Ascorbic Acid Infusion Blunts CD40L Upregulation in Patients Undergoing Coronary Stent: Ascorbic Acid, CD40L, and PCI

Oxidative Stress and Hyper-Inflammation as Major Drivers of Severe COVID-19 and Long COVID: Implications for the Benefit of High-Dose Intravenous Vitamin C

Oxidative stress is a pivotal point in the pathophysiology of COVID-19 and presumably also in Long-COVID. Inflammation and oxidative stress are mutually reinforcing each other, thus contributing to the systemic hyperinflammatory state and coagulopathy which are cardinal pathological mechanisms of severe stages. COVID-19 patients, like other critically ill patients e.g. with pneumonia, very often show severe deficiency of the antioxidant vitamin C. So far, it has not been investigated how long this deficiency lasts or whether patients with long COVID symptoms also suffer from deficiencies. A vitamin C deficit has serious pathological consequences because vitamin C is one of the most effective antioxidants, but also co-factor of many enzymatic processes that affect the immune and nervous system, blood circulation and energy metabolism. Because of its anti-oxidative, anti-inflammatory, endothelial-restoring, and immunomodulatory effects the supportive intravenous (iv) use of supraphysiological doses has been investigated so far in 12 controlled or observational studies with altogether 1578 inpatients with COVID-19. In these studies an improved oxygenation, a decrease in inflammatory markers and a faster recovery were observed. In addition, early treatment with iv high dose vitamin C seems to reduce the risks of severe courses of the disease such as pneumonia and also mortality. Persistent inflammation, thrombosis and a dysregulated immune response (auto-immune phenomena and/or persistent viral load) seem to be major contributors to Long-COVID. Oxidative stress and inflammation are involved in the development and progression of fatigue and neuro-psychiatric symptoms in various diseases by disrupting tissue (e.g. autoantibodies), blood flow (e.g. immune thrombosis) and neurotransmitter metabolism (e.g. excitotoxicity). In oncological diseases, other viral infections and autoimmune diseases, which are often associated with fatigue, cognitive disorders, pain and depression similar to Long-COVID, iv high dose vitamin C was shown to significantly relieve these symptoms. Supportive iv vitamin C in acute COVID-19 might therefore reduce the risk of severe courses and also the development of Long-COVID.

Vitamin C May Improve Left Ventricular Ejection Fraction: A Meta-Analysis

Background

Vitamin C deprivation can lead to fatigue, dyspnea, oedema and chest pain, which are also symptoms of heart failure (HF). In animal studies vitamin C has improved contractility and mechanical efficiency of the heart. Compared with healthy people, patients with HF have lower vitamin C levels, which are not explained by differences in dietary intake levels, and more severe HF seems to be associated with lower plasma vitamin C levels. This meta-analysis looks at the effect of vitamin C on left ventricular ejection fraction (LVEF).

Methods

We searched for trials reporting the effects of vitamin C on LVEF. We assessed the quality of the trials, and pooled selected trials using the inverse variance, fixed effect options. We used meta-regression to examine the association between the effect of vitamin C on LVEF level and the baseline LVEF level.

Results

We identified 15 trials, three of which were excluded from our meta-analysis. In six cardiac trials with 246 patients, vitamin C increased LVEF on average by 12.0% (95% CI 8.1–15.9%; P < 0.001). In six non-cardiac trials including 177 participants, vitamin C increased LVEF on average by 5.3% (95% CI 2.0–8.5%; P = 0.001). In meta-regression analysis we found that the effect of vitamin C was larger in trials with the lowest baseline LVEF levels with P = 0.001 for the test of slope. The meta-regression line crossed the null effect level at a baseline LVEF level close to 70%, with progressively greater benefit from vitamin C with lower LVEF levels. Some of the included trials had methodological limitations. In a sensitivity analysis including only the four most methodologically sound cardiac trials, the effect of vitamin C was not substantially changed.

Conclusions

In this meta-analysis, vitamin C increased LVEF in both cardiac and non-cardiac patients, with a strong negative association between the size of the vitamin C effect and the baseline LVEF. Further research on vitamin C and HF should be carried out, particularly in patients who have low LVEF together with low vitamin C intake or low plasma levels. Different dosages and different routes of administration should be compared.

