De novo membranous glomerulonephritis in renal allografts in children

The incidence of de novo membranous glomerulonephritis (MGN) in transplanted kidneys is around 1 to 2%. In our series, of the 310 grafts that were examined by immunofluorescence microscopy (IF), 29 (9.3%) showed subepithelial IgG deposits, a pattern consistent with the diagnosis of MGN. Transplant biopsy had been performed because of the occurrence of proteinuria in 8 patients (pts), for suspected rejection in 16 and systematically in the remaining 9 who had no proteinuria and a normal renal function. In all cases the lesions were identified by IF and were confirmed by electron microscopy (EM) in 14 pts. Granular deposits of IgG were diffuse in 22 cases and segmental in 7. Sequential specimens were available in 17 pts and showed the persistence or the increase of the IgG deposits in all patients but one in whom they had disappeared. Age at transplantation (Tx) ranged from 2 years 3 months to 16 years. Grafts were from cadaveric donors in 27 pts and from living related donors in 2 pts. In none of the recipients was MGN the nephropathy of the native kidneys. With a follow-up of 18 to 74 months, 6 pts never developed a proteinuria. In the remaining 23, proteinuria developed 1 to 70 months after Tx, associated with a nephrotic syndrome (NS) in 6 pts.(ABSTRACT TRUNCATED AT 250 WORDS)

Ontogenesis of angiotensin-I converting enzyme in human kidney

The kidney distribution of angiotensin-I converting enzyme (ACE) was studied in 14 fetuses (11 to 30 weeks old) and 7 children (2 days to 13 years old) by immunohistochemistry using specific antibodies to human kidney ACE. Immunohistochemical techniques included indirect immunofluorescence on cryostat sections of frozen tissue, immunoperoxidase and immunofluorescence of fixed tissue embedded in Paraplast, and immunoelectron microscopy. The ACE distribution in the fetal kidneys was independent of the age of the fetus. ACE was detected in two locations: 1) on the basolateral membranes and primary apical microvilli of epithelial cells from early differentiating proximal tubules; the labeling was intense in brush borders of fully developed proximal tubules; and 2) on glomerular endothelial cells; cells were lined by reaction product as soon as capillaries invaded the inferior cleft of the S-shaped body. Tubular ACE distribution was identical in the postnatal kidneys. The staining of the glomerular endothelium was extremely inconstant. The presence of ACE in proximal tubular cells and glomerular endothelial cells at the beginning of nephron differentiation may indicate that it is involved in the development of nephron function and renal hemodynamic.

Glomerular mesangiolipidosis in Alagille syndrome (arteriohepatic dysplasia)

Alagille syndrome is characterized by the association of chronic cholestasis with a paucity of interlobular bile ducts and a distinctive facies together with cardiovascular, skeletal and eye abnormalities. We examined the kidneys of 26 patients with this syndrome; 22 were under 3 years of age and 4 were 4, 6, 12 and 17 years old, respectively. Eighteen showed glomerular lesions of variable severity characterized by a mesangiolipidosis. In the 8 lesser affected patients light microscopy (LM) disclosed a fibrillar appearance of the mesangium, and electron microscopy (EM) showed lipid vacuoles widespread in the mesangial matrix. In the 10 patients who were affected to a greater degree LM and EM showed, in addition to the mesangial matrix changes, the presence of mesangial foam cells. Clinical signs of renal involvement were mild in all patients except for one who died from chronic renal failure at 8 months of age. The extent of mesangiolipidosis was not related to age but to the degree of cholestasis, the most severe lesions being observed in patients aged 3, 6, 8, and 14 months. The glomerular lesions observed in Alagille syndrome are strikingly similar to those observed in adults with lecithin-cholesterol acyl transferase deficiency and other conditions characterized by an increase in plasma lipoproteins rich in free cholesterol and in phospholipids. We conclude that glomerular involvement should be added to the characteristic features of Alagille syndrome. Also we found that the lipid deposition in the glomeruli of patients with Alagille syndrome is related to an abnormal lipid metabolism, which is the consequence of severe cholestasis. The most striking feature of our study is the early detection of the glomerular lesions, contrasting with the lack of overt clinical renal disease. Renal failure may be a major complication for patients with this syndrome in adulthood.

