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.
Identification of vessel degeneration and endometrosis in the equine endometrium, using narrow-band imaging hysteroscopy. In this study, endometrosis and angiosclerosis in mares were studied. Endometrosis is a severe, progressive, and irreversible fibrotic condition that affects the endometrium, whereas angiosclerosis refers to thickening of vessel walls due to degenerative changes leading to reduced elasticity of the walls and lower perfusion. Histologic evaluations were performed on biopsies and compared with vascular features of the endometrial surface obtained via narrow-band imaging (NBI) hysteroscopy. First, it was determined if hysteroscopic evaluation of the endometrium using NBI resulted in a better visu...
Dual infections of equine herpesvirus 1 and equine arteritis virus in equine respiratory mucosa explants. Equine herpesvirus 1 (EHV-1) and equine arteritis virus (EAV) induce respiratory problems and abortion in horses and are considered as two serious threats to equine industry. Both EHV-1 and EAV misuse patrolling leukocytes in the upper respiratory tract to breach the basement membrane (BM) and to migrate to blood vessels. So far, the behavior and impact of a double infection in the respiratory mucosa of a horse are unknown. In the present study, the outcome of double infections with EHV-1 and the low virulent EAV strain 08P187 (superinfection with an interval of 12h or co-infection) were compa...
Endoscopic Evaluation of Angiogenesis in the Large Airways of Horses with Heaves Using Narrow Band Imaging. Heaves is a severe debilitating condition of horses, characterized by lower airway inflammation and permanent structural changes of the bronchial wall. Chronic inflammation promotes the formation of new vessels, a phenomenon known as angiogenesis. Narrow band imaging (NBI) endoscopy is a noninvasive technique that enhances the visualization of submucosal vessels, and commonly is employed for the study of angiogenesis in human patients. Objective: Using NBI, we aimed to determine whether or not the central airways of horses with heaves undergo angiogenesis. Methods: Horses with heaves during ex...
Effects of erythropoietin on systemic hematocrit and oxygen transport in the splenectomized horse. To test the hypotheses that erythropoietin (rhuEPO) treatment increases systemic hematocrit, maximal O2 uptake (VO2max, by elevated perfusive and diffusive O2 conductances) and performance five female horses (4-13 years) received 15 IU/kg rhuEPO (erythropoietin) three times per week for three weeks. These horses had been splenectomized over 1 year previously to avoid confounding effects from the mobilization of splenic red blood cell reserves. Each horse performed three maximal exercise tests (one per month) on an inclined (4°) treadmill to the limit of tolerance; two control trials and one f...
Differences in the vascular tree of the femoral trochlear growth cartilage at osteochondrosis-susceptible sites in foals revealed by SWI 3T MRI. Focal ischemic chondronecrosis of epiphyseal growth cartilage (EGC) during endochondral ossification is believed to be a key early event on the pathway to osteochondrosis (OC) in both animals and humans. The lateral ridge of the equine trochlea is a site where severe osteochondritis dissecans lesions frequently arise and is a model for the study of naturally occurring disease. Non-invasive imaging to investigate EGC vascularity may help elucidate why focal ischemia occurs. 3T MRI susceptibility-weighted imaging (SWI) of femoral trochlea of OC predisposed (n = 10) and control (n = 6) da...
Topography and ultrasonographic identification of the equine pulmonary vein draining pattern. Information on ultrasound examination of equine pulmonary veins is scarce due to a lack of in-depth anatomical information. Each pulmonary vein drains a specific lung lobe region, after which those veins merge into a collecting antrum, before opening into the left atrium through their respective ostia. The aim of this study was, by using anatomical dissection and silicone casting of equine cardiopulmonary sets, to study the venous drainage of both lungs and the position of the ostia and to investigate whether the ostia can be identified and differentiated using ultrasound. Three out of the fou...
Assessing aortic regurgitation severity from 2D, M-mode and pulsed wave Doppler echocardiographic measurements in horses. Aortic regurgitation (AR) in horses can lead to left ventricular (LV) eccentric hypertrophy, ventricular arrhythmia and heart failure. Objective quantification of the severity of regurgitation is difficult. The aim of this study was to evaluate dimensional measurements, systolic time intervals and blood flow velocities, acquired by standard 2D, M-mode and pulsed wave Doppler echocardiography, for quantification of AR. Echocardiography was performed in 32 healthy horses and 35 horses with AR that were subdivided in three groups (mild, moderate or severe AR). From the recorded images LV, left at...
Feasibility and Safety of Contrast-Enhanced Ultrasound in the Distal Limb of Six Horses. Vascular alterations play important roles in many orthopedic diseases such as osteoarthritis, tendonitis, and synovitis in both human and equine athletes. Understanding these alterations could enhance diagnosis, prognosis, and treatment. Contrast-enhanced ultrasound (CEUS) could be a valuable method for evaluation of blood flow and perfusion of these processes in the equine distal limb, however no reports were found describing feasibility or safety of the technique. The goal of this prospective, experimental study was to describe the feasibility and safety of distal limb CEUS in a sample of si...
The effect of isosorbide dinitrate on uterine and ovarian blood flow in cycling and early pregnant mares: A pilot study. Poor uterine perfusion has been proposed as a cause of infertility in mares. The objective of this study was to investigate the effect of isosorbide dinitrate (ISDN), a nitric oxide donor, on uterine and ovarian blood flow resistance during diestrus and early pregnancy in mares. Six Trotter mares, aged 7 to 14 years, were examined daily during the first 11 days of three diestrous periods, and five of those mares were also examined during the first 11 days of two pregnancies. Six mares randomly received a placebo, a low dose (30 mg, ISDN30), or a high dose of ISDN (60 mg, ISDN60) through t...
