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Vassaki M, Hadjicharalambous C, Turhanen PA, Demadis KD. Structural Diversity in Antiosteolytic Bisphosphonates: Deciphering Structure-Activity Trends in Ultra Long Controlled Release Phenomena. ACS Appl Bio Mater 2023; 6:5563-5581. [PMID: 37982716 DOI: 10.1021/acsabm.3c00770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
Bisphosphonate (BP)-based treatments have been extensively prescribed for bone-related conditions, particularly for osteoporosis. Their low bioavailability creates the need for prescribed dosage increase to reach therapeutic levels but generates a plethora of undesirable side effects. A viable approach to alleviating these issues is to design and exploit controlled release strategies. Herein, the controlled release profiles of 15 structurally characterized BPs (actual drugs and structural analogs) were thoroughly studied from tablets containing three (cellulose, lactose, and silica) or two (cellulose, and silica) excipients in human stomach-simulated pH conditions. The BPs were of two types, alkyl-BPs and amino-BPs. Alkyl-BPs included four derivatives of etidronate (acid, disodium, tetra-sodium, and monopotassium forms), medronic acid, and three analogs of etidronate, in which the -CH3 group was replaced by the moieties -H, -CH2CH2CH3, and -CH2CH2CH2CH2CH3. Amino-BPs included the commercial drugs pamidronate, alendronate, neridronate, and ibandronate, as well as three analog compounds. Release curves were constructed based on data taken from 1H NMR peak integration and were expressed as "% BP release" vs time. The controlled release profiles (initial release rate, plateau value, etc.) were correlated with certain structural features (number of hydrogen and metal-oxygen bonds), showing that the molecular and crystal lattice features of each BP profoundly influence its release characteristics. It was concluded that for all BPs, in general, the initial rate became lower as the total number of lattice interactions increased. For the alkyl-BPs elongation of the alkyl side chain seems to decelerate the release. Amino-BPs, in general, show slower release than the alkyl-BPs. No adverse effects of alkyl- and amino-BP drugs on NIH3T3 cell viability were noted.
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Affiliation(s)
- Maria Vassaki
- Crystal Engineering, Growth and Design Laboratory, Department of Chemistry, University of Crete, Heraklion, Crete GR-71003, Greece
| | | | - Petri A Turhanen
- University of Eastern Finland, School of Pharmacy, Biocenter Kuopio, P.O. Box 1627, Kuopio FIN-70211, Finland
| | - Konstantinos D Demadis
- Crystal Engineering, Growth and Design Laboratory, Department of Chemistry, University of Crete, Heraklion, Crete GR-71003, Greece
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Hadjicharalambous C, Grispoldi L, Chalias T, Goga BC. A quantitative risk assessment of Listeria monocytogenes from prevalence and concentration data: Application to a traditional ready to eat (RTE) meat product. Int J Food Microbiol 2022; 379:109843. [DOI: 10.1016/j.ijfoodmicro.2022.109843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 06/23/2022] [Accepted: 07/17/2022] [Indexed: 11/29/2022]
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Hadjicharalambous C, Alpantaki K, Chatzinikolaidou M. Effects of NSAIDs on pre-osteoblast viability and osteogenic differentiation. Exp Ther Med 2021; 22:740. [PMID: 34046094 DOI: 10.3892/etm.2021.10172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 10/28/2020] [Indexed: 12/13/2022] Open
Abstract
Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of a variety of musculoskeletal conditions, injuries and after surgery for postoperative pain management. Their use has been associated with impaired bone healing, possibly due to a multifactorial function, which may include inhibition of osteoblast recruitment and differentiation. However, up to date, there is no consensus regarding the impact of NSAIDs on bone-healing. The aim of the current study was to investigate the effects of five NSAIDs on the cellular functions of mouse MC3T3-E1 pre-osteoblasts. Cells were treated with the non-selective COX inhibitors lornoxicam and diclofenac, the COX-2 selective inhibitors parecoxib, meloxicam and paracetamol, as well as steroidal prednisolone at different doses and exposure times. The PrestoBlue™ technique was used to measure cell viability, an enzymatic assay was employed for alkaline phosphatase (ALP) activity and alizarin red S mineral staining was used to determine osteogenic differentiation. All drugs had a negative impact on pre-osteoblast cell growth, with the exception of paracetamol. Lornoxicam, diclofenac and meloxicam reduced ALP activity, while the other NSAIDs had no effect and prednisolone strongly increased ALP activity. In contrast, calcium deposits were either unaffected or increased by NSAID treatments but were significantly decreased by prednisolone. These results provide evidence that NSAIDs may adversely affect the viability of mouse pre-osteoblast cells but their actions on the osteogenic differentiation are drug-specific. The direct comparison of the effects of different NSAIDs and prednisolone on pre-osteoblasts may serve to place some NSAIDs in a preferential position for analgesic and anti-inflammatory therapy during bone repair.
