Hyperthermia maintains death receptor expression and promotes TRAIL-induced apoptosis

BACKGROUND

Tumor necrosis factor-related apoptosis-inducing ligand activates apoptotic pathways and could potentially be used in anticancer treatments. However, oral squamous cell carcinoma cells are known to be resistant to tumor necrosis factor-related apoptosis-inducing ligand-induced cell death. It has been previously reported that hyperthermia upregulates tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis in other cancers. As such, we evaluated whether hyperthermia upregulates tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in a tumor necrosis factor-related apoptosis-inducing ligand-resistant oral squamous cell carcinoma cell line.

METHODS

The oral squamous cell carcinoma cell line HSC3 was cultured and divided into hyperthermia and control groups. We investigated the antitumor effects of recombinant human tumor necrosis factor-related apoptosis-inducing ligand using cell proliferation and apoptosis assays. Additionally, we measured death receptor 4 and 5 levels, and determined death receptor ubiquitination status, as well as E3 ubiquitin ligase targeting of death receptor in both hyperthermia and control groups before recombinant human tumor necrosis factor-related apoptosis-inducing ligand administration.

RESULTS

Treatment with recombinant human tumor necrosis factor-related apoptosis-inducing ligand produced greater inhibitory effects in the hyperthermia group than in the control group. Moreover, death receptor protein expression in the hyperthermia group was upregulated on the cell surface (and overall), although death receptor mRNA was downregulated. The half-life of death receptor was several hours longer in the hyperthermia group; concomitantly, E3 ubiquitin ligase expression and death receptor ubiquitination were downregulated in this group.

CONCLUSION

Our findings suggested that hyperthermia enhances apoptotic signaling by tumor necrosis factor-related apoptosis-inducing ligand via the suppression of death receptor ubiquitination, which upregulates death receptor expression. These data suggest that the combination of hyperthermia and tumor necrosis factor-related apoptosis-inducing ligand has implications in developing a novel treatment strategy for oral squamous cell carcinoma.

Family with sequence similarity 20 member B regulates osteogenic differentiation of bone marrow mesenchymal stem cells on titanium surfaces

Successful bone regeneration on titanium (Ti) surfaces is a key process in dental implant treatment. Bone marrow mesenchymal stem cells (BMSCs) are fundamental cellular components of this process, and their early recruitment, proliferation, and differentiation into bone-forming osteoblasts are crucial. A proteoglycan (PG)-rich layer has been reported to exist between Ti surfaces and bones; however, the molecules that could potentially affect the formation of this layer remain unknown. Family with sequence similarity 20 member B (FAM20B) is a newly identified kinase that regulates the synthesis of glycosaminoglycans, an important component of the PG-rich layer. Because FAM20B is also closely associated with bone development, in this study, we examined the function of FAM20B in osteogenic differentiation of BMSCs on Ti surfaces. For this, BMSC cell lines with knocked down FAM20B (shBMSCs) were cultured on Ti surfaces. The results showed that the depletion of FAM20B reduced the formation of a PG-rich layer between the Ti surfaces and cells. The shBMSCs exhibited downregulated expression of osteogenic marker genes (ALP and OCN) and decreased mineral deposition. Moreover, shBMSCs reduced the molecular levels of p-ERK1/2, which plays an important role in MSC osteogenesis. The nuclear translocation of RUNX2, an important transcription factor for osteogenic differentiation, on the Ti surfaces is inhibited by the depletion of FAM20B in BMSCs. Moreover, the depletion of FAM20B reduced the transcriptional activity of RUNX2, which is important in regulating the expression of osteogenic genes. STATEMENT OF SIGNIFICANCE: Bone healing and regeneration on implanted titanium surfaces is a cell-material interaction. Such an interaction is enabled by bone marrow mesenchymal stem cells (BMSCs), and their early recruitment, proliferation, and differentiation into bone-forming osteoblasts are essential for bone healing and osseointegration. In this study, we found that the family with sequence similarity 20-B influenced the formation of a proteoglycan rich layer between BMSCs and the titanium surface and regulated the differentiation of BMSCs into bone-forming osteoblasts. We believe that our study contributes significantly to the further exploration of bone healing and osseointegration mechanisms on implanted titanium surfaces.

Prevalence and distribution of non-pulmonary vein atrial fibrillation triggers in real-world clinical settings

Background

Epidemiology of non-pulmonary vein (PV) triggers of atrial fibrillation (AF) is not fully known.

Purpose

This study aimed to clarify the prevalence and distribution of non-PV triggers in real-world clinical settings of AF catheter ablation.

Methods

One-thousand and twenty patients undergoing AF ablations were retrospectively analyzed (mean age 65 years old, 702 males (69%), 506 paroxysmal and 514 non-paroxysmal). Induction and observation of AF triggers were attempted using intravenous isoproterenol/adenosine triphosphate and repeated direct current cardioversion during AF in each session. Documentable non-PV AF triggers were characterized in the studied population. Premature atrial contractions that did not initiate AF were excluded.

Results

A hundred and twenty-six non-PV triggers were documented in 108 patients (10.6%). Non-PV trigger was documented in 6.3% of 1st session cases, whereas 30.9% of recurrent cases undergoing multiple sessions (p<0.0001). Left atrial (LA) posterior wall was the most prevalent site (N=34), followed by 30 intra-atrial septum (IAS), 29 superior vena cava (SVC), 13 crista terminalis, 7 right atrial (RA) free wall, 6 LA anterior wall, 3 coronary sinus (CS), 3 left atrial appendage, and 1 persistent left superior vena cava (LSVC). We classified those non-PV triggers into 4 groups; 43 LA, 33 thoracic veins (SVC, CS and LSVC), 30 IAS and 20 RA. Thoracic vein/RA origins were more prevalently detected in paroxysmal AF cases (57%) compared to non-paroxysmal AF (28%) (p<0.01). Conversely, LA origin was more prevalently detected in non-paroxysmal AF cases (48%) compared to paroxysmal AF (20%) (p<0.01).

Conclusions

Prevalence of non-PV trigger in cases undergoing multiple sessions is extremely high, suggesting a particular importance of non-PV trigger targeting in patients with recurrent AF undergoing 2nd or 3rd ablation sessions. Progressive nature of AF with newly generated AF triggers should be under consideration. Distributions of non-PV triggers are largely different between paroxysmal and non-paroxysmal AF. These findings may help ablation strategy regarding non-PV trigger targeting in practice.

Funding Acknowledgement

Type of funding sources: None.

Catheter ablation of persistent atrial fibrillation with heart failure improves hemodynamic status without deteriorating renal function in the elderly

Background/Introduction

Atrial fibrillation (AF) and heart failure (HF) frequently coexist in the elderly people, leading to worse clinical outcomes. HF with preserved ejection fraction (HFpEF) is the most common form of HF in the elderly, particularly in women, associated with AF. Ablation of AF in younger patients with HF with reduced EF (HFrEF) has become an established treatment option. However, clinical impact of ablation for persistent AF accompanying with HF in the elderly remains unclear.

Purpose

This study aimed to evaluate the effect of catheter ablation of persistent AF with heart failure in the elderly.

Methods

Consecutive 70 patients who underwent catheter ablation of persistent AF accompanying with HF (NYHA class> II, mean LVEF 51.7%) in our institution were retrospectively analyzed with regards to their 1-year clinical outcomes, HF markers such as BNP, renal function and transthoracic echocardiographic findings. Patients were dichotomized by age of 75-year-old (31 elderly vs 39 younger subjects) and separately analyzed.

