Intravenous Administration of Low-Molecular-Weight Heparin

End-on PEGylation of heparin: Effect on anticoagulant activity and complexation with protamine

Heparin is the most common anticoagulant used in clinical practice but shows some downsides such as short half-life (for the high molecular weight heparin) and secondary effects. On the other hand, its low molecular weight analogue cannot be neutralized with protamine, and therefore cannot be used in some treatments. To address these issues, we conjugated polyethylene glycol (PEG) to heparin reducing end (end-on) via oxime ligation and studied the interactions of the conjugate (Hep-b-PEG) with antithrombin III (AT) and protamine. Isothermal titration calorimetry showed that Hep-b-PEG maintains the affinity to AT. Dynamic light scattering demonstrated that the Hep-b-PEG formed colloidal stable nanocomplexes with protamine instead of large multi-molecular aggregates, associated with heparin side effects. The in vitro (human plasma) and in vivo experiments (Sprague Dawley rats) evidenced an extended half-life and higher anticoagulant activity of the conjugate when compared to unmodified heparin.

Efficacy of Low Molecular Weight Heparin in Preventing Perinatal Venous Thrombosis: A Meta-Analysis

Background

There have been controversies about the preventive effect of low molecular weight heparin (LMWH) on venous thrombosis (VT) in the perinatal period. This study is aimed at exploring the effectiveness of LMWH in preventing perinatal VT through meta-analysis.

Methods

Databases such as CNKI, China Biology Medicine disc (CBMdisc), Wanfang, PubMed, MEDLINE, Embase, and Central were searched. Inclusion criteria were as follows: (1) subjects: women at high risk of perinatal VT; (2) experimental group and control group; (3) intervention measures: the experimental group was given LMWH, while the control group was given placebo or standard heparin or physical therapy; (4) outcomes: perinatal VT events or bleeding events; and (5) randomized controlled trials (RCTs). Jadad scale was used to evaluate the literature quality. The Mantel-Haenszel method was used to calculate the odds ratio (OR) and 95% confidence interval (CI). The chi-square test was used to analyze the heterogeneity of the included literature. Subgroup analysis was used to explore the source of heterogeneity. Publication bias was evaluated via funnel plot and Egger test.

Results

The incidence of perinatal VT in the LMWH group was lower than that in the control group (OR = 0.16, 95% CI (0.08, 0.32), P < 0.00001). There was no heterogeneity among literatures (P = 0.77, I² = 0%) and no publication bias. The incidence of postpartum VT in the LMWH group was lower than that in the control group (OR = 0.14, 95% CI (0.07, 0.30), P < 0.00001). There was no heterogeneity among literatures (P = 0.69, I² = 0%) and no publication bias. The incidence of perinatal bleeding in the LMWH group was higher than in the control group (OR = 1.72, 95% CI (1.06, 2.77), P = 0.03). There was no heterogeneity among literatures (P = 0.25, I² = 26%) and no publication bias.

Conclusion

LMWH can reduce the incidence of perinatal VT in high-risk women but increase the risk of bleeding. The use of LMWH to prevent perinatal VT should be closely monitored.

Purification, biochemical characterization and fibrinolytic potential of proteases produced by bacteria of the genus Bacillus: a systematic literature review

Thrombosis is a hematological disorder characterized by the formation of intravascular thrombi, which contributes to the development of cardiovascular diseases. Fibrinolytic enzymes are proteases that promote the hydrolysis of fibrin, promoting the dissolution of thrombi, contributing to the maintenance of adequate blood flow. The characterization of new effective, safe and low-cost fibrinolytic agents is an important strategy for the prevention and treatment of thrombosis. However, the development of new fibrinolytics requires the use of complex methodologies for purification, physicochemical characterization and evaluation of the action potential and toxicity of these enzymes. In this context, microbial enzymes produced by bacteria of the Bacillus genus are promising and widely researched sources to produce new fibrinolytics, with high thrombolytic potential and reduced toxicity. Thus, this review aims to provide a current and comprehensive understanding of the different Bacillus species used for the production of fibrinolytic proteases, highlighting the purification techniques, biochemical characteristics, enzymatic activity and toxicological evaluations used.

