Assessment Of Multiple Analytes In Women With Osteoporosis And Depression

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Bone loss in women pre- and post-menopause is a serious clinical condition affecting a reasonably large proportion of the public. Depression is a compounding condition that has been shown to accentuate pathways leading to bone loss and suggesting a mind-body connection. The POWER study conducted at the NIH Clinical Center is designed to study the interactions of depression and severity of osteoporosis in pre-menopausal women. The Ultramicro Analytical Immunochemistry group, NIBIB has undertaken to develop a panel of analytical techniques (recycling immunoaffinity chromatography RIC; immunoaffinity microarrays; immunoaffinity capillary electrophoresis ICE) to study a number of different systemic pathways that possibly may be involved in the connection between osteoporosis and depression. Cohorts of both normal and depressed age-matched women have been recruited into the double-blinded study. Codes were broken only after the analyses. Samples were taken on three occasions, during which 24 one-hour samples were taken and analyzed for 45 different analytes. Although the sample analyses have now been successfully completed, the data analysis is still in progress, due to the extremely large number of data points generated. Preliminary examination of the data has indicated circadian rhythms for many of the different cytokines and growth factors measured. The data also indicate that the depressed individuals can be classified into two groups according to their analyte patterns. Preliminary analysis has indicated a strong correlation between the presence of pain-associated neuropeptides and changes in bone density. Recent studies have focused on the development of techniques for measuring immune-stress biomarkers using minimally or non-invasive procedures. A commercially available sweat patch has been studied as a non-invasive 24-hour collection device. The patch, essentially a large adhesive bandage, is applied to the subjects skin and left in place for 24 hours during normal activities. The patch is removed and the collected sweat extracted. After considerable experimentation, it was found that a vacuum extraction device provided the most efficient means to recover the desired body fluid. Plasma samples were also drawn from the test subjects in order to compare analyte concentrations. The initial studies have shown that sweat recovery compares well with plasma concentrations and that a panel of neuro-immune markers of stress and inflammation can easily be measured using the analytical techniques already in place.