Boosting the Immune System with Vitamin D: Special Focus on Prevention of COVID-19 and Complications

In addition to the classical functions of the musculoskeletal system and calcium homeostasis, the function of vitamin D as an immune modulator is well established. The vitamin D receptors and enzymes that metabolize vitamin D are ubiquitously expressed in most cells in the body, including T and B lymphocytes, antigen-presenting cells, monocytes, macrophages and natural killer cells that trigger immune and antimicrobial responses. Many in vitro and in vivo studies revealed that vitamin D promotes tolerogenic immunological action and immune modulation. Vitamin D adequacy positively influences the expression and release of antimicrobial peptides, such as cathelicidin, defensin, and anti-inflammatory cytokines, and reduces the expression of proinflammatory cytokines. Evidence suggestss that vitamin D's protective immunogenic actions reduce the risk, complications, and death from COVID-19. On the contrary, vitamin D deficiency worsened the clinical outcomes of viral respiratory diseases and the COVID-19-related cytokine storm, acute respiratory distress syndrome, and death. The study revealed the need for more preclinical studies and focused on well-designed clinical trials with adequate sizes to understand the role of vitamin D on the pathophysiology of immune disorders and mechanisms of subduing microbial infections, including COVID-19.Copyright © 2023 Bentham Science Publishers.

Pathophysiological Mechanisms of Cardiac Dysfunction in Transgenic Mice with Viral Myocarditis.

Viral myocarditis is pathologically associated with RNA viruses such as coxsackievirus B3 (CVB3), or more recently, with SARS-CoV-2, but despite intensive research, clinically proven treatment is limited. Here, by use of a transgenic mouse strain (TG) containing a CVB3ΔVP0 genome we unravel virus-mediated cardiac pathophysiological processes in vivo and in vitro. Cardiac function, pathologic ECG alterations, calcium homeostasis, intracellular organization and gene expression were significantly altered in transgenic mice. A marked alteration of mitochondrial structure and gene expression indicates mitochondrial impairment potentially contributing to cardiac contractile dysfunction. An extended picture on viral myocarditis emerges that may help to develop new treatment strategies and to counter cardiac failure.

Spike Proteins Increase Endothelial Calcium via TRPV4

Introduction: Endothelial dysfunction plays a central role in the pathogenesis of acute respiratory distress syndrome (ARDS) with COVID-19. Transient receptor potential vanilloid 4 (TRPV4), a cation channel ubiquitously expressed, can regulate inflammatory cytokines that play key roles in in acute lung injury/ARDS. However, it is unknown whether spike proteins can affect TRPV4 activity and related Ca2+]signaling in pulmonary microvascular endothelial cells. Hypothesis: We hypothesized that spike protein causes activation of TRPV4 channels, resulting in increases in intracellular Ca2+], may lead to pulmonary endothelial dysfunction. Method(s): Intracellular Ca2+]concentrations in human lung microvascular endothelial cells (HLMECs) were measured by calcium imaging in the presence of SARS CoV-2 Spike protein S1, receptor-binding domain (RBD) of S1, or protein S2 with or without co-incubation of the selective TRPV4 antagonist (HC-067047). Result(s): The intracellular Ca2+]concentration of HLMECs was significantly increased when incubated with S1 (1, 10nM) or S1 RBD (1, 10nM) for 12, 24, 48 hours, relative to control or S2 (p<0.05, respectively, Fig. A, B). Co-incubation of HC-067047 (500nM) significantly attenuated Ca2+]intracellular influx upon treatment with S1 (10nM, 24 hours, p<0.05) or S1 RBD (10nM, 24 hours, p<0.05) (Fig. C). TRPV4 sensitive current density was significantly increased when incubated with S1 (10nM) or S1 RBD (10nM) for 24 hours (p<0.05 vs. control, respectively, Fig. D-G), whereas co-incubated with HC-067047 (500nM) significantly reversed the S1 (10nM, 24 hours, p<0.05) or S1 RBD (10nM, 24 hours, p<0.05) induced increases of TRPV4 sensitive current density (Fig. D-G). Conclusion(s): The of SARS CoV-2 Spike protein S1 and S1 RBD caused the activation of TRPV4 channels, resulting in increased intracellular Ca2+], may lead to pulmonary endothelial dysfunction. (Figure Presented).