Release of α-granule contents during platelet activation

Upon activation, platelets release a plethora of factors which help to mediate their dynamic functions in hemostasis, inflammation, wound healing, tumor metastasis and angiogenesis. The majority of these bioactive molecules are released from α-granules, which are unique to platelets, and contain an incredibly diverse repertoire of cargo including; integral membrane proteins, pro-coagulant molecules, chemokines, mitogenic, growth and angiogenic factors, adhesion proteins, and microbicidal proteins. Clinically, activation of circulating platelets has increasingly been associated with various disease states. Biomarkers indicating the level of platelet activation in patients can therefore be useful tools to evaluate risk factors to predict future complications and determine treatment strategies or evaluate antiplatelet therapy. The irreversible nature of α-granule secretion makes it ideally suited as a marker of platelet activation. This review outlines the release and contents of platelet α-granules, as well as the membrane bound, and soluble α-granule cargo proteins that can be used as biomarkers of platelet activation.

Joint Cardioprotective Effect of Vitamin C and Other Antioxidants against Reperfusion Injury in Patients with Acute Myocardial Infarction Undergoing Percutaneous Coronary Intervention

Percutaneous coronary intervention (PCI) has long remained the gold standard therapy to restore coronary blood flow after acute myocardial infarction (AMI). However, this procedure leads to the development of increased production of reactive oxygen species (ROS) that can exacerbate the damage caused by AMI, particularly during the reperfusion phase. Numerous attempts based on antioxidant treatments, aimed to reduce the oxidative injury of cardiac tissue, have failed in achieving an effective therapy for these patients. Among these studies, results derived from the use of vitamin C (Vit C) have been inconclusive so far, likely due to suboptimal study designs, misinterpretations, and the erroneous conclusions of clinical trials. Nevertheless, recent clinical trials have shown that the intravenous infusion of Vit C prior to PCI-reduced cardiac injury biomarkers, as well as inflammatory biomarkers and ROS production. In addition, improvements of functional parameters, such as left ventricular ejection fraction (LVEF) and telediastolic left ventricular volume, showed a trend but had an inconclusive association with Vit C. Therefore, it seems reasonable that these beneficial effects could be further enhanced by the association with other antioxidant agents. Indeed, the complexity and the multifactorial nature of the mechanism of injury occurring in AMI demands multitarget agents to reach an enhancement of the expected cardioprotection, a paradigm needing to be demonstrated. The present review provides data supporting the view that an intravenous infusion containing combined safe antioxidants could be a suitable strategy to reduce cardiac injury, thus improving the clinical outcome, life quality, and life expectancy of patients subjected to PCI following AMI.

Vitamin C for Cardiac Protection during Percutaneous Coronary Intervention: A Systematic Review of Randomized Controlled Trials

Percutaneous coronary intervention (PCI) is the preferred treatment for acute coronary syndrome (ACS) secondary to atherosclerotic coronary artery disease. This nonsurgical procedure is also used for selective patients with stable angina. Although the procedure is essential for restoring blood flow, reperfusion can increase oxidative stress as a side effect. We address whether intravenous infusion of vitamin C (VC) prior to PCI provides a benefit for cardioprotection. A total of eight randomized controlled trials (RCT) reported in the literature were selected from 371 publications through systematic literature searches in six electronic databases. The data of VC effect on cardiac injury biomarkers and cardiac function were extracted from these trials adding up to a total of 1185 patients. VC administration reduced cardiac injury as measured by troponin and CK-MB elevations, along with increased antioxidant reservoir, reduced reactive oxygen species (ROS) and decreased inflammatory markers. Improvement of the left ventricular ejection fraction (LVEF) and telediastolic left ventricular volume (TLVV) showed a trend but inconclusive association with VC. Intravenous infusion of VC before PCI may serve as an effective method for cardioprotection against reperfusion injury.

Vitamin C Intravenous Treatment In the Setting of Atrial Fibrillation Ablation: Results From the Randomized, Double-Blinded, Placebo-Controlled CITRIS-AF Pilot Study

Background

Catheter ablation is an effective treatment for atrial fibrillation (AF), but high levels of post‐procedure inflammation predict adverse clinical events. Ascorbic acid (AA) has shown promise in reducing inflammation but is untested in this population. We sought to test the feasibility, safety, and preliminary effects on inflammatory biomarkers in the CITRIS‐AF (Vitamin C Intravenous Treatment In the Setting of Atrial Fibrillation Ablation) pilot study.

