Biology subjects

Giovannini, A.

Publications and source records attributed to Giovannini, A..

7 recordsLinked to original sources

bioRxiv2024

Reproducible differentiation of pure ovarian support cells from clinical-grade hiPSCs as a novel infertility treatment

In vitro maturation (IVM) is an infertility treatment used during in vitro fertilization (IVF) procedures in which immature oocytes are matured outside the body, limiting the excessive hormone doses required for retrieval of ready-to-fertilize oocytes. To overcome the historically low embryo formation rate associated with IVM, we have recently demonstrated that co-culture of hiPSC-derived ovarian support cells (OSCs) yielded higher rates of oocyte maturation and euploid embryo formation, by mimicking the complex ovarian environment in vitro, offering a novel solution to overcome the IVM main limitation. To translate this process into clinics, we sourced and engineered a compliant female clinical-grade (CG) hiPSC line to derive OSCs with similar quality attributes and clinical outcomes to results previously demonstrated with a research hiPSC line. We further optimized our manufacturing protocols to enable increased scale and substituted reagents with appropriate higher-quality alternatives. This strategic approach to product development has successfully met scalable manufacturing needs and ultimately resulted in a product of improved reproducibility, purity, and efficacy. Our findings support the use of a similar strategy to fine-tune hiPSC-derived products facilitating translation to clinical applications.

bioengineering↗

bioRxiv2023

The optimization of Salmonella surveillance programmes for pullet and layer farms using between-farm distance as a risk factor

Human salmonellosis cases are often caused by Salmonella serovars Enteritidis and Typhimurium and a large percentage of Salmonella outbreaks is associated with the consumption of eggs and egg products. For this reason, many countries implemented general surveillance programmes for the detection and control of Salmonella on pullet and layer farms. The infection risk however varies between farms and the identification of risk factors for Salmonella infection may be used to improve the performance of these surveillance programmes. The aims of this study are therefore to determine 1) whether local farm density is a risk factor for the infection of pullet and layer farms by Salmonella Enteritidis and Typhimurium and 2) whether the sampling effort of surveillance programmes can be reduced by accounting for this risk factor, while still providing sufficient control of target serovars Enteritidis and Typhimurium. To assess the importance of local farm density as a risk factor, we fitted different transmission kernels to Israeli surveillance data during the period from June 2017 to April 2019. The analysis showed that the distance to infected farms significantly increases the infection risk by serovar Enteritidis within an approximately 4 km radius and by Typhimurium within an approximately 0.3 km radius. We subsequently used these kernels to derive a model for the between-farm R0 and used it to optimise a surveillance programme that subdivided layer farms into groups at low and at high risk of between-farm transmission based on the local farm density and allowed the sampling frequency to vary between these groups. In this design, the pullet farms were always sampled one week prior to pullet distribution. Our analysis showed that the risk-based surveillance programme was able to keep the between-farm R0 of serovars Enteritidis and Typhimurium below 1 for all pullet and layer farms, using a sampling effort that was reduced by 32% compared to the currently implemented surveillance programme in Israel. The results of our study therefore indicate that local farm density is an important risk factor for infection of pullet and layer farms by Salmonella Enteritridis and Typhimurium and can be used to improve the performance of surveillance programmes.

ecology↗

bioRxiv2023

Improved rescue of immature oocytes obtained from conventional gonadotropin stimulation cycles via human induced pluripotent stem cell-derived ovarian support cell co-culture

Structured AbstractO_ST_ABSPurposeC_ST_ABSTo determine if rescue in vitro maturation (IVM) of human oocytes can be improved by co-culture with ovarian support cells (OSCs) derived from human induced pluripotent stem cells (hiPSCs). MethodsFertility patients undergoing conventional ovarian stimulation for oocyte cryopreservation or IVF donated denuded immature germinal vesicle (GV) and metaphase I (MI) oocytes for research, which were allocated between either the control or intervention cultures. Fertility patients aged 25 to 45 years old donated immature oocytes under informed consent, with no additional inclusion criteria. The 24-28 hour OSC-IVM culture condition was composed of 100,000 OSCs in suspension culture with human chorionic gonadotropin (hCG), recombinant follicle stimulating hormone (rFSH), androstenedione and doxycycline supplementation. The Media-IVM control lacked OSCs and contained the same supplementation. Primary endpoints consisted of MII formation rate and morphological quality assessment. Additionally, metaphase spindle assembly location and oocyte transcriptomic profiles were assessed compared to in vivo matured MII oocyte controls. ResultsWe observed significant improvement in maturation outcome rates ([~]1.7X) for oocytes that underwent IVM with OSCs. Specifically, the OSC-IVM group yielded a maturation rate of 62% {+/-} 5.57% SEM versus 37% {+/-} 8.96% SEM in the Media-IVM (p=0.0138, unpaired t-test). Oocyte morphological quality between OSC-IVM and the Media-IVM control did not significantly differ. OSC-IVM resulted in MII oocytes with no instances of spindle absence and no significant difference in position compared to in vivo matured IVF-MII controls. OSC-IVM treated MII oocytes display a transcriptomic signature significantly more similar to IVF-MII controls than the Media-IVM control MII oocytes did. ConclusionThe novel OSC-IVM platform is an effective tool for rescue maturation of human oocytes obtained from conventional stimulation cycles, yielding oocytes with improved nuclear and cytoplasmic maturation. OSC-IVM shows broad utility for application in modern fertility treatment to improve the total number of available mature oocytes for fertility treatment.

