Changes in histoanatomical distribution of types I, III and V collagen promote adaptative remodeling in posterior tibial tendon rupture

INTRODUCTION: Posterior tibial tendon dysfunction is a common cause of adult flat foot deformity, and its etiology is unknown. PURPOSE: In this study, we characterized the morphologic pattern and distribution of types I, III and V collagen in posterior tibial tendon dysfunction. METHOD: Tendon samples from patients with and without posterior tibial tendon dysfunction were stained by immunofluorescence using antibodies against types I, III and V collagen. RESULTS: Control samples showed that type V deposited near the vessels only, while surgically obtained specimens displayed type V collagen surrounding other types of collagen fibers in thicker adventitial layers. Type III collagen levels were also increased in pathological specimens. On the other hand, amounts of collagen type I, which represents 95% of the total collagen amount in normal tendon, were decreased in pathological specimens. CONCLUSION: Fibrillogenesis in posterior tibial tendon dysfunction is altered due to higher expression of types III and V collagen and a decreased amount of collagen type I, which renders the originating fibrils structurally less resistant to mechanical forces

Changes in Histoanatomical Distribution Of Types I, III And V Collagen Promote Adaptative Remodeling in Posterior Tibial Tendon Rupture

INTRODUCTION: Posterior tibial tendon dysfunction is a common cause of adult flat foot deformity, and its etiology is unknown. PURPOSE: In this study, we characterized the morphologic pattern and distribution of types I, III and V collagen in posterior tibial tendon dysfunction. METHOD: Tendon samples from patients with and without posterior tibial tendon dysfunction were stained by immunofluorescence using antibodies against types I, III and V collagen. RESULTS: Control samples showed that type V deposited near the vessels only, while surgically obtained specimens displayed type V collagen surrounding other types of collagen fibers in thicker adventitial layers. Type III collagen levels were also increased in pathological specimens. On the other hand, amounts of collagen type I, which represents 95% of the total collagen amount in normal tendon, were decreased in pathological specimens. CONCLUSION: Fibrillogenesis in posterior tibial tendon dysfunction is altered due to higher expression of types III and V collagen and a decreased amount of collagen type I, which renders the originating fibrils structurally less resistant to mechanical forces

Association between decreases in type V collagen and apoptosis in mouse lung chemical carcinogenesis: a preliminary model to study cancer cell behavior

OBJECTIVE: The importance of type V collagen and its relationships with other types of collagen and with vascular and epithelial apoptosis were studied in a model of chemical carcinogenesis in the mouse lung. METHODS: Two groups of male Balb/c mice were studied: a) animals that received two intraperitoneal doses of 3 g/kg urethane carcinogen (urethane group = 24); and b) animals submitted to a sham procedure, comparable to the test group (control group = 7). Both groups were sacrificed after 120 days. In situ detection of apoptosis, immunohistochemistry, immunofluorescence and histomorphometry were used to evaluate the fraction occupied by the tumor, vascular and epithelial apoptosis, and type V, III and I collagen fibers in the lung parenchyma from both groups. RESULTS: The lung parenchyma from the urethane group showed low fractions of vascular and epithelial apoptosis as well as reduced type V collagen fibers when compared to the control group. A significant direct association was found between type V and III collagen fibers and epithelial apoptosis, type V collagen fibers and vascular apoptosis, and type V and type I collagen fibers. CONCLUSION: The results show that a direct link between low amounts of type V collagen and decreased cell apoptosis may favor cancer cell growth in the mouse lung after chemical carcinogenesis, suggesting that strategies aimed at preventing decreased type V collagen synthesis or local responses to reduced apoptosis may have a greater impact in lung cancer control

Collagen V-induced nasal tolerance downregulates pulmonary collagen mRNA gene and TGF-beta expression in experimental systemic sclerosis

