Empagliflozin Ameliorates the Impaired Osteogenic Differentiation Ability of Adipose-Derived Stem Cells in Diabetic Osteoporosis by Activating Autophagy.

Adipose-derived stem cells (ASCs) from diabetic osteoporosis (DOP) mice showed impaired osteogenic differentiation capacity. Recent studies have shown that in addition to antidiabetic drugs, sodium-glucose co-transporter inhibitor-2 (SGLT-2), empagliflozin, can play multipotent roles through various mechanisms of action. In this study, we aimed to investigate the effects and underlying mechanisms of empagliflozin on osteogenic differentiation of ASCs in DOP mice. Our results showed that osteogenic differentiation potential and autophagy activity weakened in DOP-ASCs when compared to controls. However, empagliflozin enhanced autophagy flux by promoting the formation of autophagosomes and acidification of autophagic lysosomes, resulting in an increase in LC3-II expression and a decrease in SQSTM1 expression. Furthermore, empagliflozin contributed to the reversal of osteogenesis inhibition in DOP-ASCs induced by a diabetic microenvironment. When 3-methyladenine was used to block autophagy activity, empagliflozin could not exert its protective effect on DOP-ASCs. Nonetheless, this study demonstrated that the advent of cellular autophagy attributed to the administration of empagliflozin could ameliorate the impaired osteogenic differentiation potential of ASCs in DOP mice. This finding might be conducive to the application of ASCs transplantation for promoting bone fracture healing and bone regeneration in patients with DOP.

A Biomimetic Se-nHA/PC Composite Microsphere with Synergistic Immunomodulatory and Osteogenic Ability to Activate Bone Regeneration in Periodontitis.

Accumulation of reactive oxygen species (ROS) in periodontitis exacerbates the destruction of alveolar bone. Therefore, scavenging ROS to reshape the periodontal microenvironment, alleviate the inflammatory response and promote endogenous stem cell osteogenic differentiation may be an effective strategy for treating bone resorption in periodontitis. In this study, sericin-hydroxyapatite nanoparticles (Se-nHA NPs) are synthesized using a biomimetic mineralization method. Se-nHA NPs and proanthocyanidins (PC) are then encapsulated in sericin/sodium alginate (Se/SA) using an electrostatic injection technique to prepare Se-nHA/PC microspheres. Microspheres are effective in scavenging ROS, inhibiting the polarization of macrophages toward the M1 type, and inducing the polarization of macrophages toward the M2 type. In normal or macrophage-conditioned media, the Se-nHA/PC microspheres effectively promoted the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs). Furthermore, the Se-nHA/PC microspheres demonstrated anti-inflammatory effects in a periodontitis rat model by scavenging ROS and suppressing pro-inflammatory cytokines. The Se-nHA/PC microspheres are also distinguished by their capacity to decrease alveolar bone loss, reduce osteoclast activity, and boost osteogenic factor expression. Therefore, the biomimetic Se-nHA/PC composite microspheres have efficient ROS-scavenging, anti-inflammatory, and osteogenic abilities and can be used as a multifunctional filling material for inflammatory periodontal tissue regeneration.

Swim bladder-derived biomaterials: structures, compositions, properties, modifications, and biomedical applications.

Animal-derived biomaterials have been extensively employed in clinical practice owing to their compositional and structural similarities with those of human tissues and organs, exhibiting good mechanical properties and biocompatibility, and extensive sources. However, there is an associated risk of infection with pathogenic microorganisms after the implantation of tissues from pigs, cattle, and other mammals in humans. Therefore, researchers have begun to explore the development of non-mammalian regenerative biomaterials. Among these is the swim bladder, a fish-derived biomaterial that is rapidly used in various fields of biomedicine because of its high collagen, elastin, and polysaccharide content. However, relevant reviews on the biomedical applications of swim bladders as effective biomaterials are lacking. Therefore, based on our previous research and in-depth understanding of this field, this review describes the structures and compositions, properties, and modifications of the swim bladder, with their direct (including soft tissue repair, dural repair, cardiovascular repair, and edible and pharmaceutical fish maw) and indirect applications (including extracted collagen peptides with smaller molecular weights, and collagen or gelatin with higher molecular weights used for hydrogels, and biological adhesives or glues) in the field of biomedicine in recent years. This review provides insights into the use of swim bladders as source of biomaterial; hence, it can aid biomedicine scholars by providing directions for advancements in this field.

