Lipopolysaccharide (LPS) is a component of the outer membrane of Gram-negative bacteria and acts as an endotoxin when encountered by horses. It is recognized by the equine immune system and can trigger a strong inflammatory response. LPS exposure is often associated with conditions such as endotoxemia and sepsis in horses, where it can contribute to systemic inflammation and other clinical symptoms. This page aggregates peer-reviewed research studies and scholarly articles that explore the mechanisms of LPS recognition in horses, its effects on equine health, and its role in disease processes.
Parkinson NJ, Buechner-Maxwell VA, Witonsky SG, Pleasant RS, Werre SR, Ahmed SA.The innate immune response to lipopolysaccharide contributes substantially to the morbidity and mortality of gram-negative sepsis. Horses and humans share an exquisite sensitivity to lipopolysaccharide and thus the horse may provide valuable comparative insights into this aspect of the inflammatory response. MicroRNAs, small non-coding RNA molecules acting as post-transcriptional regulators of gene expression, have key roles in toll-like receptor signaling regulation but have not been studied in this context in horses. The central hypothesis of this study was that lipopolysaccharide induces di...
Abdelhamid L, Hussein H, Ghanem M, Eissa N.Retinoic acid (RA), an active metabolite of vitamin A, has shown potential therapeutic immunomodulatory properties. Allogeneic mesenchymal stem cells (MSCs)-based therapy is an effective approach to induce tissue healing and regeneration in many equine orthopedic conditions. However, MSCs-based therapies induced inflammatory responses in vivo. This study aimed to: 1. Determine the effect of RA cell culture treatment on inflammatory responses of lipopolysaccharides (LPS)- and allogeneic MSCs-stimulated peripheral blood mononuclear cells (PBMCs). 2. Determine the effect of RA on stimulated MSCs ...
Kilborne AH, Hussein H, Bertone AL.OBJECTIVE To investigate effects of hyaluronic acid (HA) or HA combined with chondroitin sulfate (CS) and N-acetyl-d-glucosamine (NAG) by use of a lipopolysaccharide (LPS) in vitro method. SAMPLE Monolayer cultures of synovial cells from 4 adult horses. PROCEDURES Synovial cell cultures were untreated or treated with HA alone or HA-CS-NAG for 24 hours, subsequently unchallenged or challenge-exposed with 2 LPS concentrations (20 and 50 ng/mL) for 2 hours, and retreated with HA or HA-CS-NAG for another 24 hours. Cellular morphology of cultures was evaluated at 0, 24 (before LPS), 26 (after LPS),...
Kahn MK, Coverdale JA, Leatherwood JL, Arnold CE, Dabareiner RA, Bradbery AN, Millican AA, Welsh TH.Eighteen Quarter Horses were used in a randomized complete design for a 28-d experiment to evaluate age-related effects on inflammation and cartilage turnover after induction of a single inflammatory insult using lipopolysaccharide (LPS). Horses were grouped by age as yearlings (3 males and 3 females), 2 to 3 yr olds (2/3 yr old; 2 males and 4 females), and skeletally mature 5 to 8 yr olds (mature; 2 males and 4 females). On d 0, all horses were individually housed and fed diets that met or exceeded requirements. On d 14, horses were challenged with an intra-articular injection of LPS. Radial ...
Frondoza CG, Fortuno LV, Grzanna MW, Ownby SL, Au AY, Rashmir-Raven AM.Objective Pro-inflammatory mediators such as prostaglandin E-2 (PGE2) play major roles in the pathogenesis of osteoarthritis (OA). Although current pharmacologic treatments reduce inflammation, their prolonged use is associated with deleterious side effects prompting the search for safer and effective alternative strategies. The present study evaluated whether chondrocyte production of PGE2 can be suppressed by the combination of avocado/soybean unsaponifiables (ASU) and α-lipoic acid (LA). Design Chondrocytes from articular cartilage of equine joints were incubated for 24 hours with: (1) con...
Pacholewska A, Marti E, Leeb T, Jagannathan V, Gerber V.Lipopolysaccharide (endotoxin, LPS) is a strong inducer of the innate immune response. It is widespread in our environment, e.g. in house dust and contributes to asthma. Compared to humans, horses are even more sensitive to LPS. However, data on LPS effects on the equine transcriptome are very limited. Using RNA-seq we analysed LPS-induced differences in the gene expression in equine peripheral blood mononuclear cells at the gene and gene-network level in two half-sib families and one group of unrelated horses. 24 h-LPS challenge of equine immune cells resulted in substantial changes in the t...
