Use of FTIR Spectroscopic Imaging to Identify Parameters Associated With Fragility Fracture

Abstract

BMD does not entirely explain an individual's risk of fracture. The purpose of this study was to assess whether specific differences in spatially resolved bone composition also contribute to fracture risk. These differences were assessed using Fourier transform infrared spectroscopic imaging (FTIRI) and analyzed through multiple logistic regression. Models were constructed to determine whether FTIRI measured parameters describing mineral content, mineral crystal size and perfection, and collagen maturity were associated with fracture. Cortical and cancellous bone were independently evaluated in iliac crest biopsies from 54 women (32 with fractures, 22 without) who had significantly different spine but not hip BMDs and ranged in age from 30 to 83 yr. The parameters that were significantly associated with fracture in the model were cortical and cancellous collagen maturity (increased with increased fracture risk), cortical mineral/ matrix ratio (higher with increased fracture risk), and cancellous crystallinity (increased with increased fracture risk). As expected, because of its correlation with cortical but not cancellous bone density, hip BMD was significantly associated with fracture risk in the cortical but not the cancellous model. This research suggests that additional parameters associated with fracture risk should be targeted for therapies for osteoporosis.

Atypical fracture with long-term bisphosphonate therapy is associated with altered cortical composition and reduced fracture resistance

“…Cortical bone from patients with atypical fractures had greater tissue mineral content as assessed by Raman and FTIR imaging and greater collagen maturity as assessed by FTIR imaging, as well as greater hardness, relative to that from patients without fractures, all of which are expected to diminish the ductility and hence decrease intrinsic toughness in bone (28). Consistent with these results, increased FTIR mineralization and collagen maturity are associated with increased fracture risk (29).…”

Towards new material biomarkers for fracture risk

“…There is clear evidence of significant differences in the physicochemical characteristics of bone mineral from different sample sites. For example, Gourion-Arsiquaud et al reported greater cortical mineral/organic and trabecular crystallinity values associated with increased fracture risk when iliac crest specimens were analysed [32]. However, more recently, when investigating material properties of femoral neck specimens, a decrease in the mineral: organic ratio for both cortical and trabecular fractured bone was observed whilst no change in crystallinity was reported [33] by the same research group.…”

Infrared spectroscopy indicates altered bone turnover and remodeling activity in renal osteodystrophy

“…Previously, FTIRI has been employed to study osteoporotic bone (17,19,27) or bone from patients with fragility fractures, (15) as well as bone from patients with ostemalacia. (18) However, to our knowledge, no previous studies have employed FTIRI to investigate bone from patients with ROD.…”

“…Recent studies have indicated that the increased fracture risk in other metabolic bone diseases such as osteoporosis not only may follow from the low bone mass and distorted bone structure but also may be due to altered composition of the bone tissue. (14)(15)(16)(17) The ability of Fourier transform infrared spectroscopic imaging (FTIRI) to characterize changes in the mineral or collagen phase (17)(18)(19)(20) The advantage of the technique is its ability to image and measure the spatial composition of the tissue. FTIRI can be used to identify samples, to characterize unknown materials, and also to determine the quality or consistency of a sample.…”