Early critical cortical infarction by anti-angiotensin II type 1 receptor antibody: A case report and literature review.

RATIONALE: Anti-angiotensin II type 1 receptor antibodies (AT1R-Abs) have been demonstrated to increase the risk of antibody-mediated rejection. We report a case of AT1R-Ab mediated rejection which caused early critical cortical infarction. PATIENT CONCERNS: A 52-year-old man with end-stage kidney disease underwent preemptive kidney transplantation (KT) from his wife. He had no immunologic risk except ABO incompatibility. Proper desensitization treatment were applied prior to KT. On postoperative day 1, he showed stable clinical course with adequate urine output, but there was no decrease in serum creatinine level and imaging studies showed hypoperfusion in the transplanted kidney. DIAGNOSES: Allograft biopsy revealed total cortical infarction with severe necrotizing vasculitis, but the medullary area was preserved. Serum AT1R-Ab concentration was elevated from 10.9 U/mL before KT to 19.1 U/mL on 7 days after KT. INTERVENTIONS: He was treated with plasmapheresis, intravenous immunoglobulin, rituximab, high-dose methylprednisolone, and bortezomib. OUTCOMES: The treatment showed a partial response, and he was discharged with 7.3 mg/dL creatinine level. At 4 months, his creatinine plateaued at 5.5 mg/dL and AT1R-Ab decreased to 3.6 U/mL. LESSONS: This case highlights the risk of early active antibody-mediated rejection by preformed AT1R-Ab, suggesting its ability to exhibit atypical histopathologic findings, such as total cortical infarction.

Comparison of the renal cortex and the medulla for antibody mediated rejection.

OBJECTIVES: The presence of the peritubular capillaritis and its extent are important for diagnosis of the antibody-mediated rejection in kidneys. However, it is recommended that peritubular capillaritis should only be scored in the cortex. This study aims to focus on peritubular capillaritis scoring both in the cortex and the medulla to understand the value of the medulla in the diagnosis of antibody-mediated rejection. METHODS: Fifty-one allograft renal biopsy were re-evaluated for peritubular capillaritis, C4d and acute tubular injury, separately for the cortex and the medulla according to the Banff. RESULTS: Seventeen cases (33.3%) had peritubular capillaritis both in the cortex and the medulla and three (5.9%) cases had peritubular capillaritis only in the cortex while five (9.8%) cases had only in the medulla. Eighteen (35%) of the cases had C4d staining both in the cortex and the medulla and 14 (27.5%) cases had C4d positivity only in the cortex and 18 (35.3%) cases only in the medulla. Twenty-three (45%) cases had acute tubular injury both in the cortex and the medulla and 31 (60.7%) cases had acute tubular injury only in the cortex and 23 (45.1%) cases had only in the medulla. The sensitivity, specificity, positive and negative predictive values of medullar peritubular capillaritis predicting cortical peritubular capillaritis were 85.7%, 86.7%, 81.8% and 89.7%, respectively. CONCLUSION: In case of absence of the cortical tissue, medulla can be used as a reference for antibody-mediated rejection considering the morphological features, results of donor-specific antibody and renal function tests.

Upregulation of endothelial cell adhesion molecules characterizes veins close to granulomatous infiltrates in the renal cortex of cats with feline infectious peritonitis and is indirectly triggered by feline infectious peritonitis virus-infected monocytes in vitro.

One of the most characteristic pathological changes in cats that have succumbed to feline infectious peritonitis (FIP) is a multifocal granulomatous phlebitis. Although it is now well established that leukocyte extravasation elicits the inflammation typically associated with FIP lesions, relatively few studies have aimed at elucidating this key pathogenic event. The upregulation of adhesion molecules on the endothelium is a prerequisite for stable leukocyte-endothelial cell (EC) adhesion that necessarily precedes leukocyte diapedesis. Therefore, the present work focused on the expression of the EC adhesion molecules and possible triggers of EC activation during the development of FIP. Immunofluorescence analysis revealed that the endothelial expression of P-selectin, E-selectin, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) was elevated in veins close to granulomatous infiltrates in the renal cortex of FIP patients compared to non-infiltrated regions and specimens from healthy cats. Next, we showed that feline venous ECs become activated when exposed to supernatant from feline infectious peritonitis virus (FIPV)-infected monocytes, as indicated by increased adhesion molecule expression. Active viral replication seemed to be required to induce the EC-stimulating activity in monocytes. Finally, adhesion assays revealed an increased adhesion of naive monocytes to ECs treated with supernatant from FIPV-infected monocytes. Taken together, our results strongly indicate that FIPV activates ECs to increase monocyte adhesion by an indirect route, in which proinflammatory factors released from virus-infected monocytes act as key intermediates.

