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Treatments for structural heart diseases (SHD) have been considerably evolved by the widespread of transcatheter approach in the last decades. The progression of transcatheter treatments for SHD was feasible due to the improvement of devices and the advances in imaging techniques. In this setting, the cardiovascular imaging is pivotal not only for the diagnosis but even for the treatment of SHD. With the aim of fulfilling these tasks, a multimodality imaging approach with new imaging tools for pre-procedural planning, intra-procedural guidance, and follow-up of SHD was developed. This review will describe the current state-of-the-art imaging techniques for the most common percutaneous interventions as well as the new imaging tools. The imaging approaches will be addressed describing the use in pre-procedural planning, intra-procedural guidance, and follow-up.

Heart failure with preserved ejection fraction (HFpEF) is a common clinical syndrome frequently seen in elderly patients, the incidence of which is steadily increasing due to an ageing population and the increasing incidence of diseases, such as diabetes, hypertension, obesity, chronic renal failure, and so on. It is a multifactorial disease with different phenotypic aspects that share left ventricular diastolic dysfunction, and is the cause of about 50% of hospitalizations for heart failure in the Western world. Due to the complexity of the disease, no specific therapies have been identified for a long time. Sodium-Glucose Co-Transporter 2 Inhibitors (SGLT2-Is) and Glucagon-Like Peptide Receptor Agonists (GLP-1 RAs) are antidiabetic drugs that have been shown to positively affect heart and kidney diseases. For SGLT2-Is, there are precise data on their potential benefits in heart failure with reduced ejection fraction (HFrEF) as well as in HFpEF; however, insufficient evidence is available for GLP-1 RAs. This review addresses the current knowledge on the cardiac effects and potential benefits of combined therapy with SGLT2-Is and GLP-1RAs in patients with HFpEF.

The mitochondrial encephalomyopathy, lactic acidosis, and stroke (MELAS) syndrome is a mitochondrial disorder, commonly caused by m.3243AG mutation in the MT-TL1 gene. It encodes for the mitochondrial leucine transfer RNA (tRNA Leu(UUR)), implicated in the translation of proteins involved in the assembly and function of mitochondrial complexes in the electron transport chain. The m.3243AG mutation determines complex I (CI) deficiency, ultimately leading to NADH accumulation, higher rates of glycolysis in order to compensate for the reduced ATP production and increase in lactates, the end-product of glycolysis. Disruption of the oxidative phosphorylation function with an inability to produce sufficient energy results in multi-organ dysfunction, with high energy demanding cells, such as myocytes and neurons, being the most affected ones. Therefore MELAS syndrome is characterized by a heterogeneous clinical spectrum. Here we report on a case of a 55-year-old man affected by MELA syndrome with no cardiovascular risk factors. He was admitted to our department because of a non ST-segment elevation myocardial infarction (NSTEMI). A coronary angioplasty of the posterior descending artery and of the left anterior descending artery was realized. Transthoracic echocardiography showed inferior and anterior left ventricular wall hypokinesis together with a moderate left ventricle hypertrophy.Cardiac involvement is reported in about a third of the patients and left ventricular hypertrophy (LVH) is the most common phenotype, with possible dilated cardiomyopathy in end-stage disease; brady- arrhythmias and tachy-arrhythmias are also frequently reported as well as Wolff- Parkinson-White (WPW) syndrome. Organ impairment and clinical manifestations depend on the heteroplasmy level of mutant DNA in cells that can differ among individuals, explaining why some patients present a more severe disease.A clear relationship between MELAS syndrome and atherosclerosis has never been established, however recently advocated. In vitro studies in MELAS patients have shown that higher mitochondrial ROS levels and increased expression of oxidative stress-related genes, as a consequence of complex I deficiency and disrupted electron transport, allow circulating LDL to be promptly oxidized into ox-LDL, contributing to endothelial dysfunction and atherosclerosis plaque formation.In light of the recent evidence suggesting a possible link between mitochondrial disorders and atherosclerosis, we speculate that MELAS syndrome may have played a role in the pathogenesis of coronary artery disease in our patient. Further investigations are needed to confirm a pathogenetic link.

