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R E S E A R C H Open Access
Phase I safety trial of intravenous ascorbic acid in
patients with severe sepsis
Alpha A Fowler III
1*
, Aamer A Syed
1
, Shelley Knowlson
2
, Robin Sculthorpe
3
, Don Farthing
4
, Christine DeWilde
1
,
Christine A Farthing
4
, Terri L Larus
4
, Erika Martin
5
, Donald F Brophy
5
, Seema Gupta
6
, Medical Respiratory Intensive
Care Unit Nursing
2
, Bernard J Fisher
1
and Ramesh Natarajan
1
Abstract
Background: Parenterally administered ascorbic acid modulates sepsis-induced inflammation and coagulation in
experimental animal models. The objective of this randomized, double-blind, placebo-controlled, phase I trial was to
determine the safety of intravenously infused ascorbic acid in patients with severe sepsis.
Methods: Twenty-four patients with severe sepsis in the medical intensive care unit were randomized 1:1:1 to receive
intravenous infusions every six hours for four days of ascorbic acid: Lo-AscA (50mg/kg/24h,n=8),orHi-AscA
(200 mg/kg/24 h, n = 8), or Placebo (5% dextrose/water, n = 8). The primary end points were ascorbic acid safety
and tolerability, assessed as treatment-related adverse-event frequency and severity. Patients were monitored
for worsened arterial hypotension, tachycardia, hypernatremia, and nausea or vomiting. In addition Sequential
Organ Failure Assessment (SOFA) scores and plasma levels of ascorbic acid, C-reactive protein, procalcitonin, and
thrombomodulin were monitored.
Results: Mean plasma ascorbic acid levels at entry for the entire cohort were 17.9± 2.4 μM (normal range 50-70 μM).
Ascorbic acid infusion rapidly and significantly increased plasma ascorbic acid levels. No adverse safety events were
observed in ascorbic acid-infused patients. Patients receiving ascorbic acid exhibited prompt reductions in SOFA
scores while placebo patients exhibited no such reduction. Ascorbic acid significantly reduced the proinflammatory
biomarkers C-reactive protein and procalcitonin. Unlike placebo patients, thrombomodulin in ascorbic acid infused
patients exhibited no significant rise, suggesting attenuation of vascular endothelial injury.
Conclusions: Intravenous ascorbic acid infusion was safe and well tolerated in this study and may positively impact
the extent of multiple organ failure and biomarkers of inflammation and endothelial injury.
Trial registration: ClinicalTrials.gov identifier NCT01434121.
Keywords: Ascorbic acid, Biological markers, Clinical trials phase I as topic, Multiple organ failure, Organ dysfunction
scores, Sepsis
Background
The incidence of sepsis and sepsis-associated organ failure
continues to rise in Intensive Care Units worldwide with
studies from multiple countries showing that organ failure
contributes cumulatively to patient mortality [1-3]. Patients
with severe sepsis suffer higher mortality rates compared
to patients with organ failure but no sepsis. Despite over
15,000 patients studied and over 1 billion dollars in study
costs effective sepsis therapy remains elusive [4,5]. Clinical
trials that have targeted mediators of inflammation or
coagulation such as atorvastatin [6] or activated protein
C [7] have not reduced septic mortality, suggesting that
single-target therapy fails to meet the challenges of
complex multicellular activation and interactions.
Recent studies suggest that ascorbic acid may attenuate
pathological responses in septic microvasculature. Armour
et al. and Wu et al. showed that ascorbic acid infusion im-
proved capillary blood flow, microvascular barrier function,
* Correspondence: afowler@mcvh-vcu.edu
1
Division of Pulmonary Disease and Critical Care Medicine, Department of
Internal Medicine, School of Medicine, Virginia Commonwealth University,
PO Box 980050, Richmond, VA 23298-0050, USA
Full list of author information is available at the end of the article
© 2014 Fowler et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication
waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise
stated.
Fowler et al. Journal of Translational Medicine 2014, 12:32
http://www.translational-medicine.com/content/12/1/32
and arteriolar responsiveness to vasoconstrictors in septic
animals [8,9]. Recently, we showed that parenterally infus-
ing ascorbic acid at a concentration of 200 mg/kg attenu-
ated vascular lung injury in septic mice by multiple
mechanisms, including attenuation of the proinflammatory
mediators, enhanced alveolar epithelial barrier function,
increased alveolar fluid clearance, and prevention of sepsis-
induced coagulopathy [10,11]. In addition, ascorbic acid
deficient mice were found to be more susceptible to
sepsis-induced multiple organ dysfunction and parenteral
infusion of ascorbic acid attenuated the injury (lung, kidney,
liver) [12].
