Comparison of cytokine responses between dogs with sepsis and dogs with immune-mediated hemolytic anemia

KC-like chemokine as a biomarker of sepsis in dogs with pyometra

BACKGROUND

Sepsis, defined as a dysregulated inflammatory response to infection inducing organ dysfunction, is a common cause of mortality in both humans and animals. Early detection and treatment is essential for survival, but accurate diagnosis is challenging due to the lack of specific biomarkers for sepsis. This study explored the potential of the keratinocyte-derived chemokine (KC)-like protein in dogs as a biomarker of sepsis in dogs with bacterial uterine infection (pyometra). The aim was to compare KC-like concentrations in dogs with pyometra with or without sepsis and to assess associations between KC-like and clinical variables, including days of hospitalization as an outcome.

RESULTS

A mouse KC ELISA was validated and used to determine the concentrations of KC-like in serum from 34 dogs with pyometra and 18 healthy controls. Dogs with pyometra were classified as having sepsis based on two different criteria for systemic inflammatory response syndrome (SIRS), resulting in 74% and 30% sepsis-positive, respectively. The concentration of KC-like protein was higher in pyometra dogs with sepsis than in pyometra dogs without sepsis (p < 0.05) and in healthy controls (p < 0.0001) when using either of the two SIRS criteria. Moreover, KC-like was slightly increased in dogs with pyometra without sepsis compared with healthy controls when using the more stringent SIRS criteria (p < 0.05). Analyses of all dogs showed that KC-like concentrations correlated positively with hospitalization days, C-reactive protein (CRP) concentrations, white blood cells, and percentage of band neutrophils; however, KC-like correlated negatively with hemoglobin and did not correlate with circulating creatinine.

CONCLUSIONS

Our results suggest that circulating KC-like protein increases in dogs with sepsis in pyometra and that KC-like is associated with more severe clinical illness. These findings support a potential role of KC-like as a biomarker of sepsis; however, the true identity of KC-like in dogs has yet to be uncovered.

Evaluation of serum vitamin D metabolites, phagocytosis, and biomarkers of inflammation in dogs with naturally occurring diabetes mellitus

Naturally occurring diabetes mellitus (NODM) is one of the most common endocrine disorders in dogs and its etiology closely resembles type 1 diabetes mellitus (T1DM) in people. Human patients with T1DM commonly have cellular derangements consistent with inflammation, impaired immune function, and hypovitaminosis D. There is little information available regarding inflammatory biomarkers, immune function, and vitamin D status in diabetic dogs. Therefore, our objectives were to assess inflammatory biomarkers, vitamin D metabolites, and phagocytic capacity in diabetic dogs and determine whether associations exist with these variables and the level of clinical control or vitamin D metabolites. This was a prospective case-control study that included 20 otherwise healthy diabetic dogs (clinically controlled, n = 10; uncontrolled, n = 10) and 20 non-diabetic, healthy, age (± 2 years), breed, and sex matched controls. Complete blood count, biochemical panel, urinalysis, and fructosamine were performed at a single commercial reference laboratory. Basal plasma tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-8, and IL-10 were measured using a canine-specific multiplex bead-based assay. Serum C-reactive protein (CRP) was measured using a commercially available ELISA kit. Serum 25-hydroxyvitamin (OH)D3 and 24,25-dihydroxyvitamin (OH)2D3 were measured with HPLC. Phagocytosis of opsonized-Escherichia coli (E. coli) was evaluated with flow cytometry. Diabetic dogs had higher serum CRP concentrations than controls (p = 0.02). Plasma IL-8 concentrations were higher in diabetic dogs with uncontrolled clinical disease compared to controls (p = 0.02). Diabetic dogs had a lower percentage of leukocytes that phagocytized opsonized-E. coli (p = 0.02), but an increased number of bacteria phagocytized per cell (p < 0.001) compared to controls. No between-group differences were identified in vitamin D metabolites, nor were associations found between vitamin D and any variables. Fructosamine had a positive association with serum CRP concentration (rho = 0.35, p = 0.03) and number of bacteria phagocytized per cell (rho = 0.45, p = 0.004) in our cohort (n = 40). Like people with T1DM, diabetic dogs have a proinflammatory phenotype and phagocytic dysregulation that may be correlated with glycemic control.

Inflammatory biomarker concentrations in dogs with gastric dilatation volvulus with and without 24-h intravenous lidocaine

Background

Canine gastric dilatation volvulus (GDV) is characterized by tissue ischemia, reperfusion, and systemic inflammation. Evidence exists that lidocaine exerts anti-inflammatory properties and potentially improves outcome.

Design and setting

Prospective, randomized observational cohort study in client-owned dogs with GDV.

Objective

The primary objective of the study was the determination of pro- and anti-inflammatory biomarker concentrations in dogs with GDV with and without intravenous (IV) lidocaine therapy. The second objective was the evaluation of side effects of lidocaine.

Methods

Of 35 dogs included in the study, 20 dogs were assigned to receive lidocaine (LIDO) (2 mg/kg initially, followed by a continuous infusion at a rate of 50 μg/kg/min over 24 h) and 15 dogs not to receive lidocaine (NO-LIDO). Plasma concentrations of cytokines interleukin (IL)-6, IL-7, IL-8, IL-10, IL-15, IL-18, interferon gamma, keratinocyte chemotactic-like, monocyte chemotactic protein, and C-reactive protein (CRP) were measured at admission (prior any therapeutic intervention, T0), immediately after surgery (T1), at 24 h (T24), and at 48 h (T48) post-surgery.

Results

No significant differences in concentrations of any cytokines were found between the LIDO- and the NO-LIDO group. Significant lower CRP concentrations (median [range]) were found in dogs with lidocaine compared to dogs without at T24 (97.5 pg/mL [46.3-161.7] vs. 127.9 pg/mL [26.9-182.0]; p = 0.046) and T48 (73.7 pg/mL [18.4-169.4] vs. 116.3 pg/mL [71.4-176.8]; p = 0.002). Dogs receiving lidocaine exhibited significantly impaired mentation, a prolonged period of anorexia, and longer hospitalization compared to dogs without lidocaine.

