Time course of the protective effect of inhaled heparin on exercise-induced asthma

Efficacy and safety of inhaled heparin in asthmatic and chronic obstructive pulmonary disease patients: a systematic review and a meta-analysis

Asthma and chronic obstructive pulmonary disease (COPD) are prevalent chronic respiratory disorders that cause significant morbidity and mortality. Some studies evaluated the use of inhaled unfractionated heparin (UFH) in the treatment of asthma and COPD. We aimed to synthesize the available evidence for the efficacy and safety of inhaled heparin in improving lung functions among asthmatic and COPD patients. A comprehensive search was performed using Pubmed, Embase, EBSCO, Scopus, Web of Science, Cochrane CENTRAL, WHO Clinical trials, clinicaltrials.gov, Iranian Clinical trials, Google Scholar, Research Gate, ProQuest Thesis, OVID, and medRxiv databases. Two independent reviewers included all pertinent articles according to PRISMA guidelines, and extract data independently. The two reviewers checked the quality of studies using the ROB2 tool. To determine the pooled effect estimate of the efficacy and safety of inhaled heparin, a meta-analysis was carried out using the R programming language. Publication bias was evaluated using Egger's regression test. The heterogeneity was explained using a meta-regression, and the quality of evidence was assessed by the GRADE approach. Twenty-six studies with a total of 581 patients were included in the qualitative analysis and 16 in the meta-analysis. The primary outcome was treatment success (improvement of lung function) that was measured by standardized mean differences (SMD) of the forced expiratory volume per second (FEV1) either per ml or percentage. Heparin has a large effect on both FEV1% and FEV1 ml when compared to the control group (SMD 2.7, 95% CI 1.00; 4.39; GRADE high, SMD 2.12, 95% CI - 1.49; 5.72: GRADE moderate, respectively). Secondary outcomes are other lung functions improving parameters such as PC20 (SMD 0.91, 95% CI - 0.15; 1.96). Meta-regression and subgroup analysis show that heparin type, dose, year of publication, study design, and quality of studies had a substantial effect. Regarding safety, inhaled heparin showed a good coagulation profile and mild tolerable side effects. Inhaled heparin showed improvement in lung functions either alone or when added to standard care. More large parallel RCTs are needed including COPD patients, children, and other types, and stages of asthmatic patients.

Chondroitin sulfate inhibits secretion of TNF and CXCL8 from human mast cells stimulated by IL-33

Glycosaminoglycans (GAGs) are linear, highly negatively charged carbohydrate chains present in connective tissues. Chondroitin sulfate (CS) and heparin (Hep) are also found in the numerous secretory granules of mast cells (MC), tissue immune cells involved in allergic and inflammatory reactions. CS and Hep may inhibit secretion of histamine from rat connective tissue MC, but their effect on human MC remains unknown. Human LAD2 MC were pre-incubated with CS, Hep, or dermatan sulfate (DS) before being stimulated by either the peptide substance P (SP, 2 μM) or the cytokine IL-33 (10 ng/mL). Preincubation with CS had no effect on MC degranulation stimulated by SP, but inhibited TNF (60%) and CXCL8 (45%) secretion from LAD2 cells stimulated by IL-33. Fluorescein-conjugated CS (CS-F) was internalized by LAD2 cells only at 37 °C, but not 4 °C, indicating it occurred by endocytosis. DS and Hep inhibited IL-33-stimulated secretion of TNF and CXCL8 to a similar extent as CS. None of the GAGs tested inhibited IL-33-stimulated gene expression of either TNF or CXCL8. There was no effect of CS on ionomycin-stimulated calcium influx. There was also no effect of CS on surface expression of the IL-33 receptor, ST2. Neutralization of the hyaluronan receptor CD44 did not affect the internalization of CS-F. The findings in this article show that CS inhibits secretion of TNF and CXCL8 from human cultured MC stimulated by IL-33. CS could be formulated for systemic or topical treatment of allergic or inflammatory diseases, such as atopic dermatitis, cutaneous mastocytosis, and psoriasis. © 2018 BioFactors, 45(1):49-61, 2019.

Inhaled nebulised unfractionated heparin improves lung function in moderate to very severe COPD: A pilot study

BACKGROUND

COPD is an inflammatory airway disease characterised by progressive airflow limitation and air trapping, leading to lung hyperinflation and exercise limitation. Acute worsening of symptoms, including dyspnea, cough and sputum production, occurs during exacerbations which are associated with significantly reduced health related quality of life, and increased morbidity and mortality. Chronic bronchial mucus production and productive cough are risk factors for exacerbations. Medicines targeting bronchoconstriction and airway inflammation are the current mainstays of COPD therapy. However, there is growing concern with an increased risk of pneumonia in patients with COPD receiving regular inhaled corticosteroids and there is therefore a need to find safer alternative treatments. Previous studies have indicated that inhalation of unfractionated heparin (UFH) treats local inflammation, mucus hypersecretion and lung injury, without systemic anticoagulation, and is safe. Therefore, our primary objective was to demonstrate that inhaled UFH significantly improves lung function (FEV₁) over 21 days of treatment in patients with COPD receiving pulmonary rehabilitation and that UFH provides a novel, safe and effective way of treating this complex disease.

METHODS

Forty patients with moderate to very severe COPD admitted to the IRCCS San Raffaele Pisana Hospital for 21 days pulmonary rehabilitation were randomised to receive nebulised inhaled UFH (75,000 or 150,000 IU BID) or placebo for 21 days. All patients also received nebulised salbutamol (1 mg) and beclomethasone dipropionate (400 μg) BID over the same period. Lung function was measured at day 0, 7, 14 and 21 of treatment and at a follow-up visit 7 days post-treatment. Exercise capacity (6MWT) and dyspnoea (Borg score) were measured before and after treatment. In pre-clinical studies, the ability of basic proteins found in COPD sputum to neutralise the anticoagulant activity of heparin was determined using the AMAX heparin assay kit.

MAIN RESULTS

At both doses, UFH significantly increased FVC following 7 days of treatment and 150,000 IU BID significantly increased FEV1 (+249 ± 69 ml compared with placebo) at this time, an effect maintained to the 28 day follow-up. Clinically significant improvement in exercise capacity and dyspnoea were seen after 21 days of treatment with both doses of UFH. There were no serious adverse events or effects on systemic coagulation. Pre-clinical studies demonstrated that the basic proteins lactoferrin, platelet factor-4 (PF-4), IL-8 and polyarginine, as a model of the eosinophil cationic protein (ECP), found in COPD sputum neutralise the anticoagulant activity of heparin.

CONCLUSION

Inhaled nebulised UFH is safe and provides additional clinical benefit for patients with moderate to very severe COPD through effects that are independent of its anticoagulant activity.

Heparin: new life for an old drug

Heparin is one of the oldest drugs, which nevertheless remains in widespread clinical use as an inhibitor of blood coagulation. The history of its identification a century ago unfolded amid one of the most fascinating scientific controversies turning around the distribution of credit for its discovery. The composition, purification and structure-function relationship of this naturally occurring glycosaminoglycan regarding its classical role as anticoagulant will be dealt with before proceeding to discuss its therapeutic potential in, among other, inflammatory and infectious disease, cancer treatment, cystic fibrosis and Alzheimer's disease. The first bibliographic reference hit using the words 'nanomedicine' and 'heparin' is as recent as 2008. Since then, nanomedical applications of heparin have experienced an exponential growth that will be discussed in detail, with particular emphasis on its antimalarial activity. Some of the most intriguing potential applications of heparin nanomedicines will be exposed, such as those contemplating the delivery of drugs to the mosquito stages of malaria parasites.

