Rejuvenation (aging) 2940858 224486398 2008-07-09T01:44:37Z Davidfuchs42 6755949 /* Basically it doesnt jive with the facts, what is being quoted below should be under healthful living , whats next cellular cross linkages... please!! so 1940's ps I verified hayflicks work*/ '''Rejuvenation''' is the procedure of reversing the [[Senescence|aging process]], thus regaining youth. As people get older, their health worsens, strength and intelligence are thought to diminish, beauty is thought by many to go away. Historically, people in all societies have looked for a way to regain the qualities of youth. In the future however, rejuvenation may become reality through [[stem cell]]s, [[biochemistry|biochemical]] repair and/or [[nanotechnology]]. ==Historical and Cultural Background== {{Refimprove|date=July 2007}} Various myths tell the stories about the quest for rejuvenation. It was believed that [[magic (paranormal)|magic]] or intervention of a [[supernatural]] power can bring back the youth and many mythical adventurers set out on a journey to do that, for themselves, their relatives or some authority that sent them. An ancient Chinese emperor actually sent out ships of young men and women to find a pearl that would rejuvenate him. This led to a myth among modern Chinese that Japan was founded by these people. In some religions people were to be rejuvenated after death prior to placing them in [[heaven]]. The stories continued well into the 16th century. A famous Spanish explorer [[Juan Ponce de León]] led the expedition around the [[Caribbean islands]] and into [[Florida]] to find the [[Fountain of Youth]]. Led by the rumours, the expedition continued the search and many perished. The Fountain was nowhere to be found as locals were unaware of its exact location. Since the emergence of [[philosophy]], [[Wise Old Man|sage]]s and self-proclaimed [[Wizard (fantasy)|wizard]]s always made enormous efforts to find the secret of youth, both for themselves and for their noble [[patron]]s and [[sponsor]]s. It was widely believed that some [[potion]]s may restore the youth. Another commonly cited approach was attempting to transfer the [[essence]] of youth from young people to old. Some examples of this approach were sleeping with [[virgin]]s or [[child]]ren (sometimes literally sleeping, not necessarily having sex)<ref>[http://www.bmj.com/cgi/reprint/321/7276/1580.pdf Steven Shapin and Christopher Martyn, “How to live forever: lessons of history”, [[British Medical Journal]], BMJ 2000;321;1580-1582]</ref>, bathing in or drinking their blood. The quest for rejuvenation reached its height with [[Alchemy]]. All around the Europe and also beyond alchemists were looking for the [[Philosopher's Stone]], the mythical substance that, as it was believed, could not only turn lead into gold, but also prolong life and restore youth. Although the set goal was not achieved, Alchemy paved the way to the [[scientific method]] and so to the medical advances of today. In fiction, there is an increasing amount of work being done on possibilities of rejuvenation treatments, and the effect this would have on society. [[Misspent Youth]] as well as the [[Commonwealth Saga]] by [[Peter F. Hamilton]] are one of the most well known examples of this, dealing with the short and long term effects of a near perfect 80 year old to 20 year old body change with mind intact. Also the [[Mars trilogy]] deals with a much more imperfect type of rejuvenation, including problems such as long term memory loss and sheer boredom that comes with such age. Also the [[post mortal]] characters in the [[Revelation Space]] series often illustrate this issue with long term or essentially infinite lifespans, sheer boredom induces them to undertake activities of extreme risk. ==Modern developments== According to modern science, there are no natural laws preventing successful rejuvenation. In 1965 [[Leonard_Hayflick]] discovered that cells had a finite lifespan, based on the number of doublings the cells underwent. This is called the [[Hayflick_Limit]]. Human cells undergo 50 doublings before cellular [[Senescence]] occurs, mice 20+- doublings, monkeys 30+- doublings. The life span is based in the number of doublings. Hayflicks limit begins at conception