De. Steen G, Demeestere I. P–434 Effect of let–7a mimic as a new pharmaco-protective agent against chemotherapy-induced ovarian damage on subsequent follicular development and oocyte quality using mouse ovarian transplantation model

Study question

What is the long-term impact of let–7a-mimic transfection on oocytes development in new-born mice ovaries exposed to chemotherapy in vitro following transplantation in the kidney?

Summary answer

The let–7a-mimic restoration protects against chemotherapy-induced ovarian apoptosis and preserves subsequent follicular developmental and acquisition of oocyte maturation competence in mouse.

What is known already

It is well known that cyclophosphamide and its active metabolites (4-hydroperoxycyclophosphamide, 4-HC) cause irreversible ovarian damage and impair future fertility of cancer survivors. Besides the available fertility preservation options, microRNAs/miRNAs appear to be very attractive and novel targets to prevent theses damage. We showed that miRNAs were dysregulated after exposure to 4-HC in postnatal-day–3 (PND3) ovaries, let–7a being the most downregulated among them. By replacing let–7a function, let–7a-mimic was able to protect mouse follicles against 4-HC in vitro. This previous study suggested that it could preserve the reproductive potential after treatment. However, the impact on subsequent oocytes development is unknown

Study design, size, duration

PND3 ovaries from C57blxCBAF1 hybrid mice were cultured under 3 conditions: control, chemotherapy for 24h (4-HC/20μΜ/24h), chemotherapy for 24h+let–7a-mimic (4-HC/20μΜ/24h+let–7a-mimic). Nine PND3 ovaries were cultured in the different conditions and then transplanted under the kidney’s capsule of C57blxCBAF1 hybrid adult mice for follicular growth/apoptosis evaluation. Then, 21 ovaries (≥7/condition) were used for oocyte maturation assessment after transplantation and ovarian stimulation. All transplanted mice were observed during 21 days before PND3 ovaries collection. Participants/materials, setting, methods: PND3 ovaries were cultured in vitro using inserts under different conditions. A liposome-based system was used to deliver let–7a-mimic into ovaries and QPCR-assays validated its expression levels after transfection. Apoptosis was evaluated by TUNEL Assay while haematoxylin/eosin staining was used for assessing the follicular morphology, stage and count. The oocyte maturation rate was evaluated at day 21 post-transplantation after gonadotropins injection, mechanical eggs collection and in vitro maturation for 24 hours.

Main results and the role of chance

The apoptosis assessment confirmed that let–7a-mimic transfection reduced the chemotherapy-induced damage in PND3 ovaries in vitro. The number of primordial follicles was significantly reduced (p < 0.05) compared to control after chemotherapy exposure. However, it was increased in chemo24h+let–7a-mimic compared to chemo24h alone while remaining lower than control (p > 0.05). Accordingly, the number of the transitory follicles reflecting follicular activation was significantly higher in chemo24h compared to control (p < 0.05) and chemo24h+let–7a-mimic but for the last one, the result was not significant. Consequently, chemotherapy induces follicle activation while let–7a restoration tends to slow down this effect. To evaluate the long-term effects of chemotherapy and let–7a-mimic transfection, in vitro exposed PND3 ovaries were transplanted under kidney’s capsule in female adult mice. After 21 days, the ovarian reserve was higher in control, but we observed a slight increase of follicular density in the chemo24+let–7a-mimic compared to chemo24h. Similarly, the percentage of damaged/apoptotic cells was higher in all chemotherapy exposed groups compared to control but the impact was lower after let–7a restoration (12,0% and 28,2% in chemo24+let–7a-mimic and chemo24h, respectively). Importantly, the oocyte maturation rate after transplantation was higher in chemo24h+let–7a-mimic compared to chemo24h (40% versus 18%, respectively), suggesting a preservation of oocytes maturation competence.

Limitations, reasons for caution

The multiple in vitro/in vivo steps may introduce study bias. Moreover, the oocyte competence and live offspring is currently evaluated. The blastocyst formation and embryo development from oocytes fertilized in vitro, are more relevant parameters for oocyte quality assessment. The birth of healthy animals will confirm let–7a-mimic-transfection safety.

Wider implications of the findings: Our previous study demonstrated the anti-apoptotic effect of let–7a restoration in mouse ovaries against chemotherapy. In the current study, we demonstrated a long-term beneficial effect of let–7a restoration strategy on follicular development and oocytes maturation capacity. The results open new perspectives in fertility preservation using pharmacological approach.

