Showing papers in "Veterinary Clinics of North America-equine Practice in 2011"
TL;DR: The concept of an equine metabolic syndrome (EMS) was first proposed in 2002 and was recently described in a consensus statement released by the American College of Veterinary Internal Medicine.
Abstract: The concept of an equine metabolic syndrome (EMS) was first proposed in 2002. This concept has developed over time, and EMS was recently described in a consensus statement released by the American College of Veterinary Internal Medicine. In human medicine, metabolic syndrome (MetS) refers to a set of risk factors that predict the risk of cardiovascular disease, including obesity, glucose intolerance and insulin resistance (IR), dyslipidemia, microalbuminuria, and hypertension. EMS shares some of the features of MetS, including increased adiposity, hyperinsulinemia, IR, but differs in that laminitis is the primary disease of interest.
246 citations
TL;DR: This review focuses on the pathophysiology and clinical syndrome, as well as advances in diagnostic testing and treatment of PPID, with an emphasis on those findings that are new since the excellent comprehensive review by Schott in 2002.
Abstract: Equine pituitary pars intermedia dysfunction (PPID), also known as equine Cushing's syndrome, is a widely recognized disease of aged horses. Over the past two decades, the aged horse population has expanded significantly and in addition, client awareness of PPID has increased. As a result, there has been an increase in both diagnostic testing and treatment of the disease. This review focuses on the pathophysiology and clinical syndrome, as well as advances in diagnostic testing and treatment of PPID, with an emphasis on those findings that are new since the excellent comprehensive review by Schott in 2002.
176 citations
TL;DR: The current understanding of the mechanisms by which MSCs influence repair and regeneration are discussed, with an emphasis on the clinical importance of MSC trophic activities.
Abstract: This article provides an overview of mesenchymal stem cell (MSC) biology. In the first section, the characteristics that are routinely used to define MSCs-adherence, proliferation, multi-lineage potential, and "cluster of differentiation" marker profiles-are discussed. In the second section, the major tissues and body fluids that are used as sources for equine MSCs are presented, along with the comparative biologic activities of MSCs from specific locations. Finally, the current understanding of the mechanisms by which MSCs influence repair and regeneration are discussed, with an emphasis on the clinical importance of MSC trophic activities.
103 citations
TL;DR: The author provides a clinical overview on disorders of calcium and phosphate in the horse and describes their interaction and interdependence with other ions, including potassium and magnesium.
Abstract: Calcium and phosphate have structural and nonstructural functions, and their concentrations in the extracellular compartment are affected by the physiologic status of the animal as well as diseases. Important progress in understanding calcium and phosphorus metabolism in healthy and diseased horses and foals has been made in recent years. For example, several studies have confirmed that hypocalcemia is frequent in horses with gastrointestinal disease and that calcium endocrine dysregulation is associated with survival in foals. One critical point in the homeostasis of these minerals is their interaction and interdependence with other ions, including potassium and magnesium. In this review, the author provides a clinical overview on disorders of calcium and phosphate in the horse.
80 citations
TL;DR: The main goal of this review is to discuss the biology of adult mesenchymal stem cells in the context of immunology.
Abstract: The recent interest in equine stem cell biology and the rapid increase in experimental data highlight the growing attention that this topic has been receiving over the past few years. Within the field of stem cell biology, the relevance of immunobiology is of particular intrigue. It appears that optimal and effective stem cell therapy for equine patients will require a thorough analysis of the immune properties of stem cells as well as their response to immune mediators. The main goal of this review is to discuss the biology of adult mesenchymal stem cells in the context of immunology.
62 citations
TL;DR: The history, experimental and clinical literature, and currently accepted preparation and usage strategies for both platelet-rich plasma and autologous conditioned serum are discussed.
Abstract: Autologous biologic therapies such as platelet-rich plasma and autologous conditioned serum are in widespread clinical use to treat musculoskeletal pathology in horses. These substances exert a therapeutic effect through the provision of either anabolic or anti-catabolic factors, or a combination of both. This article discusses the history, experimental and clinical literature, and currently accepted preparation and usage strategies for both platelet-rich plasma and autologous conditioned serum.
