EPA + DHA supplementation reduces PMN activation in microenvironment of chronic venous leg ulcers: A randomized, double-blind, controlled study

Abstract

Sustained high levels of activated polymorphonuclear leukocytes (PMNs) and PMN-derived proteases in the microenvironment of chronic venous leg ulcers (CVLUs) are linked to chronic inflammation and delayed healing. Uncontrolled PMN activity eventually destroys newly developed tissue and degrades critical growth factors. The bioactive components of fish oil (n-3 eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) have strong inflammation-resolving actions and have been shown to assuage PMN activity, but have not been tested in CVLU patients. This randomized controlled study compared the effectiveness of oral EPA + DHA therapy to a placebo for reducing PMN activation in CVLU microenvironments. At Days 0, 28, and 56, markers of PMNs (CD15) and activated PMNs (CD66b), and levels of PMN-derived proteases human neutrophil elastase and matrix metalloproteinase-8 were measured in CVLU fluid from patients receiving standard compression therapy and (1) EPA + DHA therapy (n = 16) or (2) placebo (n = 19). By Day 56, the EPA + DHA Group had a significantly lower percentage of CD66b+ cells in CVLU fluid compared to Day 0 (p = 0.02) and to Day 28 (p = 0.05). Importantly, there were downward trends in levels of both matrix metalloproteinase-8 and human neutrophil elastase over time in the EPA + DHA Group, which also demonstrated greater reductions in wound area by Day 28 (57% reduction) and Day 56 (76% reduction) than the Control Group (35% and 59%, respectively). Moreover, reductions in wound area had significant negative relationships with CD15+ cells in wound fluid at Days 28 (p = 0.008) and 56 (p < 0.001), and CD66b+ cells at Days 28 (p = 0.04) and 56 (p = 0.009). The collective findings provide supplemental evidence that high levels of activated PMNs in CVLU microenvironments inhibit healing, and suggest that EPA + DHA oral therapy may modulate PMN activity and facilitate healing of CVLUs when added to standard care regimens.

Figure 1.

The CONSORT diagram illustrating the flow of patients who participated in the study.

Figure 2.

Comparison of levels of MMP-8 (A) and HNE (B) in wound fluid of venous leg ulcers at Days 0, 28, and 56 of the study between the EPA + DHA Group and the Control Group. The graph provides comparisons between the EPA + DHA Group and Control Group in terms of levels of MMP-8 and HNE (measured in ng per mg of albumin) at the study’s three time points. Each bar represents the mean ± SEM. (Student’s t test, EPA + DHA group: n = 16; Control Group: n = 19). MMP-8 = matrix metalloproteinase; HNE = human neutrophil elastase.

Figure 3.

Comparison of percent reduction in wound area at Day 28 and Day 56 of the study between the EPA+DHA Group and the Control Group. The graph provides comparisons between the EPA+DHA and Control Group in terms of percent reduction in wound area at Day 28 and Day 56 compared to Day 0. Each bar represents the mean percent reduction ± SEM. (Student’s t test, EPA+DHA Group: n = 16; Control Group: n = 19).