Fibrosis in horses refers to the formation of excess fibrous connective tissue as a reparative or reactive process following injury or inflammation. This condition can affect various organs and tissues, including the lungs, liver, and skin, leading to impaired function and structural changes. Fibrosis is characterized by the excessive deposition of extracellular matrix components, such as collagen, which can result in tissue stiffness and scarring. In equine medicine, fibrosis can be associated with chronic conditions such as equine asthma or hepatic disease. This page compiles peer-reviewed research studies and scholarly articles that investigate the mechanisms, diagnosis, and management of fibrosis in horses, offering insights into its impact on equine health and potential therapeutic approaches.
Södersten F, Hultenby K, Heinegård D, Johnston C, Ekman S.This is a descriptive study of tendon pathology with different structural appearances of repair tissue correlated to immunolocalization of cartilage oligomeric matrix protein (COMP) and type I and III collagens and expression of COMP mRNA. The material consists of nine tendons from seven horses (5-25 years old; mean age of 10 years) with clinical tendinopathy and three normal tendons from horses (3, 3, and 13 years old) euthanized for non-orthopedic reasons. The injured tendons displayed different repair-tissue appearances with organized and disorganized fibroblastic regions as well as areas o...
Back H, Kendall A, Grandón R, Ullman K, Treiberg-Berndtsson L, Ståhl K, Pringle J.A standardbred gelding with a history of 10 days pyrexia and lethargy was referred to the Equine Hospital at the Swedish University of Agricultural Sciences in Uppsala, Sweden.The horse had tachypnea with increased respiratory effort and was in thin body condition. Laboratory findings included leukocytosis, hyperfibrinogenemia and hypoxemia. Thoracic radiographs showed signs of pneumonia with a multifocal nodular pattern, which in combination with lung biopsy findings indicated Equine Multinodular Pulmonary Fibrosis (EMPF). EMPF is a recently described disease in adult horses with clinical s...
Ankringa N, Wijnberg ID, Boerma S, Ijzer J.A 6-year-old Friesian stallion was examined because of signs of exercise intolerance, stiff gait and symmetrical hind weakness, and increased serum liver enzymes. On presentation, the horse showed muscle atrophy of the hindquarters. Neurological investigation showed no abnormalities. Laboratory findings revealed a prolonged prothrombin time and increased levels of alkaline phosphatase (AF), aspartate aminotransferase (ASAT), gamma-glutamyl-transferase (GGT), lactate dehydrogenase (LDH), and bile acids. Histological evaluation of the liver revealed severe cirrhosis and intracytoplasmic greyish ...
Maciel FB, DeRossi R, Módolo TJ, Pagliosa RC, Leal CR, Delben AA.Deep second-degree burns (DSDb) involve all epidermis layers, including the basal laminae. In general, DSDb heals with extensive areas of scarring. Platelet-rich plasma (PRP) is a source of growth factors, obtained by centrifugation and addition of thrombin and calcium, resulting in a gel. The objective of this study was to monitor the healing of DSDb by sequential biopsies after PRP treatment and evaluating by a scanning electron microscopy. Also, characterize bacterial profile and PRP antibacterial effect in horses' burns. Four horses were placed into two groups, G1 and G2, with the groups r...
Szóstek AZ, Siemieniuch MJ, Lukasik K, Galvão AM, Ferreira-Dias GM, Skarzynski DJ.Accurate regulation of the reproductive cycle and successful implantation depend on proper functioning of the endometrium. The aim of this study was to determine whether mRNA transcription of specific enzymes responsible for prostaglandin (PG) synthesis (prostaglandin-endoperoxide synthase, PTGS-2; prostaglandin F(2α) synthase, PGFS; and prostaglandin E(2) synthases, PGES) and PG concentrations in endometrial extracts would change in moderate (Kenney's Category II) and severe phases of fibrosis (Kenney's Category III; endometrosis), compared with healthy endometrium (Kenney's Category I), dur...
