Pronuclear transfer rescues poor embryo development of in vitro-grown secondary mouse follicles

STUDY QUESTION

Is pronuclear transfer (PNT) capable of restoring embryo developmental arrest caused by cytoplasmic inferiority of in vitro-grown (IVG) mouse oocytes?

SUMMARY ANSWER

PNT to in vivo matured cytoplasm significantly improved embryo development of IVG mouse oocytes, leading to living, fertile offspring.

WHAT IS KNOWN ALREADY

In vitro follicle culture has been considered as a fertility preservation option for cancer patients. Studies describing the culture of human follicles remain scarce, owing to low availability of tissue. Mouse models have extensively been used to study and optimize follicle culture. Although important achievements have been accomplished, including the production of healthy offspring in mice, IVG oocytes are of inferior quality when compared to in vivo-grown oocytes, likely because of cytoplasmic incompetence.

STUDY DESIGN SIZE DURATION

The study was carried out from September 2020 to February 2022. In total, 120 15-day-old B6D2 mice were used to perform secondary follicle culture and assess the quality of IVG oocytes. In vivo-grown control oocytes were obtained from 85 8- to 12-week-old B6D2 mice, following ovarian stimulation. For sperm collection, four B6D2 males between 10 and 14 weeks old were used. For embryo transfer, 14 8- to 12-week-old CD1 females served as surrogate mothers and 10 CD1 vasectomized males 10-24 weeks old were used to generate pseudo-pregnant females. Finally, for mating, four B6D2 female mice aged 8-10 weeks and two B6D2 male mice aged 10 weeks old were used to confirm the fertility of nuclear transfer (NT)-derived pups.

PARTICIPANTS/MATERIALS SETTING METHODS

Secondary follicles from 15-day-old B6D2 mice were isolated from the ovaries and cultured for 9 days, before a maturation stimulus was given. Following 16-18 h of maturation, oocytes were collected and evaluated on maturation rate, oocyte diameter, activation rate, spindle morphology, calcium-releasing ability, and mitochondrial membrane potential. For every experiment, in vivo-grown oocytes were used as a control for comparison. When cytoplasmic immaturity and poor embryo development were confirmed in IVG oocytes, PNT was performed. For this, the pronuclei from IVG oocytes, created following parthenogenetic activation and IVF, were transferred to the cytoplasm of fertilized, in vivo-grown oocytes. Genetic analysis and embryo transfer of the generated embryos were implemented to confirm the safety of the technique.

MAIN RESULTS AND THE ROLE OF CHANCE

Following 9 days of follicle culture, 703 oocytes were collected, of which 76% showed maturation to the metaphase II stage. Oocyte diameters were significantly lower in IVG oocytes, measuring 67.4 μm versus 73.1 μm in controls (P < 0.001). Spindle morphology did not differ significantly between IVG and control oocytes, but calcium-releasing ability was compromised in the IVG group. An average calcium release of 1.62 arbitrary units was observed in IVG oocytes, significantly lower than 5.74 in control oocytes (P < 0.001). Finally, mitochondrial membrane potential was inferior in IVG compared to the control group, reaching an average value of 0.95 versus 2.27 (P < 0.001). Developmental potential of IVG oocytes was assessed following parthenogenetic activation with strontium chloride (SrCl2). Only 59.4% of IVG oocytes cleaved to two cells and 36.3% reached the blastocyst stage, significantly lower than 89.5% and 88.2% in control oocytes, respectively (P < 0.001 and 0.001). Both PNT and spindle transfer (ST) were explored in pilot experiments with parthenogenetically activated oocytes, as a means to overcome poor embryo development. After the added value of NT was confirmed, we continued with the generation of biparental embryos by PNT. For this purpose, IVG and control oocytes first underwent IVF. Only 15.5% of IVG oocytes were normally fertilized, in contrast to 45.5% in controls (P < 0.001), with resulting failure of blastocyst formation in the IVG group (0 versus 86.2%, P < 0.001). When the pronuclei of IVG zygotes were transferred to the cytoplasm of control zygotes, the blastocyst rate was restored to 86.9%, a similar level as the control. Genetic analysis of PNT embryos revealed a normal chromosomal profile, to a rate of 80%. Finally, the generation of living, fertile offspring from PNT was possible following embryo transfer to surrogate mothers.

LARGE-SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

Genetic profiles of analysed embryos from PNT originate from groups that are too small to draw concrete conclusions, whilst ST, which would be the preferred NT approach, could not be used for the generation of biparental embryos owing to technical limitations. Even though promising, the use of PNT should be considered as experimental. Furthermore, results were acquired in a mouse model, so validation of the technique in human IVG oocytes needs to be performed to evaluate the clinical relevance of the technology. The genetic profiles from IVG oocytes, which would be the ultimate characterization for chromosomal abnormalities, were not analysed owing to limitations in the reliable analysis of single cells.

WIDER IMPLICATIONS OF THE FINDINGS

PNT has the ability to overcome the poor cytoplasmic quality of IVG mouse oocytes. Considering the low maturation efficiency of human IVG oocytes and potential detrimental effects following long-term in vitro culture, NT could be applied to rescue embryo development and could lead to an increased availability of good quality embryos for transfer.

STUDY FUNDING/COMPETING INTERESTS

A.C. is a holder of FWO (Fonds voor Wetenschappelijk Onderzoek) grants (1S80220N and 1S80222N). B.H. and A.V.S. have been awarded with a special BOF (Bijzonder Onderzoeksfonds), GOA (Geconcerteerde onderzoeksacties) 2018000504 (GOA030-18 BOF) funding. B.H. has been receiving unrestricted educational funding from Ferring Pharmaceuticals (Aalst, Belgium). The authors declare that they have no conflict of interest.

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.

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

P-238 Treatment options to overcome impaired fertilization and embryonic development caused by an oocyte-related deficiency in the Patl2-/- mouse model

Study question

Can assisted oocyte activation (AOA) or spindle transfer (ST) overcome the lower fertilization and blastocyst rates observed in the Patl2-/- mouse model?

Summary answer

ST, but not AOA, has the potential to restore both normal fertilization and blastocyst rates in a mouse model with an oocyte-related deficiency.

What is known already

PATL2 is an RNA-transcriptional repressor involved in the regulation of maternal mRNAs during oocyte maturation. Mutations in PATL2 have been detected in patients with oocyte maturation arrest, reduced fertilization and embryo developmental arrest. Consequently, these patients are mostly referred to oocyte donation. Both AOA, inducing artificially calcium oscillations by calcium ionophores, and ST, replacing bad-quality oocyte cytoplasm with healthy cytoplasm, have been proposed to treat oocyte-related infertility. However, there is a lack of studies showing which oocyte-related infertility indications may benefit from which specific treatment. The Patl2-/- mouse model offers a unique opportunity to study the efficiency of these treatments.

Study design, size, duration

An experimental study using C57BL/6NTac-Patl2tm1a mice was conducted between April to December 2021. Breeding of heterozygous C57BL/6NTac-Patl2tm1a mice resulted in a total of 156 pups, from which 22 were homozygous C57BL/6NTac-Patl2tm1a ( Patl2-/-) females. Metaphase II (MII) oocytes were collected from Patl2-/- (test group) and Patl2+/+ (control group) females and used to evaluate different oocyte quality markers, as well as the efficiency of AOA and ST treatments to improve the oocyte-related subfertility observed in Patl2-/- mice.

Participants/materials, setting, methods

Four- to 12-week-old mice were subjected to ovarian hyperstimulation and oocyte collection, where oocyte maturation was assessed. Afterwards, MII oocytes were used to evaluate oocyte diameter, spindle abnormalities, activation rate (AR) and blastocyst rate (BR) after PIEZO-ICSI and calcium releasing capacity after SrCl2 exposure. Finally, Patl2-/- MII oocytes were treated with AOA, by direct exposure to SrCl2, or ST treatment, by transferring the Patl2-/- spindle to Patl2+/+ cytoplasm (previously enucleated) followed by SrCl2 exposure.

Main results and the role of chance

No difference in the number of cumulus-oocyte complexes (COCs) and mature MII oocytes was observed between 6 Patl2-/- mice (128 MII/159 COCs) and 5 Patl2+/+ mice (108 MII/132 COCs). However, Patl2-/- MII oocytes showed a significantly lower cytoplasm diameter (68,11 ± 2,25, n = 79) than Patl2+/+ oocytes (75,19 ± 2,09, n = 77, p-value&lt;0,001), suggesting that Patl2 affects oocyte growth but does not seem to affect oocyte maturation. Nuclear maturity was not compromised either, as a similar percentage of oocytes with normal spindle was observed in Patl2-/- (48,4%, 15/31) and Patl2+/+ MII oocytes (50%, 18/36). Activation and blastocyst rates after PIEZO-ICSI were lower in Patl2-/- (AR = 45,5%, 5/11 and BR = 20,0%, 1/5) than in Patl2+/+(AR = 75,0%, 21/28 and BR = 52,4%, 11/21).

