Author: Eric L. Kendig
Publisher:
Published: 2009
Total Pages: 210
ISBN-13:
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We are faced with a metabolic disease pandemic. The prevalence of obesity-related metabolic diseases has increased exponentially in the last 50 years, in large part from a sedentary lifestyle and consumption of a diet high in fat (HFD) and simple sugars. Many diet-induced metabolic diseases, such as type 2 diabetes, atherosclerosis and non-alcoholic fatty liver disease, are associated with obesity. The direct connection between metabolic diseases and obesity is in part related to the development of low grade inflammation and disruption of metabolic regulation caused by oxidative stress. Using mouse models, we demonstrate the therapeutic potential of antioxidants and over-the-counter anti-inflammatory drugs in targeting and preventing diet-induced metabolic disease, and conclude that oxidative stress and inflammation provide common etiological mechanisms and potential therapeutic targets for prevention or reversal of diet-induced metabolic diseases. Consumption of a HFD causes dramatic changes in physiology of an individual. In particular, dyslipidemia induced by consumption of a high-fat or unbalanced diet can cause alterations in the structure and function of adipose, vasculature, liver, and muscle. Chronic imbalance in plasma lipids can cause an oxidative response in these tissues through the induction of the NADPH oxidase (NOX) complex, producing superoxide anion (O2) in the cytoplasm. Chronic activation of NOX results in overproduction of reactive oxygen, which can alter expression of adipose tissue-derived cytokines and inflammatory mediators such as adiponectin, leptin, visfatin, resistin, TNF[alpha], IL-6, and IL-1[beta]. Disruption of these signals cause global modulation of metabolism, resulting in accumulation of lipid in muscle and liver, elevation of blood pressure, and insulin resistance. Treating mice with antioxidants and anti-inflammatory drugs prevents the development of obesity, insulin resistance, and dyslipidemia, suggesting that ablation of this common etiological factor in metabolic disease may prove a useful therapeutic strategy for disease prevention or reversal. The analgesic drug, acetaminophen (APAP), demonstrated the greatest effect in preventing HFD-induced metabolic disease in mice, likely through its combined anti-inflammatory and antioxidant potential. Other over-the-counter analgesic drugs and antioxidants were tested yielding similar results. One potentially important mechanism for APAPs protective effects is the inhibition of NOX activity in white adipose tissue, which may help to maintain normal adipose homeostasis. We have also examined the protective effects of endogenous antioxidant systems in preventing diet-induced metabolic disease. Mice lacking the modifier subunit [Gclm ( -/- )] of glutamate cysteine ligase (GCL) were fed a HFD for 10 weeks and compared to wildtype [Gclm (+/+)] mice. We found that Gclm ( -/- ) mice were resistant to diet-induced obesity and hepatic lipid accumulation. Gclm ( -/- ) mice also appeared to have higher basal metabolic rate, indicated by increased systemic oxygen consumption.Combined, these findings highlight the importance of oxidative stress in the development of diet-induced metabolic disease, and provide a common etiological target for development of new therapeutic strategies. Further characterization of the effects of oxidative stress in development of these diseases may provide more specific targets for prevention or reversal of HFD-induced metabolic diseases.
