Oxidative stress after moderate to extensive burning in humans

Abstract

Lipid peroxidation products, lipid antioxidants, and hematologic and blood chemistry changes were evaluated in plasma of patients after acute burning injury involving 10% (n=8), 20% (n=8), and 40% (n=5) of total body surface area (TBSA), 24 h after burning (baseline) up to 30 days after. Markedly increased plasma levels of malondialdehyde (MDA) were observed at baseline in all patients, according to the extent of the injury, then the values declined progressively. However, levels of MDA remained above normal up to 30 days even in less injured patients. On the other hand, the plasma level of conjugated diene lipid hydroperoxides was only slightly higher than control at the baseline, then dropped under the control value in all patients. Cholesterol showed a marked fall at baseline, followed by a rapidly progressive decrease, indicating a massive loss of circulating lipids by the acute thermal injury. Because of such an extensive and rapidly spreading oxidative degradation of lipids, decomposition of conjugated diene hydroperoxides, produced in early stages of the peroxidation process, occurs, so these compounds cannot be a suitable index to value lipid oxidation in burned patients. Aldehydic products of lipid peroxidation act as endotoxins, causing damage to various tissues and organs. Damage to liver and decrease of erythrocyte survival were assessed by increased plasma levels of asparate and alanine transaminases, within 7-15 days after injury, and by a decreased number of red blood cells, which remained under the normal value at 30 days. A marked decrease of lipid antioxidants, beta-carotene, vitamin A and vitamin E was observed at baseline. The level of beta-carotene remained low in all patients at the end of the 30-day observation. A complete recovery of vitamin A did not occur at 30 days post-burn, even in the patients with 10% of burned TBSA. Plasma levels of vitamin E decreased significantly in 1-7 days after burn in all patients, but these levels increased thereafter, with almost total recovery at 30 days. These data show evidence of a marked, long-lasting oxidant/antioxidant imbalance in burned patients, in accordance with the severity of the injury, which is also reflected as systemic oxidant stress.

Etanercept protects remote organ damage in a rat model of thermal injury

“…Evidence from animal and human studies suggested that there is a correlation between the tissue MDA levels and the degree of burn complications, including shock and remote organ damage (32)(33)(34)(35). In the present study, burn-induced increase in the lung MDA levels were prevented by etanercept treatment, suggesting that antagonism of TNF- exerts a potent protective effect against lipid peroxidation.…”

Suplementação de antioxidantes: enfoque em queimados

“…A literatura tem sugerido que os oxidantes gerados contribuem para danos locais adicionais contribuindo na formação do edema. A ativação do sistema complemento, por sua vez, resultaria na inflamação de órgãos à distância 13,14 . Também a defesa antioxidante estaria enfraquecida nesse contexto 15 .…”

“…Uma diminuição de antioxidantes lipídicos (α-tocoferol, β-caroteno, vitamina A) e aumento da peroxidação lipídica também foram observados durante 30 dias em pacientes queimados, mesmo nos que exibiam apenas 10% de superfície corporal queimada 14 .…”

Melatonin protection against burn-induced liver injury. A review

“…There is evidence of both local and systemic oxidant changes manifested by increased free radical activity and lipid peroxidation [4,14]. At the same time, a burn injury causes a remarkable reduction of total antioxidant status and scavenging capacity.…”

“…Clinical investigations show that burn-induced hepatic injury is accompanied by impairment of hepatic parenchymal cell function [14,68]. Plasma levels of aminotransferases such as AST and ALT, as indicators of hepatic injury and functional disorders, are higher after burns [44].…”