Effects of racing on reticulocyte concentrations in Greyhounds

Performance of red blood cell indices for the detection of reticulocytosis in anemic and non-anemic dogs in Taiwan

Reticulocyte counts (RETIC) are considered the gold standard in detecting an erythroid bone marrow response (BMR) in anemic and non-anemic dogs. Reticulocytosis without anemia (RWA) is a potential indicator of disease. The prevalence of anemia or RWA, as well as the effectiveness of red blood cell (RBC) indices in identifying a BMR, may vary based on geographical locations and breed differences. The purpose of the study was to determine the prevalence of regenerative and nonregenerative anemia, and RWA in pet dogs of Taiwan, and to assess the sensitivity and specificity of combined increased mean cell volume and decreased mean cell hemoglobin concentration (iMCV+dMCHC) to detect reticulocytosis in this population. The final population analysis consisted of 149,076 dogs. A cross sectional, retrospective analysis of complete blood count (CBC) samples from a field of automated hematology analyzers in Taiwan from December 1, 2018 through December 31, 2020 was performed. Among 149,076 dogs, 11.8 % (n=17,600) had reticulocytosis (RETIC > 110K/µl) and 21.8 % (n=32,474) had anemia (HCT < 37.3 %). Of 32,474 anemic dogs, 17.8 % (n=5,789) had reticulocytosis. Of 116,602 dogs without anemia, 10.1 % (n=11,776) had reticulocytosis. Across all dogs, sensitivity/specificity of iMCV+dMCHC to detect BMR was 4.3 % and 99.4 %, respectively compared to RETIC. Among anemic dogs, sensitivity/specificity of iMCV+dMCHC to detect BMR was 9.8 % and 99.2 %, respectively. Among non-anemic dogs, sensitivity/specificity of iMCV+dMCHC to detect BMR was 1.6 % and 99.5 %, respectively. Therefore, most regenerative anemias and cases of RWA did not have a combined iMCV+dMCHC. To avoid overlooking potential illness, RETIC should be evaluated regardless of whether patients have anemia or not.

Expression Profiles of the Ovine IL18 Gene and Association of Its Polymorphism With Hematologic Parameters in Hu Lambs

Hematological traits are important indexes to evaluate health status and immunological conditions in human and livestock. In this study, we measured the hematologic indexes of 819 male Hu lambs and performed the descriptive statistical analysis. The results showed the coefficients of variation of partial indexes were >10%, and the heritability for mean erythrocyte volume (MCV), white blood cell count (WBC), hemoglobin concentration (HGB), hematocrit (HCT), and red blood cell (RBC) distribution-standard deviation (RDW_SD) were medium to high, ranging from 0.17 to 0.43. In addition, Interleukin 18 (IL18), as an important regulator of both innate and acquired immune responses, was selected as candidate gene and subjected to the expression profile analysis, single nucleotide polymorphism (SNP) scanning and association analysis by using quantitative real-time PCR (qRT-PCR), PCR amplification, Sanger sequencing, and KASP genotyping. The results of qRT-PCR indicated that IL18 is predominantly expressed in lymph and lung compared with that in the other tested tissues. In addition, three novel polymorphisms (g. 24991544 A > G, g. 24991651 A > G, and g. 24991749 C > T) were identified in IL18, and the three SNPs were in a strong linkage state. Therefore, only a SNP was genotyped and performed association analysis in the enlarged experimental population, the result of association analysis demonstrated that the polymorphism g. 24991651 A > G was significantly associated with RBC, MCV, MCHC, and RDW_CV. These results will provide the reference values and the novel genetic markers of hematological parameters in sheep.

