Is beta-trace protein an alternative marker of glomerular filtration rate in liver transplant recipients?

BACKGROUND: Renal insufficiency is common after liver transplantation (LT). The use of creatinine (Crea) as a marker of the glomerular filtration rate (GFR) is limited in patients after LT. Beta-trace protein (BTP), an alternative marker of GFR, is independent of muscle mass and has not been evaluated in LT recipients. AIM: To evaluate BTP as an alternative tool to monitor renal function in LT recipients. METHODS: We determined the diagnostic performance of BTP in comparison to Crea and cystatin C (CysC) in 52 patients, who concomitantly underwent (99m)Tc-DTPA-clearance measurements. Furthermore, we evaluated bias, precision and accuracy of five recently developed BTP-based equations to estimate GFR. RESULTS: The average measured GFR was 51 (46.1; 56.0) ml/min/1.73 m(2). Using a cut-off of 30 ml/min/1.73 m(2) the area under the curve (AUC) was nearly identical for all markers. At a decision point of 60 ml/min/1.73 m(2) BTP showed only a trend towards a higher AUC compared with Crea and CysC (0.806 vs. 0.754 and 0.760, respectively; P>0.2). In comparison to the modification of diet in renal disease-formula (MDRD) only one of five BTP-based equations displayed a significantly higher accuracy within 30% of the measured GFR (84.6 vs. 59.6%; P=0.006). None of these equations showed a significant improvement compared with MDRD with respect to bias and precision. CONCLUSIONS: Beta-trace protein can be used as an alternative diagnostic tool to detect moderate or severe GFR reduction in patients after LT. Furthermore BTP-based equations are able to estimate GFR in LT recipients. However, these equations fail to perform constantly better than the MDRD formula.

Validation of the CKD-EPI formula in patients after renal transplantation.

BACKGROUND: Accurate calculation of glomerular filtration rate (GFR) is crucial in the management of patients after kidney transplantation (KTx). Recently, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula was introduced to estimate GFR in chronic kidney disease patients. However, to date the diagnostic value of this equation remains to be determined in patients after KTx. METHODS: We analysed the CKD-EPI formula in comparison to the re-expressed Modification of Diet in Renal Disease (MDRD) equation in 170 stable patients after renal transplantation. Correlation, bias, precision and accuracy within 30 and 50% of true GFR were determined. GFR was measured by technetium-diethylenetriamine pentaacetic acid clearance [39.6, 95% confidence interval (CI): 37.3-42.0 mL/min/1.73m(2)]. RESULTS: The results for the MDRD and CKD-EPI equations correlated well with GFR (0.82; 0.83, respectively). GFR calculated by MDRD (44.1, 95% CI: 41.6-46.8 mL/min/1.73m(2)) and CKD-EPI (47.7, 95% CI: 44.7-50.7 mL/min/1.73m(2)) overestimated true GFR significantly (P < 0.001). Precision was not significantly different between MDRD and CKD-EPI (10.9 versus 10.0 mL/min/1.73m(2), respectively). Accuracy within 30% of true GFR was significantly higher for MDRD (71.8%) than for CKD-EPI (64.1%, P = 0.0014). Accuracy within 50% of true GFR did not differ significantly (MDRD: 89.4% versus CKD-EPI: 84.7%, P = 0.06). CONCLUSION: The new CKD-EPI formula did not improve the estimation of GFR in Caucasian patients after renal transplantation in this study.

Renal impairment after liver transplantation - a pilot trial of calcineurin inhibitor-free vs. calcineurin inhibitor sparing immunosuppression in patients with mildly impaired renal function after liver transplantation.