Bonelli F, Meucci V, Divers TJ, Wagner B, Intorre L, Sgorbini M.Endotoxemia represents a significant clinical and economic problem for the equine industry. This study assesses the kinetics of soluble CD14 (sCD14), chemokine (CC motif) ligand 2 (CCL2), interleukin 10 (IL-10) and plasma procalcitonin (PCT) in healthy horses after the intravenous infusion of lipopolysaccharide (LPS). The aim was to contribute to the basic understanding of the equine species-specific kinetics of these molecules in response to LPS exposure, which could support further findings in clinical studies and identify valuable inflammatory biomarkers for equine practice. Eleven healthy ...
van de Water E, Oosterlinck M, Dumoulin M, Korthagen NM, van Weeren PR, van den Broek J, Everts H, Pille F, van Doorn DA.Nutraceuticals are often used in the management of equine osteoarthritis, but scientific evidence of their efficacy is lacking. Objective: To study the preventive effects of two new nutraceuticals after the experimental induction of synovitis in comparison with positive and negative control treatments. Methods: Blinded, controlled, randomised experiment. Methods: Twenty-four healthy Standardbred horses were randomly allocated to supplement AT (multi-ingredient, 28 days), supplement HP (collagen hydrolysate, 60 days), meloxicam (4 days) or placebo (60 days). Synovitis was induced in the right i...
Leatherwood JL, Gehl KL, Coverdale JA, Arnold CE, Dabareiner RA, Walter KN, Lamprecht ED.Fourteen yearling Quarter horses (351 to 470 kg) were utilized in a randomized complete block design to evaluate potential of glucosamine hydrochloride (HCl) to mitigate intra-articular inflammation following a single inflammatory insult. Horses were blocked by BW, age, and sex, and randomly assigned to treatments for a 98-d experiment. Treatments consisted of a control diet (CON; = 7) fed 1% BW per d (as-fed) of concentrate only or a treatment diet ( = 7) of concentrate top dressed with 30 mg/kg BW glucosamine HCl (99.6% purity; GLU30) offered at 12 h intervals. Horses were maintained in indi...
Ludwig EK, Brandon Wiese R, Graham MR, Tyler AJ, Settlage JM, Werre SR, Petersson-Wolfe CS, Kanevsky-Mullarky I, Dahlgren LA.To investigate the serum and synovial fluid serum amyloid A (SAA) response in equine models of synovitis and septic arthritis and to compare handheld and validated immunoturbidometric assays for SAA quantification. Methods: Controlled, experimental study. Methods: Healthy adult horses (n = 9). Methods: Synovitis (n = 4) and septic arthritis (n = 5) were induced using lipopolysaccharide and Staphylococcus aureus, respectively, and serial serum and synovial fluid samples were collected. Serial synovial fluid cytology was performed for both models and synovial fluid from the septic ar...
Karagianni AE, Kapetanovic R, Summers KM, McGorum BC, Hume DA, Pirie RS.Alveolar macrophages (AMs) are the first line of defence against pathogens in the lungs of all mammalian species and thus may constitute appropriate therapeutic target cells in the treatment and prevention of opportunistic airway infections. Therefore, acquiring a better understanding of equine macrophage biology is of paramount importance in addressing this issue in relation to the horse. Objective: To compare the transcriptome of equine AMs with that of equine peritoneal macrophages (PMs) and to investigate the effect of lipopolysaccharide (LPS) on equine AM. Methods: Gene expression study o...
Carmona JU, Ríos DL, López C, Álvarez ME, Pérez JE, Bohórquez ME.Platelet-rich plasma (PRP) preparations are a common treatment in equine osteoarthritis (OA). However, there are controversies regarding the ideal concentration of platelets and leukocytes in these biological substances necessary to induce an adequate anti-inflammatory and anabolic response in articular cartilage. The aims were to study the influence of leukocyte- and platelet-rich gel (L-PRG) and pure platelet-rich gel (P-PRG) supernatants on the histological changes of cartilage, the degree of chondrocyte apoptosis, the production of hyaluronan (HA) and the gene expression of nuclear factor ...
Rütten S, Schusser GF, Abraham G, Schrödl W.Horses are much predisposed and susceptible to excessive and acute inflammatory responses that cause the recruitment and stimulation of polymorphnuclear granulocytes (PMN) together with peripheral blood mononuclear cells (PBMC) and the release of cytokines. The aim of the study is to develop easy, quick, cheap and reproducible methods for measuring tumor necrosis factor alpha (TNF-α) and interleukin-1 receptor antagonist (IL-1Ra) in the equine whole blood cultures ex-vivo time- and concentration-dependently. Results: Horse whole blood diluted to 10, 20 and 50 % was stimulated with lipopolysa...
Vinther AM, Heegaard PM, Skovgaard K, Buhl R, Andreassen SM, Andersen PH.Local inflammation may progress into systemic inflammation. To increase our understanding of the basic immunological processes during transition of equine local inflammation into a systemic state, investigation into the equine systemic immune response to local inflammation is warranted. Therefore, the aim of this study was to investigate the innate peripheral blood leukocyte (PBL) immune response to local inflammation in horses, and to compare this response with the PBL immune response during the early phase of acute systemic inflammation. Expression of 22 selected inflammation-related genes w...
