Mechanism and Uses of Fasudil

Fasudil is a novel intracellular calcium antagonist, with Rho-kinase inhibitory activity on arterial walls affecting vessel remodelling.

Uses

Fasudil has been used to prevent and treat vasospasm associated with SAH. Kamei et al. reported the use of fasudil in the treatment of two patients with BD using 31P-magnetic resonance spectroscopy and Xenon-CT. Treatment with fasudil at 30 or 60 mg/day orally for 8 weeks controlled the uctuating symptoms in both patients. Mental tests and imaging also improved.

Molecular mechanism

Fasudil (HA-1077) is a selective RhoA/Rho kinase (ROCK) inhibitor.ROCK is an enzyme that plays an important role in mediating vasoconstriction and vascular remodeling in the pathogenesis of pulmonary hypertension. ROCK induces vasoconstriction by phosphorylating the myosin-binding subunit of myosin light chain (MLC) phosphatase, thus decreasing MLC phosphatase activity and enhancing vascular smooth muscle contraction.

ACE expression

Angiotensin-converting enzyme (ACE) is an enzyme that catalyzes the conversion of angiotensin-I (Ang-I) to angiotensin-II (Ang-II). Ang-II is a peptide hormone which increases blood pressure by initiating vasoconstriction and aldosterone secretion. ROCK increases ACE expression and activity in pulmonary hypertension. By inhibiting ROCK with fasudil, circulating ACE and Ang-II are reduced, leading to a decrease in pulmonary vascular pressure.

eNOS expression

Endothelial nitric oxide synthase (eNOS) mediates the production of the vasodilator nitric oxide (NO). Pulmonary arterial cell cultures treated with fasudil showed a significant increase in eNOS mRNA levels in a dose dependent manner, and the half-life of eNOS mRNA increased 2-folds. These findings suggested that ROCK inhibition with fasudil increases eNOS expression by stabilizing eNOS mRNA, which contributed to an increase of NO level to enhance vasodilation.

ERK activation

The proliferative effects of ROCK on vascular endothelial cells is due to the activation of extracellular signal-regulated kinase (ERK).ERK mediates cell proliferation via the phosphorylation of p27Kip1, thus accelerating the degradation rate of p27Kip1.p27Kip1 is a cyclin-dependent kinase (CDK) inhibitor which down-regulates cell cycle by binding cyclin-CDK complex.Human pulmonary arterial smooth muscle cells treated with fasudil showed a decrease in cell proliferation in a dose-dependent manner. Fasudil also decreases ERK activities, as well as increases level of p27Kip1. This suggested that the anti-proliferative effects of fasudil is due to the decrease of ERK activities via the inhibition of ROCK.

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