Laura Torri Tarelli

Variability of clinical phenotype in a large Alport family with Gly 1143 Ser change of collagen alpha 5(IV)-chain.

In a large Italian family with adult-onset Alport syndrome, molecular analysis of the COL4A5 gene, which encodes the alpha 5(IV)-chain of glomerular basement membrane collagen, revealed a GGC-->AGC change in exon 38, resulting in substitution of a serine for a glycine in position 1143 of the polypeptide chain, between interruptions 19 and 20 of the triple helical domain. The mutation leads to loss of a restriction site for the enzyme Msp I, and could thus be easily recognized in several female and male relatives. Among relatives of both sexes who carried the same mutation, the clinical phenotype of Alport syndrome was variable as for the onset of renal failure and the presence of associated ear and eye abnormalities.

Renal transplantation from living donor parents in two brothers with Alport syndrome. Can asymptomatic female carriers of the Alport gene be accepted as kidney donors

Renal transplantation from living donor parents was performed in two brothers with end-stage renal failure due to Alport syndrome (AS). Two years later, the patient receiving the kidney graft from the mother, obligate carrier of AS, presented persistent microhematuria and proteinuria with normal renal function. The histological study demonstrated ultrastructural glomerular lesions consistent with AS. The authors conclude that: (1) Alport patients should not be deprived of renal transplantation from living donors, since anti-GBM nephritis is a rare complication; (2) an oligosymptomatic female carrier of the Alport gene may be considered as living renal donor, although a longer follow-up is needed in order to draw definitive conclusions.

Acute Glomerulonephritis in Human Brucellosis

Acute Glomerulonephritis in Human Brucellosis C. Cecilia Doregatti A. Angela Volpi L.T. Laura Torri Tarelli M. Mario Brognoli F. Ferdinando Giordano M. Mietta Meroni G. Giancarlo Orlandini A. Adalberto Sessa Servizio di Nefrologia e Dialisi, Ospedale di Leno, Leno, Italia;Servizio di Nefrologia e Dialisi, Ospedale di Vimercate, Vimercate, Italia; Istituto di Anatomia Umana Normale, Università degli Studi, Milano, Milano, Italia

Two Brothers With Idiopathic Membranous Nephropathy and Familial Sensorineural Deafness

Genetic factors could play an important role in the pathogenesis of idiopathic membranous nephropathy, and a few cases of familial membranous nephropathy have been described: an increased incidence of some HLA antigens as DR3 and others has been reported. We present two brothers with idiopathic membranous nephropathy and sensorineural deafness. HLA typing was performed in the two patients and in the members of the family, and it showed the absence of linkage of an HLA antigen with the renal disease in the family.

Hypocomplementemic Type II Membranoproliferative Glomerulonephritis in a Male Patient with Familial Lecithin-Cholesterol Acyltransferase Deficiency due to Two Different Allelic Mutations

Patients with familial lecithin-cholesterol acyltransferase (LCAT) deficiency very often show progressive glomerulosclerosis with evolution to end-stage disease. High levels of an abnormal lipoprotein (lipoprotein X) cause glomerular capillary endothelial damage. The ultrastructural study of renal biopsy specimens shows characteristic glomerular deposits of membrane-like, cross-striated structures and vacuole structures. The gene encoding for LCAT has been mapped to chromosome 16q22.1, and several mutations of this gene cause LCAT deficiency which is inherited as an autosomal recessive trait and which is characterized by corneal opacities, normochromic normocytic anemia, and renal dysfunction. Herein we report clinical features and renal histological findings concerning a 24-year-old male patient with classical familial LCAT deficiency due to two different allelic mutations: a nonsense mutation inherited from the father and a missense mutation inherited from the mother. Moreover, the patient showed glomerular histological lesions and an immunofluorescent glomerular pattern typical of hypocomplementemic membranoproliferative type II glomerulonephritis (dense-deposit disease). The nature of electron-dense material that characterizes dense-deposit disease is still unkwown, but there are suggestions that some chemical modifications might occur in the renal basement membranes. Therefore, this clinical case might induce to consider possible relations between disorders of the lipoprotein metabolism and renal dense-deposit disease.

Transforming growth factor β blocks cystogenesis by MDCK epithelium in vitro by enhancing the paracellular flux: Implication of collagen V

Transforming growth factor β (TGFβ) determines a nearly complete inhibition of cystogenesis by MDCK cells grown in collagen I‐enriched matrices in vitro. In order to elucidate the mechanism implicated in this phenomenon, we performed a series of experiments aimed at discovering a relevant role of extracellular matrix. TGFβ (2 ng/ml) played a marked stimulatory effect on the expression of extracellular matrix by MDCK with a selective effect on collagen V (three to fourfold increase of protein and mRNA) and in parallel inhibited cystogenesis by 95%. Cotreatment with TGFβ and anti‐collagen V antibodies restored a normal cystogenesis. In analogy, when MDCK cells were grown in three‐dimensional matrices containing collagen I and minor (10%) amounts of collagen V, cystogenesis was once again inhibited by 95%. To characterize the molecular mechanism activated by TGFβ and collagen V, we looked at the electrophysiological characteristics of MDCK monolayers and found a drastic fall of transepithelial electrical resistance (TER) in both conditions. In parallel with the decrease in TER, TGFβ and collagen V also induced the leakage of two high molecular weight tracers, i.e., [3H]‐inulin and 150 kD FITC‐Dextran, suggesting a perturbation of the paracellular permeability. Finally, TGFβ at the relevant concentration did not stimulate apoptosis in our cellular model, as judged by propidium iodide staining and by in situ end labeling of DNA fragments. These observations suggest that TGFβ inhibits cystogenesis by MDCK cells in vitro by altering the collagenic composition of the three‐dimensional milieu where MDCK cells grow and form cysts. The molecular mechanism responsible for inhibition of cystogenesis is the increase of paracellular flux which overcomes the active transport of solutes and water inside cysts. J. Cell. Physiol. 177:214–223, 1998.

Tubular Epithelium Culture from Nephronophthisis-Affected Kidneys: A New Approach to Molecular Disorders of Tubular Cells

Abnormalities of tubular membrane structure and composition have been proposed as the primary defect in nephronophthisis (NEF). In order to characterize the protein composition of tubular cells in NEF, in vitro methods were developed to culture and propagate tubular cells obtained from biopsy fragments. Accordingly, microdissected cortical slices (1 x 3 mm) were first digested with collagenase and DNAse and then grown in RPMI medium supplemented with 10% NU serum and conditioned serum deriving from 3T3 cultures. At confluence, cultured cells from NEF showed characteristics which were typical of normal tubules, i.e. presence of cytokeratin and positivity for succinic dehydrogenase and alkaline phosphatase stainings, and presented no morphological alterations compared to cultured cells from normal tubular epithelium. Moreover, no difference was observed for fibronectin, collagen IV and laminin stains. Analysis by two-dimensional electrophoresis of cellular extracts revealed several changes in protein composition of NEF, the main one being the decrease in NEF cells of a polypeptide with a molecular weight of 120 kD and a pI of 4.8; this polypeptide was a constant finding in normal kidneys. These observations demonstrated that human tubular epithelial cells can be successfully cultured from very small biopsy fragments, which represents a new approach to the study of molecular disorders involving tubular cells in inherited disease. Cultured cells from NEF maintain the same morphological, immunological and cytochemical characteristics as normal tubular cells, but present a few alterations in polypeptide composition which may have pathogenetic relevance. A more careful analysis of these alterations is needed to define the molecular disorder(s) involving the tubule in NEF.

Recurrent Hemolytic Uremic Syndrome: Case Report

Dr. M. Meroni, Servizio di Nefrologia e Dialisi, Ospedale di Vimercate, via C. Battisti 23, I-20059 Vimercate (Italy) Dear Sir, Hemolytic-uremic syndrome (HUS) is a disease of infants and children, but this condition may be found in adults too. Females are more commonly affected, and they usually show a history of oral contraception or recent delivery [1]. At present, however, a clear distinction between HUS and thrombotic thrombocytopenic pur-pura is quite difficult. Recurrent attacks of HUS in adults have been seldom recordered, and the factors responsible for the recurrences were not always known [2]. We have observed a 52-year-old female with acute renal failure in course of classic manifestations of HUS: weakness, petechiae, and ecchymoses in the skin, hema-temesis, melena, and hematuria with mild proteinuria. Hemoglobin was 8.8 g/dl, reticulocytes 21%o, white blood cells, 12,000/mm3, platelets 105,000/mm3, plasma fibri-nogen 140 mg/dl, fibrin split products 80 μg/ml, blood urea nitrogen 131 mg/dl, and serum creatinine 6.22 mg/dl. The renal biopsy specimen has been studied by light, immunoñuorescent, and electron microscopy and showed pathognomonic lesions of HUS (fig. 1). The patient was treated with prednisolone pulses, hemodialysis, plasmapheresis and she left the hospital after 42 days. Serum creatinine was 1.36 mg/dl. In coincidence with abrupt withdrawal of prednisolone, she developed a relapse of HUS with slight renal involvement (serum creatinine 1.79 mg/dl, blood urea nitrogen 32 mg/dl), but with severe involvement of skin, intestinal tract, myocardium, and brain. She died after 25 days in spite of prednisolone, plasmapheretic, and vitamin E treatment. At autopsy the pathologic findings were small microthrombi in brain, myocardium, kidney, thyroid, peritoneum, omentum, jejunum, and ileum. Fig. 1. Electron micrograph from a biopsy specimen showing thickening of the capillary wall, effacement of foot processes, wrinkling of the basement membrane (asterisks), widening of the suben-dothelial space, which contains rarefied and granular material of variable electron density