MALIGNANT HYPERTHERMIA AND COVID-19: IS THERE A CORRELATION?

SESSION TITLE: COVID-19 Case Report Posters 2 SESSION TYPE: Case Report Posters PRESENTED ON: 10/19/2022 12:45 pm - 01:45 pm INTRODUCTION: Malignant hyperthermia (MH) is a hypermetabolic crisis where an increase in carbon dioxide is seen despite an increased minute ventilation with a proposed mechanism as a disturbance in calcium homeostasis. Commonly seen in volatile anesthetic agents and depolarizing neuromuscular blockers, rarely with nondepolarizing agents. There has been one reported case of cisatracurium-induced MH in the setting of ARDS. There have been two cases reported of nondepolarizing neuromuscular agents causing MH in the setting of COVID-19. CASE PRESENTATION: A 34-year-old man with severe COVID-19 complicated by ARDS on ventilator day 16, due to refractory fevers, ventilatory dyssynchrony, high minute ventilation and auto-PEEP phenomena, the decision was made to attempt neuromuscular paralysis. After one dose of cisatracurium, the patient became hyperthermic and end-tidal carbon-dioxide increased from 58-98 with inability to oxygenate. The patient developed high peak pressures, bedside ultrasound revealed no evidence of pneumothorax also confirmed with chest x-ray. The patient then received a dose of dantrolene with end-tidal improving to 60 and tachycardia also resolved. A creatinine kinase level drawn was elevated at 571. DISCUSSION: A proposed mechanism of MH is calcium release from sarcoplasmic reticulum, a mutation in skeletal muscle ryanodine receptor calcium release channels that can release IL-6 when activated leading to excessive muscular contraction. Proinflammatory cytokine IL-6, dantrolene may block IL-6 release which results in its therapeutic effect in the treatment of MH. IL-6 has been used to predict deterioration from COVID-19. Dantrolene in this sense has been proposed as a potential therapeutic agent against COVID-19, inhibiting intracellular calcium influx thus preventing the pathological feedback of viral entry into cells via endocytosis, as this is a calcium dependent process. Given the possible link between IL-6 release, calcium and MH, SARS-CoV-2 viral entry into cells may place patients at higher risk of MH. Patients with COVID-19 may be at higher risk of MH, even in rare agents such as non-depolarizing agents as seen in this case. Awareness of this potentially increased complication from these agents in those patients with COVID-19 is key as we continue in the ongoing global pandemic. CONCLUSIONS: Given the possible link between IL-6 release, calcium and MH, SARS-CoV-2 viral entry into cells may place patients at higher risk of MH. Patients with COVID-19 may be at higher risk of malignant hyperthermia, even in rare agents such as non-depolarizing agents as seen in this case. Awareness of this potentially increased complication from these agents in those patients with COVID-19 is key as we continue in the ongoing global pandemic. Reference #1: Sathyanarayanan SP, Hamza M, Hamid K, Groskreutz D. Cisatracurium-Associated Malignant Hyperthermia During Severe Sars-CoV-2 Infection. Am J Ther. 2021 Aug 10;28(5):e590-e591. doi: 10.1097/MJT.0000000000001437. PMID: 34387563;PMCID: PMC8415506. Reference #2: Chiba N, Matsuzaki M, Mawatari T, Mizuochi M, Sakurai A, Kinoshita K. Beneficial effects of dantrolene in the treatment of rhabdomyolysis as a potential late complication associated with COVID-19: a case report. Eur J Med Res. 2021 Feb 8;26(1):18. doi: 10.1186/s40001-021-00489-8. PMID: 33557936;PMCID: PMC7868892. Reference #3: Han H, Ma Q, Li C, Liu R, Zhao L, Wang W, Zhang P, Liu X, Gao G, Liu F, Jiang Y, Cheng X, Zhu C, Xia Y. Profiling serum cytokines in COVID-19 patients reveals IL-6 and IL-10 are disease severity predictors. Emerg Microbes Infect. 2020 Dec;9(1):1123-1130. doi: 10.1080/22221751.2020.1770129. PMID: 32475230;PMCID: PMC7473317. DISCLOSURES: No relevant relationships by Hira Bakhtiar No relevant relationships by Timothy DAmico no disclosure on file for Sarah Margolskee;No relevant relationships by Carlos Merino No relevant relationships by Joanna Moore