Results

Mean age of the studied population was 70.5 year-old; 79.6±3.8 in the elderly group and 63.2±8.5 in the younger group. The elderly patients were more frequently females (45% vs 21%). Longstanding persistent AF was observed in 32% in the elderly and 28% in the younger group. Circumferential pulmonary vein isolation (PVI) was performed in all patients, with additional ablations of liner lesions and/or non-PV foci as needed. PVI alone was observed in 54.8% in the elderly and 41% in the younger group. There were no serious complications associated with the procedure. During 1 year after ablation, recurrence of AF was observed in 15 patients [6/31 (19%) in the elderly, 9/39 (23%) in the younger]. Readmission due to HF was observed in only 1 patient in the elderly and 2 patients in the younger group (3% vs. 5%, respectively). Cardiovascular events were observed in 3 patients [2/31 (6%) in the elderly, 1/39 (3%) in the younger], but there was no death. The BNP level as well as the NYHA class significantly decreased at 1-year follow-up compared to baseline in the both groups (Figure A and B). There was no change in serum creatinine level in the both groups (Figure C). The left atrial dimension and the LA volume index decreased at 1-year follow-up in the both groups (Figure D and E). The LVEF improved only in the younger group (Figure F).

Conclusions

Ablation of persistent AF in the elderly with HF (mostly with preserved EF) was associated with hemodynamic and functional improvements without deteriorating renal function in a mid-term, which was mostly comparable to the results in the younger.

Funding Acknowledgement

Type of funding sources: None.

Aggressive combined pharmacotherapy for heart failure reduces new onset atrial fibrillation

Backgrounds

Heart failure (HF) is a risk factor for new onset atrial fibrillation (AF), and the new onset AF is associated with a worse prognosis in HF patients. It has been reported that renin-angiotensin system inhibitor (RASi), β-blocker and mineral-corticoid receptor antagonist (MRA) prevent the new onset AF in HF patients. However, the effect of combined pharmacotherapy including angiotensin receptor neprilysin inhibitor (ARNI) and sodium glucose co-transporter 2 inhibitor (SGLT2i) on AF is unknown. We investigated the impact of contemporary regimen of combined pharmacotherapy for HF (RASi/ARNI+β-blocker+MRA+SGLT2i) on new onset AF.

Methods and results

We retrospectively studied rEF and mrEF patients without AF admitted to our hospital due to decompensated HF between 2015 and 2021 (n=366). Long-term (The mean follow-up was 635±421 days) incidence of new onset AF was investigated with regard to medical therapies. Patients were divided into 2 groups; patients with ≤2 HF drugs (n=181) and patients with ≥3 HF drugs (n=185). Patients with ≤2 HF drugs group were older (77.3 vs 67.0 years old, P<0.001), had a poorer renal function (Cre: 1.66 vs 1.09 mg/dl, P<0.001), and had a higher rate of ischemic heart disease (52 vs 38%, P=0.009), whereas left ventricular systolic function was better (EF: 31.9 vs 27.3%, P<0.001). There were 19 (10.5%) new onsets AF in the ≤2 HF drugs group, whereas only 7 (3.8%) had new onsets AF in the ≥3 HF drugs group (HR 0.36, 95% CI 0.15–0.85, P=0.01). All-cause death and hospitalization for HF were fewer in the ≥3 HF drugs group. A multivariate analysis revealed that ≥3 HF drugs use was an independent negative predictor of new onset AF (HR 0.37, 95% CI 0.15–0.93, P=0.03). Even after a propensity score matching of the clinical variables, the incidence of new onset AF was consistently fewer in the ≥3 HF drugs group (HR 0.36, 95% CI 0.13–0.99, P=0.04). Finally, patients with new onset AF had a higher rate of hospitalization for HF in the studied population (HR 9.68, 95% CI 5.67–16.5, P<0.01).

Conclusion

Aggressive combined pharmacotherapy for HF may be associated with fewer new onset AF in patients with HF.

Funding Acknowledgement

Type of funding sources: None.

Efficacy of semi-solidification of enteral nutrients for postoperative nutritional management with a nasogastric tube

Postoperative nutritional management with a nasogastric tube is often used to prevent malnutrition after oral and maxillofacial surgery. However, enteral nutrients (EN) may cause various complications due to their liquid formulation. In this study, we retrospectively evaluated the efficacy of semi-solid EN with a xanthan gum thickener through a nasogastric tube and examined patients' complications, nutritional status, and quality of life. We established two groups: an L group (n=20) to which we administered liquid EN, and an SS group (n=20) to which we administered semi-solidified EN. The primary outcome was the occurrence of gastrointestinal complications. The secondary outcome was a change in nutritional status based on body weight and controlling nutritional status. The other outcome was the improvement in the patients' quality of life, assessed by the administration time. During nutritional management with a nasogastric tube, the median daily administration time in the L group was 9.0 hours, and 9 patients experienced diarrhea. In the SS group, the median daily feeding time was 2.3 hours, and only 2 patients experienced diarrhea. Both groups exhibited a decrease in body weight while controlling nutritional status scores were maintained. Semi-solidification of EN may be useful for postoperative nutritional management after oral and maxillofacial surgery by reducing complications, maintaining nutritional status, and shortening administration time.

Cyclin dependent kinase 1 (CDK1) positively regulates cardiac hypertrophy and fibrosis via TGF-beta pathway

Background

Transforming growth factor beta (TGF-β) critically mediates cardiac fibrosis by transforming fibroblasts to myofibroblasts in pathological conditions. Cyclin dependent kinases (CDKs), cell cycle-regulating proteins, are known to be intimately involved in cardiac fibrosis. Among CDK isoforms, CDK1 is essential for cell cycle progression and cell division. It is reported some interphase CDKs such as CDK4 or CDK6 were involved in cardiac fibrosis, however, detailed mechanisms of cardiac fibrosis through CDK1 and its interactions with TGF-β in cardiac fibrotic process haven't been elucidated. We hypothesize that CDK1 is involved in cardiac fibrotic process via TGF-β pathway and its suppression decreases TGF-β expression and transformation to myofibroblasts from fibroblasts presenting antifibrotic effect.

Methods and results

Isolated neonatal rat cardiac fibroblasts were treated with angiotensin II (ANG II, 1 μM, 24 h) or phosphate-buffered saline (PBS). ANG II increased CDK1 and TGF-β in cardiac fibroblasts, by 97% and 292%, respectively (p<0.05). Administration of Ro-3306, a specific CDK1 inhibitor (1 μM, 24 h), suppressed TGF-β protein levels in ANG II-treated cardiac fibroblasts by 58% (p<0.05). Similarly, knockdown of CDK1 by RNA silencing also inhibited ANG II-induced increases in TGF-β in cardiac fibroblasts by 39% (p<0.05). ANG II increased alpha-smooth muscle actin (α-SMA), which is a marker of myofibroblasts, and knockdown of CDK1 significantly suppressed it by 49% (p<0.05). In vivo study, 11-week-old male C57BL/6J mice were administered ANG II continuously with infusion pump, at a dose of 1000 ng/kg/min, for a week. Also, Ro-3306 was intraperitoneally injected at a dose of 2 mg/kg/day, every other day, for a week. First, Ro-3306 attenuated ANG II-mediated cardiac hypertrophy indicated by heart weight and echocardiographic parameter as to left ventricular wall thickness. Second, CDK1 and TGF-β expression were significantly augmented in ANG II-infused mice by 404% and 113%, respectively (p<0.05). Injection of Ro-3306 suppressed TGF-β protein levels by 48%, although the difference wasn't statistically significant (p=0.09). Finally, histopathological examination (Masson's trichrome stain) demonstrated remarkable repression of ANG II-induced cardiac fibrosis by Ro-3306.