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Affiliation(s)
- Chrystalleni Hadjicharalambous
- Department of Materials Science and Technology, University of Crete, Heraklion 70013, Greece.,Department of Chemistry, University of Crete, Heraklion 70013, Greece
| | - Kalliopi Alpantaki
- Department of Orthopedics and Trauma, Venizeleion General Hospital of Heraklion, Heraklion 71409, Greece
| | - Maria Chatzinikolaidou
- Department of Materials Science and Technology, University of Crete, Heraklion 70013, Greece.,Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology Hellas (FORTH), Heraklion 70013, Greece
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Grispoldi L, Karama M, Armani A, Hadjicharalambous C, Cenci-Goga BT. Staphylococcus aureus enterotoxin in food of animal origin and staphylococcal food poisoning risk assessment from farm to table. Italian Journal of Animal Science 2021. [DOI: 10.1080/1828051x.2020.1871428] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
| | - Musafiri Karama
- Department of Paraclinical Sciences, University of Pretoria, Onderstepoort, South Africa
| | - Andrea Armani
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | | | - Beniamino T. Cenci-Goga
- Department of Veterinary Medicine, Perugia, Italy
- Department of Paraclinical Sciences, University of Pretoria, Onderstepoort, South Africa
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Grispoldi L, Karama M, Sechi P, Iulietto MF, Hadjicharalambous C, Cenci-Goga B. Evaluation of a nitrite-free commercial preparation in the production of swine and roe deer (Capreolus capreolus) salami. Italian Journal of Animal Science 2021. [DOI: 10.1080/1828051x.2021.1874843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Luca Grispoldi
- Dipartimento di Medicina Veterinaria, Laboratorio di Ispezione degli Alimenti di Origine Animale, University of Perugia, Perugia, Italy
| | - Musafiri Karama
- Faculty of Veterinary Science, Department of Paraclinical Sciences, University of Pretoria, Onderstepoort, South Africa
| | - Paola Sechi
- Dipartimento di Medicina Veterinaria, Laboratorio di Ispezione degli Alimenti di Origine Animale, University of Perugia, Perugia, Italy
| | - Maria Francesca Iulietto
- Dipartimento di Medicina Veterinaria, Laboratorio di Ispezione degli Alimenti di Origine Animale, University of Perugia, Perugia, Italy
| | | | - Beniamino Cenci-Goga
- Dipartimento di Medicina Veterinaria, Laboratorio di Ispezione degli Alimenti di Origine Animale, University of Perugia, Perugia, Italy
- Faculty of Veterinary Science, Department of Paraclinical Sciences, University of Pretoria, Onderstepoort, South Africa
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Vassaki M, Papathanasiou KE, Hadjicharalambous C, Chandrinou D, Turhanen P, Choquesillo-Lazarte D, Demadis KD. Self-sacrificial MOFs for ultra-long controlled release of bisphosphonate anti-osteoporotic drugs. Chem Commun (Camb) 2020; 56:5166-5169. [DOI: 10.1039/d0cc00439a] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Metal-bisphosphonates are self-sacrificial controlled delivery systems that achieve ultra-long release of anti-osteoporotic bisphosphonate drugs.
