Application and Utility of Liposomal Neuroprotective Agents and Biomimetic Nanoparticles for the Treatment of Ischemic Stroke

Ischemic stroke is still one of the leading causes of high mortality and severe disability worldwide. Therapeutic options for ischemic stroke and subsequent cerebral ischemia/reperfusion injury remain limited due to challenges associated with drug permeability through the blood-brain barrier (BBB). Neuroprotectant delivery with nanoparticles, including liposomes, offers a promising solution to address this problem, as BBB disruption following ischemic stroke allows nanoparticles to pass through the intercellular gaps between endothelial cells. To ameliorate ischemic brain damage, a number of nanotherapeutics encapsulating neuroprotective agents, as well as surface-modified nanoparticles with specific ligands targeting the injured brain regions, have been developed. Combination therapy with nanoparticles encapsulating neuroprotectants and tissue plasminogen activator (t-PA), a globally approved thrombolytic agent, has been demonstrated to extend the narrow therapeutic time window of t-PA. In addition, the design of biomimetic drug delivery systems (DDS) employing circulating cells (e.g., leukocytes, platelets) with unique properties has recently been investigated to overcome the injured BBB, utilizing these cells’ inherent capability to penetrate the ischemic brain. Herein, we review recent findings on the application and utility of nanoparticle DDS, particularly liposomes, and various approaches to developing biomimetic DDS functionalized with cellular membranes/membrane proteins for the treatment of ischemic stroke

Possible role of immune surveillance at the initial phase of metastasis produced by B16BL6 melanoma cells

AbstractThe relationship among the real-time trafficking of lung metastatic B16BL6 cells, metastatic potential, and the injected number of the cells was examined, since the smaller the number of tumor cells injected, the more clearly the immune defense may be observed. When 1×106 or 1×105 B16BL6 cells were injected into mice via the tail vein, both numbers of cells accumulated in the lung at a similar rate: there was an approximately 10-fold difference in the number of accumulated cells between the two doses. Elimination from the lung was not dependent on the cell number but on the proportion of accumulated cells. However, the injection of 1×104 cells resulted in lung accumulation less than one-tenth of that obtained with 1×105 cell injection. Metastasis was observed when 1×105 or 1×106 B16BL6 cells were injected, but not after injection of 1×104 cells. To clarify the roles of the immune defense system at the initial phase of metastasis, we challenged macrophage-depleted mice with 1×104 tumor cells. Treatment of mice with 2-chloroadenosine prior to the tumor cell challenge cancelled the suppression of not only metastasis but also the lung accumulation. Furthermore, the administration of 2-chloroadenosine following the tumor cell challenge had little effect on the metastatic potential. These results suggest that the immune surveillance whose action was obvious at the low dose of challenged tumor cells functions strongly at the initial phase but not at the advanced stages of the metastatic process, and that macrophages play an important role in the suppression of metastasis

Possible mechanism of polycation liposome (PCL)-mediated gene transfer

AbstractA novel gene transfer system utilizing polycation liposomes (PCLs), obtained by modifying liposomes with cetyl polyethylenimine (PEI), was previously developed (Gene Ther. 7 (2002) 1148). PCLs show notable transfection efficiency with low cytotoxicity. However, the mechanism of PCL-mediated gene transfer is still unclear. In this study, we examined the intracellular trafficking of PCL–DNA complexes by using HT1080 cells, fluorescent probe-labeled materials, and confocal laser scan microscopy. We found that the PCL–DNA complexes were taken up into cells by the endosomal pathway, since both cellular uptake of the complex and gene expression were blocked by wortmannin, an inhibitor of this pathway. We also observed that the plasmid DNA and cetyl PEI complex became detached from the PCL lipids and was preferentially transferred into the nucleus in the form of the complex, whereas the PCL lipids remained in the cytoplasmic area, possibly in the endosomes. In fact, nigericin, which dissipates the pH gradient across the endosomal membrane, inhibited the detachment of lipids from the PCL–DNA complex and subsequent gene expression. Taken together, our data indicate the following mechanism for gene transfer by PCLs: PCLs effectively transfer DNA to endosomes and release cetyl PEI–DNA complexes into the cytosol. Furthermore, cetyl PEI also contributes to gene entry into the nucleus