<p>Abstract</p> <p>Background</p> <p>The purpose of this study was to evaluate collagen deposition, mRNA collagen synthesis and TGF-beta expression in the lung tissue in an experimental model of scleroderma after collagen V-induced nasal tolerance.</p> <p>Methods</p> <p>Female New Zealand rabbits (N = 12) were immunized with 1 mg/ml of collagen V in Freund's adjuvant (IM). After 150 days, six immunized animals were tolerated by nasal administration of collagen V (25 μg/day) (IM-TOL) daily for 60 days. The collagen content was determined by morphometry, and mRNA expressions of types I, III and V collagen were determined by Real-time PCR. The TGF-beta expression was evaluated by immunostaining and quantified by point counting methods. To statistic analysis ANOVA with Bonferroni test were employed for multiple comparison when appropriate and the level of significance was determined to be <it>p </it>< 0.05.</p> <p>Results</p> <p>IM-TOL, when compared to IM, showed significant reduction in total collagen content around the vessels (0.371 ± 0.118 vs. 0.874 ± 0.282, <it>p </it>< 0.001), bronchioles (0.294 ± 0.139 vs. 0.646 ± 0.172, <it>p </it>< 0.001) and in the septal interstitium (0.027 ± 0.014 vs. 0.067 ± 0.039, <it>p </it>= 0.026). The lung tissue of IM-TOL, when compared to IM, showed decreased immunostaining of types I, III and V collagen, reduced mRNA expression of types I (0.10 ± 0.07 vs. 1.0 ± 0.528, p = 0.002) and V (1.12 ± 0.42 vs. 4.74 ± 2.25, p = 0.009) collagen, in addition to decreased TGF-beta expression (p < 0.0001).</p> <p>Conclusions</p> <p>Collagen V-induced nasal tolerance in the experimental model of SSc regulated the pulmonary remodeling process, inhibiting collagen deposition and collagen I and V mRNA synthesis. Additionally, it decreased TGF-beta expression, suggesting a promising therapeutic option for scleroderma treatment.</p

Unusual remodeling of the hyalinization band in vulval lichen sclerosus by type V collagen and ECM 1 protein

OBJECTIVES: The vulva is the primary site affected in lichen sclerosus, a chronic dermatosis in women that is histologically characterized by a zone of collagen remodeling in the superior dermis. The normal physiological properties of the vulva depend on the assembly of collagen types I (COLI), III (COLIII) and V (COLV), which form heterotypic fibers, and extracellular matrix protein interactions. COLV regulates the heterotypic fiber diameter, and the preservation of its properties is important for maintaining normal tissue architecture and function. In the current work, we analyzed the expression of COLV and its relationship with COLI, COLIII, elastic fibers and extracellular matrix protein 1 in vulvar biopsies from patients with lichen sclerosus. METHODS: Skin biopsies from 21 patients with lichen sclerosus, classified according to Hewitt histological criteria, were studied and compared to clinically normal vulvar tissue (N=21). Morphology, immunohistochemistry, immunofluorescence, 3D reconstruction and morphometric analysis of COLI, COLIII, COLV deposition, elastic fibers and extracellular matrix 1 expression in a zone of collagen remodeling in the superior dermis were performed. RESULTS: A significant decrease of elastic fibers and extracellular matrix 1 protein was present in the hyalinization zone of lichen sclerosus compared to healthy controls. The non-homogeneous distribution of collagen fibers visualized under immunofluorescence in the hyalinization zone of lichen sclerosus and control skin was confirmed by histomorphometry. Lichen sclerosus dermis shows a significant increase of COLI, COLIII and COLV expression compared to the healthy controls. Significant inverse associations were found between elastic fibers and COLV and between COLV and extracellular matrix 1 expression. A direct association was found between elastic fiber content and extracellular matrix 1 expression. Tridimensional reconstruction of the heterotypic fibers of the lichen sclerosus zone of collagen remodeling confirmed the presence of densely clustered COLV. CONCLUSIONS: Increased deposition of abnormal COLV and its correlation with extracellular matrix 1 and elastic fibers suggest that COLV may be a trigger in the pathogenesis of lichen sclerosus