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Affiliation(s)
- Maria Vassaki
- Crystal Engineering
- Growth and Design Laboratory
- Department of Chemistry
- University of Crete
- Crete
| | | | | | - Daphne Chandrinou
- Crystal Engineering
- Growth and Design Laboratory
- Department of Chemistry
- University of Crete
- Crete
| | - Petri Turhanen
- University of Eastern Finland
- School of Pharmacy
- Biocenter Kuopio
- Kuopio
- Finland
| | | | - Konstantinos D. Demadis
- Crystal Engineering
- Growth and Design Laboratory
- Department of Chemistry
- University of Crete
- Crete
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Abstract
Ready to Eat (RTE) cooked meat products are among the most consumed RTE food subcategories in the EU. They are also associated with the highest number of listeriosis cases per year. Contamination with Listeria monocytogenes may arise from post-processing and its growth is often supported by the pH and water activity of the product. L. monocytogenes may grow during refrigeration and reach unacceptable levels at the time of consumption, posing a public health risk. The aim of this study was to conduct a Quantitative Microbiological Risk Assessment (QMRA) of L. monocytogenes in a traditional Italian RTE cooked meat product. Data for the risk assessment included prevalence and concentration of the microorganism, temperature-time conditions during transport and storage, information on the growth of the microorganism and its potential for disease (dose-response). These data were obtained from laboratory analysis of product samples (n = 50), a consumer survey (n = 160), recordings of temperatures of domestic refrigerators (n = 60) and were complemented with information from the literature. The data were described with appropriate probability distributions and introduced into a previously described growth model of L. monocytogenes. Based on the above components, a probabilistic model was created to evaluate the growth of L. monocytogenes at each stage of the product pathway (retail storage, transportation and domestic storage) using Monte Carlo simulations. The model design for this pathogen/food product combination, alongside with the findings of the study are included in a separate publication (manuscript under preparation). The results may help risk managers to apply appropriate control measures to minimise the public health risk. The project contributed to further education of the fellow, especially in the use of QMRA risk analysis tools and laid the foundations for future collaborations between the fellow's home institution, the University of Crete, Greece and the University of Perugia, Italy.
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Hadjicharalambous C, Flouraki C, Narain R, Chatzinikolaidou M, Vamvakaki M. Controlling pre-osteoblastic cell adhesion and spreading on glycopolymer brushes of variable film thickness. J Mater Sci Mater Med 2018; 29:98. [PMID: 29946888 DOI: 10.1007/s10856-018-6112-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 06/18/2018] [Indexed: 06/08/2023]
Abstract
Controlling the cell behavior on biocompatible polymer surfaces is critical for the development of suitable medical implant coatings as well as in anti-adhesive applications. Synthetic glycopolymer brushes, based on sugar methacrylate monomers have been reported as robust surfaces to resist protein adsorption and cell adhesion. In this study, poly(D-gluconamidoethyl methacrylate) (PGAMA) brushes of various chain lengths were synthesized directly from initiator functionalized glass substrates using surface-initiated atom transfer radical polymerization. The glycopolymer film thicknesses were determined by ellipsometry, whereas the wettability and the morphology of the surfaces were characterized by static water contact angle measurements and atomic force microscopy, respectively. Stable, grafted films with thicknesses in the dry state between 4 and 20 nm and of low roughness (~1 nm) were obtained by varying the polymerization time. Cell experiments with MC3T3-E1 pre-osteoblasts cultured on the PGAMA brushes were performed to examine the effect of film thickness on the cell morphology, cytoskeleton organization and growth. The results revealed good cell spreading and proliferation on PGAMA layers of low film thickness, whereas cell adhesion was prevented on polymer films with thickness higher than ~10 nm, indicating their potential use in medical implants and anti-adhesive surfaces, respectively.
