High Throughput Proteomic Exploration of Hypothermic Preservation Reveals Active Processes within the Cell Associated with Cold Ischemia Kinetic

The demand for organs to be transplanted increases pressure on procurement centers, to the detriment of organ quality, increasing complications. New preservation protocols are urgently needed, requiring an in-depth understanding of ischemia-reperfusion mechanisms. We performed a proteomic analysis using LC-MS/MS-TOF data analyzed through R software and Cytoscape’s ClueGO application, comparing the proteome of kidney endothelial cells, key cell type, subjected to 3, 6, 12, 19, and 24 h of cold ischemia and 6 h reperfusion. Critical pathways such as energy metabolism, cytoskeleton structure/transport system, and gene transcription/translation were modulated. Important time windows were revealed: a—during the first 3 h, central proteins were upregulated within these pathways; b—the majority of these upregulations were maintained until 12 h cold ischemia time (CIT); c—after that time, the overall decrease in protein expression was observed; d—at reperfusion, proteins expressed in response to cold ischemia were all downregulated. This shows that cold ischemia is not a simple slowing down of metabolism, as deep changes take place within the proteome on major pathways. Time-sensitive expression of key protein reveals possible quality biomarkers as well as potential targets for new strategies to maintain or optimize organ quality.

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Characterizing Autophagy in the Cold Ischemic Injury of Small Bowel Grafts: Evidence from Rat Jejunum

Metabolites ◽

10.3390/metabo11060396 ◽

2021 ◽

Vol 11 (6) ◽

pp. 396

Author(s):

Ibitamuno Caleb ◽

Luca Erlitz ◽

Vivien Telek ◽

Mónika Vecsernyés ◽

György Sétáló ◽

...

Keyword(s):

Cold Storage ◽

Ischemia Reperfusion ◽

Ischemic Injury ◽

Degradation Pathway ◽

Metabolic Adaptation ◽

Cold Ischemia ◽

Cold Preservation ◽

Opposite Trend ◽

Preservation Injury ◽

Apoptotic Damage

Cold ischemic injury to the intestine during preservation remains an unresolved issue in transplantation medicine. Autophagy, a cytoplasmic protein degradation pathway, is essential for metabolic adaptation to starvation, hypoxia, and ischemia. It has been implicated in the cold ischemia (CI) of other transplantable organs. This study determines the changes in intestinal autophagy evoked by cold storage and explores the effects of autophagy on ischemic grafts. Cold preservation was simulated by placing the small intestines of Wistar rats in an IGL-1 (Institute George Lopez) solution at 4 °C for varying periods (3, 6, 9, and 12 h). The extent of graft preservation injury (mucosal and cellular injury) and changes in autophagy were measured after each CI time. Subsequently, we determined the differences in apoptosis and preservation injury after activating autophagy with rapamycin or inhibiting it with 3-methyladenine. The results revealed that ischemic injury and autophagy were induced by cold storage. Autophagy peaked at 3 h and subsequently declined. After 12 h of storage, autophagic expression was reduced significantly. Additionally, enhanced intestinal autophagy by rapamycin was associated with less tissue, cellular, and apoptotic damage during and after the 12-h long preservation. After reperfusion, grafts with enhanced autophagy still presented with less injury. Inhibiting autophagy exhibited the opposite trend. These findings demonstrate intestinal autophagy changes in cold preservation. Furthermore, enhanced autophagy was protective against cold ischemia–reperfusion damage of the small bowels.

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Transplantation-Induced Ischemia-Reperfusion Injury Modulates Antigen Presentation by Donor Renal CD11c+F4/80+ Macrophages through IL-1R8 Regulation

Journal of the American Society of Nephrology ◽

10.1681/asn.2019080778 ◽

2020 ◽

Vol 31 (3) ◽

pp. 517-531 ◽

Cited By ~ 1

Author(s):

Sistiana Aiello ◽

Manuel Alfredo Podestà ◽

Pamela Y. Rodriguez-Ordonez ◽

Francesca Pezzuto ◽

Nadia Azzollini ◽

...

Keyword(s):

Reperfusion Injury ◽

Antigen Presentation ◽

Kidney Transplant ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Cold Ischemia ◽

Reversible Ischemia ◽

Antigen Presenting

BackgroundIn donor kidneys subjected to ischemia-reperfusion injury during kidney transplant, phagocytes coexpressing the F4/80 and CD11c molecules mediate proinflammatory responses and trigger adaptive immunity in transplantation through antigen presentation. After injury, however, resident renal macrophages coexpressing these surface markers acquire a proreparative phenotype, which is pivotal in controlling inflammation and fibrosis. No data are currently available regarding the effects of transplant-induced ischemia-reperfusion injury on the ability of donor-derived resident renal macrophages to act as professional antigen-presenting cells.MethodsWe evaluated the phenotype and function of intragraft CD11c+F4/80+ renal macrophages after cold ischemia. We also assessed the modifications of donor renal macrophages after reversible ischemia-reperfusion injury in a mouse model of congeneic renal transplantation. To investigate the role played by IL-1R8, we conducted in vitro and in vivo studies comparing cells and grafts from wild-type and IL-R8–deficient donors.ResultsCold ischemia and reversible ischemia-reperfusion injury dampened antigen presentation by renal macrophages, skewed their polarization toward the M2 phenotype, and increased surface expression of IL-1R8, diminishing activation mediated by toll-like receptor 4. Ischemic IL-1R8–deficient donor renal macrophages acquired an M1 phenotype, effectively induced IFNγ and IL-17 responses, and failed to orchestrate tissue repair, resulting in severe graft fibrosis and aberrant humoral immune responses.ConclusionsIL-1R8 is a key regulator of donor renal macrophage functions after ischemia-reperfusion injury, crucial to guiding the phenotype and antigen-presenting role of these cells. It may therefore represent an intriguing pathway to explore with respect to modulating responses against autoantigens and alloantigens after kidney transplant.

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APPLICATION OF WEIGHTING WINDOWS FOR SPECTRAL DENSITY ESTIMATION

10.34220/mamsp_71-77 ◽

2021 ◽

Author(s):

Vera Meerson ◽

O. Khorolsky

Keyword(s):

Fourier Transform ◽

Correlation Function ◽

Spectral Density ◽

Density Estimation ◽

Time Windows ◽

Spectral Density Estimation ◽

Important Time

The article discusses the application of some of the most important time windows for spectral density estimation determined by the correlogram method (from correlation function) and the periodogram method (from direct fourier transform).

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