α-Mannosylated HLA-II glycopeptide antigens dominate the immunopeptidome of immortalised cells and tumour tissues.

Immunopeptides are cell surface-located protein fragments that aid our immune system to recognise and respond to pathogenic insult and malignant transformation. In this two-part communication, we firstly summarise and reflect on our recent discovery documenting that MHC-II-bound immunopeptides from immortalised cell lines prevalently carry N-glycans that differ from the cellular glycoproteome (Goodson, Front Immunol, 2023), data discussed at the 2023 SfG Annual Meeting. These findings are important as immunopeptide glycosylation remains poorly understood in immunosurveillance. The study also opened up new technical and biological questions that we address in the second part of this communication. Our study highlighted that the performance of the search engines used to detect glycosylated immunopeptides from LC-MS/MS data remains untested and, importantly, that little biochemical in vivo evidence is available to document the nature of glycopeptide antigens in tumour tissues. To this end, we compared the N-glycosylated MHC-II-bound immunopeptides that were reported from tumour tissues of 14 meningioma patients in the MSFragger-HLA-Glyco database (Bedran, Nat Commun, 2023) to those we identified with the commercial Byonic software. Encouragingly, the search engines produced similar outputs supporting that N-glycosylated MHC-II-bound immunopeptides are prevalent in meningioma tumour tissues. Consistent also with in vitro findings, the tissue MHC-II-bound immunopeptides were found to predominantly carry hyper-processed (paucimannosidic- and chitobiose core-type) and hypo-processed (oligomannosidic-type) N-glycans that varied in prevalence and distribution between patients. Taken together, evidence is emerging suggesting that α-mannosidic glycoepitopes abundantly decorate MHC-II-bound immunopeptides in both immortalised cells and tumour tissues warranting further research into their functional roles in immunosurveillance.

Perioperative hypotension and use of vasoactive agents in non-cardiac surgery: A scoping review.

BACKGROUND: Perioperative hypotension is common and associated with adverse patient outcomes. Vasoactive agents are often used to manage hypotension, but the ideal drug, dose and duration of treatment has not been established. With this scoping review, we aim to provide an overview of the current body of evidence regarding the vasoactive agents used to treat perioperative hypotension in non-cardiac surgery. METHODS: We included all studies describing the use of vasoactive agents for the treatment of perioperative hypotension in non-cardiac surgery. We excluded literature reviews, case studies, and studies on animals and healthy subjects. We posed the following research questions: (1) in which surgical populations have vasoactive agents been studied? (2) which agents have been studied? (3) what doses have been assessed? (4) what is the duration of treatment? and (5) which desirable and undesirable outcomes have been assessed? RESULTS: We included 124 studies representing 10 surgical specialties. Eighteen different agents were evaluated, predominantly phenylephrine, ephedrine, and noradrenaline. The agents were administered through six different routes, and numerous comparisons between agents, dosages and routes were included. Then, 88 distinct outcome measures were assessed, of which 54 were judged to be non-patient-centred. CONCLUSIONS: We found that studies concerning vasoactive agents for the treatment of perioperative hypotension varied considerably in all aspects. Populations were heterogeneous, interventions and exposures included multiple agents compared against themselves, each other, fluids or placebo, and studies reported primarily non-patient-centred outcomes.

Comparative Rates of Stroke and Rehospitalization of Atrial Fibrillation in Patients with Perioperative Atrial Fibrillation Following Major Emergency Abdominal Surgery and Patients with Non-perioperative Atrial Fibrillation.

