Clinical characteristics and outcomes of adrenal hemorrhage

BACKGROUND

Although uncommon, adrenal hemorrhage has multiple etiologies. Because clinical characteristics, management, and outcomes of patients with adrenal hemorrhage are inadequately described, we examined the underlying etiology, need for intervention, evolution of imaging characteristics, and adequacy of subsequent evaluation.

METHODS

We performed a retrospective review of patients diagnosed with adrenal hemorrhage (radiologist-confirmed density consistent with hemorrhage on computed tomography) from 2005 to 2021 at a university-based institution. Demographic characteristics, hemorrhage etiology, and subsequent follow-up were analyzed.

RESULTS

Of 193 adrenal hemorrhage patients, the mean age was 49.2 ± 18.3 years, and 35% were female. Clinical presentations included trauma (47%), abdominal or flank pain (28%), incidental findings on imaging acquired for other reasons (12%), postoperative complication (8%), or shock (3%). Hemorrhage outside of the gland was present in 62% of patients. Unilateral hemorrhage was more frequent (93%) than bilateral (7%). A total of 12% of patients had nodules, but only 70% of these were identified on initial imaging, and only 43% had hormonal evaluation. Of 7 patients who had adrenalectomy or biopsy, pathology was either benign (57%) or nonadrenal malignancy (43%). No adrenocortical carcinomas were identified. Follow-up imaging was performed in 56% of patients and revealed decreased, stable, resolved, or increased adrenal hemorrhage size in 39%, 19%, 30%, and 12% of patients, respectively.

CONCLUSION

Adrenal hemorrhage is secondary to multiple etiologies, most commonly trauma. In the setting of adrenal hemorrhage, many adrenal nodules were not identified on initial imaging. Only a minority of patients with nodules underwent "complete" biochemical evaluation. Follow-up imaging may improve the identification of underlying nodules needing hormonal evaluation.

Bioengineered in vitro three-dimensional tumor models in endocrine cancers

Graphical abstract

Abstract

Endocrine tumors are a heterogeneous cluster of malignancies that originate from cells that can secrete hormones. Examples include, but are not limited to, thyroid cancer, adrenocortical carcinoma, and neuroendocrine tumors. Many endocrine tumors are relatively slow to proliferate, and as such, they often do not respond well to common antiproliferative chemotherapies. Therefore, increasing attention has been given to targeted therapies and immunotherapies in these diseases. However, in contrast to other cancers, many endocrine tumors are relatively rare, and as a result, less is understood about their biology, including specific targets for intervention. Our limited understanding of such tumors is in part due to a limitation in model systems that accurately recapitulate and enable mechanistic exploration of these tumors. While mouse models and 2D cell cultures exist for some endocrine tumors, these models often may not accurately model nuances of human endocrine tumors. Mice differ from human endocrine physiology and 2D cell cultures fail to recapitulate the heterogeneity and 3D architectures of in vivo tumors. To complement these traditional cancer models, bioengineered 3D tumor models, such as organoids and tumor-on-a-chip systems, have advanced rapidly in the past decade. However, these technologies have only recently been applied to most endocrine tumors. In this review we provide descriptions of these platforms, focusing on thyroid, adrenal, and neuroendocrine tumors and how they have been and are being applied in the context of endocrine tumors.

Heterogeneous parathyroid near-infrared autofluorescence patterns are associated with single adenomas in primary hyperparathyroidism

BACKGROUND

Primary adenoma (PA) and multi-gland hyperplasia (MGH) account for 85% and 15% of primary hyperparathyroidism (PHPT) cases, respectively. Near-infrared autofluorescence (NIRAF) enhances intraoperative parathyroid identification. We hypothesized that PA would display a more heterogeneous NIRAF pattern compared to MGH.

METHODS

Patients undergoing surgery for sporadic PHPT were categorized based on the presence of PA or MGH. To quantify heterogeneity, we utilized ratios of (1) mean parathyroid gland (PG) NIRAF over background NIRAF (mean ratio), (2) minimum and (3) maximum PG NIRAF over mean PG NIRAF (minimum and maximum ratios). Additionally, a heterogeneity score was quantified using mean ratio (mean PG NIRAF over background NIRAF), and overall NIRAF (mean NIRAF of eight random 15 × 15 pixel areas). A point was assigned to ratios <0.8 or >1.2. Images were quantified by ImageJ software. Mann-Whitney test was performed for all comparisons.

RESULTS

Of 78 patients, 63 had a single PA and 15 had MGH, totaling 102 PGs. There was no difference between their mean ratios. PA had a lower minimum ratio compared to that of MGH (0.86 ± 0.01 vs. 0.93 ± 0.01, p = 0.001) and a brighter maximum ratio (1.21 ± 0.02 vs. 1.12 ± 0.01, p = 0.0008). PA also scored higher on their heterogeneity scores compared to MGH (1.27 ± 0.23 vs. 0.33 ± 0.15, p = 0.001).

CONCLUSION

Single parathyroid adenomas display a more heterogeneous autofluorescence pattern compared to that of multi-gland hyperplasia. Intraoperative characterization of PGs by real-time NIR imaging patterns may be a beneficial adjunct during parathyroid surgery.

A 3D adrenocortical carcinoma tumor platform for preclinical modeling of drug response and matrix metalloproteinase activity

Adrenocortical carcinoma (ACC) has a poor prognosis, and no new drugs have been identified in decades. The absence of drug development can partly be attributed to a lack of preclinical models. Both animal models and 2D cell cultures of ACC fail to accurately mimic the disease, as animal physiology is inherently different than humans, and 2D cultures fail to represent the crucial 3D architecture. Organoids and other small 3D in vitro models of tissues or tumors can model certain complexities of human in vivo biology; however, this technology has largely yet to be applied to ACC. In this study, we describe the generation of 3D tumor constructs from an established ACC cell line, NCI-H295R. NCI-H295R cells were encapsulated to generate 3D ACC constructs. Tumor constructs were assessed for biomarker expression, viability, proliferation, and cortisol production. In addition, matrix metalloproteinase (MMP) functionality was assessed directly using fluorogenic MMP-sensitive biosensors and through infusion of NCI-H295R cells into a metastasis-on-a-chip microfluidic device platform. ACC tumor constructs showed expression of biomarkers associated with ACC, including SF-1, Melan A, and inhibin α. Treatment of ACC tumor constructs with chemotherapeutics demonstrated decreased drug sensitivity compared to 2D cell culture. Since most tumor cells migrate through tissue using MMPs to break down extracellular matrix, we validated the utility of ACC tumor constructs by integrating fluorogenic MMP-sensitive peptide biosensors within the tumor constructs. Lastly, in our metastasis-on-a-chip device, NCI-H295R cells successfully engrafted in a downstream lung cell line-based construct, but invasion distance into the lung construct was decreased by MMP inhibition. These studies, which would not be possible using 2D cell cultures, demonstrated that NCI-H295R cells secreted active MMPs that are used for invasion in 3D. This work represents the first evidence of a 3D tumor constructs platform for ACC that can be deployed for future mechanistic studies as well as development of new targets for intervention and therapies.

Adrenal Near-Infrared Autofluorescence

Context

Parathyroid tissue is one of the few tissues to have strong near-infrared (NIR) autofluorescence, which has been exploited to improve intraoperative parathyroid identification. The US Food and Drug Administration has approved 2 devices for this purpose. Adrenal glands can be difficult to distinguish from surrounding fat, an issue during total adrenalectomy.

Objective

We hypothesized adrenal tissue may also possess considerable NIR autofluorescence.

Methods

Resected patient adrenal specimens were examined after robotic adrenalectomy with an NIR camera intraoperatively. Patients did not receive fluorescent dye. Images were taken of both gross and sectioned specimens. Post hoc image analysis was performed with ImageJ software. Confocal microscopy was performed on selected tissues using immunofluorescence and hematoxylin-eosin staining.

Results

Resected tissue was examined from 22 patients undergoing surgery for pheochromocytomas (6), primary aldosteronism (3), adrenocorticotropin-independent hypercortisolism (10), and a growing or suspicious mass (3). Normal adrenal tissue demonstrated strong NIR autofluorescence. The intensity ratio compared to background (set as 1) for gross images was 2.03 ± 0.51 (P < .0001) compared to adjacent adipose of 1.24 ± 0.18. Autofluorescence from adrenal tumors was also detected at variable levels of intensity. Cortisol-producing tumors had the highest fluorescence ratio of 3.01 ± 0.41. Confocal imaging localized autofluorescence to the cytosol, with the highest intensity in the zona reticularis followed by the zona fasciculata.

Conclusion

Normal and abnormal adrenal tissues possess natural NIR autofluorescence. Highest autofluorescence levels were associated with cortisol-producing tumors. Confocal imaging demonstrated the highest intensity in the zona reticularis. NIR cameras may have the potential to improve identification of adrenal tissue during surgery.

Vertical sleeve gastrectomy induces enteroendocrine cell differentiation of intestinal stem cells through bile acid signaling

Vertical sleeve gastrectomy (VSG) results in an increase in the number of hormone-secreting enteroendocrine cells (EECs) in the intestinal epithelium; however, the mechanism remains unclear. Notably, the beneficial effects of VSG are lost in a mouse model lacking the nuclear bile acid receptor farnesoid X receptor (FXR). FXR is a nuclear transcription factor that has been shown to regulate intestinal stem cell (ISC) function in cancer models. Therefore, we hypothesized that the VSG-induced increase in EECs is due to changes in intestinal differentiation driven by an increase in bile acid signaling through FXR. To test this, we performed VSG in mice that express EGFP in ISC/progenitor cells and performed RNA-Seq on GFP-positive cells sorted from the intestinal epithelia. We also assessed changes in EEC number (marked by glucagon-like peptide-1, GLP-1) in mouse intestinal organoids following treatment with bile acids, an FXR agonist, and an FXR antagonist. RNA-Seq of ISCs revealed that bile acid receptors are expressed in ISCs and that VSG explicitly alters expression of several genes that regulate EEC differentiation. Mouse intestinal organoids treated with bile acids and 2 different FXR agonists increased GLP-1-positive cell numbers, and administration of an FXR antagonist blocked these effects. Taken together, these data indicate that VSG drives ISC fate toward EEC differentiation through bile acid signaling.

Physician Perspectives of Overdiagnosis and Overtreatment of Low-Risk Papillary Thyroid Cancer in the US

This survey study assesses physicians’ recommendations regarding overdiagnosis and overtreatment of thyroid nodules and low-risk papillary thyroid cancer.

Ambiguous and Incomplete: Natural Language Processing Reveals Problematic Reporting Styles in Thyroid Ultrasound Reports

OBJECTIVE

 Natural language processing (NLP) systems convert unstructured text into analyzable data. Here, we describe the performance measures of NLP to capture granular details on nodules from thyroid ultrasound (US) reports and reveal critical issues with reporting language.

