Hirudin ameliorates immunoglobulin A nephropathy by inhibition of fibrosis and inflammatory response.

Immunoglobulin A nephropathy (IgAN) is characterized by mesangial IgA and IgG co-deposition. As the clinical course of IgAN is highly variable, a lot of patients will eventually develop to end-stage renal disease (ESRD) within years. Hirudin, a potent and specific thrombin inhibitor, has been reported to treat IgAN with hematuria, but the mechanism is unclear. Our study aims to explore the potential of hirudin and the underlying mechanism in the treatment of IgAN. The establishment of IgAN model was set up in rats through oral and intravenous immunization with bovine gamma-globulin (BGG). Results suggested that hirudin could reduce the increased level of proteinuria, serum creatinine and urea nitrogen in IgAN models. Besides that, hirudin ameliorated the elevated number of apoptotic bodies and expressions of apoptosis-related proteins (caspase-3 and caspase-9) in IgAN model. The fibrosis indexes (transforming growth factor ß-1 (TGF-ß1), Collagen-IV (CoI-IV) and Fibronectin-1) of kidney were remarkably suppressed in IgAN rats treated with hirudin compared with IgAN rats with no further treatment. IgAN rats exhibited remarkably increased inflammatory factors (IL-1ß, IL-6, and IL-18), while hirudin treatment significantly alleviated these alterations. Moreover, the reduced levels of CD4+CD25+Foxp3+ Treg and CD4+IFN-γ+ Th1/CD4+IL-4+ Th2 could be reversed by hirudin in IgAN model. Furthermore, in the process of IgAN, hirudin could inactivate various pathways (IκBα, NF-κB, TNF-α, and VCAM-1) compared with IgAN model group. Taken together, our study indicated that hirudin could ameliorate IgAN through suppressing fibrosis and inflammatory response. These findings provide a new therapeutic method to treat IgAN.

Standardization of a well-controlled in vivo mouse model of thrombus formation induced by mechanical injury.

OBJECTIVE: Vascular plug formation by mechanical injury that exposes abundant extracellular matrix is an ideal model to mimic thrombus formation. The objective of this study was to standardize our previously established in vivo mouse model of thrombus formation induced by mechanical injury. RESULTS: The mechanical injury was exerted by pinching the abdominal aorta with hemostatic forceps for either 15 (moderate injury) or 60 (severe injury) seconds. Thrombus formation was monitored for 20min in real time using a fluorescent microscope coupled to a CCD camera. In the moderate injury, thrombus formation peaked at approximately 1min after injury and resolved within 3min, with the mean AUC (area under the curve) of 165.2±17.29mm(2), whereas a larger thrombus was observed upon the severe injury, with the mean AUC of 600.5±37.77mm(2). Using scanning electron microscopy and HE staining, a complete deformation of the endothelium in the moderate injury model and the exposure of the media in the severe injury model were observed. The model was also evaluate for its application on the effects of antithrombotic drugs targeting GP IIb-IIIa (eptifibatide), ADP receptor P2Y1 (MRS2500) and P2Y12 (clopidogrel), and thrombin (hirudin) on thrombus formation. CONCLUSIONS: We have improved a vascular injury model with optimal reproducibility and feasibility that allows evaluating the effect of anti-thrombotic drugs on thrombus formation in vivo.

[Analysis of the medicinal leech effects on the state of arterial functions of aged probationers, using hardwarily software system "Angioscan-01"].

The state of elderly patients arterial wall after the putting of one medicinal leech was estimated by use hardwarily software system "Angioscan-01". There was compared the effect of one medicinal leech on indicators of vasomotor function of endothelium of small resistance arteries and of middle arteries of muscular type. Stickiness index and augmentation index were determined in order to evaluate the medicinal leech effect on the rigidity state of arterial wall. It is shown that the putting of one leech stimulates the improving of endothelium vasomotor function and of normalization arterial wall stickiness. It is supposed the participation in this process the secretion of the medicinal leech salivary cells, which, as has been shown recently, is able to activate e-NOS and n-NOS in human endothelium culture (HUVEC) and increase NO level. Elevation of share stress during occlusion test is also stimulated NO production in vascular endothelium.

