Extracellular vesicles in nanomedicine and regenerative medicine: A review over the last decade.

Small extracellular vesicles (sEVs) are known to be secreted by a vast majority of cells. These sEVs, specifically exosomes, induce specific cell-to-cell interactions and can activate signaling pathways in recipient cells through fusion or interaction. These nanovesicles possess several desirable properties, making them ideal for regenerative medicine and nanomedicine applications. These properties include exceptional stability, biocompatibility, wide biodistribution, and minimal immunogenicity. However, the practical utilization of sEVs, particularly in clinical settings and at a large scale, is hindered by the expensive procedures required for their isolation, limited circulation lifetime, and suboptimal targeting capacity. Despite these challenges, sEVs have demonstrated a remarkable ability to accommodate various cargoes and have found extensive applications in the biomedical sciences. To overcome the limitations of sEVs and broaden their potential applications, researchers should strive to deepen their understanding of current isolation, loading, and characterization techniques. Additionally, acquiring fundamental knowledge about sEVs origins and employing state-of-the-art methodologies in nanomedicine and regenerative medicine can expand the sEVs research scope. This review provides a comprehensive overview of state-of-the-art exosome-based strategies in diverse nanomedicine domains, encompassing cancer therapy, immunotherapy, and biomarker applications. Furthermore, we emphasize the immense potential of exosomes in regenerative medicine.

Bioprinting of a Liposomal Oxygen-Releasing Scaffold for Ovary Tissue Engineering.

This study addresses a critical challenge in bioprinting for regenerative medicine, specifically the issue of hypoxia compromising cell viability in engineered tissues. To overcome this hurdle, a novel approach using a microfluidic bioprinter is used to create a two-layer structure resembling the human ovary. This structure incorporates a liposomal oxygen-releasing system to enhance cell viability. The bioprinting technique enables the simultaneous extrusion of two distinct bioinks, namely, bioink A (comprising alginate 1% and 5 mg/mL PEGylated fibrinogen in a 20:1 molar ratio) and bioink B (containing alginate 0.5%). In addition, liposomal catalase and hydrogen peroxide (H2O2) are synthesized and incorporated into bioinks A and B, respectively. The liposomes are prepared using thin film hydration with a monodisperse size (140-160 nm) and high encapsulation efficiency. To assess construct functionality, isolated human ovarian cells are added to bioink A. The bioprinted constructs, with or without liposomal oxygen-releasing systems, are cultured under hypoxic and normoxic conditions for 3 days. Live/Dead assay results demonstrate that liposomal oxygen-releasing systems effectively preserve cell viability in hypoxic conditions, resembling viability under normoxic conditions without liposomes. PrestoBlue assay reveals significantly higher mitochondrial activity in constructs with liposomal oxygen delivery systems under both hypoxic and normoxic conditions. The evaluation of apoptosis status through annexin V immunostaining shows that liposomal oxygen-releasing scaffolds successfully protect cells from hypoxic stress, exhibiting a proportion of apoptotic cells similar to normoxic conditions. In contrast, constructs lacking liposomes in hypoxic conditions exhibit a higher incidence of cells in early-stage apoptosis. In conclusion, the study demonstrates the promising potential of bioprinted oxygen-releasing liposomal scaffolds to protect ovarian stromal cells in hypoxic environments. These innovative scaffolds not only offer protection but also recapitulate the mechanical differences between the medulla and the cortex in the normal ovary structure. This opens new avenues for advanced ovary tissue engineering and transplantation strategies.

Optimizing Decellularization of Bovine Ovarian Tissue: Toward a Transplantable Artificial Ovary Scaffold with Minimized Residual Toxicity and Preserved Extracellular Matrix Morphology.

INTRODUCTION: The decellularized extracellular matrix (dECM) from ovarian tissue could be the best scaffold for the development of a transplantable artificial ovary. Typically, dECM from ovarian tissue has been obtained using sodium dodecyl sulfate (SDS), at a concentration of 1% for 24 h. However, SDS can leave residues in the tissue, which may be toxic to the seeded cells. This study aimed to obtain dECM from bovine ovarian tissue using SDS and NaOH at a minimum concentration in the shortest incubation time. METHODS: The respective SDS and NaOH concentrations investigated were 1% and 0.2M; 0.5% and 0.1M; 0.1% and 0.02M, and 0.05% and 0.01M, with 24, 12, and 6 h incubation periods. After the incubation time the tissue was washed in 50 mL of distilled water for 6 h. RESULTS: Histological analysis confirmed decellularization and showed the conservation of collagen fibers in all samples following treatment. Furthermore, the lowest SDS and NaOH concentrations that showed no DNA remaining during electrophoresis analysis were 0.1% and 0.02M when incubated for 24 and 12 h. DNA quantification resulted in ˂ 0.2 ng DNA/mg ovarian tissue using these protocols. Additionally, the coculture of dECM (obtained by 0.1% SDS and 0.02M NaOH for 12 h) with ovarian cells showed that there was no toxic effect for the cells for up to 72 h. CONCLUSION: The protocol involving 0.1% SDS and 0.02M NaOH for 12 h incubation decellularizes bovine ovarian tissue, generating a dECM that preserves the native ECM morphology and is non-toxic to ovarian cells.

