Histology in horses involves the microscopic examination of tissues to understand their structure and function. This field of study provides insights into the cellular composition and architecture of equine tissues, aiding in the diagnosis of diseases and the assessment of tissue health. Histological analysis is used to identify pathological changes, such as inflammation, neoplasia, or degenerative conditions, by examining tissue samples obtained through biopsies or necropsies. Common tissues studied in equine histology include skin, muscle, bone, and internal organs. This page compiles peer-reviewed research studies and scholarly articles that explore histological techniques, findings, and their applications in equine veterinary medicine.
Stewart AS, Kopper JJ, McKinney-Aguirre C, Veerasamy B, Sahoo DK, Freund JM, Gonzalez LM.Gastrointestinal disease is a leading cause of death in mature horses. A lack of in vitro modeling has impeded the development of novel therapeutics. The objectives of this study were to develop and further characterize a small intestinal monolayer cell culture derived from equine jejunum including establishing normal measurements of intestinal permeability and restitution. Three-dimensional enteroids, derived from postmortem sampling of equine jejunum, were utilized to develop confluent epithelial monolayers. The presence of differentiated intestinal epithelial cell types and tight junctions ...
Verhaar N, Hammer E, Reineking W, Hewicker-Trautwein M, Geburek F.To compare the practicability and tissue sample quality between different intestinal biopsy techniques. Methods: Experimental, randomized ex vivo study. Methods: Small intestine of nine horses. Methods: Four different biopsy techniques were evaluated in the aboral jejunum and the ileum within 1 h after euthanasia. One segment was used as control (C), and the applied techniques included an 8 mm biopsy punch (BP), transverse wedge resection (TW), longitudinal wedge resection with transverse closure (LW) and a longitudinal sample using Eppendorfer biopsy forceps (EF). Defects were closed using ...
Martínez-Bartolomé I, Masot J, Serres C.Kenney-Doig scale is considered the international standard method for classifying uterine biopsies in mares; however, its objectivity has been questioned by various studies. In the present study, we analysed the degree of agreement between two pathologists when assessing the same set of 201 uterine biopsies, obtaining a slight to moderate level of agreement (κ = .34/κ = .57). Subsequently, we developed a numerical scale based on the evaluation of histological parameters, including inflammation, fibrosis, glandular density and lymphatic lacunae. Partial scores were summed to obtain a ...
Eren G, López-Albors O, Guilabert Segura R, Jordan Montesinos J, Latorre R.The accessory ligament of the deep digital flexor tendon (AL-DDFT) plays a crucial role in the stay apparatus of the horse. This study aimed to investigate the anatomical relationship between the AL-DDFT, the superficial digital flexor tendon (SDFT), and other structures in the metacarpal region. Sixteen distal forelimbs from eight horses, aged 1 to 6 years, were evaluated through macroscopic, microscopic, and morphometric analyses, utilizing detailed dissection, E12 plastinated sections, and histological analysis. During lateral dissection, a connection was observed between the AL-DDFT and th...
Hoey S, Fogarty U, McAllister H, Puggioni A, Cloak B, Richard H, Skelly C, Laverty S.Articular cartilage can be directly imaged using ultrasonography. The fetlock is a common site of osteochondrosis, with the sagittal ridge of the third metacarpal bone most commonly affected. In osteochondrosis, cartilage thickening may be an initial finding. This postmortem study investigated the ability of ultrasonography to accurately measure the dorsodistal articular cartilage of the third metacarpal bone in young horses, compared to computed tomographic arthrography (CTA) and histological measurements. A total of 33 metacarpophalangeal joints from 18 horses between the ages of 12 days and...
Zedda M, Babosova R, Gadau S, Lepore G, Succu S, Farina V.Fractures of long bones in limbs are rare traumatic events in horses. This study investigates whether the incidence and types of fractures can be related to the histomorphometric features of the radius and tibia, which experience different biomechanical stresses and exhibit varying incidences and types of fractures. Clinical observations suggest that, in adults, slightly transverse and comminuted fractures are present in the radius, while the tibia shows a higher frequency of longitudinal and spiral fractures. Microscopic observations reveal no apparent distinctive characteristi...
Medina-Bolívar AL, Faleiros RR, Martínez-Aranzales JR.Limited information is available on gastric diseases in neonatal foals as compared with extensive studies in young, adult, and geriatric horses. Reports on fetuses are scarce. Objective: Assess at necropsy stomachs of horse, donkey and mule fetuses in the third trimester of gestation to characterize lesions present during intrauterine life. Methods: Forty-six fetal stomachs from both sexes (21 horses, 21 donkeys, and 4 mules) in the third trimester of gestation were collected from a processing plant immediately after slaughter. Methods: Measurements of longitudinal and transverse axes, weight ...
