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CLINICAL OBSERVATIONS, INTERVENTIONS, AND THERAPEUTIC TRIALS
From the Department of Medicine, University of
Minnesota Medical School, Minneapolis.
The vessel wall endothelium undoubtedly plays a role in the
vascular pathobiology of sickle cell disease. This pilot study tested
the feasibility of using an inhibitor of nuclear factor (NF)- The complex pathophysiology of sickle cell disease
is undoubtedly influenced by the many physiologic functions of the
vascular wall endothelium.1 Even the characteristic
development of acute vascular occlusion due to red cell sickling may be
triggered by proximate adhesion of red cells to endothelial
cells.2,3 This abnormal cell-cell interaction uses
various mechanisms, many of which involve adhesion receptors that can
be expressed on vessel wall endothelial cells. Similarly, other
processes that involve the endothelium, such as thrombosis or
white cell adhesion, may play a role in vascular occlusion.
Through these mechanisms, it is likely that function or
dysfunction of the vascular endothelium contributes to the overall
vascular pathobiology of this disease, which includes recurrent
vaso-occlusions, stroke, chronic organ damage, and neovascularizing retinopathy.
Indirect evidence that the vascular endothelium is abnormally activated
in sickle cell disease comes from the study of circulating endothelial
cells (CECs). We earlier observed that the CECs from patients with
sickle cell disease have abnormally increased expression of adhesion
molecules Recognizing that the clinical efficacy of this approach would need to
be tested and established by appropriate long-term clinical studies, we
conducted the present short-term pilot study to test the basic notion
that inhibition of endothelial activation state is feasible in sickle
cell disease. For this experiment we administered sulfasalazine to
sickle mice and humans with sickle cell disease because it is a
powerful inhibitor of activation of nuclear factor (NF)- Human subjects
For this study the subjects took enteric-coated tablets of
sulfasalazine (Azulfidine; Pharmacia & Upjohn AB, Stockholm, Sweden) and/or salsalate. Both drugs were given at the dose of 1 g orally every 8 hours. Patients A and C tolerated the medications without difficulty and reported taking all scheduled doses; Patient B interrupted his second trial exposure for 3 days due to mild gastric distress and then resumed his regimen. Duration of therapy was from 1-4 weeks. We obtained peripheral blood samples (10-15 mL each) at multiple
time points before, during, and after this protocol for testing of
CECs. Each patient was studied on more than one occasion, separated by
periods of documented return to their baseline for the study end-point
(activated CEC phenotype).
CEC phenotype
We confirmed that the CECs were endothelial by using fluorescein
isothiocyanate (FITC)-labeled mAb P1H12, and we examined them for
expression of selected adhesion molecules by double-staining with
murine mAb to human ICAM-1 or VCAM-1 (Southern Biotechnology Associates, Birmingham, AL) or E-selectin (Novocastra Laboratories, Burlingame, CA). We detected tissue factor expression using a polyclonal rabbit antibody (gift of Dr Ron Bach, University of Minnesota, Minneapolis). The unlabeled primary antibodies were detected
using secondary antibodies: lissamine-rhodamine-labeled mAb to murine
immunoglobulin (Ig) and TRITC-labeled mAb to rabbit Ig (Jackson
Immunoresearch Laboratories, West Grove, PA). We used 2 different
negative controls: (1) same-species, same-isotype irrelevant primary
antibodies and (2) omission of the primary antibodies. For positive
controls we used cultured human umbilical vein endothelial cells that
were stimulated for 6 hours with 1 µg/mL bacterial lipopolysaccharide
or 10 ng/mL tumor necrosis factor (TNF)- Animal studies We used 6- to 8-month-old animals drawn from our colony of sickle transgenic mice, which we established from acquired mice (gift of Dr Mary Fabry, Albert Einstein College of Medicine, Bronx, NY). These mice have a C57Bl/J6 genetic background, they are homozygous for a deletion of murine major globin gene, and they carry
linked transgenes for human alpha and S globins, as
thoroughly characterized previously.12 This study was
conducted under supervision of our institution's animal use committee.
