Use of Mannitol for Ischemia Reperfusion Injury in Kidney Transplant and Partial Nephrectomies—Review of Literature

Calcineurin Inhibitor in NEuRoloGically deceased donors to decrease kidney delayed graft function study: study protocol of the CINERGY Pilot randomised controlled trial

INTRODUCTION

Most solid organ transplants originate from donors meeting criteria for death by neurological criteria (DNC). Within the organ donor, physiological responses to brain death increase the risk of ischaemia reperfusion injury and delayed graft function. Donor preconditioning with calcineurin inhibition may reduce this risk.

METHODS AND ANALYSIS

We designed a multicentre placebo-controlled pilot randomised trial involving nine organ donation hospitals and all 28 transplant programmes in the Canadian provinces of Ontario and Québec. We planned to enrol 90 DNC donors and their approximately 324 organ recipients, totalling 414 participants. Donors receive an intravenous infusion of either tacrolimus 0.02 mg/kg over 4 hours prior to organ retrieval, or a matching placebo, while monitored in an intensive care unit for any haemodynamic changes during the infusion. Among all study organ recipients, we record measures of graft function for the first 7 days in hospital and we will record graft survival after 1 year. We examine the feasibility of this trial with respect to the proportion of all eligible donors enrolled and the proportion of all eligible transplant recipients consenting to receive a CINERGY organ transplant and to allow the use of their health data for study purposes. We will report these feasibility outcomes as proportions with 95% CIs. We also record any barriers encountered in the launch and in the implementation of this trial with detailed source documentation.

ETHICS AND DISSEMINATION

We will disseminate trial results through publications and presentations at participating sites and conferences. This study has been approved by Health Canada (HC6-24-c241083) and by the Research Ethics Boards of all participating sites and in Québec (MP-31-2020-3348) and Clinical Trials Ontario (Project #3309).

TRIAL REGISTRATION NUMBER

NCT05148715.

Considerations regarding anesthesia for renal transplantation

Renal transplantation is a complex surgical procedure requiring meticulous anesthetic planning to ensure patient safety and optimal graft function. In this comprehensive review, we examined various aspects of anesthesia management during renal transplantation, including preoperative, intraoperative, and postoperative care. Preoperative optimization involves the identification and management of risks to mitigate perioperative complications. Treatment with erythropoiesis-stimulating agents is recommended to correct anemia in transplant recipients with hemoglobin levels below 9-10 g/dl. Intraoperative management focuses on hemodynamic monitoring, maintenance of intravascular volume, and careful selection of anesthetic techniques. Neuromuscular monitoring and the appropriate use of neuromuscular blocking and reversal agents are considered essential. Further, hemodynamic goals include maintaining the mean arterial pressure within the range of 80-110 mmHg. In addition, attention should be paid to perioperative glycemic control, temperature management, and diuretic use. In postoperative management, multimodal analgesia and the prevention of postoperative delirium contribute to optimal recovery. The implementation of enhanced recovery after surgery principles can further improve outcomes. Collaborative efforts among surgical teams, anesthesiologists, and healthcare professionals are crucial for achieving successful renal transplantation outcomes.

Calcineurin Inhibition in Deceased Organ Donors: A Systematic Review and Meta-analysis of Preclinical Studies

Background

Preconditioning deceased organ donors with calcineurin inhibitors (CNIs) may reduce ischemia-reperfusion injury to improve transplant outcomes.

Methods

We searched MEDLINE, EMBASE, Cochrane Library, and conference proceedings for animal models of organ donation and transplantation, comparing donor treatment with CNIs with either placebo or no intervention, and evaluating outcomes for organ transplantation. Reviewers independently screened and selected studies, abstracted data, and assessed the risk of bias and clinical relevance of included studies. Where possible, we pooled results using meta-analysis; otherwise, we summarized findings descriptively.

Results

Eighteen studies used various animals and a range of CNI agents and doses and evaluated their effects on a variety of transplant outcomes. The risk of bias and clinical applicability were poorly reported. Pooled analyses suggested benefit of CNI treatment on early graft function in renal transplants (3 studies; serum creatinine: ratio of means [RoM] 0.54; 95% confidence interval [CI], 0.34-0.86) but not for liver transplants (2 studies; serum alanine transaminase: RoM 0.61; 95% CI, 0.30-1.26; and serum aspartate aminotransferase: RoM 0.58; 95% CI, 0.26-1.31). We found no reduction in graft loss at 7 d (2 studies; risk ratio 0.54; 95% CI, 0.08-3.42). CNI treatment was associated with reduced transplant recipient levels of interleukin-6 (4 studies; RoM 0.36; 95% CI, 0.19-0.70), tumor necrosis factor-alpha (5 studies; RoM 0.36; 95% CI, 0.12-1.03), and cellular apoptosis (4 studies; RoM 0.30; 95% CI, 0.19-0.47).

