cathepsin-g and Brain-Edema

Diabetic ketoacidosis in children is associated with vasogenic cerebral edema, possibly due to the release of destructive polymorphonuclear neutrophil azurophilic enzymes. Our objectives were to measure plasma azurophilic enzyme levels in children with diabetic ketoacidosis, to correlate plasma azurophilic enzyme levels with diabetic ketoacidosis severity, and to determine whether azurophilic enzymes disrupt the blood-brain barrier in vitro.. Prospective clinical and laboratory study.. The Children's Hospital, London Health Sciences Centre.. Pediatric type 1 diabetes patients; acute diabetic ketoacidosis or age-/sex-matched insulin-controlled.. Acute diabetic ketoacidosis in children was associated with elevated polymorphonuclear neutrophils. Plasma azurophilic enzymes were elevated in diabetic ketoacidosis patients, including human leukocyte elastase (p < 0.001), proteinase-3 (p < 0.01), and myeloperoxidase (p < 0.001). A leukocyte origin of human leukocyte elastase and proteinase-3 in diabetic ketoacidosis was confirmed with buffy coat quantitative real-time polymerase chain reaction (p < 0.01). Of the three azurophilic enzymes elevated, only proteinase-3 levels correlated with diabetic ketoacidosis severity (p = 0.002). Recombinant proteinase-3 applied to human brain microvascular endothelial cells degraded both the tight junction protein occludin (p < 0.05) and the adherens junction protein VE-cadherin (p < 0.05). Permeability of human brain microvascular endothelial cell monolayers was increased by recombinant proteinase-3 application (p = 0.010).. Our results indicate that diabetic ketoacidosis is associated with systemic polymorphonuclear neutrophil activation and degranulation. Of all the polymorphonuclear neutrophil azurophilic enzymes examined, only proteinase-3 correlated with diabetic ketoacidosis severity and potently degraded the blood-brain barrier in vitro. Proteinase-3 might mediate vasogenic edema during diabetic ketoacidosis, and selective proteinase-3 antagonists may offer future vascular- and neuroprotection.

Topics: Blood-Brain Barrier; Brain Edema; Case-Control Studies; Cathepsin G; Cell Culture Techniques; Child; Diabetes Mellitus, Type 1; Diabetic Ketoacidosis; Endothelial Cells; Female; Humans; Leukocyte Elastase; Male; Myeloblastin; Peroxidase

Previous studies have indicated that thrombin (TM) may play a major role in brain edema after intracerebral hemorrhages (ICHs). However, the mechanism of TM-induced brain edema is poorly understood. In this study, we explored the effect of TM on the permeability of the blood brain barrier (BBB) and investigated its possible mechanism, aiming at providing a potential target for brain edema therapy after ICHs.. TM or TM + cathepsin G (CATG) was stereotaxically injected into the right caudate nucleus of Sprague-Dawley rats in vivo. BBB permeability was measured by Evans-Blue extravasation. Brain water content was determined by the dry-wet weight method. Brain microvascular endothelial cells were then cultured in vitro. After TM or TM + CATG was added to the endothelial cell medium, changes in the morphology of cells were dynamically observed by phase-contrast light microscopy, and the expression of matrix metalloproteinase-2 (MMP-2) protein was measured by immunohistochemical method.. BBB permeability increased at 6 hours after a TM injection into the ipsilateral caudate nucleus (P < 0.05), peaked between 24 hours (P < 0.01) and 48 hours (P < 0.05) after the injection, and then declined. Brain water content changed in parallel with the changes in BBB permeability. However, at all time points, BBB permeability and brain water content after a TM + CATG injection were not significantly different from the respective parameters in the control group (P > 0.05). TM induced endothelial cell contraction in vitro in a time-dependent manner and enhanced the expression of MMP-2 protein. After incubation with TM + CATG, cell morphology and MMP-2 expression did not change significantly as compared to the control group (P > 0.05).. Increased BBB permeability may be one of the mechanisms behind TM-induced cerebral edema. TM induces endothelial cell contraction and promotes MMP-2 expression by activating protease activated receptor-1 (PAR-1), possibly leading to the opening of the BBB.

Topics: Animals; Blood-Brain Barrier; Body Water; Brain Edema; Cathepsin G; Cathepsins; Cerebral Hemorrhage; Matrix Metalloproteinase 2; Permeability; Rats; Rats, Sprague-Dawley; Receptor, PAR-1; Serine Endopeptidases; Thrombin