Hypoxia-induced SETX links replication stress with the unfolded protein response

Tumour hypoxia is associated with poor patient prognosis and therapy resistance. A unique transcriptional response is initiated by hypoxia which includes the rapid activation of numerous transcription factors in a background of reduced global transcription. Here, we show that the biological response to hypoxia includes the accumulation of R-loops and the induction of the RNA/DNA helicase SETX. In the absence of hypoxia-induced SETX, R-loop levels increase, DNA damage accumulates, and DNA replication rates decrease. Therefore, suggesting that, SETX plays a role in protecting cells from DNA damage induced during transcription in hypoxia. Importantly, we propose that the mechanism of SETX induction in hypoxia is reliant on the PERK/ATF4 arm of the unfolded protein response. These data not only highlight the unique cellular response to hypoxia, which includes both a replication stress-dependent DNA damage response and an unfolded protein response but uncover a novel link between these two distinct pathways.

Remote Monitoring of Heart Transplant Recipients during the COVID-19 Pandemic

Purpose

The COVID-19 pandemic created significant challenges in monitoring heart transplant (HT) recipients for rejection due to efforts to minimize contact with the hospital setting. The aim of this study was to evaluate the safety and efficacy of transitioning HT patients to home phlebotomy and a monitoring protocol based on gene expression profiling (GEP) and donor derived cell free DNA (ddcfDNA).

Methods

A single-center cohort study that prospectively enrolled consecutive HT patients who were transitioned to a remote monitoring protocol employing home phlebotomy and non-invasive surveillance for rejection. Patients were enrolled starting at 2 months post-HT. Positive GEP values were defined as ≥32 (up to 6 months post-HT) and ≥34 (> 6 months post-HT). A positive ddcfDNA score was defined as >0.12%. A positive biopsy was defined as grade ≥1B/1R

Results

246 HT patients were enrolled and followed for a minimum of 3 months. Mean age was 56±14, 71.5% were male, and median time from transplant was 2.7 years. The average distance of patients from the hospital was 25.6 miles. 359 blood tests were drawn for detection of GEP and ddcfDNA and 102 biopsies performed (Figure). Among 32 patients who had negative results on both tests and had a biopsy, 0 had a positive biopsy. Of 25 patients who had positive results on both tests and had a biopsy, 3 (12%) had a positive biopsy. The biopsy positivity rate in patients who were GEP+/ddcfDNA- was 6% and in patients who were GEP-/ddcfDNA+ was 8%. None of the positive biopsies were associated with hemodynamic compromise. 15 (6%) of patients were admitted due to allograft rejection during the study period. There were no deaths.

Conclusion

Using a remote monitoring protocol with home phlebotomy and noninvasive rejection surveillance was feasible and safe in HT recipients. In this cohort, the combination of negative GEP and ddcfDNA scores was accurate at predicting a lack of allograft rejection.

A14 WIDE VARIATION IN CLINICAL MANAGEMENT OF PAEDIATRIC EOSINOPHILIC ESOPHAGITIS: A CANADIAN EXPERIENCE

Background

Eosinophilic esophagitis (EoE) is a chronic disorder treated by food elimination diet (FED), topical steroids and/or proton-pump inhibitors (PPI). Serial endoscopies and biopsies assess response to therapy. EoE management has evolved as guidelines are updated.

Aims

To identify practice variation among Canadian paediatric gastroenterologists (PG) who care for children with EoE.

Methods

An online survey using REDCap about decision-making in children with EoE was distributed to PG in Canada in November 2020.

Results

62 PG completed the survey (response rate 69%, 62/94). The majority work in academic centres (92%). 3 centers indicated an accrual of >50 new patients per year; 9/16 centres have >100 patients in follow-up. An EoE Clinic is present in 5 centres.

Diagnosis: Familiarity with the 2018 AGREE and 2020 AGA EoE guidelines was found to be 57% and 67% respectively. Criteria required to diagnose EoE according to current guidelines were correctly indicated by 42% of PG. (Figure 1).

Endoscopy: The majority of PG (95%) adhere to guidelines in terms of required number and location of biopsies for the initial diagnosis. Ideal timing of repeat endoscopy after change in therapy in patients who are not in histological remission was 8–12 weeks by 67% of PG, timing in stable patients on maintenance therapy varied (33% only if patient is symptomatic). 25% used the EREFS Score in reporting endoscopic findings.