Ocular changes in some progressive hereditary nephropathies

Ocular involvement is a common feature of three hereditary nephropathies: cystinosis, nephronophthisis and Alport's syndrome. The follow-up of 25 cases of infantile cystinosis over a period of 26 years demonstrated that the corneal and retinal epithelium were affected in the same way as the kidney epithelium. Corneal involvement induced photophobia and discomfort, but actual blindness was mainly due to retinal involvement, and therefore no corneal graft was performed. The use of topical cysteamine appears to be promising, but its production raises many questions so no definitive conclusions may be made. Since 1965, 51 patients with nephronophthisis have had ocular examinations; all patients had characteristic clinical symptoms and histological findings. The first group, which consisted of 18 children, all under 10 years of age, was found to have obvious chorioretinal degeneration. The second group, which consisted of 11 children, had a normal ocular examination and normal electroretinogram (ERG). The third group, consisting of 22 children, had a normal clinical examination but ERG tracings with variable alterations. In 28 instances of Alport's syndrome, two types of ocular abnormalities have been observed. In six cases, an anterior lenticonus was noted, which caused a major decline in visual acuity. Retinopathy, which did not affect vision, was observed in 13 cases.

Variants of Alport's syndrome

Variants of Alport's syndrome include mainly those associated with hereditary macrothrombocytopenia (and occasionally leukocyte inclusions) or with esophageal, tracheobronchial and genital leiomyomatosis. Within Alport's syndrome there appears to be no justification for differentiating those with nephritis and deafness from those with nephritis alone. However, in indirect immunofluorescence studies using the mouse monoclonal antibody, MCA-P1, which recognizes the glomerular basement membrane (GBM), reduced or absent binding was found in 20 of 42 cases of hereditary nephritis. Most of these showed typical ultrastructural GMB changes. These results suggest that there is probably a subset of patients characterized by typical GBM lesions and an absence, inaccessibility or abnormality of the GBM antigen recognized by MCA-P1.

Late symptoms in infantile cystinosis

Late symptoms of infantile cystinosis were evaluated in 19 patients aged 15-26 years who had a high graft survival following kidney transplantation. The end-stage cystinotic kidney was responsible for renal hypertension in 5 patients following grafts. Photophobia did not increase in relation to age, but 3 patients became blind and 1 lost the sight in one eye at 25 years of age. Two patients developed clinical symptoms of hypothyroidism, and 15 other patients had a compensated hypothyroidism. Four patients developed permanent insulin-dependent diabetes and 2 developed transient insulin-dependent diabetes after transplantation. The oral glucose tolerance test was abnormal in 11 of 14 patients on low-dose prednisone. Liver enlargement was noted in 10 cases, but only 3 patients developed clinical symptoms of portal hypertension. Symptoms of hypersplenism were observed in 6 cases leading to splenectomy. Repeat gross epistaxis was observed in 7 of the patients when on dialysis and persisted after transplantation in 1 patient, who died from nasal bleeding. A particular encephalopathy developed in 2 patients at the ages of 17 and 24, characterized by speech difficulties, pyramidal symptoms and cranial nerve deficit; one died at the age of 21. The mean adult height of these patients was 136.5 cm in males and 124 cm in females, and their psychosocial adjustment was related to the extra-renal complications of cystinosis rather than to the renal status.

Ocular changes in long-term evolution of infantile cystinosis

Infantile cystinosis is an autosomal recessive lysosomal disorder of aminoacid metabolism leading to a storage of cystine crystals in the cells of many tissues, but mainly in the kidney and the eye. The ocular symptoms and long term evolution were studied in a series of 25 patients at the Enfants Malades Hospital. The follow-up over 26 years demonstrated that infantile cystinosis affected mainly corneal and retinal epithelium just as it affected the kidney epithelium. Corneal involvement was a constant finding after one year of age. It induced photophobia, which appeared between three and four years when a superficial punctate keratopathy appeared. A characteristic retinopathy was observed as early as three years of age. It was constantly present at seven years of age and caused loss of vision. When ERG results were compared to the most recent measurement of visual acuity, a correlation was observed between retinopathy and visual defect. For this reason, no corneal grafts were performed. The use of topic cysteamine appeared promising but no definitive conclusions could be made.