55 citations
TL;DR: Lesions of the neck should be considered if local analgesic techniques of the limbs fail to abolish lameness or if there are clinical signs directly referable to the neck such as pain, abnormal neck posture, stiffness, or patchy sweating.
Abstract: Lesions of the neck are an uncommon primary cause of pain resulting in either lameness or poor performance but should be considered if local analgesic techniques of the limbs fail to abolish lameness or if there are clinical signs directly referable to the neck such as pain, abnormal neck posture, stiffness, or patchy sweating Accurate diagnosis requires careful clinical examination, exclusion of other causes of lameness or poor performance, and accurate interpretation of diagnostic imaging findings
53 citations
TL;DR: A review of the current state of play with respect to clinically used cell preparations for the treatment of tendon and ligaments overstrain injuries can be found in this article, where 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.
Abstract: 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.
48 citations
TL;DR: Thyroid hormone supplementation seems to be well tolerated, even in euthyroid horses, and two syndromes of hypothyroidism are well described in foals.
Abstract: Regulatory control of the thyroid gland in horses is similar to other species. Clinical signs of hypothyroidism in adult horses are minimal. Several drugs and physiologic and pathophysiological states can cause circulating thyroid hormone concentrations to be low without actual pathology of the thyroid gland. Thus, nonthyroidal factors must be ruled out before a diagnosis of hypothyroidism can be made. Thyroid hormone supplementation seems to be well tolerated, even in euthyroid horses. Neonatal foals have very high circulating thyroid hormone concentrations, and deficiencies result in significant clinical signs. Unlike in adults, two syndromes of hypothyroidism are well described in foals.
47 citations
TL;DR: This review discusses the mechanisms, diagnosis, and clinical consequences of adrenocortical insufficiency, with particular focus on the current understanding of RAI/CIRCI in horses and foals.
Abstract: The adrenal cortices produce various steroid hormones that play vital roles in several physiologic processes. Although permanent adrenocortical insufficiency is rare in all species, emerging evidence in both human and equine medicine suggests that transient reversible adrenocortical dysfunction resulting in cortisol insufficiency frequently develops during critical illness. This syndrome is termed relative adrenal insufficiency (RAI) or critical illness-related corticosteroid insufficiency (CIRCI) and can contribute substantially to morbidity and mortality associated with the primary disease. This review discusses the mechanisms, diagnosis, and clinical consequences of adrenocortical insufficiency, with particular focus on the current understanding of RAI/CIRCI in horses and foals.
42 citations
TL;DR: Results from experimental model and human clinical studies are presented along with available data from equine studies on cell-based therapies for treatment of equine joint disease.
Abstract: Joint disease is a major cause of wastage in performance horses. Arthritis can be challenging to treat because articular cartilage has little or no capacity for repair, therapeutic options are limited and are largely targeted at ameliorating clinical signs of joint disease. Cell-based therapies have potential to overcome the intrinsic constraints to articular cartilage repair. This article focuses on cell-based therapies for treatment of equine joint disease. Results from experimental model and human clinical studies are presented along with available data from equine studies.
TL;DR: The association of Mg and endotoxemia, insulin resistance, and brain injury is described and the clinical signs, consequences, and treatment of hypomagnesemia in horses are discussed.
Abstract: Magnesium (Mg) is an essential macroelement that is required for cellular energy-dependent reactions involving adenosine triphosphate and for the regulation of calcium channel function. Subclinical hypomagnesemia is common in critically ill humans and animals and increases the severity of the systemic inflammatory response syndrome; worsens the systemic response to endotoxins; and can lead to ileus, cardiac arrhythmias, refractory hypokalemia, and hypocalcemia. This article discusses the clinical signs, consequences, and treatment of hypomagnesemia in horses and describes the association of Mg and endotoxemia, insulin resistance, and brain injury.