Carpenter AL, Townsend KS, Johnson PJ, Kim DY.An 8-y-old National Show Horse mare was presented for evaluation of pneumonia and laminitis. Harsh bronchovesicular sounds were auscultated throughout both lung fields, and the mare had signs of moderately painful laminitis. Thoracic ultrasonography revealed lung consolidation throughout the dorsal aspect of both lungs, and radiography revealed an extensive diffuse-to-patchy bronchointerstitial lung pattern. The mare's clinical condition rapidly deteriorated, and euthanasia was elected. On postmortem examination, the lungs, omentum, spleen, liver, adrenal glands, kidneys, and femur contained 0...
Fugazzola MC, De Ruijter M, Veraa S, Plomp S, van Buul W, Hermsen G, van Weeren R.The objective of this study was to evaluate a non-resorbable implant for the focal repair of chondral defects in eight adult horses with 12-month follow-up. The bi-layered construct composed of a polycarbonate-urethane-urea biomaterial which was printed in 3D fashion onto a bone anchor was implanted into surgically created osteochondral defects into the femoropatellar joints of eight horses. The analysis of post-mortem outcomes were compared to defects treated with microfracture in the same animal on the contralateral femoropatellar jointfemoropatellar joint. The overall macroscopic scoring af...
Posastiuc FP, Rizzoto G, Constantin NT, Nicolae G, Chiers K, Diaconescu AI, Șerban AI, Van Soom A, Codreanu MD.Anti-Müllerian hormone (AMH) has become a pivotal subject in the study of testicular descent, maturation, integrity, and male fertility. Recent studies explored its roles and implications across various domestic species. A prominent approach involved the understanding of the modulation of AMH in reproductive disorders, including cryptorchidism. While substantial findings have been reported in dogs, ruminants, swine, and horses, data on AMH in feline cryptorchidism remains limited. Here, we aimed to bridge this gap by comparing AMH serum levels among cryptorchid, healthy intact, and castrated ...
Centeno LAM, Bastos HBA, Bueno VLC, Trentin JM, Fiorenza M, Panziera W, Winter GHZ, Kretzmann NA, Fiala-Rechsteiner S, Mattos RC, Rubin MIB.Equine endometrosis is a degenerative and predominantly fibrotic condition resulting from progressive and irreversible multifactorial causes that influence the endometrium of mare. Tissue remodeling in the equine endometrium occurs as part of the pathogenesis of endometrosis, a process characterized by a shift in extracellular matrix (ECM) components. The relationship between matrix metalloproteinases and their specific inhibitors is crucial for the remodeling process. Collagen play a significant role in maintaining a healthy uterus and may promote fibrotic processes. The aim of this study was...
Peretti JC, Dos Santos AB, Davi Dos Santos E, Machado TP, Pescador CA, Quillas LJA, Milani VM, Picetti TS, da Motta AC.Lymphoma is the most common tumor of hematopoietic origin in horses. The course of the disease and clinical signs vary greatly, depending on tumor location and extent. The aim of this report is to describe the occurrence of T-cell-rich oral large B-cell lymphoma with marked local infiltration in a 25-year-old Crioula mare. The mare showed an increase in volume on the right side of its face, dyspnea, anorexia, and progressive weight loss. The clinical assessment showed that the lesion was located in the rostral and caudal sinuses and was markedly invasive to adjacent structures. The autopsy rev...
Damone J, Bass L, Gadomski B, Rao S, Frank C, Moorman VJ.The equine digital cushion (DC) has been a poorly understood structure regarding its mechanical properties and composition. The objective of this study was to develop a sampling technique and to compare the biomechanical and histologic properties of DC between lame and non-lame forelimbs. Both forefeet from horses with induced carpal lameness were radiographed prior to humane euthanasia. Radiographs were used to guide sample collection of two, post-mortem, midline DC samples, palmar and dorsal, via an 8mm biopsy punch. Samples were subjected to compressive testing to determine elastic modulus....
