Inflammasome signalling pathway in the regulation of inflammation - its involvement in the development and exacerbation of asthma and chronic obstructive pulmonary disease.

Inflammasomes are multiprotein oligomers, whose main function is the recruitment and activation of caspase-1, which cleaves the precursor forms of interleukin (IL)-1ß and IL-18, generating biologically active cytokines. Activation of inflammasome is an essential component of the innate immune response, and according to recent reports it is involved in epithelial homeostasis and type 2 T helper cell (Th2) differentiation. In recent years, the contribution of inflammasome dependent signalling pathways to the development of inflammatory diseases became a topic of multiple research studies. Asthma and chronic obstructive pulmonary disease (COPD) are the most prevalent obstructive lung diseases. Recent studies have focused on inflammatory aspects of asthma and COPD development, demonstrating the key role of inflammasome-dependent processes. Factors responsible for activation of inflammasome complex are similar in both asthma and COPD and include bacteria, viruses, cigarette smoke, and particulate matter. Some recent studies have revealed that NLRP3 inflammasome plays a crucial role, particularly in the development of acute exacerbations of COPD (AECOPD). Activation of NLRP3 inflammasome has been linked with neutrophilic severe steroid-resistant asthma. Although most of the studies on inflammasomes in asthma and COPD focused on the NLRP3 inflammasome, there are scarce scientific reports linking other inflammasomes such as AIM2 and NLRP1 with obstructive lung diseases. In this mini review we focus on the role of molecular pathways associated with inflammasome in the most prevalent lung diseases such as asthma and COPD. Furthermore, we will try to answer the question of whether inhibition of inflammasome can occur as a modern therapy in these diseases.

COEXISTENCE OF PULMONARY FIBROSIS AND PROLIFERATION OF PULMONARY NEUROENDOCRINE CELLS FORMING TUMORLET.

Tumorlet is a disease rarely diagnosed in clinical practice. It is characterized by pulmonary neuroendocrine cell (PNEC) proliferation which invades the bronchiolar basement membrane and forms nodules with a diameter smaller than 5 mm. Case report: 72-year-old female patient was suffered for many years from progressive dyspnea and coughing with evidence of pulmonary fibrosis on high resolution computed tomography (HRCT). As a result of a lung biopsy, based on immunohistochemical tests, a 2 mm cluster of neuroendocrine cells (NEC) was found and it was diagnosed as tumorlet. Due to a long-term, insidious progress of the disease, as well as sex and age of the patient, the case emphasizes that differential diagnosis should include tumorlet as well as diffuse idiopathic neuroendocrine cell hyperplasia (DIPNECH) as a more extensive manifestation of neuroendocrine cell proliferation in the respiratory tract.

[Pulmonary manifestations of crohn's disease or chronic pharmacotherapy complications? - case report].

Pareneteral manifestations of Crohn's disease (ChLC), apart from the most common skin and joint symptoms include also complications from the respiratory system. In addition chronic pharmacotherapy of ChLC, especially 5-aminosalicylic acid or anti-TNF- α drugs, is associated with possible pulmonologic side effects, sometimes difficult to differentiate. In this study, we describe a patient with ChLC, with a history of pneumocystic pneumonia, who was diagnosed with exfoliative institial pneumonitis as a result of chronic use of mesalazine. This disease is characterized by accumulation of alveolar macrophages in the lumen of the alveoli and intrabepticular septum. The most common etiologic factor is exposure to tobacco smoke. Our patient, non-smoker, was finally diagnosed after lung biopsy and histopathological evaluation. The gradual clinical improvement after mesalazine was an additional factor confirming the etiology of the disease. This side effect of mesalazine is not common but it should be considered in all patient treated with 5-aminosalicylic acid.

Neprilysin inhibitors as a new approach in the treatment of right heart failure in the course of chronic obstructive pulmonary disease.

The aim of the study was to find out scientific evidence on the possible use of the combined angiotensin II receptor antagonist and neprilysin inhibitors (ARNI) in patients with right heart failure (RHF) in the course of chronic obstructive pulmonary disease (COPD). It has been proven that a lack of neprilysin or its reduced expression in hypoxia leads to exacerbation of pulmonary arterial remodelling (PAR) or pulmonary hypertension (PH) in the mechanism related to the platelet-derived growth factor (PDGF) resulting in the proliferation and migration of pulmonary artery smooth muscle cells and endothelial-to-mesenchymal transition. Such action in the course of COPD can lead to RHF, which would signify noxious effect of this group of drugs. However, the inhibition of neprilysin also inhibits natriuretic peptide metabolism. The representative of this group - brain natriuretic peptide (BNP) - acts as a vasodilator and also exerts an anti-proliferative activity through the cGMP-dependent protein kinase G pathway. Additionally, it causes bronchodilation by inducing the release of acetylcholine from bronchial epithelial cells. This suggests that natriuretic peptides may appear to be a potential treatment agent in patients with cardiac complications and COPD. Their effects associated with the immunosuppression capacity by reducing the release of inflammatory mediators - IL-6, IL-1ß, and TNF-α can bring benefits to patients with acute lung injury caused by pulmonary inflammation during COPD exacerbations. Considering the potentially positive effect of natriuretic peptides in this group of patients, further research is required in this area, which can provide strong scientific data demonstrating the need for introducing ARNI drugs to the treatment of patients with COPD.