The effects of iloprost on colonic anastomotic healing in rats under obstructive ileus conditions

BACKGROUND

The aim of this study was to investigate the effects of iloprost, on colonic anastomotic healing in rats, under obstructive ileus conditions.

MATERIALS AND METHODS

Eighty male Albino rats were randomized into four groups of 20 animals each. They underwent colonic resection followed by an inverted anastomosis. The rats of group 1 (control) and group 2 (ileus) received 3 mL of saline 0.9% intraperitoneally and those of group 3 (iloprost), and group 4 (ileus + iloprost) iloprost (2 μg/kg of body weight), immediately postoperatively and daily until the day of sacrifice. Each group was further divided into two equal subgroups, depending on the day of sacrifice. The animals of subgroup "a" were sacrificed on the fourth postoperative day, whereas those of "b" on the eighth day. Macroscopic and histologic assessment was performed, whereas anastomotic bursting pressures and the tissue concentrations in hydroxyproline and collagenase I were evaluated.

RESULTS

Means of bursting pressure, neoangiogenesis, fibroblast activity, and hydroxyproline concentration were significantly increased in group 4 compared with group 2. In addition, on the fourth postoperative day, the inflammatory cell infiltration and the collagenase I concentration were significantly decreased in group 4 compared with group 2. Moreover, on the eighth postoperative day, collagen deposition was significantly increased in group 4 compared with group 2.

CONCLUSIONS

Iloprost after intraperitoneal administration reverses the negative effect of obstructive ileus. It promotes not only the angiogenic activity but also collagen formation, resulting in increased bursting pressures on the fourth and eighth postoperative days.

Iloprost for idiopathic pulmonary arterial hypertension

Idiopathic pulmonary arterial hypertension is a rare but serious and life-threatening disease that leads to right heart failure and death within 2.8 years without specific treatment. This review focuses on the stable prostacyclin analog iloprost, its biologic action and pharmacology and, finally, on its clinical development, efficacy and safety in patients with idiopathic pulmonary arterial hypertension, which led to its approval for this indication. Furthermore, this review assesses the role of iloprost compared with other newly developed drugs, such as the endothelin receptor antagonist bosentan and the phosphodiesterase-5 inhibitor sildenafil, as well as other modes of application of prostacyclin and its analogs for the treatment of idiopathic pulmonary arterial hypertension. Based on the different modes of action of these substances, a combination of these treatments could be most promising for the future.

Iloprost inhibits fracture repair in rats

BACKGROUND

Previous studies have shown that prostaglandins (PGs) dramatically stimulate healing processes in bone. However, the effect of prostaglandin I2 (PGI2) on fracture healing remains unclear. To investigate the effect of PGI2, a study on fracture healing process in closed tibia fractures was designed.

METHODS

Thirty-six Sprague-Dawley male rats were randomized into two groups. On the first day, their right tibias were fractured by three-point bending technique. The study group (n = 18) received a single injection of 10 µg/kg iloprost for 5 days, while the control group (n = 18) received saline solution in the same way. On the 7th, 14th and 28th days following the fracture, six rats were sacrificed and their right legs were harvested in each group. The progression of fracture healing was assessed for each specimen by the scores of radiography (by Lane-Sandhu) and histology (by Huo et al).

RESULTS

On the 7th day, the radiographic and histologic scores were equal. On the 14th day radiographic total score was 6 and histologic total score was 23 in the iloprost group, whereas radiographic total score was 11 and histologic total score was 33 in the control group. On the 14th day radiographic and histologic scores were significantly decreased in the iloprost group compared to the control group (P < 0.05). On the 28th day radiographic total score was 12 and histologic total score was 37 in the iloprost group, whereas radiographic total score was 15 and histologic total score was 40 in the control group. On the 28th day although there was a decrease in radiographic and histologic scores of the iloprost group acording to control group, it was not statistically significant (P > 0.05).

CONCLUSION

Iloprost delays fracture healing in early stage in rats.

Prostaglandin I2-IP signalling regulates human Th17 and Treg cell differentiation

