Losartan does not inhibit cigarette smoke-induced lung inflammation in mice

ACE2/ACE imbalance mediates bisphenol A-induced lung injury in Wistar rats: Results from captopril versus losartan histo-biochemical study

Bisphenol-A (BPA) is a synthetic chemical compound broadly used in the plastic and epoxy resin industries with a considerable potential for food contamination. Literary reports have suggested that the altered renin-angiotensin system (RAS) is a mechanism for lung injury and inflammation caused by variable agents. The current study sought to investigate the contribution of RAS to BPA-induced lung damage. Moreover, the study assessed whether angiotensin II and/or bradykinin pathways were involved. For this aim, the angiotensin-converting enzyme (ACE) inhibitor captopril (Cap), either alone or combined with bradykinin receptor antagonist icatibant (Icat), was attempted versus the angiotensin receptor blocker losartan (Los). An eight-week study was conducted on forty Wistar male albino rats randomly divided into five equal groups: control, BPA, BPA/Cap, BPA/Los, and BPA/Cap/Icat groups. Captopril (100 mg/mL) and losartan (200 mg/mL) were given orally in drinking water, but icatibant (Icat) was injected subcutaneously (250 μg/kg) during the last two weeks of captopril treatment. Biochemical analysis of bronchoalveolar lavage fluid (BALF) and lung tissues, polymerase chain reaction (PCR) assay for ACE, ACE2, and caspase-3 genes expression, and histological and immunohistochemical studies were carried out to evaluate BPA-mediated pulmonary inflammation/apoptosis. BPA impaired the histological structure of the lungs, increased ACE, ACE2, and caspase-3 expressions at both gene/protein levels, and increased BALF inflammatory cytokines and lung oxidative markers. Inhibiting the ACE activity by captopril maintained the histological lung injury score, restored inflammation and the ACE2/ACE balance, and decreased apoptosis. Further improvement was obtained by the angiotensin II receptor (ATR1) blocker losartan. Icatibant (bradykinin B2 receptor blocker) didn't counteract the observed captopril effects. It was strongly suggested that RAS contributed to BPA-induced lung damage via alteration of ACE2 and ACE expression mediating angiotensin II generation rather than bradykinin.

Cigarette smoke-induced pulmonary impairment is associated with social recognition memory impairments and alterations in microglial profiles within the suprachiasmatic nucleus of the hypothalamus

Chronic obstructive pulmonary disease (COPD) is a major, incurable respiratory condition that is primarily caused by cigarette smoking (CS). Neurocognitive disorders including cognitive dysfunction, anxiety and depression are highly prevalent in people with COPD. It is understood that increased lung inflammation and oxidative stress from CS exposure may 'spill over' into the systemic circulation to promote the onset of these extra-pulmonary comorbidities, and thus impacts the quality of life of people with COPD. The precise role of the 'spill-over' of inflammation and oxidative stress in the onset of COPD-related neurocognitive disorders are unclear. The present study investigated the impact of chronic CS exposure on anxiety-like behaviors and social recognition memory, with a particular focus on the role of the 'spill-over' of inflammation and oxidative stress from the lungs. Adult male BALB/c mice were exposed to either room air (sham) or CS (9 cigarettes per day, 5 days a week) for 24 weeks and were either daily co-administered with the NOX2 inhibitor, apocynin (5 mg/kg, in 0.01 % DMSO diluted in saline, i.p.) or vehicle (0.01 % DMSO in saline) one hour before the initial CS exposure of the day. After 23 weeks, mice underwent behavioral testing and physiological diurnal rhythms were assessed by monitoring diurnal regulation profiles. Lungs were collected and assessed for hallmark features of COPD. Consistent with its anti-inflammatory and oxidative stress properties, apocynin treatment partially lessened lung inflammation and lung function decline in CS mice. CS-exposed mice displayed marked anxiety-like behavior and impairments in social recognition memory compared to sham mice, which was prevented by apocynin treatment. Apocynin was unable to restore the decreased Bmal1-positive cells, key in cells in diurnal regulation, in the suprachiasmatic nucleus of the hypothalamus to that of sham levels. CS-exposed mice treated with apocynin was associated with a restoration of microglial area per cell and basal serum corticosterone. This data suggests that we were able to model the CS-induced social recognition memory impairments seen in humans with COPD. The preventative effects of apocynin on memory impairments may be via a microglial dependent mechanism.

Challenges of COPD Patients during the COVID-19 Pandemic

Coronavirus disease 2019 (COVID-19) is a severe systemic infection that is a major threat to healthcare systems worldwide. According to studies, chronic obstructive pulmonary disease (COPD) patients with COVID-19 usually have a high risk of developing severe symptoms and fatality, but limited research has addressed the poor condition of COPD patients during the pandemic. This review focuses on the underlying risk factors including innate immune dysfunction, angiotensin converting enzyme 2 (ACE2) expression, smoking status, precocious differentiation of T lymphocytes and immunosenescence in COPD patients which might account for their poor outcomes during the COVID-19 crisis. Furthermore, we highlight the role of aging of the immune system, which may be the culprit of COVID-19. In brief, we list the challenges of COPD patients in this national pandemic, aiming to provide immune-related considerations to support critical processes in COPD patients during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and inspire immune therapy for these patients.

MicroRNA-101-3p Suppresses mTOR and Causes Mitochondrial Fragmentation and Cell Degeneration in COPD

BACKGROUND

Cigarette smoke is assumed to cause the loss of airway wall structure in chronic obstructive pulmonary disease (COPD) by reducing airway smooth muscle cell (ASMC) function. It also modifies mTOR activity, microRNA (miR)-101-3p expression, and mitochondria function. Here, the link between miR-101-3p and mTOR-regulated mitochondria integrity and ASMC deterioration was assessed.

