Aerosol drug delivery: developments in device design and clinical use

Aerosolised drugs are prescribed for use in a range of inhaler devices and systems. Delivering drugs by inhalation requires a formulation that can be successfully aerosolised and a delivery system that produces a useful aerosol of the drug; the particles or droplets need to be of sufficient size and mass to be carried to the distal lung or deposited on proximal airways to give rise to a therapeutic effect. Patients and caregivers must use and maintain these aerosol drug delivery devices correctly. In recent years, several technical innovations have led to aerosol drug delivery devices with efficient drug delivery and with novel features that take into account factors such as dose tracking, portability, materials of manufacture, breath actuation, the interface with the patient, combination therapies, and systemic delivery. These changes have improved performance in all four categories of devices: metered dose inhalers, spacers and holding chambers, dry powder inhalers, and nebulisers. Additionally, several therapies usually given by injection are now prescribed as aerosols for use in a range of drug delivery devices. In this Review, we discuss recent developments in the design and clinical use of aerosol devices over the past 10-15 years with an emphasis on the treatment of respiratory disorders.

Discontinuing long-term Iloprost treatment for Raynaud's Phenomenon and systemic sclerosis: a single-center, randomized, placebo-controlled, double-blind study

BACKGROUND

Iloprost has been reported to reduce Raynaud`s phenomenon (RP) and to inhibit progression of systemic sclerosis (SSc).

OBJECTIVE

The aim of our study was to compare monthly iloprost infusions with placebo in patients treated long-term.

METHODS

Seventeen patients, six with RP and 11 with SSc on monthly treatment with iloprost, received either a 3-hour intravenous infusion of iloprost or an equal volume of placebo once per month for 4 months in a monocentric, randomized, placebo-controlled, double-blind study. Raynaud attacks as measured by diary entries, skin temperature, skin sclerosis, fist closure, mouth opening, and digital ulcers were recorded during the observation period.

RESULTS

Whereas mouth opening improved significantly (p = 0.043) in the iloprost-treated group, RS improved in both patient groups. However, no significant differences were found in the outcome measures.

CONCLUSION

Although iloprost influences the inflammatory cascade in SSc, no statistical differences were seen in our study, indicating that treatment strategies with iloprost should be modified.

[Safety and tolerability of local treatment with Iloprost in patients with Peyronie's disease. A phase 1 pilot study and proposal of a new symptom questionnaire]

PURPOSE

Intralesional therapy is a less invasive method for the treatment of Peyronie's disease. The objective of this study was to evaluate safety and tolerability of intralesional injections of Iloprost (I2 Prostacyclin analogue) for its property to suppress in fibroblasts CTFG (Connective tissue growth factor) production, which acts in concert with TGF-ß to stimulate the fibrotic process.

METHODS

Nineteen patients with Peyronie's disease were preliminarily evaluated by considering the degree of penile curvature, plaque size and local and systemic symptoms. Each patient then received weekly intralesional injections of 200 ng of Iloprost in 1 ml of normal saline for 4-5 weeks. If tolerated, the single dose increased weekly to the maximum of 400 ng (2 mL).

RESULTS

The treatment has shown that all patients seem to well tolerate a 200 ng Iloprost dose; 7 of them reached a 300 ng dose and 6 tolerate a 400 ng dose without showing side effects. There was no placebo control group in this study. To evaluate the efficacy of the treatment, the absence of objective parameters (except for the auto-photograph of penis in erection) led us to develop a subjective questionnaire that was given to all patients to assess sexual function, pain reduction, ecc.

CONCLUSIONS

Due to the relatively small size of the sample, the efficacy evaluation has been restricted to check the questionnaire reliability. Iloprost is well tolerated to a dose of 400 ng in the local treatment of Peyronie's disease.

Combined vasomodulatory therapy for severe pulmonary hypertension in chronic hypersensitivity pneumonitis

BACKGROUND

There are only a few reports of pulmonary hypertension (PH) in hypersensitivity pneumonitis (HP) and an approved vasomodulatory therapy for PH does not exist at all for interstitial lung disease (ILD), particularly for HP.

