Glycocalyx Preservation and NO Production in Fatty Livers—The Protective Role of High Molecular Polyethylene Glycol in Cold Ischemia Injury

Abstract

Improving the protection of marginal liver grafts during static cold storage is a major hurdle to increase the donor pool of organs. The endothelium glycocalyx quality of preservation influences future inflammatory and oxidative responses. One cellular pathway responsible for the formation of nitric oxide by endothelial cells is dependent on the stimulation of proteoglycans present in the glycocalyx. We investigated the impact of the glycocalyx preservation in static cold storage of fatty liver preserved in different preservation solutions on the endothelium-mediated production of NO. Zucker fatty rat livers were preserved 24 h in static cold storage in either Institut Georges Lopez-1 (IGL-1) (n = 10), IGL-0 (i.e., without PEG35) (n = 5) or Histidine-Tryptophan-Ketoglutarate (HTK) (n = 10) preservation solutions before being processed for analysis. For Sham group (n = 5), the fatty livers were immediately analyzed after procurement. The level of transaminases and nitrites/nitrates were measured in the washing perfusate. Glycocalyx proteins expressions, Syndecan-1, glypican-1 and heparan sulfate (HS), were determined in the tissue (ELISA). Steatotic livers preserved 24 h in IGL-1 preservation solution have a significant lower level of transaminases (aspartate aminotransferase (AST), alanine aminotransferase (ALT)) and less histological damages than steatotic livers preserved 24 h with HTK (p = 0.0152). The syndecan-1 is significantly better preserved in IGL-1 group compared to HTK (p < 0.0001) and we observed the same tendency compared to IGL-0. No significant differences were observed with glypican-1. HS expression in HTK group was significantly higher compared to the three other groups. HS level in IGL-1 was even lower than IGL-0 (p = 0.0005) which was similar to Sham group. The better protection of the glycocalyx proteins in IGL-1 group was correlated with a higher production of NO than HTK (p = 0.0055) or IGL-0 (p = 0.0433). IGL-1 protective mechanisms through the formation of NO could be due to its better protective effects on the glycocalyx during SCS compared to other preservation solutions. This beneficial effect could involve the preservation state of syndecan-1 and the internalization of HS.

Polyethylene Glycol 35 as a Perfusate Additive for Mitochondrial and Glycocalyx Protection in HOPE Liver Preservation

“…With these considerations, and in accordance with the observations of Schiefer et al [63], we corroborated that the GCX suffers an alteration during hypothermic preservation [64]. The improved preservation of the GCX, supported by our data, correlate with an increased presence of NO in the group where livers were preserved in 24 h SCS with a solution containing PEG35 (IGL-1) as compared to one without oncotic agent (HTK).…”

“…One of the main consequences of an adequate functioning of the GCX mechanotransduction is NO production [60]; therefore, mitigating GCX destruction is a necessary step to regulating NO production in order to maintain a good perfusion and an adequate preservation [60]. In previously reported studies, we demonstrated the relevance of NO induced by PEG35, which correlated with an enhanced preservation of the GCX during static preservation when comparing two solutions, IGL-1 and HTK [64].…”

“…The improved preservation of the GCX, supported by our data, correlate with an increased presence of NO in the group where livers were preserved in 24 h SCS with a solution containing PEG35 (IGL-1) as compared to one without oncotic agent (HTK). In this case, the protective benefits of IGL-1 were presumably associated with the presence of the oncotic agent PEG35 [64].…”

Aldehyde Dehydrogenase 2 (ALDH2) in Rat Fatty Liver Cold Ischemia Injury

“…This theory is supported by the fact that the presence or absence of PEG35-rinse solutions for liver grafts protects against mitochondrial damage [ 41 , 42 ], and by the comparison of IGL-1 (with PEG35) vs. HTK (without PEG35) in fatty liver graft preservation [ 43 ]. Moreover, recent preliminary research comparing IGL-1 with the same solution without oncotic agent PEG35 (IGL-0) found that the absence of PEG35 significantly reduced the fatty liver graft protection against ischemic insult after 24 h at 4 °C [ 44 ].…”

Organ Preservation into the 2020s: The Era of Dynamic Intervention

“…Steatotic livers had a reduced level of eNOS activity and NO production as well as decreased Kruppel-like factor 2 expression under subnormothermic perfusion [68]. In a recent study of steatotic rat liver preservation, it was shown that Institut Georges Lopez-1 (IGL-1®) preservation solution produced less GCX injury over HTK, which was associated with significantly reduced hepatocyte damage and higher NO production after 24 h of SCS [69]. Therapeutic strategies in GCX protection during organ preservation could potentially enhance the organ viability of marginal donors and reduce the severity of IRI.…”