The sickle mice were treated with sulfasalazine, given intraperitoneally as 0.5 mL of a 0.1% solution of drug dissolved in
normal mouse saline (1.024% sodium chloride [NaCl]) adjusted to pH
8.0. Control mice with sickle cell disease were given only vehicle in
identical fashion. These injections were given 3 times daily for 10 days. On a per-weight basis, this amount of drug approximates a dose of
4 g/d given to a 70-kg human. Actual drug levels were not measured.
Animals were euthanized by carbon dioxide (CO2) asphyxiation, and blood was collected by cardiac puncture, followed by rapid collection and freezing of tissue samples. For assessment of activation molecule expression, CECs from mice with sickle cell disease were prepared in the very same manner described above because mAb P1H12 also recognizes murine endothelial cells. These CECs were studied in the same manner as human CECs, but now using rat mAb to murine ICAM-1 or VCAM-1 (Southern Biotechnology) or E-selectin (PharMingen, San Diego, CA). These were detected using secondary antibodies, Cy3-labeled antirat Ig (Jackson Immunoresearch). Because sickle mouse blood contained 70-160 CEC/mL, we also were able to evaluate at least 20 CECs for each antigen in the mouse in virtually all samples. For tissue assessment, frozen tissues were cut to a thickness of 5 µm and fixed in 4% paraformaldehyde for 30 minutes. Sections were stained for the same antigens using the same primary antibodies as used for CECs, except that secondary antibodies were tagged with alkaline phosphatase (Jackson Immunoresearch). Tissues were counterstained with hematoxilin (Sigma Chemical Co, St Louis, MO). As control, we used same-species, same-isotype irrelevant primary antibodies and omission of the primary antibodies. Adjacent sections of tissue were stained with test versus control antibodies to ensure accurate reading of any background staining. For each tissue we evaluated 20-50 high-power fields in at least 5 nonadjacent sections, so that each data point for tissue endothelial antigen expression was derived from analysis of more than 200 vessel segments for capillaries or more than 50 vessel segments for large vessels. We used a quantitative method to score the degree of tissue positivity for adhesion molecules. This was based on histochemical staining (as above) and a 0 to 4+ scale of expression. Values were assigned as follows: 0 indicated no detectable expression; 1+, minimal expression, defined as occasional positive endothelial cells, but overall less than 5% of the vessels being positive; 2+, mild expression, defined as less than 33% of vessels being positive; 3+, moderate expression, defined as the range between 2+ and 4+; and 4+, high degree of expression, defined as more than 80% of blood vessels expressing the test molecule. Tissues were evaluated independently and in blinded fashion by 2 microscopists. They concurred in most (more than 85%) cases; when they did not concur, the microscopists reviewed material together (still blinded) to reach consensus. Statistical analysis Statistical comparison of off-drug versus on-drug murine CECs and endothelium was done using the Student t test. Evaluation of the human trial data employed 3 methods. (1) First, simple inspection of the data was used. In our extensive prior experience with evaluating CECs in patients with sickle cell disease (in the absence of any intervention such as that used here), we examined more than 100 samples each for ICAM, VCAM, E-selectin, and tissue factor. With the exception of one single sample in which VCAM positivity was lower, every one of these samples exhibited 50% or greater CEC positivity. Thus, the expected typical baseline range for sickle samples (50% to 100% positive) is shown by the broken-line box in each panel of Figure 2. (2) For each subject we compared the on-drug values to the 95% CL for the off-drug values. (3) We used the Student t test to generate a nominal P value so we could compare on-drug with off-drug values for each patient. This can be done here for the following reason: Because of the nature of our data set, the value of the covariance term in the calculation of the standard t statistic is unknown. Therefore, the magnitude of t calculated here necessarily is lower than it would be if covariance were known. Therefore, for data comparisons having the nominal P values reported here that are in the significant range (P < .05), the actual P value would be smaller (ie, more significant) than the value shown here.
Sickle mice We examined both capillaries and large vessels in 4 tissues (heart, kidney, liver, and spleen) for expression of 3 molecules that appear on activated endothelium. Of these, VCAM-1 and E-selectin are expressed only upon endothelial activation, while ICAM-1 is constitutively expressed at low levels but increases upon activation.13 In humans with sickle cell disease, all 3 are relevant adhesion molecules for white cells, and VCAM additionally is an adhesion molecule for sickle red blood cells.2,3Using these sickle transgenic mice, we assessed the activation state of
CECs obtained from live animals and then the tissues obtained
immediately thereafter. CECs in the sickle mice were in an activated
state, with a high percentage exhibiting expression of VCAM-1, ICAM-1,
and E-selectin (Table 2, left column),
just as we found previously for humans with sickle cell
anemia.4 Correspondingly, these molecules were expressed
in murine tissue vessels, but the expression pattern was complex.
