Effects of in vitro amiodarone exposure on alveolar macrophage inflammatory mediator production

Plasticity towards Rigidity: A Macrophage Conundrum in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive, chronic, and ultimately fatal diffuse parenchymal lung disease. The molecular mechanisms of fibrosis in IPF patients are not fully understood and there is a lack of effective treatments. For decades, different types of drugs such as immunosuppressants and antioxidants have been tested, usually with unsuccessful results. Although two antifibrotic drugs (Nintedanib and Pirfenidone) are approved and used for the treatment of IPF, side effects are common, and they only slow down disease progression without improving patients’ survival. Macrophages are central to lung homeostasis, wound healing, and injury. Depending on the stimulus in the microenvironment, macrophages may contribute to fibrosis, but also, they may play a role in the amelioration of fibrosis. In this review, we explore the role of macrophages in IPF in relation to the fibrotic processes, epithelial–mesenchymal transition (EMT), and their crosstalk with resident and recruited cells and we emphasized the importance of macrophages in finding new treatments.

Acute Amiodarone Pulmonary Toxicity

Amiodarone is an effective antiarrhythmic that frequently is used during the perioperative period. Amiodarone possesses a significant adverse reaction profile. Amiodarone-induced pulmonary toxicity (AIPT) is among the most serious adverse effects and is a leading cause of death associated with its use. Despite significant advances in the understanding of AIPT, its etiology and pathogenesis remain incompletely understood. The diagnosis of AIPT is one of exclusion. The clinical manifestations of AIPT are categorized broadly as acute, subacute, and chronic. Acute AIPT is a rarer and more aggressive form of the disease, most often encountered in cardiothoracic surgery. Acute respiratory distress syndrome (ARDS) is the predominating pattern of amiodarone's acute pulmonary toxicity. The incidence, risk factors, pathogenesis, and diagnosis of acute AIPT are speculative. Early cardiothoracic literature investigating AIPT often attributed amiodarone to the development of postoperative ARDS. Subsequent studies have found no association between amiodarone and acute AIPT and ARDS development. As a drug that is frequently prescribed to a patient population deemed most at risk for this fatal disease, the conflicting evidence on acute AIPT needs further investigation and clarification.

Effect of Aronia melanocarpa fruit juice on amiodarone-induced pneumotoxicity in rats

Background:

The fruits of Aronia melanocarpa (Michx.) Elliot is extremely rich in biologically active polyphenols.

Objective:

We studied the protective effect of A. melanocarpa fruit juice (AMFJ) in a model of amiodarone (AD)-induced pneumotoxicity in rats.

Materials and Methods:

AD was instilled intratracheally on days 0 and 2 (6.25 mg/kg). AMFJ (5 mL/kg and 10 mL/kg) was given orally from day 1 to days 2, 4, 9, and 10 to rats, which were sacrificed respectively on days 3, 5, 10, and 28 when biochemical, cytological, and immunological assays were performed.

Results:

AMFJ antagonized AD-induced increase of the lung weight coefficient. In bronchoalveolar lavage fluid, AD increased significantly the protein content, total cell count, polymorphonuclear cells, lymphocytes and the activity of lactate dehydrogenase, acid phosphatase and alkaline phosphatase on days 3 and 5. In AMFJ-treated rats these indices of direct toxic damage did not differ significantly from the control values. In lung tissue, AD induced oxidative stress measured by malondialdehyde content and fibrosis assessed by the hydroxyproline level. AMFJ prevented these effects of AD. In rat serum, AD caused a significant elevation of interleukin IL-6 on days 3 and 5, and a decrease of IL-10 on day 3. In AMFJ-treated rats, these indices of inflammation had values that did not differ significantly from the control ones.

Conclusion:

AMFJ could have a protective effect against AD-induced pulmonary toxicity as evidenced by the reduced signs of AD-induced direct toxic damage, oxidative stress, inflammation, and fibrosis.

The role of induced sputum in amiodarone-associated interstitial lung diseases

Amiodarone, a highly effective medication for suppressing cardiac rhythm disturbances, may cause pulmonary injury, such as chronic interstitial lung diseases, in 5-15% of the patients who take it. We applied induced sputum (IS), a non-invasive technique, for diagnosing amiodarone-induced pulmonary toxicity. Four patients with interstitial lung disease who were treated by amiodarone for ischemic heart diseases were evaluated by a conventional clinical workup. All four patients showed marked interstitial pattern on computerized tomography and decreased diffusion capacity (DLCO-SB 51-76%). IS showed lymphocytosis, a high CD4 or CD8 count, eosinophilia and amiodarone in 3 of 4 patients. IS may be a useful tool for assessing amiodarone toxicity in patients with ischemic heart diseases and concomitant pulmonary side effects.

Is amiodarone an underrecognized cause of acute respiratory failure in the ICU?

Amiodarone is a commonly used anti-arrhythmic agent, with well-recognized chronic toxicity. Less well known is amiodarone's potential to cause acute lung damage, which can be severe or, occasionally, life-threatening. Lungs that have already been exposed to physical insults, such as the lungs of patients undergoing cardiac surgery, are particularly susceptible to acute pulmonary toxicity (APT). Unfortunately, cardiac surgery is one of the clinical scenarios in which amiodarone is most commonly used. After reviewing the data, and even in the context of difficulties and discrepancies in the existing literature, we contend that there is sufficient evidence of amiodarone's potentially serious side-effect profile in surgical ICU patients to advise continued caution in its use with this severely ill patient group. We suggest that amiodarone has a potentially important, though underrecognized, role in inducing an APT/ARDS in some patients, such as those undergoing cardiac surgery. We also provide a hypothesis to explain the mechanism by which amiodarone causes lung damage.