Particles of different sizes and shapes induce neutrophil necroptosis followed by the release of neutrophil extracellular trap-like chromatin

The human body is exposed to a wide range of particles of industrial, environmental or internal origin such as asbestos, alum, silica or crystals of urate, calcium phosphate, calcium oxalate, cystine or cholesterol. Phagocytic clearance of such particles involves neutrophils and macrophages. Here we report that neutrophils encountering such particles of diverse sizes and shapes undergo necrotic cell death, a process associated with the formation of neutrophil extracellular trap (NET)-like extracellular DNA. In human neutrophils receptor-interacting protein kinase (RIPK)-1 inhibition with necrostatin-1s or mixed lineage kinase domain-like (MLKL) inhibition with necrosulfonamide abrogated cell death and associated-neutrophil extracellular DNA release induced by all of the aforementioned particles. Similar results were obtained with Mlkl-deficient mice neutrophils for all particles in vitro. Furthermore, Mlkl-deficient mice lacked tophus formation upon injection of MSU crystals into subcutaneous air pouches. These findings imply that nano-or microparticle-induced neutrophil extracellular DNA release is the consequence of neutrophil necroptosis, a regulated form of cell necrosis defined by RIPK1-RIPK3-MLKL signaling. Interestingly, this finding was consistent across different particle sizes and shapes. The RIPK1-RIPK3-MLKL signaling pathway may represent a potential therapeutic target in nano-or microparticle-related diseases (crystallopathies)

Mitochondria Permeability Transition versus Necroptosis in Oxalate-Induced AKI

Serum oxalate levels suddenly increase with certain dietary exposures or ethylene glycol poisoning and are a well known cause of AKI. Established contributors to oxalate crystal-induced renal necroinflammation include the NACHT, LRR and PYD domains-containing protein-3 (NLRP3) inflammasome and mixed lineage kinase domain-like (MLKL) protein-dependent tubule necroptosis. These studies examined the role of a novel form of necrosis triggered by altered mitochondrial function. METHODS: To better understand the molecular pathophysiology of oxalate-induced AIK, we conducted in vitro studies in mouse and human kidney cells and in vivo studies in mice, including wild-type mice and knockout mice deficient in peptidylprolyl isomerase F (Ppif) or deficient in both Ppif and Mlkl. RESULTS: Crystals of calcium oxalate, monosodium urate, or calcium pyrophosphate dihydrate, as well as silica microparticles, triggered cell necrosis involving PPIF-dependent mitochondrial permeability transition. This process involves crystal phagocytosis, lysosomal cathepsin leakage, and increased release of reactive oxygen species. Mice with acute oxalosis displayed calcium oxalate crystals inside distal tubular epithelial cells associated with mitochondrial changes characteristic of mitochondrial permeability transition. Mice lacking Ppif or Mlkl or given an inhibitor of mitochondrial permeability transition displayed attenuated oxalate-induced AKI. Dual genetic deletion of Ppif and Mlkl or pharmaceutical inhibition of necroptosis was partially redundant, implying interlinked roles of these two pathways of regulated necrosis in acute oxalosis. Similarly, inhibition of mitochondrial permeability transition suppressed crystal-induced cell death in primary human tubular epithelial cells. PPIF and phosphorylated MLKL localized to injured tubules in diagnostic human kidney biopsies of oxalosis-related AKI. CONCLUSIONS: Mitochondrial permeability transition-related regulated necrosis and necroptosis both contribute to oxalate-induced AKI, identifying PPIF as a potential molecular target for renoprotective intervention.Peer reviewe

Does affordability affect mental health utilization? A United States-Israel comparison of older adults

The affordability of treatment is considered a major influence on the utilization of mental health services, a premise empirically examined in this research. Utilization patterns in the U.S. are compared with Israel, a country where access to treatment is not influenced by costs and their coverage. The focus is primarily on older adults, whose consistently low use of ambulatory services (in U.S.) has been attributed to financial barriers. The findings challenge the affordability-utilization assumption: (1) older Israeli ambulatory use is lower than in the U.S.; (2) Israeli elders have the lowest rates of all adult groups, the same pattern as in the U.S.; (3) older Israelis have a substantially higher inpatient rate than younger Israelis (mental health services costs and utilization ambulatory and inpatient age patterns policy implications

Prior hospitalization and age as predictors of mental health resource utilization in Israel

A two-part demand model based on data from a psychiatric case registry was estimated in order to search for predictors of hospital-based psychiatric care utilization. Using only age as an independent variable, explanation of future resource utilization is considerably weaker than when number of cumulative days of psychiatric hospital-based service use during the previous five years is also included. Only a small marginal gain is achieved by also adding diagnoses. Prospective remuneration by capitating sick funds according to age and past hospital-based service utilization records is recommended to avoid the twin pitfalls of cream-skimming and a distorted allocation of resources for psychiatric services.mental health utilization budgetary allocations