In addition, total calcium released during oocyte activation after SrCl2 exposure was not different between Patl2-/- (AxF=6,88 AU, n = 30) and Patl2+/+ MII oocytes (AxF=5,04 AU, n = 28, p-value=0,087). In line with these results, AOA treatment did not improve activation and blastocyst rates in Patl2-/- oocytes (AR = 66,7%, 44/66 and BR = 45,5%, 20/44) compared to Patl2+/+ oocytes (AR = 96,5%, 110/114 and BR = 79,1%, 87/110, p-value&lt;0,001). Nonetheless, when performing ST using Patl2-/- as spindle donors and Patl2+/+ as cytoplasm recipients, activation (8/8, 100,0%) and blastocyst rate (6/8, 75,0%) were restored to normal values.

Limitations, reasons for caution

This study describes preliminary results and is limited by its small sample size. In addition, we did not identify an increased number of immature oocytes and spindle abnormalities in Patl2-/- female mice in contrast to previously published reports.

Wider implications of the findings

ST could be offered to treat PATL2- related female-infertility caused by a cytoplasmic deficiency, to increase both fertilization and blastocyst rates. AOA would not be beneficial for these patients as calcium releasing capacity of Patl2-/- oocytes does not seem to be affected, suggesting a deficiency independent from calcium releasing machinery.

Trial registration number

Not applicable

P–429 Calcium analysis and embryonic development of in vitro matured oocytes from transgender men

Study question

Can oocytes isolated from transgender men after oophorectomy support embryonic development?

Summary answer

Embryo developmental arrest at 4–8cell stage (day 3 embryos) indicates poor quality of in vitro matured oocytes from transgender men.

What is known already

Gender affirming surgery for transgender men leads to permanent infertility, as it involves bilateral oophorectomy. Current approaches for fertility preservation, such as oocyte freezing following ovarian hyperstimulation, may interfere with the wanted masculine characteristics and enhance gender dysphoria. In vitro matured oocytes (IVM) isolated following oophorectomy have been proposed as a source of potential gametes to ensure fertility preservation for transgender men with a child wish. From previous studies, it has been shown that these oocytes are able to undergo maturation and display normal spindles, but their competence to be fertilized and support embryonic development has not been addressed yet.

Study design, size, duration

We evaluated the quality of in vitro matured oocytes isolated from ovaries of transgender men by applying calcium imaging and monitoring fertilization and embryonic development following intracytoplasmic sperm injection (ICSI). Ovaries were collected in cold (4oC) or warm (37oC) medium, to investigate the best collection procedure. So far, results from four transgender men have been included. Participants/materials, setting, methods: Ovaries from four transgender men undergoing testosterone treatment were collected after oophorectomy in cold or warm medium. Cumulus oocyte complexes (COCs) were isolated and cultured in maturation medium for 48hrs. Mature oocytes were injected with donated sperm and assessed either by calcium imaging, measuring the total calcium release following injection, or following embryonic development. Donated in vitro matured oocytes, germinal vesicle(GV) or metaphase I(MI) origin, from other patients undergoing IVF treatment were used as controls.

Main results and the role of chance

In total, 179 COCs were collected from ovaries (n = 8) of four transgender men. From the COCs collected in warm medium, 73/105(69%) survived and 33/73(45%) reached metaphase II (MII). Of 21 MII injected with sperm, 13/21(62%) fertilized, 9/21(43%) formed 2 pronuclei (PN), 8/9(89%) reached the 2-cell stage, 3/9(33%) reached 4–8cell stage but arrested. From 74 COCs isolated in cold medium, 57/74(77%) survived and 28/57(49%) matured. Of the 11 MII injected with sperm, 7/11(64%) fertilized, 6/11(54%) formed 2PN, 6/6(100%) reached the 2-cell stage, 4/6(67%) reached 4–8cell but arrested. In the control group, 10/13 oocytes injected with the same sperm sample, were normally fertilized (77%), 8/10(80%) reached the 2-cell stage, 7/10(70%) reached the 4–8cell stage and 4/10(40%) became blastocysts. From the warm, cold and control conditions, respectively 12,14 and 17 MII oocytes were used for calcium imaging. The product of amplitude and frequency of calcium peaks, representing total calcium release, was calculated. Oocytes showed an average release of 0.66AU and 1.69AU for the warm and cold condition, respectively. The average value for control oocytes was 2.19AU.