Conclusion

Lidocaine administration had no impact on the plasma levels of cytokines during the 48-h study period, but significantly lower CRP concentrations were found at T24 and T48. Lidocaine's potential side effects require careful decision making regarding its use.

Biomarkers of endothelial activation and inflammation in dogs with organ dysfunction secondary to sepsis

Introduction

Alteration in endothelial function during sepsis is thought to play a key role in the progression of organ failure. We herein compared plasma concentrations of endothelial activation biomarkers vascular endothelial growth factor (VEGF), hyaluronan (HA), plasminogen activator inhibitor-1 (PAI-1) and von Willebrand factor (vWF), as well as inflammatory mediator concentrations (IL-6, IL-8, IL-10, C-reactive protein and monocyte chemoattractant protein-1) in dogs with sepsis to healthy dogs.

Methods

This study was a multicenter observational clinical trial conducted at two university teaching hospitals from February 2016 until July 2017. The study included 18 client-owned dogs hospitalized with sepsis and at least one distant organ dysfunction, as well as 20 healthy dogs. Plasma biomarker concentrations were measured using ELISA. Severity of illness in dogs with sepsis was calculated using the 5-variable acute physiologic and laboratory evaluation (APPLEFAST) score. Biomarker concentrations were compared between septic and healthy dogs using linear models.

Results

Septic peritonitis was the most frequent source of sepsis (11/18; 61%), followed by pneumonia (4/18; 22%). Ten dogs (56%) had only 1 organ dysfunction, whereas 3 dogs (17%) had 2, 3 (17%) had 3, 1 (6%) had 4 and 1 (6%) had 5 organ dysfunctions. The median APPLEFAST score in the septic dogs was 28.5 (Q1-Q3, 24-31). Mean plasma concentrations of all endothelial and inflammatory biomarkers, except vWF, were higher in the sepsis cohort than in controls. The mean endothelial biomarker concentrations in the septic cohort ranged from ~2.7-fold higher for HA (difference in means; 118.2 ng/mL, 95% credible limit; 44.5-221.7) to ~150-fold for VEGF (difference in means; 76.6 pg./mL, 95% credible limit; 33.0-143.4), compared to the healthy cohort. Fifteen dogs with sepsis (83%) died; 7 (46%) were euthanized and 8 (53%) died during hospitalization.

Conclusion

Dogs with naturally occurring sepsis and organ dysfunction had higher mean concentrations of biomarkers of endothelial activation and inflammation compared to healthy dogs, broadening our understanding of the pathophysiology of sepsis secondary to endothelial dysfunction.

The role of nutritional-immunological indices in estimating serum LPS and antioxidant enzyme activity and sepsis status in female dogs with pyometra caused by E. coli

The aim of this study was to diagnose pyometra and related sepsis status using cost-effective nutritional-immunological indices, antioxidants, and toxin levels in dogs and to investigate the utility of the indices in predicting toxin and antioxidant status. A total of 29 dogs were enrolled into the present study. Among these, 9 female dogs in their diestrus stages, were allocated for elective ovariohysterectomy. The pyometra group was also separated into two subgroups as Sepsis (+) and Sepsis (-). Blood samples were collected into two tubes containing EDTA for hematological analysis; without anticoagulant for serum progesterone, LPS concentration, and antioxidant levels at the time of diagnosis. Bacteriological and tissue samples of the uterus were collected after the ovariohysterectomy. Antioxidant activity, progesterone, and toxin concentration were determined by using commercial ELISA kits. Statistical analyses were performed using Stata version 16.1 and MedCalc 16 statistical software. Receiver operating characteristics curves were used for the threshold for evaluating pyometra and sepsis status. Pairwise comparisons were carried out of the area under the curve (AUC) for thresholds of nutritional immunologic indices (hemoglobin, albumin, lymphocyte, platelet (HALP) score; prognostic nutritional index (PNI); Albumin hemoglobin index (AHI)), serum LPS and antioxidant activity. Linear regression model was used for the estimation of serum LPS and antioxidant activity by using indices. Mean serum progesterone, LPS concentrations, and Nitric Oxide (NO) production were greater, while serum superoxide dismutase (SOD), tissue SOD, and glutathione peroxidase (GPx) activities were lower in dogs with pyometra. All nutritional-immunologic indices were lower in pyometra cases. Nutritional-immunologic indices (AUC of HALP:0.759; PNI:0.981; AHI 0.994), NO (AUC: 0.787) and SOD (AUC: 0.784) levels were useful for pyometra diagnosis. AHI and LPS were useful for the determination of sepsis status with the AUC values of 0.850 and 0.740, respectively. While AHI was useful for the estimation of serum LPS and NO concentration (p < 0.001), PNI was useful for serum SOD concentration (p = 0.003). In conclusion, PNI, HALP and AHI can be used in the diagnosis of pyometra, however, only AHI and LPS levels can be used in the diagnosis of sepsis. SOD and NO can be used to determine pyometra but have no effect on determining sepsis status. Additionally, the estimation of the levels of serum LPS, NO, and SOD activities can be done using the AHI and PNI values.

Cytokine Adsorption as an Adjunctive Treatment for Patients with Immune-Mediated Hemolytic Anemia Receiving Therapeutic Plasma Exchange: A Case Series of 3 Dogs

The use of cytokine adsorption is an emerging treatment for inflammatory diseases in human medicine. There are few reports of this treatment modality in veterinary medicine and no reports of the use of a cytokine adsorbent for immune-mediated hemolytic anemia (IMHA). These case reports illustrate the use of a cytokine adsorbent as an adjunctive treatment during therapeutic plasma exchange (TPE). All dogs were unresponsive to conventional treatment or were severely affected by rapid hemolysis of red blood cells. The aim was to treat all dogs with three sequential TPE sessions; however, one dog died before completion of three sessions and one dog required additional sessions. Preliminary evidence indicates that the use of a cytokine adsorption is well tolerated and can be considered as an adjunct in the management of IMHA that is severe or refractory to traditional treatment.

Evaluation of Host Constitutive and Ex Vivo Coccidioidal Antigen-Stimulated Immune Response in Dogs with Naturally Acquired Coccidioidomycosis

The early innate immune response to coccidioidomycosis has proven to be pivotal in directing the adaptive immune response and disease outcome in mice and humans but is unexplored in dogs. The objectives of this study were to evaluate the innate immune profile of dogs with coccidioidomycosis and determine if differences exist based on the extent of infection (i.e., pulmonary or disseminated). A total of 28 dogs with coccidioidomycosis (pulmonary, n = 16; disseminated, n = 12) and 10 seronegative healthy controls were enrolled. Immunologic testing was performed immediately, without ex vivo incubation (i.e., constitutive), and after coccidioidal antigen stimulation of whole blood cultures. Whole blood cultures were incubated with a phosphate-buffered solution (PBS) (negative control) or a coccidioidal antigen (rCTS1 (105-310); 10 µg/mL) for 24 h. A validated canine-specific multiplex bead-based assay was used to measure 12 cytokines in plasma and cell culture supernatant. Serum C-reactive protein (CRP) was measured with an ELISA assay. Leukocyte expression of toll-like receptors (TLRs)2 and TLR4 was measured using flow cytometry. Dogs with coccidioidomycosis had higher constitutive plasma keratinocyte chemotactic (KC)-like concentrations (p = 0.02) and serum CRP concentrations compared to controls (p < 0.001). Moreover, dogs with pulmonary coccidioidomycosis had higher serum CRP concentrations than those with dissemination (p = 0.001). Peripheral blood leukocytes from dogs with coccidioidomycosis produced higher concentrations of tumor necrosis factor (TNF)-α (p = 0.0003), interleukin (IL)-6 (p = 0.04), interferon (IFN)-γ (p = 0.03), monocyte chemoattractant protein (MCP)-1 (p = 0.02), IL-10 (p = 0.02), and lower IL-8 (p = 0.003) in supernatants following coccidioidal antigen stimulation when compared to those from control dogs. There was no detectable difference between dogs with pulmonary and disseminated disease. No differences in constitutive or stimulated leukocyte TLR2 and TLR4 expression were found. These results provide information about the constitutive and coccidioidal antigen-specific stimulated immune profile in dogs with naturally acquired coccidioidomycosis.

Increased thrombin activatable fibrinolysis inhibitor activity is associated with hypofibrinolysis in dogs with sepsis

Introduction

Disorders of coagulation are well-recognized in dogs with sepsis, but data regarding fibrinolysis disorders are limited. We aimed to characterize fibrinolysis in dogs with sepsis compared to healthy controls. We hypothesized that dogs with sepsis would be hypofibrinolytic, and that hypofibrinolysis would be associated with non-survival.

Methods

This was a prospective observational cohort study. We enrolled 20 client-owned dogs with sepsis admitted to the Cornell University Hospital for Animals and 20 healthy pet dogs. Coagulation and fibrinolytic pathway proteins including antiplasmin activity (AP), antithrombin activity (AT), thrombin activatable fibrinolysis inhibitor activity (TAFI), D-dimer concentration, fibrinogen concentration, and plasminogen activity were measured and compared between groups. Overall coagulation potential, overall fibrinolysis potential, and overall hemostatic potential were calculated from the curve of fibrin clot formation and lysis over time.

Results

Compared to healthy controls, dogs with sepsis had lower AT (P = 0.009), higher AP (P = 0.002), higher TAFI (P = 0.0385), and higher concentrations of fibrinogen (P < 0.0001) and D-dimer (P = 0.0001). Dogs with sepsis also had greater overall coagulation potential (P = 0.003), overall hemostatic potential (P = 0.0015), and lower overall fibrinolysis potential (P = 0.0004). The extent of fibrinolysis was significantly negatively correlated with TAFI. No significant differences were observed between survivors and non-survivors.

Discussion

Dogs with sepsis were hypercoagulable and hypofibrinolytic compared to healthy dogs, suggesting potential utility of thromboprophylaxis in this patient population. The association between high TAFI and low overall fibrinolysis potential might provide a potential mechanism for this hypofibrinolysis.

Carboxyhemoglobin as a diagnostic and prognostic biomarker of hemolytic anemias in dogs

BACKGROUND

Endogenous production of carbon monoxide during hemoglobin metabolism leads to the formation of carboxyhemoglobin. Carboxyhemoglobin concentration is abnormally high in humans with hemolytic anemia (HA).

HYPOTHESIS

Measurement of carboxyhemoglobin concentration can discriminate HA from other forms of anemia.

ANIMALS

Twenty-seven dogs with HA (immune-mediated HA, n = 22; microangiopathic HA, n = 5), 27 dogs with non-HA (kidney disease, n = 14; immune-mediated thrombocytopenia, [n = 6]; miscellaneous, n = 7) and 24 nonanemic control dogs.

METHODS

Prospective cohort study. Carboxyhemoglobin quantification, a CBC and biochemistry profile were performed upon admission, and survival to hospital discharge and at 30 days were the measured outcomes. Groups were compared by the Mann-Whitney and Kruskal-Wallis tests. Receiver-operator characteristic (ROC) analyses were used to examine the predictive utility of carboxyhemoglobin for the diagnosis of HA in anemic dogs.

RESULTS

Carboxyhemoglobin (median [interquartile range]) differed between dogs with HA (7.7% [2.5%]) and non-HA (3.6% [1.05]; P < .001) and dogs with HA and nonanemic dogs (3.5% [0.65%]; P < .001). No difference was detected between nonHA and nonanemic dogs. The area under the ROC curve for carboxyhemoglobin as predictor of HA in anemic dogs was 0.997 (95% CI, 0.99-1.00). Three optimal cut-off points were identified, including 5.05%, 4.55% and 4.85%, with corresponding sensitivity/specificity of 92.6%/100%, 100%/92.6% and 96.3%/96.3%, respectively. Neither carboxyhemoglobin nor any of the CBC or chemistry analytes were associated with survival.

