Skip Navigation LinksHome > November 2011 - Volume 118 - Issue 5 > Aspirin and Heparin Effect on Basal and Antiphospholipid Ant...
Obstetrics & Gynecology:
doi: 10.1097/AOG.0b013e31823234ad
Original Research

Aspirin and Heparin Effect on Basal and Antiphospholipid Antibody Modulation of Trophoblast Function

Han, Christina S. MD; Mulla, Melissa J. MS; Brosens, Jan J. MD, PhD; Chamley, Larry W. PhD; Paidas, Michael J. MD; Lockwood, Charles J. MD; Abrahams, Vikki M. PhD

Free Access
Cochrane Reviews
Clinical ObGyn
Article Outline
Collapse Box

Author Information

From the Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology & Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut; Warwick Medical School, Clinical Sciences Research Institute, Coventry, United Kingdom; and the Department of Obstetrics and Gynecology, University of Auckland, Auckland, New Zealand.

Supported by grants from Yale Women's Reproductive Health Research (WRHR) Career Development Center (K12 HD 047018-07, under Charles J. Lockwood, MD) and the American Heart Association (under Vikki M. Abrahams, PhD).

Presented as an abstract and poster at the 58th Annual Meeting of the Society of Gynecologic Investigation on March 16–19, 2011, in Miami Beach, Florida.

Corresponding author: Christina S. Han, MD, Department of Obstetrics, Gynecology & Reproductive Sciences, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8063; e-mail: christina.han@yale.edu.

Financial Disclosure The author did not report any potential conflicts of interest.

Collapse Box

Abstract

OBJECTIVE: Low molecular weight (LMW) heparin, with or without aspirin (acetylsalicylic acid [ASA]), is used to prevent complications in antiphospholipid syndrome in pregnancy. Our objective was to elucidate the actions of low-dose LMW heparin and ASA on basal and antiphospholipid antibody-induced modulation of trophoblast function.

METHODS: The human first-trimester trophoblast cell line (HTR-8) was treated with or without antiphospholipid antibody in the presence of no medication, low-dose LMW heparin, low-dose ASA, or combination therapy. Interleukin (IL)-6, IL-8, IL-1β, growth-regulated oncogene-α, vascular endothelial growth factor (VEGF), placental growth factor, soluble FMS-like tyrosine kinase-1, and soluble endoglin were measured in the supernatant. Cell migration was performed using a two-chamber assay.

RESULTS: Low molecular weight heparin improved basal trophoblast migration and induced potent increases in growth-regulated oncogene-α and soluble FMS-like tyrosine kinase-1. Aspirin did not affect basal function. Combined therapy promoted migration but did not reverse the LMW heparin-induced soluble FMS-like tyrosine kinase-1 effect. Antiphospholipid antibody increased IL-8, IL-1β, growth-regulated oncogene-alpha, VEGF, placental growth factor, and soluble endoglin secretion, while decreasing cell migration and IL-6 and soluble FMS-like tyrosine kinase-1 secretion. The antiphospholipid antibody-induced cytokine changes were best reversed with LMW heparin, with partial reversal of IL-8 and IL-1β upregulation. The antiphospholipid antibody-induced angiogenic changes were worsened by LMW heparin, with increased soluble FMS-like tyrosine kinase-1 secretion. The therapies did not reverse antiphospholipid antibody-induced decrease in migration.

CONCLUSION: In the absence of antiphospholipid antibodies, LMW heparin induces potentially detrimental proinflammatory and antiangiogenic profile in the trophoblast. In the presence of antiphospholipid antibodies, single-agent LMW heparin may be the optimal therapy to counter trophoblast inflammation, but also induces an antiangiogenic response. These findings may explain the inability of current therapies to consistently prevent adverse outcomes.