Anderson SL, Singh B.Horses that develop colitis invariably exhibit signs of a systemic inflammatory response syndrome (SIRS). A significant contributor to the development of SIRS in human subjects is delayed neutrophil apoptosis, but this has not been specifically studied in horses. Objective: To determine the occurrence of ex vivo neutrophil apoptosis and its contribution to the development of SIRS in an equine colitis model. Methods: Experiment using a colitis model. Methods: Neutrophils were isolated before and after the induction of colitis using an oligofructose overdose model, placed into culture for 12 h o...
Fogle J, Jacob M, Blikslager A, Edwards A, Wagner B, Dean K, Fogle C.Clinically useful biomarkers are needed for early identification of endotoxaemic horses. Soluble CD14 (sCD14) is amplified early in response to inflammatory signals, including bacterial lipopolysaccharide (LPS), and may prove a useful biomarker for clinical endotoxaemia. Objective: The aim of this study was to determine if sCD14 could serve as a more reliable biomarker of the clinical signs of endotoxaemia, compared to measuring LPS alone. Methods: Prospective observational study in horses at a veterinary teaching hospital. Methods: Plasma samples were collected from 20 healthy horses and 35 h...
Martin LM, Johnson PJ, Amorim JR, Honaker AR, Donaldson RS, DeClue AE.Horses affected with gastrointestinal conditions such as colic or colitis are at substantial risk for translocation of bacterial components such as lipopolysaccharide (LPS, endotoxin) from the gastrointestinal tract into circulation resulting in systemic inflammation and subsequent morbidity and mortality. Therefore, there is a need for effective preventive and treatment strategies aimed at minimizing the host's inflammatory reaction to these pathogen-associated molecular patterns (PAMPs) from gastrointestinal disease. Resveratrol (RES, trans-3,5,4'-trihydroxystilbene) is a phytoalexin commonl...
Holcombe SJ, Jacobs CC, Cook VL, Gandy JC, Hauptman JG, Sordillo LM.Endotoxemia models are used to study mechanisms and treatments of early sepsis. Repeated endotoxin exposures induce periods of endotoxin tolerance, characterized by diminished proinflammatory responses to lipopolysaccharide (LPS) and modulated production of proinflammatory cytokines. Repeated measure designs using equine endotoxemia models are rarely performed, despite the advantages associated with reduced variability, because the altered responsiveness would confound study results and because the duration of equine endotoxin tolerance is unknown. We determined the interval of endotoxin toler...
Lange-Consiglio A, Perrini C, Tasquier R, Deregibus MC, Camussi G, Pascucci L, Marini MG, Corradetti B, Bizzaro D, De Vita B, Romele P, Parolini O....Administration of horse amniotic mesenchymal cells (AMCs) and their conditioned medium (AMC-CM) improves the in vivo recovery of spontaneous equine tendon lesions and inhibits in vitro proliferation of peripheral blood mononuclear cells (PBMC). This process may involve microvesicles (MVs) as an integral component of cell-to-cell communication during tissue regeneration. In this study, the presence and type of MVs secreted by AMCs were investigated and the response of equine tendon cells to MVs was studied using a dose-response curve at different concentrations and times. Moreover, the ability ...
Barton MH, Darden JE, Clifton S, Vandenplas M.To validate primer sets for use in reverse transcription quantitative PCR assays to measure gene expression of cytosolic phospholipase A2 (cPLA2) and microsomal prostaglandin E2 synthase 1 (mPGES1) in equine mononuclear cells and determine the effects of firocoxib, a selective cyclooxygenase 2 (COX-2) inhibitor, on COX-2, cPLA2, and mPGES1 gene expression following incubation of mononuclear cells with lipopolysaccharide (LPS). Methods: 8 healthy adult horses. Methods: Peripheral blood mononuclear cells were isolated by density gradient centrifugation and incubated at 37°C with medium alone, f...
Reisinger N, Schaumberger S, Nagl V, Hessenberger S, Schatzmayr G.Laminitis is one of the most common diseases in horses. It is not only painful for the animal, but also has a significant financial impact on the equine industry. This multifactorial disease affects the connective tissue of the hoof. However, the pathogenesis of laminitis is still not fully understood. Endotoxins, also known as lipopolysaccharides (LPS), and bacterial exotoxins seem to play an important role during the development of laminitis. The aim of our study was to investigate the effect of increasing LPS concentrations (0, 2.5, 5, 10, and 100 μg/mL) on cell viability of isolated epide...
Pacholewska A, Jagannathan V, Drögemüller M, Klukowska-Rötzler J, Lanz S, Hamza E, Dermitzakis ET, Marti E, Leeb T, Gerber V.Recurrent airway obstruction (RAO) is a common and potentially debilitating lower airway disease in horses, which shares many similarities with human asthma. In susceptible horses RAO exacerbation is caused by environmental allergens and irritants present in hay dust. The objective of this study was the identification of genes and pathways involved in the pathology of RAO by global transcriptome analyses in stimulated peripheral blood mononuclear cells (PBMCs). We performed RNA-seq on PBMCs derived from 40 RAO affected and 45 control horses belonging to three cohorts of Warmblood horses: two h...
