Visualizing dynamic three-dimensional changes of human reticular dermal collagen under mechanical strain

In clinical practice, plastic surgeons are often faced with large skin defects that are difficult to close primarily. Management of large skin wounds e.g. burns or traumatic lacerations requires knowledge of skin biomechanic properties. Research into skin microstructural adaptation to mechanical deformation has only been performed using static regimes due to technical limitations. Here, we combine uniaxial stretch tests with fast second harmonic generation imaging and we apply this for the first time to investigate dynamic collagen rearrangement in reticular human dermis.Ex vivohuman skin from the abdomen and upper thigh was simultaneously uniaxially stretched while either periodically visualizing 3D reorganization, or visualizing 2D changes in real time. We determined collagen alignment via orientation indices and found pronounced variability across samples. Comparing mean orientation indices at the different stages of the stress strain curves (toe, heel, linear) showed a significant increase in collagen alignment during the linear part of the mechanical response. We conclude that fast SHG imaging during uni-axial extension is a promising research tool for future studies on skin biomechanic properties.

Characterization of ovarian tissue oocytes from transgender men reveals poor calcium release and embryo development, which might be overcome by spindle transfer

STUDY QUESTION

Can spindle transfer (ST) overcome inferior embryonic development of in vitro matured ovarian tissue oocytes (OTO-IVM) originating from testosterone-treated transgender men?

SUMMARY ANSWER

ST shows some potential to overcome the embryo developmental arrest observed in OTO-IVM oocytes from transgender men.

WHAT IS KNOWN ALREADY

OTO-IVM is being applied as a complementary approach to increase the number of oocytes/embryos available for fertility preservation during ovarian tissue cryopreservation in cancer patients. OTO-IVM has also been proposed for transgender men, although the potential of their oocytes remains poorly investigated. Currently, only one study has examined the ability of OTO-IVM oocytes originating from transgender men to support embryo development, and that study has shown that they exhibit poor potential.

STUDY DESIGN, SIZE, DURATION

Both ovaries from 18 transgender men undergoing oophorectomy were collected for the purposes of this study, from November 2020 to September 2022. The patients did not wish to cryopreserve their tissue for fertility preservation and donated their ovaries for research. All patients were having testosterone treatment at the time of oophorectomy and some of them were also having menses inhibition treatment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Sibling ovaries were collected in either cold or warm medium, to identify the most optimal collection temperature. Cumulus oocyte complexes (COCs) from each condition were isolated from the ovarian tissue and matured in vitro for 48 h. The quality of OTO-IVM oocytes was assessed by calcium pattern releasing ability, embryo developmental competence following ICSI, and staining for mitochondrial membrane potential. In vitro matured metaphase I (MI) oocytes, germinal vesicle (GV) oocytes, and in vivo matured oocytes with aggregates of smooth endoplasmic reticulum (SERa) were donated from ovarian stimulated women undergoing infertility treatment and these served as Control oocytes for the study groups. ST was applied to overcome poor oocyte quality. Specifically, enucleated mature Control oocytes served as cytoplasmic recipients of the OTO-IVM spindles from the transgender men. Embryos derived from the different groups were scored and analysed by shallow whole genome sequencing for copy number variations (CNVs).

