Polymeric Iron Chelators Enhancing Pro-Oxidant Antitumor Efficacy of Vitamin C by Inhibiting the Extracellular Fenton Reaction.

Intravenously injected high-dose vitamin C (VC) induces extracellular H2O2, which can penetrate into the tumor cells and suppress tumor growth. However, extracellular labile iron ions in the tumor decompose H2O2 via the Fenton reaction, limiting the therapeutic effect. In this regard, we recently developed a polymeric iron chelator that can inactivate the intratumoral labile iron ions. Here, we examined the effect of our polymeric iron chelator on the high-dose VC therapy in in vitro and in vivo. In the in vitro study, the polymeric iron chelator could inactivate the extracellular labile iron ions and prevent the unfavorable decomposition of VC-induced H2O2, augmenting pro-oxidative damage to DNA and inducing apoptosis in cultured cancer cells. Even in the in vivo study, the polymeric iron chelator significantly improved the antitumor effect of VC in subcutaneous DLD-1 and CT26 tumors in mice, while conventional iron chelators could not. This work indicates the importance of modulating tumor-associated iron ions in the high-dose VC therapy and should contribute to a better understanding of its mechanism.

Synthesis of near-infrared absorbing triangular Au nanoplates using biomineralisation peptides.

Triangular Au nanoplates (TrAuNPls) possessing strong plasmonic properties can be used as photothermal agents in cancer therapy. However, the controlled preparation of such morphologies typically requires harsh synthetic conditions. Biomolecules offer an alternative route to developing biocompatible synthetic protocols. In particular, peptides offer a novel route for inorganic synthesis under ambient conditions. Herein, using the previously isolated peptide, ASHQWAWKWE, for Au nanoparticle (AuNP) synthesis, the conditions for preparing TrAuNPls via a one-pot synthetic process of mixing HAuCl4 and peptides at room temperature were investigated to effectively obtain particles possessing near-infrared absorbance for non-invasive optical diagnosis and phototherapy. By adjusting the peptide concentration, the size and property of TrAuNPls were controlled under neutral pH conditions. The synthesised particles showed potential as photothermal therapeutic agents in vitro. In addition, peptide characterisation using B3 derivatives revealed the importance of the third amino acid histidine in morphological regulation and potential circular Au nanoplates (AuNPl) synthesis with ASEQWAWKWE and ASAQWAWKWE peptides. These findings provide not only an easy and green synthetic method for TrAuNPls and circular AuNPls, but also some insight to help elucidate the regulation of peptide-based nanoparticle synthesis for use in cancer therapy. STATEMENT OF SIGNIFICANCE: Biological molecules have received increasing attention as a vehicle to synthesise inorganic materials with specific properties under ambient conditions; particularly, short peptides have the potential to control the synthesis of nanoscale materials with tailored functions. Here, the application of a previously isolated peptide was assessed in synthesising Au nanoparticles containing decahedral and triangular nanoplates with near-infrared absorbance. The size and absorbance peaks of the triangular nanoplates observed were peptide concentration-dependent. In addition, these fine-tuned triangular nanoplates exhibited potential as a phototherapeutic agent. Moreover, the peptide derivatives indicated the possibility of synthesising circular nanoplates. These findings may offer insight into development of new techniques for synthesising functional nanoparticles having biological applications using non-toxic molecules under mild conditions stituted in the original B3 peptide is underlined.

Asymptomatic Cerebral Infarction During Catheter Ablation for Atrial Fibrillation: Comparing Uninterrupted Rivaroxaban and Warfarin (ASCERTAIN).

