Kanako Noritake

Molecular and tissue responses in the healing of rat calvarial defects after local application of simvastatin combined with alpha tricalcium phosphate

We have previously reported that healing of rat calvarial defects was enhanced by application of alpha tricalcium phosphate (alphaTCP) combined with simvastatin, a cholesterol synthesis inhibitor. The purpose of the present study was to investigate the cellular and molecular mechanisms in this phenomenon. Rat calvarial defects were grafted with alphaTCP with or without simvastatin or left untreated. Animals were sacrificed on 3, 7, 10, 14, and 21 days postoperatively and histological changes in the defect region were assessed. Gene expression patterns were examined by RT-PCR. Proliferation and migration of osteoprogenitor cells from the dura mater were increased in simvastatin group from day 3 to day 10 (p < 0.01). New bone formation was significantly increased in simvastatin group on day 14 and day 21 (p < 0.01). BMP-2 expression was significantly higher in simvastatin group on day 3 and day 14 (p < 0.05) and maintained until day 21. Increased upregulation of TGF-beta1 was also observed in the simvastatin group on day 7 (p < 0.05) which was maintained until day 14. These findings suggest that the proliferation and recruitment of osteoprogenitor cells were critical steps in early stage of bone healing and that these steps were enhanced by TGF-beta1 and BMP-2, which were stimulated by simvastatin.

Accelerated and Enhanced Bone Formation on Novel Simvastatin-Loaded Porous Titanium Oxide Surfaces

BACKGROUND With increasing application of dental implants in poor-quality bones, the need for implant surfaces ensuring accelerated osseointegration and enhanced peri-implant bone regeneration is increased. PURPOSE A study was performed to evaluate the osseointegration and bone formation on novel simvastatin-loaded porous titanium oxide surface. MATERIALS AND METHODS Titanium screws were treated by micro-arc oxidation to form porous oxide surface and 25 or 50 μg of simvastatin was loaded. The nontreated control, micro-arc oxidized, and simvastatin-loaded titanium screws were surgically implanted into the proximal tibia of 16-week-old male Wistar rats (n = 36). Peri-implant bone volume, bone-implant contact, and mineral apposition rates were measured at 2 and 4 weeks. Data were analyzed by one-way analysis of variance followed by Tukeys post hoc test. RESULTS New bone was formed directly on the implant surface in the bone marrow cavity in simvastatin-loaded groups since 2 weeks. Bone-implant contact values were significantly higher in simvastatin-loaded groups than control and micro-arc oxidized groups at both time points (p < .05). Peri-implant bone volume and mineral apposition rate of simvastatin-loaded groups were significantly higher than control and micro-arc oxidized groups at 2 weeks (p < .05). CONCLUSIONS These data suggested that simvastatin-loaded porous titanium oxide surface provides faster osseointegration and peri-implant bone formation and it would be potentially applicable in poor-quality bones.

Distinct effects of methamphetamine on autophagy–lysosome and ubiquitin–proteasome systems in HL-1 cultured mouse atrial cardiomyocytes

The aim of this study is to investigate the molecular mechanism underling the cardiotoxicity of methamphetamine, a psychostimulant drug that is currently abused in the world. A mouse atrial cardiac cell line, HL-1, which retains phenotypes of cardiac cells and serves as a useful model for examining cardiac pathophysiology, was used for this purpose. During treatment with 1mM methamphetamine (MAP) for 3-48h, massive but transient cytoplasmic vacuolization (3-12h) followed by an intracellular accumulation of granules (24-48h) was observed under light microscopy. The vacuoles were surrounded by the lysosome membrane marker LAMP1, while the granules colocalized with the autophagy markers LC3 and p62 as well as ubiquitinated proteins. Western blot analysis showed that LC3 was activated during MAP administration, although p62 was not degraded but rather accumulated. Concordant with p62 accumulation, the nuclear translocation of an anti-oxidative transcription factor, Nrf2, and the subsequent induction of its target gene, HO-1, was observed, suggesting an impairment of autophagic protein degradation and the subsequent activation of the p62/Nrf2/HO-1 pathway. In addition, proteomic analysis revealed a reduction in myosin heavy chain (MHC) protein levels during MAP administration. The ubiquitination of MHC and the induction of the muscle sarcomere protein-specific E3 ubiquitin ligases MuRF1 and atrogin-1 were proved by immunoprecipitation and quantitative real-time PCR, respectively. Taken together, the vacuolization of lysosomes and the subsequent accumulation of autophagosomes indicate an impairment of autophagic protein degradation during MAP administration; on the other hand, the ubiquitination and subsequent degradation of MHC indicate the proper progression of proteasomal degradation.

Peri-implantitis progression around thin sputtered hydroxyapatite-coated implants: clinical and radiographic evaluation in dogs.

