Oxidative stress and innate immunity in feline patients with diabetes mellitus: The role of nutrition

Abstract

This study was undertaken to test the hypothesis that oxidative stress is increased and neutrophil function is decreased in cats with diabetes mellitus (DM). Measures of oxidative stress and neutrophil function were evaluated in 20 control and 15 diabetic cats. Cats were then fed a diet designed specifically for feline diabetics (Purina DM Dietetic Management Feline Formula) for 8 weeks, after which all assays were repeated. Cats with DM had significantly less plasma superoxide dismutase (SOD) than control cats, consistent with a greater degree of oxidative stress in the DM group. Following 8 weeks of consuming a diabetes-specific diet glutathione peroxidase, an antioxidant enzyme increased significantly in both groups. Other parameters of oxidative stress, as well as neutrophil function, were similar between groups and did not change following dietary intervention. The DM cats were significantly older and heavier than the control cats, which may have contributed to differences in parameters of oxidative stress and levels of antioxidant enzymes between these groups, but the decreased level of SOD enzyme in the diabetic group would appear to support the continued development of targeted antioxidant supplementation for this cats with this disease.

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 .…”

Changes in reduced glutathione, oxidized glutathione, and glutathione peroxidase in cats with naturally occurring chronic kidney disease

“…A study of glutathione and glutathione-related enzymes in patients on maintenance dialysis found that plasma GPx activity was significantly lower in the dialysis group than in the healthy control group (Ahmadpoor et al 2009). A study of oxidative stress in cats with diabetes mellitus (DM) also reported that plasma GPx levels in the DM cats were lower than in the control cats (Webb and Falkowski 2009 Fig. 4 Regression analysis between creatinine and GSH/ GSSG ratio in the clinically normal cats (dark blue) and CKD cats (blue).…”

Serum biomarkers of oxidative stress in cats with feline infectious peritonitis

“…In this situation the organism is unable to detoxify reactive oxygen species, which accumulate, producing a harmful effect on the functional and structural integrity of biological tissues (Yilmaz, 2012). Cats seem to be more susceptible to oxidative stress and damage, probably influenced by the particular spleen structure of this species (Christopher et al, 1995;Harvey and Kaneko, 1977), and a situation of oxidative stress has been demonstrated in various diseases in this species such as diabetes mellitus (Webb and Falkowski, 2009), chronic renal failure (Keegan and Webb, 2010) and feline immunodeficiency virus (FIV) infection (Webb et al, 2008). However, to the author's knowledge there are no studies about oxidative stress in feline infectious peritonitis (FIP), a viral disease resulting from feline coronavirus (FCoV) infection.…”