UC San Diego

Many previous studies have shown that artery calcification is linked to increased bone loss. Other studies have suggested that an agent released from bone causes artery calcification by traveling through blood. Previous studies have also shown that serum has crystal formation activity, and our goal is to develop a quantitative assay for this activity. Our long term goal is to determine if serum crystal forming activity is elevated in patients with increased bone loss.

In previous studies, Erin Hourigan developed a method to monitor serum crystal formation activity by diluting serum 50 fold with 2mM Calcium and Phosphate at 37C and pH 7.4. Hourigan’s assay measured Calcium decline at multiple time-points, and was very labor intensive. In contrast, my assay allows the Calcium decline to go to completion and then directly monitors serum’s crystal formation activity by counting the number of crystals present in solution in addition to measuring Calcium decline in solution.

The number of crystals counted by our assay were significantly higher (p<.0005) in human neonates than in human adults, which may be due to the fact that the rate of bone turnover is significantly higher in newborns than in adults, causing a rise in neonate’s serum crystal formation activity. We found that crystals counted by our assay probably originate from the growth of much smaller crystals already present in serum and are not formed by a serum catalyst. This assay is the first demonstration that human serum has crystals that can be directly counted.