Severe tricuspid valve (TV) regurgitation (TR) has been associated with adverse long-term outcomes in several natural history studies, but isolated TV surgery presents high mortality and morbidity rates. Transcatheter tricuspid valve interventions (TTVI) therefore represent a promising field and may currently be considered in patients with severe secondary TR that have a prohibitive surgical risk. Tricuspid transcatheter edge-to-edge repair (T-TEER) represents one of the most frequently used TTVI options. Accurate imaging of the tricuspid valve (TV) apparatus is crucial for T-TEER preprocedural planning, in order to select the right candidates, and is also fundamental for intraprocedural guidance and post-procedural follow-up. Although transesophageal echocardiography represents the main imaging modality, we describe the utility and additional value of other imaging modalities such as cardiac CT and MRI, intracardiac echocardiography, fluoroscopy, and fusion imaging to assist T-TEER. Developments in the field of 3D printing, computational models, and artificial intelligence hold great promise in improving the assessment and management of patients with valvular heart disease.

Mitral regurgitation (MR) is the second most frequent valve heart disease in Europe and its underlying mechanism primary-organic (due to disease of the mitral leaflets), or secondary-functional (where valve leaflets and chordae are structurally normal and MR results from alterations in left ventricle and left atrium geometry), determines the therapeutic approach. Transcatheter Edge-to-Edge Repair (TEER) with MitraClip implantation is a minimal-invasive treatment that according to 2021 ESC Guidelines should be considered (class indication IIa) in selected symptomatic patients with severe MR despite optimal medical therapy, not eligible for surgery and fulfilling COAPT trial inclusion criteria, suggesting an increased chance of responding to treatment. Optimal valve morphology features for TEER are central pathology (second scallop), no leaflet calcifications, mitral valve area >4 cm2, mobile length of posterior leaftel >10 mm, coaptation depth

Author(s): Belli, Martina; Secchi, Christian; Stupack, Dwayne; Shimasaki, Shunichi | Abstract: Adult granulosa cell tumor (aGCT) is a rare type of ovarian cancer characterized by estrogen excess. Interestingly, only the single somatic mutation FOXL2 C134W was found across virtually all aGCTs. We previously reported that FOXL2C134W stimulates CYP19 transcription synergistically with SMAD3, leading to elevated estradiol synthesis in a human granulosa cell line (HGrC1). This finding suggested a key role for FOXL2C134W in causing the typical estrogen overload in patients with aGCTs. We have now investigated the effect of FOXO1, a tumor suppressor, on CYP19 activation by FOXL2C134W in the presence of SMAD3. Intriguingly, FOXO1 antagonized the positive, synergistic effect of FOXL2C134W and SMAD3 on CYP19 transcription. Similar to FOXL2C134W, FOXO1 binds SMAD3 but not the proximal FOXL2C134W binding site (-199 bp) of the CYP19 promoter identified in our earlier studies. The results of a competitive binding assay suggested a possible underlying mechanism in which FOXO1 sequesters SMAD3 away from FOXL2C134W, thereby negating the cooperative action of FOXL2C134W and SMAD3 in inducing CYP19 expression. To our knowledge, this study is the first to demonstrate the ability of FOXO1 to restore an altered CYP19 expression by FOXL2C134W and SMAD3 and provides insight as to why FOXO1 deficiency promotes GCT development in mice.

Background In the ovarian follicle, the Theca Cells (TCs) have two main functions: preserving morphological integrity and, importantly, secreting steroid androgen hormones. TCs express the essential enzyme 17α-hydroxylase/17,20-desmolase (CYP17), which permits the conversion of pregnenolone and progesterone into androgens. Dysregulation of CYP17 enzyme activity due to an intrinsic ovarian defect is hypothesized to be a cause of hyperandrogenism in women. Androgen excess is observed in women with polycystic ovary syndrome (PCOS) resulting from excess endogenous androgen production, and in transgender males undergoing exogenous testosterone therapy after female sex assignment at birth. However, the molecular and morphological effects of Cyp17 overexpression and androgen excess on folliculogenesis is unknown. Methods In this work, seeking a comprehensive profiling of the local outcomes of the androgen excess in the ovary, we generated a transgenic mouse model (TC17) with doxycycline (Dox)-induced Cyp17 overexpression in a local and temporal manner. TC17 mice were obtained by a combination of the Tet-dependent expression system and the Cre/LoxP gene control system. Results Ovaries of Dox-treated TC17 mice overexpressed Cyp17 specifically in TCs, inducing high testosterone levels. Surprisingly, TC17 ovarian morphology resembled the human ovarian features of testosterone-treated transgender men (partially impaired folliculogenesis, hypertrophic or luteinized stromal cells, atretic follicles, and collapsed clusters). We additionally assessed TC17 fertility denoting a perturbation of the normal reproductive functions (e.g., low pregnancy rate and numbers of pups per litter). Finally, RNAseq analysis permitted us to identify dysregulated genes (Lhcgr, Fshr, Runx1) and pathways (Extra Cellular Matrix and Steroid Synthesis). Conclusions Our novel mouse model is a versatile tool to provide innovative insights into study the effects of Cyp17 overexpression and hyperandrogenism in the ovary.

