Effects of glucose on collagen mRNA levels and collagen secretion in EAhy 926 endothelial cell line.

Diabetes mellitus (DM) is a complex metabolic disease associated with increased accumulation of extracellular matrix by endothelial cells and contributing to vascular complications of long-standing diabetes. On the other hand, DM is also associated with decreased accumulation of extracellular matrix in granulation tissue, which is suggested to be a consequence of impaired angiogenesis. The role of hyperglycemia in these situations is not fully understood.

Effects of glucose on collagen mRNA levels and collagen secretion in EAhy 926 endothelial cell line.

Diabetes mellitus (DM) is a complex metabolic disease associated with increased accumulation of extracellular matrix by endothelial cells and contributing to vascular complications of long-standing diabetes. On the other hand, DM is also associated with decreased accumulation of extracellular matrix in granulation tissue, which is suggested to be a consequence of impaired angiogenesis. The role of hyperglycemia in these situations is not fully understood.

Feasibility of genetic and immunological prediction of type I diabetes in a population-based birth cohort.

Aims/hypothesis: Population-wide genetic screening of susceptibility to multifactorial diseases will become relevant as knowledge of the pathogenesis of these diseases increases and preventive interventions are identified.

Methods: Feasibility and acceptance of neonatal genetic screening for Type I (insulin-dependent) diabetes mellitus susceptibility and adherence of the at-risk children to frequent autoantibody follow-up were studied. Screening was offered to all families.

Enterovirus infection as a risk factor for beta-cell autoimmunity in a prospectively observed birth cohort: the Finnish Diabetes Prediction and Prevention Study.

Previous studies suggest that enterovirus infections may initiate and accelerate beta-cell damage years before the clinical manifestation of type 1 diabetes. We have now analyzed the role of enterovirus infections in the initiation of autoimmunity in children who have tested positive for diabetes-associated autoantibodies in a prospective study starting at birth (the Finnish Diabetes Prediction and Prevention Study). The frequency of enterovirus infections was studied using both serology and testing for the presence of enterovirus RNA in the sera of 21 children who developed and retained autoantibodies and in 104 control subjects chosen from the same study cohort and matched for the time of birth, sex, and HLA alleles determining genetic diabetes susceptibility.

Cow's milk formula feeding induces primary immunization to insulin in infants at genetic risk for type 1 diabetes.

Insulin autoantibodies (IAAs) often appear as the first sign of islet cell autoimmunity in prediabetic children. Because cow's milk contains bovine insulin, we followed the development of insulin-binding antibodies in children fed with cow's milk formula. Bovine insulin- and human insulin-binding antibodies by enzyme immunoassay and IAA by radioimmunoassay were analyzed in 200 infants carrying HLA-DQB1*0302 but no protective alleles who participated in a Finnish population-based birth-cohort study.

Extracellular matrix of peripheral nerves in diabetes.

Peripheral nerves are susceptible to develop multiple changes in their morphology and biochemical composition as consequences of diabetes mellitus. This review focuses on diabetes-induced alterations of the extracellular matrix of the peripheral nerves, and on the potential molecular mechanisms causing these changes. The interest towards the extracellular matrix of peripheral nerves of diabetic patients is highlighted by the fact that the extracellular matrix does not only mechanically support the cells which it surrounds, but it also regulates their behavior through specific interactions mediated via molecules on the cell surface, such as integrin receptors and cell surface proteoglycans.

Type VI collagen gene expression in experimental liver fibrosis: quantitation and spatial distribution of mRNAs, and immunodetection of the protein.

Type VI collagen is a minor but essential matrix component in the liver. In this study, we utilized an acute and a chronic injury model to clarify the process of liver fibrosis in rats by administration of carbon tetrachloride. Collagen gene expression, with particular emphasis on type VI collagen, was studied by molecular hybridization techniques.

A fibroblast cell line cultured from a hypertrophic scar displays selective downregulation of collagen gene expression: barely detectable messenger RNA levels of the pro alpha 1(III) chain of type III collagen.

The present study was designed to investigate the expression of type I, III and VI collagens by a fibroblast cell line initiated from a hypertrophic scar. The same tissue has previously been demonstrated to display markedly elevated expression of type I and III collagen mRNAs in vivo. Unexpectedly, slot-blot and Northern hybridizations revealed a barely detectable steady-state level of pro alpha 1(III) collagen chain mRNA in cultured hypertrophic scar fibroblasts.

Normal and hypertrophic scars: quantification and localization of messenger RNAs for type I, III and VI collagens.

