The association of urinary epidermal growth factors with ADPKD disease severity and progression.

BACKGROUND: The epidermal growth factor receptor (EGFR) pathway is involved in kidney tissue repair and growth. Preclinical interventional data and scarce human data have suggested a role for this pathway in the pathophysiology of autosomal dominant polycystic kidney disease (ADPKD), while other data have suggested that its activation is causally linked to repair of damaged kidney tissue. We hypothesize that urinary EGFR ligands, as a reflection of EGFR activity, are associated with kidney function decline in ADPKD in the context of tissue repair following injury, and as the disease progresses as a sign of insufficient repair. METHODS: In the present study, we measured the EGFR ligands, EGF and heparin binding-EGF (HB-EGF), in 24-h urine samples of 301 ADPKD patients and 72 age- and sex-matched living kidney donors to dissect the role of the EGFR pathway in ADPKD. During a median follow-up of 2.5 years, the association of urinary EGFR ligand excretion with annual change in estimated glomerular filtration rate (eGFR) and height-adjusted total kidney volume in ADPKD patients was analyzed using mixed-models methods, and the expression of three closely related EGFR family receptors in ADPKD kidney tissue was investigated by immunohistochemistry. Additionally, the effect of reducing renal mass (after kidney donation), was assessed to investigate whether urinary EGF matches this reduction and thus reflects the amount of remaining healthy kidney tissue. RESULTS: At baseline, urinary HB-EGF did not differ between ADPKD patients and healthy controls (P = .6), whereas a lower urinary EGF excretion was observed in ADPKD patients [18.6 (11.8-27.8)] compared with healthy controls [51.0 (34.9-65.4) µg/24 h, P < .001]. Urinary EGF was positively associated with baseline eGFR (R = 0.54, P < .001) and a lower EGF was strongly associated with a more rapid GFR decline, even when adjusted for ADPKD severity markers (ß = 1.96, P < .001), whereas HB-EGF was not. Expression of the EGFR, but not other EGFR-related receptors, was observed in renal cysts but was absent in non-ADPKD kidney tissue. Finally, unilateral nephrectomy resulted in a decrease of 46.4 (-63.3 to -17.6) % in urinary EGF excretion, alongside a decrease of 35.2 ± 7.2% in eGFR and 36.8 ± 6.9% in measured GFR (mGFR), whereas maximal mGFR (measured after dopamine induced hyperperfusion) decreased by 46.1 ± 7.8% (all P < .001). CONCLUSIONS: Our data suggest that lower urinary EGF excretion may be a valuable novel predictor for kidney function decline in patients with ADPKD.

Development of an in vitro system and model-based translational framework to assess haemolysis risk following intravenous abuse of medications containing polyethylene oxide.

Multiple cases of potentially life-threatening thrombotic microangiopathy (TMA) have resulted from intravenous abuse of medications containing polyethylene oxide (PEO), most often Opana ER (oxymorphone hydrochloride extended release). No validated models are available to assess the risk of TMA with different formulations and extraction methods following intravenous abuse. We have developed an in vitro system that involves passing pooled blood containing the excipient of interest through a syringe needle and assessing haemolysis via haemoglobin release. Haemolysis is induced by high shear stress caused by the flow of blood containing PEO through a narrow-bore syringe needle, recapitulating the mechanism in small blood vessels. Using the in vitro system, we demonstrate that high-molecular-weight PEO (>1 MDa) induces haemolysis in a concentration-dependent manner under flowing but not static conditions. We use data from the in vitro system and published in vivo data to predict the time course of the haemolytic response in vivo via a pharmacometric model. The in vitro system is a novel method for investigating factors influencing PEO-induced haemolysis. In combination with our model-based translational framework, the in vitro system allows straightforward assessment of the haemolytic potential of PEO-containing medications, and may find application in gauging TMA risk following intravenous abuse.

Rapid Progression of Autosomal Dominant Polycystic Kidney Disease: Urinary Biomarkers as Predictors.

