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Abstract: PO0205

The Effect of Overexpression of Intestinal Alkaline Phosphatase (IAP) on Intestinal Permeability and Renal Failure in Lipopolysaccharide (LPS) Treated IAP Transgenic (IAPTg) Mice

Session Information

  • AKI Mechanisms - 2
    October 22, 2020 | Location: On-Demand
    Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Ghosh, Siddhartha S., Virginia Commonwealth University, Richmond, Virginia, United States
  • Mullaly, Austin J., Virginia Commonwealth University, Richmond, Virginia, United States
  • Ghosh, Shobha, Virginia Commonwealth University, Richmond, Virginia, United States
  • Gehr, Todd W., Virginia Commonwealth University, Richmond, Virginia, United States
Background

LPS associated sepsis is known to cause intestinal dysfunction in septic AKI. IAP is known to dephosphorylate LPS and render it inactive. We generated IAPTg mice who overexpress human IAP. We hypothesized that if IAPTg mice were subjected to septic AKI their kidney function and intestinal barrier permeability will be better preserved than non-transgenic mice.

Methods

IAPTg mice were developed in C57Bl6 background using human chimeric IAP under the control of villin promoter making them intestine and kidney specific overexpressing IAP. LPS (10 mg/Kg) was given to IAPTg (IAPTg+LPS) and C57Bl6 (C5+LPS) to induce septic AKI. The control IAPTg (IAPTg-LPS) and C57Bl6 (C5-LPS) received saline. FITC-Dextran (FD) was gavaged 2 hours before sacrifice to measure intestinal permeability. Blood, intestine (duodenum, jejunum, ileum), and colon were harvested for biochemical and immunoblot analysis.

Results

Serum urea and creatinine of IAPTg mice were 0.6 mg/dl and 65 mg/dl respectively which were 2 and 1.5 fold lower than C5+LPS mice (p<0.05). Serum FD levels of IAPTg+LPS (1.2± 0.1 ng/µl) were 2.5 fold lower than C5+LPS (p<0.05) suggesting improved intestinal integrity. Expression of tight junction protein (ZO-1), pro-apoptotic proteins (Caspase3, Bax), antiapoptotic protein Bcl2 in the colon, and intestine was measured by immunoblot. ZO-1 expression in the intestine and colon of C5+LPS was significantly lower than IAPTg+LPS (p<0.05) and the controls (p<0.01). Expression of intestinal and colon caspase 3 in the IAPTg was 4 fold lower than C5+LPS (p<0.01). Intestinal and colon Bax of IAPTG+LPS were lower and Bcl2 higher than C5+LPS (p<0.05). Apoptotic markers of IAPTg+LPS were not significantly different from the control suggesting low apoptosis in IAPTg. Plasma TNFα and IL-6 levels of IAPTg+LPS were 70±20 and 95+26 pg/ml respectively which were about 1.5 fold lower than C5+LPS (p<0.05) suggesting decreased inflammation in transgenic mice.

Conclusion

Improved ZO-1 expression probably due to reduced apoptosis decreases intestinal permeability in transgenic mice subjected to endotoxemia. This can prevent leakage of bacterial contents from the gut and result in improved renal function and decreased inflammation, as evidenced by decreased plasma cytokines, in IAPTg group.

Funding

  • Private Foundation Support