Electron microscopy of endothelial cells in culture: IV. Surface replicas

Summary Few techniques exist for applying the resolving power of the transmission electron microscope to examination of the surface plasma membrane of any cell type. In this paper methods are described for replicating the true outer surface of endothelial cells in culture and for preparing the replicas for examination in a transmission electron microscope.     

Phagocytosis and virulence of different strains of Porphyromonas gingivalis

Abstract – In this study 17 strains of Porphyromonas gingivalis , both reference and clinical isolates, were investigated for their in vitro interaction with human polymorphonuclear leukocytes, hydrophobicity, density, and virulence in a mouse model. The results of the phagocytosis, hydrophobicity, and density experiments showed that P. gingivalis strains could be divided into two distinct groups. One group of strains were readily attached and phagocytosed when exposed to the leukocytes. These bacteria were hydrophobic and had a higher buoyant density than the other group, which were poorly phagocytosed, had a low buoyant density, and were hydrophilic. This latter group also exhibited an extracellular meshwork resembling a glycocalyx when examined by electron microscopy. There were also significant differences between strains in the mouse pathogenicity model. Two strains caused an invasive, spreading infection compared with the other 15 strains which produced small, localized abscesses. There was no clear correlation between the results of the phagocytosis assay and the virulence of the bacteria when injected subcutaneously in mice. Resistance to phagocytosis may be important for survival of these bacteria, but it does not in itself imply the ability to cause damage to the host.     

血管内皮细胞糖萼与心血管疾病

内皮细胞糖萼是覆盖于内皮细胞表面多种活性成分组成的绒毛状细胞结构。内皮细胞糖萼可调控血管通透性,介导剪切力诱导的一氧化氮释放,通过抑制凝血及细胞粘附发挥一系列血管保护作用。而糖萼的降解可能与众多心血管疾病有关。该文就内皮细胞糖萼与心血管疾病的关系作一综述。     

Circulating syndecans during critical illness

Circulating syndecans are proposed to be markers of glycocalyx degradation and previous investigations have found higher plasma levels of syndecan‐1 among patients with different pathological conditions. We wanted to investigate if levels of other syndecans (‐2,‐3 and ‐4) are altered during critical illness and compare the levels to syndecan‐1. In 137 consecutive intensive care unit (ICU) patients with sepsis, cardiac arrest, gastrointestinal bleeding, intoxication or trauma, plasma levels of syndecan‐1, ‐2, ‐3 and ‐4 were measured using ELISA. Syndecan‐1 and syndecan‐3 levels were similar among the different ICU patient groups but higher than controls. No differences in plasma levels of syndecan‐2 or syndecan‐4 were found neither among the different ICU patient groups nor compared to controls. All syndecans showed an association with mortality and the levels of syndecan‐1 and ‐3 and correlated with each other. The results indicate that syndecan release is triggered by the physiological stress of critical illness in general and involves several subtypes such as syndecan‐1 and syndecan‐3.     

糖萼的作用及其在脓毒症中的研究进展

糖萼(glycocalyx)作为内皮细胞腔内侧的多糖结构,主要由蛋白聚糖、氨基葡聚糖(glycosaminoglycans,GAGs)、膜糖蛋白及血浆蛋白组成.糖萼对维持内皮细胞的通透性、形态及结构、血管内微环境有着重要作用,参与包括脓毒症在内多种疾病的生理病理过程.而在脓毒症时,各种炎症因子的作用损伤糖萼的完整性,从而导致糖萼的功能障碍.     

Actions of gluco-oligosaccharide against Staphylococcus aureus

Heavy colonization of atopic dermatitis (AD) with Staphylococcus aureus is well documented. The purpose of the present study is to examine the actions of gluco-oligosaccharide (G-OS) against S. aureus for the control of AD skin lesions infected with S. aureus. The colony counts of S. aureus cells in 0.5% sodium chloride solution supplemented with 5% G-OS (pH 4.8) were about 10-fold lower than those in 0.5% sodium chloride solution (pH 6.6; control) after incubation for 24 hours. The colony counts of S. aureus cells attached on the coverslips (pre-treatment with 1% and 5% G-OS/PBS and following treatment with plasma) were about 10-fold lower than those on the coverslips (pre-treatment with PBS and following treatment with plasma; control) in PBS after incubation for 24 hours. The materials (sugars, probably glycocalyx) that stained positively for fluorescein-isothiocyanate (FITC) -concanavalin A and were consistent with the presence of S. aureus cells were reduced when S. aureus cells attached to the coverslips treated with 5% GC-OS. In conclusion, C-OS is a promising agent that can be applied topically in a cream to clear adherent S. aureus cells from skin lesions of AD in order to prevent its exacerbation. Further, 5% C-OS can inhibit glycocalyx production by S. aureus cells and consequently have some suppressive effect on the colonization of S. aureus on the horny cells of AD lesions.     

Endothelial glycocalyx in health and kidney disease: Rising star or false Dawn?

The endothelial glycocalyx is a layer comprised of proteins and carbohydrates on the luminal surface of vascular endothelial cells, thought to have an important role in the health and function of the endothelium. Disrupted by various pathophysiological conditions and linked with clinical outcomes, it is increasingly recognized as an early indicator of endothelial injury and a potential marker of vascular injury. In this review, we discuss current methods of assessment (including novel optical approaches), evidence for its use as a marker of vascular disease and its potential role in relation to microalbuminuria and glomerular endothelial dysfunction. Therapeutic strategies for restoration of the glycocalyx following injury are also explored.