Inhaled Heparin: Therapeutic Efficacy and Recent Formulations

Heparin is well known for its anticoagulant and anti-inflammatory properties. Inhaled heparin regimens are increasingly being used to manage lung disease. It has been used to treat cystic fibrosis, thromboembolism, and pulmonary fibrosis, as well as bronchial asthma and asthma-induced airway hypersensitivity. Several preclinical studies attained some useful effects of heparin-administered, parenterally and through inhalation, treatment of lung disease. Besides, recent clinical trials suggest that inhaled heparin for lung diseases is beneficial and safe, but such data remain to be limited. In 2005, the orphan designation was granted by the European Commission for heparin sodium (inhalation use) for the treatment of cystic fibrosis. The positive results of heparin in the pulmonary route necessitate a focus on the preparation and evaluation of heparin in advanced drug delivery systems, namely nano/microparticles and liposomes. Through this pulmonary delivery, heparin is protected from enzymatic degradation within the airway. Heparin is thus passively targeted into the lungs, and long-lasting localized treatment is achieved. On the other hand, these systems have encountered several problems as follows: (1) polymers, such as poly-L-lactide-glycolic acid, poly (lactic acid), and chitosan, used to prepare heparin-loaded microparticle/nanoparticle (MP/NP) systems have not been granted approval for lung application by the FDA and (2) liposomal and NP formulation stability is the main problem of formulation design. We propose that additional in vitro and in vivo research is necessary to assess the clinical applicability of this treatment strategy. The present article discusses heparin treatments for lung diseases and the use of heparin and/or heparin-loaded drugs in advanced delivery systems through the pulmonary route.

Inhalational use of antithrombotics in humans: Review of the literature

INTRODUCTION

Off label use of anticoagulants is common. The association between fibrin deposition in the lungs and primary lung disease, injury or prematurity affords a strong theoretical basis for the potential benefit of antithrombotic therapies administered directly to the lung tissue. This review offers a critical appraisal of current evidence related to the inhalational administration of antithrombotic therapy in humans.

MATERIALS AND METHODS

An interrogation of 2 databases across a 13 year period of time was undertaken using key words selected a priori. Identified publications were categorized according to the following themes: 1. Inhaled antithrombotic therapy in healthy subjects 2. Inhaled antithrombotic therapy for vascular thromboprophylaxis 3. Inhaled antithrombotic therapy in smoke inhalation and lung injury 4. Inhaled antithrombotic therapy in asthma or allergy 5. Inhaled antithrombotic therapy for plastic bronchitis post-Fontan surgery 6. Inhaled antithrombotic therapy for other indications.

RESULTS

33 articles were identified consistent with the inclusion criteria developed for this review. Unfractionated heparin, LMWH, activated protein C and thrombolytic agents have been administered via the respiratory track, with asthma and smoke inhalation/lung injury being the most frequently investigated clinical scenarios described. All studies reported had significant methodological limitations.

CONCLUSIONS

The safety and clinical utility of inhaled antithrombotic therapies have not been adequately investigated to support the generation of any firm evidence. This review highlights where inhaled antithrombotic therapies have shown promise and importantly, the further research required to confirm mechanism of action and a definitive risk: benefit profile.

The physiologic and therapeutic role of heparin in implantation and placentation

Implantation, trophoblast development and placentation are crucial processes in the establishment and development of normal pregnancy. Abnormalities of these processes can lead to pregnancy complications known as the great obstetrical syndromes: preeclampsia, intrauterine growth restriction, fetal demise, premature prelabor rupture of membranes, preterm labor, and recurrent pregnancy loss. There is mounting evidence regarding the physiological and therapeutic role of heparins in the establishment of normal gestation and as a modality for treatment and prevention of pregnancy complications. In this review, we will summarize the properties and the physiological contributions of heparins to the success of implantation, placentation and normal pregnancy.

Low-molecular-weight heparin and unfractionated heparin decrease Th-1, 2, and 17 expressions

Background

We evaluated the effects of T helper cell differentiation in a mite-allergic animal model treated with inhaled heparins of different molecular weight.

Method

BALB/c mice were divided into four groups: 1. Control, 2. Mite intratracheal (mIT), 3. Inhaled heparin (hIN), 4. Inhaled low-molecular-weight heparin (lmwhIN). Groups 2, 3, and 4 were sensitized twice with Der p allergen subcutaneously on day 1 and day 8. Der p allergen was administered intratracheally on day 15. Groups 3 and 4 were treated with heparin or low-molecular-weight (lmw) heparin intranasally from day 1 to 22. Splenocytes from sacrificed mice stimulated with 16 µg/ml of Der p were cultured for 72 hours. Supernatants of splenocyte were collected to analyze the effect of Interleukin (IL)17-A/F, Interferon(IFN)-γ, IL-4, IL-13, and IL-10. Serum was also collected for Der P-specific IgE level on day 23. Total RNA was extracted from spleen tissue for mRNA expression. Gene expression of Foxp3, IL-10 IFN-γ, GATA3, IL-5, and RORγt were analyzed.

Results

Both hIN and lmwhIN groups had lower serum IgE level than that of the mIT group (both p<0.0001). Both hIN and lmwhIN groups showed significantly decreased transcripts of GATA-3, IFN-γ, IL-5, and RORγt mRNA in their spleen. Regarding the supernatant of splenocyte culture stimulated with Der p, compared with the mIT group, there were significant decreases in IL-17A/F, IFN-γ, IL-4, IL-13, and IL-10 secretion in inhaled hIN and lmwhIN groups.

Conclusions

From this balb/c mice study, the analyses of mRNA and cytokines revealed that both intranasal heparin and lmw heparin treatment decreased the expression of Th1, Th2, and Th17 in spleen. The underlying mechanism(s) warrant further studies.

Non-anticoagulant derivatives of heparin for the management of asthma: distant dream or close reality?

INTRODUCTION

Approximately 300 million people worldwide are currently affected by asthma. Improvements in the understanding of the mechanisms involved in such inflammatory airway disorders has led to the recognition of new therapeutic approaches. Heparin, a widely used anticoagulant, has been shown to be beneficial in the management of asthma. It belongs to the family of highly sulphated polysaccharides referred to as glycosaminoglycans, containing a heterogeneous mixture of both anticoagulant and non-anticoagulant polysaccharides. Experimental findings have suggested that heparin has potential anti-asthmatic properties owing to the ability of its non-anticoagulant oligosaccharides to bind and modulate the activity of a wide range of biological molecules involved in the inflammatory process.

AREAS COVERED

This review focuses on the potential mechanisms of action and clinical application of heparin as an anti-inflammatory agent for the management of asthma.

EXPERT OPINION

Heparin may play a significant role in the management of asthma. However, these properties are often hindered by the presence of anticoagulant oligosaccharides, which possess a significant risk of bleeding. Therefore, its therapeutic potential must be explored using well-designed clinical studies that focus on identifying and isolating the anti-inflammatory oligosaccharides of heparin and further elucidating the structure and mechanisms of actions of these non-anticoagulant oligosaccharides.

Heparin protects BALB/c mice from mite-induced airway allergic inflammation

More and more studies have demonstrated the anti-inflammatory effects of heparin. However, in the aspect of allergic airway inflammation, data about its daily use in animal model is scarce. To evaluate the efficacy of 22-day intranasal heparin administration in mite-induced airway allergic inflammation in BALB/c mice, the murine model of house dust-mite allergen-induced asthma was used to assess the effect of heparin (h) and low molecular weight heparin (l mwh) administered intra-nasally (IN) throughout the full study period (22 days). Effects were monitored by histopathology, cell counts in broncho-alveolar lavage fluid (BALF), local cytokine production, serum, specific antibody levels, and airway resistance measurements. Compared to the positive control group, both hIN and lmwhIN groups had lower peri-bronchiolar/alveolar inflammatory pathology score and lower goblet cell scores (p less than 0.01); lower eosinophil and neutrophil counts in BALF (p less than 0.0001); and lower cytokine levels including IL-17A/F, IL-5, IL-13, IL-8 and eotaxin in lung tissue (p less than 0.001). Serum Der p-specific IgE level was also lower in heparin-treated groups (p less than 0.004). The two heparin-treated groups also revealed lower value of Penh after Mch stimulation. In conclusion, heparin and lmw heparin decrease serum Der p-specific IgE level and possess anti-inflammatory effects on mite-induced airway allergic inflammation model in BALB/c mice.

Heparin treatment for allergic conjunctivitis in the experimental BALB/c model

PURPOSE

To compare the inhibitory effects of dexamethasone and heparin on the infiltration of mast cells in the conjunctiva by using a mouse allergic conjunctivitis model.

METHODS

24 Balb/c mice were divided into four groups: allergy group (positive control), dexamethasone group, heparin group, and negative control group, as groups 1, 2, 3, and 4, respectively. Each group comprised 6 mice, and experimental allergic conjunctivitis was developed in groups 1, 2, and 3. The mice in group 2 were treated with topical 0.1% dexamethasone eye ointment, and the mice in group 3 were treated topically with 5,000 IU/ml standard heparin. Both dexamethasone and heparin were instilled once a day for 4 days. Hanks' balanced salt solution was dropped into both eyes of the mice in group 4 instead of dexamethasone or heparin. Eyeballs and eyelids were removed from the mice in all groups while one eye of each animal was used for histopathological, the other for molecular biological examination.