Background: Myocardial injury (MI) can be detected during the acute phase of Coronavirus disease 19 (COVID-19) and is associated with a dismal prognosis. Recent imaging studies described the persistence of cardiac abnormalities after the recovery. The aim of the study was to investigate the spectrum of cardiac abnormalities at mid-term follow-up in patients recovered from COVID-19 using clinical assessment, laboratory tests, and imaging evaluation with comprehensive echocardiography. Methods: This is an observational, cross-sectional study assessing an unselected cohort of consecutive patients recovered from COVID-19. MI was defined by elevated plasma levels of high sensitive troponin T (hsTnT). At the follow-up, a complete examination including echocardiography was performed. Results: The 123 patients included were divided into two groups according to the presence of MI during hospitalization: group A (without MI) and group B (with MI). After a median of 85 days, group B patients were more frequently symptomatic for dyspnea and had significantly higher values of hsTnT and N-Terminal prohormone of Brain Natriuretic Peptide (NT-proBNP), compared to Group A. No differences between the two groups in left nor right ventricle dimension and ejection fraction were found. However, in group B a significant reduction of mean left ventricle global longitudinal strain was observed (-15.7±.7vs -18.1±.3 in group A, p&nbsp

Background Adult granulosa cell tumor (aGCT) is a rare type of stromal cell malignant cancer of the ovary characterized by elevated estrogen levels. aGCTs ubiquitously harbor a somatic mutation in FOXL2 gene, Cys134Trp (c.402C

BackgroundAdult granulosa cell tumor (aGCT) is a rare type of stromal cell malignant cancer of the ovary characterized by elevated estrogen levels. aGCTs ubiquitously harbor a somatic mutation in FOXL2 gene, Cys134Trp (c.402CC134W, its partner SMAD3 and its antagonist FOXO1 in cellular models of aGCT.MethodsIn this work, seeking more comprehensive profiling of FOXL2C134W transcriptomic effects, we performed an RNA-seq analysis comparing the effect of FOXL2WT/SMAD3 and FOXL2C143W/SMAD3 overexpression in an established human GC line (HGrC1), which is not luteinized, and bears normal alleles of FOXL2.ResultsOur data shows that FOXL2C143W/SMAD3 overexpression alters the expression of 717 genes. These genes include known and novel FOXL2 targets (TGFB2, SMARCA4, HSPG2, MKI67, NFKBIA) and are enriched for neoplastic pathways (Proteoglycans in Cancer, Chromatin remodeling, Apoptosis, Tissue Morphogenesis, Tyrosine Kinase Receptors). We additionally expressed the FOXL2 antagonistic Forkhead protein, FOXO1. Surprisingly, overexpression of FOXO1 mitigated 40% of the altered genome-wide effects specifically related to FOXL2C134W, suggesting it can be a new target for aGCT treatment.Conclusionsour transcriptomic data provide novel insights into potential genes (FOXO1 regulated) that could be used as biomarkers of efficacy in aGCT patients.

