Controlled-Release Hydrogel Microspheres to Deliver Multipotent Stem Cells for Treatment of Knee Osteoarthritis

Osteoarthritis (OA) is the most common form of joint disease affecting articular cartilage and peri-articular tissues. Traditional treatments are insufficient, as they are aimed at mitigating symptoms. Multipotent Stromal Cell (MSC) therapy has been proposed as a treatment capable of both preventing cartilage destruction and treating symptoms. While many studies have investigated MSCs for treating OA, therapeutic success is often inconsistent due to low MSC viability and retention in the joint. To address this, biomaterial-assisted delivery is of interest, particularly hydrogel microspheres, which can be easily injected into the joint. Microspheres composed of hyaluronic acid (HA) were created as MSC delivery vehicles. Microrheology measurements indicated that the microspheres had structural integrity alongside sufficient permeability. Additionally, encapsulated MSC viability was found to be above 70% over one week in culture. Gene expression analysis of MSC-identifying markers showed no change in CD29 levels, increased expression of CD44, and decreased expression of CD90 after one week of encapsulation. Analysis of chondrogenic markers showed increased expressions of aggrecan (ACAN) and SRY-box transcription factor 9 (SOX9), and decreased expression of osteogenic markers, runt-related transcription factor 2 (RUNX2), and alkaline phosphatase (ALPL). In vivo analysis revealed that HA microspheres remained in the joint for up to 6 weeks. Rats that had undergone destabilization of the medial meniscus and had overt OA were treated with empty HA microspheres, MSC-laden microspheres, MSCs alone, or a control vehicle. Pain measurements taken before and after the treatment illustrated temporarily decreased pain in groups treated with encapsulated cells. Finally, the histopathological scoring of each group illustrated significantly less OA damage in those treated with encapsulated cells compared to controls. Overall, these studies demonstrate the potential of using HA-based hydrogel microspheres to enhance the therapeutic efficacy of MSCs in treating OA.

Hospital-based violence prevention programmes in South Wales Emergency Departments: A process evaluation protocol

BACKGROUND

Addressing violence related harm is a global public health priority. While violence is primarily managed in the criminal justice system, healthcare supports and manages those injured by violence. Emergency Departments (EDs), the primary destination for those seriously injured, have emerged as a candidate location for violence prevention initiatives. There is limited evaluation of ED-based violence prevention, and a lack of guidance for the implementation and delivery of them. Nurse-led Violence Prevention Teams (VPTs) have been developed and implemented in two EDs in Wales, UK. This protocol describes methods used in the process evaluation of these VPTs.

AIM

To understand how VPTs function, how they were implemented, and mechanisms of impact, as well as the exploration of wider contextual factors influencing their function.

METHODS

Adopting a critical realist approach and informed by the Medical Research Council (MRC) guidance for process evaluations, the process evaluation will employ qualitative methods to collect and analyse data: a scoping review of evidence of effectiveness that considers the causal mechanisms underpinning violence; a documentary analysis to determine operational considerations concerning the development, implementation and delivery of the VPTs; a descriptive analysis of routine ED data to characterise the prevalence of violence-related attendances in each ED; interviews with professional stakeholders (N = 60) from the violence prevention ecologies in which the VPTs are embedded.

DISCUSSION

This protocol outlines a process evaluation of a novel, nurse led violence prevention intervention. Findings will be used to inform policy makers' decision making on whether and how VPTs should be used in practice in other EDs across the UK, and the extent that a single operational model should be adjusted to address the local characteristic of violence. To the authors knowledge, this is the first process evaluation of a UK-based, nurse led Emergency Department Violence Prevention Team.

TRIAL REGISTRATION

Protocol registration ISRCTN: 15286575. Registered 13th March, 2023.

A10 OVEREXPRESSION OF ASCL2 ALTERS DIFFERENTIATION, CELL CYCLE AND RESISTANCE TO ANTI-CANCER TREATMENT IN ESOPHAGEAL ORGANOIDS

Background

The esophagus is in constant contact with the austere environment caused by food and gastric reflux. It is protected by a squamous epithelium which maintenance is provided by a rare subpopulation of basal cells: Keratin 15+ (Krt15+) stem cells. However, little is known about the mechanisms underlying the expansion and the function of these stem cells. It was shown that the transcription factor ASCL2 is strongly upregulated in Krt15+ cells compared to Krt15- cells. Interestingly, ASCL2 is a gene target of the Wnt/β-catenin pathway, which acts as a regulator of proliferation and maintenance of the stemness state.

Purpose

The ultimate goal of my research project is to determine the role of ASCL2 in the maintenance of esophageal stem cells. To do so, I will investigate the role of ASCL2 in esophageal epithelial biology.

