Dysfunction In Dogs Research Articles

Investigation of adrenal and thyroid gland dysfunction in dogs with ultrasonographic diagnosis of gallbladder mucocele formation.

Gallbladder mucocele formation is an emerging disease in dogs characterized by increased secretion of condensed granules of gel-forming mucin by the gallbladder epithelium and formation of an abnormally thick mucus that can culminate in obstruction of the bile duct or rupture of the gallbladder. The disease is associated with a high morbidity and mortality and its pathogenesis is unknown. Affected dogs have a significantly increased likelihood of concurrent diagnosis of hyperadrenocorticism, hypothyroidism, and hyperlipidemia. Whether these endocrinopathies represent coincidental primary disease processes that exacerbate gallbladder mucocele formation in predisposed dogs or reflect a concurrent disruption of endocrine and lipid metabolism is unclear. In this study, we investigated a hypothesis that dogs with gallbladder mucocele formation would have a high prevalence of occult and atypical abnormalities in adrenal cortical and thyroid gland function that would suggest the presence of endocrine disruption and provide deeper insight into disease pathogenesis. We performed a case-control study of dogs with and without ultrasonographic diagnosis of gallbladder mucocele formation and profiled adrenal cortical function using a quantitative mass spectrometry-based assay of serum adrenal-origin steroids before and after administration of synthetic cosyntropin. We simultaneously profiled serum thyroid hormone concentrations and evaluated iodine sufficiency by measurement of urine iodine:creatinine ratios (UICR). The studies were complemented by histological examination of archival thyroid tissue and measurements of thyroid gland organic iodine from dogs with gallbladder mucocele formation and control dogs. Dogs with gallbladder mucocele formation demonstrated an exaggerated cortisol response to adrenal stimulation with cosyntropin. A prevalence of 10% of dogs with gallbladder mucocele formation met laboratory-based criteria for suspect or definitive diagnosis of hyperadrenocorticism. A significantly greater number of dogs with gallbladder mucocele formation had basal serum dehydroepiandrosterone (DHEAS) increases compared to control dogs. A high percentage of dogs with gallbladder mucocele formation (26%) met laboratory-based criteria for diagnosis of hypothyroidism, but lacked detection of anti-thyroglobulin antibodies. Dogs with gallbladder mucocele formation had significantly higher UICRs than control dogs. Examination of thyroid tissue from an unrelated group of dogs with gallbladder mucocele formation did not demonstrate histological evidence of thyroiditis or significant differences in content of organic iodine. These findings suggest that dogs with gallbladder mucocele formation have a greater capacity for cortisol synthesis and pinpoint DHEAS elevations as a potential clue to the underlying pathogenesis of the disease. A high prevalence of thyroid dysfunction with absent evidence for autoimmune thyroiditis suggest a disrupted thyroid hormone metabolism in dogs with gallbladder mucocele formation although an influence of non-thyroidal illness cannot be excluded. High UICR in dogs with gallbladder mucocele formation is of undetermined significance, but of interest for further study.

Use of 2-dimensional speckle-tracking echocardiography to assess left ventricular systolic function in dogs with systemic inflammatory response syndrome.

BackgroundEarly identification of systolic dysfunction in dogs with systemic inflammatory response syndrome (SIRS) potentially could improve the outcome and decrease mortality.ObjectiveTo compare 2‐dimensional speckle tracking (2D‐STE) with 2‐dimensional (2D) and M‐mode echocardiography in the evaluation of systolic function in SIRS dogs.AnimalsSeventeen SIRS and 17 healthy dogs.MethodsProspective observational case‐control study. Each dog underwent physical examination, conventional echocardiography, 2D‐STE, and C‐reactive protein measurement.ResultsDogs with SIRS had lower 2D‐STE ejection fraction (X4D‐EF; 44 ± 8 versus 53 ± 8; P = .003), endocardial global longitudinal strain (ENDO‐G‐Long‐St; −14.6 ± 3.2 versus −18.5 ± 4.1; P = .003), and normalized left ventricular diameter in diastole (1.38 ± 0.25 versus 1.54 ± 0.17; P = .04) and systole (0.85 ± 0.18 versus 0.97 ± 0.11; P = .03) as compared to healthy dogs. Simpson method of disks (SMOD) right parasternal EF (55 ± 9 versus 60 ± 6; P = .07) and end systolic volume index (ESVI; 23 ± 10 versus 21 ± 6; P = .61), SMOD left apical EF (59 ± 9 versus 59 ± 6; P = .87) and ESVI (20 ± 8 versus 22 ± 6; P = .25), fractional shortening (FS; 34 ± 5 versus 33 ± 4; P = .39), M‐mode EF (64 ± 7 versus 62 ± 5; P = .35), and ESVI (23 ± 11 versus 30 ± 9; P = .06) were not significantly different between SIRS and control group, respectively.Conclusion and Clinical ImportanceSpeckle tracking X4D‐EF and ENDO‐G‐Long‐St are more sensitive than 2D and M‐Mode FS, EF, and ESVI in detecting systolic impairment in dogs with SIRS.

