Rejuvenation is a medical discipline focused on the practical reversal of the aging process. Rejuvenation is distinct from

life extension Life extension is the concept of extending the human lifespan, either modestly through improvements in medicine or dramatically by increasing the maximum lifespan beyond its generally-settled biological limit of around 125 years. Several resea ...

. Life extension strategies often study the causes of

aging Ageing (or aging in American English) is the process of becoming Old age, older until death. The term refers mainly to humans, many other animals, and fungi; whereas for example, bacteria, perennial plants and some simple animals are potentiall ...

and try to oppose those causes to slow aging. Rejuvenation is the ''reversal'' of aging and thus requires a different strategy, namely repair of the

damage Damage is any change in a thing, often a physical object, that degrades it away from its initial state. It can broadly be defined as "changes introduced into a system that adversely affect its current or future performance".Farrar, C.R., Sohn, H., ...

that is associated with aging or replacement of damaged tissue with new tissue. Rejuvenation can be a means of life extension, but most life extension strategies do not involve rejuvenation.

Historical and cultural background

Various myths tell the stories about the quest for rejuvenation. It was believed that magic or intervention of a

supernatural Supernatural phenomena or entities are those beyond the Scientific law, laws of nature. The term is derived from Medieval Latin , from Latin 'above, beyond, outside of' + 'nature'. Although the corollary term "nature" has had multiple meanin ...

power can bring back youth and many mythical adventurers set out on a journey to do that, for themselves, their relatives or some authority that sent them anonymously. An ancient Chinese emperor 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 Heaven, or the Heavens, is a common Religious cosmology, religious cosmological or supernatural place where beings such as deity, deities, angels, souls, saints, or Veneration of the dead, venerated ancestors are said to originate, be throne, ...

. The stories continued well into the 16th century. The Spanish explorer

Juan Ponce de León Juan Ponce de León ( – July 1521) was a Spanish explorer and ''conquistador'' known for leading the first official European expedition to Puerto Rico in 1508 and Florida in 1513. He was born in Santervás de Campos, Valladolid, Spain, in ...

led an expedition around the

Caribbean islands Most of the Caribbean countries are islands in the Caribbean Sea, with only a few in inland lakes. The largest islands include Cuba, Hispaniola, Jamaica and Puerto Rico. Some of the smaller islands are referred to as a ''rock'' or ''reef.'' ''I ...

and into

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

to find the

Fountain of Youth The Fountain of Youth is a mythical Spring (hydrology), spring which supposedly restores the youth of anyone who drinks or bathes in its waters. Tales of such a fountain have been recounted around the world for thousands of years, appearing in t ...

. Led by the rumors, 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 Philosophy ('love of wisdom' in Ancient Greek) is a systematic study of general and fundamental questions concerning topics like existence, reason, knowledge, Value (ethics and social sciences), value, mind, and language. It is a rational an ...

, sages and self-proclaimed wizards always made enormous efforts to find the secret of youth, both for themselves and their noble

patron Patronage is the support, encouragement, privilege, or financial aid that an organization or individual bestows on another. In the history of art, art patronage refers to the support that princes, popes, and other wealthy and influential people ...

s and sponsors. It was widely believed that some

potion A potion is a liquid "that contains medicine, poison, or something that is supposed to have magic powers." It derives from the Latin word ''potio'' which refers to a drink or the act of drinking. The term philtre is also used, often specifica ...

s may restore the youth. Another commonly cited approach was attempting to transfer the

essence Essence () has various meanings and uses for different thinkers and in different contexts. It is used in philosophy and theology as a designation for the property (philosophy), property or set of properties or attributes that make an entity the ...

of youth from young people to old. Some examples of this approach were sleeping with

virgin Virginity is a social construct that denotes the state of a person who has never engaged in sexual intercourse. As it is not an objective term with an operational definition, social definitions of what constitutes virginity, or the lack thereof ...

s or

child A child () is a human being between the stages of childbirth, birth and puberty, or between the Development of the human body, developmental period of infancy and puberty. The term may also refer to an unborn human being. In English-speaking ...

ren (sometimes literally sleeping, not necessarily having sex), bathing in or drinking their blood. The quest for rejuvenation reached its height with

alchemy Alchemy (from the Arabic word , ) is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practised in China, India, the Muslim world, and Europe. In its Western form, alchemy is first ...

