Flow Perfusion Maintaining Long-term Viability of the Rat Groin Fat Flap: A Novel Model for Research on Large-scale Engineered Tissues / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Large-scale muscle tissue engineering remains a major challenge. An axial vascular pedicle and perfusion bioreactor are necessary for the development and maintenance of large-scale engineered muscle to ensure circulation within the construct. We aimed to develop a novel experimental model of a large-scale engineered muscle flap from an existing rat groin fat flap.</p><p><b>METHODS</b>A fat flap based on the superficial inferior epigastric vascular pedicle was excised from rats and placed into a perfusion bioreactor. The flaps were kept in the bioreactor for up to 7 weeks, and transdifferentiation of adipose to muscle tissue could have taken place. This system enabled myogenic-differentiation medium flow through the bioreactor at constant pH and oxygen concentration. Assessment of viability was performed by an immunofluorescence assay, histological staining, a calcein-based live/dead test, and through determination of RNA quantity and quality after 1, 3, 5, and 7 weeks.</p><p><b>RESULTS</b>Immunofluorescence staining showed that smooth muscle around vessels was still intact without signs of necrosis or atrophy. The visual assessment of viability by the calcein-based live/dead test revealed viability of the rat adipose tissue preserved in the bioreactor system with permanent perfusion. RNA samples from different experimental conditions were quantified by spectrophotometry, and intact bands of 18S and 28S rRNA were detected by gel electrophoresis, indicating that degradation of RNA was minimal.</p><p><b>CONCLUSIONS</b>Flow perfusion maintains the long-term viability of a rat groin engineered muscle flap in vitro, and a large-scale vascularized muscle could be engineered in a perfusion bioreactor.</p>

Basic and Clinical Evidence of an Alternative Method to Produce Vivo Nanofat / 中华医学杂志(英文版)

<p><b>Background</b>Fat grafting technologies are popularly used in plastic and reconstructive surgery. Due to its size limitation, it is hard to directly inject untreated fat tissue into the dermal layer. Nanofat, which was introduced by Tonnard, solves this problem by mechanically emulsifying fat tissue. However, the viability of the cells was greatly destroyed. In this study, we reported a new method by "gently" digesting the fat tissue to produce viable adipocytes, progenitors, and stromal stem cells using collagenase I digestion and centrifugation. This was named "Vivo nanofat".</p><p><b>Methods</b>Human liposuction aspirates were obtained from five healthy female donors with mean age of 28.7 ± 5.6 years. Colony-forming assay, flow cytometry analysis, and adipogenic and osteogenic induction of the adherent cells from the Vivo nanofat were used to characterize the adipose mesenchymal stem cells (MSCs). To investigate in vivo survival, we respectively injected Vivo nanofat and nanofat subcutaneously to the back of 8-week-old male BALB/c nude mice. Samples were harvested 2 days, 2 weeks, and 4 weeks postinjection for measurement, hematoxylin and eosin staining, and immunostaining.</p><p><b>Results</b>Our results showed that the Vivo nanofat contained a large number of colony-forming cells. These cells expressed MSC markers and had multi-differentiative potential. In vivo transplantation showed that the Vivo nanofat had lower resorption ratio than that of nanofat. The size of the transplanted nanofat was obviously smaller than that of Vivo nanofat 4 weeks postinjection (0.50 ± 0.17 cm vs. 0.81 ± 0.07 cm, t = -5783, P = 0.01).</p><p><b>Conclusion</b>Vivo nanofat may serve as a cell fraction injectable through a fine needle; this could be used for cosmetic applications.</p>

Flow Perfusion Maintaining Long-term Viability of the Rat Groin Fat Flap: A Novel Model for Research on Large-scale Engineered Tissues / 中华医学杂志(英文版)

BACKGROUND@#Large-scale muscle tissue engineering remains a major challenge. An axial vascular pedicle and perfusion bioreactor are necessary for the development and maintenance of large-scale engineered muscle to ensure circulation within the construct. We aimed to develop a novel experimental model of a large-scale engineered muscle flap from an existing rat groin fat flap.@*METHODS@#A fat flap based on the superficial inferior epigastric vascular pedicle was excised from rats and placed into a perfusion bioreactor. The flaps were kept in the bioreactor for up to 7 weeks, and transdifferentiation of adipose to muscle tissue could have taken place. This system enabled myogenic-differentiation medium flow through the bioreactor at constant pH and oxygen concentration. Assessment of viability was performed by an immunofluorescence assay, histological staining, a calcein-based live/dead test, and through determination of RNA quantity and quality after 1, 3, 5, and 7 weeks.@*RESULTS@#Immunofluorescence staining showed that smooth muscle around vessels was still intact without signs of necrosis or atrophy. The visual assessment of viability by the calcein-based live/dead test revealed viability of the rat adipose tissue preserved in the bioreactor system with permanent perfusion. RNA samples from different experimental conditions were quantified by spectrophotometry, and intact bands of 18S and 28S rRNA were detected by gel electrophoresis, indicating that degradation of RNA was minimal.@*CONCLUSIONS@#Flow perfusion maintains the long-term viability of a rat groin engineered muscle flap in vitro, and a large-scale vascularized muscle could be engineered in a perfusion bioreactor.