LEVEL OF EVIDENCE: II

Pregnancies affected by antiphospholipid syndrome are managed with heparin, either alone or in combination with acetylsalicylic acid (ASA), with prevention of maternal and fetal adverse outcomes as the goal.1,2 Although low molecular weight (LMW) heparin is standard with a history of thromboembolism, studies regarding its effectiveness for the prevention of antiphospholipid syndrome-associated adverse pregnancy outcomes have been fraught with contradiction.38 Furthermore, late pregnancy complications remain prevalent despite heparin therapy.3,4

Similarly, some studies of ASA in antiphospholipid syndrome found an increased live birth rate,7 whereas others did not.9,10 Nonetheless, ASA has gained favor as prophylaxis for recurrent intrauterine growth restriction (IUGR) or pre-eclampsia in nonantiphospholipid syndrome pregnancies. A recent meta-analysis reported that ASA initiated before 16 weeks of gestation decreases risk of recurrent pre-eclampsia (relative risk 0.47, 95% confidence interval [CI] 0.34–0.65), severe pre-eclampsia (relative risk 0.09, 95% CI 0.02–0.37), and IUGR (relative risk 0.44, 95% CI 0.30–0.65), whereas ASA started after 16 weeks of gestation yielded no benefit.11

The effects of these medications on third trimester trophoblasts previously had been reported;12 however, dysregulation of first-trimester trophoblast function is a stronger mediator in the development of adverse pregnancy outcomes.13,14 Previous studies by our group have demonstrated that antiphospholipid antibodies adversely affect human first-trimester trophoblast function by reducing cell migration and inducing a potentially unfavorable proinflammatory cytokine and altered angiogenic factor milieu.1517 Therefore, given the controversies, we sought to elucidate the action of these compounds on human first-trimester trophoblast function in the absence and presence of antiphospholipid antibodies.

Back to Top | Article Outline

MATERIALS AND METHODS

Sterile LMW heparin, enoxaparin sodium injection, 100 mg/mL, was purchased from Aventis Pharmaceuticals. Acetylsalicylic acid was obtained from Sigma-Aldrich and was reconstituted in diluted ethanol and filter-sterilized before use. No significant differences in measured outcomes were seen with ethanol controls.

A mouse antihuman beta-2-glycoprotein-1 (β2-GPI) monoclonal IgG1, designated ID2, was chosen to mimic antiphospholipid syndrome in pregnancy in vitro, because of its well-characterized properties.12,13,18 Similar to human polyclonal antiphospholipid antibodies, ID2 binds β2-GPI when immobilized on a suitable negatively charged surface,19 binds to human first-trimester trophoblast,15,20 and alters first-trimester trophoblast function.1517

The human first trimester extravillous cytotrophoblast cell line, HTR-8, was used,21 and was a gift from Dr. Charles Graham (Queens University, Kingston, Ontario, Canada). Cells were cultured in RPMI 1640 media (Gibco), supplemented with 10% fetal bovine serum (Hyclone), 10 mm Hepes, 0.1 mm minimal essential medium nonessential amino acids, 1 mm sodium pyruvate, and 100 nm penicillin-streptomycin (Gibco). Cells were maintained at 37°C with 5% CO2. These cells respond to antiphospholipid antibodies similarly to primary first-trimester trophoblast cultures.15,17

HTR-8 cells were treated with or without ID2 (20 micrograms/mL) in the presence and absence of: 1) media-only, no treatment control; 2) low-dose LMW heparin (10 micrograms/mL); 3) low-dose ASA (10 micrograms/mL); or 4) combination low-dose LMW heparin plus ASA (10 micrograms/mL each) in OptiMEM (Invitrogen). As control, cells were also treated with ethanol, which had no effect (data not shown). Cell-free supernatants were collected after 72-hour culture, centrifuged at 1,500g for 10 minutes, and stored at −80°C. The concentrations of ASA and LMW heparin used in this study were based on a previous report and equivalent to low-dose medications used in the clinical setting.12,22

