Heparin, urokinase, and ancrod alter neutrophil function

Heparin, Heparan Sulphate and Sepsis: Potential New Options for Treatment

Sepsis is a life-threatening hyperreaction to infection in which excessive inflammatory and immune responses cause damage to host tissues and organs. The glycosaminoglycan heparan sulphate (HS) is a major component of the cell surface glycocalyx. Cell surface HS modulates several of the mechanisms involved in sepsis such as pathogen interactions with the host cell and neutrophil recruitment and is a target for the pro-inflammatory enzyme heparanase. Heparin, a close structural relative of HS, is used in medicine as a powerful anticoagulant and antithrombotic. Many studies have shown that heparin can influence the course of sepsis-related processes as a result of its structural similarity to HS, including its strong negative charge. The anticoagulant activity of heparin, however, limits its potential in treatment of inflammatory conditions by introducing the risk of bleeding and other adverse side-effects. As the anticoagulant potency of heparin is largely determined by a single well-defined structural feature, it has been possible to develop heparin derivatives and mimetic compounds with reduced anticoagulant activity. Such heparin mimetics may have potential for use as therapeutic agents in the context of sepsis.

Batroxobin in combination with anticoagulation may promote venous sinus recanalization in cerebral venous thrombosis: A real-world experience

Aims

The objective of this study was to evaluate cerebral venous recanalization with magnetic resonance black‐blood thrombus imaging (MRBTI) in patients with cerebral venous thrombosis (CVT) who underwent batroxobin treatment in combination with anticoagulation.

Methods

A total of 31 CVT patients were enrolled in this real‐world registry study. The patients were divided into batroxobin (n = 21) and control groups (n = 10). In addition to the same standard anticoagulation as in the control group, patients in the batroxobin group underwent intravenous batroxobin for a total of three times.

Results

In the batroxobin group compared with the control group, we found better odds of recanalization degree [adjusted OR (95%CI) of 8.10 (1.61‐40.7)] and segment‐stenosis attenuation [adjusted OR (95%CI) of 4.48 (1.69‐11.9)] with batroxobin treatment. We further noted a higher ratio of patients with the attenuation of stenosis [adjusted OR (95%CI) of 26.4 (1.10‐635)]; as well as a higher ratio of segments with stenosis reversion [adjusted OR (95%CI) of 4.52 (1.48‐13.8)]. However, neurological deficits between the two groups showed no statistical difference at 90‐day follow‐up (P > 0.05).

Conclusions

Batroxobin may promote venous sinus recanalization and attenuate CVT‐induced stenosis. Further randomized study of this promising drug may be warranted to better delineate the amount of benefit.

The efficacy and safety of Batroxobin in combination with anticoagulation on cerebral venous sinus thrombosis

Cerebral venous sinus thrombosis (CVST) is an uncommon subtype of stroke with highly variable clinical presentation. Although anticoagulation with heparin and/or warfarin remains the standard treatment for CVST, treatment failure is still common. This study aims to evaluate the safety and efficacy of Batroxobin in combination with anticoagulation on CVST control. In this retrospective study, a total of 61 CVST patients were enrolled and divided into Batroxobin (n = 23) and control (n = 38) groups. In addition to the same standard anticoagulation in control, patients in the treatment group received Batroxobin 5 BU intravenous infusion (10 BU for the first time) every other day, for a total of three infusions. A higher recanalization rate was found in Batroxobin group (adjusted OR [95% CI] of 2.5 [1.1-5.0], p = 0.028) compared to the control group, especially in patients with high levels of fibrinogen (adjusted OR [95% CI] of 4.7 [1.4-16.7], p = 0.015). Statistically significant differences between the two groups were seen regarding the levels of thrombin time, fibrinogen and D-dimer at each cut-off time point (all p < 0.01). Compared with baseline, NIHSS scores at discharge showed significant improvement in the Batroxobin group [0(0, 4.25)-5(2, 11), p = 0.036]. No significant difference in mRS scores was found between the two groups at discharge or at 6-month outpatient follow-up (all p > 0.05). Additionally, Batroxobin did not increase the risk of intracranial hemorrhage. We conclude that Batroxobin is a potentially safe and effective adjunct therapeutic agent promoting CVST recanalization especially in patients with high level of fibrinogen.

