Position statement on human aging

SENS and the Polarization of Aging-Related Research

The second Strategies for Engineered Negligible Senescence conference (SENS II) featured some very provocative ideas. The explicit objective of extending human life span indefinitely has opened a large rift between the meeting's organizer and those who believe he is acting unscientifically, perhaps recklessly. Two SENS conference participants present their views on the divisive nature of SENS.

Anti-aging medicine: A patient/practitioner movement to redefine aging

Having enjoyed tremendous growth for the past 5 years, the anti-aging medicine movement is redefining aging so that it becomes a target for biomedical intervention. Targeting aging for intervention dislodges popular understandings of aging: for anti-aging practitioners it no longer matters if aging is natural since it can be itself the target of therapy. So-called "age-associated" diseases like cancer are, in this framework, conceived of as symptoms of aging. Anti-aging medicine is a broad term that may comprise groups selling remedies over the Internet, companies touting the "anti-aging"ness of their products, practitioners who work outside of scientific medicine, and practitioners of anti-aging medicine in clinics who believe that their work is strictly scientific. This article, drawing from more than 3 years of ethnographic interviews, participant observation in clinics and conferences, and a review of the literature, considers the last group. It examines the involvement stories of anti-aging medicine practitioners in two Western United States metropolitan cities. These stories reflect the practices of anti-aging medicine practitioners and the accompanying rationale for involvement. Often originally patients themselves, practitioners frame their involvement with the anti-aging movement in three ways. First, they describe aging as it is currently experienced as a time of decline, suffering, and weakness. This anguish is not inevitable, they argue, and their work toward treating aging biomedically is situated as clearly moral. Secondly, intense frustration with the current biomedical environment has motivated practitioners to look for other ways in which to practice: anti-aging medicine is their chosen alternative. Finally, with dramatic expectations of future biotechnologies and disdain for current medical treatments of old age, anti-aging practitioners embrace a scientific revolutionary identity. These stories of migrations from patient to practitioner reveal the values upon which this movement is grounded and how coming to be a part of it is as much about the movement's mission as it is the origins of the migrations.

Understanding and modulating ageing

Ageing is characterized by a progressive accumulation of molecular damage in nucleic acids, proteins and lipids. The inefficiency and failure of maintenance, repair and turnover pathways is the main cause of age-related accumulation of damage. Research in molecular gerontology is aimed at understanding the genetic and epigenetic regulation of survival and maintenance mechanisms at the levels of transcription, post-transcriptional processing, post-translational modifications, and interactions among various gene products. Concurrently, several approaches are being tried and tested to modulate ageing in a wide variety of organisms. The ultimate aim of such studies is to improve the quality of human life in old age and prolong the health-span. Various gerontomodulatory approaches include gene therapy, hormonal supplementation, nutritional modulation and intervention by free radical scavengers and other molecules. A recent approach is that of applying hormesis in ageing research and therapy, which is based on the principle of stimulation of maintenance and repair pathways by repeated exposure to mild stress. A combination of molecular, physiological and psychological modulatory approaches can realize "healthy ageing" as an achievable goal in the not-so-distant future.

Antiaging Medicine and Mild Cognitive Impairment: Practice and Policy Issues for Geriatrics

The claim that aging itself is treatable or even preventable has repeatedly been made over the centuries. Antiaging medicine is the current leader of approaches that even claim that geriatrics as a discipline will become increasingly unnecessary. The concept of mild cognitive impairment (MCI) as a condition intermediate between normal cognitive aging and Alzheimer's disease highlights the conceptual and practical difficulty of differentiating aging from disease. What should geriatricians and their organizations make of scientifically mainstream attempts to decelerate, arrest, or compress aspects of the normal human aging, including the brain aging process? This article reviews the political, philosophical, practice-related, and economical implications of antiaging medicine for geriatrics using MCI as a practical example. It concludes by suggesting actions that geriatricians should consider to strengthen their profession and to improve patient care in response to the challenges of longevity medicine.

