Long-term dietary nitrate supplementation does not reduce renal cyst growth in experimental autosomal dominant polycystic kidney disease

Jennifer Q J Zhang; Sayanthooran Saravanabavan; Kai Man Cheng; Aarya Raghubanshi; Ashley N Chandra; Alexandra Munt; Benjamin Rayner; Yunjia Zhang; Katrina Chau; Annette T Y Wong; Gopala K Rangan

doi:10.1371/journal.pone.0248400

Long-term dietary nitrate supplementation does not reduce renal cyst growth in experimental autosomal dominant polycystic kidney disease

PLoS One. 2021 Apr 22;16(4):e0248400. doi: 10.1371/journal.pone.0248400. eCollection 2021.

Authors

Jennifer Q J Zhang^{1

2}, Sayanthooran Saravanabavan^{1

2}, Kai Man Cheng^{1

2}, Aarya Raghubanshi^{1

2}, Ashley N Chandra^{1

2}, Alexandra Munt^{1

2}, Benjamin Rayner³, Yunjia Zhang³, Katrina Chau⁴, Annette T Y Wong^{1

2}, Gopala K Rangan^{1

2}

Affiliations

¹ Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Sydney, New South Wales, Australia.
² Department of Renal Medicine, Westmead Hospital, Western Sydney Local Health District, Sydney, New South Wales, Australia.
³ Heart Research Institute, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.
⁴ Department of Renal Medicine and School of Medicine, Western Sydney University at Blacktown Hospital, Sydney, New South Wales, Australia.

Abstract

Augmentation of endogenous nitric oxide (NO) synthesis, either by the classical L-arginine-NO synthase pathway, or the recently discovered entero-salivary nitrate-nitrite-NO system, may slow the progression of autosomal dominant polycystic kidney disease (ADPKD). To test this hypothesis, the expression of NO in human ADPKD cell lines (WT 9-7, WT 9-12), and the effect of L-arginine on an in vitro model of three-dimensional cyst growth using MDCK cells, was examined. In addition, groups of homozygous Pkd1RC/RC mice (a hypomorphic genetic ortholog of ADPKD) received either low, moderate or high dose sodium nitrate (0.1, 1 or 10 mmol/kg/day), or sodium chloride (vehicle; 10 mmol/kg/day), supplemented drinking water from postnatal month 1 to 9 (n = 12 per group). In vitro, intracellular NO, as assessed by DAF-2/DA fluorescence, was reduced by >70% in human ADPKD cell lines, and L-arginine and the NO donor, sodium nitroprusside, both attenuated in vitro cyst growth by up to 18%. In contrast, in Pkd1RC/RC mice, sodium nitrate supplementation increased serum nitrate/nitrite levels by ~25-fold in the high dose group (P<0.001), but kidney enlargement and percentage cyst area was not altered, regardless of dose. In conclusion, L-arginine has mild direct efficacy on reducing renal cyst growth in vitro, whereas long-term sodium nitrate supplementation was ineffective in vivo. These data suggest that the bioconversion of dietary nitrate to NO by the entero-salivary pathway may not be sufficient to influence the progression of renal cyst growth in ADPKD.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Cell Line
Cysts / pathology
Cysts / therapy
Dietary Supplements*
Dogs
Female
Humans
Kidney / pathology*
Madin Darby Canine Kidney Cells
Male
Mice
Mice, Inbred C57BL
Nitrates / therapeutic use*
Polycystic Kidney, Autosomal Dominant / pathology*
Polycystic Kidney, Autosomal Dominant / therapy*

Substances

Nitrates
sodium nitrate

Grants and funding

The research was funded by the National Health and Medical Research Council of Australia (Project Grant Nos. 1164128 and 1138533) and PKD Australia (Recipient G.R.). J.Z. is supported by a Research Training Program Stipend from the University of Sydney. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.