Therapy: Improvement of symptoms was the highest ranked goal (64%), followed by remission of histologic findings (30%). A treatment algorithm was in place in 4 centers. The majority routinely assess adherence to therapy (73%) and consult a dietitian for FED (77%). Most (87%) do not consult an allergist for initial management. Preferred choices of 1st-line therapy varied among PG (Figure 2). When FED was selected, 32% of PG started with 1 food, 32% started with 2 foods, most frequently excluding dairy, followed by wheat. 14 (26%) start with ≥6 FED. Prescription of budesonide slurry was consistent among PG with doses of 1 and 2 mg/day in children <10 and >10 years, respectively.

Conclusions

The is the first Canadian study to assess the variation in management of children with EoE by PG. Overall, PG demonstrated good adherence to the guidelines in terms of initial diagnosis, but differences in maintenance therapy choice and timing of endoscopies. The results highlight a need for standardized management algorithms to deliver uniform care to this growing group. Grounding these guidelines in evidence will warrant a significant investment in further paediatric EoE research.

Funding Agencies

None

Occupational bladder cancer: A cross section survey of previous employments, tasks and exposures matched to cancer phenotypes

Objectives

Up to 10% of Bladder Cancers may arise following occupational exposure to carcinogens. We hypothesised that different cancer phenotypes reflected different patterns of occupational exposure.

Methods

Consecutive participants, with bladder cancer, self-completed a structured questionnaire detailing employment, tasks, exposures, smoking, lifestyle and family history. Our primary outcome was association between cancer phenotype and occupational details.

Results

We collected questionnaires from 536 patients, of whom 454 (85%) participants (352 men and 102 women) were included. Women were less likely to be smokers (68% vs. 81% Chi sq. p<0.001), but more likely than men to inhale environmental tobacco smoke at home (82% vs. 74% p = 0.08) and use hair dye (56% vs. 3%, p<0.001). Contact with potential carcinogens occurred in 282 (62%) participants (mean 3.1 per worker (range 0–14)). High-grade cancer was more common than low-grade disease in workers from the steel, foundry, metal, engineering and transport industries (p<0.05), and in workers exposed to crack detection dyes, chromium, coal/oil/gas by-products, diesel fumes/fuel/aircraft fuel and solvents (such as trichloroethylene). Higher staged cancers were frequent in workers exposed to Chromium, coal products and diesel exhaust fumes/fuel (p<0.05). Various workers (e.g. exposed to diesel fuels or fumes (Cox, HR 1.97 (95% CI 1.31–2.98) p = 0.001), employed in a garage (HR 2.19 (95% CI 1.31–3.63) p = 0.001), undertaking plumbing/gas fitting/ventilation (HR 2.15 (95% CI 1.15–4.01) p = 0.017), undertaking welding (HR 1.85 (95% CI 1.24–2.77) p = 0.003) and exposed to welding materials (HR 1.92 (95% CI 1.27–2.91) p = 0.002)) were more likely to have disease progression and receive radical treatment than others. Fewer than expected deaths were seen in healthcare workers (HR 0.17 (95% CI 0.04–0.70) p = 0.014).

Conclusions

We identified multiple occupational tasks and contacts associated with bladder cancer. There were some associations with phenotype, although our study design precludes robust assessment.

Nomogram Predicting Bladder Cancer-specific Mortality After Neoadjuvant Chemotherapy and Radical Cystectomy for Muscle-invasive Bladder Cancer: Results of an International Consortium

BACKGROUND

Cisplatin-based neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (MIBC) is associated with improved overall and cancer-specific survival. The post-NAC pathological stage has previously been reported to be a major determinant of outcome.

OBJECTIVE

To develop a postoperative nomogram for survival based on pathological and clinical parameters from an international consortium.

DESIGN, SETTING, AND PARTICIPANTS

Between 2000 and 2015, 1866 patients with MIBC were treated at 19 institutions in the USA, Canada, and Europe. Analysis was limited to 640 patients with adequate follow-up who had received three or more cycles of NAC.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

A nomogram for bladder cancer-specific mortality (BCSM) was developed by multivariable Cox regression analysis. Decision curve analysis was used to assess the model's clinical utility.

