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.

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>

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>

Literature mining and bioinformatic analysis of dysregulated genes in hypertrophic scar / 中华整形外科杂志

<p><b>OBJECTIVE</b>To explore the pathogenesis mechanism of hypertrophic scar (HS) and the effective means for its clinical treatment, the difference of the gene expressions between HS and normal skin was compared.</p><p><b>METHODS</b>The differentially expressed genes between HS and normal skin were obtained by mining PubMed. The dysregulated genes in HS were analyzed by a series of bioinformatics methods, including protein-protein interaction networks, pathways, Gene Ontology and functional annotation clustering analysis.</p><p><b>RESULTS</b>A total of 55 dysregulated genes in HS was identified (46 up-regulated genes and 9 down-regulated genes). Fifty-one genes were found to encode proteins with interaction network, including up-regulated genes TGFB1, FN1, JUN, COL1A1, CTGF, VEGFA, FOS, COL3A1, IGF1, IL4, PELO, SMAD2, TIMP1, PCNA, and ITGA4 and down-regulated genes ITGB1 and DCN as the central nodes for this network. The dysregulated genes in HS involved in a variety of biological pathways, such as focal adhesion formation, integrin signal transduction, and tumor formation. Furthermore, the dysregulated genes in HS played the important roles in biological processes of cell surface receptor linked signal transduction, tissue development, cell proliferation and apoptosis, and macromolecule biosynthetic process, as well as in molecular function of calcium ion binding, double-stranded DNA binding, heparin binding, promoter binding and MAP kinase activity. The results of functional annotation clustering analysis revealed that the dysregulated genes in HS involved in epidermis development, angiogenesis, and apoptosis.</p><p><b>CONCLUSION</b>Such key genes as TGFB1, FN1, and JUN, along with the pathways, biological processes and molecular functions involving epidermis development, angiogenesis, and extracellular matrix-integrin-focal adhesion signal transduction may play the important roles in the development of HS. The investigations of the dysregulated genes in HS could provide the new targets for clinical treatment.</p>

Inhibition of periostin gene expression via RNA interference suppressed the proliferation, apoptosis and invasion in U2OS cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Periostin originally designated osteoblast-specific factor 2 (OSF-2) is frequently found to be highly expressed in various types of human cancer cell lines in vitro and human cancer tissues in vivo. We proposed that periostin was a key factor during the process of proliferation and invasion in cancer cells. We investigated the effect of periostin on the function of human osteosarcoma cell line (U2OS), such as proliferation, apoptosis, invasion and the associated signal pathway.</p><p><b>METHODS</b>A human PGCsi/U6 promoter-driven DNA template was adopted to induce short hairpin RNA (shRNA)-triggered RNA interference (RNAi) to block periostin gene expression in the cell line U2OS. U2OS cells were divided into three groups: cells transfected with phosphate buffered saline as control group (the U2OS group), cells transfected with pGCsi as negative control group (the NC group) and cells transfected with periostin/pGCsi as experimental group (the pGCsi-periostin group). Then, transfection efficiency of cell was observed under fluorescent microscope. The expressions of periostin and the related genes in cells were detected by reverse transcription polymerase chain reaction and Western Blotting. Cell viability was determined using the methyl-thiazolyl tetrazolium bromide (MTT) quantitative colorimetric assay. The invasion and migration capability of cells were tested by transwell plates with or without extracellular matrix gel. Furthermore, the changes of cell cycle and apoptosis were analyzed by flow cytometry.</p><p><b>RESULTS</b>The transfection efficiency of periostin/pGCsi to U2OS cells was about 70% - 80%. When compared with the NC group, the levels of mRNA and protein of periostin in the pGCsi-periostin group decreased by 82% (F = 564.71, P < 0.001) and 58% (F = 341.51, P < 0.001), respectively. Meantime, the earlier apoptosis value increased by 417% (F = 28.69, P < 0.001). The percentage of S phase pGCsi-periostin cells decreased by 21% (F = 47.00, P < 0.001), however, that of G0 - G1 phase cells increased by 12% (F = 14.50, P < 0.001). The capability of migration and invasion reduced by 41% (F = 17.79, P < 0.001) and 72% (F = 197.08, P < 0.001), respectively. The cell proliferation in the pGCsi-periostin group decreased by 59% and 72% at 48 and 120 hours after transfection, respectively. The mRNA expressions of transforming growth factor-β and vascular endothelial growth factor decreased by 17% (F = 73.99, P < 0.001) and 47% (F = 30.25, P < 0.001), respectively. A tendency of lower focal adhesion kinase (FAK) was shown in pGCsi-periostin cells but without any statistically significant difference. Otherwise the expression of p-FAK in those cells had markedly decreased by 21% (F = 16.81, P < 0.001).</p><p><b>CONCLUSIONS</b>RNAi against periostin can effectively down-regulate periostin gene expression. Periostin increases the hyperplasia and invasion of cancer cells. Periostin might be involved in and served as a tumor promoter gene in the pathogenesis of osteosarcoma.</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>