Subnormal plasma ascorbic acid concentrations in septic
patients correlate inversely with the incidence of multiple
organ failure and directly with survival [13]. Ascorbic acid
depletion in sepsis results from: 1) ascorbic acid consump-
tion by reduction of plasma free iron, 2) ascorbic acid
consumption by the scavenging of aqueous free radicals,
and 3) by destruction of the oxidized form of ascorbic acid,
dehydroascorbic acid [14]. Dosing and bio-distribution data
in humans show that pharmacological concentrations of
ascorbic acid can only be attained following intravenous
administration [15]. Surprisingly, few studies in critically
ill patients infusing ascorbic acid have been performed.
Nathens and colleagues infused ascorbic acid at 1 gram
every 8 hours combined with oral vitamin E for 28 days in
594 surgically critically ill patients and found a significantly
lower incidence of acute lung injury and multiple organ
failure [16]. Tanaka et al. infused ascorbic acid continuously
at 66 mg/kg/hour for the first 24 hours in patients with
greater than 50% surface area burns and showed signifi-
cantly reduced burn capillary permeability [17]. A single
report (published as abstract only) of a clinical study of
large intravenous doses of ascorbic acid, and other antioxi-
dants (tocopherol, N-acetyl-cysteine, selenium), in patients
with established ARDS showed a 50% reduction in mortal-
ity [18]. Clinical protocols currently in use for hospitalized
septic patients fail to normalize ascorbic acid levels.
Ascorbic acid dosages utilized in this trial arose from our
preclinical work.
In the current trial, we sought to determine whether
intravenous ascorbic acid was safe to administer to critically
ill patients with severe sepsis and to determine if ascorbic
acid had an impact on organ failure and a priori selected
blood biomarkers. We measured C-reactive protein and
procalcitonin as systemic markers of inflammation while
choosing thrombomodulin as a marker of vascular injury
[19-21]. The work reported in this study has previously
been presented at the American Thoracic Society Inter-
national Meeting [22].
Methods
This study was approved by the VCU Institutional Review
Board (IRB). The IRB approval number assigned to this
trial was: HM12903. The trial was conducted under a
randomized double blind placebo-controlled format. A
multi-departmental data safety monitoring board oversaw
the trial.
Patient enrollment
Patients were screened and enrolled following admission
to the Medical Respiratory Intensive Care Unit in the VCU
Medical Center, Richmond, Virginia. Severe sepsis was
defined as: 1) Presence of a systemic inflammatory response:
(fever: >38°C or hypothermia: <36°C (core temp only),
heart rate > 90 beats/min, leukocytosis: >12,000 WBC/μL
or leukopenia: <4,000 WBC/μLor>10%bandforms)[23],
2) Suspected or proven infection,and3)Presence of sepsis-
induced organ dysfunction: Arterial hypoxemia (P
a
O
2
/
F
i
O
2
< 300), systolic blood pressure (SBP) < 90 mm Hg or
SBP decrease > 40 mm Hg unexplained by other causes,
Lactate > 2.5 mMol/L Urine output < 0.5 ml/kg/hour for
greater than two hours despite fluid resuscitation, platelet
count < 100,000, acutely developing coagulopathy (INR >
1.5), Bilirubin > 2 mg/dL. If these three criteria were met
within 48 hours of ICU admission, informed consent was
obtained from family members of patients deemed eligible
for the study. Study groups in this trial were 1) Placebo:5%
dextrose and water; 2) Low dose ascorbic acid (Lo-AscA):
50 mg/kg/24 hours; or 3) High dose ascorbic acid (Hi-
AscA): 200 mg/kg/24 hours. Ascorbic acid dosage was
divided into 4 equal doses and administered over 30 mi-
nutes every 6 hours for 96 hours in 50 ml of 5% dextrose
and water. Study drug infusion was initiated 2 to 4 hours
following informed consent and randomization.
The study blind was established and maintained by the
VCU Investigational Pharmacy Department where the
study drug was prepared, hooded, and dispensed. Subjects
were assigned to one of three dosing groups (0 mg/kg/day,
50 mg/kg/day, or 200 mg/kg/day) in a 1:1:1 ratio using
a randomization scheme generated by using Research
Randomizer [24]. Placebo or study drug was prepared in
50 mL polyvinyl chloride intravenous infusion bags (Viaflex,
Baxter Healthcare, Deerfield, IL). Ascorbic Acid Injection,
USP, (Bioniche Pharma, Lake Forest, IL) was used. Ascorbic
acid or placebo solutions were prepared in matching
volumes with amber shrouding for light protection and to
preserve the blind. Air was removed from IV bags for pro-
tection against ascorbic acid oxidation. Ascorbic acid was
stored at 2–8°C for up to 24 hours prior to use. Preliminary
experiments showed no oxidation under these brief stor-
age conditions.
Study data management
Collected data was managed using REDCap (Research
Electronic Data Capture), a secure, web-based data collec-
tion and storage tool hosted at VCU [25].
Fowler et al. Journal of Translational Medicine 2014, 12:32 Page 2 of 10
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Assessment of organ failure
Organ failure was assessed using the Sequential Organ
Failure Assessment (SOFA) score described by Vincent
and colleagues [26]. Scores were calculated at enrollment
and at 24, 48, 72, and 96 hours given the predictive value
of serial SOFA scores reported by Ferreira et al. [27].
