Obesity and COVID-19: what makes obese host so vulnerable?

Abstract

The disease (COVID-19) novel coronavirus pandemic has so far infected millions resulting in the death of over a million people as of Oct 2020. More than 90% of those infected with COVID-19 show mild or no symptoms but the rest of the infected cases show severe symptoms resulting in significant mortality. Age has emerged as a major factor to predict the severity of the disease and mortality rates are significantly higher in elderly patients. Besides, patients with underlying conditions like Type 2 diabetes, cardiovascular diseases, hypertension, and cancer have an increased risk of severe disease and death due to COVID-19 infection. Obesity has emerged as a novel risk factor for hospitalization and death due to COVID-19. Several independent studies have observed that people with obesity are at a greater risk of severe disease and death due to COVID-19. Here we review the published data related to obesity and overweight to assess the possible risk and outcome in Covid-19 patients based on their body weight. Besides, we explore how the obese host provides a unique microenvironment for disease pathogenesis, resulting in increased severity of the disease and poor outcome.

Mild COVID-19 manifestation in multiple risk factor patient on methotrexate, who had been treated with UVB phototherapy and had sufficient plasma 25-OH-vitamin D3 level

“…Almost immediately after the pandemic outbreak in China, greater vulnerability and higher incidence of severe clinical presentation and fatal outcome were observed in patients with particular preexisting conditions, especially in persons aged > 65 1,2 . Numerous studies have shown that the greatest risk of severe COVID-19 course/manifestation is posed by the presence of either diabetes mellitus, obesity, arterial hypertension or immunosuppression / immunodeficiency [3][4][5][6][7][8] . Severe COVID-19 manifestations include development of extensive bilateral pneumonia, ARDS and endothelial damage accompanied with accelerated thrombogenesis, which can all lead to the respiratory and multiorgan failure, being major clinical concern due to intensive care units overcrowding and high mortality rate 4,6 .…”

“…Patients with risk factors more likely react with extremely excessive systemic inflammation resulting with cytokine storm which is considered as an executive pathophysiological mechanism responsible for severe disease manifestations, such as acute respiratory distress syndrome (ARDS), diffuse endothelial damage with accelerated thrombogenesis and multiple organ dysfunction syndrome (MODS) 6 . In most groups of risk patients, common mechanism favoring development of excessive inflammation and cytokine storm is persistently present proinflammatory milieu 7 . Such chronic proinflammatory state can arises either due to hypersecretion of proinflammatory adipokines in obese patients 7 , lack of anti-inflammatory signaling in diabetic and insulinresistant patients 7,8 or dysregulation of renin angiotensin system (RAS) with increased proinflammatory angiotensin II (Ang II) production in hypertensive patients 6,9,10 .…”

“…In most groups of risk patients, common mechanism favoring development of excessive inflammation and cytokine storm is persistently present proinflammatory milieu 7 . Such chronic proinflammatory state can arises either due to hypersecretion of proinflammatory adipokines in obese patients 7 , lack of anti-inflammatory signaling in diabetic and insulinresistant patients 7,8 or dysregulation of renin angiotensin system (RAS) with increased proinflammatory angiotensin II (Ang II) production in hypertensive patients 6,9,10 . Patients on immunosuppressive therapy are considered to be at risk due to the facilitated viral multiplication and dissemination during the initial phase, enabling in turn more vigorous ignition of hyperinflammatory phase 6,10,11 .…”

A Brief Overview of Oxidative Stress in Adipose Tissue with a Therapeutic Approach to Taking Antioxidant Supplements

“…Then, in January 2020, the disease's first cases were reported outside China (one in Japan and two in Thailand). Since then, the disease has spread rapidly to all countries of the world [114,115]. The condition was declared a pandemic on 11 March 2020, by WHO on 11 March 2020, and to date (22 February 2021), the total number of infected patients has reached 112,045,556, of which 2,479,625 people lost their lives (https://www.worldometers.info/coronavirus/, accessed on 20 February 2021).…”

“…As mentioned, obesity is directly related to COVID-19 disease and leads to increased inflammation, mitochondrial dysfunction, and increased ACE2 receptors. Numerous studies have shown that high BMI (≥30 kg/m 2 ) and excess visceral fat (VF) are effective methods in diagnosing the severity of COVID-19, especially in obese patients [115,119,121].…”