CONCLUSIONS AND CLINICAL IMPORTANCE

Carboxyhemoglobin proved an excellent predictor of HA in dogs and might constitute a useful, ancillary tool for diagnosing and monitoring hemolytic anemias.

Allergy, inflammation, hepatopathy and coagulation biomarkers in dogs with suspected anaphylaxis due to insect envenomation

Objectives

To compare concentrations of biomarkers of; allergy [mast cell tryptase (MCT) and histamine], inflammation [interleukin (IL)-6,-10, and-18, CXCL8, CCL2, keratinocyte chemoattractant (KC), C-reactive protein (CRP)], endothelial glycocalyx shedding (hyaluronan), coagulation [prothrombin time, activated partial thromboplastin time, fibrinogen concentration, and von Willebrand Factor antigen, protein C (PC) and antithrombin (AT) activity], and hepatopathy [alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and total bilirubin] between dogs with anaphylaxis after suspected insect exposure, dogs with critical illness, and healthy dogs.

Design

This was a single center prospective clinical observational comparative biomarker study that included 25 dogs with anaphylaxis (evidence of insect exposure, acute dermatological signs, and other organ involvement), 30 dogs with other critical illness, and 20 healthy dogs. Differences across groups in biomarker concentrations were tested using one-way ANOVA or Kruskal-Wallis test, with significant P values (<0.05) reported for pairwise differences detected by post-hoc tests. Logistic regression models were used to calculate the area under the receiver operator characteristic curve (AUROC) for discrimination between anaphylaxis and non-anaphylactic illness.

Results

Histamine concentration was significantly higher in the anaphylaxis group than the healthy (P < 0.001) and critically ill groups (P < 0.001), whereas no differences in MCT were detected amongst groups. Biomarker concentrations that were increased relative to healthy dogs in both the anaphylaxis and critically ill groups included IL-10 (P < 0.001 and P = 0.007, respectively), CCL2 (P = 0.007 and P < 0.001, respectively) and AST (both P < 0.001), whereas only the critically ill group had significantly increased CRP (P < 0.001), IL-6 (P < 0.001), KC (P < 0.001), ALP (P < 0.001), and fibrinogen (P = 0.016) concentrations, compared to the healthy group. Only dogs with anaphylaxis had significantly higher hyaluronan (P = 0.021) and ALT (P = 0.021) concentrations, and lower PC (P = 0.030) and AT (P = 0.032) activities, compared to healthy dogs. Both CRP and histamine concentration showed good discrimination between anaphylaxis and other critical illness, with an AUROC of 0.96 (95% CI 0.91-1) and 0.81 (95% CI 0.69-0.93), respectively.

Conclusions

This preliminary study in dogs with anaphylaxis after suspected insect exposure, found evidence of an early innate immune response, glycocalyx shedding and anticoagulant consumption. Both CRP and histamine showed potential clinical utility for differentiation between anaphylaxis and other critical illness.

Identifying potential biomarkers and therapeutic targets for dogs with sepsis using metabolomics and lipidomics analyses

Sepsis is a diagnostic and therapeutic challenge and is associated with morbidity and a high risk of death. Metabolomic and lipidomic profiling in sepsis can identify alterations in metabolism and might provide useful insights into the dysregulated host response to infection, but investigations in dogs are limited. We aimed to use untargeted metabolomics and lipidomics to characterize metabolic pathways in dogs with sepsis to identify therapeutic targets and potential diagnostic and prognostic biomarkers. In this prospective observational cohort study, we examined the plasma metabolomes and lipidomes of 20 healthy control dogs and compared them with those of 21 client-owned dogs with sepsis. Patient data including signalment, physical exam findings, clinicopathologic data and clinical outcome were recorded. Metabolites were identified using an untargeted mass spectrometry approach and pathway analysis identified multiple enriched metabolic pathways including pyruvaldehyde degradation; ketone body metabolism; the glucose-alanine cycle; vitamin-K metabolism; arginine and betaine metabolism; the biosynthesis of various amino acid classes including the aromatic amino acids; branched chain amino acids; and metabolism of glutamine/glutamate and the glycerophospholipid phosphatidylethanolamine. Metabolites were identified with high discriminant abilities between groups which could serve as potential biomarkers of sepsis including 13,14-Dihydro-15-keto Prostaglandin A₂; 12(13)-DiHOME (12,13-dihydroxy-9Z-octadecenoic acid); and 9-HpODE (9-Hydroxyoctadecadienoic acid). Metabolites with higher abundance in samples from nonsurvivors than survivors included 3-(2-hydroxyethyl) indole, indoxyl sulfate and xanthurenic acid. Untargeted lipidomic profiling revealed multiple sphingomyelin species (SM(d34:0)+H; SM(d36:0)+H; SM(d34:0)+HCOO; and SM(d34:1D3)+HCOO); lysophosphatidylcholine molecules (LPC(18:2)+H) and lipophosphoserine molecules (LPS(20:4)+H) that were discriminating for dogs with sepsis. These biomarkers could aid in the diagnosis of dogs with sepsis, provide prognostic information, or act as potential therapeutic targets.

Serial analysis of blood biomarker concentrations in dogs with pneumonia, septic peritonitis, and pyometra

BACKGROUND

Prolonged antimicrobial drug (AMD) treatment is associated with antimicrobial resistance development. Biomarker measurement may aid treatment decision-making.

OBJECTIVES

Investigate temporal changes in blood biomarker concentrations in dogs undergoing treatment for pulmonary and intra-abdominal infections; compare time to biomarker concentration normalization with duration of clinician-directed AMD treatment.

ANIMALS

Forty-two client-owned dogs with pneumonia (n = 22), septic peritonitis (n = 10), or pyometra (n = 10).

