Co-localization of transforming growth factor beta 2 with alpha 1(I) procollagen mRNA in tissue sections of patients with systemic sclerosis.

The role of transforming growth factor beta 2 (TGF-beta 2) in the pathogenesis of systemic sclerosis (SSc) was investigated by in situ hybridization of skin biopsies from six patients with SSc. Two patients with acute systemic lupus erythematosis (SLE), one with acute dermatomyositis (DM), and three healthy individuals were used as controls. TGF-beta 2 mRNA was found to be co-localized with pro alpha 1(I) collagen expression around dermal blood vessels in all patients with the inflammatory stage of SSc, whereas there was no expression of either gene in the dermis of patients in the fibrotic stage, the SLE patients or the normal controls. These findings provide evidence that TGF-beta 2 released by inflammatory cells around blood vessels may play a role in mediating the collagen gene disregulation in fibrosis.

Steady-state mRNA levels of collagens I, III, fibronectin, and collagenase in skin biopsies of systemic sclerosis patients.

Total RNA was extracted from skin biopsies of nine patients suffering from systemic sclerosis (SSc). Steady-state mRNA levels of collagen alpha 1(I) and alpha 1(III), collagenase, fibronectin, and beta-actin were studied using specific cDNA probes and compared to those of 12 sex- and age-matched healthy individuals. There was a more than three-fold elevation of collagen I mRNA levels in SSc skin compared to controls. No difference was found, however, for collagen III, collagenase, and fibronectin mRNA levels in SSc and control biopsies. The selective increase of collagen alpha 1(I) mRNA levels indicates a specific alteration of fibroblast metabolism in scleroderma. Analysis of mRNA levels in skin biopsies might not only offer a direct approach to the understanding of the pathophysiology of SSc, but also facilitate the monitoring of fibrotic activity in SSc patients during therapeutic trials.

Localization of collagen alpha 1(I) gene expression during wound healing by in situ hybridization.

The cellular localization of collagen alpha 1(I) chain gene expression during wound healing in rats was investigated using in situ hybridization. Activation of collagen gene expression was first found within fibroblastic cells around the deep layers of the granulation tissue as early as 16 h post wounding. Heavily labeled cells were also detected near the intact wound edge and around hair follicles. At day 6 intense alpha 1(I) collagen gene expression was found within most cells of the granulation tissue and after day 8 most of the activity was localized to cells directly underneath the epidermis. 26 d after the induction of the wounds hardly any alpha 1(I) collagen gene expression could be demonstrated, which indicates a close, time-dependent control of collagen synthesis during repair processes.

Cytokines alter mRNA steady state levels for basement membrane proteins in human skin fibroblasts.

Keratinocytes and fibroblasts synthesize basement membrane proteins and even contribute to the formation of basement membrane structures following injury or tissue damage. Under these conditions many cellular functions are regulated by mediators e.g. transforming growth factor-beta, tumor necrosis factor alpha, interferon-gamma or interleukin-1 alpha. We therefore describe here their influence on synthesis of basement membrane proteins in human skin fibroblasts. A comparative analysis of mRNA steady levels coding for BM-40, nidogen, laminin B1 and B2 chains and collagen IV in fibroblasts, in primary human keratinocytes and a epidermal cell line grown in monolayer culture demonstrated that the highest amounts were present in human fibroblasts. Interferon-gamma reduces all mRNA steady state levels dose dependently in comparison to the control, while transforming growth factor-beta simultaneously induces BM-40, alpha 1 and alpha 2 (IV) collagen mRNAs. TGF-beta, however, has no effect on nidogen and laminin mRNA levels. Interleukin-1 alpha and tumor necrosis factor alpha do not affect the mRNA levels of most basement membrane proteins. However, the alpha 1 (IV) collagen mRNA is upregulated by both cytokines to 300%. These data demonstrate a specific control of the expression of several basement membrane proteins by cytokines and indicate that fibroblasts could contribute to basement membrane formation during wound healing and tissue repair.

[Changes in collagen connective tissue and fibroblasts in aging]. / Veränderungen des kollagenen Bindegewebes und der Fibroblasten während des Alterns.

Some of the characteristic features of aging skin, such as wrinkling, loss of elasticity, and atrophy, can largely be attributed to dermal changes. The amount of collagen in the skin decreases, while the cross linking increases, and the solubility of collagen is reduced. The total number of fibroblasts decreases, and their metabolism shows characteristic alterations. Some of the functions of fibroblasts in aging skin, such as the synthesis of protein and collagen, but also proliferation and chemotaxis, can be investigated by means of in vitro models. In addition, various syndromes of premature aging (e.g. progeria, Werner's syndrome) have proved useful models and have contributed considerably to the understanding of aging processes.

[The basement membrane and its significance in congenital and acquired diseases of the skin]. / Die Basalmembran und ihre Bedeutung bei angeborenen und erworbenen Erkrankungen der Haut.

Basal membranes are an ubiquitous component of all human organs and fulfil a large variety of functions. They separate epithelial from mesenchymal tissue and control the passage of substances, of inflammatory as well as tumor cells. They form the extracellular cytoskeleton, regulate growth processes, and play an important part in wound healing. Ultrastructurally, the lamina densa can be distinguished from the lamina lucida. Anchoring fibrils connect the basal membrane of the dermoepidermal junction with the underlying dermis, while anchoring plates connect it with the epidermal cells. During the last few years, various components of the basal membrane have been biochemically analyzed. Different proteins were characterized, and their corresponding morphological structure could be identified. The growing knowledge regarding the structure and composition of the dermo-epidermal junction has led to a better understanding of many diseases involving this structure, in particular inborn and acquired bullous diseases, but also that of the role of the basal membrane in metastasis and tumor invasions. The characterization of antigens in bullous diseases with circulating antibodies has led to exact diagnostic criteria concerning the often overlapping disorders and allows, e.g., the differentiation between bullous pemphigoid and epidermolysis bullosa acquisita.

In situ hybridization--a useful tool for studies on collagen gene expression in cell culture as well as in normal and altered tissue.

We report the application of antisense RNA probes for in situ hybridization to identify collagen type I and type III mRNA synthesizing fibroblasts under in vitro and in vivo conditions in normal and wounded human skin. Non-specific hybridization was excluded by specific distribution patterns of alpha 1(I)- and alpha 1(III) probes in mouse fetuses. In addition, the specificity of hybridization was checked by sense probes, radioactively labelled transcripts of Gemini vectors and a keratin probe. In normal skin weakly activated fibroblasts were sparsely scattered within the dermis, while in wound healing processes mRNA both for alpha 1(I) and for alpha 1(III) was dramatically increased, thus suggesting that collagen synthesis is at least partly regulated at a pretranslational level. In addition, the intensity of the labelling, as defined by image analysis and the distribution pattern of collagen mRNA synthesizing cells, provide strong evidence that wound healing by primary intention starts within the deep dermis.

Sickle cell disease in Orissa State, India.

A study of 131 patients with homozygous sickle cell (SS) disease in Orissa State, India, indicated that, compared with Jamaican patients, Indian patients have higher frequencies of alpha thalassaemia, higher fetal haemoglobin, total haemoglobin, and red cell counts, and lower mean cell volume, mean cell haemoglobin concentration, and reticulocyte counts. Indian patients have a greater frequency and later peak incidence of splenomegaly, and hypersplenism is common. Painful crises and dactylitis are not uncommon in Indian patients but chronic leg ulceration is rare. Homozygous sickle cell disease in Orissa is similar to that in the Eastern Province of Saudi Arabia and is very different from that in populations of West African origin.