Bone marrow aspirate combined with low-level laser therapy: A new therapeutic approach to enhance bone healing

Carbon fiber felt scaffold from Brazilian textile PAN fiber for regeneration of critical size bone defects in rats: A histomorphometric and microCT study

The objective of the present study was to evaluate the carbon fiber obtained from textile PAN fiber, in its different forms, as a potential scaffolds synthetic bone. Thirty-four adult rats were used (Rattus norvegicus, albinus variation), two critical sized bone defects were made that were 5 mm in diameter. Twenty-four animals were randomly divided into four groups: control (C)-bone defect + blood clot, non-activated carbon fiber felt (NACFF)-bone defect + NACFF, activated carbon fiber felt (ACFF)-bone defect + ACFF, and silver activated carbon fiber felt (Ag-ACFF)-bone defect + Ag-ACFF, and was observed by 15 and 60 days for histomorphometric, three-dimensional computerized microtomography (microCT) and mineral apposition analysis. On histomorphometric and microCT analyses, NACFF were associated with higher proportion of neoformed bone and maintenance of bone structure. On fluorochrome bone label, there was no differences between the groups. NACFF has shown to be a promising synthetic material as a scaffold for bone regeneration.

Hydrogel loaded with thiolated chitosan modified taxifolin liposome promotes osteoblast proliferation and regulates Wnt signaling pathway to repair rat skull defects

To alleviate skull defects and enhance the biological activity of taxifolin, this study utilized the thin-film dispersion method to prepare paclitaxel liposomes (TL). Thiolated chitosan (CSSH)-modified TL (CTL) was synthesized through charge interactions. Injectable hydrogels (BLG) were then prepared as hydrogel scaffolds loaded with TAX (TG), TL (TLG), and CTL (CTLG) using a Schiff base reaction involving oxidized dextran and carboxymethyl chitosan. The study investigated the bone reparative properties of CTLG through molecular docking, western blot techniques, and transcriptome analysis. The particle sizes of CTL were measured at 248.90 ± 14.03 nm, respectively, with zeta potentials of +36.68 ± 5.43 mV, respectively. CTLG showed excellent antioxidant capacity in vitro. It also has a good inhibitory effect on Escherichia coli and Staphylococcus aureus, with inhibition rates of 93.88 ± 1.59 % and 88.56 ± 2.83 % respectively. The results of 5-ethynyl-2 '-deoxyuridine staining, alkaline phosphatase staining and alizarin red staining showed that CTLG also had the potential to promote the proliferation and differentiation of mouse embryonic osteoblasts (MC3T3-E1). The study revealed that CTLG enhances the expression of osteogenic proteins by regulating the Wnt signaling pathway, shedding light on the potential application of TAX and bone regeneration mechanisms.

Low intensity near-infrared light promotes bone regeneration via circadian clock protein cryptochrome 1

Bone regeneration remains a great clinical challenge. Low intensity near-infrared (NIR) light showed strong potential to promote tissue regeneration, offering a promising strategy for bone defect regeneration. However, the effect and underlying mechanism of NIR on bone regeneration remain unclear. We demonstrated that bone regeneration in the rat skull defect model was significantly accelerated with low-intensity NIR stimulation. In vitro studies showed that NIR stimulation could promote the osteoblast differentiation in bone mesenchymal stem cells (BMSCs) and MC3T3-E1 cells, which was associated with increased ubiquitination of the core circadian clock protein Cryptochrome 1 (CRY1) in the nucleus. We found that the reduction of CRY1 induced by NIR light activated the bone morphogenetic protein (BMP) signaling pathways, promoting SMAD1/5/9 phosphorylation and increasing the expression levels of Runx2 and Osterix. NIR light treatment may act through sodium voltage-gated channel Scn4a, which may be a potential responder of NIR light to accelerate bone regeneration. Together, these findings suggest that low-intensity NIR light may promote in situ bone regeneration in a CRY1-dependent manner, providing a novel, efficient and non-invasive strategy to promote bone regeneration for clinical bone defects.

Impact of Oral Mesenchymal Stem Cells Applications as a Promising Therapeutic Target in the Therapy of Periodontal Disease

Periodontal disease is a chronic inflammatory condition affecting about 20–50% of people, worldwide, and manifesting clinically through the detection of gingival inflammation, clinical attachment loss, radiographically assessed resorption of alveolar bone, gingival bleeding upon probing, teeth mobility and their potential loss at advanced stages. It is characterized by a multifactorial etiology, including an imbalance of the oral microbiota, mechanical stress and systemic diseases such as diabetes mellitus. The current standard treatments for periodontitis include eliminating the microbial pathogens and applying biomaterials to treat the bone defects. However, periodontal tissue regeneration via a process consistent with the natural tissue formation process has not yet been achieved. Developmental biology studies state that periodontal tissue is composed of neural crest-derived ectomesenchyme. The aim of this review is to discuss the clinical utility of stem cells in periodontal regeneration by reviewing the relevant literature that assesses the periodontal-regenerative potential of stem cells.

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.