METHODS

Plasma concentrations of C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin, procalcitonin, nucleosomes, cell-free DNA (cfDNA), high-mobility group box-1 (HMGB1), CC-motif chemokine ligand-2 (CCL2), CXC-motif chemokine ligand-8 (CXCL8), and keratinocyte chemoattractant-like (KC-Like) were quantitated in samples collected on days 1, 3, 7, 14, 28, and 60. Treatment was directed by clinicians blinded to biomarker concentrations.

RESULTS

Concentrations of CCL2, CRP, and KC-Like were maximal on D1, concentrations of SAA, cfDNA, HMGB1, and nucleosomes were maximal on D3 and haptoglobin concentrations were maximal on D7. These maximal concentrations were significantly different from those on D60. Concentrations of CRP and SAA decreased by 80% from peak and into respective reference intervals before AMDs were discontinued. For CRP, the median (interquartile range [IQR]) times to 20% peak and normal were 7 (6-9) and 7 (6-12) days, respectively, and for SAA they were 4 (4, 5) and 6 (5-8) days, respectively, compared to a median (IQR) duration of AMD prescribing of 16 (12-23) days (all P < .0001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Biomarker concentrations normalized within 7 to 14 days. Serial measurements of CRP and SAA might aid identification of disease resolution and could help guide AMD prescription decision-making.

Establishing a reference interval for acute phase proteins, cytokines, antioxidants and commonly measured biochemical and hematologic parameters in the northern fur seal (Callorhinus ursinus)

Over the past several decades there has been a precipitous decline of northern fur seals (Callorhinus ursinus; NFS) at their breeding grounds on the Pribilof Islands in the Bering Sea. The cause of this decline is likely multifactorial and could include changes in environmental parameters, prey abundance and distribution as well as exposure to pathogens and pollutants. Evaluation of inflammatory markers and antioxidant levels of the current population of fur seals in addition to hematologic and biochemical profiles could provide important information regarding health and subclinical or clinical disease in this population. Serum and plasma samples were obtained from clinically healthy adult female NFS and references intervals were determined for multiple parameters that can be altered in response to the presence of disease and environmental stressors. We established a reference interval for cytokines involved in acute inflammation and infection (TNFa, IL1, IL6, IL8, KC, IL10, C-reactive Protein) by utilizing commercially available canine cross-reactive antibodies. Reference intervals were also established for reactive oxygen species (hydrogen peroxide and malondialdehyde), as well as antioxidant levels (vitamin E and selenium) and acute phase proteins evaluated by serum electrophoresis. To improve the ability to compare and interpret indicators of health and disease in this species, we developed reference intervals for commonly utilized hematologic and biochemical tests in addition to the aforementioned markers of oxidative stress and inflammatory biomarkers. There were several animals identified as outliers indicating that they may have had subclinical illness or inflammation. Further investigation utilizing these tests in clinically ill animals and comparison to animals that exhibit normal behavior and no overt signs of illness could increase our understanding of the utility of measuring these parameters in this species.

Use of serum hyaluronic acid as a biomarker of endothelial glycocalyx degradation in dogs with septic peritonitis

OBJECTIVE

To describe daily changes in serum concentrations of hyaluronic acid (HA), a biomarker of endothelial glycocalyx degradation, in dogs with septic peritonitis and to determine whether relationships exist among serum concentrations of HA and biomarkers of inflammation and patient fluid status.

ANIMALS

8 client-owned dogs.

PROCEDURES

Serum samples that had been collected for a previous study and stored at -80°C were used. Blood samples were collected at admission and daily thereafter during hospitalization and were analyzed for concentrations of HA and interleukins 6, 8, and 10. Patient data including acute patient physiologic and laboratory evaluation score, type and amount of fluids administered daily, and daily CBC and lactate concentration results were recorded. To determine the significant predictors of HA concentration, a general linear mixed model for repeated measures was developed.

RESULTS

All dogs survived to discharge. Concentrations of HA ranged from 18 to 1,050 ng/mL (interquartile [25th to 75th percentile] range, 49 to 119 ng/mL) throughout hospitalization. Interleukin-6 concentration was a significant predictor of HA concentration as was total administered daily fluid volume when accounting for interleukin-6 concentration. When fluid volume was analyzed independent of inflammatory status, fluid volume was not a significant predictor. Concentrations of HA did not significantly change over time but tended to increase on day 2 or 3 of hospitalization.

CONCLUSIONS AND CLINICAL RELEVANCE

Results supported the theory that inflammation is associated with endothelial glycocalyx degradation. Dogs recovering from septic peritonitis may become more susceptible to further endothelial glycocalyx damage as increasing fluid volumes are administered.

Kinetics of Plasma Cytokines, Angiopoietin-2, and C-Reactive Protein in Dogs With Gastric Dilatation Volvulus

Background: The degree of systemic inflammation, reperfusion injury and endothelial activation are potentially important determinants of clinical outcomes in dogs with gastric dilatation volvulus (GDV).

Objective: To evaluate plasma concentrations and kinetics of inflammatory markers in dogs with GDV over a time frame of 48 h, and to compare to healthy dogs.

Design and Setting: Prospective, observational cohort study in client-owned dogs with GDV.

Materials and Methods: Fifteen dogs with GDV and 9 healthy control dogs were enrolled. Plasma concentrations of interleukin (IL)-6, IL-7, IL-8, IL-10, IL-15, IL-18, interferon gamma (IFN-γ), keratinocyte chemotactic-like, monocyte chemotactic protein (MCP)-1, Angiopoietin (Ang)-2, and C-reactive protein (CRP) were measured at admission (prior any therapeutic intervention, (T0), immediately after surgery (T1), 24 ± 4 h (T24), and 48 ± 4 h (T48) post-surgery. Cytokines were measured using multiplex magnetic bead assay. Plasma Ang-2 was measured with a commercial human ELISA test kit validated for dogs.

