There are clinically relevant differences in symptomatology, risk stratification, and efficacy of therapies between men and women with coronary artery disease. Sex-based differences in plaque attenuation after administration of bone marrow mononuclear cells (BMNCs) are unknown. Forty-five male and 57 female apolipoprotein-E knockout (apoE(-/-)) mice were fed a high-fat diet. At 14 weeks of age, animals received 4 biweekly intravenous sex-matched (males, n=11; females, n=13) or -mismatched (males, n=12; females, n=14) BMNCs obtained from C57BL6/J mice. The rest of the apoE(-/-) mice were vehicle treated (males, n=13; females, n=20) or were age-matched untreated controls (males, n=9; females, n=10). Aortic plaque burden, progenitor cell profiles in bone marrow (BM) and 22 circulating cytokines/chemokines were examined 1 week following the final injection. Only female BMNCs infused into male apoE(-/-) recipients significantly decreased plaque formation (P<0.001). This reparative response univariately correlated with increased CD34(+) (P=0.02), CD45(+) (P=0.0001), and AC133(+)/CD34(+) (P=0.001) cell percentages in the BM of recipients but not with total serum cholesterol or percentage of BM-CD31(+)/CD45(low) cells. In a multivariate analysis, BM-AC133(+)/CD34(+) and BM-CD45(+) percentage counts correlated with a lower plaque burden (P<0.05). Increased granulocyte colony-stimulating factor levels highly correlated with plaque attenuation (r=-0.86, P=0.0004). In untreated apoE(-/-) mice of either sex, BM-AC133(+)/CD34(+) cells rose initially and then fell as plaque accumulated; however, BM-AC133(+)/CD34(+) percentages were higher in females at all times (P
Background; Bioengineered solutions to failing cardiac tissue have been difficult to achieve due partially to adverse interactions between circulating blood and the engineered surface. The aim of this study was to determine if by using naturally-derived ECM and cultured endothelial cells, a bioengineered whole-heart vascular intima could be generated. The matrix substrate for organ culture was produced by a perfusion-based detergent decelluarization of cadaveric rat heart. This process maintained ECM protein integrity as indicated by a glycosaminoglycan assay, with ~ equivalent amounts present relative to cadaveric rat heart. Its acellular nature was confirmed by loss of > 96% DNA (p = 0.001) compared to normal rat heart. In vitro infusion of aqueous dye or Mercox resin suggested a complete arterial tree, with structural preservation of vascular conduits. In vivo perfusability of the ECM was demonstrated by heterotopic transplantation with anticoagulation (n=4) into RNU rats for 7 days. Recellularization of the vascular tree was attempted by In Vitro Langendorff perfusion of 2 x 107 rat aortal endothelial cells (ECs) followed by a 7d incubation with escalating pulsatile flow in a 3D bioreactor. CellTracker Green assessed EC viability and permitted visualization of engrafted cells by fluorescent microscopy. Vessels of different diameters contained “patches” of confluent endothelium with complete circumferential lining of many of the matrix conduits. ECs lining both chamber walls and trabeculae were also observed. Nuclear staining showed 537.8 +/− 67.6 ECs / mm2 on endocardial surfaces, as well as 311.7 +/− 61.8 ECs / mm2 in vessels. To enhance the delivery of cells into the ventricular walls, a microcanulization of the brachiocephalic artery with sustained aortal perfusion was undertaken. This technique diverted more cells to the vasculature and more broadly distributed the cells in each area resulting in a lower cell density; 199.8 +/− 25.0 ECs / mm2 in vessels vs 125.8 +/− 43.4 ECs / mm2 on endocardial surfaces. In conclusion, these data suggest that by using detergent prepared acellular ECM of a whole organ, generation of a complete endothelial lining of vascular structures may be possible.
Acellular matrices derived from animal and human cadaveric donor vessels or other tubular matrices are appropriate candidates for the creation of tissue- en-gineered, small-diameter, muscular arteries. Engi-neering principles have been used to design a bio-reactor and the necessary auxiliary systems for the reconstitution of a previously decellularized vascular matrix. The bioreactor enables the attachment of cells to the luminal and/or exterior surfaces of the matrix. For the recellularization procedure, the matrix is situated within a sealed compartment in order to maintain a sterile environment. The matrix is rotated continuously to assure a spatially uniform re-constitution. The auxiliary systems that serve the bioreactor are: (a) an oxygenator, (b) peristaltic pumps, one for conveying the internal cell medium and the other for conveying the external cell medium, (c) motor and gearing to create steady and controlled rotation, (d) reservoirs for the containment of the two media, and (e) tubing to convey the respective fluids and to interconnect the bioreactor culture chamber to the various auxiliary components. A recellularized matrix produced by the bioreactor demonstrated its capabilities to reconstitute a previously decellularized scaffold.
