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Transplantation Proceedings 2021One of the cornerstone research models used in our laboratories is the induction of ischemic injury through cold ischemia followed by warm ischemia to donor kidneys to...
One of the cornerstone research models used in our laboratories is the induction of ischemic injury through cold ischemia followed by warm ischemia to donor kidneys to mimic the clinical realities of transplantation. The experimental design of the present study included bilateral nephrectomies on the day of syngeneic kidney transplant, with serum creatinine measured 24 hours postoperatively to measure acute function. Cold ischemia time in these experiments was always 30 minutes, and warm ischemia time was not standardized but always recorded. It became apparent that some transplanted kidneys that should have displayed injury were producing close to normal serum creatinine levels on postoperative day 1. In reviewing our data, we found a potential correlation between warm ischemia time and serum creatinine, in particular a significant proportion of low serum creatinine results (0.48 ± 0.26 mg/dL vs 1.99 ± 1.11 mg/dL; P < .05) was associated with warm ischemia times that were significantly shorter than our historical average (29.2 ± 2.7 min vs 35.7 ± 2.2 min; P < .05). The kidneys with lower serum creatinine also displayed lower apoptosis and brush border injury scores and fewer tubular casts. Therefore, we concluded that establishing a minimum warm ischemia time was just as important as standardized cold ischemia time to ensure consistent injury in this model.
Topics: Animals; Cold Ischemia; Creatinine; Disease Models, Animal; Ischemia; Kidney; Kidney Transplantation; Male; Mice; Warm Ischemia
PubMed: 33168203
DOI: 10.1016/j.transproceed.2020.08.010 -
Biopreservation and Biobanking Aug 2021High-quality RNA extraction from tissue samples is of key importance for scientific research and translational medicine. Tissue collection and preparation may affect...
High-quality RNA extraction from tissue samples is of key importance for scientific research and translational medicine. Tissue collection and preparation may affect RNA quality. In this study, we investigated effects of warm ischemia time, cryopreservation, and grinding methods on RNA quality. Total RNA was extracted from mouse kidney tissues with warm ischemia times of 0, 30, 60, 90, and 120 minutes. Half of the tissues were used to extract RNA immediately, while the others were cryopreserved in the vapor phase of liquid nitrogen for 6 months before RNA extraction. A mortar, homogenizer, and tissue lyser were used to grind tissues. RNA was extracted by TRIzol, and RNA integrity was assessed by the RNA integrity number (RIN) value. For fresh tissues and frozen tissues with warm ischemia time within 60 minutes, RIN values were above 7.0 and remained above 6.0 with warm ischemia time within 120 minutes. For the same warm ischemia time, RIN values of frozen tissues were slightly lower than those of fresh tissues. No significant RIN value alterations were observed among grinding methods, but for RNA extraction efficiency, a mortar was much less efficient than the homogenizer or tissue lyser. For frozen tissues, RNA tended to degrade within 8 minutes at room temperature. Mouse kidney tissues with a warm ischemia time within 120 minutes are suitable for general RNA-related research. For tissues with a warm ischemia time within 60 minutes, cryopreservation may not affect RNA quality. The duration of frozen tissues held at room temperature before grinding affects the integrity of RNA, while grinding methods do not affect RNA integrity.
Topics: Animals; Cryopreservation; Kidney; Mice; RNA; Tissue Banks; Warm Ischemia
PubMed: 33577406
DOI: 10.1089/bio.2020.0129 -
American Journal of Transplantation :... Nov 2021
Topics: Cell Count; Cell Separation; Humans; Islets of Langerhans; Islets of Langerhans Transplantation; Warm Ischemia
PubMed: 34008319
DOI: 10.1111/ajt.16691 -
Urology Dec 2014To assess renal functional deterioration after partial nephrectomy with warm and cold ischemia using (99m)Tc-mercaptoacetyltriglycine ((99m)Tc-MAG3) renal scintigraphy... (Comparative Study)
Comparative Study
OBJECTIVE
To assess renal functional deterioration after partial nephrectomy with warm and cold ischemia using (99m)Tc-mercaptoacetyltriglycine ((99m)Tc-MAG3) renal scintigraphy parameters.
METHODS
Open partial nephrectomy was performed in 59 patients with warm ischemia and 64 patients with cold ischemia. (99m)Tc-MAG3 renal scintigraphy was performed and effective renal plasma flow was calculated to evaluate split renal function. In addition, regional (99m)Tc-MAG3 uptake was analyzed in the surgically unaffected parts to evaluate ischemic damage.
