Preparation and characterization of a novel humanized collagen III with repeated fragments of Gly300-Asp329

Recombinant human collagens have attracted intensive interest in the past two decades, demonstrating considerable potential in medicine, tissue engineering, and cosmetics. Several humanized recombinant collagens have been produced, exhibiting similar characteristics as the native species. To get insight into the structural and bioactive properties of different parts of collagen, in this study, the segment of Gly300-Asp329 of type III collagen was first adopted and repeated 18 times to prepare a novel recombinant collagen (named rhCLA). RhCLA was successfully expressed in E. coli, and a convenient separation procedure was established through reasonably combining alkaline precipitation and acid precipitation, yielding crude rhCLA with a purity exceeding 90%. Additionally, a polishing purification step utilizing cation exchange chromatography was developed, achieving rhCLA purity surpassing 98% and an overall recovery of approximately 120 mg/L culture. Simultaneously, the contents of endotoxin, nucleic acids, and host proteins were reduced to extremely low levels. This fragmented type III collagen displayed a triple-helical structure and gel-forming capability at low temperatures. Distinct fibrous morphology was also observed through TEM analysis. In cell experiments, rhCLA exhibited excellent biocompatibility and cell adhesion properties. These results provide valuable insights for functional studies of type III collagen and a reference approach for the large-scale production of recombinant collagens.

RNAi nanotherapy for fibrosis: highly durable knockdown of CTGF/CCN-2 using siRNA-DegradaBALL (LEM-S401) to treat skin fibrotic diseases

Skin fibrosis occurs in a variety of human diseases but the current anti-fibrosis treatments are not sufficient. One major cause of fibrotic diseases shared across diverse organ fibrosis is uncontrolled overexpression of the connective tissue growth factor (CTGF, also known as CCN2). Here, we examine the anti-fibrotic activity of RNAi therapy utilizing siRNA against CTGF with a new drug delivery system (DDS), 'DegradaBALL', which is based on porous nanoparticles, for durable CTGF gene silencing. DegradaBALL is a modular DDS having many favorable properties for RNA delivery such as effective intracellular uptake, convenient drug loading, biocompatibility, sustained release profile and biodegradability. DegradaBALL loaded with siCTGF, named 'LEM-S401', showed highly durable and effective CTGF gene-silencing in TGF-β induced lung fibrosis and skin fibrosis model cells, A549 and HaCaT, respectively. In addition, LEM-S401 induced knockdown of collagen types I and III, which are excess extracellular matrix components in fibrotic skin in addition to CTGF in the mouse wound healing model. Most importantly, we showed that LEM-S401 effectively inhibited the formation of hypertrophic scars in wound-associated dermal fibrosis mouse models, during both the epidermis recovery and tissue remodeling process. Our findings suggest that LEM-S401 could be a highly potent therapeutic option for skin fibrotic diseases.

Exogenous growth factors enhance the expression of cola1, cola3, and Elastin in fibroblasts via activating MAPK signaling pathway

Exogenous growth factors could accelerate the process of wound healing. However, the underlying mechanisms have not been clearly clarified. The aim of the present study was to investigate the effect of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) on the expression of type I collagen (cola1), type III collagen (cola3), and Elastin in fibroblasts, which are widely expressed in fibroblasts and promote the function of fibroblasts. We measured the levels of cola1 and cola3 in human fibroblast cells cultured in medium containing EGF or bFGF at concentrations ranging from 0.1 to 1000 μg/L by Western blotting and RT-PCR assays, and found that EGF or bFGF enhanced the expression of cola1 and cola3 in a concentration-dependent manner. We further discovered that after stimulation with EGF or bFGF in human fibroblast cells, mitogen-activated protein kinases (MAPK) family members were generally activated, whose expression trend was consistent with that of cola1, cola3, and Elastin. In summary, in this study, we uncovered that exogenous growth factors enhance the expression of cola1, cola3, and Elastin, which is probably regulated via activating MAPK signaling pathway.

Homemade-device-induced negative pressure promotes wound healing more efficiently than VSD-induced positive pressure by regulating inflammation, proliferation and remodeling

Vacuum sealing drainage (VSD) is an effective technique used to promote wound healing. However, recent studies have shown that it exerts positive pressure (PP) rather than negative pressure (NP) on skin. In this study, we created a homemade device that could maintain NP on the wound, and compared the therapeutic effects of VSD-induced PP to those of our homemade device which induced NP on wound healing. The NP induced by our device required less time for wound healing and decreased the wound area more efficiently than the PP induced by VSD. NP and PP both promoted the inflammatory response by upregulating neutrophil infiltration and interleukin (IL)‑1β expression, and downregulating IL‑10 expression. Higher levels of epidermal growth factor (EGF), transforming growth factor (TGF)‑β and platelet-derived growth factor (PDGF), and lower levels of basic fibroblast growth factor (bFGF) were observed in the wound tissue treated with NP compared to the wound tissue exposed to PP. Proliferation in the wound tissue exposed to NP on day 10 was significantly higher than that in wound tissue exposed to PP. NP generated more fibroblasts, keratinized stratified epithelium, and less epithelia with stemness than PP. The levels of ccollagen Ⅰ and Ⅲ were both decreased in both the NP and PP groups. NP induced a statistically significant increase in the expression of fibronectin (FN) on days 3 and 10 compared to PP. Furthermore, the level of matrix metalloproteinase (MMP)‑13 increased in the NP group, but decreased in the PP group on day 3. NP also induced a decrease in the levels of tissue inhibitor of metalloproteinase (TIMP)‑1 and TIMP‑2 during the early stages of wound healing, which was significantly different from the increasing effect of PP on TIMP‑1 and TIMP‑2 levels at the corresponding time points. On the whole, our data indicate that our homemade device which induced NP, was more efficient than VSD‑induced PP on wound healing by regulating inflammation, secretion, proliferation and the distribution of different cells in wound tissue.

Collagen I and III, MMP-1 and TIMP-1 immunoexpression in dilated cardiomyopathy

The extracellular matrix (ECM) remodeling represents the pathological substrate of dilated cardiomyopathy (DCM). In this study, we statistically analyzed the immunoexpression of collagen I and III, matrix metalloproteinase-1 (MMP-1) and its tissue inhibitor-1 (TIMP-1) in the myocardial tissue in 18 cases of DCM compared to a control group. We observed a significant increase in the immunoexpression of collagen I and III in patients with DCM and a significant reduction in the immunoexpression of MMP-1 compared with the control group. Also, the collagen I and TIMP-1 expression indicated a positive linear correlation and respectively a negative linear relationship with collagen III and MMP-1. The analyzed markers in this study can be used to quantify the degree of collagen sclerosis from the ECM of DCM.

THE INFLUENCE OF VITAMIN C ON THE DYNAMIC OF RELATION OF COLLAGEN I AND III TYPES IN THE PERIPROSTHESIS AREA

The aim of the study was to learn the degree of biocompatibility of synthetic herniological prostheses «Progrip», with collagen-stimulating effect of ascorbic acid on the growth of connective tissue in the experiment. We examined characteristics of collagenogenesis in the anterior abdominal wall depending on the effect of vitamin C using the method of polarization microscopy. We suggest a new way to stimulate reparation process by ascorbic acid which would help to optimize forming functionally matured structures of connective tissue of the anterior abdominal wall surrounding endoprosthesis. Due to the results of our investigation it has been clear that modification effect of vitamin C is positive for synthesis of collagen in the periprosthetic capsule for any type of endoprosthesis. It has been proves by statistically reliable increase in ratio of collagen types I and III when vitamin C is used in the diet of experimental animals.

[The structure of the internal carotid artery wall in pathological tortuosity]

OBJECTIVE

to study a change in the content of main components of the internal carotid artery (ICA) wall in pathological tortuosity (PT) resulting from fibromuscular dysplasia, using immunohistochemistry and confocal laser scanning microscopy.

MATERIAL AND METHODS

Immunohistochemical (IHC) analysis using antibodies to elastin, collagen types I and III, and smooth muscle actin was made. The levels of elastin and matrix metalloproteinase 9 (MMP-9) were determined by confocal laser scanning microscopy. The relative area of expression and the area of co-location of these markers were measured.

RESULTS

IHC examination of the expression of elastin revealed that the patients with PT of ICA had its higher content than the controls, but they were observed to have fiber fragmentation. Comparison of collagen types I and III expressions showed no significant differences between the groups. The found significantly lower smooth muscle actin expression in the patients with PT of ICA than in the controls was suggestive of the decreased levels of smooth muscle cells. Confocal microscopy analysis showed high elastin and low MMP-9 expressions in the control group and, on the contrary, low elastin and high proteinase levels in the PT group (р<0.05).

CONCLUSION

One of the causes of PT is impairment in vascular elastic properties due to the destruction of elastic fibers and to their fragmentation, as well as to the decreased count of smooth muscle cells, which in turn causes enhanced MMP-9 activity and tissue matrix degradation.

[Up-regulation of miR-21 promotes cell proliferation and collagen synthesis in pulmonary fibroblasts]

OBJECTIVE

To explore the expression of miR-21 in lung tissues of mice with pulmonary fibrosis, and its role in proliferation, trans-differentiation and collagen synthesis of pulmonary fibroblasts.

