Ali Honaramooz

University of Saskatchewan | U of S · Department of Veterinary Biomedical Sciences

In vitro spermatogenesis (IVS) has important applications including fertility preservation of prepubertal cancer patients; however, thus far, IVS has only been achieved using mouse models. To study the effects of growth factors on the maintenance of testicular tissue integrity, germ cell numbers, and potential induction of IVS using a porcine model...

Long-term culture of testicular tissue has important applications, including the preservation of fertility potential of prepubertal boys undergoing gonadotoxic cancer treatment. This study was designed to define optimal conditions for the long-term culture of neonatal porcine testicular tissue as an animal model for preadolescent individuals. Teste...

Implantation of testis cell aggregates from various donors under the back skin of recipient mice results in de novo formation of testis tissue. We used this implantation model to study the putative in vivo effects of six different growth factors on testis cord development. Recipient mice (n = 7/group) were implanted with eight neonatal porcine test...

Gonocytes are germline stem cells in the neonatal testis with important potential applications in fertility restoration and transgenesis. Using stepwise experiments, we examined the effects of different media combined with fetal bovine serum (FBS) and/or knockout serum replacement (KSR) on the in vitro proliferation, colony-formation, ultrastructur...

Gonocytes in the neonatal testis have male germline stem cell properties and as such have important potential applications in fertility preservation and regenerative medicine. Such applications require further studies aimed at increasing gonocyte numbers and evaluating their pluripotency in vitro. The objective of the present study was to test the...

We have previously shown that implantation of testis cell aggregates under the back skin of immunodeficient mice results in de novo regeneration of testis tissue. We used this unique model to investigate the effects of epidermal growth factor (EGF) and glial cell-derived neurotrophic factor (GDNF) on testis cord development. Neonatal piglet testis...

Limb wounds are common in horses and often develop complications. Intravenous multipotent mesenchymal stromal cell (MSC) therapy is promising but has risks associated with intravenous administration and unknown potential to improve cutaneous wound healing. The objectives were to determine the clinical safety of administering large numbers of alloge...

The creation of a testis organoid (artificial testis tissue) with sufficient resemblance to the complex form and function of the innate testis remains challenging, especially using non-rodent donor cells. Here, we report the generation of an organoid culture system with striking biomimicry of the native immature testis tissue, including vasculature...

Introduction: Cell-based therapies with certain cell types are touted as novel and hopeful therapeutic intervention in the clinical setting. Here, we aimed to assess the regenerative potential of c-Kit⁺ cells in the rejuvenation of ovarian tissue and fertility rate in rat model of premature ovarian failure (POF). Methods: Rats were treated with 160...

Spermatogenic failure is believed to be a major cause of male infertility. The establishment of a testis organoid model would facilitate the study of such pathological mechanisms and open the possibility of male fertility preservation. Because of the complex structures and cellular events occurring within the testis, the establishment of a compartm...

The in vitro propagation and differentiation of spermatogonial stem cells (SSCs) has many potential applications within reproductive science and medicine. We established a two-dimensional (2D) cell culture system to proliferate and differentiate prepubertal mouse SSCs as a model capable of maximizing on a small number of donor SSCs. We also investi...

Testis tissue xenografting and testis cell aggregate implantation from various donor species into recipient mice are novel models for the study and manipulation of testis formation and function in target species. Thus far, the analysis of such studies has been limited to surgical or post-mortem retrieval of samples. Here we used ultrasound biomicro...

Gonocytes in the neonatal testis have male germline stem cell potential. The objective of the present study was to examine the behavior and ultrastructure of gonocytes in culture. Neonatal porcine testis cells were cultured for 4 weeks and underwent live-cell imaging to explore real-time interactions among cultured cells. This included imaging ever...

Limb wounds on horses are often slow to heal and are prone to developing exuberant granulation tissue (EGT) and close primarily through epithelialization, which results in a cosmetically inferior and non-durable repair. In contrast, wounds on the body heal rapidly and primarily through contraction and rarely develop EGT. Intravenous (IV) multipoten...

