Microalgae share key features with human erythrocytes and can safely circulate through the vascular system in mice.

As animal cells cannot produce oxygen, erythrocytes are responsible for gas interchange, being able to capture and deliver oxygen upon tissue request. Interestingly, several other cells in nature produce oxygen by photosynthesis, raising the question of whether they could circulate within the vascular networks, acting as an alternative source for oxygen delivery. To address this long-term goal, here some physical and mechanical features of the photosynthetic microalga Chlamydomona reinhardtii were studied and compared with erythrocytes, revealing that both exhibit similar size and rheological properties. Moreover, key biocompatibility aspects of the microalgae were evaluated in vitro and in vivo, showing that C. reinhardtii can be co-cultured with endothelial cells, without affecting each other's morphology and viability. Moreover, short-term systemic perfusion of the microalgae showed a thoroughly intravascular distribution in mice. Finally, the systemic injection of high numbers of microalgae did not trigger deleterious responses in living mice. Altogether, this work provides key scientific insights to support the notion that photosynthetic oxygenation could be achieved by circulating microalgae, representing another important step towards human photosynthesis. KEY POINTS: • C. reinhardtii and endothelial cells are biocompatible in vitro. • C. reinhardtii distribute throughout the entire vasculature after mice perfusion. • C. reinhardtii do not trigger deleterious responses after injection in mice.

Uso da ultrassonografia Doppler colorido na reprodução de pequenos ruminantes / Use of color Doppler ultrasonography in the reproduction of small ruminants

A ultrassonografia (US) Doppler colorido fornece uma ferramenta não invasiva valiosa para detectar e monitorar mudanças dinâmicas na rede vascular e fluxo sanguíneo em vários órgãos e tecidos reprodutivos. Em apoio as biotécnicas da reprodução animal assistida, a US Doppler colorido tem mostrada alta eficiência no monitoramento funcional das estruturas ovarianas. A previsão de respostas ovarianas e produções embrionária em ovinos pela identificação de sinais Doppler na parede folicular já se mostrou eficiente. A aplicação da US Doppler colorido para a identificação da funcionalidade do tecido luteal é ainda maior, desde acompanhamentos fisiológicos e diagnósticos de disfunções luteais até ampla aplicação em conjunto as diferentes biotécnicas reprodutivas. Destaca-se em ovelhas e cabras, a aplicação comercial da US Doppler colorido para o diagnóstico de gestação precoce, de disfunções luteais, de determinação de respostas ovarianas em fêmeas doadoras e receptoras de embriões, para identificar efeitos luteotrófico de estratégias hormonais, e ainda para amparar as estratégias de ressincronização de estro.(AU)

Color Doppler ultrasonography (US) provides a valuable non-invasive tool for detecting and monitoring dynamic changes in the vascular network and blood flow in various reproductive organs and tissues. In support of assisted animal reproduction biotechniques, color Doppler US has shown high efficiency in the functional monitoring of ovarian structures. The prediction of ovarian responses and embryonic production in sheep by identifying Doppler signals in the follicular wall has already proved to be efficient. The application of color Doppler US for identifying the functionality of the luteal tissue is even greater, from physiological monitoring and diagnosis of luteal dysfunctions to wide application together with different reproductive biotechniques. It stands out in sheep and goats, the commercial application of color Doppler US for the diagnosis of early pregnancy, luteal dysfunctions, determination of ovarian responses in embryo donor and recipient females, to identify luteotrophic effects of hormonal strategies, and even to support estrus resynchronization strategies.(AU)

The GPI-Anchored Protein Thy-1/CD90 Promotes Wound Healing upon Injury to the Skin by Enhancing Skin Perfusion.

