Biomarkers in Veterinary Cardiology.pptx

Biomarkers in veterinary cardiology provide vital insight into cardiac health, disease progression, and therapeutic monitoring. A biomarker is a measurable characteristic that reflects normal biological processes, disease states, or responses to treatment. In cardiology, they complement imaging and clinical evaluation by offering early, minimally invasive, and quantitative information.

Historically, concepts of circulation and cardiac disease evolved from Hippocrates, Harvey, and Einthoven to Detweiler, the father of veterinary cardiology. Modern biomarkers are classified into traditional enzymes, cardiac-specific proteins, natriuretic peptides, cytokines, genetic markers, and novel molecular tools like microRNAs.

Pathophysiology: Cardiac disease progression involves neurohormonal alterations: sympathetic activation, RAAS upregulation, elevated ADH, endothelin, and inflammatory cytokines, all of which contribute to remodeling, fibrosis, and heart failure. Natriuretic peptides (ANP, BNP, NT-proBNP) counteract these pathways and serve as key diagnostic and prognostic biomarkers.

Conventional biomarkers include SGOT, LDH, CK-MB, and CPK, which are nonspecific but useful in acute myocardial injury. More specific cardiac proteins such as cardiac troponins (cTnI, cTnT) are gold standards for detecting cardiomyocyte injury across species. NT-proBNP and BNP are valuable for differentiating cardiac vs respiratory causes of dyspnea, assessing prognosis in mitral valve disease and dilated cardiomyopathy, and guiding therapy.

Novel markers: microRNAs (e.g., miR-30b, miR-133b), GP-BB, and asymmetric dimethylarginine (ADMA) show promise for early diagnosis, risk stratification, and monitoring cardiotoxic chemotherapy. Genetic testing detects breed-specific mutations: PDK4 in Dobermans (DCM), MBPC mutations in Maine Coons and Ragdolls (HCM), striatin in Boxers (ARVC), and PICALM in Newfoundlands (SAS).

Clinical application: Biomarkers are useful for early detection of occult cardiomyopathy, differentiation of dyspnea, prognostic prediction, and as adjuncts to imaging. Limitations include influence from extracardiac disease (renal failure, hyperthyroidism, hypertension) and need for standardized sample handling.

In conclusion, biomarkers enrich veterinary cardiology by offering rapid, objective measures of cardiac function and injury. Combined with echocardiography, radiography, and genetic testing, they improve diagnosis, prognosis, and therapeutic decision-making. Emerging tools like microRNAs and advanced immunoassays are expected to refine future practice in both canine and feline cardiology.

1. Biomarkers in Veterinary Cardiology Presented by Bhanu Pratap Singh J-20-MV-648 Department of Veterinary Surgery & Radiology Master Seminar on

2. Outline Introduction History Classification Pathophysiology Breeds Prone Old Biomarkers New Biomarkers Supplementary Diagnostic Methods Research Material

3. Introduction Biomarker - a characteristic that is objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention - Puntmann VO (2008)

4. History Hippocrates (ca 460-ca 370 BC) is considered the Father of Modern Western Medicine. . Aristotle (384-322 BC) is considered the founder of comparative anatomy. He could only dissect animals because human dissection was forbidden Claudius Galen (129-217 AD) was a Greek physician who by dissecting monkeys and pigs, gained additional knowledge used in treating injured gladiators

5. Leonardo da Vinci (from Vinci Italy, 1452-1519) has been called the “Father of Medical Illustration” Andreas Vesalius, (1514-1564) was a Flemish physician-anatomist working at the University of Padua, Italy. He is considered the “Father of Anatomy”. Wrote the first textbooks on human anatomy, De humani corporis fabrica , (the “ Fabrica ”) published in 1543

6. Girolamo Fabrizzi (1537-1619) an Italian surgeon and anatomist at the University of Padua. major contribution to the understanding of circulation was his demonstration to William Harvey of vascular “membranous folds” (valves). William Harvey ( 1578-1657) was an English physician credited by historians as the discoverer of the circulatory system even though others accurately described most of its elements earlier.

