Bone-marrow lipid profiles from peripheral skeleton as potential biomarkers for osteoporosis: a 1H-MR Spectroscopy study.

Rationale and objectives: To characterize the lipidic profile of bone-marrow in the calcaneus and femoral-neck of healthy, osteopenicand osteoporotic women, by using Magnetic Resonance Spectroscopy (MRS) at 3T. The final goal was to identify specific metabolites with thepotential ability to discriminate between healthy, osteopenic and osteoporotic subjects.Materials and Methods: Sixty-two and thirty-three postmenopausal women recruited to investigate calcaneus and femoral neck, respectively,underwent a bone mineral density (BMD) measurement to be classified as healthy subjects (n=22), osteopenic (n=45) or osteoporotic (n=28)patients. MRS spectra were used to quantify and compare bone-marrow fat resonances between the three BMD groups. Between-group differences were tested usinga Welch ANOVA. Multiple comparisons were made with the Games-Howell correction. Relationship between pairs of variables were assessed withlinear correlation analysis. Reproducibility analysis was performed for all the lipid resonances in both sites.Results: The reproducibility was satisfactory. In femoral neck, methylene (L13), glycerol (L41, L43) and total lipid resonances were significantlylower in healthy as compared to osteoporotic subjects. On the other and, in calcaneus, L13/glycerol significantly discriminated between osteopenicand osteoporotic subjects while L13/(unsaturated lipid) discriminated between healthy and osteopenic group. However, the reproducibility ofboth unsaturated lipid and glycerol resonances were less optimal.Conclusions: MRS of bone-marrow lipid profiles from peripheral skeletal sites may be a promising tool for screening of large population toidentify individuals with or at risk for developing osteoporosis. Moreover, it provides information about the metabolic changes occurringin bone-marrow with the development of osteoporosis, which are skeletal site dependent.