E65 K polymorphism in KCNMB1 gene is not associated with ischaemic heart disease in Spanish patients

Hypoxia and ischemia-reperfusion: a BiK contribution?

Over the last decades, cardiovascular disease has become the primary cause of death in the Western world, and this trend is expanding throughout the world. In particular, atherosclerosis and the subsequent vessel obliterations are the primary cause of ischemic disease (stroke and coronary heart disease). Excess calcium influx into the cells is one of the major pathophysiological mechanisms important for ischemic injury in the brain and heart in humans. The large-conductance calcium-activated K+ channels (BK) are thus interesting candidates to protect against excess calcium influx and the events leading to ischemic injury. Indeed, the mitochondrial BK channels (mitoBK) have recently been shown to play a protective function against ischemia-reperfusion injury both in vitro and in animal models, although the exact mechanism of this protection is still under scrutiny. In addition, in both the plasma membrane and mitochondrial BK channel, the α-subunit itself is sensitive to hypoxia. This sensitivity is tissue specific and conferred by a highly conserved motif within an alternatively spliced cysteine-rich insert (STREX) in the intracellular C terminus of the channel. This review describes recent developments of the increasing relevance of BK channels in hypoxia and ischemia-reperfusion injury.

The KCNMB1 Glu65Lys polymorphism associates with reduced systolic and diastolic blood pressure in the Inter99 study of 5729 Danes

OBJECTIVE

The large Ca2+ and voltage-dependent potassium channel is important in regulating vascular tone in smooth muscle tissue. The rs11739136 KCNMB1 Glu65Lys polymorphism in the beta1 subunit of the Ca2+ and voltage-dependent potassium channel has, in some studies, been reported to associate with a protective effect on diastolic hypertension. The previous studies have, however, been conflicting, and the aim of the present study was to clarify the impact of the Glu65Lys polymorphism on hypertension at the population level of middle-aged people.

DESIGN

Large-scale sex-stratified case-control studies and analyses of quantitative blood pressure.

METHODS

The KCNMB1 Glu65Lys (rs11739136) polymorphism was genotyped in 5729 Danes using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of PCR-generated primer extension products.

RESULTS

In the population-based Inter99 cohort, the Glu65Lys polymorphism was associated with a 1.3% decrease in systolic blood pressure (P=0.01) and a 1.1% decrease in diastolic blood pressure (P=0.04) per Lys-allele among 2668 men. Among women, we observed no association between systolic or diastolic blood pressure and the Glu65Lys polymorphism.

CONCLUSION

If replicated, our findings suggest that the KCNMB1 Glu65Lys polymorphism associates with reduced systolic and diastolic blood pressure in middle-aged men.