Scurvy: historically a plague of the sailor that remains a consideration in the modern intensive care unit

Abrupt termination of vitamin C from ICU patients may increase mortality: secondary analysis of the LOVIT trial

BACKGROUND

The LOVIT trial examined the effect of vitamin C on sepsis patients, and concluded that in adults with sepsis receiving vasopressor therapy in the ICU, those who received 4-day intravenous vitamin C had a higher risk of death or persistent organ dysfunction at 28 days than those who received placebo. The aim of this study was to determine whether the abrupt termination of vitamin C administration could explain the increased mortality in the vitamin C group.

METHODS

We used Cox regression with two time periods to model the distribution of deaths over the first 11 days in the LOVIT trial.

RESULTS

Compared with a uniform difference between vitamin C and placebo groups over the 11-day follow-up period, addition of a separate vitamin C effect starting from day 5 improved the fit of the Cox model (p = 0.026). There was no difference in mortality between the groups during the 4-day vitamin C administration with RR = 0.97 (95% CI: 0.65-1.44). During the week after the sudden termination of vitamin C, there were 57 deaths in the vitamin C group, but only 32 deaths in the placebo group, with RR = 1.9 (95% CI: 1.2-2.9; p = 0.004).

CONCLUSION

The increased mortality in the vitamin C group in the LOVIT trial is not explained by ongoing vitamin C administration, but by the abrupt termination of vitamin C. The LOVIT trial findings should not be interpreted as evidence against vitamin C therapy for critically ill patients.

A novel nonenzymatic ascorbic acid electrochemical sensor based on gold nanoparticals-chicken egg white-copper phosphate-graphene oxide hybrid nanoflowers

Au-CEW-Cu₃(PO₄)₂-GO nanoflowers (HNFs), which were assembled of gold nanoparticals (Au NPs), chicken egg white (CEW), copper phosphate (Cu₃(PO₄)₂) and graphene oxide (GO) together to form a flower-like organic/inorganic hybrid nanocomposite, were synthesized through a simple and gentle one-pot co-precipitation method. The prepared samples were well characterized by scanning electron microscope, transmission electron microscope, energy dispersive x-ray spectrometer, x-ray diffraction and Raman spectrometer. The prepared Au-CEW-Cu₃(PO₄)₂-GO HNFs was used to modify glassy carbon electrode to fabricate an electrochemical sensor for detection of ascorbic acid (AA). The electrochemical test results show that the linear range of the developed sensor is 8-300μM and the detection limit is 2.67μM (S/N = 3). While this sensor displays high sensitivity of 6.01 × 10^-3μAμM^-1cm^-2and low detection potential of 35 mV due to the combination of the high conductivity of Au NPs, the larger specific surface area of GO and the intrinsic electrocatalytic activity of CEW-Cu₃(PO₄)₂HNFs. Moreover, the Au-CEW-Cu₃(PO₄)₂-GO HNFs-based sensor was successfully developed for application in electrochemical detection of AA in vitamin C tablets.

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.

Juvenile scurvy from Late Medieval Knin, Croatia

In this study, we examine the scurvy associated skeletal lesions among juveniles from the late Medieval site Uzdolje-Grablje in Croatia. The study aims to establish a demographic pattern of scurvy using existing diagnostic criteria. The sample consists of 16 well-preserved and fairly complete juveniles, excavated from a cemetery dating to 1420-1920. Skeletal remains were analyzed macroscopically for signs of porosity and new bone formation. Scurvy is diagnosed using the "Ortner criteria" of cranial and postcranial lesions. Depending on the location of the lesions, individuals were diagnosed with either scurvy or possible scurvy. Half of the individuals in our sample are diagnosed with scurvy, with additional 25% being diagnosed with possible scurvy. Along with porotic lesions, all individuals diagnosed with scurvy/possible scurvy showed new bone formation on at least one skeletal element. The occurrence of lesions associated with scurvy in our sample is unusually high. Instead of focusing solely on diet and insufficient intake of the vitamin C, a more likely explanation lies in the synergy between diet, exposure to infections, and the environment.

