Effect of lipoid nephrosis cytokine on glomerular sulfated compounds and albuminuria

Supernatants from peripheral blood mononuclear cells cultures of 30 idiopathic, minimal lesion, nephrotic syndrome (IMLNS) patients in relapse and the same patients in remission were fractionated by gel filtration chromatography. Fractions eluting with carbonic anhydrase (29 kilodaltons) were infused for 5 days at the rate of 10 l/h into the left renal artery of Wistar rats using an Alzet osmotic pump. On the last day of infusion, rats were injected with³⁵sulfate (1.0 mCi/200 g) intraperitoneally and killed after 8 h. Glomeruli were isolated and glomerular basement membrane (GBM) obtained. There was a significant increase in³⁵sulfate uptake by GBM of the infused kidney (302±92 cpm/mg dry glomerular weight, mean±SEM) compared with the uptake seen in the contralateral kidney (157±36,P<0.01) when the fraction from IMLNS patients in relapse was infused. No significant differences in³⁵sulfate incorporation were seen between infused kidney (166±41) and contralateral kidney (172±64) when the same fraction from patients in remission was administered. A significant increase in albuminuria was seen on the last day of infusion (14.2±1.0 mg/24 h, mean±SEM) when supernatant factor from IMLNS patients in relapse was used. No significant differences in urinary albumin excretion prior to and after infusion were seen when the same fraction from IMLNS patients in remission was administered. The in vivo infusion of supernatant factor from IMLNS patients in relapse increased the³⁵sulfate uptake by GBM and augmented albuminuria, suggesting that the factor may have pathogenic significance in the proteinuria of IMLNS.     

Anti-interleukin 8 antibody abolishes effects of lipoid nephrosis cytokine

Supernatant factor from peripheral blood mononuclear cell (PBMC) cultures of idiopathic minimal lesion nephrotic syndrome (IMLNS) patients in relapse induces in vivo albuminuria and increases ³⁵sulfate uptake by glomerular basement membrane (GBM) in rats. The purpose of this study was to evaluate the effect of anti-interleukin 8 (IL8) neutralizing antibody on the effects induced by the supernatant factor. Supernatant factor collected from six cultures of PBMC from IMLNS patients in relapse were combined and aliquoted into two samples. Anti-IL8 neutralizing antibody (750 ng) was added to one. Supernatant factor or supernatant factor and anti-IL8 antibody were infused for 5 days into the left renal artery of Wistar rats using an osmotic pump. On the last day of infusion, rats were injected with ³⁵sulfate (1.0 mCi/200 g) intraperitoneally and killed after 8 h. Glomeruli were isolated and GBM obtained. There was a significant increase in ³⁵sulfate uptake of the infused kidney (169±52 cpm/mg dry glomerular weight, mean ± SEM) compared with the uptake seen in the contralateral kidney (116±41, P <0.05) when the supernatant factor was infused alone. No significant differences in ³⁵sulfate incorporation were seen between infused kidney (173±5) and contralateral kidney (190±49) when supernatant factor and anti-IL8 antibody were administered. A significant increase in albuminuria was seen on the last day of infusion (0.43±0.11 albumin/creatinine ratio, mean ± SEM) compared with the ratio prior to infusion of the supernatant factor alone (0.18±0.03, P <0.05). No significant differences in urinary albumin/creatinine ratios prior to and on the 5th day of infusion were seen when the supernatant factor was administered with anti-IL8 antibody. Supernatant factor effects were abolished by the addition of anti-IL8 neutralizing antibody, suggesting that the described effects are mediated by IL8. Received February 24, 1997; received in revised form December 16, 1997; accepted December 17, 1997     

Unusual histological findings in a child with idiopathic nephrotic syndrome

We report a 2-year-old child with corticosteroid-resistant nephrotic syndrome whose renal biopsy revealed light microscopically normal glomeruli but highly unusual finger-like projections and arches of the glomerular basement membrane. To our knowledge, the association between nephrotic syndrome and this patient’s rare ultrastuctural lesion has not been previously documented in the literature. It is not certain whether this basement membrane is pathogenic or a striking but coincidental developmental anomaly.     

