L.W. Ernest van Heurn

The Mannose-Binding Lectin-Pathway Is Involved in Complement Activation in the Course of Renal Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) is an important cause of acute renal failure (ARF). The complement system appears to be essentially involved in I/R injury. However, via which pathway the complement system is activated and in particular whether the mannose-binding lectin (MBL)-pathway is activated is unclear. This tempted us to study the activation and regulation of the MBL-pathway in the course of experimental renal I/R injury and in clinical post-transplant ARF. Mice subjected to renal I/R displayed evident renal MBL-depositions, depending on the duration of warm ischemia, in the early reperfusion phase. Renal deposition of C3, C6 and C9 was observed in the later reperfusion phase. The deposition of MBL-A and -C completely co-localized with the late complement factor C6, showing that MBL is involved in complement activation in the course of renal I/R injury. Moreover, the degree of early MBL-deposition correlated with complement activation, neutrophil-influx, and organ-failure observed in the later reperfusion phase. In serum of mice subjected to renal I/R MBL-A, levels increased in contrast to MBL-C levels, which dropped evidently. In line, liver mRNA levels for MBL-A increased, whereas MBL-C levels decreased. Renal MBL mRNA levels rapidly dropped in the course of renal I/R. Finally, in human biopsies, MBL-depositions were observed early after transplantation of ischemically injured kidneys. In line with our experimental data, in ischemically injured grafts displaying post-transplant organ-failure extensive MBL depositions were observed in peritubular capillaries and tubular epithelial cells. In conclusion, in experimental renal I/R injury and clinical post-transplant ARF the MBL-pathway is activated, followed by activation of the complement system. These data indicate that the MBL-pathway is involved in ischemia-induced complement activation.

Clinical Relevance of Pretransplant Donor-Directed Antibodies Detected by Single Antigen Beads in Highly Sensitized Renal Transplant Patients

Background. Highly sensitized (HS) patients (>85% panel-reactive antibodies) have a lower chance of receiving a donor kidney. Within Eurotransplant the Acceptable Mismatch (AM) program was developed to increase the chances of HS patients to receive a crossmatch-negative donor kidney. The standard crossmatch in the AM program is based on complement-dependent cytotoxicity. Methods. In this study we wanted to determine the clinical relevance of human leukocyte antigen donor-directed antibodies (DDA) detected by the single antigen (SA) bead technique, in the pretransplant sera of HS patients transplanted in our center through the Eurotransplant AM program. Results. From 34 AM patients, 27 were transplanted with 1 to 5 mismatches and 7 received a 0-mismatched graft. From the mismatched patients, retrospectively, 13 proved to possess pretransplant DDA by SA whereas 14 did not. No antibodies were found in the 0-mismatched group. Comparison of the DDA+ and DDA− patients in the human leukocyte antigen-mismatched donor/recipient combinations revealed a trend to an earlier and higher number of rejection episodes in DDA+ patients (P=0.08). No detrimental effect of DDA on graft survival was observed. Conclusions. This single-center study showed that in the AM program DDA detected by SA, and not by less-sensitive methods, may be related to acute rejection episodes but is not detrimental to long-term graft outcome. These findings question the increasing use of more-sensitive screening techniques for the allocation of organs.

Non-Invasive Markers for Early Diagnosis and Determination of the Severity of Necrotizing Enterocolitis

Objectives:To improve diagnosis of necrotizing enterocolitis (NEC) by noninvasive markers representing gut wall integrity loss (I-FABP and claudin-3) and gut wall inflammation (calprotectin). Furthermore, the usefulness of I-FABP to predict NEC severity and to screen for NEC was evaluated. Methods:Urinary I-FABP and claudin-3 concentrations and fecal calprotectin concentrations were measured in 35 consecutive neonates suspected of NEC at the moment of NEC suspicion. To investigate I-FABP as screening tool for NEC, daily urinary levels were determined in 6 neonates who developed NEC out of 226 neonates included before clinical suspicion of NEC. Results:Of 35 neonates suspected of NEC, 14 developed NEC. Median I-FABP, claudin-3, and calprotectin levels were significantly higher in neonates with NEC than in neonates with other diagnoses. Cutoff values for I-FABP (2.20 pg/nmol creatinine), claudin-3 (800.8 INT), and calprotectin (286.2 &mgr;g/g feces) showed clinically relevant positive likelihood ratios (LRs) of 9.30, 3.74, 12.29, and negative LRs of 0.08, 0.36, 0.15, respectively. At suspicion of NEC, median urinary I-FABP levels of neonates with intestinal necrosis necessitating surgery or causing death were significantly higher than urinary I-FABP levels in conservatively treated neonates.Of the 226 neonates included before clinical suspicion of NEC, 6 developed NEC. In 4 of these 6 neonates I-FABP levels were not above the cutoff level to diagnose NEC before clinical suspicion. Conclusions:Urinary I-FABP levels are not suitable as screening tool for NEC before clinical suspicion. However, urinary I-FABP and claudin-3 and fecal calprotectin are promising diagnostic markers for NEC. Furthermore, urinary I-FABP might also be used to predict disease severity.

