The Relationship Between Bone Mass with Osteocalcin and Bone Marrow Lipids in Type 2 Diabetes Mellitus

Presentation Number: SAT 307
Date of Presentation: April 1st, 2017

Iana Mizumukai de Araujo1, Carlos Ernesto Garrido Salmon2, Marcello Henrique Nogueira-Barbosa3 and Francisco J A de Paula*4
1Ribeirao Preto Medical School, USP, Ribeirao Preto, Brazil, 2Ribeirão Preto Medical School, USP, Ribeirao Preto, Brazil, 3Ribeirão Preto Medical School, USP, Ribeirao Preto, Brazil, 4Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil

Abstract

Introduction: The interaction between bone and adipose tissue is complex and it is still to be delineated. Recent studies call attention that not only marrow adipose tissue quantity but also lipids composition impacts bone health. Paradoxically, bone fragility in type 2 diabetes mellitus (T2DM) emerges in individuals showing high bone mass combined with low bone turnover, namely decreased serum levels of biochemical bone markers. The interplay between lipids composition and osteocalcin still is to be studied.

Objective:To investigate the relationship between bone marrow lipid fractions with bone mass and bone turnover markers in T2DM and obesity.

Material and Methods: The study group comprised 19 controls (6M and 13F), 21 (7M and 14F) obese and 22 T2DM subjects (11M and 11F). Magnetic resonance 1H spectroscopy (MRS) was used to assess BMAT and lipid fractions [saturated (SL) and unsaturated lipids (UL)] in the third lumbar vertebra (L3). DXA was used to measure bone mass in lumbar spine (L1-L4 BMD). Osteocalcin (OC) and CTX were assessed by ELISA immunoassay.

Results:The 3 groups were well matched by age (C: 54.8±7.2; O: 52.5±11.8; T2DM: 54.2±9.6 years) and height (C: 1.67±0.1; O: 1.62±0.1; T2DM: 1.63±0.1m). Weight was lower in C than in O and T2DM (C: 67.9±8.2; O: 83.1±18.7; T2DM: 87.1±16.9 Kg), as well as BMI (C: 24.1±1.6; O: 31.3±3; T2DM: 33±7 Kg/m²) (p<0.05). The mean values of L1-L4 BMD in T2DM was higher than in C (C: 0.952±0.109; O: 0.971±0.166; T2DM: 1.061±0.140g/cm²; p<0.05). BMAT (C: 35.2±9.5; O:32.3±6.1; T2DM: 36.4±8.5%); SL (C: 29.3±7%; O: 27.2±5; T2DM: 28.3±6.87) and UL (C: 3±1.2; O: 2.8±1.5; T2DM: 2.7±0.8%) values were similar in the 3 groups. The serum levels of OC were slightly lower in T2DM (C: 9.6±4; O: 9.5±7; T2DM: 6.8±2.8ng/mL), while CTX was lower in T2DM than in C group (CTX= C: 0.36±0.15; O: 0.35±0.14; T2DM: 0.25±0.1 ng/mL, p<0.05). As expected there was a negative correlation between BMAT and L1-L4 BMD (r=-0.25;p<0.05). Also, there was a positive correlation between OC and CTX (r=0.65;p<0.05). The circulatory levels of OC and was negatively correlated with L1-L4 BMD (r=-0.38; p<0.05). There was a positive correlation between OC and SL (r=0.29;p<0.05).

Conclusion:This study highlights interesting aspects concerning the osteometabolic profile in T2DM, which potentially can contribute to fracture susceptibility in this condition. Bone markers are not only low in T2DM, OC is both negatively correlated with bone mass as well as positively correlated with the bone marrow saturated lipids. These results indicate that high bone mass in T2DM is closely linked to decreased rate of bone remodeling and this process can be influenced by the lipid profile in bone marrow microenvironment.

 

Nothing to Disclose: IMD, CEGS, MHN, FJAD