Juxtaglomerular body abnormalities in youth-onset diabetic subjects.

Abnormal microalbuminuria in insulin-dependent diabetic subjects (IDDS) is significantly associated with pre-clinical nephropathy. In youth-onset IDDS declining plasma renin activity is significantly associated with improved albumin excretion, while persistently elevated renin activity is associated with continued abnormal microalbuminuria. To determine if these changes are reflected in changes in cell count in the juxtaglomerular body and if biopsy findings correlate with abnormal microalbuminuria, renal tissue of 20 IDDS (Study IDDS) ages 16 to 31 years, evaluated concurrently for plasma renin activity and microalbuminuria, were examined by light microscopy. Biopsy or autopsy specimens from 21 normal subjects and 32 IDDS (Non-Study IDDS), ages 2 to 25, were also examined. Specimens from the majority of prepubertal and all pubertal and postpubertal Non-Study IDDS and all Study IDDS independently of status of microalbuminuria had morphologic abnormalities. Normal or mesangially expanded glomeruli were found in association with expanded juxta-glomerular bodies and increased cell number, or with sclerotic bodies and decreased cell number. Sclerosis of juxtaglomerular bodies occurred independently of glomerular sclerosis. The highest percentage of glomeruli with expanded juxtaglomerular bodies and high cell count was present in specimens of Study IDDS with the most abnormal levels of microalbuminuria. T lymphocytes, noted within juxtaglomerular bodies, were present in specimens of 62% of the 52 Study and Non-Study IDDS. Abnormalities of the juxtaglomerular body are distinctive features of renal pathology in IDDS. T lymphocytes in the endocrine juxtaglomerular body suggest the presence of an autoimmune process. Confirmatory studies are necessary.

Acute serum sickness in normal and C6 deficient rabbits: role of membrane attack complex.

Acute serum sickness was induced in New Zealand White (NZW) and in C6 deficient (C6D) rabbits, to compare the histology, immunofluorescence, especially distribution of poly C9 (MAC), and electron microscopic characteristics of the disease in each strain. Glomerulonephritis and albuminuria of comparable extent occurred in 13/17 NZW and 4/8 C6D rabbits. In NZW rabbits with albuminuria an early intense glomerular infiltration by mononuclear cells was associated with focal small fine granular glomerular basement membrane (GBM) deposits of IgG and BSA and more diffuse and larger deposits of C3 and MAC. After the disappearance of monocytes and decrease in mesangial cell proliferation, development of large subepithelial GBM deposits rich in all immune reactants was observed in NZB rabbits. In C6D rabbits with albuminuria a similar monocytic infiltrate occurred, but no association with IgG and C3 GBM immune deposits was noted. No deposits of MAC and no large subepithelial GBM 'humps' were observed in C6D rabbits. We conclude that the exudative (monocytic) phase of glomerular injury and albuminuria in acute serum sickness nephritis are not dependent upon terminal complement components, but the subsequent formation of large subepithelial GBM deposits does not occur in this model in the absence of MAC.

Heparan sulfate proteoglycan in the glomerular basement membrane in type 1 diabetes mellitus.

Heparan sulfate proteoglycans (HSPG) are negatively charged constituents of the renal extracellular matrix including the glomerular basement membrane (GBM) and mesangial matrix. Biochemical and functional studies of patients with type-1 insulin dependent diabetes mellitus (IDDM) suggest that alterations of HSPG may occur in diabetic nephropathy. We have utilized a specific cytochemical method and electron microscopy to quantitate the distribution of HSPG in the GBM of 10 normal people and in 16 IDDM patients with a spectrum of clinical and structural changes. Enzyme incubation studies of normal infant kidney demonstrated that heparitinase removed 94% of the stainable anionic sites in the lamina rara externa (LRE) and 77% of the sites in the lamina rara interna (LRI) of the GBM. In contrast, incubation in the enzyme chondroitinase ABC did not reduce the number of sites in the LRE but reduced the number of sites in the LRI by 26%. The HSPG anionic sites in normal subjects were distributed in the LRE as 20.9 +/- 1.3, and in the LRI as 13.1 +/- 2.2 per micron GBM length. Anionic sites were slightly reduced (19.6 +/- 1.3, P less than 0.04) in the LRE of IDDM patients with normal urinary albumin excretion rates (UAE), or microalbuminuria, and were reduced in both the LRE and LRI of IDDM patients with clinical proteinuria (13.1 +/- 2.3, P less than 0.001 and 8.9 +/- 2.1, P less than 0.001, respectively). The number of anionic sites in the LRE and LRI, respectively, correlated with UAE (r = +0.78, P less than 0.001, r = +0.58, P less than 0.02), with GBM thickness (LRE, r = +0.81, P less than 0.001; LRI, r = +0.67, P less than 0.01) and with the volume fraction of mesangium (LRE, r = +0.59, P less than 0.02; LRI, r = +0.58, P less than 0.03). These data confirm earlier biochemical findings of a reduction of HSPG in the GBM in advanced diabetic nephropathy but do not provide evidence for the loss of HSPG in the GBM as a mechanism for early microalbuminuria.

