Observation of magnet-induced star-like radiation of a plasma created from cancer cells in a laser trap

We present a new phenomenon resulting from the interaction of magnetic beads with cancer cells in a laser trap formed on a slide containing a depression 16.5 mm in diameter and 0.78 mm of maximum depth. This phenomenon includes the apparent formation and expansion of a dark bubble that attracts and incinerates surrounding matter when it explodes, which leads to a plasma emitting intense radiation that has the appearance of a star on a microscopic scale. We have observed the star-like phenomenon for more than 4 years, and the intensity depends on the laser's power. Measuring the laser power of the dark bubble shows the entrapment of electromagnetic energy as it expands.

Microdosimetry of a 62-MeV clinical proton beam with five detectors

In proton therapy, most treatment planning systems (TPS) use a fixed relative biological effectiveness (RBE) of 1.1 all along the depth-dose profile. Innovative TPS are now investigated considering the variability of RBE with radiation quality. New TPS need an experimental verification in the quality assurance (QA) routine in clinics, but RBE data are usually obtained with radiobiological measurements that are time consuming and not suitable for daily QA. Microdosimetry is a useful tool based on physical measurements which can monitor the radiation quality. Several microdosimeters are available in different research institutions, which could potentially be used for the QA in TPS. In this study, the response functions of five detectors in the same 62-MeV proton Spread Out Bragg Peak is compared in terms of spectral distributions and their average values and microdosimetric RBE. Their different response function has been commented and must be considered in the clinical practice.

Torsional strabismus and vertical rectus muscle surgery in thyroid eye disease

PURPOSE

To assess the torsional component in patients with vertical strabismus due to thyroid eye disease (TED) and its course after vertical rectus muscle surgery.

PATIENTS AND METHODS

Retrospective chart review of patients undergoing vertical strabismus surgery for TED between 1998 and 2017, having undergone pre- and postoperative Harms tangent screen examination.

RESULTS

Forty patients (27 women) were identified. A torsional component was present in all patients. Thirty-three patients had a mean excyclotorsion of 4.5° in primary position, increasing to 8.2° in upgaze, associated with restricted elevation. Inferior rectus muscle recession (n=29) reduced the excyclotorsion in all cases. A 4.4° mean incyclotorsion was present in primary position in 7 cases, increasing to 7.1° in downgaze. Superior rectus muscle recession reduced the incyclotorsion in 5/6 cases. The torsional surgical dose-effect relationship was correlated with the amount of preoperative torsion. The field of binocular single vision improved from 6.5% preoperatively to 71.1% after surgery.

CONCLUSIONS

Ocular torsion is common in vertical strabismus secondary to TED and is significantly improved by vertical rectus muscle surgery alone. Surgery should be planned according to vertical deviation and motility limitation, and vertical rectus muscles surgery should be considered the first line of treatment, with selective oblique muscle surgery as a second-line option, which was unnecessary in our series.

Modelling the biodistribution of inhaled gold nanoparticles in rats with interspecies extrapolation to humans

The increasing intentional and non-intentional exposure to nanoparticles (NPs) has raised the interest concerning their fate and biodistribution in the body of animals and humans after inhalation. In this context, Physiologically Based (pharmaco)Kinetic (PBK) modelling has emerged as an in silico approach that simulates the biodistribution kinetics of NPs in the body using mathematical equations. Due to restrictions in data availability, such models are first developed for rats or mice. In this work, we present the interspecies extrapolation of a PBK model initially developed for rats, in order to estimate the biodistribution of inhaled gold NPs (AuNPs) in humans. The extrapolation framework is validated by comparing the model results with experimental data from a clinical study performed on humans for inhaled AuNPs of two different sizes, namely 34 nm and 4 nm. The novelty of this work lies in the extrapolation of a PBK model for inhaled AuNPs to humans and comparison with clinical data. The extrapolated model is in good agreement with the experimental data, and provides insights for the mechanisms of inhaled AuNP translocation to the blood circulation, after inhalation. Finally, the biodistribution of the two sizes of AuNPs in the human body after 28 days post-exposure is estimated by the model and discussed.

Modeling of clearance, retention, and translocation of inhaled gold nanoparticles in rats

