Anti-USAG-1 therapy for tooth regeneration through enhanced BMP signaling

Uterine sensitization-associated gene-1 (USAG-1) deficiency leads to enhanced bone morphogenetic protein (BMP) signaling, leading to supernumerary teeth formation. Furthermore, antibodies interfering with binding of USAG-1 to BMP, but not lipoprotein receptor-related protein 5/6 (LRP5/6), accelerate tooth development. Since USAG-1 inhibits Wnt and BMP signals, the essential factors for tooth development, via direct binding to BMP and Wnt coreceptor LRP5/6, we hypothesized that USAG-1 plays key regulatory roles in suppressing tooth development. However, the involvement of USAG-1 in various types of congenital tooth agenesis remains unknown. Here, we show that blocking USAG-1 function through USAG-1 knockout or anti-USAG-1 antibody administration relieves congenital tooth agenesis caused by various genetic abnormalities in mice. Our results demonstrate that USAG-1 controls the number of teeth by inhibiting development of potential tooth germs in wild-type or mutant mice missing teeth. Anti-USAG-1 antibody administration is, therefore, a promising approach for tooth regeneration therapy.

Promotion in solid phase reaction of Pt/SiOx bilayer film by electron-orbital-selective-excitation

A thermally impossible positive free energy reaction can proceed by electron-orbital-selective excitation. When the Si 2p core level is photo-excited in Pt/SiO_x bilayer films, Coulomb repulsion at the final two-hole state localized in the valence band by an interatomic Auger transition induces dissociation of the O atom and formation of a Si–Pt bond. Consequently, Pt₂Si silicide is formed by a positive free energy reaction. Under a single particle excitation of the valence band, low probability of the coexistence of the two-hole state for picosecond order suppresses to allow the reaction to proceed.

A thermally impossible positive free energy reaction can proceed by electron-orbital-selective excitation.

REACTOR PHYSICS EXPERIMENT IN A GRAPHITE-MODERATION SYSTEM FOR HTGR

The Japan Atomic Energy Agency (JAEA) started the Research and Development (R&D) to improve nuclear prediction techniques for High Temperature Gas-cooled Reactors (HTGRs). The objectives are to introduce a generalized bias factor method to avoid full mock-up experiment for the first commercial HTGR and to introduce reactor noise analysis to High Temperature Engineering Test Reactor (HTTR) experiment to observe sub-criticality. To achieve the objectives, the reactor core of graphite-moderation system named B7/4”G2/8”p8EUNU+3/8”p38EU(1) was newly composed in the B-rack of Kyoto University Critical Assembly (KUCA). The core is composed of the fuel assembly, driver fuel assembly, graphite reflector, and polyethylene reflector. The fuel assembly is composed of enriched uranium plate, natural uranium plate and graphite plates to realize the average fuel enrichment of HTTR and it’s spectrum. However, driver fuel assembly is necessary to achieve the criticality with the small-sized core. The core plays a role of the reference core of the bias factor method, and the reactor noise was measured to develop the noise analysis scheme. In this study, the overview of the criticality experiments is reported. The reactor configuration with graphite moderation system is rare case in the KUCA experiments, and this experiment is expected to contribute not only for an HTGR development but also for other types of a reactor in the graphite moderation system such as a molten salt reactor development.

Erlotinib plus bevacizumab vs erlotinib monotherapy as first-line treatment for advanced EGFR mutation-positive non-squamous non-small-cell lung cancer: Survival follow-up results of the randomized JO25567 study

OBJECTIVES

The JO25567 randomized Phase II study demonstrated a statistically significant progression-free survival (PFS) benefit with erlotinib plus bevacizumab compared with erlotinib monotherapy in chemotherapy-naïve Japanese patients with epidermal growth factor receptor mutation-positive (EGFR+) non-small-cell lung cancer (NSCLC). Here we present updated PFS and final overall survival (OS) data after a median follow-up of 34.7 months.

MATERIALS AND METHODS

Patients with stage IIIB/IV or postoperative recurrent NSCLC were randomized to receive oral erlotinib 150 mg once daily (n = 77) or erlotinib in combination with intravenous bevacizumab 15 mg/kg every 21 days (n = 75) until disease progression or unacceptable toxicity. OS was analyzed using an unstratified Cox proportional hazards model.

