Background— Although treatment with immunosuppressive agents has contributed to overcoming acute rejection and improving the midterm survival of transplanted hearts, cardiac allograft vasculopathy (CAV) has remained the main cause of primary graft failure. Recent approaches have shown that hepatocyte growth factor (HGF) exhibits cardiotrophic functions. We therefore addressed whether HGF would regulate acute and chronic rejection in cardiac transplantation. Methods and Results— We used a murine heterotopic cardiac transplantation model between fully incompatible strains and administered 500 μg · kg −1 · d −1 HGF during the initial 14 days after transplantation. The HGF-treated allografts showed significantly prolonged survival (42.3±4.1 days, P <0.001) compared with the controls (11.1±0.6 days), with tolerance induction in 47.4%. Histopathologically, the number of infiltrating cells was significantly decreased and myocardial necrosis was less prominent with a reduction of apoptosis in the allografts by HGF treatment during acute rejection. In the long-term surviving allografts, HGF significantly inhibited the development of CAV and interstitial fibrosis. With respect to intragraft cytokine mRNA expression, HGF treatment reduced the early expression of interferon-γ and enhanced the expression of transforming growth factor-β1 during the acute phase and of interleukin-10 continuously through the acute phase to the chronic phase. Conclusions— Our findings demonstrate that HGF can prolong the survival of allografts by its cardioprotective and immunomodulative potencies. Thus, HGF administration may constitute a new therapeutic approach to preventing cardiac graft failure that has not been overcome by conventional immunosuppressive agents.

Objective: Acute type A aortic dissection during pregnancy can be fatal to both the mother and the fetus. The goal of the present study was to characterize the prevalence, treatment and outcomes of this dangerous condition in an effort to determine optimal management. Methods:A retrospective study was conducted using data from four Marfan patients with acute type A aortic dissection during pregnancy at our institution between 1991 and 2003. Results:The mean gestational period at the time of operative repair was 31 weeks, with a range of 26-34 weeks, and the aortic root diameter ranged from 35 to 85 mm. Two of the four patients underwent a combined operation with caesarean section followed by aortic repair. One patient underwent operative aortic repair following spontaneous delivery. The final patient underwent aortic repair with the fetus remaining in situ.Median sternotomy and cardio-pulmonary bypass were established via the femoral artery with direct right atria drainage and left atrial venting in all patients. Composite graft replacement combined with re-implantation of the coronary artery and aortic valve replacement were performed in three patients, and aortic valve replacement with coronary artery bypass grafting of the right coronary artery was performed in one patient. Three of four patients underwent aortic arch repair utilizing antegrade cerebral perfusion and deep hypothermia with total circulatory arrest. The patent that underwent operative correction with the fetus remaining in situ experienced fetal demise with miscarriage just after cardiac surgery, and the patient died four days later secondary to disseminated intravascular coagulation and multi-organ failure. The remaining three cases recovered uneventfully, and the mothers and babies were discharged in good condition. Conclusions:Based on these data, we advocate Caesarean section with concomitant aortic repair for patients with Marfan syndrome and acute type A aortic dissection during pregnancy. Minimization of deep hypothermic circulatory arrest time is also recommended for cases in which the fetus remains in situ.

Whole‐cell currents were recorded from guinea‐pig atrial myocytes using the patch‐clamp technique under conditions designed to block K+ channels, Ca2+ channels and electrogenic transporters. Exposure of atrial myocytes to the hyposmotic external solution (Na+ reduction to about 70% of control) resulted in hyposmotic cell swelling which was associated with activation of an outwardly rectifying Cl− current (ICl,swell). Whereas the activation of ICl,swell was not significantly affected by replacement of ATP in the pipette solution with the non‐hydrolysable ATP analogue 5′‐adenylyl‐imidodiphosphate (AMP‐PNP), its activation was greatly reduced in cells dialysed with an ATP‐free pipette solution, thus indicating that the activation process of ICl,swell requires the presence of intra‐cellular ATP, but not its hydrolysis. Bath application of glibenclamide produced a concentration‐dependent block of ICl,swell with a half‐maximal inhibitory concentration (IC50) of 60.0 μm and a Hill coefficient of 2.1. The maximal effect (100% inhibition) was obtained with 500 μm glibenclamide. The steady‐state inhibition showed little voltage dependence, while glibenclamide at concentrations of more than 100 μm inhibited the outward ICl,swell more rapidly than the inward ICl,swell. The glibenclamide inhibition was fully reversible after removal of the drug, even when a maximal effect (full inhibition) was achieved at a high drug concentration (500 μm). These results show that (i) glibenclamide is one of the most potent inhibitors of guinea‐pig atrial ICl,swell and (ii) atrial ICl,swell and the cystic fibrosis transmembrane conductance regulator (CFTR) Cl− currents are almost equally sensitive to inhibition by glibenclamide.

