Hyperhomocysteinemia: a trigger for complement-mediated TMA?

A 34-year-old man of North African descent was referred to the emergency department because of malignant hypertension (220/113 mmHg), acute visual disturbances and acute kidney failure (serum creatinine 14.0 mg/dL). Blood analysis was compatible with thrombotic microangiopathy (TMA). Kidney biopsy confirmed this diagnosis with histological changes including intimal edema, arteriolar thrombi, and severe tubulointerstitial damage. Fundoscopy showed hypertensive retinopathy stage IV. Subsequent biochemical screening revealed normal complement testing and a marked elevation in homocysteine concentration (161 µmol/L; normal value 7-15 µmol/L). Other secondary causes of TMA were excluded. Further genetic testing for cobalamin C (cblC) deficiency showed no pathogenic mutations in the MMACHC gene. However, a homozygous c.665C>T polymorphism (NM_005957.4) in the methylenetetrahydrofolate reductase (MTHFR) gene was found explaining the severe hyperhomocysteinemia due to reduced activity of MTHFR. Additional genetic testing for alternative complement pathway proteins showed mutations in the genes encoding factor H and factor B, both categorized as possibly pathogenic using mutation prediction software. This is the first described case of TMA in a patient with severe hyperhomocysteinemia caused by a genetic defect other than cblC. We postulate that endothelial damage due to hyperhomocysteinemia and hypertension could have triggered the TMA episode in this patient with two possible predisposing pathogenic mutations in the alternative complement pathway. Furthermore, our case demonstrates the need for complete full diagnostic testing in patients with TMA.

Postconditioning effects of argon or xenon on early graft function in a porcine model of kidney autotransplantation.

BACKGROUND: Ischaemia-reperfusion injury is inevitable during renal transplantation and can lead to delayed graft function and primary non-function. Preconditioning, reconditioning and postconditioning with argon and xenon protects against renal ischaemia-reperfusion injury in rodent models. The hypothesis that postconditioning with argon or xenon inhalation would improve graft function in a porcine renal autotransplant model was tested. METHODS: Pigs (n = 6 per group) underwent left nephrectomy after 60 min of warm ischaemia (renal artery and vein clamping). The procured kidney was autotransplanted in a separate procedure after 18 h of cold storage, immediately after a right nephrectomy. Upon reperfusion, pigs were randomized to inhalation of control gas (70 per cent nitrogen and 30 per cent oxygen), argon (70 per cent and 30 per cent oxygen) or xenon (70 per cent and 30 per cent oxygen) for 2 h. The primary outcome parameter was peak plasma creatinine; secondary outcome parameters included further markers of graft function (creatinine course, urine output), graft injury (aspartate aminotransferase, heart-type fatty acid-binding protein, histology), apoptosis and autophagy (western blot, terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) staining), inflammatory mediators and markers of cell survival/growth (mRNA and tissue protein quantification), and animal survival. Results are presented as median (i.q.r.). ANOVA and Kruskal-Wallis tests were used where indicated. RESULTS: Peak plasma creatinine levels were similar between the groups: control 20·8 (16·4-23·1) mg/dl, argon 21·4 (17·1-24·9) mg/dl and xenon 19·4 (17·5-21·0) mg/dl (P = 0·607). Xenon was associated with an increase in autophagy and proapoptotic markers. Creatinine course, urine output, injury markers, histology, survival and inflammatory mediators were not affected by the intervention. CONCLUSION: Postconditioning with argon or xenon did not improve kidney graft function in this experimental model. Surgical relevance Ischaemia-reperfusion injury is inevitable during renal transplantation and can lead to delayed graft function and primary non-function. Based on mainly small animal experiments, noble gases (argon and xenon) have been proposed to minimize this ischaemia-reperfusion injury and improve outcomes after transplantation. The hypothesis that postconditioning with argon or xenon inhalation would improve graft function was tested in a porcine kidney autotransplantation model. The peak plasma creatinine concentration was similar in the control, argon and xenon groups. No other secondary outcome parameters, including animal survival, were affected by the intervention. Xenon was associated with an increase in autophagy and proapoptotic markers. Despite promising results in small animal models, postconditioning with argon or xenon in a translational model of kidney autotransplantation was not beneficial. Clinical trials would require better results.

