Up-regulation of monocyte chemoattractant protein-1 in tubulointerstitial lesions of human diabetic nephropathy

BACKGROUND: We previously described that monocyte chemoattractant protein-1 (MCP-1) plays an important role in progressive glomerular and interstitial damage in inflammatory renal diseases. However, the expression of MCP-1 in diabetic nephropathy remains to be investigated. METHODS: We examined whether locally expressed MCP-1 participates in human diabetic nephropathy via recruiting and activating monocytes/macrophages (Mphi). Urinary and serum MCP-1 levels were measured by enzyme-linked immunosorbent assay in 45 patients with diabetic nephropathy. The presence of MCP-1 in diseased kidneys was determined by immunohistochemical and in situ hybridization analyses. RESULTS: Urinary MCP-1 levels were significantly elevated in patients with diabetic nephrotic syndrome and advanced tubulointerstitial lesions. Moreover, urinary levels of MCP-1 were well correlated with the number of CD68-positive infiltrating cells in the interstitium. In contrast, serum MCP-1 levels remained similar to those of healthy volunteers. Furthermore, we detected the MCP-1-positive cells in the interstitium of diabetic nephropathy via both immunohistochemical and in situ hybridization analyses. CONCLUSION: These observations suggest that locally produced MCP-1 may be involved in the development of advanced diabetic nephropathy, especially in the formation of tubulointerstitial lesions possibly through Mphi recruitment and activation. Moreover, up-regulation of MCP-1 may be a common pathway involved in the progressive tubulointerstitial damage in diabetic nephropathy as well as inflammatory renal diseases.     

Urinary excretion of monocyte chemoattractant protein-1 in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) progresses to renal insufficiency in >50% of patients and is characterized by interstitial inflammation and fibrosis in the end stage. In a rat model of ADPKD, monocytes accumulate within the renal interstitium in association with increased levels of monocyte chemoattractant protein-1 (MCP-1) in cyst mural cells and increased excretion of this chemokine into the urine. For determining the extent to which this chemokine is abnormally expressed in patients with ADPKD, a cross-section study was performed of MCP-1 in urine, serum, and cyst fluid and MCP-1 production by mural epithelial cells cultured from the cysts of human patients with ADPKD. Upper boundaries for urinary MCP-1 excretion (>263 pg/mg creatinine) and serum creatinine concentration (>1.5 mg/dl) determined in 19 normal individuals were used to sort 55 ADPKD patients into three groups. In group 1 (n = 13), urine MCP-1 excretion (136 +/- 14 pg/mg creatinine) was not different from normal volunteers (152 +/- 16 pg/mg); serum creatinine levels and urine total protein excretion were normal as well. In group 2 (n = 27), urine MCP-1 excretion was increased (525 +/- 39 pg/mg creatinine), but serum creatinine levels and urine protein excretion were not different from normal. In group 3 (n = 15), urine MCP-1 excretion increased further (1221 +/- 171 pg/mg), serum creatinine levels increased to 4.3 +/- 0.8 mg/dl, and urine protein excretion rose to 0.64 +/- 0.28 mg/mg creatinine. Serum MCP-1 levels of ADPKD patients (84 +/- 9.9 pg/ml; n = 15) did not differ from normal. Levels of MCP-1 much higher than in serum or urine were found in cyst fluids obtained from nephrectomy specimens (range, 767 to 40,860 pg/ml; mean, 6434 +/- 841 pg/ml; n = 73). Polarized, confluent cultures of ADPKD cyst epithelial cells secreted MCP-1 into the apical fluid to levels eightfold greater than in the basolateral medium. Similar results were obtained with tubule epithelial cells cultured from normal human renal cortex. On the basis of these results, it is concluded that urinary excretion of MCP-1 is increased in the majority of adult patients with ADPKD and that the source of some of this chemokine may be the mural epithelium of cysts. Furthermore, it seemed that urinary MCP-1 excretion may have increased in these ADPKD patients before appreciable increases in serum creatinine concentration or urine protein excretion were detected. It is reasonable to include urine MCP-1 excretion among candidate surrogate markers in controlled, longitudinal studies of ADPKD.     

