Altered monocyte CD44 expression in peripheral arterial disease is corrected by fish oil supplementation

Background and aims: CD44 and its splice variants can be expressed on all leukocytes, conferring adhesive properties and enhancing cellular recruitment to the endothelium during inflammation. CD44 expression is increased in inflammatory conditions such as rheumatoid arthritis and CD44 variant 3 (CD44v3) expression may be associated with inflammation. We have examined CD44 and CD44v3 expression on peripheral blood monocytes from patients with peripheral arterial disease (PAD) and healthy controls. We have also examined the effect of fish oil supplementation on these markers. Methods and results: CD44 and CD44v3 were assessed at baseline and following dietary supplementation with fish oil for 12weeks in both PAD and control groups. Monocytes from PAD patients had higher CD44 expression than those from controls (median intensity fluorescence (MIF): 480+/-278 vs 336+/-251 (mean+/-SD); p<0.001). Following 12weeks dietary supplementation with fish oil, CD44 expression was reduced in PAD patients (MIF: 480+/-278 vs 427+/-262; p=0.05) but not in controls (336+/-251 vs 355+/-280; ns). Monocyte CD44v3 expression was lower in cultured monocytes from PAD patients compared to those from controls (0.15+/-0.15 vs 0.22+/-0.14 OD units; p<0.02). This was increased in the PAD group following fish oil supplementation (0.15+/-0.14 to 0.27+/-0.23 OD units; p<0.001). Conclusion: Monocyte CD44 and CD44v3 expression are altered in arterial disease but are returned towards levels seen in control subjects by dietary fish oil supplementation