PURPOSE Soft and hard tissue responses to experimental peri-implantitis around thin sputter hydroxyapatite (HA)-coated implants were evaluated and compared to the responses to implants with other surface treatments. MATERIALS AND METHODS Forty-eight dental implants with four different surfaces--machined (M), sandblasted/acid-etched (SA), 1-μm thin sputter HA-coated (S), and plasma-sprayed HA-coated (P)--were inserted into the mandibles of six beagle dogs. Three months later, experimental peri-implantitis was induced with ligatures to allow plaque accumulation. After a 4-month period of active breakdown, the ligatures were removed, and plaque accumulation continued for 5 additional months (progression period). Radiographic marginal bone levels, probing depths, clinical attachment levels, and modified Gingival Index were evaluated at baseline, after the active breakdown period, and after the progression period. RESULTS Significant increases in mean probing depths and clinical attachment levels were seen around all implants after active breakdown, but no significant differences were found during the progression period. Radiographic analysis revealed marginal bone loss of 1 to 1.7 mm during the active breakdown period. Additional bone loss occurred during the progression period (M 0.2 mm, SA 0.3 mm, S 0.2 mm, P 0.4 mm). CONCLUSION Comparable tissue behavior was demonstrated around dental implants with all four surfaces under peri-implantitis conditions. Thin sputter HA-coated implants possess the favorable osteoconductive properties of calcium phosphate coatings without exacerbating further peri-implant tissue breakdown during the progression of peri-implantitis.

Critical roles of Rho-associated kinase in membrane blebbing and mitochondrial pathway of apoptosis caused by 1-butanol

Alcohols are widely used as industrial solvents and chemical intermediates but can cause serious damage to human health. Nevertheless, few studies have addressed the molecular mechanisms underlying the cytotoxicity of industrial alcohols, with the notable exception of ethanol. The goal of our current study is to elucidate the molecular mechanism of cytotoxicity caused by primary alcohols containing longer carbon chains than ethanol. We find that 1-butanol induces morphological changes in H9c2 cardiomyoblastoma including nuclear condensation and membrane blebbing, both of which are features of apoptotic response. Moreover, a decrease in the mitochondrial membrane potential, the cytosolic release of cytochrome c, and the activation of caspase 9 and 3 was observed, thus revealing the activation of the mitochondrial apoptotic pathway by 1-butanol. The addition of Y-27632, a specific inhibitor of Rho-associated kinase (ROCK), suppressed the membrane blebbing and mitochondrial apoptotic pathway. In comparison z-VAD-fmk, a pan-caspase inhibitor, did not inhibit membrane blebbing but did prevent cell death following exposure to 1-butanol. These results indicate that mitochondrial pathway of apoptosis and membrane blebbing are parallel phenomena that occur downstream of ROCK. This kinase thus plays an essential role in 1-butanol cytotoxicity and subsequent cell death in H9c2 cells.

Direct Exposure to Ethanol Disrupts Junctional Cell-Cell Contact and Hippo-YAP Signaling in HL-1 Murine Atrial Cardiomyocytes.

Direct exposure of cardiomyocytes to ethanol causes cardiac damage such as cardiac arrythmias and apoptotic cell death. Cardiomyocytes are connected to each other through intercalated disks (ID), which are composed of a gap junction (GJ), adherens junction, and desmosome. Changes in the content as well as the subcellular localization of connexin43 (Cx43), the main component of the cardiac GJ, are reportedly involved in cardiac arrythmias and subsequent damage. Recently, the hippo-YAP signaling pathway, which links cellular physical status to cell proliferation, differentiation, and apoptosis, has been implicated in cardiac homeostasis under physiological as well as pathological conditions. This study was conducted to explore the possible involvement of junctional intercellular communication, mechanotransduction through cytoskeletal organization, and the hippo-YAP pathway in cardiac damage caused by direct exposure to ethanol. HL-1 murine atrial cardiac cells were used since these cells retain cardiac phenotypes through ID formation and subsequent synchronous contraction. Cells were exposed to 0.5–2% ethanol; significant apoptotic cell death was observed after exposure to 2% ethanol for 48 hours. A decrease in Cx43 levels was already observed after 3 hours exposure to 2% ethanol, suggesting a rapid degradation of this protein. Upon exposure to ethanol, Cx43 translocated into lysosomes. Cellular cytoskeletal organization was also dysregulated by ethanol, as demonstrated by the disruption of myofibrils and intermediate filaments. Coinciding with the loss of cell-cell adherence, decreased phosphorylation of YAP, a hippo pathway effector, was also observed in ethanol-treated cells. Taken together, the results provide evidence that cells exposed directly to ethanol show 1) impaired cell-cell adherence/communication, 2) decreased cellular mechanotransduction by the cytoskeleton, and 3) a suppressed hippo-YAP pathway. Suppression of hippo-YAP pathway signaling should be effective in maintaining cellular homeostasis in cardiomyocytes exposed to ethanol.

