Romatoid artritli hastalarda RANKL, osteoprotegerin ve katepsin-K düzeylerinin kemik mineral yoğunluğu arasında ilişki

The relationship between bone mineral density and levels of RANKL, osteoprotegerin and cathepsin-K in patients with rheumatoid arthritis

Gökhan ÇAKIRCA,NURİYE METE,Ibrahim BATMAZ,Mustafa Akif SARIYILDIZ,Mehmet Ali ULU,Levent YAZMALAR,TAHSİN ÇELEPKOLU,Remzi ÇEVİK

Abstract

Objectives: The aim of this study was to evaluate the levels of osteoprotegerin (OPG), nuclear factor kappa B receptor activator ligand (RANKL), cathepsin K in patients with rheumatoid arthritis (RA) and the relation between these parameters and bone mineral density (BMD). Materials and methods: Totally 90 cases including 30 postmenopausal and healthy women, 30 with postmeno-pausal osteoporosis and 30 with postmenopause RA were enrolled in the study. The serum RANKL, OPG and cathepsin K were measured by ELISA method. Results: The levels of serum RANKL and OPG in the pa- tients with postmenopausal RA were found significantly higher compared to the postmenopausal healthy women whereas the rate of serum OPG/RANKL was found sig- nificantly lower. In addition, the rate of OPG and OPG/ RANKL were significantly lower in patients with post- menopausal RA compared to the postmenopausal osteo- porosis, whereas the level of serum RANKL was signifi- cantly higher. Positive correlation was detected between bone densities of lumbar spine (LS), femur neck (FN) and the rate of OPG/RANKL in patients with postmenopausal RA. Also negative correlation was detected between LS and FN bone densities and RANKL levels. Conclusions: The system of RANKL/RANK/OPG may have a role in osteoporosis and RA pathogenesis and the rate of OPG/RANKL might be a significant determiner of bone density.

Özet

Amaç: Bu çalışmanın amacı Romatoid Artrit’li (RA) hastalarda Osteoprotegerin (OPG), Nükleer faktör kappa B reseptör aktivatörü ligandı (RANKL), katepsin-K düzeylerini ve ayrıca bu parametrelerin kemik mineral yoğunluğu (BMD) ile ilişkisini araştırmaktır. Gereç ve yöntem: Çalışmaya postmenopozal sağlıklı (n=30), postmenopozal osteoporozlu (n=30) ve postmenopoz RA’lı (n=30) toplam 90 olgu alındı. Serum RANKL, OPG ve katepsin-K ELİSA yöntemiyle çalışıldı. Bulgular: Postmenopozal RA’ lı hastalarda serum RANKL ve OPG seviyeleri postmenopozal sağlıklı kontrollere kıyasla anlamlı yüksekken, serum OPG/RANKL oranı anlamlı düşük bulundu. Bununla birlikte postmenopozal RA’lı hastalarda, postmenopozal osteoporozlu hastalara göre serum OPG ve OPG/RANKL oranı anlamlı düşük iken, serum RANKL seviyesi anlamlı yüksekti. Postmenopozal RA’lı hastalarda lomber spine (LS) ve femur neck (FN) kemik mineral dansiteleri (BMD) ile OPG/RANKL oranı arasında pozitif korelasyon saptanırken; RANKL düzeyleri ile negatif korelasyon bulundu. Sonuç: RANKL/RANK/OPG sistemi osteoporoz ve RA patogenezinde rol alabilmektedir ve OPG/RANKL oranı kemik dansitesinin önemli bir belirleyicisi olabilir.