Cancer Metastasis-on-a-Chip for Modeling Metastatic Cascade and Drug Screening

Microfluidic chips are valuable tools for studying intricate cellular and cell-microenvironment interactions. Traditional in vitro cancer models lack accuracy in mimicking the complexities of in vivo tumor microenvironment. However, cancer-metastasis-on-a-chip (CMoC) models combine the advantages of 3D cultures and microfluidic technology, serving as powerful platforms for exploring cancer mechanisms and facilitating drug screening. These chips are able to compartmentalize the metastatic cascade, deepening the understanding of its underlying mechanisms. This article provides an overview of current CMoC models, focusing on distinctive models that simulate invasion, intravasation, circulation, extravasation, and colonization, and their applications in drug screening. Furthermore, challenges faced by CMoC and microfluidic technologies are discussed, while exploring promising future directions in cancer research. The ongoing development and integration of these models into cancer studies are expected to drive transformative advancements in the field.

EGS P01 The diurnal and seasonal relationships of pedestrian injuries secondary to motor vehicles in young people

Background

There remains a significant morbidity and mortality in young pedestrians hit by motor vehicles, even in the era of pedestrian crossings and speed limits. The aim of this study was to compare incidence and injury severity of motor vehicle-related pedestrian trauma according to time of day and season in a young population, based on the supposition that injuries would be more prevalent during dusk and dawn and during autumn and winter.

Methods

Data was retrieved for patients between 10–25 years old from the national Trauma Audit and Research Network (TARN) database, who had been involved as pedestrians in motor vehicle accidents between 2015–2020. The incidence of injuries, their severity (using the Injury Severity Score [ISS]), hospital transfer time and mortality were analysed according to the hours of daylight, darkness and season.

Results

The study identified a seasonal pattern, showing that autumn was the predominant season and lead to 34.9% of injuries, with a further 25.4% in winter in comparison to spring and summer, with 21.4% and 18.3% of injuries respectively. However, visibility alone was not a sufficient factor as 49.5% of injuries occurred during time of darkness, while 50.5% occurred during daylight. Importantly, the greatest injury rate (number of injuries/hour) occurred between 1500–1630 correlating to school pick up times. A further significant relationship between injury severity score (ISS) and daylight was demonstrated (p-value= 0.0124) with moderate injuries (ISS 9–14) occurring most commonly during the day (72.7%) and more severe injuries (ISS>15) occurred during the night (55.8%).

Conclusions

We have identified a relationship between time of day and the frequency and severity of pedestrian trauma in young people. In addition, particular time groupings correspond to the greatest injury rate, suggesting that reduced visibility coupled with school pick up times may play a significant role . This could be addressed through a targeted public health approach to implement change. We recommend targeted public health measures to improve road safety that focus on these times and that increase the visibility of children combined with education for drivers.

Sustainable financing for Immunization Agenda 2030

Sustainable financing for immunization refers to the sufficient and predictable allocation and use of resources to support the achievement of immunization goals within the framework of overall health financing. The Immunization Agenda 2030 (IA2030) agenda spells out four important focus areas needed for sustainable financing: (1) ensuring sufficient and predictable resources, (2) making optimal use of resources, (3) aligning partnerships, and (4) supporting sustainable transitions from external assistance. This paper summarizes the evidence and proposes interventions under each area. While immunization is one of the best investments and justifies public financing, the COVID-19 pandemic has led to the worst economic recession since the Great Depression and threatens countries' ability to mobilize funding to ensure continuity and access to essential services, including immunization. Strategies for ensuring adequate resources differ by income group but include raising more revenues, reprioritizing the budget towards health, and ensuring that health resources favor Primary Health Care (PHC) and immunization. In low- and lower-middle income countries, support from Gavi, the Vaccine Alliance, which channels the largest amount of external financing, will remain important, but some lower-middle income countries will need to prepare for transition. Countries benefitting from the Global Polio Eradication Initiative (GPEI) are also experiencing a transition from GPEI financing to domestic and other external financing. This paper outlines ways in which countries can improve the use of domestic and external resources to better incentivize high-quality PHC and immunization services and align immunization programs with health sector reforms. While governments must lead, collective action from development partners, the private sector, and civil society is needed to promote health system financing systems that ensure that the world is better prepared for future outbreaks and pandemics, while reinforcing the IA2030 vision and making progress towards universal health coverage and the Sustainable Development Goals.

Better Understanding of the Metamorphosis of Pregnancy (BUMP): protocol for a digital feasibility study in women from preconception to postpartum

The Better Understanding the Metamorphosis of Pregnancy (BUMP) study is a longitudinal feasibility study aimed to gain a deeper understanding of the pre-pregnancy and pregnancy symptom experience using digital tools. The present paper describes the protocol for the BUMP study. Over 1000 participants are being recruited through a patient provider-platform and through other channels in the United States (US). Participants in a preconception cohort (BUMP-C) are followed for 6 months, or until conception, while participants in a pregnancy cohort (BUMP) are followed into their fourth trimester. Participants are provided with a smart ring, a smartwatch (BUMP only), and a smart scale (BUMP only) alongside cohort-specific study apps. Participant centric engagement strategies are used that aim to co-design the digital approach with participants while providing knowledge and support. The BUMP study is intended to lay the foundational work for a larger study to determine whether participant co-designed digital tools can be used to detect, track and return multimodal symptoms during the perinatal window to inform individual level symptom trajectories.

Impact of enhanced personal protective equipment on surgeon workload and intraoperative patient outcomes

This work shows the need for targeted improvement to mitigate communication challenges associated with use of enhanced personal protective equipment. The data provide reassurance to surgeons and patients that there is no negative impact on surgeon workload or patient outcomes from use of enhanced personal protective equipment in the operating theatre.

O35 The impact of COVID-19 on access and availability of radiological imaging and surgical intervention at the east Midlands major trauma centre: an icon trauma study

Introduction

During the COVID-19 pandemic, Major Trauma services were subject to significant challenges including reduced access to Computed Tomography (CT) scanning and restrictions on operative intervention due to limited intensive care beds. This study evaluated the pandemic’s impact on access and timeliness of imaging and surgical intervention.

Method

This observational study compared 2 cohorts of patients admitted in a 10-week period during the COVID-19 pandemic and a similar time period in 2019. Variables included demographics, time to CT scan and to surgery and operative characteristics. Statistical comparisons were undertaken using Mann Whitney U, Fisher’s exact and Chi-squared tests.

Result

Of 642 patients, 405 were admitted in 2019 and 237 in 2020 representing a 41.5% absolute reduction in trauma admissions during the pandemic. There were no statistical differences (P = 0.2585) between arrival to the Emergency Department and time to CT scan across both years (median 42 minutes) or between operative approach (P = 0.728) and level of post-operative care (P = 0.788). However, there were statistical differences in time to surgery (P = 0.0193) and operative length (P = 0.0141) with a 2-fold increase in overnight operating, 31.2% increase in patients operated on < 24 hours from admission, and 42.9% reduction in surgery lasting >120 minutes during the COVID-19 pandemic.

Conclusion

Early robust restructuring of trauma services during the COVID-19 pandemic ensured timely access to appropriate imaging and surgery for major trauma injured patients. The higher rates of overnight surgery and shorter duration of procedure were likely explained by the increased onsite availability of suitably trained trauma surgical teams.

Take-home Message

COVID-19 had the potential to significantly impact Major Trauma services, however excellence in patient care was maintained by quick restructuring to staff, space and services Improvements to the Major Trauma pathway have become ingrained into daily practice and optimised for future outbreaks.

617 Does Wearing Enhanced Personal Protective Equipment (PPE) In Theatre Increase Surgeon Workload and Patient Morbidity?

Introduction

Delivery of surgical services during the Covid-19 pandemic has required the use of enhanced PPE in the operating theatre. We sought to evaluate the impact of this change on surgeon workload and intraoperative patient outcomes.

Method

Surgeons performing as primary operator completed an online procedure-specific questionnaire on workload ratings for each operative case, using an extension of the validated Surgeon Task Load Index (SURG-TLX) tool (reported on a 20-point scale), together with operative details. Local approval was obtained at individual sites. Data was analysed in Stata SE v16.

