In vitro effects of sera from children with acute liver failure on metabolic and synthetic activity of cryopreserved human hepatocytes

Role of ox-PAPCs in the differentiation of mesenchymal stem cells (MSCs) and Runx2 and PPARγ2 expression in MSCs-like of osteoporotic patients

Background

Mesenchymal stem cells (MSCs) can differentiate into osteoblasts and adipocytes and conditions causing bone loss may induce a switch from the osteoblast to adipocyte lineage. In addition, the expression of Runx2 and the PPARγ2 transcription factor genes is essential for cellular commitment to an osteogenic and adipogenic differentiation, respectively.

Modified lipoproteins derived from the oxidation of arachidonate-containing phospholipids (ox-PAPCs: POVPC, PGPC and PEIPC) are considered important factors in atherogenesis.

Methodology

We investigated the effect of ox-PAPCs on osteogenesis and adipogenesis in human mesenchymal stem cells (hMSCs). In particular, we analyzed the transcription factor Runx2 and the PPARγ2 gene expression during osteogenic and adipogenic differentiation in absence and in presence of ox-PAPCs. We also analyzed gene expression level in a panel of osteoblastic and adipogenic differentiation markers.

In addition, as circulating blood cells can be used as a “sentinel” that responds to changes in the macro- or micro-environment, we analyzed the Runx2 and the PPARγ2 gene expression in MSCs-like and ox-PAPC levels in serum of osteoporotic patients (OPs). Finally, we examined the effects of sera obtained from OPs in hMSCs comparing the results with age-matched normal donors (NDs).

Principal findings

Quantitative RT-PCR demonstrated that ox-PAPCs enhanced PPARγ2 and adipogenic gene expression and reduced Runx2 and osteoblast differentiation marker gene expression in differentiating hMSCs. In OPs, ox-PAPC levels and PPARγ2 expression were higher than in NDs, whereas Runx2 was lower than in ND circulant MSCs-like.

Conclusions

Ox-PAPCs affect the osteogenic differentiation by promoting adipogenic differentiation and this effect may appear involved in bone loss in OPs.

Protective effects of ACLF sera on metabolic functions and proliferation of hepatocytes co-cultured with bone marrow MSCs in vitro

AIM: To investigate whether the function of hepatocytes co-cultured with bone marrow mesenchymal stem cells (MSCs) could be maintained in serum from acute-on-chronic liver failure (ACLF) patients.

METHODS: Hepatocyte supportive functions and cytotoxicity of sera from 18 patients with viral hepatitis B-induced ACLF and 18 healthy volunteers were evaluated for porcine hepatocytes co-cultured with MSCs and hepatocyte mono-layered culture, respectively. Chemokine profile was also examined for the normal serum and liver failure serum.

RESULTS: Hepatocyte growth factor (HGF) and Tumor necrosis factor; tumor necrosis factor (TNF)-α were remarkably elevated in response to ACLF while epidermal growth factor (EGF) and VEGF levels were significantly decreased. Liver failure serum samples induced a higher detachment rate, lower viability and decreased liver support functions in the homo-hepatocyte culture. Hepatocytes co-cultured with MSCs could tolerate the cytotoxicity of the serum from ACLF patients and had similar liver support functions compared with the hepatocytes cultured with healthy human serum in vitro. In addition, co-cultured hepatocytes maintained a proliferative capability despite of the insult from liver failure serum.

CONCLUSION: ACLF serum does not impair the cell morphology, viability, proliferation and overall metabolic capacities of hepatocyte co-cultured with MSCs in vitro.

Human primary cultured hepatic stellate cells can be cryopreserved

We compared the morphological and functional characteristics of cultured unfrozen hepatic stellate cells (HSCs) and cryopreserved HSCs obtained from human livers. We used liver tissues obtained by surgical resection from patients with metastatic liver cancer or with hepatocellular carcinoma. HSCs were isolated and allowed to spread in culture. Comparison of morphological and functional features between the unfrozen HSCs and cryopreserved HSCs was performed at each passage using the following techniques: light microscopy, immunohistochemistry, cell growth curve, metallothionein (MTT) assay, and PI staining, Western blot, real-time polymerase chain reaction (PCR), and gene expression analysis using microarrays. The purity of HSCs was more than 90% in all passages. alpha-Smooth muscle actin (SMA-)positive HSCs gradually increased in successive passages, and the positive cell rate and rate of increase in cell number were similar in both groups. Expression of platelet-derived growth factor (PDGF) receptor, transforming growth factor (TGF)-beta receptor, and alpha-SMA mRNAs and protein was similar during each passage in the two groups. Gene expression was nearly identical at each passage in unfrozen and frozen/thawed samples obtained from the same patient. In conclusion, an adequate protocol for the cryopreservation of human primary cultured HSCs could be established.