Lp-PLA2 and MPO: The FM Practitioner's Guide to Arterial Inflammation Markers

Lp-PLA2 and MPO are blood markers tied to inflammation in atherosclerosis, and higher levels of each have been associated with cardiovascular events in outcome studies. Lp-PLA2 is an enzyme made by inflammatory cells that travels with LDL, while MPO is a leukocyte enzyme whose plasma level predicted cardiac events in emergency patients with chest pain.

This guide covers what each marker means, what the outcome studies show and how they compare with hs-CRP.

Lp-PLA2

Lipoprotein-associated phospholipase A2 (Lp-PLA2) hydrolyzes oxidized phospholipids in LDL, and its reaction products, lysophosphatidylcholine and oxidized nonesterified fatty acids, can drive inflammatory responses. A collaborative analysis of 32 prospective studies found Lp-PLA2 activity and mass were associated with coronary heart disease and vascular death, with associations similar in size to non-HDL cholesterol and partly dependent on lipids.

Lowering the enzyme with a drug has not helped. In SOLID-TIMI 52, darapladib added to optimal therapy after an acute coronary syndrome did not reduce major coronary events. Lp-PLA2 can still carry information as a risk marker.

Reference ranges and units differ by assay and laboratory, so interpret results against the ordering lab's ranges.

MPO

Myeloperoxidase (MPO) is a leukocyte enzyme that is elevated in culprit lesions that have fissured or ruptured. LDL modified by MPO oxidants is present in atherosclerotic lesions and induced endothelial dysfunction in laboratory studies.

In 604 emergency patients with chest pain, a single MPO measurement independently predicted myocardial infarction and major adverse cardiac events at 30 days and 6 months.

Reference ranges vary by laboratory, so interpret results against the ordering lab's ranges.

How Lp-PLA2 and MPO Compare With hs-CRP

In the chest pain study, MPO identified patients at risk even without myocardial necrosis, where C-reactive protein did not. An angiography study of 102 patients found higher coronary lesion severity scores in the hs-CRP positive group, so hs-CRP also tracks coronary disease. These markers are best read together with standard risk factors, and which to order is a decision for the treating clinician.

Diet and LDL Oxidation

A review of pomegranate polyphenols describes inhibition of LDL oxidation in atherosclerotic mice and in humans. Whether diet changes lower Lp-PLA2 or MPO specifically has not been shown in the studies cited here.

How HANS Handles Inflammatory Panel Documentation

HANS is a clinical AI copilot that runs beside your EMR. It drafts an interpretation for each cardiovascular marker on the panel, so an elevated Lp-PLA2 and an elevated hs-CRP read differently in the note.

Patient timelines show how Lp-PLA2 and MPO change over time, and HANS documents the trend alongside the interpretation.

FAQ

Do these markers replace hs-CRP?

No. The studies cited here measured them alongside standard risk factors, and interpretation stays with the treating clinician.

Does lowering Lp-PLA2 with a drug prevent heart attacks?

In the SOLID-TIMI 52 trial, inhibiting Lp-PLA2 with darapladib after an acute coronary syndrome did not reduce major coronary events.

How often should these markers be rechecked?

Retesting intervals are a decision for the treating clinician.

Are these markers covered by insurance?

Coverage varies by payer and indication. Check with the lab and the plan before ordering.

---

References

1. Zalewski A, Macphee C. Role of lipoprotein-associated phospholipase A2 in atherosclerosis. Arterioscler Thromb Vasc Biol. 2005, 25(5):923-31. PMID 15731492
2. Lp-PLA2 Studies Collaboration. Lipoprotein-associated phospholipase A2 and risk of coronary disease, stroke, and mortality. Lancet. 2010, 375(9725):1536-44. PMID 20435228
3. O'Donoghue ML et al. Effect of darapladib on major coronary events after an acute coronary syndrome (SOLID-TIMI 52). JAMA. 2014, 312(10):1006-15. PMID 25173516
4. Brennan ML et al. Prognostic value of myeloperoxidase in patients with chest pain. N Engl J Med. 2003, 349(17):1595-604. PMID 14573731
5. Abdo AI et al. Low-density lipoprotein modified by myeloperoxidase oxidants induces endothelial dysfunction. Redox Biol. 2017, 13:623-632. PMID 28818791
6. Razban MM et al. The relationship between serum levels of hs-CRP and coronary lesion severity. Clujul Med. 2016, 89(3):322-6. PMID 27547050
7. Aviram M et al. Pomegranate juice flavonoids inhibit low-density lipoprotein oxidation and cardiovascular diseases. Drugs Exp Clin Res. 2002, 28(2-3):49-62. PMID 12224378

---

Want to streamline your cardiovascular risk assessment workflow? See HANS pricing and features.