Temporal Changes in Innate and Adaptive Immunity During Sepsis as Determined by ELISpot

Background

The inability to evaluate host immunity in a rapid quantitative manner in patients with sepsis has severely hampered development of novel immune therapies. The ELISpot assay is a functional bioassay that measures the number of cytokine-secreting cells and the relative amount of cytokine produced at the single-cell level. A key advantage of ELISpot is its excellent dynamic range enabling a more precise quantifiable assessment of host immunity. Herein, we tested the hypothesis on whether the ELISpot assay can detect dynamic changes in both innate and adaptive immunity as they often occur during sepsis. We also tested whether ELISpot could detect the effect of immune drug therapies to modulate innate and adaptive immunity.

Methods

Mice were made septic using sublethal cecal ligation and puncture (CLP). Blood and spleens were harvested serially and ex vivo IFN-γ and TNF-α production were compared by ELISpot and ELISA. The capability of ELISpot to detect changes in innate and adaptive immunity due to in vivo immune therapy with dexamethasone, IL-7, and arginine was also evaluated.

Results

ELISpot confirmed a decreased innate and adaptive immunity responsiveness during sepsis progression. More importantly, ELISpot was also able to detect changes in adaptive and innate immunity in response to immune-modulatory reagents, for example dexamethasone, arginine, and IL-7 in a readily quantifiable manner, as predicted by the reagents known mechanisms of action. ELISpot and ELISA results tended to parallel one another although some differences were noted.

Conclusion

ELISpot offers a unique capability to assess the functional status of both adaptive and innate immunity over time. The results presented herein demonstrate that ELISpot can also be used to detect and follow the in vivo effects of drugs to ameliorate sepsis-induced immune dysfunction. This capability would be a major advance in guiding new immune therapies in sepsis.

Impacts on the short-term outcome of patients with Tako-Tsubo syndrome

Background

Tako-Tsubo syndrome (TTS) is a form of acute heart failure which mostly affects postmenopausal women, often following an emotional or physical trigger factor. There are many hypotheses for the development of TTS but the complete pathophysiology still remains unclear. Although most patients recover after a few days, some have to be treated at the intensive care unit (ICU) and may even die from the condition.

Purpose

The aim of this study was to find out if pre-existing diseases, cardiovascular risk factors (CVRF), comorbidities and trigger factors have any impact on the short-term outcome of TTS patients.

Methods

Data of all patients who presented to our centre with TTS from 2009–2017 were gathered retrospectively. Baseline characteristics, including somatic and psychiatric pre-existing diseases, CVRF (smoking, hypertension, diabetes, dyslipidaemia) as well as physical and emotional trigger factors were collected. Somatic diseases were additionally categorised into cardiac, autoimmune, malignant and other diseases. Admission to intensive care unit post TTS and/or in-hospital death were defined as poor short-term outcome. Outcome predictors were analysed with binary logistic regression model using the combined variable admission to an ICU and/or death.

Results

Out of 102 patients, 84 (82.4%) were females and 18 (17.6%) males with a median age of 65±15 years. 30 (29.4%) patients had an emotional and 23 (22.5%) a physical trigger factor. 27 (26.5%) had a psychiatric and 88 (86.3%) a somatic pre-existing disease. 33 (32.4%) patients were smokers, 58 (56.3%) had hypertension and 18 (17.5%) were diabetics. 19 patients (18.6%) had to be admitted to ICU and 8 patients (7.8%) died.

No pre-existing diseases, baseline characteristics, CVRF or comorbidities behaved as significant independent predictor for bad outcome in TTS patients. Physical trigger was the only significant predictor for ICU admission and/or death (p=0.012).

Conclusion

Our study showed that patients with physical trigger factors have a higher risk of ICU admission and/or death than patients with emotional or no stressful trigger factors before TTS and should therefore be monitored closely. Interestingly, contrary to many other acute cardiac diseases, pre-existing diseases, cardiovascular risk factors and comorbidities do not seem to have any impact on the short-term outcome of patients with TTS.

Funding Acknowledgement

Type of funding sources: None.