Wound healing is a highly regulated multi-step process that involves a plethora of signals. Blood perfusion is crucial in wound healing and abnormalities in the formation of new blood vessels define the outcome of the wound healing process. Thy-1 has been implicated in angiogenesis and silencing of the Thy-1 gene retards the wound healing process. However, the role of Thy-1 in blood perfusion during wound closure remains unclear. We proposed that Thy-1 regulates vascular perfusion, affecting the healing rate in mouse skin. We analyzed the time of recovery, blood perfusion using Laser Speckle Contrast Imaging, and tissue morphology from images acquired with a Nanozoomer tissue scanner. The latter was assessed in a tissue sample taken with a biopsy punch on several days during the wound healing process. Results obtained with the Thy-1 knockout (Thy-1-/-) mice were compared with control mice. Thy-1-/- mice showed at day seven, a delayed re-epithelialization, increased micro- to macro-circulation ratio, and lower blood perfusion in the wound area. In addition, skin morphology displayed a flatter epidermis, fewer ridges, and almost no stratum granulosum or corneum, while the dermis was thicker, showing more fibroblasts and fewer lymphocytes. Our results suggest a critical role for Thy-1 in wound healing, particularly in vascular dynamics.

Follicular dynamics, luteal characteristics, and progesterone concentrations in synchronized lactating Holstein cows with high and low antral follicle counts.

We performed two experiments in high milk-producing Holstein cows. First, we evaluated the repeatability of the antral follicle count (AFC) - where all follicles were ≥2 mm in diameter - during the days of the ovulation synchronization protocol for timed artificial insemination (TAI) in dairy cows (n = 20). In the second study we investigated the follicular dynamics and Doppler ultrasonography in cows with low (≤15 follicles, n = 9) and high (≥25 follicles, n = 9) AFC, and measured progesterone (P4) concentrations during CL evaluation. In addition, the diameter of the preovulatory follicle, area of blood flow of the preovulatory follicle, CL area, and CL blood flow were compared between groups with high and low AFC. Ultrasound examinations were performed during the days of the protocol and 10 days after ovulation to assess the CL. The constancy of the AFC was analyzed by calculating the repeatability. Parametric variables were analyzed using the t-test, and nonparametric variables were analyzed using the Mann-Whitney test (P ≤ 0.05). The repeatability of the AFC on different days of the protocol was 0.98. Cows with low AFC showed a greater diameter of the preovulatory follicle (16 ± 0.3 vs. 15 ± 0.4 mm), blood flow area of the preovulatory follicle (17.3 ± 2.3 vs. 8.1 ± 3.2 mm2), CL area (579.1 ± 16.9 vs. 405.8 ± 21.2 mm2), area of CL perfusion (97.1 ± 9.4 vs. 68.3 ± 5.2 mm2), as well as higher P4 levels (3.1 ± 0.2 vs. 2.2 ± 0.2 ng/mL). In high milk-producing Holstein cows, the AFC has high repeatability on different days of the TAI protocol, and cows with a low AFC show larger preovulatory follicles and CLs with greater perfusion, in addition to greater P4 concentrations in comparison to those cows with a high AFC.

Ultrasonography-accessed luteal size endpoint that most closely associates with circulating progesterone during the estrous cycle and early pregnancy in beef cows.

The aim was to evaluate the associations between circulating P4 concentrations, corpus luteum (CL) size (diameter, area or volume) and blood perfusion (BP) in cows. In Experiment 1, Pearson's correlations (P < 0.05) with P4 concentrations were observed during CL development (D8) for total area (TA; r = 0.76), luteal area (ACL; r = 0.72), total and luteal diameter (TD and DCL respectively; r = 0.46). During mid-late diestrus, there was a positive correlation (P < 0.05) only at D15 with TA and ACL (r > 0.60), TD, total volume (TV) and luteal volume (VCL; r > 0.434). During luteal regression, the correlation was only observed at D18 for ACL (r = 0.478) and D20 with several variables. In Experiment 2, CL weight and ACL had the greatest correlation with P4 (r > 0.6). In Experiment 3, TA and ACL were the variables that were most closely correlated with serum P4 concentrations at D7 in recipient cows. Correlation coefficients were greater for luteal measurements when there were compact compared with cavitary CLs. In Experiment 4, there was no correlation (P > 0.05) between P4 and any of the variables measured on D4 and D7 in recipient cows detected in estrus. On D18 to D20, all CL characteristics were correlated (P < 0.05) with plasma P4, and luteal BP and BP area were more closely (P < 0.05) correlated than ACL. In conclusion, CL perimeter area measurements had the greatest association with luteal function during CL development; whereas for BP there was a greater correlation with P4 than luteal size during luteolysis.