Prostaglandin I2 (PGI2) is an important immunoregulatory lipid mediator. In this study, we analysed the effects of the PGI2 analogue (Iloprost) on the differentiation of Th17 cells and Tregs from human naïve CD4(+) T cells. PGI2 receptors (IP) are expressed on human naïve CD4(+) T cells. Via IP binding, the PGI2 analogue decreased the proportion of Tregs and Foxp3 mRNA expression but increased the percentage of Th17 cells, RORC mRNA and IL-17A production. The regulatory effects of Iloprost correlated with elevated intracellular cAMP levels. The effects were mimicked by a cAMP agonist (db-cAMP) but attenuated by a protein kinase A inhibitor (H-89). STAT3 and STAT5 signalling play direct and crucial roles in the development of Th17 and Tregs, respectively. The PGI2 analogue enhanced the activation of STAT3 in response to IL-6, whereas it decreased STAT5 activation in response to IL-2. Moreover, db-cAMP imitated the above effects of Iloprost, which were weakened by H-89. These results demonstrate that the PGI2-IP interaction promoted the phosphorylation of STAT3 and reduced the phosphorylation of STAT5, likely via the upregulation of cAMP-PKA signalling, thus facilitated Th17 differentiation and suppressed Treg differentiation. Together with previous results, these data suggest that prostanoids play an important role in the pathogenesis of autoimmune diseases, such as rheumatoid arthritis.

Acute effects of aerosolized iloprost in COPD related pulmonary hypertension - a randomized controlled crossover trial

Background

Inhaled iloprost potentially improves hemodynamics and gas exchange in patients with chronic obstructive pulmonary disease (COPD) and secondary pulmonary hypertension (PH).

Objectives

To evaluate acute effects of aerosolized iloprost in patients with COPD-associated PH.

Methods

A randomized, double blind, crossover study was conducted in 16 COPD patients with invasively confirmed PH in a single tertiary care center. Each patient received a single dose of 10 µg iloprost (low dose), 20 µg iloprost (high dose) and placebo during distinct study-visits. The primary end-point of the study was exercise capacity as assessed by the six minute walking distance.

Results

Both iloprost doses failed to improve six-minute walking distance (p = 0.36). Low dose iloprost (estimated difference of the means −1.0%, p = 0.035) as well as high dose iloprost (−2.2%, p<0.001) significantly impaired oxygenation at rest. Peak oxygen consumption and carbon dioxide production differed significantly over the three study days (p = 0.002 and p = 0.003, accordingly). As compared to placebo, low dose iloprost was associated with reduced peak oxygen consumption (−76 ml/min, p = 0.002), elevated partial pressure of carbon dioxide (0.27 kPa, p = 0.040) and impaired ventilation during exercise (−3.0l/min, p<0.001).

Conclusions

Improvement of the exercise capacity after iloprost inhalation in patients with COPD-associated mild to moderate PH is very unlikely.

Trial Registration

Controlled-Trials.com ISRCTN61661881

Prostaglandin I(2) analogues enhance already exuberant Th17 cell responses in systemic sclerosis

OBJECTIVE

Among pleiotropic effects, the capacity of prostaglandin I(2) (PGI(2)) analogues to affect adaptive immunity remains poorly characterised. The purpose of this study was to assess whether PGI(2) analogues could affect T helper (Th) cell responses in patients with systemic sclerosis (SSc) and healthy donors (HD).

METHODS

Peripheral blood mononuclear cells (PBMC) were obtained from 33 patients with SSc and 29 HD. Cytokine levels in PBMC and monocyte/CD4 T cell cultures were quantified by immunoassays. The frequencies of interleukin (IL)-17A, IL-22, interferon γ (IFNγ) and IL-4-producing CD4 T cells were assessed by multiparametric flow cytometry. Selective receptor antagonists, cytokine blocking antibodies and signalling protein inhibitors were used to identify the receptors and signalling pathways mediating PGI(2) analogue effects.

RESULTS

Th17 and Th22 cells were more abundant in individuals with SSc than in HD. PGI(2) analogues (iloprost, treprostinil and beraprost) significantly increased IL-17A and IL-22 in vitro while decreasing IFNγ production both in SSc and HD PBMC. These effects relied on the specific expansion of Th17 and Th22 and inhibition of Th1 cells. The enhanced Th17 cell responses depended on increased IL-23 production by monocytes, involved the IP prostacyclin receptor and required protein kinase A activation. Importantly, in vivo administration of iloprost in individuals with SSc presenting with digital ulcers resulted in a significant increase in the frequency of Th17 cells.

CONCLUSIONS

These findings demonstrate that PGI(2) analogues affect Th cell differentiation/expansion programmes, favouring Th17 and inhibiting Th1 cell responses in SSc. The impact of these changes on the disease course needs to be taken into consideration and further exploited to improve SSc.

