A linear relationship between the ex-vivo sodium mediated expression of two sodium regulatory pathways as a surrogate marker of salt sensitivity of blood pressure in exfoliated human renal proximal tubule cells: The virtual renal biopsy

Salt sensitivity (SS) of blood pressure (BP) affects 25% of adults, shares comorbidity with hypertension, and has no convenient diagnostic test. We tested the hypothesis that urine-derived exfoliated renal proximal tubule cells (RPTCs) could diagnose the degree of an individual's SS of BP. Subjects were selected who had their SS of BP determined 5y prior to this study (salt-sensitive: ≥7mm Hg increase in mean arterial pressure (MAP) following transition from a random weekly diet of low (10mmol/day) to high (300mmol/day) sodium (Na+) intake, N=4; inverse salt-sensitive (ISS): ≥7mm Hg increase in MAP transitioning from a high to low Na+ diet, N=3, and salt-resistant (SR):