Explantation of mesangial cell 'hillocks': a method for obtaining human mesangial cells in culture.

A simple method is presented for selective cell culture of human mesangial cells using explantation of mesangial cell hillocks. Glomeruli which had been incubated with collagenase were explanted on plastic tissue culture flasks. Three to 6 weeks after explantation, a rapidly growing multilayer of elongated mesangial cells was observed to grow over the previously established monolayer of glomerular epithelial cells, ultimately forming multiple nodular foci of mesangial cells or 'mesangial cell hillocks'. By explanting mesangial cell hillocks selectively, pure mesangial cell cultures were easily obtained. When compared with mesangial cells grown in mixed cultures from glomerular explants, the hillock-derived cells were identical in morphology, growth characteristics, cell markers and synthesis of extracellular matrix. This system provides a simple method for the isolation of human mesangial cells in culture.

Steroid-dependent nephrotic syndrome following renal transplantation for congenital nephrotic syndrome.

A boy developed recurrent steroid-responsive nephrotic syndrome following renal transplantation for congenital nephrotic syndrome. The first episode was associated with mild tubulointerstitial rejection on kidney biopsy. Subsequent episodes showed normal histology by light microscopy and epithelial foot process fusion on electron microscopy, consistent with minimal change nephrotic syndrome. Serum analysis for soluble immune response suppressor was negative pre-nephrectomy, positive during each bout of nephrotic syndrome, and negative during each remission. This case represents de novo occurrence of steroid-sensitive minimal change nephrotic syndrome following renal transplantation for congenital nephrotic syndrome. We stress the need for histological examination of the renal allograft to diagnose rejection, recurrent disease, or de novo disease.

Early bladder outlet obstruction in fetal lambs induces renal dysplasia and the prune-belly syndrome.

A model of posterior urethral valves in fetal lambs was developed in order to evaluate the effect of intrauterine urinary obstruction on the developing kidney. Complete urethral obstruction was induced in five fetal lambs at 43 to 45 days of gestation. Two control fetal lambs underwent sham operations. At full term (140 days), two of the five experimental lambs and both control lambs were available for postmortem examination. Results of gross and histological examination of the control lambs were normal. In contrast, the kidneys of the experimental lambs were markedly asymmetrical in size. Histological examination of the kidneys in experimental lambs showed cystic dilatation of the collecting ducts and occasional cystic dilatation of Bowman's spaces, features compatible with obstruction. Also noted were peripheral cortical cysts and primitive tubules lined with cuboidal epithelium and surrounded by fibromuscular collarettes, characteristic of renal dysplasia. One of the infant lambs had many characteristics of the prune-belly syndrome, including a wrinkled, markedly distended abdomen, deficient abdominal wall musculature, flared chest wall, limb deformities, and undescended testes. These results suggest that early in utero urethral obstruction (at the beginning of the second third of gestation) causes renal dysplasia. The results also support the hypothesis that the prune-belly syndrome results from abdominal distention that occurs early in gestation.

Proteinuria in a child with sialidosis: case report and histological studies.