Durgam SS, Stewart AA, Pondenis HC, Yates AC, Evans RB, Stewart MC.To compare in vitro expansion of equine tendon- and bone marrow-derived cells with fibroblast growth factor-2 (FGF-2) supplementation and sequential matrix synthesis with pulverized tendon and insulin-like growth factor-I (IGF-I). Methods: Cells from 6 young adult horses. Methods: Progenitor cells were expanded in monolayers with FGF-2, followed by culture with autogenous acellular pulverized tendon and IGF-I for 7 days. Initial cell isolation and subsequent monolayer proliferation were assessed. In pulverized tendon cultures, cell viability and expression of collagen types I and III and carti...
Evans PM, Armour MD, Dubielzig RR.  To describe the gross and histopathological ocular findings in a horse following suspected lightning injury. Methods:   The eyes of a 2-year-old thoroughbred gelding were clinically and histopathologically evaluated following a severe lightning storm following euthanasia because of visual impairment. Results:   Severe corneal edema and hydrops were noted clinically oculus dexter. Indirect ophthalmoscopy revealed bilateral symmetrical raised hyporeflective peripapillary geographic lesions. Histopathologic evaluation revealed corneal edema in the right eye with normal corneal endothelium...
Caniglia CJ, Schramme MC, Smith RK.Collagen fibril size is decreased in repair tissue following tendon injury compared to normal tendon matrix in horses. Mesenchymal stem cells have been suggested to promote regeneration of tendon matrix rather than fibrotic repair following injury, although this concept remains unproven. Objective: To explore the hypothesis that implantation of autologous mesenchymal stem cells derived from bone marrow into a surgically created central core defect in the superficial digital flexor tendon (SDFT) of horses would induce the formation of a matrix with greater ultrastructural similarities to tendon...
Kihara R, Kasashima Y, Arai K, Miyamoto Y.Injury initiates a repair process characterized by influx of fibroblasts and the rapid formation of fibrous scar tissue and subsequent tissue contraction. The response to injury and behavior of the different tendon fibroblast populations, however, has been poorly characterized. We hypothesized that the fibroblasts recovered from tendon with acute injury would exhibit different cell properties relating to adhesion, migration and tensegrity. To test this hypothesis we evaluated the ability of fibroblasts recovered from normal and injured equine superficial digital flexor tendons (SDFTs). The inj...
Alves AG, Stewart AA, Dudhia J, Kasashima Y, Goodship AE, Smith RK.Tendon and ligament injuries have proved difficult to treat effectively. Cell-based therapies offer the potential to harness the complex protein synthetic machinery of the cell to induce a regenerative response rather than fibrous scarring. This article reviews the current state of play with respect to the clinically used cell preparations for the treatment of tendon and ligaments overstrain injuries.
Derksen F, Williams K, Stack A.While airway endoscopy and bronchoalveolar lavage are the methodsof choice for diagnosing exercise-induced pulmonary hemorrhage (EIPH), these techniques do not allow accurate evaluation of the severity of bleeding. EIPH pathology is characterized by occlusive remodeling of pulmonary veins. Affected veins have large collagen deposits in their walls, which reduces their lumens. In the caudodorsal regions, pulmonary vein wall remodeling is associated with hemosiderin accumulation, bronchial circulation angiogenesis, and fibrosis of the alveolar interstitium, bronchovascular bundle, septa, and ple...
Martins TB, Kommers GD, Trost ME, Inkelmann MA, Fighera RA, Schild AL.Twenty-one cases of pythiosis in horses (n = 10), dogs (n = 9) and cattle (n = 2) were investigated. The aetiology in all cases was confirmed by immunohistochemistry. Data related to the clinical course and outcome and localization of the lesions were obtained from pathology reports. The equine lesions consisted of fibrotic tissue with multiple, often coalescing, areas of immature granulation tissue encircling eosinophilic cores. Affected dogs had gastrointestinal and/or cutaneous lesions with either or both of a granulomatous/pyogranulomatous or necrotizing eosinophilic inflammatory reaction....
Carlson KL, Chaffin MK, Corapi WV, Snowden KF, Schmitz DG.The starry sky hepatic pattern is an unusual ultrasonographic appearance of equine liver characterized by numerous small, hyperechoic foci, some of which cast an acoustic shadow, distributed randomly throughout the hepatic parenchyma. Our objectives were to describe the signalment, clinical signs, clinicopathological findings, primary disease process, and ultrasonographic findings of horses with this ultrasonographic pattern, as well as determine the associated gross and histologic changes. The starry sky pattern was identified in 18 adult horses of mixed gender and breed. The horses had vario...
