A synthetic porphyrin as an effective dual antidote against carbon monoxide and cyanide poisoning.

Simultaneous poisoning by carbon monoxide (CO) and hydrogen cyanide is the major cause of mortality in fire gas accidents. Here, we report on the invention of an injectable antidote against CO and cyanide (CN-) mixed poisoning. The solution contains four compounds: iron(III)porphyrin (FeIIITPPS, F), two methyl-ß-cyclodextrin (CD) dimers linked by pyridine (Py3CD, P) and imidazole (Im3CD, I), and a reducing agent (Na2S2O4, S). When these compounds are dissolved in saline, the solution contains two synthetic heme models including a complex of F with P (hemoCD-P) and another one of F with I (hemoCD-I), both in their iron(II) state. hemoCD-P is stable in its iron(II) state and captures CO more strongly than native hemoproteins, while hemoCD-I is readily autoxidized to its iron(III) state to scavenge CN- once injected into blood circulation. The mixed solution (hemoCD-Twins) exhibited remarkable protective effects against acute CO and CN- mixed poisoning in mice (~85% survival vs. 0% controls). In a model using rats, exposure to CO and CN- resulted in a significant decrease in heart rate and blood pressure, which were restored by hemoCD-Twins in association with decreased CO and CN- levels in blood. Pharmacokinetic data revealed a fast urinary excretion of hemoCD-Twins with an elimination half-life of 47 min. Finally, to simulate a fire accident and translate our findings to a real-life scenario, we confirmed that combustion gas from acrylic cloth caused severe toxicity to mice and that injection of hemoCD-Twins significantly improved the survival rate, leading to a rapid recovery from the physical incapacitation.

Transplantation of Fibroblast Sheets with Blood Mononuclear Cell Culture Exerts Cardioprotective Effects by Enhancing Anti-Inflammation and Vasculogenic Potential in Rat Experimental Autoimmune Myocarditis Model.

Fulminant myocarditis causes impaired cardiac function, leading to poor prognosis and heart failure. Cell sheet engineering is an effective therapeutic option for improving cardiac function. Naïve blood mononuclear cells (MNCs) have been previously shown to enhance the quality and quantity of cellular fractions (QQMNCs) with anti-inflammatory and vasculogenic potential using the one culture system. Herein, we investigated whether autologous cell sheet transplant with QQMNCs improves cardiac function in a rat model with experimental autoimmune myocarditis (EAM). Fibroblast sheets (F-sheet), prepared from EAM rats, were co-cultured with or without QQMNCs (QQ+F sheet) on temperature-responsive dishes. QQ+F sheet induced higher expression of anti-inflammatory and vasculogenic genes (Vegf-b, Hgf, Il-10, and Mrc1/Cd206) than the F sheet. EAM rats were transplanted with either QQ+F sheet or F-sheet, and the left ventricular (LV) hemodynamic analysis was performed using cardiac catheterization. Among the three groups (QQ+F sheet, F-sheet, operation control), the QQ+F sheet transplant group showed alleviation of end-diastolic pressure-volume relationship on a volume load to the same level as that in the healthy group. Histological analysis revealed that QQ+F sheet transplantation promoted revascularization and mitigated fibrosis by limiting LV remodeling. Therefore, autologous QQMNC-modified F-sheets may be a beneficial therapeutic option for EAM.

External administration of moon jellyfish collagen solution accelerates physiological wound healing and improves delayed wound closure in diabetic model mice.

