Impact of Pumps on Internal Thoracic Arteries (IPITA)

for each patient, 2 fresh segments of ITA (Time 1 and Time 2) stored in PSS were analyzed. On day+1, these segments were mounted on a wire-myograph (DMT, Aarhens, DK) . Two tungsten wires (25 μm diameter) were inserted into the lumen of the arteries and connected to a force transducer and a micrometer, respectively. The arteries were bathed in the PSS solution. Wall tension, equivalent to intra-arterial pressure (90 mmHg), was applied and the blood vessels were allowed to stabilize for thirty minutes. Arterial contractility was assessed with phenylephrine (PE, 10 μmol/L). Acetylcholine-induced (Ach 10 μmol/L) relaxation was then obtained after phenylephrine-induced preconstruction (50% of maximal contraction) in the presence or in the absence of the NO synthesis blocker L-NMMA (3.10-4 mol/L) and in the presence or in the absence of the COX synthesis blocker Indomethacin (10-5 mol/L).

: dihydroethidium staining (DHE, Sigma-Aldrich) was used to evaluate the in-situ levels of superoxide anions (O2-). DHE is permeable to cells and is oxidized by superoxide (O2-) to fluorescent products that are trapped by intercalation into the DNA. Sections (10 μm thickness) were incubated with DHE (1 μmol/L) in phosphate-buffered solution (PBS) and DAPI (4',6'-diamidino-2-phénulindole-Molecular probes, Invitrogen) for nuclear cells Fluorescent images of ethidium bromide were obtained using a confocal microscope (Nikon Eclipse TE2000S).

sections (10 μm thickness) of arteries were rehydrated by 500 μl of PBS during 10 minutes and fixated with 200 μl of paraformaldehyde (PFA) (pH = 7.4, room temperature) and then were rinsed by PBS. Permeabilization with 200 μl of PBS-BSA (Bovine Serum Albumin - Sigma) 10% - Tween 0.1% during 40 minutes and then saturation with PBS-BSA 10% during 40 minutes were performed. Sections were incubated overnight with 100 μl of anti-CD45 antibody at 1/500th dilution for leukocyte staining or anti-CD80 antibody at 1/200th dilution for lymphocyte staining. Antibodies were labelled with a red fluorochrome (Phycoerythrine). Karyoplasm was stained blue by DAPI solution. On day+1, sections were rinsed with PBS and analyzed with the confocal microscope. Fluorescent images were quantified with the ImageJ (NIH) software.

Sections of ITAs were dried and stored at -80°C in RNA later Stabilization Reagent (Qiagen). RNA extraction was performed using the RNeasy® micro kit (Qiagen). 500 ng of RNA extracted from each artery were used to synthesize cDNA using the QuantiTect® Reverse Transcription kit (Qiagen). Quantitative real-time PCR was performed with Sybr® Green PCR Master Mix (Applied Biosystems) using a Light cycler 480 Real-Time PCR System (Roche).

Serial arterial blood samples for elastase and for SC5b-9, marker of terminal complement complex activation, were collected at Time 1 and Time 2. Specimens were centrifuged (10 minutes, 3,000 rpm, 4°C) immediately to obtain plasma which was stored at - 80°C before analysis. Enzyme-linked immunosorbent assay techniques were used from 10 μl of plasma to measure terminal complement (SC5b-9; Quidel, San Diego, CA, USA) and 50 μl of plasma for neutrophil elastase (Neutrophil ELA2, Assay pro, St Charles, USA). The limit of sensitivity of each assay undertaken was as follows: SC5b-9 = 16 ng/mL and elastase = 20 ng/mL.