Background-We previously reported that tumor necrosis-factor-␣ (TNF-␣) can mimic classic ischemic preconditioning (IPC) in a dose-and time-dependent manner. Because TNF-␣ activates the signal transducer and activator of transcription-3 (STAT-3), we hypothesized that TNF-␣-induced preconditioning requires phosphorylation of STAT-3 rather than involving the classic prosurvival kinases, Akt and extracellular signal-regulated kinase (Erk) 1/2, during early reperfusion. Methods and Results-Isolated, ischemic/reperfused rat hearts were preconditioned by either IPC or low-dose TNF-␣ (0.5 ng/mL). Western blot analysis confirmed that IPC phosphorylated Akt and Erk 1/2 after 5 minutes of reperfusion (Akt increased by 34Ϯ6% and Erk, by 105Ϯ28% versus control; PϽ0.01). Phosphatidylinositol 3-kinase/Akt inhibition (wortmannin) or mitogen-activated protein kinase-Erk 1/2 kinase inhibition (PD-98059) during early reperfusion abolished the infarct-sparing effect of IPC. In contrast, TNF-␣ preconditioning did not phosphorylate these kinases (Akt increased by 7Ϯ7% and Erk, by 17Ϯ14% versus control; PϭNS). Neither wortmannin nor PD-98059 inhibited TNF-␣-mediated cardioprotection. However, TNF-␣ and IPC both phosphorylated STAT-3 and the proapoptotic protein Bcl-2 antagonist of cell death (BAD) (STAT-3 increased by 58Ϯ17% with TNF-␣ or by 68Ϯ12% with IPC; BAD increased by 75Ϯ8% with TNF-␣ or by 205Ϯ20% with IPC; PϽ0.01 versus control), thereby activating the former and inactivating the latter. The STAT-3 inhibitor AG 490 abolished cardioprotection and BAD phosphorylation with both preconditioning stimuli. Conclusions-Activation of the classic prosurvival kinases (Akt and Erk 1/2) is not essential for TNF-␣-induced preconditioning in the early reperfusion phase. We show the existence of an alternative protective pathway that involves STAT-3 activation specifically at reperfusion in response to both TNF-␣ and classic IPC. This novel prosurvival pathway may have potential therapeutic significance. (Circulation. 2005;112:3911-3918.)

Most in vivo models of ischaemic stroke target the middle cerebral artery and a spectrum of stroke severities, from mild to substantial, can be achieved. This review describes opportunities to improve the in vivo modelling of ischaemic stroke and animal welfare. It provides a number of recommendations to minimise the level of severity in the most common rodent models of middle cerebral artery occlusion, while sustaining or improving the scientific outcomes. The recommendations cover basic requirements pre-surgery, selecting the most appropriate anaesthetic and analgesic regimen, as well as intraoperative and post-operative care. The aim is to provide support for researchers and animal care staff to refine their procedures and practices, and implement small incremental changes to improve the welfare of the animals used and to answer the scientific question under investigation. All recommendations are recapitulated in a summary poster (see supplementary information).

Background-Increased serotonin (5-hydroxytryptamine, 5-HT) transporter activity has been observed in human familial pulmonary hypertension. Methods and Results-We investigated pulmonary hemodynamics and the development of hypoxia-induced pulmonary hypertension and pulmonary vascular remodeling in mice overexpressing the gene for the 5-HT transporter (5-HTTϩ mice). Right ventricular pressure was elevated 3-fold in normoxic 5-HTTϩ mice compared with their wild-type controls. Hypoxia-induced increases in right ventricular hypertrophy and pulmonary vascular remodeling were also potentiated in the 5-HTTϩ mice. 5-HTT-like immunoreactivity, protein, and binding sites were markedly increased in the lungs from the 5-HTTϩ mice. Hypoxia, however, decreased 5-HT transporter immunoreactivity, mRNA transcription, protein, and binding sites in both wild-type and 5-HTTϩ mice. Conclusions-Increased