Comparative study of the integration and viability of autonomised and nonautonomised autologous fat tissue grafts--experimental model in rabbits

Ear reconstruction research using animal models: The effect of fat grafting on costal cartilage stents

OBJECT

For congenital microtia patients with a depressed mastoid area, it is unclear whether autologous fat grafting to fill the depressed area of the cheek will affect the survival of the subsequent grafted costal cartilage stent. An animal model was used for in vivo research to provide guidance for clinical applications.

METHODS

Autologous costal cartilage was implanted in nude mice. Fat samples were collected at different time points and histological examination performed to analyze the activity of chondrocytes and the deposition of the chondrocyte matrix.

RESULTS

This nude mouse fat transplantation model study showed that there were statistical differences in chondrocyte viability between the fat filling group and the control group, but there was no statistical difference in the effect on collagen content.

CONCLUSION

Transplanting fat reduces the viability of chondrocytes, but has little effect on collagen matrix deposition.

The Effect of Locally Delivered Apocynin on Fat Graft Survival in an Experimental Rat Animal Model

OBJECTIVES

We aimed to investigate the efficacy of locally delivered apocynin on fat graft survival in an experimental autologous fat grafting (AFG) model created in rats.

METHODS

Twenty-one Wistar albino male rats were included in this study. The 0.647 g mean weight grafts were harvested from the inguinal region and transferred to the nape of every rat. The subjects were randomly separated into three groups. Saline, dimethyl sulfoxide (DMSO) and apocynin, a dose of 20 mg/kg, solutions were applied once a day for 2 weeks. After 3 months, the rats were sacrificed. The evaluation of physical measurements (weight and volume) and survival rates of the grafts for volume (SRV) and weight (SRW), the viable cell count (VC) with the MTT assay, and histopathological parameters were done.

RESULTS

All biophysical parameters were found to be significantly higher in the apocynin group compared to other groups (p < .05). In the MTT test, the saline group was normalized to 100%. According to this, DMSO and apocynin groups' means were 106% and 163%, respectively. The VC was significantly higher in the apocynin group than the other groups (p < .05). The VC was significantly higher in the DMSO group than in the saline group (p < .05). No significant difference was found in other comparisons performed according to biophysical and histopathological parameters (p > .05).

CONCLUSION

The locally delivered apocynin decreases fat graft volume loss in an experimental AFG model. Consequently, apocynin can be used as an effective substance to increase graft survival.

The Effect of Apocynin on Fat Graft Survival

BACKGROUND

In this study, we investigated the effect of apocynin on fat graft survival in a rat model.

METHODS

Twenty-one Wistar albino male rats were included in the study. The grafts taken from the inguinal area were applied to the nape of each rat. The rats were randomly divided into three groups. Apocynin+DMSO, DMSO and saline were administered intraperitoneally once daily for 14 days. After 90 days, the animals were sacrificed and the grafts were excised. The weights and volumes were measured and sent for histopathological evaluation. The weight, volume, survival rates of the grafts, the number of viable cells with the MTT test and pathological parameters, inflammation, vascularization, fibrosis, lipogranuloma and cyst formation, were evaluated.

RESULTS

Statistically significant differences were found between the groups in survival rates (p<0.05). In paired comparisons between the groups, the parameters of viable cells and survival rates were statistically significantly higher in apocynin group compared to the other groups (p<0.05). The survival rates relating to the weight and viable cell count in the DMSO group were statistically significantly higher than in the control group (p<0.05). However, no statistically significant difference was found between the DMSO group and the control group in the survival rate in terms of volume (p<0.05). There was no significant difference between the groups in the comparison of pathological parameters (p>0.05).

CONCLUSIONS

Apocynin increases fat graft survival in the animal fat grafting model. Therefore, apocynin can be used as an effective medical agent to prevent the volume loss of fat grafts.

NO LEVEL ASSIGNED

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Impact of Fat Graft Thickness and Harvesting Technique on Adipocyte Viability in a New Porcine Experimental Model: An Immunohistochemical Analysis

BACKGROUND

Autologous fat grafting (AFG) has been employed in surgical practice as a filling method. However, controversies remain on the specifics of this technique. So far, few relevant experimental large animal studies have objectively assessed factors related to AFG integration.

OBJECTIVES

This study utilized an experimental, medium-sized animal model to compare the feasibility of AFG collected employing 2 different techniques with instruments of distinct thicknesses.