Deficiency of T-regulatory cells exaggerates angiotensin II-induced microvascular injury by enhancing immune responses.

AIMS: T-regulatory lymphocyte (Treg) adoptive transfer prevented angiotensin (Ang) II-induced hypertension and microvascular injury. Scurfy mice are deficient in Treg because of a mutation in the transcription factor forkhead box P3 (Foxp3) gene. Enhanced Ang II effects in the absence of Treg would unambiguously demonstrate their vascular protective role. We hypothesized that adoptive transfer of Scurfy vs. wild-type T cells will exacerbate Ang II-induced microvascular damage in T and B-cell-deficient recombination-activating gene 1 (Rag1) knockout mice. METHODS AND RESULTS: Rag1 knockout mice were injected with vehicle, 10(7) T cells from wild-type or Scurfy mice or 10 (6)wild-type Treg alone or in combination with Scurfy T cells, and then infused or not with Ang II (490 ng/kg per min, subcutaneous) for 14 days. Ang II increased SBP in all the groups, but DBP only in wild-type and Scurfy T-cell groups. Ang II-induced endothelial dysfunction and oxidative stress in perivascular adipose tissue (PVAT) of mesenteric arteries of the wild-type T-cell group, whereas these were exaggerated in the Scurfy T-cell group. Ang II enhanced microvascular remodeling and stiffness in vehicle and Scurfy T-cell groups. Ang II increased monocyte chemotactic protein-1 expression in the vascular wall and PVAT, monocyte/macrophage infiltration and proinflammatory polarization in PVAT and the renal cortex, and T-cell infiltration in the renal cortex only in the Scurfy T-cell group. Treg coinjection in the vehicle and Scurfy T-cell groups prevented or reduced the effects of Ang II. CONCLUSION: FOXP3+ Treg deficiency exaggerates Ang II-induced microvascular injury by modulating innate and adaptive immune responses.

Adoptive transfer of bone marrow dendritic cells failed to localize in the renal cortex and to improve renal injury in adriamycin nephropathy.

BACKGROUND AND AIMS: Murine bone marrow (BM) dendritic cells (DCs) can be modulated to be tolerogenic by cytokines, such as interleukin (IL)-10 and transforming growth factor (TGF)-ß, and may play a regulatory role and sustain immune hemostasis in cognate kidney disease. However, it is unknown whether BM-DCs can be used to protect against renal injury in murine Adriamycin nephropathy (AN). METHODS: In this study, by adoptive in vivo transfer of BM-DCs, including immature DCs, mature DCs (lipopolysaccharide-stimulated DCs) and BM regulatory DCs (IL-10/TGF-ß-modified DCs, DCregs), we addressed the potential benefits of BM-DCs in chronic kidney disease. RESULTS: We found that after adoptive transfer of DCregs, renal injury, including glomerulosclerosis, interstitial fibrosis and tubular atrophy, was not changed compared to AN controls. Correspondingly, renal functions measured by serum creatinine, 12-hour urine protein and creatinine clearance were also not improved by transfusion with DCregs compared to AN controls. CONCLUSION: This study showed that the adoptive transfer of BM-DCs was unable to improve renal injury in an AN model, and this failure related to their inability to access the kidney.

The protective effects of DA-9801 (Dioscorea extract) on the peripheral nerves in streptozotocin-induced diabetic rats.

