EFFECTS OF SMOKING ON RENAL HEMODYNAMICS IN HEALTHY-VOLUNTEERS AND INPATIENTS WITH GLOMERULAR-DISEASE

Patients with renal disease who smoke have a poor renal functional pro gnosis, but the mechanisms involved have not been explored. In this co ntrolled 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 mea surements. These data were compared with those of seven patients with biopsy-confirmed IgA glomerulonephritis, also occasional smokers. Rena l clearance examinations were obtained after hydration in the supine p osition before and while smoking two cigarettes or sham cigarettes in random order on 2 consecutive days. GFR and effective renal plasma flo w were determined using In-111-diethylenetriamine pentaacetic acid and I-131-hippurate with a dual tracer infusion clearance technique. In a n ancillary study with six volunteers, the effect of smoking was compa red with the effect of nicotine-containing chewing gum. In healthy vol unteers, sham smoking caused a minor but significant increase of mean arterial pressure (MAP) and GFR with no significant change of effectiv e renal plasma flow, filtration fraction (FF), or renovascular resista nce. Smoking caused a significant and more marked increase of MAP (fro m 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 in crease 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 smo king, GFR decreased in all but one volunteer (from 120 +/- 17.7 to 102 +/- 19.3 ml/min per 1.73 m(2)), and this was accompanied by a signifi cant decrease of FF (from 21.3 +/- 4.24 to 17.4 +/- 3.41%) and an incr ease in renovascular resistance (from 97.6 +/- 27.2 to 108 +/- 30.4 mm Hg . min/ml per 1.73 m(2)), These findings were reproduced with nicoti ne-containing chewing gum. In contrast, when patients with IgA glomeru lonephritis 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 we re subjected to the smoking arm of the study for statistical evaluatio n of the GFR change in patients. The difference between the change of GFR between all volunteers (n = 35) and patients (n = 7) was significa nt (P < 0.005). It is concluded that the known effects of smoking and nicotine on the sympathetic nervous system and on systemic hemodynamic s are accompanied by significant acute changes in renal hemodynamics a nd albuminuria. These findings are of interest because of the known ef fects of smoking on progression of renal disease.