Angiotensin-converting enzyme inhibitors attenuate propofol-induced pro-oxidative and antifibrinolytic effect in human endothelial cells

Introduction:

The aim of this study was to investigate the effects of plasma and tissue angiotensin-converting enzyme inhibitors (ACE-Is) against propofol-induced endothelial dysfunction and to elucidate the involved mechanisms in vitro.

Materials and methods:

We examined the effects of propofol (50 μM), quinaprilat and enalaprilat (10⁻⁵ M) on fibrinolysis (t-PA, PAI-1, TAFI antigen levels), oxidative stress parameters (H₂O₂ and MDA antigen levels and SOD and NADPH oxidase mRNA levels) and nitric oxide bioavailability (NO₂/NO₃ concentration and NOS expression at the level of mRNA) in human umbilical vein endothelial cells (HUVECs).

Results:

We found that both ACE-Is promoted similar endothelial fibrinolytic properties and decreased oxidative stress in vitro. Propofol alone increased the release of antifibrinolytic and pro-oxidative factors from the endothelium and increased mRNA iNOS expression. We also found that the incubation of HUVECs in the presence of propofol following ACE-Is pre-incubation caused weakness of the antifibrinolytic and pro-oxidative potential of propofol and this effect was similar after both ACE-Is.

Conclusions:

This observation suggests that the studied ACE-Is exerted protective effects against endothelial cell dysfunction caused by propofol, independently of hemodynamics.

Quinapril and its metabolite quinaprilat in human milk

AIMS

To measure the milk to plasma ratio (M/P) of quinapril and its active metabolite quinaprilat in lactating mothers and to assess likely infant exposure.

METHODS

A single dose of quinapril 20 mg was administered to six healthy mothers who had been breastfeeding their infants for at least 2 weeks. Blood was sampled for the measurement of quinapril and quinaprilat at 0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 16 and 24 h. Milk was collected for measurement of quinapril and quinaprilat concentrations over the periods -4-0, 0-4, 4-8, 8-12, 12-18, 18-24 h. The areas under the plasma and milk concentration-time curves were estimated and an M/P ratio derived for both quinapril and quinaprilat.

RESULTS

The M/P ratio for quinapril was 0.12 (95% CI 0.09,0.14). No quinapril was detected in milk after 4 h. No quinaprilat was detected in any of the milk samples. The estimated 'dose' of quinapril that would be received by the infant was 1.6% (95% CI 1.0,2.2) of the maternal dose, adjusted for respective weights.

CONCLUSIONS

Quinapril appears to be 'safe' during breastfeeding according to conventional criteria, although as always, the risk:benefit ratio should be considered when it is to be given to a nursing mother.