METHODS

Twenty minipigs (Sus scropha domesticus) were subjected to AFG harvesting via en bloc resection utilizing 3- (Group I) and 5-mm-diameter (Group II) round punch blades (PBs) and liposuction (LS) with 3- (Group III) and 5-mm-diameter cannulas (Group IV). Both samples were grafted intramuscularly (biceps femoralis). Hematoxylin and eosin staining was employed to identify intact adipocytes, fat necrosis, fibrosis, inflammation, and oil cysts. Immunohistochemical staining (perilipin-A, tumor necrosis factor alfa, and cluster of differentiation number 31) was utilized to quantify the feasibility of adipocytes, tissue necrosis, and neoangiogenesis, respectively.

RESULTS

Hematoxylin and eosin analysis showed that fat necrosis and histiocyte presence were significantly lower in the AFG harvested utilizing a PB than in LS. For perilipin-A, a statistical difference was observed between subgroups I and III (P = 0.001) and I and IV (P = 0.004). Instrument diameter had no effect on graft integration in comparisons between groups II and III (P = 0.059) and II and IV (P = 0.132).

CONCLUSIONS

In this experimental study, fat collected utilizing a PB demonstrated higher adipocyte viability than fat collected with LS. The diameter of the collection instruments, whether PB or LS, had no effect on graft integration.

Human Adipose Tissue Derived Extracellular Matrix and Methylcellulose Hydrogels Augments and Regenerates the Paralyzed Vocal Fold

Vocal fold paralysis results from various etiologies and can induce voice changes, swallowing complications, and issues with aspiration. Vocal fold paralysis is typically managed using injection laryngoplasty with fat or synthetic polymers. Injection with autologous fat has shown excellent biocompatibility. However, it has several disadvantages such as unpredictable resorption rate, morbidities associated with liposuction procedure which has to be done in operating room under general anesthesia. Human adipose-derived extracellular matrix (ECM) grafts have been reported to form new adipose tissue and have greater biostability than autologous fat graft. Here, we present an injectable hydrogel that is constructed from adipose tissue derived soluble extracellular matrix (sECM) and methylcellulose (MC) for use in vocal fold augmentation. Human sECM derived from adipose tissue was extracted using two major steps—ECM was isolated from human adipose tissue and was subsequently solubilized. Injectable sECM/MC hydrogels were prepared by blending of sECM and MC. Sustained vocal fold augmentation and symmetric vocal fold vibration were accomplished by the sECM/MC hydrogel in paralyzed vocal fold which were confirmed by laryngoscope, histology and a high-speed imaging system. There were increased number of collagen fibers and fatty granules at the injection site without significant inflammation or fibrosis. Overall, these results indicate that the sECM/MC hydrogel can enhance vocal function in paralyzed vocal folds without early resorption and has potential as a promising material for injection laryngoplasty for stable vocal fold augmentation which can overcome the shortcomings of autologous fat such as unpredictable duration and morbidity associated with the fat harvest.

Histological findings of an autologous dermal fat graft implanted onto the pectoralis major muscle of a rat model

Background

The aim of this study was to investigate the maintenance of volume as a spacer by comparing vascular supply and apoptosis in an implanted autologous-free dermal fat graft (FDFG) and free fat graft (FFG). An autologous FDFG is a material used in plastic surgery and oncoplastic breast surgery that is ideal for immediate volume replacement after partial mastectomy because of its easy availability and minimal invasion of the donor site; however, immunohistochemical findings and survival procedures have not yet been reported.

Methods

An experimental protocol using a unique animal model was designed for the present study. The expression of vascular endothelial growth factor (VEGF) was measured in FDFGs and FFGs implanted onto the pectoral major muscle of Wistar rats. Thirty Wistar rats were divided into two groups and postoperatively 1, 2, 4, 8, and 16 weeks (POW1, 2, 4, 8, 16). Six samples from three rats in each group were used as control samples (POW0).

Results

The thickness of the implanted FDFG was not significantly different from the control sample at POW1, 2, 4, 8, and 16 between FDFG and FFG group; however, the thickness at POW8 and 16 was significantly lesser in the FFG group than in the control samples.

The average proportion of fatty tissue to whole tissue ranged from 34.2 to 48.6 % in the FDFG group and from 57.2 to 76.7 % in the FFG group during the observation period; however, there was no significant difference in the proportion of fatty tissue between these two groups. There were no significant differences between the average number of VEGF-positive cells in the FDFG group and the FFG group at POW1, 2, 4, 8, and 16. The average number of TUNEL-positive cells in the early period at POW1 was significantly lower in the FDFG group than in the FFG group.

Conclusions

This rat model was useful for investigating the mechanisms of angiogenesis, apoptosis, structure maintenance, and fibromatous changes. From the present experimental study, we believe that FDFG is one of the most convenient materials currently available to repair small defects at the time of BCS even in the clinical field.