It has been reported that DA-9801, an extract mixture of Dioscorea japonica Thunb and Dioscorea nipponica Makino, produces a neurotrophic activity. Therefore, this study was conducted to examine the neuroprotective effects of DA-9801 in streptozotocin-induced diabetic rats. The experimental rats were divided into six groups: the control group, Group I (non-diabetic rats treated with DA-9801), Group II (diabetic, non-treated rats) and Groups III, IV, and V (diabetic rats treated with DA-9801 at doses of 10, 50 or 100 mg/kg/d). Following a 16-wk course of oral treatment with DA-9801, functional parameters (von Frey filament test, hot plate test), biochemical parameters (nerve growth factor (NGF), tumor necrosis factor (TNF)-α, interleukin (IL)-6) were measured. An immunohistochemical staining was done to assess the neuroprotective effects of DA-9081 in the skin, sciatic nerve, gastric mucosa and renal cortex. In Week 8, pain was evoked by either tactile or thermal stimuli, whose threshold was significantly higher in Group III, IV and V than Group II. Western blot analysis showed a more significant increase in NGF and decrease in TNF-α and IL-6 in Group III, IV and V than in Group II (p<0.05). Moreover, following the treatment with DA-9801, a loss of intraepidermal nerve fibers (IENFs) was inhibited to a significant level in the skin, myelinated axonal fibers of the sciatic nerve and small nerve fibers innervating the gastric mucosa or renal cortex (p<0.05). Our results demonstrated that DA-9801 is a beneficial agent that protects the peripheral nerves in diabetic rats.

Induction of passive Heymann nephritis in complement component 6-deficient PVG rats.

Passive Heymann nephritis (PHN), a model of human membranous nephritis, is induced in susceptible rat strains by injection of heterologous antisera to rat renal tubular Ag extract. PHN is currently considered the archetypal complement-dependent form of nephritis, with the proteinuria resulting from sublytic glomerular epithelial cell injury induced by the complement membrane attack complex (MAC) of C5b-9. This study examined whether C6 and MAC are essential to the development of proteinuria in PHN by comparing the effect of injection of anti-Fx1A antisera into PVG rats deficient in C6 (PVG/C6(-)) and normal PVG rats (PVG/c). PVG/c and PVG/C6(-) rats developed similar levels of proteinuria at 3, 7, 14, and 28 days following injection of antisera. Isolated whole glomeruli showed similar deposition of rat Ig and C3 staining in PVG/c and PVG/C6(-) rats. C9 deposition was abundant in PVG/c but was not detected in PVG/C6(-) glomeruli, indicating C5b-9/MAC had not formed in PVG/C6(-) rats. There was also no difference in the glomerular cellular infiltrate of T cells and macrophages nor the size of glomerular basement membrane deposits measured on electron micrographs. To examine whether T cells effect injury, rats were depleted of CD8+ T cells which did not affect proteinuria in the early heterologous phase but prevented the increase in proteinuria associated with the later autologous phase. These studies showed proteinuria in PHN occurs without MAC and that other mechanisms, such as immune complex size, early complement components, CD4+ and CD8+ T cells, disrupt glomerular integrity and lead to proteinuria.

TNF-alpha neutralization ameliorates obstruction-induced renal fibrosis and dysfunction.

Upper urinary tract obstruction results in tubulointerstitial fibrosis and a progressive decline in renal function. Although several inflammatory mediators have been implicated in the pathophysiology of renal obstruction, the contribution of TNF-alpha to obstruction-induced fibrosis and renal dysfunction has not been thoroughly evaluated. To study this, male Sprague-Dawley rats were subjected to left unilateral ureteral obstruction vs. sham operation. Rats received either vehicle or a pegylated form of soluble TNF receptor type 1 (PEG-sTNFR1) every 84 h. The kidneys were harvested 1, 3, or 7 days postoperatively, and tissue samples were analyzed for TNF-alpha expression (ELISA), macrophage infiltration (ED-1 staining), transforming growth factor-beta(1) expression (ELISA, RT-PCR), collagen I and IV activity (Western Blot, immunohistochemistry), alpha-smooth muscle actin accumulation (immunohistochemistry, Western blot analysis), and angiotensinogen expression (Western blot). In a separate arm, the glomerular filtration rate (inulin clearance) of rats subjected to unilateral ureteral obstruction in the presence of either vehicle or PEG-sTNFR1 was determined. Renal obstruction induced increased tissue TNF-alpha and transforming growth factor-beta(1) levels, collagen I and IV activity, interstitial volume, alpha-smooth muscle actin accumulation, angiotensinogen expression, and renal dysfunction, whereas treatment with PEG-sTNFR1 significantly reduced each of these markers of renal fibrosis. These results demonstrate that TNF-alpha mediates obstruction-induced renal fibrosis and identify TNF-alpha neutralization as a potential therapeutic option for the amelioration of obstruction-induced renal injury.