Cytokines and angiogenic factor concentrations in the supernatant were evaluated by enzyme-linked immunosorbent assay (Assay Designs) and multiplex assay (Luminex, Austin, TX). Proinflammatory cytokines assayed were interleukin (IL)-6, IL-8, IL-1β, and growth-regulated oncogene-α (a monocyte chemoattractant). Proangiogenic factors assayed were vascular endothelial growth factor (VEGF) and placental growth factor, and antiangiogenic factors assayed were soluble FMS-like tyrosine kinase-1 and soluble endoglin. We have previously demonstrated that antiphospholipid antibodies modulates first-trimester trophoblast secretion of all of these factors.1517

A two-chamber assay was used for the migration studies to measure the spontaneous migratory property of the trophoblast that occurs during normal implantation, which has been previously described by our group.15 The lower chamber for this assay consisted of 24-well tissue culture plates (BD Falcon), which contained 800 microliters of treatment media. Trophoblast cells (1×105 cells in 200 microliters of respective treatment media) were then seeded into a cell culture well insert with 8-micrometer pore size membrane (BD Biosciences), which served as the upper chamber. Cells were treated with the same combinations of ID2, ASA, and LMW heparin as described. After 48-hour incubation, trophoblast migration across the membranes was determined using the QCM 24-Well Colorimetric Cell Migration Assay (Chemicon International). The resulting colored mixture was read in triplicate at 560 nm using a BioRad plate reader and compared with a 100% cell control to determine relative percent migration.

Experiments were performed three times and assayed in duplicate. Data were then pooled and expressed as mean±standard deviation. Statistical significance (P<.05) was determined using analysis of variance.

Back to Top | Article Outline

RESULTS

Low molecular weight heparin and ASA are both known to have anti-inflammatory properties.2325 The first objective of this study therefore was to determine the effects of these therapies on basal cytokine/chemokine production by first-trimester trophoblast. As shown in Figure 1, LMW heparin significantly increased basal growth-regulated oncogene-α secretion by 269%±18.5% (P=.006), without affecting secretion of IL-6, IL-8, and IL-1β. Acetylsalicylic acid alone did not have any significant effect on the basal levels of secreted IL-8, IL-6, growth-regulated oncogene-α, or IL-1β. Treatment of trophoblast with both LMW heparin and ASA fully reversed the upregulation of growth-regulated oncogene-α induced by single-agent LMW heparin therapy.

Fig. 1
Fig. 1
Image Tools

The next objective of this study was to determine the effect of the therapies on basal trophoblast secretion of proangiogenic (VEGF and placental growth factor) and antiangiogenic factors (soluble FMS-like tyrosine kinase-1 and soluble endoglin). Although a previous report by our group showed that high-dose LMW heparin (100 micrograms/mL) upregulated HTR-8 placental growth factor and soluble FMS-like tyrosine kinase-1 secretion,16 the effects of a low-dose LMW heparin (10 micrograms/mL) on these factors had not yet been evaluated. As shown in Figure 2, treatment with low-dose LMW heparin induced an antiangiogenic state, with a 262.5%±43.6% increase in soluble FMS-like tyrosine kinase-1 (P<.001) and 34.0%±6.3% reduction in VEGF (P<.001). The proangiogenic placental growth factor also increased by 230.2%±85.4% (P<.001). Acetylsalicylic acid had no effects on the production of these angiogenic factors by trophoblasts. Combination treatment resulted in the same effects as single-therapy LMW heparin.

Fig. 2
Fig. 2
Image Tools

The next objective of this study was to determine the effects of the therapies on basal trophoblast migration. We previously reported that high-dose LMW heparin augmented basal trophoblast migration.17 As shown in Figure 3, single-agent low-dose LMW heparin also induced this promigratory phenomenon, with a 133.6%±9.9% increase in migration (P<.001). Because ASA is also used routinely for prophylaxis against recurrent pre-eclampsia and IUGR,11 we speculated that ASA would have an overall promigratory effect on the first-trimester trophoblast. Treatment with low-dose ASA, however, did not induce any changes in the migratory capacity of HTR-8 trophoblasts. Combination therapy, however, modestly augmented the LMW heparin-dependent increase in migratory capacity by an additional 4.6%±2.1% (P<.001).

