Fibrin Sealant Derived from Human Plasma as a Scaffold for Bone Grafts Associated with Photobiomodulation Therapy

Exosomes derived from platelet-rich plasma present a novel potential in repairing knee articular cartilage defect combined with cyclic peptide-modified β-TCP scaffold

BACKGROUND

The aim of this study was to investigate the therapeutic effects and mechanisms of PRP-exos combined with cyclic peptide-modified β-TCP scaffold in the treatment of rabbit knee cartilage defect.

METHODS

PRP-exos were extracted and characterized by TEM, NTA and WB. The therapeutic effects were evaluated by ICRS score, HE staining, Immunohistochemistry, qRT-PCR and ELISA. The repair mechanism of PRP-exos was estimated and predicted by miRNA sequencing analysis and protein-protein interaction network analysis.

RESULTS

The results showed that PRP-exos had a reasonable size distribution and exhibited typical exosome morphology. The combination of PRP-exos and cyclic peptide-modified β-TCP scaffold improved ICRS score and the expression level of COL-2, RUNX2, and SOX9. Moreover, this combination therapy reduced the level of MMP-3, TNF-α, IL-1β, and IL-6, while increasing the level of TIMP-1. In PRP-exos miRNA sequencing analysis, the total number of known miRNAs aligned across all samples was 252, and a total of 91 differentially expressed miRNAs were detected. The results of KEGG enrichment analysis and the protein-protein interaction network analysis indicated that the PI3K/AKT signaling pathway could impact the function of chondrocytes by regulating key transcription factors to repair cartilage defect.

CONCLUSION

PRP-exos combined with cyclic peptide-modified β-TCP scaffold effectively promoted cartilage repair and improved chondrocyte function in rabbit knee cartilage defect. Based on the analysis and prediction of PRP-exos miRNAs sequencing, PI3K/AKT signaling pathway may contribute to the therapeutic effect. These findings provide experimental evidence for the application of PRP-exos in the treatment of cartilage defect.

Tailoring photobiomodulation to enhance tissue regeneration

Photobiomodulation (PBM), the use of biocompatible tissue-penetrating light to interact with intracellular chromophores to modulate the fates of cells and tissues, has emerged as a promising non-invasive approach to enhancing tissue regeneration. Unlike photodynamic or photothermal therapies that require the use of photothermal agents or photosensitizers, PBM treatment does not need external agents. With its non-harmful nature, PBM has demonstrated efficacy in enhancing molecular secretions and cellular functions relevant to tissue regeneration. The utilization of low-level light from various sources in PBM targets cytochrome c oxidase, leading to increased synthesis of adenosine triphosphate, induction of growth factor secretion, activation of signaling pathways, and promotion of direct or indirect gene expression. When integrated with stem cell populations, bioactive molecules or nanoparticles, or biomaterial scaffolds, PBM proves effective in significantly improving tissue regeneration. This review consolidates findings from in vitro, in vivo, and human clinical outcomes of both PBM alone and PBM-combined therapies in tissue regeneration applications. It encompasses the background of PBM invention, optimization of PBM parameters (such as wavelength, irradiation, and exposure time), and understanding of the mechanisms for PBM to enhance tissue regeneration. The comprehensive exploration concludes with insights into future directions and perspectives for the tissue regeneration applications of PBM.

Photobiomodulation and mesenchymal stem cell-conditioned medium for the repair of experimental critical-size defects

Orthopedic surgeons face a significant challenge in treating critical-size femoral defects (CSFD) caused by osteoporosis (OP), trauma, infection, or bone tumor resections. In this study for the first time, the application of photobiomodulation (PBM) and bone marrow mesenchymal stem cell-conditioned medium (BM-MSC-CM) to improve the osteogenic characteristics of mineralized bone scaffold (MBS) in ovariectomy-induced osteoporotic (OVX) rats with a CSFD was tested. Five groups of OVX rats with CSFD were created: (1) Control (C); (2) MBS; (3) MBS + CM; (4) MBS + PBM; (5) MBS + CM + PBM. Computed tomography scans (CT scans), compression indentation tests, and histological and stereological analyses were carried out after euthanasia at 12 weeks following implantation surgery. The CT scan results showed that CSFD in the MBS + CM, MBS + PBM, and MBS + CM + PBM groups was significantly smaller compared to the control group (p = 0.01, p = 0.04, and p = 0.000, respectively). Moreover, the CSFD size was substantially smaller in the MBS + CM + PBM treatment group than in the MBS, MBS + CM, and MBS + PBM treatment groups (p = 0.004, p = 0.04, and p = 0.01, respectively). The MBS + PBM and MBS + CM + PBM treatments had significantly increased maximum force relative to the control group (p = 0.01 and p = 0.03, respectively). Bending stiffness significantly increased in MBS (p = 0.006), MBS + CM, MBS + PBM, and MBS + CM + PBM treatments (all p = 0.004) relative to the control group. All treatment groups had considerably higher new trabecular bone volume (NTBV) than the control group (all, p = 0.004). Combined therapies with MBS + PBM and MBS + CM + PBM substantially increased the NTBV relative to the MBS group (all, p = 0.004). The MBS + CM + PBM treatment had a markedly higher NTBV than the MBS + PBM (p = 0.006) and MBS + CM (p = 0.004) treatments. MBS + CM + PBM, MBS + PBM, and MBS + CM treatments significantly accelerated bone regeneration of CSFD in OVX rats. PBM + CM enhanced the osteogenesis of the MBS compared to other treatment groups.

