Dietary potassium supplementation improves vascular structure and ameliorates the damage caused by cerebral ischemia in normotensive rats

<p>Abstract</p> <p>Background</p> <p>Dietary potassium supplementation in hypertensive rats is cardioprotective. This protection includes a blood pressure independent reduction in the amount of damage caused by cerebral ischemia. Therefore, we hypothesized that dietary potassium supplementation would improve the outcome of ischemic stroke by improving cerebral vessel structure in normotensive rats.</p> <p>Methods</p> <p>Wistar Kyoto (WKY) rats were fed a high (HK) or low potassium (LK) diet for six weeks from six weeks of age. At the end of treatment, cerebral ischemia was induced by middle cerebral artery (MCA) occlusion and the resultant infarct was quantified and expressed as a percentage of the hemisphere infarcted (%HI). MCA structure was assessed in an additional group of rats using a pressurized arteriograph.</p> <p>Results</p> <p>The cerebral infarct was significantly smaller in rats fed the HK diet, compared to rats fed the LK diet (21 ± 5.4 vs 33.5 ± 4.8 %HI HK vs LK p < 0.05). Vessel structure was improved in WKY rats fed the HK diet as indicated by an increase in the MCA lumen (298 ± 6.3 vs 276 ± 3.9 μm HK vs LK p < 0.05) and outer diameters (322 ± 7.6 vs 305 ± 4.8 μm HK vs LK p < 0.05). Wall thickness and area were unchanged, suggesting an outward euthrophic remodelling process. The HK diet had no effect on body weight or telemetry blood pressure.</p> <p>Conclusion</p> <p>These studies are the first to show a beneficial effect of dietary potassium in rats with normal blood pressure.</p

Dietary potassium supplementation reduces the damage caused by cerebral ischemia in WKY rats

Cerebral ischemia was induced by MCA occlusion using the intralumenal suture occlusion technique and the size of the ischemic infarct was measured twenty-four hours later. The upper panel shows representative brain slices from WKY rats fed the HK and LK diets. The light area is tissue damaged by ischemia and the dark area is viable tissue. The lower panel shows the cerebral infarct size expressed as a percentage of the hemisphere damaged by ischemia (n = 6 in both groups, p < 0.05).<p><b>Copyright information:</b></p><p>Taken from "Dietary potassium supplementation improves vascular structure and ameliorates the damage caused by cerebral ischemia in normotensive rats"</p><p>http://www.nutritionandmetabolism.com/content/5/1/3</p><p>Nutrition & Metabolism 2008;5():3-3.</p><p>Published online 31 Jan 2008</p><p>PMCID:PMC2266758.</p><p></p

Dietary potassium supplementation has no effect on the vessel compliance as indicated by the stress strain curve (A) or the vessel distensibilty (B)

Arteries were mounted in a small vessel arteriograph and vessel structure was assessed as described previously. These results were used to calculate the circumferencial wall stress, wall strain and distensibility. n = 5 for the HK group and 6 for the LK group.<p><b>Copyright information:</b></p><p>Taken from "Dietary potassium supplementation improves vascular structure and ameliorates the damage caused by cerebral ischemia in normotensive rats"</p><p>http://www.nutritionandmetabolism.com/content/5/1/3</p><p>Nutrition & Metabolism 2008;5():3-3.</p><p>Published online 31 Jan 2008</p><p>PMCID:PMC2266758.</p><p></p

Dietary potassium supplementation increases the inner (A) and outer diameter (B) of the middle cerebral artery

Arteries were mounted in a small vessel arteriograph and the inner and outer diameters of the vessels were measured over a range of intralumenal pressures (20–180 mmHg) under zero flow and calcium free conditions. Results were compared by a two way repeated measures ANOVA (p < 0.05) n = 5 for the HK group and 6 for the LK group).<p><b>Copyright information:</b></p><p>Taken from "Dietary potassium supplementation improves vascular structure and ameliorates the damage caused by cerebral ischemia in normotensive rats"</p><p>http://www.nutritionandmetabolism.com/content/5/1/3</p><p>Nutrition & Metabolism 2008;5():3-3.</p><p>Published online 31 Jan 2008</p><p>PMCID:PMC2266758.</p><p></p

Dietary potassium supplementation did not alter blood pressure in the WKY rats

Blood pressure was measured by telemetry and the average day and night blood pressures are shown (n = 3 in each group).<p><b>Copyright information:</b></p><p>Taken from "Dietary potassium supplementation improves vascular structure and ameliorates the damage caused by cerebral ischemia in normotensive rats"</p><p>http://www.nutritionandmetabolism.com/content/5/1/3</p><p>Nutrition & Metabolism 2008;5():3-3.</p><p>Published online 31 Jan 2008</p><p>PMCID:PMC2266758.</p><p></p