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Affiliation(s)
- Chrystalleni Hadjicharalambous
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, 711 10, Crete, Greece
- Department of Materials Science and Technology, University of Crete, Heraklion, 710 03, Crete, Greece
| | - Chara Flouraki
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, 711 10, Crete, Greece
- Department of Materials Science and Technology, University of Crete, Heraklion, 710 03, Crete, Greece
| | - Ravin Narain
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, T6G 1H9, Alberta, Canada
| | - Maria Chatzinikolaidou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, 711 10, Crete, Greece
- Department of Materials Science and Technology, University of Crete, Heraklion, 710 03, Crete, Greece
| | - Maria Vamvakaki
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, 711 10, Crete, Greece.
- Department of Materials Science and Technology, University of Crete, Heraklion, 710 03, Crete, Greece.
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Hadjicharalambous C, Alexaki VI, Alpantaki K, Chatzinikolaidou M. Effects of NSAIDs on the osteogenic differentiation of human adipose tissue-derived stromal cells. ACTA ACUST UNITED AC 2016; 68:1403-1408. [PMID: 27523985 DOI: 10.1111/jphp.12595] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/29/2016] [Indexed: 12/22/2022]
Abstract
OBJECTIVES Non-steroidal anti-inflammatory drugs (NSAIDs), used in the treatment of musculoskeletal pathologies, have been associated with impaired bone healing, possibly through inhibition of osteogenic differentiation. The adipose tissue (AT) is regarded as an attractive source of stromal cells for autologous cell transplantation in the bone. The effects of NSAIDs on human AT-derived stromal cells (hADSCs) are unknown. METHODS We examined the effect of several NSAIDs including meloxicam, parecoxib, lornoxicam, diclofenac and paracetamol on the proliferation of hADSCs by means of the PrestoBlue® viability assay, and the osteogenic differentiation capacity of hADSCs by means of the alkaline phosphatase (ALP) activity, calcium deposition by alizarin red staining and osteogenic gene expression by semi-quantitative PCR. KEY FINDINGS Most of the drugs enhanced hADSC cell growth, while either positively affecting or not influencing alkaline phosphatase (ALP) activity, calcium deposition and osteogenic gene expression. Moreover, selective COX-2 inhibitor NSAIDs, such as meloxicam or parecoxib, were advantageous over the non-selective COX-1 and COX-2 inhibitor NSAIDs lornoxicam and diclofenac. CONCLUSIONS Altogether through this study, we show that NSAIDs, possibly depending on their selectivity for COX inhibition, leave the osteogenic differentiation capacity of hADSCs unaltered or might even enhance it.
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Affiliation(s)
- Chrystalleni Hadjicharalambous
- Department of Materials Science and Technology, University of Crete, Heraklio, Greece.,Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology Hellas (FORTH), Heraklion, Greece
| | - Vasileia Ismini Alexaki
- Department of Clinical Pathobiochemistry, Medical Faculty, Technische Universität Dresden, Dresden, Germany.
| | - Kalliopi Alpantaki
- Department of Orthopedics and Trauma, University Hospital of Heraklion, Crete, Greece
| | - Maria Chatzinikolaidou
- Department of Materials Science and Technology, University of Crete, Heraklio, Greece. .,Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology Hellas (FORTH), Heraklion, Greece.
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Hadjicharalambous C, Prymak O, Loza K, Buyakov A, Kulkov S, Chatzinikolaidou M. Effect of Porosity of Alumina and Zirconia Ceramics toward Pre-Osteoblast Response. Front Bioeng Biotechnol 2015; 3:175. [PMID: 26579516 PMCID: PMC4623495 DOI: 10.3389/fbioe.2015.00175] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 10/13/2015] [Indexed: 11/17/2022] Open
Abstract
It is acknowledged that cellular responses are highly affected by biomaterial porosity. The investigation of this effect is important for the development of implanted biomaterials that integrate with bone tissue. Zirconia and alumina ceramics exhibit outstanding mechanical properties and are among the most popular implant materials used in orthopedics, but few data exist regarding the effect of porosity on cellular responses to these materials. The present study investigates the effect of porosity on the attachment and proliferation of pre-osteoblastic cells on zirconia and alumina. For each composition, ceramics of three different porosities are fabricated by sintering, and characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray powder diffraction. Cell proliferation is quantified, and microscopy is employed to qualitatively support the proliferation results and evaluate cell morphology. Cell adhesion and metabolic activity are found comparable among low porosity zirconia and alumina. In contrast, higher porosity favors better cell spreading on zirconia and improves growth, but does not significantly affect cell response on alumina. Between the highest porosity materials, cell response on zirconia is found superior to alumina. Results show that an average pore size of ~150 μm and ~50% porosity can be considered beneficial to cellular growth on zirconia ceramics.
