P-P36 AXIOS™ stents in the management of pancreatic fluid collections: case series from a single healthcare trust

Background

This was a consecutive case-series of all pancreatic fluid collections (PFCs) managed with AXIOS™ stents in a 3 year period from a single healthcare trust, retrospectively analysed to determine the rate of technical success, clinical success and adverse events related to the procedure.

Methods

All patients in who underwent AXIOS stenting for PFCs in the Belfast Health and Social Care Trust between May 2016 and July 2019  were included, with a follow-up period of 1 year. Electronic care records (ECR) and Radiology reports were reviewed for each patient. PFCs were categorised into walled-of pancreatic necrosis (WOPN) and pseudocysts as per the revised Atlanta classification. The number of repeat procedures, endoscopic lavage +/- necrosectomy, the need for definitive surgery or any adverse events post-procedure were recorded.

Results

45 patients were included in the study (21 male, 24 female). 17 patients (37.8 %) had WOPN and 28 (62.2 %) pancreatic pseudocysts. Median collection diameter on CT imaging was 12 cm (range 6.2 – 22 cm).

The procedure was technically successful in 43 patients (95.6%), with stent mal-deployment in the remaining 2. Median duration for stenting was 29.5 days (Range 13 – 92).

The procedure was clinically successful for 33 patients (73.3%). n = 8 (17.8%) of patients were re-admitted with sepsis following stent insertion requiring intravenous antibiotics. n = 16 (35.6%) patients required repeated endoscopic lavage +/- necrosectomy following stent blockage (n = 11 WOPN, n = 5 pseudocyst). n = 2 (4.4%) stents accidentally dislodged during lavage necessitating surgical removal. n = 4 (8.9%) patients required a second AXIOS stent within 45 days of removal, n = 2 (4.4%) required CT guided drainage and n = 8 (17.8%) ultimately required surgical intervention.The rate of adverse events post-procedure was 33.3%.

Conclusions

AXIOS stenting appears to be effective first-line in the “step-up” approach to managing PFCs. Despite some drawbacks, our study showed they were technically successful in 95.6% and clinically successful in 73.3% of cases, requiring no further intervention. For PFCs that do require surgery, AXIOS stenting may allow for a period of patient optimisation prior to definitive treatment.

P-L16 The Impact of Covid-19 on the Management of Primary and Metastatic Liver Cancers; A Single Centre Experience

Background

The Covid-19 pandemic has impacted on all aspects of health care. Surgical specialties have been affected by the impact on theatre time and space, staff re-deployments, reduced ICU capacity for non-Covid patients, and in some cases this has had a significant impact on wait time for surgery and overall surgical capacity. In our tertiary referral HPB unit, the service has been relocated to two different sites throughout the pandemic. We aimed to assess the impact of this on patients undergoing liver resection

Methods

We examined patient data for all patients undergoing liver resection in the 15 month period prior to the introduction of national lockdown, and compared this with all patients who have undergone liver resection since. We looked at total number of cases, ICU admission rates (planned vs unplanned), length of stay, case mix, histology, rates of laparoscopic vs open surgery, and length of time from completing neoadjuvant chemotherapy to surgery. Data were obtained from electronic care records and patient notes.

Results

The overall number of cases was similar (84 pre-covid vs 86 since) and basic patient demographics were unaffected. Median length of stay was the same for both groups (7 days). Colorectal metastases were the underlying pathology in the majority of cases (56/84 pre Covid, 56/86 post). Numbers of laparoscopic and laparoscopic converted to open cases were reduced in the post-Covid era, 12 prior versus four since. The median time from completion of neo-adjuvant chemotherapy to surgery was also affected, increasing from 46 to 62 days.

Conclusions

These data show some differences in patient care in the pre and post-Covid eras, in particular a lower rate of laparoscopic surgery and longer period of time between neo-adjuvant treatment and surgery. Longer follow up is required to see if these trends persist and their effect on long term survival and recurrence rates. However, despite the strains on the system there were similar numbers of patients pre and post Covid, indicating that patients are still presenting and being treated. This showed that staff responded well to the pressures of Covid, and trainee experience would have been similar

Realizing topologically ordered states on a quantum processor

[Figure: see text].

