Topic:Blood Vessels
Blood vessels in horses are integral components of the circulatory system, responsible for the transportation of blood throughout the body. They consist of arteries, veins, and capillaries, each serving distinct functions in maintaining circulatory efficiency. Arteries carry oxygen-rich blood away from the heart to various tissues, while veins return deoxygenated blood back to the heart. Capillaries facilitate the exchange of nutrients, gases, and waste products between blood and tissues. The structure and function of equine blood vessels are subjects of study due to their role in health and disease, including conditions such as laminitis and equine metabolic syndrome. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and pathophysiology of blood vessels in horses.
Discontinuities in the endothelium of epiphyseal cartilage canals and relevance to joint disease in foals. Cartilage canals have been shown to contain discontinuous blood vessels that enable circulating bacteria to bind to cartilage matrix, leading to vascular occlusion and associated pathological changes in pigs and chickens. It is also inconsistently reported that cartilage canals are surrounded by a cellular or acellular wall that may influence whether bacterial binding can occur. It is not known whether equine cartilage canals contain discontinuous endothelium or are surrounded by a wall. This study aimed to examine whether there were discontinuities in the endothelium of cartilage canal vessel...
Venous Valvular Distribution in the Thoracic and Pelvic Limbs of the Horse. Dysfunction of venous valves can lead to hemodynamic disorders causing venous stasis, which would favour the occurrence of equine laminitis. However, very few studies have investigated venous valves in the horse digit. The purpose of this study was to compare valvular density between thoracic and pelvic limbs and to study the relationship between valvular density of veins and their location, diameter and wall thickness. After dissection, valvular density was calculated based on the number of valves counted in the principal veins of 7 thoracic and 7 pelvic limbs from 7 horses. Our results showe...
Real-time characterization of the uterine blood flow in mares before and after artificial insemination. The present experiment was divided into two studies to investigate the effect of age and endometrial degeneration on uterine blood flow of mares throughout the immediate post-breeding period. In study 1, uterine blood flow was characterized in mares (n = 7 mares/group) with minimal, moderate or severe endometrial degenerative changes (GI, GII and GIII, respectively). In study 2, the effect of age was investigated using young (≤ 6 years) and old (≥ 15 years) mares (n = 7 mares/group). Uterine vascular perfusion and mesometrial pulsatility index (PI) were evaluated every hour from H0 (moment...
Infundibula of equine maxillary cheek teeth. Part 1: Development, blood supply and infundibular cementogenesis. There is increasing interest in diseases of infundibula of equine maxillary cheek teeth. Imperfect infundibular cementogenesis has been recognized as an aetiopathological factor for the onset of infundibular necrosis. In this article, infundibular development was examined with particular attention to infundibular blood vessels and cementogenesis. Forty-one deciduous maxillary premolars prior to eruption were investigated using routine histological and immunohistological methods to visualize blood vessels and the enamel organ. Selected specimens were scanned by micro-computed tomography to anal...
Angiographic Variation of the Internal Carotid Artery and its Branches in Horses. To record the angiographic anatomy of the equine internal carotid artery (ICA) using angiography techniques. Methods: In vitro descriptive study. Methods: Equine cadaver specimens (n = 50). Methods: Head and neck specimens from horses of mixed breed, age, sex, and use without a history of guttural pouch disease had carotid and cerebral angiography using conventional (n = 7) and rotational angiography (43). Angiographic findings were verified by arterial latex casts. Results: Variation in ICA anatomy was categorized into 4 groups: (1) the internal carotid and occipital arteries arising ...
Effect of age and endometrial degenerative changes on uterine blood flow during early gestation in mares. The present experiment was divided into three studies to investigate the effect of age and endometrial degeneration on uterine blood flow of mares. In study 1, the influence of semen infusion and conception was evaluated using noninseminated (non-AI), inseminated nonpregnant (AI-NP), and inseminated pregnant (AI-P) mares (n = 7 mares/group). In study 2, the effect of age was investigated using young (≤6 years), adult (from 8 to 12 years), and old (≥15 years) pregnant mares (n = 7 mares/group). In study 3, uterine blood flow was also characterized in pregnant mares (n = 7 mares/group) with ...
