Kidney Week

Abstract: SA-PO300

Controls but Not Patients with Calcium Nephrolithiasis Secrete Less Urinary Uromodulin After Salt Loading

Session Information

• Bone and Mineral Metabolism: Stones, Calcifications, Case Reports
  November 04, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 502 Bone and Mineral Metabolism: Clinical

Authors

• Bani Hani, Salar, The University of Texas Southwestern Medical Center, Dallas, Texas, United States

Salar Bani Hani,

• Wolf, Matthias Tilmann, The University of Texas Southwestern Medical Center, Dallas, Texas, United States

Matthias Tilmann Wolf,

• Sakhaee, Khashayar, The University of Texas Southwestern Medical Center, Dallas, Texas, United States

Khashayar Sakhaee,

Background

Calcium is the most common constituent of kidney stones. Uromodulin (UMOD) enhances TRPV5 membrane abundance increasing renal Ca²⁺ absorption thus reducing hypercalciuria. UMOD stimulates Na⁺absorption via NKCC2 causing hypertension. High salt intake is also risk factor for nephrolithiasis. We hypothesize that a higher urinary UMOD secretion with a high salt diet compensates for the higher stone risk by improving hypercalciuria.

Methods

This is a prospective, randomized, cross-over study. Stone-formers and controls were randomized to a control or a high salt diet for 2 days. After washout, the participants received the diet they were not exposed to previously. After each diet, we obtained 24-hour urine and fasting serum studies.

Results

At baseline, there was no significant difference for urinary UMOD secretion between stone-formers and controls. In contrast to our hypothesis, we found that urinary UMOD secretion was significantly reduced after the salt load in controls but not in stone-formers.

Conclusion

There was no lower baseline urine UMOD level in stone-formers. After salt loading, we show lower urinary UMOD secretion in controls but not in stone-formers. As UMOD enhances NKCC2 contributing to hypertension, acute downregulation of UMOD after a salt loading makes physiologically sense.

Salt-loading reduces uUMOD in controls only (P<0.05).

Baseline.