Total hepatic ischemia and reperfusion after state controlled hemorrhagic shock, with used of different solutions: effects of neutrophils sequestration in kidney of rats

OBJETIVO: Avaliar e comparar o seqüestro de neutrófilos no rim de rato, como efeito da isquemia e reperfusão hepática total após estado de choque hemorrágico controlado, com uso de diferentes soluções eletrolíticas.MÉTODOS: Utilizou-se 18 ratos Wistar, machos, adultos, divididos em três grupos conforme a solução utilizada para reanimação: Grupo SF: solução fisiológica; Grupo SH: solução hipertônica de NaCl a 7,5% seguido pela solução de ringer com lactato; Grupo RL: solução de ringer com lactato. Todos os animais foram submetidos à sangria controlada até pressão arterial média (PAM) atingir 40 mmHg, permanecendo por 20 minutos. Realizou-se reanimação volêmica até PAM=80 mmHg com a solução conforme o grupo estudado. Em seguida realizou-se uma laparotomia e a manobra de Pringle por 15 minutos. Os animais foram acompanhados até duas horas. Para comparações estatísticas entre as contagens de neutrófilos, no interstício do córtex renal, foram efetuados os testes ANOVA e a análise de covariância, ajustando-se para o tempo de sobrevida. Os parâmetros hemodinâmicos avaliados foram: PAM, freqüência cardíaca, índice cardíaco, índice de resistência vascular sistêmica. As variáveis metabólicas analisadas foram: pH, bicarbonato, reserva de base e lactato, além de eletrólitos. RESULTADOS: Os valores médios de tempo de sobrevida, em minutos, por grupo foram: Grupo SF 79,0±12,0; Grupo RL 97,0±11,0; Grupo SH 67,0±10. Os valores médios da contagem de neutrófilos/campo no córtex renal foram: Grupo SF 0,55±0,68; Grupo RL 1,68±0,53; Grupo SH 1,33±0,43. E quando são ajustados para o tempo de sobrevida encontram-se: Grupo SF 0,55; Grupo RL 1,62; Grupo SH 1,39. Houve diferença estatisticamente significativa, na contagem de neutrófilo entre o Grupo SF com os demais, usando-se ou não o ajuste pelo tempo de sobrevida (p=0,016 e p=0,0128). CONCLUSAO: As duas situações críticas, choque hemorrágico controlado e manobra de Pringle, promoveram seqüestro de neutrófilos no interstício renal do rato, sendo a solução fisiológica com a menor média, diferenciando estatisticamente das demais soluções, neste modelo.

Nuclear factor kappaB activity determines the sensitivity of kidney epithelial cells to apoptosis: implications for mercury-induced renal failure.