BACKGROUND: Major emergency abdominal surgery is associated with postoperative complications and high mortality. Long-term outcomes in patients with perioperative atrial fibrillation (POAF) have recently received increased attention, especially POAF in non-thoracic surgery. PURPOSE: This study aimed to compare long-term AF related hospitalization and stroke in patients with POAF in relation to major emergency abdominal surgery and in patients with non-perioperative AF. METHODS: We crosslinked data from Danish nationwide registries and identified all patients who underwent major emergency abdominal surgery (2000-2018) and were diagnosed with POAF, and patients who developed AF in a non-perioperative setting. Patients with POAF were matched in a 1:5 ratio on age, sex, year of AF diagnosis and oral anticoagulation (OAC) status at the beginning of follow-up with patients with non-perioperative AF. From discharge, we examined adjusted hazard ratios (HR) of stroke using multivariable Cox regression analysis. RESULTS: The study population comprised 1,041 (out of 42,021 who underwent major emergency abdominal surgery) patients with POAF and 5,205 patients with non-perioperative AF. The median age was 78 years [interquartile range: 71-84] for those initiated on OAC therapy and 78 years [interquartile range: 71-85] for those not initiated on OAC therapy. During the first year of follow up, POAF was associated with similar rates of stroke as non-perioperative AF (patients initiated on OAC: HR 0.96 (95% confidence interval (CI) 0.52-1.77) and patients not initiated on OAC: HR 0.69 (95% CI 0.41-1.15). CONCLUSION: POAF in relation to major emergency abdominal surgery was associated with similar rates of stroke as non-perioperative AF. These results suggest that POAF not only carry an acute burden but also a long-term burden in patients undergoing major emergency abdominal surgery.

Mathematical modelling of stem and progenitor cell dynamics during ruxolitinib treatment of patients with myeloproliferative neoplasms.

Introduction: The Philadelphia chromosome-negative myeloproliferative neoplasms are a group of slowly progressing haematological malignancies primarily characterised by an overproduction of myeloid blood cells. Patients are treated with various drugs, including the JAK1/2 inhibitor ruxolitinib. Mathematical modelling can help propose and test hypotheses of how the treatment works. Materials and methods: We present an extension of the Cancitis model, which describes the development of myeloproliferative neoplasms and their interactions with inflammation, that explicitly models progenitor cells and can account for treatment with ruxolitinib through effects on the malignant stem cell response to cytokine signalling and the death rate of malignant progenitor cells. The model has been fitted to individual patients' data for the JAK2 V617F variant allele frequency from the COMFORT-II and RESPONSE studies for patients who had substantial reductions (20 percentage points or 90% of the baseline value) in their JAK2 V617F variant allele frequency (n = 24 in total). Results: The model fits very well to the patient data with an average root mean square error of 0.0249 (2.49%) when allowing ruxolitinib treatment to affect both malignant stem and progenitor cells. This average root mean square error is much lower than if allowing ruxolitinib treatment to affect only malignant stem or only malignant progenitor cells (average root mean square errors of 0.138 (13.8%) and 0.0874 (8.74%), respectively). Discussion: Systematic simulation studies and fitting of the model to the patient data suggest that an initial reduction of the malignant cell burden followed by a monotonic increase can be recapitulated by the model assuming that ruxolitinib affects only the death rate of malignant progenitor cells. For patients exhibiting a long-term reduction of the malignant cells, the model predicts that ruxolitinib also affects stem cell parameters, such as the malignant stem cells' response to cytokine signalling.

Risk prediction models in emergency surgery: Protocol for a scoping review.

BACKGROUND: Risk prediction models are used for many purposes in emergency surgery, including critical care triage and benchmarking. Several risk prediction models have been developed, and some are used for purposes other than those for which they were developed. We aim to provide an overview of the existing literature on risk prediction models used in emergency surgery and highlight knowledge gaps. METHODS: We will conduct a scoping review on risk prediction models used for patients undergoing emergency surgery in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). We will search Medline, EMBASE, and the Cochrane Library and include all study designs. We aim to answer the following questions: (1) What risk prediction models are used in emergency surgery? (2) Which variables are used in these models? (3) Which surgical specialties are the models used for? (4) Have the models been externally validated? (5) Where have the models been externally validated? (6) What purposes were the models developed for? (7) What are the strengths and limitations of the included models? We will summarize the results descriptively. The certainty of evidence will be evaluated using a modified Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. CONCLUSION: The outlined scoping review will summarize the existing literature on risk prediction models used in emergency surgery and highlight knowledge gaps.

Neutrophil-to-lymphocyte ratio and all-cause mortality with and without myeloproliferative neoplasms-a Danish longitudinal study.

The neutrophil-to-lymphocyte ratio(NLR) is increased in chronic inflammation and myeloproliferative neoplasms (MPN). We hypothesize that NLR is associated with all-cause mortality and mortality by comorbidity burden in the general population and individuals with MPN. We included 835,430 individuals from The Danish General Suburban Population Study, general practitioners, and outpatient clinics. We investigated NLR on mortality stratified by prevalent and incident MPN, essential thrombocythemia (ET), polycythemia vera (PV), myelofibrosis (MF), comorbidity burden (CCI-score), and the Triple-A risk score using hazard ratio (HR) and 95% confidence interval (95%CI). NLR 1-1.9 was the reference level. During a median follow-up of 11.2 years, 197,802 deaths were recorded. All-cause mortality increased for a stepwise increasing NLR with a HR (95%CI) for NLR ≥ 6 of 2.06(2.03-2.09) for the whole population and 2.93(2.44-3.50) in prevalent MPN. ET, PV, and MF had a HR (95%CI) for NLR ≥ 2 of 2.14(1.71-2.69), 2.19(1.89-2.54), and 2.31(1.91-2.80). Results were similar for incident MPN. Mortality was higher for stepwise increasing NLR and CCI-score(pinteraction < 2×10-16), with a HR for NLR ≥ 6 of 2.23(2.17-2.29), 4.10(4.01-4.20), and 7.69(7.50-7.89), for CCI-score 0, 1-2, or ≥3. The Triple-A risk score demonstrated alignment with NLR. Increasing NLR and comorbidity burden were associated with lower survival in individuals without MPN but were even worse in prevalent and incident MPN, ET, PV, and MF.

Profound N-glycan remodelling accompanies MHC-II immunopeptide presentation.

Immunopeptidomics, the study of peptide antigens presented on the cell surface by the major histocompatibility complex (MHC), offers insights into how our immune system recognises self/non-self in health and disease. We recently discovered that hyper-processed (remodelled) N-glycans are dominant features decorating viral spike immunopeptides presented via MHC-class II (MHC-II) molecules by dendritic cells pulsed with SARS-CoV-2 spike protein, but it remains unknown if endogenous immunopeptides also undergo N-glycan remodelling. Taking a multi-omics approach, we here interrogate published MHC-II immunopeptidomics datasets of cultured monocyte-like (THP-1) and breast cancer-derived (MDA-MB-231) cell lines for overlooked N-glycosylated peptide antigens, which we compare to their source proteins in the cellular glycoproteome using proteomics and N-glycomics data from matching cell lines. Hyper-processed chitobiose core and paucimannosidic N-glycans alongside under-processed oligomannosidic N-glycans were found to prevalently modify MHC-II-bound immunopeptides isolated from both THP-1 and MDA-MB-231, while complex/hybrid-type N-glycans were (near-)absent in the immunopeptidome as supported further by new N-glycomics data generated from isolated MHC-II-bound peptides derived from MDA-MB-231 cells. Contrastingly, the cellular proteomics and N-glycomics data from both cell lines revealed conventional N-glycosylation rich in complex/hybrid-type N-glycans, which, together with the identification of key lysosomal glycosidases, suggest that MHC-II peptide antigen processing is accompanied by extensive N-glycan trimming. N-glycan remodelling appeared particularly dramatic for cell surface-located glycoproteins while less remodelling was observed for lysosomal-resident glycoproteins. Collectively, our findings indicate that both under- and hyper-processed N-glycans are prevalent features of endogenous MHC-II immunopeptides, an observation that demands further investigation to enable a better molecular-level understanding of immune surveillance.

Aging, Inflammation, and Comorbidity in Cancers-A General In Silico Study Exemplified by Myeloproliferative Malignancies.

(1) Background: We consider dormant, pre-cancerous states prevented from developing into cancer by the immune system. Inflammatory morbidity may compromise the immune system and cause the pre-cancer to escape into an actual cancerous development. The immune deficiency described is general, but the results may vary across specific cancers due to different variances (2) Methods: We formulate a general conceptual model to perform rigorous in silico consequence analysis. Relevant existing data for myeloproliferative malignancies from the literature are used to calibrate the in silico computations. (3) Results and conclusions: The hypothesis suggests a common physiological origin for many clinical and epidemiological observations in relation to cancers in general. Examples are the observed age-dependent prevalence for hematopoietic cancers, a general mechanism-based explanation for why the risk of cancer increases with age, and how somatic mutations in general, and specifically seen in screenings of citizens, sometimes are non-increased or even decrease when followed over time. The conceptual model is used to characterize different groups of citizens and patients, describing different treatment responses and development scenarios.

Perioperative Atrial Fibrillation and One-year Clinical Outcomes in Patients Following Major Emergency Abdominal Surgery.

The prevalence and impact of perioperative atrial fibrillation (AF) during an admission for major emergency abdominal surgery are sparsely examined. Therefore, this study aimed to compare the 30-day and 1-year outcomes (AF-related hospitalization, stroke, and all-cause mortality) in patients with and without perioperative AF to their major emergency abdominal surgery. All patients without a history of AF who underwent major emergency abdominal surgery from 2000 to 2019 and discharged alive were identified using Danish nationwide registries. Patients with and without perioperative AF (defined as new-onset AF during the index hospitalization) were matched 1:4 on age, gender, year of surgery, and type of surgery. The cumulative incidences and hazard ratios of outcomes were assessed using a multivariable Cox regression analysis comparing patients with and without perioperative AF. A total of 2% of patients were diagnosed with perioperative AF. The matched cohort comprised 792 and 3,168 patients with and without perioperative AF, respectively (median age 78 years [twenty-fifth to seventy-fifth percentile 70 to 83 years]; 43% men). Cumulative incidences of AF-related hospitalizations, stroke, and mortality 1 year after discharge were 30% versus 3.4%, 3.4% versus 2.7%, and 35% versus 22% in patients with and without perioperative AF, respectively. The 30-day outcomes were similarly elevated among patients with perioperative AF. Perioperative AF during an admission for major emergency abdominal surgery was associated with higher 30-day and 1-year rates of AF-related hospitalization and mortality and similar rates of stroke. These findings suggest that perioperative AF is a prognostic marker of increased morbidity and mortality in relation to major emergency abdominal surgery and warrants further investigation.

Therapeutic cancer vaccination against mutant calreticulin in myeloproliferative neoplasms induces expansion of specific T cells in the periphery but specific T cells fail to enrich in the bone marrow.

Background: Therapeutic cancer vaccination against mutant calreticulin (CALR) in patients with CALR-mutant (CALRmut) myeloproliferative neoplasms (MPN) induces strong T-cell responses against mutant CALR yet fails to demonstrate clinical activity. Infiltration of tumor specific T cells into the tumor microenvironment is needed to attain a clinical response to therapeutic cancer vaccination. Aim: Determine if CALRmut specific T cells isolated from vaccinated patients enrich in the bone marrow upon completion of vaccination and explore possible explanations for the lack of enrichment. Methods: CALRmut specific T cells from four of ten vaccinated patients were expanded, enriched, and analyzed by T-cell receptor sequencing (TCRSeq). The TCRs identified were used as fingerprints of CALRmut specific T cells. Bone marrow aspirations from the four patients were acquired at baseline and at the end of trial. T cells were enriched from the bone marrow aspirations and analyzed by TCRSeq to identify the presence and fraction of CALRmut specific T cells at the two different time points. In silico calculations were performed to calculate the ratio between transformed cells and effector cells in patients with CALRmut MPN. Results: The fraction of CALRmut specific T cells in the bone marrow did not increase upon completion of the vaccination trial. In general, the T cell repertoire in the bone marrow remains relatively constant through the vaccination trial. The enriched and expanded CALRmut specific T cells recognize peripheral blood autologous CALRmut cells. In silico analyses demonstrate a high imbalance in the fraction of CALRmut cells and CALRmut specific effector T-cells in peripheral blood. Conclusion: CALRmut specific T cells do not enrich in the bone marrow after therapeutic cancer peptide vaccination against mutant CALR. The specific T cells recognize autologous peripheral blood derived CALRmut cells. In silico analyses demonstrate a high imbalance between the number of transformed cells and CALRmut specific effector T-cells in the periphery. We suggest that the high burden of transformed cells in the periphery compared to the number of effector cells could impact the ability of specific T cells to enrich in the bone marrow.

Comprehensive Glycoprofiling of Oral Tumors Associates N-Glycosylation With Lymph Node Metastasis and Patient Survival.

While altered protein glycosylation is regarded a trait of oral squamous cell carcinoma (OSCC), the heterogeneous and dynamic glycoproteome of tumor tissues from OSCC patients remain unmapped. To this end, we here employ an integrated multi-omics approach comprising unbiased and quantitative glycomics and glycoproteomics applied to a cohort of resected primary tumor tissues from OSCC patients with (n = 19) and without (n = 12) lymph node metastasis. While all tumor tissues displayed relatively uniform N-glycome profiles suggesting overall stable global N-glycosylation during disease progression, altered expression of six sialylated N-glycans was found to correlate with lymph node metastasis. Notably, glycoproteomics and advanced statistical analyses uncovered altered site-specific N-glycosylation revealing previously unknown associations with several clinicopathological features. Importantly, the glycomics and glycoproteomics data unveiled that comparatively high abundance of two core-fucosylated and sialylated N-glycans (Glycan 40a and Glycan 46a) and one N-glycopeptide from fibronectin were associated with low patient survival, while a relatively low abundance of N-glycopeptides from both afamin and CD59 were also associated with poor survival. This study provides insight into the complex OSCC tissue N-glycoproteome, thereby forming an important resource to further explore the underpinning disease mechanisms and uncover new prognostic glycomarkers for OSCC.

Validation of the NELA risk prediction model in emergency abdominal surgery.

Risk prediction models are frequently used to identify high-risk patients undergoing emergency laparotomy. The National Emergency Laparotomy Audit (NELA) developed a risk prediction model specifically for emergency laparotomy patients, which was recently updated. In this study, we validated the updated NELA model in an external population. Furthermore, we compared it with three other risk prediction models: the original NELA model, the Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) model, and the American Society of Anesthesiologists Physical Status (ASA-PS). We included adult patients undergoing emergency laparotomy at Zealand University Hospital, from March 2017 to January 2019, and Herlev Hospital, from November 2017 to January 2020. Variables included in the risk prediction models were collected retrospectively from the electronic patient records. Discrimination of the risk prediction models was evaluated with area under the curve (AUC) statistics, and calibration was assessed with Cox calibration regression. The primary outcome was 30-day mortality. Out of 1226 included patients, 146 patients (11.9%) died within 30 days. AUC (95% confidence interval) for 30-day mortality was 0.85 (0.82-0.88) for the updated NELA model, 0.84 (0.81-0.87) for the original NELA model, 0.81 (0.77-0.84) for the P-POSSUM model, and 0.76 (0.72-0.79) for the ASA-PS model. Calibration showed underestimation of mortality risk for both the updated NELA, original NELA and P-POSSUM models. The updated NELA risk prediction model performs well in this external validation study and may be used in similar settings. However, the model should only be used to discriminate between low- and high-risk patients, and not for prediction of individual risk due to underestimation of mortality.

