Rho-associated coiled-coil containing kinase inhibitor improves outcomes of direct-transfer slow-cooled bovine blastocysts.

Direct-transfer slow-cooling cryopreservation is a widely used method for bovine embryo cryopreservation. However, the transfer of cryopreserved embryos is associated with reduced pregnancy rates. Rho-associated coiled-coil containing kinase inhibitor (ROCKi) has shown promise in improving the viability of post-warmed vitrified bovine embryos. Our objective was to investigate the effects of ROCKi treatment prior to slow-cooling or after cryopreservation on embryo viability. In vitro produced bovine embryos (n = 571) were randomly assigned to one of five groups: No-cryopreservation control group (NC-C), C-C group were cryopreserved by slow-rate cooling without ROCKi at any point, R-C group were incubated with ROCKi for 2 h before cryopreservation, C-R group were not exposed to ROCKi prior to cryopreservation but were cultured with ROCKi after cryopreservation, and R-R group were exposed to ROCKi before and after cryopreservation. Treatment group was significantly associated with blastocoel re-expansion, hatching, and degeneration (P < 0.0001). Blastocoel re-expansion rates were lower (P < 0.05) in the C-C (75.2 ± 4.2%) and R-C (85.2 ± 4.7%) groups compared with the NC-C (99.0 ± 0.7%), C-R (94.7 ± 2.6%) and the R-R (94.5 ± 2.9%) groups. The median time to re-expansion was significantly slowest in the C-C group (650, 560-915 min), followed by the R-C group (538, 421-611 min), then the C-R and R-R groups were similar (291, 261-361 and 321, 271-371 min) and the NC-C group was the fastest (196, 161-230 min) (P < 0.05). Similarly, the post-thaw hatching rate was lower, and the median time to hatching slower in the C-C (58.1 ± 7.0%, 2,033, 1634-2820 min) and R-C (65.7 ± 6.9%, 1,853, 1494-2356 min) groups compared with the NC-C (81.7 ± 6.0%, 1,309, 1084-1514 min), C-R (77.2 ± 6.5%, 1,384, 1013-1754 min) and R-R (82.0 ± 5.3%, 1,209, 943-1424 min) groups. ROCKi supplementation after cryopreservation resulted in fewer degenerated embryos (C-R = 8.9 ± 2.8%, and R-R 7.1 ± 2.8%) compared to the C-C (26.8 ± 4.3%) and R-C (17.9 ± 5.7%) groups. Exposure to ROCKi both before cryopreservation and after-cryopreservation yielded the best outcomes, similar to NC-C control group without cryopreservation, and significantly better than the C-C control group without supplements. Exposure to ROCKi after cryopreservation demonstrated greater benefits compared to exposure before cryopreservation alone. These findings suggest that ROCKi can potentially enhance cryosurvival of bovine embryos.

A Combined Region- and Pixel-Based Deep Learning Approach for Quantifying Abdominal Adipose Tissue in Adolescents Using Dixon Magnetic Resonance Imaging.

BACKGROUND: The development of adipose tissue during adolescence may provide valuable insights into obesity-associated diseases. We propose an automated convolutional neural network (CNN) approach using Dixon-based magnetic resonance imaging (MRI) to quantity abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) in children and adolescents. METHODS: 474 abdominal Dixon MRI scans of 136 young healthy volunteers (aged 8-18) were included in this study. For each scan, an axial fat-only Dixon image located at the L2-L3 disc space and another image at the L4-L5 disc space were selected for quantification. For each image, an outer and an inner region around the abdomen wall, as well as SAT and VAT pixel masks, were generated by expert readers as reference standards. A standard U-Net CNN architecture was then used to train two models: one for region segmentation and one for fat pixel classification. The performance was evaluated using the dice similarity coefficient (DSC) with fivefold cross-validation, and by Pearson correlation and the Student's t-test against the reference standards. RESULTS: For the DSC results, means and standard deviations of the outer region, inner region, SAT, and VAT comparisons were 0.974 ± 0.026, 0.997 ± 0.003, 0.981 ± 0.025, and 0.932 ± 0.047, respectively. Pearson coefficients were 1.000 for both outer and inner regions, and 1.000 and 0.982 for SAT and VAT comparisons, respectively (all p = NS). CONCLUSION: These results show that our method not only provides excellent agreement with the reference SAT and VAT measurements, but also accurate abdominal wall region segmentation. The proposed combined region- and pixel-based CNN approach provides automated abdominal wall segmentation as well as SAT and VAT quantification with Dixon MRI and enables objective longitudinal assessment of adipose tissues in children during adolescence.