Therapeutic effects of high-dose vitamin C supplementation in patients with COVID-19: a meta-analysis

Role of intravenous vitamin C on outcomes in hospitalized patients with moderate or severe COVID-19: a real life data of Turkish patients

BACKGROUND

We aimed to examine the efficacy of intravenous vitamin C (IV-VC) in the treatment of hospitalized patients with moderate or severe COVID-19.

METHOD

We conducted a single-center and retrospective study including patients with COVID-19 diagnosis who were hospitalized. Patients were categorized into three groups as those who received low-dose (LDVC group, 2 g/day, n = 183) or high-dose IV-VC (HDVC group, 25 g/day, n = 41) and who did not receive IV-VC (control group, n = 46).

RESULTS

270 patients aged 19-97 years were enrolled. The median length of stay (LOS) was significantly high (9 days) in patients treated with high-dose VC when compared to patients treated with low-dose VC and control patients (6 vs 5 days, respectively). Need for intensive care unit (ICU) transfer was found to be significantly low in patients treated with low-dose VC (25.7%); contrarily, control patients had significantly higher rates of ICU transfer (67.4%), when compared to patients treated with high-dose VC (39%). Mortality of the LDVC group was significantly lower than that of the HDVC group (11.5 vs 29.3%). However, mortality rates were similar between the control and HDVC groups (21.7 vs 29.3%). According to the multivariate stepwise logistic regression mortality analysis, percent of change (∆%)-BUN was the most significant variable (p < 0.001), the second significant variable was ∆%-AST (p = 0.002), the third significant variable was respiratory distress (p = 0.002), and the fourth significant variable was the IV-VC groups (p = 0.017). The mortality risk of those in the LDVC group was 10.2 times low compared to the control group. Similarly, the risk of mortality in the HDVC group was 6.5 times lower than that of the control group.

CONCLUSION

Especially low and continious doses of IV-VC suggest fewer days of in-hospital LOS and survival benefit in hospitalized patients with moderate and severe COVID-19. Logistic regression analysis revealed that high-dose VC supplementation also had a mortality-reducing effect.

Ascorbyl palmitate ameliorates inflammatory diseases by inhibition of NLRP3 inflammasome

The aberrant activation of NLRP3 inflammasome contributes to pathogenesis of multiple inflammation-driven human diseases. However, the medications targeting NLRP3 inflammasome are not approved for clinic use to date. Here, we show that ascorbyl palmitate (AP), a lipophilic derivative of ascorbic acid (AA) and a safe food additive, is a potent inhibitor of NLRP3 inflammasome. Compared with AA, AP inhibited the activation of NLRP3 inflammasome with increased potency and specificity. Mechanistically, AP directly scavenged mitochondrial reactive oxygen species (mitoROS) by its antioxidant activity and blocked NLRP3-NEK7 interaction and NLRP3 inflammasome assembly. Moreover, AP showed more significant preventive effects than AA in LPS-induced systemic inflammation, dextran sulfate sodium (DSS)-induced colitis and experimental autoimmune encephalomyelitis (EAE). Thus, our results suggest that AP is a potential therapeutic combating NLRP3-driven diseases.

Precision nutrition to reset virus-induced human metabolic reprogramming and dysregulation (HMRD) in long-COVID

SARS-CoV-2, the etiological agent of COVID-19, is devoid of any metabolic capacity; therefore, it is critical for the viral pathogen to hijack host cellular metabolic machinery for its replication and propagation. This single-stranded RNA virus with a 29.9 kb genome encodes 14 open reading frames (ORFs) and initiates a plethora of virus-host protein-protein interactions in the human body. These extensive viral protein interactions with host-specific cellular targets could trigger severe human metabolic reprogramming/dysregulation (HMRD), a rewiring of sugar-, amino acid-, lipid-, and nucleotide-metabolism(s), as well as altered or impaired bioenergetics, immune dysfunction, and redox imbalance in the body. In the infectious process, the viral pathogen hijacks two major human receptors, angiotensin-converting enzyme (ACE)-2 and/or neuropilin (NRP)-1, for initial adhesion to cell surface; then utilizes two major host proteases, TMPRSS2 and/or furin, to gain cellular entry; and finally employs an endosomal enzyme, cathepsin L (CTSL) for fusogenic release of its viral genome. The virus-induced HMRD results in 5 possible infectious outcomes: asymptomatic, mild, moderate, severe to fatal episodes; while the symptomatic acute COVID-19 condition could manifest into 3 clinical phases: (i) hypoxia and hypoxemia (Warburg effect), (ii) hyperferritinemia ('cytokine storm'), and (iii) thrombocytosis (coagulopathy). The mean incubation period for COVID-19 onset was estimated to be 5.1 days, and most cases develop symptoms after 14 days. The mean viral clearance times were 24, 30, and 39 days for acute, severe, and ICU-admitted COVID-19 patients, respectively. However, about 25-70% of virus-free COVID-19 survivors continue to sustain virus-induced HMRD and exhibit a wide range of symptoms that are persistent, exacerbated, or new 'onset' clinical incidents, collectively termed as post-acute sequelae of COVID-19 (PASC) or long COVID. PASC patients experience several debilitating clinical condition(s) with >200 different and overlapping symptoms that may last for weeks to months. Chronic PASC is a cumulative outcome of at least 10 different HMRD-related pathophysiological mechanisms involving both virus-derived virulence factors and a multitude of innate host responses. Based on HMRD and virus-free clinical impairments of different human organs/systems, PASC patients can be categorized into 4 different clusters or sub-phenotypes: sub-phenotype-1 (33.8%) with cardiac and renal manifestations; sub-phenotype-2 (32.8%) with respiratory, sleep and anxiety disorders; sub-phenotype-3 (23.4%) with skeleto-muscular and nervous disorders; and sub-phenotype-4 (10.1%) with digestive and pulmonary dysfunctions. This narrative review elucidates the effects of viral hijack on host cellular machinery during SARS-CoV-2 infection, ensuing detrimental effect(s) of virus-induced HMRD on human metabolism, consequential symptomatic clinical implications, and damage to multiple organ systems; as well as chronic pathophysiological sequelae in virus-free PASC patients. We have also provided a few evidence-based, human randomized controlled trial (RCT)-tested, precision nutrients to reset HMRD for health recovery of PASC patients.