Sympathetic innervation of the suprasesamoidean region of the deep digital flexor tendon in the forelimbs of horses. The purpose of this study was to delineate the pattern of sympathetic innervation in the suprasesamoidean region of the deep digital flexor tendon (DDFT) in horses using immunohistochemical staining (IHC) for tyrosine hydroxylase (TH) and alpha-1 adrenergic receptor (α1-AR). Fourteen forelimbs were collected from 10 horses. Longitudinal sections of the suprasesamoidean region of healthy DDFTs were harvested. Most of the sympathetic innervation was found to be in the walls of blood vessels. The tendon tissue proper was sparsely innervated, with a lesser degree of innervation within the dorsal ...
Testicular perfusion after standing laparoscopic peritoneal flap hernioplasty in stallions. Acquired inguinal herniation is a very common condition in stallions, usually leading to unilateral or bilateral castration to prevent future recurrence. Recently, several surgical techniques such as the standing laparoscopic peritoneal flap hernioplasty (SLPFH) have been developed to avoid herniation recurrence and also preserve the breeding activity of high economic value stallions. However, studies on SLPFH lack more comprehensive and systematic data about reproductive-related adverse effects and outcomes. The aim of this study was to evaluate whether SLPFH of the internal inguinal rings pr...
Microangiographic Comparison of the Effects of 3 Loop Pulley and 6 Strand Savage Tenorrhaphy Techniques on Equine Superficial Digital Flexor Tendon. The 6-strand Savage (SSS) tenorrhaphy pattern is biomechanically superior to the commonly employed 3-loop pulley (3LP); however, its effects on intrinsic tendon vasculature remain unknown. The objective of this study was to compare perfusion of intrinsic vasculature of the equine superficial digital flexor tendon (SDFT) after 3LP and SSS tenorrhaphies. We hypothesized that the SSS technique would significantly decrease vascular perfusion compared to the 3LP technique. Methods: Ex vivo, randomized, paired design. Methods: Horses (n = 9) METHODS: Under general anesthesia, 9 pairs of forelimb...
Mechanoreceptors in the Anterior Horn of the Equine Medial Meniscus: an Immunohistochemical Approach. Lameness due to stifle and especially meniscal lesions is frequent in equine species. In humans, mechanoreceptors involved in proprioceptive function are well studied. Given the high incidence of meniscal injuries in horses, and the lack of information concerning them in equine menisci, our objective was to study these corpuscles in six healthy anterior horns of the equine medial meniscus, which is the most common localisation reported for equine meniscal injuries. Immunohistochemical stainings were performed using antibodies against high molecular weight neurofilaments and glial fibrillary ac...
Effects of an anabolic steroid (Durateston) on testicular angiogenesis in peripubertal stallions. The aim of this study was to determine the effect of the anabolic steroid testosterone on the testicular vascularization, angiogenesis and expression of angiogenic factors, and their receptors in testes of peripubertal stallions. Seven peripubertal stallions were treated with Durateston and castrated either 4 (treatment group 1 [TG1]) or 12 weeks (TG2) after the last injection. The castration of seven untreated control stallions (control group [CG]) took place within the same time. In the testicular specimens, volume density (VD), numerical density (ND), and area of vessels were determined mor...
Characterization of endothelial colony-forming cells from peripheral blood samples of adult horses. To isolate and characterize endothelial colony-forming cells (ECFCs; a subtype of endothelial progenitor cells) from peripheral blood samples of horses. Methods: Jugular venous blood samples from 24 adult horses. Methods: Blood samples were cultured in endothelial cell growth medium. Isolated ECFCs were characterized by use of functional assays of fluorescence-labeled acetylated low-density lipoprotein (DiI-Ac-LDL) uptake and vascular tubule formation in vitro. Expression of endothelial (CD34, CD105, vascular endothelial growth factor receptor 2, and von Willebrand factor) and hematopoietic (C...
Effect of autologous adipose tissue-derived mesenchymal stem cells on neovascularization of artificial equine tendon lesions. 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...
Effects of vascular elastosis on uterine blood flow and perfusion in anesthetized mares. In the uterus of the mare, data obtained using transrectal Doppler ultrasonography indicate that uterine blood flow (UBF) is dynamic and changes throughout the estrous cycle. Degenerative lesions in the uterus are associated with subfertility and infertility. Among these lesions, vascular elastosis has been reported in aged, multiparous, and infertile mares. Angiosis of the uterine vasculature could potentially compromise UBF. The objectives of this experiment are to determine levels of UBF and perfusion of reproductively healthy mares and compare them to levels of subfertile/infertile mares a...