Nuclear factor kappa B (NF-kappaB) is a thiol-dependent transcriptional factor that promotes cell survival and protects cells from apoptotic stimuli. Numerous studies have demonstrated increased sensitivity to apoptosis associated with inhibition of NF-kappaB activation in various cell types. We have previously demonstrated that mercuric ion (Hg(2+)), one of the strongest thiol-binding agents known, impairs NF-kappaB activation and DNA binding at low microM concentrations in kidney epithelial cells. In the present studies we investigated the hypothesis that inhibition of NF-kappaB activation by Hg(2+) and other selective NF-kappaB inhibitors would increase the sensitivity of kidney epithelial (NRK52E) cells to apoptogenic agents to which these cells are normally resistant. Fewer than 10% of untreated cells in culture were found to be apoptotic when evaluated by DNA fragmentation (TUNEL) assay. Treatment of cells with Hg(2+) in concentrations up to 5 microM or with tumor necrosis factor-alpha (TNF) (300 units/ml) did not significantly increase the proportion of apoptotic cells, compared with untreated controls. However, when TNF was given following Hg(2+) pretreatment (0.5 to 5 microM for 30 min), the proportion of cells undergoing apoptosis increased by 2- to 6-fold over that seen in untreated controls. Kidney cells pretreated with specific NF-kappaB inhibitors (Bay11-7082 or SN50) prior to TNF also showed a significant increase in apoptosis. Increased sensitivity to apoptotic cell death following these treatments was significantly attenuated in cells transfected with a p65 expression vector. In studies in vivo, rats pretreated by intraperitoneal injection with Hg(2+) (0.75 mg/kg) 18 h prior to administration of bacterial lipopolysaccharide (LPS) (10 mg/kg) displayed impaired NF-kappaB activation and an increased mitochondrial cytochrome c release in kidney cortical cells. These findings are consistent with the view that prevention of NF-kappaB activity in vitro or in vivo enhances the sensitivity of kidney cells to apoptotic stimuli to which these cells are otherwise resistant. Since apoptosis is known to play a seminal role in the pathogenesis of renal failure caused by toxicant injury to tubular cells, the present findings suggest that inhibition of NF-kappaB activity may define a molecular mechanism underlying the pathogenesis of Hg(2+) toxicity in kidney cells.

Fibroblasts and antigen-presenting cells in the renal interstitium of streptozotocin-induced diabetic rats on a high cholesterol diet.

The cortical peritubular interstitium of the normal kidney contains both fibroblasts and antigen-presenting dendritic cells. Characteristics of these interstitial cells were analyzed in an overnutrition model by electron microscopy after the cold-dehydration technique and immunohistochemistry for antigen-presenting cells. In control rats, fibroblasts and dendritic cells were clearly identified by electron microscopy on the basis of their distinct ultrastructures. Fibroblasts possessed slender cell processes, and contained an abundance of actin filament bundles occasionally anchoring to surrounding structures, whereas dendritic cells possessed irregularly-shaped cell processes with a clear cytoplasm and a paucity of actin filament bundles. In the experimental kidney from diabetic rats given a high cholesterol diet, the peritubular interstitium contained fibroblasts and vacuolated cells, and the extracellular matrices such as collagen bundles were distinctly increased compared with the control rat kidney. Immunohistochemical staining with OX6 and ED1 revealed that the peritubular interstitium in the control rat kidney contained dendritic cells, while that in the experimental rats was occupied by macrophages. The present study provides the first evidence indicating that overnutrition may dramatically affect the immune cells in nonlymphoid tissue.

Expression of the progesterone receptor and progesterone- metabolising enzymes in the female and male human kidney.

Due to high binding affinity of progesterone to the human mineralocorticoid receptor (hMR), progesterone competes with the natural ligand aldosterone. In order to analyse how homeostasis can be maintained by mineralocorticoid function of aldosterone at the MR, especially in the presence of elevated progesterone concentrations during the luteal phase and pregnancy, we investigated protective mechanisms such as the decrease of free progesterone by additional binding sites and progesterone metabolism in renal cells. As a prerequisite for sequestration of progesterone by binding to the human progesterone receptor (hPR) we demonstrated the existence of hPR expression in female and male kidney cortex and medulla at the level of transcription and translation. We identified hPR RNA by sequencing the RT-PCR product and characterised the receptor by ligand binding and scatchard plot analysis. The localisation of renal hPR was shown predominantly in individual epithelial cells of distal tubules by immunohistology, and the isoform hPR-B was detected by Western blot analysis. As a precondition for renal progesterone metabolism, we investigated the expression of steroid-metabolising enzymes for conversion of progesterone to metabolites with lower affinity to the hMR. We identified the enzyme 17alpha-hydroxylase for renal 17alpha-hydroxylation of progesterone. For 20alpha-reduction, different hydroxysteroid dehydrogenases (HSDs) such as 20alpha-HSD, 17beta-HSD type 5 (3alpha-HSD type 2) and 3alpha-HSD type 3 were found. Further, we detected the expression of 3beta-HSD type 2 for 3beta-reduction, 5alpha-reductase (Red) type 1 for 5alpha-reduction, and 5beta-Red for 5beta-reduction of progesterone in the human kidney. Therefore metabolism of progesterone and/or binding to hPR could reduce competition with aldosterone at the MR and enable the mineralocorticoid function.

