Enhanced Biomimetics of Three-Dimensional Osteosarcoma Models: A Scoping Review

This scoping review evaluated 3D osteosarcoma (OS) models' biomimicry, examining their ability to mimic the tumour microenvironment (TME) and their drug sensitivity. Adhering to PRISMA-ScR guidelines, the systematic search revealed 293 studies, with 70 selected for final analysis. Overall, 64% of 3D OS models were scaffold-based, compared to self-generated spheroid models. Scaffolds generated using native matrix were most common (42%) with collagen I/hydroxyapatite predominating. Both scaffold-based and scaffold-free models were used equally for drug screening. The sensitivity of cancer cells in 3D was reported to be lower than that of cells in 2D in ~90% of the drug screening studies. This correlates with the observed upregulation of drug resistance. OS cells cultured in extracellular matrix (ECM)-mimetic scaffolds and native biomaterials were more resistant than cells in 2D. Co-cultures of OS and stromal cells in 3D models enhanced osteogenic differentiation, ECM remodelling, mineralisation, and angiogenesis, suggesting that tumour-stroma crosstalk promotes disease progression. Seven studies demonstrated selective toxicity of chemotherapeutics towards OS cells while sparing stromal cells, providing useful evidence for developing biomimetic tumour-stroma models to test selective drug toxicity. In conclusion, this review highlights the need to enhance biomimicry in 3D OS models for TME recapitulation, especially in testing novel therapeutics. Future research should explore innovative 3D biomimetic models, biomaterials, and advancements in personalised medicine.

A Cross-Sectional Study on Inequity and Unmet Needs in Conducting Systematic Reviews (SRMA) and Meta-Analysis Among Medical Students and Junior Doctors

Background

Systematic reviews and meta-analyses allow a transparent, rigorous, and replicable analysis to summarize the results of multiple related studies and are considered top of the evidence-based medicine study hierarchy. The COVID-19 pandemic has shed light on the unmet educational needs of students worldwide, notably those from underprivileged backgrounds. This cross-sectional study aimed to ascertain students' and junior doctors' attitudes on their current knowledge, confidence and preparedness of appraising and conducting systematic reviews and meta-analysis internationally.

Methods

A free online webinar was held in May 2021 by the senior author and a pre-event questionnaire was distributed. Responses collected were used for analysis anonymously to ascertain students' knowledge, experience, and confidence in preparing a systematic review and meta-analysis using a 1-5 Likert scale using IBM SPSS 26.0. Associations were examined using Chi-square and crosstabs analysis.

Results

Out of 2004 responses from 104 countries included in the analysis, the majority of delegates were from lower middle-income countries and were not familiar with the PRISMA checklist (59.2% and 81.1% respectively of the total number of participants). The majority had never attended any formal training (83%) and felt their medical institute gave them minimal advice (72.5%) in preparing systematic reviews. Among those who had attended formal training, the proportion was significantly higher in those belonging to high and upper middle-income countries combined (20.3%) than lower and lower-middle-income countries combined (15%).

Conclusion

This study highlights gaps that need addressing to enhance the knowledge of medical students and junior doctors performing systematic reviews and meta-analyses. Clear disparities are found in country income and the level of education. Future large-scale studies are needed to understand the rationale of working on online research projects and the opportunities available to medical students and junior doctors that may lead to medical curriculum changes.

FRI0448 FOUR CASES OF SYPHILIS MIMICKING RHEUMATOLOGICAL CONDITIONS PRESENTING TO THE GENERAL RHEUMATOLOGY SERVICE AT ST GEORGES HOSPITAL, LONDON, UK IN 2018-2019

Background:

Sir William Osler once wrote: “He, who knows syphilis, knows medicine”.

Whilst the Tuskegee Syphilis trials live in infamy, the advent of succesful penicillin treatment and sexual health education resulted in the lowest recorded incidence ever in 20011.

Unfortunately, cases of syphilis have nearly tripled in the past decade (from 2,847 in 2009 to 7,541 in 2018 in the UK)1. WHO now estimates the global median prevalence of Syphilis, among men who have sex with men, is 6%2

The current cohort of clinicians will therefore have limited clinical experience of Syphilis, which can often mimic rheumatic conditions. We present the clinical experience of a tertiary teaching centre hospital.

