The Role of Urinary Extracellular Vesicles Sodium Chloride Cotransporter in Subtyping Primary Aldosteronism

Abstract

BackgroundAdrenal venous sampling (AVS) is recognized as the gold standard for subtyping primary aldosteronism (PA), but its invasive nature and technical challenges limit its availability. A recent study reported that sodium chloride cotransporter (NCC) in urinary extracellular vesicles (uEVs) is a promising marker for assessing the biological activity of aldosterone and can be treated as a potential biomarker of PA. The current study was conducted to verify the hypothesis that the expression of NCC and its phosphorylated form (pNCC) in uEVs are different in various subtypes and genotypes of PA and can be used to select AVS candidates.MethodsA total of 50 patients with PA were enrolled in the study. Urinary extracellular vesicles (uEVs) were isolated from spot urine samples using ultracentrifugation. NCC and pNCC expressions were tested in patients diagnosed with PA who underwent AVS. Sanger sequencing of KCNJ5 was performed on DNA extracted from adrenal adenoma.ResultspNCC (1.89 folds, P<.0001) and NCC (1.82 folds, P=0.0002) was more abundant in the uEVs in the high lateralization index (h-LI, ≥ 4) group than in the low LI (l-LI, < 4) group. Carriers of the somatic KCNJ5 mutations, compared with non-carriers, had more abundant pNCC expression (2.16 folds, P=0.0039). Positive correlation between pNCC abundance and plasma aldosterone level was found in this study (R = 0.1220, P = 0.0129).ConclusionsThe expression of pNCC in uEVs in patients with PA with various subtypes and genotypes was different. It can be used as biomarker of AVS for PA subtyping.

Urinary extracellular vesicles carry valuable hints through mRNA for the understanding of endocrine hypertension

“…Interestingly, in those studies that investigated a specific mRNA of uEVs in endocrine hypertension, namely NCC in PA and 11β-HSD2 in AME ( 9 , 15 ), the results were somewhat different from those expected when looking at the specific protein studies. Previous data on uEVs NCC protein demonstrated that patients with PA are characterized by a higher level of NCC and pNCC in comparison to essential hypertensive patients, with a modulation by both mineralocorticoid administration and potassium levels, and a higher abundance in patients with documented monolateral versus bilateral PA disease ( 16 , 17 , 20 , 23 ). Consistent with these findings, one could expect a reflection of the differences in protein abundance in the abundance of the corresponding mRNA, but this did not occur.…”

“…Besides lipids and proteins, uEVs also carry RNA molecules and are secreted from renal epithelial cells into the urine, thus providing access to information about kidney tissue physiology and possibly to kidney-related diseases pathophysiology ( 21 , 22 ). Most studies, however, have focused, on the proteins and non-coding RNA profiles of uEVs and almost all are related to endocrine hypertension referring more specifically to primary aldosteronism (PA) and to apparent mineralocorticoid excess (AME) ( 12 – 14 , 16 , 17 , 19 , 20 , 23 , 24 ).…”

“…Moreover, exogenous mineralocorticoid administration by fludrocortisone was associated with a rapid increase in abundance of NCC and phosphorylated NCC (pNCC), possibly related to the modulation of potassium, that was inversely related to NCC and pNCC ( 17 ). Very recently, pNCC and NCC were demonstrated to be more abundant in PA patients with unilateral disease at the adrenal venous sampling than in patients with the bilateral disease, suggesting a possible use of uEVs NCC protein as a biomarker for PA subtypes ( 20 ).…”

Diabetes with kidney injury may change the abundance and cargo of urinary extracellular vesicles

“…A recent study revealed that the abundance of phosphorylated sodium chloride cotransporter in uEVs was significantly higher (1.89 folds) than that of the controls. Therefore, the protein biomarker of uEVs may be considered as an indicator of adrenal venous sampling ( 44 ). Our results also established the reliability of using uEV protein changes to monitor physiological and pathological responses in diabetic nephropathy.…”

Using human urinary extracellular vesicles to study physiological and pathophysiological states and regulation of the sodium chloride cotransporter

“…The hypokalaemia in patients with primary aldosteronism or Cushing's syndrome may contribute to hypertension through increased Na + reabsorption via enhanced NCC activity. Recently, Kong et al reported that differences in NCC and pNCC in uEVs can be used as biomarker for subtyping of primary aldosteronism and potentially for avoiding the need for adrenal venous sampling (AVS) in differentiating unilateral from bilateral forms (138). The use of uEVs as biomarkers for primary aldosteronism subtyping appears valid; however, uEVs cannot be used to avoid AVS because even if associated to unilateral forms, the side of lateralization cannot be identified.…”