Tissue Healing Research Articles

Collagen patches releasing phosphatidylserine liposomes guide M1-to-M2 macrophage polarization and accelerate simultaneous bone and muscle healing

Bilateral communication between bones and muscles is essential for healing composite bone–muscle injuries from orthopedic surgeries and trauma. However, these injuries are often characterized by exaggerated inflammation, which can disrupt bone–muscle crosstalk, thereby seriously delaying the healing of either tissue. Existing approaches are largely effective at healing single tissues. However, simultaneous healing of multiple tissues remains challenging, with little research conducted to date. Here we introduce collagen patches that overcome this overlooked issue by harnessing the plasticity of macrophage phenotypes. Phosphatidylserine liposomes (PSLs) capable of shifting the macrophage phenotype from inflammatory M1 into anti-inflammatory/prohealing M2 were coated on collagen patches via a layer-by-layer method. Original collagen patches failed to improve tissue healing under inflammatory conditions coordinated by M1 macrophages. In contrast, PSL-coated collagen patches succeeded in accelerating bone and muscle healing by inducing a microenvironment dominated by M2 macrophages. In cell experiments, differentiation of preosteoblasts and myoblasts was completely inhibited by secretions of M1 macrophages but unaffected by those of M2 macrophages. RNA-seq analysis revealed that type I interferon and interleukin-6 signaling pathways were commonly upregulated in preosteoblasts and myoblasts upon stimulation with M1 macrophage secretions, thereby compromising their differentiation. This study demonstrates the benefit of PSL-mediated M1-to-M2 macrophage polarization for simultaneous bone and muscle healing, offering a potential strategy toward simultaneous regeneration of multiple tissues. Statement of significanceExisting approaches for tissue regeneration, which primarily utilize growth factors, have been largely effective at healing single tissues. However, simultaneous healing of multiple tissues remains challenging and has been little studied. Here we demonstrate that collagen patches releasing phosphatidylserine liposomes (PSLs) promote M1-to-M2 macrophage polarization and are effective for simultaneous healing of bone and muscle. Transcriptome analysis using next-generation sequencing reveals that differentiation of preosteoblasts and myoblasts is inhibited by the secretions of M1 macrophages but promoted by those of M2 macrophages, highlighting the importance of timely regulation of M1-to-M2 polarization in tissue regeneration. These findings provide new insight to tissue healing of multiple tissues.

Chemical, Antibacterial, and Cytotoxic Properties of Four Different Endodontic Sealer Leachates Over Time

IntroductionThe management of apical periodontitis involves the elimination of bacteria to achieve healing of the periapical tissues. To this end, understanding of the antimicrobial properties and cytotoxicity of root canal sealers over time is important. This study aimed to assess the cytocompatibility and antibacterial activity of leachates obtained from selected endodontic sealers. MethodsFour sealers were used in this study; AH Plus, an epoxy resin-based sealer, and three hydraulic calcium silicate-based sealers: AH Plus Bioceramic, BioRoot RCS, and BioRoot Flow. Sealer chemistry was assessed by scanning electron microscopy and energy dispersive spectrum analysis. Leachates of the tested sealers were prepared by immersing sealer discs in Hank’s balanced salt solution for 28 and 90 days. Element release was assessed using inductively coupled plasma mass spectroscopy. Enterococcus faecalis and Fusobacterium nucleatum were exposed to the leachates followed by colony-forming unit determination, and the human osteoblast-like cell line Saos-2 was assessed with regard to cell death, caspase expression and activity of alkaline phosphatase (ALP) after stimulation with the leachates. ResultsCalcium leaching was detected in the tricalcium silicate-based sealers, which increased the leachate pH significantly (P < .0001). AH Plus Bioceramic leachate displayed antimicrobial activity at 28 days against E. faecalis (P < .01). ALP levels were reduced in response to AH Plus Bioceramic and BioRoot RCS 1-day leachates (P < .05). High cell viability was observed after exposure to all sealers. ConclusionsThe leachates of the tested sealers were cytocompatible; however, their antimicrobial activity as well as their potential to induce the bone formation marker ALP was minimal.

