Topic:Laminitis
Laminitis is a complex and painful condition affecting the hooves of horses, characterized by inflammation and damage to the laminae, the soft tissue structures that secure the hoof wall to the coffin bone. This condition can lead to severe lameness and, in chronic cases, permanent structural changes within the hoof. Factors contributing to laminitis include metabolic disorders, excessive intake of carbohydrates, and mechanical overload, among others. The condition is diagnosed through clinical signs, radiographic imaging, and sometimes histopathological examination. Management strategies often involve dietary modifications, pain relief, and corrective hoof care. This page compiles peer-reviewed research studies and scholarly articles that explore the pathophysiology, risk factors, diagnostic approaches, and management strategies for laminitis in horses.
Plasma fructosamine concentrations in horses with pituitary pars intermedia dysfunction with and without laminitis. Plasma fructosamine concentration ([fructosamine]) is believed to reflect medium term, average blood glucose concentration and in a previous study was higher in horses with active laminitis than in normal horses. Pituitary pars intermedia dysfunction (PPID) is associated with hyperglycaemia and laminitis. Objective: To test the hypotheses that: [fructosamine] is higher in PPID cases than normal animals; furthermore, that within cases of PPID [fructosamine] is higher in those with active laminitis than nonlaminitic cases and in cases that have been affected by active laminitis in the preceding ...
Hypertensive cardiomyopathy in horses: 5 cases (1995-2011). To describe the prognosis and clinical, echocardiographic, and pathological features of hypertensive cardiomyopathy in horses. Methods: Retrospective case series. Methods: 5 horses with cardiac hypertrophy and systemic hypertension. Methods: Demographics, history, physical and cardiological examination findings, diagnosis, clinical progression, prognosis, and pathological findings were obtained from medical records. Results: The primary diagnosis was chronic laminitis in 3 horses and chronic renal failure in 2. Persistent tachycardia, hypertension, chronic laminitis, or a combination of these ...
Therapeutic use of stem cells in horses: which type, how, and when? Stem cells are commonly used in equine practice to treat musculoskeletal disorders including tendonitis, osteoarthritis, and more recently laminitis. As the field of regenerative medicine continues to advance, equine practitioners need contemporary information regarding the choice of stem cell type and recommendations regarding clinical implementation of stem cell therapies. Clinicians must also be aware of the limitation in current knowledge regarding stem cells, and the impending regulatory laws that may limit the use of equine stem cells in clinical patients.
Cellular and humoral immunity in chronic equine laminitis. Chronic equine laminitis causes persistent pain and lameness in affected animals and often necessitates euthanasia when pain management strategies become ineffective. Published studies as well as anecdotal reports suggest that this chronic inflammatory disease is associated with systemic alterations in immune responsiveness, perhaps involving an autoimmune component. We investigated this broad hypothesis by measuring a variety of immune indicators in healthy control horses (CON) and horses with chronic laminitis (LMN). We found that white blood cells from LMN horses produced more IFNγ than di...
Fructokinase, Fructans, Intestinal Permeability, and Metabolic Syndrome: An Equine Connection? Fructose is a simple sugar present in honey and fruit, but can also exist as a polymer (fructans) in pasture grasses. Mammals are unable to metabolize fructans, but certain gram positive bacteria contain fructanases and can convert fructans to fructose in the gut. Recent studies suggest that fructose generated from bacteria, or directly obtained from the diet, can induce both increased intestinal permeability and features of metabolic syndrome, especially the development of insulin resistance. The development of insulin resistance is driven in part by the metabolism of fructose by fructokinase...
Seasonal variation in maintenance of phenylephrine-induced tone in isolated equine digital arteries under hypoxic or hyperoxic conditions in vitro. Digital vasoconstriction, ischaemia and hypoxia may predispose to acute laminitis. Laminitis incidence varies seasonally, peaking in spring and summer. Direct seasonal influences on equine digital artery (EDA) contractility have not been investigated. This study assessed seasonal variation in maintenance of phenylephrine (PHE)-induced tone in isolated EDAs under hypoxic (95% nitrogen) and hyperoxic (95% oxygen) conditions. The objective was to measure change in arterial tone over time after constriction to a plateau with PHE. Tone was measured at plateau and over time and percentage change cal...
Relationships between body condition score and plasma inflammatory cytokines, insulin, and lipids in a mixed population of light-breed horses. Obesity and hyperinsulinemia increase the risk of laminitis in horses and ponies. In mares, obesity also has been associated with increased circulating concentrations of the proinflammatory cytokine, tumor necrosis factor (TNF)-α. The association of other proinflammatory cytokines with body condition score (BCS) and insulin requires further determination. Objective: Plasma concentrations of TNF, interleukin (IL)-1β, IL-6, and serum amyloid A (SAA) will positively correlate with BCS or insulin or both in horses. Furthermore, inflammatory protein concentrations will correlate with age and vari...
Pyrosequencing of 16S rRNA genes in fecal samples reveals high diversity of hindgut microflora in horses and potential links to chronic laminitis. The nutrition and health of horses is closely tied to their gastrointestinal microflora. Gut bacteria break down plant structural carbohydrates and produce volatile fatty acids, which are a major source of energy for horses. Bacterial communities are also essential for maintaining gut homeostasis and have been hypothesized to contribute to various diseases including laminitis. We performed pyrosequencing of 16S rRNA bacterial genes isolated from fecal material to characterize hindgut bacterial communities in healthy horses and those with chronic laminitis. Results: Fecal samples were collected...
A review of recent advances and current hypotheses on the pathogenesis of acute laminitis. With the increasing number of studies being published on the different experimental models used to induce and study acute laminitis, the pathophysiological events associated with these various models (i.e. starch overload, oligofructose overload, black walnut extract and hyperinsulinaemia) can be compared more realistically. Within this review, the mechanisms for metabolic vs. inflammatory laminitis are discussed, and the question of how pasture laminitis may fit into any of the proposed mechanisms is addressed.
Case series of equine pituitary pars intermedia dysfunction in a tropical climate. The clinical manifestations of equine pituitary pars intermedia dysfunction (PPID) in temperate climates are well described. The classic presentation is that of an older animal with hirsutism, laminitis, poor muscle tone, pendulous abdomen and weight loss. This case series highlights the additional clinical signs of anhidrosis and heat stress with secondary exercise intolerance that were seen as primary presenting problems in equids with PPID in the hot, humid conditions of a tropical climate. The clinical signs resolved with medical treatment for PPID.
Plasma proteomics shows an elevation of the anti-inflammatory protein APOA-IV in chronic equine laminitis. Equine laminitis is a devastating disease that causes severe pain in afflicted horses and places a major economic burden on the horse industry. In acute laminitis, the disintegration of the dermal-epidermal junction can cause the third phalanx to detach from the hoof wall, leaving the horse unable to bear weight on the affected limbs. Horses that survive the acute phase transition into a chronic form of laminitis, which is often termed "founder". Some evidence suggests that chronic laminar inflammation might be associated with alterations in the endocrine and immune systems. We investigated th...
Effects of the addition of endotoxin during perfusion of isolated forelimbs of equine cadavers. To examine the effect of endotoxins on metabolism and histopathologic changes of isolated perfused equine forelimbs. Methods: Forelimbs (comprising the metacarpus and digit) were collected from cadavers of 12 healthy adult horses after slaughter at an abattoir (14 limbs; 1 forelimb of 10 horses and both forelimbs of 2 horses). Methods: Forelimbs were perfused for 10 hours with autologous blood, with and without the addition of endotoxin (80 ng of lipopolysaccharide [LPS]/L). Two limbs of the endotoxin exposure group and 2 nonperfused limbs were loaded to failure of the suspensory apparatus of ...
Histological and morphometric lesions in the pre-clinical, developmental phase of insulin-induced laminitis in Standardbred horses. Lamellar pathology in experimentally-induced equine laminitis associated with euglycaemic hyperinsulinaemia is substantial by the acute, clinical phase (∼48h post-induction). However, lamellar pathology of the developmental, pre-clinical phase requires evaluation. The aim of this study was to analyse lamellar lesions both qualitatively and quantitatively, 6, 12 and 24h after the commencement of hyperinsulinaemia. Histological and histomorphometrical analyses of lamellar pathology at each time-point included assessment of lamellar length and width, epidermal cell proliferation and death, base...
Measurement of digital laminar and venous temperatures as a means of comparing three methods of topically applied cold treatment for digits of horses. To compare effects of 3 methods of topically applied cold treatment (cryotherapy) on digital laminar and venous temperatures in horses. Methods: 9 healthy adult Thoroughbreds. Methods: Thermocouples were placed in palmar digital veins and digital laminae of both forelimbs of horses. Three methods of cryotherapy were applied to the distal aspects of the limbs: wader boot (63-cm-tall vinyl boot filled with ice and water [ice slurry]), ice bag (5-L fluid bag filled with ice slurry), and a gel pack boot (boot containing frozen gel packs). Gel packs and ice slurries were replenished every hour duri...
Evaluation of coronary band temperatures in healthy horses. To measure coronary band temperature (CBT) in healthy horses fed high-fructan or low-carbohydrate diets and to analyze the association of CBT with diet, time of day, and ambient temperature. Methods: 6 healthy horses. Methods: Horses were fed 3 diets (treatment 1, 1 g of fructan/kg fed daily in the morning; treatment 2, 1 g of fructan/kg fed daily in the afternoon; and treatment 3, a low-carbohydrate [7.2%] diet) in a 3 × 3 Latin square study design. For each horse, the CBT of all 4 limbs as well as rectal and ambient temperatures were recorded by use of infrared thermometry and standard ther...
Effect of ketamine hydrochloride on the analgesic effects of tramadol hydrochloride in horses with signs of chronic laminitis-associated pain. To investigate the effects of ketamine hydrochloride on the analgesic effects of tramadol hydrochloride in horses with signs of pain associated with naturally occurring chronic laminitis. Methods: 15 client-owned adult horses with chronic laminitis. Methods: Each horse received tramadol alone or tramadol and ketamine in a randomized, crossover study (≥ 2 months between treatments). Tramadol (5 mg/kg) was administered orally every 12 hours for 1 week. When appropriate, ketamine (0.6 mg/kg/h) was administered IV for 6 hours on each of the first 3 days of tramadol administration. Noninvasive sy...
Managing obesity in pasture-based horses. Obesity - a common problem in pasture-based horses - warrants intervention because it is associated with an increased risk for development of laminitis. Treating obesity in pasture-based horses is relatively simple and generally involves reducing caloric intake by using grazing muzzles and/or increasing caloric expenditure through exercise. To prevent recurrence of obesity after weight loss, clients should be educated on how to monitor body condition and to adjust feeding and management programs to maintain proper body condition.
Advanced glycation endproducts in horses with insulin-induced laminitis. Advanced glycation endproducts (AGEs) have been implicated in the pathogenesis of cancer, inflammatory conditions and diabetic complications. An interaction of AGEs with their receptor (RAGE) results in increased release of pro-inflammatory cytokines and reactive oxygen species (ROS), causing damage to susceptible tissues. Laminitis, a debilitating foot condition of horses, occurs in association with endocrine dysfunction and the potential involvement of AGE and RAGE in the pathogenesis of the disease has not been previously investigated. Glucose transport in lamellar tissue is thought to be l...
[Growth of the hoof horn in horses with chronic laminitis]. Objective of the study was to investigate whether a correlation between rotation and/or sinking of the third phalanx (P3) and changes of horn growth on the hoof wall exists. Methods: In 117 hooves of euthanatized or slaughtered horses with chronic laminitis the rotating angle to palmar/plantar and medial/lateral and a sinking of P3 were assessed on radiographs. Defined distances were measured on the dorsal hoof wall as well as in the heel to assess the horn growth of a hoof. On the basis of saw cuts of the hooves, the course of the horn tubes was judged. Results: A rotation angle of approximat...
Basal glucose metabolism and peripheral insulin sensitivity in equine pituitary pars intermedia dysfunction. Glucocorticoids are suggested to precipitate laminitis and induce insulin resistance in horses. Objective: To assess insulin sensitivity and the basal amount of glucose metabolized in equine pituitary pars intermedia dysfunction (PPID). Methods: The euglycaemic hyperinsulinaemic clamp (EHC) technique was performed in seven horses with a diagnosis of PPID based on the presence of hypertrichosis and positive dexamethasone suppression-test results comprising one gelding and six mares with a mean age of 21.1 ± 5.8 (SD; range 15-34) years. Results were compared with those from five negative (h...
Clenbuterol toxicosis in three Quarter Horse racehorses after administration of a compounded product. 3 Quarter Horse racehorses were examined for suspected clenbuterol overdose 12 to 24 hours after administration by mouth of a compounded clenbuterol product. Results: All horses developed sinus tachycardia, muscle tremors, hyperhidrosis, and colic. Abnormalities on serum biochemical analysis included hyperglycemia, azotemia, and high creatine kinase activity. The presence of clenbuterol in the serum of all 3 horses and in the product administered was confirmed and quantified by use of liquid chromatography-electrospray tandem mass spectrometry. Results: Propranolol (0.01 mg/kg [0.005 mg/lb], I...
The prevalence of endocrinopathic laminitis among horses presented for laminitis at a first-opinion/referral equine hospital. Endocrinopathic causes of laminitis may be a common underlying causative pathogenesis in first-opinion or field cases presenting with laminitis, as opposed to laminitis produced in inflammatory research models. This study aimed to determine whether evidence of an underlying endocrinopathy was present in horses presented for laminitis to a first-opinion/referral veterinary teaching hospital. A second aim was to compare the signalment of horses and ponies with laminitis with the equine hospital population during the same period. All horses presenting for laminitis at Helsinki University Equine T...
Cortisol, adrenocorticotropic hormone, serotonin, adrenaline and noradrenaline serum concentrations in relation to disease and stress in the horse. No detailed comparative data are available on the hormonal parameters of horses suffering from a number of diseases. The aim of our study was to measure concentrations of cortisol, adrenocorticotropic hormone (ACTH), serotonin, adrenaline and noradrenaline in horses with various diseases and following surgery, to assess the response of the HPA axis and adrenal medulla. Blood samples were obtained from six groups of horses comprising a total of 119 animals as follows: laminitis, acute abdominal syndrome (AAS), castration surgery, acute diseases, chronic diseases and healthy controls. Serum horm...
Role of oxidative tissue injury in the pathophysiology of experimentally induced equine laminitis: a comparison of 2 models. Oxidative stress reportedly plays a role in sepsis-induced organ dysfunction and failure in many species. In septic horses, laminae are targeted; evidence of laminar oxidative stress has been reported experimentally in the black walnut extract (BWE) model. Carbohydrate (CHO)-induced laminitis may be more similar to clinical sepsis-related laminitis than the BWE model in that animals with CHO-induced disease commonly develop laminar failure. The role of oxidative stress in the CHO model remains unknown. Objective: Markers of oxidative stress will be increased in laminae from horses with BWE- an...
Equine metabolic syndrome. 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 lami...
Effects of a supplement containing chromium and magnesium on morphometric measurements, resting glucose, insulin concentrations and insulin sensitivity in laminitic obese horses. Obesity and insulin resistance are risk factors for laminitis in equids and supplements containing chromium and magnesium might improve insulin sensitivity. Objective: A supplement containing chromium, magnesium and other nutraceuticals would alter morphometric measurements, blood variables, and insulin sensitivity in laminitic obese horses. Methods: Twelve previously laminitic obese (body condition score ≥ 7/9) horses were randomly allocated to treatment (n = 6) and control (n = 6) groups and 2 obese horses with clinical laminitis were included in the treatment group. Treated animals receiv...
Dietary supplementation with short-chain fructo-oligosaccharides improves insulin sensitivity in obese horses. Obesity and insulin resistance are risk factors for laminitis in horses and ponies, and diet can play an important role in modulating these risk factors. Dietary supplementation with prebiotic fibers, such as short-chain fructo-oligosaccharides (scFOS), has resulted in improvement of insulin sensitivity in obese dogs and rodents. Thus, we hypothesized that scFOS may reduce insulin resistance in obese horses and designed a study to evaluate the effect of dietary supplementation with scFOS on insulin sensitivity. Eight mature Arabian geldings (BW = 523.0 ± 56.5 kg) with an average BCS of 8 were...
Field treatment and management of endocrinopathic laminitis in horses and ponies. Endocrinopathic laminitis in horses and ponies has the potential to cause extensive damage to the feet before clinical signs of laminitis are apparent. Early diagnosis and intervention based on the detection and control of hyperinsulinemia are critical if the crippling changes that are seen in the disease are to be avoided. Preventing endocrinopathic laminitis, rather than treating it, is good practice management benefiting not only equine patients but also their owners.
Pasture management to minimize the risk of equine laminitis. The sugar, starch, and fructan content (collectively referred to as nonstructural carbohydrates [NSC]) of pasture plants is dependent on the environmental conditions under which they have grown. Pasture that is stressed by cold, drought, or lack of nutrients can be 2 to 3 times higher in NSC than pasture that grows quickly in warm weather and is adequately watered and fertilized. Horses at risk for laminitis should have access to pasture limited or be removed completely when environmental conditions are conducive to high levels of NSC accumulation.