Roflumilast in the management of chronic obstructive pulmonary disease

Modulation of Human Dendritic Cell Functions by Phosphodiesterase-4 Inhibitors: Potential Relevance for the Treatment of Respiratory Diseases

Inhibitors of phosphodiesterase-4 (PDE4) are small-molecule drugs that, by increasing the intracellular levels of cAMP in immune cells, elicit a broad spectrum of anti-inflammatory effects. As such, PDE4 inhibitors are actively studied as therapeutic options in a variety of human diseases characterized by an underlying inflammatory pathogenesis. Dendritic cells (DCs) are checkpoints of the inflammatory and immune responses, being responsible for both activation and dampening depending on their activation status. This review shows evidence that PDE4 inhibitors modulate inflammatory DC activation by decreasing the secretion of inflammatory and Th1/Th17-polarizing cytokines, although preserving the expression of costimulatory molecules and the CD4+ T cell-activating potential. In addition, DCs activated in the presence of PDE4 inhibitors induce a preferential Th2 skewing of effector T cells, retain the secretion of Th2-attracting chemokines and increase the production of T cell regulatory mediators, such as IDO1, TSP-1, VEGF-A and Amphiregulin. Finally, PDE4 inhibitors selectively induce the expression of the surface molecule CD141/Thrombomodulin/BDCA-3. The result of such fine-tuning is immunomodulatory DCs that are distinct from those induced by classical anti-inflammatory drugs, such as corticosteroids. The possible implications for the treatment of respiratory disorders (such as COPD, asthma and COVID-19) by PDE4 inhibitors will be discussed.

Capsaicin suppresses ciliary function, while inducing permeability in bronchial epithelial cell cultures of COPD patients

Take Home Message: Capsaicin modified inflammatory response and caused toxicity in bronchial epithelial cultures from patients with COPD. More importantly, capsaicin decreased ciliary beat frequency and induced epithelial permeability and these effects were partially prevented by formoterol and roflumilast.

Tear gas is widely used to halt mass demonstrations. Studies have reported its adverse effects on multiple organ systems; however, its effect on individuals with chronic respiratory diseases and the underlying mechanisms of these effects are unclear. For the first time in the literature, we investigated the effects of capsaicin, the active ingredient of tear gas, on bronchial epithelial cell (BEC) cultures obtained from well-characterized groups of nonsmokers, smokers, and patients with chronic obstructive pulmonary disease (COPD). BEC cultures were incubated with 50-500 μM capsaicin in the absence and presence of formoterol (1μM) and roflumilast (0.1 μM) for 24 h. Ciliary beat frequency (CBF) and transepithelial electrical resistance (TEER) were assessed at T1/4, T1/2, T1, T2, T4, T6, and T24 h, whereas the release of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-8, and lactate dehydrogenase (LDH) was measured at T24 h. Capsaicin (250 µM) significantly decreased CBF of all BEC cultures from T1/4 h to T24 h (p<0.05). Formoterol significantly prevented decreases in CBF induced by capsaicin. Higher concentrations of capsaicin (250-500 μM) significantly reduced TEER of BECs from nonsmokers (T2-T24 h), smokers (T24 h) and COPD patients (T2 and T24 h), which was partially prevented by roflumilast. Capsaicin (500 μM) decreased release of IL-8 (p<0.0001) and GM-CSF (p<0.05) while inducing release of LDH in BECs (p<0.05), and this was more prominent in BEC from patients with COPD. In conclusion, our findings demonstrate that capsaicin can suppress ciliary activity and cytokine release from BECs, induce BEC culture permeability and cellular toxicity and that these effects can be partially prevented by formoterol and roflumilast.