Results

118 responses (17 surgeons, 7 specialties) were collected from June to September 2020. 77.1% used enhanced PPE. There was no association between enhanced PPE use and overall workload (p = 0.151) as measured with SURG-TLX, although surgeons wearing enhanced PPE commonly reported finding individual procedures harder than expected (37% vs 0%, p < 0.001). Communication was rated worse when using enhanced PPE use (MD -4.38, 95%CI -6.74 to 02.03; p < 0.001). There was no association between enhanced PPE use and intraoperative complications (p = 0.745).

Conclusions

The use of enhanced PPE is not associated with complications or increased surgeon workload assessed by SURG-TLX. It is, however, associated with difficulty in communicating, and subjectively experiencing more procedural challenge than anticipated.

664 The ICON Trauma Study: The Impact of the COVID-19 Lockdown on Major Trauma Workload in the UK

Introduction

Anecdotal evidence suggest a direct impact of the SARS-COV-2-pandemic on presentation and severity of major trauma.

Method

This observational study from a UK Major Trauma Centre matched a cohort of patients admitted during a 10-week period of the SARS-CoV-2-pandemic (09/03/2020 to 18/05/2020) to a historical cohort admitted during a similar time period in 2019 (11/03/2019 to 20/05/2019). Demographic differences, injury method and severity were compared using Fisher’s and Chi-squared tests. Multivariable logistic regression examined the associated factors predicting 30-day mortality.

Results

Of 642 patients, 405 and 237 were in the 2019 and 2020 cohorts respectively. 1.69%(4/237) of the 2020 cohort tested SARS-CoV-2 positive. There was a 41.5% decrease in trauma admissions in 2020. The 2020 cohort was older (median 46 vs.40 years), more comorbid and frailer (p < 0.0015). There was a significant difference in injury method with a decrease in vehicle related trauma, but an increase in falls. There was a 2-fold increased risk of mortality in the 2020 cohort that in adjusted models, was explained by higher injury severity and frailty. Positive SARS-CoV-2 status was not associated with increased mortality on multivariable analysis.

Conclusions

Patients admitted during the SARS-CoV-2-pandemic were older, frailer, more co-morbid and had an increased risk of mortality.

1002 Calcium administration in Major haemorrhage Protocol

Introduction

Calcium gluconate is an essential part of the major haemorrhage protocol (MHP). It minimizes the exacerbation of transfusion coagulopathies due to the citrate preservative. As fifty percent of trauma patients present with hypocalcaemia prior to transfusion, the risk is pertinent. Given the importance of the issue, surprisingly current guidelines remain sparse. We analysed the percentage of patients who received calcium and their hypocalcaemia incidence.

Method

A Retrospective review of red traumas during June to August 2019. The frequency of MHP and the patient’s ionised plasma calcium levels on VBG (1.15-1.26mmol/L) were identified. Our standard stated 100% of MHP should receive calcium. A massive transfusion was defined as 10 red blood cells units in 24 hours or 4 blood products within 30mins.

Results

27 red traumas were accepted to audit, MHP was activated in 85%. Out of these 75% received calcium and on average after 6.4 units of blood products. The incidence of ionised hypocalcaemia in all MHP patients was 67%.

Conclusions

We identified a standard that supplementary calcium should be supplemented in all MHPs. Hypocalcaemia was more frequency than our research stipulated. Improvement needs to be made to meet standards. We recommend incorporation of Calcium gluconate into major haemorrhage pack and transfusion guidelines.

Liver organoid as a 3D in vitro model for drug validation and toxicity assessment

The past decade has seen many advancements in the development of three-dimensional (3D) in vitro models in pharmaceutical sciences and industry. Specifically, organoids present a self-organising, self-renewing and more physiologically relevant model than conventional two-dimensional (2D) cell cultures. Liver organoids have been developed from a variety of cell sources, including stem cells, cell lines and primary cells. They have potential for modelling patient-specific disease and establishing personalised therapeutic approaches. Additionally, liver organoids have been used to test drug efficacy and toxicity. Herein we summarise cell sources for generating liver organoids, the advantages and limitations of each cell type, as well as the application of the organoids in modelling liver diseases. We focus on the use of liver organoids as tools for drug validation and toxicity assessment.