RESULTS

Mast cells, infiltrating the subconjunctival tissue, were significantly lower in group 2 (p < 0.0001), group 3 (p < 0.0001) and group 4 (p < 0.0001) when compared to group 1.

CONCLUSIONS

Topical heparin could be a viable option in treating IgE-induced allergic eye disease since it is found to be as effective as topical dexamethasone in experimental acute allergic eye disease.

Inhibition of allergic airway responses by heparin derived oligosaccharides: identification of a tetrasaccharide sequence

Background

Previous studies showed that heparin's anti-allergic activity is molecular weight dependent and resides in oligosaccharide fractions of <2500 daltons.

Objective

To investigate the structural sequence of heparin's anti-allergic domain, we used nitrous acid depolymerization of porcine heparin to prepare an oligosaccharide, and then fractionated it into disaccharide, tetrasaccharide, hexasaccharide, and octasaccharide fractions. The anti-allergic activity of each oligosaccharide fraction was tested in allergic sheep.

Methods

Allergic sheep without (acute responder) and with late airway responses (LAR; dual responder) were challenged with Ascaris suum antigen with and without inhaled oligosaccharide pretreatment and the effects on specific lung resistance and airway hyperresponsiveness (AHR) to carbachol determined. Additional inflammatory cell recruitment studies were performed in immunized ovalbumin-challenged BALB/C mice with and without treatment.

Results

The inhaled tetrasaccharide fraction was the minimal effective chain length to show anti-allergic activity. This fraction showed activity in both groups of sheep; it was also effective in inhibiting LAR and AHR, when administered after the antigen challenge. Tetrasaccharide failed to modify the bronchoconstrictor responses to airway smooth muscle agonists (histamine, carbachol and LTD₄), and had no effect on antigen-induced histamine release in bronchoalveolar lavage fluid in sheep. In mice, inhaled tetrasaccharide also attenuated the ovalbumin-induced peribronchial inflammatory response and eosinophil influx in the bronchoalveolar lavage fluid. Chemical analysis identified the active structure to be a pentasulfated tetrasaccharide ([IdoU2S (1→4)GlcNS6S (1→4) IdoU2S (1→4) AMan-6S]) which lacked anti-coagulant activity.

Conclusions

These results demonstrate that heparin tetrasaccharide possesses potent anti-allergic and anti-inflammatory properties, and that the domains responsible for anti-allergic and anti-coagulant activity are distinctly different.

Asthma and coagulation

Asthma is a chronic airway disease characterized by paroxysmal airflow obstruction evoked by irritative stimuli on a background of allergic lung inflammation. Currently, there is no cure for asthma, only symptomatic treatment. In recent years, our understanding of the involvement of coagulation and anticoagulant pathways, the fibrinolytic system, and platelets in the pathophysiology of asthma has increased considerably. Asthma is associated with a procoagulant state in the bronchoalveolar space, further aggravated by impaired local activities of the anticoagulant protein C system and fibrinolysis. Protease-activated receptors have been implicated as the molecular link between coagulation and allergic inflammation in asthma. This review summarizes current knowledge of the impact of the disturbed hemostatic balance in the lungs on asthma severity and manifestations and identifies new possible targets for asthma treatment.

Hyaluronic acid : perspectives in lung diseases

Hyaluronic acid (HA) is a non-sulphated glycosaminoglycan. It is a natural polymer characterised by a coiled linear chain in particularly well-hydrated configuration composed of repeating disaccaride units. In mammals, its molecular weight can be extremely wide, ranging from 20 to 4,000 kDa. High molecular mass forms are provided with anti-inflammatory properties. A unique characteristic of HA is hydration (up to 6,000 molecules water/molecule of HA) with a major role in the regulation of fluid balance in the interstitium, a fundamental activity on the amorphous colloidal matrix gluing connective cell and fibers, and many other biological functions including lubrication, solute transport and microcirculatory exchange. HA has been widely used in the treatment of eye, ear, joint and skin disorders; in the last 15 years HA has been also proposed successfully in the treatment of a number of lung diseases in vitro, experimental animals and humans. In particular, inhaled HA at relatively high molecular weight has been proven to prevent bronchoconstiction induced in asthmatics by direct and indirect challenges such as inhalation of methacholine, inhalation of ultrasonically nebulised distilled water, muscular exercise. More recently, in patients affected by chronic obstructive pulmonary diseases, we have demonstrated that repeated administrations of inhaled HA (daily, for 8 weeks) induce significant increase in bronchial patency as well as progressive lung deflation with decrease of residual volume. In conclusion there are elements that can let us state that is perhaps time to change the focus to connective tissue and extracellular matrix substances such as HA, in order to prevent and treat chronic lung diseases.

A potential nanomedicine consisting of heparin-loaded polysaccharide nanocarriers for the treatment of asthma

A new nanomedicine consisting of chitosan/carboxymethyl-β-cyclodextrin loaded with unfractioned or low-molecular-weight heparin is described and its potential in asthma treatment is evaluated. The nanoparticles are prepared by ionotropic gelation showing a size that between 221 and 729 nm with a positive zeta potential. The drug association efficiency is higher than 70%. Developed nanosystems are stable in Hank's balanced salt solution at pH = 6.4, releasing the drug slowly. Ex vivo assays show that nanocarriers lead to an improvement of heparin preventing mast cell degranulation. These results agree with the effective cellular internalization of the fluorescently labeled nanocarriers, and suggest these nanomedicines as promising formulations for asthma treatment.

Heparin and low-molecular weight heparins in thrombosis and beyond

Heparin and its improved version, low-molecular weight heparin (LMWH), are known to exert polypharmacological effects at various levels. Early studies focused on the plasma anti-Xa and anti-IIa pharmacodynamics of different LMWHs. Other important pharmacodynamic parameters for heparin and LMWH, including effects on vascular tissue factor pathway inhibitor (TFPI) release, inhibition of inflammation through NFkappaB, inhibition of key matrix-degrading enzymes, selectin modulation, inhibition of platelet-cancer cell interactions, and inflammatory cell adhesion, help explain the diverse clinical impact of this class of agents in thrombosis and beyond.

The 'sweet' and 'bitter' involvement of glycosaminoglycans in lung diseases: pharmacotherapeutic relevance

The extracellular matrix (ECM) plays a significant role in the structure and function of the lung. The ECM is a three-dimensional fibre mesh, comprised of various interconnected and intercalated macromolecules, among which are the glycosaminoglycans (GAG). GAG are long, linear and highly charged, heterogeneous polysaccharides that are composed of a variable number of repeating disaccharide units (macromolecular sugars) and most of them, as their name implies, have a sweet taste. In the lung, GAG support the structure of the interstitium, the subepithelial tissue and the bronchial walls, and are secreted in the airway secretions. Besides maintaining lung tissue structure, GAG also play an important role in lung function as they regulate hydration and water homeostasis, modulate the inflammatory response and influence lung tissue repair and remodelling. However, depending on their size and/or degree of sulphation, and their immobilization or solubilization in the ECM, specific GAG in the lung either live up to their sweet taste/name, supporting normal lung physiology, or they are associated to 'bitter' effects, related to lung pathology. The present review discusses the biological role of GAG in the lung as well as the involvement of these molecules in various respiratory diseases. Given the great structural diversity of GAG, understanding the changes in GAG expression that occur in lung diseases may lead to novel targets for pharmacological intervention in order to prevent and/or to treat a range of lung diseases.

The effect of IVX-0142, a heparin-derived hypersulfated disaccharide, on the allergic airway responses in asthma

BACKGROUND

IVX-0142 is a heparin-derived hypersulfated disaccharide devoid of anticoagulant activity while possessing anti-allergic and anti-inflammatory activity in preclinical studies. In a proof-of-concept study, the allergen inhalation challenge model was used to investigate the effect of IVX-0142 in mild atopic asthma.

METHODS

Nineteen subjects, not on controller medications, were randomized to an evaluator-blind, placebo-controlled, cross-over study. The effect of a single nebulized dose of IVX-0142 (80 mg) or placebo administered 30 min prior to allergen inhalation was evaluated on the allergic airway responses, airway responsiveness, and airway inflammation.

