Pretreatment before ischemia induction with polymerized human placenta hemoglobin (PolyPHb) attenuates ischemia/reperfusion injury-induced myocardial apoptosis

mPEG-icariin nanoparticles for treating myocardial ischaemia

Icariin (ICA), a major active ingredient from Chinese medicine, has unique pharmacological effects on ischaemic heart disease. However, its hydrophobic property limits its administration and leads to poor efficacy. This work aimed to change its hydrophobic property and improve the treatment efficacy. We designed a new nano-drug to increase the ICA delivery. ICA was modified with hydrophilic polyethylene glycol monomethyl ether (mPEG) by a succinic anhydride linker to form a polyethylene glycol-icariin (mPEG-ICA) polymer. The structure of this polymer was identified by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The content of ICA in the polymer was 32% as detected by ultraviolet spectrophotometry. mPEG-ICA nanoparticles, of 143.3 nm, were prepared by the dialysis method, and zeta potential was 0.439 mV by dynamic light scattering. The nanoparticles had a spherical shape on transmission electron microscopy. In media with pH 7.4 and 6.8, ICA release from mPEG-ICA nanoparticles after 72 h was about 0.78% and 64.05%, respectively, so the ICA release depended on the release media pH. On MTT and lactate dehydrogenase activity assay, mPEG-ICA nanoparticles could reduce cell damage induced by oxgen-glucose deprivation. Hoechst 33258 staining and TUNEL and AnnexinV-FITC/PI double staining showed that ICA nanoparticles could increase the activity of H9c2 cardiomyocytes under oxgen-glucose deprivation conditions by decreasing apoptosis. ICA modified by hydrophilic mPEG could improve its efficacy.

Polymerized human placenta haemoglobin attenuates myocardial injury and aortic endothelial dysfunction in a rat model of severe burns

This study was designed to investigate the effect of polymerized human placenta haemoglobin (PolyPHb) on cardiac dysfunction after severe burns. A total of 60 male Sprague-Dawley rats were randomly divided into 3 groups: Sham, Burn and Burn + PolyPHb groups. Rats were subjected to third-degree burns to 30% of total body surface area and the haemodynamics, cardiac enzyme release and aortic endothelium ultrastructure/function were measured. PolyPHb (0.5 gHb/kg) greatly improved mean arterial pressure, left ventricular developed pressure (LVDP), maximum LVDP increase and decrease rate and reduced left ventricular end-diastolic pressure as compared to the Burn group. The plasma levels of cardiac enzyme including CK-MB and troponin I were also significantly down-regulated in the Burn + PolyPHb group. In addition, PolyPHb treatment markedly restored the endothelium-dependent relaxation impaired by severe burns and pathological changes of endothelium in aorta. Therefore, our data suggest that PolyPHb can limit severe burn-induced myocardial injury, which is associated with protection of aortic endothelium.

Lipocalin-2 (NGAL) Attenuates Autophagy to Exacerbate Cardiac Apoptosis Induced by Myocardial Ischemia

Lipocalin-2 (Lcn2; also termed neutrophil gelatinase-associated lipocalin (NGAL)) levels correlate positively with heart failure (HF) yet mechanisms via which Lcn2 contributes to the pathogenesis of HF remain unclear. In this study, we used coronary artery ligation surgery to induce ischemia in wild-type (wt) mice and this induced a significant increase in myocardial Lcn2. We then compared wt and Lcn2 knockout (KO) mice and observed that wt mice showed greater ischemia-induced caspase-3 activation and DNA damage measured by TUNEL than Lcn2KO mice. Analysis of autophagy by LC3 and p62 Western blotting, LC3 immunohistochemistry and transmission electron microscopy (TEM) indicated that Lcn2 KO mice had a greater ischemia-induced increase in autophagy. Lcn2KO were protected against ischemia-induced cardiac functional abnormalities measured by echocardiography. Upon treating a cardiomyocyte cell line (h9c2) with Lcn2 and examining AMPK and ULK1 phosphorylation, LC3 and p62 by Western blot as well as tandem fluorescent RFP/GFP-LC3 puncta by immunofluorescence, MagicRed assay for lysosomal cathepsin activity and TEM we demonstrated that Lcn2 suppressed autophagic flux. Lcn2 also exacerbated hypoxia-induced cytochromc c release from mitochondria and caspase-3 activation. We generated an autophagy-deficient H9c2 cell model by overexpressing dominant-negative Atg5 and found significantly increased apoptosis after Lcn2 treatment. In summary, our data indicate that Lcn2 can suppress the beneficial cardiac autophagic response to ischemia and that this contributes to enhanced ischemia-induced cell death and cardiac dysfunction. J. Cell. Physiol. 232: 2125-2134, 2017. © 2016 Wiley Periodicals, Inc.

Pretreatment with pPolyHb attenuates H2O2-induced endothelial cell injury through inhibition of JNK/p38 MAPK pathway by upregulation of heme oxygenase-1

Polymerized porcine hemoglobin (pPolyHb) exhibits a protective effect on ischemia/reperfusion of organ grafts. A series of experiments were performed to explore the underlying cytoprotective mechanisms of pPolyHb pretreatment on H2O2-induced cell death and apoptosis. The results showed that the pretreatment augmented heme oxygenase-1 (HO-1) expression, and at the same time, decreased the phosphorylation of JNK/p38 mitogen-activated protein kinase (MAPK) and intracellular ROS generation in H2O2-treated HUVECs. Moreover, the inhibition of HO-1 expression by tin porphyrin (SnPP) abolished the protective effects of pPolyHb, which suggested that the cytoprotective effect of pPolyHb involves upregulating HO-1 and subsequently decreasing the phosphorylation of the JNK and p38 MAPK and ROS generation.

Isovolemic hemodilution with glutaraldehyde-polymerized human placenta hemoglobin (PolyPHb) attenuated rat liver ischemia/reperfusion injury

This study was to investigate whether glutaraldehyde-polymerized human placenta hemoglobin (PolyPHb) could attenuate ischemia/reperfusion (I/R)-induced liver injury. Isovolemic hemodilution of SD rats was performed by exchanging 15% total blood volume with PolyPHb. I/R was induced by left liver lobes pedicle cross-clamping for 60 min and reperfusion for 2 h. Blood pressure moderately elevated after PolyPHb infusion and returned to basal level within 10 min. The hepatic histopathological damage and the activities of liver injury markers were reduced by PolyPHb. The TUNEL staining and caspase assay indicated hepatic apoptosis was also inhibited. Therefore, our findings suggest PolyPHb can reduce liver I/R injury.

Polymerized human placenta hemoglobin given before ischemia protects rat heart from ischemia reperfusion injury

This study was to investigate whether polymerized human placenta hemoglobin (PolyPHb) given before ischemia protects in vivo rat heart function against ischemia/reperfusion (I/R) injury. Forty-five male Sprague-Dawley rats were randomly divided (n = 15 per group) into a sham group, control group (pretreatment with Lactated Ringer's solution), or PolyPHb group (pretreatment with 0.1 gHb/kg PolyPHb). Rat hearts were subjected to 30-min ischemia by occlusion of left anterior descending, followed by 2-hr reperfusion. As compared to the control group, PolyPHb preserved cardiac function and reduced cardiac troponin-I release and histopathological changes. Therefore, PolyPHb pretreatment provided a profound cardioprotective effect on the in vivo rat heart.