Amari M, Rabbogliatti V, Ravasio G, Auletta L, Brioschi FA, Riccaboni P, Dell'Aere S, Roccabianca P.Radiofrequency (RF) relieves chronic pain in humans, but it is unexplored in horses affected by chronic lameness. This study aims to describe the technique and the histological effects of ultrasound (US)-guided radiofrequency ablation (RFA) of palmar digital nerves (PDNs) in horse's fetlock and pastern, . Unassigned: After assessing the US anatomy of lateral and medial PDNs in fetlock and pastern ( = 10 horses; 20 forelimbs), US-guided RFA was performed on these sites in cadaveric forelimbs ( = 10) applying four different settings with increasing invasiveness ( = 40 total treatmen...
Fukuda K, Mita H, Kuroda T, Tamura N, Kuwano A, Sato F, Takahashi T.To clarify the anti-inflammatory effect of platelet lysate (PL) on equine persistent synovitis by using a model of synovitis induced by monoiodoacetic acid (MIA). Methods: Nonseptic synovitis was induced by administering MIA into both antebrachiocarpal joints of 6 clinically healthy horses on day 0. On days 23, 30, and 37, carpal circumference measurement and synovial fluid collection for assays (leucocytes, LDH, tumor necrosis factor-α, and TGF-β1) were performed, after which PL was injected into 1 antebrachiocarpal joint and saline into the contralateral joint. Synovium and synovial fluid ...
Graham-Thiers PM, Bowen LK.Twelve horses weighing 570 ± 35 kg were split into two groups (standard protein, STD, and balanced protein, BAL) to evaluate the effect of balanced vs. unbalanced protein on muscle mass. Groups were fed grass hay and a 12% CP feed (one formulated for balanced protein). Horses were out of work for 14 wk prior and participated in 1 to 2 h of light-to-moderate exercise 5 d/wk for 12 wk. A 4-d total urine and feces collection period was conducted at the start and end of the study. Urine and feces samples were analyzed for nitrogen (N) to calculate N balance. Muscle mass status was evalua...
Verhaar N, Reineking W, Hewicker-Trautwein M, Grages AM, Kästner SBR, Geburek F.To evaluate the use of laser Doppler flowmetry and spectrophotometry (LDFS) for large intestinal viability assessment in horses with naturally occurring large intestinal strangulations. Methods: By use of LDFS, intestinal microperfusion was quantified as tissue oxygen saturation (tSo2), hemoglobin (tHB), and blood flow (tBF) in cases with large colon volvulus and small colon strangulations undergoing colic surgery (n = 17). Intestinal biopsies were taken from the pelvic flexure in all large colon cases and in small colon cases that underwent intraoperative euthanasia. Measurements were compare...
Tan Yi Shean L, Milne EM, Shaw DJ, Maxwell S, Del-Pozo J.Lipofuscin is a complex mixture of highly oxidized, cross-linked macromolecules that accumulates in neurons with age and some neurodegenerative diseases. Equine dysautonomia (ED) is a polyneuropathy that mainly affects autonomic and enteric nervous systems, resulting in alimentary tract dysfunction. Our main aim was to determine whether neuronal lipofuscin increased with increasing duration of ED. We investigated the prevalence of lipofuscin in cranial cervical ganglia of horses with acute (AED), subacute (SED), and chronic ED (CED), young controls (of similar age to ED cases), and aged contro...
Bermukhametov Z, Suleimanova K, Tomaruk O, Baimenov B, Shevchenko P, Batyrbekov A, Mikniene Z, Onur Girişgin A, Rychshanova R.A total of 396 samples were taken from the hearts, oesophagi, and diaphragms of 132 horses slaughtered at slaughterhouses in 2023 for subsequent examination. Methods: The histological method revealed pathomorphological changes in the muscle tissue. The molecular method identified the pathogen species. Results: Histological examination revealed thick-walled cysts with internal septa and numerous bradyzoites, and mononuclear inflammatory cells with pericyst infiltrates. Microcyst samples were amplified by polymerase chain reaction. Molecular genetic analysis allowed for the identification of 18 ...
Korim F, Revajová V, Koľvek F, Bujňák L, Hreus S, Všianský D.The parotid duct has been reported to be the most common site of sialoliths in horses. In this case report, we described the first confirmed case of the equine sialolithiasis in Slovakia. The work was aimed to describe the transcutaneous approach to removing the sialolith, which manifested as a hard painless mass in the area of the maxillary cheek teeth, in a 14-year-old Slovakian warmblood mare. Pathological-anatomical and histological examination after extirpation confirmed the presence of parotid duct ectasia resulting from calculus. The mineral composition of the sialolith was determined w...
