Small animal ex vivo machine perfusion of the liver: A comprehensive literature review

BACKGROUND: Liver transplantation is the only treatment for acute and chronic liver failure, but the global organ shortage has increased reliance on extended criteria donor livers, which are more susceptible to ischemia-reperfusion injury. While static cold storage is standard, these grafts often require improved preservation strategies. AIM: To summarize the current state of small animal liver machine perfusion (MP), highlight variability in protocols, and emphasize the need for standardization to guide future research. METHODS: liver MP. Only English-language animal studies were included, with no restrictions on publication date. Relevant full-text articles were reviewed, and reference lists were screened to ensure completeness. RESULTS: Small animal liver MP provides a cost-effective model to explore dynamic preservation strategies. Rat perfusion studies face challenges including dual-vessel perfusion, maintaining physiological perfusate volumes, and lack of standardized protocols. Open- and closed-circuit setups have distinct advantages and limitations, and experimental designs vary widely across studies. CONCLUSION: This review illustrates the wide variability in small animal liver MP protocols and underscores the urgent need for standardization. Addressing these inconsistencies will enhance reproducibility, facilitate comparison across studies, and support the development of optimized liver preservation strategies.