Prostanoid receptors involved in regulation of the beating rate of neonatal rat cardiomyocytes

Although prostanoids are known to be involved in regulation of the spontaneous beating rate of cultured neonatal rat cardiomyocytes, the various subtypes of prostanoid receptors have not been investigated in detail. In our experiments, prostaglandin (PG)F_2α and prostanoid FP receptor agonists (fluprostenol, latanoprost and cloprostenol) produced a decrease in the beating rate. Two prostanoid IP receptor agonists (iloprost and beraprost) induced first a marked drop in the beating rate and then definitive abrogation of beating. In contrast, the prostanoid DP receptor agonists (PGD₂ and BW245C) and TP receptor agonists (U-46619) produced increases in the beating rate. Sulprostone (a prostanoid EP₁ and EP₃ receptor agonist) induced marked increases in the beating rate, which were suppressed by SC-19220 (a selective prostanoid EP₁ antagonist). Butaprost (a selective prostanoid EP₂ receptor agonist), misoprostol (a prostanoid EP₂ and EP₃ receptor agonist), 11-deoxy-PGE₁ (a prostanoid EP₂, EP₃ and EP₄ receptor agonist) did not alter the beating rate. Our results strongly suggest that prostanoid EP₁ receptors are involved in positive regulation of the beating rate. Prostanoid EP₁ receptor expression was confirmed by western blotting with a selective antibody. Hence, neonatal rat cardiomyocytes express both prostanoid IP and FP receptors (which negatively regulate the spontaneous beating rate) and prostanoid TP, DP₁ and EP₁ receptors (which positively regulate the spontaneous beating rate).

No additive effects of inhaled iloprost and prone positioning on pulmonary hypertension and oxygenation in acute respiratory distress syndrome

BACKGROUND

In acute respiratory distress syndrome (ARDS), pulmonary hypertension is associated with a poor prognosis. Prone position is effective to improve oxygenation whereas inhaled iloprost can treat pulmonary hypertension. However, combination of these interventions has not been examined before. The hypothesis was that this combination had additive effects on oxygenation and pulmonary hemodynamics as compared with each intervention alone.

METHODS

In a prospective, randomized cross-over study, ten pigs were anesthetized, intubated and ventilated with volume controlled ventilation. Carotid, jugular venous and pulmonary artery catheters were inserted. ARDS was induced with oleic acid (0.20 mL/kg). Measurements were repeated in randomized different sequences of prone or supine positions with or without iloprost inhalation (220 ng/kg/min) (four combinations). Systemic and pulmonary arterial pressures; arterial and mixed venous blood gases; and Qs/Qt and the resistances were recorded.

RESULTS

Iloprost decreased pulmonary artery pressures (for MPAP: P=0.034) in both supine (37±10 vs. 31±8 mmHg; P<0.05) and prone positions (38±9 vs. 29±8 mmHg; P<0.05); but did not obtain a significant improvement in oxygenation in both positions. Prone position improved the oxygenation (p<0.0001) compared to supine position in both with (361±140 vs. 183±158 mmHg, P<0.05) or without iloprost application (331±112 vs. 167±117 mmHg, P<0.05); but did not achieve a significant decrease in MPAP.

CONCLUSION

Although iloprost reduced pulmonary arterial pressures, and prone positioning improved oxygenation; there are no additive effects of the combination of both interventions on both parameters. To treat both pulmonary hypertension and hypoxemia, application of iloprost in prone position is suggested.

The prostacyclin agonist iloprost aggravates fibrosis and enhances viral replication in enteroviral myocarditis by modulation of ERK signaling and increase of iNOS expression

Enteroviruses, such as coxsackieviruses of group B (CVB), are able to induce a chronic inflammation of the myocardium, which may finally lead to the loss of functional tissue, remodeling processes and the development of fibrosis, thus affecting the proper contractile function of the heart. In other fibrotic diseases like scleroderma, the prostacyclin agonist iloprost was found to inhibit the extracellular signal-regulated kinase (ERK, p44/42 MAPK), a mitogen-activated protein kinase, and consecutively, the expression of the profibrotic cytokine connective tissue growth factor (CTGF), thereby preventing the development of fibrosis. As CTGF was found to mediate fibrosis in chronic CVB3 myocarditis as well, we evaluated whether the in vivo application of iloprost is capable to reduce the development of ERK/CTGF-mediated fibrosis in enteroviral myocarditis. Unexpectedly, the application of iloprost resulted in a prolonged myocardial inflammation and an aggravated fibrosis and failed to reduce activation of ERK and expression of CTGF at later stages of the disease. In addition, viral replication was found to be increased in iloprost-treated mice. Notably, the expression of cardiac inducible nitric oxide synthase (iNOS), which is known to aggravate myocardial damage in CVB3-infected mice, was strongly enhanced by iloprost. Using cultivated bone marrow macrophages (BMM), we confirmed these results, proving that iloprost potentiates the expression of iNOS mRNA and protein in CVB3-infected and IFN-gamma stimulated BMM. In conclusion, these results suggest a critical reflection of the clinical use of iloprost, especially in patients possibly suffering from an enteroviral myocarditis.