Influence of ovarian stromal cells on human ovarian follicle growth in a 3D environment.

STUDY QUESTION: Do ovarian stromal cells (OSCs) influence the viability and growth of human preantral follicles in vitro? SUMMARY ANSWER: A feeder layer of OSCs promotes the growth and transition of low developmental stage follicles to the primary/secondary stage while maintaining a high proportion of viable follicles. WHAT IS KNOWN ALREADY: In the ovary, follicles rely on the support of ovarian cells, which secrete essential factors for their survival and development. This phenomenon has also been demonstrated in vitro through the 3D culture of isolated mouse primary and secondary follicles on a feeder layer of OSCs. This co-culture notably enhances follicle survival and growth. STUDY DESIGN SIZE DURATION: Pre-antral follicles were isolated from human frozen-thawed ovarian tissue biopsies and then encapsulated in 1% alginate scaffolds. These embedded preantral follicles were either placed directly on the OSCs feeder layer or at the bottom of a culture dish for a 7-day in vitro culture (control). The study compared follicle viability, growth, and hormone production between the different groups. PARTICIPANTS/MATERIALS SETTING METHODS: Primordial/intermediate and primary follicles were isolated from frozen-thawed ovarian tissue of cancer patients (n = 6). OSCs were then isolated from ovarian tissue of post-menopausal women and cultured as a feeder layer. Follicle diameter was measured on Days 0 and 7 using an inverted microscope to assess their development based on the increase in diameter. Viability was evaluated by staining a subset of follicles (n = 87) with calcein AM and ethidium homodimer-I, followed by classification into healthy/minimally damaged and damaged/dead follicles using confocal fluorescence microscopy. Additionally, estradiol levels were measured using ELISA. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 382 human preantral follicles (370 primordial/intermediate and 12 primary) with a mean diameter of 40.8 ± 9.9 µm (mean ± SD) were isolated, embedded in 1% alginate hydrogel, and placed either on a monolayer of OSCs or directly on the plastic. By Day 7, the preantral follicles showed a significant size increase under both culture conditions (P < 0.0001 for D0 vs D7). The mean diameter of follicles (quiescent and growing) cultured on the feeder layer was 80.6 ± 11.0 µm compared to 67.3 ± 7.2 µm without it (P = 0.07). During the 7-day in vitro culture, the viability of the follicles significantly decreased only in the group without an OSCs monolayer compared to the D0 viability (P < 0.05). Additionally, more follicles transitioned to a higher developmental stage in the presence of OSCs (D0 primordial/intermediate: 184, primary: 7 vs D7 primordial/intermediate: 51, primary/secondary: 93) compared to those cultured without OSCs (D0 primordial/intermediate: 186, primary: 5 vs D7 primordial/intermediate: 84, primary/secondary: 65; P < 0.001). Specifically, 66 and 44 follicles reached the secondary stage (75< x <200 µm) in the presence and absence of OSCs, respectively. Moreover, the estradiol level was significantly higher (P = 0.006) in the alginate beads containing primordial and growing follicles cultured on the OSCs (54.1 ± 14.2 pg/ml) compared to those cultured without OSCs (29.9 ± 4.0 pg/ml). LARGE SCALE DATA: N/A. LIMITATIONS REASONS FOR CAUTION: This study was conducted using a short-term culture, and none of the primordial/intermediate/primary follicles reached the antral stage. Further in vitro studies are required to investigate follicular developmental capacity, physiology, and steroidogenesis in alginate scaffolds with human OSCs. WIDER IMPLICATIONS OF THE FINDINGS: Activating and growing human primordial/intermediate follicles to a secondary stage in in vitro short-term culture has posed a longstanding challenge. However, co-culturing with human OSCs has shown the potential to overcome this limitation. STUDY FUNDING/COMPETING INTERESTS: This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (FNRS-PDR Convention grant number T.0004.20 awarded to C.A.A., PhD scholarship awarded to H.V.), Fondation Louvain (awarded to C.A.A.; PhD scholarship awarded to S.M., as part of a legacy from Mr Frans Heyes, and PhD scholarship awarded to A.D. as part of a legacy from Mrs Ilse Schirmer), Foundation Against Cancer (grant 2018-042 awarded to A.C.), and the European Community Structural Funds and Lithuanian Research Council (Agreement registration No. D-19-0874). The authors have no conflicts of interest to declare.