METHODS

Thirty C57BL/6 mice were randomly divided into control group (n=5) and model group (n=25). Mice in the latter group were intratracheally administered with bleomycin to establish pulmonary fibrosis model. Five animals in the model group were sacrificed on days 3, 7, 14, 28 and 56, while all ones of the control group were killed on day 56 as total control. The expression of miR-21 in lung tissues was then measured through fluorescence real-time quantitative PCR. Pulmonary fibroblasts were treated with Lipofectamine™2000 (blank control group) as well as miR-21 negative control, mimics and inhibitor, respectively. Cell proliferative ability was analyzed by MTT assay. The mRNA and protein expressions of α-smooth muscle actin (α-SMA), a disintegrin and metalloproteinase with thrombospondin type 1 motif (ADAMTS-1), collagen type I (Col1) and collagen type III (Col3) were detected using fluorescence real-time quantitative PCR and Western blotting, respectively.

RESULTS

The expression levels of miR-21 in lung tissues of the model group on days 7-56 were higher than those in the control group, and reached the peak on day 28. After 24, 48, 72 and 96 hours of co-culture, cell viability significantly increased in miR-21 mimics group but decreased in miR-21 inhibitor group as compared with blank control group. In comparison with blank control group, miR-21 mimics group showed up-regulated mRNA and protein expression levels of α-SMA, Col1 and Col3 while down-regulated ADAMTS-1 mRNA and protein expression levels; however, miR-21 inhibitor group presented with reduced mRNA and protein expression levels of α-SMA, Col1 and Col3 but increased ADAMTS-1 mRNA and protein expression levels. There was no significant difference in the above indicators between negative control group and blank control group.

CONCLUSION

miR-21 expression is raised in lung tissues of mice with pulmonary fibrosis. Up-regulation of miR-21 facilitates the proliferation, trans-differentiation and collagen synthesis of pulmonary fibroblasts.

Adiponectin attenuates lung fibroblasts activation and pulmonary fibrosis induced by paraquat

Pulmonary fibrosis is one of the most common complications of paraquat (PQ) poisoning, which demands for more effective therapies. Accumulating evidence suggests adiponectin (APN) may be a promising therapy against fibrotic diseases. In the current study, we determine whether the exogenous globular APN isoform protects against pulmonary fibrosis in PQ-treated mice and human lung fibroblasts, and dissect the responsible underlying mechanisms. BALB/C mice were divided into control group, PQ group, PQ + low-dose APN group, and PQ + high-dose APN group. Mice were sacrificed 3, 7, 14, and 21 days after PQ treatment. We compared pulmonary histopathological changes among different groups on the basis of fibrosis scores, TGF-β₁, CTGF and α-SMA pulmonary content via Western blot and real-time quantitative fluorescence-PCR (RT-PCR). Blood levels of MMP-9 and TIMP-1 were determined by ELISA. Human lung fibroblasts WI-38 were divided into control group, PQ group, APN group, and APN receptor (AdipoR) 1 small-interfering RNA (siRNA) group. Fibroblasts were collected 24, 48, and 72 hours after PQ exposure for assay. Cell viability and apoptosis were determined via Kit-8 (CCK-8) and fluorescein Annexin V-FITC/PI double labeling. The protein and mRNA expression level of collagen type III, AdipoR1, and AdipoR2 were measured by Western blot and RT-PCR. APN treatment significantly decreased the lung fibrosis scores, protein and mRNA expression of pulmonary TGF-β₁, CTGF and α-SMA content, and blood MMP-9 and TIMP-1 in a dose-dependent manner (p<0.05). Pretreatment with APN significantly attenuated the reduced cell viability and up-regulated collagen type III expression induced by PQ in lung fibroblasts, (p<0.05). APN pretreatment up-regulated AdipoR1, but not AdipoR2, expression in WI-38 fibroblasts. AdipoR1 siRNA abrogated APN-mediated protective effects in PQ-exposed fibroblasts. Taken together, our data suggests APN protects against PQ-induced pulmonary fibrosis in a dose-dependent manner, via suppression of lung fibroblast activation. Functional AdipoR1 are expressed by human WI-38 lung fibroblasts, suggesting potential future clinical applicability of APN against pulmonary fibrosis.

Ca2+-calcineurin signaling is involved in norepinephrine-induced cardiac fibroblasts activation

Cardiac fibroblasts (CFs) activation plays a vital role in cardiac fibrosis. There are some studies demonstrate that norepinephrine (NE, an α1-adrenoceptor agonist) induced CFs proliferation. But whether Ca2+-calcineurin, a signaling concerned with growth and differentiation in various cell types, is participated in NE-induced CFs activation is unclear. In present study, we determined NE-induced CFs proliferation and differentiation, synthesis of collagen, and calcineurin (CaN) activity, and the effects of phentolamine (Phen, an α1-adrenoceptor antagonist), verapamil (Ver, a calcium channel blocker) and cyclosporine A (CsA, an inhibitor of CaN) on NE-induced CFs activation. The results showed that NE induced CFs proliferation and differentiation, increased α-SMA protein expression, increased collagen I, collagen III and fibronectin production, promoted ECM expression, activated CaN and increased CaN protein expression, which were inhibited by Phen, Ver and CsA. In vivo, more collagen deposition could be observed and total collagen volume fraction (CVF) was significantly increased in NE group. Phen, Ver and CsA decreased NE-induced collagen deposition, reduced cardiac fibrosis. Thus, our results demonstrate that Ca2+/CaN is involved in NE-induced CFs proliferation and collagen synthesis.

Protein O glycosylation regulates activation of hepatic stellate cells

It was reported that O glycosylation is associated with hepatic stellate cell activation and regulates collagen expression. In this study, we aimed to investigate the effect of O glycosylation on the activation of human hepatic stellate cells. We found that the inhibitor of O glycosylation, benzyl-α-GalNAc (2 and 4 mM), could significantly inhibit cells proliferation in a dose-dependent manner. Moreover, benzyl-α-GalNAc decreased the expressions of α-smooth muscle actin, collagen I, and collagen III. The results indicate that O glycosylation is involved in the activation of hepatic stellate cells.

Extraperitoneal and intraperitoneal behavior of several biological meshes currently used to repair abdominal wall defects

BACKGROUND

This study compares the behavior of several cross- and noncrosslinked biomeshes (Permacol®, CollaMend®, Surgisis®, Tutomesh®, and Strattice®) currently used for abdominal wall repair when implanted intraperitoneally and extraperitoneally. Material and Methods. Intraperitoneal (IP) implants were fixed on the parietal peritoneum and partial abdominal wall defects (EP) were repaired using each of the biomeshes, in the rabbit abdominal wall. After 90 days of implant, the biomeshes were examined to assess biomesh degradation, collagen I and III expression (Sirius red staining) and the host macrophage response (immunohistochemistry). Results. Following implant, the thinner noncrosslinked biomeshes Tutomesh and Surgisis, were almost fully degraded in both models. In contrast, Strattice behavior was similar to crosslinked biomeshes, showing negligible degree of degradation. This mesh also showed high expression of collagen I, similar to the crosslinked. The noncrosslinked materials elicited lower macrophage counts, significantly so for Strattice. In IP and EP models, Permacol showed similarly high macrophages while counts were lower for CollaMend and Surgisis in the EP model. Conclusions. The intra or extraperitoneal implant of the different meshes did not affect host tissue incorporation or mesh degradation. The crosslinked biomeshes induced a more intense macrophage response regardless of their IP or EP location.

GLP-1R agonist may activate pancreatic stellate cells to induce rat pancreatic tissue lesion

OBJECTIVE

To explore the mechanism of GLP-1R agonist-induced rat pancreatic tissue lesion.

METHODS

Thirty SD male rats were divided into three groups, namely GLP-1R agonist experimental group, diabetes-model experimental group and control group. Diabetes-model rats were induced by streptozotocin and high-sugar high-fat diet. GLP-1R agonist group and diabetes-model group were administered with GLP-1R agonist in dose 5 μg/kg each time, twice a day. After 10 weeks of treatment, the amount of matrix metalloproteinase (MMP)-2 and MMP-9, and expression of α-smooth muscle actin (α-SMA) and type III collagen protein in pancreatic tissue were measured.

RESULTS

The amount of MMP-2 and MMP-9 in GLP-1R agonist group and diabetes-model group were significantly higher than the control group. Compared with the GLP-1R agonist group, the diabetic model group had more severe pathological changes of pancreatic tissue interstitial edema, inflammatory cell infiltration, glandular atrophy and fibrosis, and significantly increased pancreatic tissue MMP-2 and MMP-9 levels, significantly increased α-SMA and collagen III-positive cell counts, all the differences were statistically significant. α-SMA and type III collagen were expressed in all parts of the lesions of GLP-1R agonist group and diabetes-model group. α-SMA can only be observed in the vessel wall in control group, however, in the other two groups, α-SMA can also be observed in pancreatic acinar cell interstitia, in addition to vessel wall.

CONCLUSIONS

Long-term subcutaneous GLP-1R agonist injection may activate pancreatic stellate cells, causing the expression of α-SMA and collagen III and the amount of MMP-2 and MMP-9 in pancreatic acinar cell interstitial significantly increasing, and thus inducing chronic inflammatory change.

