Pretreatment with olprinone hydrochloride, a phosphodiesterase III inhibitor, attenuates lipopolysaccharide-induced lung injury via an anti-inflammatory effect

The need for inhaled phosphodiesterase inhibitors in chronic obstructive pulmonary disease

INTRODUCTION

The therapeutic implications of phosphodiesterase (PDE) inhibitors have attracted interest because PDEs are regarded as an intracellular target to be exploited for therapeutic advancements in the treatment of COPD. At present, the only approved approach for the treatment of COPD with PDE inhibitors is the use of an oral PDE4 inhibitor. However, this treatment is not widely employed, primarily due to the narrow therapeutic index associated with oral PDE4 inhibitors, which significantly limits the tolerable dose. The inhalation route represents a viable alternative to the oral route for improving the therapeutic index of PDE4 inhibitors.

AREAS COVERED

The development of inhaled PDE4 inhibitors, with a focus on tanimilast and ensifentrine, the latter of which is a dual PDE3/PDE4 inhibitor.

EXPERT OPINION

The inhalation route offers several advantages regarding the delivery of PDE inhibitors for the management of COPD. Tanimilast and ensifentrine have been shown to improve lung function, reduce exacerbations and enhance quality of life in COPD patients. However, it has not yet been determined which type of COPD patient might benefit more from inhaled PDE4 inhibitors, and it remains unclear whether concomitant inhibition of PDE3 and PDE4 confers a significant benefit compared to blocking PDE4 alone in COPD.

Novel mechanism of cyclic nucleotide crosstalk mediated by PKG-dependent proteasomal degradation of the Hsp90 client protein phosphodiesterase 3A

Endothelial cAMP-specific phosphodiesterase PDE3A is one of the major negative regulators of the endothelial barrier function in acute lung injury models. However, the mechanisms underlying its regulation still need to be fully resolved. We show here that the PDE3A is a newly described client of the molecular chaperone heat shock protein 90 (hsp90). In endothelial cells (ECs), hsp90 inhibition by geldanamycin (GA) led to a disruption of the hsp90/PDE3A complex, followed by a significant decrease in PDE3A protein levels. The decrease in PDE3A protein levels was ubiquitin-proteasome-dependent and required the activity of the E3 ubiquitin ligase C terminus of Hsc70-interacting protein. GA treatment also enhanced the association of PDE3A with hsp70, which partially prevented PDE3A degradation. GA-induced decreases in PDE3A protein levels correlated with decreased PDE3 activity and increased cAMP levels in EC. We also demonstrated that protein kinase G-dependent phosphorylation of PDE3A at Ser654 can signal the dissociation of PDE3A from hsp90 and PDE3A degradation. This was confirmed by endogenous PDE3A phosphorylation and degradation in 8-Br-cGMP- or 8-CPT-cGMP- and Bay 41-8543-stimulated EC and comparisons of WT- and phospho-mimic S654D mutant PDE3A protein stability in transiently transfected HEK293 cells. In conclusion, we have identified a new mechanism of PDE3A regulation mediated by the ubiquitin-proteasome system. Further, the degradation of PDE3A is controlled by the phosphorylation of S654 and the interaction with hsp90. We speculate that targeting the PDE3A/hsp90 complex could be a therapeutic approach for acute lung injury.

Phosphodiesterase Inhibitors in Acute Lung Injury: What Are the Perspectives?

Despite progress in understanding the pathophysiology of acute lung damage, currently approved treatment possibilities are limited to lung-protective ventilation, prone positioning, and supportive interventions. Various pharmacological approaches have also been tested, with neuromuscular blockers and corticosteroids considered as the most promising. However, inhibitors of phosphodiesterases (PDEs) also exert a broad spectrum of favorable effects potentially beneficial in acute lung damage. This article reviews pharmacological action and therapeutical potential of nonselective and selective PDE inhibitors and summarizes the results from available studies focused on the use of PDE inhibitors in animal models and clinical studies, including their adverse effects. The data suggest that xanthines as representatives of nonselective PDE inhibitors may reduce acute lung damage, and decrease mortality and length of hospital stay. Various (selective) PDE3, PDE4, and PDE5 inhibitors have also demonstrated stabilization of the pulmonary epithelial-endothelial barrier and reduction the sepsis- and inflammation-increased microvascular permeability, and suppression of the production of inflammatory mediators, which finally resulted in improved oxygenation and ventilatory parameters. However, the current lack of sufficient clinical evidence limits their recommendation for a broader use. A separate chapter focuses on involvement of cyclic adenosine monophosphate (cAMP) and PDE-related changes in its metabolism in association with coronavirus disease 2019 (COVID-19). The chapter illuminates perspectives of the use of PDE inhibitors as an add-on treatment based on actual experimental and clinical trials with preliminary data suggesting their potential benefit.