RESULTS

Consistent with the primary analysis, addition of bevacizumab to erlotinib was associated with a significant improvement in PFS (hazard ratio [HR] 0.52; 95 % confidence interval [CI]: 0.35-0.76; log-rank two-sided P = 0.0005; median 16.4 months vs 9.8 months, respectively). In contrast, a significant improvement in OS was not seen (HR 0.81; 95 % CI, 0.53-1.23; P =  0.3267; median 47.0 months vs 47.4 months, respectively). Post-study therapy was similar between the treatment arms and EGFR mutation type did not affect OS outcomes. The 5-year OS rate was numerically higher with erlotinib plus bevacizumab vs erlotinib monotherapy (41 % vs 35 %). Updated safety analyses confirmed the previously reported manageable tolerability profile, with no new safety issues.

CONCLUSION

Addition of bevacizumab to first-line erlotinib did not show significant improvement in OS in Japanese patients with stage IIIB/IV or postoperative recurrent EGFR+ NSCLC. Both treatment arms showed a similar median OS benefit (as long as 4 years), irrespective of individual patient characteristics. Results from ongoing studies evaluating the combination of EGFR and VEGF signaling inhibitors are eagerly awaited.

TRIAL REGISTRATION

JapicCTI-111390 and JapicCTI-142569.

Ten-year all-cause death after percutaneous or surgical revascularization for men and women with multivessel or left main coronary artery disease: insights from the SYNTAX extended survival study

Background

In patients with complex coronary artery disease (CAD), women favored coronary artery bypass grafting surgery (CABG) compared to percutaneous coronary intervention (PCI) at 5 years in the SYNTAX trial, whereas mortality rates after PCI and CABG were not different in men. On the other hand, poor outcomes of women undergoing PCI were not observed in the PRECOMBAT and BEST trials.

The long-term optimal revascularization strategy according to gender has not been fully evaluated.

Purpose

In the SYNTAX Extended Survival (SYNTAXES) study, no significant difference existed in all-cause death between PCI and CABG at 10 years. This study aimed to assess treatment effect of PCI and CABG for 10-year all-cause death according to gender.

Methods

The SYNTAXES study evaluated vital status up to 10 years in 1,800 patients with de novo three-vessel disease (3VD) and/or left main coronary artery disease (LMCAD) randomized to treatment with CABG or PCI in the SYNTAX trial, and the pre-specified primary endpoint was all-cause death at 10 years. In this prespecified analysis, all-cause death at 10 years according to gender in patients undergoing PCI or CABG was evaluated.

Results

Of 1800 patients, 402 (22.3%) were women and 1398 (77.7%) were men. In women, the rate of mortality was significantly higher in the PCI arm at 5 years than in the CABG arm (19.3% vs. 10.3%; Log-rank p=0.010, Figure A), but the rates of mortality were not different at 10 years between the PCI and CABG arms (33.0% vs. 32.5%; Log-rank p=0.600, Figure A). In men, the mortality rate tended to be higher in the PCI arm at 10 years than in the CABG arm (27.0% vs. 22.5%; Log-rank p=0.082, Figure B), although the mortality rates were not different at 5 years between the PCI and CABG arms (12.4% vs. 12.3%; Log-rank p=0.957, Figure B).

Conclusion

The efficacy of CABG observed at 5 years disappeared at 10 years in women, whereas the efficacy of CABG became apparent after 5 years in men.

Figure 1

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Erasmus University Medical Centre, Rotterdam, Netherlands, reference: MEC-2016-716

Effects of smoking cessation on endothelial function assessed by flow-mediated dilation and reactive hyperemia peripheral artery tonometry

Background

Smoking predisposes individuals to endothelial dysfunction. Both flow-mediated dilation (FMD) and reactive hyperemia peripheral artery tonometry (RH-PAT) are used to assess endothelial function. However, there are differences in the physiology of vascular beds being tested and in the response of conduit and resistive vessels to RH. Therefore, whether smoking cessation demonstrates comparable effects on endothelial function evaluated by FMD and by RH-PAT remains unclear.

Purpose

We aimed to evaluate the effects of smoking cessation on endothelial function evaluated simultaneously by FMD and RH-PAT.