Methods and Results

Patients scheduled to undergo AF ablation (N=20) were randomized 1:1 to double‐blinded treatment with AA (200 mg/kg divided over 24 hours) or placebo. C‐reactive protein and interleukin‐6 levels were obtained before the first infusion and repeated at 24 hours and 30 days. Pain levels within 24 hours and early recurrence of AF within 90 days were recorded. Median and interquartile range were aged 63 (56–70) years, 13 (65%) men, and 18 (90%) white. Baseline data were similar between the 2 groups except ejection fraction. Baseline C‐reactive protein levels were 2.56 (1.47–5.87) mg/L and similar between groups (P=0.48). Change in C‐reactive protein from baseline to 24 hours was +10.79 (+6.56–23.19) mg/L in the placebo group and +3.01 (+0.40–5.43) mg/L in the AA group (P=0.02). Conversely, change in interleukin‐6 was numerically higher in the AA group, though not statistically significant (P=0.32). One patient in each arm developed pericarditis; no adverse events related to the infusions were seen. There were no significant differences between aggregated post‐procedure pain levels within 24 hours or early recurrence of AF (both P>0.05).

Conclusions

High‐dose AA is safe and well tolerated at the time of AF ablation and may be associated with a blunted rise in C‐reactive protein, although consistent findings were not seen in interleukin‐6 levels. Further studies are needed to validate these findings and explore the potential benefit in improving clinically relevant outcomes.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT03148236.

Effects and Mechanisms of Vitamin C Post-Conditioning on Platelet Activation after Hypoxia/Reoxygenation

Background

Platelet activation occurs upon ischemia/reperfusion and is related to the generation of reactive oxygen species (ROS) during this process. Vitamin C (VC) is a powerful antioxidant. VC scavenges ROS, reduces platelet activation, and attenuates reperfusion injury. However, the effects of VC on platelets undergoing hypoxia/reoxygenation (H/R) remain unclear.

Objectives

Herein, we evaluated the effects of VC on platelets in vitro following H/R and the related mechanisms.

Method

Fresh platelets were collected from 67 volunteers at the Blood Center of Hebei Province. Platelets were diluted with saline to a concentration of 2.00 × 10¹¹/L. Aggregation and the curve slope were evaluated within 4 h with a whole-blood impedance analyzer. To determine the optimal experimental time, platelets were treated with hypoxia or reoxygenation for different times, and impedance aggregometry was carried out by measuring changes in electrical impedance induced by arachidonic acid (0.5 mM) and adenosine diphosphate (10 µM), thereby establishing the H/R model. Three antioxidants (VC, melatonin, and probucol) were used to treat platelets after H/R, and impedance aggregometry was used to determine their effects on platelet aggregation. The influence of VC on apoptosis-related indicators was detected. ROS and the mitochondrial membrane potential were observed by inverted fluorescence microscopy and flow cytometry, respectively. Related protein levels were detected by Western blotting.

Results

ROS scavengers inhibited platelet activation and aggregation in a concentration-dependent manner. VC post-conditioning scavenged ROS, downregulated cytochrome C, Bax, and caspase-9 proteins, and upregulated Bcl-2 protein. These effects collectively blocked platelet apoptosis and inhibited platelet aggregation.

Conclusions

VC inhibited platelet aggregation by blocking apoptosis. Thus, VC may have applications in the treatment of platelet-related diseases.

Vitamin C Can Shorten the Length of Stay in the ICU: A Meta-Analysis

A number of controlled trials have previously found that in some contexts, vitamin C can have beneficial effects on blood pressure, infections, bronchoconstriction, atrial fibrillation, and acute kidney injury. However, the practical significance of these effects is not clear. The purpose of this meta-analysis was to evaluate whether vitamin C has an effect on the practical outcomes: length of stay in the intensive care unit (ICU) and duration of mechanical ventilation. We identified 18 relevant controlled trials with a total of 2004 patients, 13 of which investigated patients undergoing elective cardiac surgery. We carried out the meta-analysis using the inverse variance, fixed effect options, using the ratio of means scale. In 12 trials with 1766 patients, vitamin C reduced the length of ICU stay on average by 7.8% (95% CI: 4.2% to 11.2%; p = 0.00003). In six trials, orally administered vitamin C in doses of 1⁻3 g/day (weighted mean 2.0 g/day) reduced the length of ICU stay by 8.6% (p = 0.003). In three trials in which patients needed mechanical ventilation for over 24 hours, vitamin C shortened the duration of mechanical ventilation by 18.2% (95% CI 7.7% to 27%; p = 0.001). Given the insignificant cost of vitamin C, even an 8% reduction in ICU stay is worth exploring. The effects of vitamin C on ICU patients should be investigated in more detail.

