The use of microphysiological systems to model metastatic cancer.

Cancer is one of the leading causes of death in the 21st century, with metastasis of cancer attributing to 90% of cancer-related deaths. Therefore, to improve patient outcomes there is a need for better preclinical models to increase the success of translating oncological therapies into the clinic. Current traditional staticin vitromodels lack a perfusable network which is critical to overcome the diffusional mass transfer limit to provide a mechanism for the exchange of essential nutrients and waste removal, and increase their physiological relevance. Furthermore, these models typically lack cellular heterogeneity and key components of the immune system and tumour microenvironment. This review explores rapidly developing strategies utilising perfusable microphysiological systems (MPS) for investigating cancer cell metastasis. In this review we initially outline the mechanisms of cancer metastasis, highlighting key steps and identifying the current gaps in our understanding of the metastatic cascade, exploring MPS focused on investigating the individual steps of the metastatic cascade before detailing the latest MPS which can investigate multiple components of the cascade. This review then focuses on the factors which can affect the performance of an MPS designed for cancer applications with a final discussion summarising the challenges and future directions for the use of MPS for cancer models.

Development of PCL PolyHIPE Substrates for 3D Breast Cancer Cell Culture.

Cancer is a becoming a huge social and economic burden on society, becoming one of the most significant barriers to life expectancy in the 21st century. In particular, breast cancer is one of the leading causes of death for women. One of the most significant difficulties to finding efficient therapies for specific cancers, such as breast cancer, is the efficiency and ease of drug development and testing. Tissue-engineered (TE) in vitro models are rapidly developing as an alternative to animal testing for pharmaceuticals. Additionally, porosity included within these structures overcomes the diffusional mass transfer limit whilst enabling cell infiltration and integration with surrounding tissue. Within this study, we investigated the use of high-molecular-weight polycaprolactone methacrylate (PCL-M) polymerised high-internal-phase emulsions (polyHIPEs) as a scaffold to support 3D breast cancer (MDA-MB-231) cell culture. We assessed the porosity, interconnectivity, and morphology of the polyHIPEs when varying mixing speed during formation of the emulsion, successfully demonstrating the tunability of these polyHIPEs. An ex ovo chick chorioallantoic membrane assay identified the scaffolds as bioinert, with biocompatible properties within a vascularised tissue. Furthermore, in vitro assessment of cell attachment and proliferation showed promising potential for the use of PCL polyHIPEs to support cell growth. Our results demonstrate that PCL polyHIPEs are a promising material to support cancer cell growth with tuneable porosity and interconnectivity for the fabrication of perfusable 3D cancer models.

Gelatin-containing porous polycaprolactone PolyHIPEs as substrates for 3D breast cancer cell culture and vascular infiltration.

Tumour survival and growth are reliant on angiogenesis, the formation of new blood vessels, to facilitate nutrient and waste exchange and, importantly, provide a route for metastasis from a primary to a secondary site. Whilst current models can ensure the transport and exchange of nutrients and waste via diffusion over distances greater than 200 µm, many lack sufficient vasculature capable of recapitulating the tumour microenvironment and, thus, metastasis. In this study, we utilise gelatin-containing polymerised high internal phase emulsion (polyHIPE) templated polycaprolactone-methacrylate (PCL-M) scaffolds to fabricate a composite material to support the 3D culture of MDA-MB-231 breast cancer cells and vascular ingrowth. Firstly, we investigated the effect of gelatin within the scaffolds on the mechanical and chemical properties using compression testing and FTIR spectroscopy, respectively. Initial in vitro assessment of cell metabolic activity and vascular endothelial growth factor expression demonstrated that gelatin-containing PCL-M polyHIPEs are capable of supporting 3D breast cancer cell growth. We then utilised the chick chorioallantoic membrane (CAM) assay to assess the angiogenic potential of cell-seeded gelatin-containing PCL-M polyHIPEs, and vascular ingrowth within cell-seeded, surfactant and gelatin-containing scaffolds was investigated via histological staining. Overall, our study proposes a promising composite material to fabricate a substrate to support the 3D culture of cancer cells and vascular ingrowth.

