• Journal of Chest Surgery
• /
• v.37 no.4
• /
• pp.297-306
• /
• 2004

Current artificial heart valves have several disadvantages, such as thromboembolism, limited durability, infection, and inability to grow. The solution to these problems would be to develop a tissue-engineered heart valves containing autologous cells. The aim of this study was to optimize the protocol to obtain a porcine acellular matrix and seed goat autologous endothelial cells on it, and to evaluate the biological responses of xenograft and xeno-autograft heart valves in goats. Material and Method: Fresh porcine pulmonic valves were treated with one method among 3 representative decellularization protocols (Triton-X, freeze-thawing, and NaCl-SDS). Goat venous endothelial cells were isolated and seeded onto the acellularized xenograft leaflets. Microscopic examinations were done to select the most effective method of decellularizing xenogeneic cells and seeding autologous endothelial cells. Two pulmonic valve leaflets of. 6 goats were replaced by acellularized porcine leaflets with or without seeding autologous endothelial cells while on cardiopulmonary bypass. Goats were sacrificed electively at 6 hours, 1 day, 1 week, 1 month, 3 months, and 6. months after operation. Morphologic examinations were done to see the biological responses of replaced valve leaflets. Result: The microscopic examinations showed that porcine cells were almost completely removed in the leaflets treated with NaCl-SDS. The seeded endothelial cells were more evenly preserved in NaCl-SDS treatment. All 6 goats survived the operation without complications. The xeno- autografts and xenografts showed the appearance, the remodeling process, and the cellular functions of myofibroblasts, 1 day, 1 month, and 3 months after operation, respectively. They were compatible with the native pulmonary leaflet (control group) except for the increased cellularity at 6 months. The xenografts revealed the new endothelial cell lining at that time. Conclusion: Treatment with NaCl-SDS was most effective in obtaining decellularized xenografts and facilitate seeding autologous endothelial cells. The xenografts and xeno-autografts were repopulated with myofibroblasts and endothelial cells in situ serially. Both of grafts served as a matrix for a tissue engineered heart valve and developed into autologous tissue for 6 months.

• Tuberculosis and Respiratory Diseases
• /
• v.79 no.3
• /
• pp.143-152
• /
• 2016

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal lung disease characterized by the accumulation of excessive fibroblasts and myofibroblasts in the extracellular matrix. The transforming growth factor ${\beta}1$ (TGF-${\beta}1$)-induced epithelial-to-mesenchymal transition (EMT) is thought to be a possible source of fibroblasts/myofibroblasts in IPF lungs. We have previously reported that apolipoprotein A1 (ApoA1) has anti-fibrotic activity in experimental lung fibrosis. In this study, we determine whether ApoA1 modulates TGF-${\beta}1$-induced EMT in experimental lung fibrosis and clarify its mechanism of action. Methods: The A549 alveolar epithelial cell line was treated with TGF-${\beta}1$ with or without ApoA1. Morphological changes and expression of EMT-related markers, including E-cadherin, N-cadherin, and ${\alpha}$-smooth muscle actin were evaluated. Expressions of Smad and non-Smad mediators and TGF-${\beta}1$ receptor type 1 ($T{\beta}RI$) and type 2 ($T{\beta}RII$) were measured. The silica-induced lung fibrosis model was established using ApoA1 overexpressing transgenic mice. Results: TGF-${\beta}1$-treated A549 cells were changed to the mesenchymal morphology with less E-cadherin and more N-cadherin expression. The addition of ApoA1 inhibited the TGF-${\beta}1$-induced change of the EMT phenotype. ApoA1 inhibited the TGF-${\beta}1$-induced increase in the phosphorylation of Smad2 and 3 as well as that of ERK and p38 mitogen-activated protein kinase mediators. In addition, ApoA1 reduced the TGF-${\beta}1$-induced increase in $T{\beta}RI$ and $T{\beta}RII$ expression. In a mouse model of silica-induced lung fibrosis, ApoA1 overexpression reduced the silica-mediated effects, which were increased N-cadherin and decreased E-cadherin expression in the alveolar epithelium. Conclusion: Our data demonstrate that ApoA1 inhibits TGF-${\beta}1$-induced EMT in experimental lung fibrosis.

