Sang hwan Hyun

• DVM PhD
• Professor at Chungbuk National University, Cheongju, Chungbuk, South Korea

Introduction Embryo cryopreservation is a valuable technique used for preserving genetic resources for long periods. However, the survival rate of embryos is dependent on the method used. Therefore, in this study, we evaluated the efficiency of slow freezing method but with an additional dehydration step prior to freezing to overcome the formation...

Neuromuscular diseases (NMDs) are a genetically or clinically heterogeneous group of diseases that involve injury or dysfunction of neuromuscular tissue components, including peripheral motor neurons, skeletal muscles, and neuromuscular junctions. To study NMDs and develop potential therapies, remarkable progress has been made in generating in vitr...

Tetraploid complementation is an ideal method for demonstrating the differentiation potential of pluripotent stem cells. In this study, we selected the most efficient tetraploid production method for porcine embryos and investigated whether tetraploid blastomere aggregation could enhance the quality of tetraploid embryos. Three methods were investi...

Stem cell factor (SCF), a cytokine growth factor, is expressed in various tissues of the male and female reproductive organs, including the testis, ovary, and endometrium. Its primary function involves cell survival, differentiation, and proliferation, achieved through its binding to the c-kit receptor. This study aimed to scrutinize the effects of...

In vitro generation of porcine embryos is an indispensable method in the realms of both agriculture and biomedicine. Nonetheless, the extant procedures encounter substantial obstacles pertaining to both the caliber and efficacy of the produced embryos, necessitating extensive research to in vitro maturation (IVM), the seminal commencement phase. On...

Copper (Cu) ions have redox activity and act as cofactors of enzymes related to respiration, radical detoxification, and iron metabolism. In this study, we aimed to examine the effects of copper (II) chloride dihydrate (CuCl2$2H2O) on porcine oocytes during in vitro maturation (IVM) and subsequent embryonic development following parthenogenetic act...

Introduction Liquid preservation of boar semen is a highly preferred method for semen preservation in pig production. However, oxidative stress is the main challenge during the liquid preservation of boar semen in a time dependent manner. Therefore, supplementation of sperm with antioxidants during storage to protect them from oxidative stress has...

Neurotrophin-4 (NT-4), a neurotrophic factor, appears to affect early embryonic development because it is secreted not only by neurons but also by oviductal and uterine epithelial cells. However, no studies have characterized the effects of NT-4 on early embryonic development in pigs. In this study, we applied the experimental model of parthenogene...

Background: Genetically modified pigs are considered ideal models for studying human diseases and potential sources for xenotransplantation research. However, the somatic cell nuclear transfer (SCNT) technique utilized to generate these cloned pig models has low efficiency and fetuses exhibit limited developmental potential for abnormalities in the...

The efficiency of somatic cell nuclear transfer (NT) in pigs is low and requires enhancement. We identified the most efficient method for zona pellucida (ZP) removal and blastomere aggregation in pigs and investigated whether the aggregation of NT and parthenogenetic activation (PA) of blastomeres could reduce embryonic apoptosis and improve the qu...

Simple Summary This study investigated the effect of various growth factors and hormones in an in vitro growth medium on in vitro maturation and the developmental competence of oocytes derived from small antral follicles in pigs. Cumulus–oocyte complexes derived from small antral follicles (<3 mm) were cultured in an in vitro growth medium suppleme...

Porcine embryos are used for a variety of applications. However, the maturation rate in vitro remains low, and novel in vitro maturation (IVM) techniques that facilitate the collection of mature oocytes are necessary. C-C motif chemokine ligand 2 (CCL2) is a key periovulatory chemokine present in cumulus-oocyte complexes (COCs). We aimed to examine...

Background: Ergothioneine (EGT) is a natural amino acid derivative in various animal organs and is a bioactive compound recognized as a food and medicine. Objectives: This study examined the effects of EGT supplementation during the in vitro maturation (IVM) period on porcine oocyte maturation and subsequent embryonic development competence afte...

Interleukin-7 (IL-7), a vital factor that affects cell development, proliferation, and survival, plays an important role in oocyte maturation. However, its role in embryonic development remains unknown. Therefore, in this study, we aimed to investigate the effects of IL-7 supplementation on in vitro culture (IVC) of porcine embryos after parthenoge...

Aggregation of blastomeres is a promising method to improve the developmental competence of blastocysts and may be useful for the production of chimeric animals and the establishment of embryonic stem cell lines by increasing inner cell masses. Here, we determined the optimal conditions for blastomere aggregation using phytohemagglutinin-L (PHA-L)...