Esophageal Cancer: Associations With (pN+) Lymph Node Metastases.

OBJECTIVES: To identify the associations of lymph node metastases (pN+), number of positive nodes, and pN subclassification with cancer, treatment, patient, geographic, and institutional variables, and to recommend extent of lymphadenectomy needed to accurately detect pN+ for esophageal cancer. SUMMARY BACKGROUND DATA: Limited data and traditional analytic techniques have precluded identifying intricate associations of pN+ with other cancer, treatment, and patient characteristics. METHODS: Data on 5806 esophagectomy patients from the Worldwide Esophageal Cancer Collaboration were analyzed by Random Forest machine learning techniques. RESULTS: pN+, number of positive nodes, and pN subclassification were associated with increasing depth of cancer invasion (pT), increasing cancer length, decreasing cancer differentiation (G), and more regional lymph nodes resected. Lymphadenectomy necessary to accurately detect pN+ is 60 for shorter, well-differentiated cancers (<2.5 cm) and 20 for longer, poorly differentiated ones. CONCLUSIONS: In esophageal cancer, pN+, increasing number of positive nodes, and increasing pN classification are associated with deeper invading, longer, and poorly differentiated cancers. Consequently, if the goal of lymphadenectomy is to accurately define pN+ status of such cancers, few nodes need to be removed. Conversely, superficial, shorter, and well-differentiated cancers require a more extensive lymphadenectomy to accurately define pN+ status.

High Intrapatient Variability of Tacrolimus Concentrations Predicts Accelerated Progression of Chronic Histologic Lesions in Renal Recipients.

High intrapatient variability (IPV) of tacrolimus concentrations is increasingly recognized as a predictor of poor outcome in solid organ recipients. How it relates to evolution of histology has not been explored. We analyzed tacrolimus IPV using the coefficient of variability (CV) from months 6-12 after transplantation in a cohort of 220 renal recipients for whom paired protocol biopsies at 3 mo and 2 years were available. Recipients in the highest CV tertile had an increased risk of moderate to severe fibrosis and tubular atrophy by 2 years compared with the low-IPV tertile (odds ratio [OR] 2.47, 95% confidence interval [CI] 1.09-5.60, p = 0.031; and OR 2.40, 95% CI 1.03-5.60, p = 0.043, respectively). Other predictors were donor age, severity of chronic lesions at 3 mo, and presence of borderline or subclinical rejection at 3 mo. Chronicity score increased significantly more in the high CV tertile group than in the middle and low tertiles (mean increase 1.97 ± 2.03 vs. 1.18 ± 2.44 and 1.12 ± 1.80, respectively; p < 0.05). CV did not predict evolution of renal function, which did not deteriorate within the 2-year follow-up period. These results indicate that high IPV is related to accelerated progression of chronic histologic lesions before any evidence of renal dysfunction.

RANK/OPG ratio of expression in primary clear-cell renal cell carcinoma is associated with bone metastasis and prognosis in patients treated with anti-VEGFR-TKIs.