Objective: The increasing exposure to gold nanoparticles (AuNPs), due to their wide range of applications, has led to the need for thorough understanding of their biodistribution, following exposure. The objective of this paper is to develop a PBK model in order to study the clearance, retention and translocation of inhaled gold nanoparticles in rats, providing a basis for the understanding of the absorption, distribution, metabolism and elimination (ADME) mechanisms of AuNPs in various organs.Materials and methods: A rat PBK computational model was developed, connected to a detailed respiratory model, including the olfactory, tracheobronchial, and alveolar regions. This model was coupled with a Multiple Path Particle Dosimetry (MPPD) model to appropriately simulate the exposure to AuNPs. Three existing in vivo experimental datasets from scientific literature for the biodistribution of inhaled AuNPs for different AuNP sizes and exposure scenarios were utilized for model calibration and validation.Results and Discussion: The model was calibrated using two individual datasets for nose only inhaled and intratracheally instilled AuNPs, while an independent dataset for nose only inhaled AuNPs was used as external validation. The overall fitting over the three datasets was proved acceptable as shown by the relevant statistical metrics. The influence of several physiological parameters is also studied via a sensitivity analysis, providing useful insights into the mechanisms of NP pharmacokinetics. The key aspects of the inhaled AuNPs biodistribution are discussed, revealing the key mechanisms for the AuNPs absorption routes, the AuNP uptake by secondary organs and the influence of the AuNP size on the translocation from the lungs to blood circulation.Conclusions: The model results together with the model sensitivity analysis clarified the key mechanisms for the inhaled AuNPs biodistribution to secondary organs. It was observed that nose-only inhaled AuNPs of smaller size can enter the blood circulation through secondary routes, such as absorption through the gastrointestinal (GI) lumen, showing that such translocations should not be underestimated in biodistribution modelling. Finally, the computational framework presented in this study can be used as a basis for a more wide investigation of inhaled nanoparticles biodistribution, including interspecies extrapolation of the resulting PBK model for the inhalation and subsequent biodistribution of AuNPs in humans.

Developing a multi-disciplinary program for routine acetylcholine vasoreactivity testing in the cardiac catheterization laboratory

Background/Introduction

Of the patients who are referred for invasive coronary angiography 30–50% are found to have no obstructive coronary artery disease. Current ESC Guidelines for chronic coronary syndromes have a class IIa recommendation for intracoronary provocative testing with acetylcholine in patients with ischemia and no obstructive coronary artery disease (INOCA). However, there is limited guidance for pharmacy and nursing teams for the support of provocative testing in the cardiac catheterization laboratory.

Purpose

To demonstrate feasibility and safety of acetylcholine vasoreactivity testing in the cardiac catheterization laboratory.

Methods

The inpatient pharmacy developed an adapted protocol based on available evidence and facilitated a multi-disciplinary operational workflow for the assessment of vasospastic angina. 3mL acetylcholine aliquots of 1mcg/mL, 10 mcg/mL, 25 mcg/mL, 50 mcg/mL, and 100 mcg/mL were prepared by pharmacy following sterile compounding standards. The transition from provider or nursing staff compounding to pharmacy compounding provided quality assurance following United States Pharmacopeia compounding standards for improved sterility and patient safety, especially with a complicated micro-dilution recipe. Pharmacy supported the necessary guidance with optimized clinical decision support in the form of a customized order panel embedded in the electronic health record system and compounding software as another layer of standardization and quality assurance. Syringes were made available to the interventional cardiologist in the cardiac catheterization laboratory suite immediately prior to a scheduled case. Eleven orders of acetylcholine were placed with five dilution syringes per order (total 55 compounded syringes) from the customized acetylcholine provoked coronary vasospasm procedure order panel.

Results

From January 2020 to March 2021, 11 patients underwent acetylcholine vasoreactivity testing for clinical indications. One patient developed atrial fibrillation with a rapid ventricular rate during provocative testing of the right coronary artery which required elective cardioversion the following day. Of 11 patients, 9 were outpatients and 2 were inpatients. 1 patient received intravenous atropine and ondansetron due to profound bradycardia and nausea after 100mcg acetylcholine administration. No other safety events occurred.

Conclusion(s)

Provocative testing with intracoronary acetylcholine administration is safe and feasible. For clinical assessment, sterile compounding and customized order panels facilitate routine clinical assessment for patients with suspected vasospastic angina. Nursing protocols should include cardiac monitoring, medications to reverse adverse effects, and possible outcomes of provocative testing. We provide a practical description of our workflow for pharmacists, catheterization laboratory staff, and providers for routine acetylcholine provocation for the evaluation of INOCA.

Funding Acknowledgement

Type of funding sources: None.

Lack of Increase in Muscle Mitochondrial Protein Synthesis During the Course of Aerobic Exercise and Its Recovery in the Fasting State Irrespective of Obesity

Acute aerobic exercise induces skeletal muscle mitochondrial gene expression, which in turn can increase muscle mitochondrial protein synthesis. In this regard, the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), is a master regulator of mitochondrial biogenesis, and thus mitochondrial protein synthesis. However, PGC-1α expression is impaired in muscle of humans with obesity in response to acute aerobic exercise. Therefore, we sought to determine whether muscle mitochondrial protein synthesis is also impaired under the same conditions in humans with obesity. To this end, we measured mitochondrial and mixed-muscle protein synthesis in skeletal muscle of untrained subjects with (body fat: 34.7 ± 2.3%) and without (body fat: 25.3 ± 3.3%) obesity in a basal period and during a continuous period that included a 45 min cycling exercise (performed at an intensity corresponding to 65% of heart rate reserve) and a 3-h post-exercise recovery. Exercise increased PGC-1α mRNA expression in muscle of subjects without obesity, but not in subjects with obesity. However, muscle mitochondrial protein synthesis did not increase in either subject group. Similarly, mixed-muscle protein synthesis did not increase in either group. Concentrations of plasma amino acids decreased post-exercise in the subjects without obesity, but not in the subjects with obesity. We conclude that neither mitochondrial nor mixed-muscle protein synthesis increase in muscle of humans during the course of a session of aerobic exercise and its recovery period in the fasting state irrespective of obesity. Trial Registration: The study has been registered within ClinicalTrials.gov (NCT01824173).