An autopsy case of vagus nerve stimulation following acupuncture

Acupuncture is one of the most popular oriental medical techniques in China, Korea and Japan. This technique is also popular as alternative therapy in the Western World. Serious adverse events are rare following acupuncture, and fatal cases have been rarely reported. A male in his late forties died right after acupuncture treatment. A medico-legal autopsy disclosed severe haemorrhaging around the right vagus nerve in the neck. Other organs and laboratory data showed no significant findings. Thus, it was determined that the man could have died from severe vagal bradycardia and/or arrhythmia resulting from vagus nerve stimulation following acupuncture. To the best of our knowledge, this is the first report of a death due to vagus nerve injury after acupuncture.

Hydrogen sulfide donor NaHS induces death of alveolar epithelial L2 cells that is associated with cellular shrinkage, transgelin expression and myosin phosphorylation

Hydrogen sulfide (H2S) is a highly toxic gaseous molecule that causes death to humans exposed to high concentrations. H2S is absorbed into the body through the alveolar epithelium and other tissues. The aim of this study is to evaluate the molecular mechanism underling acute lung injury caused by the inhalation of high concentrations of H2S. Rat lung epithelium-derived L2 cells were exposed to a H2S donor, NaHS, at concentrations of 2-4 mM for 1-6 hr. NaHS caused shrinkage and death of the cells without caspase activation. An actin-binding protein, transgelin, was identified as one of the NaHS-inducible proteins in the cells. NaHS increased myosin light chain (MLC) phosphorylation, indicating that actomyosin-mediated cellular contractility and/or motility could be increased after NaHS exposure. The administration of ML-7, a myosin light chain kinase (MLCK) inhibitor, accelerated cell death after NaHS exposure. Based on these data, we conclude that the increase in MLC phosphorylation in response to NaHS exposure is a cellular protective reaction against NaHS toxicity. Enhancements in smooth muscle cell properties such as transgelin expression and actomyosin-mediated contractility/motility might be involved in cell survival after NaHS exposure.

Autopsy findings of a patient with rapidly progressive massive ascites caused by alcoholic cirrhosis.

A 54-year-old man, who lived alone, was hospitalized due to rapid deterioration of the general condition over a three-week period caused by alcoholic cirrhosis. One month after he left hospital, he was found dead in his house by his friend. Three days before he was found dead, he had met his friend and seemed to be in poor condition. Autopsy was conducted by a medical examiner to clarify the cause of death. Externally, signs of severe jaundice were apparent over the whole body, along with extensive abdominal swelling and edema of the extremities. Autopsy findings demonstrated that the abdominal cavity contained an amount of massive turbid and slight pale reddish brown ascites (23 l). There were no findings of severe peritoneal inflammation. The liver (650 g) was elastic hard and had a micro-nodular surface, which showed severe atrophy. Microscopic examination of the liver showed clear pseudolobule with severe fibrosis in the stroma. There were no significant changes in the heart or brain. The stomach was empty and only a slight amount of intestinal contents. There was no ethanol detected in the blood or urine. The direct cause of his death was circulatory dysfunction due to massive accumulation of the ascites. The reasons for the massive ascites accumulation over 20 l in this case were (1) that he had no serious complications other than ascites; and (2) he did not have any medical treatment just before his death.

Interaction of carbon monoxide-releasing ruthenium carbonyl CORM-3 with plasma fibronectin

Inhaled carbon monoxide (CO) gas is highly toxic, but the human body produces low levels of CO for vasoregulation and other purposes. Given the established protective roles of low concentrations of CO gas against a panel of pathological insults, CO-releasing molecules (CORMs) have been developed and examined in disease models both in vitro and in vivo. Among CORMs, CORM-3 [Ru(CO)3Cl(glycinate)], a ruthenium carbonyl compound, has been extensively studied since it is water-soluble and is suitable for in vivo application. As one of the most prominent features of CO gas is its anti-fibrotic effect, we examined the effects of CORM-3 on mouse embryonic fibroblasts (MEFs). The application of 1 mM CORM-3 to MEFs resulted in the decreased syntheses of collagens I and III within 24 h, confirming an anti-fibrotic effect. To our surprise, CORM-3 caused a rapid (within 1 h) dissociation of cell-associated plasma fibronectin (FN) from the cells, which is associated with formation of a reduction-resistant oligomer of plasma FN. This aberrant oligomerization of plasma FN was reproduced using purified FN in vitro. Furthermore, we showed that RuCl3, but not another water-soluble CORM, CORM-A1 [Na2H3BCO2], also oligomerized plasma FN in vitro. FN depletion from the serum substantially ameliorates cell death by prolonged (72 h) exposure to CORM-3, suggesting a detrimental role of FN oligomerization on cell death. Taken together, we reveal for the first time that FN is a CORM-3-interactive plasma protein, and that the CORM-3-FN interaction is involved in the death of fibroblasts.