Spermatogonial stem cells (SSCs) are a rare group of cells in the testis that undergo self-renewal and complex sequences of differentiation to initiate and sustain spermatogenesis, to ensure the continuity of sperm production throughout adulthood. The difficulty of unequivocal identification of SSCs and complexity of replicating their differentiati...

Spermatogonial stem cells (SSCs) are the only adult stem cells capable of passing genes onto the next generation. SSCs also have the potential to provide important knowledge about stem cells in general and to offer critical in vitro and in vivo applications in assisted reproductive technologies. After century-long research, proof-of-principle cultu...

Ectopic implantation of donor testis cell aggregates in recipient mice results in de novo formation or regeneration of testis tissue and, as such, provides a unique invivo model for the study of testis development. However, currently the results are inconsistent and the efficiency of the model remains low. This study was designed to: (1) examine se...

Background: Subcutaneous grafting/implantation of neonatal testis tissue/cells from diverse donor species into recipient mice can be used as an in vivo model to study testis development, spermatogenesis, and steroidogenesis. Ultrasound biomicroscopy (UBM) allows obtaining high definition cross-sectional images of tissues at microscopic resolutions...

Introduction: Xenogeneic grafting of immature testis tissue from diverse donor species into recipient mice results in the development of grafted tissue, spermatogenesis, and production of functional sperm. More importantly, implantation of enzymatically dissociated neonatal pig or sheep testis cells in recipient mice results in de novo formation (r...

Introduction: Implantation of neonatal pig testis cells in host mice results in regeneration of a functional testis tissue; this model provides a powerful tool for the study of testis development and postnatal organogenesis. We utilized this implantation model to investigate the effects on seminiferous cord formation of several growth factors that...

Introduction: Ectopic implantation of neonatal pig testis cells under the back skin of recipient mice results in de novo formation (regeneration) of testis tissue; providing a unique model for deciphering the mechanism of testis development. The objective of the present study was to investigate the effects of EGF and GDNF on testis cords developmen...

Introduction: Xenogeneic grafting of neonatal testis tissue fragments and implantation of testis cell aggregates under the back skin of recipient mice can be used as unique in vivo models to study testis development, spermatogenesis, and steroidogenesis. The present study was designed to use ultrasound biomicroscopy (UBM) for non‐invasive monitorin...

Introduction: Given the teratogenic potential of embryonic stem cells and induced pluripotent stem (iPS) cells, alternative sources of pluripotent cells are desirable, especially in non-rodent animal models. Gonocytes are progenitors of spermatogonial stem cells in the neonatal testes. We have shown that once cultured, gonocytes can spontaneously d...

Background: Gonocytes give rise to spermatogonial stem cells, and thereby play an essential role in establishing spermatogenesis. Optimized culture conditions for gonocytes provide an opportunity for their study and in vitro manipulation for potential application in reproductive technologies. Using six experiments in a step-wise design, we examine...

Subcutaneous grafting of neonatal testis tissue fragments and implantation of testis cell aggregates from diverse donor species can lead to maturation of the testis cells/tissue and complete spermatogenesis in recipient mice. As such, this system can be used as an in vivo model to study testis development, spermatogenesis, and steroidogenesis of va...

Gonocytes in the neonatal testis are the precursors of all future types of germ cells; thereby, testis cell culture may provide a potential means for in vitro proliferation and manipulation of these male germline stem cells. We have recently developed an optimized system for short-term culture of neonatal porcine gonocytes. In the present study, we...

Horses often sustain cutaneous wounds and healing can be prolonged and difficult to treat. Compared to body wounds, limb wounds heal slower and are more likely to develop exuberant granulation tissue. Differences in healing rates and exuberant granulation tissue formation is attributed to abnormal cytokine profiles. CXCL8 and its receptor CXCR2 are...