Megarectum: systematic histopathological evaluation of 35 patients and new common pathways in chronic rectal dilatation.

AIMS: Megarectum is well described in the surgical literature but few contemporary pathological studies have been undertaken. There is uncertainty whether 'idiopathic' megarectum is a primary neuromuscular disorder or whether chronic dilatation leads to previously reported and unreported pathological changes. We sought to answer this question. METHODS: Systematic histopathological evaluation (in accord with international guidance) of 35 consecutive patients undergoing rectal excision surgery for megarectum (primary: n=24) or megarectum following surgical correction of anorectal malformation (secondary: n=11) in a UK university hospital with adult/paediatric surgical and gastrointestinal neuropathology expertise. RESULTS: We confirmed some previously reported observations, notably hypertrophy of the muscularis propria (27 of 35, 77.1% of patients) and extensive fibrosis (30 of 35, 85.7% of patients). We also observed unique and previously unreported features including elastosis (19 of 33, 57.6%) and the presence of polyglucosan bodies (15 of 32, 46.9% of patients). In contrast to previous literature, few patients had any strong evidence of specific forms of visceral neuropathy (5 of 35, including 3 plexus duplications) or myopathy (6 of 35, including 3 muscle duplications). All major pathological findings were common to both primary and secondary forms of the disease, implying that these may be a response to chronic rectal distension rather than of primary aetiology. CONCLUSIONS: In the largest case series reported to date, we challenge the current perception of idiopathic megarectum as a primary neuromuscular disease and propose a cellular pathway model for the features present. The severe morphological changes account for some of the irreversibility of the condition and reinforce the need to prevent ongoing rectal distension when first identified.

The impact of frailty on clinical outcomes in colorectal cancer surgery: a systematic literature review.

BACKGROUND: The majority of colorectal cancer is diagnosed in people aged >65 years, yet the elderly are less likely to undergo curative surgery. Chronological age is poorly correlated with post-operative outcomes and is not an acceptable measure of risk. Conversely, frailty is a strong predictor of poor post-operative outcomes and presents an opportunity for optimisation. This systematic review aims to assess the evidence between frailty and outcomes in patients of all ages undergoing colorectal cancer resections and to compare the predictive value of frailty status to that of age alone. METHODS: The review was registered on Prospero, CRD42019150542. PubMed was searched for articles reporting outcomes for frail patients undergoing elective or emergency colorectal cancer resection up until August 2019. All studies reporting outcomes in frail patients were deemed eligible for inclusion and assessed according to the PRISMA guidelines. RESULTS: Of the 143 identified studies, 17 were eligible for inclusion. Study type, frailty assessments and outcomes measured were highly variable. 'Frailty' was associated with significantly higher rates of post-operative complications (7/7 studies), post-operative mortality (5/7 studies), readmission (3/4 studies) and length of stay (3/3 studies). Seven of 11 studies reported no association between age and adverse outcomes. CONCLUSION: Frailty is a predictor of poor clinical outcomes in patients undergoing surgery for colorectal cancer. Standardisation of frailty assessment and outcome measure is needed. Accurate risk stratification of patients will allow us to make informed treatment decisions, identify patients who may benefit from preoperative intervention and tailor post-operative care.

An innovative training and recruitment programme in surgery.

INTRODUCTION: Staff shortages and rising locum costs prompted Barking, Havering and Redbridge University Hospitals NHS Trust to design an innovative training pathway for doctors in surgery. The 'Academy of Surgery' is a 2-year structured educational programme with rotations through surgical and emergency care specialties and includes a funded MSc. METHODS: We recruited 27 doctors over a 2-year period. The first cohort started in October 2018, the second in October 2019. These doctors are heavily supervised in a 2-year programme that aims to prepare them for higher specialty training. They undergo regular assessment and annual review of competencies and progression. They receive regular formal classroom teaching and there are regular sessions to discuss welfare. RESULTS: Surgical rotas are now fully staffed and not reliant on locum doctors. This has led to significant cost savings. Locum spending in 2017 was £3,856,000 vs £1,284,000 in 2020 - a net saving of £1,187,000 over 2 years. CONCLUSION: This innovative training programme has contributed to full staffing of a number of surgical rotas within our Trust and delivered a large financial saving for the NHS. We hope to expand this work into neighbouring trusts.