Fabricating the multibranch carboxyl-modified cellulose for hemorrhage control

Excessive bleeding is associated with a high mortality risk. In this study, citric acid and ascorbic acid were sequentially modified on the surface of microcrystalline cellulose (MCAA) to increase its carboxyl content, and their potential as hemostatic materials was investigated. The MCAA exhibited a carboxylic group content of 9.52 %, higher than that of citric acid grafted microcrystalline cellulose (MCA) at 4.6 %. Carboxyl functionalization of microcrystalline cellulose surfaces not only plays a fundamental role in the structure of composite materials but also aids in the absorption of plasma and stimulation of platelets. Fourier -transform infrared (FT-IR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) spectra confirmed that carboxyl groups were successfully introduced onto the cellulose surface. Physical properties tests indicated that the MCAA possessed higher thermal stability (Tmax = 472.2 °C) compared to microcrystalline cellulose (MCC). Additionally, in vitro hemocompatibility, cytotoxicity and hemostatic property results demonstrated that MCAA displayed good biocompatibility (hemolysis ratio <1 %), optimal cell compatibility (cell viability exceeded 100 % after 72 h incubation), and impressive hemostatic effect (BCIMCAA = 31.3 %). Based on these findings, the hemostatic effect of covering a wound with MCAA was assessed, revealing enhanced hemostatic properties using MCAA in tail-amputation and liver-injury hemorrhage models. Furthermore, exploration into hemostatic mechanisms revealed that MCAA can significantly accelerate coagulation through rapid platelet aggregation and activation of the clotting cascade. Notably, MCAA showed remarkable biocompatibility and induced minimal skin irritation. In conclusion, the results affirmed that MCAA is a safe and potentially effective hemostatic agent for hemorrhage control.

Photobiomodulation Therapy Improves Repair of Bone Defects Filled by Inorganic Bone Matrix and Fibrin Heterologous Biopolymer

Biomaterials are used extensively in graft procedures to correct bone defects, interacting with the body without causing adverse reactions. The aim of this pre-clinical study was to analyze the effects of photobiomodulation therapy (PBM) with the use of a low-level laser in the repair process of bone defects filled with inorganic matrix (IM) associated with heterologous fibrin biopolymer (FB). A circular osteotomy of 4 mm in the left tibia was performed in 30 Wistar male adult rats who were randomly divided into three groups: G1 = IM + PBM, G2 = IM + FB and G3 = IM + FB + PBM. PBM was applied at the time of the experimental surgery and three times a week, on alternate days, until euthanasia, with 830 nm wavelength, in two points of the operated site. Five animals from each group were euthanized 14 and 42 days after surgery. In the histomorphometric analysis, the percentage of neoformed bone tissue in G3 (28.4% ± 2.3%) was higher in relation to G1 (24.1% ± 2.91%) and G2 (22.2% ± 3.11%) at 14 days and at 42 days, the percentage in G3 (35.1% ± 2.55%) was also higher in relation to G1 (30.1% ± 2.9%) and G2 (31.8% ± 3.12%). In the analysis of the birefringence of collagen fibers, G3 showed a predominance of birefringence between greenish-yellow in the neoformed bone tissue after 42 days, differing from the other groups with a greater presence of red-orange fibers. Immunohistochemically, in all experimental groups, it was possible to observe immunostaining for osteocalcin (OCN) near the bone surface of the margins of the surgical defect and tartrate-resistant acid phosphatase (TRAP) bordering the newly formed bone tissue. Therefore, laser photobiomodulation therapy contributed to improving the bone repair process in tibial defects filled with bovine biomaterial associated with fibrin biopolymer derived from snake venom.

In Vivo Evaluation of Collagen and Chitosan Scaffold, Associated or Not with Stem Cells, in Bone Repair

Natural polymers are increasingly being used in tissue engineering due to their ability to mimic the extracellular matrix and to act as a scaffold for cell growth, as well as their possible combination with other osteogenic factors, such as mesenchymal stem cells (MSCs) derived from dental pulp, in an attempt to enhance bone regeneration during the healing of a bone defect. Therefore, the aim of this study was to analyze the repair of mandibular defects filled with a new collagen/chitosan scaffold, seeded or not with MSCs derived from dental pulp. Twenty-eight rats were submitted to surgery for creation of a defect in the right mandibular ramus and divided into the following groups: G1 (control group; mandibular defect with clot); G2 (defect filled with dental pulp mesenchymal stem cells-DPSCs); G3 (defect filled with collagen/chitosan scaffold); and G4 (collagen/chitosan scaffold seeded with DPSCs). The analysis of the scaffold microstructure showed a homogenous material with an adequate percentage of porosity. Macroscopic and radiological examination of the defect area after 6 weeks post-surgery revealed the absence of complete repair, as well as absence of signs of infection, which could indicate rejection of the implants. Histomorphometric analysis of the mandibular defect area showed that bone formation occurred in a centripetal fashion, starting from the borders and progressing towards the center of the defect in all groups. Lower bone formation was observed in G1 when compared to the other groups and G2 exhibited greater osteoregenerative capacity, followed by G4 and G3. In conclusion, the scaffold used showed osteoconductivity, no foreign body reaction, malleability and ease of manipulation, but did not obtain promising results for association with DPSCs.

Novel Local "Off-the-Shelf" Immunotherapy for the Treatment of Myeloma Bone Disease

Myeloma bone disease (MBD) is one of the major complications in multiple myeloma (MM)-the second most frequent hematologic malignancy. It is characterized by the formation of bone lesions due to the local action of proliferating MM cells, and to date, no effective therapy has been developed. In this study, we propose a novel approach for the local treatment of MBD with a combination of natural killer cells (NKs) and mesenchymal stem cells (MSCs) within a fibrin scaffold, altogether known as FINM. The unique biological properties of the NKs and MSCs, joined to the injectable biocompatible fibrin, permitted to obtain an efficient "off-the-shelf" ready-to-use composite for the local treatment of MBD. Our in vitro analyses demonstrate that NKs within FINM exert a robust anti-tumor activity against MM cell lines and primary cells, with the capacity to suppress osteoclast activity (~60%) within in vitro 3D model of MBD. Furthermore, NKs' post-thawing cytotoxic activity is significantly enhanced (~75%) in the presence of MSCs, which circumvents the decrease of NKs cytotoxicity after thawing, a well-known issue in the cryopreservation of NKs. To reduce the tumor escape, we combined FINM with other therapeutic agents (bortezomib (BZ), and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)), observing a clear therapeutic synergistic effect in vitro. Finally, the therapeutic efficacy of FINM in combination with BZ and TRAIL was assessed in a mouse model of MM, achieving 16-fold smaller tumors compared to the control group without treatment. These results suggest the potential of FINM to serve as an allogeneic "off-the-shelf" approach to improve the outcomes of patients suffering from MBD.

