High concentrations of glucose reduce the oxidative metabolism of dog neutrophils in vitro

Abstract

BackgroundDogs are commonly affected by hyperglycemic conditions. Hyperglycemia compromises the immune response and favors bacterial infections; however, reports on the effects of glucose on neutrophil oxidative metabolism and apoptosis are conflicting in humans and rare in dogs. Considering the many complex factors that affect neutrophil oxidative metabolism in vivo, we investigated in vitro the specific effect of high concentrations of glucose on superoxide production and apoptosis rate in neutrophils from healthy dogs.ResultsThe capacity of the neutrophils to reduce tetrazolium nitroblue decreased significantly in the higher concentration of glucose (15.13 ± 9.73% (8 mmol/L) versus 8.93 ± 5.71% (16 mmol/L)). However, there were no changes in tetrazolium nitroblue reduction at different glucose concentrations when the neutrophils were first activated with phorbol myristate acetate. High concentrations of glucose did not affect the viability and apoptosis rate of canine neutrophils either with or without prior camptothecin stimulation. This study provides the first evidence that high concentrations of glucose inhibit the oxidative metabolism of canine neutrophils in vitro in a manner similar to that which occurs in humans, and that the decrease in superoxide production did not increase the apoptosis rate.ConclusionsA high concentration of glucose reduces the oxidative metabolism of canine neutrophils in vitro. It is likely that glucose at high concentrations rapidly affects membrane receptors responsible for the activation of NADPH oxidase in neutrophils; therefore, the nonspecific immune response can be compromised in dogs with acute and chronic hyperglycemic conditions.

Role of Neutrophils on the Ocular Surface

“…Atherosclerosis is facilitated by hyperlipidemia-induced elevation of blood neutrophil count [ 137 ]. In diabetes, high blood glucose level affects the metabolism of neutrophils [ 138 ] and enhances transient neutrophil activation followed by the inhibition of cell activity [ 139 ]. Hyperglycemic condition primes neutrophils to produce more superoxide and cytokines and to form more neutrophil extracellular traps than in normoglycemic conditions [ 140 ].…”

Polymorphonuclear leukocyte isolation from venous blood of the dog

“…Percoll, colloidal silica particles coated with polyvinylpyrrolidone, is a gradient medium for separation of cells, subcellular particles and even viruses. Different Percoll dilutions are used for isolation of PMN from venous blood samples of different animals and human (Mosca and Forte, 2016;Cools-Lartigue et al 2013;Swamydas et al 2015;Sursal et al 2018). Feline neutrophils are successfully obtained using the Percoll dilutions (72%, 63%, 54%, and 45%) (Sursal et al 2018).…”

“…Canine neutrophils have been studied for different in vitro studies (Bosco et al 2013;Sheats et al 2015;Li et al 2018). The purpose of this study was to isolate neutrophils from venous blood samples of healthy dogs.…”

Efeito Do Plasma Rico Em Glicose Na Apoptose De Neutrófilos De Cães

“…Divergindo do presente estudo e demais relatos da literatura, neutrófilos caninos incubados com meio de cultura Nogueira et al (2013) Archives of Veterinary Science, v.18, n.2, p.27-32, 2013. enriquecido com glicose (16 mmol/L) não apresentaram alteração da taxa de apoptose (Bosco et al, 2013) e neutrófilos humanos incubados com altas concentrações de glicose plasmática no período de 30 minutos e 24 horas não resultou no aumento significativo da apoptose (Turina et al, 2006). É provável que tal divergência esteja associada ao fato desses autores terem avaliado o efeito da hiperglicemia sob os neutrófilos isolados e não em sangue total.…”