Details are provided in Figure 1, but
results are briefly summarized here. E-selectin was expressed
moderately in the capillaries of most tissues, but was expressed only
weakly in large vessels. ICAM-1 was expressed moderately strongly in
all large and small vessels of all tissues examined. VCAM-1, on the
other hand, was expressed strongly in large vessels of all tissues, but
not in the capillaries (except for the spleen, which was uniformly
strongly positive). Thus, tissue vessel endothelial activation was
geographically variable, but nevertheless present, in sickle mice at
baseline. Whether or not this activation state in sickle mice is
different from healthy mice cannot be discerned from this study because
our goal was limited to examination of treated and untreated
sickle mice. Our examination of these murine tissues revealed no overt
endothelial damage or denudation.
Compared to animals that received vehicle only, the animals given sulfasalazine for 10 days showed significant decreases in percentage of CECs that were positive for these activation markers (Table 2, right column). Correspondingly, tissue expression of these activation markers on vascular endothelial cells also decreased, variably but significantly for some tissues (Figure 1). In these animal studies we noted that variability in results from animal-to-animal was rather limited (and is evident in error bars in Figure 1) and less than the evident striking organ-to-organ variability in activation antigen expression or even the response to sulfasalazine. Humans with sickle cell disease Our pilot study of endothelial-modulating intervention in humans with sickle cell disease necessarily was limited to analysis of CEC phenotype, and it was deliberately limited to 3 patients for the reasons outlined in "Materials and methods." The patients were given sulfasalazine, and we tested their CEC phenotype (VCAM-1, ICAM-1, E-selectin, and tissue factor) before, during, and after drug administration. Using these 3 subjects we conducted a total of 7 separate trial exposures to sulfasalazine. Results are shown in Figure 2, in which the days on sulfasalazine are indicated at the bottom of each graph by a solid bar, with start and stop days noted on the horizontal axis. Results were dramatic for the adhesion molecules.
Analysis by inspection of Figure 2. During periods of sulfasalazine administration, the degree of CEC activation was lower than during the preceding or following off-drug periods. Virtually all of the on-drug measurements fell below the typical sickle range (Figure 2). The latter is indicated by the dashed box in Figure 2, which identifies the range within which sickle measurements virtually always fall, as indicated in our prior experience. For each of the trial exposures, expression of these 3 CEC activation markers returned to their baseline state promptly after cessation of drug (Figure 2). The transience of this drug effect is perhaps most clearly indicated in the second sulfasalazine trial for patient B, which was interrupted for 3 days (the break in the bar on days 101-103), during which time, ICAM and VCAM positivity immediately returned to baseline range. Analysis of Figure 2 by CL.
In addition to the above analysis by inspection, for each patient we
compared the on-drug values to the 95% CL calculated for that
patient's own off-drug values. As shown in Table
3, there was very little overlap between
values for patients while on drug and their own baseline data for the 3 adhesion molecules.
Statistical analysis of Figure 2.
For each patient we calculated the apparent P value for the
difference between off-drug and on-drug values. This reveals a significant treatment effect for sulfasalazine for the 3 adhesion molecules (Table 4). Because we entered
this project without knowing how long any beneficial effect of
sulfasalazine might last after a drug was stopped, we used 2 conventions to define whether data samplings were on-drug or off-drug
values. In the above analyses, data obtained after the subject had
stopped the study drug were considered to be off-drug values, even in
the cases where there was some lag before return of values to baseline (eg, for the third sulfasalazine trial for patient A). However, the
values obtained on patient B during a brief interruption in administration of study drug (in the second trial exposure) are still
included in our analysis as being on-drug values. It should be noted
that both of these conventions would tend to diminish, rather than
strengthen, the significance of these results.
