Genetic risk profiles for Alzheimer's disease: Integration of APOE genotype and variants that up-regulate inflammation

BACKGROUND: A number of studies associate Alzheimer's disease with APOE polymorphism and alleles which favor the increased expression of immunological mediators such as cytokines or acute phase proteins. We integrated this information to better define risk and determine the relative importance of APOE and immunological mediators. METHODS: We investigated functional gene variants for APOE, IL-10 (3 loci), ACT (2 loci), HMGCR, IL-1alpha, IL-1beta, TNF-alpha, IFN-gamma, and IL-6 found for 260 AD patients and 190 controls enrolled in Northern Italy. A fuzzy latent classification approach, namely grade-of-membership analysis (GoM), was taken to identify extreme pure type risk sets, or profiles. …

Acute Myocardial Infarction and Proinflammatory Gene Variants

We identified four genetic risk sets for acute myocardial infarction (AMI) from information on functional gene variants that favor inflammation or modulate cholesterol metabolism: IL6 -174 G/C, TNF -308 G/A, IL10 -1082 G/A, SERPINA3 -51 G/T, IFNG +874 T/A, HMGCR -911 C/A, and APOE ε2/3/4; 316 patients and 461 healthy subjects, all Italian. Putative risk alleles are shown underlined. The sets were identified using grade-of-membership analysis. Membership scores in the sets are automatically generated for individuals. The ''low intrinsic risk'' set had alleles that downregulate inflammation and cholesterol synthesis (IL6, TNF, ILl0, HMGCR). ''AMI across a broad age range'' carried multiple pr…

Association between the interleukin-1beta polymorphisms and Alzheimer's disease: a systematic review and meta-analysis.

Abstract The pro-inflammatory cytokine interleukin(IL)-1β is a main component in inflammatory pathways and is overexpressed in the brain of Alzheimer's disease (AD) patients. Several studies report associations between IL-1β polymorphisms and AD, but findings from different studies are controversial. Our aim was to verify the correlation between the single nucleotide polymorphisms (SNPs) of the IL-1β, at sites − 511 and + 3953, and AD by meta-analysis. Computerized bibliographic searches of PUBMED and AlzGene database ( http://www.alzgene.org ) were supplemented with manual searches of reference lists. There is evidence for association between IL-1β + 3953 SNP and AD, with an OR = 1.60 (95%…

Interleukin-10 promoter polymorphism in sporadic Alzheimer's disease.

Proinflammatory cytokines and acute-phase proteins play an important role in Alzheimer's disease (AD) neurodegeneration, and common polymorphisms of genes controlling their high production have been shown to be associated with AD. Thus, AD patients display a proinflammatory genotype and the control of inflammation might play a protective role in AD development. By sequence-specific probes, we have evaluated the role of anti-inflammatory cytokine interleukin(IL)-10 in AD, by analysing in 132 AD patients and 213 healthy controls the prevalence of three different haplotypes, involving three single-nucleotide polymorphisms (SNPs) at -1082 (G--A), -819 (C--T) and -592 (C--A) nucleotides of IL-10…

Tumor necrosis-factor-alpha -308 A/G polymorphism is associated with age at onset of Alzheimer's disease.

Abstract Pro-inflammatory cytokines and acute-phase proteins play an important role in Alzheimer's disease (AD) neurodegeneration, and common polymorphisms of genes controlling their production have been shown to be associated with AD. Tumor necrosis factor (TNF)-α is an inflammatory cytokine involved in the local immune response occurring in the central nervous system of AD patients. Genetic variation could contribute to the risk of developing AD or influence the age at the onset of the disease. We genotyped 222 patients (152 women, 70 men; age range 60–87) and 240 non-demented age-matched healthy controls for TNF-α −308 G/A single nucleotide polymorphism (SNP). No significant differences …

Immunotherapy in patients with Alzheimer's disease (AD) is rapidly becoming a hot topic of modern geriatric and clinical gerontology. Current views see immunization with Aβ peptide, the amyloidogenic protein found in senile plaque of AD patient's brains, or the infusion of preformed antibody specific for human Aβ, as possible therapeutic approaches to improve the cognitive status in the disease. Animal models of the disease have provided positive results from both approaches. Thus, an initial clinical trial using immunization with human Aβ in AD patients was started, but then shortly halted because of an unusually high incidence (6%) of meningoencephalitis. A long and currently ongoing deba…

Role of prothrombotic polymorphisms in successful or unsuccessful aging.

