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BIOGLASS, A NEW TREND TOWARDS CLINICAL BONE TISSUE ENGINEERING.

Byline: HASHMAT GUL, SHAHREEN ZAHID, MUHAMMAD KALEEM and SHAHAB-UD-DIN

ABSTRACT

(It is submitted that the list of the published articles available on the Pubmed database were extracted using the key words "Osteogenesis and Bioglass" on 3rd April, 2015 followed by extraction of the full text articles from different sources and then thorough review of all the articles was done in 4 months' time period (from April to July 2015) to reproduce this manuscript. Authros).

Bioglass also called a bioactive glass has an inherent osteogenic potential, thus, provide new strategies to regenerate diseased or lost bone with minimum exposure to multiple materials.

This article covers the systematic review of all the research done on bioglass and osteogenesis since 2007 till present on PubMed based on the eligibility criteria.

The main objectives of the study were to evaluate the latest trend of bioglass research, to determine its osteogenic potential and to comprehend its possible clinical applications.

Increasing trend is observed towards the in vivo research of bioglass for its osteogenic potential and effective clinical applications. In the field of dentistry, the use of bioglass is identified in quick healing and regeneration of intrabony defects especially the periodointium with a potential application in periodontology and maxillofacial surgery. Bioglass is a more potent and cheap alternative to bone implantation and transplantation with minimum side effects and efficient replacement with body's own new regenerated tissue.

INTRODUCTION

Bioactive glasses are surface reactive glass-ceramic biomaterials which are investigated extensively for its use as a biocompatable implant materials in the human body to repair and replace diseased / damaged bone tissue. Larry Hench and Colleagues at the University of Florida first developed these materials in the late 1960s. Bioglass constitute synthetic bone graft materials. These are available to surgeons in a particulate form, putty form and porous scaffolds. These are being investigated in many forms, in particular as porous 3-D scaffolds.

Bioglass alone or in composite form assessed for its osteogenic potential in different scenarios. Most of the research regarding the osteogenic potential of bioglass is carried out in the past 10-15 years according to published studies on pubmed as evident from the graph, Fig 1. In the graph, the arrow on the bar (2013-2015) shows an increasing trend towards the research of bioglass for its osteogenic potential as it only covers the publications on pubmed from 2013 till 2014.

METHODOLOGY

At Army Medical College, NUST, the literature was thoroughly reviewed systematically using the search term 'osteogenesis AND bioglass' in PubMed with a limitation to PubMed-registered papers published. Using the key words "osteogenesis AND bioglass" a list of all the published studies available on PubMed was extracted on 02/04/2015 and it revealed a total of 66 studies. Screening of 59 studies since April 1997 was done, out of which 39 studies were short-listed for review and analysis due to the raising trend of research in this field during the last 10 years (2006-2015). In this paper 21 papers were included and 18 papers were excluded on the basis of following criteria:

Inclusion Criteria

a) Studies which promoted biocompatibility and bioactivity.

) Studies in which enhanced osteoblastic activity was observed with bone formation.

c) Studies in which osteogenesis was induced with minimum inflammation.

d) Studies in which bony defects were healed with new bone formation.

Exclusion Criteria

a) Studies where osteogenesis didn't occur were excluded.

) Studies where the focus was on properties other than osteogenic potential of bioglass.

c) Studies where osteogenesis halted or decreased due to some factor.

d) Articles which could not be accessed were excluded.

RESULTS

Conclusive Remarks

i) The trend of research on bioglass for its osteogenic potential has increased many folds especially in the last 10 years.

ii) Bioglass has an inherent osteogenic potential.

iii) The osteogenic potential of BG can be improved by using 3D, porous and interconnected scaffolds.

iv) Mesenchymal stem cells augmentation of BG scaffolds does not enhance its osteogenic potential.

v) Further animal usage tests and clinical trials needed to bring it into dental clinics.