Fig. 3
Fig. 3
Image Tools

Having determined the effects of the treatment regimens on basal trophoblast function, we next sought to determine the effects of LMW heparin and ASA on antiphospholipid antibodies-mediated alterations in the trophoblast function, beginning with cytokine/chemokine production. Consistent with our previous reports,17 treatment of the HTR-8 cell line with the anti-β2GPI monoclonal antibody, ID2 (20 micrograms/mL), significantly decreased IL-6 secretion by 40.7%±11.7% (P<.001) and increased the secretion of IL-8 by 641.3%±376.3% (P<.001), growth-regulated oncogene-α by 541.1%±52.8% (P<.001), and IL-1β by 508.8%±10.5% (P<.001; Fig. 4).

Fig. 4
Fig. 4
Image Tools

Treatment with LMW heparin did not reverse the antiphospholipid antibodies-induced downregulation of IL-6, but it attenuated the antiphospholipid antibodies-induced elevations of IL-8 and IL-1β secretion (Fig. 4). The augmentation of growth-regulated oncogene-α levels with LMW heparin treatment (Fig. 1C) was maintained in the presence of antiphospholipid antibodies, although the response was more pronounced (Fig. 4C). Single-agent ASA therapy did not affect any of the antiphospholipid antibodies-induced cytokines or chemokine responses (Figs. 4A–D). Combination LMW heparin and ASA treatment did minimally reverse the growth-regulated oncogene-α effect (Fig. 4C), but it did not offer any other additional anti-inflammatory effect.

We next turned our attention to the effects of the therapies on antiphospholipid antibodies-mediated modulation of angiogenic factor production. As previously reported,26 antiphospholipid antibodies significantly increased HTR-8 secretion of VEGF by 145.5%± 18.1% (P<.001), placental growth factor by 224.5%± 45.4% (P<.001), and soluble endoglin by 278.7%± 192.5% (P<.001), while decreasing soluble FMS-like tyrosine kinase-1 by 28.7%±12.4% (P=.012; Fig. 5).

Fig. 5
Fig. 5
Image Tools

None of the treatment regimens altered the antiphospholipid antibodies-induced changes in levels of VEGF or soluble endoglin (Fig. 5A, D). Treatment with single-agent LMW heparin further augmented the antiphospholipid antibodies-induced placental growth factor secretion by 159.7%±19.5% (P<.001), whereas ASA had no significant effect. The addition of ASA to LMW heparin in combination therapy yielded a similar effect on placental growth factor as treatment with LMW heparin alone (Fig. 5B). As with the basal state, LMW heparin caused a significant elevation of soluble FMS-like tyrosine kinase-1 accumulation in supernatant, even though the antiphospholipid antibodies alone reduced soluble FMS-like tyrosine kinase-1 levels, and combination therapy with ASA was unable to reverse this profound response (Fig. 5C).

The final objective was to determine the effects of the therapies on antiphospholipid antibodies-mediated modulation of trophoblast migration. As seen in Figure 6, and in our previous report,17 antiphospholipid antibodies significantly reduced trophoblast migration by 59.2%±2.4% (P<.001). None of the therapies was able to reverse the effect (Fig. 6).

Fig. 6
Fig. 6
Image Tools
Back to Top | Article Outline

DISCUSSION

Despite conflicting data on the efficacy of heparin and ASA therapies in preventing adverse pregnancy outcomes, pregnant women with antiphospholipid syndrome are routinely treated with LMW heparin, either alone or in combination with ASA.916,18,19,21 Whereas several studies have reported on the anti-inflammatory properties of LMW heparin and ASA,3,2729 there is a paucity of literature on the effects of these therapies on first-trimester trophoblast, a major player in the pathogenesis of a spectrum of obstetrical disorders.13 Given the heterogeneity in clinical outcomes with heparin and ASA therapy, it is increasingly apparent that the action of these therapies, as single agents or in combination, need to be better-elucidated to individualize and optimize therapies.