Microdosimetry of a therapeutic proton beam with a mini-TEPC and a MicroPlus-Bridge detector for RBE assessment

Proton beams are widely used worldwide to treat localized tumours, the lower entrance dose and no exit dose, thus sparing surrounding normal tissues, being the main advantage of this treatment modality compared to conventional photon techniques. Clinical proton beam therapy treatment planning is based on the use of a general relative biological effectiveness (RBE) of 1.1 along the whole beam penetration depth, without taking into account the documented increase in RBE at the end of the depth dose profile, in the Bragg peak and beyond. However, an inaccurate estimation of the RBE can cause both underdose or overdose, in particular it can cause the unfavourable situation of underdosing the tumour and overdosing the normal tissue just beyond the tumour, which limits the treatment success and increases the risk of complications. In view of a more precise dose delivery that takes into account the variation of RBE, experimental microdosimetry offers valuable tools for the quality assurance of LET or RBE-based treatment planning systems. The purpose of this work is to compare the response of two different microdosimetry systems: the mini-TEPC and the MicroPlus-Bridge detector. Microdosimetric spectra were measured across the 62 MeV spread out Bragg peak of CATANA with the mini-TEPC and with the Bridge microdosimeter. The frequency and dose distributions of lineal energy were compared and the different contributions to the spectra were analysed, discussing the effects of different site sizes and chord length distributions. The shape of the lineal energy distributions measured with the two detectors are markedly different, due to the different water-equivalent sizes of the sensitive volumes: 0.85 μm for the TEPC and 17.3 μm for the silicon detector. When the Loncol's biological weighting function is applied to calculate the microdosimetric assessment of the RBE, both detectors lead to results that are consistent with biological survival data for glioma U87 cells. Both the mini-TEPC and the MicroPlus-Bridge detector can be used to assess the RBE variation of a 62 MeV modulated proton beam along its penetration depth. The microdosimetric assessment of the RBE based on the Loncol's weighting function is in good agreement with radiobiological results when the 10% biological uncertainty is taken into account.

SAT0187 DISCRIMINATION OF SYSTEMIC LUPUS (SLE) PATIENTS WITH CLINICAL RESPONSE TO OBEXELIMAB (XMAB®5871) BASED ON A PATTERN OF IMMUNOLOGIC MARKERS

Background:

We recently reported Phase 2 SLE trial results of obexelimab, an FcγRIIb agonist (suppressor of B cell activation). Obexelimab did not meet the primary endpoint (% of patients without flare at Day 225) (p=0.183) but other endpoints such as time to flare (p=0.025) were met.

Objectives:

1. To assign SLE patients to phenotypic subsets based on patterns of gene expression in immune-related pathways.12. To explore the association of immune patterns and clinical response to obexelimab.

Methods:

This analysis included 71 of the 104 participants in the obexelimab study, those who either completed the protocol or terminated for disease flare, if there were adequate blood samples (biomarker subset). At screening, patients were assigned to clusters based on 41 SLE co-expression signature modules from the Human Immune Phenotyping Consortium via unsupervised random forest and K-means clustering.2Other markers of SLE disease were also examined. TheBOLD3study design mandated withdrawal of background immunosuppressants, supporting less ambiguous pharmacodynamic analysis as the trial progressed.

Results:

Immune pathway expression patterns of 7 patient clusters (Fig 1a) confirmed our prior characterization of 200 non-overlapping SLE patients.2The biomarker subset retained a trend of longer time to first flare in patients receiving obexelimab (n=38) vs placebo (n=33) (Fig1b, HR 0.61, p=0.11). A smaller set of only Clusters 3 and 6 demonstrated marked increased time to flare in the obexelimab group (n=13) compared to placebo (n=14) (Fig 1c, HR 0.22, p=0.025). Obexelimab had no effect on other clusters (Fig 1d). The responder clusters shared low expression of inflammation modules (p < 0.001) compared to other clusters and high expression of T Cell, immune response, cell cycle, mitochondrial modules (all p < 0.001) and B Cell modules (p=0.006). We therefore sorted patients by these specific features regardless of cluster assignment. Figure 2 shows significant impact of obexelimab on time to flare in 64 patients with B Cell pathway activation (HR 0.5, p=0.038), although less robust by itself than found in Clusters 3 and 6. In a group with high B or plasma cell modules but low inflammation (n=46), treatment effect increased (HR 0.35, p=0.019). Between Screening and Baseline, as brief steroids were given and background treatments withdrawn, expression of B Cell and Plasma Cell pathways increased. Both then decreased after treatment with obexelimab but not placebo (p< 0.0001 and p< 0.001 respectively), an effect not seen with other immune pathway modules.

