Gene expression for endothelins and their receptors in glomeruli of diabetic rats

The present study was designed to assess levels of messenger RNA encoding for endothelin-1, endothelin-3, and endothelin receptors A and B in glomeruli of rats with streptozotocin-induced diabetes at 4, 12, and 24 weeks of age. In addition, streptozotocin-induced rats with diabetes were either treated with 8 to 14 units neutral protamine Hagedorn insulin daily to maintain moderate hyperglycemia (approximately 200 mg/dl) or left untreated to produce severe hyperglycemia (more than 400 mg/dl) during the 4-week study period. The messenger RNA levels for endothelin-1 in glomeruli of diabetic rats increased with the progression of diabetic nephropathy (4 weeks, 2.5 times control level, p < 0.01; 12 weeks, 3.8 times, p < 0.01; and 24 weeks, 5.3 times, p < 0.001. In contrast, messenger RNA levels for endothelin receptors A and B were not altered in glomeruli from diabetic and control rats throughout the experimental period. Messenger RNA for endothelin-3 in glomeruli from diabetic and control rats was not detected until 24 weeks of age. Insulin treatment partially ameliorated the increase in messenger RNA for endothelin-1 in the glomeruli of diabetic rats (0.3 times compared with diabetic rats without insulin treatment, p < 0.01), whereas insulin treatment did not affect messenger RNA for endothelin receptors A and B in diabetic glomeruli. These findings indicate that increased endothelin-1 messenger RNA in glomeruli may be a manifestation of diabetic nephropathy, and hyperglycemia or insulin-deficiency may play a role in abnormal endothelin-1 gene regulation.

[Feelings of well-being and depression in relation to social activity in normal elderly people]

In order to clarify the influence of social activities on the feeling of well-being or depression in the elderly, we studied these relationships in 2 groups with different activities. Group I consisted of 26 subjects (mean age, 77.2 years) living in a retirement house and exposed to relatively few social stimuli. Group II consisted of 47 subjects (mean age, 75.6 years) who were living in their own homes and were confirmed to be socially active. The Morale Scale and the Zung Self-Rating Depression Scale (SDS) were used to evaluate feelings of well-being or depression. The morale scale in group I was significantly lower than in group II. In particular, there was a significant difference in the factor related to aging. The SDS score of group I was significantly higher than that of group II. The depressive state incidence was significantly higher in group I than in group II in all subjects. There was a highly significant correlation between the morale scale score and the SDS score. These results indicate that group I is less satisfied and more depressed than group II. We conclude that social environmental factors are extremely important for the quality of life of elderly people.

Transcriptional activation of matrix genes by transforming growth factor beta 1 in mesangial cells

The accumulation of mesangial matrix is a common histologic abnormality observed over the course of various glomerular diseases. To examine the role of transforming growth factor beta 1 (TGF-beta 1), a well-known regulator of extracellular matrix metabolism, in such processes, we studied the effects of this peptide on the gene expression of extracellular matrix components in cultured rat mesangial cells. TGF-beta 1 increased the mRNA levels for alpha 1 (I) and alpha 1 (IV) collagens and fibronectin. The increase in these mRNA levels was detectable 6 h after stimulation by TGF-beta 1. At 24 h, the mRNA levels for alpha 1 (I) and alpha 1 (IV) collagens and fibronectin increased 1.9-, 2.8- and 2.6-fold, respectively, above their basal levels. Concomitant treatment with cycloheximide did not prevent the stimulation by TGF-beta 1 and resulted in exceptional superinduction for the fibronectin gene. Concomitant treatment with actinomycin D completely inhibited the increase in the mRNA levels induced by TGF-beta 1. Furthermore, TGF-beta 1 showed no stabilizing effect on the transcripts. These results suggest that TGF-beta 1, which is released in glomerular injury, induces an increase in the transcription of the alpha 1 (I) and alpha 1 (IV) collagen and fibronectin genes in mesangial cells and may mediate the accumulation of the extracellular matrix in the mesangium.

