Urokinase receptor expression on human microvascular endothelial cells is increased by hypoxia: Implications for capillary-like tube formation in a fibrin matrix

Hypoxia stimulates angiogenesis, the formation of new blood vessels. This study evaluates the direct effect of hypoxia (1% oxygen) on the angiogenic response of human microvascular endothelial cells (hMVECs) seeded on top of a 3-dimensional fibrin matrix, hMVECs stimulated with fibroblast growth factor-2 (FGF-2) or vascular endothelial growth...

Concentration changes during venous occlusion of proteins with affinity for extracellular matrix in insulin-dependent diabetes mellitus A sign of vascular damage in patients with diabetic nephropathy?

Objective: To investigate protein concentration changes during venous occlusion of proteins with reported affinity for extracellular matrix (plasminogen activator inhibitor type 1, antithrombin III, fibronectin and von Willebrand factor) in comparison with proteins with no reported affinity (albumin, tissue-type plasminogen activator,...

Age-related decrease in proteoglycan synthesis of human articular chondrocytes: The role of nonenzymatic glycation

Objective. To examine the effect of nonenzymatic glycation of cartilage extracellular matrix on the synthetic activity of chondrocytes. Methods. The proteoglycan-synthesis rate (35SO42- incorporation) and levels of advanced nonenzymatic glycation (determined by high-performance liquid chromatography measurement of pentosidine) were evaluated in...

Effect of steroid hormones and retinoids on the formation of capillary-like tubular structures of human microvascular endothelial cells in fibrin matrices is related to urokinase expression

Angiogenesis, the formation of new capillary blood vessels, is a feature of a variety of pathological processes. To study the effects of a specific group of hormones (all ligands of the steroid/retinoid/thyroid hormone receptor superfamily) on the angiogenic process in humans, we have used a model system in which human microvascular endothelial...

Plasma clearance of urokinase-type plasminogen activator

Mechanical properties of the collagen network in human articular cartilage as measured by osmotic stress technique

We have used an isotropic osmotic stress technique to assess the swelling pressures of human articular cartilage over a wide range of hydrations in order to determine from these measurements, for the first time, the tensile stress in the collagen network, P(c), as a function of hydration. Osmotic stress was applied by means of calibrated...

Matrix degradation by chondrocytes cultured in alginate: IL-1β induces proteoglycan degradation and proMMP synthesis but does not result in collagen degradation

Objective: To determine the role of interleukin-1β (IL-1β) in the degradation of proteoglycans and collagen by articular chondrocytes. Design: Chondrocytes were cultured in alginate beads for 2 weeks to produce extracellular matrix, followed by the addition of IL-1β for 1 or 2 days. Breakdown of extracellular matrix (with and without activation...

Synthesis of collagen by bovine chondrocytes cultured in alginate; posttranslational modifications and cell-matrix interaction

The extracellular matrix synthesized by articular chondrocytes cultured in alginate beads was investigated. Collagen levels increased sigmoidally with time and remained constant after 2 weeks of culture. The presence of cartilage-specific type II collagen was confirmed immunohistochemically. Predominantly type H collagen was present in the...

Modified proenzymes as artificial substrates for proteolytic enzymes: Colorimetric assay of bacterial collagenase and matrix metalloproteinase activity using modified pro-urokinase

We describe a new principle for assessment of the activity of proteolytic enzymes of all classes and show the application of this principle for the quantitative assay of bacterial collagenase and human matrix metalloproteinases (MMPs). Central to this new principle is the presence of a proenzyme that can be activated into an active enzyme by a...

Investigation of the association of the CRTM and CRTL1 genes with radiographically evident osteoarthritis in subjects from the Rotterdam study

Objective. To investigate whether radiographically evident osteoarthritis (ROA) in 55-65-year-old men and women is associated with specific alleles or genotypes of the cartilage matrix protein (CRTM) and cartilage link protein (CRTL1) genes. Methods. Cases were selected from a population-based study on the presence of ROA of the knee or hip....

Regulation of plasminogen activation, matrix metalloproteinases and urokinase-type plasminogen activator-mediated extracellular matrix degradation in human osteosarcoma cell line MG63 by interleukin-1 alpha

Plasmin-mediated extracellular proteolysis has been implicated in the degradation of bone in normal and pathological conditions. Normal and malignant osteoblasts can produce both tissue-type plasminogen activator (t- PA) and urokinase-type plasminogen activator (u-PA). We have used the osteosarcoma cell line MG63 to address the question of...

Regulation of matrix metalloproteinase expression in human vein and microvascular endothelial cells: Effects of tumour necrosis factor α, interleukin 1 and phorbol ester

Matrix metalloproteinases (MMPs) play a role in tissue remodelling and angiogenesis. We have investigated the expression and regulation of MMP-1 (interstitial collagenase), MMP-2 (gelatinase A), MMP-3 (stromelysin 1), MMP-7 (matrilysin), MMP-9 (gelatinase B) and their inhibitors TIMP-1 and TIMP-2 in human umbilical vein, femoral vein and...