Early stress exposure on zebrafish development: effects on survival, malformations and molecular alterations.

The effects of stress during early vertebrate development can be especially harmful. Avoiding stressors in fish larvae is essential to ensure the health of adult fish and their reproductive performance and overall production. We examined the consequences of direct exposure to successive acute stressors during early development, including their effects on miR-29a and its targets, survival, hatching and malformation rates, larval behaviour and cartilage and eye development. Our aim was to shed light on the pleiotropic effects of early-induced stress in this vertebrate model species. Our results showed that direct exposure to successive acute stressors during early development significantly upregulated miR-29a and downregulated essential collagen transcripts col2a1a, col6a2 and col11a1a, decreased survival and increased malformation rates (swim bladder, otoliths, cardiac oedema and ocular malformations), promoting higher rates of immobility in larvae. Our results revealed that stress in early stages can induce different eye tissular architecture and cranioencephalic cartilage development alterations. Our research contributes to the understanding of the impact of stressful conditions during the early stages of zebrafish development, serving as a valuable model for vertebrate research. This holds paramount significance in the fields of developmental biology and aquaculture and also highlights miR-29a as a potential molecular marker for assessing novel larval rearing programmes in teleost species.

Polyphenols and IUGR Pregnancies: Effects of Maternal Hydroxytyrosol Supplementation on Postnatal Growth, Metabolism and Body Composition of the Offspring.

Maternal supplementation with the polyphenol hydroxytyrosol in a swine model of intrauterine growth restriction (IUGR) improves the fetal oxidative status, decreases the appearance of low birth-weight neonates and favors growth during early postnatal stages (lactation). The current study aimed to determine whether hydroxytyrosol supplementation can also improve developmental patterns, metabolic traits, and body composition of the offspring during later postnatal stages (from weaning to adulthood). A total of 21 piglets born from control untreated sows and 20 piglets born from sows treated with hydroxytyrosol during the last two-thirds of pregnancy were selected on the basis of similar body weights at weaning, for avoiding any interfering effects occurred during lactation. The pigs in the treated group had higher average daily weight gain (ADWG) and, therefore, reached higher body weight and corpulence, greater muscle development and higher adiposity than their control counterparts. The following were not found: significant effects on metabolism and body composition except changes in the muscular fatty acid composition of the treated pigs coming from the largest litters; those more affected by IUGR processes. These findings suggest that maternal supplementation with hydroxytyrosol may improve juvenile development of offspring in at-risk pregnancies and pave the way for more specific studies aiming to elucidate effects on adiposity, metabolism, and meat organoleptic characteristics.

Preclinical evaluation of coronary stents: focus on safety issues.

In recent years, we have witnessed a revolution in the treatment of coronary artery disease. The development and improvement of drug eluting stents (DES) have lowered the incidence of restenosis to one-digit figures. In the search for a superior efficacy, animal models have played a key role. The classical swine model of coronary stenting remains the preferred model to measure restenosis, although the rabbit iliac artery stenting has become an accepted alternative. After widespread clinical use of DES, an unforeseen complication arose: late stent thrombosis. In a back-to-bench step, some data from animal models helped to explain the phenomenon. A delayed and incomplete vascular healing was detected. Toxic and hypersensitivity reactions to polymers and/or drugs seem to be the underlying causes. So, translational research focused on the safety aspect of these devices: development of better drug carriers as absorbable polymers or fully bioresorbable scaffolds, selection of different drugs and assessment of the re-endothelialization process. We review and evaluate the efficacy and safety of coronary stents in different animal models. Further improvements in this field such as, the selection of better animal models (e.g. hyperlipidemic, diabetic, atherosclerotic) that closely mimic the clinical setting and longer follow-up periods to detect late complications are also discussed.

Perivascular inflammatory cells in ovine Visna/maedi encephalitis and their possible role in virus infection and lesion progression.

We examined the distribution in the perivascular spaces of Visna/maedi antigen, T cells (CD3+, CD4+ and CD8+), B cells and macrophages by immunohistochemistry in 22 natural cases of Visna/maedi encephalitis. Sheep showed lymphocytic or histiocytic lesions. In mild lymphocytic lesions, the viral antigen was detected in perivascular cuffs where CD8+ T cells predominated, but in severe lymphocytic lesions, sparse antigen was identified, and CD8+/CD4+ T cells appeared in a similar proportion in multilayer perivascular sleeves. In histiocytic lesions, vessels were surrounded by macrophages with abundant viral antigen, with CD8+/CD4+ T cells and B cells in the periphery. These results could reflect different stages of virus neuroinvasion and clarify the neuropathogenesis of Visna/maedi encephalitis.

Vasomotor response to different endothelium-dependent vasodilators in an animal model.

BACKGROUND AND OBJECTIVES: Incomplete re-endothelialization of stents can be revealed as paradoxical vasoconstriction with endothelium-dependent vasodilators. As no consensus exists about the best method or agent, our objective is to analyze the response to different drugs in a coronary swine model. METHODS: Twenty-seven stents were implanted in 9 domestic swine. The vessel diameter of proximal and distal segments (≥5 mm) was assessed immediately post implantation. Different endothelium-dependent vasodilators were used: intracoronary (IC) acetylcholine, 20 µg (A2) and 40 µg (A4), IC serotonin (S), 100 µg, and isoproterenol (I), intravenous infusion. The results are presented as constriction (%) compared with maximal vasodilation with IC nitroglycerin (N, 200 µg). RESULTS: In 10 vessels (37%), A4 provoked an occlusive spasm. Acetylcholine induced a higher degree of vasoconstriction (A4, 42 ± 39%; A2, 16 ± 14%) than the rest of the agonists (S, 6 ± 12%; I, 6 ± 11%; P<.01). The constriction rate was not related to the induced hemodynamic changes. CONCLUSIONS: After focal endothelial denudation in a coronary swine model, the constriction rate induced by different endothelium-dependent vasodilators is highly variable. The highest value is observed after IC acetylcholine bolus. The constriction rate does not correlate with the observed hemodynamic changes.