INTRODUCTION: Artificial dermis is an effective therapeutic method for full-thickness dermal defects. However, the currently available artificial dermis made of porcine or bovine type I collagen has several limitations such as incomplete epithelialization and delayed migration of fibrogenic and angiogenic cells into the graft. We previously developed a composite dermal graft containing a mixture of moon jellyfish collagen and porcine type I collagen, and reported its stimulatory effect on both the re-epithelialization of the epidermis and the migration of fibrogenic and angiogenic cells into the graft. In the present study, we examined whether the same effect was observed by administering jellyfish collagen solution externally onto an artificial dermal graft made of bovine type I collagen. METHODS: We used a 6 mm full-thickness wound defect model. Moon jellyfish collagen was prepared as a concentrated 0.5% solution and dripped externally onto a transplanted artificial dermal graft made of bovine type I collagen. Wound repair and long-term dermal tissue remodeling were compared between mice administered jellyfish collagen solution on the bovine collagen graft and those transplanted with a composite dermal graft containing the same amounts of jellyfish and bovine collagens. The stimulatory effect of jellyfish collagen solution was also evaluated using diabetic dB/dB mice. RESULTS: External administration of jellyfish collagen solution onto the bovine collagen graft significantly accelerated wound closure compared to control saline. It also decreased the number of inflammatory cells infiltrating the wound and suppressed absorption of the transplanted graft, as well as reduced subsequent scar formation. Furthermore, external administration of jellyfish collagen solution onto the bovine collagen graft improved the delayed wound healing in diabetic model mice, and this effect was superior to that of the currently used basic fibroblast growth factor. CONCLUSIONS: External administration of moon jellyfish collagen solution onto a bovine collagen graft significantly accelerated physiological wound healing and prevented excessive scar formation. It also improved wound closure in diabetic model mice, confirming its therapeutic application for intractable skin ulcers caused by impaired wound healing.

Sensitive quantification of carbon monoxide in vivo reveals a protective role of circulating hemoglobin in CO intoxication.

Carbon monoxide (CO) is a gaseous molecule known as the silent killer. It is widely believed that an increase in blood carboxyhemoglobin (CO-Hb) is the best biomarker to define CO intoxication, while the fact that CO accumulation in tissues is the most likely direct cause of mortality is less investigated. There is no reliable method other than gas chromatography to accurately determine CO content in tissues. Here we report the properties and usage of hemoCD1, a synthetic supramolecular compound composed of an iron(II)porphyrin and a cyclodextrin dimer, as an accessible reagent for a simple colorimetric assay to quantify CO in biological samples. The assay was validated in various organ tissues collected from rats under normal conditions and after exposure to CO. The kinetic profile of CO in blood and tissues after CO treatment suggested that CO accumulation in tissues is prevented by circulating Hb, revealing a protective role of Hb in CO intoxication. Furthermore, hemoCD1 was used in vivo as a CO removal agent, showing that it acts as an effective adjuvant to O2 ventilation to eliminate residual CO accumulated in organs, including the brain. These findings open new therapeutic perspectives to counteract the toxicity associated with CO poisoning.

A Novel Composite Biomaterial Made of Jellyfish and Porcine Collagens Accelerates Dermal Wound Healing by Enhancing Reepithelization and Granulation Tissue Formation in Mice.

Background and Objective: Impaired dermal wound healing represents a major medical issue in today's aging populations. Granulation tissue formation in the dermis and reepithelization of the epidermis are both important and necessary for proper wound healing. Although a number of artificial dermal grafts have been used to treat full-thickness dermal loss in humans, they do not induce reepithelization of the wound, requiring subsequent epithelial transplantation. In the present study, we sought a novel biomaterial that accelerates the wound healing process. Approach: We prepared a composite biomaterial made of jellyfish and porcine collagens and developed a hybrid-type dermal graft that composed of the upper layer film and the lower layer sponge made of this composite biomaterial. Its effect on dermal wound healing was examined using a full-thickness excisional wound model. Structural properties of the dermal graft and histological features of the regenerating skin tissue were characterized by electron microscopic observation and immunohistological examination, respectively. Results: The composite biomaterial film stimulated migration of keratinocytes, leading to prompt reepithelization. The regenerating epithelium consisted of two distinct cell populations: keratin 5-positive basal keratinocytes and more differentiated cells expressing tight junction proteins such as claudin-1 and occludin. At the same time, the sponge made of the composite biomaterial possessed a significantly enlarged intrinsic space and enhanced infiltration of inflammatory cells and fibroblasts, accelerating granulation tissue formation. Innovation: This newly developed composite biomaterial may serve as a dermal graft that accelerates wound healing in various pathological conditions. Conclusion: We have developed a novel dermal graft composed of jellyfish and porcine collagens that remarkably accelerates the wound healing process.