In-vitro generation of follicle-like structures from human germ cell-like cells derived from theca stem cell combined with ovarian somatic cells.

BACKGROUND: The objective of this study was to induce the differentiation of human theca stem cells (hTSCs) into germ cell-like cells (hGCLCs) and assess their developmental progression following in vitro 3D culture with ovarian somatic cells within the follicle-like structures. To achieve this, the hTSCs were isolated from small antral follicles of three patients of varying ages and were then seeded in a differentiation medium for 40 days. The differentiated hGCLCs were subsequently aggregated with somatic ovarian cells (cumulus cells and hTSCs) in a ratio of 1:10 and cultured in a growth medium in a suspension culture dish. In addition to examining the morphologies, sizes, and viabilities of the differentiated hGCLCs, this study also analyzed the expression of DAZL and GDF9 proteins within the follicle-like structures. RESULTS: After 12 days, the hTSCs began to differentiate into hGCLCs, with their shapes changing from spindle-shaped to spherical. The sizes of hGCLCs increased during the differentiation period (from 25 µm to 50 µm). The survival rate of the hGCLCs after differentiation and in vitro development in primordial follicle-like structures was 54%. Unlike hTSCs, which did not express the DAZL protein, the hGCLCs and follicle-like structures successfully expressed DAZL protein (P-value < 0.05). However, hGCLCs poorly expressed the GDF9 protein. Further, the culture of hGCLCs in primordial follicle-like structures significantly increased GDF9 expression (P-value < 0.05). CONCLUSION: In conclusion, our study demonstrated that 3D cultures with ovarian somatic cells in follicle-like structures caused the successful differentiation of reproducible hGCLCs from hTSCs derived from three patients of different ages. Moreover, this method not only enhanced the in vitro development of hGCLCs but also presented a novel approach for co-culturing and developing in vitro oocyte like cells, ultimately leading to the production of artificial follicles.

Liposomal oxygen-generating hydrogel for enhancing cell survival under hypoxia condition.

The inadequate oxygen supply to engineered tissues has been a persistent challenge in tissue engineering and regenerative medicine. To overcome this limitation, we developed a scaffold combined with an oxygen-releasing liposomal system comprising catalase-loaded liposomes (CAT@Lip) and H2O2-loaded liposomes (H2O2@Lip). This oxygenation system has shown high cytocompatibility when they were applied to human stromal cells. Under hypoxic conditions, the cell viability enclosed in the oxygen-releasing liposomal alginate hydrogel (94.62 ± 3.46 %) was significantly higher than that of cells enclosed in hydrogel without liposomes (47.18 ± 9.68 %). There was no significant difference in cell viability and apoptosis rate compared to normoxia conditions after three days, indicating the effectiveness of the oxygen-releasing approach in hypoxic conditions. In conclusion, our study demonstrates that the use of liposomal oxygen-releasing scaffolds can overcome the oxygen diffusion challenge in tissue implant fabrication, providing a simple solution for cellular oxygenation that could be a crucial element in tissue engineering.

New Solutions for Old Problems: How Reproductive Tissue Engineering Has Been Revolutionizing Reproductive Medicine.

Acquired disorders and congenital defects of the male and female reproductive systems can have profound impacts on patients, causing sexual and endocrine dysfunction and infertility, as well as psychosocial consequences that affect their self-esteem, identity, sexuality, and relationships. Reproductive tissue engineering (REPROTEN) is a promising approach to restore fertility and improve the quality of life of patients with reproductive disorders by developing, replacing, or regenerating cells, tissues, and organs from the reproductive and urinary systems. In this review, we explore the latest advancements in REPROTEN techniques and their applications for addressing degenerative conditions in male and female reproductive organs. We discuss current research and clinical outcomes and highlight the potential of 3D constructs utilizing biomaterials such as scaffolds, cells, and biologically active molecules. Our review offers a comprehensive guide for researchers and clinicians, providing insights into how to reestablish reproductive tissue structure and function using innovative surgical approaches and biomaterials. We highlight the benefits of REPROTEN for patients, including preservation of fertility and hormonal production, reconstruction of uterine and cervical structures, and restoration of sexual and urinary functions. Despite significant progress, REPROTEN still faces ethical and technical challenges that need to be addressed. Our review underscores the importance of continued research in this field to advance the development of effective and safe REPROTEN approaches for patients with reproductive disorders.

