Future of fat as raw material for tissue regeneration

Exosomes Derived from Hypoxia-Cultured Human Adipose Stem Cells Alleviate Articular Chondrocyte Inflammaging and Post-Traumatic Osteoarthritis Progression

Osteoarthritis (OA) is the most common age-related degenerative joint disease. Inflammaging, linking inflammation and aging, is found in senescent cells with the secretions of matrix-degrading proteins and proinflammatory cytokines. The senescence-associated secretory phenotype (SASP) plays a very important role in OA progression. However, there remains no effective way to suppress OA progression, especially by suppressing inflammaging and/or the chondrocyte SASP. Recent studies have shown that exosomes derived from hypoxia-cultured BMSCs can regenerate cartilage in OA animal models. Some reports have further indicated that exosomes secreted from MSCs contribute to the efficacy of MSC therapy in OA. However, whether hypoxia-cultured ADSC-secreted exosomes (hypoxia-ADSC-Exos) can alleviate the chondrocyte SASP or OA progression remains unclear. Accordingly, we hypothesized that hypoxia-ADSC-Exos have a beneficial effect on the normal functions of human articular chondrocytes (HACs), can attenuate the SASP of OA-like HACs in vitro, and further suppress OA progression in rats. Hypoxia-ADSC-Exos were derived from ADSCs cultured in 1% O2 and 10% de-Exo-FBS for 48 h. The molecular and cell biological effects of hypoxia-ADSC-Exos were tested on IL1-β-induced HACs as OA-like HACs in vitro, and the efficacy of OA treatment was tested in ACLT-induced OA rats. The results showed that hypoxia-ADSC-Exos had the best effect on GAG formation in normal HACs rather than those cultured in normoxia or hypoxia plus 2% de-Exo-FBS. We further found that hypoxia-ADSC-Exos alleviated the harmful effect in OA-like HACs by decreasing markers of normal cartilage (GAG and type II collagen) and increasing markers of fibrous or degenerative cartilage (type I or X collagen), matrix degradation enzymes (MMP13 and ADAMT5), and inflammatory cytokines (TNFα and IL-6). More importantly, intra-articular treatment with hypoxia-ADSC-Exos suppressed OA progression, as evidenced by the weight-bearing function test and cartilage GAG quantification in ACLT rats. Moreover, through NGS and bioinformatic analysis, seven potential miRNAs were found in hypoxia-ADSC-Exos, which may contribute to regulating cellular oxidative stress and attenuating cell senescence. In summary, we demonstrated that hypoxia-ADSC-Exos, carrying potent miRNAs, not only improve normal HAC function but also alleviate HAC inflammaging and OA progression. The results suggest that hypoxia-ADSC-Exo treatment may offer another strategy for future OA therapy.

Developing a clinical grade human adipose decellularized biomaterial

While tissue engineering investigators have appreciated adipose tissue as a repository of stromal/stem cells, they are only now beginning to see its value as a decellularized tissue resource. Independent academic investigators have successfully extracted lipid, genomic DNA and proteins from human fat to create a decellularized extracellular matrix enriched in collagen, glycoproteins, and proteoglycans. Pre-clinical studies have validated its compatibility with stromal/stem cells and its ability to support adipogenesis in vitro and in vivo in both small (murine) and large (porcine) subcutaneous implant models. Furthermore, Phase I safety clinical trials have injected decellularized human adipose tissue scaffolds in human volunteers without incident for periods of up to 127 days. This commentary takes an opinionated look at the under-appreciated but potential benefits of obesity as an increasingly available biomaterial resource.

Fat Injection for Cases of Severe Burn Outcomes: A New Perspective of Scar Remodeling and Reduction

BACKGROUND

Despite civilization and progress, burns occur frequently in the world. Remarkable discoveries of wound healing mechanisms have been reported. On the other hand, long-term outcomes from burn injuries represent a barrier to improvement of patients' social, functional, and psychological condition. Lipofilling, described since the 1980s, currently is used for several clinical applications. This study aimed to verify whether lipofilling could ameliorate scar remodeling in three clinical cases.

METHODS

Three adult patients with hemifacial hypertrophic scars and keloids resulting from severe burns 2 to 13 years previously were selected. The patients were treated by injection of adipose tissue harvested from abdominal subcutaneous fat and processed according to Coleman's technique. Two injections (with a 13-month interval between) were administered at the dermohypodermal junction. Histologic examination of scar tissue punch biopsies (hematoxylin-eosin staining) before and after the treatment was performed as well as magnetic resonance scan with contrast.

RESULTS

The clinical appearance and subjective patient feelings after a 6-month follow-up period suggest considerable improvement in the mimic features, skin texture, and thickness. Histologic examination shows patterns of new collagen deposition, local hypervascularity, and dermal hyperplasia in the context of new tissue, with high correspondence to the original.

CONCLUSIONS

The preliminary results show that lipofilling improves scar quality and suggest a tissue regeneration enhancing process.

Autologous adipose-derived stem cells for the treatment of complex cryptoglandular perianal fistula: A randomized clinical trial with long-term follow-up

The aim of this clinical trial (ID Number NCT01803347) was to determine the safety and efficacy of autologous adipose‐derived stem cells (ASCs) for treatment of cryptoglandular fistula. This research was conducted following an analysis of the mistakes of a same previous phase III clinical trial. We designed a multicenter, randomized, single‐blind clinical trial, recruiting 57 patients. Forty‐four patients were categorized as belonging to the intent‐to‐treat group. Of these, 23 patients received 100 million ASCs plus intralesional fibrin glue (group A) and 21 received intralesional fibrin glue (group B), both after a deeper curettage of tracks and closure of internal openings. Fistula healing was defined as complete re‐epithelialization of external openings. Those patients in whom the fistula had not healed after 16 weeks were eligible for retreatment. Patients were evaluated at 1, 4, 16, 36, and 52 weeks and 2 years after treatment. Results were assessed by an evaluator blinded to the type of treatment. After 16 weeks, the healing rate was 30.4% in group A and 42.8% in group B, rising to 55.0% and 63.1%, respectively, at 52 weeks. At the end of the study (2 years after treatment), the healing rate remained at 50.0% in group A and had reduced to 26.3% in group B. The safety of the cellular treatment was confirmed and no impact on fecal continence was detected. The main conclusion was that autologous ASCs for the treatment of cryptoglandular perianal fistula is safe and can favor long‐term and sustained fistula healing.

