Uric acid correlates with the severity of histopathological parameters in IgA nephropathy.

BACKGROUND: Immunoglobulin-A nephropathy (IgAN) is the most common chronic glomerulonephritis worldwide. Many clinical and histopathological risk factors for progression have been found previously. Recently, metabolic risk factors, such as hyperuricaemia and hypertriglyceridaemia, also have been associated with the progression of IgAN. METHODS: In the present study we correlated clinical and metabolic risk factors with histopathological parameters in 202 patients with IgAN. Morphological changes in glomerular, tubulointerstitial and vascular tissue were semiquantitatively graded into three classes. Mesangial proliferation activity and the amount of inflammatory cells were also evaluated by immunohistochemical staining of Ki-67 (MIB-1), CD45 (LCA) and CD68 stainings. Serum uric acid, triglycerides and cholesterol, urine protein excretion (UPE), blood pressure and body mass index (BMI) were measured. Smoking habits and occurrence of diabetes mellitus also were evaluated. The independent role of serum uric acid in the development of renal morphological changes was evaluated in multivariate analysis. RESULTS: Serum uric acid and UPE level correlated with several histological parameters. Uric acid level showed the strongest correlation with tubulointerstitial changes and UPE with glomerulosclerosis. The level of serum triglycerides correlated with interstitial fibrosis and hyaline arteriolosclerosis. Blood pressure correlated with hyaline arteriolosclerosis, glomerulosclerosis and tubulointerstitial changes. BMI and diabetes mellitus correlated with both tubulointerstitial and vascular changes. We found no significant correlations between histopathological parameters and smoking habits or serum cholesterol level. Serum uric acid had independent associations with the presence of tubular atrophy and interstitial fibrosis and inflammation. CONCLUSIONS: We conclude that many metabolic factors are univariately associated with renal morphological findings in IgAN. These same factors are central in the metabolic or insulin resistance syndrome and may have a pathogenetic role in the progression of IgAN. Serum uric acid may have an independent role in development of tubulointerstitial lesions as well as being associated with inflammation in renal tissue of patients with IgAN.     

Tubular and interstitial expression of ICAM-1 as a marker of renal injury in IgA nephropathy

BACKGROUND: The upregulated renal expression of intercellular adhesion molecule 1 (ICAM-1) is associated with glomerular and interstitial infiltration of leukocytes. AIM: To test the hypothesis that renal expression of ICAM-1 may be predictive in the highly variable IgA nephropathy (IgAN). METHODS: ICAM-1 (CD54) in tubular epithelium and interstitial leukocytes, macrophages (CD14), and T cells (CD3) were assessed using avidin-biotin-peroxidase in renal biopsy specimens from 45 patients with IgAN and from 29 patients with no glomerulonephritis. RESULTS: In IgAN, tubular ICAM-1+ was seen in 25 of 45 (55%) biopsy specimens, associated with glomerular hypercellularity, glomerulosclerosis involving less than 50% of the glomerular area, interstitial cellular infiltration, tubular atrophy, and proteinuria (U = 44, p = 0.005). Interstitial ICAM-1+ leukocytes were correlated with glomerulosclerosis involving less and more than 50% of the glomerular area, tubular atrophy, interstitial fibrosis, and serum creatinine concentration (r = 0.6343, p < 0.001). In patients with an increase of 50% in the serum creatinine concentration, interstitial ICAM-1+ leukocytes and CD14+ and CD3+ cells were significantly more numerous than in patients with a stable creatinine concentration. In patients with no glomerulonephritis, tubular ICAM-1+ was seen in 7 of 29 (24%) biopsy specimens, inversely correlated with the number of normal glomeruli and associated with glomerulosclerosis covering more than 50% of the glomerular area, tubular atrophy, and creatinine. CONCLUSIONS: Tubular and interstitial expression of ICAM-1 can be a marker of tubulointerstitial disturbance in IgAN. Interstitial ICAM-1 may be an adverse predictor of disease progression.     

Dendritic cell and M2 macrophages are associated with the severity of disease in IgA nephropathy patients