developmental biology↗

bioRxiv2023

Human induced pluripotent stem cell-derived ovarian support cell co-culture improves oocyte maturation in vitro after abbreviated gonadotropin stimulation

Assisted reproductive technologies (ART) have significantly impacted fertility treatment worldwide through innovations such as in vitro fertilization (IVF) and in vitro maturation (IVM). IVM holds promise as a technology for fertility treatment in women who cannot or do not wish to undergo conventional controlled ovarian stimulation (COS). However, IVM has historically shown highly variable performance in maturing oocytes and generating oocytes with strong developmental capacity. Furthermore, recently reported novel IVM approaches are limited to use in cycles lacking human chorionic gonadotropin (hCG) triggers, which is not standard practice in fertility treatment. We recently reported the development of ovarian support cells (OSCs) generated from human induced pluripotent stem cells (hiPSCs) that recapitulate dynamic ovarian function in vitro. Here we investigate the potential of the se OSCs in an IVM co-culture system to improve the maturation of human cumulus-enclosed immature oocytes retrieved from abbreviated gonadotropin stimulated cycles. We reveal that OSC-IVM significantly improves maturation rates compared to existing IVM systems. Most importantly, we demonstrate that OSC-assisted IVM oocytes are capable of significantly improving euploid blastocyst formation and yielding blastocysts with normal global and germline differential methylation region methylation profiles, a key marker of their clinical utility. Together, these findings demonstrate a novel approach to IVM with broad applicability to modern ART practice. Structured AbstractO_ST_ABSObjectiveC_ST_ABSTo determine if in vitro maturation (IVM) of human oocytes can be improved by co-culture with ovarian support cells (OSCs) derived from human induced pluripotent stem cells (hiPSCs). DesignThree independent experiments were performed in which oocyte donors were recruited to undergo abbreviated gonadotropin stimulation and retrieved cumulus oocyte complexes (COCs) were randomly allocated between the OSC-IVM and control IVM conditions. SubjectsAcross the three experiments, a total of 67 oocyte donors aged 19 to 37 years were recruited for retrieval using informed consent. Anti-mullerian hormone (AMH) value, antral follicle count (AFC), age, BMI, and ovarian pathology were used for inclusion and exclusion criteria. Intervention and ControlThe OSC-IVM culture condition was composed of 100,000 OSCs in suspension culture supplemented with human chorionic gonadotropin (hCG), recombinant follicle stimulating hormone (rFSH), androstenedione and doxycycline. IVM controls comprised commercially-available IVM media without OSCs and contained either the same supplementation as above (media-matched control), or FSH and hCG only (IVM media control). In one experiment, an additional control using fetal ovarian somatic cells (FOSCs) was used with the same cell number and media conditions as in the OSC-IVM. Main Outcome MeasuresPrimary endpoints consisted of metaphase II (MII) formation rate and oocyte morphological quality assessment. A limited cohort of oocytes were utilized for secondary endpoints, consisting of fertilization and blastocyst formation rates with preimplantation genetic testing for aneuploidy (PGT-A) and embryo epigenetic analysis. ResultsOSC-IVM resulted in a statistically significant improvement in MII formation rate compared to the media-matched control, a commercially available IVM media control, and the FOSC-IVM control. Oocyte morphological quality between OSC-IVM and controls did not significantly differ. OSC-IVM displayed a trend towards improved fertilization, cleavage, and blastocyst formation. OSC-IVM showed statistically significant improvement in euploid day 5 or 6 blastocyst formation compared to the commercially available IVM media control. OSC-IVM embryos displayed similar epigenetic global and germline loci profiles compared to conventional stimulation and IVM embryos. ConclusionThe novel OSC-IVM platform is an effective tool for maturation of human oocytes obtained from abbreviated gonadotropin stimulation cycles, supporting/inducing robust euploid blastocyst formation. OSC-IVM shows broad utility with different stimulation regimens, including hCG triggered and untriggered oocyte retrieval cycles, making it a highly useful tool for modern fertility treatment.

developmental biology↗

bioRxiv2018

Disease persistence on temporal contact networks accounting for heterogeneous infectious periods

