Effect of Salt Intake and Potassium Supplementation on Serum Renalase Levels in Chinese Adults

Abstract

Renalase, a recently discovered enzyme released by the kidneys, breaks down blood-borne catecholamines and may thus regulate blood pressure (BP). Animal studies have suggested that high levels of dietary salt might reduce blood and kidney renalase levels. We conducted a randomized trial to assess the effects of altered salt and potassium intake on serum renalase levels and the relationship between serum renalase levels and BP in humans.Forty-two subjects (28–65 years of age) were selected from a rural community of northern China. All subjects were sequentially maintained on a low-salt diet for 7 days (3.0 g/day of NaCl), a high-salt diet for additional 7 days (18.0 g/day of NaCl), and a high-salt diet with potassium supplementation for final 7 days (18.0 g/day of NaCl + 4.5 g/day of KCl).Serum renalase levels were significantly higher than baseline levels during the low-salt diet intervention period. Renalase levels decreased with the change from the low-salt to high-salt diet, whereas dietary potassium prevented the decrease in serum renalase induced by the high-salt diet. There was a significant inverse correlation between the serum renalase level and 24-h urinary sodium excretion. No significant correlation was found between the renalase level and BP among the different dietary interventions.The present study indicates that variations in dietary salt intake and potassium supplementation affect the serum renalase concentration in Chinese subjects.

Effect of Salt Intake and Potassium Supplementation on Urinary Renalase and Serum Dopamine Levels in Chinese Adults

“…In addition, increased dietary sodium inhibits renalase protein expression in rats subjected to subtotal nephrectomy, as well as in Dahl salt-sensitive rats [7]. More recently, we found that serum renalase levels increased with a low-salt diet and decreased with a high-salt diet in Chinese subjects [8]. High dietary salt has also been shown to upregulate urinary renalase levels and activity in both 3/4 nephrectomized (3/4nx) and sham rats [9].…”

“…Our previous studies demonstrated that increased potassium intake remarkably alleviated high dietary salt-induced increases in BP [8,13]. Clinical trials have also shown that long-term potassium supplementation may lower the risk of cardiovascular disease [14].…”

Transient changes in serum renalase concentration during long-distance running: The case of an amateur runner under continuous training

“…Human diseases in which the tissue and blood levels of renalase are decreased are essential hypertension, chronic kidney disease, and preeclampsia [4][5][6] . In addition, renalase decreases even when salt intake is high or when there is a lack of potassium intake 7) . The abovementioned diseases or lifestyle habits have hypertensive symptoms as a clinical symptom or health risk.…”

Does Dopamine Mediate Salt-Dependent Urinary Renalase Secretion in Man?

“…This questions the proposed role of renalase in the regulation of blood pressure. Taken together, the results obtained by the Chinese team [9,11] indicate different behavior of serum and urinary renalases under conditions of altered dietary salt supplementation, and suggest the involvement of different mechanisms of salt-dependent regulation of renalase levels in biological body fluids. …”

“…Interestingly, the same Chinese authors found opposite changes in serum renalase levels, which increased in Chinese subjects in response to a low-salt diet and decreased in response to a high-salt diet [11]. This questions the proposed role of renalase in the regulation of blood pressure.…”