Prevalence of Reticulocytosis in the Absence of Anemia in Dogs with Cardiogenic Pulmonary Edema Due to Myxomatous Mitral Valve Disease: A Retrospective Study

Myxomatous mitral valve disease (MMVD) is the most common heart disease in small breed dogs. Dogs with MMVD commonly show clinical signs of dyspnea due to cardiogenic pulmonary edema (CPE). Reticulocytosis in the absence of anemia (RAA) is a hematological finding in hypoxic conditions. We aimed to assess the prevalence of RAA in dogs with CPE due to MMVD, and evaluate whether RAA is reversible with amelioration of dyspnea. Twenty-nine client-owned dogs with CPE due to MMVD were included. Dogs who died within 6 weeks of the onset of CPE were included in the non-survival group, while the others comprised the survival group. Of the 21 dogs, RAA was observed in 17 dogs (80.9%). In the RAA group, the absolute reticulocyte count significantly decreased as CPE resolved (p < 0.001). The mean absolute reticulocyte count in the RAA group was 163.90 ± 50.77 on the first measurement and 78.84 ± 25.64 after resolution of CPE. In the RAA group, no significant differences in mean absolute reticulocyte count were observed between the survival and non-survival groups at either the first or second measurement. Our results indicate that RAA occurs in dogs with MMVD-related CPE and can resolve after resolution of CPE.

Improved Cardiovascular Tolerance to Hemorrhage after Oral Resveratrol Pretreatment in Dogs

Resveratrol has been shown to preserve organ function and improve survival in hemorrhagic shock rat models. This study investigated whether seven days of oral resveratrol could improve hemodynamic response to hemorrhage and confer benefits on risk of acute kidney injury (AKI) without inducing coagulopathy in a canine model. Twelve greyhound dogs were randomly allocated to receive oral resveratrol (1000 mg/day) or placebo for seven days prior to inducing hemorrhage until a targeted mean blood pressure of ≤40 mmHg was achieved. AKI biomarkers and coagulation parameters were measured before, immediately following, and two hours after hemorrhage. Dogs were euthanized, and renal tissues were examined at the end of the experiment. All investigators were blinded to the treatment allocation. A linear mixed model was used to assess effect of resveratrol on AKI biomarkers and coagulation parameters while adjusting for volume of blood loss. A significant larger volume of blood loss was required to achieve the hypotension target in the resveratrol group compared to placebo group (median 64 vs. 55 mL/kg respectively, p = 0.041). Although histological evidence of AKI was evident in all dogs, the renal tubular injury scores were not significantly different between the two groups, neither were the AKI biomarkers. Baseline (pre-hemorrhage) maximum clot firmness on the Rotational Thromboelastometry (ROTEM^®) was stronger in the resveratrol group than the placebo group (median 54 vs. 43 mm respectively, p = 0.009). In summary, seven days of oral resveratrol did not appear to induce increased bleeding risk and could improve greyhound dogs’ blood pressure tolerance to severe hemorrhage. Renal protective effect of resveratrol was, however, not observed.

Haematological and biochemical reference intervals in healthy racing and retired Italian Greyhounds

In view of the enormous variability of dog breeds, breed-specific reference intervals (RIs) are recommended for use in veterinary clinical decision-making. The aim of this study was to determine whether RIs of the general canine population may be applied to the Italian Greyhound (Piccoli Levrieri Italiani or PLI), and to generate breed-specific RIs, where appropriate. Sixty-three privately owned clinically healthy fasted dogs were examined. Routine haematology and biochemistry were performed on 58 enrolled patients using the ADVIA 120 haematology analyzer and the Cobas Mira system, respectively. Changes in haematological and biochemical parameters depending on sex, age and attitude (resting vs. running dogs) were investigated. The results of PLI were compared with the RIs of the general canine population. In those cases in which these RIs were not validated, new RIs were generated according to the guidelines of the American Society of Veterinary Clinical Pathology. Pre-existing RIs were considered valid based on the recommendations by the Clinical & Laboratory Standards Institute (CLSI). RIs were higher for mean corpuscular haemoglobin (MCH), mean cell haemoglobin concentration (MCHC), cell haemoglobin concentration mean (CHCM) and lower for large unstained cells (LUC). A wider discrepancy between pre-existing and newly established RIs was found for some ADVIA parameters regarding red blood cell (RBC) or reticulocyte morphology. For total protein and cholesterol the new RIs were wider than the pre-existing ones, while albumin, calcium and iron were higher. This study suggests that most of the RIs published in veterinary textbooks cannot be validated for PLIs.

Reticulocytosis in non-anaemic cats and dogs

OBJECTIVE

To evaluate the proportion of blood samples diagnosed with reticulocytosis without anaemia in cats and dogs and report the aetiology and mortality rate of affected animals.

