Progress in the development and use of monoclonal antibodies to study the evolution and function of the immune systems in the extant lineages of ungulates

Details on the origin and function of the immune system are beginning to emerge from genomic studies tracing the origin of B and T cells and the major histocompatibility complex. This is being accomplished through identification of DNA sequences of ancestral genes present in the genomes of lineages of vertebrates that have evolved from a common primordial ancestor. Information on the evolution of the composition and function of the immune system is being obtained through development of monoclonal antibodies (mAbs) specific for the MHC class I and II molecules and differentially expressed on leukocytes differentiation molecules (LDM). The mAbs have provided the tools needed to compare the similarities and differences in the phenotype and function of immune systems that have evolved during speciation. The majority of information currently available on evolution of the composition and function of the immune system is derived from study of the immune systems in humans and mice. As described in the present review, further information is beginning to emerge from comparative studies of the immune systems in the extant lineages of species present in the two orders of ungulates, Perissodactyla and Artiodactyla. Methods have been developed to facilitate comparative research across species on pathogens affecting animal and human health.

Bovine models for human ovarian diseases

During early embryonic development, late fetal growth, puberty, adult reproductive years, and advanced aging, bovine and human ovaries closely share molecular pathways and hormonal signaling mechanisms. Other similarities between these species include the size of ovaries, length of gestation, ovarian follicular and luteal dynamics, and pathophysiology of ovarian diseases. As an economically important agriculture species, cattle are a foundational species in fertility research with decades of groundwork using physiologic, genetic, and therapeutic experimental techniques. Many technologies used in modern reproductive medicine, such as ovulation induction using hormonal therapy, were first used in cows before human trials. Human ovarian diseases with naturally occurring bovine correlates include premature ovary insufficiency (POI), polycystic ovarian syndrome (PCOS), and sex-cord stromal tumors (SCSTs). This article presents an overview of bovine ovary research related to causes of infertility, ovarian diseases, diagnostics, and therapeutics, emphasizing where the bovine model can offer advantages over other lab animals for translational applications.

An attempt to potentiate the ovarian superstimulatory response in cattle by co-treatment with an aromatase inhibitor

Letrozole is used for the treatment of subfertility in women undergoing ovarian superstimulation, but the mechanism of action has not been investigated critically. The objective was to test the hypothesis that treatment with letrozole will potentiate the superstimulatory response following gonadotropin treatment by increasing the number of follicles present at ovarian follicular wave emergence in cattle. In Experiment 1, ovarian follicular wave emergence was synchronized among beef heifers (n = 8) by transvaginal ultrasound-guided follicle ablation. On Day 0 (wave emergence), a letrozole-releasing device (LRD) was placed intravaginally for 5 days, followed again by transvaginal follicle ablation on Day 5. The number of follicles ≥3 mm was recorded by transrectal ultrasonography on Days 0 and 6.5 (i.e., pre- vs. post-LRD treatment). In Experiment 2, non-lactating dairy cows were assigned randomly to one of two groups (n = 15/gp) after follicle ablation-induced synchronization of wave emergence (Day 0), and given either an LRD or sham device for 5 days. Superstimulatory treatment was initiated on Day 0, consisting of 8 doses of 50 mg of porcine FSH im at 12 h intervals, and luteolytic doses of prostaglandin on Days 3 and 3.5. The LRD/sham devices were removed on Day 3.5, GnRH was given im on Day 5, estrus response was determined on Days 5 and 6, and the ovarian response was recorded by ultrasonography on Days 0, 3.5, 5, 6.5, and 12. In Experiment 1, no difference was detected in the number of antral follicles at wave emergence pre- vs. post-LRD treatment (23.2 ± 3.2 vs. 23.5 ± 3.8 follicles; P = 0.67; mean ± SEM). In Experiment 2, the interval from prostaglandin treatment to estrus was longer (50.3 ± 1.1 vs. 40.7 ± 2.0 h; P < 0.001) and less variable (residuals: 3.1 ± 0.5 vs. 6.7 ± 0.9 h; P < 0.01) in the LRD vs. sham group. The proportion of ovulations (number of CL on Day 12 over the number of follicles ≥3 mm on Day 0) did not differ (0.65 ± 0.02 vs. 0.70 ± 0.02; P = 0.15) nor did the number of CL on Day 12 (15.9 ± 2.5 vs. 19.0 ± 2.0; P = 0.32) between the LRD and sham groups. In summary, treatment with letrozole did not increase the number of antral follicles at wave emergence or the superstimulatory response, but increased precision in the interval to estrus and may be useful for artificial insemination at a fixed time in superstimulatory protocols.