Williams KJ, Derksen FJ, Defeijter-Rupp HL, Robinson NE.Exercise-induced pulmonary haemorrhage (EIPH) occurs in nearly all strenuously exercising horses. Recent studies have attempted to identify the role of free blood within the airspaces, in the lung fibrosis that develops within the lungs of EIPH horses. Objective: Repeated exposure of the equine lung to autologous blood results in lung fibrosis similar to that observed in spontaneous EIPH. Methods: Forty ml of autologous blood from the jugular vein was instilled into preselected lung regions of 6 horses one, 2, 3, 4 or 5 times at 2 week intervals, with 40 ml of saline instilled into the contral...
Watts EJ, Rose MT.Wounds on the limbs of horses are notoriously difficult to heal, with over production of TGFβ1 thought to be responsible for excessive scarring; in contrast, wounds in the oral cavity heal rapidly with minimal scarring. This experiment aimed to determine the effect of TGFβ1 on the production of mRNA and proteins for various extracellular matrix components by two equine fibroblast cell lines isolated from the oral mucosa and distal limb. Fibronectin mRNA was up-regulated by TGFβ1 in the limb but not the oral cells. TGFβ1 increased the ratio of mRNA for collagen types I-III for the oral cell...
Maekawa Y, Sakamoto T, Umezu K, Ohashi N, Harada Y, Yasukochi S, Takigiku K, Takei K, Nakano Y, Inoue N, Otagiri T, Hashida Y.We report a female infant with acute coronary syndrome after Aubert-Imai modification for transposition of the great arteries. Two months postoperatively, she visited the emergency room because of perspiration and tachypnea. She was diagnosed with acute coronary syndrome by blood chemistry examination. Cardiac catheterization revealed Aubert route stenosis, and emergency operation was performed. The lumen around the aortopulmonary window was almost totally occluded by fibrous tissue extending from the equine pericardial patch. This fibrous tissue was completely resected and the aortopulmonary ...
Yuan Z, Gault EA, Campo MS, Nasir L.Equine sarcoids represent the most common skin tumours in equids worldwide, characterized by localized invasion, rare regression and high recurrence following surgical intervention. Bovine papillomavirus type 1 (BPV-1) and less commonly BPV-2 are now widely recognized as the causative agents of the disease. Fibroblasts isolated from sarcoids are highly invasive. Invasion is associated with a high level of viral gene expression and matrix metalloproteinase upregulation. However, it remains unclear to what extent BPV-1 proteins are involved in the transformation of equine cells. To address this ...
Kisiday JD, Hale BW, Almodovar JL, Lee CM, Kipper MJ, Wayne McIlwraith C, Frisbie DD.Mesenchymal stem cells (MSCs) are present in low density in bone marrow and culture expansion is necessary to obtain sufficient numbers for many proposed therapies. Researchers have characterized MSC growth on tissue culture plastic (TCP), although few studies have explored proliferation on other growth substrates. Using adult equine MSCs, we evaluated proliferation on fibrinogen-rich precipitate (FRP) surfaces created from blood plasma. When seeded at 1 × 10(4) cells/cm(2) and passaged five times over 10 days, MSCs on FRP in medium containing fibroblast growth factor 2 (FGF2) resulted in a â...
Arens AM, Barr B, Puchalski SM, Poppenga R, Kulin RM, Anderson J, Stover SM.California horses incur a bone fragility syndrome manifested by pathologic fractures. This study investigated gross, radiographic, and histologic features of the disorder as well as relationships with silicosis and levels of heavy metals and trace minerals through a postmortem study of 9 affected and 3 unaffected horses. Bones and soft tissues were evaluated grossly and histologically. Bones, lymph nodes, and lung tissue were evaluated radiographically. Tissues were evaluated for silicon levels, intracytoplasmic crystals, heavy metals, and trace minerals. All 9 affected horses had osteoporosis...
