1 Fibrosis leads to chronic impairment of cardiac and renal function and thus reversal of existing ®brosis may improve function and survival. This project has determined whether pirfenidone, a new anti®brotic compound, and spironolactone, an aldosterone antagonist, reverse both deposition of the major extracellular matrix proteins, collagen and ®bronectin, and functional changes in the streptozotocin(STZ)-diabetic rat. 2 Streptozotocin (65 mg kg 71 i.v.)-treated rats given pirfenidone (5-methyl-1-phenyl-2-[1H]-pyridone; approximately 200 mg kg 71 day 71 as 0.2 ± 2g 1 71 drinking water) or spironolactone (50 mg kg 71 day 71 s.c.) for 4 weeks starting 4 weeks after STZ showed no attenuation of the increased blood glucose concentrations and increased food and water intakes which characterize diabetes in this model. 3 STZ-treatment increased perivascular and interstitial collagen deposition in the left ventricle and kidney, and surrounding the aorta. Cardiac, renal and plasma ®bronectin concentrations increased in STZ-diabetic rats. Passive diastolic sti ness increased in isolated hearts from STZ-diabetic rats. Both pirfenidone and spironolactone treatment attenuated these increases without normalizing the decreased +dP/dt max of STZ-diabetic hearts. 4 Left ventricular papillary muscles from STZ-treated rats showed decreased maximal positive inotropic responses to noradrenaline, EMD 57033 (calcium sensitizer) and calcium chloride; this was not reversed by pirfenidone or spironolactone treatment. STZ-treatment transiently decreased GFR and urine¯ow rates in isolated perfused kidneys; pirfenidone but not spironolactone prevented the return to control values. 5 Thus, short-term pirfenidone and spironolactone treatment reversed cardiac and renal ®brosis and attenuated the increased diastolic sti ness without normalizing cardiac contractility or renal function in STZ-diabetic rats.

No abstract

1 This study has administered pirfenidone (5-methyl-1-phenyl-2-[1H]-pyridone) or amiloride to attenuate the remodelling and associated functional changes, especially an increased cardiac stiness, in DOCA-salt hypertensive rats. body wt) without lowering systolic blood pressure. 4 Collagen deposition was signi®cantly increased in the interstitium after 2 weeks and further increased with scarring of the left ventricle after 4 weeks; pirfenidone and amiloride reversed the increases and prevented further increases. This accumulation of collagen was accompanied by an increase in diastolic stiness constant; both amiloride and pirfenidone reversed this increase. 5 Noradrenaline potency (positive chronotropy) was decreased in right atria (neg log EC50: control 6.92+0.06; DOCA-salt 6.64+0.08); pirfenidone but not amiloride reversed this change. Noradrenaline was a more potent vasoconstrictor in thoracic aortic rings (neg log EC50: control 6.91+0.10; DOCA-salt 7.90+0.07); pirfenidone treatment did not change noradrenaline potency. 6 Thus, pirfenidone and amiloride reverse and prevent cardiac remodelling and the increased cardiac stiness without reversing the increased vascular responses to noradrenaline. British Journal of Pharmacology (2002) 135, 961 ± 968

No abstract

These results demonstrate that PFD can attenuate both renal fibrosis and renal damage in this model, and suggest that PFD can be clinically useful for preventing progressive, irreversible renal failure.