Beagle Model Research Articles

Dental implants with electrochemical nanopattern formation to increase osseointegration

An electrochemical nanopattern formation (ENF) surface treatment was developed to overcome the limitations of conventional surface treatments. This study aimed to evaluate the cytocompatibility and preclinical efficacy of the newly developed ENF surfaces in comparison to conventional surfaces. The cytocompatibility of human mesenchymal stem cells, degree of bone formation, bone-to-implant contact (BIC) ratio, and implant stability quotient (ISQ) were investigated using rabbit and beagle models. Overall, the ENF surfaces showed greater cytocompatibility than other surfaces. The ISQs of implants in rabbit tibias showed that ENF surfaces provided greater stability than other surfaces. In contrast, the ISQs of implants in beagle mandibles were similar for ENF and sandblasted large-grit acid-etched (SLA) surfaces. In the rabbit model, the degree of bone formation and BIC ratio were significantly higher for ENF surfaces than for other surfaces. However, the removal torque (RT) during implant removal was significantly higher for SLA surfaces than ENF surfaces. Thus, it was confirmed that ENF-treated dental implants can replace conventional implants, but further research is required to improve the surface roughness to increase the RT.

Using of Single-Layer Porcine Small Intestinal Submucosa in Urethroplasty on a Beagle Model.

Purpose To evaluate the role of porcine small intestinal submucosa (SIS) in reducing fistula during urethroplasty and to observe its degradation process in beagle models. Methods 22 male beagles were divided into the SIS group and control group. All animals received surgical operation to establish the hypospadias model. Urethroplasty was followed. In the SIS group, the urethra was covered with a single-layer SIS material while no SIS material covered in the control group. At the 2nd, 4th, and 12th weeks after the operation, there were 3, 3, and 5 animals in each group, respectively, sacrificed for surgical site histological examinations. The inflammation reaction and collagen hyperplasia levels were assessed. The fistula was identified by retrograde cystourethrography at the 4th and 12th weeks after the operation. Results the incidence of urethral fistula was 25% (2/8) in the SIS group and 75% (6/8) in the control group. The inflammation reaction of SIS and control groups had no significant difference (U = 52.50, P = 0.58). The collagen fiber increased in both groups; however, the SIS group had a much more gentle increase compared to the control group (U = −0.00, P < 0.001). In the SIS group, the SIS material was roughly complete on the specimens 2 w after surgery but became loose and discontinuous 4 w after surgery and could not be found 12 w after surgery. Conclusion The material can decrease the incidence of urethral fistula in the animal models, when used as a coverage layer. The SIS degradation process started 2 w–4 w after the operation and finished before 12 w in the animal model.

Bone Regeneration with 3D-Printed Hybrid Bone Scaffolds in a Canine Radial Bone Defect Model.

The repair of large bone defects remains a significant challenge in clinical practice and requires bone grafts or substitute materials. In this study, we developed a unique hybrid bone scaffold comprising a three dimensional (3D)-printed metal plate for weight bearing and a biodegradable polymer tube serving as bone conduit. We assessed the long-term effect of the hybrid bone scaffold in repairing radial bone defects in a beagle model. Bone defects were created surgically on the radial bone of three beagle dogs and individually-tailored scaffolds were used for reconstruction with or without injection of autologous bone and decellularized extracellular matrix (dECM). The repaired tissue was evaluated by X-ray, micro-computed tomography, and histological observation 6months after surgery. The functional integrity of hybrid bone scaffold-mediated reconstructions was assessed by gait analysis. In vivo analysis showed that the hybrid bone scaffolds maintained the physical space and bone conductivity around the defect. New bone was formed adjacent to the scaffolds. Addition of autologous bone and dECM in the polymer tube improved healing by enhancing bone induction and osteoconduction. Furthermore, the beagles' gait appeared normal by 4months. The future of bone healing and regeneration is closely related to advances in tissue engineering. Bone production using autologous bone and dECM loaded on 3D-printed hybrid bone scaffolds can successfully induce osteogenesis and provide mechanical force for functional bone regeneration, even in large bone defects.

Low-intensity pulsed ultrasound promotes periodontal regeneration in a beagle model of furcation involvement.