Osteochondrosis Can Lead to Formation of Pseudocysts and True Cysts in the Subchondral Bone of Horses. Osteochondrosis arises as a result of focal failure of the blood supply to growth cartilage. The current aim was to examine the pathogenesis of pseudocysts and true cysts in subchondral bone following failure of the blood supply to the articular-epiphyseal cartilage complex in horses. Cases were recruited based on identification of lesions (n = 17) that were considered likely to progress to or to represent pseudocysts or true cysts in epiphyseal bone in histological sections and included 10 horses ranging in age from 48 days to 5 years old. Cases comprised 3 warmbloods, 3 Standardbreds, 1 Quar...
Is uterine blood flow influenced by hCG and mare age? Doppler ultrasonography is a noninvasive technique which enables us to follow the physiologic and physiopathologic changes in blood flow in tissues. It is becoming an essential tool in veterinary medicine, especially in theriogenology. Twenty-seven Arabian mares were grouped by age ('young', 3-10 y, n=15; 'old', 19-23 y, n=12). The uterine arteries of the mares were examined using Doppler ultrasonography when an ovarian follicle ≥35mm was visible (Day -1). After these measurements, human chorionic gonadotropin (hCG; 2500IU) was administered to 14 mares selected randomly. One day later (Day 0...
Use of micro-lightguide spectrophotometry for evaluation of microcirculation in the small and large intestines of horses without gastrointestinal disease. To evaluate the use of a micro-lightguide tissue spectrophotometer for measurement of tissue oxygenation and blood flow in the small and large intestines of horses under anesthesia. Methods: 13 adult horses without gastrointestinal disease. Methods: Horses were anesthetized and placed in dorsal recumbency. Ventral midline laparotomy was performed. Intestinal segments were exteriorized to obtain measurements. Spectrophotometric measurements of tissue oxygenation and regional blood flow of the jejunum and pelvic flexure were obtained under various conditions that were considered to have a potent...
Percutaneous ultrasound-guided arterial angiography for transarterial coil placement in anesthetized and standing horses. To (1) describe ultrasound-guided percutaneous introduction of a transarterial angiographic catheter into the common carotid artery (CCA); (2) investigate the feasibility of using angiography of the carotid arteries in the guttural pouch region and assess transarterial coil (TAC) placement into the internal carotid artery (ICA). Methods: Experimental study. Methods: Healthy Standardbred horses (n = 6), aged 5-8 years. Methods: Six horses had ultrasound-guided percutaneous CCA catheterization and angiography under general anesthesia. Catheterization sites were ultrasonographically evaluated pos...
Peripheral Blood-Derived Mesenchymal Stromal Cells Promote Angiogenesis via Paracrine Stimulation of Vascular Endothelial Growth Factor Secretion in the Equine Model. Mesenchymal stromal cells (MSCs) have received much attention as a potential treatment of ischemic diseases, including ischemic tissue injury and cardiac failure. The beneficial effects of MSCs are thought to be mediated by their ability to provide proangiogenic factors, creating a favorable microenvironment that results in neovascularization and tissue regeneration. To study this in more detail and to explore the potential of the horse as a valuable translational model, the objectives of the present study were to examine the presence of angiogenic stimulating factors in the conditioned medium...
Use of colour and spectral Doppler ultrasonography in stallion andrology. Doppler ultrasonography is an important tool in the andrological evaluation in humans; however, this method is not so extensively used by equine andrologists. Spectral or pulse Doppler is a useful non-invasive method for the early diagnosis of subfertility problems in the male, especially those triggered by vascular disturbance. The identification of any disturbance in the blood flow of the testis is crucial for a correct diagnosis of various testicular and scrotal disorders but also to monitor the therapeutic outcome following treatment. The aim of this review is to provide an update on the c...
Vascular hamartoma in the central nervous system of a foal. Vascular hamartomas are non-neoplastic developmental anomalies of vessels. Cases of cerebral vascular hamartomas have been previously reported in dogs and cats. A 4-week-old Freiberger foal had shown persistent problems with breathing and swallowing since birth, and bilateral laryngeal paralysis was diagnosed. The foal subsequently developed left sided facial nerve paralysis and a secondary corneal ulcer in the left eye. Necropsy revealed a pinkish mass in the obex region of the brain. The mass was further investigated by histology and immunohistochemistry. Histologically, the mass consisted o...
The distribution pattern of Halicephalobus gingivalis in a horse is suggestive of a haematogenous spread of the nematode. The majority of Halicephalobus gingivalis-infections in horses have been fatal and are usually not diagnosed before necropsy. Therefore, knowledge about the nematode and the pathogenesis of infection in horses is limited. This has resulted in an on-going discussion about the port of entry and subsequent dissemination of H. gingivalis within the host. The present case of H. gingivalis-infection in a horse was diagnosed ante mortem. Post mortem findings, the distribution pattern of H. gingivalis nematodes in the brain, a high prevalence of inflammation in close relation to blood vessels, and the...
