A66 Tracing the evolutionary history of an emerging Salmonella 4,[5],12:i:- clone in the United States

Salmonellosis is one of the leading causes of foodborne disease worldwide, with an estimated one million cases a year in the United States. Salmonella 4,[5],12: i:-, a monophasic variant of Salmonella typhimurium, is an emerging serovar that has been associated with multiple foodborne outbreaks throughout the world, mostly attributed to pig and pig products. Recently, we have demonstrated that two distinct groups of Salmonella 4,[5],12:i:- circulate in the USA and Europe, with the majority of isolates recovered during recent years belonging to an emerging multidrug-resistant clade (Elnekave et al. 2018). We applied Bayesian phylodynamic reconstruction to uncover the evolutionary history of this clade. We used a dataset of whole-genome sequences of 1446 4,[5],12:i:- isolates from different sources (livestock, human, food products, and others) from the USA (n = 752) and Europe (n = 694), collected between 2008 and 2017 and belonging to the Multilocus Subtype 34, which was predominant in the emerging clade (Elnekave et al. 2018). A subset (n = 110) of Salmonella 4,[5],12:i: isolates was then randomly selected after stratifying by location and year of isolation in order to achieve balanced sampling. Evidence of temporal signal was confirmed by looking at root-to-tip divergences using TempEst. Evolutionary hypotheses using strict and relaxed-clock models were tested using BEAST for a variety of demographic models and assuming a general time reversible substitution model. Model selection was performed by estimating Bayes Factors using path sampling and stepping-stone sampling. The selected model was then used for applying discrete trait models comparing different scenarios of transmission between locations (i.e. bidirectional symmetric/asymmetric or unidirectional). Our preliminary phylodynamic inference results indicate that the origin of this subtype was in Europe and dates back to 1990 (HPD 95%: 1984–2001). We report an exponential growth rate of 0.362 per year, which corresponds to a doubling time of 1.43 years. Our results suggest that this subtype was introduced to the US in the year 2000 (HPD 95%: 1994–2006). Phylodynamic analysis suggests that the recent increase in isolation of Salmonella 4,[5],12:i:- from different sources in the USA may be due to the exponential expansion of an emerging clone which originated in Europe and then expanded to the USA. The emergence and expansion of this serovar is of great public health importance due to the high prevalence of multidrug resistance traits found in USA isolates from this group and especially due to the presence of plasmid-mediated resistance genes for quinolones and extended spectrum cephalosporins, key antimicrobials used for the treatment of invasive Salmonella infections.

Analysis of fatty acids in mouse tissue via in situ transmethylation with biochar

Lipid derivatization technology-mediated fatty acid profiling studies have been suggested to dissect the contents of lipids in white fat and brown fat tissue. The focus of this study is to profile fatty acid lipidomics in brown adipose tissue and white adipose tissue of mice by derivatizing their lipids into fatty acid methyl esters via in situ transmethylation using a rice husk-derived biochar as porous media. The in situ transmethylation using biochar is advantageous in biological analysis because there was no loss of samples inevitably occurring in the loss of lipid in solvent extraction and purification steps.

TLR4-dependent effects of ISAg treatment on conventional T cell polarization in vivo

We recently demonstrated that the polysaccharide component of the Korean medicinal herb Angelica gigas (immuno-stimulatory fraction of A. gigas; ISAg) induces anticancer effects in mice by activating natural killer (NK) and natural killer T (NKT) cells. However, it is unclear whether the use of ISAg in vivo can affect the differentiation of conventional T cells. Here, we investigated the effects of ISAg on the activation of conventional CD4⁺ and CD8⁺ T cells. We found that the administration of ISAg induced the polarization of CD4⁺ T cells toward the acquisition of the Th1 phenotype in vivo. Additionally, in mice treated with ISAg, CD8⁺ T cells produced more IFNγ than in control mice treated with PBS. Moreover, treatment with ISAg activated CD4⁺ and CD8⁺ T cells as well as NK and NKT cells, resulting in the secretion of Th1-type cytokines in a toll-like receptor 4 (TLR4)-dependent manner, implying that TLR4 is critical for an optimal Th1 response. Interestingly, ISAg treatment increased the number of Foxp3⁺ Treg cells, but not of Th2 cells, compared to control mice treated with PBS, indicating that ISAg possesses an immunomodulatory capacity that can control adaptive immune responses. Taken together, our results indicate that ISAg possesses a Th1-enhancing activity that could be used to treat Th2-mediated allergic immune diseases such as atopic dermatitis.

