IntroductionWe previously showed that erythropoietin (EPO) attenuates the morphological signs of spinal cord ischemia/reperfusion (I/R) injury in swine [1] without, however, improving neurological function. The clinical use of EPO has been cautioned most recently due to serious safety concerns arising from an increased mortality in acute stroke patients treated with EPO and simultaneously receiving systemic thrombolysis [2]. Carbamylated EPO (cEPO) is an EPO derivative without erythropoietic activity and devoid of the EPO side eff ects, but with apparently well maintained cytoprotective qualities [3]. We therefore tested the hypothesis whether cEPO may be equally effi cient as EPO in reducing morphological as well as functional aortic occlusion-induced spinal cord I/R injury. Methods In a randomized and blinded trial pigs received either vehicle (control, n = 9), EPO or cEPO, respectively (n = 9 each; 5,000 IU/kg over 30 minutes before and during the fi rst 4 hours of reperfusion). Animals underwent 30 minutes of thoracic aortic balloon occlusion with catheters placed immediately downstream of the A. subclavia and upstream of the aortic trifurcation. Spinal cord function was assessed by motor evoked potentials (MEP as percentage of the amplitude before aortic occlusion) and lower limb refl exes (assessed as the subjective strength of response) for a period of 10 hours after reperfusion. Tissue damage was evaluated using Nissl staining. Results Both EPO-treated and cEPO-treated animals presented with attenuated spinal cord injury in the Nissl staining (median (quartile) percentage of damaged neurons in the thoracic segments: control 27 (25,44), cEPO 8 (4,10), and EPO 5 (5,7), P <0.001 vs control group; in the lumbar segments: control 26 (19,32), cEPO 7 (5,13), EPO 8 (5,10), P <0.001 vs control group). However, while only cEPO treatment was associated with recovery of the MEP amplitude to pre-occlusion values when compared with the control group (P <0.05), lower limb refl ex response was comparably restored stronger in both treatment groups (P <0.05 vs control). Conclusions In a clinically relevant porcine model mimicking aortic crossclamping during vascular surgery repair of thoracic aortic aneurysm, cEPO protected spinal cord function and integrity as eff ective as EPO when applied at equipotent doses. Acknowledgements Supported by the Deutsche Forschungs gemeinschaft (SCHE 899/2-2). References Introduction Unfolded protein response (UPR)-mediated apoptosis plays a pivotal role in ischemia-reperfusion injury. Sodium 4-phenylbutyrate (PBA) has been reported to act as a chemical chaperone inhibiting UPR-mediated apoptosis triggered by ischemia in various organs other than the heart. Therefore we investigated whether PBA reduces UPR-mediated apoptosis and protects against myocardial ischemia-reperfusion injury in mice. Methods C57BL/6 mice were subjected to 30 minutes LAD ischemia followed by reperfusion. PBA (100 mg/kg) or PBS (control) was administrated intraperitoneally just before ischemia. Apoptosis, infarct ...

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Objective To examine the effects of short-term cyclic stretch on apoptosis in alveolar type II cells (A549). To study in vitro the direct influence of alveolar type II cells on mechanical stretch. Methods A549 were treated with different doses of lipopolysaccharide (LPS), 0 ng/ml, 1 ng/ml, 10 ng/ml, 100 ng/ml, 1000 ng/ml, and then A549 were lengthened 5%, 15%, 30% using a FLEXCELL tension unit 4000, a vacuum-driven device that applies strain to cells, which were cultured in six-well plates coated with collagen-I, and 12 cycles/min for 4 hours. Apoptosis was measured using the flow cytometry method that measures annexin V and propidium iodide (PI) staining. The morphological changes of apoptotic cells were observed by transmission electron microscope. Results Apoptosis could be induced in alveolar type II cells (A549) by mechanical stretch. The percentage of annexin V + PI cells increased after being treated with cyclic stretch for 4 hours by 5%, 15%, 30% in all groups. The morphological features of apoptotic cells demonstrated by transmission electron microscope were as follows: shrinkage of the cell, chromatin condensation and aggregation under the nuclear membrane as a crescent or lump, membrane-encapsulated nuclear fragment or cell organ formed by invagination of the cell membrane, and apoptotic body formation followed by vacuolization. Conclusion Apoptosis induced by mechanical stretch and LPS is dose dependent. Mechanical stretch aggravates apoptosis especially in cells treated with LPS. Annexin V and PI double staining is a specific, sensitive, and quantitative method for analyzing apoptotic cells. It is also helpful to clarify the protective mechanism of low-volume ventilation in ARDS. Acknowledgement The study was funded by the 'One Hundred People' project of Shanghai Sanitary Bureau (03-77-20). Introduction Although extrapulmonary ALI/ARDS is a common clinical entity, most animal models used to study this disease are induced by direct lung injuries. Our intention was therefore to investigate whether a condition resembling ALI/ARDS develops during the course of a fecal peritonitis in pigs; in that case experimental peritonitis would also prove as a clinically relevant ARDS model. Methods In 10 anesthetized, mechanically ventilated, and instrumented pigs fecal peritonitis was induced by inoculating autologue feces pellets suspended in saline. Mechanical ventilation was set with VT = 8 ml/kg, FiO 2 to reach a SaO 2 target of >90%, PEEP = 10 cmH 2 O if PaO 2 /FiO 2 > 300 and 12 cmH 2 O if PaO 2 /FiO 2 < 300, and respiratory rate to obtain a PaCO 2 of 35-45 mmHg. Before as well as 12 and 24 hours after peritonitis induction we measured the PaO 2 /FiO 2 ratio, the total compliance of the respiratory system (C), calculated as VT/(P plateau -PEEP) and inspiratory airway resistance (R i ) calculated as (P max -P plateau ) / mean inspiratory flow. Data are mean [range]. Results For data see Table 1. During the course of the 24-hour study period, six of 10 animals developed gas exchange deteriorations consistent w...