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High dose astaxanthin lowers blood pressure and increases insulin sensitivity in rats: are these effects interdependent?

Preuss HG, Echard B, Yamashita E, Perricone NV - Int J Med Sci (2011)

Bottom Line: We also examined effects of Asta on BP during restraint stress.At the examined doses of each, captopril lowered BP in SD without influencing glucose-insulin metabolism, whereas pioglitazone favorably affected glucose-insulin metabolism while showing essentially no effects on BP.Also, Asta at higher doses lessens restraint stress, whereas, captopril and pioglitazone did not at the doses examined, even though they influenced the BP and glucose-insulin systems respectively.

View Article: PubMed Central - PubMed

Affiliation: Georgetown University Medical Center, Department of Biochemistry, Washington, DC 20057, USA. preusshg@georgetown.edu

ABSTRACT
The present investigation in Sprague-Dawley rats (SD) was designed to examine effects of astaxanthin (Asta) at different doses on elevated blood pressure (BP) and glucose-insulin perturbations produced by heavy sucrose ingestion. We also examined effects of Asta on BP during restraint stress. SD were divided into six groups each containing eight rats. All SD ate a basic diet of ground regular rat chow with sucrose added at 30% w/w. The Control group received only the basic diet containing added sucrose, while the other five groups each received the same diet with added test material: captopril, (30 mg/Kg), pioglitazone (15.0 mg/Kg), low Asta (25 mg/Kg), medium Asta (50 mg/kg) or high Asta (100 mg/Kg). Many tests were carried out to examine the mechanisms behind the effects of Asta on BP (serum ACE activity, losartan challenge, and LNAME challenge) and the glucose-insulin system (glucose tolerance, HOMA measurement, and insulin challenge). In SD, a relatively low dose of Asta decreased SBP, but produced no major changes in the glucose-insulin system simulating results from a previous study using Zucker Fatty Rats. Increasing the dose of Asta resulted in both a lowering of elevated systolic BP and enhanced insulin sensitivity determined by many different estimations. BP lowering was consistent with changes in the renin-angiotensin (RAS) and nitric oxide (NO) systems. At the examined doses of each, captopril lowered BP in SD without influencing glucose-insulin metabolism, whereas pioglitazone favorably affected glucose-insulin metabolism while showing essentially no effects on BP. Accordingly, Asta beneficially affects both sucrose-induced elevations of BP and insulin resistance at relatively high doses in SD. Also, Asta at higher doses lessens restraint stress, whereas, captopril and pioglitazone did not at the doses examined, even though they influenced the BP and glucose-insulin systems respectively.

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a) Systolic blood pressure (SBP) of SD in Control, Captopril, and Pioglitazone groups over a period of 120 days. b) SBP of SD in Control, Low, Medium and High Asta groups. Control is same in a and b. n=8 in each group. Data are expressed as mean ± SEM.
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Figure 3: a) Systolic blood pressure (SBP) of SD in Control, Captopril, and Pioglitazone groups over a period of 120 days. b) SBP of SD in Control, Low, Medium and High Asta groups. Control is same in a and b. n=8 in each group. Data are expressed as mean ± SEM.

Mentions: Both the control and treatment groups were challenged with intraperitoneal (i.p.) regular insulin. At two months, 15 minutes after regular insulin challenge, the decrease in circulating glucose levels was significantly greater in the Pioglitazone, Medium and High Asta groups compared to Control. Results were near similar when the procedure was repeated at 8 months. The only difference was that the Medium Asta group showed only a trend toward statistical significance this time. A variation of this challenge was undertaken at the two month time. With the combined challenges with insulin and glucose, the levels of circulating glucose above initial baseline at 7.5 minutes were as follows: Control 77.3 mg/dl ± 4.7 (SEM); Captopril 68.1 mg/dl ± 4.5 (SEM), Pioglitazone 59.5 mg/dl ± 3.1 (SEM); Low Asta 66.9 mg/dl ± 3.8 (SEM); Medium Asta 65.0 mg/dl ± 4.2 (SEM) and High Asta 54.9 mg/dl ±3.0 (SEM). Compared to control, these values were statistically significantly different in the Pioglitazone and High Asta groups.


