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

OP0128 DISTINCT FEATURES OF HLA-DR+ AND HLA-DR- PD-1HI CXCR5- T PERIPHERAL HELPER CELLS IN SEROPOSITIVE RHEUMATOID ARTHRITIS

Background:

PD-1hi CXCR5- T peripheral helper (Tph) cells are newly identified pathogenic CD4+ helper T cells in rheumatoid arthritis (RA). Since Tph cells have been emerged quite recently, the characteristics of Tph cells as a biomarker of RA are not fully understood.

Objectives:

The aim of the study is to evaluate how useful Tph cells in peripheral bloods are when compared to other immune cell subsets, and to clarify which Tph subset most accurately reflects the disease activity of RA.

Methods:

The RA patients who visited our rheumatology department between January 2000 and February 2017, and met the 2010 ACR/European League Against Rheumatism (EULAR) classification criteria were included. We first assessed correlation with 40 immune cell subsets and the disease activity of RA. Next, the proportions of these immune cells were compared between RA and healthy controls (HCs). We also investigated the immune cell subsets which reflected the time course change of the disease activity after the methotrexate (MTX) treatment. The study protocol was approved by the ethics committee at Keio University School of Medicine.

Results:

Thirty-four seropositive RA, 12 seronegative RA and 34 HCs were included. The Immune cell subsets which showed correlation with DAS28-ESR (r> 0.2 or r> -0.2) were activated CD4 T cells (r= 0.31), HLA-DR+Th1 cells (r= 0.20), HLA-DR+Th1-17 cells (r= 0.25), Tfh1-17 cells (r= -0.25), HLA-DR+Tph cells (r= 0.22), CD3+CD8+naïve T cells (r= -0.25), CD3+CD8+effector memory T cells (r= -0.26), plasma cells (r= 0.40) and CD14++CD16+intermediate monocyte (r= 0.23). The proportions of HLA-DR+Th1 cells (2.3% vs. 5.7%), HLA-DR+Th1-17 cells (0.7% vs. 2.2%), Tfh1-17 cells (1.7% vs. 2.0%), HLA-DR+Tph cells (0.02% vs. 0.1%), CD3+CD8+effector memory T cells (16.6% vs 25.7%), plasma cells (0.04% vs. 0.17%) were statistically higher in the patients with RA compared to HCs. While the proportion of Tph cells showed weak correlation with DAS28-ESR (r= 0.18), that was extremely higher in RA (0.08% vs. 0.25%). Interestingly, when assessing the correlations with the disease activity in seropositive and seronegative RA separately, the proportions of Tph cells (r= 0.52) and HLA-DR+Tph cells (r= 0.50) were highly reflected in seropositive RA, but not in seronegative RA. Regarding the disease activity after the MTX treatment, the change of proportion of Tph cells between week 0 and 52 significantly reflected the change of DAS28-ESR (r= 0.75, p= 0.025), but not HLA-DR+Tph cells because of the non-specific reduction by the MTX treatment. Rather, HLA-DR-Tph cells significantly reflected the change of DAS28-ESR while receiving the MTX treatment (r= 0.76, p= 0.021).

Conclusion:

Tph cells and HLA-DR+Tph cells highly reflected the disease activity of seropositive RA. However, after the treatment, the proportion of HLA-DR+Tph cells decreased independent from the disease activity, and that of HLA-DR-Tph cells more accurately reflected the change of the disease activity during the treatment.

References:

[1]Rao DA, et al. Pathologically expanded peripheral T helper cell subset drives B cells in rheumatoid arthritis. Nature. 2017;542:110-114.

Disclosure of Interests:

Hiroki Yamada: None declared, Takanori Sasaki: None declared, Katsuya Suzuki: None declared, Masaru Takeshita: None declared, Shuhei Tanemura Employee of: I am employed by Mitsubishi Tanabe Pharma Corporation, Noriyasu Seki Employee of: I am employed by Mitsubishi Tanabe Pharma Corporation, Hideto Tsujimoto Employee of: I am employed by Mitsubishi Tanabe Pharma Corporation, Tsutomu Takeuchi Grant/research support from: Eisai Co., Ltd, Astellas Pharma Inc., AbbVie GK, Asahi Kasei Pharma Corporation, Nippon Kayaku Co., Ltd, Takeda Pharmaceutical Company Ltd, UCB Pharma, Shionogi & Co., Ltd., Mitsubishi-Tanabe Pharma Corp., Daiichi Sankyo Co., Ltd., Chugai Pharmaceutical Co. Ltd., Consultant of: Chugai Pharmaceutical Co Ltd, Astellas Pharma Inc., Eli Lilly Japan KK, Speakers bureau: AbbVie GK, Eisai Co., Ltd, Mitsubishi-Tanabe Pharma Corporation, Chugai Pharmaceutical Co Ltd, Bristol-Myers Squibb Company, AYUMI Pharmaceutical Corp., Eisai Co., Ltd, Daiichi Sankyo Co., Ltd., Gilead Sciences, Inc., Novartis Pharma K.K., Pfizer Japan Inc., Sanofi K.K., Dainippon Sumitomo Co., Ltd.

Characteristics of plasma window with various channel diameters for accelerator applications

Plasma window is a feasible device as an atmosphere-vacuum interface, which can withstand energetic particle beams. It is, however, essential to enlarge the diameter to several tens of millimeters for actual beam passing in the accelerator applications. The pressure separation performance and discharge voltage V current I characteristics should be investigated in detail to design the plasma window for each purpose. Therefore, a cascade arc discharge device with a diameter of up to 20 mm was developed, and its characteristics as a function of diameter were examined. As a result, with an increase in the channel diameter, the discharge pressure that was achieved decreased, whose values were smaller compared with the values by the prediction formula, assuming the viscous gas flow with a constant plasma temperature. It showed that the bulk plasma temperature for the larger discharge channel was low because of the low-current density over the channel. Furthermore, the transition of the V-I slope was observed with an increase in the diameter.