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 331 COCs were collected in the cold condition (OTO-Cold) and 282 were collected in the warm condition (OTO-Warm) from transgender men. The maturation rate was close to 54% for OTO-Cold and 57% for OTO-Warm oocytes. Control oocytes showed a calcium releasing ability of 2.30 AU (n = 39), significantly higher than OTO-Cold (1.47 AU, P = 0.046) oocytes (n = 33) and OTO-Warm (1.03 AU, P = 0.036) oocytes (n = 31); both values of calcium release were similar between the two collection temperatures. Mitochondrial membrane potential did not reveal major differences between Control, OTO-Warm, and OTO-Cold oocytes (P = 0.417). Following ICSI, 59/70 (84.2%) of Control oocytes were fertilized, which was significantly higher compared to 19/47 (40.4%) of OTO-Cold (P < 0.01) and 24/48 (50%) of OTO-Warm oocytes (P < 0.01). In total, 15/59 (25.4%) blastocysts were formed on Day 5 in the Control group, significantly higher than 0/19 (0%) from the OTO-Cold (P = 0.014) and 1/24 (4.1%) in OTO-Warm oocytes (P = 0.026). Application of ST rescued the poor embryo development, by increasing the Day 5 blastocyst rate from 0% (0/19) to 20.6% (6/29) (P = 0.034), similar to that in the ICSI-Control group (25.4%, 15/59). A normal genetic profile was observed in 72.7% (8/11) of OTO-Cold, 72.7% (8/11) of OTO-Warm and 64.7% (11/17) of Control Day 3-Day 5 embryos. After ST was applied for OTO-IVM oocytes, 41.1% (7/17) of the embryos displayed normal genetic patterns, compared to 57.1% (4/7) among ST-Control Day 3-Day 5 embryos.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Due to the limited access to human oocytes and ovarian tissue, our results should be interpreted with some caution, as only a limited number of human oocytes and embryos could be investigated.

WIDER IMPLICATIONS OF THE FINDINGS

The results of this study, clearly indicate that OTO-IVM oocytes originating from transgender patients are of inferior quality, which questions their use for fertility preservation. The poor quality is likely to be related to cytoplasmic factors, supported by the increased blastocyst numbers following application of ST. Future research on OTO-IVM from transgender men should focus on the cytoplasmic content of oocytes or supplementation of media with factors that promote cytoplasmic maturation. A more detailed study on the effect of the length of testosterone treatment is also currently missing for more concrete guidelines and guidance on the fertility options of transgender men. Furthermore, our study suggests a potentially beneficial role of experimental ST in overcoming poor embryo development related to cytoplasmic quality.

STUDY FUNDING/COMPETING INTEREST(S)

A.C. is a holder of FWO grants (1S80220N and 1S80222N). A.B. is a holder of an FWO grant (1298722N). B.H. and A.V.S. have been awarded with a special BOF (Bijzonder Onderzoeksfonds), GOA (Geconcerteerde onderzoeksacties) and 2018000504 (GOA030-18 BOF) funding. B.H. has additional grants from FWO-Vlaanderen (Flemish Fund for Scientific Research, G051516N and G1507816N) and Ghent University Special Research Fund (Bijzonder Onderzoeksfonds, BOF funding (BOF/STA/202109/005)), and has been receiving unrestricted educational funding from Ferring Pharmaceuticals (Aalst, Belgium). The authors declare that they have no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Evaporative water loss from dairy cows in climate-controlled respiration chambers

The effects of ambient temperature (AT) on total evaporative water loss from dairy cows at different relative humidity (RH) and air velocity (AV) levels were studied. Twenty Holstein dairy cows with an average parity of 2.0 ± 0.7 and body weight of 687 ± 46 kg participated in the study. Two climate-controlled respiration chambers were used. The experimental indoor climate was programmed to follow a diurnal pattern with AT at night being 9°C lower than during the day. Night AT was gradually increased from 7 to 21°C and day AT was increased from 16°C to 30°C within an 8-d period, both with an incremental change of 2°C/d. The effect of 3 RH levels with a diurnal pattern were studied as well, with low values during the day and high values during the night: low (day, 30%; night, 50%), medium (day, 45%; night, 70%), and high (day, 60%; night, 90%). The effects of AV were studied during the daytime at 3 levels: no fan (0.1 m/s), fan at medium speed (1.0 m/s), and fan at high speed (1.5 m/s). The medium and high AV levels were only combined with medium RH. In total, there were 5 treatments with 4 replicates each. The animals had free access to feed and water. Based on the water balance principle inside the respiration chambers, the total evaporative water loss from dairy cows at a daily level was quantified by measuring the mass of water in the incoming and outgoing air, condensed water, added water from a humidifier, and evaporative water from a wet floor, drinking bowl, manure reservoir, and water bucket. Water evaporation from a sample skin area was measured with a ventilated skin box, and water evaporation, through respiration with a face mask. The results show that RH/AV levels had no significant effect on total evaporative water loss, whereas the interaction effect between RH/AV with AT was significant. Cows at a high RH had a tendency for a lower increasing rate of evaporative water loss compared with cows at a low RH (0.61 vs. 0.79 kg/d per 1°C increase of AT). Cows at medium and high AV levels had a greater increasing rate than cows at low AV (0.91 and 0.95 vs. 0.71 kg/d per 1°C increase of AT, respectively). The increase of evaporative heat loss from dairy cows was mainly a result of the increase in evaporation (of sweat) from the skin. The skin water evaporation determined with the water balance method (less evaporation from respiration) and the ventilated skin box method showed no significant difference. The implication of this study is that cows at a high AT depend mainly on evaporative cooling from the skin. The ventilated skin box method, measuring only a small part of the skin during a short period during the day, can be a convenient and accurate way to determine the total cutaneous evaporative water loss from cows.