CASE REPORT

The case of a 53-year-old woman with chronic HP and severe life-threatening PH treated with a combined specific vasomodulatory therapy is reported. Sustained clinical and hemodynamic improvement was achieved.

CONCLUSIONS

Further investigation of PH in HP and specific vasomodulatory therapy is necessary.

Iloprost inhalation redistributes pulmonary perfusion and decreases arterial oxygenation in healthy volunteers

BACKGROUND

Previous studies have shown that ventilation-perfusion matching is improved in the prone as compared with that in the supine position. Regional differences in the regulation of vascular tone may explain this. We have recently demonstrated higher production of nitric oxide in dorsal compared with ventral human lung tissue. The purpose of the present study was to investigate regional differences in actions by another vasoactive mediator, namely prostacyclin. The effects on gas exchange and regional pulmonary perfusion in different body positions were investigated at increased prostacyclin levels by inhalation of a synthetic prostacyclin analogue and decreased prostacyclin levels by unselective cyclooxygenase (COX) inhibition.

METHODS

In 19 volunteers, regional pulmonary perfusion in the prone and supine position was assessed by single photon emission computed tomography using (99m)Tc macro-aggregated albumin before and after inhalation of iloprost, a stable prostacyclin analogue, or an intravenous infusion of a non-selective COX inhibitor, diclofenac. In addition, gas distribution was assessed in seven subjects using (99m)Tc-labelled ultra-fine carbon particles before and after iloprost inhalation in the supine position.

RESULTS

Iloprost inhalation decreased arterial PaO(2) in both prone (from 14.2+/-0.5 to 11.7+/-1.7 kPa, P<0.01) and supine (from 13.7+/-1.4 to 10.9+/-2.1 kPa, P<0.01) positions. Iloprost inhalation redistributed lung perfusion from non-dependent to dependent lung regions in both prone and supine positions, while ventilation in the supine position was distributed in the opposite direction. No significant effects of non-selective COX inhibition were found in this study.

CONCLUSIONS

Iloprost inhalation decreases arterial oxygenation and results in a more gravity-dependent pulmonary perfusion in both supine and prone positions in healthy humans.

Inhaled iloprost for sarcoidosis associated pulmonary hypertension

RATIONALE

Patients with sarcoidosis associated pulmonary hypertension (SAPH) have responded to systemic prostacyclin therapy.

OBJECTIVES

To determine the rate of response to inhaled prostacyclin, iloprost, in SAPH.

METHODS

Sarcoidosis patients with pulmonary hypertension and no evidence for left ventricular dysfunction were enrolled in an open label, prospective study. Patients underwent right heart catheterization and six minute walk (6MW) test. Quality of life was evaluated using several instruments, including the Saint George Respiratory Questionnaire (SGRQ). Patients received 5 mcg of inhaled iloprost every 2-3 hours while awake. After four months of therapy, patients underwent repeat cardiac catheterization, 6 MW test, and completed quality of life questionnaires.

MEASUREMENTS AND MAIN RESULTS

Of the 22 patients enrolled, 15 completed all 16 weeks of therapy. The most common reasons for study discontinuation included drug associated cough (3 patients) and compliance with the prescribed number of treatments per day (2 patients). Six patients experienced a 20% or greater decrease in pulmonary vascular resistance (PVR) from baseline with five of these six patients also showing > or = 5 mm Hg reduction in PA mean. Although three patients improved the 6MW distance by at least 30 meters, only one had a decrease in PVR. At 16 weeks a significant decrease was reported in the SGRQ activity score (p = 0.0273), with seven patients having a 4 point or greater decrease.

CONCLUSION

Inhaled iloprost as monotherapy was associated with an improvement in pulmonary hemodynamics and quality of life as assessed by the SGRQ activity score in some sarcoidosis patients with SAPH.

