Leukocyte antibacterial functions are not impaired by perfluorocarbon exposure in vitro

Cytosolic perfluorocarbon delivery to platelets via albumin for antithrombotic therapy

Thrombosis is a major contributor to global disease burden. Antiplatelet therapy is the critical approach to prevent thrombosis by reducing platelet reactivity. However, classical antiplatelet strategies generally interfere with platelet integrin α_IIbβ₃-mediated platelet activation, thereby facing severe bleeding risk. To break the limitation, we described an integrin α_IIbβ₃-independent antiplatelet method by cytosolic delivery of nanoscale perfluorocarbon (PFC) to platelets via albumin carrier. Denatured albumin was found to build high affinity with platelets to mediate cytosolic PFC delivery. While, cytosolic PFC impaired cytoskeleton reorganization during platelet activation to inhibit relevant platelet functions, but avoided to interfere with integrin α_IIbβ₃. We proved that this α_IIbβ₃-indenpendent antiplatelet pattern showed potential antiplatelet effect with low bleeding risk to prevent thrombosis in various thrombosis models. Together, cytosolic PFC delivery via albumin is a promising antiplatelet approach, and will provide an alternative regimen for current antithrombotic therapy.

Platelet and White Cell Reactivity to Top-Load Intravenous Perfluorocarbon Infusion in Healthy Sheep

BACKGROUND

Perfluorocarbon emulsions (PFCs) are intravenous artificial oxygen carriers with enhanced gas solubility. As lipid micelle nanoparticle emulsions, PFCs may have a class effect that causes degrees of thrombocytopenia. Understanding the extent of the platelet effects, including mechanism and potential inflammation after PFC infusion, is important for safe human trials.

METHODS

Normal sheep (Dorper) were infused with 5 mL/kg of Oxygent (w/v 60% PFC) or Perftoran (w/v 20% PFC). Controls received 6% Hetastarch or were naive. Blood samples were analyzed from baseline, time 0 (the end of infusion), 3 and 24 hours, and 4 and 7 days. Platelet count, plateletcrit, mean platelet volume, platelet distribution width, and CD-62p (a platelet activation-dependent membrane protein) were measured. Neutrophils, monocytes, and total white blood cell counts were analyzed.

RESULTS

In these inflammatory cell lines, there were no consistent changes or cellular activation after PFC infusion. A decrease (<10% from baseline and naive controls) in platelet count was seen on day 4 after Oxygent infusion (3 g/kg), which recovered by day 7. No platelet effect was seen in Perftoran (1 g/kg). Plateletcrit, mean platelet volume, and platelet distribution width did not change significantly at any time point among the groups. CD-62p, ADP, and collagen aggregometry showed no significant change in platelet function.

CONCLUSION

There was no evidence of overall reduction in platelet number, or any correlation with the change in platelet activation or inhibition. Therefore, the risk of increased thrombosis/bleeding after PFC intravenous infusion is low in this non-trauma sheep model.

Systemic administration of FC-77 dampens ischemia-reperfusion-induced acute lung injury in rats

Systemic administration of perfluorocarbons (PFCs) reportedly attenuates acute lung injury induced by acid aspiration and phorbol myristate acetate. However, the effects of PFCs on ischemia–reperfusion (IR)-induced lung injury have not been investigated. Typical acute lung injury was induced in rats by 60 min of ischemia and 60 min of reperfusion in isolated and perfused rat lung model. Rat lungs were randomly assigned to receive PBS (control), 1 % FC-77, IR only, or IR with different doses of FC-77 (0.1 %, 0.5 %, or 1 %). Subsequently, bronchoalveolar lavage fluid (BALF), perfusate, and lung tissues were collected to evaluate the degree of lung injury. IR caused a significant increase in the following parameters: pulmonary arterial pressure, capillary filtration coefficient, lung weight gain, lung weight/body weight ratio, wet/dry lung weight ratio, and protein concentration in BALF. TNF-α and cytokine-induced neutrophil chemoattractant-1 concentrations in perfusate samples and MDA concentration and MPO activities in lung tissues were also significantly increased. Histopathology showed increased septal thickness and neutrophil infiltration in the lung tissues. Furthermore, NF-κB activity was significantly increased in the lungs. However, pretreatment with 1 % FC-77 prior to IR significantly attenuated the increases in these parameters. In conclusion, our results suggest that systemic FC-77 administration had a protective effect on IR-induced acute lung injury. These protective mechanisms may have been mediated by the inhibition of NF-κB activation and attenuation of subsequent inflammatory response.

Selective in vivo visualization of immune-cell infiltration in a mouse model of autoimmune myocarditis by fluorine-19 cardiac magnetic resonance

BACKGROUND

The goal of this study was to characterize the performance of fluorine-19 ((19)F) cardiac magnetic resonance (CMR) for the specific detection of inflammatory cells in a mouse model of myocarditis. Intravenously administered perfluorocarbons are taken up by infiltrating inflammatory cells and can be detected by (19)F-CMR. (19)F-labeled cells should, therefore, generate an exclusive signal at the inflamed regions within the myocardium.

METHODS AND RESULTS

Experimental autoimmune myocarditis was induced in BALB/c mice. After intravenous injection of 2×200 µL of a perfluorocarbon on day 19 and 20 (n=9) after immunization, in vivo (19)F-CMR was performed at the peak of myocardial inflammation (day 21). In 5 additional animals, perfluorocarbon combined with FITC (fluorescein isothiocyanate) was administered for postmortem immunofluorescence and flow-cytometry analyses. Control experiments were performed in 9 animals. In vivo (19)F-CMR detected myocardial inflammation in all experimental autoimmune myocarditis-positive animals. Its resolution was sufficient to identify even small inflammatory foci, that is, at the surface of the right ventricle. Postmortem immunohistochemistry and flow cytometry confirmed the presence of perfluorocarbon in macrophages, dendritic cells, and granulocytes, but not in lymphocytes. The myocardial volume of elevated (19)F signal (rs=0.96; P<0.001), the (19)F signal-to-noise ratio (rs=0.92; P<0.001), and the (19)F signal integral (rs=0.96; P<0.001) at day 21 correlated with the histological myocarditis severity score.

CONCLUSIONS

In vivo (19)F-CMR was successfully used to visualize the inflammation specifically and robustly in experimental autoimmune myocarditis, and thus allowed for an unprecedented insight into the involvement of inflammatory cells in the disease process.

Increased percentage of B cells in patients with more advanced hepatocellular carcinoma

To compare immunologic phenotypes between (1) hepatocellular carcinoma (HCC) patients and a healthy population and (2) more advanced and early stage HCC patients, we studied 45 HCC patients and 46 healthy controls from January 2006 to January 2008. Using fluorescent activated cell sorter (FACS) analysis, HCC patients were demonstrated to exhibit stronger phagocytosis of granulocytes and monocytes and more peripheral blood mononuclear cells (PBMCs) in the G2/M phase compared with healthy volunteers. By contrast, lower percentages of B and T(h) lymphocytes were also found in the peripheral blood of HCC patients than in the healthy population. Most importantly, a higher percentage of B cells was found in patients with advanced HCC than in those with early HCC in terms of TNM stage (II and III vs I, p = 0.004), the Japanese Integrated Scoring system (2-3 vs 0-1, p = 0.0235), and tumor numbers (> or =2 vs 1, p = 0.005). In conclusion, our findings suggested that HCC patients might exhibit enhanced innate immunity and reduced adaptive immunity compared with healthy volunteers. A higher percentage of B cells was found in patients with more advanced HCC compared with patients with early stage HCC, which might serve as an indicator of the severity of HCC.