Myocardial injury in dogs with snake envenomation and its relation to systemic inflammation

Cp40-mediated complement C3 inhibition dampens inflammasome activation and inflammatory mediators storm induced by Bitis arietans venom

The complement system plays a crucial role in various pathophysiological conditions, including snake envenomation. In this study, we investigated the effects of Bitis arietans venom on the complement system using an ex vivo human whole blood model. Our findings demonstrate that B. arietans venom was able to activate the complement system, leading to a significant increase in the production of anaphylatoxins (C3a/C3a-desArg, C5a/C5a-desArg) and the soluble Terminal Complement Complex (sTCC). Inhibition of the C3 component by Cp40, a C3-C3b inhibitor, resulted in the reduction of C3a/C3a-desArg, C5a/C5a-desArg, and sTCC levels to baseline in venom-stimulated samples. Furthermore, treatment with Cp40 promoted a substantial decrease in the production of pro-inflammatory mediators, such as Prostaglandin E2 (PGE2), IL-8/CXCL8, MCP-1/CCL2, and MIG/CXCL9. To further elucidate the molecular mechanisms, we utilized the THP-1 cell line differentiated into M0 macrophages. Incubation of these macrophages with human plasma, from the human whole blood treated with B. arietans venom, resulted in the expression of the NLRP3 inflammasome and the production of IL-8 and IL-1β. Importantly, Cp40 was able to diminish the production of these cytokines, as well as the levels of ASC and caspase-1 proteins. In conclusion, our results indicate that the inhibition of the complement by Cp40 at C3/C3b level can modulate the inflammatory response and inflammasome activation induced by B. arietans venom. These findings suggest that complement inhibition may be a promising therapeutic approach for managing the inflammatory complications associated with this snake envenomation.

Myocardial injury in dogs: a retrospective analysis on etiological, echocardiographic, electrocardiographic, therapeutic, and outcome findings in 102 cases

INTRODUCTION

In dogs, myocardial injury (MI) is a poorly characterized clinical entity; therefore, this study aimed to provide a detailed description of dogs affected by this condition.

ANIMALS, MATERIALS, AND METHODS

Dogs diagnosed with MI according to the concentration of cardiac troponin I (cTnI) were retrospectively searched. Signalment, diagnostic, therapeutic, and outcome data were retrieved. Dogs were divided into six echocardiographic (dilated cardiomyopathy phenotype; hypertrophic cardiomyopathy phenotype; hypertrophic cardiomyopathy phenotype with systolic dysfunction; abnormal echogenicity only; endocarditis; and no echocardiographic abnormalities suggestive of MI), four electrocardiographic (abnormalities of impulse formation; abnormalities of impulse conduction; abnormalities of ventricular repolarization; and no electrocardiographic abnormalities suggestive of MI), and nine etiological (infective; inflammatory; neoplastic; metabolic; toxic; nutritional; immune-mediated; traumatic/mechanical; and unknown) categories. Statistical analysis was performed to compare cTnI values among different categories and analyze survival.

RESULTS

One hundred two dogs were included. The median cTnI value was 3.71 ng/mL (0.2-180 ng/mL). Echocardiographic and electrocardiographic abnormalities were documented in 86 of 102 and 89 of 102 dogs, respectively. Among echocardiographic and electrocardiographic categories, the dilated cardiomyopathy phenotype (n = 52) and abnormalities of impulse formation (n = 67) were overrepresented, respectively. Among dogs in which a suspected etiological trigger was identified (68/102), the infective category was overrepresented (n = 20). Among dogs belonging to different echocardiographic, electrocardiographic, and etiological categories, cTnI did not differ significantly. The median survival time was 603 days; only eight of 102 dogs died due to MI.

CONCLUSIONS

Dogs with MI often have an identifiable suspected trigger, show various echocardiographic and electrocardiographic abnormalities, and frequently survive to MI-related complications.

Evaluation of plasma prealbumin as a novel inflammatory biomarker in dogs: a pilot study

Introduction

Prealbumin (PAB) is a plasma protein synthesized in the hepatic parenchymal cells. PAB has a short half-life (~2 days), and its concentration is affected by changes in transcapillary escape. Measurement of PAB is widely used in hospitalized patients in human medicine due to its decreasing concentration in states of inflammation and malnutrition. However, only a few studies are available in dogs. The aim of this study is to determine whether the plasma PAB concentration decreases in dogs with inflammation and to evaluate the relationship between the plasma PAB concentration and inflammation-related parameters in dogs.

Methods

A total of 94 dogs were divided into healthy (n = 33) and diseased (n = 61) groups. These were further divided into group A (n = 24) and group B (n = 37) according to plasma C-reactive protein (CRP) levels. Group A included dogs with a plasma CRP < 10 mg/L, and group B consisted of dogs with a plasma CRP ≥ 10 mg/L. Patient signalment, history, physical examination findings, hematologic and biochemical parameters, various inflammatory markers, and plasma PAB levels were investigated and compared between groups.

