The current results indicate that isoflurane-induced myocardial protection involves activation of the HIF-1 pathway that is mediated by the mammalian target of rapamycin.

We tested whether isoflurane preconditioning inhibits cardiomyocyte apoptosis and evaluated the role of the phosphatidylinositol-3-kinase (PI3K)/Akt pathway in anesthetic preconditioning and determined whether PI3K/Akt signaling modulates the expression of pro-and antiapoptotic proteins in anesthetic preconditioning. Six-month-old New Zealand rabbits subjected to 40 min of myocardial ischemia followed by 180 min of reperfusion were assigned to the following groups: ischemiareperfusion (I/R), isoflurane preconditioning and isoflurane plus PI3K inhibitors, wortmannin and 2-(4-morpholinyl)-8-phenyl-4H-L-benzopyran-4-one (LY294002) (0.6 and 0.3 mg/kg i.v., respectively). Sham-operated, wortmannin ϩ I/R, wortmannin ϩ sham, LY294002 ϩ I/R, and LY294002 ϩ sham groups were also included. Infarct size was assessed by triphenyltetrazolium chloride staining. Apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling and activated caspase-3 assays. Akt phosphorylation, Bax, Bcl-2, Bad, and phosphorylated Bad (phospho-Bad) expression was assessed by immunoblotting. Isoflurane preconditioning reduced infarct size compared with the I/R group: 22 Ϯ 4 versus 41 Ϯ 5% (p Ͻ 0.05). The percentage of apoptotic cells decreased in the isoflurane group (3.8 Ϯ 1.2%) compared with the I/R group (12.4 Ϯ 1.6%; p Ͻ 0.05). These results were also confirmed by the activated caspase-3 assay. Wortmannin and LY294002 inhibited the effects of isoflurane. Myocardial infarction increased to 44 Ϯ 3 and 45 Ϯ 2% and the percentage of apoptotic cells was 11.9 Ϯ 2.1 and 11.7 Ϯ 3.3%, respectively. Akt phosphorylation and Bcl-2 and phospho-Bad expression increased after isoflurane preconditioning, whereas Bax expression decreased. These effects were inhibited by wortmannin and LY294002. The data indicate that isoflurane preconditioning reduces infarct size and myocardial apoptosis after I/R. Activation of PI3K and modulation of the expression of pro-and antiapoptotic proteins may play a role in isoflurane-induced myocardial protection.Myocardial cell death via necrosis and apoptosis is the main feature of pathological conditions associated with ischemia and reperfusion. Reducing myocyte loss through suppression of cell death pathways represents a logical strategy to protect cardiac function. It has been shown that volatile anesthetics produce pharmacological preconditioning and protect the heart against myocardial infarction in a variety of experimental animal models as well as in humans (Cason et al., 1997;Cope et al., 1997;Tanaka et al., 2004a;Zaugg et al., 2004). The mechanisms by which volatile anesthetics protect the heart have been extensively investigated and are believed to involve activation of adenosine receptors (Kersten et al., 1997) and protein kinase C (Novalija et al., 2003b), release of reactive oxygen species (Mullenheim et al., 2002), and opening of ATP-regulated potassium channels (Pain et al., 2000).Ischemic preconditioning, a phenomenon whereby exposure of the myocardium to a brief ischemic...

