ATP-sensitive potassium (KATP) channels are found in vascular smooth muscle cells and play an important role in regulating vascular function. They are also expressed in blood but their relationship with vascular function is unknown.Purpose
To investigate the relationship between levels of KATP channels in blood and vascular function in 75 healthy subjects.Methods
Levels of KATP channels were determined from blood samples by measuring levels of mRNA subunits, Kir6.1/SUR2B, using real time RT-PCR. Vascular function was assessed using (i) laser perfusion imaging to measure post-occlusive reactive hyperaemia (PORH) and (ii) brachial artery flow-mediated dilation (FMD).Results
Kir6.1 but not SUR2B, mRNA was detected in blood. Kir6.1 mRNA threshold cycles were correlated with PORH (R= -0.275, p=0.042), FMD (R= -0.359, p=0.029) and baseline skin perfusion (R= -0.308, p=0.021). Further analysis demonstrated gender specific differences where males showed significant correlations between Kir6.1 mRNA levels and PORH (R= -0.463, p=0.01) and baseline skin perfusion (R=-0.438, p=0.016) but females did not.Conclusion
The mRNA Kir6.1subunit levels in blood show a positive, significant relationship with vascular function. Levels of KATP in blood could potentially be used as blood marker for vascular function in vivo.