Complement regulation is associated with enhanced cardiac tolerance to prolonged cold preservation

Background/Introduction The limited tolerance of the human heart to cold ischemic preservation remains a major constraint in heart transplantation. Hibernating mammals exhibit remarkable resistance to ischemia and hypothermia, suggesting the presence of intrinsic cardioprotective mechanisms relevant to prolonged cold storage. Purpose This study aimed to elucidate the mechanisms underlying tolerance to prolonged cold preservation in the hearts of a hibernating species using comprehensive multi-omics analyses. Methods Hearts from 25–28-week-old female Syrian hamster (hibernator, n =12) and SD rat (non-hibernator, n =12) were excised and subjected to 24 hours of cold preservation using a standard preservation solution, followed by 1 hour of reperfusion at 37 °C using a Langendroff system. Cardiac function recovery was assessed during reperfusion. Tissue samples collected before preservation, after preservation, and after reperfusion were analyzed using transcriptomic and proteomic approaches. Differential expression was evaluated by two-way analysis of variance with interaction effects, followed by pathway enrichment analyses. Results Following cold preservation and subsequent reperfusion, hearts from hamsters exhibited significantly better functional recovery than those from rats in all parameters (coronary flow, heart rate, LV development pressure, max dP/dt, min dP/dt, and rate pressure product). Multi-omics analyses identified a subset of genes and proteins showing significant time × species interaction effects. Pathway enrichment analyses consistently highlighted regulation of the complement system. Notably, key components involved in complement activation (C3) and inhibition (Cfh and Clu) displayed distinct expression patterns between species. At the transcriptomic level, expression of C3, Cfh, and Clu remained largely unchanged in rats, with Cfh showing a decrease, whereas all three genes were significantly upregulated after reperfusion in hamsters. In contrast, at the proteomic level, C3, Cfh, and Clu were markedly decreased in rats following reperfusion. Although these proteins also showed reductions in hamsters, the magnitude of decrease was significantly attenuated compared with rats. Taken together, these findings suggest a coordinated and species-specific modulation of innate immune responses, particularly complement regulation, during cold preservation and reperfusion in hibernating hearts. Conclusions Hibernating hearts exhibit strong tolerance to prolonged cold preservation with preserved functional recovery. Multi-omics analyses indicate that regulation of the complement system may contribute to this cold preservation tolerance. These findings provide mechanistic insights that may inform the development of novel strategies to extend cardiac preservation time.heart functionmultiomics results