Clinical considerations have led us to propose that sickle cell disease is characterized by an abnormal state of endothelial cell activation1,2; that is, a state of inflammation. This perspective represents a paradigm shift in how the vascular pathobiology of sickle cell disease might be understood. Supporting this concept, we previously described an abnormal activation phenotype for the CECs found in sickle blood.4,5 Insofar as CEC phenotype is an indicator of the phenotype of vessel wall endothelium, this would imply that an abnormally pro-adhesive and procoagulant vessel wall contributes to clinical sickle disease. This perspective on sickle disease, in turn, predicts that clinical benefit would derive from therapeutics designed to impair unwanted vascular wall participation in disease pathophysiology. Therefore, the primary goal of this very focused pilot study was to examine the feasibility of pharmacologic modification of endothelial activation as a potential therapeutic approach to sickle cell disease. Our results imply that this is possible because we found that sulfasalazine causes a prompt and significant decrease in CEC positivity for VCAM, ICAM, and E-selectin. Therefore, to the extent that activated endothelium participates in the vascular pathobiology of sickle cell disease, we would hope that this interventional strategy would have the clinical benefit of preventing either acute or chronic aspects of sickle disease. It must be emphasized, however, that further data are needed to support this notion. In particular, the extent to which CEC phenotype actually reflects that of vessel wall endothelium needs to be further bolstered (see below), and the extent to what degree of down-regulation of endothelial activation molecules would actually impact on disease pathophysiology needs to be documented. Thus, although this pilot study yielded encouraging results, it has not
attempted to optimize the regimen or even drug selection for
down-regulating endothelial cell activation. In this study we chose
sulfasalazine because it is a powerful inhibitor of NF- A number of agents, most notably glucocorticoids17 and
other anti-inflammatory agents,18 have demonstrated
benefit in vitro for inhibiting NF- In patients receiving sulfasalazine, we have preliminarily observed an
increase in CECs that do not have activated NF- A secondary goal of this study was to obtain simultaneous measurements of activation markers on circulating and tissue endothelial cells. We found that both CEC and vessel wall endothelium were activated in the mouse with sickle cell disease, and the degree of activation of both declined in parallel upon exposure to sulfasalazine. Thus, these data indirectly support the notion that human CEC phenotype reflects that of the vessel wall, at least in a very general sense. In practicality, however, usefulness of CEC analysis clearly is limited because of the highly variable state of endothelial activation we observed from tissue-to-tissue, from vessel-to-vessel, and from antigen-to-antigen. If this variability extends to the human vascular tree, assessment of CEC phenotype cannot provide information of this complexity unless validated tissue-specific endothelial markers become available. Insofar as endothelial activation state impacts on disease genesis, it will be important to develop such methods so that the role of endothelial activation heterogeneity in disease pathophysiology can be understood. Thus, from the standpoint of eventual endothelial therapeutics, there is a great need for studies that bridge the very wide gaps between in vitro observation of transcriptional regulation, measurement of blood CEC phenotype, and potential clinical effects. However, the theoretical value of endothelial-directed therapeutics certainly argues that this strategy deserves further exploration in sickle cell disease. Likewise, there are other vascular diseases that involve endothelial activation and an inflammatory vascular wall phenotype13 such as atherosclerosis,27 so these results have implications beyond sickle cell disease.
Submitted November 24, 1999; accepted November 24, 2000.
Supported by grant PO1 HL55552 from the National Institutes of Health, Bethesda, MD.
The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked "advertisement" in accordance with 18 U.S.C. section 1734.
Reprints: Robert P. Hebbel, Box 480 UMHC, 420 Delaware St SE, Minneapolis, MN 55455; e-mail: hebbe001{at}tc.umn.edu.
1. Hebbel RP, Vercellotti GM. The endothelial biology of sickle cell disease. J Lab Clin Med. 1997;129:288-293[CrossRef][Medline] [Order article via Infotrieve]. 2. Embury SH, Hebbel RP, Steinberg MH, Mohandas N. Pathogenesis of vasoocclusion. In: Embury SH,Hebbel RP,Mohandas N,Steinberg MH, eds. Sickle Disease: Basic Principles and Clinical Practice. New York: Raven Press, Ltd; 1994:311-326. 3. Hebbel RP. Adhesive interactions of sickle erythrocytes with endothelium. J Clin Invest. 1997;99:2561-2564[Medline] [Order article via Infotrieve].