Laboratory data and physiologic measures for calculating
SOFA scores were monitored daily and recorded into
REDCap. Data was normalized using the delta total SOFA
score (total maximum SOFA score at study entry minus
total maximum SOFA score over the 4-day study period)
[28,29].
Study drug infusion and safety monitoring
Vital signs were monitored every 5 minutes during infusion
and every 5 minutes for 45 minutes afterwards by bedside
Medical Respiratory Intensive Care Unit (MRICU) Nursing
and the investigative team. Patient safety in this Phase I
trial was paramount. Four objective indices were monitored
during and after ascorbic acid infusion: 1) Hypotension: De-
fined as a fall in mean arterial blood pressure of 20 mm Hg
during or following infusion, 2) Tachycardia: Defined as an
increase in heart rate of 20 beats per minute during or fol-
lowing infusion, 3) Hypernatremia: Standard of care utilizes
0.9% saline for volume resuscitation. L-Ascorbic acid prep-
aration used for this study presented a minor sodium load,
therefore a potential for hypernatremia to develop existed
and 4) Nausea or vomiting: were monitored both during
and after ascorbic acid administration by investigators and
by MRICU nursing staff. If one of the adverse events listed
above was observed, ICU nursing was equipped with bed-
side algorithms designed to manage the adverse event. If an
event was observed, drug infusion was halted. If the event
resolved, drug infusion was restarted at 50% of the original
infusion rate. If the event recurred, the patient was removed
from the study. If no adverse event was observed, patients
were infused for 4 days. Patients were then followed clinic-
ally for 28 days.
Blood samples
Whole venous blood was drawn into sterile Vacutainer®
tubes (Becton, Dickinson & Co., Franklin Lakes, NJ): serum
tube (BD 367812, red top, clot activator) and plasma tube
(lavender top, BD 367861, K2EDTA). Serum samples were
allowed to coagulate for 60 min at room temperature.
Plasma and serum were separated by centrifugation. An
aliquot of freshly isolated plasma was processed for ascorbic
acid analysis. Remaining plasma and serum were aliquoted
and frozen at −70°C until assayed.
Plasma ascorbic acid measurement
Plasma Ascorbic Acid Stability: Preliminary work optimized
conditions for stabilizing ascorbic acid in EDTA plasma
samples. Briefly, 0.4 ml of cold 20% trichloroacetic acid
(TCA) and 0.4 ml of cold 0.2% dithiothreitol (DTT)
were added to 0.2 ml of plasma, vortexed for 2 min, and
centrifuged (10,000 g, 10 min, 4°C). Supernatants were
aliquoted and frozen at −70°C for batch analysis. Quality
control samples consisted of normal plasma spiked with
ascorbic acid (100 & 1,000 μM), processed in the same
manner, and stored with patient samples. Plasma Ascorbic
Acid Concentrations: Plasma ascorbic acid levels were
quantified in all patients at enrollment then just prior to
administration of the 12, 24, 36, 48, 72, and 96 hour
ascorbic acid dosing. Concentrations were measured using
high pressure liquid chromatography (HPLC) with UV
detection. Chromatography was performed on an Onyx
MonolithicC18Column(100×4.6mm;Phenomenex,
Torrance, CA) with a mobile phase using a gradient buffer
(dipotassium phosphate), ion pairing reagent (tretrabutyl
amonium chloride), and acetonitrile at a flow rate 0.8 ml/
min. Detection was at 265 nm and ascorbic acid levels
quantified using peak area analysis and external stan-
dardization. Ascorbic acid standards (0–1,000 μM) were
freshly prepared and treated in the same way as the test
plasma samples.
Biomarkers
Biomarkers measured for this study were identified prior
to the start of the study. C-Reactive Protein (CRP):Ahigh
sensitivity C-reactive protein (hsCRP) assay was performed
in collaboration with Health Diagnostics Laboratories,
Richmond, Virginia using the Roche hsCRP kit (catalog #
11972855216) on a Roche automated chemistry analyzer.
Procalcitonin (PCT): Procalcitonin levels were quantified
using a sandwich ELISA kit according to manufacturer’s
instructions (RayBiotech, Inc., Norcross, GA). Thrombomo-
dulin (TM): Plasma levels were quantified using an enzyme-
linked immunosorbent assay kit (IMUBIND; American
Diagnostica Inc., Stamford, Connecticut, USA). Samples
were incubated in microwells precoated with a monoclo-
nal antibody specific for human thrombomodulin.
See Additional file 1 for description of methods utilized
for biomarker analysis.
Statistical analysis
All analyses in this study were pre-specified. Statistical
analysis was performed using SAS 9.3 and Graphpad
PRISM 6.0. The results are expressed as means ± SE. Dif-
ferences between and within groups were analyzed using
two-factor analysis of variance with Tukey’sstudentized
range test. Summary data is reported as mean ± SEM.
Statistical significance was confirmed at a p value of <0.05.