A carrier-free multiplexed gene editing system applicable for suspension cells

Genetically engineered cells via CRISPR/Cas9 system can serve as powerful sources for cancer immunotherapeutic applications. Furthermore, multiple genetic alterations are necessary to overcome tumor-induced immune-suppressive mechanisms. However, one of the major obstacles is the technical difficulty with efficient multiple gene manipulation of suspension cells due to the low transfection efficacy. Herein, we established a carrier-free multiplexed gene editing platform in a simplified method, which can enhance the function of cytotoxic CD8⁺ T cells by modulating suspension cancer cells. Our multiple Cas9 ribonucleoproteins (RNPs) enable simultaneous disruption of two programmed cell death 1 (PD-1) ligands, functioning as negative regulators in the immune system, by accessing engineered Cas9 proteins with abilities of complexation and cellular penetration. In addition, combination with electroporation enhanced multiple gene editing efficacy, compared with that by treatment of multiple Cas9 RNPs alone. This procedure resulted in high gene editing at multiple loci of suspension cells. The treatment of multiple Cas9 RNPs targeting both ligands strongly improved Th1-type cytokine production of cytotoxic CD8⁺ T cells, resulting in synergistic cytotoxic effects against cancer. Simultaneous suppression of PD-L1 and PD-L2 on cancer cells via our developed editing system allows effective anti-tumor immunity. Furthermore, the treatment of multiple Cas9 RNPs targeting PD-L1, PD-L2, and TIM-3 had approximately 70-90% deletion efficacy. Thus, our multiplexed gene editing strategy endows potential clinical utilities in cancer immunotherapy.

The effects of cortisol and adrenal androgen on bone mass in Asians with and without subclinical hypercortisolism

Analyses using the largest Korean cohort of adrenal incidentaloma (AI) revealed that subtle cortisol excess in premenopausal women and reduced dehydroepiandrosterone-sulfate (DHEA-S) in postmenopausal women and men are associated with bone mineral density (BMD) reduction in Asian patients with subclinical hypercortisolism (SH).

INTRODUCTION

Few studies evaluated bone metabolism in Asians with SH. We investigated associations of cortisol and DHEA-S, an adrenal androgen, with BMD in Asians with AI, with or without SH.

METHODS

We used cross-sectional data of a prospective multicenter study from Korea. We measured BMD, bone turnover markers, cortisol levels after 1-mg dexamethasone suppression test (1-mg DST), DHEA-S, and baseline cortisol to DHEA-S ratio (cort/DHEA-S) in 109 AI patients with SH (18 premenopausal, 38 postmenopausal women, and 53 men) and 686 with non-functional AI (NFAI; 59 premenopausal, 199 postmenopausal women, and 428 men).

RESULTS

Pre- and postmenopausal women, but not men, with SH had lower BMDs at lumbar spine (LS) than those with NFAI (P = 0.008~0.016). Premenopausal women with SH also had lower BMDs at the hip than those with NFAI (P = 0.009~0.012). After adjusting for confounders, cortisol levels after 1-mg DST demonstrated inverse associations with BMDs at all skeletal sites only in premenopausal women (β = - 0.042~- 0.033, P = 0.019~0.040). DHEA-S had positive associations with LS BMD in postmenopausal women (β = 0.096, P = 0.001) and men (β = 0.029, P = 0.038). The cort/DHEA-S had inverse associations with LS BMD in postmenopausal women (β = - 0.081, P = 0.004) and men (β = - 0.029, P = 0.011). These inverse associations of cort/DHEA-S remained significant after adjusting for cortisol levels after 1-mg DST (β = - 0.079~- 0.026, P = 0.006~0.029). In postmenopausal women, the odds ratios of lower BMD by DHEA-S and cort/DHEA-S was 0.26 (95% CI, 0.08-0.82) and 3.40 (95% CI, 1.12-10.33), respectively.

CONCLUSION

Subtle cortisol excess in premenopausal women and reduced DHEA-S in postmenopausal women and men may contribute to BMD reduction in Asians with SH.