• Journal of Life Science
• /
• v.21 no.12
• /
• pp.1795-1803
• /
• 2011

Non-alcoholic fatty liver disease accompanies the rise in the prevalence of obesity, diabetes and the tendency toward high-fat dietary habits. Specifically, the higher prevalence of non-alcoholic fatty liver disease in men and postmenopausal women seems to be caused by the protective effects of estrogen against liver fibrosis, or lack thereof. There are no effective preventive therapies for liver diseases because the mechanisms underlying the progression of fatty liver diseases to chronic liver diseases and the protective effects of estrogen against fibrogenesis remain unclear. Recently, it has been reported that the hedgehog signaling pathway plays an important role in the progression of chronic liver diseases. Hedgehog, a morphogen regulating embryonic liver development, is expressed in injured livers but not in adult healthy livers. The level of hedgehog expression parallels the stages of liver diseases. Hedgehog induces myofibroblast activation and hepatic progenitor cell proliferation and leads to excessive liver fibrosis, whereas estrogen inhibits the activation of hepatic stellate cells to myofibroblasts and prevents liver fibrosis. Although the mechanism underlying the opposing actions of hedgehog and estrogen on liver fibrosis remain unclear, the suppressive effects of estrogen on the expression of osteopontin, a profibrogenic extracellular matrix protein and cytokine, and the inductive effects of hedgehog on osteopontin transcription suggest that estrogen and hedgehog are associated with liver fibrosis regulation. Therefore, further research on the estrogen-mediated regulatory mechanisms underlying the hedgehog-signaling pathway can identify the mechanism underlying liver fibrogenesis and contribute to developing therapies for preventing the progression of fibrosis to chronic liver diseases.

• International Journal of Stem Cells
• /
• v.16 no.1
• /
• pp.52-65
• /
• 2023

Background and Objectives: Epithelial-Mesenchymal transition (EMT) is one of the origins of myofibroblasts in renal interstitial fibrosis. Mesenchymal stem cells (MSCs) alleviating EMT has been proved, but the concrete mechanism is unclear. To explore the mechanism, serum-free MSCs conditioned medium (SF-MSCs-CM) was used to treat rat renal tubular epithelial cells (NRK-52E) fibrosis induced by transforming growth factor-β1 (TGF-β1) which ameliorated EMT. Methods and Results: Galectin-3 knockdown (Gal-3 KD) and overexpression (Gal-3 OE) lentiviral vectors were established and transfected into NRK-52E. NRK-52E fibrosis model was induced by TGF-β1 and treated with the SF-MSCs-CM for 24 h after modelling. Fibrosis and autophagy related indexes were detected by western blot and immunocytochemistry. In model group, the expressions of α-smooth muscle actin (α-SMA), fibronectin (FN), Galectin-3, Snail, Kim-1, and the ratios of P-Akt/Akt, P-GSK3β/GSK3β, P-PI3K/PI3K, P-mTOR/mTOR, TIMP1/MMP9, and LC3B-II/I were obviously increased, and E-Cadherin (E-cad) and P62 decreased significantly compared with control group. SF-MSCs-CM showed an opposite trend after treatment compared with model group. Whether in Gal-3 KD or Gal-3 OE NRK-52E cells, SF-MSCs-CM also showed similar trends. However, the effects of anti-fibrosis and enhanced autophagy in Gal-3 KD cells were more obvious than those in Gal-3 OE cells. Conclusions: SF-MSCs-CM probably alleviated the EMT via inhibiting Galectin-3/Akt/GSK3β/Snail pathway. Meanwhile, Gal-3 KD possibly enhanced autophagy via inhibiting Galectin-3/Akt/mTOR pathway, which synergistically ameliorated renal fibrosis. Targeting galectin-3 may be a potential target for the treatment of renal fibrosis.