206 EXPLORING THE RELATIONSHIP BETWEEN LONELINESS, FRAILTY, AND HEALTHCARE UTILISATION IN IRELAND’S OLDER ADULTS DURING THE COVID-19 PANDEMIC

Background

The COVID-19 pandemic has disproportionately affected older adults, both in morbidity and mortality¹. The effects of the pandemic go beyond contracting the SARS-CoV-2 virus, leading to devastating consequences, particularly for individuals over the age of 60. In Ireland, isolation in older adults was exacerbated by cocooning measures and geographical limitations. The purpose of this study was to explore the relationship between loneliness, frailty, and the utilisation of health services in a sample of sexagenarians in Ireland.

Methods

Adults aged 60–70 attending COVID-19 vaccine appointments at a Level 3 Hospital in Ireland (n = 75) were invited to participate in a 36-item questionnaire. Participants reported demographic information and questions regarding physical well-being, healthcare utilisation, lifestyle and behaviours, and impact of vaccination. The survey also included three validated questionnaires: PRISMA-7 for frailty, SARC-F for sarcopenia, and the UCLA 3-Item Loneliness Scale (UCLA-3ILS).

Results

Of the 75 survey respondents, the mean age was 63.2. 72% (n = 54) identified as female. 28% (n = 21) reported that they had been cocooning during the past year. While 84% (n = 63) of respondents reported that they cancelled routine medical appointments during the pandemic, none reported avoiding attending hospital. Five respondents met the criteria for frailty and four were identified as probable sarcopenic. There was no significant difference (p = 0.64) in mean scores on the UCLA 3-ILS between frail and non-frail individuals. Persons identified as sarcopenic were more likely to have higher scores on the UCLA-3ILS (p = 0.0005).

Conclusion

This research highlights the multifaceted relationship between frailty, loneliness, and healthcare utilisation among Irish adults ages 60–70 during the COVID-19 pandemic. Future research in program, policy, and intervention development for at-risk older adults, particularly those who are frail, sarcopenic, and/or lonely, can work to reduce associated negative outcomes.

Reference

1. Kang S-J and Jung, SI. (2020). Age-Related Morbidity and Mortality among Patients with COVID-19. Infect Chemother., 52(2): 154–164.

Impact of SARS-CoV-2 pandemic on pancreatic cancer services and treatment pathways: United Kingdom experience

INTRODUCTION

The SARS-CoV-2 pandemic presented healthcare providers with an extreme challenge to provide cancer services. The impact upon the diagnostic and treatment capacity to treat pancreatic cancer is unclear. This study aimed to identify national variation in treatment pathways during the pandemic.

METHODS

A survey was distributed to all United Kingdom pancreatic specialist centres, to assess diagnostic, therapeutic and interventional services availability, and alterations in treatment pathways. A repeating methodology enabled assessment over time as the pandemic evolved.

RESULTS

Responses were received from all 29 centres. Over the first six weeks of the pandemic, less than a quarter of centres had normal availability of diagnostic pathways and a fifth of centres had no capacity whatsoever to undertake surgery. As the pandemic progressed services have gradually improved though most centres remain constrained to some degree. One third of centres changed their standard resectable pathway from surgery-first to neoadjuvant chemotherapy. Elderly patients, and those with COPD were less likely to be offered treatment during the pandemic.

CONCLUSION

The COVID-19 pandemic has affected the capacity of the NHS to provide diagnostic and staging investigations for pancreatic cancer. The impact of revised treatment pathways has yet to be realised.

Morphological and p40 immunohistochemical analysis of squamous differentiation in endoscopic ultrasound guided fine needle biopsies of pancreatic ductal adenocarcinoma