Prostaglandin I2 signaling drives Th17 differentiation and exacerbates experimental autoimmune encephalomyelitis

Background

Prostaglandin I₂ (PGI₂), a lipid mediator currently used in treatment of human disease, is a critical regulator of adaptive immune responses. Although PGI₂ signaling suppressed Th1 and Th2 immune responses, the role of PGI₂ in Th17 differentiation is not known.

Methodology/Principal Findings

In mouse CD4⁺CD62L⁺ naïve T cell culture, the PGI₂ analogs iloprost and cicaprost increased IL-17A and IL-22 protein production and Th17 differentiation in vitro. This effect was augmented by IL-23 and was dependent on PGI₂ receptor IP signaling. In mouse bone marrow-derived CD11c⁺ dendritic cells (BMDCs), PGI₂ analogs increased the ratio of IL-23/IL-12, which is correlated with increased ability of BMDCs to stimulate naïve T cells for IL-17A production. Moreover, IP knockout mice had delayed onset of a Th17-associated neurological disease, experimental autoimmune encephalomyelitis (EAE), and reduced infiltration of IL-17A-expressing mononuclear cells in the spinal cords compared to wild type mice. These results suggest that PGI₂ promotes in vivo Th17 responses.

Conclusion

The preferential stimulation of Th17 differentiation by IP signaling may have important clinical implications as PGI₂ and its analogs are commonly used to treat human pulmonary hypertension.

Modafinil inhibits K(Ca)3.1 currents and muscle contraction via a cAMP-dependent mechanism

Modafinil has been used as a psychostimulant for the treatment of narcolepsy. However, its primary mechanism of action remains elusive. Therefore, we examined the effects of modafinil on K(Ca)3.1 channels and vascular smooth muscle contraction. K(Ca)3.1 currents and channel activity were measured using a voltage-clamp technique and inside-out patches in mouse embryonic fibroblast cell line, NIH-3T3 fibroblasts. Intracellular adenosine 3',5'-cyclic monophosphate (cAMP) concentration was measured, and the phosphorylation of K(Ca)3.1 channel protein was examined using western blotting in NIH-3T3 fibroblasts and/or primary cultured mouse aortic smooth muscle cells (SMCs). Muscle contractions were recorded from mouse aorta and rat pulmonary artery by using a myograph developed in-house. Modafinil was found to inhibit K(Ca)3.1 currents in a concentration-dependent manner, and the half-maximal inhibition (IC(50)) of modafinil for the current inhibition was 6.8 ± 0.7 nM. The protein kinase A (PKA) activator forskolin also inhibited K(Ca)3.1 currents. The inhibitory effects of modafinil and forskolin on K(Ca)3.1 currents were blocked by the PKA inhibitors PKI(14-22) or H-89. In addition, modafinil relaxed blood vessels (mouse aorta and rat pulmonary artery) in a concentration-dependent manner. Modafinil increased cAMP concentrations in NIH-3T3 fibroblasts or primary cultured mouse aortic SMCs and phosphorylated K(Ca)3.1 channel protein in NIH-3T3 fibroblasts. However, open probability and single-channel current amplitudes of K(Ca)3.1 channels were not changed by modafinil. From these results, we conclude that modafinil inhibits K(Ca)3.1 channels and vascular smooth muscle contraction by cAMP-dependent phosphorylation, suggesting that modafinil can be used as a cAMP-dependent K(Ca)3.1 channel blocker and vasodilator.

Two non-vesicular ATP release pathways in the mouse erythrocyte membrane

Erythrocytes are exceptionally suited for analysis of non-exocytotic release mechanisms of ATP, because these cells under physiological conditions lack vesicles. Previous studies have indicated, that Pannexin1 (Panx1) provides a key ATP permeation pathway in many cell types, including human and frog erythrocytes. Here we show that erythrocytes of Panx1(-/-) mice lend further support to this conclusion. However, ATP release, although attenuated, was still observed in Panx1(-/-) mouse erythrocytes. In contrast to Panx1(+/+) cells, this release was not correlated with uptake of extracellularly applied dyes, was insensitive to Panx1 channel blockers, and was inhibited by dipyridamole and stimulated by iloprost. Thus, in erythrocytes, two independent pathways mediate the release of ATP. We also show that glyburide is a strong inhibitor of Panx1 channels.

Prostacyclin administration as a beneficial supplement to the conventional cancer chemotherapy

Prostacyclin (PGI(2)) and its analogues protect from cardiovascular disease through pleiotropic effects such as vasodilation, inhibition of platelet aggregation, leukocyte adhesion, and vascular smooth muscle cell (VSMC) proliferation. Additionally, prostacyclin synthase (PGIS) and PGI(2) also possess anti-cancer properties. As of late (2009-2010), numerous studies have identified the deleterious side-effects of chemotherapy on the cardiovascular system, which have been deemed as a serious clinical issue. Cardiomyocyte damage, induced by oxidative stress, is one of the clinical consequences caused by routine cancer chemotherapy. Previous studies indicate iloprost, a PGI(2) analogue, can protect against doxorubicin-induced (DOX) cardiomyocyte injury in vitro and in vivo without compromising tumor suppression. Therefore, we hypothesize PGI(2) can be used as a cardioprotective supplement to attenuate the damaging cardiac effects caused by the traditional cancer chemotherapy regimen.

