Glutathione, Cysteine, and Ascorbate Concentrations in Clinically Ill Dogs and Cats

Abstract

Background: Oxidative stress plays a role in the pathogenesis of many systemic diseases. Hospitalized human patients are glutathione, cysteine, and ascorbate deficient, and antioxidant depletion has been correlated with poor clinical outcome. To date little is known about antioxidant concentrations in hospitalized veterinary patients. The purpose of this study was to determine whether ascorbate, cysteine, or glutathione depletion is present in ill dogs and cats compared with healthy controls.Hypothesis: Clinically ill dogs and cats would be antioxidant depleted, and depletion would correlate with illness severity and clinical outcome.Animals: Clinically ill client-owned dogs (n 5 61) and cats (n 5 37), healthy control dogs (n 5 37) and cats (n 5 33). Methods: Prospective, observational, case control study. Erythrocyte reduced glutathione, plasma cysteine, and plasma ascorbate were quantified using high-performance liquid chromatography.Results: Clinically ill dogs had significantly lower erythrocyte glutathione concentrations (1.22 mM, range 0.55-3.61) compared with controls (1.91 mM, range 0.87-3.51; P 5 .0004), and glutathione depletion correlated with both illness severity (P 5 .038) and mortality (P 5 .010). Cats had higher ascorbate concentrations when ill (10.65 mM, range 1.13-25.26) compared with controls (3.68 mM, range 0.36-13.57; P 5 .0009).Conclusions and Clinical Importance: Clinically ill dogs had decreased erythrocyte glutathione concentrations, which could be a marker of illness severity and prognostic of a poor outcome. Clinically ill cats had an unexpectedly high plasma ascorbate, which could represent a unique species response to oxidative stress.

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

“…Another study reported that GSH in cats, dogs, and humans were 1.97 ± 0.07, 1.98 ± 0.15, and 2.26 ± 0.09 mmol/L RBC, respectively (Harvey and Kaneko 1976). The study in clinically ill dogs also showed a decrease in erythrocyte glutathione concentration (Viviano et al 2009). …”

“…There was no association between age and oxidative stress parameters in the present study. In a study of clinically ill cats, there was no significant correlation between age and oxidative stress parameters (GSH, cysteine, and ascorbate concentration) (Viviano et al 2009). The most common breeds of CKD cats included domestic short hair and Siamese breed cats.…”

“…A study in 20 CKD cats demonstrated a higher reduced glutathione to oxidized glutathione (GSH/GSSG) ratio than the controls, while superoxide dismutase (SOD) values were the same (Keegan and Webb 2010). Viviano et al (2009) found high plasma ascorbate which represented the oxidative stress in clinically ill cats (Viviano et al 2009). In that study, two CKD cats in the clinically ill group were included (Viviano et al 2009).…”

“…Viviano et al (2009) found high plasma ascorbate which represented the oxidative stress in clinically ill cats (Viviano et al 2009). In that study, two CKD cats in the clinically ill group were included (Viviano et al 2009). Reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione peroxidase (GPx), and GSH/ GSSG ratio have also been used as the biomarkers for oxidative stress in many species (Fryer 1997;Sies 1997;Dounousi et al 2006).…”

Short-term culture of ovarian cortex pieces to assess the cryopreservation outcome in wild felids for genome conservation

“…For feline immunodeficiency virus-infected cells supplementation of Vitamin C resulted in an inhibition of apoptosis and virus replication [35]. Furthermore, the determination of ill cats showed a high ascorbate concentration in plasma which function as a potential species response to oxidative stress [36]. Our results, however, suggested the detrimental effect of Vitamin C supplementation on cat follicle survival (Figure 2) in the ovarian cortex.…”