Conclusions

CDK1 positively controls cardiac fibrotic process by regulating transformation to cardiac myofibroblasts from fibroblasts via TGF-β pathway. It also presents an antihypertrophic effect on ANG II stimulation. CDK1 is a potential therapeutic target of cardiac fibrosis and hypertrophy.

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): KAKENHI

Clinical features and prognosis of acute myocardial infarction due to coronary artery embolism

Background

Coronary artery embolism (CE) is one of the important causes of acute coronary syndrome (ACS). The feature of CE is that angiographic evidence of coronary artery embolism and thrombosis without atherosclerotic components. However, the prevalence of CE remains unknown because of the diffifulty to diagnose in the acute settings. A recent retrospective analysis suggested that up to 3% of ACS cases may result from CE.

Purpose

The aim of this study was to elucidate the prevalence, clinical features and long-term outcomes including all-cause and cardiac death.

Methods

We analysed the consecutive 2695 patients with first AMI performed coronary intervention between January 2004 and July 2017. CE was diagnosed by clinical histories and angiographic findings. We retrospectively evaluated the clinical and lesion characteristics and outcomes including all-cause and cardiac death.

Results

The prevalence of CE was 2.0% (n=55; CE group and n=2640; non-CE group), including 8 (15%) patients with multivessel CE. The CE group had higher average age (70.8±14.9 vs. 68.4±12.6, p<0.01), prevalence of female (54% vs. 27%, p<0.01), lower prevalence of smoking (34% vs. 62%, p<0.01). The common causes with CE were atrial fibrillation (47%), and malignant tumor (9%), and cardiomyopathy (5%), and patent foramen ovale (4%). Only 20% of patients with CE were treated with anti-coagulant therapy. The rate of distal infarction site (defined as #4, #8, #14–15) was significantly higher in CE group than non-CE group (54.0% vs. 4.9%, p<0.01). During median follow-up of 53.6 [32.6–77.3] months, CE and thromboembolism recurred in 5 patients (CE: 1 patient, stroke 4 patients). The 4-year incidence of all-cause death was significantly higher in the CE group, but cardiac death was not significantly different between the groups (28.8% vs. 14.8%, p=0.03; 12.8% vs. 5.1%, p=0.11).

Conclusion

Compared with non-CE group, the prevalence of distal infarction site was significantly higher in the CE group, and the incidence of cardiac death is not significantly different.

Funding Acknowledgement

Type of funding source: None

Smooth muscle cell-specific SOCS3 deficiency promote pericardial fibrosis and diastolic dysfunction in aging mice

Background

Suppressor of cytokine signaling-3 (SOCS3) is a cytokine-inducible negative regulator of signal transducer and activator of transcription-3 (STAT3) signaling pathway. We have previously shown that cardiac-specific SOCS3 deficiency spontaneously develop cardiac dysfunction with advanced age. However, the role of SOCS3 in smooth muscle cells in cardiovascular pathophysiology remains elusive. In this study, we determined whether STAT3 and SOCS3 in smooth muscle cells would play a role in cardiovascular pathophysiology.

Methods and results

To target inactivation of the SOCS3 gene to smooth muscle cells, SOCS3-flox mice were bred with transgenic mice expressing Cre recombinase under control of the mouse SM22-α promoter (sm-SOCS3-KO mice). Left ventricular weight to body weight ratio was significantly increased in sm-SOCS3-KO mice compared with wild-type mice at 12 months of age (p<0.05). Echocardiographic analyses of smSOCS3-KO mice showed significantly increased left ventricular diastolic dysfunction compared with wild-type from 12 months of age (p<0.05). Sirius-red staining revealed that thickness of pericardium and cardiac interstitial fibrosis in sm-SOCS3-KO mice were markedly greater compared with wild-type mice at 12 months of age (p<0.05). Western blot analyses showed that phosphorylated STAT3 was significantly increased in sm-SOCS3-KO hearts compared with wild-type mice at 12 months of age (p<0.05), whereas no significant differences were observed at 2 months of age. To investigate the mechanism that gave rise to promoted cardiac fibrosis and diastolic dysfunction during aging in sm-SOCS3-KO, we conducted a real-time PCR array analysis for fibrosis. The expression of pro-fibrotic CTGF (connective tissue growth factor), PDGFb (platelet growth factor-b), and TGF (transforming growth factor) family genes including TGFb1, TGFb2, and TGFb3, were significantly higher in sm-SOCS3-KO hearts than those in wild-type at 6 months of age.

Conclusion

Thus, smooth muscle cell-specific SOCS3 deletion induces increased pericardial fibrosis, cardiac interstitial fibrosis, and increased diastolic dysfunction in aging mice, possibly through the augmentation of pro-fibrotic growth factors.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant JSPS KAKENHI

Chondroitin-4-sulfate transferase-1 depletion inhibits formation of a proteoglycan-rich layer and alters immunotolerance of bone marrow mesenchymal stem cells on titanium oxide surfaces

Successful osseointegration is essential for dental implants. However, the complete molecular mechanism of osseointegration remains to be elucidated. In this study, we focused on the proteoglycan (PG)-rich layer between titanium oxides (TiOx) and bone, and chondroitin-4-sulfate transferase-1 (C4ST-1), which forms the sugar chain in PGs. Human bone marrow mesenchymal stem cells (hBMSCs) depleted of C4ST-1 were cultured on titanium (Ti) plates, and the interface between hBMSCs and TiOx was analyzed using transmission electron microscopy. Immunotolerance, proliferation, initial adhesion, and calcification of the cells were analyzed in vitro. At 14 days of cultivation, a PG-rich layer was observed between hBMSCs and TiOx. However, the PG-rich layer was reduced in C4ST-1-depleted hBMSCs on TiOx. Real-time RT-PCR showed that conditioned media increased the levels of expression of M1-macrophage markers in human macrophages. However, depletion of C4ST-1 did not affect calcification, cell proliferation, or initial cell adhesion on Ti plates. These results suggested that C4ST-1 in hBMSCs affects their immunotolerance and alters the formation of PG-rich layer formation on TiOx.