The role of vitamin C in the treatment of pain: new insights

The vitamin C deficiency disease scurvy is characterised by musculoskeletal pain and recent epidemiological evidence has indicated an association between suboptimal vitamin C status and spinal pain. Furthermore, accumulating evidence indicates that vitamin C administration can exhibit analgesic properties in some clinical conditions. The prevalence of hypovitaminosis C and vitamin C deficiency is high in various patient groups, such as surgical/trauma, infectious diseases and cancer patients. A number of recent clinical studies have shown that vitamin C administration to patients with chronic regional pain syndrome decreases their symptoms. Acute herpetic and post-herpetic neuralgia is also diminished with high dose vitamin C administration. Furthermore, cancer-related pain is decreased with high dose vitamin C, contributing to enhanced patient quality of life. A number of mechanisms have been proposed for vitamin C’s analgesic properties. Herein we propose a novel analgesic mechanism for vitamin C; as a cofactor for the biosynthesis of amidated opioid peptides. It is well established that vitamin C participates in the amidation of peptides, through acting as a cofactor for peptidyl-glycine α-amidating monooxygenase, the only enzyme known to amidate the carboxy terminal residue of neuropeptides and peptide hormones. Support for our proposed mechanism comes from studies which show a decreased requirement for opioid analgesics in surgical and cancer patients administered high dose vitamin C. Overall, vitamin C appears to be a safe and effective adjunctive therapy for acute and chronic pain relief in specific patient groups.

Vitamin C and Infections

In the early literature, vitamin C deficiency was associated with pneumonia. After its identification, a number of studies investigated the effects of vitamin C on diverse infections. A total of 148 animal studies indicated that vitamin C may alleviate or prevent infections caused by bacteria, viruses, and protozoa. The most extensively studied human infection is the common cold. Vitamin C administration does not decrease the average incidence of colds in the general population, yet it halved the number of colds in physically active people. Regularly administered vitamin C has shortened the duration of colds, indicating a biological effect. However, the role of vitamin C in common cold treatment is unclear. Two controlled trials found a statistically significant dose-response, for the duration of common cold symptoms, with up to 6-8 g/day of vitamin C. Thus, the negative findings of some therapeutic common cold studies might be explained by the low doses of 3-4 g/day of vitamin C. Three controlled trials found that vitamin C prevented pneumonia. Two controlled trials found a treatment benefit of vitamin C for pneumonia patients. One controlled trial reported treatment benefits for tetanus patients. The effects of vitamin C against infections should be investigated further.

Effect of high-dose Ascorbic acid on vasopressor's requirement in septic shock

Objective:

Effects of ascorbic acid on hemodynamic parameters of septic shock were evaluated in nonsurgical critically ill patients in limited previous studies. In this study, the effect of high-dose ascorbic acid on vasopressor drug requirement was evaluated in surgical critically ill patients with septic shock.

Methods:

Patients with septic shock who required a vasopressor drug to maintain mean arterial pressure >65 mmHg were assigned to receive either 25 mg/kg intravenous ascorbic acid every 6 h or matching placebo for 72 h. Vasopressor dose and duration were considered as the primary outcomes. Duration of Intensive Care Unit (ICU) stay and 28-day mortality has been defined as secondary outcomes.

Findings:

During the study period, 28 patients (14 in each group) completed the trial. Mean dose of norepinephrine during the study period (7.44 ± 3.65 vs. 13.79 ± 6.48 mcg/min, P = 0.004) and duration of norepinephrine administration (49.64 ± 25.67 vs. 71.57 ± 1.60 h, P = 0.007) were significantly lower in the ascorbic acid than the placebo group. No statistically significant difference was detected between the groups regarding the length of ICU stay. However, 28-day mortality was significantly lower in the ascorbic acid than the placebo group (14.28% vs. 64.28%, respectively; P = 0.009).

Conclusion:

High-dose ascorbic acid may be considered as an effective and safe adjuvant therapy in surgical critically ill patients with septic shock. The most effective dose of ascorbic acid and the best time for its administration should be determined in future studies.

Ascorbate-dependent vasopressor synthesis: a rationale for vitamin C administration in severe sepsis and septic shock?

