Heinz Body Formation Associated With Ketoacidosis in Diabetic Cats

Abstract

Oxidative damage plays an important role in the pathophysiology of diabetes and diabetic complications. Feline hemoglobin is uniquely susceptible to oxidative denaturation; therefore, Heinz body formation is a highly sensitive indicator of in vivo oxidative stress in this species. Heinz bodies also contribute to anemia. We investigated hematological and clinical biochemical changes in 30 cats with spontaneous diabetes mellitus (as compared to 15 healthy control cats) and evaluated the relationship of these changes to erythrocyte oxidative damage. Cats were categorized as ketoacidotic or nonketoacidotic based on their clinical presentation and the presence of urine ketones. Ketoacidotic cats had significantly (P = .0009) more Heinz bodies (28.3% f 9.1 %) than nonketotic diabetic cats (6.5% f 1.60%) and healthy control cats (0.6% +-0.2%). Percent Heinz bodies in diabetic cats directly correlated with xygen radical-mediated processes may be im-0 portant in the pathogenesis of diabetes mellitus, and have been implicated in the development of diabetic complications in humans and animals, including cats.'-4 Glucose autooxidation, particularly in the presence of transition metals, is an important source of oxygen radicals that may contribute to the oxidative modification of nonenzymatically glycated prot e i n~.~-~ Oxidative stress in diabetic patients may also result from compromised antioxidant systems, oxidation of plasma lipoproteins, alterations in inflammatory mediators, and changes in antioxidant nutrientIn human red blood cells (RBCs), glycohemoglobin has been associated with increased mem-

Oxidative status of erythrocytes, hyperglycemia, and hyperlipidemia in diabetic cats

“…Hence, the increased concentrations of membrane carbonyls and decreased concentrations of cytoplasmic thiols in the erythrocytes of diabetic cats in the present study clearly suggests that oxidative stress occurs in untreated diabetic cats at the time of diagnosis, similar to findings in humans with type 1 and type 2 DM . It is difficult to explain why differences were not evident in previous studies, particularly when diabetic cats were considerably older and had higher body weight . Aging and obesity in humans are associated with increased oxidative stress of erythrocytes, and thus differences would have been expected in older and heavier cats …”

“…To date, there are limited data substantiating the presence of oxidative stress in diabetic cats . In the present study, erythrocytes of newly diagnosed diabetic cats had higher concentrations of membrane carbonyls and lower levels of cytoplasmic TBAR and thiols compared with well‐matched healthy controls.…”

“…Peroxidation of polyunsaturated fatty acids leading to generation of ketones and aldehydes, including malondialdehyde, has been frequently described in humans with type 1 and type 2 DM . In contrast, studies of diabetic cats showed that the concentrations of TBAR in erythrocytes and malondialdehyde in whole blood were similar to those in controls . Known differences between erythrocytes of cats and humans do not help explain this finding; feline hemoglobin contains 8 free reactive sulfhydryl groups, whereas human hemoglobin has only 2 .…”

The Endocrine and Metabolic Systems

“…119 The number of Heinz bodies directly correlates with β-hydroxybutyrate concentrations from ketoacidosis. 120 Management. The management of diabetes in cats is similar to that in dogs, except that 20% to 50% of diabetic cats do not require insulin.…”

Diabetic Ketoacidosis

“…2 Anemia and neutrophilia with a left shift are also common features of feline DKA. 9 Persistent hyperglycemia is apparent in all dogs and cats diagnosed with DKA unless they have received insulin. 9 Persistent hyperglycemia is apparent in all dogs and cats diagnosed with DKA unless they have received insulin.…”