METHODS

 We iteratively developed NLP tools using clinical Text Analysis and Knowledge Extraction System (cTAKES) and thyroid US reports from 2007 to 2013. We incorporated nine nodule features for NLP extraction. Next, we evaluated the precision, recall, and accuracy of our NLP tools using a separate set of US reports from an academic medical center (A) and a regional health care system (B) during the same period. Two physicians manually annotated each test-set report. A third physician then adjudicated discrepancies. The adjudicated "gold standard" was then used to evaluate NLP performance on the test-set.

RESULTS

 A total of 243 thyroid US reports contained 6,405 data elements. Inter-annotator agreement for all elements was 91.3%. Compared with the gold standard, overall recall of the NLP tool was 90%. NLP recall for thyroid lobe or isthmus characteristics was: laterality 96% and size 95%. NLP accuracy for nodule characteristics was: laterality 92%, size 92%, calcifications 76%, vascularity 65%, echogenicity 62%, contents 76%, and borders 40%. NLP recall for presence or absence of lymphadenopathy was 61%. Reporting style accounted for 18% errors. For example, the word "heterogeneous" interchangeably referred to nodule contents or echogenicity. While nodule dimensions and laterality were often described, US reports only described contents, echogenicity, vascularity, calcifications, borders, and lymphadenopathy, 46, 41, 17, 15, 9, and 41% of the time, respectively. Most nodule characteristics were equally likely to be described at hospital A compared with hospital B.

CONCLUSIONS

 NLP can automate extraction of critical information from thyroid US reports. However, ambiguous and incomplete reporting language hinders performance of NLP systems regardless of institutional setting. Standardized or synoptic thyroid US reports could improve NLP performance.

Thyroid cancer, recent advances in diagnosis and therapy

Over the past several decades, the approach to the diagnosis and management of patients with follicular cell-derived thyroid cancer has evolved based on improved classification of patients better matching clinical outcomes, as well as advances in imaging, laboratory, molecular technologies and knowledge. While thyroid surgery, radioactive iodine therapy and TSH suppression remain the mainstays of treatment, this expansion of knowledge has enabled de-escalation of therapy for individuals diagnosed with low-risk well-differentiated thyroid cancer; better definition of treatment choices for patients with more aggressive disease; and improved ability to optimize treatments for patients with persistent and/or progressive disease. Most recently, the advancement of knowledge regarding the molecular aspects of thyroid cancer has improved thyroid cancer diagnosis and has enabled individualized therapeutic options for selected patients with the most aggressive forms of the disease. Guidelines from multiple societies across the world reflect these changes, which focus on taking a more individualized approach to clinical management. In this review, we discuss the current more personalized approach to patients with follicular cell-derived thyroid cancer and point toward areas of future research still needed in the field.

Thyroid Ultrasound Reports: Will the Thyroid Imaging, Reporting, and Data System Improve Natural Language Processing Capture of Critical Thyroid Nodule Features?

BACKGROUND

Critical thyroid nodule features are contained in unstructured ultrasound (US) reports. The Thyroid Imaging, Reporting, and Data System (TI-RADS) uses five key features to risk stratify nodules and recommend appropriate intervention. This study aims to analyze the quality of US reporting and the potential benefit of Natural Language Processing (NLP) systems in efficiently capturing TI-RADS features from text reports.

MATERIALS AND METHOD

This retrospective study used free-text thyroid US reports from an academic center (A) and community hospital (B). Physicians created "gold standard" annotations by manually extracting TI-RADS features and clinical recommendations from reports to determine how often they were included. Similar annotations were created using an automated NLP system and compared with the gold standard.

RESULTS

Two hundred eighty-two reports contained 409 nodules at least 1-cm in maximum diameter. The gold standard identified three nodules (0.7%) which contained enough information to calculate a complete TI-RADS score. Shape was described most often (92.7% of nodules), whereas margins were described least often (11%). A median number of two TI-RADS features are reported per nodule. The NLP system was significantly less accurate than the gold standard in capturing echogenicity (27.5%) and margins (58.9%). One hundred eight nodule reports (26.4%) included clinical management recommendations, which were included more often at site A than B (33.9 versus 17%, P < 0.05).

CONCLUSIONS

These results suggest a gap between current US reporting styles and those needed to implement TI-RADS and achieve NLP accuracy. Synoptic reporting should prompt more complete thyroid US reporting, improved recommendations for intervention, and better NLP performance.

Outcomes after completion thyroidectomy versus total thyroidectomy for differentiated thyroid cancer: A single-center experience

BACKGROUND

Thyroid cancer diagnoses are often discovered after diagnostic thyroid lobectomy. Completion thyroidectomy (CT) may be indicated for intermediate or high-risk tumors to facilitate surveillance and/or adjuvant treatment. The completeness of thyroid resection and the safety of CT compared to total thyroidectomy (TT) is unclear. We assessed outcomes after TT or CT to determine completeness of resection and risk of complications.

METHODS

Patients undergoing TT or CT between 2000 and 2018 were retrospectively reviewed. Pathology, unstimulated thyroglobulin (uTg), parathyroid hormone (PTH), rates of hematoma, and recurrent laryngeal nerve (RLN) injury were compared.