Few sex-autosome chromosome abnormalities have been documented in domestic animal species. In humans, Y-autosome chromosome abnormalities may occur at a rate of 1/2,000 live births, whereas in the domestic pig only 2 Y-autosome reciprocal translocations have been previously described. During a routine cytogenetic screening of young boars, we identi...

Three-dimensional (3D)-printed constructs made of polycaprolactone (PCL) and chondrocyte-impregnated alginate hydrogel (hybrid cartilage constructs) mimic the biphasic nature of articular cartilage, offering promise for cartilage tissue engineering (CTE) applications. However, the regulatory pathway for medical device development requires validatio...

In tissue engineering, non-invasive imaging of biomaterial scaffolds and tissues in living systems is essential to longitudinal animal studies for assessments without interrupting the repair process. Conventional X-ray imaging is inadequate for use in soft tissue engineering due to the limited absorption difference between the soft tissue and bioma...

This article presents the data of using three phase-based X-ray imaging techniques to characterize biomaterial scaffold and soft tissues in situ, as reported in our study “Low-dose phase-based X-ray imaging techniques for in situ soft tissue engineering assessments” [1]. The examined parameters include the radiation dose, scan time, and image quali...

Elk velvet antler (EVA) has been used in traditional Oriental medicine for centuries to promote general health; however, little evidence for its effect on bone development is available. We investigated the effects of lifelong exposure of Wistar rats to a diet containing 10% EVA on physical growth and bone development. Measurements included weekly b...

Genetic modification of germline stem cells (GSCs) is an alternative approach to generate transgenic large animals where transgenic GSCs are transplanted into a recipient testis to generate donor-derived transgenic sperm. The objective of this study was to explore the application of viral vectors in delivering an EGFP transgene into GSCs for produc...

The purpose of this study was to evaluate the long-term outcome of testis tissue xenografting from immature deer. Testis tissue was collected post-mortem from a 2-mo-old white-tailed deer fawn (Odocoileus virginianus) and small fragments of the tissue were grafted under the back skin of immunodeficient recipient mice (n=7 mice; 8 fragments/mouse)....

Significant intrinsic fluorescence in tissues and in disassociated cells can interfere with fluorescence identification of target cells. The objectives of the present study were (1) to examine an intrinsic fluorescence we observed in both the piglet testis tissue and cells and (2) to test an effective method to block the autofluorescence. We observ...

Elk velvet antler (EVA) has a traditional use for promotion of general health. However, evidence of EVA effects at different lifestages is generally lacking. This paper investigated the effects of long-term maternal dietary EVA supplementation on physical, reflexological and neurological development of rat offspring. Female Wistar rats were fed sta...

Preparation of the recipient testes can enhance the outcome of germ cell transplantation. Whether neonatal pig gonocytes have stem cell potential has not been shown. Therefore, the objectives of the present study were 1) to examine the effects of neonatal piglet testis irradiation on testis development and subsequent endogenous spermatogenesis, and...

Gonocytes can be identified in situ and in histological cross-sections by their unique morphological attributes and distinctive topography within the seminiferous cords/tubules; however, specific biomarkers are required for their accurate quantification. In search for such a specific biomarker for piglet gonocytes, we encountered an intense auto-fl...

The purpose of this study was to evaluate the long-term outcome of testis tissue xenografting from bison and deer as models for closely-related rare or endangered ungulates. Testis tissue was collected post-mortem from 2 newborn bison calves (Bison bison bison) and a 2-mo-old white-tailed deer fawn (Odocoileus virginianus). Small fragments of donor...

The objective was to evaluate the long-term outcome of testis tissue xenografting from neonatal bison calves as a model for closely related rare or endangered ungulates. Testis tissue was collected postmortem from two newborn bison calves (Bison bison bison) and small fragments of the tissue were grafted under the back skin of immunodeficient recip...

Gonocytes are the only type of germ cells present in the postnatal testis and give rise to spermatogonial stem cells. Purification of gonocytes has important implications for the study and manipulation of these cells and may provide insights for the ongoing investigation of the male germline stem cells. To obtain a pure population of gonocytes from...