Effect of Photobiomodulation Therapy Associated With Biphasic Phosphate Calcium on Bone Repair: A Histomorphometric Study in Rats

Introduction: This study aimed to investigate the effects of photobiomodulation (PBM) therapy associated with biphasic calcium phosphate on calvaria critical defects in rats. Methods: Forty-eight (90 days old) adult male rats (Rattus norvegicus, Albinus variation, Wistar) received critical defects of 5 mm in diameter, which were made on their skull, and they were randomly assigned into the following groups: C-blood clot, B-biphasic calcium phosphate, L-photobiomodulation therapy, and B + L-biphasic calcium phosphate + photobiomodulation therapy. A low-level a gallium aluminum arsenide (GaAlAs) laser was applied in a single dose during surgery, in a wavelength of 660 nm and total energy density of 45 J/cm². On 30^th and 60^th days, the animals from each group were euthanized. Histological and histomorphometric analyses were performed. Results:In 30 days, almost all specimens (C, L, B and B + L) showed bone neoformation areas in regions near the borders of the surgical defect. In 60 days, in many specimens (C, L, B, B + L), it was possible to see a narrow neoformed bone structure along almost the whole extension of the surgical defect, though it was thinner than the original calvary bone. Data were recorded as mean ± standard deviation, and after normality was tested, a suitable statistical test was applied (α = 5%). On day 60, there was a statistically significant difference when comparing the proportion of neoformation area between group L (0.52%±0.13) and group B+L (0.20%±0.08). Group L showed a difference compared with all the groups when we compared the remaining distance between the edges of neoformed bone (C×L, P=0.0431; B × L, P=0.0386; L×B+L, P=0.0352), demonstrating a great defect closure. Conclusion: Our findings suggest that although biphasic calcium phosphate exerts some osteogenic activity during bone repair, PBM therapy is not able to modulate this process.

Innovative Concepts and Recent Breakthrough for Engineered Graft and Constructs for Bone Regeneration: A Literature Systematic Review

BACKGROUND

For decades, regenerative medicine and dentistry have been improved with new therapies and innovative clinical protocols. The aim of the present investigation was to evaluate through a critical review the recent innovations in the field of bone regeneration with a focus on the healing potentials and clinical protocols of bone substitutes combined with engineered constructs, growth factors and photobiomodulation applications.

METHODS

A Boolean systematic search was conducted by PubMed/Medline, PubMed/Central, Web of Science and Google scholar databases according to the PRISMA guidelines.

RESULTS

After the initial screening, a total of 304 papers were considered eligible for the qualitative synthesis. The articles included were categorized according to the main topics: alloplastic bone substitutes, autologous teeth derived substitutes, xenografts, platelet-derived concentrates, laser therapy, microbiota and bone metabolism and mesenchymal cells construct.

CONCLUSIONS

The effectiveness of the present investigation showed that the use of biocompatible and bio-resorbable bone substitutes are related to the high-predictability of the bone regeneration protocols, while the oral microbiota and systemic health of the patient produce a clinical advantage for the long-term success of the regeneration procedures and implant-supported restorations. The use of growth factors is able to reduce the co-morbidity of the regenerative procedure ameliorating the post-operative healing phase. The LLLT is an adjuvant protocol to improve the soft and hard tissues response for bone regeneration treatment protocols.

Glass ionomer heated or not to identify bone defect created in rat calvaria

Abstract Introduction Some experimental models have been used to evaluate the use of biomaterials in bone regeneration. Among them are the critical size defects (CSD) created in rat calvaria. An experimental model has been described in the literature, in which “L” markings are performed on the margins of the bone defects in order to assist in the precise identification of these defects during laboratory processing and analysis of the results. In the proposed model, the “L” markings are filled with amalgam. Objective The purpose of the present study was to evaluate the amalgam replacement of an experimental bony defect model in rat calvaria by heated or unheated glass ionomer. Material and method 24 rats were used. A 5 mm CSD was created at each animal calvaria. Two “L” shaped markings were made 2 mm from the margins of the bone defect, filled with amalgam (Group AM), heated glass ionomer cement (Group GIh) or not (Group GI). The animals were euthanized 15 days postoperatively. The areas of the surgical defect and the L-shaped marking were histomorphometrically analyzed and the data were analyzed statistically (p <0.05). Result There were no significant clinical, histological or methodological differences among the experimental groups. Conclusion It can be concluded that GI can replace AM in the proposed experimental model and GI heating did not promote additional benefits.

Mesenchymal stem cells surpass the capacity of bone marrow aspirate concentrate for periodontal regeneration