Effect of inflammatory marker activity after intra-articular injection of autologous platelet-rich plasma in dogs with osteoarthritis

Osteoarthritis (OA) is a common cause of lameness, pain, and dysfunction in dogs. To determine the levels of interleukin (IL) (IL-1β, IL-6, IL-10), tumor necrosis factor (TNF)-α, and prostaglandin E2 (PG-E2) in the synovial fluid after intra-articular injection of an autologous platelet-rich plasma concentrate to treat dogs with osteoarthritis. Twenty dogs with osteoarthritis (OA) were used as a materials. Fourteen dogs were used as a platelet-rich plasma (PRP) treatment group and 6 dogs were used as a control (0.9 % NaCl). PRP was obtained by the double centrifuge method. Affected joints were examined by radiography and ultrasonography. Lameness and pain severity were evaluated by attending clinicians. Samples were collected under sterile conditions at pre-treatment, days 1, 3, 5, 7, 15, and weeks 4, 8, and 12. The marker levels were determined by an enzyme-linked immunosorbent assay. No adverse effects of the injection of platelet concentrate or saline solution were observed. No significant differences were found in the Hudson Visual Analog Scale and Canine Brief Pain Inventory scores between weeks 0, 4, and 12 in the control dogs. No significant changes were observed in IL-1β, IL-6, IL-10, TNF-α, and PG-E2 levels (P>0.05) in synovial fluid from the PRP treatment group compared to synovial fluid from the control group, although fluctuations in parameter levels were observed in both groups. Despite some variable results in inflammatory parameters, clinical improvement was recorded in the PRP-treated group. PRP injection could be an effective and safe method for treatment of dogs with osteoarthritis.

Evaluation of Hemostatic Parameters in Tumor-Bearing Dogs

Background: Hemostatic alterations are commonly detected in canine cancer patients. However, few studies have described hemostatic dysfunction in dogs with different tumor subtypes. In Veterinary Medicine, the state of hypercoagulability is hardly diagnosed alive, since laboratory exams for evaluate hemostatic function are not always requested. Due to importance of homeostatic disorders in cancer patients, this study aimed to evaluate hemostatic alterations such as platelet count, activated partial thromboplastin time (aPTT), prothrombin time (PT) and fibrinogen in tumor-bearing dogs.Materials, Methods & Results: From the 55 dogs evaluated, 30 had mammary carcinoma, 6 visceral hemangiosarcoma, 9 high-grade cutaneous mast cell tumor and 10 multicentric lymphoma. The results were compared to a control group composed by 10 Beagle dogs. Thrombocytosis was observed in 26.6% (8/30) of mammary carcinoma group and thrombocytopenia in 10% (3/30). The patients with hemangiosarcoma and mast cell tumor did not reveal thrombocytosis, however, thrombocytopenia was present in 16.6% (1/6) and 33% (3/9), respectively. Three dogs with multicentric lymphoma showed thrombocytopenia and other three showed thrombocytosis. From patients with thrombocytosis, one was classified as severe thrombocytosis (1077 x 10³/µL). Therefore, there were no statistically significant associations between neoplasia group with control group (P > 0.05). Regarding the aPTT and PT evaluation, mammary carcinoma (P = 0.0005), hemangiosarcoma (P = 0.033) and mast cell tumor (P = 0.012) patients showed statistical difference for aPTT, while the evaluation for PT was not significant (P > 0.05). We grouped all patients as a “tumor group” and compared to the control group. It was possible to observe increased aPTT and PT in 89% (49/55) and 50.90% (28/55) respectively, in tumor group compared to normal. A total of 47.27% (n = 26) of the patients with tumors presented increased aPTT and PT concomitantly. In the present study, 14.54% of the patients presented elevated levels of fibrinogen associated with increased aPTT. However, only the mast cell tumor group was statistically significant (P = 0.043).Discussion: Hemostatic alterations can be found in dogs with cancer and when these alterations occurs, can be directly associated with tumoral non-invasive actions called as paraneoplastic syndrome. However, the hemostatic paraneoplastic syndrome is poorly reported in veterinary medicine, with limited number of papers describing this condition. Our results indicated that the presence of thrombocytosis in patients with tumors could be related with the production of granulocytemacrophage colony stimulating factors (GM-CSF) and IL-6 by tumor cells. A total of 26 patients with tumors presented increased aPTT and PT concomitantly, confirming that hemostatic dysfunction is a common alteration in dogs with neoplasia. However, despite alterations in coagulation parameters, there were no clinical manifestations of bleeding such as petechial or bruising in these patients. The increased fibrinogen and aPTT can be caused by a systemic inflammatory reaction mediated by pro-inflammatory cytokines produced by tumors cells. Based on that, 14.54% of the animals presented elevated levels of fibrinogen associated with elevated aPTT suggesting that these patients are associated with systemic inflammation and tumor progression. This study suggested that bearing-tumors patients shows important hemostatic dysfunctions, elucidating the clinical importance of these results in veterinary medicine.

Renal perfusion parameters measured by contrast-enhanced ultrasound in healthy dogs demonstrate a wide range of variability in the long-term.

Contrast-enhanced ultrasound may be helpful for detecting early renal microvascular damage and dysfunction in dogs. However, before this noninvasive imaging method can be tested as an early-stage screening tool in clinical patients, an improved understanding of long-term variation in healthy animals is needed. In this prospective, secondary, longitudinal, serial measurements study, variability of contrast-enhanced ultrasound renal perfusion parameters was described for eight healthy dogs, using seven time points and a period of 83weeks. Dogs were sedated with butorphanol (0.4mg/kg), and contrast-enhanced ultrasound of each kidney was performed after an intravenous bolus injection of a microbubble contrast agent (0.04mL/kg). Time-intensity curves were created from regions-of-interest drawn in the renal cortex and medulla. Intensity-related parameters representing blood volume and time-related parameters representing blood velocity were determined. A random-effects model using restricted maximum likelihood was used to estimate variance components. Within-dog coefficient of variation was defined as the ratio of the standard deviation over the mean. Time-related parameters such as time-to-peak, rise and fall time had lowest within-dog variability. Intensity-related parameters such as peak enhancement, wash-in and wash-out area under the curve, total area under the curve, and wash-in and washout rates had high within-dog variability (coefficient of variation>45%). Authors therefore recommend the use of time-related parameters for future studies of renal perfusion. Within-dog variability for bilateral kidney measurements was extremely low, therefore contrast-enhanced ultrasound may be particularly useful for detecting unilateral changes in renal perfusion. Future studies are needed to compare contrast-enhanced ultrasound findings in healthy dogs versus dogs with renal disease.

Glomerular and tubular kidney damage markers in canine babesiosis caused by Babesia canis

Canine babesiosis is a tick-borne disease caused by the haemoprotozoan parasites of the genus Babesia. The aim of this study was to assess renal dysfunction in dogs with babesiosis caused by B. canis, using serum and urinary markers for both glomerular and tubular dysfunction. Assays previously not validated for use in canine samples were validated and the potential interference of haemoglobin, lipids and bilirubin with these analyses was additionally considered.In this study 42 dogs naturally infected with B. canis and 14 healthy dogs were included. Dogs with babesiosis were divided into 3 groups: group A consisted of 9 non-azotemic dogs with normal urine protein to creatinine ratio (UPC < 0.5), group B of 27 non-azotemic dogs with UPC > 0.5 and group C of 6 azotemic dogs with UPC > 2. The concentrations of urinary immunoglobin G (IgG), retinol binding protein (RBP), uromodulin, kidney injury molecule – 1 (KIM-1), and serum symmetric dimethylarginine were measured by ELISA assays, while urinary albumin and N-acetyl-b-D-glucosaminidase (NAG) were evaluated by an immunoturbidimetric and enzymatic colorimetric assay, respectively. Urinary markers were normalized to urine creatinine concentration.All tested markers, with exception of uromodulin, showed significant differences between dogs with babesiosis and healthy dogs, and also showed strong or very strong positive correlation with UPC. Increases of urinary albumin and IgG suggested glomerular damage, and increases of KIM-1, RBP and NAG proximal tubular damage in dogs with babesiosis. They demonstrated clear advantages compared to conventional parameters by showing earlier changes in detecting renal damage.

The effect of ammonia on canine polymorphonuclear cells.

Hyperammonaemia is a common complication of liver disease in dogs. High concentrations of ammonia can be detrimental to dogs with liver disease for several reasons, notably by causing hepatic encephalopathy (HE) which describes the wide range of neurological abnormalities ranging from altered behaviour to seizures that are well recognised complications in dogs with hepatic disorders. In human patients with liver disease, hyperammonaemia has also been linked to the development of other systemic complications such as dysregulation of the innate immune system. In contrast, the effects of hyperammonaemia on the canine innate immune system is currently unknown. The aim of this study was to investigate the effects of ammonia on the oxidative burst activity of canine polymorphonuclear cells in vitro. Blood obtained from healthy dogs (n = 8) was incubated with escalating concentrations of ammonia ranging from 0 to 250μM, and the percentage of cells experiencing an oxidative burst was evaluated using a commercial kit (Phagoburst™) and flow cytometry. The spontaneous oxidative burst was evaluated without stimulation and also following stimulation with E coli. The pH of the blood was also measured at the differing ammonia concentrations. There was an increase in the percentage of cells experiencing a spontaneous oxidative burst from ammonia concentrations of 125μM (p = <0.05) and above (p = <0.01), with a 4.9 fold increase at 200μM (p = < 0.001). In those cells stimulated with E coli, incubation with increasing ammonia concentrations did not result in a significant difference in oxidative burst from baseline (p = 0.953). There was no statistically significant difference between the pH of the blood at the various ammonia concentrations (p = 0.2) suggesting that the difference in spontaneous oxidative burst was due to the ammonia rather than simply a change in pH conditions. In summary, the spontaneous oxidative burst of neutrophils was significantly increased from baseline. This supports a potential role of ammonia in contributing to innate immune system dysfunction in dogs with liver disease, and may present a future therapeutic target.

Urinary cystatin C as biomarker for identification of kidney disease in dogs

The aim of the study was to identify urinary biomarker for early detection of renal dysfunction in dogs. Paired blood and urine samples were analysed from dogs classified on the basis of International Renal Interest Society (IRIS) staging system. Serum biochemistry revealed a highly significant increase in blood urea nitrogen and creatinine levels in dogs with kidney disease. Urinalysis also revealed a highly significant increase in the level of urinary protein and urinary protein creatinine (UPC) ratio in dogs with kidney disease. A highly significant decrease in urinary creatinine and specific gravity level was also present in all groups of dogs with kidney disease. The SDS-PAGE of urinary proteins obtained from dogs with renal failure revealed the presence of low molecular weight (LMW) proteins of 14.7 KDa. This protein was identified as cystatin C protein by Immunoblotting using anti-cystatin C antibody and it has been suggested as biomarker for the diagnosis of renal disease.

Cognitive dysfunction in naturally occurring canine idiopathic epilepsy.