BACKGROUND: Bone metastases (BMs) are associated with poor outcome in metastatic clear-cell renal carcinoma (m-ccRCC) treated with anti-vascular endothelial growth factor tyrosine kinase inhibitors (anti-VEGFR-TKIs). We aimed to investigate whether expression in the primary tumour of genes involved in the development of BM is associated with outcome in m-ccRCC patients treated with anti-VEGFR-TKIs. METHODS: Metastatic clear-cell renal cell carcinoma patients with available fresh-frozen tumour and treated with anti-VEGFR-TKIs. Quantitative real-time PCR (qRT-PCR) for receptor activator of NF-kB (RANK), RANK-ligand (RANKL), osteoprotegerin (OPG), the proto-oncogene SRC and DKK1 (Dickkopf WNT signalling pathway inhibitor-1). Time-to-event analysis by Kaplan-Meier estimates and Cox regression. RESULTS: We included 129 m-ccRCC patients treated between 2005 and 2013. An elevated RANK/OPG ratio was associated with shorter median time to metastasis (HR 0.50 (95% CI 0.29-0.87); P=0.014), shorter time to BM (HR 0.54 (95% CI 0.31-0.97); P=0.037), shorter median overall survival (mOS) since initial diagnosis (HR 2.27 (95% CI 1.44-3.60); P=0.0001), shorter median progression-free survival (HR 0.44 (95% CI 0.28-0.71); P=0.001) and mOS (HR 0.31 (95% CI 0.19-0.52); P<0.0001) on first-line anti-VEGFR-TKIs in the metastatic setting. Higher RANK expression was associated with shorter mOS on first-line anti-VEGFR-TKIs (HR 0.46 (95% CI 0.29-0.73); P=0.001). CONCLUSIONS: RANK/OPG ratio of expression in primary ccRCC is associated with BM and prognosis in patients treated with anti-VEGFR-TKIs. Prospective validation is warranted.

The effect of anastomosis time on outcome in recipients of kidneys donated after brain death: a cohort study.

Whether warm ischemia during the time to complete the vascular anastomoses determines renal allograft function has not been investigated systematically. We investigated the effect of anastomosis time on allograft outcome in 669 first, single kidney transplantations from brain-dead donors. Anastomosis time independently increased the risk of delayed graft function (odds ratio per minute [OR] 1.05, 95% confidence interval [CI] 1.02-1.07, p < 0.001) and independently impaired allograft function after transplantation (p = 0.009, mixed-models repeated-measures analysis). In a subgroup of transplant recipients, protocol-specified biopsies at 3 months (n = 186), 1 year (n = 189), and 2 years (n = 153) were blindly reviewed. Prolonged anastomosis time independently increased the risk of interstitial fibrosis and tubular atrophy on these protocol-specified biopsies posttransplant (p < 0.001, generalized linear models). In conclusion, prolonged anastomosis time is not only detrimental for renal allograft outcome immediately after transplantation, also longer-term allograft function and histology are affected by the duration of this warm ischemia.

Henoch-Schönlein Purpura complicated with major gastro-intestinal hemorrhage.

We report a case of Henoch-Schönlein Purpura in a 83-year old patient. The patient presented with a purpuric rash and arthralgia. During admission, he developed hematochezia and acute kidney injury. Because of protracted gastro-intestinal bleeding after initiating therapy with methylprednisolone and ileocaecal resection, azathioprine was started. Gastro-intestinal bleeding resolved, and renal function normalized. We present the clinical and pathological findings of Henoch-Schönlein Purpura, focusing on gastro-intestinal manifestations.

Post-streptococcal glomerulonephritis: not an extinct disease!

We present the case of a 29-year-old type 1 diabetic patient with the diagnosis of acute post-streptococcal glomerulonephritis. The incidence of this textbook example of acute glomerulonephritis has dropped dramatically in the developed world during the past decades due to the more widespread use of antibiotics. However, the present case illustrates that it is not an extinct disease and that clinicians should be aware of this entity. Particular attention is needed for the fact that the clinical context in which the disease occurs may be different from the classical "post-angina" presentation.

Does 11C-choline PET-CT contribute to multiparametric MRI for prostate cancer localisation?