Methods

Thirty-eight consecutive current smokers (mean±standard deviation; age, 65±10 years) who visited our smoking cessation outpatient department and succeeded in smoking cessation with varenicline were enrolled. Clinical variables, FMD, and natural logarithmic transformation of the reactive hyperemia index (Ln-RHI) were examined before and 20 weeks after treatment initiation. Fifteen current smokers who failed in smoking cessation were enrolled as age- and sex-matched controls. The Spearman's rank correlation coefficient and intraclass correlation coefficient (ICC) for a two-way mixed effects model were performed to assess the agreement of changes in FMD and Ln-RHI. Multivariate logistic regression analysis was performed to examine the associations between the presence of increase in FMD or Ln-RHI and clinical variables.

Results

FMD significantly improved after smoking cessation (3.42%±1.96% to 4.45%±2.28%; p=0.019), whereas Ln-RHI did not (0.53±0.25 to 0.59±0.21; p=0.223). The Spearman's rank correlation coefficient between changes in FMD and Ln-RHI was −0.013, and the ICC was −0.002 (p=0.506). In the multivariate logistic regression analysis, an increase in FMD or Ln-RHI was predicted based on the baseline FMD (odds ratio = 0.54, p=0.013) or Ln-RHI (odds ratio = 0.36, p=0.012), respectively, after adjusting for age and sex.

Conclusions

There was significant improvement in the endothelial function assessed by FMD, but not by Ln-RHI, after smoking cessation. In addition, there was disagreement between changes in FMD and those in Ln-RHI. Smoking cessation may have varying effects on the endothelial function of the conduit and digital vessels.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-aid for scientific research from the ministry of education, science and culture of Japan

Clinical significance of controlling nutritional status score for predicting short-term clinical events in takotsubo syndrome: a multicenter study

Background

The Controlling Nutritional Status (CONUT) score is well known as a marker of nutritional status. Previous studies have reported that CONUT score could predict a prognosis of acute or chronic heart failure, and infective endocarditis. Takotsubo syndrome (TTS) is said to have a relatively good prognosis, but some patients have a bad turning point in hospital stay. Lower systolic blood pressure on admission, history of diabetes mellitus, and β-blocker use before admission have been reported as predictors of in-hospital cardiac complications. However, the prognostic utility of CONUT score in TTS is unclear. The aim of study was to evaluate duration of hospital stay and short-term clinical events with CONUT score in TTS.

Methods

Seventy-nine TTS patients who were admitted to 3 medical centers in Japan between January 2011 and October 2019 were enrolled. The average age was 71.8±11.5 years old, and the prevalence of female sex was 81%. The CONUT score was calculated based on the serum albumin, total lymphocyte and total cholesterol on admission. We retrospectively investigated the association between the short-term clinical events and CONUT score. The duration of hospital stay was defined as the primely outcome, and all cause death and congestive heart failure in hospital stay as the secondary outcome.

Results

The average CONUT score was 3.7±3.0. A positive correlation was found between the CONUT score and the duration of hospital stay (r=0.56, p<0.01). Twenty (25.3%) patients suffered from clinical events (all cause death and congestive heart failure in hospital). Those patients with clinical events had significantly higher the CONUT score than those without (all cause death, 7.2±2.6 vs. 3.5±2.9, p<0.01, congestive heart failure, 5.3±3.4 vs. 3.3±2.8, p=0.02, composite clinical events, 5.8±3.2 vs. 3.0±2.6, p<0.01). ROC curve analysis revealed that the optimal cut-off value of the CONUT score for the prediction of composite clinical events was 4.0 (AUC: 0.75, sensitivity: 80%, Specificity: 64%). The patients with CONUT score of 4 or more (high COUNT score) were more prevalent in patients who experienced composite clinical events than in those who didn't (80% vs. 35.6%, p<0.01). The patients with a high CONUT score had a longer hospital stay and higher occurrence of composite clinical events than those with CONUT score less than 4 (respectively, 27.2±19.1 days vs. 13.8±8.3 days, p<0.01, 25.3% vs. 9.5%, p<0.01).

Conclusions

The CONUT score in TTS patients was strongly associated with the duration of hospital stay and clinical events in hospital. The CONUT score is a simple indicator that can be calculated with only three factors. Therefore, the CONUT score on admission may be useful for a predictor of short-term clinical events in TTS patients.