Tissue Bioengineering with Fibrin Scaffolds and Deproteinized Bone Matrix Associated or Not with the Transoperative Laser Photobiomodulation Protocol

Extending the range of use of the heterologous fibrin biopolymer, this pre-clinical study showed a new proportionality of its components directed to the formation of scaffold with a lower density of the resulting mesh to facilitate the infiltration of bone cells, and combined with therapy by laser photobiomodulation, in order to accelerate the repair process and decrease the morphofunctional recovery time. Thus, a transoperative protocol of laser photobiomodulation (L) was evaluated in critical bone defects filled with deproteinized bovine bone particles (P) associated with heterologous fibrin biopolymer (HF). The groups were: BC_L (blood clot + laser); HF; HF_L; PHF (P+HF); PHF_L (P+HF+L). Microtomographically, bone volume (BV) at 14 days, was higher in the PHF and PHF_L groups (10.45 ± 3.31 mm³ and 9.94 ± 1.51 mm³), significantly increasing in the BC_L, HF_L and PHF_L groups. Histologically, in all experimental groups, the defects were not reestablished either in the external cortical bone or in the epidural, occurring only in partial bone repair. At 42 days, the bone area (BA) increased in all groups, being significantly higher in the laser-treated groups. The quantification of bone collagen fibers showed that the percentage of collagen fibers in the bone tissue was similar between the groups for each experimental period, but significantly higher at 42 days (35.71 ± 6.89%) compared to 14 days (18.94 ± 6.86%). It can be concluded that the results of the present study denote potential effects of laser radiation capable of inducing functional bone regeneration, through the synergistic combination of biomaterials and the new ratio of heterologous fibrin biopolymer components (1:1:1) was able to make the resulting fibrin mesh less dense and susceptible to cellular permeability. Thus, the best fibrinogen concentration should be evaluated to find the ideal heterologous fibrin scaffold.

Use of Photobiomodulation Combined with Fibrin Sealant and Bone Substitute Improving the Bone Repair of Critical Defects

In this preclinical protocol, an adjunct method is used in an attempt to overcome the limitations of conventional therapeutic approaches applied to bone repair of large bone defects filled with scaffolds. Thus, we evaluate the effects of photobiomodulation therapy (PBMT) on the bone repair process on defects filled with demineralized bovine bone (B) and fibrin sealant (T). The groups were BC (blood clot), BT (B + T), BCP (BC + PBMT), and BTP (B + T + PBMT). Microtomographically, BC and BCP presented a hypodense cavity with hyperdense regions adjacent to the border of the wound, with a slight increase at 42 days. BT and BTP presented discrete hyperdensing areas at the border and around the B particles. Quantitatively, BCP and BTP (16.96 ± 4.38; 17.37 ± 4.38) showed higher mean bone density volume in relation to BC and BT (14.42 ± 3.66; 13.44 ± 3.88). Histologically, BC and BCP presented deposition of immature bone at the periphery and at 42 days new bone tissue became lamellar with organized total collagen fibers. BT and BTP showed inflammatory infiltrate along the particles, but at 42 days, it was resolved, mainly in BTP. In the birefringence analysis, BT and BTP, the percentage of red birefringence increased (9.14% to 20.98% and 7.21% to 27.57%, respectively), but green birefringence was similar in relation to 14 days (3.3% to 3.5% and 3.5% to 4.2%, respectively). The number of osteocytes in the neoformed bone matrix proportionally reduced in all evaluated groups. Immunostaining of bone morphogenetic protein (BMP—2/4), osteocalcin (OCN), and vascular endothelial growth factor (VEGF) were higher in BCP and BTP when compared to the BC and BT groups (p < 0.05). An increased number of TRAP positive cells (tartrate resistant acid phosphatase) was observed in BT and BTP. We conclude that PBMT positively influenced the repair of bone defects filled with B and T.

Application of Fibrin Associated with Photobiomodulation as a Promising Strategy to Improve Regeneration in Tissue Engineering: A Systematic Review

Fibrin, derived from proteins involved in blood clotting (fibrinogen and thrombin), is a biopolymer with different applications in the health area since it has hemostasis, biocompatible and three-dimensional physical structure properties, and can be used as scaffolds in tissue regeneration or drug delivery system for cells and/or growth factors. Fibrin alone or together with other biomaterials, has been indicated for use as a biological support to promote the regeneration of stem cells, bone, peripheral nerves, and other injured tissues. In its diversity of forms of application and constitution, there are platelet-rich fibrin (PRF), Leukocyte- and platelet-rich fibrin (L-PRF), fibrin glue or fibrin sealant, and hydrogels. In order to increase fibrin properties, adjuvant therapies can be combined to favor tissue repair, such as photobiomodulation (PBM), by low-level laser therapy (LLLT) or LEDs (Light Emitting Diode). Therefore, this systematic review aimed to evaluate the relationship between PBM and the use of fibrin compounds, referring to the results of previous studies published in PubMed/MEDLINE, Scopus and Web of Science databases. The descriptors “fibrin AND low-level laser therapy” and “fibrin AND photobiomodulation” were used, without restriction on publication time. The bibliographic search found 44 articles in PubMed/MEDLINE, of which 26 were excluded due to duplicity or being outside the eligibility criteria. We also found 40 articles in Web of Science and selected 1 article, 152 articles in Scopus and no article selected, totaling 19 articles for qualitative analysis. The fibrin type most used in combination with PBM was fibrin sealant, mainly heterologous, followed by PRF or L-PRF. In PBM, the gallium-aluminum-arsenide (GaAlAs) laser prevailed, with a wavelength of 830 nm, followed by 810 nm. Among the preclinical studies, the most researched association of fibrin and PBM was the use of fibrin sealants in bone or nerve injuries; in clinical studies, the association of PBM with medication-related treatments osteonecrosis of the jaw (MRONJ). Therefore, there is scientific evidence of the contribution of PBM on fibrin composites, constituting a supporting therapy that acts by stimulating cell activity, angiogenesis, osteoblast activation, axonal growth, anti-inflammatory and anti-edema action, increased collagen synthesis and its maturation, as well as biomolecules.