BACKGROUND AND PURPOSE: The aim of this work was to determine whether 11C-choline positron emission tomography (PET)-computed tomography (CT) makes a positive contribution to multiparametric magnetic resonance imaging (MRI) for localisation of intraprostatic tumour nodules. PATIENTS AND METHODS: A total of 73 patients with biopsy-proven intermediate- and high-risk prostate cancer were enrolled in a prospective imaging study consisting of T2-weighted (T2w), dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) MRI and 11C-choline PET-CT before radical prostatectomy. Cancerous regions were delineated on the whole-mount prostatectomy sections and on the different MRI modalities and analysed in 24 segments per patient (3 sections, 8 segments each). To analyse PET-CT images, standardized uptake values (SUV) were calculated per segment. RESULTS: In total, 1,752 segments were analyzed of which 708 (40.4%) were found to be malignant. A high specificity (94.7, 93.6 and 92.2%) but relatively low sensitivity (31.2, 24.9 and 44.1%) for tumour localisation was obtained with T2w, DCE and DW MRI, respectively. Sensitivity values significantly increased when combining all MRI modalities (57.2%). For PET-CT, mean SUVmax of malignant octants was significantly higher than mean SUVmax of benign octants (3.68±1.30 vs. 3.12±1.02, p<0.0001). In terms of accuracy, the benefit of adding PET-CT to (multiparametric) MRI was less than 1%. CONCLUSION: The additional value of 11C-choline PET-CT to MRI in localising intraprostatic tumour nodules is limited, especially when multiparametric MRI is used.

The transcription intermediary factor 1ß coactivates the androgen receptor.

The androgen receptor (AR) is a ligand-inducible transcription factor. Its transcription activation domain consists of the two transcription activation units called Tau-1 and Tau- 5. Tau-5 interacts with p160 coactivators like the transcription intermediary factor 2 (TIF2), which in their turn recruit histone modifiers and chromatin-remodelling complexes. The mechanism of action of Tau-1, however, remains elusive. Here, we demonstrate that transcription intermediary factor 1ß (TIF1ß) can induce the activity of the AR up to five fold when tested in vitro. Although there is no evidence for direct interactions between TIF1ß and AR, mutation studies show that the activity of TIF1ß depends on the integrity of Tau-1 in AR on the one hand, and the so-called tripartite motif domain in TIF1ß on the other. Surprisingly, the coactivation by TIF1ß via Tau-1 seems additive rather than cooperative with the AR coactivation by TIF2. Some mutations naturally occurring in androgen-insensitivity syndrome patients that reside in Tau-1 seem to impair the TIF1ß coactivation of the AR, indicating that TIF1ß could also be relevant for the in vivo androgen response in humans. Moreover, since TIF1ß is well expressed in prostate cancer cells, its functional interaction with androgen signalling could in the long run be a therapeutic target for this disease.

Single-nucleotide polymorphisms associated with outcome in metastatic renal cell carcinoma treated with sunitinib.

BACKGROUND: There are no validated markers that predict response in metastatic renal cell cancer (RCC) patients treated with sunitinib. We aim to study the impact of single-nucleotide polymorphisms (SNPs) that have recently been proposed as predictors of outcome to anti-VEGF-targeted therapy in metastatic RCC in an independent cohort of patients. METHODS: We genotyped 16 key SNPs in 10 genes involved in sunitinib pharmacokinetics, pharmacodynamics and VEGF-independent angiogenesis in patients with metastatic clear-cell RCC treated with sunitinib as the first-line targeted therapy. Association between SNPs, progression-free survival (PFS) and overall survival (OS) were studied by multivariate Cox regression using relevant clinical factors associated with PFS and OS as covariates. RESULTS: In a series of 88 patients, both PFS and OS were associated significantly with SNP rs1128503 in ABCB1 (P=0.027 and P=0.025), rs4073054 in NR1/3 (P=0.025 and P=0.035) and rs307821 in VEGFR3 (P=0.032 and P=0.011). Progression-free survival alone was associated with rs2981582 in FGFR2 (P=0.031) and rs2276707 in NR1/2 (P=0.047), whereas OS alone was associated with rs2307424 in NR1/3 (P=0.048) and rs307826 in VEGFR3 (P=0.013). CONCLUSION: Our results confirm former communications regarding the association between SNPs in ABCB1, NR1/2, NR1/3 and VEGFR3 and sunitinib outcome in clear-cell RCC. Prospective validation of these SNPs is now required.

Chronic histological damage in early indication biopsies is an independent risk factor for late renal allograft failure.