DISCUSSION

In 1981 the first in vivo study regarding the osteogenic potential of bioglass was published on pubmed.22

The trend towards exploring bioglass for its osteogenic potential started to develop in late 90's. In the past 10 years the trend of in-vivo studies regarding the osteogenic potential of bioglass had increased many fold as evidenced from the graph in Fig 1. Out of the 39 published in-vivo studies, 14 studies were based on in vitro, culture tests, 18 studies focus on in vivo, animal implantation tests and only three in vivo, clinical trials. Different materials were composited with bioglass in an attempt to enhance its osteogenic potential. In some cases bioglass scaffolds were augmented with stem cells to facilitate bone growth. Satisfactory results showing significant bone formation in suitable time were observed in most animal implantation tests and a few clinical trials, directing the potential of more clinical trials to establish its clinical use.

Bioglass is an excellent bioactive material for bone regeneration. Initially bioglass particles were coated on the surface of various bone implants and in vivo animal implantation studies were carried out to evaluate any improvement in osteointegration in bioglass coated implants. The silica coated Bioverit II specimens showed improved osteogenic rate and intensity along minimal inflammation.21 Pure hydroxyapatite (HAp) and a biphasic calcium phosphate were used to make porus struts with bioglass. Beta-TCP/bioglass-based implants proved superior to HAp/bioglass implants.15

Different substances have been composited with bioglass in different studies overtime to enhance its osteogenic potential including borate7, calcium sulphate23, hydroxyapatite15 and polymers.16 Bioglass is available in the form of 3D porous scaffolds, putty-form and injectable form with polymeric carriers and require surgical placement into bony defect site where it gradually resorb with new bone ingrowth.12,13,19 By increasing the porosity of 3D bioglass scaffolds, the inherent osteogenic potential of bioglass is multiplied and the resultant bone formation is enhanced.

In healing of bony defects, bioglass composites have been shown to exhibit improved biocompatibility and osteogenesis. In vitro culture study of novel borate BG exhibited excellent cytocompatability with mouse osteoblasts7 but the osteogenic potential of boron modified bioglass in vivo implantation study remained same as normal 45S5 bioglass.14 Further in vivo animal implantation tests, simulating clinical scenarios were carried out to assess the qualitative tissue response to various BG composites. Mesoporous BG/silk scaffolds induced osteogenesis in local osteoporotic defects.2 Similarly, Polylactic acid/BG scaffolds exhibited good biocompatibility and induced osteogenesis with minimum inflammation1, where as Calcium sulphate coatings on bioglass promoted better osteoconduction in bone repair process.12

TABLE 1: DATA OF STUDIES FOCUSING ON THE OSTEOGENIC POTENTIAL OF BIOGLASS.

Citations###Type of study###Therapeutic###Time taken###Reason for###Conclusive

###agent###inclusion###Remarks

Eldesoqi, 2014###Comparative###Composite ma-###3 months###Biocompatable.###Further in vivo/

#351###study: rat###terial, polylactic###Induce qualita-###usage tests

###model, calvarial###acid (PLA) and###tive osteogene-###required.

###defec###20% or 40% bio-###sis with mini-

###glass (BG20 and###mum inflamma-

###BG40). Control:###tion.

###PLA scaffold

Cheng, 2013###In vivo study###3D scaffolds,###2-4 weeks.###MBG/silk###Further in vivo/

#362###Rat models: bio-###BG/silk and meso-###scaffolds act as###usage tests

###material-based###porous BG/silk.###potential substi-###required.

###approach.###Control: pure###tute for treating

###silk scaffolds.###local osteoporot-

###ic defects.

Mladenovi,###In vitro culture###BG, BG disso-###Si exhibit stim-###Further usage

2014 #373###study on mouse###lution extracts###ulatory effects###tests required.

###osteoclasts via###and Si contain-###on osteoblasts

###calvarial bone###ing cell culture###and inhibitory

###resorption assay###medium.###effects on osteo-

###and osteoclast for-###clasts.

###mation assays.

Li, Lei et al.###Usage tests on###(W/W%) PMMA###3 months / 6###PBC II and PBC###Further usage

20134###white rabbit###to BG to chi-###months post-###III show >###tests required.

###models with###tosan, PBC I###surgery###osteogenesis .

###porous bioactive###(50: 40:10), PBC###Better biocom-

###bone cement###II (40:50:10),###patibility than

###(PBC).###and PBC III###PMMA

###(30:60:10).

El-Gendy, Yang###In vitro culture###Culturing###Culture: 2/4###HDPSCs with###Usage tests

et al. 20125###and in vivo###human den-###weeks. Implan-###3D 45S5 Bio-###needed.