A 9-year-old body with sialidosis had nephrotic-range proteinuria. Histological studies demonstrated massive distension of renal cells, particularly glomerular visceral epithelial cells, by cytoplasmic vesicles which contained material reactive with concanavalin A and wheat-germ agglutinin. In addition, some glomeruli exhibited segmental mesangial thickening or glomerulosclerosis. Ultrastructurally, focal detachment of visceral epithelial cells from the underlying glomerular basement membrane was observed. We postulate that glomerular visceral epithelial cell dysfunction may underlie the proteinuria and focal glomerulosclerosis exhibited by this patient. Hyperfiltration, as suggested by the child's elevated creatinine clearances, may be a contributing factor.

Anionic sites in the human kidney: ex vivo perfusion studies.

Heparan sulfate-proteoglycan (HS-PG) anionic sites located in the glomerular basement membrane (GBM) are thought to contribute to glomerular permselectivity in man. The number and distribution of HS-PG anionic sites in the GBM and mesangial matrix of seven normal human kidneys and three kidneys from children with congenital nephrotic syndrome (CNS) were evaluated by ex vivo perfusion of polyethyleneimine (PEI; Mr 40,000 to 60,000). In the normal kidneys lamina rara externa (LRE) anionic sites (21.8 +/- 2.4 per 1000-nm actual GBM length) were well labeled and similar to those obtained by immersion staining of fixed tissue with Mr 1200 PEI. Lamina rara interna (LRI) anionic site number (22.0 +/- 2.6 per 1000-nm GBM) and appearance were better demonstrated by PEI perfusion than by the immersion technique. PEI perfusion also demonstrated regularly arranged (60 to 120 nm apart) mesangial matrix anionic sites (20- to 30-nm diameter) at 4.09 +/- 0.59 x 10(3) sites per nm2 matrix. PEI perfusion of three kidneys from children with CNS demonstrated decreased (16.3 +/- 1.9 per 1000-nm GBM) LRE anionic sites and normal LRI anionic sites (22.0 +/- 3.5 per 1000-nm GBM). Mesangial volume was increased, and mesangial anionic sites were less frequent (3.24 +/- 0.42 x 10(3) per nm2 matrix) and irregular in size in the children with CNS.(ABSTRACT TRUNCATED AT 250 WORDS)

Lymphohaemopoietic antigens of cultured human glomerular epithelial cells.

Glomerular visceral epithelial cells (GVEC) from normal human glomeruli were grown in tissue culture. Cell surface markers were studied by immunofluorescence microscopy using antibodies against lymphohaemopoietic differentiation antigens which are known to be present early (BA-1, OKB2, BA-2) and late (J5, anti CR1) in renal ontogenesis. Like foetal human glomerular epithelium, the cultured cells reacted with BA-1 and OKB2 (identifying an antigen expressed on B cells and polymorphonuclear leucocytes), and BA-2 (leukaemia-associated antigen), but were consistently negative for CR1 (C3b receptor); J5 which identifies the common acute lymphoblastic leukaemia antigen (CALLA) stained variably. Reactivity with antimyosin or anti factor VIII were absent. The cells produced an extracellular matrix containing laminin, type IV collagen, and fibronectin. This study supports the notion that GVEC undergo dedifferentiation as shown by the acquisition of lymphohaemopoietic differentiation antigens present early in renal ontogeny. In addition, the production of extracellular matrix constituents in vitro may be useful for the investigation of human glomerular basement membranes.

Anaphylactoid purpura: characteristics of 16 patients who progressed to renal failure.

Renal insufficiency occurs in at least 1.5% of children with anaphylactoid purpura (AP). We reviewed the records of 16 children who developed end-stage renal disease (ESRD group) secondary to AP and matched them for age, era of onset, renal histology, and clinical severity at onset with 16 children who had AP but whose creatine clearance returned to and remained normal (recovery group). We reviewed creatinine clearances at 1, 3, 5, and 10 years after onset. A creatinine clearance greater than 70 ml/min per 1.73 m2 was present in 50% of the patients in the ESRD group at 3 years and in 25% at 5 years after onset. In contrast, all patients in the recovery group had a creatinine clearance greater than 70 ml/min per 1.73 m2 by 3 years (7 of 16 had a creatinine clearance greater than 125 ml/min per 1.73 m2) and all were normal 95-125 ml/min per 1.73 m2) by 5 years. Thus, the presence of an increased creatinine clearance (greater than 125 ml/min per 1.73 m2) at 3 years predicted recovery, while failure to reach a creatinine clearance of greater than 70 ml/min per 1.73 m2 at 3 years predicted progression to ESRD. There was no evidence of recurrent systemic AP or nephritis in the 14 patients who underwent renal allograft transplantation. We conclude that long-term evaluation of patients over many years is required to identify those who will progress to ESRD from AP and that recurrence of AP in the renal transplant is uncommon.

