Angiotensin I-converting enzyme and plasminogen activator inhibitor-1 gene variants: risk of mortality and fatal cardiovascular disease in an elderly population-based cohort

Artificial Intelligence-Assisted Meta-Analysis of the Frequency of ACE I/D Polymorphisms in Centenarians and Other Long-Lived Individuals

Current research on the angiotensin-converting-enzyme (ACE) gene has yielded controversial results on whether different ACE polymorphisms are linked with human longevity. ACE polymorphisms are a risk factor for Alzheimer's disease and age-onset diseases that may contribute to the mortality of older people. Our goal is to consolidate existing studies, using artificial intelligence-assisted software to come to a more precise understanding of the role of the ACE gene in human longevity. The I (insertion) and D (deletion) polymorphisms in the intron are correlated with the levels of circulating ACE; homozygous D (DD) is high, and homozygous I (II) is low. Here, we performed a detailed meta-analysis of the I and D polymorphisms using centenarians (100+ years old), long-lived subjects (85+ years old), and control groups. ACE genotype distribution was analyzed across a total of 2054 centenarians and 12,074 controls, as well as 1367 long-lived subjects between the ages of 85-99, using the inverse variance and random effects methods. The ACE DD genotype was found to be favored in centenarians (OR: 1.41 (95% CI: 1.19-1.67), p < 0.0001) with a heterogeneity of 32%, and the II genotype slightly favored the control groups (OR: 0.81 (95% CI: 0.66-0.98), p = 0.03) with a heterogeneity of 28%, corroborating results from previous meta-analyses. Novel to our meta-analysis, the ID genotype was found to be favored in control groups (OR: 0.86 (95% CI: 0.76-0.97), p = 0.01) with a heterogeneity of 0%. The long-lived group showed a similar positive association between the DD genotype and longevity (OR: 1.34 (95% CI: 1.21-1.48), p < 0.0001) and a negative association between the II genotype and longevity (OR: 0.79 (95% CI: 0.70-0.88), p < 0.0001). The long-lived ID genotype did not show significant findings (OR: 0.93 (95% CI: 0.84-1.02), p = 0.79). In conclusion, the results suggest a significant positive association of the DD genotype with human longevity. However, despite the previous study, the results do not confirm a positive association of the ID genotype with human longevity. We suggest a few important paradoxical implications: (1) inhibition of ACE can increase longevity in model systems from nematodes to mammals, seemingly opposite to the finding in humans; (2) exceptional longevity associated with homozygous DD is also associated with age-related diseases with higher mortality risks in homozygous DD. We discuss ACE, longevity, and age-related diseases.

Gender difference and genetic variance in lipoprotein receptor-related protein 1 is associated with mortality

Cardiovascular diseases are an important health resource problem and studies have shown a genetic association between single nucleotide polymorphisms (SNPs) and cardiovascular diseases. According to the literature, lipoprotein receptor-related protein 1 (LRP1) is associated with coronary artery disease. The aim of the present study was to evaluate a possible association between different genotypes of LRP1 and all-cause and cardiovascular mortality from a gender perspective. In the present study, 489 elderly community-living people were invited to participate. Clinical examination, echocardiography and blood sampling including SNP analyses of LRP1 (rs1466535) were performed, including the T/T, C/T and C/C genotypes, and the participants were followed for 6.7 years. During the follow-up period, 116 (24%) all-cause and 75 (15%) cardiovascular deaths were registered. In the female population, the LRP1 of the T/T or C/T genotype exhibited a 5.6-fold increased risk of cardiovascular mortality and a 2.8-fold increased risk of all-cause mortality compared with the C/C genotype. No such genotype differences could be seen in the male population. Gender differences could be seen regarding the risk of mortality in the different genotypes. Females with the LRP1 T/T or C/T genotypes exhibited a significantly increased risk of both all-cause and cardiovascular mortality compared with the C/C genotypes. Therefore, more individualized cardiovascular prevention and treatment should be prioritized. However, since this was a small study, the observations should only be regarded as hypothesis-generating.