Kidneys from Donors after Cardiac Death Provide Survival Benefit

The continuing shortage of kidneys for transplantation requires major efforts to expand the donor pool. Donation after cardiac death (DCD) increases the number of available kidneys, but it is unknown whether patients who receive a DCD kidney live longer than patients who remain on dialysis and wait for a conventional kidney from a brain-dead donor (DBD). This observational cohort study included all 2575 patients who were registered on the Dutch waiting list for a first kidney transplant between January 1, 1999, and December 31, 2004. From listing until the earliest of death, living-donor kidney transplantation, or December 31, 2005, 459 patients received a DCD transplant and 680 patients received a DBD transplant. Graft failure during the first 3 months after transplantation was twice as likely for DCD kidneys than DBD kidneys (12 versus 6.3%; P=0.001). Standard-criteria DCD transplantation associated with a 56% reduced risk for mortality (hazard ratio 0.44; 95% confidence interval 0.24 to 0.80) compared with continuing on dialysis and awaiting a standard-criteria DBD kidney. This reduction in mortality translates into 2.4-month additional expected lifetime during the first 4 years after transplantation for recipients of DCD kidneys compared with patients who await a DBD kidney. In summary, standard-criteria DCD kidney transplantation associates with increased survival of patients who have ESRD and are on the transplant waiting list.

Quality of life in patients with anorectal malformation or Hirschsprung's disease: Development of a disease-specific questionnaire

PURPOSE: Hirschsprungs disease and anorectal malformation are congenital diseases of the digestive tract with sequelae into adulthood. The quality of life of patients with these diseases is largely unknown. The aim of the study was 1) to construct a self-report disease-specific instrument to assess the quality of life in these patients and 2) to evaluate its psychometric performance. METHODS: An age-specific (6 and 7 years, 8–11 years, 12–16 years, and >17 years) questionnaire called the Hirschsprungs disease/anorectal malformation quality-of-life instrument was constructed. This questionnaire consists of 39 to 42 items, grouped into 10 to 11 scales that cover physical, emotional, and social functions as well as disease-related symptoms. Generic quality-of-life data were obtained in addition. A national sample of 715 patients aged six years and older completed the questionnaire (response rate, 61.9 percent). RESULTS: Multitrait scaling analyses confirmed the hypothesized scale structure with exception of the scales related to diet for the two youngest groups. Cronbachs alpha ranged (with exception of the diet scales) from 0.62 to 0.91 for children (8–11 years), from 0.69 to 0.82 for adolescents (12–16 years) and from 0.57 to 0.91 for adults. Selective scales were able to discriminate between subgroups of adult patients known to differ in disease and disease severity. Relevant scales of the adult version showed substantial correlations (>0.40) with comparable scales of the SF-36. In the two youngest age groups the differences between subgroups of patients were less significant, but in the expected direction. CONCLUSIONS: With the exception of the scales related to diet, the Hirschsprungs disease/anorectal malformation quality-of-life instrument is an instrument with promising reliability and validity, to measure the disease-specific quality of life of patients with anorectal malformation or Hirsch-sprungs disease.

Kidney transplantation from donors after cardiac death: a 25-year experience.

Background. The shortage of organ donors presents a major obstacle for adequate treatment of patients with end-stage renal disease. Donation after cardiac death (DCD) has been shown to increase the number of kidneys available for transplantation. The present article reports on the first 25 years of our experience with DCD kidney transplantation. Methods. This observational cohort study included all DCD kidney transplantations recovered in our procurement area from January 1, 1981 until December 31, 2005 (n=297). Patients were followed up until the earliest of death or December 31, 2006. Clinical outcomes were compared with matched kidney transplantations from brain dead donors (DBD, n=594), using multivariable regression models to adjust for potential confounders. Results. DCD activity resulted in a 44% increase in the number of deceased donor kidneys from our organ procurement area. After adjustment for potential confounders, the odds of primary nonfunction and delayed graft function were 7.5 (95% CI, 4.0–14.1; P<0.001) and 10.3 (95% CI, 6.7–15.9; P<0.001) times greater, respectively, for DCD kidneys compared with DBD kidneys. The high incidence of primary nonfunction of DCD kidneys resulted in an increased rate of graft loss (HR, 1.82; 95% CI, 1.37–2.42; P<0.001). However, DCD kidneys that did not experience primary nonfunction functioned as long as DBD kidneys (HR, 1.05; 95% CI, 0.73–1.51; P=0.79). Patient survival of DCD and DBD kidney recipients was equivalent (HR, 1.16; 95% CI, 0.87–1.54; P=0.32). Conclusions. The benefits of DCD kidney transplantation outweigh the increased risk of early graft loss. Expansion of the supply of DCD kidneys is likely to improve the treatment of wait-listed dialysis patients.