Alport's syndrome: specificity and pathogenesis of glomerular basement membrane alterations

In Alport's syndrome (AS) thinning and splitting of the glomerular basement membrane (GBM) are assumed to be characteristic ultrastructural alterations. Both lesions are, however, non-specific because they can occur in other glomerulopathies. In addition, splitting may be found in non-glomerular structures. It should be emphasized that the characteristic lesion in AS is a result of the widespread combination of thin and split GBM in the same biopsy specimen. In our opinion the basic lesion is the thin GBM, which is characterized by a lamina densa (measuring 50–150 nm in thickness) which may begin to split as a result of focal detachment of podocyte pedicles (spacing) and repeated subepithelial deposition of new lamina densa layers. Splitting thus appears to be a secondary lesion. Thinning of GBM may represent a persistent embryonal status of the lamina densa and may thus be the result of a development defect. This assumption is supported by the findings of fetal-like glomeruli and small capillary loops in AS.     

Hereditary disorders of the glomerular basement membrane

Increased knowledge of the biochemical composition of the glomerular basement membrane (GBM) and the introduction of molecular genetics has shed new light on the hereditary disorders of the GBM. In this review three disorders are highlighted. About 85% of the cases reported as Alport syndrome are transmitted as the X-linked form and are due to mutations of the COl4A5 chain localized at Xq22. The autosomal recessive form can be explained by mutations in the COl4A3 and COl4A4 gene. Anti-GBM nephritis leading to loss of the renal allograft in about 1% – 5% of transplanted Alport patients can be the tragic consequence of this disorder. Some patients with familial benign hematuria have an abnormality of COl4A4. The nail-patella syndrome is a rare autosomal dominant disorder defined by the association of nail dysplasia, bone abnormalities, and frequently renal disease. The gene is localized in region 9q34.1, COl5A1 is not involved. The Finnish type is the best known of the different forms of congenital nephrotic syndrome. The gene has been mapped to the long arm of chromosome 19. Diffuse mesangial sclerosis occurs in the isolated form and as part of the Denys Drash syndrome. Disturbances of the WT1 function in the epithelial cells can have a role in the renal abnormalities of the Denys Drash syndrome. Received May 7, 1996; accepted May 21, 1996     

成年人肾小球基底膜厚度及基底膜变薄标准研究

目的 了解成年人肾小球基底膜（GBM）厚度及拟建议薄基底膜肾病（TBMN）的GBM弥漫变薄的标准。 方法 选取肾癌根治性切除患者29例,分析性别、年龄、尿常规、Scr以及既往史、家族史等临床资料。选取远离病灶的肾皮质组织,进行光镜、免疫荧光及透射电镜检查,并进行GBM厚度测量和Ⅳ型胶原α3、α5链免疫荧光检查。 结果 29例中,男15例、女14例,年龄（55.9±14.9）岁（20~80岁）,所有病例均无肾脏病家族史。肾组织GBM厚度为（363.6±46.8） nm。GBM厚度与性别相关,男性为（384.0±41.7） nm,女性为（335.0±39.2） nm,差异有统计学意义（P = 0.008）。建议以均数减去两倍标准差作为GBM变薄的标准,即GBM厚度＜270 nm。 结论 成年人肾组织的GBM厚度为（363.6±46.8） nm。GBM厚度和性别相关,男性GBM厚度大于女性,差异有统计学意义。TBMN的GBM弥漫变薄的诊断标准建议为GBM厚度＜270 nm,也建议今后制定TBMN标准中应考虑男女的差异。     

Urinary excretion of glomerular basement membrane-related peptides in children with renal disorders