Sediment and nutrient sources and sinks in a wet-dry tropical catchment draining to the Great Barrier Reef

Many tropical river systems have altered water quality due to human land use, impacting the biodiversity of freshwater and coastal ecosystems. Long-term, catchment-scale monitoring is needed to understand pollutant sources, controls, and trends. This 12-year study monitored baseflow and flood event nutrient and sediment concentrations, and estimated sediment loads across the Normanby Basin in northern Australia. Suspended sediment concentrations and yields were highest in upper catchment areas where cattle grazing occurred on erosion-prone sodic soils. Mid- and lower catchment rivers and floodplains were a sink for sediments and nutrients, trapping around 75% of suspended sediments during events. Clays (<4 μm) were preferentially transported to the estuary, with an estimated 46% sediment delivery ratio. In the estuary, suspended sediment concentrations were influenced by tidal resuspension processes and there were significant sources of DIN. These findings can help prioritise land management investments for the protection of Great Barrier Reef and freshwater ecosystems.

Maxillofacial injury related to an exploding e-cigarette

Electronic cigarettes (also known as e-cigarettes or electronic nicotine delivery systems) were invented in China in 2003 then introduced to the British market in 2007. They remain popular among the public and are deemed to be effective in reducing tobacco smoking (the UK being one of the first countries to embrace them in a harm reduction policy). However, reports in the media of e-cigarettes exploding are of concern, considering the potential functional and psychological impairment that lifelong disfigurement will cause, especially given their uptake among people of any age. We present a case of this rare, but dramatic, effect of e-cigarette use as a warning to the public.

Viscoelastic haemostatic assay augmented protocols for major trauma haemorrhage (ITACTIC): a randomized, controlled trial

PURPOSE

Contemporary trauma resuscitation prioritizes control of bleeding and uses major haemorrhage protocols (MHPs) to prevent and treat coagulopathy. We aimed to determine whether augmenting MHPs with Viscoelastic Haemostatic Assays (VHA) would improve outcomes compared to Conventional Coagulation Tests (CCTs).

METHODS

This was a multi-centre, randomized controlled trial comparing outcomes in trauma patients who received empiric MHPs, augmented by either VHA or CCT-guided interventions. Primary outcome was the proportion of subjects who, at 24 h after injury, were alive and free of massive transfusion (10 or more red cell transfusions). Secondary outcomes included 28-day mortality. Pre-specified subgroups included patients with severe traumatic brain injury (TBI).

RESULTS

Of 396 patients in the intention to treat analysis, 201 were allocated to VHA and 195 to CCT-guided therapy. At 24 h, there was no difference in the proportion of patients who were alive and free of massive transfusion (VHA: 67%, CCT: 64%, OR 1.15, 95% CI 0.76-1.73). 28-day mortality was not different overall (VHA: 25%, CCT: 28%, OR 0.84, 95% CI 0.54-1.31), nor were there differences in other secondary outcomes or serious adverse events. In pre-specified subgroups, there were no differences in primary outcomes. In the pre-specified subgroup of 74 patients with TBI, 64% were alive and free of massive transfusion at 24 h compared to 46% in the CCT arm (OR 2.12, 95% CI 0.84-5.34).

CONCLUSION

There was no difference in overall outcomes between VHA- and CCT-augmented-major haemorrhage protocols.

Effect of metabolic syndrome components on the risk of malignancy in patients with gallbladder lesions

Background: Gallbladder lesions have become more common nowadays. But there is limited evidence-based guidance on surveillance of these patients for malignancy. Predicting malignancy could help clinicians better manage this condition and improve the prognosis. We evaluated the independent and joint effects of metabolic syndrome components on the risk of malignancy among patients with gallbladder lesions.

Methods: Using a multicenter database, consecutive patients with pathologically confirmed gallbladder lesions between 2012 and 2019 were identified. Univariate and multivariate logistic regression analyses were used to evaluate the effects of metabolic syndrome components (diabetes, hypertension, dyslipidemia and obesity) as additive or combined indicators for the risk of malignancy. Unadjusted and adjusted odds ratios were calculated.