Regenerative approaches using mesenchymal stem cells (MSCs) have been evaluated to promote the complete formation of all missing periodontal tissues, e.g., new cementum, bone, and functional periodontal ligaments. MSCs derived from bone marrow have been applied to bone and periodontal defects in several forms, including bone marrow aspirate concentrate (BMAC) and cultured and isolated bone marrow mesenchymal stem cells (BM-MSCs). This study aimed to evaluate the periodontal regeneration capacity of BMAC and cultured BM-MSCs in the wound healing of fenestration defects in rats. Methodology: BM-MSCs were obtained after bone marrow aspiration of the isogenic iliac crests of rats, followed by cultivation and isolation. Autogenous BMAC was collected and centrifuged immediately before surgery. In 36 rats, fenestration defects were created and treated with suspended BM-MSCs, BMAC or left to spontaneously heal (control) (N=6). Their regenerative potential was assessed by microcomputed tomography (µCT) and histomorphometry, as well as their cell phenotype and functionality by the Luminex assay at 15 and 30 postoperative days. Results: BMAC achieved higher bone volume in 30 days than spontaneous healing (p<0.0001) by enhancing osteoblastic lineage commitment maturation, with higher levels of osteopontin (p=0.0013). Defects filled with cultured BM-MSCs achieved higher mature bone formation in early stages than spontaneous healing and BMAC (p=0.0241 and p=0.0143, respectively). Moreover, significantly more cementum-like tissue formation (p<0.0001) was observed with new insertion of fibers in specimens treated with BM-MSCs within 30 days. Conclusion: Both forms of cell transport, BMAC and BM-MSCs, promoted bone formation. However, early bone formation and maturation were achieved when cultured BM-MSCs were used. Likewise, only cultured BM-MSCs were capable of achieving complete periodontal regeneration with inserted fibers in the new cementum-like tissue.

Nanocomposites of Chitosan/Graphene Oxide/Titanium Dioxide Nanoparticles/Blackberry Waste Extract as Potential Bone Substitutes

New technologies based on nanocomposites of biopolymers and nanoparticles inspired by the nature of bone structure have accelerated their application in regenerative medicine, thanks to the introduction of reinforcing properties. Our research incorporated chitosan (CS) covalently crosslinked with glutaraldehyde (GLA) beads with graphene oxide (GO) nanosheets, titanium dioxide nanoparticles (TiO₂), and blackberry processing waste extract (BBE) and evaluated them as partial bone substitutes. Skullbone defects in biomodels filled with the scaffolds showed evidence through light microscopy, scanning electron microscopy, histological studies, soft tissue development with hair recovery, and absence of necrotic areas or aggressive infectious response of the immune system after 90 days of implantation. More interestingly, newly formed bone was evidenced by elemental analysis and Masson trichromacy analysis, which demonstrated a possible osteoinductive effect from the beads using the critical size defect experimental design in the biomodels. The results of this research are auspicious for the development of bone substitutes and evidence that the technologies for tissue regeneration, including chitosan nanocomposites, are beneficial for the adhesion and proliferation of bone cells.

Comparison of Single and Multiple Low-Level Laser Applications After Rapid Palatal Expansion on Bone Regeneration in Rats

Introduction: This study was performed to compare the effects of single and multiple irradiations of low-level laser therapy (LLLT) on bone regeneration in a mid-palatal suture following rapid palatal expansion (RPE). Methods: In this animal study, 40 male Wistar rats underwent RPE for 7 days and were divided into 4 groups including A: single LLLT on day 7, B: Multiple LLLT on days 7, 9, 11, 13 and 15, C: control (no LLLT), and D: sacrificed on day 7. Animals in group D were used to determine the amount of suture expansion. LLLT was done by a diode laser set at an 808 nm wavelength with a useful power output of 100 mW and duration of 0.1 ms. LLLT was applied to three points. After three weeks of retention, the rats were sacrificed and beheaded and the maxilla was evaluated by occlusal radiography, µ-CT, and histomorphometric analyses. A comparison of the mean measurements between the groups was performed using ANOVA and the Tukey post hoc test. Results: Based on occlusal radiography and µCT, bone density in group B was significantly higher than group A and group C (P<0.05). There was no significant difference in bone density between group A and group C (P>0.05). Mean suture width (MSW) in group B was significantly lesser than the control group (P=0.027) while there was no significant difference between MSWnin groups A and B (P=0.116) and groups A and C (P=0.317). Conclusion: It may be concluded that multiple low-power laser irradiation improves bone regeneration after RPE while single irradiation does not have a positive effect.

Biomimetic Hydrogels Loaded with Nanofibers Mediate Sustained Release of pDNA and Promote In Situ Bone Regeneration

Polymer hydrogels are generally insufficient biomechanics, strong resistance to cell adhesion, and weak bioactivity which limits their application in bone tissue engineering considerably. In order to develop a bone tissue engineering material with both good mechanical properties, osteogenic and angiogenic activity. Nanofibers carrying DNA plasmid (pNF) are introduced to gelatin methacryloyl (GelMA) and thiolated chitosan (TCS) system for preparing a novel GelMA/TCS/pNF composite hydrogel with dual network structure. By characterization of the compressive measurements, the resulting composite scaffold shows greatly enhanced mechanical strength (0.53 MPa) and is not damaged after 20 cycles of compression. And the fabricated composite scaffold displays sustained release of bone morphogenetic protein-2 that can induce osteogenic differentiation and angiopoietin-1 that promotes vascularization. The cell experiment shows that this system can significantly promote MC3T3-E1 cell attachment, proliferation, as well as osteogenic-related and angiogenic-related genes expression of MC3T3-E1 cells. Moreover, the in vivo results show that the composite scaffold with activated gene fibers can significantly promote osteogenesis and vascularization leading to favorable capacity of bone regeneration, meaning that the resulting biomimetic composite hydrogel scaffolds are excellent candidates for bone repair materials.