Lymphoid-specific helicase (HELLS; also known as LSH) is a member of the SNF2 family of chromatin remodeling proteins. Because Hells-null mice die at birth, a phenotype in male meiosis cannot be studied in these animals. Allografting of testis tissue from Hells(-/-) to wild-type mice was employed to study postnatal germ cell differentiation. Testes...

To optimize the procedure for testis tissue xenografting, we grafted 2, 4, 8, or 16 small fragments of immature porcine testis tissue under the back skin of immunodeficient castrated mice (n = 10 mice/group). At 8 months post grafting, the graft recovery rate did not differ between groups; however, not only the total but also the average graft weig...

Transplantation of isolated germ cells from a fertile donor male into the seminiferous tubules of infertile recipients can result in donor-derived sperm production. Therefore, this system represents a major development in the study of spermatogenesis and a unique functional assay to determine the developmental potential and relative abundance of sp...

The aim of the present study was to examine factors that may affect the outcome of testis tissue xenografting. Recipient factors were examined by grafting small fragments of testis tissue from newborn piglets under the back skin of immunodeficient mice of different strains (severe combined immunodeficiency (SCID) v. nude), sex (male v. female) and...

The objective of this study was to develop effective strategies for hypothermic preservation of immature porcine testis tissue to maintain structural integrity and cell viability. In Experiment 1, testes from 1-week-old piglets were used to study the effects of tissue sample size (as intact testes or fragments of 100-or 30 mg) and the use of one of...

Grafting of donor mammalian testis tissue into recipient mice allows completion of spermatogenesis in the grafted tissue and therefore can serve as a new option for preservation of male germ line. For testis tissue xenografting, castrated male nude mice typically serve as recipients, each receiving 8 testis tissue fragments; however, no study has c...

The effects of medium and hypothermic temperatures on testis cells were investigated to develop a strategy for their short-term preservation. Testes from 1-week-old piglets were enzymatically dissociated for cell isolation. In Experiment 1, testis cells were stored at either room (RT) or refrigeration (RG) temperature for 6 days in one of 13 differ...

Spermatogenesis from many mammalian species occurs in fragments of normal testis tissue xenografted to mice. Here we apply xenografting to the study of testicular pathology. Using the horse model, we investigated whether exposure to a permissive extratesticular environment in the mouse host would rescue spermatogenesis in cryptorchid testicular tis...

Gonocytes have germline stem cell potential and are present in the neonatal testis, comprising 5-10% of freshly isolated testis cells. Maximising the number and proportion of gonocytes among freshly isolated testis cells will greatly facilitate their subsequent purification and in vitro study and manipulation. Seven experiments were conducted to ev...

The objective of this study was to examine the effect of donor age on progression of spermatogenesis in dog (Canis lupus familiaris) testis tissue after xenografting. In Experiment 1, canine testes were obtained by surgical castration. Based on developmental pattern of spermatogenesis at the time of grafting, donors were categorized as immature, yo...

The purpose of this study was to develop effective strategies for cooling and cryopreservation of immature porcine testis tissue that maintain its developmental potential. Testes from 1-wk-old piglets (Sus domestica) were subjected to 1 of 12 cooling/cryopreservation protocols: as intact testes, cooling at 4 degrees C for 24, 48, or 72h (Experiment...

Gonocytes are the first identifiable germ cells in the testis and progenitors of spermatogonial stem cells. The objective of this study was to maximize gonocyte isolation yield to facilitate the in vitro study and manipulation of these male germline stem cells. Fresh testis tissues from 3-day-old piglets were subjected to mechanical dissociation (P...

Grafting of immature mammalian testis tissue to mouse hosts can preserve the male germline. To make this approach applicable to a clinical or field situation, it is imperative that the testis tissue and/or spermatozoa harvested from grafted tissue are preserved successfully. The aim of the present study was to evaluate protocols for the preservatio...