Maternal rumen and milk microbiota shape the establishment of early-life rumen microbiota in grazing yak calves

Early-life gut microbial colonization and development exert a profound impact on the health and metabolism of the host throughout the life span. The transmission of microbes from the mother to the offspring affects the succession and establishment of the early-life rumen microbiome in newborns, but the contributions of different maternal sites to the rumen microbial establishment remain unclear. In the present study, samples from different dam sites (namely, oral, rumen fluid, milk, and teat skin) and rumen fluid of yak calves were collected at 6 time points between d 7 and 180 postpartum to determine the contributions of the different maternal sites to the establishment of the bacterial and archaeal communities in the rumen during early life. Our analysis demonstrated that the dam's microbial communities clustered according to the sites, and the calves' rumen microbiota resembled that of the dam consistently regardless of fluctuations at d 7 and 14. The dam's rumen microbiota was the major source of the calves' rumen bacteria (7.9%) and archaea (49.7%) compared with the other sites, whereas the potential sources of the calf rumen microbiota from other sites varied according to the age. The contribution of dam's rumen bacteria increased with age from 0.36% at d 7 to 14.8% at d 180, whereas the contribution of the milk microbiota showed the opposite trend, with its contribution reduced from 2.7% at d 7 to 0.2% at d 180. Maternal oral archaea were the main sources of the calves' rumen archaea at d 14 (50.4%), but maternal rumen archaea became the main source gradually and reached 66.2% at d 180. These findings demonstrated the potential microbial transfer from the dam to the offspring that could influence the rumen microbiota colonization and establishment in yak calves raised under grazing regimens, providing the basis for future microbiota manipulation strategies during their early life.

[Analysis of the effects of low/intermediate dose of coagulation factor Ⅷ on 30 adult patients with severe hemophilia A in a single center]

Objective: To evaluate the clinical effects of low- and intermediate-dose factor Ⅷ (F Ⅷ) prophylaxis in Chinese adult patients with severe hemophilia A. Methods: Thirty adult patients with severe hemophilia A who received low- (n=20) /intermediate-dose (n=10) F Ⅷ prophylaxis at Nanjing Drum Tower Hospital affiliated with Nanjing University Medical College were included in the study. The annual bleeding rate (ABR), annual joint bleeding rate (AJBR), number of target joints, functional independence score of hemophilia (FISH), quality of life score, and health status score (SF-36) before and after preventive treatment were retrospectively analyzed and compared. Results: The median follow-up was 48 months. Compared with on-demand treatment, low- and intermediate-dose prophylaxis significantly reduced ABR, AJBR, and the number of target joints (P<0.05) ; the improvement in the intermediate-dose prophylaxis group was better than that in the low-dose prophylaxis group (P<0.05). Compared with on-demand treatment, the FISH score, quality of life score, and SF-36 score significantly improved in both groups (P<0.05), but there was no significant difference between the two groups (P>0.05) . Conclusion: In Chinese adults with severe hemophilia A, low- and intermediate-dose prophylaxis can significantly reduce bleeding frequency, delay the progression of joint lesions, and improve the quality of life of patients as compared with on-demand treatment. The improvement in clinical bleeding was better with intermediate-dose prophylaxis than low-dose prophylaxis.