Análisis de la inflamación luminal inducida por distintos tipos de stent coronario en el modelo coronario animal mediante microscopía electrónica de barrido / Scanning electron microscopy analysis of luminal inflammation induced by different types of coronary stent in an animal model

Los stents farmacoactivos se asocian con retraso en la endotelización y fenómenos inflamatorios persistentes demostrados histológicamente. En la superficie luminal, mediante microscopio electrónico de barrido se observan también cúmulos de células inflamatorias. Para cuantificar esta respuesta inflamatoria se implantaron un stent de acero y dos stents farmacoactivos con distintas dosis de vinblastina y el mismo polímero en las coronarias de 12 cerdos domésticos. Se analizó 3 y 7 días después la densidad de células inflamatorias por área representativa (100 x 100 mm). La endotelización del stent de acero fue más completa que en los stents farmacoactivos a los 3 días (p=0,016) y a los 7 días (p=0,0001). Los stents farmacoactivos indujeron un grado de inflamación mayor que los stents de acero a los 3 días (11,8±3.5% frente al 4,5±2%; p=0,001) y a los 7 días (26,3±4,4% frente al 1,2±1,5%; p=0,0001), con un patrón opuesto: la respuesta inflamatoria aumentaba con el tiempo en los stents farmacoactivos, al contrario de lo que sucedía con los stents de acero (AU)

There is histological evidence that drug-eluting stents are associated with delayed endothelialization and a persistent inflammatory state. Moreover, clusters of inflammatory cells have been observed on luminal surfaces by scanning electron microscopy. With the aim of quantifying this inflammatory response, we implanted one bare-metal stent and two drug-eluting stents containing different doses of vinblastine embedded in the same polymer into the coronary arteries of 12 domestic pigs. The density of inflammatory cells in a representative area (100 x 100 mm) was quantified at 3 and 7 days. Endothelialization was more complete in bare-metal stents than in drug-eluting stents at both 3 days (P = .016) and 7 days (P = .0001). The degree of inflammation induced by the drug-eluting stents was higher than that induced by the bare-metal stents at both 3 days (11.8 +/- 3.5% vs. 4.5 +/- 2%; P = .001) and 7 days (26.3 +/- 4.4% vs. 1.2 +/- 1.5%; P = .0001). In addition, the time sequence was inverted: the inflammatory response increased over time with the drug-eluting stents, while the opposite occurred with the bare-metal stents (AU)

Scanning electron microscopy analysis of luminal inflammation induced by different types of coronary stent in an animal model.

There is histological evidence that drug-eluting stents are associated with delayed endothelialization and a persistent inflammatory state. Moreover, clusters of inflammatory cells have been observed on luminal surfaces by scanning electron microscopy. With the aim of quantifying this inflammatory response, we implanted one bare-metal stent and two drug-eluting stents containing different doses of vinblastine embedded in the same polymer into the coronary arteries of 12 domestic pigs. The density of inflammatory cells in a representative area (100 x 100 µm) was quantified at 3 and 7 days. Endothelialization was more complete in bare-metal stents than in drug-eluting stents at both 3 days (P=.016) and 7 days (P=.0001). The degree of inflammation induced by the drug-eluting stents was higher than that induced by the bare-metal stents at both 3 days (11.8±3.5% vs. 4.5±2%; P=.001) and 7 days (26.3±4.4% vs. 1.2±1.5%; P=.0001). In addition, the time sequence was inverted: the inflammatory response increased over time with the drug-eluting stents, while the opposite occurred with the bare-metal stents.

Development and characterization of protective Haemophilus parasuis subunit vaccines based on native proteins with affinity to porcine transferrin and comparison with other subunit and commercial vaccines.

Haemophilus parasuis is the agent responsible for causing Glässer's disease, which is characterized by fibrinous polyserositis, polyarthritis, and meningitis in pigs. In this study, we have characterized native outer membrane proteins with affinity to porcine transferrin (NPAPT) from H. parasuis serovar 5, Nagasaki strain. This pool of proteins was used as antigen to developed two vaccine formulations: one was adjuvanted with a mineral oil (Montanide IMS 2215 VG PR), while the other was potentiated with a bacterial neuraminidase from Clostridium perfringens. The potential protective effect conferred by these two vaccines was compared to that afforded by two other vaccines, consisting of recombinant transferrin-binding protein (rTbp) A or B fragments from H. parasuis, Nagasaki strain, and by a commercially available inactivated vaccine. Five groups of colostrum-deprived piglets immunized with the vaccines described above, one group per each vaccine, and a group of nonvaccinated control animals were challenged intratracheally with a lethal dose (3 × 108 CFU) of H. parasuis, Nagasaki strain. The two vaccines containing rTbps yielded similar results with minimal protection against death, clinical signs, gross and microscopic lesions, and H. parasuis invasion. In contrast, the two vaccines composed of NPAPT antigen and commercial bacterin resulted in a strong protection against challenge (without deaths and clinical signs), mild histopathological changes, and no recovery of H. parasuis, thus suggesting their effectiveness in preventing Glässer's disease outbreaks caused by serovar 5.