The effect of macrophages on an atmospheric pressure plasma-treated titanium membrane with bone marrow stem cells in a model of guided bone regeneration

Guided bone regeneration (GBR) is an established treatment. However, the mechanisms of GBR are not fully understood. Recently, a GBR membrane was identified that acts as a passive barrier to regenerate bone via activation and migration of macrophages (Mps) and bone marrow stem cells (BMSCs). Atmospheric pressure plasma treatment of the titanium membrane (APP-Ti) activated macrophages. The purpose of this study was to analyze whether macrophages attached to an APP-Ti membrane affected differentiation of BMSCs in a GBR model. Human THP-1 macrophages (hMps) were cultured on non-treated Ti (N-Ti) and APP-Ti membrane. Macrophage polarization was analyzed by RT-PCR and immunocytochemistry. Secreted proteins from hMps on N-Ti and APP-Ti were detected by LC/MS/MS. hBMSCs were co-cultured with hMps on N-Ti or APP-Ti and analyzed by osteogenic differentiation, Alizarin red S staining, and alkaline phosphatase (ALP) activity. N-Ti and APP-Ti membrane were also implanted into bone defects of rat calvaria. hMps on APP-Ti were polarized M2-like macrophages. hMps on N-Ti secreted plasminogen activator inhibitor-1 and syndecan-2, but hMps on APP-Ti did not. hBMSCs co-cultured with hMps on APP-Ti increased cell migration and gene expression of osteogenic markers, but suppressed mineralization, while ALP activity was similar to that of hMps on N-Ti in vitro. The volume of newly formed bone was not significantly different between N-Ti and APP-Ti membrane in vivo. M2 polarized hMps on APP-Ti suppressed osteogenic induction of hBMSCs in vitro. The indirect role of hMps on APP-Ti in newly formed bone was limited.

P6283Downregulation of Tim44 exacerbates oxidative stress-induced ROS production and cardiomyocytes death by reducing mitochondrial SOD2

Background

Mitochondrial dysfunction has been highlighted as a critical driver of cardiac remodeling and failure. Mitochondria contains about 1500 proteins, 99% of which are encoded in the nuclear genome. Therefore, protein import into mitochondria is essential to maintain mitochondrial function. Previous reports suggest that nuclear-encoded mitochondrial precursor proteins import into mitochondria by multiple complex; translocase of outer membrane (TOM), translocase of inner membrane (TIM), and protein associated motor (PAM). However, the role of these protein import machineries of mitochondria in cardiac remodeling remains to be elucidated.

Objective

The purpose of this study was to elucidate the role of TOM, TIM, and PAM complex in cardiac remodeling and cardiomyocyte death.

Methods and results

C57BL/6J mice were subjected to myocardial infarction (MI) by permanent ligation of left anterior descending artery. Four weeks after operation, MI-mice demonstrated left ventricular (LV) dilation (LV end-diastolic dimension: 3.91 vs. 5.54 mm, n=8–11, p<0.05) and dysfunction (LV fractional shortening: 33.3 vs. 7.7%, n=8–11, p<0.05). Tim44 protein levels, a component of PAM complex, in mitochondrial fraction from non-infarcted left ventricle were significantly decreased compared with those in the heart from sham-operated mice by 39% (p<0.05), whereas other proteins related to TOM, TIM and PAM complex such as Tom20, Tom22, Tom40, Tom70, Tim22, Tim23 and mtHSP70 were not altered between MI-mice and sham-mice. In addition, blue-native polyacrylamide gel electrophoresis revealed that a protein complex associated to Tim44 was significantly decreased in non-infarcted LV by 40% (p<0.05). Superoxide dismutase 2 (SOD2), a mitochondrial matrix protein, was decreased in mitochondrial fraction from non-infarcted LV by 20% (p<0.05), accompanied by enhancing protein carbonylation, a marker of oxidative stress, by 40% (p<0.05). To assess the role of Tim44, it was downregulated by small interfering RNA in cultured neonatal rat ventricular myocytes (NRVMs). Knockdown of Tim44 significantly decreased SOD2 protein levels in mitochondrial fractionation (22%, p<0.05), with no significant changes in its mRNA levels. Furthermore, knockdown of Tim44 significantly increased protein carbonylation (20%, p<0.05) and cleaved caspase 3 (47%, p<0.05) and decreased cell viability (69%, p<0.05), assessed by cell titer assay, in H2O2-treatred NRVMs.

Conclusions

Downregulation of Tim44 exacerbates oxidative stress-induced ROS production and cardiomyocytes death, which is associated with a decrease in mitochondrial SOD2. Endogenous Tim44 might play a protective role in cardiac remodeling by attenuating oxidative stress and cardiomyocyte death via SOD2 import into mitochondria.

P1606Glutamine-fructose-6-phosphate amidotransferase 2 mediates isoproterenol-induced cardiac hypertrophy by increasing Akt O-GlcNAcylation through hexosamine biosynthesis pathway

Background

Cardiac hypertrophy is an independent risk factor for heart failure and cardiac death. Hexosamine biosynthesis pathway (HBP), an accessory pathways of glycolysis, is known to be involved in the attachment of O-linked N-acetylglucosamine motif (O-GlcNAcylation) to proteins, a post-translational modification. However, the role of HBP has not been determined in pathological cardiac hypertrophy.

Purpose

The purpose of this study to examine whether glutamine-fructose-6-phosphate amidotransferase 2 (GFAT2), a critical enzyme of HBP, mediates cardiac hypertrophy by protein O-GlcNAcylation and activating hypertrophic signaling in cardiomyocytes.

Methods and results

C57BL/6J mice were treated with isoproterenol (ISO: 15 mg/kg/day, 1 week) with or without 6-Diazo-5-oxo-L-norleucine (DON, an inhibitor of GFAT: 500 μg/kg/day, 1week). ISO-treated mice (ISO+vehicle) showed cardiac hypertrophy, which were attenuated in ISO and DON-treated mice (ISO+DON) (heart weight to tibial length ratio: 7.70±0.09 vs. 7.11±0.15 mg/mm, n=12, p<0.05, left ventricular wall thickness: 1.05±0.02 vs. 0.86±0.03 mm, n=6, p<0.05). Cardiomyocyte cross-sectional area was also decreased in ISO+DON compared with ISO+vehicle (309±25 vs. 252±13 mm2, n=,3 p<0.05). Whereas expression levels of GFAT2 and protein O-GlcNAcylation in the heart were increased in ISO+vehicle compared with control+vehicle by 3.3 and 1.5 folds, respectively (n=9 and n=9, p<0.05), expression levels of O-GlcNAc transferase (OGT) and the β-N-acetylglucosaminidase (OGA), other enzymes regulating O-GlcNAcylation, were not altered in both groups, indicating that ISO activated HBP by GFAT2. Protein O-GlcNAcylation in ISO+DON was lower than that in ISO+vehicle by 83% (n=9, p<0.05). In addition, phosphorylation of Akt, a critical mediator of cardiac hypertrophy, but not other mediators of cardiac hypertrophy such as ERK, JNK, or p38MAPK, was significantly decreased in ISO+DON by 76% (n=9, p<0.05). In cultured neonatal rat ventricular myocytes, treatment with ISO (1μM, 12h) increased the expression levels of GFAT2 and protein O-GlcNAcylation by 1.3 and 1.5 folds, respectively (n=6 and n=6, p<0.05), but not GFAT1. Furthermore, ISO stimulation increased a direct O-GlcNAcylation of Akt by 1.4 folds (n=3, p<0.05). Downregulation of GFAT2 by RNA silencing decreased cell size by 82% (n=6, p<0.05) and protein O-GlcNAcylation and phosphorylation of Akt by 76% and 54%, respectively (n=9 and n=9, p<0.05) in cardiomyocyte treated with ISO. Conversely, administration of glucosamine, a substrate of HBP, increased protein of O-GlcNAcylation and phosphorylation of Akt by 1.3 and 1.8 folds, respectively (n=6 and n=6, p<0.05).

Conclusions

GFAT2, a limiting enzyme of HBP, mediates pathological cardiac hypertrophy by Akt activation probably due to its O-GlcNAcylation. GFAT2-O-GlcNAcylation-Akt pathway might be a potential novel therapeutic target for cardiac hypertrophy.

