Novel biomarkers and pathophysiology of membranous nephropathy: PLA2R and beyond.

Research on membranous nephropathy truly exploded in the last 15 years. This happened because of the application of new techniques (laser capture microdissection, mass spectrometry, protein G immunoprecipitation, arrays) to the study of its pathogenesis. After the discovery of PLA2R as the major target antigen, many other antigens were identified and others are probably ongoing. Clinical and pathophysiology rebounds of new discoveries are relevant in terms of diagnosis and prognosis and it is time to make a first assessment of the innovative issues. In terms of classification, target antigens can be divided into: 'membrane antigens' and 'second wave' antigens. The first group consists of antigens constitutionally expressed on the podocyte membrane (as PLA2R) that may become a target of an autoimmune process because of perturbation of immune-tolerance. 'Second wave' antigens are antigens neo-expressed by the podocyte or by infiltrating cells after a stressing event: this allows the immune system to produce antibodies against them that intensify and maintain glomerular damage. With this abundance of target antigens it is not possible, at the moment, to test all antibodies at the bedside. In the absence of this possibility, the role of histological evaluation is still irreplaceable.

Extracorporeal blood purification techniques in children with hyper-inflammatory syndromes: a clinical overview.

Data on clinical applications of blood purification techniques in children are scarce. The aim of this review is to offer a clinical overview, as complete as possible, on blood purification in children with hyper-inflammatory syndromes (HS). A review of the literature using the PubMed, EMBASE, Web of Science, and Scopus databases, on the most recent data about blood purification in children was conducted until June 2018. Except for three randomized controlled trials (RCTs) on plasma exchange, no RCTs, but only observational studies or case reports were found regarding other blood purification techniques in children. High-volume hemofiltration in two non-randomized trials did not significantly reduce 28-day mortality in children. PE was not associated with reduced mortality in pediatric patients with septic shock, but the small number of patients enrolled is an important limitation. The use of polymixin B and other adsorbing columns in children with septic shock and HS is increasing, but results are still limited by the observational nature of the studies. Based on the low-level of available evidence, no conclusions can be drawn regarding the efficacy and safety of blood purification in children. Further research with more clinically robust data is needed to determine the impact of different extracorporeal blood purification techniques in this pediatric population.

First experience on bilirubin removal with a hemoadsorption column (Lixelle®) in a child with cardiogenic liver injury.

INTRODUCTION: Hyperbilirubinemia may have deleterious effects on many organs, even after the neonatal age. Blood purification is effective in the treatment of hyperbilirubinemia. Recently some reports suggest the potential role of hemoadsorption columns in this setting. METHODS: We present the case of a 6-year-old child with severe hyperbilirubinemia due to congestive liver dysfunction, complicated by persistent inflammation, immunosuppression and catabolism syndrome (PICS). The patient was treated with a hemoadsorption column (Lixelle®) in combination with continuous veno-venous hemodiafiltration (CVVHDF). RESULTS: During treatment, a significant and rapid decrease in total bilirubin (TB) and other indices of cholestasis was observed. Furthermore, a progressive reduction in the inflammatory biomarkers (Procalcitonin, C-reactive protein) occurred. These results persisted at the discontinuation of therapy. CONCLUSIONS: To our knowledge this is the first case in which hemoadsorption with the Lixelle® adsorbing column in combination with CVVHDF has been used to manage pediatric hyperbiliribinemia secondary to cardiogenic liver injury.

Micromethod for quantification of cinacalcet in human plasma by liquid chromatography-tandem mass spectrometry using a stable isotope-labeled internal standard.

BACKGROUND: Cinacalcet hydrochloride is a calcimimetic agent indicated for the treatment of secondary hyperparathyroidism in dialysis-dependent patients with chronic kidney disease. In the context of a pharmacokinetic (PK)/pharmacodynamic study of cinacalcet in dialysis-dependent chronic kidney disease children with secondary hyperparathyroidism, we describe the development and validation of a new, rapid, simple, and economical liquid chromatography-tandem mass spectrometry (LC-MS/MS) micromethod for quantifying cinacalcet plasma concentrations. METHODS: Cinacalcet was analyzed in 50-µL plasma samples over a wide range of concentrations (0.1-100 ng/mL) by LC-MS/MS after protein precipitation and addition of deuterated cinacalcet as the internal standard. Cinacalcet was quantified using selective reaction monitoring of the specific transition m/z 358.1 > 155.1, with the 361.1 > 158.1 transition used for the internal standard. The suitability of the assay for clinical PK studies was evaluated using data from a pilot PK study in a pediatric patient. RESULTS: The overall turnaround time for the assay was 20 minutes. The lower limit of quantification of the method was 0.1 ng/mL. Intraassay imprecision and inaccuracy for quality control samples ranged from 2.8% to 9% and 100% to 102%, respectively. Interassay imprecision and inaccuracy ranged from 6.9% to 8.5% and 99% to 103%, respectively. The overall recovery ranged from 90% to 106%. No ion suppression due to matrix effects was found with different preanalytical conditions, such as hemolysis, lipemia, and hyperuricemia. CONCLUSIONS: This LC-MS/MS micromethod provides high specificity, precision, and accuracy for rapid quantification of cinacalcet plasma concentrations, and it is suitable for application in pediatric PK studies; it also has potential for use in the establishment of target ranges and ultimately routine therapeutic drug monitoring to optimize cinacalcet dosing.