Biochemical and biomechanical comparisions of decellularized scaffolds derived from porcine subcutaneous and visceral adipose tissue

Decellularized adipose tissue (DAT) is a promising biomaterial for adipose tissue engineering. However, there is a lack of research of DAT prepared from xenogeneic porcine adipose tissue. This study aimed to compare the adipogenic ability of DAT derived from porcine subcutaneous (SDAT) and visceral adipose tissue (VDAT). The retention of key collagen in decellularized matrix was analysed to study the biochemical properties of SDAT and VDAT. For the biomechanical study, both DAT materials were fabricated into three-dimensional (3D) porous scaffolds for rheology and compressive tests. Human adipose-derived stem cells (ADSCs) were cultured on both scaffolds to further investigate the effect of matrix stiffness on cellular morphology and on adipogenic differentiation. ADSCs cultured on soft VDAT exhibited significantly reduced cellular area and upregulated adipogenic markers compared to those cultured on SDAT. In vivo results revealed higher adipose regeneration in the VDAT compared to the SDAT. This study further demonstrated that the relative expression of collagen IV and laminin was significantly higher in VDAT than in SDAT, while the collagen I expression and matrix stiffness of SDAT was significantly higher in comparison to VDAT. This result suggested that porcine adipose tissue could serve as a promising candidate for preparing DAT.

Stem Cell Therapy: A Compassionate Use Program in Perianal Fistula

Aim

To report our experience in a compassionate use program for complex perianal fistula.

Methods

Under controlled circumstances and approved by European and Spanish laws, a compassionate use program allows the use of stem cell therapy for patients with nonhealing diseases, mostly complex fistula-in-ano, who do not meet criteria to be included in a clinical trial. Candidates had previously undergone multiple surgical interventions that had failed. The intervention consisted of surgery (with closure of the internal opening or a surgical flap performance), followed by stem cell injection. Three types of cells were used for implant: stromal vascular fraction, autologous expanded adipose-derived, or allogenic adipose-derived stem cells. Healing was evaluated at 6^th month follow-up. Outcome was classified as partial response or healing. Relapse was evaluated 1 year later. Maximum follow-up period was 48 months.

Results

45 patients (24 male) were included; the mean age was 45 years, which ranged from 24 to 69 years. Since some of them received repeated doses, 52 cases were considered (42 fistula-in-ano, 7 rectovaginal fistulas, 1 urethrorectal fistula, 1 sacral fistula, and 1 hidradenitis suppurativa). Regarding fistula-in-ano, there were 18 Crohn's-associated and 24 cryptoglandular. 49 cases (94.2%) showed partial response starting 6.5 weeks of follow-up. 24 cases (46.2%) healed in a mean time of 5.5 months. A year later, all patients cured remained healed. No adverse effects related to stem cell therapy were reported.

Conclusion

Stem cells are safe and useful for treating anal fistulae. Healing can be achieved in severe cases.

Decellularized biological scaffold and stem cells from autologous human adipose tissue for cartilage tissue engineering

Here, the in vitro engineering of a cartilage-like tissue by using decellularized extracellular matrix scaffold (hECM) seeded with human adipose stem cells (hASCs) which can both be isolated from the human waste adipose tissue is described. Cell-free, highly fibrous and porous hECM was produced using a protocol containing physical (homogenization, centrifugation, molding) and chemical (crosslinking) treatments, characterized by SEM, histochemistry, immunohistochemistry and in vitro cell interaction study. A construct of hECM seeded with hASCs was cultured in chondrogenic medium (with TGF-β3 and BMP-6) for 42 days. SEM and histology showed that the biological scaffold was highly porous and had a compact structure suitable for handling and subsequent cell culture stages. Cells successfully integrated into the scaffold and had good cellular viability and continuity to proliferate. Constructs showed the formation of cartilage-like tissue with the synthesis of cartilage-specific proteins, Collagen type II and Aggrecan. Dimethylmethylene blue dye binding assay demonstrated that the GAG content of the constructs was in tendency to increase with time confirming chondrogenic differentiation of hASCs. The results support that human waste adipose tissue is an important source for decellularized hECM as well as stem cells, and adipose hECM scaffold provides a suitable environment for chondrogenic differentiation of hASCs.

Long-Term Biobanking of Intact Tissue from Lipoaspirate

Autologous fat grafting has now been extensively and successfully performed for more than two decades. Although most adipose grafts and adipose-derived MSC therapies are done with fresh tissue, cryopreservation of tissue allows for much greater flexibility of use. Over the course of five years, 194 cryopreserved adipose samples were thawed and then returned to the collecting physician for subsequent autologous applications. Samples were stored with a mean cryogenic storage time of 9.5 months, with some samples being stored as long as 44 months. The volumes of tissue stored varied from 12 cc to as large as 960 cc. Upon thawing, the volume of recovered whole adipose tissue averaged 67% of the original amount stored for all samples, while the samples that were stored for longer than one year averaged 71%. Recovery was not found to be a function of length of time in cryopreservation. No significant relationship was found between tissue recovery and patient age. While an average recovery of 67% of volume frozen indicates that the use of banked and thawed tissue requires a larger amount of sample to be taken from the patient initially, an experienced clinician easily accomplishes this requirement. As cryopreservation of adipose tissue becomes more commonplace, physicians will find it helpful to know the amount and quality of tissue that will be available after thawing procedures.

Gene activated adipose tissue fragments as advanced autologous biomaterials for bone regeneration: osteogenic differentiation within the tissue and implications for clinical translation

Cost-effective, expedited approaches for bone regeneration are urgently needed in an ageing population. Bone Morphogenetic Proteins (BMPs) stimulate osteogenesis but their efficacy is impeded by their short half-life. Delivery by genetically modified cells can overcome this problem. However, cell isolation and propagation represent significant obstacles for the translation into the clinic. Instead, complete gene activated fragments of adipose tissue hold great potential for bone repair. Here, using an in-vitro culture system, we investigated whether adenoviral transduction with human BMP-2 can promote osteogenic differentiation within adipose tissue fragments. Osteoinduction in adipose tissue fragments was evaluated by quantitative reverse transcriptase polymerase chain reaction, immunohistology and histomorphometry. BMP-2 transduced adipose tissue synthesized BMP-2 protein over 30 days peaking by day six, which significantly promoted osteogenic differentiation as indicated by increased calcium depositions, up-regulation of bone marker genes, and bone-related protein expression. Our results demonstrate that cells within adipose tissue fragments can differentiate osteogenically after BMP-2 transduction of cells on the surface of the adipose tissue. BMP-2 gene activated adipose tissue represents an advanced osteo-regenerative biomaterial that can actively contribute to osteogenesis and potentially enable the development of a novel, cost-effective, one-step surgical approach to bone repair without the need for cell isolation.