Urinary excretion of glomerular basement membrane (GBM)-related peptides was analysed in 72 patients with a variety of renal diseases by immunoblotting using polyclonal antibodies against either collagenase or pepsin digests of human GBM. The specificity of the antibodies was verified by elution of antibodies bound to urinary GBM-related peptides on nitrocellulose blots and demonstration of reactivity of the eluted antibodies with the respective GBM digests. Furthermore, six mice immunized with urinary GBM-related peptides all developed focal linear deposits of mouse IgG along their GBM, linear and mesangial deposits of C3 in the glomeruli and serum antibodies reactive with human GBM. Monoclonal antibodies against urinary GBM-related peptides of one of the mice reacted with different peptides of the non-collagenous and collagenous domains of type IV collagen, the major structural protein of GBM. In the majority of the 75 patients' urines tested, excretion of GBM-related peptides with molecular weights of 33, 50, 80 and 150 kilodaltons (kD) was detectable. Patients with a diminished glomerular filtration rate (GFR) demonstrated excretion of the 33 kD peptide more frequently (91%) and never of the 80 kD peptide as compared with patients with normal GFR (33 kD [42%] 80 kD [87%]). The pattern of urinary GBM-related peptides was not specific for the underlying renal disease as in Alport's syndrome.     

Charged compounds of the glomerular filter and their role in normal and disordered permselectivity

Infusion into rats of the polycation hexadimethrine (HDM) leads to onset of massive proteinuria, which recovers when the infusion is stopped. Several lines of evidence indicate that the proteinuria results from binding of HDM to polyanions of the glomerular filter, with neutralization of shielding of their charges. To determine the mechanism of this proteinuria, we measured the glomerular sieving coefficients of anionic and neutral forms of albumin and IgG in control and proteinuric rats. Surprisingly, these studies revealed a marked defect in size dependence, but not in charge dependence, of glomerular permselectivity in hexadimethrine-treated animals, indicating that binding of HDM induces a structural change in the glomerular filter. In vitro studies of binding of tritiated HDM and cationized ferritin to glomerular basement membrane (GBM) indicate that the binding is not dependent on proteoglycans such as heparan sulfate, nor on sialoproteins such as podocalyxin, but is dependent on charged carboxyl groups of GBM.     

Glomerular deposits and hypoalbuminemia in acute post-streptococcal glomerulonephritis

In a search for correlations between glomerular morphology and clinical manifestations in acute post-streptococcal glomerulonephritis, data for 40 biopsied patients were reviewed. A major correlation was observed between severe hypoalbuminemia and the absence of deposits on the paramesangial portion of the glomerular basement membrane. Subepithelial deposits were present on both the capillary loop and paramesangial segments of the basement membrane in 29 patients, whereas in 11 the deposits were present only on the capillary loop. Patients with paramesangial segments devoid of deposits had a mean (±1 SD) nadir serum albumin level of 1.90 (±0.40) g/dl, whereas the mean nadir level in those with deposits in both locations was 2.83 (±0.64) g/dl (P<0.001). Also significant was the difference in paramesangial deposit scores in patients with nadir serum albumin levels ≤2.5 g/dl versus those with levels >2.5 g/dl. The amount of subepithelial deposit on the capillary loop was not significantly different in the two groups, and no correlation was found between loop deposits and serum albumin levels. Except for greater edema and significantly less-frequent gross hematuria in those with absent paramesangial deposits, clinical and laboratory findings for the two groups did not differ. Received September 18, 1997; received in revised form December 8, 1997; accepted January 27, 1998     