Objective To investigate the number and distribution of dendritic cells (DCs), macrophages and M2 macrophages in renal tissues of patients with IgA nephropathy (IgAN) and their correlation with clinicopathological parameters, and explore its role in the progression of IgAN. Methods Renal tissue samples from 42 patients aged ≥18 years with IgAN were collected by kidney biopsy in Guangdong Provincial People's Hospital from January 2018 to June 2018. The patients were divided into different groups according to Oxford classification and Lee grade classification criteria. The distribution and number of DCs (CD209), macrophages (CD68) and M2 macrophages (CD68 and CD206) were detected by immunohistochemistry. Spearman correlation test was used to analyze the correlation between the number of DCs and macrophages in renal tissues and clinical pathological parameters. Results The number of DCs in the glomeruli of the M1, T0 and C1 groups increased significantly compared with the M0, T1 and C0 groups, and the number of DCs in the renal interstitium of the T1 group increased significantly compared with the T0 group (all P＜0.05). The number of glomerular macrophages in group C1 was significantly higher than that in group C0. The number of macrophages in S1, T1 and Lee IV-V tubulointerstitial groups was significantly higher than that in S0, T0 and Lee II-III groups (P＜0.05). The number of M2 macrophages in the S1, T1 and Lee IV-V groups was significantly higher in the tubulointerstitial group than in the S0, T0 and Lee II-III groups (all P＜0.05). The blood urea nitrogen, serum creatinine and 24 h urine protein levels in the T1 and Lee IV-V groups were significantly higher than those in the T0 and Lee II-III groups, and the serum albumin levels in the Lee IV-V group were significantly lower (all P＜0.05). Spearman correlation analysis showed that the number of DCs in renal interstitium was positively correlated with the proportion of tubulointerstitial fibrosis. There were a positive correlation between the proportion of glomerular segmental sclerosis and tubulointerstitial fibrosis and renal interstitial macrophages and M2 macrophages. The number of M2 macrophages was positively correlated with serum creatinine and 24 h urine protein (both P＜0.05). Conclusions The number of DCs and M2 macrophages in kidneys are positively correlated with the clinicopathological features of IgAN patients, which indicates that they may be associated with disease progression.     

Compartment specific expression of dendritic cell markers in human glomerulonephritis

Macrophages and dendritic cells are heterogenous and highly plastic bone marrow-derived cells that play major roles in renal diseases. We characterized these cells using immunohistochemistry in 55 renal biopsies from control patients or patients with glomerulonephritis as an initial step towards postulating specific roles for these cells in kidney disease. In proliferative glomerulonephritis numerous CD68 positive (pan monocyte, macrophage and dendritic marker) cells were found in both glomeruli and the tubulointerstitial space, however, a myeloid dendritic cell marker (DC-SIGN) was identified only in the tubulointerstitium. A significant number of plasmacytoid dendritic cells (identified as BDCA-2 positive cells) were seen at sites of interstitial inflammation, including follicular aggregates of inflammatory cells. Langerin positive cells (a marker of Langerhans' cells) were detectable but rare. The area of either CD68 or DC-SIGN positive interstitial cells correlated with serum creatinine. Low levels of DC-SIGN, DC-LAMP and MHC class II mRNA were present in the tubulointerstitial space in controls and increased only in that region in proliferative glomerulonephritis. We demonstrate that the CD68 positive cells infiltrating the glomerulus lack dendritic cell markers (reflecting macrophages), whereas in the tubulointerstitial space the majority of CD68 positive cells are also DC-SIGN positive (reflecting myeloid dendritic cells). Their number correlated with serum creatinine, which further emphasizes the significance of interstitial DCs in progressive glomerular diseases.     

正常血压IgA肾病患者动脉病变的意义

目的:传统观点认为动脉硬化与高血压有关。然而,部分IgA肾病患者,尽管血压正常,但仍有动脉硬化的改变。本研究的目的就是比较血压正常、伴有和不伴有动脉病变的IgA肾病患者的临床病理特点,探讨正常血压IgA肾病患者肾内动脉病变的影响因素及意义。方法:所有患者均经肾活检诊断为原发性IgA肾病,无高血压病史,肾活检前血压<140/90mmHg。动脉病变的定义为活检肾组织光镜下见动脉壁增厚和(或)动脉玻璃样变。符合标准的105例患者,根据动脉病变的有无分为两组,有动脉病变组52例、无动脉病变组53例,分别比较两组的临床病理特点。肾脏动脉病变的半定量分级标准:0:无损害;1:<25%;2:≥25%,<50%;3:≥50%。统计学方法:分别比较两组的临床病理特点,将差异有统计学意义的单因素指标作为多因素分析的入选指标,采用逐步回归方法分析动脉病变的影响因素,以P<0.05作为差异有统计学意义。结果:与无动脉病变组比较,动脉病变组肾活检时的年龄、血肌酐、血尿酸、尿蛋白定量、尿NAG酶、肾小球硬化、肾小管萎缩以及肾间质纤维化的程度显著增高,尿渗透压显著下降。多因素分析的结果表明,肾活检时的血肌酐、尿渗透压、肾小管萎缩及肾间质纤维化是正常血压IgA肾病动脉病变的独立影响因素。动脉病变的程度与血肌酐、肾小管萎缩及肾间质纤维化呈正相关;与尿渗透压呈负相关。结论:血压正常IgA肾病患者的肾内动脉病变,主要与年龄、血肌酐、血尿酸增高等因素有关,常伴有肾小管间质损害。     