Results

The plasma PAB concentration was found to be lower in group B than in the other groups (p < 0.001), but no statistical difference was found when comparing the control group and group A (p > 0.05). A plasma PAB < 6.3 mg/dL predicted an increased CRP level (10 mg/L or greater) with a sensitivity of 89.5% and a specificity of 86.5%. Receiver operating characteristic curve analysis revealed that the area under the curve for PAB was higher than that for the white blood cell count, neutrophil count, albumin level, lactate level, neutrophil-to-lymphocyte ratio, and neutrophil percentage-to-albumin ratio. In addition, the PAB concentration was significantly negatively correlated with the CRP concentration (r = -0.670, p < 0.001).

Conclusion

In conclusion, this is the first study to demonstrate the clinical usefulness of the plasma PAB concentration as an inflammatory marker in dogs. These findings suggest that measuring the plasma PAB concentration along with the CRP concentration may be more useful for evaluating inflammation than measuring CRP alone in canine patients.

The Future of Biomarkers in Veterinary Medicine: Emerging Approaches and Associated Challenges

Simple Summary

In this review we seek to outline the role of new technologies in biomarker discovery, particularly within the veterinary field and with an emphasis on ‘omics’, as well as to examine why many biomarkers-despite much excitement-have not yet made it to clinical practice. Further we emphasise the critical need for close collaboration between clinicians, researchers and funding bodies and the need to set clear goals for biomarker requirements and realistic application in the clinical setting, ensuring that biomarker type, method of detection and clinical utility are compatible, and adequate funding, time and sample size are available for all phases of development.

Abstract

New biomarkers promise to transform veterinary practice through rapid diagnosis of diseases, effective monitoring of animal health and improved welfare and production efficiency. However, the road from biomarker discovery to translation is not always straightforward. This review focuses on molecular biomarkers under development in the veterinary field, introduces the emerging technological approaches transforming this space and the role of ‘omics platforms in novel biomarker discovery. The vast majority of veterinary biomarkers are at preliminary stages of development and not yet ready to be deployed into clinical translation. Hence, we examine the major challenges encountered in the process of biomarker development from discovery, through validation and translation to clinical practice, including the hurdles specific to veterinary practice and to each of the ‘omics platforms–transcriptomics, proteomics, lipidomics and metabolomics. Finally, recommendations are made for the planning and execution of biomarker studies with a view to assisting the success of novel biomarkers in reaching their full potential.

A Retrospective Evaluation of Snake Envenomation in Dogs in South Korea (2004-2021)

Snake envenomation is a medical emergency capable of causing local and systemic complications. However, information on venomous snakebite in dogs in South Korea is scarce. In this study, fifty-nine dogs treated at a private veterinary clinic from 2004 to 2021 were retrospectively studied. The aim was to characterize the demographics, elapsed time between snakebite and veterinary clinic presentation, laboratory findings, clinical signs, treatments, adverse reactions to antivenom, and prognosis of venomous snakebite. Snakebite was mostly observed between 12 p.m. and 5 p.m. from April to October. On the days of envenomation, the weather conditions were mostly cloudy, followed by rain/precipitation, and least frequently fair weather. Grassland was the most common incident location, and leashed dog walking was the most frequent activity when snakebite occurred. The main local symptoms were edema, hemorrhagic discharge, cutaneous erythema, ulceration, and necrosis. Major systemic clinical signs were tachypnea, tachycardia, altered mentation, ptyalism, and hypotension. Based on the time interval between snakebite and presentation at the veterinary clinic, two groups were defined: <4 h (Group 1, 49.2%) and ≥4 h (Group 2, 50.8%). Systemic inflammation was more frequently observed in Group 2. The level of C-reactive protein at presentation (p = 0.036) and the highest-level during hospitalization (p = 0.023) were significantly elevated in Group 2 (≥4 h). The dogs in Group 2 displayed more frequent muscle damage (increased creatine kinase) than the dogs in Group 1, and a higher level of creatine kinase was associated with delayed (≥4 h) presentation after snakebite (p = 0.003). All of the dogs were treated symptomatically, and 34 dogs (58%) received antivenom. Treatment with antivenom showed no adverse reactions in this study. All of the treated dogs recovered. One dog was euthanized without any treatment due to respiratory distress, hypotension, and cost constraints. In conclusion, this study provides baseline information on venomous snakebite in dogs in South Korea. The prognosis was excellent, especially when the dogs were treated within 4 h.