P1627Increased pericardial fibrosis and cardiac dysfunction in smooth muscle cell-specific SOCS3 deficient mice

Background

Suppressor of cytokine signaling-3 (SOCS3) is an intrinsic negative-feedback regulator of signal transducer and activator of transcription-3 (STAT3) signaling pathway. We have previously shown that myocardial SOCS3 plays an important role in cardiac hypertrophy and survival; however, the role of SOCS3 in smooth muscle cells in cardiovascular pathophysiology remains elusive. In this study, we determined whether STAT3 and SOCS3 in smooth muscle cells would play a role in cardiovascular pathophysiology.

Methods and results

To target inactivation of the SOCS3 gene to smooth muscle cells, SOCS3-flox mice were bred with transgenic mice expressing Cre recombinase under control of the mouse SM22-α promoter (sm-SOCS3-KO mice). Left ventricular weight to body weight ratio was significantly increased in sm-SOCS3-KO mice compared with wild-type mice at 52 weeks of age (p<0.05). Echocardiographic analyses of sm-SOCS3-KOmice showed significantly decreased cardiac function compared with wild-typefrom 52 weeks of age (p<0.05). Interestingly, Sirius-red staining revealed that thickness of pericardium in sm-SOCS3-KOmice was markedly greater compared with wild-typemice at 52 weeks of age (p<0.05). Cardiac interstitial fibrosis in sm-SOCS3-KOmice was also greater compared with wild-typemice (p<0.05). Western blot analyses showed that phosphorylated STAT3 was significantly increased in sm-SOCS3-KOhearts compared with wild-typemice at 52 weeks of age (p<0.05), whereas no significant differences were observed at 7 weeks of age. Immunostaining revealed that phosphorylated STAT3 positive cells were in thickened pericardial area in sm-SOCS3-KOhearts. Some infiltrated inflammatory cells were also found in thickened pericardial area in sm-SOCS3-KOmice hearts.

Conclusion

These results suggest that STAT3 and its negative-feedback regulator SOCS3 in smooth muscle cells play an important role in the pathogenesis of pericardial fibrosis and cardiac dysfunction.

P2693Late catch-up phenomenon and late-term target lesion revascularization of two-stenting for coronary bifurcation lesions between first and second generation drug-eluting stents

Background

The second generation drug-eluting stent (G2-DES) has been reported as superior to the first generation drug-eluting stent (G1-DES) in mid-term outcomes. However, the late-term outcomes between G1-DES and G2-DES in two-stenting for coronary bifurcation lesions are not well studied.

Purpose

To evaluate the late catch-up phenomenon and late-term target lesion revascularization (TLR) of two-stenting for coronary bifurcation lesions between G1-DES and G2-DES.

Methods

This study included 1133 lesions in 1089 patients undergoing drug eluting stent implantation with two stenting from 2004 to 2016. These consisted of 496 G1-DES implanted lesions and 637 G2-DES implanted lesions. Late-term follow-up angiography was performed without in-stent restenosis (ISR) and TLR at mid-term follow-up in 582 lesions (242 G1-DES lesions and 340 G2-DES lesions). ISR was defined as more than 50% restenosis. Late catch-up phenomenon was defined as ISR without ISR within 1 year following index stent implantation. Late-term TLR was defined as from 1 to 5 year TLR. Bifurcation lesions were defined as the main branch ranging from the proximal stem to the distal main branch with boundaries defined by 5 mm proximal and distal to the stent-implanted area, and the side branch ranging from the bifurcation carina to the distal side branch with boundaries defined by the carina and 5 mm distal to the stent-implanted area.

Results

The median follow-up duration was 5.1 years (the first and third quarters, 3.2 and 7.1 years). The late-catch up phenomenon rate significantly differed between the G1-DES and G2-DES groups (16.9% vs 8.4%, p=0.001). A significant difference in late catch-up between the same two groups was also observed in bifurcation lesions of the main branch (5.0% vs 0.6%, p=0.001) and side branch (10.3% vs 5.6%, p=0.033), respectively. The 5-year cumulative rates also differed between the two groups in TLR (8.2% vs 3.7% log-rank p=0.001), and late-term TLR (7.0% vs 3.6% log-rank p=0.001).

Conclusion

Two-stenting using G2-DES, compared with G1-DES, significantly reduced late-term restenosis and TLR. The restenosis rate in bifurcation area may be associated with differences between two groups in late-term outcome.

P6305Activation of invariant natural killer T cells ameliorates doxorubicin-induced cardiomyopathy

Background

Invariant natural killer T (iNKT) cells orchestrate tissue inflammation via regulating various cytokine productions, especially strongly upregulating interferon (IFN)-γ. Activation of iNKT cells have been previously reported to exert protective effects against post-infarcted cardiac remodeling and cardiac ischemia/reperfusion injury. However, the role of iNKT cells has not been determined in doxorubicin (DOX)-induced cardiomyopathy.

Purpose

The purpose of this study was to examine whether the activation of iNKT cells by α-galactosylceramide (αGC), which specifically activates iNKT cells, could affect DOX-induced cardiomyopathy, and if so, to elucidate its downstream target.

Methods

C57BL/6J mice were received the intraperitoneal injection of either αGC (0.1μg/g, n=11) or vehicle (n=13). After 1 week, these mice were treated with a low dose of DOX (18mg/kg via intravenous 3 injections over 1 week), and were followed during 14 days.

Results

DOX mice (DOX+vehicle) showed left ventricular (LV) dysfunction and dilatation, which were significantly ameliorated in DOX mice receiving αGC (DOX+αGC) (LV fractional shortening: 27.4±4.31 vs. 31.5±4.62%, p<0.05, LV end-diastolic diameter: 3.70±0.16 vs. 3.32±0.23mm, p<0.05), with no significant changes in arterial pressure, body weight, and food consumption, 14 days after DOX injection. DOX+vehicle demonstrated a significant decrease in myocardial gene expression of Vα14Jα18, a specific marker of iNKT cells, and IFN-γ compared with control mice. Vα14Jα18 expression levels were higher in DOX+αGC than DOX+vehicle by 9.2 folds (p<0.05). Consistent with this change, IFN-γ was higher in DOX+αGC than DOX+vehicle by 4.4 folds (p<0.05), whereas interleukin (IL)-1, IL-4, IL-6, IL-10, IL-17, IL-23, and tumor necrosis factor (TNF)-α were not altered in both groups. Phosphorylation of Akt, its active form, in the heart was significantly increased in DOX+αGC compared with DOX+vehicle by 1.8 folds (p<0.05).

Conclusions

Activation of iNKT cells by αGC play a protective role against DOX-induced cardiac dysfunction, which was associated with enhancing expression of IFN-γ and activating Akt. Therapies designed to activate iNKT cells might be beneficial to protect the heart from DOX injury.

P5374Genetic deletion of IL-22 increased cardiac rupture after myocardial infarction in mice

Background

Interleukin-22 (IL-22) is a member of the IL-10 cytokine family, which mainly targets epithelial cells and does not target immune cells. Recently, it has been reported that IL-22 play roles in tissue repair in the skin and the liver; however, role of IL-22 in the process of tissue repair after myocardial infarction (MI) is unknown. Here, we investigated the role of IL-22 in tissue repair process after MI.