Artificial oxygen carrier improves fatigue resistance in slow muscle but not in fast muscle in a rat in situ model.

The effects of liposome-encapsulated hemoglobin with high O2 affinity (h-LEH), an artificial O2 carrier in skeletal muscle, were studied by in situ fatigue resistance test in fast-type plantaris (PLT) and slow-type soleus (SOL) muscles with or without ischemia in the rat. The distal tendons of PLT and SOL muscles were isolated in situ and individually attached to the force transducers to record the developed tension in response to stimuli (80 Hz tetanus train, 1.5 minutes) to the ipsilateral sciatic nerve. The fatigue resistance test (five sets separated by 2-minute rests) was evaluated in terms of tension attenuation (fatigue) from the initial to the last tension (A) during each set, attenuation of the initial (B) or last tension (C) in each set, as compared to the first set in the presence or absence of ischemia or h-LEH (10 mL/kg). While ischemia significantly enhanced fatigue only in PLT, h-LEH showed no effect regardless of the perfusion pattern (normal/ischemia) or muscle-type (PLT/SOL) during each set (A). In parameter (B), set-by-set fatigue development was observed in PLT, whereas h-LEH-SOL showed a trend of advanced fatigue resistance. Such trends became clear in the parameter C (last tension), because h-LEH-SOL exerted, rather than decreased, the tension enhancement regardless of the presence or absence of ischemia, whereas there were no h-LEH effects in PLT. In addition, faster recovery of the nicotinamide adenine dinucleotide content in the muscle after 10 minutes of all fatigue tests was observed in h-LEH-SOL, while saline-SOL still showed a significantly higher value than that of control. These results suggested that additional O2 supply by h-LEH may accelerate the tricarboxylic acid cycle/electron transport chain in slow-type aerobic SOL muscle containing abundant mitochondria and contribute to the faster removal of muscle fatigue substances such as lactate.

Regeneration-associated cells improve recovery from myocardial infarction through enhanced vasculogenesis, anti-inflammation, and cardiomyogenesis.

BACKGROUND: Considering the impaired function of regenerative cells in myocardial infarction (MI) patients with comorbidities and associated risk factors, cell therapy to enhance the regenerative microenvironment was designed using regeneration-associated cells (RACs), including endothelial progenitor cells (EPCs) and anti-inflammatory cells. METHODS: RACs were prepared by quality and quantity control culture of blood mononuclear cells (QQMNCs). Peripheral blood mononuclear cells (PBMNCs) were isolated from Lewis rats and conditioned for 5 days using a medium containing stem cell factors, thrombopoietin, Flt-3 ligand, vascular endothelial growth factor, and interleukin-6 to generate QQMNCs. RESULTS: A 5.3-fold increase in the definitive colony-forming EPCs and vasculogenic EPCs was observed, in comparison to naïve PBMNCs. QQMNCs were enriched with EPCs (28.9-fold, P<0.0019) and M2 macrophages (160.3-fold, P<0.0002). Genes involved in angiogenesis (angpt1, angpt2, and vegfb), stem/progenitors (c-kit and sca-1), and anti-inflammation (arg-1, erg-2, tgfb, and foxp3) were upregulated in QQMNCs. For in vivo experiments, cells were administered into syngeneic rat models of MI. QQMNC-transplanted group (QQ-Tx) preserved cardiac function and fraction shortening 28 days post-MI in comparison with PBMNCs-transplanted (PB-Tx) (P<0.0001) and Control (P<0.0008) groups. QQ-Tx showed enhanced angiogenesis and reduced interstitial left ventricular fibrosis, along with a decrease in neutrophils and an increase in M2 macrophages in the acute phase of MI. Cell tracing studies revealed that intravenously administered QQMNCs preferentially homed to ischemic tissues via blood circulation. QQ-Tx showed markedly upregulated early cardiac transcriptional cofactors (Nkx2-5, 29.8-fold, and Gata-4, 5.2-fold) as well as c-kit (4.5-fold) while these markers were downregulated in PB-Tx. In QQ-Tx animals, de novo blood vessels formed a "Biological Bypass", observed macroscopically and microscopically, while PB-Tx and Control-Tx groups showed severe fibrotic adhesion to the surrounding tissues, but no epicardial blood vessels. CONCLUSION: QQMNCs conferred potent angiogenic and anti-inflammatory properties to the regenerative microenvironment, enhancing myocardiogenesis and functional recovery of rat MI hearts.