Globally, epilepsy is a common serious brain disorder. In addition to seizure activity, epilepsy is associated with cognitive impairments including static cognitive impairments present at onset, progressive seizure-induced impairments and co-morbid dementia. Epilepsy occurs naturally in domestic dogs but its impact on canine cognition has yet to be studied, despite canine cognitive dysfunction (CCD) recognised as a spontaneous model of dementia. Here we use data from a psychometrically validated tool, the canine cognitive dysfunction rating (CCDR) scale, to compare cognitive dysfunction in dogs diagnosed with idiopathic epilepsy (IE) with controls while accounting for age. An online cross-sectional study resulted in a sample of 4051 dogs, of which n = 286 had been diagnosed with IE. Four factors were significantly associated with a diagnosis of CCD (above the diagnostic cut-off of CCDR ≥50): (i) epilepsy diagnosis: dogs with epilepsy were at higher risk; (ii) age: older dogs were at higher risk; (iii) weight: lighter dogs (kg) were at higher risk; (iv) training history: dogs with more exposure to training activities were at lower risk. Impairments in memory were most common in dogs with IE, but progression of impairments was not observed compared to controls. A significant interaction between epilepsy and age was identified, with IE dogs exhibiting a higher risk of CCD at a young age, while control dogs followed the expected pattern of low-risk throughout middle age, with risk increasing exponentially in geriatric years. Within the IE sub-population, dogs with a history of cluster seizures and high seizure frequency had higher CCDR scores. The age of onset, nature and progression of cognitive impairment in the current IE dogs appear divergent from those classically seen in CCD. Longitudinal monitoring of cognitive function from seizure onset is required to further characterise these impairments.

Immune Function in Critically Ill Dogs.

BackgroundPeople with critical illness (CI) commonly develop various forms of immune dysfunction, however, there is limited information concerning immune dysfunction in dogs with CI.HypothesisThe immune response in CI dogs differs from that of healthy dogs.AnimalsImmunologic variables were compared between 14 dogs with CI, defined as APPLEfast score of >20 points, admitted to the University of Missouri Veterinary Health Center Small Animal Clinic Intensive Care Unit and healthy controls (n = 15).MethodsCohort 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.ResultsLipopolysaccharide‐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).ConclusionThese findings suggest dogs with CI develop immune system alterations that result in reduced respiratory burst function and cytokine production despite upregulation of TLR‐4.

Evaluation of Hemostatic Function with Thromboelastography in Dogs with Hypercoagulable Diseases

Thromboembolic complications are increasing in veterinary medicine. Thromboelastography (TEG) is a more comprehensive method for assessing the clotting process than standard plasma-based coagulation tests. This study compared the ability of TEG and standard coagulation tests to analyze the overall hemostatic state of dogs. The study involved 40 dogs with underlying diseases that predispose to hypercoagulability, including neoplasia, hyperadrenocorticism, immune-mediated diseases, gastrointestinal diseases, and protein-losing nephropathies and enteropathies, and 20 healthy dogs. Their overall hemostatic functional state was evaluated by TEG and routine coagulation assays, including activated partial thromboplastin time, prothrombin time, platelet count, and D-dimer concentration. TEG analysis showed significant differences in clot formation time, α angle, and maximum amplitude (MA) between diseased and control dogs (P ＜ 0.001 each). Increased MA was the most frequent abnormality on TEG and was indicative of hypercoagulability. TEG was useful in detecting hemostatic dysfunction in dogs with diseases associated with hypercoagulability. Dogs with TEG tracings indicative of hypercoagulability are likely to be in procoagulant states. Future prospective studies are needed to evaluate whether TEG tracings indicative of hypercoagulability are predictive of thrombosis in dogs.

Rhoptry protein 5 (ROP5) Is a Key Virulence Factor in Neospora caninum.

Neospora caninum, of the Apicomplexa phylum, is a common cause of abortions in cattle and nervous system dysfunction in dogs. Rhoptry proteins of Apicomplexa play an important role in virulence. The objectives of this study were to study functions of NcROP5 in N. caninum by deleting the NcROP5 gene from the wild Nc-1 strain. We selected NcROP5 in ToxoDB and successfully constructed an NcROP5 gene-deleted vector, pTCR-NcROP5-CD KO. Then we screened the NcROP5 knockout strains (ΔNcROP5) at the gene, protein and transcription levels. Plaque assay, host cell invasion assay and intracellular proliferation test showed that the ΔNcROP5 strain had less plaque space, weakened invasion capacity and slower intracellular growth. Animal testing showed significantly lower cerebral load of ΔNcROP5 than the load of the Nc-1 strain, as well as a loss of virulence for the ΔNcROP5 strains. Phenotypic analyses using the label-free LC-MS/MS assay-based proteomic method and KEGG pathway enrichment analysis showed a reduction of NcGRA7 transcription and altered expression of multiple proteins including the apicomplexan family of binding proteins. The present study indicated that ROP5 is a key virulence factor in N. caninum in mice. The proteomic profiling of Nc-1 and ΔNcROP5 provided some data on differential proteins. These data provide a foundation for future research of protein functions in N. caninum.

