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Nitric oxide production and inducible nitric oxide synthase expression in peritoneal macrophages of cirrhotic
W Jiménez1, J Ros, M Morales-Ruiz
1Hormonal Laboratory, Hospital Clínic Universitari and Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain. wjimenez@medicina.ub.es
Abstract:
The present study assessed whether peritoneal macrophages isolated from cirrhotic patients produce nitric oxide (NO) and express NO synthase type II (NOS II) mRNA and protein. Patients with cirrhosis and ascites without peritonitis or with unresolved or resolved spontaneous bacterial peritonitis (SBP) were studied. Following paracentesis, ascites NO(2)(-) + NO(3)(-) content (NOx) was measured. Peritoneal macrophages from ascites were seeded on well plates, and NO(2)(-) in the medium was determined. NOx was higher in patients with unresolved or resolved SBP than in cirrhotic patients without peritonitis. Macrophages of patients with SBP or resolved SBP produced NO(2)(-) after 30 hours in culture, but those obtained from patients without peritonitis did not. Reverse-transcription polymerase chain reaction (RT-PCR) and immunocytochemical analysis revealed the presence of a clear signal for NOS II mRNA and protein in macrophages of SBP patients, regardless of whether or not the infection subsided. Therefore, peritoneal macrophages isolated from cirrhotic patients with unresolved or resolved SBP produce NO and express the NOS II mRNA and protein, suggesting that NOS II may contribute to the control of SBP, or to its associated pathology, in human cirrhosis.
Insights
Cirrhotic patients with spontaneous bacterial peritonitis (SBP) show peritoneal macrophages producing nitric oxide (NO) and expressing NO synthase type II (NOS II). This suggests NOS II
Area of Science:
- Immunology
- Gastroenterology
- Cell Biology
Background:
- Cirrhosis is often complicated by spontaneous bacterial peritonitis (SBP).
- The role of peritoneal macrophages in SBP pathogenesis in cirrhosis is not fully understood.
- Nitric oxide (NO) and its synthase enzymes are implicated in inflammatory responses.
Purpose of the Study:
- To investigate nitric oxide (NO) production and NO synthase type II (NOS II) expression in peritoneal macrophages from cirrhotic patients.
- To determine if SBP influences these parameters.
Main Methods:
- Peritoneal macrophages were isolated from cirrhotic patients with and without SBP (unresolved or resolved).
- Ascites levels of nitrite/nitrate (NOx) were measured.
- Macrophage nitric oxide production was assessed in vitro.
- NOS II mRNA and protein expression were analyzed using RT-PCR and immunocytochemistry.
Main Results:
- Ascites NOx levels were higher in patients with SBP compared to those without.
- Macrophages from patients with SBP (resolved or unresolved) produced NO in culture, unlike those from non-SBP patients.
- Macrophages from SBP patients consistently expressed NOS II mRNA and protein.
Conclusions:
- Peritoneal macrophages from cirrhotic patients with SBP produce NO and express NOS II.
- NOS II expression in macrophages may play a role in controlling SBP or its associated pathology in human cirrhosis.