Applicatoin of chitosan-based hydrogel in oral tissue engineering. / å£³èšç³–åŸºæ°´å‡èƒ¶åœ¨å£è ”ç»„ç»‡å·¥ç¨‹ä¸­çš„åº”ç”¨.

Pulpitis, periodontitis, jaw bone defect, and temporomandibular joint damage are common oral and maxillofacial diseases in clinic, but traditional treatments are unable to restore the structure and function of the injured tissues. Due to their good biocompatibility, biodegradability, antioxidant effect, anti-inflammatory activity, and broad-spectrum antimicrobial property, chitosan-based hydrogels have shown broad applicable prospects in the field of oral tissue engineering. Quaternization, carboxymethylation, and sulfonation are common chemical modification strategies to improve the physicochemical properties and biological functions of chitosan-based hydrogels, while the construction of hydrogel composite systems via carrying porous microspheres or nanoparticles can achieve local sequential delivery of diverse drugs or bioactive factors, laying a solid foundation for the well-organized regeneration of defective tissues. Chemical cross-linking is commonly employed to fabricate irreversible permanent chitosan gels, and physical cross-linking enables the formation of reversible gel networks. Representing suitable scaffold biomaterials, several chitosan-based hydrogels transplanted with stem cells, growth factors or exosomes have been used in an attempt to regenerate oral soft and hard tissues. Currently, remarkable advances have been made in promoting the regeneration of pulp-dentin complex, cementum-periodontium-alveolar bone complex, jaw bone, and cartilage. However, the clinical translation of chitosan-based hydrogels still encounters multiple challenges. In future, more in vivo clinical exploration under the conditions of oral complex microenvironments should be performed, and the combined application of chitosan-based hydrogels and a variety of bioactive factors, biomaterials, and state-of-the-art biotechnologies can be pursued in order to realize multifaceted complete regeneration of oral tissue.

Influencing factors of pulp-dentin complex regeneration and related biological strategies.

Regenerative endodontic therapy (RET) utilizing tissue engineering approach can promote the regeneration of pulp-dentin complex to restore pulp vascularization, neuralization, immune function and tubular dentin, therefore the regenerated pulp-dentin complex will have normal function. Multiple factors may significantly affect the efficacy of RET, including stem cells, biosignaling molecules and biomaterial scaffolds. Stem cells derived from dental tissues (such as dental pulp stem cells) exhibit certain advantages in RET. Combined application of multiple signaling molecules and activation of signal transduction pathways such as Wnt/ß-catenin and BMP/Smad play pivotal roles in enhancing the potential of stem cell migration, proliferation, odontoblastic differentiation, and nerve and blood vessel regeneration. Biomaterials suitable for RET include naturally-derived materials and artificially synthetic materials. Artificially synthetic materials should imitate natural tissues for biomimetic modification in order to realize the temporal and spatial regulation of pulp-dentin complex regeneration. The realization of pulp-dentin complex regeneration depends on two strategies: stem cell transplantation and stem cell homing. Stem cell homing strategy does not require the isolation and culture of stem cells in vitro, so is better for clinical application. However, in order to achieve the true regeneration of pulp-dentin complex, problems related to improving the success rate of stem cell homing and promoting their proliferation and differentiation need to be solved. This article reviews the influencing factors of pulp-dentin complex regeneration and related biological strategies, and discusses the future research direction of RET, to provide reference for clinical translation and application of RET.

Different concentrations of C5a affect human dental pulp mesenchymal stem cells differentiation.

