Motoi Okada

Prostaglandin I2 promotes recruitment of endothelial progenitor cells and limits vascular remodeling

Objective—Endothelial progenitor cells (EPCs) play an important role in the self-healing of a vascular injury by participating in the reendothelialization that limits vascular remodeling. We evaluated whether prostaglandin I2 plays a role in the regulation of the function of EPCs to limit vascular remodeling. Methods and Results—EPCs (Lin−cKit+Flk-1+ cells) were isolated from the bone marrow (BM) of wild-type (WT) mice or mice lacking the prostaglandin I2 receptor IP (IP−/− mice). Reverse transcription–polymerase chain reaction analysis showed that EPCs among BM cells specifically express IP. The cellular properties of EPCs, adhesion, migration, and proliferation on fibronectin were significantly attenuated in IP-deficient EPCs compared with WT EPCs. In contrast, IP agonists facilitated these functions in WT EPCs, but not in IP-deficient EPCs. The specific deletion of IP in BM cells, which was performed by transplanting BM cells of IP−/− mice to WT mice, accelerated wire injury–mediated neointimal hyperplasia in the femoral artery. Notably, transfused WT EPCs, but not IP-deficient EPCs, were recruited to the injured vessels, participated in reendothelialization, and efficiently rescued the accelerated vascular remodeling. Conclusion—These findings clearly indicate that the prostaglandin I2-IP system is essential for EPCs to accomplish their function and plays a critical role in the regulation of vascular remodeling.

Thermal Treatment Attenuates Neointimal Thickening With Enhanced Expression of Heat-Shock Protein 72 and Suppression of Oxidative Stress

Background—The beneficial effects of thermal therapy have been reported in several cardiovascular diseases. However, it is unknown whether the thermal treatment has some beneficial roles against the development of atherosclerosis. Methods and Results—The inflammatory arterial lesion was introduced by placement of a polyethylene cuff on femoral arteries of male Sprague-Dawley rats for 4 weeks. Thermal-treated group underwent daily bathing in 41°C hot water for 15 minutes. Neointimal thickening along with immunohistochemical expression of heat-shock proteins (HSPs), monocyte chemoattractant protein-1 (MCP-1), and NADPH oxidase were compared with those of a thermally untreated (Control) group. Morphometric analysis demonstrated a significant suppression of neointimal thickening in thermal-treated group compared with the Control group (intimal/medial area ratios, 0.01±0.01 versus 0.31±0.04, P <0.01). Expression of MCP-1 and infiltration of ED-positive cells were enhanced in the adventitial layer of Control. More importantly, expression of HSP72 in media was enhanced by thermal treatment. Expression of p22-phox, the major membrane subunit of NADPH oxidase, and MCP-1 was augmented in cuff-injured adventitia of the Control but not the thermal-treated groups. Conclusions—Thermal treatment significantly attenuated infiltration of inflammatory cells in adventitia and suppressed neointimal thickening in cuff-injured arteries with the enhancement of HSP72 expression and suppression of oxidative stress.

Cardiac stem cells with electrical stimulation improve ischaemic heart function through regulation of connective tissue growth factor and miR-378