Results: Of the 625 patients, 567 patients were identified with benign gallbladder lesions and 58 patients with gallbladder cancer (GBC). GBC group had less obesity but more dyslipidemia. Among all metabolic syndrome components, only dyslipidemia was significantly associated with GBC (odds ratio 2.674, 95% confidence interval 1.173-6.094). Dyslipidemia was an independent risk factor for malignancy (adjusted odds ratio 2.164, 95% confidence interval 1.165-4.021), regardless of whether the other risk factors and metabolic syndrome components were combined. Patients with decreased high-density lipoprotein had 3.035-fold higher risk of malignancy (adjusted odds ratio 3.035, 95% confidence interval 1.645-5.600).

Conclusions: Dyslipidemia is associated with a 2.674-fold increase in the risk of malignancy in patients with gallbladder lesions. Dyslipidemia is an independent risk factor for malignancy, regardless of the presence of the other risk factors and metabolic syndrome components.

Surgical outcomes of colonic stents as a bridge to surgery versus emergency surgery for malignant colorectal obstruction: A systematic review and meta-analysis of high quality prospective and randomised controlled trials

Self-expanding metallic stent placement as a bridge to surgery has been reported as an alternative to emergency surgery for acute malignant colorectal obstruction. However, results from clinical trials and previous meta-analyses are conflicting. We carried out a meta-analysis to compare the surgical and oncological outcomes between emergency surgery and self-expanding metallic stents for malignant large bowel obstruction. Pubmed, Embase, CINAHL, Web of Science and Cochrane were searched for prospective and randomised controlled trials. The outcomes of focus included 3- and 5-year overall and disease-free survival, overall tumour recurrence, overall complication and 30-day mortality rate, length of hospital and ICU stay, overall blood loss, number of patients requiring transfusion, total number of lymph nodes harvested, stoma and primary anastomosis rate. Twenty-seven studies were included with a total of 3894 patients. There was no significant difference in terms of 3-year and 5-year disease-free and overall survival. Stenting resulted in less blood loss (mean difference -234.72, P < 0.00001) and higher primary anastomosis rate (RR 1.25, P < 0.00001). For curative cases, bridge to surgery groups had lower 30-day mortality rate (RR 0.65, P = 0.01), lower overall complication rate (RR 0.65, P < 0.0001), more lymph nodes harvested (mean difference 2.51, P = 0.005), shorter ICU stay (mean difference -2.27, P = 0.02) and hospital stay (mean difference -7.24, 95% P < 0.0001). Compared to emergency surgery, self-expanding metallic stent interventions improve short-term surgical outcomes, especially in the curative setting, but have similar long-term oncological and survival outcomes.

A100 ORAL VANCOMYCIN THERAPY FOR CLOSTRIDIOIDES DIFFICILE INFECTION AND RISK OF INFECTION WITH GRAM-NEGATIVE ORGANISMS

Background

Vancomycin is the recommended first-line therapy for mild to severe Clostridioides difficile infection (CDI). However, oral vancomycin is associated with disruption of the indigenous microbiota, predisposing patients to overgrowth of endogenous pathogens such as vancomycin-resistant enterococci.

Aims

The primary objective of the study is to examine the effect of the treatment regimens of CDI on the risk of infection with gram-negative organisms in adult patients treated for CDI.

Methods

A retrospective cohort study of 319 adult patients treated for CDI at Hamilton Health Sciences in the year 2015. A multivariate logistic regression analysis was performed to determine if oral vancomycin-based therapy is associated with an increased risk of infection with gram-negative organisms after adjustment for other factors.

Results

Eighty-one patients were excluded because of recurrent episodes of CDI within the same year or missing information. 238 patients were included in the final analysis. 48 (20.2%) patients had positive culture for gram-negative organisms after onset of CDI. Urine was the most common source for gram-negative organisms (39/48, 81.3%) followed by blood (8/48,16.7%). The most common isolated gram-negative organisms were Escherichia coli (18/48, 37.5%) and Klebsiella pneumonia (9/48, 18.8%).

The most common CDI treatment regimens were metronidazole monotherapy (137/238, 57.6%), vancomycin monotherapy (13/238, 5.5%), and combination therapy (88/238, 37.0%). Among patients who were treated with metronidazole monotherapy, vancomycin monotherapy, and combination therapy, 30(30/137, 21.9%), 3 (3/13,23.1%), and 15 (15/88, 17.1%) had positive culture for gram-negative organisms, respectively (P= 0.6).

