Proteinase inhibitors in the kidney and its tumours

The proteinase inhibitors alpha-1-antitrypsin and alpha-1-antichymotrypsin are found in a variety of tissues including the kidney. We have used the immunoperoxidase technique to study the distribution of these glycoproteins in 10 fetal and five adult kidneys and in 44 renal tumours. Proteinase inhibitors were found in fetal kidneys in the cells of the metanephric blastema, primitive mesenchyme and in proximal tubules. They were found in proximal tubules of adult kidneys. These substances were also found in the mesenchyme of nephroblastomas and in the tumour cells of clear cell, oncocytic and sarcomatoid variants of renal cell carcinoma. These observations are significant in the understanding of the patterns of differentiation of which renal cell carcinoma is capable.     

HISTOLOGICAL AND ULTRASTRUCTURAL STUDIES OF NEPHROBLASTOMA IN RATS INDUCED TRANS-PLACENTALLY BY ETHYLNITROSOUREA

Histologic and ultrastructural features of nephroblastomas in Sprague-Dawley rats induced by a single transplacental injection of ethylnitrosourea (ENU) on the 15-16th day of gestation are described and their significance is discussed with respect to the histogenesis of the tumors. Many renal tumors were observed, in addition to predominant occurrence of tumors of the nervous system. Forty-two of 142 offsprings survived over 100 days developed renal tumors, of which 37 rats had nephroblastomas, three rats had cortical adenomas, and one rat had a cystadenoma. The nephroblastomas were found in 35 rats unilaterally and in two rats bilaterally. Most of these tumors had various amounts of hyalinized stroma. In the kidneys with nephroblastomas, isolated, small foci of renal blastema were also occasionally noted. Electron microscopy revealed that nephroblastomas consisted of two types of cells, namely, epithelial and mesenchymal cells. The epithelial cells showed cellular differentiation of varying degree; they are freely lying in the stroma, forming well differentiated tubules or immature tubule-like structures and solid cell nests. Most of the undifferentiated cells observed around the tubular structures and cell nests are demonstrated to have epithelial features. These observations seem to support the concept that nephroblastoma is originated from meta-nephric blastema.     

KIT expression in fetal, normal adult, and neoplastic renal tissues

BACKGROUND: KIT is a transmembrane tyrosine kinase receptor, expressed in high amounts in various normal cells. In addition, c-kit mutation or activation is a major pathogenetic event in certain tumours (such as gastrointestinal stromal tumours). There are only limited data in the literature on the expression of KIT in normal and neoplastic renal tissues. AIMS: To investigate KIT expression in normal and neoplastic renal tissues. METHODS: KIT expression was evaluated by means of immunohistochemistry in paraffin wax embedded sections from 67 tissue samples. RESULTS: Eight of eight fetal kidneys, and 10 of 10 normal adult kidneys revealed cytoplasmic staining of renal tubules. The three cases of renal dysplasia studied expressed KIT in their normal and aberrant tubules. Two of 13 conventional renal cell carcinomas (RCCs), two of seven papillary type RCCs, four of seven chromophobe type RCCs, none of six nephroblastomas, seven of seven oncocytomas, two of two mesoblastic nephromas, and two of four angiomyolipomas were positive. CONCLUSION: KIT is expressed in normal fetal and adult renal tubules, and in a subset of renal tumours. The expression of KIT in these renal tumours may prove to have diagnostic relevance and/or therapeutic implications.     

Inguinal nephroblastoma

Summary A case of an extrarenal nephroblastoma is reported which was located in the inguinal region. In the surrounding fat tissue normal ectopic glomerular and tubular structures and two more nephroblastomas were found. Therefore and because of negative clinical investigations in regarding of a renal malignant tumour the inguinal mass was thought to be the primary tumour and not a metastasis. This conclusion is important for the diagnosis and therapy.Chirurgische Abteilung des Städtischen Krankenhaus Kemperhof, D-5400 Koblenz, Federal Republic of Germany     

