Reply to: "Pivotal preclinical trial of the spheroid reservoir bioartificial liver"

Establishment of acute liver failure model in Tibetan miniature pig and verified by dual plasma molecular adsorption system

BACKGROUND

Acute liver failure (ALF) is a severe liver disease with high morbidity and mortality rates. Animal models are important for research on ALF. This study aimed to establish a reproducible, Tibetan miniature pig model of D-galactosamine-induced ALF and verify it using a dual plasma molecular adsorption system (DPMAS).

METHODS

Tibet miniature pigs were randomly divided into four groups (A, B, C, D) after catheterization. D-galactosamine (D-gal) at 0.45, 0.40, 0.35, and 0.35 g/kg body weight, respectively, was injected through the catheter. Group D was treated with DPMAS 48 h after D-gal administration. Vital signs and blood index values were recorded every 12 h after D-gal administration. H&E, TUNEL, Ki67, and Masson staining tests were performed.

RESULTS

After D-gal administration, Tibetan miniature pigs developed different degrees of debilitation, loss of appetite, and jaundice. Survival times of groups A, B, C, and D were 39.7 ± 5.9, 53.0 ± 12.5,61.3 ± 8.1, and 61 ± 7 h, respectively. Blood levels of ALT, AST, TBIL, ammonia, PT, and inflammation factors significantly increased compared with baseline levels in the different groups (Ps < 0.05). Pathological results revealed a clear liver cell necrosis positive correlation with D-gal dose. However, DPMAS did not increase the survival time in ALF, ammonia, or liver cell necrosis.

CONCLUSION

We successfully established a reproducible Tibetan miniature pig model of d-galactosamine-induced ALF, and we believe that a dosage of 0.35 g/kg is optimal.

Fibrosis in tissue engineering and regenerative medicine: treat or trigger?

Fibrosis is a life-threatening pathological condition resulting from a dysfunctional tissue repair process. There is no efficient treatment and organ transplantation is in many cases the only therapeutic option. Here we review tissue engineering and regenerative medicine (TERM) approaches to address fibrosis in the cardiovascular system, the kidney, the lung and the liver. These strategies have great potential to achieve repair or replacement of diseased organs by cell- and material-based therapies. However, paradoxically, they might also trigger fibrosis. Cases of TERM interventions with adverse outcome are also included in this review. Furthermore, we emphasize the fact that, although organ engineering is still in its infancy, the advances in the field are leading to biomedically relevant in vitro models with tremendous potential for disease recapitulation and development of therapies. These human tissue models might have increased predictive power for human drug responses thereby reducing the need for animal testing.

Cold storage of porcine hepatocyte spheroids for spheroid bioartificial liver

BACKGROUND AND AIMS

Cell-based therapies for liver disease such as bioartificial liver rely on a large quantity and high quality of hepatocytes. Cold storage was previously shown to be a better way to preserve the viability and functionality of hepatocytes during transportation rather than freezing, but this was only proved at a lower density of rat hepatocytes spheroids. The purpose of this study was to optimize conditions for cold storage of high density of primary porcine hepatocyte spheroids.

METHODS

Porcine hepatocytes were isolated by a three-step perfusion method; hepatocyte spheroids were formed by a 24 hours rocked culture technique. Hepatocyte cell density was 5 × 10⁶ /mL in 1000 mL spheroid forming medium. Spheroids were then maintained in rocked culture at 37°C (control condition) or cold stored at 4°C for 24, 48 or 72 hours in four different cold storage solutions: histidine-tryptophan-ketoglutarate (HTK) alone; HTK + 1 mM deferoxamine (DEF); HTK + 5 mM N-acetyl-L-cysteine (NAC); and HTK + 1 mM DEF + 5 mM NAC. The viability, ammonia clearance, albumin production, gene expression, and functional activity of cytochrome P450 enzymes were measured after recovery from the cold storage.

RESULTS

In this study, we observed that cold-induced injury was reduced by the addition of the iron chelator. Viability of HTK + DEF group hepatocyte spheroids was increased compared with other cold storage groups (P < 0.05). Performance metrics of porcine hepatocyte spheroids cold stored for 24 hours were similar to those in control conditions. The hepatocyte spheroids in control conditions started to lose their ability to clear ammonia while production of albumin was still active at 48 and 72 hours (P < 0.05). In contrast, the viability and functionality of hepatocyte spheroids including ammonia clearance and albumin secretion were preserved in HTK + DEF group at both 48- and 72-hour time points (P < 0.05).

CONCLUSIONS

The beneficial effects of HTK supplemented with DEF were more obvious after cold storage of high density of porcine hepatocyte spheroids for 72 hours. The porcine hepatocyte spheroids were above the cutoff criteria for use in a spheroid-based bioartificial liver.