Collateral Therapeutics, Inc.

Background — To test the hypothesis that increased cardiac adenylyl cyclase type VI (AC VI ) content, which results in increased cAMP generation, would increase survival in cardiomyopathy, we crossbred mice with Gq-associated cardiomyopathy and those with cardiac-directed expression of AC VI . We also assessed myocardial hypertrophy after prolonged cardiac expression of Gq versus coexpression of Gq and AC VI . Methods and Results — Three experimental groups, Gq/AC (double positive), Gq, and control (double negative), were studied. Survival was increased by cardiac-directed expression of AC VI ( P <0.0001), and Gq/AC mice had survival rates indistinguishable from control mice. Myocardial hypertrophy developed in older Gq mice but was abrogated by cardiac expression of AC VI , as documented by the ratio of ventricular weight to tibial length (Gq, 11.93±0.99 mg/mm, n=11; Gq/AC, 8.00±0.73 mg/mm, n=9; P <0.01) and by left ventricular cardiac myocyte size (Gq, 2800±254 μm 2 , n=4; Gq/AC, 1721±166 μm 2 , n=5; P <0.01). Hearts of Gq mice were dilated, and function was impaired. Concurrent expression of AC reduced end-diastolic diameter (Gq, 4.20±0.15 mm, n=12; Gq/AC, 3.68±0.12 mm, n=7; P <0.05) and increased fractional shortening (Gq, 32±1%, n=12; Gq/AC, 41±2%, n=7; P <0.001). Cardiac myocytes from Gq/AC mice showed increased forskolin-stimulated cAMP production (Gq, 3.8±1.3 fmol/cell, n=5; Gq/AC, 10.7±2.6 fmol/cell, n=6; P <0.02), documenting increased AC function. Conclusions — Cardiac-directed expression of AC VI restores myocyte AC function, improves heart function, increases cAMP generation, abrogates myocardial hypertrophy, and increases survival in Gq cardiomyopathy.

Background —We tested the hypothesis that intracoronary injection of a recombinant adenovirus encoding adenylyl cyclase type VI (AC VI ) would increase cardiac function in pigs. Methods and Results —Left ventricular (LV) dP/dt and cardiac output in response to isoproterenol and NKH477 stimulation were assessed in normal pigs before and 12 days after intracoronary delivery of histamine followed by intracoronary delivery of an adenovirus encoding lacZ (control) or AC VI (1.4×10 12 vp). Animals that had received AC VI gene transfer showed increases in peak LV dP/dt (average increase of 1267±807 mm Hg/s; P =0.0002) and cardiac output (average increase of 39±20 mL · kg −1 · min −1 ; P <0.0001); control animals showed no changes. Increased LV dP/dt was evident 6 days after gene transfer and persisted for at least 57 days. Basal heart rate, blood pressure, and LV dP/dt were unchanged, despite changes in cardiac responsiveness to catecholamine stimulation. Twenty-three hour ECG recordings showed no change in mean heart rate or ectopic beats and no arrhythmias. LV homogenates from animals receiving AC VI gene transfer showed increased AC VI protein content ( P =0.0007) and stimulated cAMP production ( P =0.0006), confirming transgene expression and function; basal LV AC activity was unchanged. Increased cAMP-generating capacity persisted for at least 18 weeks ( P <0.0002). Conclusions —Intracoronary injection of a recombinant adenovirus encoding AC provides enduring increases in cardiac function.

Vascular endothelial growth factor (VEGF) is an endothelial specific growth factor that can induce blood vessel formation.The patent claims the identification of three novel isoforms of VEGF-A, namely VEGF-A₁₃₈, VEGF-A₁₆₂ and VEGF-A₁₈₂.These novel isoforms are discussed for their potential use in the treatment of cardiovascular diseases.