RESULTS

Differentiated thyroid cancer (DTC) was identified in 954 patients undergoing TT and 142 patients undergoing CT. Postoperative uTg at 6 months was not different between TT and CT, 0.2 vs 0.2 ng/mL, P = .37. Transient hypoparathyroidism with immediate postoperative PTH less than 10 was more common after TT, 14.3 vs 6.0% (P = .009). No differences were noted regarding postoperative hematoma, transient RLN injury, permanent hypoparathyroidism, and permanent RLN injury.

CONCLUSIONS

If CT is required for DTC, a complete resection, as assessed by postoperative uTg, can be achieved. Furthermore, CT is significantly less likely to result in transient hypoparathyroidism and poses no additional risk of RLN injury, hematoma, or permanent hypoparathyroidism.

Hormonal Evaluation of Incidental Adrenal Masses: The Exception, Not the Rule

BACKGROUND

Incidental adrenal masses (IAMs) occur in approximately 4% of patients undergoing abdominal CT scans for any indication. Hormonal evaluation is recommended for all IAMs. The purpose of this study was to identify the rate of IAMs in a screening population and to determine the adequacy of endocrine evaluation of newly identified IAMs based on established guidelines.

METHODS

This was a retrospective analysis of 6913 patients undergoing a non-contrast screening CT colonography at a single academic medical center between June 2004 and July 2012.

RESULTS

The prevalence of IAMs in this asymptomatic screening population was 2.1% (n = 148). Of those patients, 8.8% (n = 11) underwent some form of hormonal evaluation and only 6.4% (n = 8) patients had a "complete" workup. Cortisol, metanephrines, and an aldosterone-renin ratio were evaluated in 8.0%, 7.2%, and 4.0% of patients, respectively. Of the patients (n = 11) who underwent hormonal evaluation, 27.3% had functional masses and 36.4% underwent surgery. Of those who did not have hormonal evaluation, 42.1% (n = 48) had comorbidities that should have prompted hormonal evaluation based on established guidelines. Hormonal evaluation was not performed in 89.4% of patients with hypertension and 21.1% of patients with diabetes. 88.9% of patients on three or more antihypertensive medications did not undergo any hormonal evaluation.

CONCLUSIONS

Compliance with IAM workup guidelines is poor, which may result in missed diagnosis of functional adrenal masses. Establishment of a robust protocol and education on appropriate workup for IAMs is necessary for adequate hormonal evaluation.

COVID-19 Pandemic and Surgical Oncology: Preserving the Academic Mission

BACKGROUND

The global pandemic of respiratory disease cause by the novel human coronavirus (SARS-CoV-2) has caused untold suffering, loss of life and upheaval in society. The pandemic has lead to massive redirection of health care resources to treat the surge of COVID-19 patients, and enforcement of social distancing to reduce the rate of transmission.

METHODS

Editorial Board members provided observations of the implications of the pandemic on academic surgical oncology.

RESULTS

Delivery of health care to other populations including cancer patients has been significantly disrupted. The implications both short term and long term threaten preservation of the academic mission in medicine at large, and certainly in the field of surgical oncology.

CONCLUSIONS

The effects on surgical oncology training, research and clinical trials are major.

Telemedicine: Patient-Provider Clinical Engagement During the COVID-19 Pandemic and Beyond

BACKGROUND

The novel coronavirus pandemic has drastically affected healthcare organizations across the globe.

METHODS

We sought to summarize the current telemedicine environment in order to highlight the important changes triggered by the novel coronavirus pandemic, as well as highlight how the current crisis may inform the future of telemedicine.

RESULTS

At many institutions, the number of telemedicine visits dramatically increased within days following the institution of novel coronavirus pandemic restrictions on in-person clinical encounters. Prior to the pandemic, telemedicine utilization was weak throughout surgical specialties due to regulatory and reimbursement barriers. As part of the pandemic response, the USA government temporarily relaxed various telemedicine restrictions and provided additional telemedicine funding.

DISCUSSION

The post-pandemic role of telemedicine is dependent on permanent regulatory solutions. In the coming decade, telemedicine and telesurgery are anticipated to mature due to the proliferation of interconnected consumer health devices and high-speed 5G data connectivity.

Intraoperative Feedback: A Video-BasedAnalysis of Faculty and Resident Perceptions

OBJECTIVE

Residents and faculty identify intraoperative feedback as a critical component of surgical education. Studies have demonstrated that residents perceive lower quality and frequency of intraoperative feedback compared to faculty. These differences in perception may be due to dissimilar identification of feedback. The purpose of this study was to determine if residents and faculty differently identify intraoperative interactions as feedback.

DESIGN

Residents and faculty viewed a segment of a laparoscopic cholecystectomy video and then timestamped the video where they perceived moments of intraoperative feedback. Validated surveys on timing, amount, specificity, and satisfaction with operative feedback were administered.

SETTING

Viewing of the video and survey administration was conducted at the University of Michigan.

PARTICIPANTS

A total of 23 of 41 residents (56%) and 29 of 33 faculty (88%) participated in this study.

RESULTS

Survey analysis demonstrated that residents perceived operative feedback to occur with less immediacy, specificity, and frequency compared to faculty. During the 10-minute video, residents and faculty identified feedback 21 and 29 times, respectively (p = 0.13). Ten-second interval analysis demonstrated 7 statistically significant intervals (p < 0.05) where residents identified feedback less frequently than faculty. Analysis of these 7 intervals revealed that faculty were more likely to identify interactions, especially nonverbal ones, as feedback. Review of free-text comments confirmed these findings and suggested that residents may be more receptive to feedback at the conclusion of the case.