OBJECTIVES: This randomized study compared uninterrupted rivaroxaban therapy with warfarin therapy as prophylaxis against catheter ablation (CA)-induced asymptomatic cerebral infarction (ACI) and identified the risk factors of rivaroxaban. BACKGROUND: The reported incidence of ACI during CA for atrial fibrillation (AF) remains at 10% to 30%, and periprocedural oral anticoagulation could affect this incidence. METHODS: Patients with nonvalvular AF undergoing radiofrequency CA were randomly assigned to receive either uninterrupted rivaroxaban or warfarin as periprocedural anticoagulation therapy. CA was performed after at least 1 month of adequate anticoagulation. Cerebral magnetic resonance imaging (MRI) was performed within 2 weeks before and 1 day after CA to detect ACI. RESULTS: A total 132 patients were enrolled; 127 (median: 60.0 years of age; 83.5% males; 64.6% incidence of paroxysmal AF) complied with the study protocol and were analyzed; 64 patients received rivaroxaban, and 63 patients received warfarin. The rates of CA-induced ACI in the rivaroxaban group (15.6% [10 of 64 patients]) were similar to those in the warfarin group (15.9% [10 of 63 patients]; p = 1.000). No thromboembolic events developed; no differences in major or nonmajor bleeding rates were observed between the 2 drug groups (3.1% vs. 1.6%, respectively, or 18.8% vs. 19.0%, respectively). Multiple regression analysis indicated that the presence of deep and subcortical white matter hyperintensity (p = 0.002; odds ratio [OR]: 5.323) and the frequency of cardioversions (p = 0.016; OR: 1.250) were associated with the incidence of ACI. CONCLUSIONS: No notable differences were found between the incidence of CA-induced ACI in the rivaroxaban group and that in the warfarin group in this randomized study.

In vivo evaluation of neutron capture therapy effectivity using calcium phosphate-based nanoparticles as Gd-DTPA delivery agent.

PURPOSE: A more immediate impact for therapeutic approaches of current clinical research efforts is of major interest, which might be obtained by developing a noninvasive radiation dose-escalation strategy, and neutron capture therapy represents one such novel approach. Furthermore, some recent researches on neutron capture therapy have focused on using gadolinium as an alternative or complementary for currently used boron, taking into account several advantages that gadolinium offers. Therefore, in this study, we carried out feasibility evaluation for both single and multiple injections of gadolinium-based MRI contrast agent incorporated in calcium phosphate nanoparticles as neutron capture therapy agent. METHODS: In vivo evaluation was performed on colon carcinoma Col-26 tumor-bearing mice irradiated at nuclear reactor facility of Kyoto University Research Reactor Institute with average neutron fluence of 1.8 × 10(12) n/cm(2). Antitumor effectivity was evaluated based on tumor growth suppression assessed until 27 days after neutron irradiation, followed by histopathological analysis on tumor slice. RESULTS: The experimental results showed that the tumor growth of irradiated mice injected beforehand with Gd-DTPA-incorporating calcium phosphate-based nanoparticles was suppressed up to four times higher compared to the non-treated group, supported by the results of histopathological analysis. CONCLUSION: The results of antitumor effectivity observed on tumor-bearing mice after neutron irradiation indicated possible effectivity of gadolinium-based neutron capture therapy treatment.

Anatomical characteristics of the left atrial appendage in cardiogenic stroke with low CHADS2 scores.

BACKGROUND: Strokes develop even in patients with low CHADS2 scores, and the left atrial appendage (LAA) is the embolic source 90% of the time. We focused on the LAA morphology as a new predictor of strokes. OBJECTIVE: To clarify the anatomical characteristics of the LAA for risk stratification of strokes in patients with nonvalvular atrial fibrillation (AF) who have low CHADS2 scores. METHODS: Among 80 patients who underwent catheter ablation of AF with contrast-enhanced computed tomography, the LAA characteristics were compared between 30 patients with histories of strokes and 50 age-matched controls. The LAA anatomy was classified into 4 types--"cactus," "cauliflower," "chicken wing," and "windsock"--discriminated by the computed tomography measurements of the length, angle, and number of lobes of the LAA. RESULTS: The average CHADS2 score did not differ significantly between patients with stroke and controls (0.8 ± 0.8 vs 0.6 ± 0.7; P = .277). Eight (26.7%) patients with stroke had CHA2DS2-VASc scores of 0. The left atrial size, LAA flow velocity, left ventricular function, and serum brain natriuretic peptide level were also unable to predict strokes. However, a "cauliflower" LAA, defined as a main lobe of less than 4 cm long without forked lobes, was significantly more common in patients with stroke (odds ratio 3.857; 95% confidence interval 1.482-10.037; P = .005). The CHA2DS2-VASc score-adjusted logistic regression analysis revealed the cauliflower LAA as an independent predictor of a stroke (odds ratio 3.355; 95% confidence interval 1.243-9.055; P = .017). CONCLUSIONS: The LAA anatomy might be useful for predicting strokes in patients with nonvalvular AF who have low CHADS2 scores.