and shortens with each cell doubling. [[in_vitro]] and [[in_vivo]] different animals have different life spans based on how often their cells can divide, and how old the donor was when the cell sample was taken. It has been show experimentally that [[in_vitro]] [[telomerase]] can extend the [[telomeres]] indefinitely. (the rest of this article needs to be reworked) [[Ageing|Aging]] is an accumulation of damage to [[macromolecule]]s, [[cell (biology)|cells]], [[biological tissue|tissues]] and [[organ (anatomy)|organs]]. If any of that damage can be repaired, the result is rejuvenation. There have been many experiments which have been shown to increase the [[maximum life span]] of [[laboratory]] animals, thereby achieving [[life extension]]. A few experimental methods such as replacing [[hormone]]s to youthful levels have had considerable success in partially rejuvenating [[laboratory]] animals and humans. There are at least eight important hormones that decline with age: 1. [[human growth hormone]] (HGH); 2. the sexual hormones: testosterone or estrogen/progesterone; 3. erithropoietin [[EPO]]; 4. insulin; 5. DHEA; 6. melatonin; 7. thyroid; 8. pregnenolone. In theory, if all or some of these hormones are replaced, the body will respond to them as it did when it was younger, thus repairing and restoring many body functions. This seems to be borne out in hundreds of thousands of persons who have replaced hormones for many years, especially human growth hormone (HGH, a.k.a. GH). Most attempts at [[genetics|genetic]] repair have traditionally involved the use of a [[retrovirus]] to insert a new [[gene]] into a random position on a [[chromosome]]. But by attaching [[zinc finger]]s (which determine where [[transcription factor]]s bind) to [[endonuclease]]s (which break [[DNA]] strands) [[homologous recombination]] can be induced to correct and replace defective (or undesired) DNA sequences. The first applications of this technology are to isolate [[stem cell]]s from the [[bone marrow]] of patients having [[blood]] disease [[mutation]]s, to correct those mutations in [[Petri dish|laboratory dishes]] using zinc finger endonucleases and to transplant the stem cells back into the patients <ref>{{cite journal | author=Jocelyn Kaiser | title=Gene therapy. Putting the fingers on gene repair | journal=[[Science (journal)|SCIENCE]] | volume=310 | issue=5756 | year=2005 | pages=1894–1896 | pmid=16373552 | doi=10.1126/science.310.5756.1894 }}</ref>. [[Regeneration (biology)|Regenerative]] medicine uses three different strategies: #Implantation of [[stem cell]]s from [[cell culture|culture]] into an existing [[Biological tissue|tissue]] structure #Implantation of stem cells into a tissue [[scaffolding|scaffold]] that guides restoration or #Induction of residual [[Cell (biology)|cells]] of a tissue structure to regenerate the necessary [[body]] part. A [[salamander]] can not only regenerate a [[Limb (anatomy)|limb]], but can regenerate the [[Lens (anatomy)|lens]] or [[retina]] of an [[eye]] and can regenerate an [[intestine]]. For regeneration the salamander tissues form a [[blastema]] by [[Cellular differentiation|de-differentiation]] of [[Mesenchymal stem cell|mesenchymal cells]], and the [[blastema]] functions as a self-organizing system to regenerate the limb <ref>{{cite journal | author=Brockes JP, Kumar A | title=Appendage regeneration in adult vertebrates and implications for regenerative medicine | journal=[[Science (journal)|SCIENCE]] | volume=310 | issue=5756 | year=2005 | pages=1919–1923 | pmid=16373567 | doi=10.1126/science.1115200 }}</ref>. Yet another option involves cosmetic changes to the individual to create the appearance of youth. These are generally superficial and do little to make the person healthier or live longer, but the real improvement in a person's appearance may elevate their mood and have positive side effects normally correlated with [[happiness]]. [[Cosmetic surgery]] is a large industry offering treatments such as removal of wrinkles ("face lift"), removal of extra fat (liposuction) and reshaping or augmentation of various body parts ([[abdomen]], [[breast]]s, [[face]]). There are also, as always in history, many fake rejuvenation products that do not work. Chief among these are powders and sprays and gels and homeopathic that claim to be "growth hormone". Authentic growth hormone can only be injected, because the 191 amino-acid protein is too large to be absorbed through the mucous membranes, and would break up in the stomach if it is swallowed. ==Strategies for Engineered Negligible Senescence (SENS)== {{main|Strategies for Engineered Negligible Senescence}} The leading modern exponent of scientific rejuvenation is the biomedical [[gerontology|gerontologist]] Dr.