[Immediately effects of inhaled aerosolised iloprost in adult patients with severe pulmonary hypertension secondary to congenital heart diseases]

OBJECTIVE

To investigate the immediately effects of inhaled aerosolized iloprost in adult patients with severe pulmonary arterial hypertension (PAH) secondary to congenital heart diseases (CHD).

METHODS

Adult patients with severe PAH secondary to CHD (n = 165) were included in this study. Right heart catheterization was performed, Pulmonary and systemic blood flow, the oxygen consumption VO(2) (ml/min) were calculated using Fick's principle. Pulmonary vascular resistances (PVR) were calculated with standard formulas and indexed to body surface area. Hemodynamic parameters were measured before and after iloprost inhalation (20 µg).

RESULTS

Post iloprost inhalation, heart rate, mean aortic pressure, pulmonary systolic pressure to aortic systolic pressure ratio all remained un changed (P > 0.05), while pulmonary artery pressure (PAP) were significantly reduced and Qp significantly increased from (7.2 ± 4.8) L/min to (9.9 ± 7.2) L/min (P < 0.01), PVR was also significantly reduced from (13.4 ± 8.7) Wood units to (9.5 ± 6.6) Wood units (P < 0.01), and left-to-right shunt volume increased from (3.2 ± 4.4) L/min to (5.5 ± 7.0) L/min (P < 0.01) and right-to-left shunt volume decreased from (1.0 ± 1.0) L/min to (0.7 ± 0.7) L/min (P < 0.01). Subgroup analysis showed that adult patients with patent ductus arteriosus and/or ventricular septal defects are more likely to develop severe pulmonary arterial hypertension or Eisenmenger syndrome than patients with atrial septal defects.

CONCLUSIONS

Inhaled Aerosolised iloprost use is effective and safe for adult patients with severe pulmonary arterial hypertension secondary to congenital heart diseases.

Prostaglandin I(2) analogues enhance growth-related oncogene-alpha expression in human monocyte-derived dendritic cells

Chemokines for neutrophils such as growth-related oncogene-alpha (GRO-alpha) are important in patients with refractory or severe asthma. Prostaglandin I(2) (PGI(2)) analogues were regarded as potential treatments for asthma. Dendritic cells (DCs) are the professional antigen-presenting cells and play a critical role in regulating immune response. However, it is unknown whether PGI(2) analogues have regulatory effects on GRO-alpha expression in human monocyte-derived DCs (MDDCs). The human MDDCs were pretreated with iloprost and treprostinil (two PGI(2) analogues) or forskolin, a cyclic adenosine monophosphate (cAMP) activator, before stimulation with lipopolysaccharide (LPS). In some cases, I prostanoid (IP) receptor and E prostanoid (EP) antagonists were pretreated before PGI(2) analogue treatment. To investigate the intracellular signaling, nuclear factor (NF)-kappaB inhibitor and the mitogen-activated protein kinase (MAPK) inhibitors were pretreated before PGI(2) analogue treatment. GRO-alpha was measured by enzyme-linked immunosorbent assay. Intracellular signaling was also investigated by Western blot. Iloprost and treprostinil enhanced LPS-induced GRO-alpha expression in MDDCs. This effect could be reversed by an I prostanoid receptor antagonist, CAY10449, but not EP receptor antagonists. Forskolin conferred a similar modulating effect as that noted in iloprost- and treprostinil-treated MDDCs. PGI(2) analogue-enhanced LPS-induced GRO-alpha expression was reduced by MAPK-p38 inhibitor, SB203580. PGI(2) analogues enhanced LPS-induced phospho-p38 expression. PGI(2) analogues enhanced LPS-induced GRO-alpha expression via the IP receptor-cAMP and p38-MAPK pathways in human MDDCs, which may further recruit neutrophil accumulation and adversely affect patients with refractory or severe asthma because of airway neutrophilia. These effects should be considered for PGI(2) analogues as candidates for the treatment of asthma.

Smooth muscle proliferation and role of the prostacyclin (IP) receptor in idiopathic pulmonary arterial hypertension

RATIONALE

Prostacyclin analogs, used to treat idiopathic pulmonary arterial hypertension (IPAH), are assumed to work through prostacyclin (IP) receptors linked to cyclic AMP (cAMP) generation, although the potential to signal through peroxisome proliferator-activated receptor-γ (PPARγ) exists.