###implantation###tal pulp stem###tation: 8 weeks. glass scaffolds,

###study in mice.###cells(HDPSCs)###promote bone-

###Histological###in monolayers###like tissue

###and immuno-###and on 3D Bio-###formation.

###histochemical###glass(r) scaffolds

###analyses.###followed by

###intraperitoneal

###implantion in

###mice.

Shigeishi, Take- Clinical trial.###One-stage###33 months###IP-CHA, poten-###Further Clinical

chi et al. 20126 59 year old###implant inte-###tial scaffold for###trials needed.

###female. Pano-###gration with###osteoprogenitor

###ramic radio-###right maxillary###cells.

###graphic evalu-###sinus floor aug-

###ation###mentation with

###mixture grafts

###from the cor-

###tical bone and

###IP-CHA.

Wei, Zhang et###In vitro study###The novel###extract time of###Excellent cyto-###potential for

al. 20117###using cultures.###borate bioglass.###0-24 hours and###compatibility,###clinical applica-

###Osteoblasts###24-48 hours.###which plays###tion

###from mouse###regulatory ef-

###were cocultured###fects on the cell

###with extracts,###proliferation,

###alpha-MEM me-###secretion, and

###dium served as###migration.

###control group.

Kumar, Kumar###A pilot study.###10 patients###3-6 months###The new com-###Promise bet-

et al. 20118###Split mouth###were treated###posite alloplast###ter clinical

###study design.###either with open###resulted in bet-###outcomes in

###Osteogenesis###flap debride-###ter treatment###treatment of

###assessed via CT###ment alone or###outcomes.###aggressive peri-

###scan.###with new com-###odontititis.

###posite alloplas-

###t(HA, BG, Calci-

###um phosphate)

###implantation.

Xu, Su et al.###In vitro, cul-###A novel bio-###21 days cell###The BG-###BG-COL-PS

20119###tures of rat###mimetic com-###culture. 6 weeks###COL-PS/MSC###scaffolds have

###mesenchymal###posite scaffold###implantation.###constructs###the potential to

###stem cells(rM-###Bioglass-Col-###enhanced the###be applied in

###SCs) and in vivo###lagen-Phos-###efficiency of new###orthopedic and

###implantation###phatidylserine###bone forma-###reconstructive

###studies. Rat###(BG-COL-PS)###tion than pure###surgery.

###models. SEM###freeze-dry-###BG-COL-PS

###analysis.###ing technique.###scaffolds or

###rMSCs seeded###BG-COL/MSC

###on scaffolds and###constructs.

###cultured.

Xie, Yu et al.###in vivo implan-###Gradient coat-###4, 12, 24 weeks.###BG-nHA gra-###Further usage

201010###tation studies.###ings composed###dient coatings###tests required.

###Rabbit models###of bioactive###enhance the

###histologic and###glass and nano-###osteointegration

###histomorpho-###hydroxyapatite###of orthopaedic

###metric studies.###(BG-nHA) on###implant.

###titanium-alloy

###orthopaedic

###implants and

###surrounding

###bone tissue in

###vivo.

Zhang, Wang et###Comparative###Bone repair pro-###After 90 days###The bioactive###Calcium sul-

al. 200911###usage study.###cess in calvarial###osteoconduc-###glass covered###phate coatings

###Histological###defects using###tance observed.###with calcium###on BG promote

###evaluation. Rat###bioactive glass###sulfate barrier###osteoconduc-

###models.###(BG); calcium###association pre-###tion.

###sulfate barrier###sented a better

###(CSB); BG/CSB;###osteoconductive

###and autogenous###capacity when

###blood clot (con-###compared to iso-

###trol).###lated materials.

Nandi, Kundu###Bone implanta-###Porous BG###90 days###Bone formation###Porous bioglass

et al. 200913###tion test. Goat###scaffold###over the en-###scaffolds are po-

###models.###tire extension###tential orthope-

###of the defect###dic implants.

###independent of

###size of block in

###comparison to

###control group.