Pathological Features of Complete Atrioventricular Block in Dogs with Lymphocytic Myocarditis

The cardiac conduction system was examined histologically in 12 canine cases of lymphocytic myocarditis with complete atrioventricular (AV) block. Histological analysis showed active myocarditis characterized by intense infiltration of mononuclear cells, primarily lymphoid, associated with degeneration and necrosis of the adjacent cardiomyocytes. Additionally, there was healing or healed myocarditis manifested by disappearance of cardiomyocytes and replacement fibrosis. This destructive inflammatory process of lymphocytic myocarditis involved the whole of the AV conduction system, resulting in loss and deletion of the conduction fibres, as well as the myocardium of all chambers. Such total or subtotal destruction of the AV conduction system caused by the inflammatory changes was thought to have set the stage for blocking AV conduction of cardiac impulses, but the aetiology of the lymphocytic myocarditis was not elucidated.

Recurrence of rectal anastomotic leakage following stoma closure: assessment of risk factors

AIM

In patients with a previous history of rectal anastomotic leakage (AL), the surgical indications and timing for closure of a diverting stoma have to be carefully judged. Even if AL has apparently healed before stoma closure, re-leakage may occur after closure. The aim of this study was to determine the incidence and risk factors for recurrent AL following stoma closure. We also examined the treatment strategies aiming to minimize the risk of recurrent AL.

METHODS

From January 2009 to December 2016, 1008 patients underwent sphincter-saving surgery [low anterior resection, all-sphincter-preserving rectal resection with hand-sewn coloanal anastomosis (CAA) and intersphincteric resection (ISR)] for primary rectal cancer with curative intent at our hospital. A total of 69 patients with AL with a Clavien-Dindo Grade III or more who subsequently underwent closure of a diverting stoma were retrospectively reviewed for this study.

RESULTS

The incidence of recurrent leakage after stoma closure in this series was 13% overall with an incidence of 25% in the CAA/ISR group and 5% in the low anterior resection group. Significant risk factors included hand-sewn anastomosis (P = 0.0257) compared to stapled anastomosis, ischaemia at the anastomotic site as the cause of initial AL (P < 0.001) and a shorter interval between confirmation of healing and stoma closure (P = 0.00952).

CONCLUSION

Ischaemia at the anastomotic site was the main risk factor for recurrent leakage, particularly after CAA/ISR. Additional treatment options before stoma closure should be considered to avoid re-leakage in such cases.

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.

Incidence of overwork-related mental disorders and suicide in Japan

Background

Mental disorders and suicide resulting from overwork or work-related stress have become major occupational health issues worldwide, particularly in Asian countries. However, no studies have reported incidence rates of mental disorders and suicide by sex, age group and industry, using a national database containing all cases involving compensation in Asian countries.

Aims

The present study examined incidence rates of occupational mental disorders and suicide by sex, age group and industry using a database containing all cases involving compensation for mental disorders and suicide in Japan over a 5-year period.

Methods

Cases involving compensation for mental disorders and suicide in Japan between January 2010 and March 2015 were analysed. Incidence rates over the 5-year study period were calculated by sex, age group and industry.

Results

In total, 1990 cases involving compensation for mental disorders and suicide (619 women and 1371 men) between January 2010 and March 2015 were analysed. The incidence rate involving compensation was higher in employees aged between 30 and 39 years. In men, incidence rates were higher in 'accommodation/eating/drinking services', 'information/communication' and 'scientific research, professional and technical services'. In these industries, incidence rates were particularly high for those aged 29 years or younger.

Conclusions

Our findings highlight the importance of promoting mental health support for younger employees and increasing awareness of their working conditions. Differences in incidence rates by sex, age and industry should be taken into consideration in the development of a national policy and industry- and age-specific preventive measures for overwork-related mental disorders and suicide.

Peripheral administration of κ-opioid receptor antagonist stimulates gonadotropin-releasing hormone pulse generator activity in ovariectomized, estrogen-treated female goats

Pulsatile gonadotropin-releasing hormone (GnRH) secretion is indispensable for reproduction in mammals. Kisspeptin neurons in the hypothalamic arcuate nucleus (ARC), referred to as KNDy neurons because of the coexpression of neurokinin B and dynorphin A, are considered as components of the GnRH pulse generator that produces rhythmic GnRH secretion. The present study aimed to investigate if peripheral administration of PF-4455242, a κ-opioid receptor (KOR, a dynorphin A receptor) antagonist, facilitates pulsatile luteinizing hormone (LH) secretion and GnRH pulse generator activity in estrogen-treated ovariectomized Shiba goats to determine the possibility of using KOR antagonists to artificially control ovarian activities. PF-4455242 was intravenously infused for 4 h (1 or 10 μmol/kg body weight/4 h) or as a single subcutaneous injection (1 or 10 μmol/kg body weight). In a separate experiment, the same KOR antagonist (10 μmol/kg body weight/4 h) was intravenously infused during the recording of multiple unit activity (MUA) in the ARC that reflects the activity of the GnRH pulse generator to test the effects of KOR antagonist administration on GnRH pulse generator activity. Intravenous infusion and single subcutaneous injection of the KOR antagonist significantly increased the frequency of LH pulses compared with controls. Intravenous infusion of KOR antagonist also significantly increased the frequency of episodic bursts in the MUA. The present study demonstrates that peripherally administered KOR antagonist stimulates pulsatile LH secretion by acting on the GnRH pulse generator, and peripheral administration of PF-4455242 can be used to facilitate pulsatile LH secretion, which in turn facilitates ovarian activities in farm animals.