. All around Europe, and also beyond, alchemists were looking for the

Philosopher's Stone The philosopher's stone is a mythic alchemical substance capable of turning base metals such as mercury into gold or silver; it was also known as "the tincture" and "the powder". Alchemists additionally believed that it could be used to mak ...

, 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 The scientific method is an Empirical evidence, empirical method for acquiring knowledge that has been referred to while doing science since at least the 17th century. Historically, it was developed through the centuries from the ancient and ...

and so to the medical advances of today. Serge Abrahamovitch Voronoff was a French surgeon born in Russia who gained fame for his technique of grafting monkey testicle tissue on to the testicles of men while working in France in the 1920s and 1930s. This was one of the first medically accepted rejuvenation therapies (before he was proved to be wrong around 1930–1940). The technique brought him a great deal of money, although he was already independently wealthy. As his work fell out of favor, he went from being a highly respected surgeon to a subject of ridicule. By the early 1930s, over 500 men had been treated in France by his rejuvenation technique, and thousands more around the world, such as in a special clinic set up in

Algiers Algiers is the capital city of Algeria as well as the capital of the Algiers Province; it extends over many Communes of Algeria, communes without having its own separate governing body. With 2,988,145 residents in 2008Census 14 April 2008: Offi ...

. Noteworthy people who had the surgery included Harold McCormick, chairman of the board of

International Harvester Company The International Harvester Company (often abbreviated IH or International) was an American manufacturer of agricultural and construction equipment, automobiles, commercial trucks, lawn and garden products, household equipment, and more. It wa ...

, and the aging premier of

Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...

. Rejuvenation technology and its effects on individuals and society have long been a subject of science fiction. The Misspent Youth and Commonwealth Saga by Peter F. Hamilton are among 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. The less perfect rejuvenation featured in the

Mars trilogy The ''Mars'' trilogy is a series of science fiction novels by Kim Stanley Robinson that chronicles the settlement and terraforming of the planet Mars through the personal and detailed viewpoints of a wide variety of characters spanning 187 year ...

Kim Stanley Robinson Kim Stanley Robinson (born March 23, 1952) is an American science fiction writer best known for his ''Mars'' trilogy. Many of his novels and stories have ecological, cultural, and political themes and feature scientists as heroes. Robinson has ...

results in long-term memory loss and sheer boredom that comes with extreme age. The post-mortal characters in the

Revelation Space ''Revelation Space'' is a 2000 science fiction novel by Welsh author Alastair Reynolds. It was the first novel (but not first published work of fiction) set in Reynolds's Revelation Space universe, eponymous universe. The novel reflects Reynolds ...

series have long-term or essentially infinite lifespans, and sheer boredom induces them to undertake activities of extreme risk.

Modern developments

Aging Ageing (or aging in American English) is the process of becoming Old age, older until death. The term refers mainly to humans, many other animals, and fungi; whereas for example, bacteria, perennial plants and some simple animals are potentiall ...

is the accumulation of

macromolecule A macromolecule is a "molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass." Polymers are physi ...

s, cells, tissues and

organs In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to a ...

in and on the body which, when it can no longer be tolerated by an

organism An organism is any life, living thing that functions as an individual. Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Many criteria, few of them widely accepted, have be ...

, ultimately leads to its

death Death is the end of life; the irreversible cessation of all biological functions that sustain a living organism. Death eventually and inevitably occurs in all organisms. The remains of a former organism normally begin to decompose sh ...

. 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 Maximum life span (or, for humans, maximum reported age at death) is a measure of the maximum amount of time one or more members of a population have been observed to survive between birth and death. The term can also denote an estimate of the maxi ...

laboratory A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratories are found in a variety of settings such as schools ...

animals, thereby achieving

. A few experimental methods such as replacing

hormone A hormone (from the Ancient Greek, Greek participle , "setting in motion") is a class of cell signaling, signaling molecules in multicellular organisms that are sent to distant organs or tissues by complex biological processes to regulate physio ...

s to youthful levels have had considerable success in partially rejuvenating laboratory animals and humans. A 2011 experiment involved breeding genetically manipulated mice that lacked an enzyme called telomerase, causing the mice to age prematurely and suffer ailments. When the mice were given injections to reactivate the enzyme, it repaired the damaged tissues and reversed the signs of aging. There are at least eight important hormones that decline with age: 1.

human growth hormone Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in ...

