Degradation of differently processed Mg-based implants leads to distinct foreign body reactions(FBRs)through dissimilar signaling pathways

Mg alloys have mechanical properties compatible with human bones.However,their rapid degradation and associated foreign body reactions in vivo significantly limit their application for human implants.In this study,three differently processed Mg alloys,pure Mg(PM),cold extruded Mg alloy AZ31(CE AZ31),and fully annealed AZ31 Mg alloy(FA AZ31)were comparatively investigated for their potential as implants using a rat model.All three implanted Mg alloys do not show any impact on hepato-and renal function,nor any signs of observable changes to vital organs.Proteomics analysis of tissues directly contacting the implants 2.5 months post implantation revealed that FA AZ31 activates very few inflammation and immune associated signaling pathways;while the CE AZ31 and PM produce more significant inflammatory responses as confirmed by cytokine array analyses.Further,FA AZ31 activated pathways for cell organization and development that may improve the recovery of injured tissues.Structurally,EBSD analysis reveals that the FA AZ31 alloy has a higher ratio of first-order pyramidal orientated(10–11){10–1–2}grain texture with a value of 0.25,while PM and CE AZ31 alloys have lower ratios of first-order pyramidal orientated texture with the values of 0.16 and 0.17,respectively.This is associated with recovery and recrystallisation during annealing which promotes grain texture which exhibits enhanced degradation behaviours and induces a more limited immune response in vivo.In conclusion,the FA AZ31 demonstrated better biocompatibility and corrosion resistance and is a promising candidate for metal-based degradable implants which warrants further investigation.

Nanosilver alleviates foreign body reaction and facilitates wound repair by regulating macrophage polarization

Foreign body reactions induced by macrophages often cause delay or failure of wound healing in the application of tissue engineering scaffolds.This study explores the application of nanosilver(NAg)to reduce foreign body reactions during scaffold transplantation.An NAg hybrid collagen-chitosan scaffold(NAg-CCS)was prepared using the freeze-drying method.The NAg-CCS was implanted on the back of rats to evaluate the effects on foreign body reactions.Skin tissue samples were collected for histological and immunological evaluation at variable intervals.Miniature pigs were used to assess the effects of NAg on skin wound healing.The wounds were photographed,and tissue samples were collected for molecular biological analysis at different time points post-transplantation.NAg-CCS has a porous structure and the results showed that it could release NAg constantly for two weeks.The NAg-CCS group rarely developed a foreign body reaction,while the blank-CCS group showed granulomas or necrosis in the subcutaneous grafting experiment.Both matrix metalloproteinase-1(MMP-1)and tissue inhibitor of metalloproteinase-1(TIMP-1)were reduced significantly in the NAg-CCS group.The NAg-CCS group had higher interleukin(IL)-10 and lower IL-6 than the blank CCS group.In the wound healing study,M1 macrophage activation and inflammatory-related proteins inducible nitric oxide synthase(iNOS),IL-6,and interferon-(IFN-)were inhibited by NAg.In contrast,M2 macrophage activation and proinflammatory proteins(arginase-1),major histocompatibility complex-II(MHC-II),and found in inflammatory zone-1(FIZZ-1)were promoted,and this was responsible for suppressing the foreign body responses and accelerating wound healing.In conclusion,dermal scaffolds containing NAg suppressed the foreign body reaction by regulating macrophages and the expression of inflammatory cytokines,thereby promoting wound healing.

Foreign Body Reaction After Cochlear Implantation： A Case Report

Foreign body reaction is a rare complication after cochlear implantation.When such complications do occur,they may be intractable and difficult to be cured with antibiotics or surgical revision that may lead to cochlear reimplantation finally.In this article,we presented a patient with foreign body reaction who recovered well after cochlear reimplantation and has been in good health throughout the 6 years of follow-up at regular intervals in Affiliated Eye Ear Nose and Throat Hospital of Fudan University.

Diamond-Like Carbon Depositing on the Surface of Polylactide Membrane for Prevention of Adhesion Formation During Tendon Repair