Revisional ileoanal pouch surgery: a systematic literature review assessing outcomes over the last 40 years.

AIM: Failure of primary ileal pouch-anal anastomosis (IPAA) occurs in up to 15% of patients. Revision surgery may be offered to patients wishing to maintain gastrointestinal continuity. This paper explores the literature relating to IPAA revision surgery, focusing on pouch function after revision and factors associated with pouch failure. METHODS: Search of PubMed database was carried out for 'ileal pouch anal anastomoses', 'ileoanal pouch', 'restorative proctocolectomy', 'revision surgery', 'redo surgery', 'failure', 'refashion surgery', 'reconstruction surgery' and 'salvage surgery'. Papers were screened using the PRISMA literature review strategy. Studies of adults published after 1980 in English with an available abstract were included. Case reports and studies that were superseded using the same data were excluded. RESULTS: Nineteen papers (1424 patients) were identified. Bowel motion frequency doubled following revision surgery compared to primary IPAA although the increase was not always statistically significant. In patients failing primary IPAA, frequency of daytime bowel motions improved following revision in three studies but only reached significance in one (12.1 vs. 6.9, P = 0.021). Risk of pouch failure is increased in patients who develop pelvic sepsis after the primary procedure with the largest study demonstrating a four-fold increased risk (hazard ratio 3.691, P < 0.0001). A final diagnosis of Crohn's causes a four-fold increased risk of pouch failure (n = 81; OR 3.92, 95% CI 1.1-15.9, P = 0.04). CONCLUSIONS: In patients undergoing revisional surgery, improved outcomes are observed but are inferior compared to primary IPAA patients. Pelvic sepsis after primary IPAA and a final diagnosis of Crohn's are associated with increased risk of pouch failure.

Sarcoma treatment in the era of molecular medicine.

Sarcomas are heterogeneous and clinically challenging soft tissue and bone cancers. Although constituting only 1% of all human malignancies, sarcomas represent the second most common type of solid tumors in children and adolescents and comprise an important group of secondary malignancies. More than 100 histological subtypes have been characterized to date, and many more are being discovered due to molecular profiling. Owing to their mostly aggressive biological behavior, relative rarity, and occurrence at virtually every anatomical site, many sarcoma subtypes are in particular difficult-to-treat categories. Current multimodal treatment concepts combine surgery, polychemotherapy (with/without local hyperthermia), irradiation, immunotherapy, and/or targeted therapeutics. Recent scientific advancements have enabled a more precise molecular characterization of sarcoma subtypes and revealed novel therapeutic targets and prognostic/predictive biomarkers. This review aims at providing a comprehensive overview of the latest advances in the molecular biology of sarcomas and their effects on clinical oncology; it is meant for a broad readership ranging from novices to experts in the field of sarcoma.

Management of cardiac arrest following blunt trauma: a critical evaluation of resuscitative thoracotomy.

Survival rates in patients who sustain cardiac arrest following blunt trauma are suboptimal. Although resuscitative thoracotomy is advocated for managing patients who present with penetrating trauma, its use in blunt trauma is controversial because it has been consistently shown to produce suboptimal outcomes. This article examines some of the challenges associated with decision-making regarding the management of patients with cardiac arrest following blunt trauma, critically evaluates the role of resuscitative thoracotomy and considers some novel interventions that may provide clinicians with alternative management options.

Debunking the Myth of the Endogenous Antiangiogenic Vegfaxxxb Transcripts.

In this opinion article we critically assess evidence for the existence of a family of antiangiogenic vascular endothelial growth factor (Vegfaxxxb) transcripts, arising from the use of a phylogenetically conserved alternative distal splice site within exon 8 of the VEGFA gene. We explain that prior evidence for Vegfaxxxb transcripts in tissues rests heavily upon flawed RT-PCR methodologies, with the extensive use of 5'-tailing in primer design being the main issue. Furthermore, our analysis of large RNA-seq data sets (human and ovine) fails to identify a single Vegfaxxxb transcript. Therefore, we challenge the very existence of Vegfaxxxb transcripts, which further questions the physiological relevance of studies based on the use of 'anti-VEGFAxxxb' antibodies. Our analysis has implications for the proposed therapeutic use of isoform-specific anti-VEGFA strategies for treating cancer and retinopathies.