The impact of early histological lesions of renal allografts on long-term graft survival remains unclear. We included all renal allograft recipients transplanted at a single center from 1991 to 2001 (N = 1197). All indication biopsies performed within the first year after transplantation were rescored according to the current Banff classification. Mean follow-up time was 14.8 ± 2.80 years. In multivariate Cox proportional hazards analysis, arteriolar hyalinosis and transplant glomerulopathy were independently associated with death-censored graft survival, adjusted for baseline demographic covariates. Arteriolar hyalinosis correlated with interstitial fibrosis, tubular atrophy, mesangial matrix increase, vascular intimal thickening and glomerulosclerosis. Clustering of the patients according to these chronic lesions, reflecting the global burden of chronic injury, associated better with long-term graft survival than each of the chronic lesions separately. Early chronic histological damage was an independent risk factor for late graft loss, irrespective whether a specific, progressive disease was diagnosed or not, while T cell-mediated rejection did not. We conclude that individual chronic lesions like arteriolar hyalinosis, tubular atrophy, interstitial fibrosis, glomerulosclerosis, mesangial matrix increase and vascular intimal thickening cannot be seen as individual entities. The global burden of early chronic histological damage within the first year after transplantation importantly affects the fate of the allografts.

Concomitant oral tyrosine kinase inhibitors and bisphosphonates in advanced renal cell carcinoma with bone metastases.

BACKGROUND: The presence of bone metastases in patients with metastatic renal cell carcinoma treated with oral tyrosine kinase inhibitors (TKIs) is associated with poorer outcome as compared with patients without bone involvement. Concomitant bisphosphonates could probably improve outcomes but also induce osteonecrosis of the jaw (ONJ). METHODS: Retrospective study on all the renal cell carcinoma patients with bone metastases treated with sunitinib or sorafenib between November 2005 and June 2012 at the University Hospitals Leuven and AZ Groeninge in Kortrijk. RESULTS: Seventy-six patients were included in the outcome analysis: 49 treated with concomitant bisphosphonates, 27 with TKI alone. Both groups were well balanced in terms of prognostic and predictive markers. Response rate (38% vs 16% partial responses, P=0.028), median progression-free survival (7.0 vs 4.0 months, P=0.0011) and median overall survival (17.0 vs 7.0 months, P=0.022) were significantly better in patients receiving bisphosphonates. The incidence of ONJ was 10% in patients treated with TKI and bisphosphonates. CONCLUSION: Concomitant use of bisphosphonates and TKI in renal cell carcinoma patients with bone involvement probably improves treatment efficacy, to be confirmed by prospective studies, but is associated with a high incidence of ONJ.

The prognostic relevance of tumor hypoxia markers in resected carcinoma of the gallbladder.

BACKGROUND: Intratumoral hypoxia has been suggested to drive more aggressive tumor behavior. Our aim was to define whether markers of tumor hypoxia are predictors of outcome in patients with gallbladder carcinoma. PATIENTS AND METHODS: From 1996 to 2006, 34 patients underwent resection for gallbladder carcinoma. The median follow-up was 12.6 months. Immunohistochemical stains for VEGF, HIF1α, GLUT1, GLUT3, CA9 and EGFR were performed on archival tissue. Immunohistochemical results were correlated with clinical and histopathological parameters. Cumulative overall survival (OS) rates were estimated using the Kaplan-Meier method. Multivariable Cox regression models were used to identify predictors of OS. RESULTS: The median OS was 11.9 (IQR: 3.4-22.0) months. Ubiquitous VEGF staining was observed in all gallbladder carcinomas. High (>50% of tumor cells) EGFR expression was associated with worse OS (p0.03). CA9 expression was less prevalent in poorly differentiated tumors (p0.02). GLUT3, GLUT1 and HIF1α expression were not associated with survival, but did correlate with the presence of lymph node metastasis (p0.02), tumor differentiation (p0.04) and tumor stage (p0.03) respectively. High EGFR expression, TNM stage and preoperative serum CA19.9 were retained as independent predictors of OS in multivariable analysis. CONCLUSION: In gallbladder cancer high expression of EGFR is an independent predictor of survival.

Living related intestinal transplantation for Churg-Strauss syndrome: a case report.