Renal interstitial tenascin immunostaining and immune cell infiltration in IgA nephropathy

SUMMARY: Interstitial expression of tenascin and interstitial leucocyte infiltration were examined by an indirect immunoperoxidase method using monoclonal antibodies against tenascin, CD45 (all leucocytes), CD45RO (T cells) and CD68 (monocytes/macrophages) on renal biopsy specimens from 25 patients with mesangial proliferative IgA-positive glomerulonephritis (IgAN). Ten biopsy kidney specimens, which were removed because of renal trauma, were used as the control group. In patients with IgAN, the mean interstitial expression of tenascin was significantly higher than in the control group. Strong tenascin staining was detected in areas with interstitial damage. In patients with IgAN there were positive correlations between the interstitial expression of tenascin and the relative interstitial cortical volume, as well as serum creatinine. In the IgAN patents, a significant increase in the total number of interstitial CD45-immunopositive cells, CD45RO-positive and CD68-positive cells was seen compared with the control group. In patients with IgAN, immunostaining of tenascin did not correlate with the number of T-cells, monocytes/macrophages or all leucocytes in the renal interstitium. These results suggest that in patients with IgAN the interstitial accumulation of tenascin did not depend on the type or the density of interstitial inflammatory infiltrates.     

Factors associated with progression of IgA nephropathy are related to renal function--a model for estimating risk of progression in mild disease

BACKGROUND: A number of factors are linked to the outcome of IgA nephropathy (IgAN). However, it has been difficult to compare results of studies since patient populations have varied greatly. There were 3 aims in the study reported here, namely to compare factors associated with renal outcome in IgAN patients with different levels of renal function on diagnosis; to determine factors which were independently associated with progression of renal disease in initially mild IgAN; and to create a model for the estimation of the risk of progression in individual IgAN patients with normal renal function on diagnosis. METHODS: Two hundred and fifty-nine IgAN patients who had been followed on average for 9.1 (SD 4.5) after diagnosis were divided into 2 groups on the basis of renal function on diagnosis. In group 1 (98 patients), Ccr (creatinine clearance, estimated by the Cockcroft-Gault formula) was < 85 ml/min, in group 2 (161 patients) > or = 85 ml/min. Univariate analyses were used to find significant differences between progressors and non-progressors in both groups. Logistic regression analysis was used to determine factors independently associated with progression in group 2. RESULTS: Several factors were found to be associated with outcome in both groups, such as hypertension, level of Ccr, serum cholesterol, proteinuria, and also histopathological changes. Factors associated with progression in patients with initially decreased renal function (group 1), were predictable, such as male sex, absence of episodes of macroscopic hematuria, serum urate level and degree of tubular atrophy. Surprisingly, in patients with initially normal renal function (group 2), numbers of urinary erythrocytes were associated with outcome. The factors independently associated with progression in this group were number of urinary erythrocytes, existence of hypertension and in histopathology arteriolosclerosis and the level of glomerular score. A model for estimating risk of progression on the basis of various combinations of factors found to be independently associated with outcome is presented. CONCLUSIONS: We concluded that association between variable and outcome in IgAN depends partly on renal function at the time of assessment of the factor. Since there are factors which are independently associated with the outcome of early and apparently mild disease, early diagnosis of IgAN is desirable: outcome in mild IgAN can be predicted reliably on the basis of factors found to be independently associated with outcome.     

The product of duration and amount of proteinuria (proteinuria index) is a possible marker for glomerular and tubulointerstitial damage in IgA nephropathy

BACKGROUND/AIMS: IgA nephropathy (IgAN) is one of the major causes for chronic renal failure (CRF). Presence of massive proteinuria, hypertension, increased serum creatinine level and sclerotic histopathological changes of the glomerulus are known to be determinants for the progression of CRF. However, the relationships between duration of proteinuria/hematuria and histopathological changes, which may be correlated with the renal prognosis, have not been clarified. METHODS: A cross-sectional, univariate analysis of clinical parameters on the four glomerular and three tubulointerstitial histopathological grades in 57 untreated biopsy-proven IgAN patients (M/F = 32/25) was performed. RESULTS: The age at the time of renal biopsy (35.2 +/- 13.0 years; mean +/- SD), average duration of proteinuria (5.3 +/- 5.8 years), mean urinary protein excretion (0.99 +/- 1.22 g/day), serum creatinine (Cr 0.97 +/- 0.28 mg/dl), Cr clearance (Ccr 75.5 +/- 29.4 ml/min), and blood urea nitrogen (BUN 15.4 +/- 3.9 mg/dl) were well correlated with both histopathological grades. The product of duration (years) and urinary protein excretion (g/day) at the time of renal biopsy was more significantly correlated with glomerular and tubulointerstitial histopathological grades and serum Cr. CONCLUSION: The natural course of IgAN is steadily progressive depending on the duration and amount of proteinuria. The product of these two factors (proteinuria index) may be a useful predictor for glomerular and interstitial histopathological changes and the fate of renal function in IgAN.     

