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AB0914 Bone mass and MMP3/TIMP in ankylosing spondylitis
  1. V. Dhir1,
  2. R. Srivastava2,
  3. A. Aggarwal2
  1. 1Internal Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, Chandigarh
  2. 2Clinical Immunology, Sanjay Gandhi Postgraduate institute of Medical Sciences, Lucknow, India

Abstract

Background There is some data to suggest that bone mineral density is lower in patients with ankylosing spondylitis. The mechanism could be increased matrix metalloproteinase 3 (MMP-3) activity and/or lower inhibitor levels (TIMP).

Objectives To compare bone mineral density of ankylosing spondylitis patients with published Indian standards. Also to compare MMP-3/TIMP ratio with controls.

Methods Patients who fulfilled modified New York criteria and gave consent were recruited. Bone mineral density was done using a Hologic DXA system. These were compared to published Indian standards (ICMR) of healthy young individuals (1). Levels of MMP-3 and TIMP in serum were determined using ELISA in both patients as well as 20 healthy controls (RnD Duo Set). Statistical analysis was done by using student t test for difference in means, correlation by pearsons correlation. Values are in mean (±SD).

Results 48 patients (M: F=46:2) of ankylosing spondylitis with age 33.7 (±10.1) years were enrolled. Disease duration was 11.2 (±6.0) years and duration of diagnosis 3.3 (±4.1) years. Mean BASDAI was 3.5 (±2.0), BASFI 3.2 (±2.3) and BASMI 2.3 (±2.3). Bone mineral density in patients compared to published Indian standards was not different in the spine (0.907±0.39, 0.976±0.105g/cm2, p=0.34) or forearm (0.604±0.063, 0.611±0.052 g/cm2, p=0.35) but was lower in the hip (0.846±0.130, 0.988±0.131 g/cm2, p=0.02). In patients as compared to controls, both serum MMP-3 (90.5±95.8, 55.9±37.1 ng/ml, p=0.04) and TIMP levels were higher (622.8±551.1, 296.5±114.2 ng/ml, p<0.001). However, there was no difference in the MMP-3/TIMP ratio (0.20±0.22, 0.20±0.14, p=0.95). Among patients, there was a negative correlation between the BMD of the hip and MMP/TIMP (r=-0.29, p=0.04) and BMD of forearm with MMP3/TIMP (r=-0.43, p=0.002). But there was a positive correlation with the BMD spine (r=0.41, p=0.003). There was no significant correlation between the ESR or BASDAI with MMP-3, TIMP or MMP-3/TIMP ratio.

Conclusions There is mild reduction of bone mineral density only in the hip in patients of ankylosing spondylitis compared to published Indian standards. Although both MMP-3 and TIMP are higher in patients, there is no difference in the MMP3/TIMP ratio compared to controls.

  1. New Delhi: ICMR: Published by Director General; 2010. Population based reference standards of Peak Bone Mineral Density of Indian males and females – an ICMR multi-center task force study; pp. 1–24.

Disclosure of Interest None Declared

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