OBJECTIVES

IP receptor and PPARγ expression may be depressed in IPAH. We wished to determine if pathways remain functional and if analogs continue to inhibit smooth muscle proliferation.

METHODS

We used Western blotting to determine IP receptor expression in peripheral pulmonary arterial smooth muscle cells (PASMCs) from normal and IPAH lungs and immunohistochemistry to evaluate IP receptor and PPARγ expression in distal arteries.

MEASUREMENTS AND MAIN RESULTS

Cell proliferation and cAMP assays assessed analog responses in human and mouse PASMCs and HEK-293 cells. Proliferative rates of IPAH cells were greater than normal human PASMCs. IP receptor protein levels were lower in PASMCs from patients with IPAH, but treprostinil reduced replication and treprostinil-induced cAMP elevation appeared normal. Responses to prostacyclin analogs were largely dependent on the IP receptor and cAMP in normal PASMCs, although in IP(-/-) receptor cells analogs inhibited growth in a cAMP-independent, PPARγ-dependent manner. In IPAH cells, antiproliferative responses to analogs were insensitive to IP receptor or adenylyl cyclase antagonists but were potentiated by a PPARγ agonist and inhibited (∼ 60%) by the PPARγ antagonist GW9662. This coincided with increased PPARγ expression in the medial layer of acinar arteries.

CONCLUSIONS

The antiproliferative effects of prostacyclin analogs are preserved in IPAH despite IP receptor down-regulation and abnormal coupling. PPARγ may represent a previously unrecognized pathway by which these agents inhibit smooth muscle proliferation.

[Inhaled iloprost during acute pulmonary vasodilator testing for preoperative assessment of surgical operability of congenital heart disease with severe pulmonary hypertension]

OBJECTIVE

To evaluate the efficacy of iloprost in acute vasodilatation test during cardiac catheterization and to explore a useful hemodynamic indication regarding operability in the patients with severe pulmonary hypertension (PH) related to congenital heart disease (CHD).

METHODS

The clinical data of 46 patients [mean age (12 ± 9) years] with severe PH related to CHD from June 2006 to December 2008 was retrospectively analyzed. All patients underwent standard right and left cardiac catheterization and a trial of inhaled iloprost test during cardiac catheterization. The mean pulmonary arterial pressure was (80 ± 13) mm Hg (1 mm Hg = 0.133 kPa) and pulmonary vascular resistance index was (17 ± 10) wood.m². A positive response to inhaled iloprost was defined as a decrease of at least 20% in pulmonary vascular resistance index (PVRI) without changes on systemic artery pressure. Patients with positive response to iloprost underwent cardiac surgical repair. The pulmonary artery pressure and PVRI was monitored by Swan-Ganz catheter postoperatively.

RESULTS

Of the 46 patients, 29 (63.1%) showed a positive response after iloprost inhalation, defined by a significant reduction in PVRI from (15 ± 6) wood.m(2) at baseline to (9 ± 4) wood.m² in response to iloprost inhalation therapy (P < 0.05). The ratio of pulmonary to systemic resistance (Rp/Rs) decreased from 0.7 ± 0.2 to 0.4 ± 0.2 (P < 0.05). Seventeen patients (36.9%) didn't respond to iloprost displayed only little changes in PVRI [from (21 ± 10) wood.m(2) to (19 ± 9) wood.m²] and Rp/Rs (from 1.0 ± 0.5 to 0.9 ± 0.5). Out of 29 positive patients, 21 (72%) underwent successful cardiac surgical repair with a reduction of mean pulmonary arterial pressure (mPAP) to an average of (27 ± 10) mm Hg after the operation. Only 2 patients out of the 17 patients from the negative group were referred to surgery. Their mPAP was greater than 45 mm Hg.

CONCLUSIONS

A significant reduction in pulmonary artery pressure after cardiac surgery was observed in patients with positive response to inhaled iloprost. Inhaled iloprost may be a valuable tool in the preoperative evaluation of patients with severe PH related to CHD.