Does mental health mediate the effect of deviant peer affiliation on school adaptation in migrant children: evidence from a nationally representative survey in China

OBJECTIVES

This study aimed to examine the impact of deviant peer affiliation on migrant children's school adaptation in China and explore the mediating role of mental health in the relationship between deviant peer affiliation and school adaptation among migrant children.

STUDY DESIGN

This was a cross-sectional study based on secondary data.

METHODS

This study was based on the nationally representative China Education Panel Survey. Multiple linear regression models were used to quantify the relationship between deviant peer affiliation and school adaptation among 1,012 migrant children aged 12-17 years. Bootstrap test was used to evaluate the mediating effect of children's mental health.

RESULTS

Deviant peer affiliation showed a significant negative impact on the school adaptation of migrant children (β = -0.41, 95% confidence interval = -0.56 to -0.26). The relationship between deviant peer affiliation and school adaptation was partially mediated by children's mental health, resulting in an indirect effect of deviant peer affiliation on their school adaptation through their mental health (β = -0.05, 95% confidence interval = -0.09 to -0.03). The mediating role of mental health could explain 11.4% of the relationship between deviant peer affiliation and school adaptation.

CONCLUSIONS

Among migrant children, deviant peer affiliation showed unique effects on their school adaptation. Taking care of their mental health might help improve their school adaptation.

Circadian nuclear receptor Rev-erbalpha is expressed by platelets and potentiates platelet activation and thrombus formation

Background

Adverse cardiovascular events have day/night patterns with peaks in the morning, potentially related to endogenous circadian clock control of platelet activation. Circadian nuclear receptor Rev-erbα is an essential and negative component of the circadian clock.

Purpose

We aim to investigate the expression profile and biological function of Rev-erbα in platelets.

Methods and results

Here we report the presence and functions of circadian nuclear receptor Rev-erbα in human and mouse platelets. Both human and mouse platelet Rev-erbα showed a circadian rhythm that positively correlated with platelet aggregation. Global Rev-erbα knockout and platelet-specific Rev-erbα knockout mice exhibited defective in hemostasis as assessed by prolonged tail-bleeding times. Rev-erbα deletion also reduced ferric chloride-induced carotid arterial occlusive thrombosis, prevented collagen/epinephrine-induced pulmonary thromboembolism, and protected against microvascular microthrombi obstruction and infarct expansion in an acute myocardial infarction model. In vitro thrombus formation assessed by CD41-labeled platelet fluorescence intensity was significantly reduced in Rev-erbα knockout mouse blood. Platelets from Rev-erbα knockout mice exhibited impaired agonist-induced aggregation responses, integrin αIIbβ3 activation and α-granule release. Consistently, pharmacological inhibition of Rev-erbα by specific antagonists decreased platelet activation markers in both mouse and human platelets. Mechanistically, mass spectrometry and co-immunoprecipitation analyses revealed that Rev-erbα potentiated platelet activation via oligophrenin-1-mediated RhoA/ERM (ezrin/radixin/moesin) pathway.

Conclusion

We provide the first evidence that circadian protein Rev-erbα is functionally expressed in platelets and potentiates platelet activation and thrombus formation. Rev-erbα may serve as a novel therapeutic target for managing thrombosis-based cardiovascular disease.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): This work was supported by grants from the National Science Fund for Distinguished Young Scholars (81625002), the National Natural Science Foundation of China (81930007).

Risk stratification for systemic lupus erythematosus associated pulmonary hypertension by simplified ESC/ERS guidelines: data from SOPHIE registry

Background

The ESC/ERS guideline has established a diagnostic algorithm for pulmonary hypertension (PH) based on the peak velocity of tricuspid regurgitation, clinical history of left heart disease, chest radiography, and other chest radiological techniques. Unfortunately, due to the medical resource limitations, not all patients can receive the comprehensive inspections listed above.

