3D gonadal culture systems could expand fertility options in cats and dogs

A new Theriogenology review highlights a key bottleneck in canine and feline reproductive biotechnology: building 3D microenvironments that can mimic the gonadal niche closely enough to support germ cell development in vitro. In “3D microenvironments for gonadal cell development in domestic cats and dogs,” Martina Colombo, Valeria Vurchio, and Gaia Cecilia Luvoni examine how engineered culture systems might better support gonadal cells than conventional two-dimensional methods, with the goal of advancing in vitro gametogenesis for companion animals and conservation medicine. (air.unimi.it)

The idea is not new, but the timing matters. Cats and dogs have long lagged behind livestock and laboratory species in assisted reproductive technologies, in part because their reproductive physiology is unusually complex and species-specific. Earlier reviews have described domestic cats as a useful model for wild felids and dogs as an especially difficult species for in vitro embryo production and gamete maturation. Even so, fertility preservation has remained a priority because gonadal tissue can preserve a much larger pool of immature germ cells than mature gamete collection alone, which is particularly relevant for prepubertal animals, cancer patients, and rare or endangered bloodlines. (onlinelibrary.wiley.com)

According to the review summary available through the University of Milan repository, the authors describe a range of 3D approaches, including hydrogels, organoids, and biomimetic scaffolds produced through decellularization or 3D printing. These systems aim to provide not just structure, but also the biochemical and mechanical cues that gonadal cells need for survival, proliferation, and differentiation. The review notes that ovarian tissue and isolated follicles can be cultured either in situ or ex situ, and that male germline work in both species has generally supported maintenance or proliferation of spermatogonial populations, but not full maturation into functional sperm unless transplantation is added. (air.unimi.it)

That framing fits the broader literature. A Smithsonian National Zoo review on fertility preservation in domestic and wild carnivores reported encouraging progress in culturing cat and dog ovarian tissue and isolated follicles, especially in cats, while also noting that in vitro testicular culture in carnivores remains less developed. The same review described early work showing that more than half of germline and somatic cells in isolated cat and dog seminiferous tubules remained viable and continued differentiating in vitro for at least four weeks, a useful proof of concept but still far from routine gamete production. (pmc.ncbi.nlm.nih.gov)

More recent Theriogenology studies show the field is still building foundational pieces rather than delivering a near-term clinical tool. In 2026, researchers reported developmental expression patterns of spermatogonial stem cell markers in domestic cat testes, positioning that work as groundwork for SSC-based reproductive biotechnologies in felids. Other recent studies have focused on cat oocyte transport, culture media, and melatonin supplementation during in vitro maturation, again underscoring that optimization of the reproductive microenvironment is still an active and unresolved problem. (sciencedirect.com)

Expert and industry commentary around this area has been consistent for years: the promise is real, but translation is slow. Gaia Cecilia Luvoni previously wrote in WSAVA proceedings that cryostored oocytes or gonadal tissue could improve assisted reproduction by preserving genetic diversity and allowing embryo production when recipients and male gametes are available. Reviews in canine reproduction have also stressed that ovarian tissue preservation and later follicle growth remain technically difficult, especially in dogs, where efficient in vitro maturation and embryo production are still limited. (vin.com)

Why it matters: For veterinary professionals, this review is less about an immediate change in practice and more about where companion animal reproductive medicine may be headed. If 3D gonadal culture systems become more reliable, they could eventually support fertility preservation for young animals sterilized before puberty, patients facing gonadotoxic treatment, or breeding animals that die unexpectedly. They could also strengthen the role of domestic cats and dogs as translational models for threatened wild felids and canids, where every preserved genome can matter. But the current evidence suggests that veterinary teams should view this as platform science, not a ready clinical service. (pubmed.ncbi.nlm.nih.gov)

What to watch: The next inflection point will be studies that show reproducible generation of fertilization-competent oocytes or sperm from cat or dog gonadal tissue in defined 3D systems, ideally with standardized biomaterials, functional readouts, and post-thaw compatibility for biobanked samples. Until then, the practical value is in refining preservation pipelines and improving the quality of the cells and tissues that may one day feed these systems. (air.unimi.it)