Conclusion:

Precision medicine for SLE has been hampered by heterogenous immune signals with variable expression. Clustering of patients by gene co-expression pathways enabled an efficient, hierarchical array that reduplicated results of a prior SLE cohort, suggesting these are not random phenotypes. Of these 7 reproducible SLE subsets, the combination of clusters 3 and 6 distinguished an obexelimab responder population of 27 out of 71 subjects (38%) with high expression of B and T Cell modules and cell activation pathways. Focus on the defining features shared by these clusters revealed specific factors associated with response, enabling inclusion of some patients from other clusters in an optimized responder population of 46/71 (65% of subjects). B Cell and Plasma Cell pathways demonstrated mechanism-related pharmacodynamic effects of obexelimab. Lack of responders with high expression of inflammation modules could implicate inhibitory factors to obexelimab within inflammatory pathways, potentially targetable by complementary treatments.

References:

[1]Banchereau Cell 165:1548 2016

[2]Lu ACR Abstract #2977 2017

[3]Merrill Arthritis Rheumatol 69: 1257 2017

Disclosure of Interests: :

Joan T Merrill Grant/research support from: Xencor, Bristol Myers Squibb, Glaxo Smith Kline, Consultant of: Xencor, Abbvie, UCB, Glaxo Smith Kline, EMD Serono, Astellas, Remegen, Celgene/Bristol Myers Squibb, Exagen, Astra Zeneca, Amgen, Jannsen, Servier, ILTOO, Daitchi Sankyo, Lilly, Paid instructor for: Abbvie, Bristol Myers Squibb, Joel Guthridge Grant/research support from: Xencor, Bristol Myers Squibb, DXterity, Debra Zack Shareholder of: Xencor, Employee of: Xencor, Paul Foster Shareholder of: Xencor Inc, Employee of: Xencor Inc, Bart Burington Shareholder of: Xencor Inc, Employee of: Xencor Inc, Ly Tran: None declared, Miles Smith: None declared, Judith A. James Grant/research support from: Progentec Diagnostics, Inc, Consultant of: Abbvie, Novartis, Jannsen

0829 Sleep, Chronic Pain, and Global Health in Adults Ages 65 or Older

Introduction

Understanding the association of sleep and pain in older adults can help improve their global health. The purpose of the study was to describe the associations between sleep, chronic pain, and global health in adults ages 65 or older.

Methods

This study was a secondary analysis of data from adults over 65 years in the 2015 Sleep in America Poll - Sleep and Pain by the National Sleep Foundation (NSF). The survey included demographics (age, race, marital status, education), sleep (duration, quality, insomnia symptoms), and pain (type [none, chronic, fleeting], intensity, location). Global health derived from general health, physical health, mental health, and quality of life with a potential range of 4-20; higher score=better health. The survey also queried fatigue and stress.

Results

The sample (N=248) was 65-91 years (mean age=72.8±5.9), male (53.6%), White (82.7%), married (65.7%), and with post-highschool education (54.4%). Average sleep duration was 425±74 minutes. “No pain” was reported by 38.7% of the sample (n=96), “fleeting pain” by 32.7% (n= 81), and “chronic pain” by 28.6% (n=71). The most common locations for chronic pain were shoulder or neck (63.2%) and back (69.4%). Average global health score was 9.8±2.9. There was no significant difference in time in bed, sleep duration, bedtime, or wake-up time between groups. Persons with chronic pain had higher average pain intensity, worst pain intensity, and current pain; they reported significantly lower sleep quality with significantly more restlessness, trouble staying asleep, and worry about getting a good night sleep (all p-values&lt;.02), there was no significant difference in difficulty falling asleep compared to persons with no pain. Persons with chronic pain had significantly worse general health, physical health, mental health, global health, fatigue, and stress (all p-values&lt;.02); but no significant difference in quality of life compared to persons with no pain.

Conclusion

We conclude that chronic pain has a significant negative impact on sleep and global health in the sample of adults ages 65 or older from the 2015 Sleep in America Poll - Sleep and Pain by the NSF.

Support

Undergraduate Research Mentoring Program, University of Pittsburgh School of Nursing.

0640 Initial Sleep Center Evaluation and Follow Up Improves Positive Airway Pressure (PAP) Therapy Adherence When Compared to Direct Referrals Without Sleep Physician Follow Up: A Retrospective Study

Introduction

Obstructive sleep apnea (OSA) affects 26% of adults and positive airway pressure (PAP) is the gold-standard of therapy. Factors affecting PAP adherence—use &gt;4 hours in a 24-hour period—have been studied extensively. We compared of the three months (or other time frame) PAP adherence between patients seen by a sleep specialist prior to OSA diagnosis versus patients referred directly for OSA testing by non-sleep specialist providers. The goal of the study was to understand the impact of sleep consultation on PAP adherence.

Methods

Direct referral (DR) patients underwent polysomnography (PSG) and received PAP devices prior to the sleep clinic visit. In contrast, sleep center patients (SC) had a sleep clinic visit with a sleep physician or APRN prior to PSG.

Eighty-four patients were included in this study, 42 DR and 42 SC patients. Exclusion criteria were age &lt;18 years old, absence of baseline PSG, and lack of 90-day compliance data. Covariates included demographics, body mass index (BMI), AHI, nadir oxygen saturation, demographics, and Epworth Sleepiness Scale (ESS) score. Objective PAP adherence for first 90 days was the primary outcome.