AIMS In this study, we investigated whether pre-conditioning (PC) by electrical stimulation (EleS) induces cytoprotective effect on cardiac stem cells (CSCs) and determined its underlying molecular mechanisms. METHODS AND RESULTS Sca-1(+) CSCs were isolated from male C57BL6 mice (12 weeks) hearts. PC of CSCs with EleS ((EleS)CSCs) was carried out for 3 h at 1.5 V followed by exposure to 300 µM H2O2 for 5 h. Cytoprotective effects and cell adhesion ability were significantly increased by EleS as evaluated by transferase-mediated dUTP nick-end labelling (TUNEL), lactate dehydrogenase (LDH) release assay, and adhesion assay. EleS increased phosphorylation of AKT, focal adhesion kinase (FAK), and glycogen synthase kinase (GSK3β), as well as decreased caspase-3 cleavage. Interestingly, inhibition of AKT or FAK abolished the pro-survival effects of EleS. We found that connective tissue growth factor (Ctgf) was responsible for EleS-induced CSC survival and adhesion.The survival rate of (EleS)CSCs after transplantation in the infarcted myocardium was significantly increased together with improvement in cardiac function. Importantly, knockdown of Ctgf abolished EleS-induced cytoprotective effects and recovery of cardiac function. Furthermore, we identified miR-378 as a potential Ctgf regulator in (EleS)CSCs. CONCLUSION EleS enhanced CSC survival in vitro and in vivo as well as functional recovery of the ischaemic heart through an AKT/FAK/CTGF signalling pathway. It is suggested that Ctgf and miR-378 are novel therapeutic targets for stem cell-based therapy.

Impaired Glutathione Redox System Paradoxically Suppresses Angiotensin II-Induced Vascular Remodeling

Background Angiotensin II (AII) plays a central role in vascular remodeling via oxidative stress. However, the interaction between AII and reduced glutathione (GSH) redox status in cardiovascular remodeling remains unknown. Methods In vivo: The cuff-induced vascular injury model was applied to Sprague Dawley rats. Then we administered saline or a GSH inhibitor, buthionine sulfoximine (BSO, 30 mmol/L in drinking water) for a week, subsequently administered 4 more weeks by osmotic pump with saline or AII (200 ng/kg/minute) to the rats. In vitro: Incorporation of bromodeoxyuridine (BrdU) was measured to determine DNA synthesis in cultured rat vascular smooth muscle cells (VSMCs). Results BSO reduced whole blood GSH levels. Systolic blood pressure was increased up to 215±4 mmHg by AII at 4 weeks (p<0.01), which was not affected by BSO. Superoxide production in vascular wall was increased by AII and BSO alone, and was markedly enhanced by AII+BSO. The left ventricular weight to body weight ratio was significantly increased in AII and AII+BSO as compared to controls (2.52±0.08, 2.50±0.09 and 2.10±0.07 mg/g respectively, p<0.05). Surprisingly, the co-treatment of BSO totally abolished these morphological changes. Although the vascular circumferential wall stress was well compensated in AII, significantly increased in AII+BSO. The anti-single-stranded DNA staining revealed increasing apoptotic cells in the neointima of injured arteries in BSO groups. BrdU incorporation in cultured VSMCs with AII was increased dose-dependently. Furthermore it was totally abolished by BSO and was reversed by GSH monoethyl ester. Conclusions We demonstrated that a vast oxidative stress in impaired GSH redox system totally abolished AII-induced vascular, not cardiac remodeling via enhancement of apoptosis in the neointima and suppression of cell growth in the media. The drastic suppression of remodeling may result in fragile vasculature intolerable to mechanical stress by AII.

Adult T-cell leukemia with invasion by malignant cells of both parotid glands diagnosed by an Ga-67 imaging : A case report

Adult T-cell leukemia (ATL) shows several initial symptoms such as lymphadenopathy. Although oral cavity dryness is uncommon as an initial symptom of ATL, the authors encountered a case of a 74-year-old man patient who complained of this initial symptom. Routine examinations and clinical course indicated that he was suffering from ATL. Further examination such as Ga-67 citrate scintigraphy and a postmortem study showed that this symptom had been induced by the invasion by ATL cells of the bilateral parotid glands. Therefore, ATL should be considered in patients with an initial symptom of oral cavity dryness and enlargement of the bilateral parotid glands.