RESULTS

When compared with placebo, 14 and 13 subjects experienced a relatively smaller maximum fall in forced expiratory volume in 1 s (maxFEV(1)%) for the early airway response (EAR) and late airway response (LAR) with IVX-0142, respectively (P < 0.01). The degree of attenuation in the EAR [maxFEV(1)% (mean +/- SE) 26.5 +/- 2.8%vs placebo 31.0 +/- 2.8%, P = 0.059] and LAR (15.6 +/- 2.9%vs placebo 19.0 +/- 2.9%, P = 0.24) with IVX-0142, however, was small and did not reach statistical significance compared with placebo. Similarly, a trend in the attenuation of allergen-induced increase in the absolute sputum cell counts was also observed. No difference in the allergen-induced increase in airway hyper-responsiveness and exhaled nitric oxide was noticed.

CONCLUSIONS

The majority of mild atopic asthmatics demonstrated a reduction in the EAR and LAR to IVX-0142. However, the treatment effect observed with a single prechallenge dose of IVX-0142 was small and heterogeneous. The potential anti-allergic and anti-inflammatory effects using multiple higher doses need to be evaluated.

In vivo effect of adhesion inhibitor heparin on Legionella pneumophila pathogenesis in a murine pneumonia model

OBJECTIVE

To examine the effect of intratracheal heparin instillation on Legionella pneumophila-related acute lung injury (ALI) and systemic dissemination.

DESIGN

Prospective, controlled experimental study.

SETTING

University research laboratory.

INTERVENTIONS

A/J mice received 5 microg of sulfated heparin intratracheally co-instilled with 10(6) or 10(8) colony-forming units (CFU) of a virulent isolate of L. pneumophila.

MEASUREMENTS AND RESULTS

ALI was assessed in control groups (PBS and PBS-heparin) and on days 1, 2 and 3 post-infection, in terms of the lung wet-to-dry (W/D) weight ratios and of lung endothelial permeability to radio-labeled albumin (Perm-I(125)). Lung bacterial loads were measured and systemic spread was assessed by blood and target organ culture. The alveolar inflammatory response was evaluated by measuring the cytokine levels (TNF-alpha, IFN-gamma, IL-6 and IL-12p70) in bronchoalveolar lavage fluids (BALF). Co-instilled heparin improved mouse survival after the 10(8) CFU challenge (p < 0.01). On day 2, heparin co-instillation significantly reduced the W/D ratio and Perm-I(125) (p < 0.01 and p < 0.001 respectively), improved lung bacterial clearance (p < 0.001), prevented systemic dissemination (blood, liver, spleen, kidneys and brain cultures, all p < 0.05) and significantly increased IFN-gamma and IL-12p70 levels in BALF (p < 0.05).

CONCLUSIONS

Heparin co-instillation during intratracheal L. pneumophila challenge has a protective effect on the alveolar-capillary barrier and prevents bacterial dissemination. These results tend to confirm the competitive inhibition by heparin of L. pneumophila attachment to lung epithelium in vivo, and point to the possible involvement of a heparan-sulfate adhesin in L. pneumophila binding to pneumocytes.

New drugs targeting Th2 lymphocytes in asthma

Asthma represents a profound worldwide public health problem. The most effective anti-asthmatic drugs currently available include inhaled beta2-agonists and glucocorticoids and control asthma in about 90-95% of patients. The current asthma therapies are not cures and symptoms return soon after treatment is stopped even after long term therapy. Although glucocorticoids are highly effective in controlling the inflammatory process in asthma, they appear to have little effect on the lower airway remodelling processes that appear to play a role in the pathophysiology of asthma at currently prescribed doses. The development of novel drugs may allow resolution of these changes. In addition, severe glucocorticoid-dependent and resistant asthma presents a great clinical burden and reducing the side-effects of glucocorticoids using novel steroid-sparing agents is needed. Furthermore, the mechanisms involved in the persistence of inflammation are poorly understood and the reasons why some patients have severe life threatening asthma and others have very mild disease are still unknown. Drug development for asthma has been directed at improving currently available drugs and findings new compounds that usually target the Th2-driven airway inflammatory response. Considering the apparently central role of T lymphocytes in the pathogenesis of asthma, drugs targeting disease-inducing Th2 cells are promising therapeutic strategies. However, although animal models of asthma suggest that this is feasible, the translation of these types of studies for the treatment of human asthma remains poor due to the limitations of the models currently used. The myriad of new compounds that are in development directed to modulate Th2 cells recruitment and/or activation will clarify in the near future the relative importance of these cells and their mediators in the complex interactions with the other pro-inflammatory/anti-inflammatory cells and mediators responsible of the different asthmatic phenotypes. Some of these new Th2-oriented strategies may in the future not only control symptoms and modify the natural course of asthma, but also potentially prevent or cure the disease.

Oral corticosteroid-dependent asthma: a 30-year review

OBJECTIVE

To identify novel aspects of the pathogenesis, therapeutic options, and prophylaxis measures of corticosteroid-dependent asthma.

DATA SOURCES

PubMed searches were undertaken of studies published between 1966 and 2006 on the pathogenesis of and corticosteroid-sparing therapies for corticosteroid-dependent asthma. Identified review articles were surveyed for additional and earlier citations. Recent American Academy of Asthma, Allergy, and Immunology meeting abstracts were also searched to identify other recently published and unpublished studies.

STUDY SELECTION

Inclusion of studies in the review was decided by simple agreement of both reviewers, who independently read the "Methods" and "Discussion" sections of articles identified using the search strategy. Quality assessment was performed by the 2 reviewers.

RESULTS

High-dose inhaled corticosteroids are the first-line option for corticosteroid-dependent asthmatic patients with clear efficacy. Omalizumab is effective in reducing oral corticosteroid requirements in allergic asthma. Methotrexate, gold, and cyclosporine have corticosteroid-sparing effects clinically that must be weighed against a serious adverse effect profile. Nebulized diuretics and lidocaine, with a low adverse effect profile, offer promising results but require further study. Clarithromycin and telithromycin seem to have an independent mechanism of inflammatory modulation, but their effect on corticosteroid-dependent asthma remains to be seen. Etanercept offers only early clinical evidence of a role in corticosteroid-dependent asthma.

CONCLUSIONS

With no clear consensus on corticosteroid-sparing treatment in corticosteroid-dependent asthmatic patients, systemic glucocorticoids remain the foremost therapy, with adverse effects that require monitoring and prophylaxis.

The anti-inflammatory effects of heparin and related compounds

Heparin is a glycosaminoglycan well known for its anticoagulant properties. In addition, heparin possesses anti-inflammatory effects. Although the mechanisms responsible for the anticoagulant effects of heparin are well understood, those underlying its anti-inflammatory effects are not. This review presents some of the evidence from clinical and animal studies supporting an anti-inflammatory role for heparin and heparin-related derivatives. Potential mechanisms by which heparin can exert its anti-inflammatory effects are discussed. The clinical use of heparin as an anti-inflammatory agent has been held back by the fear of bleeding. Development of nonanticoagulant heparins or heparin derivatives should mitigate this concern.

Alterations in cytoskeletal and immune function-related proteome profiles in whole rat lung following intratracheal instillation of heparin

Background

Heparin has been shown to modify fundamental biologic processes ranging from blood coagulation and cell proliferation to fibrogenesis and asthma. The goal of this study was to identify specific or broad biologic responses of the rat lung to intratracheal instillation of heparin by targeted proteomic analysis.

Methods

Rats were given either aerosolized 500 μg heparin in 250 μl saline or saline alone. Lungs were harvested at 0, 24, or 96 hours post-treatment and isolated proteins analyzed by two-dimensional gel electrophoresis. Proteins which increased and decreased significantly in treated groups above controls were then selected for identification by mass spectrometry.

Results

Although heparin treatments resulted in a general reduction in cytosolic protein expression, there were significant increases within members of discrete groups of proteins. At 24 hours, proteins which function in cytoskeletal organization and in calcium signaling were up-regulated between 2- and 27-fold above baseline and untreated controls. Increased proteins include annexins V and VI, septin 2, capping G protein, actin-related protein 3, moesin, RhoGDP dissociation inhibitor, and calcyclin. A group of proteins relating to immune response and tumor suppressor function were either up-regulated (tumor suppressor p30/hyaluronic acid binding protein-1, Parkinson disease protein 7, proteosome 28 subunit/interferon-γ inducible protein, and proteosome subunit macropain α-1) or strongly down-regulated (transgelin). At 96 hours, most proteins that had increased at 24 hours remained elevated but to a much lesser degree.