Objective: To evaluate the regeneration potential of periodontitis tissue treated by low-intensity pulsed ultrasound (LIPUS) combined with the guided tissue regeneration (GTR) technique in a beagle model of furcation involvement (FI). Background: Achieving predictable regeneration remains a clinical challenge for periodontitis tissue due to the compromised regenerative potential caused by chronic inflammation stimulation. LIPUS, an FDA-approved therapy for long bone fracture and non-unions, has been demonstrated effective in the in vitro attenuation of inflammation-induced dysfunction of periodontal ligament stem cells (PDLSCs), the key cells contributing to periodontal regeneration. However, the in vivo effect of LIPUS on periodontitis tissue is rarely reported. Methods: A beagle model of FI was established, and the experimental teeth were randomly assigned into three groups: control group, GTR group, and GTR+LIPUS group. Radiographic examinations were performed, and clinical periodontal parameters were recorded to reflect the periodontal condition of different groups. Histological analyses using H&E and Masson’s staining were conducted to evaluate the periodontal tissue regeneration. Results: LIPUS could enhance new periodontal bone formation and bone matrix maturity in FI after GTR treatment. Moreover, clinical assessment and histomorphometric analyses revealed less inflammatory infiltration and superior vascularization within bone grafts in the LIPUS treatment group, indicating the anti-inflammatory and pro-angiogenic effects of LIPUS in FI. Conclusion: Our investigation on a large animal model demonstrated that LIPUS is a promising adjunctive approach for the regeneration of periodontitis tissue, paving a new avenue for LIPUS application in the field of periodontal regenerative medicine.

A breakthrough trial of an artificial liver without systemic heparinization in hyperbilirubinemia beagle models.

The development of wearable artificial livers was restricted to device miniaturization and bleeding risk with water-soluble anticoagulants. Herein, a double-deck column filled with solid anticoagulant microspheres and Kevlar porous microspheres (KPMs, bilirubin adsorbents) was connected with the principle machine of wearable artificial liver (approximately 9 kg) to treat hyperbilirubinemia beagles for the first time. With the initial normal dose of heparin, the double-deck column could afford 3 h hemoperfusion in whole blood without thrombus formation. The removal efficiency of the double-deck column for total bilirubin (TBIL) was 31.4%. Interestingly, the excessive amounts of hepatocyte metabolites were also decreased by approximately 25%. The “anticoagulant + column” realized safe and effective whole blood hemoperfusion without the plasma separation system and heparin pump; however, the proposed principle machine of wearable artificial liver and “anticoagulant + column” cannot completely replace the bio-liver now. The intelligence of the device and the versatility of the adsorbent need to be improved; moreover, advanced experimental techniques need to be developed to validate the survival rates in animals. Overall, this study is a meaningful trial for the development of wearable artificial livers in the future.

Apoptotic vesicles activate autophagy in recipient cells to induce angiogenesis and dental pulp regeneration

Extracellular vesicles (EVs) derived from living cells play important roles in donor cell-induced recipient tissue regeneration. Although numerous studies have found that cells undergo apoptosis after implantation in an ischemic-hypoxic environment, the roles played by the EVs released by apoptotic cells are largely unknown. In this study, we obtained apoptotic vesicles (apoVs) derived from human deciduous pulp stem cells and explored their effects on the dental pulp regeneration process. Our work showed that apoVs were ingested by endothelial cells (ECs) and elevated the expression of angiogenesis-related genes, leading to pulp revascularization and tissue regeneration. Furthermore, we found that, at the molecular level, apoV-carried mitochondrial Tu translation elongation factor was transported and regulated the angiogenic activation of ECs via the transcription factor EB-autophagy pathway. In a beagle model of dental pulp regeneration in situ, apoVs recruited endogenous ECs and facilitated the formation of dental-pulp-like tissue rich in blood vessels. These findings revealed the significance of apoptosis in tissue regeneration and demonstrated the potential of using apoVs to promote angiogenesis in clinical applications.

Anabolic effects of rhPTH and novel PTH analog on titanium osseointegration and bone regeneration in ovariectomized beagle model

Anabolic effects of rhPTH and novel PTH analog on titanium osseointegration and bone regeneration in ovariectomized beagle model

Gallnut Tannic Acid Exerts Anti-stress Effects on Stress-Induced Inflammatory Response, Dysbiotic Gut Microbiota, and Alterations of Serum Metabolic Profile in Beagle Dogs.