Cerebral Microbleeds Remain for Nine Years: A Prospective Study with Yearly Magnetic Resonance Imaging

BACKGROUND Cerebral microbleeds (CMBs) are refined neuroimaging findings detected on T2*-weighted gradient echo (GRE) magnetic resonance imaging (MRI) and are widely accepted as an important marker of the vulnerability of cerebral small vessels. It is necessary to further clarify the natural history of CMBs by a longitudinal study. This study aimed to reveal the natural history of CMBs and find a better way to track CMBs by a prospective long-term observation. METHODS We performed yearly brain MRI assessments for 7 or more years in 8 nonvalvular atrial fibrillation Japanese outpatients with CMBs detected in the baseline MRI. We began to use a 3.0T MRI scanner from 2012 as well. RESULTS We followed up 3 patients for 9 years, 2 for 8 years, and 3 for 7 years. In all patients, the CMBs at baseline did not disappear during the follow-up period. Importantly, the CMB in 1 patient seemed to disappear during the sixth imaging using 1.5T T2*-weighted GRE but was detected again during the seventh imaging with 3.0T susceptibility weighted imaging and ninth imaging with 3.0T T2* GRE. Moreover, in a patient implanted with a pacemaker, which is only applicable for 1.5T MRI at present, the CMB seemed to disappear and appeared once again with a 1.5T T2*-weighted GRE at a slice thickness of 2.5 mm instead of 5 mm. CONCLUSIONS From this prospective study, we obtained 2 absolutely new findings that CMBs remained for as long as 9 years and a high-field or thin-slice MRI can detect concealed CMBs.

Adult T-Cell Leukemia With Invasion by Malignant Cells of the Parotid Glands Diagnosed by Ga-67 Imaging

Adult T-cell leukemia (ATL) shows several initial signs such as lymphadenopathy. Although oral cavity dryness is uncommon as an initial symptom of ATL, we encountered a case of a man who complained of just such an initial symptom and routine examination and the clinical course indicated that he was suffering from ATL. Further examination with Ga-67 citrate scintigraphy and a post-mortem study showed that lymphadenopathy had been induced by invasion by ATL cells of both parotid glands. Therefore, ATL should be considered in patients with an initial symptom of oral cavity dryness and enlargement of the parotid glands.

PS 13-15 CARVEDILOL ATTENUATES MECHANICAL STRETCHED MYOCARDIAL MITOCHONDRIA DYSFUNCTION BY PREVENTING TELOMERE-P53 PATHWAY

Objective: Cardiac hypertrophy increases with aging. It is known to cause the heart failure after the long-term pressure load. It has been reported that short telomere length and mitochondrial dysfunction were increasing with aging or aging-related diseases. Carvedilol is known as a convalescence improvement medicine for heart failure, but the mechanism has not been investigated in detail. P53 plays a role in regulating mitochondrial function through peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1a) repression. In this study, we investigated the effects of beta blocker carvedilol on telomere dependent apoptotic signal in mechanical stretched myocardium. Design and Method: We used H9C2 rat cardiomyocytes incubated with mechanical stretch chamber. Cells were subjected to 20 % cyclic uniaxial stretch for 72 h at a frequency of 1 Hz. We studied qPCR for the influence of various concentration of carvedilol (Carv). We estimated telomere length by Quantitative fluorescent in situ hybridization (Q-FISH) analysis. We also evaluated mitochondrial function using Mito tracker and cytochrome C activity. TUNEL assay was performed for evaluation of apoptosis. Results: Stretched cells showed reduced expression of tert, bcl-2, cleaved caspase-3, pgc-1a and increased expression of p53. Q-FISH analysis showed short telomere length. Whereas H9C2 cells treated with 0.1, 1, 10uM of Carv showed increased telomerase activity and reduced expression of p53 and telomere re-lengthening in a concentration dependent manner. Mitochondrial function which was measured by Mito tracker and cytochrome C activity assay also improved in Carv. Carv markedly reduced expression of TUNEL positive cell in the stretched cells. Conclusions: These results demonstrated that carvedilol was able to protect against myocardial mitochondria dysfunction and apoptosis by mechanical stretch stimulation. It suggested that carvedilol has a potential for the treatment of aging-related disease through the telomere-p53-PGC pathway.