Profiling the Murine Acute Phase and Inflammatory Responses to African Snake Venom: An Approach to Inform Acute Snakebite Pathology

Snake envenoming causes rapid systemic and local effects that often result in fatal or long-term disability outcomes. It seems likely that acute phase and inflammatory responses contribute to these haemorrhagic, coagulopathic, neurotoxic, nephrotoxic and local tissue destructive pathologies. However, the contributory role of acute phase/inflammatory responses to envenoming is under-researched and poorly understood—particularly for envenoming by sub-Saharan African venomous snakes. To provide data to help guide future studies of human patients, and to explore the rationale for adjunct anti-inflammatory medication, here we used an in vivo murine model to systematically assess acute phase and inflammatory responses of mice to ten African snake venoms. In addition to investigating snake species-specific effects of venom on the cardiovascular system and other key organs and tissues, we examined the response to intravascular envenoming by acute phase reactants, including serum amyloid A, P-selectin and haptoglobin, and several cytokines. Venoms of the spitting (Naja nigricollis) and forest (N. melanoleuca) cobras resulted in higher acute phase and inflammatory responses than venoms from the other cobras, mambas and vipers tested. Naja nigricollis venom also stimulated a 100-fold increase in systemic interleukin 6. Thin blood films from venom-treated mice revealed species-specific changes in red blood cell morphology, indicative of membrane abnormalities and functional damage, lymphopenia and neutrophil leukocytosis. Our ex vivo assays with healthy human blood treated with these venoms identified that N. nigricollis venom induced marked levels of haemolysis and platelet aggregation. We conclude that African snake venoms stimulate very diverse responses in this mouse model of acute systemic envenoming, and that venoms of the African cobras N. nigricollis and N. melanoleuca, in particular, cause marked inflammatory and non-specific acute phase responses. We also report that several African snake venoms cause haemolytic changes. These findings emphasise the importance of understanding acute responses to envenoming, and that further research in this area may facilitate new diagnostic and treatment approaches, which in turn may lead to better clinical outcomes for snakebite patients.

Persistent hypercoagulability in dogs envenomated by the European adder (Vipera berus berus)

Background

Envenomation by the European adder, Vipera berus berus (Vbb), is a medical emergency. The overall in vivo haemostatic effects of pro- and anticoagulant components in Vbb venom, and the downstream effects of cellular injury and systemic inflammation, are unclear.

Objectives

To longitudinally describe the global coagulation status of dogs after Vbb envenomation and compare to healthy controls. A secondary aim was to investigate differences between dogs treated with and without antivenom.

Methods

Citrated plasma was collected at presentation, 12 hours (h), 24 h, 36 h and 15 days after bite from 28 dogs envenomated by Vbb, and from 28 healthy controls at a single timepoint. Thrombin generation (initiated with and without exogenous phospholipids and tissue factor), thrombin-antithrombin (TAT)-complexes and the procoagulant activity of phosphatidylserine (PS)-expressing extracellular vesicles (EVs), expressed as PS-equivalents, were measured.

Results

At presentation the envenomated dogs were hypercoagulable compared to controls, measured as increased thrombin generation, TAT-complexes and PS-equivalents. The hypercoagulability decreased gradually but compared to controls thrombin generation and PS-equivalents were still increased at day 15. The discrepancy in peak thrombin between envenomated dogs and controls was greater when the measurement was phospholipid-dependent, indicating that PS-positive EVs contribute to hypercoagulability. Lag time was shorter in non-antivenom treated dogs, compared to antivenom treated dogs <24 h after envenomation.

Conclusions

Hypercoagulability was measured in dogs up to 15 days after Vbb envenomation. Dogs treated with antivenom may be less hypercoagulable than their non-antivenom treated counterparts. Thrombin generation is a promising diagnostic and monitoring tool for Vbb envenomation.

Bitis arietans Snake Venom and Kn-Ba, a Snake Venom Serine Protease, Induce the Production of Inflammatory Mediators in THP-1 Macrophages

Bitis arietans is a snake of medical importance found throughout sub-Saharan Africa and in savannas and pastures of Morocco and western Arabia. The effects of its venom are characterized by local and systemic alterations, such as inflammation and cardiovascular and hemostatic disturbances, which can lead to victims' death or permanent disability. To better characterize the inflammatory process induced by this snake's venom, the participation of eicosanoids and PAF (platelet- activating factor) in this response were demonstrated in a previous study. In addition, edema and early increased vascular permeability followed by an accumulation of polymorphonuclear (PMN) cells in the peritoneal cavity were accompanied by the production of the eicosanoids LTB₄, LTC₄, TXB₂, and PGE₂, and local and systemic production of IL-6 and MCP-1. In this context, the present study focused on the identification of inflammatory mediators produced by human macrophages derived from THP-1 cells in response to Bitis arietans venom (BaV), and Kn-Ba, a serine protease purified from this venom. Here, we show that Kn-Ba, and even the less intensive BaV, induced the production of the cytokine TNF and the chemokines RANTES and IL-8. Only Kn-Ba was able to induce the production of IL-6, MCP-1, and IP-10, whereas PGE₂ was produced only in response to BaV. Finally, the release of IL-1β in culture supernatants suggests the activation of the inflammasomes by the venom of Bitis arietans and by Kn-Ba, which will be investigated in more detail in future studies.