We focused our current study on human first-trimester trophoblast given their unique susceptibility to antiphospholipid antibodies with β2-GPI activity and their role in the development of pregnancy complications.13,14 Trophoblasts synthesize their own β2-GPI,12 and whereas most cells will only bind β2-GPI on their cell surface under pathologic conditions when there is exteriorization of negatively charge phospholipids on the outer surface of the plasma membrane, the rapid proliferation and differentiation of trophoblasts render them able to express endogenous and bind exogenous β2-GPI on the cell surface under normal physiological conditions.13 Thus, anti-β2-GPI antibodies target the trophoblast surface, establishing the pathogenic placental environment in antiphospholipid syndrome.13

The present study demonstrates the multiplicity and complexity of the effects of LMW heparin and ASA on trophoblast function in the presence and absence of antiphospholipid antibodies. Contrary to previous studies demonstrating anti-inflammatory effects of LMW heparin,3,2729 using our trophoblast in vitro model, single-agent LMW heparin was actually shown to have both proinflammatory and anti-inflammatory effects. Our finding that low molecular weight heparin increased basal and antiphospholipid antibody-induced trophoblast secretion of growth-regulated oncogene-α, a potent monocyte chemoattractant, is novel, although the potential clinical significance and mechanism are currently unknown. Whereas basal IL-6, IL-8, and IL-1β were not affected by either LMW heparin or ASA, the antiphospholipid antibodies-mediated elevations in IL-8 and IL-1β were partially reversed by single-agent LMW heparin. Interestingly, although ASA alone had no effect on basal or antiphospholipid antibodies-induced cytokine production, in combination with LMW heparin, growth-regulated oncogene-α levels in the absence of antiphospholipid antibodies were brought back to baseline, suggesting that ASA can counteract the proinflammatory actions of LMW heparin.

These combined cytokine/chemokine findings may explain the inability of LMW heparin and ASA to consistently reverse the inflammation-induced endpoints seen in antiphospholipid syndrome. None of the therapies proved beneficial to the trophoblast in the absence of antiphospholipid antibodies, although combination therapy is the least detrimental by minimizing the adverse increase in growth-regulated oncogene-α. Although the in vitro model is an isolated system and cannot replicate the complex in vivo milieu in antiphospholipid syndrome patients, these findings underscore the need to better understand the effects of our therapies on the inflammatory milieu and to identify better-targeted therapy in the treatment of pregnancies complicated by antiphospholipid syndrome.

As previously described by our group,16 some derangements in angiogenic factor production in antiphospholipid syndrome mimic those seen in pre-eclampsia, such as elevated soluble endoglin. In pre-eclampsia, circulating levels of VEGF and placental growth factor are markedly reduced, whereas placental-derived soluble FMS-like tyrosine kinase-1 and soluble endoglin are elevated.27,30,31 Alterations in the angiogenic factor balance may be associated with the dysfunctional low-capacitance, high-resistance placenta seen with pre-eclampsia. A similar effect is paradoxically induced with exposure to single-agent LMW heparin, with profound increases in soluble FMS-like tyrosine kinase-1 in the basal and antiphospholipid antibodies-induced states. A recent mechanistic study implicates placental heparanase in the regulation of soluble FMS-like tyrosine kinase-1 release.28 LMW heparin also decreased VEGF, further inducing an overall antiangiogenic milieu. The potentially beneficial placental growth factor response may be counteracted by the profound antiangiogenic soluble FMS-like tyrosine kinase-1 response.