Williams LB, Koenig JB, Black B, Gibson TW, Sharif S, Koch TG.Improvement has been reported following intra-articular (i.a.) injection of mesenchymal stromal cells (MSCs) in several species. These observations have led to the use of i.a. MSCs in equine practice with little understanding of the mechanisms by which perceived improvement occurs. Objective: To evaluate the effect of i.a. allogeneic umbilical cord blood (CB-) derived MSCs using a lipopolysaccharide (LPS) induced synovitis model. We hypothesised that i.a. CB-MSCs would reduce the inflammatory response associated with LPS injection. Methods: Randomised, blinded experimental study. Methods: Feas...
Ríos DL, López C, Carmona JU.To study, in normal cartilage explants (CEs) challenged with lipopolysaccharide (LPS), the temporal effects (at 48 and 96h) of leukocyte- and platelet-rich gel (L-PRG) and pure platelet-rich gel (P-PRG) supernatants on the production and degradation of platelet-associated growth factors (GFs) (platelet-derived GF isoform BB [PDGF-BB] and transforming growth factor beta-1 [TGF-β1]), pro-inflammatory (tumour necrosis factor alpha [TNF-α]) and anti-inflammatory cytokines (interleukin 4 [IL-4] and IL-1 receptor antagonist [IL-1ra]). Methods: CEs from six horses were challenged with LPS and cultu...
Andreassen SM, Berg LC, Nielsen SS, Kristensen AT, Jacobsen S.Studies in humans have shown that haemostatic and inflammatory pathways both play important roles in the pathogenesis of joint disease. The aim of this study was to assess mRNA expression of haemostatic and inflammatory factors in cultured equine fibroblast-like synoviocytes exposed to lipopolysaccharide (LPS), fibrinogen and thrombin. Synovial membranes were collected from metacarpo-phalangeal joints of 6 skeletally mature horses euthanized for non-orthopaedic reasons. Passage 4 fibroblast-like synoviocytes were left non-treated or treated with either 0.1 μg/ml LPS, 5 mg/ml fibrinogen or 5 U...
Ríos DL, López C, Álvarez ME, Samudio IJ, Carmona JU.Platelet-rich plasma (PRP) preparations are a common treatment in osteoarthritis (OA) and inflammatory synovitis. However, there is ambiguity regarding the ideal concentration of leukocytes and platelets in these preparations necessary to induce an adequate anti-inflammatory and anabolic response in joint tissues, such as the synovial membrane. This research aimed to study, in normal synovial membrane explants (SME) challenged with lipopolysaccharide (LPS), the temporal effects (at 48 and 96h) of leukocyte- and platelet-rich gel (L-PRG) and pure platelet-rich gel (P-PRG) supernatants on the pr...
Smyth TT, Carmalt JL, Treen TT, Lanovaz JL.Diseases of the temporomandibular joint (TMJ) are well reported in man and some domestic animals other than the horse. The pathophysiology of equine TMJ disease and the effects of disease on the kinematics of mastication are unknown. Objective: To determine whether transient unilateral inflammation of the equine TMJ results in alterations in the masticatory cycle. Methods: An experimental controlled study utilising 6 horses of various ages with normal dentition. Methods: Each horse was equipped with an optical motion tracking (kinematic) system. Horses were observed chewing grass hay over 3 m...
Vinther AM, Skovgaard K, Heegaard PM, Andersen PH.In horses, insights into the innate immune processes in acute systemic inflammation are limited even though these processes may be highly important for future diagnostic and therapeutic advances in high-mortality disease conditions as the systemic inflammatory response syndrome (SIRS) and sepsis. Therefore, the aim of this study was to investigate the expression of 31 selected blood leukocyte immune genes in an equine model of acute systemic inflammation to identify significantly regulated genes and to describe their expression dynamics during a 24-h experimental period. Systemic inflammation ...
Sandersen C, Bienzle D, Cerri S, Franck T, Derochette S, Neven P, Mouytis-Mickalad A, Serteyn D.Horses commonly suffer from chronic respiratory disease and are also used in large animal models of spontaneous or induced airway inflammation. The anti-inflammatory properties of curcumin are largely described but its low bioavailability precludes its clinical use. NDS27, a lysin salt of curcumin incorporated in beta-cyclodextrine, has high bioavailability and can be administered by inhalation. The aim of this study was to investigate the effects of inhaled NDS27 on inflammatory cytokines and proteins in the broncho-alveolar lavage fluid using a model of neutrophilic airway inflammation. Meth...