Establishment of a cell line for assessing drugs as canine P-glycoprotein substrates: proof of principle.

P-glycoprotein (P-gp), encoded by the ABCB1 (MDR1) gene, dramatically impacts drug disposition. P-gp is expressed in the intestines, biliary canaliculi, renal tubules, and brain capillaries where it functions to efflux substrate drugs. In this capacity, P-gp restricts oral absorption, enhances biliary and renal excretion, and inhibits central nervous system entry of substrate drugs. Many drugs commonly used in veterinary medicine are known substrates for canine P-gp (vincristine, loperamide, ivermectin, others). Because these drugs have a narrow therapeutic index, defective P-gp function can cause serious adverse drug reactions due to enhanced brain penetration and/or decreased clearance. P-gp dysfunction in dogs can be intrinsic (dogs harboring ABCB1-1Δ) or acquired (drug interactions between a P-gp inhibitor and P-gp substrate). New human drug candidates are required to undergo assessment for P-gp interactions according to FDA and EMA regulations to avoid adverse drug reactions and drug-drug interactions. Similar information regarding canine P-gp could prevent adverse drug reactions in dogs. Because differences in P-gp substrates have been documented between species, one should not presume that human or murine P-gp substrates are necessarily canine P-gp substrates. Thus, our goal was to develop a cell line for assessing drugs as canine P-gp substrates.

Proportion recovery and times to ambulation for non-ambulatory dogs with thoracolumbar disc extrusions treated with hemilaminectomy or conservative treatment: A systematic review and meta-analysis of case-series studies

Thoracolumbar intervertebral disc extrusion is a common cause of spinal cord dysfunction in dogs. Peer-reviewed studies reporting treatment of predominantly chondrodystrophic dogs with disc extrusion with loss of ambulation with either hemilaminectomy or conservative treatment (rest, analgesics and anti-inflammatories) were evaluated in a systematic review of the literature.Generally, the level of evidence available was low with no controlled studies and only case series available. In the meta-analysis, there was a clear trend to a greater proportion of dogs recovering and returning faster to ambulation for dogs treated with hemilaminectomy than for conservatively treated dogs. The mean proportions that recovered for neurological grades 3, 4 and 5 were 93, 93 and 61% for those treated with hemilaminectomy, and 79, 62 and 10% for those treated conservatively (Grade 3 – non-ambulatory paraparetic dogs; grade 4 – paraplegic dogs with intact deep pain perception; grade 5 – paraplegic dogs without intact deep pain perception). Due to the use of case series, these results represent between-study comparisons, thereby increasing the risk of selection bias and other biases. Data presented in this review support the current recommendations for surgical management of non-ambulatory dogs with disc-extrusion, but controlled clinical studies comparing outcomes are necessary to confirm these findings.

Abstract 12980: Circulating Level of the Growth-Differentiation Factor-15 Is Increased in Dogs With Heart Failure and Normalized After Long-term Therapy With Elamipretide

Introduction: Growth-differentiation factor-15 (GDF15) is a stress-responsive cytokine produced in pathological states associated with tissue injury and inflammation. Increased level of GDF15 is an independent predictor of adverse prognosis (disease progression and mortality) in heart failure (HF). As a prognostic biomarker, GDF15 is independent of established biomarkers including BNP, troponins, or C-reactive protein (CRP). We previously showed that increased plasma levels of nt-pro BNP, tumor necrosis factor-α, interleukin-6 and CRP are normalized in dogs with HF following long-term therapy with Elamipretide (ELA, Bendavia TM ), a novel mitochondria targeting peptide. We also showed that therapy with ELA also prevents progressive LV dysfunction in dogs with HF. Hypothesis: This study tested the hypothesis that plasma level of GDF15 is increased in dogs with HF and is normalized after long-term therapy with ELA. Methods: Venous blood samples were obtained from 14 dogs at baseline (normal state) prior to induction of HF, after the induction of HF by intracoronary microembolizations but prior to any therapy and again at 3 months after initiating therapy with either subcutaneous ELA (0.5 mg/kg/day, n=7) or saline v/v (Control, n=7). Plasma levels of GDF15 were measured using a dog specific commercially available enzyme-linked immunosorbent assay (ELISA) kit (MyBiosource, San Diego, CA). Results: In untreated HF control dogs, plasma level of GDF15 was 326±32 pg/ml at baseline and increased to 744±124 pg/ml (p&lt;0.05) when dogs were in HF and remained elevated at 3 months after initiating therapy with saline (728± 77 pg/ml). In dogs treated with ELA, plasma level of GDF15 was 314±29 pg/ml at baseline, increased to 875±71 pg/ml (p&lt;0.05) when dogs were in HF and was restored to near normal levels at 3 months after initiating therapy with ELA (556±25 pg/ml, p&lt;0.05 vs. pre-treatment). Conclusions: Circulating levels of GDF15 are increased in dogs with coronary microembolizations-induced HF. Long-term treatment with ELA reverses this increase, suggesting that inflammation-mediated injury may be reduced in dogs with HF treated with ELA. Restoring GDF15 by ELA therapy may be a useful indicator of beneficial response to therapy in patients with chronic HF.