These changes in the angiogenic milieu may explain the inability of LMW heparin and ASA to prevent adverse outcomes in late gestation, such as pre-eclampsia or IUGR. Low molecular weight heparin may prevent early loss by altering the inflammatory milieu in antiphospholipid syndrome patients,13 while setting the foundation for impaired placentation by worsening angiogenesis. In the basal in vitro model, mimicking nonantiphospholipid syndrome patients at high-risk for recurrent adverse outcomes, ASA, the current accepted standard of care, did not affect the angiogenic milieu. More importantly, the paradoxical development of an antiangiogenic milieu mirroring that seen in pre-eclampsia speaks to a need for judicious use of LMW heparin in conditions that are not absolute indications for anticoagulation.

Last, trophoblast migration and invasion into spiral arteries is necessary to establish an adequate placental vascular system. We previously reported that antiphospholipid antibodies limit trophoblast migration by reducing IL-6 production.17 Despite unchanged IL-6 levels with LMW heparin therapy, LMW heparin increased basal trophoblast migration, with further improvement when combined with ASA, albeit marginally. This contradictory upregulation of migration indicates that trophoblast migration is likely regulated by a complex network of factors. Possible factors that merit further investigation include the hypoxia-inducible microRNA-21029 or Nodal,32 a member of the transforming growth factor-β superfamily. However, none of the treatments provided protection against antiphospholipid antibodies-induced downregulation of migration.

Although this in vitro model does not fully mimic the complex milieu in vivo, the strength of our system is that it allows for an uncomplicated way to test the actions of the current treatment regimen on the trophoblast, a crucial player in placental health. The use of a monoclonal antihuman β2-GPI antibody, instead of patient-derived polyclonal antiphospholipid antibodies, and the first-trimester trophoblast cell line instead of primary trophoblast cells, because of the large scale of the experiments, should also be noted. However, we believe these are valid alternatives because our previous studies have shown the monoclonal to behave in a similar manner to patient-derived antibodies and the trophoblast cell line to respond to antiphospholipid antibodies similarly to primary first trimester cultures.15,16 Nonetheless, further evaluation of the effects of LMW heparin and ASA on primary trophoblasts from different gestational ages may further shed light on the effects of these medications. Last, LMW heparin was chosen for this model, instead of unfractionated heparin, because LMW heparin is the standard of care in many clinical settings because of ease of administration and improved patient adherence. However, we have found that unfractionated heparin and LMW heparin have similar effects on the trophoblast.15,17

In summary, LMW heparin, ASA, and combination therapy each impart a distinct set of action on the function of human first-trimester trophoblasts, with both beneficial and potentially detrimental cellular effects. Their mixed effect on the antiphospholipid antibodies-induced pathological state may explain the inability of current therapies to fully reverse the detrimental effects of antiphospholipid syndrome and the conflicting data seen in vivo. Our findings highlight the need for additional investigation into the use of heparin and ASA in the treatment of antiphospholipid syndrome-induced pregnancy complications and the need for new targeted therapeutics.

Back to Top | Article Outline

REFERENCES

1. Miyakis S, Lockshin MD, Atsumi T, Branch DW, Brey RL, Cervera R, et al.. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (antiphospholipid syndrome). J Thromb Haemost 2006;4:295–306.

2. Denney JM, Porter TF, Branch DW. Autoimmune Diseases. In: James D, Steer PJ, Weiner CP, Gonik B, editors. High risk pregnancy: Management options. New York (NY): Saunders; 2011. p. 763.

3. Backos M, Rai R, Baxter N, Chilcott IT, Cohen H, Regan L. Pregnancy complications in women with recurrent miscarriage associated with antiphospholipid antibodies treated with low-dose aspirin and heparin. Br J Obstet Gynaecol 1999;106:102–7.

4. Branch DW, Khamashta MA. Antiphospholipid syndrome: Obstetric diagnosis, management, and controversies. Obstet Gynecol 2003;101:1333–44.

