Renal Tubular Dysgenesis in Twin-Twin Transfusion Syndrome

In twin-twin transfusion syndrome (TTTS), the disparity in circulation is reflected in discordant fetal growth, urine output, and amniotic fluid accumulation. The effect of uneven shunting of the growth factor and nutrient-rich vasculature on development and differentiation of the kidney has not been well studied. We analyzed renal tubular growth and differentiation in 25 fetal autopsies with TTTS (13 donors and 12 recipients, including 9 sibling pairs) between 18 and 33 weeks gestation. Immunohistochemical markers for fumarylacetoacetate hydrolase (FAH), Leu-M1, and Lotus tetragonolobus (LTA) were used to identify proximal convoluted tubules, and epithelial membrane antigen (EMA) was used to demonstrate distal convoluted and collecting tubules. FAH appeared to be more specific and reliable than either Leu-M1 or LTA in the identification of proximal tubules. Donors tended to demonstrate a paucity of proximal tubules with crowding of glomeruli characteristic of renal tubular dysgenesis (RTD). The degree of dysgenesis was greater in later gestations and associated with more severe growth restriction. Donors in TTTS are at risk for the development of RTD. Several authors suggest ischemia as the underlying cause of “acquired” RTD. However, in this setting there is no evidence of cell death or necrosis, and we suggest that hypoperfusion leading to decreased glomerular filtration is the underlying etiology, with the severity of RTD related to the degree of shunting. Received November 12, 1997; accepted February 12, 1998.     

Renal Tubular Dysgenesis: A Description of Early Renal Maldevelopment in Siblings

A family is described in which three siblings, born after pregnancies complicated by oligohydramnios, developed renal abnormalities. In the first infant, of 38 weeks gestation, histologic changes were nearly identical to those found in renal tubular dysgenesis (RTD), a recently identified disorder characterized by the absence of recognizable renal proximal tubules. Additional findings include bilateral renal vein thrombosis and marked calvarial bone hypoplasia. The other two gestations were 20 and 22 weeks long. Renal histology in these cases showed nonspecific abnormalities with focal tubular dilatation, decreased tubule formation, and increased interstitial connective tissue. Clearly recognizable proximal tubules were present, though decreased in number. The latter two gestations described herein are the earliest examined in a family with RTD and the renal abnormalities may represent early changes seen in this disorder.     

Renal Proximal Tubular Dysgenesis Associated with Severe Neonatal Hemosiderotic Liver Disease

We report the necropsy findings for three infants with the unusual combination of proximal renal tubular dysgenesis and severe congenital liver disease with excessive iron in several organs resembling neonatal hemochromatosis. Two of the infants were caucasian siblings and one was an Australian aborigine. One died in utero at 35 weeks of gestation and two died at 7 days. The liveborn infants presented with anuria and liver failure. The livers all showed marked loss of hepatocytes and replacement by pseudotubules in the collapsed lobules. The liveborn infants also showed giant cell transformation ofhepatocytes, small regenerative nodules, cholestasis, and normal bile ducts. Absence of proximal renal convolutions was confirmed by epithelial membrane antigen positivity in nearly all tubules. In each family there was another sibling with congenital liver disease, fatal in one case, but no renal tubular dysgenesis. No infection or metabolic disease was uncovered in any of our patients, and the cause of the hepatocyte destruction was not determined. The combination in three infants of two rare congenital diseases could be genetic or acquired in utero from the same etiological agent. Alternatively, the absence of proximal convolutions could be secondary to hypoperfusion, perhaps because of shock due to extensive necrosis of hepatocytes.     