Activin A is stimulated by tumor necrosis factor-alpha and modulates collagen gene expression in human amniotic cells

BACKGROUND

Accumulating evidence supports the idea of activin A as a modulator of inflammation. In human pregnancy, elevated activin A concentrations in amniotic fluid are reported in women with intra-amniotic infection and inflammation- induced pre-term birth.

AIM

To test the hypothesis that activin A was involved in the pathophysiology of amnionitis, we evaluated the effects of tumor necrosis factor-α and lipopolysaccharide on activin A production in human amniotic epithelial cells, and the effects of activin A on the expression of collagen mRNA in amniotic mesenchymal cells.

MATERIALS AND METHODS

Amniotic membranes were obtained from patients without systemic disease, signs of premature delivery or fetal complications, during elective cesarean sections at term. Amniotic epithelial cells and mesenchymal cells were separately obtained by enzymatic digestion and cultured. Activin A was measured by enzyme-linked immunosorbent assay and collagen mRNA levels were assessed by quantitative PCR.

RESULTS

Amniotic epithelial cells produced activin A in a cell density- and time-dependent manner. Tumor necrosis factor- α enhanced activin A production in a time-dependent (48-120 h) and dose-dependent (10-300 ng/ml) manner in amniotic epithelial cells. Lipopolysaccharide also stimulated activin A production, but the effect was less prominent. In amniotic mesenchymal cells, the effect of activin A on the expression of type I and type III collagen mRNA was suppressive.

CONCLUSIONS

Tumor necrosis factor-α and lipopolysaccharide stimulated activin A production in amniotic epithelial cells, and activin A modulated expression of collagen mRNA in amniotic mesenchymal cells. These results support the idea that activin A is involved in the pathophysiology of amnionitis.

[Conivaptan inhibites cell proliferation and collagen production of cardiac fibroblasts induced by arginine vasopressin]

OBJECTIVE

To investigate the effects of arginine vasopressin (AVP) and its receptor antagonist conivaptan (CON) on the proliferation of cardiac fibroblasts (CFs) and the production of collagen I and III.

METHODS

CFs were isolated by collagenase II method and purified with differential attachment and detachment methods. The cell viability of CFs after AVP and/or CON administration was assessed by cell counting kit-8 (CCK-8). The expressions of COL1A1 and COL3A1 mRNA were detected by RT-PCR, and the protein levels of (collagen type 1, alpha 1, COL1A1) and COL3A1 were assessed by Western blotting.

RESULTS

At 24 h after intervention, 10(-7); mol/L AVP promoted the proliferation of CFs in comparison with that in control group (P<0.01), and 10(-7); mol/L CON inhibited the effect significantly (P<0.01). At 12 h after intervention, 10(-7); mol/L AVP significantly enhanced the expressions of COL1A1 and COL3A1 at both mRNA and protein levels, and 10(-7); mol/L CON inhibited the effect again.

CONCLUSION

AVP promoted the proliferation of CFs and enhanced the COL1A1 and COL3A1 expressions at both mRNA and protein levels, while CON could restrain the AVP effects partially.

Comparison of the effects between animal-derived trypsin and recombinant trypsin on human skin cells proliferation, gene and protein expression

Animal-derivative free reagents are preferred in skin cell culture for clinical applications. The aim of this study was to compare the performance and effects between animal-derived trypsin and recombinant trypsin for skin cells culture and expansion. Full thickness human skin was digested in 0.6 % collagenase for 6 h to liberate the fibroblasts, followed by treatment with either animal-derived trypsin; Trypsin EDTA (TE) or recombinant trypsin; TrypLE Select (TS) to liberate the keratinocytes. Both keratinocytes and fibroblasts were then culture-expanded until passage 2. Trypsinization for both cell types during culture-expansion was performed using either TE or TS. Total cells yield was determined using a haemocytometer. Expression of collagen type I, collagen type III (Col-III), cytokeratin 10, and cytokeratin 14 genes were quantified via RT-PCR and further confirmed with immunocytochemical staining. The results of our study showed that the total cell yield for both keratinocytes and fibroblasts treated with TE or TS were comparable. RT-PCR showed that expression of skin-specific genes except Col-III was higher in the TS treated group compared to that in the TE group. Expression of proteins specific to the two cell types were confirmed by immunocytochemical staining in both TE and TS groups. In conclusion, the performance of the recombinant trypsin is comparable with the well-established animal-derived trypsin for human skin cell culture expansion in terms of cell yield and expression of specific cellular markers.

[Effects of Ac-SDKP on angiotensin II-induced collagen synthesis in vascular adventitial fibroblasts]

OBJECTIVE

To investigate the effect of an anti-fibrotic tetra peptide Ac-SDKP on vascular fibrosis by regulating extracellular regulated protein kinase (ERK1/2) activity through Ang II.

METHODS

Rat vascular adventitial fibroblasts were cultured in vitro. They were randomly divided into control group, Ang II (10(-6) mmol/L) group, Ang II and Ac-SDKP joint action group, PD98059 group. Type I, III collagen contents in adventitia fibroblasts were measured by RT-PCR and the expressions of matrix metalloproteinases (MMP-2) and transforming growth factor-beta1 (TGF-beta1) were determined by Western blot.

RESULTS

Ac-SDKP could reduced Ang II-induced expression of type I, III collagen secretion and TGF-beta1 at mRNA,and increase MMP-2 expression, PD98059 could inhibit the above effect.

CONCLUSION

The results suggested that Ac-SDKP could inhibit the formation and development of vascular fibrosis through blocking ERK1/2 pathway mediated by Ang II. Ac-SDKP therefore served as an antifibrotic factor in vascular fibrosis.

Serum markers of deranged myocardial collagen turnover: their relation to malignant ventricular arrhythmias in cardioverter-defibrillator recipients with heart failure

BACKGROUND

Pathologic collagen remodeling has been involved in the occurrence of ventricular arrhythmias and sudden cardiac death in heart failure. The aim of the study was to investigate the relationship between malignant ventricular arrhythmias and cardiac collagen turnover indexes, expressing specific types of derangement in collagen physiology, in stable patients with an implantable cardioverter-defibrillator (ICD).

METHODS

Seventy-four patients with an ICD and heart failure were studied. They had coronary artery disease (n = 42) or dilated cardiomyopathy, New York Heart Association classes I and II, and left ventricular ejection fraction 29% ± 1%. An ICD had been implanted for secondary (n = 36) or primary prevention of sudden cardiac death. We assessed (1) markers of collagen types I and III synthesis and their ratio: procollagen type I carboxyterminal peptide (PICP), procollagen type III aminoterminal peptide (PIIINP), and PICP/PIIINP; (2) markers of collagen degradation, degradation inhibition, and their ratio: matrix metalloproteinase 9 (MMP-9), tissue inhibitor of matrix metalloproteinase (TIMP) 1 (TIMP-1), and MMP-9/TIMP-1. Patients were prospectively followed up for 1 year. The number of episodes necessitating appropriate interventions for ventricular tachyarrhythmias (>170 beat/min) was related to the assessed parameters.

RESULTS

Multivariate analysis revealed a significant relation between the number of tachyarrhythmic episodes and MMP-9/TIMP-1 (P = .007), PICP/PIIINP (P = .007), and ejection fraction (P = .04). No other significant relation was observed between arrhythmias and the remaining parameters.

CONCLUSION

In heart failure, biochemical markers indicative of a deranged equilirium in myocardial collagen deposition/degradation and collagen I/III synthesis are related to ventricular arrhythmogenesis. Further studies are needed to investigate their predictive ability.

In vitro changes in human tenocyte cultures obtained from proximal biceps tendon: multiple passages result in changes in routine cell markers

PURPOSE

Results of in vitro cell models are commonly used to promote new therapies (e.g., platelet-rich plasma), and clinicians have to be aware of the specific limitations of such models. To gain a sufficient and effective cell load, many current in vitro models use cells multiplied through various passages. This is especially important in tendon-like cell (TLC) models, since native tendon tissue is not available unlimited and contains limited amount of tenocytes. The purpose was to determine the occurrence of phenotypic changes following extended monolayer culture of TLCs, according to cell-passage number.

METHODS

Tendon samples were obtained from 15 healthy patients undergoing biceps tenodesis. Tendons were digested and cultured (monolayer) for six passages. Tendon-specific markers (collagens I and III, decorin, tenascin-C, and tenomodulin) and their histology were analyzed using gene expression and protein content assays. Native cells, the cells cultured and cells passaged one to six times were analyzed at each passage.

RESULTS

Gene expression of types I and III collagen of cultured TLCs significantly decreased after two passages. Gene expression of decorin, tenascin-C, and tenomodulin exhibited a trend of decreased gene expression with increased passage. Protein levels of types I and III collagen and decorin decreased after four passages.

CONCLUSIONS

The significant findings let conclude that tenocyte-like cells obtained from human LHB can be maintained in monolayer culture at low passages, before the signs of phenotypic drift are present. But researchers must be aware of rapid phenotypic drift at higher passage numbers. Therefore, only cells within the first 3 passages should be used as a precaution for in vitro monolayer cell models, and one has to be aware of the phenotypic changes if TLCs passaged multiple times are used. The clinical relevance of this data is that understanding of in vitro TLC models, and their limitations may finally help the clinician to judge the potential of experimental data of new biologic treatment options.

