Perfusion preservation maintains myocardial ATP levels and reduces apoptosis in an ex vivo rat heart transplantation model.

Background: Machine perfusion preservation improves reperfusion function of many solid organs, compared with conventional storage, but has received limited clinical attention in preserving hearts for transplantation. We evaluated representative extracellular (Celsior) and intracellular (University of Wisconsion) storage solutions using static and perfusion protective strategies over a clinically relevant preservation period.

Methods: Rat hearts were preserved for 200 minutes by either static storage or perfusion preservation in Celsior or University of Wisconsin solutions.

Lung preservation solution substrate composition affects rat lung oxidative metabolism during hypothermic storage.

Lungs harvested for transplantation utilize oxygen after procurement. We investigated the effects of storage solution substrate composition on pulmonary oxidative metabolism and energetics during the preservation interval. Rat lungs were harvested and stored at 10 degrees C in low-potassium dextran (LPD) solution.

Characterizing lung metabolism with carbon-13 magnetic resonance spectroscopy in a small-animal model: evidence of gluconeogenesis during hypothermic storage.

Experimental evidence suggests storing lungs inflated with oxygen and with oxidizable substrate improves results of lung transplantation. Glucose is included in the low-potassium-dextran (LPD) solution Perfadex to achieve this goal. The authors hypothesized that other substrates might be more effective.

Pyruvate-modified perfadex improves lung function after long-term hypothermic storage.

Background: Lungs harvested for transplantation are stored while inflated with oxygen, which can serve to support oxidative metabolism. However, strategies aimed at increasing graft metabolism during storage have received little attention. In this study, we added pyruvate to the preservation solution Perfadex and measured the effects on oxidative metabolism and reperfusion lung function.

Myocardial oxygen demand and redox state affect fatty acid oxidation in the potassium-arrested heart.

Background: Fatty acid (FA) metabolism is suppressed under conditions of cardioplegic arrest, but the mechanism behind this effect is unknown. We hypothesized that alterations in redox state and oxygen demand control myocardial FA utilization during potassium arrest.

Methods: Rat hearts were perfused with Krebs-Heinseleit buffer containing physiologic concentrations of FAs, ketones, and carbohydrates with unique (13)Carbon labeling patterns.

Expandable bioresorbable endovascular stent. I. Fabrication and properties.

A bioresorbable, expandable poly(L-lactic acid) stent has been designed, based on a linear, continuous coil array principle, by which multiple furled lobes convert to a single lobe upon balloon expansion, without heating. Stent strength and compliance are sufficient to permit deployment by a conventional balloon angioplasty catheter. Several multiple lobe configurations were investigated, with expansion ratios ranging from 1.

Effects of hypothermia on myocardial substrate selection.

Background: Hypothermia lowers the metabolic rate and increases ischemic tolerance but the effects of temperature on myocardial substrate selection are not well defined.

Methods: Isolated rat hearts were perfused with physiologic concentrations of 13C labeled lactate, pyruvate, acetoacetate, mixed long-chain fatty acids, and glucose. Hearts were cooled over 5 to 10 minutes to one of four target temperatures (37 degrees, 32 degrees, 27 degrees, or 17 degrees C), then perfused for an additional 30 minutes, freeze-clamped, and extracted.