Ketanserin as potential additive drug to improve V/Q mismatch in COVID-19?

The relationship between the serotonergic system and COVID-19 disease: A review

COVID-19 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which led to a pandemic started in Wuhan, China, in 2019. The rapid spread of the disease in the world, unprecedented mortality rate, and lack of definitive treatment for the disease have led to a global effort to develop effective vaccines as well as new therapeutic interventions. Immune cells activation with excessive inflammation is an important pathophysiological feature of COVID-19 that may impair the various organs functions. Accordingly, these could cause dysfunction in the brain with some symptoms such as respiratory failure, headache, impaired consciousness, olfactory and taste disorders, and severe neurological disorders such as encephalitis. It was found that there is a two-way communication between the immune system and the nervous system through classical neurotransmitters, hormones, and cytokines. Among neurotransmitters, serotonin plays important roles in the immune system and in regulating inflammatory responses by central and peripheral mechanisms. This article aimed to review the two-way relationship between the immune and the nervous systems by focusing on the serotonergic system and the emerging COVID-19 disease.

Pharmacological and non-pharmacological strategies in coronavirus disease 2019: A literature review

The impact on mortality associated with covid-19 today exceeds five million deaths worldwide, and the number of deaths continues to rise. The complications of the survivors, socio-economic implications at a global level, economic limitations in the health systems, and physical and emotional exhaustion of health personnel are detrimental. Therapeutic strategies are required to limit the evolution of the disease, improve the prognosis of critically ill patients, and, in countries with low purchasing power, create affordable alternatives that can help contain the evolution towards the severity of infected people with mild to moderate symptoms. The misinformation and myths that today are more frequent on social networks and the implementation of practices without scientific support is a problem that aggravates the general panorama. This review aims to concentrate on the best evidence for treating SARS-CoV-2 infection in a simple and summarized manner, addressing therapies from their bases to the most innovative alternatives available today.

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The pathophysiological bases of classic ADRS differ significantly from those related to ARDS due to COVID-19.

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The therapeutic objective based on the pathophysiological aspects could improve the clinical evolution of the affected patients.

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The objectives set for oxygen saturation should be reconsidered since oxygen in high concentrations could have deleterious effects, especially in this patient population.

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Extracorporeal membrane circulation should not be left aside, and early implementation could save many lives in well-selected patients.

Incidental detection of a lung perfusion defect suspicious of pulmonary embolism on labelled white blood cell quality control imaging—case report

Background

Incidental findings could be a very important observation in various nuclear medicine studies. There have been few cases of incidental findings of perfusion abnormalities on early quality control images of the lungs during radiolabeled white blood cell studies. This study is the first to detect perfusion defects on the early quality control images of the lungs during a labelled white blood cell study suspicious of pulmonary embolism in an unknown but treated COVID-19 patient.

Case presentation

We present a 40-year-old male who was referred to our department for a nuclear medicine 99mTc HMPAO-labelled white blood cell study to rule out osteomyelitis of his right foot. Early 5-min quality control images of his lungs revealed two perfusion defects in the right lung. A suspicion of pulmonary embolism was made, and a perfusion only SPECT/CT study the next day confirmed the suspicion of pulmonary embolism in one of the defects, with a possible fissure sign as a differential.

Conclusion

There has been an increase in the incidence of lung perfusion abnormalities and pulmonary embolism during the COVID-19 pandemic. Some of these may be detected as incidental findings on early lung quality control images of radiolabeled white blood cell studies.

The roles of serotonin in cell adhesion and migration, and cytoskeletal remodeling

Serotonin is well known as a neurotransmitter. Its roles in neuronal processes such as learning, memory or cognition are well established, and also in disorders such as depression, schizophrenia, bipolar disorder, and dementia. However, its effects on adhesion and cytoskeletal remodelling which are strongly affected by 5-HT receptors, are not as well studied with some exceptions for e.g. platelet aggregation. Neuronal function is strongly dependent on cell-cell contacts and adhesion-related processes. Therefore the role played by serotonin in psychiatric illness, as well as in the positive and negative effects of neuropsychiatric drugs through cell-related adhesion can be of great significance. In this review, we explore the role of serotonin in some of these aspects based on recent findings.

Lung perfusion findings on perfusion SPECT/CT imaging in non-hospitalized de-isolated patients diagnosed with mild COVID-19 infection

Background

The aim of this retrospective study is to assess the incidence and type of lung perfusion abnormalities in non-hospitalized patients diagnosed with mild COVID-19 infection after de-isolation. Data from 56 non-hospitalized patients diagnosed with COVID-19 infection referred to our nuclear medicine department from July–December 2020 for a perfusion only SPECT/CT study or a ventilation perfusion SPECT/CT study were collected. Images were assessed for the presence and type of perfusion defects. The CT component of the study was also assessed for the presence of mosaic attenuation and COVID pneumonia changes.

Results

Thirty-two (57.1%) cases had perfusion defects. There were 20 (35.7%) cases with defects in keeping with pulmonary embolism, 17 (30.4%) cases with defects associated with mosaic attenuation but not due to pulmonary embolism, and 6 (10.7%) of cases with defects due to pulmonary infiltrates from COVID pneumonia. A total of 24 (42.9%) cases had mosaic attenuation on CT, with 10 (17.9%) of them showing a pattern likely consistent with shunting on the perfusion images.

Conclusion

Lung perfusion abnormalities are a common finding in non-hospitalized COVID-19 patients with mild disease. They are usually either due to pulmonary embolism, parenchymal infiltrates, or other causes of mosaic attenuation related to, but not specific to the pathophysiology of COVID-19 infection. The value of VQ SPECT/CT imaging is also shown in this study, in detecting and differentiating the various types of perfusion abnormalities.

Targeting the Complement Serine Protease MASP-2 as a Therapeutic Strategy for Coronavirus Infections

MASP-2, mannose-binding protein-associated serine protease 2, is a key enzyme in the lectin pathway of complement activation. Hyperactivation of this protein by human coronaviruses SARS-CoV, MERS-CoV and SARS-CoV-2 has been found to contribute to aberrant complement activation in patients, leading to aggravated lung injury with potentially fatal consequences. This hyperactivation is triggered in the lungs through a conserved, direct interaction between MASP-2 and coronavirus nucleocapsid (N) proteins. Blocking this interaction with monoclonal antibodies and interfering directly with the catalytic activity of MASP-2, have been found to alleviate coronavirus-induced lung injury both in vitro and in vivo. In this study, a virtual library of 8736 licensed drugs and clinical agents has been screened in silico according to two parallel strategies. The first strategy aims at identifying direct inhibitors of MASP-2 catalytic activity, while the second strategy focusses on finding protein-protein interaction inhibitors (PPIs) of MASP-2 and coronaviral N proteins. Such agents could represent promising support treatment options to prevent lung injury and reduce mortality rates of infections caused by both present and future-emerging coronaviruses. Forty-six drug repurposing candidates were purchased and, for the ones selected as potential direct inhibitors of MASP-2, a preliminary in vitro assay was conducted to assess their interference with the lectin pathway of complement activation. Some of the tested agents displayed a dose-response inhibitory activity of the lectin pathway, potentially providing the basis for a viable support strategy to prevent the severe complications of coronavirus infections.