Raman spectroscopy of the human nail: a potential tool for evaluating bone health?

Area of Science:

• Biochemistry
• Biophysics
• Orthopedics

Background:

• Dual X-ray absorptiometry (DXA) is the standard for osteoporosis diagnosis but doesn't fully capture fracture risk.
• Osteoporosis affects both bone's mineral and protein phases, yet only the mineral phase is routinely assessed.
• There's a need for clinical methods to evaluate the protein matrix health in bone.

Purpose of the Study:

• To investigate if Raman spectroscopy of fingernails can assess protein structural integrity.
• To explore the correlation between nail disulphide content and bone health indicators, including fracture history.

Main Methods:

• Raman spectroscopy was used to measure disulphide (S-S) bond content in fingernails from 169 women.
• Bone mineral density (BMD) was measured using DXA.
• Statistical analyses compared disulphide content and BMD with fracture history and menopausal status.

Main Results:

• Nail disulphide content decreased with age and was slightly higher in pre-menopausal women.
• Significantly lower disulphide content was found in women with a history of osteoporotic fracture (P=0.025).
• Nail disulphide content and BMD were comparable predictors of fracture status.

Conclusions:

• Non-invasive measurement of nail disulphide content may serve as an indicator of bone protein health.
• This method shows potential for assessing fracture risk, complementing DXA measurements.
• Changes in structural proteins like keratin in nails might correlate with bone collagen changes relevant to fracture risk.