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Welzel C, König U, Jannasch A, Matschke K, Tugtekin SM, Dittfeld C, Steiner G. Infrared Spectroscopic Verification of a α-Helical Collagen Structure in Glutaraldehyde-Free Crosslinked Bovine Pericardium for Cardiac Implants. LIFE (BASEL, SWITZERLAND) 2022; 12:life12122035. [PMID: 36556400 PMCID: PMC9785276 DOI: 10.3390/life12122035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/23/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022]
Abstract
The degeneration of heart valve bioprostheses due to calcification processes is caused by the intercalation of calciumhydroxyapatite in pericardium collagen bundles. Variations of the protein secondary structure of biomaterials according to preparation are relevant for this mineralization process and thus the structural characterization of innovative bioprostheses materials is of great importance. The gold standard for prostheses preparation is glutaraldehyde (GA)-fixation of bovine pericardium that adversely promotes calcification. The novel GA-free SULEEI-treatment of bovine pericardium includes decellularization, UV-crosslinking, and electron beam sterilization. The aim of this study is the structural characterization of SULEEI-treated and GA-fixed bovine pericardium. IR spectroscopic imaging combined with multivariate data and curve fit analysis was applied to investigate the amide I and amide II regions of SULEEI-treated and GA-fixed samples. The spectroscopic images of GA-fixed pericardial tissue exhibited a generally high content of amine groups and side chains providing nucleation points for calcification processes. In contrast, in SULEEI-treated tissue, the typical α-helical structure was retained and was supposed to be less prone to deterioration.
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Affiliation(s)
- Cindy Welzel
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, 01307 Dresden, Germany
- Correspondence:
| | - Ulla König
- Department of Medical and Biotechnological Applications, Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology, 01277 Dresden, Germany
| | - Anett Jannasch
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, 01307 Dresden, Germany
| | - Klaus Matschke
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, 01307 Dresden, Germany
| | - Sems-Malte Tugtekin
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, 01307 Dresden, Germany
| | - Claudia Dittfeld
- Department of Cardiac Surgery, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Heart Centre Dresden, 01307 Dresden, Germany
| | - Gerald Steiner
- Department of Anaesthesiology and Critical Care Medicine, Clinical Sensoring and Monitoring, Faculty of Medicine, Technische Universität Dresden, 01307 Dresden, Germany
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Bogdanova M, Zabirnyk A, Malashicheva A, Semenova D, Kvitting JPE, Kaljusto ML, Perez MDM, Kostareva A, Stensløkken KO, Sullivan GJ, Rutkovskiy A, Vaage J. Models and Techniques to Study Aortic Valve Calcification in Vitro, ex Vivo and in Vivo. An Overview. Front Pharmacol 2022; 13:835825. [PMID: 35721220 PMCID: PMC9203042 DOI: 10.3389/fphar.2022.835825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 04/29/2022] [Indexed: 11/23/2022] Open
Abstract
Aortic valve stenosis secondary to aortic valve calcification is the most common valve disease in the Western world. Calcification is a result of pathological proliferation and osteogenic differentiation of resident valve interstitial cells. To develop non-surgical treatments, the molecular and cellular mechanisms of pathological calcification must be revealed. In the current overview, we present methods for evaluation of calcification in different ex vivo, in vitro and in vivo situations including imaging in patients. The latter include echocardiography, scanning with computed tomography and magnetic resonance imaging. Particular emphasis is on translational studies of calcific aortic valve stenosis with a special focus on cell culture using human primary cell cultures. Such models are widely used and suitable for screening of drugs against calcification. Animal models are presented, but there is no animal model that faithfully mimics human calcific aortic valve disease. A model of experimentally induced calcification in whole porcine aortic valve leaflets ex vivo is also included. Finally, miscellaneous methods and aspects of aortic valve calcification, such as, for instance, biomarkers are presented.