Conclusions

Although this compendium of animal experiments suggests that donor preconditioning with CNIs may improve early kidney graft function, the limited ability to reproduce a true clinical environment in animal experiments and to assess for risk of bias in these experiments is a serious weakness that precludes current clinical application.

Anaesthetic Approach to Enhanced Recovery after Surgery for Kidney Transplantation: A Narrative Review

Enhanced recovery after surgery (ERAS) protocols are designed to reduce medical complications, the length of hospital stays (LoS), and healthcare costs. ERAS is considered safe and effective for kidney transplant (KTx) surgery. KTx recipients are often frail with multiple comorbidities. As these patients follow an extensive diagnostic pathway preoperatively, the ERAS protocol can ideally be implemented at this stage. Small singular changes in a long perioperative pathway can result in significant positive outcomes. We have investigated the current evidence for an ERAS pathway related to anaesthetic considerations in renal transplant surgery for adult recipients.

Mannitol Use is Renal Protective in Patients with Chronic Kidney Disease Requiring Suprarenal Aortic Clamping

OBJECTIVES

Objective: Mannitol is often administered during open juxtarenal or suprarenal aortic surgery to prevent ischemic injury to the kidneys. Prior evidence evaluating the benefits of intraoperative mannitol in reducing ischemia/reperfusion injury is conflicting and largely based on small, retrospective series. The aim of this study was to evaluate the effect of mannitol in preventing postoperative hemodialysis in patients undergoing open abdominal aortic aneurysm (AAA) repair where proximal control involved temporary renal ischemia.

METHODS

Methods: The Society for Vascular Surgery Quality Initiative database was queried for all patients undergoing elective open AAA repair between 2003 and 2020. Patients were included in the current analysis if the proximal aortic clamp was placed above at least one renal artery. Chronic kidney disease (CKD) was defined as Cr >1.8mg/dL. Primary endpoints were 30-day major morbidity (myocardial infarction, respiratory complications, lower extremity or intestinal ischemia, and the need for temporary or permanent hemodialysis) and mortality. Comparisons were made between the mannitol and non-mannitol cohorts and stratified by the presence of pre-existing CKD.

RESULTS

Results: During the study period, 4,156 patients underwent elective open AAA repair requiring clamp placement above one (32.7%) or both (67.3%) renal arteries; 182 patients (4.4%) had pre-existing CKD. Overall, 69.8% of patients received mannitol during their surgery. Mannitol was more frequently used in cases involving clamp placement above both renal arteries (70.3%) than one renal artery (61.5%). While prolonged ischemia time (greater than 40 minutes) was associated with higher risk of post-operative dialysis in patients without CKD, it was not significant in patients with baseline CKD. On univariate analysis, mannitol use in patients with CKD was associated with lower risk of post-operative dialysis (p=0.005). This remained significant on multivariate analysis (p=0.008). Mannitol use did not appear to confer renal protective effects in patients without baseline CKD.

CONCLUSIONS

Conclusion: Mannitol use was associated with a decreased risk of need for post-operative hemodialysis in patients with CKD undergoing suprarenal aortic clamping for open aneurysm repair. In appropriately selected patients, particularly those with underlying renal insufficiency, mannitol may confer a renal protective effect in open repair of pararenal AAA requiring suprarenal clamping.

Mannitol Production by Heterofermentative Lactic Acid Bacteria: a Review

Obesity, diabetes, and other cardiovascular diseases are directly related to the high consumption of processed sugars with high caloric content. The current food industry has novel trends related to replacing highly caloric sugars with non-caloric or low-calorie sweeteners. Mannitol, a polyol, represents a suitable substitute because it has a low caloric content and does not induce a glycemic response, which is crucial for diabetic people. Consequently, this polyol has multiple applications in the food, pharmaceutical, and medicine industries. Mannitol can be produced by plant extraction, chemical or enzymatic synthesis, or microbial fermentation. Different in vitro processes have been developed regarding enzymatic synthesis to obtain mannitol from fructose, glucose, or starch-derived substrates. Various microorganisms such as yeast, fungi, and bacteria are applied for microbial fermentation. Among them, heterofermentative lactic acid bacteria (LAB) represent a reliable and feasible alternative due to their metabolic characteristics. In this regard, the yield and productivity of mannitol depend on the culture system, the growing conditions, and the culture medium composition. In situ mannitol production represents a novel approach to decrease the sugar content in food and beverages. Also, genetic engineering offers an interesting option to obtain mannitol-producing strains. This review presents and discusses the most significant advances that have been made in the mannitol production through fermentation by heterofermentative LAB, including the pertinent and critical analysis of culture conditions considering broth composition, reaction systems, and their effects on productivities and yields.