Organ dysfunction analysis was based on the evolution
(slopes) of the delta daily total SOFA score (change in
daily total SOFA score compared with day 0) over 4
study days by comparing the regression coefficients using
Student’s t-test [28,29].
Fowler et al. Journal of Translational Medicine 2014, 12:32 Page 3 of 10
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Results
Enrolled study patients
Over a one year period, 35 patients were screened and
26 patients were enrolled. Reasons for excluding the 9
patients are as follows: a) 3 patients had terminal cancer
and were not expected to survive for 24 hours; b) Informed
consent could not be obtained in two homeless septic
patients, and c) family members refused consent in 4
patients. Eight were enrolled in the placebo group, 8
enrolled in the Lo-AscA group, and 10 enrolled in the
Hi-AscA. One patient in the Hi-AscA group was with-
drawn by family members and transferred to another in-
stitution. One other Hi-AscA patient was withdrawn after
Hemophagocytic Syndrome plus sepsis was recognized.
These two patients are not included in the analysis. All
patients received full ICU standard of care support.
Table 1 shows the demographics of enrolled patients. The
APACHE II and SOFA scores between groups were statis-
tically identical. Table 2 indicates the underlying diagnosis
for patients entered into the trial, the organ system affected,
the source and identification of organisms in the patients,
and on day one of entry into the trial whether acute kidney
injury or respiratory failure was present. Secondary out-
comes (i.e., days on vasopressor, Ventilator days, ICU
length of stay and 28 day mortality) are now reported
in Additional file 2: Table S1. The cohort of patients in
this trial had a high incidence of respiratory failure.
Nineteen patients had ARDS at entry as defined by the
Berlin Definition with P
a
O
2
/F
i
O
2
(PF) ratios of less
than 300 and patchy airspace disease on chest imaging.
Five patients had PF ratios above 300. Of the group
with PF ratios above 300 only two were not intubated
for ventilatory support. One patient in the group with PF
ratios above 300 eventually fell below 300 and satisfied the
Berlin Definition of ARDS.
Safety of intravenous ascorbic acid
Safety of ascorbic acid infusion in critically ill patients was a
primary endpoint for this Phase I safety trial. During the
96-hour infusion period, no patients were withdrawn
due to study-related adverse events (i.e., hypotension,
tachycardia, hypernatremia, or nausea/vomiting). Infusions
were halted in one septic patient (Hi-AscA) following in-
fusion #14 (84 hours) for a ventricular arrhythmia later
determined by Cardiology consultants to be electrical
artifact. This patient is included in the analysis.
Plasma ascorbic acid levels
Plasma ascorbic acid levels in all septic patients at enroll-
ment were subnormal (i.e., hyposcorbic) at 17.9 ± 2.4 μM
(normal 50 –70 μM) and were not significantly different
at baseline (Figure 1). Ascorbic acid levels in the placebo
group fell from 20.2 (11–45) μM at entry to 15.6 (7–27)
μM on study day 4. Ascorbic acid levels increased 20-fold
in the low dose treatment group from 16.7 (14–28) μMat
baseline to 331 (110–806) μm on day 4. Ascorbic acid
levels increased dramatically in Hi-AscA patients from
17.0 (11–50) μM at baseline to 3,082 (1,592 - 5,722) μm
on day 4. Thus, ascorbic acid levels rose rapidly in the two
treatment groups and were significantly higher than pla-
cebo within twelve hours (Lo-AscA vs. placebo p < 0.005,
Hi-AscA vs. placebo p < 0.0005) remaining consistently
elevated for the 96-hour infusion period. Furthermore,
ascorbic acid levels in the Hi-AscA group were significantly
higher (p < 0.005) than the Lo-AscA group from the 12
hour point forward reaching millimolar concentrations.
These data confirm “hyposcorbic”levels present in un-
treated human sepsis and show that intermittent ascorbic
acid infusion every 6 hours produces sustained steady-state
plasma levels.
Impact of ascorbic acid infusion on organ failure
SOFA scores at enrollment were: Placebo –13.3 ± 2.9,
Lo-AscA –10.1 ± 2.0, and Hi-AscA 10.8 ± 4.4 and were
not significantly different across groups. The components
of the SOFA score are listed in Additional file 3: Table S2.
Following normalization of the daily SOFA scores, patients
treated with either dose of ascorbic acid exhibited de-
scending SOFA scores over the 4-day study period (p < 0.05,
slopes significantly non-zero). High dose ascorbic acid
patients exhibited significantly faster declines in the re-
gression slopes of delta daily total SOFA scores over time
compared to placebo (−0.043 vs. 0.003, p < 0.01) (Figure 2).
Placebo patients exhibited a gradual rise in SOFA scores.
Though the cohort size is limited, these data suggest that
ascorbic acid infusion significantly attenuates the systemic
organ injury associated with sepsis.