Purpose

The purpose of the study was to sort out the practical predicting factors and evaluate the efficacy of the simplified diagnostic algorithm derived from the 2015 ESC/ERS clinical guidelines.

Methods

According to the ESC/ERS guideline, patients in the intermediate or high echocardiographic probability of PH group and further satisfied the following risk stratification criteria (anti-RNP (+), Raynaud phenomenon (+), 6MWD &lt;440 meters, and SVR &gt;1500 wood) were considered to have the intermediate (IR), and high risk (HR) of PH. Patients with a low echocardiographic probability of PH and those with intermediate or high probability of PH without satisfied the risk stratification algorithm were categorized into the low risk (LR) of the PH group.

Results

1005 patients were categorized into the LR group, 30 patients in the IR group, and 19 in the HR group. Precisely, patients in the LR group were relatively younger (49.9±0.4) than that of the IR group (57.8±2.3, p=0.001) and the HR group (56.0±3.0, p=0.035). Raynaud phenomenon was occurred more frequently in the IR group (50.0%) or HR group (47.4%) compared to that of the LR group (24.1%). The occurrence of anti-RNP positive was higher in the HR group, taken up for 57.9% compared to 31.5% in the LR group (p=0.013). The incidence of right axis deviation (RAD) was increasing in the IR group (17.2%) and HR group (16.7%) compared to the LR group (3.6%). In addition, patients in IR and HR group have reduced lung volume parameters, including forced vital capacity (FVC%), forced expiratory volume at the first second (FEV1%), FEV1/FVC ratio, and forced expiratory flow at 50% of forced vital capacity (FEF50%) when compared to the LR group. Multivariate analysis was performed in four different modes to sort out the independent predictors of PH. Anti-RNP (OR=10.5, CI: 1.9, 56.5) and RAD (OR=21.9, CI: 5.2, 92.2) in mode 1, RVH (OR=10.4, CI: 1.9, 56.3) in mode 2, RAD (OR=10.3, CI: 2.0, 50.7) and FEF50% (OR=1.0, CI: 0.90, 0.97) in mode 3, and RVH (OR=56.8, CI: 6.9, 467.5) and FEF50% (OR=1.0, CI: 0.90, 0.97) in mode 4 were identified as the independent predictors of PH for SLE patients.

Conclusions

This registry has provided main clinical characteristics and phenotypes of Hong Kong Chinese patients with SLE and has demonstrated that Anti-RNP, RAD, RVH, or FEF50% was independent predictors of pulmonary hypertension in patients with SLE.

Funding Acknowledgement

Type of funding sources: None.

[Diethylhexyl phthalate induces anxiety-like behavior and learning and memory impairment in mice probably by damaging blood-brain barrier]

OBJECTIVE

To investigate the effects of diethylhexyl phthalate (DEHP) exposure on anxiety-like behaviors and learning and memory ability in mice and explore the underlying mechanism.

METHODS

Forty male ICR mice were randomized equally into control group (0 mg/kg) and 10, 50 and 100 mg/kg DEHP exposure groups, in which the mice were exposed to DEHP at the indicated doses by gavage for 4 weeks. After the treatments, the mice were assessed for behavioral changes using open filed test, elevated plus-maze and Morris water maze test. Brain tissues were collected from the mice for determination of malondialdehyde (MDA) content, pathologies and expressions of ZO-1 and occludin in the hippocampus.

RESULTS

Compared with the control group, the mice with DEHP exposure for 4 weeks exhibited no significant body weight change (P>0.05) but presented with obvious behavioral changes, manifested by reduced movement distance (P < 0.05) and time spent in the center of the open field (P < 0.05), reduced movement distance (P < 0.05) and time spent in the open arm of the elevated maze (P < 0.05), significantly increased latency of searching for the platform (P < 0.05), and decreased frequency of crossing the platform (P < 0.05). HE staining showed obvious vertebral cell death in the hippocampal CA1 to CA3 regions of the mice with DEHP exposure. The exposed mice showed significantly increased MDA content and decreased expressions of ZO-1 and occludin at both the mRNA and protein levels in the hippocampus (P < 0.05 or 0.01). Multivariate linear regression analysis suggested a close correlation between anxiety-like behaviors and learning and memory abilities in DEHP-exposed mice.