Funding Acknowledgement

Type of funding source: None

Treatment of complex coronary artery disease in patients with diabetes mellitus and chronic kidney disease: 10-year results comparing outcomes of CABG and PCI in the SYNTAXES trial

Background

The SYNTAX Extended Survival (SYNTAXES) study is an investigator-driven extension of follow-up of the SYNTAX trial, which was a non-inferiority trial that compared percutaneous coronary intervention (PCI) using first-generation paclitaxel-eluting stents with coronary artery bypass grafting (CABG) in patients with de-novo three-vessel and left main coronary artery disease. The SYNTAXES study is the first randomized trial that reported the complete 10-year data on all-cause death in patients with complex coronary artery disease.

Purpose

Patients with coronary artery disease (CAD) and concomitant diabetes mellitus (DM) or chronic kidney disease (CKD) are more susceptible to major adverse cardiovascular and cerebrovascular events. However, to date, the long-term prognosis and which revascularization strategy was associated with better clinical outcomes for patients with complex coronary artery disease and concomitant with DM and CKD have not been documented.

Methods

In this sub-analysis of the SYNTAXES trial, a total of 1,638 patients were classified into four subgroups according to the DM and CKD status: DM−/CKD− (n=999, 60.1%), DM+/CKD− (n=323, 19.7%), DM−/CKD+ (n=231, 14.1%), and DM+/CKD+ (n=85, 5.2%). The treatment effects of PCI and CABG were analyzed in each subgroup. The primary endpoint was all-cause death at 10 years.

Results

Compared with the DM−/CKD− patients, patients with DM+/CKD+ were older, more often had a history of stroke, hypertension, heart failure, and were more frequently presented with total occlusion, bifurcation lesion and three-vessel disease. At 10 years, patients with DM+/CKD+ had a 3.94-fold higher incidence of all-cause mortality compared with DM−/CKD− individuals (54.1% versus 18.9%, 95% CI [2.85–5.44]). Patients with DM−/CKD+ (38.1%, HR 2.36; 95% CI [1.83–5.44]) or DM+/CKD− (28.2%, HR 1.61; 95% CI [1.26–2.07]) had intermediate risk profile. For DM+/CKD+ patients, compared with PCI, those who underwent CABG were associated with lower incidence of all-cause mortality (64.3% versus 44.2%, adjusted HR 0.52; 95% CI [0.27–0.99], p=0.047, pinteraction=0.443). The number of needed-to-treat to reduce mortality for CABG was 12.

Conclusion

In the SYNTAX population, patients with DM and CKD are at markedly increased risk of long-term mortality rate compared with patients one or neither of these risk factors. For patients with both comorbidities, CABG was associated with better clinical outcome compared with PCI. These findings should be interpreted as hypothesis-generating.

Figure 1. Kaplan-Meier curves showing the clinical events according to treatment and DM/CKD status.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Boston Scientific Corporation

Impact of periprocedural myocardial infarction on 10-year mortality after percutaneous coronary intervention or coronary artery bypass grafting for multivessel or left main coronary artery disease

Background

Periprocedural myocardial infarction (PMI) occurs frequently after both percutaneous coronary intervention (PCI) and bypass grafting surgery (CABG) in patients with complex coronary artery disease (CAD), and PMI has been shown to have a detrimental impact on mortality. On the other hand, long-term impact of PMI on mortality has not been fully evaluated.

Purpose

This study aimed to assess the impact of PMI according to SCAI definition on 10-year all-cause death in patients with complex CAD.

Methods

The SYNTAX Extended Survival (SYNTAXES) study evaluated vital status up to 10 years in 1800 patients with de novo three-vessel disease and/or left main coronary artery disease randomized to treatment with CABG or PCI in the SYNTAX trial. Blood was sampled for creatine kinase (CK) pre- and post-revascularisation, and the cardiac specific MB iso-enzyme (CK-MB) was determined only if the CK ratio ≥2 x the upper limit of normal (ULN). If the CK ratio <2 ULN, CK-MB assessment was not mandated. In this analysis, patients with at least one blood sampling within 48 hours of the procedure were included. PMI was defined as follows; peak CK-MB measured within 48 hours of the procedure ≥10 x ULN, or ≥5 x ULN with new Q-waves in 2 contiguous leads or new persistent left bundle branch block.

