The mechanisms of aspirin-intolerant asthma and its management

Asthma remission one, none and one-hundred thousand: the relevance of the patient's view

OBJECTIVE

Achieving remission in severe asthma holds paramount importance in elevating patient quality of life and reducing both individual and societal burdens associated with this chronic condition. This study centers on identifying pivotal patient-relevant endpoints through standardized, reproducible methods, while also developing a patient-centric definition of remission, essential for effective disease management.

METHODS

A discrete choice experiment (DCE) was conducted to assess patients' perceptions on the four primary criteria for defining severe asthma remission, as outlined by the SANI survey. Additionally, it investigated the correlation between these perceptions and improvements in the doctor-patient therapeutic alliance during treatment decision-making.

RESULTS

249 patients (70% aged between 31-60, 59% women and 82% without other pathologies requiring corticosteroids) prioritize the use of oral corticosteroids (OCS, 48%) and the Asthma Control Test (ACT, 27%) in defining their condition, ranking these above lung function and exacerbations. This preference for OCS stems from its direct role in treatment, tangible tracking, immediate symptom relief, and being a concrete measure of disease severity compared to the less predictable and quantifiable exacerbations.

CONCLUSIONS

This study explores severe asthma remission from patients' perspectives using clinician-evaluated parameters. The DCE revealed that most patients highly value OCS and the ACT, prefer moderate improvement, and avoid cortisone cycles. No definitive preference was found for lung function status. Integrating patient-reported information with professional insights is crucial for effective management and future research. Personalized treatment plans focusing on patient preferences, adherence, and alternative therapies aim to achieve remission and enhance quality of life.

Structures of Leukotriene Biosynthetic Enzymes and Development of New Therapeutics

Leukotrienes are potent immune-regulating lipid mediators with patho-genic roles in inflammatory and allergic diseases, particularly asthma. These autacoids also contribute to low-grade inflammation, a hallmark of cardiovascular, neurodegenerative, metabolic, and tumor diseases. Biosynthesis of leukotrienes involves release and oxidative metabolism of arachidonic acid and proceeds via a set of cytosolic and integral membrane enzymes that are typically expressed by cells of the innate immune system. In activated cells, these enzymes traffic and assemble at the endoplasmic and perinuclear membrane, together comprising a biosynthetic complex. Here we describe recent advances in our molecular understanding of the protein components of the leukotriene-synthesizing enzyme machinery and also briefly touch upon the leukotriene receptors. Moreover, we discuss emerging opportunities for pharmacological intervention and development of new therapeutics.

Integral Membrane Enzymes in Eicosanoid Metabolism: Structures, Mechanisms and Inhibitor Design

Eicosanoids are potent lipid mediators involved in central physiological processes such as hemostasis, renal function and parturition. When formed in excess, eicosanoids become critical players in a range of pathological conditions, in particular pain, fever, arthritis, asthma, cardiovascular disease and cancer. Eicosanoids are generated via oxidative metabolism of arachidonic acid along the cyclooxygenase (COX) and lipoxygenase (LOX) pathways. Specific lipid species are formed downstream of COX and LOX by specialized synthases, some of which reside on the nuclear and endoplasmic reticulum, including mPGES-1, FLAP, LTC4 synthase, and MGST2. These integral membrane proteins are members of the family "membrane-associated proteins in eicosanoid and glutathione metabolism" (MAPEG). Here we focus on this enzyme family, which encompasses six human members typically catalyzing glutathione dependent transformations of lipophilic substrates. Enzymes of this family have evolved to combat the topographical challenge and unfavorable energetics of bringing together two chemically different substrates, from cytosol and lipid bilayer, for catalysis within a membrane environment. Thus, structural understanding of these enzymes are of utmost importance to unravel their molecular mechanisms, mode of substrate entry and product release, in order to facilitate novel drug design against severe human diseases.

Aspirin sensitivity and the nose

There is a well-recognized association of aspirin sensitivity, aspirin-induced asthma, nasal polyposis or sinusitis, known as Samter's triad. This article outlines the pathogenesis and clinical features of this condition and reviews current management options.

Medical and surgical considerations in patients with Samter's triad

BACKGROUND

The aim of this study was to report on objective and subjective outcomes of patients with Samter's triad (ST) treated with functional endoscopic sinus surgery (FESS), and correlate these results with aspirin desensitization (DS) in patients.

METHODS

We performed a retrospective analysis of prospectively collected data in 15 patients requiring revision FESS after failing maximum medical therapy and prior sinus surgery for chronic rhinosinusitis in the context of ST. Five patients underwent aspirin DS and 10 patients did not (non-DS). These patients represent a subset of patients previously reported who were treated in a tertiary rhinology setting over a 3-year period (1999-2001). CT scans were graded according to the Lund-Mackay grading scale and symptom scores were assessed using the Sino-Nasal Outcome Test (SNOT-20). Endoscopy was scored according to the Rhinosinusitis Task Force methodology. All patients had a minimum 2-year follow-up.