Puzzling role of genetic risk factors in human longevity: "risk alleles" as pro-longevity variants

Complex diseases are major contributors to human mortality in old age. Paradoxically, many genetic variants that have been associated with increased risks of such diseases are found in genomes of long-lived people, and do not seem to compromise longevity. Here we argue that trade-off-like and conditional effects of genes can play central role in this phenomenon and in determining longevity. Such effects may occur as result of: (i) antagonistic influence of gene on the development of different health disorders; (ii) change in the effect of gene on vulnerability to death with age (especially, from “bad” to “good”); (iii) gene–gene interaction; and (iv) gene–environment interaction, among other factors. A review of current knowledge provides many examples of genetic factors that may increase the risk of one disease but reduce chances of developing another serious health condition, or improve survival from it. Factors that may increase risk of a major disease but attenuate manifestation of physical senescence are also discussed. Overall, available evidence suggests that the influence of a genetic variant on longevity may be negative, neutral or positive, depending on a delicate balance of the detrimental and beneficial effects of such variant on multiple health and aging related traits. This balance may change with age, internal and external environments, and depend on genetic surrounding. We conclude that trade-off-like and conditional genetic effects are very common and may result in situations when a disease “risk allele” can also be a pro-longevity variant, depending on context. We emphasize importance of considering such effects in both aging research and disease prevention.

Are polymorphisms in the ACE and PAI-1 genes associated with recurrent spontaneous miscarriages?

PROBLEM

To determine whether the ACE D/D genotype or the combination of PAI-1 4G/4G and ACE D/D genotypes may serve as a risk factor for recurrent pregnancy loss.

METHOD OF STUDY

Buccal swabs were obtained from 120 women experiencing recurrent pregnancy loss and from 84 fertile control women. DNA was extracted from the buccal swab samples using the Qiagen DNA Mini Kit (Qiagen), followed by multiplex polymerase chain reaction (PCR). PCR products were analyzed for the ACE gene polymorphism, which consists of the insertion or deletion (I/D) of a 287-bp fragment in intron 16, and the PAI-1 4G/4G genotype.

RESULTS

No significant differences in specific ACE gene mutations were observed when patients experiencing recurrent miscarriage were compared with control women. When the frequencies of homozygous mutations for ACE D/D and PAI-I 4G/4G were compared between recurrent aborters and controls, again no significant differences in the prevalence of the combination of these gene mutations were noted.

CONCLUSION

Homozygosity for the D allele of the ACE gene and the combination of the D/D genotype with two 4G alleles of the PAI-1 promoter gene are not associated with a significant increase in the risk of recurrent miscarriage.

Plasminogen activator inhibitor-1 4G/5G polymorphism and risk of ischemic stroke: a meta-analysis

This study investigated the hypothesis that the insertion/deletion (4G/5G) polymorphism of the plasminogen activator inhibitor type-1 gene affects the risk for ischemic stroke, since results concerning this association have been controversial. We therefore performed a meta-analysis of published data regarding this issue. A comprehensive electronic search was carried out until January 2006. The analysis was performed using random-effects models and meta-regression. Eighteen eligible studies were retrieved (15 case-control studies and three cohort studies). The case-control studies included 3104 cases and 4870 control individuals concerning the contrast of 4G/4G versus remaining genotypes. The 4G pooled allele frequencies in cases and controls were 54.21 and 54.75%, respectively. Overall, the per-allele odds ratio of the 4G allele was 0.98 (95% confidence interval, 0.858-1.121). Regarding genotypes, we derived nonsignificant odds ratios in all contrasts. The subanalysis including the three studies with a prospective design in the 4G/4G versus 5G/5G contrast derived a significant result (relative risk, 0.523; 95% confidence interval, 0.353-0.775), but the estimated effect size was insignificant when cohort and case-control studies were analyzed together (relative risk, 0.848; 95% confidence interval, 0.662-1.087). We failed to demonstrate a significant association between the 4G/5G polymorphism and ischemic stroke under basal conditions. Determination of plasminogen activator inhibitor type-1 function seems of much higher clinical value than determination of the 4G/5G polymorphism. The effect of this genotype on risk of ischemic stroke in acute stressful diseases and the role of cohort studies in genetic epidemiology, however, warrant further investigation.

Plasminogen activator inhibitor type 1 gene polymorphisms and haplotypes are associated with plasma plasminogen activator inhibitor type 1 levels but not with myocardial infarction or stroke

BACKGROUND

The 4G allele in the promoter region of the plasminogen activator inhibitor type 1 (PAI-1) gene is associated with higher plasma PAI-1 levels and activity, but its association with cardiovascular diseases is unclear. We investigated the association of polymorphisms and common haplotypes of the PAI-1 gene with plasma PAI-1 levels, as well as the risk of myocardial infarction and stroke.