Elevated high-sensitivity C-reactive protein and the risk for cardiovascular events in chronic cardiac disease

Background

High sensitivity C-reactive protein (hs-CRP) is a biomarker used for risk prediction for cardiovascular disease by assessing low concentration of inflammation. This study aims to assess the event-free time for the composite outcome between patients of different hs-CRP risk groups and the possible predictive value of hs-CRP for event occurrence in patients with chronic cardiac disease.

Methods

Data from 607 consecutive patients referred for cardiovascular risk assessment with hs-CRP from November 2017 to October 2018 were reviewed retrospectively. Routine peripheral venous blood samples were taken on the day of study inclusion and sent to the local laboratory, where laboratory parameters were analyzed and processed in accordance with local laboratory standards. 570 patients who had hs-CRP measurement by immunoturbidimetric assay were included in the analysis and classified into three (low-, medium- and high-risk) groups (hs-CRP cut-off: <1, 1–3, >3 mg/L). Association between hs-CRP and occurrence of the composite outcome (acute myocardial infarction, stroke, coronary intervention (percutaneous coronary intervention or bypass surgery) or death) was determined with Cox regression analysis and visualized with Kaplan Meier curves.

Results

In total, 570 patients from our cardiology outpatient clinic were included in this study. Cohorts were formed according to hs-CRP risk groups, 209 (36.7%), 226 (39.6%) and 135 (23.7%) patients were classified as low-, medium- and high-risk, respectively. The composite endpoint occurred in 93 (19.1%) of the 486 patients with available follow-up. Events occurred in 29 (16.3%), 30 (15.7%), 34 (29.1%) patients of the low-, medium- and high-risk group, respectively (p=0.016). There was a significant difference in the event-free survival time patients of the low- and medium-risk groups compared with patients in the high-risk group (p=0.015). The difference between groups is shown by the Kaplan-Meier plot (log rank test, p=0.01) (Figure 1). Univariate Cox proportional-hazard analysis identified age, hs-CRP risk group, hypertension, diabetes, hyperlipidemia, coronary artery disease, peripheral artery disease, cerebrovascular disease log(NT-proBNP) and creatinine as significant predictors for the primary study outcome. In multivariable analysis coronary artery disease and age were found to be highly significant predictors for the occurrence of an composite event during follow-up, while patients categorized in the low- and medium-risk groups appeared to predict a lower likelihood for events (Table 1).

Conclusions

Cardiovascular events were more likely to occur in patients who were older, with hs-CRP >3 mg/L and a history of coronary artery disease. However, assessment of inflammation markers alone may play a secondary role compared to other established cardiovascular risk factors, elevated CRP appears helpful to detect higher risk and in prediction of further cardiovascular events and mortality.

Funding Acknowledgement

Type of funding sources: None.

Temporal evolution of the key neurohumoral regulator renin in chronic stable HFrEF

Background

Renin is the enzyme catalyzing the rate-limiting step of the Renin-Angiotensin-System (RAS) generating Angiotensin II (AngII). RAS inhibitors are a main pillar of current heart failure with reduced ejection fraction (HFrEF). Although used since over 30 years in clinical routine, the studied effects of RAS-inhibitors on renin level changes during the course of HFrEF and its impact on patient outcomes, especially under current guideline directed medical therapy (GDMT), are lacking.

Methods

Consecutive patients with stable chronic HFrEF and GDMT were enrolled prospectively from the our outpatient unit of heart failure between 06/2013 and 08/2021. Active plasma renin concentration (ARC) was documented for all patients consecutively at first measurement, i.e. baseline (BL), and at follow-up (FUP) visits at 12, 24, 36, 48 and 60 months, respectively. BL renin was correlated with N-terminal pro B-type natriuretic peptide (NT-proBNP) and compared between NYHA class, HF medication use and renin levels between baseline and FUP timepoints. To assess the effect of changes in renin levels, patients were categorized into three groups based on the change of renin from baseline within the first year of observation: decrease = change >−50%, undulating=change between −50 to 50%, increase=change>50% and survival curves were displayed as Kaplan-Meier plots and compared for different ARC categories by the log-rank test.