The trace element Cu is required for the activity of various enzymes essential for physiological processes. In this study, we elucidated the copper transport system in porcine follicular cells and investigated the effect of Cu chelation during in vitro maturation (IVM) of porcine oocytes and subsequent embryonic development after parthenogenetic ac...

Pigs are cost-effective industrial animals because they produce a large number of offspring and have shorter rebreeding intervals compared with other animals, such as non-human primates. The reproductive physiology of pigs has been studied over the past several decades. However, there is not enough research on the effects of the neurotrophic factor...

Neurotrophin-4 (NT-4), a granulosa cell-derived factor and a member of the neurotrophin family, is known to promote follicular development and oocyte maturation in mammals. However, the physiological and functional roles of NT-4 in porcine ovarian development are not yet known. The aim of this study was to investigate the physiological role of NT-4...

Exposure to neurodevelopmental toxicants can cause permanent brain injury. Hance, determining the neurotoxicity of unknown substances is essential for the safety of substance. As an alternative method to animal studies, developmental neurotoxicity test (DNT) and the first discriminant function (DF) were established in previous study. This study aim...

Autophagy, an intracellular recycling system, is essential for the meiotic maturation of porcine oocytes. Multiple studies, sought to reveal the precise mechanism employed, commonly used autophagy inducers, such as rapamycin, which is a mammalian target of rapamycin (mTOR) inhibitor. However, it has a limitation as mTOR plays various roles in cell...

Background: Compared to medium containing 108 mM sodium chloride (NaCl), in vitro maturation (IVM) using a simple medium with reduced (61.6 mM) NaCl increases the cytoplasmic maturation and embryonic development of pig oocytes. Objectives: This study determines the effect of a complex medium containing reduced NaCl on the IVM and embryonic devel...

Alternative cancer models that are close to humans are required to create more valuable preclinical results during oncology studies. Here, we developed a new onco‐pig model via developing a CRISPR‐Cas9‐based Conditional Polycistronic gene expression Cassette (CRI‐CPC) system to control the tumor inducing simian virus 40 large T antigen (SV40LT) and...

ABSTRACT Objective: The present study aimed to explain the effect of fetal bovine serum (FBS) on the in vitro production of porcine embryos and the molecular effects of FBS on the growing of porcine embryos. Materials and Methods: Immature porcine oocytes were matured and fertilized in vitro. The resulting zygotes were cultured in porcine zygotic...

Background Human embryonic stem cells (hESCs) transplantation had shown to provide a potential source of cells in neurodegenerative disease studies and lead to behavioral recovery in lentivirus transfected or, toxin-induced Huntington's disease (HD) rodent model. Here, we aimed to observe if transplantation of superparamagnetic iron oxide nanoparti...

Neurotrophin-4 (NT-4) is a neurotrophic factor that plays an important role in follicular development and oocyte maturation. However, it is not yet known whether NT-4 is related to oocyte maturation and follicular development in pigs. This study aims to investigate the effects of NT-4 supplementation during in vitro maturation (IVM) of porcine oocy...

Stem cell factor (SCF), also known as c-Kit ligand, plays an important role in the proliferation of primordial germ cells and the survival of oocytes during follicular development. The aim of this study was to investigate the effect of SCF/c-Kit signaling on in vitro maturation (IVM) of porcine oocytes by analyzing nuclear and cytoplasmic maturatio...

Human pluripotent stem cells (hPSCs) have attracted considerable interest in understanding the cellular fate determination processes and modeling a number of intractable diseases. In vitro generation of skeletal muscle tissues using hPSCs provides an essential model to identify the molecular functions and gene regulatory networks controlling the di...

Simple Summary Hyaluronic acid, also known as hyaluronan, is essential for the expansion of cumulus cells, the maturation of oocytes, and further embryo development. This study aimed to examine the effects of treatment with glucuronic acid and N-acetyl-D-glucosamine, which are components of hyaluronic acid, during porcine oocyte in vitro maturation...

Simple Summary Oocyte-secreted factors play an essential role in oogenesis and fertility through bidirectional crosstalk between oocytes and somatic cells. Interleukin-7, known as an oocyte-secreted factor, has recently been shown to improve oocyte developmental competence through interaction with cumulus cells around the oocytes. This study aimed...

Although the human brain would be an ideal model for studying human neuropathology, it is difficult to perform in vitro culture of human brain cells from genetically engineered healthy or diseased brain tissue. Therefore, a suitable model for studying the molecular mechanisms responsible for neurological diseases that can appropriately mimic the hu...

