Role of dendritic cells in MYD88-mediated immune recognition and osteoinduction initiated by the implantation of biomaterials

Bone substitute material implantation has become an important treatment strategy for the repair of oral and maxillofacial bone defects.Recent studies have shown that appropriate inflammatory and immune cells are essential factors in the process of osteoinduction of bone substitute materials.Previous studies have mainly focused on innate immune cells such as macrophages.In our previous work,we found that T lymphocytes,as adaptive immune cells,are also essential in the osteoinduction procedure.As the most important antigen-presenting cell,whether dendritic cells(DCs)can recognize non-antigen biomaterials and participate in osteoinduction was still unclear.In this study,we found that surgical trauma associated with materials implantation induces necrocytosis,and this causes the release of high mobility group protein-1(HMGB1),which is adsorbed on the surface of bone substitute materials.Subsequently,HMGB1-adsorbed materials were recognized by the TLR4-MYD88-NFκB signal axis of dendritic cells,and the inflammatory response was activated.Finally,activated DCs release regeneration-related chemokines,recruit mesenchymal stem cells,and initiate the osteoinduction process.This study sheds light on the immune-regeneration process after bone substitute materials implantation,points out a potential direction for the development of bone substitute materials,and provides guidance for the development of clinical surgical methods.

EXISTENCE OF SOLUTIONS FOR THE FRACTIONAL(p,q)-LAPLACIAN PROBLEMS INVOLVING A CRITICAL SOBOLEV EXPONENT

In this article,we study the following fractional(p,q)-Laplacian equations involving the critical Sobolev exponent:(Pμ,λ){(−Δ)s 1 p u+(−Δ)s 2 q u=μ|u|q−2 u+λ|u|p−2 u+|u|p∗s 1−2 u,u=0,inΩ,in R N∖Ω,whereΩ⊂R N is a smooth and bounded domain,λ,μ>0,0<s 2<s 1<1,1<q<p<Ns 1.We establish the existence of a non-negative nontrivial weak solution to(Pμ,λ)by using the Mountain Pass Theorem.The lack of compactness associated with problems involving critical Sobolev exponents is overcome by working with certain asymptotic estimates for minimizers.

Progressive multifocal exophytic pontine glioblastoma: a case report with literature review

Multifocal pontine glioblastoma exhibiting an exophytic growth pattern in the cerebello-pontine angle(CPA) is rare.We present a case of a 5-year-old girl with consecutive neurological imaging and other clinical findings indicating progressive multifocal exophytic pontine glioblastoma.Three lesions were reported,of which two were initially presented,and one was developed 2 months later.One lesion demonstrated a progressing exophytic extension in the cistern of the left side of the CPA.The other two lesions were located and confined within the pons.Initial magnetic resonance imaging and positron emission tomography-computed tomography indicated low-grade glioma or inflammatory disease.However,2 and 3 months later,subsequent magnetic resonance spectroscopy(MRS) displayed elevated choline and depressed N-acetyl aspartate peaks compared with the peaks on the initial MRS,indicating a high-grade glioma.Subtotal resection was performed for the CPA lesion.Histopathologic examination showed discrepant features of different parts of the CPA lesion.The patient received no further chemotherapy or radiotherapy and died 2 months after surgery.The multifocal and exophytic features of this case and the heterogeneous manifestations on neurological images were rare and confusing for both diagnosis and surgical decision-making.Our case report may contribute knowledge and helpful guidance for other medical doctors.