Neonatal Hemochromatosis, Renal Tubular Dysgenesis, and Hypocalvaria in a Neonate

We report a neonate with neonatal hemochromatosis (NH), renal tubular dysgenesis (RTD), and hypocalvaria. NH is a fatal condition of the newborn, characterized by severe idiopathic liver failure of intrauterine onset and siderosis, intra- and extrahepatic, with sparing of the reticuloendothelial system. RTD is characterized by short, abnormally developed cortical tubules that lack proximal tubule differentiation. Although both NH and RTD have been reported as entities with a genetic component, similar findings can be secondary to in utero insults. Hypocalvaria has been reported in association with fetal hypoxia including that secondary to angiotensin converting enzyme inhibitors. This 38-week-old infant died at 8.5 h. The small nodular liver weighed 44 g. Grossly, the kidneys were normal. Hypocalvaria was present. Microscopically, the hepatic parenchyma was distorted by fibrous tracts, proliferation of bile ducts, and abundant iron deposition in hepatocytes. Extrahepatic siderosis in the pancreas, myocardium, and other organs was consistent with NH. Proximal convoluted tubules were not seen on routine stains and markers for proximal tubules were negative. Previous reports have linked NH with RTD and RTD with hypocalvaria. This infant had all three of these rare conditions, which have been hypothesized or shown to be due to genetic factors, hypoxia, or drugs. The etiology in this case is unknown. Received May 20, 1997; accepted August 15, 1997.     

Renal Tubular Dysgenesis in an Hydropic Fetus with Trisomy 21: a Case Report with Literature Review

Renal tubular dysgenesis (RTD) is a rare form of noncystic renal disease characterized by paucity or absence of proximal renal tubules. Always lethal in the perinatal period, it has been associated with Potter sequence and with other congenital malformations. An autosomal recessive inheritance has been suggested. We present a case of renal tubular dysgenesis associated with fetal hydrops and trisomy 21, with a review of relevant literature.     

Familial Renal Tubular Dysgenesis: A Disorder Not Isolated to Proximal Convoluted Tubules

The autopsy findings of a newborn with renal tubular dysgenesis, born to first cousins of Moslim Arob descent, are described. Hypocalvaria and hyperflexible joints were noted in addition to the renal lesion. A microdissection study demonstrated marked shortening of all the nephron segments from the glomeruli to the collecting tubules, rather than an isolated abnormality of the proximal convoluted tubules.     

Congenital Hypernephronic Nephromegaly with Tubular Dysgenesis: A Distinctive Inherited Renal Anomaly

This paper describes a distinct, apparently inherited renal disorder we call congenital hypernephronic nephromegaly with tubular dysgenesis. The disorder is characterized by oligohydramnios, the Potter phenotype, and enlarged nonfunctional kidneys. Light microscopy demonstrates increased numbers of glomeruli, undifferentiated tubules, and interstitial fibrosis. Microdissection reveals short, immature nephrons that lack proximal convolutions, and abnormal vascularization of the glomerulus. Morphomet-ric analysis demonstrates increased glomerular mass, primarily in the region of the corticomedullary junction, increased interstitial mass, and decreased tuOular mass. The parameters that define this anomaly are presented, and the possible mechanisms of pathogenesis are discussed in relation to pathologic observations and current concepts concerning renal embryogenesis and differentiation. The recurrence of this anomaly in the male children of a consanguineous couple suggests an X-linked recessive mode of inheritance, although an autosomal-recessive mode of inheritance cannot be ruled out. This condition indicates that not all cases of the Potter phenotype can be considered to be sporadic.     

Proximal Renal Tubular Acidosis in a Child with Type 1 Glycogen Storage Disease

ABSTRACT. A 6 1/2-year-old Japanese girl with type 1 glycogen storage disease developed a profound metabolic acidosis refractory to bicarbonate renal tubular acidosis and hyperphosphaturia. There was no evidence of distal tubular dysfunction.     

Proximal Renal Tubular Acidosis Associated with Glycogen Storage Disease, Type 9

ABSTRACT. A 21/2-year-old Japanese boy with glycogen storage disease, type 9, developed proximal renal tubular acidosis (RTA). The RTA significantly improved in response to cornstarch therapy, implying a direct causal relationship between subtle metabolic derangements in glycogen storage disease, type 9, and proximal RTA.     

Renal Tubular Acidosis in a Case of Shwachman's Syndrome

ABSTRACT. We describe metabolic acidosis in a 15-month-old girl with clinical features of Shwachman's syndrome. Renal function tests indicated that the patient had type 1 renal tubular acidosis. Based on our findings and other reports of renal tubular dysfunction in patients with Shwachman's syndrome, we conclude that it is important to look for a possible renal tubular defect in this syndrome.     