Background: Cyp17 plays a key role in theca cells (TCs) to produce androgens, which, in turn, are converted to estrogens in granulosa cells. Intrinsic alterations in ovarian steroidogenesis contribute to excessive ovarian androgen production that characterizes polycystic ovary disease (PCOS)1,2. Hyperandrogenism has been associated with higher levels of Cyp17 in TCs, and correlate with increased numbers of antral follicles3. While androgen excess is one of the hallmark features of PCOS, its putative role in the follicular development and function remains poorly known. Most efforts have used androgen administration or Cyp19 blockade approach to study how androgens prolong folliculogenesis4. Although some insights have been made, it is not clear if these models accurately address the cascade of effects that follow ovarian hyperandrogenism. Aim: Here, we aim to study the specific effects of hyperandrogenemia on ovarian morphology, follicle function and fertility with a new transgenic (TG) mouse model expressing elevated Cyp17 levels exclusively in TCs. Methods: We generated a breeding line of triple TG mice using a combination of the Tet-dependent expression system and the Cre/LoxP gene control system. Specifically, we used Cyp17 promoter-iCre mice crossed with trans-activator mice (R26-STOP-rtTA-IRES-EGFP transgene, Jackson Lab) and with a responder mouse carrying the TRE-Cyp17 transgene. Cyp17 promoter-iCre mice were used to ensure rtTA/EGFP is expressed specifically in TCs of secondary follicles. After the DNA segment between the two LoxP sites is excised by Cyp17iCre specifically in TCs, the R26-STOP-rtTA gene remains activated in all daughter TCs. Only upon treatment with Doxycycline (DOX) can suppression be relieved and active transcription of TRE-Cyp17 be induced in a dose-dependent manner. Results: Cyp17 mRNA expression levels in TCs of TG mice treated with 20, 100 or 200 mg/Kg DOX compared with corresponding untreated control mice showed a modulation in a dose-dependent manner (P=0.01 ANOVA). Confocal and RNAscope analysis validated (i) the effective combination of the Cyp17iCre/rtTA expression system visualizing the rtTA/EGFP specifically expressed in ovarian TCs and (ii) the DOX-induced increase of Cyp17 expression compared with the WT mice. DOX treated TG females were acyclic, being mostly arrested in diestrus. Analysis of estrous cycle stages revealed that treated TG females spent significantly more time in diestrus than control females (P=0.007, ANOVA). Conclusions: Our new in vivo model is the first that analyzes androgen impact independent of any extraovarian source of androgen, complementing current clinical efforts to study the occurrences of TCs elevated androgen levels in normal and PCOS women. 1 Rosenfield, R. L. et al. Endocr Rev (2016)2 Azziz, R. et al. Nat Rev Dis Primers (2016)3 Comim, F. V., et al. Hum Reprod (2013)4 Stener-Victorin, E. et al. Endocr Rev (2020)

Background: Adult granulosa cell tumor (aGCT) is a rare type of stromal cell malignant cancer of the ovary. Postmenopausal genital bleeding is the main aGCT clinical sign which is attributed to estrogen excess driven by CYP19 upregulation. Typically, aGCTs that are diagnosed at an initial stage can be treated with surgery. However, recurrences are mostly fatal1. Current studies are focused on finding new molecular markers and targets that aim to treat the aGCTs recurrence. Between 95-97% of aGCTs harbor a somatic mutation in the FOXL2 gene, Cys134Trp (c.402C

Adult granulosa cell tumor (aGCT) is a rare type of ovarian cancer characterized by estrogen excess. Interestingly, only the single somatic mutation FOXL2C134W was found across virtually all aGCTs. We previously reported that FOXL2C134W stimulates CYP19 transcription synergistically with SMAD3, leading to elevated estradiol synthesis in a human granulosa cell line (HGrC1). This finding suggested a key role for FOXL2C134W in causing the typical estrogen overload in patients with aGCTs. We have now investigated the effect of FOXO1, a tumor suppressor, on CYP19 activation by FOXL2C134W in the presence of SMAD3. Intriguingly, FOXO1 antagonized the positive, synergistic effect of FOXL2C134W and SMAD3 on CYP19 transcription. Similar to FOXL2C134W, FOXO1 binds SMAD3 but not the proximal FOXL2C134W binding site (−199 bp) of the CYP19 promoter identified in our earlier studies. The results of a competitive binding assay suggested a possible underlying mechanism in which FOXO1 sequesters SMAD3 away from FOXL2C134W, thereby negating the cooperative action of FOXL2C134W and SMAD3 in inducing CYP19 expression. To our knowledge, this study is the first to demonstrate the ability of FOXO1 to restore an altered CYP19 expression by FOXL2C134W and SMAD3 and provides insight as to why FOXO1 deficiency promotes GCT development in mice.