Serial serum creatinine, SDMA and urinary acute kidney injury biomarker measurements in dogs envenomated by the European adder (Vipera berus)

Background

Acute kidney injury (AKI) is associated with high morbidity and mortality in dogs, but diagnosis may be impaired due the insensitivity of routine renal function biomarkers to detect earlier or milder forms of injury. Snake envenomation is one of several causes of AKI in dogs and humans. Dogs are commonly envenomated by the European adder (Vipera berus) between April and October each year, but few studies exist examining serial serum creatinine (sCr) and symmetric dimethylarginine (SDMA) measurements and AKI biomarkers in these dogs. Novel urinary biomarkers could improve clinical outcome by allowing earlier diagnosis of and intervention in AKI. The aim of this study was to assess the presence of AKI in dogs envenomated by V. berus at 12, 24 and 36 h after bite, as well as 14 days later, using sCr, SDMA and a panel of urinary AKI biomarkers normalised to urine creatinine (uCr), compared to a group of healthy control dogs.

Results

Thirty-five envenomated dogs and 35 control dogs were included. Serum creatinine did not exceed the upper reference limit at any time point in any dog after envenomation. Serum SDMA did not exceed 0.89 μmol/L in any dog. Compared to controls, urinary albumin/uCr, neutrophil gelatinase-associated lipocalin/uCr and monocyte chemotactic protein-1/uCr were significantly elevated 12 h (P <  0.0001, P <  0.0001, P = 0.01), 24 h (P <  0.001, P <  0.001, P = 0.002) and 36 h (P <  0.001, P <  0.001, P = 0.0008) after bite. Osteopontin/uCr was higher 24 and 36 h after bite (P < 0.0001), kidney injury molecule-1/uCr, interleukin-8/uCr and γ- glutamyl transferase/uCr were significantly higher 36 h after bite (P = 0.003, P = 0.0005, P = 0.001). Urinary cystatin C/uCr was not significantly different to controls at any timepoint. Biomarker/uCr ratios were not significantly different 14 days after envenomation compared to controls.

Conclusion

Urinary biomarker/Cr ratios are indicative of mild transient, non-azotaemic AKI in dogs envenomated by V. berus.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02851-8.

Bitis arietans Snake Venom Induces an Inflammatory Response Which Is Partially Dependent on Lipid Mediators

Bitis arietans is a snake of medical importance, as it is responsible for more accidents in humans and domestic animals than all other African snakes put together. The accidents are characterized by local and systemic alterations, such as inflammation, cardiovascular and hemostatic disturbances, which can lead victims to death or permanent disability. However, little is known about the envenomation mechanism, especially regarding the inflammatory response, which is related to severe clinical conditions triggered by the venom. Therefore, the aim of the present study was to evaluate the inflammatory response related to the B. arietans envenomation using a peritonitis mice model. By pharmacological interventions and use of mice genetically deficient of the 5-lipoxygenase enzyme (5-LO^-/-) or platelet-activating factor (PAF) receptor (PAFR^-/- the participation of eicosanoids and PAF in this response was also investigated. The obtained results demonstrated that the venom induces an in vivo inflammatory response, characterized by an early increased vascular permeability, followed by an accumulation of polymorphonuclear (PMN) cells in the peritoneal cavity, accompanied by the production of the eicosanoids LTB₄, LTC₄, TXB₂ and PGE₂, as well as the local and systemic production of IL-6 and MCP-1. These inflammatory events were attenuated by the pre-treatment with anti-inflammatory drugs that interfere in lipid mediators' functions. However, 5-LO^-/- mice did not show a reduction of inflammatory response induced by the venom, while PAFR^-/- mice showed a reduction in both the PMN leukocytes number and the local and systemic production of IL-6 and MCP-1. This study demonstrated that the Bitis arietans venom contains toxins that trigger an inflammatory process, which is partially dependent on lipid mediators, and may contribute to the envenomation pathology.

Ambulatory electrocardiography and serum cardiac troponin I measurement in 21 dogs envenomated by the European adder (Vipera berus)

BACKGROUND

Envenomation by the European adder (Vipera berus) is common in dogs in Europe. Cardiac arrhythmias occur but clinical studies of envenomated dogs are limited.

OBJECTIVES

To describe arrhythmias in dogs within 48 hours of envenomation, and investigate associations between arrhythmia grade, serum troponin I (cTnI), and snakebite severity score (SS score).

ANIMALS

Twenty-one client-owned dogs bitten by V berus.

METHODS

Prospective cohort study of envenomated dogs. Ambulatory electrocardiograms were recorded from presentation to 48 hours after snakebite, and arrhythmias graded 0 to 3 based on frequency and severity. Serum cTnI was measured at presentation, 12 hours, 24 hours, 36 hours, and 14 days after bite. An SS score of 1 to 3 was recorded at admission and based on clinical examination.

RESULTS

All dogs survived. Twelve dogs (57%) developed arrhythmias, all of which were ventricular in origin. Severe complex ventricular arrhythmias (VAs) were observed in 6 dogs (29%). Eighty-one percent of dogs (n = 17) had increased cTnI concentrations at 1 or more time points. Dogs that developed arrhythmias had significantly higher concentrations of cTnI at 12 hours (1.67 [0.04-32.68] versus 0.03 [0.01-0.052]; P = .002), 24 hours (1.88 [0.2-14.23] versus 0.06 [0.01-2.06]; P = .009), and 36 hours (3.7 [0.02-16.62] versus 0.06 [0.01-1.33]; P = .006) after bite compared to those that did not. Contingency table analysis showed that SS score was not significantly associated with arrhythmia grade (P = .9).

