Agonists of peroxisome proliferator-activated receptor (PPAR)-␥ have been shown to reduce tumor necrosis factor-␣ (TNF-␣)-induced insulin resistance. On the other hand, sensitization of Kupffer cells to lipopolysaccharide (LPS) and their production of TNF-␣ are critical for progression of alcoholic liver injury. This study was intended to determine whether pioglitazone, a PPAR-␥ agonist, could prevent alcohol-induced liver injury. Rats were given ethanol (5 g/kg b.wt.) and pioglitazone (500 g/kg) once every 24 h intragastrically. Ethanol for 8 weeks caused pronounced steatosis, necrosis, and inflammation in the liver. These pathological parameters were diminished greatly by pioglitazone. Kupffer cells were sensitized to LPS after ethanol for 4 weeks as evidenced by aggravation of liver pathology induced by LPS (5 mg/kg) and enhancement of LPS (100 ng/ml)-induced intracellular Ca 2ϩ concentration elevation in Kupffer cells. The parameters were diminished by treatment with pioglitazone. LPS-induced TNF-␣ production by Kupffer cells from the 4-week ethanol group was 3 to 4 times higher than control. This increase was blunted by 70% with pioglitazone. Gut permeability was 10-fold higher in the 4-week ethanol group, and pioglitazone treatment did not change the value. Inclusion of TNF-␣ in culture media of Kupffer cells enhanced CD14 expression, LPS-induced intracellular Ca 2ϩ concentration response, and production of TNF-␣. These results indicate that pioglitazone prevents alcoholic liver injury through abrogation of Kupffer cell sensitization to LPS.
Curdlan dissolved in aqueous sodium hydroxide was dialyzed to aqueous calcium chloride to form a gel. Transparent and turbid concentric layers observed in the gel cross section perpendicular to the long axis of the dialysis tube were identified as liquid crystalline gels with refractive index gradient and amorphous gels, respectively. The thickness of each layer was proportional to the diameter of the dialysis tube, and the gelation proceeded in proportion to the root of time. The unique pattern formation was attributed to the change of curdlan conformation and calcium-induced cross-linking resulting from a diffusion of calcium cations and hydroxide anions through the dialysis tube. It is suggested that the orderedness of the curdlan molecules decreases by the increase of the curvature of the concentric liquid crystal layers as the layer comes toward the center of the dialysis tube.
This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Hidekazu Tsukamoto and Yoshiyuki Takei. The presentations were (1) Tribute to Professor Rajendar K. Chawla, by Craig J. McClain; (2) Dysregulated TNF signaling in alcoholic liver disease, by Craig J. McClain, S. Joshi‐Barve, D. Hill, J Schmidt, I. Deaciuc, and S. Barve; (3) The role of mitochondria in ethanol‐mediated sensitization of the liver, by Anna Colell, Carmen Garcia‐Ruiz, Neil Kaplowitz, and Jose C. Fernandez‐Checa; (4) A peroxisome proliferator (bezafibrate) can prevent superoxide anion release into hepatic sinusoid after acute ethanol administration, by Hirokazu Yokoyama, Yukishige Okamura, Yuji Nakamura, and Hiromasa Ishii; (5) S‐adenosylmethionine affects tumor necrosis factor‐α gene expression in macrophages, by Rajendar K. Chawla, S. Barve, S. Joshi‐Barve, W. Watson, W. Nelson, and C. McClain; (6) Iron, retinoic acid and hepatic macrophage TNFα gene expression in ALD, by Hidekazu Tsukamoto, Min Lin, Mitsuru Ohata, and Kenta Motomura; and (7) Role of Kupffer cells and gut‐derived endotoxin in alcoholic liver injury, by N. Enomoto, K. Ikejima, T. Kitamura, H. Oide, Y. Takei, M. Hirose, B. U. Bradford, C. A. Rivera, H. Kono, S. Peter, S. Yamashina, A. Konno, M. Ishikawa, H. Shimizu, N. Sato, and R. Thurman.
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