The expression of type I, III and VI collagens was studied in nine normal and two hypertrophic scars using slot-blot and in situ hybridization techniques. Slot-blot hybridization indicated that the steady-state levels of pro alpha 1(I) and pro alpha 1(III) collagen chain mRNAs were moderately elevated in two of the nine normal scars, whereas the two hypertrophic scars analysed displayed markedly elevated mRNA levels when compared with normal skin. The mRNA levels of alpha 2(VI) collagen chain were only slightly elevated in both types of scars studied.

Connective tissue metabolism in diabetic peripheral nerves.

Diabetes mellitus is associated with multiple connective tissue changes, such as generalized thickening of basement membranes. These alterations are suspected of contributing to the development of diabetic long-term complications encountered in many organs, including kidney, eye and peripheral nerves. The latter tissue, however, has gained relatively little attention with respect to connective tissue changes associated with diabetes.

Expression of type I, III, and VI collagen mRNAs in experimentally injured porcine intervertebral disc.

Young domestic pigs were incised with a scalpel blade into the anterior part of annulus fibrosus of lumbar discs in order to study the reparative processes in the annulus fibrosus and the secondary reactions in the nucleus pulposus. Northern and slot-blot hybridizations were used to investigate type I, III, and VI collagen gene expression in the disc tissue. For this purpose a method for RNA isolation was modified so as to be applicable to the intervertebral disc, which has a low cell density and a high proteoglycan content in its extracellular matrix.

Hyperglycemic glucose concentrations up-regulate the expression of type VI collagen in vitro. Relevance to alterations of peripheral nerves in diabetes mellitus.

Electron microscopy of peripheral nerves obtained from two diabetic patients revealed large deposits of microfibrils and the presence of Luse bodies in the vicinity of perineurial cells. Microfibrils were found to accumulate also in the sciatic nerves of diabetic BB rats; these microfibrillar deposits were shown to contain type VI collagen by immunoelectron microscopy. Connective tissue cells cultured from rat sciatic nerves were exposed to high glucose concentrations.

Expression of glucose transporter 1 in adult and developing human peripheral nerve.

Northern hybridization of total RNA isolated from adult human sciatic nerve demonstrated a readily detectable hybridization signal for glucose transporter 1 (GLUT 1) mRNA. Western blot analysis demonstrated that GLUT 1 proteins extracted from adult human and from mature rat sciatic nerves had different electrophoretical mobilities. The migration positions of human and rat GLUT 1 proteins corresponded to 60-70 kDa and 55-60 kDa, respectively, as estimated by markers with known molecular masses.

Glucose transporters of rat peripheral nerve. Differential expression of GLUT1 gene by Schwann cells and perineural cells in vivo and in vitro.

Expression of GLUTs in rat peripheral nerve was first studied at the mRNA level with Northern transfer analysis with cDNAs specific for GLUT1, GLUT2, GLUT3, and GLUT4. GLUT1 mRNA was the only GLUT mRNA detectable in rat sciatic nerve. In situ hybridization localized this mRNA to the perineurium and to some endo- and epineurial capillaries.

Presence of type I and VI collagen mRNAs in endothelial cells in cutaneous neurofibromas.

In situ hybridization and peroxidase anti-peroxidase immunodetection were used in the same tissue sections to elucidate the spatial distribution of collagen gene expression in cutaneous neurofibromas, particularly in relation to blood vessels; the latter structures were identified by the presence of factor VIII-related antigen. The data indicate a clear relationship between the vascular structures and sites of locally elevated expression of type I and VI collagen genes. Specifically, some, but not all, blood vessels were surrounded by stromal cells highly active in expressing pro alpha 1(I) and alpha 2(VI) collagen genes.

Increased matrix gene expression by glucose in rat neural connective tissue cells in culture.

The effects of different glucose concentrations on the expression of extracellular matrix genes were examined in primary cell cultures initiated from sciatic nerves of nondiabetic Sprague-Dawley rats. The cells were incubated in medium containing 5.5, 15, or 25 mM D-glucose, and the expression of type I and IV collagens, laminin, and fibronectin genes was examined at mRNA steady-state levels by Northern hybridizations.

Segmental neurofibromatosis: immunocytochemical analysis of cutaneous lesions.

Cutaneous lesions from three patients with segmental neurofibromatosis were evaluated. Routine histologic studies revealed the presence of redimentary neural structures within an abundant collagenous matrix. The majority of the cells in all three cases expressed S-100 protein, suggesting their identity as Schwann cells.

Diabetes induces the formation of large diameter collagen fibrils in the sciatic nerves of BB rats.

Diabetes mellitus (DM) is known to be associated with widespread connective tissue changes. However, the connective tissue of peripheral nerves in diabetes has gained little attention. Thickening of the basement membranes of Schwann, perineurial and endothelial cells suggests a perturbation in the metabolism of type IV collagen.