Pulmonary artery denervation improves pulmonary arterial hypertension induced right ventricular dysfunction by modulating the local renin-angiotensin-aldosterone system.

BackgroundPulmonary arterial hypertension (PAH) is commonly accompanied with the activation of the renin-angiotensin-aldosterone system (RAAS). Renal sympathetic denervation (RSD) reduces PAH partly through the inhibition of RAAS. Analogically, we hypothesized that pulmonary artery denervation (PADN) could reverse PAH and PAH-induced right ventricular (RV) dysfunction by downregulating the local RAAS activity.MethodsTwenty-five beagle dogs were randomized into two groups: control group (intra-atrial injection of N-dimethylacetamide, 3 mg/kg, n = 6) and test group (intra-atrial injection of dehydrogenized-monocrotaline, 3 mg/kg, n = 19). Eight weeks later, dogs in the test group with mean pulmonary arterial pressure (mPAP) ≥25 mmHg (n = 16) were reassigned into the sham (n = 8) and PADN groups (n = 8) by chance. After another 6 weeks, the hemodynamics, pulmonary tissue morphology and the local RAAS expression in lung and right heart tissue were measured.ResultsPADN reduced the mPAP (25.94 ± 3.67 mmHg vs 33.72 ± 5.76 mmHg, P < 0.05) and the percentage of medial wall thickness (%MWT) (31.0 ± 2.6 % vs 37.9 ± 2.8 %, P < 0.05) compared with the sham group. PADN attenuated RV dysfunction, marked with reduced atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and ratio of right ventricular to left ventricular plus septum weight [RV/(LV + S)]. Moreover, the local RAAS expression was activated in PAH dogs while inhibited after PADN.ConclusionsPADN improves hemodynamics and relieves RV dysfunction in dogs with PAH, which can be associated with the downregulating RAAS activity in local tissue.

Clinical Relevance of Cystatin C as a Renal Marker in Dogs with Chronic Mitral Valve Insufficiency

Cystatin C is a low molecular weight 13 kilodalton protein. It is known to be a more sensitive marker of glomerular filtration rate than creatinine in humans. The purpose of the present study was to demonstrate the changes of renal markers including cystatin C according to the severity of chronic mitral valve insufficiency (CMVI) and to investigate the clinical relevance of cystatin C as an early renal marker in dogs with CMVI. A retrospective study was performed to assess renal function according to International Small Animal Cardiac Health Council (ISACHC) system classification of heart failure in dogs with CMVI. Thirty seven dogs were divided into a group 1 (healthy dogs ; n = 10), a group 2 (ISACHC I ; n = 10) and a group 3 (ISACHC II-III ; n = 17). In all dogs, serum concentrations of bun (sUr), creatinine (sCr) and cystatin C (sCys-C) were measured with an automated analyzer. In dogs with CMVI, sCys-C concentrations were significantly correlated with sCr concentrations and were independent of age, BW, SBP, and sex. Renal dysfunction tended to occur more frequently as the severity of CMVI increases. In dogs with mild CMVI, only sCys-C concentrations were statistically higher than in healthy dogs. This study demonstrates the clinical relevance of sCys-C. sCys-C may be a valuable renal marker for early diagnosis of renal dysfunction in dogs with CMVI.

Serum Concentrations of Symmetric Dimethylarginine and Creatinine in Dogs with Naturally Occurring Chronic Kidney Disease.