BACKGROUND: During the process of deep decay, when decay approaches the pulp, an immune response is triggered inside the pulp, which activates the complement cascade. The effect of complement component 5a (C5a) on the differentiation of dental pulp mesenchymal stem cells (DPSCs) is related to dentin reparation. The aim of the present study was to stimulate DPSCs with different concentrations of C5a and evaluate the differentiation of odontoblasts using dentin sialoprotein (DSP). METHODS: DPSCs were divided into the following six groups: (i) Control; (ii) DPSCs treated with 50 ng/ml C5a; (iii) DPSCs treated with 100 ng/ml C5a; (iv) DPSCs treated with 200 ng/ml C5a; (v) DPSCs treated with 300 ng/ml C5a; and (vi) DPSCs treated with 400 ng/ml C5a. Flow cytometry and multilineage differentiation potential were used to identify DPSCs. Mineralization induction, Real-time PCR and Western blot were conducted to evaluate the differentiation of odontoblast in the 6 groups. RESULT: DPSCs can express mesenchymal stem cell markers, including CD105, CD90, CD73 and, a less common marker, mesenchymal stromal cell antigen-1. In addition, DPSCs can differentiate into adipocytes, neurocytes, chondrocytes and odontoblasts. All six groups formed mineralized nodules after 28 days of culture. Reverse transcription-quantitative PCR and western blotting indicated that the high concentration C5a groups expressed higher DSP levels and promoted DPSC differentiation, whereas the low concentration C5a groups displayed an inhibitory effect. CONCLUSION: In this study, the increasing concentration of C5a, which accompanies the immune process in the dental pulp, has demonstrated an enhancing effect on odontoblast differentiation at higher C5a concentrations in vitro.

Parenchymal and stromal tissue regeneration of tooth organ by pivotal signals reinstated in decellularized matrix.

Cells are transplanted to regenerate an organs' parenchyma, but how transplanted parenchymal cells induce stromal regeneration is elusive. Despite the common use of a decellularized matrix, little is known as to the pivotal signals that must be restored for tissue or organ regeneration. We report that Alx3, a developmentally important gene, orchestrated adult parenchymal and stromal regeneration by directly transactivating Wnt3a and vascular endothelial growth factor. In contrast to the modest parenchyma formed by native adult progenitors, Alx3-restored cells in decellularized scaffolds not only produced vascularized stroma that involved vascular endothelial growth factor signalling, but also parenchymal dentin via the Wnt/ß-catenin pathway. In an orthotopic large-animal model following parenchyma and stroma ablation, Wnt3a-recruited endogenous cells regenerated neurovascular stroma and differentiated into parenchymal odontoblast-like cells that extended the processes into newly formed dentin with a structure-mechanical equivalency to native dentin. Thus, the Alx3-Wnt3a axis enables postnatal progenitors with a modest innate regenerative capacity to regenerate adult tissues. Depleted signals in the decellularized matrix may be reinstated by a developmentally pivotal gene or corresponding protein.

Risk Factors Associated with Inadequate Bowel Preparation in Patients with Functional Constipation.

BACKGROUND: Constipation is a common reason of poor bowel preparation, which negatively influences the quality of colonoscopy. Risk factors for inadequate bowel preparation in constipated patients remain unclear. AIMS: This study aimed to investigate the high-risk factors that might influence the quality of bowel preparation in patients with functional constipation. METHODS: Consecutive patients with functional constipation who underwent colonoscopy between June 2016 and April 2017 were enrolled. A standard split dose of 4 l polyethylene glycol was used for bowel preparation. Patient- and procedure-related parameters were recorded. The primary outcome was an adequate rate of bowel preparation. Risk factors for inadequate bowel preparation were screened by multivariate logistic regression analysis. RESULTS: A total of 199 patients were included. Adequate bowel preparation was found in 62.8% (125/199) of patients. At multivariate analysis, Bristol stool form scale (BSFS) 1 [odds ratio (OR) 2.73, 95% confidence interval (CI) 1.26-5.90; P = 0.011], rectal pain score during defecation < 2 (OR 4.14, 95% CI 1.22-13.97; P = 0.022), and starting-to-defecation interval ≥ 4 h (OR 3.83, 95% CI 1.34-10.91; P = 0.012) were risk factors for inadequate bowel preparation in patients with constipation. For patients with no, 1, 2, or 3 risk factors, the rates of inadequate bowel preparation were 11%, 23%, 49%, and 65%, respectively. CONCLUSIONS: With the standard preparation regime, > 1/3 of patients with functional constipation had inadequate bowel cleansing. BSFS 1, rectal pain score during defecation < 2, and starting-to-defecation interval ≥ 4 h were identified as independent risk factors for inadequate bowel preparation in constipated patients. TRIAL REGISTRATION: ClinicalTrials.gov number NCT02842411.

A Dean-flow-coupled interfacial viscoelastic fluid for microparticle separation applied in a cell smear method.

