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עמוד בית
Wed, 12.06.24

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February 2010
B. Weiss, I. Barshack, N. Onaca, I. Goldberg, Z. Berkovich, E. Melzer, A. Jonas and R. Reifen

Background: Vitamin A and its derivative retinoic acid regulate various aspects of cell behavior as growth, differentiation, and proliferation. Retinoic acid derivatives have been suggested to play a role in processes such as hepatic regeneration and fibrosis.

Objectives: To evaluate the influence of vitamin A on rat liver epithelial cell proliferation.

Methods: We performed common bile duct ligation in rats that had been subjected to differing vitamin A diets and compared their livers to control rats. Proliferation, apoptosis, and retinoic acid receptors were evaluated by histology and immunohistochemistry in bile duct cells and hepatocytes.

Results: Vitamin A deficiency was found to be associated with enhanced proliferation of bile duct epithelial cells following CBD[1] ligation. The proliferation was manifested by increased numbers of ducts, by aberrant extended ductal morphology, and by elevated numbers of nuclei expressing the proliferation marker Ki67. The amount of vitamin A in the rat diet did not affect detectably ductal cell apoptosis. We observed up-regulated expression of the retinoid X receptor-alpha in the biliary epithelium of vitamin A-deficient rats that had undergone CBD ligation, but not in vitamin A-sufficient rats.

Conclusions: We speculate that the mechanism underlying the ductal proliferation response involves differential expression of RXR[2]-alpha. Our observations suggest that deficiency of vitamin A may exacerbate cholestasis, due to excessive intrahepatic bile duct proliferation.






[1] CBD = common bile duct



[2] RXR = retinoid X receptor


February 2002
Mickey Scheinowitz, PhD, Arkady-Avi Kotlyar, PhD, Shachar Zimand, MD, Ilan Leibovitz, MD, Nira Varda-Bloom, Dan Ohad, Iris Goldberg, PhD, Santiego Engelberg, MD, Nafthali Savion, PhD and Michael Eldar, MD

Background: Previous studies have demonstrated myocardial salvage by basic fibroblast growth factor administration following chronic myocardial ischemia or acute myocardial infarction.

Objectives: To study the effect of bFGF[1] on left ventricular morphometry following coronary occlusion and reperfusion episode in rats.

Methods: bFGF (0.5 mg) or placebo was continuously administered for a period of one week using an implanted osmotic pump. Animals were sacrificed 6 weeks after surgery and myocardial cross-sections were stained with Masson-trichrome and with anti-proliferating cell nuclear antigen antibody.

Results: LV[2] area, LV cavity diameter, LV cavity/wall thickness ratio, and injury size were unchanged compared with control animals. Proliferating endothelial cells were significantly more abundant in injured compared with normal myocardium, but with no differences between animals treated or not treated with bFGF.

Conclusions: One week of systemic bFGF administration following coronary occlusion and reperfusion had no additional effect on LV geometry or cellular proliferation in rats.

________________________

[1]
bFGF = basic fibroblast growth factor

[2] LV = left ventricular

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