Preliminary study of an increase of a plasma apolipoprotein E variant associated with peripheral nerve damage. A finding in patients with chronic spinal pain.
STUDY DESIGN: This two-dimensional gel electrophoretic study analyzed the plasma of six groups of patients to determine the association of an elevated apolipoprotein E variant with peripheral nerve damage (PND). OBJECTIVES: To find a statistically significant plasma protein alteration in patients with PND including chronic spinal pain. SUMMARY OF BACKGROUND DATA: A twofold to fivefold increase in human plasma apolipoprotein E may be a physiologic response to PND as a 250-fold local increase in apolipoprotein E was reported in experimental PND studies in mammals. METHODS: A total of 36 patients with chronic lumbar pain, 28 normal control subjects, and 33 patients with other conditions were studied. Venipuncture was performed and plasma was studied using the technique of two-dimensional gel electrophoresis. Chi-square analysis was used to evaluate results. RESULTS: A statistically significant (P < 0.005) elevation of the plasma apolipoprotein E variant was found in patients with chronic lumbar pain. It also was elevated in patients with chronic cervical pain, extraspinal pain with PND, and chronic inflammatory diseases; but not in extraspinal pain without PND, or asymptomatic biomechanically deficient lumbar spines. CONCLUSIONS: This quantitative protein alteration, although not specific for PND, may prove useful in the treatment of conditions with this disorder, including chronic spinal pain.