Regulatory volume increase of adult human endothelal cells requires extracellular neutral amino acids

O. Bussolati, V. Dall'Asta, R. Sala, G. C. Gazzola, A. Parolari, C. Antona, P. Biglioli

Research output: Contribution to journalArticlepeer-review

Abstract

We study here the response of human saphenous vein endothelial cells (HSVECs) to extracellular hypertonicity. HSVECs were cultured in M199 + 20% FBS, heparin, ECGS and 2 mM glutamine. Sucrose was employed to obtain hypertonic media. Upon incubation in hypertonic medium HSVECs shrank as expected for a perfect osmometer. Complete restoration of cell volume was achieved after 6h of incubation at an external osmolality of 350 mosm/kg but required 12h at 400 mosm/kg. In the absence of glutamine no volume recovery was observed. The osmoprotective effect of glutamine was also exerted by the non metabolizable amino acid analogue MeAIB, a specific substrate of transport system A for neutral amino acids During the incubation in hypertonic media (either in the presence or in the absence of glutamine) a progressive, protein-synthesis dependent increase of the activity of transport system A was detected The cell content of amino acids (but not of potassium) was larger in HSVECs incubated in hypertonic complete media compared with control cells maintained in isotonic medium; on the contrary, no increase in amino acid accumulation was detected in cells incubated in hypertonic glutamine-free medium. Hypertonic treatment of HSVECs cultures caused a significant and progressive cell loss (20% after 12h of incubation at 400 mosm/kg); cell loss was markedly higher (60%) in the absence of glutamine. We conclude that the availability of neutral amino acids substrates of amino acid transport system A in the extracellular medium is essential for both volume recovery and cell preservation under hypertonic conditions.

Original languageEnglish
JournalFASEB Journal
Volume11
Issue number3
Publication statusPublished - 1997

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Cell Biology

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