We propose a novel microfluidic device for continuous, label-free and size-selective particle separation. The process consists of two stages: the particle separation based on the pre-focus of sheath flow and the size-selective interface between a Newtonian sample fluid and non-Newtonian poly(ethylene oxide) (PEO) solution (1st stage), and separation distance expansion due to the contraction-expansion structure (2nd stage). The force balance has been analyzed to explore the mechanism and the factors in the particle migration. In the 1st stage, the inertial lift force and the interfacial elastic lift force are a couple of counter forces which only allow the target particles to penetrate the interface. By controlling the flow rate ratio and the PEO concentration, all unwanted particles can be confined to the sample layer. In the 2nd stage, the elastic lift force is used to counteract the inertial lift force, which increases the predomination of the Dean drag force in the lateral migration of the target particles. We conclude that the separation distance is not monotonically increasing with the elastic lift force but peaks at 50-150 ppm. Thus, an optimal parameter for particle separation in our device is obtained. Compared to a similar method without the 2nd stage and the same device without the 1st stage, the distance between the target particles and the unwanted particles could increase by approximately 35.8% and 101.2%, respectively. Finally, a sensitive, time saving and no background-interfering cell smear method is approved to diagnose the malignant pleural effusion efficiently.

Adult-onset demyelinating neuropathy associated with FBLN5 gene mutation.

Rare forms of autosomal-dominant Charcot-Marie-Tooth disease (AD-CMT) may be associated with mutations in Fibulin-5 (FBLN5) as AD-CMT is genetically heterogeneous. Here, we report the first pathological study of an Asian family. The proband was a 46-year-old man with slowly progressive distal numbness and weakness for 12 years. He had a history of diabetes mellitus for 12 years. His mother was 81 years old and had mild polyneuropathy. His 16-year-old daughter was asymptomatic. The nerve conduction velocities (NCVs) and compound muscular action potential (CMAP) amplitudes were moderately to severely reduced in the proband, and moderately reduced in his daughter and mother. A sensory response could not be elicited in the proband and was moderately to severely decreased in the daughter and mother. Nerve ultrasound indicated a general enlargement of the peripheral nerves in the proband, daughter, and mother. A sural nerve biopsy from the proband demonstrated a pronounced depletion of myelinated fibers, thin myelinated fibers, and onion-bulb formations. A reported heterozygous mutation of c.1117C>T in FBLN5 was identified in the proband, mother, and daughter. These findings confirm a novel subtype of AD-CMT 1 due to a mutation in the FBLN5 gene.
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[Application of quality by design in granulation process for ginkgo leaf tablet (⠣)： influence and control of raw materials' quality variation].

Raw materials' quality variation could affect the quality consistency of product and the clinical efficacy. In this paper, the high shear wet granulation (HSWG) process of the ginkgo leaf tablet was taken as the research object. Ginkgo biloba extracts and excipients microcrystalline cellulose collected from various sources and batches were used to simulate raw materials' quality variation. Real-time torque was recorded to analyze the viscosity of the wetting mass, and then by combining with physical fingerprint, the impact of physical quality variation of powders on granule properties could be investigated. Based on regime map thesis, whether the granules' nucleation mode was in mechanical dispersion regime was determined by calculating dimensionless parameters, which would lead to the unstable output in considerations of granule yield ratio and particle size distribution (PSD) curve. The orthogonal partial least square (OPLS) model was adopted to build the relationship between the micromeritic properties and the mediangranule size (D50) of Ginkgo biloba granules and then the critical material attributes (CMAs) were screened by variable importance in the projection (VIP) indexes. The results demonstrated that the properties of powders including hygroscopicity, angle of repose, Hausner ratio, Carr index, D10 and loss on drying affected the granule size. Besides, Ginkgo biloba granules were compressed into tablets. In view of tensile strength analysis, the raw materials' quality variation did not result in decrease of tensile strength of the ginkgo leaf tablets. The design space of critical quality attributes (CQAs) and the process design space which could cope with raw materials' quality variation were proved to be robust..

Association Between Helicobacter pylori Infection and Risk of Periodontal Diseases in Han Chinese: A Case-Control Study.