Clomerular and urinary heparan sulphate in congenital nephrotic syndrome

Studies using cationic probes have suggested that a reduction in glomerular anionic sites, composed principally of the glycosaminoglycan heparan sulphate, is responsible for the abnormal glomerular permeability in the congenital nephrotic syndrome (CNS). We therefore analysed the glycosaminoglycan content of the glomerular basement membrane (GBM) from an infant who died of CNS and from an infant who died of unrelated causes. We also measured the urinary excretion of glycosaminoglycans in children with nephrotic syndrome, both congenital and acquired, and in healthy children. Heparan sulphate constituted 59% of the glycosaminoglycan content of the GBM in the normal infant, the other principal glycosaminoglycan being chondroitin sulphate. In the GBM from the infant with CNS the heparan sulphate was greatly reduced, constituting only 3% of total glycosaminoglycans. The urinary excretion of heparan sulphate was significantly increased in CNS (expressed both in relation to creatinine and to chondroitin sulphate) compared with normal children and to those with acquired nephrotic syndrome. Diminished GBM content of heparan sulphate may be responsible for the abnormal glomerular permeability in CNS and may be a consequence of defective incorporation of heparan sulphate into the GBM with subsequent loss into the urine.     

Effect of cyclosporin A on glomerular filtration rate in children with minimal change nephrotic syndrome

Cyclosporin A (CyA) is now commonly used in the management of children with steroid-dependent nephrotic syndrome. In order to assess nephrotoxicity related to CyA therapy, we measured glomerular filtration rate (GFR) on 123 occasions in 24 children with minimal change nephrotic syndrome receiving CyA. GFR was estimated from the plasma clearance of⁵¹chromium-EDTA every 3 months during CyA therapy of up to 27 months duration. There was a significant reduction in GFR after 3 months of CyA therapy [118±33 (SD) to 93±24 ml/min per 1.73 m²] but no further fall thereafter, although the reduction in GFR was sustained for the duration of CyA therapy. This reduction in GFR appeared to be reversible upon cessation of CyA, but careful monitoring of renal function is necessary in such patients to prevent the development of longer term nephrotoxic sequelae.     

Lymphocyte subpopulations,interleukin-2 and interleukin-2 receptor expression in childhood nephrotic syndrome

Abnormal T lymphocyte function and reduced interleukin-2 (IL-2) production have been implicated in the pathogenesis of the nephrotic syndrome (NS). We investigated: (1) lymphocyte subpopulations and expression of IL-2 receptor (IL-2R) on T cells using two-colour flow cytometry, (2) serum IL-2 and (3) the soluble component of IL-2R (sIL-2R) in serum, using enzyme-linked immunosorbent assay, in 38 children with NS. All children, except those in remission, had marked proteinuria. They were divided into groups according to renal pathology: (1) steroid-sensitive NS (SSNS) not receiving prednisolone therapy, (2) SSNS on prednisolone, (3) focal segmental glomerulosclerosis (FSGS), (4) SSNS in remission and not receiving prednisolone therapy, (5) congenital NS (CNS). Results were compared with 26 age-matched controls. Total T lymphocytes (CD3) were reduced in groups 1 and 2; CD4 count was reduced in groups 1–4; CD8 count increased in groups 2 and 3; CD8 and CD19 (B lymphocytes) were significantly reduced in group 5. Increased IL-2R expression (CD25) on CD4 lymphocytes was noted in groups 1, 2 and 3 implying activation of these cells. In patients with SSNS, increased serum sIL-2R was recorded during relapse (1,273±497 U/l vs. 913±401 U/l in remission,P<0.005) but free serum IL-2 was not detectable at any stage. The specific alterations in lymphocyte subpopulations in SSNS and FSGS would imply an involvement of the immune system distinct from that in CNS.     

Morphometric study of glomerular basement membrane and proximal tubular basement membrane in adult thin basement membrane disease

Background. Thin basement membrane disease (TBMD) is a benign hereditary glomerulopathy with a diffuse attenuation of glomerular basement membrane (GBM). Whether the development of renal basement membranes other than GBM is normal in TBMD has not yet been resolved. Methods. We performed a morphometric study to measure the thickness of GBM and proximal tubular basement membrane (P-TBM) in 44 adult patients with TBMD and in 10 adult diseased controls confirmed to have minor glomerular abnormalities. Results. There was a significant difference between the patients with TBMD and the diseased controls in the thickness of the GBM; however, there was no significant difference between the two groups in the thickness of the P-TBM. In the patients with TBMD, the thickness of the GBM was unchanged with age, but the thickness of the P-TBM increased with age, as did that in the diseased controls. Conclusion. Our morphometric study clarified that the development of P-TBM was normal in the patients with TBMD. Received: October 7, 1998 / Accepted: May 27, 1999     