RESULTS
The mean tumor size in the warm and cold ischemia groups was 2.9 and 3.2 cm, respectively, and the mean ischemic time was 24.2 minutes (range, 8-46 minutes) and 26.7 min (range, 8-58 minutes), respectively. One week after surgery, effective renal plasma flow in the operated kidney decreased to 66.2% (from 160.2 to 105.4 mL/min/1.73 m(2)) in the warm ischemia group and to 77.4% (from 152.3 to 116.6 mL/min/1.73 m(2)) in the cold ischemia group. Regional (99m)Tc-MAG3 uptake changed to 89.2% of baseline in the warm ischemia group and 101.5% of baseline in the cold ischemia group. When the ischemic time was ≥ 25 minutes, regional (99m)Tc-MAG3 uptake in the warm ischemia group did not recover to the baseline level at 6 months. Multiple regression analyses demonstrated a significant correlation between ischemic time and the decrease in regional (99m)Tc-MAG3 uptake in the warm ischemia group, but not in the cold ischemia group.
CONCLUSION
Warm ischemia for ≥ 25 minutes caused long lasting diffuse damage throughout the operated kidney, whereas cold ischemia for up to 58 minutes prevented ischemic injury to the renal remnant.
Topics: Chi-Square Distribution; Cohort Studies; Cold Ischemia; Female; Follow-Up Studies; Glomerular Filtration Rate; Humans; Kidney Function Tests; Kidney Neoplasms; Male; Multivariate Analysis; Nephrectomy; Postoperative Care; Postoperative Complications; Radionuclide Imaging; Regression Analysis; Retrospective Studies; Technetium Tc 99m Mertiatide; Time Factors; Treatment Outcome; Warm Ischemia
PubMed: 25432829
DOI: 10.1016/j.urology.2014.08.040 -
Liver Transplantation : Official... Nov 2023
Topics: Humans; Warm Ischemia; Liver Transplantation; Perfusion; Kidney; Tissue Donors; Organ Preservation; Ischemia
PubMed: 37367963
DOI: 10.1097/LVT.0000000000000196 -
Analytical Biochemistry Apr 2012Surgically removed samples of high quality provide more accurate and reliable results in downstream molecular assays. Some factors, including the type of anesthesia,... (Review)
Review
Surgically removed samples of high quality provide more accurate and reliable results in downstream molecular assays. Some factors, including the type of anesthesia, surgical manipulation, transport time and mode, preservation method, storage length, and number of freeze-thaw cycles, can affect biosample quality and the subsequent gene expression analysis. Warm ischemia resulting from these factors has a substantial effect on biosample quality and is the focus of this mini review. We classified the effects of warm ischemia on gene expression as (i) warm ischemia-induced metabolic activity (WIMA) in living cells and (ii) warm ischemia-induced RNA degradation (WIRD). The differential effects of WIMA and WIRD on gene expression analysis appear to depend on the period after surgical removal. WIMA predominantly affects gene expression during the early stage after surgery, whereas WIRD has a more significant effect after tissue thawing. By a literature review, we also found that RNA isolated from surgically removed biopsies is stable, and high-quality RNA can be obtained for most nonfixed human tissue maintained at room temperature during the early period after surgery. Understanding these characteristics of gene expression variation should help biomedical researchers to avoid misleading gene expression results.
Topics: Biopsy; Freezing; Gene Expression Profiling; Gene Expression Regulation; Humans; RNA; RNA Stability; Warm Ischemia
PubMed: 22343191
DOI: 10.1016/j.ab.2012.02.003 -
Transplantation Proceedings Jun 2007"Warm ischemia" is a term used to describe ischemia of cells and tissues under normothermic conditions. In the transplant setting, this term is used to describe two...
UNLABELLED
"Warm ischemia" is a term used to describe ischemia of cells and tissues under normothermic conditions. In the transplant setting, this term is used to describe two physiologically distinct periods of ischaemia: (1) Ischemia during implantation, from removal of the organ from ice until reperfusion, and (2) Ischemia during organ retrieval, from the time of cross clamping (or of asystole in non-heart-beating donors), until cold perfusion is commenced. These periods of warm ischemia differ in their nature and the magnitude of their pathophysiologic consequences. In much transplant literature, however, the term "warm ischaemia" is used to describe both of these periods indiscriminately. This paper attempts to produce a definition to distinguish between the two periods of warm ischemia.
METHODS
We conducted a questionnaire survey of all UK transplant surgeons. The definitions proposed in the survey were: (a) warm ischemia and re-warm ischemia; (b) first warm ischemia and second warm ischemia; (c) in-situ warm ischemia and ex-vivo warm ischemia; (d) warm ischemia in donor and warm ischemia in recipient; (e) no opinion or other opinion.
RESULTS
There was a 64% response rate among 134 consultants with no consensus definition being reached. The majority of consultants (31.4%) preferred the terms "warm ischemia in donor", and "warm ischemia in recipient" to distinguish the two periods.