Results

A total of 491 patients were included in the study. BL characteristics are shown in Table1. Renin levels showed no relationship with HF severity reflected by a lack of correlation with NT-proBNP [rs=−0.05, p=0.273] and comparable levels between NYHA groups [p=0.753] (Figure 1A). Renin levels were further comparable for different RAS inhibitors and patients with and without beta blockers, however higher in patients with mineralocorticoid receptor antagonists (MRA) [189 μIE/ml vs. 59 μIE/ml, p=0.0001] and SGLT2-inhibitors [280 μIE/ml vs. 100 μIE/ml, p=0.004] (Figure 1B). Renin levels at different yearly FUP timepoints are displayed in Figure 1C. There was no significant difference in renin levels between BL and 1-year FUP, while renin concentration was increased at 2-year FUP [126 μIE/ml vs. 243 μIE/ml, p=0.002]. Baseline renin levels were not associated with survival [crude HR for an increase of 100μiE/ml 1.014 (95% CI: 0.997–1.032), p=0.102]. Within one year following BL, renin decreased in 77 (27.6%), was undulating in 74 (26.5%) and increased in 128 (45.9%) patients. Kaplan-Meier suggests worse survival for patients with increasing renin though the difference was statistically not significant [p=0.2573] (Figure 1D).

Conclusion

Renin was elevated in patients with MRA and/or SGLT2-inhibitors. Renin tends to increase over time in stable HFrEF. Although RAS is the main target of HFrEF therapy, surprisingly there seems to be no strong association between RAS activation and thereby potential effectivity of achieved RAS-blockade and outcome.

Funding Acknowledgement

Type of funding sources: None.

Agreement between high-sensitivity C-reactive protein and C-reactive protein assays

Background

High sensitivity C-reactive protein (hs-CRP) is a biomarker used for risk prediction for cardiovascular disease (CVD) by assessing low concentrations of inflammatory markers. Measurements of regular CRP assays have become very sensitive too with a detection limit of 0.03mg/dL, while also being more available and cheaper. The aim of this study is to compare the association between CRP and hs-CRP.

Methods

This study compared CRP and hs-CRP serum concentrations and data acquired by medical chart review of 590 patients from 11/2017 to 10/2018 of our cardiology outpatient clinic who were divided into hs-CRP and CRP risk groups for CVD events: low<0.1 mg/dL, average 0.1–0.3mg/dL, high>0.3mg/dL. The agreement of classification in hs-CRP and CRP risk groups was assessed by kappa statistic, with Kappa coefficient of <0.20, 0.21–0.40, 0.41–0.60, 0.61–0.80, 0.81–0.99 interpreted as slight, fair, moderate, substantial and almost perfect agreement, respectively. Bland-Altman (BA) analysis was used to assess agreement between hs-CRP and CRP by plotting the mean of the two measurements on the x-axis against the mean difference of CRP - hs-CRP on the y-axis.

Results

Out of all 590 patients, 37.7% were in low risk, 33.9% in average risk and 28.5% in high risk hs-CRP group. Some group changes occurred after reclassification of the patients according to CRP measurements. Eight percent of patients reclassified into a higher risk group, 0.7% into a lower risk group, while 91.4% remained in the same risk group as determined by hs-CRP (kappa: 0.87; p<0.001) (Tab. 1). Important to note, there was a 100% agreement between the high-risk CRP and hs-CRP group patient classification. BA-plot displayed a fixed bias with an average difference between the two laboratory tests for CRP and hs-CRP of 0.02 mg/dL±0.09SD with only sporadic outliers (Fig. 1). The upper limit of agreement was 0.12 and lower limit of agreement was −0.07. In the lower range of CRP values, measurements were tightly clustered around the average difference. Greater variability could be observed at higher serum level of the inflammatory biomarker in the BA-plot with a bias to higher CRP concentrations than hs-CRP concentrations at values greater than 0.5mg/dL. This proportional bias, which was further demonstrated by linear regression analysis, does not affect the risk predicting qualities of hs-CRP or CRP for CVD because the cut-off values for risk groups (0.1mg/dL for low risk, 0.3mg/dL for high risk) are all below this threshold.

Conclusion

A close agreement between measurements of hs-CRP and CRP assays was identified, therefore regular CRP assays could replace hs-CRP for cardiac risk assessment. Benefits for clinical implementation are: First, CRP assessment is routinely available in most laboratories compared to hs-CRP. Second, CRP is less costly than hs-CRP, since no further laboratory acquisitions are necessary, which is especially relevant in regions where cost efficiency is of importance.