Gorustovich,###Usage test Bone###Particles of###15-30 days###Boron-modi-###Further clinical

Lopez et al.###implantation###boron-modi-###fied 45S5 BG###trials required

200614###test. Rats.###fied 45S5 BG###(45S5.2B) en-

###(45S5.2B)###hance osteogen-

###implanted into###esis initially.

###the intramedul-

###lary canal of rat

###tibiae. Control:

###45S5 BG.

Ghosh, Nandi et###Usage test Bone###Pure hydroxy-###Beta-TCP/bio-###Clinical trials

al. 200815###implantation###apatite (HAp)###glass-based im-###needed.

###test. Bengal###and a biphasic###plants superior

###goats.###calcium phos-###to HAp/bioglass

###phate used to###implants.

###make porus

###struts with

###bioglass.

Mylonas, Vidal###In vivo, im-###The combina-###4-7 weeks.###MSCs enhanced###Clinical trials

et al. 200716###plantation test.###tion of a poly-###bone formation###needed

###Dogs.###meric carrier###at early stag-

###with a granular###es of alveolar

###scaffold (bio-###repair. Final

###glass or HA/###result similar.

###TCP) allowed

###for the delivery

###of allogeneic

###mesenchymal

###stem cells(M-

###SCs).

Reilly, Radin et###Comparative###Alkaline phos-###BG induced###Further in vivo

al. 200717###study using Rat###phatase osteo-###bone growth in###studies needed.

###and human MSCs###genic markers###human patients

###cultured on BG.###assessed###is independent

###of MSCs differ-

###entiation

Tsigkou, Hench###Comparative###Poly-D,L-lac-###BG incorpora-###Bioglass has

et al. 200718###study using###tide (PDLLA)###tion enhanced###osteoinductive

###fetal osteoblasts###matrix and 45S5###osteoblast###potential

###cultured on bio-###BG particles at###proliferation,

###active resorb-###3 different con-###differentiation

###able composite###centrations (0%###and mineraliza-

###films###(PDLLA), 5%###tion.

###(P/BG5), and 40%

###(P/BG40).

Tsigkou, Hench

et al. 200718

Jones, Tsigkou###In vivo culture###Human osteo-###3 weeks###Mineralized###Ideal bone scaf-

et al. 200719###study###blasts cultured###bone formed###folds

###on porous 3D###without any

###scaffolds formed###growth factors.

###from 70S30C

###composition.

Wang, Lu et al.###Comparative###Sheep Implan-###6-12 weeks.###NovaBone###Further clinical

201120###study.###tation in spinal###Putty, had >###trials needed to

###bony defects.###bone content###establish effica-

###than the No-###cy of Novabone

###vaBone, both###putty.

###of which were

###significantly >

###than the empty

###control.

Vogt, Brandes###Usage tests.###Mice. Bioverit###2, 6, and 12###The osseogenic###Further clinical

et al. 200821###II implants###weeks###rate and intensity trials needed.

###A histological

###coated with a###increased in

###study. Plain

###nanoporous###coated Bioverit

###bioverit II

###silica layer in###II specimens.

###control.

###a mouse ear###Excellent bio-

###model.###compatibility

###(no inflamma-

###tion).

Silica, the main constituent of bioglass has duel effect in osteogenesis, i.e. it stimulates osteoblasts and inhibits osteoclasts, thus, promoting bone formation.3

Wang et al. 201120, performed a comparative study of two commercially available bioglass products. Following 6-12 weeks of implantation in spinal bony defects of sheep, NovaBone Putty, showed greater bone content than the NovaBone, both of which were significantly greater than the empty control. Further clinical trials needed to establish efficacy of Novabone putty.

Porous bioactive bone cements (PBC) with greater BG content showed greater osteogenesis and better biocompatibility than PMMA alone, so may reduce the fracture risk of adjacent vertebrae after vertebroplasty.4 Porous bioactive glass scaffolds are potential orthopedic implants as they exhibited bone formation over the entire bone defect in 90 days.13 Thus, directing the need of further in vivo investigation regarding osteogenic potential of various porous BG composite scaffolds and there possible applications in orthopedics.