Limitations, reasons for caution

One major limitation of our study is the lack of ovaries from cis women as control group. Our control oocytes originated from women undergoing IVF treatment and have undergone ovarian stimulation. Furthermore, the number of oocytes analysed and number of patients per group was limited and is being increased.

Wider implications of the findings: Our data indicate that in vitro matured oocytes from transgender men ovaries display poor quality, as demonstrated by the poor embryonic development. In the future, we will apply nuclear transfer technology as a mean to overcome embryonic developmental arrest in this group of oocytes.

Trial registration number

Not applicable

Expression of Retroelements in Mammalian Gametes and Embryos

Retroelements are genetic mobile elements, expressed during male and female gamete differentiation. Retrotransposons are normally regulated by the methylation machinery, chromatin modifications, non-coding RNAs, and transcription factors, while retrotransposition control is of vital importance in cellular proliferation and differentiation process. Retrotransposition requires a transcription step, by a cellular RNA polymerase, followed by reverse transcription of an RNA intermediate to cDNA and its integration into a new genomic locus. Long interspersed elements (LINEs), human endogenous retroviruses (HERVs), short interspersed elements (SINEs) and SINE-VNTR-Alu elements (SVAs) constitute about half of the human genome, play a crucial role in genome organization, structure and function and interfere with several biological procedures. In this mini review, we discuss recent data regarding retroelement expression (LINE-1, HERVK-10, SVA and VL30) and retrotransposition events in mammalian oocytes and spermatozoa, as well as the importance of their impact on human and mouse preimplantation embryo development.

Prospects of Germline Nuclear Transfer in Women With Diminished Ovarian Reserve

Diminished ovarian reserve (DOR) is associated with a reduced quantity and quality of the retrieved oocytes, usually leading to poor reproductive outcomes which remain a great challenge for assisted reproduction technology (ART). Women with DOR often have to seek for oocyte donation, precluding genetically related offspring. Germline nuclear transfer (NT) is a novel technology in ART that involves the transfer of the nuclear genome from an affected oocyte/zygote of the patient to the cytoplast of an enucleated donor oocyte/zygote. Therefore, it offers opportunities for the generation of genetically related embryos. Currently, although NT is clinically applied only in women with serious mitochondrial DNA disorders, this technology has also been proposed to overcome certain forms of female infertility, such as advanced maternal age and embryo developmental arrest. In this review, we are proposing the NT technology as a future treatment option for DOR patients. Strikingly, the application of different NT strategies will result in an increase of the total number of available reconstituted embryos for DOR patients.

Comorbidity of substance use and psychiatric disorders among inpatients of a General Hospital Psychiatric Unit

Introduction

In substance – related disorders comorbidity refers to any preexisting or following psychological or psychiatric condition that influence the course and prognosis of a patient.

Objectives

To determine the extent of comorbid substance use and psychiatric disorders among hospitalized in a General Hospital Psychiatric Unit patients and reveal the implications of treatment in such a unit.

Method

All patients hospitalized during a year, were included in the study. Demographics, final diagnosis, substance of use and means of admission (voluntary or involuntary) were recorded.

Results

7.4% of the total of 339 inpatients met the diagnostic criteria of comorbid substance use disorders. Eleven of them were diagnosed with alcohol use disorder comorbidity, 7 with illicit drug use comorbidity and 7 with both legal and illicit drug use comorbidity. Among inpatients with comorbid use disorders male patients had a significantly higher percentage versus females (x2 p < 0.05). Mean age of inpatients with comorbidity was significantly less than the mean age of the sample (t-test p < 0.05). Duration of hospitalization for inpatients with comorbidity was 15.16 ± 12.4 days versus 21.2 ± 18.4 days for the rest of patients (t-test p < 0.05). Concerning the way of admission, 72% of inpatients with comorbid use disorders were involuntary admitted (x2 p < 0.05).

Conclusion

Concerning age, sex and means of admission patients with a psychiatric disorder and substance use disorder comorbidity seem to vary from the rest of inpatients. These parameters are probably associated with serious difficulties in therapeutic compliance and with increased hazard.