Carregaro AB, Freitas GC, Ribeiro MH, Xavier NV, Dória RG.Continuous-rate infusion (CRI) of drugs results in more stable plasma drug concentrations than administration of intermittent boluses, thus providing greater stability of physiological parameters. The aim of this study was to evaluate the physiologic and analgesic effects of the administration of morphine, butorphanol, tramadol or methadone by CRI in horses with induced synovitis of the radiocarpal joint. Results: Increased values of cardiorespiratory parameters and body temperature were observed in all groups after initiation of opioid administration, and these increases were sustained throug...
Lavoie-Lamoureux A, Beauchamp G, Quessy S, Martin JG, Lavoie JP.To compare innate immune responses of peripheral blood leukocytes from healthy and asymptomatic heaves-affected horses. Methods: Heaves-affected horses (n=5-6) and healthy controls (n=4-5) kept under low dust environments (pasture or shavings and pellets). Methods: Blood neutrophil and neutrophil-depleted cell populations were isolated using MACS system. Cells were incubated with or without bacterial products (lipopolysaccharide (LPS), 100 ng/mL and fMLP, 5 ng/mL, 5 h). Cytokine (IL-1β, IL-8, TNF, IL-4, INFγ and IL-10) and receptor (TLR4) mRNA expression was assessed by qPCR. TNF concentrati...
Kwon S, Gewirtz AT, Hurley DJ, Robertson TP, Moore JN, Vandenplas ML.As sentinel cells of the innate immune system, neutrophils and mononuclear phagocytes use specific TLRs to recognize the conserved molecular patterns that characterize microbes. This study was performed to compare the responses of equine neutrophils and mononuclear phagocytes to LPS and flagellin, components of bacteria that are recognized by TLR4 and TLR5, respectively. Neutrophils and mononuclear phagocytes isolated from healthy horses were incubated in vitro with LPS, flagellin, or pronase-inactivated flagellin in the presence or absence of polymyxin B. Production of reactive oxygen species...
Andreassen SM, Berg LC, Nielsen SS, Kristensen AT, Jacobsen S.Studies in humans have shown that haemostatic and inflammatory pathways both play important roles in the pathogenesis of joint disease. The aim of this study was to assess mRNA expression of haemostatic and inflammatory factors in cultured equine fibroblast-like synoviocytes exposed to lipopolysaccharide (LPS), fibrinogen and thrombin. Synovial membranes were collected from metacarpo-phalangeal joints of 6 skeletally mature horses euthanized for non-orthopaedic reasons. Passage 4 fibroblast-like synoviocytes were left non-treated or treated with either 0.1 μg/ml LPS, 5 mg/ml fibrinogen or 5 U...
Benbarek H, Deby-Dupont G, Caudron I, Grülke S, Deby C, Lamy M, Serteyn D.In horses, the mechanisms of lipopolysaccharide (LPS) stimulation of isolated neutrophils to produce reactive oxygen species remain unknown. We re-investigated this problem by monitoring the luminol-enhanced chemiluminescence (CL) produced by LPS-stimulated equine neutrophils. The neutrophils were isolated from horse blood by discontinuous density gradient centrifugation (> or = 99% neutrophils; viability > or = 98%). Increasing concentrations of Escherichia coli (E. coli) LPS (from 0.01-10 microg ml(-1)) were used to activate the neutrophils. When LPS was used directly, without another ...
Urayama S, Tanaka A, Kusano K, Sato H, Nagashima T, Fukuda I, Fujisawa C, Matsuda H.Nonsteroidal anti-inflammatory drugs such as flunixin meglumine have been used to treat signs of systemic inflammatory conditions, but it is also known to have the side effect to small intestine mucosa. It may be considered to be due to inhibition of both cyclooxygenase (COX)-1 and COX-2. On the other hand, meloxicam is widely used in equine clinical practice and an effective nonsteroidal anti-inflammatory drug with the preferential inhibitory effect on COX-2. However, it has not yet been evaluated in equine systemic inflammation. The aim of this study was to evaluate the effect of meloxicam a...
Figueiredo MD, Moore JN, Vandenplas ML, Sun WC, Murray TF.To evaluate proinflammatory effects of the second-generation synthetic lipid A analogue E5564 on equine whole blood and isolated monocytes and to determine the ability of E5564 to prevent LPS (lipopolysaccharide)-induced procoagulant activity (PCA); tumor necrosis factor (TNF)-alpha production; and mRNA expression of TNF-alpha, interleukin (IL)-1beta, IL-6, and IL-10 by equine monocytes. Methods: Venous blood samples obtained from 19 healthy horses. Methods: Whole blood and monocytes were incubated with Escherichia coli O111:B4 LPS, E5564, or E5564 plus E coli O111:B4 LPS. Whole blood and cell...
Wagner B, Ainsworth DM, Freer H.Soluble CD14 (sCD14) binds bacterial lipopolysaccharide (LPS) and acts as an anti-inflammatory LPS-inhibitor in vivo. In humans, sCD14 is one of the soluble biomarkers used for various inflammatory diseases and conditions, however, sCD14 assays have not yet been evaluated in horses. Here, we developed and optimized a bead-based assay for the quantification of sCD14 in horses. The assay was then used to determine native sCD14 concentrations in serum from healthy and septic foals, in the colostrum of healthy mares and in plasma from adult horses with recurrent airway obstruction (RAO) and contro...