BACKGROUND: Markers currently used to predict the likelihood of rapid disease progression in patients with autosomal dominant polycystic kidney disease (ADPKD) are expensive and time consuming to assess and often have limited sensitivity. New, easy-to-measure markers are therefore needed that alone or in combination with conventional risk markers can predict the rate of disease progression. In the present study, we investigated the ability of tubular damage and inflammation markers to predict kidney function decline. METHODS: At baseline, albumin, immunoglobulin G, kidney injury molecule 1, ß2 microglobulin (ß2MG), heart-type fatty acid-binding protein, neutrophil gelatinase-associated lipocalin, and monocyte chemotactic protein-1 -(MCP-1) were measured in 24-h urine samples of patients participating in a study investigating the therapeutic efficacy of lanreotide in ADPKD. Individual change in estimated glomerular filtration rate (eGFR) during follow-up was calculated using mixed-model analysis taking into account 13 -eGFRs (chronic kidney disease EPIdemiology) per patient. Logistic regression analysis was used to select urinary biomarkers that had the best association with rapidly progressive disease. The predictive value of these selected urinary biomarkers was compared to other risk scores using C-statistics. RESULTS: Included were 302 patients of whom 53.3% were female, with an average age of 48 ± 7 years, eGFR of 52 ± 12 mL/min/1.73 m2, and a height-adjusted total kidney volume (htTKV) of 1,082 (736-1,669) mL/m. At baseline, all urinary damage and inflammation markers were associated with baseline eGFR, also after adjustment for age, sex and baseline htTKV. For longitudinal analyses only patients randomized to standard care were considered (n = 152). A stepwise backward analysis revealed that ß2MG and MCP-1 showed the strongest association with rapidly progressive disease. A urinary biomarker score was created by summing the ranking of tertiles of ß2MG and MCP-1 excretion. The predictive value of this urinary biomarker score was higher compared to that of the Mayo htTKV classification (area under the curve [AUC] 0.73 [0.64-0.82] vs. 0.61 [0.51-0.71], p = 0.04) and comparable to that of the predicting renal outcomes in -ADPKD score (AUC 0.73 [0.64-0.82] vs. 0.65 [0.55-0.75], p = 0.18). In a second independent cohort with better kidney function, similar results were found for the urinary biomarker score. CONCLUSION: Measurement of urinary ß2MG and MCP-1 excretion allows selection of ADPKD patients with rapidly progressive disease, with a predictive value comparable to or even higher than that of TKV or PKD mutation. Easy and inexpensive to measure urinary markers therefore hold promise to help predict prognosis in ADPKD.

Incidence of Massive Transfusion and Overall Transfusion Requirements During Lung Transplantation Over a 25-Year Period.

OBJECTIVE: To establish the incidence of massive transfusion and overall transfusion requirements during lung transplantation, changes over time, and association with outcome in relation to patient complexity. DESIGN: Retrospective cohort study. SETTING: University hospital. PARTICIPANTS: All 514 adult patients who underwent transplantation from 1990 until 2015. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patient records and transfusion data, divided into 5-year intervals, were analyzed. The incidence of massive transfusion (>10 units of red blood cells [RBCs] in 24 h) was 27% and did not change over time, whereas the median (interquartile range) transfusion requirement in the whole cohort decreased from 8 (5-12) to 3 (0-10) RBCs (p < 0.001). In patients transplanted from the intensive care unit, the incidence of massive transfusion increased over time from 25% to 54% (p = 0.04) and median transfusion requirements from 4.5 (3-8.5) units to 14.5 (5-26) units of RBCs (p = 0.03). Multivariable analysis showed that circulatory support, pulmonary hypertension, re-transplantation, cystic fibrosis, Eisenmenger syndrome, bilateral transplantation, and low body mass index were associated with massive transfusion. Patients with massive transfusion had more primary graft dysfunction grade III at 0, 24, 48, and 72 hours (p < 0.001), higher 30-day mortality (13% v 4%; p < 0.001), and lower 5-year survival (hazard ratio 3.67 [95% confidence interval 1.72-7.85]; p < 0.001). CONCLUSION: The incidence of massive transfusion did not change over time, whereas transfusion requirements in the whole cohort decreased. In patients transplanted from the intensive care unit, massive transfusion and transfusion requirements increased. Massive transfusion was associated with poor outcome.