OBJECTIVES: Chronic kidney disease is frequent in patients after orthotopic liver transplantation (OLT) and has impact on survival. Patients receiving calcineurin inhibitors (CNI) are at increased risk to develop impaired renal function. Early CNI reduction and concomitant use of mycophenolat mofetil (MMF) has been shown to improve renal function. METHODS: The aim of this trial was to compare dose-reduced CNI/MMF versus CNI-free MMF/prednisone-based treatment in stable patients after OLT with respect to glomerular filtration rate (GFR). 21 patients (GFR 44.9 ' 9.9 mL/min/1.73m2 measured by 99m-Tc-DTPA-clearance, serum creatinine (SCr) 1.5 ' 0.42 mg/dL) were randomized either to exchange CNI for 10 mg prednisone (group 1; n = 8) or to receive CNI at 25% of the initial dose (group 2; n = 13) each in combination with 1000 mg MMF b.i.d. RESULTS: At month 12 mean SCr (-0.3 ' 0.4 mg/dL, p = 0.031) and GFR improved (8.6 ' 13.1 mL/min/ 1.73m superset2, p = 0.015) in group 2 but remained unchanged in group 1. Main side effects were gastroinstestinal symptoms (14.3%) and infections (4.8%). Two biopsy proven, steroid-responsive rejections occurred. In group 1 mean diastolic blood pressure (BP) increased by 11 ' 22 mmHg (p = 0.03). CONCLUSIONS: Reduced dose CNI in combination with MMF but not CNI-free-immunosuppression leads to improvement of GFR in patients with moderately elevated SCr levels after OLT. Addition of steroids resulted in increased diastolic blood pressure presumably counterbalancing the benefits of CNI withdrawal on renal function.

Impairment of long-term graft function after kidney transplantation by intraoperative vascular complications.

OBJECTIVE: Surgical complications in kidney transplantation often demand reoperation and therefore may severely affect graft survival. Major complications can be divided into ureteral and vascular related. Reoperation for ureteral complications is supposed to worsen graft survival, but vascular complications or anastomosis technique has not been evaluated for this issue. PATIENTS AND METHODS: Between 1994 and 2004 260 patients underwent kidney transplantation. All ureterovesical junctions were performed in extravesical technique with ureteral stenting in 132/260 (50.7%) patients. Arterial end-to-side anastomosis was performed routinely except for 13/260 (5%) with end-to-end anastomosis. Mean follow-up was 43 months (0-121) including serum creatinine and ultrasound inter alia. RESULTS: Graft failure rate was 8.1% 12 months and 12.7% 60 months postoperatively. Of the patients, 29/260 (11.5%) underwent reoperation within 30 days after transplantation (stenosis or leakage of the ureterovesical junction: n = 8; vascular complications: n = 10; thrombectomy for graft vein thrombosis: n = 1; evacuation of hematoma: n = 6; nephrectomy for complete graft ischemia: n = 4). Reoperation for vascular-related complications significantly enhances the risk of graft failure (P < 0.05, Cox proportional hazard) compared to urological complications. Arterial end-to-end anastomosis was also found to have a negative impact on graft survival. No correlation between routine ureteral stenting and ureteral stenosis or leakage was found. CONCLUSION: Our data emphasize the importance of vascular complications compared to ureteral ones in kidney transplantation. Resolving 'non-urological' problems successfully, kidney transplantation is a safe procedure in urological hands.

C-reactive protein is a prognostic indicator in patients with perihilar cholangiocarcinoma.

AIM: To evaluate prognostic indicators for the outcome of patients with perihilar extrahepatic cholangiocarcinoma in an unselected cohort. METHODS: We retrospectively analyzed 98 patients with perihilar cholangiocarcinoma. Twenty-three patients (23.5%) underwent tumor resection. Patients with non-resectable tumors underwent either transpapillary or percutaneous transhepatic biliary drainage. Additionally, 32 patients (32.7%) received photodynamic therapy (PDT) and 18 patients (18.4%) systemic chemotherapy. Predefined variables at the time of diagnosis and characteristics considering the mode of treatment were entered into a Cox's proportional hazards model. Included in the analysis were age, tumor stage following the modified Bismuth-Corlette classification, bilirubin, prothrombin time (PT), C-reactive protein (CRP), carbohydrate antigen 19-9 (CA19-9), history of weight loss, surgical resection, chemotherapy and PDT. RESULTS: The Kaplan-Meier estimate of overall median survival was 10.5 (95%CI: 8.4-12.6) mo. In the univariate analysis, low Bismuth stage, low CRP and surgical resection correlated significantly with better survival. In the multivariate analysis, only CRP (P = 0.005) and surgical resection (P = 0.029) were found to be independently predictive of survival in the cohort. Receiver operating characteristic (ROC) analysis identified a CRP level of 11.75 mg/L as the value associated with the highest sensitivity and specificity predicting a survival > 5 mo. Applying Kaplan-Meier analysis, patients with a CRP < 12 mg/L at the time of diagnosis had a significantly longer median survival than patients with higher values (16.2 vs 7.6 mo; P = 0.009). CONCLUSION: This retrospective analysis identified CRP level at the time of diagnosis as a novel indicator for the prognosis of patients with perihilar cholangiocarcinoma. It should be evaluated in future prospective trials on this entity.