PEGylated carboxyhemoglobin bovine (SANGUINATE) ameliorates myocardial infarction in a rat model.

Artificial oxygen (O2 ) carriers were reported to be protective in ischemia/reperfusion (I/R) in various organs including the heart. In the current study, 20 rats underwent ligation (MI) of the left anterior descending artery, were treated with 10 mL/kg of PEGylated carboxyhemoglobin bovine (SANGUINATE, S+, n = 10) or saline (S-, n = 10) 10 minutes after MI and daily thereafter for 3 days, and were followed by weekly echocardiography for 4 weeks, when they had left ventricular pressure volume relationship (PVR) analyses followed by necropsy. Echocardiography showed an increase in end-systolic dimension rather than end-diastolic dimension, preserved fractional shortening (36 vs. 26%, P < .01), and milder mitral regurgitation in S+ compared with S- rats. PVR revealed a milder increase in end-systolic volume, larger stroke volume (101 vs. 74 µL, P < .005) and cardiac output (33.4 vs. 23.8 mL/min, P = .004) in S+ rats in actual determination and under a wide range of standardized loading conditions 4 weeks after MI. Excised heart showed significantly limited area of MI (8.9 vs. 13.3%, P = .028). The results suggest that SANGUINATE in short-term repeated doses may accelerate weight recovery, preserving the myocardium, mitral competence, and cardiac function after MI. The mechanism of action and optimal treatment for MI remain to be studied.

Propofol induces nuclear localization of Nrf2 under conditions of oxidative stress in cardiac H9c2 cells.

Oxidative stress contributes to myocardial ischemia-reperfusion injury, which causes cardiomyocyte death and precipitate life-threatening heart failure. Propofol has been proposed to protect cells or tissues against oxidative stress. However, the mechanisms underlying its beneficial effects are not fully elucidated. In the present study, we employed an in vitro oxidative injury model, in which rat cardiac H9c2 cells were treated with H2O2, and investigated roles of propofol against oxidative stress. Propofol treatment reduced H2O2-induced apoptotic cell death. While H2O2 induced expression of the antioxidant enzyme HO-1, propofol further increased HO-1 mRNA and protein levels. Propofol also promoted nuclear localization of Nrf2 in the presence of H2O2. Knockdown of Nrf2 using siRNA suppressed propofol-inducible Nrf2 and expression of Nrf2-downstream antioxidant enzyme. Knockdown of Nrf2 suppressed the propofol-induced cytoprotection. In addition, Nrf2 overexpression induced nuclear localization of Nrf2 and HO-1 expression. These results suggest that propofol exerts antioxidative effects by inducing nuclear localization of Nrf2 and expression of its downstream enzyme in cardiac cells. Finally, we examined the effect of propofol on cardiomyocytes using myocardial ischemia-reperfusion injury models. The expression level of Nrf2 protein was increased at 15 min after reperfusion in the ischemia-reperfusion and propofol group compared with ischemia-reperfusion group in penumbra region. These results suggest that propofol protects cells or tissues from oxidative stress via Nrf2/HO-1 cascade.

Effect of Oxygen Affinity of Liposome-Encapsulated Hemoglobin on Cerebral Ischemia and Reperfusion as Detected by Positron Emission Tomography in Nonhuman Primates.