Ninety-seven (97/238,40.8%) patients had severe CDI, 40 (40/97, 41.2%) were treated with metronidazole monotherapy, 5(5/97, 5.2%) with vancomycin monotherapy, and 52 (52/97, 53.6%) with combination therapy. 26 (26/141,18.4%) and 22 (22/97, 22.7%) had positive culture for gram-negative organisms among patients with non-severe and severe CDI, receptively (P= 0.7). In the multivariate analysis, neither type of CDI treatment regimen (P=0.2, 95% CI 0.30–1.31) nor CDI severity (P=0.4, 95% CI 0.67–2.69) was associated an increased risk of infection with gram-negative organisms after CDI onset.

Conclusions

Contrary to the reported literature, we did not find that oral vancomycin-based CDI treatment was associated with increased risk of infection with gram-negative organisms.

Funding Agencies

None

P10.02 Differentiating microglia and tumour associated macrophages in high grade glioma

BACKGROUND

Glioblastoma multiforme (GBM) is the most common primary brain tumour that affects adults. This aggressive tumour is invariably fatal, carrying a rapid progression and a dismal median survival period of only 15 months despite multimodal treatment approaches. Central to GBM pathogenesis is the immunosuppressive profile of these tumours. The two cell types that are highly abundant in these tumours and play critical roles in the immunosuppressive niche are the brain’s resident microglia and their peripheral counterparts - tumour associated macrophages (TAMs). Despite microglia and TAMs being ontogenetically distinct, these cells have largely been grouped together in research owing to the previous lack of cell-specific markers. Recent evidence has suggested that although TAMs may hold a predominantly pro-tumoral role, microglia may adopt a more anti-tumoral phenotype. Therefore, the differentiation of these two cell types is critical in elucidating the potentially characteristic roles of these two cell types in GBM pathogenesis.

MATERIAL AND METHODS

Tissue sections from resected low- and high-grade glioma tumours, along with epilepsy tissue (control), were used for immunohistochemistry (IHC) staining of macrophage pan-makers (Iba1, CD45, PU.1) and microglial-specific markers (TMEM119, P2RY12). Marker co-localisation was then used to differentiate microglia from TAMs. We further investigated a wider subset of cell-specific markers using multicolour flow cytometry and immunocytochemical staining of isolated cells from patient tissue samples.

RESULTS

Immunofluorescent staining of glioma and epilepsy tissue revealed two clear populations of cells; one population displayed long processes and co-labelling for both pan- and microglial-specific markers, whilst the other population displayed an amoeboid phenotype with only pan-maker staining. Preliminary analysis comparing microglia/TAM populations in low-grade, high-grade and epilepsy tissue suggests a clear difference in the proportions of these cells.

CONCLUSION

Our work complements RNA-Seq studies, showing that TMEM119 and P2RY12, alongside other markers, can indeed identify two distinct myeloid cell populations within glioma tissue. This provides a strong basis for further study where we aim to elucidate the respective roles of microglia and TAMs within tumours. Ultimately, this may hold the potential for differential targeting of these cells using immunotherapies.

P10.03 Immunological differences between patient-matched normal-derived and GBM-derived pericytes

BACKGROUND

Glioblastoma Multiforme (GBM) is the most aggressive, fatal, yet most common form of brain malignancy in adults. Despite advances in immune-based treatments for other modes of cancer, GBM remains a challenge due to its ability to dampen immune responses via mechanisms not yet fully understood. With a median survival time of only 15 months following diagnosis, there is a strong push to find new targets for therapy. The microenvironment comprises a mixture of malignant tumour cells, stroma, blood vessels and infiltrating inflammatory cells. Despite advances in understanding the contribution of these cells in establishing an anti-inflammatory microenvironment, the contribution of pericytes, an important neurovascular mural cell that forms the blood-brain barrier, has been inadequately studied. Therefore, we investigated the differences in immune profile between patient-matched non-neoplastic brain- and GBM-derived pericytes under basal and induced conditions.

MATERIAL AND METHODS

Primary patient-matched non-neoplastic brain and GBM tumour derived pericytes were isolated from specimens excised from consenting patients undergoing GBM surgical resection at Auckland City Hospital. Pericytes were treated with inflammatory cytokines including IL-1β, IFN-γ, TNFα and TGFβ for up to 24 hours. Inflammatory profile changes were probed for using fluorescent immunocytochemistry, qRT-PCR and spectral flow cytometry. Media was also collected for secretome analysis via cytometric bead array.