Methods and results

First, we examined the expression of IL-22 and its receptor IL-22RA1 in the wild type (WT) mice by real-time PCR. The expression of IL-22 and IL-22RA1 in the hearts were significantly increased 3 days after MI (p<0.05). To clarify the role of IL-22 in the heart after MI, we produced MI model in the WT mice and IL-22 knockout (KO) mice. We found that the IL-22 KO mice had significantly higher mortality than the WT mice after MI (p<0.05). Approximately 80% of the IL-22 KO mice died with cardiac rupture after MI. The infarct size which was estimated by evans blue dye and triphenyltetrazolium chloride staining at 3 days after MI was comparable between the IL-22 KO mice and the WT mice. Next, we performed real time PCR and PCR array analysis for tissue fibrosis and repair genes. We found that alpha-smooth muscle actin (aSMA), NF-kB, TNF-a and MMP13 (also known as collagenase-3) were significantly increased in the infarct area of IL-22 KO mice compared to WT mice. Immunostaining showed that the myofibroblast marker aSMA positive cells in the border area after MI were markedly higher in the IL-22 KO mice compared with the WT mice (p<0.05). Approximately 70% of cardiac rupture after MI in the IL-22 KO mice were occurred in the infarct area adjacent to the border area. Furthermore, we found aSMA positive cells and MMP13 positive cells around the ruptured site of the heart.

Conclusion

Thus, IL-22 KO mice exhibit high mortality and increased cardiac rupture after MI. And expression of aSMA and MMP13 were highly expressed in the ruptured site after MI in the IL-22 KO mice. These results suggest that IL-22 may play an important role in the tissue repair process after MI.

Design of a Randomized Controlled Clinical Study of tissue-engineered osteogenic materials using bone marrow-derived mesenchymal cells for Maxillomandibular bone defects in Japan: the TEOM study protocol

Background

Maxillomandibular bone defects arise from maxillofacial injury or tumor/cyst removal. While the standard therapy for bone regeneration is transplantation with autologous bone or artificial bone, these therapies are still unsatisfactory. Autologous bone harvesting is invasive and occasionally absorbed at the implanted site. The artificial bone takes a long time to ossify and it often gets infected. Therefore, we have focused on regenerative therapy consisting of autologous bone marrow-derived mesenchymal cells (BM-MSCs), which decreases the burden on patients. Based on our previous research in patients with maxillomandibular bone defects or alveolar bone atrophy using a mixture of BM-MSCs, platelet-rich plasma (PRP), thrombin, and calcium, we confirmed the efficacy and acceptable safety profile of this treatment. In this investigator-initiated clinical study (the TEOM study), we intended to add β-tricalcium phosphate (β-TCP) owing to large defect with patients. The TEOM study aimed to evaluate the efficacy and safety of bone regeneration using mixtures of BM-MSCs in patients with bone defects resulting from maxillofacial injury, and tumor/cyst removal in the maxillomandibular region.

Methods

The TEOM study is an open-label, single-center, randomized controlled study involving a total of 83 segments by the Fédération Dentaire Internationale numbering system in maxillomandibular bone defects that comprise over 1/3 of the maxillomandibular area with a remaining bone height of ≤10 mm. The primary endpoint is rate of procedure sites with successful bone regeneration defined as a computed tomography (CT) value of more than 400 and a bone height of more than 10 mm. Our specific hypothesis is that the number of required regions was calculated assuming that the rate of procedure sites with successful bone regeneration is similar and the non-inferiority margin is 15.0%.

Discussion

The TEOM study is the first randomized controlled study of regenerative treatment using BM-MSCs for large maxillomandibular bone defects. We will evaluate the efficacy and safety in this study to provide an exploratory basis for the necessity of BM-MSCs for these patients.

Trial registration

This trial was registered at the University Hospital Medical information Network Clinical Trials Registry (UMIN-CTR Unique ID: UMIN000020398; Registration Date: Jan 15, 2016; URL: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000016543).

Kaempferol-immobilized titanium dioxide promotes formation of new bone: effects of loading methods on bone marrow stromal cell differentiation in vivo and in vitro

Background

Surface modification of titanium dioxide (TiO₂) implants promotes bone formation and shortens the osseointegration period. Kaempferol is a flavonoid that has the capacity to promote osteogenic differentiation in bone marrow stromal cells. The aim of this study was to promote bone formation around kaempferol immobilized on TiO₂ implants.

Methods

There were four experimental groups. Alkali-treated TiO₂ samples (implants and discs) were used as a control and immersed in Dulbecco's phosphate-buffered saline (DPBS) (Al-Ti). For the coprecipitation sample (Al-cK), the control samples were immersed in DPBS containing 50 µg kaempferol/100% ethanol. For the adsorption sample (Al-aK), 50 µg kaempferol/100% ethanol was dropped onto control samples. The surface topography of the TiO₂ implants was observed by scanning electron microscopy with energy-dispersive X-ray spectroscopy, and a release assay was performed. For in vitro experiments, rat bone marrow stromal cells (rBMSCs) were cultured on each of the TiO₂ samples to analyze cell proliferation, alkaline phosphatase activity, calcium deposition, and osteogenic differentiation. For in vivo experiments, TiO₂ implants placed on rat femur bones were analyzed for bone-implant contact by histological methods.

Results

Kaempferol was detected on the surface of Al-cK and Al-aK. The results of the in vitro study showed that rBMSCs cultured on Al-cK and Al-aK promoted alkaline phosphatase activity, calcium deposition, and osteogenic differentiation. The in vivo histological analysis revealed that Al-cK and Al-aK stimulated new bone formation around implants.

Conclusion

TiO₂ implant-immobilized kaempferol may be an effective tool for bone regeneration around dental implants.

Mevalonates restore zoledronic acid-induced osteoclastogenesis inhibition

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is likely to be caused by continuous imperfection of bone healing after surgical treatments in patients with long-term administration of nitrogen-containing bisphosphonates (NBPs). NBPs inhibit osteoclastic bone resorption by impairing the mevalonic acid sterol pathway in osteoclasts. Thus, we hypothesized that exogenous mevalonic acid metabolites restore the inhibitory effects of NBPs on osteoclastogenesis and bone remodeling. To clarify the effects of mevalonic acid metabolites, especially geranylgeranyl pyrophosphate (GGPP) and geranylgeranyl transferase substrate geranylgeranyl acid (GGOH), we examined the effects of zoledronic acid with or without GGOH or GGPP on osteoclast differentiation, multinucleation, and bone mineral deposition in tooth-extracted sockets. Zoledronic acid decreased the number of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells derived from mouse osteoclast precursors treated with receptor activator of nuclear factor-κB ligand and macrophage colony-stimulating factor. Zoledronic acid simultaneously suppressed not only the expressions of osteoclastic differentiation-related molecules such as TRAP, cathepsin K, calcitonin receptor, and vacuolar H-ATPase but also those of multinucleation-related molecules such as dendrocyte-expressed 7 transmembrane proteins and osteoclast stimulatory transmembrane protein. Treatment with GGOH or GGPP, but not farnesyl acid, restored the zoledronic acid-inhibited number of TRAP-positive multinuclear cells together with the expressions of these molecules. Although intraperitoneal administration of zoledronic acid and lipopolysaccharide into mice appeared to induce BRONJ-like lesions with empty bone lacunae and decreased mineral deposition in tooth-extracted socket, both GGOH and GGPP partially restored the inhibitory effects on zoledronic acid-related mineral deposition. These results suggest the potential of mevalonic acid metabolites as therapeutic agents for BRONJ.