Conclusion

These cumulative observations demonstrate that whole lung heparin treatment results in significant up-regulation of selected groups of proteins, primarily those related to cytoskeletal reorganization and immune function, which may prove to be relevant biomarkers useful in analysis of lung exposures/treatments as well as in system biology studies.

Unlabeled uses of nebulized medications

PURPOSE

The uses, dosing recommendations, benefits, and disadvantages of unlabeled drugs administered by nebulization are reviewed.

SUMMARY

Nebulization is gaining popularity as a treatment alternative, and many drugs are used unlabeled in a nebulized form, including the opioids, lidocaine, magnesium sulfate, amphotericin B, and colistin. The opioids are frequently used to treat dyspnea in end-stage diseases. Common dosages include 1-2 mg every two hours as needed for hydromorphone and 25-50 microg every two hours for fentanyl citrate. Lidocaine can be used to relieve bronchoconstriction and cough symptoms as well as acting as a local anesthetic. It is typically given in a dose between 20 and 160 mg. Nebulized magnesium sulfate can be used in managing acute asthma and is given in dosages between 125 and 250 mg every 20 minutes, with no more than four consecutive doses. Nebulized amphotericin B can be used to prevent infections in immunocompromised patients. A typical amphotericin B regimen is 25 mg every 24 hours. Nebulized colistin is being studied in the prevention and treatment of gram-negative infections and in patients awaiting lung transplants. Colistin is often given as 75 mg every 12 hours to combat infections.

CONCLUSION

Unlabeled nebulization of opioids, lidocaine, magnesium, amphotericin B, and colistin is an alternative method of treatment for patients with pulmonary problems or infections or for those undergoing bronchoscopy. More research is needed to develop guidelines for their use since nebulization may provide benefits to many patients who otherwise cannot be treated or would be at risk of systemic adverse effects of the drugs.

Aerosolised hyaluronic acid prevents exercise-induced bronchoconstriction, suggesting novel hypotheses on the correction of matrix defects in asthma

Hyaluronic acid (HA), a biopolymer, member of the family of the glycosaminoglicanes (GAGs) is one of the major natural components of the connective amorphous matrix. The lungs, together with skin and intestine, contain >50% of HA of the body: it provides to several biologic functions and presents the unique capacity to link and retain a particularly relevant number of water molecules. Since other GAGs have been proven to be provided with anti-asthmatic properties and HA has been employed with positive results by intra-tracheal instillation in experimental models of lung emphysema and COPD, we have explored the efficacy of the pre-administered aerosol of HA (compared to placebo) in preventing in asthmatic patients the bronchoconstriction induced by a challenge test such as that obtained with muscular exercise. In a randomised, cross-over, single-blind study design, saline as placebo (P) or HA have been administered by aerosol, in two non-consecutive days, 30 min prior to the beginning of the challenge (10 min free running), to 14 patients (13-36 years old; 7 teenagers, 7 young adults; 11 males, 3 females; 12 allergic, 2 non-allergic), all suffering from mild bronchial asthma. The bronchoconstrictive effect induced by the muscular exercise has been relevant and statistically significant. With the P pre-treatment, the average FEV1 measured 5 min after the end of exercise was reduced by 36.14% from the baseline FEV1. Pre-treatment with HA determined a partial but clear-cut protection of the FEV1 impairment due to the challenge: the average post-challenge FEV1 resulted to be 12.43% less than the pre-challenge baseline value. No significant difference was observed in the level of HA protection in the subgroup of teenagers when compared to that of young adults. The protection induced by HA, when compared with P, resulted particularly significant by the statistical point of view (p < 0.0001). We conclude that aerosol HA administration significantly reduces the bronchial hyper-reactivity to muscular exercise in asthmatics. Such effect could be attributed to the correction of the pathological remodelling, one of the main features of asthma: a correction which could be attributed to the unique physicochemical properties of this major component of the loose connective amorphous matrix of the airways, which is undoubtedly involved in the remodelling process.

Inhaled hyaluronic acid against exercise-induced bronchoconstriction in asthma

Hyaluronic acid (HA) is a polysaccharide that is present in human tissues and body fluids. HA has various functions, including a barrier effect, water homeostasis, stabilizing the extracellular matrix, increased mucociliary clearance and elastin injury prevention. It may therefore exert prophylactic activity in the treatment of asthma. We tested the hypothesis that HA inhalation will prevent exercise-induced bronchoconstriction (EIB) in a randomised double-blinded placebo-controlled crossover study. Sixteen asthmatic patients with EIB were included in the study (mean (SD)) (age 24.5 (7.3) yr, FEV1 88.6 (11.3) %predicted, PC20 methacholine (g-mean (SD in DD)) 0.4 (1.5) mg/ml). On two separate visits an exercise challenge was performed 15 min post-inhalation of either HA (3 ml 0.1% in PBS) or placebo (3 ml PBS). The maximum fall in FEV1 and the AUC 30 min post-exercise were used as outcomes. After inhalation of both HA and placebo, baseline FEV1 decreased significantly (HA 4.1 (3.1)%, placebo 2.9 (4.1)%, P<0.017). The maximum fall in FEV1 following exercise challenge was not significantly different between HA versus placebo (median HA 22.50%, placebo 27.20%, P=0.379), as was the AUC (median HA 379.3 min*%fall, placebo 498.9 min*%fall, P=0.501). We conclude that at the current dose, inhaled HA does not significantly protect against EIB. This suggests that HA is not effective as a prophylaxis for EIB in patients with asthma.

Endogenous attenuation of allergic lung inflammation by syndecan-1

The airway plays a vital role in allergic lung diseases by responding to inhaled allergens and initiating allergic inflammation. Various proinflammatory functions of the airway epithelium have been identified, but, equally important, anti-inflammatory mechanisms must also exist. We show in this study that syndecan-1, the major heparan sulfate proteoglycan of epithelial cells, attenuates allergic lung inflammation. Our results show that syndecan-1-null mice instilled with allergens exhibit exaggerated airway hyperresponsiveness, glycoprotein hypersecretion, eosinophilia, and lung IL-4 responses. However, administration of purified syndecan-1 ectodomains, but not ectodomain core proteins devoid of heparan sulfate, significantly inhibits these inflammatory responses. Furthermore, syndecan-1 ectodomains are shed into the airway when wild-type mice are intranasally instilled with several biochemically distinct inducers of allergic lung inflammation. Our results also show that syndecan-1 ectodomains bind to the CC chemokines (CCL7, CCL11, and CCL17) implicated in allergic diseases, inhibit CC chemokine-mediated T cell migration, and suppress allergen-induced accumulation of Th2 cells in the lung through their heparan sulfate chains. Together, these findings uncover an endogenous anti-inflammatory mechanism of the airway epithelium where syndecan-1 ectodomains attenuate allergic lung inflammation via suppression of CC chemokine-mediated Th2 cell recruitment to the lung.

Heparin normalizes allergen-induced nitric oxide deficiency and airway hyperresponsiveness

It has been established that polycations cause airway hyperresponsiveness (AHR) to methacholine by inducing a deficiency of constitutive nitric oxide synthase (cNOS)-derived bronchodilating nitric oxide (NO). Since a deficiency of cNOS-derived NO also contributes to allergen-induced AHR after the early asthmatic reaction (EAR) and since this AHR is associated with the release of polycationic proteins from infiltrated eosinophils in the airways, we hypothesized that endogenous polycations underlie or at least contribute to the allergen-induced NO deficiency and AHR. Using a guinea-pig model of allergic asthma, we addressed this hypothesis by examining the effect of the polyanion heparin, acting as a polycation antagonist, on the responsiveness to methacholine of isolated perfused tracheae from unchallenged control animals and from animals 6 h after ovalbumin challenge, that is, after the EAR. A 2.0-fold AHR (P<0.001) to intraluminal administration of methacholine was observed in airways from allergen-challenged animals compared to control. Incubation of these airways with 250 U ml(-1) heparin completely normalized the observed hyperresponsiveness (P<0.001), whereas the responsiveness to methacholine of airways from unchallenged control animals was not affected. The effect of heparin on airways from allergen-challenged guinea-pigs was dose-dependently (0.1 and 1.0 mM) reversed by the NOS inhibitor L-NAME (P<0.01). These results indicate that endogenous (presumably eosinophil-derived) polycations are involved in allergen-induced NO deficiency and AHR after the EAR, probably by inhibition of l-arginine transport.