Antioxidants in Translational Medicine

SIGNIFICANCE

It is generally accepted that reactive oxygen species (ROS) scavenging molecules or antioxidants exert health-promoting effects and thus their consumption as food additives and nutraceuticals has been greatly encouraged. Antioxidants may be beneficial in situations of subclinical deficiency and increased demand or acutely upon high-dose infusion. However, to date, there is little clinical evidence for the long-term benefit of most antioxidants. Alarmingly, recent evidence points even to health risks, in particular for supplements of lipophilic antioxidants.

RECENT ADVANCES

The biological impact of ROS depends not only on their quantities but also on their chemical nature, (sub)cellular and tissue location, and the rates of their formation and degradation. Moreover, ROS serve important physiological functions; thus, inappropriate removal of ROS may cause paradoxical reductive stress and thereby induce or promote disease.

CRITICAL ISSUES

Any recommendation on antioxidants must be based on solid clinical evidence and patient-relevant outcomes rather than surrogate parameters.

FUTURE DIRECTIONS

Such evidence-based use may include site-directed application, time-limited high dosing, (functional) pharmacological repair of oxidized biomolecules, and triggers of endogenous antioxidant response systems. Ideally, these approaches need guidance by patient stratification through predictive biomarkers and possibly imaging modalities.

Delayed sudden radial artery rupture after left transradial coronary catheterization: a case report

Local complications at the radial access site are not frequent, hence its large diffusion as the preferred access route for endovascular procedures. However, in a time of fast widespreading, better comprehension of all potential complications becomes critical to facilitate their early recognition and the most appropriate treatment. In this case report, we present for the first time a case of sudden massive bleeding at the left wrist, due to spontaneous gross rupture of the left radial artery bleeding 15 days after an endovascular procedure through a left radial arterial access. The patient had been readmitted to the hospital after evidence of local infection at the left wrist with loss of substance. The radial artery was patent with no evidence of pseudoaneurysm. After sudden radial artery rupture, with massive bleeding and suspicion that the local infection could have reached the arterial wall, surgical hemostasis with artery ligation was obtained. Healing of the large wound was then efficiently speeded up using a negative pressure wound therapy. This is the first case of macroscopic radial artery rupture associated with local wrist infection after arterial catheterization. After prompt surgical hemostasis, negative pressure wound therapy was very helpful in favoring healing of the large and deep wound.

Vitamin C supplementation in the critically ill patient

PURPOSE OF REVIEW

Vitamin C is not only an essential nutrient involved in many anabolic pathways, but also an important player of the endogenous antioxidant defense. Low plasma levels are very common in critical care patients and may reflect severe deficiency states.

RECENT FINDINGS

Vitamin C scavenges reactive oxygen species such as superoxide and peroxynitrite in plasma and cells (preventing damage to proteins, lipids and DNA), prevents occludin dephosphorylation and loosening of the tight junctions. Ascorbate improves microcirculatory flow impairment by inhibiting tumor-necrosis-factor-induced intracellular adhesion molecule expression, which triggers leukocyte stickiness and slugging. Clinical trials in sepsis, trauma and major burns testing high-dose vitamin C show clinical benefit. Restoration of normal plasma levels in inflammatory patients requires the administration of 3 g/day for several days, which is 30 times the daily recommended dose.

SUMMARY

The recent research on the modulation of oxidative stress and endothelial protection offer interesting therapeutic perspectives, based on the biochemical evidence, with limited or even absent side-effects.

The effect of intravenous vitamin C infusion on periprocedural myocardial injury for patients undergoing elective percutaneous coronary intervention

BACKGROUND

This small study has determined the effect of vitamin C on myocardial reperfusion in patients undergoing elective percutaneous coronary intervention (PCI). This study was to explore whether antioxidant vitamin C infusion before the procedure is able to affect the incidence of periprocedural myocardial injury (PMI) in patients undergoing PCI.

METHODS

In this prospective single-centre randomized study, 532 patients were randomized into 2 groups: the vitamin C group, which received a 3-g vitamin C infusion within 6 hours before PCI, and a control group, which received normal saline. The primary end point was the troponin I-defined PMI, and the second end point was the creatine kinase (CK)-MB-defined PMI. Separate analyses using both end points were performed. PMI was defined as an elevation of cardiac biomarker values (CK-MB or troponin I) > 5 times the upper limit of normal (ULN), alone or associated with chest pain or ST-segment or T-wave changes.