Stress exposure is a potential threat to humans who live or work in extreme environments, often leading to oxidative stress, inflammatory response, intestinal dysbiosis, and metabolic disorders. Gallnut tannic acid (TA), a naturally occurring polyphenolic compound, has become a compelling source due to its favorable anti-diarrheal, anti-oxidative, anti-inflammatory, and anti-microbial activities. Thus, this study aimed to evaluate the anti-stress effects of gallnut TA on the stress-induced inflammatory response, dysbiotic gut microbiota, and alterations of serum metabolic profile using beagle models. A total of 13 beagle dogs were randomly divided into the stress (ST) and ST + TA groups. Dietary supplementation with TA at 2.5 g/kg was individually fed to each dog in the ST + TA group for 14 consecutive days. On day 7, all dogs were transported for 3 h from a stressful environment (days 1–7) to a livable site (days 8–14). In our results, TA relieved environmental stress-induced diarrheal symptoms in dogs and were shown to protect from myocardial injury and help improve immunity by serum biochemistry and hematology analysis. Also, TA inhibited the secretion of serum hormones [cortisol (COR), glucocorticoid (GC), and adrenocorticotropic hormone (ACTH)] and the expression of heat shock protein (HSP) 70 to protect dogs from stress-induced injury, thereby relieving oxidative stress and inflammatory response. Fecal 16S rRNA gene sequencing revealed that TA stimulated the growth of beneficial bacteria (Allobaculum, Dubosiella, Coriobacteriaceae_UCG-002, and Faecalibaculum) and suppressed the growth of pathogenic bacteria (Escherichia-Shigella and Streptococcus), thereby increasing fecal butyrate levels. Serum metabolomics further showed that phytosphingosine, indoleacetic acid, arachidonic acid, and biotin, related to the metabolism of sphingolipid, tryptophan, arachidonic acid, and biotin, respectively, could serve as potential biomarkers of stress exposure. Furthermore, Spearman’s correlation analysis showed strong relationships between the four potential serum biomarkers and differential bacteria. Overall, gallnut TA may be a potential prebiotic for the prevention and treatment of stress-induced metabolic disorders by targeting intestinal microbiota.

ROS-NLRP3 signaling pathway induces sterile inflammation after thulium laser resection of the prostate.

The sterile inflammation (SI) of the urinary tract is a common problem requiring serious consideration after prostatectomy. This study mainly focuses on the role of the reactive oxygen species-NLR family, pyrin domain-containing 3 (ROS-NLRP3) signaling pathway in SI after thulium laser resection of the prostate (TmLRP). Urinary cytokines weredetermined in patients who received TmLRP, and heat shock protein 70 (HSP70) was detected in the resected tissues. The involvement of ROS signaling in HSP70-induced inflammation was explored in THP-1 cells with or without N-acetyl- l-cysteine (NAC) pretreatment. The function of NLRP3 and Caspase-1 was determined by Western blot analysis, enzyme-linked immunosorbent assay (ELISA), and polymerase chain reaction. These phenomena and mechanisms wereverified by the beagle modelsthat received TmLRP. Clinical urine samples after TmLRP showed high expression of inflammatory factors and peaked 3-5 days after surgery. The high expression of HSP70 in the resected tissues was observed. After HSP70 stimulation, the expression of ROS, NLRP3, Caspase-1, and interleukin-18 (IL-18) increased significantly and could be reduced by ROS inhibitor NAC. The expression of IL-1β and IL-18 could be inhibited by NLRP3 or Caspase-1 inhibitors. In beagle models that received TmLRP, HSP70, NLRP3, Caspase-1, IL-1β, and IL-18 were highly expressed in the wound tissue or urine, and could also be reduced by NAC pretreatment. Activation of the ROS-NLRP3 signaling pathway induces SI in the wound after prostatectomy. Inhibition of this pathway may be effective for clinical prevention and treatment of SI and related complications after prostatectomy.