RESULTS

GBM pericytes show decreased expression of CX3CL1, both basally and following IL-1β treatment, via qRT-PCR and CBA. In contrast, increased gene expression and secretion of IL-6 and IL-8 by GBM pericytes were observed. GBM pericytes also basally express CD90 and anti-inflammatory molecule PD-L1 compared to their normal counterparts. In terms of activated pathways, basal SMAD2/3 activation is increased in GBM pericytes, while also showing greater activation following treatment with IL-1β, IFN-γ but not TNFα. C/EBPδ is activated and translocated following inflammatory stimulation; however, shows localised expression within the cytoplasm only observed in GBM pericytes.

CONCLUSION

This immunological screen of GBM pericytes highlights them as key players in the establishment of the tumour microenvironment. With data suggesting the activation of pathways such as the SMAD2/3 pathway in an unconventional manner, it suggests the potential for pericytes to manipulate pathways towards a more immunosuppressive outcome. Further immune characterisation of such cells is required to fully understand how they might contribute to the immunosuppressive nature of GBM.

Modelling of the SDF-1/CXCR4 regulated in vivo homing of therapeutic mesenchymal stem/stromal cells in mice

Background

Mesenchymal stem/stromal cells (MSCs) are a promising tool for cell-based therapies in the treatment of tissue injury. The stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) axis plays a significant role in directing MSC homing to sites of injury. However in vivo MSC distribution following intravenous transplantation remains poorly understood, potentially hampering the precise prediction and evaluation of therapeutic efficacy.

Methods

A murine model of partial ischemia/reperfusion (I/R) is used to induce liver injury, increase the hepatic levels of SDF-1, and study in vivo MSC distribution. Hypoxia-preconditioning increases the expression of CXCR4 in human bone marrow-derived MSCs. Quantitative assays for human DNA using droplet digital PCR (ddPCR) allow us to examine the in vivo kinetics of intravenously infused human MSCs in mouse blood and liver. A mathematical model-based system is developed to characterize in vivo homing of human MSCs in mouse models with SDF-1 levels in liver and CXCR4 expression on the transfused MSCs. The model is calibrated to experimental data to provide novel estimates of relevant parameter values.

Results

Images of immunohistochemistry for SDF-1 in the mouse liver with I/R injury show a significantly higher SDF-1 level in the I/R injured liver than that in the control. Correspondingly, the ddPCR results illustrate a higher MSC concentration in the I/R injured liver than the normal liver. CXCR4 is overexpressed in hypoxia-preconditioned MSCs. An increased number of hypoxia-preconditioned MSCs in the I/R injured liver is observed from the ddPCR results. The model simulations align with the experimental data of control and hypoxia-preconditioned human MSC distribution in normal and injured mouse livers, and accurately predict the experimental outcomes with different MSC doses.

Discussion

The modelling results suggest that SDF-1 in organs is an effective in vivo attractant for MSCs through the SDF-1/CXCR4 axis and reveal the significance of the SDF-1/CXCR4 chemotaxis on in vivo homing of MSCs. This in vivo modelling approach allows qualitative characterization and prediction of the MSC homing to normal and injured organs on the basis of clinically accessible variables, such as the MSC dose and SDF-1 concentration in blood. This model could also be adapted to abnormal conditions and/or other types of circulating cells to predict in vivo homing patterns.

Surgical management and outcomes of 12 cases of Wilms tumour with intracardiac extension from a single centre

PURPOSE

To review demographics, effect of preoperative chemotherapy on tumour thrombus, imaging, operative strategy, and outcomes of 12 patients presenting with intracardiac extension of Wilms tumour thrombus.

METHODS

A retrospective audit was undertaken on patients with intracardiac extension of Wilms tumour. Patients were identified from the oncology database and information obtained on clinical presentation, stage, preoperative treatment, surgical procedures and complications, histology, and survival status. Ethics approval was obtained from the University of Cape Town Human Research Ethics Committee.