Inibidores de fosfodiesterases: novas perspectivas de uma antiga terapia na asma?

A asma é uma doença inflamatória crônica com níveis variados de obstrução ao fluxo aéreo e diferentes formas de apresentação. Seu tratamento vem sendo modificado com a evolução do conhecimento sobre sua patogenia. A inflamação das vias aéreas, que é modulada por determinantes genéticos e ambientais, resulta na alteração definitiva da arquitetura da via aérea (remodelamento). O padrão inflamatório da asma é de natureza multicelular, envolvendo mastócitos, neutrófilos, eosinófilos, linfócitos T, células musculares e epiteliais. Diversas citocinas e quimiocinas contribuem para a orquestração do processo inflamatório. O reconhecimento do papel crítico da inflamação, que está associada à gravidade da doença, vem direcionando o eixo do tratamento para a prevenção ou para o bloqueio das alterações inflamatórias. Nesse sentido, além dos agentes beta2-adrenérgicos, da teofilina e dos corticosteróides, novos fármacos vêm sendo estudados. Dentre eles, os inibidores específicos de fosfodiesterases vêm apresentando resultados promissores. A partir dos resultados obtidos com a segunda geração dessas substâncias, pode-se imaginar que, em breve, elas representarão uma nova opção para o tratamento da asma.

Muscarinic acetylcholine receptors and airway diseases

Parasympathetic nerves provide the dominant autonomic innervation of the airways. Release of acetylcholine from parasympathetic nerves activates postjunctional muscarinic receptors present on airway smooth muscle, submucosal glands, and blood vessels to cause bronchoconstriction, mucus secretion, and vasodilatation, respectively. Acetylcholine also feeds back onto prejunctional muscarinic receptors to enhance or inhibit further acetylcholine release. In asthma and chronic obstructive pulmonary disease, bronchoconstriction and mucus secretion is increased and the airways are hyperresponsive to contractile agents. These changes are due to increased parasympathetic nerve activity. The number and function of postjunctional muscarinic receptors in the airways are unchanged in animal models of asthma. Rather, it is the supply of acetylcholine to the postjunctional cells (smooth muscle and submucosal gland) that is increased. The increase in acetylcholine release occurs because prejunctional, inhibitory M(2) muscarinic receptors on the parasympathetic nerves are dysfunctional. M(2) muscarinic receptor dysfunction and subsequent airway hyperreactivity have been demonstrated to occur in animals in response to a variety of triggers, including antigen challenge, virus infection, ozone exposure, and vitamin A deficiency. In humans, there is evidence that loss of M(2) muscarinic receptor function is related to asthma. The mechanisms by which neuronal M(2) muscarinic receptor function is lost and its relevance to human airway disease are discussed in this review.

Exercise-induced asthma: diagnosis and management

OBJECTIVE

To review the diagnosis and management of exercise-induced asthma (EIA).

DATA SOURCES

Computer-assisted literature searches on MEDLINE for articles, abstracts, and other relevant data on exercise-induced asthma

STUDY SELECTION

Published articles, abstracts, and conference proceedings were selected.

RESULTS

EIA is seen in 40 to 90% of asthmatic patients. Exercise can be the sole trigger or be one of multiple triggers of asthma exacerbations. A good history and physical examination can diagnose most cases of EIA. Spirometry can confirm the diagnosis. Exercise testing may be necessary in certain cases. Prevention through both pharmacologic and nonpharmacologic measures is the key to EIA management. Inhaled beta-agonists remain the medications of choice for EIA prophylaxis. Inhaled cromolyn and antileukotrienes are alternatives. Good long-term control of asthma with anti-inflammatory medications such as inhaled steroids will also decrease the incidence of EIA.

CONCLUSIONS

Early diagnosis and proper preventive and maintenance therapy can reduce episodes of EIA and enable patients to continue to engage in sports and lead an active life.

Heparin inhibits hyperventilation-induced late-phase hyperreactivity in dogs

Inhalation of heparin attenuates hyperventilation-induced bronchoconstriction in humans and dogs. The purpose of this study was to determine whether heparin inhibits the late-phase response to hyperventilation, which is characterized by increased peripheral airway resistance (RP), eicosanoid mediator production, neutrophilic/ eosinophilic inflammation, and airway hyperreactivity (AHR) at 5 h after dry air challenge (DAC). Fiberoptic bronchoscopy was used to record RP and airway reactivity (DeltaRP) to aerosol and intravenous histamine before and 5 h after DAC. Bronchoalveolar lavage fluid (BALF) cells and eicosanoid mediators were also measured approximately 5 h after DAC. DAC of vehicle-treated bronchi resulted in late-phase airway obstruction (approximately 120% increase over baseline RP), inflammation, increased BALF concentrations of leukotriene (LT) C(4), LTD(4), and LTE(4) and prostaglandin (PG)D(2), and AHR. Pretreatment with aerosolized heparin attenuated late-phase airway obstruction by approximately 50%, inhibited eosinophil infiltration, reduced BALF concentrations of LTC(4), LTD(4), and LTE(4) and PGD(2), and abolished AHR. We conclude that heparin inhibits hyperventilation-induced late-phase changes in peripheral airway function, and does so in part via the inhibition of eosinophil migration and eicosanoid mediator production and release.

Intranasal heparin reduces eosinophil recruitment after nasal allergen challenge in patients with allergic rhinitis

BACKGROUND

Recently, several studies have shown that heparin possesses various anti-inflammatory and antiallergic properties. It has been proposed that heparin might play an important role in limiting the inflammatory events associated with asthma and allergic rhinitis by neutralizing inflammatory mediators, such as eosinophil cationic protein and major basic protein, and by limiting eosinophil recruitment.

OBJECTIVE

To test the hypothesis that heparin can limit the extent and magnitude of eosinophilic inflammation, we examined the effect of inhaled intranasal heparin on nasal response to allergen challenge in 10 patients with allergic rhinitis.

METHODS

The capacity of heparin to reduce nasal response was studied by evaluating symptom score, eosinophil cationic protein concentration, and eosinophil counts in nasal lavage fluids 10, 60, and 360 minutes after allergen challenge.

RESULTS

Pretreatment with intranasal heparin produced a significant reduction in symptom score 10 minutes after allergen challenge and reduced the eosinophil influx at each time point after antigen challenge, statistical significance being reached 60 and 360 minutes after allergen challenge. Similarly, the amount of eosinophil cationic protein in the nasal wash was reduced at each time point; this reached statistical significance 360 minutes after allergic challenge.

CONCLUSION

Heparin was shown to provide protection with respect to nasal allergen challenge. The mechanism by which heparin produces its protective activity seems to be related to the neutralization of eosinophil cationic protein as well as to the reduction of eosinophil recruitment.

Effects of heparin on hypertonic potassium chloride-induced bronchoconstriction

BACKGROUND

Changes in bronchial osmolarity is a well-known factor for bronchoconstricion. Recenty, nonisotonic aerosols have begun to be used for the assessment of bronchial hyperreactivity. Hypertonic KCl can cause bronchoconstriction even in non-symptomatic asthmatic patients.

OBJECTIVE

To evaluate the protective role of heparin on hypertonic KCl-induced bronchospasm in asthma.

METHODS

Thirty-eight asthmatic patients were included in this double-blind, placebo-controlled study. On day 1 of the study, after performing the respiratory function test (RFT), patients had inhaled KCl 10% and RFTs were done after 20 minutes. On day 2 of the study, after the basal RFT, 18 patents inhaled NaCl 0.9% 0.2 mLkg solution. After the completion of this procedure, patients waited for 20 minutes and inhaled KCl 10% 10 mL, and RFTs were repeated 20 minutes later. The second group consisted of 20patients who inhaled heparn 1,000 units/kg after the RFTs were performed. Twenty minutes later, they inhaled KCl 10% and waited for 20 minutes. Finally, RFTs were done and compared with those from the other group.