Suitability of Chitosan Scaffolds with Carbon Nanotubes for Bone Defects Treated with Photobiomodulation

Biomaterials have been investigated as an alternative for the treatment of bone defects, such as chitosan/carbon nanotubes scaffolds, which allow cell proliferation. However, bone regeneration can be accelerated by electrotherapeutic resources that act on bone metabolism, such as low-level laser therapy (LLLT). Thus, this study evaluated the regeneration of bone lesions grafted with chitosan/carbon nanotubes scaffolds and associated with LLLT. For this, a defect (3 mm) was created in the femur of thirty rats, which were divided into 6 groups: Control (G1/Control), LLLT (G2/Laser), Chitosan/Carbon Nanotubes (G3/C+CNTs), Chitosan/Carbon Nanotubes with LLLT (G4/C+CNTs+L), Mineralized Chitosan/Carbon Nanotubes (G5/C+CNTsM) and Mineralized Chitosan/Carbon Nanotubes with LLLT (G6/C+CNTsM+L). After 5 weeks, the biocompatibility of the chitosan/carbon nanotubes scaffolds was observed, with the absence of inflammatory infiltrates and fibrotic tissue. Bone neoformation was denser, thicker and voluminous in G6/C+CNTsM+L. Histomorphometric analyses showed that the relative percentage and standard deviations (mean ± SD) of new bone formation in groups G1 to G6 were 59.93 ± 3.04a (G1/Control), 70.83 ± 1.21b (G2/Laser), 70.09 ± 4.31b (G3/C+CNTs), 81.6 ± 5.74c (G4/C+CNTs+L), 81.4 ± 4.57c (G5/C+CNTsM) and 91.3 ± 4.81d (G6/C+CNTsM+L), respectively, with G6 showing a significant difference in relation to the other groups (a ≠ b ≠ c ≠ d; p < 0.05). Immunohistochemistry also revealed good expression of osteocalcin (OC), osteopontin (OP) and vascular endothelial growth factor (VEGF). It was concluded that chitosan-based carbon nanotube materials combined with LLLT effectively stimulated the bone healing process.

Effects of a Biocomplex Formed by Two Scaffold Biomaterials, Hydroxyapatite/Tricalcium Phosphate Ceramic and Fibrin Biopolymer, with Photobiomodulation, on Bone Repair

There are several treatment methods available for bone repair, although the effectiveness becomes limited in cases of large defects. The objective of this pre-clinical protocol was to evaluate the grafting of hydroxyapatite/tricalcium phosphate (BCP) ceramic biomaterial (B; QualyBone BCP^®, QualyLive, Amadora, Portugal) together with the heterologous fibrin biopolymer (FB; CEVAP/UNESP Botucatu, Brazil) and with photobiomodulation (PBM; Laserpulse^®, Ibramed, Amparo, Brazil) in the repair process of bone defects. Fifty-six rats were randomly divided into four groups of seven animals each: the biomaterial group (G1/B), the biomaterial plus FB group (G2/BFB); the biomaterial plus PBM group (G3/B + PBM), and the biomaterial plus FB plus PBM group (G4/BFB + PBM). After anesthesia, a critical defect was performed in the center of the rats’ parietal bones, then filled and treated according to their respective groups. The rats were euthanized at 14 and 42 postoperative days. Histomorphologically, at 42 days, the G4/BFB + PBM group showed a more advanced maturation transition, with more organized and mature bone areas forming concentric lamellae. A birefringence analysis of collagen fibers also showed a more advanced degree of maturation for the G4/BFB + PBM group. In the comparison between the groups, in the two experimental periods (14 and 42 days), in relation to the percentage of formation of new bone tissue, a significant difference was found between all groups (G1/B (5.42 ± 1.12; 21.49 ± 4.74), G2/BFB (5.00 ± 0.94; 21.77 ± 2.83), G3/B + PBM (12.65 ± 1.78; 29.29 ± 2.93), and G4/BFB + PBM (12.65 ± 2.32; 31.38 ± 2.89)). It was concluded that the use of PBM with low-level laser therapy (LLLT) positively interfered in the repair process of bone defects previously filled with the biocomplex formed by the heterologous fibrin biopolymer associated with the synthetic ceramic of hydroxyapatite and tricalcium phosphate.

Preparation of Chitosan/Clay Composites for Safe and Effective Hemorrhage Control

Uncontrolled hemorrhage from trauma or surgery can lead to death. In this study, chitosan/kaolin (CSK) and chitosan/montmorillonite (CSMMT) composites were prepared from chitosan (CS), kaolin (K), and montmorillonite (MMT) as raw materials to control bleeding. The physiochemical properties and surface morphology of CSK and CSMMT composites were analyzed by Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta potentials, and X-ray fluorescence (XRF). The hemostatic mechanism was measured in vitro by activated partial thromboplastin time (APTT), prothrombin time (PT), in vitro clotting time, erythrocyte aggregation, and thromboelastogram (TEG). The hemostasis ability was further verified by using tail amputation and arteriovenous injury models in rats. The biocompatibility of CSK and CSMMT was evaluated by in vitro hemolysis, cytotoxicity assays, as well as acute toxicity test and skin irritation tests. The results show that CSK and CSMMT are promising composite materials with excellent biocompatibility and hemostatic properties that can effectively control bleeding.