CONCLUSIONS
This paper highlights the need to adopt uniform terms to avoid confusion between different types of warm ischemia in transplantation.
Topics: Humans; Hypothermia; Organ Transplantation; Physicians; Surveys and Questionnaires; Tissue and Organ Harvesting; United Kingdom; Warm Ischemia
PubMed: 17580133
DOI: 10.1016/j.transproceed.2007.02.061 -
Surgery Apr 2022
Topics: Humans; Stents; Tissue Donors; Tissue and Organ Procurement; Warm Ischemia
PubMed: 35123796
DOI: 10.1016/j.surg.2021.12.038 -
Experimental and Clinical... Feb 2020Delayed graft function after kidney transplant can affect patient and graft survival, resulting in prolonged hospital stay and need for dialysis. Ischemia times during...
OBJECTIVES
Delayed graft function after kidney transplant can affect patient and graft survival, resulting in prolonged hospital stay and need for dialysis. Ischemia times during organ procurement and reanastomosis at transplant are key factors in delayed graft function.
MATERIALS AND METHODS
We analyzed all living- and deceased-donor renal transplants in Ireland over a 33-month period, with effect of warm ischemia time during anastomosis on delayed graft function being the primary outcome. We performed statistical regression analyses to account for confounding variables. Patients had identical surgical technique and immunosuppression protocols.
RESULTS
Of 481 transplants during the study period, 20 patients were excluded because of paired-kidney exchange, nephron dosing transplant, or simul-taneous pancreas-kidney transplant. In the donor pool, 70% were donors after brainstem death, 3.6% were donors after cardiac death, and 26% were living donors. All living donors were direct altruistic donors and underwent stringent assessment via the ethics committee and multidisciplinary team meeting. Of living donors, 8% were not related. These were true altruistic donors who were acquaintances of the recipients and volunteered themselves for assessment. They were assessed in accordance with the declaration of Istanbul and received no compensation of any kind for donation. Of total patients, 18% had delayed graft function, defined as need for dialysis within 7 days of transplant. Warm ischemia time during anastomosis significantly affected risk of delayed graft function but not graft survival or function at 3 months. This factor did not correlate with hospital stay duration. Time on dialysis and recipient weight significantly correlated with risk of delayed graft function.
CONCLUSIONS
Our findings support a role for minimizing warm ischemia time during anastomosis to reduce delayed graft function and need for dialysis in the perioperative period. However, a longer time does not appear to affect creatinine levels and therefore graft function at 3 months.
Topics: Adult; Anastomosis, Surgical; Body Weight; Databases, Factual; Delayed Graft Function; Female; Humans; Ireland; Kidney Failure, Chronic; Kidney Transplantation; Living Donors; Male; Middle Aged; Renal Dialysis; Risk Assessment; Risk Factors; Time Factors; Treatment Outcome; Vascular Surgical Procedures; Warm Ischemia
PubMed: 31266437
DOI: 10.6002/ect.2018.0377 -
International Braz J Urol : Official... 2021To quantitatively evaluate the possible long-term protective effects of quercetin during renal warm ischemia.
PURPOSE
To quantitatively evaluate the possible long-term protective effects of quercetin during renal warm ischemia.
MATERIALS AND METHODS
Male rats were allocated into 4 groups: sham (S), sham quercetin (SQ), ischemia (I), and ischemia quercetin (IQ). Groups SQ and IQ received quercetin (50mg/kg) before and after surgery. Groups I and IQ had their left renal vessels clamped for 60 minutes. All animals were euthanized four weeks after the procedure, and serum urea and creatinine levels were measured. Renal weight and volume, cortex-non-cortex area ratio (C-NC), cortical volume (CV), glomerular volumetric density (Vv[glom]), volume-weighted glomerular volume (VWGV) and number of glomeruli per kidney (N[glom]) were evaluated by stereological methods. Results were considered statistically significant when p < 0.05.
RESULTS
Serum urea levels in group I increased by 10.4% in relation to group S, but no differences were observed among the other groups. The C-NC of group I was lower than those of all other groups, and group IQ had similar results to sham groups. The Vv[glom] and N[glom] of group I were lower than those of group S (33.7% and 28.3%, respectively) and group IQ had no significant difference compared to the S group.
CONCLUSIONS
Quercetin was effective as a nephroprotective agent in preventing the glomerular loss observed when the kidney was subjected to warm ischemia. This suggests that this flavonoid may be used preventively in kidney surgery, when warm ischemia is necessary, such as partial nephrectomy.
Topics: Animals; Kidney; Kidney Glomerulus; Male; Nephrectomy; Quercetin; Rats; Rodentia; Warm Ischemia
PubMed: 33848072
DOI: 10.1590/S1677-5538.IBJU.2020.0358