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IgA nephropathy (IgAN) is one of the most common primary glomerulonephritis worldwide and one of the leading causes of end staged renal disease (ESRD) in young patient. But treatment options are limited. And with the available treatment option, about 20-40% progresses to ESRD over 20 years. Interstitial fibrosis (IF) is an important prognostic marker that determine course of disease and progression to ESRD in which transforming growth factor-β (TGF-β) plays a central role. It has been reported that Phosphodiesterase V inhibitor (PDE5i) inhibit reduces the fibrosis by inhibiting TGF-β. But its role in IgA nephropathy including pathophysiology is yet to define. Hence, in the current in-vitro study we have studied the role of PDE5i as an inhibitor of renal fibrosis in IgAN.
Material and Methods:
This is a pilot study to evaluate the efficacy of ‘Phosphodiesterase V inhibitor’ on TGFβ1 induced fibrosis on fibroblasts derived from biopsy specimen of IgA nephropathy patients. Renal fibroblasts were cultured from 6 IgA patients. The fibroblasts cells were treated with PDE5i inhibitor (tadalafil) (at different doses of 1µm, 5µm, 10µm and 15µm), both before and after stimulation with transforming growth factor beta-1 (TGF-b1) (at doses of 5ng/ml, 10ng/ml, 15ng/ml and 20ng/ml). Gene expression was studied by real-time polymerase chain reaction (RT-PCR) for messenger ribonucleic acid (mRNA) of pro-fibrotic genes Col1a1, Col1a2, FN1, CTGF, ASMA, TIMP1, and anti-fibrotic MMP2.
Objectives:
1. To evaluate the effect of PDE5 inhibitors on TGFβ1 induced profibrotic genes (Col1a1, Col1a2, ASMA1, FN1, CTGF, and TIMP1) expression at mRNA level.
2. To Evaluate the Effect of PDE5 inhibitors on TGFβ1 induced expression of anti-fibrotic gene (MMP2) at mRNA level.
Our results shows that TGFβ significantly increased the expression of profibrotic gene (Col1a1, Col1a2, ASMA, CTGF, FN and TIMP1) at concentration of 10 ng/ml in the fibroblast cells derived from IgAN patients. Treatment of fibroblast cells with Tadalafil (PDE5 inhibitor) significantly decreased the pro-fibrotic gene mRNA expression (Col1a1, Col1a2, ASMA, CTGF, FN and TIMP1) with increased anti-fibrotic gene expression (MMP2) at the dose of 5µm and 10 µm concentration in the fibroblast cells (Figure 1).
This study may provide potential therapeutic target for prevention of renal fibrosis in IgAN patients. Till date PDE5 inhibitors were not used for IgAN. We found that, PDE5 inhibitor reduces the fibrosis in this in vitro study, this drug may be proposed as a potential therapy for IgAN.