L. W. E. van Heurn

Reduction of circulating redox-active iron by apotransferrin protects against renal ischemia-reperfusion injury

Background. Warm ischemia-reperfusion (I/R) injury plays an important role in posttransplant organ failure. In particular, organs from marginal donors suffer I/R injury. Although iron has been implicated in the pathophysiology of renal I/R injury, the mechanism of iron-mediated injury remains to be established. The authors therefore investigated the role of circulating redox-active iron in an experimental model for renal I/R injury. Methods. Male Swiss mice were subjected to unilateral renal ischemia for 45 min, followed by contralateral nephrectomy and reperfusion. To investigate the role of circulating iron, mice were treated with apotransferrin, an endogenous iron-binding protein, or iron-saturated apotransferrin (holotransferrin). Results. Renal ischemia induced a significant increase in circulating redox-active iron levels during reperfusion. Apotransferrin, in contrast to holotransferrin, reduced the amount of circulating redox-active iron and abrogated renal superoxide formation. Apotransferrin treatment did not affect I/R-induced renal apoptosis, whereas holotransferrin aggravated apoptotic cell death. Apotransferrin, in contrast to holotransferrin, inhibited the influx of neutrophils. Both apo- and holotransferrin reduced I/R-induced complement deposition, indicating that the effects of transferrin are differentially mediated by its iron and protein moiety. Finally, apotransferrin, in contrast to holotransferrin, dose-dependently inhibited the loss of renal function induced by ischemia. Conclusions. Redox-active iron is released into the circulation in the course of renal I/R. Reducing the amount of circulating redox-active iron by treatment with apotransferrin protects against renal I/R injury, inhibiting oxidative stress, inflammation, and loss of function. Apotransferrin could be used in the treatment of acute renal failure, as seen after transplantation of ischemically damaged organs.

Urine based detection of intestinal mucosal cell damage in neonates with suspected necrotising enterocolitis

Necrotising enterocolitis (NEC) is a severe gastrointestinal disease with a mortality of 20–40%, affecting predominantly premature neonates.1 In the early phase of the disease NEC continues to present a diagnostic challenge for the attending clinician. The signs and symptoms are often non-specific, including gastrointestinal problems such as abdominal distension and feeding intolerance, which are also among the most prevalent presenting features of neonatal sepsis.2 The diagnosis is further hampered by the limited diagnostic accuracy of the laboratory and radiological tests currently in use.3,4nnHistopathologically, NEC is characterised by intestinal coagulative or ischaemic necrosis, starting at the mucosa and extending into the submucosa and muscularis externa.1 We sought a non-invasive test to find evidence of enterocyte cell death in infants with gastrointestinal symptoms suspicious of NEC, in order to differentiate NEC from other neonatal diseases that present with abdominal signs.nnIntestinal fatty acid binding protein (I-FABP) has been reported to be a useful plasma marker for early enterocyte cell death.5,6 The small (14–15 kDa) cytosolic I-FABP is specifically present in mature enterocytes of small and large intestine and is released as soon as cell membrane integrity is compromised. I-FABP is present in very small amounts in the plasma of healthy individuals, probably representing the normal turnover of enterocytes, but levels …

Kidney Transplantation from Donors after Cardiac Death: Uncontrolled versus Controlled Donation

Kidney donation after cardiac death has been popularized over the last decade. The majority of these kidneys are from controlled donors. The number of organs for transplantation can be further increased by uncontrolled donors after cardiac death. The outcome of uncontrolled compared to controlled donor kidney transplantation is relatively unknown. We compared the long‐term outcome of kidney transplantation from uncontrolled (n = 128) and controlled (n = 208) donor kidneys procured in the Maastricht region from January 1, 1981 until January 1, 2008, and transplanted in the Eurotransplant region. The incidence of primary nonfunction and delayed graft function in both uncontrolled and controlled donor kidneys is relatively high (22% vs. 21%, and 61% vs. 56%, p = 0.43, respectively). Ten‐year graft and recipient survival are similar in both groups (50% vs. 46%, p = 0.74 and 61% vs. 60%, p = 0.76, respectively). Estimated glomerular filtration rates 1 year after transplantation are 40 ± 16 versus 42 ± 19 mL/min/1.73 m2, p = 0.55, with a yearly decline thereafter of 0.67 ± 3 versus 0.70 ± 7 mL/min/1.73 m2/year, p = 0.97. The outcome of kidney transplantation from uncontrolled and controlled donors after cardiac death is equivalent. This justifies the expansion of the donor pool with uncontrolled donors to reduce the still growing waiting list for renal transplantation, and may stimulate the implementation of uncontrolled kidney donation programs.