Simple Summary A recent mouse study reported that R-spondin2 promotes follicular development by activating WNT/Catenin beta-1 (CTNNB1) signaling in granulated cells. Our results demonstrate that RSPO2, CTNNB1, G-protein coupled receptor 4 (LGR4), and G-protein coupled receptor 5 (LGR5) factors play a major role in porcine follicular development, an...

Copper (Cu) ions have redox activity and act as cofactors of enzymes related to respiration, radical detoxification, and iron metabolism. In this study, we aimed to examine the effects of copper (II) chloride dihydrate (CuCl2·2H2O) on porcine oocytes during in vitro maturation (IVM) and subsequent embryonic development following parthenogenetic act...

Simple Summary A non-integrating and self-replicating Venezuelan equine encephalitis RNA replicon system can potentially make a great contribution to the generation of clinically applicable canine induced pluripotent stem cells. Our study shows a new method to utilize the synthetic RNA-based approach for canine somatic cell reprogramming regarding...

Background: Previous studies have reported that electrical stimulation of the motor cortex is effective in reducing trigeminal neuropathic pain; however, the effects of optical motor cortex stimulation remain unclear. Objective: The present study aimed to investigate whether optical stimulation of the primary motor cortex can modulate chronic neuro...

Background: Meningiomas are the second most common primary tumors of the central nervous system. However, there is a paucity of data on meningioma biology due to the lack of suitable preclinical in vitro and in vivo models. In this study, we report the establishment and characterization of patient-derived, spontaneously immortalized cancer cell li...

Background: Previous studies have reported that electrical stimulation of the motor cortex is effective in reducing trigeminal neuropathic pain; however, the effects of optical motor cortex stimulation remain unclear. Objective: The present study aimed to investigate whether optical stimulation of the primary motor cortex can modulate chronic neuro...

Background Previous studies have reported that electrical stimulation of the motor cortex is effective in reducing trigeminal neuropathic pain; however, the effects of optical motor cortex stimulation remain unclear. Objective The present study aimed to investigate whether optical stimulation of the primary motor cortex can modulate chronic neuropa...

Stem cell fate is largely determined by cellular signaling networks and is heavily dependent on the supplementation of exogenous recombinant proteins into culture media; however, uneven distribution and inconsistent stability of recombinant proteins are closely associated with the spontaneous differentiation of pluripotent stem cells (PSCs) and res...

Recent advances in somatic cell nuclear transfer (SCNT) in canines facilitate the production of canine transgenic models. Owing to the importance of stable and strong promoter activity in transgenic animals, we tested human elongation factor 1α (hEF1α) and cytomegalovirus (CMV) promoter sequences in SCNT transgenic dogs. After transfection, transge...

Canine cloning is occasionally accompanied by abnormal sexual development. Some male donor cells produce cloned pups with female external genitalia and complete male gonadal dysgenesis, which is classified as an XY disorder of sex development (XY DSD). In this study, we examine the potential of 5-aza-2'-deoxycytidine (5-aza-dC), a DNA methyltransfe...

Granulocyte-colony stimulating factor (G-CSF), a pleiotropic cytokine, belongs to the hematopoietic growth factor family. Recent studies have reported that G-CSF is a predictive biomarker of oocyte and embryo developmental competence in humans. The aim of our study was to determine whether CSF3 and its receptor (CSF3R) were expressed in porcine mat...

Objective: No optimum genetic rat Huntington model both neuropathological using an adeno-associated virus (AAV-2) vector vector has been reported to date. We investigated whether direct infection of an AAV2 encoding a fragment of mutant huntingtin (AV2-82Q) into the rat striatum was useful for optimizing the Huntington rat model. Methods: We pre...

Objective: The role of the nucleus accumbens (NAc) in chronic neuropathic pain has been suggested, but the role of the NAc in dorsal root ganglion (DRG) neuropathic pain remains unclear. The objective of this study was to determine whether optogenetic stimulation of the NAc influences DRG compression-induced neuropathic pain. Materials and method...

Autophagy is a critical process in early mammalian embryogenesis. Mammalian target of rapamycin (mTOR) inhibitors are major regulators of autophagy. However, mTOR plays a vital role in major signaling pathways controlling cell growth and metabolism; thus, more secure autophagy activation methods should be considered. The present study investigated...