Impact of ascorbic acid infusion on biomarkers
Serum/plasma obtained from enrolled subjects were an-
alyzed for three biomarkers: C-reactive protein (CRP),
procalcitonin (PCT), and thrombomodulin (TM). CRP and
PCT were quantified as surrogates for inflammation while
TM was employed as a surrogate for endothelial injury. At
enrollment, biomarker levels across the three groups were
not significantly different. Serum CRP trended slowly down
over the 96 hour period in the placebo group. Patients
receiving ascorbic acid exhibited rapid reductions in
Table 1 Baseline demographic data of septic patients
treated or not treated with intravenous ascorbic acid
Treatment Gender Age APACHE II
score
a
SOFA
score
b
Placebo 4 male 4 female 54 –68 years 20.4 (15 –29) 13.3 ± 2.9
Lo-AscA 5 male 3 female 30 –70 years 20.4 (12 –23) 10.1 ± 2.0
Hi-AscA 4 male 4 female 49 –92 years 24.0 (12 –33) 10.8 ± 4.4
a
APACHE Acute Physiology and Chronic Health Evaluation, mean (range).
b
SOFA Sequential Organ Failure Assessment, mean ± SE.
Fowler et al. Journal of Translational Medicine 2014, 12:32 Page 4 of 10
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Table 2 Clinical data on patients with severe sepsis
Underlying conditions Source of sepsis Organism Renal failure? Respiratory failure?
Lung cancer Pneumonia Blood: E.coli, Strep bovis no yes
Resp: E.coli
Prodrome with nausea and
vomiting for 7 days
Pneumonia Blood: culture negative no yes
Urine: Legionella antigen positive
ETOH cirrhosis Spontaneous bacterial
peritonitis
Blood: culture negative no yes
Status/Post gastric bypass Urinary tract infection Blood: E. Coli no yes
Obstructive nephrolithiasis
pyelonephritis
Urinary tract infection Blood: E.Coli no yes
Urine: E.Coli
End stage renal disease Catheter sepsis Blood: MRSA yes (prior to admission) yes
Acute myelogenous
leukemia (relapse)
Portacath sepsis Blood: MRSA no yes
Urine: Enterobacter
Influenza Pneumonia with
coexistent Influenza A
Blood: Strep pneumonia no yes
Resp: Influenza A
Diabetes mellitus Infected diabetic foot
ulcer
Blood: Staph aureus no yes
Chronic kidney disease Body Fluid: Staph aureus
Gout Resp: MRSA
Head and neck cancer Pneumonia Blood: culture negative no yes
Resp: culture negative
Diabetes mellitus Pneumonia and colitis Blood: culture negative yes (dialysis required) yes
Congestive heart failure
Gastrointestinal hemorrhage Resp: MRSA
Cellulitis Pneumonia Blood: Group a strep. no no
Hypercholesterolemia Urinary tract infection
Multiple myeloma PneumoniaUrinary tract
infection
Blood: Gram positive cocci no yes
Urine: Proteus mirabilis
Non-Hodgkins lymphoma Pancreatitis Resp: Aspergillus fumigatus no yes
Bone marrow transplant Intra-abdominal sepsis Blood: Gram negative rods,
Gram positive cocci
no yes
Bowel perforation
Post allogeneic bone marrow
transplant
Pneumonia Blood: culture negative no yes
Chronic opiate use Aspiration pneumonia Blood: Strep. pneumonia no yes
Found obtunded Resp: Strep. pneumonia,
Candida glabrata
Diabetes mellitus Aspiration pneumonia Resp: Gram negative rods,
gram positive cocci
yes (prior to admission) yes
End stage renal disease
Chronic obstructive pulmonary
disease
Pneumonia Blood: culture negative no yes
Resp: Acinetobacter,
Stenotrophomonas maltiphilia
Toxic epidermal necrolysis Skin Blood: MRSA yes yes
Acute renal failure
Alcoholic cirrhosis Subacute bacterial
peritonitis
Blood: culture negative no no
Hepatorenal syndrome
Chronic obstructive pulmonary
disease
Pneumonia Blood: Gram positive rods no yes
Severe ankylosing spondylitis Urinary tract infection Blood: Klebsiella pneumonia no yes
Fowler et al. Journal of Translational Medicine 2014, 12:32 Page 5 of 10
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CRP levels achieving significantly lower levels when
compared to their own baseline and placebo by 24 hours
(Figure 3A, p < 0.05). PCT levels trended higher in placebo-
infused patients 24 hours following the onset of sepsis
though not reaching statistical significance. Serum PCT
levels in patients receiving high dose ascorbic acid declined,
becoming significantly lower than baseline by 48 hours
(Figure 3B, p < 0.05). PCT in patients receiving high dose
ascorbic acid continued to decline over the 96-hour period.
Plasma TM levels in patients randomized to placebo were
not different from the ascorbic acid groups at baseline.
Placebo patients began to trend upwards beyond 36 hours,
remaining elevated when compared to ascorbic acid treated
patients though the values were not statistically significant
(Figure 4). Importantly ascorbic acid treated patients did
not exhibit the upward trend in TM levels observed in
placebo-infused patients. These results suggest that as-
corbic acid infusion produces early reductions in pro-
inflammatory mediators in patients with severe sepsis.