肾脏病患者尿液中三种分子的检测及其与肾小球新月体病变的关系

目的 探讨检测肾脏病患者尿液中单核细胞趋化蛋白1（MCP-1）、壁层上皮细胞标志物β-catenin和角蛋白（CK）19分子的方法，并分析这些分子水平与肾小球新月体病变的关系。方法 应用酶联免疫吸附试验(ELISA)方法，对正常人和肾脏病患者肾活检当日和部分患者肾活检后1个月晨尿中的MCP-1、β-catenin和CK19分子水平进行检测。将其结果与患者尿蛋白定量、肾功能、肾组织中细胞性新月体指数和纤维性新月体指数进行相关分析。比较甲基泼尼松龙冲击治疗前后上述指标的变化。结果 肾脏病患者尿MCP-1、β-catenin和CK19水平均较正常对照组显著升高（P < 0.01）。细胞新月体组患者尿MCP-1、 β-catenin水平较无新月体组显著升高[(MCP-1水平M(范围）247.54(22.17～2335.18) ng/mmol Cr 比 113.55(1.75～1057.77) ng/mmol Cr；尿β-catenin 水平M（范围)219.40 (0.93～3827.50) ng/mmol Cr 比82.30(4.03～1632.58) ng/mmol Cr P均< 0.01]。上述3种分子水平和细胞新月体指数呈正相关（r = 0.75、0.21、0.63，P 均< 0.01）。甲基泼尼松龙冲击治疗后，尿MCP-1、CK19水平较治疗前显著降低（M分别减少45%、57%，P< 0.01）。 结论 应用ELISA方法可以检测肾脏病患者尿MCP-1、β-catenin和CK19的水平，且尿液中上述分子水平与肾组织细胞性新月体程度呈正相关。     

Urinary monocyte chemoattractant protein-1 (MCP-1) is a marker of active renal vasculitis.

BACKGROUND: Macrophage infiltration and cytokine production are important in the pathogenesis of crescentic glomerulonephritis in anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis. The aim of this study was to investigate whether urinary levels of chemokines, monocyte chemoattractant protein-1 (MCP-1) and fractalkine, were useful tools for non-invasive assessment of renal vasculitis. METHODS: In a prospective study, concentrations of chemokines were measured in urine and serum samples using specific enzyme-linked immunosorbent assays, and related to the patients' clinical status. Renal expression of MCP-1 was studied by immunohistochemical staining of renal biopsies. RESULTS: Urinary levels of MCP-1 were significantly higher in patients with active (P<0.01) or persistent (P<0.05) renal vasculitis, in comparison with healthy volunteers, control patients, patients with inactive vasculitis and patients with extra-renal disease only. There were no differences in serum concentrations of MCP-1 between these groups. Reduction in urinary MCP-1 levels following treatment preceded the improvement of renal function by a median of 2 weeks. In one patient, rising urinary levels of MCP-1, despite immunosuppressive therapy, was associated with progression to severe renal failure. There were no differences in urinary fractalkine levels between the different groups of patients and controls. Immunohistology of renal biopsies from patients with crescentic glomerulonephritis showed increased staining for MCP-1 in glomerular and interstitial cells. Urinary MCP-1 levels correlated with glomerular, but not tubulointerstitial, macrophage infiltration (P<0.05). CONCLUSIONS: This study shows that measurement of urinary MCP-1, but not fractalkine, is a useful non-invasive technique for the assessment of renal involvement and monitoring the response to therapy in ANCA-associated vasculitis.     

Activated cells in urine and monocyte chemotactic peptide-1 (MCP-1)--sensitive rejection markers in renal graft recipients

Chemokines induced during an acute immune alloresponse cause cellular infiltration of the allograft. These chemokines and cells are excreted with urine. The aim of the study was to assess the diagnostic utility of urinary excretion of monocyte chemotactic peptide-1 and certain cells involved in infiltration i.e. CD3+, CD64+ and HLA-DR+ cells. The study entailed 35 patients with acute renal rejection and 65 with a stable graft function. Urinary sediments were prepared by means of cytospin and stained with anti-CD3, anti-CD64, anti-HLA-DR labeled monoclonal antibodies. Urinary expression of MCP-1 was assayed by ELISA. In the patients with acute rejection MCP-1 level was ten-fold higher than in the patients with a stable graft function (6.1+/-3.4 vs 0.6+/-0.4 ng/mg creatinine). The number of CD3+ cells was over 5 times higher than in the non-rejection patients (13.4+/-4.6 vs 2.5+/-2.2). The number of HLA-DR+ cells was 6 times higher in the acute rejection patients (15.7+/-5.9 vs 2.5+/-2.7). The number of CD64+ cells was significantly increased in the patients during an acute rejection episode (p<0.0001). CD3+, HLA-DR+ and CD64+ cell counts strongly correlated with urine excretion of MCP-1. The counts of CD3+ and HLA-DR+ cells correlated with Banff score. The assessment of MCP-1 as well as CD3+, CD64+ and HLA-DR+ cells can provide a useful non-invasive device for the diagnosis of acute rejection. A sole assay of HLA-DR+ cell excretion provides enough specificity and sensitivity for the routine monitoring of patients after kidney transplantation, saving costs and time.     