Transcription factor YY1 contributes to tumor growth by stabilizing hypoxia factor HIF-1α in a p53-independent manner.

In response to hypoxic stress, hypoxia-inducible factor (HIF)-1α is a critical transcription factor regulating fundamental cellular processes, and its elevated expression level and activity are associated with poor outcomes in most malignancies. The transcription factor Yin Yang 1 (YY1) is an important negative regulator of the tumor suppressor factor p53. However, the role of YY1 under tumor hypoxic condition is poorly understood. Herein, we show that inhibition of YY1 reduced the accumulation of HIF-1α and its activity under hypoxic condition, and consequently downregulated the expression of HIF-1α target genes. Interestingly, our results revealed that the downregulation of HIF-1α by inhibiting YY1 is p53-independent. Functionally, the in vivo experiments revealed that inhibition of YY1 significantly suppressed growth of metastatic cancer cells and lung colonization and also attenuated angiogenesis in a p53-null tumor. Collectively, our findings unraveled a novel mechanism by which YY1 inhibition disrupts hypoxia-stimulated HIF-1α stabilization in a p53-independent manner. Therefore, YY1 inhibition could be considered as a potential tumor therapeutic strategy to give consistent clinical outcomes independent of p53 status.

Three-dimensional imaging and mapping of the right and left phrenic nerves: relevance to interventional cardiovascular therapy.

AIMS: Phrenic nerves (PNs) can be damaged during interventional cardiovascular therapy because of the nerves' proximity to the heart. This study aimed to analyse the anatomy of the PN by performing three-dimensional (3-D) imaging and pace mapping. METHODS AND RESULTS: Forty consecutive patients with atrial fibrillation referred for catheter ablation were enrolled in this study and underwent preoperative cardiovascular computed tomography (CT). In 10 patients with sinus rhythm during tomography, 3-D images of the right and left pericardiophrenic bundles (PBs), consisting of the ipsilateral PN and accompanying vessels, were reconstructed from the CT data. During the electrophysiological study, PN pace mapping was performed from both atria. The course of the PBs generated by CT imaging and the PN pace map generated by the 3-D mapping system were compared. By electrical pacing, the PNs were captured in 40 individuals (100%) from the superior vena cava and the right atrium, and in 17 patients (43%) from the left atrial appendage. Clear 3-D images of PBs were reconstructed in all cases in which CT-reconstruction was performed. The distance between the locations of the right PB generated by CT imaging and those of the right PN-capture sites in the right-sided heart on the mapping system was 8.7 ± 5.8 mm. CONCLUSIONS: The 3-D routes of the bilateral PNs passing near the heart were verified by pace mapping. The preoperatively reconstructed 3-D course of the PB succeeded in locating the PN, which may facilitate the comprehension of PN anatomy to avoid its injury during interventional cardiovascular therapy.

Gelatin hydrogel microspheres enable pinpoint delivery of basic fibroblast growth factor for the development of functional collateral vessels.

