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Background: Isolated heart preparations are often used for myocardial research, but can become complex and difficult when blood is used as the perfusate. We compared the utility and effectiveness of a parabiotic isolated heart system perfused from a support animal to an equivalent system supported by a pediatric membrane oxygenator. Materials and methods: Whole blood reperfused rabbit hearts were supported on a standard Langendorff column by either a parabiotic support animal (n = 10), or an in-line pediatric membrane oxygenator (n = 12). Support animals were mechanically ventilated, and hemodynamically monitored. Perfusate acid-base balance, oxygen, carbon dioxide, bicarbonate, and lactate levels were serially monitored during 120 min of perfusion. Results: One-hundred percent of experiments supported with an oxygenator completed the evaluation period without instability, while 40% of parabiotic-supported experiments were terminated early because of donor animal hemodynamic instability (P < 0.0001). Parabiotic experiments developed a refractory acidosis (pH at 120 min: parabiotic 7.31 ± 0.14 versus oxygenator 7.42 ± 0.4, P = 0.01) related to a progressive rise in lactate (at 120 min: parabiotic 4.0 ± 2.6 mmol/L versus oxygenator 0.71 ± 1.3 mmol/L, P < 0.01). Parabiotic experiments demonstrated inferior oxygenation than oxygenator experiments (pO2 313 ± 72 mmHg versus 500 ± 42 mmHg, P < 0.0001). In this and other experiments, membrane oxygenators have been reused up to 25 times. Conclusions: Small animal isolated heart experiments perfused with blood are more successful, more efficient, and more cost effective when supported with a membrane oxygenator rather than a support animal. Membrane oxygenators reduce complexity, variability, and animal wastage in isolated heart experiments. [Copyright &y& Elsevier]

Background. Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis. We hypothesized that a combination of recombinant angiogenic proteins might induce myocardial VEGF production and cause a shift in the mRNA signal produced.Materials and methods. The left ventricles of New Zealand white rabbits were injected with 500 μL of saline, basic fibroblast growth factor (bFGF), platelet-derived growth factor-AB (PDGFAB), platelet-derived growth factor-BB (PDGFBB), bFGF + PDGFAB, or bFGF + PDGFBB. Myocardial VEGF production was analyzed by ELISA while mRNA splice variants were analyzed by RT-PCR 3 and 7 days after injection.Results. PDGFBB alone caused the most pronounced induction of VEGF. Three days after injection the induction of VEGF by PDGFBB was significant compared to all treatment groups, except the bFGF + PDGFBB group. Induction of VEGF by PDGFBB was associated with a decrease in mRNA production of VEGF121 within the myocardium.Conclusions. Injection of PDGFBB induces significant production of VEGF within the myocardium. This induction of VEGF production is associated with a shift toward other, less soluble forms of VEGF. These findings may allow more precise regulation of the myocardial response to therapeutic angiogenesis. [Copyright &y& Elsevier]