Biomimetic surgical mesh to replace fascia with tunable force-displacement

Here we mimic the mechanical properties of native fascia to design surgical mesh for fascia replacement. Despite the widespread acceptance of synthetic materials as tissue scaffolds for pelvic floor disorders, mechanical property mismatch between mesh and adjacent native tissue drives fibrosis and erosion, leading the FDA to remove several surgical meshes from the market. However, autologous tissue does not induce either fibrosis or adjacent tissue erosion, suggesting the potential for biomimetic surgical mesh. In this study, we determined the design rules for mesh that mimics native fascia by mathematically modeling multi-component polymer networks, composed of elastin-like and collagen-like fibers, using a spring-network model. To validate the model, we measured the stress-strain curves of native bovine and nonhuman primate (Macaca mulatta) abdominal fascia in both toe and linear regions. We find that the stiffer collagen-like fibers must remain limp until the elastin-like fibers extend to the initial length of spanning collagen-like fibers under uniaxial tension. Comparing model results to experiment determines the product of fiber volume fraction and elastic modulus, a critical design parameter. Dual fiber mesh with mechanical properties that mimic fascia are feasible. These results have broad application to a wide range of soft tissue replacements including ~200,000 surgeries/year for pelvic floor disorders, because standard-of-care mesh contain only stiffer polymers that behave more like collagen than native tissue.

Calf Clinical Model of Cryptosporidiosis for Efficacy Evaluation of Therapeutics

Cryptosporidiosis, caused by the apicomplexan parasite Cryptosporidium parvum, is a moderate-to-severe diarrheal disease now recognized as one of the leading causes of morbidity and mortality in livestock globally, and in humans living in resource-limited parts of the world, particularly those with AIDS or malnourished individuals. This recognition has fueled efforts for the discovery of effective therapeutics. While recent progress in drug discovery has been encouraging, there are presently no acceptably effective parasite-specific drugs for the disease. The urgent need for new drug discovery or drug repurposing has also increased the need for refined animal models of clinical disease for therapeutic efficacy evaluation. Here, we describe an acute model of cryptosporidiosis using newborn calves to evaluate well-defined clinical and parasitological parameter outcomes, including the effect on diarrhea severity and duration, oocyst numbers produced, and multiple measures of clinical health. The model is highly reproducible and provides unequivocal direct measures of treatment efficacy on diarrhea severity and parasite replication.

Biomechanical Comparison Between Bashti Bone Plug Technique and Biodegradable Screw for Fixation of Grafts in Ligament surgery

BACKGROUND

Ligament reconstruction is a common procedure in orthopedic surgery. Although several popular techniques are currently in use, new methods are proposed for secure fixation of the tendon graft into the bone tunnel.

PURPOSES

We sought to introduce our new technique of Bashti bone plug for fixation of soft tissue graft in anterior cruciate ligament (ACL) reconstruction and to compare its biomechanical features with conventional absorbable interference screw technique in a bovine model.

METHODS

Twenty pairs of bovine knees were harvested after death. Soft tissue was removed and the Achilles tendon was harvested to be used as an ACL graft. It was secured into the bone tunnel on the tibial side via two different methods: Bashti Bone Plug technique and conventional screw method. Biomechanical strength was measured using 200 N and 300 N cyclic loading on the graft. Pull out strength was also tested until the graft fails.

RESULTS

No graft failure was observed after 200 N and 300 N cyclic loading in either fixation methods. When testing for pull out failure, 21 tendons (53%) were torn and 19 tendons (48%) slipped out. No fixation failure occurred, which did not reveal a significant difference between the bone plug or interference screw group (P=0.11). The mean pull out force until failure of the graft was 496±66 N in the screw group and 503±67 N in the bone plug group (P=0.76).

CONCLUSIONS

Our suggested fixation technique of Bashti bone plug is a native, cheap, and feasible method that provides comparable biomechanical strength with interference screw when soft tissue fixation was attempted in bovine model.