[Serum superoxide dismutase (SOD) activity in patients with renal disease by a spintrap method using electron spin resonance (ESR)]

Superoxide dismutase (SOD) activity in serum samples of patients with chronic glomerulonephritis (CGN) and chronic renal failure (CRF) was measured by a spin trap method using electron spin resonance (ESR). Twenty-three patients with CGN, 10 patients with CRF and 10 healthy adults were examined. Among 23 patients with CGN, there were 12 patients with IgA nephropathy and one patient with membranous nephropathy diagnosed by immunofluorescence of renal biopsy specimens. Other CGN patients were diagnosed by its clinical criteria. The serum activity of SOD in patients with CGN or CRF was significantly higher than those in healthy adults (p < 0.05). The serum SOD activity in patients with CRF was also higher than those in patients with CGN (p < 0.05). Marked high levels of serum SOD activity were observed histologically in the advanced stage of IgA nephropathy. These results suggest an increase in serum SOD activity may reflect renal injuries in patients with CGN and CRF.

[A 70-year-old man with right hemiparesis and mutism]

We report a 70-year-old man who had a sudden onset of right hemiparesis and mutism. The lower extremity was more involved than the upper one. He had a long history of diabetes and chronic renal failure for which hemodialysis was necessary. On August 30, 1990, he had an sudden onset of right hemiparesis and mutism. Neurological examination revealed awake but mute in no acute distress. He could only respond to very simple commands such as opening his mouth or protruding his tongue. He did not appear to understand more difficult questions. In addition, he could not answer verbally. He was totally mute. Cranial nerves appeared intact except for slight right central facial paresis and severe diabetic retinopathy. He had complete paralysis of his right leg and a moderate weakness in his right upper extremity. Deep reflexes were diminished in both upper extremities and absent in the lower limbs. Frotal signs such as grasp and snout reflexes were present. Cranial CT scans revealed an ill-defined low density area in the left parasagittal subcortical area and a part of the anterior cerebral artery territory. The supplementary motor area appeared at least in part to be involved. He was treated with glycerol and other supportive cares, however, his clinical course was complicated by pneumonia, heart failure, septicemia, and he expired two months after his stroke. The patient was discussed in a neurological CPC, and the chief discussant arrived at a conclusion that he had an artery-to-artery embolism at the internal carotid bifurcation resulting in the cerebral infarction mainly in the territory of the anterior cerebral artery.(ABSTRACT TRUNCATED AT 250 WORDS)

c-Ha-Ras mutants with point mutations in Gln-Val-Val region have reduced inhibitory activity toward cathepsin B

Protease-inhibitory activity of recombinant Ha-ras gene products (Ras) toward papain and cathepsins B and L was investigated. v-Ha-Ras showed more potent inhibitory activity toward cathepsin B as compared with c-Ha-Ras. We have also investigated protease-inhibitory activity of c-Ha-Ras mutants with point mutations in amino acids between positions 23 and 50. Inhibitory activity of Ras toward papain and cathepsin L was not largely altered among mutants. However, the inhibitory activity toward cathepsin B was significantly impaired by a mutation at position 43, 44, 45 or 48. These results suggest that 43Gln-Val-Val sequence plays an important role at least to inhibit cathepsin B.

Effect of methylprednisolone on transforming growth factor-beta, insulin-like growth factor-I, and basic fibroblast growth factor gene expression in the kidneys of NZB/W F1 mice

The present study was carried out to determine whether transforming growth factor-beta, insulin-like growth factor-I and basic fibroblast growth factor mRNA levels were correlated with disease activity in NZB/W F1 mice, an animal model of systemic lupus erythematosus. Levels of mRNA for these three growth factors increased significantly as nephritis progressed in these mice. At 48 weeks of age, transforming growth factor-beta, insulin-like growth factor-I, and basic fibroblast growth factor mRNA levels showed a 11- (p < 0.001), 10- (p < 0.001), and 8-fold (p < 0.001) increase, respectively, in the renal cortex of NZB/W F1 mice when compared with NZW control mice. In NZW kidneys, these mRNA levels showed little change throughout the study period. At 24 weeks of age, NZB/W F1 mice were divided in 2 groups that received either methylprednisolone or saline injections for 24 weeks. The development of histological lesions and the increase in these growth factor mRNA levels in the kidneys of NZB/W F1 mice were both suppressed by methylprednisolone. These results indicate that the transforming growth factor-beta, insulin-like growth factor and basic fibroblast growth factor may play a role in the progression of murine lupus nephritis and that methylprednisolone may be an effective treatment at the transcription level of these growth factor genes for this type of nephritis.

