ObjectiveTo investigate the necessity of subcutaneous suture for gynecologic abdominal incision, and to prove the clinical value of suture without subcutaneous ligature. MethodsWe retrospectively studied the clinical data of 210 cases of gynecologic abdominal incision treated between May 2010 and May 2013. A total of 111 cases had the suture without subcutaneous ligature and 99 received the traditional suture. ResultsOne patient (0.90%) had fat liquefaction in the group of suture without subcutaneous ligature, while 7 (7.07%) of fat liquefaction were found in the traditional suture group, and the difference was statistically significant (χ2=3.883, P=0.049). No hospital infection occurred. The healing period averaged (15.1±4.7) days, and the patients were followed up for 2 months without any complication of abdominal incision in all the patients. ConclusionSuture without subcutaneous ligature is simple and easy to practice, with precise effect, which deserves clinical application.
Objective To review research progress of adipose tissuederived stromal cells (ADSCs).Methods The recent articles on ADSCs were extensively reviewed, and the culture and differentiation ability of ADSCs were investigated.Results A population of stem cells could be isolated from adult adipose tissue, they were processed to obtain a fibroblast-like population of cells and could be maintained in vitro for extended periods with stable population doubling. The majority of the isolated cells were mesenchymal origin, with a few pericytes,endothelial cells and smooth muscle cells. ADSCs could be induced to differentiate intomultiple mesenchymal cell types, including osteogenic, chondrogenic, myogenic and adipogenic cells, they could also differentiate into nerve cells.Conclusion ADSCs can substitute mesenchymal stem cells and become an alternative stem cells source for tissue engineering.
ObjectiveTo evaluate the mechanism of stromal vascular fraction (SVF) promoting angiogenesis and tissue regeneration in tissue engineering chamber. MethodsTwenty-four 6-month-old New Zealand white rabbits, male or female, weighing 2.5-2.8 kg, were selected. Thoracic dorsal arteriovenous bundle combined with collagen type I scaffold was transplanted to dorsal side, and wrapped by cylindrical hollow silicone chamber; all animals were randomly divided into the experimental group (n=12) and the control group (n=12). SVF was isolated from the back fat pads of rabbits in experimental group and labelled with DiI at 2 weeks after operation. The 1 mL cell suspension (1×106 cells/mL) and equal saline were injected into the chamber in experimental group and control group, respectively. The regenerative tissues were harvested for general observation and HE staining at 2 and 4 weeks after injection;and immunofluorescent staining was carried out in experimental group at 4 weeks. ResultsAt 2 weeks after injection, the regenerative tissue was cylindrical; obvious vessel network and incompletely degradable collagen scaffold could be seen on the surface of the new tissue in 2 groups. The volume of new tissue was (0.87±0.11) mL in experimental group, and (0.72±0.08) mL in control group at 2 weeks, showing significant difference (t=2.701, P=0.011). At 4 weeks, little collagen scaffold could be seen on the surface in control group, but no collagen scaffold in experimental group; the volume of new tissue was (0.74±0.14) mL in experimental group, and (0.64±0.10) mL in control group, showing no significant difference (t=1.424, P=0.093). HE staining showed new mature vessels at 4 weeks, but no adipose tissue or fat lobulus formed in both groups; the capillary density was significantly higher in experimental group than in control group at 2 weeks (t=6.291, P=0.000) and at 4 weeks (t=5.445, P=0.000). The immunofluorescent staining found that SVF survived and located at the edge area after 4 weeks; the expressions of CD31 and DiI were positive in some endothelial cells. ConclusionSVF can promote the angiogenesis and tissue regeneration in tissue engineering chamber, but it can not differentiate into adipocyte spontaneously without adipogenic microenvironment.
ObjectiveTo prepare human acellular adipose tissue matrix and to evaluate the cellular compatibility so as to explore a suitable bio-derived scaffold for adipose tissue engineering. MethodsThe adipose tissue was harvested from abdominal skin graft of breast cancer patients undergoing radical mastectomy or modified radical mastectomy, and then was treated with a series of decellularization processes including repeated freeze-thaw, enzyme digestion, and organic solvent extraction. The matrix was examined by histology, immunohistochemistry, DAPI fluorescence staining, and scanning electron microscopy to observe the the removal of cells and to analyze its composition of collagen type IV, laminin, and fibronectin, and microstructure. The 3rd passage human adipose-derived stem cells (hADSCs) were co-cultured with acellular adipose tissue matrix and different concentrations of extracted liquid (100%, 75%, 50%, and 25%). The cytotoxic effects of the matrix were tested by MTT. The biocompatibility of the matrix was detected by live/dead staining and scanning electron microscopy observation. ResultsThe acellular adipose tissue matrix basically maintains intrinsical morphology. The matrix after acellular treatment consisted of extracellular matrix without any cell components, but there were abundant collagen type I; neither DNA nor lipid residual was detected. Moreover, the collagen was the main component of the matrix which was rich in laminin and fibronectin. At 1, 3, and 5 days after co-cultured with hADSCs, the cytotoxic effect of matrix was grade 0-1. The matrix displayed good cell compatibility and proliferation. ConclusionThe acellular adipose tissue matrix prepared by repeated freeze-thaw, enzyme digestion, and organic solvent extraction method remains abundant extracellular matrix and has good cellular compatibility, so it is expected to be an ideal bio-derived scaffold for adipose tissue engineering.
