According to Greek mythology, the sun god Apollo offered to give the priestess Sybil of Cumae anything she desired in return for having sex with him. Sybil foolishly asked for centuries of life without including a demand that she remain forever young and beautiful. Consequently, she aged as centuries passed, and she abandoned all interest in living. Although we Americans have found ways to extend our lifetimes by years, though not by centuries, we still face the dilemma the mythical Sybil experienced: We may live decades longer than our ancestors, but we still age. We want mind and body agility and ability along with longevity, but realizing that dream still remains beyond our reach.
As we mature, we generally experience growth spurts and pass developmental milestones. For most individuals, physical abilities and performance peak at about 18 to 20 years of age. When our cognitive [thinking] abilities peak is less well-established, but most indicators suggest it is in our twenties. As we age, we lose cognitive abilities, such as memory function and mathematical skills, and develop increasingly limited resilience in organs other than our brains.
Both men and women in the general population exhibit what might be called ‘decay’ spurts at about 44 and 60 years of age. Presumably, evolution determined that we were expendable just after surviving long enough to raise, protect, and educate another generation of our species. Consequently, there is a general decline in organ function and reliability in many, if not most of us, as we enter the fifth decade of life. Forty-four years might strike most of us as excessively brief, but it is relatively generous when compared to the seven days of adult life Nature accords the Saturnid moth. (Yes, I was an entomologist.)
The later assault on our viability when we reach 60 years of age is apparently encoded in our genes and may have evolved simply to relieve our species of the burdens imposed on the general population by increasingly dependent individuals. Nature appears intent on frustrating our efforts to survive. Despite this predetermined ‘expiration date,’ advances in public health measures, including waste management, water purification, and food safety, as well as advances in general medicine, including vaccine development, antibiotics, and hormone supplements, have helped push the life expectancy of the average American well past 70 years of age. What we are still failing at is the preservation of body and mind as we age.
One of the most common and most identifiable challenges to our intellectual function is Alzheimer’s disease. This is a degenerative disease of the brain. There does not appear to be an infectious agent or vitamin deficiency responsible for the brain rot resulting from this disease, but there are highly consistent changes in the brain that establish the diagnosis. Aside from the loss of nerve cells, there is an abnormal accumulation of a material, called amyloid, that develops in and about areas of nerve cell loss, as well as protein tangles, called tau or neurofibrillary tangles, that develop inside brain nerve cells.
More than fifty years ago, many physicians and scientists believed that Alzheimer’s disease developed as brain cells depleted chemical transmitters that allowed nerve cells to communicate with each other. Drugs, including donepezil (Aricept) and memantine [Namenda], were developed for the management of Alzheimer’s disease on the assumption that they would help correct this disturbance in chemical transmitters. These drugs delayed cognitive decline slightly, but only transiently, in people with Alzheimer’s disease but provided no longterm benefits.
More recently, pharmaceutical agents have been developed that target the amyloid accumulating in the brain and in blood vessels supplying the brain in people with Alzheimer’s disease. These agents remove amyloid from the brain and affected blood vessels and slow the progression of cognitive loss in people with Alzheimer’s disease. Drugs recently approved in the U.S. that accomplish this include aducanumab (Aduhelm), lecanemab (Leqembi) and donanemab (Kisunla). Unlike other amyloid-depleting drugs developed, lecanemab can be given subcutaneously, an option that makes it feasible for patients to self administer.
All of the amyloid-targeting drugs yet developed have the disadvantage of triggering inflammation in the brains of some of the patients treated. Additionally, at best they slow the progression of Alzheimer’s disease but do not reverse or even stop the cognitive decline of people with the disease. This, along with the high cost of the drugs, has led agencies in Europe to refuse to designate these drugs as “safe and effective.”
Mother Nature may be frustrated in her efforts to limit our lifespans to less than a century, but she will not yet allow us to escape Sybil’s fate of survival “without benefits,” those benefits including the wherewithal to live and function independently. Diet, exercise, and drugs may improve our quality of life after 44 years of age, but they will not spare us the fate written into our genes.
Dr. Lechtenberg is an Easton resident who graduated from Tufts University and Tufts Medical School in Massachusetts and subsequently trained at The Mount Sinai Hospital and Columbia-Presbyterian Medical Center in Manhattan. He worked as a neurologist at several New York Hospitals, including Kings County and The Long Island College Hospital, while maintaining a private practice, teaching at SUNY Downstate Medical School, and publishing 15 books on a variety of medical topics. He worked in drug development in the U.S., as well as in England, Germany, and France.
