Prospective comparison of two methods for assessing sarcopenia and interobserver agreement on retrospective CT images

PURPOSE OF THE STUDY

To compare the relationships between two CT derived sarcopenia assessment methods, and compare their relationship with inter-rater and intrarater validations and colorectal surgical outcomes.

STUDY DESIGN

157 CT scans were identified across Leeds Teaching Hospitals National Health Service Trust for patients undergoing colorectal cancer surgery. 107 had body mass index data available, required to determine sarcopenia status. This work explores the relationship between sarcopenia, as measured by both total cross sectional-area (TCSA) and psoas-area (PA) and surgical outcomes. All images were assessed for inter-rater and intrarater variability for both TCSA and PA methods of sarcopenia identification. The raters included a radiologist, an anatomist and two medical students.

RESULTS

Prevalence of sarcopenia was different when measured by PA (12.2%-22.4%) in comparison to TCSA (60.8%-70.1%). Strong correlation exists between muscle areas in both TCSA and PA measures, however, there were significant differences between methods after the application of method-specific cut-offs. There was substantial agreement for both intrarater and inter-rater comparisons for both TCSA and PA sarcopenia measures. Outcome data were available for 99/107 patients. Both TCSA and PA have poor association with adverse outcomes following colorectal surgery.

CONCLUSIONS

CT-determined sarcopenia can be identified by junior clinicians, those with anatomical understanding and radiologists. Our study identified sarcopenia to have a poor association with adverse surgical outcomes in a colorectal population. Published methods of identifying sarcopenia are not translatable to all clinical populations. Currently available cut-offs require refinement for potential confounding factors, to provide more valuable clinical information.

WHAT IS ALREADY KNOWN ON THIS TOPIC?

WHAT DOES THIS STUDY ADD?

HOW MIGHT THIS STUDY AFFECT RESEARCH, PRACTICE OR POLICY?

Internal checkpoint regulates T cell neoantigen reactivity and susceptibility to PD1 blockade

BACKGROUND

Adoptive transfer of tumor-infiltrating lymphocytes (TIL) fails to consistently elicit tumor rejection. Manipulation of intrinsic factors that inhibit T cell effector function and neoantigen recognition may therefore improve TIL therapy outcomes. We previously identified the cytokine-induced SH2 protein (CISH) as a key regulator of T cell functional avidity in mice. Here, we investigate the mechanistic role of CISH in regulating human T cell effector function in solid tumors and demonstrate that CRISPR/Cas9 disruption of CISH enhances TIL neoantigen recognition and response to checkpoint blockade.

METHODS

Single-cell gene expression profiling was used to identify a negative correlation between high CISH expression and TIL activation in patient-derived TIL. A GMP-compliant CRISPR/Cas9 gene editing process was developed to assess the impact of CISH disruption on the molecular and functional phenotype of human peripheral blood T cells and TIL. Tumor-specific T cells with disrupted Cish function were adoptively transferred into tumor-bearing mice and evaluated for efficacy with or without checkpoint blockade.

FINDINGS

CISH expression was associated with T cell dysfunction. CISH deletion using CRISPR/Cas9 resulted in hyper-activation and improved functional avidity against tumor-derived neoantigens without perturbing T cell maturation. Cish knockout resulted in increased susceptibility to checkpoint blockade in vivo.

CONCLUSIONS

CISH negatively regulates human T cell effector function, and its genetic disruption offers a novel avenue to improve the therapeutic efficacy of adoptive TIL therapy.

FUNDING

This study was funded by Intima Bioscience, U.S. and in part through the Intramural program CCR at the National Cancer Institute.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Prospective comparison of two methods for assessing sarcopenia and interobserver agreement on retrospective CT images

PURPOSE OF THE STUDY

To compare the relationships between two CT derived sarcopenia assessment methods, and compare their relationship with inter-rater and intrarater validations and colorectal surgical outcomes.

STUDY DESIGN

157 CT scans were identified across Leeds Teaching Hospitals National Health Service Trust for patients undergoing colorectal cancer surgery. 107 had body mass index data available, required to determine sarcopenia status. This work explores the relationship between sarcopenia, as measured by both total cross sectional-area (TCSA) and psoas-area (PA) and surgical outcomes. All images were assessed for inter-rater and intrarater variability for both TCSA and PA methods of sarcopenia identification. The raters included a radiologist, an anatomist and two medical students.

