Renal Nicotine Receptors Are Identified
Nicotine receptors on kidney cells may explain why cigarette smokers are vulnerable to kidney damage, researchers say.
"There is evidence that smokers with health conditions like diabetes or high blood pressure progress to kidney disease faster than non-smokers," said investigator Edgar Jaimes, MD, associate professor of medicine. "It's not clear which of the many components in cigarette smoke causes this, so we decided to try to clarify the role that nicotine may have."
Dr. Jaimes and his colleagues at the University of Miami identified nicotine receptors on human mesangial cells in glomeruli. Activation of these cells in response to disease can produce collagen and fibronectin, resulting in kidney scarring and progressive kidney disease.
The researchers added nicotine to mesangial cells at a concentration similar to what could be expected in the blood of smokers. Exposure to nicotine increased mesangial cell proliferation by 50%-80%. Researchers measured the level of scarring or fibrosis related to nicotine exposure by examining the production of fibronectin. They found nicotine increased production of fibronectin by 50%.
When researchers exposed the cells to a compound that blocked nicotine receptors, the effects of nicotine were reduced. "This may be a possible mechanism for how smoking increases the risk of kidney disease," Dr. Jaimes said.