METHODS AND RESULTS

This study is a prospective analysis of 2995 community-based participants (41% blacks and 51% women) aged 70 to 79 years old in the Health, Aging, and Body Composition Study. From 1997/1998 to 2001, 177 myocardial infarction events and 101 stroke events were identified. In addition to the 4G/5G polymorphism, 2 potential functional variants and other 4 haplotype-tagging variants were genotyped. In general linear models, the 4G allele was associated with higher PAI-1 levels after adjusting for age, sex, race, and site (26, 29, and 32 ng/mL for 5G/5G, 4G/5G, and 4G/4G, respectively; P for trend < .0001), but none of the other 6 polymorphisms was associated with PAI-1 levels. Haplotype analysis produced similar results. However, in Cox proportional hazard models, neither the polymorphisms nor the common haplotypes of the PAI-1 gene was associated with the risk of either myocardial infarction or stroke.

CONCLUSIONS

The 4G allele is associated with higher PAI-1 levels, but this study does not support an association of the PAI gene polymorphisms with the risk of either myocardial infarction or stroke.

Common promoter polymorphisms of inflammation and thrombosis genes and longevity in older adults: The cardiovascular health study

Inflammatory response genes may influence life span or quality at advanced ages. Using data from the population-based cardiovascular health study (CHS) cohort, we examined the associations between promoter polymorphisms of several inflammation and thrombosis genes with longevity. We ascertained genotypes for interleukin (IL)-6 -174 G/C, beta-fibrinogen -455 G/A, plasminogen activator inhibitor (PAI)-1 -675 4G/5G, and thrombin-activatable fibrinolysis inhibitor (TAFI) -438 G/A in 2224 men and women > or = 65 years old at baseline. During 10 years of follow-up, men with the TAFI -438 A/A genotype had decreased mortality due to all causes, and lived, on average, 0.9 more years of life, or 1.1 more years of healthy life, than men with the -438 G allele. The effects of TAFI -438 G/A in women were smaller and not statistically significant. PAI-1 4G/4G genotype appeared to be associated with lower non-cardiovascular mortality in men, but with greater cardiovascular mortality in women. In exploratory analyses, we observed a possible interaction among anti-inflammatory drugs, interleukin-6 -174 C/C genotype, and longevity. These findings suggest that modulators of fibrinolytic activity may have a generalized influence on aging, and merit further investigation in studies of genetic determinants of human longevity.

4G/4G Genotype of PAI-1 Gene Is Associated With Reduced Risk of Stroke in Elderly

Background and Purpose— Plasminogen activator inhibitor type 1 (PAI-1) is the main inhibitor of fibrinolysis, and high levels may increase the risk of cardiovascular disease. The 4G/5G polymorphism affects PAI-1 gene transcription with lower levels of plasma PAI-1 in the presence of the 5G allele. We investigated whether plasma PAI-1 and 4G/5G genotype would predict the occurrence of cardiovascular events at old age.

Methods— Relative risks for cardiovascular events and all-cause mortality were obtained in strata of PAI-1 activity and 4G/5G genotype in a population-based study of 637 Dutch elderly with 7.8 years of follow-up.

Results— The 4G/4G genotype was associated with a decreased risk of stroke (relative risk [RR]=0.4; 95% CI, 0.2 to 0.9), transient ischemic attack (RR=0.3; 95% CI, 0.1 to 0.8), and cardiovascular mortality (RR=0.5; 95% CI, 0.3 to 1.0) after adjustment for age, sex, and time of blood sampling. 4G carriers had an increased risk of myocardial infarction, but this was not statistically significant. Subjects with high plasma PAI-1 activity were at increased risk of stroke (RR=3.3 in highest versus lowest tertile; 95% CI, 1.5 to 7.1), cardiovascular mortality (RR=2.3; 95% CI, 1.2 to 4.4), and all-cause mortality (RR=1.5; 95% CI, 1.1 to 2.1).

Conclusions— Our results provide support for a protective effect of the 4G allele against stroke, which is notable given the direct relationship between stroke and PAI-1 activity. We hypothesize that a local increase in tissue PAI-1 associated with the 4G allele may stabilize plaques, thereby reducing the risk of cerebrovascular disease.

