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Chronic kidney disease (CKD) represents a global public health problem with high disease related morbidity and mortality. Since CKD etiology is heterogeneous, early recognition of patients at risk for progressive kidney injury is important. Here, we evaluated the tubular epithelial derived glycoprotein dickkopf-3 (DKK3) as a urinary marker for the identification of progressive kidney injury in a non-CKD cohort of patients with chronic obstructive pulmonary disease (COPD) and in an experimental model. In COSYCONET, a prospective multicenter trial comprising 2,314 patients with stable COPD (follow-up 37.1 months), baseline urinary DKK3, proteinuria and estimated glomerular filtration rate (eGFR) were tested for their association with the risk of declining eGFR and the COPD marker, forced expiratory volume in one second. Baseline urinary DKK3 but not proteinuria or eGFR identified patients with a significantly higher risk for over a 10% (odds ratio: 1.54, 95% confidence interval: 1.13-2.08) and over a 20% (2.59: 1.28-5.25) decline of eGFR during follow-up. In particular, DKK3 was associated with a significantly higher risk for declining eGFR in patients with eGFR over 90 ml/min/1.73m2 and proteinuria under 30 mg/g. DKK3 was also associated with declining COPD marker (2.90: 1.70-4.68). The impact of DKK3 was further explored in wild-type and Dkk3-/- mice subjected to cigarette smoke-induced lung injury combined with a CKD model. In this model, genetic abrogation of DKK3 resulted in reduced pulmonary inflammation and preserved kidney function. Thus, our data highlight urinary DKK3 as a possible marker for early identification of patients with silent progressive CKD and for adverse outcomes in patients with COPD.

Cardiac surgery is associated with a high risk of postoperative acute kidney injury (AKI) and subsequent loss of kidney function. We explored the clinical utility of urinary dickkopf-3 (DKK3), a renal tubular stress marker, for preoperative identification of patients at risk for AKI and subsequent kidney function loss.This observational cohort study included patients who had cardiac surgery in a derivation cohort and those who had cardiac surgery in a validation cohort (RenalRIP trial). The study comprised consecutive patients who had elective cardiac surgery at the Saarland University Medical Centre (Homburg, Germany; derivation cohort) and those undergoing elective cardiac surgery (selected on the basis of a Cleveland Clinical Foundation score of 6 or higher) who were enrolled in the prospective RenalRIP multicentre trial (validation cohort) and who were randomly assigned to remote ischaemic preconditioning or a sham procedure. The association between the ratio of preoperative urinary concentrations of DKK3 to creatinine (DKK3:creatinine) and postoperative AKI, defined according to the Kidney Disease Improving Global Outcomes criteria, and subsequent kidney function loss, as determined by estimated glomerular filtration rate, was assessed.In the 733 patient in the derivation cohort, urinary concentrations of DKK3 to creatinine that were higher than 471 pg/mg were associated with significantly increased risk for AKI (odds ratio [OR] 1·65, 95% CI 1·10-2·47, p=0·015), independent of baseline kidney function. Compared with clinical and other laboratory measurements, urinary concentrations of DKK3:creatinine significantly improved AKI prediction (net reclassification improvement 0·32, 95% CI 0·23-0·42, p0·0001). High urinary DKK3:creatinine concentrations were independently associated with significantly lower kidney function at hospital discharge and after a median follow-up of 820 days (IQR 733-910). In the RenalRIP trial, preoperative urinary DKK3:creatinine concentrations higher than 471 pg/mg were associated with a significantly higher risk for AKI (OR 1·94, 95% CI 1·08-3·47, p=0·026), persistent renal dysfunction (OR 6·67, 1·67-26·61, p=0·0072), and dialysis dependency (OR 13·57, 1·50-122·77, p=0·020) after 90 days compared with DKK3:creatinine concentrations of 471 pg/mg or less. Urinary DKK3:creatinine concentrations higher than 471 pg/mg were associated with significantly higher risk for AKI (OR 2·79, 95% CI 1·45-5·37) and persistent renal dysfunction (OR 3·82, 1·32-11·05) only in patients having a sham procedure, but not remote ischaemic preconditioning (AKI OR 1·35, 0·76-2·39 and persistent renal dysfunction OR 1·05, 0·12-9·45).Preoperative urinary DKK3 is an independent predictor for postoperative AKI and for subsequent loss of kidney function. Urinary DKK3 might aid in the identification of patients in whom preventive treatment strategies are effective.No study funding.

