Search

Background: Normothermic machine perfusion (NMP) protocols using blood-based solutions are commonly used in the assessment of kidneys before transplantation. This procedure is, nevertheless, limited by blood availability and warrants the search for alternatives. We compared a blood-based solution with a serum-like preservation solution (Aqix) enriched with colloids with and without red blood cells (RBCs)., Methods: Porcine kidneys retrieved from an abattoir were subjected to 30 min of warm ischemia, followed by 3 h of hypothermic oxygenated machine perfusion at 4 °C. Subsequently, kidneys (n = 6 per group) were evaluated with NMP for 4 h with 5 different solutions: diluted blood, Aqix with BSA ± RBCs, or Aqix with dextran 40 ± RBCs., Results: Throughout NMP, markers of renal function and tubular metabolism were favorable in groups with RBCs. The addition of RBCs resulted in 4- to 6-fold higher oxygen consumption rates. Controls had significantly higher ATP levels post-NMP, exhibited decreased production of oxidative stress markers, and had the highest creatinine clearance. In conclusion, this study shows that the addition of RBCs during NMP reduced renal injury, improved function, and was associated with increased renal metabolism., Conclusions: Although the RBC-BSA-supplemented Aqix solution was also able to support metabolism and renal function, a blood-based perfusion solution remains superior., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc.)

Competing Interests: The authors declare no conflicts of interest.

Background: During organ retrieval, surgeons estimate the degree of arteriosclerosis and this plays an important role in decisions on organ acceptance. Our study aimed to elucidate the association between macroscopic renal artery arteriosclerosis, donor kidney discard, and transplant outcome., Methods: We selected all transplanted and discarded kidneys in the Netherlands between January 1, 2000, and December 31, 2015, from deceased donors aged 50 y and older, for which data on renal artery arteriosclerosis were available (n = 2610). The association between arteriosclerosis and kidney discard, the relation between arteriosclerosis and outcome, and the correlation between macroscopic and microscopic arteriosclerosis were explored., Results: Macroscopic arteriosclerosis was independently associated with kidney discard (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.02-1.80; P = 0.03). Arteriosclerosis (any degree) was not significantly associated with delayed graft function (OR, 1.16; 95% CI, 0.94-1.43; P = 0.16), estimated glomerular filtration rate 1-y posttransplant (B, 0.58; 95% CI, -2.07 to 3.22; P = 0.67), and long-term graft survival (hazard ratio, 1.07; 95% CI, 0.86-1.33; P = 0.55). There was a significant association between mild arteriosclerosis and primary nonfunction (OR, 2.14; 95% CI, 1.19-3.84; P = 0.01). We found no correlation between macroscopic and histological arteriosclerosis, nor between histological arteriosclerosis and transplant outcome., Conclusions: Macroscopic arteriosclerosis of the renal artery was independently associated with kidney discard and somewhat associated with primary nonfunction posttransplant. However, there was no effect of arteriosclerosis on delayed graft function, estimated glomerular filtration rate at 1 y, or long-term graft survival. Our results are valid only after inevitable exclusion of discarded kidneys that had on average more arteriosclerosis. Hence, conclusions should be interpreted in the light of this potential bias.