A bitter flavonoid gum from Dorema aucheri accelerate wound healing in rats: Involvement of Bax/HSP 70 and hydroxyprolin mechanisms.

Dorema aucherigum (DAG) is a bitter flavonoid gum widely used for numerous medicinal purposes including wound recovery. The present work investigates the acute toxicity and wound-healing effects of DAG in excisional skin injury in rats. Sprague Dawley rats (24) were clustered into four groups, each rat had a full-thickness excisional dorsal neck injury (2.00cm) and addressed with 0.2mL of the following treatments for 15 days: Group A (vehicle), rats addressed with normal saline; Group B, rats received intrasite gel; C and D, rats addressed with 250 and 500mg/kg of DAG, respectively. The results revealed the absence of any toxic signs in rats who received oral dosages of 2 and 5g/kg of DAG. Wound healing was significantly accelerated following DAG treatments indicated by smaller open areas and higher wound contraction percentages compared to vehicle rats. Histological evaluation revealed higher fibroblast formation, collagen deposition, and noticeably lower inflammatory cell infiltration in granulated skin tissues of DAG-addressed rats compared to vehicle rats. DAG treatment caused significant modulation of immunohistochemical proteins (decreased Bax and increased HSP 70) and inflammatory mediators (reduced TNF-α, IL-6, and magnified IL-10), which were significantly varied compared to vehicle rats. Moreover, topical DAG treatment led to significant upregulation of the hydroxyproline (HDX) (collagen) and antioxidant content. At the same time, decreased the lipid peroxidation (MDA) levels in healed tissues obtained from DAG-treated rats. The present wound contraction by DAG might be linked with the modulatory effect of its phytochemicals (polysaccharides, flavonoids, and phenolic) on the cellular mechanisms, which justify their folkloric use and provokes further investigation as therapeutic drug additives for wound contraction.

FIBRIN-RICH PLASMA (PRF) EFFECT OF PLATELET COUNT ON BONE TISSUE REGENERATION

The use of autologous platelet concentrates, mainly Fibrin-Rich Plasma (PRF), has been increasingly used in dentistry as a bioactive material that presents itself as a treatment alternative for various clinical situations, such as example, periodontal defects, furcation lesions, osteonecrosis of the jaw, oral communication, maxillary sinus lifting, implant surgeries, regenerative surgeries of both soft and hard tissues and, in addition, it contributes positively to better tissue healing. Therefore, the present work consists of a systematic review of the literature seeking to analyze the evidence and effectiveness of the use of PRF in regenerative treatments. The research was carried out using the online database: PUBMED, choosing publications made in the last 5 years (2019-2024). A total of 697 articles were found, however, after applying the inclusion criteria, bias analysis and selection, 10 articles were selected. The results found in the present work allow us to affirm that the use of PRF in bone regeneration has positive and satisfactory effects.

Smart glucose-responsive hydrogel with ROS scavenging and homeostasis regulating properties for diabetic bone regeneration

Diabetic patients often suffer from delayed tissue healing and bone metabolism disorder, presenting a significant clinical challenge in the regeneration of diabetic bone defects. Hyperglycemia weakens osteogenesis and angiogenesis and destroys the balance of homeostasis. To solve this problem, a smart glucose-sensitivity sustained-release Resveratrol-loaded hydrogel platform is proposed to restore the function of mesenchymal stem cells. In this study, phenylboronic acid (PBA), known for its unique glucose sensitivity, is grafted onto the methacrylated gelatin (GelMA) chain, enabling the immobilization of Resveratrol (Res) molecules within the hybrid hydrogel through dynamic borate bond formation. Both in vivo and in vitro findings demonstrate that this hydrogel platform effectively scavenges excessive reactive oxygen species, ameliorates inflammation, modulates macrophage polarization, and enhances osteogenesis by activating the PI3K/AKT/GSK-3β signaling pathway. Collectively, all results suggest that this novel glucose-responsive hydrogel platform may be a potential therapy for diabetic bone regeneration.