Effect of Mannitol on Kidney Function After Kidney Transplantation: A Systematic Review and Meta-Analysis

BACKGROUND

The effect of mannitol usage during kidney donation and kidney transplantation is still unclear. Therefore, we performed a systematic review and meta-analysis to research the difference in graft function between kidney grafts treated with and without mannitol.

METHODS

A literature search was performed in 5 databases and included 8 eligible studies out of 3570 references, which were included up to July 12, 2021. Relevant outcomes for analysis were graft survival, rejection, acute renal failure, delayed graft function, renal failure, creatinine clearance, diuresis, and serum creatinine.

RESULTS

Eight studies were identified, 1 study examining the effect of mannitol during kidney donation and 7 studies during kidney transplantation, of which 6 eligible for meta-analysis. A total of 1143 patients were included in these studies. The following outcome measures demonstrated significant differences in favor of mannitol usage compared with a control group: acute renal failure (risk ratio [RR], 0.45; 95% confidence interval [CI], 0.26-0.79; P < .01]) and delayed graft function (RR, 0.25; 95% CI, 0.08-0.77; P = 0.02 and RR, 0.69; 95% CI, 0.51-0.94; P = 0.94). Differences in other outcome parameters were not significant.

CONCLUSIONS

This systematic review and meta-analysis suggested that the use of mannitol during kidney transplantation leads to lower incidence of acute renal failure and delayed graft function. For all other outcomes, no significant difference was found. Further research should be conducted on the use of mannitol during donor nephrectomy because of the limited availability of studies. Finally, for interpretation of the outcomes, the quality of the evidence should be taken into consideration and we emphasize the need for more up-to-date research.

The use of mannitol in partial nephrectomy for renal function preservation: meta-analysis and systematic review of comparative studies

Objective:

We aimed to assess the effect and safety of mannitol use in partial nephrectomy for renal function preservation.

Methods:

A systematic literature search was performed. Randomised controlled trials and non-randomised controlled trials comparing with versus without mannitol use in partial nephrectomy were screened and evaluated according to Cochrane Collaboration recommendations. Outcomes assessed were percentage change from preoperative estimated glomerular filtration rate, estimated blood loss and complications. The standardised mean difference (SMD) and risk ratio (RR) with corresponding 95% confidence intervals were extrapolated. Effect estimates were pooled using the inverse variance method with a random-effects model. Subgroup analysis was performed according to study design and follow-up duration. Grading of recommendations, assessment, development and evaluations assessment was used to rate the quality of evidence.

Results:

A total of 1136 patients from two randomised controlled trials ( n=264) and six non-randomised controlled trials ( n=872) were included. The included randomised controlled trials had some concerns regarding a high risk of bias; while the non-randomised controlled trials were all retrospective studies with moderate to serious concern for risk of bias. Overall pooled effect estimates for short and long-term follow-up showed no significant differences between intervention groups for percentage change from preoperative estimated glomerular filtration rate (SMD 0.09, 95% confidence interval (CI) −0.11, 0.29; SMD −0.06, 95% CI −0.22, 0.06, respectively). Likewise, no between-group difference was noted for intraoperative blood loss and complication rates (SMD 0.05, 95% CI −0.08, 0.17; RR 1.07, 95% CI 0.6, 1.82, respectively).

Conclusion:

The pooled effect estimates from both randomised and non-randomised comparative studies illustrated no overall short-term or long-term advantage with mannitol use in partial nephrectomy for the preservation of estimated glomerular filtration rate. Likewise, no difference was noted for intraoperative blood loss or complication rates. However, to date there is only a very low to low quality of evidence available to extrapolate conclusions.

Level of evidence:

Very low to low

Mannitol and renal graft injury in patients undergoing deceased donor renal transplantation - a randomized controlled clinical trial

Background

Ischaemia/reperfusion (I/R) injury is associated with renal tissue damage during deceased donor renal transplantation. The effect of mannitol to reduce I/R injury during graft reperfusion in renal transplant recipients is based on weak evidence. We evaluated the effect of mannitol to reduce renal graft injury represented by 16 serum biomarkers, which are indicators for different important pathophysiological pathways. Our primary outcome were differences in biomarker concentrations between the mannitol and the placebo group 24 h after graft reperfusion. Additionally, we performed a linear mixed linear model to account biomarker concentrations before renal transplantation.

