Stem Cell-Enriched Fat Grafts Versus Autologous Fat Grafts for Facial Reconstruction: A Systematic Review and Meta-analysis.

OBJECTIVE: The aim of the study is to compare the outcomes of stem cell-enrichment fat grafting versus routine fat grafting for facial reconstruction purposes. METHODS: A systematic review and meta-analysis were performed as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses Guidelines and a search of electronic information was conducted to identify all randomized controlled trials, case control studies, and cohort studies comparing the outcomes of stem cell enrichment fat grafting versus routine fat grafting for facial reconstruction purposes. Volume retention and infection rate were primary outcome measures. Secondary outcome measures included patient satisfaction postsurgery, redness and swelling, fat necrosis, cysts, as well as operation time. Fixed and random effects modeling was used for the analysis. RESULTS: Eight studies enrolling 275 subjects were selected. There was a significant difference between the stem cell enrichment fat grafting and routine grafting groups in terms of mean volume retention (standardized mean difference, 2.49; P < 0.00001). However, there was no significant difference between the 2 groups in the rate of infection (odds ratio, 0.36; P = 0.30). For all secondary outcomes, the intervention group had similar results compared with the control group except for the operation time, which was shorter in the latter. CONCLUSIONS: Stem cell-enriched fat grafting is a superior option when compared with the routine fat grafting for facial reconstruction surgery because it improves the mean volume retention and does not worsen patient satisfaction and surgical complications.

Optimizing the decellularization process of an upper limb skeletal muscle; implications for muscle tissue engineering.

Upper limb muscle reconstruction is required following cancer resection, trauma, and congenital deformities. Current surgical reconstruction of the muscle involves local, regional and free flaps. However, muscle reconstruction is not always possible due to the size of the defect and functional donor site morbidity. These challenges could be addressed with the production of scaffolds composed of an extracellular matrix (ECM) derived from decellularized human skeletal muscle. This study aimed to find an optimal technique to decellularize a flexor digitorum superficialis muscle. The first two protocols were based on a detergent only (DOT) and a detergent-enzymatic protocol (DET). The third protocol avoided the use of detergents and proteolytic enzymes (NDNET). The decellularized scaffolds were characterized using qualitative techniques including histological and immunofluorescent staining and quantitative techniques assessing deoxyribonucleic acid (DNA), glycosaminoglycan (GAG), and collagen content. The DOT protocol consisting of 2% SDS for 4 hours was successful at decellularizing human FDS, as shown by DNA content assay and nuclei immunofluorescence staining. The DOT protocol maintained the microstructure of the scaffolds as shown by Masson's trichrome staining and collagen and GAG content. DET and NDNET protocols maintained the ECM, but were unsuccessful in removing all DNA content after two cycles of decellularization. Decellularization of skeletal muscle is a viable option for muscle reconstruction using a detergent only technique for upper limb defects. Further testing in vivo will assess the effectiveness of decellularized scaffolds for upper limb muscle skeletal tissue engineering.

Optimizing the decellularization process of human maxillofacial muscles for facial reconstruction using a detergent-only approach.

Trauma, congenital diseases, and cancer resection cause muscle deformities of the human facial muscle. Muscle defects are either treated with local or distal flaps if direct closure is not possible. However, such surgical interventions are limited by donor morbidity and limited tissue availability. Decellularized scaffolds provide alternative strategies for replacing and restoring missing facial muscle by creating scaffolds that mimic the native tissue. This study aimed to develop a protocol to decellularize human zygomaticus major muscle (ZMM) and masseter muscle (MM). Three protocols were assessed including a detergent-only treatment (DOT), detergent-enzymatic treatment (DET) protocol, and a third nondetergent nonenzymatic treatment protocol. Scaffolds were then characterized via histological, immunofluorescent, and quantitative techniques to assess which protocol provided optimal decellularization and maintenance of the extracellular matrix (ECM). The results demonstrated three cycles of DOT protocol consisting of 2% sodium dodecyl sulfate for 4 hr was optimal for decellularization for both ZMM and MM. After three cycles, DNA content was significantly reduced compared with native ZMM and MM (p < .05) with preservation of collagen and glycosaminoglycan content and ECM on histological analysis. DET and nondetergent nonenzymatic treatment protocols were unsuccessful in decellularizing the ZMM and MM with residual DNA content after four cycles and caused ECM disruption on histological analysis. All protocols did not impair the mechanical properties and supported human fibroblast growth. In conclusion, the DOT protocol is effective in producing human decellularized muscle scaffolds that maintain the ECM. Further investigation of detergent only decellurization techniques should be explored as a first step to create effective scaffolds for muscle tissue engineering.

Optimising the decellularization of human elastic cartilage with trypsin for future use in ear reconstruction.

Decellularized scaffolds can induce chondrogenic differentiation of stem cells. This study compares different methods to optimise the decellularization of auricular cartilage. The process consisted of an initial 12 hour dry freeze thaw which froze the cartilage specimens in an empty tube at -20 °C. Samples were allowed to thaw at room temperature followed by submersion in phosphate buffer solution in which they were frozen at -20 °C for a 12 hour period. They were then allowed to thaw at room temperature as before. Protocol A subsequently involved subjecting specimens to both deoxyribonuclease and sodium deoxycholate. Protocol B and C were adaptations of this using 0.25% trypsin (7 cycles) and a 0.5 molar solution of ethylenediaminetetraacetic acid (3 hours for each cycle) respectively as additional steps. Trypsin accelerated the decellularization process with a reduction in DNA content from 55.4 ng/µL (native) to 17.3 ng/µL (P-value < 0.05) after 14 days. Protocol B showed a faster reduction in DNA content when compared with protocol A. In comparison to protocol C after 14 days, trypsin also showed greater decellularization with a mean difference of 11.7 ng/µL (P-value < 0.05). Histological analysis with H&E and DAPI confirmed depletion of cells at 14 days with trypsin.