5. Stephenson MD, Ballem PJ, Tsang P, Purkiss S, Ensworth S, Houlihan E, et al.. Treatment of antiphospholipid antibody syndrome (antiphospholipid syndrome) in pregnancy: A randomized pilot trial comparing low molecular weight heparin to unfractionated heparin. J Obstet Gynaecol Can 2004;26:729–34.

6. Cohn DM, Goddijn M, Middeldorp S, Korevaar JC, Dawood F, Farquharson RG. Recurrent miscarriage and antiphospholipid antibodies: Prognosis of subsequent pregnancy. J Thromb Haemost 2010;8:2208–13.

7. Farquharson RG, Quenby S, Greaves M. Antiphospholipid syndrome in pregnancy: A randomized, controlled trial of treatment. Obstet Gynecol 2002;100:408–13.

8. Erkan D, Yazici Y, Peterson MG, Sammaritano L, Lockshin MD. A cross-sectional study of clinical thrombotic risk factors and preventive treatments in antiphospholipid syndrome. Rheumatology (Oxford) 2002;41:924–9.

9. Empson M, Lassere M, Craig JC, Scott JR. Recurrent pregnancy loss with antiphospholipid antibody: A systematic review of therapeutic trials. Obstet Gynecol 2002;99:135–44.

10. Pattison NS, Chamley LW, Birdsall M, Zanderigo AM, Liddell HS, McDougall J. Does aspirin have a role in improving pregnancy outcome for women with the antiphospholipid syndrome? A randomized controlled trial. Am J Obstet Gynecol 2000;183:1008–12.

11. Bujold E, Roberge S, Lacasse Y, Bureau M, Audibert F, Marcoux S, et al.. Prevention of preeclampsia and intrauterine growth restriction with aspirin started in early pregnancy: A meta-analysis. Obstet Gynecol 2010;116:402–14.

12. Quenby S, Mountfield S, Cartwright JE, Whitley GS, Vince G. Effects of low-molecular-weight and unfractionated heparin on trophoblast function. Obstet Gynecol 2004;104:354–61.

13. Abrahams VM. Mechanisms of antiphospholipid antibody-associated pregnancy complications. Thromb Res 2009;124:521–5.

14. Bose P, Kadyrov M, Goldin R, Hahn S, Backos M, Regan L, et al.. Aberrations of early trophoblast differentiation predispose to pregnancy failure: Lessons from the anti-phospholipid syndrome. Placenta 2006;27:869–75.

15. Mulla MJ, Brosens JJ, Chamley LW, Giles I, Pericleous C, Rahman A, et al.. Antiphospholipid antibodies induce a pro-inflammatory response in first trimester trophoblast via the TLR4/MyD88 pathway. Am J Reprod Immunol 2009;62:96–111.

16. Carroll TY, Mulla MJ, Han CS, Brosens JJ, Chamley LW, et al.. Modulation of trophoblast angiogenic factor secretion by antiphospholipid antibodies is not reversed by heparin. Am J Reprod Immunol 2011 [Epub ahead of print].

17. Mulla MJ, Myrtolli K, Brosens JJ, Chamley LW, Kwak-Kim JY, Paidas MJ, et al.. Antiphospholipid antibodies limit trophoblast migration by reducing IL-6 production and STAT3 activity. Am J Reprod Immunol 2010;63:339–48.

18. Chamley LW, Konarkowska B, Duncalf AM, Mitchell MD, Johnson PM. Is interleukin-3 important in antiphospholipid antibody-mediated pregnancy failure? Fertil Steril 2001;76:700–6.

19. Chamley LW, Duncalf AM, Konarkowska B, Mitchell MD, Johnson PM. Conformationally altered beta 2-glycoprotein I is the antigen for anti-cardiolipin autoantibodies. Clin Exp Immunol 1999;115:571–6.

20. Yeomans ND. Aspirin: Old drug, new uses and challenges. J Gastroenterol Hepatol 2011;26:426–31.

21. Graham CH, Hawley TS, Hawley RG, MacDougall JR, Kerbel RS, Khoo N, et al.. Establishment and characterization of first trimester human trophoblast cells with extended lifespan. Exp Cell Res 1993;206:204–11.

