Systemic administration of hemoglobin improves ischemic wound healing.

BACKGROUND: Oxygen plays multifaceted roles in wound healing, including effects on cell proliferation, collagen synthesis, angiogenesis, and bacterial killing. Oxygen deficit is a major factor in the pathogenesis of chronic wounds. MATERIALS AND METHODS: We present a novel mechanism for oxygen delivery to ischemic wounds by systemic administration of an oxygen carrier substitute derived from bovine hemoglobin (IKOR 2084) in our ischemic rabbit ear wound model. The wound healing indexes, including epithelial gap and neo-granulation tissue area, were histologically analyzed. In situ expression of endothelial cells (CD31+) and proliferative cells (Ki-67+) were examined by immunohistochemistry analysis. The messenger RNA expression of collagen I, III, and vascular endothelial growth factor was measured by quantitative RT-PCR. Sirius Red staining was implemented for detection of collagen deposition, and terminal deoxynucleotidyl transferase dUTP nick end labeling analysis was performed to examine dermal cellular apoptosis. RESULTS: Systemic administration of IKOR 2084 significantly improved oxygen tension of ischemic tissue. When compared with saline controls, IKOR 2084 treatment enhanced wound repair as demonstrated by a reduced epithelial gap and increased granulation tissue area. The expression of Ki-67+, CD31+, vascular endothelial growth factor and collagen was also enhanced by IKOR 2084 administration. Moreover, apoptosis analysis in the wounds showed that cell survival in the dermis was increased by systemic IKOR 2084 administration. CONCLUSIONS: Our study suggests that systemic delivery of IKOR 2084 ameliorates hypoxic state, subsequently promotes angiogenesis, cellular proliferation, and collagen synthesis, attenuates hypoxia-induced apoptosis, and improved ischemic wound healing.

Lipoprotein associated phospholipase A2 inhibition reduces generation of oxidized fatty acids: Lp-LPA2 reduces oxidized fatty acids.

PURPOSE: Lipoprotein associated phospholipase A(2) (Lp-PLA(2)) is an emerging cardiovascular risk marker. After low-density lipoprotein (LDL) oxidation, Lp-PLA(2) generates oxidized nonesterified fatty acids and lysophosphatidylcholine, both of which have demonstrated proinflammatory and proapoptotic activities. Through the use of a selective inhibitor of Lp-PLA(2) (SB-677116), we investigated whether Lp-PLA(2) participates in the ex vivo generation of oxidized fatty acids (ox-FA). METHODS: Due to the higher correlation between Lp-PLA(2) activity and small LDL particles, we investigated the effects of a selective Lp-PLA(2) inhibition on production of ox-FA in metabolic syndrome subjects with small LDL size <20.5 nm. Whole blood samples were incubated with vehicle (0 microM) or SB-677116 for 6 h at two different concentrations (0.3, 3.0 microM) to determine the effects of inhibitor on Lp-PLA(2) activity, the formation of oxidized esterified and nonesterified hydroxy-fatty acid (OH-FA) or ox-FA in 24 subjects. RESULTS: Whole blood incubation with Lp-PLA(2) inhibitor (0.3, 3.0 microM) reduced multiple C-18 OH-FA subclasses (p < 0.05 versus control). For the highly redox-sensitive 9-OH-FA, there was a concentration-dependent reduction in Lp-PLA(2) activity and 9-OH-FA (p (trend) = 0.0016) CONCLUSIONS: In conclusion, selective inhibition of Lp-PLA(2) reduced levels of OH-FA generated in whole blood of metabolic syndrome patients. These novel findings suggest that Lp-PLA(2) inhibition may attenuate some noxious downstream effects of lipid peroxidation that potentially include inflammatory responses.

Creatine kinase is an alpha myosin heavy chain 3'UTR mRNA binding protein.

Altered cardiac workload regulates the translation and localization of the alpha myosin heavy chain (alphaMyHC) messenger RNA through the 3' untranslated region (UTR) by protein-RNA interactions. We used the alphaMyHC 3'UTR from neonatal rat heart tissue in a gel shift analysis to find RNA binding proteins. One was identified by microsequencing as creatine kinase, brain form B (CKBB). The affinity of its binding interaction was evaluated using sense and antisense alphaMyHC 3'UTR and 3'UTR probes from myosin isoforms of 2B and 2X skeletal muscle. Removal of calcium by the chelating agent EGTA had a potentiating effect on the formation of the CKBB/alphaMyHC 3'UTR complex in vitro . Varying the concentration of ATP (0.1-1 mM) also enhanced this interaction, suggesting that autophosphorylation of CKBB is taking place. Our novel finding that CKBB, an energy transduction enzyme, binds to the RNA of the 3'UTR of the faster ATP consuming alphaMyHC suggests a possible regulatory linkage between the metabolic state of the cell and myosin isoform expression.