Release of Renal Renin in Patients under Long-Term Dailysis Treatment

Abstract

Plasma renin activity (PRA) was studied in 61 patients under long-term dialysis treatment. They were divided into three groups, low (0.1-5.0 ng/ml), normal (5.1-30.0 ng/ml), and high renin groups (more than 30.1 ng/ml) according to the levels of PRA. The difference in clinical features in the three groups and the factors influencing the secretion of renin were investigated. 1) With regard to the pre-dialysis PRA (resting PRA), low renin levels were found in 13.1 per cent of patients, normal in 65.5 per cent, and high in 21.4 per cent. 2) The pre-dialysis PRA (resting PRA) was significantly correlated with the ΔPRA/removed-sodium, but not with the removed sodium or removed water by the preceding dialysis. 3) Severe retinal changes were observed in patients with high resting PRA values. In contrast, fundoscopic findings were mild in patients with low resting PRA values. 4) Eleveted resting PRA values were obtained in younger subjects under 29 years of age, while the PEA levels were very low in patients of advanced ages (over 60 years). The latter showed low levels of ΔPRA/removed-sodium. 5) Though the ratios of ΔPRA/removed-sodium were very low in patients under hemodialysis for over 3 years, the resting PRA levels did not decrease with the duration of dialysis treatment, because renin secretion was stimulated strongly by the excessive removal of sodium and water in these later periods of hemodialysis. 6) With regard to the post-dialysis PRA, low renin levels were found in 6.8 per cent of patients, normal in 55.9 per cent, and high in 37.3 per cent. Post-dialysis PEAS were significantly correlated with the pre-dialysis PRAs and the ΔPRA/removed-sodium. From these results, it may be concluded that high PRA is a risk factor producing the hypertensive complications and ΔPRA/removed-sodium is a most important factor controlling the levels of PRAs (pre-dialysis PRA and post-dialysis PRA). Furthermore, age, removed sodium, removed water and the duration of dialysis also might be concerned with the secretion of renin.