Seeding nerve sutures with minced nerve-graft (MINE-G): a simple method to improve nerve regeneration in rats

BACKGROUND

The aim of this study was to assess the effect of seeding the distal nerve suture with nerve fragments in rats.

METHODS

On 20 rats, a 15 mm sciatic nerve defect was reconstructed with a nerve autograft. In the Study Group (10 rats), a minced 1 mm nerve segment was seeded around the nerve suture. In the Control Group (10 rats), a nerve graft alone was used. At 4 and 12 weeks, a walking track analysis with open field test (WTA), hystomorphometry (number of myelinated fibers (n), fiber density (FD) and fiber area (FA) and soleus and gastrocnemius muscle weight ratios (MWR) were evaluated. The Student t-test was used for statistical analysis.

RESULTS

At 4 and 12 weeks the Study Group had a significantly higher n and FD (p = .043 and .033). The SMWR was significantly higher in the Study Group at 12 weeks (p = .0207).

CONCLUSIONS

Seeding the distal nerve suture with nerve fragments increases the number of myelinated fibers, the FD and the SMWR. The technique seems promising and deserves further investigation to clarify the mechanisms involved and its functional effects.

The best surgical strategy for anal fistula based on a network meta-analysis

OBJECTIVE

To determine a superior surgical treatment for anal fistula through a network meta-analysis and to provide the best direction for development in this field.

METHODS

We conducted a systematic literature search of the PubMed, Embase and Cochrane Library databases and extracted data from randomized controlled trials, which compared healing time, incontinence and recurrence associated with surgical strategies for anal fistula. A network meta-analysis was conducted using ADDIS software by evaluating the 3 parameters. Cumulative probability values were utilized to rank the strategies under examination. Inconsistencies were also tested using node-splitting models.

RESULTS

Twenty articles with 1663 patients were included. Fistulotomy plus marsupialisation had the shortest healing time (P = 0.69). Seton placement was the best procedure to avoid postoperative incontinence (P = 0.66). Fistulectomy exhibited the lowest recurrence rate (Probability P = 0.40). In general, fistulotomy plus marsupialisation and surgical ligation plus biomaterial plugging revealed superior clinical efficacy. Node-splitting model testing revealed that no significant inconsistency existed in this research.

CONCLUSIONS

Fistulotomy plus marsupialisation exhibited preliminary superior surgical utility for anal fistula. Additionally, combination of surgical treatment with biomaterials may provide better clinical efficacy. These techniques may warrant consideration for future development in this field.

Adipose‑derived stem cells and hyaluronic acid based gel compatibility, studied in vitro

Minimally invasive aesthetic and cosmetic procedures have increased in popularity. Injectable dermal fillers provide soft tissue augmentation, improve facial rejuvenation and wrinkles, and correct tissue defects. To investigate the use of adipose‑derived stem cells integrated with a hyaluronic acid based gel as a dermal filler, the present study used cytotoxicity studies, proliferation studies, adipogenic and osteogenic differentiation, apoptosis assays and scanning electron microscopy. Although hyaluronic acid induced low levels of apoptosis in adipose‑derived stem cells, its significantly promoted proliferation of adipose‑derived stem cells. Hyaluronic acid demonstrates little toxicity against adipose‑derived stem cells. Adipose‑derived stem cells were able to differentiate into adipocytes and osteoblasts. Furthermore, scanning electron microscopy revealed that adipose‑derived stem cells maintained intact structures on the surface of hyaluronic acid as well as in it, and demonstrated abundant cell attachments. The present study demonstrated the compatibility of adipose‑derived stem cells and hyaluronic acid based gels in vitro.

Tear trough deformity: different types of anatomy and treatment options

Aim

To explore the efficacy of tear trough deformity treatment with the use of hyaluronic acid gel or autologous fat for soft tissue augmentation and fat repositioning via arcus marginalis release.

Material and methods

Seventy-eight patients with the tear trough were divided into three groups. Class I has tear trough without bulging orbital fat or excess of the lower eyelid skin. Class II is associated with mild to moderate orbital fat bulging, without excess of the lower eyelid skin. Class III is associated with severe orbital fat bulging and excess of the lower eyelid skin. Class I or II was treated using hyaluronic acid gel or autologous fat injections. Class III was treated with fat repositioning via arcus marginalis release. The patients with a deep nasojugal groove of class III were treated with injecting autologous fat into the tear trough during fat repositioning lower blepharoplasty as a way of supplementing the volume added by the repositioned fat.

Results

Seventy-eight patients with tear trough deformity were confirmed from photographs taken before and after surgery. There were some complications, but all had complete resolution.

Conclusions

Patients with mild to moderate peri-orbital volume loss without severe orbital fat bulging may be good candidates for hyaluronic acid filler or fat grafting alone. However, patients with more pronounced deformities, severe orbital fat bulging and excess of the lower eyelid skin are often better served by fat repositioning via arcus marginalis release and fat grafting.

Treatment of Crohn's-Related Rectovaginal Fistula With Allogeneic Expanded-Adipose Derived Stem Cells: A Phase I-IIa Clinical Trial

: The aim of this clinical trial was to determine the safety and feasibility of expanded allogeneic adipose-derived stem cells to treat Crohn's-related rectovaginal fistula (CRRVF). We designed a phase I-II clinical trial (https://ClinicalTrials.gov, NCT00999115) to treat 10 patients with CRRVF. Patients receiving biological therapy during follow-up were excluded. Curettage was performed, and a vaginal or rectal flap was added if the surgeon considered it necessary. The therapeutic protocol included intralesional injection of 20 million stem cells in the vaginal walls (submucosal area) and fistula tract. Healing was evaluated 12 weeks later. If the fistula had not healed, a second dose of 40 million stem cells was administered. Patient follow-up was 52 weeks from last cell injection. Healing was defined as re-epithelialization of both vaginal and rectal sides and absence of vaginal drainage. Cytokines and immunological blood tests were monitored. Serious adverse events or rejection issues were not observed. Five patients were excluded because biologic drugs were required to treat a Crohn's disease flare-up during follow-up. Cytokine profiles and immunotoxicity assays showed no statistically significant alterations. Sixty percent of the nonexcluded patients achieved a complete healing. Expanded allogeneic adipose-derived stem-cell injection is a safe and feasible therapy for treating CRRVF, and the healing success rate seems promising (60%). The results of this trial encourage further exploration into this therapy.

