Editing Life extension (section)

==Research==
Theoretically, extension of maximum lifespan in humans could be achieved by reducing the rate of aging damage by [[tissue engineering|periodic replacement of damaged tissues]], [[nanobiotechnology|molecular repair]] or [[rejuvenation (aging)|rejuvenation]] of deteriorated cells and tissues, reversal of harmful epigenetic changes, or the enhancement of enzyme [[telomerase]] activity.<ref>{{cite journal | vauthors = Rando TA, Chang HY | title = Aging, rejuvenation, and epigenetic reprogramming: resetting the aging clock | journal = Cell | volume = 148 | issue = 1–2 | pages = 46–57 | date = January 2012 | pmid = 22265401 | pmc = 3336960 | doi = 10.1016/j.cell.2012.01.003 | author-link2 = Howard Y. Chang }}</ref><ref>{{cite journal | vauthors = Johnson AA, Akman K, Calimport SR, Wuttke D, Stolzing A, de Magalhães JP | title = The role of DNA methylation in aging, rejuvenation, and age-related disease | journal = Rejuvenation Research | volume = 15 | issue = 5 | pages = 483–494 | date = October 2012 | pmid = 23098078 | pmc = 3482848 | doi = 10.1089/rej.2012.1324 }}</ref>

Research geared towards life extension strategies in various organisms is currently under way at a number of academic and private institutions. Since 2009, investigators have found ways to increase the lifespan of nematode worms and yeast by 10-fold; the record in nematodes was achieved through [[genetic engineering]] and the extension in yeast by a combination of genetic engineering and [[caloric restriction]].<ref name=Shmookle>{{cite journal | vauthors = Shmookler Reis RJ, Bharill P, Tazearslan C, Ayyadevara S | title = Extreme-longevity mutations orchestrate silencing of multiple signaling pathways | journal = Biochimica et Biophysica Acta (BBA) - General Subjects | volume = 1790 | issue = 10 | pages = 1075–1083 | date = October 2009 | pmid = 19465083 | pmc = 2885961 | doi = 10.1016/j.bbagen.2009.05.011 }}</ref> A 2009 review of longevity research noted: "Extrapolation from worms to mammals is risky at best, and it cannot be assumed that interventions will result in comparable life extension factors. Longevity gains from dietary restriction, or from mutations studied previously, yield smaller benefits to Drosophila than to nematodes, and smaller still to mammals. This is not unexpected, since mammals have evolved to live many times the worm's lifespan, and humans live nearly twice as long as the next longest-lived primate. From an evolutionary perspective, mammals and their ancestors have already undergone several hundred million years of natural selection favoring traits that could directly or indirectly favor increased longevity, and may thus have already settled on gene sequences that promote lifespan. Moreover, the very notion of a "life-extension factor" that could apply across taxa presumes a linear response rarely seen in biology."<ref name=Shmookle/>

=== Anti-aging drugs ===

There are numerous chemicals intended to slow the aging process under study in [[animal model]]s.<ref>{{cite journal | vauthors = Childs BG, Durik M, Baker DJ, van Deursen JM | title = Cellular senescence in aging and age-related disease: from mechanisms to therapy | journal = Nature Medicine | volume = 21 | issue = 12 | pages = 1424–1435 | date = December 2015 | pmid = 26646499 | pmc = 4748967 | doi = 10.1038/nm.4000 }}</ref> One type of research is related to the observed effects of a [[calorie restriction]] (CR) diet, which has been shown to extend lifespan in some animals.<ref>{{cite journal | vauthors = Anderson RM, Shanmuganayagam D, Weindruch R | title = Caloric restriction and aging: studies in mice and monkeys | journal = Toxicologic Pathology | volume = 37 | issue = 1 | pages = 47–51 | date = January 2009 | pmid = 19075044 | pmc = 3734859 | doi = 10.1177/0192623308329476 }}</ref> Based on that research, there have been attempts to develop drugs that will have the same effect on the aging process as a CR diet, which are known as [[caloric restriction mimetic]] drugs, such as [[rapamycin]]<ref>{{cite journal | vauthors = Harrison DE, Strong R, Sharp ZD, Nelson JF, Astle CM, Flurkey K, Nadon NL, Wilkinson JE, Frenkel K, Carter CS, Pahor M, Javors MA, Fernandez E, Miller RA | display-authors = 6 | title = Rapamycin fed late in life extends lifespan in genetically heterogeneous mice | journal = Nature | volume = 460 | issue = 7253 | pages = 392–395 | date = July 2009 | pmid = 19587680 | pmc = 2786175 | doi = 10.1038/nature08221 | bibcode = 2009Natur.460..392H }}</ref> and [[metformin]].<ref>{{cite journal | vauthors = Dhahbi JM, Mote PL, Fahy GM, Spindler SR | title = Identification of potential caloric restriction mimetics by microarray profiling | journal = Physiological Genomics | volume = 23 | issue = 3 | pages = 343–350 | date = November 2005 | pmid = 16189280 | doi = 10.1152/physiolgenomics.00069.2005 | citeseerx = 10.1.1.327.4892 }}</ref>

