Nerve ablation after bronchial thermoplasty and sustained improvement in severe asthma

BACKGROUND

Bronchial thermoplasty (BT) is a non-pharmacological intervention for severe asthma whose mechanism of action is not completely explained by a reduction of airway smooth muscle (ASM). In this study we analyzed the effect of BT on nerve fibers and inflammatory components in the bronchial mucosa at 1 year.

METHODS

Endobronchial biopsies were obtained from 12 subjects (mean age 47 ± 11.3 years, 50% male) with severe asthma. Biopsies were performed at baseline (T0) and after 1 (T1), 2 (T2) and 12 (T12) months post-BT, and studied with immunocytochemistry and microscopy methods. Clinical data including Asthma Quality of Life Questionnaire (AQLQ) and Asthma Control Questionnaire (ACQ) scores, exacerbations, hospitalizations, oral corticosteroids use were also collected at the same time points.

RESULTS

A statistically significant reduction at T1, T2 and T12 of nerve fibers was observed in the submucosa and in ASM compared to T0. Among inflammatory cells, only CD68 showed significant changes at all time points. Improvement of all clinical outcomes was documented and persisted at the end of follow up.

CONCLUSIONS

A reduction of nerve fibers in epithelium and in ASM occurs earlier and persists at one year after BT. We propose that nerve ablation may contribute to mediate the beneficial effects of BT in severe asthma.

TRIAL REGISTRATION

Registered on April 2, 2013 at ClinicalTrials.gov Identifier: NCT01839591 .

Toll-like receptor 4 (TLR4) gene polymorphisms in giant cell arteritis

OBJECTIVE

To investigate potential associations between toll-like receptor 4 (TLR4) gene polymorphisms and susceptibility to, and clinical features of giant cell arteritis (GCA).

METHODS

A total of 155 patients with biopsy-proven GCA who were residents of Reggio Emilia, Italy, and 210 population-based controls from the same geographical area were genotyped for two coding single nucleotide polymorphisms of TLR4 (Asp299Gly and Thr399Ile) by molecular methods. The patients were subgrouped according to the presence or absence of polymyalgia rheumatica and severe ischemic complications (visual loss and/or cerebrovascular accidents).

RESULTS

The distribution of allele and genotype frequencies did not differ significantly between GCA patients and healthy controls. Carriers of the -299 G allele (G/A+ G/G) [odds ratio (OR) 1.78, 95% confidence intervals (CI) 0.90-3.50)] were more frequent among GCA patients than among the controls, but the difference was not statistically significant. No significant associations were found when GCA patients with and without PMR or with and without severe ischemic complications were compared.

CONCLUSION

Our data suggest that the TLR4 gene polymorphisms are not associated with susceptibility to, and clinical expression of, GCA in Italian patients.

1T magnetic resonance imaging in the diagnosis of giant cell arteritis: comparison with ultrasonography and physical examination of temporal arteries

OBJECTIVE

To assess the usefulness of 1T magnetic resonance imaging (MRI) of temporal arteries and to compare 1T MRI with duplex ultrasonography (US) and physical examination of temporal arteries for the diagnosis of giant cell arteritis (GCA) in patients with suspected GCA.

METHOD

The superficial temporal arteries of 20 consecutive patients with a suspected diagnosis of GCA were examined using a 1T MRI scanner. Fat-saturated multislice T1-weighted spin-echo images were acquired perpendicularly to the orientation of the vessel. In all cases, MRI results were compared to US and temporal artery examination findings. Temporal artery biopsies were performed in all patients.

RESULTS

Mural contrast enhancement of the temporal arteries on MRI had a sensitivity of only 33.3% and a specificity of 87.5% for the diagnosis of biopsy-proven GCA. Compared with the diagnosis of GCA by the American College of Rheumatology criteria, MRI had a sensitivity and specificity of 27.2% and 88.9%, respectively. Temporal artery abnormalities on physical examination and the presence of a hypoechoic halo on US had a higher sensitivity (66.7% and 77.7%, respectively) and a higher specificity (100% for both) compared to MRI findings.

CONCLUSION

1T MRI is not useful for the diagnosis of GCA because of its low sensitivity. US and physical examination of temporal arteries had a better diagnostic accuracy. However, our data does not exclude a diagnostic role for higher-resolution MRI.

-463 G/A myeloperoxidase promoter polymorphism in giant cell arteritis

OBJECTIVE

To investigate potential associations between-463 G/A myeloperoxidase (MPO) promoter polymorphism and susceptibility to, and clinical features of giant cell arteritis (GCA).

METHODS

A total of 156 patients with biopsy-proven GCA who were residents of Reggio Emilia, Italy, and 235 population-based controls from the same geographic area were genotyped for-463 G/A promoter polymorphism of the MPO gene by molecular methods. The patients were subgrouped according to the presence or absence of polymyalgia rheumatica and severe ischaemic complications (visual loss and/or cerebrovascular accidents).

RESULTS

The distribution of the MPO-G/A genotype differed significantly between patients with GCA and the controls (p(corr) = 0.003). Allele G was significantly more frequent in patients with GCA than in the controls (p(corr) = 0.0002, OR 2.0, 95% CI 1.4 to 2.9). Homozygosity for the G allele was significantly more frequent in patients with GCA than in controls (p(corr) = 0.0002, OR 2.2, 95% CI 1.4 to 3.4). No significant associations were found when patients with GCA with and without polymyalgia rheumatica or with and without severe ischaemic complications were compared.

CONCLUSIONS

Our findings show that the-463 G/A promoter polymorphism of the MPO gene is associated with GCA susceptibility and support a role for MPO in the pathophysiology of GCA.