(HGH); 2. the sexual hormones: testosterone or oestrogen/progesterone; 3.

erythropoietin Erythropoietin (; EPO), also known as erythropoetin, haematopoietin, or haemopoietin, is a glycoprotein cytokine secreted mainly by the kidneys in response to cellular hypoxia; it stimulates red blood cell production ( erythropoiesis) in th ...

(EPO); 4. insulin; 5.

DHEA Dehydroepiandrosterone (DHEA), also known as androstenolone, is an endogenous steroid hormone precursor. It is one of the most abundant circulating steroids in humans. DHEA is produced in the adrenal glands, the gonads, and the brain. It functio ...

; 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. In line with this, recent experiments show that heterochronic parabiosis, i.e. connecting the circulatory systems of young and old animal, leads to the rejuvenation of the old animal, including restoration of proper stem cell function. Similar experiments show that grafting old muscles into young hosts leads to their complete restoration, whereas grafting young muscles into old hosts does not. These experiments show that aging is mediated by systemic environment, rather than being an intrinsic cell property. Clinical trials based on transfusion of young blood were scheduled to begin in 2014. Another intervention that is gaining popularity is epigenetic reprogramming. Through the use of

Yamanaka factors is a Japanese stem cell researcher and a Nobel Prize laureate. He is a professor and the director emeritus of Center for iPS Cell ( induced Pluripotent Stem Cell) Research and Application, Kyoto University; as a senior investigator at the ...

, aged cells can revert to a younger state. It has been demonstrated that reprogramming induces a youthful epigenetic state and can restore vision after injury. Only through reprogramming were stochastic epigenetic variations, which accumulate with age, successfully reversed, as demonstrated by a stochastic data-based clock. Most attempts at genetic repair have traditionally involved the use of a

retrovirus A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. After invading a host cell's cytoplasm, the virus uses its own reverse transcriptase e ...

to insert a new

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

into a random position on a

chromosome A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...

. But by attaching

zinc finger A zinc finger is a small protein structural motif that is characterized by the coordination of one or more zinc ions (Zn2+) which stabilizes the fold. The term ''zinc finger'' was originally coined to describe the finger-like appearance of a ...

s (which determine where

transcription factor In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription (genetics), transcription of genetics, genetic information from DNA to messenger RNA, by binding t ...

s bind) to

endonuclease In molecular biology, endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain (namely DNA or RNA). Some, such as deoxyribonuclease I, cut DNA relatively nonspecifically (with regard to sequence), while man ...

s (which break

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

strands),

homologous recombination Homologous recombination is a type of genetic recombination in which genetic information is exchanged between two similar or identical molecules of double-stranded or single-stranded nucleic acids (usually DNA as in Cell (biology), cellular organi ...

can be induced to correct and replace defective (or undesired) DNA sequences. The first applications of this technology are to isolate

stem cell In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can change into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type of cell ...

s from the

bone marrow Bone marrow is a semi-solid biological tissue, tissue found within the Spongy bone, spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It i ...

of patients having

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

disease

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, ...

s, to correct those mutations in laboratory dishes using zinc finger endonucleases and to transplant the stem cells back into the patients. More recent efforts leverage CRISPR-Cas systems or adeno-associated viruses (AAVs). Enhanced

DNA repair DNA repair is a collection of processes by which a cell (biology), cell identifies and corrects damage to the DNA molecules that encode its genome. A weakened capacity for DNA repair is a risk factor for the development of cancer. DNA is cons ...

has been proposed as a potential rejuvenation strategy. Stem cell

regenerative medicine Regenerative medicine deals with the "process of replacing, engineering or regenerating human or animal cells, tissues or organs to restore or establish normal function". This field holds the promise of engineering damaged tissues and organs by st ...

uses three different strategies: # Implantation of

s from

culture Culture ( ) is a concept that encompasses the social behavior, institutions, and Social norm, norms found in human societies, as well as the knowledge, beliefs, arts, laws, Social norm, customs, capabilities, Attitude (psychology), attitudes ...

into an existing tissue structure # Implantation of stem cells into a

tissue scaffold Tissue engineering is a biomedical engineering discipline that uses a combination of cells, engineering, materials methods, and suitable biochemical and physicochemical factors to restore, maintain, improve, or replace different types of biolog ...

that guides restoration # Induction of residual cells of a tissue structure to regenerate the necessary body part A

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

can not only regenerate a

limb Limb may refer to: Science and technology *Limb (anatomy), an appendage of a human or animal *Limb, a large or main branch of a tree *Limb, in astronomy, the curved edge of the apparent disk of a celestial body, e.g. lunar limb *Limb, in botany, t ...

