Elevated anti-alginate serum titers in patients with acute cholangitis and gallstones imbedded withPseudomonas aeruginosa

Electron microscopy and bacteriological culture revealed viable bacteria covered with a glycocalyx (biofilm) in choledochal stones recovered from two patients with acute cholangitis. On the cut surface of the choledochal stones, the cholesterol stone component was surrounded with a layer of brown pigment stone. In each case, bacterial culture of the choledochal stone recoveredPseudomonas aeruginosa. Since alginate is the main component of the glycocalyx produced byP. aeruginosa, serum IgM, IgG and IgA anti-alginate antibodies were measured in each patient. The present study is the first to demonstrate acute and transient IgM seroconversion to alginate in cases of acute cholangitis. In one case, the elevation of anti-alginate IgM preceded the elevation of anti-alginate IgG. The authors propose that the bacterial glycocalyx may play a significant role in acute cholangitis.     

Diazoxide may protect endothelial glycocalyx integrity during coronary artery bypass grafting

Abstract

Objectives. Plasma hyaluronan and syndecan-1 levels represent shedding of the endothelium glycocalyx during ischemia and edema. Diazoxide, a K_ATP-channel opener, has been shown to decrease myocardial edema during coronary artery bypass grafting (CABG). We evaluated whether Diazoxide exerts an impact on plasma hyaluronan and syndecan-1 levels during CABG. Design. Representative blood samples for hyaluronan and syndecan-1, before, during and after surgery, were obtained in 13 out of 16 patients that had a history of stable coronary artery disease undergoing CABG with or without Diazoxide. Electron microscopy from biopsies procured from the right atrium in 9 patients was performed to confirm ultrastructural differences among patients before and during CABG. Results. Ultrastructural differences were apparent between individual patients already before operation at base line reflecting differences in the severity of myocardial ischemia and edema. A significant decrease of hyaluronan and syndecan-1 values was observed in patients with Diazoxide after surgery (p < 0.04). Significant correlation of Plasma hyaluronan and syndecan-1 levels was observed in patients with Diazoxide but not in controls (p < 0.005, Spearman rank rho). Conclusion. Diazoxide may have an impact on levels of peripheral plasma hyaluronan and syndecan-1 after CABG, suggesting decreased shedding of the endothelial glycocalyx layer.     

Tonic regulation of vascular permeability

Our major theme is that the layered structure of the endothelial barrier requires continuous activation of signalling pathways regulated by sphingosine‐1‐phosphate (S1P) and intracellular cAMP. These pathways modulate the adherens junction, continuity of tight junction strands, and the balance of synthesis and degradation of glycocalyx components. We evaluate recent evidence that baseline permeability is maintained by constant activity of mechanisms involving the small GTPases Rap1 and Rac1. In the basal state, the barrier is compromised when activities of the small GTPases are reduced by low S1P supply or delivery. With inflammatory stimulus, increased permeability can be understood in part as the action of signalling to reduce Rap1 and Rac1 activation. With the hypothesis that microvessel permeability and selectivity under both normal and inflammatory conditions are regulated by mechanisms that are continuously active, it follows that when S1P or intracellular cAMP are elevated at the time of inflammatory stimulus, they can buffer changes induced by inflammatory agents and maintain normal barrier stability. When endothelium is exposed to inflammatory conditions and subsequently exposed to elevated S1P or intracellular cAMP, the same processes restore the functional barrier by first re‐establishing the adherens junction, then modulating tight junctions and glycocalyx. In more extreme inflammatory conditions, loss of the inhibitory actions of Rac1‐dependent mechanisms may promote expression of more inflammatory endothelial phenotypes by contributing to the up‐regulation of RhoA‐dependent contractile mechanisms and the sustained loss of surface glycocalyx allowing access of inflammatory cells to the endothelium.     

Modifying the vessel walls in porcine kidneys during machine perfusion

Background

Endothelial glycocalyx regulates the endothelial function and plays an active role in maintaining vascular homeostasis. During ischema and reperfusion, the glycocalyx is rapidly shed into the blood stream. A Corline heparin conjugate (CHC; Corline systems AB, Uppsala, Sweden) consists of 70 heparin molecules that have the capacity to adhere strongly to biological tissues expressing heparin affinity. We hypothesized that CHC could be used to restore disrupted glycocalyx in vivo in kidneys from brain-dead pigs.

Materials and methods

Brain death was induced in male landrace pigs (n = 6) by inflating a balloon catheter in the epidural space until obtaining negative cerebral perfusion. The recovered kidneys (n = 5 + 5) were perfused by hypothermic machine perfusion using two Lifeport kidney transporters (Organ Recovery Systems, Chicago, IL). CHC (50 mg) (including 25 mg biotinylated CHC) or 50 mg unfractionated heparin (control) was added to the perfusion fluid in the respective machines. In one case, the kidneys were used only for dose escalation of CHC with the same procedure.

Results

CHC was detected by immunofluorescence and confocal microscopy in the inner surface of the vessel walls. The binding of CHC in the kidney was confirmed indirectly by consumption of CHC from the perfusion fluid.

Conclusions

In this first attempt, we show that CHC maybe used to coat the vessel walls of perfused kidneys during hypothermic machine perfusion, an approach that could become useful in restoring endothelial glycocalyx of kidneys recovered from deceased donors to protect vascular endothelium and possibly ameliorate ischemia and reperfusion injuries.     

