Obstructive vascular disease is an important health problem in the industrialized world. Through a series of molecular genetic studies, we demonstrated that loss-of-function mutations in one elastin allele cause an inherited obstructive arterial disease, supravalvular aortic stenosis (SVAS). To define the mechanism of elastin's effect, we generated mice hemizygous for the elastin gene ( ELN ϩ / Ϫ ). Although ELN mRNA and protein were reduced by 50% in ELN ϩ / Ϫ mice, arterial compliance at physiologic pressures was nearly normal. This discrepancy was explained by a paradoxical increase of 35% in the number of elastic lamellae and smooth muscle in ELN ϩ / Ϫ arteries. Examination of humans with ELN hemizygosity revealed a 2.5-fold increase in elastic lamellae and smooth muscle.

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Low-dose vasopressin infusions increased mean arterial pressure, systemic vascular resistance, and urine output in patients with vasodilatory septic shock and hyporesponsiveness to catecholamines. The data indicate that low-dose vasopressin infusions may be useful in treating hypotension in these patients.