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Affiliation(s)
| | - Oleg Prymak
- Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Essen, Germany
| | - Kateryna Loza
- Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Essen, Germany
| | - Ales Buyakov
- Tomsk State University and ISPMS RAS, Tomsk, Russia
| | | | - Maria Chatzinikolaidou
- Department of Materials Science and Technology, University of Crete, Heraklion, Greece
- IESL-FORTH, Heraklion, Greece
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Hadjicharalambous C, Kozlova D, Sokolova V, Epple M, Chatzinikolaidou M. Calcium phosphate nanoparticles carrying BMP-7 plasmid DNA induce an osteogenic response in MC3T3-E1 pre-osteoblasts. J Biomed Mater Res A 2015; 103:3834-42. [DOI: 10.1002/jbm.a.35527] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 05/12/2015] [Accepted: 06/16/2015] [Indexed: 02/06/2023]
Affiliation(s)
| | - Diana Kozlova
- Institute of Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen; Universitaetsstr. 5-7 Essen 45117 Germany
| | - Viktoriya Sokolova
- Institute of Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen; Universitaetsstr. 5-7 Essen 45117 Germany
| | - Matthias Epple
- Institute of Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen; Universitaetsstr. 5-7 Essen 45117 Germany
| | - Maria Chatzinikolaidou
- Department of Materials Science and Technology; University of Crete; P.O. Box 2208 Heraklio 71001 Greece
- Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology Hellas (FORTH); N. Plastira 100 Heraklio 70013 Greece
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Hadjicharalambous C, Mygdali E, Prymak O, Buyakov A, Kulkov S, Chatzinikolaidou M. Proliferation and osteogenic response of MC3T3-E1 pre-osteoblastic cells on porous zirconia ceramics stabilized with magnesia or yttria. J Biomed Mater Res A 2015; 103:3612-24. [PMID: 25847599 DOI: 10.1002/jbm.a.35475] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 03/26/2015] [Accepted: 04/02/2015] [Indexed: 12/26/2022]
Abstract
Dense zirconia ceramics are used in bone applications due to their mechanical strength and biocompatibility, but lack osseointegration. A porous interface in contact with bone tissue may lead to better bone bonding but the biological properties of porous zirconia are not widely explored. The present study focuses on the manufacturing of an yttria- (YSZ) and a magnesia-stabilized (MgSZ) porous zirconia, and on their in vitro biological investigation. The sintered ceramics had similar characteristics of porosity, pore size and interconnectivity. Their elastic moduli and compressive strength values were within the range of the values of human cortical bone. MC3T3-E1 pre-osteoblasts were used to investigate the proliferation, alkaline phosphatase (ALP) activity, collagen deposition and expression profile of four genes involved in bone metabolism of cells on porous ceramics. Scanning electron and fluorescence microscopy were employed to visualize cell morphology and growth. Pre-osteoblasts adhered well on both ceramics but cell numbers on YSZ were higher. Cells exhibited an increase in ALP activity and collagen deposition after 14 days on both MgSZ and YSZ, with higher levels on YSZ. Real-time quantitative polymerase chain reaction (qPCR) showed that the expression of bone sialoprotein (Bsp) and collagen type I (col1aI) were significantly higher on YSZ. No significant differences were found in their ability to regulate the early gene expression of Runx2 and Alp. Nevertheless, the biomineralized calcium content was similar on both ceramics after 21 days, indicating that despite chemical differences, both scaffolds direct the pre-osteoblasts toward a mature state capable of mineralizing the extracellular matrix.