MCP-1 and RANTES are expressed in renal cortex of rats chronically treated with nitric oxide synthase inhibitor. Involvement in macrophage and monocyte recruitment.

Long-term inhibition of nitric oxide synthase (NOS) in rats is known to cause systemic hypertension and renal parenchymal injury. We have previously reported that activation of intra-renal renin-angiotensin system was a major contributing factor for renal injury in chronically NOS-inhibited rats. Massive interstitial infiltration of monocytes/macrophages (M/M) was characteristically seen in this model. The present study was performed to elucidate the role of chemokines, RANTES and MCP-1, in promoting M/M recruitment into the renal cortex. The number of infiltrating ED-1-positive cells was examined in association with the level of expression of RANTES and MCP1 mRNAs in the renal cortex of rats treated orally for 12 weeks with L-NAME. Compared to controls rats, the number of infiltrating ED-1-positive cells was significantly higher in L-NAME-treated rats. The mRNA expressions of both RANTES and MCP-1 were significantly higher in L-NAME-treated rats than the control. In L-NAME-treated rats, the high number of ED-1-positive cells and increased expression of both RANTES and MCP-1 were suppressed by ACE inhibitor, but not by hydralazine. In contrast, neither ED-1 counts nor RANTES mRNA expression were affected by angiotensin (Ang) II type 1 receptor antagonist. These results suggest the likely involvement of RANTES and MCP-1 in the recruitment of M/M into the renal cortex of rats with chronic NOS inhibition. Furthermore, it is also indicated that Ang II stimulates MCP-1 expression via Ang II type 1 receptor, whereas RANTES expression is mediated via Ang II type 2 receptor.

Cortical fibroblast culture from human biopsies.

BACKGROUND: Tubulointerstitial fibrosis is an integral part of progressive renal disease. Human cortical fibroblasts are believed to be key effector cells in fibrogenesis. Thus, a reliable culture of these cells is necessary for studies of their pathophysiology. METHODS: Cortical fibroblast culture from routine kidney biopsies were analyzed and the cells were characterized. Indirect immunofluorescence staining was done after the first passage for cytokeratin, vimentin, alpha-smooth muscle actin, CD 44, CD 54, CD 68, collagen types I, III, and HLA-DR. We then assessed the utility of the putative fibroblast markers CD 90, prolyl-4-hydroxylase (P4H) and F1b in simultaneous stainings of tubular epithelial cells. RESULTS: During the study period, 49 biopsy cores were cultured and cortical fibroblasts could be successfully established in 21 cases (42.9%). There was no relation between the success rate of culture and the degree of interstitial fibrosis, but an association was seen with the time of completion of the first passage. There was a negative correlation between the extent of scarring and the percentage of cytokeratin positive cells (r = -0.66, p < 0.001). All primary fibroblasts were negative for factor VIII, HLA-DR, CD 68, and cytokeratin. They expressed alpha-smooth muscle actin and collagen types I and III to variable degrees. There was a robust correlation between the percentage of alpha-smooth muscle actin positive cells and interstitial scarring but no such association with collagen type I or type III positive cells. The three putative fibroblast markers did not prove useful in differentiating between tubular epithelial cells and fibroblasts. However, since only fibroblasts stained positive for CD 90 and negative for cytokeratin, these two markers may suffice to distinguish fibroblasts from other renal cellular elements. CONCLUSIONS: Cortical renal fibroblasts can be easily cultured from kidney biopsy cores, though the success rate of pure cultures is below 50%. Staining for CD 90 and cytokeratin may suffice for initial characterization of these cells.

