Biologia e genetica del podocita

Progresses in podocyte biology have been strictly connected with genetic advances; the identification of genes mutated in familial and sporadic forms of nephrotic syndrome has been followed by functional studies of the encoded proteins, revealing numerous properties of the cell. The molecules uncovered so far belong to three main categories: a) proteins located at the slit diaphragm, the intercellular junction which laterally connects podocyte processes and is responsible for selectivity of the glomerular filter, b) molecules involved in regulation of actin dynamics, which are essential for the maintenance of podocyte structure and function, and c) molecules belonging to intracellular organelles, such as mitochondria and lysosomes, which are central players in podocyte metabolism. Considering the key role of the podocyte in health and disease of the glomerular filter, better knowledge of this cell is a pre-requisite for developing targeted therapies of glomerular diseases

Three-dimensional podocyte-endothelial cell co-cultures: Assembly, validation, and application to drug testing and intercellular signaling studies

15noProteinuria is a common symptom of glomerular diseases and is due to leakage of proteins from the glomerular filtration barrier, a three-layer structure composed by two post-mitotic highly specialized and interdependent cell populations, i.e. glomerular endothelial cells and podocytes, and the basement membrane in between. Despite enormous progresses made in the last years, pathogenesis of proteinuria remains to be completely uncovered. Studies in the field could largely benefit from an in vitro model of the glomerular filter, but such a system has proved difficult to realize. Here we describe a method to obtain and utilize a three-dimensional podocyte-endothelial co-culture which can be largely adopted by the scientific community because it does not rely on special instruments nor on the synthesis of devoted biomaterials. The device is composed by a porous membrane coated on both sides with type IV collagen. Adhesion of podocytes on the upper side of the membrane has to be preceded by VEGF-induced maturation of endothelial cells on the lower side. The co-culture can be assembled with podocyte cell lines as well as with primary podocytes, extending the use to cells derived from transgenic mice. An albumin permeability assay has been extensively validated and applied as functional readout, enabling rapid drug testing. Additionally, the bottom of the well can be populated with a third cell type, which multiplies the possibilities of analyzing more complex glomerular intercellular signaling events. In conclusion, the ease of assembly and versatility of use are the major advantages of this three-dimensional model of the glomerular filtration barrier over existing methods. The possibility to run a functional test that reliably measures albumin permeability makes the device a valid companion in several research applications ranging from drug screening to intercellular signaling studies.reservedmixedLi, Min; Corbelli, Alessandro; Watanabe, Shojiro; Armelloni, Silvia; Ikehata, Masami; Parazzi, Valentina; Pignatari, Chiara; Giardino, Laura; Mattinzoli, Deborah; Lazzari, Lorenza; Puliti, Aldamaria; Cellesi, Francesco; Zennaro, Cristina; Messa, Piergiorgio; Rastaldi, Maria PiaLi, Min; Corbelli, Alessandro; Watanabe, Shojiro; Armelloni, Silvia; Ikehata, Masami; Parazzi, Valentina; Pignatari, Chiara; Giardino, Laura; Mattinzoli, Deborah; Lazzari, Lorenza; Puliti, Aldamaria; Cellesi, Francesco; Zennaro, Cristina; Messa, Piergiorgio; Rastaldi, Maria Pi

Use of the WHO Access, Watch, and Reserve classification to define patterns of hospital antibiotic use (AWaRe) : an analysis of paediatric survey data from 56 countries

Background Improving the quality of hospital antibiotic use is a major goal of WHO's global action plan to combat antimicrobial resistance. The WHO Essential Medicines List Access, Watch, and Reserve (AWaRe) classification could facilitate simple stewardship interventions that are widely applicable globally. We aimed to present data on patterns of paediatric AWaRe antibiotic use that could be used for local and national stewardship interventions. Methods 1-day point prevalence survey antibiotic prescription data were combined from two independent global networks: the Global Antimicrobial Resistance, Prescribing, and Efficacy in Neonates and Children and the Global Point Prevalence Survey on Antimicrobial Consumption and Resistance networks. We included hospital inpatients aged younger than 19 years receiving at least one antibiotic on the day of the survey. The WHO AWaRe classification was used to describe overall antibiotic use as assessed by the variation between use of Access, Watch, and Reserve antibiotics, for neonates and children and for the commonest clinical indications. Findings Of the 23 572 patients included from 56 countries, 18305 were children (77.7%) and 5267 were neonates (22.3%). Access antibiotic use in children ranged from 7.8% (China) to 61.2% (Slovenia) of all antibiotic prescriptions. The use of Watch antibiotics in children was highest in Iran (77.3%) and lowest in Finland (23.0%). In neonates, Access antibiotic use was highest in Singapore (100.0%) and lowest in China (24.2%). Reserve antibiotic use was low in all countries. Major differences in clinical syndrome-specific patterns of AWaRe antibiotic use in lower respiratory tract infection and neonatal sepsis were observed between WHO regions and countries. Interpretation There is substantial global variation in the proportion of AWaRe antibiotics used in hospitalised neonates and children. The AWaRe classification could potentially be used as a simple traffic light metric of appropriate antibiotic use. Future efforts should focus on developing and evaluating paediatric antibiotic stewardship programmes on the basis of the AWaRe index. Copyright (C) 2019 The Author(s). Published by Elsevier Ltd