Jennifer Nagashima is a Conservation Biologist with NZCBI's Center for Species Survival. Nagashima’s research focuses on developing new “gamete rescue” technologies in canids and felids. These technologies include freezing sperm and culturing ovaries in vitro to grow mature eggs. As part of her doctoral dissertation in the joint graduate training program between Cornell University and NZCBI, Nagashima produced the world’s first litter of puppies from in vitro fertilization. Nagashima earned her bachelor’s degree from Cornell University in animal science in 2009, and her doctorate in Zoology and Wildlife Conservation in 2015.

Developing assisted reproductive technologies is often extremely challenging for wildlife species where little to nothing may be known about their physiology or basic reproductive biology. However, tools such as genome rescue (salvaging sperm/eggs or ovarian/testicular tissue from animals that have passed away before breeding), sperm/egg/embryo cryopreservation, and artificial insemination can be extremely powerful means to manage the genetic diversity of endangered populations.

Dr. Jennifer Nagashima and her colleagues at the Smithsonian National Zoo and Conservation Biology Institute are working on advancing several cutting-edge laboratory techniques toward this goal. In collaboration with biomedical engineers from Stanford University and the University of Maryland, they have developed a prototype ‘ovary-on-a-chip’, a micro-fluidic device for ovarian tissue which allows for the mimicry of cell culture media flow through the incubated sample, similar to the flow of blood through the organ. Ultimately, they aim to be able to consistently grow mature, fertilizable eggs from ovarian tissue, allowing for the ‘rescue’ of the genetic potential of valuable female animals even post-mortem.

On the male side, they are studying the beneficial effects of supplementing vesicles produced from the female reproductive tract on sperm motility and viability following cryopreservation-thawing. Though understanding the communications between the female reproductive tract and the sperm and eggs, they hope to develop improved cryopreservation protocols that will allow for the best post-thaw recovery and developmental potential of banked gametes.  