Hereditary Tyrosinemia of Chronic Course without Rickets and Renal Tubular Dysfunction

ABSTRACT. Three patients with hereditary tyrosinemia type 1, two brothers and one girl, studied at the age of 5, 12 and 15 years, respectively, had neither generalized hyperaminoaciduria, glucosuria nor clinical symptoms of rickets. Untreated the elder brother had only slightly elevated plasma tyrosine level (141 μmol/l, normal <80), and low excretion of p-hydroxyphenyllactate. He presented with pronounced thrombocytopenia (3 × 10⁹/1). At 13 years of age he contracted hepatocellular carcinoma. The younger brother presented with serum tyrosine of 318 μol/l and thrombocyte count 48 × 10⁹/1. Succinylacetone in urine was elevated in both, 30 and 79 μmol/mmol creatinine, respectively. The female patient was investigated for hepatomegaly in infancy, atypical tyrosinemia being considered, but afterwards developed normally without diet or any other treatment until she contracted hepatoma at the age of 15 years. Her plasma tyrosine level was 600-700 μmol/1, and she excreted large amounts of p-hydroxyphenyllactate. Succinylacetone in urine was low but elevated (8 μmol/mmol creatinine). The fumarylacetoacetase activity in fibroblasts from the brothers and in lymphocytes from the girl was less than 5% and 10% of control levels, respectively. In conclusion, the chronic form of hereditary tyrosinemia may occur without evidence of renal tubular dysfunction.     

Prohibitin1和Prohibitin2在缺氧性肾小管上皮细胞损伤中的表达及作用

目的探讨Prohibitn1(PHB1)、Prohibitin2(PHB2)在缺氧性肾小管上皮细胞(RTEC)损伤中的表达和作用。方法以体外培养的大鼠近端肾小管上皮细胞株(NRK-52E)为对象,NRK-52E细胞置于50 mL.L-1二氧化碳(CO2),37℃培养箱中孵育至80%,传代后随机分为正常组和模型组。正常组细胞继续培养,模型组细胞置于真空罐中,负压吸引器抽尽残余空气,充以配好的缺氧气体(950 mL.L-1氮气和50 mL.L-1CO2)密封建立缺氧性RTEC损伤模型,分别于造模第12、24、36小时采用实时荧光定量PCR检测PHB1、PHB2、转化生长因子-β1(TGF-β1)mRNA表达,Western blot检测PHB1、PHB2蛋白表达。结果 1.与正常组比较,模型组各时间点NRK-52E细胞的PHB1、PHB2蛋白及其mRNA表达均降低(Pa<0.05),缺氧时间越长,表达量越低;NRK-52E细胞的TGF-β1 mRNA表达均增高(Pa<0.05),缺氧时间越长,表达量越高。2.相关性分析:模型组NRK-52E细胞的PHB1、PHB2 mRNA表达与TGF-β1 mRNA表达均呈负相关(r=-0.97、-0.99,Pa<0.05)。结论缺氧所致NRK-52E细胞的PHB1、PHB2蛋白及mRNA表达均降低,缺氧时间越长,表达量越低,NRK-52E细胞损伤越重。PHB1、PHB2可能参与RTEC损伤的发生发展。     

Prohibitin基因转染对肾小管上皮细胞表型转化的影响

目的探讨转染外源性Prohibitin(PHB)基因对体外培养的肾小管上皮细胞株(NRK-52E)表型转化的影响。方法将构建的pcDNA3.1(+)-PHB1、pcDNA3.1(+)-PHB2质粒转染体外培养的NRK-52E细胞作为转染组,以空载体转染NRK-52E细胞为阴性对照组,以正常NRK-52E细胞为空白对照组,分别应用实时荧光定量PCR和Western blot检测转染24 h、48 h、72 h各组NRK-52E细胞PHB1、PHB2及α-平滑肌肌动蛋白(α-SMA)的mRNA及蛋白表达。结果 1.转染24 h、48 h、72 h时转染组NRK-52E细胞的PHB1、PHB2 mRNA及其蛋白表达均较阴性对照组和空白对照组增高(Pa<0.05),且48 h表达量最高,而阴性对照组与空白对照组比较差异无统计学意义。2.转染24 h、48 h、72 h时转染组NRK-52E细胞α-SMA mRNA和蛋白表达均较阴性对照组和空白对照组降低(Pa<0.05),48 h表达量最低,阴性对照组与空白对照组比较差异无统计学意义。3.转染组48 h NRK-52E细胞PHB1、PHB2蛋白表达量与α-SMA蛋白表达量均呈负相关(r=-0.942、-0.869,Pa<0.05)。结论转染外源性PHB基因可以抑制体外培养的NRK-52E细胞的表型转化。     