Health Optimization Program for Elders: Improving the Transition From Hospital to Skilled Nursing Facility.

BACKGROUND: Individuals discharged from the hospital to skilled nursing facilities (SNFs) experience high rates of unplanned hospital readmission, indicating opportunity for improvement in transitional care. LOCAL PROBLEM: Local physicians providing care in SNFs were not associated with the discharging hospital health care system. As a result, substantive real-time communication between hospital and SNF physicians was not occurring. METHODS: A multidisciplinary team developed and monitored implementation of the Health Optimization Program for Elders (HOPE) to improve patient transitions from acute hospital stay to SNFs. INTERVENTIONS: The HOPE used a nurse practitioner (NP) to identify geriatric syndromes, set patient/caregiver expectations, assess rehabilitation potential, clarify goals of care, and communicate information directly to SNF providers. RESULTS: The intervention was feasible, addressed unmet needs and errors in the SNF transition process, and was associated with lower 30-day readmission rates compared with concurrent patients not enrolled in the HOPE. CONCLUSIONS: An NP-led hospital to SNF transitional care program is a promising means of improving hospital to SNF transitions.

MDMA toxicity: management of acute and life-threatening presentations.

Since the 1980s, methylenedioxymethamphetamine (MDMA) has been a popular recreational drug, used particularly among those who attend raves and nightclubs. Over the past 3 years, the popularity of this drug has once again increased and there has been an associated rise in deaths. The pathophysiology of MDMA toxicity is complex and much remains to be understood. This article aims to increase readers' knowledge of patient presentations, the pathophysiology behind life-threatening toxicity, current treatments and the use of extracorporeal membrane oxygenation as a potential future treatment.

Tissue Inhibitor of Metalloproteinase-3 (TIMP-3) induces FAS dependent apoptosis in human vascular smooth muscle cells.

Over expression of Tissue Inhibitor of Metalloproteinases-3 (TIMP-3) in vascular smooth muscle cells (VSMCs) induces apoptosis and reduces neointima formation occurring after saphenous vein interposition grafting or coronary stenting. In studies to address the mechanism of TIMP-3-driven apoptosis in human VSMCs we find that TIMP-3 increased activation of caspase-8 and apoptosis was inhibited by expression of Cytokine response modifier A (CrmA) and dominant negative FAS-Associated protein with Death Domain (FADD). TIMP-3 induced apoptosis did not cause mitochondrial depolarisation, increase activation of caspase-9 and was not inhibited by over-expression of B-cell Lymphoma 2 (Bcl2), indicating a mitochondrial independent/type-I death receptor pathway. TIMP-3 increased levels of the First Apoptosis Signal receptor (FAS) and depletion of FAS with shRNA showed TIMP-3-induced apoptosis was FAS dependent. TIMP-3 induced formation of the Death-Inducing Signalling Complex (DISC), as detected by immunoprecipitation and by immunofluorescence. Cellular-FADD-like IL-1 converting enzyme-Like Inhibitory Protein (c-FLIP) localised with FAS at the cell periphery in the absence of TIMP-3 and this localisation was lost on TIMP-3 expression with c-FLIP adopting a perinuclear localisation. Although TIMP-3 inhibited FAS shedding, this did not increase total surface levels of FAS but instead increased FAS levels within localised regions at the cell surface. A Disintegrin And Metalloproteinase 17 (ADAM17) is inhibited by TIMP-3 and depletion of ADAM17 with shRNA significantly decreased FAS shedding. However ADAM17 depletion did not induce apoptosis or replicate the effects of TIMP-3 by increasing localised clustering of cell surface FAS. ADAM17-depleted cells could activate caspase-3 when expressing levels of TIMP-3 that were otherwise sub-apoptotic, suggesting a partial role for ADAM17 mediated ectodomain shedding in TIMP-3 mediated apoptosis. We conclude that TIMP-3 induced apoptosis in VSMCs is highly dependent on FAS and is associated with changes in FAS and c-FLIP localisation, but is not solely dependent on shedding of the FAS ectodomain.