CONCLUSIONS

Using video review, we show that residents and faculty identify different intraoperative interactions as feedback. This disparity in identification of feedback may limit resident satisfaction and effective intraoperative learning. Timing and labeling of feedback, continued use of video review, and structured teaching models may overcome these differences and improve surgical education.

Identification, isolation and characterization of human LGR5-positive colon adenoma cells

The intestine is maintained by stem cells located at the base of crypts and distinguished by the expression of LGR5. Genetically engineered mouse models have provided a wealth of information about intestinal stem cells, whereas less is known about human intestinal stem cells owing to difficulty detecting and isolating these cells. We established an organoid repository from patient-derived adenomas, adenocarcinomas and normal colon, which we analyzed for variants in 71 colorectal cancer (CRC)-associated genes. Normal and neoplastic colon tissue organoids were analyzed by immunohistochemistry and fluorescent-activated cell sorting for LGR5. LGR5-positive cells were isolated from four adenoma organoid lines and were subjected to RNA sequencing. We found that LGR5 expression in the epithelium and stroma was associated with tumor stage, and by integrating functional experiments with LGR5-sorted cell RNA sequencing data from adenoma and normal organoids, we found correlations between LGR5 and CRC-specific genes, including dickkopf WNT signaling pathway inhibitor 4 (DKK4) and SPARC-related modular calcium binding 2 (SMOC2). Collectively, this work provides resources, methods and new markers to isolate and study stem cells in human tissue homeostasis and carcinogenesis.

Reduced paraspinous muscle area is associated with post-colectomy complications in children with ulcerative colitis

BACKGROUND AND OBJECTIVES

Sarcopenia, defined as reduced muscle mass, is typically assessed by CT scans, which are infrequently performed in children. Using MRI to measure sarcopenia, we determined the association with postoperative complications after colectomy for ulcerative colitis (UC).

METHODS

Clinical and preoperative MRI data for 13-18-year-old UC patients who underwent colectomy were retrospectively reviewed. Bilateral paraspinous muscle area (PSMA) and psoas muscle area (PMA) at L3 vertebra were measured and averaged. Composite complications were infection, wound dehiscence, postoperative leak/abscess, prolonged ileus, pulmonary embolism, venous thromboembolism, or readmission.

RESULTS

Twenty-nine patients with average age 15.9±1.36years and weight 61.5±19.8kg had a preoperative MRI. The 18/29(62%) with complications had significantly reduced PSMA (4.71±1.44 vs 5.64±1.38cm2, p=0.04) and PMA (7.16±2.60 vs 8.93±2.44, p=0.04). When stratified and compared to highest PSMA, patients with lowest PSMA had increased complication rates (88% vs 29%, p=0.04). There were no differences in age, BMI, albumin, CRP, ESR, or preoperative steroid or anti-TNFα use. Odds of complication in the lowest tertile were 25.0-fold higher than the highest tertile (p=0.04, 95% CI=1.2-520.73).

CONCLUSION

This is the first study to show low PSMA on MRI is associated with complications and increased hospital stay after colectomy in children with UC.

LEVELS OF EVIDENCE

Level III retrospective comparative study.

Bacterial colonization stimulates a complex physiological response in the immature human intestinal epithelium

The human gastrointestinal tract is immature at birth, yet must adapt to dramatic changes such as oral nutrition and microbial colonization. The confluence of these factors can lead to severe inflammatory disease in premature infants; however, investigating complex environment-host interactions is difficult due to limited access to immature human tissue. Here, we demonstrate that the epithelium of human pluripotent stem-cell-derived human intestinal organoids is globally similar to the immature human epithelium and we utilize HIOs to investigate complex host-microbe interactions in this naive epithelium. Our findings demonstrate that the immature epithelium is intrinsically capable of establishing a stable host-microbe symbiosis. Microbial colonization leads to complex contact and hypoxia driven responses resulting in increased antimicrobial peptide production, maturation of the mucus layer, and improved barrier function. These studies lay the groundwork for an improved mechanistic understanding of how colonization influences development of the immature human intestine.

Macrophage-derived IL-10 mediates mucosal repair by epithelial WISP-1 signaling

In response to injury, epithelial cells migrate and proliferate to cover denuded mucosal surfaces and repair the barrier defect. This process is orchestrated by dynamic crosstalk between immune cells and the epithelium; however, the mechanisms involved remain incompletely understood. Here, we report that IL-10 was rapidly induced following intestinal mucosal injury and was required for optimal intestinal mucosal wound closure. Conditional deletion of IL-10 specifically in CD11c-expressing cells in vivo implicated macrophages as a critical innate immune contributor to IL-10-induced wound closure. Consistent with these findings, wound closure in T cell- and B cell-deficient Rag1-/- mice was unimpaired, demonstrating that adaptive immune cells are not absolutely required for this process. Further, following mucosal injury, macrophage-derived IL-10 resulted in epithelial cAMP response element-binding protein (CREB) activation and subsequent synthesis and secretion of the pro-repair WNT1-inducible signaling protein 1 (WISP-1). WISP-1 induced epithelial cell proliferation and wound closure by activating epithelial pro-proliferative pathways. These findings define the involvement of macrophages in regulating an IL-10/CREB/WISP-1 signaling axis, with broad implications in linking innate immune activation to mucosal wound repair.