CONCLUSIONS AND CLINICAL IMPORTANCE

Myocardial cell injury, reflected by increased cTnI concentrations and VAs, is common after V berus envenomation in dogs. Prolonged electrocardiography monitoring is advised, particularly where cTnI is increased.

Cardiovascular biomarkers in dogs with systemic inflammatory response syndrome

OBJECTIVE

To measure plasma N-terminal fragments of pro-B-type natriuretic peptides (NT-proBNP) and cardiac troponin T (cTnT) concentration in hospitalized dogs and relate these markers to underlying conditions and evaluate their potential as prognostic markers in dogs with systemic inflammatory response syndrome (SIRS).

DESIGN

Prospective, observational, clinical study.

SETTING

Emergency department of a university teaching hospital.

ANIMALS

Sixty-nine dogs with SIRS examined in the emergency department were prospectively studied. Patient age ranged from 5 months to 15 years, and weight ranged from 5.5 to 75 kg.

MEASUREMENTS AND MAIN RESULTS

Blood samples were obtained at presentation, during hospitalization until discharge or death, and at a "control" visit (T1m) at least 1 month after hospital discharge. NT-proBNP was assayed with a commercially available canine ELISA, while cTnT was measured with an automated immunoassay previously used in dogs. A correlation procedure, mixed procedure on a linear model, and a logistic procedure were performed. Forty-four patients survived, 19 of which had control visits. cTnT concentrations were significantly higher than T0 and T1m at T12, T24, and T72. In 28 dogs, cTnT was detected during hospitalization, but cTnT was not detected in any dog at the control visits. Higher concentrations of cTnT were negatively associated with survival, irrespective of disease category. NT-proBNP concentrations were significantly higher than T0, T6, T12, and T1m at T24, T72, and T120, but were not associated with survival.

CONCLUSIONS

NT-proBNP and cTnT increased significantly in dogs with SIRS, regardless of the underlying disease process. Nonsurvivors displayed significantly higher cTnT concentrations during hospitalization.

Naja annulifera Snake: New insights into the venom components and pathogenesis of envenomation

Background

Naja annulifera is a medically important venomous snake occurring in some of the countries in Sub-Saharan Africa. Accidental bites result in severe coagulation disturbances, systemic inflammation and heart damage, as reported in dogs, and death, by respiratory arrest, in humans. Despite the medical importance of N. annulifera, little is known about its venom composition and the pathogenesis of envenomation. In this paper, the toxic, inflammatory and immunogenic properties of N. annulifera venom were analyzed.

Methodology/Principal findings

Venom proteomic analysis identified 79 different proteins, including Three Finger Toxins, Cysteine Rich Secretory Proteins, Metalloproteinases, Phospholipases A₂ (PLA₂), Hyaluronidase, L-amino-acid oxidase, Cobra Venom Factor and Serine Proteinase. The presence of PLA₂, hyaluronidase, fibrinogenolytic and anticoagulant activities was detected using functional assays. The venom was cytotoxic to human keratinocytes. In an experimental murine model of envenomation, it was found that the venom induced local changes, such as swelling, which was controlled by anti-inflammatory drugs. Moreover, the venom caused death, which was preceded by systemic inflammation and pulmonary hemorrhage. The venom was shown to be immunogenic, inducing a strong humoral immune response, with the production of antibodies able to recognize venom components with high molecular weight and to neutralize its lethal activity.

Conclusions/Significance

The results obtained in this study demonstrate that N. annulifera venom contains toxins able to induce local and systemic inflammation, which can contribute to lung damage and death. Moreover, the venom is immunogenic, an important feature that must be considered during the production of a therapeutic anti-N. annulifera antivenom.

N. annulifera is a dangerous snake that belongs to the Elapidae family. It is found in some of the countries in Sub-Saharan Africa and has caused accidents in humans and dogs. In this study, we characterized some of the biochemical, toxic and immunogenic properties of N. annulifera venom. We showed that the venom is composed of several proteins, some of which display enzymatic activities, such as phospholipase A2, hyaluronidase, metalloproteinases and serine proteinases. The venom promoted disturbances in the human coagulation system and was cytotoxic to human epidermal cells. Using a mouse model, we showed that the venom promotes local reactions that were reduced with anti-inflammatory drugs. The venom caused systemic inflammation, lung hemorrhage and death. Further, the venom stimulated production of high antibody titers when injected into mice and the antiserum produced was able to inhibit venom-induced death. This study demonstrated that N. annulifera venom contains toxins that trigger inflammatory process, which may contribute to the envenomation pathology. Moreover, the venom is immunogenic, an important aspect for the production of an efficient N. annulifera antivenom.

