Gene polymorphisms involved in triptans pharmacokinetics and pharmacodynamics in migraine therapy.

IMPORTANCE OF THE FIELD: Migraine is a debilitating and painful neurological disorder affecting millions of people worldwide and often worsened by chronification. Triptans represent a powerful pharmacological resource in migraine management; nevertheless, a significant portion of treated patients do not obtain consistent pain relief through triptans. Pharmacogenomics may offer a new way to rationalise triptans administration, based on characterisation of the individual genomic profile. AREAS COVERED IN THIS REVIEW: The review summarises the results of association studies between polymorphisms in genes involved in the kinetics and dynamics of triptans, and clinical response to them in migraineurs. WHAT THE READER WILL GAIN: A summary of data available at present from genetic studies in the field of triptan therapy in migraine, and a picture of the difficulties facing research into the pharmacogenomics of triptans. TAKE HOME MESSAGE: Pharmacogenomic studies of triptans suggest that some genetic determinants influence drug response, but the complexity of the field calls for application of a systematic approach to genetic association studies, allowing identification of a therapy response prediction panel with adequate predictive power.

Genetic polymorphisms related to efficacy and overuse of triptans in chronic migraine.

Migraine is a common type of headache and its most severe attacks are usually treated with triptans, the efficacy of which is extremely variable. Several SNPs in genes involved in metabolism and target mechanisms of triptans have been described. To define an association between genetic profile and triptan response, we classified a migrainous population on the basis of triptan response and characterized it for polymorphisms in the genes coding for monoamine oxidase A, G protein ß3 and the cytochrome CYP1A2. Analysis of the association between genotypic and allelic frequencies of the analyzed SNPs and the grade of response to triptan administration showed a significant correlation for MAOA uVNTR polymorphism. Further stratification of patients in abuser and non-abuser groups revealed a significant association with triptan overuse and, within the abusers, with drug response to the CYP1A2*1F variant.

Frequencies of genetic polymorphisms related to triptans metabolism in chronic migraine.

Chronic migraine (CM) prevalence ranges around 1-5%. Most of these patients usually treat their acute attacks with triptans, whose efficacy is extremely variable. A genetic basis for migraine is evident and many susceptibility genes have been described, as well as gene polymorphisms possibly implied in therapy response. Several factors could be involved in the evolution of episodic migraine into a chronic form, such as natural history, psychiatric comorbidity, and the individual's response to therapy. During a study aimed at detecting connections between genotype and response to triptans administration, we characterized a CM population for polymorphisms in the genes coding for monoamine oxidase A, g-protein beta 3 and the cytochromes CYP3A4 and CYP1A2. Alleles and genotypes distributions were compared with known frequencies of healthy Caucasian populations. A significant association with CM was found for the long allele of monoamine oxidase A 30 bp VNTR and CYP1A2*1F variant. Such genomic analysis is part of an integrated platform able to evaluate different levels of metabolic pathways of drugs in CM and their influence in the chronicization process.

Future drugs for migraine.

Migraine is a complex, neurovascular disorder in which genetic and environmental factors interact. At present, frontline therapies in the acute treatment of migraine include the use of non-steroidal anti-inflammatory drugs and triptans. Evidence indicates that calcitonin gene-related peptide (CGRP) plays a fundamental role in the mechanism of migraine. CGRP is a strong vasodilatatory neuropeptide that is released from activated trigeminal sensory nerves. The development of CGRP antagonists has also been driven by the fact that triptans are vasoconstrictive and cannot be safely used in patients with cardiovascular risk factors. Olcegepant (BIBN4096) is the first CGRP antagonist for the treatment of migraine that has been tested in clinical trials, but because of its poor oral bioavailability, only the intravenous formulation has been tested. The first oral non-peptide CGRP antagonist, telcagepant, has been shown recently to be highly effective in the treatment of migraine attacks. This development can be considered as the most important pharmacological breakthrough for migraine treatment since the introduction of sumatriptan in the early 1990s. These results are also of importance, since they support an interesting pathophysiological hypothesis of migraine. The pipeline of future compounds for the treatment of acute migraine headaches include TPRV1 antagonists, prostaglandin E receptor 4 (EP(4)) receptor antagonists, serotonin 5HT1(F) receptor agonists and nitric oxide synthase inhibitors. The immediate future of a preventative treatment for migraine headaches is well represented by botulinum toxin type-A, glutamate NMDA receptor antagonists, gap-junction blocker tonabersat and an angiotensin type 1 blocker candesartan.

