Injectable soft-tissue augmentation by tissue engineering and regenerative medicine with human mesenchymal stromal cells, platelet-rich plasma and hyaluronic acid scaffolds

Three-dimensional cultures of gingival fibroblasts on fibrin-based scaffolds for gingival augmentation: A proof-of-concept study

OBJECTIVE

Gingival tissue regeneration is associated with several challenges. Tissue engineering regenerates the different components of the tissues, providing three major elements: living cells, appropriate scaffolds, and tissue-inducing substances. This study aimed to regenerate the gingival connective tissue in vitro, using human gingival fibroblasts cultured in three-dimensional fibrin gel scaffolds.

DESIGN

Human gingival fibroblasts were seeded in a novel three-dimensional fibrin gel scaffold and maintained in two media types: platelet lysate media (control) and collagen-stimulating media (test). Cellular viability and proliferation were assessed, and the production of collagen and other extracellular matrix components in these constructs was investigated and compared.

RESULTS

Human gingival fibroblasts cultured in three-dimensional cultures were metabolically active and proliferated in both media. Furthermore, histologic sections, scanning electron microscopy, and quantitative polymerase chain reaction confirmed the production of higher levels of collagen and other extracellular matrix fibers in three-dimensional constructs cultured in collagen-stimulating media.

CONCLUSIONS

Culturing human gingival fibroblasts in a novel three-dimensional fibrin gel scaffold containing collagen-stimulating media resulted in a tissue-equivalent construct that mimics human gingival connective tissue. The impact of these results should be considered for further investigations, which may help to develop a compatible scaffold for gingival soft tissue regeneration and treatment of mucogingival deformities.

The potential of platelet-rich plasma injections and stem cell therapy for penile rejuvenation

Penile concerns include erectile dysfunction (ED) and Peyronie disease (PD). Restorative therapies including Stem Cell Therapy (SCT) and Platelet Rich Plasma (PRP) injections are proposed to treat these concerns. SCT encompasses the harvesting and injection of mesenchymal stem cells or stromal vascular fractions from various tissue sources. PRP is derived autologously from a patient's plasma and is then injected into the penile tissue. These therapies repair damaged penile tissue and promote both new cellular and vascular growth, as demonstrated in basic science studies. Human trials on SCT and PRP for both ED and PD and have yielded promising results with few side effects. While encouraging, small cohort size and lack of blinding or placebo control limit these studies' external validity. Recently, the first double-blinded randomized controlled trial on PRP for ED was published, providing significant evidence of efficacy. With the rapid commercial availability of SCT and PRP for ED and PD, it is imperative to perform more randomized and placebo-controlled trials with standardized procedures and preparations to evaluate efficacy and safety. This narrative review will summarize the available literature on these penile restorative therapies to date.

Crosslinked Hyaluronic Acid Gels with Blood-Derived Protein Components for Soft Tissue Regeneration

Hyaluronic acid (HA) is an ideal initial material for preparing hydrogels, which may be used as scaffolds in soft tissue engineering based on their advantageous physical and biological properties. In this study, two crosslinking agents, divinyl sulfone (DVS) and butanediol diglycidyl ether, were used to investigate their effect on the properties of HA hydrogels. As HA hydrogels alone do not promote cell adhesion on the scaffold, fibrin and serum from platelet-rich fibrin (SPRF) were combined with the scaffold; the aim was to create a material intended to be used as soft tissue implant that facilitates new tissue formation, and degrades over time. The chemical changes were characterized and cell attachment capacity of the protein-containing gels was examined using human mesenchymal stem cells, and viability was assessed using live-dead staining. Fourier-transform infrared measurements revealed that linking fibrin into the gel was more effective than linking SPRF. The scaffolds were found to be able to support cell adherence onto the hydrogels, and the best result was achieved when HA was crosslinked with DVS and contained fibrin. The most promising derivative, 5% DVS-crosslinked fibrin-containing hydrogel, was injected subcutaneously into C57BL/6 mice for 12 weeks. The scaffold was proven to be biocompatible, remodeling, and vascularization occurred, while shape and integrity were maintained. Impact statement Fibrin was combined with crosslinked hyaluronic acid (HA) for regenerative application, the structure of the combination of crosslinked HA with blood-derived protein was analyzed and effective coating was proven. It was observed that the fibrin content led to better mesenchymal stem cell attachment in vitro. The compositions showed biocompatibility, connective tissue and vascularization took place when implanted in vivo. Thus, a biocompatible, injectable gel was produced, which is a potential candidate for soft tissue implantation.