Results

Age (p=0.1), ESS (p=0.3), BMI (p=0.6), and AHI (p=0.9) were not significantly different between the groups. SC patients had greater PAP adherence (4.77 hours, 95%CI: 4.1 to 5.4) compared to DR patients (3.61 hours, 95%CI: 2.88 to 4.33, p=0.02). SC patients were also 8 times more likely to follow up in clinic within 1 year of starting PAP treatment (Likelihood Ratio 8.25, p=0.004).

Conclusion

While possibly more time-efficient for patients, direct referrals may ultimately result in lower PAP adherence due to missed opportunities for receiving education about OSA and PAP therapy. This is consistent with findings from a previous meta-analysis demonstrating that educational interventions improve PAP adherence. Moving forward, we will continue encouraging directly referred patients to follow up in the sleep center after PSG.

Support

None

SOI microdosimetry and modified MKM for evaluation of relative biological effectiveness for a passive proton therapy radiation field

With more patients receiving external beam radiation therapy with protons, it becomes increasingly important to refine the clinical understanding of the relative biological effectiveness (RBE) for dose delivered during treatment. Treatment planning systems used in clinics typically implement a constant RBE of 1.1 for proton fields irrespective of their highly heterogeneous linear energy transfer (LET). Quality assurance tools that can measure beam characteristics and quantify or be indicative of biological outcomes become necessary in the transition towards more sophisticated RBE weighted treatment planning and for verification of the Monte Carlo and analytical based models they use. In this study the RBE for the CHO-K1 cell line in a passively delivered clinical proton spread out Bragg peak (SOBP) is determined both in vitro and using a silicon-on-insulator (SOI) microdosimetry method paired with the modified microdosimetric kinetic model. The RBE along the central axis of a SOBP with 2 Gy delivered at the middle of the treatment field was found to vary between 1.11-1.98 and the RBE for 10% cell survival between 1.07-1.58 with a 250 kVp x-ray reference radiation and between 1.19-2.34 and 0.95-1.41, respectively, for a Co60 reference. Good agreement was found between RBE values calculated from the SOI-microdosimetry-MKM approach and in vitro. A strong correlation between proton lineal energy and RBE was observed particularly in the distal end and falloff of the SOBP.

Mitochondrial ATP synthase β-subunit production rate and ATP synthase specific activity are reduced in skeletal muscle of humans with obesity

NEW FINDINGS

What is the central question of this study? Humans with obesity have lower ATP synthesis in muscle along with lower content of the β-subunit of the ATP synthase (β-F1-ATPase), the catalytic component of the ATP synthase. Does lower synthesis rate of β-F1-ATPase in muscle contribute to these responses in humans with obesity? What is the main finding and its importance? Humans with obesity have a lower synthesis rate of β-F₁ -ATPase and ATP synthase specific activity in muscle. These findings indicate that reduced production of subunits forming the ATP synthase in muscle may contribute to impaired generation of ATP in obesity.

ABSTRACT

The content of the β-subunit of the ATP synthase (β-F₁ -ATPase), which forms the catalytic site of the enzyme ATP synthase, is reduced in muscle of obese humans, along with a reduced capacity for ATP synthesis. We studied 18 young (37 ± 8 years) subjects of which nine were lean (BMI = 23 ± 2 kg m^-2 ) and nine were obese (BMI = 34 ± 3 kg m^-2 ) to determine the fractional synthesis rate (FSR) and gene expression of β-F₁ -ATPase, as well as the specific activity of the ATP synthase. FSR of β-F₁ -ATPase was determined using a combination of isotope tracer infusion and muscle biopsies. Gene expression of β-F₁ -ATPase and specific activity of the ATP synthase were determined in the muscle biopsies. When compared to lean, obese subjects had lower muscle β-F₁ -ATPase FSR (0.10 ± 0.05 vs. 0.06 ± 0.03% h^-1 ; P < 0.05) and protein expression (P < 0.05), but not mRNA expression (P > 0.05). Across subjects, abundance of β-F₁ -ATPase correlated with the FSR of β-F₁ -ATPase (P < 0.05). The specific activity of muscle ATP synthase was lower in obese compared to lean subjects (0.035 ± 0.004 vs. 0.042 ± 0.007 arbitrary units; P < 0.05), but this difference was not significant after the activity of the ATP synthase was adjusted to the β-F₁ -ATPase content (P > 0.05). Obesity impairs the synthesis of β-F₁ -ATPase in muscle at the translational level, reducing the content of β-F₁ -ATPase in parallel with reduced capacity for ATP generation via the ATP synthase complex.