Mind the mechanical strength: tailoring a 3D matrix to encapsulate isolated human preantral follicles.

STUDY QUESTION: Would a hydrogel with similar mechanical properties to the human ovarian cortex support preantral follicle development? SUMMARY ANSWER: Yes, our tailored PEGylated fibrin hydrogel was shown to significantly improve follicle growth in vitro. WHAT IS KNOWN ALREADY: One of the main challenges in developing an engineered ovary is to provide a 3D matrix that supports the follicle architecture and the interaction between granulosa cells and the oocyte as they are essential for folliculogenesis. Thanks to its biocompatibility and bioactivity, fibrin has been employed to fabricate a 3D matrix to encapsulate ovarian follicles. However, follicles lose their physical support within a few days owing to rapid fibrin degradation. Therefore, different strategies, including physical and chemical modifications, have been developed to enhance the stability of fibrin. STUDY DESIGN SIZE DURATION: By developing a matrix made of a synthetic (polyethylene glycol: PEG) and natural polymer (fibrin), we aimed to overcome fibrin degradation by the chemical reaction of PEGylation and tailor a PEGylated fibrin hydrogel formulation with mechanical strength similar to the ovarian cortex in women of reproductive age. To this end, response surface methodology was employed to obtain a tailored formulation of PEGylated fibrin. This hydrogel was then tested to encapsulate and support isolated human preantral follicles in vitro. PARTICIPANTS/MATERIALS SETTING METHODS: A PEGylated fibrin formulation was tailored using mathematical modeling software to mimic the mechanical properties of human ovarian tissue at reproductive age. Human preantral follicles were isolated from 11 patients of reproductive age and encapsulated in the tailored hydrogels, which were cultured in vitro for 4 or 7 days. Follicle survival and diameter were assessed on Days 1 and 7. Furthermore, the follicles were subjected to confocal microscopy to evaluate their growth (Ki67 staining) on Day 7 and analyze cell-cell communication (connexin 43 and transzonal projection staining) on Day 4. MAIN RESULTS AND THE ROLE OF CHANCE: In this study, mathematical modeling was applied to achieve the biomechanically tailored PEGylated fibrin formulation by targeting the specific goal of 3178 ± 245 Pascal, Young's modulus of ovarian cortical tissue in reproductive-age women. Our results demonstrated that the PEGylated fibrin hydrogel consisting of 39.06 mg/ml of PEGylated fibrinogen and 50.36 IU/ml of thrombin was the optimum condition with the desirability of 97.5%. This tailored hydrogel yielded a high follicle survival rate (83%) after 7 days of in vitro culture and supported its development up to the secondary stage. Follicle growth was confirmed by the presence of Ki67-positive granulosa cells on Day 7. Additionally, connexin 43 and Phalloidin staining indicated the retention of connections between granulosa cells and the oocyte. LARGE SCALE DATA: N/A. LIMITATIONS REASONS FOR CAUTION: In this study, our tailored hydrogel was only tested in vitro, which is not the same as the physiological environment. It is crucial to conduct a study assessing the follicles following their encapsulation in the tailored hydrogel and transplantation, which will be the next step of our investigation. WIDER IMPLICATIONS OF THE FINDINGS: The findings from this study introduced a suitable biomaterial similar to the ovarian cortex in reproductive-age women in terms of biomechanical properties for encapsulating human preantral follicles. This biomaterial allowed the radial growth of follicles and preserved their viability. Furthermore, PEGylation improved the stability of fibrin and the physical support of follicles. STUDY FUNDING/COMPETING INTERESTS: This study was supported by grants from the Fondation Louvain (PhD scholarship awarded to S.M., as part of a legacy from Mr Frans Heyes, and PhD scholarship awarded to A.D. as part of a legacy from Mrs Ilse Schirmer). The authors declare no competing interests.

Cancer cell contamination and decontamination methods for ovaries and testes: special focus on prepubertal gonads with a view to safe fertility restoration.

Fertility restoration in patients that survived a hematological cancer during childhood is a core part of their care pathway. Nonetheless, there might be a risk of contamination of the gonads by cancer cells, especially in patients presenting with leukemia and lymphoma. When only a few cancer cells have reached the gonad, they may not be detected by routine histological examination, and therefore more sensitive techniques are required before being confident of the safety of transplanting cryostored testicular and ovarian tissues or cells back to the patient after recovery. Furthermore, if neoplastic cells are identified in the gonadal tissue, methods to eliminate such cells are urgently awaited as the presence of only a few cancer cells may induce disease relapse in these patients. In this review, contamination rates of human gonadal tissue in the case of leukemia or lymphoma as well as decontamination methods applied to both adult and prepubertal testicular and ovarian tissues are presented. Prepubertal gonads will be the main focus as we aim to show how far we have come in establishing safe approaches to fertility restoration. Advances have been made using animal tissue that is usually artificially contaminated by the addition of cancer cell lines to the gonadal cells or tissue, but these techniques need to be improved and still await development in the case of in vivo cancer cell invasion of tissue.

