Soluble receptor activator of nuclear factor κB ligand/osteoprotegerin ratio is increased in systemic lupus erythematosus patients.
BACKGROUND
Systemic lupus erythematosus (SLE) patients have lower bone mineral density and increased fracture risk when compared with healthy individuals, due to distinct factors and mechanisms. Bone remodeling is a tightly orchestrated process dependent on several factors, including the balance between receptor activator of nuclear factor κB ligand (RANKL) and osteoprotegerin (OPG). Our aim was to assess serum OPG and soluble RANKL (sRANKL) levels as well as sRANKL/OPG ratio in female SLE patients and compare it with female controls.


METHODS
We have evaluated 103 SLE patients and 114 healthy controls, all Caucasian females. All participants underwent a clinical and laboratory evaluation. sRANKL and OPG were quantified in serum by ELISA based methods. sRANKL, OPG and sRANKL/OPG ratio levels were compared between SLE patients and age, sex and race matched healthy controls. For SLE patients, a multivariate analysis was performed, to find the possible predictors of the changes in sRANKL, OPG and sRANKL/OPG ratio levels.


RESULTS
Although sRANKL levels did not differ between the two groups, serum OPG was lower in SLE patients (P < 0.001). This led to an increased sRANKL/OPG ratio (P = 0.010) in the patients' group.The multivariate analysis was performed considering age and other clinical and laboratorial potential confounders for these variations in the SLE patients group. We have showed that age (P = 0.001) and levels of anti-Sm antibodies (P = 0.016) were independent predictors of sRANKL/OPG ratio variations in SLE patients. No relationship with therapy or disease activity measured by SLEDAI2K was found.


CONCLUSIONS
These results are suggestive of increased osteoclastic stimuli driven by the SLE disease mechanisms.
Rheumatology Research Unit, Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Edifício Egas Moniz, Av, Prof, Egas Moniz, 1649-028 Lisboa, Portugal.
Diana
D
Carmona-Fernandes
Maria José
MJ
Santos
Inês Pedro
IP
Perpétuo
João Eurico
JE
Fonseca
Helena
H
Canhão
D000328:Adult; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000175:diagnosis; D008875:Middle Aged; D053244:Osteoprotegerin / Q000096:biosynthesis / Q000097:blood*; D011237:Predictive Value of Tests; D053245:RANK Ligand / Q000096:biosynthesis / Q000097:blood*; D015854:Up-Regulation / Q000502:physiology; D055815:Young Adult; D055517:snRNP Core Proteins / Q000096:biosynthesis / Q000097:blood
D015415:Biomarkers; D053244:Osteoprotegerin; D053245:RANK Ligand; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D055517:snRNP Core Proteins