Bone repair assessment of critical size defects in rats treated with mineralized bovine bone (Bio-Oss®) and photobiomodulation therapy: a histomorphometric and immunohistochemical study

This study aimed to investigate the effects of administering photobiomodulation therapy (PBM) with bovine bone matrix on critical size defects in rats. Seventy-two adult male rats (albinus, Wistar), 90 days old, were used. Defect of 5 mm in diameter was made in their calvaria. The animals were divided into 4 groups: C-blood clot, B-Bio-Oss®, L-PBM, B+L-Bio-Oss®+PBM. Each group has been subdivided into 07, 30, and 60 days of observation. For PBM, a low GaAlAs energy of 660 nm was irradiated, total energy density of 45 J/cm² . PBM was conducted in a trans-surgical form once only. For immunohistochemistry, a semi-quantitative analysis was made of expression of osteoprotegerin (OPG), nuclear kappa B-factor ligand receptor activator (RANKL), and tartrate-resistant acid phosphatase (TRAP). All histomorphometric data were statistically analyzed by ANOVA and Tukey test, significance level of 5%. The groups that showed the highest proportion of neoformation were L (0.39% ± 0.13) and C (0.37% ± 0.97), but groups B and B+L had larger defect size (C-1.75 mm² ± 0.40, B-3.02 mm² ± 0.63, L-2.45 mm² ± 0.53, B+L-3.23 mm² ± 1.01). In immunohistochemistry, groups B and B+L had higher immunostaining scores for OPG and RANKL at 60 days, and TRAP immunostaining increased in all groups at 30 days, but group L was the only one to present specimens with score 0. Although, at 60 days, groups L and C presented the highest proportion of bone neoformation, at 30 days group B+L had more than twice as much bone neoformation as group B, the choice of treatment application should depend on the aim of the treatment.

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.

Bone marrow aspirate clot: A feasible orthobiologic

Musculoskeletal disorders are one of the major health burdens and a leading source of disability worldwide, affecting both juvenile and elderly populations either as a consequence of ageing or extrinsic factors such as physical injuries. This condition often involves a group of locomotor structures such as the bones, joints and muscles and may therefore cause significant economic and emotional impact. Some pharmacological and non-pharmacological treatments have been considered as potential solutions, however, these alternatives have provided quite limited efficacy due to the short-term effect on pain management and inability to restore damaged tissue. The emergence of novel therapeutic alternatives such as the application of orthobiologics, particularly bone marrow aspirate (BMA) clot, have bestowed medical experts with considerable optimism as evidenced by the significant results found in numerous studies addressed in this manuscript. Although other products have been proposed for the treatment of musculoskeletal injuries, the peculiar interest in BMA, fibrin clot and associated fibrinolytic mechanisms continues to expand. BMA is a rich source of various cellular and molecular components which have demonstrated positive effects on tissue regeneration in many in vitro and in vivo models of musculoskeletal injuries. In addition to being able to undergo self-renewal and differentiation, the hematopoietic and mesenchymal stem cells present in this orthobiologic elicit key immunomodulatory and paracrine roles in inflammatory responses in tissue injury and drive the coagulation cascade towards tissue repair via different mechanisms. Although promising, these complex regenerative mechanisms have not yet been fully elucidated.

Wound Healing and Cell Dynamics Including Mesenchymal and Dental Pulp Stem Cells Induced by Photobiomodulation Therapy: An Example of Socket-Preserving Effects after Tooth Extraction in Rats and a Literature Review

High-intensity laser therapy (HILT) and photobiomodulation therapy (PBMT) are two types of laser treatment. According to recent clinical reports, PBMT promotes wound healing after trauma or surgery. In addition, basic research has revealed that cell differentiation, proliferation, and activity and subsequent tissue activation and wound healing can be promoted. However, many points remain unclear regarding the mechanisms for wound healing induced by PBMT. Therefore, in this review, we present an example from our study of HILT and PBMT irradiation of tooth extraction wounds using two types of lasers with different characteristics (diode laser and carbon dioxide laser). Then, the effects of PBMT on the wound healing of bone tissues are reviewed from histological, biochemical, and cytological perspectives on the basis of our own study of the extraction socket as well as studies by other researchers. Furthermore, we consider the feasibility of treatment in which PBMT irradiation is applied to stem cells including dental pulp stem cells, the theme of this Special Issue, and we discuss research that has been reported on its effect.