No increase in mortality and morbidity among carriers of the C282Y mutation of the hereditary haemochromatosis gene in the oldest old: the Leiden 85-plus study

BACKGROUND

The C282Y mutation in the gene for haemochromatosis (HFE) has been associated with various diseases at middle age. However, recent studies indicate that penetrance of the C282Y mutation is low. We explored the association between the C282Y mutation, iron metabolism, and morbidity and mortality in participants of the Leiden 85-plus.

STUDY DESIGN

A cross-sectional comparison and prospective follow-up was conducted in two unselected cohorts of 661 and 552 subjects. All subjects were aged 85 years and over. We determined the prevalence of C282Y homozygous and heterozygous subjects, and the association between the C282Y mutation and iron metabolism, all-cause and specific causes of death.

RESULTS

Prevalence of C282Y homozygosity in both cohorts was 0.2% (1/661 and 1/552, respectively) and of C282Y heterozygosity was 12.4% (82/661) and 11.4% (63/552), respectively. These estimates coincide exactly with reported estimates in younger age groups. Median ferritin level was 97 microg L-1 (IQR 39-162) for heterozygous carriers and 89 microg L-1 (IQR 41-157) for noncarriers (P = 0.66). The serum ferritin concentration for one C282Y homozygous subject, a woman aged 86 years at the time of enrollment in 1986, was 392 microg L-1. Cardiovascular morbidity was comparable between the C282Y heterozygous subjects and the noncarriers in both study cohorts. All-cause and cardiovascular mortality of carriers of the C282Y mutation was similar to that in noncarriers.

CONCLUSIONS

We found two C282Y homozygous subjects, illustrating that homozygosity can be compatible with survival in very old ages. C282Y heterozygosity was not associated with history of cardiovascular disease morbidity, all cause mortality, cardiovascular mortality, or biochemical phenotype of haemochromatosis at old age.

Deletion allele of the angiotensin-converting enzyme gene as a risk factor for pneumonia in elderly patients

PURPOSE

Aspiration due to an age-related reduction in cough is a major cause of pneumonia in elderly persons. Because the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene (ACE) has been associated with the cough reflex, we studied whether this genetic polymorphism was also associated with the risk of pneumonia.

SUBJECTS AND METHODS

We studied 1011 elderly inpatients (221 men and 790 women, mean [+/- SD] age of 82 +/- 7 years) in a long-term care hospital. The association between the ACE I/D polymorphism and the incidence of pneumonia (defined using specific criteria that included radiographic abnormalities) was assessed during an 8-month period that excluded the winter. Data were analyzed using proportional hazards models, with adjustment for age, sex, and other potential confounders.

RESULTS

During follow-up, 87 cases (9%) of pneumonia occurred, 38 of which were fatal. The ACE DD allele (vs. ID + II) was associated with an increased risk of pneumonia (relative risk [RR] = 2.9; 95% confidence interval [CI]: 1.7 to 4.8, P < 0.001) and fatal pneumonia [RR = 4.4; 95% CI: 2.1 to 9.0; P < 0.0001).

CONCLUSIONS

The ACE D allele is an independent risk factor for pneumonia in elderly persons.

Association of APOE epsilon2/epsilon3/epsilon4 and promoter gene variants with dementia but not cardiovascular mortality in old age

The common apolipoprotein E (APOE) alleles epsilon2, epsilon3, and epsilon4 are associated with the risk of dementia and cardiovascular disease. Recently, two functional variants (- 219G/T and -491A/T) were identified in the promoter of the APOE gene that enable a further characterization of the role of the APOE locus in disease. We investigated the contribution of these APOE gene variants to dementia and cardiovascular mortality in old age using a population-based cohort of 648 subjects aged 85 years and over (Leiden 85-Plus Study). Genotypes containing an APOE epsilon4 allele were associated with a 4.1-fold (95% CI, 2.2-7.7) increased risk of dementia as compared to the epsilon3/epsilon3 genotype in old subjects. Moreover, homozygosity for the -219T allele was found to be associated with a 2.4-fold (95% CI, 1.0-5.8) increased risk independently of epsilon2 and epsilon4; the -491A/T variant was not associated with dementia. Over a 10-year follow-up period, the risk of cardiovascular mortality was not increased among epsilon4 carriers (RR, 0.6; 95% CI, 0.4-1.0) or -219T homozygous subjects (RR, 1.1; 95% CI, 0.7-1.7), nor did it decrease among -491T homozygous subjects (RR, 1.4; 95% CI, 0.6-3.1). In conclusion, both the APOE epsilon2/epsilon3/epsilon4 and the -219G/T variant were identified as risk factors for dementia but not cardiovascular mortality in old age. Our results support the hypothesis that both the isoform and the amount of APOE may influence the risk of dementia. Furthermore, they emphasize that variation at the APOE locus has a higher impact on the risk of dementia than on the risk of cardiovascular disease in old age.

