Comparison of mineral quality and quantity in iliac crest biopsies from high- and low-turnover osteoporosis: an FT-IR microspectroscopic investigation

Abstract

Fourier-transform infrared microspectroscopy (FTIRM) allows analysis of mineral content, mineral crystal maturity and mineral composition at ∼10-μ spatial resolution. Previous FTIRM analyses comparing 4-μ thick sections from non-decalcified iliac crest biopsies from women with postmenopausal osteoporosis, as contrasted with iliac crest tissue from individuals without evidence of metabolic bone disease, demonstrated significant differences in average mineral content (decreased in osteoporosis) and mineral crystal size/perfection (increased in osteoporosis). More importantly, these parameters, which vary throughout the tissue in relation to the tissue age in healthy bone, showed no such variation in bone biopsies from patients with osteoporosis. The present study compares the spatial and temporal variation in mineral quantity and properties in trabecular bone in high-and low-turnover osteoporosis. Specifically, six biopsies from women (n=5) and one man with high-turnover osteoporosis (age range 39-77) and four women and two men with low turnover osteoporosis (age range 37-63) were compared to ten "normal" biopsies from three men and seven woman (age range: 27-69). "High turnover" was defined as the presence of increased resorptive surface, higher than normal numbers of osteoclasts and greater than or equal to normal osteoblastic activity. "Low turnover" was defined as lower than normal resorptive surface, decreased osteoclast number and less than normal osteoblastic activity. Comparing variations in FTIR-derived values for each of the parameters measured at the surfaces of the trabecular bone to the maximum value observed in multiple trabeculae from each person, the high-turnover samples showed little change in the mineral: matrix ratio, carbonate: amide I ratio, crystallinity and acid phosphate content. The lowturnover samples also showed little change in these parameters, but in contrast to the high-turnover samples, the low-turnover samples showed a slight increase in these parameters, indicative of retarded, but existent resorption and formation. These data indicate that FTIR microspectroscopy can provide quantitative information on mineral changes in osteoporosis that are consistent with proposed mechanisms of bone loss.

Towards new material biomarkers for fracture risk

“…When age matched, the mineral to organic ratio was not significantly different between the fracture and non-fracture group, although the values for the fracture group were lower. In contrast, previous studies have shown a decrease in the mineral to organic ratio in ovariectomized animal and osteoporotic human tissue [18,30,33,45,74], suggesting either a lower mineral content and/ or a greater collagen content. The consensus tends to be that in osteoporotic bone, a decrease in mineral content is observed [18,19], resulting in a reduction in mechanical strength [11].…”

“…In contrast other studies were unable to detect differences in the lattice parameters of osteoporotic bone [35]. As a further bone characteristic measured by FTIR, it has been reported that for osteoporotic tissues the mineral to organic ratio is lower than that of normal bone [18,30]. Thus in general, the literature contains several previous studies of bone physicochemical characteristics but these very often provide apparently conflicting findings and results.…”

Glucose-dependent insulinotropic polypeptide receptor deficiency leads to modifications of trabecular bone volume and quality in mice

“…Sequential raw spectra for each trabecula were averaged and the contribution of the embedding pMMA and water vapor were corrected prior to baseline correction. The evaluated IR spectral parameters were (1) mineral crystallinity, which reflects the apatite size and perfection, calculated as the ratio of the relative intensity of subbands at 1020 and 1030 cm − 1 of the phosphate band [27]; (2) collagen maturity, determined as the relative ratio of pyridinium trivalent (Pyr, mature collagen) to dehydrodihydroxylysinonorleucine divalent (deH-DHLNL, new collagen) collagen cross-links using their respective subbands located at 1660 cm − 1 and 1690 cm − 1 of the amide I peak [28] and (3) carbonates to phosphates ratio, which reflects the carbonate content in bone and determined by the ratio of integrated areas of the υ2 CO 3 2− region (850-890 cm −1 ) to the υ1, υ3 phosphate band (900-1200 cm −1 ) [29].…”

The degree of bone mineralization is maintained with single intravenous bisphosphonates in aged estrogen-deficient rats and is a strong predictor of bone strength

“…The ratio of high-density bone/ low-density bone had been reported to gradually increase with age [8]. In iliac crest bone biopsies from osteoporotic women, the degree of mineralization was decreased while the mineral crystal size and perfection was increased, as compared to the non-osteoporotic controls [9,10]. Treatment of osteoporotic women with the bisphosphonate alendronate, was reported to increase the mean degree of mineralization and the homogeneity of the mineral distribution in the cancellous bone of compared to placebo treated subjects [9,11].…”