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.

Background: Diabetic ketoacidosis (DKA) in children is associated with cerebrovascular-related complications. We recently reported that DKA facilitates leukocyte adherence to the brain microvascular endothelium. Adhered leukocytes can release enzymes that instigate vascular dysfunction. Our aims were to measure plasma levels of leukocyte-derived matrix metalloproteinases (MMPs) from DKA patients and to correlate plasma MMP concentrations with DKA severity. Methods: Plasma was obtained from children with type 1 diabetes, either in DKA (n = 16) or insulin controlled (CON; n = 16). Antibody microarray and gelatin zymography were used to quantify plasma MMPs and their endogenous tissue inhibitors (TIMPs). MMP concentrations were correlated with DKA severity (blood pH). Quantitative PCR of leukocyte mRNA was used to help determine the origin of plasma MMPs. results: DKA was associated with altered plasma levels of ↓MMP-2 (P < 0.001), ↑MMP-8 (P < 0.001), ↑MMP-9 (P < 0.05), and ↑TIMP-4 (P < 0.001), as compared with CON. Elevated MMP-8 and MMP-9 were both positively correlated with DKA severity (P < 0.05). DKA was associated with increased leukocyte mRNA for MMP-8, MMP-9, and TIMP-4 (P < 0.005). conclusion: MMPs are dynamically regulated during DKA. Plasma MMP-8 and MMP-9 concentrations correlate with DKA severity and are known to degrade brain microvascular endothelial cell tight junctions. Thus, leukocyte-derived MMPs might contribute to DKA-associated cerebrovascular complications.

BackgroundWe have demonstrated that carbon monoxide (CO)‐releasing molecules (CORMs) reduce septic inflammation by interfering with PMN recruitment to the inflamed organs. In this study, we assessed the effects/mechanisms of a newly synthesized Mn2+‐based water‐soluble CORM (CORM401) on PMN adhesion(A)/transendothelial migration(TM) in an experimental model of endotoxemia in vitro.MethodsHuman umbilical vein endothelial cells (HUVEC) grown on parallel flow channels were stimulated with LPS (1μg/ml; 6 hrs) and interacted with freshly isolated PMN (pretreated for 30 min with CORM401 or its inactive compound, iCORM401; 100μM) for 5 min in the presence of 1.0 dyn/cm2 shear stress. Subsequently, HUVEC:PMN co‐cultures were additionally perfused for 20 min with medium containing CORM/iCORM401. Video and confocal microscopy were used to analyze PMN A/TM.ResultsStimulation of HUVEC with LPS significantly increased PMN A (0.6+/‐0.1 vs 30.9+/‐7.6 cells/mm2; p<0.05) and TM (0.0 vs 41.7+/‐6.8%; p<0.001). Pretreatment of PMN with CORM401 had no effect on PMN A, however significantly reduced PMN TM (41.7+/‐6.8% vs 15.2+/‐4.3; p<0.01). The above findings were confirmed employing confocal microscopy.ConclusionCORM401 interferes with PMN recruitment by specific suppression of PMN migratory potential. (HSFO 393, IRF‐25‐12).