Prazosin protects myocardial cells against anoxia-reoxygenation injury via the extracellular signal‑regulated kinase signaling pathway

Ischemic heart disease (including coronary arterial atherosclerosis, or vascular cavity stenosis or occlusion) remains the leading cause of disease-associated mortality worldwide. Prazosin, a receptor blocker of postsynaptic adrenaline, is essential in expanding peripheral arteries, which decreases peripheral vascular resistance, and regulates anti-hypertensive action. However, the mechanisms underlying the effects of prazosin have not been fully elucidated. The aim of the present study was to investigate the protective effects of prazosin on myocardial cells against anoxia-reoxygenation injury in a mouse model. The regulatory effects of prazosin on blood lipid levels and blood pressure were investigated in experimental mice. Furthermore, inflammation responses and oxidative stress in myocardial cells were analyzed in mice treated with prazosin. Apoptotic myocardial cells were investigated in experimental mice treated with prazosin. In addition, apoptotic gene expression levels were evaluated in myocardial cells. Extracellular signal-regulated kinase (ERK) expression and phosphorylation was investigated in myocardial cells in mice with anoxia-reoxygenation injury following prazosin treatment. The activity and expression levels of nuclear factor of activated T cells (NF-AT), activator protein 1 (AP-1) and necrosis factor (NF)-κB were observed in myocardial cells. Furthermore, histological analyses were performed to investigate the benefits of prazosin treatment on anoxia-reoxygenation injury. The results of the present study identified that prazosin decreased the expression levels of inflammatory factors, interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-10 and IL-1 in the serum of mice exhibiting hypoxia/reoxygenation injury. Oxidative stress was observed to be improved and the apoptosis rate was decreased in myocardial cells in anoxia-reoxygenation injury model mice treated with prazosin. ERK expression and phosphorylation was upregulated, and expression levels of NF-AT, AP-1 and NF-κB were downregulated in the myocardial cells of mice treated with prazosin. Blood lipid levels and blood pressure of the anoxia-reoxygenation injury model mice were markedly improved following treatment with prazosin. Histological analysis indicated that the area, circumference fragmentation and segmentation of myocardial cells were significantly improved following prazosin treatment. Thus, these results indicate that prazosin treatment decreases inflammation responses, oxidative stress, and apoptosis of myocardial cells via regulation of the ERK signaling pathway. The findings indicate that prazosin may present as a potential therapeutic agent for the treatment of hypoxia/reoxygenation injury.

Twenty-four-hour ambulatory electrocardiography characterization of heart rhythm in Vipera berus-envenomed dogs

Background

Vipera berus has a worldwide distribution and causes high morbidity in dogs annually. A complication to envenomation may be cardiac arrhythmias. The purpose of this study was to investigate the prevalence, types, and timing of arrhythmias, using 24-h ambulatory electrocardiography (24-AECG), in dogs bitten by V. berus in the first 24–32 h after envenomation. In addition, this study aimed to investigate if there were differences in selected clinical and hematological- and biochemical variables (including cardiac troponin I) at admission between V. berus-envenomed dogs with and without detected pathologic arrhythmias. Seventeen prospectively recruited client-owned dogs acutely envenomed by V. berus, were therefore examined clinically and echocardiographically, sampled for blood, hospitalized, and monitored by 24-AECG.

Results

Clinically significant pathologic arrhythmias in this study were of ventricular origin, such as frequent single ventricular premature contractions (VPCs) and couplets of VPCs, episodes of ventricular tachycardia and idioventricular rhythm, and “R-on-T phenomenon”. Variations of these arrhythmias were detected by 24-AECG in eight (47%) of included dogs. No arrhythmias were detected by cardiac auscultation. Twenty-four hours following envenomation, four out of eight dogs experienced decreases (all P < 0.039), and three out of eight dogs experienced increases (all P < 0.034), in arrhythmic episodes. All four dogs bitten on a limb developed pathologic arrhythmias. Otherwise, no significant differences in clinical, hematological or biochemical variables were seen between dogs with pathologic arrhythmias and those without.

Conclusion

Forty-seven percent of dogs bitten by V. berus included in this study experienced pathologic arrhythmias of abnormal ventricular depolarization. During the first 24–32 h from the snakebite, some dogs experienced a decrease in arrhythmic episodes and others an increase in arrhythmic episodes. These findings indicate a potential value of repeated or prolonged electrocardiography monitoring of envenomed dogs for identification of which dogs that might benefit the most from prolonged hospitalization for optimal monitoring and treatment of cardiac abnormalities. In the present study, dogs that developed arrhythmias could not be differentiated from dogs that did not based on clinical findings or hematological or biochemical variables obtained at admission.

Plasma N-Terminal Probrain Natriuretic Peptide, Vascular Endothelial Growth Factor, and Cardiac Troponin I as Novel Biomarkers of Hypertensive Disease and Target Organ Damage in Cats

Background

In the absence of ocular target organ damage (ocular‐TOD), diagnosis of hypertension is challenging in cats. Biomarkers would provide additional support for the diagnosis of hypertension.