Isolation of equine endothelial cells and life cell angiogenesis assay. Arterial or venous thromboses are frequent clinical complications with the risk of fatal progression. Recent studies suggest the disruption of angiogenesis in the course of thrombus resolution as the underlying pathomechanism. Very similar to the situation in human patients, equine vessels have been described to be particularly susceptible to thrombosis. In contrast to humans, equine donors are readily available to obtain organs and tissues for isolation of endothelial cells. Objective of this study was to isolate equine endothelial cells and develop an angiogenesis assay from primary cultures...
A comparison of peritoneal fluid values in mares following bilateral laparoscopic ovariectomy using a vessel sealing and dividing device versus placement of two ligating loops. The objective of this study was to determine the effect of bilateral laparoscopic ovariectomy on peritoneal fluid values in mares and compare how this effect was modified by the method of ovarian vessel hemostasis used. Ten mares undergoing standing bilateral laparoscopic ovariectomy were used in a randomized clinical study. During surgery, blood vessels within the mesovarium were either: (1) sealed and transected with a vessel sealing and dividing device (VSDD), or (2) ligated using two loops placed proximal to each ovary and then the mesovarium transected using laparoscopic scissors. The ova...
Evaluation of regional limb perfusion with chloramphenicol using the saphenous or cephalic vein in standing horses. Regional limb perfusion (RLP) significantly decreases morbidity and mortality associated with distal limb injuries in horses. There is an urgent need for finding additional effective antimicrobial drugs for use in RLP. In this study, we tested the pharmacokinetics (PK) of chloramphenicol in RLP. Eight horses participated in the study, which was approved by the University Animal Care and Use Committee. The cephalic and the saphenous veins were used to perfuse the limbs. Synovial samples were collected from the metacarpo/metatarsophalangeal (MCP/MTP) joint. The Friedman Test was applied for asse...
Vasorelaxation responses to insulin in laminar vessel rings from healthy, lean horses. Hyperinsulinemia causes laminitis experimentally and is a risk factor for naturally occurring laminitis. The aim of this study was to investigate the effects of insulin on laminar vascular relaxation and to induce insulin-associated vascular dysfunction in vitro. Relaxation responses of isolated laminar arterial and venous rings to acetylcholine and insulin were evaluated. To alter vascular function in response to insulin, all vessel rings were incubated with insulin or vehicle, submaximally contracted, administered insulin again and relaxation responses recorded. Laminar arteries were also in...
Equine digital veins are more sensitive to superoxide anions than digital arteries. This work was designed to investigate (i) the effect of superoxide dismutase (SOD) inhibition on endothelial function and (ii) the free radical-induced endothelial dysfunction in equine digital veins (EDVs) and equine digital arteries (EDAs) isolated from healthy horses. EDV and EDA rings were suspended in a 5 ml organ bath containing Krebs solution. After a 60 min equilibration period, EDV and EDA rings were contracted with phenylephrine. Then, cumulative concentration-response curves (CCRCs) to acetylcholine were performed. In both EDVs and EDAs, acetylcholine (1 nM to 10 µM) produced conce...
Regional disturbances in blood flow and metabolism in equine limb wound healing with formation of exuberant granulation tissue. As in other fibroproliferative disorders, hypoxia has been suggested to play a key role in the pathogenesis of exuberant granulation tissue (EGT). The purpose of this study was to investigate metabolism and blood flow locally in full-thickness wounds healing with (limb wounds) and without (body wounds) formation of EGT. Microdialysis was used to recover endogenous metabolites from the wounds, and laser Doppler flowmetry was used to measure blood flow. Measurements were performed before wounding and 1-28 days after wounding. Blood flow was consistently lower in limb wounds than in body wounds t...
Comparison of the blood supply to the articular-epiphyseal growth complex in horse vs. pony foals. To increase understanding of why the prevalence of clinical/radiographic osteochondrosis (OC) dissecans is high in horses and low in ponies. Objective: To investigate whether the clinical difference in OC occurrence between horses and ponies could partly be explained by a difference in: 1) number of patent vessels in the epiphyseal growth cartilage; 2) duration of the presence of patent cartilage canals; or 3) growth cartilage thickness at predilection sites for OC. The hypothesis was that pony foals would have fewer cartilage canals, shorter duration of blood supply and thinner growth cartila...