Autoantibodies against the angiotensin receptor (AT1) in patients with hypertension.

Sera from patients with malignant essential hypertension (n = 14), malignant secondary hypertension mainly attributable to renovascular diseases (n = 12) and renovascular diseases without malignant hypertension (n = 11) and from normotensive healthy blood donors (n = 35) were studied for the presence of autoantibodies against G-protein-coupled cardiovascular receptors. Autoantibodies against the angiotensin II receptor (AT1) were detected in 14, 33, 18 and 14% of patients with malignant essential hypertension, malignant secondary hypertension, renovascular diseases and control patients, respectively. Sensitivity of the enzyme immunoassay was assessed as 5 microg/ml IgG. Patients did not show antibodies against bradykinin (B2) or angiotensin II subtype 2 (AT2) receptors. Autoantibodies affinity-purified from positive patients localized AT receptors in Chinese hamster ovary transfected cells, and displayed a positive chronotropic effect on cultured neonatal rat cardiomyocytes. These results demonstrate the existence of autoantibodies against a functional extracellular domain of human AT1 receptors in patients with malignant hypertension, and suggest that these autoantibodies might be involved in the pathogenesis of malignant hypertension.

Interleukin-8 secretion of cortical tubular epithelial cells is directed to the basolateral environment and is not enhanced by apical exposure to Escherichia coli.

In upper urinary tract infections, tubular epithelial cells (TEC) may play a pivotal role in the initiation of the renal inflammatory response. They exert crucial immunological functions such as processing and presentation of foreign antigen, secretion of proinflammatory cytokines (interleukin-6 [IL-6] and tumor necrosis factor alpha) and chemokines (IL-8, MCP-1, ENA-78, and RANTES). Since monolayer cultures are a limited model for polarized tubular epithelial cells, we studied the side-dependent IL-8 secretion of TEC by using cell culture inserts as a basement membrane imitation. Primary cultures of proximal TEC were stimulated with differently fimbriated mutants of Escherichia coli, E. coli LPS, S-fimbria isolates, and IL-1alpha. IL-8 protein was measured by enzyme-linked immunosorbent assay, and IL-8-like biological activity was tested by measuring elastase release from polymorphonuclear cells in supernatants of the upper and lower compartments. IL-8 mRNA was compared by competitive PCR. IL-8 secretion by TEC into the basolateral environment was significantly higher than secretion into the apical compartment, representing the tubular lumen. However, stimulation of IL-8 secretion by TEC was restricted to IL-1alpha and was not inducible by E. coli mutants, S fimbriae, or lipopolysaccharide. With this in vitro model of polarized TEC, we show that luminal contact of TEC with uropathogenic E. coli does not result in enhanced IL-8 secretion. The basolaterally directed production of the neutrophil chemotactic factor IL-8 by TEC after stimulation with IL-1alpha might play an important role in the initiation of inflammatory cell influx into the renal parenchyma.

Cortical benign fibromatous tumor (fibroma) of the kidney.

Benign fibromatous tumor (BFT), also named 'fibroma', is a distinctive clinico-pathologic entity occurring in epididymis, spermatic cord, paratesticular structures, testis, renal peripelvis and rarely in renal parenchyma. We report the first case of a BFT (fibroma) located in the cortex of the kidney, and a critical review on the topic is provided. Tumor was found incidentally at autopsy as a small cortical nodule. With the increasing use of radiological imaging of the abdomen, it is likely that an increased number of incidental and asymptomatic benign renal tumors will be diagnosed. We underline that BFT (fibroma) should be considered in the preoperative differential diagnosis of renal cortical nodules.

Glomerular overexpression and increased tyrosine phosphorylation of focal adhesion kinase p125FAK in lupus-prone MRL/MP-lpr/lpr mice.