The role of vitamin D in shoulder health: a comprehensive review of its impact on rotator cuff tears and surgical results.

Vitamin D deficiency is highly prevalent in the general population and is associated with various chronic health conditions. In addition to its role in bone mineralization, Vitamin D has various physiological effects that may impact the pathogenesis of shoulder pathologies. Vitamin D deficiency may also affect outcomes after shoulder surgeries, such as rotator cuff repair and total shoulder arthroplasty. Vitamin D plays a role in tissue healing, bone growth, and maintenance of homeostasis in skeletal muscle cells. Vitamin D also has anti-inflammatory effects that are important to rotator cuff health. Vitamin D deficiency is highly prevalent in patients with rotator cuff tears, suggesting its role as a potential risk factor. Vitamin D deficiency has been associated with decreased preoperative shoulder strength as well as increased re-tear rates, postoperative stiffness, and the need for revision surgery in patients who underwent rotator cuff repair. Studies have also demonstrated a potential association between vitamin D deficiency and increased risk of revision after total shoulder arthroplasty. Further research is necessary to elucidate the direct role of vitamin D in the pathogenesis of rotator cuff tears and its impact on clinical outcomes after rotator cuff surgery and total shoulder arthroplasty.

Hypertonic Dextrose Prolotherapy for Knee Osteoarthritis: A Comprehensive Review of Mechanism, Techniques, Limitations, and Side Effects.

This review delves into the potential of hypertonic dextrose prolotherapy (HDP) as a treatment for knee osteoarthritis (KOA), a prevalent condition, that significantly impacts individuals' quality of life, particularly affecting older adults. HDP involves injecting a hypertonic dextrose solution into or around the affected joint, inducing inflammation and subsequent tissue healing. This review examines various aspects of HDP, including its mechanism of action, comparative effectiveness with other therapies, dosage, and safety considerations as well as HDP's cost-effectiveness, safety profile, and efficacy in providing pain relief and improving function. Comparative studies indicate its superior effectiveness compared to other therapies such as saline, exercise, and steroids, with persistent benefits observed over extended follow-up periods. However, careful consideration of contraindications and potential side effects is crucial. Further research is warranted to conclusively establish its safety and long-term efficacy. In summary, HDP offers a promising avenue for managing KOA, potentially improving outcomes and enhancing the quality of life for affected individuals.

Odontogenic Maxillary Sinusitis: A clinical case report

underdiagnosed due to its nonspecific clinical presentation, which overlaps with other types of rhinosinusitis. The etiopathogenesis involves a complex interplay of factors including iatrogenic causes, periodontal infections, and traumatic events, leading to a persistent inflammatory response in the maxillary sinus. This report details a clinical case involving a 19-year-old male patient presenting with exacerbated sinusitis symptoms linked to a carious upper right first molar. Clinical manifestations included blurred vision, facial pain, and nasal regurgitation of liquids. Radiographic analysis revealed a radiolucent area indicative of sinus involvement, confirming the diagnosis of OMS.Surgical intervention comprised the extraction of the infected molar and the debridement of the maxillary sinus, followed by the application of Bichat’s fat pad to repair the resulting oroantral communication. This technique demonstrated effective closure of the defect, promoting tissue healing and reducing postoperative complications. The postoperative regimen included antibiotics, anti-inflammatories, and antihistamines, which facilitated recovery. This case underscores the necessity of a multidisciplinary approach in the diagnosis and management of OMS, integrating dental and surgical expertise to optimize patient outcomes. Imaging plays a crucial role in the diagnostic process, enabling precise identification of odontogenic lesions and their extent. The successful use of Bichat’s fat pad highlights its utility in oral-maxillofacial surgery for managing oroantral fistulas. This report contributes to the growing body of evidence supporting the importance of tailored surgical and medical strategies in managing complex cases of odontogenic maxillary sinusitis.