[Release of HMGB1 by LPS-treated cardiac fibroblasts and its contribution to the production of collagen type I and III]

AIM

To investigate whether cardiac fibroblasts (CFs) treated by LPS can actively secrete high-mobility group box protein 1 (HMGB1) and to analyze the correlation between HMGB1 releasing and the accumulation of collagen type I , III .

METHODS

CFs were isolated from the heart of 7-14-day-old BALB/c mice and cultured in DMEM with 10% fetal bovine serum (FBS). We collected the CFs and cell supernatants after treated by LPS for 0, 6, 12, 24, 36, 48 h, respectively. The mRNA and protein expression levels of HMGB1, collagen 1a1 (col1a1) and collagen 3a1 (col3a1) in CFs after LPS stimulation were detected by RT-PCR and Western blotting, respectively. The intracellular localization of HMGB1 in treated CFs was investigated by immunofluorescence.

RESULTS

After 0-6 h of LPS stimulation, the mRNA levels of HMGB1, col1a1, col3a1 had no significant changes; but increased obviously at 12, 24, 36, 48 h. HMGB1 was found in the cell supernatant by Western blotting after 24 h LPS stimulation, and its expression decreased following the first rise in CFs. Meanwhile, immunofluorescence showed HMGB1 translocation from nucleus to cytoplasm. The levels of col1a1 and col3a1 were up-regulated in CFs after stimulation.

CONCLUSION

LPS can induce HMGB1 translocation from nucleus to cytoplasm and across cellular membrane to the outside of CFs at a time-dependent manner. Col1a1 and Col3a1, which are closely associated with myocardial fibrosis, were obviously up-regulated by LPS stimulation, which indicates that actively released HMGB1 might contribute to myocardial fibrosis following the endotoxin induced-sepsis.

[Correlation of the expression of NF-κB p65 and hepatic fibrosis in hepatitis patients]

OBJECTIVE

To explore the relationship between the expression of NF-κB p65 and hepatic fibrosis in chronic hepatitis B (CHB) patients.

METHODS

Sixty CHB patients with hepatic fibrosis underwent liver biopsy to determine the stages of liver fibrosis (S0-S4). The distribution and expression of collagens I, III and NF-κB p65 in different stages of fibrosis in liver tissue were observed by immunohistochemistry and the results analyzed statistically.

RESULTS

The expression of NF-κB p65 was positively correlated with the stage of hepatic fibrosis. That was S4 > S3 > S2 > S1 (S0) (P < 0.01). And it was also positively correlated with the expression of collagens I and III (P < 0.01).

CONCLUSION

The elevated expression of NF-κB p65 is closely associated with the occurrence and development of hepatic fibrosis. Its mechanism is probably related with the increased secretion of collagens I and III after the activation of hepatic stellate cell.

A new antifibrotic target of Ac-SDKP: inhibition of myofibroblast differentiation in rat lung with silicosis

Background

Myofibroblast differentiation, characterized by α-smooth muscle actin (α-SMA) expression, is a key process in organ fibrosis, and is induced by TGF-β. Here we examined whether an anti-fibrotic agent, N-acetyl-seryl-aspartyl-lysylproline (Ac-SDKP), can regulate induction of TGF-β signaling and myofibroblast differentiation as a potential key component of its anti-fibrotic mechanism in vivo and in vitro.

Methodology/Principal Findings

Rat pulmonary fibroblasts were cultured in vitro and divided to 4 groups 1) control; 2) TGF-β1; 3) TGF-β1+ LY364947; 4) TGF-β1+Ac-SDKP. For in vivo studies, six groups of animals were utilized 1) control 4w; 2) silicotic 4w; 3) control 8w; 4) silicotic 8w; 5) Ac-SDKP post-treatment; 6)Ac-SDKP pre-treatment. SiO₂ powders were douched in the trachea of rat to make the silicotic model. Myofibroblast differentiation was measured by examining expression of α-SMA, as well as expression of serum response factor (SRF), a key regulator of myofibroblast differentiation. The expressions of collagen, TGF-β1 and RAS signaling were also assessed. The results revealed that TGF-β1 strongly induced myofibroblast differentiation and collagen synthesis in vitro, and that pre-treatment with Ac-SDKP markedly attenuated myofibroblast activation, as well as induction of TGF-β1 and its receptor. Similar results were observed in vivo in the pathologically relevant rat model of silicosis. Ac-SDKP treatment in vivo strongly attenuated 1) silicosis-induced increased expressions of TGF-β1 and RAS signaling, 2) myofibroblast differentiation as indicated by a robust decrease of SRF and α-SMA-positive myofibroblast localization in siliconic nodules in the lung, 3) collagen deposition.

Conclusion/Significance

The results of the present study suggest a novel mechanism of action for Ac-SDKP’s beneficial effect in silicosis, which involves attenuation of TGF-β1 and its receptors, SRF and Ang II type 1 receptor (AT₁) expression, collagen deposition and myofibroblast differentiation. The results further suggest that therapies targeting myofibroblast differentiation may have therapeutic efficacy in treatment of silicosis of the lung.

Topical application of Acalypha indica accelerates rat cutaneous wound healing by up-regulating the expression of Type I and III collagen

ETHNOPHARMACOLOGICAL RELEVANCE

Acalypha indica Linn. (Acalypha indica) vernacularly called Kuppaimeni in Tamil, has been used as a folklore medicine since ages for the treatment of wounds by tribal people of Tamil Nadu, Southern India. The present study investigates the biochemical and molecular rationale behind the healing potential of Acalypha indica on dermal wounds in rats.

MATERIAL AND METHODS

Acalypha indica extract (40 mg/kg body weight) was applied topically once a day on full-thickness excision wounds created on rats. The wound tissue was removed and used for estimation of various biochemical and biophysical analyses and to observe histopathological changes with and with-out extract treatment. The serum levels of pro-inflammatory cytokine tumor necrosis factor (TNF-α) was measured at 12 h, 24 h, 48 h and 72 h post-wounding using ELISA. Reverse transcription-polymerase chain reaction (RT-PCR) analysis was performed to study the expression pattern of transforming growth factor [TGF-β1], collagen 1 α (I) [Col 1 α (I)] and collagen 3 α (I) [Col 3 α (I)]. Likewise, linear incision wounds were created and treated with the extract and used for tensile strength measurements.

RESULTS

Wound healing in control rats was characterized by less inflammatory cell infiltration, lack of granulation tissue formation, deficit of collagen and significant decrease in biomechanical strength of wounds. Acalypha indica treatment mitigated the oxidative stress and decreased lipid peroxidation with concomitant increase in ascorbic acid levels. It also improved cellular proliferation, increased TNF-α levels during early stages of wound healing, up-regulated TGF-β1 and elevated collagen synthesis by markedly increasing the expression of Col 1 α (I) and Col 3 α (I). Increased rates of wound contraction, epithelialization, enhanced shrinkage temperature and high tensile strength were observed in the extract treated rats.

CONCLUSION

Acalypha indica extract was shown to augment the process of dermal wound healing by its ability to increase collagen synthesis through up-regulation of key players in different phases of wound healing and by its antioxidative potential.

[Influence of exogenous embryonic fibroblasts on collagen type I and type III ratio in the tissues of paraprosthetic capsule (experimental work)]

Nowadays, the use of synthetic prosthesis is obligatory method in surgical treatment of large and giant ventral hernias. We have fulfilled comparative investigation of the dynamics of collagen Type I to Type III ratio in paraprosthetic region in mice when using implants, Esphyl - polyethylene, Ecophlon - polytetrafluorethylene, and Uniflex - polyvinylidenfluoride, with a one- and two-time introduction of cultured fibroblasts into paraprosthetic region at different times after implantations and without the introduction. Use of Sirius Red dye staining and polarization microscopy revealed that, in short period (10 days after endoprosthesis implantation), the implication of fibroblasts and the number of implications did not affect the collagen Types ratio. In later stages (30-60 days after endoprosthesis implantation) a significant increase in collagen Type I was observed when using all the materials. The ratio of collagen Type I to Type III was maximal at all stages of the experiment in the case of the implant Uniflex. Double implication of exogenous fibroblasts accelerated the increase in the collagen Type I to Type III ratio to a greater extent.

[Effects of interleukin-17 on murine pulmonary fibroblast proliferation, transformation and collagen synthesis]

OBJECTIVE

To investigate the effects of interleukin-17 (IL-17) on the proliferation, transformation and collagen synthesis of the lung fibroblasts in mice with bleomycin-induced pulmonary fibrosis.

METHODS

In a mouse model of pulmonary fibrosis established by intratracheal administration of 5 mg/kg bleomycin, the dynamic expressions of IL-17/IL-17 receptor (IL-17R) mRNAs were detected by RT-PCR. At 14 days following bleomycin administration, the pulmonary fibroblasts were isolated, cultured and identified. MTT assay was used to assess the proliferation of the pulmonary fibroblasts in response to IL-17 treatment at different concentrations, and RT-PCR and Western blotting were employed to examine the mRNA and protein expressions of α-smooth muscle actin (α-SMA) and types I and III collagen.