4.
Solovey A, Lin Y, Browne P, Choong S, Wayner E, Hebbel RP.
Circulating activated endothelial cells in sickle cell anemia.
N Engl J Med.
1997;337:1584-1590 5. Solovey A, Gui L, Key NS, Hebbel RP. Tissue factor expression by endothelial cells in sickle cell anemia. J Clin Invest. 1998;101:1899-1904[Medline] [Order article via Infotrieve]. 6. Pober JS, Cotran RS. The role of endothelial cells in inflammation. Transplantation. 1990;50:537-544[Medline] [Order article via Infotrieve].
7.
Osarogiagbon RR, Choong S, Belcher JD, Vercellotti GM, Paller MS, Hebbel RP.
Reperfusion injury pathophysiology in sickle transgenic mice.
Blood.
2000;96:314-320 8. Kaul DK, Hebbel RP. Hypoxia/reoxygenation causes inflammatory response in transgenic sickle mice but not in normal mice. J Clin Invest. 2000;106:411-420[Medline] [Order article via Infotrieve]. 9. Wahl C, Liptay S, Guido A, Schmid RM. Sulfasalazine: a potent and specific inhibitor of nuclear factor kappa B. J Clin Invest. 1998;101:1163-1174[Medline] [Order article via Infotrieve]. 10. Ghosh S, May MJ, Kopp EB. NF-kB and rel proteins: evolutionarily conserved mediators of immune responses. Annu Rev Immunol. 1998;16:225-260[CrossRef][Medline] [Order article via Infotrieve].
11.
Barnes PJ, Karin M.
Nuclear factor-
12.
Fabry ME, Costantini F, Pachnis A, et al.
High expression of human betaS- and alpha-globins in transgenic mice: erythrocyte abnormalities, organ damage, and the effect of hypoxia.
Proc Natl Acad Sci U S A.
1992;89:12155-12159
13.
Cines DB, Pollak ES, Buck CA, et al.
Endothelial cells in physiology and in the pathophysiology of vascular disorders.
Blood.
1998;91:3527-3561 14. Mackman N. Regulation of the tissue factor gene. FASEB J. 1995;9:883-889[Abstract].
15.
Moll T, Czyz M, Holzmüller H, et al.
Regulation of the tissue factor promoter in endothelial cells.
J Biol Chem.
1995;270:3849-3857
16.
Franz B, O'Neill EA.
The effect of sodium salicylate and aspirin on NF-
17.
Auphan N, DiDonato JA, Rosette C, et al.
Immunosuppression by glucocorticoids: inhibition of NF-kB activity through induction of IkB synthesis.
Science.
1995;270:286-290
18.
Kopp E, Ghosh S.
Inhibition of NK-kB by sodium salicylate and aspirin.
Science.
1994;265:956-958 19. Greenberg SS, Xie J, Zhao X, Jie O, Giles TD. An in vivo cytokine and endotoxin-independent pathway for induction of nitric oxide synthase II mRNA, enzyme, and nitrate/nitrite in alveolar macrophages. Biochem Biophys Res Commun. 1996;227:160-167[CrossRef][Medline] [Order article via Infotrieve]. 20. Brack A, Rittner HL, Younge BR, et al. Glucocorticoid-mediated repression of cytokine gene transcription in human arteritis-SCID chimeras. J Clin Invest. 1997;99:2842-2850[Medline] [Order article via Infotrieve]. 21. Taglialatela G, Kaufmann JA, Trevino A, Perez-Polo JR. Central nervous system DNA fragmentation induced by the inhibition of nuclear factor kappa B. Neuroreport. 1998;9:489-493[Medline] [Order article via Infotrieve]. 22. Morishita R, Sugimoto T, Aoki M, et al. In vivo transfection of cis element "decoy" against nuclear factor-kB binding site prevents myocardial infarction. Nat Med. 1997;3:894-899[CrossRef][Medline] [Order article via Infotrieve].
23.
Griffin TC, McIntire D, Buchanan GR.
High-dose intravenous methylprednisolone therapy for pain in children and adolescents with sickle cell disease.
New Engl J Med.
1994;330:733-737
24.
Bernini JC, Rogers ZR, Sandler ES, Reisch JR, Quinn CT, Buchanan GR.