Platelet-Rich Therapies in Hernia Repair: A Comprehensive Review of the Impact of Platelet Concentrates on Mesh Integration in Hernia Management.

Mesh-augmented hernia repair is the gold standard in abdominal wall and hiatal/diaphragmatic hernia management and ranks among the most common procedures performed by general surgeons. However, it is associated with a series of drawbacks, including recurrence, mesh infection, and adhesion formation. To address these weaknesses, numerous biomaterials have been investigated for mesh coating. Platelet-rich plasma (PRP) is an autologous agent that promotes tissue healing through numerous cytokines and growth factors. In addition, many reports highlight its contribution to better integration of different types of coated meshes, compared to conventional uncoated meshes. The use of PRP-coated meshes for hernia repair has been reported in the literature, but a review of technical aspects and outcomes is missing. The aim of this comprehensive review is to report the experimental studies investigating the synergistic use of PRP and mesh implants in hernia animal models. A comprehensive literature search was conducted across PubMed/Medline, Web of Science, and Scopus without chronological constraints. In total, fourteen experimental and three clinical studies have been included. Among experimental trials, synthetic, biologic, and composite meshes were used in four, nine, and one study, respectively. In synthetic meshes, PRP-coating leads to increased antioxidant levels and collaged deposition, reduced oxidative stress, and improved inflammatory response, while studies on biological meshes revealed increased neovascularization and tissue integration, reduced inflammation, adhesion severity, and mechanical failure rates. Finally, PRP-coating of composite meshes results in reduced adhesions and improved mechanical strength. Despite the abundance of preclinical data, there is a scarcity of clinical studies, mainly due to the absence of an established protocol regarding PRP preparation and application. To this point in time, PRP has been used as a coating agent for the repair of abdominal and diaphragmatic hernias, as well as for mesh fixation. Clinical application of conclusions drawn from experimental studies may lead to improved results in hernia repair.

Rheological and osteogenic effect of Agaricus blazei Murill polysaccharides on composite hydrogels based on HPMC/graphene oxide – A preliminary study

This study aimed to prepare and preliminarily characterize the potential bone restorative effect of composite hydrogels based on hydroxypropylmethylcellulose (HPMC), graphene oxide (GO), and polysaccharides from Agaricus blazei Murill mushroom (PAb). The chemical composition and morphology of the biomaterials were analyzed using FTIR, XRD, SEM, and EDS. Rheological tests were conducted on the hydrogels to assess their flow properties for in vivo application and product stability. Cytotoxicity assays were performed using the GO (1 – 100 µg mL–1) against human neutrophils. Additionally, an in vivo tooth extraction test was carried out by applying HPMC hydrogels containing GO and PAb directly into the alveoli to enhance oral bone restoration. The rheological behavior of the hydrogels followed the Ostwald de Waele model (R² > 0.99), with flow index (n) values below 1.0, indicating a pseudoplastic behavior. Furthermore, the consistency index (k) values increased with the addition of GO and PAb, suggesting a more complex structure, and altered flow behavior at lower shear rates. In the MTT assay, GO exhibited low cytotoxicity towards human neutrophils, maintaining cell viability above 95.0 % even at high concentrations. For the in vivo study, a bisphosphonate-induced osteonecrosis model was used to assess bone tissue healing through macroscopic and radiographic analyses. A significant improvement was observed in the reduction of bone tissue loss in rats treated with the hydrogels compared to the negative control (ZA group). These findings indicate that composite hydrogels containing HMPC/GO/PAb have the potential to be used as biomaterials for mitigating bone loss.

