Antifosfolipidi e vitamine antiossidanti
Antifosfolipidi e vitamine antiossidanti
"Antiphospholipid Antibodies Are Directed against Epitopes of Oxidized Phospholipids"
Recognition of Cardiolipin by Monoclonal Antibodies to Epitopes of Oxidized Low Density Lipoprotein
J. Clin. Invest. Volume 98, Number 3, August 1996, 815-825
Sohvi Hörkkö*, Elizabeth Miller*, Eric Dudl*, Peter Reaven*, Linda K. Curtiss, Nathan J. Zvaifler*,
Robert Terkeltaub*, Silvia S. Pierangeli§, D. Ware Branch, Wulf Palinski*, and Joseph L. Witztum*
* Department of Medicine, University of California, San Diego, California 92093; Departments
of Immunology and Vascular Biology, The Scripps Research Institute, La Jolla, California 92037;
§ Antiphospholipid Standardization Laboratory, Department of Medicine, University of Louisville,
Louisville, Kentucky 40208; and Departments of Obstetrics and Gynecology, University of Utah,
Health Sciences Center, Salt Lake City, Utah 84112
Abstract
The optimal clinical management of patients with antiphospholipid antibody syndrome (APS) is
uncertain because of a lack of an underlying hypothesis to explain why antiphospholipid
autoantibodies (aPL) form to such ubiquitous compounds as phospholipids (PL). In this paper, we
demonstrate that many, if not most, aPL are actually directed at neoepitopes of oxidized PL, or
neoepitopes generated by adduct formation between breakdown products of oxidized PL and
associated proteins. Each cardiolipin (CL) molecule contains four unsaturated fatty acids and is
highly susceptible to oxidation, particularly upon exposure to air. Yet, standard anticardiolipin
antibodies (aCL) immunoassays routinely bind CL to microtiter wells by evaporation of the ethanol
solvent overnight at 4°C. Using a variety of techniques, we demonstrated that rapid oxidation
occurs when CL is plated and exposed to air. Sera from apo E-deficient mice, which have high
autoantibody titers to oxidized low density lipoprotein, showed a striking time-dependent increase
in binding to CL that was exposed to air for increasing periods of time. Monoclonal antibodies to
oxidized LDL, cloned from the apo E-deficient mice, also bound to oxidized CL. Both sera and
affinity-purified aCL-IgG from APS patients bound to CL progressively as it was oxidized.
However, the monoclonal antibodies from apo E-deficient mice, or sera or aCL-IgG from APS
patients did not bind to a reduced CL analog that was unable to undergo peroxidation. These data
demonstrate that many aPL are directed at neoepitopes of oxidized phospholipids, and suggest that
oxidative events may be important in the pathophysiology of APS. In turn, this suggests new
therapeutic strategies, possibly including intensive antioxidant therapy.
(J. Clin. Invest.1996. 98:815-825.)
Enhanced Lipid Peroxidation in Patients Positive for Antiphospholipid Antibodies
Blood, Vol. 90 No. 10 (November 15), 1997: pp. 3931-3935
By Luigi Iuliano, Domenico Praticò, Domenico Ferro, Valerio Pittoni, Guido
Valesini, John Lawson, Garret A. FitzGerald, and Francesco Violi
From The Institute of Clinical Medicine I, University "La Sapienza," Rome, Italy; and The Center
for Experimental Therapeutics, The University of Pennsylvania, Philadelphia, PA.
Abstract
The mechanism leading to the formation of antiphospholipid antibodies
(aPL) is still unknown. Because an in vitro study suggested that aPL may
derive from pro-oxidant conditions, we sought a relationship between aPL
and isoprostanes, indices of lipid peroxidation in vivo. Thirty patients with
systemic lupus erythematosus have been studied. Seventeen (56.6%) were
positive for aPL because they had lupus anticoagulant and/or high titer of
anticardiolipin antibodies (aCL). Plasma levels of tumor necrosis factor (TNF ) and urinary
excretion of two isoprostanes, 8-epi-PGF2 and IPF2 -I, free radical catalyzed oxidation products
of arachidonic acid, were measured. Patients with systemic lupus erythematosus had higher urinary
excretion of 8-epi-PGF2 and IPF2 -I than controls; urinary excretion of the two isoprostanes was
highly correlated (Rho = 0.74, P < .0001). Urinary 8-epi-PGF2 was highly correlated with both
aCL titer (Rho = 0.70, P < .0001) and TNF (Rho = 0.84, P < .0001), a measure of disease
severity. Excretion of this isoprostane was also higher in those patients who exhibited aPL (P <
.0001). Comparable correlations were observed with the isoprostane IPF2 -I. No difference of
8-epi-PGF2 was observed between patients with and without previous history of thrombosis. This
study, showing the existence of a close association between aPL and increased in vivo lipid
peroxidation, supports the hypothesis that these antibodies may result from pro-oxidative conditions
and suggests that inflammation may play an important role.
Ongoing Prothrombotic State in Patients
With Antiphospholipid Antibodies: A Role
for Increased Lipid Peroxidation
Blood, Vol. 93 No. 10 (May 15), 1999: pp. 3401-3407
Domenico Praticò, Domenico Ferro, Luigi Iuliano, Joshua Rokach, Fabrizio Conti, Guido Valesini,
Garret A. FitzGerald, and Francesco Violi
From the Institute of Clinical Medicine I, University "La Sapienza," Rome, Italy; and the Center for Experimental
Therapeutics, University of Pennsylvania, Philadelphia, PA.
Abstract
We measured the urinary excretion of Isoprostane F2-III and Isoprostane-F2-VI, two markers of in vivo lipid
peroxidation, and the circulating levels of the prothrombin fragment F1+2, a marker of thrombin generation, in
18 antiphospholipid antibodies-positive patients, in 18 antiphospholipid antibodies-negative patients with systemic lupus erythematosus, and in 20 healthy subjects. Furthermore, 12 patients positive for antiphospholipid antibodies were treated with (n = 7) or without (n = 5) antioxidant vitamins (vitamin E at 900 IU/d and vitamin C at 2,000 mg/d) for 4 weeks. Compared with antiphospholipid antibodies-negative patients, antiphospholipid
antibodies-positive patients had higher urinary values of Isoprostane-F2-III (P = .0001), Isoprostane-F2-VI (P
= .006), and plasma levels of the prothrombin fragment F1+2 (P = .0001). In antiphospholipid-positive patients,
F1+2 significantly correlated with Isoprostane-F2-III (Rho = .56, P = .017) and Isoprostane-F2-VI (Rho
= .61, P = .008). After 4 weeks of supplementation with antioxidant vitamins, we found a significant decrease in
F1+2 levels (P < .005) concomitantly with a significant reduction of both Isoprostane-F2-III (P = .007) and
Isoprostane-F2-VI (P < .005). No change of these variables was observed in patients not receiving antioxidant
treatment. This study suggests that lipid peroxidation might contribute to the activation of clotting system in
patients positive for antiphospholipid antibodies.
Pagina principale