The basal-like molecular subtype of pancreatic ductal adenocarcinoma (PDAC) is associated with poor prognosis and upregulation in TP63ΔN (p40) network. Adenosquamous histology can be observed. This study assessed immunohistochemical p40 expression in fine needle biopsy (FNB) samples with PDAC and association with cytomorphological features of squamous differentiation and clinical data. 106 EUS FNBs with PDAC were assessed for eight cytomorphological features of squamous differentiation. P40 H-score (intensity 0-3 × percentage positive nuclei) was analysed for association with morphological features, patient age, gender, operability, chemotherapy and survival. P40 H-score in 14 paired FNBs and resections was compared. P40 h-score was 1-3 in 31%, 4-30 in 16% and > 30 in 13% of FNBs. It was significantly associated with intercellular bridges, elongated cell shape, sharp cell borders, angular nuclei with homogenous chromatin (p < 0.001) and dense cytoplasm (p = 0.002). Keratinisation was not seen. Inoperable patients (n = 81) had a shorter median survival for h-score > 30 (n = 9, 1.8 months) than for h-score ≤ 30 (n = 66, 6.7 months) not quite reaching statistical significance (p = 0.08). P40 was significantly associated with squamous morphology in FNBs with PDAC. P40 H-score > 30 showed a trend towards shorter survival in inoperable patients. Squamous differentiation may be a treatment target in PDAC.

TP6.1.6 The management of pancreatic fluid collections with AXIOS stenting in Belfast HSCT

Aims

To assess the viability of using lumen-apposing self-expandable AXIOS stents, inserted under endoscopic ultrasound guidance, in the management of pancreatic fluid collections (PFCs) within the Belfast Health and Social Care Trust.

Methods

Data for all AXIOS stents inserted endoscopically between May 2016 and July 2019 were included. Electronic care records (ECR) and Radiology reports were reviewed for each patient. PFCs were categorised into walled-of pancreatic necrosis (WOPN) and pseudocysts, and the number of repeat procedures, OGDs with lavage, or the need for definitive surgery were recorded. The timeframe to surgery and whether PFCs recollected was also noted.

Results

45 AXIOS stents were inserted for PFCs in the audit period. n = 17 (37.8%) were for WOPN, n = 28 (62.2%) for pseudocysts. Mean duration of stenting was 38 ± 19.7 days. n = 11 (35.6%) patients were readmitted for sepsis with stent in situ, and n = 16 (35.6%) required OGD and lavage for stent blockage (n = 11 WOPN; n = 5 pseudocyst). n = 2 (4.4%) stents accidentally dislodged during lavage necessitating surgical removal. n = 4 (8.9%) patients required a second AXIOS stent following removal, n = 2 (4.4%) required CT guided drainage and n = 8 (17.8%) ultimately required surgical intervention.

Conclusions

Despite some drawbacks, including the need for intermittent OGD and lavage to maintain patency, AXIOS stenting appears to be effective first-line management for PFCs. Our audit showed they were successful in 71% of cases, requiring no further intervention. In PFCs that do require surgical management, AXIOS stenting may represent an effective bridge to surgery allowing for patient optimization before definitive care.

1174 The Reporting of Centre and Surgeon Experience in Studies of Robot Assisted Cholecystectomy: A Systematic Review

Introduction

Over 90% of cholecystectomies are performed using minimally invasive techniques. Robotic cholecystectomy (RC) has been developed to overcome technical limitations of laparoscopy, including improved range of movement and visualisation. Despite becoming increasingly widespread, the safety and efficacy of RC remain unestablished. This review aims to analyse the quality assurance reporting through centre and surgeon expertise in RC.

Method

A systematic search was conducted to identify all published studies reporting RC. Data on quality assurance measures were collected, including: centres involved, surgeons’ experience and training.

Results

Of the 1425 abstracts screened, 90 full-text papers were included. Sixty-four studies (71%) were single institutions. Of the thirty studies (33%) reporting centre type, 28 were conducted in specialist/regional/tertiary centres. Only four stated their caseload of RC. No studies described pre-specified criteria or minimum experience required for a surgeon to participate. Fifty-two (58%) reported the number of surgeons operating and 13 (14%) stated surgeons’ training grade. Two quantified previous RC experience, 7 stated prior laparoscopic experience. Only 21 (23%) described training prior to the surgeons’ first in-human procedure; animal based (n = 12), simulation (n = 12), observation (n = 4), lab-based (n = 3). Specific mentorship was reported in 8 studies, and 13 described dual operating.