The results further suggest that ascorbic acid infusion
attenuates the evolution of endothelial injury characteris-
tic of severe sepsis in humans.
Discussion
This phase I trial focused on the safety of administering
intravenous ascorbic acid to patients with severe sepsis.
The intravenous route of administration was chosen in
this trial in order to achieve high ascorbic acid plasma
levels. Padayatty and colleagues showed that high-level
ascorbic acid plasma concentrations could only be achieved
by intravenous administration [15]. Prior human studies
employing pharmacologic ascorbic acid dosing report no
adverse events. Nathens et al. administered 1 gram of as-
corbic acid every 8 hours for 28 days to surgically critically
ill patients with no ill effects [16]. Tanaka et al. adminis-
tered 66 mg/kg/hour for 24 hours to patients with 50%
Table 2 Clinical data on patients with severe sepsis (Continued)
Urine: Klebsiella pneumoniaSevere aortic stenosis
Hepatitis C cirrhosis Health care acquired
pneumonia
Blood: culture negative yes (dialysis required) yes
Urine: EnterococcusEsophageal varicies
Systemic mastocytosis Pneumonia Blood: culture negative no yes
Congestive heart failure Resp: Budding yeast with
pseudohyphae
Figure 1 Plasma ascorbic acid levels following intravenous
infusion of ascorbic acid. Plasma ascorbic acid levels were
subnormal at entry (<50 μM, dotted line). Ascorbic acid levels rose
rapidly in the two treatment groups and were significantly higher
than placebo within twelve hours (Lo-AscA vs. placebo p < 0.005,
Hi-AscA vs. placebo p < 0.0005) remaining consistently elevated for
96 hours. Ascorbic acid levels in the Hi-AscA group were significantly
higher than the Lo-AscA group from the 12 hour point forward.
These data show that an intermittent ascorbic acid infusion protocol
(every 6 hours) produces sustained steady state levels in patients
with severe sepsis. Placebo (О), Lo-AscA (▼), Hi-AscA (▲).
Figure 2 Effect of ascorbic acid infusion on Sequential Organ
Failure Assessment (SOFA) score (days 0–4). Daily mean SOFA
scores decreased over time with both doses of ascorbic acid infusion
(p <0.05 significantly non-zero) with the higher dose significantly less
than placebo (Hi-AscA vs. placebo p<0.01). Placebo (О), Lo-AscA (▼),
Hi-AscA (▲).
Fowler et al. Journal of Translational Medicine 2014, 12:32 Page 6 of 10
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surface area burns with no adverse events [17]. Hoffer
et al. intravenously administered up to 90 grams of ascorbic
acid 3 times weekly to patients with advanced malignancy
with no adverse events [30]. The dosing protocols we
chose for this trial arose out of our preclinical work.
No patient in the low or high dose ascorbic acid treat-
ment arms of this study suffered any identifiable adverse
event. As noted above, the one instance in which ascorbic
acid infusion was halted for a cardiac rhythm disturbance
was determined to be artifact by the Division of Cardiology.
Thus, a pharmacologic ascorbic acid treatment strategy in
critically ill patients with severe sepsis appears to be safe.
Prior studies show that patients with severe sepsis exhibit
significantly reduced plasma ascorbic acid levels upon
admission to intensive care [31]. The mean initial plasma
ascorbic acid level for all septic patients in this study was
17.9 ± 2.4 μM compared to normal human plasma levels
of 50 –70 μM (Figure 1). Prior studies [13,14,26], and the
current study show that subnormal plasma ascorbic acid
levels are a predictable feature in patients with severe
sepsis. Importantly, Placebo patients exhibited no change
in plasma ascorbic acid levels throughout the 4-day study
period despite receiving full ICU standard of care practice
for severe sepsis (Figure 1). Ascorbic acid depletion in
sepsis results from ascorbic acid consumption by the
reduction of plasma free iron, ascorbic acid consumption
by the scavenging of aqueous free radicals (peroxyl rad-
icals), and by the destruction of the oxidized form of
ascorbic acid dehydroascorbic acid [14]. Sepsis further
inhibits intracellular reduction of dehydroascorbic acid,
producing acute intracellular ascorbic acid depletion.
Sepsis-induced ascorbic aciddestructionpermitsun-
controlled oxidant activity which amplifies tissue injury
[14,32,33]. Ascorbic acid treated patients in this study ex-
hibited rapid and sustained increases in plasma ascorbic
acid levels using an intermittent every six hours adminis-
tration protocol (Figure 1).
SOFA scores are robust indicators of mortality during
critical illness. SOFA score increases during the first 48
hours of ICU care predict a mortality rate of at least 50%
[26]. In this study, the extent of organ failure accompanying
patients with severe sepsis was high with an average SOFA
score for all patients equal to 11.4 ± 3 confirming that
multiple organ failure was present at enrollment. Given
that the mean plasma ascorbic acid levels on admission
were subnormal (17.9 ± 2.4 μM), a mean initial SOFA
score of 11.4 ± 3 in patients with severe sepsis was not
Figure 3 Serum C-reactive protein (CRP) and procalcitonin
levels in septic placebo controls and ascorbic acid infused patients.