Detection of Klatskin's tumor in extrahepatic bile duct strictures using delayed 18F-FDG PET/CT: preliminary results for 22 patient studies.

UNLABELLED: Detection of cholangiocarcinoma in extrahepatic bile duct strictures is a continuing challenge in clinical practice because brush cytology taken at endoscopic retrograde cholangiography has an average sensitivity of 50%. The aim of this study was to evaluate the effectiveness of dual-modality PET/CT using (18)F-FDG for noninvasive differentiation of extrahepatic bile duct strictures. METHODS: Twenty-two PET/CT studies were performed on 20 patients (10 women, 10 men; mean age +/- SD, 63 +/- 14 y) with extrahepatic bile duct strictures on endoscopic retrograde cholangiography. PET imaging was started 101 +/- 22 min after injection of 369 +/- 48 MBq of 18F-FDG. Blood glucose was 100 +/- 20 mg/dL. PET images were reconstructed iteratively with attenuation correction based on a rescaling of the CT image. CT was performed within 1 min before the PET study, with the patient in the same position. CT was used to place a volume of interest 5 cm in diameter at the liver hilus for quantitative evaluation of PET images by means of standardized uptake values (SUVs). RESULTS: Final diagnosis was histologically proven cholangiocarcinoma in 14 cases and benign causes of strictures in 8 cases without evidence of malignancy during a follow-up of 18 +/- 3 mo. All patients with cholangiocarcinoma presented with focal increased uptake in the liver hilus with an SUV of 6.8 +/- 3.3 (range, 3.9-15.8), compared with 2.9 +/- 0.3 (range, 2.5-3.3) in patients with benign causes of strictures (P = 0.003). There was a clear cutoff SUV of 3.6 for detection of malignancy in the liver hilus. CONCLUSION: 18F-FDG PET/CT provided high accuracy for noninvasive detection of perihilar cholangiocarcinoma in extrahepatic bile duct strictures.

Effects of antioxidants and pro-oxidants on cytotoxicity of dihydroartemisinin to Molt-4 human leukemia cells.

BACKGROUND: The objective of the present study was to investigate how oxidative status influences the effectiveness of cytotoxicity of artemisinin towards cancer cells. It is hypothesized that antioxidants would reduce, whereas pro-oxidants would enhance, cytotoxicity. MATERIALS AND METHODS: Molt-4 human leukemia cells were incubated with vitamins C, E, D3, dexamethasone, or hydrogen peroxide alone or in combination with dihydroartemisinin (DHA). Concentrations of these compounds studied were similar to those achievable by oral administration. Viable cell counts were performed before (0 h) and at, 24 and 48 h after treatment. RESULTS: Vitamin C, vitamin D3, dexamethasone, and H2O2 caused significant Molt-4 cell death. Vitamin E caused an increase in Molt-4 cell growth. Vitamin C and vitamin D3 significantly interacted with DHA at the 48-h time point and with H2O2 at both 24-h and 48-h time points. CONCLUSION: Cellular oxidative status could alter the potency of artemisinin in killing cancer cells.

Pulmonary hypertension in patients with chronic kidney disease on dialysis and without dialysis: results of the PEPPER-study.