TL;DR: This review provides a summary of current commercially available cell-based therapeutic products for equine applications, their similarities and differences, and current objective data relating to their clinical efficacy.
Abstract: Several cell-based therapeutic options to treat musculoskeletal injuries in horses are commercially available. The current literature supports the use of cell-based therapies to treat equine musculoskeletal injuries. Researchers continue to search for more effective cell-based therapies to provide practitioners with optimal treatment tools for musculoskeletal injuries in horses. Cell-based therapies require specialized facilities and technical competencies that might not be available or economically justifiable in many private practices. This review provides a summary of current commercially available cell-based therapeutic products for equine applications, their similarities and differences, and current objective data relating to their clinical efficacy.
TL;DR: This article reviews the published techniques for collection and propagation of equine MSC, focusing on bone marrow-derived and adipose-derived cells.
Abstract: Mesenchymal stromal cells (MSC) are derived from adult mesenchymal tissues and have the ability to undergo differentiation into bone, cartilage, and fat, and have therefore attracted great interest in regenerative medicine. Many isolation and culture methods have been described, making comparison between laboratories and quality-control protocols difficult. A uniform protocol to characterize equine MSC has recently been proposed, aiming to introduce consistency across the equine stem cell research field. This article reviews the published techniques for collection and propagation of equine MSC, focusing on bone marrow-derived and adipose-derived cells.
TL;DR: The article emphasizes the key role of osteoprogenitor cells in the formation of bone and where the clinical applications of current research may lend themselves to large animal orthopaedics.
Abstract: This article provides an overview of the cellular and molecular events involved in bone repair and the current approaches to using stem cells as an adjunct to this process. The article emphasizes the key role of osteoprogenitor cells in the formation of bone and where the clinical applications of current research may lend themselves to large animal orthopaedics. The processes involved in osteogenic differentiation are presented and strategies for bone formation, including induction by osteogenic factors, bioscaffolds, and gene therapy, are reviewed.
TL;DR: In this paper, the authors present an overview on endocrine responses to critical illness in horses and foals and also some comparative information, showing that most admissions to equine intensive care units are related to horses with gastrointestinal disease and septic foals, most endocrine information during critical disease are generated from these populations.
Abstract: Critical illness challenges many endocrine homeostatic systems to overcome diseases, stress, and hostile conditions that threaten survival. Coordinated and consecutive responses by the autonomic nervous system, endocrine metabolic adaptations to mobilize and conserve energy and electrolytes, cardiovascular adjustments to maintain organ perfusion, and immunomodulation to overcome infections and inflammation are required. Because most admissions to equine intensive care units are related to horses with gastrointestinal disease and septic foals, most endocrine information during critical disease are generated from these populations. This article presents an overview on endocrine responses to critical illness in horses and foals and also some comparative information.
TL;DR: The essential features needed to characterize a cell type as pluripotent, specific challenges in using the horse as a model organism for pluripoline cell generation, and current and upcoming clinical trials using ES/iPS cells are summarized.
Abstract: The field of regenerative medicine research is rapidly expanding for both human and animal model organisms. One area of particular interest to many equine researchers is the possibility of isolating or generating cells that are pluripotent, therefore capable of producing differentiated cell types derived from all three primary germ layers. Currently, several reports of equine embryonic stem-like (ES) cell isolation can be found in the literature. Meanwhile, other groups are working to produce equine induced pluripotent stem (iPS) cells. The focus of this chapter is to provide a background summary of the essential features needed to characterize a cell type as pluripotent in any species, specific challenges in using the horse as a model organism for pluripotent cell generation, and a brief introduction of current and upcoming clinical trials using ES/iPS cells.
TL;DR: Recognition of epistaxis or mucopurulent nasal discharge, together with signs of dysfunction of the cranial nerves in contact with the guttural pouches, are important key points in order to consider a comprehensive evaluation of these structures and further definitive diagnosis.
