Possible contribution of the neprilysin/ACE pathway to sepsis in mice.

AIM: Omapatrilat is an antagonist of angiotensin-converting (ACE) and neprilysin-neuropeptidase (NEP) enzymes. The aim of our study is to show that omapatrilat may have beneficial effects as a treatment for polymicrobial sepsis.

MAIN METHODS: A cecal ligation and puncture (CLP) sepsis model was used to evaluate 10 and 20 mg/kg doses of omapatrilat in mice (n = 30) fasted for 12 h. The lungs were removed 12 h after CLP, and lung levels of cytokines (tumor necrosis factor-alpha [TNF-α], interleukin-6 [IL-6], NF-κB), iNOS and eNOS mRNA expression, GSH and MDA levels, and ACE and NEP activities were determined. Histopathological examinations were also performed.

KEY FINDINGS: Omapatrilat treatment provided a dose-dependent reduction in oxidative stress and inflammatory parameters in lung tissues. Omapatrilat administration decreased lung iNOS and eNOS mRNA levels at 20 mg/kg dose. Histopathological analysis revealed a decline in the thickening and edema areas in the alveolar septa in the Sepsis+OMA20 group.

SIGNIFICANCE: Omapatrilat, a dual ACE and NEP inhibitor, protected lung tissue from sepsis damage by reducing ACE and NEP activities, by decreasing the mRNA expression levels of pro-inflammatory cytokines (TNF-α, IL-6, and NF-κB), by suppressing leukocyte infiltration and edema, by restoring iNOS and eNOS levels, and by restoring SOD activity and GSH and MDA levels, thereby reducing oxidative stress.