Conclusions

Little information was provided about the experience and training of operating surgeons, making it difficult to ascertain whether replicable techniques were utilised which would allow development of a learning curve. This highlights the need for better transparency when reporting surgical innovation, to ensure the safe, evidence-based adoption of new technologies into clinical practice.

692 A Machine Learning Approach to Predict the Postoperative Length of Stay After Coronary Artery Bypass Grafting Using Preoperative Characteristics

Aim

Lengthy hospital length of stay (LOS) has a direct impact on healthcare costs. We aimed to design predictive models of prolonged LOS after coronary artery bypass grafting (CABG) with only preoperative characteristics and machine learning (ML) strategies.

Method

In a single centre retrospective analysis, 2,082 consecutive patients underwent first-time elective/urgent CABG: 1,262 has a short postoperative LOS (≤ 6 days) while the remaining 820 had a long LOS (&gt; 6 days). 70/30 training/testing ratio and resampling methods were used, and cross-validation was conducted.

Results

The two groups differ significantly in terms of pre-operative variables: short LOS patients were younger (p &lt; 0.01), more frequently male (p &lt; 0.01) with lower BMI (p &lt; 0.01) and better angina class (p &lt; 0.01) and NYHA class (p &lt; 0.01). Moreover, they had lower incidence of hypertension (p = 0.04), COPD (p &lt; 0.01) and PVD (p &lt; 0.01). The Logistic Euroscore was also better in this group (median 0.02 vs 0.03, p &lt; 0.01). The predictive abilities of the ML models were as follows: logistic regression: Area under the Curve (AUC) = 0.71, accuracy = 0.69; Generalized additive model: AUC= 0.7, Accuracy = 0.68; Random Decision Forest: AUC = 0.7, Accuracy = 0.68; Naïve Bayes AUC = 0.63, Accuracy 0.58.

Conclusions

Developing a reliable predictive model with only pre-operative variables proved to be difficult, but several preoperative characteristics have a significant impact on the probability of prolonged LOS after CABG. Larger studies are needed to investigate the possibility of developing a reliable predictive model that would help to improve surgical planning.

1024 The Use of the Pedicled Anterolateral Thigh (ALT) Flap for the Reconstruction of Abdominal Wall Defects in High-Risk Patients: A Case Series and Systematic Review

Introduction

The pedicled anterolateral thigh (ALT) flap is considered as a suitable option in complex abdominal wall reconstruction. Its use as a reconstructive option is infrequent in the literature, and to date, there has been no systematic review evaluating its long-term outcomes. We report our experience with the pedicled anterolateral thigh flap for abdominal wall reconstruction in high-risk patients.

Method

A prospective database was created for patients with abdominal wall defects treated with pedicled ALT with extended fascia lata flaps between 2014 and 2017. Patient demographics, aetiology, size, location of defect and post-operative results were reviewed. Abdominal defects were classified into the following zones: 1A, upper midline; 1B, lower midline; 2, upper quadrant; 3, lower quadrant. A systematic review of the literature was conducted using PUBMED and EMBASE.

Results

4 patients (mean age 59.5 years, range 50-65 years) underwent reconstruction with pedicled ALT flaps. 3 flaps developed partial necrosis secondary to infection; 1 flap required surgical debridement, and 2 were managed conservatively. There was one flap failure, due to avulsion of the pedicle during inset. At mean follow up of 2.75 years (range 1 to 4 years) 3 patients have clinical bulging or herniation.

Conclusions

Review of the literature demonstrated 52 patients from 17 case series or reports. The overall infection and partial flap loss rates were both 6%. There were no reported flap failures. Our study demonstrates that the pedicled anterolateral thigh flap is an effective flap option for the repair of large defects of the abdominal wall in high-risk patients.

1158 Summarising the Reporting of Study Outcomes in Robotic Oesophagectomy: A Systematic Review

Introduction

There is an increasing adoption of robotic oesophagectomy in place of standard techniques for oesophageal cancer resection. This is potentially due to its perceived technical benefits and improved short-term outcomes. Consistency in outcome selection, definition and reporting between studies is required for effective evidence synthesis and prevention of research waste. The aim of this review is to perform an in-depth analysis of outcome reporting in robotic oesophagectomy.