Interleukin-8 alters glomerular heparan sulfate glycosaminoglycan chain size and charge in rats

We have previously shown that the in vivo infusion of interleukin-8 (IL8) in rats causes albuminuria and an increased catabolism of the heparan sulfate (HS) glycosaminoglycans (GAG). The purpose of this study was to characterize further the in vivo effect of IL8 on rat HSGAG. The left renal artery of male rats was continuously infused with IL8 (750 ng/ml, 4 rats) or 1% bovine serum albumin (3 rats) using an osmotic pump. On the 5th day of infusion, ³⁵sulfate (1.0 mCi/100 g) was given intraperitoneally and the rat was killed 8 h later. Glomerular HSGAG was isolated and its size and charge was determined by liquid chromatography. The HSGAG ³⁵sulfate uptake was higher in IL8-treated rats than controls (387±138 vs. 246±15 cpm/1,000 glomeruli, mean ± SD, P<0.05). No differences in HSGAG size were observed between IL8-treated and control animals. However, after ion exchange chromatography, there was a shift to the left in the elution profile of IL8-treated rats, demonstrating the presence of chains with decreased negative charge. IL8 infusion into rats results in a decreased total negative charge of the HSGAG. Because IL8 has been found in the serum of some patients with minimal lesion nephrotic syndrome, this finding may explain, at least in part, the reported reduced glomerular charge barrier observed in these patients. Received: 10 November 1998 / Revised: 8 June 1999 / Accepted: 8 June 1999     

Abnormal glomerular basement membrane in idiopathic multicentric osteolysis

The primary cause of nephropathy in idiopathic multicentric osteolysis is as yet unknown. We report a young girl with idiopathic multicentric osteolysis and nephropathy. An abnormal glomerular basement membrane was the only abnormality found in a renal biopsy taken 2 years before the development of end-stage renal failure. We believe that this biopsy finding represents or is related to the unknown primary lesion causing nephropathy in idiopathic multicentric osteolysis.     

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。     

A histopathological study on the prognosis of childhood IgA nephropathy and glomerular basement membrane lesions

Seventy-three patients with IgA nephropathy (IgAGN), under the age of 15 years at the time of the discovery of the disease, were investigated with respect to glomerular basement membrane (GBM) lesions. Irregular attenuation or widening of GBM, especially on the epithelial side, was observed in 28 cases (38%). These two changes are referred to aslysis of GBM and were considered to be the primary and specific changes among the GBM lesions in IgAGN. GBM thickening with layering of lamina densa was found in 37 of 73 cases (51%), but this change has been observed in other types of glomerular diseases. GBM lesions similar to those seen in IgAGN were also observed in Henoch-Schönlein purpura nephritis (HSPN) and poststreptococcal acute glomerulonephritis (PSAGN). Lysis of GBM was observed only in IgAGN, HSPN and PSAGN. Subepithelial and intramembranous deposits appeared to have an important role in the development of these GBM lesions. The presence of GBM lesions was correlated with a high incidence of cellular crescents but not with other clinical or light microscopic findings. The presence of these GBM lesions in IgAGN does not have a significant effect on the prognosis, at least in childhood. The affected GBM seemed to recover without leaving any significant residual damage in most cases. In the long-term prognosis of the disease non-immunological factors, such as ageing or hypertension, seem to be important.     