Increased urinary excretion of monocyte chemoattractant protein-1 during acute renal allograft rejection

BACKGROUND.: Acute rejection is characterized histologically by infiltrationof the interstitium by mononuclear cells. Monocyte chemoattractantprotein 1 (MCP-1) has recently been identified as a monocytechemotactic factor. This study examined the possible role ofMCP-1 in renal transplantation. METHODS.: The concentration of MCP-1 in urine and serum of 19 renal transplantpatients was investigated using an inhibition radioimmunoassay.The patients were divided into a non-rejection (NRj) and a rejection(Rj) group. Normal healthy volunteers were included as controls.Immunoperoxidase staining for MCP-1 and CD14, as a marker formacrophages, was performed in renal biopsies of transplant patientswith rejection and six biopsies from histologically normal kidneys,as controls. The size of urinary MCP-1 was determined by gelfiltration chromatography and in a number of fractions assessedfor monocyte chemotactic activity using a modified, Boyden chamberassay. RESULTS.: Urinary excretion of MCP-1 in the Rj group ranged between 250ng/mmol Cr and 3148 ng/mmol Cr with a median of 612 ng/mmolCr. This is significantly higher than the results in the NRjgroup, ranging between 47 ng/mmol Cr and 388 ng/mmol Cr witha median of 229 ng/mmol Cr. In the normal control group, urinaryMCP-1 levels ranged between 38 ng/mmol Cr and 74 ng/mmol Crwith a median of 50 ng/mmol Cr. The fractional excretion ofMCP-1, calculated on the basis of MCP-1 and creatinine clearances,was found also to be significantly higher in the Rj group ascompared to the NRj group. However, there was no significantdifference in the serum levels of MCP-1 between the Rj, NRj,and normal control group. The intensity of MCP-1 staining intubular epithelial cells and the degree of CD14⁺ cells in theinterstitium was significantly higher in renal allograft biopsiesthan in the normal kidneys. In addition, MCP-1 isolated fromurine of renal transplant patients with rejection was filteredwith apparent molecular weight of 13 kDa and 11 kDa. Both sizesare chemotactically active for monocytes. CONCLUSIONS.: These data suggest that urinary excretion of MCP-1 can be usedas a marker for the episodes of acute rejection. The increaseof urinary excretion of MCP-1 most likely is the result of localproduction by tubular epithelial cells. MCP-1 produced locallymay, at least in part, be responsible for the influx of macrophagesinto the interstitium during rejection.     

肾移植患者尿液中单核细胞趋化性肽-1浓度变化的意义

目的　探讨肾移植受者尿液中单核细胞趋化性肽 1(MCP 1)浓度变化的意义。方法　用生物素 抗生物素蛋白复合物酶联免疫吸附试验 (ABC ELISA法 )检测 5 0例肾移植受者术后不同时间尿液中MCP 1的含量。结果　移植术后肾功能稳定者尿液中的MCP 1水平为 (416± 2 1) μg/L ,正常对照组为 (40 8± 11) μg/L ,二者间的差异无显著性 (P >0 .0 5 ) ;术后发生急性排斥反应者的MCP 1水平为 (1195± 5 8) μg/L ,明显高于正常对照组和肾功能稳定者 (P <0 .0 1) ;抗排斥治疗有效者的MCP 1水平在冲击治疗 1周后即明显下降 (P <0 .0 1) ,而无效者的MCP 1水平无变化。结论　检测尿液中的MCP 1水平有助于急性排斥反应的诊断及预后判断。     

Increased urinary excretion of monocyte chemoattractant protein-1 in proteinuric renal diseases

Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that is produced mainly by tubular epithelial cells in kidney and contributes to renal interstitial inflammation and fibrosis. More recently, we have demonstrated that urinary MCP-1 excretion is increased in proportion to the degree of albuminuria (proteinuria) and positively correlated with urinary N-acetylglucosaminidase (NAG) levels in type 2 diabetic patients. Based on these findings, we have suggested that heavy proteinuria, itself, probably aggravates renal tubular damage and accelerates the disease progression in diabetic nephropathy by increasing the MCP-1 expression in renal tubuli. In the present study, to evaluate whether urinary MCP-1 excretion is increased in the proteinuric states not only in diabetic nephropathy but also in other renal diseases, we examined urinary MCP-1 levels in IgA nephropathy patients with macroalbuminuria (IgAN group; n = 6), and compared the results with the data obtained from type 2 diabetic patients with overt diabetic nephropathy (DN group; n = 23) and those without diabetic nephropathy (non-DN group; n = 27). Urinary MCP-1 excretion levels in non-DN, DN, IgAN groups were 157.2 (52.8-378.5), 346.1 (147.0-1276.7), and 274.4 (162.2-994.5) ng/g creatinine, median (range), respectively. Expectedly, urinary MCP-1 and NAG excretion levels in DN and IgAN groups were significantly elevated as compared with non-DN group. Therefore, we suggest that MCP-1 expression in renal tubuli is enhanced in proteinuric states,irrespective of the types of renal disease, and that increased MCP-1 expression probably contributes to renal tubular damage in proteinuric states.     

Urinary transforming growth factor-beta-induced gene-h3 (betaig-h3) as a sensitive predictor in chronic cyclosporine nephrotoxicity

Transforming growth factor (TGF)-beta is involved in the pathogenesis of chronic cyclosporine nephrotoxicity (CyAN). Since the expression of TGF-beta induced gene h3 (betaig-h3) is up-regulated by TGF-beta, we evaluated the potential role of betaig-h3 as a sensitive urinary marker to monitor the progression/regression of chronic CyAN. Urinary betaig-h3 levels were determined using an enzyme-linked immunosorbent assay in nine patients with chronic CyAN and 13 patients with stable graft function. We scored the extent of tubulointerstitial fibrosis (TIF) and using immunoperoxidase labeling, determined betaig-h3 expression in renal tissues of patients with chronic CyAN. Urinary betaig-h3 excretion was higher in chronic CyAN compared to control subjects (173.4+/-26.0 vs 62.6+/-5.0 ng/mg creatinine, P<.01). In chronic CyAN, the degree of TIF correlated with increased urinary betaig-h3 levels (r=.785, P<.05). In kidneys with chronic CyAN, betaig-h3 labeling was more prominent at the basement membranes (BM) of the tubules where inflammatory cells had infiltrated the surrounding interstitium. Moreover, the BM of the atrophied tubules and their surrounding interstitium were strongly labeled. Urinary betaig-h3 levels decreased from 173.4+/-26.0 to 64.9+/-14.4 ng/mg creatinine at 1 month after discontinuation of CyA or reduction in CyA dosage (P<.01) despite unchanged serum creatinine levels. Urinary betaig-h3 levels increased in patients with chronic CyAN and decreased after discontinuation or reduction of CyA dosage. Our results suggested that urinary betaig-h3 levels could be used as a sensitive urinary marker to monitor the progression or regression of chronic CyAN.     

Urinary levels of epidermal growth factor, interleukin-6 and monocyte chemoattractant protein-1 may act as predictor markers of renal function outcome in immunoglobulin A nephropathy

Aim:   Urinary cytokine excretion may reflect histological changes in immunoglobulin A nephropathy (IgAN), and their measurement can give information about disease outcome.
Methods:   Thirty-three IgAN patients were prospectively followed for 5.6 ± 3.1 years. Urinary levels of monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-6 and epidermal growth factor (EGF) were measured at diagnosis and repeated 1 year later for IL-6 and EGF.
Results:   Urinary MCP-1 and IL-6 levels were increased significantly, while EGF excretion reduced in IgAN patients, compared to controls. IL-6 urinary levels showed significant positive correlation with chronic histological lesions. Patients were classified into five groups, according to the Haas classification system. MCP-1 and IL-6 urinary levels were increased, whereas EGF levels were reduced in the progression of staging. EGF urinary excretion was a strong predictor factor of disease outcome, significantly correlated with creatinine clearance at time of diagnosis ( r  = 0.5, P  = 0.005), and at the end of follow up ( r  = 0.6, P  = 0.001). Urinary EGF levels measured a year later could predict long-term outcome better, and a cut of 0.05 pg/mg urine creatinine levels could distinguish between progressors and non-progressors.
Conclusion:   Urinary MCP-1, IL-6 and EGF levels may represent histology in IgAN. EGF excretion can be a predictive marker and its serial measurements may give information about disease outcome and the effect of treatment.     