RESULTS

In the control group, forced expiratory volume in one second (FEV1) decreased 17.4% on day 1 and 16.4% on day 2. In the heparin-treated group, FEV1 decreased 18.6% on day 1, but almost no change occurred after this group was treated with heparin before inhalation of hypertonic KCl on day 2.

CONCLUSIONS

Heparin was found to be highly protective against hypertonic KCl induced bronchospasm in bronchial asthma.

Glycosaminoglycans, airways inflammation and bronchial hyperresponsiveness

Glycosaminoglycans (GAGs) are large, polyanionic molecules expressed throughout the body. The GAG heparin, co-released with histamine, is synthesised by and stored exclusively in mast cells, whereas the closely related molecule heparan sulphate is expressed, as part of a proteoglycan, on cell surfaces and throughout tissue matrices. These molecules are increasingly thought to play a role in regulation of the inflammatory response and heparin, for many years, has been considered to hold potential in the treatment of diseases such as asthma. Heparin and related molecules have been found to exert antiinflammatory effects in a wide range of in vitro assays, animal models and, indeed, human patients. Moreover, the results of studies carried out to date indicate that the antiinflammatory activities of heparin are dissociable from its well-established anticoagulant nature, suggesting that the separation of these characteristics could yield novel antiinflammatory drugs which may be useful in the future treatment of diseases such as asthma

Glucosamine for migraine prophylaxis?

Following a fortuitous observation that migraine headaches ceased in a patient receiving glucosamine therapy for osteoarthritis, a further ten patients with migraine or migraine-like vascular headaches, refractory to established preventive or abortive therapies, have been treated with daily oral glucosamine. After a lag of 4-6 weeks, a substantial reduction in headache frequency and/or intensity has been noted; in some cases, the benefit appears to be dose-dependent. Since glucosamine can be a rate-limiting precursor for mucopolysaccharide synthesis, it is germane to note previous reports that heparin and pentosan polysulfate may have migraine-preventive activity. There is reason to suspect that mast cells are central mediators of the neurogenic inflammation associated with migraine and cluster headaches. The heparin produced by mast cells may function to provide feedback down-regulation of mast cell activation, and exerts a range of other anti-inflammatory effects. We postulate that supplemental glucosamine can boost mast cell heparin synthesis - perhaps correcting a functional heparin deficiency - thereby preventing or ameliorating the neurogenic inflammation that mediates pain in vascular headache. Whether or not this idea has validity, a controlled study of glucosamine for migraine prophylaxis appears to be warranted.

Advances in immunopharmacology of asthma

Asthma is a chronic inflammatory disease characterized by airway hyperresponsiveness and recurrent reversible airway obstruction. As there appears to be a preponderance of T-helper 2 (Th2) cells over Th1 cells in asthma, more attention has been focused on the role of Th2-derived cytokines such as interleukin (IL)-4 and IL-5 and their corresponding signaling pathways in the pathophysiology of the disease. These complex pathways may involve the activation of signal transducers and activators of transcription (STATs) and nuclear factor-kappaB (NF-kappaB). On the other hand, immunoglobulin (Ig) E-mediated mechanisms and the protein tyrosine kinase signaling cascade are important in triggering the release of mediators from inflammatory cells. In spite of all of these, host regulatory mechanisms exist to limit the inflammation. An increase in the 3', 5'-cyclic adenosine monophosphate (cAMP) level generally suppresses the activities of immune and inflammatory cells, and the level of cAMP is closely regulated by a family of phosphodiesterases (PDEs). Heparin, a glycosaminoglycan released exclusively from mast cells, also is believed to possess anti-inflammatory actions. Many new therapeutic agents have been developed either to attenuate the pro-inflammatory processes in asthma or to augment the host anti-inflammatory mechanisms. In this article, we discuss the immunopharmacology of several of these agents, which include heparin and inhibitors of PDEs, tyrosine kinases, and NF-kappaB, as well as antibodies and soluble receptors directed against IgE, IL-4, and IL-5.

Heparin inhibits eicosanoid metabolism and hyperventilation-induced bronchoconstriction in dogs

Inhalation of heparin, an anticoagulant, attenuates exercise- induced asthma (EIA) in human subjects. The purpose of this study was to determine if heparin inhibits hyperventilation-induced bronchoconstriction (HIB) in a canine model of EIA, and if its mode of action involves the inhibition of eicosanoid mediator production and release. We used a wedged bronchoscope technique to measure baseline peripheral airway resistance (Rp). We then performed either a 2-min or 5-min dry air challenge (DAC) by temporarily increasing from 200 to 2,000 ml/min the flow of 5% CO(2) in air used to ventilate a wedged sublobar segment. We compared HIB before and 60 min after aerosol treatment with either bacteriostatic water (BW) or heparin. We found that (1) heparin had no effect on baseline Rp, (2) BW did not alter the response to DAC, and (3) heparin reduced HIB by approximately 50-60%. On the basis of bronchoalveolar lavage fluid (BALF) cell analysis, heparin and BW caused acute infiltration of macrophages and eosinophils, and heparin increased the number of erythrocytes recovered immediately after DAC. Despite these acute inflammatory effects initiated prior to DAC, BALF mediator analyses revealed that pretreatment with heparin either attenuated or abolished hyperventilation-induced leukotriene, prostaglandin, and thromboxane release. Thus, our data provide direct evidence that inhaled heparin inhibits eicosanoid mediator production and release caused by hyperventilation with dry air, and significantly attenuates HIB.

Inhibition of allergic late airway responses by inhaled heparin-derived oligosaccharides

Inhaled heparin has been shown to inhibit allergic bronchoconstriction in sheep that develop only acute responses to antigen (acute responders) but was ineffective in sheep that develop both acute and late airway responses (LAR) (dual responders). Because the antiallergic activity of heparin is molecular-weight dependent, we hypothesized that heparin-derived oligosaccharides (<2, 500) with potential anti-inflammatory activity may attenuate the LAR in the dual-responder sheep. Specific lung resistance was measured in 24 dual-responder sheep before and serially for 8 h after challenge with Ascaris suum antigen for demonstration of early airway response (EAR) and LAR, without and after treatment with inhaled medium-, low-, and ultralow-molecular-weight (ULMW) heparins and "non-anticoagulant" fractions (NAF) of heparin. Airway responsiveness was estimated before and 24 h postantigen as the cumulative provocating dose of carbachol that increased specific lung resistance by 400%. Only ULMW heparins caused a dose-dependent inhibition of antigen-induced EAR and LAR and postantigen airway hyperresponsiveness (AHR), whereas low- and medium-molecular-weight heparins were ineffective. The effects of ULMW heparin and ULMW NAF-heparin were comparable and inhibited the LAR and AHR even when administered "after" the antigen challenge. The ULMW NAF-heparin failed to inhibit the bronchoconstrictor response to histamine, carbachol, and leukotriene D(4), excluding a direct effect on airway smooth muscle. In six sheep, segmental antigen challenge caused a marked increase in bronchoalveolar lavage histamine, which was not prevented by inhaled ULMW NAF-heparin. The results of this study in the dual-responder sheep demonstrate that 1) the antiallergic activity of inhaled "fractionated" heparins is molecular-weight dependent, 2) only ULMW heparins inhibit the antigen-induced EAR and LAR and postantigen AHR, and 3) the antiallergic activity is mediated by nonanticoagulant fractions and resides in the ULMW chains of <2,500.

Lung deposition and clearance of inhaled (99m)Tc-heparin in healthy volunteers

The purpose of this study was to quantify the lower respiratory tract (LRT) dose delivered by a single nebulization of (99m)technetium-labeled sodium heparin as well as its airway distribution, and kinetics of aerosol clearance, since inhaled heparin may be useful in the treatment of asthma. Fifteen healthy subjects (5 male, 10 female) inhaled heparin from a jet nebulizer loaded with 90,000 IU of (99m)Tc-heparin, driving flow rate 10 L/min. Lung scintigrams and blood samples were taken immediately and at several time points up to 24 h after inhalation. 15 +/- 3% (mean +/- SD) (mean 13,300 IU) of the heparin nebulizer charge reached the mouth, and 8 +/- 2% (mean 7,000 IU) was found in the LRT. Jet nebulizer residual was 48 +/- 6% (mean 43,000 IU), 32 +/- 4% (mean 29,000) was found on exhalation filters, and 5 +/- 2% in the tubing. (99m)Tc-heparin was distributed uniformly in the lungs, and clearance was biphasic. 39 +/- 8% of the LRT dose of (99m)Tc-heparin remained in the lungs 24 h after inhalation. 10.00 +/- 3.40% (687 +/- 310 IU) of the LRT dose or 0.76 +/- 0.35% of the nebulizer charge was found in the blood. Peak concentration in the blood was found 61 +/- 25 min after conclusion of inhalation, which took 15 min. We conclude that a small but significant fraction of nebulized heparin reaches the LRT. The inhaled heparin distributes uniformly in the lungs from which it clears slowly, making it suitable for local administration without induction of measurable changes in coagulation assays. Administration of the present single dose of heparin thus appears to be safe.