The study of the genetic profile of centenarians aims to identify the genes and allelic variants which may influence a greater life expectancy and that can be considered as predisposing factors associated to the aging diseases, such as Alzheimer. Centenarians, that represent a cohort of selected survivors, show an hypercoagulability state characterised by striking signs of high coagulation enzyme activity, as directly assessed by the tested higher plasma level of some important factors involved in the haemostasis balance. Anyway, these individuals seem to have a reduced susceptibility to dementia, as well as to cardiovascular events. In this study we analyze the frequencies of Leiden Factor…

Apolipoprotein E Genotypic Frequencies Among Down Syndrome Patients Imply Early Unsuccessful Aging for ApoE4 Carriers

Down syndrome (DS) might be considered a model for unsuccessful and early aging, possibly accelerated for those who carry the APOE4 allele associated with common age-related diseases, e.g., Alzheimer's disease and a poor prognosis after acute myocardial infarction, causing lower ApoE4 frequencies among the very old in general populations. We compared ApoE genotypic frequencies found for healthy adults (n = 211, age 90) to those found for DS patients (n = 106, mean age 9 years), all living in western Sicily. We found that the frequency of the ApoE23 genotype increased with age among the healthy adults (8.5%, 6.4%, 19.7%; p = 0.024) while ApoE34 frequency decreased (16.1%, 12.6%, 4.1%; p = 0.…

Role of cyclooxygenae-2 and 5-lypoxygenase polymorphisms in Alzheimer's disease in a population from northern Italy:implications for pharmacogenomics

Alzheimer's disease (AD) is a neurodegenerative disorder clinically characterized by cognitive deficit with progressive worsening of memory. Recent data indicate that neurons, as well as other brain cells, can express enzymes such as cyclooxygenases (COXs) and 5-lipoxygenase (5-LO) which are considered important in inflammatory cells. Moreover, it has been demonstrated that COX-2 and 5-LO enzymes play a considerable role in the pathophysiology of AD. In order to assess the possible role of COX-2 and 5-LO single nucleotide polymorphisms (SNPs) in AD, we examined their distribution in 341 AD patients and 190 controls from Northern Italy. A significant difference was observed in the distributi…

Association Between the HLA-A2 Allele and Alzheimer Disease

In the elderly, the most common cause of dementia is Alzheimer disease (AD), which is responsible for the age-related progressive neurodegenerative inflammatory condition mediated by the disease. It has been seen that several genetic and environmental factors are involved in AD onset. Epidemiologic data suggest that some genetic determinants of AD might reside in those polymorphisms that regulate immune inflammatory responses, such as the major histocompatibility complex (MHC). Therefore, several MHC polymorphisms have been in the spotlight of a large number of AD association studies. A possible association of HLA-A2 allele with increased susceptibility to AD has been the subject of debate …

Does Down's syndrome support the homocysteine theory of atherogenesis?

Abstract Down syndrome (DS) is generally considered as an “atheroma-free model”. In this preliminary study, we investigated homocysteine, folate and Vitamin B 12 levels in 13 DS patients (male, average age 60 years) and 20 age-matched individuals. We also studied lipid fractions, and polymorphisms for Cystothionine β-synthase (CBS), 5,10-methyl-tetrahydro-folate reductase (MTHFR) and apolipoprotein E (Apo-E) genes. However, DS patients with the MTHFR TT genotype showed an increased of plasma homocysteine (tHcy). Our results indicate that this group of “healthy old” Down syndrome patients, although showing some classical biochemical risk factors for atherosclerosis, did not suffer clinical c…

Association between the HFE mutations and unsuccessful ageing: a study in Alzheimer's disease patients from Northern Italy

Mutations in the class I-like Major Histocompatibility Complex gene HFE are associated with hereditary hemochromatosis (HH), a disorder caused by excessive iron uptake. Three common mutations have been found: C282Y, H63D, and S65C. Moreover, several studies have suggested that HFE mutations may be involved in several age-related chronic diseases such as Alzheimer's disease (AD) and coronary heart disease, but apparently paradoxically also with longevity. In particular, in AD, patients carrying the H63D allele have been suggested to have a mean age at onset of 72 vs. 77 years for those who were homozygous for the wild-type allele. Thus, it seems that H63D mutations may anticipate sporadic AD…

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

Clinically and pathologically Alzheimer's 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, altho…

Association between the polymorphism of CCR5 and Alzheimer's disease: results of a study performed on male and female patients from Northern Italy.

