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BACKGROUND: Heart transplantation remains the gold standard for end-stage heart failure, with current ex vivo organ storage times limited to 4 to 6 h before critical tissue damage occurs. Many preservation solutions exist in an attempt to limit both ischemic and reperfusion damage. In order to compare the effects of various storage solutions, mitochondrial function can be used to provide a sensitive analysis of cellular metabolic function. METHODS: Experimental plates were seeded with cardiac myoblasts and kept in suspended animation for either 4 or 8 h at either 4o or 21 °C, in Celsior®, Perfadex®, or Somah storage solutions. Cells were then reanimated for 1 h at 37 °C to simulate a reperfusion or clinical transplant scenario. Cellular bioenergetics were measured immediately thereafter to examine biochemical differences between preservation solutions and their effectiveness on preserving metabolic function. RESULTS: The oxygen consumption rates of Somah solution were significantly higher than Celsior® and Perfadex® at 4 °C, with the exception of Perfadex® at 4o for 4 h. This effect was sustained up to 8 h. At 21 °C, oxygen consumption rates of Somah solution are significantly higher than Celsior® and Perfadex® at basal conditions after 4 h, but this effect is not sustained after 8 h. CONCLUSIONS: The purpose of this experiment was to study the efficacy of various preservation solutions on a mitochondrial level. The significantly higher oxygen consumption rates of Somah at 4 °C suggests that Somah solution may have the ability to protect cellular mitochondrial integrity, improve transplanted organ function by reducing ischemic-reperfusion injury, and thereby improve transplant outcomes. Given that Somah offers benefits over Celsior® and Perfadex® at 4 °C, it should be a target in future organ preservation solution research.

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Regenerative medicine, particularly decellularization-recellularization methods via whole-organ tissue engineering, has been increasingly studied due to the growing donor organ shortage. Though numerous decellularization protocols exist, the ideal decellularization protocol for optimal recellularization is unclear. This study was performed to optimize existing heart decellularization protocols and compare current methods using the detergents SDS (sodium dodecyl sulfate), Triton X-100, OGP (octyl ß-D-glucopyranoside), and CHAPS (3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate) through retrograde aortic perfusion via aortic cannulation of a whole porcine heart. The goal of decellularization is to preserve extracellular matrix integrity and architecture, which was analyzed in this study through histology, microscopy, DNA analysis, hydroxyproline content analysis, materials analysis and angiography. Effective decellularization was determined by analyzing the tissue organization, geometry, and biological properties of the resultant extracellular matrix scaffold. Using these parameters, optimal decellularization was achieved between 90 and 120 mmHg pressure with 3% SDS as a detergent. Relevance for patients: This study provides important information about whole heart decellularization, which will ultimately contribute to heart bioengineering.

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Since the creation of SynCardia's 50 cc Total Artificial Hearts (TAHs), patients with irreversible biventricular failure now have two sizing options. Herein, a case series of three patients who have undergone successful 50 and 70 cc TAH implantation with complete closure of the chest cavity utilizing preoperative "virtual implantation" of different sized devices for surgical planning are presented. Computed tomography (CT) images were used for preoperative planning prior to TAH implantation. Three-dimensional (3D) reconstructions of preoperative chest CT images were generated and both 50 and 70 cc TAHs were virtually implanted into patients' thoracic cavities. During the simulation, the TAHs were projected over the native hearts in a similar position to the actual implantation, and the relationship between the devices and the atria, ventricles, chest wall, and diaphragm were assessed. The 3D reconstructed images and virtual modeling were used to simulate and determine for each patient if the 50 or 70 cc TAH would have a higher likelihood of successful implantation without complications. Subsequently, all three patients received clinical implants of the properly sized TAH based on virtual modeling, and their chest cavities were fully closed. This virtual implantation increases our confidence that the selected TAH will better fit within the thoracic cavity allowing for improved surgical outcome. Clinical implantation of the TAHs showed that our virtual modeling was an effective method for determining the correct fit and sizing of 50 and 70 cc TAHs.

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BACKGROUND: Adipose-derived stem/stromal cells (ASCs) isolated from the stromal vascular fraction are a source of mesenchymal stem cells that have been shown to be beneficial in many regenerative medicine applications. ASCs are an attractive source of stem cells in particular, due to their lack of immunogenicity. This study examines differences between mitochondrial bioenergetic profiles of ASCs isolated from adipose tissue of five peri-organ regions: pericardial, thymic, knee, shoulder, and abdomen. RESULTS: Flow cytometry showed that the majority of each ASC population isolated from the adipose tissue of 12 donors, with an n = 3 for each tissue type, were positive for MSC markers CD90, CD73, and CD105, and negative for hematopoietic markers CD34, CD11B, CD19, and CD45. Bioenergetic profiles were obtained for ASCs with an n = 4 for each tissue type and graphed together for comparison. Mitochondrial stress tests provided the following measurements: basal respiration rate (measured as oxygen consumption rate [pmol O2/min], ATP production, proton leak, maximal respiration, respiratory control ratio, coupling efficiency, and non-mitochondrial respiration. Glycolytic stress tests provided the following measurements: basal glycolysis rate (measured as extracellular acidification rate [mpH/min]), glycolytic capacity, glycolytic reserve, and non-glycolytic acidification. CONCLUSIONS: The main goal of this manuscript was to provide baseline reference values for future experiments and to compare bioenergetic potentials of ASCs isolated from adipose tissue harvested from different anatomical locations. Through an investigation of mitochondrial respiration and glycolysis, it was demonstrated that bioenergetic profiles do not significantly differ by region due to depot-dependent and donor-dependent variability. Thus, although the physiological function, microenvironment and anatomical harvest site may directly affect the characteristics of ASCs isolated from different organ regions, the ultimate utility of ASCs remains independent of the anatomical harvest site.