Bone marrow edema syndrome in postpartal women: treatment with iloprost

Bone marrow edema syndrome of the femoral head in pregnant women is a rare disease resulting in disabling coxalgia, beginning in the last 3 months of pregnancy and persisting for several months after parturition. The parenteral administration of the vasoactive drug iloprost constitutes a new approach to the treatment of painful bone marrow edema syndrome of the hip of pregnant women. Six postpartal women (8 hips) with bone marrow edema syndrome of the femoral head were treated with iloprost followed by 3 weeks of partial weight-bearing. Relief from pain, restoration of functional capacity, and normalization of the MRI signal pattern were rapidly achieved, thus avoiding the need for surgical intervention. As the substance is contraindicated in pregnancy, therapy may begin only some days after parturition, with a short discontinuation in breastfeeding.

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.

Iloprost therapy acutely decreases oxidative stress in patients affected by systemic sclerosis

BACKGROUND

Oxidative stress has been considered a leading factor in the pathogenesis of systemic sclerosis (SSc). Consistently with this hypothesis the determination of urinary isoprostanes, a reliable method for evaluation of oxidative stress, has recently showed increased levels of isoprostanes in SSc patients. Data about the effect on oxidative stress of accepted therapies for SSc such as iloprost therapy are lacking.

OBJECTIVE

The aim of this prospective study was to verify whether iloprost therapy in patients with SSc acutely reduces oxidative stress assessed by determination of 8-Iso PGF<inf>2alpha</inf> urinary levels.

METHODS

urine samples were obtained before and after a five-day cycle of iloprost infusion and urinary 8-Iso PGF<inf>2alpha</inf> levels were determined using a commercially available enzyme immunoassay.

RESULTS

Consistent with previous reports, we found an increased level of oxidative stress in SSc patients with respect to healthy controls. Basal urinary 8-iso PGF<inf>2alpha</inf> levels in SSc patients were significantly higher than those in healthy controls [2002(1122-3575) pg/mg creatinine vs. 334(225.7-441) pg/mg creatinine, p<0.001]. Moreover, as expected, urinary 8-iso PGF<inf>2alpha</inf> levels after iloprost therapy were significantly lower than basal levels [1277.5 pg/mg creatinine (742.7-2017.3) vs. 2002 pg/mg creatinine (1122-3575), p=0.001] but persisted significantly elevated respect to the levels of healthy controls (p<0.001). The effect of iloprost on oxidative stress appeared significant in patients with early and limited form of disease.

CONCLUSIONS

This prospective open-label explorative study suggests that standard course of iloprost therapy may acutely reduce oxidative stress in SSc patients. This effect appears to be more consistent in the early phases and in the limited subset of disease. Further larger trials are needed to confirm our results and to explain the pathway of such reduction, its clinical significance and potential therapeutic implications.

The prostacyclin analogue iloprost increases circulating endothelial progenitor cells in patients with critical limb ischemia

Patients with critical limb ischemia (CLI) have low levels of endothelial progenitor cells (EPC). Iloprost has been demonstrated to stimulate vascular endothelial growth factor (VEGF) and promote angiogenesis. We investigated the effects of iloprost on EPC levels in vivo in CLI patients. Twenty-three patients with stage III and IV CLI were treated with iloprost for four weeks, improving clinical and instrumental parameters. Mononuclear cells isolated from peripheral blood were cultured to obtain "early" EPC, evaluated counting adherent cells with double positivity for acetylated low-density lipoprotein uptake and Ulex Europaeus lectin at flow cytometry. These cells also co-expressed the monocyte markers CD14 and CD45. Iloprost increased EPC number in the whole patient population: pre-treatment median: 13,812/ml; range: 1,263-83,648/ml; post-treatment median: 23,739/ml; range: 3,385-99,251/ml; p = 0.035, irrespective of age, sex, disease stage or atherosclerosis risk factors. In conclusion, iloprost increases EPC number in peripheral blood in vivo. Such an effect may have therapeutic relevance.

