(659d) Kidney Stone Growth Modification: Insights from First Principles Calculations

Authors: 
Taylor, M. G., University of Pittsburgh
Chung, J., University of Houston
Carnaval, I., University of Pittsburgh
Rimer, J. D., University of Houston
Mpourmpakis, G., University of Pittsburgh

Nearly 1 in 11 Americans will develop kidney stones during their lives1. Kidney stones are largely composed of calcium oxalate monohydrate (COM) crystals and develop as a result of heightened concentrations of oxalate in urine 2. Previous work 2 has identified citric acid (CA) as an effective COM crystal growth modifier. Recently, Dr. Rimer’s group at the University of Houston has shown that hydroxycitric acid (HCA) is a highly effective COM crystal growth modifier with notably different growth modification properties than CA. HCA is a molecule with the same structure as CA except for an additional hydroxyl functional group. In this work we use first-principles calculations to elucidate the growth modification mechanisms of CA and HCA at the molecular level. Ab-initio pKa calculations3demonstrate that HCA exhibits lower deprotonation constants than CA due to increased intramolecular hydrogen bonding. Accelerated Density Functional Theory calculations (accounting for solvent effects) revealed that HCA exhibits increased folding capability and binding affinity to both calcium ions and oxalate surfaces than CA. Most importantly this work introduces concepts that may be used in the rational design of effective kidney stone growth modifiers.

References

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  2. Qiu, S. R., Wierzbicki, a., Orme, C. a., Cody, a. M., Hoyer, J. R., Nancollas, G. H., Zepeda, S., and De Yoreo, J. J. Proceedings of the National Academy of Sciences of the United States of America 101(7), 1811–1815 (2004).
  3. Feng, S., Bagia, C., and Mpourmpakis, G. Journal of Physical Chemistry A 117, 5211–5219 (2013).