The effects of the phosphodiesterase inhibitor olprinone on global cerebral ischemia

Toll-like receptor 3 acts as a suppressor gene in breast cancer initiation and progression: a two-stage association study and functional investigation

Toll-like receptor 3 (TLR3) is a receptor recognizing double-stranded RNA (dsRNA) from viruses as well as from lytic mammalian cells. In the present study, we performed a two-stage association study (n = 3,551) and found that the minor alleles of two SNPs (the T-allele of rs5743312 and the T-allele of rs3775296) conferred increased risks of breast cancer incidence. The adjusted odds ratios (ORs) were 2.281 (P = 7.01 × 10-5) and 2.086 (P = 8.69 × 10-5), respectively. Specifically, the susceptibility variants within TLR3 were significantly associated with larger tumor size (adjusted P-values: 0.004 for rs5743312 and 0.004 for rs3775296). Furthermore, we investigated the biological function of the TLR3 protein in breast cancer cell lines. Notably, the stable expression of TLR3 directly inhibited cell proliferation both in vitro and in vivo. We also verified that TLR3 conferred less invasive phenotypes on breast cancer cells by regulating the mRNA expression of a panel of genes. TLR3-mediated inhibition of proliferation was caused by downregulation of the EGFR/PI3K/AKT pathway. In summary, our findings strongly suggest that common genetic changes in the TLR3 gene may influence breast cancer susceptibility and development, and TLR3 plays a negative regulatory role in the initiation and progression of human breast cancer cells, at least in part by downregulating the EGFR/PI3K/AKT pathway.

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/.

Effects of chronic treatment with cilostazol, a phosphodiesterase 3 inhibitor, on female rat bladder in a partial bladder outlet obstruction model

OBJECTIVE

To investigate whether bladder dysfunction after bladder outlet obstruction (BOO) could be altered by treatment with cilostazol, a phosphodiesterase 3 inhibitor (PDE3i).

METHODS

Twelve-week-old female Sprague-Dawley rats were divided into 5 groups: groups 1 and 2, sham-operated rats and groups 3-5, BOO rats. Group 1 and 3 rats were given normal diet, group 2 and 5 rats were given high-dose PDE3i diet, and group 4 rats were given low-dose PDE3i diet. PDE3i was given within diet from the day of surgery. Four weeks after BOO, the bladder was excised and dissected into 4 longitudinal strips for isometric organ-bath assay. Contractile responses of bladder strips to electrical field stimulation (EFS), carbachol, and potassium chloride (KCl) were determined for each group.

RESULTS

BOO induced a significant increase in bladder weight in groups 3-5 compared with groups 1 and 2. PDE3i treatment did not affect bladder weight in sham or BOO rats. Contractile forces in response to EFS, carbachol, and KCl in group 3 were about 20%-40% of those in group 1. Contractile responses to EFS or KCl in PDE3i-treated BOO rats were not significantly different from those in group 3. Only high dose of PDE3i treatment in BOO rats caused a statistically significant increase in the response to carbachol compared with group 3.

CONCLUSION

PDE3i has a small but significant protective effect on the contractile dysfunction induced by a 4-week BOO in rats, although the increase in bladder mass was not altered. PDE3i could be a useful protection against contractile dysfunction of the obstructed bladder.

Olprinone attenuates the acute inflammatory response and apoptosis after spinal cord trauma in mice

Background

Olprinone hydrochloride is a newly developed compound that selectively inhibits PDE type III and is characterized by several properties, including positive inotropic effects, peripheral vasodilatory effects, and a bronchodilator effect. In clinical settings, olprinone is commonly used to treat congestive cardiac failure, due to its inotropic and vasodilating effects. The mechanism of these cardiac effects is attributed to increased cellular concentrations of cAMP. The aim of the present study was to evaluate the pharmacological action of olprinone on the secondary damage in experimental spinal cord injury (SCI) in mice.

Methodology/Principal Findings

Traumatic SCI is characterized by an immediate, irreversible loss of tissue at the lesion site, as well as a secondary expansion of tissue damage over time. Although secondary injury should be preventable, no effective treatment options currently exist for patients with SCI. Spinal cord trauma was induced in mice by the application of vascular clips (force of 24 g) to the dura via a four-level T5–T8 laminectomy. SCI in mice resulted in severe trauma characterized by edema, neutrophil infiltration, and production of inflammatory mediators, tissue damage, apoptosis, and locomotor disturbance. Olprinone treatment (0.2 mg/kg, i.p.) 1 and 6 h after the SCI significantly reduced: (1) the degree of spinal cord inflammation and tissue injury (histological score), (2) neutrophil infiltration (myeloperoxidase activity), (3) nitrotyrosine formation, (4) pro-inflammatory cytokines, (5) NF-κB expression, (6) p-ERK1/2 and p38 expression and (7) apoptosis (TUNEL staining, FAS ligand, Bax and Bcl-2 expression). Moreover, olprinone significantly ameliorated the recovery of hind-limb function (evaluated by motor recovery score).

Conclusions/Significance

Taken together, our results clearly demonstrate that olprinone treatment reduces the development of inflammation and tissue injury associated with spinal cord trauma.