Exceptionally, gastrointestinal involvement of Churg-Strauss syndrome (CSS) may require extensive bowel resection resulting in a short bowel syndrome. Living related intestinal transplantation (IT) has emerged as an alternative to deceased-donor IT in the management of patients with irreversible short bowel syndrome. Herein, we have presented a 35-year-old patient with isolated intestinal involvement of CSS lesions refractory to steroids and azathioprine requiring multiple abdominal resections resulting in an ultrashort bowel syndrome. A living related IT (from the mother) was performed. She underwent several acute rejection episodes treated with additional immunosuppressive therapy. Despite higher doses of immunosuppression, these repeated acute rejection episodes eventually evolved into a syndrome of chronic allograft rejection. Eventually, owing to her poor general condition and to avoid life-threatening infections, transplantectomy was inevitable. Recent immunologic studies indicate that peripheral mononuclear cells from patients with CSS secrete large amounts of T-helper type 1 and 2 cytokines. It is likely that patients with CSS are at higher risk for acute and chronic rejection after transplantation.

Thrombotic microangiopathy following intestinal transplantation: a single center experience.

BACKGROUND: Transplant-related thrombotic microangiopathy (TMA) is a well-recognized complication of all types of transplantations. Despite its known relationship with immunosuppressive therapy, only a few cases have been reported following intestinal transplantation. METHODS: We retrospectively reviewed the medical files of nine consecutive intestinal transplant patients between 2000 and 2008. RESULTS: The diagnosis of TMA was established in 3 patients (33%). At diagnosis the immunosuppressive therapy consisted of tacrolimus (n = 3), combined with azathioprine (n = 1) or sirolimus (n = 2) and steroids (n = 2). The median time between transplantation and TMA was 104 days (range, 55-167 days). Levels of ADAMTS13, a von Willebrand protease, were within normal ranges in all 3 patients. Treatment consisted of stopping/tapering of tacrolimus, together with initiation of plasma therapy, leading to complete remission in all 3 patients. During further follow-up, all 3 patients showed severe graft rejection necessitating more profound immunosuppressive therapy, leading to graft loss in 1 patient and infection-related death in the 2 others. At a median follow-up of 52 months (range, 9-100 months) all remaining TMA-free patients (n = 6) were alive with functioning grafts under minimal immunosuppression. CONCLUSION: Herein we have described 3 intestinal transplant patients who were diagnosed with transplantation-related TMA. Despite excellent disease control the final outcomes were dismal, which clearly contrasts with the outcome among TMA-free patients, who were all well with functioning grafts at last follow-up.

Balancing efficacy and toxicity of kidney transplant immunosuppression.

Late renal allograft loss is mainly the result of progressive histological damage. Both underimmunosuppression (rejection phenomena) and overimmunosuppression (calcineurin inhibitor nephrotoxicity) contribute to the progression of chronic histological damage. The current study was performed to elucidate the complementary impact of immune and nonimmune phenomena on renal allograft histology and function. By performing protocol biopsies, it was demonstrated that clinical and subclinical acute cellular rejection phenomena continue to play important roles, despite the use of the powerful combination of tacrolimus, mycophenolate mofetil, and steroids. Next to immune phenomena, the importance of nonimmune factors in renal allograft histological evolution was shown in protocol biopsy studies. Both in adult and in pediatric renal allograft recipients, the characteristics of the donor kidney (donor age, size discrepancy) appeared to be major determinants of the histological and functional evolution. This impact of donor characteristics was not only important in the immediate peritransplantation period, it was also shown that higher donor age increased the risk for progressive posttransplant histological injury and calcineurin inhibitor nephrotoxicity. Systemic levels of tacrolimus, if kept within a relatively narrow target window, were not associated with a risk for calcineurin inhibitor nephrotoxicity. However, we observed a significant association between renal allograft histology and P-glycoprotein (ABCB1) gene polymorphisms and expression, suggesting a role of this protein in the individual susceptibility to calcineurin inhibitor nephrotoxicity. Finally, the interplay between immune and nonimmune phenomena was demonstrated by the association between donor origin (deceased versus living) and local renal complement gene expression, by using whole-genome expression microarrays.