MMP-8-Responsive Polyethylene Glycol Hydrogel for Intraoral Drug Delivery

Currently available drug delivery systems for oral diseases suffer from short retention time and poor local concentrations at the target site. A biodegradable stimulus-responsive hydrogel was synthesized in the present study to evaluate its application as an environmentally sensitive carrier for on-demand intraoral drug delivery. The hydrogel was synthesized from diacrylate-containing polyethylene glycol-based scaffolds and a cysteine-terminated peptide crosslinker (CGPQG↓IWGQC) via a Michael-type addition reaction. Because CGPQG↓IWGQC can be cleaved by matrix metalloproteinase 8 (MMP-8), minocycline hydrochloride, bovine serum albumin, or an antibacterial peptide (KSL) was incorporated into the scaffolds to evaluate the MMP-8-responsive release behavior of the on-demand drug delivery system. Hydrogel characterization and gelation kinetics were examined with gel time, Fourier-transform infrared spectroscopy, scanning electron microscopy, and measurements of rheologic parameters. Degradation behavior and MMP-8-responsive drug release were performed by high-performance liquid chromatography and protein-specific assay. Biocompatibility evaluation indicated that the hydrogels were noncytotoxic. Antibacterial testing demonstrated that the released drugs were able to maintain bioactivity. Taken together, these results suggest that the MMP-8-sensitive hydrogel is a promising candidate for on-demand intraoral localized drug delivery. Because MMP-8 is one of the most important biomarkers for periodontitis, the MMP-8-responsive hydrogel has potential to be used for in situ adaptive degradation in response to chronic periodontitis and peri-implantitis. This notion has to be tested in animal models of periodontal disease.

6-year change in resting heart rate is associated with incident type 2 diabetes mellitus

BACKGROUND AND AIMS

Elevated resting heart rate (RHR) is associated with risk of type 2 diabetes mellitus (T2DM). However, the association of change in RHR (ΔRHR) and incident T2DM is not fully elucidated. We aimed to assess the dose-response association between 6-year ΔRHR and T2DM.

METHODS AND RESULTS

A total of 12155 non-T2DM participants ≥18 years old were enrolled during 2007-2008 and followed up during 2013-2014. ΔRHR was calculated by subtracting the baseline RHR from the RHR value at 6-year follow-up. Age-, sex-, and RHR-specific relative risks (RRs) and 95% confidence intervals (CIs) for the effect of ΔRHR on incident T2DM were calculated by using modified Poisson regression models. As compared with ΔRHR of 0 beats/min, the adjusted risk of T2DM was significantly increased with RHR increment and reduced with RHR reduction. ΔRHR was positively associated with future risk of T2DM [RR per unit increase: 1.03 (1.03-1.04)]. As compared with stable change in RHR group (-5<ΔRHR<5 beats/min), for ΔRHR ≤ -10 beats/min, -10<ΔRHR ≤ -5 beats/min, 5≤ΔRHR<10 beats/min, and ΔRHR ≥10 beats/min groups, the pooled adjusted RR (95% CI) of T2DM was 0.69 (0.55-0.86), 0.90 (0.73-1.11), 1.31 (1.07-1.61), and 1.90 (1.59-2.26), respectively. This significant association still existed on subgroup analyses based on age, sex, and baseline RHR and sensitivity analyses.

CONCLUSIONS

Dynamic RHR change was significantly associated with incident T2DM. Our study suggests that RHR may be a non-invasive clinical indicator for interventions aiming to reduce incident T2DM in the general population.

Abstract P6-18-11: Long-term responders to single-agent margetuximab, an Fc-modified anti-HER2 monoclonal antibody, in metastatic HER2+ breast cancer patients with prior anti-HER2 therapy

Background

Margetuximab is an Fc-optimized anti-HER2 antibody that recognizes the same epitope as trastuzumab. Margetuximab has increased affinity for the activating CD16A Fc-receptor on NK cells and macrophages as well as decreased affinity for the inhibitory CD32B receptor compared to trastuzumab. In a Phase 1 study (NCT01148849) of 66 patients with relapsed or metastatic HER2+ cancer across multiple indications, margetuximab was well tolerated at all doses. Among 60 response-evaluable patients, confirmed partial response (PR) and stable disease (SD) were seen in 7 (12%) and 30 (50%) patients, respectively. Tumor reductions occurred in 18/23 (78%) evaluable breast cancer patients. Ex-vivo analyses of patient peripheral blood mononuclear cell samples confirmed margetuximab's ability to enhance antibody dependent cell-mediated cytotoxicity over that from trastuzumab. We report on 3 breast cancer patients with prior anti-HER2 therapy failure with durable (≥ 3.5 years) SD (1) or PR (2).