(A) Both the Lo-AscA and the Hi-AscA dosages produced rapid
reductions in serum CRP levels, becoming significantly lower than
placebo (*p < 0.05 vs placebo) as early as 24 hours. Ascorbic acid
infusion reduced CRP levels in both groups throughout the 4
studydays(#p<0.05vs0hr).CRPlevelsinplacebopatients
slowlyfelloverthecourseofthe4daystudyperiod.(B) Patients
in the Lo-AscA and Hi-AscA groups exhibited reduced serum PCT
levels beginning at 12 hours. Patients in the Hi-VitC group exhibited
further significant reduction in serum PCT between 36 to 48 hours
(#p < 0.05 vs 0 hr). Placebo patients exhibited a trend towards increased
PCT levels which declined starting at 72 hours post onset of sepsis.
Placebo (О), Lo-AscA (▼), Hi-AscA (▲).
Figure 4 Plasma thrombomodulin (TM) levels measured in
septic placebo controls and ascorbic acid infused patients.
Plasma TM levels measured in the ascorbic acid infused patients
exhibited no rise throughout the 4 days of study. Patients in the
placebo group showed a trend towards increased plasma TM levels
beginning at 36 hours, though it did not achieve statistical
significance. Placebo (О), Lo-AscA (▼), Hi-AscA (▲).
Fowler et al. Journal of Translational Medicine 2014, 12:32 Page 7 of 10
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surprising. This study is in agreement with other studies
which show that plasma ascorbic acid levels in severe
sepsis correlate inversely with the incidence of multiple
organ failure [13]. We showed that the addition of ascorbic
acid to standard of care practice (i.e., fluid resuscitation,
antibiotics, vasopressor medication) for patients with
severe sepsis significantly reduced organ injury. Ascorbic
acid treated patients exhibited prompt and sustained
reductions in SOFA scores during the 4-day treatment
regimen unlike placebo controls where SOFA scores slowly
increased over time. SOFA score reduction was most re-
markable in patients receiving the high dose ascorbic acid
infusion (Figure 2).
C-reactive protein (CRP) [19] and procalcitonin (PCT)
[20] levels are known to correlate with the overall extent
of infection and higher levels of both have both been
linked to higher incidences of organ injury and death in
the critically ill. CRP in circulation has a short half-life
of approximately 19 hours. Thus, the kinetics of CRP
make it a useful monitor for tracking the inflammatory
response produced by infection, and the response to
antibiotic treatment. Lobo et al. reported that patients
with CRP levels greater than 10 mg/dL at ICU admission
exhibited significantly higher rates of multiple organ fail-
ure as well as higher mortality rates [34]. A decrease in
CRP levels in Lobo’s study after 48 hours was associated
with a mortality rate of only 15.4%, while a persistently
high CRP level was associated with a mortality rate of
60.9%. Both low and high dose ascorbic acid infusion in
this trial promptly reduced serum CRP levels in septic
patients (Figure 3A). Thus, the findings in this study
support the findings of Lobo et al. with descending CRP
levels being associated with lower mortality rate and re-
duced levels or organ failure. Jensen and colleagues found
that high maximal procalcitonin levels were an early inde-
pendent predictor of all-cause mortality in a 90-day follow-
up period after intensive care unit admission [20]. Karlsson
and colleagues [21] showed that mortality in patients with
severe sepsis was lower in those patients in whom procalci-
tonin concentrations fell by more than 50% at 72 hours
with respect to initial values. Infusion of ascorbic acid into
patients with severe sepsis in this study reduced serum
procalcitonin levels by greater than 50% (Figure 3B).
Thrombomodulin is an endothelial cell bound molecule
that captures thrombin holding it adjacent to protein C
bound to its receptor (endothelial protein C receptor).
Elevated soluble TM in the circulation indicates endothelial
cell injury [35]. Lin et al. reported that increased TM levels
correlated with the extent of organ failure and mortality in
patients with sepsis [36]. In the current study, thrombo-
modulin levels in patients randomized to placebo began
to rise at approximately 36 hours into the study period,
indicating sepsis-induced endothelial injury (Figure 4).
Patients randomized to receive either dose of ascorbic acid
exhibited no subsequent rise in plasma thrombomodulin.
Though our patient numbers were small, these early results
suggestthatintravenousascorbic acid acts to attenuate the
proinflammatory state of sepsis and perhaps attenuates the
development of endothelial injury.