Bone marrow coagulated and low-level laser therapy accelerate bone healing by enhancing angiogenesis, cell proliferation, osteoblast differentiation, and mineralization

The present study evaluated bone marrow aspirate (BMA) and low-level laser therapy (LLLT) on bone healing. It was created critical-size defects (CSD) of 5 mm diameter in rat calvaria of 64 rats. Animals were randomly divided into four groups: Control (blood clot), BMA (coagulated BMA), LLLT (laser irradiation and blood clot), and BMA/LLLT (laser irradiation and coagulated BMA). Euthanasia was performed at 15 or 30 days postoperative. Immunohistochemical reactions were performed to identify vascular endothelial growth factor (VEGF), proliferating cell nuclear antigen (PCNA), runt-related transcription factor-2 (Runx2), bone morphogenetic protein-2 (BMP-2), osteocalcin (OCN), and osteopontin (OPN). The markers were quantified, and data were statistically analyzed. Groups BMA/LLLT and LLLT presented significantly higher VEGF expression than group control. Group BMA/LLLT presented a significantly higher expression of PCNA than all experimental groups. Groups BMA and BMA/LLLT presented significantly higher expression of BMP-2 than all experimental groups. Groups LLLT and BMA/LLLT presented significantly higher expression of OPN than groups control and BMA. Groups LLLT, BMA, and BMA/LLLT presented a significantly higher expression of OCN than group control. It can be concluded that the association of BMA and LLLT enhanced bone healing by improving expression of VEGF, PCNA, Runx2, BMP-2, OPN, and OCN.

Evidence from systematic reviews on photobiomodulation of human bone and stromal cells: Where do we stand?

This study summarizes the available evidence from systematic reviews on the in vitro effects of photobiomodulation on the proliferation and differentiation of human bone and stromal cells by appraising their methodological quality. Improvements for future studies are also highlighted, with particular emphasis on in vitro protocols and cell-related characteristics. Six reviews using explicit eligibility criteria and methods selected in order to minimize bias were included. There was no compelling evidence on the cellular mechanisms of action or treatment parameters of photobiomodulation; compliance with quality assessment was poor. A rigorous description of laser parameters (wavelength, power, beam spot size, power density, energy density, repetition rate, pulse duration or duty cycle, exposure duration, frequency of treatments, and total radiant energy), exposure conditions (methods to ensure a uniform irradiation and to avoid cross-irradiation, laser-cell culture surface distance, lid presence during irradiation) and cell-related characteristics (cell type or line, isolation and culture conditions, donor-related factors where applicable, tissue source, cell phenotype, cell density, number of cell passages in culture) should be included among eligibility criteria for study inclusion. These methodological improvements will maximize the contribution of in vitro studies on the effects of photobiomodulation on human bone and stromal cells to evidence-based translational research.

Effect of Low- Level Laser Therapy on Bone Regeneration of Critical-Size Bone Defects: A Systematic Review of In Vivo Studies and Meta-Analysis

OBJECTIVE

Low-level laser therapy is a method for osteogenesis since it stimulates cell proliferation, vascularization and osteoblastic activity. Various protocols applying low-level laser with different outcomes exist. The aim of the present study was to review the result of different methods on bone formation in critical-size defects of in vivo studies.

DESIGN

According to PRISMA statement, electronic search of PubMed, google scholar, Scopus and Web of Science and a hand search limited to in vivo English language studies until December 2019. Studies used low-level laser therapy in bone regeneration of critical-size defects met the inclusion criteria and which used high power lasers or a defect size smaller than 5 mm, were excluded.

RESULTS

Finally, 18 studies were included. Fourteen studies utilized low-level laser with a wavelength ranging from 606 to 980 nm and 53 % of studies applied low-level laser in a single session. Ten studies utilized continuous wave mode of laser. Highest and lowest values of power density were 1.5 W/cm² and 0.1 W/cm² in order. Eleven studies evaluated low-lever laser therapy on defects of 5 mm in calvaria. Meta-analysis showed the positive effect of low-level laser therapy on osteogenesis after 30 days compared to control group and no significant difference after 60 days.

CONCLUSIONS

New bone formation can be increased in early stage by applying low-level laser therapy through stimulating osteoblasts and fibroblasts' proliferation. This effect would be more remarkable by combining with bone substitutes. Hence, for each case, protocol selection should be performed according defect's properties, attentively.

Influence of electromagnetic waves, with maxima in the green or red range, on the morphofunctional properties of multipotent stem cells

This paper examines the effect of electromagnetic waves, with maxima in the green or red regions of the spectrum, on the morphofunctional state of multipotent mesenchymal stromal cells. The illumination regimes used in our experiments did not lead to any substantial heating of the samples; the physical parameters of the lighting were carefully monitored. When the samples were illuminated with a green light, no significant photostimulatory effect was observed. Red light, on the other hand, had an evident photostimulatory effect. It is shown that photostimulation with a red light decreases the enzymatic activities of mitochondrial dehydrogenases and enhances the viability of cells, their proliferative activity, and their ability to form bone tissue. It is also established that red light stimulates cell proliferation, while not activating the genes that increase the risk of the subsequent malignant transformation of cells or their death. This paper discusses the possible role of hydrogen peroxide in the processes examined.

Photobiomodulation therapy (PBMT) in bone repair: A systematic review

BACKGROUND

Photobiomodulation therapy (PBMT) using low-level laser influences the release of several growth factors involved in the formation of epithelial cells, fibroblasts, collagen and vascular proliferation, besides accelerating the synthesis of bone matrix due to the increased vascularization and lower inflammatory response, with significant increase of osteocytes in the irradiated bone. Considering its properties, beneficial effects and clinical relevance, the aim of this review was to analyze the scientific literature regarding the use of PBMT in the process of bone defect repair.

