Physiology of the Aging Process Painting by Domenico Ghirlandaio (Florence ) Spring 2007

Why study aging? 1.Increased length of lifespan & increased number of the elderly in the human population, worldwide 2.Increased proportion of persons aged 65+ in some populations as compared to those aged This greater human longevity is acknowledged by developing technologies, markets and professions 4.Need to better educate the population in healthy habits 5.Need to support research in biomedicine 6.Points 4 and 5 must take into consideration the entire life cycle as our health today depends on our health yesterday and will influence our health tomorrow 1.Increased length of lifespan & increased number of the elderly in the human population, worldwide 2.Increased proportion of persons aged 65+ in some populations as compared to those aged This greater human longevity is acknowledged by developing technologies, markets and professions 4.Need to better educate the population in healthy habits 5.Need to support research in biomedicine 6.Points 4 and 5 must take into consideration the entire life cycle as our health today depends on our health yesterday and will influence our health tomorrow

Age Percent Surviving Source: Arias E. United States Life Tables, National Vital Statistics Reports; vol. 53, no. 6. Hyattsville, MD: National Center for Health Statistics, Survival Curves for U.S. Population, 1900 to 2002

Probability of 50 year old living to 90, 1900 to Percent Men Women 30 Source: Computed from U.S. life tables in: Arias E. United States life tables, National vital statistics reports; vol. 53, no. 6. Hyattsville, MD: National Center for health Statistics, 2004.

Life expectancy and infant mortality throughout human history Life expectancy Infant mortality rate at birth (years) (per 1000 live births) Prehistoric Sweden, 1750s37210 India, 1880s25230 U. S., France, Japan,

According to the renowned economist, Fogel R.W. Fogel “ Health care is the growth industry of the 21st century. It will promote economic growth through its demand for high-tech products, skilled personnel, and new technologies” According to the renowned economist, Fogel R.W. Fogel “ Health care is the growth industry of the 21st century. It will promote economic growth through its demand for high-tech products, skilled personnel, and new technologies”

Stages of the Lifespan Prenatal Life Ovum: Fertilization - end 1st week Embryo: 2nd-8th week Fetus: 3rd-10 lunar month Neonatal Period Newborn: end of 2nd week Infancy: 3rd week-1st year Childhood: 2-15 years Adolescence: 6 yrs after puberty Postnatal Life Adulthood Prime & transition (20-65 yrs) Old age & senescence (65 yrs+) Chapter 1, Table 1.1

The journey of life is NOT a simple juxtaposition of successive functional timetables Rather, physiologic competence at each stage of life: is influenced by the functional events in preceding stages and influences the degree of competence of the stages that follow The genome dictates the genetic characteristic of the species but Genetic expression of each individual within the species may be modified throughout life by the environment

Genome meet your environment! Thus, longevity depends: not only on genetic inheritance but also on gene-environment interactions Longevity is an important decision nature must make Usually important decisions in nature are regulated in a complex way As organisms become more complex so does the need to balance life and death

The genome proposes and the phenome disposes

Increase in longevity over centuries may be related to progress in human civilization as exemplified by progress in physio-technology Caused by improvements in agriculture, economics, public health, hygiene, etc. Resulting in more efficient functional competence: less infant mortality better growth delayed occurrence of aging- related diseases Manipulation of the environment may prolong the lifespan: better nutrition more learning more physical exercise, etc

For the vocabulary of common terms related to aging, see Table 1-2 (Handout)

Methods to Study Physiology of Aging 1.Study in humans a.Cross-sectional methods Compare characteristics among different individuals of the same age at one time. Rapidity but relative accuracy b.Longitudinal studies Examine the same individuals at regular time intervals throughout life (or portion of life). Each person is his/her own control. Accuracy but difficulty of repeatedly reaching the same people. c.Activities of Daily Living (ADL) / Instrumental Activities of Daily Living (IADL) a.Clinical Studies

2.Study in animals (eg. vertebrates, invertebrates, yeast) Comparison of physiological characteristics and longevity among animals. Creation of transgenic mice for expression or deletion (knock-out) of specific traits Methods to Study Physiology of Aging (cont.)

3. In vitro studies (eg. cultured cells, tissues, organs) Methods to Study Physiology of Aging (cont.) Microglia (immune cells) Neuroglia: Astrocytes Neuroglia: Oligodendrocytes