Bone Plasticity in Response to Exercise Is Sex-Dependent in Rats

Purpose: To characterize the potential sexual dimorphism of bone in response to exercise.Methods: Young male and female Wistar rats were either submitted to 12 weeks of exercise or remained sedentary. the training load was adjusted at the mid-trial (week 6) by the maximal speed test. A mechanical test was performed to measure the maximal force, resilience, stiffness, and fracture load. the bone structure, formation, and resorption were obtained by histomorphometric analyses. Type I collagen (COL I) mRNA expression and tartrate-resistant acid phosphatase (TRAP) mRNA expression were evaluated by quantitative real-time PCR (qPCR).Results: the male and female trained rats significantly improved their maximum speed during the maximal exercise test (main effect of training; p<0.0001). the male rats were significantly heavier than the females, irrespective of training (main effect of sex; p<0.0001). Similarly, both the weight and length of the femur were greater for the male rats when compared with the females (main effect of sex; p<0.0001 and p<0.0001, respectively). the trabecular volume was positively affected by exercise in male and female rats (main effect of training; p = 0.001), whereas the trabecular thickness, resilience, mineral apposition rate, and bone formation rate increased only in the trained males (within-sex comparison; p<0.05 for all parameters), demonstrating the sexual dimorphism in response to exercise. Accordingly, the number of osteocytes increased significantly only in the trained males (within-sex comparison; p<0.05). Pearson's correlation analyses revealed that the COL I mRNA expression and TRAP mRNA expression were positively and negatively, respectively, related to the parameters of bone remodeling obtained from the histomorphometric analysis (r = 0.59 to 0.85; p<0.05).Conclusion: Exercise yielded differential adaptations with respect to bone structure, biomechanical proprieties, and molecular signaling in male and female rats.Univ São Paulo, Sch Med, Div Nephrol, São Paulo, BrazilUniv São Paulo, Sch Phys Educ & Sport, Dept Sports, São Paulo, BrazilUniv São Paulo, Inst Biomed Sci, Dept Anat, São Paulo, BrazilUniv São Paulo, Sch Med, Div Rheumatol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiol Sci, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiol Sci, São Paulo, BrazilWeb of Scienc

Intravenous glutamine decreases lung and distal organ injury in an experimental model of abdominal sepsis

Introduction The protective effect of glutamine, as a pharmacological agent against lung injury, has been reported in experimental sepsis; however, its efficacy at improving oxygenation and lung mechanics, attenuating diaphragm and distal organ injury has to be better elucidated. In the present study, we tested the hypothesis that a single early intravenous dose of glutamine was associated not only with the improvement of lung morpho-function, but also the reduction of the inflammatory process and epithelial cell apoptosis in kidney, liver, and intestine villi. Methods Seventy-two Wistar rats were randomly assigned into four groups. Sepsis was induced by cecal ligation and puncture surgery (CLP), while a sham operated group was used as control (C). One hour after surgery, C and CLP groups were further randomized into subgroups receiving intravenous saline (1 ml, SAL) or glutamine (0.75 g/kg, Gln). At 48 hours, animals were anesthetized, and the following parameters were measured: arterial oxygenation, pulmonary mechanics, and diaphragm, lung, kidney, liver, and small intestine villi histology. At 18 and 48 hours, Cytokine-Induced Neutrophil Chemoattractant (CINC)-1, interleukin (IL)-6 and 10 were quantified in bronchoalveolar and peritoneal lavage fluids (BALF and PLF, respectively). Results CLP induced: a) deterioration of lung mechanics and gas exchange; b) ultrastructural changes of lung parenchyma and diaphragm; and c) lung and distal organ epithelial cell apoptosis. Glutamine improved survival rate, oxygenation and lung mechanics, minimized pulmonary and diaphragmatic changes, attenuating lung and distal organ epithelial cell apoptosis. Glutamine increased IL-10 in peritoneal lavage fluid at 18 hours and bronchoalveolar lavage fluid at 48 hours, but decreased CINC-1 and IL-6 in BALF and PLF only at 18 hours. Conclusions In an experimental model of abdominal sepsis, a single intravenous dose of glutamine administered after sepsis induction may modulate the inflammatory process reducing not only the risk of lung injury, but also distal organ impairment. These results suggest that intravenous glutamine may be a potentially beneficial therapy for abdominal sepsis.Centres of Excellence Program (PRONEX-FAPERJ)Brazilian Council for Scientific and Technological Development (CNPq)Carlos Chagas FilhoRio de Janeiro State Research Supporting Foundation (FAPERJ)Sao Paulo State Research Supporting Foundation (FAPESP