Case Report: First longitudinal study of a patient with CALR positive clonal hematopoiesis of indeterminate potential developing into pre-fibrotic myelofibrosis.

Initial diagnosis of overt myeloproliferative neoplasms (MPNs) represents the juncture during clonal evolution when symptoms or complications prompt an afflicted individual to seek medical attention. In 30-40% of the MPN subgroups essential thrombocythemia (ET) and myelofibrosis (MF), somatic mutations in the calreticulin gene (CALR) are drivers of the disease resulting in constitutive activation of the thrombopoietin receptor (MPL). In the current study, we describe a healthy CALR mutated individual during a 12 year follow-up from initial identification of CALR clonal hematopoiesis of indeterminate potential (CHIP) to the diagnosis of pre-MF. The pre-diagnostic exponential development dynamics of the malignant clone demonstrated close correlation with the platelet counts, neutrophil-to-lymphocyte (NLR) ratio, and inversely correlated to hemoglobin and erythrocyte counts. Backward extrapolation of the growth rate indicated the potential for discovery of the malignant clone many years prior to presentation of overt disease, opening a window of opportunity for early treatment intervention. We did not find any additional mutations associated with MPNs and the current case report provides novel information regarding the development of a driver mutation and the association with blood cell counts prior to clinical manifestation of symptoms suggesting that pre-diagnostic dynamics may supplement future diagnostic criteria for early diagnosis and intervention in MPN patients.

Collaboration for Evidence-based Practice and Research in Anaesthesia (CEPRA): A consortium initiative for perioperative research.

Evidence in perioperative care is insufficient. There is an urgent need for large perioperative research programmes, including pragmatic randomised trials, testing daily clinical treatments and unanswered question, thereby providing solid evidence for effects of interventions given to a large and growing number of patients undergoing surgery and anaesthesia. This may be achieved through large collaborations. Collaboration for Evidence-based Practice and Research in Anaesthesia (CEPRA) is a novel collaborative research network founded to pursue evidence-based answers to major clinical questions in perioperative medicine. The aims of CEPRA are to (1) improve clinical treatment and outcomes and optimise the use of resources for patients undergoing anaesthesia and perioperative care, and (2) disseminate results and inform caretakers, patients and relatives, and policymakers of evidence-based treatments in anaesthesia and perioperative medicine. CEPRA is inclusive in its concept. We aim to extend our collaboration with all relevant clinical collaborators and patient associations and representatives. Although initiated in Denmark, CEPRA seeks to develop an international network infrastructure, for example, with other Nordic countries. The work of CEPRA will follow the highest methodological standards. The organisation aims to structure and optimise any element of the research collaboration to reduce economic costs and harness benefits from well-functioning research infrastructure. This includes successive continuation of trials, harmonisation of outcomes, and alignment of data management systems. This paper presents the initiation and visions of the CEPRA network. CEPRA aims to be inclusive, patient-focused, methodologically sound, and to optimise all aspects of research logistics. This will translate into faster research conduct, reliable results, and accelerated clinical implementation of results, thereby benefiting millions of patients whilst being cost and labour-saving.

Intra-operative blood transfusion in elderly patients on antithrombotic therapy.

BACKGROUND: Many elderly patients are receiving antithrombotics, which may increase intra-operative blood loss. We aimed to assess whether chronic antithrombotic therapy was associated with intra-operative transfusion of packed red blood cells in patients at least 80 years of age undergoing elective procedures. METHODS: We performed a secondary analysis of the prospective, observational European multicentre study entitled POSE (peri-interventional outcome study in the elderly) including 9497 surgical patients aged 80 years and older in 177 centres from October 2017 to December 2018. In this secondary analysis we included POSE patients who underwent elective procedures and with available data on chronic antithrombotic therapy. The primary outcome was intra-operative transfusion of packed red blood cells and results were analysed using multiple logistic regression model. We adjusted for the following predetermined explanatory variables: Age, sex, body mass index, American Society of Anaesthesiologists Physical Status Classification System, baseline haemoglobin concentration, disseminated cancer, and type and severity of surgery. RESULTS: A total of 7174 patients were included of whom 4073 (56.8%) were on antithrombotic therapy. Among patients on antithrombotic therapy 191 (4.7%) received intra-operative blood transfusion compared with 98 (3.2%) of patients not on chronic antithrombotic therapy (crude odds ratio: 1.51, 95% CI 1.18-1.94). Following multiple logistic regression analysis, the adjusted odds ratio was 0.98; 0.73-1.32. We found that chronic antithrombotic therapy was associated with intra-operative transfusion of packed red blood cells in elderly patients undergoing elective procedures in an unadjusted analysis, but not in a multivariate adjusted model.