Inhibitory effect of r-hirudin variant III on streptozotocin-induced diabetic cataracts in rats.

The in vivo inhibitory effect of r-hirudin variant III (rHV3) on streptozotocin (STZ)-induced diabetic cataracts in rats was investigated. SD-rats were firstly made diabetic by a single intraperitoneal injection of 2% (W/V) STZ (65 mg/kg). Two weeks later, cataract formation was examined by slit lamp microscope, and the cataracted animals were randomly grouped. The animals in the treated groups received rHV3 drops administration to the eyes with various doses. After 4 weeks treatment, the animals were sacrificed to evaluate the biochemical changes of aldose reductase (AR), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) levels in the eye lens. Meanwhile, the cataract progression was monitored by slit lamp microscope. As a result, rHV3 drops treatment significantly increased the activities of SOD and GSH-Px in the lens in a dose-dependent manner, whereas AR activity and MDA level in the lens were dramatically decreased. Also, the morphological observation further confirmed the inhibition of the development of STZ-induced diabetic cataracts by the rHV3 drops treatment. Thus, our data suggest that rHV3 drops are pharmacologically effective for the protection against STZ-induced diabetic cataracts in rats.

Medicinal leech therapy on head and neck patients: a review of literature and proposed protocol.

OBJECTIVES: To this day, a standardized protocol for medicinal leech therapy does not exist. The purpose of this article was to review literature in the hope of proposing a unified, coherent, feasible, and safe protocol for using medicinal leeches when warranted. STUDY DESIGN: A literature search was conducted in the following databases: PubMed, MDConsult, The Cochrane Library, OMIM, and Google. This was supplemented by a search for selected authors. Keywords used were medicinal leech therapy, leech therapy, leeching, replantation, thromboembolism, venous congestion, Hirudo medicinalis, Hirudotherapy, leech protocol, and Hirudo protocol. RESULTS: Based on titles and abstracts, 26 articles and 1 Web site were identified. CONCLUSIONS: Leech therapy can be an excellent alternative for the treatment of venous congestion in free flaps, pedicled flaps, and replanted tissues. Psychological precounseling, antibiotic therapy, number of leeches to be used, length of therapy, and laboratory checks should be taken into consideration before initiating therapy.

[Anticoagulation with hirudin for repeat cardiac surgery in a patient with heparin induced thrombocytopaenia]. / Hirudinnal végzett alvadásgátlás heparin kiváltotta thrombocytopeniában harmadik szívmutét során.

UNLABELLED: The authors present the case of a patient with heparin induced thrombocytopaenia who needed anticoagulation during the perioperative period of a third repeat cardiac operation without transfusions. Prostacyclin pretreatment was contraindicated because of critical aortic stenosis, heparinoids could not have been used due to necessity of postoperative anticoagulation. Recombinant hirudin was applied and its effect was monitored with ekarin coagulation time. Hirudin anticoagulation was continued until the proper INR was reached in the postoperative period. There were no intra- and postoperative complications detected, and there was no need for transfusion either. On his long-term follow-up, 6.5 years after the last cardiac surgery the patients was feeling well and had no complaints. CONCLUSION: Open heart operation of a patient with heparin induced thrombocythopenia can be performed safely by total anticoagulation with lepirudin if it is conducted by ecarin clotting time.

Anticoagulation options for patients with heparin-induced thrombocytopenia requiring renal support in the intensive care unit.

World wide, heparins are the most commonly used anticoagulants for renal replacement therapy (RRT). In the intensive care unit (ICU) keeping the RRT circuit patent is more difficult than during routine outpatient hemodialysis, as ICU patients typically have sepsis and/or inflammation resulting in activation of the procoagulant pathways, with reduced antithrombin. One important cause of repeated RRT circuit clotting is heparin-induced thrombocytopenia (HIT), which should not be overlooked in patients with a reduced platelet count. If HIT is clinically suspected then all heparins should be withdrawn, and the patient systemically anticoagulated with either a direct thrombin inhibitor, such as argatroban and/or hirudin, or the heparinoid danaparoid. The availability and licensing of these alternative anticoagulants varies from country to country. Argatroban has to be continuously infused, which is an advantage for continuous RRT, but not for intermittent RRT, and can be monitored by activated partial thromboplastin time. Hirudin has a prolonged half life, which is extended by hirudin antibodies, and requires specialist monitoring to prevent over anticoagulation. Although the half life of danaparoid is increased in renal failure, it can be given as boluses for intermittent and continuous RRT, or by continuous infusion during continuous RRT, but requires factor Xa monitoring.