Chronic stress and intestinal barrier dysfunction: Glucocorticoid receptor and transcription repressor HES1 regulate tight junction protein Claudin-1 promoter

Chronic stress and elevated glucocorticoid hormone are associated with decreases in the intestinal epithelial tight junction protein claudin-1 (CLDN1). Human/rat CLDN1 promoters contain glucocorticoid response elements (GREs) and adjacent transcription repressor HES1 binding N-boxes. Notch signaling target HES1 expression was high and glucocorticoid receptor (NR3C1) low at the crypt base and the pattern reversed at the crypt apex. Chronic stress reduced overall rat colon HES1 and NR3C1 that was associated with CLDN1 downregulation. Chromatin-immunoprecipitation experiments showed that HES1 and NR3C1 bind to the CLDN1 promoter in rat colon crypts. The binding of NR3C1 but not HES1 to CLDN1 promoter significantly decreased in chronically stressed animals, which was prevented by the NR3C1 antagonist RU486. We employed the 21-day Caco-2/BBe cell model to replicate cell differentiation along the crypt axis. HES1 siRNA treatment early in differentiation increased CLDN1. In contrast, stress levels of cortisol decreased CLDN1 in late differentiation stage but not in the early stage. HES1 was high, whereas NR3C1 and CLDN1 were low in the early stage which reversed in the late stage, e.g. HES1/NR3C1 binding to CLDN1 promoter demonstrates a dynamic and reciprocal pattern. These results suggest that chronic stress impairs colon epithelium homeostasis and barrier function via different mechanisms along the crypt axis.

Abstract LB-093: Simultaneous measurement of global methylation and copy number alterations in human colorectal cancer samples

Epigenomic changes are commonly observed in cancer. We developed a next-generation sequencing (NGS) assay which can identify subtle changes in global methylation as well as copy number alterations (CNAs). The assay measures the methylation level of some repeat elements, covering over 25% of all CpG in the genome.

Genomic DNA extracted from 18 pairs of matched colorectal tumor to normal tissue was tested (four adenocarcinomas, including one associated with inflammatory bowel disease, and fourteen adenomas, including one adenoma from a Lynch syndrome patient, one familial adenomatous polyposis (FAP) and two sessile serrated adenomas (SSA)). We also assayed organoids established from these tissues at early (2 month) and late (more than 6 months) timepoints in culture. Briefly, bisulfite conversion and enrichment of the repeats was performed. The Illumina compatible products were sequenced on a HiSEQ 2500. Analysis was performed using Bismark (Krueger F., Babraham institute) and Nexus copy number (BioDiscovery) to determine the global methylation and the CNAs, respectively. Finally, somatic and germline variants were determined by targeted sequencing of 71 genes using the QIAseq colorectal cancer panel (QIAGEN).

Our data showed that all adenocarcinoma presented hypomethylation and CNAs as well as multiple somatic variants in APC, KRAS, TP53, SMAD4 and PIK3CA. Six out of the fourteen adenomas presented CNAs and nine showed hypomethylation. The most frequently observed copy number gain affected the chromosomes 8q and 13. Eight adenomas presenting somatic mutations in APC also exhibited distinct global hypomethylation. Previous publications have reported that mutations in APC precede global hypomethylation. Interestingly, one adenoma showed significant hypomethylation but no detectable CNAs or APC mutations. The two SSA samples showed the characteristic BRAF V600E mutations and the FAP sample presented germline mutation in APC. The FAP and the SSA samples did not show hypomethylation or CNAs. Most organoids presented CNAs and somatic mutations similar to their matched tissue even after 2 years in culture. However, few organoids developed new CNAs and somatic variants. Monitoring the changes in organoid may provide important information on tumor progression.

This assay measured CNAs and methylation in colorectal cancer samples, findings which may assist in determining the status of the disease and provide guidance to the appropriate action. Our NGS assay interrogates a significant portion of the genome leading to a more accurate and sensitive evaluation of the state of these cancer cells.

Note: This abstract was not presented at the meeting.

Citation Format: Julie C. Laliberte, Michael K. Dame, Durga Attili, Bodrul Islam, Kevin Kim, Jessica Zhang, Erica L. Katz, Gina M. Newsome, Priya H. Dedhia, Adele Kruger, Tobias Mann, Tom Goodman, Jeffrey Buis, Dean E. Brenner, James Varani, Jason R. Spence, Justin A. Colacino, Jay Stoerker. Simultaneous measurement of global methylation and copy number alterations in human colorectal cancer samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-093. doi:10.1158/1538-7445.AM2017-LB-093

It's worth the wait: optimizing questioning methods for effective intraoperative teaching

BACKGROUND

The use of questioning to engage learners is critical to furthering resident education intraoperatively. Previous studies have demonstrated that higher level questioning and optimal wait times (>3 s) result in learner responses reflective of higher cognition and retention. Given the importance of intraoperative learning, we investigated question delivery in the operating room.

METHODS

A total of 12 laparoscopic cholecystectomies were observed and recorded. All questions were transcribed and classified using Bloom's Taxonomy, a framework associated with hierarchical levels of learning outcomes. Wait time between question end and response was recorded.

RESULTS

Six faculty attendings and seven house officers at our institution were observed. A total of 133 questions were recorded with an average number of questions per case of 11.2. The majority of questions 112 out of 133 (84%) were classified as Bloom's levels 1-3, with only 6% of questions of the highest level. The wait time before the resident answered the question averaged 1.75 s, with attendings interceding after 2.50 s. Question complexity and wait time did not vary based on resident postgraduate year level suggesting limited tailoring of question to learner.