Funding Acknowledgement

Type of funding sources: None. Table 1. Kappa statisticFigure 1. Bland-Altman plot

Impact of overweight or obesity trajectory on health expenditure in Korea

BACKGROUND

This study aimed to identify the effect of the overweight or obesity (OWOB) trajectory on current health care expenditure in South Korea.

METHODS

Ten years of publicly released data (2002-12) were obtained in 2016 from a retrospective cohort of National Health Insurance System claims. This study included 51,844 adults (aged 30-59 years in 2002) and 21,196 elderly adults (aged ≥ 60 years in 2002).

RESULTS

Compared with adults who maintained normal weight (NW), higher yearly total health expenditures were estimated for adults who lost weight over the 10-year period: by 11.5% (95% confidence interval (CI): 0.18-22.96%) when changing from NW to underweight (UW) and 6.2% (95% CI: 0.47-12.01%) from OWOB to UW/NW. Elderly adults had higher health expenditures when they lost weight by 14.0% (95% CI: 0.37-27.70%) from NW to UW and 6.8% (95% CI: 0.13-13.51%) from OWOB to UW/NW compared with when they maintained NW.

CONCLUSIONS

These findings indicate the importance of early intervention to control OWOB, particularly because people in late adulthood have greater health care needs for reasons other than OWOB.

The incidence and seasonal variation of necrotizing fasciitis in Korea: a nationwide cross-sectional study

INTRODUCTION

Necrotizing fasciitis (NF) is a rare but fatal disease, and there is no known annual incidence of NF in Korea. The aim of this study was to investigate the incidence and seasonal variation of NF in Korea.

METHODS

We analysed claims from the nationwide Korean Health Insurance Review and Assessment Service database. Patients who were hospitalized with an NF diagnosis code and received surgical intervention were classified as NF cases. Poisson regression models were used to assess the relationships of incidence rates with year, age and sex. A multivariate Poisson regression model was used to investigate variations in monthly NF incidence trends.

RESULTS

From 2012 to 2017, the overall average annual NF incidence rate was found to be 0.86 per 100 000 population. NF incidence increased with age and was 2.5 times higher among males across all age groups. Two-thirds of cases occurred among patients with diabetes. The peak NF incidence occurred during the summer. Multivariate Poisson regression modelling using national meteorological variables suggested that mean temperatures and number of NF cases in the previous month were associated with the number of NF cases in the current month.

DISCUSSION

Clinicians should consider NF when encountering an elderly man with diabetes during the summer.

P869 Effect of transcatheter MitraClip implantation on exercise performance evaluated by CPET

Methods

Total body bone scintigraphy, 714 MBq 99m-Tc DPD, was performed to confirm the diagnosis of cardiac transthyretin (ATTR) amyloidosis. The extent of mitral regurgitation was assessed using TTE and TEE before and after MC implantation. Coronary angiography and right heart catheterization were performed prior to MC implantation. CPET by a cycle ergometer was used to measure the dynamic response of the heart before and after the procedure. A ramp protocol, adapted to reach maximal capacity after 8-10 min was chosen for the test. The parameter of main interest was maximal oxygen uptake (VO2 max, ml/min), the major factor known to limit exercise capacity.

Results

Bone scan showed tracer accumulation in myocardial tissue, genetic testing was negative which confirmed wild type cardiac transthyretin (ATTR) amyloidosis. Significant coronary artery disease was excluded by coronary angiography. Right heart catheterization disclosed post capillary pulmonary hypertension: mean pulmonary artery pressure of 42 mmHg and mean pulmonary capillary wedge pressure of 25 mmHg and end-diastolic pressure of left ventricle of 118 mmHg. A high grade left ventricular concentric hypertrophy (IVS = 26mm) with slightly reduced left systolic function, a severe MR (EROA = 35 mm2) and enlargement of left and right atria (LA = 68mm, RA = 68mm) were demonstrated by TTE. In TEE left atrium including left atrial appendage were free from thrombi; high grade left ventricular hypertrophy, restriction of posterior leaflet and severe MR with eccentric jet with dilated annulus were demonstrated. CPET before MC implantation: VO2 max 1299 ml/min (83% of predicted peak oxygen uptake value). MC implantation was performed with no post-procedural complications. Follow-up CPET showed higher VO2 max 1373 ml/min compared to the data before MC implantation (88% predicted peak oxygen uptake value).