低钾血症致肾囊性病变2 例报告并文献复习

目的探讨低钾血症导致的获得性肾囊性病变的临床特点和发病机制。方法总结2例以慢性低钾血症为主要表现、伴有肾囊性病变的肾小管疾病患儿的临床资料,并结合文献进行复习。结果 2例患儿均为男性,年龄分别为16岁和14岁,例1原发病为Dent病(1型)、例2为肾小管酸中毒(1型),共同特点为长期低钾血症史,未正规治疗、随访,均合并多发肾脏囊肿,无其他遗传性肾囊性病变的证据,例1合并肾功能异常、例2合并肾钙化。结论长期低钾血症可导致肾囊性病变,早期诊治、治疗和规律随访尤为重要。     

Short-Term Effect of Low and High Protein Intake on Renal Function in Children with Renal Disease

ABSTRACT. The short-term effect of different levels of protein intake on renal function was investigated in 18 children with moderately (51–85 ml/min/1.73 m² BSA) or severely (9–50 ml/min/1.73 m² BSA) reduced glomerular filtration rates (GFR). The GFR and effective renal plasma flow (ERPF), estimated as the clearances of respectively inulin and para-aminohippuric acid during uncontrolled (2-2.5 g/kg bw), low (1.2 g/kg bw for 12 days) and high (3–5 g/kg bw for 24 h) protein intake were determined by a standard clearance method employing continuous infusion and spontaneous voiding. There were no significant differences in GFR or ERPF during uncontrolled and low protein intake. During high protein intake the GFR and ERPF increased significantly in patients with GFRs above 50 ml/min/1.73 m² BSA and ERPFs above 150 ml/min/1.73 m² BSA. It is concluded that these findings might indicate a functional reserve capacity in children with only moderately reduced renal function.     

美国肾脏病基金会制定的有关儿童慢性肾脏疾病的应用指南

儿童慢性肾脏疾病(CKD)严重危害儿童和青少年健康,美国肾脏病基金会近年规范了有关CKD的定义、分期、评估及治疗,并为早期发现儿童CKD提出了推荐方案:1.一次尿尿液的蛋白/Cr比值;2.用血肌酐预测公式如Schwartz公式等评估肾小球滤过率。本文着重介绍这一指南及在应用时应注意的问题。     

促红细胞生成素减轻窒息新生儿血清诱导人肾小管细胞损伤

目的 研究促红细胞生成素（EPO）对新生儿窒息后血清导致人近曲肾小管上皮细胞（HK-2）损伤的保护作用。方法 以HK-2为研究对象，分为对照、窒息和EPO干预组（每组n=8），以200mL／L窒息血清作为攻击因素，观察各组细胞形态、LDH漏出率和细胞存活[四甲基偶氮唑蓝（MTT）法]变化。结果 与对照组比较，窒息组细胞形态发生改变，LDH漏出率增加，细胞存活减少，差异有显著性（P〈0．05）；而与窒息组比较，除EPO 1 IU／mL组外，EPO组细胞形态明显得到改善，LDH漏出率降低，细胞存活增加，差异具有显著性（P〈0．05），且具有剂量依赖性。结论 EPO有减轻窒息后血清所致HK-2细胞损伤作用。     