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Affiliation(s)
- Maria Bogdanova
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Arsenii Zabirnyk
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Research and Development, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway
| | - Anna Malashicheva
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Daria Semenova
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, Russia
| | | | - Mari-Liis Kaljusto
- Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
| | | | - Anna Kostareva
- Almazov National Medical Research Centre, Saint Petersburg, Russia.,Department of Woman and Children Health, Karolinska Institute, Stockholm, Sweden
| | - Kåre-Olav Stensløkken
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Gareth J Sullivan
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Norwegian Center for Stem Cell Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,Institute of Immunology, Oslo University Hospital, Oslo, Norway.,Hybrid Technology Hub - Centre of Excellence, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Pediatric Research, Oslo University Hospital, Oslo, Norway
| | - Arkady Rutkovskiy
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Pulmonary Diseases, Oslo University Hospital, Oslo, Norway
| | - Jarle Vaage
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Research and Development, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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Parashar A, Gourgas O, Lau K, Li J, Muiznieks L, Sharpe S, Davis E, Cerruti M, Murshed M. Elastin calcification in in vitro models and its prevention by MGP's N-terminal peptide. J Struct Biol 2021; 213:107637. [PMID: 33059036 DOI: 10.1016/j.jsb.2020.107637] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 10/01/2020] [Accepted: 10/03/2020] [Indexed: 01/17/2023]
Abstract
Medial calcification has been associated with diabetes, chronic kidney disease, and genetic disorders like pseudoxanthoma elasticum. Recently, we showed that genetic reduction of arterial elastin content reduces the severity of medial calcification in matrix Gla protein (MGP)-deficient and Eln haploinsufficient Mgp-/-;Eln+/- mice. This study suggests that there might be a direct effect of elastin amount on medial calcification. We studied this using novel in vitro systems, which are based on elastin or elastin-like polypeptides. We first examined the mineral deposition properties of a transfected pigmented epithelial cell line that expresses elastin and other elastic lamina proteins. When grown in inorganic phosphate-supplemented medium, these cells deposited calcium phosphate minerals, which could be prevented by an N'-terminal peptide of MGP (m3pS) carrying phosphorylated serine residues. We next confirmed these findings using a cell-free elastin-like polypeptide (ELP3) scaffold, where the peptide prevented mineral maturation. Overall, this work describes a novel cell culture model for elastocalcinosis and examines the inhibition of mineral deposition by the m3pS peptide in this and a cell-free elastin-based scaffold. Our study provides strong evidence suggesting the critical functional roles of MGP's phosphorylated serine residues in the prevention of elastin calcification and proposes a possible mechanism of their action.
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Affiliation(s)
- Abhinav Parashar
- Faculty of Dentistry, McGill University, Montreal, Québec, Canada
| | - Ophélie Gourgas
- Department of Medicine, McGill University, Montreal, Québec, Canada
| | - Kirk Lau
- Materials Engineering, McGill University, Montreal, Québec, Canada
| | - Jingjing Li
- Department of Medicine, McGill University, Montreal, Québec, Canada
| | - Lisa Muiznieks
- Molecular Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Simon Sharpe
- Molecular Medicine, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Elaine Davis
- Department of Anatomy and Cell Biology, McGill University, Montreal, Québec, Canada
| | - Marta Cerruti
- Materials Engineering, McGill University, Montreal, Québec, Canada
| | - Monzur Murshed
- Faculty of Dentistry, McGill University, Montreal, Québec, Canada; Department of Medicine, McGill University, Montreal, Québec, Canada; Shriners Hospital for Children, Montreal, Quebec, Canada.
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Boraldi F, Lofaro FD, Quaglino D. Apoptosis in the Extraosseous Calcification Process. Cells 2021; 10:cells10010131. [PMID: 33445441 PMCID: PMC7827519 DOI: 10.3390/cells10010131] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/07/2021] [Accepted: 01/10/2021] [Indexed: 12/13/2022] Open
Abstract
Extraosseous calcification is a pathologic mineralization process occurring in soft connective tissues (e.g., skin, vessels, tendons, and cartilage). It can take place on a genetic basis or as a consequence of acquired chronic diseases. In this last case, the etiology is multifactorial, including both extra- and intracellular mechanisms, such as the formation of membrane vesicles (e.g., matrix vesicles and apoptotic bodies), mitochondrial alterations, and oxidative stress. This review is an overview of extraosseous calcification mechanisms focusing on the relationships between apoptosis and mineralization in cartilage and vascular tissues, as these are the two tissues mostly affected by a number of age-related diseases having a progressively increased impact in Western Countries.