Chemically Extracted Acellular Nerve Allograft Seeded with SDNF and Autogenic ADSCs for Peripheral Nerve Repairment in a Beagle Model

Peripheral nerve repair is a major challenge in clinical practice. Nerve grafting is required to treat severe peripheral nerve defects caused by injuries. Available nerve sources for autologous transplantation are limited. Stem cells offer promise for peripheral nerve repair and regeneration. However, the current lack of Schwann cell phenotype, high costs, and major trauma limit the production of Schwann cells from stem cell differentiation.

Polysilsesquioxane with potent resistance to intraoral stress: Functional coating material for the advanced dental materials

Since the oral cavity is a harsh environment where various germs and chemical and mechanical stress exist simultaneously, well-organized hybrid technology should be considered in the design of cutting-edge dental materials. Although the Clear Overlay Appliance (COA) is widely used as a transparent orthodontic device, it still requires specific modifications to overcome the poor durability and frequent contamination that cause the patient's therapeutic burden. Herein, robust polysilsesquioxane (PSQ) containing quaternary ammonium cations (QACs) and long alkyl chains (LACs) in a durable siloxane matrix are reported as coating materials for the advanced COAs. The PSQ coatings are engineered to have a ladder-like structure that exhibits excellent stability under various pH and enzymatic conditions. Experiments simulating the dynamic intraoral are established to investigate the effects of PSQ coatings for the functional improvement of COA. The QACs and LACs firmly fixed to the siloxane matrix cause bacterial contact killing to prevent the contamination of COAs in the environment exposed to bacteria. The ladder-like siloxane matrix of the coating protects the COAs from intraoral abrasion forces and shearing movements with its flexible adaptability to external stresses. This study clarifies the clinical application potential of the coated COAs via in-vivo experiments using the beagle model.

Tubularized urethral reconstruction using everted saphenous vein graft in a beagle model

BackgroundA long segment stricture in the anterior urethra is a challenge in urology. We conducted a study to investigate the efficacy of anterior urethral reconstruction using an everted saphenous vein graft (SVG) in a tubular fashion.MethodsTwelve male beagles were randomly divided into three groups: experimental group (n = 5), control group (n = 5) and normal group (n = 2). A 3 cm defect in the anterior urethra was created. Autologous SVG was harvested. In the experimental group, urethral defect was replaced by an everted SVG in a tubular fashion. In the control group, urethral reconstruction was performed using an uneverted SVG. Beagles in all groups received retrograde urethrography to evaluate urethral patency and were killed for histological examination 6 months after operation.ResultsFour beagles in the experimental group had no voiding difficulty and the other one could not void spontaneously. Retrograde urethrography showed the four beagles in experimental group had wide urethral lumens. Ether urethral stricture or fistula were detected in all animals in the control group. Histological analysis of the four beagles in the experimental group indicated the everted SVG completely integrated into the urethra. The reconstructed urethra contained a wide lumen and was completely covered by urothelium. The periurethral collagen and muscle fibers formed and were highly organized. Everted SVG showed a high ability of neovascularization. In the control group, the reconstructed segment showed a fibrotic urethral lumen where the urothelium was not intact. Only few new capillaries were formed.ConclusionsEverted SVG demonstrates for a promising strategy for potential urethral stricture repair.

Research on spatial motion safety constraints and cooperative control of robot-assisted craniotomy: Beagle model experiment verification.

Traditional craniotomy depends primarily on the experience of the surgeon. However, the accuracy of manual operation is limited and carries certain surgical risks. The interaction method of current robot-assisted craniotomy is unnatural and inadaptive to the operating style of the surgeon. In this research, we built a hands-on synergistic robotics craniotomy system with human-machine collaboration. Safe isometric surfaces and virtual restraint methods are combined to achieve highly accurate, efficient, minimally invasive and safe craniotomy. Fifteen three-dimensional (3D)-printed beagle skull models were used to evaluate the system accuracy and the related image guidance process. It mainly includes the design of the surgical plan, the adopted strategy based on motion constraint and safe isometric surface, and the impedance control method based on the position inner loop via the human-machine collaboration method. The trajectory tracking experiment was performed by applying human-machine collaboration, and completed an experiment on the 3D-printed beagle skull models involving drilling and milling of the skull performed by the robot, and evaluation of accuracy via computed tomographic (CT) scanning verification after the operation. The 3D-printed beagle skull model experiment shows that the average errors for the top surface and the bottom surface, and the angle error were 0.81±0.15mm, 0.89±0.12mm, and 1.74°±0.16°, respectively. The average milling position errors for the top and bottom surfaces were 0.87±0.19 and 0.93±0.22mm, respectively. The performance of the robot system was evaluated and verified using a 3D-printed beagle model experiment. The proposed collaborative surgical robot system is feasible and can complete a craniotomy, with improved accuracy and surgical safety.