Co-culture of human cryopreserved fragmented ovarian tissue with theca progenitor cells derived from theca stem cells.

PURPOSE: Despite the significant advances in the in vitro development of human primordial follicles, it is still a challenging approach with great potential for improvements. Therefore, the present study aimed to investigate the effect of a feeder layer of human theca progenitor cells (hTPCs) on the development of primordial follicles embedded in human ovarian tissue. METHODS: Fragments of frozen-thawed ovarian tissue were activated using the vanadate-derivative dipotassium bisperoxo (5-hydroxy-pyridine-2-carboxylic) oxovanadate (V) and kit ligand for 24 h. Then, the specimens were divided into the co-culture and mono-culture groups and were cultured with and without a hTPC feeder layer for 6 days, respectively. Afterward, the follicles were counted and classified, and the hormone levels and expression levels of apoptosis- and folliculogenesis-related genes were assessed. RESULTS: Both culture groups showed significant follicle growth (P < 0.05). However, the co-culture group had a significantly higher number of growing follicles compared to the other group (P < 0.05). Moreover, the expression levels of ZP1, ZP2, ZP3, BMP-7, AMH, and GDF9 were significantly higher in the co-culture group compared to the other group (P < 0.05), while the expression levels of P53 and CASP3 were significantly lower (P < 0.05). Also, the concentrations of estradiol, progesterone, testosterone, and androstenedione were significantly higher in the co-culture group compared to the other group (P < 0.05). CONCLUSION: The present study results provided novel evidence on the direct role of hTPCs in the growth and development of human primordial follicles. However, there is a need for future studies to illustrate the underlying mechanisms. Schematic summary of the results. According to our results, the expression of ZP1, ZP2, ZP3, and GDF9 in the oocytes, AMH in the granulosa cells, and BMP4 in the theca cells of the co-culture group were significantly higher than those of the mono-culture and non-culture groups, while the expression of apoptotic genes (BAX, CASP3, and P53) was significantly lower. Moreover, the co-culture group showed significantly increased levels of estradiol, progesterone, testosterone, and androstenedione in its culture media compared to the mono-culture groups.

Ex vivo purging of cancer cells from ovarian tissue using photodynamic therapy: a novel strategy to restore fertility in leukemia patients.