CONCLUSIONS

Intraoperative questioning is not aligned with higher level thinking. The majority of questions were Bloom's level 3 or below, limiting the complexity of answer formulation. Most responses were given within 2 s, hindering opportunity to pursue higher-order thinking. This suggests including higher level questions and tailoring questions to learner level may improve retention and maximize gains. In addition, with attendings answering 20% of their own questions, increasing their wait time offers another area for teaching development.

Notch1 and Notch2 receptors regulate mouse and human gastric antral epithelial cell homoeostasis

OBJECTIVE

We tested the ability of Notch pathway receptors Notch1 and Notch2 to regulate stem and epithelial cell homoeostasis in mouse and human gastric antral tissue.

DESIGN

Mice were treated with the pan-Notch inhibitor dibenzazepine (DBZ) or inhibitory antibodies targeting Notch1 and/or Notch2. Epithelial proliferation, apoptosis and cellular differentiation were measured by histological and molecular approaches. Organoids were established from mouse and human antral glands; growth and differentiation were measured after treatment with Notch inhibitors.

RESULTS

Notch1 and Notch2 are the predominant Notch receptors expressed in mouse and human antral tissue and organoid cultures. Combined inhibition of Notch1 and Notch2 in adult mice led to decreased epithelial cell proliferation, including reduced proliferation of LGR5 stem cells, and increased apoptosis, similar to the response to global Notch inhibition with DBZ. Less pronounced effects were observed after inhibition of individual receptors. Notch pathway inhibition with DBZ or combined inhibition of Notch1 and Notch2 led to increased differentiation of all gastric antral lineages, with remodelling of cells to express secretory products normally associated with other regions of the GI tract, including intestine. Analysis of mouse and human organoids showed that Notch signalling through Notch1 and Notch2 is intrinsic to the epithelium and required for organoid growth.

CONCLUSIONS

Notch signalling is required to maintain gastric antral stem cells. Notch1 and Notch2 are the primary Notch receptors regulating epithelial cell homoeostasis in mouse and human stomach.

Regeneration of fat cells from myofibroblasts during wound healing

Although regeneration through the reprogramming of one cell lineage to another occurs in fish and amphibians, it has not been observed in mammals. We discovered in the mouse that during wound healing, adipocytes regenerate from myofibroblasts, a cell type thought to be differentiated and nonadipogenic. Myofibroblast reprogramming required neogenic hair follicles, which triggered bone morphogenetic protein (BMP) signaling and then activation of adipocyte transcription factors expressed during development. Overexpression of the BMP antagonist Noggin in hair follicles or deletion of the BMP receptor in myofibroblasts prevented adipocyte formation. Adipocytes formed from human keloid fibroblasts either when treated with BMP or when placed with human hair follicles in vitro. Thus, we identify the myofibroblast as a plastic cell type that may be manipulated to treat scars in humans.

In vitro patterning of pluripotent stem cell-derived intestine recapitulates in vivo human development

The intestine plays a central role in digestion, nutrient absorption and metabolism, with individual regions of the intestine having distinct functional roles. Many examples of region-specific gene expression in the adult intestine are known, but how intestinal regional identity is established during development is a largely unresolved issue. Here, we have identified several genes that are expressed in a region-specific manner in the developing human intestine. Using human embryonic stem cell-derived intestinal organoids, we demonstrate that the duration of exposure to active FGF and WNT signaling controls regional identity. Short-term exposure to FGF4 and CHIR99021 (a GSK3β inhibitor that stabilizes β-catenin) resulted in organoids with gene expression patterns similar to developing human duodenum, whereas longer exposure resulted in organoids similar to ileum. When region-specific organoids were transplanted into immunocompromised mice, duodenum-like organoids and ileum-like organoids retained their regional identity, demonstrating that regional identity of organoids is stable after initial patterning occurs. This work provides insights into the mechanisms that control regional specification of the developing human intestine and provides new tools for basic and translational research.

Summary: Human embryonic stem cell-derived intestinal organoids can be patterned into duodenum-like or ileum-like tissue, recapitulating in vivo human development.

Intraoperative questioning to advance higher-order thinking

BACKGROUND

The type of question asked elicits a particular response. The purpose of this study was to determine what types and levels of questions were asked in the operating room. These insights are important for understanding how questions are used to advance learners.

METHODS

12 laparoscopic cholecystectomy operations were observed and recorded at a single institution. Intraoperative questions asked by faculty were transcribed for all cases. Using revised Bloom's taxonomy, questions were classified into one of 5 levels: (1) remembering, (2) understanding, (3) applying, (4) analyzing, (5) evaluating.

RESULTS

141 questions were asked by faculty and ranged from 0 to 34 questions per case. Classification of questions showed there were 43 remembering, 29 understanding, 47 applying, 13 analyzing, and 8 evaluating questions asked.

CONCLUSIONS

Questioning was predominately classified at lower-order and mid-level thinking skills (120/141). Integrating intraoperative questions at higher-order levels has the potential to guide trainees into progressively complex thinking and decision making.