Results

Of 1800 patients, 1679 (93.2%) patients were included. Of 877 patients treated with PCI, PMI occurred in 26 patients (3.0%), whereas 14 (1.7%) PMIs were observed in 802 patients treated with CABG. Compared with patients without PMI, patients with PMI presented with unstable angina more frequently (45.0% vs. 28.7, p=0.033), and had a higher rate of bifurcation lesion (87.5% vs. 72.5, p=0.046). PMI was associated with a higher all-cause mortality at 10 years compared with no PMI (55.3% vs. 25.4%; Log-rank p<0.001, Figure), which was mainly driven by a high mortality rate within 1 year. In patients undergoing PCI, the mortality rates were significantly higher in patients with PMI not only within 1 year (Log-rank p<0.001) but also beyond one year (Log-rank p=0.016), compare to patients without PMI (Figure). On the other hand, in patients undergoing CABG, a higher mortality rate in patients with PMI was observed until 1 year (Log-rank p<0.001), but the impact of PMI on mortality beyond one year after CABG subsided (Log-rank p=0.308) (Figure 1).

Conclusion

PMI was associated with a poor prognosis at 10 years. The impact of PMI on mortality was strong within one year. Of note, the impact of PMI on mortality persisted beyond 1 year only in patients undergoing PCI. Patients who were treated with PCI and suffered PMI need careful follow-up beyond one year after revascularization.

Figure 1

Funding Acknowledgement

Type of funding source: None

Ten-year all-cause death in elderly patients undergoing percutaneous coronary intervention or coronary artery bypass grafting: a prespecified subgroup analysis of the SYNTAX Extended Survival study

Background

Coronary artery disease is the leading cause of death among elderly men and women worldwide. The aging society worldwide will lead to increasing numbers of elderly patients with multivessel coronary artery disease. Although age is recognized as one of the most important factors in a decision-making for revascularization of multivessel coronary artery disease, the very long-term outcomes in patients undergoing revascularization by percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) is still unclear.

Objectives

The aim of the present study was to investigate the association between revascularization strategies and 10-year outcomes in elderly patients.

Methods

The SYNTAX Extended Survival (SYNTAXES) study (NCT 03417050) is an investigator-driven extension of follow-up of a multicentre, randomised controlled trial done in 85 hospitals across 18 North American and European countries, enrolling 1,800 patients with de novo three-vessel disease (3VD) and/or left main coronary artery disease (LMCAD) randomized to revascularization strategy with CABG versus PCI in the SYNTAX trial. Patients were divided into two groups according to the prespecified threshold of 70 years old; elderly patients (>70 years) and non-elderly patients (≤70 years). The primary endpoint of this study was all-cause death at 10 years.

Results

Out of 1,800 patients, 575 patients (31.9%) were classified as elderly (>70 years). The mean age ± standard deviation (SD) of the elderly patients and the non-elderly patients was 75.8±3.6 years and 60.1±7.4 years, respectively. Of note, elderly patients were more frequently female than non-elderly patients (33.6% vs. 17.1%, p<0.001). As expected, the elderly patients had higher prevalence of chronic kidney disease (43.4% vs. 7.9%, p<0.001), had higher anatomical SYNTAX score (30.2±11.8 vs 28.0±11.2 p<0.001) when compared to those of the non-elderly patients.

Up to 10 years, all-cause death occurred in 42.7% and 18.9% in the elderly and non-elderly patients, respectively (Log-rank p<0.001). The cubic spline curve showed an exponentially increase in all-cause death at 10 years according to the increase of age both in the PCI arm and the CABG arm. At 10 years, there was no significant difference in the risk of all-cause death between CABG vs. PCI either in elderly patients (41.5% vs. 44.0%; Log-rank p=0.53) or non-elderly patients (16.6% vs. 21.1%; Log-rank p=0.051).

Conclusion

CABG and PCI were equipoise in terms of risk of all-cause death at 10 years in patients with de novo 3VD and/or LMCAD irrespective of their age when stratified according to the prespecified threshold of 70 years old.

Kaplan-Meier curves

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): German Foundation of Heart Research

Frailty Checkup Supporters' Intentions to Participate in Human-Resource Development and Training Activities

BACKGROUND

Frailty prevention is one of social prescriptions for an aging society. That requires community level intervention.

OBJECTIVES

This study examined frailty checkup supporters' (FCSs') intentions to engage in human-resource development and training activities (i.e., leadership activities) and related factors.

DESIGN

Cross-sectional study.

SETTING

Three municipalities in suburban area, Eastern Japan.

PARTICIPANTS

Forty-five of 59 FCSs completed anonymous self-administered questionnaires.