7. Leopold Auenbrugger (1722-1809) was an Austrian physician and the “Father of Percussion” Rene´- The´ophile -Hyacinthe Lae¨nnec (1781-1826) was a French physician who trained under Corvisart , learned percussion techniques, and used direct (immediate) auscultation (ear applied to the skin).

8. Stephen Hales (1677-1763) was an English minister interested in measuring aspects of nature that he felt demonstrated the “wisdom of the almighty”.

9. J.B. Auguste Chauveau (1827-v cv c1917) did the first hemodynamic cardiac catheterizations. Discoverd that raising blood pressure caused slowing of the heart rate ( Marey’s Law) was confirmed by the “ Chauveau-Marey maneuver” in which Chauveau squeezed the horse’s aorta per rectum to raise its central blood pressure, while Marey ran the recorder that showed heart rate slowing due to vagal reflex

10. Augustus D. Waller (1856-1922) was an English physician/physiologist who made photographic refinements of a capillary galvanometer and extended electrical studies in skeletal muscle to the heart

11. Willem Einthoven (1860-1927) was a physician/ physiologist in the Netherlands who was frustrated by the slow response time of mercury based capillary galvanometers, so he developed a string galvanometer in 1887 that responded quickly to electrical events

12. Louis Desliens (1879-1975) was a French veterinarian who graduated from Maisons-Alfort (Paris) in 1904 and wrote his dissertation thesis on animal cardiology and blood transfusion.

13. David K. Detweiler (1920-2009) has been called the “Father of Veterinary Cardiology”

14. www.ncbi.nlm.nih.gov/pubmed

15. Classification

16. Progression of Heart Disease to Heart Failure Neurohormonal Alterations

17. Sympathetic Nervous System Activation Increased heart rate and contractility, through the activation of the sympathetic nervous system (SNS), are the dominant compensatory mechanisms employed to combat declining cardiac performance (Mann et al,2012) Sympathetic activation increases heart rate by affecting the rate of SA nodal depolarization by stimulation of beta-adrenergic and increasing the slow inward calcium current.

18. Cardiac output increases linearly with heart rate up to a certain threshold value; thereafter, the shortened diastolic interval causes reduction in stroke volume blunting the slope of this curve (Opie et al,2004)

19. Plasma NE concentrations in human congestive heart failure (CHF) patients correlate with the severity of heart failure and are inversely related to survival (Grassi et al,2009)

20. RAAS Activation The Major Stimuli for the Release of renin from the juxtaglomerular cells of the kidney include decreased effective renal perfusion, reduced sodium reabsorption by the renal tubules, and beta1-adrenergic stimulation. ( Griendling et al,1993) The half-life of circulating AT II is on the order of 1 or 2 minutes as it is rapidly hydrolyzed to inactive peptide fragments by circulating and tissue angiotensinases . In addition to its role as a potent vasoconstrictor, AT II promotes sodium and water retention via direct effects on the renal tubules and indirectly by stimulating aldosterone production and release from the adrenal glands (Weber KT, 2001)

21. Of particular interest is the emerging role of aldosterone as a mediator of inflammation, fibrosis, and other biological processes, such as oxidative stress, involved in pathologic remodeling in the vasculature, kidney, and heart. (Rocha et al,2002)

22. Natriuretic Peptides Atrial and brain (b-type) natriuretic peptides, ANP and BNP, released from the heart, and c-type natriuretic peptide, located mainly in the vasculature, play important regulatory roles in the circulation and provide balance to the vasoconstrictive and sodium retaining agents. ( Vikstrom et al,1998) The physiologic actions of ANP and BNP generally oppose those exerted by the RAAS (de lemos et al, 2003)

23. Antidiuretic Hormone (ADH) Increased levels of circulating ADH have been documented in dogs with dilated cardiomyopathy and chronic degenerative valve disease, but no observations have yet been reported in cats. ( Tidholm et al , 2005)