BACKGROUND: This study was performed to test the association between Helicobacter pylori (HP) and periodontal disease (PD). MATERIAL/METHODS: This was a case-control study in a comprehensive hospital, including all patients with newly diagnosed PD between 2012 and 2014 as cases and all patients without PD as controls, thorough periodontal examinations. Those who tested positive for HP were examined by means of polymerase chain reaction. Single and multivariate logistic regression was used to analyze the data using SPSS 19.0 software. RESULTS: This case-control study included 212 Han Chinese non-smoking adults. The results indicated that HP-positive status significantly increased the risk of PD (2.63 times higher (odds ratio [OR]=2.63; 95% confidence interval [CI]=1.48-4.67). After adjustment for age, sex, level of education, physical exercise, body mass index, and history of alcohol and diabetes mellitus, this association remained significantly (OR=2.82, 95% CI=1.55-5.13). CONCLUSIONS: PD might be associated with HP infection in adults and HP infection may be a significant and independent risk factor for PD.

[Near infrared spectrum monitoring of scale up process for macroporous resin purification of Grardeniae extract].

To establish a fast detection method during the purifying process of the extracts from Grardeniae using macroporous resin based on near infrared spectroscopy. First, the ethanol eluent was collected from the purification process of small size sample; and near infrared (NIR) spectrum was collected. Then the content of the geniposide was determined by HPLC method, and partial least squares (PLS) method was used to establish the quantitative model to predict the content of geniposide by NIR spectrum. This model was used to supervise the changes of geniposide concentrations in ethanol eluent during medium scale process. Experimental results showed that the NIR small scale model can accurately predict the concentrations of geniposide in the production process of medium scale. However, with the proceeding of batch processes, the prediction performance of the model was decreased, so model updating method was employed to maintain the model. After twice updates, the NIR quantitative model can accurately predict the concentrations of the geniposide during medium scale process. Therefore, through model updates, the established NIR quantitative model can be applied in different scales of macroporous resin purification processes, to improve the data utilization efficiency of small scale process and save the cost of rebuilding the quantitative model of medium scale.

[Quality by design based high shear wet granulation process development for the microcrystalline cellulose].

The design space of the high shear wet granulation process was established and validated within the framework of quality by design (QbD). The system of microcrystalline cellulose-de-ioned water was used in this study. The median granule size and bulk density of granules were identified as critical quality attributes. Plackeet-Burmann experimental design was used to screen these factors as follows: dry mixing time, the impeller and chopper speed of dry mixing, water amount, water addition time, wet massing time, the impeller and chopper speed of wet massing and drying time. And the optimization was implemented with the central composite experimental design based on screened critical process parameters. The design space of the high shear wet granulation process was established based on the quadratic polynomial regression model. Since the P-values of both models were less than 0.05 and values of lack of fit were more than 0.1, the relationship between critical quality attributes and critical process parameters could be well described by the two models. The reliability of design space, illustrated by overlay plot, was improved with the addition of 95% confidence interval. For those granules whose process parameters were in the design space, the granule size could be controlled within 250 to 355 µm, and the bulk density could be controlled within a range of 0.4 to 0.6 g x cm(-3). The robustness and flexibility of the high shear wet granulation process have been enhanced via the establishment of the design space based on the QbD concept.

Regenerative endodontic therapy: From laboratory bench to clinical practice.

BACKGROUND: Maintaining the vitality and functionality of dental pulp is paramount for tooth integrity, longevity, and homeostasis. Aiming to treat irreversible pulpitis and necrosis, there has been a paradigm shift from conventional root canal treatment towards regenerative endodontic therapy. AIM OF REVIEW: This extensive and multipart review presents crucial laboratory and practical issues related to pulp-dentin complex regeneration aimed towards advancing clinical translation of regenerative endodontic therapy and enhancing human life quality. KEY SCIENTIFIC CONCEPTS OF REVIEW: In this multipart review paper, we first present a panorama of emerging potential tissue engineering strategies for pulp-dentin complex regeneration from cell transplantation and cell homing perspectives, emphasizing the critical regenerative components of stem cells, biomaterials, and conducive microenvironments. Then, this review provides details about current clinically practiced pulp regenerative/reparative approaches, including direct pulp capping and root revascularization, with a specific focus on the remaining hurdles and bright prospects in developing such therapies. Next, special attention was devoted to discussing the innovative biomimetic perspectives opened in establishing functional tissues by employing exosomes and cell aggregates, which will benefit the clinical translation of dental pulp engineering protocols. Finally, we summarize careful consideration that should be given to basic research and clinical applications of regenerative endodontics. In particular, this review article highlights significant challenges associated with residual infection and inflammation and identifies future insightful directions in creating antibacterial and immunomodulatory microenvironments so that clinicians and researchers can comprehensively understand crucial clinical aspects of regenerative endodontic procedures.