Prevention of exercise-induced bronchoconstriction by inhaled low-molecular-weight heparin

Because many biological actions of heparin including the antiallergic activity are molecular weight dependent, we hypothesized that low-molecular-weight heparin (LMWH) may have greater potency in attenuating exercise-induced bronchoconstriction (EIB). Therefore, in the present investigation we studied the effects of inhaled LMWH, enoxaparin, and unfractionated heparin on EIB in subjects with asthma. Thirteen asthmatic subjects performed a standardized exercise challenge on a treadmill to document the presence of EIB. The workload was increased until 85% of predicted maximal heart rate was achieved, and the exercise was sustained at that workload for 10 min. EIB was assessed by measuring FEV(1) before and immediately after the exercise. On five different experiment days the subjects were pretreated with 4 ml of aerosolized heparin (80,000 units = 7.5 mg/kg), placebo, or 3 different doses of enoxaparin (0.5 mg/kg, 1 mg/kg, 2 mg/kg) in a double-blind, randomized, crossover design, and exercise challenge was performed 45 min later. Bronchial provocation with methacholine was also performed in five subjects on two additional days after pretreatment with either placebo or inhaled enoxaparin (2 mg/kg), and venous blood was obtained for analysis of plasma antifactor Xa. Postexercise, the maximal decreases in FEV(1) (mean +/- SE) were 30 +/- 4% and 29 +/- 5% on control and placebo days. The exercise-induced decreases in FEV(1) were inhibited by 31% with heparin (DeltaFEV(1) = 20 +/- 4%); and by 28%, 38%, and 48% by enoxaparin at doses of 0.5 mg/kg (DeltaFEV(1) = 21 +/- 5%), 1 mg/kg (DeltaFEV(1) = 18 +/- 5%), and 2 mg/kg (DeltaFEV(1) = 15 +/- 3%), respectively (p < 0.05). The inhibitory effect of 0.5 mg/kg dose of enoxaparin was comparable to heparin (7.5 mg/kg), whereas 2 mg/ kg dose of enoxaparin was the most potent. Inhaled enoxaparin failed to modify the bronchoconstrictor response to methacholine, and did not change the plasma antifactor Xa activity. These data demonstrate that inhaled enoxaparin prevents EIB in a dose-dependent manner; and its antiasthmatic activity is independent of its effect on plasma antifactor Xa activity.

Characterization of heparin aerosols generated in jet and ultrasonic nebulizers

Inhaled heparin has been used for asthma treatment, but results have been inconsistent, probably due to highly varying lung doses. We determined the output per unit time and the particle size distributions of sodium heparin, calcium heparin, and low molecular weight (LMW) heparin formulations in five concentrations from Sidestream jet nebulizers (Medic-Aid, Bognor Regis, England) and an Ultraneb 2000 ultrasonic nebulizer (DeVilbiss, Langen, Germany). We also determined the inhaled mass and the estimated respirable mass for some combinations. For the jet nebulizer, output per minute increased with increasing concentration and flow rate, and particle size decreased from 3.64 to 2.01 microns (mass median diameter [MMD]). The percentage of particles less than 3 microns ranged from 41% to 74%. For the ultrasonic nebulizer, maximum output per minute was achieved at a concentration of 7000 i.u./mL; this maximum depended upon the viscosity and temperature of the solution. MMD was independent of formulation, temperature, or concentration and ranged from 5.61 to 7.03 microns. Sodium heparin/calcium heparin in a concentration of 20,000 i.u./mL in the jet nebulizer driven at 10 L/min produced the highest dose of heparin capable of reaching the lower respiratory tract. Mass balance was determined for these combinations with the jet nebulizer run until visible aerosol generation ceased. Of a loading dose of 80,000 i.u. of heparin, 45,000 i.u. remained in the dead space of the nebulizer, 20,000 i.u. was deposited on the exhalation filter, and 15,000 i.u. was captured on the inhalation filter (inhaled mass). This corresponds to a respirable mass of 10,000 i.u. of heparin with a high probability of reaching the lower respiratory tract in normal healthy adults.

Heparin in inflammation: potential therapeutic applications beyond anticoagulation

In this chapter we have described anti-inflammatory functions of heparin distinct from its traditional anticoagulant activity. We have presented in vivo data showing heparin's beneficial effects in various preclinical models of inflammatory disease as well as discussed some clinical studies showing that the anti-inflammatory activities of heparin may translate into therapeutic uses. In vivo models that use low-anticoagulant heparins indicate that the anticoagulant activity can be distinguished from heparin's anti-inflammatory properties. In certain cases such as hypovolemic shock, the efficacy of a low-anticoagulant heparin derivative (GM1892) exceeds heparin. Data also suggest that nonconventional delivery of heparin, specifically via inhalation, has therapeutic potential in improving drug pharmacokinetics (as determined by measuring blood coagulation parameters) and in reducing the persistent concerns of systemic hemorrhagic complications. Results from larger clinical trials with heparin and LMW heparins are eagerly anticipated and will allow us to assess our predictions on the effectiveness of this drug class to treat a variety of human inflammatory diseases.

Nonorthopaedic problems in the aquatic athlete

This article discusses a number of medical conditions that are common to aquatic athletes. Exercise-induced asthma is particularly prevalent in swimmers because swimming is among the activities tolerated best by asthmatics. The healthcare professional frequently must evaluate and manage respiratory infections and infectious mononucleosis in swimmers, particularly in regard to the safe timing of return to training and competition. Dilutional sports pseudoanemia must be differentiated from the true anemias that are due mostly to iron-deficiency and intravascular hemolysis. Finally, the evaluation, management, and prevention of otitis externa, external auditory canal exostoses, and dermatologic disorders in swimmers are reviewed.

Molecular-weight-dependent effects of nonanticoagulant heparins on allergic airway responses

We have hypothesized that antiallergic activity of inhaled heparin is molecular weight dependent and mediated by "nonanticoagulant fractions" (NAF-heparin). Therefore, we studied comparative effects of high-, medium-, and ultralow-molecular-weight (HMW, MMW, and ULMW, respectively) NAF-heparins on acute bronchoconstrictor response (ABR) and airway hyperresponsiveness (AHR) in allergic sheep. Specific lung resistance was measured in 23 allergic sheep, before and immediately after challenge with Ascaris suum antigen, without and after pretreatment with inhaled NAF-heparins. Airway responsiveness was estimated before and 2 h postantigen as the cumulative provocating dose of carbachol in breath units, which increased specific lung resistance by 400%. NAF-heparins attenuated ABR and AHR in a molecular-weight-dependent fashion. HMW NAF-heparin (n = 8) was the least effective agent: it attenuated ABR [inhibitory dose causing 50% protection (ID50) = 4 mg/kg] but had no effect on AHR. MMW NAF-heparin (n = 8) showed intermediate efficacy (ABR ID50 = 0.8 mg/kg, AHR ID50 = 1.4 mg/kg), whereas ULMW NAF-heparin (n = 7) was the most effective agent (ABR ID50 = 0.4 mg/kg, AHR ID50 = 0.2 mg/kg). ULMW NAF-heparin was 3.5 times more potent in attenuating antigen-induced AHR when administered "after" antigen challenge and failed to inhibit the bronchoconstrictor response to carbachol and histamine. In 15 additional sheep, segmental antigen challenge caused a marked increase in histamine in bronchoalveolar lavage fluid that was not prevented by any of the inhaled NAF-heparins. These data indicate that antiallergic activity of inhaled heparin is independent of its anticoagulant action and resides in the <2,500 ULMW chains. The antiallergic activity of NAF-heparins is mediated by an unknown biological action and may have therapeutic potential.