Pentoxifylline ameliorates proteinuria through suppression of renal monocyte chemoattractant protein-1 in patients with proteinuric primary glomerular diseases

Proteinuria (albuminuria) reflects dysfunction of the glomerular permeability barrier in which inflammatory cytokines play a key role. Pentoxifylline (PTX) is a phosphodiesterase inhibitor that possesses potent anti-inflammatory and immunomudulatory effects. This study evaluated the effectiveness of PTX to reduce proteinuria and inflammatory mediators in patients with proteinuric primary glomerular diseases. Seventeen patients with primary glomerular diseases, a persistent spot proteinuria exceeding 1.5 g/g creatinine (Cr) and a glomerular filtration rate between 24 and 115 ml/min/1.73 m(2) were treated with PTX 400 mg twice daily for 6 months. Before and after the treatment, serum Cr, plasma renin activity and aldosterone concentrations, plasma and urinary tumor necrosis factor (TNF)-alpha, interleukin-1beta and monocyte chemoattractant protein (MCP)-1, as well as urinary protein and Cr were measured. PTX significantly reduced urinary protein excretion, along with an increase of serum albumin. A significant correlation existed between the basal urinary protein/Cr and the basal urinary MCP-1/Cr ratios. PTX lowered the urinary MCP-1/Cr ratio, and the percent reduction of urinary protein/Cr ratio correlated directly with the precent decrease of urinary MCP-1/Cr ratio after PTX treatment. There was no significant change in blood pressure, renal function, biochemical parameters, plasma renin activity and aldosterone concentrations, or plasma TNF-alpha and MCP-1 levels during the study. In conclusion, administration of PTX 800 mg per day is safe and effective for reducing proteinuria in patients with proteinuric primary glomerular diseases. This beneficial effect occurs in close association with a reduction of urinary MCP-1 excretion.     

Mast cells in rapidly progressive glomerulonephritis.

The role of mast cells (MC) in tubulointerstitial damage in glomerulonephritis (GN) is not fully understood. The distribution of MC was compared in renal biopsies from 50 patients with different stages of rapidly progressive GN (RPGN) and in 20 control samples. The immunoreactivity of renal MC with anti-tryptase and anti-chymase antibodies was studied. Interstitial myofibroblasts were stained with anti-alpha-smooth muscle actin (alpha-SMA) antibody, and inflammatory cells were identified by anti-CD3, -CD20, and -CD68 monoclonal antibodies. Positively stained cells were counted, and the relative interstitial and fractional areas of anti-alpha-SMA-stained cells were measured. MC were rarely found in control samples. In contrast, samples showing crescentic GN contained numerous tryptase-positive MC (MC(T)) (43.7+/-4.65 versus 7.14+/-1.3/mm2) and fewer tryptase- and chymase-positive MC (MC(TC)) (13.8+/-1.86 versus 1.89+/-0.86/mm2) in the renal interstitium but never in the glomerulus. Double immunostaining demonstrated the presence of both phenotypes of MC. Accumulation of MC was significantly correlated with the numbers of T lymphocytes (MC(T), r = 0.67) and interstitial macrophages (MC(T), r = 0.455). There was also a significant correlation between the number of MC(T) and the relative interstitial area. The number of MC(TC) was well correlated with the fractional area of alpha-SMA-positive interstitium (r = 0.749) and the percentage of the interstitial fibrotic area (r = 0.598). There was also a significant negative correlation between interstitial MC(TC) accumulation and creatinine clearance (r = 0.661). The density of MC(TC) was higher (1.4-fold) in advanced forms of GN associated with fibrocellular crescents and interstitial fibrosis. These results show the potential involvement of MC in the fibroproliferative process in the renal interstitium of patients with RPGN. The results indicate that these cells constitute part of the overall inflammatory cell accumulation in RPGN.     

