RESUMEN
The renin-angiotensin-aldosterone system (RAAS) is an important pathway that contributes to the pathophysiology of acute liver injury due to paracetamol toxicity. Omapatrilat, a RAAS-acting agent, inhibits both angiotensin converting enzyme (ACE) and neprilysin/neutral endopeptidase (NEP). The aim of the present study was to investigate the hepatoprotective effects of omapatrilat and examine the role of ACE/NEP pathway on the physiopathology of paracetamol toxicity. A total of 56 BALB/c mice were separated into seven groups: Control, 40 mg/kg omapatrilat only, 400 mg/kg paracetamol only, paracetamol and 140 mg/kg N-acetylcysteine and three groups with paracetamol and 10-40 mg/kg omapatrilat. Blood and liver tissue samples were studied through histopathological imaging, alanine transaminase (ALT) and aspartate transaminase (AST) liver function tests and oxidant/antioxidant biomarker measurements including superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA). ACE and NEP activities were also measured. Histopathological analysis revealed that paracetamol toxicity resulted in a number of apoptotic and necrotic cells in liver tissue samples. By contrast, with 40 mg/kg omapatrilat administration in toxicity-induced mice, hepatocytes were significantly improved and exhibited similar appearance to the control group. Biochemical measurements also supported these histopathological results. Omapatrilat pretreatment provided a dose-dependent reduction in oxidative stress and reversed paracetamol toxicity indications by reducing ALT and AST activities, increasing SOD activity and GSH levels and reducing MDA levels. Dose-dependent increase of ACE and NEP enzymes in omapatrilat groups was also observed. The results demonstrated promotion of antioxidant activity by omapatrilat and suppression of oxidative stress associated with acute liver injury. These findings revealed the potential role of ACE/NEP pathway in paracetamol toxicity and hepatoprotective effects of omapatrilat against oxidative stress.
RESUMEN
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.