24. Endothelin Vascular tone is modulated by the endothelium-derived vasodilators, nitric oxide and prostacyclin, and by the complex actions of the potent endothelium-derived vasoconstricting peptide, endothelin three related peptides, endothelin-1, endothelin-2, and endothelin-3 , comprise the endothelin family (Inoue A et al, 1989) Vasoconstriction of smooth muscle, increases in myocardial contractility, and aldosterone secretion are among the more prominent effects mediated by beta receptor stimulation. Chronic stimulation of ETA receptors and persistently elevated ET-1 levels cause proliferation and hypertrophy of vascular smooth muscle and myocardial hypertrophy. In addition to its direct vasoconstricting effects in heart failure , ET-1 inhibits the endogenous nitric oxide (NO) synthase inhibitor, asymmetric dimethylarginine (ADMA), and the effect can be blocked by ETA receptor antagonists ( Hocher B et al ,1997)

25. NO and Adrenomedullin Plasma levels of ADM are increased in human heart failure patients and in dogs with pacing-induced experimental heart failure. Recent studies indicate that AT II stimulates ADM production and secretion from cardiac myocytes and fibroblasts and that ACE inhibition can block this response. Thus, ADM appears to have endocrine, autocrine, and paracrine effects. ( Nishikimi T et al , 2013) ADM serves as a marker of ventricular hypertrophy but acts to attenuate myocardial hypertrophy and collagen production . It has received little attention in dogs or cats with naturally-occurring heart disease which is likely to change because there is increasing interest in it as a possible therapeutic agent

26. Cytokine and Integrin Signalling Increased production and elevated plasma concentrations of proinflammatory cytokines, including interleukin-1, interleukin-6, and tumor necrosis factor alpha (TNF-alpha), have been identified in huma patient with chronic heart failure and are regarded as important negative prognostic indicators (Nagai T et al ,2012) Increased TNF-alpha levels act to depress myocardial function, and chronic elevations of TNF-alpha promote apoptosis unfortunately. ( Krown KA et al ,1996) Clinical trials of agents blocking the actions of TNF-alpha in human subjects were disappointing (Krum H, 2002)

27. Dog Breeds Prone to Cardiac Disease Newfoundland Retriever Golden Retreiver

28. Dachshunds Miniature Schnauzers

29. Cavalier King Charles Spaniels Miniature and Toy Poodles

30. Doberman Pinscher Boxer

31. Cat Breeds Prone to Cardiac Diseases Sphynx Rex

32. Ragdoll Maine Coon

33. Serum Glutamic Oxaloacetic Transaminase (SGOT) Rough correlation with the extent of the infarct and may be transiently/minimally abnormal. SGOT may be elevated Liver cell necrosis –common in congestive heart failure Skeletal muscle damage Normal values Dog -6.2-19 Cat – 6.7-11 Horse -58-94 Cattle -20-34 Sheep -79-90 Goat -43-132 Pig -8.2-21.6 ( Kaneko.J , 1971)

34. Lactic Dehydrogenase It is widely distributed throughout the body Elevated when there is increased production as neoplastic cells proliferate Strenuous exercise or muscle exertion It has wide range of normal values C atalyses the conversion of pyruvate to lactate Peaks at 72 hours LDH Isoenzymes: LDH 1 – found mainly in cardiac muscle , along with smaller amount of LDH-2 It is of value in diagnosis of cardiac muscle damage LDH 3- found mainly in lung LDH 5 – mainly from liver with smaller amounts in skeletal muscle

35. LDH Values Dog – 10-35 IU/L Cat – 16-69 IU/L Horse – 41-104 IU/L Cattle- 176-365 IU/L Sheep- 60-111 IU/L goat- 31-99 IU/L Pig – 96-160 IU/L (Gale H,2000)

36. Creatinine Kinase- Myocardial Band It is relatively specific when skeletal muscle damage is not present. Peaks at 10–24 hours. Since it has a short duration, it cannot be used for late diagnosis of acute MI but can be used to suggest infarct extension if levels rise again. This is usually back to normal within 2–3 days. Normal range- 2-6 ng/ml.(Dog) ( P .Diniz,2007 )