Pulmonary hypertension (PH) is common in patients with dialysis-dependent chronic kidney disease and is an independent predictor of mortality. However, specific hemodynamics of the pulmonary circulation, changes induced by hemodialysis and characterization into pre- or postcapillary PH have not been evaluated in patients with chronic kidney disease. We assessed consecutive patients with end-stage chronic kidney disease in WHO FC ≥ II with dyspnea unexplained by other causes on hemodialysis (group 1, n = 31) or without dialysis (group 2, n = 31) using right heart catheterization (RHC). In group 1, RHC was performed before and after dialysis. In end-stage chronic kidney disease, prevalence of precapillary PH was 13% (4/31), and postcapillary PH was discovered in 65% (20/31). All four cases of precapillary PH were unmasked after dialysis. In group 2, two cases of precapillary PH were detected (6%), and postcapillary PH was diagnosed in 22 cases (71%). This is the first study examining a large cohort of patients with chronic kidney disease invasively by RHC for the prevalence of PH. The prevalence of precapillary PH was 13% in patients with end-stage kidney disease. That suggests careful screening for precapillary PH in this selected patient population. RHC should be performed after hemodialysis.

Chromatographic behaviour of single cells in a microchannel with dynamic geometry.

We present the design of a microchannel with dynamic geometry that imparts different flow rates to different cells based on their physical properties. This dynamic microchannel is formed between a textured surface and a flexible membrane. As cells flow through the microchannel, the height of the channel oscillates causing periodic entrapment of the larger cells, and as a result, attenuating their velocity relative to the bulk liquid. The smaller cells are not slowed by the moving microstructure, and move synchronously with the bulk liquid. The ability of the dynamic microchannel to selectively attenuate the flow rate of eukaryotic cells is similar to a size-exclusion chromatography column, but with the opposite behavior. The speed of smaller substances is attenuated relative to the larger substances in traditional size-exclusion chromatography columns, whereas the speed of the larger substances that is attenuated in the dynamic microchannel. We verified this property by tracking the flow of single cells through the dynamic microchannel. L1210 mouse lymphoma cells (MLCs), peripheral blood mononuclear cells (PBMCs), and red blood cells (RBCs) were used as model cells. We showed that the flow rate of MLC is slowed by more than 50% compared to PBMCs and RBCs. We characterized the operation of the microchannel by measuring the velocity of each of the three cell types as a function of the pressures used to oscillate the membrane position, as well as the duty cycle of the oscillation.

Creatinine-based glomerular filtration rate estimation in patients with liver disease: the new Chronic Kidney Disease Epidemiology Collaboration equation is not better.

OBJECTIVES: Limitations of serum creatinine in patients with an impaired liver function are well known. The commonly used modification of diet in renal disease (MDRD) equation has a low diagnostic performance to approximate kidney function in patients after liver transplantation (LT) and patients with liver cirrhosis (LC). The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula has been shown to provide a more accurate estimation of kidney function in patients with chronic kidney disease, but studies in patients with liver disease are lacking. METHODS: We evaluated the diagnostic performance of CKD-EPI in comparison with the re-expressed MDRD formula in patients after LT (group 1; n=59) and in patients suffering from LC (group 2; n=44). GFR was measured by 99mTc-diethylenetriamine penta-acetic acid (group 1) and inulin clearance (group 2). Bias, precision, and accuracy as compared with the measured GFR were determined. RESULTS: The measured mean GFR (95% confidence interval) was 52.3 ml/min/1.73 m2 (47.7; 56.9; group 1) and 35.3 ml/min/1.73 m2 (29.12; 41.3; group 2), respectively. In transplanted patients GFR estimation by CKD-EPI and MDRD did not significantly differ with respect to bias (9.7 vs. 4.3 ml/min/1.73 m2), precision (16.9 vs. 15.5 ml/min/1.73 m2) and accuracy (64.4 vs. 69.5% within 30% of 'true GFR'). In patients with LC, both formulae showed a very high bias (42.5 vs. 40.1 ml/min/1.73 m2), a very low precision (20.7 vs. 25.7 ml/min/1.73 m2) and accuracy (6.8 within 30% of the measured GFR in both groups). CONCLUSION: The CKD-EPI equation does not improve the creatinine-based GFR estimation in patients after LT. In patients with LC, both equations should not be applied as they extremely overestimate GFR.