Celeste CJ, Deschene K, Riley CB, Theoret CL.Wound repair in horse limbs is often complicated by the development of exuberant granulation tissue (EGT) and excessive scarring while body wounds tend to repair uneventfully. EGT resembles the human keloid. While the events leading to keloid formation are not fully elucidated, tissue hypoxia has been proposed as a major contributing factor. The objective of this study was to investigate tissue oxygen saturation in healing full-thickness wounds created on the horse limb and body, using near-infrared spectroscopy. Spectroscopic reflectance data were collected from both anatomic sites at specifi...
Govaere J, Maes S, Saey V, Blancke W, Hoogewijs M, Deschauwer C, Smits K, Roels K, Vercauteren G, de Kruif A.This paper describes a case of uterine fibrosarcoma in an 18-year-old Warmblood mare. The mare had exhibited bloody fluid accumulation inside the uterus and vaginal haemorrhagic discharge since the previous foaling. The mare was euthanized, and on pathological examination, in addition to the uterine neoplasia, multiple metastases were found in the lungs, liver and spleen. The histological and immunohistochemical examination determined that the tumour was a fibrosarcoma. To our knowledge, this is the first paper to describe a uterine fibrosarcoma in a mare.
Ueno T, Nambo Y, Tajima Y, Umemura T.Broad ligament haemorrhage in peripartum mares is a life-threatening disease and there are few reports on the aetiology and pathogenesis of broad ligament haematoma. Objective: To obtain information regarding the sites for the early diagnosis and pathogenesis of broad ligament haematoma of mares. Methods: Thirty-one mares that died of broad ligament haematoma peripartum were examined pathologically for bleeding sites. The arterial distribution of 5 young mares with several parities served as negative controls. Results: Age and/or multiparity were the predisposing factors for the disease. Arter...
Buss DG, Sharma A, Giuliano EA, Mohan RR.Mitomycin C (MMC) is used clinically to treat corneal scarring in human patients. We investigated the safety and efficacy of MMC to treat corneal scarring in horses by examining its effects at the early and late stages of disease using an in vitro model. Methods: An in vitro model of equine corneal fibroblast (ECF) developed was used. The ECF or myofibroblast cultures were produced by growing primary ECF in the presence or absence of transforming growth factor beta-1 (TGFbeta1) under serum-free conditions. The MMC dose for the equine cornea was defined with dose-dependent trypan blue exclusion...
Alkabes KC, Hawkins JF, Miller MA, Nauman E, Widmer W, Dunco D, Kras J, Couetil L, Lescun T, Gautam R.To determine the effects of diode laser palatoplasty on the soft palate in horses. Methods: 6 clinically normal horses and 6 euthanized horses from another study. Methods: 6 horses underwent diode laser palatoplasty (treated horses); 3 received low-dose laser treatment (1,209 to 1,224 J), and 3 received high-dose treatment (2,302 to 2,420 J). Six other horses received no treatment (control horses). The upper respiratory tracts of all treated horses were evaluated immediately following surgery (day 0) and on days 2, 7, 14, 21, 30, and 45. Horses were euthanized on day 45, and magnetic resonance...
Kannegieter NJ, Schaaf KL, Lovell DK, Simon CD, Stone BM.We describe a fibrosarcoma in a 12-year-old Quarterhorse x Arabian gelding as a sequela to equine influenza vaccination. Shortly after the second vaccination, swelling at the site was noticed by the owner and it continued to increase in size over the following 6 months. Biopsy of the mass indicated a fibrosarcoma had developed at the vaccination site. It was approximately 20 cm in diameter and elevated well above the level of the skin. There was no clinical evidence of metastases to the lungs or local lymph nodes. Surgical resection of the mass was performed and the wound healed by first and s...
Dubuc V, Lepault E, Theoret CL.Wound repair in horse limbs is often complicated by excessive fibroplasia and scarring. Occlusion of the microvessels populating the granulation tissue appears to be involved in the excessive accumulation of extracellular matrix during the repair of limb wounds. This study aimed to determine whether endothelial cell hypertrophy or hyperplasia, or both, contribute to microvascular occlusion and whether the pericyte is involved in this anomaly. We created 5 wounds, each 2.5 x 2.5 cm, on both forelimbs and on the body of 6 horses. One limb was bandaged to stimulate excessive wound fibroplasia. We...