We tested a hypothesis that liposome-encapsulated hemoglobin (LEH) with high oxygen (O2 ) affinity (h-LEH, P50 O2 = 10 mm Hg) may work better than LEH with low O2 affinity (l-LEH, P50 O2 = 40 mm Hg) in cerebral ischemia and reperfusion injury using positron emission tomography (PET) in primates undergoing middle cerebral artery (MCA) occlusion and reperfusion. Cerebral blood flow (CBF), O2 extract fraction (OEF), and cerebral metabolic rate of O2 (CMRO2 ) were successively determined by PET before ischemia, at 2 h of ischemia, immediately after reperfusion, and 3 h after reperfusion. Five minutes after MCA occlusion, 10 mL/kg of h-LEH (n = 6) was intravenously infused and compared with the results from previous data of monkeys treated with l-LEH (n = 6), empty liposome (n = 4), or saline (n = 8) as control. After the series of PET studies, the integrated area of cerebral infarction was determined histologically in 12 coronal brain slices. There was no significant difference in CBF, OEF, or CMRO2 up to 2 h of ischemia. A high CBF with a low OEF tended to be suppressed after reperfusion in LEH-treated monkeys. Three hours after reperfusion, the area of mild CMRO2 reduction (down to -30%) decreased (P < 0.05) and the area of mild CMRO2 increase (up to 30%) expanded in LEH-treated monkeys (P < 0.05) regardless of O2 affinity with no difference in the area of moderate-to-severe reduction (<-30%) or increase (<+30%) in CMRO2 compared to animals treated with empty liposome or saline. Distribution of CMRO2 reduction and histological damages showed that LEH mainly protected the cerebral cortex rather than basal ganglia where neuronal dendritic processes were severely lost. There was little difference between the animals treated with l-LEH or h-LEH both at 10 mL/kg or between treatment with empty liposome or saline. In conclusion, LEH was effective regardless of O2 affinity in preserving CMRO2 and in reducing the area of histological damage in the cerebral cortex, but not in basal ganglia, shortly after occlusion/reperfusion of MCA in monkey.

Liposome-Encapsulated Hemoglobin Accelerates Skin Wound Healing in Diabetic dB/dB Mice.

Since liposome-encapsulated hemoglobin with high O2 affinity (h-LEH, P50 O2  = 10 mm Hg) has been reported to accelerate skin wound healing in normal mice, it was tested in dB/dB mice with retarded wound healing, as seen in human diabetics. Two full-thickness dorsal wounds 6 mm in diameter encompassed by silicone stents were created in dB/dB mice. Two days later (day 2), the animals were randomly assigned to receive intravenous h-LEH (2 mL/kg, n = 7) or saline (2 mL/kg, n = 7). The same treatment was repeated 4 days after wounding (day 4), and the size of the skin lesions was analyzed by photography, surface perfusion was detected by Laser-Doppler imager, and plasma cytokines and chemokines were determined on days 0, 2, 4, and 7, when all animals were euthanized for morphological studies. The size of the ulcer compared to the skin defect or silicone stent became significantly reduced on days 4 and 7 in mice treated with h-LEH (47 ± 8% of original size), similar to the level in wild-type mice, compared to saline-treated dB/dB mice (68 ± 18%, P < 0.01). Mice treated with h-LEH had significantly attenuated inflammatory cytokines, increased surface perfusion, and increased Ki67 expression on day 7 in accordance with the ulcer size reduction, while there was no significant difference in chemokines, histological granulation, epithelial thickness, and granulocyte infiltration detected by immunohistochemical staining in the ulcer between the treatment groups. The results suggest that h-LEH (2 mL/kg) early after wounding may accelerate skin wound healing in dB/dB mice to levels equivalent to wild-type mice probably via mechanism(s) involving reduced hypoxia, increased surface perfusion, suppressed inflammation, accelerated in situ cell proliferation and protein synthesis.

