Effects of smoking on renal hemodynamics in healthy volunteers and in patients with glomerular disease

Patients with renal disease who smoke have a poor renal functional prognosis, but the mechanisms involved have not been explored. In this controlled study, the effects of smoking and sham smoking were compared in 15 healthy normotensive volunteers. All were occasional smokers and abstained from smoking for 48 h as documented by urinary cotinine measurements. These data were compared with those of seven patients with biopsy-confirmed IgA glomerulonephritis, also occasional smokers. Renal clearance examinations were obtained after hydration in the supine position before and while smoking two cigarettes or sham cigarettes in random order on 2 consecutive days. GFR and effective renal plasma flow were determined using In111-diethylenetriamine penta-acetic acid and 131I-hippurate with a dual tracer infusion clearance technique. In an ancillary study with six volunteers, the effect of smoking was compared with the effect of nicotine-containing chewing gum. In healthy volunteers, sham smoking caused a minor but significant increase of mean arterial pressure (MAP) and GFR with no significant change of effective renal plasma flow, filtration fraction (FF), or renovascular resistance. Smoking caused a significant and more marked increase of MAP (from baseline 92.8+/-8.98 to 105+/-7.78 mmHg) and heart rate (from 61.7+/-7.52 to 86.4+/-9.87 min(-1)), accompanied by a significant increase in arginine vasopressin (from 1.27+/-0.72 to 19.9+/-27.2 pg/ml) and epinephrine (from 37+/-13 to 140+/-129 pg/ml). During smoking, GFR decreased in all but one volunteer (from 120+/-17.7 to 102+/-19.3 ml/min per 1.73 m2), and this was accompanied by a significant decrease of FF (from 21.3+/-4.24 to 17.4+/-3.41%) and an increase in renovascular resistance (from 97.6+/-27.2 to 108+/-30.4 mmHg x min/ml per 1.73 m2). These findings were reproduced with nicotine-containing chewing gum. In contrast, when patients with IgA glomerulonephritis smoked, a similar increment in MAP was noted, the changes of FF were not uniform, and a small but consistent increase of urinary albumin/creatinine ratio was observed. An additional 20 volunteers were subjected to the smoking arm of the study for statistical evaluation of the GFR change in patients. The difference between the change of GFR between all volunteers (n = 35) and patients (n = 7) was significant (P < 0.005). It is concluded that the known effects of smoking and nicotine on the sympathetic nervous system and on systemic hemodynamics are accompanied by significant acute changes in renal hemodynamics and albuminuria. These findings are of interest because of the known effects of smoking on progression of renal disease.