22. Orendi K, Gauster M, Moser G, Meiri H, Huppertz B. Effects of vitamins C and E, acetylsalicylic acid and heparin on fusion, beta-HCG and PP13 expression in BeWo cells. Placenta 2010;31:431–8.

23. Rand JH, Wu XX, Andree HA, Lockwood CJ, Guller S, Scher J, et al.. Pregnancy loss in the antiphospholipid-antibody syndrome–a possible thrombogenic mechanism. N Engl J Med 1997;337:154–60.

24. Fritchley SJ, Kirby JA, Ali S. The antagonism of interferon-gamma (IFN-gamma) by heparin: Examination of the blockade of class II MHC antigen and heat shock protein-70 expression. Clin Exp Immunol 2000;120:247–52.

25. Johann S, Zoller C, Haas S, Blumel G, Lipp M, Forster R. Sulfated polysaccharide anticoagulants suppress natural killer cell activity in vitro. Thromb Haemost 1995;74:998–1002.

26. Huo Y, Weber C, Forlow SB, Sperandio M, Thatte J, Mack M, et al.. The chemokine KC, but not monocyte chemoattractant protein-1, triggers monocyte arrest on early atherosclerotic endothelium. J Clin Invest 2001;108:1307–14.

27. Venkatesha S, Toporsian M, Lam C, Hanai J, Mammoto T, et al.. Soluble endoglin contributes to the pathogenesis of preeclampsia. Nat Med 2006;12:642–9.

28. Sela S, Natanson-Yaron S, Zcharia E, Vlodavsky I, Yagel S, Keshet E. Local retention compared with systemic release of soluble VEGF receptor-1 are mediated by heparin-binding and regulated by heparanase. Circ Res 2011;108:1063–70.

29. Zhang Y, Fei M, Xue G, Zhou Q, Jia Y, Li L, et al.. Elevated levels of hypoxia-inducible microRNA-210 in preeclampsia: new insights into molecular mechanisms for the disease. J Cell Mol Med 2011 [E-pub ahead of print].

30. Gu Y, Lewis DF, Wang Y. Placental productions and expressions of soluble endoglin, soluble fms-like tyrosine kinase receptor-1, and placental growth factor in normal and preeclamptic pregnancies. J Clin Endocrinol Metab 2008;93:260–6.

31. Maynard SE, Min JY, Merchan J, Lim KH, Li J, Mondal S, et al.. Excess placental soluble fms-like tyrosine kinase 1 (sFlt1) may contribute to endothelial dysfunction, hypertension, and proteinuria in preeclampsia. J Clin Invest 2003;111:649–58.

32. Nadeem L, Munir S, Fu G, Dunk C, Baczyk D, Caniggia I, et al.. Nodal signals through activin receptor-like kinase 7 to inhibit trophoblast migration and invasion: implication in the pathogenesis of preeclampsia. Am J Pathol 2011;189:1177–89.

Cited By:

This article has been cited 2 time(s).

Clinics in Laboratory Medicine
Anticoagulation in Management of Antiphospholipid Antibody Syndrome in Pregnancy
Lockshin, MD
Clinics in Laboratory Medicine, 33(2): 367-+.
10.1016/j.cll.2013.01.001
CrossRef
American Journal of Reproductive Immunology
Management of Women with Recurrent Pregnancy Losses and Antiphospholipid Antibody Syndrome
Kwak-Kim, J; Agcaoili, MSL; Aleta, L; Liao, AH; Ota, K; Dambaeva, S; Beaman, K; Kim, JW; Gilman-Sachs, A
American Journal of Reproductive Immunology, 69(6): 596-607.
10.1111/aji.12114
CrossRef
Back to Top | Article Outline

© 2011 The American College of Obstetricians and Gynecologists

Login

Article Tools

Images

Share