RESULTS

IL-17/IL-17R mRNA levels were increased obviously in the pulmonary fibroblasts of rats with pulmonary fibrosis, and the highest expressions occurred at 14 days following bleomycin administration. Exogenous IL-17, at the optimal concentration of 50 ng/ml, significantly promoted the proliferation of the pulmonary fibroblasts in primary culture and obviously increased α-SMA expression and types I and III collagen synthesis in the fibroblasts.

CONCLUSION

IL-17 can promote the proliferation, transformation, and collagen synthesis of the pulmonary fibroblasts from rats with bleomycin-induced pulmonary fibrosis.

[Effects of Bushen Huoxue Fang on rat cardiac fibroblast proliferation and collagen production in vitro]

OBJECTIVE

To investigate the effects of Bushen Huoxue Fang on the proliferation of rat cardiac fibroblasts and collagen production in the cells.

METHODS

Rat cardiac fibroblasts were isolated and cultured in DMEM containing 10% (group A) or 20% (group B) or no (group C) serum from rats treated with Bushen Huoxue Fang, with cells cultured in DMEM containing 10% FBS as the control (group D). After 72 h of cell culture, the proliferation of the fibroblasts was detected using CCK-8 kit, and collagen mRNA and protein expressions were examined using RT-PCR and Western blotting, respectively.

RESULTS

Compared with that in groups C and D, the cell proliferation decreased significantly in groups A and B, and especially in the latter (P<0.05). RT-PCR demonstrated significant reductions of the mRNAs of type 1 and 3 collagens in groups A and B (P<0.05), and their protein levels were also significantly lowered (P<0.05).

CONCLUSION

Bushen Huoxue Fang can effectively inhibit the proliferation of rat cardiac fibroblasts and reduced collagen type 1 and 3 productions in the cells in vitro.

Hydrolysable tannins of tropical almond show antifibrotic effects in TGF-β1-induced hepatic stellate cells

BACKGROUND

Persistent activation of hepatic stellate cells (HSC-T6) has been known to cause liver fibrosis. In this study, our objective was to investigate the effects of chebulagic acid and chebulinic acid, two hydrolysable tannins of tropical almond (Terminalia chebula) fruits, on collagen synthesis and signal transduction in transforming growth factor-β1-stimulated HSC-T6 cells. The expression of Smad2, Smad3, Smad4, collagen I(α1)/III, and plasminogen activator inhibitor 1 (PAI-1) mRNAs was determined by reverse-transcription polymerase chain reaction and their protein levels were assessed by western blotting.

RESULTS

Results showed that chebulagic acid and chebulinic acid at 20 µmol L(-1) exhibited cytotoxic and anti-proliferative effects on HSC-T6 cells. They also significantly decreased the expression of Smd2, Smad3 and Smad4, and the synthesis of collagen, procollagen I (α1) and III, as well as suppressing the activation of PAI-1; these events consequently facilitated the resolution of fibrosis.

CONCLUSION

These results indicate that both chebulagic acid and chebulinic acid possess antifibrotic activity, and their mechanism of action could be through the inhibition of the Smad pathway.

[The effect of factor VII activating protease treatment on proliferation and collagen synthesis of cultured human pulmonary fibroblasts]

OBJECTIVE

To examine the influence of factor VII-activating protease (FSAP) treatment on cell proliferation and collagen synthesis in human pulmonary fibroblasts (HPF).

METHODS

Cultured HPF were treated with heparin (10 mg/L), platelet-derived growth factor-BB (PDGF-BB, 20 μg/L), FSAP (12 mg/L), aprotinin (10 mg/L) separately and in different mixture. The proliferation of the HPF was determined by 5-bromodeoxyuridine (BrDU) incorporation. The collagen III mRNA was determined by real-time polymerase chain reaction (PCR), and its protein expression, as well as the phosphorylation of p42 / p44 mitogen activated protein kinase (MAPK) were both determined using Western blotting.

RESULTS

PDGF BB significantly (all P < 0.05) induced cell proliferation (1.23 ± 0.06 vs. 1.01 ± 0.01 without heparin, 1.24 ± 0.04 vs. 0.98 ± 0.01 with heparin), collagen III mRNA transcription (1.79 ± 0.02 vs. 1.00 ± 0.00 without aprotinin, 1.57 ± 0.01 vs. 1.00 ± 0.00 with aprotinin), and collagen III protein expression (0.54 ± 0.26 vs. 0.17 ± 0.05 without aprotinin, 0.59 ± 0.31 vs. 0.24 ± 0.15 with aprotinin) in HPF. PDGF BB also significantly (both P < 0.05) induced p42 / p44 MAPK phosphorylation in HPF (0.89 ± 0.24 vs. 0.51 ± 0.17 without aprotinin, 0.97 ± 0.41 vs. 0.37 ± 0.05 with aprotinin). In the presence of heparin FSAP significantly (all P < 0.05) inhibited the PDGF BB induced HPF proliferation (0.92 ± 0.23 vs 1.19 ± 0.11); collagen III mRNA transcription (0.61 ± 0.02 vs. 1.79 ± 0.02) and collagen III protein expression (0.15 ± 0.12 vs. 0.54 ± 0.26). FSAP also inhibited PDGF induced p42 / p44 MAPK phosphorylation in HPF (0.57 ± 0.16 vs. 0.89 ± 0.24) significantly (P < 0.05). The presence of aprotinin lead to a reversal of the inhibitory effect of FSAP on collagen III mRNA transcription (2.37 ± 0.21 vs.0.61 ± 0.02), collagen III protein expression (0.55 ± 0.24 vs. 0.15 ± 0.12) and p42 / p44 MAPK phosphorylation (0.86 ± 0.41 vs. 0.57 ± 0.16, all P < 0.05).

CONCLUSION

FSAP could inhibit the PDGF-BB induced proliferation and collagen III synthesis in HPF in vitro through the suppression of p42 / p44 MAPK phosphorylation.

[Effects on collagen I and III after transplantation of porcine acellular dermal matrix with hyaluronic acid]

OBJECTIVE

To investigate the changes of collagens I and III after the addition of hyaluronic acid in the transplantation of porcine acellular dermal matrix.

METHODS

Full-thickness skin defects were created on the dorsa of Japanese white rabbits. And the rabbits were divided randomly into 3 groups: Group A (hyaluronic acid, porcine acellular dermal matrix plus thin skin autografts), Group B (porcine acellular dermal matrix plus thin skin autografts) and Group C (skin autografts). Skin biopsies were performed at Day 50 post-grafting to detect the contents of collagens I and III by histological examinations, immunohistochemistry method and Western blot.

RESULTS

The areas of skin graft were (13.3 ± 1.2), (9.5 ± 0.9) and (10.0 ± 1.4) cm(2) in Groups A, B and C respectively. Group A was larger than Groups B and C(all P < 0. 01). There was no statistical difference between Groups B and C (P > 0.05). The expressions of collagen I were 1894 ± 164, 515 ± 38 and 395 ± 43 in Groups A, B and C respectively. Group A was higher than Groups B and C (P < 0.01). And the expressions of collagen III were 5411 ± 435, 874 ± 70 and 2078 ± 175 in Groups A, B and C respectively. Group C was higher than Group B and yet lower than Group A (all P < 0.01). The ratios of collagen I and collagen III in Group A (0.39) and Group B (0.59) were higher than that of Group C (0.19) (all P < 0.01).

CONCLUSION

The addition of hyaluronic acid may boost the expression of collagens I and III and decrease the ratio of collagen I/collagen III. Thus it facilitates wound healing and basilar membrane remodeling and alleviates the contraction of skin transplant.

[Inhibitory effect of paeoniflorin on the collagen production by fibroblasts through IL-13/STAT6 signaling pathway]

OBJECTIVE

To observe the effects of paeoniflorin on 3T3 fibroblast activation, proliferation and collagen production through IL-13/STAT6 signaling pathway.

METHODS

3T3 cell strain was cultured with serum-free medium for 12 h, then stimulated by paeoniflorin (200, 400, 600, 800, and 1000 mg/L) or rIL-13 (6.25, 12.5, 50, 100, and 200 microg/L) for another 24 h. At the same time the blank control group for paeoniflorin or rIL-13 was observed. 3T3 cell proliferation was assayed by Cell Counting Kit-8 (CCK-8), and an appropriate concentration (100 microg/L) of rIL-13 was chosen according to the result of cell proliferation. Subsequently, 3T3 cell cultured with serum-free medium for 12 h was stimulated by 100 microg/L rIL-13 for 12 h, and then was treated with different concentrations of paeoniflorin (200, 400, 600, 800, and 1000 mg/L) for another 24 h. Untreated 3T3 cell served as blank control Cell proliferation was measured by CCK-8. Hydroxyproline content in cell supernatant was determined by alkaline lysis method. IL-13Ralpha1, alpha-SMA and STAT6 protein expression were detected by Western blotting. Col-I, Col-III, IL-13Ralpha1 and STAT6 mRNA expression were analyzed by RT-PCR.