Renal involvement in juvenile chronic arthritis: clinical and pathologic features

Over an 18-year period, renal involvement was diagnosed in 13 patients, who represent 1% of the total juvenile chronic arthritis population referred to us. All had severe arthritis. This study illustrates the importance of renal biopsy and indicates that renal involvement in juvenile chronic arthritis is a heterogeneous group of diseases, with a variety of causes. In eight patients with nephrotic syndrome, renal biopsy revealed amyloidosis. One rapidly died of diffuse amyloidosis and infection. The other seven received chlorambucil. Disappearance of proteinuria was noted in three of them. Four patients have persistent proteinuria but normal serum creatinine. It is suggested that, despite the long-term oncogenic risk of the drug, chlorambucil may be beneficial in patients with amyloid deposits. In one patient, the nephrotic syndrome was attributed to systemic lupus erythematosus, and in another, the chance association of an arthritis and nephrotic syndrome with minimal glomerular changes was considered. Although drug responsibility is difficult to determine in these patients receiving several medications in association, the renal involvement presented by the remaining three patients was probably related to drug(s). Moreover, it is possible that the effect of the association of medications is deleterious to the kidney. Drug-induced nephropathy is usually reversible when drugs are stopped. Unfortunately, because of persistent joint pain, these patients will continue to require pain-relieving drugs over prolonged periods.

Ontogenesis of 28 kDa vitamin D-induced calcium-binding protein in human kidney

The kidney distribution of 28 kDa vitamin D-induced calcium binding protein (CaBP) was studied in 15 fetuses (11 to 33 weeks old), six children and adults (12 days to 32 years old) by immunocytochemistry using a specific antibody to rat renal 28 kDa CaBP. Similar results were obtained on frozen and fixed tissues. Kidneys from one adult and three fetuses were studied by immunoelectronmicroscopy for antigen localization at the subcellular level using the indirect immunoperoxidase technique. The 28 kDa CaBP was present in all kidneys from the eleventh week of gestation. At that stage, all deep parts of collecting ducts were homogeneously stained and a few distal tubules located in the deep cortex were intensely labeled. No labeling was observed in the early stage of nephron differentiation (S-body). 28 kDa CaBP distribution changed with kidney maturation. There was a progressive reduction of the deep part of collecting duct labeling and a concomitant increase in the number and intensity of stained distal tubular cells. At the ultrastructural level, 28 kDa CaBP was observed in the cytosol and the nuclear euchromatin. Our study demonstrates the early cellular synthesis of 28 kDa CaBP and its transient expression by deep collecting duct cells during early fetal life, at a time when only a few distal convoluted tubular cells synthetize it.

H deficiency in two brothers with atypical dense intramembranous deposit disease

We report an H deficiency in two Algerian brothers who had early-onset glomerulonephritis. In addition, one suffered from serious lung infections. The H deficiency was defined by undetectable CH50 and AP50, and low levels of H, C3 and B (less than 10% of normal levels). I and classical pathway components, including C4-bp were normal. CR1 was present on both patients' erythrocytes. No nephritic factor or other circulating alternative pathway activator was detected. The parents, who are first cousins, and a healthy brother and sister had half-normal levels of H. These findings favor an autosomal recessive transmission of the H defect. Although by electron microscopy renal biopsies from both patients were typical for dense intramembranous deposit disease, immunofluorescence microscopy showed an atypical pattern with abundant granular C3 deposits within the mesangium and along the capillary walls. Alternative pathway activators, possibly related to dense deposits, may allow the formation of membrane-associated C3/C5 convertases, unusually stable in the absence of H, since C5, C6, C7, C8 and C9 levels were decreased in both patients. This observation may represent an interesting clue to the relationship between nephritic factor, alternative pathway activation, and dense intramembranous deposit disease.

[Charcot-Marie-Tooth disease and glomerular nephropathy]

Anatomoclinical profile and follow-up of a glomerular nephropathy in a prepubertal girl with Charcot-Marie-Tooth disease is reported; striking common pattern features with the few cases previously published of such an association strongly suggest that renal involvement is possible in sensorineural neuropathies and may be one major factor in the overall prognosis of the disease.