Combined therapy with Endoret-Gel and plasma rich in growth factors vs Endoret-Gel alone in the management of facial rejuvenation: A comparative study

BACKGROUND

Skin suffers progressive decrement. An endogenous regenerative technology has been developed that has the versatility to provide an autologous injectable gel (Endoret-Gel) or a liquid plasma rich in growth factors (PRGF) based on the patient´s own platelet-rich plasma.

AIMS

To compare the efficacy of the combined therapy with Endoret-Gel and PRGF versus Endoret-Gel alone in the management of facial rejuvenation.

METHODS

Twenty clinically diagnosed patients with aged skin received either Endoret-Gel monotherapy or Endoret-Gel + PRGF combined therapy. Patients underwent three sessions at one-month intervals and were clinically assessed for six months. Corneometry, sebumetry, and high-resolution topographic analysis were carried out. Patient self-assessment questionnaires and clinical improvement scores were also performed.

RESULTS

The combined therapy showed to promote a higher hydration index. These results were also significant for spot improvement at three months, while conversely, monotherapy with Endoret-Gel demonstrated higher UV spot improvement. A significant decrease of sebum production and wrinkle development was observed for both treatment groups. Red areas also improved in a similar way at the end of the follow-up period. After Endoret-Gel or Endoret-Gel + PRGF therapy, 30% and 70% of patients referred to be very satisfied, respectively. Accordingly, 40% and 80% showed a "very improved" esthetic performance. None of the patients reported a negative change and no adverse events were recorded.

CONCLUSION

Both Endoret-Gel monotherapy and the combined treatment with PRGF were shown to promote facial rejuvenation and to palliate the age-related cutaneous atrophy. The combined therapy may exert a synergistic effect that addresses both skin quality improvement and soft tissue restoration in a shorter period.

State of the Art on Biomaterials for Soft Tissue Augmentation in the Oral Cavity. Part II: Synthetic Polymers-Based Biomaterials

Most of the polymers used as biomaterials for scaffolds are naturally occurring, synthetic biodegradable, and synthetic non-biodegradable polymers. Since synthetic polymers can be adapted for obtaining singular desired characteristics by applying various fabrication techniques, their use has increased in the biomedical field, in dentistry in particular. The manufacturing methods of these new structures include many processes, such as electrospinning, 3D printing, or the use of computer-aided design/computer-aided manufacturing (CAD/CAM). Synthetic polymers show several drawbacks that can limit their use in clinical applications, such as the lack of cellular recognition, biodegradability, and biocompatibility. Moreover, concerning biodegradable polymers, the time for matrix resorption is not predictable, and non-resorbable matrices are preferred for soft tissue augmentation in the oral cavity. This review aimed to determine a new biomaterial to offset the present shortcomings in the oral environment. Researchers have recently proposed a novel non-resorbable composite membrane manufactured via electrospinning that has allowed obtaining remarkable in vivo outcomes concerning angiogenesis and immunomodulation throughout the polarization of macrophages. A prototype of the protocol for in vitro and in vivo experimentation with hydrogels is explained in order to encourage innovation into the development of promising biomaterials for soft tissue augmentation in the near future.

Long-term stability of a novel platelet-rich plasma-based topical serum for cutaneous applications

BACKGROUND

Skin alterations are usually related to chronic diseases that demand sustained and long-term dosages; hence, it is pivotal that the stability of treatments is preserved. A novel storable and endogenous topical serum (ES) based on the patient's own blood has been recently developed.

AIMS

To investigate the long-term stability of the formulation and to provide preliminary data of its biologic potential.

METHODS

Samples from six donors were obtained and either used as fresh samples or cold-stored for 6 months. Physicochemical, rheological, and biological stability of the formulation was determined.