Objectives:

To identify the scope of clinical cases, with a diagnosis of Syphilis, during 2018-2019 at St Georges University Hospital, London, UK.

Methods:

Clinical cases were identified by health professionals and a retrospective review of medical records was undertaken.

Results:

There were 4 cases identified during 2018-19.

PatientAgeSexPast Medical HistorySymptomatologyRisk FactorsPresumed DiagnosisSerology169MaleHypertensionGCABilateral visual loss, rashMSMPrednisoloneTocilizumabGCA-related visual lossRPR 1:64TPPA 1: 10248246FemaleNilJoint pain and swelling, rashHepatitis B Core Antibody positiveUndifferentiatedInflammatory ArthritisRPR 1: 16340MaleNilJoint pain, alopecia, uveitis and rash, weight lossMSMPrimary SyphilisRPR 1: 16TPPA 1: 10248486FemalePulmonary Sarcoidosis, Squamous cell carcinoma of left maxillary sinusLower motor neuron facial nerve palsyPrednisoloneSarcoidosisRPR 1:4TPPA 1:80

GCA: Giant cell arteritis, MSM: Men who have sex with men, RPR: rapid plasma regain, TPPA: Treponema pallidum particle agglutination assay

Case 1:The patient was diagnosed with bilateral uveitis secondary to primary syphilis, and immunosuppression may have contributed to this.

Case 2:The rash developed after the initial presentation and an extended infection screen was performed.

Case 3:The patient had a 6 month duration of symptoms and had had a negative sexual health screen 1 year prior to presentation.

Case 4:The patient had no features of extra pulmonary sarcoidosis and an infectious screen was undertaken.

All 4 cases were referred to the Infectious Disease Unit for treatment. 3 patients received standard treatment with Penicillin, and 1 patient received an oral course of Doxycycline, due to a penicillin allergy.

2 of the 4 cases had complete resolution of symptoms, and 2 of the cases had only partial resolution of symptoms at the time of publication.

Conclusion:

Syphilis can present with an inflammatory arthritis, PMR and GCA –type symptoms, ocular inflammation, neurological disturbance and rashes that can mimic autoimmune conditions.

Our cases highlight the increasing incidence, as well as the risk of reactivation following immunosuppression. Current practice does not advise routine testing for syphilis prior to initiation of immunosuppressive therapy. However the rising incidence should prompt careful evaluation, and detailed sexual history, particularly in high risk groups. The diagnostic test interpretation and treatment requires close collaboration with Infectious Diseases Specialists.

References:

[1]https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/805903/2018_Table_1_STI_diagnoses_and_rates_in_England_by_gender.ods

[2]Report on global sexually transmitted infection surveillance 2018, WHO, ISBN: 978-92-4-156569-1

Disclosure of Interests:

None declared

Differential expression of miRNAs in pancreatobiliary type of periampullary adenocarcinoma and its associated stroma

Periampullary adenocarcinomas can be of two histological subtypes, intestinal or pancreatobiliary. The latter is more frequent and aggressive, and characterized by a prominent desmoplastic stroma, which is tightly related to the biology of the cancer, including its poor response to chemotherapy. Whereas miRNAs are known to regulate various cellular processes and interactions between cells, their exact role in periampullary carcinoma remains to be characterized, especially with respect to the prominent stromal component of pancreatobiliary type cancers. The present study aimed at elucidating this role by miRNA expression profiling of the carcinomatous and stromal component in twenty periampullary adenocarcinomas of pancreatobiliary type. miRNA expression profiles were compared between carcinoma cells, stromal cells and normal tissue samples. A total of 43 miRNAs were found to be differentially expressed between carcinoma and stroma of which 11 belong to three miRNA families (miR-17, miR-15 and miR-515). The levels of expression of miRNAs miR-17, miR-20a, miR-20b, miR-223, miR-10b, miR-2964a and miR-342 were observed to be higher and miR-519e to be lower in the stromal component compared to the carcinomatous and normal components. They follow a trend where expression in stroma is highest followed by carcinoma and then normal tissue. Pathway analysis revealed that pathways regulating tumor-stroma interactions such as ECM interaction remodeling, epithelial-mesenchymal transition, focal adhesion pathway, TGF-beta, MAPK signaling, axon guidance and endocytosis were differently regulated. The miRNA-mRNA mediated interactions between carcinoma and stromal cells add new knowledge regarding tumor-stroma interactions.