Thrombin in ischemic neuronal death.

Thrombin plays a role in cerebral ischemia as rats subjected to focal cerebral ischemia were protected by the intracerebral injection of hirudin, a selective thrombin inhibitor. To separate the roles of thrombin in cell death and in coagulation, we have used an in vitro approach to test the effect of hirudin and of protease nexin-1 (PN-1), a cerebral thrombin inhibitor, on neuronal ischemia. Rat organotypic hippocampal slice cultures were subjected to oxygen (5%) and glucose (1 mmol/L) deprivation (OGD) during 30 min. Hirudin or PN-1 administered after OGD significantly prevented neuronal death in the CA1 region. After 24 h, there was a marked increase in thrombin immunoreactivity on Western blots. Thrombin therefore contributes to ischemic damage in neural tissue in vitro.

Protease-activated receptor-1 and platelet-derived growth factor in spinal cord neurons are implicated in neuropathic pain after nerve injury.

Recently, it has been reported that both thrombin-sensitive protease-activated receptor 1 (PAR-1) and platelet-derived growth factor (PDGF) are present not only in platelets, but also in the CNS, which indicates that they have various physiological functions. In this study, we evaluated whether PAR-1/PDGF in the spinal cord could contribute to the development of a neuropathic pain-like state in mice. Thermal hyperalgesia and tactile allodynia induced by sciatic nerve ligation were significantly suppressed by repeated intrathecal injection of hirudin, which is characterized as a specific and potent thrombin inhibitor. Furthermore, a single intrathecal injection of thrombin produced long-lasting hyperalgesia and allodynia, and these effects were also inhibited by hirudin in normal mice. In nerveligated mice, the increase in the binding of [35S]GTPgammaS to membranes of the spinal cord induced by thrombin and PAR-1-like immunoreactivity (IR) in the spinal cord were each greater than those in sham-operated mice. Thermal hyperalgesia and tactile allodynia induced by sciatic nerve ligation were also suppressed by repeated intrathecal injection of either the PDGF alpha receptor (PDGFRalpha)/Fc chimera protein or the PDGFR-dependent tyrosine kinase inhibitor AG17 [(3,5-di-tert-butyl-4-hydroxybenzylidene)-malononitrile]. Moreover, thermal hyperalgesia and tactile allodynia induced by thrombin in normal mice were virtually eliminated by intrathecal pretreatment with PDGFRalpha/Fc. In immunohistochemical studies, PAR-1-like IR-positive cells in the spinal dorsal horn were mostly colocated on PDGF-like IR-positive neuronal cells. These data provide novel evidence that PAR-1 and PDGF-A-mediated signaling pathway within spinal cord neurons may be directly implicated in neuropathic pain after nerve injury in mice.

Heparin-induced thrombocytopenia in the cardiovascular patient: diagnostic and treatment guidelines.

Heparin-induced thrombocytopenia/thrombosis is an immunologic reaction to unfractionated heparin characterized by thrombocytopenia, platelet activation and thrombosis. A high index of suspicion is required for timely diagnosis and treatment. Treatment is complex and outcome maybe less then satisfactory.

Intermittent hirudin versus continuous heparin for anticoagulation in continuous renal replacement therapy.