Chronic back pain and sciatica caused by dorsal root ganglion (DRG) compression have frequently encountered in clinical practice. DRG relay peripheral to central sensory information of pain in anatomy. Nucleus accumbens (NAc) in chronic neuropathic pain have been suggested, but the role of the NAc in DRG neuropathic pain condition remains unclear....

Objective: We investigated how pituitary adenylate cyclase-activating polypeptide (PACAP) affects on embryonic development during pre-in vitro maturation (pre-IVM) using porcine oocytes isolated from small follicles. Methods: We divided the follicles into the experimental groups by size (SF; small follicles, MF; medium follicles) and treated wit...

Despite their potential applications in future regenerative medicine, periodontal ligament stem cells (PDLSCs) are difficult to obtain in large amounts from patients. Therefore, maintaining stemness while expanding the cell numbers for medical use is the key to transitioning PDLSCs from the bench to the clinic. Lysophosphatidic acid (LPA), which is...

Growth differentiation factor 8 (GDF8), also known as myostatin, is a member of the transforming growth factor-β (TGF-β) family and has been identified as a strong physiological regulator of muscle differentiation. Recently, the functional role of GDF8 in reproductive organs has received increased interest following its detection in the human place...

Growth differentiation factor 8 (GDF8) is a member of the transforming growth factor-β family and a physiological regulator. According to recent studies, GDF8 can be detected in follicular fluid and the uterus, suggesting that GDF8 may affect preimplantation embryonic development and act in a paracrine manner to improve the success of late-blastocy...

The success of in vitro embryo production demonstrates that the oviduct can be bypassed during early embryonic development. Using an ex vivo model of porcine uterus is one of the strategies used to investigate fertilization within the oviductal environment. In this study, in vitro-matured porcine oocytes (MII) were fertilized with 7.5 × 10 ⁷ , 15 ×...

Atypical chemokine receptor (ACKR) 1, ACKR2, ACKR3, and ACKR4, chemokine decoy receptors that lack G-protein-mediated signaling pathways, internalize and degrade chemokines to control their availability and function. Chemokines play important roles in the endometrium during the estrous cycle and pregnancy, but the expression and regulation of ACKRs...

Prior to transplantation, preclinical study of safety and efficacy of neural progenitor cells (NPCs) is needed. Therefore, it is important to generate an efficient in vitro platform for neural cell differentiation in large animal models such as pigs. In this study, porcine‐induced pluripotent stem cells (iPSCs) were seeded at high cell density to a...

Background Genetic engineering technology such as clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system provides a powerful tool for developing disease models and determining gene functions. Recent interests in canine cancer models have highlighted the necessity of developing genetic engineering tools for dogs. In this stud...

Phytosphingosine-1-Phosphate (P1P) is a signaling sphingolipid regulating various physiological activities. Yet, little is known of the effect of P1P in the context of reproduction. As such, we aimed to investigate the influence of P1P on oocyte maturation during porcine in vitro maturation (IVM). Here we report the expression of S1PR1-3 among P1P...

Background The porcine brain is gyrencephalic with similar gray and white matter composition and size more comparable to the human rather than the rodent brain; however, there is lack of information about neural progenitor cells derived from this model. Results Here, we isolated GFAP-positive porcine neural stem cells (NSCs) from the brain explant...

Current research suggests that supplementing in vitro culture (IVC) media with vascular endothelial growth factor (VEGF) may have beneficial effects on the development of porcine embryos in vitro. However, the molecular signaling mechanisms underlying this effect are unclear. Therefore, we aimed to investigate the effects of VEGF on molecular signa...

Lysophosphatidic acid (LPA) is a phospholipid-derived signaling molecule with biological activities, such as stimulating cell proliferation, differentiation and migration. In the present study, we examined the effect of LPA on porcine oocytes during in vitro maturation (IVM) and subsequent embryonic development following parthenogenetic activation...

Growth differentiation factor 8 (GDF8) is a member of the transforming growth factor-β that has been identified as a strong physiological regulator. The purpose of this study was to investigate the effects of GDF8 on porcine oocytes during in vitro maturation (IVM). We investigated specific gene transcription levels in oocytes and cumulus cells (CC...

Alpha lipoic acid (ALA) is a biological membranes compound. As the antioxidant, it decreases the oxidized forms of other antioxidant substances such as vitamin C, vitamin E, and glutathione (GSH). To examine the effect of ALA on the in vitro maturation (IVM) of porcine oocytes, we investigated intracellular GSH and reactive oxygen species (ROS) lev...

