oxalates and Cardiomegaly

We examined the hypothesis that the angiotensin converting enzyme inhibitor ramipril at sub-antihypertensive concentrations could improve sarcoplasmic reticulum (SR) CaATPase expression and function in compensated hypertrophied rat hearts. Five weeks after abdominal aortic constriction, rats received a daily dose (50 micrograms/kg/day) of ramipril or vehicle for 4 weeks. Cardiac angiotensin-converting enzyme (ACE) activity increased with cardiac hypertrophy (CH) but returned to normal following ramipril treatment. SR CaATPase protein levels and activity decreased with CH (P < 0.05) and were normalized following ramipril treatment (P < 0.05 for protein and activity). No change in phospholamban (PLB) protein levels could be demonstrated between any of the groups. In contrast, ramipril treatment specifically increased control SR CaATPase and PLB mRNA levels by > 60% (P < 0.01) and > 30%, respectively. In the hypertrophied group, SR CaATPase increased by 35% (P < 0.05 n = 6) after ramipril treatment. Calsequestrin mRNA levels were unaffected by ramipril administration. In conclusion, ramipril normalizes SR CaATPase protein expression and function in pressure-overloaded and compensated CH. The effects of ramipril are however multifaceted, affecting RNA and protein expression differentially.

Topics: Animals; Blotting, Northern; Blotting, Western; Calcium; Calcium-Binding Proteins; Calcium-Transporting ATPases; Calsequestrin; Cardiomegaly; Carotid Arteries; Dose-Response Relationship, Drug; Guanosine Monophosphate; Immunoblotting; Male; Oxalates; Peptidyl-Dipeptidase A; Pressure; Ramipril; Rats; Rats, Sprague-Dawley; Sarcoplasmic Reticulum

A 27-year-old man with primary oxalosis and extensive visceral involvement was maintained on long-term chronic hemodialysis. He had an episode of presyncope associated with electrocardiographic findings of an erratic atrial rhythm, atrioventricular dissociation due to an accelerated junctional rhythm and right bundle branch block. Electrophysiologic studies showed irregular atrial depolarizations probably associated with multiple atrial pacemakers, atrial inexcitability, atrioventricular dissociation and infranodal conduction delay. These findings correlated well with extensive oxalate infiltration of the sinoatrial node and its approaches, the atrial preferential pathways, the approaches to the atrioventricular node, the atrioventricular node, and the His bundle and bundle branches. This is the first reported case of cardiac electrophysiologic abnormalities due to oxalate infiltration in a patient with primary oxalosis.

Topics: Adult; Atrioventricular Node; Cardiomegaly; Electrophysiology; Heart Conduction System; Heart Diseases; Humans; Intestinal Mucosa; Male; Myocardium; Oxalates; Oxalic Acid; Pleural Effusion; Sinoatrial Node

Topics: Adult; Cardiomegaly; Humans; Kidney Calculi; Male; Metabolism, Inborn Errors; Myocarditis; Nephritis, Interstitial; Oxalates; Radiology