GMP-17-positive T-lymphocytes in renal tubules predict progression in early stages of IgA nephropathy

Treatment of patients with IgA nephropathy (IgAN) depends on a reliable assessment of disease progression based on measurements of glomerular filtration rate (GFR), proteinuria, hypertension, and tubulointerstitial changes. We sought to determine whether progression could be predicted from analysis of glomerular and tubulointerstitial inflammation in biopsies taken at an early stage of IgAN. We retrospectively analyzed biopsies from 50 patients, relating the subsequent clinical course to infiltration with B- and T-lymphocytes, granule membrane protein of 17 kDa (GMP-17) positive cytotoxic T cells, macrophages, fibroblasts, and tubulointerstitial expression of human leukocyte antigen-D related (HLA-DR). At biopsy, 19 patients had decreased GFR while 13 of 31 patients with normal GFR and progressive IgAN differed significantly from 18 non-progressors in the level of proteinuria and in the severity of scores for mesangial proliferation, tubular atrophy, interstitial fibrosis, and interstitial infiltrates. On multivariate regression analysis these differences disappeared; however, associations with GMP-17-positive cytotoxic T-lymphocytes in intact renal tubules and of B-lymphocytes in the interstitium remained significant. Our study may have identified a marker of disease progression in early stages of IgAN.     

骨形成蛋白7和转化生长因子β1在不同病理类型IgA肾病的变化

目的 观察转化生长因子β1（TGF-β1）和骨形成蛋白7（BMP-7）在不同病理类型IgA肾病的变化,并探讨其意义。方法 89例IgA肾病患者分成3组：A组为47例轻度系膜增生性IgA肾病;B组为29例中重度系膜增生性IgA肾病;C组为13例增生硬化或硬化性IgA肾病。检测患者的血压、尿蛋白量（24 h）、Scr和Ccr。免疫组化和ELISA方法测定患者肾组织冰冻切片及其血、尿中TGF-β1和BMP-7水平。计算患者病理切片硬化肾小球数、新月体数和间质纤维化面积百分比。结果 随着IgA肾病患者肾小球病变的加重,肾小管萎缩和肾间质纤维化增多,其血压、尿蛋白量（24 h）、Scr逐渐增加,除B、C两组间尿蛋白量（24 h）无显著差异外,其余各组间差异均有统计学意义（P＜0．05）。与A组比较,B组肾组织及血、尿TGF-β1明显增多,C组显著降低（P＜0．01）。肾组织冰冻切片及血、尿BMP-7随着肾脏病变的加重,水平逐渐下降（P＜0．01）;而且与Ccr呈正相关;与血压、Scr、尿蛋白量（24 h）、硬化肾小球数、新月体数、肾间质纤维化面积呈负相关。结论 TGF-β1在IgA肾病系膜增生严重时明显增加,肾脏广泛纤维化时明显降低,可能参与了IgA肾病肾间质纤维化的发生。BMP-7随肾脏病变的加重而明显降低,可能导致其抗肾纤维化作用减弱。     

Altered P-selectin and CD44 expression in the renal tissues and peripheral blood of children with IgA nephropathy

Objective  To understand the role of P-selectin (CD62P) and CD44 in mediating immune inflammation in the nephrotic process of children with IgA nephropathy (IgAN), cooperative expression of CD62P and CD44 in peripheral blood and renal tissues of IgAN children was investigated and its association with changes of histopathologic, serologic, and urinary properties was tested. Material and methods  Forty-six IgAN children were divided into three groups according to pathologic grades and clinical features. Fifteen blood samples from normal children and four normal renal biopsy specimens were used as controls. Plasma level of CD62P was detected by double antibody sandwich immunoradiometric assay; ELISA was used to determine serum level of CD44. Expression of CD62P and CD44 in renal tissues was determined by immunohistochemistry. Results  Cooperative expression of CD62P and CD44 was detected in renal tissues and peripheral blood of IgAN children. Altered expression of CD62P and CD44 in peripheral blood significantly correlated not only with hematuria, proteinuria, serum cholesterol, and albumin, and with urine NAG and β₂-MG, but also with degree of tubulointerstitial injury in IgAN children. Conclusion  The evidence supported CD62P and CD44 as initial and promoting factors mediating immune inflammation in the nephrotic process in IgAN children. The cooperative expression profiles of CD62P and CD44 in renal tissues and peripheral blood combined with serologic and urinary predictors may be important in diagnosis of progression in children with IgAN.     