37. Creatinine Phosphokinase(CPK) Primarily in the skeletal ,cardiac and brain. Absent in the liver Elevated in Acute myocardial infarction – occurs within 12 hr reaches a peak within 24-36 hour and returns to normal within 4 days Skeletal muscle damage greater increase Pulmonary embolism- minimal increase To differentiate between acute myocardial infarction and pulmonary embolism it is necessary to compare increases in CP and LDH Myocardial infarction – both enzymes are increased in the serum Pulmonary embolism – LDH is prominently elevated Not elevated in Liver congestion due to congestive heart failure

38. CPK Values Dog 0.2-2.6 IU/L Cat 0.4-3.4 IU/L Horse 0-3.6 IU/L Cattle 0-17 mU /mL (Dairy) 3-50 mU /mL(Feedlot) Sheep 0-2.9 IU/L Goat 0-2.5 IU/L (Andre L.F Santos, 2000)

39. NT- proBNP It is a prohormone with a 76 amino acid N-terminal inactive protein that is cleaved from the molecule to release brain natriuretic peptide. (Bhalla V et al ,2004) Both BNP and NT- proBNP levels in the blood are used for screening, diagnosis of acute congestive heart failure (CHF) and may be useful to establish prognosis in heart failure, as both markers are typically higher in patients with worse outcome ( Atisha D et al ,2004) NT- proBNP has a half-life of 120 min (Michael E et al. 2006)

40. NT pro BNP in Horse - 20.00±0.00 pg /ml ( Rezazadeh et al,2016) NT-proBNP in calves - 131.32 ± 13.1 ng/L ( Beydilli Y et al,2020)

41. Brain Natriuretic Peptide 134-amino acid preprohormone ( preproBNP ), encoded by the human gene NPPB. Removal of the 25-residue N-terminal signal peptide generates the prohormone, proBNP , which is stored intracellularly as an O-linked glycoprotein; proBNP is subsequently cleaved between arginine-102 and serine-103 by a specific convertase (probably furin or corin ) into NT- proBNP and the biologically active 32-amino acid polypeptide BNP-32, which are secreted into the blood in equimolar amounts ( Schellenberger U et al,2006) The half-life of BNP is 20 min (Michael e et al, 2006)

42. Atrial Natriuretic Peptide A 28-amino acid peptide with a 17-amino acid ring in the middle of the molecule. The ring is formed by a disulfide bond between two cysteine residues at positions 7 and 23 (Vesely DL,2013) The main function of ANP is causing a reduction in expanded extracellular fluid (ECF) volume by increasing renal sodium excretion. ANP is synthesized and secreted by cardiac muscle cells in the walls of the atria in the heart. These cells contain volume receptors which respond to increased stretching of the atrial wall due to increased atrial blood volume. The reported half-life of ANP ranges from 0.5 to 4 minutes in mice, rats, rabbits, dogs and monkeys ( Ruskoaho H,1992)

43. ANP in horse - 206.92±23.01 ng/L ( Rezazadeh et al,2016)

44. NT- proANP Pro-hormones (proANP1-126) in numerous granules in the atrial cardiomyocytes Also present in other organs, such as the pituitary, lungs, hypothalamus and kidneys ( Kokkonen et al., 2002; Hayek and Nemer , 2010). In response to atrial stretch, the pro-ANP1-126 molecule is split into an inactive NH2-terminal peptide (NT-proANP1-98) and a biologically active (COOH-terminal) ANP99-126 molecule, which are both released into the blood stream Half-life of NT- proANP is longer (55- 60 minutes), NT- proANP can be used to assess endogenous secretion of ANP (Thibault et al., 1987; Ruskoaho , 1992; Kokkonen et al., 2002).