Hypothesis

Vascular endothelial growth factor (VEGF), N‐terminal probrain natriuretic peptide (NT‐proBNP), cardiac troponin I (cTnI), and urine protein‐to‐creatinine ratio (UPC) are predictors of systemic hypertension, will be increased in cats with hypertension with or without ocular‐TOD, and will decrease with antihypertensive treatment.

Methods

Plasma VEGF, NT‐proBNP, and cTnI concentrations and UPC were determined in healthy geriatric cats, normotensive cats with chronic kidney disease (CKD), hypertensive cats with evidence of hypertensive retinopathy (HT‐ocular‐TOD), and hypertensive cats without hypertensive ocular‐TOD (HT‐noTOD). Comparisons among groups were performed. Multivariable binary logistic regression models were built to identify independent biomarkers of hypertension and ocular‐TOD. Receiver operator characteristic (ROC) curves were drawn to assess clinical use.

Results

Cats with HT‐ocular‐TOD had significantly higher VEGF than all other groups (P < .05) and significantly higher NT‐proBNP than healthy cats (P < .001). Healthy cats had significantly lower cTnI than all other groups (P < .05). No differences were found among groups for UPC (P = .08). Cardiac troponin I and VEGF were independent predictors of hypertension (P < .05), but none of the biomarkers were independent predictors of ocular‐TOD. N‐terminal probrain natriuretic peptide concentrations decreased with antihypertensive treatment (P < .001). The ROC curves indicated that none of the biomarkers met the criteria to function as diagnostic tests for the diagnosis of hypertension or associated ocular‐TOD.

Conclusions and Clinical Significance

Despite statistical significance and changes with ocular‐TOD, antihypertensive treatment, or both, VEGF, NT‐proBNP, and cTnI did not function as useful diagnostic tests for hypertension. Persistently increased systolic blood pressure (SBP) measurements in combination with fundoscopy remains the preferred method for diagnosis of feline hypertension.

Biomarkers in Veterinary Medicine

This article summarizes the relevant definitions related to biomarkers; reviews the general processes related to biomarker discovery and ultimate acceptance and use; and finally summarizes and reviews, to the extent possible, examples of the types of biomarkers used in animal species within veterinary clinical practice and human and veterinary drug development. We highlight opportunities for collaboration and coordination of research within the veterinary community and leveraging of resources from human medicine to support biomarker discovery and validation efforts for veterinary medicine.

Cardiac Troponins in Dogs and Cats

Cardiac troponins are sensitive and specific markers of myocardial injury. The troponin concentration can be thought of as a quantitative measure of the degree of injury sustained by the heart, however, it provides no information on the cause of injury or the mechanism of troponin release. Conventionally, the cardiac troponins have been used for diagnosis of acute myocardial infarction in humans and have become the gold standard biomarkers for this indication. They have become increasingly recognized as an objective measure of cardiomyocyte status in both cardiac and noncardiac disease, supplying additional information to that provided by echocardiography and ECG. Injury to cardiomyocytes can occur through a variety of mechanisms with subsequent release of troponins. Independent of the underlying disease or the mechanism of troponin release, the presence of myocardial injury is associated with an increased risk of death. As increasingly sensitive assays are introduced, the frequent occurrence of myocardial injury is becoming apparent, and our understanding of its causes and importance is constantly evolving. Presently troponins are valuable for detecting a subgroup of patients with higher risk of death. Future research is needed to clarify whether troponins can serve as monitoring tools guiding treatment, whether administering more aggressive treatment to patients with evidence of myocardial injury is beneficial, and whether normalizing of troponin concentrations in patients presenting with evidence of myocardial injury is associated with reduced risk of death.

Serum cardiac troponin I concentrations in dogs with systemic inflammatory response syndrome

Background

Myocardial injury can be detected by cardiac troponin I (cTnI) concentration, which appears to be a predictor of short‐term death in critically ill patients. It is unknown if the best prognostic indicator of short‐term survival is cTnI measurement at admission or at later time points.

Hypothesis/Objectives

Measuring cTnI with a high‐sensitivity (HS) test at different time points after admission may be a better short‐term prognostic indicator than a single cTnI measurement at admission in dogs with systemic inflammatory response syndrome (SIRS).

Animals

Prospective, observational clinical study of 60 dogs with SIRS.

Methods

Cardiac troponin I concentration was measured in 133 serum samples, collected at days 1, 2, 3, and 5. Additionally, the acute patient physiologic and laboratory evaluation (APPLE) fast score was evaluated at admission. Prognostic capabilities of cTnI measurement and APPLE fast score for 28‐day mortality were assessed by receiver operating characteristic curve analysis.

Results

Forty‐one dogs with SIRS that survived 28 days had significantly lower serum cTnI concentrations at admission (median, 0.09 ng/mL; P = .004) and at the peak time point (median, 0.23 ng/mL; P = .01) compared to 19 nonsurvivors (median at admission, 0.63 ng/mL; median at peak, 1.22 ng/mL). Area under the curve to predict survival, using cTnI was similar at admission (0.732) and at peak (0.708), and was 0.754 for the APPLE fast score.