Okudaira M, Cresswell EN, Wollman CW, McDonough SP, Engiles JB, Reesink HL.To describe the development and maturation of equine proximal sesamoid bones (PSBs) in fetuses and young horses using radiography, microcomputed (micro)-CT, and histology. Methods: A descriptive study. Forelimb PSBs from 12 equids ranging in age from 105 days of gestation to 540 days postgestation were evaluated. Radiography was used for preliminary assessment of metacarpophalangeal joint and PSB mineralization, and micro-CT imaging was performed to assess mineralized PSBs. Tissue volume, bone volume fraction, height, width, depth, trabecular thickness, and anisotropy were quantified from midp...
Chiara M, Mariaelena C, Alessandro C, Davide B, Lavinia C, Paola MM, Barbara L, Chiara DP, Flagiello F, Pia PM.The advanced-PRF+ (A-PRF+) is a platelet concentrate, showing a higher concentration of growth factors, an increased number of cells and looser structure of the fibrin clot than leukocyte-PRF. A high variability in the size of PRF associated with patients, haematological features and centrifugation protocols was reported. The aims of this study were to evaluate the feasibility of A-PRF+ production in the field and the correlation between haematological parameters, macroscopic and microscopic features in equine A-PRF+. Samples from twenty Standardbred horses (3-7 years) were harvested with gla...
Skedros JG, Dayton MR, Cronin JT, Mears CS, Bloebaum RD, Wang X, Bachus KN.Many bones experience bending, placing one side in net compression and the other in net tension. Because bone mechanical properties are relatively reduced in tension compared with compression, adaptations are needed to reduce fracture risk. Several toughening mechanisms exist in bone, yet little is known of the influences of secondary osteon collagen/lamellar 'morphotypes' and potential interplay with intermolecular collagen cross-links (CCLs) in prevalent/predominant tension- and compression-loaded regions. Paired third metacarpals (MC3s) from 10 adult horses were prepared for mechanical test...
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...
Becker R, Haenssgen K, Precht C, Khoma OZ, Hlushchuk R, Koch C, Kaessmeyer S, de Preux M.Equine trigeminal-mediated headshaking is a painful neuropathic disorder comparable to trigeminal neuralgia in humans. The selective destruction of pain fibers within the trigeminal ganglion, called rhizotomy, is the surgical treatment of choice for idiopathic trigeminal neuralgia refractory to medical treatment in humans. The human trigeminal ganglion is enclosed by a dural recess called the Meckel's or trigeminal cave, in which the ganglion is surrounded by a cerebrospinal fluid (CSF)-filled subarachnoid space. During glycerol rhizotomy, glycerol is percutaneously injected in this CSF-filled...
Cho PW, Park SA, Sledge D, Gruenwald R, Townsend WM.The aim of this report was to provide a clinical description and clinical, ultrasonographic, and histologic images of a foal with microphthalmia and multiple ocular abnormalities. Methods: A 12-h old Friesian-American Paint Horse crossbred filly presented for blindness, microphthalmia and marked ventral strabismus in both eyes. Methods: A complete ophthalmic examination was performed. Ultrasound biomicroscopy and B-mode ultrasonography were performed. The globes were submitted for histopathology. Results: Ultrasound biomicroscopy demonstrated a hyperechoic cornea void of the typical epithelium...
Stedman JM, Lutter JD, Hallman C, Laverty S, Richard H, Santschi EM.High-field MRI of the equine stifle provides high-resolution information about soft tissues that is useful in the diagnosis of stifle lameness. The aim of this prospective anatomic study was to describe the appearance, position, size, and shape of the equine femorotibial ligaments, meniscal ligaments, and menisci using 3 Tesla MRI under extended, extended-loaded, and flexed conditions. Additionally, histologic examination of the collateral and cruciate ligaments (CLs) of a single stifle was performed to compare with MRI images. In extension, mild variations in MRI signal intensity were apparen...
Lindsay-McGee V, Massey C, Li YT, Clark EL, Psifidi A, Piercy RJ.Equine exercise-associated myopathies are prevalent, clinically heterogeneous, generally idiopathic disorders characterised by episodes of myofibre damage that occur in association with exercise. Episodes are intermittent and vary within and between affected horses and across breeds. The aetiopathogenesis is often unclear; there might be multiple causes. Poor phenotypic characterisation hinders genetic and other disease analyses. Objective: The aim of this study was to characterise phenotypic patterns across exercise-associated myopathies in horses. Methods: Historical cross-sectional study, w...