45. ( Vekens N.V.D et al, 2012)

46. Diagnostic indications and values for use of NT- proBNP and cTnI in Dogs and Cats Occult Cardiomyopathy Cats : NT proBNP < 49pmol/l disease unlikely NT- proBNP > 100 pmol /l disease likely(echo recommended) cTnI < 0.03 ng/ml disease unlikely cTnI > 0.16 ng/ml disease likely (echo recommended) Differentiation of Respiratory Signs in Cats: NT- proBNP > 260 pmol /l CHF is more likely NT- proBNP < 49 pmol /L CHF is unlikely cTnI > 0.94ng/ml CHF is more likely cTnI <0.94 ng/ml CHF is less likely

47. Differntiation of respiratory signs in dogs : NT- proBNP > 1400pmol/l CHF IS MORE LIKELY NT- proBNP <900 PMOL/L, CHF iws unlikely cTnI : assay hindered by high degree of overlap between causes Prediction of morbidity and mortatily in dogs with MMVD : NT-pro BNP > 1500 pmol /l future CHF & mortality is likely NT-pro BNP < 1500 pmol /l future CHF is unlikely NT-pro BNP > 524 pmol /l and cTnI > 0.025 ng/ml future mortality is more likely

48. Reliable results can be obtained if aprotinin (a proteinase-inhibitor) is added to blood EDTA (ethylenediaminetetraacetic acid) samples and centrifuged at 4°C within 30 minutes. Plasma storage at -80°C is preferred until the assay is performed. Since significant ANP degradation has been shown in samples stored at -80°C for seven days , plasma samples should be assayed immediately or within a few days ( Nelesen et al., 1992)

49. Cardiac troponin T Troponin T a part of the troponin complex, which are proteins integral to the contraction of skeletal and heart muscles. binds to tropomyosin and helps position it on actin ( marieb , elaine 2004) The cardiac subtype of troponin T is especially useful in the laboratory diagnosis of heart attack because it is released into the blood-stream when damage to heart muscle occurs Cardiac troponin I Troponin I prevents myosin from binding to actin in relaxed muscle. When calcium binds to the troponin C, it causes conformational changes which lead to dislocation of troponin I. It is a useful marker in the laboratory diagnosis of heart attack.

50. Abbot Laboratories for example recommends centrifugation of serum samples (after complete clot formation) at 2500-3000 g for 10 minutes if testing is delayed for more than eight hours . According to these instructions, samples can be stored up to 72 hours at 2-8°C and up to 30 days when frozen at a maximum temperature of -10°C (Manual of the Architect STAT troponin I system, Abbott Laboratories, Abbott Park, Illinois)

51. cTnI in horse - 0.007±0.002 ng/ml ( Rezazadeh et al,2016) cTnI in calves - 0.022 ± 0.004 (ng/ml) ( Beydilli Y et al,2020) cTnI in Sheep - 0.010-0.017 μ g/L ( Karapinar T et al,2012)

52. GPI-BB Peaks at 7 hours Glycogen phosphorylase isoenzyme BB (abbreviation: GPBB) is one of the three isoforms of Glycogen Phosphorylase. This isoform of the enzyme exists in cardiac (heart) and brain tissue. Because of the blood–brain barrier, GP-BB can be seen as being specific to heart muscle. GP-BB is one of the "new cardiac markers" which are considered to improve early diagnosis in acute coronary syndrome. During the process of ischemia, GP-BB is converted into a soluble form and is released into the blood. A rapid rise in blood levels can be seen in myocardial infarction and unstable angina (Singh N, 2018)

53. Elevated Levels Conceived Myxomatous Mitral Valve Disease(MMVD) Hypertrophic cardiomyopathy(HCM) Dilated cardiomyopathy(DCM) Restrictive Cardiomyopathy(RCM) Cardiac wall stress, ischemia and cardiac cell injury Patent ductus arteriosus Congestive Heart failure Note: Biomarker concentration are correlated to radiographic and echocardiographic findings

54. Specific Indications Occult cardiomyopathy detection in suspected cat Differentiation of cardiac compared with non-cardiac causes of respiratory signs in the dog and cat Prognostic tool in dogs with MMVD or DCM Helps to clarify need for thoracic radiography or echocardiography rather than being the sole tool for clinical judgement

55. Not recommended in following : Diagnosis or staging of MMVD in dogs Routine prescreening of anesthetic case, particularly young healthy animals undergoing spay or neuter Prescreening of dogs or cats at low risk of contracting the disease.