STUDY QUESTION: Is it possible to purge leukemia cells from ovarian tissue (OT) fragments before transplantation? SUMMARY ANSWER: Our photodynamic therapy (PDT) approach has been shown to efficiently destroy leukemia cells from tumor-infiltration mimicking models (TIMs), indicating the feasibility of this technique to purge OT samples. WHAT IS KNOWN ALREADY: Autotransplantation of cryopreserved OT is the most suitable option to preserve fertility for prepubertal girls and women who require immediate cancer treatment. Up until now, more than 200 live births have already been reported after OT cryopreservation and transplantation. Leukemia is the 12th most common cancer in Europe among prepubertal girls and women of reproductive age and in 2020, the estimated number of new leukemia cases was higher than 33 000 in girls between 0 and 19 years old. Unfortunately, once their health has been restored, autotransplantation of cryopreserved OT for leukemia patients is not advised due to the high risk of transferring malignant cells back to the patient leading to leukemia recurrence. STUDY DESIGN SIZE DURATION: To safely transplant the OT from leukemia patients and restore their fertility, our goal was to develop a PDT strategy to eliminate leukemia ex vivo. To this end, we designed OR141-loaded niosomes (ORN) to create the most effective formulation for ex vivo purging of acute myelogenous leukemia cells from OT fragments (n = 4). Moreover, to ensure that such treatments are not harmful to follicle survival and development so they can be deemed a potential fertility restoration alternative, the effect of the ORN-based PDT purging procedure on follicles was assessed after xenografting the photodynamic-treated OT in SCID mice (n = 5). The work was carried out between September 2020 and April 2022 at the Catholic University of Louvain. PARTICIPANTS/MATERIALS SETTING METHODS: After establishing the best ORN formulation, our PDT approach was used to eradicate HL60 cells from ex vivo TIMs prepared by microinjection of a cancer cell suspension into OT fragments. The purging efficiency was analyzed by droplet digital polymerase chain reaction and immunohistochemical analyses. Additionally, we evaluated the effect of ORN-based PDT on follicle density, survival and development, and tissue quality in terms of fibrotic areas and vascularization after 7-day xenotransplantation to immunodeficient mice. MAIN RESULTS AND THE ROLE OF CHANCE: The ex vivo purging of TIMs demonstrated that our PDT strategy could selectively eradicate the malignant cells from tissue fragments without affecting OT normal cells, as evidenced by PCR and immunohistochemical analysis. Regarding the effect of our PDT approach on follicle population and OT quality, our results after xenotransplantation revealed no significant difference between the follicle density of control (non-treated, grafted OT) and PDT-treated groups (2.38 ± 0.63 and 3.21 ± 1.94 morphologically normal follicles/mm2, respectively). In addition, our findings showed that the control and PDT-treated OT could be equally vascularized (7.65 ± 1.45% and 9.89 ± 2.21%, respectively). Similarly, the proportions of fibrotic area did not differ between the control (15.96 ± 5.94%) and PDT-treated groups (13.32 ± 3.05%). LARGE SCALE DATA: N/A. LIMITATIONS REASONS FOR CAUTION: This study did not use OT fragments from leukemia patients, but TIMs created after injection of HL60 cells into OT from healthy patients. Therefore, while the results are promising, whether our PDT approach will be equally successful in eliminating malignant cells from leukemia patients remains to be assessed. WIDER IMPLICATIONS OF THE FINDINGS: Our results showed that the purging procedure causes no significant impairment effect on follicle development and tissue quality, suggesting that our novel PDT procedure could be a promising strategy to destroy leukemia cells in fragments of OT, allowing safe transplantation in cancer survivors. STUDY FUNDING/COMPETING INTERESTS: This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (FNRS-PDR Convention grant number T.0004.20 awarded to C.A.A.); Fondation Louvain (awarded to C.A.A.; a Ph.D. scholarship awarded to S.M., as part of a legacy from Mr Frans Heyes, and a Ph.D. scholarship awarded to A.D. as part of a legacy from Mrs. Ilse Schirmer); and Foundation Against Cancer (grant number 2018-042 awarded to A.C.). The authors declare no competing interests.

Rescuing fertility during COVID-19 infection: exploring potential pharmacological and natural therapeutic approaches for comorbidity, by focusing on NLRP3 inflammasome mechanism.

The respiratory system was primarily considered the only organ affected by Coronavirus disease 2019 (COVID-19). As the pandemic continues, there is an increasing concern from the scientific community about the future effects of the virus on male and female reproductive organs, infertility, and, most significantly, its impact on the future generation. The general presumption is that if the primary clinical symptoms of COVID-19 are not controlled, we will face several challenges, including compromised infertility, infection-exposed cryopreserved germ cells or embryos, and health complications in future generations, likely connected to the COVID-19 infections of parents and ancestors. In this review article, we dedicatedly studied severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) virology, its receptors, and the effect of the virus to induce the activation of inflammasome as the main arm of the innate immune response. Among inflammasomes, nucleotide oligomerization domain-like receptor protein, pyrin domain containing 3 (NLRP3) inflammasome pathway activation is partly responsible for the inflicted damages in both COVID-19 infection and some reproductive disorders, so the main focus of the discussion is on NLRP3 inflammasome in the pathogenesis of COVID-19 infection alongside in the reproductive biology. In addition, the potential effects of the virus on male and female gonad functions were discussed, and we further explored the potential natural and pharmacological therapeutic approaches for comorbidity via NLRP3 inflammasome neutralization to develop a hypothesis for averting the long-term repercussions of COVID-19. Since activation of the NLRP3 inflammasome pathway contributes to the damage caused by COVID-19 infection and some reproductive disorders, NLRP3 inflammasome inhibitors have a great potential to be considered candidates for alleviating the pathological effects of the COVID-19 infection on the germ cells and reproductive tissues. This would impede the subsequent massive wave of infertility that may threaten the patients.

The characterization and therapeutic applications of ovarian theca cells: An update.

Theca cells perform a range of roles during folliculogenesis. So far, little is known about their recruitment process and function since early research has mainly focused on the interactions between granulosa cells and the oocyte, leaving theca cells unfairly forgotten in the understanding of ovarian physiology and pathogenesis. Given that research on theca cells has greatly emerged in recent years, this review of literature aims to discuss the established theoretical concepts with the most recent findings about theca cells' characterization and origins, in vitro culture applications as models for fertility preservation and pharmacological/toxicological studies, its importance in unraveling pathogenic pathways, and stem-cell-based bioengineering for hormonal replacement therapies. Isolation and in vitro culture techniques for theca cells have led to essential advancements in their characterization as a specific cell population. Unraveling the origins of theca cells during the in vivo differentiation process in the adult ovary will assist the development of hormonal replacement therapies, reestablishment of fertility, and treatments for diseases such as premature ovarian insufficiency and polycystic ovarian syndrome, which seem to be directly influenced by theca cells.