Method

Systematic searches were conducted using key words for robotic surgery and oesophageal cancer, from inception to February 2020. Studies reporting any outcome for robotic oesophagectomy were included. Outcomes in each study were recorded verbatim and categorised into twelve domains. Outcomes were independently categorised by two reviewers. Where reported, the follow-up period was also recorded.

Results

Of 954 abstracts screened, 226 full texts were reviewed and 102 included. Only one study was a RCT. A total of 1422 outcomes were reported. Each study had a median of 14 reported outcomes (range 1-25). Outcomes related to complications (n = 578, 99 studies), technical/operative factors (n = 290, 90 studies), and pathology (e.g., resection margin) (n = 197, 83 studies) were reported most frequently. No single outcome, or outcome domain was reported in all studies. No studies used a core outcome set for reporting. Forty-five studies stated a follow-up period, ranging from &lt;1 month to 58 months.

Conclusions

There is significant heterogeneity in the selection and reporting of outcomes in robotic oesophagectomy. This calls for the use of a core outcome set to allow standardisation and transparency of outcome reporting.

Change in opioid and analgesic use for headaches after aneurysmal subarachnoid hemorrhage over time

BACKGROUND

Severe headache, a hallmark of aneurysmal subarachnoid hemorrhage (aSAH), affects up to 90% of patients during hospitalization. Opioids remain the guideline recommended mainstay of acute therapy despite their significant side effects and potential for tolerance and addiction. We evaluated time trends in opioid prescriptions, hypothesizing a decline with increasing recognition of the opioid crisis.

METHODS

We performed a retrospective review of patients with aSAH admitted to a single tertiary care center between 2012 and 2019 and included patients with Hunt-Hess-Grade≤3 who were able to verbalize pain scores. Collected variables included mean and maximum daily headache scores, aneurysm treatment modality, and daily analgesic medication doses.

RESULTS

Of 340 patients with aSAH, 114 (86 from 2012-2016 and 28 from 2017-2019) were included. Of the included patients, 86/114 (75.4%) were female. Patients in the 2012-2016 had a median age of 55 compared to 63 in the 2017-2019 group (P=0.02). Otherwise, there was no significant difference in demographic data including time in hospital, treatment option utilized, or aneurysm characteristics. Maximal daily headache score ranged from 6 to 8 for 2012-2016 and 5 to 8 for 2017-2019 cohorts. Average oral morphine equivalents (in mg) administered during hospitalization were similar between groups (2012-2016: 251±345 95% CI [178,323]; 2017-2019: 207±237 95% CI [119,295]; P=0.319). When prescribed, doses of opioids provided at discharge were less in the more recent group (2012-2016: 84.4±78.9 95% CI [57.5, 111]; 2017-2019: 38.1±20.2 95% CI [33.7, 42.5]; P=0.004) CONCLUSION: Despite recognition of important drawbacks of opioid use for headache control, and efforts to reduce opioid use during hospitalization, we found that utilization during hospitalization for SAH did not decrease over time. Maximal headache scores remained similar in the studied time periods, indicative of insufficient pain relief. This points out a pressing need to further investigate alternative opioid and narcotic sparing strategies for patients with SAH.

Evaluating definitions for maternal fever as diagnostic criteria for intraamniotic infection in low-risk pregnancies

BACKGROUND

Conflicting statements by stakeholders in obstetric care have suggested different criteria for defining peripartum fever and suspected intraamniotic infection, which have not been evaluated.

METHODS

A case-control study of pregnancies between 35 and 41 weeks at a single tertiary care center between January 2016 and December 2017. Cases with pathology-confirmed chorioamnionitis were identified, and demographic data, risk factors, and neonatal outcomes were extracted from the medical record. The American College of Gynecology (ACOG) and National Institutes of Health (NIH) Workshop guidelines for identifying isolated maternal fever and suspected intraamniotic infection were applied, retrospectively. Odds ratios, sensitivity/specificity, and predictive value of each guideline for pathology-confirmed chorioamnionitis and for secondary outcomes of interest were determined.