Multifunctional Exosomes Derived from M2 Macrophages with Enhanced Odontogenesis, Neurogenesis and Angiogenesis for Regenerative Endodontic Therapy: An In Vitro and In Vivo Investigation.

INTRODUCTION: Exosomes derived from M2 macrophages (M2-Exos) exhibit tremendous potential for inducing tissue repair and regeneration. Herein, this study was designed to elucidate the biological roles of M2-Exos in regenerative endodontic therapy (RET) compared with exosomes from M1 macrophages (M1-Exos). METHODS: The internalization of M1-Exos and M2-Exos by dental pulp stem cells (DPSCs) and human umbilical vein endothelial cells (HUVECs) was detected by uptake assay. The effects of M1-Exos and M2-Exos on DPSC and HUVEC behaviors, including migration, proliferation, odonto/osteogenesis, neurogenesis, and angiogenesis were determined in vitro. Then, Matrigel plugs incorporating M2-Exos were transplanted subcutaneously into nude mice. Immunostaining for vascular endothelial growth factor (VEGF) and CD31 was performed to validate capillary-like networks. RESULTS: M1-Exos and M2-Exos were effectively absorbed by DPSCs and HUVECs. Compared with M1-Exos, M2-Exos considerably facilitated the proliferation and migration of DPSCs and HUVECs. Furthermore, M2-Exos robustly promoted ALP activity, mineral nodule deposition, and the odonto/osteogenic marker expression of DPSCs, indicating the powerful odonto/osteogenic potential of M2-Exos. In sharp contrast with M1-Exos, which inhibited the neurogenic capacity of DPSCs, M2-Exos contributed to a significantly augmented expression of neurogenic genes and the stronger immunostaining of Nestin. Consistent with remarkably enhanced angiogenic markers and tubular structure formation in DPSCs and HUVECs in vitro, the employment of M2-Exos gave rise to more abundant vascular networks, dramatically higher VEGF expression, and widely spread CD31+ tubular lumens in vivo, supporting the enormous pro-angiogenic capability of M2-Exos. CONCLUSIONS: The multifaceted roles of M2-Exos in ameliorating DPSC and HUVEC functions potentially contribute to complete functional pulp-dentin complex regeneration.

Exosomes as Promising Therapeutic Tools for Regenerative Endodontic Therapy.

Pulpitis is a common and frequent disease in dental clinics. Although vital pulp therapy and root canal treatment can stop the progression of inflammation, they do not allow for genuine structural regeneration and functional reconstruction of the pulp-dentin complex. In recent years, with the development of tissue engineering and regenerative medicine, research on stem cell-based regenerative endodontic therapy (RET) has achieved satisfactory preliminary results, significantly enhancing its clinical translational prospects. As one of the crucial paracrine effectors, the roles and functions of exosomes in pulp-dentin complex regeneration have gained considerable attention. Due to their advantages of cost-effectiveness, extensive sources, favorable biocompatibility, and high safety, exosomes are considered promising therapeutic tools to promote dental pulp regeneration. Accordingly, in this article, we first focus on the biological properties of exosomes, including their biogenesis, uptake, isolation, and characterization. Then, from the perspectives of cell proliferation, migration, odontogenesis, angiogenesis, and neurogenesis, we aim to reveal the roles and mechanisms of exosomes involved in regenerative endodontics. Lastly, immense efforts are made to illustrate the clinical strategies and influencing factors of exosomes applied in dental pulp regeneration, such as types of parental cells, culture conditions of parent cells, exosome concentrations, and scaffold materials, in an attempt to lay a solid foundation for exploring and facilitating the therapeutic strategy of exosome-based regenerative endodontic procedures.

Comparative evaluation of an innovative deflectable percutaneous kyphoplasty versus conventional bilateral percutaneous kyphoplasty for osteoporotic vertebral compression fractures: a prospective, randomized and controlled trial.