In central obesity, weight loss restores platelet sensitivity to nitric oxide and prostacyclin

Central obesity shows impaired platelet responses to the antiaggregating effects of nitric oxide (NO), prostacyclin, and their effectors--guanosine 3',5'-cyclic monophosphate (cGMP) and adenosine 3',5'-cyclic monophosphate (cAMP). The influence of weight loss on these alterations is not known. To evaluate whether a diet-induced body-weight reduction restores platelet sensitivity to the physiological antiaggregating agents and reduces platelet activation in subjects affected by central obesity, we studied 20 centrally obese subjects before and after a 6-month diet intervention aiming at reducing body weight by 10%, by measuring (i) insulin sensitivity (homeostasis model assessment of insulin resistance (HOMA(IR))); (ii) plasma lipids; (iii) circulating markers of inflammation of adipose tissue and endothelial dysfunction, and of platelet activation (i.e., soluble CD-40 ligand (sCD-40L) and soluble P-selectin (sP-selectin)); (iv) ability of the NO donor sodium nitroprusside (SNP), the prostacyclin analog Iloprost and the cyclic nucleotide analogs 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP) and 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP) to reduce platelet aggregation in response to adenosine-5-diphosphate (ADP); and (v) ability of SNP and Iloprost to increase cGMP and cAMP. The 10 subjects who reached the body-weight target showed significant reductions of insulin resistance, adipose tissue, endothelial dysfunction, and platelet activation, and a significant increase of the ability of SNP, Iloprost, 8-Br-cGMP, and 8-Br-cAMP to reduce ADP-induced platelet aggregation and of the ability of SNP and Iloprost to increase cyclic nucleotide concentrations. No change was observed in the 10 subjects who did not reach the body-weight target. Changes of platelet function correlated with changes of HOMA(IR). Thus, in central obesity, diet-induced weight loss reduces platelet activation and restores the sensitivity to the physiological antiaggregating agents, with a correlation with improvements in insulin sensitivity.

The in vitro effects of iloprost with other vasodilators on the human internal thoracic artery

PURPOSE

We aimed (a) to analyze the effects of iloprost as a vasodilator on the human internal thoracic artery (ITA) and (b) to compare these effects with the effects of other vasodilators now being used in the clinic.

METHODS

Following transfer into only Krebs solution or into Krebs solution containing papaverine or iloprost, human ITA strips were then incubated only in Krebs or in Krebs with vasodilators that are generally used in clinical practice, such as diltiazem or glyceryl trinitrate. Cumulative concentration-contraction curves for noradrenaline (NA) and KCl were then established for these strips. Student's t-test and one-way analysis of variance followed by Tukey-Kramer tests were used to compare differences between groups. A p <0.05 was used to indicate significance.

RESULTS

Among the transfer solutions, papaverine (6.50 ± 0.20) and iloprost (7.33 ± 0.13) were significantly more potent than Krebs (8.46 ± 0.75, p <0.001 and p <0.05) with regard to preventive effect on precontracted ITA with NA. Iloprost significantly relaxed the NA-induced precontracted ITA strips in the Krebs, papaverine, and iloprost groups. Diltiazem significantly relaxed the precontracted ITA with KCl in all storage groups.

CONCLUSION

Iloprost may also prevent perioperative ITA spasm, but should be tested in the clinical setting.

[The acute effects of inhaled iloprost on hemodynamics and oxygenation in chronic thromboembolic pulmonary hypertension]

OBJECTIVE

To evaluate the acute effects of inhaled iloprost on hemodynamics and oxygenation in chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

A prospective study was made. Eighteen patients with CTEPH were enrolled. At right heart catheterisation, iloprost was inhaled at 20 microg for 10 - 15 min. Compare the value of heart rate (HR), mean blood pressure (mBP), mean pulmonary arterial hypertension (mPAP), right atrium pressure (RAP), pulmonary arterial wedge pressure (PAWP), cardiac output (CO), pulmonary vascular resistance (PVR), systemic vascular resistance (SVR), arterial partial pressure of oxygen (PaO2), arterial oxygen saturation (SaO2), mixed venous saturation (SvO2), pulmonary shunt fraction (Qs/Qt), alveolar-arterial partial pressure of oxygen [P ( A-a) O2] before to after inhaled iloprost in these patients.

RESULTS

Significant changes (before to after inhalation): mPAP, (53 +/- 11) to (47 +/- 14) mm Hg (P < 0.01); PVR, (821 +/- 194) to (681 +/- 199) dyn x s x cm(-5) (P < 0.01); RAP, (10 +/- 6) to (7 +/- 6) mm Hg (P < 0.01). However, HR, PAWP, mBP, CO and SVR had no significant changes. At the same time, inhaled iloprost significantly decreased PaO2 from (58 +/- 11) to (52 +/- 6) mm Hg (P < 0.01) and increased Qs/Qt from (27 +/- 11)% to (33 +/- 9)% (P < 0.01)and P(A-a) O2 from (86 +/-39) to (93 +/- 38) mm Hg (P < 0.01).

CONCLUSION

Inhaled iloprost might instantly improve hemodynamics in CTEPH, but at the same time it increased arteriovenous shunts which resulted in lower PaO2.