RESULTS

Prevalence of sarcopenia was different when measured by PA (12.2%-22.4%) in comparison to TCSA (60.8%-70.1%). Strong correlation exists between muscle areas in both TCSA and PA measures, however, there were significant differences between methods after the application of method-specific cut-offs. There was substantial agreement for both intrarater and inter-rater comparisons for both TCSA and PA sarcopenia measures. Outcome data were available for 99/107 patients. Both TCSA and PA have poor association with adverse outcomes following colorectal surgery.

CONCLUSIONS

CT-determined sarcopenia can be identified by junior clinicians, those with anatomical understanding and radiologists. Our study identified sarcopenia to have a poor association with adverse surgical outcomes in a colorectal population. Published methods of identifying sarcopenia are not translatable to all clinical populations. Currently available cut-offs require refinement for potential confounding factors, to provide more valuable clinical information.

WHAT IS ALREADY KNOWN ON THIS TOPIC?

WHAT DOES THIS STUDY ADD?

HOW MIGHT THIS STUDY AFFECT RESEARCH, PRACTICE OR POLICY?

Human iPSC-derived hepatocyte system models cholestasis with tight junction protein 2 deficiency

Background & Aims

The truncating mutations in tight junction protein 2 (TJP2) cause progressive cholestasis, liver failure, and hepatocyte carcinogenesis. Due to the lack of effective model systems, there are no targeted medications for the liver pathology with TJP2 deficiency. We leveraged the technologies of patient-specific induced pluripotent stem cells (iPSC) and CRISPR genome-editing, and we aim to establish a disease model which recapitulates phenotypes of patients with TJP2 deficiency.

Methods

We differentiated iPSC to hepatocyte-like cells (iHep) on the Transwell membrane in a polarized monolayer. Immunofluorescent staining of polarity markers was detected by a confocal microscope. The epithelial barrier function and bile acid transport of bile canaliculi were quantified between the two chambers of Transwell. The morphology of bile canaliculi was measured in iHep cultured in the Matrigel sandwich system using a fluorescent probe and live-confocal imaging.

Results

The iHep differentiated from iPSC with TJP2 mutations exhibited intracellular inclusions of disrupted apical membrane structures, distorted canalicular networks, altered distribution of apical and basolateral markers/transporters. The directional bile acid transport of bile canaliculi was compromised in the mutant hepatocytes, resembling the disease phenotypes observed in the liver of patients.

Conclusions

Our iPSC-derived in vitro hepatocyte system revealed canalicular membrane disruption in TJP2 deficient hepatocytes and demonstrated the ability to model cholestatic disease with TJP2 deficiency to serve as a platform for further pathophysiologic study and drug discovery.

Lay summary

We investigated a genetic liver disease, progressive familial intrahepatic cholestasis (PFIC), which causes severe liver disease in newborns and infants due to a lack of gene called TJP2. By using cutting-edge stem cell technology and genome editing methods, we established a novel disease modeling system in cell culture experiments. Our experiments demonstrated that the lack of TJP2 induced abnormal cell polarity and disrupted bile acid transport. These findings will lead to the subsequent investigation to further understand disease mechanisms and develop an effective treatment.

Reduced purine biosynthesis in humans after their divergence from Neandertals

We analyze the metabolomes of humans, chimpanzees, and macaques in muscle, kidney and three different regions of the brain. Although several compounds in amino acid metabolism occur at either higher or lower concentrations in humans than in the other primates, metabolites downstream of adenylosuccinate lyase, which catalyzes two reactions in purine synthesis, occur at lower concentrations in humans. This enzyme carries an amino acid substitution that is present in all humans today but absent in Neandertals. By introducing the modern human substitution into the genomes of mice, as well as the ancestral, Neandertal-like substitution into the genomes of human cells, we show that this amino acid substitution contributes to much or all of the reduction of de novo synthesis of purines in humans.