Trial registration number

Not applicable

Standardization in Quantitative Imaging: A Multicenter Comparison of Radiomic Features from Different Software Packages on Digital Reference Objects and Patient Data Sets

Radiomic features are being increasingly studied for clinical applications. We aimed to assess the agreement among radiomic features when computed by several groups by using different software packages under very tightly controlled conditions, which included standardized feature definitions and common image data sets. Ten sites (9 from the NCI's Quantitative Imaging Network] positron emission tomography–computed tomography working group plus one site from outside that group) participated in this project. Nine common quantitative imaging features were selected for comparison including features that describe morphology, intensity, shape, and texture. The common image data sets were: three 3D digital reference objects (DROs) and 10 patient image scans from the Lung Image Database Consortium data set using a specific lesion in each scan. Each object (DRO or lesion) was accompanied by an already-defined volume of interest, from which the features were calculated. Feature values for each object (DRO or lesion) were reported. The coefficient of variation (CV), expressed as a percentage, was calculated across software packages for each feature on each object. Thirteen sets of results were obtained for the DROs and patient data sets. Five of the 9 features showed excellent agreement with CV < 1%; 1 feature had moderate agreement (CV < 10%), and 3 features had larger variations (CV ≥ 10%) even after attempts at harmonization of feature calculations. This work highlights the value of feature definition standardization as well as the need to further clarify definitions for some features.

Data-driven beamforming technique to attenuate ballistocardiogram artefacts in electroencephalography-functional magnetic resonance imaging without detecting cardiac pulses in electrocardiography recordings

Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) is a very promising non‐invasive neuroimaging technique. However, EEG data obtained from the simultaneous EEG–fMRI are strongly influenced by MRI‐related artefacts, namely gradient artefacts (GA) and ballistocardiogram (BCG) artefacts. When compared to the GA correction, the BCG correction is more challenging to remove due to its inherent variabilities and dynamic changes over time. The standard BCG correction (i.e., average artefact subtraction [AAS]), require detecting cardiac pulses from simultaneous electrocardiography (ECG) recording. However, ECG signals are also distorted and will become problematic for detecting reliable cardiac peaks. In this study, we focused on a beamforming spatial filtering technique to attenuate all unwanted source activities outside of the brain. Specifically, we applied the beamforming technique to attenuate the BCG artefact in EEG–fMRI, and also to recover meaningful task‐based neural signals during an attentional network task (ANT) which required participants to identify visual cues and respond accurately. We analysed EEG–fMRI data in 20 healthy participants during the ANT, and compared four different BCG corrections (non‐BCG corrected, AAS BCG corrected, beamforming + AAS BCG corrected, beamforming BCG corrected). We demonstrated that the beamforming approach did not only significantly reduce the BCG artefacts, but also significantly recovered the expected task‐based brain activity when compared to the standard AAS correction. This data‐driven beamforming technique appears promising especially for longer data acquisition of sleep and resting EEG–fMRI. Our findings extend previous work regarding the recovery of meaningful EEG signals by an optimized suppression of MRI‐related artefacts.

Mask-Guided Convolutional Neural Network for Breast Tumor Prognostic Outcome Prediction on 3D DCE-MR Images

In this proof-of-concept work, we have developed a 3D-CNN architecture that is guided by the tumor mask for classifying several patient-outcomes in breast cancer from the respective 3D dynamic contrast-enhanced MRI (DCE-MRI) images. The tumor masks on DCE-MRI images were generated using pre- and post-contrast images and validated by experienced radiologists. We show that our proposed mask-guided classification has a higher accuracy than that from either the full image without tumor masks (including background) or the masked voxels only. We have used two patient outcomes for this study: (1) recurrence of cancer after 5 years of imaging and (2) HER2 status, for comparing accuracies of different models. By looking at the activation maps, we conclude that an image-based prediction model using 3D-CNN could be improved by even a conservatively generated mask, rather than overly trusting an unguided, blind 3D-CNN. A blind CNN may classify accurately enough, while its attention may really be focused on a remote region within 3D images. On the other hand, only using a conservatively segmented region may not be as good for classification as using full images but forcing the model's attention toward the known regions of interest.

AB0424 NUTRIENT DEFICIENCIES IN SYSTEMIC SCLEROSIS: A SYSTEMATIC REVIEW

Background:

Malnutrition is a critical concern in patients with systemic sclerosis (SSc).1,2 However, the extent and types of nutrient deficiencies in SSc remain unclear.

Objectives:

1) To identify the nutrient deficiencies commonly reported in SSc; 2) To evaluate associations between specific nutrient deficiencies and SSc subtype and clinical manifestations.

Methods:

We conducted a systematic review of all published reports on SSc and nutrition in PubMed from its inception to August 2020. Clinical trials, observational studies, and case series (with ≥20 cases) containing data on nutritional deficiency and SSc were included. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) for reporting our findings. Two reviewers (ADN and ERV) studied the titles and abstracts of all search results with pre-specified inclusion and exclusion criteria (Figure 1).

