Environmental practices related to the inhalation of airborne dust have been identified as the main cause of equine asthma (EA) and reasonably, they are truly relevant in its treatment and control, especially for horses with its severe form. Vast research regarding environmental recommendations has been conducted in recent years. However, no recent exhaustive reviews exist that gather all this new evidence. The aim of this review is to report and compare the most pertinent information concerning the environmental management of EA. The main findings highlight the importance of the type of forage used for feeding but also its method of production and possible contamination during manufacture and/or storage. Procedures to reduce this, such as soaking and steaming hay, improve its hygienic quality, although they also decrease forage’s nutritional value, making dietetic supplementation necessary. Regarding stabling, despite some conflicting results, avoiding straw as bedding and improving barn ventilation continue to be the common recommendations if turning to pasture is not feasible. Finally, owners’ compliance has been identified as the most critical point in correct environmental control. Educating owners about the genuine benefits of these measures should be a cornerstone of EA management.

Obesity and its associated complications, such as metabolic syndrome, are an increasing problem in both humans and horses in the developed world. The expression patterns of resistin differ considerably between species. In rodents, resistin is expressed by adipocytes and is related to obesity and ID. In humans, resistin is predominantly produced by inflammatory cells, and resistin concentrations do not reflect the degree of obesity, although they may predict cardiovascular outcomes. The aim of this study was to investigate the usefulness of resistin and its relationship with ID and selected indicators of inflammation in horses. Seventy-two horses, included in one of the four following groups, were studied: healthy controls (C, n = 14), horses with inflammatory conditions (I, n = 21), horses with mild ID (ID1, n = 18), and horses with severe ID (ID2, n = 19). Plasma resistin concentrations were significantly different between groups and the higher values were recorded in the I and ID2 groups (C: 2.38 ± 1.69 ng/mL; I: 6.85 ± 8.38 ng/mL; ID1: 2.41 ± 2.70 ng/mL; ID2: 4.49 ± 3.08 ng/mL). Plasma resistin was not correlated with basal insulin concentrations. A significant (r = 0.336, p = 0.002) correlation was found between resistin and serum amyloid A. Our results show that, as is the case in humans, plasma resistin concentrations in horses are predominantly related to inflammatory conditions and not to ID. Horses with severe ID showed an elevation in resistin that may be secondary to the inflammatory status associated with metabolic syndrome.

Equine Metabolic Syndrome (EMS) is a complex endocrine disorder characterized by insulin dysregulation (ID), and an increased risk of developing laminitis, often accompanied by generalized or regional adiposity. Despite growing awareness of EMS, early and accurate diagnosis remains challenging. In this pilot study, we investigated changes in the levels of circulating microRNAs (miRNAs) in plasma samples from horses diagnosed with EMS (n=13), compared to overweight/obese (OW/OB) non-ID horses (n=16) and healthy controls (n=16). Using a targeted OpenArray, followed by a Kruskal-Wallis and Dunn's post hoc tests, we identified four miRNAs that were differentially expressed across the groups: miR-221, which was increased in EMS group vs healthy (p value= 0.013), miR-132, which was increased in OW/OB non-ID group vs both EMS and healthy (p value= 0.048 for both comparisons) and, miR-186 and miR-15a, which were increased in healthy controls vs EMS (p value = 0.019 for miR-186 and p value = 0.032 for miR-15a) and OW/OB non-ID (p value = 0.001 for miR-186 and p value = 0.009 for miR-15a). Functional enrichment analysis of their putative target genes revealed involvement in key insulin signalling mechanisms, including phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (AKT), AMP-activated protein kinase (AMPK) and forkhead box O protein (FOXO) signalling pathways. Receiver Operating Characteristic (ROC) curve analysis demonstrated that combinations of these miRNAs provided discriminatory power between clinical groups (AUCs ranging from 0.79 to 0.93). These findings support the potential of circulating miRNA levels as non-invasive predictive biomarkers for EMS development. Moreover, the signalling pathways identified provide mechanistic insight and establish a foundation for future studies aimed at therapeutic target discovery.

Equine Metabolic Syndrome (EMS) is a complex endocrine disorder characterized by obesity, insulin dysregulation (ID), and an increased risk of developing laminitis. Despite growing awareness of EMS, early and accurate diagnosis remains challenging. In this study, we investigated changes in the levels of circulating microRNAs (miRNAs) in plasma samples from horses diagnosed with EMS, compared to obese non-ID horses and healthy controls. Using a targeted real-time PCR OpenArray, we identified four miRNAs —miR-221, miR-186, miR-132, and miR-15a— that were differentially expressed across the groups. Functional enrichment analysis of their validated target genes revealed involvement in key insulin signalling mechanisms, including phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (AKT), AMP-activated protein kinase (AMPK) and forkhead box O protein (FOXO) signalling pathways. Receiver Operating Characteristic (ROC) curve analysis demonstrated that combinations of these miRNAs provided discriminatory power between clinical groups (AUCs ranging from 0.79 to 0.93). These findings support the potential of circulating miRNA levels as non-invasive predictive biomarkers for EMS and related metabolic dysfunctions. Moreover, the signalling pathways identified provide mechanistic insight and establish a foundation for future studies aimed at therapeutic target discovery.