Method

Lentiviral infection approach was used to obtain mouse esophageal organoids overexpressing ASCL2 (ASCL2^OE). Organoid culture, immunostaining (such as IF and H&E), qPCR, WB, mass spectrometry and proliferation assay were used to characterize the effect of ASCL2^OE on morphology, differentiation, proliferation, self-renewal, and gene expression.

Result(s)

ASCL2^OE severely altered the morphology of organoids, which were smaller and less differentiated. Defects in differentiation was investigated by IF which showed that some cells expressed both p63 and K13, respectively basal and suprabasal markers. Thus, cells seem to be blocked in an intermediate state of differentiation suggesting a default in cell fate decision. Mass spectrometry analysis confirmed a change in biological processes related to differentiation of keratinocytes and of epithelial cells. We also investigated the role of ASCL2 in self-renewal and observed that organoid formation rate (OFR) was reduced in ASCL2^OE organoids. Furthermore, proliferation was also reduced in WST-1 and EdU assays. We then observed significant changes in the cell cycle by flow cytometry: there is an increased in the number of cells in G0/G1 and a major decrease in G2/M cells, suggesting a blockade in G1. Interestingly, CDNK2a (p16INK4a), an inhibitor of cell cycle progression, was increased in our mass spectrometry results. Finally, ASCL2 could also play a role in radio and chemoresistance of Krt15+ stem cells, as ASCL2^OE organoids are less sensitive to radiation and chemotherapy agents than control.

Conclusion(s)

ASCL2 could play a role in orchestrating cell fate decision in the esophageal epithelium as ASCL2^OE organoids showed alteration in differentiation, proliferation, and cell cycle.

Please acknowledge all funding agencies by checking the applicable boxes below

Other

Please indicate your source of funding;

NSERC, Canada Research Chairs and CRCHUS scolarship

Disclosure of Interest

None Declared

Left ventricular morphology in patients with aortic coarctation and bicuspid aortic valve: novel insights from a statistical shape modelling framework

Background

The functional implications of left ventricular (LV) morphological characterization in congenital heart disease (CHD) are not widely explored.

Purpose

This study qualitatively and quantitatively assessed LV shape associations with a) LV function and b) thoracic aortic morphology in patients with aortic coarctation (CoA) with/without bicuspid aortic valve (BAV).

Methods

A statistical shape modelling (SSM) framework was employed to analyse three-dimensional (3D) LV shapes from cardiac magnetic resonance (CMR) imaging data in n=110 cases including: isolated CoA (n=25), CoA+BAV (n=30), isolated BAV (n=30), and age-matched healthy controls (n=25). Average 3D templates (Picture 1) and deformations were computed. Correlations between shape data and CMR-derived morphometric parameters (i.e. sphericity, conicity) as well as CMR-derived global and apical strain values were assessed to elucidate possible functional implications. The relationship between LV shape features and arch architecture (i.e. gothicity, tortuosity) was also explored by means of regression analysis.

Results

The LV template was shorter and more spherical in CoA patient (Picture 1), as also confirmed by statistical analysis of the SSM-derived shape modes. LV sphericity, which was higher in CoA, was associated (p≤0.04) with lower global longitudinal, radial and circumferential strain, irrespective of the presence of aortic stenosis and/or regurgitation. Conversely, neither LV morphology nor LV strain was not associated with arch architecture.

Conclusions

Differences in LV morphology were observed between CoA and BAV patients. Increasing LV sphericity was associated with reduced strain, independent of aortic arch architecture and functional aortic valve disease.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation and NIHR BRC

O-135 Sperm-borne small ribonucleic acid profile significantly impacts embryo development

Study question

Do normozoospermic males with reduced pre-implantation embryo development have aberrant sperm small RNA profiles?

Summary answer

Small RNA sequencing suggests the small RNA profile may differ in normozoospermic males with low blastocyst development rates, compared to males with higher blastocyst progression.

What is known already

Current male factor infertility diagnostics are insufficient, with 30-50% of subfertile males having unknown etiology. Spermatozoa contain a complex, epigenetically-marked genome and a collection of RNAs and proteins, which are not adequately assessed by current diagnostic methods. The sperm small RNA payload is reportedly modified during epididymal transit and in response to paternal exposures, influencing which sperm small RNA species are delivered to the oocyte. Mechanistic animal studies and correlative human and animal studies have suggested that sperm small RNAs may be important for early embryonic development and health of offspring, though their diagnostic and therapeutic value are still unclear.