Proinflammatory effects of iron sucrose in chronic kidney disease

Inflammation is a central component of progressive chronic kidney disease (CKD). Iron promotes oxidative stress and inflammatory response in animals and promotes progressive CKD. Parenteral iron provokes oxidative stress in patients with CKD; however, its potential to provoke an inflammatory response is unknown. In 20 veterans with CKD, 100 mg iron sucrose was administered intravenously over 5 min and urinary excretion rate and plasma concentration of monocyte chemoattractant protein-1 (MCP-1) were measured at timed intervals over 24 h. Patients were then randomized to placebo or N-acetyl cysteine (NAC) 600 mg b.i.d. and the experiment was repeated at 1 week. Iron sucrose markedly increased plasma concentration and urinary excretion rate of MCP-1 at baseline and at 1 week visits (P < 0.0001 for time effect). Urinary excretion peaked at 30 min and plasma concentration at 15 min. Plasma MCP-1 concentration fell from 164 +/- 17.7 to 135 +/- 17.7 pg/ml with NAC, whereas it remained unchanged from 133 +/- 12.5 to 132 +/- 17.7 pg/ml with placebo (P=0.001 for visit x antioxidant drug interaction). There was a reduction in MCP-1 urinary excretion rate from visit 1 to 2. At the baseline visit, the urinary excretion rate averaged 305 +/- 66 pg/min and at the second visit 245 +/- 67 pg/min (mean difference 60 +/- 28 pg/min, P = 0.030). There was no improvement in urinary MCP-1 excretion with NAC. In conclusion, iron sucrose causes rapid and transient generation and/or release of MCP-1 plasma concentration and increases urinary excretion rate, and systemic MCP-1 level but the urinary excretion rate is not abrogated with the antioxidant NAC. These results may have implications for the progression of CKD with parenteral iron.     

Renal, major histocompatibility complex antigens and cellular components in rapidly progressive glomerulonephritis identified by monoclonal antibodies

Identification of crescent-forming cells in rapidly progressive glomerulonephritis (RPGN) is very difficult, and controversial results on the participation of different epithelia as well as of monocytes have been reported. In the present study different monoclonal antibodies were used to analyze cellular infiltrates of crescents and the interstitium as well as the distribution of well-defined renal antigens and major histocompatibility complex (MHC) encoded antigens along the human nephron in cryostat sections of renal biopsies from patients with RPGN. The results demonstrate that monocytes/macrophages infiltrate Bowman's space and that cellular components of crescents present with phenotypes of parietal glomerular and proximal tubular cells. T lymphocytes are significantly found in glomeruli and also in interstitium with predominance for CD4+ lymphocytes. Reduction of MHC class-II antigens within diseased glomeruli correlates with changes in renal antigen expression. Tubular cells, however, often presented an abnormal expression of MHC class-II antigens. Differences of renal and MHC-encoded antigen expression may be due to rapid regeneration episodes of renal parenchymal cells in RPGN.     

Monocyte chemoattractant protein-1 expression correlates with monocyte infiltration in the post-ischemic kidney

Chemokines play a prominent role in the acute inflammatory response in several models of kidney disease. We reported that monocyte chemotactic peptide-1 (MCP-1) mRNA is increased by ischemia-reperfusion injury. In this report, we examined the effects of ischemia-reperfusion injury on the kinetics and location of MCP-1 protein expression, the excretion of MCP- 1 protein in the urine and on the infiltration of mononuclear cells in the kidney. Pair-fed Sprague-Dawley rats underwent bilateral renal ischemia (50 min) or sham ischemia and placed in metabolic cages for daily urine collections. Kidneys were harvested at d. 1, 3, 7, and 10 after ischemia-reperfusion (I-R) or sham-ischemia (S-I). Kidney MCP-1 mRNA levels were increased on d. I and 3 post-ischemia. Kidney MCP-1 protein levels were increased in the I-R group on d. 1 and 3. MCP-1 expression occurred predominantly in the distal tubule segments by immunohistology. There was an increase in monocytes/macrophages infiltration in the I-R group, compared to the S-I or controls by d. 1. Urinary MCP-1 excretion increased 3-fold in the I-R group, and remained elevated above the S-I group and baseline levels, on d. 3 through d. 8. Kidney MCP-1 mRNA levels, protein levels and urinary MCP-1 excretion rates are increased by ischemia-reperfusion injury. The areas of increase in MCP-1 chemoattractant expression correlates with an increase in monocyte infiltration in the kidney. Although its pathophysiologic role remains to be determined, MCP-1 may participate in, and be a biomarker for, the mononuclear inflammatory processes that occur after ischemia-induced acute renal failure.     