Molecular signatures of mRNAs and miRNAs as prognostic biomarkers in pancreatobiliary and intestinal types of periampullary adenocarcinomas

Periampullary adenocarcinomas include four anatomical sites of origin (the pancreatic duct, bile duct, ampulla and duodenum) and most of them fall into two histological subgroups (pancreatobiliary and intestinal). Determining the exact origin of the tumor is sometimes difficult, due to overlapping histopathological characteristics. The prognosis depends on the histological subtype, as well as on the anatomical site of origin, the former being the more important. The molecular basis for these differences in prognosis is poorly understood. Whole-genome analyses were used to investigate the association between molecular tumor profiles, pathogenesis and prognosis. A total of 85 periampullary adenocarcinomas were characterized by mRNA and miRNA expressions profiling. Molecular profiles of the tumors from the different anatomical sites of origin as well as of the different histological subtypes were compared. Differentially expressed mRNAs and miRNAs between the two histopathological subtypes were linked to specific molecular pathways. Six miRNA families were downregulated and four were upregulated in the pancreatobiliary type as compared to the intestinal type (P < 0.05). miRNAs and mRNAs associated with improved overall and recurrence free survival for the two histopathological subtypes were identified. For the pancreatobiliary type the genes ATM, PTEN, RB1 and the miRNAs miR-592 and miR-497, and for the intestinal type the genes PDPK1, PIK3R2, G6PC and the miRNAs miR-127-3p, miR-377* were linked to enriched pathways and identified as prognostic markers. The molecular signatures identified may in the future guide the clinicians in the therapeutic decision making to an individualized treatment, if confirmed in other larger datasets.

The effects of age, seropositivity and disease duration on autonomic cardiovascular reflexes in patients with rheumatoid arthritis

Previous studies have shown that autonomic cardiovascular reflexes (ACRs) are impaired in rheumatoid arthritis (RA) and in old age. To investigate the integrity of ACRs in patients with RA, with reference to age, duration of disease and rheumatoid factor (RF) positivity, we conducted a prospective open study of 62 RA outpatients (age 38-84) and 41 healthy controls (age 22-82) using five standard tests of ACR function. Patients of all ages with RA were found to have blunted ACRs when compared with younger controls, though this effect was subclinical. Older RA patients did not have significantly more ACR impairment than older controls. There was a tendency to greater impairment of ACRs in RA patients with a positive RF. The age-associated changes in ACRs in normal subjects are similar to those seen in RA patients of all ages. The effects of RA and age on ACRs do not appear to be additive.

SERCA pump isoform expression in endothelium of veins and arteries: every endothelium is not the same

Endothelium from rat aorta expresses sarco/endoplasmic reticulum Ca2+(SERCA) pump gene SERCA3 where as the smooth muscle expresses SERCA2. This has led to the postulate that vascular endothelium expresses SERCA3. To test this postulate, we examined the SERCA2 and SERCA3 mRNA expression in endothelium and smooth muscle dissected from coronary artery, coronary vein, aorta and vena cava of pig. Smooth muscle from all arteries and veins expressed only the SERCA2 mRNA. Endothelium from coronary artery, coronary vein and aorta expressed both SERCA2 and SERCA3 mRNA but the endothelium from vena cava did not express SERCA3 mRNA although it expressed SERCA2. These observations support the postulate that vascular endothelium expresses SERCA3 but the affirmation is equivocal because vena cava endothelium does not express SERCA3.

Effects of peroxide on the fluorescence of the Ca2+ probe Fluo 3 and the pH probe BCECF

Fluorescence probes are invaluable tools in monitoring intracellular ion concentrations. They have also been used for studying how reactive oxygen species alter these concentrations and yet there are no studies indicating how reactive oxygen species directly affect the characteristics of the probes. Our concern was that if reactive oxygen were to affect characteristics of these probes, these measurements would be inconsequential. Therefore, we examined the effects of peroxide on the Ca2+-sensitive dye Fluo 3 and the pH sensitive dye BCECF. Peroxide concentrations below 10 mM did not alter fluorescence or binding characteristics of either dye. Since the concentrations of peroxide used in most pathophysiological experiments are in the micromolar range, we conclude that these probes are appropriate for monitoring the effects of peroxide on intracellular ion concentrations.