Spermatogonial stem cell technologies: applications from human medicine to wildlife conservation.

Spermatogonial stem cell (SSC) technologies that are currently under clinical development to reverse human infertility hold the potential to be adapted and applied for the conservation of endangered and vulnerable wildlife species. The biobanking of testis tissue containing SSCs from wildlife species, aligned with that occurring in pediatric human patients, could facilitate strategies to improve the genetic diversity and fitness of endangered populations. Approaches to utilize these SSCs could include spermatogonial transplantation or testis tissue grafting into a donor animal of the same or a closely related species, or in vitro spermatogenesis paired with assisted reproduction approaches. The primary roadblock to progress in this field is a lack of fundamental knowledge of SSC biology in non-model species. Herein, we review the current understanding of molecular mechanisms controlling SSC function in laboratory rodents and humans, and given our particular interest in the conservation of Australian marsupials, use a subset of these species as a case-study to demonstrate gaps-in-knowledge that are common to wildlife. Additionally, we review progress in the development and application of SSC technologies in fertility clinics and consider the translation potential of these techniques for species conservation pipelines.

Adenosine A2A receptor regulation of microglia morphological remodeling-gender bias in physiology and in a model of chronic anxiety.

Developmental risk factors, such as the exposure to stress or high levels of glucocorticoids (GCs), may contribute to the pathogenesis of anxiety disorders. The immunomodulatory role of GCs and the immunological fingerprint found in animals prenatally exposed to GCs point towards an interplay between the immune and the nervous systems in the etiology of these disorders. Microglia are immune cells of the brain, responsive to GCs and morphologically altered in stress-related disorders. These cells are regulated by adenosine A2A receptors, which are also involved in the pathophysiology of anxiety. We now compare animal behavior and microglia morphology in males and females prenatally exposed to the GC dexamethasone. We report that prenatal exposure to dexamethasone is associated with a gender-specific remodeling of microglial cell processes in the prefrontal cortex: males show a hyper-ramification and increased length whereas females exhibit a decrease in the number and in the length of microglia processes. Microglial cells re-organization responded in a gender-specific manner to the chronic treatment with a selective adenosine A2A receptor antagonist, which was able to ameliorate microglial processes alterations and anxiety behavior in males, but not in females.

PLGA Implants containing vancomycin and dexamethasone: development, characterization and bactericidal effects.

Post-operative endophthalmitis is an infection and an inflammation of the eye following a surgical procedure. Its treatment is based on drug injections into the eye. However, this treatment can lead to ocular complications. Intraocular implants could substitute the conventional therapy. Poly(lactic-co-glycolic acid) (PLGA) implants comprising on vancomycin and dexamethasone were evaluated as drug delivery system to treat endophthalmitis after cataract surgery. Implants were characterized by drug content uniformity, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Wide Angle X-ray Scattering (WAXS), Scanning Electron Microscopy (SEM) and in vitro drug release. The bactericidal effect of vancomycin, eluted from the implants, was demonstrated against Staphylococcus aureus and Staphylococcus epidermidis. The drugs were uniformly distributed in the polymer. The analytical techniques revealed the chemical integrity of the drugs incorporated into the polymer and the modification of dexamethasone semi-crystalline nature. Drugs were controlled released from implants; and the eluted vancomycin showed bactericidal effects. In conclusion, PLGA implants containing vancomycin and dexamethasone may represent a therapeutic alternative to treat post-operative endophthalmitis.