Disorders of the Respiratory System

Welfare of equidae during transport

In the framework of its Farm to Fork Strategy, the Commission is undertaking a comprehensive evaluation of animal welfare legislation. This opinion deals with the protection of horses and donkeys during transport. While the opinion focuses primarily on road transport of horses, there are specific sections dealing with the transport of horses on roll-on-roll-off ferries, horses transported by air and the transport of donkeys. In addition, the opinion covers welfare concerns in relation to a specific scenario identified by the European Commission related to the transport of horses on long journeys to slaughterhouses. Current practices related to transport of horses during the different stages (preparation, loading and unloading, transit and the journey breaks) are described. Overall, 13 welfare consequences were identified as being highly relevant for the welfare of horses during transport based on severity, duration and frequency of occurrence: gastro-enteric disorders, handling stress, heat stress, injuries, isolation stress, motion stress, prolonged hunger, prolonged thirst, respiratory disorders, resting problems, restriction of movement, sensory overstimulation and separation stress. These welfare consequences and their animal-based measures are described. A variety of hazards were identified related to factors such as inexperienced/untrained handlers, lack of horse training, structural deficiencies of vehicles/facilities, poor driving skills/conditions, horse separation/regrouping, unfavourable microclimatic and environmental conditions and poor husbandry practices. The opinion contains general and specific conclusions in relation to the different stages of transport. Recommendations to prevent hazards and correct or mitigate welfare consequences have been developed. Recommendations were also developed to define quantitative thresholds for microclimatic conditions within the means of transport and for space allowance. The development of welfare consequences over time was assessed in relation to maximum journey time.

Bacterial Toxins from Staphylococcus aureus and Bordetella bronchiseptica Predispose the Horse's Respiratory Tract to Equine Herpesvirus Type 1 Infection

Respiratory disease in horses is caused by a multifactorial complex of infectious agents and environmental factors. An important pathogen in horses is equine herpesvirus type 1 (EHV-1). During co-evolution with this ancient alphaherpesvirus, the horse’s respiratory tract has developed multiple antiviral barriers. However, these barriers can become compromised by environmental threats. Pollens and mycotoxins enhance mucosal susceptibility to EHV-1 by interrupting cell junctions, allowing the virus to reach its basolateral receptor. Whether bacterial toxins also play a role in this impairment has not been studied yet. Here, we evaluated the role of α-hemolysin (Hla) and adenylate cyclase (ACT), toxins derived from the facultative pathogenic bacterium Staphylococcus aureus (S. aureus) and the primary pathogen Bordetella bronchiseptica (B. bronchiseptica), respectively. Equine respiratory mucosal explants were cultured at an air–liquid interface and pretreated with these toxins, prior to EHV-1 inoculation. Morphological analysis of hematoxylin–eosin (HE)-stained sections of the explants revealed a decreased epithelial thickness upon treatment with both toxins. Additionally, the Hla toxin induced detachment of epithelial cells and a partial loss of cilia. These morphological changes were correlated with increased EHV-1 replication in the epithelium, as assessed by immunofluorescent stainings and confocal microscopy. In view of these results, we argue that the ACT and Hla toxins increase the susceptibility of the epithelium to EHV-1 by disrupting the epithelial barrier function. In conclusion, this study is the first to report that bacterial exotoxins increase the horse’s sensitivity to EHV-1 infection. Therefore, we propose that horses suffering from infection by S. aureus or B. bronchiseptica may be more susceptible to EHV-1 infection.

Distinct JNK/VEGFR signaling on angiogenesis of breast cancer-associated pleural fluid based on hormone receptor status

Malignant pleural effusion is a common complication in metastatic breast cancer (MBC); however, changes in the pleural microenvironment are poorly characterized, especially with respect to estrogen receptor status. Histologically, MBC presents with increased microvessels beneath the parietal and visceral pleura, indicating generalized angiogenic activity. Breast cancer‐associated pleural fluid (BAPF) was collected and cultured with HUVECs to recapitulate the molecular changes in subpleural endothelial cells. The clinical progression of triple‐negative breast cancer (TNBC) is much more aggressive than that of hormone receptor‐positive breast cancer (HPBC). However, BAPF from HPBC (BAPF‐HP) and TNBC (BAPF‐TN) homogeneously induced endothelial proliferation, migration, and angiogenesis. In addition, BAPF elicited negligible changes in the protein marker of endothelial‐mesenchymal transition. Both BAPF‐HP and BAPF‐TN exclusively upregulated JNK signaling among all MAPKs in HUVECs. By contrast, the response to the JNK inhibitor was insignificant in Transwell and tube formation assays of the HUVECs cultured with BAPF‐TN. The distinct contribution of p‐JNK to endothelial angiogenesis was consequently thought to be induced by BAPF‐HP and BAPF‐TN. Due to increased angiogenic factors in HUVECs cultured with BAPF, vascular endothelial growth factor receptor 2 (VEGFR2) inhibitor was applied accordingly. Responses to VEGFR2 blockade were observed in both BAPF‐HP and BAPF‐TN concerning endothelial migration and angiogenesis. In conclusion, the above results revealed microvessel formation in the pleura of MBC and the underlying activation of p‐JNK/VEGFR2 signaling. Distinct responses to blocking p‐JNK and VEGFR2 in HUVECs cultured with BAPF‐HP or BAPF‐TN could lay the groundwork for future investigations in treating MBC based on hormone receptor status.