Machado M, Queiroz-Machado CRR, Queiroz F, Gardner DR, Riet-Correa F.A Mimosa pudica var. unijuga-associated toxicity affecting horses occurred in Araguari, Triângulo Mineiro, Southeast Brazil. Affected horses had gradual hair loss of the mane and tail and endocrine dermatosis after grazing for three months during the dry season on a paddock invaded by the plant. The main histological lesions include compact ortho-keratotic hyperkeratosis and numerous flame follicles. Toxicological analysis by HPLC-UV demonstrated 0.8 mg/g of mimosine in the leaves.
Lin ST, Foote AK, Bolas NM, Sargan DR, Murray RC.Information regarding the histopathology of the proximal phalanx (P1) sagittal groove in racehorses is limited. Twenty-nine cadaver limbs from nine Thoroughbred racehorses in racing/race-training underwent histological examination. Histological specimens of the third metacarpal/metatarsal (MC3/MT3) parasagittal grooves and P1 sagittal grooves were graded for histopathological findings in hyaline cartilage (HC), calcified cartilage (CC), and subchondral plate and trabecular bone (SCB/TB) regions. Histopathological grades were compared between (1) fissure and non-fissure locations observed in a ...
Menarim BC, Gillis KH, Oliver A, Ngo Y, Werre SR, Barrett SH, Rodgerson DH, Dahlgren LA.Synovitis is a major component of osteoarthritis and is driven primarily by macrophages. Synovial macrophages are crucial for joint homeostasis (M2-like phenotype), but induce inflammation (M1-like) when regulatory functions become overwhelmed. Macrophage phenotypes in synovium from osteoarthritic and healthy joints are poorly characterized; however, comparative knowledge of their phenotypes during health and disease is paramount for developing targeted treatments. This study compared patterns of macrophage activation in healthy and osteoarthritic equine synovium and correlated histology with ...
Nixon AJ, Rickey E, Butler TJ, Scimeca MS, Moran N, Matthews GL.Autologous chondrocyte implantation (ACI) has improved outcome in long-term studies of joint repair in man. However, ACI requires sutured periosteal flaps to secure the cells, which precludes minimally-invasive implantation, and introduces complications with arthrofibrosis and graft hypertrophy. This study evaluated ACI on a collagen type I/III scaffold (matrix-induced autologous chondrocyte implantation; MACI(®)) in critical sized defects in the equine model. Methods: Chondrocytes were isolated from horses, expanded and seeded onto a collagen I/III membrane (ACI-Maix™) and implanted into o...
Serrano AL, Quiroz-Rothe E, Rivero JL.Twenty-four 4-year-old Andalusian (Spanish breed) stallions were used to examine the plasticity of myosin heavy chain (MHC) phenotype and the metabolic profile in horse skeletal muscle with long-term endurance-exercise training and detraining. Sixteen horses underwent a training programme based on aerobic exercises for 8 months. Afterwards, they were kept in paddocks for 3 months. The remaining eight horses were used as controls. Three gluteus medius muscle biopsy samples were removed at depths of 20, 40 and 60 mm from each horse before (month 0), during (month 3) and after (month 8) training,...
Nautscher N, Bauer A, Steffl M, Amselgruber WM.This study described corneal morphology in different domestic animals using histological and immunohistochemical methods. Specifically, we evaluated the species-specific distribution pattern of cytokeratins (CKs) and aquaporins (AQPs) to assess their contribution to the strength and transparency of the cornea, respectively. Methods: Corneal sections (2 μm thick) were obtained from 28 pigs, 11 cows, two goats, six horses, four dogs, and five cats and stained with hematoxylin-eosin and periodic acid-Schiff (PAS) reaction. Immunohistochemistry was also performed using CK1 to 3 and AQP1 and 5 an...
Locke M.Techniques for staining (silver, osmium, metal sulfides, ink) and microphotography (epi-illumination) of polished bone surfaces have been developed to visualize the three-dimensional structure of the shafts of mammalian long bones. Bone is a two-compartment system with capillaries and some kinds of connective tissue in one compartment separated from fibers of bone collagen, often forming lamellae, in the other. Laminar bone consists of stacks of lamellae separated by vascular spaces containing capillary network sheets. It is deposited at the periosteal and endosteal surfaces. Osteonic bone, we...