Methyltransferase-like 3 modulates osteogenic differentiation of adipose-derived stem cells in osteoporotic rats.

BACKGROUND: Osteoporosis (OP) is a metabolic bone disease involving reduced bone mass. Adipose-derived stem cells (ASCs) play an important role in bone regeneration. Emerging evidence suggests that methyltransferase-like 3 (METTL3) plays a significant role in bone development and metabolism. Therefore, this study investigates changes to METTL3 in the osteogenic differentiation of adipose stem cells in osteoporotic rats (OP-ASCs) and explores ways to enhance their osteogenic ability. METHODS: An animal model of osteoporosis was established by removing both ovaries in rats. Real-time PCR and western blotting were performed to detect the expression of METTL3 and bone-related molecules, including runt-related transcription factor 2 (Runx2) and osteopontin (Opn). Furthermore, alkaline phosphatase staining was used to confirm the osteogenic potential of stem cells. Mettl3 small interfering RNA and Mettl3 overexpression lentivirus were used to assess the role of METTL3 in osteogenic differentiation of ASCs and OP-ASCs. RESULTS: The osteogenic differentiation capacity and Mettl3 expression significantly decreased in OP-ASCs. Moreover, Mettl3 silencing down-regulated the osteogenic ability of ASCs, and overexpression of Mettl3 recovered the impaired osteogenic capacity in OP-ASCs in vitro. CONCLUSION: The Mettl3 expression levels and osteogenic potential of OP-ASCs decreased. However, overexpression of METTL3 rescued the osteogenic ability of OP-ASCs, providing a new target for treatment of osteoporotic bone defects.

Connexin43 reduces LPS-induced inflammation in hDPCs through TLR4-NF-κB pathway via hemichannels.

OBJECTIVES: Connexin43 (Cx43) is involved in the inflammation of many tissue types. Dental caries is infectious disease resulting from mineralized tissue dissolution by a specific bacterial population, causing pulp inflammation. However, Cx43's role in dental pulp remains unclear. Here, we investigated the function of Cx43 during pulp inflammation. MATERIALS AND METHODS: We constructed a dentin injury model in Sprague-Dawley rats to investigate changes in Cx43 expression during pulp inflammation. Cx43 was inhibited in human dental pulp cells (hDPCs) that had been stimulated with lipopolysaccharide (LPS) to investigate the effect of Cx43 on inflammatory response. Promotion of TLR4-NF-κB pathway activity and special Cx43 channel inhibitors were used to clarify the function of Cx43 in hDPCs. RESULTS: Dentin injury led to low-level inflammation in dental pulp. Following dentin injury, Cx43 expression initially decreased before gradually recovering to normal levels. Cx43 inhibition reduced LPS-induced expression of inflammatory cytokines and NF-κB pathway activity. Promotion of NF-κB pathway activity counteracted the effect of Cx43 in hDPCs. Furthermore, inhibition of Cx43 hemichannels reduced LPS-induced inflammatory cytokine expression. CONCLUSIONS: Cx43 is involved in inflammation of dental pulp, while its inhibition reduced LPS-induced inflammation in hDPCs through NF-κB pathway via blockage of hemichannels.

Broadening the biocompatibility of gold nanorods from rat to Macaca fascicularis: advancing clinical potential.