Alzheimer's disease (AD) is the most common cause of dementia in Western society. The prevalence of AD is greater in women than in men, largely due to longevity and survival differences favoring women. However, some studies suggest that incidence rates may really be increased in women. One possible factor influencing AD incidence in women is the loss of ovarian estrogens production after menopause, which might be involved in AD pathogenesis. Estrogens seem to influence some neuronal functions. Many of these actions appear beneficial (i.e., neuroprotective action against a variety of insults, as oxidative stress, and reduction of beta-amyloid plaques formation). Furthermore, several studies …

Age-Related Inflammatory Diseases: Role of Genetics and Gender in the Pathophysiology of Alzheimer's Disease

Alzheimer's 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 oxid…

Genetics of Neurodegenerative Disorders

Predictive diagnostics and personalized medicine for the prevention of chronic degenerative diseases

Abstract Progressive increase of mean age and life expectancy in both industrialized and emerging societies parallels an increment of chronic degenerative diseases (CDD) such as cancer, cardiovascular, autoimmune or neurodegenerative diseases among the elderly. CDD are of complex diagnosis, difficult to treat and absorbing an increasing proportion in the health care budgets worldwide. However, recent development in modern medicine especially in genetics, proteomics, and informatics is leading to the discovery of biomarkers associated with different CDD that can be used as indicator of disease’s risk in healthy subjects. Therefore, predictive medicine is merging and medical doctors may for t…

Analysis of polymorphisms Leiden Factor V G1691A and prothrombin G20210A as risk factors for acute myocardial infarction.

Thrombotic risk increases in elderly, therefore, the understanding of the genetic predisposition of hypercoagulability could make the difference in the prevention of venous and/or arterial thrombotic events. Laboratory evaluation of hyperfibrinogenemia, increased Factor VII levels, antiphospholipid antibodies presence and hyperhomocysteinemia are considered to have a consistent high predictivity for arterial thrombophilic diseases. Anyway, a large debate exists on the validity of testing Leiden Factor V (FV) G1691A and/or prothrombin (FII) G20210A polymorphisms in patients affected by arterial thrombotic diseases, despite of the several observations described. Here we report data strongly s…

Pathophysiology of age-related diseases

Abstract A Symposium regarding the Pathophysiology of Successful and Unsuccessful Ageing was held in Palermo, Italy on 7-8 April 2009. Three lectures from that Symposium by G. Campisi, L. Ginaldi and F. Licastro are here summarized. Ageing is a complex process which negatively impacts on the development of various bodily systems and its ability to function. A long life in a healthy, vigorous, youthful body has always been one of humanity's greatest dreams. Thus, a better understanding of the pathophysiology of age-related diseases is urgently required to improve our understanding of maintaining good health in the elderly and to program possible therapeutic intervention.

Association between HFE mutations and acute myocardial infarction: a study in patients from Northern and Southern Italy.

There is interest in the role of iron in age-related diseases such as atherosclerosis. Tissue iron deposition could be harmful, because Fe(2+) can react with H(2)O(2) to form OH(-) radicals and Fe(2+) can react with O(2) to form reactive oxygen species. Free radicals react with cell membranes and cell organelles and could lead to the development of atherosclerosis by initiating lipid peroxidation. Hereditary hemochromatosis provides an opportunity for studying the effects of iron on cardiovascular disease. Some studies have shown that individuals who carried HFE mutations may be at greater risk of developing coronary heart disease than those without the mutations. In contrast, a large numbe…

Association between the polymorphisms of TLR4 and CD14 genes and Alzheimer's disease.

