The phosphodiesterase III inhibitor olprinone decreases sensitivity of rat Kupffer cells to endotoxin.
BACKGROUND
Sensitivity of Kupffer cells to endotoxin [lipopolysaccharide (LPS)] and overproduction of tumor necrosis factor-alpha (TNF-alpha) are critical for progression of alcoholic liver injury. Therefore, suppression of TNF-alpha should prove useful for treatment of alcoholic liver injury. However, a transient increase of intracellular calcium ([Ca]i) is required for LPS-induced TNF-alpha production by the macrophage cell line. The phosphodiesterase III inhibitor olprinone has been shown to suppress [Ca]i level in vascular smooth muscle cells. Accordingly, the purpose of this study was to determine whether olprinone could prevent sensitization of Kupffer cells to endotoxin.


METHODS
Kupffer cells were isolated by collagenase digestion and differential centrifugation. LPS was added to Kupffer cells 24 hr after incubation with or without olprinone (0.1 micromol/liter). After addition of LPS (10 microg/ml) to culture media, [Ca]i was measured using a fluorescent indicator, fura-2.


RESULTS
LPS increased [Ca]i of Kupffer cells in control rats from basal levels (28 +/- 4 nmol/liter) to 280 +/- 14 nmol/liter. This increase was blunted by olprinone (91 +/- 8 nmol/liter). Similarly, olprinone diminished the LPS (1 microg/ml)-induced TNF-alpha production by Kupffer cells by 30% (2220 +/- 116 vs. 1386 +/- 199 pg/ml; p < 0.05).


CONCLUSIONS
These results indicate that olprinone decreases sensitivity of Kupffer cells to endotoxin.
Department of Gastroenterology, Juntendo University School of Medicine, Tokyo, Japan.
Nobuyuki
N
Enomoto
Yoshiyuki
Y
Takei
Miyoko
M
Hirose
Shunhei
S
Yamashina
Kenichi
K
Ikejima
Tsuneo
T
Kitamura
Nobuhiro
N
Sato
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D004731:Endotoxins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005260:Female; D007093:Imidazoles / Q000494:pharmacology*; D007728:Kupffer Cells / Q000187:drug effects* / Q000201:enzymology*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D011728:Pyridones / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004731:Endotoxins; D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D011728:Pyridones; C059498:olprinone; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3