Geburek F, Lietzau M, Beineke A, Rohn K, Stadler PM.Autologous blood-derived biologicals, including autologous conditioned serum (ACS), are frequently used to treat tendinopathies in horses despite limited evidence for their efficacy. The purpose of this study was to describe the effect of a single intralesional injection of ACS in naturally occurring tendinopathies of the equine superficial digital flexor tendon (SDFT) on clinical, ultrasonographic, and histological parameters. Methods: Fifteen horses with 17 naturally occurring tendinopathies of forelimb SDFTs were examined clinically and ultrasonographically (day 0). Injured tendons were ran...
Ugryumova N, Jacobs J, Bonesi M, Matcher SJ.To investigate a novel optical method to determine the three dimensional (3-D) structure of articular cartilage collagen non-destructively. Methods: Polarization-sensitive optical coherence tomography was used to determine the apparent optical birefringence of articular cartilage for a number of different illumination directions. A quantitative method based on the theory of light propagation in uniaxial crystalline materials was validated on equine flexor tendon. Qualitative maps of fiber polar and azimuthal orientation at sites on the posterior and anterior segments of the equine third metaca...
Overbeck W, Witte TS, Heuwieser W.The objective of this study was to compare the accuracy of a uterine swab (US), a cytological brush (CB) and an endometrial biopsy (EB) to detect subclinical endometritis in mares. Cytological and bacteriological results of all three techniques were related to histological occurrence of polymorphonuclear neutrophils (PMNs) in the stratum compactum, commonly known as 'best standard'; to diagnose endometritis. Samples were taken from 55 mares of different breeds without clinical signs of endometritis. Samples for US, CB and EB were collected, smeared on a microscopic slide and cultured for bacte...
van Eps AW, Pollitt CC.Experimental induction of equine laminitis with a reliable and clinically relevant model should facilitate understanding of the disease. Successful induction with oligofructose (OF) could link pasture consumption to laminitis. Objective: To determine whether alimentary administration of OF induces laminitis. Methods: Twelve horses were dosed with OF and 6 received a sham (placebo) treatment. Clinical observations were made and blood collected at 4 h intervals over a 48 h study period. Stained sections of the hoof wall lamellae, examined by light microscopy, were graded for laminitis severity. ...
Katila T.This review suggests a classification for uterine diseases of mares. Information is presented on the prevalence of endometritis in the past and at present. The review describes uterine sampling techniques for mares: swabbing, cytobrushing, low volume lavage and biopsy. The performance of culture, cytology and histology and threshold values is discussed. Correlations between different diagnostic methods and fertility are presented, as well as specificities, sensitivities and positive and negative predictive values of the diagnostic methods. The necessity for double-guarded techniques is emphasi...
Olstad K, Ytrehus B, Ekman S, Carlson CS, Dolvik NI.Material available for research into osteochondrosis (OC) in humans tends to represent chronic lesions. Comparative studies of early lesions in young animals are, therefore, important in clarifying the pathogenesis of OC in humans. Recent studies in pigs provide strong evidence that lesions of articular OC are associated with a focal failure in the cartilage canal vascular supply to epiphyseal growth cartilage (articular-epiphyseal cartilage complex excluding the articular cartilage). The purpose of the present study was to examine histological sections from a specific predilection site for ar...
Monteiro SO, Lepage OM, Theoret CL.To evaluate the effect of platelet-rich plasma on wounds on the distal aspect of the forelimb in horses. Methods: 6 mixed-breed 10- to 15-year-old mares. Methods: 3 wounds were created on metacarpal regions in each of 6 horses (n = 36 wounds total). Eighteen wounds were treated with platelet-rich plasma and bandaged, whereas 18 control wounds were similarly bandaged with no prior topical treatment. Decrease in wound surface area and the required number of excisions of exuberant granulation tissue were recorded until complete healing. Tissue specimens were taken from wounds at 1 week for histol...
Zembowicz A, Knoepp SM, Bei T, Stergiopoulos S, Eng C, Mihm MC, Stratakis CA.Pigmented epithelioid melanocytoma (PEM) is a recently described entity comprising most cases previously described as "animal-type melanoma" and epithelioid blue nevus (EBN) occurring in patients with the multiple neoplasia syndrome Carney complex (CNC). Mutations of the protein kinase A regulatory subunit type 1alpha (R1alpha) (coded by the PRKAR1A gene) are found in more than half of CNC patients. In this study, we investigated whether PEM and EBN are related at the molecular level, and whether changes in the PRKAR1A gene status and the expression of the R1alpha protein may be involved in th...
