Clinical determinants and mortality predictability of stearoyl-CoA desaturase-1 activity indices in dialysis patients

• Huang X, Stenvinkel P, Qureshi AR, Cederholm T, Barany P, Heimburger O, Lindholm B, Riserus U, Carrero JJ (Divisions of Renal Medicine and Baxter Novum, Department of Clinical Science, Intervention, and Technology, Karolinska Institutet, Stockholm; and Clinical Nutrition and Metabolism, Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden). Clinical determinants andmortality predictability of stearoyl-CoA desaturase-1 activity indices in dialysis patients. J InternMed 2013; 273: 263-272. Background 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. Subjects A total of 222 dialysis patients (39% women) with prospective follow-up, median age of 57years and an average of 12months of dialysis. Design Fatty acid compositions in plasma phospholipids and free fatty acids (FFAs) were assessed by gasliquid 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. Results 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 5.537.3) 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) 1.284.11 and HR 2.36, 95% CI 1.384.03, respectively], compared with patients with low SCD-1 indices. Conclusions 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.

Nyckelord

dialysis

fatty acids

inflammation

kidney disease

mortality

stearoyl-CoA desaturase-1

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