ObjectiveTo explore the possibility of constructing tissue engineered adipose by adipose tissue derived extracellular vesicles (hAT-EV) combined with decellularized adipose tissue (DAT) scaffolds, and to provide a new therapy for soft tissue defects.MethodsThe adipose tissue voluntarily donated by the liposuction patient was divided into two parts, one of them was decellularized and observed by HE and Masson staining and scanning electron microscope (SEM). Immunohistochemical staining and Western blot detection for collagen type Ⅰ and Ⅳ and laminin were also employed. Another one was incubated with exosome-removed complete medium for 48 hours, then centrifuged to collect the medium and to obtain hAT-EV via ultracentrifugation. The morphology of hAT-EV was observed by transmission electron microscopy; the nanoparticle tracking analyzer (NanoSight) was used to analyze the size distribution; Western blot was used to analyse membrane surface protein of hAT-EV. Adipose derived stem cells (ADSCs) were co-cultured with PKH26 fluorescently labeled hAT-EV, confocal fluorescence microscopy was used to observe the uptake of hAT-EV by ADSCs. Oil red O staining was used to evaluate adipogenic differentiation after hAT-EV and ADSCs co-cultured for 15 days. The DAT was scissored and then injected into the bilateral backs of 8 C57 mice (6-week-old). In experimental group, 0.2 mL hAT-EV was injected weekly, and 0.2 mL PBS was injected weekly in control group. After 12 weeks, the mice were sacrificed, and the new fat organisms on both sides were weighed. The amount of new fat was evaluated by HE and peri-lipoprotein immunofluorescence staining to evaluate the ability of hAT-EV to induce adipogenesis in vivo.ResultsAfter acellularization of adipose tissue, HE and Masson staining showed that DAT was mainly composed of loosely arranged collagen with no nucleus; SEM showed that no cells and cell fragments were found in DAT, and thick fibrous collagen bundles could be seen; immunohistochemical staining and Western blot detection showed that collagen type Ⅰ and Ⅳ and laminin were retained in DAT. It was found that hAT-EV exhibited a spherical shape of double-layer envelope, with high expressions of CD63, apoptosis-inducible factor 6 interacting protein antibody, tumor susceptibility gene 101, and the particle size of 97.9% hAT-EV ranged from 32.67 nmto 220.20 nm with a peak at 91.28 nm. Confocal fluorescence microscopy and oil red O staining showed that hAT-EV was absorbed by ADSCs and induced adipogenic differentiation. In vivo experiments showed that the wet weight of fat new organisms in the experimental group was significantly higher than that in the control group (t=2.278, P=0.048). HE staining showed that the structure of lipid droplets in the experimental group was more than that in the control group, and the collagen content in the control group was higher than that in the experimental group. The proportion of new fat in the experimental group was significantly higher than that in the control group ( t=4.648, P=0.017).ConclusionDAT carrying hAT-EV can be used as a new method to induce adipose tissue regeneration and has a potential application prospect in the repair of soft tissue defects.
Objective Extracellular matrix is one of the focus researches of the adi pose tissue engineering. To investigate the appropriate method to prepare the porcine skeletal muscle acellular matrix and to evaluate the biocompatibility of the matrix. Methods The fresh skeletal muscle tissues were harvested from healthy adult porcine and were sl iced into2-3 mm thick sheets, which were treated by hypotonic-detergent method to remove the cells from the tissue. The matrix was then examined by histology, immunohistochemistry, and scanning electron microscopy. The toxic effects of the matrix were tested by MTT. Human adi pose-derived stem cells (hADSCs) were isolated from adi pose tissue donated by patients with breast cancer, and identified by morphology, flow cytometry, and differentiation abil ity. Then, hADSCs of passage 3 were seeded into the skeletal muscle acellular matrix, and cultured in the medium. The cellular behavior was assessed by calcein-AM (CA) and propidium iodide (PI) staining at 1st, 3rd, 5th, and 7th days after culturing. Results Histology, immunohistochemistry, and scanning electron microscopy showed that the muscle fibers were removed completely with the basement membrane structure; a large number of collagenous matrix presented as regular network, porous-like structure. The cytotoxicity score of the matrix was grade 1, which meant that the matrix had good cytocompatibil ity. The CA and PI staining showed the seeded hADSCs had the potential of spread and prol iferation on the matrix. Conclusion Porcine skeletal muscle acellular matrix has good biocompatibility and a potential to be used as an ideal biomaterial scaffold for adi pose tissue engineering.
