Heparin reduces ischemia-reperfusion injury to myocardium. This effect has been attributed to complement inhibition, but heparin also has other activities that might diminish ischemia-reperfusion. To further probe these mechanisms, we compared heparin or an o-desulfated nonanticoagulant heparin with greatly reduced anticomplement activity. When given at the time of coronary artery reperfusion in a canine model of myocardial infarction, heparin or o-desulfated heparin equally reduced neutrophil adherence to ischemic-reperfused coronary artery endothelium, influx of neutrophils into ischemic-reperfused myocardium, myocardial necrosis, and release of creatine kinase into plasma. Heparin or o-desulfated heparin also prevented dysfunction of endothelial-dependent coronary relaxation following ischemic injury. In addition, heparin and o-desulfated heparin inhibited translocation of the transcription nuclear factor-kappaB (NF-kappaB) from the cytoplasm to the nucleus in human endothelial cells and decreased NF-kappaB DNA binding in human endothelium and ischemic-reperfused rat myocardium. Thus heparin and nonanticoagulant heparin decrease ischemia-reperfusion injury by disrupting multiple levels of the inflammatory cascade, including the novel observation that heparins inhibit activation of the proinflammatory transcription factor NF-kappaB.

Adenosine (ADO) attenuates polymorphonuclear neutrophil (PMN)-mediated damage, partly by inhibiting superoxide anion (O2-.) generation and PMN adherence to the coronary artery endothelium. This study tests the hypothesis that the antineutrophil effects of ADO are mediated by A2-receptor activation. Isolated canine PMN were activated by 100 nM platelet-activating factor (PAF). Compared with untreated activated PMN (100%), ADO attenuated O2-. production (46 +/- 9% of activated PMN), which was mimicked by the A2 agonist CGS-21680 (50 +/- 6% of activated PMN), unaltered by A1-selective antagonism with KW-3902 in the presence of ADO (40 +/- 7%), but blocked by combined A1-A2 blockade with 8-p-sulfophenyl theophylline (8-SPT, 94 +/- 14%). ADO reduced adherence of fluorescent PMN to endothelial surfaces of isolated canine coronary artery segments from 174 +/- 12 to 29 +/- 9/mm2 (P < 0.01), which was unaltered by A1 antagonism (35 +/- 7/mm2) but was reversed by 8-SPT (150 +/- 11/mm2). CGS-21680 inhibited adherence (48 +/- 8/mm2), comparable to that of ADO. Canine coronary artery rings were incubated with activated PMN to induce injury to the endothelium. The concentration of drug required to elicit 50% of maximal relaxation (-log M) derived from dose-relaxation responses to acetylcholine in PMN-damaged rings was significantly (P < 0.05) less in ADO-treated (6.88 +/- 0.08) and CGS-21680-treated (7.12 +/- 0.09) rings than untreated rings (6.54 +/- 0.10). This protection with ADO was reversed by inclusion of 8-SPT (6.49 +/- 0.12) but not KW-3902 (6.96 +/- 0.07). We conclude that ADO reduces PMN-induced coronary endothelial injury by A2-receptor-mediated inhibition of O2-. generation and adherence.

We conclude that: (1) endogenous adenosine released from the myocardium during ischemia/reperfusion reduces infarct size by receptor-mediated mechanisms and (2) Ado-mediated cardioprotection is most pronounced during the early phase of reperfusion.

Oxidative stress-stimulated nuclear factor-kappa B (NF-kappa B) activation has been associated with rapid transcription of TNF-alpha and induction of apoptosis. This study tested the hypothesis that postconditioning (Postcon) reduces myocardial apoptosis and inhibits translocation of NF-kappa B and release of TNF-alpha secondary to an attenuation of oxidant generation during reperfusion. Anesthetized rats were subjected to 30 min of ischemia and 3 h of reperfusion and divided randomly to Control or Postcon (three cycles of 10-s reperfusion and 10-s reocclusion applied at the onset of reperfusion) group, respectively. Relative to Control, Postcon reduced the plasma malondialdehyde (1.21 +/- 0.08 vs. 0.8 +/- 0.06* microM/mL) and decreased the generation of superoxide radical in area at risk myocardium (dihydroethidium staining). Compared with Control, Postcon also inhibited translocation of NF-kappa B to nuclei (167% +/- 21% vs. 142% +/- 18%*), decreased the level of plasma TNF-alpha (1,994 +/- 447 vs. 667 +/- 130* pg/mL), and inhibited caspase-3 activity (0.57% +/- 0.1% vs. 0.21% +/- 0.1%*). The number of apoptotic cells (percent total nuclei) in ischemic myocardium was reduced (20% +/- 1% vs. 11% +/- 2%*), consistent with reduced appearance of DNA fragmentation. To support whether oxidant generation is important in the triggering of cytokine release and apoptosis, N-acetylcysteine (NAC), a potent antioxidant agent, was administered before ischemia and at reperfusion. Treatment with NAC inhibited superoxide radical generation and decreased plasma malondialdehyde to a comparable level to that in Postcon, concomitant with an inhibition of NF-kappa B expression (42% +/- 8%*) and reduction of release of TNF-alpha (231 +/- 72* pg/mL). Caspase-3 activity (0.33% +/- 0.1%*) and apoptotic cells (12% +/- 1%*) were also comparably reduced by NAC. These data suggest that Postcon attenuates myocardial apoptosis, reduces caspase-3 activity, and is potentially mediated by inhibiting oxidant-activated NF-kappa B-TNF-alpha signaling pathway. *P < 0.05 Postcon and NAC vs. Control.