Thermodynamics and Information in Aging: Why Aging Is Not a Mystery and How We Will Be Able to Make Rational Interventions

Currently, the aging research field lacks consensus in its focus and methodology. Foundational principles, such as the evolutionary origins and physiological definition of aging, remain controversial. The aim of this paper is to resolve these issues. By applying the concepts of thermodynamics and information in an evolutionary context, the aging phenotype can be derived from first principles. Life uses information storage to maintain its distance from thermodynamic equilibrium. Since it is impossible to make any process 100% efficient, a selective force (i.e., natural selection) is needed to maintain the information's viability. Natural selection operates upon generations, and for reasons discussed subsequently, the somatic body cannot implement an analogous selective process. The aging phenotype we see can be derived from this model along with a number of insights that will enhance our ability to make intelligent and rational interventions.

Ethical and legal issues in antiaging medicine

The development of specific antiaging treatments and the emergence of the practice of antiaging medicine have created new ethical and legal issues. The ultimate desirability of treatments designed to alter human aging is currently an actively debated issue that needs to emerge as an issue of public dialogue, given the potentially dramatic effect these therapies could have on both individual health and societal structure. Current therapies carry many doubts about their safety and effectiveness, which makes the practice of antiaging medicine with the prescription of these therapies a challenging issue from both a legal and ethical perspective. Finally, although the practice of antiaging medicine is not directly recognized and regulated by legislation, both anti-aging treatments and practice are regulated by emerging state and federal legislation that is evolving to address the emerging area of complementary and alternative medicine.

Drug therapy in the elderly

Drug dosage in the elderly requires an understanding of the age-dependent changes in drug disposition and sensitivity. The most important pharmacokinetic alteration is a decline in renal function, the elderly should therefore be treated as renally insufficient patients. Metabolic clearance is primarily reduced with drugs that display high hepatic extraction, whereas the metabolism of drugs with low hepatic extraction usually is not diminished. The reduction of metabolic clearance is especially pronounced in malnourished or frail patients. The water content of the aging body decreases, the fat content rises. Hence the distribution volume of hydrophilic drugs may be reduced in the elderly, resulting in increased plasma concentrations. In contrast, the distribution volume of liphophilic drugs is increased, their plasma concentrations may decrease. Intestinal absorption of most drugs is not altered in the elderly. Aside of these pharmacokinetic changes, one of the characteristics of old age is a progressive decline in counterregulatory (homeostatic) mechanisms. Therefore, drug effects are attenuated less, the responses are usually stronger than in younger subjects, the rate and intensity of adverse effects are higher. Examples of drug actions augmented is this manner are postural hypotension with agents that lower blood pressure, dehydration and electrolyte disturbances in response to diuretics, bleeding complications with oral anticoagulants, hypoglycemia with antidiabetics, and gastrointestinal irritation with non-steroidal anti-inflammatory drugs. The brain is an especially sensitive drug target in old age. Psychotropic drugs, anticonvulsants, and centrally acting antihypertensives may impede intellectual function and motor coordination. Hence drugs should be used restrictively in geriatric patients.

Anti-aging medicine--the good, the bad, and the ugly

Complementary and alternative medicine has flourished since the beginning of time because of a human need to postpone the aging process and to reverse disease. Complementary and alternative medicine sells, because in some cases it works as well or better than mainstream medicine. In addition, many practitioners of complementary medicine understand Hippocrates' aphorism: "It is more important to know the person that has the disease than the disease the person has." It is important to recognize that spending time with the patient is often as therapeutic as drugs. CAM offers patients the time, touch, attention, and level of personal interaction that are increasingly uncommon in contemporary medical care. There is a major need for large and appropriately designed studies to test the effectiveness of complementary techniques. As in other areas of health care, studies in the elderly are consistently lacking. With the growing interest in CAM, it is important for medical providers to keep an open mind--to both the potential benefits and potential harms of alternative treatments. When treatments are shown to be dangerous or ineffective, we must educate the public and work to remove these therapies from the market place. When treatments are proven effective, Western and Eastern medical providers must work together with patients to provide the most appropriate and comprehensive health care.

Antiaging methods and medicines for the memory

The interaction of bedside and basic science has led to the identification ofa short list of pathological proteins as causal in Alzheimer's disease. AI3P has received the most attention, and work with animal models has reinforced the evidence that overproduction of ABP causes cognitive impairments. Animal models are now being used to discover and develop unique therapeutics directed at reversing the deleterious effects of ABP. These models strongly suggest that established Alzheimer's disease might be reversible, not just preventable. Animal models are also demonstrating that other peptides and proteins can enhance or impair cognitive function. These peptides and proteins add further to the list of possible therapeutic candidates. Approaches such as these, and not the commercial antiaging remedies that have no scientific basis, will eventually provide medicine for memory enhancement.