RESULTS

943 mother-infant dyads were evaluated including 41 (4.3%) with pathology-confirmed chorioamnionitis. Among cases, 18 (43.9%) experienced any maternal temperature ≥38°C (100.4°F) with 12 (29.2%) and 8 (19.5%) cases meeting criteria for isolated maternal fever according to the ACOG and Workshop guidelines, respectively. Furthermore, the ACOG and Workshop guidelines correctly identified 6 (14.6%) and 3 (7.3%) of cases of pathology-confirmed chorioamnionitis with high agreement between definitions (κ = 0.63). Laboratory evaluation, antimicrobial exposure, and prolonged length of stay in offspring are substantially higher in cases as compared to controls.

CONCLUSIONS

Guidelines that rely on maternal fever definitions for the diagnosis of suspected intraamniotic infection exhibit high agreement with low sensitivity, but high specificity and negative predictive value for pathology-confirmed chorioamnionitis. Maternal temperature ≥38°C continues to drive clinical decision-making for both mother and offspring.

P–182 The mechanism of mouse embryo hatching and the impact of laser drilling the zona pellucida: an RNA sequencing study

Study question

What is the mechanism of embryo hatching? Will laser-assisted zona pellucida (ZP) drilling alter the embryonic transcriptome?

Summary answer

Hatching is an ATP-dependent process. Hatching is also associated with Rho-mediated signaling. Laser-assisted ZP drilling might cause alternation in embryo metabolism.

What is known already

Embryo hatching is a vital process for early embryo development and implantation. Animal data suggests that hatching is the result of multiple factors, such as mechanical pressure, protease activation, and the regulation of maternal secretions. However, little is known about the regulatory signaling mechanisms and the molecules involved. In addition, despite the extensive use of laser-assisted ZP drilling in the clinic, the safety profile of this technique at molecular level is very sparse. The impact of this technique on the embryonic transcriptome has not been studied systematically.

Study design, size, duration

Eighty mouse embryos were randomly divided into a laser ZP drilling group (n = 40) and an untreated group (n = 40). After treatment, embryos were cultured in vitro for two days. Then, hatching blastocyst (n = 8) and pre-hatching blastocyst (n = 8) from the untreated group, and the hatching blastocyst from the treatment group (n = 8) were processed for RNA sequencing (RNA-seq).

Participants/materials, setting, methods

Cryopreserved 8-cell stage mouse embryos (B6C3F1 × B6D2F1) were thawed, and a laser was used to drill the embryo ZP in the treatment group. Next, the treated and untreated embryos were individually cultured in vitro to the E4.5 blastocyst stage. The resulting blastocysts were lysed individually and used for subsequent cDNA library preparation and RNA-seq. Following data quality control and alignment, the RNA-seq data were processed for differentially expressed gene analysis and downstream functional analysis.

Main results and the role of chance

According to the RNA-seq data, 275 differentially expressed genes (DEGs) (230 up-regulated and 45 down-regulated, adjusted P &lt; 0.05) were identified when comparing hatching and pre-hatching blastocysts in the control groups. Analysis suggested that the trophectoderm is the primary cell type involved in hatching, and revealed the potential molecules causing increased blastocyst hydrostatic pressure (Aqp3 and Cldn4). Functional enrichment analysis suggested that ATP metabolism and protein synthesis were activated in hatching blastocysts. DEGs were found to be significantly enriched in several gene ontology terms, particularly in terms of the organization of the cytoskeleton and actin polymerisation (P &lt; 0.0001). Furthermore, according to QIAGEN ingenuity pathway analysis results, Rho signaling was implicated in blastocyst hatching (Actb, Arpc2, Cfl1, Myl6, Pfn1, Rnd3, Septin9, z-score=2.65, P &lt; 0.0001). Moreover, the potential role of hormones (estrogen (z-score=2.24) and prolactin (z-score=2.4)) and growth factors (AGT (z-score=2.41) and FGF2 (z-score=2.213)) were implicated in the hatching process as indicated by the upstream regulator analysis. By comparing the transcriptome between laser-treated and untreated hatching blastocysts, 47 DEGs were identified (adjusted P &lt; 0.05) following laser-assisted ZP drilling. These genes were enriched in metabolism-related pathways (P &lt; 0.05), including the lipid metabolism pathway (Mvd, Mvk, Aacs, Gsk3a, Pik3c2a, Aldh9a1) and the xenobiotic metabolism pathway (Aldh18a1, Aldh9a1, Keap1, and Pik3c2a).