Second-generation TNFα turnover model for improved analysis of test compound interventions in LPS challenge studies

This study presents a non-linear mixed effects model describing tumour necrosis factor alpha (TNFα) release after lipopolysaccharide (LPS) provocations in absence or presence of anti-inflammatory test compounds. Inter-occasion variability and the pharmacokinetics of two test compounds have been added to this second-generation model, and the goal is to produce a framework of how to model TNFα response in LPS challenge studies in vivo and demonstrate its general applicability regardless of occasion or type of test compound. Model improvements based on experimental data were successfully implemented and provided a robust model for TNFα response after LPS provocation, as well as reliable estimates of the median pharmacodynamic parameters. The two test compounds, Test Compound A and roflumilast, showed 81.1% and 74.9% partial reduction of TNFα response, respectively, and the potency of Test Compound A was estimated to 0.166 µmol/L. Comparing this study with previously published work reveals that our model leads to biologically reasonable output, handles complex data pooled from different studies, and highlights the importance of accurately distinguishing the stimulatory effect of LPS from the inhibitory effect of the test compound.

Early COPD: current evidence for diagnosis and management

Chronic obstructive pulmonary disease (COPD) affects one-tenth of the world's population and has been identified as a major global unmet health need by the World Health Organisation, which predicts that within 10 years, COPD will become the third leading cause of death. Despite active research, there have been no recent major strides in terms of disease modifying treatment for COPD; smoking cessation remains the only intervention known to alter disease progression and improve mortality. As established COPD is a key driver of disease burden, earlier diagnosis coupled with disease-modifying intervention carries promise as a route to address this global health priority. The concept of early COPD is emerging as an area of focus for research and consideration of new treatment modalities, as it has been hypothesised that intervention at this stage may potentially halt or reverse the disease process. However, at present, a globally accepted criteria for defining early COPD does not exist. Several studies propose small airways disease as the earliest stage in the development of COPD, and this has been demonstrated to be a precursor to development of emphysema and to correlate with subsequent development of airflow obstruction. However, treatment strategies for early disease, which pre-date the development of airflow obstruction, remain uncertain. This review addresses the rationale and current evidence base for the diagnosis and treatment of early COPD and highlights the challenges of implementing trials and clinical pathways to address COPD earlier in the life course, particularly in the absence of a universally accepted definition of COPD.The reviews of this paper are available via the supplemental material section.

Phosphodiesterase-4 Inhibitors for the Treatment of Inflammatory Diseases

Phosphodiesterase-4 (PDE4), mainly present in immune cells, epithelial cells, and brain cells, manifests as an intracellular non-receptor enzyme that modulates inflammation and epithelial integrity. Inhibition of PDE4 is predicted to have diverse effects via the elevation of the level of cyclic adenosine monophosphate (cAMP) and the subsequent regulation of a wide array of genes and proteins. It has been identified that PDE4 is a promising therapeutic target for the treatment of diverse pulmonary, dermatological, and severe neurological diseases. Over the past decades, numerous PDE4 inhibitors have been designed and synthesized, among which roflumilast, apremilast, and crisaborole were approved for the treatment of inflammatory airway diseases, psoriatic arthritis, and atopic dermatitis, respectively. It is regrettable that the dramatic efficacies of a drug are often accompanied by adverse effects, such as nausea, emesis, and gastrointestinal reactions. However, substantial advances have been made to mitigate the adverse effects and obtain better benefit-to-risk ratio. This review highlights the dialectical role of PDE4 in drug discovery and the disquisitive details of certain PDE4 inhibitors to provide an overview of the topics that still need to be addressed in the future.

Cilostazol, a phosphodiesterase 3 inhibitor, activates proteasome-mediated proteolysis and attenuates tauopathy and cognitive decline

Alzheimer's disease and several variants of frontotemporal degeneration including progressive supranuclear palsy and corticobasal degeneration are characterized by the accumulation of abnormal tau protein into aggregates. Most proteins, including tau, are degraded via the ubiquitin proteasome system, but when abnormal tau accumulates, the function of 26S proteasomes is downregulated. The negative effect of tau aggregates on the function of the proteasome can have deleterious consequences on protein homeostasis and disease progression. Developing therapies aimed at clearing abnormal tau are thus of considerable interest. In the present study, we investigated the effect of cilostazol, an FDA-approved selective phosphodiesterase 3 inhibitor, on a mouse model of tauopathy (line rTg4510). Administration of cilostazol for 30 days enhanced proteasome function via the cyclic adenosine 3',5'-monophosphate/protein kinase A pathway and attenuated tauopathy and cognitive decline in rTg4510 mice. These results suggest that cilostazol, or other FDA-approved drugs acting via the same pathway, has the potential to be repurposed for the treatment of patients with early-stage tauopathy.

