Impact of Aging on Urinary Natriuretic Peptides in Nocturia and Nocturnal Polyuria

Abstract

Purpose: The pathophysiology of nocturia and nocturnal polyuria (NP), conditions that become more prevalent with aging, may in part be explained by changes in hormones involved in water homeostasis. The purpose of this study was to analyze the impact of aging on urinary natriuretic peptides in nocturia and NP.Methods: Patients aged ≥18 years completed 24-hour bladder diaries for assessment of nocturia and NP. They were divided into subgroups of ≥65 years old and <65 years old. Urine samples were collected and analyzed for natriuretic peptide (NT-proANP, NT-proBNP, and NT-proCNP) levels. Peptide levels were compared between patients with and without nocturia/NP and within age subgroups; correlation to the NP index (NPi) was determined.Results: Compared to patients without nocturia (N=15), patients with nocturia (N=36) had higher median levels of urinary NT-proANP (15.8 pmol/mmol Cr vs. 10.9 pmol/mmol Cr, P=0.016) and NT-proBNP (6.3 pmol/mmol Cr vs. 4.5 pmol/mmol Cr, P=0.021), but showed no differences in NT-proCNP (2.4 pmol/mmol Cr vs. 2.5 pmol/mmol Cr, P=0.967). Patients ≥65 years old with nocturia had higher NT-proANP (29.8 pmol/mmol Cr vs. 11.0 pmol/mmol Cr, P<0.001) and NT-proBNP (9.6 pmol/mmol Cr vs. 5.0 pmol/mmol Cr, P<0.001) than patients <65 years old. Additionally, patients with NP (N=30) showed higher urinary NT-proANP (19.6 pmol/mmol Cr vs. 10.5 pmol/mmol Cr, P<0.001) and NT-proBNP (6.7 pmol/mmol Cr vs. 4.7 pmol/mmol Cr, P=0.020) compared to patients without NP (N=21). NP patients ≥65 years had higher NT-proANP (29.8 pmol/mmol Cr vs. 12.5 pmol/mmol Cr, P<0.001) and NT-proBNP (9.6 pmol/mmol Cr vs. 4.4 pmol/mmol Cr, P=0.004) than patients <65 years old. NPi positively correlated with urinary NT-proANP (R<sub>S</sub>=0.417, P=0.002) and NT-proBNP (R<sub>S</sub>=0.303, P=0.031), but not with NT-proCNP (R<sub>S</sub>=-0.094, P=0.510).Conclusions: Since urinary NT-proANP and NT-proBNP were greater in aged patients with nocturia and NP, natriuretic peptides may contribute to the pathophysiology of these conditions and further research should aim to explore them as targets for management.

The prevalence and predictive factors of nocturnal polyuria in Japanese patients with nocturia: a multicentral retrospective cohort study

“…Therefore, changes in water/electrolyte-regulating hormones are thought to contribute to increased nocturnal urine volume 13 . Atrial natriuretic peptide (ANP) is also thought to contribute to increased nocturnal urinary output 22 , 23 . Although some reports have found no difference in ANP levels between patients with and without NP 22 , 23 , it has been shown that nocturnal ANP levels are increased in patients with NP and that urinary ANP levels are higher in older adult patients with nocturia and NP 22 , 23 .…”

“…Atrial natriuretic peptide (ANP) is also thought to contribute to increased nocturnal urinary output 22 , 23 . Although some reports have found no difference in ANP levels between patients with and without NP 22 , 23 , it has been shown that nocturnal ANP levels are increased in patients with NP and that urinary ANP levels are higher in older adult patients with nocturia and NP 22 , 23 . These results suggest that physiological changes in the kidneys and related hormonal changes may be associated with the increased prevalence of NP with age.…”

‘Nocturomics’: transition to omics‐driven biomarkers of nocturia, a systematic review and future prospects

“…Finally, melatonin was decreased in two studies. Melatonin is a hormone released exclusively at night and has been shown to synchronise the circadian rhythms and improve the onset, duration, and quality of sleep by being centrally involved in sleep regulation [27,36]. The proposed mechanisms of the association between reduced melatonin and nocturia include sleep disorders and increased functional bladder capacity [19].…”

“…The association between increased BNP/ANP and nocturia has been noted for many years. Natriuretic peptides regulate the circadian rhythm, dilate blood vessels, and cause the kidney to excrete more salt and water by suppressing renin and aldosterone release [26,27]. Studies from the 1990s suggested a relationship between increased natriuretic peptides and nocturia [28].…”

Lower Urinary Tract Symptoms With a View Beyond the Bladder and Prostate

“…Natriuretic peptide (NP) is a hormone regulating water homeostasis and NP is associated with nocturnal polyuria. A study in this issue of INJ showed that aging influences urinary NP in patients with nocturia [ 7 ]. In addition, oxidative stress associated with aging induces cellular senescence, increases oxidative stress, and affects the mitochondrial bioenergetics of the urothelium [ 8 ].…”