Prevalence of frailty and reliability of established frailty instruments in adult elective colorectal surgical patients: a prospective cohort study

PURPOSE

Large population studies now demonstrate that frailty is prevalent in all adult age groups. Limited data exist on the association between frailty and surgical outcome in younger patients. The aim of the study was to explore the agreement between frailty identification tools and collect pilot data on their predictive value for frailty-associated outcomes in an adult surgical population.

STUDY DESIGN

Prospective cohort study.

RESULTS

Frailty scores were recorded in 200 patients (91 men), mean (range) age 57 (18-92) years. The prevalence of prefrailty was 52%-67% and that of frailty 2%-32% depending on the instrument used. Agreement between the instruments was poor, kappa 0.08-0.17 in pairwise comparisons. Outcome data were available on 160 patients. Only the frailty phenotype was significantly associated with adverse outcomes, RR 6.1 (1.5-24.5) for postoperative complications. The three frailty scoring instruments studies had good sensitivity (Clinical Frailty Scale (CFS)-90%, Accumulation Deficit (AD)-96%, Frailty Phenotype (FP)-97%) but poor specificity (CFS-12%, AD-13%, FP-18%) for the prediction of postoperative complications. All three instruments were poorly predictive of adverse outcomes with likelihood ratios of CFS-1.02, AD-1.09 and FP-1.17.

CONCLUSIONS

This study showed a significant prevalence of prefrailty and frailty in adult colorectal surgical patients of all ages. There was poor agreement between three established frailty scoring instruments. Our data do not support the use of current frailty scoring instruments in all adult colorectal surgical patients. However, the significant prevalence of prefrailty and frailty across all age groups of adult surgical patient justifies further research to refine frailty scoring in surgical patients.

Abstract LB-087: Discovery and development of first-in-class orally bioavailable USP19 inhibitors

Over the past decade, protein ubiquitination has emerged as an important post-translational modification with regulatory functions in all important cellular processes. Deubiquitinating enzymes (DUBs) including ubiquitin specific proteases (USPs) catalyse the de-ubiquitination of protein substrates, hence regulating their levels and/or function. As a result of their increasing implications in the aetiology of numerous pathological conditions including cancer, neurodegeneration and metabolic disorders, DUBs represent an attractive and promising target class for the development of innovative medicines with high therapeutic impact. However, despite 15 years of research DUBs have proved largely refractory to drug discovery efforts.

As a result of genetic and other validation studies, USP19 has recently emerged as a potentially important target in muscular atrophy associated with various conditions including cancer, as well as in other disorders involving aberrant protein quality control. Herein, we describe the application of our Ubi-Plex™ drug discovery platform to the identification and optimisation of first in class USP19 inhibitors. Several series of novel, highly potent (e.g. IC50 < 5.0 nM) and reversible USP19 inhibitors have been identified. Further profiling has demonstrated excellent selectivity against a large panel of DUBs and other non-related enzymes (e.g. kinases, proteases). These inhibitors are cell-permeable and exhibit potent target engagement in both cancer and muscle cells with EC50 values < 30 nM. We will describe the development of lead molecules with drug-like properties which have allowed us to establish pharmacological target validation by demonstrating efficacy in a muscle wasting model in vivo. Recent developments in the programme leading to orally available USP19 inhibitors will also be presented. This work further exemplifies the tractability of the DUB target family and reports the discovery and detailed profiling of first-in-class inhibitors of USP19. These findings support the rationale to target USP19 for debilitating muscle wasting disorders associated with various conditions such as cancer, as well as for potentially other therapeutic indications, particularly those associated with aberrant protein quality control.

Citation Format: Xavier Jacq, Gerald Gavory, Colin O'Dowd, Aaron Cranston, Oliver Baker, Christina Bell, Stephanie Burton, Eamon Cassidy, Joana Costa, Ashling Henderson, Matthew Helm, Peter Hewitt, Caroline Hughes, Mary McFarland, Hugues Miel, Lauren Proctor, Shane Roundtree, Rachel Church, Ewelina Rozycka, Mark Wappett, Steven Whitehead, Tim Harrison, Nathalie Bedard, Simon S. Wing. Discovery and development of first-in-class orally bioavailable USP19 inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-087.