Distribution of extracellular matrix glycoproteins during normal development of human kidney. An immunohistochemical study

The distribution of types I, III, and IV collagens, fibronectin, laminin, and heparan sulfate proteoglycan during human fetal kidney development has been studied by indirect immunofluorescence. Fibronectin and interstitial collagens types I and III are present in undifferentiated mesenchyme, whereas the intrinsic basement membrane components, type IV collagen, laminin, and heparan sulfate proteoglycan are not detected. In differentiated cortex, types I and III collagens are detected only as interstitial connective fibers, whereas fibronectin is found in both interstitium and glomeruli where its distribution is dependent on the stage of maturation. It is found in both the mesangium and along capillary walls of immature glomeruli, and principally in the mesangium of mature ones. Basement membrane components delineated the branching ureteric bud. They also outlined the structures of the earliest stage of nephrogenesis (epithelial differentiation). In mature nephrons, they are found along glomerular, capsular, and tubular basement membranes.

The nephropathy associated with male pseudohermaphroditism and Wilms' tumor (Drash syndrome): a distinctive glomerular lesion--report of 10 cases

We report on 10 children, less than 2 years of age, who presented with a genuine type of glomerulopathy: diffuse mesangial sclerosis. In 5, the nephropathy was associated with male pseudohermaphroditism (MPH) and Wilms' tumor (WT); in 3 with MPH and in 2 with WT. The nephropathy was characterized by its very early onset, between the age of 2 weeks and 18 months. Eight patients presented with a nephrotic syndrome with (7 cases) or without (1 case) hypertension. All, but one, who is in advanced RF at 11 years of age, progressed to chronic or end-stage renal failure (ESRF) within a few months to 2 years from the onset. One additional child presented with advanced renal failure at the age of 8 months and the last one, who was hypertensive, developed an anuria related to thrombosis of renal veins at 1 year of age. Drash syndrome is characterized by the association of a "nephron disorder" with MPH and WT. We propose, on the basis of our histological findings, to extend the concept of Drash syndrome to patients who, in addition to the nephropathy, have either WT or MPH and to consider the distinctive glomerular lesions presented by all these patients as their common denominator. The pathogenesis of this glomerulopathy is obscure. Its early onset, its association with a dysembryoplastic tumor and/or with gonadal dysgenesis both suggest an antenatal dysgenetic process.

Ontogenesis of the glomerular C3b receptor (CR1) in fetal human kidney

Ontogenesis of the glomerular C3b receptor (CR1) was studied in kidneys from 16 fetuses aged from 9 to 32 weeks, using immunohistochemical techniques and the F(ab')2 fragment of a monospecific rabbit antibody to CR1, and adherence of C3b-coated sheep erythrocytes. By indirect immunofluoresence, anti-CR1 stained presumptive glomerular epithelium from the end of the S-body stage of nephron differentiation. Staining increased with visceral epithelial cell proliferation and with differentiation of the nephron from the subcortical to the juxtamedullary part of the fetal kidney. Using electron microscopy and an indirect immunoperoxidase technique, CR1 antigen was detected on the plasma membrane in the basolateral part of primitive podocytes from the late S-body stage, following the acquisition by podocytes of the capacity to synthetize a basal lamina. Endothelial cells and mesangial cells did not stain for CR1 antigen. CR1 antigen was expressed by podocytes from the same stage of glomerular differentiation as was the CALLA antigen. Glomerular expression of CR1 on podocytes preceded that of Ia on glomerular endothelial cells. C3b-bearing sheep erythrocytes only adhered to clover-like lobulated glomeruli at a late stage of glomerular differentiation. Glomerular CR1, a specific marker of glomerular capillary epithelial cells is one of the earliest markers expressed by resident glomerular cells during renal ontogenesis.

Genetic heterogeneity of Alport syndrome

Forty-one families have been studied with stringent diagnostic criteria of Alport syndrome: proven renal disease with hematuria affecting at least two relatives, neural hearing loss in at least one affected individual, and evolution to renal failure in at least one affected individual. The proportion of affected offsprings of affected females does not significantly differ from the ratio expected for a dominant trait. The descendance of affected males shows a lack of affected males. In four families, with parental consanguinity and nonaffected parents, the findings agree with an autosomal recessive inheritance. Study of quantitative traits such as death or renal death among brothers, uncle-nephew pairs and whole families shows evident intra-familial resemblances. We conclude that Alport syndrome seems to be a heterogeneous state composed of a number of genetically distinct syndromes, with an autosomal dominant, an X-linked dominant, and an autosomal recessive form.