RESULTS

From 1984 to 2016, 337 children with Wilms tumour were treated. Twelve (3.6%) had intracardiac extension of tumour thrombus, nine into the right atrium, and three into the right ventricle. Ultrasound, computerized tomography, magnetic resonance imaging, and echocardiograms were used to assess thrombus level. Patients were staged as stage III(8) and IV(4). All patients received preoperative chemotherapy. Thrombus retracted from the heart in two cases. One patient died preoperatively. Eleven underwent laparotomy, median sternotomy, and cardiopulmonary bypass (CPB). Four underwent cavectomy. Five required cavoatrial patches. Thrombus extending into the hepatic veins was extracted in five patients. There was one intraoperative complication and one perioperative death. Thrombus histology showed viable tumour in 9 of 11 patients. Three patients died of progressive disease. Seven patients are currently disease free.

CONCLUSION

A combination of imaging is required to determine thrombus extent, and this facilitates surgical planning. Preoperative chemotherapy may cause thrombus regression, thus avoiding CPB. CPB offers appropriate conditions for safe tumour thrombus excision. Full management in centres with appropriately experienced staff and facilities for CPB is recommended.

Concise Review: Quantitative Detection and Modeling the In Vivo Kinetics of Therapeutic Mesenchymal Stem/Stromal Cells

Mesenchymal stem/stromal cells (MSCs) present a promising tool in cell‐based therapy for treatment of various diseases. Currently, optimization of treatment protocols in clinical studies is complicated by the variations in cell dosing, diverse methods used to deliver MSCs, and the variety of methods used for tracking MSCs in vivo. Most studies use a dose escalation approach, and attempt to correlate efficacy with total cell dose. Optimization could be accelerated through specific understanding of MSC distribution in vivo, long‐term viability, as well as their biological fate. While it is not possible to quantitatively detect MSCs in most targeted organs over long time periods after systemic administration in clinical trials, it is increasingly possible to apply pharmacokinetic modeling to predict their distribution and persistence. This Review outlines current understanding of the in vivo kinetics of exogenously administered MSCs, provides a critical analysis of the methods used for quantitative MSC detection in these studies, and discusses the application of pharmacokinetic modeling to these data. Finally, we provide insights on and perspectives for future development of effective therapeutic strategies using pharmacokinetic modeling to maximize MSC therapy and minimize potential side effects. Stem Cells Translational Medicine2018;7:78–86

Glutathione Peroxidase Activity, Plasma Total Antioxidant Capacity, and Urinary F2- Isoprostanes as Markers of Oxidative Stress in Anemic Dogs

Background

Oxidative stress plays a role in the pathophysiology of several diseases and has been documented as a contributor to disease in both the human and veterinary literature. One at‐risk cell is the erythrocyte, however, the role of oxidative stress in anemia in dogs has not been widely investigated.

Hypothesis/Objective

Anemic dogs will have an alteration in the activity of glutathione peroxidase (GPx), a decrease in of total antioxidant capacity (TAC), and an increased concentration of urinary 15‐F₂‐isoprostanes (F₂‐IsoP) when compared to healthy dogs.

Animals

40 client‐owned dogs with anemia (PCV <30%) age‐matched to 40 client‐owned healthy control dogs.

Methods

Prospective, cross‐sectional study. Whole blood GPx activity, plasma TAC, and urinary F₂‐isoprostane concentrations were evaluated in each dog and compared between groups.

Results

Anemic dogs had significantly lower GPx activity (43.1 × 10³ +/‐ 1.6 × 10³ U/L) than did dogs in the control group (75.8 × 10³ +/‐ 2.0 × 10³ U/L; P < 0.0001). The GPx activity in dogs with hemolysis (10³ +/‐ 0.8 × 10³ U/L) was not significantly different (P = 0.57) than in dogs with nonhemolytic anemia (43.5 × 10³ +/‐ 1.1 × 10³ U/L). The TAC concentrations (P = 0.15) and urinary F₂‐isoprostanes (P = 0.73) did not significantly differ between groups.

Conclusions and Clinical Importance

Glutathione peroxidase activity was significantly decreased in anemic dogs indicating oxidative stress. Additional studies are warranted to determine if antioxidant supplementation would improve survival and overall outcome as part of a therapeutic regimen for anemic dogs.