Low versus high-dose iloprost therapy over 21 days in patients with secondary Raynaud's phenomenon and systemic sclerosis: a randomized, open, single-center study

OBJECTIVE

We compared the efficacy of different dosages of longterm iloprost treatment on Raynaud's phenomenon (RP), ulcer healing, skin thickening, and progression of internal organ sclerosis in patients with systemic sclerosis (SSc).

METHODS

Fifty patients with SSc were randomized 1:1 for the maximally tolerated dose up to 2 ng/kg body weight per minute or low-dose (0.5 ng/kg bw per min) intravenous iloprost administration, applied for 6 hours daily over 21 days. Effects on RP, ulcer healing, skin thickness, esophageal function, and lung involvement assessed by forced vital capacity (FVC) and DLCO were measured, as well as side effects.

RESULTS

Both regimens yielded 70% reduction of digital ulcers, 40% reduction in frequency of RP, and 30% reduction in duration of RP. One year after therapy, the modified Rodnan skin score appeared to be unchanged. FVC and DLCO-SB were stable in 87% and 74% of the patients, respectively. The effect of iloprost on skin thickness and lung function was sustained in a subgroup of patients receiving several courses of iloprost. As assessed by a patient questionnaire, 12% of all patients did not respond to iloprost therapy, but 78% experienced a longlasting effect. Mild side effects were common in both groups, but did not lead to discontinuation of therapy.

CONCLUSION

Low-dose iloprost was shown to be equally effective as high-dose iloprost in longterm treatment and was very effective in therapy of digital ulcers. Registered in www.ClinicalTrials.gov (registration no. NCT00622687).

Aerosolized Iloprost in the Treatment of Pulmonary Hypertension in Extremely Preterm Infants: A Pilot Study

BACKGROUND

In premature infants with preterm prolonged rupture of membranes, death after birth is often due to persistent pulmonary hyper-tension.

PATIENTS

Aerosolized iloprost was used to treat pulmonary hypertension due to prolonged preterm rupture of fetal membranes (7-56 days) in four extremely low-birthweight neonates (23-25 weeks' gestation, weight 448-645 g) under spontaneous breathing supported by nasal continuous positive airway pressure.

METHOD

Inhalation dose was 2 microg/kg b.w. and between 44 and 65 inhalations were performed in each patient starting within the first hour of life over a total of several days. Single inhalations lasted 5 min and were not repeated until 60 min had elapsed.

RESULTS

After the first inhalation, the PaO2/FiO2 mean ratio increased from 65 (range 35-114) to 194 (148-250) mmHg and oxygenation requirements decreased within the next 7 days. Echocardiography similarly showed reduction in pulmonary resistance. We observed no severe side effects on blood pressure or prolonged bleeding time during inhalation.

CONCLUSIONS

Iloprost inhalation might therefore be an additional treatment for improving oxygenation in cases of persistent pulmonary hypertension in extremely low-birthweight infants under spontaneous breathing. Further randomized clinical studies are required to establish the role of iloprost in this setting.

Inhaled iloprost to control pulmonary artery hypertension in patients undergoing mitral valve surgery: a prospective, randomized-controlled trial

BACKGROUND

Pulmonary hypertension (PHT) is common in patients undergoing mitral valve surgery and is an independent risk factor for the development of acute right ventricular (RV) failure. Inhaled iloprost was shown to improve RV function and decrease RV afterload in patients with primary PHT. However, no randomized-controlled trials on the intraoperative use of iloprost in cardiac surgical patients are available. We therefore compared the effects of inhaled iloprost vs. intravenous standard therapy in cardiac surgical patients with chronic PHT.

METHODS

Twenty patients with chronic PHT undergoing mitral valve repair were randomized to receive inhaled iloprost (25 microg) or intravenous nitroglycerine. Iloprost was administered during weaning from cardiopulmonary bypass (CPB). Systemic and pulmonary haemodynamics were assessed with pulmonary artery catheterization and transoesophageal echocardiography. Milrinone and/or inhaled nitric oxide were available as rescue medication in case of failure to wean from CPB.