BACKGROUND: The biomedical field has used gold nanorods (GNRs) for decades; however, clinical trials and translation is limited except gold nanoshells. The preparation of gold nanoshells is more complex than that of polyethylene glycol-modified GNRs (PEG-GNRs), and it is difficult to ensure uniform thickness. It is important to encourage and broaden the use of the star member (PEG-GNRs) of gold nanoparticles family for clinical translation. Existing studies on PEG-GNRs are limited with no relevant systematic progression in non-human primates. Herein, we assessed the systematic biocompatibility of PEG-GNRs in rats and clinically relevant Macaca fascicularis. RESULTS: In this small animal study, we administrated multiple doses of PEG-GNRs to rats and observed good biocompatibility. In the non-human primate study, PEG-GNRs had a longer blood half-life and produced a negligible immune response. Histological analysis revealed no significant abnormality. CONCLUSIONS: PEG-GNRs were well-tolerated with good biocompatibility in both small animals and large non-human primates. The information gained from the comprehensive systemic toxicity assessment of PEG-GNRs in M. fascicularis will be helpful for translation to clinical trials.

[Osteogenic Capacity and Mettl14 and Notch1 Expression of Adipose-Derived Stem Cells from Osteoporotic Rats].

OBJECTIVE: To investigate the differences in the osteogenic capacity of osteoporotic adipose-derived stem cells (OP-ASCs) and normal control adipose-derived stem cells (Ctrl-ASCs), and to examine the expression levels of RNA methyltransferase like 14 (Mettl14) and the Notch signaling molecule 1 (Notch1). METHODS: The osteoporosis (OP) model of SD rats was established with ovariectomy (OVX). Micro-CT, HE staining and Masson staining were performed to identify the successful establishment of the OP model, OP-ASCs and Ctrl-ASCs were isolated and cultured adherently. Then, the three-way differentiation capacity of the adipose-derived stem cells (ASCs) was determined through alizarin red staining, alcian blue staining and oil red O staining and flow cytometry was conducted to examine the surface antigens CD29, CD44, CD90, CD31, CD34, and CD45. Alizarin red staining and comparison of the mRNA and protein expression of Run-related transcription factor 2 (Runx2) were done to explore the differences in osteogenic potential of OP-ASCs and Ctrl-ASCs. Real-time PCR and Western blot were performed to explore the expression differences of Mettl14 and Notch1 at mRNA and protein levels between OP-ASCs and Ctrl-ASCs. RESULTS: Micro-CT, HE and Masson staining results showed that the number of trabecular bone decreased and the spacing increased in the tibias of the osteoporosis group (OP group) compared with those of the control group (Ctrl group), indicating that the OP model was established successfully. Three-way differentiation and flow cytometry results confirmed the successful isolation and culture of ASCs. After osteogenic induction, alizarin red staining showed that OP-ASCs had fewer number and more scattered distribution of mineralized nodules than Ctrl-ASCs did. The expression of Runx2 in OP-ASCs was lower than that in Ctrl-ASCs ( P<0.05). Mettl14 as well as Notch1 showed lower expression in OP-ASCs than they did in Ctrl-ASCs ( P<0.05). CONCLUSION: The osteogenic capacity of OP-ASCs was lower compared with that of Ctrl-ASCs, Mettl14 expression of OP-ASCs was decreased compared with that of Ctrl-ASCs, and the Notch signaling pathway was inhibited in OP-ASCs. The study helps build the foundation for further investigation in the specific mechanisms of Mettl14 and Notch1 during osteogenic differentiation of OP-ASCs.

Modified Tragus Edge and Transmasseteric Anteroparotid Approach for Intracapsular and Condylar Neck Fractures.

The aim of this study was to evaluate the effects of protecting the facial nerve and reducing the scar visibility using a modified tragus edge and transmasseteric anteroparotid approach compared to classic preauricular approach for intracapsular and condylar neck fractures. This retrospective study included 64 patients (78 sides) who underwent surgical treatment for intracapsular or condylar neck fractures from January 2014 to June 2018. Patients were divided into the experimental group (treated via a modified tragus edge and transmasseteric anteroparotid approach), and the control group (treated via the classical preauricular approach). Therapeutic outcome assessment parameters included facial nerve injury, salivary fistulae, wound infection, restricted mouth opening, postoperative occlusion disorders, and scar visibility. In the control group, there were 3 cases of facial nerve injuries and 2 cases of salivary fistulae. One case of temporary facial nerve injury occurred in the experimental group, with complete recovery within 1 month. The scars were less visible in the experimental group than in the control group. These results suggest that a modified tragus edge and transmasseteric anteroparotid approach reduced the incidences of facial nerve injuries, minimized the scar visibility, improved exposure of the operative site and fixation of titanium screws or plates, and did not increase the frequency of other complications.