ADAM9 is present at endothelial cell - cell junctions and regulates monocyte - endothelial transmigration.

We have found that A Disintegrin And Metalloproteinase-9 (ADAM9) localises to cell-cell junctions with VE-Cadherin in confluent endothelial monolayers. Co-cultures of cells separately transfected with ADAM9-EGFP or ADAM9-HA showed expression is required in two adjacent cells for localisation to cell-cell junctions suggesting the ADAM9 ectodomain may self-associate. A direct interaction between ADAM9 ectodomains was confirmed using recombinant proteins and an ELISA based method. As the ADAM9 ectodomain can also exist as a soluble form physiologically, we examined if this could inhibit endothelial functions dependent on cell-cell junctions. The soluble ADAM9 ectodomain could not increase endothelial monolayer permeability or inhibit monocyte-endothelial adhesion, but could inhibit monocyte-endothelial transmigration. These novel findings point to ADAM9 playing an important role in endothelial cell biology that is distinct from the other ADAMs.

Differential Expression of VEGFA Isoforms Regulates Metastasis and Response to Anti-VEGFA Therapy in Sarcoma.

Elevated plasma concentrations of soluble VEGFA isoforms are associated with poor prognosis in parallel with improved response to treatment with the anti-VEGFA antibody bevacizumab. To uncover the underlying mechanism to these observations, we administered anti-VEGFA therapy to mice bearing luminescent mouse fibrosarcomas expressing single VEGFA isoforms or their wild-type counterparts expressing all isoforms (fs120, fs164, fs188, or fsWT). Expression of the more soluble isoforms conferred an advantage for lung metastasis from subcutaneous tumors (fs120/164 vs. fs188/WT); fs120 cells also produced more lung colonies than fs188 cells when injected intravenously. Metastasis from subcutaneous fs120 tumors was more sensitive than fs188 to treatment with the anti-VEGFA antibody B20-4.1.1. Despite elevated plasma levels of VEGFA in fs120 tumor-bearing mice and a dependence on VEGF receptor 1 activity for metastasis to the lung, B20-4.1.1 did not affect survival in the lung on intravenous injection. B20-4.1.1 inhibited subcutaneous tumor growth and decreased vascular density in both fs120 and fs188 tumors. However, migration of fs120, but not fs188 cells, in vitro was inhibited by B20-4.1.1. The greater survival of fs120 cells in the lung was associated with VEGFR1-dependent accumulation of CD11b-positive myeloid cells and higher expression of the VEGFR1 ligand, PlGF2, by the fs120 cells in vitro and in the plasma and lungs of fs120 tumor-bearing mice. We conclude that soluble VEGFA isoform expression increases fibrosarcoma metastasis through multiple mechanisms that vary in their sensitivity to anti-VEGF/VEGFR inhibition, with VEGFA-targeted therapy suppressing metastasis through effects on the primary tumor rather than the metastatic site. Cancer Res; 77(10); 2633-46. ©2017 AACR.

Investigating Neovascularization in Rat Decellularized Intestine: An In Vitro Platform for Studying Angiogenesis.

One of the main challenges currently faced by tissue engineers is the loss of tissues postimplantation due to delayed neovascularization. Several strategies are under investigation to create vascularized tissue, but none have yet overcome this problem. In this study, we produced a decellularized natural vascular scaffold from rat intestine to use as an in vitro platform for neovascularization studies for tissue-engineered constructs. Decellularization resulted in almost complete (97%) removal of nuclei and DNA, while collagen, glycosaminoglycan, and laminin content were preserved. Decellularization did, however, result in the loss of elastin and fibronectin. Some proangiogenic factors were retained, as fragments of decellularized intestine were able to stimulate angiogenesis in the chick chorioallantoic membrane assay. We demonstrated that decellularization left perfusable vascular channels intact, and these could be repopulated with human dermal microvascular endothelial cells. Optimization of reendothelialization of the vascular channels showed that this was improved by continuous perfusion of the vasculature and further improved by infusion of human dermal fibroblasts into the intestinal lumen, from where they invaded into the decellularized tissue. Finally we explored the ability of the perfused cells to form new vessels. In the absence of exogenous angiogenic stimuli, Dll4, a marker of endothelial capillary-tip cell activation during sprouting angiogenesis, was absent, indicating that the reformed vasculature was largely quiescent. However, after addition of vascular endothelial growth factor A, Dll4-positive endothelial cells could be detected, demonstrating that this engineered vascular construct maintained its capacity for neovascularization. In summary, we have demonstrated how a natural xenobiotic vasculature can be used as an in vitro model platform to study neovascularization and provide information on factors that are critical for efficient reendothelialization of decellularized tissue.