Background The individual course of CKD may vary, and improved methods for identifying which patients will experience short-term eGFR loss are needed. Assessing urinary Dickkopf-3 (DKK3), a stress-induced tubular epithelia–derived profibrotic glycoprotein, may provide information about ongoing tubulointerstitial fibrosis and short-term eGFR loss. Methods To investigate urinary DKK3’s potential as a biomarker of short-term eGFR loss (over 12 months), we prospectively assessed eGFR and urinary DKK3 levels in patients with CKD of various etiologies at baseline and annual follow-ups. We also measured urinary DKK3 in a general population sample and patients with diagnostic kidney biopsies or IgA nephropathy under treatment. Results Median urinary DKK3-to-creatinine concentration at baseline was significantly higher in patients with CKD than the general population sample (431 versus 33 pg/mg). In the CKD cohort, having a urinary DKK3-to-creatinine level >4000 pg/mg was independently and significantly associated after multiple adjustments with mean annual decline in eGFR of 7.6% over 12 months. Urinary DKK3 significantly improved prediction of kidney function decline compared with eGFR or albuminuria alone. Urinary DKK3-to-creatinine levels were related to the extent of tubulointerstitial fibrosis in kidney biopsies. In patients with IgA nephropathy, a rise in urinary DKK3 was associated with significant eGFR decline within 6 months, whereas stable or decreasing urinary DKK3 indicated a more favorable course. Conclusions Urinary DKK3 levels identify patients at high risk for eGFR decline over the next 12 months regardless of the cause of kidney injury and beyond established biomarkers, potentially providing a tool to monitor CKD progression and assess effects of interventions.

In this study we present novel bispecific antibodies that simultaneously target the insulin-like growth factor receptor type I (IGF-1R) and epidermal growth factor receptor (EGFR). For this purpose disulfide stabilized scFv domains of the EGFR/ADCC antibody GA201 were fused via serine-glycine connectors to the C-terminus of the heavy (XGFR2) or light chain (XGFR4), or the N-termini of the light (XGFR5) or heavy chain (XGFR3) of the IGF-1R antibody R1507 as parental IgG1 antibody. The resulting bispecific IGF-1R-EGFR antibodies XGFR2, XGFR3 and XGFR4 were successfully generated with yields and stability comparable to conventional IgG1 antibodies. They effectively inhibited IGF-1R and EGFR phosphorylation and 3D proliferation of H322M and H460M2 tumor cells, induced strong down-modulation of IGF-1R as well as enhanced EGFR down-modulation compared to the parental EGFR antibody GA201 and were ADCC competent. The bispecific XGFR derivatives showed a strong format dependent influence of N- or C-terminal heavy and light chain scFv attachment on ADCC activity and an increase in receptor downregulation over the parental combination in vitro. XGFR2 and XGFR4 were selected for in vivo evaluation and showed potent anti-tumoral efficacy comparable to the combination of monospecific IGF-1R and EGFR antibodies in subcutaneous BxPC3 and H322M xenograft models. In summary, we have managed to overcome issues of stability and productivity of bispecific antibodies, discovered important antibody fusion protein design related differences on ADCC activity and receptor downmodulation and show that IGF-1R-EGFR antibodies represent an attractive therapeutic strategy to simultaneously target two key components de-regulated in multiple cancer types, with the ultimate goal to avoid the formation of resistance to therapy.

Quercetin (QC), a polyphenolic compound widely distributed in fruits and vegetables has recently gained interest due to its cisplatin (CP) sensitizing properties in cancer cells. It is currently unknown, whether quercetin also increases the susceptibility of the kidneys to cisplatin toxicity. We studied the effects of various bioflavonoids on CP toxicity in an in vitro model of cultured tubular epithelial cells (LLC-PK1). Viability of LLC-PK1 cells, as assessed by lactate dehydrogenase (LDH) release and MTT-test, was affected by CP (100-400 microM) in a time and dose dependent fashion. Pretreatment of cells with QC for 3 h significantly reduced the extent of cell damage. The protective activity of QC was concentration dependent, starting at 10-25 microM and reaching a plateau between 50 and 100 microM. Other bioflavonoids (catechin, silibinin, rutin) did not diminish cellular injury, even at higher concentrations (100-500 microM). Quercetin itself showed some intrinsic cytotoxicity at concentrations exceeding 75 microM. Our data indicate that quercetin reduces cisplatin toxicity in cultured tubular epithelial cells. The exact mechanism of protection is unclear, though scavenging of free oxygen radicals may play an important role.