Methods

Thirty-four patients undergoing deceased donor renal transplantation were randomly assigned to receive either 20% mannitol or 0.9% NaCl placebo solution before, during, and after graft reperfusion. Sixteen serum biomarkers (MMP1, CHI3L1, CCL2, MMP8, HGF, GH, FGF23, Tie2, VCAM1, TNFR1, IGFBP7, IL18, NGAL, Endostatin, CystC, KIM1) were measured preoperatively and 24 h after graft reperfusion using Luminex assays and ELISA.

Results

Sixteen patients in each group were analysed. Tie2 differed 24 h after graft reperfusion between both groups (p = 0.011). Change of log2 transformed concentration levels over time differed significantly in four biomarkers (VCAM1,Endostatin, KIM1, GH; p = 0.007; p = 0.013; p = 0.004; p = 0.033; respectively) out of 16 between both groups.

Conclusion

This study showed no effect of mannitol on I/R injury in patients undergoing deceased renal transplantation. Thus, we do not support the routinely use of mannitol to attenuate I/R injury.

Trial registration

NCT02705573. Registered on 10th March 2016.

Harnessing Adaptive Evolution to Achieve Superior Mannitol Production by Lactococcus lactis Using Its Native Metabolism

Mannitol can be obtained as a by-product of certain heterolactic lactic acid bacteria, when grown on substrates containing fructose. Lactococcus lactis, a homolactic lactic acid bacterium, normally does not form mannitol but can be persuaded into doing so by expressing certain foreign enzyme activities. In this study, we find that L. lactis has an inherent capacity to form mannitol from glucose. By adaptively evolving L. lactis or derivatives blocked in NAD⁺ regenerating pathways, we manage to accelerate growth on mannitol. When cells of the adapted strains are resuspended in buffer containing glucose, 4-58% of the glucose metabolized is converted into mannitol, in contrast to nonadapted strains. The highest conversion was obtained for a strain lacking all major NAD⁺ regenerating pathways. Mannitol had an inhibitory effect on the conversion, which we speculated was due to the mannitol uptake system. After its inactivation, 60% of the glucose was converted into mannitol by cells suspended in glucose buffer. Using a two-stage setup, where biomass first was accumulated by aerated culturing, followed by a nonaerated phase (static conditions), it was possible to obtain 6.1 g/L mannitol, where 60% of the glucose had been converted into mannitol, which is the highest yield reported for L. lactis.

Advances on Cell Autophagy and Its Potential Regulatory Factors in Renal Ischemia-Reperfusion Injury

Ischemia-reperfusion injury is a major reason for acute kidney injury and various kidney diseases. Autophagy plays an important role during renal ischemia-reperfusion injury (RIRI), but it remains controversial whether autophagy contributes to cell survival or ischemia-reperfusion-induced cell death. In the review, we summarized the function of autophagy in the progression of acute ischemic kidney injury, as well as its related molecular mechanisms. While analyzing the opposite roles of autophagy in RIRI, it was concluded that the protective or detrimental function of autophagy was depending on the timing and amount of the activation of cell autophagy. We also summarized the regulatory agents, including active compounds, proteins, or microRNAs (miRNAs), which regulated the cell autophagy during renal acute ischemic kidney injury process. This explained why the opposite conclusion occurred when cell autophagy was studied in the RIRI models from different researchers. Therefore, the article provided a hypothesis to control cell autophagy at the appropriate timing and intensity so as to alleviate renal injury and sustain cell survival of the renal cell.

Exposure to Hyperchloremia Is Associated with Poor Early Recovery of Kidney Graft Function after Living-Donor Kidney Transplantation: A Propensity Score-Matching Analysis

The effects of hyperchloremia on kidney grafts have not been investigated in patients undergoing living-donor kidney transplantation (LDKT). In this study, data from 200 adult patients undergoing elective LDKT between January 2016 and December 2017 were analyzed after propensity score (PS) matching. The patients were allocated to hyperchloremia and non-hyperchloremia groups according to the occurrence of hyperchloremia (i.e., ≥110 mEq/L) immediately after surgery. Poor early graft recovery was defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² during the first 48 hours after surgery. After PS matching, no significant differences in perioperative recipient or donor graft parameters were observed between groups. Although the total amount of crystalloid fluid infused during surgery did not differ between groups, the proportions of main crystalloid fluid type used (i.e., 0.9% normal saline vs. Plasma Solution-A) did. The eGFR increased gradually during postoperative day (POD) 2 in both groups. However, the proportion of patients with eGFR > 60 mL/min/1.73 m² on POD 2 was higher in the non-hyperchloremia group than in the hyperchloremia group. In this PS-adjusted analysis, hyperchloremia was significantly associated with poor graft recovery on POD 2. In conclusion, exposure to hyperchloremia may have a negative impact on early graft recovery in LDKT.