SIGNIFICANCE

This may be the first publication in which allogeneic stem cells to treat rectovaginal fistula in Crohn´s disease seem to be a feasible and safe treatment. Additional studies are necessary to confirm the efficacy profile of the allogeneic stem cells strategy in a controlled design.

Cell-Enriched Lipoaspirate Arthroplasty: A Novel Approach to First Carpometacarpal Joint Arthritis

We report a novel, minimal invasive technique for the treatment of symptomatic arthritis of the carpometacarpal (CMC) joint of the thumb, here termed Cell-Enriched Liposaspirate Arthroplasty (CELA). For CELA, autologous fat tissue was harvested using standard liposuction technique followed by an extra-corporal cellular enrichment step. Finally, 1 ml of cell-enriched lipoaspirate was injected into the CMC-joint. Following CELA, the treated patient became pain free within five weeks with a follow-up of 12 months. We conclude that CELA performed on selected cases of arthritis of finger joints such as the basal joint of the thumb has the potential to greatly reduce or delay the necessity for more invasive procedures which tend to improve symptoms of pain at the cost of grip strength and range-of-motion.

Trophic effects of adipose derived stem cells on Langerhans islets viability--Review

Langerhans islets transplantation has been proposed to provide an endogenous source of insulin in Type I diabetes. However, the hypoxic stress and the receptor's immune reaction suffered by the implants cause them to fail in sustaining the insulin production along the time. Experimental studies have shown that adipose derived stem cells (ADSCs) can secrete cytokines that activate free radical scavengers, antioxidants and chaperone heat/shock proteins leading to reduction of apoptosis in damaged tissues. Therefore, using the PubMed database, we reviewed the experimental studies that investigated the trophic effects of ADSCs on Langerhans islets viability, in vitro and in vivo, from 2009 to 2014. We excluded articles that investigated the effects of other types of mesenchymal stem cells on β-cell survival as well articles that worked in the differentiation of ADSCs into insulin producing cells. The analysis of the experiments revealed that exposure of islets to ADSCs in vitro, even for a short period of time, can enhance islet cell viability and function. In vivo studies also corroborated the trophic effects of ADSCs leading to the improvement of islet function and reduction of the number of the islets required for controlling the receptor's glucose levels. This review can contribute to guide future experiments looking for a long term diabetes treatment employing ADSC trophic effects for the enhancement of transplanted Langerhans islet viability and functioning.

Effects of erythropoietin on adipose tissue: a possible strategy in refilling

Background:

The increased resorption and the difficulty of the fat graft take following autologous fat transplantation procedure are associated with reduced fat tissue revascularization and increased apoptosis of adipose cells. We suppose that the lipofilling procedure induces an inflammatory environment within the fat graft mass, whose evolution influences the efficacy of autologous fat graft survival. Erythropoietin (EPO) is a glycoprotein hormone known to exert angiogenetic and anti-inflammatory effects; therefore, our purpose was to investigate its reaction with adipose tissue used in lipofilling.

Methods:

Fat masses were harvested using manual suction lipectomy and then seeded on dishes in appropriate culture and treated for 3 weeks with 3 doses of EPO. CD31 and CD68 immunohistochemistry was used to identify microvessels and several infiltrating leukocyte cells.

Results:

Following EPO administration, we have detected an increase in the number of CD31-positive microvessel endothelium cells and CD31-positive small leukocytes and a reduction of CD68-positive cells. These effects were more conspicuous following higher EPO dose.

Conclusions:

Our findings evidence EPO treatment as a useful strategy to sustain the revascularization of grafted tissue and to reduce its inflammatory state.

Fat grafting: a citation analysis of the seminal articles

Background:

There has been substantial rise in the volume of published works on fat transfer in the medical literature in the past 25 years, and this is indicative of its growing popularity. However, many unanswered questions remain, and there is no consensus as to the optimum technique. Consequently, the scientific and clinical research on fat grafting continues to increase rapidly. The purpose of our study was to perform a bibliometric analysis of the most-cited articles in fat transfer.

Methods:

Through the Web of Science, all articles relating to fat grafting were identified in the plastic and reconstructive literature. The 100 most-cited articles were identified and analyzed individually.

Results:

Total citations ranged from 35 to 363 and the most-cited paper by Sidney Coleman was published in Plastic and Reconstructive Surgery. The United States produced 46% of the most-cited papers, and the University of California was the most prolific institution. Twenty-one articles focused on lipofilling to the face while 14 articles looked at fat grafting to the breast.

Conclusions:

The scientific relevance of a published work is reflected in the number of citations from peers that it receives. Therefore, the 100 most-cited papers in fat grafting have been the most influential articles on this field, and they are likely to be the ones that are remembered most.

Measurement of the biophysical properties of porcine adipose-derived stem cells by a microperfusion system

Adipose-derived stem cells (ADSCs), which are an accessible source of adult stem cells with capacities for self-renewal and differentiation into various cell types, have a promising potential in tissue engineering and regenerative medicine strategies. To meet the clinical demand for ADSCs, cryopreservation has been applied for long-term ADSC preservation. To optimize the addition, removal, freezing, and thawing of cryoprotective agents (CPAs) applied to ADSCs, we measured the transport properties of porcine ADSCs (pADSCs). The cell responses of pADSCs to hypertonic phosphate-buffered saline and common CPAs, dimethyl sulfoxide, ethylene glycol, and glycerol were measured by a microperfusion system at temperatures of 28, 18, 8, and -2°C. We determined the osmotically inactive cell volume (Vb), hydraulic conductivity (Lp), and CPA permeability (Ps) at various temperatures in a two-parameter model. Then, we quantitatively analyzed the effect of temperature on the transport properties of the pADSC membrane. Biophysical parameters were used to optimize CPA addition, removal, and freezing processes to minimize excessive shrinkage of pADSCs during cryopreservation. The biophysical properties of pADSCs have a great potential for effective optimization of cryopreservation procedures.

Pedicled buccal fat pad flap as a reliable surgical strategy for the treatment of medication-related osteonecrosis of the jaw

PURPOSE

The purpose of this study was to evaluate the coverage of the pedicled buccal fat pad flap (PBFP) and the long-term results of this treatment in patients with medication-related osteonecrosis of the jaw (MRONJ).

PATIENTS AND METHODS

Ten patients (2 men and 8 women; average age, 72.9 yr old) diagnosed with MRONJ were selected. Patients were treated with a PBFP. Data from patients regarding MRONJ stage, defect size, bone exposure after surgery, operation time, admission period, duration of antibiotic therapy, recurrence of disease, and postoperative complications were analyzed retrospectively.

RESULTS

Six patients were diagnosed with MRONJ stage 2, and 4 patients were diagnosed with MRONJ stage 3. The maximum defect in the study was 62 × 18 mm. Among the 10 patients, there was only 1 bony exposure, which occurred on postoperative day 2 after receiving the PBFP. This exposure might have been due to an incomplete resection of the affected bone. There were no severe donor site morbidities, and all patients showed satisfactory healing without incident.

CONCLUSIONS

According to this evaluation, the PBFP effectively covered a relatively large surgical defect. Complications were minimal, and there was no recurrence of bony exposure during follow-up. In conclusion, using the PBFP was a reliable treatment option for the management of denuded bone in patients with MRONJ.

Autologous fat grafting: in search of the optimal technique

OBJECTIVE

Recent advances in adipose cellular biology have repopularized autologous fat grafting as a method widely used in both reconstructive and aesthetic surgery. This review aims to summarize our current knowledge on autologous fat grafting emphasizing harvesting techniques and processing methods as well as current trends and approaches.

METHODS

A thorough search of earlier and recent literature until October 2013 was conducted using the terms autologous fat grafting, autologous fat transfer, lipoaspirate, lipoinjection, fat harvest, and lipotransfer in PubMed and ClinicalTrials.gov databases, and relevant English- and German-language articles were included.

RESULTS

Findings were categorized in a step-by-step approach of the fat grafting procedure into indications, selection of donor site, techniques for harvesting, processing, and reimplantation of autologous fat.

CONCLUSIONS

Further in-depth knowledge will provide definite answers on fat graft survival; demonstrate safe methods to increase cell viability, grafting outcome predictability; and reliability; enhance safety; and strengthen the scientific and clinical establishment of this increasingly promising method.

In situ tissue regeneration through host stem cell recruitment

The field of tissue engineering has made steady progress in translating various tissue applications. Although the classical tissue engineering strategy, which involves the use of culture-expanded cells and scaffolds to produce a tissue construct for implantation, has been validated, this approach involves extensive cell expansion steps, requiring a lot of time and laborious effort before implantation. To bypass this ex vivo process, a new approach has been introduced. In situ tissue regeneration utilizes the body's own regenerating capacity by mobilizing host endogenous stem cells or tissue-specific progenitor cells to the site of injury. This approach relies on development of a target-specific biomaterial scaffolding system that can effectively control the host microenvironment and mobilize host stem/progenitor cells to target tissues. An appropriate microenvironment provided by implanted scaffolds would facilitate recruitment of host cells that can be guided to regenerating structural and functional tissues.

Effect of ASCs on the graft survival rates of fat particles in rabbits

This study was conducted to explore the effect of adipose-derived stem cells (ASCs) on the graft survival rates of fat particles in rabbits. Six domestic rabbits were used for a 3-month study; 1.4 grams of fat tissues were harvested from the bilateral inguinal regions of each animal. They were cut into granules and divided into three parts (A = 0.4 g, B = 0.4 g, and C = 0.6 g). Part A was centrifuged after 0.075% collagenase digestion for isolation of the stromal vascular fraction (SVF). About 0.2 grams of SVF containing ASCs was obtained, and then incorporated with part B to create a treated group, whereas part C was treated as a control group. The tissues in both groups were randomly transplanted into a subcutaneous space that had been created on each side of the dorsal midline of the rabbit. The grafts were taken out after 3 months for calculation of the survival rates. The graft survival rate in the treated group was 23.56 ± 2.49%, while that in the control group was 11.06 ± 2.10%. The graft survival rate in the treated group increased significantly, compared with in the control group (p < 0.01). Improved transplantation effects may be obtained by implanting the fat particles mixed with ASCs. It is suggested that this approach has the potential for becoming a new method of fat graft in clinical practice.

Engraftment of human adipose derived stem cells delivered in a hyaluronic acid preparation in mice

PURPOSE

To evaluate the implant of human adipose derived stem cells (ADSC) delivered in hyaluronic acid gel (HA), injected in the subcutaneous of athymic mice.

METHODS

Control implants -HA plus culture media was injected in the subcutaneous of the left sub scapular area of 12 athymic mice. ADSC implants: HA plus ADSC suspended in culture media was injected in the subcutaneous, at the contra lateral area, of the same animals. With eight weeks, animals were sacrificed and the recovered implants were processed for extraction of genomic DNA, and histological study by hematoxilin-eosin staining and immunufluorescence using anti human vimentin and anti von Willebrand factor antibodies.

RESULTS

CONTROLS

Not visualized at the injection site. An amorphous substance was observed in hematoxilin-eosin stained sections. Human vimentin and anti von Willebrand factor were not detected. No human DNA was detected. ADSC implants - A plug was visible at the site of injection. Fusiform cells were observed in sections stained by hematoxilin- eosin and both human vimentin and anti von Willebrand factor were detected by immunofluorescence. The presence of human DNA was confirmed.

CONCLUSION

The delivery of human adipose derived stem cells in preparations of hyaluronic acid assured cells engraftment at the site of injection.

Adipose Tissue-Derived Mesenchymal Cells Support Skin Reepithelialization through Secretion of KGF-1 and PDGF-BB: Comparison with Dermal Fibroblasts

Epidermal organization and homeostasis are regulated by mesenchymal influences through paracrine actions. Until today, dermal fibroblasts (DFs) are used in the “dermal” layer to support keratinocyte growth in vitro in dermal and skin substitutes. In the present work, we used human adipose tissue-derived mesenchymal cells (ADMCs) as a support of keratinocyte growth in vitro (in monolayer culture and in 3D skin cell culture models) and in vivo (mouse wound healing models) and compared our findings with those obtained using dermal fibroblasts. ADMCs induce reepithelialization during wound healing more efficiently than DFs, by enhancing keratinocyte proliferation through cell cycle progression, and migration. This effect is mediated (at least partially) by a paracrine action of KGF-1 and PDGF-BB, which are more prominently expressed in ADMCs than in DFs. Furthermore, replacement of DFs by ADMCs in the dermal compartment of organotypic skin cultures leads to an artificial epidermis resembling to that of normal skin, concerning the general histology, although with a higher expression of cytokeratins 5 and 19. In Rag1 knockout mice, ADMCs induced a more rapid reepithelialization and a more effective wound healing, compared to dermal fibroblasts. In conclusion, we provide evidence that ADMCs can serve as supportive cells for primary keratinocyte cultures. In addition, because of their abundance and the great cell yield achieved during ADMC isolation, they represent an interesting cell source, with potential aspects for clinical use.

Cryopreservation of adipose tissue

The main obstacle to achieving favorable outcome of soft-tissue augmentation after autologous fat transplantation is unpredictable long-term results due to the high rate of absorption in the grafted site. At the present time, adipose aspirates can only be used for immediate autologous fat grafting during the same procedure in which liposuction is performed; therefore adipose aspirates obtained from the procedure are usually discarded. it has been a strong desire of both surgeons and patients to be able to preserve the adipose aspirates, if an optimal technique were available, for potential future applications. For the last several years, cryopreservation of adipose tissue has been studied extensively in the author's laboratory. Several findings from this exciting translational research will lead to develop a reliable method for long-term preservation of adipose tissue in the future. in addition, successful long-term preservation of adipose tissue may open a new era in adipose tissue related tissue regeneration.

Adipose tissue engineering with cells in engineered matrices

Tissue engineering has shown promise for the development of constructs to facilitate large volume soft tissue augmentation in reconstructive and cosmetic plastic surgery. This article reviews the key progress to date in the field of adipose tissue engineering. In order to effectively design a soft tissue substitute, it is critical to understand the native tissue environment and function. As such, the basic physiology of adipose tissue is described and the process of adipogenesis is discussed. In this article, we have focused on tissue engineering using a cell-seeded scaffold approach, where engineered extracellular matrix substitutes are seeded with exogenous cells that may contribute to the regenerative response. The strengths and limitations of each of the possible cell sources for adipose tissue engineering, including adipose-derived stem cells, are detailed. We briefly highlight some of the results from the major studies to date, involving a range of synthetic and naturally derived scaffolds. While these studies have shown that adipose tissue regeneration is possible, more research is required to develop optimized constructs that will facilitate safe, predictable and long-term augmentation in clinical applications.

Decellularized extracellular matrix derived from porcine adipose tissue as a xenogeneic biomaterial for tissue engineering

Cells in tissues are surrounded by the extracellular matrix (ECM), a gel-like material of proteins and polysaccharides that are synthesized and secreted by cells. Here we propose that the ECM can be isolated from porcine adipose tissue and holds great promise as a xenogeneic biomaterial for tissue engineering and regenerative medicine. Porcine adipose tissue is easily obtained in large quantities from commonly discarded food waste. Decellularization protocols have been developed for extracting an intact ECM while effectively eliminating xenogeneic epitopes and minimally disrupting the ECM composition. Porcine adipose tissue was defatted by homogenization and centrifugation. It was then decellularized via chemical (1.5 M sodium chloride and 0.5% sodium dodecyl sulfate) and enzymatic treatments (DNase and RNase) with temperature control. After decellularization, immunogenic components such as nucleic acids and α-Gal were significantly reduced. However, abundant ECM components, such as collagen (332.9±12.1 μg/mg ECM dry weight), sulfated glycosaminoglycan (GAG, 85±0.7 μg/mg ECM dry weight), and elastin (152.6±4.5 μg/mg ECM dry weight), were well preserved in the decellularized material. The biochemical and mechanical features of a decellularized ECM supported the adhesion and growth of human cells in vitro. Moreover, the decellularized ECM exhibited biocompatibility, long-term stability, and bioinductivity in vivo. The overall results suggest that the decellularized ECM derived from porcine adipose tissue could be useful as an alternative biomaterial for xenograft tissue engineering.

Autologous expanded adipose-derived stem cells for the treatment of complex cryptoglandular perianal fistulas: a phase III randomized clinical trial (FATT 1: fistula Advanced Therapy Trial 1) and long-term evaluation

BACKGROUND

Autologous adipose-derived stem cells may represent a novel approach for the management of complex fistula-in-ano. After successful phase I and II clinical trials, a phase III trial was performed to investigate the safety and efficacy.

DESIGN

In this multicenter, randomized, single-blind, add-on clinical trial, 200 adult patients from 19 centers were randomly assigned to receive 20 million stem cells (group A, 64 patients), 20 million adipose-derived stem cells plus fibrin glue (group B, 60 patients), or fibrin glue (group C, 59 patients) after closure of the internal opening. Fistula healing was defined as reepithelization of the external opening and absence of collection >2 cm by MRI. If the fistula had not healed at 12 weeks, a second dose (40 million stem cells in groups A and B) was administered. Patients were evaluated at 24 to 26 weeks (primary end point) and at 1 year (long-term follow-up).

RESULTS

All results are according to the "blinded evaluator" assessment. After 24 to 26 weeks, the healing rate was 39.1%, 43.3%, 37.3% in groups A, B, and C (p = 0.79). At 1 year, the healing rates were 57.1%, 52.4%, and 37.3 % (p = 0.13). On analysis of the subpopulation treated at the technique's pioneer center, healing rates were 54.55%, 83.33%, and 18.18%, at 24 to 26 weeks (p < 0.001). No SAEs were reported.

CONCLUSIONS

In treatment of complex fistula-in-ano, a dose of 20 or 60 million adipose-derived stem cells alone or in combination with fibrin glue was considered a safe treatment, achieving healing rates of approximately 40% at 6 months and of more than 50% at 1-year follow-up. It was equivalent to fibrin glue alone. No statistically significant differences were found when the 3 groups where compared.

CLINICAL TRIALS REGISTRATION

www.clinicaltrials.gov, identifier NCT00475410; Sponsor, Cellerix SA.

Effects of FGF-2 on human adipose tissue derived adult stem cells morphology and chondrogenesis enhancement in Transwell culture

Injured cartilage is difficult to repair due to its poor vascularisation. Cell based therapies may serve as tools to more effectively regenerate defective cartilage. Both adult mesenchymal stem cells (MSCs) and human adipose derived stem cells (hADSCs) are regarded as potential stem cell sources able to generate functional cartilage for cell transplantation. Growth factors, in particular the TGF-b superfamily, influence many processes during cartilage formation, including cell proliferation, extracellular matrix synthesis, maintenance of the differentiated phenotype, and induction of MSCs towards chondrogenesis. In the current study, we investigated the effects of FGF-2 on hADSC morphology and chondrogenesis in Transwell culture. hADSCs were obtained from patients undergoing elective surgery, and then cultured in expansion medium alone or in the presence of FGF-2 (10 ng/ml). mRNA expression levels of SOX-9, aggrecan and collagen type II and type X were quantified by real-time polymerase chain reaction. The morphology, doubling time, trypsinization time and chondrogenesis of hADSCs were also studied. Expression levels of SOX-9, collagen type II, and aggrecan were all significantly increased in hADSCs expanded in presence of FGF-2. Furthermore FGF-2 induced a slender morphology, whereas doubling time and trypsinization time decreased. Our results suggest that FGF-2 induces hADSCs chondrogenesis in Transwell culture, which may be beneficial in cartilage tissue engineering.

Nerve regeneration with aid of nanotechnology and cellular engineering

Repairing nerve defects with large gaps remains one of the most operative challenges for surgeons. Incomplete recovery from peripheral nerve injuries can produce a diversity of negative outcomes, including numbness, impairment of sensory or motor function, possibility of developing chronic pain, and devastating permanent disability. In the last few years, numerous microsurgical techniques, such as coaptation, nerve autograft, and different biological or polymeric nerve conduits, have been developed to reconstruct a long segment of damaged peripheral nerve. A few of these techniques are promising and have become popular among surgeons. Advancements in the field of tissue engineering have led to development of synthetic nerve conduits as an alternative for the nerve autograft technique, which is the current practice to bridge nerve defects with gaps larger than 30 mm. However, to date, despite significant progress in this field, no material has been found to be an ideal alternative to the nerve autograft. This article briefly reviews major up-to-date published studies using different materials as an alternative to the nerve autograft to bridge peripheral nerve gaps in an attempt to assess their ability to support and enhance nerve regeneration and their prospective drawbacks, and also highlights the promising hope for nerve regeneration with the next generation of nerve conduits, which has been significantly enhanced with the tissue engineering approach, especially with the aid of nanotechnology in development of the three-dimensional scaffold. The goal is to determine potential alternatives for nerve regeneration and repair that are simply and directly applicable in clinical conditions.

Current status and future development of cell transplantation therapy for periodontal tissue regeneration

It has been shown that stem cell transplantation can regenerate periodontal tissue, and several clinical trials involving transplantation of stem cells into human patients have already begun or are in preparation. However, stem cell transplantation therapy is a new technology, and the events following transplantation are poorly understood. Several studies have reported side effects and potential risks associated with stem cell transplantation therapy. To protect patients from such risks, governments have placed regulations on stem cell transplantation therapies. It is important for the clinicians to understand the relevant risks and governmental regulations. This paper describes the ongoing clinical studies, basic research, risks, and governmental controls related to stem cell transplantation therapy. Then, one clinical study is introduced as an example of a government-approved periodontal cell transplantation therapy.

Revitalization of cortical bone allograft by application of vascularized scaffolds seeded with osteogenic induced adipose tissue derived stem cells in a rabbit model

BACKGROUND

Adipogenous tissue derived stem cells (ASC) are available in abundance in the human body and can differentiate in the presence of lineage-specific induction factors, for example, in myogenic, adipogenic, chondrogenic and osteogenic cells. The aim of this study was to evaluate the impact of osteogenic induced ASC's (O-ASC) on revascularization and cellular repopulation of avital cortical bone employing a vascularized bovine scaffold.

METHODS

An inguinal arterio-venous bundle was dissected in the groin of female white New Zealand rabbits (n = 6) and placed centrally inside an O-ASC seeded scaffold via a central drill hole. In the same surgical session this construct was placed into a segment of avital cortical bone allograft from a donor rabbit. Unseeded scaffolds that were implanted and treated in the same fashion served as controls (n = 6). In order to prevent external revascularization, all constructs were wrapped in silicon foil and finally implanted in the rabbits' groin. Three months later, the constructs were explanted and investigated for vascularization of (a) the scaffold (b) the surrounding bone allograft. Histological stainings to determine cell growth, cellular repopulation of the scaffold and the cortical bone matrix, as well as inflammatory parameters were carried out.

RESULTS

O-ASC seeded scaffolds showed a significant increase in new vessel formation in the scaffold as well as in the bone allograft compared to unseeded scaffolds. Furthermore, new vital osteocytes as a sign of cellular repopulation inside the bone allograft were found only in the treatment group. Vital chondrocytes were only found in the O-ASC seeded scaffolds as well.

CONCLUSION

The presence of O-ASC significantly induce neo-vascularization and osteocytic repopulation of previously avital bone allograft as opposed to unseeded scaffolds in a rabbit model. Hence, this model might be of relevant value for future bone tissue engineering research and for re-vitalizing marginally nourished bone such as in avascular bone necrosis.

Fat grafting accelerates revascularisation and decreases fibrosis following thermal injury

BACKGROUND

Fat grafting has been shown clinically to improve the quality of burn scars. To date, no study has explored the mechanism of this effect. We aimed to do so by combining our murine model of fat grafting with a previously described murine model of thermal injury.

METHODS

Wild-type FVB mice (n=20) were anaesthetised, shaved and depilitated. Brass rods were heated to 100°C in a hot water bath before being applied to the dorsum of the mice for 10s, yielding a full-thickness injury. Following a 2-week recovery period, the mice underwent Doppler scanning before being fat/sham grafted with 1.5cc of human fat/saline. Half were sacrificed 4 weeks following grafting, and half were sacrificed 8 weeks following grafting. Both groups underwent repeat Doppler scanning immediately prior to sacrifice. Burn scar samples were taken following sacrifice at both time points for protein quantification, CD31 staining and Picrosirius red staining.

RESULTS

Doppler scanning demonstrated significantly greater flux in fat-grafted animals than saline-grafted animals at 4 weeks (fat=305±15.77mV, saline=242±15.83mV; p=0.026). Enzyme-linked immunosorbent assay (ELISA) analysis in fat-grafted animals demonstrated significant increase in vasculogenic proteins at 4 weeks (vascular endothelial growth factor (VEGF): fat=74.3±4.39ngml(-1), saline=34.3±5.23ngml(-1); p=0.004) (stromal cell-derived factor-1 (SDF-1): fat=51.8±1.23ngml(-1), saline grafted=10.2±3.22ngml(-1); p<0.001) and significant decreases in fibrotic markers at 8 weeks (transforming growth factor-ß1(TGF-ß): saline=9.30±0.93, fat=4.63±0.38ngml(-1); p=0.002) (matrix metallopeptidase 9 (MMP9): saline=13.05±1.21ngml(-1), fat=6.83±1.39ngml(-1); p=0.010). CD31 staining demonstrated significantly up-regulated vascularity at 4 weeks in fat-grafted animals (fat=30.8±3.39 vessels per high power field (hpf), saline=20.0±0.91 vessels per high power field (hpf); p=0.029). Sirius red staining demonstrated significantly reduced scar index in fat-grafted animals at 8 weeks (fat=0.69±0.10, saline=2.03±0.53; p=0.046).

CONCLUSIONS

Fat grafting resulted in more rapid revascularisation at the burn site as measured by laser Doppler flow, CD31 staining and chemical markers of angiogenesis. In turn, this resulted in decreased fibrosis as measured by Sirius red staining and chemical markers.

The effect of serial passaging on the proliferation and differentiation of bovine adipose-derived stem cells

Adipose-derived stem cells (ASCs) represent an excellent cell source for the development of regenerative therapies for a broad variety of tissue disorders. Commonly, in vitro expansion is necessary to obtain sufficient cell populations for research purposes and clinical applications. Although it has been demonstrated that human ASCs can maintain their adipogenic, chondrogenic and osteogenic potential in long-term culture (up to 15 passages), it is not guaranteed that a satisfactory level of differentiation is achievable in later passages. In this study, we investigated the self-renewal and multilineage differentiation capacity of bovine ASCs, isolated from the interdigital fat pad, and explored how serial passaging influences the cells. A proliferation study examined the changes in growth kinetics from passage 1 to 5, and multilineage (adipogenesis, chondrogenesis and osteogenesis) differentiation studies were conducted to compare the potential between passage 2 (P2) and passage 5 (P5). From the proliferation study, a statistically significant change in the doubling time did not appear until P5. In the differentiation study, both P2 and P5 ASCs could be stimulated to undergo multilineage differentiation under specific culturing conditions. However, adipogenic and chondrogenic cultures showed significantly lower levels of differentiation in the P5-induced cultures. In contrast, P5-induced osteogenic cultures had higher alkaline phosphatase enzyme activity than P2-induced cultures, suggesting an increase in the osteogenic response with serial passaging. Overall, bovine ASCs are capable of self-renewal and multilineage differentiation; however, long-term in vitro expansion has a negative effect on adipogenic and chondrogenic differentiation, while potentially favoring osteogenesis.

Lipofilling with minimal access cranial suspension lifting for enhanced rejuvenation

BACKGROUND

Loss of volume is an important aspect in facial aging, but its relevance is frequently neglected during treatment.

OBJECTIVES

The authors discuss lipofilling as an ancillary procedure to improve the impact of facelifting procedures.

METHODS

Fifty patients who underwent minimal access cranial suspension (MACS) lifting alone were retrospectively analyzed, and their results were compared to 42 retrospective cases of MACS lifting with adjuvant lipofilling. The results were evaluated with a photographic ranking system by two panels (five plastic surgeons and five medical students).

RESULTS

Combined MACS lifting and lipofilling yielded overall cosmetic results that were significantly better than the results achieved with MACS lifting alone. Photographic evaluations showed that improvements were more pronounced in the tear trough (P < .05) and malar eminence (P < .01) than in the nasolabial groove (P > .05).

CONCLUSIONS

Volume restoration with lipofilling following MACS lifting procedures produces significantly better postoperative results than MACS lifting alone. This combined procedure produces the most dramatic improvements in the tear trough and malar eminence regions.

Staged reconstruction of the lower eyelid following tri-lamellar injury: a case series and anatomic study

PURPOSE

Lower eyelid scaring and malposition following violation of all three lamellae pose a significant ophthalmologic reconstructive challenge. The purpose of our study was to document a staged approach for this problem using: 1) transconjunctival scar release followed by palatal graft below the tarsal plate and subciliary scar release followed by full-thickness skin graft superficial to the tarsal plate and 2) subsequent autologous fat grafting to the lower eyelid.

METHODS

Cadaveric anatomic dissections were performed. Post-traumatic and post-surgical lower eyelid deformities requiring reconstruction were reviewed and outcome assessment was based on symptomatic improvement, perioperative complications, reoperations and long-term follow-up (> 1 year).

RESULTS

Cadaver dissections demonstrated consistent lower eyelid tarsal plate and lamellar anatomy for the use of palatal graft and skin grafting. Clinically, 75% cases resulted from full thickness traumatic laceration of the lower eyelid or malar region and 25% of cases occurred after transconjunctival incisions were made for zygomatic maxillary repositioning following partial lower eyelid laceration. Preoperative symptoms of: epiphora, tearing, redness, blurry vision and dryness improved in all patients and complete resolution was seen in 63% of patients. Thirty-seven percent of patients had complications: Redundancy of palatal graft, Partial FTSG loss, cellulitis after fat transfer.

CONCLUSIONS

We describe an approach for the scarred and displaced lower eyelid following injury to all three lamellae that provided symptomatic improvement after lower lid scar tissue release, lengthening of the contracted septum, support of the posterior lamellae with a palatal graft and a replacement of anterior lamella with full thickness skin graft.

[Liposuction]

Liposuction is one of the most commonly performed procedures in aesthetic surgery. The primary aim is body contouring and not weight reduction. The vast amount of available methods for suctioning subcutaneous fat allows an optimal individual treatment plan, keeping in mind the correct indications. Although liposuction is often offered as a minor and harmless surgery, it is a complex procedure. A thorough training of the surgeon and in-depth knowledge about possible complications is essential. In addition to aesthetic indications liposuction is also a valuable tool in reconstructive surgery. For optimal patient selection the skin elasticity has to be considered during the preoperative assessment. Besides pure volume reduction through liposuction, the regenerative possibilities of adipose tissue are of great interest for basic research and clinical applications. Lipofilling or autologous fat transfer is used for a wide variety of aesthetic and reconstructive procedures. Of special interest is the regenerative and reconstructive potential of adipose-derived stem cells (ADSC).

Decellularized extracellular matrix derived from human adipose tissue as a potential scaffold for allograft tissue engineering

Decellularized tissues composed of extracellular matrix (ECM) have been clinically used to support the regeneration of various human tissues and organs. Most decellularized tissues so far have been derived from animals or cadavers. Therefore, despite the many advantages of decellularized tissue, there are concerns about the potential for immunogenicity and the possible presence of infectious agents. Herein, we present a biomaterial composed of ECM derived from human adipose tissue, the most prevalent, expendable, and safely harvested tissue in the human body. The ECM was extracted by successive physical, chemical, and enzymatic treatments of human adipose tissue isolated by liposuction. Cellular components including nucleic acids were effectively removed without significant disruption of the morphology or structure of the ECM. Major ECM components were quantified, including acid/pepsin-soluble collagen, sulfated glycosaminoglycan (GAG), and soluble elastin. In an in vivo experiment using mice, the decellularized ECM graft exhibited good compatibility to surrounding tissues. Overall results suggest that the decellularized ECM containing biological and chemical cues of native human ECM could be an ideal scaffold material not only for autologous but also for allograft tissue engineering.