Regional heterogeneity in the reactivity of equine small pulmonary blood vessels. Regional differences in large equine pulmonary artery reactivity exist. It is not known if this heterogeneity extends into small vessels. The hypothesis that there is regional heterogeneity in small pulmonary artery and vein reactivity to sympathomimetics (phenylephrine and isoproterenol) and a parasympathomimetic (methacholine) was tested using wire myography on small vessels from caudodorsal (CD) and cranioventral (CV) lung of 12 horses [9 mares, 3 geldings, 8.67 ± 0.81 (age ± SE) yr, of various breeds that had never raced]. To study relaxation, vessels were precontracted with U46619 (10(-...
Equine endometrial vascular pattern changes during the estrous cycle examined by Narrow Band Imaging hysteroscopy. The aim of this study was to evaluate the uterine blood supply and endometrial vessel architecture, during the equine estrous cycle. Narrow Band Imaging (NBI) hysteroscopy was used for evaluating changes in the endometrial vasculature during the estrous cycle [six mares, d 0 (representing the day of ovulation), d 6 and 11 in four locations]. In addition, endometrial biopsy samples were used for immunodetection of markers for angiogenesis (Vascular Endothelial Growth Factor A, its receptor 2, as well as angiopoietin-2 and its receptor-tyrosine-kinase Tie2) during the estrous cycle (three mares,...
Relationship between colour flow Doppler sonographic assessment of corpus luteum activity and progesterone concentrations in mares after embryo transfer. Colour-flow Doppler sonography has been described as a means of assessing corpus luteum (CL) function rapidly, because area of luteal blood vessels correlates well with circulating progesterone (P4) concentrations [P4] in oestrous cycling mares. The aim of this study was to assess the relationships between CL size and vascularity, and circulating [P4] during early pregnancy in mares, and to determine whether luteal blood flow was a useful aid for selecting an embryo transfer recipient. Equine embryos (n=48) were recovered 8 days after ovulation and were transferred to available recipient mares...
The neuropathogenic T953 strain of equine herpesvirus-1 inhibits type-I IFN mediated antiviral activity in equine endothelial cells. Equine herpesvirus-1 (EHV-1) infects equine endothelial cells (EECs) lining the small blood vessels in the central nervous system. However, the effect of type I IFN on EHV-1 replication in the EECs is not well studied. Thus, the primary objective of this study was to investigate the effect of type-I IFN on the replication of the neuropathogenic T953 strain of EHV-1 in vitro in EECs. The initial data showed that the EHV-1 was partly resistant to the biological effect of exogenously supplied recombinant equine IFN-α. Subsequent investigation into the mechanism of resistance showed that EHV-1 in...
Effects of Intrauterine Devices in Mares: A Histomorphological and Immunohistochemical Evaluation of the Endometrium. Oestrous suppression by intrauterine devices (IUDs) is caused by prolongation of luteal function, but the biological mechanism is unknown. The aim of the study was to investigate mechanisms which could explain the action of IUDs. Thirty mares were age-matched and either inseminated (AI, n = 15) or fitted with an IUD (IUD, n = 15) and subsequently divided into four groups: AI-P, pregnant (n = 8); AI-N, non-pregnant (n = 7); IUD-P, prolonged luteal phase (n = 7); and IUD-N, normal luteal phase (n = 8). The median ages were 5.5 and 7 years in AI-P and IUD-P groups and 14 and 11 years in AI-N and ...
Testicular Characteristics and the Block to Spermatogenesis in Mature Hinny. Most hinnies (female donkey×male horse) and mules (female horse×male donkey) are sterile with few reports of equine fertile hybrids. The main cause of this sterility is thought to be a meiotic block to spermatogenesis and oogenesis. This study compared the developmental features of the testes and a histological analyses of spermatogenesis in a male hinny with those of a normal, fertile stallion and Jack donkey. Hinny testes showed a thicker tunica albuginea, fewer blood vessels and more connective tissue in the testis parenchyma than those of the stallion and Jack donkey. Although the mean n...
Effects of estradiol on uterine perfusion in anesthetized cyclic mares affected with uterine vascular elastosis. Uterine vascular elastosis in mares is characterized by degeneration of uterine vasculature through thickening of the elastin layers. Factors commonly associated with this degeneration include age, parity, and chronic uterine endometritis. Affected mares have also been shown to exhibit decreases in uterine blood flow and perfusion of the uterus. Due to the increased thickness of the elastin layers, we hypothesize that vasodilatation of the uterine vasculature is also impaired. To test the functionality of these vessels, we evaluated the vasodilatory effects of estradiol on the uterine vascular...
Stimulation of LH, FSH, and luteal blood flow by GnRH during the luteal phase in mares. A study was performed on the effect of a single dose per mare of 0 (n = 9), 100 (n = 8), or 300 (n = 9) of GnRH on Day 10 (Day 0 = ovulation) on concentrations of LH, FSH, and progesterone (P4) and blood flow to the CL ovary. Hormone concentration and blood flow measurements were performed at hours 0 (hour of treatment), 0.25, 0.5, 1, 2, 3, 4, and 6. Blood flow was assessed by spectral Doppler ultrasonography for resistance to blood flow in an ovarian artery before entry into the CL ovary. The percentage of the CL with color Doppler signals of blood flow was estimated from videotapes of real-t...
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...