Histomorphometric analysis of cutaneous remodeling in the early stage of the scleroderma model.

INTRODUCTION/OBJECTIVES: Systemic sclerosis, or scleroderma, is a rheumatic disease characterized by autoimmunity, vasculopathy, and fibrosis of the skin and several internal organs. In the present study, our aim was to assess the skin alterations in animals with scleroderma during the first stages of disease induction. METHODS: To induce scleroderma, female New Zealand rabbits (n = 12) were subcutaneously immunized with 1 mg/ml of collagen V (Col V) in complete Freund's adjuvant, twice with a thirty-day interval. Fifteen days later, the animals received an intramuscular booster with type V collagen in incomplete Freund's adjuvant, twice with a fifteen-day interval. The control group was inoculated with 1 ml of 10 mM acetic acid solution diluted with an equal amount of Freund's adjuvant. Serial dorsal skin biopsies were performed at 7, 15, and 30 days and stained with H&E, Masson's trichrome and Picrosírius for morphological and morphometric analyses. RESULTS: Immunized rabbits presented a significant increase in collagen in skin collected seven days after the first immunization (p=0.05). CONCLUSION: The results from this experimental model may be very important to a better understanding of the pathogenic mechanisms involved in the beginning of human SSc. Therapeutic protocols to avoid early remodeling of the skin may lead to promising treatments for SSc in the future.

Abnormal collagen deposition in synovia after collagen type V immunization in rabbits.

Sinovitis in Scleroderma (SSc) is rare, usually aggressive and fully resembles rheumatoid arthritis. Experimental models of SSc have been used in an attempt to understand its pathogenesis. Previous studies done in our laboratory had already revealed the presence of a synovial remodeling process in rabbits immunized with collagen V. To validate the importance of collagen type V and to explore the quantitative relationship between this factor and synovia remodeling as well as the relationship between collagen type V and other collagens, we studied the synovial tissue in immunized rabbits. Rabbits (N=10) were immunized with collagen V plus Freund's adjuvant and compared with animals inoculated with adjuvant only (N=10). Synovial tissues were submitted to histological analysis, immunolocalization to collagen I, III and V and biochemical analysis by eletrophoresis, immunoblot and densitometric method. The synovial tissue presented an intense remodeling process with deposits of collagen types I, III and V after 75 and 120 days of immunization, mainly distributed around the vessels and interstitium of synovial extracellular matrix. Densitometric analysis confirmed the increased synthesis of collagen I, III and V chains (407.69+/-80.31; 24.46+/-2.58; 70.51+/-7.66, respectively) in immunized rabbits when compared with animals from control group (164.91+/-15.67; 12.89+/-1.05; 32+/-3.57) (p<0.0001). We conclude that synovial remodeling observed in the experimental model can reflect the articular compromise present in patients with scleroderma. Certainly, this experimental model induced by collagen V immunization will bring new insights in to pathogenic mechanisms and allow the testing of new therapeutic strategies to ameliorate the prognosis for scleroderma patients.

Collagen V nasal tolerance in experimental model of systemic sclerosis.

Our aim was to study skin remodeling and autoantibody production in an experimental model of scleroderma (SSc), following nasal tolerance with human type V collagen (Col V). Female New Zealand rabbits (n = 12) were immunized with two doses of 1 mg/ml of Col V in complete Freund's adjuvant and additional two boosters in incomplete Freund's adjuvant to induce SSc. After 150 days, half of these immunized rabbits were submitted to type V collagen-induced tolerance receiving a daily nasal administration of 25 mug of Col V. Control animals (n = 6) were only submitted to type V collagen-induced tolerance. Serial skin biopsies were performed on days 0, 150 and 210, and stained with H&E, Masson's trichrome and Picrosirius for morphological and morphometric analysis. Types I, III and V collagen were identified by immunofluorescence. The animals' serum samples were collected to determine anti types I, III, IV and V collagen and antinuclear antibodies (ANA). Skin biopsies from immunized animals confirmed SSc morphology as previously described, such as progressive decrease of papillary dermis, appendages atrophy, increased type I, III and V collagen deposition. Rabbits with Col V-induced nasal tolerance showed reduction of skin involvement, with significant decrease of collagen amount. Humoral immune response did not change with nasal tolerance. Collagen V nasal tolerance promotes regression of skin remodeling process in an experimental model of SSc. We suggest that nasal tolerance with type V collagen can be a promising therapeutic option to treat scleroderma patients.

Interstitial and vascular type V collagen morphologic disorganization in usual interstitial pneumonia.

Recent evidence suggests that type V collagen plays a role in organizing collagen fibrils, thus maintaining fibril size and spatial organization uniform. In this study we sought to characterize the importance of type V collagen morphological disorganization and to study the relationship between type V collagen, active remodeling of the pulmonary vascular/parenchyma (fibroblastic foci), and other collagen types in usual interstitial pneumonia (UIP). We examined type V collagen and several other collagens in 24 open lung biopsies with histological pattern of UIP from patients with idiopathic pulmonary fibrosis (IPF). We used immunofluorescence, morphometry, and three-dimensional reconstruction to evaluate the amount of collagen V and its interaction with the active remodeling progression in UIP, as well as types I and III collagen fibers. Active remodeling progression was significantly related to type V collagen density (p<0.05), showing a gradual and direct increase to minimal, moderate, and severe fibrosis degree in UIP and in the three different areas: normal, intervening, and mural-organizing fibrosis in UIP. Parenchymal changes were characterized by morphological disorganization of fibrillar collagen with diverse disarray and thickness when observed by three-dimensional reconstruction. We concluded that in the different temporal stages of UIP, vascular/parenchyma collagen type V is increased, in disarray, and is the most important predictor of survival.

Scleroderma-like remodeling induced by type V collagen.

Recently, we discovered that New Zealand rabbits immunized with human type V collagen plus Freund's adjuvant present fibrosis and vasculitis of organs usually affected by systemic sclerosis. In this way, we studied the fibrillogenesis process to identify possible factors involved in altered remodeling observed in this scleroderma-like model. Additionally, we have done a very preliminary comparison with human skins obtained from scleroderma patients (n=3). Female New Zealand rabbits (n=10) were immunized subcutaneously with two doses of 1 mg collagen V (COL V) plus complete Freund's adjuvant for a 30-day interval, followed by two additional intramuscular booster immunizations in incomplete Freund's adjuvant for a 15-day interval. Animals from control group (n=10), were only inoculated with complete and incomplete Freund's adjuvant given at same conditions of COL V. Histological analysis of skins from animals and patients were done by Masson's trichrome staining, and immunofluorescence method to detect collagen fibers and interactions of types I, III and V collagen in the remodeling process. The analysis of animal skins showed collagen fibril deposits in the dermis after 7 days of sensibilization and an increase in these deposits after 75 and 120 days, respectively. Skin thickness and atrophy of sebaceous and sweat glands were progressively more intense in late sacrificed animals and correlated with increased amount of collagen deposition. Surprisingly, type V collagen was overexpressed both in animals and patients, forming dense and atypical collagen fibers in the dermis. We suggest that this anomalous expression of morphologically different type V collagen could justify the remodeling observed in scleroderma plaque.