Hyperocclusion Up-regulates CCL3 Expression in CCL2- and CCR2-deficient Mice

Excessive mechanical stress (MS) during hyperocclusion is known to result in disappearance of the alveolar hard line, enlargement of the periodontal ligament (PDL) space, and destruction of alveolar bone, leading to occlusal traumatism. We have recently reported that MS induces predominantly C-C chemokine ligand (CCL) 2 expression in PDL tissues, leading, via C-C chemokine receptor (CCR) 2, to MS-dependent osteoclastogenesis in alveolar bone. Thus, we hypothesize that ablation of the CCL2/CCR2 signaling pathway should suppress MS-induced osteoclastogenesis-associated chemokines and alleviate occlusal traumatism. We examined the effect of MS on chemokine expression and osteoclastogenesis using in vivo and in vitro hyperocclusion models with CCL2-deficient (CCL2(-/-)) and CCR2-deficient (CCR2(-/-)) mice. Compared with that in wild-type mice, expression of CCL3 in PDL cells and TRAP-positive cells in alveolar bone from CCL2(-/-) and CCR2(-/-) mice was up-regulated, even in the absence of MS. Furthermore, the expression of CCL3 and TRAP-positive cells was significantly increased after both 4 and 7 days of hyperocclusal MS loading in CCL2(-/-) and CCR2(-/-) mice. Hyperocclusion induced compensatory CCL3 expression and promoted osteoclastogenesis to counterbalance deficient CCL2/CCR2 signaling, suggesting that co-expression of CCL3 with CCL2 may precipitate synergistic, MS-dependent alveolar bone destruction during occlusal traumatism. Abbreviations: MS, mechanical stress; PDL, periodontal ligament; CCL2, CC chemokine ligand 2 (MCP-1; monocyte chemoattractant protein-1); CCR2, CC chemokine receptor 2; CCL3, CC chemokine ligand 3 (MIP-1α); CCL5, CC chemokine ligand 5 (RANTES).

Maxillary stability after Le Fort I osteotomy using three different plate systems

The purpose of this study was to compare postoperative changes in maxillary stability after Le Fort I osteotomy in three groups: with an unsintered hydroxyapatite (u-HA)/poly-L-lactic acid (PLLA) plate; a PLLA plate; and a titanium plate. Subjects comprised 60 Japanese patients diagnosed with mandibular prognathism. All patients underwent Le Fort I osteotomy and bilateral sagittal split ramus osteotomy. All patients were randomized in groups of 20 to a u-HA/PLLA group, a PLLA plate group and a titanium plate group. Changes in postoperative time intervals between the plate groups were compared using lateral and posteroanterior cephalography. The uHA/PLLA group had significantly larger values than the PLLA group regarding change of mx1-S perpendicular to SN between 3 and 12 months (T3) (P=0.0269). The uHA/PLLA group had a significantly larger value than the PLLA group regarding change of S-A perpendicular to SN between baseline and 1 month (T1) (P=0.0257). There was no significant difference in the other measurements. This study suggests that maxillary stability with satisfactory results could be obtained in the u-HA/PLLA, PLLA plate and titanium plate groups, although there was a slight difference between the u-HA/PLLA and PLLA plate systems in Le Fort I osteotomy.

Bone regeneration with self-assembling peptide nanofiber scaffolds in tissue engineering for osseointegration of dental implants

The aim of this study was to evaluate the correlation between the osseointegration of dental implants and tissue-engineered bone using a nanofiber scaffold, PuraMatrix (PM). The first molar and all premolars in the mandibular regions of dogs were extracted, and three bone defects were prepared with a trephine bur on both sides of the mandible after 4 weeks. The experimental groups were as follows: (1) PM, (2) PM and dog mesenchymal stem cells (dMSCs), (3) PM, dMSCs, and platelet-rich plasma, and (4) control (defect only). Implants were placed in the prepared areas 8 weeks later and were assessed by histologic and histomorphometric analyses (bone-to-implant contact [BIC]). The BICs for groups 1, 2, 3, and 4 were 40.77%, 50.35%, 55.64%, and 30.57%, respectively. The findings indicate that PM may be useful as a scaffold for bone regeneration around dental implants.

Hyperocclusion Stimulates Osteoclastogenesis via CCL2 Expression

Excessive mechanical stress (MS) during hyperocclusion is known to result in disappearance of the alveolar hard line, enlargement of the periodontal ligament (PDL) space, and destruction of alveolar bone, leading to occlusal traumatism. We hypothesized that MS induces expression of osteoclastogenesis-associated chemokines in PDL tissue, resulting in chemotaxis and osteoclastogenesis during occlusal traumatism. We examined the effect of MS on relationships between chemokine expression and osteoclastogenesis using in vivo and in vitro hyperocclusion models. In an in vitro model, intermittent stretching-induced MS was shown to up-regulate the expression of CC chemokine ligand (CCL)2, CCL3, and CCL5 in PDL cells. The expression levels of CCL2 in PDL tissues, its receptor CCR2 in pre-osteoclasts, and tartrate-resistant acid-phosphatase-positive cells in alveolar bone were significantly up-regulated 4-7 days after excessive MS during hyperocclusion in in vivo rodent models. Hyperocclusion predominantly induced CCL2 expression in PDL tissues and promoted chemotaxis and osteoclastogenesis, leading to MS-dependent alveolar bone destruction during occlusal traumatism. Abbreviations: MS, mechanical stress; PDL, periodontal ligament; CCL2, CC chemokine ligand 2; MCP-1, monocyte chemoattractant protein-1; CCR2, CC chemokine receptor 2; CCL3, CC chemokine ligand 3 (MIP-1α); CCL5, CC chemokine ligand 5 (RANTES); CXCL12, CXC chemokine ligand 12 (SDF-1).

Oral Epithelial Cells are Activated via TRP Channels

Transient receptor potential (TRP) ion channels are critical contributors to the perception of various environmental stimuli. Although the oral cavity is the access point for various food types, the expression of TRP channels in oral mucosa remains unknown. We hypothesized that the oral epithelium itself may participate in sensing thermal, mechanical, and chemical conditions. The expression profiles of TRP channels exhibited regional differences among the buccal, palatal, and tongue epithelia. Changes in elevated intracellular Ca2+ concentration ([Ca2+]i) in oral epithelial cells were found after stimulation of the TRP channels with capsaicin, camphor, 4α-phorbol-12,13 didecanoate (4α-PDD), 2-aminoethoxydiphenyl borate (2-APB), and menthol. These increases in Ca2+ appeared dependent on the TRP channels, because [Ca2+]i suppression was observed after the addition of the TRPV channel antagonist ruthenium red. These results demonstrate that the oral epithelia express various TRP channels and may have functional roles in sensory activities, together with neurons.