Abstract: The close relationship between guttural pouches, cranial nerves, and sympathetic structures make neurologic abnormalities due to diseases of the guttural pouches (especially mycosis) possible. Recognition of epistaxis or mucopurulent nasal discharge, together with signs of dysfunction of the cranial nerves in contact with the guttural pouches, are important key points in order to consider a comprehensive evaluation of these structures and further definitive diagnosis. Diseases of the guttural pouches can also cause signs such as dysphagia, abnormal soft palate positioning, laryngeal paralysis, and Horner syndrome due to lesions in one or more of the cranial nerves or sympathetic structures involved with these functions. Therefore, an accurate diagnosis is essential for treatment.
TL;DR: The approaches to producing and identifying the best possible evidence that is necessary for the full acceptance of stem cell therapies in the horse are identified and the approaches that will allow future clinical studies in stem cell therapy to provide the best evidence for determining efficacy are reviewed.
Abstract: Evidence-based medicine (EBM) refers to the conscientious, explicit, and judicious use of current best evidence from research for the care of an individual patient. Central to the adoption of EBM is both producing and identifying the best possible evidence for a particular intervention or therapy. This article identifies and reviews the approaches to producing and identifying the best possible evidence that is necessary for the full acceptance of stem cell therapies in the horse and reviews the approaches that will allow future clinical studies in stem cell therapies to provide the best evidence for determining efficacy.
TL;DR: Understanding the maturation of the endocrine system and the associated energy metabolism in the equine neonate will support appropriate therapeutic interventions as well as prognostic assessment of the sick foal.
Abstract: Hormonal control of energy metabolism plays an important role in the peripartum development and health of the equine neonate. The endocrine system is generally functional at birth, but the maturation of the endocrine system and the associated energy metabolism is delayed and continues during the postnatal period. The energy metabolism is susceptible to disturbances, especially when illness occurs. Hormones involved in energy metabolism have recently been studied in healthy and critically ill neonatal foals. Understanding these hormones in the equine neonate will support appropriate therapeutic interventions as well as prognostic assessment of the sick foal.
TL;DR: The importance of the hypothalamic-pituitary (HP) interactions in mammals is well recognized as discussed by the authors, where activation of both the HP axis and sympathetic nervous systems results in adrenocortical and adrenomedullary secretion of corticosteroids and catecholamines, respectively.
Abstract: The importance of hypothalamic-pituitary (HP) interactions in mammals is well recognized. In health, this highly regulated and integrated system is involved in the homeostasis of intermediary metabolism, immune responses, body temperature, hunger, thirst, growth, reproduction, and cardiovascular function, to name a few functions. The hypothalamus coordinates many hormonal and behavioral circadian rhythms and complex neuroendocrine inputs/outputs and behaviors, including level/content of consciousness, mood, instinctive behaviors (eg, maternal), and feeding. The HP axis is critical for evoking the biologic responses to internal and external stressors, where activation of both the HP axis and sympathetic nervous systems results in adrenocortical and adrenomedullary secretion of corticosteroids and catecholamines, respectively. These biologically active messengers modulate important responses, such as heightened alertness, glucose mobilization/use, vasomotor tone, cardiac output to improve delivery of metabolic fuel (notably glucose and oxygen), and removal of metabolic waste (lactic acid and carbon dioxide) during times of physiologic and pathologic stress. Like many biologic systems, there is a limit and capacity for these responses to work and when they are reached or exceeded, HP axis dysfunction results in serious compromises that can lead to increased morbidity and mortality. Dysfunctions of any of the multiple HP axes can modify many physiologic functions and, if severe, can be life threatening. Individual and species differences exist regarding HP activation, stimulation, hormonal secretion, and effector organ responses. Disorders of the hypothalamic-pituitary-adrenal axis (HPAA) are better described in the human and comparative literature, with a paucity of available information in the horse. In humans, HPAA dysregulation related to sepsis/septic shock, traumatic central diabetes insipidus, and syndrome of inappropriate antidiuretic hormone secretion (SIADH) are examples of diseases that affect one or more components of the HP system. Although the HPAA has been the most studied HP axis in the horse, when compared with other species, available information is lacking.