尿酸上调肾小管上皮细胞还原型烟酰胺腺嘌呤二核苷酸磷酸酶蛋白水平对肾小管上皮细胞凋亡的影响

目的 观察不同水平尿酸对体外培养的肾小管上皮细胞还原型烟酰胺腺嘌呤二核苷酸磷酸(NADPH)及活性氧簇(ROS)的影响,探讨尿酸损害肾小管上皮细胞的可能机制.方法 分离肾小管上皮细胞,将其分为对照组与尿酸干预组(尿酸干预组又分0.1、0.2、0.4、0.8 mmol·L<'1>4个亚组),每组重复6孔;紫外分光光度法测定肾小管上皮细胞内NADPH蛋白水平;光泽精化学发光法测定肾小管上皮细胞内超氧阴离子(O<,2>)生成量;脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(TUNEL)与琼脂糖凝胶电泳法检测肾小管上皮细胞凋亡.结果 24 h后,0.1 mmol·L<'1>尿酸干预组NADPH酶蛋白水平与O<,2>生成量较对照组仅轻微增高,0.2、0.4、0.8 mmol·L<'1>尿酸干预组NADPH酶蛋白水平与O<,2>生成量均较对照组显著增高(P<,a><0.01).对照组细胞均未形成明显的DNA凋亡梯带,0.1、0.2、0.4、0.8 mmol·L<'-1>尿酸干预组均可见明显的DNA凋亡梯带,0.4、0.8 mmol·L<'-1>尿酸干预组DNA凋亡梯带较0.1、0.2 mmol·L<'-1>尿酸干预组更为明显.TUNEL结果显示:对照组,0.1、0.2、0.4、0.8 mmol·L<'-1>尿酸干预组的凋亡率分别为(17.5±1.0)‰、(72.4±12.4)‰、(136.8±13.4)‰、(328.7±32.6)‰、(427.2±51.5)‰,0.1、0.2、0.4、0.8 mmoi·L<'-1>尿酸干预组细胞凋亡率均明显高于对照组(P<,a><0.01),各尿酸干预组之间细胞凋亡率随着尿酸干预浓度的增高而增高;相关分析发现肾小管上皮细胞凋亡率与肾小管上皮细胞内NADPH酶蛋白水平及O<,2>生成量呈显著正相关(r=0.765、0.792,P<,a><0.01).结论 肾小管上皮细胞在持续高尿酸的作用下,可激活细胞内NADPH酶蛋白表达,释放O<,2>,启动氧化应激级联反应,使肾小管上皮细胞持续受损而导致肾小管上皮细胞凋亡增加.     

江西地区肾脏病儿童757例肾活检的病理与临床资料分析

目的 探讨儿童肾脏疾病的病理特点及其与临床表现的关系.方法 回顾性分析2002年2月-2010年6月在江西省儿童医院行肾活检的757例肾病患儿的病理及临床资料.将肾活检组织分别行光镜、免疫荧光、免疫组织化学及电镜检查.肾活检组织均作苏木精-伊红(HE)、过碘酸雪夫反应(PAS)、六胺银(PASM)及Masson染色;免疫荧光检测IgG、IgA、IgM、C3、C4、C1q.有乙型肝炎病毒感染证据者肾组织同时行乙型肝炎表面抗原(HBsAg)、乙型肝炎e抗原(HBeAg)、乙型肝炎核心抗原(HBcAg)免疫组织化学.参照中华医学会肾脏病分会2000年制定的标准进行病理分型,结合临床和病理资料进行统计分析.结果 1.肾活检病例757例中原发性肾小球疾病537例(70.97%),其中肾病综合征265例(49.35%),孤立性血尿99例(18.44%);继发性肾小球疾病211例(27.84%),其中紫癜性肾炎144例(68.25%),乙肝相关性肾炎47例(22.27%);遗传性肾小球疾病9例(1.19%).2.原发性肾小球疾病病理类型最多的是系膜增生性肾小球肾炎277例(51.58%);继发性肾小球疾病中紫癜性肾炎最多,为144例(68.25%),其病理分级以Ⅱb～Ⅲb为主,占79.17%;遗传性肾小球疾病中Alport综合征8例;薄基底膜肾病1例.结论 江西地区儿童肾脏疾病以原发性肾小球疾病为主,病理改变以系膜增生性肾小球肾炎占绝大多数;继发性肾小球疾病中除以紫癜性肾炎为主外,乙肝相关性肾炎并不少见.