Alzheimer's disease (AD) is a heterogeneous and progressive neurodegenerative disease which in Western society mainly accounts for clinical dementia. Inflammation plays a key role in AD and dissecting the genetics of inflammation may provide an answer to the possible treatment. Hence, the better understanding of different molecular and cellular inflammatory mechanisms is crucial for complete knowledge of AD pathophysiology, and for its prevention and drug therapy. Accordingly, in the present study we evaluated whether the pro-inflammatory polymorphisms of lipopolysaccaride-receptors, +896A/G Toll-Like Receptor (TLR4) and -260C/T CD14, are risk factors for AD. The study included both 626 AD …

INNATE IMMUNITY AND INFLAMMATION IN AGEING: A KEY FOR UNDERSTANDING AGE-RELATED DISEASES.

Abstract The process of maintaining life for the individual is a constant struggle to preserve his/her integrity. This can come at a price when immunity is involved, namely systemic inflammation. Inflammation is not per se a negative phenomenon: it is the response of the immune system to the invasion of viruses or bacteria and other pathogens. During evolution the human organism was set to live 40 or 50 years; today, however, the immune system must remain active for much a longer time. This very long activity leads to a chronic inflammation that slowly but inexorably damages one or several organs: this is a typical phenomenon linked to ageing and it is considered the major risk factor for a…

Opposite effects of interleukin 10 common gene polymorphisms in cardiovascular diseases and in successful ageing: genetic background of male centenarians is protective against coronary heart disease

Many aspects of ageing involve inflammatory processes. We evaluated the association with longevity of alleles of IL10 and TNFa, known to have opposite functions in inflammatory reactions, IL-10 acting predominantly as an anti-inflammatory and TNF-a as a proinflammatory factor. The number of male centenarians homozygous for the –1082G genotype, suggested to be associated with high IL-10 production, was significantly increased in comparison with younger control subjects. No significant differences were observed between women and controls. The genotypic frequencies of the TNFa promoter SNPs 308G and 308A, suggested to be associated with low and high TNF-a production respectively, were not sign…

Sharing pathogenetic mechanisms between acute myocardial infarction and Alzheimer's disease as shown by partially overlapping of gene variant profiles.

Abstract Gene variants that promote inflammation and cholesterol metabolism have been associated with acute myocardial infarction (AMI) and Alzheimer's disease (AD). We investigated a panel of relevant polymorphisms to distinguish genetic backgrounds for AMI and AD: IL10 -1082G/A, IL6 -174G/C, TNF -308G/A, IFNG +874T/A, SERPINA3 -51G/T, HMGCR -911C/A, APOE e2/3/4 (280 AMI cases, 257 AD cases, and 1307 population controls, all Italian (presumed risk alleles are shown in bold). Six genetic risk sets I to VI were identified by fuzzy latent classification: I had low risk; II and III had low risk before age 65 (II, III); low risk sets lacked pro-inflammatory alleles for HMGCR-TNF-APOE. Pro-infla…

Systematic review by meta-analyses on the possible role of TNF-alpha polymorphisms in association with Alzheimer's disease.

It has been hypothesized that polymorphisms of Tumor Necrosis Factor (TNF)-alpha gene affect the risk of developing Alzheimer's disease (AD). However, results of different studies are often inconsistent. Our aim was to investigate by meta-analysis the association of the common polymorphisms comprehensively defining the genetic variability of the TNF-alpha gene with AD risk. Hence, the results being stated are of a meta-analysis across studies, and that this meta-analysis does not invalidate the results of the individual studies previously performed. Seventeen studies that investigated the association between 5 TNF-alpha polymorphisms (-850, -308, -863, -238, and -1031) and AD were retrieved…

Interleukin-6 gene polymorphism is an age-dependent risk factor for myocardial infarction in men.

Summary Several studies show that inflammatory components may contribute to atherosclerosis and increase the risk for myocardial infarction (MI). Interleukin-6 (IL-6) is a key pro-inflammatory and immune-modulatory cytokine of relevance for cardiovascular diseases. In this case-control study, 200 patients with MI and 257 healthy controls were genotyped for the polymorphism present in −174 promoter region of the IL-6 gene. Plasma concentrations of IL-6 and C-reactive protein (CRP) in a group of patients and controls were measured. The −174 C allele was associated with an increased risk of developing MI (OR = 2.886, c.i. = 1.801–4.624, P = 0.0001) in older patients, while no association was f…