Ozgur Ozge Sila, Taggart McLean S, Mojoudi Mohammedreza, Pendexter Casie, Kharga Anil, Yeh Heidi, Toner Mehmet, Longchamp Alban, Tessier Shannon N, Uygun Korkut
Massachusetts General Hospital, Harvard Medical School.
Res Sq. 2024 Jul 3:rs.3.rs-4584242. doi: 10.21203/rs.3.rs-4584242/v1.
Preserving organs at subzero temperatures with halted metabolic activity holds the potential to prolong preservation and expand the donor organ pool for transplant. Our group recently introduced partial freezing, a novel approach in high-subzero storage at -15°C, enabling 5 days storage of rodent livers through precise control over ice nucleation and unfrozen fraction. However, increased vascular resistance and tissue edema suggested a need for improvements to extend viable preservation. Here, we describe an optimized partial freezing protocol with key optimizations including increased concentration of propylene glycol to reduce ice recrystallization and maintained osmotic balance through an increase in bovine serum albumin, all while minimizing sheer stress during cryoprotectant unloading with an acclimation period. These approaches ensured the viability during preservation and recovery processes, promoting liver function and ensuring optimal preservation. This was evidenced by increased oxygen consumption, decreased vascular resistance and edema. Ultimately, we show that using the optimized protocol, livers can be stored for 10 days with comparable vascular resistance and lactate levels to 5 days, outperforming the viability of time-matched cold stored livers as the current gold standard. This study represents a significant advancement in expanding organ availability through prolonged preservation and thereby revolutionizing transplant medicine.
在亚零温度下保存器官并停止代谢活动，有可能延长保存时间并扩大用于移植的供体器官库。我们的团队最近引入了部分冷冻技术，这是一种在-15°C的高亚零温度下储存的新方法，通过精确控制冰核形成和未冷冻部分，可实现对啮齿动物肝脏进行5天的储存。然而，血管阻力增加和组织水肿表明需要改进以延长存活保存时间。在此，我们描述了一种优化的部分冷冻方案，其关键优化措施包括提高丙二醇浓度以减少冰重结晶，并通过增加牛血清白蛋白来维持渗透平衡，同时在冷冻保护剂卸载过程中通过适应期将剪切应力降至最低。这些方法确保了保存和恢复过程中的存活率，促进了肝功能并确保了最佳保存效果。这通过耗氧量增加、血管阻力降低和水肿减轻得到了证明。最终，我们表明，使用优化方案，肝脏可以储存10天，其血管阻力和乳酸水平与储存5天时相当，优于作为当前金标准的时间匹配冷保存肝脏的存活率。这项研究代表了通过延长保存时间来扩大器官可用性的重大进展，从而彻底改变移植医学。