Maxillary labial frenectomy: a randomized, controlled comparative study of two blue (445 nm) and infrared (980 nm) diode lasers versus surgical scalpel

BackgroundThis study aimed to compare the intra and postoperative complications of frenectomy procedure with a surgical scalpel versus 445 nm and 980 nm diode lasers.MethodsThis randomized controlled clinical trial was conducted on 174 patients requiring maxillary labial frenectomy. After completion of fixed orthodontic treatment and primary closure of maxillary diastema, the patients were randomly assigned into three groups (n = 58): group 1 (frenectomy via 445 nm diode laser, continuous-wave, 1.5 W), group 2 (frenectomy via 980 nm laser, continuous-wave, 1.7 W), and control group (V-Y plasty technique via scalpel). Intra-operative bleeding, discomfort in chewing and speaking, pain, and tissue healing were compared among the groups immediately, at 7 and 30 days postoperatively using the Kruskal-Wallis, Mann-Whitney, and Chi-square tests.ResultsPain scores were significantly lower in group 1 compared to group 2 (immediately and day 7, P < 0.05). Significant faster tissue healing at days 7 and 30 were observed in group 1 compared to group 2 (P < 0.05). Group 1 was superior to the control group regarding lower intraoperative bleeding, discomfort in chewing and speaking (immediately and day 7), lower pain (immediately and day 7), and tissue healing (day 7) (P < 0.05 for all). Group 2 was significantly superior to the control group in lower intraoperative bleeding, discomfort in chewing and speaking (immediately and day 7), and better tissue healing (day 7) (P < 0.05 for all).ConclusionsIn conclusion, diode laser frenectomy resulted in significantly lower intra and postoperative complications compared to the scalpel. Moreover, 445 nm diode laser showed significantly superior effects compared to 980 nm diode laser.Trial registrationThe study protocol was registered on 29.10.2022 at the Iranian Registry of Clinical Trials (www.irct.ir) (registration number: IRCT20220630055326N1).

Endothelial progenitor cells for fabrication of engineered vascular units and angiogenesis induction.

The promotion of vascularization and angiogenesis in the grafts is a crucial phenomenon in the healing process and tissue engineering. It has been shown that stem cells, especially endothelial progenitor cells (EPCs), can stimulate blood vessel formation inside the engineered hydrogels after being transplanted into the target sites. The incorporation of EPCs into the hydrogel can last the retention time, long-term survival, on-target delivery effects, migration and differentiation into mature endothelial cells. Despite these advantages, further modifications are mandatory to increase the dynamic growth and angiogenesis potential of EPCs in in vitro and in vivo conditions. Chemical modifications of distinct composites with distinct physical properties can yield better regenerative potential and angiogenesis during several pathologies. Here, we aimed to collect recent findings related to the application of EPCs in engineered vascular grafts and/or hydrogels for improving vascularization in the grafts. Data from the present article can help us in the application of EPCs as valid cell sources in the tissue engineering of several ischemic tissues.

Sinus Floor Augmentation with Synthetic Hydroxyapatite (NanoBone®) in Combination with Platelet-Rich Fibrin: A Case Series.

Several techniques have been described for maxillary sinus graft augmentation, including the lateral window technique and crestal approach with osteotomes or osseodensification. Platelet-rich fibrin has been used in maxillary sinus lift procedures due to its ability to accelerate soft and hard tissue healing. The aim of this study was to evaluate the potential of PRF in combination with the synthetic hydroxyapatite NanoBone® to enhance bone regeneration in sinus floor elevation with the lateral window technique. Out of the 50 individuals screened in a preoperative assessment visit from the CESPU-Famalicão clinical unit and intervened upon between January 2023 and December 2023, only 6 patients who met the study's inclusion criteria consented to participate. In a split-mouth study, twelve sinus graft surgeries were carried out. Our observations reveal that for the test group (NanoBone®/PRF), there is a 27.5 ± 4.9% increase new vital bone, 23.0 ± 3.7% increase in inert bone particles, and 49.4 ± 2.8% increase in connective tissue. Meanwhile, for the control group (NanoBone®), there is a 19.5 ± 3.0% increase in new vital bone, 23.4 ± 5.7% increase in inert bone particles, and 57.0 ± 3.5% increase in connective tissue. The results strongly indicate that mixing liquid PRF with NanoBone® does not have a negative influence on the amount of viable bone formation, and it seems to slightly increase the amount of new bone formation and revascularization in sinus bone graft procedures with the lateral window technique compared to the single use of NanoBone®.