Williams IF, Heaton A, McCullagh KG.The connective tissue composition and organisation of the "equine sarcoid" was compared with that of normal adult equine skin to determine whether the cells which produce their respective connective tissue matrices show similar biosynthetic characteristics. No major qualitative difference could be found between the collagen compositions of skin and sarcoid material, although the organisation into fibres of Type III collagen in the sarcoid was markedly greater than that of skin.
Fukuda T, Kikuchi M, Kurotaki T, Oyamada T, Yoshikawa H, Yoshikawa T.Atrophy of seminiferous tubules and interstitial fibrosis are frequently observed in aged horses. Samples from 8 male Thoroughbreds, age 4-24 years, were subjected to histological, electron microscopical and immunohistochemical examination and statistical analysis. There were statistically significant increases in collagen fibres in the lamina propria of seminiferous tubules and testicular interstitium in 3 horses age 23 and 24 years compared with 5 horses age 4-20 years (P<0.001). Lamina propria surrounding atrophic tubules was thickened by an increase in collagen type IV and elastic fibre...
Martano M, Altamura G, Power K, Liguori P, Restucci B, Borzacchiello G, Maiolino P.It is well known that δ-bovine papillomaviruses (BPV-1, BPV-2 and BPV-13) are one of the major causative agents of equine sarcoids, the most common equine skin tumors. Different viruses, including papillomaviruses, evolved ingenious strategies to modulate autophagy, a complex process involved in degradation and recycling of old and damaged material. Methods: The aim of this study was to evaluate, by immunohistochemistry (IHC) and Western blot (WB) analysis, the expression of the main related autophagy proteins (Beclin 1, protein light chain 3 (LC3) and P62), in 35 BPV1/2 positive equine sarco...
Sysel AM, Pleasant RS, Jacobson JD, Moll HD, Warnick LD, Sponenberg DP, Eyre P.The purpose of this study was to determine the systemic and local effects associated with long-term epidural catheterization and epidural morphine-detomidine administration in horses. Methods: Development of systemic or local effects was assessed by placing caudal epidural catheters in study horses and administering injections through the catheters every 12 hours for 14 days. Methods: Ten horses with epidural catheters that received daily injections; six uncatheterized horses presented for euthanasia. Methods: Horses received either 0.2 mg/kg morphine sulfate and 30 micrograms/kg detomidine hy...
Amaral A, Fernandes C, Szóstek-Mioduchowska A, Rebordão MR, Skarzynski DJ, Ferreira-Dias G.Endometrosis is a reproductive pathology that is responsible for mare infertility. Our recent studies have focused on the involvement of neutrophil extracellular traps enzymes, such as elastase (ELA), in the development of equine endometrosis. Noscapine (NOSC) is an alkaloid derived from poppy opium with anticough, antistroke, anticancer, and antifibrotic properties. The present work investigates the putative inhibitory in vitro effect of NOSC on collagen type I alpha 2 chain () mRNA and COL1 protein relative abundance induced by ELA in endometrial explants of mares in the follicular or mid-lu...
Leishman D, Miller RB, Doig PA.The density of uterine glands, height of surface epithelium, numbers of hemosiderin laden macrophages, inflammatory cells and layers of periglandular fibrosis were evaluated in uterine biopsies from 40 mares. These features were found to be highly variable in normal equine endometrium. Minor pathological changes appeared to be masked by this normal variability. Atrophy of uterine glands was recognized in mares which had been barren for more than three years. No significant differences were found between barren and normal mares in the height of epithelium, number of hemosiderin laden macrophage...
Waitt LH, Cebra CK, Tornquist SJ, Löhr CV.A 22-year-old pinto mixed breed mare was admitted for evaluation of severe colic signs and gastric reflux. Multiple nonpainful, variably sized hard masses were palpated in the subcutis over the thorax, abdomen, and hindquarters of the horse. The mare was diagnosed with sterile peritonitis and had systemically high gamma-glutamyltransferase, amylase, and lipase. Three days into treatment she became febrile with signs of persistent and mild abdominal discomfort; euthanasia was elected. Necropsy revealed peripancreatitis, pancreatic fibrosis, abdominal steatitis and panniculitis. Panniculitis ass...