Monitoring Mitochondrial Complex-I Activity Using Novel PET Probe 18F-BCPP-EF Allows Early Detection of Radiotherapy Effect in Murine Squamous Cell Carcinoma.

OBJECTIVES: Aerobic glycolysis, the main pathway of energy production in tumors (Warburg effect) allows detection of tumors by positron emission tomography (PET) using 18F-fluoro-2-deoxy-D-glucose (18F-FDG). Since ionizing radiation (IR) is reported to switch aerobic glycolysis to mitochondrial oxidative phosphorylation, radiotherapeutic efficacy was monitored by the activity of mitochondrial complex I (MC-I), using a new PET probe 18F-BCPP-EF, 18F-2-tert-butyl-4-chloro-5-{6-[2-(2-fluoro-ethoxy)-ethoxy] -pyridine-3-ylmethoxy}-2H-pyridazin-3-one, compared with 18F-FDG uptake and the apoptosis index. METHODS: Tumor uptake of 18F-BCPP-EF or 18F-FDG was examined in C3H/HeN mice inoculated with murine squamous cell carcinoma SCCVII at various time points after a single dose of x-ray irradiation at 0, 6, 15, or 30 Gy. Apoptosis incidence was determined by TUNEL staining in excised tumor tissue. RESULTS: Tumor growth suppression was dose-dependent; tumor grew 10-fold (0 Gy), 5-fold (6 Gy), 2-fold (15 Gy), and reduced to half in its volume (30 Gy) 14 days after treatment. 18F-BCPP-EF uptake was significantly increased as early as 3 days after 15 Gy or 30 Gy, when tumor size and apoptosis index showed no difference among radiation doses. In contrast, 18F-FDG uptake was initially increased dose-dependently, remained elevated up to 7 days, and eventually decreased 10 days after 30 Gy and also 14 days after 15 Gy when tumor size was already reduced. Apoptosis index was increased after irradiation but failed to correlate with tumor response. CONCLUSION: Tumor uptake of 18F-BCPP-EF was increased dose-dependently early after effective doses of IR when 18F-FDG uptake as well as apoptosis incidence were not indicative of tumor response. The results suggest that 18F-BCPP-EF is a promising "positive" MC-I imaging PET probe for early detection of efficacy of tumor radiotherapy.

Preoperative Risk Levels and Vascular Access in Transcatheter Aortic Valve Implantation-A Single-Institute Analysis.

Although transcatheter aortic valve implantation (TAVI) has been indicated for patients with high surgical risk, indications for or against the procedure become more difficult as vascular access becomes more proximal and/or invasive in order to accommodate patients with even higher risks. We compared preoperative factors including the European System for Cardiac Operative Risk Evaluation (EuroSCORE) and Society of Thoracic Surgeons Predicted Risk of Mortality (STS) score with postoperative survival in 195 patients undergoing TAVI during 2.5 years (January 2010 to June 2012), when vascular access routes were developed from iliofemoral (IL/Fm access, n = 149), axillo-clavicular, apical, and direct aortic approaches (alternative access, n = 46). Logistic regression analyses showed that alternative access was associated with reduced 30-day survival (P = 0.024), while high surgical risk (>15% in both EuroSCORE and STS score) was associated with reduced 1-year survival (P = 0.046). Thus, patients treated via IL/Fm access had acceptable outcome regardless of preoperative risk levels while patients with low surgical risk (<15%) had favorable outcome irrespective of access route. Since the remaining patients with combined risk factors, high preoperative risk level (>15%) requiring alternative access, had a prohibitive risk in our experience, they might have been considered untreatable or not amenable even to TAVI and offered medical or alternative managements.

Liposome-Encapsulated Hemoglobin Improves Tumor Oxygenation as Detected by Near-Infrared Spectroscopy in Colon Carcinoma in Mice.

