Repopulation of the fibrotic/cirrhotic rat liver by transplanted hepatic stem/progenitor cells and mature hepatocytes

Abstract

Background & Aim Considerable progress has been made in developing anti-fibrotic agents and other strategies to treat liver fibrosis; however, significant long-term restoration of functional liver mass has not yet been achieved. Therefore, we investigated whether transplanted hepatic stem/progenitor cells can effectively repopulate the liver with advanced fibrosis/cirrhosis. Methods Stem/progenitor cells derived from fetal livers or mature hepatocytes from DPPIV+ F344 rats were transplanted into DPPIV− rats with thioacetamide (TAA)-induced fibrosis/cirrhosis; rats were sacrificed 1, 2, or 4 months later. Liver tissues were analyzed by histochemistry, hydroxyproline determination, RT-PCR, and immunohistochemistry. Results After chronic TAA administration, DPPIV− F344 rats exhibited progressive fibrosis, cirrhosis and severe hepatocyte damage. Besides stellate cell activation, increased numbers of stem/progenitor cells (Dlk-1+, AFP+, CD133+, Sox-9+, FoxJ1+) were observed. In conjunction with partial hepatectomy (PH), transplanted stem/progenitor cells engrafted, proliferated competitively compared to host hepatocytes, differentiated into hepatocytic and biliary epithelial cells, and generated new liver mass with extensive long-term liver repopulation (40.8 ± 10.3%). Remarkably, more than 20% liver repopulation was achieved in the absence of PH, associated with reduced fibrogenic activity (e.g., expression of α-SMA, PDGFRβ, desmin, vimentin, TIMP1) and fibrosis (reduced collagen). Furthermore, hepatocytes can also replace liver mass with advanced fibrosis/cirrhosis, but to a lesser extent than FLSPCs. Conclusions This study is a Proof of Principle demonstration that transplanted epithelial stem/progenitor cells can restore injured parenchyma in a liver environment with advanced fibrosis/cirrhosis and exhibit anti-fibrotic effects.

Cellular Therapy for Liver Disease

“…34 Transplant of LSPCs from various sources has been accomplished via intrasplenic injection or infusion into a peripheral vein or the portal vein, with the idea that they may augment the impaired regeneration seen in the setting of chronic liver disease and promote reverse remodeling of fibrosis. 35 Engraftment and repopulation have been observed, even in the setting of fibrosis, 27,36 but generally, a regenerative stimulus such as partial hepatectomy or retrorsine injection is required for optimal engraftment. Although some studies suggest reduced fibrosis after LSPC transplant, 36 there have also been descriptions of a severe fibrogenic response that is, in fact, driven by the activation of the hepatic progenitor compartment.…”

“…35 Engraftment and repopulation have been observed, even in the setting of fibrosis, 27,36 but generally, a regenerative stimulus such as partial hepatectomy or retrorsine injection is required for optimal engraftment. Although some studies suggest reduced fibrosis after LSPC transplant, 36 there have also been descriptions of a severe fibrogenic response that is, in fact, driven by the activation of the hepatic progenitor compartment. 37 Furthermore, as in hepatocyte transplant, adult LSPCs are available only in limited numbers, and there are ethical constraints on the use of human fetal LSPCs.…”

Biliary fibrosis drives liver repopulation and phenotype transition of transplanted hepatocytes

“…However, we recently demonstrated that the injury inherent in severe liver disease can also drive repopulation by transplanted cells without additional treatment. In these experiments, we studied advanced cirrhosis induced by the hepatotoxin thioacetamide (TAA) and observed engrafted and repopulating cell clusters at 2 months after transplantation without the additional stimulus of PH (13). …”

“…As in our previous studies (6, 13), the experiments utilized transplantation of dipeptidyl-peptidase IV-positive (DPPIV + ) donor cells into allogeneic DPPIV − host rats, but because BDL made the portal vein inaccessible, cell transplantation was carried out via intrasplenic injection. The experiments indeed demonstrated that biliary fibrosis induces hepatocyte repopulation, but surprisingly, they also showed striking and rapid transition of hepatocytes to cholangiocyte-like cells in both liver and spleen.…”

<b>Tratamento com células derivadas do fígado embrionário retarda a progressão da fibrose hepática em ratos</b>

“…Entretanto como nos animais tratados houve uma maior expressão desse marcador, os resultados referentes e a morfometria e à quantificação demonstraram maior expressão deste marcador nos animais do grupo G3 em relação ao grupo G2, confirmando a hipótese de maior estimulo a regeneração tecidual, considerando o potencial regenerativo das células (PAYUSHINA et al, 2013;PATIL et al, 2014) As células derivadas do fígado embrionário de ratos com 14,5 dias de gestação demonstraram as características esperadas para terapia, uma vez que tais células apresentaram marcadores de células progenitoras hepáticas tais como CD 44, CD 117(c-kit), Nestin (OERTEL, 2011;BIN et al, 2012;EXPERIMENTAL, 2013;GONGH et al, 2013), assim como CK 18, marcador de hepatoblastos precursores de hepatócitos (FIEGEL et al, 2006;SEMERARO et al, 2012;HABEEB et al, 2015). Quanto ao marcador de colangiocitos, CK 7 (CANTZ; MANNS; OTT, 2008;OERTEL et al, 2008;GONGH et al, 2013), este também foi expresso, confirmando assim o seu bipotencial de diferenciação com sugerem os trabalhos de (OERTEL, 2011;BIN et al, 2012;YOVCHEV et al, 2014).…”