BACKGROUND CONTEXT: Osteoporotic vertebral compression fractures (OVCFs) can be treated with percutaneous kyphoplasty (PKP). In contrast to conventional PKP, the novel deflectable percutaneous kyphoplasty (DPKP), is a unilateral transpedicular approach procedure allowing a similar bilateral puncture effect, which owes to the deflectable curved bone expander creating a transcentral line cavity to achieve uniform distribution of cement and biomechanical balance while reducing operative time and radiation exposure. PURPOSE: The purpose of this study was to prospectively compare and evaluate an innovative surgical procedure, DPKP, versus conventional bilateral percutaneous kyphoplasty (BPKP). STUDY DESIGN: This is a prospective randomized controlled trial (RCT). SAMPLE: The totality of the participants (n=90) suffering from OVCFs between May 2019 and October 2020, were randomized by SAS 9.3 to generate a block randomization sequence, which was utilized to randomize the groups in a 1:1 ratio, assigned to the DPKP group (n=45) and the BPKP group (n=45) to undergo accordingly procedures. OUTCOME MEASURES: The primary outcome was the total operative time. The secondary outcomes included: comparative assessment of visual analog scale (VAS) scores, Oswestry disability index (ODI), kyphosis angle (KA), anterior border height (AH) of the injured vertebra, frequency of intraoperative X-ray fluoroscopy, the injection volume, distribution pattern and leakage rate of bone cement. METHODS: All subjects underwent assessment by at least one senior orthopedist and radiologist for the VAS scores, ODI, KA, AH of the injured vertebra, total operative time, the injection volume, distribution pattern, leakage rate of bone cement at preoperative and 24 hours, 6 months, and 1 year postoperatively. Inclusion criteria for subjects in this prospective study were as follows: (1) 60 < age < 80 years old; (2) preoperative spinal X-ray, CT, and MRI confirmed as single-segment, fresh thoracolumbar OVCFs (T5-L5, 15% < collapse < 80%); MRI shows low signal on T1-WI and high signal on T2-WI, especially with STIR high signal characterized by vertebral edema; (3) painful OVCFs refractory to medical treatment, 2 weeks < Symptom duration < 3 months;(4) With significant physical signs of local tenderness; (5) T score of bone mineral density (BMD) < -2.5. RESULTS: The total operative time was significantly reduced in the DPKP group (43.3±19.58 minutes, 95% CI: 37.23-49.37) compared to the BPKP group (55.16±11.56 minutes, 95% CI: 51.78-58.54) (p<.001). Compared to the BPKP group (frequency of intraoperative X-ray fluoroscopy: 43.42±8.64, 95% CI: 40.90-45.95; the volume of bone cement injected: 5.56±0.85 mL, 95% CI: 5.31-5.81), the frequency of intraoperative X-ray fluoroscopy (30.05±17.41, 95% CI: 24.66-35.45) and volume of bone cement injected (5.08±0.97 mL, 95% CI: 4.78-5.38) significantly reduced in the DPKP group compared to the (p<.001). In addition, compared to the preoperative period, both groups showed significant improvements in the postoperative VAS scores, ODI, KA, and AH (p<.001), but there was no statistical difference between the DPKP and BPKP groups (p>.05) at any time-point. Interestingly, although without statistical differences, a tendency towards a lower rate of bone cement leakage was observed in the DPKP group. CONCLUSION: Our study results indicate that the innovative DPKP is as safe and effective as BPKP in relieving pain, improving the patient's quality of life, and reconstructing vertebral body height. Particularly, DPKP did reduce operative time and radiation exposure compared to BPKP, which correlated with unilateral and bilateral exposure procedures. Moreover, the final cement distribution was less predictable in DPKP, and further studies are warranted to clarify the advantages of DPKP versus conventional unilateral percutaneous kyphoplasty (UPKP) and BPKP.

Exosomes derived from human dental pulp stem cells increase flap survival with ischemia-reperfusion injuries.

Aim: To investigate the effect of hDPSC-Exos in flap I/R injury, a condition in which tissue damage increases after blood flow is restored to the flap after ischemia. Materials & methods: HUVECs were used to investigate the influences and mechanisms of hDPSC-Exos on cell proliferation and migration. A rat model was established to verify the role of hDPSC-Exos in flap I/R injuries in vivo. Results: hDPSC-Exos promoted the proliferation, migration and tube formation of HUVECs in a dose-dependent way by activating PI3K/AKT signaling pathway, and improved the survival and microvessel density of the flap and suppressed epithelial cell apoptosis. Conclusion: hDPSC-Exos can enhance flap repair after I/R injury. This process may be mediated by the activation of PI3K/AKT signaling pathway.