Urinary Biomarkers to Identify Autosomal Dominant Polycystic Kidney Disease Patients With a High Likelihood of Disease Progression.

INTRODUCTION: The variable disease course of autosomal dominant polycystic kidney disease (ADPKD) makes it important to develop biomarkers that can predict disease progression, from a patient perspective and to select patients for renoprotective treatment. We therefore investigated whether easy-to-measure urinary biomarkers are associated with disease progression and have additional value over that of conventional risk markers. METHODS: At baseline, inflammatory, glomerular, and tubular damage markers were measured in 24-hour urine collections (albumin, IgG, kidney injury molecule-1 (KIM-1), N-acetyl-ß-d-glucosaminidase (NAG), ß2 microglobulin (ß2MG), heart-type fatty acid binding protein (HFABP), macrophage migration inhibitory factor (MIF), neutrophil gelatinase-associated lipocalin (NGAL), and monocyte chemotactic protein-1 (MCP-1). Disease progression was expressed as annual change in estimated glomerular filtration rate (eGFR, Chronic Kidney Disease EPIdemiology equation), measured glomerular filtation rate (mGFR, using 125I-iothalamate), or height-adjusted total kidney volume (htTKV). Multivariable linear regression was used to assess associations of these markers independent of conventional risk markers. RESULTS: A total of 104 ADPKD patients were included (40 ± 11 years, 39% female, eGFR 77 ± 30, mGFR 79 ± 30 ml/min per 1.73 m2 and htTKV 852 [510-1244] ml/m). In particular, ß2MG and MCP-1 were associated with annual change in eGFR, and remained associated after adjustment for conventional risk markers (standardized ß = -0.35, P = 0.001, and standardized ß = -0.29, P = 0.009, respectively). Adding ß2MG and MCP-1 to a model containing conventional risk markers that explained annual change in eGFR significantly increased the performance of the model (final R2  = 0.152 vs. 0.292, P = 0.001). Essentially similar results were obtained when only patients with an eGFR ≥ 60 ml/min per 1.73 m2 were selected, or when change in mGFR was studied. Associations with change in htTKV were less strong. CONCLUSION: Urinary ß2MG and MCP-1 excretion were both associated with GFR decline in ADPKD, and had added value beyond that of conventional risk markers. These markers therefore have the potential to serve as predictive tools for clinical practice.

Intraoperative cell salvage during cardiac surgery is associated with reduced postoperative lung injury.

OBJECTIVES: In addition to its blood-sparing effects, intraoperative cell salvage may reduce lung injury following cardiac surgery by removing cytokines, neutrophilic proteases and lipids that are present in cardiotomy suction blood. To test this hypothesis, we performed serial measurements of biomarkers of the integrity of the alveolar-capillary membrane, leucocyte activation and general inflammation. We assessed lung injury clinically by the duration of postoperative mechanical ventilation and the alveolar arterial oxygen gradient. METHODS: Serial measurements of systemic plasma concentrations of interleukin-6 (IL-6), myeloperoxidase, elastase, surfactant protein D (SP-D), Clara cell 16 kD protein (CC16) and soluble receptor for advanced glycation endproducts (sRAGEs) were performed on blood samples from 195 patients who underwent cardiac surgery with the use of a cell salvage (CS) device (CS, n = 99) or without (CONTROL, n = 96). RESULTS: Postoperative mechanical ventilation time was shorter in the CS group than in the CONTROL group [10 (8-15) vs 12 (9-18) h, respectively, P = 0.047]. The postoperative alveolar arterial oxygen gradient, however, was not different between groups. After surgery, the lung injury biomarkers CC16 and sRAGEs were lower in the CS group than in the CONTROL group. Biomarkers of systemic inflammation (IL-6, myeloperoxidase and elastase) were also lower in the CS group. Finally, mechanical ventilation time correlated with CC16 plasma concentrations. CONCLUSIONS: The intraoperative use of a cell salvage device resulted in less lung injury in patients after cardiac surgery as assessed by lower concentrations of lung injury markers and shorter mechanical ventilation times.