METHODS

Electronic search was carried out in PubMed/MEDLINE^Ⓡ and Web of Science databases with combination of the descriptors low-level laser therapy AND bone repair, considering the period of publication until the year 2018.

RESULTS

The literature search identified 254 references in PubMed/MEDLINE and 204 in Web of Science, of which 33 and 4 were selected, respectively, in accordance with the eligibility requirements. The analysis of researches showed articles using PBMT in several places of experimentation in the subjects, different types of associated biomaterials, stimulatory effects on cell proliferation, besides variations in the parameters of use of laser therapy, mainly in relation to the wavelength and density of energy. Only four articles reported that the laser did not improve the osteogenic properties of a biomaterial.

CONCLUSIONS

Many studies have shown that PBMT has positive photobiostimulatory effects on bone regeneration, accelerating its process regardless of parameters and the use of biomaterials. However, standardization of its use is still imperfect and should be better studied to allow correct application concerning the utilization protocols.

Autologous bone marrow clot as an alternative to autograft for bone defect healing

Objectives

Long bone defects often require surgical intervention for functional restoration. The ‘gold standard’ treatment is autologous bone graft (ABG), usually from the patient’s iliac crest. However, autograft is plagued by complications including limited supply, donor site morbidity, and the need for an additional surgery. Thus, alternative therapies are being actively investigated. Autologous bone marrow (BM) is considered as a candidate due to the presence of both endogenous reparative cells and growth factors. We aimed to compare the therapeutic potentials of autologous bone marrow aspirate (BMA) and ABG, which has not previously been done.

Methods

We compared the efficacy of coagulated autologous BMA and ABG for the repair of ulnar defects in New Zealand White rabbits. Segmental defects (14 mm) were filled with autologous clotted BM or morcellized autograft, and healing was assessed four and 12 weeks postoperatively. Harvested ulnas were subjected to radiological, micro-CT, histological, and mechanical analyses.

Results

Comparable results were obtained with autologous BMA clot and ABG, except for the quantification of new bone by micro-CT. Significantly more bone was found in the ABG-treated ulnar defects than in those treated with autologous BMA clot. This is possibly due to the remnants of necrotic autograft fragments that persisted within the healing defects at week 12 post-surgery.

Conclusion

As similar treatment outcomes were achieved by the two strategies, the preferred treatment would be one that is associated with a lower risk of complications. Hence, these results demonstrate that coagulated BMA can be considered as an alternative autogenous therapy for long bone healing.

Cite this article: Z. X. H. Lim, B. Rai, T. C. Tan, A. K. Ramruttun, J. H. Hui, V. Nurcombe, S. H. Teoh, S. M. Cool. Autologous bone marrow clot as an alternative to autograft for bone defect healing. Bone Joint Res 2019;8:107–117. DOI: 10.1302/2046-3758.83.BJR-2018-0096.R1.

Bone Healing Evaluation in Critical-Size Defects Treated With Xenogenous Bone Plus Porcine Collagen

PURPOSE

This study aimed to evaluate the osteoconductive features of Bio-Oss Collagen in large critical-size defects (8 mm).

MATERIALS AND METHODS

Thirty-six adult Wistar Albinus male adult rats were carried out a critical-size defect with a trephine bur of 8 mm in the calvaria. Groups were divided depending on the filling biomaterial as follows: group BO: Bio-Oss (n = 18); group BOC: Bio-Oss Collagen (n = 18). After 7, 30, and 60 days, 6 rats of each group were euthanized with anesthetic overdose. Specimens were laboratory processed for histomorphometric analysis. Histomorphometric data were statistically analyzed by analysis of variance and post-Tukey test (P < 0.05).

RESULTS

Statistical differences were found in new bone formation just in the intragroup comparison among periods after 7 and 60 postoperative days, indicating more new bone formation after 60 days (Tukey test, P = 0.029).

CONCLUSION

Under the limitation of this research, it could be concluded that Bio-Oss and Bio-Oss Collagen in this experimental model did not show osteoconductive features.

Comparison of effects of LLLT and LIPUS on fracture healing in animal models and patients: A systematic review

The aim of this paper is to study the in vivo potency of low-level laser therapy (LLLT) and low intensity pulsed ultrasound (LIPUS) alone, accompanied by bone grafts, or accompanied by other factors on fracture healing in animal models and patients. In this paper, we aim to systematically review the published scientific literature regarding the use of LLLT and LIPUS to accelerate fracture healing in animal models and patients. We searched the PubMed database for the terms LLLT or LIPUS and/or bone, and fracture. Our analysis also suggests that both LIPUS and LLLT may be beneficial to fracture healing in patients, and that LIPUS is more effective. These finding are of considerable importance in those treatments with a LIPUS, as a laser device may reduce healing time. The most clinically relevant impact of the LIPUS treatment could be a significant reduction in the proportion of patients who go on to develop a nonunion. If it is confirmed that the therapeutic influence is true and reliable, patients will obtain benefits from LIPUS and LLLT. Further clinical trials of high methodological quality are needed in order to determine the optimal role of LIPUS and LLLT in fracture healing in patients.

Stimulation of morphofunctional repair of the facial nerve with photobiomodulation, using the end-to-side technique or a new heterologous fibrin sealant

This research evaluated the influence of Photobiomodulation Therapy (PBMT) on lesions of the facial nerve repaired with the end-to-side technique or coaptation with a new heterologous fibrin sealant. Thirty-two Wistar rats were separated into 5 groups: Control group (CG), where the buccal branch of the facial nerve was collected; Experimental Suture Group (ESG) and Experimental Fibrin Group (EFG), in which the buccal branch was end-to-side sutured to the zygomatic branch on the right side of the face or coaptated with fibrin sealant on the left side; Experimental Suture Laser Group (ESLG) and Experimental Fibrin Laser Group (EFLG), in which the same procedures were performed as the ESG and EFG, associated with PBMT (wavelength of 830nm, energy density 6.2J/cm², power output 30mW, beam area of 0.116cm², power density 0.26W/cm², total energy per session 2.16J, cumulative dose of 34.56J). The laser was applied for 24s/site at 3 points on the skin's surface, for a total application time of 72s, performed immediately after surgery and 3 times a week for 5weeks. A statistically significant difference was observed in the fiber nerve area between the EFG and EFLG (57.49±3.13 and 62.52±3.56μm², respectively). For the area of the axon, fiber diameter, axon diameter, myelin sheath area and myelin sheath thickness no statistically significant differences were found (p<0.05). The functional recovery of whisker movement occurred faster in the ESLG and EFLG, which were associated with PBMT, with results closer to the CG. Therefore, PBMT accelerated morphological and functional nerve repair in both techniques.

Low level laser (LLL) attenuate LPS-induced inflammatory responses in mesenchymal stem cells via the suppression of NF-κB signaling pathway in vitro

Background

Considering promising results in animal models and patients, therapeutic use of MSCs for immune disease is likely to undergo continued evaluation. Low-lever laser (LLL) has been widely applied to retard the inflammatory reaction. LLL treatment can potentially be applied in anti-inflammatory therapy followed by stem cell therapy.

Aim of the study

The purpose of this study was to investigate the effect of LLL (660 nm) on the inflammatory reaction induced by LPS in human adipose derived mesenchymal stem cells (hADSCs) and pertinent mechanism.

Materials and methods

Anti-inflammatory activity of LLL was investigated by LPS-induced mesenchymal stem cells. The production and expression of pro-inflammatory cytokines were evaluated by ELISA kits and RT-qPCR. Nuclear translocation of NF-κB was indicated by immunofluorescent staining. Phosphorylation status of NF-κB p65 and IκBα were illustrated by western blot assay. ROS generation was measured with CM-H2DCFDA, and NO secretion was determined by DAF-FM. We studied surface expression of lymphocyte activation markers when Purified peripheral blood mononuclear cell (PBMC) were activated by phytohaemagglutinin (PHA) in the presence of 3 types of treated MSCs.

Results

LLL reduced the secretion of IL-1β, IL-6, IL8, ROS and NO in LPS treated MSCs. Immunofluorescent assay demonstrated the nuclear translocation decrease of NF-κB in LLL treated LPS induced MSCs. Western blot analysis also suggested that LLL suppressed NF-κB activation via regulating the phosphorylation of p65 and IκBα. MSC significantly reduced the expression of activation markers CD25 and CD69 on PHA-stimulated lymphocytes.

Conclusion

The results indicate that LLL suppressed the activation of NF-κB signaling pathway in LPS treated MSCs through inhibiting phosphorylation of p65 and IκBα, which results in good anti-inflammatory effect. In addition, LLL attenuated activation-associated markers CD25 and CD69 in co-cultures of PBMC and 3 types of treated MSCs.

Effects of low-level laser therapy on autogenous bone graft stabilized with a new heterologous fibrin sealant

Autogenous bone grafts are used to repair bone defects, and the stabilization is needed for bone regeneration. Laser photobiomodulation is a modality of treatment in clinical practice for tissue regeneration, and it has therapeutic effects as an anti-inflammatory, analgesic and modulating cellular activity. The aim of the present study was to evaluate the effects of low-level laser therapy (LLLT) on an autogenous bone graft integration process stabilized with a new heterologous fibrin sealant. Forty rats were divided into two groups: Autogenous Fibrin Graft (AFG, n=20), in which a 5mm dome osteotomy was conducted in the right parietal bone and the graft was adhered to the left side using fibrin sealant; and Autogenous Fibrin Graft Laser (AFGL, n=20), which was subjected to the same procedures as AFG with the addition of LLLT. The treatment was performed immediately following surgery and then three times a week until euthanasia, using an 830nm laser (30mW, 6J/cm(2), 0.116cm(2), 258.6mW/cm(2), 2.9J). Five animals from each group were euthanized at 10, 20, 30 and 40days postoperative, and the samples were submitted to histomorphological and histomorphometric analysis. Partial bone regeneration occurred, with new bone tissue integrating the graft to the recipient bed and small areas of connective tissue. Comparative analysis of the groups at the same intervals revealed minor interfaces in group AFGL, with statistically significant differences (p<0.05) at all of the analyzed intervals (10days p=0.0087, 20days p=0.0012, 30days p<0.0001, 40days p=0.0142). In conclusion, low-level laser therapy stimulated bone regeneration and accelerated the process of integration of autogenous bone grafts.