The contribution of homology arms to nuclease-assisted genome engineering

Designer nucleases like CRISPR/Cas9 enable fluent site-directed damage or small mutations in many genomes. Strategies for their use to achieve more complex tasks like regional exchanges for gene humanization or the establishment of conditional alleles are still emerging. To optimize Cas9-assisted targeting, we measured the relationship between targeting frequency and homology length in targeting constructs using a hypoxanthine-guanine phosphoribosyl-transferase assay in mouse embryonic stem cells. Targeting frequency with supercoiled plasmids improved steeply up to 2 kb total homology and continued to increase with even longer homology arms, thereby implying that Cas9-assisted targeting efficiencies can be improved using homology arms of 1 kb or greater. To humanize the Kmt2d gene, we built a hybrid mouse/human targeting construct in a bacterial artificial chromosome by recombineering. To simplify the possible outcomes, we employed a single Cas9 cleavage strategy and best achieved the intended 42 kb regional exchange with a targeting construct including a very long homology arm to recombine ∼42 kb away from the cleavage site. We recommend the use of long homology arm targeting constructs for accurate and efficient complex genome engineering, particularly when combined with the simplifying advantages of using just one Cas9 cleavage at the genome target site.

RAC-tagging: Recombineering And Cas9-assisted targeting for protein tagging and conditional analyses

A fluent method for gene targeting to establish protein tagged and ligand inducible conditional loss-of-function alleles is described. We couple new recombineering applications for one-step cloning of gRNA oligonucleotides and rapid generation of short-arm (~1 kb) targeting constructs with the power of Cas9-assisted targeting to establish protein tagged alleles in embryonic stem cells at high efficiency. RAC (Recombineering And Cas9)-tagging with Venus, BirM, APEX2 and the auxin degron is facilitated by a recombineering-ready plasmid series that permits the reuse of gene-specific reagents to insert different tags. Here we focus on protein tagging with the auxin degron because it is a ligand-regulated loss-of-function strategy that is rapid and reversible. Furthermore it includes the additional challenge of biallelic targeting. Despite high frequencies of monoallelic RAC-targeting, we found that simultaneous biallelic targeting benefits from long-arm (>4 kb) targeting constructs. Consequently an updated recombineering pipeline for fluent generation of long arm targeting constructs is also presented.

A multifunctional aqueous channel formed by CFTR

The cystic fibrosis gene product (CFTR) is a complex protein that functions as an adenosine 3,5-monophosphate (cAMP)-stimulated ion channel and possibly as a regulator of intracellular processes. In order to determine whether the CFTR molecule contains a functional aqueous pathway, anion, water, and urea transport were measured in Xenopus oocytes expressing CFTR. Cyclic AMP agonists induced a Cl- conductance of 94 microsiemens and an increase in water permeability of 4 x 10(-4) centimeter per second that was inhibited by a Cl- channel blocker and was dependent on anion composition. CFTR has a calculated single channel water conductance of 9 x 10(-13) cubic centimeter per second, suggesting a pore-like aqueous pathway. Oocytes expressing CFTR also showed cAMP-stimulated transport of urea but not the larger solute sucrose. Thus CFTR contains a cAMP-stimulated aqueous pore that can transport anions, water, and small solutes. The results also provide functional evidence for water movement through an ion channel.

A continuous quality improvement team approach to adverse drug reaction reporting

Crossfunctional teams can generate more new ideas, concepts, and possible solutions than does a department-based process alone. Working collaboratively can increase knowledge of teams using CQI approaches and appropriate tools. CQI produces growth and development at multiple levels resulting from involvement in the process of incremental improvement.

Common-source epidemic of hepatitis due to glazed and iced pastries

Sixty-one clinical cases of hepatitis occurred in Ogemaw County, Michigan, in late April and May 1968. The clustering of cases in time and the high attack rate for persons 10-19 years of age suggested a common source of exposure. Investigation implicated a local bakery, where one of the employees directly involved in the baking had had an icteric illness one month before the outbreak. Comparison of exposure histories of patients versus healthy family members established pastries covered with glaze or icing as the vehicle of infection. The glaze and icing were applied to the pastries after all baking had been completed. During the epidemic, immune serum globulin was given on a community-wide basis. No secondary cases of hepatitis were identified.