potassium's cardioprotective mechanisms

From: Doug Skrecky (oberon@vcn.bc.ca)
Date: Sat May 23 1998 - 06:12:52 MDT


Authors
  Young DB. Lin H. McCabe RD.
Institution
  Department of Physiology and Biophysics, University of Mississippi Medical
  Center, Jackson 39216-4505, USA.
Title
  Potassium's cardiovascular protective mechanisms. [Review]
  [88 refs]
Source
  American Journal of Physiology. 268(4 Pt 2):R825-37, 1995 Apr.
Abstract
  High rates of potassium intake are associated with
  protection from cardiovascular diseases in populations consuming primitive
  diets and in vegetarians living in industrialized cultures. In studies in
  humans and in animals, a strong inverse association between
  potassium intake and hypertension and stroke has been
  described. However, acceptance of the putative protective effect has been
  limited by inadequate understanding of 1) long-term
  potassium regulation, and 2) mechanisms by which small
  changes in plasma potassium concentration may affect
  development of cardiovascular diseases. In this review, we present results
  from analyses of long-term potassium regulation that
  indicated 1) changes in potassium intake may result in
  potassium concentrations from 3.1 to 4.6 mmol/l, and 2) when
  the initial rate is below normal, potassium concentration is
  very sensitive to changes in potassium intake rate. In
  addition, we present results that provide bases for possible mechanisms by
  which potassium may protect against cardiovascular diseases:
  1) increases in potassium inhibit free radical formation
  from vascular endothelial cells and macrophages; 2) elevation of
  potassium inhibits proliferation of vascular smooth muscle
  cells; 3) platelet aggregation and arterial thrombosis are inhibited by
  elevation of potassium; and 4) renal vascular resistance is
  reduced and glomerular filtration rate is increased by elevation of plasma
  potassium. We propose that elevation of dietary
  potassium intake increases plasma potassium
  concentration, thereby inhibiting free radical formation, smooth muscle
  proliferation, and thrombus formation. As a result, the rate of
  atherosclerotic lesion formation and thrombosis will be diminished. In
  addition, we propose the increase in glomerular filtration rate will cause a
  shift in the relationship between arterial pressure and sodium excretion that
  will lead to a reduction in arterial blood pressure. By these actions, high
  levels of dietary intake of potassium could provide the
  observed protection against the cardiovascular diseases that have plagued
  humankind since we began eating a modern high-sodium,
  low-potassium diet. [References: 88]



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