CONCLUSION

DEHP exposure may cause damages of the blood-brain barrier and the pyramidal cells in the hippocampus of mice, thereby inducing anxiety-like behaviors and learning and memory impairment.

Identifying important ecosystem service areas based on distributions of ecosystem services in the Beijing-Tianjin-Hebei region, China

Water conservation, soil conservation, biodiversity importance, and sandstorm prevention are important ecosystem services (ES) and the core challenges to sustainable economic and societal development in the Beijing-Tianjin-Hebei (BTH) region. Using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model and observation data, we identified high-value ES areas in the BTH region. The high-value ES areas were mainly found in the northern and southwestern parts of the region, like the Yanshan Mountain Range and the Taihang Mountain Range. The ecosystem in the northern mountains is dominated by forest and grassland, and generally provides more valuable ES than does the eastern agricultural plain. Greater species richness was mainly found in the northern mountains with low human activity intensity. Due to its proximity, the Yanshan Mountain Range is critical to the health of the local ecosystem of Beijing. High biodiversity was present in the vicinity of the national nature reserves. Compared with other regions of China, changes in the BTH region are highly intense. Reinforcement of biodiversity conservation and ecosystem restoration in areas with a high degree of ES in the BTH region are capable of effectively improving habitat quality and regional ES.

Efficacy and safety of outpatient parenteral antibiotic therapy in patients with infective endocarditis: a meta-analysis

OBJECTIVE

To investigate the clinical outcome of patients with infective endocarditis (IE) during and after outpatient parenteral antimicrobial treatment (OPAT), and to further clarify the safety and efficacy of OPAT for IE patients.

METHODS

Through December 20, 2021, a total of 331 articles were preliminarily searched in Pubmed, Web of Science, Cochrane Library and Embase, and 9 articles were eventually included in this study.

RESULTS

A total of 9 articles comprising 1,116 patients were included in this study. The overall mortality rate of patients treated with OPAT was 0.04 (95% CI, 0.02-0.07), that means 4 deaths per 100 patients treated with OPAT. Separately, mortality was low during the follow-up period after OPAT treatment, with an effect size (ES) of 0.03 (95%CI, 0.02-0.07) and the mortality of patients during OPAT treatment was 0.04 (95% CI, 0.01-0.12). In addition, the readmission rate was found to be 0.14 (95% CI, 0.09-0.22) during the follow-up and 0.18 (95% CI, 0.08-0.39) during treatment, and 0.16 (95% CI, 0.10-0.24) for patients treated with OPAT in general. Regarding the relapse of IE in patients, our results showed a low overall relapse rate, with an ES of 0.03 (95% CI, 0.01-0.05). In addition, we found that the incidence of adverse events was low, with an ES of 0.26 (95% CI, 0.19-0.33).

CONCLUSIONS

In general, the incidence of adverse events and mortality, readmission, and relapse rates in IE patients treated with OPAT are low both during treatment and follow-up period after discharge, indicating that OPAT is safe and effective for IE patients. However, our study did not compare routine hospitalization as a control group, so conclusions should be drawn with caution. In order to obtain more scientific and rigorous conclusions and reduce clinical risks, it is still necessary to conduct more research in this field and improve the patient selection criteria for OPAT treatment, especially for IE patients. Finally, clinical monitoring and follow-up of OPAT-treated patients should be strengthened.

P-457 Spindle transfer rescues poor embryo development of in vitro matured ovarian tissue oocytes from transgender men

Study question

Could collection temperature and spindle transfer (ST) potentially improve development of embryos derived from in vitro matured (IVM) ovarian tissue oocytes (OTO) of transgender men?

