Water and Electrolyte Content in Salt-Dependent HYpertension in the SKIn (WHYSKI): Effect of Surgical Cure of Primary Aldosteronism.

 INTRODUCTION: This study will test the hypothesis that primary aldosteronism (PA) involves alterations in Na⁺, K⁺, and water content in the skin that are corrected by adrenalectomy.

Aim and methods: In skin biopsies, we will measure the content of Na⁺, K⁺, water, by physical-chemical methods and the osmotic-stress-responsive transcription factor Tonicity-responsive Enhancer Binding Protein (TonEBP, NFAT5) mRNA copy number by droplet digital PCR, in sex-balanced cohorts of 18 -75-year-old consecutive consenting patients with unilateral and bilateral PA, primary (essential) hypertension, and normotension. Before surgery, the patients with unilateral PA will receive the mineralocorticoid receptor antagonist (MRA) canrenone at doses that correct hypokalemia and high blood pressure values. They will be reassessed in an identical way one month after surgical cure, while off MRA. PA patients not selected for adrenalectomy will similarly be assessed at diagnosis and follow-up while on stable MRA treatment. Since a pilot study showed a direct correlation of dry weight (DW) with skin electrolytes and water content and significant differences of biopsy DW between surgery and follow-up, meaningful comparison of the skin cations and water content and TonEBP mRNA copy number, between specimen obtained at different time points, will require DW- and total mRNA-adjustment, respectively.

Conclusion: This study will provide novel information on the skin Na⁺, K⁺ and water content in PA, the paradigm of salt-dependent hypertension, and novel knowledge on the effect of surgical cure of hyperaldosteronism. The TonEBP-mediated regulation of Na⁺, K⁺ and water content in the skin will also be unveiled.

Trail registry: Trial Registration number: NCT06090617. Date of Registration: 2023-10-19.