An NIR-propelled janus nanomotor with enhanced ROS-scavenging, immunomodulating and biofilm-eradicating capacity for periodontitis treatment

Periodontitis is an inflammatory disease caused by bacterial biofilms, which leads to the destruction of periodontal tissue. Current treatments, such as mechanical cleaning and antibiotics, struggle to effectively address the persistent biofilms, inflammation, and tissue damage. A new approach involves developing a Janus nanomotor (J-CeM@Au) by coating cerium dioxide-doped mesoporous silica (CeM) with gold nanoparticles (AuNPs). This nanomotor exhibits thermophoretic motion when exposed to near-infrared (NIR) laser light due to the temperature gradient produced by the photothermal effects of asymmetrically distributed AuNPs. The NIR laser provides the energy for propulsion and activates the nanomotor's antibacterial properties, allowing it to penetrate biofilms and kill bacteria. Additionally, the nanomotor's ability to scavenge reactive oxygen species (ROS) can modulate the immune response and create a regenerative environment, promoting the healing of periodontal tissue. Overall, this multifunctional nanomotor offers a promising new approach for treating periodontitis by simultaneously addressing biofilm management and immune modulation with autonomous movement.

PRF Lysates Modulate Chemokine Expression in Oral Squamous Carcinoma and Healthy Epithelial Cells.

Platelet-rich fibrin (PRF), originally used to support soft tissue healing, is also considered a therapeutic option for treating oral lichen planus and leukoplakia. The progression from the two premalignant lesions to the aggressive malignant oral squamous cell carcinoma involves an inflammatory process linked to chemokine expression. Thus, there is a rationale for studying how PRF modulates the expression of chemokines in oral squamous carcinoma cells. To this aim, we expose the oral squamous carcinoma cell line HSC2 to IL1β and TNFα either alone or in the presence of lysates obtained from solid PRF membranes. We report here that in HSC2 cells, PRF lysates significantly reduce the forced transcription of chemokines, e.g., CXCL1, CXCL2, CXCL8, CXCL10, and CCL5. Moreover, PRF lysates attenuate the nuclear translocation of p65 in HSC2 oral epithelial cells when exposed to IL1β and TNFα. PRF lysates further reduce chemokine expression provoked by poly:IC HMW. Even though less pronounced, PRF lysates reduce IL1β- and TNFα-induced chemokine expression in TR146 cells. In primary oral epithelial cells, however, PRF lysates increase the basal expression of CXCL1, CXCL2 and CXCL8. Thus, PRF can exert a biphasic effect on chemokine expression in oral squamous cell carcinoma cell lines and primary oral epithelial cells. These findings suggest that PRF may reduce inflammation in a malignant environment while provoking an immunological response in healthy oral epithelium.

The expression of immune response genes in patients with chronic Chagas disease is shifted toward the levels observed in healthy subjects as a result of treatment with Benznidazole.

