Pharmacokinetics of digoxin in cattle

Prophylactic digoxin treatment reduces IL-17 production in vivo in the neonatal calf and moderates RSV-associated disease

Respiratory syncytial virus (RSV) is a leading cause of morbidity and mortality in human infants. Bovine RSV infection of neonatal calves is pathologically and immunologically similar to RSV infection in infants, and is therefore a useful preclinical model for testing novel therapeutics. Treatment of severe RSV bronchiolitis relies on supportive care and may include use of bronchodilators and inhaled or systemic corticosteroids. Interleukin-17A (IL-17) is an inflammatory cytokine that plays an important role in neutrophil recruitment and activation. IL-17 is increased in children and rodents with severe RSV infection; and in calves with severe BRSV infection. It is currently unclear if IL-17 and Th17 immunity is beneficial or detrimental to the host during RSV infection. Digoxin was recently identified to selectively inhibit IL-17 production by antagonizing its transcription factor, retinoid-related orphan receptor γ t (RORγt). Digoxin inhibits RORγt binding to IL-17 and Th17 associated genes, and suppresses IL-17 production in vitro in human and murine leukocytes and in vivo in rodent models of autoimmune disease. We demonstrate here that in vitro and in vivo digoxin treatment also inhibits IL-17 production by bovine leukocytes. To determine the role of IL-17 in primary RSV infection, calves were treated prophylactically with digoxin and infected with BRSV. Digoxin treated calves demonstrated reduced signs of clinical illness after BRSV infection, and reduced lung pathology compared to untreated control calves. Digoxin treatment did not adversely affect virus shedding or lung viral burden, but had a significant impact on pulmonary inflammatory cytokine expression on day 10 post infection. Together, our results suggest that exacerbated expression of IL-17 has a negative impact on RSV disease, and that development of specific therapies targeting Th17 immunity may be a promising strategy to improve disease outcome during severe RSV infection.

Treatment of cardiovascular disease in cattle

Cardiac diseases of cattle may involve valvular structures, myocardium, pericardium, or blood vessels and are manifested by the clinical signs of cardiac dysrhythmias, cardiac murmurs, generalized edema, muffled heart sounds, jugular venous distention, jugular venous pulsations, pulmonary edema, pleural effusion, or ascites. Digoxin, quinidine, and furosemide can be used effectively to control signs of CHF and cardiac arrhythmias. Combination antimicrobial therapy can be successful for cows with infective endocarditis and thrombophlebitis. Pericardial fluid drainage may temporarily improve cattle with traumatic pericarditis or lymphosarcoma so that short-term goals may be reached.