The human kidney has nicotine receptors that are activated by smoking and could be related to smoking-related kidney damage, researchers have discovered.

"Initially, it was believed that the nicotine component of cigarette smoke was only responsible for the addictive effects of smoking," said researcher Edgar A. Jaimes, M.D., of the University of Miami School of Medicine. "However, now we are finding out that nicotine can have significant biological effects in other tissues."

The nicotine receptors are located on human mesangial cells in the kidneys' filtering units, called glomeruli. When Jaimes and colleagues exposed the mesangial cells to nicotine, proliferation of the cells rose by 50-80 percent. Production of fibronectin, a protein related to kidney scarring, rose about 50 percent.

"Often, if there is disease, the mesangial cells get activated, which produces collagen and fibronectin. This results in kidney scarring and progressive kidney disease," Jaimes explained. "There is evidence that smokers with health conditions like diabetes or high blood pressure progress to kidney disease faster than nonsmokers."

The research was presented at the American Heart Association's 60th Annual Fall Conference of the Council for High Blood Pressure Research.