Summary answer

Spindle transfer, but not collection temperature, significantly improved embryo development of OTO-IVM oocytes from transgender men.

What is known already

For transgender men, the fertility preservation strategy of ovarian stimulation may interfere with the desired masculine characteristics and enhance gender dysphoria. Alternatively, ovarian tissue oocytes collected ex vivo could serve as potential gametes, not requiring ovarian stimulation. Oocytes can be collected during gender affirming surgery, matured, and vitrified. Ovarian tissue oocyte in vitro maturation (OTO-IVM) has successfully been used for cancer patients, as live births have been reported. OTO-IVM in transgender men demonstrated sufficient maturation rates and survival following vitrification. Nevertheless, a decreased fertilization potential of these oocytes and severely compromised embryonic development have been observed.

Study design, size, duration

Patients between 18-24 years were recruited for this study from November 2020 to September 2021. Ovaries from 14 transgender men were collected in either cold (4oC, OTO-Cold) or warm (37oC, OTO-Warm) collection medium, to verify the best collection method. Following ovarian manipulation, cumulus oocyte complexes (COCs) were harvested from spent medium and underwent maturation for 48hrs. ST was performed to overcome inferior fertilization and embryonic development.

Participants/materials, setting, methods

Injected IVM oocytes underwent calcium imaging or were monitored for embryonic developmental potential. In vitro matured GV (germinal vesicle), MI (metaphase I) and in vivo matured oocytes with clusters of smooth endoplasmic reticulum (SERa) served as controls and cytoplasmic recipients for ST. OTO-IVM or control oocytes were used as spindle donors (ST-OTO or Control-ST respectively). Genetic analysis was performed to detect chromosomal abnormalities in embryos from all groups.

Main results and the role of chance

In total, we collected 252 OTO-Cold and 230 OTO-Warm oocytes, showing similar maturation rates (53%). For calcium imaging, 39 control, 33 OTO-cold and 31 OTO-warm oocytes were analysed, determining the product of amplitude per frequency, in arbitrary units (AU). The average value for control oocytes was 2.30AU, significantly higher than OTO-Cold (1.47AU, p=0.046) and OTO-Warm oocytes (1.03AU, p=0.036). Calcium release was similar between OTO-Cold and OTO-Warm oocytes. Following ICSI, 19/47 OTO-Cold and 24/48 OTO-Warm oocytes normally fertilized, significantly lower than the control group (42/52) (p &lt; 0.001 and p = 0.001 respectively). Blastocyst formation was significantly higher in control oocytes (13/42,31%) when compared to OTO-Cold (1/19, p=0.027) and OTO-Warm (2/24, p=0.035). No statistically significant difference in fertilization rate and embryo development was detected between OTO-Cold and OTO-Warm oocytes. ST was performed to overcome poor embryo development in the OTO-Cold group. Following ST, 12/19 ST-OTO-Cold and 24/38 Control-ST oocytes were normally fertilized. Blastocyst development was similar between the two groups (4/12 and 7/24 respectively), but significantly higher than blastocyst development in OTO-Cold ICSI oocytes (p = 0.038 and p = 0.045). Genetic analysis revealed that 4/10 OTO-Cold, 4/11 OTO-Warm, 4/11 ICSI control, and 4/7 Control-ST embryos were chromosomally abnormal while 6/8 OTO-ST were abnormal, and 2/8 showed a suggestive low-grade mosaicism.

Limitations, reasons for caution

A major limitation of our study is the lack of ovaries from cis women. Control oocytes used in this study originate from infertility patients that underwent ovarian stimulation. High abnormality rate in ST-OTO embryos might be concerning for the safety of ST, but the number of embryos analysed is limited.

Wider implications of the findings

Our data indicate that OTO-IVM oocytes from transgender men display poor cytoplasmic quality, demonstrated by embryonic arrest and calcium imaging. ST was able to overcome poor embryo development, and it could be of interest to use freshly donated oocytes as cytoplasmic recipients for this.

Trial registration number

Not applicable