盐酸多奈哌齐联合脑脉通治疗老年痴呆的作用机制研究

目的探讨盐酸多奈哌齐联合脑脉通治疗老年痴呆的作用机制。方法选择无特定病原体(SPF)级健康雄性SD大鼠50只作为研究对象,随机分为空白组、模型组、盐酸多奈哌齐组、脑脉通组与联合用药组,每组10只。除空白组外,其余各组采用皮下注射D-半乳糖和聚集肽Aβ25~35制备老年痴呆大鼠模型。建模成功后,盐酸多奈哌齐组给予盐酸多奈哌齐0.85 mg/(kg·d)灌胃,脑脉通组给予脑脉通复方制剂1.50 g/(kg·d)灌胃,联合用药组同时给予盐酸多奈哌齐和脑脉通灌胃,空白组和模型组给予生理盐水2.50 mL/(kg·d)灌胃,持续灌胃8周。分别于给药前、给药1周、3周、5周和8周时测定血清糖萼损伤标志物(Syndecan-1、硫酸乙酰肝素)水平。于给药8周后处死各组大鼠,观察各组大鼠脑组织形态,检测脑组织匀浆中白细胞介素(IL)-6、IL-1及肿瘤坏死因子-α(TNF-α)含量和脑源性神经营养因子(BDNF)、神经生长因子(NGF)蛋白表达水平。结果与模型组比较,盐酸多奈哌齐组、脑脉通组和联合用药组脑组织海马神经细胞排列恢复一定的规律性,数量增多。与模型组比较,盐酸多奈哌齐组、脑脉通组与联合用药组炎性因子水平均降低(P<0.05或P<0.01)。与模型组比较,盐酸多奈哌齐组和脑脉通组BDNF、NGF表达水平差异均无统计学意义(P>0.05),联合用药组BDNF、NGF表达水平升高(P<0.01)。与模型组比较,盐酸多奈哌齐组和脑脉通组在灌胃5周时,联合用药组在灌胃3周时,血清Syndecan-1和硫酸乙酰肝素水平降低(P<0.05)。结论盐酸多奈哌齐与脑脉通联合用药对老年痴呆大鼠的改善作用可能是通过保护血管内皮糖萼、抑制炎症反应,进而修复海马神经组织和提高神经营养因子水平实现的。     

汉滩病毒感染诱导血管内皮细胞多糖包被损伤及其机制初步研究

目的 探讨汉滩病毒(hantaan virus,HTNV)感染血管内皮细胞致多糖包被(glycocalyx,GCX)损伤的分子机制.方法 利用HTNV感染人脐静脉血管内皮细胞(human umbilical vein endothelial cells,HUVECs),在感染不同时间段,ELISA检测细胞上清中GCX组...     

搏动灌注对体外循环期间血流剪切力及血管内皮糖萼功能的影响

目的 研究应用搏动灌注对体外循环期间血流剪切力(FSS)及血管内皮糖萼(VEG)功能的影响.方法 选取体外循环下瓣膜置换手术患者40名,随机分为搏动灌注组及平流灌注组,每组患者20名,比较两组患者临床预后指标、FSS、VEG及炎症反应标志物[多配体蛋白聚糖-1(syndecan-1)、硫酸乙酰肝素及趋化因子C-C型配体...     

Quantitation of glycocalyx production in coagulase-negative Staphylococcus

The purpose of this study was to develop sensitive and accurate methods of quantitating bacterial glycocalyx. Coagulase-negative staphylococci were cultured in trypticase soy broth. Quantitation of slime production was evaluated using various methods of fixation and staining. The amount of dye associated with bacterial slime was assessed spectrophotometrically following solubilization of the dye-biofilm complex by 0.2 M NaOH at 85 degrees C for 1 h. Carnoy's solution was optimal for fixation of the slime, and toluidine blue staining was most reproducible. Fifteen strains of Staphylococcus epidermidis showed a gradation in biofilm production ranging from high, medium, to low that was strain stable. Irrespective of the technique used, high, medium, and low producers of bacterial slime remained in the same category and always showed significantly different optical density readings (p less than 0.05). In our experiments, solubilization of a toluidine blue-bacterial biofilm complex was a direct, simple, and efficient method for reproducibily quantitating glycocalyx. This method provides a useful means of rapid quantitation of biofilm production to assess its role in the infection process and in the response to antibiotic therapy.     

Region-Dependent Role of the Mucous/Glycocalyx Layers in Insulin Permeation Across Rat Small Intestinal Membrane

The regional difference in the contribution of the mucous/glycocalyx layers in rat small intestine, as a diffusional or enzymatic barrier, to the absorption of insulin was investigated by in vitro studies. The mucous/glycocalyx layers from the duodenum, the jejunum, and the ileum in rat were successfully removed without damaging membrane integrity, by exposing them to a hyaluronidase solution in situ. In an in vitro transport experiment, the apparent permeability coefficient (P_app) of insulin for the hyaluronidase-pretreated group was significantly increased compared to the PBS-pretreated (control) group in all small intestinal regions, and the P_app of insulin in both PBS- and hyaluronidase-pretreated groups increased in the following order: duodenum < jejunum < ileum. On the other hand, irrespective of small intestinal regions, the P_app of FD-4 and of antipyrine, respectively the passive para- and transcellular permeation marker, exhibited no significant differences between PBS- and hyaluronidase-pretreated group. In addition, a significant amount of insulin was degraded in the mucous/glycocalyx layers compartment removed by hyaluronidase pretreatment, and the degradation activity in the mucous/glycocalyx layers showed regional differences in the following order: duodenum > jejunum > ileum. These findings suggest that, irrespective of small intestinal regions, the mucous/glycocalyx layers contributed to insulin permeation predominantly as an enzymatic barrier, and not as a diffusional barrier. Furthermore, the variation of the enzymatic activities in the mucous/glycocalyx layers and in the brush-border membrane would be one factor that accounts for the regional differences in the transport of insulin.