糖基化终末产物对大鼠肾系膜细胞纤溶酶原激活物抑制物-1表达韵影响

目的：观察糖基化终末产物（AGEs）对大鼠肾系膜细胞纤溶酶原激活物抑制物-1（PAI-1）表达的影响及其与细胞外基质（ECM）成分含量的关系。方法：体外培养正常大鼠肾系膜细胞，分别用糖化牛血清白蛋白（AGEs）及未经糖化的牛血清白蛋白（BSA）处理，以常规培养的肾系膜细胞作为对照，检测不同时间、不同浓度AGEs对纤维连接蛋白（FN）、Ⅳ型胶原、PAI-1表达的影响。MTT法检测AGEs对系膜细胞增殖的作用，ELISA测定条件培养基中FN、Ⅳ型胶原及PAI-1蛋白含量，逆转录聚合酶链式反应（RT—PCR）检测系膜细胞PAI-1 mRNA的表达。结果：与相应浓度的BSA比较，AGEs（0—200mg／L）对系膜细胞增殖无明显影响，但可不同程度地刺激系膜细胞FN、Ⅳ型胶原、PAI-1蛋白的产生。RT—PCR检测显示，给予AGEs（100mg／L）的系膜细胞PAI-1 mRNA的表达明显增加（P〈0．01）。结论：AGEs促进系膜细胞PAI—1的表达，提示AGEs通过上调PAI-1的表达而减少细胞外基质降解，可能是糖尿病肾病细胞外基质积聚的原因之一。     

Relative weight of glucose, insulin and parathyroid hormone in the urinary loss of phosphate by chronically diabetic rats

This report deals with the relationships between glucose (G) and insulin on the tubular transport of phosphate (P) in chronically diabetic rats with high plasma levels of parathyroid hormone (PTH). Alloxan-induced diabetes leads to phosphorus depletion of the soft tissues. This phenomenon appears associated with weight loss and negative P balances caused by the increased urinary P excretion. Administration of 2 IU of insulin/100 g body weight (bw) to diabetic rats normalized their P balance and body weight. The effect of parathyroid function on the P metabolism of diabetic rats was investigated with balance experiments. Diabetic rats, intact or thyroparathyroidectomized (TPTX), have a greater urinary excretion of P than their controls. However, in control rats, the ratio intact:TPTX for urinary P is 1.0:0.76, showing the antiphosphaturic effect of parathyroid ablation. For diabetic animals, on the other hand, the ratio is 1.0:1.44. The simultaneous deficit of insulin and PTH thus quadruples the urinary P loss, instead of compensating for each other. The contribution of insulin deficit and hyperglycemia to the defect in tubular reabsorption (TRP) was investigated with clearance experiments (done on anesthetized, perfused rats). Five experimental groups were used: Controls (C), diabetics (D), controls+glucose (C+G), diabetics+insulin (D+I) and diabetics+insulin+glucose (D+I+G). All experimental groups showed a linear relationship between the TRP of P and G. The regression equation for C is significantly different (F=40.1, P<0.001) from that of D animals. The slope value measure the number of μmoles of P per μmol of G reabsorbed. For C and D rats, the ratio P:G approximates 1:4 and 1:20, respectively. The increase in P:G ratios represents the competition between both substrates for tubular resorption. Glycemias up to 11 mM (C and D+I) exist concurrent with the P:G ratio 1:4. Glycemias above 25 mM (D, C+G and D+I+G) produce a P:G ratio of 1:20. Fractional excretion of P (FEP) increased significantly in untreated, chronically diabetic rats (0.47± 0.12 vs controls=0.05±0.01, P<0.001). After a single intramuscular injection of insulin, the FEP decreased as a function of insulin levels. To normalize the FEP of diabetic rats in short-term experiments, insulin had to be administered in doses that produce plasma insulin levels 25 times greater than normal. The general information afforded by the present experiments shows that in untreated, chronically diabetic rats, insulin deficit plays an indirect role. The absence of PTH enhances the effect of hyperglycemia. The latter and the concurrent tubular overload of glucose are the cause of hyperphosphaturia in these animals. Received: 10 September 1996 / Accepted in revised form: 18 April 1997     

