The objective of the proposed bioengineering research partnership (BRP), located at the University of Florida, is to examine two key issues relevant to urolithiasis; 1) the effects of acidic biopolymers and lipid membranes on nucleation, growth and aggregation of calcium oxalate (CaOx) crystals in an artificial urinary environment; and 2) the injurious effects of a liquid-phase mineral precursor on tubular epithelial cells grown in culture. With regard to 1), many investigators have examined the promotory and inhibitory effects of acidic glycoproteins on crystal growth and aggregation. Our work differs in that a primary focus will be to investigate the relevance of a recently discovered polymer-induced liquid-precursor (PILP) process to pathological biomineralization. The PILP process generates non- equilibrium crystal morphologies which exhibit features similar to crystals found in kidney stones, such as for example, stratified spherulites. Mineral films and coatings are also deposited by the process, and repetitive depositions might lead to concentrically laminated structures, such as those commonly observed in composite stones. In addition, the interfacial aspects of this liquid-liquid phase separation process lead to a pronounced aggregation tendency of crystals. Lastly, we hypothesize that the presence of this cementatious mineral precursor in the urinary tract could influence the attachment and retention of crystals to renal epithelial cells; or the highly ionic precursor phase could cause cell injury or death, leading to the release of modulatory factors or membrane fragments, which could promote heterogeneous nucleation and/or aggregation of crystals. The proposed work consists of ten Specific Aims which fall under four topical areas: crystal-macromolecule, crystal- crystal, crystal-lipid, and crystal-cell interactions. The bioengineering techniques to be used include measurement of interparticle forces by Atomic Force Microscopy, measurement of long-range interactions between submicron CaOx particles and mimetic lipid membranes with an optical trap force transducer, and nucleation of crystals and PILP phase on mimetic lipid membranes using Langmuir monolayers. This 5-year project will enable us to assess the relevance of the PILP process to pathological calcification, as well as to perform a comparative analysis with the more traditional concepts pertaining to the role of lipids and acidic biopolymers in stone formation, and will contribute to the development of bioengineering techniques that are new to the field of stone research. The long-range clinical goal of this BRP is to provide a more effective means of diagnosis, treatment, and long-term prevention of renal calculi.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK059765-02
Application #
6517941
Study Section
Special Emphasis Panel (ZRG1-SSS-M (03))
Program Officer
Rasooly, Rebekah S
Project Start
2001-07-15
Project End
2005-06-30
Budget Start
2002-07-01
Budget End
2003-06-30
Support Year
2
Fiscal Year
2002
Total Cost
$465,629
Indirect Cost
Name
University of Florida
Department
Engineering (All Types)
Type
Schools of Engineering
DUNS #
073130411
City
Gainesville
State
FL
Country
United States
Zip Code
32611
Khan, Saeed R; Canales, Benjamin K (2009) Genetic basis of renal cellular dysfunction and the formation of kidney stones. Urol Res 37:169-80
Amos, Fairland F; Dai, Lijun; Kumar, Rajendra et al. (2009) Mechanism of formation of concentrically laminated spherules: implication to Randall's plaque and stone formation. Urol Res 37:11-7
Gower, Laurie B (2008) Biomimetic model systems for investigating the amorphous precursor pathway and its role in biomineralization. Chem Rev 108:4551-627
Amos, Fairland F; Sharbaugh, Denise M; Talham, Daniel R et al. (2007) Formation of single-crystalline aragonite tablets/films via an amorphous precursor. Langmuir 23:1988-94
Talham, Daniel R; Backov, Renal; Benitez, Isa O et al. (2006) Role of lipids in urinary stones: studies of calcium oxalate precipitation at phospholipid langmuir monolayers. Langmuir 22:2450-6
DiMasi, Elaine; Kwak, Seo-Young; Amos, Fairland F et al. (2006) Complementary control by additives of the kinetics of amorphous CaCO3 mineralization at an organic interface: in-situ synchrotron x-ray observations. Phys Rev Lett 97:045503
Khan, Saeed R (2006) Renal tubular damage/dysfunction: key to the formation of kidney stones. Urol Res 34:86-91
Habibzadegah-Tari, Pouran; Byer, Karen G; Khan, Saeed R (2006) Reactive oxygen species mediated calcium oxalate crystal-induced expression of MCP-1 in HK-2 cells. Urol Res 34:26-36
Byer, Karen; Khan, Saeed R (2005) Citrate provides protection against oxalate and calcium oxalate crystal induced oxidative damage to renal epithelium. J Urol 173:640-6
Habibzadegah-Tari, Pouran; Byer, Karen; Khan, Saeed R (2005) Oxalate induced expression of monocyte chemoattractant protein-1 (MCP-1) in HK-2 cells involves reactive oxygen species. Urol Res 33:440-7

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