Hormonal fountains of youth

Any hope of a fountain of youth to stop people from getting older is a long way off, with science just beginning to understand the complex genetic, physical, and hormonal causes of aging. Clearly, modem research has demonstrated that the concept of a hormonal fountain of youth is predominantly mythology. The best evidence supporting use of hormonal replacement is vitamin D and estrogen replacement to prevent hip fractures. Other than that, treatment should be limited to hormone replacement in persons who have endocrine disease.

When drug therapy gets old: pharmacokinetics and pharmacodynamics in the elderly

The age-related changes in the functions and composition of the human body require adjustments of drug selection and dosage for old individuals. Drug excretion via the kidneys declines with age, the elderly should therefore be treated as renally insufficient patients. The metabolic clearance is primarily reduced with drugs that display high hepatic extraction ('blood flow-limited metabolism'), whereas the metabolism of drugs with low hepatic extraction ('capacity-limited metabolism') usually is not diminished. Reduction of metabolic drug elimination is more pronounced in malnourished or frail subjects. The water content of the aging body decreases, the fat content rises, hence the distribution volume of hydrophilic compounds is reduced in the elderly, whereas that of lipophilic drugs is increased. Intestinal absorption of most drugs is not altered in the elderly. Aside of these pharmacokinetic changes, one of the characteristics of old age is a progressive decline in counterregulatory (homeostatic) mechanisms. Therefore drug effects are mitigated less, the reactions are usually stronger than in younger subjects, the rate and intensity of adverse effects are higher. Examples of drug effects augmented is this manner are postural hypotension with agents that lower blood pressure, dehydration, hypovolemia, and electrolyte disturbances in response to diuretics, bleeding complications with oral anticoagulants, hypoglycemia with antidiabetics, and gastrointestinal irritation with non-steroidal anti-inflammatory drugs. The brain is an especially sensitive drug target in old age. Psychotropic drugs but also anticonvulsants and centrally acting antihypertensives may impede intellectual functions and motor coordination. The antimuscarinic effects of some antidepressants and neuroleptic drugs may be responsible for agitation, confusion, and delirium in elderly. Hence drugs should be used very restrictively in geriatric patients. If drug therapy is absolutely necessary, the dosage should be titrated to a clearly defined clinical or biochemical therapeutic goal starting from a low initial dose.

Vitamin B1 blocks damage caused by hyperglycemia

Diabetes accelerates the aging process and leads to complications that include blindness, renal failure, nerve damage, stroke, and cardiovascular disease. It has been hypothesized that high plasma glucose concentrations are responsible for increased mitochondrial free radical production and subsequent inactivation of glyceraldehyde phosphate dehydrogenase (GAPDH) in vascular endothelial cells and other cells implicated in these complications. As a result of the decreased ability of GAPDH to process upstream metabolites, three pathways of metabolic damage are activated, which include the advanced glycation end-product formation pathway, the protein kinase C pathway, and the hexosamine pathway. All three pathways have been implicated in abnormal cell signaling in diabetes. A group of German and U.S. scientists has now found that treating diabetic rats with high doses of benfotiamine, a lipid-soluble form of vitamin B1, can prevent diabetic retinopathy and all three forms of metabolic damage by stimulating transketolase activity and thus diverting excess metabolites toward the pentose pathway. Although vitamin B1 is available over the counter, the researchers at this time do not advocate self-treatment without further clinical data.

The war on "anti-aging medicine"

Leading members of the gerontological community have recently launched a war on anti-aging medicine, seeking to discredit what they judge to be fraudulent and harmful products and therapies, and to distinguish their research from what they regard as the pseudoscience of the anti-aging movement. This article interprets the contemporary war on anti-aging medicine as largely an attempt by established gerontological researchers to preserve their hard-won scientific and political legitimacy, as well as to maintain and enhance funding for research on the basic biological mechanisms of aging. First, it recounts the difficult struggle of U.S. biogerontologists to join the scientific mainstream in terms of legitimization and public funding. Second, it examines how elements of a contemporary anti-aging movement seem to threaten the hard-won public legitimacy of established gerontological researchers and practitioners. Third, it looks at the "boundary work" responses of the gerontological community to the anti-aging movement. Finally, it assesses the consequences of the war on anti-aging medicine to date.