1. We studied the effects of P2-purinoceptor stimulation on the delayed rectifier K+ current (IK) 3. External ADP also enhanced IK in a dose-dependent manner with a K% of 3-65 /UM, whereas adenosine (100 /,M) failed to evoke this response. Theophylline (500 ,tM), a blocker of the P1-purinoceptor, did not antagonize the stimulating action of ATP on IK. These results indicate that IK was enhanced via P2-purinoceptors. 4. External ATP or ADP did not produce a significant change in the current kinetics of IK.

1. Whole-cell voltage clamp and cell-attached patch-clamp techniques were applied to single atrial myocytes enzymatically dissociated from adult guinea-pig hearts.2. In whole-cell clamp conditions, external application of ATP activated the muscarinic K+ (KACh) current, identified by its inward rectification, its reversal potential near the calculated K+ equilibrium potential (EK) and its relaxation properties during step changes of whole-cell membrane potential. Theophylline, an antagonist for P1-purinoceptors, did not affect the action of ATP on the KAch current, indicating that the response was evoked through P2-purinoceptors. 3. ' The concentration-response relationship for ATP was well described by a Hill equation with a half-maximal concentration of 1P84 /M and a Hill coefficient of 0 94. ATP (100 uM) produced a maximal increase of the KACh current to 10-92 1uA suF-, which corresponds to 44*9 and 80 9 % of the maximal increases evoked by ACh (10 #M) and adenosine (100 #M), respectively. 4. The ATP-induced KAch current gradually declined to a steady level despite the continuous presence of ATP (desensitization). Recovery from the desensitization was relatively rapid with a half-time of approximately 1-5 min.5. The activation of KACh current by ATP was completely abolished by pre-incubating myocytes with pertussis toxin (PTX, 5 jug ml-'), indicating that P2-purinoceptors are coupled to PTX-sensitive G proteins to activate the KACh channel.6. In the cell-attached patch recording, ATP (5/uM) applied to the pipette solution enhanced the activity of a channel with single-channel conductance of 52-7 + 0o9 pS (mean + S.E.M., n = 10), reversal potential near EK and mean open time of 1 1 + 0 1 ms. These conductance and kinetic properties are identical to those of the KAch channel in the heart.In contrast, ATP applied to the bath solution did not significantly affect the basal activity of KACh channel openings. These observations suggest that the mechanism coupling the P2-purinoceptor to the activation of the KACh channel involves membrane-delimited component(s) rather than soluble second messenger(s).7. These results strongly suggest a direct coupling of the P2-purinoceptor to the KACh channel through PTX-sensitive G proteins, analogous to the coupling mechanism of the muscarinic ACh receptor and P,-purinoceptor to this channel.

2,3-Butanedione monoxime (BDM) is widely believed to act as a chemical phosphatase. We therefore examined the effects of BDM on the cystic fibrosis transmembrane regulator (CFTR) Cl Ϫ channel, which is regulated by phosphorylation in a complex manner. In guinea pig ventricular myocytes, forskolinactivated whole-cell CFTR currents responded biphasically to external 20 mM BDM: a rapid ϳ2-fold current activation was followed by a slower ( ϳ20 s) inhibition (to ϳ20% of control). The inhibitory response was abolished by intracellular dialysis with the phosphatase inhibitor microcystin, suggesting involvement of endogenous phosphatases. The BDM-induced activation was studied further in Xenopus laevis oocytes expressing human epithelial CFTR. The concentration for half-maximal BDM activation (K 0.5 ) was state-dependent, ϳ2 mM for highly and ϳ20 mM for partially phosphorylated channels, suggesting a modulated receptor mechanism. Because BDM modulates many different membrane proteins with similar K 0.5 values, we tested whether BDM could alter protein function by altering lipid bilayer properties rather than by direct BDM-protein interactions. Using gramicidin channels of different lengths (different channel-bilayer hydrophobic mismatch) as reporters of bilayer stiffness, we found that BDM increases channel appearance rates and lifetimes (reduces bilayer stiffness). At 20 mM BDM, the appearance rates increase ϳ4-fold (for the longer, 15 residues/monomer, channels) to ϳ10-fold (for the shorter, 13 residues/monomer channels); the lifetimes increase ϳ50% independently of channel length. BDM thus reduces the energetic cost of bilayer deformation, an effect that may underlie the effects of BDM on CFTR and other membrane proteins; the state-dependent changes in K 0.5 are consistent with such a bilayer-mediated mechanism.

Inhibiting the activity of the neutrophil elastase may attenuate the postoperative respiratory complications of patients with AAD.

A 41-year-old man was diagnosed with anomalous origin of the right coronary artery from the left sinus of Valsalva with a slit ostium. Surgery was offered to the patient in view of his young age and the unpredictable natural history of the disease. Direct reimplantation of the right coronary artery to the right sinus was performed under cardiopulmonary bypass. The patient recovered uneventfully. Postoperative coronary angiography showed good patency of the reconstructed artery while exercise thallium scintigraphy showed no ischemic change. Excellent longevity of the directly reimplanted coronary artery can be expected.