Chagas disease, caused by the Trypanosoma cruzi parasite infection, is a potentially life-threatening neglected tropical disease with a worldwide distribution. During the chronic phase of the disease, there exists a fragile balance between the host immune response and parasite replication that keeps patients in a clinically-silent asymptomatic stage for years or even decades. However, in 40% of patients, the disease progresses to clinical manifestations mainly affecting and compromising the cardiac system. Treatment is recommended in the chronic phase, although there are no early markers of its effectiveness. The aim of this study is to identify differential expression changes in genes involved in the immune response in antigen-restimulated PBMC from chronic patients with Chagas disease due to benznidazole treatment. Thus, high-throughput real-time qPCR analysis has been performed to simultaneously determine global changes in the expression of 106 genes involved in the immune response in asymptomatic (IND) and early cardiac manifestations (CCC I) Chagas disease patients pre- and post-treatment with benznidazole. The results revealed that 7 out of the 106 analyzed genes were differentially expressed (4 up- and 3 downregulated) after treatment in IND patients and 15 out of 106 (3 up- and 12 downregulated) after treatment of early cardiac Chagas disease patients. Particularly in CCC I patients, regulation of the expression level of some of these genes towards a level similar to that of healthy subjects suggests a beneficial effect of treatment and supports recommendation of benznidazole administration to early cardiac Chagas disease patients. The data obtained also demonstrated that both in asymptomatic patients and in early cardiac chronic patients, after treatment with benznidazole there is a negative regulation of the proinflammatory and cytotoxic responses triggered as a consequence of T. cruzi infection and the persistence of the parasite. This downregulation of the immune response likely prevents marked tissue damage and healing in early cardiac patients, suggesting its positive effect in controlling the pathology.

Enhancing Physiotherapy Outcomes with Photobiomodulation: A Comprehensive Review

Physiotherapy treatments employ complex approaches tailored to the patient’s diagnosis. Exercise is the primary strategy to enhance rehabilitation processes for most individuals. However, electrophysical agents, such as Photobiomodulation (PBM), that utilize specific wavelengths of light to penetrate tissues and stimulate cellular activity, can modulate various biological processes and may improve physiotherapy outcomes. This non-invasive treatment can reduce pain and inflammation, promote tissue repair, and accelerate tissue healing. Currently, PBM has numerous applications, including pain and inflammation treatment, wound healing (such as diabetic foot ulcers, pressure ulcers, post-surgery wounds, and skin grafts in burn injuries), and the management of musculoskeletal disorders (such as arthritis, tendinopathies, muscle injuries, and spinal disorders). It is also utilized to improve muscle performance and recovery in rehabilitation and sports. Additionally, transcranial PBM has shown promise in enhancing neurorehabilitative processes by facilitating the recovery of cognitive and motor functions in various types of lesions. The safety and efficacy of this treatment allow it to be incorporated alongside regular exercises and manual therapies as an adjunctive treatment, potentially enhancing outcomes in different areas of rehabilitation.

Establishment and characterization of a rat model of scalp-cranial composite defect for multilayered tissue engineering.

Composite cranial defects have individual functional and aesthetic ramifications, as well as societal burden, while posing significant challenges for reconstructive surgeons. Single-stage composite reconstruction of these deformities entail complex surgeries that bear many short- and long-term risks and complications. Current research on composite scalp-cranial defects is sparse and one-dimensional, often focusing solely on bone or skin. Thus, there is an unmet need for a simple, clinically relevant composite defect model in rodents, where there is a challenge in averting healing of the skin component via secondary intention. By utilizing a customizable (3D-printed) wound obturator, the scalp wound can be rendered non-healing for a long period (more than 6 weeks), with the cranial defect patent. The wound obturator shows minimal biotoxicity and will not cause severe endocranium-granulation adhesion. This composite defect model effectively slowed the scalp healing process and preserved the cranial defect, embodying the characteristics of a "chronic composite defect". In parallel, an autologous reconstruction model was established as the positive control. This positive control exhibited reproducible healing of the skin within 3 weeks with variable degrees of osseointegration, consistent with clinical practice. Both models provide a stable platform for subsequent research not only for composite tissue engineering and scaffold design but also for mechanistic studies of composite tissue healing.

Inhibition of Protease-Activated Receptor-2 Activation in Parkinson's Disease Using 1-Piperidin Propionic Acid.