Medium supplementation can influence the human ovarian cells in vitro.

BACKGROUND: Cells are an essential part of the triple principles of tissue engineering and a crucial component of the engineered ovary as they can induce angiogenesis, synthesize extracellular matrix and influence follicle development. Here, we hypothesize that by changing the medium supplementation, we can obtain different cell populations isolated from the human ovary to use in the engineered ovary. To this end, we have in vitro cultured cells isolated from the menopausal ovarian cortex using different additives: KnockOut serum replacement (KO), fetal bovine serum (FBS), human serum albumin (HSA), and platelet lysate (PL). RESULTS: Our results showed that most cells soon after isolation (pre-culture, control) and cells in KO and FBS groups were CD31- CD34- (D0: vs. CD31-CD34+, CD31 + CD34+, and CD31 + CD34- p < 0.0001; KO: vs. CD31-CD34+, CD31 + CD34+, and CD31 + CD34- p < 0.0001; FBS: vs. CD31-CD34+ and CD31 + CD34+ p < 0.001, and vs. CD31 + CD34- p < 0.01). Moreover, a deeper analysis of the CD31-CD34- population demonstrated a significant augmentation (more than 86%) of the CD73+ and CD90+ cells (possibly fibroblasts, mesenchymal stem cells, or pericytes) in KO- and FBS-based media compared to the control (around 16%; p < 0.001). Still, in the CD31-CD34- population, we found a higher proportion (60%) of CD90+ and PDPN+ cells (fibroblast-like cells) compared to the control (around 7%; vs PL and KO p < 0.01 and vs FBS p < 0.001). Additionally, around 70% of cells in KO- and FBS-based media were positive for CD105 and CD146, which may indicate an increase in the number of pericytes in these media compared to a low percentage (4%) in the control group (vs KO and FBS p < 0.001). On the other hand, we remarked a significant decrease of CD31- CD34+ cells after in vitro culture using all different medium additives (HSA vs D0 p < 0.001, PL, KO, and FBS vs D0 P < 0.01). We also observed a significant increase in epithelial cells (CD326+) when the medium was supplemented with KO (vs D0 p < 0.05). Interestingly, HSA and PL showed more lymphatic endothelial cells compared to other groups (CD31 + CD34+: HSA and PL vs KO and FBS p < 0.05; CD31 + CD34 + CD90 + PDPN+: HSA and PL vs D0 p < 0.01). CONCLUSION: Our results demonstrate that medium additives can influence the cell populations, which serve as building blocks for the engineered tissue. Therefore, according to the final application, different media can be used in vitro to favor different cell types, which will be incorporated into a functional matrix.

Photodynamic therapy using OR141-loaded nanovesicles for eradication of leukemic cells from ovarian tissue.

In 2020, the estimated number of new leukemia cases was higher than 30,000 in girls between 0 and 19 years old. Due to cancer treatment, some of these patients may lose both endocrine and reproductive functions. Transplantation of cryopreserved ovarian tissue is not advised after cancer remission because it has a high risk of reintroducing malignant cells in the patient, potentially leading to leukemia recurrence. To safely transplant the ovarian tissue from these patients and restore their fertility, our goal was to develop a photodynamic therapy (PDT) strategy to eliminate leukemia ex vivo. To this end, we designed, optimized, and characterized OR141-loaded niosomes (ORN) to develop the most effective formulation for ex vivo purging ovarian fragments from chronic myelogenous leukemia cells. After establishing the best ORN formulation, the PDT efficiency of optimized ORN was determined for human ovarian stromal cells and acute myeloid leukemia cell line (HL60). Blank niosomes treatment on ovarian stromal cells causes no significant toxicity, showing that the composition of the nanoparticle is not toxic. On the other hand, the in vitro studies showed that while ovarian stromal cells were still viable (82.04 ± 2.79%) after the treatment by 0.5 µM ORN, the same treatment yielded 95.43 ± 3.89% toxicity and cell death in the cancer cells. In conclusion, our results showed that our novel PDT procedure could be a promising strategy to destroy leukemia cells in ovarian tissue fragments allowing safe transplantation in cancer survivors.

Nanoemulsion applications in photodynamic therapy.