RESULTS

Paeoniflorin inhibited 3T3 cell proliferation in a concentration-dependent manner (r = -0.980, P < 0.01), and there was a statistically significant difference among all groups (F = 198.599, P < 0.01). rIL-13 caused a remarkably concentration-dependent increase in proliferation of 3T3 cells (r = 0.538, P < 0.05). Paeoniflorin (200, 400, 600, 800, and 1000 mg/L) inhibited proliferation of 3T3 cell stimulated by rIL-13 in a concentration-dependent manner (1.780 +/- 0.177, 1.636 +/- 0.073, 0.965 +/- 0.066, 0.623 +/- 0.037, 0337 +/- 0.022, r = -0.971, P < 0.01), and among all groups there existed a significant difference (F = 198.537, P < 0.01). Moreover, paeoniflorin also suppressed secretion of hydroxyproline from 3T3 cell stimulated by rIL-13 in a concentration-dependent manner (3.030 +/- 0.094, 2.976 +/- 0.047, 2.814 +/- 0.047, 2.652 +/- 0.124, 2.408 +/- 0.124, r = -0.916, P < 0.01) with a statistical significance among all groups (F = 13.642, P < 0.01). Further investigations showed that paeoniflorin decreased both protein expression of alpha-SMA, IL-13Ralpha1, and STAT6, and mRNA expression of Col-I, Col-III, IL-13Ralpha1, and STAT6 in 3T3 cell stimulated by rIL-13.

CONCLUSION

Paeoniflorin inhibits activation, proliferation of fibroblasts and production of collagen from fibroblasts through IL-13/STAT6 signaling pathway, which might be one of mechanisms of anti-hepatic fibrosis of paeoniflorin in schistosomiasis japonica.

Use of cis-[18F]fluoro-proline for assessment of exercise-related collagen synthesis in musculoskeletal connective tissue

Protein turnover in collagen rich tissue is influenced by exercise, but can only with difficulty be studied in vivo due to use of invasive procedure. The present study was done to investigate the possibility of applying the PET-tracer, cis-[¹⁸F]fluoro-proline (cis-Fpro), for non-invasive assessment of collagen synthesis in rat musculoskeletal tissues at rest and following short-term (3 days) treadmill running. Musculoskeletal collagen synthesis was studied in rats at rest and 24 h post-exercise. At each session, rats were PET scanned at two time points following injection of cis-FPro: (60 and 240 min p.i). SUV were calculated for Achilles tendon, calf muscle and tibial bone. The PET-derived results were compared to mRNA expression of collagen type I and III. Tibial bone had the highest SUV that increased significantly (p<0.001) from the early (60 min) to the late (240 min) PET scan, while SUV in tendon and muscle decreased (p<0.001). Exercise had no influence on SUV, which was contradicted by an increased gene expression of collagen type I and III in muscle and tendon. The clearly, visible uptake of cis-Fpro in the collagen-rich musculoskeletal tissues is promising for multi-tissue studies in vivo. The tissue-specific differences with the highest basal uptake in bone are in accordance with earlier studies relying on tissue incorporation of isotopic-labelled proline. A possible explanation of the failure to demonstrate enhanced collagen synthesis following exercise, despite augmented collagen type I and III transcription, is that SUV calculations are not sensitive enough to detect minor changes in collagen synthesis. Further studies including kinetic compartment modeling must be performed to establish whether cis-Fpro can be used for non-invasive in-vivo assessment of exercise-induced changes in musculoskeletal collagen synthesis.

Fibrin concentration affects ACL fibroblast proliferation and collagen synthesis

Fibrin is a frequently used biomaterial in surgery and tissue engineering. While it has been shown that fibrin supports cellular proliferation and biosynthesis, there is a scarcity of studies focusing on the effects of fibrin concentration. The objective of this study is to assess the effect of fibrin concentrations around the physiological concentration of 3mg/ml on the behavior of ligament fibroblasts. Fibroblasts were obtained from the anterior cruciate ligaments of four pigs and seeded throughout fibrin gels of either 1, 3, or 6 mg/ml fibrin. The gels were collected at 2, 6, and 10 days for measurement of DNA and collagen content. We found that both DNA and collagen content increased significantly over time in gels made with all concentrations of fibrin. However, the increases were significantly lower in gels made with the higher concentrations of fibrin (3 and 6 mg/ml). Microscopic assessment of FITC-labeled gels showed a decrease in pore size at high fibrin concentrations, which might be a reason for the observed effect on bioactivity. To enhance cell behavior and thus clinical results fibrin applications should build on physiologic or sub-physiologic concentrations, and those with higher concentrations, such as currently available sealants, should be used cautiously.

GH and IGF1 levels are positively associated with musculotendinous collagen expression: experiments in acromegalic and GH deficiency patients

OBJECTIVE

Disproportionate growth of musculoskeletal tissue is a major cause of morbidity in both acromegalic (ACRO) and GH-deficient (GHD) patients. GH/IGF1 is likely to play an important role in the regulation of tendon and muscle collagen. We hypothesized that the local production of collagen is associated with the level of GH/IGF1.

DESIGN AND METHODS

As primary outcomes, collagen mRNA expression and collagen protein fractional synthesis rate (FSR) were determined locally in skeletal muscle and tendon in nine ACRO and nine GHD patients. Moreover, muscle myofibrillar protein synthesis and tendon collagen morphology were determined.

RESULTS AND CONCLUSIONS

Muscle collagen I and III mRNA expression was higher in ACRO patients versus GHD patients (P<0.05), whereas collagen protein FSR did not differ significantly between ACRO and GHD patients in muscle (P=0.21) and tendon (P=0.15). IGF1Ea and IGF1Ec mRNA expression in muscle was higher in ACRO patients versus GHD patients (P<0.01). Muscle IGF1Ea mRNA expression correlated positively with collagen I mRNA expression (P<0.01). Tendon collagen fibrillar area tended to be higher in GHD patients relative to ACRO patients (P=0.07). Thus, we observed a higher expression for collagen and IGF1 mRNA in local musculotendinous tissue in ACRO patients relative to GHD patients. Moreover, there was a tendency towards a higher collagen protein FSR and a smaller collagen fibril diameter in ACRO patients relative to GHD patients. The results indicate a collagen-stimulating role of local IGF1 in human connective tissue and add to the understanding of musculoskeletal pathology in patients with either high or low GH/IGF1 axis activity.

In situ hybridization reveals that type I and III collagens are produced by pericytes in the anterior pituitary gland of rats

Type I and III collagens widely occur in the rat anterior pituitary gland and are the main components of the extracellular matrix (ECM). Although ECM components possibly play an important role in the function of the anterior pituitary gland, little is known about collagen-producing cells. Type I collagen is a heterotrimer of two α1(I) chains (the product of the col1a1 gene) and one α2(I) chain (the product of the col1a2 gene). Type III collagen is a homotrimer of α1(III) chains (the product of the col3a1 gene). We used in situ hybridization with digoxigenin-labeled cRNA probes to examine the expression of col1a1, col1a2, and col3a1 mRNAs in the pituitary gland of adult rats. mRNA expression for these collagen genes was clearly observed, and cells expressing col1a1, col1a2, and col3a1 mRNA were located around capillaries in the gland. We also investigated the possible double-staining of collagen mRNA and pituitary hormones, S-100 protein (a marker of folliculo-stellate cells), or desmin (a marker of pericytes). Col1a1 and col3a1 mRNA were identified in desmin-immunopositive cells. Thus, only pericytes produce type I and III collagens in the rat anterior pituitary gland.

Human tendon cell response to 7 commercially available extracellular matrix materials: an in vitro study

PURPOSE

To evaluate the response of human tenocytes in culture to 7 commercially available extracellular matrix (ECM) patches.

METHODS

Four samples of each ECM were incubated in human tenocyte cultures by use of standard methods. Cell adhesion, cell proliferation, and cellular production of type I and type III collagen, decorin, and scleraxis were measured for each sample according to established experimental methods. Histologic samples were examined to measure the migration of the tenocytes into the ECM.

RESULTS

Tenocytes adhered more to samples of layered submucosal pig intestine than the 6 other ECM materials (P < .002). Tenocytes proliferated more and produced more matrix proteins when cultured on ECM derived from unaltered dermal specimens of human or porcine origin (P < .001). Cells were not seen to have migrated into the matrix of any ECM sample.

CONCLUSIONS

Human tenocytes reacted most favorably to dermal ECM samples that were not chemically cross-linked by the manufacturer. Less favorable responses of the human cells were seen when cultured with equine or synthetic ECM, which showed favorable biologic responses in nonhuman models. Cellular migration into the matrix of the ECM is a complex process and cannot be replicated in this model entirely.

CLINICAL RELEVANCE

The results of this study suggest that dermal ECM may more favorably react with human tendon tissue than ECM of other origins. This may have great relevance as research continues in the field of augmenting surgical soft-tissue repair.

[Collagen type III biosynthesis by cultured pubocervical fascia fibroblasts surrounding mono and multifilament polypropylene mesh after estrogens and tamoxifen treatment]

AIM

Surgical procedures using synthetic implants are currently considered as the most efficient therapy for stress urinary incontinence (SUI) and pelvic organ prolapse (POP). Insertion of the tape or mesh causes enhanced collagen synthesis that largely affects the biomechanical property of the implant. This process is significantly modulated by estrogens and improper wound healing and treatment failure may result in hypoestrogenism. The aim of the study was to assess the rate of collagen type II synthesis by pubocervical fascia fibroblasts cultured with polypropylene meshes in the presence of estrogens and tamoxifen.

