Raman spectroscopy of fingernails: A novel tool for evaluation of bone quality?

Abstract

Abstract. Raman data from human fingernails has been analysed to determine if a relationship exists between spectral features and bone quality. Previous work demonstrated a relationship between the manually determined intensity of the disulphide peak (Bone Quality Test; BQT) and osteoporotic fracture. A computer program is now described that automates the BQT determination for large sample-sets. In this study the ability of the automated BQT to discriminate between fractures and controls was compared to that of bone mineral density (BMD) and biomarkers of bone remodelling. Females aged 18-67 years participated in the study (n = 159). Fingernails were analysed using Raman spectroscopy. Lumbar and Femoral BMD was measured by dual energy X-ray absorptiometry (DXA). Fasting venepuncture samples were analysed for osteocalcin and CTx (collagen C-telopeptides) by electrochemiluminescence. No correlation was found between the BQT and BMD or the biomarkers. The BQT and BMD were found to be equally accurate in identifying subjects with a history of fracture (p < 0.01) and both outperformed osteocalcin and CTx. It appears that keratin and collagen are related structural proteins that require disulphide bonding for stability. Therefore, these preliminary results suggest that Raman spectroscopy of keratin may have potential as a diagnostic tool for screening bone quality in large populations.

Raman spectral variation for human fingernails of postmenopausal women is dependent on fracture risk and osteoporosis status

“…A number of key features are apparent in this figure, and assignments of common bands in proteins are provided in Table . In keeping with previous findings, there is a change in the region where the disulphide mode is found, just above 500 cm −1 , with the mean nonfracture spectrum exhibiting a more intense feature centred around 507 cm −1 , while the mean fracture spectrum shows a broader flatter peak centred around 521 cm −1 . Table summarizes the different amino acid residue assignments that could be made against the full spectra.…”

“…In this study, only samples meeting the DXA score criteria at all three sites (femoral neck, wrist and vertebrae) measured were included in the respective group, to create a set of samples from participants with pervasive osteoporosis (standard osteoporosis definition as recommended by the WHO is that only one out of three sites needs to meet this threshold). Previous studies have suggested that the Raman changes to nails due to osteoporosis are subtle, so a more extreme set of criteria was applied to enhance the contrast between the two groups. Throughout the paper, ‘healthy’ is used to describe samples that were classified as ‘normal’ through DXA assessment, unless clarified otherwise or if used in a context unrelated to discussing samples.…”

“…Anecdotally, patients diagnosed with osteoporosis have reported loss of fingernail resilience with disease progression . Preliminary studies carried out by the authors have identified a link between the Raman spectra of human nail and both osteoporosis and fracture risk of the participant . The authors hypothesized that this link was due to the sensitivity of Raman spectroscopy in identifying differences in protein structure, thus facilitating the use of nail protein structure as a surrogate marker for bone protein structure.…”

Sex-related chemical differences in keratin from fingernail plates: a solid-state carbon-13 NMR study

“…Only rare reports have been devoted to the keratin structure in nails. It has been investigated in the context of some diseases [18][19][20][21][22][23][24][25] and aer chemical or physical modication. [26][27][28][29] In our opinion, the diagnosis of systemic diseases, based on the ngernail protein composition and structure, rstly requires a comprehensive examination of the keratin structure in healthy subjects.…”

Towards patient‐specific material modeling of trabecular bone post‐yield behavior

“…A number of characteristics define the mechanical properties of bone. The main characteristics, which vary across multiple scales , are often referred to as bone quality , such as geometry and architecture ; material composition, organization and cross‐links ; microdamage ; and bone turnover and remodeling . All these characteristics are highly influenced by individual external (e.g., adaptation to loading conditions) and internal (e.g., aging and disease) factors.…”