Skin flap transplantation is one of the most important methods of repairing refractory wounds and organ reconstruction. I/R injury and insufficiency of neovascularization significantly affect the survival of flaps. Human dental pulp stem cells (hDPSCs) are a type of mesenchymal stem cells (MSCs) present in dental pulp tissue that have attracted increasing attention. They can play a repair role in a variety of ischemic injuries and neovascularization. Exosomes are important paracrine mediators between MSCs and target cells, containing a variety of proteins, mRNA and miRNA. Recent studies have shown that some exosomes derived from MSCs can improve I/R injury, promote angiogenesis and inhibit apoptosis. This study confirmed that hDPSC-Exos could promote the proliferation, migration and tubule formation of vein endothelial cells in a dose-dependent manner. Inhibition of PI3K/AKT signaling pathway can reduce the above promoting effects, suggesting that these processes may depend on the activation of PI3K/AKT signaling pathway. In the rat model, hDPSC-Exos can significantly improve the survival rate and microvessel density of flaps, and inhibit epithelial cell apoptosis.

An electrospun scaffold functionalized with a ROS-scavenging hydrogel stimulates ocular wound healing.

Ocular alkali burn is a serious ophthalmic emergency. Highly penetrative alkalis cause strong inflammatory responses leading to persistent epithelial defects, acute corneal perforation and severe scarring, and thereby persistent pain, loss of vision and cicatricial sequelae. Early and effective anti-inflammation management is vital in reducing the severity of injury. In this study, a double network biomaterial was prepared by compounding electrospinning nanofibres of thioketal-containing polyurethane (PUTK) with a reactive oxygen species (ROS)-scavenging hydrogel (RH) fabricated by crosslinking poly(poly(ethylene glycol) methyl ether methacrylate-co-glycidyl methacrylate) with thioketal diamine and 3,3'-dithiobis(propionohydrazide). The developed PUTK/RH patch exhibited good transparency, high tensile strength and increased hydrophilicity. Most importantly, it demonstrated strong antioxidant activity against H2O2 and 2,2-di(4-tert-octylphenyl)-1-picryl-hydrazyl (DPPH). Next, a rat corneal alkali burn model was established, and the PUTK/RH patch was transplanted on the injured cornea. Reduced inflammatory cell infiltration was revealed by confocal microscopy, and lower expression levels of genes relative to inflammation, vascularization and scarring were identified by qRT-PCR and western blot. Fluorescein sodium dyeing, hematoxylin and eosin (H&E) staining and immunohistochemical staining confirmed that the PUTK/RH patch could accelerate corneal wound healing by inhibiting inflammation, promoting epithelial regeneration and decreasing scar formation. STATEMENT OF SIGNIFICANCE: Ocular alkali burn is a serious ophthalmic emergency, characterized with persistent inflammation and irreversible vision loss. Oxidative stress is the main pathological process at the acute inflammatory stage, during which combined use of glucocorticoids and amniotic membrane transplantation is the most widely accepted treatment. In this study, we fabricated a polyurethane electrospun nanofiber membrane functionalized with a ROS-scavenging hydrogel. This composite patch could be a promising amniotic membrane substitute, possessing with a transparent appearance, elasticity and anti-inflammation effect. It could be easily transplanted onto the alkali-burned corneas, resulting in a significant inhibition of stromal inflammation and accelerating the recovery of corneal transparency. The conception of ROS-scavenging wound patch may offer a new way for ocular alkali burn.

The poor oral health status of former heroin users treated with methadone in a Chinese city.