, but can regenerate the

lens A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements'') ...

retina The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...

of an

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

and can regenerate an

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

. For regeneration the salamander tissues form a blastema by de-differentiation of mesenchymal cells, and the blastema functions as a self-organizing system to regenerate the limb. 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 Happiness is a complex and multifaceted emotion that encompasses a range of positive feelings, from contentment to intense joy. It is often associated with positive life experiences, such as achieving goals, spending time with loved ones, ...

. 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 The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

breast The breasts are two prominences located on the upper ventral region of the torso among humans and other primates. Both sexes develop breasts from the same embryology, embryological tissues. The relative size and development of the breasts is ...

face The face is the front of the head that features the eyes, nose and mouth, and through which animals express many of their emotions. The face is crucial for human identity, and damage such as scarring or developmental deformities may affect th ...

). There are also, as commonly found throughout history, many fake rejuvenation products that have been shown to be ineffective. Chief among these are powders, sprays, gels, and

homeopathic Homeopathy or homoeopathy is a pseudoscientific system of alternative medicine. It was conceived in 1796 by the German physician Samuel Hahnemann. Its practitioners, called homeopaths or homeopathic physicians, believe that a substance tha ...

substances that claim to contain growth hormones. Authentic growth hormones are only effective when injected, mainly due to the fact that the 191-amino acid protein is too large to be absorbed through the

mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...

s, and would be broken up in the stomach if swallowed. The Mprize scientific competition is under way to deliver on the mission of extending healthy human life. It directly accelerates the development of revolutionary new life extension therapies by awarding two cash prizes: one to the research team that breaks the world record for the oldest-ever mouse; and one to the team that develops the most successful late-onset rejuvenation. Current Mprize winner for rejuvenation is Steven Spindler. Caloric restriction (CR), the consumption of fewer calories while avoiding malnutrition, was applied as a robust method of decelerating aging and the development of age-related diseases. In 2020, scientists reported the reversion of ageing in human cells through nuclear reprogramming to

pluripotency Cell potency is a cell's ability to differentiate into other cell types. The more cell types a cell can differentiate into, the greater its potency. Potency is also described as the gene activation potential within a cell, which like a continuum ...

. Such process included resetting of

epigenetic clock An epigenetic clock is a Biomarkers of aging, biochemical test that can be used to measure age. The test is based on modifications that change over time and regulate how genes are expressed. Typically, the test examines DNA methylation levels, meas ...

, reduction of the inflammatory profile in

chondrocytes Chondrocytes (, ) are the only cells found in healthy cartilage. They produce and maintain the cartilaginous matrix, which consists mainly of collagen and proteoglycans. Although the word '' chondroblast'' is commonly used to describe an immatu ...

and restoration of youthful regenerative response to aged, human muscle stem cells, without abolishing cellular identity.

Strategies for engineered negligible senescence

The biomedical

gerontologist Gerontology ( ) is the study of the social, cultural, psychological, cognitive, and biological aspects of aging. The word was coined by Ilya Ilyich Mechnikov in 1903, from the Greek ('), meaning "old man", and ('), meaning "study of". The fi ...

Aubrey de Grey Aubrey David Nicholas Jasper de Grey (; born 20 April 1963) is an English biomedical gerontologist. He is the author of ''The Mitochondrial Free Radical Theory of Aging'' (1999) and co-author of '' Ending Aging'' (2007). De Grey is known for ...

has initiated a project, strategies for engineered negligible senescence (SENS), to study how to reverse the damage caused by aging. He has proposed seven strategies for what he calls the seven deadly sins of aging: # Cell loss can be repaired (reversed) just by suitable

exercise Exercise or workout is physical activity that enhances or maintains fitness and overall health. It is performed for various reasons, including weight loss or maintenance, to aid growth and improve strength, develop muscles and the cardio ...

in the case of

muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

. For other tissues it needs various

growth factor A growth factor is a naturally occurring substance capable of stimulating cell proliferation, wound healing, and occasionally cellular differentiation. Usually it is a secreted protein or a steroid hormone. Growth factors are important for ...

s to stimulate

cell division Cell division is the process by which a parent cell (biology), cell divides into two daughter cells. Cell division usually occurs as part of a larger cell cycle in which the cell grows and replicates its chromosome(s) before dividing. In eukar ...

