Decellularized adipose matrix provides an inductive microenvironment for stem cells in tissue regeneration

Stem cells play a key role in tissue regeneration due to their self-renewal and multidirectional differentiation,which are continuously regulated by signals from the extracellular matrix(ECM)microenvironment.Therefore,the unique biological and physical characteristics of the ECM are important determinants of stem cell behavior.Although the acellular ECM of specific tissues and organs(such as the skin,heart,cartilage,and lung)can mimic the natural microenvironment required for stem cell differentiation,the lack of donor sources restricts their development.With the rapid development of adipose tissue engineering,decellularized adipose matrix(DAM)has attracted much attention due to its wide range of sources and good regeneration capacity.Protocols for DAM preparation involve various physical,chemical,and biological methods.Different combinations of these methods may have different impacts on the structure and composition of DAM,which in turn interfere with the growth and differentiation of stem cells.This is a narrative review about DAM.We summarize the methods for decellularizing and sterilizing adipose tissue,and the impact of these methods on the biological and physical properties of DAM.In addition,we also analyze the application of different forms of DAM with or without stem cells in tissue regeneration(such as adipose tissue),repair(such as wounds,cartilage,bone,and nerves),in vitro bionic systems,clinical trials,and other disease research.

Implant site development using titanium plate and platelet-rich fibrin for congenitally missed maxillary lateral incisors:A case report

BACKGROUND Bone deficiency and soft tissue atrophy in the absence of maxillary lateral incisors are among the most challenging problems for implant clinicians.Autologous bone grafting is the gold standard for bone augmentation,but not without limitations.Platelet-rich fibrin(PRF),a biodegradable autologous biomaterial,has been widely used for bone and soft tissue management.Moreover,titanium plate is an advantageous barrier due to its good space-maintaining ability.However,there is a lack of literature on implant site development using titanium plate and PRF for congenitally missing maxillary lateral incisors.CASE SUMMARY The patient was a 19-year-old girl with a congenitally missing tooth(#12).She underwent implant placement and simultaneous autologous bone grafting with titanium plate and PRF.At the follow-up visit 15 d post-procedure,the vascularization of soft tissue was visible.There was no swelling or pain after the surgery.Six months postoperatively,bone regeneration was evident.Subsequently,the definitive restoration was placed,and the patient was satisfied with the esthetic outcomes.CONCLUSION Implant site development using titanium plate and PRF for congenitally missing maxillary lateral incisors is a feasible procedure.In this case,the labial bone plate was displaced but remained connected to the base bone,ensuring blood supply.The titanium plate fixed the labial bone plate and maintained the osteogenic space,while the PRF provided growth factors and leukocytes for bone and soft tissue regeneration.Furthermore,the procedure reduced the surgical complexity and adverse reactions,displaying outstanding esthetic outcomes.

Nanofiber matrix formulations for the delivery of Exendin-4 for tendon regeneration: In vitro and in vivo assessment

Tendon and ligament injuries are the most common musculoskeletal injuries,which not only impact the quality of life but result in a massive economic burden.Surgical interventions for tendon/ligament injuries utilize biological and/or engineered grafts to reconstruct damaged tissue,but these have limitations.Engineered matrices confer superior physicochemical properties over biological grafts but lack desirable bioactivity to promote tissue healing.While incorporating drugs can enhance bioactivity,large matrix surface areas and hydrophobicity can lead to uncontrolled burst release and/or incomplete release due to binding.To overcome these limitations,we evaluated the delivery of a peptide growth factor(exendin-4;Ex-4)using an enhanced nanofiber matrix in a tendon injury model.To overcome drug surface binding due to matrix hydrophobicity of poly(caprolactone)(PCL)-which would be expected to enhance cell-material interactions-we blended PCL and cellulose acetate(CA)and electrospun nanofiber matrices with fiber diameters ranging from 600 to 1000 nm.To avoid burst release and protect the drug,we encapsulated Ex-4 in the open lumen of halloysite nanotubes(HNTs),sealed the HNT tube endings with a polymer blend,and mixed Ex-4-loaded HNTs into the polymer mixture before electrospinning.This reduced burst release from~75%to~40%,but did not alter matrix morphology,fiber diameter,or tensile properties.We evaluated the bioactivity of the Ex-4 nanofiber formulation by culturing human mesenchymal stem cells(hMSCs)on matrix surfaces for 21 days and measuring tenogenic differentiation,compared with nanofiber matrices in basal media alone.Strikingly,we observed that Ex-4 nanofiber matrices accelerated the hMSC proliferation rate and elevated levels of sulfated glycosaminoglycan,tendon-related genes(Scx,Mkx,and Tnmd),and ECM-related genes(Col-Ⅰ,Col-Ⅲ,and Dcn),compared to control.We then assessed the safety and efficacy of Ex-4 nanofiber matrices in a full-thickness rat Achilles tendon defect with histology,marker expression,functional walking track analysis,and mechanical testing.Our analysis confirmed that Ex-4 nanofiber matrices enhanced tendon healing and reduced fibrocartilage formation versus nanofiber matrices alone.These findings implicate Ex-4 as a potentially valuable tool for tendon tissue engineering.