Conditional mutualism between Allodynerus delphinalis (Hymenoptera: Vespidae) and Ensliniella parasitica (Astigmata: Winterschmidtiidae) may determine maximum parasitic mite infestation

Mutualism is a prominent interaction within ecosystems, yet most may actually be conditional. The symbiotic mite, Ensliniella parasitica Vitzthum, ingests the hemolymph of juvenile potter wasps, Allodynerus delphinalis (Giraud), but also protects them from a natural enemy, Melittobia acasta, and is transported to new nests in host pockets specialized for this purpose (i.e., acarinaria). Thus, two different antagonisms from the mite may arise: commensalistic cheating is expected without the natural enemy of the host, and parasitism is predicted with excessive numbers of the mite. However, facultative parasitism mediated by mutualism has rarely been studied in any organism. We found no significant differences in juvenile mortality, nesting rate, or fecundity between mite-free and naturally mite-laden juveniles. However, when overloaded with mites ( approximately 1.5-2.5 times more mites than the maximum number per wasp larva in the field), the developmental period of the male wasp was significantly delayed, and juvenile wasp mortality increased to 30%. These results show that mutualism mediated by parasitism may revert to parasitism, suggesting that either or both organisms in a mutualism mediated by parasitism need population control of the parasite to avoid the risk of parasitism.

PTHrP Induces Notch Signaling in Periodontal Ligament Cells

Periodontal ligament (PDL) cells are known to play important roles in tooth eruption and alveolar bone metabolism. We previously reported that PTHrP increases RANKL expression in human PDL cells, suggesting that it promotes odontoclastic root resorption during tooth eruption. While it is known that Notch-related genes play a key role during bone development, the role of the Notch signaling pathway in PDL cells during tooth and bone resorption is less clear. We hypothesized that PTHrP induces a Notch ligand in PDL cells and thereby regulates osteo- and odontoclastogenesis. We found that PTHrP increased Notch1 ligand Jagged1 expression in human PDL cells in a dose- and time-dependent manner. PTHrP-induced Jagged1 up-regulation was mediated by PKA activation, but not by PKC. Jagged1 also promoted RANKL-induced osteoclastogenesis. These results demonstrate that PTHrP induces Jagged1 expression in PDL cells, leading to osteo- and odontoclastogenesis, and thus likely promoting tooth and alveolar bone resorption.

[Malignant pleural mesothelioma in which many asbestos bodies were counted in its specimen]

A 53-years-old woman was admitted to our hospital because of pleural effusion. She underwent pleural biopsy and diagnosed as mesothelioma. Right extrapleuralpneumonectomy was performed. We counted asbestos bodies in the resected lung. 443,571 asbestos bodies were counted in 1 gram of dry lung. We thought that she was heavily exposed to asbestos. Since high risk of incidence of mesothelioma is suggested among her fellow worker, special investigation is necessary for asbestos exposure.

The effects of changing position and angle of the proximal segment after intraoral vertical ramus osteotomy

The authors evaluated changes in position and angle of the proximal segment, including the condyle, after intraoral vertical ramus osteotomy (IVRO) with and without a Le Fort I osteotomy to verify whether displacement of the proximal segment could induce postoperative complications. Changes in condylar angle, ramus angle, and displacement of proximal segment were measured pre- and postoperatively. The position of the temporomandibular joint (TMJ) disc was examined pre- and postoperatively. Trigeminal nerve hypoesthesia in the lower lip was assessed bilaterally. The postoperative horizontal condylar angle was significantly smaller than the preoperative one on the deviated and non-deviated sides (P<0.0001). The postoperative coronal condylar angle was significantly larger than the preoperative one on the deviated side (P=0.0483). The postoperative sagittal ramus angle was larger than the preoperative one on the deviated (P<0.0001) and non-deviated (P=0.00005) side. Most joints with an anteriorly-displaced disc with and without reduction improved on the non-deviated side; 5 of 16 joints improved on the deviated side. Results suggest the position and angle of the proximal segment, including the condyle, could change after IVRO. This could be associated with symptomatic improvement in TMJ, and extreme medial displacement of the proximal segment could delay recovery from lower lip hypoesthesia.

[Video-assisted thoracic surgery (VATS) for clinical stage I lung cancer in consideration of the diameters and characteristcs of each tumor and the technical limitations of VATS]

We planned an intervention study to investigate the late outcome of limited surgery for cStage IA lung cancer by several video-assisted thoracic surgery (VATS) procedures.

METHODS

VATS partial resection was done for non-solid tumors less than 1.5 cm in maximum diameter with non-solid component on high resolution computed tomography (HRCT) [group A]. VATS segmentectomy with minor thoracotomy with ND1 + alpha lymph node dissection was done for tumors less than 2.0 cm in maximum diameter that was not included in the group A (group B). Tumors of less than 3.0 cm in diameter that did not fit into the other 2 groups were treated by VATS lobectomy with minor thoracotomy plus ND2 lymph node dissection (group C).

RESULTS

A total of 159 patients were enrolled during the 5-year enrollment period (group A: 21 patients, group B: 43 patients, group C: 95 patients). The recurrence-free 5-year survival rate was 100% in the group A, 82.8% in the group B, and 78.4% in the group C, showing no significant differences between the groups. Twenty-eight % of patients was switched to surgical techniques involving more extensive resection in the group A and B. while 6% of the patients was switched to thoracotomy overall. The overall recurrence rate was 10.7% (n=17), while the locoregional and distant recurrence rate was 5.7% (n=9) and 5.0% (n=8), respectively.

CONCLUSIONS

This controlled intervention study suggested that limited surgery by VATS approaches for cStage IA lung cancer are acceptable as cancer operation.

Involvement of tazarotene-induced gene 1 in proliferation and differentiation of human adipose tissue-derived mesenchymal stem cells

OBJECTIVE

Mesenchymal stem cells (MSC) have both self-renewal and multilineage differentiation potential, and bone marrow-derived MSC have been applied for tissue regeneration and repair. Although adipose tissue-derived MSC (ASC) have emerged as an alternative cell source, little information is available regarding the biologic difference between ASC derived from visceral and subcutaneous fat. Therefore, we aimed to compare the proliferation and gene expression profile of cultured human visceral ASC (VASC) and subcutaneous ASC (SASC), and to identify a novel gene involved in proliferation and differentiation of ASC.

MATERIALS AND METHODS

We performed microarray analysis of cultured VASC and SASC, and investigated the role of tazarotene-induced gene 1 (TIG1), a most differentially expressed gene, in the proliferation and differentiation of ASC.

RESULTS

SASC proliferated faster than VASC for over 10 passages, and TIG1 expression was consistently up-regulated in VASC of humans, rats and mice. Overexpression of the TIG1 gene in human SASC inhibited cell proliferation, whereas knockdown of TIG1 expression by siRNA promoted cell proliferation. In addition, overexpression of the TIG1 gene in SASC enhanced their differentiation into adipocytes, and promoted up-regulation of peroxisome proliferators-activated receptor gamma and CCAAT/enhancer binding protein alpha. On the other hand, TIG1 overexpression in SASC inhibited their differentiation into osteocytes and the expression of osteocalcin.

CONCLUSION

TIG1 plays an important role in regulating proliferation and differentiation of ASC.

[Granulocyte-colony stimulating factor producing tumor with high serum interleukin-6]

A 53-year-old man admitted to our hospital because of fever and chest abnormal shadow. Chest X-ray and computed tomography (CT) scan revealed large tumor on right upper lobe. Serum interleukin (IL)-6 and granulocyte-colony stimulating factor (G-CSF) were high. Right upper lobectomy and chest wall resection was performed. Histological diagnosis was large cell carcinoma. Immunohistological examination of lung tumor cells showed positive staining for G-CSF in only 1% of them. We diagnosed that tumor was G-CSF producing tumor and we thought that tumor produced IL-6.