BackgroundSerum concentrations of symmetric dimethylarginine (SDMA) detected chronic kidney disease (CKD) in cats an average of 17.0 months before serum creatinine (Cr) concentrations increased above the reference interval.ObjectivesTo report on the utility of measuring serum SDMA concentrations in dogs for detection of CKD before diagnosis by measurement of serum Cr.Animals CKD dogs (n = 19) included those persistently azotemic for ≥3 months (n = 5), dogs that were azotemic at the time of death (n = 4), and nonazotemic dogs (n = 10). CKD dogs were compared with healthy control dogs (n = 20).MethodsRetrospective study, whereby serum Cr concentrations were determined by enzymatic colorimetry and serum SDMA concentrations were determined by liquid chromatography‐mass spectrometry in dogs with necropsy confirmed CKD.ResultsSerum SDMA increased before serum Cr in 17 of 19 dogs (mean, 9.8 months; range, 2.2–27.0 months). Duration of elevations in serum SDMA concentrations before the dog developed azotemia (N = 1) or before the dog died (N = 1) was not determined. Serum SDMA and Cr concentrations were linearly related (r = 0.84; P < .001). Serum SDMA (r = −0.80) and serum Cr (r = −0.89) concentrations were significantly related to glomerular filtration rate (both P < .001).Conclusion and Clinical ImportanceUsing serum SDMA as a biomarker for CKD allows earlier detection of kidney dysfunction in dogs than does measurement of serum Cr. Earlier detection might be desirable for initiating renoprotective interventions that slow progression of kidney disease.

Evaluation of immunomodulatory effect of recombinant human granulocyte-macrophage colony-stimulating factor on polymorphonuclear cell from dogs with cancer in vitro.

The objective of this in vitro study was to evaluate the immunomodulatory effects of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on polymorphonuclear cell (PMN) function in dogs with cancer. PMNs were harvested from dogs with naturally developing cancer as a pre-clinical model to evaluate the immunomodulatory effects of rhGM-CSF on PMN phagocytic and cytotoxic functions, cytokine production and receptor expression. Some aspects of cancer-related PMN dysfunction in dogs with cancer were restored following incubation with rhGM-CSF including PMN phagocytosis, respiratory burst and LPS-induced TNF-α production. In addition, rhGM-CSF increased surface HLA-DR expression on the PMNs of dogs with cancer. These data suggests that dysfunction of innate immune response in dogs with cancer may be improved by rhGM-CSF. The results of this study provided a pathophysiologic rationale for the initiation of clinical trials to continue evaluating rhGM-CSF as an immunomodulatory therapy in dogs with cancer.

Prognostic Value of Right Ventricular Tei Index in Dogs with Myxomatous Mitral Valvular Heart Disease.

BackgroundThe right ventricular (RV) Tei index (TX) has a significant correlation with the severity of pulmonary hypertension. However, the role of RV dysfunction in dogs with myxomatous mitral valvular heart disease (MMVD) has not been addressed.ObjectivesTo investigate the correlation between right ventricular Tei‐index (RVTX) and the prognosis for dogs with MMVD.AnimalsThirty client‐owned dogs with MMVD.MethodsClinical cohort study. Dogs were divided into two groups on the basis of the onset of cardiac‐related death within 1 year of the first echocardiographic examination. Physical examination and echocardiographic variables were compared between the groups. Receiver operating characteristic (ROC) curves and multivariate logistic analysis were used to assess the comparative accuracy when identifying dogs with cardiac‐related death.ResultsThe highest accuracy was obtained for RVTX with an area under the ROC curve (AUC) of 0.95 (95% confidence interval [CI] 0.81–0.99) followed by the left atrial to aortic root ratio with an AUC of 0.91 (95% CI 0.74–0.98), peak early diastolic mitral inflow velocity with an AUC of 0.84 (95% CI 0.64–0.94), and Doppler estimates of systolic pulmonary artery pressure with an AUC of 0.84 (95% CI 0.61–0.95). According to the multivariate logistic regression analysis, RVTX was the only independent correlate of cardiac‐related death within 1 year.Conclusions and Clinical ImportanceRight ventricular Tei‐index has a strong correlation with the prognosis for dogs with MMVD. The most significant independent predictor of death was RVTX in this study.