Nephrotoxicity and Kidney Transport Assessment on 3D Perfused Proximal Tubules

Proximal tubules in the kidney play a crucial role in reabsorbing and eliminating substrates from the body into the urine, leading to high local concentrations of xenobiotics. This makes the proximal tubule a major target for drug toxicity that needs to be evaluated during the drug development process. Here, we describe an advanced in vitro model consisting of fully polarized renal proximal tubular epithelial cells cultured in a microfluidic system. Up to 40 leak-tight tubules were cultured on this platform that provides access to the basolateral as well as the apical side of the epithelial cells. Exposure to the nephrotoxicant cisplatin caused a dose-dependent disruption of the epithelial barrier, a decrease in viability, an increase in effluent LDH activity, and changes in expression of tight-junction marker zona-occludence 1, actin, and DNA-damage marker H2A.X, as detected by immunostaining. Activity and inhibition of the efflux pumps P-glycoprotein (P-gp) and multidrug resistance protein (MRP) were demonstrated using fluorescence-based transporter assays. In addition, the transepithelial transport function from the basolateral to the apical side of the proximal tubule was studied. The apparent permeability of the fluorescent P-gp substrate rhodamine 123 was decreased by 35% by co-incubation with cyclosporin A. Furthermore, the activity of the glucose transporter SGLT2 was demonstrated using the fluorescent glucose analog 6-NBDG which was sensitive to inhibition by phlorizin. Our results demonstrate that we developed a functional 3D perfused proximal tubule model with advanced renal epithelial characteristics that can be used for drug screening studies.     

Severe Herpes Zoster Requiring Intravenous Antiviral Treatment in Allogeneic Hematopoietic Cell Transplantation Recipients on Standard Acyclovir Prophylaxis

Allogeneic hematopoietic cell transplantation (HCT) recipients are at increased risk for varicella zoster virus (VZV) reactivation and associated complications. The incidence, timing, and risk factors for severe herpes zoster (HZ) are not well described in the era of acyclovir (ACV) prophylaxis. We performed a retrospective cohort study of all patients who underwent first allogeneic HCT between October 2006 and December 2015 at our institution. Patients were followed until December 2017 for the development of severe HZ, defined as necessitating administration of i.v. antiviral medication. Out of 2163 patients who underwent allogeneic HCT, 22 (1.0%) developed severe HZ at a rate of 1 per 228 person-years, including dermatomal/multidermatomal disease (n = 5), disseminated skin disease (n = 5), HZ ophthalmicus (n = 4), meningitis/encephalitis (n = 4), pneumonia (n = 2), viremia (n = 1), and erythema multiforme (n = 1). Severe HZ infection occurred in a bimodal distribution during the early peri-HCT period and at 12 to 24 months post-HCT (median, 12.7 months). Twelve patients (54.5%) were compliant with ACV prophylaxis at the time of HZ diagnosis. Eleven patients (50%) died during the study period, only 2 of whom (9.1%) with active VZV infection. Mortality was higher in patients on immunosuppressive therapy (62.5% versus 16.7%; P = .045) and with concurrent graft-versus-host disease (75.0% versus 35.7%; P= .044). These data suggest that severe HZ remains an important consideration despite ACV prophylaxis.     

Risk Factors for Transplant-Associated Thrombotic Microangiopathy after Autologous Hematopoietic Cell Transplant in High-Risk Neuroblastoma

High-risk neuroblastoma has a poor prognosis, and research studies have shown that increasing the intensity of therapy improves outcomes. Autologous hematopoietic cell transplant (aHCT) as consolidation therapy confers a significant survival advantage but is accompanied by significant morbidity. Transplant-associated thrombotic microangiopathy (TA-TMA) is a life-threatening complication caused by endothelial injury that often leads to hemolytic anemia, microthrombotic platelet consumption, and renal injury. Here we investigated the incidence, potential risk factors, and sequelae of TA-TMA in patients with high-risk neuroblastoma. We conducted a retrospective chart review of all patients (n = 141) with neuroblastoma in our institutions who underwent aHCT from 2000 to 2017. Ten patients (7%) developed TA-TMA. The patients in the TA-TMA group were similar to the rest of the subjects in demographics, disease burden, prior therapies, renal function, and timing of transplant. The type of conditioning regimen was the only statistically significant pretransplant variable (P < .001). Six of 15 patients (40%) intended to receive tandem transplants (cyclophosphamide/thiotepa and then carboplatin/etoposide/melphalan (CEM)), 4 of 68 patients (6%) who received conditioning with single CEM, and none of the 56 patients who received busulfan/melphalan were diagnosed with TA-TMA. Patients with TA-TMA were more likely to require intensive care unit transfer, have a longer length of stay in the hospital, and experience a delay or change in their subsequent therapy. In our cohort overall, patients with a delay in therapy after transplant appeared to have a worse overall survival, although the difference was not statistically significant. Because of this high incidence and significant morbidity, we have implemented standardized screening for TA-TMA during and after transplant. We anticipate that screening will lead to earlier intervention and decreased severity of disease.     

Operational models and criteria for incorporating microbial whole genome sequencing in hospital microbiology – A systematic literature review

BackgroundMicrobial whole genome sequencing (WGS) has many advantages over standard microbiological methods. However, it is not yet widely implemented in routine hospital diagnostics due to notable challenges.ObjectivesThe aim was to extract managerial, financial and clinical criteria supporting the decision to implement WGS in routine diagnostic microbiology, across different operational models of implementation in the hospital setting.MethodsThis was a systematic review of literature identified through PubMed and Web of Science. English literature studies discussing the applications of microbial WGS without limitation on publication date were eligible. A narrative approach for categorization and synthesis of the sources identified was adopted.ResultsA total of 98 sources were included. Four main alternative operational models for incorporating WGS in clinical microbiology laboratories were identified: full in-house sequencing and analysis, full outsourcing of sequencing and analysis and two hybrid models combining in-house/outsourcing of the sequencing and analysis components. Six main criteria (and multiple related sub-criteria) for WGS implementation emerged from our review and included cost (e.g. the availability of resources for capital and operational investment); manpower (e.g. the ability to provide training programmes or recruit trained personnel), laboratory infrastructure (e.g. the availability of supplies and consumables or sequencing platforms), bioinformatics requirements (e.g. the availability of valid analysis tools); computational infrastructure (e.g. the availability of storage space or data safety arrangements); and quality control (e.g. the existence of standardized procedures).ConclusionsThe decision to incorporate WGS in routine diagnostics involves multiple, sometimes competing, criteria and sub-criteria. Mapping these criteria systematically is an essential stage in developing policies for adoption of this technology, e.g. using a multicriteria decision tool. Future research that will prioritize criteria and sub-criteria that were identified in our review in the context of operational models will inform decision-making at clinical and managerial levels with respect to effective implementation of WGS for routine use. Beyond WGS, similar decision-making challenges are expected with respect to future integration of clinical metagenomics.