Santos LC, de Moraes AN, Saito ME.To compare the intraarticular (IA) analgesic effects of ropivacaine and morphine in horses with experimentally induced synovitis. Methods: Randomized, blinded cross-over design. Methods: Twelve healthy mixed breed horses between 8-15 years old. Methods: Synovitis was induced in the left radio-carpal joint with an injection of lipopolysaccharide (Escherichia coli 055:B5). Six hours later, the horses were treated with an IA injection of 40 mg of ropivacaine (ROPI), 40 mg of morphine (MOR), 20 mg of ropivacaine added to 20 mg of morphine in saline (RM) or 4 mL of saline (SAL), as control. Analges...
Laan TT, Bull S, Pirie RS, Fink-Gremmels J.To evaluate cytokine production by equine alveolar macrophages after exposure to lipopolysaccharide (LPS), Aspergillus fumigatus, and hay dust, and determine the effect of clenbuterol on the cytokine response. Methods: 6 horses. Methods: Alveolar macrophages were exposed to PBS solution (negative control), LPS, hyphae and conidia of Aspergillus fumigatus (AF), or a suspension of hay dust (HDS) and incubated for 24 hours at 37 degrees C. Concentrations of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta were measured in the supernatant. The procedure was repeated with cells that wer...
Van de Water E, Oosterlinck M, Korthagen NM, Duchateau L, Dumoulin M, van Weeren PR, Olijve J, van Doorn DA, Pille F.An established lipopolysaccharide (LPS) model previously described in Warmbloods, was inconsistent in Standardbred horses, where lameness was not detected despite the presence of synovitis. The present study aimed to determine the dose of LPS from E. coli O55:B5 required to induce mild to moderate lameness following middle carpal joint injection in Standardbred horses and to quantitate the induced lameness over time, with and without anti-inflammatory pre-treatment. In a baseline trial, eight healthy, clinically sound Standardbred horses were used in a rule-based dose-escalation design trial, ...
Fogle J, Jacob M, Blikslager A, Edwards A, Wagner B, Dean K, Fogle C.Clinically useful biomarkers are needed for early identification of endotoxaemic horses. Soluble CD14 (sCD14) is amplified early in response to inflammatory signals, including bacterial lipopolysaccharide (LPS), and may prove a useful biomarker for clinical endotoxaemia. Objective: The aim of this study was to determine if sCD14 could serve as a more reliable biomarker of the clinical signs of endotoxaemia, compared to measuring LPS alone. Methods: Prospective observational study in horses at a veterinary teaching hospital. Methods: Plasma samples were collected from 20 healthy horses and 35 h...
Suagee JK, Corl BA, Geor RJ.Understanding the mechanisms involved in the development of insulin resistance in horses should enable development of effective treatment and prevention strategies. Current knowledge of these mechanisms is based upon research in obese humans and rodents, in which there is evidence that the increased production of pro-inflammatory cytokines by adipose tissue negatively influences insulin signaling in insulin-responsive tissues. In horses, plasma concentrations of the cytokine, tumor necrosis factor-α, have been positively correlated with body fatness and insulin resistance, leading to the hypo...
Gugliandolo E, Crupi R, Biondi V, Licata P, Cuzzocrea S, Passantino A.Although inflammation is an important physiological response, it plays a prominent role in several diseases across the mammalian species. In horses, in particular, inflammation secondary to bacterial infection or translocation is one of the most frequent causes of morbidity and mortality. Research in new molecules with anti-inflammatory and immunomodulatory proprieties and safe use profile is constantly an active field; natural compounds are an important source of molecules with peculiar properties such as antioxidants, anti-inflammatory and immune modulating. Silibinin, a natural polyphenolic...
Vinther AM, Skovgaard K, Heegaard PM, Andersen PH.In horses, insights into the innate immune processes in acute systemic inflammation are limited even though these processes may be highly important for future diagnostic and therapeutic advances in high-mortality disease conditions as the systemic inflammatory response syndrome (SIRS) and sepsis. Therefore, the aim of this study was to investigate the expression of 31 selected blood leukocyte immune genes in an equine model of acute systemic inflammation to identify significantly regulated genes and to describe their expression dynamics during a 24-h experimental period. Systemic inflammation ...
Anderson SL, Singh B.Horses that develop colitis invariably exhibit signs of a systemic inflammatory response syndrome (SIRS). A significant contributor to the development of SIRS in human subjects is delayed neutrophil apoptosis, but this has not been specifically studied in horses. Objective: To determine the occurrence of ex vivo neutrophil apoptosis and its contribution to the development of SIRS in an equine colitis model. Methods: Experiment using a colitis model. Methods: Neutrophils were isolated before and after the induction of colitis using an oligofructose overdose model, placed into culture for 12 h o...