Histological assessment of preimplantation biopsies may improve selection of kidneys from old donors after cardiac death

Kidneys from old donors after cardiac death (DCD) may increase the donor pool but the prognosis of these kidneys is unsatisfactory. To improve these results, we retrospectively evaluated the diagnostic utility of published selection algorithms for old donor kidneys. We studied all DCD kidney transplantations between January 1, 1994 and July 1, 2005 at our institution (n = 199). Selection algorithms were evaluated in the subset of kidney transplantations from donors aged 60 years or older (n = 52). For histological assessment of kidney biopsies, glomerulosclerosis, tubular atrophy, interstitial fibrosis and vascular narrowing were blindly scored. Functional kidney weight was calculated as renal mass multiplied by the fraction of nonsclerosed glomeruli. Graft function and survival of kidneys from DCD aged 60 years or older were inferior to those from younger DCD. Histological scores were associated with kidney function and graft survival of old DCD kidney transplantations. Functional kidney weight was associated with kidney function but not graft survival, while donor glomerular filtration rate (GFR), donor age and machine perfusion characteristics were associated with neither of the clinical outcomes of interest. We conclude that histological assessment of preimplantation biopsies may improve the selection of kidneys from old DCD and may therefore contribute to expansion of the donor pool.

Recipient hemodynamics during non-heart-beating donor kidney transplantation are major predictors of primary nonfunction.

Non‐heart‐beating donor (NHBD) kidneys may substantially expand the donor pool, but many transplant centers are reluctant to use these kidneys because of the relatively high incidence of primary nonfunction (PNF). In heart‐beating donor kidneys, intravascular fluid depletion during transplant surgery is associated with delayed graft function (DGF). Therefore, we studied the effect of the recipients hemodynamic status on the outcome of 177 NHBD kidney transplantations. Independent statistically significant predictors of PNF were average central venous pressure (CVP) below 6 cmH2O (adjusted odds ratio (AOR) 3.1 (95% CI: 1.4–7.1), p = 0.007), average systolic blood pressure below 110 mmHg (AOR 2.6 (95% CI: 1.1–5.9), p = 0.03) and pre‐operative diastolic blood pressure below 80 mmHg (AOR 2.4 (95% CI: 1.0–5.9), p = 0.05). Donor characteristics were not independently associated with PNF (p > 0.10). In a subgroup analysis of 56 paired kidneys, 29% of the recipients with the lower CVP of the pair experienced PNF compared with 11% of their counterparts with higher CVP (p = 0.09). Our study indicates that recipient hemodynamics during transplant surgery are major predictors of PNF. Therefore, improving recipient hemodynamics by expansion of the intravascular volume is expected to enhance the results of NHBD kidney transplantations and may enlarge the donor pool by increasing the acceptance of NHBD kidneys.

Factors associated with recurrence and metastasis in Sacrococcygeal Teratoma.

Sacrococcygeal teratoma (SCT) is a relatively uncommon tumour, with a high risk of recurrence and metastasis. The factors associated with recurrence and metastatic disease were studied.

Kidney Transplantation Using Elderly Non‐Heart‐Beating Donors: A Single‐Center Experience

Although acceptable outcomes have been reported in both non‐heart‐beating (NHB) and elderly donors individually, the large pool of elderly NHB donors has not yet been fully utilized. In 1994, we expanded our transplant protocol to include NHB donors aged over 65 years and this study compares the clinical outcomes with regular NHB transplantations. Up to June 2005, 24 patients were transplanted at our center with kidneys from NHB donors aged 65 years or more, whereas 176 patients received grafts from conventional NHB donors during the same period. Grafts from older donors were associated with inferior glomerular filtration rates (29 vs. 44 mL/min after 1 year, p = 0.01) and graft survival (52% vs. 68% after 5 years, p = 0.19) compared to younger NHB donor grafts, although the difference in graft survival was not statistically significant. Exclusion of older NHB donor kidneys with severe vascular pathology resulted in similar graft survival of older and younger NHB donor kidneys. We conclude that the use of elderly NHB donors in order to expand the donor pool was associated with unacceptable clinical outcomes and cannot be justified without further refinement in their selection, for example, by histological assessment of pretransplant biopsies.