Fabrication of Biodegradable Synthetic Vascular Networks and Their Use as a Model of Angiogenesis.

One of the greatest challenges currently faced in tissue engineering is the incorporation of vascular networks within tissue-engineered constructs. The aim of this study was to develop a technique for producing a perfusable, 3-dimensional, cell-friendly model of vascular structures that could be used to study the factors affecting angiogenesis and vascular biology in engineered systems in more detail. Initially, biodegradable synthetic pseudovascular networks were produced via the combination of robocasting and electrospinning techniques. The internal surfaces of the vascular channels were then recellularized with human dermal microvascular endothelial cells (HDMECs) with and without the presence of human dermal fibroblasts (HDFs) on the outer surface of the scaffold. After 7 days in culture, channels that had been reseeded with HDMECs alone demonstrated irregular cell coverage. However, when using a co-culture of HDMECs inside and HDFs outside the vascular channels, coverage was found to be continuous throughout the internal channel. Using this cell combination, collagen gels loaded with vascular endothelial growth factor were deposited onto the outer surface of the scaffold and cultured for a further 7 days. After this, endothelial cell outgrowth from within the channels into the collagen gel was observed, showing that the engineered vasculature maintains its capacity for angiogenesis. Furthermore, the HDMECs appeared to have formed perfusable tubules within the gel. These results show promising steps towards the development of an in vitro platform for studying angiogenesis and vascular biology in a tissue engineering context.

Tumour cells expressing single VEGF isoforms display distinct growth, survival and migration characteristics.

Vascular endothelial growth factor-A (VEGF) is produced by most cancer cells as multiple isoforms, which display distinct biological activities. VEGF plays an undisputed role in tumour growth, vascularisation and metastasis; nevertheless the functions of individual isoforms in these processes remain poorly understood. We investigated the effects of three main murine isoforms (VEGF188, 164 and 120) on tumour cell behaviour, using a panel of fibrosarcoma cells we developed that express them individually under endogenous promoter control. Fibrosarcomas expressing only VEGF188 (fs188) or wild type controls (fswt) were typically mesenchymal, formed ruffles and displayed strong matrix-binding activity. VEGF164- and VEGF120-producing cells (fs164 and fs120 respectively) were less typically mesenchymal, lacked ruffles but formed abundant cell-cell contacts. On 3D collagen, fs188 cells remained mesenchymal while fs164 and fs120 cells adopted rounded/amoeboid and a mix of rounded and elongated morphologies respectively. Consistent with their mesenchymal characteristics, fs188 cells migrated significantly faster than fs164 or fs120 cells on 2D surfaces while contractility inhibitors accelerated fs164 and fs120 cell migration. VEGF164/VEGF120 expression correlated with faster proliferation rates and lower levels of spontaneous apoptosis than VEGF188 expression. Nevertheless, VEGF188 was associated with constitutively active/phosphorylated AKT, ERK1/2 and Stat3 proteins. Differences in proliferation rates and apoptosis could be explained by defective signalling downstream of pAKT to FOXO and GSK3 in fs188 and fswt cells, which also correlated with p27/p21 cyclin-dependent kinase inhibitor over-expression. All cells expressed tyrosine kinase VEGF receptors, but these were not active/activatable suggesting that inherent differences between the cell lines are governed by endogenous VEGF isoform expression through complex interactions that are independent of tyrosine kinase receptor activation. VEGF isoforms are emerging as potential biomarkers for anti-VEGF therapies. Our results reveal novel roles of individual isoforms associated with cancer growth and metastasis and highlight the importance of understanding their diverse actions.