Cellular and intracellular localization of epsilon-subspecies of protein kinase C in the rat brain; presynaptic localization of the epsilon-subspecies

The cellular and intracellular localization of the epsilon-subspecies of protein kinase C (PKC) in the rat brain was demonstrated by immunocytochemistry using specific antibodies against epsilon-PKC. The epsilon-PKC-specific immunoreactivity was most abundant in the hippocampal formation, olfactory tubercle and Calleja's islands, was moderate in the cerebral cortex, anterior olfactory nuclei, accumbens nucleus, lateral septal nuclei and caudate-putamen and low in the thalamus and medulla. The epsilon-PKC-immunoreactivity was scanty in the perikarya, except for the pyramidal cells of CA3 region of the hippocampus and the immunoreactivity was mainly present in neuropils and nerve fibers. The distribution of epsilon-PKC immunoreactive neurons was consistent with that obtained by in situ hybridization histochemistry. Electron microscopic observations of the hippocampus revealed that the epsilon-PKC is predominantly present in the cytoplasm of axon and nerve terminals and that this enzyme is associated with mitochondrial membrane and vesicles. These results suggested that epsilon-PKC is probably involved in presynaptic functions in CNS, perhaps even neurotransmitter release.

Increased mRNA expression encoding for medullasin in peripheral blood mononuclear cells from patients with IgA nephropathy

We investigated mRNA expression for medullasin (an inflammatory serine protease in bone marrow cells) in peripheral blood mononuclear cells (PBMC) obtained from 36 patients with primary IgA nephropathy (IgAN), 30 patients with other types of primary glomerular disease, 18 patients with secondary IgA nephritis including lupus nephritis and hepatic glomerulosclerosis and 24 healthy age-matched controls. The majority of patients with IgAN (86%) showed elevated medullasin expression in PBMC, while no medullasin mRNA expression was detected in PBMC obtained from patients with other types of primary glomerular disease, secondary IgA nephritis or normal healthy controls. A positive correlation was noted between mRNA levels and urinary protein excretion. The medullasin mRNA expression in PBMC also correlated with the severity of the histopathologic changes in renal tissue obtained from patients with IgAN. All the patients with severe proteinuria (more than 3.0 g/day) showed strong [more than (++)] medullasin mRNA expression in their PBMC. In addition, all the patients with more than (++) medullasin mRNA expression are grade III or IV histopathological findings. These studies suggest that abnormally regulated medullasin gene expression in PBMC may be associated with the progression of primary IgAN.

Effect of monoclonal antibody CD4 on glomerulonephritis of ddY mice, a spontaneous animal model of IgA nephropathy

Immunopathological studies were performed to determine whether the glomerular injuries in ddY mice, a model for IgA nephropathy (Berger's disease), are influenced by treatment with a rat monoclonal antibody (mAb) to murine CD4 molecules. The ddY mice were initially treated with intravenous injections, followed by weekly intraperitoneal injections of mAb CD4. Flow cytometry analysis showed that there was a marked decrease in the number of CD4+ T cells. In immunofluorescence, the mean intensity of IgA deposits in the renal glomerular mesangial areas and capillary walls of the treated ddY mice was significantly lower than that in saline-treated control mice of comparable ages. Glomerular mesangial expansion in the treated mice was milder than that found in the saline control mice. However, no significant differences in the level of serum IgA, urinary protein, and average number of intraglomerular cells between the treated and control ddY mice were observed. Thus, it appears that although CD4+ T cells control the amount of IgA deposits in glomeruli, other factors may be involved in the evolution of IgA nephropathy in ddY mice.