Methods

Enrolled patients had histologically/cytologically-confirmed carcinoma with documented HER2 overexpression by immunohistochemistry (2+ or 3+) and disease progression during/following last therapy. Eligibility included life expectancy ≥3 months; performance status ≤1; measurable disease by Response Criteria for Solid Tumors 1.1; adequate bone marrow, renal, hepatic function; and left ventricular ejection fraction ≥50%. Margetuximab was given by intravenous infusion at 0.1 – 6.0 mg/kg for 3 of every 4 weeks or once every 3 weeks (10 – 18 mg/kg).

Results

Three of 17 HER2 3+ metastatic breast cancer patients received long-term margetuximab. Patient 35 had 3 prior regimens (adjuvant doxorubicin+cyclophosphamide followed by docetaxol+trastuzumab; gemcitabine+vinorelbine; lapatinib+capecitabine) and received margetuximab at 10 mg/kg q3wk, 88 cycles to date, with PR achieved Cycle 1 Day 43, maintained 4.4 years. Patient 44 had 3 prior regimens for metastatic disease (docetaxel+trastuzumab+pertuzumab; doxorubicin+cyclophosphamide; lapatinib+capecitabine) and received margetuximab at 15 mg/kg q3wk, 79 cycles to date with SD for 4.3 years. Patient 50 had 4 prior regimens for recurrent/metastatic disease (tamoxifen; anastrozole; capecitabine+trastuzumab; lapatinib+capecitabine) and received margetuximab dose of 18 mg/kg q3wk with PR achieved Cycle 1 Day 43, maintained 3.5 years. Progression was noted at Cycle 57, and margetuximab continues at 63 cycles to date. No cardiac toxicities were found during long-term follow-up for these 3 patients and there were no treatment-related adverse events ≥Grade 3.

Conclusions

Margetuximab is well-tolerated without cardiac toxicities in long-term responders, with single-agent activity including durable responses in heavily pre-treated metastatic breast cancer. A Phase 3, randomized, multi-center clinical trial (SOPHIA; NCT02492711) is enrolling patients with metastatic breast cancer, comparing margetuximab plus chemotherapy to trastuzumab plus chemotherapy in patients who have received 1 to 3 lines of therapy for advanced disease.

Citation Format: Im S-A, Bang Y-J, Oh D-Y, Giaccone G, Bauer T, Nordstrom J, Li H, Moore P, Hong S, Baughman J, Rock E, Burris H. Long-term responders to single-agent margetuximab, an Fc-modified anti-HER2 monoclonal antibody, in metastatic HER2+ breast cancer patients with prior anti-HER2 therapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-11.

Clinical characteristics of diabetic ketoacidosis in users and non-users of SGLT2 inhibitors

AIM

This study investigated the clinical characteristics of diabetic ketoacidosis (DKA) and compared the DKA characteristics between patients treated with and without SGLT2 inhibitors.

METHODS

Data were collected from patients aged ≥ 18 years admitted for DKA at nine centres in Korea between September 2014 and April 2017. The electronic medical records of these subjects were retrospectively reviewed. Based on their history of medications taken before admission, subjects were classified as either users or non-users of SGLT2 inhibitors and their clinical characteristics of DKA were compared.

RESULTS

During the study, the main subtype of DKA episodes (n = 523) was identified as type 2 diabetes (51%). Average hospitalization duration was 11 days, and average intensive care unit (ICU) time was 2.5 days. The in-hospital mortality rate was 3%, but no users of SGLT2 inhibitors died during DKA treatment. In patients taking SGLT2 inhibitors (n = 15), DKA manifested at 124 days, on average, after starting the inhibitors (range: 7-380 days). Also, SGLT2 inhibitors users had significantly lower plasma glucose levels (413 mg/dL) compared with non-users (554 mg/dL), and longer ICU stays (4 vs. 2 days; P = 0.019).

CONCLUSION

In this report of recent data on the clinical features of DKA in Korea, patients using SGLT2 inhibitors needed longer treatment in ICUs compared with non-users and had lower levels of blood glucose, whereas DKA associated with SGLT2 inhibitors was rare.