Effects of artemisinin dimers on rat breast cancer cells in vitro and in vivo.

Artemisinin has been shown to be an effective antimalarial and anticancer compound. Dimers of artemisinin have been synthesized and shown to be potent antimalarials compared with monomers. In the present study, we investigated the effect of two artemisinin dimers (dimer-alcohol and dimer-hydrazone) on rat mammary adenocarcinoma cells (MTLn3) in vitro and in vivo compared with that of the artemisinin monomer dihydroartemisinin (DHA). We found that the dimers are considerably more potent than DHA in killing MTLn3 cells in vitro and suppressing the growth of MTLn3 breast tumors in vivo.

First report of an unexpected blind-ending duplication of the ureter as a rare pitfall in kidney transplantation.

We report on the case of an unexpected blind-ending ureter in a kidney transplant. To our knowledge, this is the first report of a blind-ending ureter in kidney transplantation. The recipient was a 60-year-old woman, with a 6-year history of chronic haemodialysis. During the performance of ureterocystostomy, the ureteric stent could not be placed in the renal pelvis as the ureter, surprisingly, was found as blind-ending in the ureteral sheath. Dissecting the ureteral sheath a second shorter ureter was found and used for ureterocystostomy. The histology reported a normal ureter, which led to a thread of connective tissue. The patient had an uneventful recovery; the creatinine was 1.07 mg/dl at discharge from the hospital. It is mandatory for the transplanting surgeon to be aware of the ureteral variations and the surgeon should be trained in the surgical management of these variations. Accuracy should be ensured when exploring the exact anatomy of the donor organ.

Serum levels of beta-trace protein and its association to diuresis in haemodialysis patients.

BACKGROUND: Beta-trace protein (BTP) has been proposed as an alternative endogenous marker of the glomerular filtration rate. However, possible determinants of BTP in ESRD patients undergoing regular renal replacement therapy have not been evaluated. METHODS: Serum levels of BTP, beta-2-microglobulin, creatinine and urea were analysed before and after dialysis treatment in 73 patients [haemodialysis (HD) n=52; haemodiafiltration (HDF) n=21]. Patients were categorized into four groups with residual diuresis (RD)<0.5 l/day (group 1; n=24), 0.5-1 l/day (group 2; n=18), 1.1-1.5 l/day (group 3; n=12) and >1.5 l/day (group 4; n=19). Subsequently RD was compared to pre-treatment levels of BTP. RESULTS: HD treatment did not affect BTP serum levels [pre-treatment 8.1+/-4.1 mg/l (mean+SD) vs post-treatment 7.7+/-4.1 mg/l; -0.6 +/- 16.1%; ns]. However, in 6 out of 21 patients undergoing HDF BTP levels were reduced by more than 20%. Overall, the resulting decrease in serum concentration was minuscule (9.6+/-6.2 vs 8.3+/-4.9 mg/l; -14+/-21.9%; P=0.03). BTP serum levels were tightly associated to RD of the four groups. Comparison of BTP levels showed significant differences between patients of groups 1 vs 3 and 4 as well as 2 vs 4. CONCLUSIONS: BTP serum levels may serve as a surrogate marker for residual renal function since HD and HDF do not exert clinical relevant alterations on them. Furthermore, BTP serum concentrations appear strongly associated to RD.

Can modifications of the MDRD formula improve the estimation of glomerular filtration rate in renal allograft recipients?