Oligomeganephronic renal hypoplasia with tapetoretinal degeneration. Report of one case with ultrastructural study of the renal biopsy

Bilateral renal hypoplasia with oligomeganephronia, associated with bilateral tapetoretinal degeneration was observed in a child; this association has been reported only once before. Light, ultrastructural and immunofluorescent microscopic studies of the renal tissue were performed. The glomeruli were few and hypertrophic, with numerous mesangial cells, mesangial deposits, focal glomerular sclerosis and prominent thickened basement membrane. Two types of tubular changes were observed: focal necrosis of proximal tubules and focal atrophy of tubules surrounded by a thickened basement membrane. Mild fibrosis with few lymphocytes could be observed in the interstitium. A congenital reduction in the number of nephrons, related to a yet unknown pathological process may explain these morphological changes in part.

The dotted corticomedullary junction: a sonographic indicator of small-vessel disease in hypertensive children

Six children with hypertension are reported where ultrasound showed a striking increase in the intrarenal vascular echoes. This pattern, the dotted corticomedullary junction, appears to represent a diffuse calcifying process involving the elastic fibers of the wall of small arteries.

Renin biosynthesis by human tumoral juxtaglomerular cells. Evidences for a renin precursor

Renin biosynthesis was studied in a juxtaglomerular cell tumor. The tumoral tissue had a high renin content (180 Goldblatt Units/g of tissue), was heavily stained by immunofluorescence using human renin antiserum, and exhibited numerous characteristic secretory granules by electron microscopy. In one series of experiments, renin biosynthesis was studied in tissue slices, by following the incorporation of radiolabeled amino acids into specific immunoprecipitable renin. Time course studies showed that renin was first synthesized in a high molecular weight form, 55,000 mol wt, i.e., 10,000 mol wt higher than that of active renin, and was then converted into a 44,000-mol wt form. In a second series of experiments renin tumoral cells were cultured. Small, round, birefringent cells obtained after collagenase digestion produced renin in both primary culture and subculture media. After 5 d most of the renin found in the culture medium was inactive, but could be activated by trypsin treatment. The tumoral tissue exhibited a strong renin immunofluorescence and numerous secretory granules were observed by electron microscopy. In contrast, the renin-producing cells isolated from this tumor and grown in culture showed little renin immunofluorescence and no secretory granule could be observed. The renin-producing cells in primary culture and subculture were pulsed with radiolabeled amino acids, and immunoprecipitable radiolabeled renin was found in the culture media, thus demonstrating the actual biosynthesis of the enzyme. This renin was not stored inside cultured cells but was rapidly released into the medium and had a molecular weight of 55,000. No conversion of this inactive high molecular weight renin into the active, 44,000 mol wt form of renin was observed. We postulate the existence of two pathways for the processing, packaging, and secretion of renin in the tumoral cells: in juxtaglomerular cells of tumoral tissue renin is synthesized as a preprorenin and rapidly converted into prorenin (55,000 mol wt), which is in turn packaged in secretory granules where it is processed into active renin (44,000 mol wt) and finally secreted; in the cultured tumoral cells renin is still biosynthesized as a preprorenin molecule and then converted into prorenin, but is neither stored as granules nor processed into active renin. In this case the renin is released in an inactive form.

Release of platelet-activating factor, slow-reacting substance, and vasoactive amines from isolated rat kidneys

The present work brings the first evidence for the simultaneous release of Paf-acether (platelet-activating factor), slow-reacting substance (SRS), histamine, and serotonin from isolated rat kidneys stimulated with ionophore A 23187. However, with compound 48/80 we detected only SRS, histamine, and serotonin. Upon addition of antigen, kidneys from sensitized rats released Paf-acether and SRS of anaphylaxis. Paf-acether released in the perfusate was identified by its ability to aggregate aspirin-treated washed rabbit platelets in the presence of an ADP scavenger complex. It was also characterized by its inactivation by phospholipase A2, and it was eluted from high pressure liquid chromatography (HPLC) after 16 to 18 min, a retention identical to that of synthetic Paf-acether, that is, between sphingomyelin and lysophosphatidylcholine. The biological activity of SRS was detected after several purification steps including Amberlite XAD-2 and reverse phase HPLC (RP-HPLC). Kidney SRS exhibited a typical spasmogenic activity in isolated guinea-pig ileum preparation that was reversed by FPL 55712. When kidneys were incubated with [3H]arachidonic acid, radioactivity and biological activity comigrated in RP-HPLC with leukotrienes C and D. These results indicate that the kidney is capable of actively released inflammatory mediators.