Clinical significance of costimulatory molecules CD80/CD86 expression in IgA nephropathy

BACKGROUND: IgA nephropathy (IgAN) is the most common form of human glomerulonephritis. Tubulointerstitial inflammation with infiltration of mononuclear cells plays an important role in the progression of IgAN. Activation of T cells requires costimulatory signals through binding of CD28 receptor with cognate ligands (CD80/CD86) located on antigen-presenting cells (APC). To assess the clinical significance of this regulatory pathway participation in the pathogenesis of IgAN, a comprehensive immunohistologic evaluation was conducted on renal tissue of IgAN in different phases of progressive injury. METHODS: Thirty-three cases of IgAN and ten cases of non-IgA mesangial proliferative glomerulonephritis (PGN) with minor tissue damage as controls were investigated. Monoclonal antibodies were used to assess the expression of CD80, CD86, CD68, CD14, CD45RO, human leukocyte antigen-DR (HLA-DR), and intercellular adhesion molecule-1 (ICAM-1) in renal tissues. Clinical and expression data were compared at the time of renal biopsy. RESULTS: CD80+ and CD86+ cells were observed more in IgAN patients with progressive renal injury than in mild cases and controls. CD80 was limited to tubular epithelial cells and was complemented by HLA-DR expression. CD86 was expressed in the glomerulus, periglomerular area, and peritubular interstitium. Activated T cells (CD45RO+), monocytes (CD14+), macrophages (CD68+), and CD86 showed similar distributions. Positive correlations were found between CD86+ cells and CD45RO, CD14, and CD68 positive cells and between CD80+ tubuli and peritubular interstitial CD45RO+ cells. The number of interstitial CD86 positive cells and the percentage of CD80+ tubuli were correlated with renal function. Most CD86+ cells were monocyte/macrophages. CONCLUSION: This study suggested that CD80 and CD86 activate T cells in IgAN, CD80/CD86 expressions correlated with renal function at the time of renal biopsy, and monocyte/macrophages and tubular epithelial cells act as APC.     

Does circulating erythropoietin reflect progression of IgA nephropathy? Comparison with urinary N-acetyl-beta-D-glucosaminidase.

BACKGROUND: Recent reports describe that erythropoietin (Epo) is produced by peritubular interstitial fibroblast-like cells in response to a hypoxic stimulus. We studied serum Epo levels as a possible marker of tubulointerstitial damage in the progression of IgA nephropathy (IgAN), in comparison with urinary (u-) levels of N-acetyl-beta-D-glucosaminidase (NAG), which is mainly derived from proximal tubular cells and is used as a marker of tubular damage. METHODS: Thirty-eight patients with IgA nephropathy (IgAN) with relatively preserved renal function (serum creatinine: sCr, 0.5-2.2 mg/dl) were examined. The severity of glomerulosclerosis and interstitial fibrosis of the renal biopsy tissue was expressed by semiquantitative grading scores. Clinical parameters including serum creatinine (sCr), blood pressures, and 24-h proteinuria levels were obtained at the renal biopsy. Epo was measured by a radioimmunoassay (RIA) of sera obtained in the morning and u-NAG was measured by colorimetric method of 24-h urine samples. RESULTS: The mean Epo level of the patients (17.7+/-6.3 mU/ml) was not different from the control level (19.3+/-3.7 mU/ml). There were no significant correlations between Epo levels and red blood cell (RBC) counts, haematocrit (Hct), or haemoglobin (Hb) levels. The mean u-NAG level of the patients (6.7+/-6.2 U/gCr) was significantly higher than the control level (1.9+/-0.5 U/gCr). There was an inverse quantitative correlation between Epo and u-NAG levels in the patients (P<0.02). The u-NAG levels showed quantitative positive correlations with sCr (P<0.001), u-proteins (P<0.001), systolic (SBP) (P<0.001), and diastolic blood pressures (DBP) (P<0.05). Conversely, Epo levels were inversely correlated with sCr, SBP and DBP (each P<0.05). The patients with higher u-proteins (>2.0 g/day) showed significantly decreased Epo levels (P<0.05) than those with lower u-proteins (<2.0 g/day). The both scores of glomerulosclerosis and interstitial fibrosis were positively correlated with the u-NAG levels (each P<0.001), but were not correlated with the Epo levels. CONCLUSIONS: The significant correlation between u-NAG and serum Epo levels suggests that tubular damage and interstitial cell dysfunction are associated each other in the progression of IgAN. Serum Epo levels bearing inverse correlations with sCr, blood pressure levels and heavy proteinuria seem to reflect clinical severity of IgAN, whereas u-NAG can be more useful progression marker of IgAN bearing correlations with both clinical and histological findings.     

