or of glycogen accumulation in equines; however Equine Metabolic Disease & Equine Polysaccharide Storage Myopathy are conditions that closely resembles the pre-Diabetic state seen in other mammals, though there is no evidence that there is a progression to Diabetes in horses. Lipid Accumulation Fatty change is described as an abnormal accumulation of lipids in parenchymal cells, where the intracellular lipid is stored in a central vacuole. Generally, this state is reversible once the instigating factor is removed. Most commonly fatty change is seen in cells of the as a response to stress. The liver is one of the areas in the body where beta-oxidation of free fatty acids (FFA’s) occurs. This makes the liver tissue sensitive to lipid imbalances in the diet. In situations of starvation, the liver breaks down the lipids in fat stores and in cell structures to use as energy. If there is an excess liberation of FFA’s, those not used for energy will be converted to triglycerides and stored in the parenchymal cells of the liver. An excess of lipids in the diet can lead to , and excess lipids are similarly stored in the liver cells. Liver failure may also cause fatty change as hepatic necrosis reduces the liver’s capacity to process FFA’s for storage in adipose tissue. Hyperlipemia may also cause lipid accumulation in the cardiovascular system. is deposited in the lumen of blood vessels as well as in the chambers of the heart causing increased resistance to blood flow, increased risk of thrombus formation, increased risk of aneurysm, and ultimately causing acute heart failure (a heart attack). A condition called is a result of hyperlipidemia. Xanthomas are masses formed by lipid accumulation in the macrophages’ residing in tendons and epithelial connective tissue. The central fat vacuole causes the macrophages to enlarge to a size that, if superficial, is palpable. Generally, a reduction in the intake of dietary lipids will halt the progression of a xanthoma, and over time the lipid deposition will reverse. Xanthomas can be formed as part of an autoimmune reaction or hypersensitivity reaction. in the synthesis and the degradation of structural proteins. An increase in protein synthesis without a corresponding increase in catabolism will result in the buildup of intracellular proteins. Dietary intake of protein seems to have no effect on the formation of protein accumulations. Most often protein accumulations are composed of the protein-polysaccharide complex amyloid, which has been linked to memory loss and Alzheimer’s disease in people. Protein accumulations of any kind are rare in horses; however, hypersensitivity reactions and autoimmune reactions involving structural proteins such as collagen may lead to an area of collagen deposition and granuloma formation. Protein Accumulation Generally, protein accumulation is caused by an
21
Made with FlippingBook Publishing Software