A bioengineered niche promotes in vivo engraftment and maturation of pluripotent stem cell derived human lung organoids

Human pluripotent stem cell (hPSC) derived tissues often remain developmentally immature in vitro, and become more adult-like in their structure, cellular diversity and function following transplantation into immunocompromised mice. Previously we have demonstrated that hPSC-derived human lung organoids (HLOs) resembled human fetal lung tissue in vitro (Dye et al., 2015). Here we show that HLOs required a bioartificial microporous poly(lactide-co-glycolide) (PLG) scaffold niche for successful engraftment, long-term survival, and maturation of lung epithelium in vivo. Analysis of scaffold-grown transplanted tissue showed airway-like tissue with enhanced epithelial structure and organization compared to HLOs grown in vitro. By further comparing in vitro and in vivo grown HLOs with fetal and adult human lung tissue, we found that in vivo transplanted HLOs had improved cellular differentiation of secretory lineages that is reflective of differences between fetal and adult tissue, resulting in airway-like structures that were remarkably similar to the native adult human lung.

Organoid Models of Human Gastrointestinal Development and Disease

We have greatly advanced our ability to grow a diverse range of tissue-derived and pluripotent stem cell-derived gastrointestinal (GI) tissues in vitro. These systems, broadly referred to as organoids, have allowed the field to move away from the often nonphysiological, transformed cell lines that have been used for decades in GI research. Organoids are derived from primary tissues and have the capacity for long-term growth. They contain varying levels of cellular complexity and physiological similarity to native organ systems. We review the latest discoveries from studies of tissue-derived and pluripotent stem cell-derived intestinal, gastric, esophageal, liver, and pancreatic organoids. These studies have provided important insights into GI development, tissue homeostasis, and disease and might be used to develop personalized medicines.

Transcriptome-wide Analysis Reveals Hallmarks of Human Intestine Development and Maturation In Vitro and In Vivo

Human intestinal organoids (HIOs) are a tissue culture model in which small intestine-like tissue is generated from pluripotent stem cells. By carrying out unsupervised hierarchical clustering of RNA-sequencing data, we demonstrate that HIOs most closely resemble human fetal intestine. We observed that genes involved in digestive tract development are enriched in both fetal intestine and HIOs compared to adult tissue, whereas genes related to digestive function and Paneth cell host defense are expressed at higher levels in adult intestine. Our study also revealed that the intestinal stem cell marker OLFM4 is expressed at very low levels in fetal intestine and in HIOs, but is robust in adult crypts. We validated our findings using in vivo transplantation to show that HIOs become more adult-like after transplantation. Our study emphasizes important maturation events that occur in the intestine during human development and demonstrates that HIOs can be used to model fetal-to-adult maturation.

Potential effects of molecular testing of indeterminate thyroid nodule fine needle aspiration biopsy on thyroidectomy volume

BACKGROUND

Increasing utilization of genetic expression profiling (GEP) for thyroid nodules with indeterminate fine needle aspiration (FNA) results will potentially decrease the number of patients requiring diagnostic thyroidectomy. This study sought to determine the potential effects of GEP for indeterminate thyroid FNA results on thyroidectomy volume.

METHODS

A retrospective review of thyroidectomy procedures performed over 1 year at the University of Michigan in the endocrine surgery division evaluated the indications for thyroidectomy, FNA Bethesda classification, and final surgical pathology to determine how application of GEP on indeterminate FNA results would affect decision for surgery and subsequent thyroidectomy volume.

RESULTS

During the study period, 358 thyroidectomies were performed. The indication for procedure included: FNA findings, n = 122; symptomatic multinodular goiter, n = 85; nodule >4 cm, n = 30; Graves', n = 26; other, n = 95. FNA was performed in 231 patients. Bethesda classification included: benign, n = 69; malignant, n = 55; follicular lesion of undetermined significance, n = 59; follicular neoplasm, n = 20; suspicious for malignancy, n = 16; nondiagnostic, n = 12. If standard GEP was performed for all indeterminate FNA results, it would have influenced the decision for surgery in 68 (19 %) patients. Assuming 38 % of indeterminate FNA specimens will have benign results on genetic profiling, 27 patients would not have undergone thyroidectomy, translating into a 7.2 % decrease in overall thyroidectomy volume over a year.

CONCLUSIONS

In an academic endocrine surgery program, the most common indication for thyroidectomy is an FNA result; however, standard application of GEP for all indeterminate thyroid FNAs would result in a minimal reduction in overall thyroidectomy volume.

Transformation by Tribbles homolog 2 (Trib2) requires both the Trib2 kinase domain and COP1 binding

Tribbles homolog 2 (Trib2) is a pseudokinase that induces acute myelogenous leukemia (AML) in mice and is highly expressed in a subset of human AML. Trib2 has 3 distinct regions, a proline-rich N-terminus, a serine/threonine kinase homology domain, and a C-terminal constitutive photomorphogenesis 1 (COP1)-binding domain. We performed a structure-function analysis of Trib2 using in vitro and in vivo assays. The N-terminus was not required for Trib2-induced AML. Deletion or mutation of the COP1-binding site abrogated the ability of Trib2 to degrade CCAAT/enhancer-binding protein-α (C/EBP-α), block granulocytic differentiation, and to induce AML in vivo. Furthermore, COP1 knockdown inhibited the ability of Trib2 to degrade C/EBP-α, showing that it is important for mediating Trib2 activity. We also show that the Trib2 kinase domain is essential for its function. Trib2 contains variant catalytic loop sequences, compared with conventional kinases, that we show are necessary for Trib2 activity. The kinase domain mutants bind, but cannot efficiently degrade, C/EBP-α. Together, our data demonstrate that Trib2 can bind both COP1 and C/EBP-α, leading to degradation of C/EBP-α. Identification of the functional regions of Trib2 that are essential to its oncogenic role provides the basis for developing inhibitors that will block Trib functions in cancer.