Strategies for engineered negligible senescence (SENS) is a range of proposed regenerative medical therapies, either planned or currently in development, for the periodic repair of all age-related damage to human tissue. These therapies have the ultimate aim of maintaining a state of negligible senescence in patients and postponing age-associated disease. SENS was first defined by British biogerontologist Aubrey de Grey. Many mainstream scientists believe that it is a fringe theory.
While some biogerontologists support the SENS program, others contend that the ultimate goals of de Grey's programme are too speculative given the current state of technology. The 31-member Research Advisory Board of de Grey's SENS Research Foundation have signed an endorsement of the plausibility of the SENS approach.
Framework
The term "negligible senescence" was first used in the early 1990s by professor Caleb Finch to describe organisms such as lobsters and hydras, which do not show symptoms of aging. The term "engineered negligible senescence" first appeared in print in Aubrey de Grey's 1999 book The Mitochondrial Free Radical Theory of Aging. De Grey defined SENS as a "goal-directed rather than curiosity-driven" approach to the science of aging, and "an effort to expand regenerative medicine into the territory of aging".
The ultimate objective of SENS is the eventual elimination of age-related diseases and infirmity by repeatedly reducing the state of senescence in the organism. The SENS project consists in implementing a series of periodic medical interventions designed to repair, prevent or render irrelevant all the types of molecular and cellular damage that cause age-related pathology and degeneration, in order to avoid debilitation and death from age-related causes.
Strategies
As described by SENS, the following table details major ailments and the program's proposed preventative strategies:
Scientific reception
While some fields mentioned as branches of SENS are supported by the medical research community, e.g., stem cell research, anti-Alzheimers research and oncogenomics, the SENS programme as a whole has been a highly controversial proposal. Many of its critics argue that the SENS agenda is fanciful and that the complicated biomedical phenomena involved in aging contain too many unknowns for SENS to be fully implementable in the foreseeable future.
Cancer may deserve special attention as an aging-associated disease, but the SENS claim that nuclear DNA damage only matters for aging because of cancer has been challenged in other literature, as well as by material studying the DNA damage theory of aging. More recently, biogerontologist Marios Kyriazis has criticised the clinical applicability of SENS by claiming that such therapies, even if developed in the laboratory, would be practically unusable by the general public. De Grey responded to one such criticism.
2005 EMBO Reports statement
In November 2005, 28 biogerontologists published a statement of criticism in EMBO Reports, "Science fact and the SENS agenda: what can we reasonably expect from ageing research?," arguing "each one of the specific proposals that comprise the SENS agenda is, at our present stage of ignorance, exceptionally optimistic," and that some of the specific proposals "will take decades of hard work [to be medically integrated], if [they] ever prove to be useful." The researchers argue that while there is "a rationale for thinking that we might eventually learn how to postpone human illnesses to an important degree," increased basic research, rather than the goal-directed approach of SENS, is currently the scientifically appropriate goal.
Technology Review contest
In February 2005, the MIT Technology Review published an article by Sherwin Nuland, a Clinical Professor of Surgery at Yale University and the author of "How We Die", that drew a skeptical portrait of SENS, at the time de Grey was a computer associate in the Flybase Facility of the Department of Genetics at the University of Cambridge. While Nuland praised de Grey's intellect and rhetoric, he criticized the SENS framework both for oversimplifying "enormously complex biological problems" and for promising relatively near-at-hand solutions to those unsolved problems.