دانلود رایگان مقاله ارزیابی پلاسمای آسیل کارتنین قبل و بعد از کاهش وزن در افراد چاق

Abstract

Acylcarnitines, fatty acid oxidation (FAO) intermediates, have been implicated in diet-induced insulin resistance and type 2 diabetes mellitus, as increased levels are found in obese insulin resistant humans. Moreover plasma acylcarnitines have been associated with clinical parameters related to glucose metabolism, such as fasting glucose levels and HbA1c. We hypothesized that plasma acylcarnitines would correlate with energy expenditure, insulin sensitivity and other clinical parameters before and during a weight loss intervention. We measured plasma acylcarnitines in 60 obese subjects before and after a 12 week weight loss intervention. These samples originated from three different interventions (diet alone (n = 20); diet and exercise (n = 21); diet and drug treatment (n = 19)). Acylcarnitine profiles were analysed in relation to clinical parameters of glucose metabolism, insulin sensitivity and energy expenditure. Conclusions were drawn from all 60 subjects together. Despite amelioration of HOMA-IR, plasma acylcarnitines levels increased during weight loss. HOMA-IR, energy expenditure and respiratory exchange ratio were not related to plasma acylcarnitines. However non-esterified fatty acids correlated strongly with several acylcarnitines at baseline and during the weight loss intervention (p < 0.001). Acylcarnitines did not correlate with clinical parameters of glucose metabolism during weight loss, questioning their role in insulin resistance and type 2 diabetes mellitus.

4. Discussion

In this study we have shown that plasma acylcarnitines increase in obese humans upon weight loss while insulin sensitivity improved. Additionally, acylcarnitines correlated positively with NEFA at baseline and over time. Several studies have reported that increased plasma acylcarnitine levels associate with obesity and insulin resistance [7,8,10,18]. In our study, plasma NEFA correlated positively with plasma C16-carnitine and other species, namely C2- , C14:1- and C18:1-carnitine. In the context of this strong correlation of acylcarnitines with plasma NEFA, which are known to induce insulin resistance, the overall absence of correlations between acylcarnitines and markers of insulin sensitivity is remarkable [19,20]. Since plasma NEFA are indicative of lipolysis, acylcarnitines in plasma may reflect white adipose tissue (WAT) breakdown [21]. As a result, NEFA released from WAT could drive FAO rates generating acylcarnitines.