Adverse effect of proteins on remnant kidney: dissociation from that of other nutrients

Several experiments have shown that deterioration of renal parenchyma after reduction of functional mass is affected by the protein content of the diet. The respective role of proteins and that of other nutrients that vary with proteins were never clearly separated. Three groups of 9 uremic rats received diets differing exclusively in protein (casein) content, which was 8% (group 1), 16% (group 2), and 32% (group 3). Energy and minerals were maintained identical. Food intake was similar in groups 1 and 2 and was lower in group 3. Mortality rate remained closely related to protein intake. Of group 3 rats, 78% died within 10 weeks and 100% within 15 weeks. Of group 2 rats, 56% were dead at week 15, and 100% at week 30. Mortality occurred significantly later in group-1 rats fed the lowest protein diet. Histology of remnant kidneys showed severe glomerular and tubular damage, with no or little calcium deposits despite normal phosphorus diet and frequent hyperphosphatemia. These data suggest that protein intake, independent of any other nutrient, influences survival by accelerating the renal damage in rats with reduced kidney mass.

Adverse effect of indomethacin in experimental chronic nephrosis

The effects of long-term indomethacin therapy were studied in rats with chronic nephrosis induced by puromycin of aminonucleoside (PAN). Fifteen PAN rats received indomethacin (2 mg/kg/d) administered by daily gavages, and fifteen received glucose. A control group received indomethacin but no PAN. Three to five animals per group were sacrificed monthly. Proteinuria was similar in both PAN rat groups. Renal function and histology were normal in the control rats. In the PAN animals, renal failure developed earlier in the treated rats than in the others. Histological examination revealed in all PAN rats early tubulo-interstitial lesions and progressive glomerular damage. The pattern of the lesions was identical in both PAN rats, but the glomerular changes developed earlier, were more diffuse and more severe in the indomethacin treated rats. Thus, indomethacin resulted in an accelerated destruction of the glomeruli in experimental nephrosis. Such a deleterious effect remains unexplained, and its relevance to human disease is not demonstrated.

Pre- and posttransplant glomerulonephritis in a case of sarcoidosis

A 39-year-old woman with documented sarcoidosis and membranous glomerulonephritis (GN) with renal failure received a kidney from her identical twin. A few months after transplantation a proliferative GN appeared with hematuria, proteinuria and progressive renal failure over 2 years. Indeed the occurrence of GN in patients with sarcoidosis raises the question of whether the relationship between these two conditions is causal or fortuitous. This report suggests that GN is secondary to sarcoidosis.

Importance of proteins in the deterioration of the remnant kidneys, independently of other nutrients

Several experiments have shown that deterioration of renal parenchyma after reduction of functional mass is affected by the protein content of the diet. The respective role of proteins and that of other nutrients particularly phosphorus which varies with proteins was never clearly separated. Three groups of 9 uremic rats U I, U II, U III, received three diets differing exclusively in their protein content, which was supplied by casein and was respectively 8%, 16% and 32%. Other nutrients were maintained identical, including energy and minerals. Food intake was similar in U I and U II rats and was lower in U III rats. Mortality rate remained closely related to protein intake. Of U III rats, 78% died within 10 weeks and 100% within 15 weeks. Of U II rats, 56% were dead at week 15, and 100% at week 30. Mortality occurred significantly later in U I rats fed the lowest protein diet. Histology of remnant kidneys showed severe glomerular and tubular damage, with no or little calcium deposits despite normal phosphorus diet and frequent hyperphosphoremia. In conclusion, protein intake influences survival by accelerating the renal damage in rats with reduced kidney mass independently of any other nutrient.