TL;DR: Issues raised include the characterization and use of tissue- and anatomic location-specific mesenchymal stem cell sources, the putative advantages and feasibility of allogeneic embryonic stem cell and MSC products, the technical advantages and performance of cell-based biologic agents that do not require extensive ex vivo manipulation, and the logistics required to demonstrate cell- based therapy efficacy in horses.
Abstract: This article focuses on current issues facing cell-based therapies in equine practice and future studies validating the use of stem cells and related biologic therapies for the treatment of musculoskeletal conditions in the horse. Issues raised include the characterization and use of tissue- and anatomic location-specific mesenchymal stem cell (MSC) sources, the putative advantages and feasibility of allogeneic embryonic stem cell and MSC products, the technical advantages and performance of cell-based biologic agents that do not require extensive ex vivo manipulation, the regulation of MSC homing, potential nonorthopaedic stem cell applications, and the logistics required to demonstrate cell-based therapy efficacy in horses.
TL;DR: Horses spend most of their day eating, standing, and occasionally exercising, which can range from running in a pasture to athletic training, and under resting conditions, horses easily maintain the internal environment.
Abstract: Horses spend most of their day eating, standing, and occasionally exercising. Exercise can range from running in a pasture to athletic training. Under resting conditions, horses easily maintain the internal environment. The performance of work or exercise is a major physiologic challenge, a disturbance to homeostasis that invokes an integrative response from multiple organ systems. The response to exercise involves endocrine and neuroendocrine signaling associated with the short-term and adaptive control of many systems. The coordinated control of multiple physiologic variables is essential for achieving regulation to maintain the integrity of the internal environment of the body.
TL;DR: Modern imaging techniques provide much useful information in horses with neurologic disease that are important for making a diagnosis, planning treatment, monitoring patient response, or providing prognostic information to guide owner choices regarding decisions about patient care.
Abstract: Neuroimaging underwent a dramatic revolution during the past few decades due to the development of new technologies that produce exquisite images of patient morphology and function, new technologies that store and distribute information more efficiently, and research that has improved understanding of pathogenesis and effective clinical use of new imaging methods. Advanced equine neuroimaging is a specialized field with unique challenges associated with patient size, availability of equipment, using equipment designed for humans, small sample size for various diseases, and issues associated with recovering a horse with neurologic problems from general anesthesia. Despite these challenges, modern imaging techniques provide much useful information in horses with neurologic disease that are important for making a diagnosis, planning treatment, monitoring patient response, or providing prognostic information to guide owner choices regarding decisions about patient care. In particular, CT and MRI have been beneficial in diagnosing several equine neurologic diseases including congenital malformations (eg, hydrocephalus), equine protozoal myeloencephalitis, strangles (Streptococcus equi ssp. equi) abscesses, nigropallidal encephalomalacia, pituitary macroadenomas, cholesterinic granulomas, THO, CSM, trauma, and various neoplasms. Optimizing equine neuroimaging starts with selecting an appropriate examination, understanding the prior probability of disease and the capabilities of the different imaging technologies, understanding normal anatomy and pathogenesis, and having a systematic approach to review the images. Advanced equine neuroimaging will continue to evolve as more of the challenges are overcome and new research is produced on the effective use of imaging methods and understanding of specific diseases.
TL;DR: For example, during equine gestation, ergopeptine alkaloid exposure is not uncommon, and pregnant mares are particularly sensitive to the endocrine disruptive effects of these compounds on lactogenesis and steroidogenesis.
Abstract: During equine gestation, ergopeptine alkaloid exposure is not uncommon, and pregnant mares are particularly sensitive to the endocrine disruptive effects of these compounds on lactogenesis and steroidogenesis. Agalactia, prolonged gestation, abortion, dystocia, and placental and fetal abnormalities are all clinical manifestations of changes in the endocrine milieu induced by the ingestion of ergopeptine alkaloid-contaminated feedstuffs by mares during late gestation. An understanding of the endocrine disruptive effects of gestational exposure to ergopeptine alkaloids is necessary for the diagnosis of potential exposures to these compounds and for effective prophylaxis and therapy.