A novel integrated biomarker index for the assessment of hematological responses in MPNs during treatment with hydroxyurea and interferon-alpha2.

BACKGROUND: Conventional cytoreductive therapy for patients with chronic Philadelphia-negative myeloproliferative neoplasms (MPNs) includes hydroxyurea (HU), interferon-alpha2 (IFN), and anagrelide. HU is worldwide the most used cytoreductive agent, which lowers elevated blood cell counts within days in the large majority of patients. However, some patients may experience rebound cytosis when HU is reduced due to cytopenia, thereby potentially giving rise to fluctuating cell counts during therapy. Such rapid oscillations may be harmful and potentially elicit thrombosis. Treatment with IFN gradually lowers elevated cell counts within weeks and when the dosage is reduced, the cell counts do not rapidly increase but are sustained within the normal range in the large majority of patients. Conventional hematological response criteria are among others based upon single absolute cell count values and do not take into account the relative decreases toward normal for each cell count. MATERIALS, METHODS & RESULTS: Using serial data from the Danish DALIAH trial, we herein describe a novel integrated biomarker index for the assessment of hematological and molecular (JAK2V617F) responses in patients with MPNs during treatment with IFN or HU. DISCUSSION: This novel tool convincingly displays the superiority of IFN versus HU in normalizing elevated cell counts. Our results need to be validated in larger studies but already now call for studies of the safety and efficacy of combination therapy during the initial treatment of patients with MPNs.

HSC Niche Dynamics in Regeneration, Pre-malignancy, and Cancer: Insights From Mathematical Modeling.

The hematopoietic stem cell (HSC) niche is a crucial driver of regeneration and malignancy. Its interaction with hematopoietic and malignant stem cells is highly complex and direct experimental observations are challenging. We here develop a mathematical model which helps relate processes in the niche to measurable changes of stem and non-stem cell counts. HSC attached to the niche are assumed to be quiescent. After detachment HSC become activated and divide or differentiate. To maintain their stemness, the progeny originating from division must reattach to the niche. We use mouse data from literature to parametrize the model. By combining mathematical analysis and computer simulations, we systematically investigate the impact of stem cell proliferation, differentiation, niche attachment, and detachment on clinically relevant scenarios. These include bone marrow transplantation, clonal competition, and eradication of malignant cells. According to our model, sampling of blood or bulk marrow provides only limited information about cellular interactions in the niche and the clonal composition of the stem cell population. Furthermore, we investigate how interference with processes in the stem cell niche could help to increase the effect of low-dose chemotherapy or to improve the homing of genetically engineered cells.

Rehospitalisations, repeated aortic surgery, and death in initial survivors of surgery for Stanford type A aortic dissection and the significance of age - a nationwide registry-based cohort study.