Hooper PT, Ketterer PJ, Hyatt AD, Russell GM.Laboratory examinations of equine morbillivirus included experimental reproductions of the disease caused by the virus by transmission of mixed lung and spleen taken from two field equine cases into two horses and by inoculating tissue culture virus into a further two horses. The most distinctive gross lesions of the diseases that developed in three of the horses was that of pulmonary edema characterized by gelatinous distension of subpleural lymphatics. Histologically, the lesions in the lungs were those of serofibrinous alveolar edema, alveolar macrophages, hemorrhage, thrombosis of capillar...
Watts AE, Nixon AJ, Yeager AE, Mohammed HO.A consistent and clinically relevant model for the induction of core lesions confined to the mid-metacarpal superficial digital flexor tendon (SDFT) has not been previously reported. Injection of bacterial collagenase is commonly used but often results in large, irregular and inconsistent lesions that disrupt the superficial tendon layers and epitenon. Objective: To develop and evaluate a new injection technique for collagenase induction of SDFT injury. Methods: Collagenase gel was injected into a physical columnar defect created by longitudinally placing a curved 16 gauge 8.89 cm needle in ...
Nacarino-Meneses C, Köhler M.The annual cyclicality of cortical bone growth marks (BGMs) allows reconstruction of some important life history traits, such as longevity, growth rate or age at maturity. Little attention has been paid, however, to non-cyclical BGMs, though some record key life history events such as hatching (egg-laying vertebrates), metamorphosis (amphibians), or weaning (suggested for Microcebus and the hedgehog). Here, we investigate the relationship between non-cyclical BGMs and a stressful biological event in mammals: the moment of birth. In the present study, we histologically examine ontogenetic serie...
van Zyl A, Daniel J, Wayne J, McCowan C, Malik R, Jelfs P, Lavender CJ, Fyfe JA.Two horses were diagnosed as having Mycobacterium ulcerans infections. The first was a 21-year-old Quarterhorse-cross mare living in Mallacoota (a coastal town near the border of New South Wales and Victoria, Australia) that presented with lichenification, hair-loss and oedema on a fetlock, which subsequently ulcerated, as well as a non-healing ulcer on the wither. The second horse was a 32 year-old Standardbred gelding from Nicholson, near Bairnsdale, Victoria, that had an ulcerated lesion on its caudal thigh. Histologically, there were characteristic changes seen with M. ulcerans infections ...
Burk J, Berner D, Brehm W, Hillmann A, Horstmeier C, Josten C, Paebst F, Rossi G, Schubert S, Ahrberg AB.Tendon disease has been treated with multipotent mesenchymal stromal cells (MSCs) in the equine large-animal model with promising success. The aim of this study was to gain more insight into the fate and biodistribution of MSCs after local application into tendon lesions by long-term cell tracking in this large-animal model. Superficial digital flexor tendon lesions were induced in all limbs in six horses and injected with 10106 Molday ION Rhodamine B-labeled MSCs suspended in serum or serum alone. Follow-up was performed using low-field magnetic resonance imaging (MRI), flow cytometry, and hi...
Conze P, van Schie HT, van Weeren R, Staszyk C, Conrad S, Skutella T, Hopster K, Rohn K, Stadler P, Geburek F.To investigate whether autologous adipose tissue-derived mesenchymal stem cells (AT-MSCs) treatment of tendon lesions increases neovascularization during tendon healing. Methods: A standardized surgical model was used to create lesions in both front limb superficial digital flexor tendons (SDFTs) of nine horses. Either AT-MSCs or control substance was injected intralesionally 2 weeks post-surgery. Color Doppler ultrasonography of SDFTs was performed at regular intervals. Horses were euthanized 22 weeks post-treatment and SDFTs were harvested for histology. Results: The color Doppler ultrasonog...
Williams IF, McCullagh KG, Goodship AE, Silver IA.The histological and morphological characteristics of the scar tissue formed during healing after traumatic equine tendon injury have been compared with those of scar tissue produced in response to an enzyme-induced pony tendon injury. Several techniques are currently in use in the treatment of equine tendon sprain and this work formed part of a study of their respective efficacy. It was concluded that the enzyme-induced lesion is resolved by a reparative process very similar in its prognosis and extent to that following a naturally occurring tendon sprain. It may therefore justifiably be used...
Olstad K, Ytrehus B, Ekman S, Carlson CS, Dolvik NI.Failure of the cartilage canal blood supply to epiphyseal growth cartilage has been implicated in the pathogenesis of articular osteochondrosis in horses and other animal species. In a previous study of the developmental pattern of the blood supply in the tarsus of foals, early lesions of osteochondrosis were consistently found in regions where the cartilage canal vessels traversed the chondro-osseous junction. The developmental pattern of blood vessels has also been described in the distal femoral epiphysis; however, the group of foals examined in that study did not have lesions of osteochond...