Article

• Stewart, Samantha, White, Alisa, Ou, Wenquan, Liu, Wei, Nagashima, Jennifer, Songsasen, Nucharin, and He, Xiaoming. 2024. "Controlled Ice Nucleation with a Sand-PDMS Film Device Enhances Cryopreservation of Mouse Preantral Ovarian Follicles." Journal of Medical Devices, 1–27. https://doi.org/10.1115/1.4066445. 2024
• Nagashima, Jennifer B., Zenilman, Shoshana, Raab, April, Aranda-Espinoza, Helim, and Songsasen, Nucharin. 2023. "Comparative Tensile Properties and Collagen Patterns in Domestic Cat (Felis catus) and Dog (Canis lupus familiaris) Ovarian Cortical Tissues." Bioengineering, 10, (11). https://doi.org/10.3390/bioengineering10111285. 2023
• Hartzler, Kate E., McCartney, Chiara, Songsasen, Nucharin, and Nagashima, Jennifer B. 2023. "Cryopreservation of African painted dog (Lycaon pictus) ovarian tissue." Frontiers in Veterinary Science, 10. https://doi.org/10.3389/fvets.2023.1134726. 2023
• Dahal, R., Nagashima, Jennifer B., Songsasen, Nucharin, and Wood, T. 2022. "150 The influence of follicular fluid extracellular vesicles on in vitro maturation of oocytes in the domestic cat." Reproduction, Fertility and Development, 34, (2) 313. https://doi.org/10.1071/RDv34n2Ab150. 2022
• Nagashima, Jennifer B. and Songsasen, Nucharin. 2022. "60 Follicular fluid extracellular vesicles: endocytosis and influence on domestic cat cumulus cells and oocytes." Reproduction, Fertility and Development, 34, (2) 266. https://doi.org/10.1071/RDv34n2Ab60. 2022
• Rowlison, Tricia, Nagashima, Jennifer, Acker, Jason Paul, Ben, Robert, Daly, Jonathan, Hagedorn, Mary, and Comizzoli, Pierre. 2022. "First Report of Successful Laser Warming for Frozen Gonadal Tissues and Oocytes in the Domestic Cat Model." Biopreservation and Biobanking, https://doi.org/10.1089/bio.2022.0071. 2022
• Nagashima, Jennifer B. and Songsasen, Nucharin. 2021. "Canid Reproductive Biology: Norm and Unique Aspects in Strategies and Mechanisms." Animals, 11, (3). https://doi.org/10.3390/ani11030653. 2021
• Andrae, Christopher S., Oliveira, Erika C. S., Ferraz, Marcia A. M. M., and Nagashima, Jennifer B. 2021. "Cryopreservation of grey wolf (Canis lupus) testicular tissue." Cryobiology 100:173-179. https://doi.org/10.1016/j.cryobiol.2021.01.010 2021
• Nagashima, Jennifer B., Hill, Andrea M., and Songsasen, Nucharin. 2021. "In vitro development of mechanically and enzymatically isolated cat ovarian follicles." Reproduction and Fertility, 2, (1) 35–46. https://doi.org/10.1530/RAF-20-0067. 2021
• de Almeida Monteiro Melo Ferraz, Marcia, Nagashima, Jennifer Beth, Venzac, Bastien, Le Gac, Séverine, and Songsasen, Nucharin. 2020. "3D printed mold leachates in PDMS microfluidic devices." Scientific Reports, 10, (1) Article 994. https://doi.org/10.1038/s41598-020-57816-y. 2020
• de Almeida Monteiro Melo Ferraz, Marcia, Nagashima, Jennifer Beth, Venzac, Bastien, Le Gac, Séverine, and Songsasen, Nucharin. 2020. "A dog oviduct-on-a-chip model of serous tubal intraepithelial carcinoma." Scientific Reports, 10, (1) 1–11. https://doi.org/10.1038/s41598-020-58507-4. 2020
• de Almeida Monteiro Melo Ferraz, Marcia, Fujihara, Mayako, Nagashima, Jennifer Beth, Noonan, Michael James, Inoue-Murayama, Miho, and Songsasen, Nucharin. 2020. "Follicular extracellular vesicles enhance meiotic resumption of domestic cat vitrified oocytes." Scientific Reports, 10, (1). https://doi.org/10.1038/s41598-020-65497-w. 2020
• Nagashima, Jennifer B., Ferraz,Marcia de Almeida Monteiro Melo, Kamen, Sarah H., and Songsasen, Nucharin. 2020. "Investigating media that support red wolf (Canis rufus) sperm viability and capacitation in vitro." Reproduction and Fertility, 1, (1) 83–92. https://doi.org/10.1530/RAF-20-0042. 2020
• Ferraz,Marcia de Almeida Monteiro Melo, Nagashima, Jennifer Beth, Noonan, Michael James, Crosier, Adrienne E., and Songsasen, Nucharin. 2020. "Oviductal Extracellular Vesicles Improve Post-Thaw Sperm Function in Red Wolves and Cheetahs." International Journal of Molecular Sciences, 21, (10). https://doi.org/10.3390/ijms21103733. 2020
• Nagashima, Jennifer B., Wildt, David E., Travis, Alexander J., and Songsasen, Nucharin. 2019. "Activin promotes growth and antral cavity expansion in the dog ovarian follicle." Theriogenology, 129 168–177. https://doi.org/10.1016/j.theriogenology.2019.02.018. 2019
