1. Biomatrix/Polymer Composite Material for Heart Valve Tissue Engineering 
Christof Stamm, MD, Amir Khosravi, MD, Niels Grabow, MS, Kathleen Schmohl, PhD, Nadine Treckmann, BS, Anne Drechsel, BS, Ma Nan, PhD, Klaus-Peter Schmitz, PhD, Axel Haubold, PhD, Gustav Steinhoff, MD 
The Annals of Thoracic Surgery 
Volume 78, Issue 6, Pages (December 2004)
DOI: /j.athoracsur

2. Fig 5
Gross morphology of the two porcine biomatrix/polymer hybrid valves 12 weeks after implantation in pulmonary position in sheep. (A) The first valve was completely degenerated probably due to bacterial endocarditis. (B) The second valve was in excellent condition, with near-normal gross morphology.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )

3. Fig 1
Decellularization and polymer coating of porcine aortic valves. (A and B) Hematoxylin & eosin stain of the aortic media (A) before and (B) after enzymatic decellularization demonstrates complete removal of all cellular material. (C–E) Electron microscopy of the luminal valve surface (C) before decellularization, (D) after decellularization, and (E) after polymer penetration (here: P3/4HB). Note that the modified polymer penetration process leaves the surface porous, facilitating recipient cell adhesion and penetration.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )

4. Fig 2
Cell proliferation on biomatrix/polymer hybrid tissue in vitro (MTS test). (A) Cultivated L929 mouse fibroblasts; (B) mixed population of human myofibroblasts and endothelial cells. Although mouse fibroblasts appear to proliferate on P4HB and P3/4HB only, with virtually no cell growth on P3HB, there is good proliferation of human cells on all tested polymers. (OD = optical density; P3HB = poly[3-hydroxybutyrate]; P4HB = poly[4-hydroxybutyrate]; P3/4HB = poly[3-hydroxybutyrate-co-4-hydroxybutyrate].)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )

5. Fig 3
Activation of the cellular clotting system, plasmatic clotting system, and complement system in human plasma incubated with decellularized matrix and biomatrix/polymer hybrid tissue assessed by ELISA for (A) platelet factor 4, (B) prothrombin fragments F1 and F2 (prothrombin), and (C) C3a-des-Arg. Shown are representative sets of experiments using the same plasma sample. In the xenogenic setting (porcine matrix incubated with human plasma) polymer coating of decellularized matrix attenuated the activation of both cellular and plasmatic clotting system, while complement C3 activation remained unchanged. (P3HB = poly[3-hydroxybutyrate]; P4HB = poly[4-hydroxybutyrate]; P3/4HB = poly[3-hydroxybutyrate-co-4-hydroxybutyrate].)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )

6. Fig 4
(A) Explanted abdominal aorta of a rabbit 12 weeks after implantation of a patch consisting of decellularized human aortic wall seen from the adventitial aspect. The arrow indicates the patch. (B–D) Photomicrographs of explanted specimens 12 weeks after implantation (hematoxylin & eosin staining; original magnification 100×). The solid arrows indicate patch material; interrupted arrows indicate neoelastica interna. (B) Decellularized uncoated matrix is clearly distinct from the native aortic tissue with no signs of integration or resorption. There are no regions of calcification, moderate inflammatory infiltration, and formation of a thick neoelastica interna. (C) Matrix coated with P4HB. The patch is partially resorbed; the remaining material is heavily calcified. There is formation of a neoelastica interna as well as significant adventitial thickening. (D) P3HB-coated hybrid tissue is partially reabsorbed and well integrated in the native aortic tissue. There is little inflammatory infiltration, thin neoelastica interna, and near-normal adventitial tissue.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )

7. Fig 6
Xenogenic biomatrix/polymer hybrid valve 12 weeks after implantation in aortic position in sheep. (A) Gross morphology reveals the valve is in good condition, and the distal and proximal suture as well as both coronary orifices are clearly visible. The arterial wall lining is smooth, the leaflets are delicate and freely mobile; (B) cross section through a leaflet and its hinge point at the conduit wall (Mason's trichrome staining). The collagenous valve scaffold is intact. There is some intimal thickening with inflammatory infiltration on the luminal aspect of the leaflet. Panels C–F reveal the arterial wall of the conduit (hematoxylin & eosin stain): (C) hyperplasia of the tunica intima (arrows), for comparison; (D) shows the native aorta of the same animal; (E) tunica media of the arterial conduit wall in which, at this point, only few cells appear to have migrated into the media of the conduit wall; (F) for comparison, the native aortic media of the same animal is illustrated.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )

8. Fig 7
Immunohistology staining of a xenogenic biomatrix/polymer hybrid valve leaflet in aortic position 12 weeks after implantation in sheep. (A) CD31 staining demonstrating a confluent layer of endothelial cells covering the leaflet predominantly on the luminal aspect but also on the mural surface (original magnification ×100). (B) Higher magnification (×1000) illustrating a monolayer of endothelial cells with multiple CD31+ cells migrating into inner layers of the leaflet. (C) Leaflet stained for smooth muscle actin (×400); multiple SMA+ cells are integrated in the fibrous scaffold of the hybrid valve tissue. (D) Stain of the corresponding negative control.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )

9. Fig 8
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )