Neurotrophic effects of dental pulp stem cells in repair of peripheral nerve after crush injury

BACKGROUND Nerve diseases and injuries,which are usually accompanied by motor or sensory dysfunction and disorder,impose a heavy burden upon patients and greatly reduce their quality of life.Dental pulp stem cells(DPSCs),derived from the neural crest,have many characteristics that are similar to those of neural cells,indicating that they can be an ideal source for neural repair.AIM To explore the potential roles and molecular mechanisms of DPSCs in crushed nerve recovery.METHODS DPSCs were isolated,cultured,and identified by multilineage differentiation and flow cytometry.Western blot and immunofluorescent staining were applied to analyze the expression levels of neurotrophic proteins in DPSCs after neural induction.Then,we collected the secretions of DPSCs.We analyzed their effects on RSC96 cell proliferation and migration by CCK8 and transwell assays.Finally,we generated a sciatic nerve crush injury model in vivo and used the sciatic function index,walking track analysis,muscle weight,and hematoxylin&eosin(H&E)staining to further evaluate the nerve repair ability of DPSCs.RESULTS DPSCs highly expressed several specific neural markers,including GFAP,S100,Nestin,P75,and NF200,and were inclined toward neural differentiation.Furthermore,neural-induced DPSCs(N-DPSCs)could express neurotrophic factors,including NGF,BDNF,and GDNF.The secretions of N-DPSCs could enhance the proliferation and migration of Schwann cells.In vivo,both DPSC and N-DPSC implants alleviated gastrocnemius muscle atrophy.However,in terms of anatomy and motor function,as shown by H&E staining,immunofluorescent staining,and walking track analyses,the repair effects of N-DPSCs were more sustained,potent,and effective than those of DPSCs and the controls.CONCLUSION In summary,this study demonstrated that DPSCs are inclined to differentiate into neural cells.N-DPSCs express neurotrophic proteins that could enhance the proliferation and migration of SCs.Furthermore,our results suggested that NDPSCs could help crushed nerves with functional recovery and anatomical repair in vivo.Thus,DPSCs or N-DPSCs could be a promising therapeutic cell source for peripheral nerve repair and regeneration.

Therapeutic potential of dental pulp stem cells and their derivatives:Insights from basic research toward clinical applications

For more than 20 years,researchers have isolated and identified postnatal dental pulp stem cells(DPSCs)from different teeth,including natal teeth,exfoliated deciduous teeth,healthy teeth,and diseased teeth.Their mesenchymal stem cell(MSC)-like immunophenotypic characteristics,high proliferation rate,potential for multidirectional differentiation and biological features were demonstrated to be superior to those of bone marrow MSCs.In addition,several main application forms of DPSCs and their derivatives have been investigated,including stem cell injections,modified stem cells,stem cell sheets and stem cell spheroids.In vitro and in vivo administration of DPSCs and their derivatives exhibited beneficial effects in various disease models of different tissues and organs.Therefore,DPSCs and their derivatives are regarded as excellent candidates for stem cell-based tissue regeneration.In this review,we aim to provide an overview of the potential application of DPSCs and their derivatives in the field of regenerative medicine.We describe the similarities and differences of DPSCs isolated from donors of different ages and health conditions.The methodologies for therapeutic administration of DPSCs and their derivatives are introduced,including single injections and the transplantation of the cells with a support,as cell sheets,or as cell spheroids.We also summarize the underlying mechanisms of the regenerative potential of DPSCs.

羧基功能化金纳米团簇的仿生结晶及其近红外磷光性质

As an interdisciplinary product,water-soluble gold nanoclusters(AuNCs)stabilized by ligands containing carboxyl(-COOH)group have garnered significant attention from synthetic chemists and biologists due to their immense potential for biomedical applications.However,revealing the crystallographic structures of-COOH-functionalized AuNCs remains a bottleneck.Herein,we successfully applied the salting-out method to obtain a series of high-quality single crystals of-COOH-functionalized Au_(25)nanoclusters and revealed their crystallographic structures.Particularly,K_(3)Au_(25)(2-Hmna)_9(mna)_6]^(-)(Au25a)protected by 2-mercaptonicotinic acid features an unprecedented tetrameric Au_(4)(SR^(S))_(3)(SR^(S,N))_(2)staple motifs surrounding the icosahedral Au_(13)kernel,breaking the traditional perception on the structure of Au_(25)(SR)_(18).Au25a exhibits a distinct near-infrared emission at 970 nm with long lifetime of 8690 ns,which have been studied by transient absorption spectroscopy and time-dependent density functional theory.This work compensates for the research gap in the experimental structure of-COOHfunctionalized AuNCs and opens up a new avenue to explore their structure-property correlations.

Correlation between Condylar Fracture Pattern after Parasymphyseal Impact and Condyle Morphological Features： A Retrospective Analysis of 107 Chinese Patients

Background： The treatment of the condylar fractures is difficult. Factors that result in the fractures are complex. The objective of this morphometric study was to investigate the relationship between condylar fracture patterns and condylar morphological characteristics. Methods： We conducted a retrospective analysis of 107 patients admitted to the West China Hospital of Stomatology for bilateral condylar fractures caused by parasymphyseal impact. The patients were divided into five groups according to the type of condylar fracture. Ten parameters were evaluated on three-dimensional （3D） reconstruction mandible models through the Mimics 16.0 （Materialize Leuven, Belgium） anthropometry toolkit. Each parameter of the 3D models was analyzed using multivariate analysis. Multinomial logistic regression analyses were used to examine the relationships between the five groups. Results： The results showed that the differences of condylar head width （M 1 ）, condylar neck width （M3）, the ratio of condylar head width to condylar anteroposterior diameter （M1/M2）, the ratio of condylar head width to condylar neck width （M1/M3）, the ratio of condylar height to ramus height （M8/M7）, and mandibular angle （M10） were statistically significant （p 〈 0.05）. Type A condylar head fractures were positively associated with M1 （compared to Type B： OR ：1.627, 95% CI： 1.123, 2.359; compared to Type C： OR = 1.705, 95% CI： 1.170, 2.484） and M1/M2 （compared to Type B： OR = 1.034, 95% CI： 0.879, 2.484）. Type B condylar head fractures were negatively associated with M l 0 （compared to Type C： OR = 0.909, 95% CI： 0.821, 1.007）. Condylar neck fractures were negatively associated with M3 （compared to condylar head： OR = 0.382, CI： 0.203, 0.720 ; compared to condylar base： OR = 0.436, 95% CI： 0.218, 0.874）, and positively associated with M 1/M3 （compared to condylar head： OR = 1.229, 95% CI： 1.063, 1.420 compared to condylar base： OR = 1.223, 95% CI： 1.034, 1.447）. Condylar base fractures were positively associated with M10 （OR = 1.095, 95% CI： 1.008, 1.189） and negatively associated with M8/M7 （OR = 0.855, 95% CI： 0.763, 0.959） as compared with condylar head fractures. Conclusions： Condylar fracture pattern is associated with the anatomical features of the condyles when a fracture occurs from parasymphyseal impact.