On the basis of this study and our prior preclinical
studies, we speculate as to the pleiotropic mechanisms by
which ascorbic acid would be beneficial in sepsis. Ascorbic
acid is rapidly taken up by endothelial cells in millimolar
quantities where it scavenges reactive oxygen species and
increases endothelial nitric oxide synthase-derived nitric
oxide by restoring tetrahydrobiopterin content, thus, in-
creasing bioavailable nitric oxide. As we and others have
shown in basic investigations [10,11,37], by inhibiting
NFκB activation, ascorbic acid could potentially attenu-
ate the “cytokine storm”that arises due to NFκBdriven
genes known to be activated in sepsis. Septic ascorbic
acid-deficient neutrophils fail to undergo normal apop-
tosis. Rather, they undergo necrosis thereby releasing
hydrolytic enzymes in tissue beds, thus contributing to
organ injury. We speculate that intravenous ascorbic
acid acts to restore neutrophil ascorbic acid levels. Re-
pletion of ascorbic acid in this way allows for normal
apoptosis, thus, preventing the release of organ dam-
aging hydrolytic enzymes. A multitude of biological
mechanisms are active in patients with sepsis and they
promote multiple organ injury and death.
Tens of thousands of lives are lost across the world an-
nually due to severe sepsis [1,38-40]. Multiple treatment
trials have failed to measurably improve outcomes. The
majority of trials have singly eliminated certain proinflam-
matory mediators which research has suggested promotes
tissue damage. The single mediator approach has largely
been unsuccessful. The results from this small phase I
safety trial suggest that administering ascorbic acid in
pharmacological dosages to critically ill patients with
sepsis is safe and that it may provide adjunctive therapy
in the treatment of severe sepsis. A larger phase II proof-
of-concept trial is needed.
Conclusions
This phase I trial shows that aggressive repletion of plasma
ascorbic acid levels in patients with severe sepsis is safe.
This early work in septic patients suggests that pharmaco-
logic ascorbic acid repletion reduces the extent of multiple
organ failure and attenuates circulating injury biomarker
levels.
Additional files
Additional file 1: Patient Flow Diagram. Flow diagram of the progress
through the phases of the safety trial (enrollment, allocation, follow-up,
and analysis).
Fowler et al. Journal of Translational Medicine 2014, 12:32 Page 8 of 10
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Additional file 2: Table S1. Secondary outcomes of septic patients
treated or not treated with intravenous ascorbic acid. Includes days on
vasopressor, ventilator free days, ICU length of stay, and 28-day mortality.
Additional file 3: Table S2: Components of the Sequential Organ Failure
Assessment (SOFA) scoring system. Describes the clinical parameters of the
scoring system.
Abbreviations
AscA: Ascorbic acid; CRP: C-reactive protein; PCT: Procalcitonin;
SOFA: Sequential organ failure assessment; TM: Thrombomodulin.
Competing interests
The authors declare that they have no competing interests.
Authors’contributions
AAF, RN, BJF, AAS: Hypothesis/delineation. AAF, AAS, DF, RS, SK, CD: Study
design. AAF, AAS, RN, BJF, DF, CAF, TLL, CD, SG, EM, DFB, MRICU Nursing:
Acquisition of data/analysis. AAF, RN, BJF, DF, RS: Interpretation of data/
writing the article. AAF, RN, AAS, and BJF conceived, designed, or planned
the study, interpreted the results, and wrote sections of the initial draft. DF,
CAF, and TLL designed, validated and performed the plasma ascorbic acid
HPLC analysis. SK, CD aided in study design and data collection. RS helped
design the study and wrote sections of the initial draft. SG supervised
biomarker analysis and interpretation of results. EM and DFB provided
substantial review and suggestions of the initial draft. All authors read and
approved the final manuscript.
Acknowledgement
The authors wish to acknowledge support for this phase I trial from: 1) The
Aubrey Sage Macfarlane Acute Lung Injury Fund, 2) VCU Clinical and
Translational Science Award UL1TR000058 from the National Center for
Advancing Translational Sciences, 3) VCU Investigational Pharmacy Services,
4) The Jeffress Memorial Trust, and 5) The AD Williams Trust.
Author details
1
Division of Pulmonary Disease and Critical Care Medicine, Department of
Internal Medicine, School of Medicine, Virginia Commonwealth University,
PO Box 980050, Richmond, VA 23298-0050, USA.
2
Department of Critical Care
Nursing, Virginia Commonwealth University Health System, Richmond,
Virginia, USA.
3
Investigational Drug Services, Department of Pharmacy
Services, School of Pharmacy, Virginia Commonwealth University, Richmond,
Virginia, USA.
4
Division of Nephrology, Department of Internal Medicine,
School of Medicine, Virginia Commonwealth University, Richmond, Virginia,
USA.
5
Department of Pharmacotherapy & Outcomes Science, School of
Pharmacy, Virginia Commonwealth University, Richmond, Virginia, USA.
6
Health Diagnostic Laboratory, Richmond, Virginia, USA.
Received: 12 November 2013 Accepted: 2 January 2014
Published: 31 January 2014
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doi:10.1186/1479-5876-12-32
Cite this article as: Fowler et al.:Phase I safety trial of intravenous
ascorbic acid in patients with severe sepsis. Journal of Translational
Medicine 2014 12:32.
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