Urinary EGF Receptor Ligand Excretion in Patients with Autosomal Dominant Polycystic Kidney Disease and Response to Tolvaptan.

BACKGROUND AND OBJECTIVES: Recent animal experiments suggest that dysregulation of the EGF receptor pathway plays a role in the pathophysiology of autosomal dominant polycystic kidney disease (ADPKD). Research on EGF receptor ligands in humans with ADPKD is lacking. EGF receptor ligands were measured in patients with ADPKD at baseline and after treatment with a vasopressin V2 receptor antagonist (V2RA) because this information might provide a rationale for future V2RA combination therapy. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Blood and urine concentrations of the EGF receptor ligands heparin-binding (HB)-EGF, EGF, and TGF-α were measured by ELISAs in 27 patients with ADPKD who participated in a single-center study investigating a V2RA in 2011-2013 and in 27 controls who were selected from a general population-based observational study. Cyst fluid concentrations were also measured. In patients with ADPKD, ligands were measured at baseline, after 3-week treatment with a V2RA, and 3 weeks after drug withdrawal. The measured GFR (mGFR) was determined by iothalamate infusion, and total kidney volume was measured by magnetic resonance imaging. RESULTS: Urinary HB-EGF excretion and plasma concentration were higher in patients with ADPKD than in controls (median, 1.4 [interquartile range, 1.2-1.9] versus 0.6 [0.4-0.8] µg/24 hours [P<0.001] and 157.9 [83.1-225.9] versus 77.2 [37.2-174.3] pg/ml [P=0.04]). In contrast, urinary EGF excretion and plasma EGF concentration were lower in patients with ADPKD, whereas TGF-α did not differ between patients and controls. Higher HB-EGF excretion was correlated with more severe disease, assessed as lower mGFR (r=-0.39; P=0.05), higher total kidney volume (r=0.39; P=0.05), and higher urinary excretion of albumin and heart-type fatty acid-binding protein, whereas higher EGF excretion and TGF-α excretion were negatively correlated with disease severity. During V2RA treatment, HB-EGF excretion increased (from 1.4 [1.2-1.9] to 2.4 [2.1-3.1] µg/24 hours; P<0.001). CONCLUSION: In patients with ADPKD, higher urinary HB-EGF excretion is correlated with more severe disease. Whether this association is causal needs to be investigated in intervention studies.

Short-term Effects of Tolvaptan in Individuals With Autosomal Dominant Polycystic Kidney Disease at Various Levels of Kidney Function.

BACKGROUND: A recent study showed that tolvaptan, a vasopressin V2 receptor antagonist, decreased total kidney volume (TKV) growth and estimated glomerular filtration rate (GFR) loss in autosomal dominant polycystic kidney disease (ADPKD) with creatinine clearance≥60mL/min. The aim of our study was to determine whether the renal hemodynamic effects and pharmacodynamic efficacy of tolvaptan in ADPKD are dependent on GFR. STUDY DESIGN: Clinical trial with comparisons before and after treatment. SETTING & PARTICIPANTS: Patients with ADPKD with a wide range of measured GFRs (mGFRs; 18-148 mL/min) in a hospital setting. INTERVENTION: Participants were studied at baseline and after 3 weeks of treatment with tolvaptan given in increasing dosages, if tolerated (doses of 60, 90, and 120mg/d in weeks 1, 2, and 3, respectively). OUTCOMES: Change in markers for aquaresis (free-water clearance, urine and plasma osmolality, 24-hour urine volume, and plasma copeptin) and kidney injury (TKV and kidney injury biomarkers). MEASUREMENTS: GFR was measured by (125)I-iothalamate clearance; TKV, by magnetic resonance imaging; biomarker excretion, by enzyme-linked immunosorbent assay; and osmolality, by freezing point depression. RESULTS: In 27 participants (52% men; aged 46±10 years; mGFR, 69±39mL/min; TKV, 2.15 [IQR, 1.10-2.77] L), treatment with tolvaptan led to an increase in urine volume and free-water clearance and a decrease in urine osmolality, TKV, and kidney injury marker excretion. Changes in urine volume and osmolality with treatment were less in participants with lower baseline mGFRs (both P<0.01). However, change in fractional free-water clearance was greater at lower baseline mGFRs (P=0.001), suggesting that participants with decreased GFRs responded more to tolvaptan per functioning nephron. LIMITATIONS: Limited sample size, no control group. CONCLUSIONS: In patients with ADPKD with decreased kidney function, response to tolvaptan is lower for TKV, urinary volume, and osmolality, but larger for fractional free-water clearance. This latter finding suggests that patients with ADPKD with lower GFRs might benefit from long-term treatment with tolvaptan, as has been observed for patients with preserved GFRs.

