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Hypoxia is an inducer of vasodilator agents in peritoneal macrophages of cirrhotic patients
Author(s) -
CejudoMartín Pilar,
MoralesRuiz Manuel,
Ros Josefa,
Navasa Miguel,
FernándezVaro Guillermo,
Fuster Josep,
Rivera Francisca,
Arroyo Vicente,
Rodés Juan,
Jiménez Wladimiro
Publication year - 2002
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1053/jhep.2002.36371
Subject(s) - hypoxia (environmental) , nitric oxide , endocrinology , medicine , vasodilation , ascites , biology , g alpha subunit , protein subunit , chemistry , biochemistry , organic chemistry , oxygen , gene
The aim of the investigation was to assess whether hypoxia induces the production of endogenous vasoactive peptides in macrophages of cirrhotic patients with ascites because low tissue oxygenation is a relatively frequent event in these patients. Peritoneal macrophages were isolated from ascites, seeded on well plates, and cultured at different times under hypoxic (5% O 2 ) or normoxic conditions (21% O 2 ). Then, accumulation of vasoactive peptides sensitive to hypoxia including endothelin‐1 (ET‐1), vascular endothelial growth factor (VEGF), and adrenomedullin (ADM) was measured. Only VEGF and ADM were constitutively secreted, and hypoxia further stimulated the release of these vasodilator peptides. In concordance, increased messenger RNA (mRNA) levels of VEGF and ADM were found at culturing macrophages in hypoxia. This characteristic response was not observed in circulating monocytes of either cirrhotic patients or healthy subjects. Next the expression of the transcription factor, hypoxia inducible factor 1 (HIF‐1), was analyzed. Expression of HIF‐1α and HIF‐1β messengers and HIF‐1β protein subunit remained unchanged regardless of O 2 tension, whereas HIF‐1α protein subunit was overexpressed under hypoxic conditions. Moreover, conditioned medium from macrophages cultured under hypoxic conditions promoted a larger nitric oxide (NO) release in endothelial cells than that of normoxic macrophages. In conclusion, these data indicate that hypoxia induces the synthesis of VEGF and ADM in macrophages of cirrhotic patients, likely through HIF‐1–enhanced transcriptional activity. These data suggest that a local reduction in O 2 tension could enhance the synthesis of macrophage‐derived vasodilators, thus aggravating the circulatory disturbance of these patients.