Background: Brain death (BD)-related lipid peroxidation, measured as serum malondialdehyde (MDA) levels, correlates with delayed graft function in renal transplant recipients. How BD affects lipid peroxidation is not known. The extent of BD-induced organ damage is influenced by the speed at which intracranial pressure increases. To determine possible underlying causes of lipid peroxidation, we investigated the renal redox balance by assessing oxidative and antioxidative processes in kidneys of brain-dead rats after fast and slow BD induction., Methods: Brain death was induced in 64 ventilated male Fisher rats by inflating a 4.0F Fogarty catheter in the epidural space. Fast and slow inductions were achieved by an inflation speed of 0.45 and 0.015 mL/min, respectively, until BD confirmation. Healthy non-brain-dead rats served as reference values. Brain-dead rats were monitored for 0.5, 1, 2, or 4 hours, after which organs and blood were collected., Results: Increased MDA levels became evident at 2 hours of slow BD induction at which increased superoxide levels, decreased glutathione peroxidase (GPx) activity, decreased glutathione levels, increased inducible nitric oxide synthase and heme-oxygenase 1 expression, and increased plasma creatinine levels were evident. At 4 hours after slow BD induction, superoxide, MDA, and plasma creatinine levels increased further, whereas GPx activity remained decreased. Increased MDA and plasma creatinine levels also became evident after 4 hours fast BD induction., Conclusion: Brain death leads to increased superoxide production, decreased GPx activity, decreased glutathione levels, increased inducible nitric oxide synthase and heme-oxygenase 1 expression, and increased MDA and plasma creatinine levels. These effects were more pronounced after slow BD induction. Modulation of these processes could lead to decreased incidence of delayed graft function.

Background: Chronic transplant dysfunction (CTD) is the leading cause of long-term loss of the renal allograft. So far, no single test is available to reliably predict the risk for CTD. Monitoring of tryptophan (trp) metabolism through indoleamine 2.3-dioxygenase (IDO) has been previously proposed to predict acute rejection of human kidney transplants. Here, we investigate the potential of IDO/trp degradation along the kynurenine (kyn) pathway to predict the long-term outcome of human kidney transplantation., Methods: During the 2-year follow-up blood, urine, and kidney biopsies were collected from 48 renal transplant patients. Concentrations of kyn and trp in serum and urine were measured at 2 weeks, 6 months, and 2 years after transplantation. Kynurenine to tryptophan ratio was calculated as an estimate of trp degradation. To evaluate the histological changes and IDO expression, respectively, periodic acid schiff staining and immunohistochemistry for IDO were performed on biopsies taken at 6 months and 2 years., Results: Two years after transplantation, kyn/trp was increased in urine and decreased in serum as compared to 2-week values. In 2-year biopsies, IDO expression was mainly found in infiltrating inflammatory cells and in the glomeruli. The urine level of trp 2 weeks after transplantation predicted the serum creatinine 6 months and the estimated creatinine clearance 2 years after transplantation. Additionally, serum level of kyn 6 months after transplantation predicted the serum creatinine 2 years after transplantation., Conclusions: Early serum and urine levels of trp and kyn may offer a novel route for early detection of patients at risk for developing CTD.

Background: Chronic transplant dysfunction is the most common cause of graft failure on the long term. Proteinuria is one of the cardinal clinical signs of chronic transplant dysfunction. Albumin-bound fatty acids (FA) have been hypothesized to be instrumental in the etiology of renal damage induced by proteinuria. We therefore questioned whether high circulating FA could be associated with an increased risk for future development of graft failure in renal transplant recipients (RTR). To this end, we prospectively investigated the association of fasting concentrations of circulating nonesterified FA (NEFA) with the development of graft failure in RTR., Methods: Baseline measurements were performed between 2001 and 2003 in outpatient RTR with a functioning graft of more than 1 year. Follow-up was recorded until May 19, 2009. Graft failure was defined as return to dialysis or retransplantation., Results: We included 461 RTR at a median (interquartile range [IQR]) of 6.1 (3.3-11.3) years after transplantation. Median (IQR) fasting concentrations of NEFA were 373 (270-521) μM/L. Median (IQR) follow-up for graft failure beyond baseline was 7.1 (6.1-7.5) years. Graft failure occurred in 23 (15%), 14 (9%), and 9 (6%) of RTR across increasing gender-specific tertiles of NEFA (P=0.04). In a gender-adjusted Cox-regression analysis, log-transformed NEFA level was inversely associated with the development of graft failure (hazard ratio, 0.61; 95% confidence interval, 0.47-0.81; P<0.001)., Conclusions: In this prospective cohort study in RTR, we found an inverse association between fasting NEFA concentrations and risk for development of graft failure. This association suggests a renoprotective rather than a tubulotoxic effect of NEFA. Further studies on the role of different types of NEFA in the progression of renal disease are warranted.