The effect of pulsatile cardiopulmonary bypass on lung function in elderly patients.

PURPOSE: Cardiopulmonary bypass is still a major cause of lung injury and delay in pulmonary recovery after cardiac surgery. Although it has been shown that pulsatile flow induced by intra-aortic balloon pumping is beneficial for preserving lung function, it is not clear if the same beneficial effect can be accomplished with pulsatile flow generated in the extracorporeal circuit. Therefore, we investigated the effect of pulsatile flow, produced by a centrifugal pump, on lung function in elderly patients. METHODS: Serial measurements of lung biomarkers Clara cell 16 kD protein, surfactant protein D, and elastase were performed on blood samples from 37 elderly patients (≥75 years) who underwent elective aortic valve replacement surgery with CPB, either with pulsatile perfusion or continuous perfusion. Pulmonary function was assessed by postoperative ventilation time, the arterial blood oxygenation (PaO2/FiO2), the alveolar-arterial oxygen gradient (Aa-O2 gradient) and the pulmonary vascular resistance indexed by body surface area (PVRi). RESULTS: There was no difference in lung function between both groups, as assessed by the postoperative ventilation time, the PaO2/FiO2 ratio, and the Aa-O2 gradient. The PVRi, however, was significantly lower in the pulsatile perfusion group 15 mins after the administration of protamine (p<0.05). The plasma concentrations of the lung biomarkers increased during surgery and peaked at 1 h ICU, there were however no differences between groups. CONCLUSIONS: Pulsatile flow does not seem beneficial to postoperative lung function in elderly patients. Moreover, pulsatile flow does not affect lung function on a subclinical level as assessed by lung biomarkers.

Skin and plasma autofluorescence during hemodialysis: a pilot study.

Skin autofluorescence (AF) is related to the accumulation of advanced glycation end products (AGEs) and is one of the strongest prognostic markers of mortality in hemodialysis (HD) patients. The aim of this pilot study was to investigate whether changes in skin AF appear after a single HD session and if they might be related to changes in plasma AF. Skin and plasma AF were measured before and after HD in 35 patients on maintenance HD therapy (nine women and 26 men, median age 68 years, range 33-83). Median dialysis time was 4 h (range 3-5.5). Skin AF was measured noninvasively with an AGE Reader, and plasma AF was measured before and after HD at 460 nm after excitation at 370 nm. The HD patients had on average a 65% higher skin AF value than age-matched healthy persons (P < 0.001). Plasma AF was reduced by 14% (P < 0.001), whereas skin AF was not changed after a single HD treatment. No significant influence of the reduced plasma AF on skin AF levels was found. This suggests that the measurement of skin AF can be performed during the whole dialysis period and is not directly influenced by the changes in plasma AF during HD.

In situ lung perfusion is a valuable tool to assess lungs from donation after circulatory death donors category I-II.

