Inhalation of acrolein, a highly reactive aldehyde, causes lung edema. The underlying mechanism is poorly understood and there is no effective treatment. In this study, we demonstrated that acrolein not only dose-dependently induced lung edema but also promoted LPS-induced acute lung injury. Importantly, acrolein-induced lung injury was prevented and rescued by Alda-1, an activator of mitochondrial aldehyde dehydrogenase 2. Acrolein also dose-dependently increased monolayer permeability, disrupted adherens junctions and focal adhesion complexes, and caused intercellular gap formation in primary cultured lung microvascular endothelial cells (LMVECs). These effects were attenuated by Alda-1 and the antioxidant N-acetylcysteine, but not by the NADPH inhibitor apocynin. Furthermore, acrolein inhibited AMP-activated protein kinase (AMPK) and increased mitochondrial reactive oxygen species levels in LMVECs-effects that were associated with impaired mitochondrial respiration. AMPK total protein levels were also reduced in lung tissue of mice and LMVECs exposed to acrolein. Activation of AMPK with 5-aminoimidazole-4-carboxamide-1-β-4-ribofuranoside blunted an acrolein-induced increase in endothelial monolayer permeability, but not mitochondrial oxidative stress or inhibition of mitochondrial respiration. Our results suggest that acrolein-induced mitochondrial dysfunction may not contribute to endothelial barrier dysfunction. We speculate that detoxification of acrolein by Alda-1 and activation of AMPK may be novel approaches to prevent and treat acrolein-associated acute lung injury, which may occur after smoke inhalation.

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Adults with sickle cell disease (SCD) experience acute and chronic complications and die prematurely. When taken at maximum tolerated dose (MTD), hydroxyurea prolongs survival; however, it has not consistently reversed organ dysfunction. Patients also frequently do not take hydroxyurea, at least in part because of physician discomfort with prescribing hydroxyurea. We sought to develop a computer program that could easily titrate hydroxyurea to MTD. This was a single-arm, open-label pilot study. Fifteen patients with homozygous SCD were enrolled in the protocol, and 10 patients were followed at baseline and then for 1 year after hydroxyurea initiation or dose titration. Fetal hemoglobin significantly increased in all 10 patients from 8.3% to 25.1% (P < .001). Nine patients were titrated to MTD in an average of 7.9 months, and the tenth patient's hydroxyurea dose was increased to 33 mg/kg/day. Computer program dosing recommendations were the same as manual dosing decisions made using the same algorithm for all patients and at all times. We also evaluated markers of cardiopulmonary, liver and renal damage. Although cardiopulmonary function did not significantly improve, direct bilirubin and alanine aminotransferase levels significantly decreased (P < .001 and P < .01, respectively). Last, although kidney function did not improve, degree of proteinuria was significantly reduced (P < .05). We have developed a computer program that reliably titrates hydroxyurea to MTD. A larger study is indicated to test the program either as a computer program or a downloadable application.

Background: Sickle cell disease (SCD) is typically characterized as a red blood cell disorder but our understanding of the effects on the immune system is limited. Patients with sickle cell disease have been shown to have unique inflammatory profiles, immune phenotypes and function. Others have shown that during vaso-occlusive crises patients with SCD have elevated counts of neutrophils, monocytes, and cytokines as well as increased activity of invariant natural killer T cells (iNKT).We have previously shown that hydroxyurea use is associated with a normalization of the increased NK cell number and function. While there are studies that describe on the effects of single therapy, there is little known about combination therapy. Therefore, our study investigated immunological changes in pediatric patients on combination therapy, which was defined as hydroxyurea added to chronic red blood cell transfusion treatment. Methods: Patient data and peripheral blood samples were collected from an ongoing pilot study of combination therapy hydroxyurea and simple chronic transfusion in patients with SCD previously on chronic transfusion for stroke prevention. A total of 11 patients with hemoglobin SS were studied at two time points; baseline (on chronic RBC transfusion only) and 3 months follow up after initiation of hydroxyurea 20 mg/kg/day. Comparisons were performed using paired t-tests with a p-value <0.05 being considered significant. Results: T, B and NK cell percentage was similar between baseline and after 3 months of combination therapy 62.5% (44.3-71.9) vs 67% (17.6-82.7), 16.29%(8.15-30.2) vs. 13.26% (1.07-32.8) and 7.79% (4.16-14.7) vs. 6.88 (1.54-21) (p>0.05). There were no significant differences between markers of NK cell activation between baseline and 3 months as follows: NKG2D 4.89% (0.47-28.4) vs. 24.38% (0.88-63), and NKp30 8.40% (0.81-58.7) vs. 32.42% (0.45-86.9). However there was a significant decrease in the percentage of mature (CD57+) NK cells 33.8% (10.7-67.6) vs. 23.07%(4.23-37), p =0.005. Similar results were also seen when using absolute values of the different lymphocyte subsets. Conclusion: Combination therapy appears to not affect overall percentages of B, T and NK cells but does appear to decrease the percentage of mature CD57+ NK cells that are known to have increased cytolytic activity. We plan to investigate the implications of these findings using NK functional studies such as cytotoxicity assays and cytotoxic granule release to further elucidate if combination therapy can lead to a decrease in NK cell function to normal levels. Additionally we plan to assess the effect on the immune parameters at 1 year as the hydroxyurea effect is likely time-dependent. These findings may have implications for patients on chronic transfusion therapy who plan to undergo bone marrow transplantation where a reduction in the potential for graft rejection by NK cells is desired. Disclosures No relevant conflicts of interest to declare.