mRNA expression of growth factors in glomeruli from diabetic rats

Evaluations of glomerular mRNA levels encoding for PCNA, TNF-alpha, PDGF-A and -B chains, TGF-beta, IGF-I, bFGF, and EGF were made at 4, 12, and 24 wk after injection of STZ in Sprague-Dawley rats. The mRNA levels for PCNA, TNF-alpha, PDGF-B chain, TGF-beta, and bFGF increased with age in STZ-induced diabetic rats. At 24 wk after STZ injection, mRNA levels for PCNA, TNF-alpha, PDGF-B chain, TGF-beta, and bFGF were increased 3.8-fold, (P < 0.01), 4.2-fold (P < 0.01), 4.0-fold (P < 0.01), 5.2-fold (P < 0.001), and 3.6-fold (P < 0.01), respectively, in the glomeruli of diabetic rats when compared with control rats. In contrast, mRNA levels for IGF-I, PDGF-A chain, and EGF were not altered in glomeruli from diabetic and control rats throughout the experimental period. Insulin treatment partially ameliorated the increase in mRNA levels for PCNA, TNF-alpha, PDGF-B chain, TGF-beta, and bFGF in the glomeruli of diabetic rats. These data indicate that alterations in growth factor mRNA levels in glomeruli may be a manifestation of diabetic nephropathy, and that hyperglycemia or insulin deficiency may play a role in abnormal growth factor gene regulation.

Widening of capillary neck and alteration of extracellular matrix ultrastructure in diabetic rat glomerulus as revealed by computer morphometry and improved tissue processing

Morphological and morphometric studies of glomeruli were carried out in streptozotocin-induced diabetic rats using improved tissue processing and computerized morphometry. Increased mesangial matrix, occupying the enlarged diabetic mesangium, contained an abundance of dark granular material in addition to the microfibrils which were usually found in the control glomeruli. In the diabetic glomeruli, the lamina densa was thick and heterogeneous showing a dense layer both on its epithelial and endothelial aspects, and the lamina rara externa contained more fibrils than in control rats. Detailed estimation of the absolute values of the various compartments of the diabetic glomeruli by using perfusion-fixed materials and a computer-assisted digitizer revealed that the volume and surface area of the mesangium were increased more extensively than those of the capillary; the enlargement of the mesangial-capillary interface area was the most pronounced among the morphometric changes of the diabetic glomeruli; and that the moderate increase in capillary volume was associated with an increased radius. Our quantitative results showed that capillaries in the diabetic glomeruli had an extensively wider neck which may be the first sign of structural damage to the glomerular tuft.

Ultrastructural changes in glomerular epithelial cells in acute puromycin aminonucleoside nephrosis: a study by high-resolution scanning electron microscopy

Ultrastructural changes in the podocytes were studied during the development of, and recovery from, acute puromycin aminonucleoside (PAN) nephrosis using high-resolution scanning electron microscopy (hrSEM) and transmission electron microscopy (TEM). In the process of development of PAN nephrosis, four types of early structural changes were observed before total loss of foot processes: formation of cytoplasmic blebs, masking of filtration clefts, flattening of foot processes, and retraction of foot processes. The masking of filtration clefts visualized by hrSEM corresponded to the multiplication of slit diaphragms and adhesion of foot processes in the TEM findings, and preceded retraction of the foot processes. Changes of podocyte configuration were produced. Recovery from this change of podocyte configuration began as islands of podocyte interdigitation, and was proceeded by expansion of the islands. During recovery, the primary processes were re-established either by retraction or perforation of the thin cytoplasm after the formation of foot processes. We conclude that loss of foot processes begins with the masking of filtration clefts. Recovery from the change in podocyte configuration begins with the formation of new foot processes.