Results:

Among 790 retrieved publications, 35 full-length articles and 3 abstracts met the inclusion criteria. Included studies took place across multiple geographic locations and included patients with both diffuse and limited cutaneous SSc. Vitamin D deficiency was the most commonly reported deficiency described in SSc, followed by vitamin B12, folate, selenium, zinc, and iron (Table 1). In addition, some small studies found deficiencies in thiamine, pyridoxine, alpha-tocopherol, and carotene. Interstitial lung disease was associated with vitamin D deficiency and elevated homocysteine (Hcy), while pulmonary hypertension was associated with elevated Hcy. Vitamin D deficiency was also associated with increased modified Rodnan skin score (mRSS) and increased risk of SSc-related organ involvement.

Conclusion:

Nutrient deficiencies are common in SSc and are associated with specific SSc features. Routine screening for nutrient deficiencies may lead to early detection of malnutrition. Future studies are needed to understand how nutritional interventions affect patient outcomes in SSc.

References:

[1]Harrison E, Herrick AL, McLaughlin JT, Lal S. Malnutrition in systemic sclerosis. Rheumatology. 2012;51(10):1747-1756. doi:10.1093/rheumatology/kes160

[2]Baron M, Hudson M, Steele R, et al. Malnutrition is common in systemic sclerosis: Results from the Canadian Scleroderma Research Group database. J Rheumatol. 2009;36(12):2737-2743. doi:10.3899/jrheum.090694

Table 1.

Nutrient deficiencies and their clinical correlates in SSc.

Number of studies that found deficiencyaNumber of studies that did not find deficiencyClinical correlates of nutrient deficiencyVitamin D230 Increased risk of SSc-related organ involvement ILDc Higher mRSScHomocysteineb54 ILDc PHVitamin B1234 None identifiedFolate32 None identifiedVitamin C20 None identifiedSelenium50 Increased risk of SSc-related organ involvementZinc31 None identifiedIron11 None identifiedCopper02 None identifiedOther nutrients None identified for all nutrientsThiamine10Pyridoxine10Alpha-tocopherol10Carotene10

a Deficiency defined as below normal levels based on study reference ranges

b Studies looked for elevation versus no elevation of homocysteine in SSc

c Some studies found significant correlation while others did not

Acknowledgements:

I have no acknowledgements to declare.

Disclosure of Interests:

None declared

The association between social ties and depression among Asian and Pacific Islander undocumented young adults

BACKGROUND

The mental health of Asian and Pacific Islander (API) undocumented young adults has been understudied, despite an increasingly restrictive immigration climate that would ostensibly raise mental health risks. This study examined the role of social ties and depression among API undocumented young adults. We distinguished between two types of social ties, bonding and bridging, and additionally considered the absence of ties (e.g. isolation).

METHODS

We used primary data collected among 143 API undocumented young adults. We first identified correlates for each type of social tie and then examined the association for each measure with depression.

RESULTS

Higher levels of bonding and bridging ties were associated with lower odds of a positive depression screen. In contrast, isolation was associated with higher odds of a positive depression screen. There were no significant associations between total social ties and depression.

CONCLUSIONS

Our findings suggest that both bonding and bridging ties are important factors in the mental health of API undocumented young adults. Factors that facilitate these types of ties, such as DACA, can be effective interventions for improving mental health among this population.

Perceptions of Ontario chiropractors on business education in chiropractic schools

OBJECTIVE

Chiropractic, as a business in the health care system, has a component of entrepreneurship. Therefore, it is important to have business education in chiropractic schools. This study examines perceptions of business education in chiropractic schools as evaluated by Ontario, Canada, practicing chiropractors.

METHODS

We conducted a series of interviews with 16 chiropractors practicing in Ontario. Questions aimed at analyzing 2 levels of chiropractors' perceptions on the quality of business education they received. The questions were designed around 2 concepts: perceived level of business knowledge acquired and current level of knowledge for 6 business topics. The topics included accounting and finance, organizational behavior and human resources, legal and ethical issues, strategic management, managerial decision making, and operational management. Interview responses were analyzed by grouping significant statements into themes followed by descriptions of what and how the subjects experienced the phenomena.

RESULTS

The interviews revealed that Ontario practicing chiropractors' requirements for education in business skills are both broad and essential, embracing most if not all major business domains. Many participants indicated that the status of business education in chiropractic schools is minimally contributing to business skills following graduation.

CONCLUSION

Producing chiropractors with entrepreneurship skills requires enhanced business education in chiropractic schools. Perceptions of Ontario chiropractors reveal a gap between skill-oriented business training in chiropractic education and the skills needed to practice within the profession.