BACKGROUND: Various growth factors promote collateral vessel development and are regarded as promising for the treatment of vascular occlusive diseases. However, an efficacious delivery system for them has yet to be established. We devised a strategy to augment functional collateral vessels by using acidic gelatin hydrogel microspheres (AGHMs) incorporating basic fibroblast growth factor (bFGF). The aim of the present study was to investigate the hypothesis that by intra-arterial (IA) administration of bFGF-impregnated AGHMs, bFGF could be delivered from AGHMs trapped in distal small-diameter vessels and thereby induce functional collateral vessels with an assured blood supply through the process of arteriogenesis. METHODS AND RESULTS: Various sizes of AGHMs (3 mg) incorporating 125I-labeled bFGF were injected into the left internal iliac artery of a rabbit model of hindlimb ischemia. Less than 50% of radioactivity accumulated in the ischemic hindlimb after injection of AGHMs that were 10 mum in diameter, whereas approximately 80% of radioactivity was counted in the ischemic limb after administration of 29- or 59-microm-diameter AGHMs. Calf blood pressure ratio and the ratio of regional blood flow of the bilateral hindlimbs immediately before and after IA administration of 29-microm-diameter AGHMs showed no significant change. Then we evaluated the function of the developed collateral vessels 28 days after IA administration of bFGF-impregnated, 29-microm-diameter AGHMs. IA administration of bFGF-impregnated AGHMs induced marked collateral vessel improvement compared with IA administration of phosphate buffered saline-treated AGHMs and intramuscular administration of bFGF-impregnated AGHMs. CONCLUSIONS: IA administration of bFGF-impregnated, 29-microm-diameter AGHMs strongly induced functional collateral vessels without worsening ischemia, indicating the possible therapeutic usefulness of this approach.

Lactose-conjugated polyion complex micelles incorporating plasmid DNA as a targetable gene vector system: their preparation and gene transfecting efficiency against cultured HepG2 cells.

alpha-Lactosyl-poly(ethylene glycol)-poly(2-(dimethylamino)ethyl methacrylate) block copolymer (lactose-PEG-PAMA) was synthesized to construct a PIC micellar-type gene vector potentially useful for selective transfection of hepatic cells. Lactose-PEG-PAMA spontaneously formed a polyion complex (PIC) micelle with plasmid DNA (pDNA) encoding luciferase (pGL3-Luc) in aqueous solution without any precipitate formation. The lactosylated PIC micelle thus prepared achieved substantially higher transfection efficiency compared to the control PIC micelle without lactose moieties against HepG2 cells possessing asialoglycoprotein (ASGP) receptors recognizing the beta-d-galactose residue. This pronounced transfection efficacy of the lactosylated PIC micelle was inhibited by the addition of excess asialofetuin (ASF), a natural ligand against the ASGP receptor, indicating ASGP receptor-mediated endocytosis to be a major route of the cellular uptake of the lactosylated micelles. Notably, the lactosylated PIC micelle revealed enhanced transfection compared to the control PIC micelle at a lower dose of pDNA, demonstrating the feasibility of using the ligand-conjugated PIC micellar vector for gene delivery to targeted cells.

Polyion complex micelles entrapping cationic dendrimer porphyrin: effective photosensitizer for photodynamic therapy of cancer.

Photosensitizers play a crucial role in the photodynamic therapy (PDT) of cancer. In this study, a third-generation aryl ether dendrimer porphyrin with 32 primary amine groups on the periphery, [NH2CH2CH2NHCO]32DPZn, and pH-sensitive, polyion complex micelles (PIC) composed of the porphyrin dendrimer and PEG-b-poly(aspartic acid), were evaluated as new photosensitizers (PSs) for PDT in the Lewis Lung Carcinoma (LLC) cell line. The preliminary photophysical characteristics of [NH2CH2CH2NHCO]32DPZn and the corresponding micelles were investigated. Electrostatic assembly resulted in a red-shift of the Soret peak of the porphyrin core and the enhanced fluorescence. Compared to the dendrimer porphyrin [NH2CH2CH2NHCO]32DPZn, relatively low cellular uptake of dendrimer porphyrin [NH2CH2CH2NHCO]32DPZn incorporated in the PIC micelle was observed, yet the latter exhibited enhanced photodynamic efficacy on the LLC cell line. Importantly, the use of PIC micelles as a delivery system reduced the dark toxicity of the cationic dendrimer porphyrin, probably due to the biocompatible PEG shell of the micelles.