Oxidative stress is an imbalance between the production of reactive oxygen species (free radicals) and antioxidant defenses. [1] The body’s cells produce free radicals, which are nitrogen- or oxygen-containing molecules with an uneven number of electrons [2], during normal metabolic processes. [3] Meanwhile, cells also produce antioxidants that neutralize these free radicals to prevent excessive cell and tissue damage. In general, the body is able to maintain a balance between antioxidants and free radicals. [3] However, this balance could be disrupted under certain conditions or environmental stress or infection, and uncontrolled oxidative stress can accelerate the aging process.[3]

As human beings with trillions of cells, each of which has their associated millions of copies of myriad proteins and other biological molecules, it’s something of a miracle that enough of the molecules bump together at the right times to keep us alive and functional. In addition to our own cells, we also coexist with microscopic neighbors, including various beneficial bacteria, while fending off pathogens like disease-causing bacteria, viruses, protozoans, and fungi. We often consider the bacteria and viruses in most human diseases, which invoke our immune systems to fight them to keep us healthy, but it also makes sense that the fungi can affect us as well, a topic in cancer research that is gaining attention.

Once upon a time when I was a fledgling science nerd in high school, I started learning about the process of apoptosis, which remains to this day the most studied form of cell death in various functions including organismal development and defense against cancer. As an immunologist-in-training, I also learned about the classical complement pathway that the immune system uses to destroy infected cells, and also necrotic cell death or necroptosis (which is full of really gross pictures if you dare to Google it). Of course, I learned about autophagy in graduate school and really appreciate its utility in normal physiology and disease, while very recently I read about ferroptosis as yet another programmed cell death (PCD) pathway. Right around when the Nobel Prize was awarded to recognize the elucidation of PCD, pyroptosis came about as a novel PCD pathway that is continuing to gain steam in its clinical relevance. It seems logical for cells and organisms to have redundant systems in place to clear away damaged and malignant cells before a health crisis can emerge if the cell evades the primary route of apoptosis.