Antiaging Treatments Have Been Legally Prescribed for Approximately Thirty Years

There is an interesting divergence between the achievements of geriatrics and gerontology. On the one hand, during the last 30 years physicians in many developed countries have successfully prescribed several medicines to cure various symptoms of senescence. On the other hand, the influence of such medicines on human life span practically has not been studied. The most common of the relevant medicines are nootropic piracetam, gamma-aminobutyric acid (GABA), selegiline, Ginkgo biloba, pentoxifylline, cerebrolysin, solcoseryl, ergoloid, vinpocetin, sertraline, and estrogens, among others. Available data from human clinical practices and experimental animal studies indicate that treatments with these drugs improve learning, memory, brain metabolism, and capacity. Some of these drugs increase tolerance to various stresses such as oxygen deficit and exercise, stimulate the regeneration of neurons in the old brain, and speed up the performance of mental and physical tasks. This means that modern medicine already has "antiaging" treatments at its disposal. However, the influence of such treatments on the mean and maximal life span of humans, and on the age trajectory of a human survival curve has been poorly studied. The increase in human life expectancy at birth in the second half of the last century was mostly caused by the better survival at the old and oldest old rather than at the young ages. In parallel, the consumption of brain protective and regenerative drugs has been expanding in the elderly population. We provide evidence in support of the idea that the consumption of medicines exerting antiaging properties may contribute to the increase in human longevity.

Individual aging and mortality rate: how are they related?

Many researchers working in the area of aging and longevity base their conclusions on the behavior of empirical age trajectories of mortality rates. In such analyses, changes in the slope of the logarithm of the mortality curve are often associated with changes in the rate of individual aging. We show that such interpretation may be incorrect: the changes in the slope of this curve do not necessarily correspond to the changes in the rate of individual aging. We use three models of mortality and aging to illustrate this statement. The first one is based on the idea of frailty. We show that changes in frailty distribution alone may be responsible for changes in the slope. The second model exploits the idea of saving lives. It evaluates changes in mortality rate after elimination of lethal stressful events. The third model uses the idea of Strehler and Mildvan (1960). It shows that changes in the rate of individual aging may take place without changes in the slope of the logarithm of the mortality curve.

[Serotonin transporter gene polymorphism and factors influencing mental and physical health in aging]

Genetic predisposition is thought to exert a certain influence on the indices related to longevity and quality of life. Many of the indices, namely cognitive functioning, stress resistance, metabolism control, may be related to serotonin activity. To study polymorphic serotonin transporter gene variants and their association with features relevant for survival and longevity prognosis, a sample of elderly Russians from Moscow community recruited in the project "Stress-related mechanisms in Russia", comprising 196 subjects, mean age 76.2+/-5.3 years, 155 men, 41 women, has been genotyped. Allele and genotype frequencies have been estimated in 3 groups, aged 60-69, 70-79 and 80-87 years, respectively. A trend (chi2=4.1; p=0.12) to the prevalence of individuals with SS genotype (21.8%), as compared to expected level (14.6%), was found in the group of octogenarians (n=55, mean age 82.8+/-1.9 years). An association analysis between genotype and physiological traits revealed a genotype contribution to past smoking on tendency level (p=0.069), waist to hip ratio (WHR) (p=0.012) and plasma insulin concentration (p=0.02), with a higher frequency of SS genotype among non-smokers and subjects with lower WHR and insulin concentration. Genotype effect on the traits was stronger, being considered in interaction with the age above 80 years. Genotype was not associated with cognitive functioning (MMSE), but proved to be a significant predictor of MMSE performance (p=0.03) in octogenarians. The results obtained are in line with current concepts of serotonin role in smoking, obesity and cognitive functioning.

New age patterns of survival improvement in Sweden: do they characterize changes in individual aging?

