Rapamycin Does Not Act as a Dietary Restriction Mimetic in the Protection against Ischemia Reperfusion Injury

Introduction: Short-term fasting protects against renal ischemia reperfusion injury (IRI). mTOR signaling is downregulated and may be involved in its protective effect. Rapamycin is considered a possible mimetic as it inhibits the mTOR pathway. This study examines the effect of rapamycin on renal IRI. Material and Methods: Mice were divided into four groups: ad libitum (AL), fasted (F), AL treated with rapamycin (AL+R), and F treated with rapamycin (F+R). Rapamycin was administered intraperitoneally 24 h before bilateral renal IRI was induced. Survival was monitored for 7 days. Renal cell death, regeneration, and mTOR activity were determined 48 h after reperfusion. Oxidative stress resistance of human renal proximal tubular and human primary tubular epithelial cells after rapamycin treatment was determined. Results: All F and F+R mice survived the experiment. Although rapamycin substantially downregulated mTOR activity, survival in the AL+R group was similar to AL (10%). Renal regeneration was significantly reduced in AL+R but not in F+R. After IRI (48 h), pS6K/S6K ratio was lower in F, F+R, and AL+R groups compared to AL fed animals (p = 0.02). In vitro, rapamycin also significantly downregulated mTOR activity (p &lt; 0.001) but did not protect against oxidative stress. Conclusion: Rapamycin pretreatment does not protect against renal IRI. Thus, protection against renal IRI by fasting is not exclusively mediated through inhibition of mTOR activity but may involve preservation of regenerative mechanisms despite mTOR downregulation. Therefore, rapamycin cannot be used as a dietary mimetic to protect against renal IRI.</p

Risk of post-transplant cardiovascular events in kidney transplant recipients with preexisting aortoiliac stenosis

Prediction of the risk of cardiovascular events (CVE's) is important to optimize outcomes after kidney transplantation. Aortoiliac stenosis is frequently observed during pre‐transplant screening. We hypothesized that these patients are at higher risk of post‐transplant CVE's due to the joint underlying atherosclerotic disease. Therefore, we aimed to assess whether aortoiliac stenosis was associated with post‐transplant CVE's. This retrospective, single‐center cohort study included adult kidney transplant recipients, transplanted between 2000 and 2016, with contrast‐enhanced imaging available. Aortoiliac stenosis was classified according to the Trans‐Atlantic Inter‐Society Consensus (TASC) II classification and was defined as significant in case of ≥50% lumen narrowing. The primary outcome was CVE‐free survival. Eighty‐nine of 367 patients had significant aortoiliac stenosis and were found to have worse CVE‐free survival (median CVE‐free survival: stenosis 4.5 years (95% confidence interval (CI) 2.8–6.2), controls 8.9 years (95% CI 6.8–11.0); log‐rank test P < .001). TASC II C and D lesions were independent risk factors for a post‐transplant CVE with a hazard ratio of 2.15 (95% CI 1.05–4.38) and 6.56 (95% CI 2.74–15.70), respectively. Thus, kidney transplant recipients with TASC II C and D aortoiliac stenosis require extensive cardiovascular risk management pre‐, peri,‐ and post‐transplantation

Learning curves of minimally invasive donor nephrectomy in a high-volume center: A cohort study of 1895 consecutive living donors

Background Few studies have investigated the learning curves of minimally invasive donor nephrectomy (MIDN) using the cumulative sum (CUSUM) analysis. In addition, no study has compared the learning curves of the different surgical MIDN techniques in one cohort study using the CUSUM analysis. This study aims to evaluate and compare learning curves for several MIDN using the CUSUM analysis. Methods A retrospective review of consecutive donors, who underwent MIDN between 1997 and 2019, was conducted. Three laparoscopic-assisted techniques were applied in our institution and included for analysis: laparoscopic (LDN), hand-assisted retroperitoneoscopic (HARP), and robot-assisted laparoscopic (RADN) donor nephrectomy. The outcomes were compared based on surgeon volume to develop learning curves for the operative time per surgeon. Results Out of 1895 MIDN, 1365 (72.0%) were LDN, 427 (22.5%) were HARP, and 103 (5.4%) were RADN. The median operative time and median blood loss were 179 (IQR, 139–230) minutes and 100 (IQR, 40–200) mL, respectively. The incidence of major complication was 1.2% with no mortality, and the median hospital stay was three (IQR, 3–4) days. The CUSUM analysis resulted in learning curves, defined by decreased operative time, of 23 cases in LDN, 45 cases in HARP, and 26 cases in RADN. Conclusions Our study shows different learning curves in three MIDN techniques with equal post-operative complications. The LDN and RADN learning curves are shorter than that of the hand-assisted donor nephrectomy. Our observations can be helpful for informing the development of teaching requirements for fellows to be trained in MIDN

Learning curve of kidney transplantation in a high-volume center: A Cohort study of 1466 consecutive recipients

Background The purpose of this study was to evaluate surgical outcomes of kidney transplantation (KTX) based on surgeon volume and surgeon experience, and to develop the learning curve model for KTX using the cumulative sum (CUSUM) analysis. Methods A retrospective review of 1466 consecutive recipients who underwent KTX between 2010 and 2017 was conducted. In total, 51 surgeons, including certified transplant surgeons, transplant fellows and surgical residents were involved in these procedures using a standardized protocol. Outcomes were compared based on surgeon volume (low [1–30] versus high [31≥] volume) and surgeon's type (consultant surgeons, fellows or residents). Results Operative time (129 versus 135 min, P Conclusions Surgical training in KTX using a standardize protocol can be accomplished with a steep learning curve without compromising perioperative outcomes under the careful selection of surgeons and procedures

