Autologous Tissue Transplantation Research Articles

Behavior of adipocytes in the mammary niche during pregnancy and lactation

Primarily, the adipose tissue is known for its function storing excess energy as fat. This tissue is also an endocrine organ and communicates with several tissues, such as muscle, liver and brain. In addition, the adipose tissue is an accessible source of adult stem cells. Autologous adipose tissue transplant used for plastic surgery purposes take advantage of this feature. These pluripotent cells are also targets for gene therapy and autologous transplant in regenerative medicine. A recent study using state-of-art technology explores the plasticity within mature adipocyte into stroma of the mammary gland. Strikingly, adipocyte-derived preadipocytes de-differentiate and re-differentiate repeatedly, during pregnancy to accommodate the new imposed body metabolic demand. The emerging knowledge from this study is essential to understand the cellular processes occurring into the mammary gland during pregnancy, lactation, and involution. This idea opens new perspectives to study the involvement of the adipose tissue in systemic regulatory processes during these transitional states and has implication on conditions as cancer and inflammation-related diseases.

THE POSSIBILITIES OF MAMMOPLASTY USING THE TRANSPLANTATION OF AUTOLOGOUS ADIPOSE TISSUE ENRICHED WITH STEM CELLS

The information given in the scientific literature sources about the transplantation of autologous adipose tissue (AAT) enriched with stem cells (SC) in cases of breast shape and volume correction (in both aesthetic indications and elimination of postoperative deformities) is characterized by versatile results. This circumstance promotes the purposeful study about the possibilities of modern surgical technologies in use of mesenchymal SC (MSCs) of autologous adipose tissue in cases of mammoplasty. The information on the basic techniques of mesenchymal SC isolation from the AAT has been analyzed. The data of cytological criteria were studied separately that allow to relate this biological substance to the SC. Technical features of stem cells transplantation derived from the autologous adipose transplant in cases of mammoplasty are demonstrated. According to opinion among the competent researchers, elimination of postoperative deformities using cellular technologies is a promising scientific direction of medicine.

Fetal subcutaneous cells have potential for autologous tissue engineering.

Major congenital malformations affect up to 3% of newborns. Infants with prenatally diagnosed soft tissue defects should benefit from having autologous tissue readily available for surgical implantation in the perinatal period. In this study, we investigate fetal subcutaneous cells as cellular source for tissue engineering. Fetal subcutaneous biopsies were collected from elective terminations at gestational Week 20-21. Cells were isolated, expanded, and characterized in vitro. To determine cell coverage, localization, viability, and proliferation in different constructs, the cells were seeded onto a matrix (small intestine submucosa) or in collagen gel with or without poly(ε-caprolactone) mesh and were kept in culture for up to 8weeks before analysis. Angiogenesis was analysed through a tube-forming assay. Fetal subcutaneous cells could be expanded until 43±3 population doublings, expressed mesenchymal markers, and readily differentiate into adipogenic and osteogenic lineages. The cells showed low adherence to small intestine submucosa and did not migrate deep into the matrix. However, in collagen gels, the cells migrated into the gel and proliferated with sustained viability for up to 8weeks. The cells in the matrices expressed Ki67, CD73, and α-smooth muscle actin but not cytokeratin or CD31. Fetal cells derived from subcutaneous tissue demonstrated favourable characteristics for preparation of autologous tissue transplants before birth. Our study supports the theory that cells could be obtained from the fetus during pregnancy for tissue engineering purposes after birth. In a future clinical situation, autologous transplants could be used for reconstructive surgery in severe congenital malformations.

151 Use of Autologous Dermal Tissue Preserves Sexual Function after Pelvic Organ Prolapse Surgery

Established surgical methods for pelvic organ prolapse include use of tension-free vaginal mesh and laparoscopic sacrocopopexy. However, an alert by the US Food and Drug Administration has increased patient anxiety about foreign body insertion. We developed a method of autologous dermal tissue transplantation for treatment of pelvic organ prolapse. This technique improves operative safety and effectiveness and preserves sexual function. Because blood flow is supplied from the uterine and mucosal sides of the bladder, and the engraftment rate is high. To evaluate the safety and effectiveness of using autologous dermal tissue for surgical repair of pelvic organ prolapse. The procedure was performed by adding dermal transplantation to cystocele/uterine prolapse surgery, which does not use conventional mesh, under general anesthesia. First, we resected the epidermis of abdominal skin and defatted the dermis. Next, the mucosa of the vaginal posterior wall was longitudinally dissected, and 2-0 TiCron (nonabsorbable suture) was applied to the left and right sacrospinous ligament (two stitches a side; four stitches in total). A vertical incision was made in the anterior vaginal wall, and 2-0 TiCron was stitched to each side of the arcus tendineus fascia pelvis (two stitches in total). The bladder was sutured with a 3-0 Vicryl three-needle horizontal mattress suture. The dermis was implanted on the bladder and anterior wall of the cervix and was placed on the sacrospinous ligament and the arcus tendineus fascia pelvis. The posterior wall of the uterine cervix was lifted to the sacrospinous ligament. The patient was discharged on the fifth day after surgery and used an external pessary (FemiCushion) for 2 months postoperatively, until the graft was firmly engrafted. This external pessary supports the pelvic floor muscle and can be used before surgery after removing a vaginal pessary, thereby improving patient quality of life. Patients can also use the external pessary if they develop sexual dysfunction while using a vaginal pessary.

Orthoplastic extremity reconstruction – From replantation to transplantation

For more than a half century, the use of the operating microscope for extremity surgery has led to remarkable advances in the management of orthopaedic trauma, tumours, infections and congenital differences. The microsurgical reconstructive ladder ascends from basic microsurgical procedures such as digital artery or nerve repair, to more complex procedures such as autologous tissue transplantation (free tissue transfer). Tissue transfers have also become more sophisticated with the evolution from simple myocutaneous flaps to perforator-based flaps. Functional muscle transfers, toe-to-hand transfers, and recently vascularised composite allotransplantation make up the highest rungs on this ladder. The development of the orthoplastic approach simultaneously integrates principles and practices of both orthopaedic surgery and plastic surgery for optimal care of extremities based heavily on the application of microsurgical techniques. We will describe our contributions and innovations in orthopaedic clinical practice using microsurgical techniques as well as highlight our clinical, anatomic and basic science research in reconstructive microsurgery that have led to improvements in limb salvage, reconstruction and restoration during the last 25 years.

Harnessing Endogenous Cellular Mechanisms for Bone Repair.

Although autologous tissue transplantation represents a valid approach for bone repair, it has encountered crucial barriers in therapeutic translation, not least the invasive process necessary for stem cell isolation. In recent years, the scientific community has made significant strides for identifying new treatment options, and great emphasis has been placed on the tight interaction between skeletal and immune system in modulating the outcome of bone repair. Within the context of specific injury environmental cues, the cross talk among inflammatory cells and tissue resident and/or circulating progenitor cells is crucial to finely coordinate repair and remodeling processes. The appropriate modulation of the inflammatory response can now be considered a new trend in the field of regenerative medicine, as it raises the attracting possibility to enhance endogenous progenitor cell functions, finally leading to tissue repair. Therefore, new treatment options have been developed considering the wide spectrum of bone–inflammation interplay, considering in particular the cell intrinsic cues responsible for the modulation of the injured environment. In this review, we will provide a panoramic overview focusing on novel findings developed to uphold endogenous bone repair.

Oncofertility in sarcoma patients.

Treatment for sarcoma can significantly decrease fertility, both due to the irradiation of gonads, and the impact of chemotherapy on gametogenesis. Infertility in cancer survivors causes significant regret and decreased quality of life in their adulthood. As this cancer mainly affects children and young adults, fertility preservation is an essential part of survivorship care, however it remains one of the least implemented services in adolescent and young adult cancer patients. Success of fertility preservation is highly dependent on the referral prior to oncologic treatment. Early patient counseling with possible consult with oncofertility specialists should be offered to every oncologic patient in reproductive age or younger. There are several options available and in continuous evolution for fertility preservation. Cryopreservation of sperm and oocytes constitutes nowadays the standard of care, and should be offered to all patients. Other methods currently under development will potentially bring in the future reliable options for fertility preservation in a wider range of patients, such as those in pre-pubertal age at the time of diagnosis, or with an insufficient sperm count for semen banking. These include testicular sperm extraction (TESE), autologous ovarian tissue transplant, and in vitro maturation of gametes. Novel therapies such as molecular-targeted agents offer a safer toxicity profile regarding fertility, but further research is required to evaluate their impact on the long term, both alone and in combination therapies. Difficulties to access fertility preservation and its costs remain a significant impediment for many patients in need. Warranting access to all sarcoma patients should be a priority in all healthcare professionals involved in their care.

Current Success and Efficiency of Autologous Ovarian Transplantation: A Meta-Analysis.

Ovarian cryopreservation followed by autotransplantation is still considered an experimental strategy for fertility preservation (FP) mainly because the success rates are unknown. To determine cohort epidemiologic characteristics and success rates of autologous ovarian tissue transplantation (OTT) with previously cryopreserved tissue. Literature review from 1999 to October 1, 2016. Additional cases were retrieved from meeting abstracts and own database. We selected studies that reported autologous OTT with previously banked tissue in humans. We did not include any cases involving fresh ovarian tissue transplantation or those performed to treat idiopathic premature ovarian failure/insufficiency. Both authors reviewed and selected studies for eligibility, which resulted in 59 full-text studies assessed for eligibility. Cases were extracted from original reports and reviews by the junior author, and the senior author reviewed and verified the extracted data. Nineteen reports were included for qualitative synthesis. In 10 studies, detailed data were available to determine clinical and live birth + ongoing (LB + OG) pregnancy as well as endocrine restoration rates. Three hundred nine OTTs were performed with cryopreserved tissue, resulting in the birth of 84 children and 8 OG pregnancies. The cumulative clinical and LB + OG rates were 57.5% and 37.7%, respectively, and the endocrine restoration rate was 63.9%. Success rates with cryopreserved OTT have reached promising levels. Given these recent data, ovarian tissue cryopreservation should be considered as a viable option for FP.

Fertility, Cardiac, and Orthopedic Challenges in Survivors of Adult and Childhood Sarcoma.

The combination of cisplatin, doxorubicin, and methotrexate was established as the standard backbone of contemporary osteosarcoma therapy in 1986. Since then, however, further improving the survival of patients with osteosarcoma has been challenging-30% to 40% of patients with osteosarcoma still die of this disease. In addition, these patients often experience loss of fertility at a young age, short- and long-term treatment-related cardiotoxicity, and adverse orthopedic effects from surgical resection of the tumor or endoprosthetic reconstructions. Cancer treatment often markedly increases the risk of infertility later in life, causing many patients substantial distress and regret. Sperm banking and oocyte cryopreservation are standard of care and should be available to all at-risk patients. Newer techniques, such as autologous gonadal tissue transplant for prepubertal children, are being developed, and newer systemic agents have infertility risk profiles that remain undefined and warrant further study. Cost and access remain barriers to these options. The late effects of anthracycline-induced cardiotoxicity are also increasingly a problem for these patients. These effects are often progressive and can be disabling. Adding dexrazoxane to doxorubicin therapy significantly reduces the risk for most adverse cardiac outcomes without compromising the efficacy of induction chemotherapy. Limb salvage surgery remains the standard of care for treatment in the majority of patients with extremity sarcomas. Modular metal prostheses and allograft reconstructions comprised the majority of surgical procedures for limb salvage surgery. The most common mechanism of failure of these implants is infection and mechanical failure of the implant.

Ultrasonic examination of the breast adipose grafts after mammoplasty

To present the results of PRP-adipose grafts implanatation. The study included 25 patients after transplantation of autologous adipose tissue. Autotransplantation was performed to correct volume defects of breast and to restore lost volume after polyacrylamide gel removal in 4 patients; after mastectomy in 6 cases; after complicated replacement using silicone endoprostheses in 11 patients; after previous reduction in 2 cases; after augmentation mammoplasty in 2 cases. Mean age of patients was 42 years. Patients were divided into 2 groups. Group 1 included 12 patients in whom pure adipose tissue was transplanted. Group 2 consisted of 13 patients who received autologous fat with platelet-rich plasma (PRP). Dynamic ultrasonic monitoring showed early resorption processes (liponecrosis foci) after autologous fat injection. Locally increased vascular pattern of breast tissue is an inflammatory sign requiring anti-inflammatory therapy. PRP-adipose grafts have improved outcomes.

Fertility, Cardiac, and Orthopedic Challenges in Survivors of Adult and Childhood Sarcoma

The combination of cisplatin, doxorubicin, and methotrexate was established as the standard backbone of contemporary osteosarcoma therapy in 1986. Since then, however, further improving the survival of patients with osteosarcoma has been challenging-30% to 40% of patients with osteosarcoma still die of this disease. In addition, these patients often experience loss of fertility at a young age, short- and long-term treatment-related cardiotoxicity, and adverse orthopedic effects from surgical resection of the tumor or endoprosthetic reconstructions. Cancer treatment often markedly increases the risk of infertility later in life, causing many patients substantial distress and regret. Sperm banking and oocyte cryopreservation are standard of care and should be available to all at-risk patients. Newer techniques, such as autologous gonadal tissue transplant for prepubertal children, are being developed, and newer systemic agents have infertility risk profiles that remain undefined and warrant further study. Cost and access remain barriers to these options. The late effects of anthracycline-induced cardiotoxicity are also increasingly a problem for these patients. These effects are often progressive and can be disabling. Adding dexrazoxane to doxorubicin therapy significantly reduces the risk for most adverse cardiac outcomes without compromising the efficacy of induction chemotherapy. Limb salvage surgery remains the standard of care for treatment in the majority of patients with extremity sarcomas. Modular metal prostheses and allograft reconstructions comprised the majority of surgical procedures for limb salvage surgery. The most common mechanism of failure of these implants is infection and mechanical failure of the implant.

Technique for subcutaneous forearm transplantation of autologous parathyroid tissue

Technique for subcutaneous forearm transplantation of autologous parathyroid tissue

The Non-Ergot Derived Dopamine Agonist Quinagolide as an Anti-Endometriotic Agent

Aim: The study aimed to investigate the efficacy of a dopamine agonist, quinagolide, on experimentally induced endometriosis in a rat model. Methods: Twenty female Wistar rats were used in this experiment. Endometriosis was surgically induced by transplantation of autologous endometrial tissue. A second laparotomy was performed 4 weeks after the first one to assess the pre-treatment implant volumes, and peritoneal lavage with saline solution was performed to assess the peritoneal cytokine levels. Rats were randomized to treatment with quinagolide or saline. At the end of the treatment period, a third laparotomy was performed to compare pre- and post-treatment implant volumes and cytokine levels within the groups. Implants were excised to compare glandular tissue (GT) and stromal tissue (ST) scores between the groups. Results: In the quinagolide group, post-treatment volume was statistically significantly reduced compared with pre-treatment volume (p = 0.01). There were significant decreases in interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) levels in peritoneal fluid samples in quinagolide-treated rats when compared to pre-treatment levels (p = 0.03 and p < 0.01). Histopathologically, both GT and ST scores were significantly lower in the quinagolide group compared to the control group (p = 0.01 and p = 0.02). Conclusions: Quinagolide caused a significant regression in endometriotic implants and it also significantly reduced the levels of IL-6 and VEGF in peritoneal fluid.

Current Perceptions of Lipofilling on the Basis of the New Guideline on "Autologous Fat Grafting"

Introduction: Autologous fat transfer has recently become an increasingly popular surgical procedure and comprises harvesting, processing and transplantation of adipose tissue, as well as professional follow-up care. This method, as a surgical procedure, can be utilised for trauma-, disease- or age-related soft tissue volume deficits and soft tissue augmentation. As usage is increasing, but the variables of fat harvest, specific indications and fashion of fat transfer are poorly defined, there is a great demand for development of a guideline in the field of reconstructive and aesthetic surgery. Methods: All relevant points were discussed within the scope of a consensus conference including a nominal group process of all societies involved in the procedure and ratified with a strong consensus (>95%). Literature from the standard medical databases over the last 10 years was retrieved, studied and specific guidelines were concluded. Results: Consensus was achieved among all professionals involved on the following points: 1. definition 2. indication/contraindication, 3. preoperative measures 4. donor sites 5. techniques of processing 6. transplantation 7. follow-up care 8. storage 9. efficacy 10. documentation 11. evaluation of patient safety. Conclusion: Definite indications and professional expertise are paramount for autologous fat tissue transfer. Successful transfers are based on the use of correct methods as well as specific instruments and materials. Autologous adipose tissue transplantation is considered to be a safe procedure in reconstructive and aesthetic surgery, due to the low rate of postoperative complications and sequelae.

The fractionation of adipose tissue procedure to obtain stromal vascular fractions for regenerative purposes.

Autologous adipose tissue transplantation is clinically used to reduce dermal scarring and to restore volume loss. The therapeutic benefit on tissue damage more likely depends on the stromal vascular fraction of adipose tissue than on the adipocyte fraction. This stromal vascular fraction can be obtained by dissociation of adipose tissue, either enzymatically or mechanical. Enzymatic dissociation procedures are time-consuming and expensive. Therefore, we developed a new inexpensive mechanical dissociation procedure to obtain the stromal vascular fraction from adipose tissue in a time sparing way, which is directly available for therapeutic injection. This mechanical dissociation procedure is denoted as the fractionation of adipose tissue (FAT) procedure. The FAT procedure was performed in eleven patients. The composition of the FAT-stromal vascular fraction was characterized by immunohistochemistry. Adipose derived stromal cells isolated from the FAT-stromal vascular fraction were compared with adipose derived stromal cells isolated from nondissociated adipose tissue (control) for their CD-surface marker expression, differentiation and colony forming unit capacity. Case reports demonstrated the therapeutic effect of the FAT-stromal vascular fraction. The FAT-stromal vascular fraction is an enrichment of extracellular matrix containing a microvasculature and culturable adipose derived stromal cells. Adipose derived stromal cells isolated from FAT-stromal vascular fraction did not differ from adipose derived stromal cells isolated from the control group in CD-surface marker expression, differentiation and colony forming unit capacity. The FAT procedure is a rapid effective mechanical dissociation procedure to generate FAT-stromal vascular fraction ready for injection with all its therapeutic components of adipose tissue: it contains culturable adipose derived stromal cells embedded in their natural supportive extracellular matrix together with the microvasculature.

Autologous subcutaneous adipose tissue transplants improve adipose tissue metabolism and reduce insulin resistance and fatty liver in diet-induced obesity rats.

Long‐term dietary and pharmacological treatments for obesity have been questioned, particularly in individuals with severe obesity, so a new approach may involve adipose tissue transplants, particularly autologous transplants. Thus, the aim of this study was to evaluate the metabolic effects of autologous subcutaneous adipose tissue (SAT) transplants into two specific intraabdominal cavity sites (omental and retroperitoneal) after 90 days. The study was performed using two different diet‐induced obesity (DIO) rat models: one using a high‐fat diet (HFD) and the other using a high‐carbohydrate diet (HCHD). Autologous SAT transplant reduced hypertrophic adipocytes, improved insulin sensitivity, reduced hepatic lipid content, and fasting serum‐free fatty acids (FFAs) concentrations in the two DIO models. In addition, the reductions in FFAs and glycerol were accompanied by a greater reduction in lipolysis, assessed via the phosphorylation status of HSL, in the transplanted adipose tissue localized in the omentum compared with that localized in the retroperitoneal compartment. Therefore, the improvement in hepatic lipid content after autologous SAT transplant may be partially attributed to a reduction in lipolysis in the transplanted adipose tissue in the omentum due to the direct drainage of FFAs into the liver. The HCHD resulted in elevated fasting and postprandial serum insulin levels, which were dramatically reduced by the autologous SAT transplant. In conclusion, the specific intraabdominal localization of the autologous SAT transplant improved the carbohydrate and lipid metabolism of adipose tissue in obese rats and selectively corrected the metabolic parameters that are dependent on the type of diet used to generate the DIO model.

Peripheral Motor and Sensory Nerve Conduction following Transplantation of Undifferentiated Autologous Adipose Tissue-Derived Stem Cells in a Biodegradable U.S. Food and Drug Administration-Approved Nerve Conduit.

Conduits preseeded with either Schwann cells or stem cells differentiated into Schwann cells demonstrated promising results for the outcome of nerve regeneration in nerve defects. The concept of this trial combines nerve repair by means of a commercially available nerve guidance conduit and preseeding with autologous, undifferentiated, adipose tissue-derived stem cells. Adipose tissue-derived stem cells were harvested from rats and subsequently seeded onto a U.S. Food and Drug Administration-approved type I collagen conduit. Sciatic nerve gaps 10 mm in length were created, and nerve repair was performed by the transplantation of either conduits preseeded with autologous adipose tissue-derived stem cells or acellular (control group) conduits. After 6 months, the motor and sensory nerve conduction velocity were assessed. Nerves were removed and examined by hematoxylin and eosin, van Gieson, and immunohistochemistry (S100 protein) staining for the quality of axonal regeneration. Nerve gaps treated with adipose tissue-derived stem cells showed superior nerve regeneration, reflected by higher motor and sensory nerve conduction velocity values. The motor and sensory nerve conduction velocity were significantly greater in nerves treated with conduits preseeded with adipose tissue-derived stem cells than in nerves treated with conduits alone (p < 0.05). Increased S100 immunoreactivity was detected for the adipose tissue-derived stem cell group. In this group, axon arrangement inside the conduits was more organized. Transplantation of adipose tissue-derived stem cells significantly improves motor and sensory nerve conduction velocity in peripheral nerve gaps. Preseeded conduits showed a more organized axon arrangement inside the conduit in comparison with nerve conduits alone. The approach used here could readily be translated into a clinical therapy. Therapeutic, V.

Autologous fat tissue injection improve the quality of skin grafts: A Novel Therapeutic measurement for wound lesion

Abstract Background and objective Autologous fat tissue transplantation is becoming rapidly popular in the field of research and therapy. Because adipose tissue contains adipose derived stem cells, clinical improvements in many fields after autologous fat graft are well described in literature. In this paper, we present our observation of autologous fat graft experience in improving the quality of skin grafts including both aesthetic appearance and function. Materials and methods 21 patients recruited were given surgical operation of skin graft. After skin graft survived, we performed fat tissue injection with Coleman technique into skin grafts. In all skin grafts, clinical assessment for aesthetic appearance and hardness of skin grafts was performed using Patient and Observer Skin Graft Assessment Scale (POSGAS) and durometer measurements, respectively. Results In all the skin grafts that got fat tissue injection, a qualitative improvement was shown from an aesthetic appearance; most importantly, skin grafts’ elasticity were objectively improved. According to the data of durometer and POSGAS score, autologous fat tissue injection showed statistically significant reduction in hardness in comparison with the control. POSGAS scores showed a statistically significant reduction of a great deal of POSGAS parameters as a result of an improvement of both clinical evaluation and patient perception. Conclusions Injection of autologous fat seems to be a promising and effective therapeutic approach for the improvement of aesthetic appearance and function of skin grafts; which could make both surgeons and patients obtain more satisfactory rate in surgical operation of skin grafts.

Feasibility and potential value of lipofilling in post-treatment oropharyngeal dysfunction.

Head and neck cancer (HNC) patients may develop oropharyngeal dysfunction as result of volume loss or muscle atrophy of the tongue or pharyngeal musculature following treatment with surgery and/or chemoradiotherapy. If intensive swallowing therapy offers no further improvement, and the functional problems persist, transplantation of autologous adipose tissue (lipofilling) might restore functional outcomes by compensating the existing tissue defects or tissue loss. Case series. In this prospective pilot feasibility study, the application of lipofilling was studied in seven HNC patients with chronic dysphagia. The procedure was carried out under general anesthesia in several sessions using the Coleman technique. Swallowing outcomes were evaluated with standard videofluoroscopy (VFS) for obtaining objective Penetration Aspiration Scale (PAS) and residue scores. Subjective Functional Oral Intake Scale scores and Swallowing Quality of Life Questionnaire were also completed. Magnetic resonance imaging was used to evaluate the post-treatment injected fat. Five patients completed the intended three lipofilling sessions, whereas two completed two injections. One patient dropped out of the study after two injections because of progressive dysphagia requiring total laryngectomy. Four of the six remaining patients showed improved PAS scores on post-treatment VFS assessments, with two patients no longer showing aspiration for a specific consistency. Two patients were no longer feeding tube dependent. Patient-reported swallowing and oral intake improved in four out of six patients. Based on the results, the lipofilling technique seems safe and, in selected cases, of potential value for improving swallowing function in this small therapy-refractory HNC patient cohort. 4 Laryngoscope, 126:2672-2678, 2016.

Induction of adipose-derived stem cells on injectable nanofibrous spongy microspheres for vascularized adipose tissue regeneration in vivo

Event Abstract Back to Event Induction of adipose-derived stem cells on injectable nanofibrous spongy microspheres for vascularized adipose tissue regeneration in vivo Yasmine Doleyres1, Xiaobing Jin2 and Peter X. Ma1, 2, 3, 4 1 University of Michigan, Macromolecular Science and Engineering Program, United States 2 University of Michigan, Department of Biologic and Materials Sciences, United States 3 University of Michigan, Department of Biomedical Engineering, United States 4 University of Michigan, Department of Materials Science and Engineering, United States Soft tissue defects in the craniofacial region or the breast region often occur due to congenital defects, traumatic injury, or cancer occurring in the underlying tissue[1]. Correcting these defects in the case of facial reconstruction can be done by transplanting adipose (fat) tissue from another area of the body into the facial region or in the case of reconstruction following breast cancer can be done through autologous tissue transplantation, if available, or using silicone or saline-filled implants. The problem with these options is that between 20-90% of transplanted fat tissue often resorbs within a couple months after being transplanted due to lack of vascularization and implants often fail because of capsular constriction and become infected, leading to multiple surgeries in both cases[1]-[8]. The most ideal option would be to regenerate one’s own adipose tissue just as it is naturally produced by the body. Lasting tissue regeneration options for in vivo adipose tissue have yet to be developed, and this is the goal of this project. Novel nanofibrous spongy (porous) microspheres (NF-SMS) have been developed and appear to be a suitable scaffolding or cell-carrying material for the differentiation and growth of adipose-derived stem cells (ASCs). These microspheres made of poly-L-lactic acid (PLLA) have a nanofibrous architecture that well-mimics the cells’ natural extracellular matrix and also allows for cells to pack the interior of the microspheres[9]. A high number of cells are able to pack into the interior of the microspheres and the high cell attachment on the microspheres is critical for adipose tissue regeneration as high cell-cell contact is necessary for tissue growth. Adipogenesis of the isolated ASCs is induced for 3-4 days in growth medium containing Dexamethasone, Indomethacin, and 3-isobuytl-1-methylxanthine (IBMX)[10],[11]. The cells are then combined with the microspheres for a few hours and subsequently injected subcutaneously in a nude mouse model for testing. Early in vitro experiments comparing the growth and differentiation of the cells on the NF-SMS against enclosed nanofibrous hollow microspheres as a control show increased cell attachment and integration on the NF-SMS. The cells on the NF-SMS also showed greater Nile Red lipid staining and overall positive results in vitro. Current in vivo experiments are being done and are incorporating poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with insulin for sustained released of insulin from these particles during the early period of growth (1-2 weeks). Insulin appears to be very critical in the adipogenesis pathway and should be crucial in helping to produce substantial tissue in vivo[12]-[14]. These PLGA nanoparticles are injected along with the microsphere-cell complexes. Having a patient regenerate adipose tissue from their own pre-adipocyte cells will be advantageous because it eliminates the need for something foreign in the body and multiple invasive surgeries. Ensuring that the adipose tissue produced does not resorb as is the case in previous research attempts would be done by functionalizing the microsphere scaffolds with an angiogenic factor, which is the next goal of this project.