Anti-inflammatory effects of the novel inhaled phosphodiesterase type 4 inhibitor CHF6001 on virus-inducible cytokines

Respiratory virus infections precipitate asthma and chronic obstructive pulmonary disease (COPD) exacerbations, with most exacerbations due to rhinovirus infection. Both asthma and COPD exacerbations are not well controlled by steroid therapies, and there is a much research interest in finding improved therapies or combinations of therapies for controlling exacerbations. CHF6001 is a new, inhaled highly potent and selective phosphodiesterase type 4 (PDE4) inhibitor. Using in vitro human bronchial epithelial cells (BEAS‐2B), we investigated the potential anti‐inflammatory effects of CHF6001 on rhinovirus (RV1B)‐induced cytokines. Cytokine mRNA was measured by real‐time PCR, while protein release was measured by ELISA. CHF6001 was used in a 7‐point dose–response curve (1000–0.001 nmol/L) as a 1.5‐h pretreatment prior to infection in comparison with roflumilast. Both roflumilast and CHF6001 reduced RV1B‐induced IL‐8, IL‐29, IP‐10, and RANTES mRNA and protein in a concentration‐dependent manner. Generally, CHF6001 was 13‐ to 16‐fold more potent (subnanomolar EC₅₀ values) than roflumilast at reducing IL‐8, IL‐29, IP‐10, and RANTES mRNA and protein release, but had similar efficacies. In combination with the steroid fluticasone propionate (1 nmol/L), CHF6001 had additive effects, significantly reducing RV‐induced cytokines when compared with steroid or CHF6001 alone. Combined low‐dose steroid and low‐dose CHF6001 had a similar efficacy as high‐dose steroid or CHF6001 alone, indicating the combination had steroid and PDE4 inhibitor sparing effects. Overall results indicate that PDE4 inhibitors have anti‐inflammatory activity against virus‐induced inflammatory mediators and that CHF6001 is more potent than roflumilast.

Genome Expression Profiling-Based Identification and Administration Efficacy of Host-Directed Antimicrobial Drugs against Respiratory Infection by Nontypeable Haemophilus influenzae

Therapies that are safe, effective, and not vulnerable to developing resistance are highly desirable to counteract bacterial infections. Host-directed therapeutics is an antimicrobial approach alternative to conventional antibiotics based on perturbing host pathways subverted by pathogens during their life cycle by using host-directed drugs. In this study, we identified and evaluated the efficacy of a panel of host-directed drugs against respiratory infection by nontypeable Haemophilus influenzae (NTHi). NTHi is an opportunistic pathogen that is an important cause of exacerbation of chronic obstructive pulmonary disease (COPD). We screened for host genes differentially expressed upon infection by the clinical isolate NTHi375 by analyzing cell whole-genome expression profiling and identified a repertoire of host target candidates that were pharmacologically modulated. Based on the proposed relationship between NTHi intracellular location and persistence, we hypothesized that drugs perturbing host pathways used by NTHi to enter epithelial cells could have antimicrobial potential against NTHi infection. Interfering drugs were tested for their effects on bacterial and cellular viability, on NTHi-epithelial cell interplay, and on mouse pulmonary infection. Glucocorticoids and statins lacked in vitro and/or in vivo efficacy. Conversely, the sirtuin-1 activator resveratrol showed a bactericidal effect against NTHi, and the PDE4 inhibitor rolipram showed therapeutic efficacy by lowering NTHi375 counts intracellularly and in the lungs of infected mice. PDE4 inhibition is currently prescribed in COPD, and resveratrol is an attractive geroprotector for COPD treatment. Together, these results expand our knowledge of NTHi-triggered host subversion and frame the antimicrobial potential of rolipram and resveratrol against NTHi respiratory infection.