Results: Dogs with GDV had significantly higher plasma concentrations of IFN-γ and IL-10 compared to healthy control dogs at all time points. Concentrations of IL-6 were significantly higher at T1 and T24, concentrations of MCP-1 at T24, and concentrations of CRP at T24 and T48. A significant increase between T0 and T1 was found for IL-6, IL-10, and CRP, between T1 and T24 for IL-8, IFN-γ, MCP-1, and CRP, and between T24 and T48 for IL-15, Ang-2, and CRP. A significant decrease between T0 and T1 was found for IL-7, IL-8, IL-15, IL-18, and Ang-2; between T1 and T24 for IL-6 and KC-like; and between T24 and T48 for IL-6.

Conclusion: In GDV dogs, a mild pro-inflammatory reaction was present at admission, which peaked immediately after and up to 24 h post-surgery, mainly represented by IL-6, IFN-γ, MCP-1, and CRP, and which decreased at T48. In addition, the anti-inflammatory IL-10 was increased in GDV dogs at all time points.

RNA sequencing of whole blood in dogs with primary immune-mediated hemolytic anemia (IMHA) reveals novel insights into disease pathogenesis

Immune-mediated hemolytic anemia (IMHA) is a life-threatening autoimmune disorder characterized by a self-mediated attack on circulating red blood cells. The disease occurs naturally in both dogs and humans, but is significantly more prevalent in dogs. Because of its shared features across species, dogs offer a naturally occurring model for studying IMHA in people. In this study, we used RNA sequencing of whole blood from treatment-naïve dogs to study transcriptome-wide changes in gene expression in newly diagnosed animals compared to healthy controls. We found many overexpressed genes in pathways related to neutrophil function, coagulation, and hematopoiesis. In particular, the most highly overexpressed gene in cases was a phospholipase scramblase, which mediates the externalization of phosphatidylserine from the inner to the outer leaflet of cell membranes. This family of genes has been shown to be critically important for programmed cell death of erythrocytes as well as the initiation of the clotting cascade. Unexpectedly, we found marked underexpression of many genes related to lymphocyte function. We also identified groups of genes that are highly associated with the inflammatory response and red blood cell regeneration in affected dogs. We did not find any genes that distinguished dogs that lived vs. those that died at 30 days following diagnosis, nor did we find any relevant genomic signatures of microbial organisms in the blood of affected animals. Future studies are warranted to validate these findings and assess their implication in developing novel therapeutic approaches for dogs and humans with IMHA.

Evaluation of cytokine concentrations in a trehalose-stabilised lyophilised canine platelet product: a preliminary study

Background

Platelet transfusion is indicated for haemorrhage due to severe thrombocytopenia and for trauma associated coagulopathy. Febrile non-haemolytic transfusion reactions are a common complication of platelet transfusions in people and may be due to accumulated inflammatory cytokines. The present study aimed to determine the cytokine profile of a novel canine lyophilised platelet product following reconstitution, to assess the lyophilised platelets’ activation response to physiological platelet agonists and to compare the cytokine profiles of basal and stimulated canine lyophilised platelets.

Methods

Cell counts and biochemical analyses were conducted following reconstitution. Cytokine concentrations were measured with a canine-specific multiplex immunocapture assay and with an electrochemiluminescent ELISA. Aliquots of reconstituted product from three separate vials were activated for 10 minutes under non-stirred conditions using adenosine diphosphate, thrombin or convulxin and their cytokine concentrations compared with unactivated samples. Flow cytometry and light-transmission aggregometry were used to evaluate the product’s ability to express a procoagulant surface, degranulate and aggregate. Fresh platelet-rich plasma was used as a positive control.

Results

The product had a mean±SD particle count of 1.23±0.2×10⁹/ml, contained platelets that expressed surface phosphatidylserine before agonist stimulation and was capable of aggregation in response to thrombin stimulation suggesting that the product may have haemostatic potential following in vivo administration. Cytokine concentrations measured by the immunocapture assay were generally low, while twofold to threefold increases relative to published intervals were noted for several cytokines using the ELISA. Concentrations of chemokine (C-X-C) motif ligand 8 and tumour necrosis factor-α were significantly increased as measured by the ELISA, but not by the immunocapture assay, while concentrations of KC-like were significantly increased as measured by the immunocapture assay. Stimulation with platelet agonists did not affect measured cytokine concentrations.

Conclusion

Further study of the effects of administration of this lyophilised platelet product is warranted.

Comparative study of the use of miltefosine, miltefosine plus allopurinol, and allopurinol in dogs with visceral leishmaniasis

Visceral leishmaniasis (VL) is an infectious disease caused by the protozoan parasite Leishmania (Leishmania) infantum, an intracytoplasmic parasite that affects humans and other species of domestic and wild mammals. In Brazil, the treatment of canine visceral leishmaniasis (CVL) with miltefosine has been implemented since 2016, and the reports on the clinical and immunological conditions of treated dogs are scarce. Thus, this study aimed to assess and monitor the clinical, laboratory, and immunological condition of dogs with CVL before (D₀) and after (D₂₉) using three pharmacotherapeutic protocols: miltefosine monotherapy (Milteforan™, Virbac) (G1), miltefosine plus allopurinol (G2), and allopurinol monotherapy (G3). Forty-five dogs with CVL were assigned to one of three treatment groups. The dogs were evaluated for clinical signs, was well as haematological, biochemical, serological, and cytokine levels. Significant reduction in clinical scores was observed in all protocols, with no differences between groups. We did not observe a clinical cure in any of the dogs in the groups. Haematological and biochemical parameters showed slow recovery, with better results observed in G2. Anti-Leishmania antibody titre remained increased in all groups. The quantification of serum cytokines demonstrated a mixed Th1/Th2 profile in CVL. The IL-2 levels decreased in all groups after treatment. Evaluation of IFN-y and IL-10 did not show changes in the groups analysed, and it did not contribute to short term therapeutic monitoring. All therapeutic protocols promoted, to varying degrees, an improvement in the general condition (clinical signs, haematological, and biochemical levels) of the animals. Through clinical-pathological exams, we found that the combination of miltefosine plus allopurinol promoted better effects in the short-term, representing the best choice for the treatment of CVL, even when compared to the only therapeutic protocol allowed in Brazil, miltefosine monotherapy. Through the quantification of cytokines, IL-2 proved to be a potential therapeutic marker for the monitoring and follow-up of dogs with CVL.