A Double-Blind Placebo-Controlled Study of the Effects of Olprinone, a Specific Phosphodiesterase III Inhibitor, for Preventing Postoperative Atrial Fibrillation in Patients Undergoing Pulmonary Resection for Lung Cancer

BACKGROUND

We previously reported that patients with elevated preoperative B-type natriuretic peptide (BNP) levels have an increased risk for postoperative atrial fibrillation following lung cancer surgery. The present study evaluated whether the specific phosphodiesterase III inhibitor olprinone can reduce the incidence of postoperative atrial fibrillation in patients with elevated BNP levels undergoing pulmonary resection for lung cancer.

METHODS

A prospective randomized study was conducted with 40 patients who had elevated preoperative BNP levels (≥ 30 pg/mL) and underwent scheduled lung cancer surgery. All patients were in sinus rhythm at surgery. Low-dose olprinone or placebo was continuously infused for 24 h and started just before anesthesia induction. The primary end point was the incidence of postoperative atrial fibrillation. The secondary end points were perioperative hemodynamics and levels of BNP, WBC counts, and C-reactive protein.

RESULTS

The incidence of postoperative atrial fibrillation was significantly lower in the olprinone group than in the placebo group (10% vs 60%, P < .001). Patients in the olprinone group showed significantly lower BNP, WBC counts, and C-reactive protein levels after surgery.

CONCLUSIONS

Continuous infusion of olprinone during lung cancer surgery was safe and reduced the incidence of postoperative atrial fibrillation following pulmonary resection in patients with elevated preoperative BNP levels.

TRIAL REGISTRY

Japan Primary Registries Network; No.: JPRN-UMIN2404; URL: http://www.umin.ac.jp/ctr/.

Olprinone and colforsin daropate alleviate septic lung inflammation and apoptosis through CREB-independent activation of the Akt pathway

Olprinone, a specific phosphodiesterase III inhibitor, and corforsin daropate, a direct adenylate cyclase activator, are now being used in critical conditions. We investigated whether their therapeutic use provides protection against septic acute lung injury (ALI) and mortality. Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in BALB/c mice. Olprinone or colforsin daropate was continuously given through an osmotic pump that was implanted into the peritoneal cavity immediately following CLP. These treatments prevented the ALI development in CLP mice, as indicated by the findings that severe hypoxemia, increased pulmonary vascular permeability, and histological lung damage were strikingly remedied. Furthermore, continued administration of olprinone or colforsin daropate suppressed apoptosis induction in septic lungs and improved the survival of CLP mice. Olprinone and corforsin daropate enhanced Akt phosphorylation in septic lungs. Wortmannin, which inhibits the Akt upstream regulator phosphatidylinositol 3-kinase, abrogated the protective effects of olprinone and corforsin daropate on sepsis-associated lung inflammation and apoptosis. In vivo transfection of cyclic AMP response element binding protein (CREB) decoy oligodeoxynucleotide failed to negate the abilities of these agents to increase Akt phosphorylation and to inhibit IκBα degradation in septic lungs. These results demonstrate for the first time that CREB-independent Akt-mediated signaling is a critical mechanism contributing to the therapeutic effects of olprinone and corforsin daropate on septic ALI. Moreover, our data also suggest that these cyclic AMP-related agents, by blocking both nuclear factor-κB activation and apoptosis induction, may represent an effective therapeutic approach to the treatment of the septic syndrome.

Selective phosphodiesterase 3 inhibitor olprinone attenuates meconium-induced oxidative lung injury

Since inflammation and oxidation play a key role in the pathophysiology of neonatal meconium aspiration syndrome, various anti-inflammatory drugs have been tested in the treatment. This study evaluated whether the phosphodiesterase (PDE) 3 inhibitor olprinone can alleviate meconium-induced inflammation and oxidative lung injury. Oxygen-ventilated rabbits intratracheally received 4 ml/kg of meconium (25 mg/ml) or saline. Thirty minutes after meconium/saline instillation, meconium-instilled animals were treated by intravenous olprinone (0.2 mg/kg) or were left without treatment. All animals were oxygen-ventilated for an additional 5 h. A bronchoalveolar lavage (BAL) of the left lungs was performed and differential leukocyte count in the sediment was estimated. The right lungs were used to determine lung edema by wet/dry weight ratio, as well as to detect oxidative damage to the lungs. In the lung tissue homogenate, total antioxidant status (TAS) was determined. In isolated lung mitochondria, the thiol group content, conjugated dienes, thiobarbituric acid-reactive substances (TBARS), dityrosine, lysine-lipid peroxidation products, and activity of cytochrome c oxidase (COX) were estimated. To evaluate the effects of meconium instillation and olprinone treatment on the systemic level, TBARS and TAS were determined in the blood plasma, as well. Meconium instillation increased the relative numbers of neutrophils and eosinophils in the BAL fluid, increased edema formation and concentrations of oxidation markers, and decreased TAS. Treatment with olprinone reduced the numbers of polymorphonuclears in the BAL fluid, decreased the formation of most oxidation markers in the lungs, reduced lung edema and prevented a decrease in TAS in the lung homogenate compared to non-treated animals. In the blood plasma, olprinone decreased TBARS and increased TAS compared to the non-treated group. Conclusion, the selective PDE3 inhibitor olprinone has shown potent antioxidative and anti-inflammatory effects in the meconium-induced oxidative lung injury.