[[Sirtuin]] activating [[polyphenol]]s, such as [[resveratrol]] and [[pterostilbene]],<ref>{{cite journal | vauthors = Kaeberlein M | title = Resveratrol and rapamycin: are they anti-aging drugs? | journal = BioEssays | volume = 32 | issue = 2 | pages = 96–99 | date = February 2010 | pmid = 20091754 | doi = 10.1002/bies.200900171 | s2cid = 16882387 }}</ref><ref>{{cite journal | vauthors = Barger JL, Kayo T, Vann JM, Arias EB, Wang J, Hacker TA, Wang Y, Raederstorff D, Morrow JD, Leeuwenburgh C, Allison DB, Saupe KW, Cartee GD, Weindruch R, Prolla TA | display-authors = 6 | title = A low dose of dietary resveratrol partially mimics caloric restriction and retards aging parameters in mice | journal = PLOS ONE | volume = 3 | issue = 6 | pages = e2264 | date = June 2008 | pmid = 18523577 | pmc = 2386967 | doi = 10.1371/journal.pone.0002264 | bibcode = 2008PLoSO...3.2264B | doi-access = free }}</ref><ref>{{cite journal | vauthors = McCormack D, McFadden D | title = A review of pterostilbene antioxidant activity and disease modification | journal = Oxidative Medicine and Cellular Longevity | volume = 2013 | pages = 575482 | year = 2013 | pmid = 23691264 | pmc = 3649683 | doi = 10.1155/2013/575482 | doi-access = free }}</ref> and [[flavonoid]]s, such as [[quercetin]] and [[fisetin]],<ref name="Martel-2020">{{cite journal | vauthors = Martel J, Ojcius DM, Wu CY, Peng HH, Voisin L, Perfettini JL, Ko YF, Young JD | display-authors = 6 | title = Emerging use of senolytics and senomorphics against aging and chronic diseases | journal = Medicinal Research Reviews | volume = 40 | issue = 6 | pages = 2114–2131 | date = November 2020 | pmid = 32578904 | doi = 10.1002/med.21702 | s2cid = 220047655 }}</ref> as well as [[oleic acid]]<ref>{{cite journal | vauthors = Mutlu AS, Duffy J, Wang MC | title = Lipid metabolism and lipid signals in aging and longevity | journal = Developmental Cell | volume = 56 | issue = 10 | pages = 1394–1407 | date = May 2021 | pmid = 33891896 | pmc = 8173711 | doi = 10.1016/j.devcel.2021.03.034 }}</ref> are [[dietary supplement]]s that have also been studied in this context. Other common supplements with less clear biological pathways to target aging include [[lipoic acid]],<ref>{{cite journal | vauthors = Shay KP, Moreau RF, Smith EJ, Smith AR, Hagen TM | title = Alpha-lipoic acid as a dietary supplement: molecular mechanisms and therapeutic potential | journal = Biochimica et Biophysica Acta (BBA) - General Subjects | volume = 1790 | issue = 10 | pages = 1149–1160 | date = October 2009 | pmid = 19664690 | pmc = 2756298 | doi = 10.1016/j.bbagen.2009.07.026 }}</ref> [[senolytic]]s,<ref name="Martel-2020" /> and [[coenzyme Q10]].<ref>{{cite journal | vauthors = Arenas-Jal M, Suñé-Negre JM, García-Montoya E | title = Coenzyme Q10 supplementation: Efficacy, safety, and formulation challenges | journal = Comprehensive Reviews in Food Science and Food Safety | volume = 19 | issue = 2 | pages = 574–594 | date = March 2020 | pmid = 33325173 | doi = 10.1111/1541-4337.12539 | doi-access = free | hdl = 2445/181270 | hdl-access = free }}</ref> 

