The mainstream of longevity research is the domain of metabolic exploration and manipulation: scientists in search of a better human metabolism that will age at a somewhat slower rate. This is a realm apart from the minority efforts to repair biological damage and thereby reverse aging. Here is an example of the sort of metabolic research presently taking place: "scientists report finding a molecular 'switch' that can 'turn off' some cellular processes that are protective against aging and metabolic diseases. While more research is needed, the findings may open doors for new drug treatments to halt or slow development of metabolic diseases like type 2 diabetes or heart disease. ... [Researchers] focused on the role of the protein SMRT (silencing mediator of retinoid and thyroid hormone receptors) in the aging process. They found aged cells accumulate more SMRT and wanted to see if SMRT increases the damaging effects of oxidative stress on mitochondria, the cell component that converts food and oxygen into energy and powers metabolic activities. Oxidative stress is a cellular process that damages DNA, protein, and other cell functions and can lead to age-related diseases such as type 2 diabetes, Alzheimer's, Parkinson's, and atherosclerosis. ... in older animals SMRT acts like a 'switch,' turning off the protective cellular activities of proteins known as peroxisome proliferator-activated receptors (PPARs). PPARs help regulate genes that promote fat burning to maintain lipid (blood fat) balance and reduce oxidative stress. The researchers were able to reduce the negative effects of oxidative stress by giving antioxidants or drugs known to turn the protective activities of PPARs back on."