Expression of the chemokine monocyte chemoattractant protein-1 and its receptor chemokine receptor 2 in human crescentic glomerulonephritis

Crescents are morphologic manifestations of severe glomerular injury. Several chemokines and their receptors have been demonstrated to be involved in animal models of crescentic glomerulonephritis (cGN) and are potential targets for therapeutic interventions. Therefore, the expression of monocyte chemoattractant protein-1 (MCP-1), its receptor chemokine receptor 2B (CCR2B), and CCR5 in human cGN was studied. MCP-1 and CCR2B mRNA expression was evaluated, by in situ hybridization, in serial sections of 23 renal biopsies from patients with cGN. T cells, macrophages, and CCR5-expressing cells were examined by immunohistochemical analysis. MCP-1 mRNA was expressed by cells in crescents, parietal epithelium, and tubular epithelium, as well as by infiltrating leukocytes in the tubulointerstitium. The expression of CCR2B mRNA was observed in cells in glomeruli and crescents and in infiltrating leukocytes in the tubulointerstitium. CCR2B mRNA expression could not be clearly localized to intrinsic renal cells; evidence that most of the CCR2B-expressing cells were leukocytes is provided. CD3-positive T cells formed the major part of the interstitial cell infiltrates but were rare within the glomerular tufts. CD68-positive macrophages constituted a major population of infiltrating cells in crescents and contributed significantly to the interstitial infiltrates. The number of glomerular macrophages was associated with the number of MCP-1- and CCR2B-positive glomerular cells. Expression of CCR2B was significantly correlated with interstitial CD3-positive T cells. CCR5 expression was restricted to infiltrating leukocytes and was correlated quantitatively and by localization with interstitial CD3-positive T cells and CD68-positive macrophages. These first morphologic data on the distribution of CCR2-positive cells in human cGN suggest differential effects of chemokines and their receptors on the distribution of infiltrating leukocytes in different compartments of the kidney.     

Enhanced expression of C chemokine lymphotactin in IgA nephropathy

Leukocyte accumulation in the kidney is observed in patients with IgA nephropathy. Chemokines are a large family of cytokines chemotactic for leukocytes and have been shown to be upregulated in renal diseases. We previously reported that the gene expression of lymphotactin, a sole member of C chemokine subfamily, is enhanced in an animal model of crescentic glomerulonephritis, but its expression in human renal diseases is totally unknown. In the present study, we investigated the expression of mRNAs of lymphotactin and some other chemokines in IgA nephropathy. The expression of mRNAs for three chemokines, lymphotactin, MCP-1, and MIP-1beta, in renal cortex was increased and the levels of lymphotactin and MCP-1 mRNAs were statistically higher in patients with glomerular crescents than in those without crescents. These levels also correlated with tubulointerstitial changes and urinary protein excretion. Glomerular levels of mRNAs for lymphotactin and MCP-1, but not MIP-1beta, were higher in IgA nephropathy than controls. By immunohistochemical analysis, lymphotactin was detected in tryptase-positive cells (putative mast cells) in the interstitial space. These results suggest that lymphotactin, as well as MCP-1, may contribute to leukocyte infiltration and disease progression in IgA nephropathy.     

单核细胞趋化因子-1在间质性膀胱炎中表达的研究

目的 探讨单核细胞趋化因子-1(MCP-1)在间质性膀胱炎(IC)患者膀胱组织和尿液中的表达水平及其意义. 方法根据美国国立糖尿病、消化、肾病协会IC诊断标准确诊女性IC患者35例,感染性膀胱炎(UI)患者20例,肾囊肿患者25例作为正常对照组.IC患者平均年龄47(31～65)岁.主诉下腹酸胀/疼痛和夜尿次数多,伴有尿频尿急;已生育30例.均行24 h排尿卡记录、IC症状及问题评分表(O'Leary-Sant评分表)、钾离子敏感试验(PST)和麻醉状态下水扩张后膀胱镜检查.膀胱镜检查获取3组患者膀胱组织和尿液样本,免疫组化染色方法观察MCP-1在IC组织中的表达分布.RT-PCR技术测定3组膀胱组织中MCP-1 mRNA表达水平,酶联免疫吸附试验测定3组尿液标本中MCP-1水平. 结果 IC、UI、对照组尿液标本中MCP-1浓度分别为(74.1±36.9)、(280.6±68.9)、(10.8±6.9)pg/ml;膀胱组织中MCP-1相对定量值分别为76.2±24.0、99.5±30.1、36.1±14.1.lC组和UI组中组织/尿液中MCP-1表达水平均高于正常对照组,差异有统计学意义(P＜0.01).IC组临床症状评分为(14.9±1.8)分,与MCP-1升高水平呈正相关(r=0.686). 结论 IC患者膀胱组织和尿液中MCP-1表达升高,可能成为IC诊断的非特异性免疫指标之一.     