Stover SM, Pool RR, Martin RB, Morgan JP.The dorsal cortex of the equine third metacarpal mid-diaphyseal bone was characterised during growth by the histological and microradiographic examination of specimens from 30 horses ranging in age from 2 months to 8 y. Bone from horses aged less than 6 months was characterised by rapid periosteal apposition of circumferential trabeculae of woven bone that were next connected by radial trabeculae to the parent cortex. Deposition of lamellar bone on the inner trabecular surfaces resulted in rows of primary osteons. Replacement of primary bone occurred only after 4 months of age and preferential...
Ahrberg AB, Horstmeier C, Berner D, Brehm W, Gittel C, Hillmann A, Josten C, Rossi G, Schubert S, Winter K, Burk J.Mesenchymal stromal cells (MSC) have shown promising results in the treatment of tendinopathy in equine medicine, making this therapeutic approach seem favorable for translation to human medicine. Having demonstrated that MSC engraft within the tendon lesions after local injection in an equine model, we hypothesized that they would improve tendon healing superior to serum injection alone. Methods: Quadrilateral tendon lesions were induced in six horses by mechanical tissue disruption combined with collagenase application 3 weeks before treatment. Adipose-derived MSC suspended in serum or seru...
Martin RB, Lau ST, Mathews PV, Gibson VA, Stover SM.We studied birefringence as an indicator of collagen fiber orientation in the diaphysis of the equine third metacarpal bone. We had previously shown that tissue from the lateral cortex of this bone is stronger monotonically, but less fatigue resistant, than tissue from the medial and dorsal regions. To learn whether collagen fiber orientation might play a role in this regional specialization, we tested three hypotheses using the same specimens: (1) collagen fiber orientation is regionally dependent; (2) remodeling changes collagen fiber orientation; (3) longitudinal collagen fibers correlate p...
Schramme M, Hunter S, Campbell N, Blikslager A, Smith R.Tendon injuries are common in all athletic activities in both humans and horses. Research of treatment modalities for this disease has typically been performed on a model of collagenase-induced tendonitis. This model has several disadvantages. Our hypothesis was that a reproducible core lesion could be created surgically in superficial digital flexor tendons (SDFT), which could then be evaluated consistently using ultrasonography. Methods: Four horses free of forelimb lameness were used in this study. Each horse underwent general anaesthesia and a synovial resector was used to create a core le...
Heinrichs M, Baumgärtner W, Capen CC.Adenomas of the pars intermedia from 19 horses and normal pituitary glands from seven horses were evaluated histologically and immunocytochemically for adrenocorticotropic hormone (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH), beta-endorphin (beta-END), proopiomelanocortin (POMC), prolactin, neuron specific enolase, and glial fibrillary acidic protein (GFAP). The 26 horses ranged in age from 7 to 31 years. Histologically, all adenomas had a uniform pattern characterized by cords of large columnar cells forming palisades and pseudoacini separated by a delicate fibrovascular stroma. I...
Mancini IAD, Vindas Bolaños RA, Brommer H, Castilho M, Ribeiro A, van Loon JPAM, Mensinga A, van Rijen MHP, Malda J, van Weeren R.To report on the experiences with the use of commercial and autologous fibrin glue (AFG) and of an alternative method based on a 3D-printed polycaprolactone (PCL) anchor for the fixation of hydrogel-based scaffolds in an equine model for cartilage repair. In a first study, three different hydrogel-based materials were orthotopically implanted in nine horses for 1-4 weeks in 6 mm diameter full-thickness cartilage defects in the medial femoral trochlear ridge and fixated with commercially available fibrin glue (CFG). One defect was filled with CFG only as a control. In a second study, CFG and ...
Spiesz EM, Thorpe CT, Thurner PJ, Screen HRC.Structure-function relationships in tendons are directly influenced by the arrangement of collagen fibres. However, the details of such arrangements in functionally distinct tendons remain obscure. This study demonstrates the use of quantitative polarised light microscopy (qPLM) to identify structural differences in two major tendon compartments at the mesoscale: fascicles and interfascicular matrix (IFM). It contrasts functionally distinct positional and energy storing tendons, and considers changes with age. Of particular note, the technique facilitates the analysis of crimp parameters, in w...