METHODS

Disease-specific miR-101-3p expression was determined by RT-PCR in primary ASMC (non-COPD smokers: n = 6; COPD: n = 8; healthy: n = 6). The regulatory effect of miR-101-3p modification on mTOR expression, mitochondrial fragmentation, and remodeling properties (α-SMA, fibronectin, MTCO2, and p70S6 kinase) was assessed in ASMC (healthy nonsmokers: n = 3; COPD: n = 3) by Western blotting and immunofluorescence microscopy. MiR-101-3p was modified by specific mimics or inhibitors, in ASMC stimulated with TNF-α (10 ng/ml) or cigarette smoke extract (CSE).

RESULTS

MiR-101-3p expression was significantly higher in ASMC of COPD patients, compared to ASMC of healthy or active smokers. MiR-101-3p expression was increased by TNF-α or CSE. TNF-α or miR-101-3p deteriorated ASMC and mitochondria, while decreasing mTOR signaling, α-SMA, fibronectin, and MTCO2. MiR-101-3p inhibition reduced ASMC deterioration and mitochondrial fragmentation.

CONCLUSION

Constitutive high miR-101-3p expression characterizes COPD-ASMC, causing increased mitochondrial fragmentation and ASMC deterioration. Thus, reactivation mTOR or blocking miR-101-3p presents a potential new strategy for COPD therapy.

Renin-angiotensin system antagonists and mortality due to pneumonia, influenza, and chronic lower respiratory disease in patients with hypertension

BACKGROUND

It is controversial whether angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACEI/ARB) have a potentially beneficial role in the respiratory system. This study investigated the association between ACEI/ARB medications and respiratory-related mortality in hypertensive patients in a real-world nationally representative cohort.

METHODS

This was a retrospective analysis based on a prospective cohort study. A total of 10,530 patients with hypertension aged ≥ 20 years were included. The data was extracted from the US National Health and Nutrition Examination Survey during 1988-1994 and 1999-2006. The study was approved by the Institutional Review Boards. Moreover, inform concent was taken form all the participants.

RESULTS

Overall, 27.7% (n = 2920) patients took ACEI/ARB agents. During a median follow-up of 12.4 years, 278 individuals died of respiratory disease, including chronic lower respiratory disease (n = 155) and influenza or pneumonia (n = 123). Compared with the patients without ACEI/ARB use, those taking ACEI/ARB were not associated with respiratory-specific mortality in a multivariable-adjusted Cox model. After 1: 1 matching, taking ACEI/ARB was also not related to respiratory mortality (Hazard ratio (HR) = 1.07, 95% CI: 0.79-1.43), influenza- or pneumonia-related (HR = 1.00, 95% CI: 0.65-1.54) and chronic pulmonary mortality (HR = 1.13, 95% CI: 0.75-1.69). After separating ACEI and ARB from anti-hypertensive medications, those associations remained unchanged.

CONCLUSIONS

We discovered no significant link between ACEI or ARB medication and pulmonary-related mortality in hypertensive patients. In hypertensive patients, standard ACEI/ARB administration may have little effect on the respiratory system.

Ebselen prevents cigarette smoke-induced cognitive dysfunction in mice by preserving hippocampal synaptophysin expression

Background

Cigarette smoking (CS) is the leading cause of chronic obstructive pulmonary disease (COPD). The “spill-over” of pulmonary inflammation into the systemic circulation may damage the brain, leading to cognitive dysfunction. Cessation of CS can improve pulmonary and neurocognitive outcomes, however, its benefit on the neuroinflammatory profile remains uncertain. Here, we investigate how CS exposure impairs neurocognition and whether this can be reversed with CS cessation or an antioxidant treatment.

Methods

Male BALB/c mice were exposed to CS (9 cigarettes/day for 8 weeks) followed by 4 weeks of CS cessation. Another cohort of CS-exposed mice were co-administrated with a glutathione peroxidase mimetic, ebselen (10 mg/kg) or vehicle (5% CM-cellulose). We assessed pulmonary inflammation, spatial and working memory, and the hippocampal microglial, oxidative and synaptic profiles.

Results

CS exposure increased lung inflammation which was reduced following CS cessation. CS caused spatial and working memory impairments which were attributed to hippocampal microglial activation and suppression of synaptophysin. CS cessation did not improve memory deficits or alter microglial activation. Ebselen completely prevented the CS-induced working and spatial memory impairments, which was associated with restored synaptophysin expression without altering microglial activation.

Conclusion

We were able to model the CS-induced memory impairment and microglial activation seen in human COPD. The preventative effects of ebselen on memory impairment is likely to be dependent on a preserved synaptogenic profile. Cessation alone also appears to be insufficient in correcting the memory impairment, suggesting the importance of incorporating antioxidant therapy to help maximising the benefit of cessation.

Immunomodulatory Activity of the Most Commonly Used Antihypertensive Drugs-Angiotensin Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers

This review article is focused on antihypertensive drugs, namely angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB), and their immunomodulatory properties reported in hypertensive patients as well as in experimental settings involving studies on animal models and cell lines. The immune regulatory action of ACEI and ARB is mainly connected with the inhibition of proinflammatory cytokine secretion, diminished expression of adhesion molecules, and normalization of CRP concentration in the blood plasma. The topic has significant importance in future medical practice in the therapy of patients with comorbidities with underlying chronic inflammatory responses. Thus, this additional effect of immune regulatory action of ACEI and ARB may also benefit the treatment of patients with metabolic syndrome, allergies, or autoimmune disorders.