognized AMI risk factors, the M694V allele still predicted a significant risk to develop AMI. So, according to these results, we suggest that carrying the proinflammatory M694V pyrin allele may increase the risk to develop AMI. Conversely, the wild‐type pyrin genotype may predispose to a greater chance to live longer in a modern environment with reduced pathogen load and improved control of severe infections by antibiotics. All these data indicate a strong relationship among inflammation, genetics, CHD, and longevity.

Age‐Related Inflammatory Diseases

Abstract:  Alzheimers disease (AD) is a heterogeneous and progressive neurodegenerative disease which in Western societies mainly accounts for clinical dementia. A high proportion of women are affected by this disease, especially at a very advanced age, which might to a large extent be associated with the fact that women live longer. However, some studies suggest that incidence rates may be really increased in women. For this reason the influence of estrogens on the brain and the decrease of it during menopause are of special interest. After menopause, circulating levels of estrogens markedly decline, influencing several brain processes predicted to influence AD risk. The control of estrogens on oxidative stress, inflammation, and the cerebral vasculature might also be expected to increase AD risk. During the Womens Health Initiative Memory Study—a randomized, placebo‐controlled trial of women 65–79 years of age—oral estrogen plus progestin was seen to double the rate of developing dementia, with risk appearing soon after the treatment was initiated. On the basis of current evidence, hormone therapy (HT) is thus not indicated for the prevention of AD. Inflammation clearly occurs in pathologically vulnerable regions of the AD brain and the search for genetic factors influencing the pathogenesis of AD has led to the identification of numerous gene polymorphisms that act as susceptibility modifiers. Accordingly, several reports have indicated that the risk of AD is substantially influenced by several genetic polymorphisms in the promoter region, or other untranslated regions, of genes encoding inflammatory mediators. Here we review several data suggesting that inflammatory genetic variation may contribute to higher AD susceptibility in women too. All together this information may represent the basis both for future recognition of individuals at risk as well as for a pharmacogenomic approach in achieving drug responsiveness.

Immunosenescence and Anti-Immunosenescence Therapies: The Case of Probiotics

Aging is a complex process that negatively impacts the development of the immune system and its ability to function. Progressive changes in the T and B cell systems over the life span have a major impact on the capacity to respond to immune challenge. These cumulative age-associated changes in immune competence are termed immunosenescence. This process is mostly characterized by: (1) shrinkage of the T cell repertoire and accumulation of oligoclonal expansions of memory/effector cells directed toward ubiquitary infectious agents; (2) involution of the thymus and the exhaustion of naive T cells; and (3) chronic inflammatory status. Here we discuss possible strategies to counteract these main aspects of immunosenescence, in particular the role of the normalization of intestinal microflora by probiotics. A better understanding of immunosenescence and the development of new strategies to counteract it are essential for improving the quality of life of the elderly population.

Pathogenesis of autoimmune diseases associated with 8.1 ancestral haplotype: a genetically determined defect of C4 influences immunological parameters of healthy carriers of the haplotype.

Subjects with certain HLA alleles have a higher risk of specific autoimmune diseases than those without these alleles. The 8.1 ancestral haplotype (AH) is a common Caucasoid haplotype carried by most people who type for HLA-B8,DR3. It is unique in its association with a wide range of immunopathological diseases. To gain insight into the identification of the mechanism(s) of disease susceptibility of 8.1 AH carriers, we have investigated the prevalence of circulating immune complexes and non-organ-specific autoantibodies in healthy carriers of the haplotype. The results show that carriers of 8.1 AH display both a significant increased prevalence of immune complexes and higher titers of anti-nuclear autoantibodies. This AH carries a single segment characterized by no C4A gene. This null allele does not code for a functional C4A protein that likely plays an anti-inflammatory role being specialized in the opsonization and immunoclearance processes. So, this genetic defect has been claimed to allow that an increased production of autoantibodies directed vs. cells that have undergone apoptosis and are not efficiently disposed because a reduced antigenic clearance. The results obtained in the present study fit very well with this hypothesis. In the AH carriers the simultaneous high setting of tumor necrosis factor (TNF)-alpha may supply the autoantigens (providing an excess of apoptotic cells) that drive the autoimmune response. In conclusion, the C4 defect associated to the increased spontaneous release of TNF-alpha, modifying a certain number of immunological parameter may be the most characterizing feature of the 8.1 AH. In the majority of individuals, an autoimmune response clinically relevant will develop only in the presence of other immunological abnormalities.

