F2-isoprostanes affect macrophage migration and CSF-1 signalling.

F2-isoprostanes (F2-IsoP) are formed in vivo via free radical peroxidation of arachidonic acid. Enhanced oxidative stress is implicated in the development of atherosclerosis in humans and F2-IsoP have been detected in atherosclerotic plaque. Colony stimulating factor-1 (CSF-1) is essential to macrophage survival, proliferation and differentiation and has been detected in human atherosclerotic plaques. Accumulation of macrophages within the vascular wall is an important component of atherosclerosis but little is known about the effect of F2-IsoP on the migration of these cells. Our aim was to examine the effect of free and lipid-bound 15-F2t-isoprostane (15-F2t-IsoP) on macrophage migration and investigate the signalling pathways involved. Mouse macrophages (cell line BAC1.2F5) were pre-incubated with 15-F2t-IsoP (free, bound to cholesterol or monoacylglycerol or within oxidized phospholipid) and cell migration was assessed using chemotaxis towards CSF-1 in Boyden chambers. Migration was also measured using the wound healing assay with primary mouse bone marrow derived macrophages. We showed that 15-F2t-IsoP dose-dependently inhibited BAC1.2F5 macrophage spreading and adhesion but stimulated their migration towards CSF-1, with maximum effect at 10 µM. Analysis of CSF-1 stimulated signalling pathways in BAC1.2F5 macrophages showed that phosphorylation of Akt, a key mediator of cell migration, and one of its regulators, the mTORC2 component, Rictor, was significantly decreased. In contrast, phosphorylation of the adhesion kinases, FAK and Pyk2, and the adhesion scaffold protein, paxillin, was enhanced after treatment with 15-F2t-IsoP. Mouse bone marrow macrophages were transfected with FAK or Pyk2 small interfering RNA (siRNA) to examine the role of FAK and Pyk2 in 15-F2t-IsoP signalling. Pyk2 silencing inhibited 15-F2t-IsoP-induced reduction in cell area and phospho-paxillin adhesion numbers. The size distribution of adhesions in the presence of 15-F2t-IsoP was also affected by Pyk2 silencing and there was a trend for Pyk2 silencing to reduce 15-F2t-IsoP-stimulated macrophage migration. These results demonstrate that 15-F2t-IsoP affects macrophage adhesions and migration, which are integral components of macrophage involvement in atherosclerosis.

Intraoperative cardiovascular collapse secondary to latex allergy.

An apparent allergic reaction has been noted in children undergoing open urological surgery. This condition is characterized by precipitous hypotension, tachycardia and upper body flushing, and it often causes termination of the procedure. Latex allergy has been identified as the possible inciting event. Contact of latex rubber gloves with intra-abdominal structures (handling bowel) appears to be the most dramatic trigger mechanism for this reaction. We report on 10 patients with latex allergy, 6 of whom have myelomeningocele, who have undergone reconstructive surgery. Severe anaphylactic shock developed intraoperatively in 5 patients and during a barium enema performed with a latex catheter in 1 patient. These 6 patients had previous allergic reactions to latex material, which was not detected preoperatively. In the remaining 4 patients latex allergy was diagnosed preoperatively. A total of 6 patients agreed to a skin prick test to liquid latex. Three patients reacted with a wheal size greater than or equal to a histamine control at a dilution of 1:1,000 and 3 patients at 1:100. In contrast, none of the 5 normal controls reacted to any of the concentrations including full strength latex. A history of exposure to latex products (balloons, surgical gloves, catheters, condoms and so forth) with allergic reactions should heighten surgeon awareness of a potentially severe intraoperative reaction. Furthermore, a skin prick test may be used to screen high risk patients such as those with myelomeningocele. A protocol involving preoperative corticosteroid and antihistamine therapy is recommended.