Mesenchymal stromal cells engineered to produce IGF-I ameliorate liver fibrosis with incuction of hepatic regeneration in mice

FIORE EJ; BAYO FINA JM; GARCÍA M; MALVICINI M; LLOYD R; PICCIONI F; RIZZO M; PEIXOTO E; SOLA MB; ATORRASAGASTI C; ALANIZ L; PRIETO J; AQUINO JB; MAZZOLINI G

Vancouver

Congreso; 12th Annual Meeting - International Society for Stem Cell Research; 2014

ISSCR

Liver cirrhosis involves chronic damage and wound healing processes. Mesenchymal stromal cells (MSCs) were previously shown to support tissue repair. Insulin Growth Factor like-I (IGF-I) is known to counteract fibrosis and to induce hepatocytes proliferation and survival. We aimed to evaluate the effects of applying MSCs engineered to produce IGF-I- in an experimental in vivo model of advanced liver fibrosis. Bone marrow MSCs from BALB/c mice were infected with an adenovirus codifying for IGF-I (AdIGF-I) or green fluorescence protein (AdGFP-MSCs). Fibrosis was induced in BALB/c mice by chronic administration of thioacetamide (TAA) during 8 weeks. On week 6, AdIGF-I-MSCs, AdGFP-MSCs or saline were intravenously administered in fibrotic animals which were sacrificed at 1, 3 or 14 days after treatment. The effect of a single cellular dose treatment was compared with that of repeated MSCs applications (3 doses) which were separated by 2 weeks in between. All animals were sacrificed at week 12. In vitro experiments were aimed to evaluate the effect of AdGFP-MSCs or AdIGF-I-MSCs supernatants on CFSC-2G hepatic stellate cells and mouse hepatocyte primary cultures. The application of AdIGF-I-MSCs resulted in a further amelioration of liver fibrosis when compared to AdGFP-MSCs, as shown by morphometric studies. Expression levels of pro-fibrogenic factors in liver samples and in hepatic stellate cells were consistent with AdIGF-I-MSCs exerting anti-fibrotic effects. In the liver, an induction in IGF-I and in hepatocyte growth factor (HGF) expression levels was observed at 1 day and a downregulation in TGFbeta1 and alpha-SMA at 3 days after MSCs application, with higher levels found in samples from AdIGF-I-treated animals. In vitro studies also showed a reduction in HSCs activation and an upregulation in IGF-I and HGF mRNA expression in hepatocytes after incubation with conditioned media from AdIGF-I-MSCs. Interestingly, an induction in PCNA mRNA and protein expression levels was found in the liver of AdIGF-I-treated animals at 1 day after transplantation suggesting the involvement of regenerative mechanisms. Finally, multiple doses of Ad-IGF-I-MSCs further reduced collagen deposition when compared to a single dose treatment. Our data support the experimental application of repeated doses of AdIGF-I-MSCs as therapeutic tools in the long-term treatment of liver fibrosis, and uncover early events likely involved in their anti-fibrotic effect.