The glutamic acid derivative (S)-4-(3-18F-Fluoropropyl)-l-glutamic acid (18F-FSPG, alias BAY 94-9392), a new PET tracer for the detection of malignant diseases, displayed promising results in non–small cell lung cancer patients. The aim of this study was to provide dosimetry estimates for 18F-FSPG based on human whole-body PET/CT measurements. Methods:18F-FSPG was prepared by a fully automated 2-step procedure and purified by a solid-phase extraction method. PET/CT scans were obtained for 5 healthy volunteers (mean age, 59 y; age range, 51–64 y; 2 men, 3 women). Human subjects were imaged for up to 240 min using a PET/CT scanner after intravenous injection of 299 ± 22.5 MBq of 18F-FSPG. Image quantification, time–activity data modeling, estimation of normalized number of disintegrations, and production of dosimetry estimates were performed using the RADAR (RAdiation Dose Assessment Resource) method for internal dosimetry and in general concordance with the methodology and principles as presented in the MIRD 16 document. Results: Because of the renal excretion of the tracer, the absorbed dose was highest in the urinary bladder wall and kidneys, followed by the pancreas and uterus. The individual organ doses (mSv/MBq) were 0.40 ± 0.058 for the urinary bladder wall, 0.11 ± 0.011 for the kidneys, 0.077 ± 0.020 for the pancreas, and 0.030 ± 0.0034 for the uterus. The calculated effective dose was 0.032 ± 0.0034 mSv/MBq. Absorbed dose to the bladder and the effective dose can be reduced significantly by frequent bladder-voiding intervals. For a 0.75-h voiding interval, the bladder dose was reduced to 0.10 ± 0.012 mSv/MBq, and the effective dose was reduced to 0.015 ± 0.0010 mSv/MBq. Conclusion: On the basis of the distribution and biokinetic data, the determined radiation dose for 18F-FSPG was calculated to be 9.5 ± 1.0 mSv at a patient dose of 300 MBq, which is of similar magnitude to that of 18F-FDG (5.7 mSv). The effective dose can be reduced to 4.5 ± 0.30 mSv (at 300 MBq), with a bladder-voiding interval of 0.75 h.

Novel tracers for the diagnosis of malignant disease with PET and PET/CT are being developed as the most commonly used 18F deoxyglucose (FDG) tracer shows certain limitations. Employing radioactively labelled glutamate derivatives for specific imaging of the truncated citrate cycle potentially allows more specific tumour imaging. Radiation dosimetry of the novel tracer BAY 85-8050, a glutamate derivative, was calculated and the effective dose (ED) was compared with that of FDG. Five healthy volunteers were included in the study. Attenuation-corrected whole-body PET/CT scans were performed from 0 to 90 min, at 120 and at 240 min after injection of 305.0 ± 17.6 MBq of BAY 85-8050. Organs with moderate to high uptake at any of the imaging time points were used as source organs. Total activity in each organ at each time point was measured. Time–activity curves (TAC) were determined for the whole body and all source organs. The resulting TACs were fitted to exponential equations and accumulated activities were determined. OLINDA/EXM software was used to calculate individual organ doses and the whole-body ED from the acquired data. Uptake of the tracer was highest in the kidneys due to renal excretion of the tracer, followed by the pancreas, heart wall and osteogenic cells. The mean organ doses were: kidneys 38.4 ± 11.2 μSv/MBq, pancreas 23.2 ± 3.8 μSv/MBq, heart wall 17.4 ± 4.1 μSv/MBq, and osteogenic cells 13.6 ± 3.5 μSv/MBq. The calculated ED was 8.9 ± 1.5 μSv/MBq. Based on the distribution and dose estimates, the calculated radiation dose of BAY 85-8050 is 2.67 ± 0.45 mSv at a patient dose of 300 MBq, which compares favourably with the radiation dose of FDG (5.7 mSv).