• Thongkittidilok, Chommanart, Doriguzzi, Nicole, Nagashima, Jennifer, Brown, Megan, Chansaenroj, Ajjima, and Songsasen, Nucharin. 2019. "Cilostamide and forskolin maintain gap junction function of incubated dog follicles." Theriogenology, 142 222–228. https://doi.org/10.1016/j.theriogenology.2019.09.034. 2019
• Nagashima, Jennifer B., El Assal, R., Songsasen, Nucharin, and Demirci, U. 2018. "Evaluation of an ovary-on-a-chip in large mammalian models: Species specificity and influence of follicle isolation status." Journal of Tissue Engineering and Regenerative Medicine, 12, (4) e1926–e1935. https://doi.org/10.1002/term.2623. 2018
• Place, Ned J., Crosier, Adrienne E., Comizzoli, Pierre, Nagashima, Jennifer B., Haefele, Holly, Schmidt-Küntzel, Anne, and Marker, Laurie L. 2017. "Age-associated and deslorelin-induced declines in serum anti-Müllerian hormone concentrations in female cheetahs, Acinonyx jubatus." General and comparative endocrinology, 250 54–57. https://doi.org/10.1016/j.ygcen.2017.06.003. 2017
• Songsasen, Nucharin, Nagashima, Jennifer B., and Thongkittidilok, C. 2017. "Endocrine and paracrine controls of canine follicular development and function." Reproduction in Domestic Animals, 52, (Supplement S2) 29–34. https://doi.org/10.1111/rda.12858. 2017
• Nagashima, Jennifer B., Hansen, B. S., Songsasen, Nucharin, Travis, A. J., and Place, N. J. 2016. "Anti-Müllerian Hormone in the Domestic Dog during the Anestrus to Oestrous Transition." Reproduction in Domestic Animals, 51, (1) 158–164. https://doi.org/10.1111/rda.12660. 2016
• Nagashima, Jennifer B., Wildt, David E., Travis, Alexander J., and Songsasen, Nucharin. 2015. "Follicular size and stage and gonadotropin concentration affect alginate-encapsulated in vitro growth and survival of pre- and early antral dog follicles." Reproduction, Fertility and Development, 29, (2) 262–273. https://doi.org/10.1071/RD15004. 2015
• Nagashima, Jennifer B., Sylvester, Skylar R., Nelson, Jacquelyn L., Cheong, Soon Hon, Mukai, Chinatsu, Lambo, Colleen, Flanders, James A., Meyers-Wallen, Vicki, Songsasen, Nucharin, and Travis, Alexander J. 2015. "Live Births from Domestic Dog (Canis familiaris) Embryos Produced by In Vitro Fertilization." PloS One, 10, (12). https://doi.org/10.1371/journal.pone.0143930. 2015
• Pukazhenthi, Budhan S., Nagashima, Jennifer B., Travis, Alexander J., Costa, Guilherme M., Escobar, Enrique N., França, Luiz R., and Wildt, David E. 2015. "Slow freezing, but not vitrification supports complete spermatogenesis in cryopreserved, neonatal sheep testicular xenografts." PloS One, 10, (4). https://doi.org/10.1371/journal.pone.0123957. 2015
• Harkey, Michael A., Asano, Atsushi, Zoulas, Mary Ellen, Torok-Storb, Beverly, Nagashima, Jennifer B., and Travis, Alexander. 2013. "Isolation, genetic manipulation, and transplantation of canine spermatogonial stem cells: progress toward transgenesis through the male germ-line." Reproduction 146 (1):75-90. https://doi.org/10.1530/REP-13-0086 2013
• Kiso, Wendy K., Selvaraj, Vimal, Nagashima, Jennifer B., Asano, Atsushi, Brown, Janine L., Schmitt, Dennis L., Leszyk, John, Travis, Alexander J., and Pukazhenthi, Budhan S. 2013. "Lactotransferrin in Asian Elephant (Elephas maximus) Seminal Plasma Correlates with Semen Quality." PLoS ONE, 8, (8) e71033. https://doi.org/10.1371/journal.pone.0071033. 2013
• Songsasen, Nucharin, Comizzoli, Pierre, Nagashima, Jennifer B., Fujihara, Mayako, and Wildt, David E. 2012. "The Domestic Dog and Cat as Models for Understanding the Regulation of Ovarian Follicle Development In Vitro." Reproduction in Domestic Animals, 47, (Supplement S6) 13–18. https://doi.org/10.1111/rda.12067. 2012

Chapter

• Nagashima, J. B., Travis, A. J., and Songsasen, Nucharin. 2019. "The Domestic Dog Embryo: In Vitro Fertilization, Culture, and Transfer." In Comparative Embryo Culture: Methods and Protocols. Herrick, Jason R., editor. 247–267. New York: Springer. In Methods in Molecular Biology. 2019

Review

• Songsasen, Nucharin and Nagashima, Jennifer. 2020. [Book review] "Intraovarian regulation of folliculogenesis in the dog: A review." Reproduction in Domestic Animals, 55, (S2), 66–73. https://doi.org/10.1111/rda.13657. 2020

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