RESULTS

Inhaled iloprost selectively decreased the pulmonary vascular resistance index after weaning from CPB (208 +/- 108 vs. 422 +/- 62 dyn.s/cm(5)/m(2), P<0.05), increased the RV-ejection fraction (29 +/- 3% vs. 22 +/- 5%, P<0.05), improved the stroke volume index (27 +/- 7 vs. 18 +/- 6 ml/m(2), P<0.05) and reduced the transpulmonary gradient (10 +/- 4 vs. 16 +/- 3 mmHg, P<0.05). In all patients receiving inhaled iloprost, weaning from CPB was successful during the first attempt. In contrast, three patients in the control group required re-institution of CPB and had to be weaned from CPB using rescue medication.

CONCLUSIONS

In patients with pre-existing PHT undergoing mitral valve surgery, inhaled iloprost is superior to intravenous nitrogylycerine by acting as a selective pulmonary vasodilator, reducing RV afterload and moderately improving RV-pump performance.

Aerosolized iloprost customized for the critically ill

BACKGROUND

Aerosolized iloprost, an inhaled synthetic analogue of prostacyclin, is an approved therapy for stage III and IV pulmonary hypertension. However, currently iloprost is delivered via a device that requires a clinically stable patient who can use a hand-held nebulizer. We designed separate aerosol delivery systems to nebulize iloprost to critically ill patients during (1) mechanical ventilation and (2) spontaneous breathing that requires a high fraction of inspired oxygen. The goal was to deliver doses similar to the currently approved high-efficiency I-neb nebulizer system.

METHODS

For the intubated patient we used the high-efficiency AeroTech II jet nebulizer and a breath-actuated ventilator circuit, without humidification. For spontaneous breathing, our delivery system consisted of a Pulmanex Hi-Ox disposable oxygen mask and an AeroTech II nebulizer. With a nebulizer charge of 20 microg, the drug presented to the patient (inhaled mass) was captured on a filter and analyzed using radioactivity (technetium-99m). The accuracy of the radiolabel was quantified by directly measuring iloprost with high-performance liquid chromatography and comparing the results. A cascade impactor measured particle distribution.

RESULTS

A line of identity confirmed that the radiolabel accurately represented the drug. The mean +/- SD inhaled mass was 6.02 +/- 0.87 microg (n = 5) on the ventilator and 3.77 +/- 0.46 microg (n = 5) during spontaneous ventilation. The mass median aerodynamic diameter and fine-particle fraction were 0.7 microm, 0.99, and 0.7 microm, 0.99, respectively.

CONCLUSIONS

Clinically effective doses of iloprost can be delivered to patients who require high-flow oxygen or mechanical ventilation.

Addressing a vascular endothelium array with blood components using underlying microfluidic channels

Here, we show that an array of endothelial cells, addressable by an underlying microfluidic network of channels containing red blood cells, can be employed as an in vitro model of in vivo circulation to monitor cellular communication between different cell types in the drug discovery process.

Hypoxia-induced pulmonary hypertension: Different impact of iloprost, sildenafil, and nitric oxide

OBJECTIVES

Chronic alveolar hypoxia induces pulmonary hypertension, evident from elevated pulmonary artery pressure (PAP), pulmonary vascular resistance, right ventricular hypertrophy (RVH), and increased muscularization of the pulmonary vasculature. Additionally, the vasoconstrictor response to acute hypoxia (HPV) may be reduced in the remodeled vasculature. However, no direct comparison of different treatments on the various parameters characterizing pulmonary hypertension has been performed yet. Against this background, we compared the effects of inhaled NO, infused iloprost, a stable prostacyclin analogue, and oral sildenafil, a phosphodiesterase 5 inhibitor, on hypoxia-induced pulmonary hypertension.