Liposome-encapsulated hemoglobin (LEH) with high (h-LEH, P50 O2  = 10 mm Hg) or low O2 affinity (l-LEH, P50 O2  = 40 mm Hg) may improve O2 delivery to sensitize tumor tissues for radiotherapy. A total of 10 mL/kg of h-LEH, l-LEH, red blood cells (RBCs), or saline was infused in mice transplanted with murine colon carcinoma with near-infrared spectroscopy (NIRS) detectors set at the tumor (right leg) and intact muscle (left leg). NIRS recorded changes in the amount of oxyhemoglobin (oxyHb), deoxyhemoglobin (deoxyHb), and their sum (tHb) with the animals spontaneously breathing room air (10 min), pure O2 (5 min), and then back to room air. The tumor was finally excised for histological examination. In mice treated with h-LEH, tHb significantly increased compared to mice receiving other solutions. The magnitude was significantly attenuated in the tumor compared to the intact muscle under room air. Reciprocal changes in oxyHb and deoxyHb between intact muscle and tumor in response to infused solutions allowed assumption of average tissue PO2 between 30 and 40 mm Hg in muscle and at around 10 mm Hg in tumor. While O2 respiration increased oxyHb and decreased deoxyHb both in muscle and tumor, their sum or tHb consistently decreased in muscle and increased in tumor regardless of preceding infusion. Such responses were totally reversed when mice were placed under hypoxia (10% O2 ), suggesting that a lack of physiological circulatory regulation in tumor may account for heavier immunohistochemical staining for human hemoglobin in tumors of mice treated with h-LEH than with l-LEH. The results suggest that h-LEH may cause significant tumor oxygenation compared to RBC, l-LEH, or saline probably due to its nanometer size (vs. RBC) and high O2 affinity (vs. l-LEH) without increasing O2 content in the intact tissue (vs. O2 respiration) probably due to a lack of physiological circulatory regulation.

Utility of heme analogues to intentionally modify heme-globin interactions in myoglobin.

Myoglobin reconstitution with various synthetic heme analogues was reviewed to follow the consequences of modified heme-globin interactions. Utility of dimethyl sulfoxide as the solvent for water-insoluble hemes was emphasized. Proton NMR spectroscopy revealed that loose heme-globin contacts in the heme pocket eventually caused the dynamic heme rotation around the iron-histidine bond. The full rotational rate was estimated to be about 1400 s(-1) at room temperature for 1,4,5,8-tetramethylhemin. The X-ray analysis of the myoglobin containing iron porphine, the smallest heme without any side chains, showed that the original globin fold was well conserved despite the serious disruption of native heme-globin contacts. Comparison between the two myoglobins with static and rotatory prosthetic groups indicated that the oxygen and carbon monoxide binding profiles were almost unaffected by the heme motion. On the other hand, altered tetrapyrrole array of porphyrin dramatically changed the dissociation constant of oxygen from 0.0005 mm Hg of porphycene-myoglobin to ∞ in oxypyriporphyrin-myoglobin. Heme-globin interactions in myoglobin were also monitored with circular dichroism spectroscopy. The observation on several reconstituted protein revealed an unrecognized role of the propionate groups in protoheme. Shortening of heme 6,7-propionates to carboxylates resulted in almost complete disappearance of the positive circular dichroism band in the Soret region. The theoretical analysis suggested that the disappeared circular dichroism band reflected the cancellation effects between different conformers of the carboxyl groups directly attached to heme periphery. The above techniques were proposed to be applicable to other hemoproteins to create new biocatalysts. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson.

Ventricular conduction defects after transcatheter aortic valve implantation: a single-institute analysis.