Proinflammatory mediators and migraine pathogenesis: moving towards CGRP as a target for a novel therapeutic class.

Migraine is a complex neurological disorder in which genetic and environmental factors interact. At present, frontline therapies in migraine's acute treatment include the use of NSAIDS and triptans. Restrictions in the use of frontline drugs for migraine treatment and evidence concerning CGRP's key role led research towards new pathways involved in migraine pathophysiology. CGRP is a strong vasodilatory neuropeptide released from activated trigeminal sensory nerves. The development of CGRP antagonists has also been driven by the fact that triptans are vasoconstrictive and cannot be used in patients with vascular risk factors. BIBN4096 (olcegepant) is the first CGRP antagonist for the treatment of migraine which has been tested in clinical trials, but its principal limitation is that BIBN4096 presents low oral bioavailability and has only been tested through intravenous formulation. The first oral nonpeptide CGRP antagonist, MK-0974 (telcagepant), has recently been shown to be highly effective in the treatment of migraine attacks. This development can be considered the most important pharmacological breakthrough for migraine treatment since the introduction of sumatriptan in the early 1990s. These results are important since they confirm the current pathophysiological concept of migraine. The future introduction of CGRP antagonists in clinical practice could represent a progress for migraine therapy.

The Italian Diabetes and Exercise Study (IDES): design and methods for a prospective Italian multicentre trial of intensive lifestyle intervention in people with type 2 diabetes and the metabolic syndrome.

BACKGROUND AND AIMS: The IDES is a prospective Italian multicentre randomized controlled trial to evaluate the efficacy of an intensive lifestyle intervention on modifiable cardiovascular disease (CVD) risk factors in a large cohort of people with type 2 diabetes and the metabolic syndrome. METHODS AND RESULTS: We recruited 606 subjects with type 2 diabetes and waist circumference >94 cm (M) and >80 cm (F), plus >1 other metabolic syndrome trait (IDF criteria) for both sexes, aged 40-75 years, BMI 27-40 kg/m(2), diabetes duration >1 year with a sedentary lifestyle of >6 months. Patients were randomized into two groups: a control group, receiving conventional care including exercise counselling and an intervention group, treated with a mixed (aerobic and resistance) exercise programme (150 min/week) prescribed and supervised for 12 months. Primary outcome is HbA1c reduction. Secondary outcomes include other traditional and non-traditional risk factors and their relationship to exercise volume/intensity and fitness; dosage of glucose, lipid and blood pressure-lowering drugs; global CVD 10-year risk; patient well-being; and costs. CONCLUSION: This trial verifies whether a prescribed and supervised exercise programme, including both aerobic and resistance training, is more effective than conventional exercise counselling in reducing modifiable CVD risk factors in type 2 diabetic subjects with the metabolic syndrome.

Role of galectin-3 in diabetic nephropathy.

The advanced glycosylation end products (AGE) participate in the pathogenesis of nephropathy and other diabetic complications through several mechanisms, including their binding to cell surface receptors. The AGE receptors include RAGE, the macrophage scavenger receptors, OST-48 (AGE-R1), 80K-H (AGE-R2), and galectin-3 (AGE-R3). Galectin-3 interacts with the beta-galactoside residues of cell surface and matrix glycoproteins via the carbohydrate recognition domain and with intracellular proteins via peptide-peptide associations mediated by its N-terminus domain. These structural properties enable galectin-3 to exert multiple functions, including the mRNA splicing activity, the control of cell cycle, the regulation of cell adhesion, the modulation of allergic reactions, and the binding of AGE. The lack of transmembrane anchor sequence or signal peptide suggests that it is associated with other AGE receptors, possibly AGE-R1 and AGE-R2, to form an AGE-receptor complex, rather than playing an independent role. In target tissues of diabetic vascular complications, such as the endothelium and mesangium, galectin-3 is weakly expressed under basal conditions and is markedly upregulated by the diabetic milieu (and to a lesser extent by aging). Galectin-3-deficient mice were found to develop accelerated diabetic glomerulopathy versus the wild-type animals, as evidenced by the more pronounced increase in proteinuria, mesangial expansion, and matrix gene expression. This was associated with a more marked renal/glomerular AGE accumulation, suggesting that it was attributable to the lack of galectin-3 AGE-receptor function. These data indicate that galectin-3 is upregulated under diabetic conditions and is operating in vivo to provide protection toward AGE-induced tissue injury, as opposed to RAGE.