LACTATE CAN BE A MARKER OF METABOLIC SYNDROME IN SEVERE OBESITY?

ABSTRACT Background: In the last decades, numerous studies have confirmed the importance of lactate - by-product to the nutrient signal of the intracellular redox state - to regulatory functions in energy metabolism. Aim: To evaluate changes in blood lactate in patients with severe obesity and its correlation with body composition and metabolic profile. Methods: Twenty-four people with severe obesity (BMI=40 kg/m2) were evaluated in a prospective case-control study before and six months after Roux-in-Y gastric bypass. The blood lactate, total cholesterol, and fractions, C-reactive protein and HOMA-IR were analyzed after 12 h fasting. Body mass composition was evaluated by bioelectrical impedance and respiratory quotient was measured by indirect calorimetry. Results: The initial lactate level was 2.5±1.1 mmol/l and returned to normal level (1.9±3.6 mmol/l, p=0.0018) after surgery. This reduction was positively correlated with a decrease in BMI (p=0.0001), % free fat mass (p=0,001), % fat mass (p=0.001) and HOMA-IR (p=0.01). There was normalization of lactatemia in 70% of patients. There was no correlation between lactatemia and C-reactive protein. Conclusions: There was a significant improvement of metabolic parameters, normalization of blood lactate, fat mass loss, although these individuals remained with a high BMI.摘要 背景：过去数十年间，多项研究已证实乳酸（lactate）——作为细胞内氧化还原状态（intracellular redox state）营养信号的副产物——在能量代谢调控功能中的重要性。 研究目的：评估重度肥胖患者血液乳酸水平的变化，及其与身体成分和代谢特征（metabolic profile）的相关性。 研究方法：本研究为前瞻性病例对照研究，共纳入24名重度肥胖患者（体质量指数（Body Mass Index, BMI）=40 kg/m²），分别于Roux-en-Y胃旁路术（Roux-in-Y gastric bypass）术前及术后6个月进行评估。受试者空腹12小时后采集血液样本，检测血液乳酸、总胆固醇及其组分、C反应蛋白（C-reactive protein）以及胰岛素抵抗稳态模型评估指数（HOMA-IR）。采用生物电阻抗法（bioelectrical impedance）评估体成分，通过间接测热法（indirect calorimetry）测定呼吸商（respiratory quotient）。 研究结果：受试者初始血乳酸水平为2.5±1.1 mmol/L，术后恢复至正常水平（1.9±3.6 mmol/L，p=0.0018），差异具有统计学意义。该乳酸水平降幅与体质量指数（p=0.0001）、去脂体重百分比（p=0.001）、体脂百分比（p=0.001）及HOMA-IR（p=0.01）的降幅呈正相关。70%的患者术后血乳酸水平恢复正常。血乳酸水平与C反应蛋白未发现显著相关性。 结论：尽管此类患者仍存在较高的体质量指数，但其代谢参数得到显著改善，血乳酸水平恢复正常，体脂含量显著减少。