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

Rigsby CS, Pollock DM, Dorrance AM - Nutr Metab (Lond) (2008)

Bottom Line: This protection includes a blood pressure independent reduction in the amount of damage caused by cerebral ischemia.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, Medical College of Georgia, 1120 15th Street, Augusta, GA 30912, USA. dorranc3@msu.edu.

ABSTRACT

Background: 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.

Methods: 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.

Results: 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 mum HK vs LK p < 0.05) and outer diameters (322 +/- 7.6 vs 305 +/- 4.8 mum 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.

Conclusion: These studies are the first to show a beneficial effect of dietary potassium in rats with normal blood pressure.

No MeSH data available.


Related in: MedlinePlus

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).
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Figure 3: 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).

Mentions: The lumen and outer diameters of the MCA from the rats fed the HK diet were significantly larger over the range of intralumenal pressures than those from rats fed the LK diet (Figure 3A and 3B). Assessment of the vessel wall thickness and the wall to lumen ratio showed there were no significant differences between the rats fed the HK and LK diets (Figure 4A and 4B), suggesting the MCA underwent outward eutrophic remodelling in response to dietary potassium supplementation. Stress strain curves were used to assess the compliance of the MCA, there was no shift in the stress strain curve for the vessels from the rats fed the HK diet compared to the rats fed the LK diet (Figure 5A), similarly, there was no change in the β-coefficient (5.80 ± 1.15 vs 5.97 ± 0.61 HK vs LK). Dietary potassium supplementation also had no effect on the distensibility of the MCA (Figure 5B). The vessel remodelling and growth indices were calculated for the HF rats at an intralumenal pressure of 80 mmHg, the remodelling index was 110.83 indicating outward remodelling in the HK rats and the growth index was -0.41, indicating no growth and a small amount of atrophy.


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

Rigsby CS, Pollock DM, Dorrance AM - Nutr Metab (Lond) (2008)

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).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2266758&req=5

Figure 3: 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).
Mentions: The lumen and outer diameters of the MCA from the rats fed the HK diet were significantly larger over the range of intralumenal pressures than those from rats fed the LK diet (Figure 3A and 3B). Assessment of the vessel wall thickness and the wall to lumen ratio showed there were no significant differences between the rats fed the HK and LK diets (Figure 4A and 4B), suggesting the MCA underwent outward eutrophic remodelling in response to dietary potassium supplementation. Stress strain curves were used to assess the compliance of the MCA, there was no shift in the stress strain curve for the vessels from the rats fed the HK diet compared to the rats fed the LK diet (Figure 5A), similarly, there was no change in the β-coefficient (5.80 ± 1.15 vs 5.97 ± 0.61 HK vs LK). Dietary potassium supplementation also had no effect on the distensibility of the MCA (Figure 5B). The vessel remodelling and growth indices were calculated for the HF rats at an intralumenal pressure of 80 mmHg, the remodelling index was 110.83 indicating outward remodelling in the HK rats and the growth index was -0.41, indicating no growth and a small amount of atrophy.

Bottom Line: This protection includes a blood pressure independent reduction in the amount of damage caused by cerebral ischemia.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, Medical College of Georgia, 1120 15th Street, Augusta, GA 30912, USA. dorranc3@msu.edu.

ABSTRACT

Background: 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.

Methods: 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.

Results: 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 mum HK vs LK p < 0.05) and outer diameters (322 +/- 7.6 vs 305 +/- 4.8 mum 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.

Conclusion: These studies are the first to show a beneficial effect of dietary potassium in rats with normal blood pressure.

No MeSH data available.


Related in: MedlinePlus