AIMS: Describe and compare incidences across age groups of rehospitalization, repeated aortic surgery, and death in patients who survived surgery and hospitalization for type A aortic dissection. METHODS AND RESULTS: From Danish nationwide registries, we identified patients hospitalized with Stanford type A aortic dissections (2006-2018). Survivors of hospitalization and surgery on the ascending aorta and/or aortic arch comprised the study population (n = 606, 36 (38.9%) <60 years old (group I), 194 (32.0%) 60-69 years old (group II), and 176 (29.1%) >69 years old (group III)). During the first year, 62.5% were re-hospitalized and 1.4% underwent repeated aortic surgery with no significant differences across age groups (P = 0.68 and P = 0.39, respectively). Further, 5.9% died (group I: 3.0%, group II: 8.3%, group III: 7.4%, P = 0.04). After 10 years, 8.0% had undergone repeated aortic surgery (group I: 11.5%, group II: 8.5%, group III: 1.6%, P = 0.04) and 10.2% (group I), 17.0% (group II), and 22.2% (group III) had died (P = 0.01). Using multivariable Cox regression analysis, we described long-term outcomes comparing age groups. No age differences were found in one-year outcomes, while age > 69 years compared with age < 60 years was associated with a lower rate of repeated aortic surgery [hazard ratio 0.17, 95% confidence interval (CI) 0.04-0.78] and a higher rate of all-cause mortality (hazard ratio 2.44, 95% CI 1.37-4.34) in the 10-year analyses. CONCLUSION: Rehospitalisations in the first year after discharge were common in all age groups, but survival was high. Repeated aortic surgery was significantly more common among younger than older patients.

Use of vasoactive agents in non-cardiac surgery: Protocol for a scoping review.

BACKGROUND: An increasing number of patients undergo surgical procedures worldwide each year, and despite advances in quality and care, morbidity and mortality rates remain high. Perioperative hypotension is a well-described condition, and is associated with adverse outcomes. Both fluids and vasoactive agents are commonly used to treat hypotension, however, whether one vasoactive agent is preferable over another has yet to be explored. METHODS: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) statement, we plan to conduct a scoping review of studies assessing the use of vasoactive agents in patients undergoing non-cardiac surgery. We will provide an overview of indications, agents used and outcomes assessed. We will assess and report the certainty of evidence according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. RESULTS: We will provide descriptive analyses of the included studies accompanied by tabulated results. CONCLUSION: The outlined scoping review will provide a summary of the body of evidence on the use of vasoactive agents in the non-cardiac surgical population.

Soluble CD163: a novel independent prognostic biomarker in patients with metastatic renal cell carcinoma.

The hemoglobin-haptoglobin scavenger receptor CD163 is present in both a membrane-bound form on monocytes and macrophages (mCD163) and a shed soluble circulating form (sCD163). CD163 is a well-described marker of M2-like tumor-associated macrophages, but in patients with metastatic renal cell carcinoma (mRCC), monocyte mCD163 and serum sCD163 levels have not previously been investigated and associated with patient overall survival (OS). Here, we report mCD163 expression on peripheral blood monocytes, as well as sCD163 serum levels, in samples from 89 patients newly diagnosed with mRCC and 20 healthy controls. We found that in mRCC patients, compared to healthy controls, monocyte mCD163 levels were reduced (P < 0.001) whereas serum sCD163 levels were increased (P = 0.004). Moreover, an inverse correlation between mCD163 and sCD163 levels (P = 0.04) was shown. In survival analyses, intermediary levels of monocyte mCD163 were associated with longest OS, compared to both lower and higher mCD163 levels, which were both associated with worse outcomes (P < 0.01). Further, higher levels of sCD163 at diagnosis were associated with poor OS in both univariate (P < 0.001) and multivariate analysis (HR = 1.28; 95%CI 1.09-1.50, P = 0.002). Importantly, stratification by low vs. high sCD163 was able to separate patients with International Metastatic RCC Database Consortium (IMDC) intermediate risk (IMDCINT) into two subgroups with different OS (P = 0.03): IMDCINT-sCD163LOW showed survival similar to IMDCFAV patients, and IMDCINT-sCD163HIGH showed survival similar to IMDCPOOR patients. Thus, baseline sCD163 is a novel independent biomarker of OS in mRCC, and using sCD163 as an add-on biomarker may improve prognostic value for patients in the heterogenous IMDC intermediate group.