Slow versus fast subcutaneous heparin injections for prevention of bruising and site pain intensity

BACKGROUND

Heparin is an anticoagulant medication that is usually injected subcutaneously. Subcutaneous administration of heparin may result in complications such as bruising, haematoma, and pain at the injection site. One of the factors that may affect pain, haematoma, and bruising is injection speed. Several studies have been carried out to determine if speed of injection affects the amount of pain and bruising where the injection is given; however, the results of these studies have differed, and study authors have not reached a clear final conclusion. This is the second update of a review first published in 2014.

OBJECTIVES

To assess the effects of duration (speed) of subcutaneous heparin injection on pain and bruising at the injection site in people admitted to hospitals or clinics who require treatment with unfractionated heparin (UFH) or low molecular weight heparin (LMWH). We also looked at haematoma at the injection site.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 22 June 2020. We undertook reference checking of included studies to identify additional studies.

SELECTION CRITERIA

We searched for randomised controlled trials (RCTs) comparing the effects of different durations of subcutaneous injection of heparin on pain, bruising, and haematoma at the injection site.

DATA COLLECTION AND ANALYSIS

For this update, two review authors independently selected studies and extracted data via Covidence software and assessed methodological quality using Cochrane's risk of bias tool. The primary outcomes of interest were pain intensity at injection site and size and incidence of bruising. The secondary outcomes of interest were size and incidence of haematoma at injection site. We calculated the odds ratio (OR), mean difference (MD), or standardised mean difference (SMD) with corresponding 95% confidence intervals (CIs). We assessed the certainty of the evidence using GRADE criteria.

MAIN RESULTS

We identified one new study for this update, resulting in a total of five included studies with 503 participants who received subcutaneous injections of LMWH into the abdomen. Given the nature of the intervention, it was not possible to blind participants and caregivers (personnel) in any of the included studies. Two studies described blinding of outcome assessors. Overall, the methodological quality of included studies was moderate. The duration of the fast injection was 10 seconds, and the duration of the slow injection was 30 seconds in all included studies. Four studies reported site pain intensity after each injection at different time points. Two studies assessed site pain intensity immediately after each injection; meta-analysis showed no evidence of a difference in site pain intensity immediately after slow injection when compared to fast injection (MD -1.52, 95% CI -3.56 to 0.53; 140 participants; low-certainty evidence). Meta-analysis of three studies indicated that site pain intensity may be slightly reduced 48 hours after the slow heparin injection compared to fast injection (MD -1.60, 95% CI -2.69 to -0.51; 103 participants; low-certainty evidence). Five studies assessed bruise size at 48 hours, and two studies assessed bruise size at 60 hours. Meta-analysis showed there may be a reduction in bruise size 48 hours (SMD -0.54, 95% CI -1.05 to -0.02; 503 participants; 5 studies; very low-certainty evidence) and 60 hours (SMD -0.49, 95% CI -0.93 to -0.06; 84 participants; 2 studies; low-certainty evidence) after slow injection compared to fast injection. There was no evidence of a difference in bruise size 72 hours after slow injection compared to fast injection (SMD -0.27, 95% CI -0.61 to 0.06; 140 participants; 2 studies; low-certainty evidence). Three studies evaluated incidence of bruising and showed there may be a reduction in bruise incidence 48 hours (OR 0.39, 95% CI 0.26 to 0.60; 444 participants; low-certainty evidence) and 60 hours (OR 0.25, 95% CI 0.10 to 0.65; 84 participants; 2 studies; low-certainty evidence) after slow injection compared to fast injection. We downgraded the certainty of the evidence due to risk of bias concerns, imprecision, and inconsistency. None of the included studies measured size or incidence of haematoma.

AUTHORS' CONCLUSIONS

Administering medication safely and enhancing patient comfort are the main aims of clinical nurses. In this review, we identified five RCTs that evaluated the effect of subcutaneous heparin injection duration on pain intensity, bruise size and incidence. We found that pain may be slightly reduced 48 hours after slow injection. Similarly, there may be a reduction in bruise size and incidence after slow injection compared to fast injection 48 and 60 hours postinjection. We downgraded the certainty of the evidence for all outcomes to low or very low due to risk of bias concerns, imprecision, and inconsistency. Accordingly, new trials with a more robust design, more participants, and a focus on different injection speeds will be useful in strengthening the certainty of the available evidence.