The human renal lymphatics under normal and pathological conditions

AIMS: The renal lymphatics have not been fully documented in humans. The aim of this study was to clarify the morphology of the human renal lymphatic system under normal and pathological conditions by immunohistochemistry using anti-D2-40 antibody. METHODS AND RESULTS: Normal and pathological renal tissues obtained at autopsy as well as nephrectomy specimens with renal cell carcinoma (RCC) were used. Thin sections were immunostained with antibodies against D2-40 and CD31. In normal kidney, D2-40+ lymphatics were abundant in the interstitium around the interlobar and arcuate arteries/veins but sporadic in those around the glomeruli or between the tubules in the cortex. A few lymphatics contained erythrocytes in their lumina. Lymphatics were seldom present in the medulla. In RCC cases, lymphatics were evident at the tumour margin, whereas CD31+ capillaries were abundant throughout the tumour and lymphatics were increased in the fibrous interstitium around the tumour. Lymphatic invasion by RCC cells was also detectable. D2-40+ lymphatics were evident in other pathological conditions and end-stage kidney had a denser lymphatic distribution than normal kidney. CONCLUSIONS: Lymphatics are abundant around the arteries/veins and are also present in the renal cortex and medulla. D2-40 immunostaining is helpful for investigating the pathophysiological role of renal lymphatics.     

Distribution of cytokeratins,vimentin and desmoplakins in normal renal tissue,renal cell carcinomas and oncocytoma as revealed by immunofluorescence microscopy

Summary Forty-two renal cell carcinomas, one oncocytoma and normal renal tissue were studied for the presence of cytokeratins and vimentin. The investigations were performed by immunofluorescence microscopy applying a panel of mono- and polyclonal antibodies to intermediate filament proteins. In all tumours except chromophobic renal cell carcinoma (CRCC) and oncocytoma a co-expression of cytokeratins and vimentin could be shown. The intermediate filament expression was often, however, very heterogeneous particularly with respect to the distribution of cytokeratins and vimentin, to the clonality of the antibodies used and to the tumour areas studied. The latter could be impressively demonstrated by examining a whole tumour. In CRCC and oncocytoma all tumour cells expressed cytokeratins and, in addition, single tumour cells also expressed vimentin. In normal renal tissue we could show vimentin-positive epithelia of proximal and distal tubules, which is reported for the first time.     

Immunohistochemical study of porcine nephroblastoma

Nephroblastoma, a relatively common renal neoplasm of young swine, represents the animal counterpart of Wilms' tumour of children. Five porcine nephroblastomas were examined histologically, and immunohistochemically with antibodies against vimentin (VIM), cytokeratins (CKs), smooth-muscle actin, Factor VIII, and laminin. Histologically all showed the three components typical of this tumour: mesenchymal blastema, epithelium (tubuli, and glomeruloid bodies) and stroma. The only antibody recognizing mesenchymal cells was VIM. One-third of tubular structures were positive for VIM. All of the tubules were positive for CK19, two-thirds expressed CK AE1/AE3, and only one-third expressed CKs 8-18. Small round tubuli, located in the stromal septa, were positive for CK7 (ureteric branches). Stromal cells expressed both VIM and actin, demonstrating myofibroblastic differentiation. The kidney originates from mesenchymal blastema, which changes to epithelium, losing VIM and acquiring CK expression. In the adult mammalian kidney, CK 19 is expressed only by the parietal epithelium of Bowman's capsule and the distal tubules. Nevertheless, CK19 is also considered a "transient" CK, expressed by different kinds of epithelia during differentiation. CK 19 was also detected in several undifferentiated neoplasms. This finding, together with the co-expression of VIM detected in some tubules, demonstrates the embryonic origin of nephroblastoma.     

Cellular antigens in nephroblastoma: identification with monoclonal antibodies which recognize hemopoietic cells

The correlation between expression of differentiation antigens and morphogenesis was examined in 11 human nephroblastomas using monoclonal antibodies which recognize both hemopoietic and renal cells. Analysis of frozen tissue sections by indirect immunofluorescence revealed that blastema cells and some tubules were recognized by BA-1 and OKB2, which identify unstimulated B cells and granulocytes. Stroma, some tubules, and focal blastema were recognized by BA-2, which identifies a 24-kDa antigen on leukemic cells and platelets. Mature epithelium in glomerular bodies was identified by C3bR and J5, which recognize CR1 and the common acute lymphoblastic leukemia antigen, respectively. Tissue sections from a clear cell sarcoma and a mesoblastic nephroma were notably reactive only with BA-2. These observations demonstrate that the relationship between antigen expression and morphology in nephroblastomas is similar to that observed in fetal kidney and suggest that expression of these cell surface antigens may have a role in morphogenesis.     