Oxalate ions and calcium oxalate crystal-induced up-regulation of osteopontin and monocyte chemoattractant protein-1 in renal fibroblasts

OBJECTIVE: To examine the responses of renal fibroblasts to high oxalate (Ox) and calcium Ox (CaOx) crystals, as the latter are found in the renal interstitium of patients with primary or enteric hyperoxaluria, and in animals with experimental CaOx nephrolithiasis, and are associated with tubulointerstitial inflammation (TI). TI might begin with the production of chemoattractants by the renal epithelial cells exposed to high Ox and/or CaOx crystals; as Ox levels are also high in the renal interstitium and crystal deposition in nephrolithiasis might start in the interstitium, we hypothesized that renal fibroblasts might also be involved in the development of TI. MATERIALS AND METHODS: We exposed renal fibroblast cells of line NRK 49F in vitro to Ox ions (500 micromol/L) or CaOx monohydrate crystals (67 microg/cm(2)). We assessed the production of osteopontin and monocyte chemoattractant protein-1 (MCP-1), and expression of their mRNA, in the cells. We also determined the cellular malondialdehyde content as a marker of reactive oxygen species (ROS)-induced lipid peroxidation, and Trypan blue staining and the release of lactate dehydrogenase as markers of injury. RESULTS: Similar to renal epithelial cells, renal fibroblasts were stimulated by exposure to Ox and CaOx crystals. They showed signs of injury and ROS-induced lipid peroxidation. The mRNA expression and production of osteopontin and MCP-1 increased significantly. CONCLUSIONS: These results indicate that fibroblasts respond to high Ox and CaOx crystals by up-regulating specific pathways producing pro-inflammatory conditions. Migration of monocytes/macrophages to sites of interstitial crystal deposits can lead to localized interstitial inflammation and fibrosis.     

Messenger RNA expression of target genes in the urinary sediment of patients with chronic kidney diseases.

BACKGROUND: The degree of renal scarring in kidney biopsy is an important prognostic factor in patients with chronic kidney diseases. We hypothesize that gene expression in the urinary sediment reflects the degree of renal damage. METHODS: We studied 29 patients with chronic kidney disease who underwent kidney biopsy (12 immunoglobulin-A nephropathy and 17 glomerulosclerosis) and 10 healthy controls. The mRNA expressions of a panel of target genes in urinary sediment were measured by real-time quantitative polymerase chain reaction. The results were compared with the degree of histological damage and renal function decline. RESULTS: There were significant differences in the urinary expression of transforming growth factor-beta (TGF-beta), monocyte chemotactic protein-1 (MCP-1) and collagen IV between disease groups and controls. Urinary TGF-beta mRNA expression correlated significantly with estimated glomerular filtration rate (r = -0.412, P = 0.029) and the degree of tubulointerstitial scarring (r = 0.418, P = 0.024). Urinary MCP-1 expression correlated with the degree of glomerulosclerosis (r = 0.450, P = 0.014), but not tubulointerstitial scarring. Urinary MCP-1 expression correlated with its corresponding level by enzyme-linked immunosorbent assay (ELISA) (r = 0.650, P<0.001), but TGF-beta expression did not correlate with its ELISA level. Urinary TGF-beta gene expression correlated with its intra-renal expression in glomeruli (r = 0.701, P<0.001) and tubulointerstitium (r = 0.573, P = 0.001) by immunohistochemistry, while urinary MCP-1 gene expression correlated with its staining in glomeruli (r = 0.576, P = 0.001) but not tubulointerstitium. After 12 months, there was a significant inverse correlation between the rate of renal function decline and urinary expression of connective tissue growth factor (r = -0.471, P = 0.010) and collagen I (r = -0.399, P = 0.032), but not TGF-beta or MCP-1. CONCLUSIONS: Amongst the target genes examined, the mRNA expression of TGF-beta in urinary sediment correlated with renal function, the degree of histological damage and intra-renal level in patients with chronic kidney diseases. Measurement of TGF-beta mRNA expression in urine may be a useful non-invasive tool for assessing the severity of renal damage in patients with chronic kidney diseases.