A few months ago, I interviewed Jeffrey Cummings, a neurobiologist at the University of Nevada, Las Vegas who has worked on Alzheimer’s disease for decades. It seemed to me that the field was not making much progress, despite years of work and billions of dollars in funding. The bulk of drug discovery research for Alzheimer’s disease focused on amyloids, the misfolded protein clumps that dot patients’ brains. But even with a few FDA-approved drugs available, improvements in patients’ lives were hard to detect. Was focusing on amyloids a mistake?
Not at all, according to Cummings. The mistake wasn’t in investigating amyloids, but in assuming that amyloids were the only player creating the disease. “Amyloid seems like it establishes the ecology in which other processes can occur that result in cell dysfunction and dementia,” he said. A cavalcade of other important factors drive the development of Alzheimer’s disease, from tau tangles to neuroinflammation to immune dysfunction. Each is a node in a large network of Alzheimer’s disease contributors.
For me, that was an extremely clarifying way to frame things: the ecology of a disease.
That conversation happened in August 2022, but I’ve been thinking about it ever since, like a dog chewing on an old piece of rope. It’s simpler and more comforting as a journalist and a patient to think of diseases as only having single causes. Diseases are bodily invasions, from outside infections to internal processes gone awry. It’s a neat and tidy story when a disease can be cured with, say, a dose of antibiotics. But that is rarely the case.
It is important for scientists and journalists alike to stop thinking of most diseases as resulting from a single cause. The more we learn about any particular disease, the farther we move from silver bullet solutions. It is easy to see cancer as a classic disease that’s too complex to be treated in one way. Cancer rates and the ways those cancers behave vary by location, environmental exposure to toxins, genetics, and seemingly, bad luck (1). Treating cancer is just as much a matter of prevention — avoiding smoking, getting tested for common genetic markers like BRCA1/2 — as it is drugs. We should start viewing every disease this way.
Every so often, a group of scientists will report that they successfully designed a universal flu vaccine that will eliminate the need for seasonal vaccines (2). But as DDN reported in September, influenza doesn’t work that way. The virus mutates too quickly and affects people in too many different ways. Different people with different health conditions at different periods of their lives will all need different vaccines and different treatments.
Instead of hoping that new research findings will lead to a simple path to a cure, I am trying to think of biomedical research as uncovering a complex map of each disease. Different starting conditions — age, health, genetics, etc. — will lead to different outcomes in almost any disease. With that picture in mind, I hope to view what lays ahead for biology in a more unified and accurate way.
- Olsen, J. & Overvad, K. The Concept of Multifactorial Etiology of Cancer. Pharmacology & Toxicology 72, 33–38 (1993).
- Park, J. et al. An inactivated multivalent influenza A virus vaccine is broadly protective in mice and ferrets. Sci Transl Med 14, eabo2167 (2022).