• Radiation Oncology Journal
• /
• v.28 no.1
• /
• pp.32-38
• /
• 2010

Purpose: Although radiation-induced fibrosis is one of the common sequelae occurring after irradiation of skin and soft tissues, the treatment methods are not well standardized. This study aimed to establish the skin fibrosis mouse model by fractionated radiation for the further mechanism studies or testing the efficacy of therapeutic candidates. Materials and Methods: The right hind limbs of BALB/c mice received two fractions of 20 Gy using a therapeutic linear accelerator. Early skin damages were scored and tissue fibrosis was assessed by the measurement of a leg extension. Morphological changes were assessed by H&E staining and by Masson's Trichrome staining. TGF-${\beta}1$ expression from soft tissues was also detected by immunohistochemistry and PCR. Results: Two fractions of 20 Gy irradiation were demonstrated as being enough to induce early skin damage effects such as erythema, mild skin dryness, dry and wet desquamation within several weeks of radiation. After 13 weeks of irradiation, the average radiation-induced leg contraction was $11.1{\pm}6.2mm$. Morphologic changes in irradiated skin biopsies exhibited disorganized collagen and extracellular matrix fibers, as well as the accumulation of myofibroblasts compared to the non-irradiated skin. Moreover, TGF-${\beta}1$ expression in tissue was increased by radiation. Conclusion: These results show that two fractions of 20 Gy irradiation can induce skin fibrosis in BALB/c mice accompanied by other common characteristics of skin damages. This animal model can be a useful tool for studying skin fibrosis induced by radiation.

• Journal of Chest Surgery
• /
• v.43 no.4
• /
• pp.356-363
• /
• 2010

Background: Connexin 43-mediated gap junctional communication plays an important role in atherosclerosis. Numerous studies have demonstrated a correlation between mitral valve annular calcification and atherosclerotic disease. However, the relevance of connexin 43 to mitral valve disease remains unclear. We hypothesized that the mechanism contributing to mitral valve disease is associated with alterations in cell-to-cell communication mediated by changes in Connexin 43 expression. Material and Method: Twenty male New Zealand rabbits were divided into two groups: animals in group 1 (n=10) were fed a normal chow diet, whilst those in group 2 (n=10) received a diet containing 1% cholesterol for 12 weeks. After sacrificing the animals, the mitral valves were excised and analyzed with immunohistochemical staining and Real-time Reverse Transcriptase polymerase chain reaction (real time RT-PCR). Result: Myofibroblasts and macrophages were found concentrated within the endothelial layer on the ventricular side of the leaflet in the cholesterol diet group. Immunohistochemial staining showed elevated expression of connexin43 in the cholesterol diet group. Real-time RT-PCR revealed increased connexin43 mRNA levels in mitral valves from hypercholesterolemic animals. Conclusion: Our finding that connexin43 expression is increased in mitral valves of hypercholesterolemic rabbits suggests that alterations in cell-to-cell communication via connexin43 containing gap junctions play a role in the development of mitral valve disease in hypercholesterolemia.

• Journal of Chest Surgery
• /
• v.41 no.6
• /
• pp.687-694
• /
• 2008

Background: Although aortic valve sclerosis causes no significant hemodynamic alterations, it is associated with an increased risk of cardiovascular death and myocardial infarction. However, the role of ${\beta}_3$ integrin in aortic valve sclerosis remains unclear. Material and Method: Twenty male New Zealand rabbits were divided into two groups. Group 1 rabbits (n=10) received a normal chow diet, while group 2 (n=10) rabbits received a diet containing 1% cholesterol for 12 weeks. After the rabbits were euthanized, their aortic valves and ascending aortas were excised for analysis. Result: Total serum cholesterol ($2,148.3{\pm}1,012.5\;mg/dL$ versus $53.7{\pm}31.8\;mg/dL$, p<0.05), triglyceride ($240.4{\pm}218.3\;mg/dL$ versus $31.6{\pm}6.4\;mg/dL$, p<0.05), and low density lipoprotein (LDL)-cholesterol($2,065.3{\pm}960.9\;mg/dL$ versus $29.1{\pm}30.9\;mg/dL$, p<0.05) levels were significantly higher in the cholesterol diet group compared with the normal diet group. Myofibroblasts and macrophages were more highly expressed in the aortic valve leaflets of rabbits in the cholesterol diet group than of those in the normal diet group. A real-time polymerase chain reaction revealed decreased ${\beta}_3$ integrin mRNA levels in the hypercholesterolemic aortic valves and aortas. Conclusion: The present study shows that hypercholesterolemia induces aortic valve sclerosis. These findings suggest that alterations in ${\beta}_3$ integrin may playa role in the development of aortic valve sclerosis.