Altered glomerular steady-state levels of tumour necrosis factor-alpha mRNA during nephrotic and sclerotic phases of puromycin aminonucleoside nephrosis in rats

1. We determined glomerular and medullary tumour necrosis factor-alpha mRNA levels in acute puromycin aminonucleoside nephrosis on days 0, 8 and 20. 2. Tumour necrosis factor-alpha mRNA levels were increased fourfold in glomeruli and twofold in the medulla during the nephrotic stage of acute puromycin aminonucleoside nephrosis (day 8). 3. The high tumour necrosis factor-alpha mRNA levels in both glomeruli and the medulla were ameliorated significantly by methylprednisolone administration. 4. Focal glomerular sclerosis was induced in rats by injection of puromycin aminonucleoside on days 0, 27, 34 and 41 and by unilateral nephrectomy on day 22. 5. The percentage of sclerosing glomeruli was 16.6% on day 48 and had increased significantly to 72.8% on day 80. 6. During the sclerotic phase of puromycin amino-nucleoside nephrosis, glomerular tumour necrosis factor-alpha mRNA levels increased as glomerular sclerosis progressed. On day 80, glomerular tumour necrosis factor-alpha mRNA levels were 13-fold higher than levels in control rats. 7. These data suggest that glomerular tumour necrosis factor-alpha mRNA expression is associated with the development of puromycin aminonucleoside-induced glomerular sclerosis.

Low-protein diet attenuates increased gene expression of platelet-derived growth factor and transforming growth factor-beta in experimental glomerular sclerosis

The present study was designed to assess whether platelet-derived growth factor (PDGF)-A and -B chain and transforming growth factor-beta (TGF-beta) mRNA expression in glomeruli are affected by a low-protein (6%) diet during the course of focal glomerulosclerosis (FGS). Puromycin aminonucleoside (PAN) was injected intraperitoneally in rats, and the right kidney was removed on day 22. The nephrotic rats received successive intraperitoneal injections of PAN on days 27, 34, and 41. Control rats were subjected to a sham operation on day 22. The PAN-injected rats were divided into two groups. Group 1 rats were fed a standard diet containing 22% protein, whereas group 2 rats were fed a low-protein diet containing 6% protein, starting on the same day as the first PAN injection. Rats were killed on days 0, 48, 60, and 80 after the initial PAN injection. The percentage of sclerotic glomeruli in group 1 rats increased markedly with time, reaching 73% on day 80. The PDGF-A and -B chain and TGF-beta mRNA levels increased significantly as glomerulosclerosis progressed. A positive correlation was noted between the PDGF and TGF-beta mRNA levels and the incidence of glomerular sclerosis. The low-protein diet reduced the prevalence of glomerular sclerosis (10% on day 80) and attenuated the abnormally high expression of PDGF-A and -B chain and TGF-beta genes in FGS glomeruli. These findings suggest that PDGF and TGF contribute to glomerulosclerosis and that a low-protein diet attenuates markedly the increased glomerular expression of the PDGF and TGF-beta genes in glomerular sclerosis.

Production of hydrogen peroxide by neutrophilic polymorphonuclear leukocytes in patients with diabetic nephropathy

The production of hydrogen peroxide (H2O2) by neutrophilic polymorphonuclear leukocytes (PMN) after stimulation with phorbol myristate acetate (PMA), n-formyl-l-methionyl-l-leucyl-l-phenylalanine (FMLP), aggregated human IgG, or Staphylococcus aureus was determined in 36 patients with non-insulin dependent diabetes mellitus (NIDDM). H2O2 production by PMN after stimulation was measured using flow cytometry. Thirty-six patients with NIDDM were divided into four stages as follows: 1) stage I: non-microalbuminuric stage; 2) stage II: microalbuminuric stage; 3) stage III: proteinuric stage without impairment of renal function; and 4) stage IV: proteinuric stage with impairment of renal function. H2O2 production after PMA stimulation in all stages of NIDDM patients was higher than that in healthy controls. This increase of H2O2 production by PMN was particularly observed in stage IV of NIDDM patients after stimulation. Furthermore, H2O2 production in patients in stage IV was higher than that in patients with non-diabetic disease with impairment of renal function. It appears that reactive oxygen species produced by PMN after stimulation under some conditions may play an important role in the progression of diabetic nephropathy.