抗中性粒细胞胞浆抗体在肾小球疾病中的检测及临床意义

目的:检测各种肾小球疾病患者血清中抗中性粒细胞胞浆抗体(ANCA)并探讨其临床意义。方法:应用间接免疫荧光法(IIF)检测20例正常人及131例各种肾小球疾病患者血清中ANCA。结果:131例患者中有11例ANCA阳性性(阳性率为8.4％),且均为P-ANCA阳性,而20例正常对照组无1例阳性(P<0.05)。ANCA阳性中以新月体性肾炎、狼疮性肾炎、紫癜性肾炎的阳性率较高,分别为67％、25％、16.7％。新月体性肾炎与IgA肾病等原发性肾小球疾病组比较有显著性差异(P<0.05)。结论:ANCA在各种肾小球疾病中并不少见,尤其是新月体性肾炎、狼疮性肾炎、紫癜性肾炎的阳性率较高,推测ANCA可能在这些疾病的发病机理中起了一定的作用。     

Heparin modulates proliferation and proteoglycan biosynthesis in murine mesangial cells: molecular clues for its activity in nephropathy

Glycosaminoglycan administration has favourable effects on morphologicaland functional renal abnormalities in different models. Thepossibility that exogenous glycosaminoglycans modulate glomerularmatrix synthesis was explored in both primary and SV40-MES13murine mesangial cell cultures. On both cell types, both low-molecular-weightheparin and different glycosaminoglycans showed dose-dependentinhibition of proliferation and increase of ³⁵SO^2–₄ uptake.After 36 h the cell compartment contained a spectrum of ³⁵S-moleculesof less than 200 kDa; under heparin treatment, the two main³⁵SO^2–₄ components (high and medium MW) increased by 16and 37% respectively. Susceptibility to glycosidases revealedthat heparin promotes the expression of heparan sulphate andincreases that of chondroitin sulphate. Moreover, heparin modifiesthe expression of decorin and bigly-can, involved in adhesionand fibrillogenesis, while not affecting perlecan. The extracellularmatrix modulation in renal cells, for which the sulphation typeand ratio of heparin are crucial, may thus explain the beneficialrenal effects of heparin.     

肾病患儿免疫细胞对肾小球上皮细胞合成基质的影响

目的为了明确免疫细胞对肾小球上皮细胞（ｇｌｏｍｅｒｕｌａｒｅｐｉｔｈｅｌｉａｌｃｅｌＧＥＣ）合成功能的直接作用。方法应用肾小球细胞体外培养，同位素掺入及放射免疫技术，以总胶原，层粘连蛋白，Ⅲ型前胶原及Ⅳ型胶原的合成为观察指标，动态研究了不同病理类型原发性肾病综合征（ＩＮＳ）患儿外周血单个核细胞（ｐｅｒｉｐｈｅｒａｌｂｌｏｏｄｍｏｎｏｎｕｃｌｅａｒｃｅｌＰＢＭＣ）对ＧＥＣ生物功能的影响。结果（１）肾病极期未经激素治疗组（未治组）ＰＢＭＣ上清明显促进了ＧＥＣ合成层粘连蛋白；（２）未治ＰＢＭＣ上清抑制了ＧＥＣ合成总胶原；（３）未治组ＰＢＭＣ上清促进了Ⅲ型前胶原的合成，而对Ⅳ型胶原的合成无明显影响；（４）肾病患儿ＰＢＭＣ的上述作用与是否足量激素治疗有关，而与尿蛋白能否阴转、肾组织病理类型、肾病临床类型等无直线相关关系。结论原发性肾病患儿循环免疫细胞可影响ＧＥＣ合成细胞外基质的功能。免疫细胞的这种活性可被激素治疗改变。     