Silencing of ATPase family AAA domain-containing protein 2 inhibits migration and invasion of colorectal cancer cells

Colorectal cancer is one of the most common malignant tumors with a high rate of distant metastasis, postoperative recurrence and mortality. ATPase family AAA domain-containing protein 2 (ATAD2), a member of ATPase family, is highly expressed in various cancers, including colorectal cancer. However, whether ATAD2 plays a role in the migration and invasion of colorectal cancer cells remains unknown. In this study, we established ATAD2 knockdown in colorectal cancer cell lines by RNA interference and found that silencing of ATAD2 inhibited the migration and invasion ability of Caco-2 and SW-480 cells. Moreover, ATAD2 silencing suppressed epithelial-mesenchymal transition (EMT), and reduced the expression and enzymatic activity of matrix metalloproteinases (MMPs) in Caco-2 and SW-480 cells. In summary, our results suggest that silencing of ATAD2 inhibits migration and invasion of colorectal cancer cells by suppressing EMT and decreasing the activity of MMPs. Hence, ATAD2 could be considered as a novel molecular marker of metastatic colorectal cancer, and it may provide new insights for clinical diagnosis and treatment of colorectal cancer.

Long-term immunogenicity and immune persistence of live attenuated and inactivated hepatitis a vaccines: a report on additional observations from a phase IV study

Both live attenuated (HA-L) and inactivated (HA-I) hepatitis A vaccine were licensed for routine use in China. Although phase 1, 2 and 3 clinical studies of both vaccines have been completed, further systematic evaluation of their immunogenicity and immunological persistence under phase 4 clinical studies in a wide range of conditions and involving large populations is necessary. A phase IV clinical trial (NCT02601040) was performed in 9000 participants over 18 months of age. Geometric mean concentrations (GMCs) and seroconversion rates (SRs) were compared at five time points during 3 years for 1800 individuals among them. The SRs of HA-L and HA-I were 98.08% (95% CI 95.59%-99.38%) and 99.64% (95% CI 98.93%-100.00%) respectively 28 days after administration of the first dose, and remained at 97.07% (95% CI 94.31%-98.73%) or above and 96.73% (95% CI 94.07%-98.42%) or above respectively during the following 3 years. The GMCs for both the HA-L and HA-I groups showed that both vaccines elicited high anti-HAV titres, considerably more than the threshold of protection needed against HAV infection in humans, and these titres were sustained. Hence, both HA-I and HA-L vaccines could provide an excellent long-term protective effect, and supported the routine use of both vaccines.

A J-shaped relation of BMI and stroke: Systematic review and dose-response meta-analysis of 4.43 million participants

BACKGROUND AND AIM

Many studies have shown increased risk of stroke with greater adiposity as measured by body mass index (BMI), but questions remain about the shape of the dose-response relation. We conducted a systematic review and meta-analysis of prospective studies to clarify the strength and shape of the dose-response relation between BMI and risk of stroke.

METHODS AND RESULTS

PubMed and Embase databases were searched for articles published up to May 11, 2018. Random-effects generalized least-squares regression models were used to estimate study-specific dose-response association, and restricted cubic splines were used to model the association. We included reports of 44 prospective cohort studies describing 102 466 incident cases among 4 432 475 participants. With a 5-unit increment in BMI, the summary relative risk for stroke incidence was 1.10 (95% confidence interval, 1.06 to 1.13; I² = 88.0%). The dose-response relation was J-shaped (P_{non-linearity} <0.001). The risk was not increased at the low BMI range (<24 kg/m²), but was increased within the high BMI range (>25 kg/m²).

CONCLUSION

Both overweight and obesity increase the risk of stroke with a J-shaped dose-response relation, and the nadir of the curve was observed at BMI 23-24 kg/m².

iNKT Cells Suppress Pathogenic NK1.1+CD8+ T Cells in DSS-Induced Colitis

T cells producing IFNγ play a pathogenic role in the development of inflammatory bowel disease (IBD). To investigate the functions of CD1d-dependent invariant natural killer T (iNKT) cells in experimental colitis induced in Yeti mice with dysregulated expression of IFNγ, we generated iNKT cell-deficient Yeti/CD1d KO mice and compared colitis among WT, CD1d KO, Yeti, and Yeti/CD1d KO mice following DSS treatment. We found that deficiency of iNKT cells exacerbated colitis and disease pathogenesis was mainly mediated by NK1.1⁺CD8⁺ T cells. Furthermore, the protective effects of iNKT cells correlated with up-regulation of regulatory T cells. Taken together, our results have demonstrated that CD1d-dependent iNKT cells and CD1d-independent NK1.1⁺CD8⁺ T cells reciprocally regulate the development of intestinal inflammatory responses mediated by IFNγ-dysregulation. These findings also identify NK1.1⁺CD8⁺ T cells as novel target cells for the development of therapeutics for human IBD.