Genetic Analysis of Cardiacβ Myosin Heavy Chain(MHC)Gene in Seven Families with Hypertrophic Cardiomyopathy in Japan

The purpose of this study was to identify the presence of either mutation or polymorphism in the cardiac β myosin heavy chain (MHC) gene of the Japanese who had familial hypertrophic cardiomyopathy (FHCM). We analyzed exons 3-25 of the cardiac MHC gene in seven unrelated Japanese families (17 affected and 10 unaffected individual with HCM), using the polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis. Our study showed that affected members of one family (proband; I.I.) had an identical pattern of aberrantly migrating band of exon 21.Similarly we found polymorphism and probable point mutation located on exon 3 of one patient with sporadic HCM (Pt;T.M.). Both proband;I. I. and Pt; T.M., developed lethal congestive heart failure with left ventricular (LV) dilatation as confirmed by autopsy. This suggest that PCR-SSCP analysis is an useful tool for clinical screening of HCM

Impact of Gender on In-hospital Mortality in Patients with Acute Myocardial Infarction in Nagasaki

Acute myocardial infarction (AMI) is one of the leading causes of death in Japan. Immediate reperfusion therapy, includingcoronary intervention, improves patient prognosis. Despite this, females are said to be more prone to poor prognosis. A regional AMI registry in Nagasaki prefecture has been instituted recently that will evaluate whether female gender might predict short-term in-hospital death. Seventeen regional AMI centers enrolled all AMI patients from September 2014 through March 2016. A propensity score (PS) was derived using logistic regression to model the probability of females as a total function of the potential confounding covariates. Two types of PS techniques were used: PS matching and PS stratification. The consistency of in-hospital death was determined between PS matched patients of both genders. Based on PS, patients were ranked and stratified into five groups for the PS stratification. Out of 996 patients, 67 (6.7%) died during hospitalization: 31 (10.4%) out of 298 females and 36 (5.2%) out of 698 males (p < 0.0025). The proportion of cardiac and non-cardiac related death was almost same between genders (25 and 6 in female, 29 and 7 in male, respectively). Among 196 PS matched patients, there was a consistency between genders regarding in-hospital deaths (McNemar test, p = 0.6698). The 717 propensity scored patients had no significant differences between genders among propensity quintiles (Cochran-Mantel-Heanszel test, p = 0.7117). We found that gender alone is not an indicator of short-term in-hospital death in acute myocardial infarction patients

Transient Increase in Zn2+ in Hippocampal CA1 Pyramidal Neurons Causes Reversible Memory Deficit

The translocation of synaptic Zn2+ to the cytosolic compartment has been studied to understand Zn2+ neurotoxicity in neurological diseases. However, it is unknown whether the moderate increase in Zn2+ in the cytosolic compartment affects memory processing in the hippocampus. In the present study, the moderate increase in cytosolic Zn2+ in the hippocampus was induced with clioquinol (CQ), a zinc ionophore. Zn2+ delivery by Zn-CQ transiently attenuated CA1 long-term potentiation (LTP) in hippocampal slices prepared 2 h after i.p. injection of Zn-CQ into rats, when intracellular Zn2+ levels was transiently increased in the CA1 pyramidal cell layer, followed by object recognition memory deficit. Object recognition memory was transiently impaired 30 min after injection of ZnCl2 into the CA1, but not after injection into the dentate gyrus that did not significantly increase intracellular Zn2+ in the granule cell layer of the dentate gyrus. Object recognition memory deficit may be linked to the preferential increase in Zn2+ and/or the preferential vulnerability to Zn2+ in CA1 pyramidal neurons. In the case of the cytosolic increase in endogenous Zn2+ in the CA1 induced by 100 mM KCl, furthermore, object recognition memory was also transiently impaired, while ameliorated by co-injection of CaEDTA to block the increase in cytosolic Zn2+. The present study indicates that the transient increase in cytosolic Zn2+ in CA1 pyramidal neurons reversibly impairs object recognition memory

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts