Ectopic bone formation by aggregated mesenchymal stem cells from bone marrow and adipose tissue: A comparative study.

Tissue engineered constructs (TECs) based on spheroids of bone marrow mesenchymal stromal cells (BM-MSCs) combined with calcium phosphate microparticles and enveloped in a platelet-rich plasma hydrogel showed that aggregation of MSCs improves their ectopic bone formation potential. The stromal vascular fraction (SVF) and adipose-derived MSCs (ASCs) have been recognized as an interesting MSC source for bone tissue engineering, but their ectopic bone formation is limited. We investigated whether aggregation of ASCs could similarly improve ectopic bone formation by ASCs and SVF cells. The formation of aggregates with BM-MSCs, ASCs and SVF cells was carried out and gene expression was analysed for osteogenic, chondrogenic and vasculogenic genes in vitro. Ectopic bone formation was evaluated after implantation of TECs in immunodeficient mice with six conditions: TECs with ASCs, TECs with BM-MSC, TECs with SVF cells (with and without rhBMP2), no cells and no cells with rhBMP2. BM-MSCs showed consistent compact spheroid formation, ASCs to a lesser extent and SVF showed poor spheroid formation. Aggregation of ASCs induced a significant upregulation of the expression of osteogenic markers like alkaline phosphatase and collagen type I, as compared with un-aggregated ASCs. In vivo, ASC and SVF cells both generated ectopic bone in the absence of added morphogenetic proteins. The highest incidence of bone formation was seen with BM-MSCs (7/9) followed by SVF + rhBMP2 (4/9) and no cells + rhBMP2 (2/9). Aggregation can improve ectopic bone tissue formation by adipose-derived cells, but is less efficient than rhBMP2. A combination of both factors should now be tested to investigate an additive effect.

Implantation of Stromal Vascular Fraction Progenitors at Bone Fracture Sites: From a Rat Model to a First-in-Man Study.

Stromal Vascular Fraction (SVF) cells freshly isolated from adipose tissue include osteogenic- and vascular-progenitors, yet their relevance in bone fracture healing is currently unknown. Here, we investigated whether human SVF cells directly contribute to the repair of experimental fractures in nude rats, and explored the feasibility/safety of their clinical use for augmentation of upper arm fractures in elderly individuals. Human SVF cells were loaded onto ceramic granules within fibrin gel and implanted in critical nude rat femoral fractures after locking-plate osteosynthesis, with cell-free grafts as control. After 8 weeks, only SVF-treated fractures did not fail mechanically and displayed formation of ossicles at the repair site, with vascular and bone structures formed by human cells. The same materials combined with autologous SVF cells were then used to treat low-energy proximal humeral fractures in 8 patients (64-84 years old) along with standard open reduction and internal fixation. Graft manufacturing and implantation were compatible with intraoperative settings and led to no adverse reactions, thereby verifying feasibility/safety. Biopsies of the repair tissue after up to 12 months, upon plate revision or removal, demonstrated formation of bone ossicles, structurally disconnected and morphologically distinct from osteoconducted bone, suggesting the osteogenic nature of implanted SVF cells. We demonstrate that SVF cells, without expansion or exogenous priming, can spontaneously form bone tissue and vessel structures within a fracture-microenvironment. The gained clinical insights into the biological functionality of the grafts, combined with their facile, intra-operative manufacturing modality, warrant further tests of effectiveness in larger, controlled trials. Stem Cells 2016;34:2956-2966.

Effects of intersyringe processing on adipose tissue and its cellular components: implications in autologous fat grafting.

BACKGROUND: Autologous fat grafting is a popular technique in plastic surgery. A mechanical processing method is used to facilitate fat injection. No study has investigated whether this process affects cell quality and preservation of biological functionality. This study analyzed the influence of quick mechanical processing through two interconnected small-diameter syringes ("shuffling") on both structure and viability of fat tissue, and on viability, clonogenicity, and differentiation of the freshly isolated stromal vascular fraction. METHODS: Lipoaspiration was performed in six healthy donors, followed by shuffling the fat either zero, five, or 30 times between two 10-cc syringes. Thereafter, fat was applied through a 1.5-mm cannula as in a clinical setting for autologous fat grafting. Analysis of different treatment conditions was conducted. Immunofluorescent staining allowed assessment of morphology, viability, composition, and damage of the tissue. The stromal vascular fraction was examined for isolation yield, viability, clonogenicity, and differentiation capacity. RESULTS: The process of shuffling changed the macroscopic but not the microscopic structure of the lipoaspirated fat. No difference in cell number, viability, number of lipid droplets, vascular architecture, or ratio of cell composition was found. Analysis of the stromal vascular fraction, apart from large interdonor variability, did not show a significant change in isolation yield, viability, clonogenicity, or adipogenic differentiation capacity of the expanded cells. CONCLUSIONS: The mechanical procedure of shuffling lipoaspirated fat does not alter its tissue viability or its microscopic structure. The absence of impact on the stromal vascular fraction in the assessed parameters suggests that shuffling can be executed according to surgical needs.

Efficacy, safety and complications of autologous fat grafting to healthy breast tissue: a systematic review.

BACKGROUND: Fat grafting for primary breast augmentation is growing in popularity due to its autologous properties and its side benefit of removing unwanted fat from other areas, although volume gain is unpredictable and patient safety remains unclear. OBJECTIVE: The aim of this study was to provide an evidence-based overview of autologous fat grafting to healthy breast tissue with focus on volume gain, safety and complications. DESIGN: A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. DATA SOURCES: The MEDLINE, Cochrane Library and EMBASE databases were searched for clinical studies on autologous fat grafting to healthy breast tissue within the last 30 years. DATA EXTRACTION: Clinical articles were evaluated for indication, pre- and postoperative work-up, surgical technique, volume gain (efficacy), complications, radiographic changes and oncological safety. The level of evidence was assessed according to the Oxford Centre for Evidence-based Medicine 2011. RESULTS: A total of 36 articles involving 1453 patients with a mean follow-up period of 16.3 months (1-156 months) were included. No randomised controlled studies were found. Six percent of the patients undergoing fat grafting to healthy breast tissue experienced major complications requiring a surgical intervention or hospitalisation. Two patients with breast cancer (0.1%) after fat grafting for cosmetic purposes were reported. Average breast volume gain ranged from 55% to 82% relative to the grafted fat volume. CONCLUSIONS: The prevalence of complications and re-operations in fat grafting to healthy breast tissue compared favourably to implant-based breast augmentation. Although no increased incidence of breast cancer was found, long-term breast cancer screening and the implementation of publicly accessible registries are critically important to proving the safety of fat grafting.

Second free radial forearm flap for urethral reconstruction after partial flap necrosis of tube-in-tube phalloplasty with radial forearm flap: a report of two cases.

We present a salvage procedure to reconstruct the neo-urethra after partial flap necrosis occurring in free radial forearm flap (RFF) phalloplasty for sex reassignment surgery. Two cases of tube-in-tube phalloplasty using a free sensate RFF are described in which partial flap necrosis occurred involving the complete length of the neo-urethra and a strip of the outer lining of the neo-phallus. Neo-urethra-reconstruction was performed with a second RFF from the contralateral side providing well-vascularized tissue. No flap-related complications were observed. Twelve months postoperatively, both patients were able to void while standing. A satisfactory aesthetic appearance of the neo-phallus could be preserved with an excellent tactile and erogenous sensitivity. Using this technique, we successfully salvaged the neo-urethra and reconstructed the outer lining of the neo-phallus