Abstract: FR-PO118
Polymyxin and Neomycin (P+N) Attenuates Inflammation and Fibrosis in Unilateral Ureteral Obstructed (UUO) Kidney by Altering Macrophage Phenotype
Session Information
- Molecular Mechanisms of CKD - II
October 26, 2018 | Location: Exhibit Hall, San Diego Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 1903 CKD (Non-Dialysis): Mechanisms
Authors
- Ghosh, Siddhartha S., VCU Medical Ctr, Richmond, Virginia, United States
- Gonzalez, Austin J., Virginia Commonwealth University, Fredericksburg, Virginia, United States
- Krieg, Richard, VCU, Richmond, Virginia, United States
- Gehr, Todd W., Virginia Commonwealth University, Fredericksburg, Virginia, United States
- Ghosh, Shobha, VCU, Richmond, Virginia, United States
Background
Gut bacteria have been shown to modulate inflammation in both acute and chronic kidney injury. P+N are non-absorbable antibiotics that are used to sterilize the gut. UUO mice develop acute inflammation in one kidney after surgery which progresses to fibrosis within 7 days. We wanted to investigate if gut sterilization by P+N can affect inflammation and fibrosis in UUO mice.
Methods
UUO surgery was done by the method adapted from Vanderbilt O’Brien Center. One group of mice was treated with P+N 7 days before UUO. One group was untreated (UT). Control mice did not receive surgery or treatment (C). Mice were sacrificed 3 days (n=5/group) and 10 days (n=5/group) after UUO. Macrophage (Mo) and macrophage phenotype M1 and M2 were determined by flow cytometry. Inflammation markers MCP1, IL1β, and fibrosis marker α-smooth muscle actin (SMA) were assessed by immunoblot. Lipopolysaccharide (LPS) was measured by LAL assay.
Results
3 Days post UUO: P+N treatment did decrease Mo influx in kidney but not Mo phenotype (Table). Only MCP1 increased in UT kidney compared to C, and P+N significantly lowered it (p<0.05). 10 Days post UUO: Although Mo in the kidneys of both groups was significantly higher, UT had more M1 and less M2 compared to P+N (Table). High levels of MCP1, IL-1β and SMA were lowered by P+N. Average plasma LPS in 5 normal mice (C) was 0.8 EU/ml. LPS of UT mice was 3.7±0.32 EU/ml, 3 days after UUO and remained high (3.1±0.3 EU/ml) even after 10 days of UUO. In contrast, LPS levels of P+N group (1.1±.3 EU/ml) after 10 days was not different from group C.
Conclusion
LPS is known to modulate inflammation and Mo phenotype. M1 and M2 phenotypes are known to modulate fibrosis and inflammation respectively. Increased inflammation and fibrosis in UT (10 days) can be attributed to increased M1 and decreased M2. A decrease in inflammatory markers and fibrosis in P+N corresponds to the increased M2 and decreased M1 in this group. P+N can only act at the intestinal level and reduction of systemic LPS by this treatment implies that the gut might be a source of kidney inflammation.
Table
| CD45+CD11b (Mo) | CD45+ CD11b Ly6Chi (M1) | CD45+ CD11b Ly6Clo (M2) | ||||
| UT | P+N | UT | P+N | UT | P+N | |
| 3 day UUO | 30.8± 22.3 | 5.7±0.4* | 73.4±17.9 | 59.7±12.2 | 25.2±17.6 | 39.5±7.5 |
| 10 day UUO | 95.5±3.7 | 83.1±11.3 | 82.5±6.7 | 61.3±17.4* | 15.5±5.5 | 36.9±10.5* |
*p<0.05 compared to UT