Durando MM, MacKay RJ, Linda S, Skelley LA.Polymyxin B and an antiserum against an Re mutant Salmonella typhimurium were evaluated for protective effect in an equine model endotoxemia. Six 3- to 5-month-old foals were given endotoxin (0.25 micrograms/kg of body weight) IV after no pretreatment, or pretreatment with polymyxin B (6,000 U/kg, IV) or S typhimurium antiserum (1.5 ml/kg, IV). When given without pretreatment, endotoxin caused transient recumbency and increases in rectal temperature, and heart and respiratory rates. In addition, leukopenia and increases in circulating tumor necrosis factor (TNF) and interleukin 6 (IL-6) activi...
Leise BS, Yin C, Pettigrew A, Belknap JK.Further knowledge of equine keratinocyte physiology and keratinocyte response to various stimuli is important in developing a better understanding of disease states involving the epidermis. Objective: To assess the inflammatory cytokine response of cultured equine keratinocytes to various pathogen-associated molecular pattern molecules (PAMPs) from both Gram-negative and positive bacteria likely to be present in equine sepsis. Methods: Keratinocytes were isolated from skin of 2 horses and primary cultures performed. Keratinocytes were harvested for RNA extraction after exposure to lipopolysacc...
Escherichia coli F17 isolated from horse feces was studied in respect to the O antigen (O polysaccharide) structure and genetics. The lipopolysaccharide was isolated by phenol-water extraction of bacterial cells and cleaved by mild acid hydrolysis to yield the O polysaccharide, which was studied by sugar analysis and selective solvolysis with CFCOH along with one- and two-dimensional H and C NMR spectroscopy. The O polysaccharide was found to have a branched pentasaccharide repeat (O-unit) containing one residue each of d-galactose, d-mannose, l-rhamnose, d-glucuronic acid, and N-acetyl-d-gluc...
Morresey PR, Mackay RJ.To measure serum polymyxin B concentration after single and repeated IV infusions in horses. Methods: 5 healthy horses. Methods: In study 1, 1 mg (6,000 U) of polymyxin B/kg was given IV and blood samples were collected for 24 hours. In study 2, 1 mg of polymyxin B/kg was given IV every 8 hours for 5 treatments and blood samples were collected until 24 hours after the last dose. Polymyxin B concentration was measured as the ability to suppress nitrite production by murine macrophages stimulated with lipopolysaccharide and interferon-alpha. Urine was collected prior to the first drug infusion a...
Mendoza Garcia FJ, Gonzalez-De Cara C, Aguilera-Aguilera R, Buzon-Cuevas A, Perez-Ecija A.Little information is available about endotoxemia in donkeys. Characterizing the systemic inflammatory response (SIRS) to lipopolysaccharide (LPS) in donkeys would provide valuable clinical and therapeutic information. The effects of meloxicam on endotoxemia have not been studied in this species. Objective: To study the pathophysiology and gene expression associated with experimentally induced endotoxemia, and evaluate the effects of meloxicam on experimentally induced endotoxemia in donkeys and in equine monocyte cultures. Methods: Six healthy adult female donkeys. Methods: Endotoxemia was in...
Sun WC, Moore JN, Hurley DJ, Vandenplas ML, Murray TF.To assess the anti-inflammatory effects of an adenosine analogue on lipopolysaccharide (LPS)-stimulated equine neutrophils. Methods: Neutrophils obtained from 10 healthy horses. Methods: An adenosine analogue (5'-N-ethylcarboxamidoadenosine [NECA]) was tested for its ability to inhibit production of reactive oxygen species (ROS) in LPS-stimulated equine neutrophils. Selective adenosine receptor antagonists were used to identify the receptor subtype responsible for effects. To assess the mechanism of action of NECA, cAMP concentrations were measured, and effects of dibutyryl cAMP (a stable anal...
Palmer JL, Bertone AL, Malemud CJ, Mansour J.The effects of inflammation on the biochemical and biomechanical properties of articular cartilage at two sites (dorsal and palmar) from the radial facet of the equine third carpal bone were examined in response to a synovitis induced with Escherichia coli lipopolysaccharide (LPS). Four groups were studied. In group 1 synovitis was induced at time zero and evaluated at week 6. Group 2 was the sham-treated control for group 1. In group 3 synovitis was induced at time zero and evaluated at week 2. Group 4 was the sham-treated control for group 3. There was a significant increase (P palmar). The...
Patan-Zugaj B, Gauff FC, Licka TF.To examine the effect of endotoxins on metabolism and histopathologic changes of isolated perfused equine forelimbs. Methods: Forelimbs (comprising the metacarpus and digit) were collected from cadavers of 12 healthy adult horses after slaughter at an abattoir (14 limbs; 1 forelimb of 10 horses and both forelimbs of 2 horses). Methods: Forelimbs were perfused for 10 hours with autologous blood, with and without the addition of endotoxin (80 ng of lipopolysaccharide [LPS]/L). Two limbs of the endotoxin exposure group and 2 nonperfused limbs were loaded to failure of the suspensory apparatus of ...
