In vitro and in vivo venom-inhibition assays identify metalloproteinase-inhibiting drugs as potential treatments for snakebite envenoming by Dispholidus typus

Snakebite envenoming affects more than 250,000 people annually in sub-Saharan Africa. Envenoming by Dispholidus typus (boomslang) results in venom induced consumption coagulopathy, whereby highly abundant prothrombin-activating snake venom metalloproteinases (SVMPs) consume clotting factors and deplete fibrinogen. The only available treatment for D. typus envenoming is the monovalent SAIMR Boomslang antivenom. Treatment options are urgently required because this antivenom is often difficult to source and, at $6,000/vial, typically unaffordable for most snakebite patients. We therefore investigated the in vitro and in vivo preclinical efficacy of four SVMP inhibitors to neutralise the effects of D. typus venom; the matrix metalloproteinase inhibitors marimastat and prinomastat, and the metal chelators dimercaprol and DMPS. The venom of D. typus exhibited an SVMP-driven procoagulant phenotype in vitro. Marimastat and prinomastat demonstrated equipotent inhibition of the SVMP-mediated procoagulant activity of the venom in vitro, whereas dimercaprol and DMPS showed considerably lower potency. However, when tested in preclinical murine models of envenomation, DMPS and marimastat demonstrated partial protection against venom lethality, demonstrated by prolonged survival times of experimental animals, whereas dimercaprol and prinomastat failed to confer any protection at the doses tested. The results presented here demonstrate that DMPS and marimastat show potential as novel small molecule-based therapeutics for D. typus snakebite envenomation. These two drugs have been previously shown to be effective against Echis ocellatus venom induced consumption coagulopathy (VICC) in preclinical models, and thus we conclude that marimastat and DMPS may be valuable early intervention therapeutics to broadly treat VICC following snakebite envenoming in sub-Saharan Africa.

Hypercoagulation detected by routine and global laboratory hemostasis assays in patients with infective endocarditis

Background Coagulation system is heavily involved into the process of infective endocarditis (IE) vegetation formation and can facilitate further embolization. In this study we aimed to assess the coagulation and platelet state in IE implementing a wide range of standard and global laboratory assays. We also aim to determine whether prothrombotic genetic polymorphisms play any role in embolization and mortality in IE patients. Methods 37 patients with IE were enrolled into the study. Coagulation was assessed using standard coagulation assays (activated partial thromboplastin time (APTT), prothrombin, fibrinogen, D-dimer concentrations) and integral assays (thromboelastography (TEG) and thrombodynamics (TD)). Platelet functional activity was estimated by flow cytometry. Single nuclear polymorphisms of coagulation system genes were studied. Results Fibrinogen concentration and fibrinogen-dependent parameters of TEG and TD were increased in patients indicating systemic inflammation. In majority of patients clot growth rate in thrombodynamics was significantly shifted towards hypercoagulation in consistency with D-dimers elevation. However, in some patients prothrombin, thromboelastography and thrombodynamics were shifted towards hypocoagulation. Resting platelets were characterized by glycoprotein IIb-IIIa activation and degranulation. In patients with fatal IE, we observed a significant decrease in fibrinogen and thrombodynamics. In patients with embolism, we observed a significant decrease in the TEG R parameter. No association of embolism or mortality with genetic polymorphisms was found in our cohort. Conclusions Our findings suggest that coagulation in patients with infective endocarditis is characterized by general hypercoagulability and platelet pre-activation. Some patients, however, have hypocoagulant coagulation profile, which presumably can indicate progressing of hypercoagulation into consumption coagulopathy.

Kasabach Merritt syndrome in a 28-year-old female: A strange case report

Kasabach Merritt syndrome (KMS) is a rare disease in which a benign vascular tumor that is hemangioma grows rapidly, entraps red blood cells, platelets, and coagulation factors leading to activation of coagulation cascade resulting in life-threatening disseminated intravascular coagulation and microangiopathic hemolytic anemia. KMS affects newborns and infants. Rarely can affect older children and adults with only a few cases reported in the existing literature. Clinically patients present with large cutaneous hemangioma usually involving the extremities however visceral organs may be involved in some cases along with anemia, thrombocytopenia, coagulopathy, and bleeding. We report a case of KMS in a 28-year-old female who presented with bilateral subdural hematoma, thrombocytopenia, and consumption coagulopathy. She was given seven days course of methylprednisolone to which she responded well.

Case Report: Rotational Thromboelastometry in Taipan Envenomation

Venom-induced consumption coagulopathy (VICC) is one of the most dangerous syndromes caused by snake envenomation and can be caused by several snake species worldwide, including the Australian coastal taipan. Rotational thromboelastometry (ROTEM) provides real-time point-of-care information on all stages of clot formation; however, it has yet to be formally evaluated in the assessment of VICC. We report three cases of Taipan envenomation causing VICC and the associated ROTEM results. The implications for future use of ROTEM in the assessment, management, and further research of VICC are discussed.