[The oxygen kinetic effect of inhaled iloprost in pulmonary artery hypertension and chronic thromboembolic pulmonary hypertension]

OBJECTIVE

To study the acute oxygen kinetic effect of inhaled iloprost in pulmonary artery hypertension and chronic thromboembolic pulmonary hypertension.

METHODS

Twenty-two and 24 patients who were admitted to our hospital between June 2006 and January 2009 with confirmed diagnosis of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) respectively were enrolled to this study. During right heart catheterization, the hemodynamics and oxygen kinetics were monitored at baseline and after inhaling Iloprost (20 micrograms).

RESULTS

At baseline, the arterial partial pressure of oxygen (PaO2) was (63 +/- 10) mm Hg (1 mm Hg = 0.133 kPa) and (59 +/- 10) mm Hg respectively in PAH and CTEPH patients, and the oxygen delivery index (DO2I) and oxygen consumption index (VO2I) were (458 +/- 136) ml x min(-1) x m(-2) and (135 +/- 53) ml x min(-1) x m(-2) in PAH patients respectively, and (386 +/- 92) ml x min(-1) x m(-2) and (131 +/- 43) ml x min(-1) x m(-2) in CTEPH patients respectively. Three minutes after inhaling Iloprost, for PAH and CTEPH patients, the pulmonary shunt rate (Qs/Qt) all increased significantly (all P < 0.05, respectively) as well as the difference of oxygen partial pressure between pulmonary alveoli and artery (P[A-a]O2, all P < 0.05, respectively), and the arterial oxygen content (CaO2) all decreased significantly (all P < 0.05, respectively). The oxygenation parameters of mixed venous blood, oxygen extractive rate and DO2I did not change significantly, but VO2I declined to different extent. The extent of change after inhaling Iloprost for all oxygen kinetic parameters were similar between PAH and CTEPH patients. At baseline, mixed venous oxygen saturation (SvO2), venous oxygen content (CvO2) and DO2I in CTEPH patients were lower than those in PAH patients. After inhaling Iloprost, in CTEPH patients, PaO2, SvO2 and CvO2 were lower than those in PAH patients.

CONCLUSION

There were hypoxemia and abnormality of oxygen kinetics in PAH and CTEPH patients. After inhaling Iloprost, pulmonary shunt increased without improvement in oxygen kinetics. Oxygenation should be monitored closely and supply oxygen supplied for CTEPH when inhaling Iloprost.

Prostacyclin analogue iloprost influences endothelial cell-associated soluble adhesion molecules and growth factors in patients with systemic sclerosis: a time course study of serum concentrations

Systemic sclerosis is a connective tissue disorder with unclear aetiology and pathogenesis. However, there is evidence that microvascular changes belong to the early symptoms of the disease. These are associated with increased serum levels of markers of endothelium activation, such as adhesion molecules and growth factors. The stable prostacyclin analogue iloprost is licensed for vascular symptoms (Raynaud's phenomenon) and was recently shown to exert short-term effects on these markers. In this study, serum samples (n = 13) from patients with systemic sclerosis were examined for serum levels of vascular cell adhesion molecule-1 (VCAM-1), intercellular cell adhesion molecule-1, E-selectin, endothelin-1 and vascular endothelial growth factor over 6 months after iloprost infusions in order to detect possible long-term effects. Iloprost significantly reduced initially elevated levels of these markers, partly until the end of the observation period (E-selectin, VCAM-1, endothelin-1). These effects provide serological evidence for the benefits of iloprost infusions that are seen clinically in patients with systemic sclerosis.

Donor heart preservation with iloprost supplemented St. Thomas Hospital cardioplegic solution in isolated rat hearts

This study was designed to assess the influence of St. Thomas Hospital cardioplegic solution (St. Th.) on heart preservation in rat hearts subjected to 6h ischemia when supplemented with iloprost. In the control group (n=8), nothing was added to St. Th., whereas 10 or 1000 nmol L(-1) iloprost was added in the second (n=7) and third (n=8) groups, respectively. Mechanical contraction parameters, cardiac tissue damage and oxidative stress markers were evaluated. The 10 nmol/L iloprost group peak systolic pressure (71.0+/-30.9 versus 41.0+/-9.4 mm Hg) and -dp/dtmax (1103.8+/-94.3 versus 678.6+/-156.8 mm Hg s(-1)) were significantly higher than control group at 30 min of reperfusion (p<0.05). Iloprost supplemented groups had higher GSH and catalase levels of coronary perfusate at reperfusion, in comparison with initial values (p<0.05). AST, CK, CK-MB values increased at 0 min of reperfusion and cTnI values at 45 min of reperfusion (p<0.05) in all groups with no difference between groups. According to our results, iloprost supplementation had mild but significant improvement in postischemic values in mechanical and oxidative stress parameters, resulting in better heart preservation.