Severe systemic inflammatory response to infection results in severe sepsis and septic shock, which are the leading causes of death in critically ill patients. Septic shock is characterised by refractory hypotension and is typically managed by fluid resuscitation and administration of catecholamine vasopressors such as norepinephrine. Vasopressin can also be administered to raise mean arterial pressure or decrease the norepinephrine dose. Endogenous norepinephrine and vasopressin are synthesised by the copper-containing enzymes dopamine β-hydroxylase and peptidylglycine α-amidating monooxygenase, respectively. Both of these enzymes require ascorbate as a cofactor for optimal activity. Patients with severe sepsis present with hypovitaminosis C, and pre-clinical and clinical studies have indicated that administration of high-dose ascorbate decreases the levels of pro-inflammatory biomarkers, attenuates organ dysfunction and improves haemodynamic parameters. It is conceivable that administration of ascorbate to septic patients with hypovitaminosis C could improve endogenous vasopressor synthesis and thus ameliorate the requirement for exogenously administered vasopressors. Ascorbate-dependent vasopressor synthesis represents a currently underexplored biochemical mechanism by which ascorbate could act as an adjuvant therapy for severe sepsis and septic shock.

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.

Vitamin C for preventing and treating pneumonia

BACKGROUND

Pneumonia is one of the most common serious infections, causing two million deaths annually among young children in low-income countries. In high-income countries pneumonia is most significantly a problem of the elderly.

OBJECTIVES

To assess the prophylactic and therapeutic effects of vitamin C on pneumonia.

SEARCH METHODS

We searched CENTRAL 2013, Issue 3, MEDLINE (1950 to March week 4, 2013), EMBASE (1974 to April 2013) and Web of Science (1955 to April 2013).

SELECTION CRITERIA

To assess the therapeutic effects of vitamin C, we selected placebo-controlled trials. To assess prophylactic effects, we selected controlled trials with or without a placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently read the trial reports and extracted data.

MAIN RESULTS

We identified three prophylactic trials which recorded 37 cases of community-acquired pneumonia in 2335 people. Only one was satisfactorily randomised, double-blind and placebo-controlled. Two trials examined military recruits and the third studied boys from "lower wage-earning classes" attending a boarding school in the UK during World War II. Each of these three trials found a statistically significant (80% or greater) reduction in pneumonia incidence in the vitamin C group. We identified two therapeutic trials involving 197 community-acquired pneumonia patients. Only one was satisfactorily randomised, double-blind and placebo-controlled. That trial studied elderly patients in the UK and found lower mortality and reduced severity in the vitamin C group; however, the benefit was restricted to the most ill patients. The other therapeutic trial studied adults with a wide age range in the former Soviet Union and found a dose-dependent reduction in the duration of pneumonia with two vitamin C doses. We identified one prophylactic trial recording 13 cases of hospital-acquired pneumonia in 37 severely burned patients; one-day administration of vitamin C had no effect on pneumonia incidence. The identified studies are clinically heterogeneous which limits their comparability. The included studies did not find adverse effects of vitamin C.

AUTHORS' CONCLUSIONS

The prophylactic use of vitamin C to prevent pneumonia should be further investigated in populations who have a high incidence of pneumonia, especially if dietary vitamin C intake is low. Similarly, the therapeutic effects of vitamin C should be studied, especially in patients with low plasma vitamin C levels. The current evidence is too weak to advocate prophylactic use of vitamin C to prevent pneumonia in the general population. Nevertheless, therapeutic vitamin C supplementation may be reasonable for pneumonia patients who have low vitamin C plasma levels because its cost and risks are low.

Vitamin C deficiency in an anticoagulated patient

A 64-year-old woman presented with a hemorrhagic perifollicular rash on her legs while taking warfarin. After biopsy, vitamin C deficiency was suggested as the diagnosis, which ascorbic acid assays later confirmed. Clinical resolution of the rash followed supplementation with vitamin C. Patients on a vitamin K limited diet may also be limiting their intake of vitamin C. Physicians should be aware of this possible correlation, and consider checking vitamin C levels in patients with a perifollicular hemorrhagic rash or other signs of vitamin C deficiency while on warfarin.