Alport syndrome diagnosed by immunofluorescence using a new monoclonal antibody

A 14-year-old female with microscopic hematuria was admitted for a renal biopsy. She had a family history of renal disease without deafness. The findings of light microscopy and conventional immunofluorescence were normal. Electron microscopy showed a diffuse thinning of the glomerular basement membrane (GBM) with its mild splitting. Irregular thickening of GBM and glomerular small dense particles was not observed. Thin basement membrane syndrome was suspected from these findings. However, it was difficult to differentiate from Alport syndrome. Immunofluorescence analysis using the monoclonal antibody to the 28-kilodalton monomers of the noncollagenous domain of type IV collagen verified the diagnosis of heterozygous Alport syndrome.

Growth factor gene expression in kidney of murine polycystic kidney disease

The DBA/2FG-pcy mouse has a form of slowly progressive kidney disease that appears similar in many respects to that seen in the autosomal dominant form of human polycystic kidney disease. The aim of this study was to examine the mRNA expression of growth-related proteins in kidney obtained from DBA/2FG-pcy mice and control DBA/2 mice at 8, 16, and 30 wk of age. The mRNA levels encoding for proliferating cell nuclear antigen (PCNA), transforming growth factor (TGF)-beta, platelet-derived growth factor (PDGF)-A and PDGF-B chains, insulin-like growth factor (IGF)-I, and basic fibroblast growth factor (bFGF) were increased with the progression of cystic lesions in the kidneys of DBA/2FG-pcy mice. At 30 wk of age, mRNA levels of PCNA, TGF-beta, PDGF-A and PDGF-B chains, IGF-I, and bFGF were increased 5.4-fold, 4.8-fold, 4.4-fold, 3.8-fold, 3.7-fold, and 4.6-fold, respectively, compared with those of control DBA/2 mice. In contrast, mRNA levels for epidermal growth factor in kidney of DBA/2FG-pcy mice decreased with age as compared with those of DBA/2 mice. These results suggest that decreased epidermal growth factor mRNA expression and increased expression of PCNA, TGF-beta, PDGF-A and PDGF-B chains, IGF-I, and bFGF mRNA may contribute to the progression of cystic lesions in DBA/2FG-pcy mice.

Increased interleukin 6 mRNA expression by peripheral blood T cells from patients with IgA nephropathy

We investigated interleukin 6 (IL-6) mRNA expression in peripheral blood T-cells obtained from 36 patients with IgA nephropathy (IgAN), 36 patients with other glomerulonephritides and 24 healthy age-matched controls. The majority of patients with IgAN had increased IL-6 mRNA expression by their T cells; no IL-6 mRNA was detected in T cells obtained from patients with other glomerulonephritides or normal controls. A positive correlation was noted between the IL-6 mRNA level and quantity of protein excretion in the urine, histopathological findings, and renal function. However, there was no significant correlation between IL-6 mRNA expression and the IgA-immune complex titer, serum IgA level or blood pressure. mRNA levels in T cells obtained from patients with grade III or IV renal histopathological findings were significantly higher than in those with grade I or II histopathology. In addition, mRNA levels in T cells obtained from patients with more than 1.0 g/day proteinuria were markedly higher than those with less than 1.0 g/day proteinuria. We also studied the clinical course of 11 patients with IgAN during hospitalization. The IL-6 mRNA levels in these patients decreased gradually, as did proteinuria, after treatment. These studies suggest that abnormally regulated IL-6 mRNA expression in peripheral blood T cells may be associated with disease activity in IgAN.

Detection of activated platelets in urinary sediments by immunofluorescence using monoclonal antibody to human platelet GMP-140 in patients with IgA nephropathy

The presence of activated platelets in the urinary sediments was studied by indirect immunofluorescence using monoclonal antigranular membrane protein (GMP)-140 antibody. GMP-140 is generally expressed on the activated-platelets and -vascular endothelial cells. The purpose of the present study was to determine if the presence of activated platelets in the urinary sediments is correlated with glomerular injuries in patients with IgA nephropathy. Fourteen patients with IgA nephropathy and 11 patients with diffuse mesangial proliferative glomerulonephritis without glomerular IgA deposition (PGN) were examined. The number of activated platelets in the urinary sediments was markedly increased in patients in the advanced stage of IgA nephropathy. The ratio of activated platelets to total platelets in the urinary sediments was also increased in such patients. It appears that the detection of activated platelets in the urinary sediments is useful in determining the degree of histological changes in IgA nephropathy.