Characterisation and Specificity of Glomerular Basement Membrane Antigens Identified by Sera of Patients with Anti-GBM Nephritis

The sera of 21 patients positive for antibodies against GBMin indirect immunofluorescence tests were examined by immunoblotting.We demonstrated antibodies against 50, 48, 43 and 29 kD molecularweight peptides in 20 of 21 sera using collagenase-digestedGBM, in 19 of 21 using trypsin-digested GBM, and in.10 of 21using elastase-digested GBM. Although the spectrum of molecularweights of the antigenic proteins was similar in all three digests,they differed with respect to preservation of antigenicity uponreduction with mercaptoethanol. Many of the sera of patientsand controls reacted with proteins unrelated to GBM, e.g. albuminand prealbumin. Furthermore, some control sera reacted withone single peptide of the above-mentioned specific GBM peptides.Our results suggest that the highly purified 29 kD peptide ofthe collagenase digest or the 50 kD peptide of the trypsin digestprovide the best antigens to develop a screening test for antibodiesagainst GBM. However, serum antibodies against these antigenswill not be absolutely specific for anti-GBM antibody-mediatednephritis, as shown by the immunoblot experiments.     

Alport syndrome with neurofibromatosis type-I: a case report

We report a 9-year-old boy with repeated fractures of the tibia from age 6 months and microscopic hematuria from age 2 years. His maternal family has a history of nephritis and his paternal family has neurofibromatosis type-I (NF-I). The boy’s renal biopsy revealed an irregular attenuation and splitting of the glomerular basement membrane. The skin biopsy was stained with monoclonal antibody against the α5 chain of type IV collagen; the epidermal basement membrane was negative in the boy and segmentally positive in the boy’s mother. We conclude that the patient inherited Alport syndrome from his mother and NF-I from his father. We postulate this was a chance association and that this case does not suggest any relationship between the two diseases. Received August 21, 1996; received in revised form and accepted March 20, 1997     

丙泊酚对大鼠肾缺血-再灌注期血清白细胞介素-8的影响

目的观察丙泊酚对大鼠肾缺血-再灌注期血清白细胞介素-8(IL-8)的合成和释放的影响,并探讨其肾保护机制。方法选用12~14周雄性大鼠75只,随机分为三组,每组25只,以无创动脉夹夹闭双侧肾蒂60min制备急性肾缺血-再灌注模型。A组为肾缺血-再灌注组,B组为丙泊酚处理组,C组为假手术组。各组设立五个时间观察点:缺血前10min(T0),缺血60min(T1),再灌注1h(T2)、3h(T3)、6h(T4),每个时间点5只大鼠。C组:肾脏缺血60min,缺血前5min从股静脉注射丙泊酚20mg/kg,继之经微量泵持续输入丙泊酚(0·5mg/ml)50mg·kg-1·h-1,持续60min;A、B组以等容生理盐水取代丙泊酚,但A组不夹闭双侧肾蒂,术中保持大鼠呼吸、循环稳定。各组大鼠存活至预定时间后再次麻醉取标本,测定血浆丙二醛(MDA)、超氧化物歧化酶(SOD)、血清IL-8,同时用光学显微镜观察肾组织形态学改变及肾小管损伤情况。结果血浆MDA在C组T1~T4时无明显变化,同A组相似,较B组相应时点显著降低,而B组T1~T4时较T0时及A组各时点显著升高;SOD则呈相反变化;C组T1~T3时血清IL-8无明显变化,仅在T4时较T0时和A组有显著升高,而B组在T1~T4时分别增加1·73、2·50、2·76、2·89倍,同C组和A组相比有显著性差异;光镜下观察发现B组肾小管上皮细胞变性、坏死,细胞脱落,肾小管管腔变窄,肾间质水肿、充血伴炎性细胞浸润明显;而C组以肾小管肿涨为主,个别呈坏死样改变,肾间质水肿、充血、炎性细胞浸润不明显。结论丙泊酚除了有抗氧作用外,还能有效地抑制血清IL-8合成和释放,这可能是丙泊酚减轻肾缺血-再灌注损伤的机制之一。