Show Notes for Episode Twenty-Six of seX & whY: Sex and Gender Differences in Aging Host: Jeannette Wolfe Guest: Sara Haag Dr Haag is a researcher in molecular epidemiology who studies human biological aging at the Karolinska Institute in Stockholm. Background - Dr Haag has a PhD in functional genomics and Post Doc in genetic and molecular epidemiology. She studies telomeres and molecular association with telomere length, she also has experience in molecular biology and computer science. Definitions and discussion points from podcast Geroscience - a new field of biomedical science that looks at how the molecular, genetic, and cellular mechanisms associated with the aging process itself may interact and even trigger many diseases associated with aging. This research provides a different angle for potential intervention to enhance health and longevity.  Life Span - time between birth and death. Heath Span - time within life span of good health. Frailty Index and Clinical Frailty Scale are tools that evaluate a patient’s overall physical conditioning and their vulnerability to certain adverse outcomes including falls, increased care requirements, hospital admission,  and mortality.  Epigenetics - the study of how DNA expression can be modified by behavior or environmental factors (versus alteration in the actual DNA itself). One way I think of this is to imagine a huge library full of books, and that each book represents a gene coded from our DNA- epigenetics help determine which books get pulled off the shelfs and get read or pushed back deeper into the shelfs.  This process is different than buying new books for the library (which would be equivalent to changing the DNA itself.)  Aging Scales - as different elements of the body age differently, there is not a gold standard to measure aging. Dr Haag recently published a study that evaluated a bunch of these different scales and determined that the “ideal” scale will vary dependent upon what you are studying- such as overall function or the biological aging of a specific organ (i.e. heart or liver).   Two major theories of aging: Senescence theory of aging - the belief that with age, cellular systems due to repeat exposure to intracellular and extracellular stressors, eventually start to malfunction and breakdown.  Things start slowly falling apart due to wear and tear.  Programmed theory of aging - Aging is an innate active process which is highly regulated by an internal time clock.  As the field of Geroscience and epigenetics evolves, the “truth” around aging is likely to be a combo of both theories.  Sex Differences Hormones Estrogen Dr Haag talked about research involving telomere length (telomeres are the cap of the chromosome and they help protect the chromosomes from damage.) Typically, telomeres shorten with repeated division in somatic cells and when they shrink to a certain length the cell is more vulnerable to error and damage. Females have longer telomere length at birth compared to males and there is evidence that women with longer exposure to estrogen have longer telomeres.                    Testosterone Here is the Korean Eunuch study mentioned in the podcast.  The researchers examined a genealogical record of 385 eunuchs and compared their life span to several other groups of men who lived during the same time periods including a bunch of kings. They found that the average life span of a eunuch was 70 which was 15-19 years longer than the comparison groups. One theory behind this difference in longevity is “the disposable soma theory”. This postulates that in males there is competition between two different intrinsic systems - somatic aging and reproduction- and that as both systems require significant energy to maintain,  when energy is diverted to one system the other suffers.   Sex Chromosomes In females each cell has two X chromosomes. In female cells, one of the X chromosome