Functional Reconstruction of Mandibular Segment Defects With Individual Preformed Reconstruction Plate and Computed Tomographic Angiography-Aided Iliac Crest Flap.

PURPOSE: With the development of imaging technology and computer-assisted surgery in oral and maxillofacial surgery, digital technology is widely used in vascularized bone flap grafts for mandibular reconstruction. The aim of this study was to use digital technology throughout the treatment process to show that digital techniques can provide a reliable and accurate match between the mandible and the iliac crest flap to achieve functional reconstruction of mandibular segment defects. MATERIALS AND METHODS: Twenty patients underwent 3-dimensional (3D) computed tomography (CT), mirroring technology, 3D model prototyping, and CT angiography (CTA) for treatment planning. Individual preformed reconstruction plates were fabricated and iliac crest flaps were designed preoperatively. After complete resection of the mandibular lesion, the iliac crest flap was shaped to reconstruct the mandibular defects. RESULTS: During follow-up (range, 12 to 36 months), the facial shape, facial symmetry, and mouth opening of all patients recovered well. The 3D CT reconstruction also was evaluated for height, width, length, and bone healing of the iliac crest flap. Postoperative examination showed ideal bone union between the iliac crest flap and the mandible at 6 months. Nine patients received implant-supported fixed dentures to restore dentition. After follow-up, all patients were satisfied with their facial esthetics and function. The new mandible provided a suitable 3D position for implant-supported fixed partial dentures. CONCLUSION: Use of digital techniques throughout the course of treatment improves the predictability and convenience of functional mandibular reconstruction. Individual preformed reconstruction plates and CTA effectively guaranteed the accuracy of iliac flap preparation.

Wnt10b regulates osteogenesis of adipose-derived stem cells through Wnt/ß-catenin signalling pathway in osteoporosis.

Our previous finding revealed that the Wnt10b RNA expression of osteoporotic adipose-derived stem cells (OP-ASCs) with impaired osteogenic capacity was significantly reduced than that of ASCs. There are no ideas that the relationship between the OP-ASCs' impaired osteogenic potential and Wnt10b expression. This study aimed to indicate the potential molecular mechanisms and functional role of Wnt10b in OP-ASCs, as well as to investigate a potential application to reverse the OP-ASCs' impaired osteogenic differentiation potential. The OP-ASCs and ASCs were harvested from the inguinal fat of osteoporosis (OP) mice with bilateral ovariectomy (OVX) and normal mice. qPCR and WB were used to detect the different levels of the expression of the Wnt10b RNA in both OP-ASCs and ASCs. Lentiviral-mediated regulation of Wnt10b expression was employed for OP-ASCs, and the detection of the expression levels of key molecules in the Wnt signalling pathway and key osteogenic factors was performed through qPCR and WB in vitro experiments. The capacity of OP-ASCs to osteogenesis was determined using alizarin red staining. Lastly, the repair effect of the BCP scaffolds incorporating modified OP-ASCs on the critical-sized calvarial defects (CSCDs) in OP mice was scanned and detected by micro-computed tomography, haematoxylin and eosin staining, Masson's trichrome staining and immunohistochemistry. First, we discovered that both the RNA and protein expression levels of Wnt10b were significantly lower in OP-ASCs than that in ASCs. In vitro experiments, upregulation of Wnt10b could activate the Wnt signalling pathway, and increase expression of ß-catenin, Lef1, Runx2 and osteopontin (Opn), thereby enhancing the osteogenic ability of OP-ASCs. In addition, the OP-ASCs with Wnt10b-overexpressing could promote the repair of CSCD in osteoporotic mice with increasing new bone volume, bone mineral density, and increased expression of Opn in new bone in vivo. Taken together, overexpression of Wnt10b could partially facilitate the differentiation of OP-ASCs towards osteogenesis and accelerated the healing of bone defects by activating the Wnt/ß-catenin signalling pathway in vitro and in vivo experiments. This study confirmed the important role of Wnt10b in regulating the osteogenic differentiation capability of OP-ASCs and indicated Wnt10b could be a potential therapeutic target for reversing the impaired osteogenic capabilities of OP-ASCs to therapy bone defects of OP patients.