Renovascular resistance of machine-perfused DCD kidneys is associated with primary nonfunction.

Donation after cardiac death (DCD) has shown to be a valuable extension of the donor pool despite a higher percentage of primary nonfunction (PNF). Limiting the incidence of PNF is of vital importance. Renovascular resistance is believed to predict graft outcome; however the literature is inconsistent. Therefore, we studied whether renovascular resistance is associated with PNF and whether this parameter should be used to discard donor kidneys. All transplanted DCD kidneys preserved by machine perfusion at our center between 1993 and 2007 were analyzed (n = 440). The effects of renovascular resistance on PNF, delayed graft function (DGF), and graft and patient survival were examined using multivariable analyses; predictive quality by calculating the area under the curve (AUC). We showed that renovascular resistance at the start of machine perfusion was significantly and independently associated with PNF (OR 2.040, 95% CI 1.362–3.056; p = 0.001), and DGF (OR 2.345, 95% CI 1.110–4.955; p = 0.025). Predictive quality was moderate (0.609, 95% CI 0.538–0.681). Graft and patient survival were not associated with renovascular resistance. We conclude that renovascular resistance in DCD kidneys is an independent risk factor for PNF; however, the predictive value is relatively low.

Tubular epithelial injury and inflammation after ischemia and reperfusion in human kidney transplantation.

Objective:To provide an integrated insight into the kinetics of tubular injury, inflammation, and oxidative stress after human kidney transplantation. Background:Tissue injury due to ischemia and reperfusion is an inevitable consequence of kidney transplantation. Tubular epithelial injury, inflammation, and oxidative stress play major roles in the pathophysiology of acute kidney injury in small animals, but it remains to be established whether this paradigm holds true for human kidney transplantation. Methods:Markers of tubular injury, inflammation, and oxidative stress were compared between recipients of kidneys from donors after cardiac death (DCD; N = 8) with prolonged ischemia and recipients of living donor kidneys with minimal ischemia (N = 8). Results:In the early postoperative period, creatinine clearance and tubular sodium reabsorption were profoundly reduced in DCD kidneys, coinciding with significantly increased urinary concentrations of tubular injury markers (neutrophil gelatinase-associated lipocalin, N-acetyl-&bgr;--glucosaminidase, and cystatin C) and an 18-fold increase in renal production of cytokeratin-18, indicating extensive necrotic cell death. Tubular injury in DCD kidneys was followed by greater systemic inflammatory activity and oxidative stress in the postoperative period (measured with 17-plex cytokine arrays and as plasma F2-isoprostanes, respectively). In contrast, no evidence of oxidative damage to either of the 2 kidney types was found in the early reperfusion period. Conclusions:These findings establish the relevance of observations in animal models for human kidney transplantation and form the basis for development of novel therapies to improve early graft function and expand the use of donor kidneys with prolonged ischemia.

Frequent but late donor-directed antibody formation after kidney transplantectomy within one month after grafting

Background. Donor-directed antibodies (DDA) can be formed in recipients after transplantation. There is not much known about their appearance in relation to the time after transplantation, nor the duration between transplantation and failure. Methods. DDA formation was retrospectively analyzed in patients transplanted between 1992 and 2004. Thirty-two nonimmunized first transplant recipients with transplantectomy within 4 weeks (median 6 days) were analyzed. Posttransplant sera were screened for HLA class I and II by flow cytometry (FC), ELISA, and cytotoxicity. All patients except one were treated with CNI (calcineurin inhibitor)-based immunosuppression. Results. Analysis was performed on the basis of FC results. In total, 16 of 32 patients became positive for DDA class I and/or II (50%). All antibodies were detected after transplantectomy. Class I and II antibodies were produced in 15 and 10 recipients, respectively. Multivariate regression analysis showed DDA positivity to be predicted by donor age (P=0.05). DDA were shown in patients who lost their graft due to immunological reasons but in a comparable percentage also in patients with nonimmunological graft loss. Conclusions. DDA after early transplantectomy appeared frequently but later than expected. In view of the growing number of marginal donors and the possible necessity of retransplantation, it is considered important to prolong the time of serum sampling and screening to at least 4 months. Immunization might escape attention when serum creening is restarted only from the time the patient is again referred to the waiting list.