Conclusions

TTE and TEE are the most common and accurate imaging modalities to evaluate MR regarding MitraClip evaluation. After the MC procedure the dynamic response of the heart can be observed by CPET with VO2 as a surrogate marker for heart function.

Abstract P869 Figure. a.b. TEE prior to MC, c.d. TEE after MC

P974 Sacubitril/valsartan is well tolerated in patients with heart failure and a history of cancer

Introduction

Sacubitril/valsartan has been shown to significantly reduce cardiovascular mortality and hospitalisations due to heart failure in patients with reduced ejection fraction when compared to enalapril. Until now, sacubitril/valsartan has not been evaluated in patients with a history of cancer, as these patients were excluded from the pivotal trial, PARADIGM-HF. The aim of the current study was to assess tolerability of sacubitril/valsartan in patients with a history of cancer.

Methods

We retrospectively enrolled all patients at our heart failure out-patient unit who fulfilled the indication criteria to receive sacubitril/valsartan and had a history of cancer. Fifteen patients receiving sacubitril/valsartan had a diagnosis of histologically confirmed cancer: 26.7% breast cancer (n = 4), 13.3% osteosarcoma (n = 2), 13.3% colorectal cancer (n = 2), 13.3% renal cell carcinoma (n = 2), 6.7% non-Hodgkin lymphoma (n = 1), 6.7% lung cancer (n = 1), 6.7% prostate cancer (n = 1), 6.7% bladder carcinoma and 6.7% myeoloproliferative syndrome (n = 1). Surgery due to cancer was performed in 80% of patients (n = 12), 26.7% previously received chemotherapy (n = 6) and 40% radiation therapy (n = 4).

Results

Sacubitril/valsartan was withdrawn in 2 patients (13.3%) because of dizziness and pruritus respectively. After a mean follow-up of 13 ±8 months, NYHA functional class improved significantly (mean -0.5, p = 0.001), ejection fraction as assassed by echocardiography increased (mean +6.8%, p = 0.018) and NT-proBNP was significantly decreased (mean -1552pg/ml, p = 0.026). There was no significant change in creatinine levels (+0.046 mg/dl, p = 0.564 ).

Conclusions

In this pilot study we were able to show that sacubitril/valsartan is generally well tolerated in patients with a history of cancer. Patients with cardiotoxicity induced heart failure can be treated and uptitrated with sacubitril/valsartan to usual dosages similarly as in other causes of heart failure. Larger studies are needed to confirm these findings in cancer patients with cardiotoxicity.

Abstract P6-02-01: Not presented

This abstract was not presented at the conference.

Citation Format: Luo J, Chen Q, Tang L, Yang L, Han E, Chen Y, Yuan L. Not presented [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 P6-02-01.

Effects of fumonisin B1 and mycotoxin binders on growth performance, tibia characteristics, gut physiology, and stress indicators in broiler chickens raised in different stocking densities

The present study was carried out to investigate the effects of stocking density, fumonisin B1 (FB), and mycotoxin binder (TB) on growth performance, bone quality, physiological stress indicators, and gut health in broiler chickens. Day-old Ross 308 male broiler chicks (n = 1,440/experiment) were randomly allocated to 72 floor pens in a 3 × 2 × 2 factorial arrangement, using 3 stocking densities (12.5 birds/m2 [HSD], 10 birds/m2 [MSD], or 7.5 birds/m2 [LSD]), 2 levels of purified FB (0 or 10 ppm), and 2 levels of TB (0 or 0.2%). Each treatment had 6 replicates (n = 6/treatment) and experiments lasted 34 days. All data were analyzed using 3-way ANOVA with stocking density level, FB, and TB as main factors. Body weight gain and feed intake were lower (P < 0.05) in broilers kept at HSD and MSD compared to LSD-housed counterparts. Birds fed an FB-contaminated diet exhibited a higher feed-to-gain ratio compared with those fed an FB-free diet (P < 0.05). None of the treatments affected intestinal morphology or ileal secretory immunoglobulin A levels. Stocking density affected tibia breaking strength (P < 0.05), which was lower in chickens housed at HSD compared with LSD-housed chickens. The heterophil/lymphocyte ratio (H/L ratio) was elevated (P < 0.05) in HSD and MSD groups compared with the LSD group. Serum nitric oxide (NO) levels were elevated (P < 0.05) in chickens fed the FB-contaminated diet compared with the control diet-fed counterparts. Significant interaction (P < 0.05) between FB and TB on serum NO levels was noted. In summary, increasing stocking density lowered growth performance and bone quality, but increased the H/L ratio. Dietary TB did not affect FB-induced increases in the feed-to-gain ratio. No interaction was observed between stocking density and FB for the measured variables.

