Autologous Periosteum-Derived Micrografts and PLGA/HA Enhance the Bone Formation in Sinus Lift Augmentation

Use of autologous micrografts associated with xenogeneic anorganic bone in vertical bone augmentation procedures with Barbell Technique®

INTRODUCTION

Bidirectional vertical ridge augmentation in the posterior maxilla is very challenging.

PURPOSE

To evaluate the regenerative potential of micrografts, derived from periosteum or bone tissue, added to an anorganic xenograft in vertical reconstruction of the posterior maxilla, by a prospective, controlled study.

MATERIALS AND METHODS

After clinical selection and the analysis of CBCT scans, 24 posterior maxillary sites, in 19 patients, were treated by using Barbell Technique®. Sites requiring both inlay and onlay reconstruction were enrolled in the study. In the Control Group (CG, n = 8), a xenograft was used in the inlay site and for the onlay site, a 1:1 mix of xenograft and an autograft was used. In Test Group 1 (TG1, n = 8), both inlay and onlay sites were grafted with the xenograft associated with the micrografts derived from periosteum. In Test Group 2 (TG2, n = 8), both inlay and onlay sites were grafted with the xenograft associated with the micrografts derived from bone. Six months after the procedures, CBCT scans were obtained, and bone biopsy samples were harvested during implant placement surgery. The bone specimens were analyzed histomorphometrically, by measuring the percentages of vital mineralized tissue (VMT), non vital mineralized tissue (NVMT) and non mineralized tissue (NMT). Immunohistochemically, the levels of VEGF were categorized by a score approach.

RESULTS

Histomorphometric analysis revealed, for the inlay grafts, no significant difference among the groups for VMT, NVMT and NMT. However, for onlay grafts, CG achieved a higher amount of VMT in comparison with TG2, and the opposite occurred for NMT values. In this regard, no statistical difference was observed between CG and TG1. Concerning immunohistochemistry, the VEGF values for CG and TG1 were slightly higher than those obtained by TG2 for both inlay and onlay grafts, but without statistical significance. CBCT analysis showed a similar level of gain for all groups, for both inlay and onlay bone augmentation sites. Clinically, one implant (in CG) within a total of 50 implants installed, had early failure and was replaced after 3 months. All patients received implant supported prosthesis.

CONCLUSION

This study indicated that the clinical use of micrograft derived from periosteum may have some potential to increase bone formation in onlay reconstructions, unlike the micrograft derived from bone tissue.

Efficacy of autologous micrografts technology: a promising approach for chronic wound healing and tissue regeneration-a pilot study

Introduction

This study explores the efficacy of Autologous Micrografts Technology (AMG) in treating chronic wounds refractory to traditional therapies.

Methods

AMGs, derived from adipose tissue or dermis using a mechanical fragmentation process, were applied to patients with post-surgical dehiscence. A comprehensive evaluation of wound healing outcomes, including surface area reduction and complete healing, was conducted over a 90-day follow-up period. Additionally, the study investigated the cellular antioxidant activity of AMG solutions and characterized the exosomes obtained through mechanical disaggregation.

Results

Results indicate significant improvements (p < 0.05) in wound healing, with 91.66% of patients showing at least a 50% reduction in lesion size and 75% achieving complete healing by day 90. Notably, AMG technology demonstrated immediate efficacy with fat-only application, while combined dermis and fat micrografts showed longer-term benefits, particularly in chronic wounds. The study also elucidated the mechanism of action of AMGs, highlighting their role in enhancing cellular antioxidant activity and exosome-mediated tissue regeneration.

Discussion

Overall, these findings underscore the promising potential of AMG technology as a versatile and effective treatment option for chronic wounds, warranting further investigation into its mechanisms and clinical applications.

An easy-to-use semi-automatic volumetric evaluation for secondary bone grafting in patients with unilateral alveolar cleft

Surgical intervention for alveolar bone formation is important in patients with alveolar cleft; however, the treatment methods and materials are still controversial. A precise evaluation method for postoperative bone formation is important for comparing outcomes and establishing the best treatment protocol. The purpose of this study is to establish a new method of evaluating surgical outcomes for patients with alveolar cleft. Computed tomography datasets from 20 patients who underwent secondary alveolar bone grafting were obtained before and 1 year after surgery. Six anatomical landmarks were used to superimpose the preoperative and mirrored preoperative volume and postoperative volume data. The cleft region was segmented by subtracting the preoperative from mirrored preoperative volume data, and the failed osteogenesis region was segmented by subtracting the postoperative volume data from the cleft region; subsequently, the bone formation ratio was calculated. Two observers performed this method using a free software 3D slicer and the average evaluation times were 12.7 and 13.2 min for observers 1 and 2, respectively. Method reliability was determined by evaluating intraclass correlation coefficients. The intra-observer intraclass correlation coefficients were 0.97 and 0.96 for observers 1 and 2, respectively. The inter-observer intraclass correlation coefficient was 0.97. Our method is practical for assessing bone formation after treatment, which does not require specific knowledge or software and can be used by ordinary physicians.

In Vitro Characterization of Canine Microfragmented Adipose Tissue Non-Enzymatically Extracted from the Thigh and Lumbar Regions

Simple Summary

Mesenchymal stem cells are located in bone marrow, adipose tissue, synovial membrane, and muscular tissue. They have an immunosuppressive, anti-inflammatory, and antifibrotic effect. Tissue engineering considers the usage of mesenchymal stem cells as a possible option for regenerating tissues, with respect to bone and cartilage, due to their ability to differentiate into multiple cytotypes (including chondrocytes and osteoblasts). Herein, we characterize a non-invasive solution based on Rigenera^® technology, a mechanical disaggregation method able to produce autologous adipose tissue-derived micrografts which are analogous to adipose-derived stem cells.

Abstract

Within the adult canine population, disabilities and symptoms including joint pain and functional impairment are commonly observed in articular cartilage lesions and present a challenging feat in the operating room. Clinical settings require less invasive and more minimally manipulated measures facilitated by innovative and advanced technology. Mesenchymal stem cells have recently been proposed and, furthermore, autologous adipose tissue administration via injection has emerged as a new albeit somewhat controversial therapeutic tool. The purpose of this study is to characterize canine autologous micro-fragmented adipose tissue (micrografts) by mechanical approach without substantial manipulations. Adipose tissue samples collected from six dogs were processed by a Rigenera device and by enzymatic digestion from two different body regions (lumbar and thigh region). Interestingly, the immunophenotypic analysis attested that cells from Rigenera^® were highly positive for the mesenchymal stem cells markers CD73 and CD90, less positive for hematopoietic CD45 and CD34, and negative for MHC class II antibodies (which play a role in immune responses). Finally, the Rigenera^® technology obtained micrografts with a 35% higher expression of the IL10 gene with relevant anti-inflammatory activities compared to the enzymatic digestion protocol. This evidence suggests a potential improved clinical outcome capable of modulating inflammation and immune responses.

Comparison of two different biomaterials in the bone regeneration (15, 30 and 60 days) of critical defects in rats

PURPOSE

To evaluate and compare two types of different scaffolds in critical bone defects in rats.

METHODS

Seventy male Wistar rats (280 ± 20 grams) divided into three groups: control group (CG), untreated animals; biomaterial group 1 (BG1), animals that received the scaffold implanted hydroxyapatite (HA)/poly(lactic-co-glycolic) acid (PLGA); and biomaterial group 2 (BG2), animals that received the scaffolds HA/PLGA/Bleed. The critical bone defect was induced in the medial region of the skull calotte with the aid of an 8-mm-diameter trephine drill. The biomaterial was implanted in the form of 1.5 mm thick scaffolds, and samples were collected after 15, 30 and 60 days. Non-parametric Mann-Whitney test was used, with the significance level of 5% (p ≤ 0.05).

RESULTS

Histology revealed morphological and structural differences of the neoformed tissue between the experimental groups. Collagen-1 (Col-1) findings are consistent with the histological ones, in which BG2 presented the highest amount of fibers in its tissue matrix in all evaluated periods. In contrast, the results of receptor activator of nuclear factor kappa-Β ligand (Rank-L) immunoexpression were higher in BG2 in the periods of 30 and 60 days, indicating an increase of the degradation of the biomaterial and the remodeling activity of the bone.

CONCLUSIONS

The properties of the HA/PLGA/Bleed scaffold were superior when compared to the scaffold composed only by HA/PLGA.

Tissue regeneration: an overview from stem cells to micrografts

Regenerative medicine represents a major challenge for the scientific community. The choice of the biological sources used, such as stem cells and grafts, is crucial. Stem cell therapy is mainly related to the use of mesenchymal stem cells; however, clinical trials are still needed to investigate their safety. The micrografting technique was conceived by Cicero Parker Meek in 1958. It is based on the principle that by increasing the superficial area of skin grafts and reducing the size of its particles, it is possible to cover an area larger than the original donor site. Stem cells are pluripotent cells that have the capacity to differentiate into all cell types and are self-renewing, whereas micrografts derive from a small fragment of an autologous tissue and exhibit limited differentiative potential compared with stem cells. Therefore, stem cells and micrografts cannot be considered equivalent, although in some cases they exhibit similar regenerative potential, which is the focus of this review. Last, stem cell therapies remain limited because of complex and costly processes, making them not very feasible in clinical practice, whereas obtaining micrografts is generally a one-step procedure that does not require any advanced tissue manipulation.

Advanced Biomaterials and Techniques for Oral Tissue Engineering and Regeneration-A Review

The reconstruction or repair of oral and maxillofacial functionalities and aesthetics is a priority for patients affected by tooth loss, congenital defects, trauma deformities, or various dental diseases. Therefore, in dental medicine, tissue reconstruction represents a major interest in oral and maxillofacial surgery, periodontics, orthodontics, endodontics, and even daily clinical practice. The current clinical approaches involve a vast array of techniques ranging from the traditional use of tissue grafts to the most innovative regenerative procedures, such as tissue engineering. In recent decades, a wide range of both artificial and natural biomaterials and scaffolds, genes, stem cells isolated from the mouth area (dental follicle, deciduous teeth, periodontal ligament, dental pulp, salivary glands, and adipose tissue), and various growth factors have been tested in tissue engineering approaches in dentistry, with many being proven successful. However, to fully eliminate the problems of traditional bone and tissue reconstruction in dentistry, continuous research is needed. Based on a recent literature review, this paper creates a picture of current innovative strategies applying dental stem cells for tissue regeneration in different dental fields and maxillofacial surgery, and offers detailed information regarding the available scientific data and practical applications.

Evaluation of Bone Regeneration in Rat Calvaria Using Bone Autologous Micrografts and Xenografts: Histological and Histomorphometric Analysis

The aim of this study was to investigate the effect of the use of autologous micrografts obtained by the Rigenera® Micrografting Technology and xenograft on critical size defects created in the calvaria of rats. Forty-eight rats were randomly divided into four groups for each of the two evaluation times (15 and 30 days) (n = 6). After general anesthesia, a 5-mm diameter bone defect was created in the calvaria of each animal. Each defect was filled with the following materials: blood clot, autologous bone graft, xenograft, and xenograft associated with autologous micrografts. Histomorphometric and histological analysis showed that the group that have received the Rigenera® processed autologous micrografts combined with the xenograft and the group that received autologous bone graft resulted in greater bone formation in both time points when compared with the use of the xenograft alone and blood clot.

Effects of autologous micrografts on stable bilateral vitiligo: A focus on hand lesions

Vitiligo is an autoimmune skin disorder characterized by depigmented patches of the skin associated with, among several factors, dysregulation and death of melanocytes. Currently, the treatment of vitiligo is based both on the arrest of the progression of active disease and on the stimulation of the skin repigmentation. The aim of this study was to assess the effects of autologous micrografts and narrowband ultraviolet B (NBUVB) phototherapy for skin repigmentation of patients with bilateral stable vitiligo. Autologous micrografts are derived from mechanical disaggregation of small pieces of the patient's own skin, while phototherapy is a strategy treatment already used. Twenty patients with stable bilateral vitiligo were treated, showing a mean percentage rate of 59.1% at baseline. Combined treatment by autologous micrografts and NBUVB was performed only on the lesions of the hands, and the clinical follow up was performed after 3 and 6 months by photographs taken under Wood's light. After 6 months, we classed 100% of patients as responders. We also reported a mean of repigmentation rate of 36.7% after 3 months and 64.6% after 6 months of treatment. In particular, six of the 20 patients reached a marked repigmentation rate (75-100%), four moderate (51-75%) and 10 mild (26-50%). No adverse effects were observed and no drugs were administrated as co-adjuvant therapy. These results are suggestive of a potential wide use of autologous micrografts associated with NBUVB phototherapy for the treatment of stable vitiligo.

Autologous grafts in the treatment of avascular osteonecrosis of the femoral head

Background:

Osteonecrosis of the femoral head (ONFH) is a frequent orthopedic disease leading to destruction of the hip joint and disabling arthritis. Several procedures have been developed to treat the joint deterioration in case of osteonecrosis, trying to avoid or delay an intervention of total hip replacement, especially in young patients. The aim of this study was to analyze the use of autologous bone micrografts derived from cancellous bone in the management of avascular ONFH. The treatment described was implemented using the Rigenera® protocol to obtain autologous micrografts: small fragments of cancellous bone collected by femoral neck, disaggregated and injected in the necrotic area using an empty screw.

Materials and methods:

Twenty adult patients affected by avascular ONFH were enrolled in this study; all patients reported a preoperative intermittent coxo-arthrosis and limited function of intra and extra rotation of the hip. Inclusion criteria were an Oxford Hip Score between (OHS) 20 and 39, a Harris hip score (HHS) showing pre-operative poor results (lower than 70 points) and a stage II-IIIA and IIIB according with the classification proposed by the Association Research Circulation Osseous (ARCO).

Results:

Using an MRI evaluation, after six months, the authors observed a complete regression of necrotic area and the restoration of osseous structure. Clinical outcome has been evaluated at 6-12 and 24 months follow-up. At the final F.U. the HHS rised from poor to good results (mean value at final F.U of 84) while the OHS improved significantly already after 21 days from micrografts injection (mean 35.4 ± 7.5) with an increasing trend until to two-year final FU (mean 37.4 ± 9.5). The full recovery of daily and mild sport activities was reached after 20 and 90 days from intervention, respectively.

Conclusion:

The results of this study are suggestive for a new approach in the treatment of avascular ONFH assuming a process of bone regeneration based on a dual mechanism of action, biological and mechanical, induced by micrografts and injected using an empty screw as vehicle. (www.actabiomedica.it)

In Vitro Characterization of Adipose Stem Cells Non-Enzymatically Extracted from the Thigh and Abdomen

Autologous fat grafting is a surgical technique in which adipose tissue is transferred from one area of the body to another, in order to reconstruct or regenerate damaged or injured tissues. Before reinjection, adipose tissue needs to be purified from blood and cellular debris to avoid inflammation and preserve the graft viability. To perform this purification, different enzymatic and mechanical methods can be used. In this study, we characterized in vitro the product of a closed automatic device based on mechanical disaggregation, named Rigenera^®, focusing on two sites of adipose tissue harvesting. At first, we optimized the Rigenera^® operating timing, demonstrating that 60 s of treatment allows a higher cellular yield, in terms of the cell number and growth rate. This result optimizes the mechanical disaggregation and it can increase the clinical efficiency of the final product. When comparing the extracted adipose samples from the thigh and abdomen, our results showed that the thigh provides a higher number of mesenchymal-like cells, with a faster replication rate and a higher ability to form colonies. We can conclude that by collecting adipose tissue from the thigh and treating it with the Rigenera^® device for 60 s, it is possible to obtain the most efficient product.

Bone Tissue Regeneration in the Oral and Maxillofacial Region: A Review on the Application of Stem Cells and New Strategies to Improve Vascularization

Bone tissue engineering techniques are a promising alternative for the use of autologous bone grafts to reconstruct bone defects in the oral and maxillofacial region. However, for successful bone regeneration, adequate vascularization is a prerequisite. This review presents and discusses the application of stem cells and new strategies to improve vascularization, which may lead to feasible clinical applications. Multiple sources of stem cells have been investigated for bone tissue engineering. The stromal vascular fraction (SVF) of human adipose tissue is considered a promising single source for a heterogeneous population of essential cells with, amongst others, osteogenic and angiogenic potential. Enhanced vascularization of tissue-engineered grafts can be achieved by different mechanisms: vascular ingrowth directed from the surrounding host tissue to the implanted graft, vice versa, or concomitantly. Vascular ingrowth into the implanted graft can be enhanced by (i) optimizing the material properties of scaffolds and (ii) their bioactivation by incorporation of growth factors or cell seeding. Vascular ingrowth directed from the implanted graft towards the host tissue can be achieved by incorporating the graft with either (i) preformed microvascular networks or (ii) microvascular fragments (MF). The latter may have stimulating actions on both vascular ingrowth and outgrowth, since they contain angiogenic stem cells like SVF, as well as vascularized matrix fragments. Both adipose tissue-derived SVF and MF are cell sources with clinical feasibility due to their large quantities that can be harvested and applied in a one-step surgical procedure. During the past years, important advancements of stem cell application and vascularization in bone tissue regeneration have been made. The development of engineered in vitro 3D models mimicking the bone defect environment would facilitate new strategies in bone tissue engineering. Successful clinical application requires innovative future investigations enhancing vascularization.

A Multicentre Study: The Use of Micrografts in the Reconstruction of Full-Thickness Posttraumatic Skin Defects of the Limbs-A Whole Innovative Concept in Regenerative Surgery

The skin graft is a surgical technique commonly used in the reconstructive surgery of the limbs, in order to repair skin loss, as well as to repair the donor area of the flaps and cover the dermal substitutes after engraftment. The unavoidable side effect of this technique consists of unaesthetic scars. In order to achieve the healing of posttraumatic ulcers by means of tissue regeneration and to avoid excessive scarring, a new innovative technology based on the application of autologous micrografts, obtained by Rigenera technology, was reported. This technology was able to induce tissue repair by highly viable skin micrografts of 80 micron size achieved by a mechanical disaggregation method. The specific cell population of these micrografts includes progenitor cells, which in association with the fragment of the Extracellular Matrix (ECM) and growth factors derived by patients' own tissue initiate biological processes of regeneration enhancing the wound healing process. We have used this technique in 70 cases of traumatic wounds of the lower and upper limbs, characterized by extensive loss of skin substance and soft tissue. In all cases, we have applied the Rigenera protocol using skin micrografts, achieving in 69 cases the complete healing of wounds in a period between 35 and 84 days. For each patient, the reconstructive outcome was evaluated weekly to assess the efficacy of this technique and any arising complication. A visual analogue scale (VAS) was administered to assess the amount of pain felt after the micrografts' application, whereas we evaluated the scars according to the Vancouver scale and the wound prognosis according to Wound Bed Score. We have thus been able to demonstrate that Rigenera procedure is very effective in stimulating skin regeneration, while reducing the outcome scar.

Progenitor-cell-enriched micrografts as a novel option for the management of androgenetic alopecia

Regenerative medicine is a multidisciplinary field that combines engineering and life science principles to promote regeneration, potentially restoring the physiological condition in diseased tissues. Specifically, the developments of complex grafts enhance the intrinsic regenerative capacity of the host by altering its environment. Autologous micrografts obtained through Rigenera® micrografting technology are able to promote derma and bone regeneration. Androgenetic alopecia (AGA) leads to a progressive thinning of scalp hair affecting 60-70% of the adult population worldwide. Pharmacological treatment offers moderate results and hair transplantation represents the only permanent treatment option. The aim of this study was to demonstrate the role of dermis micrografting in the treatment of AGA by clinical and histological evaluations after 4, 6, and 12 months. Hair growth and density were improved at all indicated times. Those outcomes were also confirmed by the TrichoScan® analysis, reporting an increase of total hair count and density with an increase and reduction of anagen and telogen phases, respectively. Scalp dermoscopic analysis showed an improvement of hair density and histological analysis indicated a clear amelioration of the scalp, development of hair follicles, and a beginning of cuticle formation. Collectively, those results suggest a possible use of the micrografts as a novel therapeutic option in the management of AGA.

Poly D,L-Lactide-Co-Glycolic Acid Grafting Material in Sinus Lift

The poly D,L-lactide-co-glycolic acid (PLGA) is a copolymer used in many therapeutic devices for its high rates of biodegradability and biocompatibility. The principal aim of the research was to evaluate the new bone formation, after 16 (T1) and 28 weeks (T2), in sheep maxillary sinus lift in vivo model using PLGA.Computerized tomography analysis, X-ray microanalysis, and scanning electron microscope analysis of secondary electrons (SE) and the backscattered electrons (BSE) of the samples were detected.After 28 weeks, the computed tomography analysis showed a 22% increase of UH density in the grafting areas. The X-ray microanalysis of the samples showed calcium and phosphorus increase at T1 and T2 follow-up period and the carbon and oxygen concentration decrease. The SE evaluation showed a rapid superficial resorption of the biomaterials at T1 and a completely bone reorganization of biomaterial at T2. The BSE analysis confirmed the SE data and showed the direct and intimate contact between bone and PLGA with a higher calcification in T2 compared to T1.Certainly, still other experiments and a larger number of samples will be necessary to be analyzed to determine the behavior of the PLGA in the bone regeneration; however, the PLGA used in maxillary sinus lift animal model, seem to promote new bone formation that continues increase at 28 weeks after grafting.

Detection of peri-implant inflammation by the use of a matrix metalloproteinase-8 chair-side test

BACKGROUND

Active matrix metalloproteinase-8 (MMP-8) enzymes are associated with inflammation and the degradation of implant-supporting tissues. A high concentration of these enzymes in the peri-implant sulcular fluid (PISF) has been associated with a pathological condition. The aim of the present study was to evaluate the ability of a chair-side MMP-8 test to individuate pathological peri-implant site. The working hypothesis is that positive response to MMP-8 test corresponds to pathological values of periodontal indexes. A secondary working hypothesis is that PISF sampling method influences the test accuracy.

METHODS

Fifty implants from 50 patients were evaluated during scheduled follow-up appointments in a clinical setting using the MMP-8 chair-side test and periodontal indices (probing depth, bleeding on probing, plaque index and peri-implant inflammation index). Two methods of PISF sampling were tested.

RESULTS

The MMP-8 test demonstrated significant diagnostic capacity and good sensitivity and accuracy regarding indices of bleeding on probing, plaque index, and peri-implant inflammation index but fair agreement.

CONCLUSIONS

Further studies should be performed to better define the interpretation of the MMP-8 chair-test results and their correlation to peri-implant indexes.

Covalently-Linked Hyaluronan versus Acid Etched Titanium Dental Implants: A Crossover RCT in Humans

Biochemical modification of titanium surfaces (BMTiS) entails immobilization of biomolecules to implant surfaces in order to induce specific host responses. This crossover randomized clinical trial assesses clinical success and marginal bone resorption of dental implants bearing a surface molecular layer of covalently-linked hyaluronan in comparison with control implants up to 36 months after loading. Patients requiring bilateral implant rehabilitation received hyaluronan covered implants in one side of the mouth and traditional implants in the other side. Two months after the first surgery, a second surgery was undergone to uncover the screw and to place a healing abutment. After two weeks, the operator proceeded with prosthetic procedures. Implants were evaluated by periapical radiographs and the crestal bone level was recorded at mesial and distal sites—at baseline and up to 36 months. One hundred and six implants were positioned, 52 HY-coated, and 48 controls were followed up. No differences were observed in terms of insertion and stability, wound healing, implant success, and crestal bone resorption at any time considered. All interventions had an optimal healing, and no adverse events were recorded. This trial shows, for the first time, a successful use in humans of biochemical-modified implants in routine clinical practice and in healthy patients and tissues with satisfactory outcomes.

Rationale and pre-clinical evidences for the use of autologous cartilage micrografts in cartilage repair

BACKGROUND

The management of cartilage lesions is an open issue in clinical practice, and regenerative medicine represents a promising approach, including the use of autologous micrografts whose efficacy was already tested in different clinical settings. The aim of this study was to characterize in vitro the effect of autologous cartilage micrografts on chondrocyte viability and differentiation and perform an evaluation of their application in racehorses affected by joint diseases.

MATERIALS AND METHODS

Matched human chondrocytes and micrografts were obtained from articular cartilage using Rigenera® procedure. Chondrocytes were cultured in the presence or absence of micrografts and chondrogenic medium to assess cell viability and cell differentiation. For the pre-clinical evaluation, three racehorses affected by joint diseases were treated with a suspension of autologous micrografts and PRP in arthroscopy interventions. Clinical and radiographic follow-ups were performed up to 4 months after the procedure.

RESULTS

Autologous micrografts support the formation of chondrogenic micromasses thanks to their content of matrix and growth factors, such as transforming growth factor β (TGFβ) and insulin-like growth factor 1 (IGF-1). On the other hand, no significant differences were observed on the gene expression of type II collagen, aggrecan, and SOX9. Preliminary data in the treatment of racehorses are suggestive of a potential in vivo use of micrografts to treat cartilage lesions.

CONCLUSION

The results reported in this study showed the role of articular micrografts in the promoting chondrocyte differentiation suggesting their potential use in the clinical practice to treat articular lesions.

Periosteal Osteogenic Capacity Depends on Tissue Source

Periosteal osteogenic capacity can be exploited to enhance bone formation in the fields of tissue engineering and regenerative medicine. Despite this importance, there have been no studies examining the composition, structure, and osteogenic capacity of periostea from different bone sources. In this study, structure and osteogenic factor content were compared among periostea from rib, calvarial, femoral, and tibial bones, in which the native bones of these four regions were harvested and subjected to histological analysis. The osteogenic capacity of grafted periosteum was evaluated using an in vivo vascularized pedicle model of bone tissue engineering. Poly(ethylene glycol)-poly(l-lactic acid) (PEG-PLLA) copolymer hydrogels were seeded with bone marrow mesenchymal stem cells and implanted with grafted periosteum harvested from either calvarial or tibial bone, which were representative of thin and thick native periostea, respectively. The cambium layer thickness of periostea from the femoral and tibial bones (36.9% ± 2.5% and 36.8% ± 2.6%) was greater than that from the calvarial and rib bones (26.8% ± 2.4% and 25.5% ± 1.9%). The osteocalcin and alkaline phosphatase levels were comparatively higher in the femoral and tibial periostea than those in periostea harvested from the calvarial and rib bones. The construct implanted with grafted tibial periosteum resulted in greater neo-bone regeneration and higher osteocalcin and alkaline phosphatase expression. This study is the first investigation of the osteogenic capacity of periostea from diverse sources. The results can be used to guide clinical strategies that exploit periostea for tissue engineering and clinical applications.

Recent Advances in Nanocomposites Based on Aliphatic Polyesters: Design, Synthesis, and Applications in Regenerative Medicine

In the last decade, biopolymer matrices reinforced with nanofillers have attracted great research efforts thanks to the synergistic characteristics derived from the combination of these two components. In this framework, this review focuses on the fundamental principles and recent progress in the field of aliphatic polyester-based nanocomposites for regenerative medicine applications. Traditional and emerging polymer nanocomposites are described in terms of polymer matrix properties and synthesis methods, used nanofillers, and nanocomposite processing and properties. Special attention has been paid to the most recent nanocomposite systems developed by combining alternative copolymerization strategies with specific nanoparticles. Thermal, electrical, biodegradation, and surface properties have been illustrated and correlated with the nanoparticle kind, content, and shape. Finally, cell-polymer (nanocomposite) interactions have been described by reviewing analysis methodologies such as primary and stem cell viability, adhesion, morphology, and differentiation processes.

Evaluation of Poly(Lactic-co-glycolic) Acid Alone or in Combination with Hydroxyapatite on Human-Periosteal Cells Bone Differentiation and in Sinus Lift Treatment

Most recent advances in tissue engineering in the fields of oral surgery and dentistry have aimed to restore hard and soft tissues. Further improvement of these therapies may involve more biological approaches and the use of dental tissue stem cells in combination with inorganic/organic scaffolds. In this study, we analyzed the osteoconductivity of two different inorganic scaffolds based on poly (lactic-co-glycolic) acid alone (PLGA-Fisiograft) or in combination with hydroxyapatite (PLGA/HA-Alos) in comparison with an organic material based on equine collagen (PARASORB Sombrero) both in vitro and in vivo. We developed a simple in vitro model in which periosteum-derived stem cells were grown in contact with chips of these scaffolds to mimic bone mineralization. The viability of cells and material osteoconductivity were evaluated by osteogenic gene expression and histological analyses at different time points. In addition, the capacity of scaffolds to improve bone healing in sinus lift was examined. Our results demonstrated that the osteoconductivity of PLGA/HA-Alos and the efficacy of scaffolds in promoting bone healing in the sinus lift were increased. Thus, new clinical approaches in sinus lift follow-up should be considered to elucidate the clinical potential of these two PLGA-based materials in dentistry.