Biological ageing research in the Netherlands

After an introduction on the development of biological ageing research in the Netherlands during the past decades, 606 papers on aging published by Dutch institutes in the period 1991-2000, collected from PubMed, were analysed for their relevance to research into biological ageing. For the period 1996-2000, the total number of research papers on biological ageing amounted to 142, which accounts for 23% of all publications on ageing in that period. The number of publications per year did not change. On the basis of these papers and additional information provided by research groups a comprehensive overview of biological ageing research in the Netherlands is presented, together with an extensive literature list. Ageing of the central nervous system (CNS), of the endocrinological system and of the cardiovascular system are the topics most studied. It is concluded that general biological ageing research has not increased in the Netherlands over the last ten years, and that the infrastructure for basic biological ageing research in the Netherlands is weak.

PAI-1 promoter 4G/5G genotype as an additional risk factor for venous thrombosis in subjects with genetic thrombophilic defects

Impaired fibrinolysis as a result of increased plasminogen activator inhibitor-1 (PAI-1) levels in plasma is a common finding in patients with deep vein thrombosis (DVT). A 4G/5G polymorphism in the promoter region of the PAI-1 gene has been reported to influence the levels of PAI-1. The 4G allele was found to be associated with higher plasma PAI-1 activity (act), but contradictory results on the incidence of the 4G allele in DVT patients have been reported. The aim of this study was to analyse whether the PAI-1 promoter 4G/5G genotype increases the risk of venous thrombosis in subjects with thrombophilic defects, and to determine the distribution of the PAI-1 4G/5G genotype and its relation to plasma PAI-1 levels in 190 unrelated patients with DVT in comparison with a control group of 152 healthy subjects. No differences between the 4G/5G allele distribution in the DVT group (0.43/0.57) and in the control group (0.42/0.58) were observed. However, the presence of the 4G allele significantly increased the risk of thrombosis in patients with other thrombophilic defects. Significantly higher PAI-1 levels were observed in DVT patients than in the controls. Our results also showed significant differences in the plasma levels of PAI-1 antigen (ag) and PAI-1 act among the 4G/5G genotypes in DVT patients. A multivariate analysis revealed that, in the DVT group, PAI-1 ag levels were influenced by the 4G allele dosage, triglyceride levels and body mass index (BMI). The influence of the 4G allele dosage on PAI-1 levels was independent of the triglyceride levels and BMI. In the control group, no significant correlation between PAI-1 levels and 4G allele dosage was observed. In conclusion, the PAI-1 promoter polymorphism was found to have an influence on PAI-1 levels in DVT patients and on the risk of venous thrombosis in subjects with other genetic thrombophilic defects.

Common gene variants, mortality and extreme longevity in humans

Genetic factors influence variation in human life span. The fast technological advancements in genome research and the methodology for statistical analysis of complex traits provided new tools to unravel these genetic influences. Most of the genetic epidemiology and quantitative genetics is focused on the dissection of the genetic component of specific diseases rather than of human life span. Nevertheless, common variants of 22 genes have been tested for their contribution to mortality in the general population and extreme longevity in one or more studies. These studies provide indications as to the nature of biological pathways that might play a role in human ageing. Perhaps even more important at this time is the fact that they give valuable insights in the strengths and weaknesses of current strategies to identify gene variants affecting human life span and point at more powerful approaches.

Genetics of human aging. The search for genes contributing to human longevity and diseases of the old

An aging population of humans reflects early-onset morbidity and mortality as well as late-onset disease in the phase when the mortality rate doubles and, finally, longevity of extremely long-lived subjects. Genetic influences have been reported to be relevant for each of these three phases. A growing field in genetic research is aimed at the identification of genes involved in multifactorial diseases of the old and in longevity. Important issues in these studies include the definition of phenotype, which maximally highlights the genetic contribution, whether earlier and later onset phenotypes have loci in common, and how to rank or reject the many candidate disease loci found in different studies. These issues will be illustrated from research on cardiovascular disease and osteoarthritis.