Background: Chronic transplant dysfunction is the leading cause of long-term renal allograft loss. One of the histologic hallmarks of chronic transplant dysfunction is transplant vasculopathy characterized by accumulation of smooth muscle cells (SMCs) in the arterial subendothelial space, leading to ischemic graft failure. Currently, no therapy is available for transplant vasculopathy, and knowledge of the origin (donor vs. recipient) of neointimal cells may contribute to develop adequate strategies., Methods: Origin of neointimal SMCs, endothelial, and tubular cells was determined in four nephrectomy samples from male recipients transplanted with a female kidney. Recipient-derived cells were detected using X- and Y-chromosome-specific fluorescent in situ hybridization combined with immunofluorescent staining. Specificity and sensitivity of fluorescent in situ hybridization were determined with corresponding controls., Results: No Y-chromosome-positive cells were detected in the female to female graft, whereas approximately 31% of nucleated cells in male to male grafts had a detectable Y-chromosome. In female to male grafts, a recipient-derived population of neointimal alpha-smooth muscle actin-positive SMCs were detected (6%, range 3%-11%). Percentages of recipient-derived arterial endothelial cells, glomerular endothelial cells, and tubular epithelial cells were 14% (range 4%-32%), 19% (range 7%-31%) and 3% (range 2%-5%), respectively., Conclusions: Both donor- and recipient-derived cells contribute to vascular remodeling in clinical renal transplantation. The presence of alpha-smooth muscle actin in donor- and recipient-derived cells supports a constructive role for these cells in neointimal formation. However, the predominance of donor-derived cells in the neointima points to these cells as the likely therapeutic target.

Background: Brain death donors are frequently used for transplantation. Previous studies showed that brain death (BD) negatively affects the immunological and inflammatory status of both liver and kidney. Because the intestine is increasingly used as a donor organ and no information on effects of BD on small intestine is available we performed this study., Methods: We studied the inflammatory and apoptotic changes in donor intestine after BD induction. Brain death was induced in rats by inflation of a balloon catheter. Three groups (n=6) were compared: 1-hr BD, 4-hr BD, and sham-operated controls., Results: An increased polymorphonuclear cell influx in ileum, as a measure of inflammation, was observed in 1- and 4-hr BD group compared with controls. Jejunum showed a significant increase at the 4-hr BD group compared with the control group. Intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, and interleukin-6 were upregulated after 1- and 4-hr BD. Caspase-3 positive cells were found in jejunum and ileum after 4-hr BD on the top of the villi. Serum interleukin-6 was severely elevated in the 1- and 4-hr brain dead rats., Conclusion: These data show the early occurrence of intestinal inflammation and apoptosis after BD induction. These events may ultimately have a negative influence on the outcome of intestinal transplantation.

Background: Chronic transplant dysfunction is characterized by renal function decline and proteinuria. Kidney injury molecule (KIM)-1, a transmembrane tubular protein with unknown function, is undetectable in normal kidneys, but markedly induced after injury. Urinary KIM-1 excretion has been quantified as biomarker of renal damage. We prospectively studied whether urinary KIM-1 predicts graft loss, independent of renal function and proteinuria., Methods: Renal transplant recipients (n=145) visiting our outpatient clinic between August 2001 and July 2003 collected 24-hour urine samples for assessment of baseline urinary KIM-1 excretion (microsphere-based Luminex technology), and were followed for graft loss., Results: Recipients participated at a median (interquartile range) of 6.0 (2.5-12.0) years posttransplant in baseline measurements. Follow-up beyond baseline was 4.0 (3.2-4.5) years. Urinary KIM-1 excretion was 0.72 (0.42-1.37) ng per 24 hours. Occurrence of graft loss increased over tertiles of KIM-1 excretion: 3 (6.3%), 11 (22.4%), and 17 cases (35.4%; P=0.001), respectively. High KIM-1 excretion was associated with proteinuria, low creatinine clearance, and high donor age (all P<0.01). In multivariate Cox regression analyses, prediction of graft loss by KIM-1 appeared independent of creatinine clearance, proteinuria, and donor age. Hazard ratios (95% CI) for the second and third tertile of KIM-1 excretion were 3.6 (0.9-13.5) and 5.1 (1.5-17.8) in the final model., Conclusions: Urinary excretion of KIM-1 is an independent predictor of long-term graft loss and therefore a promising new biomarker in early prediction of graft loss.

