Measurement of Plasma Resistin Concentrations in Horses with Metabolic and Inflammatory Disorders

Abstract

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.

Bringing equine adipose tissue into focus

“…Numerous human studies have failed to demonstrate a reliable association between resistin levels, obesity and/or insulin dysregulation. In contrast, resistin may be a marker of inflammation (Banerjee & Lazar, 2003), consistent with recent findings in horses (Fuentes‐Romero et al, 2021).…”

Bringing equine adipose tissue into focus

“…Numerous human studies have failed to demonstrate a reliable association between resistin levels, obesity and/or insulin dysregulation. In contrast, resistin may be a marker of inflammation (Banerjee & Lazar, 2003), consistent with recent findings in horses (Fuentes-Romero et al, 2021).…”

A one-health approach to identifying and mitigating the impact of endocrine disorders on human and equine athletes

“…In horses with ID, resistin was elevated in plasma, which was attributed to the inflammatory nature of severe ID, and evaluation of its presence in equine synovial fluid and synovium should be examined. 124 While other traditional biomarkers for OA should be evaluated in ID and metabolically healthy horses, 109,125,126 future research for novel biomarkers should also include assessment with the multiomic approaches as discussed below. 127…”