Patients with aortic stenosis tend to develop ventricular conduction problems, which are known adverse events following transcatheter aortic valve implantation (TAVI). Changes in ventricular conduction status after TAVI were analyzed in 195 consecutive patients from a single institute registered in FRANCE2 between February 2010 and June 2012. Among the 195 patients, 29 had a prior pacemaker implantation (+PM) and 6 had acute catastrophic hemodynamics that made a full electrocardiogram (ECG) unavailable. Among the remaining 160, PM was newly required in 28 (17.5%, PM+) but not in 132 (PM-), which included 21 (13.1%) who developed new left bundle branch block (BBB), 12 (7.5%) had right BBB, and 99 (61.9%) had no change. While PM requirement had no correlation with preoperative factors, there was significant association with the development of right BBB with Edwards Sapien/XT (P = 0.003), and new left BBB (P = 0.012) and complete heart block requiring PM with CoreValve (22.6% vs. Edwards Sapien/XT, 7.4%, P = 0.016). Whereas postoperative survival regarding PM status (+PM, PM+, PM-), vascular access, valve size or type showed no difference, delayed heart block (n = 12, Day 2 or later) was associated with poor survival (P = 0.038) compared with the remaining PM+ patients with earlier onset (n = 16, Day 0 or 1). As a result, PM+ patients (n = 28) had significantly longer intensive care unit (ICU) stay and hospitalization than PM- or +PM patients. The results suggest that ventricular conduction problems requiring PM occurred more frequently after TAVI (17.5%) than with usual surgical replacement. Nonetheless, conduction problems failed to influence postoperative survival for up to 3 years on average with use of PM, but therefore did increase medical costs.

Real-time trafficking of PEGylated liposomes in the rodent focal brain ischemia analyzed by positron emission tomography.

Aliposomal drug delivery system was previously applied to ischemic brain model rats for the treatment of brain ischemia, and we observed that 100-nm-sized liposomes could extravasate and accumulate in the ischemic brain region even when cerebral blood flow was markedly reduced in permanent middle cerebral artery occlusion (p-MCAO) model rats. In the present study, we investigated the real-time cerebral distribution of polyethylene glycol (PEG)-modified liposomes (PEGliposomes) labeled with 1-[18F]fluoro-3,6-dioxatetracosane in p-MCAO rats by positron emission tomography (PET). [18F]-Labeled PEG-liposomes were intravenously injected into p-MCAO rats 1 h after the onset of occlusion, and then a PET scan was performed for 2 h. The PET scan showed that the signal intensity of [18F] gradually increased in the ischemic region despite the drastic reduction in cerebral perfusion, suggesting that PEG-liposomes had accumulated in and around the ischemic region. Therefore,drug delivery to the ischemic region by use of liposomes would be possible under ischemic conditions, and a liposomal drug delivery system could be a promising strategy for protecting the ischemic brain from damage before recovery from ischemia.

Effects of liposome-encapsulated hemoglobin on learning ability in tokai high-avoider rat after total brain ischemia and reperfusion.

Liposome-encapsulated hemoglobin with low O2 -affinity (l-LEH) was shown to be protective in focal brain ischemia and reperfusion (I/R) in rats and primates. We tested l-LEH in the transient whole brain ischemia in the Tokai high-avoider rat (THA), which has been selected, mated, and bred over 77 generations for a high and consistent learning ability determined by the Sidman avoidance test (SAT). Young/naïve (before SAT) and adult/parent (after SAT) THA rats underwent acute and complete four-vessel occlusion in the chest for 3 or 5 min, administration of 2 mL/kg of l-LEH, saline, or homologous washed red blood cells (RBCs), reperfusion, and resuscitation. One week later, all rats underwent SAT, open-field behavioral observation, Morris water maze tests, and morphological study. Whereas young/naïve rats treated with l-LEH retained a rapid and consistent learning curve as in nonischemic controls, THA rats treated with RBCs or saline had retarded learning response on SAT as well as reduced cellularity in the amygdala. Adult/parent rats with established memory on SAT maintained perfect achievement even after I/R. In contrast, l-LEH-treated rats showed no better performance on Morris water maze (function) or cellularity of the CA1 sector of the hippocampus (morphology) compared with the rats treated with RBCs. Although task performance on SAT and Morris water maze appeared antithetical, morphological observations corresponded to the respective functions, suggesting that l-LEH was protective only for the amygdala on SAT tasks but not for the CA1 sector of the hippocampus on spatial orientation as in our previous studies on focal brain I/R, where the cortex was preserved better than basal ganglia.