Biomimetic fabrication of sr-silk fibroin co-assembly hydroxyapatite based microspheres with angiogenic and osteogenic properties for bone tissue engineering.

Bone defects caused by trauma, tumor resection, or developmental abnormalities are important issues in clinical practice. The vigorous development of tissue engineering technology provides new ideas and directions for regenerating bone defects. Hydroxyapatite (HAp), a bioactive ceramic, is extensively used in bone tissue engineering because of its excellent osteoinductive performance. However, its application is challenged by its single function and conventional environment-unfriendly synthesis methods. In this study, we successfully "green" synthesized sr-silk fibroin co-assembly hydroxyapatite nanoparticles (Sr-SF-HA) using silk fibroin (SF) as a biomineralized template, thus enabling it to have angiogenic activity and achieving the combination of organic and inorganic substances. Then, the rough composite microspheres loaded with Sr-SF-HA (CS/Sr-SF-HA) through electrostatic spraying technology and freeze-drying method were prepared. The CCK-8 test and live/dead cell staining showed excellent biocompatibility of CS/Sr-SF-HA. Alkaline phosphatase (ALP) staining, alizarin red staining (ARS), immunofluorescence, western blotting, and qRT-PCR test showed that CS/Sr-SF-HA activated the expression of related genes and proteins, thus inducing the osteogenic differentiation of rBMSCs. Moreover, tube formation experiments, scratch experiments, immunofluorescence, and qRT-PCR detection indicated that CS/Sr-SF-HA have good angiogenic activity. Furthermore, in vivo studies showed that the CS/Sr-SF-HA possesses excellent biocompatibility, vascular activity, as well as ectopic osteogenic ability in the subcutaneous pocket of rats. This study indicates that the construction of CS/Sr-SF-HA with angiogenic and osteogenic properties has great potential for bone tissue engineering.

Adipogenic and osteogenic differentiation of Lin(-)CD271(+)Sca-1(+) adipose-derived stem cells.

Adipose-derived stem cells (ASCs) have been defined as cells that undergo sustained in vitro growth and have multilineage differentiation potential. However, the identity and purification of ASCs has proved elusive due to the lack of specific markers and poor understanding of their physiological roles. Here, we prospectively isolated and identified a restricted homogeneous subpopulation of ASCs (Lin(-)CD271(+)Sca-1(+)) from mouse adipose tissues on the basis of cell-surface markers. Individual ASCs generated colony-forming unit-fibroblast at a high frequency and could differentiate into adipocytes, osteoblasts, and chondrocytes in vitro. Expansion of ASCs in a large quantity was feasible in medium supplemented with fibroblast growth factor-2 and leukemia inhibitory factor, without loss of adipogenic and osteogenic differentiation capacity. Moreover, we found that the transplanted ASCs can differentiate into adipocytes in adipogenic microenvironment in vivo and osteoblasts in osteogenic microenvironment in vivo. Thus we proved that Lin, CD271, and Sca-1 could be used as the specific markers to purify ASCs from adipose tissue. The method we established to identify ASCs as defined in vivo entities will help develop ASCs transplantation as a new therapeutic strategy for bone regeneration and adipose tissue regeneration in clinic.

Reconstruction of orbital wall fractures with superior orbital fissure syndrome using individualized preformed titanium mesh: a pilot study.

OBJECTIVE: The aim was to preliminarily evaluate the effect of individualized preformed titanium mesh in the treatment of orbital wall fractures with superior orbital fissure syndrome (SOFS). STUDY DESIGN: This study consisted of 10 patients of orbital wall fracture and SOFS who were treated at the Affiliated Stomatology Hospital of Southwest Medical University. On the basis of preoperative computed tomography data, individualized titanium mesh was produced by mirror engineering and rapid prototyping, and it was implanted into defects in the orbital walls to restore the normal anatomy. Early orbital wall reconstruction was performed to improve the SOFS. Postoperatively, the ocular and facial appearance and eye function were evaluated. RESULTS: The orbital structure, volume, and size of the SOF were restored in the 10 patients using the individualized titanium mesh. The symptoms of SOFS completely disappeared in all patients with no severe postoperative complications. Significant recovery of ocular and facial appearance and eye function was reported. CONCLUSIONS: This pilot study demonstrated that individualized preformed titanium mesh can accurately restore the orbital walls and the structure and size of the SOF, and it is useful in the treatment of SOFS without intraorbital bone fragment displacement.

