Contractile properties of isolated vascular smooth muscle after photoradiation

Beclomethasone dipropionate and formoterol fumarate synergistically interact in hyperresponsive medium bronchi and small airways

Background

Corticosteroids increase the expression of β₂-adrenoceptors (β₂-ARs) and protect them against down-regulation. Conversely, β₂-AR agonists improve the anti-inflammatory action of corticosteroids. Nevertheless, it is still uncertain whether adding a long-acting β₂-AR agonist (LABA) to an inhaled corticosteroid (ICS) results in an additive effect, or there is true synergy.

Therefore, the aim of this study was to pharmacologically characterize the interaction between the ICS beclomethasone diproprionate (BDP) and the LABA formoterol fumarate (FF) in a validated human ex vivo model of bronchial asthma.

Methods

Human medium and small airways were stimulated by histamine and treated with different concentrations of BDP and FF, administered alone and in combination at concentration-ratio reproducing ex vivo that of the currently available fixed-dose combination (FDC; BDP/FF 100:6 combination-ratio). Experiments were performed in non-sensitized (NS) and passively sensitized (PS) airways. The pharmacological interaction was assessed by using Bliss Independence and Unified Theory equations.

Results

BDP/FF synergistically increased the overall bronchorelaxation in NS and PS airways (+ 15.15% ± 4.02%; P < 0.05 vs. additive effect). At low-to-medium concentrations the synergistic interaction was greater in PS than in NS bronchioles (+ 16.68% ± 3.02% and + 7.27% ± 3.05%, respectively). In PS small airways a very strong synergistic interaction (Combination Index: 0.08; + 20.04% ± 2.18% vs. additive effect) was detected for the total concentrations of BDP/FF combination corresponding to 10.6 ng/ml.

Conclusion

BDP/FF combination synergistically relaxed human bronchi; the extent of such an interaction was very strong at low-to-medium concentrations in PS small airways.

Trial registration

Not applicable.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0770-7) contains supplementary material, which is available to authorized users.

Epithelium integrity is crucial for the relaxant activity of brain natriuretic peptide in human isolated bronchi

BACKGROUND AND PURPOSE Brain natriuretic peptide (BNP) plays an important role in several biological functions, including bronchial relaxation. Here, we have investigated the role of BNP and its cognate receptors in human bronchial tone. EXPERIMENTAL APPROACH Effects of BNP on responses to carbachol and histamine were evaluated in non-sensitized, passively sensitized, epithelium-intact or denuded isolated bronchi and in the presence of methoctramine, N(ω) -nitro-L-arginine methyl ester (L-NAME) and aminoguanidine. Natriuretic peptide receptors (NPRs) were investigated by immunohistochemistry, RT-PCR and real-time PCR. Release of NO and acetylcholine from bronchial tissues and cultured BEAS-2B bronchial epithelial cells was also investigated. KEY RESULTS BNP reduced contractions mediated by carbachol and histamine, with decreased E(max) (carbachol: 22.7 ± 4.7%; histamine: 59.3 ± 1.8%) and increased EC(50) (carbachol: control 3.33 ± 0.88 µM, BNP 100 ± 52.9 µM; histamine: control 16.7 ± 1.7 µM, BNP 90 ± 30.6 µM); BNP was ineffective in epithelium-denuded bronchi. Among NPRs, only atrial NPR (NPR1) transcripts were detected in bronchial tissue. Bronchial NPR1 immunoreactivity was detected in epithelium and inflammatory cells but faint or absent in airway smooth muscle cells. NPR1 transcripts in bronchi increased after incubation with BNP, but not after sensitization. Methoctramine and quinine abolished BNP-induced relaxant activity. The latter was associated with increased bronchial mRNA for NO synthase and NO release, inhibited by L-NAME and aminoguanidine. In vitro, BNP increased acetylcholine release from bronchial epithelial cells, whereas NO release was unchanged. CONCLUSIONS AND IMPLICATIONS Epithelial cells mediate the BNP-induced relaxant activity in human isolated bronchi.

Mesenchymal stromal cells for cardiovascular disease

The fields of regenerative medicine and cellular therapy have been the subject of tremendous hype and hope. In particular, the perceived usage of somatic cells like mesenchymal stromal cells (MSCs) has captured the imagination of many. MSCs are a rare population of cells found in multiple regions within the body that can be readily expanded ex vivo and utilized clinically. Originally, it was hypothesized that transplantation of MSCs to sites of injury would lead to de novo tissue-specific differentiation and thereby replace damaged tissue. Now, it is generally agreed that MSC home to sites of injury and direct positive remodeling via the secretion of paracrine factors. Consequently, their clinical utilization has largely revolved around their abilities to promote neovascularization for ischemic disorders and modulate overly exuberant inflammatory responses for autoimmune and alloimmune conditions. One of the major issues surrounding the development of somatic cell therapies like MSCs is that despite evoking a positive response, long-term engraftment and persistence of these cells is rare. Consequently, very large cell doses need be administered for raising production, delivery, and efficacy issues. In this review, we will outline the field of MSC in the context of ischemia and discuss causes for their lack of persistence. In addition, some of the methodologies be used to enhance their therapeutic potential will be highlighted.

Mesenchymal stem cell homing: the devil is in the details

The study of MSC trafficking is clinically relevant for minimally invasive cell therapy to promote regeneration of damaged tissue, to treat inflammation, and to promote angiogenesis. However, these studies are complicated by the diverse methods used to culture, characterize, and deliver MSCs and by the variety of methods used to assess homing events. This review provides a critical analysis of the methods used to track homing of exogenously infused MSCs and discusses strategies for enhancing their trafficking to particular tissues.