【Abstract】 Objective To explore the optimal dosage, timing and cytotoxicity of bromodeoxyuridine (BrdU) labelling for rabbit adipose-derived stromal stem cells (ADSCs) in vitro so as to confirm its feasibil ity for stem cells labell ing and tracer means. Methods Six rabbits were used in this experiment, aged 8-12 weeks, weighing 1.5-2.0 kg and neglecting their gender. 1-2 mL fat was removed, the ADSCs were isolated and cultured using the adherence method in vitro . The 3rd passage of ADSCs was incubated with BrdU at 5, 10, 15 and 20 μg/mL (groups A, B, C and D）for 12, 24, 48 and 72 hours to identify the optimal BrdU concentration and incubating time for cell labell ing. Immunohistochemistry and trypanblau strain were performed respectively to calculate the labell ing index (positive rate) and the cells’ activity for different time after BrdU labell ing. The ADSCs without BrdU labell ing were used as control (Group E）. Results The main appearance of primary ADSCs was short fusiform shape, and of the 3rd passage ADSCs long fusiform shape. The 3rd passage of ADSCs could differentiate into osteoblastsand adipocytes under corresponding inductive medium. The ADSCs’ nucleus show green fluor under fluorescence microscope after labeled by the BrdU. The labell ing ratio increased in groups A, B, C and D after incubating 12 hours, the mean labell ing ratio were 30.6％ ±2.3％，32.4％ ±1.9％，45.8％ ±1.8％，50.8％ ±3.1％ , respectively, and the labell ing ratio of Group E was 0. There were significant differences between groups C, D and Group A (P lt; 0.01). The labell ing ratio of groups A, B, C and D were 45.9％ ±2.0％，87.9％ ±3.3％，90.6％ ±2.9％，91.7％ ±3.2％，respectively after 24 hours and the labell ing ratio of Group E was 0. There were significant differences between groups B, C, D and Group A (P lt; 0.01). The results of all groups after incubating48 hours and 72 h ours were similar to that after incubating 24 hours. The cell counting of groups A, B, C and D were better than that of Group E, but showing no siginificant differences（P gt; 0.05）. Conclusion The most appropriate time for BrdU labell ing ADSCs is 48 hours, the most appropriate concentration is 10 μg/mL. The labell ing rate is high and cytotoxicity is l ittle.
Objective Seed cells are the hotspot of tissue engineering research. To study the seed cells with high potential of adipogenic differentiation for applying the adipose tissue engineering and increasing the constructing efficiency of adipose tissue engineering. Methods Mature adipocytes (MA) and adipose-derived stromal cells (ADSCs) were harvestedfrom human fat aspirates via l iposuction by collagenase digestion. MA were cultured and induced to dedifferentiated adipocytes (DA) by ceil ing adherent culture method. DA and ADSCs were induced to adipogenic differentiation. The adipogenic abil ities of DA and ADSCs were compared by inverted phase contrast microscope observation, absorption spectrometry assay of oil red O staining, and cell counting of oil red O staining. Results MA could dedifferentiate into fibroblast-shaped DA. After adi pogenic differentiation, the inverted phase contrast microscope observation showed that there were much more l i pid droplet in DA than in ADSCs. Absorption spectrometry assay of oil red O staining showed there were significant l ipid droplet aggregation in DA 4 days of adipogenic induction. However, the same phenomenon could be observed in ADSCs at 10 days after differentiation. After 12 days, the absorption value of DA was higher than that of ADSCs, showing significant difference (P lt; 0.05). The cell counting of oil red O staining demonstrated that the adipogenic rates of DA and ADSCs were 65% ± 6% and 35% ± 5%, respectively, showing significant difference (P lt; 0.05). Conclusion The potential of adipogenic differentiation of DA is ber than that of ADSCs. DA is a promising seed cell of adipose tissue engineering.
ObjectiveTo summarize recent progress in adipose tissue acting as a more efficient and ideal therapy to facilitate wound repair and evaluate the therapeutic values of adipose tissue.MethodsThe related literature about adipose tissue for wound healing in recent years was reviewed and analyzed.ResultsEnormous studies focus on the capacity of adipose tissue to accelerate wound healing including cellular components, extracellular matrix, and paracrine signaling have been investigated.ConclusionAdipose tissue has generated great interest in recent years because of unique advantages such as abundant and accessible source, thriven potential to enhance the regeneration and repair of damaged tissue. However, there is still a need to explore the mechanism that adipose tissue regulates cellular function and tissue regeneration in order to facilitate clinical application of adipose tissue in wound healing.