Saturday, 2 November 2013



“We are all amateurs; we don’t live long enough to become anything else.”
                                                                                 Charlie Chaplin
Significance of Human Aging
l  People live longer now than ever before
l  By 2030, 20% of the US population will be 65 and older
l  Significant challenge to medicine - ethical, financial, etc.
l  What is “normal” in the aging process - primary aging
l  More susceptibility to disease - secondary aging
l  More heterogeneity in the elderly population
l  Onset indeterminable and progression varied
l  Genetic and environmental factors
Gender is a significant factor
l  Lifestyle a primary factor
l  Various theories of aging attempt to explain the process - bottom line, there is disruption of homeostasis
                                            STAGES OF LIFE
l  Adulthood is attainment of physiologically optimal integrated function
l  Function in adulthood is the standard measure
l  Unsound and incorrect to state that changes with aging are necessarily “abnormal”
l  Three observations of the elderly:
      Greater heterogeneity in responses
      Changes in function do not occur simultaneously
      Changes in function do not occur to the same degree
l  Old age should not be viewed as a “disease” nor should a time clock be put on aging
                                     Human Longevity
l  Significant increase in longevity over past centuries
l  Due to decline in deaths resulting from infectious disease along with improved public health
l  Heart disease, cancer and stroke now most common cause of death
l  Death rates have actually declined in the elderly
l  Is there a limit to human life span and should we prolong life at the expense of overall health?
l  We should be talking in the context of “health span” not life span
Successful Aging
l  Chronologic age and physiologic age not the same
l  Due to complex interactions of genetics and environment
l  Individuals “age” at different rates and there is significant variability
l  Prevalence of disease increases with age
l  Proposed pathways of aging:
l  Aging with disease and disability
l  Usual aging; absence of pathology but presence of decline in function
l  Healthy aging; no pathology or functional loss
l  Pathway goals:
l  De-emphasize aging characterized by decline
l  Emphasize heterogeneity among elderly
l  Underscore positive pathway of aging
l  Highlights possible avoidance of disease associated with aging
l  Heterogeneity of various values and functions
l Many associated with physical inactivity
l Recent research:
     Elderly individuals with weak muscles are at greater risk for mortality than age-matched individuals
     Increase in amount and rate of loss of muscle increases risk of premature death
     Physical inactivity is 3rd leading cause of death in US and plays role in chronic illnesses of  DISEASES          Aging and Disease
Aging is associated with increase in incidence and severity of disease Factors predispose individuals to functional losses later in life
Cell Senescence and Death
l Cell senescence much like apoptosis
      Occurs throughout life
      Arresting growth of damaged/dysfunctional cells
      Beneficial early in life; may contribute to aging later
      Inducers can cause cancer
      Senescence allows cells to respond to inducers, but cells withdraw from growth cycle - incapable of tumorigenesis
      Contribution of cell senescence to aging:
      Altered secretions of cells
      Proteases, inflammatory cytokines, growth factors
      Erosion of structure and integrity of tissues
Current Areas of Research
l Caloric Restriction
l Altered dietary intake
l Insulin-like growth factor (IGF)
l Pharmaceuticals
l Most, if not all, of these have a similar goal of targeting reactive oxygen species, underscoring what appears to be a substantial role of oxidants in the aging process