Related factors of hyperuricemia in IgA nephropathy patients

Objective To investigate the influencing factors of hyperuricemia in patients with IgA nephropathy (IgAN). Methods A retrospective study was performed in patients with renal biopsy diagnosed as IgAN in the Department of Nephrology, Provincial Hospital of Anhui Medical University from January 2016 to October 2018. According to the blood uric acid level, they were divided into two groups: patients with hyperuricemia and patients without hyperuricemia. The general clinical indicators and renal pathological data were compared between the two groups. Logistic regression model was used to analyze the influencing factors of hyperuricemia in IgAN patients. Results A total of 125 IgAN patients with age of (35.70±11.16) years old were enrolled, including 63 males and 62 females. The morbidity of hyperuricemia was 44.0%(55/125). Compared with the normal blood uric acid group, the blood urea nitrogen, serum creatinine and the proportion of chronic kidney disease (CKD) stage 3-5, small arterial wall thickening, fibrous crescents/globules, renal interstitial fibrosis, renal tubular atrophy, glomerular sclerosis and inflammatory cell infiltration in the hyperuric acid group were higher, while the level of estimated glomerular filtration rate (eGFR) was lower. And the differences were statistically significant (all P＜0.05). Multivariate logistic regression analysis showed that the level of serum creatinine was an independent related factor of hyperuricemia in IgAN patients (OR=1.034, 95%CI 1.005-1.064, P=0.021). Conclusions IgAN patients with hyperuricemia presented more severe glomerular, tubular and interstitial lesions, and the level of serum creatinine is an independent related factor of hyperuricemia in IgAN patients. High uric acid level may have an important influence on the progression of IgAN, so good control of serum uric acid may improve the prognosis of patients with IgAN.     

存在肾小动脉微血管病变且非高血压IgA肾病患者的临床病理特点和预后分析

目的总结和分析非高血压的IgA肾病(IgA nephropathy,IgAN)合并肾小动脉微血管病变(microangiopathy,MA)患者的临床病理特点和预后。方法抽取北京大学第一医院IgAN前瞻性队列人群中非高血压成人患者,重新进行病理阅片,根据肾小动脉病变,分为MA组、动脉硬化病变(AS)组和无血管病变组,分析其临床病理及预后特点。复合肾脏终点事件包括终末期肾病或估算肾小球滤过率(eGFR)下降≥30%。采用Cox回归模型分析预后的危险因素。结果共420例IgAN患者被纳入本研究,其中37(8.8%)例患者合并MA,134(31.9%)例合并AS,其余249例无血管病变。相对于AS组或无血管病变组,合并MA的患者尿蛋白量更严重[1.47(1.08,2.84)g/d比1.31(0.68,2.56)g/d、1.04(0.55,2.00)g/d,P=0.002],肾功能更差[eGFR:(75.3±26.5)ml·min-1·(1.73 m2)-1比(85.7±27.0)ml·min-1·(1.73 m2)-1、(98.6±24.8)ml·min-1·(1.73 m2)-1,P<0.001],并有更高的节段性肾小球硬化和(或)球囊粘连(S1)、肾小管萎缩/间质纤维化(T1/2)、细胞/细胞纤维新月体病变(C1/2)比例(均P<0.05)。随访期间,合并MA的患者发生终点事件比例更高[54.1%比33.6%、32.9%,χ2=6.491,P=0.039]。Cox多因素分析模型显示,MA是IgAN发生进展的独立危险因素(HR=1.872,95%CI 1.044~3.357,P=0.035),而其他类型血管病变不影响预后。结论非高血压IgAN患者合并MA不少见,这提示高血压并非导致IgAN血管病变的唯一危险因素。     

人类IgA肾病间质小管中炎性细胞的研究

目的探讨人类IgA肾病(IgAN)间质小管中炎性细胞(CD4+、CD8+、CD25+、MAC387+、27E10+)与临床肾功能以及病理的关系。方法对36例IgAN患者肾组织石蜡切片行PAS染色及免疫组化染色(CD4、CD8、CD25、MAC387、27E10),利用电子图像分析系统测量间质小管面积(mm2),计算单位面积间质小管中炎性细胞数目。结合病理指数(肾小球硬化,肾小管萎缩,间质纤维化程度)及肾活检前后肾功能,用SPSS软件包进行统计学分析。结果在肾间质小管中,CD4+、CD8+细胞均与间质纤维化呈正相关(r=0.38、0.37,P均<0.05):CD8+细胞与肾小球硬化相关(r=0.40,P<0.05)。间质CD4+、CD8+以及MAC387+细胞数均与肾活检前Scr呈正相关(r=0.37、0.39、0.36,P均<0.05)。多元逐步回归分析显示,CD8+以及MAC387+细胞数是预测肾功能的主要相关因素。4例ESRD患者27E10+细胞数明显多于非ESRD患者组。结论浸润于间质小管中的CD4+、CD8+、MAC387+在IgAN的肾功能和肾组织损伤中可能发挥重要作用。CD8+、MAC387+细胞数是影响IgAN预后的独立因素。间质27E10+细胞可能是预测IgAN进展的有效因子。     