Sarcopenia is associated with the risk of significant liver fibrosis in metabolically unhealthy subjects with chronic hepatitis B

BACKGROUND

Sarcopenia is significantly associated with the degree of liver fibrosis. This study investigated the influence of sarcopenia on liver fibrosis in individuals with chronic hepatitis B.

METHODS

Data from the Korean National Health and Nutrition Examination Surveys 2008-2011 were analysed. The sarcopenia index (total appendicular skeletal muscle mass [kg]/body mass index [kg/m² ]) was calculated using dual-energy X-ray absorptiometry. Sarcopenia was defined as the lowest quintile sarcopenia index value (cut-offs: 0.89 for men and 0.58 for women). The fibrotic burden was assessed using the nonalcoholic fatty liver disease fibrosis score and fibrosis-4 index. Significant fibrosis was defined as the highest nonalcoholic fatty liver disease fibrosis score quartile and a fibrosis-4 index ≥2.67.

RESULTS

Among the 506 respondents with chronic hepatitis B (258 men and 248 women), the nonalcoholic fatty liver disease fibrosis score and fibrosis-4 index identified sarcopenia and significant fibrosis in 126 (24.9%) and 217 (42.9%), respectively. Sarcopenia was significantly associated with significant fibrosis, regardless of the fibrosis prediction model used (all P < 0.05). When the study population was stratified according to metabolic factors, sarcopenia was specifically associated with an increased risk of significant fibrosis among subgroups with obesity, insulin resistance, metabolic syndrome and liver steatosis (odds ratio 2.37-3.57; all P < 0.05). An independent association between sarcopenia and significant fibrosis was identified after adjusting for other confounders (odds ratio 2.67-3.62 by the nonalcoholic fatty liver disease fibrosis score and 2.04-2.62 by the fibrosis-4 index; all P < 0.05).

CONCLUSIONS

Sarcopenia is associated with significant fibrosis in subjects with chronic hepatitis B, specifically those with obesity, insulin resistance, metabolic syndrome and liver steatosis.

Low-income African-American adults share weight status, food-related psychosocial factors and behaviours with their children

Objective

This study aims to examine the extent to which low‐income African‐American children's weight status, psychosocial characteristics and food‐related behaviours are associated with that of their adult caregivers.

Methods

Cross‐sectional data from baseline evaluation of B'More Healthy Communities for Kids obesity prevention trial were used. Outcomes of interest were children's overweight and/or obesity status, food‐related self‐efficacy, knowledge, intentions and healthier/less healthy food acquisition scores. The primary exposures were adult caregiver's overweight and/or obesity status, their psychosocial factors and food acquisition scores. Multiple logistic regression analyses were used to assess associations.

Results

Children had higher odds of overweight or obesity if they had an overweight/obese caregiver (odds ratio [OR] 4.04, 95% confidence interval [95%CI] 1.59–10.28) or an obese caregiver (OR 2.50, 95%CI 1.39–4.51). Having a caregiver in the highest quartile of self‐efficacy, food intentions and healthy food acquisition patterns was associated with higher odds of their child also having a higher score on these factors (self‐efficacy: OR 3.77 [95%CI 1.76–8.04]; food intentions: OR 1.13 [95%CI 1.01–1.27]; and healthy food acquisition: OR 2.19 [95%CI 1.05–4.54]).

Conclusions

Child and adult caregiver weight status and psychosocial characteristics were positively associated in this low‐income, urban population. These findings may help inform obesity treatment or prevention programmes and interventions aimed at parents and families.