TL;DR: Electrodiagnostic testing is an area that has the potential to document and improve the understanding of NM disease yet is uncommonly performed.
Abstract: NMD is an important cause of morbidity in horses. Signs of dysfunction could be variable depending on the specific area affected. NM disease can go unrecognized if a thorough evaluation is not performed in diseased horses. Electrodiagnostic testing is an area that has the potential to document and improve our understanding of NM disease yet is uncommonly performed. Keeping an open and observant mind will enhance our ability to search and find answers.
TL;DR: An important and ongoing court battle that focuses on the marketing and promotion of cellular-based therapies for humans that could have a significant impact on the regulation of both human and veterinary products is reviewed.
Abstract: This article provides an overview of the US Food and Drug Administration's current and potential regulation of veterinary regenerative medicine and the various products used in the practice. This article also discusses several of the potential enforcement risks associated with the commercialization of such therapies and products and offers the reader strategies for mitigating those risks. Finally, the article concludes with a review of an important and ongoing court battle that focuses on the marketing and promotion of cellular-based therapies for humans that could have a significant impact on the regulation of both human and veterinary products.
TL;DR: Familiarity with disorders that can result in recumbency will facilitate more rapid diagnosis and more appropriate formulation of a prognosis.
Abstract: Evaluation and management of recumbent horses are challenging. Familiarity with disorders that can result in recumbency will facilitate more rapid diagnosis and more appropriate formulation of a prognosis. With rapid and appropriate diagnosis, appropriate treatment can be pursued and, with good nursing care, can result in a favorable outcome.
TL;DR: EHV-1 infection has received a great deal of attention in the last decade due to several high-profile outbreaks, state-mandated quarantines, and recognition of a “neuroathogenic” strain.
Abstract: EHV-1 infection has received a great deal of attention in the last decade due to several high-profile outbreaks, state-mandated quarantines, and recognition of a “neuroathogenic” strain. This alpha-herpesvirus is ubiquitous throughout the world, and ost horses over the age of 2 years have been exposed. Latent infections involving he trigeminal ganglia and respiratory tract lymph nodes are common, and stressful vents may trigger reactivation. Although primarily a respiratory pathogen, responsile for fever, inappetence, and nasal discharge in young horses, EHV-1 is also ssociated with abortions, neonatal death, and neurologic disease, known as EHV-1 yeloencephalopathy (EHM). Disease is spread via aerosolization of respiratory ecretions or direct contact with infected horses or fomites. Virus moves from espiratory epithelial cells to regional lymph nodes to peripheral blood leukocytes, ausing a cell-associated viremia. When virus crosses from leukocytes into endotheial cells of the central nervous system (CNS), it causes vasculitis with hemorrhage and hrombosis that result in hypoxia and ischemia in surrounding CNS tissue. Typical linical signs include fever, paresis and ataxia (usually worse in pelvic limbs than horacic limbs), urinary bladder paralysis with urine dribbling, and decreased tail and nal tone with fecal retention. Severely affected horses may become recumbent or how evidence of brainstem involvement. Arguably the most important discovery in the last decade of EHV-1 research was he association of a point mutation in the EHV-1 genome with outbreaks of EHM. This mutation results in variation of a single amino acid of the DNA polymerase, such
TL;DR: Diabetes insipidus may not be a correctable disorder, and supportive care of affected horses requires an adequate water source.
Abstract: Diabetes insipidus (DI) is a rare disorder of horses characterized by profound polyuria and polydipsia (PU/PD), which can be caused by loss of production of arginine vasopressin (AVP). This condition is termed neurogenic or central DI. DI may also develop with absence or loss of AVP receptors or activity on the basolateral membrane of collecting-duct epithelial cells. This condition is termed nephrogenic DI. Equine clinicians may differentiate true DI from more common causes of PU/PD by a systematic diagnostic approach. DI may not be a correctable disorder, and supportive care of affected horses requires an adequate water source.