The clinical assessment of proliferation and growth in human tumours: evaluation of methods and applications as prognostic variables

Most cases of nephroblastoma have high plasma levels of prorenin which is biologically inactive. Plasma prorenin levels fall to normal following nephrectomy. In order to ascertain whether renin synthesis occurs in nephroblastomas we decided to search for renin-specific mRNA using a cDNA probe and Northern blot analyses on total RNA purified from snap-frozen human tumour tissue obtained at nephrectomy. We demonstrated renin-specific mRNA in 5/11 (45 per cent) nephroblastomas. It was 1.6 Kb in length, similar to the mRNA detected in normal kidney tissue and in kidneys with renal artery stenosis. In one of the cases of nephroblastoma, in which we could detect no normal renin mRNA at 1.6 Kb, the cDNA probe hybridized with a higher molecular weight mRNA 3 Kb in length. We conclude that some nephroblastomas synthesize renin.     

The distribution of cytokeratin antigens in the kidney and in renal tumours

The distribution of cytokeratin antigens during embryogenesis of the kidney and in 57 renal tumours has been studied using immunocytochemical techniques. A polyclonal antiserum to epidermal prekeratins and the monoclonal antibodies CAM 5.2 and PKK1 have been used to identify cytokeratins of different molecular weights. The ureteric bud-derived structures expressed large molecular weight cytokeratins. The tubular component of the kidney expressed cytokeratins detected by CAM 5.2 and PKK1. During glomerular development there was transient expression of low molecular weight cytokeratins by the visceral glomerular epithelium but in the adult kidney only the parietal epithelium expressed cytokeratins. Tubules in nephroblastomas contained low molecular weight cytokeratins but the blastema did not. Some ureteric bud-derived structures were identified in six nephroblastomas. Renal carcinomas expressed low molecular weight cytokeratins. Four collecting duct carcinomas were studied; these all expressed the large molecular weight cytokeratins found in collecting duct epithelium. These results indicate that the cytokeratin phenotype of renal tumours is unchanged from that of the normal epithelial cells.     

Study of childhood renal tumours using antisera to fibronectin, laminin, and epithelial membrane antigen.

Using a peroxidase-antiperoxidase staining procedure, formalin fixed paraffin embedded sections of fetal and normal kidney; benign (mesoblastic nephroma); and malignant tumours (Wilms' tumour, clear cell renal carcinoma, rhabdoid renal tumour, and bone metastasising renal tumour of childhood (BMRTC] were examined for their reactivity with antisera to fibronectin, laminin, and epithelial membrane antigen. Mesoblastic nephroma contained fibronectin but no laminin. Most Wilms' tumours lacked both fibronectin and laminin; 50% of rhabdoid renal tumours were positive for fibronectin and laminin--rhabdoid tumours as recognised morphologically may, in fact, be two separate entities. BMRTC and clear cell renal carcinoma lacked both fibronectin and laminin. Epithelial membrane antigen was present in most of the tubular Wilms' tumour but absent in blastemal Wilms' tumours. The presence of epithelial membrane antigen in rhabdoid tumours was surprising, as histologically, this type of tumour shows no sign of epithelial differentiation. Epithelial membrane antigen antiserum stained clear cell renal carcinomas: epithelial membrane antigen is found in the distal and not the proximal tubules of fetal and normal kidneys. Thus an obvious interpretation is that clear cell renal carcinomas originate from distal rather than from proximal tubules, as has always been thought. On the basis of these results and data from other published findings some possible histogenetic origins of childhood renal tumours were proposed.     

Comparative immunohistochemical analysis of developing kidneys, nephroblastomas and related tumors: considerations on their histogenesis