Biological Behavior of Xenogenic Scaffolds in Alcohol-Induced Rats: Histomorphometric and Picrosirius Red Staining Analysis

In this experimental protocol, the objective was to evaluate the biological behavior of two xenogenic scaffolds in alcohol-induced rats through histomorphometric and Picrosirius Red staining analysis of non-critical defects in the tibia of rats submitted or not to alcohol ingestion at 25% v/v. Eighty male rats were randomly divided into four groups (n = 20 each): CG/B (water diet + Bio-Oss® graft, Geistlich Pharma AG, Wolhusen, Switzerland), CG/O (water diet + OrthoGen® graft, Baumer, Mogi Mirim, Brazil), AG/B (25% v/v alcohol diet + Bio-Oss® graft), and AG/O (25% v/v alcohol diet + OrthoGen® graft). After 90 days of liquid diet, the rats were surgically obtained, with a defect in the tibia proximal epiphysis; filled in according to their respective groups; and euthanized at 10, 20, 40 and 60 days. In two initial periods (10 and 20 days), all groups presented biomaterial particles surrounded by disorganized collagen fibrils. Alcoholic animals (AG/B and AG/O) presented, in the cortical and medullary regions, a reactive tissue with inflammatory infiltrate. In 60 days, in the superficial area of the surgical cavities, particles of biomaterials were observed in all groups, with new compact bone tissue around them, without complete closure of the lesion, except in non-alcoholic animals treated with Bio-Oss® xenograft (CG/B), where the new cortical interconnected the edges of the defect. Birefringence transition was observed in the histochemical analysis of collagen fibers by Picrosirius Red, in which all groups in periods of 10 and 20 days showed red-orange birefringence, and from 40 days onwards greenish-yellow birefringence, which demonstrates the characteristic transition from the formation of thin and disorganized collagen fibers initially to more organized and thicker later. In histomorphometric analysis, at 60 days, CG/B had the highest volume density of new bone (32.9 ± 1.15) and AG/O the lowest volume density of new bone (15.32 ± 1.71). It can be concluded that the bone neoformation occurred in the defects that received the two biomaterials, in all periods, but the Bio-Oss® was superior in the results, with its groups CG/B and AG/B displaying greater bone formation (32.9 ± 1.15 and 22.74 ± 1.15, respectively) compared to the OrthoGen® CG/O and AG/O groups (20.66 ± 2.12 and 15.32 ± 1.71, respectively), and that the alcoholic diet interfered negatively in the repair process and in the percentage of new bone formed.

In Vivo Study of Nasal Bone Reconstruction with Collagen, Elastin and Chitosan Membranes in Abstainer and Alcoholic Rats

The aim of the present study was to evaluate the use of collagen, elastin, or chitosan biomaterial for bone reconstruction in rats submitted or not to experimental alcoholism. Wistar male rats were divided into eight groups, submitted to chronic alcohol ingestion (G5 to G8) or not (G1 to G4). Nasal bone defects were filled with clot in animals of G1 and G5 and with collagen, elastin, and chitosan grafts in G2/G6, G3/G7, and G4/G8, respectively. Six weeks after, all specimens underwent radiographic, tomographic, and microscopic evaluations. Bone mineral density was lower in the defect area in alcoholic animals compared to the abstainer animals. Bone neoformation was greater in the abstainer groups receiving the elastin membrane and in abstainer and alcoholic rats receiving the chitosan membrane (15.78 ± 1.19, 27.81 ± 0.91, 47.29 ± 0.97, 42.69 ± 1.52, 13.81 ± 1.60, 18.59 ± 1.37, 16.54 ± 0.89, and 37.06 ± 1.17 in G1 to G8, respectively). In conclusion, osteogenesis and bone density were more expressive after the application of the elastin matrix in abstainer animals and of the chitosan matrix in both abstainer and alcoholic animals. Chronic alcohol ingestion resulted in lower bone formation and greater formation of fibrous connective tissue.

Prospects and Applications of Natural Blood-Derived Products in Regenerative Medicine

Currently, there are a number of therapeutic schemes used for the treatment of various types of musculoskeletal disorders. However, despite the use of new treatment options, therapeutic failure remains common due to impaired and delayed healing, or implant rejection. Faced with this challenge, in recent years regenerative medicine started looking for alternative solutions that could additionally support tissue regeneration. This review aims to outline the functions and possible clinical applications of, and future hopes associated with, using autologous or heterologous products such as antimicrobial peptides (AMPs), microvesicles (MVs), and neutrophil degranulation products (DGP) obtained from circulating neutrophils. Moreover, different interactions between neutrophils and platelets are described. Certain products released from neutrophils are critical for interactions between different immune cells to ensure adequate tissue repair. By acting directly and indirectly on host cells, these neutrophil-derived products can modulate the body’s inflammatory responses in various ways. The development of new formulations based on these products and their clinically proven success would give hope for significant progress in regenerative therapy in human and veterinary medicine.

Photobiomodulation Therapy as a Possible New Approach in COVID-19: A Systematic Review