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Affiliation(s)
- Federica Boraldi
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy; (F.D.L.); (D.Q.)
- Correspondence:
| | - Francesco Demetrio Lofaro
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy; (F.D.L.); (D.Q.)
| | - Daniela Quaglino
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy; (F.D.L.); (D.Q.)
- Interuniversity Consortium for Biotechnologies (CIB), Italy
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Gourgas O, Khan K, Schwertani A, Cerruti M. Differences in mineral composition and morphology between men and women in aortic valve calcification. Acta Biomater 2020; 106:342-350. [PMID: 32092430 DOI: 10.1016/j.actbio.2020.02.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 01/31/2020] [Accepted: 02/18/2020] [Indexed: 01/02/2023]
Abstract
Aortic valve calcification leads to the deposition of calcium phosphate minerals in the extracellular matrix of the aortic valve leaflets. The mineral deposits can severely narrow the opening of the aortic valve, leading to aortic stenosis. There are no therapies to halt or slow down disease progression and the mechanisms governing aortic valve calcification are still poorly understood. Recently, several studies have shown that for the same aortic stenosis severity, women present significantly lower calcification loads than men. The cause of this sex-related difference is unknown. To understand this difference, we analyzed mineral deposits from surgically excised calcified human aortic valves with different material characterization techniques. We find profound differences in mineral composition and morphology between sexes, which strongly suggest that minerals form slower in women than in men and follow a different mineralization pathway. This finding paves the way for new approaches specifically geared towards men or women in the diagnosis and treatment of aortic valve calcification. STATEMENT OF SIGNIFICANCE: Aortic valve calcification is a health disorder with increasing prevalence and high morbidity and mortality. Currently there is no approved effective treatment; the only available therapeutic option is invasive valve replacement, to which not all patients are suited. The main reason for such lack of treatment options is our lack of understanding of the calcification mechanism. In this study, we show profound differences in mineral composition and morphology between sexes, suggesting that aortic valve calcification follows different mineralization pathways in men and women. These findings pave the way for new approaches specifically geared towards men or women in the diagnosis and treatment of aortic valve calcification.
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Gourgas O, Muiznieks LD, Bello DG, Nanci A, Sharpe S, Cerruti M. Cross-Linked Elastin-like Polypeptide Membranes as a Model for Medial Arterial Calcification. Biomacromolecules 2019; 20:2625-2636. [DOI: 10.1021/acs.biomac.9b00417] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Ophélie Gourgas
- Department of Mining and Materials Engineering, McGill University, Montreal, Quebec H3A 0C5, Canada
| | - Lisa D. Muiznieks
- Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Dainelys Guadarrama Bello
- Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montreal, Quebec H3C 3J7, Canada
| | - Antonio Nanci
- Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montreal, Quebec H3C 3J7, Canada
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Université de Montréal, Montreal, Quebec H3C 3J7, Canada
| | - Simon Sharpe
- Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Marta Cerruti
- Department of Mining and Materials Engineering, McGill University, Montreal, Quebec H3A 0C5, Canada
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Richards JM, Kunitake JA, Hunt HB, Wnorowski AN, Lin DW, Boskey AL, Donnelly E, Estroff LA, Butcher JT. Crystallinity of hydroxyapatite drives myofibroblastic activation and calcification in aortic valves. Acta Biomater 2018; 71:24-36. [PMID: 29505892 DOI: 10.1016/j.actbio.2018.02.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 02/15/2018] [Accepted: 02/22/2018] [Indexed: 12/30/2022]
Abstract