Immunoperoxidase analysis was performed to evaluate the phenotypic expression of eight renal differentiation antigens in five nephroblastomas, one clear cell sarcoma of the kidney (CCSK), one rhabdoid tumor of the kidney (RTK), and four related tumors. A total of 19 fetal and pediatric kidneys, including two 6th-week mesonephric tissues, were comparatively studied. All the specimens were fixed in formalin and embedded in paraffin. Neural cell adhesion molecule (NCAM), a marker of the nephrogenic zone of the developing kidney, was consistently expressed in the epithelial and blastematous components of nephroblastomas of the common type. The epithelial components also commonly expressed NK1 and Leu 7 (CD57), and the findings may reflect that both were positive in immature proximal tubules directly differentiating from the NCAM-positive immature fetal tubuloglomerular buds. In two cases, the epithelial component was immunoreactive for CD10 and WT1 gene product (WT1-GP). Leu M1, epithelial membrane antigen and CA15-3 were only focally expressed in nephroblastomas. Rhabdomyoblasts in the stroma were positive for WT1-GP. CCSK was featured by the expression of NCAM and CD10. In RTK, focal epithelial differentiation was discerned, with focal positivity of WT1-GP and negativity of NCAM. In congenital mesoblastic nephroma, the stromal spindle cells were strongly immunoreactive for WT1-GP, while WT1-GP was not expressed in solitary multilocular cyst of the kidney. Pancortical nephroblastomatosis was featured by the diffuse subcapsular reappearance of immature metanephric tissue. Nephroblastomas and related conditions thus offer an adequate model for studying human nephrogenesis.     

氯化汞中毒对大鼠肾小管酶活性的影响

目的：检测氯化汞中毒对肾小管上皮细胞酶化学的影响,方法：制作氯化汞中毒大鼠模型,以铈盐为捕捉剂,分别用Ogawa法,改良Hansson法和Kobayashi法对5′－核苷酸酶,碳酸酐酶,及Na^ -K^ ATP酶进行细胞化学检测,并对微区元素进行X－射线能谱分析,结果：染毒组上述三种酶活性都有所降低,以近曲小管为著,X－射线能谱图有铈峰,但未见汞峰。结论：汞对大鼠肾近曲小管上皮有明显毒性作用。     

Flow cytometry of DNA in research on kidney tumors

The DNA content was studied in 22 patients (including 10 children) with renal tumours. Renal clear cell carcinomas were mainly diploid (5 of 6 cases); one clear cell and other variants of renal cell carcinoma were aneuploid. There was a correlation between the degree of tumour cell anaplasia and ploidy of renal cell carcinomas: all diploid carcinomas were of I and II degree of anaplasia, aneuploid carcinomas, except one case, were of degree III of anaplasia. 5 out of 9 nephroblastomas were diploid, 4, aneuploid. The distinctive features of nephroblastoma were pronounced proliferative activity of tumour cells and a low DNA index of the aneuploid cell line which in all cases was localized in the vicinity of the diploid region. The remaining tumours (papillary epithelial nephroma, juxtaglomerular cell tumour and malignant schwannoma) were diploid with a relatively low proliferative activity of tumour cells.     

Morphological Changes in the Kidneys of Rats with Postischemic Acute Renal Failure after Intrarenal Administration of Fetal Mesenchymal Stem Cells from Human Bone Marrow

Chronic experiments on outbred albino rats were performed to compare the dynamics of histological signs for postischemic renal injury (90-min thermal ischemia) after intraparenchymal injection of cultured fetal MSC from human bone marrow. Functional indexes of the ischemic kidney were predetermined. In the early period after ischemia (day 4), administration of human bone marrow MSC was followed by the increase in blood flow in the microcirculatory bed and decrease in the degree of alteration in renal tubules. An increase in the area of zones with histological signs for normal function of tubules was accompanied by the improvement of biochemical indexes for renal function. In the delayed period, a protective effect of cell therapy was manifested in the prevention of death of renal tubules. Mild calcification of the necrotic tubular epithelium served as a marker of this process. Human bone marrow MSC were labeled with the fluorescent probe Calcein. These cells migrated from the site of injection, spread in the interstitium, and retained viability for 7 days. During this period, some cells were incorporated into the lumen of renal tubules. Translated from Kletochnye Tekhnologii v Biologii i Meditsine, No. 1, pp. 3-9, 2009     

Widespread distribution in human tissues of an antigenic determinant of granulocytes.

The monoclonal antibodies AGF4 .48 and AGF4 .36 have previously been shown to distinguish human granulocyte lineage cells from other peripheral blood and bone marrow cells. The AGF4 .48 antigen, which is carbohydrate in nature, together with similar antigens described by numerous investigators have been considered specific differentiation antigens of myeloid cells. In immunohistological studies of a wide range of normal tissues, the AGF4 .48 antibody selectively stained cells in several apparently unrelated tissues. These included proximal tubules and descending thin limbs in the kidney, parietal cells in the stomach, a variety of other epithelial cells, astrocytes in the brain, and cells in the anterior pituitary containing adrenocorticotrophic hormone. The AGF4 .36 antibody gave similar results on kidney, stomach and pituitary. These findings emphasise the importance of assessing the binding of monoclonal antibodies, which appear unique in their reactivity with blood cells, to non-haemopoietic tissues before assigning specificity to reagents. The distribution of cells expressing the AGF4 .48 and AGF4 .36 antigen correlates with the occurrence of the 3-fucosyl-N-acetyllactosamine carbohydrate structure in various secreted glycoproteins.     