MEASUREMENTS

Questionnaire sought information regarding their sociodemographic data, their perceptions and experiences of FCS activities, and their intentions to participate in human-resource development and training activities. Participants were divided into a high intention (HI) and low intention group (LI). The two groups were compared using quantitative and qualitative data.

RESULTS

Eleven FCSs reported intending to engage in leader-related activities. Factors associated with FCSs' intentions were finding FCS activities rewarding and the willingness to continue performing FCS activities. The participants who changed their daily activities (p = .041) and perceptions regarding contributing to the community (p = .018) showed significantly higher intention than LI participants. Free description about the changes in perceptions and lifestyles as a consequence of participating in FCS activities were analyzed qualitatively. FCSs who changed their daily activities and perspectives about contributing to the community described positive changes in both the groups. Meanwhile, FCSs who did not change their daily activities and perspectives about contributing to the community described their reason only in the LI group.

CONCLUSIONS

The results might encourage FCSs to participate in training and guidance activities, as they have positive experiences and receive recognition obtained through participation in such activities.

Abstract 135: Increased expression of ganglioside GM2 correlates with aggressiveness of human pancreatic ductal adenocarcinoma

(a) Purpose: Gangliosides are molecules composed of glycosphingolipids linked with one or more sialic acids, and are known to be key components of lipid rafts, which act as platforms for signal transduction. Changes in ganglioside levels affect the expression of raft-associated proteins on the cell surface and lead to reduced membrane fluidity, thus, resulting in cellular dysfunction, such as impaired signal transduction. The ganglioside GM2 is one of the major series of gangliosides that has several biological functions, such as in cell adhesion and signal transduction. GM2 is highly expressed in several types of human malignant tumors, such as melanomas, gliomas, and neuroblastomas, but is absent or weakly expressed in normal tissues. However, the association between gangliosides and pancreatic ductal adenocarcinoma (PDAC) has not been elucidated yet. Thus, in this study, we aimed to clarify the expression and role of ganglioside GM2 in PDAC.

(b) Experimental procedures: GM2 expression in eight human PDAC cell lines was examined by fluorescence-activated cell sorter (FACS) analysis. The morphology, growth, and stemness of GM2- and GM2+ sorted-cells were compared by transmission electron microscopy, growth assays, real-time PCR analysis of the markers of stemness, and sphere forming assays. Cell motility was evaluated by invasion assay. For comparing tumorigenicity between the GM2- and GM2+ sorted-cells, heterotopic implantations were performed. The expression levels and clinico-pathological roles of GM2 in patients with PDAC were examined by immunohistochemical analysis of 117 pancreatic tissue samples.

(c) Results: The fraction of GM2+ cells was the highest (21.4%) in MIA PaCa-2 from among the eight cell lines, as revealed by FACS analysis. GM2-expressing MIA PaCa-2 cells had higher growth rates under adherent growth conditions. In 3D-culture, which enriches cancer stem cells (CSCs), most MIA PaCa-2 cells expressed GM2 and the cells responded to TGF-β1 treatment to promote invasion. Transplantation of the GM2-expressing cells into nude mice resulted in development of larger tumors as compared to that for control cells that did not express GM2. In the PDAC cases, GM2 expression was significantly associated with younger age, larger tumor size, advanced stage, and higher histological grade.

(d) Conclusions: We show that a PDAC cell line overexpressing GM2 exhibits high growth rate and high tumor initiation in 2D-culture. Further, pancreatic CSC-like cells expressing GM2 exhibit responsiveness against TGF-β1, resulting in enhanced invasion in 3D-culture. Furthermore, GM2 expression is associated with the growth and advanced stage of human PDAC. Further studies will be required for the development of an early detection method for GM2-overexpressing pancreatic cancers and to develop novel therapeutic strategies targeting GM2.

Citation Format: Norihiko Sasaki, Kenichi Hirabayashi, Masaki Michishita, Kimimasa Takahashi, Fumio Hasegawa, Fujiya Gomi, Yoko Itakura, Naoya Nakamura, Masashi Toyoda, Toshiyuki Ishiwata. Increased expression of ganglioside GM2 correlates with aggressiveness of human pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 135.