Franke J, Abraham G.Altered airway cell proliferation plays an important role in the pathogenesis of human bronchial asthma and chronic obstructive pulmonary disease (COPD) as well as the equine recurrent airway obstruction (RAO) with consistent changes, i.e. narrowing the airway wall, explained by proliferation and differentiation of fibroblasts. In permanent cell lines, it has been suggested that β2-adrenoceptor agonists and glucocorticoids regulate cell proliferation via the β2-adrenoceptor pathway; indeed, no study was carried out in fresh isolated primary equine bronchial fibroblasts (EBF). We characterize...
Miragliotta V, Lefebvre-Lavoie J, Lussier JG, Theoret CL.Wounds on horse limbs can develop exuberant granulation tissue which resembles the human keloid. Clues gained from the study of over-scarring in horses might help control fibro-proliferative disorders. Objective: The aim of the present study was to clone full-length equine ANXA2 cDNA then to study spatio-temporal expression of ANXA2 and MMP1 mRNA and protein, potential contributors to remodeling, during repair of body (normal) and limb (fibro-proliferative) wounds in an established horse wound model. Methods: Cloning of ANXA2 was achieved by screening size-selected cDNA libraries. Expression w...
McKane SA, Slocombe RF.Necropsy studies of horses suffering exercise-induced pulmonary haemorrhage (EIPH) have identified mild inflammatory lesions with evidence of alveolar fibrosis and bronchiolitis. These lesions were thought to be the result of viral infections that predisposed the affected regions of the lung to EIPH. We have shown previously that during erythrophagocytosis in the alveolar space, there is a prolonged period of macrophage influx and activation. This present study used morphometric analysis to quantify the effects of macrophage activity during erythrophagocytosis, on the alveolar cell population ...
Williams KJ, Derksen FJ, Defeijter-Rupp HL, Robinson NE.Exercise-induced pulmonary haemorrhage (EIPH) occurs in nearly all strenuously exercising horses. Recent studies have attempted to identify the role of free blood within the airspaces, in the lung fibrosis that develops within the lungs of EIPH horses. Objective: Repeated exposure of the equine lung to autologous blood results in lung fibrosis similar to that observed in spontaneous EIPH. Methods: Forty ml of autologous blood from the jugular vein was instilled into preselected lung regions of 6 horses one, 2, 3, 4 or 5 times at 2 week intervals, with 40 ml of saline instilled into the contral...
Delvescovo B, Tomlinson J, DeNotta S, Hodge E, Bookbinder L, Mohammed HO, Divers TJ.Serum biochemistry results and presence of fibrosis on liver biopsies are frequently used as prognostic indicators in horses with liver dysfunction. The objective of this retrospective multicenter study was to determine if the magnitude of abnormal liver specific biochemical tests such as bile acids (BA), direct bilirubin and gamma-glutamyltransferase (GGT), or the presence of fibrosis reported on liver biopsies was associated with prognosis in horses with liver dysfunction. Eighty-two horses older than one year, examined at four referral hospitals in the eastern United States, with BA values ...
McElroy A, Klinge PM, Sledge D, Donahue JE, Glabman RA, Rashmir A.The objectives of this study were to describe the anatomy, histology, and ultrastructure of the equine filum terminale (FT) and to describe the FT in hereditary equine regional dermal asthenia (HERDA), a model of human Ehlers-Danlos syndromes (EDS). Those humans suffer from tethered cord syndrome (TCS) caused by an abnormally structured FT wherein its attachment at the base of the vertebral column leads to long-term stretch-induced injury to the spinal cord. The pathophysiology of TCS in EDS is poorly understood, and there is a need for an animal model of the condition. Histopathologic and ult...
Haechler S, Van den Ingh TS, Rogivue C, Ehrensperger F, Welle M.Congenital hepatic fibrosis with autosomal recessive or dominant inheritance has been described in humans, cats, piglets, and dogs. In horses, only two cases of congenital hepatic fibrosis have been previously reported. This retrospective study of records from the Institute for Animal Pathology, University of Berne, identified 30 foals with liver lesions compatible with congenital hepatic fibrosis. Anamnestic data revealed clinical signs of severe liver injury in most affected animals. Pathologic examination showed severely enlarged, firm livers with thin-walled cysts. Histologically, the live...