Study design, size, duration

Human semen samples were collected between April 2017 and August 2020 from a total of 56 male patients presenting to CReATe Fertility Centre for fertility evaluation. Clinical data was accessed retrospectively. All patients were normozoospermic, according to standard semen analysis and were using donor oocytes. Samples were divided into high (n = 20), average (n = 16), and low (n = 20) fertility groups based on their deviation (1 standard deviation) from the mean blastocyst rate.

Participants/materials, setting, methods

Semen analysis was undertaken immediately following sample collection and spermatozoa were isolated by centrifugation. Sperm small RNA was purified and eluted using the RNeasy and MiRNeasy Kits (Qiagen). Barcoded and amplified cDNA libraries were prepared from small RNA using the NEXTFLEX Small RNA-Seq Kit v3 (Bioo Scientific). Resulting libraries were pooled, size-selected to a range of 140-190 base pairs, denatured and diluted for sequencing. Single-end, 75 bp sequencing was performed using the NextSeq 550 (Illumina).

Main results and the role of chance

Sequencing generated approximately 300 million raw reads, with 30 samples exceeding 2 million reads included in the differential expression analysis. Most reads were mapped to rRNAs (69%), miRNAs (11%), and piRNAs (12%). However, transfer RNA fragments from tRNA-Gly-GCC and tRNA-Val-CAC were the most abundant sequences. Top annotated miRNAs include: miR-12136-5p; miR-21-5p; and miR-122-5p. Principal component analysis revealed 222 genes that were differentially expressed between the high (n = 14) and low (n = 11) fertility groups (p < 0.05). Interestingly, the top 50 differentially expressed sRNAs are sufficient to effectively cluster sperm with poor blastocyst development rates.

Limitations, reasons for caution

The results are limited by a relatively low sequencing depth (mean of 4.1 million reads per sample) and sample size. Fertility groups were determined by blastocyst rates, which can be confounded by non-sperm-derived variables, including technical skill, embryo culturing conditions, and maternal factors (though donor oocytes were used).  

Wider implications of the findings

With additional validation, a clinically-useful panel of differentially expressed sperm small RNAs could be used to predict IVF success and evaluate therapies aimed at improving male reproductive health. Augmenting traditional semen analytics with diagnostic sperm small RNA analysis could reduce time to pregnancy and the psychosocial impacts of fertility treatment.

Trial registration number

Not applicable

A21 OVEREXPRESSION OF ASCL2 ALTERS DIFFERENTIATION IN ESOPHAGEAL ORGANOIDS

Background

The first population of stem cells in the esophageal epithelium was recently identified with the marker Keratin 15 ( Krt15). However, little is known about the mechanisms underlying the expansion and the function of these stem cells. It was shown that the transcription factor ASCL2 is upregulated in Krt15+ cells compared to Krt15- cells. Interestingly, ASCL2 is a gene target of the Wnt/β-catenin pathway, which acts as a regulator of proliferation and maintenance of the stemness state. The ultimate goal of my research project is to determine the role of ASCL2 in the maintenance of esophageal stem cells and to identify its binding partners.

Aims

Investigate the role of ASCL2 in esophageal epithelial biology.

Methods

Lentiviral infection approach was used to obtain mouse esophageal organoids overexpressing ASCL2. Organoid culture, immunostaining (such as IF and H&E), qPCR, WB and proliferation assay were used to characterize the effect of ASCL2 overexpression on morphology, differentiation, proliferation, self-renewal and gene expression.

Results

First, ASCL2 overexpression was confirmed by WB. Interestingly, the morphology of organoid overexpressing ASCL2 was severely altered: organoids were smaller and less differentiated. Defect in differentiation was investigated by qPCR and IF using relevant markers such as p63, Krt13, Wnt5a and NT5E. Indeed, we observed an increase in basal marker ( p63), a decrease in suprabasal markers ( Krt13, Wnt5a) and in a stem cell marker ( NT5E). We also investigated the role of ASCL2 in self-renewal and observed that organoid formation capacity was reduced in ASCL2-overexpressing organoids. Furthermore, proliferation was also reduced in WST-1 assays. We also observed lower expression of the gene Top2a, a recently identified marker of the proliferative basal cell population in the human esophagus. Finally, we observed significant changes in the expression of genes associated with quiescent stem cells (Clu, ZFP36L2 and Anxa1).

Conclusions

ASCL2 overexpression alters differentiation and proliferation in organoids. ASCL2 could play a role in orchestrating cell fate decision in the esophageal epithelium.

