Biological immortality 1231522 225710778 2008-07-15T00:55:38Z Phenylalanine 5382478 fixed wikilinks {{Otheruses4|the scientific aspect of immortality|for other uses|Immortality}} '''[[biology|Biological]] [[immortality]]''' can be defined as the absence of a sustained increase in [[Mortality rate|rate of mortality]] as a function of chronological age. A cell or organism that does not experience, or at some future point will cease [[senescence|aging]], is biologically immortal. However this definition of immortality was challenged in the new "Handbook of the Biology of Aging",<ref> {{cite book | first=E.J. | last=Masoro | coauthors=Austad S.N. (eds.)| year=2006 | title=Handbook of the Biology of Aging | edition=Sixth | publisher=Academic Press | location=San Diego, CA, USA | id=ISBN 0-12-088387-2 }}</ref> because the increase in rate of mortality as a function of chronological age may be negligible at extremely [[old age]]s (late-life mortality plateau). But even though the rate of mortality ceases to increase in old age, those rates are very high<ref>{{cite journal | title = Late life: a new frontier for physiology | author = Michael R. Rose; Casandra L. Rauser; Laurence D. Mueller | journal = Physiological And Biochemical Zoology | year = 2005 | month= Nov-Dec | volume = 78 | number = 6 | pages=869–878 | pmid = 16228927 | doi = 10.1086/498179 }}</ref> (e.g., 50% chance of surviving another year at age 110 or 115 years of age). There is no known [[organism]] or individual [[cell (biology)|cell]] that is inviolably [[immortality|immortal]]. Any life enjoying ''biological immortality'' can die if exposed to a toxic environment, or otherwise [[kill]]ed or destroyed. ==Cell lines== {{main|Cell culture}} [[Biologist]]s have chosen the word immortal to designate cells that are not limited by the [[Hayflick limit]] (where cells no longer divide because of [[DNA repair|DNA damage]] or shortened [[telomere]]s). (Prior to the work of [[Leonard Hayflick]] there was the erroneous belief fostered by [[Alexis Carrel]] that all normal [[somatic]] cells are immortal.) The term immortalization was first applied to [[cancer]] cells that expressed the telomere-lengthening [[enzyme]] [[telomerase]], and thereby avoided [[apoptosis]] (programmed cell death). Among the most commonly used cell lines are [[HeLa]] and [[Jurkat cells|Jurkat]], both of which are immortalized cancer cells. Normal [[stem cell]]s and [[germ cell]]s can also be said to be immortal. Immortal cell lines of cancer cells can be created by induction of [[oncogenes]] or loss of [[tumor suppressor gene|tumor suppressor genes]]. One way to induce immortality is through viral-mediated induction of the [[SV40 Large T-antigen|large T-antigen]],<ref>{{cite journal |title = Expression of the Large T Protein of Polyoma Virus Promotes the Establishment in Culture of "Normal" Rodent Fibroblast Cell Lines |author = Michael R. Rose; Casandra L. Rauser; Laurence D. Mueller |journal = PNAS |year = 1983 |volume = 80 , 4354-4358 }}</ref> commonly introduced through [[SV40|simian virus 40]] (SV-40). In terms of multi-cellular organisms, immortality may not be a desirable condition, as the main controls over cancer are the apoptotic mechanisms<ref>{{cite journal | title = Predominant suppression of apoptosome by inhibitor of apoptosis protein in non-small cell lung cancer H460 cells: therapeutic effect of a novel polyarginine-conjugated Smac peptide | author = Michael R. Rose; Casandra L. Rauser; Laurence D. Mueller | journal = Cancer Res. | month = February | year = 2003 | volume = 63 | number = 19 | pmid = 12591734 }}</ref>. ==Bacteria== [[Bacteria]] can be said to be biologically immortal, but only as a [[colony (biology)|colony]]. An individual bacterium can easily die. The two daughter bacteria resulting from [[cell division]] of a parent bacterium can be regarded as unique individuals or as members of a [[biology|biologically]] "immortal" colony. The two daughter cells can be regarded as "[[rejuvenation (aging)|rejuvenated]]" copies of the parent cell because damaged [[macromolecule]]s have been split between the two cells and diluted. In the same way [[stem cell]]s and [[gamete]]s can be regarded as "immortal". ==Hydra== [[Hydra (genus)|Hydra]]s are a