COVID-19 is a viral disease characterized as a pandemic by the World Health Organization in March 2020. Since then, researchers from all over the world have been looking for ways to fight this disease. Many cases of complications arise from insufficient immune responses due to low immunity, with intense release of pro-inflammatory cytokines that can damage the structure of organs such as the lung. Thus, the hypothesis arises that photobiomodulation therapy (PBMT) with the use of a low-level laser (LLLT) may be an ally approach to patients with COVID-19 since it is effective for increasing immunity, helping tissue repair, and reducing pro-inflammatory cytokines. This systematic review was performed with the use of PubMed/MEDLINE, Web of Science, Scopus and Google Scholar databases with the following keywords: "low-level laser therapy OR photobiomodulation therapy AND COVID-19". The inclusion criteria were complete articles published from January 2020 to January 2021 in English. The exclusion criteria were other languages, editorials, reviews, brief communications, letters to the editor, comments, conference abstracts, and articles that did not provide the full text. The bibliographic search found 18 articles in the Pubmed/MEDLINE database, 118 articles on the Web of Science, 23 articles on Scopus, and 853 articles on Google Scholar. Ten articles were included for qualitative synthesis, of which four commentary articles discussed the pathogenesis and the effect of PBMT in COVID-19. Two in vitro and lab experiments showed the effect of PBMT on prevention of thrombosis and positive results in wound healing during viral infection, using the intravascular irradiation (ILIB) associated with Phthalomethyl D. Two case reports showed PBMT improved the respiratory indexes, radiological findings, and inflammatory markers in severe COVID-19 patients. One case series reported the clinical improvement after PBMT on 14 acute COVID-19 patients, rehabilitation on 24 patients, and as a preventive treatment on 70 people. One clinical trial of 30 patients with severe COVID-19 who require invasive mechanical ventilation, showed PBMT-static magnetic field was not statistically different from placebo for the length of stay in the Intensive Care Unit, but improved diaphragm muscle function and ventilation and decreased the inflammatory markers. This review suggests that PBMT may have a positive role in treatment of COVID-19. Still, the necessity for more clinical trials remains in this field and there is not sufficient research evidence regarding the effects of PBMT and COVID-19 disease, and there is a large gap.

Osseointegration Improvement of Co-Cr-Mo Alloy Produced by Additive Manufacturing

Cobalt-base alloys (Co-Cr-Mo) are widely employed in dentistry and orthopedic implants due to their biocompatibility, high mechanical strength and wear resistance. The osseointegration of implants can be improved by surface modification techniques. However, complex geometries obtained by additive manufacturing (AM) limits the efficiency of mechanical-based surface modification techniques. Therefore, plasma immersion ion implantation (PIII) is the best alternative, creating nanotopography even in complex structures. In the present study, we report the osseointegration results in three conditions of the additively manufactured Co-Cr-Mo alloy: (i) as-built, (ii) after PIII, and (iii) coated with titanium (Ti) followed by PIII. The metallic samples were designed with a solid half and a porous half to observe the bone ingrowth in different surfaces. Our results revealed that all conditions presented cortical bone formation. The titanium-coated sample exhibited the best biomechanical results, which was attributed to the higher bone ingrowth percentage with almost all medullary canals filled with neoformed bone and the pores of the implant filled and surrounded by bone ingrowth. It was concluded that the metal alloys produced for AM are biocompatible and stimulate bone neoformation, especially when the Co-28Cr-6Mo alloy with a Ti-coated surface, nanostructured and anodized by PIII is used, whose technology has been shown to increase the osseointegration capacity of this implant.

In Vivo Biological Behavior of Polymer Scaffolds of Natural Origin in the Bone Repair Process

Autologous bone grafts, used mainly in extensive bone loss, are considered the gold standard treatment in regenerative medicine, but still have limitations mainly in relation to the amount of bone available, donor area, morbidity and creation of additional surgical area. This fact encourages tissue engineering in relation to the need to develop new biomaterials, from sources other than the individual himself. Therefore, the present study aimed to investigate the effects of an elastin and collagen matrix on the bone repair process in critical size defects in rat calvaria. The animals (Wistar rats, n = 30) were submitted to a surgical procedure to create the bone defect and were divided into three groups: Control Group (CG, n = 10), defects filled with blood clot; E24/37 Group (E24/37, n = 10), defects filled with bovine elastin matrix hydrolyzed for 24 h at 37 °C and C24/25 Group (C24/25, n = 10), defects filled with porcine collagen matrix hydrolyzed for 24 h at 25 °C. Macroscopic and radiographic analyses demonstrated the absence of inflammatory signs and infection. Microtomographical 2D and 3D images showed centripetal bone growth and restricted margins of the bone defect. Histologically, the images confirmed the pattern of bone deposition at the margins of the remaining bone and without complete closure by bone tissue. In the morphometric analysis, the groups E24/37 and C24/25 (13.68 ± 1.44; 53.20 ± 4.47, respectively) showed statistically significant differences in relation to the CG (5.86 ± 2.87). It was concluded that the matrices used as scaffolds are biocompatible and increase the formation of new bone in a critical size defect, with greater formation in the polymer derived from the intestinal serous layer of porcine origin (C24/25).

Photobiomodulation Therapy on the Guided Bone Regeneration Process in Defects Filled by Biphasic Calcium Phosphate Associated with Fibrin Biopolymer

The aim is to evaluate the effects of photobiomodulation therapy (PBMT) on the guided bone regeneration process (GBR) in defects in the calvaria of rats filled with biphasic calcium phosphate associated with fibrin biopolymer. Thirty male Wistar rats were randomly separated: BMG (n = 10), defects filled with biomaterial and covered by membrane; BFMG (n = 10), biomaterial and fibrin biopolymer covered by membrane; and BFMLG (n = 10), biomaterial and fibrin biopolymer covered by membrane and biostimulated with PBMT. The animals were euthanized at 14 and 42 days postoperatively. Microtomographically, in 42 days, there was more evident bone growth in the BFMLG, limited to the margins of the defect with permanence of the particles. Histomorphologically, an inflammatory infiltrate was observed, which regressed with the formation of mineralized bone tissue. In the quantification of bone tissue, all groups had a progressive increase in new bone tissue with a significant difference in which the BFMLG showed greater bone formation in both periods (10.12 ± 0.67 and 13.85 ± 0.54), followed by BFMG (7.35 ± 0.66 and 9.41 ± 0.84) and BMG (4.51 ± 0.44 and 7.11 ± 0.44). Picrosirius-red staining showed greater birefringence of collagen fibers in yellow-green color in the BFMLG, showing more advanced bone maturation. PBMT showed positive effects capable of improving and accelerating the guided bone regeneration process when associated with biphasic calcium phosphate and fibrin biopolymer.

