Clinical and Inflammatory Effects of Dietary L-Arginine
in Patients With Intractable Angina Pectoris
Arnon Blum, MD, Reuven Porat, MD, Uri Rosenschein, MD, Gad Keren, MD,
Arie Roth, MD, Shlomo Laniado, MD, and Hylton Miller, MB
N
itric oxide (NO) is primarily synthesized by en-
dothelial cells and is a potent vasodilator. L-
arginine, a precursor of the enzyme nitric oxide syn-
thase (NOS)
1
has been extensively studied in animal
models and in human beings. L-arginine enhances NO
bioavailability in the vascular endothelium,
2
attenu-
ates enhanced monocyte-vascular endothelium adhe-
siveness, and restores endothelium-dependent vasodi-
lation.
3
L-arginine can be given intra-arterially,
4
intra-
venously,
5
and orally.
6
The advantage of the oral route
is the longer half-life and longer term effect, which are
both short (1 minute) in the intra-arterial and the
intravenous routes. This study assesses the effects of
oral L-arginine on the clinical and inflammatory state
of patients with coronary artery disease and intractable
angina pectoris.
•••
The inclusion criteria were coronary artery disease
documented by coronary angiography, angina pectoris
functional class IV, previous revascularization (coro-
nary angioplasty or coronary artery bypass surgery),
and a thallium perfusion scan that demonstrated a
reversible perfusion defect in 1 segment. The exclu-
sion criteria included significant heart failure (New
York Heart Association more than or equal to class
III), chronic disease, and malignancy. This study was
a prospective, case-controlled, pilot study. Ten men
were enrolled, all had undergone coronary angiogra-
phy and angioplasty, and 9 had undergone coronary
artery bypass surgery before enrollment. All suffered
angina pectoris class IV and had frequent attacks of
angina at rest and at night despite large doses of
blockers, calcium channel blockers, nitrates, and as-
pirin; no further intervention could be offered to these
patients. The average age was 72 10 years (range 48
to 80); all were men with hypercholesterolemia (well
treated), 6 were hypertensive, and 4 had diabetes
mellitus (noninsulin dependent). Mean left ventricular
ejection fraction was 56 13%. Each patient had a
clinical examination before starting the study, and
monthly afterwards for 3 months. Patients were re-
quested to fill out The Seattle Angina Questionnaire
7,8
before treatment and after 1 and 3 months of treat-
ment.
Blood samples were taken at enrollment and at
each of the 3 monthly visits. The serum was separated
by centrifugation and stored at -70° C until analyzed
in 1 batch. Serum concentration of soluble intercellu-
lar adhesion molecule-1 (sICAM-1), vascular cell ad-
hesion molecule-1 (sVCAM-1), E-selectin, P-selectin,
and L-selectin were measured by monoclonal anti-
body based enzyme-linked immunosorbent assay kits
(British Biotechnology Products Ltd., Abdington, Ox-
fordshire, United Kingdom and Takara Biomedicals,
Kurume, Japan). Briefly, known concentrations (for a
standard curve) of adhesion molecules and serum
samples (100 l) were added to 96-well plates pre-
coated with the first monoclonal antibody and incu-
bated for 1 to 2 hours at 37°C. After washing, a second
antibody labeled with horseradish peroxidase was
added for additional inclusion (1 hour at 37°C) and the
plates were vigorously washed again. Substrate solu-
tions were then added for a short incubation period (30
minutes) followed by the addition of 1 N H
2
SO
4
, and
the reaction stopped. Absorbance was read at 492 nm.
Serum concentrations of cellular adhesion molecules
were calculated based on the standard curve. Circu-
lating tumor necrosis factor-, interleukin 1-, and
interleukin-6 were measured by specific non– cross-
reactive radioimmunoassay as described.
9-11
Cytokine
concentrations were read from a log plot of percent
specific binding versus the log concentration of seri-
ally diluted standard cytokines from the linear portion
of the curve (between 35% to 75% specific binding).
The lower limit of detection of the assays were 40 pg
for tumor necrosis-, and 78 pg for interleukin 1-
and interleukin-6.
Data were expressed as mean SD. For data
comparisons the nonparametric test for 2 matched
samples and the paired Student’s t test were used.
All patients took L-arginine 9 g daily for 3 months.
No one reported side effects from the L-arginine (con-
stipation, diarrhea, hypotension, abdominal cramps).
Seven patients improved clinically (from angina pec-
toris functional class IV to functional class II); their
improvement was persistent and continued as long as
L-arginine was taken. Discontinuing L-arginine sup-
plementation (after 3 months) caused a “rebound phe-
nomena,” and they deteriorated to functional class IV.
One patient improved to functional class III, and 2
patients remained in functional class IV.
After 1 month of L-arginine, cell adhesion mole-
cule and cytokine levels remained stable throughout 3
months of the study. Individual data are presented in
Table I. In 7 patients who had a significant clinical
improvement, P-selectin level decreased from 338
40 pg/ml to 304 31 pg/ml (p = 0.01), ICAM level
decreased from 315 57 pg/ml to 274 36 pg/ml
(p = 0.08), and E-selectin changed from 47 10 to
44 11 (p = 0.09). VCAM and L-selectin levels
From the Cardiology Branch, National Heart, Lung, and Blood Insti-
tute, National Institutes of Health, Bethesda, Maryland; and Cardiol-
ogy Department and Internal Medicine B, Tel-Aviv Sourasky Medical
Center and Tel-Aviv University, Tel-Aviv, Israel. Dr. Miller’s address is:
Catheterization Laboratory, Tel-Aviv Medical Center, 6 Weizman St.,
Tel-Aviv, 64239, Israel. E-mail: himiller@tasmc.health.gov.il. Manu-
script received November 19, 1998; revised manuscript received
and accepted January 14, 1999.
1488 ©1999 by Excerpta Medica, Inc. 0002-9149/99/$–see front matter
All rights reserved. PII S0002-9149(99)00129-0