Infertility clinics would benefit from the ability to select developmentally competent vs. incompetent oocytes using non-invasive procedures, thus improving the overall pregnancy outcome. We recently developed a classification method based on microscopic live observations of mouse oocytes during their in vitro maturation from the germinal vesicle (GV) to the metaphase II stage, followed by the analysis of the cytoplasmic movements occurring during this time-lapse period. Here, we present detailed protocols of this procedure. Oocytes are isolated from fully-grown antral follicles and cultured for 15 h inside a microscope equipped for time-lapse analysis at 37 °C and 5% CO(2). Pictures are taken at 8 min intervals. The images are analyzed using the Particle Image Velocimetry (PIV) method that calculates, for each oocyte, the profile of Cytoplasmic Movement Velocities (CMVs) occurring throughout the culture period. Finally, the CMVs of each single oocyte are fed through a mathematical classification tool (Feed-forward Artificial Neural Network, FANN), which predicts the probability of a gamete to be developmentally competent or incompetent with an accuracy of 91.03%. This protocol, set up for the mouse, could now be tested on oocytes of other species, including humans.

Germline knockout studies in female mice demonstrated an essential role for forkhead box L2 (FOXL2) in early follicle development, whereas an inducible granulosa cell (GC)–specific deletion of Foxl2 in adults has shown ovary-to-testis somatic sex reprogramming. In women, over 120 different germline mutations in the FOXL2 gene have been shown to cause blepharophimosis/ptosis/epicantus inversus syndrome associated with or without primary ovarian insufficiency. By contrast, a single somatic mutation (FOXL2(C134W)) accounts for almost all adult-type GC tumors (aGCTs). To test the hypothesis that FOXL2(C134W) differentially regulates the expression of aGCT markers, we investigated the effect of FOXL2(C134W) on inhibin B and P450 aromatase expression using a recently established human GC line (HGrC1), which we now show to bear two normal alleles of FOXL2. Neither FOXL2(wt) nor FOXL2(C134W) regulate INHBB messenger RNA (mRNA) expression. However, FOXL2(C134W) selectively displays a 50-fold induction of CYP19 mRNA expression dependent upon activin A. Mechanistically, the CYP19 promoter is activated in a similar way by FOXL2(C134W) interaction with SMAD3, but not by FOXL2(wt). SMAD2 had no effect. Moreover, FOXL2(C134W) interactions with SMAD3 and with the FOX binding element located at –199 bp upstream of the ATG initiation codon of CYP19 are more sustainable than FOXL2(wt). Thus, FOXL2(C134W) potentiates CYP19 expression in HGrC1 cells via enhanced recruitment of SMAD3 to a proximal FOX binding element. These findings may explain the pathophysiology of estrogen excess in patients with aGCT.

Growth and differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are oocyte-secreted factors with a leading role in the control of ovarian function in female reproduction, modulating both the cell fate of the somatic granulosa cells and the quality and developmental competence of the egg. This short review aims to consolidate the molecular aspects of GDF9 and BMP15 and their integral actions in female fertility to understand particularly their effects on oocyte quality and fetal growth. The significant consequences of mutations in the GDF9 and BMP15 genes in women with dizygotic twins as well as the clinical relevance of these oocyte factors in the pathogenesis of primary ovarian insufficiency and polycystic ovary syndrome are also addressed.

Infertility in women is a health priority. Designing a robust culture protocol capable of attaining complete follicle growth is an exciting challenge, for its potential clinical applications, but also as a model to observe and closely study the sequence of molecular events that lie behind the intricate relationship existing between the oocyte and surrounding follicle cells. Here, we describe the procedures used to maintain the ovarian follicle 3D architecture employing a variety of in vitro systems and several types of matrices. Collagen and alginate are the matrices that led to better results, including proof-of-concept of full-term development. Pioneer in its kind, these studies underlie the drawbacks encountered and the need for a culture system that allows more quantitative analyses and predictions, projecting the culture of the ovarian follicle into the realm of tissue engineering.

Full-grown mouse antral oocytes are classified as surrounding nucleolus (SN) or not-surrounding nucleolus (NSN), depending on the respective presence or absence of a ring of Hoechst-positive chromatin surrounding the nucleolus. In culture, both types of oocytes resume meiosis and reach the metaphase II (MII) stage, but following insemination, NSN oocytes arrest at the two-cell stage whereas SN oocytes may develop to term. By coupling time-lapse bright-field microscopy with image analysis based on particle image velocimetry, we provide the first systematic measure of the changes to the cytoplasmic movement velocity (CMV) occurring during the germinal vesicle-to-MII (GV-to-MII) transition of these two types of oocytes. Compared to SN oocytes, NSN oocytes display a delayed GV-to-MII transition, which can be mostly explained by retarded germinal vesicle break down and first polar body extrusion. SN and NSN oocytes also exhibit significantly different CMV profiles at four main time-lapse intervals, although this difference was not predictive of SN or NSN oocyte origin because of the high variability in CMV. When CMV profile was analyzed through a trained artificial neural network, however, each single SN or NSN oocyte was blindly identified with a probability of 92.2% and 88.7%, respectively. Thus, the CMV profile recorded during meiotic resumption may be exploited as a cytological signature for the non-invasive assessment of the oocyte developmental potential, and could be informative for the analysis of the GV-to-MII transition of oocytes of other species.