• Tuberculosis and Respiratory Diseases
• /
• v.53 no.3
• /
• pp.309-318
• /
• 2002

Background : Usual interstitial pneumonia (UIP) is a fatal progressive fibrotic disorder of the lung with unknown etiology and characterized by a poor response to conventional immunosuppressive therapy. The histologic hallmark of UIP is parchy distribution of subpleural fibrosis and fibroblastic foci(FBF) with interposed normal appearing lung. Because FBF is a collection of actively proliferating myofibroblasts, it can be a marker of activity and prognosis of UIP. However, there were contradictory reports about the correlation between the degree of FBF and survival. Therefore we performed this study to investigate the value of FBF as prognostic marker of UIP. Methods : This was a retrospective study on the 46 patients(M:F=33:13, mean age:$59{\pm}12$ years) with UIP diagnosed by the surgical lung biopsy at the Asan Medical Center, Seoul, Korea between 1990 and 2000 and had follow-up of more than a year. All the biopsy specimens were reevaluated and diagnosed as UIP according to the ATS/ERS classification. Semiquantitative grading of FBF(absent, 0; mild 1; moderate 2; marked 3) by the experienced pathologists who did not know the clinical findings were compared to the clinical data and the follow up course. Results : Thirteen patients(28.2%) died of UIP progression during the study period. The median survival time of all the subjects was 26 months after the biopsy. At the univariate analysis, FVC, $D_Lco$, smoking history and the grade of FBF were significantly related to the survial. The survival was longer in subjects with lesser degrees of FBF, higher DLco, higher FVC and history of smoking. However the multivariate analysis with Cox regression test showed the extent of FBF was the only independent prognostic marker of UIP. Conclusion : These data suggested that the extent of FBF on the surgical lung biopsy can be used as a prognostic marker of UIP.

• Journal of Life Science
• /
• v.23 no.5
• /
• pp.710-720
• /
• 2013

Radiotherapy is commonly used in treating many kinds of cancers which cannot be cured by other therapeutic strategies. However, radiotherapy also induces the damages on the normal tissues. Radiation-induced fibrosis is frequently observed in the patients undergoing radiotherapy, and becomes a major obstacle in the treatment of intrahepatic cancer. Hedgehog (Hh) that is an essential in the liver formation during embryogenesis is not detected in the healthy liver, but activated and modulates the repair process in damaged livers in adult. The expression of Hh increases with the degree of liver damage, regulating the proliferation of hepatic progenitors and hepatic stellate cells (HSC). In addition, Hh induces epithelial-to-mesencymal transition (EMT) and activation of myofibroblasts. In the irradiated livers, up-regulated expression of Hh signaling was associated with proliferation of progenitors, EMT induction, and increased fibrosis. Female-specific expression of Hh leaded to the expansion of progenitors and the accumulation of collagen in the irradiated livers of female mice, indicating that gender disparity in Hh expression may be related with radiation-susceptibility in female. Hence, Hh signaling becomes a novel object of studies for fibrogenesis induced by radiation. However, the absence of the established experimental animal models showing the similar physiopathology with human liver diseases and fibrosis-favorable microenvironment hamper the studies for the radiation-induced fibrosis, providing a few descriptive results. Therefore, further research on the association of Hh with radiation-induced fibrosis can identify the cell and tissue-specific effects of Hh and provides the basic knowledge for underlying mechanisms, contributing to developing therapies for preventing the radiation-induced fibrosis.

• Tuberculosis and Respiratory Diseases
• /
• v.51 no.6
• /
• pp.540-549
• /
• 2001

Background : Usual interstitial pneumonia (UIP) is a progressive fibrous lung disease with occasional fatal outcomes. However, the extent and rate of progression varies markedly from one patient to another. As a result, it is difficult to determine the time of the initial treatment and assess the disease activity and course. Fibroblast foci (FF) is well known to synthesize collagen actively by their myofibroblasts component. However, the prognostic value of the FF have not been evaluated in patients with VIP. Therefore this study was undertaken to determine how the number of fibroblastic foci can reflect the disease activity and progression. Methods: Twenty patients with UIP(M : F=13 : 7), who were diagnosed by a surgical lung biopsy. The number of fibroblastic foci was analyzed in terms of its correlation with the clinical manifostations, pulmonary function test, arterial blood gas analysis, and a bronchoalveolar lavage(BAL). Results : The number of fibroblastic foci did not correlate with the various lung function tests and the other clinical parameters. Interestingly, the percentage of neutrophils in the bronchoalveolar lavage fluid did correlate with the quantity of the normalized Vv of FF(r=0.60, p<0.05). The patients were divided into 2 groups, group I and II, arbitrarily, according to the value of the normalized Vv. The clinical parameters and the PIT results were not different between the two groups. In particular, the survival rate between the two groups according to the Kaplan-Meier analysis were not different. Conclusion : A large number of FF does not imply a bad prognosis in patients with UIP.