&nbsp;[[Aubrey de Grey]]. He calls his project to reverse the damage we call ''aging'' "SENS" (Strategies for Engineered Negligible Senescence). He has proposed seven strategies for what he calls the "seven deadly sins": # Cell loss can be repaired (reversed) just by suitable [[exercise]] in the case of [[muscle]]. For other tissues it needs various [[growth factor]]s to stimulate [[cell division]], or in some cases it needs [[stem cells]]. # Senescent [[cell (biology)|cells]], can be removed by activating the [[immune system]] against them. Or they can be destroyed by [[gene therapy]] to introduce "suicide [[gene]]s" that only kill senescent cells. # [[Protein]] [[cross-linking]] can largely be reversed by [[medication|drugs]] that break the links. But to break some of the cross-links we may need to develop enzymatic methods. # [[Extracellular]] garbage (like [[amyloid]]) can be eliminated by [[vaccination]] that gets [[immune]] cells to "eat" the garbage. # For intracellular junk we need to introduce new [[enzyme]]s, possibly enzymes from soil [[bacteria]], that can degrade the junk ([[lipofuscin]]) that our own natural enzymes cannot degrade. # For [[mitochondrion|mitochondrial]] mutations the plan is not to repair them but to prevent harm from the mutations by putting suitably modified copies of the mitochondrial genes into the [[cell nucleus]] by gene therapy. The [[mitochondrial DNA]] experiences a high degree of [[mutagenic]] damage because most [[radical (chemistry)|free radicals]] are generated in the [[mitochondria]]. A copy of the mitochondrial DNA located in the [[cell nucleus|nucleus]] will be better protected from free radicals, and there will be better [[DNA repair]] when damage occurs. All mitochondrial [[protein]]s would then be imported into the mitochondria. # For [[cancer]] (the most lethal consequence of mutations) the strategy is to use [[gene therapy]] to delete the [[gene]]s for [[telomerase]] and to eliminate telomerase-independent mechanisms of turning normal cells into "immortal" cancer cells. To compensate for the loss of telomerase in [[stem cells]] we would introduce new stem cells every decade or so. Dr. de Grey has created the [[Methuselah Mouse Prize]], which awards money to researchers who can rejuvenate [[mouse|mice]]. ==Scientific Journal== * ''[[Rejuvenation Research]]'' Editor: [[Aubrey de Grey]]. Publisher: [[Mary Ann Liebert, Inc.]] ISSN 1549-1684 - Published Quarterly. ==See also== <div class="references" style="-moz-column-count:3; column-count:3;"> * [[American Academy of Anti-Aging Medicine]] * [[Gerontology#Biogerontology|Biogerontology]] * [[Biological immortality]] * [[DNA repair]] * [[DNA damage theory of aging]] * [[Facial rejuvenation]] * [[Fountain of Youth]] * [[Hayflick]] * [[Hayflick_Limit]] * [[Immortality]] * [[Indefinite lifespan]] * [[Life extension]] * [[Nanomedicine]] * [[SAGE KE]] * [[Senescence]] * [[Shunamitism]] * [[Telomere]] * [[Telomerase]] * [[Tissue engineering]] * [[Therapeutic cloning]] </div> ==References== <references/> ==External links== ===Strategies for Engineered Negligible Senescence=== * [http://www.sens.org/ Strategies for Engineered Negligible Senescence (SENS)] ===Other=== * [http://www.worldhealth.net/ American Academy of Anti-Aging Medicine] * [http://www.benbest.com/lifeext/aging.html#rejuvenate Regenerative Medicine and Rejuvenation] * [http://www.lef.org/magazine/mag2006/feb2006_profile_01.htm Life Extension magazine interview about rejuvenation science] * [http://www.biologicalgerontology.com Resources and Articles on the Biology of Aging and Life-Extension] [[Category:Aging]] [[Category:Gerontology]] [[Category:Life extension| ]] [[Category:Transhumanism]] [[Category:Demography]] [[ru:Омоложение]] [[zh:回復青春]]