Targeted killing of TNFR2-expressing tumor cells and Tregs by TNFR2 antagonistic antibodies in advanced Sézary syndrome

Sézary syndrome (SS) is a rare form of cutaneous T-cell lymphoma often refractory to treatment. SS is defined as adenopathy, erythroderma with high numbers of atypical T cells. This offers an opportunity for new interventions and perhaps antibody-based therapeutic by virtue of its high expression of the TNFR2 oncogene on the tumor cells and on T-regulatory cells (T_regs). Potent human-directed TNFR2 antagonistic antibodies have been created that preferentially target the TNFR2 oncogene and tumor-infiltrating TNFR2⁺ T_regs. Here we test the therapeutic potential of TNFR2 antagonists on freshly isolated lymphocytes from patients with Stage IVA SS and from healthy controls. SS patients were on a variety of end-stage multi-drug therapies. Baseline burden T_reg/T effector (T_eff) ratios and the responsiveness of tumor and infiltrating T_regs to TNFR2 antibody killing was studied. We show dose-escalating concentrations of a dominant TNFR2 antagonistic antibody killed TNFR2⁺ SS tumor cells and thus restored CD26^- subpopulations of lymphocyte cell numbers to normal. The abundant TNFR2⁺ T_regs of SS subjects are also killed with TNFR2 antagonism. Beneficial and rapid expansion of T_eff was observed. The combination of T_reg inhibition and T_eff expansion brought the high T_reg/T_eff ratio to normal. Our findings suggest a marked responsiveness of SS tumor cells and T_regs, to targeting with TNFR2 antagonistic antibodies. These results show TNFR2 antibodies are potent and efficacious in vitro.

Lower Fasted-State but Greater Increase in Muscle Protein Synthesis in Response to Elevated Plasma Amino Acids in Obesity

OBJECTIVE

Obesity alters protein metabolism in skeletal muscle, but consistent evidence is lacking. This study compared muscle protein synthesis in adults with obesity and in lean controls in the fasted state and during an amino acid infusion.

METHODS

Ten subjects with obesity (age: 36 ± 3 years; BMI: 34 ± 1 kg/m² ) and ten controls (age: 35 ± 3 years; BMI: 23 ± 1 kg/m² ) received an infusion of L-[2,3,3,4,5,5,5,6,6,6-² H₁₀ ]leucine (0.15 μmol/kg fat-free mass/min) to measure muscle protein synthesis after an overnight fast and during amino acid infusion.

RESULTS

Despite greater muscle mammalian target of rapamycin phosphorylation (P ≤ 0.05), fasted-state mixed-muscle and mitochondrial protein synthesis were lower in subjects with obesity (P ≤ 0.05). However, the change in mixed-muscle protein synthesis during the amino acid infusion was 2.7-fold greater in subjects with obesity (P ≤ 0.05), accompanied by a greater change in S6 kinase-1 phosphorylation (P ≤ 0.05). The change in mitochondrial protein synthesis did not differ between groups (P > 0.05).

CONCLUSIONS

Adults with obesity have reduced muscle protein synthesis in the fasted state, but this response is compensated for by a greater change in overall muscle protein synthesis during amino acid infusion.

Abstract P2-03-03: A multicenter clinical study of Xpert® breast cancer STRAT4 demonstrates high concordance with central lab ER, PgR, HER2, and Ki67 IHC and HER2 FISH tests in FFPE breast tumor tissues

The Xpert® Breast Cancer STRAT4 (STRAT4) is a CE-IVD marked, semi-quantitative, cartridge-based RT-qPCR assay for the detection of ESR1, PGR, ERBB2 (HER2), and MKi67 mRNAs from formalin fixed, paraffin embedded (FFPE) breast tumors. The assay is fast (&lt; 2 hrs), reproducible, robust, and easy to perform.

The aim of this multicenter clinical study was to assess the performance characteristics of the STRAT4 assay relative to central lab immunohistochemistry (IHC) for ER, PgR, HER2, and Ki67 and to fluorescence in situ hybridization (FISH) for HER2 gene amplification.

Methods: A total of 200 archived primary invasive breast cancer FFPE blocks were sourced from Indivumed for this study. From each block, twelve (12) adjacent tissue sections (4-µm thickness) on slides were prepared for pathological H&E confirmation to define tumor area, and for testing by STRAT4, IHC (ER, PgR, HER2,Ki67), and HER2 FISH. Standard STRAT4 lysate preparation using a single unstained slide per specimen and testing on N=84, N=68, and N=48 samples was performed at 3 independent sites, respectively (2 US and 1 EU). A single slide from each specimen was also processed using the recommended concentrated lysate procedure for STRAT4 testing at Cepheid. All IHC and FISH testing was performed by a central academic reference laboratory in the US. For a given sample, STRAT4 data generated using the standard lysate procedure was included for concordance analysis when all target gene test results were valid. In cases where the standard lysate preparation yielded indeterminate test results for any target, data from the concentrated lysate preparation was used for the data analysis. Receiver Operating Characteristic (ROC) analysis, overall percent agreement (OPA), positive percent agreement (PPA), and negative percent agreement (NPA) between STRAT4 and IHC (IHC/FISH for HER2) were determined for ESR1,PGR, ERBB2, and MKi67.

Results: Of the 200 samples tested by STRAT4, all samples generated valid results for ESR1 and ERBB2, 199 of 200 samples were valid for PGR, and 198 of 200 samples were valid for MKi67 using the standard or concentrated lysate preparation protocol. One sample failed to generate results for both ER and PgR IHC. Twelve samples failed to yield HER2 FISH results.

