For the first time, the scientists have found nicotine receptors on kidney cells, a further suggestion that smoking cigarettes can speed up kidney damage.
"There is a lot of clinical evidence with patients indicating that patients suffering from kidney disease and who smoke cigarettes have a worse prognosis than non-smoking patients," said co-author of the research Dr Edgar A. Jaimes, an associate professor of medicine at the University of Miami School of Medicine. "They end up on dialysis faster. We have discovered one of the possible mechanisms that makes that take place."
These findings were announced Wednesday at the American Heart Association’s Annual Fall Conference of the Council for High Blood Pressure Research, in San Antonio.
The kidneys control the body’s excretion and re-absorption of water and electrolytes - including calcium, magnesium, potassium, sodium and sulfate. If the kidneys are unable to excrete these substances, fluid and blood volume rises. High build-ups of waste products in the blood may make a patient feel sick, in accordance with background information for the research.
Jaimes explained that kidney disease is the most frequent cause of high blood pressure. Even subtle disruptions in kidney function can have a negative effect on blood pressure, due to the fact that the kidneys control levels of salt in body fluids. If kidney disease gets worse, it can result in kidney failure, requiring dialysis or a kidney transplant.
Nicotine receptors on kidney
Jaimes and his team at the Miami Veterans Administration Medical Centre searched for nicotine receptors on kidney cells and discovered them. "They’ve never been described before," he explained.
The receptors were discovered on mesangial cells, which are situated in the glomeruli - the kidneys filtering units. In kidney disease, those cells are frequently activated to produce collagen and fibronectin, molecules leading to kidney scarring.
That’s just what happened when the scientists added nicotine to cultures of kidney cells at a concentration similar to what could be expected in an average smoker. Mesangial cell proliferation rose by fifty per cent to eighty per cent. The production of fibronectin rose by nearly fifty per cent. Those effects were decreased when a compound blocking the nicotine receptors was added.
"This damage happens on top of everything else that smoking does," Jaimes said.
He stated that it is a finding with a practical application for healthcare specialists treating kidney disease.
"The major thing for patients who suffer from kidney disease is that smoking cessation should be part of the treatment," Jaimes said.