Limitations, reasons for caution

Findings in mouse embryos may not be fully representative of human embryos. Furthermore, the mechanism of hatching revealed here might only reflect the hatching process of embryos in vitro. Further studies are now necessary to confirm these findings in different conditions and species to determine their clinical significance. Wider implications of the findings: Our study profiled the mouse embryo transcriptome during in vitro hatching, identified potential key genes and mechanisms for future study. In addition, for the first time, we revealed the impact of laser-assisted ZP drilling on the transcriptome, this may help us to assess and improve the existing technique.

Trial registration number

Not applicable

P-798 Fertility preservation in pre-pubertal boys with cancer: A three-dimensional prepubertal testicular organoid for in vitro spermatogonial stem cell propagation and spermatogenesis

Study question

Can a three-dimensional (3D) prepubertal testicular organoid be formed and provide an in vitro microenvironment for spermatogonial stem cells (SSCs) maintenance and future spermatogenesis?

Summary answer

Primary cells extracted from immature testicular tissue (ITT) or SSCs can be grown long-term as 3D organoids, providing the potential for in vitro study.

What is known already

Aggressive cancer treatments, such as chemo- or radiotherapy, can leave young prepubertal boys infertile. Such patients are recommended to undergo the cryopreservation of testicular material to protect future fertility. Within the testes, the specialized 3D structure and direct cell-to-cell interactions play a critical role in the proliferation and development of SSCs. Over recent decades, 3D culture systems and organoids have been used to culture cells in vitro, however, a system that allows investigations into testicular organogenesis in vitro, and its impact on the SSC niche, has yet to be developed.

Study design, size, duration

This study aims to develop a 3D organoid culture system to support the proliferation of SSCs and spermatogenesis. Primary bovine ITT cells and enriched SSCs were isolated and 3D organoids were generated by in vitro culture for up to 40 days. Organoid formation was observed after using different foundation cells seeded at different densities and cultured in medium containing gonadotropic supplements.

Participants/materials, setting, methods

Post-thaw bovine ITTs (2 weeks-of-age) were dissociated using two-step enzymatic digestion. Enriched SSCs were selected by Percoll gradients and differential plating. Viability and apoptosis were evaluated by trypan blue staining and TUNEL assays, respectively. SSCs were evaluated immunocytochemically for germ-cell markers (PGP-9.5, PLZF) and Sertoli cell markers (Vimentin, Sox9). Expression levels of SSCs and spermatogenesis-related genes (Plzf, Gfrα-1, Nanog, Oct4, Stra8, Thy1) were determined by real-time quantitative polymerase chain reaction (RT-qPCR).

Main results and the role of chance

The viability of digested cells from thawed ITTs was 78.667% ± 2.03. Total testicular cells (&lt;10% SSCs) and enriched SSCs(&gt;50% SSCs) were observed to self-assemble into structurally complex organoids recapitulating the cell type compartmentalization of the testis, in a 3D Matrigel-based culture system with 10% knockout serum replacement (KSR) culture medium, but not with 10% fetal bovine serum(FBS) medium. Testicular organoids were found to exhibit either a grape-like structure and a round-shape structure. Cytoplasmic extensions of spermatogonia/Sertoli cells were in contact with each other within a forming colony. Organoids were formed faster and larger when seeded at a final concentration of 1.5 × 106 cells/ml, compared to 5 × 105 cells/ml and 1.5 × 105 cells/ml. Organoids grew to a diameter of 400 μm within 10 - 15 days and were passaged by mechanical disruption at a ratio of 1:3 every 7 - 10 days. Immunocytochemistry results showed that clusters of PGP9.5 and PLZF-positive cells were present within the organoids. The expression of selected germ cell and spermatogenesis markers in the testicular organoids closely resembled that of primary testicular cells for up to 20 days of culture.

Limitations, reasons for caution

We used calves (2 weeks-of-age) as an animal model to study testicular organoids. This tissue may act differently than human tissues and may not fully represent prepuberty. Furthermore, we only evaluated gene expression levels for selected markers that may not represent the full functional capability of germ cells.