Biological characteristics of human adipose-derived stem cells and their response to periostin in vitro / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Many studies on periostin have focused on its role in tumors and vascular reconstruction. However, the effect of periostin on stem cell function remains unclear. The aim of this study was to enhance vitality in adipose-derived stem cells (ADSCs), the effect of periostin on the function of ADSCs was observed.</p><p><b>METHODS</b>Human ADSCs (hADSCs) were isolated from human adipose tissue by collagenase I digestion and collected in multi-periods for in vitro culture. CD29, CD34, CD44, CD45 and CD105 were detected by flow cytometry. In addition, directed differentiation of hADSCs was induced using adipogenic, osteogenic and chondrogenic induction mediums. The induced morphological changes were observed using oil red O, Alizarin red and alcian blue staining. Periostin was administered to hADSCs in an acidic environment. The treatments of cells were divided into three groups: a periostin group (P); an acidic control group (A); a normal group (N). Then the resulting cell proliferation and migration were detected using a Cell Counting Kit-8 (CCK-8) and a transwell chamber assay, respectively.</p><p><b>RESULTS</b>The detection rates of CD29, CD44, CD105, CD34 and CD45 were 98.89%, 93.73%, 86.99%, 0.19% and 0.16%. The specific staining of cells was positive after induction culture. The mean absorbance of the cells in group P and A at 12 hours were 16.67% and 22.22% greater than group N, respectively (P < 0.01). The mean absorbance of cells from group P was 20.00% greater than that of group A at 48 hours (P < 0.05). The mean number of migratory cells per visual field in group A was 50.38% lower than that in group N (P < 0.05). The migratory cell number in group P was 119.98% greater than that in group A (P < 0.05).</p><p><b>CONCLUSIONS</b>The acidic environment impacted hADSC proliferation and inhibited cell migration. However, periostin was able to promote the proliferation and migration of hADSCs despite the acidic environment.</p>

The expression of fibrillin 1 in pathologic scars and its significance / 中华整形外科杂志

<p><b>OBJECTIVE</b>To probe into the mechanism of fibrillin 1 in pathologic scar, by examining the expressions of fibrillin 1 and TGF-beta1 as well as their correlations in the tissues of keloid, hypertrophic scar and normal skin.</p><p><b>METHODS</b>The tissues of keloid, hypertrophic scar and normal skin were tested. RT-PCR was used to assess the mRNA expression levels of the aimed genes. The distribution of fibrillin 1 in scars and normal skin was examined by immunohistochemistry staining.</p><p><b>RESULTS</b>The mRNA level of fibrillin 1 in keloid (0.802 +/- 0.116) was increased by 218.25% (P < 0.01) than that in normal skin (0.252 +/- 0.067). The expression of the gene in hypertrophic scar (0.628 +/- 0.144) was higher by 149.21% (while, P > 0.05) than that in normal skin. The expression of TGF-beta1 in keloid and hypertrophic scar were more than that in normal skin. The expression of fibrillin 1 was related to that of TGF-beta1 positively (r = 0.820, P < 0.01). Fibrillin 1 protein was stained positively in basic membranes, endothelial cells, fibroblasts and extracellular matrix of skin tissues. In dermal, the protein levels of fibrillin 1 in keloid (0.117 +/- 0.042) was decreased than those in normal skin (0.185 +/- 0.043) and hypertrophic scar (0.181 +/- 0.048), the inhibition rates were 36.76%, 35.36% respectively (both P < 0.01).</p><p><b>CONCLUSIONS</b>The expression of fibrillin 1 in keloid was changed and related to the expression of TGF-beta1 positively, which appears that fibrillin 1 was a cicatrix specific gene. Fibrillin 1 might play an important role in the formation of keloid.</p>

The expression of periostin in hyperplasic scars and the relations to TGF-beta1 and its receptors / 中华整形外科杂志

<p><b>OBJECTIVE</b>To probe into periostin's role in the pathological mechanism of hyperplasic scars, by examining the expression of periostin in hyperplasic scar tissues. To investigate the correlations between periostin and TGF-beta1, TGF-beta R I, TGF-beta R II.</p><p><b>METHODS</b>RT-PCR was used to assess the mRNA expression levels of TGF-beta1, TGF-beta R I, TGF-beta R II in three kinds of tissues, which are keloid (K), hypertrophic scar (HS) and normal skin (SK). The protein expression of periostin was measured with Western blotting.</p><p><b>RESULTS</b>The mRNA level of periostin in K was higher than that in SK. The mRNA expression of TGF-beta1 in K was higher than that in HS and SK. The mRNA level of TGF-beta R I in K was higher than that in HS and SK. The significances above all was at P < 0.01. The protein expression level of periostin in HS increased, compared with that in SK (P < 0.05). Periostin was related to TGF-beta1 positively (P <0.01).</p><p><b>CONCLUSIONS</b>The periostin's expression is increased in keloids. Periostin is a cicatrix specific gene. Periostin appears to play an important role in the formation of keloids, which is related to TGF-beta1 closely.</p>