Cytokine and Chemokine Profiling in Cats With Sepsis and Septic Shock

Background: Sepsis is a life-threatening condition associated with an exacerbated production of both pro- and anti-inflammatory cytokines that can promote a hyperactive response to infection or induce immunoparalysis. Data regarding the immune response to sepsis in cats are scarce. Establishing the profiles of cytokines and chemokines in feline sepsis to characterize the nature of the immune responses to sepsis might enable individualized treatments to be developed and targeted.

Objective: To evaluate the cytokine and chemokine network in cats with sepsis and septic shock, and to investigate the associations of these analytes with disease severity and outcome.

Methods: Blood samples prospectively collected at presentation of cats with sepsis and septic shock to two veterinary teaching hospitals were analyzed. Forty healthy cats were included as controls. A 19-plex feline cytokine/chemokine magnetic bead assay system was used to measure analytes in citrated plasma samples. Cytokine concentrations were compared between groups using the Kruskal-Wallis test with Dunn's post-hoc correction for multiple comparisons. Cytokine concentrations were compared between survivors and non-survivors with the Mann-Whitney U test. Odds ratios were calculated using logistic regression. A multivariable logistic regression model for prediction of septic shock was constructed.

Results: The study enrolled 35 septic cats. Many cytokines were undetectable in both sick and healthy control cats and were excluded from subsequent analyses. Comparisons of cytokine concentrations among healthy controls, cats with sepsis (n = 12) and cats with septic shock (n = 23) revealed that sick cats (sepsis or septic shock) had significantly higher plasma concentrations of IL-6, IL-8, KC-like, and RANTES compared to healthy controls. The combination of MCP-1, Flt-3L, and IL-12 was predictive of septic shock. None of the cytokines analyzed was predictive of outcome in this study population.

Conclusion: Plasma concentrations of IL-6, IL-8, KC-like, and RANTES are increased in cats with sepsis and may play important roles in pathogenesis. Multivariable modeling suggested that analysis of cytokines might aid differentiation of septic shock from sepsis. None of the cytokines analyzed was predictive of outcome. Measurement of these cytokines might enable future studies to better diagnose and characterize feline sepsis and septic shock.

Evaluation of the host cytokine response in dogs with sepsis and noninfectious systemic inflammatory response syndrome

OBJECTIVE

To quantify plasma cytokine concentrations in dogs with sepsis and noninfectious systemic inflammation and to evaluate the association between plasma cytokines and outcome in dogs with sepsis.

DESIGN

Prospective, observational cohort study.

SETTING

University teaching hospital.

ANIMALS

Forty-five dogs with sepsis, 10 dogs with noninfectious systemic inflammation (nSIRS), and 15 healthy controls were consecutively enrolled from June 2015 to February 2016 and followed to hospital discharge. Dogs with sepsis satisfied ≥2 SIRS criteria and had a documented or highly suspected bacterial infection. Dogs with nSIRS satisfied ≥2 SIRS criteria but had no evidence of infection. Dogs <3 kg and those with documented coagulopathy were excluded.

INTERVENTIONS

Measurement of inflammatory cytokines and high-mobility group box-1 (HMGB-1) was performed on each group.

MEASUREMENTS AND MAIN RESULTS

High-mobility group box-1 concentrations were analyzed by ELISA. Plasma concentrations of 13 cytokines were measured in singlet using multiplex magnetic bead assays. Kruskal-Wallis with Dunn's multiple comparison tests were used to compare biomarker concentrations between groups. Mann-Whitney U-tests were used to compare biomarker concentrations between survivors and nonsurvivors. Associations between biomarkers were evaluated using Spearman's correlation coefficients. Independent outcome predictors were identified using multivariable logistic regression. Alpha was set at 0.05. Concentrations of interleukin (IL)-6, C-X-C motif chemokine (CXCL)-8, keratinocyte-derived chemokine (KC)-like, C-C motif chemokine ligand 2 (CCL2), and HMGB-1 were significantly greater in dogs with sepsis versus healthy controls (all P ≤ 0.034). In dogs with sepsis, only CCL2 was independently associated with survival (odds ratio [OR] 0.996, 95% CI 0.993-0.999, P = 0.004). A cut-off of 385 pg/mL for CCL2 was 80% sensitive and 91.4% specific for nonsurvival (area under the ROC curve [AUROC] 0.866).

CONCLUSIONS

Dogs with sepsis have significantly increased concentrations of HMGB-1 and inflammatory cytokines, including IL-6, CXCL8, and KC-like. Increased CCL2 concentration is a negative prognostic indicator in dogs with sepsis. These findings should be confirmed using duplicate analyses in larger, distinct populations of dogs with sepsis before applying them to clinical patients.