Association of interleukin-10 gene G-1082A polymorphism with the progression of primary glomerulonephritis

BACKGROUND: Interleukin-10 (IL-10) is a cytokine with immunosuppressive properties. We evaluated the influence of G-1082A polymorphism in the IL-10 gene promoter, which has been associated with modified IL-10 production, on the two most common forms of primary glomerulonephritis: IgA nephropathy (IgAN) and focal segmental glomerulosclerosis (FSGS). METHODS: We studied Caucasian patients (N= 191) with biopsy-proven glomerulonephritis (IgAN: N= 123, FSGS: N= 68) followed-up for 6.5 +/- 5.5 years. Patients were classified according to the slope of reciprocal serum creatinine (>/= or <-0.1 dL(*)mg(-1) (*)year(-1)) into group A (slow progressors, IgAN: N= 75, FSGS: N= 47) and group B (fast progressors, IgAN: N= 48, FSGS: N= 21). One hundred healthy volunteers were analyzed as control patients. G-1082A polymorphism was determined by polymerase chain reaction (PCR) amplification. RESULTS: The allele frequencies were similar in patients and control group (NS). Initial renal function, proteinuria, and blood pressure did not differ significantly between patients with different genotypes. G-1082A polymorphism was associated with the progression of both IgAN and FSGS: GA/AA genotypes were more frequent in group B (fast progressors) than in group A (slow progressors; P= 0.012 for IgAN, P < 0.05 for FSGS). Patients with the GA/AA genotypes showed a worse outcome in the Kaplan-Meier analysis of renal survival (P < 0.05 for both IgAN and FSGS). The IL-10 polymorphism remained an independent risk factor for progression in multivariate analysis (Cox regression model, P < 0.05 for IgAN and FSGS). CONCLUSION: Our results suggest that IL-10 gene G-1082A polymorphism is an important marker of progression in patients with IgAN and FSGS.     

Macrophage accumulation in human progressive diabetic nephropathy

BACKGROUND: Diabetic nephropathy is a major global health problem. Progression to renal failure is common; however, the mechanisms are unknown. Experimental models suggest a role for macrophages. Therefore, macrophage accumulation and its relationship to the subsequent clinical course were studied. METHODS: A retrospective study of baseline histology and the subsequent clinical course over at least 5 years involving 20 consecutive patients with a histological and clinical diagnosis of diabetic nephropathy was performed. The relationship between macrophage accumulation in renal biopsy tissue (KP-1/anti-CD68+ cells), baseline measures of known predictors of progression (proteinuria, tubulointerstitial damage, myofibroblast accumulation) and progression over 5 years (plot of reciprocal of serum creatinine) was quantified. RESULTS: Accumulation of macrophages was apparent in the glomeruli (2.8 + 0.7/gcs vs 1.0 + 0.2 for normals, P = not significant) and interstitium (296.9 + 63.3/mm(2) vs 19.0 + 1.3/mm(2) for normals, P = 0.002) of patients with diabetic nephropathy. Glomerular macrophage number correlated with baseline serum creatinine (r = 0.548, P = 0.012) but not with progression of renal failure as glomerular macrophages were prevalent in early, but not advanced diabetic nephropathy. Interstitial macrophage accumulation correlated strongly with serum creatinine (r = 0.649, P = 0.002), proteinuria (r = 0.779, P < 0.0001), interstitial fibrosis (r = 0.774, P < 0.0001) and inversely with the slope of 1/serum creatinine (r = -0.531, P = 0.023). CONCLUSION: Macrophages accumulate within glomeruli and the interstitium in diabetic nephropathy and the intensity of the interstitial infiltrate is proportional to the rate of subsequent decline in renal function. These human data support animal studies that suggest a pathogenic role for the macrophage in diabetic nephropathy.     

