von Willebrand's disease in the dog and cat

Exploring the Regulatory Mechanism of Hedysarum Multijugum Maxim.-Chuanxiong Rhizoma Compound on HIF-VEGF Pathway and Cerebral Ischemia-Reperfusion Injury's Biological Network Based on Systematic Pharmacology

Background: Clinical research found that Hedysarum Multijugum Maxim.-Chuanxiong Rhizoma Compound (HCC) has definite curative effect on cerebral ischemic diseases, such as ischemic stroke and cerebral ischemia-reperfusion injury (CIR). However, its mechanism for treating cerebral ischemia is still not fully explained.

Methods: The traditional Chinese medicine related database were utilized to obtain the components of HCC. The Pharmmapper were used to predict HCC’s potential targets. The CIR genes were obtained from Genecards and OMIM and the protein-protein interaction (PPI) data of HCC’s targets and IS genes were obtained from String database. After that, the DAVID platform was applied for Gene Ontology (GO) enrichment analysis and pathway enrichment analysis. Finally, a series of animal experiments were carried out to further explore the mechanism of HCC intervention in CIR.

Results: The prediction results of systematic pharmacology showed that HCC can regulate CIR-related targets (such as AKT1, MAPK1, CASP3, EGFR), biological processes (such as angiogenesis, neuronal axonal injury, blood coagulation, calcium homeostasis) and signaling pathways (such as HIF-1, VEGF, Ras, FoxO signaling). The experiments showed that HCC can improve the neurological deficit score, decrease the volume of cerebral infarction and up-regulate the expression of HIF-1α/VEGF and VEGFR protein and mRNA (p < 0.05).

Conclusion: HCC may play a therapeutic role by regulating CIR-related targets, biological processes and signaling pathways found on this study.

Abnormal platelet activity in dogs and cats - impact and measurement

Abnormal platelet activity can either lead to bleeding tendencies or inappropriate thrombus formation and can occur secondarily to a wide variety of disease processes, with a range of clinical consequences and severity. This article will discuss the pathophysiology of platelet function abnormalities and consider a logical diagnostic approach applicable to veterinary practice. Recent advances in platelet function testing will then be discussed, with regards to detection of platelet dysfunction and tailoring of pharmacological manipulation. Although many of these tests are still confined to research or academic institutions, techniques for indirectly assessing platelet function are starting to become more widely available. Although we still require further research to develop guidelines for the use of these tests in clinical decision-making, the recent advances in this field are an exciting step forward in being able to detect and manage platelet dysfunction in both primary care and referral practice.

Inherited disorders of hemostasis in dogs and cats

Inherited disorders of hemostasis encompass abnormalities in primary hemostasis, coagulation, and fibrinolysis resulting from genetic mutations. There is significant variation in the phenotype expressed ranging from life limiting to the absence of overt clinical signs. Von Willebrand disease is the most common primary hemostatic disorder in dogs, and hemophilia A is the most common coagulation factor disorder. The diagnosis of inherited bleeding disorders is made by functional and/or quantitative evaluation. Genetic testing has added to the knowledge base, allowing prevention through targeted breeding. Avoidance of trauma and injury is paramount in the prevention of bleeding in animals diagnosed with inherited hemostatic disorders. Current therapeutic options include platelet transfusions, broad replacement of coagulation factors (e.g., plasma), targeted factor replacement (e.g., cryoprecipitate), antifibrinolytic agents and specific factor replacement, and treatment of the symptoms (i.e., bleeding) with blood transfusions.

Comparative aspects of blood coagulation

Blood coagulation is a basic physiological defense mechanism that occurs in all vertebrates to prevent blood loss following vascular injury. In all species the basic mechanism of clot formation is similar; when endothelium is damaged a complex sequence of enzymatic reactions occurs that is localized to the site of trauma and involves both activated cells and plasma proteins. The reaction sequence is initiated by the expression of tissue factor on the surface of activated cells and results in the generation of thrombin, the most important enzyme in blood clot formation. Thrombin converts soluble fibrinogen, via soluble fibrin monomers, into the insoluble fibrin that forms the matrix of a blood clot as well as exerting positive-feedback regulation that effectively promotes additional thrombin generation that facilitates the rapid development of a thrombus. Both spontaneous and trauma-induced haemorrhagic episodes can develop in all mammals with inherited or acquired abnormalities in one or more of the coagulant proteins. Experimental studies with plasma from a wide range of species have led to the conclusion that there are extensive differences in the rates of thrombin generation and fibrin formation among species. However, current evidence suggests that at least some of these quantitative differences are likely due to the use of non-species specific laboratory reagents. Although the individual proteins involved in the procoagulant pathways exhibit similar functions in all animals, differences in amino acid sequence cause incomplete homology and varying degrees of immunological cross-reactivity for the same protein across species.

Plasma von Willebrand factor-collagen binding activity in normal dogs and in dogs with von Willebrand's disease

A sensitive enzyme-linked immunosorbent assay was used for the simultaneous assessment of the amount of von Willebrand factor (vWF) in canine plasma and its ability to bind to canine collagen in vitro. In 60 normal dogs, there was close correlation between the concentration of vWF and its activity as determined by vWF-collagen binding. In 14 dogs with type I expressions of von Willebrand's disease, the ratio of vWF antigen to collagen binding activity was normal or only slightly increased. In 7 dogs with type II expressions of the disease, this ratio was consistently elevated suggesting a significant functional deficiency of the protein. Plasma from 3 dogs with type III von Willebrand's disease had little collagen binding activity because of the severe quantitative deficiency of the protein. The described assay permits the rapid assessment of both the quantity and quality of vWF in a dog. This information is necessary for the detection and characterization of canine von Willebrand's disease, particularly the type II expressions, which cannot be diagnosed by quantitative vWF assays alone.

Construction and characterization of an eightfold redundant dog genomic bacterial artificial chromosome library

A large insert canine genomic bacterial artificial chromosome (BAC) library was built from a Doberman pinscher. Approximately 166,000 clones were gridded on nine high-density hybridization filters. Insert analysis of randomly selected clones indicated a mean insert size of 155 kb and predicted 8.1 coverage of the canine genome. Two percent of the clones were nonrecombinant. Chromosomal fluorescence in situ hybridization studies of 60 BAC clones indicated no chimerism. The library was hybridized with dog PCR products representing eight genes (ADA, TNFA, GCA, MYB, HOXA, GUSB, THY1, and TOP1). The resulting positive clones were characterized and shown to be compatible with an eightfold redundant library.