MATERIAL AND METHODS

Fibroblasts were obtained from pubo-cervical fascia sampled from a 52-year-old premenopausal woman who underwent surgical treatment for SUI and cultured with monofilament or multifilament polypropylene meshes in the presence of 17B-estradiol, estriol, daidzein or tamoxifen. The cultures were run for 216 hr and the media were replaced every 72hr N-terminal propeptide of type III procollagen (PIIINP) was used as a marker of collagen type III synthesis. Its concentration in the media was measured by radioimmunoassay Pubocervical fascia fibroblast cultured with monofilament or multifilament meshes are capable of collagen type III synthesis. Following treatment with estradiol or tamoxifen, the highest PIIINP concentrations were observed after 72 hr whereas in case of estriol, daidzein or no treatment after 144hr of culture, regardless of the type of mesh used.

RESULTS

Only in cultures containing monofilament mesh and stimulated with estriol the high rate of collagen type III synthesis persisted until the end of the experiment. Paradoxically the highest total production of PIIINP was observed in culture treated with tamoxifen, both for multifilament and monofilament meshes.

CONCLUSION

The rate of collagen type III synthesis by pubocervical fascia fibroblast cultured with polypropylene meshes is subjected to modulation by estrogens and antiestrogens.

Significant type I and type III collagen production from human periodontal ligament fibroblasts in 3D peptide scaffolds without extra growth factors

We here report the development of two peptide scaffolds designed for periodontal ligament fibroblasts. The scaffolds consist of one of the pure self-assembling peptide scaffolds RADA16 through direct coupling to short biologically active motifs. The motifs are 2-unit RGD binding sequence PRG (PRGDSGYRGDS) and laminin cell adhesion motif PDS (PDSGR). RGD and laminin have been previously shown to promote specific biological activities including periodontal ligament fibroblasts adhesion, proliferation and protein production. Compared to the pure RADA16 peptide scaffold, we here show that these designer peptide scaffolds significantly promote human periodontal ligament fibroblasts to proliferate and migrate into the scaffolds (for approximately 300 microm/two weeks). Moreover these peptide scaffolds significantly stimulated periodontal ligament fibroblasts to produce extracellular matrix proteins without using extra additional growth factors. Immunofluorescent images clearly demonstrated that the peptide scaffolds were almost completely covered with type I and type III collagens which were main protein components of periodontal ligament. Our results suggest that these designer self-assembling peptide nanofiber scaffolds may be useful for promoting wound healing and especially periodontal ligament tissue regeneration.

Effects of transforming growth factor-β 1 on the early stages of healing of the Achilles tendon in a rat model

We studied the effects of transforming growth factor-beta 1 (TGF-beta 1) on the genetic expression of procollagen type I and III and its effects on structural properties in the early stages of healing in rat Achilles tendon. The Achilles tendons in 90 rats were transsected and repaired immediately. TGF-beta 1 dissolved in phosphate-buffered saline was injected locally at the repair site using two different doses, and outcomes in both groups were compared to that in the control group given phosphate-buffered saline only. Five animals in each group were killed at one, two, and four weeks postoperatively, and the healing tendon was evaluated. A dose-dependent increase in the expression of procollagen type I and III mRNA was found one week postoperatively. The failure load and stiffness of the healing tendon were increased by TGF-beta 1 at two and four weeks.

Pentoxifylline modifies three-dimensional collagen lattice model contraction and expression of collagen types I and III by human fibroblasts derived from post-burn hypertrophic scars and from normal skin

Fibroblasts are thought to be partially responsible for the persisting contractile forces that result in burn contractures. Using a monolayer cell culture and fibroblast populated collagen lattice (FPCL) three-dimensional model we subjected hypertrophic scar and non-cicatricial fibroblasts to the antifibrogenic agent pentoxifylline (PTF - 1mg/mL) in order to reduce proliferation, collagen types I and III synthesis and model contraction. Fibroblasts were isolated from post-burn hypertrophic scars (HSHF) and non-scarred skin (NHF). Cells were grown in monolayers or incorporated into FPCL's and exposed to PTF. In monolayer, cell number proliferation was reduced (46.35% in HSHF group and 37.73% in NHF group, p<0.0001). PTF selectively inhibited collagen III synthesis in the HSHF group while inhibition was more evident to type I collagen synthesis in the NHF group. PTF also reduced contraction in both (HSHF and NHF) FPCL.

[Effect of frequency of cyclic tensile strain on extracellular matrix of rat vascular smooth muscle cells in vitro]

To investigate the effect of different frequencies of cyclic tensile strain on extracellular matrix (ECM) of vascular smooth muscle cells (VSMCs) and to research the relationship between tensile strain and vascular remodeling, the aortic vascular smooth muscle cells of rats grown on dishes coated with collagen I were subjected to 10% elongation and various frequencies of mechanical strain using the Flexercell 4000 Strain Unit. The expression of extracellular matrix including fibronectin, collagen I and collagen III was detected by Real-time RT-PCR, and p38 activity by western blot. The result showed that the expression of extracellular matrix was induced by mechanical strain in a nonlinear frequency-dependent manner, which was mediated by p38 pathway. These results demonstrate that the variety of frequencies of cyclic tensile strain could modulate the expression of ECM. It may have important influence on vascular remodeling.

[Effects of exogenous connective tissue growth factor on collagen III synthesis of human renal tubular epithelial cells]

OBJECTIVE

To explore the role of exogenous connective tissue growth factor (CTGF) in the collagen III synthesis of human renal tubular epithelial cell line HK2 in vitro.

METHODS

Cultured HK2 cells were randomly assigned to three groups: placebo-control, low-dose CTGF-treated (2.5 ng/mL) and high-dose CTGF-treated groups (20 ng/mL). Cell morphological changes were observed under an inverted microscope. Collagen III alpha mRNA expression was detected using RT-PCR. Immunohistochemistry staining was used to assess the levels of intracellular collagen III alpha protein.

RESULTS

After 48 hrs of low- or high- dose CTGF treatment, the appearances of HK2 cells were changed from oval to fusiform. High-dose CTGF treatment increased collagen III alpha mRNA expression (0.4461+/-0.0274 vs 0.2999+/-0.0115; P<0.05) as well as the protein expression of collagen III alpha (0.4075+/-0.0071 vs 0.3503+/-0.0136; P<0.05) compared with the placebo-control group.

CONCLUSIONS

CTGF can induce morphological changes of human renal tubular epithelial cells in vitro. High concentration of CTGF may increase the synthesis of collagen III alpha.

[Effect of pegylated interferon beta-1a therapy on the liver fibrosis in chronic hepatitis C: a semi-quantitative analysis]

OBJECTIVE

To access the effect of pegylated interferon (PEGIFN) beta-1a on the reduction of liver fibrosis in chronic hepatitis C (HVC).

METHODS

Twenty-one patients with chronic HVC were divided into two groups randomly and treated with recombinant human PEGIHN-beta-1a (n = 13) or PEGIHN-beta-1a plus ribavirin (RBV) (n = 8) for 24 weeks, and then followed up for another 24 weeks. The clinical manifestations were observed and the clinical effects were evaluated. Biopsy was conducted before and after the treatment to analyze the histological activity index (HAI) and staging of fibrosis according the modified Knodell scoring system. Immunohistochemical analysis was used to examine the levels of alpha-smooth muscle actin (alpha-SMA), marker of activation of hepatic stellate cells (HSCs), and collagen type III in the HSCs.

RESULTS

Sustained viral response (SVR) was achieved in 7 patients, and end-of-treatment virologic response (ETVR) was achieved in 9 patients. The HAI after treatment was 4.3 +/- 2.2, significantly lower than that before treatment (6.6 +/- 2.2, t = 4.77, P < 0.01). The fibrosis score after treatment was 1.1 +/- 1.1, significantly lower than that before treatment (1.7 +/- 1.2, t = 1.92, P < 0.05). The alpha-SMA score after treatment was 14 +/- 8, significantly lower than that before treatment (20 +/- 11, t = 2.15, P < 0.05). The integrated light density of collagen type III after treatment was 10 +/- 10, significantly lower than that before treatment (16 +/- 12, t = 1.83, P < 0.05). The improvement levels of fibrosis, alpha-SMA score, and integrated light density of collagen type III of the patients with SVR were all better than those of the patients without SVR; however, the differences were all not significant. The patients with combination therapy, female patients, and the patients with the HCV RNA < 2 x 10(6) copies/ml before treatment all showed higher levels in histology response. HAI, alpha-SMA level, and collagen type III values were all significantly correlated with the values of the semiquantitative indexes of fibrosis (all P < 0.01).

CONCLUSION

Resisting hepatitis virus C and inhibiting and reversing the fibrotic progress, IFN-beta-1a therapy improves the liver histology of chronic HVC regardless of the viral response.

[The effect of cigarette smoke on the expression of transforming growth factor-beta1 mRNA and collagen type III in airways of asthmatic rats]

OBJECTIVE

To study the effect of cigarette smoke on the expression of transforming growth factor-beta l (TGF-beta1), and collagen type III in lung tissues, and therefore to investigate the mechanism of airway remodeling.

