models of liver fibrosis indicate that portal fibroblasts might
During the course of liver fibrogenesis, myofibroblast-like also contribute to MFLC. 6,7 In the course of fibrogenesis, cells (MFLC), mostly derived from hepatic stellate cells, pro-MFLC proliferate 2,3 and synthesize most extracellular matrix liferate and synthesize excessive amounts of extracellular macomponents 8-10 that accumulate in fibrotic liver, [11][12][13] such as trix components. Pentoxifylline (PTX) elicits antiproliferative interstitial and basement membrane (type IV) collagen. In and antifibrogenic effects in human dermal fibroblasts. The addition, synthesis and secretion of gelatinase A (72-kd type aim of this study was to test the effects of PTX on the prolifera-IV collagenase/gelatinase, matrix metalloproteinase-2) is tion and the synthesis of collagen and gelatinase A in cultured markedly increased in MFLC, as compared with quiescent human hepatic MFLC. MFLC were obtained by outgrowth hepatic stellate cells. 14,15 Gelatinase A degrades type IV collafrom human liver explants. PTX markedly reduced serumgen and denaturated interstitial collagens (gelatin), 16 and it driven cell proliferation, as assessed by nuclear autoradiograhas been suggested that enhanced expression of the enzyme phy experiments and measurement of actual cell growth.
could lead to disruption of normal subendothelial liver ma-Growth inhibition was totally reversed after removal of the trix, a process that could favor myofibroblastic transformadrug. PTX also affected collagen synthesis, as measured by tion of hepatic stellate cells. 15 [ 3 H]hydroxyproline incorporation into proteins. Synthesis of Pentoxifylline (PTX) is a xanthine derivative drug that secreted collagen was reduced by 24% and 67% at concentradisplays vasodilating properties for peripheral blood vessels tions of 100 mg/mL and 500 mg/mL, respectively. This was and reduces blood viscosity. 17 The drug is also growth-inhibiassociated with a decrease in type I and III procollagen mestory for human skin fibroblasts and markedly decreases their senger RNA (mRNA), indicating an effect at a pretranslational production of collagen, glycosaminoglycans, and fibroneclevel. In contrast, PTX did not affect either gelatinase A activtin. 18-20 ity released in culture medium or the expression of its specific Given the pivotal role of MFLC in hepatic fibrogenesis, mRNA. In conclusion, PTX exhibits potent antiproliferative there is a tremendous interest in drugs that might limit the and antifibrogenic effects toward hepatic MFLC. These results proliferation and/or matrix component synthesis of these suggest that PTX might have therapeutic implications in cells. We have developed a model of cultured human MFLC chronic liver disease. (HEPATOLOGY 1997;26:315-322.) with the phenotypic characteristics of MFLC found in situ in hepatic fibrosis. 21 We also showed that cultured human Hepatic fibrosis, the main hallmark of chronic liver dis-MFLC proliferate in response to growth factors and syntheease, is characterized by the accumulation of smooth muscle size the extracellular matrix components that accumulate a-actin-positive mesenchymal cells, or myofibroblast-like during chronic liver disease, as well as gelatinase A. 21,22 The cells (MFLC), within the expanding fibrous septa or in the aim of this study was to assess the effect of PTX on the perisinusoidal spaces. 1 Hepatic stellate cells (also called Ito growth of cultured human hepatic MFLC and their capacity cells, perisinusoidal cells, or fat-storing cells) are the main to synthesize collagen and gelatinase A. source of MFLC and play a central role in liver fibrogenesis. [2][3] These cells display a quiescent phenotype in normal MATERIALS AND METHODS liver and acquire myofibroblastic features following acute or Materials chronic liver injury. [2][3][4][5] In addition, studies in experimental Media were obtained from GIBCO BRL (Life Technologies, Cergy-Pontoise, France). All tissue-culture plasticware was from Falcon Plastics (Becton Dickinson, Oxnard, CA), except for 96-well Abbreviations: MFLC, myofibroblast-like cells; PTX, pentoxifylline; MTT, 3-[4,5plates, which were from Costar (Cambridge, MA). Penicillin and dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide; DMEM, Dulbecco's modified streptomycin were from Laboratoires Diamant (Puteaux, France), Eagle medium; cDNA, complementary DNA; G3PDH, glyceraldehyde-3-phosphate deand fungizone from Squibb (Paris, France). Fetal calf serum and hydrogenase; mRNA, messenger RNA.
From Unite Β΄INSERM 99 and De Β΄partement de Pathologie Tissulaire et Cellulaire,