Post-traumatic peritendinous adhesion presents a significant challenge in clinical medicine.This study proposes the use of diamond-like carbon(DLC)deposited on polylactic acid(PLA)membranes as a biophysical mechanism for anti-adhesion barrier to encase ruptured tendons in tendon-injured rats.The results indicate that PLA/DLC composite membrane exhibits more efficient anti-adhesion effect than PLA membrane,with histological score decreasing from 3.12±0.27 to 2.20±0.22 and anti-adhesion effectiveness increasing from 21.61%to 44.72%.Mechanistically,the abundant C=O bond functional groups on the surface of DLC can reduce reactive oxygen species level effectively;thus,the phosphorylation of NF-κB and M1 polarization of macrophages are inhibited.Consequently,excessive inflammatory response augmented by M1 macrophage-originated cytokines including interleukin-6(IL-6),interleukin-1β(IL-1β),and tumor necrosis factor-α(TNF-α)is largely reduced.For biocompatibility evaluation,PLA/DLC membrane is slowly absorbed within tissue and displays prolonged barrier effects compared to traditional PLA membranes.Further studies show the DLC depositing decelerates the release of degradation product lactic acid and its induction of macrophage M2 polarization by interfering esterase and PLA ester bonds,which further delays the fibrosis process.It was found that the PLA/DLC membrane possess an efficient biophysical mechanism for treatment of peritendinous adhesion.

Sutureless Intestinal Anastomosis with a Novel Device of Magnetic Compression Anastomosis

Objective To explore the feasibility and efficiency of a novel magnetic compression anastomats(MCAs) in intestinal anastomosis.Methods A total of 36 male mongrel canines underwent intestinal anastomosis using traditional hand-sewn(n=18) or a novel MCAs(n=18).We compared the anastomosis time,postoperative complications,bursting strength of anastomoses,gross appearance,and pathology between two groups at each time-point of follow-up.Results The mean anastomosis time with MCAs was significantly less than that with hand-sewn(8.50±1.95 vs.31.1±4.32 minutes,P<0.001).The blood stools and intussusceptions occurred in both groups during follow-up period.Only 1 mongrel canine receiving intestinal anastomosis by MCAs experienced anastomotic leakage.The average bursting pressure of anastomoses obtained from mongrel canines undergoing intestinal anastomosis by MCAs was significantly higher than that by traditional hand-sewn at 1 week's follow-up time(P<0.05).Gross appearance of the anastomoses constructed by MCAs was relatively smoother and flatter.Pathological evalution of anastomoses revealed that general inflammation was greater in hand-sewn anastomoses than magnetic anastomosis.Conclusion The magnetic compression anastomat is a safe and effective device of sutureless intestinal anastomosis in canine models.

Rejection of Permacol~ mesh used in abdominal wall repair:A case report

Permacol mesh has shown promise when used in abdominal wall repair,especially in the presence of a contaminated surgical field.This biomaterial,derived from porcine dermis collagen,has proposed advantages over synthetic materials due to increased biocompatibility and reduced foreign body reaction within human tissues.However,we present a case report describing a patient who displayed rejection to a Permacol mesh when used in the repair of abdominal wound dehiscence following an emergency laparotomy.Review of the English language literature using PubMed and Medline, showed only two previously published cases of explantation of Permacoldue to sepsis or wound breakdown. The authors believe this is the first case of severe foreign body reaction leading to rejection of Permacol.Both animal and human studies show conflicting evidence of biocompatibility.There are several reports of successful use of Permacolto repair complex incisional herniae or abdominal walls in the presence of significant contamination.It appears from the literature that Permacolis a promising material,but as we have demonstrated,it has the potential to evoke a foreign body reaction and rejection in certain subjects.

Current research progress on cell membrane decorated macroscopic biomaterials

The cell membranes,derived from natural sources,possesses unique physicochemical properties of phospholipid bilayers and biological functionalities of membrane proteins.This makes it an ideal biomimetic coating to enhance the in vivo circulation and retention time of micro/nanodrug carriers,provide targeted drug delivery effects,and neutralize bacterial toxins.Notably,recent studies have successfully coated various types of cell membranes onto the surfaces of macroscopic materials,such as electrospun fiber scaffolds and decellularized matrices,to promote tissue repair,modulate host responses to foreign materials,and alleviate inflammation.This review comprehensively summarizes the latest research progress in the modification of macroscopic biomaterials with cell membranes.The insights provided aim to serve as a valuable reference for the preparation of cell membrane biomimetic coatings and their applications in the field of tissue repair.

A pore way to heal and regenerate:21st century thinking on biocompatibility

This article raises central questions about the definition of biocompatibility,and also about how we assess biocompatibility.We start with the observation that a porous polymer where every pore is spherical,40 microns in diameter and interconnected,can heal into vascularized tissues with little or no fibrosis and good restoration of vascularity(i.e.,little or no foreign body reaction).The same polymer in solid form will trigger the classic foreign body reaction characterized by a dense,collagenous foreign body capsule and low vascularity.A widely used definition of biocompatibility is‘the ability of a material to perform with an appropriate host response in a specific application’.With precision-porous polymers,in direct comparison with the same polymer in solid form,we have the same material,in the same application,with two entirely different biological reactions.Can both reactions be‘biocompatible?’This conundrum will be elaborated upon and proposals will be made for future considerations and measurement of biocompatibility.