Early potassium channel blockade improves sepsis-induced organ damage and cardiovascular dysfunction

BACKGROUND AND PURPOSE

There is increasing evidence that potassium channels are involved in the cardiovascular dysfunction of sepsis. This evidence was obtained after the systemic inflammation, cardiovascular dysfunction and organ damage had developed. Here we have studied the consequences of early interference with potassium channels on development of sepsis.

EXPERIMENTAL APPROACH

Sepsis was induced by caecal ligation and puncture (CLP) or sham surgery in Wistar rats. Four hours after surgery, animals received tetraethylammonium (TEA; a non-selective potassium channel blocker) or glibenclamide (a selective ATP-sensitive potassium channel blocker). Twenty-four hours after surgery, inflammatory, biochemical, haemodynamic parameters and survival were evaluated.

KEY RESULTS

Sepsis significantly increased plasma NO_x levels, expression of inducible nitric oxide synthase (NOS-2) protein in lung and thigh skeletal muscle, lung myeloperoxidase, urea, creatinine and lactate levels, TNF-α and IL-1β, hypotension and hyporesponsiveness to phenylephrine and hyperglycemia followed by hypoglycemia. TEA injected 4 h after surgery attenuated the increased NOS-2 expression, reduced plasma NO_x, lung myeloperoxidase activity, levels of TNF-α and IL-1β, urea, creatinine and lactate levels, prevented development of hypotension and hyporesponsiveness to phenylephrine, the alterations in plasma glucose and reduced late mortality by 50%. Glibenclamide did not improve any of the measured parameters and increased mortality rate, probably due to worsening the hypoglycemic phase of sepsis.

CONCLUSIONS AND IMPLICATIONS

Early blockade of TEA-sensitive (but not the ATP-sensitive subtype) potassium channels reduced organ damage and mortality in experimental sepsis. This beneficial effect seems to be, at least in part, due to reduction in NOS-2 expression.