High Mobility Group Box-1 and Pro-inflammatory Cytokines Are Increased in Dogs After Trauma but Do Not Predict Survival

Trauma is common in dogs and causes significant morbidity and mortality, but it remains challenging to predict the prognosis of dogs with traumatic injuries. This study aimed to quantify plasma high-mobility group box-1 (HMGB-1) and cytokine concentrations in dogs with moderate-to-severe trauma, and to evaluate the association between these biomarkers and the injury severity and survival to discharge. Using a prospective, observational case-control study design, 49 dogs with an animal trauma triage (ATT) score ≥3 were consecutively enrolled from 07/2015 to 10/2017 and followed to hospital discharge. Dogs <3 kg and those with pre-existing coagulopathies were excluded. Thirty three healthy control dogs were also enrolled. Illness and injury severity scores including the acute patient physiologic and laboratory evaluation (APPLE) were calculated using at-presentation data. Plasma HMGB-1 concentrations were measured by ELISA; concentrations of 13 cytokines were measured using multiplex bead-based assays and separately concentrations of 4 cytokines were measured using a multiplex canine-specific ELISA. All biomarkers were measured in duplicate. Mann-Whitney U tests were used to compare biomarker concentrations between groups and between survivors and non-survivors. Associations between biomarkers were evaluated using Spearman's correlation coefficients. Independent predictors of survival were identified using multivariable logistic regression. Alpha was set at 0.05. Plasma concentrations of HMGB-1, interleukin-6, C-X-C motif chemokine-8, keratinocyte chemoattractant-like, and C-C chemokine ligand-2 were significantly greater in injured dogs vs. controls (all P ≤ 0.011). In univariate analyses, HMGB-1 was significantly greater in non-survivors 46.67 ng/mL (8.94-84.73) compared to survivors 6.03 ng/mL (3.30-15.75), (P = 0.003). Neither HMGB-1 or the cytokines were associated with survival independent of illness severity as measured by the APPLE score, however.

Neutrophil Extracellular Traps in Plasma from Dogs with Immune-mediated Hemolytic Anemia

Background

Neutrophil extracellular traps (NETs) are part of the innate immune response and are essential in local pathogen control, but are associated with pathological inflammation, organ damage, autoimmunity, and thrombosis. Immune‐mediated hemolytic anemia (IMHA) is a pro‐inflammatory, prothrombotic disease associated with high mortality.

Hypothesis/Objectives

Neutrophil extracellular traps (NETs) are a feature of the inflammatory process in dogs with IMHA. The objective of the study was to evaluate plasma from dogs with IMHA for the presence of 2 indirect markers and 1 direct marker of NETs.

Animals

Healthy client‐owned dogs (56) and hospitalized dogs with IMHA (n = 35).

Methods

Prospective study. Plasma samples for all dogs were evaluated for cell‐free DNA using a fluorescence assay, histone‐DNA (hisDNA) complex using an ELISA, and citrullinated histone H3 (specific for NETosis) using Western blot. Reference intervals were generated using plasma from healthy dogs.

Results

In dogs with IMHA, cell‐free DNA concentration was above the reference interval in 17% of samples with a median (range) of 1.0 μg/mL (0.1–17.3), and hisDNA concentration was above the reference interval in 94% of samples with a median (range) of 30.7 × pooled normal plasma (PNP; 0.6–372.1). Western blot for citrullinated histone H3 identified detectable bands in 84% samples from dogs with IMHA.

Conclusions and Clinical Importance

The assay for cell‐free DNA detected evidence of NETs in fewer dogs than did the other approaches. Excessive NETs appears to be a feature of IMHA in dogs and contributions to the prothrombotic state deserve further study.

Immune Function in Critically Ill Dogs

Background

People with critical illness (CI) commonly develop various forms of immune dysfunction, however, there is limited information concerning immune dysfunction in dogs with CI.

Hypothesis

The immune response in CI dogs differs from that of healthy dogs.

Animals

Immunologic variables were compared between 14 dogs with CI, defined as APPLE_fast score of >20 points, admitted to the University of Missouri Veterinary Health Center Small Animal Clinic Intensive Care Unit and healthy controls (n = 15).

Methods

Cohort study evaluating constitutive and lipopolysaccharide (LPS)‐stimulated TNF‐α, IL‐6, and IL‐10 production, phagocytosis of opsonized E. coli and respiratory burst capacity after opsonized E. coli or phorbol 12‐myristate 13‐acetate (PMA) stimulation, peripheral blood lymphocyte phenotype, and monocyte expressions of HLA‐DR and TLR‐4.

Results

Lipopolysaccharide‐stimulated leukocyte TNF‐α (median, Q1, Q3; CI, 49, 49, 120; control, 655, 446, 1174 pg/mL; P = < 0.001), IL‐6 (median, Q1, Q3; CI, 49, 49, 64; control, 100, 49, 166 pg/mL; P = 0.029), and IL‐10 (CI, 49, 49, 56; control, 96, 49, 203 pg/mL; P = 0.014) production and both E. coli (median, Q1, Q3; CI, 60.5, 43, 88.5; control, 86.6, 81, 89.2%; P = 0.047) and PMA (CI, 40, 11.7, 70; control, 93, 83, 97.6%; P = < 0.001)‐stimulated respiratory burst capacity significantly decreased in CI dogs. Percentage of monocytes expressing TLR‐4 greater in the CI dogs (median, Q1, Q3; CI, 46.9, 24.3, 64.2; control, 16.4, 9.4, 26.2%; P = 0.005).

Conclusion

These findings suggest dogs with CI develop immune system alterations that result in reduced respiratory burst function and cytokine production despite upregulation of TLR‐4.

Cytokine Concentrations Measured by Multiplex Assays in Canine Peripheral Blood Samples

Cytokines are known to play important roles in a wide range of pathologic conditions spanning all organ systems in every species studied. As our knowledge of the physiology of individual cytokines expands and our ability to measure multiple cytokines in smaller biological samples increases, we gain more insight into the significance and function of each cytokine and the importance of cytokine networks. Previous studies that reported measurements of cytokine concentrations from serum or plasma in dogs with infectious, autoimmune, metabolic, endocrine, and neoplastic diseases yield an appreciation for the complexity of cytokine control and potential applications for cytokine measurements in the diagnosis, prognosis, and therapy of a variety of disease conditions. In this review, we highlight the benefits of multiplex cytokine analysis, summarize clinical and experimental reports that have used this technology in dogs, and discuss the strengths and limitations of data analysis for the interpretation of results in these studies. We describe how differences in technical acuity, data reporting tactics, statistical analysis, study population selection criteria, and cross-sectional experimental design methods may affect interpretation of results from this technology. We also suggest methods for analysis in future studies, such as reporting median fluorescence intensity values, analyzing the proportion of patients above population medians, and performing longitudinal studies.