, or in some cases it needs

stem cells In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can change into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type of cell ...

. # Senescent cells can be removed by activating the

immune system The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to bacteria, as well as Tumor immunology, cancer cells, Parasitic worm, parasitic ...

against them. Or they can be destroyed by

gene therapy Gene therapy is Health technology, medical technology that aims to produce a therapeutic effect through the manipulation of gene expression or through altering the biological properties of living cells. The first attempt at modifying human DNA ...

to introduce "suicide

s" that only kill senescent cells. #

Protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

cross-link In chemistry and biology, a cross-link is a bond or a short sequence of bonds that links one polymer chain to another. These links may take the form of covalent bonds or ionic bonds and the polymers can be either synthetic polymers or natural ...

ing can largely be reversed by

drugs A drug is any chemical substance other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Consumption of drugs can be via inhalation, injection, smoking, ingestio ...

that break the links. But to break some of the cross-links we may need to develop enzymatic methods. #

Extracellular This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...

garbage (like

amyloid Amyloids are aggregates of proteins characterised by a fibrillar morphology of typically 7–13 nm in diameter, a β-sheet secondary structure (known as cross-β) and ability to be stained by particular dyes, such as Congo red. In the human ...

) can be eliminated by

vaccination Vaccination is the administration of a vaccine to help the immune system develop immunity from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating ...

that gets

immune In biology, immunity is the state of being insusceptible or resistant to a noxious agent or process, especially a pathogen or infectious disease. Immunity may occur naturally or be produced by prior exposure or immunization. Innate and adaptive ...

cells to "eat" the garbage. # For intracellular junk we need to introduce new

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

s, possibly enzymes from soil

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

, that can degrade the junk (

lipofuscin Lipofuscin is the name given to fine yellow-brown pigment Granule (cell biology), granules composed of lipid-containing residues of Lysosome, lysosomal digestion. It is considered to be one of the aging or "wear-and-tear" pigments, found in the l ...

) that our own natural enzymes cannot degrade. # For

mitochondrial A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used ...

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 The cell nucleus (; : nuclei) is a membrane-bound organelle found in eukaryote, eukaryotic cell (biology), cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have #Anucleated_cells, ...

by gene therapy. The

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

experiences a high degree of

mutagenic In genetics, a mutagen is a physical or chemical agent that permanently changes genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level. As many mutations can cause cancer in ...

damage because most

free radicals In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired electron, unpaired valence electron. With some exceptions, these unpaired electrons make radicals highly chemical reaction, chemi ...

are generated in the

mitochondria A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is us ...

. A copy of the mitochondrial DNA located in the nucleus will be better protected from free radicals, and there will be better

when damage occurs. All mitochondrial

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

s would then be imported into the mitochondria. # For

cancer Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...

(the most lethal consequence of mutations) the strategy is to use

to delete the

s for

telomerase Telomerase, also called terminal transferase, is a ribonucleoprotein that adds a species-dependent telomere repeat sequence to the 3' end of telomeres. A telomere is a region of repetitive sequences at each end of the chromosomes of most euka ...

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. In 2009, Aubrey de Grey co-founded the

SENS Foundation The SENS Research Foundation is a non-profit organization that does research programs and public relations work for the application of regenerative medicine to aging. It was founded in 2009, located in Mountain View, California, US. The organiza ...

to expedite progress in the above-listed areas.

Scientific journal

* ''

Rejuvenation Research ''Rejuvenation Research'' is a bimonthly peer-reviewed scientific journal published by Mary Ann Liebert that covers research on rejuvenation and biogerontology. The journal was established in 1998. The current acting editor-in-chief is Ben Zealle ...

'' Editor:

. Publisher: Mary Ann Liebert, Inc. ISSN 1549-1684 – Published Bimonthly.

References

External links