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.

Olprinone, a PDE3 inhibitor, modulates the inflammation associated with myocardial ischemia-reperfusion injury in rats

Coronary ischemia and subsequent reperfusion result in deleterious effects, one of the principal ones being vascular and myocardial inflammation. Olprinone hydrochloride, a specific phosphodiesterase III inhibitor, has anti-inflammatory effects in addition to its inotropic and vasodilator effects. The purpose of this study was to examine the beneficial effects of olprinone on myocardial ischemia-reperfusion injury. Myocardial ischemia-reperfusion injury was caused by clamping the LAD (left anterior descending) coronary artery for 25 min followed by a release of the clamp allowing reperfusion for 1 h. Olprinone i.p. (0.2 mg/kg, i.p.) was administrated 15 min after ischemia. The olprinone administration significantly reduced the: (1) histological evidence of myocardial injury, (2) pro-inflammatory cytokines: tumor necrosis factor-α (TNF-α) and Interleukin-1β (IL-1β), (3) adhesion molecules: Inter-Cellular Adhesion Molecule 1 (ICAM-1) and P-Selectin, (4) nitrotyrosine formation, (5) nuclear factor kappa-B (NF-κB) expression, (6) Poly (ADP-ribose) (PAR) formation, and (7) apoptosis (Bax, Bcl-2, Fas-L and terminal deoxynucleotidyl transferase-mediated UTP end labeling (TUNEL). Based on these findings this study provides the evidence that treatment with olprinone ameliorated the inflammatory process associated with myocardial ischemia-reperfusion in rats and suggests that this drug may have potential in the treatment of various ischemia and reperfusion diseases.

The effects of the phosphodiesterase inhibitor olprinone on global cerebral ischemia

BACKGROUND

The phosphodiesterase III inhibitor olprinone has been confirmed to improve myocardial function and increase cerebral blood flow; therefore, if olprinone exerts direct neuroprotective effects against global cerebral ischemia to the same degree as cilostazol, olprinone could be useful for cerebral resuscitation after cardiac arrest. We examined whether olprinone directly protected neuronal cells from global cerebral ischemia both in vivo and in vitro.

METHODS

In a rat model of 10-minute global cerebral ischemia induced by 4-vessel occlusion, 0.3, 3, or 30 microg x kg(-1) x min(-1) olprinone or saline was infused for a periischemic period of 40 minutes (n = 6 for each group). Hippocampal CA1 neuronal cells were then counted 3 days after reperfusion, and the phosphorylation of cyclic adenosine 3'5'-monophosphate response element-binding protein was examined using Western blotting analyses of specimens obtained 15 minutes after reperfusion. In vitro, cultured cerebral neurons were exposed to 4 hours of hypoxia and glucose deprivation and then 24 hours of recovery in the absence or presence of olprinone (10(-11)-10(-5) mol x L(-1)). Cell viability was measured using the Cell Counting Kit-8 (Dojindo Molecular Technologies, Gaithersburg, MD).

RESULTS

In the rat model of global ischemia, the number of surviving CA1 neurons counted under a microscopic field in the 30 microg x kg(-1) x min(-1) olprinone-treated group (49.9 +/- 9.2) was significantly higher than that in the saline infusion control group (7.2 +/- 3.4), and olprinone treatment increased the phosphorylation of cyclic adenosine 3'5'-monophosphate response element-binding protein. The survival fraction of the neuronal cells cultured in the presence of olprinone was also significantly higher than that of cells cultured in the absence of olprinone in a dose-dependent manner.

CONCLUSIONS

Our study successfully demonstrated, for the first time, that olprinone had a protective effect on neuronal cells in vitro and in vivo, especially against global cerebral ischemia. These results suggest that olprinone might be useful for the treatment of patients experiencing global cerebral ischemia.