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Methylene blue improves hemodynamic shock but increases lipoperoxidation in severe acute pancreatitis pig model
Roberto Ferreira Meirelles1, Reginaldo Ceneviva, Fernanda Viaro
1Department of Surgery and Anatomy, Ribeirão Preto Faculty of Medicine, University of São Paulo, SP, Brazil. roberto.meirelles@hcnet.usp.br
Purpose:
Study hemodynamic pattern and lipoperoxidation during methylene blue (MB) treatment on taurocholate - enterokinase induced acute pancreatitis (AP).
Methods:
Thirty pigs were equally divided in control group; MB group; AP group; MB previous AP group; and MB after 90 min of induced AP group. MB was given iv in a bolus dose (2 mg.kg-1) followed by maintenance dose (2 mg.kg-1.h-1). Hemodynamic parameters were recorded continuously during 180 min by Swan-Ganz catheter. Blood samples were taken every 60 min to determine arterial and venous nitrate, malondialdehyde (MDA) and amylase. Pancreatic tissue was removed for histopathologic study.
Results:
In AP group MBP and CO decreased over time 33% (p<0.05) and 52% (p<0.05), respectively. In MB previous induced-AP group, there was 70 minutes delay (p<0.05) to decrease MBP and CO. In MB group arterial and venous nitrite decreased (p<0.05) over time. MB infusion increased (p>0.05) serum MDA when associated to AP. After induced AP, MB did not reverse MBP and CO decrease. There was no difference in serum amylase and necro-hemorrhagic findings with MB treatment.
Conclusions:
In this taurocholate-induced AP model MB treatment delayed hemodynamic shock and decreases serum nitrate levels but increases serum MDA levels. No volemic replacement was done and it may have been a mitigated factor to a poor tissue perfusion and impairment microcirculation. Further investigations are needed to elucidate MB treatment role during AP treatment.
Insights
Methylene blue (MB) delayed shock in acute pancreatitis (AP) pigs but increased lipid peroxidation. MB also reduced nitrate levels, but did not improve pancreatic damage or reverse hemodynamic decline.
Area of Science:
- Gastroenterology and Hepatology
- Critical Care Medicine
- Pharmacology
Background:
- Acute pancreatitis (AP) is a severe inflammatory condition with significant mortality.
- Hemodynamic instability and organ dysfunction are key complications of AP.
- Lipid peroxidation plays a role in AP pathogenesis.
Purpose of the Study:
- To investigate the effects of methylene blue (MB) on hemodynamic patterns and lipoperoxidation in a porcine model of acute pancreatitis (AP).
- To assess MB's potential therapeutic role in managing AP-induced complications.
Main Methods:
- A porcine model of AP was induced using taurocholate and enterokinase.
- Thirty pigs were divided into control, MB, AP, and MB-treated AP groups.
- Hemodynamic parameters, serum nitrates, malondialdehyde (MDA), and amylase were monitored. Pancreatic tissue was analyzed histopathologically.
Main Results:
- Methylene blue (MB) administration delayed the onset of decreased mean blood pressure (MBP) and cardiac output (CO) in AP pigs.
- MB treatment led to decreased serum nitrate levels but increased serum malondialdehyde (MDA) levels in AP.
- No significant improvement in serum amylase or pancreatic necro-hemorrhagic findings was observed with MB treatment.
Conclusions:
- Methylene blue (MB) demonstrated a protective effect by delaying hemodynamic shock in this AP model.
- MB treatment influenced biochemical markers, reducing nitrates but increasing lipid peroxidation.
- The study suggests further research is needed to clarify MB's role in AP, considering potential confounding factors like fluid resuscitation.
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