title: Cardiac alterations in furosemide-treated thiamine-deprived rats.
abstract: BACKGROUND
  Chronic administration of furosemide may induce thiamine deficiency and cause or aggravate myocardial dysfunction.
  
  
  RESULTS
  Wistar rats were divided into four groups according to food and treatment: (1) thiamine standard chow with intraperitoneal furosemide administration; (2) thiamine standard chow with intraperitoneal saline administration; (3) thiamine-deficient chow with intraperitoneal furosemide administration; and (4) thiamine-deficient chow with intraperitoneal saline administration. Thiamine status was evaluated by high-performance liquid chromatography determination in plasma, erythrocytes, and myocardium, and by erythrocyte transketolase activity and the thiamine pyrophosphate effect to recover transketolase activity. Left ventricular mass index, intramyocardial arteries-to-cardiomyocyte ratio, cardiomyocyte cross-sectional area, and cardiomyocyte nuclei number were estimated. Myocardial structure was also studied by transmission electronic microscopy. Group 3 showed significantly lower blood and myocardial thiamine levels, which was not observed in group 1. Left ventricular mass index, cardiomyocyte cross-sectional area, and intramyocardial arteries-to-cardiomyocyte ratio were smaller in thiamine-deficient and furosemide-treated rats. However, no significant variation was found in the number of cardiomyocyte nuclei among the groups. Transmission electronic microscopy showed mitochondrial alterations in the thiamine-deficient groups.
  
  
  CONCLUSIONS
  The present results indicate that furosemide administration is not the primary cause of thiamine deficiency in rats with adequate thiamine intake. Furosemide aggravates thiamine deficiency only in situations associated with insufficient thiamine intake, causing cardiac structural alterations, such as myocardial fiber hypotrophy, poor microvascularization, and mitochondrial degeneration.
authors.affiliation: Laboratory of Morphometry and Cardiovascular Morphology, Biomedical Center, State University of Rio de Janeiro, Brazil.
authors.forename: Sergio
authors.initials: S
authors.lastname: da Cunha
authors.forename: Jayme
authors.initials: J
authors.lastname: Cunha Bastos
authors.forename: João Bosco
authors.initials: JB
authors.lastname: Salles
authors.forename: Maria Cristina Costa
authors.initials: MC
authors.lastname: Silva
authors.forename: Vera Lúcia Freire
authors.initials: VL
authors.lastname: Cunha Bastos
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Mandarim-de-Lacerda
mesh_terms: D000818:Animals; D009202:Cardiomyopathies / Q000139:chemically induced* / Q000209:etiology; D004232:Diuretics / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D005665:Furosemide / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D006304:Health Status; D008297:Male; D009206:Myocardium; D009752:Nutritional Status; D051381:Rats; D017208:Rats, Wistar; D012307:Risk Factors; D013832:Thiamine Deficiency / Q000175:diagnosis* / Q000209:etiology
chemical_list: D004232:Diuretics; D005665:Furosemide