Splenomegaly development and disseminated intravascular coagulation syndrome in acute canine babesiosis

Disseminated intravascular coagulation (DIC) syndrome is the main defining process in the pathogenetic axis of complications in canine babesiosis. The involvement of the spleen with further irreversible changes in the organ largely determines the severity of the animal’s condition after spontaneous babesiosis. The work presented here aimed to determine the role of the DIC syndrome as a triggering factor for lesions of the spleen. Clinical and laboratory studies (haematological, biochemical, hemodynamic) have been carried out. Pathological studies of the removed spleen were carried out by histological methods using universal and specific staining. After suffering acute spontaneous babesiosis, the development of hypersplenism and splenomegaly was found in dogs. The diagnosis was confirmed haematologically by the detected cytopenia, normochromic type anaemia. An additional parameter was a significantly increased erythrocyte sedimentation rate. The biochemical profile indicated the development of bilirubinaemia due to the conjugated fraction, hyperfermentation of transaminases, hypoalbuminemia, which reflected the development of hepatitis and liver failure. Markers of DIC syndrome in laboratory studies are represented by reliable hypofibrinogenemia, increased level of fibrinogen/fibrin degradation products, including D-dimer, and soluble fibrin monomer complexes. The multidirectional indices of coagulation tests (activated partial thromboplastin and prothrombin time) made it possible to classify the stage of “consumption coagulopathy” of the DIC syndrome. The haemodynamic parameters of the sick dogs were characterized by a significant deficit in the circulating blood volume. Together with the indicators of the “consumption coagulopathy” stage of the DIC syndrome, the hemodynamic indexes indicate a moderate degree of shock stage II – the stable reversibility, but the magnitude of the circulating blood volume deficit determines the tendency towards shock irreversibility. Histological studies have established a significant proliferation of the stromal elements of the organ, the formation of specific complexes of vessels with sinuses, clogging with blood clots, and the organ's parenchyma dystrophy. Such changes characterize complete splenomegaly, which is based on the organo-pathology of the DIC syndrome. The deposition of “old” fibrin in the connective tissue structures of the spleen indicates that DIC syndrome continues throughout the entire period of hyperplastic changes in the organ. The presence of hyalinosis in blood vessel walls of the spleen parenchyma determines irreversible changes in them. Thus, DIC syndrome is the basis for splenomegaly development in dogs after acute spontaneous babesiosis. It is confirmed by laboratory blood tests and histologically by the presence of fibrin thrombi in the structures of the organ, which determine the organopathology of the syndrome. The information obtained serves to expand the concepts of the pathogenesis of blood protozoal disease, define the high risk of complications that can become fatal for the health and life of animals.

Kaposiform hemangioendothelioma/Kasabach–Merritt syndrome. Сlinical and laboratory characteristics. Analysis of clinical cases

Kaposiform hemangioendothelioma (KHE) is a rare, usually congenital vascular tumor. It resembles Kaposi sarcoma histologically, but etiologically it is not associated with herpes simplex virus type 8. KHE refers to tumors of intermediate malignancy degree. The most severe complication is the addition of thrombocytopenia and consumption coagulopathy, i.e. development of the Kasabach–Merritt syndrome/phenomenon (KMS), which determines the high mortality rate (up to 30%) in this histological variant. The frequency of occurrence of KMS is unknown. Over Patients with KHE/KMS have clear clinical and laboratory characteristics, which in most cases allow make to diagnose without histological confirmation. Over 7-year follow-up period 32 patients with KHE were registered in our center; in 90.6% of cases it was complicated by the development of KMS. The study was approved by the Independent Ethics Committee and Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. In the most of patients the tumor was detected from birth (84%), in half of the cases (52%) hematological complications were diagnosed simultaneously with the detection of the tumor. Сommon local complications include joint contractures, destruction of bone tissue, and invasion of neighboring organs. The half of the patients had changes in the heart function: from minor cardiac pathology to congenital defects. In addition, there were clinical and instrumental changes associated with volume overload: an increase in liver size, myocardial hypertrophy. Despite the presence of clear clinical and laboratory characteristics of KMS, some cases require differential diagnosis with other vascular anomalies accompanied by thrombocytopenia and consumption coagulopathy – with congenital hemangiomas (rapidly involuting congenital hemangioma), multifocal lymphangioendotheliomatosis with thrombocytopenia, kaposiform lymphangiomatosis, venous malformations. The parents of the patients agreed to use the information, including photos of children, in scientific research and publications.