Alzheimer's disease and genetics of inflammation: a pharmacogenomic vision

Inflammation plays a key role in Alzheimer disease, and dissecting the genetics of inflammation may provide an answer to the possible treatment. The next-generation therapy is based on a pharmacogenomics that will reconure new approaches to a drug used on definite people with specific dosage. The translation of pharmacogenomics into clinical practice will allow bold steps to be taken toward personalized medicine. In response to tissue injury elicited by trauma or infection, the inflammatory response sets in as a complex network of molecular and cellular interactions, directed to facilitate a return to physiological homeostasis and tissue repair. The role of an individuals genetic background and predisposition for the extent of an inflammatory response is determined by variability of genes encoding endogenous mediators that constitute the pathways of inflammation. Due to its clinical relevance, in this review, the view on genetics of inflammation will be illustrated through a description of the genetic basis of a specific inflammatory disease, Alzheimers disease (AD). Several studies report a significantly different distribution, in patients and controls, of proinflammatory genes, alleles of which are under-represented in control subjects and over-represented in patients affected by AD. These studies will permit the detection of a risk profile that will potentially allow both the early identification of individuals susceptible to disease and the possible design or utilization of drug at the right dose for a desired effect - a pharmacogenomic approach for this disease.

Opposite role of pro-inflammatory alleles in acute myocardial infarction and longevity: results of studies performed in a Sicilian population.

Abstract:  The major trait characterizing offspring in centenarians is a reduction in the prevalence of cardiovascular disease. Because a pro‐inflammatory genotype seems to contribute significantly to the risk of coronary heart disease, alleles associated with disease susceptibility would not be included in the genetic background favoring longevity, as suggested by our previous studies on inflammatory cytokines. To confirm whether genotypes of inflammatory molecules play an opposite role in atherosclerosis and longevity, we are studying the role of other proinflammatory alleles, such as pyrin and CCR5, in acute myocardial infarction and longevity. The results support the hypothesis that the genetic background favoring cardiovascular diseases is detrimental to longevity. In addition, they suggest that the centenarian genetic background may be useful for investigating genetic key components of age‐associated diseases that are characterized by a multifactorial etiology.

Polymorphisms of pro-inflammatory genes and Alzheimer's disease risk: a pharmacogenomic approach.

Clinically and pathologically Alzheimers disease (AD) represents a sequential progressive neurodegenerative disorder. AD is etiologically heterogeneous and accounts for a majority of dementia in western societies. Inflammation clearly occurs in pathologically vulnerable regions of the AD brain and the search for genetic factors influencing the pathogenesis of AD has lead to the identification of numerous gene polymorphisms that might act as susceptibility modifiers. Accordingly, several reports have indicated that the risk of AD is substantially influenced by several genetic polymorphisms in the promoter region, or other untranslated regions, of genes encoding inflammatory mediators, although not all the studies were replied. Here, we review several data suggesting that inflammatory genetic variation may contribute to AD susceptibility. All together this information may represent the basis both for future recognition of individuals at risk and for the pharmacogenomic driving of drug responsiveness.

Association between +1059G/C CRP polymorphism and acute myocardial infarction in a cohort of patients from Sicily: a pilot study.

Abstract:  Inflammation plays a role in all the phases of atherosclerosis, and increased production of the acute‐phase reactant, C‐reactive protein (CRP), predicts future cardiovascular events. Furthermore, CRP has been claimed to play a role in the pathogenesis of atherosclerosis; therefore, CRP polymorphisms might be associated with acute myocardial infarction (AMI). We have analyzed male patients affected by AMI and healthy age‐related male controls from Sicily for +1059G/C CRP single‐nucleotide polymorphism (SNP). There was a significantly higher frequency of +1059C SNP (P= 0.0008; OR 3.86) in patients compared to controls. CRP serum levels were significantly higher in C+ healthy subjects rather than in C− subjects (P= 0.0075). The results of the present pilot case–control study performed in a homogeneous caucasoid population suggest that +1059C CRP gene SNP is associated with AMI. In any case, the results of the present study should add to the growing body of evidence on the role of pro‐inflammatory genotypes in unsuccessful aging, determining susceptibility to immune‐inflammatory diseases such as coronary heart disease.