Reduction of extracellular sodium evokes nociceptive behaviors in the chicken via activation of TRPV1

Transient receptor potential vanilloid 1 (TRPV1), a non-selective cation channel, is mainly expressed in nociceptive primary sensory neurons. Sensitivity of TRPV1 to several stimuli is known to vary among species, specifically, the avian orthologue is nearly insensitive to capsaicin. Extracellular sodium ions ([Na⁺]_o) regulate TRPV1 activity in mammals, but their regulatory role on chicken TRPV1 (cTRPV1) is unknown. Here, we focused on the actions of capsaicin and low [Na⁺]_o on cTRPV1 activity. In chicken dorsal root ganglion (cDRG) neurons, capsaicin elicited [Ca²⁺]_i increases, but its effective concentration was much higher than those in mammals. Low [Na⁺]_o evoked [Ca²⁺]_i increases in cDRG neurons in a decreasing [Na⁺]_o-dependent manner and the complete removal of [Na⁺]_o (0Na) produced maximal effects. The population of 0Na-sensitive neurons was mostly overlapped with those of proton- and capsaicin-sensitive ones. Low [Na⁺]_o synergistically potentiated the capsaicin- and proton-induced TRPV1 activation in cDRG neurons. In HEK293 cells expressing cTRPV1 (cTRPV1-HEK), capsaicin elicited [Ca²⁺]_i increases with an EC₅₀ of 11.8 µM, and low [Na⁺]_o also did. Well-defined mammalian TRPV1 antagonists hardly suppressed cTRPV1 activation by low [Na⁺]_o. 0Na evoked outwardly rectified currents in cTRPV1-HEK. Mutagenesis analyses revealed a possible interaction of [Na⁺]_o with the proton-binding sites of cTRPV1. The administration of capsaicin and 0Na to chick eyes elicited pain-related behaviors. These results suggest that low [Na⁺]_o is capable of activating cTRPV1 in vitro, resulting in pain in vivo. Our data demonstrate that characterization of the cTRPV1 function is important to understand activation mechanisms of TRPV1.

Neuropathology in Neonatal Mice After Experimental Coxsackievirus B2 Infection Using a Prototype Strain, Ohio-1

Coxsackievirus B (CVB) causes severe morbidity and mortality in neonates and is sometimes associated with severe brain damage resulting from acute severe viral encephalomyelitis. However, the neuropathology of CVB infection remains unclear. A prototype strain of coxsackievirus B2 (Ohio-1) induces brain lesions in neonatal mice, resulting in dome-shaped heads, ventriculomegaly, and loss of the cerebral cortex. Here, we characterized the glial pathology in this mouse model. Magnetic resonance imaging revealed an absence of the cerebral cortex within 2 weeks after inoculation. Histopathology showed that virus replication triggered activation of microglia and astrocytes, and induced apoptosis in the cortex, with severe necrosis and lateral ventricular dilation. In contrast, the brainstem and cerebellum remained morphologically intact. Immunohistochemistry revealed high expression of the coxsackievirus and adenovirus receptor (a primary receptor for CVB) in mature neurons of the cortex, hippocampus, thalamus, and midbrain, demonstrating CVB2 infection of mature neurons in these areas. However, apoptosis and neuroinflammation from activated microglia and astrocytes differed in thalamic and cortical areas. Viral antigens were retained in the brains of animals in the convalescence phase with seroconversion. This animal model will contribute to a better understanding of the neuropathology of CVB infection.

Effect of lactate administration on exercise-induced PGC-1α mRNA expression in Thoroughbreds

The aim of this study was to examine the effects of lactate administration on the mRNA response of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) to acute exercise in Thoroughbred skeletal muscle. Five Thoroughbred horses performed treadmill running at 90% of maximal oxygen consumption for 2 min on two separate occasions, either after the administration of two litres of a sodium lactate solution (LAC; 500 mmol/l sodium lactate in 0.9% NaCl) or a saline solution as a control (CON; 0.9% NaCl). Lactate administration significantly elevated the peak plasma lactate concentration during exercise (16.0±2.8 mmol/l in LAC vs 10.8±2.2 mmol/l in CON). The increase in PGC-1α mRNA expression after 4 h of recovery from exercise was similar between treatments. However, there was positive correlation between exercise-induced PGC-1α mRNA response at 4 h after exercise and peak plasma lactate concentration during exercise. These results suggest that the exercise intensity-dependent adaptation of PGC-1α may be attributed, at least in part, to an increased lactate concentration.