Advanced glycation end products inhibit the osteogenic differentiation potential of adipose-derived stem cells in mice through autophagy.

BACKGROUND: Diabetes mellitus (DM) microenvironment will accelerate the accumulation of Advanced glycation end products (AGEs), adipose-derived stem cells (ASCs) have poor osteogenesis in the DM microenvironment. Studies suggest autophagy plays a vital role in osteogenesis, but the mechanism of the altered osteogenic potential of ASCs has not been elucidated. Bone tissue engineering by ASCs is widely used in the treatment of bone defects with diabetic osteoporosis (DOP). Therefore, it is meaningful to explore the effect of AGEs on the osteogenic differentiation potential of ASCs and its potential mechanism for the repair of bone defects in DOP. MATERIALS AND METHODS: ASCs in C57BL/6 mice were isolated, cultured, then treated with AGEs, subsequently, cell viability and proliferation were detected through Cell Counting Kit 8 assay. 3-Methyladenine (3-MA), an autophagic inhibitor used to inhibit autophagic levels. Rapamycin (Rapa), an autophagy activator that further activated autophagy levels by inhibiting mTOR.The osteogenesis and autophagy changes of ASCs were analyzed by flow cytometry, qPCR, western blot, immunofluorescence, alkaline phosphatase (ALP) and alizarin red staining. RESULTS: AGEs reduced the autophagy level and osteogenic potential of ASCs. After 3-MA reduced autophagy, the osteogenic potential of ASCs also decreased. AGEs co-treatment with 3-MA, the levels of osteogenesis and autophagy reduced more significantly. When autophagy was activated by Rapa, it was found that it could rescue the reduced osteogenic potential of AGEs. CONCLUSIONS: AGEs reduce the osteogenic differentiation potential of ASCs through autophagy, and may provide a reference for the treatment of bone defects with diabetes osteoporosis.

Application of Nucleic Acid Nanomaterials in the Treatment of Endocrine and Metabolic Diseases.

Endocrine and metabolic diseases are the most prevalent chronic diseases globally, posing the greatest hazard to human health. Although various medications are applied in treating endocrine and metabolic illnesses, numerous obstacles exist to overcome. Nucleic acid nanomaterials are novel materials synthesized and engineered in the laboratory. In this case, Nucleic acids are employed as non-biological nanomaterials instead of serving as carriers of genetic information in live cells. Because of their high biocompatibility and editability, nucleic acid nanomaterials were frequently employed in disease diagnosis and therapy. In this review, recent developments and new viewpoints on nucleic acid nanomaterials are highlighted in the fields of diabetes mellitus and other endocrine and metabolic diseases.

Hydrogel Drug Delivery Systems for Bone Regeneration.

With the in-depth understanding of bone regeneration mechanisms and the development of bone tissue engineering, a variety of scaffold carrier materials with desirable physicochemical properties and biological functions have recently emerged in the field of bone regeneration. Hydrogels are being increasingly used in the field of bone regeneration and tissue engineering because of their biocompatibility, unique swelling properties, and relative ease of fabrication. Hydrogel drug delivery systems comprise cells, cytokines, an extracellular matrix, and small molecule nucleotides, which have different properties depending on their chemical or physical cross-linking. Additionally, hydrogels can be designed for different types of drug delivery for specific applications. In this paper, we summarize recent research in the field of bone regeneration using hydrogels as delivery carriers, detail the application of hydrogels in bone defect diseases and their mechanisms, and discuss future research directions of hydrogel drug delivery systems in bone tissue engineering.

Modified tragus edge incision and transmasseteric anteroparotid approach to condyle reconstruction.