Transgenic (TG) pigs are an important model for biomedical research, including disease modeling, pharmaceutical toxicity testing, and regenerative medicine. Here, we constructed 2 vector systems using the promoter of the pig glial fibrillary acidic protein (pGFAP) gene, which is an astrocyte cell marker. We established donor TG fibroblasts with pGF...

Cortisol is a steroid hormone essential to the maintenance of homeostasis that is released in response to stress and low blood glucose concentration. Cortisol is converted from cortisone by 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1). It has been reported that too much cortisol or overexpression of HSD11B1 induces obesity and the insulin resi...

Inhibitor of DNA binding (ID) proteins, ID1, ID2, ID3, and ID4 are transcriptional regulators that have a helix-loop-helix (HLH) domain but not a basic DNA binding domain. ID proteins inhibit the functions of basic HLH transcription factors and regulate cell proliferation and differentiation. However, the expression and function of ID1, ID2, ID3, a...

Background Somatic cell nuclear transfer (SCNT) is a useful biotechnological tool for transgenic animal production using genetically modified somatic cells (GMSCs). However, there are several limitations preventing successful transgenic animal generation by SCNT, such as obtaining proper somatic donor cells with a sufficiently long life span and pr...

Compared with the in vivo environment, porcine in vitro embryo-culture systems are suboptimal, as they induce oxidative stress via the accumulation of reactive oxygen species (ROS). High ROS levels during early embryonic development cause negative effects, such as apoptosis. In this study, we examined the effects of the antioxidant carboxyethylgerm...

The objective of this study was to determine the effect of fructose that was supplemented to a chemically defined in Vitro maturation (IVM) medium on oocyte maturation and embryonic development after parthenogenesis in pigs. The base medium for in Vitro maturation (IVM) was porcine zygote medium (PZM) that was supplemented with 0.05% (w/v) polyviny...

Canine oocytes ovulated at prophase complete meiosis and continue to develop in presence of a high progesterone concentration in the oviduct. Considering that meiotic competence of canine oocyte is accomplished in the oviductal environment, we postulate that hormonal milieu resulting from the circulating progesterone concentration may affect oocyte...

This study was conducted to determine the effects of biophoton treatment during in vitro maturation (IVM) and/or in vitro culture (IVC) on oocyte maturation and embryonic development in pigs. An apparatus capable of generating homogeneous biophoton energy emissions was placed in an incubator. Initially, immature pig oocytes were matured in the biop...

Growth Differentiation Factor 8 (GDF8) is a member of the transforming growth factor-β (TGF-β) family and has been identified as a strong physiological regulator. This factor is expressed as a paracrine factor in mural granulosa cells. To investigate the effects of GDF8 on the in vitro maturation (IVM) of porcine oocytes, we assessed the quality of...

Contents This study investigated the effects of early induction of autophagy on embryonic development in pigs. For this, oocytes or embryos were treated with an autophagy inducer, rapamycin (RP), during post‐activation (Pa), in vitro fertilization (IVF) and/or in vitro culture (IVC). When parthenogenesis (PA) embryos were untreated (control) or tre...

This study determined the effects of postactivation treatment with demecolcine and/or 6-dimethylaminopurine (6-DMAP) on in vivo and in vitro developmental competence of somatic cell nuclear transfer (SCNT) embryos in pigs. SCNT embryos were treated for 4 hours with 0.4??g/mL demecolcine, 2?mM 6-DMAP, or both after electric activation, then transfer...

Zeaxanthin is a common carotenoid, which is a powerful antioxidant that protects against damage caused by reactive oxygen species. The aim of the present study was to investigate the effects of zeaxanthin supplementation on in vitro maturation of porcine embryo development. We investigated nuclear maturation, intracellular glutathione (GSH), and re...

Although several cloned pigs have been successfully produced, the developmental competence of cloned embryos in vitro is still very low. Granulocyte colony-stimulating factor receptor (G-CSFR) was founded in the human trophoblastic cell line that is implicated in regulation and proliferation of trophoblast. In the present study, the somatic cell NT...

Pigs are one of the most suitable alternative laboratory models than other animals, because they have similar cardiovascular, renal and gastrointestinal organs with those of human. However, in the case of genetically engineered animals, early development of embryos is inhibited by expression of foreign genes, there are many cases of miscarriage or...

Growth differentiation factor 8 (GDF8) is a member of the transforming growth factor-β family that has been identified as a strong physiological regulator. The purpose of this study is to investigate the effects of GDF8 on porcine oocytes during in vitro maturation (IVM). We investigated reactive oxygen species (ROS) levels, specific gene transcrip...