Aldosterone and interleukin-6: the synergic effect in COVID-19

Aims Several evidence have identified the role of Interleukin-6 (IL-6) in the cytokine storm induced by COVID-19. Interestingly, the correlation between the serum levels of IL-6 and the plasma aldosterone has already been demonstrated in patients affected by primary aldosteronism (PA). Thus, we suppose that hyperaldosteronism may increase IL-6 levels in COVID-19. Methods and results We report a case of 47-year-old female Covid-19 patient who had developed severe pneumonia complicated by Guillain–Barreé syndrome (GBS). Blood test revealed high levels of IL-6 (serum IL-6: 402 pg/ml) and of its soluble receptor (soluble IL-6 receptor >1900 pg/ml) and she required mechanical ventilation for severe hypoxaemia. Furthermore, the evidence of right adrenal adenoma, resistant hypertension, severe hypokalaemia, and high serum levels of aldosterone with high aldosterone/renin ratio were also consistent with diagnosis of PA. Thus, Spironolactone was administered with rapid improvements in clinical condition. Finally, she was diagnosed with acute motor sensitive neuropathy and started the rehabilitation phase. Conclusions Elevated aldosterone levels in PA may stimulate IL-6 production, inducing more severe forms of COVID-19 with the development of serious complications such as GBS. Hyperaldosteronism may also contribute to the poorest prognosis of patients with secondary aldosteronism such as heart failure and COVID-19, in which elevated IL-6 levels could exert its detrimental effects, mostly on the progression of ventricular dysfunction. Further studies are necessary to evaluate therapy with mineralocorticoid receptors antagonists such as spironolactone in COVID-19.

The elderly at risk: aldosterone as modulator of the immune response to SARS-CoV-2 infection.

The elderly population is the most susceptible to SARS-CoV-2 infection and develops the worst clinical phenotype with severe pneumonia and cardiac complications. Older COVID-19 patients are also at higher risk of sudden death, mainly attributable to electrolyte disorders and to an uncontrolled inflammatory response. After the identification of ACE 2 as the receptor of SARS-CoV-2 in human cells, several research studies have focused on the role of the activation of Renin Angiotensin System in COVID-19 clinical course. In the present opinion paper, we discuss the role of hyperaldosteronism in the increasing risk of cardiac complications in COVID-19 older patients. In particular, we focus on the immunoregulatory activity of aldosterone, as the last mediator of the Renin Angiotensin System cascade, in activating the innate and adaptive immune response related to SARS-CoV-2 infection in the elderly. Aldosterone may stimulate dendritic cells and the recruitment of monocytes/macrophages in the endothelium of coronary vessels, favoring the production of pro-inflammatory mediators and T-cells response. Higher basal levels of aldosterone together with SARS-CoV-2-induced production may explain the unfavorable course of COVID-19 in the elderly.

Dendritic Cells and SARS-CoV-2 Infection: Still an Unclarified Connection.

The ongoing pandemic due to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has so far infected about 2.42 × 107 (as at 27 August 2020) subjects with more than 820,000 deaths. It is the third zoonotic coronavirus-dependent outbreak in the last twenty years and represents a major infective threat for public health worldwide. A main aspect of the infection, in analogy to other viral infections, is the so-called "cytokine storm", an inappropriate molecular response to virus spread which plays major roles in tissue and organ damage. Immunological therapies, including vaccines and humanized monoclonal antibodies, have been proposed as major strategies for prevention and treatment of the disease. Accordingly, a detailed mechanistic knowledge of the molecular events with which the virus infects cells and induces an immunological response appears necessary. In this review, we will report details of the initial process of SARS-CoV-2 cellular entry with major emphasis on the maturation of the spike protein. Then, a particular focus will be devoted to describe the possible mechanisms by which dendritic cells, a major cellular component of innate and adaptive immune responses, may play a role in the spread of the virus in the human body and in the clinical evolution of the disease.