Heparin and related drugs: beyond anticoagulant activity

Heparin has been widely used as an anticoagulant for more than 80 years. However, there is now considerable evidence that heparin also possesses anti-inflammatory activity, both experimentally and clinically. Importantly in many instances, the anti-inflammatory actions of heparin are independent of anticoagulant activity raising the possibility of developing novel drugs based on heparin that retain the anti-inflammatory activity. Heparin exhibits anti-inflammatory activities via a variety of mechanisms including neutralization of cationic mediators, inhibition of adhesion molecules, and the inhibition of heparanase, all involved in leukocyte recruitment into tissues. It is anticipated that furthering our understanding of the anti-inflammatory actions of heparin will lead to the development of novel anti-inflammatory drugs for a variety of clinical indications.

Non-anticoagulant effects of heparin: an overview

Heparin has long been known to possess biological effects that are unrelated to its anticoagulant activity. In particular, much emphasis has been placed upon heparin, or novel agents based upon the heparin template, as potential anti-inflammatory agents. Moreover, heparin has been reported to possess clinical benefit in humans, including in chronic inflammatory diseases and cancer, that are over and above the expected effects on blood coagulation and which in many cases are entirely separable from this role. This chapter aims to provide an overview of the non-anticoagulant effects that have been ascribed to heparin, from those involving the binding and inhibition of specific mediators involved in the inflammatory process to effects in whole system models of disease, with reference to the effects of heparin that have been reported to date in human diseases.

Experimental intracerebral hemorrhage in rats. Magnetic resonance imaging and histopathological correlates

BACKGROUND AND PURPOSE

Intracerebral hemorrhage is associated with a considerable proportion of strokes and head injuries. The mechanism of brain cell injury associated with hemorrhage may be different from that due to pure ischemia. Therefore, it is essential that models of intracerebral hemorrhage be developed and well characterized. The purpose of this study was to obtain high-field MR images of rat brain at progressive times after induction of intracerebral hemorrhage and to correlate the images with behavior and histological evolution.

METHODS

Intracerebral hemorrhage was induced in rats by injection of bacterial collagenase and heparin into the caudate nucleus. Histopathological changes and corresponding MR images were studied from 30 minutes to 3 weeks after injection. Behavioral changes were also followed for 3 weeks.

RESULTS

Histological correlation showed that MR is capable of resolving the accumulation and degeneration of the hematoma, a centripetal wave of neutrophils infiltrating from the surrounding tissue beginning at 12 hours, and centripetal invasion of macrophages beginning at 48 hours. Widespread white matter edema was clearly evident on MR images for 1 week after the hemorrhage. Medium-sized striatal neurons were lost in the tissue surrounding the hematoma. Behavioral improvement was rapid during resolution of the edema but incomplete at 3 weeks.

CONCLUSIONS

MR images correlate very well with histological changes in this experimental model of intracerebral hemorrhage and can therefore be used to follow changes due to drug treatments in vivo. The intense neutrophilic response to this lesion may contribute to neuronal injury at the periphery of the hematoma.

Inhibition of superoxide production in human neutrophils by combinations of heparin and thrombolytic agents

OBJECTIVE

To investigate the effect of heparin and thrombolytic agents on superoxide generation by human neutrophils, as inhibition of superoxide production may have a role in reducing ischaemia and reperfusion injury.

METHODS

Neutrophil superoxide production stimulated by phorbol myristate acetate (PMA), opsonised zymosan, or formyl methionyl leucyl phenylalanine (FMLP) was measured as the superoxide dismutase inhibitable reduction of acetyl ferricytochrome c by a microtitre plate technique.

RESULTS

Heparin, at concentrations of 0.5-500 U/ml, caused a gradual inhibition of superoxide production stimulated by PMA, opsonised zymosan, or FMLP. Tissue plasminogen activator was more potent than heparin in inhibiting superoxide production induced by opsonised zymosan or FMLP, but it did not affect the activity stimulated by PMA. Streptokinase or urokinase had no effect on superoxide production. When heparin was used in combination with tissue plasminogen activator, streptokinase, or urokinase at their therapeutic concentrations there was a significant inhibition of superoxide generation (70%, 30%, and 25%, respectively). The therapeutic concentrations of tissue plasminogen activator alone caused a reduction of 40% of neutrophil superoxide production. When tissue plasminogen activator and streptokinase were both added to neutrophils, however, a synergistic inhibition of 80% was achieved.

CONCLUSIONS

The inhibition of super oxide generation by these drug combinations may explain the limited inflammatory response and reduction of reperfusion injury observed in patients receiving thrombolytic treatment.