The effect of LMWH (tinzaparin) on coagulation and fibrinolytic activation in pregnant women at risk of thrombosis

The effect and mechanism of low-molecular-weight heparin on the decidualization of stromal cells in early pregnancy

OBJECTIVE

This study aimed to analyze the effect of low-molecular-weight heparin (LMWH) on the decidualization of stromal cells in early pregnancy and explore the effect of LMWH on pregnancy outcomes.

METHODS

Recurrent spontaneous abortion (RSA) mouse model (CBA/J × DBA/2) and normal pregnant mouse model (CBA/J × BALB/c) were established. The female mice were checked for a mucus plug twice daily to identify a potential pregnancy. When a mucus plug was found, conception was considered to have occurred 12 h previously. The pregnant mice were divided randomly into a normal pregnancy control group, an RSA model group, and an RSA + LMWH experimental group (n = 10 mice in each group). Halfway through the 12th day of pregnancy, the embryonic loss of the mice was observed; a real-time quantitative polymerase chain reaction was used to detect the messenger ribonucleic acid (mRNA) expressions of prolactin (PRL) and insulin-like growth factor-binding protein 1 (IGFBP1) in the decidua of the mice. Additionally, the decidual tissues of patients with RSA and those of normal women in early pregnancy who required artificial abortion were collected and divided into an RSA group and a control group. Decidual stromal cells were isolated and cultured to compare cell proliferation between the two groups, and cellular migration and invasion were detected by membrane stromal cells. Western blotting was used to detect the protein expressions of proliferating cell nuclear antigen (PCNA), cyclin D1, matrix metalloproteinase- (MMP) 2, and MMP-7 in stromal cells treated with LMWH.

RESULTS

Compared with the RSA group, LMWH significantly reduced the pregnancy loss rate in the RSA mice (p < 0.05). Compared with the RSA group, the LMWH + RSA group had significantly higher expression levels of PRL and IGFBP1 mRNA (p < 0.01). LMWH promoted the proliferation, migration, and invasion of human decidual stromal cells; compared with the control group, the expression levels of MMP-2, MMP-7, cyclin D1, and PCNA proteins in the decidual stromal cells of the LMWH group increased (p < 0.05).

CONCLUSIONS

The use of LMWH can improve pregnancy outcomes by enhancing the proliferation and migration of stromal cells in early pregnancy and the decidualization of stromal cells.

Thrombin generation post elective caesarean section: effect of low molecular weight heparin

INTRODUCTION

Caesarean section (CS) is a significant risk factor for venous thromboembolism.. Low molecular weight heparin (LMWH) is commonly used for thromboprophylaxis post emergency caesarean delivery. However, no consensus exists regarding LMWH thromboprophylaxis following elective caesarean section. Measures of thrombin formation may indicate the full anticoagulant activity of LMWH in this setting.

MATERIALS AND METHODS

Anti-Xa, tissue factor pathway inhibitor (TFPI), thrombin anti-thrombin complex (TAT) and endogenous thrombin potential (ETP) were measured in twenty healthy women who received 4,500 IU tinzaparin 6 hours post CS (CS1), twenty women who received 4,500 IU tinzaparin at 10-12 hours post delivery (CS2) and twenty women post spontaneous vaginal delivery (SVD).

RESULTS

Prior to initiation of LMWH, TAT levels at 6 hours post delivery were significantly higher in the CS1 and CS2 groups than the SVD group (P<0.002); TAT levels were significantly reduced up to 24 hours post LMWH treatment despite declining anti-Xa levels (P<0.001). In CS1, peak thrombin and ETP were significantly reduced following LMWH prophylaxis (P<0.0001; P<0.002) and reverted to pre-delivery levels 10 hours post LMWH. TFPI levels mirror anti-Xa levels during the 24 hours following LMWH treatment in CS1 group with peak levels coinciding with peak anti-Xa levels 4 hours post injection.

CONCLUSION

In women post caesarean section, anti-Xa levels do not reflect the full anticoagulant effects of LMWH. In-vivo thrombin production (TAT) is effectively reduced even when anti-Xa levels are negligible. LMWH thromboprophylaxis in this healthy cohort of patients appears to have a sustained effect in reducing excess thrombin production post elective caesarean section.

Tinzaparin sodium: a review of its use in the prevention and treatment of deep vein thrombosis and pulmonary embolism, and in the prevention of clotting in the extracorporeal circuit during haemodialysis

Tinzaparin sodium (Innohep) is a low molecular weight heparin (LMWH) that is effective in the prevention and treatment of deep vein thrombosis (DVT) and/or pulmonary embolism (PE), and in maintaining the patency of haemodialysis circuits in adult patients. In terms of preventing DVT and/or PE, therapy with subcutaneous tinzaparin sodium was more effective than oral warfarin and equivalent to subcutaneous enoxaparin sodium in patients undergoing orthopaedic surgery, and did not significantly differ from that of subcutaneous unfractionated heparin (UFH) in patients undergoing general surgery. In the initial therapy of adult patients with DVT and/or PE, subcutaneous tinzaparin sodium was at least as effective as intravenous UFH and did not significantly differ from subcutaneous dalteparin sodium. Various other studies have demonstrated that the long-term efficacy of subcutaneous tinzaparin sodium in the treatment of patients with DVT and/or PE was sustained for a total period of up to 12 months. Tinzaparin sodium was also demonstrated to be effective in maintaining the patency of haemodialysis circuits in adult patients with end-stage renal failure. In clinical studies, tinzaparin sodium was generally well tolerated in the prevention and treatment of DVT and/or PE in adult patients, including in elderly patients, and in patients undergoing haemodialysis. As expected, bleeding complications were the most frequently occurring adverse event. Thus, available data indicate that tinzaparin sodium is a useful option in the prevention and treatment of DVT and/or PE, and in maintaining the patency of haemodialysis circuits in adult patients.