Bleeding and Thrombosis: Insights into Pathophysiology of Bothrops Venom-Related Hemostasis Disorders

Toxins from Bothrops venoms targeting hemostasis are responsible for a broad range of clinical and biological syndromes including local and systemic bleeding, incoagulability, thrombotic microangiopathy and macrothrombosis. Beyond hemostais disorders, toxins are also involved in the pathogenesis of edema and in most complications such as hypovolemia, cardiovascular collapse, acute kidney injury, myonecrosis, compartmental syndrome and superinfection. These toxins can be classified as enzymatic proteins (snake venom metalloproteinases, snake venom serine proteases, phospholipases A2 and L-amino acid oxidases) and non-enzymatic proteins (desintegrins and C-type lectin proteins). Bleeding is due to a multifocal toxicity targeting vessels, platelets and coagulation factors. Vessel damage due to the degradation of basement membrane and the subsequent disruption of endothelial cell integrity under hydrostatic pressure and tangential shear stress is primarily responsible for bleeding. Hemorrhage is promoted by thrombocytopenia, platelet hypoaggregation, consumption coagulopathy and fibrin(ogen)olysis. Onset of thrombotic microangiopathy is probably due to the switch of endothelium to a prothrombotic phenotype with overexpression of tissue factor and other pro-aggregating biomarkers in association with activation of platelets and coagulation. Thrombosis involving large-caliber vessels in B. lanceolatus envenomation remains a unique entity, which exact pathophysiology remains poorly understood.

State of plasma hemostasis in newborn infants

Aim. To study the features of the plasma hemostasis in newborns with congenital IUI.Material and methods. The observation of 52 newborns with intrauterine infections was conducted. All the children were divided into two groups. The first group included 36 (69, 2%) patients with a severe IUI and the second - 16 (30,8) patients with a very slow course of the pathological process.Results and discussion. The results of the study showed that IUI in children has a generalized form of the course, with symptoms of microcirculatory dysfunction of the internal organs and systems.Conclusion. The study of the plasma component of hemostasis showed multidirectional changes in it in the form of activation of plasma clotting factors, at the same time there was an increase in the duration and time of blood clotting, indicating the development of consumption coagulopathy in this category of patients, whose severity depends on the course of fetal infections and tropism of the pathogen to the organs and tissues. Identified changes in the plasma component in children with intrauterine infections dictate the need for timely adequate corrective therapy.

Case Report: Treatment of a Severe Puff Adder Snakebite Without Antivenom Administration

Antivenoms are the treatment of choice for managing lethal snakebites. However, antivenoms may not be available in instances where non-native vipers are kept in captivity. We report a case of a puff adder (Bitis arietans) bite treated without antivenom. A 23-year-old man was bitten on his left hand by a puff adder that he illegally kept in his house. The swelling spread rapidly to the upper arm and there was a risk of bleeding, suggesting the need for antivenom administration, but this could not be acquired because of lack of stock. We initiated fluid resuscitation and administered recombinant thrombomodulin (rTM) to prevent venom-induced consumption coagulopathy. In addition, hyperbaric oxygen (HBO) treatment was also performed to reduce local swelling. The patient recovered without complications after the multidisciplinary treatment. Further studies are needed to prove the safety and efficacy of rTM administration and HBO therapy as an adjunct or alternative therapy with antiserum for fatal snakebite.

Repidly involuting congenital hemangioma

Congenital hemangiomas are rare benign vascular tumors that develop in utero and are fully formed by the time of birth. Depending on the ability to involution, there are three subtypes: RICH (repidly involuting congenital hemangioma), NICH (non involuting congenital hemangioma), PICH (partially involuting congenital hemangioma). PICH may be accompanied by thrombocytopenia and consumption coagulopathy. Despite clearly defined clinical and histological characteristics, it can be difficult to make a differential diagnosis between congenital hemangiomas and other vascular tumors (infantile hemangioma, kaposiform hemangioendothelioma/“fascicular” angioma and others). The clinical case in the article of a vascular tumor in a newborn complicated by thrombocytopenia and consumption coagulopathy was regarded as Kazabach-Merritt syndrome, which is based on kaposiform hemangioendothelioma/“fascicular” angioma. Rapid regression of the tumor and recovery of hemogram and coagulogram parameters, as well as anamnesis of the disease and initial characteristics of the tumor forced to reconsider the diagnosis. Based on the histological picture, the diagnosis of congenital hemangioma, RICH, was confirmed. Verification of the diagnosis made it possible to change therapeutic tactics and avoid chemotherapy. A giant hemangioma, accompanied by thrombocytopenia and consumption coagulopathy, may have a very favorable outcome – a complete resolution of the pathological process inherent in its natural course. The patient's parents agreed to use the information, including the child's photo, in scientific research and publications.