The correlation between serum levels of oxidative stress indicators and renal interstitial fibrosis in patients with IgA nephropathy

Objective To investigate the relationship between serum levels of oxidative stress indicators and the degree of renal interstitial fibrosis in patients with IgA nephropathy (IgAN). Methods Seventy eight patients with confirmed primary IgAN in General Hospital of Ningxia Medical University from January 2013 to December 2014 were enrolled. The patients were divided into T0 group (n=30), T1 group (n=26) and T2 group (n=22) according to the grade of tubular atrophy/interstitial fibrosis of Oxford pathological classification criteria for IgAN in 2009. Meanwhile, thirty cases of health examiner were enrolled as control subjects. The levels of serum malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were detected by xanthine oxidase method, thiobarbituric acid spectrophotometry method, ultraviolet spectrophotometry method, chemical colorimetric method, respectively. The levels of serum advanced oxidation protein products (AOPPs), transforming growth factor beta 1 (TGF-β1), monocyte chemotactic protein 1 (MCP-1), transforming growth factor alpha (TGF-α), interleukin 6 (IL-6) and hypoxia inducible factor 1 alpha (HIF-1α) were detected by enzyme linked immunosorbent assay (ELISA) in all groups. Spearman correlation analysis was used to analyze the correlation between serum oxidative stress indicators and traditional risk factors of tubular atrophy/renal interstitial fibrosis. Multivariable linear regression analysis was used to analyze the correlation between oxidative stress indicators and degree of renal tubular atrophy/renal interstitial fibrosis. Results There were differences in serum levels of AOPPs, MDA, SOD, CAT and GSH-Px in IgAN patients with different degrees of renal interstitial fibrosis (all P﹤0.05). With the increase of renal interstitial fibrosis, the levels of AOPPs and MDA increased gradually, while the levels of SOD, CAT and GSH-Px decreased gradually. Serum AOPPs, MDA, SOD, CAT, GSH-Px concentration in IgAN patients were correlated with the mean arterial pressure (MAP), total blood protein (TP), albumin (Alb), Scr, uric acid (UA), 24-hour urinary protein volume and estimated glomerular filtration rate (eGFR). Multivariate regression analysis showed that the AOPPs levels of blood were positively correlated with MAP, Scr, UA and 24-hour urinary protein (all P﹤0.01), and negatively correlated with TP, Alb, eGFR (all P﹤0.05). The serum levels of AOPPs and MDA in IgAN patients were positively correlated with the levels of TGF-β1, MCP-1, TGF-α, IL-6 and HIF-1α. The levels of SOD, CAT and GSH-Px were negatively correlated with the levels of TGF-β1, MCP-1, TGF-α, IL-6 and HIF-1α. Multivariate stepwise regression analysis showed that the degree of renal interstitial fibrosis in IgAN patients was positively correlated with serum AOPPs level (β=0.285, P=0.001), negatively correlated with CAT (β=-0.346, P﹤0.001), GSH-Px (β=-0.303, P﹤0.001). Conclusions The level of serum oxidative stress in IgAN patients is elevated and positively correlated with the degree of renal interstitial fibrosis, suggesting that oxidative stress may be involved in the occurrence and development of renal interstitial fibrosis.     

Fibroblast-specific protein 1 is a specific prognostic marker for renal survival in patients with IgAN

BACKGROUND: There is little direct evidence that fibroblasts are involved in the progression of the renal interstitial fibrosis in human glomerulonephritis. With the availability of a new specific marker for fibroblasts, we determined the presence of fibroblasts in kidneys with IgA nephropathy (IgAN) and correlated their numbers with various clinical parameters. In particular, we also prospectively asked if the number of fibroblasts in the renal interstitium correlates with prognosis. METHODS: Cells positive for fibroblast-specific protein 1 (FSP1) were localized in renal biopsy specimens using immunohistochemistry with anti-FSP1 antibody. Clinical features were analyzed by one-way analysis of variance (ANOVA) with the Bonferroni correction. To assess the prognostic impact of the number of FSP1+ fibroblasts on renal survival in 142 patients with normal serum creatinine, the relationship between covariates to renal survival were evaluated univariately using the log-rank test and multivariately using Cox proportional hazards. RESULTS: Fibroblasts identified by their expression of FSP1 accumulate in areas showing severe interstitial fibrosis. Some tubular epithelial cells undergoing epithelial-mesenchymal transition (EMT) in fibrotic areas also express FSP1. Numbers of FSP1+ fibroblasts directly correlate with serum creatinine (r = 0.74, P < 0.0001) and inversely correlate with estimated creatinine clearance (r = -0.54, P < 0.0001), and by multivariate analysis, the clinical factors influencing renal survival are urinary protein excretion [> or = 1.0 g/day, relative risk (RR) = 4.20, P= 0.032], hypertension (RR 5.85, P = 0.0027), and > or = 20 FSP1+ fibroblasts per high power field (HPF) (RR 7.39, P = 0.0015). Staining for FSP1+ fibroblasts is largely nonoverlapping with alpha-smooth muscle actin+ (alpha-SMA) cells in the interstitium. CONCLUSION: The target protein FSP1 identifies human fibroblasts and tubular epithelium undergoing EMT, and distinguishes them from the diaspora of alpha-SMA+ vascular smooth muscle cells. FSP1+ fibroblasts are critically related to the progression of IgAN; consequently, staining FSP1 in renal biopsy specimens provides a valuable histologic index of progression.