Effects of photobiomodulation on bone defects grafted with bone substitutes: A systematic review of in vivo animal studies

A present, photobiomodulation therapy (PBMT) effectiveness in enhancing bone regeneration in bone defects grafted with or without biomaterials is unclear. This systematic review (PROSPERO, ref. CRD 42019148959) aimed to critically appraise animal in vivo published data and present the efficacy of PBMT and its potential synergistic effects on grafted bone defects. MEDLINE, CCCT, Scopus, Science Direct, Google Scholar, EMBASE, EBSCO were searched, utilizing the following keywords: bone repair; low-level laser therapy; LLLT; light emitting diode; LEDs; photobiomodulation therapy; in vivo animal studies, bone substitutes, to identify studies between 1994 and 2019. After applying the eligibility criteria, 38 papers included where the results reported according to "PRISMA." The results revealed insufficient and incomplete PBM parameters, however, the outcomes with or without biomaterials have positive effects on bone healing. In conclusion, in vivo animal studies with a standardized protocol to elucidate the effects of PBMT on biomaterials are required initially prior to clinical studies.

Photobiomodulation Therapy on Orthodontic Movement: Analysis of Preliminary Studies with a New Protocol

This study aimed to investigate the effectiveness of photobiomodulation therapy (PBMT) on the acceleration of orthodontic movements, deriving from its biostimulating and regenerative capacity on soft tissues, consequent to the increase in differentiation, proliferation, and activity of cells that are involved with alveolar bone remodeling. The present randomized controlled trial was conducted on six patients who required extractive orthodontic therapy because their ectopic canines had erupted. A total of eight canines were analyzed, four of which received laser irradiation (i.e., experimental group). Two weeks after the extractions, all canines of the experimental and placebo groups were distalized simultaneously and symmetrically with the laceback retraction technique. The PBMT protocol consisted of four cycles of laser applications, one each on days 0, 3, 7, and 14 of the study, with session treatment durations of 2–4 min. The results of the descriptive analysis on the distal displacement speed of the canines after 1 month of follow-up indicate an average displacement of 1.35 mm for the non-irradiated group and 1.98 mm for the irradiated group. Through inferential analysis, a statistically significant difference (p < 0.05) was found between the average speed of the irradiated canines and the control canines. The low energy density laser used in this study, with the parameters set, was found to be a tool capable of statistically significantly accelerating the distal displacement of canines.

Elastin-derived scaffolding associated or not with bone morphogenetic protein (BMP) or hydroxyapatite (HA) in the repair process of metaphyseal bone defects

Tissue engineering represents a promising alternative for reconstructive surgical procedures especially for the repair of bone defects that do not regenerate spontaneously. The present study aimed to evaluate the effects of the elastin matrix (E24/50 and E96/37) incorporated with hydroxyapatite (HA) or morphogenetic protein (BMP) on the bone repair process in the distal metaphysis of rat femur. The groups were: control group (CG), hydrolyzed elastin matrix at 50°C/24h (E24/50), E24/50 + HA (E24/50/HA), E24/50 + BMP (E24/50/BMP), hydrolyzed elastin matrix at 37°C/96h (E96/37), E96/37 + HA (E96/37/HA), E96/37 + BMP (E96/37/BMP). Macroscopic and radiographic analyses showed longitudinal integrity of the femur in all groups without fractures or bone deformities. Microtomographically, all groups demonstrated partial closure by mineralized tissue except for the E96/37/HA group with hyperdense thin bridge formation interconnecting the edges of the ruptured cortical. Histologically, there was no complete cortical recovery in any group, but partial closure with trabecular bone. In defects filled with biomaterials, no chronic inflammatory response or foreign body type was observed. The mean volume of new bone formed was statistically significant higher in the E96/37/HA and E24/50 groups (71.28 ± 4.26 and 66.40 ± 3.69, respectively) than all the others. In the confocal analysis, it was observed that all groups presented new bone markings formed during the experimental period, being less evident in the CG group. Von Kossa staining revealed intense calcium deposits distributed in all groups. Qualitative analysis of collagen fibers under polarized light showed a predominance of red-orange birefringence in the newly regenerated bone with no difference between groups. It was concluded that the E24/50 and E96/37/HA groups promoted, with greater speed, the bone repair process in the distal metaphysis of rat femur.

Photobiomodulation Therapy Associated with Heterologous Fibrin Biopolymer and Bovine Bone Matrix Helps to Reconstruct Long Bones

Bone defects cause aesthetic and functional changes that affect the social, economic and especially the emotional life of human beings. This complication stimulates the scientific community to investigate strategies aimed at improving bone reconstruction processes using complementary therapies. Photobiomodulation therapy (PBMT) and the use of new biomaterials, including heterologous fibrin biopolymer (HFB), are included in this challenge. The objective of the present study was to evaluate the influence of photobiomodulation therapy on bone tibial reconstruction of rats with biomaterial consisting of lyophilized bovine bone matrix (BM) associated or not with heterologous fibrin biopolymer. Thirty male rats were randomly separated into three groups of 10 animals. In all animals, after the anesthetic procedure, a noncritical tibial defect of 2 mm was performed. The groups received the following treatments: Group 1: BM + PBMT, Group 2: BM + HFB and Group 3: BM + HFB + PBMT. The animals from Groups 1 and 3 were submitted to PBMT in the immediate postoperative period and every 48 h until the day of euthanasia that occurred at 14 and 42 days. Analyses by computed microtomography (µCT) and histomorphometry showed statistical difference in the percentage of bone formation between Groups 3 (BM + HB + PBMT) and 2 (BM + HFB) (26.4% ± 1.03% and 20.0% ± 1.87%, respectively) at 14 days and at 42 days (38.2% ± 1.59% and 31.6% ± 1.33%, respectively), and at 42 days there was presence of bone with mature characteristics and organized connective tissue. The µCT demonstrated BM particles filling the defect and the deposition of new bone in the superficial region, especially in the ruptured cortical. It was concluded that the association of PBMT with HFB and BM has the potential to assist in the process of reconstructing bone defects in the tibia of rats.