Ultrastructural localization of the membrane attack complex of complement in human renal tissues.

Utilizing a monoclonal antibody (Poly C9-MA) to a neoantigen of the C9 portion of the membrane attack complex of complement (MAC), immunoelectron (IEM) and immunofluorescent (IF) microscopy were performed on kidney tissue from normal humans and patients with insulin-dependent diabetes mellitus (IDDM) and type II membrano-proliferative glomerulonephritis (MPGN II). Comparative studies were conducted using polyclonal antibodies to human C3, C5, IgG, IgA, and IgM. In normal human tissue, there was a close correlation between increasing chronologic age and the quantity of MAC deposited in the mesangial stalk, along the interstitial aspect of and within tubular basement membranes (TBMs) and in arteriolar walls. IF of kidney tissues from 12 patients with IDDM with varying degrees of mesangial expansion and glomerulosclerosis demonstrated a direct relationship between the degree of tissue damage and the amount of MAC deposited in the mesangium. IEM of three normal and four diabetic specimens revealed reaction product of Poly C9-MA on linear and circular membranous structures within the mesangium, TBMs, and vessel walls, and within the glomerular basement membranes (GBMs) in diabetic subjects. Evidence is presented that these structures, which have been previously described by routine electron microscopy, represent cellular debris in these loci on which Poly C9-MA has been deposited. In MPGN II, Poly C9-MA and C3 were distributed within subepithelial deposits, along either side of the dense deposits (DDs) within the GBMs and TBMs, and around circular masses of DDs within the mesangium.(ABSTRACT TRUNCATED AT 250 WORDS)

Glomerular basement membrane anionic charge site changes early in aminonucleoside nephrosis.

Alterations of glomerular basement membrane (GBM) anionic (charge sites, CSs) in the development of proteinuria in a model of idiopathic nephrotic syndrome in man (puromycin aminonucleoside nephrotic syndrome [PAN] in the rat) were assessed quantitatively and sequentially early after disease induction. GBM CSs (known to consist mainly of heparan sulfate-rich proteoglycans) were stained in vivo and, in a separate group of animals by an in vitro method, with the cationic marker polyethyleneimine (PEI) studied by electron microscopic examination. Four hours after administration of PAN, there was a significant decrease in GBM lamina rara externa CSs: 18 +/- 0.7 versus 22.0 +/- 2.2 per 1000 nm GBM in controls by PEI injection and 17.2 +/- 2.7 versus 21.1 +/- 1.6 per 1000 nm GBM in controls by PEI in vitro staining. This CS alteration coincided with changes in glomerular epithelial cell morphologic characteristics (increased cytoplasmic organelles and rough endoplasmic reticulum) and preceded the detection of foot process broadening (at 24 hours) and increased urinary albuminuria (suggested at 12-24 hours, statistically significant at 36-48 hours). These results suggest that GBM CS-heparan sulfate proteoglycan alterations consisting of either decreased number and/or less anionic charge occur early in PAN and support a role for glomerular epithelial cell maintenance of GBM CS for normal glomerular function.

Localization and quantitation of anionic charge sites in fetal and neonatal alveolar basement membranes.

A method utilizing biopsy sized samples of lung for anionic charge site localization in alveolar and capillary basement membranes in human tissue is discussed. Tissue fixed in either paraformaldehyde-lysine-periodate or 1% paraformaldehyde with 0.05% glutaraldehyde, cut into 30 mu sections, and incubated with the cationic probe, polyethyleneimine, was processed for electron microscopic analysis using standard techniques. Anionic charge sites were identified and regularly distributed in increments of approximately 40-50 nm in the lamina rara externa of the alveolar basement membrane, with lesser amounts found in the lamina rara interna and lamina densa. Anionic charge sites were also demonstrated in the interstitial portion of the capillary basement membrane and on cell surfaces. These methods can be used to more broadly define the localization of anionic charge sites in human lung tissue in both normal and pathologic states.