ABSTRACT
Objective To investigate the injury of podocyte and its association with proteinuria in IgA nephropathy (IgAN). Method Thirty-five patients of IgA nephropathy with proteinuria more than 1.0 g/24 h were enrolled in the study, and eight cases of renal harmatomaeetomy or renal cancinomaectomy were as controls. Cell cycle regulatory proteins (p21, p27), podocyte-associated molecules (integrin-β1, nephrin, α-actinin 4, nestin), foot process width (FPW) and the amount of podocyte were examined by immunohistochemistry and real-time PCR, respectively. Patients were divided into two groups according to podocyte number per volume (Nv): podocytopenia group (n=15, Nv<52.49×106/μm3) and normal number group (n=20, Nv≥52.49× 106/μm3). Proteinuria was followed up for eighteen months. Results Compared with the controls, podocyte p21 was re-expressed, while the expression of p27 was decreased (0.71±0.12 vs 0.91±0.07, P<0.05) in IgAN. The nestin protein level was markedly decreased in IgAN (13.4%± 0.04% vs 17.6%±0.04%, P<0.05). The mRNA expression of integrin-β1 was significantly increased (12.54±5.20 vs 1.02±0.30, P<0.05), while the amount of nephrin, α-actinin4 remained unchanged. Effacement of foot processes and podocyte detachment from the glomerulax basement membrane were observed in some cases. Nv was significantly less than that of controls (161.27± 225.92 vs 323.22±138.12, P<0.05), which was associated with the Lee's grade of IgA nephropathy. The integrin-β1 mRNA expression and Nv were negatively correlated with baseline proteinuria by univariate analysis (r=-0.840, P=0.034; r =-0.4483, P=0.014, respectively). Proteinuria in podocytopenia group was decreased more slowly than that in normal number group. Conclusions Podocyte injury exsists in IgAN with proteinuria, which manifests alterations in cell cycle regulatory protein and some podocyte-associated molecules, as well as foot process effacement and loss of pedocyte. Podocyte injury may be involved in proteinuria by affecting the progression of proteinuria in IgAN.
ABSTRACT
Objective To clarify whether the Cosmc gene down-regnhtion in lgA nephropathy (IgAN) patients is resulted from genetic disorders or external suppressions. Methods Forty IgAN patients, 16 non-IgAN glomerulonephritis patients and 21 healthy controls were enrolled in the study. Genomie DNA was extracted and then Cosmc gene was amplified and sequenced. Peripheral B lymphoeytes were isolated and cultured with RPMI-1640 alone or plus lipopolysaecharide (LPS). The Cosmc mRNA expression levels at baseline, after RPMI-1640 culture or RPMI-1640+LPS treatment were measured respectively by real-time RT-PCR. Results (1) Only 2 missense mutations and 2 silent mutations were detected in coding frame region of Cosine gene in 2 IgAN patients. (2) The baseline Cosmc gene expression level was significantly lower in IgAN patients (31% of that in healthy controls) than that in healthy controls. (3) Relative quantification PCR indicated that Cosmc mRNA expression level was significantly increased (219% of baseline) after RPMI-1640 culture, and treatment of LPS could strongly inhibit this effect. (4) The Cosmc gene expression of healthy control was not affected by RPMI-1640 or LPS. Conclusion It is not genetic disorders but external suppression to cause the down-regulation of Cosmc gene mRNA expression in IgAN.
ABSTRACT
Objective To investigate the effects of CD4+CD25high regulatory T cells(Treg)and the imbalance of helper T lymphocyte subsets(Th1/Th2)on the immunological mechanism of IgA nephropathy(IgAN)patients. Methods The percentage of Treg and helper T cells subpopulation (Th1/Th2)in the peripheral blood of IgAN patients and healthy controls was examined by flow cytometry.The FOXP3 expression was detected through intracellular staining.The correlation of Treg or Th1/Th2 with clinical parameters of IgAN was analyzed by Spearman or Pearson rank correlation test. Results The percentages of Treg and Th2 cells were significantly higher in peripheral blood of IgAN patients compared to that of healthy controls[Treg (2.14±0.82)%vs[1.59±0.53)%,Th2(2.57±0.72)%vs(1.81±1.10)%,all P＜0.05].Th1/Th2 ratio was significantly reduced in IgAN patients(5.75±1.89 vs 12.73±9.79,P＜0.05).The percentage of circulating Treg cells was positively correlated with serunl IgA concentration(r=0.397,P＜0.05),and was negatively correlated with eGFR(r=-0.376,P＜0.05).The percentage of circulating Th2 cells was positively correlated with serum IgA(r=0.468,P＜0.05). Conclusions There is a disorder of T lymphocyte population in the peripheral blood of IgAN patients.The increased Treg and Th2 cells may play an important role in the pathogenesis of IgAN.