Session Information
Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Background/Purpose:
Polymyositis (PM) and dermatomyositis (DM) are chronic autoimmune diseases, characterized by muscle fatigue. Despite conventional immunosuppressive treatment including high doses of glucocorticoids, only a few patients completely recover muscle function. Our group has recently discovered that immunosuppressive treatment has significant effects on skeletal muscle gene expression related to lipid and fatty acid (FA) metabolism that may contribute to the persistent muscle weakness in myositis patients. Previous studies have described important effects of FAs on skeletal muscle growth, performance and inflammation. Nevertheless, the involvement of lipids and FA in the pathogenesis of PM and DM has not been elucidated. The aim of the study was to study lipid and FA profiles in sera from patients with PM or DM in comparison to healthy individuals and in relation to immunosuppressive treatment.
Methods:
Serum samples were obtained from 14 patients with established PM or DM with persisting muscle weakness and 12 age and sex matched healthy controls (HC). In a second cohort, serum samples were obtained from 8 new onset PM or DM patients before and after 6 months of conventional immunosuppressive treatment including glucocorticoids. Serum lipids were extracted by using liquid-liquid extraction. FA composition of total lipids was determined by gas chromatography flame ionization detector (GC-FID). FA composition of several lipid classes e.g., triacylglycerols, phospholipids, sphingolipids and lysophospholipids was analyzed by using liquid chromatography tandem mass spectrometry (LC-MS/MS).
Results:
Our preliminary results show that FA composition of total serum lipids was altered in myositis patients compared to HC; the levels of palmitic16:0 acid was significantly higher (p<0.05) in myositis patients whereas the levels of arachidonic 20:4(n-6) acid was significantly lower (p<0.05). Immunosuppressive treatment affected the FA profiles in total lipids and in lipid classes in the serum from myositis patients. The levels of eicosadienoic acid 20:2(n-6) and eicosapentaenoic 20:5(n-3) acids in myositis patients were significantly higher after treatment compared to before treatment (p<0.05). Moreover, the levels of phosphatidylcholine (PC) (32:1), phosphatidylethanolamine (PE) (36:5) and lysophosphatidylcholine (LPC) (16:1) were all significantly higher (p<0.05) in myositis patients after treatment compared to before.
Conclusion:
FA composition of total serum lipids was altered in myositis compared to HC. This could be explained by given immunosuppressive treatment as FA composition of serum PC, PE and LPC was altered after 6 months of treatment compared to before treatment. These data suggest that FA metabolism might be deregulated in PM and DM patients and this may contribute to impaired muscle performance and representing a potential therapeutic target in PM and DM.
To cite this abstract in AMA style:
Raouf J, Idborg H, Olsson P, Jakobsson PJ, Lundberg IE, Korotkova M. Altered Serum Fatty Acid Profiles in Patients with Polymyositis or Dermatomyositis Compared to Healthy Individuals and in Relation to Immunosuppressive Treatment [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/altered-serum-fatty-acid-profiles-in-patients-with-polymyositis-or-dermatomyositis-compared-to-healthy-individuals-and-in-relation-to-immunosuppressive-treatment/. Accessed .« Back to 2015 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/altered-serum-fatty-acid-profiles-in-patients-with-polymyositis-or-dermatomyositis-compared-to-healthy-individuals-and-in-relation-to-immunosuppressive-treatment/