Conclusions and Clinical Importance

Increased cTnI concentration in dogs with SIRS is associated with poor outcome. Daily follow‐up measurement of cTnI concentration provides no additional prognostic information for short‐term mortality.

European Adder bites in dogs in southern Germany. A retrospective study over a 6.5-year period

OBJECTIVE

In some regions of Germany dogs are presented to the veterinarian due to a snake bite, especially during the summer. These patients often show multiple clinical and laboratory deviations. Without a significant history diagnosis is commonly difficult. Aim of this retrospective study was to analyze exposure, physical examination and clinical pathology results as well as course and outcome in dogs presented after European adder bites.

MATERIAL AND METHODS

Patient history of 15 dogs diagnosed with European adder bites over a 6.5-year-period were evaluated retrospectively. Normality of data distribution was tested by D'Agostino and Pearson omnibus normality test. Data were analyzed by T-test and Wilcoxon-matched-pairs-signed rank-test. P-values < 0.05 were considered significant.

RESULTS

All 15 dogs were presented within 1-48 hours after the snakebite. Most common clinical signs were local swelling and pain. Clinical pathology results on day 1 included haemoconcentration, leukocytosis and coagulopathy. On the second day of hospitalization heart rate and haematocrit declined significantly. Treatment included fluid therapy, antibiotic and antihistaminic drugs, glucocorticosteroids, antivenom and analgesics. One of 15 dogs died on the third day of hospitalization, all others were discharged. Duration of hospitalization was between 1 and 8 days (mean 4.2 ± 1.9 days).

CLINICAL RELEVANCE

Dogs affected by European adder bites most often present with swelling and pain at the site of the bite, most frequently on the head and limbs. Patients require intensive symptomatic therapy including antibiotics and analgesics, if indicated. With adequate therapy survival rate is high. For some patients European adder bites may be lethal.

The effect of a single dose of prednisolone in dogs envenomated by Vipera berus--a randomized, double-blind, placebo-controlled clinical trial

BACKGROUND

Treatment with glucocorticoids after snakebite in dogs is controversial and randomized clinical studies are missing. The objective of this study was to investigate the effect of a single dose of prednisolone in dogs envenomated by Vipera berus in a double-blind placebo-controlled study, after exclusion of dogs treated with antivenom. The two treatment groups were compared regarding clinical status and clinicopathological test results. A total of 75 dogs bitten by Vipera berus within the previous 24 hours were included. Clinical assessment, blood sampling and measurement of the bitten body part were done at admission (Day 1), after 24 hours (Day 2) and at a re-examination (Re-exam) after 10-28 days. Dogs were given prednisolone 1 mg/kg bodyweight (PRED) or saline (PLACEBO) subcutaneously in a randomized, double-blind clinical trial. Dogs were examined clinically and mental status and extent of edema were described. Furthermore, appetite, vomiting, diarrhea, cardiac arrhythmia and death were recorded. Concentrations of C-reactive protein (CRP) and high sensitivity cardiac Troponin I (cTnI), hematology variables and Prothrombin time (PT) were determined. Systemic inflammation was defined as present if CRP > 35 mg/l.

RESULTS

None of the dogs died during the study period. The mental status was reduced in 60/75 (80%) of dogs on Day 1, compared to 19/75 (25%) on Day 2. The proportion of dogs with no or only mild edema increased significantly from Day 1 to Day 2. About one-third of the dogs developed gastrointestinal signs during the study period. Cardiac arrhythmia was uncommon. Clinicopathological changes included increased total leucocyte count, CRP and troponin concentration on Day 2. The cTnI concentration was increased in dogs with systemic inflammation, compared to dogs without systemic inflammation. A single dose of prednisolone did not significantly affect any of the clinical or clinicopathological parameters studied, except for a higher monocyte count on Day 2 in dogs that had received prednisolone treatment.

CONCLUSION

The results of the present study do not support routine administration of a single dose of prednisolone 1 mg/kg subcutaneously in dogs bitten by Vipera berus.

The clinical value of whole blood point-of-care biomarkers in large animal emergency and critical care medicine

OBJECTIVE

To summarize the current medical literature and provide a clinical perspective of whole blood point-of-care (POC) biomarkers in large animal emergency and critical care practice.

DATA SOURCES

Original studies, reviews, and textbook chapters in the human and veterinary medical fields.

SUMMARY

POC biomarkers are tests used to monitor normal or disease processes at or near the patient. In both human and veterinary medicine these tools are playing an increasingly important role in the management of critical diseases. The most important whole blood POC biomarkers available for veterinary practitioners include l-lactate, cardiac troponin I, serum amyloid A, triglyceride, creatinine, and glucose, although many other tests are available or on the horizon.

CONCLUSION

Whole blood POC biomarkers enable clinicians to provide improved management of critical diseases in large animals. These tools are especially useful for establishing a diagnosis, guiding therapy, and estimating disease risk and prognosis.