Slocombe RF, Huntington PJ, Friend SC, Jeffcott LB, Luff AR, Finkelstein DK.Nine horses with clinical signs of Australian Stringhalt were killed and tissues collected for a detailed pathological study. Lesions were limited to peripheral nerves and muscles. The most severely affected nerves were the superficial and deep peroneal, distal tibial, plantar digital, volar and recurrent laryngeal nerve with changes characterised by a selective loss of large diameter myelinated fibres with various degrees of demyelination, fibrosis, Schwann cell proliferation and onion-bulb formation. A routine evaluation of the brain and spinal cord by light microscopy failed to reveal any c...
Cochrane CA, Freeman KL, Knottenbelt DC.Wound healing in equidae is delayed and more complicated than in other species. These complications arise from a condition known as exuberant granulation tissue formation. The lower limb of the horse is frequently slower to heal than other parts of the body and has a particular tendency to produce excess (exuberant) granulation tissue. Sarcoids are tumor-like lesions of the skin which often appear at the site of wounds. This study compared the growth characteristics of the sarcoid and granulation tissue-derived cells with normal dermal fibroblasts grown from primary cell cultures. All three ce...
Edens LM, Taylor DD, Murray MJ, Spurlock GH, Anver MR.A large fibrotic mass originating from the cecal base was discovered upon surgical exploration of the abdomen in a Thoroughbred mare with a history of chronic colic and weight loss. The mass protruded intraluminally resulting in partial obstruction. Surgical excision was not feasible due to the location of the mass and the inability to exteriorize it adequately from the abdominal cavity. The mass was fibrous with a shiny, gelatinous material present throughout the neoplasm. Histologically, large confluent spaces filled with mucopolysaccharides were identified by staining with Alcian blue. The ...
Gajos K, Kozdrowski R, Nowak M, Siemieniuch MJ.Mares that fail to become pregnant after repeated breeding, without showing typical signs of clinical endometritis, should be suspected of subclinical endometritis (SE). Contact with infectious agents results in altered synthesis and secretion of inflammatory mediators, including cytokines and arachidonic acid metabolites, and disturbs endometrial functional balance. To address the hypothesis that SE affects the immune endocrine status of the equine endometrium, spontaneous secretion of prostaglandin E(2) (PGE(2)), prostaglandin F(2α) (PGF(2α)), 6-keto-PGF(1α )(a metabolite of prostacyclin ...
Gunson DE, Halliwell RE, Minor RR.A 2-year-old female horse had large areas of hyperextensible, fragile skin that were interspersed with areas of normal skin. Affected skin tore easily and contained reduced amounts of dermal collagen. Collagen fibers were fragmented and disorganized, and in trichrome-stained sections, many fibers had abnormal red-stained centers. Electron microscopy showed that many collagen fibers had discrete foci of degradation in which the fibrils were fragmented, loosely packed, and widely separated by granular material. Collagen fibril fragments were present in secondary lysosomes in dermal fibroblasts, ...
Hawkins JF, Couetil L, Miller MA.The objective was to evaluate CO2 laser debridement of the cricoarytenoid joint (CAJ) combined with prosthetic laryngoplasty to prevent post-operative loss of arytenoid abduction in seven horses. Horses were assigned to either laser debridement of the left CAJ and laryngoplasty (laser treated, n=5) or control laryngoplasty (sham, n=2), and were evaluated with endoscopic examinations and measurement of right to left angle quotients (RLQ) to assess maintenance of arytenoid abduction. The animals were euthanased at intervals after surgery and larynges were harvested for post-mortem testing, inclu...
Pearson EG, Hedstrom OR, Poppenga RH.Hemochromatosis, an iron storage disease, was diagnosed in 3 horses with hepatic cirrhosis. Each horse had bridging portal fibrosis and abundant iron deposits in the cytoplasm of hepatocytes. Serum concentrations of liver-derived enzymes and total bile acids were high. However, serum iron concentration was not high, and iron binding capacity was only 46% saturated in the 1 horse in which it was measured. However, the concentration of iron in the liver of this horse was 20 times the reference limits. Hemochromatosis is common in mynah birds and human beings. There are several types of this iron...
