Evaluation of humoral immune response to donor HLA after implantation of cellularized versus decellularized human heart valve allografts.

We have evaluated the development of antibodies in response to donor allograft valve implant in patients who received cellularized and decellularized allografts and determined possible immunogenic epitopes considered responsible for antibodies reactivity. Serum samples from all recipients who received cellularized allografts or decellularized allografts were collected before valve replacement and at 5, 10, 30 and 90 days post-operatively and frozen until required. Tests were performed using the Luminex-based single human leukocyte antigen (HLA)-A, -B, -C and HLA-DR, -DQ antigen microsphere assay. To determine possible immunogenic epitopes, we used the HLAMatchmaker (HLAMM) software if applicable. Decellularized grafts elicited lower levels of anti-HLA class I and II antibody formation after implantation than cellularized allografts. All patients from cellularized group presented donor-specific antibodies class I and II within 3 months of observation period. In HLAMM analysis, the cellularized group had significantly higher numbers of immunogenic epitopes than decellularized group for both class I and II (p: 0.002 - cl I / p: 0.009 - cl II / p: 0.004 - cl I and II). Our findings demonstrate that the anti-HLA antibodies detected in the cellularized group were against donor HLA possible immunogenic epitopes and that in the decellularized group the anti-HLA antibodies were not against donor HLA possible immunogenic epitopes. These findings lead us to suggest that choosing sodium dodecyl sulfate decellularization process is the best alternative to decrease the immunogenicity of allograft valve transplant.

Antioxidant capacity of phenolic and related compounds: correlation among electrochemical, visible spectroscopy methods and structure-antioxidant activity.

We investigated the antioxidant activity of phenylpropionic acids--caffeic (CAF), ferulic (FER), para-coumaric (COU) and cinnamic (CIN)--and phenolic acids and related compounds--gallic (GAL), methyl gallate (meGAL), vanillic (VAN) and gentisic (GEN)--using visible spectroscopy, inhibition of nitroblue tetrazolium (NBT) reduction, and electrochemical methods including cyclic voltammetry and potentiometry. In the spectroscopic assays, only CAF, GAL and meGAL were able to inhibit NBT reduction. The same compounds showed the lowest oxidation potentials (Epa) and the highest redox potentials deltaE) in the cyclic voltammetric and potentiometric studies, respectively. In addition, it was observed that the greater the number of hydroxyls linked to the aromatic ring, the greater was the antioxidant activity of the analysed compounds. The correlations of Spermann--used to compare the methods between themselves and the methods with the relationship structure-antioxidant activity--were r = -0.9762 for the cyclic voltammetric-potentiometric methods. r = 0.8333 for the inhibition of NBT reduction-potentiometric methods and r = -0.8095 for the inhibition of NBT reduction-cyclic voltammetric methods. The correlations for cyclic voltammetric, potentiometric and inhibition of NBT reduction methods-number of hydroxyls linked to the aromatic ring were r = -0.9636, 0.9636 and 0.9142, respectively. These findings indicate that the electrochemical methods together with spectroscopic studies are a good tool to evaluate the antioxidant activity of substances.