METHODS

Exposure of rabbits to chronic hypoxia (FiO(2)=0.10) for 42 days. Treatment with infused iloprost, oral sildenafil, and inhaled nitric oxide.

RESULTS

We quantified PAP, pulmonary vascular resistance, RVH, vascular remodeling, vasoreactivity, and the strength of HPV. Chronic hypoxia resulted in an increase in (a) the right ventricle/(left ventricle+septum) ratio from 0.26+/-0.01 to 0.44+/-0.01, (b) PAP, and (c) the degree of muscularization from 14.0+/-4.0% to 43.5+/-5.3%. Treatment with iloprost and sildenafil, but not with NO, prevented the increase in muscularization. In contrast, RVH was strongly inhibited by sildenafil, whereas NO had some minor, and iloprost had no effect. Only iloprost reduced PAP compared to NO and sildenafil. The downregulation of HPV was abrogated only by NO.

CONCLUSION

We demonstrated (a) that the parameters characterizing hypoxia-induced pulmonary hypertension are not functionally linked, (b) that the downregulation of HPV under chronic hypoxia can be prevented by inhaled NO but not by sildenafil and iloprost, and (c) that iloprost is particularly effective in preventing vascular remodeling and sildenafil in preventing RVH.

Preischemic iloprost application for improvement of graft preservation: which route is superior in experimental pig lung transplantation: inhaled or intravenous?

BACKGROUND

Optimal allograft protection is essential in lung transplantation to reduce postoperative organ dysfunction. Although intravenous prostanoids are routinely used to ameliorate reperfusion injury, the latest evidence suggests a similar efficacy of inhaled prostacyclin. Therefore, we compared donor lung-pretreatment using inhaled lioprost (Ventavis) with the commonly used intravenous technique.

METHODS

Five pig lungs were each preserved with Perfadex and stored for 27 hours without (group 1) or with (group-2, 100 prior aerosolized of iloprost were (group 3) or iloprost (IV). Following left lung transplantation, hemodynamics, Po(2)/F(i)o(2), compliance, and wet-to-dry ratio were monitored for 6 hours and compared to sham controls using ANOVA analysis with repeated measures.

RESULTS

The mortality was 100% in group 3. All other animals survived (P < .001). Dynamic compliance and PVR were superior in the endobronchially pretreated iloprost group as compared with untreated organs (P < .05), whereas oxygenation was comparable overall W/D-ratio revealed significantly lower lung water in group 2 (P = .027) compared with group 3.

CONCLUSION

Preischemic alveolar deposition of iloprost is superior to IV pretreatment as reflected by significantly improved allograft function. This strategy offers technique to optimize pulmonary preservation.

Sustained success of therapy with inhaled iloprost for severe pulmonary arterial hypertension associated with systemic sclerosis and pulmonary fibrosis

CASE REPORT

We report here the case of a woman with diffuse cutaneous systemic sclerosis with pulmonary involvement and severe (WHO functional class III) pulmonary arterial hypertension (PAH) and recurrent cardiac decompensation. The simultaneous presence of primary biliary cirrhosis with markedly elevated transaminase levels constituted a contraindication for bosentan, which would otherwise have been the first-line treatment for PAH. The patient was therefore treated with inhaled iloprost.

DISCUSSION

Once inhaled iloprost therapy had been started, we promptly noted a definite and sustained improvement in physical exercise capacity and normalisation of haemodynamic variables. In cases where bosentan is contraindicated, inhaled iloprost is an effective alternative for the treatment of severe PAH.