High dose astaxanthin lowers blood pressure and increases insulin sensitivity in rats: are these effects interdependent?

Preuss HG, Echard B, Yamashita E, Perricone NV - Int J Med Sci (2011)

a) Systolic blood pressure (SBP) of SD in Control, Captopril, and Pioglitazone groups over a period of 120 days. b) SBP of SD in Control, Low, Medium and High Asta groups. Control is same in a and b. n=8 in each group. Data are expressed as mean ± SEM.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3039228&req=5

Figure 3: a) Systolic blood pressure (SBP) of SD in Control, Captopril, and Pioglitazone groups over a period of 120 days. b) SBP of SD in Control, Low, Medium and High Asta groups. Control is same in a and b. n=8 in each group. Data are expressed as mean ± SEM.
Mentions: Both the control and treatment groups were challenged with intraperitoneal (i.p.) regular insulin. At two months, 15 minutes after regular insulin challenge, the decrease in circulating glucose levels was significantly greater in the Pioglitazone, Medium and High Asta groups compared to Control. Results were near similar when the procedure was repeated at 8 months. The only difference was that the Medium Asta group showed only a trend toward statistical significance this time. A variation of this challenge was undertaken at the two month time. With the combined challenges with insulin and glucose, the levels of circulating glucose above initial baseline at 7.5 minutes were as follows: Control 77.3 mg/dl ± 4.7 (SEM); Captopril 68.1 mg/dl ± 4.5 (SEM), Pioglitazone 59.5 mg/dl ± 3.1 (SEM); Low Asta 66.9 mg/dl ± 3.8 (SEM); Medium Asta 65.0 mg/dl ± 4.2 (SEM) and High Asta 54.9 mg/dl ±3.0 (SEM). Compared to control, these values were statistically significantly different in the Pioglitazone and High Asta groups.

Bottom Line: We also examined effects of Asta on BP during restraint stress.At the examined doses of each, captopril lowered BP in SD without influencing glucose-insulin metabolism, whereas pioglitazone favorably affected glucose-insulin metabolism while showing essentially no effects on BP.Also, Asta at higher doses lessens restraint stress, whereas, captopril and pioglitazone did not at the doses examined, even though they influenced the BP and glucose-insulin systems respectively.

View Article: PubMed Central - PubMed

Affiliation: Georgetown University Medical Center, Department of Biochemistry, Washington, DC 20057, USA. preusshg@georgetown.edu

ABSTRACT
The present investigation in Sprague-Dawley rats (SD) was designed to examine effects of astaxanthin (Asta) at different doses on elevated blood pressure (BP) and glucose-insulin perturbations produced by heavy sucrose ingestion. We also examined effects of Asta on BP during restraint stress. SD were divided into six groups each containing eight rats. All SD ate a basic diet of ground regular rat chow with sucrose added at 30% w/w. The Control group received only the basic diet containing added sucrose, while the other five groups each received the same diet with added test material: captopril, (30 mg/Kg), pioglitazone (15.0 mg/Kg), low Asta (25 mg/Kg), medium Asta (50 mg/kg) or high Asta (100 mg/Kg). Many tests were carried out to examine the mechanisms behind the effects of Asta on BP (serum ACE activity, losartan challenge, and LNAME challenge) and the glucose-insulin system (glucose tolerance, HOMA measurement, and insulin challenge). In SD, a relatively low dose of Asta decreased SBP, but produced no major changes in the glucose-insulin system simulating results from a previous study using Zucker Fatty Rats. Increasing the dose of Asta resulted in both a lowering of elevated systolic BP and enhanced insulin sensitivity determined by many different estimations. BP lowering was consistent with changes in the renin-angiotensin (RAS) and nitric oxide (NO) systems. At the examined doses of each, captopril lowered BP in SD without influencing glucose-insulin metabolism, whereas pioglitazone favorably affected glucose-insulin metabolism while showing essentially no effects on BP. Accordingly, Asta beneficially affects both sucrose-induced elevations of BP and insulin resistance at relatively high doses in SD. Also, Asta at higher doses lessens restraint stress, whereas, captopril and pioglitazone did not at the doses examined, even though they influenced the BP and glucose-insulin systems respectively.

Show MeSH
Related in: MedlinePlus