The tumour suppressor gene CEACAM1 is completely but reversibly downregulated in renal cell carcinoma

CEACAM1 acts as a tumour suppressor in various epithelial tumours. On the other hand, de novo expression of CEACAM1 is strongly associated with reduced disease-free survival of melanoma and non-small cell lung carcinoma patients. Since effector functions of natural killer and T cells are inhibited by homophilic CEACAM1 interaction, immune escape could be responsible for the poor prognosis of these patients. Here, we describe CEACAM1 expression in normal kidney, renal adenomas and renal cell carcinomas (RCC) using a novel antibody generated by genetic immunization. In normal kidney, CEACAM1 was found in epithelial cells of proximal tubules and in endothelial cells. In contrast, tumour cells of 30 clear cell, three chromophobic, and two chromophilic RCCs were completely devoid of CEACAM1. Renal adenomas also lacked CEACAM1 expression. Similarly, RCC cell lines CaKi1, CaKi2, A498, and RCC26 exhibited no or low-level CEACAM1 expression. However, CEACAM1 expression was transiently induced in A498 cells upon contact with allogeneic CD8+ T cells, mediated at least in part by interferon-gamma. Furthermore, the majority of tumour-infiltrating T and NK cells expressed CEACAM1 upon stimulation. Thus, transient expression of the tumour suppressor CEACAM1 by tumour cells and subsequent homophilic interaction with CEACAM1 on tumour-infiltrating lymphocytes could represent a novel immune escape mechanism in RCC.     

Clear-cell papillary renal cell carcinoma: 24 cases of a distinct low-grade renal tumour and a comparative genomic hybridization array study of seven cases

Adam J, Couturier J, Molinié V, Vieillefond A & Sibony M
(2011) Histopathology 58, 1064–1071
Clear‐cell papillary renal cell carcinoma: 24 cases of a distinct low‐grade renal tumour and a comparative genomic hybridization array study of seven cases Aims: To report clinicopathological and genomic characteristics of (ccpRCC), a rare, recently characterized renal tumour entity. Methods and results: Twenty‐four renal tumours identified as ccpRCC were collected. Data from comparative genomic hybridization on microarrays (array‐CGH) were obtained for seven of these. Most tumours (58%) occurred in the absence of renal disease. Mean patient age was 58.1 years. Tumours were small (mean size: 2.4 cm) and classified as pT1. Histological characteristics consisted of tubules and papillae lined by a single layer of small clear cells harbouring low‐grade nuclei (Fuhrman grades 1 or 2). Architectural variations, with compact areas (41% of cases) and a micro‐ or macrocystic pattern (67% of cases) were observed frequently. Immunostaining demonstrated diffuse, strong expression of cytokeratin 7 and vimentin, whereas CD10, racemase, RCC antigen, translocation factor E3, TFE3 and translocation factor EB were consistently negative. In seven tumours, array‐CGH detected no chromosomal imbalances. Conclusions: Clear‐cell papillary renal cell carcinoma (ccpRCC) were differentiated from other renal neoplasms by a specific constellation of histopathological and immunohistochemical features, without characteristic genomic imbalances. Clinical, histopathological and genomic data suggested that these tumours have a low potential for malignancy.     

3～20周人胚和胎儿肾小体的组织发生

应用光、电镜对3～20周22例人胚和胎儿肾小体的组织发生进行了观察.受精后第25天胚肾已有肾小体发生.随着胚龄的增长,肾小体的发生数目增多,肾小体的形成方式是:胚肾内先形成许多厚壁小管,在一部分厚壁小管的诱导下,另一部分厚壁小管的一侧壁呈帽状增厚,分化形成造血干细胞、毛细血管内皮及肾小囊脏层,对侧壁形成肾小囊壁层.即厚壁小管的双侧壁形成肾小体.