56. Differentiation of cardiac with non-cardiac causes of repiratory signs Dogs/cats with dyspnea , tachypnea or coughing often represent a diagnostic dilemma with respect to etiology In geriatric dog with coughing most common cause is either chronic airway disease or CHF due to MMVD. Normal values of biomarkers make the presence of CHF less likely In small breed dog with coughing but without heart murmur biomarker testing is generally unnecessary as likelihood of MMVD is low

57. Note : cTnI is less useful than NTproBNP for differentiation of respiratory signs as cTnI is released secondary to cardiomyocyte injury including ischemia resulting form severe primary respiratory disease and hypoxemia

58. Effect of extracardiac disease on cardiac biomarker testing Both are dependent on renal excretion and values are elevated in patients with renal insufficiency Both can be elevated in cases of systemic hypertension, hyper thyroidism or pulmonary hypertension ( J.K.Sangster et al, 2014)

59. Technique Natriuretic testing is performed on serum or EDTA plasma Proper sampling and handling of samples is required to obtain accurate results

60. Genetic Testing Analysis of DNA for genetic abnormalities or mutations By incomplete penetrance individuals can be carriers of genetic disease Valvular and myocardial disease have more than one genetic association Homozygous individuals are at greater risk

61. Indication of Genetic Testing Confirm a suspected diagnosis Detect Carriers of disease Predict likelihood of future disease Predict response to medication or therapy

62. HCM in Maine Coon Cat Mutation in A31P affects production of Myosin Binding Protein c(MBPC) and leads to the development of idiopathic left ventricular concentric hypertrophy or HCM

63. HCM in the Ragdoll Mutation at R820W affects the production of MBPC and is associated with HCM or idiopathic left ventricular concentric hypertrophy

64. DCM in Doberman pinscher Mutation of autosomal gene that encodes for pyruvate dehydrogenase kinase 4(PDK4) affects glucose oxidation within myocardial cells and high energy phosphate production

65. ARVC in Boxer Striatin is a desomosal protein involved in the cell to cell junction. Mutaion in the autosomal gene that encodes for the protein striatin lead to ARVC in boxer breeds

66. SAS in Newfoundland Retriever Mutation in the autosomal gene that encodes for PICALM( phosphotidyl -inositol binding clathrin assembly protein) which is involv development of foetal heart and cell membrane vesicle formation ed in the

67. Technique Buccal mucosa cheek swab or whole blood The swab should be air dry and be saved from bacterial contamination 2-5 ml of EDTA vials can be used too

68. ( J.M Naylor, 2001)

69. The heart in a ventrodorsal (VD), or dorsoventral (DV), view illustrating the clockface analogy. Locations of dilation of the left auricle ( LAu ), main pulmonary artery (MPA), aortic arch (AA), and right atrium (RA) are shown. LAu , Bulge at 2 to 3 o’clock; MPA, bulge at 1 to 2 o’clock; AA, bulge at 11:30 to 12:30 o’clock; RA, bulge at 9:30 to 11:30 o’clock.

70. Assessment of a point-of-care cardiac troponin I test to differentiate cardiac fromnoncardiac causes of respiratory distress in dogs cTnI concentrations 41.5 ng/mL demonstrated high sensitivity 78% with specificity levels just above 52% in identifying dogs with cardiogenic respiratory distress. Therefore, cTnI concentration should be used in conjunction with other diagnostics not as a sole entity. However, dogs with cTnI concentrations 41.5 ng/mL with other physical exam findings such as a heart murmur are likely to be in respiratory distress from cardiac disease (Edward E. Payne et al , 2011)

71. NT- proBNP analysis may be considered a useful method in diagnosing cats presented with acute dyspnea. (S.kahty,2021) Measurement of NTproBNP and hscTnI is prognostically superior to measuring either alone . Serial measurement strategies provide additional prognostic information. (M.J. Hezzell et al,2012) NT- proBNP concentrations predicted the clinician’s decision to modify a patient’s medication s on the basis of their clinical assessment ( Asche SE et al , 2009)