While agents such as these have some limited laboratory evidence of efficacy in animals, there are no studies to date in humans for drugs that may promote life extension, mainly because research investment remains at a low level, and regulatory standards are high.<ref name="aarp">{{cite web |first1=Rachel|last1=Nania |title=A pill to slow aging? |url=https://www.aarp.org/health/drugs-supplements/info-2023/pill-to-slow-aging.html |publisher=AARP |access-date=7 September 2024 |date=15 November 2023}}</ref> Aging is not recognized as a preventable condition by governments, indicating there is no clear pathway to approval of anti-aging medications.<ref name=aarp/> Further, anti-aging drug candidates are under constant review by regulatory authorities like the US [[Food and Drug Administration]], which stated in 2023 that "no medication has been proven to slow or reverse the aging process."<ref name="fda-fraud">{{cite web |title=Medication Health Fraud for Specific Diseases and Conditions |url=https://www.fda.gov/drugs/medication-health-fraud/medication-health-fraud-specific-diseases-and-conditions |archive-url=https://web.archive.org/web/20230825214009/https://www.fda.gov/drugs/medication-health-fraud/medication-health-fraud-specific-diseases-and-conditions |url-status=dead |archive-date=25 August 2023 |publisher=US Food and Drug Administration |access-date=7 September 2024 |date=9 August 2023}}</ref>

=== Nanotechnology ===
Future advances in [[nanomedicine]] could give rise to life extension through the repair of many processes thought to be responsible for aging. [[K. Eric Drexler]], one of the founders of [[nanotechnology]], postulated [[Cell (biology)|cell]] repair machines, including ones operating within cells and utilizing as yet hypothetical molecular [[computers]], in his 1986 book ''[[Engines of Creation]]''. [[Raymond Kurzweil]], a [[futurist]] and [[transhumanist]], stated in his book ''[[The Singularity Is Near]]'' that he believes that advanced medical [[nanorobotics]] could completely remedy the effects of aging by 2030.<ref>{{Cite book | vauthors = Kurzweil R |author-link=Raymond Kurzweil |year=2005 |title=The Singularity Is Near |publisher=[[Viking Press]] |location=[[New York City]] |isbn=978-0-670-03384-3 |oclc=57201348|title-link=The Singularity Is Near }}{{Page needed|date=September 2010}}</ref> According to [[Richard Feynman]], it was his former graduate student and collaborator [[Albert Hibbs]] who originally suggested to him (circa 1959) the idea of a ''medical'' use for Feynman's theoretical [[nanomachines]] (see [[biological machine]]). Hibbs suggested that certain repair machines might one day be reduced in size to the point that it would, in theory, be possible to (as Feynman put it) "[[Molecular machine#Biological|swallow the doctor]]". The idea was incorporated into Feynman's 1959 essay ''[[There's Plenty of Room at the Bottom]].''<ref>{{cite web |url = http://www.its.caltech.edu/~feynman/plenty.html|title = There's Plenty of Room at the Bottom| vauthors = Feynman RP |date = December 1959 |access-date   = 22 March 2016 |archive-url  = https://web.archive.org/web/20100211190050/http://www.its.caltech.edu/~feynman/plenty.html |archive-date = 2010-02-11 |url-status = dead}}</ref>