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Affiliation(s)
| | - Evdokia Mygdali
- Department of Materials Science and Technology, University of Crete, Heraklion, 71003, Greece
| | - Oleg Prymak
- Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, Essen, 45117, Germany
| | - Ales Buyakov
- Tomsk State University and ISPMS RAS, 2/4 Academicheskii Avenue, Tomsk, 634021, Russia
| | - Sergei Kulkov
- Tomsk State University and ISPMS RAS, 2/4 Academicheskii Avenue, Tomsk, 634021, Russia
| | - Maria Chatzinikolaidou
- Department of Materials Science and Technology, University of Crete, Heraklion, 71003, Greece.,IESL-FORTH, Vasilika Vouton, Heraklion, 71110, Greece
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Hadjicharalambous C, Buyakov A, Buyakova S, Kulkov S, Chatzinikolaidou M. Porous alumina, zirconia and alumina/zirconia for bone repair: fabrication, mechanical and
in vitro
biological response. Biomed Mater 2015; 10:025012. [DOI: 10.1088/1748-6041/10/2/025012] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Hadjicharalambous C, Sheynis T, Jelinek R, Shanahan MT, Ouellette AJ, Gizeli E. Mechanisms of alpha-defensin bactericidal action: comparative membrane disruption by Cryptdin-4 and its disulfide-null analogue. Biochemistry 2009; 47:12626-34. [PMID: 18973303 DOI: 10.1021/bi800335e] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mammalian alpha-defensins all have a conserved triple-stranded beta-sheet structure that is constrained by an invariant tridisulfide array, and the peptides exert bactericidal effects by permeabilizing the target cell envelope. Curiously, the disordered, disulfide-null variant of mouse alpha-defensin cryptdin-4 (Crp4), termed (6C/A)-Crp4, has bactericidal activity equal to or greater than that of the native peptide, providing a rationale for comparing the mechanisms by which the peptides interact with and disrupt phospholipid vesicles of defined composition. For both live Escherichia coli ML35 cells and model membranes, disordered (6C/A)-Crp4 induced leakage in a manner similar to that of Crp4 but had less overall membrane permeabilizing activity. Crp4 induction of the leakage of the fluorophore from electronegative liposomes was strongly dependent on vesicle lipid charge and composition, and the incorporation of cardiolipin into liposomes of low electronegative charge to mimic bacterial membrane composition conferred sensitivity to Crp4- and (6C/A)-Crp4-mediated vesicle lysis. Membrane perturbation studies using biomimetic lipid/polydiacetylene vesicles showed that Crp4 inserts more pronouncedly into membranes containing a high fraction of electronegative lipids or cardiolipin than (6C/A)-Crp4 does, correlating directly with measurements of induced leakage. Fluorescence resonance energy transfer experiments provided evidence that Crp4 translocates across highly charged or cardiolipin-containing membranes, in a process coupled with membrane permeabilization, but (6C/A)-Crp4 did not translocate across lipid bilayers and consistently displayed membrane surface association. Thus, despite the greater in vitro bactericidal activity of (6C/A)-Crp4, native, beta-sheet-containing Crp4 induces membrane permeabilization more effectively than disulfide-null Crp4 by translocating and forming transient membrane defects. (6C/A)-Crp4, on the other hand, appears to induce greater membrane disintegration.