Wider implications of the findings

Testicular organoids, as an in vitro bioengineering testicular model, could potentially be used to study testicular tissue development, cellular interactions, endocrinology, and spermatogenesis, in the laboratory but may also be applied for clinical purposes in the future.

Trial registration number

University of Oxford

P–798 Fertility preservation in pre-pubertal boys with cancer: A three-dimensional prepubertal testicular organoid for in vitro spermatogonial stem cell propagation and spermatogenesis

Study question

Can a three-dimensional (3D) prepubertal testicular organoid be formed and provide an in vitro microenvironment for spermatogonial stem cells (SSCs) maintenance and future spermatogenesis?

Summary answer

Primary cells extracted from immature testicular tissue (ITT) or SSCs can be grown long-term as 3D organoids, providing the potential for in vitro study.

What is known already

Aggressive cancer treatments, such as chemo- or radiotherapy, can leave young prepubertal boys infertile. Such patients are recommended to undergo the cryopreservation of testicular material to protect future fertility. Within the testes, the specialized 3D structure and direct cell-to-cell interactions play a critical role in the proliferation and development of SSCs. Over recent decades, 3D culture systems and organoids have been used to culture cells in vitro, however, a system that allows investigations into testicular organogenesis in vitro, and its impact on the SSC niche, has yet to be developed.

Study design, size, duration

This study aims to develop a 3D organoid culture system to support the proliferation of SSCs and spermatogenesis. Primary bovine ITT cells and enriched SSCs were isolated and 3D organoids were generated by in vitro culture for up to 40 days. Organoid formation was observed after using different foundation cells seeded at different densities and cultured in medium containing gonadotropic supplements.

Participants/materials, setting, methods

Post-thaw bovine ITTs (2 weeks-of-age) were dissociated using two-step enzymatic digestion. Enriched SSCs were selected by Percoll gradients and differential plating. Viability and apoptosis were evaluated by trypan blue staining and TUNEL assays, respectively. SSCs were evaluated immunocytochemically for germ-cell markers (PGP–9.5, PLZF) and Sertoli cell markers (Vimentin, Sox9). Expression levels of SSCs and spermatogenesis-related genes (Plzf, Gfrα–1, Nanog, Oct4, Stra8, Thy1) were determined by real-time quantitative polymerase chain reaction (RT-qPCR).

Main results and the role of chance

The viability of digested cells from thawed ITTs was 78.667% ± 2.03. Total testicular cells (&lt;10% SSCs) and enriched SSCs(&gt;50% SSCs) were observed to self-assemble into structurally complex organoids recapitulating the cell type compartmentalization of the testis, in a 3D Matrigel-based culture system with 10% knockout serum replacement (KSR) culture medium, but not with 10% fetal bovine serum(FBS) medium. Testicular organoids were found to exhibit either a grape-like structure and a round-shape structure. Cytoplasmic extensions of spermatogonia/Sertoli cells were in contact with each other within a forming colony. Organoids were formed faster and larger when seeded at a final concentration of 1.5 × 106 cells/ml, compared to 5 × 105 cells/ml and 1.5 × 105 cells/ml. Organoids grew to a diameter of 400 μm within 10 - 15 days and were passaged by mechanical disruption at a ratio of 1:3 every 7 - 10 days. Immunocytochemistry results showed that clusters of PGP9.5 and PLZF-positive cells were present within the organoids. The expression of selected germ cell and spermatogenesis markers in the testicular organoids closely resembled that of primary testicular cells for up to 20 days of culture.

Limitations, reasons for caution

We used calves (2 weeks-of-age) as an animal model to study testicular organoids. This tissue may act differently than human tissues and may not fully represent prepuberty. Furthermore, we only evaluated gene expression levels for selected markers that may not represent the full functional capability of germ cells.

Wider implications of the findings: Testicular organoids, as an in vitro bioengineering testicular model, could potentially be used to study testicular tissue development, cellular interactions, endocrinology, and spermatogenesis, in the laboratory but may also be applied for clinical purposes in the future.

Trial registration number

University of Oxford