The parameters of the Gompertz approximation to the mortality curve are negatively correlated. Strehler and Mildvan [Science 132 (1960) 14] predicted this property of the mortality curve using a mathematical model of mortality and aging and then confirmed it in empirical studies. Despite the fact that their theory was based on the cohort model of mortality the SM correlation was also revealed in the analysis of period mortality data. In fact, most applications of the SM model to human data use Gompertz's approximation to the period mortality rate. Many researchers studying SM correlation consider it a universal demographic law. Such correlation prescribes a certain regularity in mortality changes. All mortality curves must intersect at one point. Mortality decline must produce the rectangularization of survival curves. In this paper we investigated the changes in the patterns of mortality decline in Sweden between 1861 and 1999. We found a difference in patterns of SM correlation for cohort and period mortality data. We investigated trends in survival improvement and found that the tendency to rectangularization of the survival curve existed for only a limited period of time. Then it was gradually replaced by near parallel shift of the survival curve to the right. We found that the pattern of SM correlation was relatively stable only at certain phases of the survival history of male and female populations. We analyzed past and recent patterns of survival changes and discussed possible causes for instability of SM correlation both in cohort and in period mortality data.

A centenarian-only approach for assessing gene-gene interaction in human longevity

In this study, we introduce a centenarian-only approach to the assessment of gene-gene interaction that contributes to human longevity. This approach corresponds to the non-traditional case-only method in the genetic study of gene and disease associations. We first describe how the method can be implemented to screen for gene-gene interaction in human longevity. Then we apply the method to centenarian data collected from an Italian centenarian study in order to detect the interactions between the REN gene and the mitochondrial haplotypes. A significant interaction between REN gene allele 10 and the mitochondrial H haplotype, which may favour longevity, was found. Important features of the application in human longevity studies are highlighted and discussed. Since centenarians constitute a special population representing successful ageing, the centenarian-only approach will be an important tool in the search for major genes that contribute to human longevity.

The new trends in survival improvement require a revision of traditional gerontological concepts

In 1960, Strehler and Mildvan (SM) theoretically predicted that the parameters of the Gompertz approximation to a mortality curve are negatively correlated. This means that the changes in the human mortality rate resulting from improvement in living standards, progress in health care or the influence of other factors must follow certain regularities prescribed by dependence between the Gompertz parameters. Such dependence, called SM correlation, was then confirmed in a number of empirical studies using period data on human mortality. Since the SM theory was based on the cohort model of mortality, it was tacitly assumed that period and cohort SM correlation patterns are similar. The remarkable stability of the SM correlation pattern revealed in these studies was often regarded as manifestation of a universal demographic law regulating changes in the age pattern of mortality rates. In this paper, we investigated trends in mortality decline in France, Japan, Sweden and the United States. In contrast with traditional expectations, we found that the SM correlation pattern was relatively stable only in certain periods of a population's survival history. Recently, several new correlation patterns emerged and, despite some differences in the timing of the changes, the new patterns are remarkably similar in all four countries. Contrary to traditional expectations, the patterns are not the same for cohort and period mortality data when SM correlations are calculated for France, Sweden and the United States. We show that some changes in the patterns of SM correlation admit interpretation in terms of a biological mechanism of individual adaptation (survival trade off). Some other patterns, however, contradict basic postulates of the SM theory. This indicates the need for revision of traditional concepts establishing the relationship between physiological and demographic patterns of aging.

Have the oldest old adults ever been frail in the past? A hypothesis that explains modern trends in survival

Three important results concerning the shape and the trends of the human mortality rate were discussed recently in demographic and epidemiological literature. These are the deceleration of the mortality rate at old ages, the tendency to rectangularization of the survival curve, and the decline of the old age mortality observed in the second part of the 20th century. In this paper we show that all these results can be explained by using a model with a new type of heterogeneity associated with individual differences in adaptive capacity. We first illustrate the idea of such a model by considering survival in a mixture of two subpopulations of individuals (called "labile" and "stable"). These subpopulations are characterized by different Gompertz mortality patterns, such that their mortality rates cross over. The survival chances of individuals in these subpopulations have different sensitivities to changes in environmental conditions. Then we develop a more comprehensive model in which the mortality rate is related to the adaptive capacity of an organism. We show that the trends in survival patterns experienced by a mixture of such individuals resemble those obtained in an analysis of empirical data on survival in developed countries. Lastly, we present evidence of the existence of subpopulations of phenotypes in both humans and experimental organisms, which were used as prototypes in our models. The existence of such phenotypes provides the possibility that at least part of today's centenarians originated from an initially frail part of the cohort.

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.