RESULTS

After PCI, the incidence of PMI was reduced, whether defined by troponin or by CK-MB, compared with the control group (troponin I, 10.9% vs 18.4%; P = 0.016; CK-MB, 4.2% vs 8.6%; P = 0.035). Logistic multivariate analysis showed that preprocedure use of vitamin C is an independent predictor of PMI either defined by troponin I (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.33-0.97; P = 0.037) or by CK-MB (OR, 0.37; 95% CI, 0.14-0.99; P = 0.048).

CONCLUSIONS

In patients undergoing elective PCI, preprocedure intravenous treatment with vitamin C is associated with less myocardial injury.

Platelet NOX, a novel target for anti-thrombotic treatment

There is a growing body of evidence to suggest that reactive oxidant species (ROS) including O2-, OH- or H2O2 act as second messengers to activate platelets via 1) calcium mobilisation, 2) nitric oxide (NO) inactivation, and 3) interaction with arachidonic to give formation of isoprostanes. Among the enzymes generating ROS formation NOX2, the catalytic core of NADPH oxidase (NOX), plays a prominent role as shown by the almost absent ROS production by platelets taken from patients with hereditary deficiency of NOX2. Experimental and clinical studies provided evidence that NOX2 is implicated in platelet activation. Thus, impaired platelet activation has been detected in patients with NOX2 hereditary deficiency. Similarly, normal platelets added with NOX2 specific inhibitors disclosed impaired platelet activation along with ROS down-regulation. Accordingly, animals prone to atherosclerosis treated with apocynin, a NOX inhibitor, showed reduced platelet adhesion and atherosclerotic plaque. Furthermore, a significant association between NOX2 up-regulation and platelet activation has been detected in patients at athero-thrombotic risk, but a cause-effect relationship needs to be established. These findings may represent a rationale to plan interventional trials with NOX inhibitors to establish if blocking NOX2 or other NOX isoforms may represent a novel anti-platelet approach.

Biomarkers of platelet activation in acute coronary syndromes

The most convincing evidence for the participation of platelets in arterial thrombosis in humans comes from studies of platelet activation in patients with acute coronary syndromes (ACS) and from trials of antiplatelet drugs. Both strongly support the concept that repeated episodes of platelet activation over the thrombogenic surface of a vulnerable plaque may contribute to the risk of death from coronary causes. However, the relation of in vivo platelet activation and adverse clinical events to results of platelet function tests remains largely unknown. A valuable marker of in vivo platelet activation should be specific, unaltered by pre-analytical artefacts and reproducibly measured by easily performed methods. This article describes current biomarkers of platelet activation in ACS, reviews their advantages and disadvantages, discusses their potential pitfalls, and demonstrates emerging data supporting the positive clinical implications of monitoring in vivo platelet activation in the setting of ACS.

Effect of L-carnitine on oxidative stress and platelet activation after major surgery

BACKGROUND

The surgical/anesthesia trauma is associated with an increased production of reactive oxygen species (ROS). This enhanced oxidative stress leads to cell damage resulting in various complications such as sepsis, myocardial injury and increased mortality. The aim of this study was to investigate the role of antioxidant treatment with l-carnitine in oxidative stress and platelet activation in patients undergoing major abdominal surgery.

METHODS

Forty patients scheduled for abdominal surgery were randomly allocated to l-carnitine, administered with a rapid infusion (0.05 g/kg) diluted in 250 ml of saline solution, vs. placebo treatment just before the surgical intervention. At baseline and after treatment, oxidative stress was evaluated by detection of circulating levels of soluble NOX2-derived peptide (sNOX2-dp), a marker of NADPH oxidase activation, and by analyzing platelet ROS formation. Platelet activation was studied by dosing sCD40L.

RESULTS

We observed an increase of soluble sNOX2-dp, sCD40L and ROS production in the placebo group compared with the baseline after the surgical intervention. Conversely, in the l-carnitine-treated group, sNOX2-dp, sCD40L and ROS production did not significantly differ from the baseline. A linear correlation analysis showed that Δ of ROS correlated with Δ of sNOX2 (R(s) =0.817; P<0.001) and Δ of sCD40L (R(s) =0.780; P<0.001). Multiple linear regression analysis showed that the only independent predictive variable associated with Δ of ROS was Δ of serum NOX2 levels (SE=0.05; standardized coefficient β=1.075; P<0.001).

CONCLUSION

Our findings suggest that l-carnitine could be helpful in modulating oxidative stress and platelet activation during major abdominal surgery-dependent oxidative damage.