The STRAT4 success rate and results concordance with IHC were comparable across study sites. OPA between STRAT4 and IHC was 97% for ESR1, 88.9% for PGR, 93.3% for HER2 (92.4% for IHC and FISH), and 90.7% for MKi67 (excluding IHC 10-20% staining). Areas under the ROC curves were 0.9922 for ESR1, 0.9509 for PGR, 0.9958 for ERBB2, and 0.9395 for MKi67.

Conclusion: STRAT4 measurements for ESR1, PGR, ERBB2 and MKi67 mRNA expression are robust and highly concordant with IHC (IHC/FISH for HER2). The technical portion of the assay is easily performed in &lt; 2 hrs including hands-on time using standard FFPE tissue sections. Xpert STRAT4 offers local pathology labs an alternative to centralized, subjective IHC/FISH tests that require a higher level of expertise. Further investigations correlating STRAT4 markers directly with clinical outcomes in independent cohorts are in progress.

Citation Format: Wu NC, Wong E, Acca B, Birkmeier J, Tran L, Zhao S, Wong W, Chu VC, Ho K, Malek M, Lu C, Ge G, David K, Quigley NB, Beqaj SS, Davenport S, Weidler J, Bates M, Press M. A multicenter clinical study of Xpert® breast cancer STRAT4 demonstrates high concordance with central lab ER, PgR, HER2, and Ki67 IHC and HER2 FISH tests in FFPE breast tumor tissues [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-03-03.

Psychological stress-induced colonic barrier dysfunction: Role of immune-mediated mechanisms

BACKGROUND

Evidence suggests that patients with irritable bowel syndrome (IBS) exhibit increases in gut permeability and alterations in tight junction (TJ) protein expression. Although psychological stress worsens IBS symptoms, the mechanisms by which stress enhances gut permeability and affects TJ protein expression remain to be determined. Here, we test the hypothesis that chronic intermittent psychological stress activates the release of proinflammatory cytokines to alter TJ proteins and promotes increased gut permeability.

METHODS

Male Fischer-344 rats were subjected to 1 hour of water avoidance stress (WAS) or SHAM stress per day for 7 days. Following the stress protocol, colonic permeability was measured via transepithelial electrical resistance (TEER) and macromolecular flux of horseradish peroxidase (HRP). In tissue isolated from rats exposed to the WAS or SHAM stress, TJ proteins claudin-2, junctional adhesion molecule-A (JAM-A) and zonula occluden-1 (ZO-1) were measured via Western blotting, histological appearance of the colonic segments was assessed via hematoxylin and eosin staining, and an inflammatory cytokine panel was quantified via quantitative reverse transcription-polymerase chain reaction.

KEY RESULTS

Repetitive daily exposure to WAS decreased the TEER, increased the macromolecular flux of HRP, and altered the expression of claudin-2, JAM-A and ZO-1 proteins within colonic tissue compared to SHAM controls. In the absence of a histologically defined inflammation, the cytokine profiles of WAS-treated animals revealed an increase in interleukin-1β and tumor necrosis factor (TNF)-α. Subsequent analysis revealed a significant positive correlation between TNF-α and expression of TJ protein claudin-2.

CONCLUSIONS & INFERENCES

Our findings suggest that chronic stress increases colonic permeability via sub-inflammatory cytokine-mediated remodeling of TJ protein expression.

Insulin does not stimulate muscle protein synthesis during increased plasma branched-chain amino acids alone but still decreases whole body proteolysis in humans

Insulin stimulates muscle protein synthesis when the levels of total amino acids, or at least the essential amino acids, are at or above their postabsorptive concentrations. Among the essential amino acids, branched-chain amino acids (BCAA) have the primary role in stimulating muscle protein synthesis and are commonly sought alone to stimulate muscle protein synthesis in humans. Fourteen healthy young subjects were studied before and after insulin infusion to examine whether insulin stimulates muscle protein synthesis in relation to the availability of BCAA alone. One half of the subjects were studied in the presence of postabsorptive BCAA concentrations (control) and the other half in the presence of increased plasma BCAA (BCAA). Compared with that prior to the initiation of the insulin infusion, fractional synthesis rate of muscle protein (%/h) did not change (P > 0.05) during insulin in either the control (0.04 ± 0.01 vs 0.05 ± 0.01) or the BCAA (0.05 ± 0.02 vs. 0.05 ± 0.01) experiments. Insulin decreased (P < 0.01) whole body phenylalanine rate of appearance (μmol·kg^-1·min^-1), indicating suppression of muscle proteolysis, in both the control (1.02 ± 0.04 vs 0.76 ± 0.04) and the BCAA (0.89 ± 0.07 vs 0.61 ± 0.03) experiments, but the change was not different between the two experiments (P > 0.05). In conclusion, insulin does not stimulate muscle protein synthesis in the presence of increased circulating levels of plasma BCAA alone. Insulin's suppressive effect on proteolysis is observed independently of the levels of circulating plasma BCAA.