Beneficial effect of intravenous dexamethasone in children with mild to moderately severe acute chest syndrome.
Blood.
1998;92:3082-3089
25.
Solovey AA, Solovey AN, Harkness J, Hebbel RP.
Therapeutic modulation of vascular endothelial cell activation state as therapy for sickle cell disease: NF-
26.
Belcher JD, Marker PH, Weber JP, Hebbel RP, Vercellotti GM.
Activated monocytes in sickle cell disease: potential role in the activation of vascular endothelium and vaso-occlusion.
Blood.
2000;96:2451-2459
27.
Epstein FH.
Atherosclerosis: an inflammatory disease.
N Engl J Med.
1999;340:115-126
© 2001 by The American Society of Hematology.
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  S. D. Nandedkar, T. R. Feroah, W. Hutchins, D. Weihrauch, K. S. Konduri, J. Wang, R. C. Strunk, M. R. DeBaun, C. A. Hillery, and K. A. Pritchard Histopathology of experimentally induced asthma in a murine model of sickle cell disease Blood, September 15, 2008; 112(6): 2529 - 2538. [Abstract] [Full Text] [PDF]
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 |
|
 L. De Franceschi, O. S. Platt, G. Malpeli, A. Janin, A. Scarpa, C. Leboeuf, Y. Beuzard, E. Payen, and C. Brugnara Protective effects of phosphodiesterase-4 (PDE-4) inhibition in the early phase of pulmonary arterial hypertension in transgenic sickle cell mice FASEB J, June 1, 2008; 22(6): 1849 - 1860. [Abstract] [Full Text] [PDF]
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 |
|
 H. Masuda, C. Kalka, T. Takahashi, M. Yoshida, M. Wada, M. Kobori, R. Itoh, H. Iwaguro, M. Eguchi, Y. Iwami, et al. Estrogen-Mediated Endothelial Progenitor Cell Biology and Kinetics For Physiological Postnatal Vasculogenesis Circ. Res., September 14, 2007; 101(6): 598 - 606. [Abstract] [Full Text] [PDF]
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 M. J. Telen Role of Adhesion Molecules and Vascular Endothelium in the Pathogenesis of Sickle Cell Disease Hematology, January 1, 2007; 2007(1): 84 - 90. [Abstract] [Full Text] [PDF]
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 |
|
 R. Buckstein, R. S. Kerbel, Y. Shaked, R. Nayar, C. Foden, R. Turner, C. R. Lee, D. Taylor, L. Zhang, S. Man, et al. High-Dose Celecoxib and Metronomic "Low-dose" Cyclophosphamide Is an Effective and Safe Therapy in Patients with Relapsed and Refractory Aggressive Histology Non-Hodgkin's Lymphoma Clin. Cancer Res., September 1, 2006; 12(17): 5190 - 5198. [Abstract] [Full Text] [PDF]
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G. J. Kato, V. McGowan, R. F. Machado, J. A. Little, J. Taylor VI, C. R. Morris, J. S. Nichols, X. Wang, M. Poljakovic, S. M. Morris Jr, et al. Lactate dehydrogenase as a biomarker of hemolysis-associated nitric oxide resistance, priapism, leg ulceration, pulmonary hypertension, and death in patients with sickle cell disease Blood, March 15, 2006; 107(6): 2279 - 2285. [Abstract] [Full Text] [PDF]
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|
K. W. Lee, G. Y. H. Lip, M. Tayebjee, W. Foster, and A. D. Blann Circulating endothelial cells, von Willebrand factor, interleukin-6, and prognosis in patients with acute coronary syndromes Blood, January 15, 2005; 105(2): 526 - 532. [Abstract] [Full Text] [PDF]
|
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A. Solovey, R. Kollander, A. Shet, L. C. Milbauer, S. Choong, A. Panoskaltsis-Mortari, B. R. Blazar, R. J. Kelm Jr, and R. P. Hebbel Endothelial cell expression of tissue factor in sickle mice is augmented by hypoxia/reoxygenation and inhibited by lovastatin Blood, August 1, 2004; 104(3): 840 - 846. [Abstract] [Full Text] [PDF]
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|
 D. K. Kaul, X.-d. Liu, S. Choong, J. D. Belcher, G. M. Vercellotti, and R. P. Hebbel Anti-inflammatory therapy ameliorates leukocyte adhesion and microvascular flow abnormalities in transgenic sickle mice Am J Physiol Heart Circ Physiol, July 1, 2004; 287(1): H293 - H301. [Abstract] [Full Text] [PDF]