Iloprost infusion does not reduce oxidative stress in systemic sclerosis

Systemic sclerosis is a connective tissue disease in which oxidative stress represents an important player among the complex pathogenetic mechanisms of the disease. Iloprost, an analogue of natural prostacyclin, is used in systemic sclerosis for the treatment of severe Raynaud's phenomenon and ischemic ulcers. There is a clear evidence that iloprost attenuates oxidative damage induced by ischemia-reperfusion phenomena. The aim of this study is to evaluate the effect of iloprost on oxidative status in ten patients with systemic sclerosis by measuring urinary levels of 8-isoprostaglandin-F(2alpha), a member of F(2)-isoprostanes. We found that systemic sclerosis patients cyclically treated with iloprost showed increased urinary level of 8-isoprostaglandin-F(2alpha )in comparison with healthy subjects; urinary 8-isoprostaglandin-F(2alpha) did not diminish soon after the iloprost infusion as well as 3, 15 and 30 days after the drug administration. Unlike experimental studies, in vivo the strong vasodilator effect of iloprost infusion did not reduce oxidative status.

[Livedo racemosa with ulcerations. Cyclic therapy with iloprost infusions]

A 43 year old woman suffered from an intermittent painful livedo racemosa at the back since her childhood. Her clinical course was complicated by ulcerations. In careful clinical investigations no signs of an underlying disease could be found, in particular a Sneddon syndrome could be excluded. By means of both conservative and surgical treatments, initial healing of the ulcerations was achieved but relapses occurred. Cyclic infusions of iloprost achieved long-term clearing of the ulcerations and disappearance of the pain. To the best of our knowledge the effectiveness of this treatment has not been described for this disease in the literature.

An alternative agent for radial arterial graft spasm: application of topical iloprost

OBJECTIVE

This study is planned bringing about a new choice for the prophylaxis of RA spasm which is topical iloprost and compares its efficacy with papaverine and diltiazem.

DESIGN

Twenty eight CABG patients with RA grafts were categorized into four groups by taking into account the topical vasodilator (papaverine, diltiazem, iloprost and saline) that was utilized during harvesting. Arterial segments were separated into four rings and were than soaked with KCL, norepinephrine, phenylephrine and serotonin. Then, acetylcholine was given to induce relaxation and the preparations were put to rest for 10 minute.

RESULTS

The contraction response achieved by the vasoreactive agents was most effectively inhibited by papaverine. The effectiveness of the response obtained by iloprost was similar to that of papaverine and significantly stronger than that of diltiazem. Especially at high vasoreactive substance concentrations, diltiazem had a contraction close to that of the control while the protective effect was weaker than those of papaverine and iloprost.

CONCLUSION

Iloprost can be recommended as a strong alternative to the topical agents used for preventing arterial graft spasm.

Influence of the stable prostacyclin analog iloprost on the healing of colonic anastomosis in rats

AIM

The aim of this study was to investigate whether iloprost injected intraperitoneally immediately after colon resection can improve anastomotic healing on the fifth and eighth postoperative days.

METHODS

Forty Wistar rats were randomised into 2 equal groups. After the resection of a 1 cm segment of transverse colon, an end to end sutured anastomosis was generated. From the day of the operation, group 1 (control) received intraperitoneal 3 cc saline solution once daily until sacrifice, while group 2 (iloprost) received iloprost in a dose of 2 mg/kg body weight intraperitoneally once daily until sacrifice. Each group was further randomly divided into 2 equal subgroups and animals were sacrificed on the fifth (subgroup A), and eighth (subgroup B) postoperative days. After sacrifice, anastomoses were examined macroscopically and were measured for bursting pressures and tissue hydroxyproline levels while anastomotic healing process was evaluated histopathologically.

RESULTS

None of the rats exhibited any clinical evidence of leakage and there were no instances of peri-anastomotic abscess or peritonitis. Bursting pressure on the fifth postoperative day was significantly higher in the iloprost group than in the control group (P<0.001), while on the eighth postoperative day, bursting pressure was higher in the iloprost group but not significantly different (P=0.165). On both the fifth and eighth postoperative days rats in the iloprost group developed significantly more marked neo-angiogenesis and, in parallel with this, there was a trend showing a higher inflammatory cell infiltration.

CONCLUSION

The intraperitoneal administration of iloprost promoted neo-angiogenesis and enhanced colonic healing on the fifth postoperative day.