RESULTS AND LIMITATIONS

A total of 640 patients were identified. Downstaging to non-MIBC (ypT1, ypTa, and ypTis) occurred in 271 patients (42 %), and 113 (17 %) achieved a complete response (ypT0N0). The 5-yr BCSM was 47.2 % (95 % confidence interval [CI]: 41.2-52.6 %). On multivariable analysis, covariates with a statistically significant association with BCSM were lymph node metastasis (hazard ratio [HR] 1.90 [95% CI: 1.4-2.6]; p < 0.001), positive surgical margins (HR 2.01 [95 % CI: 1.3-2.9]; p < 0.001), and pathological stage (with ypT0/Tis/Ta/T1 as reference: ypT2 [HR 2.77 {95 % CI: 1.7-4.6}; p < 0.001] and ypT3-4 [HR 5.9 {95 % CI: 3.8-9.3}; p < 0.001]). The area under the curve of the model predicting 5-yr BCSM after cross validation with 300 bootstraps was 75.4 % (95 % CI: 68.1-82.6 %). Decision curve analyses showed a modest net benefit for the use of the BCSM nomogram in the current cohort compared with the use of American Joint Committee on Cancer staging alone. Limitations include the retrospective study design and the lack of central pathology.

CONCLUSIONS

We have developed and internally validated a nomogram predicting BCSM after NAC and radical cystectomy for MIBC. The nomogram will be useful for patient counseling and in the identification of patients at high risk for BCSM suitable for enrollment in clinical trials of adjuvant therapy.

PATIENT SUMMARY

In this report, we looked at the outcomes of patients with muscle-invasive bladder cancer in a large multi-institutional population. We found that we can accurately predict death after radical surgical treatment in patients treated with chemotherapy before surgery. We conclude that the pathological report provides key factors for determining survival probability.

Determination of Lead in Wine by Graphite Furnace Atomic Absorption Spectrophotometry: Interlaboratory Study

An interlaboratory study of a graphite furnace atomic absorption spectrophotometry (GFAAS) method for the determination of lead in wine was conducted. Seventeen laboratories from France, United States, and the United Kingdom, using a variety of GFAAS instruments, took part in the study. The method incorporated a novel matrix-matching procedure to minimize matrix effects between standards and samples. Six wine test materials were prepared and sent to participants as 12 blind duplicate or split level samples. There was good agreement between results obtained from participants and target values (24–279 μg/L) obtained with an inductively coupled plasma-mass spectrometry method. The precision of the GFAAS method was well within the range predicted by the Horwitz equation for the 6 test materials analyzed. Repeatability standard deviations ranged from 3 to 17%. Reproducibility standard deviations were in the range of 10 to 30%. The method is recommended for use for official purposes.

Digital pathology for intraoperative frozen section diagnosis of thoracic specimens: an evaluation of a system using remote sampling and whole slide imaging diagnosis

BACKGROUND

Digital pathology is now used for primary diagnostic work as well as teaching, research and consultation. In our multisite institution service reorganisation led to histopathology being located in a separate hospital from some surgical specialities. We implemented remotely supervised specimen sampling and frozen section diagnosis using digital pathology. In this study we assessed the concordance of glass and digital slide diagnosis using this system.

METHODS

We reviewed cases from the first 2 years of digital frozen section reporting at our institution. Cases with potential digital to glass slide discordance were reviewed by three experienced thoracic histopathologists. The reasons for discordance were determined and common themes identified. We also reviewed critical incidents relating to digital pathology during the study period.

RESULTS

The study population comprised 211 cases. Frozen section to final diagnosis concordance between digital and glass slide diagnosis was found in 196 (92.6%) cases. The 15 potentially discordant cases were reviewed. Intraobserver concordance between glass and digital slide review ranged from 9/15 to 12/15 cases across the three pathologists. Glass slide review diagnosis showed better concordance with ground truth in two cases; digital slide review was more accurate in two cases. One relevant critical incident was identified during the study period.

DISCUSSION

This is the largest study to examine digital pathology for thoracic frozen section diagnosis and shows that this is a safe and feasible alternative to glass slide diagnosis. Discordance between digital and glass slide diagnoses were unrelated to the processes of whole slide imaging and digital microscopy.

Evaluation of the Assurance GDS® for Salmonella Method in Foods and Environmental Surfaces: Multilaboratory Collaborative Study

A multilaboratory collaborative study was conducted to compare the detection of Salmonella by the Assurance GDS® for Salmonella method and the Reference culture methods. Six foods, representing a variety of low microbial and high microbial load foods were analyzed. Seventeen laboratories in the United States and Canada participated in this study. No statistical differences (P &lt; 0.05) were observed between the Assurance GDS for Salmonella and the Reference culture methods for any inoculation level of any food type or naturally contaminated food, except for pasta, for which the Assurance GDS method had a higher number of confirmed test portions for Salmonella compared to the Reference method.