Colágeno na cartilagem osteoartrótica

A cartilagem articular é um tecido altamente especializado, composto por células, os condrócitos, e um conjunto de macromoléculas, como o colágeno e os proteoglicanos. O colágeno é uma proteína fibrilar que garante resistência ao tecido, enquanto os proteoglicanos têm a função de mola biológica, sendo responsáveis pela compressibilidade da cartilagem. A complexa interação entre estas duas proteínas garante a elasticidade. Estas características específicas da cartilagem são essenciais para amortecer as grandes forças de impacto a que as articulações diartrodiais estão submetidas, sem muito gasto de energia, visto tratar-se de um tecido avascular. Em processos artrósicos ocorre um desequilíbrio entre a produção de componentes da matriz extracelular e destruição pelas metaloproteases, levando à degradação e perda do tecido cartilaginoso. A fase inicial da osteoartrose é marcada por perda de fragmentos de proteoglicanos para o líquido sinovial, aumento dos colágenos tipo II e tipo VI, aparecimento dos colágenos I e III, não típicos da cartilagem, e diminuição do colágeno tipo IX, que é importante para manter a integridade da matriz extracelular, além do entumescimento da cartilagem. Como conseqüência, a cartilagem perde suas características específicas, levando a alterações na função articular. A evolução da doença promove diminuição significativa das proteínas, até mesmo do colágeno tipo XI, que tem localização mais interna na estrutura da fibrila heterotípica, e, portanto levando até a exposição do osso. Até o momento, o tratamento da osteoartrose está baseado principalmente no controle da dor e/ou inflamação, não diminuindo ou impedindo a degradação da cartilagem articular. Neste aspecto a perspectiva de tratamento futuro da osteoartrose estaria na utilização de inibidores das metaloproteases associadas a condroprotetores interferindo no "turnover" da cartilagem e impedindo, deste modo, o processo de degradação

Anticorpos antimatriz extracelular e antiaorta em pacientes com arterite de Takayasu

Os componentes de matriz extracelular têm sido amplamente pesquisados nos últimos anos quanto ao seu papel na patogênese de diversas doenças difusas do tecido conjuntivo e síndromes vasculíticas. No caso da arterite de Takayasu, muito pouco se sabe sobre o assunto e são propostas teorias relacionadas com a participação da imunidade celular ou humoral para explicar a causa desta doença. Neste sentido, avaliamos a imunidade humoral nesta patologia. OBJETIVO: Pesquisar anticorpos contra componentes da matriz extracelular, incluindo a identificação de anticorpos anticolágeno e antiaorta. MÉTODOS: Soros de 13 pacientes com arterite de Takayasu e de 8 pacientes normais foram utilizados para pesquisa de auto-anticorpos anticolágeno tipos I, III, IV e V e antiaorta pelo método ELISA. RESULTADOS: Soros dos pacientes com arterite de Takayasu revelaram-se negativos para colágenos dos tipos III e IV e apenas um paciente apresentou positividade para os tipos I e V, enquanto todos os soros de pacientes com arterite de Takayasu revelaram-se negativos para anticorpos anti-aorta. CONCLUSÕES: Nossos dados demonstraram que as freqüências de anticorpos anticolágenos dos tipos I, III, IV e V não estiveram significativamente aumentadas no soro de pacientes com arterite de Takayasu, assim como os anticorpos antiextrato de aorta, sugerindo que a etiopatogenia desta vasculite esteja possivelmente relacionada com distúrbio da imunidade celular

ROLE OF FOCAL ADHESION KINASE IN LUNG REMODELING OF ENDOTOXEMIC RATS

Despite significant advances in the care of critically ill patients, acute lung injury continues to be a complex problem with high mortality. The present study was designed to characterize early lipopolysaccharide (LPS)-induced pulmonary injury and small interfering RNA targeting focal adhesion kinase (FAK) as a possible therapeutic tool in the septic lung remodeling process. Male Wistar rats were assigned into endotoxemic group and control group. Total collagen deposition was performed 8, 16, and 24 h after LPS injection. Focal adhesion kinase expression, interstitial and vascular collagen deposition, and pulmonary mechanics were analyzed at 24 h. Intravenous injection of small interfering RNA targeting FAK was used to silence expression of the kinase in pulmonary tissue. Focal adhesion kinase, total collagen deposition, and pulmonary mechanics showed increased in LPS group. Types I, III, and V collagen showed increase in pulmonary parenchyma, but only type V increased in vessels 24 h after LPS injection. Focal adhesion kinase silencing prevented lung remodeling in pulmonary parenchyma at 24 h. In conclusion, LPS induced a precocious and important lung remodeling. There was fibrotic response in the lung characterized by increased amount in total and specific-type collagen. These data may explain the frequent clinical presentation during sepsis of reduced lung compliance, oxygen diffusion, and pulmonary hypertension. The fact that FAK silencing was protective against lung collagen deposition underscores the therapeutic potential of FAK targeting by small interfering RNA.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo ([FAPESP] Sao Paulo Research Foundation) [09/03338-7, 06/00443-6, CNPq-470744/2004-9]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo ( Sao Paulo Research Foundation