Hydrogen Peroxide Generation of Copper/Ascorbate Formulations on Cotton: Effect on Antibacterial and Fibroblast Activity for Wound Healing Application

Greige cotton (unbleached cotton) is an intact plant fiber that retains much of the outer cotton fiber layers. These layers contain pectin, peroxidases, and trace metals that are associated with hydrogen peroxide (H2O2) generation during cotton fiber development. When greige cotton is subjected to a nonwoven hydroentanglement process, components of the outer cotton fiber layers are retained. When hydrated, this fabric can generate H2O2 (5–50 micromolar). This range has been characterized as inducing accelerated wound healing associated with enhanced cell signaling and the proliferation of cells vital to wound restoration. On the other hand, H2O2 levels above 50 micromolar have been associated with bacteriostatic activity. Here, we report the preparation and hydrogen peroxide activity of copper/ascorbate formulations, both as adsorbed and in situ synthesized analogs on cotton. The cooper/ascorbate-cotton formulations were designed with the goal of modulating hydrogen peroxide levels within functional ranges beneficial to wound healing. The cotton/copper formulation analogs were prepared on nonwoven unbleached cotton and characterized with cotton impregnation titers of 3–14 mg copper per gram of cotton. The copper/ascorbate cotton analog formulations were characterized spectroscopically, and the copper titer was quantified with ICP analysis and probed for peroxide production through assessment with Amplex Red. All analogs demonstrated antibacterial activity. Notably, the treatment of unbleached cotton with low levels of ascorbate (~2 mg/g cotton) resulted in a 99 percent reduction in Klebsiella pneumoniae and Staphylococcus aureus. In situ synthesized copper/ascorbate nanoparticles retained activity and did not leach out upon prolonged suspension in an aqueous environment. An assessment of H2O2 effects on fibroblast proliferation are discussed in light of the copper/cotton analogs and wound healing

Inducible Nitric Oxide Synthase Expression in Human Vein Grafts

Background: The patency of vascular reconstructive procedures is limited by the development of intimai hyperplasia (IH). Nitric oxide (NO) seems to be beneficial in abrogating this process. Currently, there is little information concerning inducible nitric oxide synthase (iNOS), the enzyme responsible for NO synthesis, and human vein grafts. The purpose of this study was to examine iNOS gene expression in human aortocoronary vein grafts (ACVG) and infrainguinal vein bypass grafts (IVG). Methods: Nonthrombosed sections from ACVG (n = 5), IVG (n = 5), and control saphenous vein (SV; n = 4) were harvested and processed for RNA isolation. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed on samples using 3P radioactively end labeled primers. Glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) was the internal control, and results were expressed as iNOS pmol/ GAPDH pmol. Results: There was a significant increase in the iNOS gene expresssion in the ACVG (0.049 ± 0.01) when compared with IVG (0.019 ± 0.001) or normal SV (0.011 ± 0.002; P ≤ 0.05). There was no significant difference between normal vein and the infrainguinal grafts. Sequencing of a fragment of the amplified 428 bp gene product confirmed 84% homology with the available gene bank human sequence. conclusions: This study proves that iNOS is expressed in human vein bypass grafts. Additionally, there is a significant elevation of iNOS message in human ACVGs compared with IVG or normal SV. This difference may be the result of the unique vascular beds supplied by these grafts. Ultimately, manipulation of iNOS expression may lead to therapies to alleviate IH in these grafts

Inducible Nitric Oxide Synthase Expression in Human Vein Grafts

Background: The patency of vascular reconstructive procedures is limited by the development of intimai hyperplasia (IH). Nitric oxide (NO) seems to be beneficial in abrogating this process. Currently, there is little information concerning inducible nitric oxide synthase (iNOS), the enzyme responsible for NO synthesis, and human vein grafts. The purpose of this study was to examine iNOS gene expression in human aortocoronary vein grafts (ACVG) and infrainguinal vein bypass grafts (IVG). Methods: Nonthrombosed sections from ACVG (n = 5), IVG (n = 5), and control saphenous vein (SV; n = 4) were harvested and processed for RNA isolation. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed on samples using 3P radioactively end labeled primers. Glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) was the internal control, and results were expressed as iNOS pmol/ GAPDH pmol. Results: There was a significant increase in the iNOS gene expresssion in the ACVG (0.049 ± 0.01) when compared with IVG (0.019 ± 0.001) or normal SV (0.011 ± 0.002; P ≤ 0.05). There was no significant difference between normal vein and the infrainguinal grafts. Sequencing of a fragment of the amplified 428 bp gene product confirmed 84% homology with the available gene bank human sequence. conclusions: This study proves that iNOS is expressed in human vein bypass grafts. Additionally, there is a significant elevation of iNOS message in human ACVGs compared with IVG or normal SV. This difference may be the result of the unique vascular beds supplied by these grafts. Ultimately, manipulation of iNOS expression may lead to therapies to alleviate IH in these grafts