Recovery of germ cells could be an option for preservation of the genetic pool of endangered animals. In immature males, xenografting of testis tissue provides the opportunity to recover sperm from these animals. In adult animals, xenografting has been less successful, but de novo morphogenesis of functional testis tissue from dissociated testis ce...

Xenografting of testis tissue from immature males from several mammalian species to immunodeficient mouse hosts results in production of fertilization-competent sperm. However, the efficiency of testis tissue xenografting from adult donors has not been critically evaluated. Testis tissue xenografting from sexually mature animals could provide an op...

Biology of Reproduction (2208) 78:312.118a

Recovery of germ cells is an important tool to preserve the genetic resources of endangered animals. In adult males, sperm cannot always be collected and cryopreserved and testis tissue xenografting has shown little success. Formation of functional testis tissue after xenografting of dissociated testis cells has been reported for pigs and rodents a...

The study and manipulation of testis cells require their preservation for various length of time. There are situations where it is necessary to maintain cells in suspension for up to several days (e.g., shipment of cells between collaborating labs). In such cases, culturing the cells at 37°C may not be suitable and resorting to cryopreservation wil...

We explored whether exposure of mammalian germ line stem cells to adeno-associated virus (AAV), a gene therapy vector, would lead to stable transduction and transgene transmission. Mouse germ cells harvested from experimentally induced cryptorchid donor testes were exposed in vitro to AAV vectors carrying a GFP transgene and transplanted to germ ce...

Embryo development after homologous intracytoplasmic sperm injection (ICSI) with sperm from testis tissue xenografts from pigs or any other farm animal species has not been evaluated critically. Here, we report development of porcine embryos in vitro following ICSI with sperm retrieved from xenografted neonatal pig testis. Small pieces of testis ti...

Testicular cell isolation is a starting step for culture, enrichment, modification or transplantation of spermatogonial stem cells. Therefore, the efficiency of enzymatic dissociation of the testis tissue is a potential limiting factor for such stem cell applications. Protocols used for testis cell isolation vary depending on the species from which...

Lymphoid specific helicase (Lsh) is a member of the SNF2-helicase family of chromatin remodeling proteins. Lsh is ubiquitously expressed and essential in embryonic development. We demonstrated recently that Lsh plays a critical role in female meiosis. Because Lsh null mice die at birth, a potential phenotype in male meiosis cannot be studied in the...

During mammalian development, morphogenesis of the testis requires the coordinated interplay of somatic cells to form seminiferous cords in which the primitive germ cells reside. These cords are the precursor of the functional male gonad and as such form the basis of male fertility. Cell migration during mammalian organogenesis and formation of com...

Testis tissue grafting presents an option for preservation of genetic material when sperm recovery is not possible. Grafting of testis tissue from sexually immature males to immunodeficient mice results in germ cell differentiation and production of fertilization competent sperm from different mammalian species (Honaramooz A et al. 2002 Nature 418,...

The objectives of this study were to determine if the response to luteinizing hormone releasing hormone (LHRH) could be used to select bull calves capable of early sexual maturation and to establish the optimum route and dose of LHRH. In Trial 1, at 4, 10 and 20 week of age, 20 calves were treated iv with 2 microg/kg body weight of LHRH 1 and 5h af...

Grafting of testis tissue from immature animals to immunodeficient mice results in complete spermatogenesis, albeit with varying efficiency in different species. The objectives of this study were to investigate if grafting of horse testis tissue would result in spermatogenesis, and to assess the effect of exogenous gonadotropins on xenograft develo...

Grafting of testicular tissue into immunodeficient mice has become an interesting and promising scientific tool for the generation of gametes and the study of testicular function. This technique might potentially be used to generate sperm from patients whose testes need to be removed or are destroyed due to therapeutic intervention or as a conseque...

Spermatogenesis can occur in testis tissue from immature bulls ectopically grafted into mouse hosts; however, efficiency of sperm production is lower than in other donor species. To elucidate a possible mechanism for the impaired spermatogenesis in bovine testis xenografts, germ cell fate and xenograft development were investigated at different tim...