OBJECTIVES: This study aimed to analyze the application value of a modified tragus edge incision and transmasseteric anteroparotid approach to condyle reconstruction. METHODS: Condyle reconstruction was performed in 16 patients (9 females and 7 males) with modified tragus edge incision and transmasseteric anteroparotid approach. After regular follow-up, the function of condyle reconstruction was evaluated by clinical indicators, such as parotid salivary fistula, facial nerve function, mouth opening, occlusal relationship, and facial scar. The morphology of rib graft rib cartilage was evaluated by imaging indicators, such as panoramic radiography, CT, and three-dimensional CT image reconstruction. RESULTS: At 6-36 months postoperative follow-up, all patients had good recovery of facial appearance, concealed incisional scar, no parotid salivary fistula, good mouth opening, and occlusion. One case had temporary facial paralysis and recovered after treatment. Radiographic evaluation further showed that costochondral graft survived in normal anatomic locations. CONCLUSIONS: The modified tragus edge incision and transmasseteric anteroparotid approach can effectively reduce parotid salivary fistula and facial nerve injury in condylar reconstruction. The surgical field was clearly exposed, and the incision scar was concealed without increasing the incidence of other complications. Thus, this approach is worthy of clinical promotion.

LncRNA-AK137033 inhibits the osteogenic potential of adipose-derived stem cells in diabetic osteoporosis by regulating Wnt signaling pathway via DNA methylation.

OBJECTIVES: Bone tissue engineering based on adipose-derived stem cells (ASCs) is expected to become a new treatment for diabetic osteoporosis (DOP) patients with bone defects. However, compared with control ASCs (CON-ASCs), osteogenic potential of DOP-ASCs is decreased, which increased the difficulty of bone reconstruction in DOP patients. Moreover, the cause of the poor osteogenesis of ASCs in a hyperglycemic microenvironment has not been elucidated. Therefore, this study explored the molecular mechanism of the decline in the osteogenic potential of DOP-ASCs from the perspective of epigenetics to provide a possible therapeutic target for bone repair in DOP patients with bone defects. MATERIALS AND METHODS: An animal model of DOP was established in mice. CON-ASCs and DOP-ASCs were isolated from CON and DOP mice, respectively. AK137033 small interfering RNA (SiRNA) and an AK137033 overexpression plasmid were used to regulate the expression of AK137033 in CON-ASCs and DOP-ASCs in vitro. Lentiviruses that carried shRNA-AK137033 or AK137033 cDNA were used to knockdown or overexpress AK137033, respectively, in CON-ASCs and DOP-ASCs in vivo. Hematoxylin and eosin (H&E), Masson's, alizarin red, and alkaline phosphatase (ALP) staining, micro-computed tomography (Micro-CT), flow cytometry, qPCR, western blotting, immunofluorescence, and bisulfite-specific PCR (BSP) were used to analyze the functional changes of ASCs. RESULTS: The DOP mouse model was established successfully. Compared with CON-ASCs, AK137033 expression, the DNA methylation level of the sFrp2 promoter region, Wnt signaling pathway markers, and the osteogenic differentiation potential were decreased in DOP-ASCs. In vitro experiments showed that AK137033 silencing inhibited the Wnt signaling pathway and osteogenic ability of CON-ASCs by reducing the DNA methylation level in the sFrp2 promoter region. Additionally, overexpression of AK137033 in DOP-ASCs rescued these changes caused by DOP. Moreover, the same results were obtained in vivo. CONCLUSIONS: LncRNA-AK137033 inhibits the osteogenic potential of DOP-ASCs by regulating the Wnt signaling pathway via modulating the DNA methylation level in the sFrp2 promoter region. This study provides an important reference to find new targets for the treatment of bone defects in DOP patients.

Downregulation of DNA methyltransferase-3a ameliorates the osteogenic differentiation ability of adipose-derived stem cells in diabetic osteoporosis via Wnt/ß-catenin signaling pathway.