The infectious period of a transmissible disease is a key factor for disease spread and persistence. Epidemic models on networks typically assume an identical average infectious period for all individuals, thus allowing an analytical treatment. This simplifying assumption is however often unrealistic, as hosts may have different infectious periods, due, for instance, to individual host-pathogen interactions or inhomogeneous access to treatment. While previous work accounted for this heterogeneity in static networks, a full theoretical understanding of the interplay of varying infectious periods and time-evolving contacts is still missing. Here we consider an SIS epidemic on a temporal network with host-specific average infectious periods, and develop an analytical framework to estimate the epidemic threshold, i.e. the critical transmissibility for disease spread in the host population. Integrating contact data for transmission with outbreak data and epidemiological estimates, we apply our framework to three real-world case studies exploring different epidemic contexts - the persistence of bovine tuberculosis in southern Italy, the spread of nosocomial infections in a hospital, and the diffusion of pandemic influenza in a school. We find that the homogeneous parameterization may cause important biases in the assessment of the epidemic risk of the host population. Our approach is also able to identify groups of hosts mostly responsible for disease diffusion who may be targeted for prevention and control, aiding public health interventions.

epidemiology↗

bioRxiv2018

Network-based assessment of the vulnerability of Italian regions to bovine brucellosis

The endemic circulation of bovine brucellosis in cattle herds has a markedly negative impact on economy, due to decreased fertility, increased abortion rates, reduced milk and meat production. It also poses a direct threat to human health. In Italy, despite the long lasting efforts and the considerable economic investment, complete eradication of this disease still eludes the southern regions, as opposed to the northern regions that are disease-free. Here we introduced a novel quantitative network-based approach able to fully exploit the highly resolved databases of cattle trade movements and outbreak reports to yield estimates of the vulnerability of a cattle market to brucellosis. Tested on the affected regions, the introduced vulnerability indicator was shown to be accurate in predicting the number of bovine brucellosis outbreaks, thus confirming the suitability of our tool for epidemic risk assessment. We evaluated the dependence of regional vulnerability to brucellosis on a set of factors including premises spatial distribution, trading patterns, farming practices, herd market value, compliance to outbreak regulations, and exploring different epidemiological conditions. Animal trade movements were identified as a major route for brucellosis spread between farms, with an additional potential risk attributed to the use of shared pastures. By comparing the vulnerability of disease-free regions in the north to affected regions in the south, we found that more intense trade and higher market value of the cattle sector in the north, likely inducing more efficient biosafety measures, together with poor compliance to trade restrictions following outbreaks in the south were key factors explaining the diverse success in eradicating brucellosis. Our modeling scheme is both synthetic and effective in gauging regional vulnerability to brucellosis persistence. Its general formulation makes it adaptable to other diseases and host species, providing a useful tool for veterinary epidemiology and policy assessment.

epidemiology↗

bioRxiv2017

Farm productive realities and the dynamics of bovine viral diarrhea (BVD) transmission

Bovine Viral Diarrhea (BVD) is a viral disease that affects cattle and that is endemic to many European countries. It has a markedly negative impact on the economy, through reduced milk production, abortions, and a shorter lifespan of the infected animals. Cows becoming infected during gestation may give birth to Persistently Infected (PI) calves, which remain highly infective throughout their life, due to the lack of immune response to the virus. As a result, they are the key driver of the persistence of the disease both at herd scale, and at the national level. In the latter case, the trade-driven movements of PIs, or gestating cows carrying PIs, are responsible for the spatial dispersion of BVD. Past modeling approaches to BVD transmission have either focused on within-herd or between-herd transmission. A comprehensive portrayal, however, targeting both the generation of PIs within a herd, and their displacement throughout the Country due to trade transactions, is still missing. We overcome this by designing a multiscale metapopulation model of the spatial transmission of BVD, accounting for both within-herd infection dynamics, and its spatial dispersion. We focus on Italy, a country where BVD is endemic and seroprevalence is very high. By integrating simple within-herd dynamics of PI generation, and the highly-resolved cattle movement dataset available, our model requires minimal arbitrary assumptions on its parameterization. Notwithstanding, it accurately captures the dynamics of the BVD epidemic, as demonstrated by the comparison with available prevalence data. We use our model to study the role of the different productive realities of the Italian market, and test possible intervention strategies aimed at prevalence reduction. We find that dairy farms are the main drivers of BVD persistence in Italy, and any control strategy targeting these farms would lead to significantly higher prevalence reduction, with respect to targeting other production compartments. Our multiscale metapopulation model is a simple yet effective tool for studying BVD dispersion and persistence at country level, and is a good instrument for testing targeted strategies aimed at the containment or elimination of this disease. Furthermore, it can readily be applied to any national market for which cattle movement data is available.

epidemiology↗