RESULTS

Preoperative CT scores were 20.1+/-1.9 for non-DS patients and 20.4+/-2.0 for DS patients (p = NS). Preoperative and postoperative SNOT-20 scores for non-DS patients were 31.8+/-3.9 and 8.8+/-1.7, respectively, as compared with 32.0 z 3.6 and 7.3 +/-1.7 for DS patients (p = NS). Preoperative and postoperative endoscopy scores for non-DS patients were 7.6+/-1.2 and 2.0+/-0.4, respectively, as compared with 7.6 +/-1.3 and 1.1+/-0.4 for DS patients (p = NS). Of DS patients, none required additional surgery whereas 8 of 10 non-DS patients required additional revision during the follow-up period (p = 0.003).

CONCLUSION

Revision FESS benefits patients with ST; however, the addition of aspirin DS decreases the likelihood that patients with ST will require additional surgical intervention over a 2-year period.

Severe asthma treatment: need for characterising patients

CONTEXT

Asthma is readily diagnosed in most cases and usually responds to inhaled corticosteroids with or without long-acting beta agonists, theophyllines, or leukotriene-receptor antagonists, adjusted stepwise according to symptoms and lung function. However, up to 40% of adult patients with asthma remain symptomatic, and up to 5% have difficult-to-control asthma despite multiple therapies. It is suggested that higher doses of inhaled steroids with long-acting beta2 agonists should be used for total control of symptoms; and anti-IgE therapy is newly licensed in the USA. However, difficult-to-control asthma is complex and multifactorial, and is often not due to severe or therapy-resistant asthma.

STARTING POINT

Last year saw encouraging reports on omalizumab (anti-IgE therapy) in severe allergic asthma, by Stephen Holgate, Jon Ayres, and their respective colleagues (Clin Exp Allergy 2004; 34: 632-38; Allergy 2004; 59: 701-08). Omalizumab reduced exacerbation rates, improved asthma symptoms and quality of life, and allowed lower doses of inhaled steroid compared with placebo. In placebo-controlled studies with anti-IgE, many patients were able to substantially reduce and even withdraw inhaled steroids in the placebo arm.

WHERE NEXT

Severe asthma is often defined as persisting symptoms despite high-dose inhaled steroids. This definition is likely to include patients with various reasons for their persisting symptoms, for whom additional treatment is not always required. Before starting new therapy, it is important to systematically evaluate asthmatic patients to accurately define their disease and to identify those whose symptoms are caused by other factors, and thus avoid unnecessary medication. There might also be subgroups that have differing underlying inflammatory processes and who will respond differently to individual treatments.

A benefit-risk assessment of agents used in the secondary prevention of stroke

Stroke is a major cause of morbidity and mortality. Full assessment of stroke or transient ischaemic attack (TIA) patients is required to identify all risk factors and apply appropriate secondary preventative strategies. Antiplatelet therapies are effective in the secondary prevention of ischaemic stroke and can be justified despite adverse effects such as gastrointestinal haemorrhage. Aspirin (acetylsalicylic acid), aspirin plus dipyridamole, ticlopidine and clopidogrel are all of value but their adverse effect profiles vary significantly. Combinations of antiplatelet agents may offer additional benefit but not all combinations have been studied in stroke patients. Anticoagulation with agents such as warfarin is effective with coexisting atrial fibrillation and other conditions predisposing to cardioembolic stroke. Antihypertensive agents have been extensively studied in the primary prevention of stroke; however, relatively few trials of antihypertensive agents in the secondary prevention of stroke are available. The incidence of adverse effects of antihypertensive agents is relatively low and the benefit-risk profile would tend to favour their use in the secondary prevention of stroke. Recent studies of ACE inhibitors have identified an important role for these agents in the secondary prevention of stroke even in those who are normotensive and in those who have had a haemorrhagic stroke. The incidence of serious adverse effects with ACE inhibitors appears relatively low. Lipid-lowering agents may have a role to play in certain groups of patients with stroke. The incidence of adverse effects is relatively low with HMG-CoA reductase inhibitors. Cigarette smoking is an important risk factor for stroke and evidence is available that smoking cessation does reduce the individual's risk of stroke. Pharmacological agents are available to help smoking cessation. In patients with diabetes mellitus, intensive regimens with insulin and oral hypoglycaemic agents have so far not definitively been shown to reduce the incidence of macrovascular complications such as stroke. Tight glycaemic control has been shown to improve microvascular complications such as retinopathy, nephropathy and neuropathy and hence this is reason enough to advocate the use of these agents. Future developments in the treatment of diabetes may help. Secondary prevention of stroke has improved greatly over the past decade and hopefully will continue to improve. The use of pharmacological agents available currently and in the future will be clarified and refined as further clinical trials report.