=== Cyborgs ===
{{Main|Cyborg}}
Replacement of biological (susceptible to diseases) organs with mechanical ones could extend life. This is the goal of the [[2045 Initiative]].<ref>{{cite web | vauthors = Segal D | work = The New York Times | date = 1 June 2013 | url = https://www.nytimes.com/2013/06/02/business/dmitry-itskov-and-the-avatar-quest.html?pagewanted=all&_r=0 | title = This Man Is Not a Cyborg. Yet. }}</ref>
=== Cryonics ===
{{Main|Cryonics}}
Cryonics is the [[Cryopreservation|low-temperature freezing]] (usually at {{cvt|−196|C|F K|disp=or}}) of a human corpse, with the hope that [[wikt:resuscitate|resuscitation]] may be possible in the [[future]].<ref>{{cite news| vauthors = McKie R |title=Cold facts about cryonics|url=https://www.theguardian.com/education/2002/jul/14/medicalscience.science|access-date=1 December 2013|newspaper=[[The Observer]]|date=13 July 2002|quote=Cryonics, which began in the Sixties, is the freezing – usually in liquid nitrogen – of human beings who have been legally declared dead. The aim of this process is to keep such individuals in a state of refrigerated limbo so that it may become possible in the [[future]] to resuscitate them, cure them of the condition that killed them, and then restore them to functioning life in an era when medical science has triumphed over the activities of the Grim Reaper.
}}</ref><ref>{{cite news | vauthors = Day E |title=Dying is the last thing anyone wants to do – so keep cool and carry on|url=https://www.theguardian.com/science/2015/oct/11/cryonics-booms-in-us|access-date=21 February 2016|work=[[The Guardian]]|date=10 October 2015}}</ref> It is regarded with [[skepticism]] within the mainstream scientific community and has been characterized as [[quackery]].<ref>{{cite book | vauthors = Butler K |title=A Consumer's Guide to "Alternative" Medicine |publisher=Prometheus Books |year=1992 |page=173}}</ref>

=== Strategies for engineered negligible senescence ===
{{Main|Strategies for engineered negligible senescence|Genetics of aging}}
Another proposed life extension technology aims to combine existing and predicted future biochemical and genetic techniques. SENS proposes that rejuvenation may be obtained by removing aging damage via the use of [[stem cell]]s and [[tissue engineering]], [[telomere]]-lengthening machinery, [[allotopic expression]] of [[mitochondrial]] proteins, targeted ablation of cells, [[immunotherapy|immunotherapeutic]] clearance, and novel [[lysosome|lysosomal]] [[hydrolases]].<ref>{{Cite book | vauthors = de Grey A, Rae M  |author-link=Aubrey de Grey | title=Ending Aging: The Rejuvenation Breakthroughs that Could Reverse Human Aging in Our Lifetime |publisher=[[St. Martin's Press]] |year=2007 |location=[[New York City]] |isbn= 978-0-312-36706-0 |oclc=132583222|title-link=Ending Aging }}{{Page needed|date=September 2010}}</ref>

While some [[Biogerontology|biogerontologists]] find these ideas "worthy of discussion",<ref>{{cite web | vauthors = Pontin J | date = 11 July 2006 | url = http://www.technologyreview.com/sens/ | title = Is Defeating Aging Only A Dream? | work = Technology Review | access-date = 15 February 2013 | archive-date = 11 September 2012 | archive-url = https://archive.today/20120911155923/http://www.technologyreview.com/sens/ | url-status = dead }}</ref><ref>{{cite news | vauthors = Garreau J | date = 31 October 2007 | url = https://www.washingtonpost.com/wp-dyn/content/article/2007/10/30/AR2007103002222.html?hpid=features1&hpv=national | title = The Invincible Man | newspaper = Washington Post }}</ref> others contend that the alleged benefits are too speculative given the current state of technology, referring to it as "fantasy rather than science".<ref name=Holliday /><ref name="EMBOSENS" />