Towards an alternative testing strategy for nanomaterials used in nanomedicine: lessons from NanoTEST

In spite of recent advances in describing the health outcomes of exposure to nanoparticles (NPs), it still remains unclear how exactly NPs interact with their cellular targets. Size, surface, mass, geometry, and composition may all play a beneficial role as well as causing toxicity. Concerns of scientists, politicians and the public about potential health hazards associated with NPs need to be answered. With the variety of exposure routes available, there is potential for NPs to reach every organ in the body but we know little about the impact this might have. The main objective of the FP7 NanoTEST project ( www.nanotest-fp7.eu ) was a better understanding of mechanisms of interactions of NPs employed in nanomedicine with cells, tissues and organs and to address critical issues relating to toxicity testing especially with respect to alternatives to tests on animals. Here we describe an approach towards alternative testing strategies for hazard and risk assessment of nanomaterials, highlighting the adaptation of standard methods demanded by the special physicochemical features of nanomaterials and bioavailability studies. The work has assessed a broad range of toxicity tests, cell models and NP types and concentrations taking into account the inherent impact of NP properties and the effects of changes in experimental conditions using well-characterized NPs. The results of the studies have been used to generate recommendations for a suitable and robust testing strategy which can be applied to new medical NPs as they are developed.

CaMKIIα knockdown decreases anxiety in the open field and low serotonin-induced upregulation of GluA1 in the basolateral amygdala

Hyperactivation of the amygdala is implicated in anxiety and mood disorders, but the precise underlying mechanisms are unclear. We previously reported that depletion of serotonin (5-hydroxytryptamine, 5-HT) in the basolateral nucleus of the amygdala (BLA) using the serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) potentiated learned fear and increased glutamate receptor (Glu) expression in BLA. Here we investigated the hypothesis that CaMKII facilitates anxiety-like behavior and increased Glu/AMPA receptor subunit A1 (GluA1) expression following depletion of 5-HT in the BLA. Infusion of 5,7-DHT into the BLA resulted in anxiety-like behavior in the open field test (OFT) and increased the phosphorylation of CaMKIIα (Thr-286) in the BLA. Knockdown of the CaMKIIα subunit using adeno-associated virus (AAV)-delivered shRNAi concomitantly attenuated anxiety-like behavior in the OFT and decreased GluA1 expression in the BLA. Our results suggest that the CaMKII signaling plays a key role in low 5-HT-induced anxiety and mood disturbances, potentially through regulation of GluA1 expression in the BLA.

Epigenetic modulation of chronic anxiety and pain by histone deacetylation

Prolonged exposure of the central amygdala (CeA) to elevated corticosteroids (CORT) facilitates long-term anxiety and pain through activation of glucocorticoid receptors (GRs) and corticotropin-releasing factor (CRF). However, the mechanisms maintaining these responses are unknown. Since chronic phenotypes can be sustained by epigenetic mechanisms, including histone modifications such as deacetylation, we tested the hypothesis that histone deacetylation contributes to the maintenance of chronic anxiety and pain induced by prolonged exposure of the CeA to CORT. We found that bilateral infusions of a histone deacetylase inhibitor into the CeA attenuated anxiety-like behavior as well as somatic and visceral hypersensitivity resulting from elevated CORT exposure. Moreover, we delineated a novel pathway through which histone deacetylation could contribute to CORT regulation of GR and subsequent CRF expression in the CeA. Specifically, deacetylation of histone 3 at lysine 9 (H3K9), through the coordinated action of the NAD+-dependent protein deacetylase sirtuin-6 (SIRT6) and nuclear factor kappa B (NFκB), sequesters GR expression leading to disinhibition of CRF. Our results indicate that epigenetic programming in the amygdala, specifically histone modifications, is important in the maintenance of chronic anxiety and pain.

A new method to measure muscle protein synthesis in humans by endogenously introduced d9-leucine and using blood for precursor enrichment determination

Enrichment from the easily accessible blood amino acid pool is commonly used as precursor enrichment to calculate rates of muscle protein fractional synthesis in relevant human studies in lieu of the less accessible muscle fluid amino acid pool. However, the accuracy of this approach depends largely on the extent to which there is low discrepancy in free amino acid enrichment between blood and muscle. Steady-state gradient (i.e., ratio) of amino acid enrichment between blood and muscle fluid in the basal state and in response to amino acid infusion were determined in five healthy subjects, and in association with two separate tracers: d9-leucine, introduced endogenously by the metabolism of d10-leucine (i.e., l-[2,3,3,4,5,5,5,6,6,6-(2)H10]leucine) infused in blood, and (13)C6-phenylalanine introduced/infused in blood. The blood-to-muscle fluid amino acid enrichment ratio was lower (P < 0.05) for d9-leucine compared to (13)C6-phenylalanine both before (1.5 ± 0.1 vs. 2.5 ± 0.1) and during (1.1 ± 0.1 vs. 1.2 ± 0.1) amino acid infusion. Importantly, the decrease in this ratio in association with the amino acid infusion was considerably less for the d9-leucine than the (13)C6-phenylalanine (-0.38 ± 0.03 vs. -1.29 ± 0.07; P < 0.05). In conclusion, blood d9-leucine enrichment introduced endogenously by intravenous infusion of d10-leucine provides a closer estimate of the muscle fluid amino acid enrichment, and its associated changes, than blood phenylalanine enrichment to calculate rates of muscle protein synthesis in humans.