The role that the transcription factor OCT4 plays during oocyte growth is yet unknown. In this review, we summarise the data on its potential role in the acquisition of oocyte developmental competence in the mouse. These studies describe the presence in MII oocytes and 2-cell embryos of an OCT4 transcriptional network that might be part of the molecular signature of maternal origin on which the inner cell mass and the embryonic stem cell-associated pluripotency is assembled and shaped. The Oct4-gene regulatory network thus provides a connection between eggs, early preimplantation embryos and embryonic stem cells.

In the mammalian oocyte, distinct patterns of centromeres and pericentromeric heterochromatin localisation correlate with the gamete’s developmental competence. Mouse antral oocytes display two main types of chromatin organisation: SN oocytes, with a ring of Hoechst-positive chromatin surrounding the nucleolus, and NSN oocytes lacking this ring. When matured to MII and fertilised, only SN oocytes develop beyond the 2-cell, and reach full term. To give detailed information on the dynamics of the SN or NSN chromatin during meiosis resumption, we performed a 9 hr time-lapse observation. The main significant differences recorded are: (1) reduction of the nuclear area only in SN oocytes; (2) ~17 min delay of GVBD in NSN oocytes; (3) chromatin condensation, after GVBD, in SN oocytes; (4) formation of 4-5 CHCs in SN oocytes; (5) increase of the perivitelline space, ~57 min later in NSN oocytes; (6) formation of a rosette-like disposition of CHCs, ~84 min later in SN oocytes; (7) appearance of the MI plate ~40 min later in NSN oocytes. Overall, we described a pathway of transition from the GV to the MII stage that is punctuated of discrete recordable events showing their specificity and occurring with different time kinetics in the two types of oocytes.

The oocyte-specific NOBOX protein is an important player during oocyte growth. Its absence in Nobox-/- mice arrests the transition from primordial to growing follicles and down-regulates the expression of a number of genes, including Oct4, a transcription factor crucial in the acquisition of oocyte developmental competence. Despite its role during folliculogenesis, a clear description of the expression of NOBOX throughout oocyte growth is lacking. Here, we have analysed the pattern of expression of both the Nobox gene (qRT-PCR) and its protein (immunofluorescence) during folliculogenesis, classifying the oocytes based on their size (six classes: 10-30, 31-40, 41-50, 51-60, 61-70, 71-80 microm) and chromatin organisation (NSN, Non Surrounded Nucleolus or SN, Surrounded Nucleolus). Significant differences were observed in Nobox transcription in the group of 41-50 microm (NSNSN), 71-80 microm (NSNSN) and in developmentally incompetent metaphase II-derived NSN (MII(NSN)) or competent metaphase II-derived SN (MII(SN)) oocytes (MII(NSN)MII(SN)). The NOBOX protein is expressed throughout oocyte growth in the nucleus of ovarian NSN and in MII(NSN) oocytes; in contrast, beginning with SN oocytes of 61-70 microm, it becomes almost undetectable. Our data, while being in line with the hypothesis of a regulative role of NOBOX on Oct4 gene expression at the primordial/primary stage, when both transcription factors are coincidentally expressed, also indicate that this role might not be maintained in the subsequent growing stages. Furthermore, the sharp difference of NOBOX expression in developmentally incompetent or competent oocytes makes this protein a putative marker of their quality.

The ovarian follicle has a three-dimensional (3D) structure in which the oocyte is surrounded by tightly connected follicle cells that mediate the action of external signals and nourish the gamete during its maturation. Thus, the maintenance of follicle organization during the whole growth process is crucial for the correct acquisition of developmental competence. In recent years, much attention has been given to in vitro culture systems capable of maintaining follicle architecture. With the aim of providing a quick reference guide, in this review we will summarize the techniques developed for the 3D culture of mouse follicles.