POST-HARVEST EMBRYO DEVELOPMENT IN GINSENG SEEDS INCREASES DESICCATION SENSITIVITY AND NARROWS THE HYDRATION WINDOW FOR CRYOPRESERVATION

BACKGROUND

Despite its self-pollinating characteristics, Korean ginseng germplasm is mainly maintained in clonal gene banks as there is no defined approach to the long-term conservation of its seed, including the most appropriate stage of embryo development for storage.

OBJECTIVE

The aim of this study was to reveal the effect of embryo development on desiccation tolerance and cryopreservation success in ginseng seeds.

MATERIALS AND METHODS

Seeds of Korean ginseng (Panax ginseng C.A. Meyer) at three post-harvest stages (immediately after harvesting and following treatments to enable internal growth of the embryo) were desiccated and cryopreserved.

RESULTS

The hydration window for the >80% dehiscence and germination of cryopreserved ginseng seeds varied with embryo developmental stage: 3-9% moisture content (MC) for both unpulped and undehisced seeds when the embryo was 0.1 the length of the endosperm, 7-10% MC for dehisced seeds (0.5 embryo:endosperm) and 9-11% MC for seeds with fully developed embryos (0.9 embryo:endosperm). Whilst dried (4-8% moisture content) and undehisced seeds within fruits (unpulped seeds) lost more than half their viability during 1 year's storage at room temperature, cryopreservation enabled germination levels of c. 90%. Overall, 432 accessions of Korean ginseng landraces have been cryopreserved using undehisced seeds with or without fruits.

CONCLUSION

Post-harvest treatment of Korean ginseng seeds to enable embryo development decreases tolerance of very low MCs, and thus narrows the hydration window for cryopreservation. Fresh-harvested and unpulped seeds that have been dried to c. 5% MC are recommended for long-term cryogenic storage.

Abstract P3-03-08: A comparison of PI3K inhibition by eribulin, other microtubule targeting agents and a DNA-damaging chemotherapeutic in triple negative and HER2 expressing breast cancer cell lines

Background. Eribulin is a microtubule-targeting agent with significant benefits in treating refractory metastatic breast cancer. Tumors from patients with Triple negative breast cancer (TNBC) have high levels of Akt expression and consistently show activation of the PI3K-mTOR pathway. Our objective was to compare Eribulin's ability to inhibit PI3K pathway activity and cell growth with two other microtubule targeting agents, Paclitaxel and Vinblastine, as well as a conventional DNA damaging chemotherapeutic Cisplatin.

Methods. MDA468 and BT549 TNBC cell lines and SKBR3 HER2 overexpressing breast cancer cell lines were used for this study. Western blot analysis was used to evaluate the expression of phosphorylated Akt-Ser473 (pAkt) and S6K1 (pS6K1) at different time points from 2 to 24 hours of treatment with Eribulin, Paclitaxel, Vinblastine, or Cisplatin. MTT assays were used to assess growth inhibition after 72 hours of treatment.

Results. Western blot analysis for MDA468 cells treated with Eribulin in varying concentrations confirm partial inhibition of pAkt expression as early as 4 hours at 100 pM concentration. Complete inhibition is reached at 50 nM. Partial inhibition of pS6K1 can be seen as early as 4 hours at 500 nM. Western analysis for MDA468 cells treated with Vinblastine in varying concentrations confirms inhibition of pAkt and pS6K1 beginning at 50 nM at 24 hours. Western analysis for MDA468 cells treated with Paclitaxel in varying concentrations showed increases in pAkt expression in a dose responsive fashion with significant increase in pAkt beginning at 5 nM concentration as well as increase in pS6K1 at 24 hours. Cisplatin markedly increases pAkt at 24 hours in a dose responsive fashion and decreases pS6K1 at 500 nM to 1000 nM concentration range in BT549. The IC50's for Eribulin ranged from 0.06 nM to 0.3 nM at 72 hours by MTT assay. The IC50's for Vinblastine ranged from 0.5 nM to 0.9 nM. Paclitaxel has reported IC50's in the 2 nM to 75 nM range in these cell lines, and Cisplatin has IC50's ranging from to ∼500 nM to ∼2000 nM at 72 hours in these cell lines.