Liquid Chromatographic Method for the Quantification of Zearalenone in Baby Food and Animal Feed: Interlaboratory Study

An interlaboratory trial for determination of zearalenone (ZON) in baby food and animal feed was conducted. The study involved 39 participants in 16 European Union member states, as well as Turkey, Uruguay, and China, representing a cross-section of industry, and official food control and research institutes. The method is based on immunoaffinity column cleanup followed by high-performance liquid chromatography using fluorimetry (HPLC-Fl). The test portion of the sample is extracted with methanolwater (75 + 25, v/v). The sample extract is filtered, diluted, and passed over an immunoaffinity column. ZON is eluted with methanol. The separation and determination of ZON is performed by reversed-phase HPLC-Fl with an excitation wavelength of 274 nm and an emission wavelength of 446 nm. Test portions of the samples were spiked at levels of 20 and 30 g/kg ZON in baby food and at levels of 100 and 150 g/kg ZON in animal feed. Mean recoveries from each participant ranged from 78 to 119 with an average value of 92 for baby food and from 51 to 122 with an average value of 74 for animal feed. Based on results for spiked samples (blind duplicates at 2 levels), as well as naturally contaminated samples (blind duplicates at 3 levels), the relative standard deviation for repeatability (RSDr) in baby food ranged from 2.8 to 9.0. For animal feed, this value ranged from 5.7 to 9.5. The relative standard deviation for reproducibility (RSDR) in baby food ranged from 8.2 to 13.3, and for animal feed this value ranged from 15.5 to 21.4. The Horwitz ratio (HorRat) in baby food ranged from 0.3 to 0.4, and for animal feed this value ranged from 0.6 to 0.9. The method showed acceptable within-and between-laboratory precision for each matrix, as required by European legislation.

Determination of Zearalenone in Barley, Maize and Wheat Flour, Polenta, and Maize-Based Baby Food by Immunoaffinity Column Cleanup with Liquid Chromatography: Interlaboratory Study

An interlaboratory study was performed on behalf of the UK Food Standards Agency to evaluate the effectiveness of an affinity column cleanup liquid chromatography (LC) method for the determination of zearalenone (ZON) in a variety of cereals and cereal products at proposed European regulatory limits. The test portion is extracted with acetonitrile:water. The sample extract is filtered, diluted, and applied to an affinity column. The column is washed, and ZON is eluted with acetonitrile. ZON is quantified by reversed-phase LC with fluorescence detection. Barley, wheat and maize flours, polenta, and a maize-based baby food naturally contaminated, spiked, and blank (very low level) were sent to 28 collaborators in 9 European countries and 1 collaborator in New Zealand. Participants were asked to spike test portions of all samples at a ZON concentration equivalent to 100 μg/kg. Average recoveries ranged from 91–111%. Based on results for 4 artificially contaminated samples (blind duplicates) and 1 naturally contaminated sample (blind duplicate), the relative standard deviation for repeatability (RSDr) ranged from 6.9–35.8%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.4–38.2%. The method showed acceptable within- and between-laboratory precision for all 5 matrixes, as evidenced by HorRat values &lt;1.7.

Determination of Ochratoxin A in Currants, Raisins, Sultanas, Mixed Dried Fruit, and Dried Figs by Immunoaffinity Column Cleanup with Liquid Chromatography: Interlaboratory Study

An interlaboratory study was performed on behalf of the Food Standards Agency to evaluate the effectiveness of an affinity column cleanup liquid chromatographic (LC) method for the determination of ochratoxin A in a variety of dried fruit at European regulatory limits. To ensure homogeneity before analysis, laboratory samples are normally slurried with water in the ratio of 5 parts fruit to 4 parts water, and test materials in this form were used in the study. The test portion was extracted with acidified methanol. The extract was filtered, diluted with phosphate-buffered saline, and applied to an affinity column. The column was washed and ochratoxin A was eluted with methanol. Ochratoxin A was quantified by reversed-phase LC. The use of post-column pH shift to enhance the fluorescence of ochratoxin A by the addition of 1.1M ammonia solution to the column eluant is optional. Determination was by fluorescence. Currants, sultanas, raisins, figs, and mixed fruit (comprising dried pineapple, papaya, sultanas, prunes, dates, and banana chips), both naturally contaminated and blank (very low level), were sent to 24 collaborators in 7 European countries. Participants were asked to spike test portions of all test samples at a level equivalent to 5 ng/g ochra toxin A. Average recoveries ranged from 69 to 74%. Based on results for 5 naturally contaminated test samples (blind duplicates) the relative standard deviation for repeatability (RSDr) ranged from 4.9 to 8.7%, and the relative standard deviation for reproducibility (RSDR)rangedfrom14to28%. The method showed acceptable within-and be-tween-laboratory precision for all 5 matrixes, as evidenced by HORRAT values &lt;1.3.