Funding Agencies

NSERC, Canada Research Chair

Social inclusion, intersectionality, and profiles of vulnerable groups of young people seeking mental health support

BACKGROUND

headspace centres provide enhanced primary mental healthcare for young people. A priority is to provide services for all young people irrespective of a range of social disadvantages or social exclusion. The aims of this study were to: (i) delineate extent of social inclusion across domains of housing, studying/employment, functioning, alcohol, and other drug use; and (ii) map profiles of young people deemed vulnerable to experiencing additional barriers to accessing services based on their social inclusion domains (e.g., those living in unstable housing, not in employment/education, and/or experiencing intersecting or multiple forms of disadvantage or difficulties), including detailing their clinical characteristics.

METHODS

Young people were recruited from five headspace centres. Data relevant to social inclusion were examined. Multivariate logistic regression models were used to determine overlap between vulnerable groups, functional, social, clinical, and behavioural factors.

RESULTS

1107 young people participated, aged 12-25 years (M = 18.1 years, SD = 3.3), most living in stable housing (96.5%) and engaged in studying/employment (84.8%). Specific vulnerabilities were evident in young people with NEET status (15.2%); in unstable accommodation (3.5%); of culturally diverse backgrounds (CALD) (12.2%); living in regional areas (36.1%); and identifying as lesbian, gay, bisexual, transgender, intersex, queer/questioning, and asexual plus (LGBTIQA+; 28.2%). Higher levels of distress, substance use, functional impairment, and lower social support were reported by those who were NEET and/or in unstable housing. LGBTIQA+ status was associated with high distress, depressive symptoms, and suicidal ideation.

CONCLUSIONS

Most participants reported good social support, stable housing, and engagement in work or education. Those deemed vulnerable were likely to experience social exclusion across multiple domains and reported more mental health problems. The co-occurrence of mental ill-health and social exclusion highlights the importance of integrated mental healthcare.

Surgical management of superficial digital flexor tendon luxation in dogs: 48 cases (2005-2020)

OBJECTIVES

To report the outcome, frequency of complications and potential prognostic factors associated with surgical repair of superficial digital flexor tendon (SDFT) luxation in dogs.

MATERIALS AND METHODS

Medical records from 10 referral hospitals were reviewed retrospectively for cases of SDFT luxation in dogs that underwent surgical stabilisation. Signalment, clinical presentation, diagnostic imaging, surgical method, type and length of post-operative limb immobilisation, nature of and length of exercise restriction, presence of post-operative complications and outcomes were recorded. Data were summarised descriptively and prognostic risk factors assessed for association with surgical outcome using risk ratios.

RESULTS

Forty-eight cases were included. A successful surgical outcome was recorded in 35 of 48 (73%) cases. Re-luxation of the SDFT occurred in seven of 48 (15%). Six out of 48 (13%) had a persistent lameness despite a stable non-luxating SDFT. A high frequency of post-operative complications occurred (71%), with the majority resolved medically. The risk of surgical failure was 60% higher (risk ratio 1.6, 95% confidence interval 1.1 to 2.4) where absorbable suture material was used compared to non-absorbable suture material. Surgical failure was more common in cases managed with non-rigid immobilisation post-operatively (57% failure) compared to cases managed with rigid immobilisation (19% failure), although this result was not statistically significant. Limb immobilisation of 6 weeks or longer did not significantly affect surgical outcome, compared to shorter periods of exercise restriction or limb immobilisation.

CLINICAL SIGNIFICANCE

A good outcome can be expected following surgical stabilisation of SDFT luxation. The use of non-absorbable suture was associated with a more successful surgical outcome.

The psychometric characteristics of the Kessler Psychological Distress Scale (K6) in help-seeking youth: What do you miss when using it as an outcome measure?

This is the first study to describe psychometric properties of the Kessler Psychological Distress Scale (K6) in a large cohort of help-seeking young people presenting to primary mental health care services. The aim was to determine whether the K6 was appropriate for monitoring outcomes in such settings. 1067 young people were recruited from Australian headspace services. We examined dimensionality of the K6, measurement invariance, and how the K6 correlated with the the Patient Health Questionnaire-9 (PHQ-9)and the Generalised Anxiety Disorder-7 Scale (GAD-7). Standardised Response Mean (SRM) and Cohen's d effect size (ES) were used to examine 3-month stability of the K6. The best-fitting model was a two-factor model: (i) nervous and restlessness; and (ii) hopeless, worthless, depressed and effort. Measurement non-invariance was observed for sex and age groups. K6 strongly correlated with the PHQ-9 and GAD-7. The K6 was less sensitive to change compared to these other two measures. There was some support for the K6 being a screener for young people presenting to primary care; however, there issues arise with its use as an outcome measure. These issues include measurement non-invariance, concern about the dimensionality and focus of items, and its sensitivity to change.