Impact of sarcopenia on clinical outcomes for patients with resected hepatocellular carcinoma:a retrospective comparison of Eastern and Western cohorts

BACKGROUND: Patient fitness is important for guiding treatment. Muscle mass, as a reflection thereof, can be objectively measured. However, the role of East-West differences remains unclear. Therefore, we compared the impact of muscle mass on clinical outcomes after liver resection for hepatocellular carcinoma (HCC) in a Dutch [the Netherlands (NL)] and Japanese [Japan (JP)] setting and evaluated the predictive performance of different cutoff values for sarcopenia. METHOD: In this multicenter retrospective cohort study, patients with HCC undergoing liver resection were included. The skeletal muscle mass index (SMI) was determined on computed tomography scans obtained within 3 months before surgery. The primary outcome measure was overall survival (OS). Secondary outcome measures were: 90-day mortality, severe complications, length of stay, and recurrence-free survival. The predictive performance of several sarcopenia cutoff values was studied using the concordance index (C-index) and area under the curve. Interaction terms were used to study the geographic effect modification of muscle mass. RESULTS: Demographics differed between NL and JP. Gender, age, and body mass index were associated with SMI. Significant effect modification between NL and JP was found for BMI. The predictive performance of sarcopenia for both short-term and long-term outcomes was higher in JP compared to NL (maximum C-index: 0.58 vs. 0.55, respectively). However, differences between cutoff values were small. For the association between sarcopenia and OS, a strong association was found in JP [hazard ratio (HR) 2.00, 95% CI [1.230-3.08], P =0.002], where this was not found in NL (0.76 [0.42-1.36], P =0.351). The interaction term confirmed that this difference was significant (HR 0.37, 95% CI [0.19-0.73], P =0.005). CONCLUSIONS: The impact of sarcopenia on survival differs between the East and West. Clinical trials and treatment guidelines using sarcopenia for risk stratification should be validated in race-dependent populations prior to clinical adoption.</p

High performance methylated DNA markers for detection of colon adenocarcinoma

BACKGROUND: Colon cancer (CC) is treatable if detected in its early stages. Improved CC detection assays that are highly sensitive, specific, and available at point of care are needed. In this study, we systematically selected and tested methylated markers that demonstrate high sensitivity and specificity for detection of CC in tissue and circulating cell-free DNA. METHODS: Hierarchical analysis of 22 candidate CpG loci was conducted using The Cancer Genome Atlas (TCGA) COAD 450K HumanMethylation database. Methylation of 13 loci was analyzed using quantitative multiplex methylation-specific PCR (QM-MSP) in a training set of fresh frozen colon tissues (N = 53). Hypermethylated markers were identified that were highest in cancer and lowest in normal colon tissue using the 75th percentile in Mann–Whitney analyses and the receiver operating characteristic (ROC) statistic. The cumulative methylation status of the marker panel was assayed in an independent test set of fresh frozen colon tissues (N = 52) using conditions defined and locked in the training set. A minimal marker panel of 6 genes was defined based on ROC area under the curve (AUC). Plasma samples (N = 20 colorectal cancers, stage IV and N = 20 normal) were tested by cMethDNA assay to evaluate marker performance in liquid biopsy. RESULTS: In the test set of samples, compared to normal tissue, a 6-gene panel showed 100% sensitivity and 90% specificity for detection of CC, and an AUC of 1.00 (95% CI 1.00, 1.00). In stage IV colorectal cancer plasma versus normal, an 8-gene panel showed 95% sensitivity, 100% specificity, and an AUC of 0.996 (95% CI 0.986, 1.00) while a 5-gene subset showed 100% sensitivity, 100% specificity, and an AUC of 1.00 (95% CI 1.00, 1.00), highly concordant with our observations in tissue. CONCLUSIONS: We identified high performance methylated DNA marker panels for detection of CC. This knowledge has set the stage for development and implementation of novel, automated, self-contained CC detection assays in tissue and blood which can expeditiously and accurately detect colon cancer in both developed and underdeveloped regions of the world, enabling optimal use of limited resources in low- and middle-income countries. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13148-021-01206-2

Impact of Extraction Time during Donation after Circulatory Death Organ Procurement on Kidney Function after Transplantation in the Netherlands

Background:In The Netherlands, 60% of deceased-donor kidney offers are after donation after circulatory death. Cold and warm ischemia times are known risk factors for delayed graft function (DGF) and inferior allograft survival. Extraction time is a relatively new ischemia time. During procurement, cooling of the kidneys is suboptimal with ongoing ischemia. However, evidence is lacking on whether extraction time has an impact on DGF if all ischemic periods are included.Methods:Between 2012 and 2018, 1524 donation after circulatory death kidneys were procured and transplanted in The Netherlands. Donation and transplantation-related data were obtained from the database of the Dutch Transplant Foundation. The primary outcome parameter was the incidence of DGF. Results:In our cohort, extraction time ranged from 14 to 237 min, with a mean of 62 min (SD 32). In multivariate logistic regression analysis, extraction time was an independent risk factor for incidence of DGF (odds ratio per minute increase 1.008; 95% confidence interval, 1.003-1.013; P = 0.001). The agonal phase, hypoperfusion time, and anastomosis time were not independent risk factors for incidence of DGF. Conclusions:Considering all known ischemic periods during the donation after the circulatory death process, prolonged kidney extraction time increased the risk of DGF after kidney transplantation.</p

Learning curves of minimally invasive donor nephrectomy in a high-volume center: A cohort study of 1895 consecutive living donors

Background: Few studies have investigated the learning curves of minimally invasive donor nephrectomy (MIDN) using the cumulative sum (CUSUM) analysis. In addition, no study has compared the learning curves of the different surgical MIDN techniques in one cohort study using the CUSU