X. Wang1, P. Duann1, C. Lu1, C. Moles1, M. Fahrenholtz1, M. Rae1, H. Li1, J. Cheng2, S. Balaji1, S. Keswani1 1Baylor College Of Medicine,Surgery,Houston, TX, USA 2Baylor College Of Medicine,Medicine,Houston, TX, USA
Introduction:
Tubulointerstitial fibrosis, compounded with peritubular capillary loss, is a common finding in progressive renal disorders. Treating progressive renal disorders patients’ costs over $40 billion annually in the US alone. Beyond dialysis and transplantation, novel therapies are needed. Previous reports suggest that there is a role for the anti-inflammatory cytokine, interleukin-10 (IL-10), in attenuating renal fibrosis in a disease murine model. We and others also showed that IL-10 can regulate angiogenesis and endothelial progenitor recruitment during dermal and ischemic cardiac tissue repair. We hypothesize that IL-10 can promote angiogenesis and regulate TGFβ isoforms in unilateral urethral obstruction (UUO) murine model.
Methods:
Primary fibroblasts (FB) were isolated from 8-10 week-old male C57BL/6J (WT) mice. IL-10 (50 ng/ml or 200 ng/ml) was added to cultures. VEGF and TGFβ-1 gene expressions were assessed by qPCR at 1, 2, 3 and 6h. Levels of TGFβ-1 and TGFβ-3 were determined at 48h by ELISA. Eight week-old WT and IL-10 null male mice were injected with lenti-IL-10/lenti-GFP (1×1010 IU) under kidney capsule. Three days after the injection, unilateral ureteral obstruction (UUO) was performed. UUO/sham kidneys and serum were collected at 14 days after UUO for RNA, ELISA and immunohistochemical analysis. Data presented as mean ± SD, n=3/treatment group. P value by ANOVA.
Results:
In primary FB culture, IL-10 treatment increased VEGF expression and altered the differential expression of TGFβ isoforms, with three-fold increment of ratio between TGFβ-3 to TGFβ-1. The role of IL-10 in regulatory angiogenesis was further validated in IL10-null mouse with UUO. Lenti-Il10 treatment reduced intertubular fibrotic change (45±7%, p<0.05) and attenuated tubular dilatation in UUO (p<0.05, n=30/group). The CD31, an established endothelium marker, was essential to preserve tubular integrity, normally expressed in healthy tubules and abrogated after UUO. IL-10 null mice revealed a lower basal level of CD31 compared to WT mice (Fig.1). In both WT and IL-10 null mice, IL-10 treatment preserved CD31, suggested a potent capability to rescue peritubular capillary (Fig.1).
Conclusion:
Our results indicate that IL-10 can effectively promote angiogenesis in vitro and prevent microvascular rarefaction in vivo. Taken together, our study might lead to a novel therapeutic for the treatment of CKD and associated angiogenic morbidity.