genus of simple, fresh-water animals possessing radial symmetry and no post-mitotic cells. The fact that all cells continually divide allows defects and toxins to be "diluted-away". It has been suggested that hydras do not undergo [[senescence]] (aging), and so are biologically immortal<ref>http://www.ucihs.uci.edu/biochem/steele/PDFs/Hydra_senescence_paper.pdf</ref>. ==Life extensionists== Some [[life extension]]ists, such as those who practice [[cryonics]], have the hope that humans may someday become biologically immortal. This would not be the same as literal [[immortality]], since people can always be murdered or die in accidents. ([[Mind uploading]], however, could allow literal immortality in a sense, by uploading backups into cloned or artificial bodies after an accident. See [[Mind_uploading#Mind_uploading_in_science_fiction|Mind uploading in science fiction]].) [[Nanotechnology]], and specifically of [[nanomedicine]], have recently increased awareness of the possibilities for biological immortality in humans. A study published in Physiological and Biochemical Zoology in 2005 indicates that biological immortality may exist in humans at a late stage in life: "the exponential increase in age-specific death rate seemed to slow down considerably, if not cease."<ref>http://darwin.bio.uci.edu/~mueller/pdf/PBZ%2005.pdf</ref> The [[gerontologist|biogerontologist]] [[Aubrey de Grey]] of [[University of Cambridge|Cambridge University]] has proposed that damage to [[macromolecule]]s, [[cell (biology)|cell]]s, [[biological tissue|tissue]]s and [[organ (anatomy)|organ]]s could be repaired by advanced [[biotechnology]]. He calls his project [[Strategies for Engineered Negligible Senescence|SENS]] (Strategies for Engineered Negligible Senescence). Dr. de Grey has created the [[Methuselah Mouse Prize]] to award money to researchers who can significantly extend the lifespan of, or [[rejuvenation (aging)|rejuvenate]] mice. It is his hope that if a monetary reward is offered, it will increase the likelihood of mice being rendered extremely, unnaturally long-lived by science, and that such a feat will inspire research into replicating this achievement in humans which may spark a "''buy-in''" with many people willing to pay large amounts of money for the benefits of such research. ==See also== *[[DNA damage theory of aging]] *[[Aging Research Centre]] *[[American Academy of Anti-Aging Medicine]] *[[Strategies for Engineered Negligible Senescence]] (SENS) *[[Immortality Institute]] *[[Hayflick limit]] *[[Hydra (genus)|Hydra]] *[[Life extension]] *[[Maximum lifespan]] *[[Methuselah Mouse Prize]] *[[Senescence]] ==References== <references /> * [[James L. Halperin]]. ''The First Immortal'', Del Rey, 1998. ISBN 0-345-42092-6 * [[Robert Ettinger]]. ''The Prospect of Immortality'', Ria University Press, 2005. ISBN 0-9743472-3-X * Dr. R. Michael Perry. ''Forever For All: Moral Philosophy, Cryonics, and the Scientific Prospects for Immortality'', Universal Publishers, 2001. ISBN 1-58112-724-3 * *Martinez, D.E. (1998) "Mortality patterns suggest lack of senescence in hydra." ''Experimental Gerontology'' 1998 May;33(3):217-225. [http://www.ucihs.uci.edu/biochem/steele/PDFs/Hydra_senescence_paper.pdf Full text.] ==External links== * [http://www.benford-rose.com/bioimm-atlanta05.htm Biological Immortality] Slide show by Michael R. Rose * [http://www.benbest.com/lifeext/aging.html#senescence Cellular Senscence and Apoptosis in Aging] *[http://websites.afar.org/site/PageServer?pagename=IA_b_sene_home Cellular Senescence Information Center] * [http://www.genomicsproteomics.com/index.aspx?ID=69329 Geron Announces Launch of Telomerase-Immortalized Cell Line] [[Geron Corporation]] * [http://darwin.bio.uci.edu/~mueller/pdf/PBZ%2005.pdf Late Life: A New Frontier for Physiology] study indicates biological immortality in humans late in life * [http://longevity-science.org/Betterhumans-2004.pdf No Limit to Lifespan if We're Machines] (pdf) - ''Betterhumans'', August 26, 2004 * [http://www.firstimmortal.com/ The First Immortal]: free download * [http://www.cryonics.org/book1.html The Prospect of Immortality]: free download [[Category:Aging]] [[de:Immortalisierung]] [[fi:Biologinen kuolemattomuus]] [[ru:Биологическое бессмертие]]