Myocardial extracellular volume fraction analysis in doxorubicin-induced beagle models: comparison of dual-energy CT with equilibrium contrast-enhanced single-energy CT.

Dual-energy CT (DECT) permits the simultaneous operation of two different kV levels, providing a potential method toward the assessment of diffuse myocardial fibrosis. The purpose of this study was to determine the accuracy of DECT for evaluation of the myocardial extracellular volume (ECV) fraction in comparison with single-energy CT (SECT). Myocardial ECV was quantified in fifteen dogs using DECT and dynamic equilibrium SECT before and after doxorubicin administration. Cardiac magnetic resonance imaging (CMRI) was used to assess myocardial function. The histological collagen volume fraction (CVF) was calculated as the gold standard. The Bland-Altman analysis was performed to compare the agreement between DECT-ECV and SECT-ECV. The association among ECV values derived from DECT and SECT, CVF, and left ventricular ejection fraction (LVEF) were determined by correlation analysis. The variations of these values were evaluated using repeated ANOVA. The DECT- and SECT-ECV were increased with the elongation of modeling time (pre-modeling vs. 16-week models vs. 24-week models: DECT-ECV 24.1%±1.1%, 35.1%±1.3% and 37.6%±1.4%; SECT-ECV 22.9%±0.8%, 33.6%±1.2% and 36.3%±1.0%; n=30 in per-subject analysis, all P<0.05). Both ECV values of DECT and SECT correlated well with the histological CVF results (R=0.935 and 0.952 for the DECT-ECV and SECT-ECV; all P<0.001; n=13). Bland-Altman plots showed no significant differences between DECT- and SECT-ECV. DECT-ECV correlated well with both SECT-ECV and histology, showing the feasibility of DECT in evaluating doxorubicin-induced diffuse myocardial interstitial fibrosis.

Myocardial extracellular volume fraction quantification in an animal model of the doxorubicin-induced myocardial fibrosis: a synthetic hematocrit method using 3T cardiac magnetic resonance.

Visualization of diffuse myocardial fibrosis is challenging and mainly relies on histology. Cardiac magnetic resonance (CMR), which uses extracellular contrast agents, is a rapidly developing technique for measuring the extracellular volume (ECV). The objective of this study was to evaluate the feasibility of the synthetic myocardial ECV fraction based on 3.0 T CMR compared with the conventional ECV fraction. This study was approved by the local animal care and ethics committee. Fifteen beagle models with diffuse myocardial fibrosis, including 12 experimental and three control subjects, were generated by injecting doxorubicin 30 mg/m2 intravenously every three weeks for 24 weeks. Short-axis (SAX) and 4-chamber long-axis (LAX) T1 maps were acquired for both groups. The association between hematocrit (Hct) and native T1blood was derived from 9 non-contrast CMR T1 maps of 3 control beagles using regression analysis. Synthetic ECV was then calculated using the synthetic Hct and compared with conventional ECV at baseline and the 16th and 24th week after doxorubicin administration. The collagen volume fraction (CVF) value was measured on digital biopsy samples. Bland-Altman plots were used to analyze the agreement between conventional and synthetic ECV. Correlation analyses were performed to explore the association among conventional ECV, synthetic ECV, CVF, and left ventricular ejection fraction (LVEF). The regression model synthetic Hct = 816.46*R1blood - 0.01 (R2=0.617; P=0.012) was used to predict the Hct from native T1blood values. The conventional and synthetic ECV fractions of experimental animals at the 16th and 24th week after modeling were significantly higher than those measured at the baseline (31.4%±2.2% and 36.3%±2.1% vs. 22.9%±1.7%; 29.9%±2.4% and 36.1%±2.6% vs. 22.0%±2.4%; all with P<0.05). Bland-Altman plots showed a bias (1.0%) between conventional and synthetic ECV with 95% limits of agreement of -2.5% to 4.4% in the per-subject analysis (n=21) and a bias (1.0%) between conventional and synthetic ECV with 95% limits of agreement of -2.4% to 4.3% in the per-segment analysis (n=294). Conventional and synthetic ECV were well correlated with CVF (r=0.937 and 0.925, all with P<0.001, n=10). Our study showed promising results for using synthetic ECV compared with the conventional ECV for providing accurate quantification of myocardial ECV without the need for blood sampling.