RESULTS

Endogenous topical serum maintained unaltered its organoleptic properties, viscosity, pH, spreadability index, and sterility. The growth factor content including TGFβ-I, EGF, PDGF-AB, HGF, and Ang-I showed no decrease. In contrast, ES showed lower levels of IGF-I once stored. Dermal fibroblasts showed no change in their proliferative activity.

CONCLUSION

Endogenous topical serum showed to maintain its physicochemical and biological properties after six months of storage. ES might reduce the frequency of blood extractions and would enable patients with chronic disorders to maintain a daily use of the product in a minimally invasive way.

Hyaluronic Acid: Redefining Its Role

The discovery of several unexpected complex biological roles of hyaluronic acid (HA) has promoted new research impetus for biologists and, the clinical interest in several fields of medicine, such as ophthalmology, articular pathologies, cutaneous repair, skin remodeling, vascular prosthesis, adipose tissue engineering, nerve reconstruction and cancer therapy. In addition, the great potential of HA in medicine has stimulated the interest of pharmaceutical companies which, by means of new technologies can produce HA and several new derivatives in order to increase both the residence time in a variety of human tissues and the anti-inflammatory properties. Minor chemical modifications of the molecule, such as the esterification with benzyl alcohol (Hyaff-11® biomaterials), have made possible the production of water-insoluble polymers that have been manufactured in various forms: membranes, gauzes, nonwoven meshes, gels, tubes. All these biomaterials are used as wound-covering, anti-adhesive devices and as scaffolds for tissue engineering, such as epidermis, dermis, micro-vascularized skin, cartilage and bone. In this review, the essential biological functions of HA and the applications of its derivatives for pharmaceutical and tissue regeneration purposes are reviewed.

Minimally invasive procedures for deficient interdental papillae: A review

OBJECTIVE

Deficient interdental papillae cause a series of problems, including food impaction, phonetic difficulties, and esthetic concerns. The purpose of this article is to provide valid clinical recommendations for clinicians to address these problems in a predictable and less invasive way.

OVERVIEW

Numerous treatments are available for interdental papillae reconstruction, but most of them involve surgery and yield unpredictable outcomes. Minimally invasive treatments have the advantages of being effective, predictable, and involving only slight injury as compared to surgical treatments. We included 66 studies obtained after searching for relevant papers in PubMed and Web of Science. The etiology and classification of deficient interdental papillae are explained and minimally invasive procedures for deficient interdental papillae reconstruction are summarized.

CONCLUSIONS

Minimally invasive procedures are promising ways to reconstruct deficient interdental papillae, and have the advantages of slight pain and rapid recovery. It should be noticed that some of the minimally invasive treatments still require further long-term observation to confirm their efficacy.

CLINICAL SIGNIFICANCE

Familiarity with etiology and classification of deficient interdental papillae can help clinicians to choose the appropriate minimally invasive approach as well as help with case collection to enhance esthetics status in patients with deficient interdental papillae.

The use of autologous platelet-rich plasma (PRP) versus no intervention in women with low ovarian reserve undergoing fertility treatment: a non-randomized interventional study

PURPOSE

To investigate the impact of a 3-month course of intracortical injections of autologous platelet-rich plasma (PRP) upon ovarian reserve markers versus no intervention in women with low ovarian reserve prior to undergoing assisted reproductive technology (ART).

METHODS

Prospective controlled, non-randomized comparative study conducted in a private fertility clinic, in Venezuela. Women with abnormal ovarian reserve markers (FSH, AMH and AFC) who declined oocyte donation were allocated to one of the following groups according to patient choice: monthly intracortical ovarian PRP injections for three cycles, or no intervention. Primary outcomes were the change in FSH, AMH and AFC pre- and post-treatment. Secondary outcomes included the number of oocytes collected and fertilized, biochemical/clinical pregnancy rates and miscarriage and live birth rates.

RESULTS

Eighty-three women were included, of which 46 received PRP treatment and 37 underwent no intervention. Overall median age was 41 years (IQR 39-44). There were no demographic differences between the study groups. At the 3-month follow-up, women treated with PRP experienced a significant improvement in FSH, AMH and AFC, whereas there was no change in the control group. Furthermore, overall rates of biochemical (26.1% versus 5.4%, P = 0.02) and clinical pregnancy (23.9% versus 5.4%, P = 0.03) were higher in the PRP group, while there was no difference in the rates of first trimester miscarriage and live birth between groups.

CONCLUSION

PRP injections are effective and safe to improve markers of low ovarian reserve prior to ART, although further evidence is required to evaluate the impact of PRP on pregnancy outcomes.

Hybrid 3D Printing of Synthetic and Cell-Laden Bioinks for Shape Retaining Soft Tissue Grafts

Despite recent advances in clinical procedures, the repair of soft tissue remains a reconstructive challenge. Current technologies such as synthetic implants and dermal flap autografting result in inefficient shape retention and unpredictable aesthetic outcomes. 3D printing, however, can be leveraged to produce superior soft tissue grafts that allow enhanced host integration and volume retention. Here, a novel dual bioink 3D printing strategy is presented that utilizes synthetic and natural materials to create stable, biomimetic soft tissue constructs. A double network ink composed of covalently crosslinked poly(ethylene) glycol and ionically crosslinked alginate acts as a physical support network that promotes cell growth and enables long-tersm graft shape retention. This is coupled with a cell-laden, biodegradable gelatin methacrylate bioink in a hybrid printing technique, and the composite scaffolds are evaluated in their mechanical properties, shape retention, and cytotoxicity. Additionally, a new shape analysis technique utilizing CloudCompare software is developed that expands the available toolbox for assessing scaffold aesthetic properties. With this dynamic 3D bioprinting strategy, complex geometries with robust internal structures can be easily modulated by varying the print ratio of non-degradable to sacrificial strands. The versatility of this hybrid printing fabrication platform can inspire the design of future multi-material regenerative implants.

A novel protein-based autologous topical serum for skin regeneration

BACKGROUND

As skin ages, a functional decrement occurs. To avoid future vulnerability to dermatologic diseases, an optimal cutaneous regeneration is mandatory. Biological therapies based on blood-derived autologous proteins are gaining attention of scientists and dermatologists.

OBJECTIVES

A novel 100% autologous topical serum has been developed using plasma rich in growth factors technology. The physicochemical characterization and the biologic potential of the novel formulation have been studied.

METHODS

Rheological and mechanical properties and the biological capacity of the formulation were characterized. Human dermal fibroblast culture and 3D organotypic skin explants were used as in vitro and ex vivo cutaneous models, respectively.

RESULTS

The autologous topical serum presented an optimal spreadability index and appropriate shear thinning behavior that allowed an easy handling and rapid integration within the cutaneous tissue. The formulation has a high growth factor load with the ability to progressively penetrate into the dermal/epidermal layers of the skin. It is biocompatible and promotes cell proliferation and chemotactic activity. The autologous topical serum promotes the biosynthetic activity of cells by the stimulation of collagen and hyaluronic acid expression.

CONCLUSIONS

These findings present an in situ and easy to prepare autologous topical serum based on the patient's own blood with physicochemical and bioactive properties that may be used for skin regeneration purposes.

Review of methodology and materials using for building of gum soft tissues

In the review we analyze the basic surgical techniques applied to increase the volume of a keratinized gum and materials used for this procedure, such as dermal and collagen matrices. The results of clinical trials are presented on the effectiveness of collagen matrices, including Mucograft. The analysis of the literature highlights the main advantages and disadvantages of these methods and materials, as well as the most significant and promising areas for the further clinical research.

Current Therapeutic Strategies for Adipose Tissue Defects/Repair Using Engineered Biomaterials and Biomolecule Formulations

Tissue engineered scaffolds for adipose restoration/repair has significantly evolved in recent years. Patients requiring soft tissue reconstruction, caused by defects or pathology, require biomaterials that will restore void volume with new functional tissue. The gold standard of autologous fat grafting (AFG) is not a reliable option. This review focuses on the latest therapeutic strategies for the treatment of adipose tissue defects using biomolecule formulations and delivery, and specifically engineered biomaterials. Additionally, the clinical need for reliable off-the-shelf therapies, animal models, and challenges facing current technologies are discussed.

Autologous Adipose-Derived Tissue Matrix Part II: Implantation Biology

BACKGROUND

In part 1 of this study it was shown that liposuctioned fat could be a sufficient source of autologous collagen for use as a filler or in reconstruction. The collagen composition in liposuctioned fat was shown to form a cross-linked helical matrix composed of types II, III, and IV. Additionally, viable adipocytes and fibroblasts among other cells were found.

OBJECTIVES

The purpose of this research was to study the biology of this matrix after subsequent implantation compared to Juvederm (Allergan, Parsippany, NJ) common soft tissue filler.

METHODS

Fat was obtained from individuals undergoing routine liposuction and was processed by a two-step process to obtain a connective tissue matrix. The matrix was then cryo-frozen for a minimum of 4 weeks after which it was thawed and implanted in 46 nude mice. Juvederm Ultra was used as the control article and the animals followed for one year.

RESULTS

Liposuctioned fat was obtained from 10 individuals and processed as previously described. Mice were harvested at 3, 6, 9, and 12 months and histology obtained. There were no adverse effects from either article and the bio-reactivity rating was 0. The implanted collagen compared favorably to Juvederm at all stages and was found to be replaced by new collagen and fat.

CONCLUSIONS

A collagen matrix with viable cells for autologous use can be obtained from liposuctioned fat which has been processed and cryo-frozen. The material lasts at least one year and is slowly replaced by new collagenand fat.

LEVEL OF EVIDENCE

5.

Minipig-BMSCs Combined with a Self-Setting Calcium Phosphate Paste for Bone Tissue Engineering

Calcium phosphate cements (CPCs) are a new generation of bone repair materials with good biocompatibility for various stem cells. The minipig is a recommended large animal model for bone engineering research. This study aimed to evaluate the feasibility of utilizing CPC scaffolds for the adhesion, proliferation, and osteogenic differentiation of minipig's bone marrow mesenchymal stem cells (pBMSCs). Passage 3 pBMSCs were seeded on the CPC scaffold and cultured with osteogenic culture medium (osteogenic group) or normal medium (control group). The density of viable cells increased in both groups, and pBMSCs firmly attached and spread well on the CPC scaffold. The alkaline phosphatase (ALP) activity in the osteogenic group had significantly increased on day 7 (D7) and peaked on D14. qRT-PCR revealed that mRNA levels of ALP and three osteogenic marker genes were significantly higher on D4, D7, and D14 in the osteogenic group. Alizarin Red S staining showed a significantly higher degree of bone mineralization from D7, D14 to D21 in the osteogenic group. These results indicated that pBMSCs can attach, proliferate well on CPC scaffold, and be successfully induced to differentiate into osteogenic cells. Our findings may be helpful for bone tissue engineering and the studies of bone regeneration.

Platelet-rich plasma and hyaluronic acid - an efficient biostimulation method for face rejuvenation

BACKGROUND

Cosmetic applications of platelet-rich plasma (PRP) are new, and reports are scarce and dispersed in the literature. There are a variety of commercially available kits and injection techniques, and the number and intervals of injections vary. New investigations should focus on developing a standardized procedure for PRP preparation and application methods to augment its efficacy and potency.

OBJECTIVES

In this report, we aim to provide data and commentary to assist and add to current guidelines.

METHODS

A series of 94 female patients with varying degrees of facial aging signs were treated with PRP and hyaluronic acid (HA). Mean age was 53.0 ± 5.6. The mean injection number was 3.6 ± 2.0. Platelet-poor and platelet- rich plasma parts were mixed with 0.5 cc %3.5 hyaluronic acid and 0.5 cc procaine and injected with a 30G, 13-mm needle into deep dermis and hypodermis. Patients were asked to rate their personal satisfaction with their skin texture, pigmentation, and sagging. In addition, the overall results were rated by three independent physicians and the patients themselves. The outcomes were peer-reviewed, and correlations between the degree of the aesthetic scores and the number of injections were explored.

RESULTS

There was a statistically significant difference in general appearance, skin firmness-sagging and skin texture according to the patients' before and after applications of PRP. A statistically significant correlation was found between the number of injections and overall satisfaction.

CONCLUSIONS

Compared to the baseline, the PRP and HA injections provided clinically visible and statistically significant improvement on facial skin. The improvements were more remarkable as the injection numbers increased.

Programmed cell delivery from biodegradable microcapsules for tissue repair

Injectable and resorbable hydrogels are an extremely attractive class of biomaterials. They make it possible to fill tissue defects accurately with an undoubtedly minimally invasive approach and to locally deliver cells that support repair or regeneration processes. However, their use as a cell carrier is often hindered by inadequate diffusion in bulk. A possible strategy for overcoming this transport limitation might be represented by injection of rapidly degradable cell-loaded microcapsules, so that maximum material thickness is limited by sphere radius. Here, the possibility of achieving programmable release of viable cells from alginate-based microcapsules was explored in vitro, by evaluating variations in material stability resulting from changes in hydrogel composition and assessing cell viability after encapsulation and in vitro release from microcapsules. Degradation of pure alginate microspheres was varied from a few days to several weeks by varying sodium alginate and calcium chloride concentrations. The addition of poloxamer was also found to accelerate degradation significantly, with capsule breakdown almost complete by two weeks, while chitosan was confirmed to strengthen alginate cross-linking. The presence of viable cells inside microspheres was revealed after encapsulation, and released cells were observed for all the formulations tested after a time interval dependent on bead degradation speed. These findings suggest that it may be possible to fine tune capsule breakdown by means of simple changes in material formulation and regulate, and eventually optimize, cell release for tissue repair.

Biomimetic 3D tissue printing for soft tissue regeneration

Engineered adipose tissue constructs that are capable of reconstructing soft tissue with adequate volume would be worthwhile in plastic and reconstructive surgery. Tissue printing offers the possibility of fabricating anatomically relevant tissue constructs by delivering suitable matrix materials and living cells. Here, we devise a biomimetic approach for printing adipose tissue constructs employing decellularized adipose tissue (DAT) matrix bioink encapsulating human adipose tissue-derived mesenchymal stem cells (hASCs). We designed and printed precisely-defined and flexible dome-shaped structures with engineered porosity using DAT bioink that facilitated high cell viability over 2 weeks and induced expression of standard adipogenic genes without any supplemented adipogenic factors. The printed DAT constructs expressed adipogenic genes more intensely than did non-printed DAT gel. To evaluate the efficacy of our printed tissue constructs for adipose tissue regeneration, we implanted them subcutaneously in mice. The constructs did not induce chronic inflammation or cytotoxicity postimplantation, but supported positive tissue infiltration, constructive tissue remodeling, and adipose tissue formation. This study demonstrates that direct printing of spatially on-demand customized tissue analogs is a promising approach to soft tissue regeneration.

Award winner for outstanding research in the PhD category, 2014 Society for Biomaterials annual meeting and exposition, Denver, Colorado, April 16-19, 2014: Decellularized adipose matrix hydrogels stimulate in vivo neovascularization and adipose formation

Decellularization of tissues offers the ability to produce tissue-specific extracellular matrix (ECM) scaffolds that recreate many of the biochemical aspects of the tissue of interest. In this study, we describe the in vivo function of decellularized adipose ECM hydrogels for treating subcutaneous adipose deficits. Adipose ECM hydrogels were combined with either adipose-derived adult stem cells or a biocompatible cross-linker, injected subcutaneously into nude mice, and evaluated over the course of 1 month. These ECM hydrogels showed improved integration with the surrounding tissue in vivo compared to a clinical standard soft tissue filler, Juvederm, and stimulated neovascularization. More importantly, these adipose ECM hydrogels facilitated new adipose regeneration within the material at 1 month, a feature not seen with current clinical soft tissue fillers. These results contribute to the growing evidence that ECM-based materials are capable of stimulating subcutaneous adipose regeneration, suggesting that future soft tissue filler materials could incorporate ECM elements in order to restore function to adipose deficits instead of simply filling them with static materials.

Papilla regeneration by injectable stem cell therapy with regenerative medicine: long-term clinical prognosis

Black triangle (BT), an open interproximal space between teeth, can cause aesthetic concerns, food impaction, phonetic difficulties and periodontitis. The aim of this study was to determine the possibility and long-term prognosis of novel papilla regeneration with regenerative medicine, i.e. tissue-engineered papilla (TEP), and to investigate the potential of a tissue-engineering method for soft-tissue augmentation, especially aesthetic improvement of BT, with mesenchymal stem cells (MSCs) as the isolated cells, platelet-rich plasma (PRP) as the growth factor and hyaluronic acid (HA) as the scaffold. The parameters were assessed from a clinical point of view by measuring the distance from the tip of the interproximal papilla to the base of the contact area in each study region. The mean volumes, operation times and follow-up periods of TEP were 1.32 ± 0.25 ml, 2.2 ± 1.62 times and 55.3 ± 17.7 months; the mean improved BT values were 2.55 ± 0.89 mm. An aesthetic improvement was achieved. TEP was able to provide aesthetic improvement of black triangle and predictable results, and could emerge as another novel option for periodontal regenerative therapy in periodontal diseases.

Adipose tissue regeneration: a state of the art

Adipose tissue pathologies and defects have always represented a reconstructive challenge for plastic surgeons. In more recent years, several allogenic and alloplastic materials have been developed and used as fillers for soft tissue defects. However, their clinical use has been limited by further documented complications, such as foreign-body reactions potentially affecting function, degradation over time, and the risk for immunogenicity. Tissue-engineering strategies are thus being investigated to develop methods for generating adipose tissue. This paper will discuss the current state of the art in adipose tissue engineering techniques, exploring the biomaterials used, stem cells application, culture strategies, and current regulatory framework that are in use are here described and discussed.

Regenerative surgery of the complications with Morton's neuroma surgery: use of platelet rich plasma and hyaluronic acid

Morton's neuroma is an entrapment neuropathy of the plantar digital nerve. We treated five patients with wound dehiscence and tendon exposure, after Morton's neuroma surgery excision using a dorsal approach. In this article we describe our technique. From July 2010 to August 2011, at the Department of Plastic and Reconstructive Surgery, University of Rome 'Tor Vergata', five patients (four females and one male), with ages ranging between 35 and 52 years, were treated with a combination of PRP (platelet rich plasma) and HA (hyaluronic acid). Thirty days following surgery, all patients showed a complete healing of the wound. The use of this technique for the treatment of postoperative wound dehiscence and tendon exposure has proven as satisfactory.

Injectable biomaterials for adipose tissue engineering

Adipose tissue engineering has recently gained significant attention from materials scientists as a result of the exponential growth of soft tissue filler procedures being performed within the clinic. While several injectable materials are currently being marketed for filling subcutaneous voids, they often face limited longevity due to rapid resorption. Their inability to encourage natural adipose formation or ingrowth necessitates repeated injections for a prolonged effect and thus classifies them as temporary fillers. As a result, a significant need for injectable materials that not only act as fillers but also promote in vivo adipogenesis is beginning to be realized. This paper will discuss the advantages and disadvantages of commercially available soft tissue fillers. It will then summarize the current state of research using injectable synthetic materials, biopolymers and extracellular matrix-derived materials for adipose tissue engineering. Furthermore, the successful attributes observed across each of these materials will be outlined along with a discussion of the current difficulties and future directions for adipose tissue engineering.

A cellular delivery system fabricated with autologous BMSCs and collagen scaffold enhances angiogenesis and perfusion in ischemic hind limb

Although therapeutic cellular angiogenesis is effective for chronic ischemia, the optimal mode of cellular administration is still under exploration. This study aimed to develop a cellular delivery system to enhance the perfusion and angiogenesis in the ischemic hind limb. Collagen scaffold (CS) was prepared, and for morphology and toxicity analysis, bone marrow-derived mesenchymal stem cells (BMSCs) were isolated, expanded, filtrated, and seeded onto CS to construct BMSCs-CS. The ischemic hind limbs of rabbit models were implanted with autologous BMSCs-CS, CS, and autologous BMSCs; the untreated ischemic or normal animals were considered as the ischemic or normal control groups. Oxygen saturation parameters were regularly measured to determine the perfusion in the extremities. Histological examinations with hematoxylin and eosin immunostaining against von Willebrand factor and smooth muscle (SM) α-actin were performed for capillary and mature vessel evaluation. CS was a multiporous structure without cytotoxicity. At several intervals, the oxygen saturation ratio (OSR) in normal control was the highest. The OSRs in BMSCs-CS and CS were higher than that in BMSCs and ischemic control (p < 0.05); the OSR in BMSCs-CS group was higher than that in CS at 6 and 8 weeks (p < 0.05). The capillaries in BMSCs-CS and CS were higher than that in CS, BMSCs, and the ischemic or normal control (p < 0.05). The mature vessels in BMSCs-CS were higher than that in CS, BMSCs, and the ischemic or normal control (p < 0.05). The autologous cellular delivery system proved to be an effective approach for improving higher ischemic hind limb perfusion and angiogenesis as opposed to cellular therapy alone.

Acellular dermal matrix seeded with adipose-derived stem cells as a subcutaneous implant

BACKGROUND

Soft tissue augmentation using autologous materials usually is associated with high resorption rates. To obtain more durable soft tissue filler, acellular dermal matrix (ADM) was seeded with adipose-derived stem cells (ASCs) in this study.

METHODS

For ADM preparation, split-thickness skin was obtained from the dorsum of two Fischer rats. Harvested skin was acellularized to obtain ADM and subsequently seeded in vitro with ASCs isolated from the same rats. Subcutaneous soft tissue augmentation was carried out in the dorsal area of 20 Fischer rats. The implant materials were ADM (group 1), ADM with ASCs (group 2), collagen type 1 gel (group 3), and collagen type 1 gel with ASCs (group 4). Each specimen was harvested after 8 weeks for quantitative evaluation of thickness, vascular density, and collagen content.

RESULTS

Histologic analysis showed that ASCs were successfully seeded onto ADM. The thickness of the implanted material and the vascular density were highest 8 weeks postoperatively in group 2. The subpanniculus layer became significantly thicker in group 3 than in group 4. The collagen content was significantly higher in group 2 than in the other groups.

CONCLUSION

These findings suggest that ADM seeded with ASCs forms the best implant material in terms of volume maintenance, vascular density, and collagen content.

Biopolymer-based hydrogels as scaffolds for tissue engineering applications: a review

Hydrogels are physically or chemically cross-linked polymer networks that are able to absorb large amounts of water. They can be classified into different categories depending on various parameters including the preparation method, the charge, and the mechanical and structural characteristics. The present review aims to give an overview of hydrogels based on natural polymers and their various applications in the field of tissue engineering. In a first part, relevant parameters describing different hydrogel properties and the strategies applied to finetune these characteristics will be described. In a second part, an important class of biopolymers that possess thermosensitive properties (UCST or LCST behavior) will be discussed. Another part of the review will be devoted to the application of cryogels. Finally, the most relevant biopolymer-based hydrogel systems, the different methods of preparation, as well as an in depth overview of the applications in the field of tissue engineering will be given.

Injectable hydrogel scaffold from decellularized human lipoaspirate

Soft tissue fillers are rapidly gaining popularity for aesthetic improvements or repair of adipose tissue deficits. Several injectable biopolymers have been investigated for this purpose, but often show rapid resorption or limited adipogenesis and do not mimic the native adipose extracellular matrix (ECM). We have generated an injectable adipose matrix scaffold by efficiently removing both the cellular and lipid contents of human lipoaspirate. The decellularized material retained the complex composition of peptides and glycosaminoglycans found in native adipose ECM. This matrix can be further processed by solubilizing the extracted ECM to generate a thermally responsive hydrogel that self-assembles upon subcutaneous injection. This hydrogel also supports the growth and survival of patient matched adipose-derived stem cells in vitro. The development of an injectable hydrogel from human lipoaspirate represents a minimally invasive option for adipose tissue engineering in terms of both the collection of source material and delivery of the scaffold.