HETEROTOPIC OSSIFICATION AFTER COVID-19 INFECTION - CASE REPORT

Background/Aims Heterotopic ossification (HO) is the abnormal formation and deposition of mature lamellar bone within soft tissue, associated with trauma, surgery, neurologic injury and prolonged immobilisation. Several recent case reports have demonstrated this condition in COVID-19 patients requiring mechanical ventilation. Methods We present a case of heterotopic ossification in the shoulder after a long stay in intensive care unit (ICU) due to COVID-19 infection. Results A 55-year-old man with stable psoriatic arthritis on sulfasalazine was admitted to ICU for mechanical ventilation after contracting COVID-19 infection. After discharge from ICU, he began noticing increasing right shoulder pain with restricted movements of abduction, internal and external rotation. His serum alkaline phosphatase was moderately elevated. Despite physiotherapy and NSAIDs, there was slow improvement. Shoulder x-ray showed significant bony overgrowth around proximal humerus which was initially thought to be part of his psoriatic arthritis. It was confirmed at Rheumatology/Radiology MDT to be heterotopic ossification. A computed tomography of the right shoulder was requested to evaluate the extent of the condition and orthopaedic advice was sought. Conclusion There are many factors contributing to the development of heterotopic ossification including trauma, spinal cord injury, brain injury, hypoxia, prolonged immobilisation with limitation of joint movement and prolonged bed rest which cause alterations in calcium homeostasis, male sex and over 60 years of age. New onset joint pain and stiffness in patients who have recovered from COVID-19 especially those who had long ICU stay should be further investigated for this condition. Treatment includes analgesia and physiotherapy with potential surgical intervention.

COVID-19: the CaMKII-like system of S protein drives membrane fusion and induces syncytial multinucleated giant cells.

The SARS-CoV-2 S protein on the membrane of infected cells can promote receptor-dependent syncytia formation, relating to extensive tissue damage and lymphocyte elimination. In this case, it is challenging to obtain neutralizing antibodies and prevent them through antibodies effectively. Considering that, in the current study, structural domain search methods are adopted to analyze the SARS-CoV-2 S protein to find the fusion mechanism. The results show that after the EF-hand domain of S protein bound to calcium ions, S2 protein had CaMKII protein activities. Besides, the CaMKII_AD domain of S2 changed S2 conformation, facilitating the formation of HR1-HR2 six-helix bundles. Apart from that, the Ca2+-ATPase of S2 pumped calcium ions from the virus cytoplasm to help membrane fusion, while motor structures of S drove the CaATP_NAI and CaMKII_AD domains to extend to the outside and combined the viral membrane and the cell membrane, thus forming a calcium bridge. Furthermore, the phospholipid-flipping-ATPase released water, triggering lipid mixing and fusion and generating fusion pores. Then, motor structures promoted fusion pore extension, followed by the cytoplasmic contents of the virus being discharged into the cell cytoplasm. After that, the membrane of the virus slid onto the cell membrane along the flowing membrane on the gap of the three CaATP_NAI. At last, the HR1-HR2 hexamer would fall into the cytoplasm or stay on the cell membrane. Therefore, the CaMKII_like system of S protein facilitated membrane fusion for further inducing syncytial multinucleated giant cells.