The cerebrovascular dilatation effects of olprinone, a phosphodiesterase III inhibitor, in comparison with acetazolamide—a pliot study

Pharmacology of acute mountain sickness: old drugs and newer thinking

Pharmacotherapy in acute mountain sickness (AMS) for the past half century has largely rested on the use of carbonic anhydrase (CA) inhibitors, such as acetazolamide, and corticosteroids, such as dexamethasone. The benefits of CA inhibitors are thought to arise from their known ventilatory stimulation and resultant greater arterial oxygenation from inhibition of renal CA and generation of a mild metabolic acidosis. The benefits of corticosteroids include their broad-based anti-inflammatory and anti-edemagenic effects. What has emerged from more recent work is the strong likelihood that drugs in both classes act on other pathways and signaling beyond their classical actions to prevent and treat AMS. For the CA inhibitors, these include reduction in aquaporin-mediated transmembrane water transport, anti-oxidant actions, vasodilation, and anti-inflammatory effects. In the case of corticosteroids, these include protection against increases in vascular endothelial and blood-brain barrier permeability, suppression of inflammatory cytokines and reactive oxygen species production, and sympatholysis. The loci of action of both classes of drug include the brain, but may also involve the lung as revealed by benefits that arise with selective administration to the lungs by inhalation. Greater understanding of their pluripotent actions and sites of action in AMS may help guide development of better drugs with more selective action and fewer side effects.

Olprinone, a specific phosphodiesterase (PDE)-III inhibitor, reduces the development of multiple organ dysfunction syndrome in mice

Olprinone is a specific phosphodiesterase (PDE)-III inhibitor, which has been found to have anti-inflammatory effects in addition to its main inotropic and peripheral vasodilatory effects. In the present study we investigated the effects of olprinone (0.2mg/kg, i.p.) on the development of zymosan-induced multiple organ failure in mice. Treatment with olprinone attenuated the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan. Olprinone also attenuated the lung, liver and pancreatic injury, renal dysfunction as well as the increased lung and intestine myeloperoxidase (MPO) activity caused by zymosan. Immunohistochemical analysis for inducible nitric oxide synthase (iNOS), nitrotyrosine, poly(ADP-ribose) (PAR), tumor necrosis factor-α (TNF-α) and interleuchin-1β (IL-1β) revealed positive staining in pancreatic and intestinal tissue obtained from zymosan-injected mice. The degree of staining for nitrotyrosine, iNOS, PAR, TNF-α and IL-1β was markedly reduced in tissue sections obtained from zymosan-injected mice, which had received olprinone. In addition, administration of zymosan caused a severe illness in the mice characterized by significant loss of body weight and a 60% of mortality at the end of observation period (7 days). Treatment with olprinone significantly reduced the development of systemic toxicity, loss in body weight and mortality, caused by zymosan. This study provides evidence that olprinone attenuates the degree of zymosan-induced shock in mice.

Effects of olprinone, a phosphodiesterase III inhibitor, on ischemic acute renal failure

OBJECTIVE

Renal ischemic reperfusion injury (IRI) is unavoidable and is still one of the major problems in renal transplantation. The aim of this study was to investigate the effects of olprinone, a phosphodiesterase III inhibitor, on renal IRI.

METHODS

After a right nephrectomy, renal IRI was induced in rats. Olprinone was given in two different ways: sustained systemic administration and transient local administration to the kidney. Control rats were treated with saline. Using a magnifying endoscope, the renal blood flow speed was measured at 23 h after reperfusion. Then, blood samples were collected, and kidney specimens were taken for histological study. In order to study the mechanism, we performed in vitro experiments, using human proximal renal tubular cells (HK-2) incubated with tumor necrosis factor (TNF)-alpha along with olprinone or saline, and interleukin (IL)-8 was measured in the culture supernatant.

RESULTS

In the saline group, the blood flow speed (BFS) was greatly reduced compared to that in normal kidneys. In both olprinone-treated groups, BFS of the renal microcirculation significantly increased, tubular damage and macrophage infiltration attenuated, and renal function greatly improved. Olprinone inhibited the increase in the IL-8 levels resulting from the incubation of HK-2 with TNF-alpha.

CONCLUSIONS

Our study successfully demonstrates that olprinone has renoprotective properties when applied locally as well as systemically. The results suggest that olprinone might be clinically useful in renal transplantation for the donor kidney, the recipient, and even in treating acute renal failure.