Conclusion. Our study shows that for microtubule targeting agents such as Eribulin and Vinblastine that block polymerization of tubulin into microtubules, both pAkt and pS6K1 expression is suppressed. Growth inhibition is also confirmed, and is seen at doses when pAkt and pS6K1 are not suppressed. Eribulin inhibits pAkt and pS6K1 at lower concentrations than Vinblastine. With Paclitaxel, a microtubule-targeting agent that enhances polymerization of tubulin to microtubules, and Cisplatin, a conventional DNA damaging chemotherapeutic we observe an increase in pAkt expression, with variable effects on pS6K1. Enhancement of Akt activity is a likely survival response by cancer cells to chemotherapy, yet in the case of microtubule polymerization blockade as seen with Eribulin and Vinblastine, Akt activity is suppressed, along with downstream mTOR activity. The potential role of microtubule polymerization blockade in inhibition of the PI3K pathway needs further study. It may be a factor in the novel finding of pAkt and pS6K1 inhibition by Eribulin.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-03-08.

Abstract P3-03-07: Combination of eribulin and PI3K inhibitors in triple negative and HER2 expressing breast cancer cell lines results in synergistic growth inhibition and enhanced inhibition of the PI3K pathway

Background. Patients with triple negative breast cancer (TNBC) have high levels of pAkt expression and activation of the PI3K-mTOR pathway. Eribulin is a microtubule-targeting agent with benefits in treating taxane and anthracycline refractory breast cancer. Our objective was to evaluate its efficacy in inhibiting PI3K pathway activity and cell growth both alone and in combination with PI3K/MTOR inhibitors BEZ 235 and BKM 120.

Methods. TNBC cell lines MDA468, BT549, HS587T, MDA231, and HER2 expressing breast cancer cell line SKBR3 were used for this study. Both MDA468 and BT549 have PI3K- related mutations. The tetrazolium salt, 3-4,5 dimethylthiazol-2,5 diphenyl tetrazolium bromide (MTT) assays were used to assess growth inhibition after 72 hour treatment with eribulin, BEZ 235 and BKM 120 both alone and in combination. Combination indices (CI) generated by Chou-Talalay plots were used to quantify synergy. Western blots were used to evaluate the expression of phosphorylated Akt (pAkt), S6K1 (pS6K1) and S6 (pS6) from 30 min to 24 hours of treatment at different doses.

Results. Eribulin has IC50 ranging from 60 pM to 300 pM, BEZ 235 has IC50 ranging from 50 nM to 80 nM, and BKM has IC50 ranging from 500 nM or higher. Standard dilutions of eribulin in combination with BEZ 235 resulted in synergistic growth inhibition (CI&lt;1) in both MDA468 and BT549 cells at all doses tested, but required higher concentrations (500 to 2000 nM) for BKM 120. Western blot analysis for all cell lines treated with eribulin showed pAkt inhibition by eribulin alone with doses as low as 1 nM and as early as 4 hours. PI3K inhibitor alone confirmed inhibition of pAkt, pS6K1 and pS6 at early time points with feedback increase in pAkt at 24h. While both BEZ 235 and BKM 120 treatment increased pAkt in a dose dependent fashion at 24 hours, combination treatment with eribulin showed a dose dependent decrease in pAkt.

Conclusion. Our study shows significant synergistic growth inhibition with the combination of eribulin and PI3K inhibitors. This may be related to inhibition by eribulin of the feedback increase in pAkt seen with PI3K inhibitors alone at later time points. These findings point to a potential role for combination therapy of both eribulin and PI3K inhibitors in treating refractory metastatic disease.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-03-07.

Magneto-elastic buckling of an Euler beam

We consider nonlinear elastic deformations of a magneto-elastic beam, using a combined experimental and theoretical approach. In the experiments, a beam had one end clamped with a magnet attached at its free end. When it was placed in an external magnetic field, it was susceptible to Euler beam buckling. However, the classic supercritical bifurcation associated with this buckling became subcritical when an attracting magnet was introduced in close proximity to the beam. To understand these experiments, we develop a model that couples the Euler elastica and dipole magnetic interactions with a uniform external field. The numerical model captures the observed behaviour well and shows that the supercritical magnetic field strength depends almost exclusively on elastic properties of the beam and strength of the permanent magnet, whereas the subcritical behaviour also depends on the separation distance between the attracting pair of magnets. We examine the bifurcation behaviour of the nonlinear system and show that for sufficiently small inter-magnet separation distances, other buckled states coexist with the fundamental mode.