Calcific aortic valve disease (CAVD) is an inexorably degenerative pathology characterized by progressive calcific lesion formation on the valve leaflets. The interaction of valvular cells in advanced lesion environments is not well understood yet highly relevant as clinically detectable CAVD exhibits calcifications composed of non-stoichiometric hydroxyapatite (HA). In this study, Fourier transform infrared spectroscopic imaging was used to spatially analyze mineral properties as a function of disease progression. Crystallinity (size and perfection) increased with increased valve calcification. To study the relationship between crystallinity and cellular behavior in CAVD, valve cells were seeded into 3D mineral-rich collagen gels containing synthetic HA particles, which had varying crystallinities. Lower crystallinity HA drove myofibroblastic activation in both valve interstitial and endothelial cells, as well as osteoblastic differentiation in interstitial cells. Additionally, calcium accumulation within gels depended on crystallinity, and apoptosis was insufficient to explain differences in HA-driven cellular activity. The protective nature of endothelial cells against interstitial cell activation and calcium accumulation was completely inhibited in the presence of less crystalline HA particles. Elucidating valve cellular behavior post-calcification is of vital importance to better predict and treat clinical pathogenesis, and mineral-containing hydrogel models provide a unique 3D platform to evaluate valve cell responses to a later stage of valve disease. STATEMENT OF SIGNIFICANCE We implement a 3D in vitro platform with embedded hydroxyapatite (HA) nanoparticles to investigate the interaction between valve interstitial cells, valve endothelial cells, and a mineral-rich extracellular environment. HA nanoparticles were synthesized based on analysis of the mineral properties of calcific regions of diseased human aortic valves. Our findings indicate that crystallinity of HA drives activation and differentiation in interstitial and endothelial cells. We also show that a mineralized environment blocks endothelial protection against interstitial cell calcification. Our HA-containing hydrogel model provides a unique 3D platform to evaluate valve cell responses to a mineralized ECM. This study additionally lays the groundwork to capture the diversity of mineral properties in calcified valves, and link these properties to progression of the disease.
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Gourgas O, Marulanda J, Zhang P, Murshed M, Cerruti M. Multidisciplinary Approach to Understand Medial Arterial Calcification. Arterioscler Thromb Vasc Biol 2018; 38:363-372. [PMID: 29217507 DOI: 10.1161/atvbaha.117.309808] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 11/22/2017] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Vascular calcification significantly increases morbidity in life-threatening diseases, and no treatments are available because of lack of understanding of the underlying molecular mechanism. Here, we study the physicochemical details of mineral nucleation and growth in an animal model that faithfully recapitulates medial arterial calcification in humans, to understand how pathological calcification is initiated on the vascular extracellular matrix. APPROACH AND RESULTS MGP (matrix Gla protein) is a potent mineralization inhibitor. We study the evolution of medial calcification in MGP-deficient mice over the course of 5 weeks using a combination of material science techniques and find that mineral composition and crystallinity evolve over time and space. We show that calcium is adsorbed first and then amorphous calcium phosphate and octacalcium phosphate forms, which then transform into hydroxyapatite and carbonated apatite. These events are repeated after each nucleation event, providing a snapshot of the overall mineral evolution at each time point analyzed. CONCLUSIONS Our results show that an interdisciplinary approach combining animal models and materials science can provide insights into the mechanism of vascular calcification and suggest the importance of analyzing mineral phases, rather than just overall mineralization extent, to diagnose and possibly prevent disease development.