Renal hemodynamics and renal O2 uptake during hypoxia in the anesthetized rabbit

Summary The effects of hypoxic hypoxia on renal hemodynamics and metabolism have been studied in anaesthetized mechanically ventilated rabbits. Acute hypoxia (F₁O₂=0.10,PaO₂=35 torr) induces at constant mean arterial pressure a 45% decrease in RBF, GFR, and whereas free water clearance increases. These alterations were still apparent 50 min after resuming normal arterial oxygenation. In order to assess the role of the stimulation of catecholamine release in these observations, two other sets of experiments were performed: 1) the animals were ventilated with the same hypoxic gas mixture but after adrenergic blockade (phentolamine: 0.2 mg·kg·min^–1 i.v.), 2) hypoxia was induced by ventilating the animals with CO (F_ICO=0.002) at constantPaO₂. Increase in renal vascular resistance and reduction of renal O₂ uptake were still observed. This indicates that adrenergic stimulation cannot fully explain the renal vasoconstriction encountered in hypoxia. The role of a local vasoactive factor, especially that of the renin angiotensin system is discussed. The apparent O₂ cost of Na reabsorption was not greatly modified by any type of hypoxia and the Na:O₂ ratio remained close to the value observed in normoxic animals. This indicates that the kidney may adapt to hypoxia by reducing its O₂ demand keeping unaltered its tubular function and basal O₂ needs.     

肿瘤坏死因子与肾小球系膜细胞的关系

目的研究肾小球系膜细胞的肿瘤坏死因子的自分泌功能,肿瘤坏死因子对肾小球系膜细胞作用的机制。方法利用体外培养的人和大鼠的肾小球系膜细胞,通过逆转录－多聚酶链反应、原位杂交和免疫组化方法,探讨它们之间的关系。结果肾小球系膜细胞既可产生肿瘤坏死因子,又有肿瘤坏死因子受体。结论肾小球系膜细胞是肿瘤坏死因子作用的靶细胞,肿瘤坏死因子通过旁分泌和自分泌两种途径作用于肾小球系膜细胞。     

Role of glomerular prostanoid in control of glomerular filtration rate in rats

Summary It is generally accepted that the main action of glomerular prostanoids (GPs) on glomerular filtration rate (GFR) is to modulate the activity of different vasoconstrictors, specially in states of renal hypoperfusion. However it was also suggested that GPs may directly affect GFR. The present study was focused on this last hypothesis, in different experimental models, in rats.In adriamycin induced acute renal failure, the transient decrease of GFR is associated with higher levels of thromboxane B₂. Later on, when GFR returns to normal, vasodilator prostaglandins synthesis was also increased.In captopril induced renal failure in Na depleted rats (where GPs synthesis remained normal), stimulation of PGE₂ and PGI₂ production by K and NaCl was associated with a significant improvement of GFR. Furthermore, the increase in GFR induce by NaCl was prevented by inhibition of prostaglandin synthesis.Infusion of atrial natriuretic peptide in euvolemic rats induce a marked elevation both of GFR and PGE₂ synthesis. It was abolished by previous administration of prostaglandin synthesis inhibitor.In conclusion, glomerular prostanoids may influence GFR, either directly, or as mediator or modulator of other vasoactive hormones.Abbreviations GPs glomerular prostanoids - PG prostaglandin - TX thromboxane - ANP atrial natriuretic peptide - GFR glomerular filtration rate - PE polyethylene Nachtrag zu den Hauptreferaten des 19. Kongresses der Gesellschaft für Nephrologie in Göttingen (Klin Wochenschr 66/18)     

Interaction of transforming growth factor β1 with human glomerular epithelial cells in culture: opposite effects on synthesis of matrix proteins and on urokinase plasminogen activator

The effect of transforming growth factor- (TGF-) was analyzed on the synthesis of fibronectin, collagen type IV, and urokinase plasminogen activator in human glomerular epithelial cells in culture. An increase in the abundance of specific mRNA was found for collagen type IV and fibronectin. Fibronectin protein synthesis was also increased in TGF- treated cells; most of the de novo synthesized fibronectin was found as an unsoluble protein associated with extracellular matrix. In the same cells the amount of plasminogen activator mRNA was found leading also to a decreased surface expression of urokinase plasminogen activator. The data support the concept that by upregulating matrix protein synthesis and downregulating the plasminogen activator system, TGF- favors the development of sclerosis.Abbreviations FN Fibronectin - GEC Glomerular epithelial cells - TGF- Transforming growth factor - uPA Urokinase-type plasminogen activator