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Kidney Week

Abstract: PO0169

Treprostinil Inhibits Mitochondria-Mediated Apoptosis During Renal Ischemia-Reperfusion Injury in Rats

Session Information

  • AKI Mechanisms - 1
    October 22, 2020 | Location: On-Demand
    Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Ding, Meiwen, University of Rhode Island, Kingston, Rhode Island, United States
  • Tolbert, Evelyn, Lifespan Health System, Providence, Rhode Island, United States
  • Birkenbach, Mark, Lifespan Health System, Providence, Rhode Island, United States
  • Gohh, Reginald Y., Lifespan Health System, Providence, Rhode Island, United States
  • Akhlaghi, Fatemeh, University of Rhode Island, Kingston, Rhode Island, United States
  • Ghonem, Nisanne S., University of Rhode Island, Kingston, Rhode Island, United States
Background

Renal ischemia-reperfusion (I/R) injury is a major factor that contributes to acute kidney injury, which is associated with high morbidity and mortality. Renal I/R injury compromises mitochondrial structure and function, further exacerbating renal tubular injury. Currently, there is no treatment for I/R injury available. We recently demonstrated the efficacy of treprostinil (Remodulin®), an FDA-approved prostacyclin analog, in reducing acute kidney injury during bilateral rat renal I/R injury. This study investigates the role of treprostinil in reducing mitochondria-mediated apoptosis during rat renal I/R injury.

Methods

Male Sprague Dawley rats were randomly assigned to groups: control, sham, I/R-placebo or I/R-treprostinil and subjected to 45 minutes of bilateral renal ischemia followed by 1-72 hours reperfusion. Placebo or treprostinil (100 ng/kg/min) was administered subcutaneously via an osmic minipump. Blood and kidney tissue were collected for analysis.

Results

Treprostinil significantly reduced peak elevated SCr vs. placebo (0.6 ± 0.05 vs. 2.1 ± 0.2 mg/dl, p<0.001) at 24-hour post-reperfusion. Treprostinil also prevented I/R-mediated renal apoptosis at 6-hour post-reperfusion vs. placebo (1.0 ± 0.01 vs. 1.4 ± 0.01, p<0.001) relative to control, determined by TUNEL assay. Mitochondrial DNA (mtDNA) copy number was reduced by 23% in I/R-placebo group (p=0.067) from control, starting by 1-hour post-reperfusion. In contrast, treprostinil preserved mtDNA content to control levels (p<0.01). In addition, placebo increased cytochrome c release into cytosol by 2.4-fold vs.control (p<0.05) at 1-hour post-reperfusion, which treprostinil prevented. Non-targeted semi-quantitative proteomics data using SWATH-MS show decreased renal ATP levels in placebo, which were restored by treprostinil to that of control at 6-hour post-reperfusion (p<0.05).

Conclusion

Our results demonstrate that treprostinil reduces mitochondrial-mediated renal apoptosis, evidenced by reduced cytochrome C release, restored mtDNA copy number and ATP protein concentration to that of control kidney levels, thereby accelerating mitochondrial recovery and protecting renal tubules from I/R-induced apoptosis. These results suggest that treprostinil is a viable therapy to reduce renal I/R injury.

Funding

  • Other NIH Support