Background-Ischemic postconditioning (PostC) is a recently described cardioprotective modality against reperfusion injury, through series of brief reflow interruptions applied at the very onset of reperfusion. It is proposed that PostC can activate a complex cellular signaling cascade, in which cell membrane receptors could serve as the upstream triggers of PostC. However, the exact subtypes of such receptors remain controversial or uninvestigated. To this context, the purpose of present study was to determine the definitive role of adenosine A 1 and bradykinin B 1 and B 2 receptors in PostC.

Women with functional ovaries have a lower cardiovascular risk than men and postmenopausal women. However, oestrogen replacement therapy remains controversial. This study examined the effect of ovarian hormone deficiency and oestrogen replacement on ventricular myocyte contractile function and expression of β-adrenoceptors (β-ARs). Female Sprague-Dawley rats were subjected to bilateral ovariectomy (OVX) or sham operation (Sham). A subgroup of OVX rats received oestrogen (E 2 ) replacement (40 μg kg −1 day −1 ) for 4 weeks. Cardiomyocyte shortening was evaluated in basal conditions and in the presence of isoprenaline (ISO). The expression of β-ARs was assessed by Western blotting. The presence of lactate dehydrogenase (LDH) activity in the coronary effluent was determined. Ovariectomy promoted body weight gain associated with reduced serum E 2 and uterine weight, all of which were abolished by treatment with E 2 . Ovariectomy increased the amplitude of both basal and ISO-stimulated contractions, increased LDH release, upregulated β 1 -AR expression and downregulated β 2 -AR expression, all of which were restored by treatment with E 2 . A β 1 -AR antagonist, CGP20712A, but not a β 2 -AR antagonist, ICI118,551, significantly decreased the amplitude of ventricular myocyte shortening. Oestrogen decreased cardiomyocyte contraction and the expression of β 1 -AR, and increased expression of β 2 -AR, and all these effects were abolished by the E 2 receptor antagonist, ICI182,780. These data suggest that oestrogen plays a cardioprotective role in female rat hearts subjected to ischaemia-reperfusion injury, and the effects of oestrogen are associated with decreased cardiomyocyte contraction and expression of β 1 -AR, and increased expression of β 2 -AR.

Purpose: The study aims to retrospectively investigate the efficacy and safety of sorafenib combined with transarterial chemoembolization (TACE) (TACE+Sor) vs. TACE combined with sorafenib plus immune checkpoint inhibitors (TACE+Sor+ICIs) in treating intermediate and advanced TACE-refractory hepatocellular carcinoma (HCC).Materials and Methods: This study was approved by the ethics committee of Lisui Hospital, Zhejiang University, China. From January 2016 to June 2020, 51 eligible patients with intermediate or advanced TACE-refractory HCC received TACE+Sor (n = 29) or TACE+Sor+ICIs (n = 22). The differences in tumor response, adverse events (AEs), progression-free survival (PFS), and overall survival (OS) were compared between the two groups. Factors affecting PFS and OS were determined by Cox regression.Results: The disease control rate was higher in the TACE+Sor+ICIs group than in the TACE+Sor group (81.82 vs. 55.17%, P = 0.046). Compared with the TACE+Sor group, PFS and OS were prolonged in the TACE+Sor+ICIs group (median PFS: 16.26 vs. 7.30 months, P &lt; 0.001; median OS: 23.3 vs. 13.8 months, P = 0.012). Multivariate analysis showed that BCLC stage, alpha-fetoprotein and treatment were independent factors of PFS; BCLC, Child-Pugh class, ablation after disease progression and treatment were independent predictive factors of OS. Four patients in the TACE+Sor+ICIs group and three patients in the TACE+Sor group suffered from dose reduction or interruption (18.18 vs. 10.34%, P = 0.421). The incidence of ICI-related AEs in the TACE+Sor+ICIs group was well-controlled.Conclusion: The therapeutic schedule of TACE+Sor+ICIs demonstrated efficacy and safety in intermediate and advanced TACE-refractory HCC.

Abstract:Neutrophils are pivotal in the pathogenesis of reperfusion injury leading to myocardial infarction.