Background: T helper cells are important modulators of the allograft immune response. A small number of genes are already known to be differentially expressed in T helper 1 (Th1) and T helper 2 (Th2) cells, but it is likely that many other genes are functionally important. To study gene expression in Th1 and Th2 cells, we used serial analysis of gene expression. One of the differentially expressed genes was TIAF-1, which is a TGF-beta 1-induced antiapoptotic factor, known to inhibit the cytotoxic effects of tumor necrosis factor-alpha on mouse fibroblasts. We hypothesized that TIAF-1 plays a protective role against apoptosis during allograft rejection., Methods: We examined TIAF-1 mRNA and protein expression in kidney and liver allograft biopsy specimens from patients with chronic or acute rejection by reverse transcriptase-polymerase chain reaction and immunohistochemistry., Results: TIAF-1 mRNA and protein were not detectable in normal kidney and liver; however, the expression of TIAF-1 was up-regulated in most biopsy specimens with chronic and a few with acute allograft rejection. Immunohistochemistry for TIAF-1 revealed expression in the inflammatory infiltrate and in tubular epithelial cells., Conclusions: TIAF-1 mRNA and protein are predominantly up-regulated in kidney and liver allografts with chronic rejection. This does not seem to be related to the cyclosporine A therapy. Expression of TIAF-1 in the lymphocytes during chronic allograft rejection may be related to the predominance of a Th2 response in this condition. The expression in the transplanted tissue may protect these cells from apoptosis.

Background: Nitric oxide (NO) is produced by nitric oxide synthases (NOS), which are either constitutively expressed in the kidney or inducible, in resident and infiltrating cells during inflammation and allograft rejection. NO is rapidly degraded to the stable end products nitrite and nitrate, which can be measured in serum and urine, and may serve as noninvasive markers of kidney allograft rejection., Methods: Total nitrite and nitrate levels (NOx) were measured in serum and urine thrice weekly after an overnight fast in 18 consecutive patients following renal cadaveric transplantation. Inducible NOS (iNOS) and endothelial NOS (eNOS) expression was immunochemically determined in renal biopsy specimens with or without acute rejection (AR)., Results: Serum NOx levels increased days before AR and were significantly higher at the moment of AR (27+/-12.4 micromol/L) compared with recipients with an uncomplicated course (13+/-7.6 micromol/L), but not compared with recipients with cyclosporine (CsA) toxicity (20+/-13.0 micromol/L). Urinary NOx levels were significantly lower during AR (20+/-13.6 micromol/mmol creatinine) compared with an uncomplicated course (64+/-25.2 micromol/mmol creatinine) or CsA toxicity (53.8+/-28.3 micromol/mmol creatinine). Interstitial and glomerular iNOS expression was significantly increased in biopsy specimens showing AR. Unexpectedly, glomerular eNOS expression was significantly decreased in patients with AR., Conclusions: This study reports differences in NOx levels in serum and urine, which may help discriminate AR episodes from an uncomplicated course or CsA toxicity. As expected, renal iNOS expression is increased in acute allograft rejection. The decrease in glomerular eNOS expression suggests an intriguing link between acute and chronic rejection.