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Affiliation(s)
- Ophélie Gourgas
- From the Materials Engineering (O.G., P.Z., M.C.), Faculty of Dentistry (J.M., M.M.), Department of Medicine (M.M.), and Shriners Hospital for Children (M.M.), McGill University, Montreal, Quebec, Canada
| | - Juliana Marulanda
- From the Materials Engineering (O.G., P.Z., M.C.), Faculty of Dentistry (J.M., M.M.), Department of Medicine (M.M.), and Shriners Hospital for Children (M.M.), McGill University, Montreal, Quebec, Canada
| | - Peng Zhang
- From the Materials Engineering (O.G., P.Z., M.C.), Faculty of Dentistry (J.M., M.M.), Department of Medicine (M.M.), and Shriners Hospital for Children (M.M.), McGill University, Montreal, Quebec, Canada
| | - Monzur Murshed
- From the Materials Engineering (O.G., P.Z., M.C.), Faculty of Dentistry (J.M., M.M.), Department of Medicine (M.M.), and Shriners Hospital for Children (M.M.), McGill University, Montreal, Quebec, Canada
| | - Marta Cerruti
- From the Materials Engineering (O.G., P.Z., M.C.), Faculty of Dentistry (J.M., M.M.), Department of Medicine (M.M.), and Shriners Hospital for Children (M.M.), McGill University, Montreal, Quebec, Canada.
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Inertial particle dynamics in large artery flows – Implications for modeling arterial embolisms. J Biomech 2017; 52:155-164. [DOI: 10.1016/j.jbiomech.2016.12.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 11/07/2016] [Accepted: 12/21/2016] [Indexed: 10/20/2022]
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10
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Grases F, Söhnel O, Zelenková M, Rodriguez A. Phytate effects on biological hydroxyapatite development. Urolithiasis 2015; 43:571-2. [DOI: 10.1007/s00240-015-0814-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 08/04/2015] [Indexed: 10/23/2022]
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Mangialardo S, Cottignoli V, Cavarretta E, Salvador L, Postorino P, Maras A. Pathological biominerals: Raman and infrared studies of bioapatite deposits in human heart valves. APPLIED SPECTROSCOPY 2012; 66:1121-7. [PMID: 23031694 DOI: 10.1366/12-06606] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We studied pathological bioapatite from patients undergoing valvular replacement due to severe aortic and mitral stenosis. Three different types of mineralized human cardiac valves were analyzed. We used infrared and Raman spectroscopy to infer the presence of the carbonate group and evaluate the carbonate substitution in bioapatite structure. The Raman spectra showed that the pathological bioapatite is a B-type "carbonate-apatite" (CO(3)(2-) for PO(4)(3-)) similar to the major mineralized products derived from normal biomineralization processes occurring in the human body. Fourier transform infrared spectra (FT-IR) confirmed the B-type carbonate substitution (CO(3)(2-) for PO(4)(3-)) and showed evidence for the partial replacement of [OH] by [CO(3)] (A-type substitution). The carbonate content of the samples inferred by the spectroscopic measurements is in good agreement with the range of values estimated for biological apatite. On the contrary, the crystal size of the pathological apatite estimated using the percentage area of the component at 1059 cm(-1) of the infrared spectrum is in the nanometer range and it is significantly smaller than the crystal size of normal mineralized tissues.
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12
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Söhnel O, Grases F. Supersaturation of body fluids, plasma and urine, with respect to biological hydroxyapatite. ACTA ACUST UNITED AC 2011; 39:429-36. [PMID: 21573694 DOI: 10.1007/s00240-011-0387-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 04/26/2011] [Indexed: 01/17/2023]
Abstract
Supersaturation of body fluids, specifically of plasma and urine, with respect to biological hydroxyapatite was evaluated taking into account calcium complexation, fraction of total phosphorus present as hydrogen phosphate ions, solubility of carbonated hydroxyapatite and the size dependency of equilibrium solubility. Plasma is always supersaturated with respect to apatitic solid phase and thus calcific deposits are formed unless a sufficient quantity of potent inhibitors is present. When urinary pH is lower than 6.3 for normal urine hydroxyapatite cannot appear in renal stones, at higher pH apatitic renal stones can be formed. Predictions based on supersaturation calculated for different conditions correspond well with clinical observations.
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Affiliation(s)
- Otakar Söhnel
- Faculty of Enviromental Studies, University of J. E. Purkyne, Usti n.L., Czech Republic
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