72. The short-term effect of steroids administered PO was not associated with a statistically significant increase in absolute concentration of NT- proBNP ; however, the significant change in left atrial and ventricular size suggests that steroid administration increased circulating plasma volume. ( C.L.Block et al,2018) C ancer patients(dogs) receiving single agent DOX chemotherapy, selected EV-miRNA were differentially expressed with DOX treatment: miR-107 and miR-146a were downregulated whereas miR-502 was upregulated after just 2 doses of DOX. ( A.Beaumier et al,2019)

73. In LMNA mutation-related cardiac disorders e levated hsTnT level seems the earliest abnormality emerging in the course of cardiolaminopathies and may facilitate early detection of the LMNA carrier status. Circulating cardiac biomarkers, especially increased NT- proBNP level, may be helpful in arrhythmic risk stratification (P. Chmielewski et al ,2020) The thyroid status of older cats should be ascertained before interpreting NT- proBNP and CTNI concentrations ( J.K.Sangster et al, 2014)

74. cTnI,myoglobin and CK-MB could be useful to evaluate themyocardial status of heartworm-infected dogs during the adulticide treatment to monitor the possible damagecaused during the death of the worms ( E.Careton et al, 2013) miR-30b could be a potential biomarker of ACVIM stage B heart failure in Dachshunds with endocardiosis and miR-133b could be a potential biomarker of ACVIM stage C . The lack of expression or lack of significant changes in expression in 7 miRNAs which are potential biomarkers of heart diseases in humans proves that findings from human medicine are not always directly reflected in veterinary medicine. (M Hulanicka et al, 2014)

75. 4 miRNAs that were differentially expressed after administration of DOX: miR-107, miR-146a, miR-181d, and miR-502. Upregulation of miR-502 was detected before any significant changes were seen in other established biomarkers, including cTnI and echocardiographic parameters. (A. Beaumier et al,2020)

76. Assay of serum concentrations of cTnI and NTproBNP would help in confirming the FMD-induced myocarditis and predicting the survival. ( P.Mahadappa et al , 2021) T he physiological reasons for higher serum ADMA concentration and a decreased L-arginine/ADMA ratio in horses with cardiac disease remain elusive, this study demonstrates that ADMA is a promising biomarker not just in humans (A Ertelt et al, 2020)

77. Among the various indicators of cardiac damage measured in this study, cTn -I showed the highest alteration in equines suffering from theileriasis . ( S.Ahmadmpour et al, 2020) CpANP is higher in horses with mild to severe MR that was characterized by increased left heart dimensions, increased PCWP, but normal exercise capacity and absence of clinical signs of congestive heart failure (D. S. Trachsel et al, 2014)

78. Exploration of serum cardiac troponin I as a biomarker of cardiomyopathy in southern sea otters (Enhydra lutris nereis) A significant difference in cTnI concentrations was observed between cases and both control groups, with median values of 0.279 ng/mL for cases and < 0.006 ng/mL(A cutoff value of ≥ 0.037 ng/mL) for free-ranging and managed controls. (Moriarty et al , 2020)

79. First study to report normal values of cTnT in squirrel monkeys (0.049 ng/mL) whereas concentrations of NT - proBNP were below detection limit. ( L.Locquet et al, 2020)

80. S tudy demonstrated that serum cTnI ( cut-off value disease was 0.0085 ng/m L) concentration is elevated in rhesus macaques with HCM and other types of cardiac disease as compared with control rhesus macaques. (Yu ueda et al, 2020)

81. INFLUENCE OF 8 KM TRAINING ON CARDIAC BIOMARKERS ALONGSIDE HAEMATOBIOCHEMICAL PROFILES IN RACE CAMELS The serum concentration of ctnI (<1ng/ml) did not change significantly before and after training in racing camels. (Mohammed Tharwat,2021)