Evaluation of the Use of an Inorganic Bone Matrix in the Repair of Bone Defects in Rats Submitted to Experimental Alcoholism

To assess the effects of chronic alcoholism on the repair of bone defects associated with xenograft. Forty male rats were distributed in: control group (CG, n = 20) and experimental group (EG, n = 20), which received 25% ethanol ad libitum after a period of adaptation. After 90 days of liquid diet, the rats were submitted to 5.0-mm bilateral craniotomy on the parietal bones, subdividing into groups: CCG (control group that received only water with liquid diet and the defect was filled with blood clot), BCG (control group that received only water with liquid diet and the defect was filled with biomaterial), CEG (alcoholic group that received only ethanol solution 25% v/v with liquid diet and the defect was filled with blood clot), and BEG (alcoholic group that received only ethanol solution 25% v/v with liquid diet and the defect was filled with biomaterial). In the analysis of body mass, the drunk animals presented the lowest averages in relation to non-drunk animals during the experimental period. Histomorphologically all groups presented bone formation restricted to the defect margins at 60 days, with bone islets adjacent to the BCG biomaterial particles. CEG showed significant difference compared to BEG only at 40 days (17.42 ± 2.78 vs. 9.59 ± 4.59, respectively). In the birefringence analysis, in early periods all groups showed red-orange birefringence turning greenish-yellow at the end of the experiment. The results provided that, regardless of clinical condition, i.e., alcoholic or non-alcoholic, in the final period of the experiment, the process of bone defect recomposition was similar with the use of xenograft or only clot.

Photobiomodulation Therapy (PBMT) Applied in Bone Reconstructive Surgery Using Bovine Bone Grafts: A Systematic Review

The use of low-level laser therapy (LLLT) with biomodulatory effects on biological tissues, currently called photobiomodulation therapy (PBMT), assists in healing and reduces inflammation. The application of biomaterials has emerged in bone reconstructive surgery, especially the use of bovine bone due to its biocompatibility. Due to the many benefits related to the use of PBMT and bovine bones, the aim of this research was to review the literature to verify the relationship between PBMT and the application of bovine bone in bone reconstruction surgeries. We chose the PubMed/MEDLINE, Web of Science, and Scopus databases for the search by matching the keywords: "Bovine bone AND low-level laser therapy", "Bovine bone AND photobiomodulation therapy", "Xenograft AND low-level laser therapy", and "Xenograft AND photobiomodulation therapy". The initial search of the three databases retrieved 240 articles, 18 of which met all inclusion criteria. In the studies concerning animals (17 in total), there was evidence of PBMT assisting in biomaterial-related conduction, formation of new bone, bone healing, immunomarker expression, increasing collagen fibers, and local inflammation reduction. However, the results disagreed with regard to the resorption of biomaterial particles. The only human study showed that PBMT with bovine bone was effective for periodontal regeneration. It was concluded that PBMT assists the process in bone reconstruction when associated with bovine bone, despite divergences between applied protocols.

Unique heterologous fibrin biopolymer with hemostatic, adhesive, sealant, scaffold and drug delivery properties: a systematic review

Fibrin biopolymers, previously referred as "fibrin glue" or "fibrin sealants", are natural biomaterials with diverse applications on health. They have hemostatic, adhesive, sealant, scaffold and drug delivery properties and have become widely used in medical and dental procedures. Historically, these biomaterials are produced from human fibrinogen and human or animal thrombin, and the possibility of transmission of infectious diseases by human blood is not ruled out. In the 1990s, to overcome this problem, a new heterologous biomaterial composed of a thrombin-like enzyme purified from Crotalus durissus terrificus venom and a cryoprecipitate rich in fibrinogen extracted from buffaloes Bubalus bubalis blood has been proposed. Therefore, a systematic review of studies on exclusively heterologous fibrin sealants published between 1989 and 2018 was carried out using the following databases: PubMed, SciELO and Google Scholar. The keyword used was "heterologous fibrin sealant". The search resulted in 35 scientific papers in PubMed, four in SciELO and 674 in Google Scholar. After applying the inclusion/exclusion criteria and complete reading of the articles, 30 studies were selected, which formed the basis of this systematic review. It has been observed that the only completely heterologous sealant is the one produced by CEVAP/UNESP. This heterologous biopolymer is proven effective by several studies published in refereed scientific journals. In addition, clinical trials phase I/II for the treatment of chronic venous ulcers authorized by the Brazilian Health Regulatory Agency (ANVISA) were completed. Preliminary results have indicated a safe and promising effective product. Phase III clinical trials will be proposed and required to validate these preliminary findings.

Suitability of the use of an elastin matrix combined with bone morphogenetic protein for the repair of cranial defects

The use of biomaterials in medical and dental areas has become increasingly important due to the need to restore areas with bone loss or defects. This study analyzed the use of a new elastin polymer matrix combined with Bone Morphogenetic Protein for the repair of cranial defects in rats. Thirty rats were divided into five groups: control (C) defect without graft, E24 (defect filled with elastin matrix submitted to alkaline hydrolysis at 50°C for 24 h), E24/BMP (defect filled with elastin matrix treated at 50°C for 24 h plus BMP), E96 (defect filled with elastin matrix treated at 37°C for 96 h) and E96/BMP (defect filled with elastin matrix treated at 37°C for 96 h plus BMP). The animals were killed after 6 weeks. In the histological and microtomographic analysis, all groups showed bone growth from the defect margins remaining in this region without a marked inflammatory process, but in the E96/BMP group the lamellae were thicker and the collagen fibers more organized. Histometrically, the same group presented higher percentage of new formation (43.25 ± 3.72) in relation to the other groups. It was concluded that the support and delivery system formed by the elastin matrix associated with BMPs had a positive effect on the bone repair process.