How individual age-associated changes may influence human morbidity and mortality patterns

Patterns of human mortality share common traits in different populations. They include higher mortality in early childhood, lower mortality during the reproductive period, an accelerated increase of mortality near the end of the reproductive period, and deceleration in the mortality increase at oldest old ages. The deceleration of mortality rate is one of the most intriguing recent findings in longevity research. The role of differential selection in this phenomenon has been well studied. Possible contribution of individual aging in the shape of mortality curve is also recognized. However, this contribution has not been studied in details. In this paper, we specify most common patterns of age-associated changes in an individual organism and discuss their possible influence on morbidity and mortality in population. We subdivide individual age-associated changes into three components, having different influence on morbidity and mortality: (1) basal, (2) ontogenetic, and (3) time-dependent. Basal changes are connected with the universal decrease in the rate of living during an individual life. As a result, some phenotypic effects of aging may accumulate in an organism at a slower rate with age. Basal changes are likely to contribute to a plateau of morbidity often observed at old ages, and may partially be responsible for mortality deceleration at oldest old ages. Ontogenetic component is connected with change of the stages of ontogenesis (e.g., the growth, the reproductive period and the climacteric) during an individual life. The ontogenesis-related changes contribute to wave-like patterns of morbidity in population and may partially be responsible for mortality increase at middle ages and its deceleration at old ages. Time-dependent changes are connected with long-time exposure of an organism to different harmful factors. They are most likely to contribute to morbidity and mortality acceleration. We discuss how all three components of individual age-associated changes may interact in human organism and influence patterns of morbidity and mortality in population.

[Analysis of genetic heterogeneity of bronchial asthma in relation with the age at the onset of disease]

Earlier, the distribution of bronchial asthma (BA) morbidity with respect to the age of onset (AO) in the Moscow population was found to be bimodal. The distribution had two peaks (before and after 25 years of age) and a significant (P < 0.001) minimum between them. Based on these data, genetic heterogeneity of BA with respect to AO was hypothesized. The purpose of this study was to test this hypothesis via analysis of BA morbidity in families of probands with different AOs. The BA morbidity at different ages and the total recurrent risk of BA were estimated in 1518 relatives of 815 BA probands registered in several district outpatient clinics of Moscow. Based on the data obtained, phenotypic between relatives and correlation by genotype between early-onset and late-onset BA cases (with AOs under and over 25 years, respectively) were estimated. It was demonstrated for the first time that the age distribution of BA morbidity in families of probands was also bimodal. Moreover, when probands with early and late AOs were analyzed separately, proband relatives in each of the two groups exhibited these two peaks of morbidity. This suggests that BA that begins in adolescence and BA of adults are not genetically independent forms of the disease. This agrees with the data on the correlation by genotype between the "forms" with the early and late AOs, which does not significantly differ from 1. However, the prevalence of BA was higher in relatives of those probands who developed BA under the age of 25 compared to relatives of those who developed BA over the age of 25 (11.28 and 7.31%, respectively; P < 0.05). Therefore, patients with early-onset BA are more "burdened" genetically with respect to this disease. Since the BA genetic heterogeneity connected with AO has not been confirmed in this study, it is assumed that the observed bimodal distribution of BA morbidity with respect to age is accounted for by the effect of age itself. In other words, it is hypothesized that ontogenetic factors affect susceptibility to BA so that the susceptibility threshold varies with age.

[Computer programs SAN and EPID: family analysis and epidemiology of multifactorial diseases]

SAN software, a database management system, is elaborated. It is subject-oriented to family analysis in the genetics of multifactorial traits (diseases). The software allows creating and maintaining a family-oriented database and using the inputted information to calculate relative risk of disease, heritability, and correlations between several diseases or forms, with both actual frequency of the trait (prevalence) and probability of new cases (incidence). If appropriate data on sibships or nuclear families are available, one can calculate an empirical estimation of the risk of repeated cases of the disease in a family in relation to family anamnesis in different methods of sampling, sex-related morbidity, and varying age of onset. The database may also be used independently as a card index. The software allows one to represent pedigrees graphically, highlighting the desired set of traits. As application program, EPID, was developed, aimed at calculation and graphical presentation of age-related estimations of prevalence and incidence, as well as of the population risk of an individual to develop a disease within a time interval from birth to a certain age (accumulated morbidity).