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Affiliation(s)
- Chrystalleni Hadjicharalambous
- Institute of Molecular Biology and Biotechnology, FORTH, and Department of Biology, University of Crete, Heraklion, Crete, Greece
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Hadjicharalambous C, Dent G, May RD, Handy RLC, Anderson IK, Davies DE, Djukanovic R. Measurement of eotaxin (CCL11) in induced sputum supernatants: validation and detection in asthma. J Allergy Clin Immunol 2004; 113:657-62. [PMID: 15100669 DOI: 10.1016/j.jaci.2004.01.757] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Induced sputum is widely used in asthma research; however, for many mediators, the detection methods have not been validated. OBJECTIVE We sought to optimize the method of detection of eotaxin, an important chemokine acting through the CCR3 receptor on eosinophils, basophils, and T(H)2 cells. METHODS Induced sputum from normal and asthmatic subjects was processed with dithioerythritol (DTE) or PBS; recovery of eotaxin was assessed by means of ELISA before and after spiking with recombinant eotaxin. Furthermore, the effects of removing DTE by means of ultrafiltration or the addition of protease inhibitors and high-speed centrifugation on endogenous levels and spiking recovery of eotaxin were assessed. RESULTS Endogenous eotaxin was undetectable in DTE-processed samples, with a mean of only 30% (SD, 13%) spike recovery. DTE had no effect on the immunoassay capture antibody but dramatically reduced the detection of recombinant eotaxin. Removal of DTE from sputum before immunoassay did not improve detection, although it restored the recovery of a subsequent eotaxin spike. In contrast, PBS-processed sputum resulted in an eotaxin spike recovery of 101% (SD, 20%). Addition of protease inhibitors or high-speed centrifugation had no effect on eotaxin detection. By using this optimized protocol, eotaxin levels in PBS-processed sputum samples were found to be significantly increased in asthmatic sputum (P<.05). CONCLUSION Measurement of eotaxin by means of immunoassay is adversely affected by DTE, possibly through irreversible denaturation of epitopes, which makes eotaxin undetectable by using the immunoassay antibody. Sputum samples should be processed into PBS for assessment of eotaxin, which is present at increased levels in asthmatic sputum.
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Affiliation(s)
- Chrystalleni Hadjicharalambous
- Department of Respiratory Cell and Molecular Biology, Division of Infection, Inflammation and Repair, University of Southampton School of Medicine, General Hospital, Tremona Road, Southampton SO16 6YD, United Kingdom
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Dent G, Hadjicharalambous C, Yoshikawa T, Handy RLC, Powell J, Anderson IK, Louis R, Davies DE, Djukanovic R. Contribution of eotaxin-1 to eosinophil chemotactic activity of moderate and severe asthmatic sputum. Am J Respir Crit Care Med 2004; 169:1110-7. [PMID: 15001461 DOI: 10.1164/rccm.200306-855oc] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The CC chemokine eotaxin-1 (CCL11) is chemotactic for eosinophils, basophils, and type 2 helper T cells and may play a role in allergic inflammation. We investigated its contribution as an eosinophil chemoattractant in asthmatic airway secretions (sampled as induced sputum), which possess chemotactic activity for eosinophils and T cells. Sputum samples collected from healthy subjects and subjects with mild, stable-moderate, unstable-moderate, and severe asthma were processed with phosphate-buffered saline and assayed for eotaxin by ELISA and for eosinophil chemotactic activity by fluorescence-based chemotaxis assay. The contribution of eotaxin to chemotactic activity was studied by using a high-affinity neutralizing human anti-eotaxin antibody, CAT-213. Sputum eotaxin concentration was significantly raised in moderate and severe asthma (p < 0.05 versus healthy control subjects) but not in mild asthma. Chemotactic activity was significantly increased in all asthmatic groups relative to healthy subjects (p < 0.05) and was significantly inhibited by CAT-213 (100 nM) in subjects with moderate and severe asthma, with median inhibition of 52% (p < 0.05), 78% (p < 0.0001), and 86% (p < 0.0001), respectively, in samples representing stable-moderate, unstable-moderate, and severe asthma. Eotaxin contributed to the eosinophil chemotactic activity of sputum from subjects with more severe forms of asthma but not mild asthma, suggesting that its contribution is more important in more severe disease. This activity is inhibited significantly by CAT-213.
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Affiliation(s)
- Gordon Dent
- Respiratory Cell and Molecular Biology, Division of Infection, Inflammation, and Repair, University of Southampton School of Medicine, Southampton, United Kingdom.
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