Lection J, Wagner B, Byron M, Miller A, Rollins A, Chenier T, Cheong SH, Diel de Amorim M.Endometrial biopsy is required to diagnose mares with chronic endometritis and endometrial degenerative fibrosis. An increase in understanding of equine reproductive immunology could be utilised to create less-invasive, time-efficient diagnostic tools especially when evaluating mares for chronic endometritis. Objective: To evaluate inflammatory cytokine and chemokine concentrations in uterine fluid samples collected by low-volume lavage (LVL) as a potential screening diagnostic biomarker for endometritis. Methods: Prospective cross-sectional clinical study. Methods: Forty-six mares underwent a...
Lowe J, Clifford L, Julian A, Koene M.The data presented in this paper are derived from an in vivo study performed to characterize the nature of the synovial integration process of a 2.5% synthetic cross-linked injectable polyacrylamide hydrogel (2.5 iPAAG) injected IA in horses. Methods: 10 healthy horses not suffering from OA or signs of joint disease were administered 50 or 100 mg 2.5 iPAAG in a total of 13 metacarpophalangeal or middle carpal joints. Methods: Injected joints were examined at 0, 14, 42, and/or 90 days postinjection. Parameters investigated included clinical examination, synoviocentesis, gross pathology, histolo...
Smith EJ, Beaumont RE, Dudhia J, Guest DJ.Tissue fibrosis following tendon injury is a major clinical problem due to the increased risk of re-injury and limited treatment options; however, its mechanism remains unclear. Evidence suggests that insufficient resolution of inflammation contributes to fibrotic healing by disrupting tenocyte activity, with the NF-κB pathway being identified as a potential mediator. Equine embryonic stem cell (ESC) derived tenocytes may offer a potential cell-based therapy to improve tendon regeneration, but how they respond to an inflammatory environment is largely unknown. Our findings reveal for the firs...
Nath LC, Saljic A, Buhl R, Elliott A, La Gerche A, Ye C, Schmidt Royal H, Lundgren Virklund K, Agbaedeng TA, Stent A, Franklin S.Approximately 1-2 per 100,000 young athletes die from sudden cardiac death (SCD) and extreme exercise may be associated with myocardial scar and arrhythmias. Racehorses have a high prevalence of atrial fibrillation (AF) and SCD but the presence of myocardial scar and inflammation has not been evaluated. Cardiac tissues from the left (LAA) and right (RAA) atrial appendages, left ventricular anterior (LVAPM) and posterior (LVPPM) papillary muscles, and right side of the interventricular septum (IVS-R) were harvested from racehorses with sudden cardiac death (SCD, n = 16) or other fatal injur...
Beaumont RE, Smith EJ, David C, Paterson YZ, Faull E, Guest DJ.Tendon injuries are a common problem in humans and horses. There is a high re-injury rate in both species due to the poor regeneration of adult tendon and the resulting formation of scar tissue. In contrast, fetal tendon injuries undergo scarless regeneration, but the mechanisms which underpin this are poorly defined. It is also unclear if tendon cells derived from embryonic stem cells (ESCs) would aid tendon regeneration. In this study we determined the responses of adult, fetal and ESC-derived equine tenocytes to a range of cytokines, chemokines and growth factors that are upregulated follow...
Shapter FM, Granados-Soler JL, Stewart AJ, Bertin FR, Allavena R.Crofton weed (Ageratina adenophora) is a global and highly invasive weed, with ingestion causing severe respiratory disease in horses, leading to irreversible and untreatable pulmonary fibrosis and oedema. While reports of equine pneumotoxicity remain common in Australia and New Zealand, equine pneumotoxicity may be underdiagnosed in other countries where Crofton weed is endemic but poorly differentiated. The pathogenesis of Crofton weed toxicity following ingestion has been well described in a number of different animal models, including rodents, rabbits, and goats. However, induced toxicity ...