In dentistry, our prime interest is the replacement of periodontium especially the alveolar ridge with new bone formation, to restore function and esthetics. Some animal usage tests using bioglass scaffolds and its composites targeted to establish the potential use of bioglass to replace the lost alveolar bone in cases of chronic periodontitis.15 Kumar, Kumar et al. 20118, performed a pilot study using split mouth design, 10 patients were treated either with open flap debridement alone or with new composite alloplast (Hydroxyapetite, Bioglass, Calcium phosphate) implantation. Better treatment outcomes were observed with new composite allopast in aggressive periodontititis. In this regard a few bioglass products are launched in the market namely Novabone and Novabone putty.20

In tissue engineering, mesenchymal stem cells in different carriers have been used extensively in vivo studies to find the most suitable and effective way to replace the lost tissues with new tissues. And in many studies quiet encouraging results were obtained.5

Similarly, considering the osteogenic potential of bioglass, many studies are performed in which porous bioglass scaffolds were augmented with mesenchymal stem cells to assess the rate of bone formation and the quality of resultant bone formed.19

Bioglass scaffolds with or without stem cell augmentation and growth factors gave same results in most studies indicating that bioglass is a selfsufficient osteogenic material and doesn't need stem cells for improved osteogenesis.16

CONCLUSION

In vivo studies using cultures in laboratory and implantation tests in different animals lead to the establishment of bioglass as an efficient osteogenic material with inherent osteoinductive and osteoconductive potential, thus proving it to be a highly bioactive material. Bone formation occurs with minimum inflammation and immunological response, catagorizing it as a highly biocompatible material. So, 3D, highly porous scaffolds can be safely used to treat intra-bony defects, osteoporotic orthopedic defects, aggressive periodontitis etc via bone regeneration.

In dentistry, limited use of bioglass as bone regenerative material is encountered in periodontology and maxillofacial surgery to repair the bony defects. Further clinical trials are needed for its potential use as a bone regenerative material under different clinical scenarios.

REFERENCES

1 Eldesoqi K, Henrich D, El-Kady AM, Arbid MS, El-Hady BMA, Marzi I, et al. Safety Evaluation of a Bioglass - Polylactic Acid Composite Scaffold Seeded with Progenitor Cells in a Rat Skull Critical-Size Bone Defect. PloS one. 2014; 9(2): 87642.

2 Cheng N, Wang Y, Zhang Y, Shi B. The osteogenic potential of mesoporous bioglasses/silk and non-mesoporous bioglasses/silk scaffolds in ovariectomized rats: in vitro and in vivo evaluation. PloS one. 2013; 8(11): 810-14.

3 Mladenovic Z, Johansson A, Willman B, Shahabi K, Bjorn E, Ransjo M. Soluble silica inhibits osteoclast formation and bone resorption in vitro. Acta biomaterialia. 2014; 10(1): 406-18.

4 Li Y, Lei W, Wang Z, Zhang Y, Niu E, Yu L, et al. [In vivo experiment of porous bioactive bone cement modified by bioglass and chitosan]. Zhongguo xiu fu chong jian wai ke za zhi= Zhongguo xiufu chongjian waike zazhi= Chinese journal of reparative and reconstructive surgery. 2013; 27(3): 320-25.

5 El-Gendy R, Yang XB, Newby PJ, Boccaccini AR, Kirkham J. Osteogenic differentiation of human dental pulp stromal cells on 45S5 Bioglass(r) based scaffolds in vitro and in vivo. Tissue Engineering Part A. 2012; 19(5-6): 707-15.

6 Shigeishi H, Takechi M, Nishimura M, Takamoto M, Minami M, Ohta K, et al. Clinical evaluation of novel interconnected porous hydroxyapatite ceramics (IP-CHA) in a maxillary sinus floor augmentation procedure. Dental materials journal. 2012; 31(1): 54-60.

7 Wei X, Zhang C, Huang W, Gu Y. [Effects of a novel borate bioglass on osteoblast behavior in vitro]. Zhongguo xiu fu chong jian wai ke za zhi= Zhongguo xiufu chongjian waike zazhi= Chinese journal of reparative and reconstructive surgery. 2011; 25(5): 606-9.

8 Kumar PG, Kumar JA, Anumala N, Reddy KP, Avula H, Hussain SN. Volumetric analysis of intrabony defects in aggressive periodontitis patients following use of a novel composite alloplast: a pilot study. Quintessence international (Berlin, Germany: 1985). 2011; 42(5): 375-84.