BACKGROUND: Two modifications of the MDRD equation [the Mayo Clinic (MC) equation and Rule's refitted (RR) MDRD formula] were proposed to overcome disadvantages of the original MDRD formula to calculate glomerular filtration rate (GFR). Additionally, a correction factor for the original MDRD formula has been introduced to adapt this formula to creatinine values measured by the isotope-dilution mass spectrometry (IDMS) method. Although precise determination of GFR is of central importance in renal transplant recipients, these equations have not been tested in these patients so far. METHODS: Considering the impact of different creatinine calibrations, we analysed the MC equation and the RR-MDRD formula in comparison with the old as well as the re-expressed (IDMS traceable) MDRD equation and the Cockcroft-Gault (C-G) formula in 126 consecutive patients after kidney transplantation with respect to correlation, bias, precision, accuracy and ROC analysis. GFR was determined as technetium-diethylenetriamine pentaacetic acid ((99m)Tc-DTPA-clearance). RESULTS: After adjustment to IDMS creatinine determination, the performance of the re-expressed MDRD formula improved considerably in comparison to the original MDRD equation. In comparison with the re-expressed MDRD formula bias of the MC formula and the RR-MDRD formula were significantly smaller (2.31 and -0.35 vs 3.82 ml/min/1.73 m(2)). However, precision and correlation of these formulae did not differ significantly from one another, but all equations showed a higher precision than the C-G formula (P < or = 0.006 each). The accuracies within 30% of true GFR of the MC (79.4%) and the RR-MDRD equation (84.9%) were significantly higher than those of the re-expressed MDRD formula (72.2%; P < 0.03). CONCLUSION: In comparison to the original and the re-expressed MDRD formula, calculation of GFR by the MC equation and the RR-MDRD formula led to improved diagnostic performance in renal transplant recipients after adjustment of creatinine. In quotidian work both formulae can be applied to these patients. Nonetheless, to determine GFR exactly, gold standard techniques are mandatory.

Estimation of glomerular filtration rates after orthotopic liver transplantation: Evaluation of cystatin C-based equations.

Early detection of renal dysfunction in patients after orthotopic liver transplantation is important. Creatinine-based equations to estimate glomerular filtration rate (GFR) were found to be less accurate in liver transplant recipients than in their original populations. Since cystatin C (CysC) is independent from muscle mass and hepatic biosynthesis, we evaluated the diagnostic accuracy of 3 CysC-based equations (Larson, Hoek, and Filler formulae) that are based on the same CysC method as that of our center in comparison to the abbreviated creatinine-based modification of diet in renal disease (MDRD) formula in 59 liver transplant recipients. "True GFR" was measured by 99mTc-diethylene triamine pentaacetic acid ((99m)Tc-DTPA) clearance. Neither correlation with the GFR (correlation coefficients: 0.594-0.640) nor precision (root mean square error: 15.7-18.17 mL/min/1.73 m(2)) differed significantly between the tested formulae. The biases of the Hoek and Larsson formulae were significantly smaller than those of the MDRD and Filler equations (-0.1 and -2.3 vs. 10.1 and 7.9 mL/min/1.73 m(2), respectively; P

Prediction of glomerular filtration rate in renal transplant recipients: cystatin C or modification of diet in renal disease equation?

BACKGROUND: To overcome disadvantages of serum creatinine two strategies have been suggested to identify patients with reduced glomerular filtration rate (GFR). On the one hand, the Modification of Diet in Renal Disease (MDRD) equation is now recommended to classify the stage of chronic kidney disease. On the other hand, cystatin C (Cys C) has been investigated in numerous studies, finding a higher sensitivity than creatinine in detecting diminished GFR. To date, no comparison of both strategies in patients after renal transplantation has been performed. METHODS: One hundred and five consecutive renal transplant recipients underwent (99m)Tc-DTPA-- clearance measurement. Simultaneously, MDRD estimates were calculated and Cys C serum levels were determined. ROC analyses were performed at different decision points from 20 to 70 mL/min/1.73 m(2). RESULTS: Although the area under the curve did not differ significantly between MDRD and Cys C within the tested GFR range, the AUC for Cys C tended to be higher when GFR exceeded 55 mL/min/1.73 m(2). A significantly higher diagnostic accuracy for Cys C compared with MDRD (p = 0.045 at 65 mL/min/1.73 m(2)) was found when investigating the subgroup of patients with well-functioning grafts (GFR>40 mL/min/1.73 m(2)). CONCLUSION: MDRD equation is equivalent to Cys C measurement in renal transplant recipients. As availability of MDRD is superior to Cys C, we recommend GFR estimation using the MDRD equation. Nevertheless, Cys C may serve as a confirmation test of high MDRD estimates in patients with well-functioning grafts because of superior accuracy in these patients.