MATERIALS AND METHODS

Retrospective multicentre study including haematological examination of 3956 cats and 11,087 dogs admitted to seven German veterinary clinics (2012 to 2014). The proportion of blood samples with reticulocytosis without anaemia was calculated, and after exclusion of multiple measurements of the same animal, clinical data were evaluated. Animals with reticulocytosis without anaemia were classified as healthy or diseased, and diseased patients were assigned to 12 disease groups. Pretreatment (i.e. non-steroidal anti-inflammatory drugs, glucocorticoids, dipyrone) was recorded.

RESULTS

The proportion of blood samples with reticulocytosis without anaemia was 3·1% (124/3956) in cats and 4·4% (492/11,087) in dogs. Overall, 1·8% (2/111) of cats and 1·5% (7/458) of dogs with reticulocytosis without anaemia were healthy. Blood loss/anaemia, cardiac/respiratory disorders, gastrointestinal disorders and inflammatory disorders as well as cancer were the most frequent underlying diseases. Pretreatment was noted in 39·5% (43/111) of cats and 42·4% (194/458) of dogs. The mortality rate was 37·8% (42/111) in cats and 29·7% (136/458) in dogs with reticulocytosis without anaemia; the median survival time in non-survivors was 1 day (range: 0 to 376 days in cats, 0 to 444 days in dogs).

CLINICAL SIGNIFICANCE

In both species, reticulocytosis without anaemia was observed in a low proportion of blood samples (dogs>cat). Though a bias towards sick animals is possible in our sample, reticulocytosis without anaemia was mainly seen in diseased animals and associated with a mortality rate of approximately one-third of patients.

Unilateral Renal Ischemia as a Model of Acute Kidney Injury and Renal Fibrosis in Cats

The objectives of this study were to define the acute and chronic effects of 1-hour unilateral in vivo renal ischemia on renal function and histology in cats. Twenty-one adult purpose-bred research cats were anesthetized, and 1 kidney underwent renal artery and vein occlusion for 1 hour. Serum creatinine and urea concentrations, urine protein:creatinine ratio, urine-specific gravity, glomerular filtration rate, hematocrit, platelet concentration and function, and white blood cell count were measured at baseline and variable time points after ischemia. Renal histopathology was evaluated on days 3, 6, 12, 21, 42, and 70 postischemia; changes in smooth muscle actin and interstitial collagen were examined. Following ischemia, whole animal glomerular filtration rate was significantly reduced (57% of baseline on day 6; P < .05). At the early time points, the ischemic kidneys exhibited severe acute epithelial necrosis accompanied by evidence of regeneration of tubules predominantly within the corticomedullary junction. At later periods, postischemic kidneys had evidence of tubular atrophy and interstitial inflammation with significantly more smooth muscle actin and interstitial collagen staining and interstitial fibrosis when compared with the contralateral control kidneys. This study characterizes the course of ischemic acute kidney injury in cats and demonstrates that ischemic acute kidney injury triggers chronic fibrosis, interstitial inflammation, and tubular atrophy in feline kidneys. These late changes are typical of those observed in cats with naturally occurring chronic kidney disease.

Responses of the human spleen to exercise

The human spleen shows a decrease in volume of around 40% early during vigorous exercise and in response to other stressful stimuli such as maximal apnoea and the breathing of hypoxic gas mixtures. Contraction seems an active response, mediated by alpha-adrenergic fibres in the splenic nerve. Given the relatively small size of the human spleen, the effect upon physical performance is likely to be small; the augmentation of total blood volume is <2%, and even taking account of other causes of haemoconcentration during vigorous exercise, the increase of haematocrit is <10%. However, one of two studies suggested that the haemoconcentration may be sufficient to cause errors in the traditional method for calculating exercise-induced changes of plasma volume. The spleen also contributes leucocytes and platelets to the general circulation as part of the "fight or flight" reaction to stressors. The mobilisation of leucocytes proceeds more slowly than that of the red cells; it depends not only upon an active contraction of the spleen, but also a modulation of leucocyte adhesion molecules. Splenectomy impairs exercise performance in horses, but human performance data are lacking; overall health effects seem minimal, and many patients live many years after removal of their spleens.