METHODS

Thirty male Wistar rats were randomly divided into a control group, an asthmatic group and a cigarette smoke treated group, with 10 rats in each group. The expression level of TGF-beta1 mRNA was measured by reverse transcription polymerase chain reaction (RT-PCR) and collagen type III by immunohistochemistry. The thickness of airway wall in each group was also measured. Software SPSS 11.0 was used for statistical analysis (data expressed as +/- s). Group comparison was made by one way ANOVA and Pearson correlation was used for correlation analysis.

RESULTS

The levels of TGF-beta1 mRNA and collagen type III in cigarette smoke treated group (0.42 +/- 0.04, 25.8 +/- 2.3) were higher than those in the asthmatic group (0.39 +/- 0.04, 22.9 +/- 3.1) and in the control group (0.26 +/- 0.04, 16.3 +/- 2.3). Compared to the control group, the levels were higher in the asthmatic group (F = 55.97, 35.61, all P < 0.05). The level of TGF-beta1 mRNA was positively correlated with the expression of collagen type III (r = 0.71, P < 0.05). The thickness of airway wall in the cigarette smoke treated group (23.3 +/- 2.4) microm2/microm was significantly higher than that in the asthmatic group (20.1 +/- 2.9) microm2/microm and the control group (11.6 +/- 2.4) microm2/microm;compared to the control group, it was higher in the asthmatic group (F = 53.68, P < 0.05).

CONCLUSION

Cigarette smoke can promote over-expression of TGF-beta1-mRNA in asthmatic rat airways, increase the expression of collagen type III and aggravate airway remodeling.

[Inhibition of COL1A1 and COL3A1 expression by RNA interference in human skin fibroblasts]

OBJECTIVE

To suppress COL1A1 and COL3A1 gene expressions in human skin fibroblasts (HSFs) by means of RNA interference (RNAi).

METHODS

Three small interfering RNA (siRNA) expression cassette (SEC) sequences were designed for each of the COL1A1 and COL3A1 gene sequences available in GenBank. The synthesized SECs capable of effective gene suppression were transfected into cultured HSFs, either after cloning into the expression vector or mediated by Lipofectamine 2000, and the suppression of the target genes at both mRNA and protein levels was determined by quantitative fluorescence RT-PCR and Western blotting, respectively.

RESULTS

Transfection of the SECs into HSFs resulted in specific depression of COL1A1 and COL3A1 expressions (down to 5.00% and 6.48%, respectively). The expression vector-mediated RNAi established a HSF cell line with persistent gene knockdown for over 30 days (to 25.21% and 22.12%, respectively).

CONCLUSION

COL1A1 and COL3A1 gene expressions can be specifically and efficiently inhibited in HSFs by either liposome- or vector-mediated SEC transfection.

Enhanced alpha 1(I) mRNA expression in frozen shoulder and dupuytren tissue

The purpose of this study has been to investigate collagen I and III synthesis during the fibrosing stage of frozen shoulder and Dupuytren samples in comparison to normal capsule tissue. - By using the quantitative PCR significantly increased levels of alpha 1(I) mRNA transcription in samples of frozen shoulder (p = 0.016) and Duypuytren (p = 0.041) could be demonstrated, whereas alpha 2(I) and alpha 1(III) chains have shown the same mRNA levels as in normal capsule tissue. - Despite an enhancement of alpha 1(I) mRNA transcription in frozen shoulder and Dupuytren samples the intracellular precursor procollagen I and extracellular mature collagen I was detected immunohistochemically in reduced levels. - The structural alteration of collagen I assembly might be caused by disturbed post-translation from the polypeptide chains into the triple helices procollagen I though alpha 1(I) mRNA transcription was significantly increased and alpha 2(I) mRNA transcription was in normal range. Fibroblasts might release high quantities of free alpha 1(I) polypeptide chains or (alpha 1(I)) 3 homotrimer into the extracellular space during the fibrosing stage of frozen shoulder and Dupuytren disease. - In all samples neither differences of alpha 1(III) mRNA transcription nor differences of immunohistochemical staining intensity of collagen III could be seen. This might result from apoptosis of myofibroblasts in the final phase of the fibrosing processes. - The stimulating effect of insulin-like growth factor type I (IGF-I) to induce fibrosis in connective tissue such as scarlet is known. In all patients suffering from frozen shoulder and Dupuytren disease the serum IGF-I level was in a normal range and the IGF-I receptor - (IGFR-I) mRNA transcription in the samples was also in the same level compared with normal capsule tissue.

Collagen stiffness regulates cellular contraction and matrix remodeling gene expression

Cell-level mechanical and 3D spatial cues are essential to the organization and architecture of new tissues that form during growth, repair or in bioreactors. Fibroblast-seeded 3D collagen constructs have been used as bioartifical extracellular matrix (ECM) providing a 3D environment to embedded resident cells. As cells attach to scaffold fibrils, they generate quantifiable contractile forces which depend on cell type, cell attachment, cell density, growth factors, and matrix stiffness. The aim of this study was to quantify the cytomechanical and molecular responses of human dermal (HDF) and neonatal foreskin fibroblasts (HNFF) seeded in constructs of increased stiffness. We also tested the effect of blocking early attachment using serum starvation on these outputs. Constructs were placed under uniaxial strains of 0-10% to increase scaffold stiffness, prior to gel contraction, and force generation was monitored using a tensional culture force monitor (t-CFM). Increased matrix stiffness reduced generation of quantifiable cellular force (up to 70%) over 24 h in both cell types and delayed the onset of measurable contraction (upto sevenfold). The delay of measurable force generation was cell lineage dependent but not FCS dependent. Gene expression of MMP-2, TIMP-2, and collagen type III expression in HDFs were significantly upregulated in constructs of increased stiffness. HNFFs did not show any significant changes in these gene expressions indicating a lineage specific response.

Inhibition of Smad3 expression decreases collagen synthesis in keloid disease fibroblasts

BACKGROUND

Keloids represent a dysregulated response to cutaneous wounding that result in an excessive deposition of extracellular matrix (ECM), especially types I and III collagen. In keloid scars, the ratio of 'type I to type III collagen' varies compared to normal skin. Transforming growth factor beta (TGF-beta) plays a central role in the pathogenesis of fibrosis by inducing and sustaining activation of keloid fibroblasts. However, the underlying mechanisms are poorly understood. RNA interference (RNAi) is an evolutionally conserved mechanism for repressing targeted gene expression. In mammalian cells, RNAi is mediated by small interfering RNA (siRNA). In this paper, we examined the function of Sma and Drosophila mothers against decapentaplegic homolog 3 (Smad3), recently characterized as intracellular effector of TGF-beta signalling, in keloid fibroblasts using siRNA.

METHODS

Dermal fibroblasts obtained from one female patient aged 21 years were maintained in Dulbecco's modified Eagle's medium. Cells (<6 passages) were treated with or without Smad3 siRNA and the expression levels of related genes were examined by Reverse Transcription Polymerase Chain Reaction (RT-PCR) and Western Blot. Statistical analysis was performed using one-way ANOVA (Dunnett correction) and the Excel 7.0 software, with significance set at p<0.05.

RESULTS

The knockdown of Smad3 expression in mRNA and protein levels was confirmed using RT-PCR and Western Blot. Compared to blank, the mRNA levels of types I and III procollagen were also significantly and uniquely decreased following the reduction of Smad3 by siRNA (p<0.05). The results indicate that Smad3 plays an important role in the TGF-beta induced fibrosis in keloid. Downregulation of Smad3 expression in keloid fibroblasts can significantly decrease procollagen gene expression. SiRNA targeting Smad3 was an efficient reagent to reduce ECM deposition and attenuate process of fibrosis. It could be a new promising therapeutic approach to improve skin wound healing and inhibit progression of fibrotic conditions by interrupting the TGF-beta signal pathway.

Cyclical mechanical stretch modulates expression of collagen I and collagen III by PKC and tyrosine kinase in cardiac fibroblasts

Mechanical load and chemical factors as stimuli for the different pattern of the extracellular matrix (ECM) could be responsible for cardiac dysfunction. Since fibroblasts can both synthesize and degrade ECM, ventricular fibroblasts from adult rat hearts underwent cyclical mechanical stretch (CMS; 0.33 Hz) by three different elongations (3%, 6%, 9%) and four different serum concentrations (0%, 0.5%, 5%, 10%) within 24 h. Expression of collagen I and III, as well as matrix metalloproteinase-2 (MMP-2), tissue inhibitor of MMP-2 (TIMP-2), and colligin were analyzed by RNase protection assay. In the absence of serum, 9% CMS increased the mRNA of collagen I by 1.70-fold and collagen III by 1.64-fold. This increase was prevented by the inhibition either of PKC or of tyrosine kinase but not of PKA. Inhibition of PKC or tyrosine kinase itself reduced the expression of collagen I and collagen III mRNA. The mRNA of MMP-2, TIMP-2, and colligin showed the same tendency by stretch. Combined with 10% serum, 6% CMS reduced the mRNA of collagen I (0.62-fold) and collagen III (0.79-fold). Inhibition of PKC or tyrosine kinase, but not of PKA, prevented the reduction of collagen I and collagen III mRNA in 10% serum. The results show that the response of fibroblasts to CMS depends on the serum concentration. At least two signaling pathways are involved in the stretch-induced ECM regulation. Myocardial fibrosis due to ECM remodeling contributes to the dysfunction of the failing heart, which might be attributed to changes in hemodynamic loading.