Impact of gender on contractile function in human skinned fibers in condition of volume-overload.

Results Female fibers achieve higher force values than male patients at the highest step of calcium concentration (pCa 4.0: 3.9 ± 0.5 mN versus 2.9 ± 0.9 mN, p 0.02). Male and female fibers show an anticyclical course when exposed to increasing steps of calcium concentrations: starting with lower force values at lower calcium concentrations in males, the steepness of pCa-force-curve is flatter compared to female counterparts (pCa 6.5 males: 1.3 ± 0.3 mN versus females 0.203 ± 0.1 mN, p 0.03 and pCa 6.0 males: 1.5 ± 0.4 mN versus females 0.3 ± 0.09 mN, p 0.09). At higher force values females achieve higher maximal forces and lower force values for males (pCa 4.0 females 3.9 ± 0.5mN versus males 2.9 ± 0.9 mN, p 0.02; and pCa 4.5 females 2.83 ± 0.3 mN versus 2.1 ± 0.1 mN, p 0.02). Calcium sensitivity, given as half maximal concentration, is achieved at pCa 5.0 in females and between 6 and 5.5 for males (p 0.04).