A pilot study on the noninvasive evaluation of intestinal damage in celiac disease using I-FABP and L-FABP.

Background and Goals In the clinical management of celiac disease, new noninvasive tools for evaluation of intestinal damage are needed for diagnosis and for follow-up of diet effects. Fatty acid binding proteins (FABP) are potentially useful for this purpose as these are small cytosolic proteins present in enterocytes and sensitive markers for intestinal mucosal damage. First, the distribution and microscopic localization of FABP in the healthy human intestine was examined. Second, levels of circulating FABP were measured in patients with celiac disease before and after introducing a gluten-free diet (GFD) and in healthy controls. Study The distribution and microscopic localization of FABP in normal human intestinal tissue was assessed using surgical intestinal specimens of 39 patients. Circulating levels of intestinal (I)-FABP and liver (L)-FABP were determined in 26 healthy volunteers and 13 patients with biopsy proven celiac disease. Ten of these patients were reevaluated within 1 year after starting GFD. Results I-FABP and L-FABP are predominantly present in the small intestine, mainly the jejunum. Moreover, FABP are expressed in cells on the upper part of the villi, the initial site of destruction in celiac disease. Circulating levels of FABP are significantly elevated in untreated patients with biopsy proven celiac disease compared with healthy controls (I-FABP: 784.7 pg/mL vs. 172.7 pg/mL, P<0.001; L-FABP: 48.4 ng/mL vs. 10.4 ng/mL, P<0.001). In response to GFD, these concentrations normalize. Conclusions Results of this pilot study strongly suggest that FABP can be used as a noninvasive method for assessment of intestinal damage in celiac disease. Besides an additional role in the diagnosis of celiac disease, FABP potentially enable noninvasive monitoring of the GFD effects.

Outcome of Nonheart‐Beating Donor Kidneys with Prolonged Delayed Graft Function after Transplantation

Nonheart‐beating donor (NHBD) kidneys are frequently associated with delayed graft function (DGF), with a deleterious effect on kidney function and allograft survival. The influence and the duration of DGF on the outcome of NHBD kidneys are assessed.

Acute ischemic injury to the renal microvasculature in human kidney transplantation

Increased understanding of the pathophysiology of ischemic acute kidney injury in renal transplantation may lead to novel therapies that improve early graft function. Therefore, we studied the renal microcirculation in ischemically injured kidneys from donors after cardiac death (DCD) and in living donor kidneys with minimal ischemia. During transplant surgery, peritubular capillaries were visualized by sidestream darkfield imaging. Despite a profound reduction in creatinine clearance, total renovascular resistance of DCD kidneys was similar to that of living donor kidneys. In contrast, renal microvascular perfusion in the early reperfusion period was 42% lower in DCD kidneys compared with living donor kidneys, which was accounted for by smaller blood vessel diameters in DCD kidneys. Furthermore, DCD kidneys were characterized by smaller red blood cell exclusion zones in peritubular capillaries and by greater production of syndecan-1 and heparan sulfate (main constituents of the endothelial glycocalyx) compared with living donor kidneys, providing strong evidence for glycocalyx degradation in these kidneys. We conclude that renal ischemia and reperfusion is associated with reduced capillary blood flow and loss of glycocalyx integrity. These findings form the basis for development of novel interventions to prevent ischemic acute kidney injury.

Predictive DNA testing for multiple endocrine neoplasia 2: A therapeutic challenge of prophylactic thyroidectomy in very young children

BACKGROUND Patients with multiple endocrine neoplasia (MEN) type 2 are at risk for early medullary thyroid carcinoma (MTC). Recently, the cloning of the ret oncogene has made it possible to identify patients at risk for MEN 2 syndrome with a high degree of reliability before presenting any symptoms. METHODS Children of families with MEN 2 were screened genetically if one of the parents was a known gene carrier of the RET proto-oncogene. If they were carriers, thyroidectomy was performed. RESULTS The authors report five children with MEN 2 who underwent prophylactic thyroidectomy irrespective of the results of calcitonin screening tests after genetic screening had shown that they were carrier of the RET proto-oncogene. Apart from a temporary hypocalcemia in one, the operations were uneventful. Pathology results showed MTC in three children of one family with MEN 2A at age 2, 3, and 6 years. In two families with MEN 2B the thyroidectomy specimen showed bilateral MTC in a 1-year-old and a 3-year-old child. CONCLUSIONS These findings show that MTC occurs at very young age in children with MEN 2. The authors advocate performing prophylactic thyroidectomy in the first year of life in children with MEN 2B and at age 2 years in children with MEN 2A to obtain an optimal cure rate.