Osteoporosis (OP) and atherosclerotic-cardiovascular diseases (and possibly dementia) constitute emerging age-related co-morbidity states that might share risk factors. Blood-born lipids, like LDL involved in atherosclerosis and apolipoprotein-E4 (ApoE4) involved in dementia, may also be implicated in development of OP. We examined osteoblast cell lines as a culture model for OP by exposure to lipoproteins. ApoE expression in Saos2 and U2OS osteoblasts was confirmed by PCR. ApoE4 did decrease cell counts relatively to ApoE3, especially in Saos2 cells in which it was less selective for cells with higher alkaline phosphatase (ALP, an osteoblast marker) activity than ApoE3. This associates with ApoE4, being a risk factor for both dementia and OP. Saos2, but not U2OS, showed a decrease in cell counts after 48 h exposure to native LDL (NLDL). Both cell lines had decreased cell counts already after 24 h when exposed to oxidized-LDL (OxLDL) for which Saos2 also showed a higher sensitivity than U2OS. Exposure of Saos2 to both, OxLDL at low concentration (5 microg/ml) and NLDL revealed a shrunken size cell fraction of 17-23% on the fluorescence-activated cell sorter (FACS) analysis. Such shrunken cell fraction was not seen when Saos2 cells were exposed to 50 microg/ml of OxLDL or to OxLDL combined with 10 nM dexamethasone (DEX, a stimulator of osteoprogenitor differentiation). DEX treatment has lysed the cells earlier than 24 h post exposure and has selected more resistant cells that did not show apoptotic shrinkage in the FACS analysis done after 24 h. We interpret this as a failure to detect the apoptotic cell fraction due to their lysis prior to the FACS analysis. Western blots performed at different time points (10 min, 30 min, 4 h, 24 h, and 48 h) under OxLDL + DEX revealed a fall in the positive regulator of pp60Src-kinase phosphotyrosine (pY)418 relative to the DEX controls during the first 4 h. This is consistent with DEX osteogenic induction, known to be negatively regulated by c-Src, although the pY418/pY529 ratios (negative/positive kinase regulation) fell only at the 10 min time point. Contrarily the pY418/pY529 ratio increased, relative to untreated controls, under 5 microg/ml and 50 microg/ml of NLDL at the 4 h time point and under 50 microg/ml NLDL only at the 10 min time point, being consistent with the ability of a higher dose of LDL to antagonize osteoblast differentiation. This could be even more acceptable if the NLDL would have become minimally oxidized during its long purification procedure. Under NLDL, the Bcl-2/Bax ratio was pro-apoptotic at 10 min, 30 min, and 4 h only under 50 microg/ml, whereas under OxLDL + DEX it was pro-apoptotic only after 4 h suggesting that additional pathways contribute to cell death. These results indicate that lipid effects on human osteoblast lines in culture may be used as a model to identify molecular targets shared between OP and atherosclerosis for intervention in this co-morbidity.

Familial Mediterranean fever (FMF) is an inherited disease whose manifestations are acute but reversible attacks of sterile inflammation affecting synovial and serosal spaces. The FMF gene (MEFV) was recently cloned, and it codes for a protein (pyrin/marenostrin) homologous to known nuclear factors. We previously reported the deficient activity of a C5a/interleukin (IL)–8 inhibitor, a physiologic regulator of inflammatory processes, in FMF serosal and synovial fluids. We now describe the concomitant expression ofMEFV and C5a/IL-8–inhibitor activity in primary cultures of human fibroblasts. Fibroblasts grown from synovial and peritoneal tissues displayed C5a/IL-8–inhibitor activity that could be further induced with phorbol myristate acetate (PMA) and IL-1β. Very low levels of chemotactic inhibitor were evident in skin fibroblast cultures or in peritoneal and skin fibroblasts obtained from FMF patients. MEFV was expressed in peritoneal and skin fibroblasts at a lower level than in neutrophils and could be further induced by PMA and IL-1β. In the FMF cultures, the MEFV transcript carried the M694V mutation, consistent with the genetic defect found in patients with this disease. MEFV was also expressed in other cell lines that do not produce C5a/IL-8 inhibitor. These findings suggest that human primary fibroblast cultures express MEFV and produce C5a/IL-8–inhibitor activity. The interrelationship between pyrin, the MEFV product, and the C5a/IL-8 inhibitor requires further investigation.

Familial Mediterranean fever (FMF) is an inherited disease whose manifestations are acute but reversible attacks of sterile inflammation affecting synovial and serosal spaces. The FMF gene (MEFV) was recently cloned, and it codes for a protein (pyrin/marenostrin) homologous to known nuclear factors. We previously reported the deficient activity of a C5a/interleukin (IL)–8 inhibitor, a physiologic regulator of inflammatory processes, in FMF serosal and synovial fluids. We now describe the concomitant expression ofMEFV and C5a/IL-8–inhibitor activity in primary cultures of human fibroblasts. Fibroblasts grown from synovial and peritoneal tissues displayed C5a/IL-8–inhibitor activity that could be further induced with phorbol myristate acetate (PMA) and IL-1β. Very low levels of chemotactic inhibitor were evident in skin fibroblast cultures or in peritoneal and skin fibroblasts obtained from FMF patients. MEFV was expressed in peritoneal and skin fibroblasts at a lower level than in neutrophils and could be further induced by PMA and IL-1β. In the FMF cultures, the MEFV transcript carried the M694V mutation, consistent with the genetic defect found in patients with this disease. MEFV was also expressed in other cell lines that do not produce C5a/IL-8 inhibitor. These findings suggest that human primary fibroblast cultures express MEFV and produce C5a/IL-8–inhibitor activity. The interrelationship between pyrin, the MEFV product, and the C5a/IL-8 inhibitor requires further investigation.