Minimal Tissue Reaction after Chronic Subdural Electrode Implantation for Fully Implantable Brain-Machine Interfaces.

There is a growing interest in the use of electrocorticographic (ECoG) signals in brain–machine interfaces (BMIs). However, there is still a lack of studies involving the long-term evaluation of the tissue response related to electrode implantation. Here, we investigated biocompatibility, including chronic tissue response to subdural electrodes and a fully implantable wireless BMI device. We implanted a half-sized fully implantable device with subdural electrodes in six beagles for 6 months. Histological analysis of the surrounding tissues, including the dural membrane and cortices, was performed to evaluate the effects of chronic implantation. Our results showed no adverse events, including infectious signs, throughout the 6-month implantation period. Thick connective tissue proliferation was found in the surrounding tissues in the epidural space and subcutaneous space. Quantitative measures of subdural reactive tissues showed minimal encapsulation between the electrodes and the underlying cortex. Immunohistochemical evaluation showed no significant difference in the cell densities of neurons, astrocytes, and microglia between the implanted sites and contralateral sites. In conclusion, we established a beagle model to evaluate cortical implantable devices. We confirmed that a fully implantable wireless device and subdural electrodes could be stably maintained with sufficient biocompatibility in vivo.

Monitoring of anthracycline-induced myocardial injury using serial cardiac magnetic resonance: An animal study

PurposeTo assess the feasibility of using comprehensive serial cardiovascular MR (CMR) to evaluate bilateral ventricle mechanical changes and myocardial tissue characteristics, as well as correlations between the serial CMR and histology in a beagle model of anthracycline-induced cardiotoxicity. MethodsThis animal study was approved by the institutional review board. Serial CMR imaging was performed in a total of fifteen beagles at baseline (n = 15), at week 16 (n = 10) and week 24 (n = 7) post-anthracycline. Feature-tracking CMR (FT-CMR) was applied to measure bilateral ventricular (left ventricle (LV) and right ventricle (RV)) global peak strain including radial (GRS), circumferential (GCS) and longitudinal (GLS) strain. The changes in strain, LV/RV functional parameters, native T1, extracellular volume fraction (ECV) and collagen volume fraction (CVF) were calculated. ResultsCompared to baseline at weeks 16 and 24, significantly decreases to LV-GLS and native T1 were observed, while ECV significantly increased (all P < 0.05). LVEF significantly decreased and LV-EDV/ESV significantly increased at week 16 compared to baseline (all P < 0.05), but no further progression was seen at week 24. RV-GLS significantly decreased at week 16, but no further progression was seen at week 24, while RVEF was different until week 24. CVF increased significantly during modeling. Native T1 and ECV showed positive correlation with CVF (r = 0.645, P < 0.001), while LV-GLS showed negative correlation with CVF (r = −0.736, P < 0.05). ConclusionCardiotoxicity affects the RV slightly and less progressively than the LV. FT-CMR-based GLS, native T1 and ECV may potentially be used as imaging biomarkers for early monitoring of anthracycline-induced myocardial Injury.

A new technique for ureteral reconstruction using lingual mucosa grafts in a beagle model