In Parkinson's disease, neuroinflammation is a double-edged sword; when inflammation occurs it can have harmful effects, despite its important role in battling infections and healing tissue. Once triggered by microglia, astrocytes acquire a reactive state and shift from supporting the survival of neurons to causing their destruction. Activated microglia and Proteinase-activated receptor-2 (PAR2) are key points in the regulation of neuroinflammation. 1-Piperidin Propionic Acid (1-PPA) has been recently described as a novel inhibitor of PAR2. The aim of our study was to evaluate the effect of 1-PPA in neuroinflammation and microglial activation in Parkinson's disease. Protein aggregates and PAR2 expression were analyzed using Thioflavin S assay and immunofluorescence in cultured human fibroblasts from Parkinson's patients, treated or untreated with 1-PPA. A significant decrease in amyloid aggregates was observed after 1-PPA treatment in all patients. A parallel decrease in PAR2 expression, which was higher in sporadic Parkinson's patients, was also observed both at the transcriptional and protein level. In addition, in mouse LPS-activated microglia, the inflammatory profile was significantly downregulated after 1-PPA treatment, with a remarkable decrease in IL-1β, IL-6, and TNF-α, together with a decreased expression of PAR2. In conclusion, 1-PPA determines the reduction in neuroglia inflammation and amyloid aggregates formation, suggesting that the pharmacological inhibition of PAR2 could be proposed as a novel strategy to control neuroinflammation.

Deciphering the fate of granulation tissue in the human inflammatory alveolar microenvironment using single-cell RNA sequencing

Objective: To investigate the cellular composition and heterogeneity of granulation tissue in human alveolar sockets and construct single-cell transcriptomic maps to elucidate the potential outcomes of natural resolution in the inflammatory microenvironment. Methods: Granulation tissues from 12 alveolar sockets undergoing tooth extraction due to periodontitis and scheduled for delayed site preservation or autologous tooth transplantation were collected in the Department of Oral and Maxillofacial Surgery, School of stomatology Fourth Military Medical University from September 2022 to August 2023. This study used HE staining and single-cell RNA sequencing (scRNA-seq) to observe the cellular composition and morphological changes of different types of granulation tissues. This approach enabled us to identify cellular sequence variations in the inflammatory dental alveolar granulation tissue within specific microenvironments, construct single-cell atlases for different types of human dental alveolar granulation tissues, and explore the spatiotemporal patterns of cell type distribution and key gene changes during the resolution process of inflammatory granulation tissue. Results: HE staining revealed extensive infiltration of inflammatory cells in the dental alveolar inflammatory granulation tissue. After allowing the inflammatory granulation tissue to naturally resolve for three weeks, its histological morphology was essentially consistent with that of reparative granulation tissue. ScRNA-seq captured a total of 20 448 cells from granulation tissues, and the gene expression quantification analysis revealed total gene counts of 33 835 for inflammatory granulation tissue, 36 058 for naturally resolved granulation tissue, and 34 719 for reparative granulation tissue. At the single-cell level, granulation tissue was annotated into ten cell subgroups, including vascular endothelial cells, mesenchymal stem cells, and fibroblasts. Differences were observed in the proportion of cell compositions between inflammatory and naturally resolved granulation tissues. Pseudo-temporal analysis illustrated two main outcomes in tissue resolution and healing, involving immune responses and angiogenesis. Among these, genes associated with inflammation regulation and immune response, such as Igbp5, Zfp36, and Hspa1b, as well as genes involved in extracellular matrix secretion and the formation of vessels and fibers such as Timp3, Postn, and Rgs5, showed significant differences in expression between the two types of granulation tissues. Conclusions: Inflammatory granulation tissue exhibits heterogeneity in cell composition, gene expression, and biological functions compared to naturally resolved granulation tissue. When the inflammatory granulation tissue in the alveolar socket is left undisturbed to undergo natural resolution, it displays a cellular composition similar to that of reparative granulation tissue at both the histological and single-cell levels. Moreover, it modulates the inflammatory response and the healing process through immune reactions and tissue remodeling.