Effect of Diode Laser on Healing of Tooth Extraction Socket: An Experimental Study in Rabbits

OBJECTIVES

To evaluate the effect of low-level laser therapy on healing of extracted tooth socket of healthy rabbits.

DESIGN

The sample of this study was 20 male rabbits of 2-2.5 kg weight with age range of 8-12 months. Right and left lower first premolar teeth were extracted. The extraction sockets of lower right first premolar were irradiated with 0.9 W gallium-aluminum-arsenide (GaAlAs) diode laser for 5 min, immediately after extraction and then every 72 h for the next 12 days. The extraction socket of left side were not exposed to laser and served as a control. The animals were sacrificed after 7, 14, 30 and 45 days and the experimental and control sockets were removed from the harvested mandibles and prepared for haematoxylin and eosin staining and Masson's stain. The prepared slides were examined under light microscope for histological and histomorphometric examination.

RESULTS

The histological examination showed that diode laser-treated sockets demonstrated early formed new bone with faster maturation of primary bone to secondary bone as compared to non-treated control sockets. Histomorphometric analysis revealed a statistically significant increase in the density and volume of trabecular bone in laser-treated sockets than control sockets.

CONCLUSION

Diode laser application to tooth extraction socket has a positive effect on bone formation.

Low Reactive Level Laser Therapy for Mesenchymal Stromal Cells Therapies

Low reactive level laser therapy (LLLT) is mainly focused on the activation of intracellular or extracellular chromophore and the initiation of cellular signaling by using low power lasers. Over the past forty years, it was realized that the laser therapy had the potential to improve wound healing and reduce pain and inflammation. In recent years, the term LLLT has become widely recognized in the field of regenerative medicine. In this review, we will describe the mechanisms of action of LLLT at a cellular level and introduce the application to mesenchymal stem cells and mesenchymal stromal cells (MSCs) therapies. Finally, our recent research results that LLLT enhanced the MSCs differentiation to osteoblast will also be described.

[The application of stem cells, visible and infrared light in regenerative medicine. Part 1]

OBJECTIVE

The present article was designed to overview the experimental studies of visible and infrared light irradiation of human and animal stem cells (SC) in vitro and in vivo for the evaluation of its photobiomodulatory effects. The results will be used to elaborate substantiation for the choice of the parameters of SC light irradiation and to develop recommendations for the application of this method in regenerative medicine (RM).

BACKGROUND

The clinical application of light irradiation is a matter of contrsy, in the first place due to the difficulties encountered in the rational choice of irradiation parameters. The theoretical substantiation of such choice remains a stumbling block too despite the long history of photoghromotherapy. There is thus far no reliable theoretical basis for the adequate choice of such irradiation parameters as power density, radiation dose, and exposure time. The experiences with the light application for the purpose of regenerative medicine have never been summarized.

RESULTS

The present review encompasses 78 articles selected for the basic analysis that report the studies with the use of a variety of SC types. The analysis has demonstrated that clinical investigations into the influence of light on the stem cells are still in their infancy. It was shown that the irradiation parameters need to be chosen taking into consideration the type of the stem cells. Different authors report the achievement of the maximum SC proliferation and differentiation rates at energy densities as high as 50 mW/sq.cm, small radiation doses (around 1 J/sq.cm) and exposure time (on the order of seconds).

CONCLUSION

The general conclusion for Parts 1 and II of this communication will be presented in the next issue of this journal (number 2, 2015).

Effects of caffeic acid phenethyl ester on wound healing in calvarial defects

OBJECTIVE

The aim of this study is to analyze histologically the effect of CAPE on bone healing of Critical Size Defect (CSD) in rat calvaria.

STUDY DESIGN

Thirty-two 3-month-old male rats were used. The animals were randomly divided into four groups. Group A received isotonic saline solution, Group B received CAPE (50 mmol/kg) locally, Group C received CAPE (100 mmol/kg) locally and Group D received CAPE (10 mmol/kg/day i.p. for 28 days) systematically. A 5-mm diameter calvarial defect was created in the right side of the parietal bone without damaging the underlying dura mater. Twenty-eight days after the surgery, all the animals were sacrificed. The original defect area was removed from the animal's calvarium bone en bloc. Beginning at the center of the surgical defect, serial sections of 6 µm thick were cut longitudinally. The sections were stained with hematoxylin and eosin for analysis under a light microscope. The sections were analyzed for the presence of inflammatory infiltrate, connective tissue formation and new bone formation. Computer-assisted histomorphometic measurements were carried out with an automated image analysis system.

RESULTS

The total new bone areas were significantly greater in group D than in all groups and group C was statistically insignificant from the other groups (p < 0.05). Group B had a greater, but not statistically significant (p > 0.05), amount of total regenerated bone area than the control group.

CONCLUSION

The results indicate that 100 mmol/kg topical and 10 mmol/kg/day systemic application of CAPE increases bone healing, especially with systemic application.