|
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|
|
|
G. R. Buchanan, M. R. DeBaun, C. T. Quinn, and M. H. Steinberg Sickle Cell Disease Hematology, January 1, 2004; 2004(1): 35 - 47. [Abstract] [Full Text] [PDF]
|
|
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|
 |
|
 F. A. D. T. G. Wagener, H.-D. Volk, D. Willis, N. G. Abraham, M. P. Soares, G. J. Adema, and C. G. Figdor Different Faces of the Heme-Heme Oxygenase System in Inflammation Pharmacol. Rev., September 1, 2003; 55(3): 551 - 571. [Abstract] [Full Text] [PDF]
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N. Perelman, S. K. Selvaraj, S. Batra, L. R. Luck, A. Erdreich-Epstein, T. D. Coates, V. K. Kalra, and P. Malik Placenta growth factor activates monocytes and correlates with sickle cell disease severity Blood, August 15, 2003; 102(4): 1506 - 1514. [Abstract] [Full Text] [PDF]
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 M. S. Segal, A. Bihorac, and M. Koc Circulating endothelial cells: tea leaves for renal disease Am J Physiol Renal Physiol, July 1, 2002; 283(1): F11 - F19. [Abstract] [Full Text] [PDF]
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 M. Aslan, T. M. Ryan, B. Adler, T. M. Townes, D. A. Parks, J. A. Thompson, A. Tousson, M. T. Gladwin, R. P. Patel, M. M. Tarpey, et al. Oxygen radical inhibition of nitric oxide-dependent vascular function in sickle cell disease PNAS, December 18, 2001; 98(26): 15215 - 15220. [Abstract] [Full Text] [PDF]
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B. N. Y. Setty, A. K. Rao, and M. J. Stuart Thrombophilia in sickle cell disease: the red cell connection Blood, December 1, 2001; 98(12): 3228 - 3233. [Abstract] [Full Text] [PDF]
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 T. Stevens, R. Rosenberg, W. Aird, T. Quertermous, F. L. Johnson, J. G. N. Garcia, R. P. Hebbel, R. M. Tuder, and S. Garfinkel NHLBI workshop report: endothelial cell phenotypes in heart, lung, and blood diseases Am J Physiol Cell Physiol, November 1, 2001; 281(5): C1422 - C1433. [Abstract] [Full Text] [PDF]
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Top
Abstract
Introduction
B, a
transcription factor, to modify the endothelial activation state
of patients with this vascular disease. For a total of 7 separate
drug exposure tests, 3 subjects with sickle cell disease took
sulfasalazine (given orally at 1 g every 8 hours), and the activation state of their circulating endothelial cells (CECs) was
assessed using immunofluorescence microscopy. Companion studies were
also performed using sulfasalazine in sickle transgenic mice to
verify its effect simultaneously on both CECs and vessel wall endothelium. Both CECs and tissue vessel wall endothelium in sickle mice have an activated phenotype. In these mice sulfasalazine significantly reduced CEC expression of vascular cell adhesion molecule
(VCAM), intracellular adhesion molecule (ICAM), and E-selectin, and it
correspondingly reduced expression of these molecules in some tissue
vessels. In humans with sickle cell disease, sulfasalazine significantly reduced CEC expression of VCAM, ICAM, and E-selectin, but
it did not reduce expression of tissue factor. Addition of a second
transcription factor inhibitor, salsalate, did not change this result.
This pilot study suggests that endothelial cell activation state
can be modified and down-regulated in vivo by sulfasalazine.
(Blood. 2001;97:1937-1941)
vascular cell adhesion molecule (VCAM), intercellular
adhesion molecule (ICAM), and E-selectin
. For each blood sample we
recorded the percentage of CECs that were positive for expression of
the molecule of interest. CECs were scored as negative if they had no
more staining than the negative control samples. Because blood from
patients with sickle cell disease averages 13 CEC/mL in the steady
state,
