The potential value of blood biomarkers of intervertebral disk metabolism in the follow-up of patients with sciatica.
METHODS
This is a prospective study with a follow-up period of 4 years.


OBJECTIVE
The study aimed to evaluate the possible clinical utility of three biomarkers [i.e., keratan sulfate (KS), hyaluronan, and cartilage oligomeric matrix protein] measured in peripheral blood in severe acute sciatica at intake and follow-up.


BACKGROUND
Our previous study and others have pointed out the interest of different laboratory tests in the acute phase of sciatica. Several blood biomarkers have been reported useful in the long-term follow-up of patients with osteoarthritis. We have found no information about the potential interest of these tests in spinal disorders.


METHODS
Patients were admitted to the hospital for intensive conservative management of acute sciatica (n=82). A subgroup of patients (n=33) was selected based on the duration of symptoms at visit 1, and included those with the shortest (n=24) as well as those with the longest (n=9) duration of sciatica. Blood samples were drawn, centrifuged, and the plasma frozen. Antigenic KS, hyaluronan, and cartilage oligomeric matrix protein were measured by ELISA. Patients were re-evaluated at an average of 4.3 years (range: 2.1-6.8 years).


RESULTS
Thirty-three subjects with an average age of 49.2+/-10.2 years participated. At intake, levels of the three biomarkers evaluated were within the range of normal values. No significant differences were found between the results of patients with a short history of sciatica (< or =3 weeks) and those with a long duration of symptoms (>20 weeks). At follow-up, a significant increase (P<0.05) in all three biomarkers was found.


CONCLUSIONS
A single measurement of these three biomarker molecules does not seem to have any diagnostic or therapeutic relevance in patients with acute radicular compression. The significance of the increase in all three biomarkers after a mean follow-up of 4.3 years is unclear; it might reflect metabolic processes involved in degenerative spinal disorders. Even though we found no correlation with clinical outcome, we believe that more research is needed.
Service de Rhumatologie, Médecine Physique et Rééducation, Hôpital cantonal de Fribourg, 1708 Fribourg, Switzerland. balaguef@hopcantfr.ch
Federico
F
Balagué
Margareta
M
Nordin
Dominique
D
Schafer
Ali
A
Sheikhzadeh
Mary Ellen
ME
Lenz
Eugene M A
EM
Thonar
D000328:Adult; D015415:Biomarkers / Q000097:blood; D064236:Cartilage Oligomeric Matrix Protein; D004797:Enzyme-Linked Immunosorbent Assay; D005109:Extracellular Matrix / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000032:analysis / Q000097:blood; D005260:Female; D051445:Fibrocartilage / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D005500:Follow-Up Studies; D006023:Glycoproteins / Q000032:analysis / Q000097:blood; D006801:Humans; D006820:Hyaluronic Acid / Q000032:analysis / Q000097:blood; D007403:Intervertebral Disc / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology*; D007405:Intervertebral Disc Displacement / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology*; D007633:Keratins / Q000032:analysis / Q000097:blood; D008297:Male; D064235:Matrilin Proteins; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011843:Radiculopathy / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology; D012585:Sciatica / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology*; D013997:Time Factors; D015854:Up-Regulation / Q000502:physiology
D015415:Biomarkers; D064236:Cartilage Oligomeric Matrix Protein; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D064235:Matrilin Proteins; C577553:TSP5 protein, human; D007633:Keratins; D006820:Hyaluronic Acid