To investigate the feasibility of ureteral reconstruction using lingual mucosa graft (LMG) and evaluate the histological changes of the engrafted LMG in beagles. Twelve male beagle dogs were randomly divided into groups A, B and C (n = 4). A ventral ureteral defect was created by excising half of the ureteral wall. The length of the defect was 3cm, 6cm, and 10cm in groups A, B, and C, respectively. The LMGs were harvested and employed to repair the ureteral defects in onlay fashion. Two dogs per group were sacrificed after 6months, with additional two dogs per group sacrificed after 12months. Intravenous urography (IVU) and macroscopic examination were performed to evaluate renal function and ureteral patency. Histological changes in the engrafted LMGs during the tissue incorporation process were assessed by histological analysis. There were no postoperative complications. Only one dog in group C developed a mild stricture near the proximal anastomosis. In the remaining 11 animals, IVU showed normal renal function and a wide ureteral caliber without stricture or fistula. The diameter of the LMG-reconstructed ureter was greater than that of the proximal and distal ureter (each p value < 0.01). The LMGs survived in situ with newly formed capillaries. The epithelium of the lingual mucosa resembled the urothelium in postoperative 12months. This new technique for ureteral reconstruction using LMGs is feasible. This approach is a promising alternative clinical treatment for curing long ureteral strictures.

Treated dentin matrix‐based scaffolds carrying TGF-β1/BMP4 for functional bio-root regeneration

Biomaterial scaffold-based bioengineered tooth root (bio-root) has been proven to be a prospective tool for the treatment of tooth loss. However, while emulating the mechanical integrity of native tooth root, the regenerated bio-root still has limited capacity to achieve long-term functional stability because of lacking the effective cervical seal. Enlightened by physiological cues from cervical seal development and recovery of native tooth, this study reports a bioinspired approach as incorporation of two pivotal odontogenic growth factors (TGF-β1 and BMP4) into biomaterial scaffold (treated dentin matrix, TDM) embodying a spatial interface gradient for functional enthesis formation to promote functional bio-root regeneration. The biological characteristics of dental follicle stem cells (DFSCs) induced by TGF-β1/BMP4 were studied by relevant gene and protein expressions in vitro as well as ectopic subcutaneous transplantation and orthotopic jaw bone implantation in vivo. We further fabricated artificial crown-TDM/TGF-β1/BMP4/DFSCs in beagle to verify the potential occlusional function of regenerated bio-root. Notably, TGF-β1/BMP4 synergistically activated proliferation, migration and osteoinductivity related to the enthesis differentiation of DFSCs as increasing expressions of Periostin, BSP, OPN, ALP, Vinculin, and Paxillin and ascending numbers of migrated cells. The TDM/TGF-β1/BMP4/DFSCs composites imparted the uniform and persistent inductive interface for neovascularization and canonical enthesis regeneration. During more than 5 months follow-up in beagle model, the effectively functional bio-roots were distinguished by outstanding biomechanical properties and healthy gingiva similar to native teeth. This notion of integrating TGF-β1/BMP4 with TDM and DFSCs provides an alternative strategy for biomimetic bio-root regeneration and other interface tissue engineering.

Decellularized nerve matrix hydrogel and glial-derived neurotrophic factor modifications assisted nerve repair with decellularized nerve matrix scaffolds.

Nerve defects are challenging to address clinically without satisfactory treatments. As a reliable alternative to autografts, decellularized nerve matrix scaffolds (DNM-S) have been widely used in clinics for surgical nerve repair. However, DNM-S remain inferior to autografts in their ability to support nerve regeneration for long nerve defects. In this study, we systematically and clearly presented the nano-architecture of nerve-specific structures, including the endoneurium, basement membrane and perineurium/epineurium in DNM-S. Furthermore, we modified the DNM-S by supplementing decellularized nerve matrix hydrogel (DNMG) and glial-derived neurotrophic factor (GDNF) and then bridged a 50-mm sciatic nerve defect in a beagle model. Fifteen beagles were randomly divided into three groups (five per group): an autograft group, DNM-S group and GDNF-DNMG-modified DNM-S (DNM-S/GDNF@DNMG) group. DNM-S/GDNF@DNMG, as optimized nerve grafts, were used to bridge nerve defects in the same manner as in the DNM-S group. The repair outcome was evaluated by behavioural observations, electrophysiological assessments, regenerated nerve tissue histology and reinnervated target muscle examinations. Compared with the DNM-S group, limb function, electrophysiological responses and histological findings were improved in the DNM-S/GDNF@DNMG group 6 months after grafting, reflecting a narrower gap between the effects of DNM-S and autografts. In conclusion, modification of DNM-S with DNMG and GDNF enhanced nerve regeneration and functional recovery, indicating that noncellular modification of DNM-S is a promising method for treating long nerve defects.