Donations after circulatory death (DCD) lung grafts are an alternative to extend the donor pool in lung transplantation. This study investigates the use of an in situ lung perfusion system (ISLP) in the donor to evaluate category I-II lungs. Pigs were sacrificed by ventricular fibrillation. All animals underwent 20 min of cardiopulmonary resuscitation and 5 min hands-off period after which heparin was administered. In group [WI-1], this was followed by 1 h of warm ischemia (WI) and 2 h of topical cooling (TC). In group [WI-2], 2 h of WI was followed by 1 h of TC. In group [WI-0], there was a minimal period of WI and no TC. In all three groups, the lungs were then evaluated during 60 min with ISLP. [WI-0] lungs showed a significantly higher compliance and Δ PO2 /FiO2 compared with [WI-1] and [WI-2]. PaCO2 and lactate production were higher in [WI-2] versus [WI-0]. Wet/Dry weight ratio was significantly higher in [WI-2] compared with [WI-0] in two lung biopsy locations. A high W/D weight ratio was correlated with a lower compliance, higher lactate production, and a higher PaCO2 . ISLP is an effective way to assess the quality of lungs from category I-II DCD donors.

The utility of lung epithelium specific biomarkers in cardiac surgery: a comparison of biomarker profiles in on- and off-pump coronary bypass surgery.

BACKGROUND: Despite continuous improvements in materials and perfusion techniques, cardiac surgery still causes lung injury and a delay of pulmonary recovery. Currently, there is no gold standard for quantifying cardiac surgery induced lung injury and dysfunction. Adding objective measures, such as plasma biomarkers, could be of great use here. In this study the utility of lung epithelium specific proteins as biomarkers for lung dysfunction was evaluated. METHODS: Serial measurements of plasma concentrations of Clara cell 16 kD (CC16) protein, Surfactant protein D (SP-D), Elastase and Myeloperoxidase were performed on blood samples from 40 patients who underwent coronary artery bypass grafting with cardiopulmonary bypass (CABG, n = 20) or without cardiopulmonary bypass (OPCAB, n = 20). RESULTS: The increase of SP-D and CC16 between pre-operative concentrations and concentrations at the end of cardiopulmonary bypass, correlated with the Aa-O2 gradient at 1 hour on the ICU (Rs = 0.409, p = .016 and Rs = 0.343, p = .043, respectively).Furthermore, SP-D and CC16 were higher in CABG than in OPCAB at the end of surgery [8.96 vs. 4.91 ng/mL, p = .042 and 92 vs. 113%, p = .007, respectively]. After 24 h both biomarkers returned to their baseline values. CONCLUSIONS: Our results show that increases in plasma of SP-D and CC16 correlate with clinical lung injury after coronary artery bypass surgery. Therefore, lung epithelium specific proteins seem to be a useful biomarker for measuring lung injury in the setting of cardiac surgery.

Polyacylurethanes as Novel Degradable Cell Carrier Materials for Tissue Engineering.

Polycaprolactone (PCL) polyester and segmented aliphatic polyester urethanes based on PCL soft segment have been thoroughly investigated as biodegradable scaffolds for tissue engineering. Although proven beneficial as long term implants, these materials degrade very slowly and are therefore not suitable in applications in which scaffold support is needed for a shorter time. A recently developed class of polyacylurethanes (PAUs) is expected to fulfill such requirements. Our aim was to assess in vitro the degradation of PAUs and evaluate their suitability as temporary scaffold materials to support soft tissue repair. With both a mass loss of 2.5-3.0% and a decrease in molar mass of approx. 35% over a period of 80 days, PAUs were shown to degrade via both bulk and surface erosion mechanisms. Fourier Transform Infra Red (FTIR) spectroscopy was successfully applied to study the extent of PAUs microphase separation during in vitro degradation. The microphase separated morphology of PAU1000 (molar mass of the oligocaprolactone soft segment = 1000 g/mol) provided this polymer with mechano-physical characteristics that would render it a suitable material for constructs and devices. PAU1000 exhibited excellent haemocompatibility in vitro. In addition, PAU1000 supported both adhesion and proliferation of vascular endothelial cells and this could be further enhanced by pre-coating of PAU1000 with fibronectin (Fn). The contact angle of PAU1000 decreased both with in vitro degradation and by incubation in biological fluids. In endothelial cell culture medium the contact angle reached 60°, which is optimal for cell adhesion. Taken together, these results support the application of PAU1000 in the field of soft tissue repair as a temporary degradable scaffold.