9 Xu C, Su P, Chen X, Meng Y, Yu W, Xiang AP, et al. Biocompatibility and osteogenesis of biomimetic Bioglass-Collagen-Phosphatidylserine composite scaffolds for bone tissue engineering. Biomaterials. 2011; 32(4): 1051-58.

10 Xie X-H, Yu X-W, Zeng S-X, Du R-L, Hu Y-H, Yuan Z, et al. Enhanced osteointegration of orthopaedic implant gradient coating composed of bioactive glass and nanohydroxyapatite. Journal of Materials Science: Materials in Medicine. 2010; 21(7): 2165-73.

11 Zhang J, Wang M, Cha JM, Mantalaris A. The incorporation of 70s bioactive glass to the osteogenic differentiation of murine embryonic stem cells in 3D bioreactors. Journal of tissue engineering and regenerative medicine. 2009; 3(1): 63-71.

12 Annalisa P, Furio P, Ilaria Z, Anna A, Luca S, Marcella M, et al. Anorganic bovine bone and a silicate-based synthetic bone activate different microRNAs. Journal of oral science. 2008; 50(3): 301-7.

13 Nandi SK, Kundu B, Datta S, De DK, Basu D. The repair of segmental bone defects with porous bioglass: an experimental study in goat. Research in veterinary science. 2009; 86(1): 162-73.

14 Gorustovich AA, Lopez JMP, Guglielmotti MB, Cabrini RL. Biological performance of boron-modified bioactive glass particles implanted in rat tibia bone marrow. Biomedical Materials. 2006; 1(3): 100.

15 Ghosh SK, Nandi SK, Kundu B, Datta S, De DK, Roy SK, et al. In vivo response of porous hydroxyapatite and btricalcium phosphate prepared by aqueous solution combustion method and comparison with bioglass scaffolds. Journal of Biomedical Materials Research Part B: Applied Biomaterials. 2008; 86(1): 217-27.

16 Mylonas D, Vidal MD, De Kok IJ, Moriarity JD, Cooper LF. Investigation of a thermoplastic polymeric carrier for bone tissue engineering using allogeneic mesenchymal stem cells in granular scaffolds. Journal of Prosthodontics. 2007; 16(6): 421-30.

17 Reilly GC, Radin S, Chen AT, Ducheyne P. Differential alkaline phosphatase responses of rat and human bone marrow derived mesenchymal stem cells to 45S5 bioactive glass. Biomaterials. 2007; 28(28): 4091-97.

18 Tsigkou O, Hench L, Boccaccini A, Polak J, Stevens M. Enhanced differentiation and mineralization of human fetal osteoblasts on PDLLA containing Bioglass(r) composite films in the absence of osteogenic supplements. Journal of Biomedical Materials Research Part A. 2007; 80(4): 837-51.

19 Jones JR, Tsigkou O, Coates EE, Stevens MM, Polak JM, Hench LL. Extracellular matrix formation and mineralization on a phosphate-free porous bioactive glass scaffold using primary human osteoblast (HOB) cells. Biomaterials. 2007; 28(9): 1653-63.

20 Wang Z, Lu B, Chen L, Chang J. Evaluation of an osteostimulative putty in the sheep spine. Journal of Materials Science: Materials in Medicine. 2011; 22(1): 185-91.

21 Vogt JC, Brandes G, Ehlert N, Behrens P, Nolte I, Mueller PP, et al. Free Bioverit(r) II implants coated with a nanoporous silica layer in a mouse ear model-a histological study. Journal of biomaterials applications. 2008.

22 Thieme V, Hofmann H, Heiner H, Berger G, Muller T, Zieger M. [The reaction between bioglass or biovitreous ceramics and rabbit tibia bone (author's transl)]. Zahn-, Mund-, und Kieferheilkunde mit Zentralblatt. 1980; 69(8): 707-18.

23 Haimi S, Moimas L, Pirhonen E, Lindroos B, Huhtala H, Raty S, et al. Calcium phosphate surface treatment of bioactive glass causes a delay in early osteogenic differentiation of adipose stem cells. Journal of Biomedical Materials Research Part A. 2009; 91(2): 540-47.
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