BACKGROUND: Besides possible bleeding complications a further problem in anticoagulation during continuous renal replacement therapy (CRRT) is the development of heparin-induced thrombocytopenia type II (HIT II) where further anticoagulation with heparin is contraindicated. The application of continuous hirudin as alternative for heparin caused bleeding complications by comparable filter efficacy. Aim of this prospective-controlled pilot study was to compare the efficacy and safety of intermittent hirudin and continuous heparin for anticoagulation during CRRT in critically ill patients. METHODS: 26 patients receiving CRRT were randomly allocated to two groups: Heparin group (14 patients): continuous administration of 250 IU/h heparin, dose was adjusted in 125 IU/h steps with a targeted activated clotting time (ACT) of 180-210 s. Hirudin group (12 patients): initial bolus application of 2-2-5 microg/kg hirudin, dose was adjusted in 2 microg/kg bolus steps with a targeted ecarin clotting time (ECT) >80 s. Observation time was 96 hours. RESULTS: Measured filter run time was virtually longer for heparin. No bleeding complications were observed in the hirudin group, two bleeding complications in the heparin group. CONCLUSIONS: Intermittent hirudin can be used safely for anticoagulation in CRRT. However, the in tendency better filter survival for heparin elucidates the need for further investigations to find the right dosage equilibrium between filter clotting and bleeding complications.

Bivalent direct thrombin inhibitors: hirudin and bivalirudin.

Hirudin derivatives (e.g. lepirudin, desirudin) and hirudin analogues (e.g. bivalirudin) are bivalent direct thrombin inhibitors; that is, they bind to two distinct sites on thrombin-its active (catalytic) site and its fibrinogen-binding site (exosite 1). These bivalent binding properties contribute to their high affinity and high specificity for thrombin. This review compares the pharmacological properties of these agents, and describes studies of their efficacy and safety in diverse clinical settings such as immune heparin-induced thrombocytopenia, postoperative antithrombotic prophylaxis, and treatment of acute coronary syndrome. Certain disadvantages of hirudin, such as its predominant renal excretion and immunogenicity, have been overcome through development of the hirudin analogue, bivalirudin. Compared with hirudin derivatives, bivalirudin exhibits a shorter half-life (25 vs 80 minutes), predominant non-renal (enzymic) metabolism, and low immunogenicity. Further work is required to define the scope of clinical thrombosis problems that could benefit from these novel agents.

Thrombin, a mediator of neurotoxicity and memory impairment.

Thrombin has been found in neuritic plaques in Alzheimer's disease (AD). Also, traumatic brain injury, where neurons are exposed to high thrombin levels, is associated with an increased incidence of AD. Our objective was to determine the effects of thrombin administered in vivo on cognitive function and neuropathology. Rats were trained using a radial eight-arm maze and then thrombin (25 or 100 nM, 0.25 microl/h, 28 days) or vehicle was delivered via intracerebroventricular infusion. Animals that received 100 nM thrombin demonstrated cognitive impairments including deficits in reference memory and an increase in task latency. Also, significant neuropathology was detected in these animals such as enlargement of cerebral ventricles, an increased number of TUNEL-positive cells, astrogliosis, and an increase in the immunoreactivity for phosphorylated neurofilament, and apolipoprotein-E fragments. Thrombin-induced changes in cognitive function and ventricular enlargement were inhibited by hirudin. These findings demonstrate that thrombin is a mediator of neurotoxicity and cognitive deficits and suggest that inhibition of thrombin may be a treatment strategy for AD- or head trauma-associated cognitive deficits.

Alternative methods of anticoagulation for dialysis-dependent patients with heparin-induced thrombocytopenia.

Dialysis patients who are continually exposed to heparin are at risk for heparin-induced thrombocytopenia (HIT). Heparin-induced antibodies have been reported to occur in 0-12% of hemodialysis (HD) patients. The diagnosis or suspicion of HIT in this patient population requires careful confirmation of the diagnosis and substitution of heparin with an alternate anticoagulant for dialysis. Alternate agents such as the direct thrombin inhibitors (hirudin and argatroban) are available, but careful dosing and monitoring of the anticoagulant effect are required. Despite careful dosing, hemorrhagic complications have occurred with these agents. Unfortunately there are limited options for treatment of hemorrhagic complications and no specific antidotes are available for the direct thrombin inhibitors. In this report the currently available alternatives to heparin for dialysis, including dosing and monitoring recommendations, are reviewed.