Divisions of Renal Medicine and Baxter Novum, Department of Clinical Science, Intervention, and Technology, Karolinska Institutet, Stockholm, Sweden.
J Intern Med. 2013 Mar;273(3):263-72. doi: 10.1111/j.1365-2796.2012.02573.x. Epub 2012 Aug 20.
Stearoyl-CoA desaturase-1 (SCD-1) converts dietary saturated fatty acids to monounsaturated fatty acids. Elevated SCD-1 activity thus signifies impaired fatty acid metabolism and excess saturated fat intake. In the general population, increased SCD-1 activity is associated with cardiovascular disease and mortality. The determinants and implications of SCD-1 activity in dialysis patients are unknown.
A total of 222 dialysis patients (39% women) with prospective follow-up, median age of 57 years and an average of 12 months of dialysis.
Fatty acid compositions in plasma phospholipids and free fatty acids (FFAs) were assessed by gas-liquid chromatography. SCD-1 activity indices were calculated as the product-to-precursor fatty acid ratio (palmitoleic acid/palmitic acid) in each fraction to reflect SCD-1 activities in the liver and adipose tissue.
Median hepatic and adipose tissue SCD-1 activity indices were 0.016 and 0.150, respectively. In multivariate analyses, SCD-1 was positively associated with age, female sex and serum interleukin-6 level. During 18.4 (interquartile range 5.5-37.3) months of follow-up, there were 61 deaths and 115 kidney transplants. The cut-off level for high SCD-1 indices was determined by receiver operating characteristic curve analyses. In fully adjusted competing risk models, patients with high SCD-1 indices in both phospholipids and FFAs had more than twofold increased mortality risk before kidney transplantation [hazard ratio (HR) 2.29, 95% confidence interval (CI) 1.28-4.11 and HR 2.36, 95% CI 1.38-4.03, respectively], compared with patients with low SCD-1 indices.
Both hepatic and adipose tissue SCD-1 activity indices independently predict mortality in dialysis patients. Further studies are warranted to determine whether reducing SCD-1 activity by dietary intervention (limiting saturated fat) could improve survival in dialysis patients.
硬脂酰辅酶 A 去饱和酶-1（SCD-1）将膳食中的饱和脂肪酸转化为单不饱和脂肪酸。因此，SCD-1 活性升高表明脂肪酸代谢受损和饱和脂肪摄入过多。在普通人群中，SCD-1 活性增加与心血管疾病和死亡率有关。在透析患者中，SCD-1 活性的决定因素及其影响尚不清楚。
共纳入 222 例接受前瞻性随访的透析患者（39%为女性），中位年龄 57 岁，平均透析时间为 12 个月。
通过气相色谱法评估血浆磷脂和游离脂肪酸（FFAs）中的脂肪酸组成。SCD-1 活性指数通过各馏分中产物与前体脂肪酸的比值（棕榈油酸/棕榈酸）计算得出，以反映肝脏和脂肪组织中的 SCD-1 活性。
中位肝组织和脂肪组织 SCD-1 活性指数分别为 0.016 和 0.150。多变量分析显示，SCD-1 与年龄、女性和血清白细胞介素-6 水平呈正相关。在 18.4 个月（四分位距 5.5-37.3）的随访期间，共有 61 例死亡和 115 例肾移植。通过受试者工作特征曲线分析确定了高 SCD-1 指数的截断值。在完全调整的竞争风险模型中，磷脂和 FFA 中 SCD-1 指数高的患者在接受肾移植前的死亡风险增加两倍以上[风险比（HR）2.29，95%置信区间（CI）1.28-4.11 和 HR 2.36，95% CI 1.38-4.03]，与 SCD-1 指数低的患者相比。
肝组织和脂肪组织 SCD-1 活性指数均可独立预测透析患者的死亡率。进一步的研究需要确定通过饮食干预（限制饱和脂肪）降低 SCD-1 活性是否可以改善透析患者的生存率。
