Fibroblast Na+-Li+ countertransport rate is elevated in essential hypertension

Gianpaolo Zerbini, Francesca Podesta, Giancarla Meregalli, Giacomo Deferrari, Roberto Pontremoli

Research output: Contribution to journalArticlepeer-review

Abstract

Objectives: Elevated erythrocyte Na+-Li+ countertransport (SLC) rates are commonly found in essential hypertension. We have recently shown that human skin fibroblasts functionally express a phloretin-sensitive Na+-H+ exchange (NHE) which may also be similar to erythrocyte SLC because of amiloride-insensitivity. Design and methods: We investigated whether elevations in fibroblast SLC parallel the known elevations in erythrocyte SLC and in cell NHE that characterize essential hypertension. Results: Higher fibroblast SLC rates were found among hypertensive patients (n = 23, median 48.8 nmol Li+/mgprotein per min) than in 19 normotensive individuals of similar age and sex (median 14.8 nmol Li+/mgprotein per min, P = 0.0002). As expected, erythrocyte SLC was elevated in patients with hypertension (median 411 versus 329 μmol/lcell per h, P = 0.0273), but was not quantitatively related to fibroblast SLC. Finally, fibroblast NHE exchange activity was higher in essential hypertension (median Vmax 14.2 versus 7.6 mmol H+/lcell per min, P = 0.002), but was unrelated to fibroblast SLC. Conclusions: These findings extend to human skin fibroblasts the notion of abnormal Li+ transport in essential hypertension, and appear to be in accordance with the hypothesis that fibroblast SLC may be independent of NHE. However, molecular studies will be required to understand whether distinct exchangers and/or regulation mechanisms underlie these dysregulations.

Original languageEnglish
Pages (from-to)1263-1269
Number of pages7
JournalJournal of Hypertension
Volume19
Issue number7
DOIs
Publication statusPublished - 2001

Keywords

  • Essential hypertension
  • Human skin fibroblast
  • Na+-H+ exchange
  • Na+-Li+ countertransport

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology

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