Messenger RNA expression for growth factors in glomeruli from focal glomerular sclerosis

Focal glomerular sclerosis was induced in rats by chronic injections of puromycin aminonucleoside (PAN) on Days 0, 27, 34, and 41 and by unilateral nephrectomy on Day 22. Rats were sacrificed on Days 0, 8, and 20 (acute phase) and on Days 48, 60, and 80 (sclerotic phase). The percentage of sclerosing glomeruli was 16.6% on Day 48 and increased significantly to 72.8% on Day 80. We examined glomerular mRNA levels for proliferating cell nuclear antigen (PCNA), platelet-derived growth factor (PDGF)-A and B chains, transforming growth factor (TGF)-beta, epidermal growth factor (EGF), insulin-like growth factor (IGF)-I, and basic fibroblast growth factor (bFGF) on Days 0, 8, 20, 48, 60, and 80. Although these growth factor mRNA levels showed little change in glomeruli until Day 20, all growth factor mRNA levels increased in glomeruli during the sclerotic phase of PAN nephrosis as glomerular sclerosis progressed. On Day 80, mRNA levels for PCNA, PDGF-A and B chains, TGF-beta, EGF, IGF-I, and bFGF increased 12-, 10-, 12-, 15-, 2-, 2-, and 8-fold, respectively, in the glomeruli of PAN-treated rats with marked glomerular sclerosis when compared with control rats. Unilateral nephrectomy without PAN administration did not cause glomerular sclerosis up to Day 80 and mRNA levels for PCNA, PDGF-A and -B chains, TGF-beta, EGF, IGF-I, and bFGF in this group were almost the same as those in the normal sham-operated group. These data suggest that changes in growth factor mRNA levels in glomeruli may contribute to the development of PAN-induced glomerular sclerosis.

Extracellular matrix component mRNA expression in glomeruli in experimental focal glomerulosclerosis

This study was designed to assess how the expression of genes for components of the extracellular matrix is altered in a model of focal glomerular sclerosis. In this model, a unilateral nephrectomy combined with injections of puromycin aminonucleoside induces a much higher incidence of focal glomerular sclerosis. Rats received puromycin aminonucleoside on days 0, 27, 34, and 41 and underwent unilateral nephrectomy on day 22. Control rats received physiologic saline injections with and without unilateral nephrectomy. Rats from each group were killed on days 48, 60, and 80. The steady-state levels of glomerular mRNA encoding type IV collagen, the B1 and B2 chains of laminin, heparan sulfate proteoglycan, and type I and type III collagens were compared in both the puromycin aminonucleoside-treated and the control glomeruli. The mRNA levels encoding type IV collagen and laminin B1 and B2 were increased three-, two-, and twofold, respectively, on day 48 of focal glomerular sclerosis. These transcripts were further increased eight-, seven-, and eightfold, respectively, on day 80 compared with the control glomeruli (P < 0.01). In contrast, heparan sulfate proteoglycan mRNA levels were not increased on day 48 when the animals had marked proteinuria. However, the heparan sulfate proteoglycan mRNA levels did become elevated by day 60 and remained elevated thereafter. The expression of type I and type III collagen mRNA was increased 12- and 7-fold, respectively (P < 0.01), on day 80 in focal glomerular sclerosis rats compared with the controls. An immunofluorescence study revealed the accumulation of immunoglobulin M, C3, type IV collagen, laminin, heparan sulfate proteoglycan, and type I and type III collagens in the sclerotic area. These data indicate that changes in the mRNA levels for components of the basement membrane and interstitial collagen are associated with the development of glomerular sclerosis.