Nanoemulsion, or nanoscaled-size emulsions, is a thermodynamically stable system formed by blending two immiscible liquids, blended with an emulsifying agent to produce a single phase. Nanoemulsion science has advanced rapidly in recent years, and it has opened up new opportunities in a variety of fields, including pharmaceuticals, biotechnology, food, and cosmetics. Nanoemulsion has been recognized as a potential drug delivery technology for various drugs, such as photosensitizing agents (PS). In photodynamic therapy (PDT), PSs produce cytotoxic reactive oxygen species under specific light irradiation, which oxidize the surrounding tissues. Over the past decades, the idea of PS-loaded nanoemulsions has received researchers' attention due to their ability to overcome several limitations of common PSs, such as limited permeability, non-specific phototoxicity, hydrophobicity, low bioavailability, and self-aggregation tendency. This review aims to provide fundamental knowledge of nanoemulsion formulations and the principles of PDT. It also discusses nanoemulsion-based PDT strategies and examines nanoemulsion advantages for PDT, highlighting future possibilities for nanoemulsion use.

Secure transplantation by tissue purging using photodynamic therapy to eradicate malignant cells.

The field of photodynamic therapy (PDT) for treating various malignant neoplasms has been given researchers' attention due to its ability to be a selective and minimally invasive cancer therapy strategy. The possibility of tumor cell infection and hence high recurrence rates in cancer patients tends to restrict autologous transplantation. So, the photodynamic tissue purging process, which consists of selective photoinactivation of the malignant cells in the graft, is defined as a compromising strategy to purify contaminated tissues before transplantation. In this strategy, the direct malignant cells' death results from the reactive oxygen species (ROS) generation through the activation of a photosensitizer (PS) by light exposure in the presence of oxygen. Since new PS generations can effectively penetrate the tissue, PDT could be an ideal ex vivo tissue purging protocol that eradicates cancer cells derived from various malignancies. The challenge is that the applied pharmacologic ex vivo tissue purging should efficiently induce tumor cells with minor influence on normal tissue cells. This review aims to provide an overview of the current status of the most effective PDT strategies and PS development concerning their potential application in ex vivo purging before hematopoietic stem cell or ovarian tissue transplantation.

Experiences of young girls and women undergoing ovarian tissue cryopreservation: a systematic review and thematic synthesis.

The aim of this study was to explore the experiences of young girls and women who underwent or considered ovarian tissue cryopreservation (OTC) using a systematic review of qualitative studies with thematic synthesis framework. Major electronic databases: MEDLINE, EMBASE, the Cochrane Library, CINAHL and PsycINFO were searched from 1946 to May 2020 and reference lists of relevant articles were hand searched. Any studies that described a qualitative inquiry and highlighted the experiences of women with regards to OTC were included. Two independent reviewers screened the title and abstracts and made a selection against inclusion criteria. Main outcomes measures were experiences of women who have considered and/or undergone OTC, decision making in women who underwent or considered OTC and patient education. Nineteen studies were assessed for full text eligibility and four were included in analysis. 144 verbatim quotations from 85 participants in high income countries (UK, USA and Denmark) were included. Two studies adopted grounded theory approach, one phenomenology and one inductive content analysis. Four themes were generated; participants described their experiences as emotional, involving complex decision-making, helping them prepare for the long-term consequences of potentially losing their fertility and hormonal function, as well as their experience being educational. Additionally, the more practical aspects of the procedure such as OTC being invasive as well as costs implications were highlighted. Women and young girls are often involved in making time-sensitive decisions whether or not to undergo OTC. Healthcare professionals involved in the care of young girls and women undergoing this method need to also take into consideration the emotional wellbeing of the patients as well as the time and expertise it requires to help them make an informed decision.

Safety of Lavender Oil-Loaded Niosomes for In Vitro Culture and Biomedical Applications.

(1) Background: Essential oils have long been used as therapeutic agents. Lavender (Lavandula angustifolia) oil (LO) is an antispasmodic, anticonvulsant, relaxant, painkilling, and antimicrobial essential oil investigated as a natural substance for biomedical therapies. Nanoparticles have shown significant promise in improving drug delivery and efficacy. Considering these benefits, the aim of this study was to evaluate the toxicity of LO and lavender oil niosomes (LONs) in stem cells and myofibroblast models cultured in vitro. (2) Methods: Adipose tissue-derived stem cells and myometrial cells were cultured with LO or LONs at different concentrations (0, 0.016%, 0.031%, and 0.063%) and toxicity was evaluated with PrestoBlue™ and live/dead assay using calcein and ethidium homodimer. (3) Results: Cell viability was similar to controls in all groups, except in 0.063% LO for myometrial cells, which showed lower viability than the control medium. (4) Conclusion: These results suggest that both LO and LONs are safe for cell culture and may be used for pharmaceutical and biomedical therapies in future applications in regenerative medicine.