Leatherwood JL, Gehl KL, Coverdale JA, Arnold CE, Dabareiner RA, Walter KN, Lamprecht ED.Fourteen yearling Quarter horses (351 to 470 kg) were utilized in a randomized complete block design to evaluate potential of glucosamine hydrochloride (HCl) to mitigate intra-articular inflammation following a single inflammatory insult. Horses were blocked by BW, age, and sex, and randomly assigned to treatments for a 98-d experiment. Treatments consisted of a control diet (CON; = 7) fed 1% BW per d (as-fed) of concentrate only or a treatment diet ( = 7) of concentrate top dressed with 30 mg/kg BW glucosamine HCl (99.6% purity; GLU30) offered at 12 h intervals. Horses were maintained in indi...
Bauquier J, Tudor E, Bailey S.Doramapimod, a p38 MAPK inhibitor, is a potent anti-inflammatory drug that decreases inflammatory cytokine production in equine whole blood in vitro. It may have benefits for treating systemic inflammation in horses. Objective: To determine whether doramapimod is well tolerated when administered IV to horses, and whether it has anti-inflammatory effects in horses in a low-dose endotoxemia model. Methods: Six Standardbred horses. Methods: Tolerability study, followed by a blinded, randomized, placebo-controlled cross-over study. Horses were given doramapimod, and clinical and clinicopathologica...
Menzies-Gow NJ, Bailey SR, Katz LM, Marr CM, Elliott J.Lipopolysaccharide (LPS) infusion reduces digital perfusion, but the mediators responsible remain undetermined. Objective: To identify vasoconstrictor mediators released following LPS infusion and relate their appearance in plasma to digital blood flow alterations. Methods: Blood flow in the lateral digital vessels of 6 Thoroughbred horses, following a 30 min infusion of LPS (E. coli 055:B5; 30 ng/kg), was measured using Doppler ultrasonography. Concomitant measurements of hoof wall and coronary band surface temperatures (HWST and CBST) were made. Serial blood samples were collected and plasma...
Wearn JG, Suagee JK, Crisman MV, Corl BA, Hulver MW, Hodgson DR, Geor RJ, McCutcheon LJ.Equine metabolic syndrome (EMS) is a condition of obese horses characterized by insulin resistance, systemic inflammation, and an increased risk of laminitis. The pathogenesis of EMS is thought, in part, to be due to inflammatory proteins produced by adipose tissue. Reducing inflammation may decrease the incidence of laminitis in horses with EMS. Pioglitazone hydrochloride, a thiazolidinedione, has efficacy to reduce obesity associated inflammation in humans. Eight normal, adult, horses were administered 1mg/kg pioglitazone for 14 days, and eight horses served as controls. Physical examination...
Simonen-Jokinen T, Pirie RS, McGorum B, Maisi P.Airway matrix metalloproteinases (MMPs) increase after endotoxin (LPS) exposure, but there are no reports describing dose-dependent increases or activation following exposure. Objective: To study matrix metalloproteinase-9 (MMP-9) and -2 (MMP-2) responses in bronchoalveolar lavage fluid (BALF) from heaves-susceptible and control horses following inhalation of hay dust suspension (HDS), LPS and Aspergillus fumigatus extract (AFE). Methods: Heaves-susceptible (n = 7) and control (n = 6) horses received inhalation challenges with 3 different doses of HDS and LPS. Heaves-susceptible horses (n = 6)...
Morton AJ, Campbell NB, Gayle JM, Redding WR, Blikslager AT.Synovitis in horses is frequently treated by administration of non-steroidal anti-inflammatory drugs (NSAIDs), which inhibit cyclooxygenase isoforms (COX-1 and COX-2). Constitutively expressed COX-1 is involved in physiologic functions such as maintenance of gastric mucosal integrity, whereas COX-2 is up-regulated at sites of inflammation. Thus, COX-2 inhibitors reduce inflammation with reduced gastrointestinal side effects as compared to non-selective COX inhibitors. The objective of the present study was to compare the anti-inflammatory effects of the preferential COX-2 inhibitor etodolac wi...
Moore JN, Norton N, Barton MH, Hurley DJ, Reber AJ, Donovan DC, Vandenplas ML, Parker TS, Levine DM.Endotoxaemia currently is associated with a poor prognosis in horses. The results of recent trials in other species indicate that phospholipid emulsions reduce the deleterious effects of endotoxin (LPS). However, in a previous study in horses, a 2 h infusion of emulsion caused an unacceptable degree of haemolysis. Objective: Rapid administration of a lower total dose of emulsion would reduce the effects of LPS and induce less haemolysis; the emulsion would reduce inflammatory effects of LPS in vitro. Methods: Twelve healthy horses received an i.v. infusion either of saline or a phospholipid em...
