Effect of selected flavonoids on glycosaminoglycans in human skin fibroblasts

Purpose: Glycosaminoglycans (GAGs) and proteoglycans (PG) in addition to collagen are the main components of extracellular matrix (ECM). They play an important role in intercellular communication and interactions between cells and ECM. The biological changes in ECM that occur during aging are induced by decrease in GAG biosynthesis. The purpose of this study was to evaluate the effect of selected flavonoids isolated from Cirsium palustre (L.) Scop. on GAG content in human skin fibroblasts. Materials and methods: Human skin fibroblasts were treated with eriodictyol 7-O-glucoside (C1), 6-hydroxyluteolin 7-O-glucoside (C2), scutellarein 7-O-glucoside (C3) and pedalitin (C4) at 1, 20 and 40 μM for 24 h. Concentration of GAGs in the medium was assayed using method based on their ability to bind the cationic dye 1,9- dimethylmethylene blue (DMMB). Results: C1, C2 and C4 at concentration of 20 and 40 µM significantly increased content of sulphated GAGs in the medium. In contrast, treatment of cells with compound C3 did not have a statistically significant impact on GAG level. Ascorbic acid used as a positive control at 50 µM showed no effect on GAG concentration and increased their content at 100 µM but to a much lower extent than flavonoids. Conclusion: Flavonoids C1, C2 and C4 showed greater than ascorbic acid stimulatory impact on GAGs in healthy human skin fibroblasts, demonstrating their therapeutic potential in the aging.

Regional Glycosaminoglycan Coverage of Healthy Rabbit Menisci

The meniscus is an important load-bearing structure in the knee, as it provides load distribution and cushioning properties during weight-bearing activities. The compressive modulus and permeability of the meniscus is attributed to the tissue’s glycosaminoglycan (GAG) content, as charged proteoglycan side chains allow for tissue swelling and resistance to compression [1]. The distribution of sulphated GAGs throughout the meniscus has not been thoroughly documented. Although load differs across the knee joint, few researchers have investigated medial/lateral and coronal differences in meniscal architecture and GAG distribution [2, 3]. It is hypothesized that the distribution of positive histological staining for sulfated GAGs will differ across spatial regions of rabbit menisci. Primarily, it is hypothesized that regions of the menisci that likely see higher loading will demonstrate an increase in sulfated GAG-positive staining area.

Electrophoretic and chromatographic patterns of glycosaminoglycans of the umbilical cord vessels and their alteration in EPH-gestosis.

It was found that hyaluronic acid is the most abundant glycosaminoglycan (GAG) both in the umbilical cord arteries and in the umbilical cord veins. Chromatographic and as well as electrophoretic studies demonstrated that EPH-gestosis (Edema-Proteinuria-Hypertension), the most common pathological syndrome occurring in pregnancy, is accompanied by premature replacement of hyaluronic acid by sulphated GAGs in the investigated arteries but not in the veins. Such a replacement is a characteristic feature of the ageing process. One may conclude that EPH-gestosis is associated with a "premature ageing" of the umbilical cord arterial walls. The mechanism and possible role of this phenomenon in pathology are discussed.

Identification of glycosaminoglycans in the chondrocranium of the chick embryo before and at the onset of chondrogenesis

It appears that hyaluronate is associated with cell migration and the chondroitin sulphates with differentiation during morphogenesis of the chick embryo. The aim of this study was to see if such a correlation could be made for chondrocranium morphogenesis. Specifically, the purpose of this study was (1) to determine the proportion of extracellular matrix (ECM) to cell area and total head mesenchymal area during chondrocranium morphogenesis; and (2) to identify the location, types, and relative amounts of glycosaminoglycans (GAG) being synthesized in the presumptive chondrocranium at the onset of chondrogenesis and prior to this time. Morphometric analyses were made on median and parasagittal sections of heads of stage-24 and -33 embryos in order to determine relative contributions of cells and ECM to the total area of head mesenchyme at these stages. Presumptive chondrocrania (heads minus eyes) of these stage embryos were also analysed histochemically and biochemically in order to identify the GAGs present in the ECM. Sections of whole heads were stained with alcian blue at low and high pH as well as digested prior to staining with hyaluronidase (Streptomyces and testicular). Identification of GAGs was done by pulse labelling embryos with [3H]glucosamine, digesting homogenates with hyaluronidase (Streptomyces or testicular), precipitating the undigested GAGs with cetylpyridinium chloride and countingthe dissolved precipitates using scintillation spectrophotometry. The types and relative amounts of GAGs present in the presumptive chondrocranium were determined by comparing the amount of radioactivity in the precipitates of the non-digested GAG with the counts in the precipitates of the predigested GAGs. This study reports that chondrogenesis begins in the presumptive chondrocranium of the chick embryo at stage 33 and that the area of the head mesenchyme increases 60-fold between stages 24 and 33. Little change in cell density and individual cell area as well as in the relative proportion of total area allocated to cells and ECM occurs. GAGs are localized exclusively in the presumptive chondrocranium. These GAGs are restricted to the ventral half of the presumptive chondrocranium. Within this region, the GAGs are further localized to the presumptive facial area, perichordal region, ethmoid, sphenoid and periotic regions. The types of GAG being synthesized in the head mesenchyme of both stage-24 and -33 embryos are hyaluronate, the chondroitins and unidentified sulphated GAGs (dermatan, keratan, heparin and heparan sulphate). At stage 24, hyaluronate, chondroitin and the unidentified sulphated GAGs constitute about 33% each of the GAG being synthesized. At stage 33, the level of hyaluronate synthesis drops to 2%, the chondroitins to 24% and the unidentified sulphated GAGs increase to 74%. There is an 18·5-fold decrease in the percentage of hyaluronate, a 1·5-fold decrease in the amount of chondroitins and a 2·7-fold increase in the percentage of unidentified sulphated GAGs being synthesized as chondrocranium morphogenesis proceeds.

Pattern Of Plasma Beta-Thromboglobulin, Platelet Factor4 And Factor VIII Complex In Monitoring Haemolytic Uremic Syndrome In Children

Seven children, 2-5 years old, with HUS, were investigated sequentially for plasma BTG, PF4/FVIII complex. Plasma BTG is reported both as plasma concentration and as BTG/Platelets/μl ratio. Recent data suggest that BTG and PF4 enhance microangiopathic involvment of HUS, by inhibition of prostacyclin availability from vessel walls (BTG) and by bind ing of sulphated GAGs on the endothelial cells (PF4).High values of FVIII R: Ag/FVIII:C ratio are an index of endothelial damage. Six children were treated with plasma and antiaggregating agents and one child was treated only with antiaggregating agents. A close relationship between FVIII R:Ag/FVIII:C ratio and BTG and PF4 levels was found. These laboratory findings were in agreement with the clinical course: high values of FVIII R:Ag/FVIII:C ratio, of BTG and PF4 levels were found in the acute phase of the disease and normal values during remission. All patients had a favourable course of the disease and have now normal renal function. We think that plasma infusion may normalize the platelets/vesseI wall interaction.