BACKGROUND: Diabetes-related osteoporosis (DOP) is a chronic disease caused by the high glucose environment that induces a metabolic disorder of osteocytes and osteoblast-associated mesenchymal stem cells. The processes of bone defect repair and regeneration become extremely difficult with DOP. Adipose-derived stem cells (ASCs), as seed cells in bone tissue engineering technology, provide a promising therapeutic approach for bone regeneration in DOP patients. The osteogenic ability of ASCs is lower in a DOP model than that of control ASCs. DNA methylation, as a mechanism of epigenetic regulation, may be involved in DNA methylation of various genes, thereby participating in biological behaviors of various cells. Emerging evidence suggests that increased DNA methylation levels are associated with activation of Wnt/ß-catenin signaling pathway. The purpose of this study was to investigate the influence of the diabetic environment on the osteogenic potential of ASCs, to explore the role of DNA methylation on osteogenic differentiation of DOP-ASCs via Wnt/ß-catenin signaling pathway, and to improve the osteogenic differentiation ability of ASCs with DOP. METHODS: DOP-ASCs and control ASCs were isolated from DOP C57BL/6 and control mice, respectively. The multipotency of DOP-ASCs was confirmed by Alizarin Red-S, Oil Red-O, and Alcian blue staining. Real-time polymerase chain reaction (RT-PCR), immunofluorescence, and western blotting were used to analyze changes in markers of osteogenic differentiation, DNA methylation, and Wnt/ß-catenin signaling. Alizarin Red-S staining was also used to confirm changes in the osteogenic ability. DNMT small interfering RNA (siRNA), shRNA-Dnmt3a, and LVRNA-Dnmt3a were used to assess the role of Dnmt3a in osteogenic differentiation of control ASCs and DOP-ASCs. Micro-computed tomography, hematoxylin and eosin staining, and Masson staining were used to analyze changes in the osteogenic capability while downregulating Dnmt3a with lentivirus in DOP mice in vivo. RESULTS: The proliferative ability of DOP-ASCs was lower than that of control ASCs. DOP-ASCs showed a decrease in osteogenic differentiation capacity, lower Wnt/ß-catenin signaling pathway activity, and a higher level of Dnmt3a than control ASCs. When Dnmt3a was downregulated by siRNA and shRNA, osteogenic-related factors Runt-related transcription factor 2 and osteopontin, and activity of Wnt/ß-catenin signaling pathway were increased, which rescued the poor osteogenic potential of DOP-ASCs. When Dnmt3a was upregulated by LVRNA-Dnmt3a, the osteogenic ability was inhibited. The same results were obtained in vivo. CONCLUSIONS: Dnmt3a silencing rescues the negative effects of DOP on ASCs and provides a possible approach for bone tissue regeneration in patients with diabetic osteoporosis.

Biomimetic Design and Fabrication of Sericin-Hydroxyapatite Based Membranes With Osteogenic Activity for Periodontal Tissue Regeneration.

The guided tissue regeneration (GTR) technique is a promising treatment for periodontal tissue defects. GTR membranes build a mechanical barrier to control the ingrowth of the gingival epithelium and provide appropriate space for the regeneration of periodontal tissues, particularly alveolar bone. However, the existing GTR membranes only serve as barriers and lack the biological activity to induce alveolar bone regeneration. In this study, sericin-hydroxyapatite (Ser-HAP) composite nanomaterials were fabricated using a biomimetic mineralization method with sericin as an organic template. The mineralized Ser-HAP showed excellent biocompatibility and promoted the osteogenic differentiation of human periodontal membrane stem cells (hPDLSCs). Ser-HAP was combined with PVA using the freeze/thaw method to form PVA/Ser-HAP membranes. Further studies confirmed that PVA/Ser-HAP membranes do not affect the viability of hPDLSCs. Moreover, alkaline phosphatase (ALP) staining, alizarin red staining (ARS), and RT-qPCR detection revealed that PVA/Ser-HAP membranes induce the osteogenic differentiation of hPDLSCs by activating the expression of osteoblast-related genes, including ALP, Runx2, OCN, and OPN. The unique GTR membrane based on Ser-HAP induces the differentiation of hPDLSCs into osteoblasts without additional inducers, demonstrating the excellent potential for periodontal regeneration therapy.