Human vascularized bile duct-on-a chip: a multi-cellular micro-physiological system for studying cholestatic liver disease.

Exploring the pathogenesis of and developing therapies for cholestatic liver diseases such as primary sclerosing cholangitis (PSC) remains challenging, partly due to a paucity ofin vitromodels that capture the complex environments contributing to disease progression and partly due to difficulty in obtaining cholangiocytes. Here we report the development of a human vascularized bile duct-on-a-chip (VBDOC) that uses cholangiocyte organoids derived from normal bile duct tissue and human vascular endothelial cells to model bile ducts and blood vessels structurally and functionally in three dimensions. Cholangiocytes in the duct polarized, formed mature tight junctions and had permeability properties comparable to those measured inex vivosystems. The flow of blood and bile was modeled by perfusion of the cell-lined channels, and cholangiocytes and endothelial cells displayed differential responses to flow. We also showed that the device can be constructed with biliary organoids from cells isolated from both bile duct tissue and the bile of PSC patients. Cholangiocytes in the duct became more inflammatory under the stimulation of IL-17A, which induced peripheral blood mononuclear cells and differentiated Th17 cells to transmigrate across the vascular channel. In sum, this human VBDOC recapitulated the vascular-biliary interface structurally and functionally and represents a novel multicellular platform to study inflammatory and fibrotic cholestatic liver diseases.

Steroid therapy may be effective in augmenting hemoglobin levels during hemolytic crises in children with hereditary spherocytosis.

BACKGROUND: The course of hereditary spherocytosis (HS) may be subject to hemolytic episodes, sometimes requiring blood transfusion. The aim of this study was to evaluate the efficacy of a short course of steroid therapy in elevating hemoglobin levels during hemolytic crisis. PROCEDURE: The files of all patients followed for HS from 1968 to 2009 at our hospital were reviewed. Outcome of hemolytic crises was compared between steroid-treated and untreated patients; patients given packed red blood cell transfusion(s) or erythropoietin treatment were excluded. A good outcome was defined as an increase of at least 20% in hemoglobin level from the nadir within 1 week. RESULTS: Of the 118 patients with HS who attended our hospital during the study period, 20 were treated with steroids and 9 received no treatment. Mean nadir hemoglobin level in both groups was 6.9 g/dl. The study group had a total of 50 steroid-treated hemolytic crises of which 37 (74%) responded favorably to treatment. Treatment failure was significantly associated with a low dose (<1 mg/kg/day) or short duration (<1 week) of treatment. The nine untreated patients had 16 hemolytic crises, of which 25% had a good outcome. Steroid therapy was significantly more effective than no therapy in increasing hemoglobin level (P = 0.015) in these hemolytic crises. CONCLUSION: Steroid therapy may be effective in augmenting hemoglobin levels during hemolytic crises in patients with moderate HS and eventually will result in a reduced need for RBC transfusion.

Clinical Outcomes and Antibody Response in COVID-19-Positive Pediatric Solid Organ Transplant Recipients.

We describe the clinical and laboratory manifestations and outcomes of 25 pediatric solid organ transplant recipients who tested positive for severe acute respiratory coronavirus-2. Twenty-one (84%) developed a mild disease; 22 of 23 (96%) had a positive serologic response. Two patients (8%), both kidney transplant recipients with additional comorbidities, developed a severe disease. The findings emphasize the need for close monitoring of this population.

[Nontuberculous mycobacterial lymphadenitis with an emerging pathogen and a novel management approach].

Nontuberculous mycobacterial infections in immunocompetent children usually presents as chronic lymphadenitis involving the neck and face. Mycobacterium avium complex is the most common pathogen, although recent series found Mycobacterium haemophilum, to be a major cause of chronic lymphadenitis in otherwise healthy children. The authors describe a 9-month-old baby who presented with a 4-month history of preauricular lymphadenitis. Mycobacterial culture yielded Mycobacterium haemophilum. A no-intervention approach was chosen. At the 6-month follow-up, the swelling had ameliorated and the skin showed a small scar with near-normal overlying skin color. A literature review of the clinical manifestations and diagnosis of Mycobacterium haemophilum lymphadenitis and of the different management options for nontuberculous mycobacterial lymphadenitis in otherwise healthy children is presented.