Much progress has been made in understanding how mammalian cells receive a diverse array of external stimuli and convert them into intracellular biochemical signals. Such efforts have identified a large number of signalling molecules. However, our knowledge is limited as to their pathophysiological role in particular diseases. We demonstrate herein that an integrin-linked signalling molecule, focal adhesion kinase p125FAK (FAK), is overexpressed in glomeruli of lupus-prone MRL/MP-lpr/lpr (MRL-lpr) mouse as compared to its congeneic MRL-+/+ strain. Increased expression was specifically demonstrated in glomeruli but not in other tissues examined. The overexpression was observed in 16-week-old MRL-lpr mice with active nephritis, as well as in younger animals at 4 weeks of age. Thus, the upregulation of FAK clearly preceded the clinical onset of nephritis. FAK in MRL-lpr glomeruli is highly tyrosine phosphorylated and is associated with adapter protein Grb2. Previous in vitro studies have shown that the association of FAK/Grb2 links cell adhesion to the Ras pathway, which ultimately stimulates mitogen-activated protein (MAP) kinase, an important regulator of cell proliferation. In accordance, we observed constitutive MAP kinase activation in MRL-lpr glomeruli. Our findings suggest that signalling pathways involving FAK are activated in MRL-lpr glomeruli, and are likely to play a role in the development and progression of autoimmune-mediated murine nephritis.

Mycophenolate mofetil prevents the induction of active Heymann nephritis: association with Th2 cytokine inhibition.

The effect of mycophenolate mofetil (MMF) was examined in active Heymann nephritis (HN), an animal model of human membranous nephropathy. HN was induced in Lewis rats with Fx1A/complete Freund's adjuvant (CFA), and controls only received CFA. The induction of HN was prevented by MMF (30 mg/kg per d) from 0 to 4 wk after immunization. Proteinuria was not different in CFA controls up to 16 wk, and was significantly less than in untreated HN from 6 wk onward. Serum anti-Fx1A antibody (Ab) levels and glomerular Ig deposition were suppressed during therapy. The interstitial infiltrate of alphabetaTCR+, CD4+ and CD8+ T cells, natural killer cells, and macrophages (mphi) observed in untreated HN at 8 wk was absent from rats treated from 0 to 4 wk with MMF. Semiquantitative reverse transcription-PCR for renal mononuclear cell cytokine mRNA at 8 wk demonstrated that MMF from 0 to 4 wk prevented the increased expression of Th1 (interferon-gamma, lymphotoxin), Th2 (interleukin-4), and mphi (tumor necrosis factor-alpha) cytokines identified in untreated HN. In lymph node draining sites of immunization, MMF limited both enlargement and the increased proportion of CD3+, CD4+, and CD8+ T cells observed in untreated HN and CFA controls. MMF suppressed Th2 (interleukin-4) but not Th1 (interferon-gamma, lymphotoxin) cytokine mRNA expression in lymph nodes. MMF from 4 to 8, 6 to 12, or 10 to 14 wk did not prevent proteinuria, serum anti-Fx1A Ab, or glomerular IgG deposition when compared with untreated HN. This study showed that MMF from 0 to 4 wk prevented the induction of HN and was associated with preferential suppression of Th2 cytokines. This therapy may prove useful in human idiopathic membranous nephropathy.

Cytokine production in primary histoculture by human normal kidney, renal cell carcinoma and benign renal angiomyolipoma tissues.

In order to understand the ability of normal human kidney, benign renal angiomyolipoma and malignant renal cell carcinoma (RCC) cells to produce cytokines, we determined the IL-1-beta, IL-6, IL-10, IL-11, TNF-alpha and TGF-beta-1 concentration in the supernatant of histoculture specimens according to thymidine labelling indices. From these studies, we conclude that normal, benign and malignant renal tissues are one of the main sources of IL-6 production and patterns of IL-6 production are inversely proportional to thymidine labelling index in normal kidney(r = -0.9). However, IL-6 production is increased in proportion to the increasing thymidine labelling index in benign or malignant tissues (r = 0.94, r = 0.76). There is no production of IL-1-beta, IL-10, IL-11, TNF-alpha or TGF-beta-1. These findings allows many important studies of cytokines in normal, benign and malignant renal disease. Patterns of IL-6 production are different in normal and benign or malignant changed renal disease. There is no overlapping biologic effects among IL-6, IL-1-beta and TNF-alpha. Histoculture supports future studies of these cytokines.