The Role And Mechanism Of Periostin In Capsular Formation Of Human Breast Implants

ObjectiveWith the development of surgical technology and new materials,breast augmentation has become one of the most common aesthetic procedures.Polyacrylamide hydrogel(PAAG)injective breast augmentation was popular in China during the last decade of last century and the beginning of this century.Millions of women received breast augmentation using this material.Although PAAG injection has been prohibited in most countries nowadays,the consequences and long-term complications will be cruel for a long period.At present,silicon breast implants has occupied the world market.Capsular contraction is the most common complication after breast augmentation,and is the major reason underlying patient dissatisfaction and additional subsequent surgeries.The incidence of capsular contraction ranged from 2.8%to20.4%in previous reports.However,the etiology is not well understood Periostin is a kind of matricellular protein,a member of TGF-? superfamily.Published researches have demonstrated that periostin plays an important role in fibrosis,tissue remodeling,and collagen cross-linking.This study was to collect the cases that underwent injected PAAG removal surgery,investigate the clinical,radiological and pathological character,and analyze the relationship between complication and pathological change;to collect the specimen of breast implant capsule,and investigate the clinicopathological character;to analyze the relationship between the degree of capsular fibrosis and the expression of periostin and other fibrosis-related cytokines.;to product lentivirus vectors inducing periostin over-expression and interruption shRNA plasmid to infect human breast derived fibroblasts,observe the change of protein and mRNA of periostin and other fibrosis-related cytokines,and observe the role of periostin in the proliferation and differentiation of fibroblasts and collagen generation and cross-linking.We sought to research the role and mechanism of periostin in the process of capsule formation and contraction,in the hope of giving clues to the next study of antagonism and further decreasing the capsule contraction.Methods(1)Cases that underwent injected PAAG removal surgery were collected.The clinical,radiological and pathological character were investigated,and the relationship between complication and pathological change were analyzed.(2)The specimen of silicon implant capsule were collected.The clinicopathological character were investigated,and the relationship between complication and pathological change were analyzed.(3)Periostin,Fibronectin,Tenascin-C,LOX and ?-SMA immunohistochemistry were performed in the PAAG gel capsule and silicon implant capsule.Image analysis was used to observe the relationship between the expression of these protein and the degree of capsule fibrosis and contraction.(4)Periostin expression and interference shRNA plasmid were constructed in vitro.We identified the expression plasmid and screened the most effective silencing plasmid.(5)Periostin expression and interference shRNA lentivirus vectors were produced.Human breast derived fibroblasts HMF7630 were infected and screened to establish stable cell strains.(6)CCK8 assay was performed to observe the influence of periostin on the proliferation of fibroblasts.(7)Using western blot and QPCR to test the protein and mRNA of periostin,LOX,BMP-1,Fibronectin,Tenascin-C.(8)Immunofluorescence was used to observe the influence of periostin on the expression of ?-SMA.(9)Hydroxyproline was measured to estimate the influence of periostin on the collagen content.Results(1)Specimens from 90 cases that underwent breast injected PAAG removal surgery were collected.The complications included masses formation(75.58%),pain(45.35%),gel migration(22.09%),deformation(18.60%)and infection(16.28%)et al.Foreign body reaction,fibrosis,and inflammation are the main morphological characters microscopically.The mammary gland around the gel displayed atrophy(20.00%)and adenosis(36.67%).Two cases(2.23%)were accompanied by malignant tumors(2.23%).(2)21 Capsule specimens from 11 cases of breast implant were collected,including 12 of Baker ?-?,9 of Baker ?-? according to the clinical degree of capsule contraction.Capsule formation was observed in 20 specimens microscopically.Inflammation increased in the obvious contracted capsule.There was a tendency that the density of fibroblasts increased in obvious contracted capsule.(3)Immunohistochemistry showed that,in PAAG capsule,the expression of periostin,LOX and ?-SMA were positively correlated with the fibrosis,and the expression of periostin was positively correlated with Fibronectin,Tenascin-C,LOX and ?-SMA;in silicon implant capsule,the expression of periostin,Fibronectin,Tenascin-C,LOX and ?-SMA increased with the aggravation of capsule contraction.(4)The DNA sequence of periostin expression plasmid was correct through the validation by agarose gel electrophoresis and sequencing.The periostin expression and interference plasmid effectively expressed and interfered periostin protein and mRNA.The lentivirus vectors were produced successfully.The efficiency of infection was high.(5)CCK8 assay showed that,the mPeriostin-HMF7630 cell strain had a faster proliferation compared with the ctrl-mPeriostin-HMF7630 cell strain,while the shPeriostin cell strain had a lower proliferation compared with the ctrl-shPeriostin cell strain.(6)After 4 weeks' screening,the protein and mRNA of periostin,LOX,BMP-1,Fibronectin,and Tenascin-C increased in mPeriostin cell strain,and decreased in shPeriostin cell strain.(7)The Immunofluorescence showed that the expression of ?-SMA increased in mPeriostin cell strain,and decreased in shPeriostin cell strain.(8)Hydroxyproline testing showed a high collagen content in mPeriostin cell strain compared with the ctrl-mperiostin cell strain.Conclusions(1)The complications after PAAG injective breast augmentation were various and complex.The most common complication was mass.The basic pathological changes included foreign body reaction,fibrosis and inflammation.Although there was no direct evidence that PAAG would cause malignant tumors,there was possibility that the mass and induration caused by PAAG could interfere with the early screening of breast cancer.(2)Capsule formation was the common pathological change around breast implant.The severity of inflammation increased with the aggravation of capsular contraction.There was a tendency that the fibroblasts density increased in obvious contracted capsule.(3)The expression of periostin,Fibronectin,Tenascin-C,LOX and ?-SMA increased with the aggravation of capsule fibrosis and contraction.(4)Periostin stimulates the proliferation of fibroblasts,regulates the expression of fibrosis-ralated cytokines such as LOX,BMP-1,Fibronectin,and Tenascin-C,promotes the fibroblasts to express ?-SMA and differentiate into myofibroblasts,and contributes to the collagenous generation and cross-linking in human derived fibroblasts in vitro.Our research demonstrated that periostin was a key mediator in the process of capsular formation and contraction.