BACKGROUND: There have been few studies conducted on the oral health status of illegal drug users in China, affecting the development of preventive and therapeutic approaches. The aim of the present study was to investigate and analyze the oral health status of former heroin users treated with methadone in Chengdu, the capital of Sichuan Province in southwestern China. MATERIAL/METHODS: The presence of caries (decayed tooth and root), missing teeth, residual roots, dental prosthetic restoration and periodontal health were investigated in 445 former heroin users treated with methadone (317 males and 128 females). Their ages ranged from 20 to 59 years old. RESULTS: Among the study subjects, the prevalence of decayed/filled teeth was 64.72%, and the mean of decayed/filled teeth score was 2.92. The prevalence of decayed/filled roots was 21.80%, and the mean of decayed/filled roots score was 0.62. The prevalence of missing teeth was 31.46%, and the mean missing teeth score was 0.62. The prevalence of residual roots was 42.02%, with a mean score of 1.06. The rates of gingival bleeding, calculus, shallow pockets periodontal pocket, and deep periodontal pocket were 99.55%, 96.63%, 30.34%, and 2.70%, respectively. CONCLUSIONS: The oral health status among the studied former heroin users in Chengdu was poorer than the general population. Better dental care for the former heroin users is needed to promote their oral health.

Cytoprotective effect of hyaluronic acid and hydroxypropyl methylcellulose against DNA damage induced by thimerosal in Chang conjunctival cells.

BACKGROUND: To investigate genotoxicity of the preservative thimerosal (Thi), and the cytoprotective and antioxidant effects of hyaluronic Acid (HA) and hydroxypropyl methylcellulose (HPMC) on Chang conjunctival cells. METHOD: Cells were divided into three groups. One group was exposed to Thi at various concentrations (0.00001 %∼0.001 %) for 30 min; the other two groups were pretreated with 0.3 % HA or 0.3 % HPMC for 30 min before the Thi exposure. After cell viability was evaluated, alkaline comet assay and detection of the phosphorylated form of the histone variant H2AX (γH2AX) foci were used to determine DNA damage. Reactive oxygen species (ROS) production was assessed by the fluorescent probe, 2', 7'-dichlorodihydrofluorescein diacetate (DCFH-DA). RESULTS: A significant change of cell viability was observed after exposure to 0.001 % Thi for 30 min. DNA single- and double-strand breaks were significantly increased in a dose-dependent manner with Thi exposure. In addition, intracellular ROS induced by Thi was dose-dependent, except at 0.001 % less ROS was induced than at 0.0005 %. However, cells pretreated with 0.3 % HA or 0.3 % HPMC showed significantly increased cell survival, decreased DNA damage, and decreased ROS production compared to cells exposed to Thi alone. Pretreatment with 0.3 % HA was found to be even more protective than 0.3 % HPMC. CONCLUSION: Thi can induce DNA damage in human conjunctival epithelial cells, probably due to oxidative stress. HA and HPMC are protective agents that have antioxidant properties and can decrease DNA damage induced by Thi. Pretreatment of 0.3 % HA may be more protective of the ocular surface than 0.3 % HPMC.

Synthesis, structure, and photoluminescent properties of metal-organic coordination polymers assembled with bithiophenedicarboxylic acid.

Four novel metal-organic coordination polymers with the formulas Mn(3)(btdc)(3)(DMF)(4) (1), Co(btdc)(DMF)(3) (2), Zn(btdc)(DMF)(3) (3), and Zn(btdc)(4,4'-bpy)(0.5) (4), where H(2)btdc = 2,2'-bithiophene-5,5'-dicarboxylic acid, DMF = N,N'-dimethylformamide, and 4,4'-bpy = 4,4'-bipyridine, have been successfully synthesized. Crystal 1 with Mn(2+) as the cation features a three-dimensional (3D) infinite framework built from trimanganese clusters, and crystals 2 and 3 with Co(2+) and Zn(2+), respectively, as the cation both have one-dimensional zigzag polymeric coordination chains. Crystal 4 synthesized using a mixture of 4,4'-bpy and H(2)btdc exhibits a triply interpenetrating 3D framework built from a dizinc paddlewheel second building unit with a distorted primitive cubic single net. The results of UV/vis spectra indicate that metal binding does not disturb the detailed electronic structure of the ligand. We also demonstrate that Zn(2+) can greatly enhance the luminescence emission of the H(2)btdc ligand, and the emission intensity of crystal 4 is almost 20 times higher than that of the free H(2)btdc ligand. Steady-state and time-resolved spectroscopic measurement reveal that the more rigid environment of the btdc ligand can stabilize the highly excited long-lived states in metal-organic frameworks (MOFs), which thus greatly changes the emission properties of MOFs.