Roflumilast, a phosphodiesterase-4 inhibitor, induces phagocytic activity in Greek COPD patients

Background

A new approach to the treatment of COPD includes controlling inflammation because of its important role in exacerbation of the disease. Recently, roflumilast has been added as a therapeutic option for COPD. Roflumilast is an oral phosphodiesterase-4 inhibitor that targets inflammatory cells involved in triggering exacerbations of COPD. The objective of the current study was to evaluate roflumilast for its contribution to phagocytic activity in COPD patients.

Methods

Twenty-one patients diagnosed with COPD received roflumilast once daily for 6 months in combination with fluticasone (an inhaled corticosteroid), salmeterol (a long-acting β2-agonist), and tiotropium (a long-acting muscarinic antagonist) or combinations of these agents. The main inclusion criterion was stable disease for at least the previous 30 days. Neutrophils and spirometric changes, ie, forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC), were measured in the COPD patients at indicated time points. The first sample was taken before receiving roflumilast, the second 3 months later, and the third after 6 months. Examination of defective phagocytosis was done by flow cytometry using a FagoFlowEx^® kit. The statistical analysis was performed using Statistica software.

Results

Our results indicate that phagocytic activity was increased after 3 and 6 months of treatment when compared with baseline (P<0.001). Similarly, FVC and FEV₁ were also increased during the 6-month period, but only FVC differed significantly from baseline (P<0.001).

Conclusion

Although the number of patients in this study was limited, our results indicate that roflumilast induces phagocytic activity, which improves lung function.

Roflumilast-induced Local Vascular Injury Is Associated with a Coordinated Proteome and Microparticle Change in the Systemic Circulation in Pigs

Drug-induced vascular injury (DIVI) is commonly associated with phosphodiesterase (PDE) inhibitors. Despite histological characterization, qualified biomarkers for DIVI detection are lacking. We investigated whether a single administration of roflumilast (PDE-IV inhibitor) induces vascular damage and identified novel surrogate biomarkers of acute vascular injury. Pigs received postoperative 250, 375, or 500 μg of roflumilast or placebo/control. After 1.5 hr, coronary reactivity was determined by catheter-based administration of acetylcholine and sodium nitroprusside (SNP) in the coronary sinus. Immunohistochemical analysis of vessel integrity (von Willebrand factor [vWF]) and fibrin(ogen) deposition was performed in the coronary artery and aorta. Peripheral blood was collected for differential proteomics and microparticles analysis. Circulating interleukin (IL)-6 was analyzed. Roflumilast-treated animals displayed higher vasodilation to acetylcholine and SNP versus controls (p < .05). Roflumilast-treated animals showed a dose-dependent (p < .05) decrease in vessel integrity and dose-dependent increase in fibrin deposition forming a continuous layer at roflumilast-500 μg. Peripheral blood of roflumilast-500-μg-treated animals showed increased levels of total and endothelial-derived microparticles and exhibited a coordinated change in proteins kininogen-1, endothelin-1, gelsolin, apolipoprotein A-I, and apolipoprotein-J associated with vascular injury (p < .05 vs. controls). IL-6 remained unaltered. Roflumilast-induced vascular injury can be detected by novel markers in peripheral blood. Validation of these surrogate markers in human samples seems required.

Head and neck cancers, the neglected malignancies: present and future treatment strategies

Head and neck cancers are the most prevalent cancers in Asia and result in 50% of deaths due to all cancers in that region. However, treatment regimen has not changed in the past two decades and there are no specific drugs for this cancer. As a result of this, treatment outcomes remain poor. Furthermore, there are no new breakthrough therapies on the horizon, in part, due to low commercial interest in these cancers. What is needed is new thinking, which combines targeted and risk mitigation approaches to develop novel drugs. This editorial will focus on summarising the present approaches to treatment and propose new targets for these cancers.