Fat-free milk may help ease hypertension
CM NEWS - Women who drank more fat free milk and had higher intakes of calcium and vitamin D from foods, and not supplements, tended to have a lower risk for developing hypertension or high blood pressure, according to a new study published in the American Heart Association journal, Hypertension. Read more
Acupuncture on hypertension ‘a clear effect’: landmark study
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Heartwire - A study billed as the first rigorous, randomized trial in the West to test acupuncture against a sham (fake) needle technique to treat hypertension suggests that, performed properly, acupuncture may produce blood-pressure changes on a par with monotherapy in mild to moderate hypertension.
“It’s certainly not like a wonder drug; it’s not a massive effect, but it’s a clear effect,” lead investigator Dr Frank A Flachskampf (Universitätsklinikum Erlangen, Germany) said.
Smaller randomized trials have been performed in China, with mixed results, while one randomized study in the West found no difference in blood-pressure lowering between traditional Chinese acupuncture, standardized acupuncture, and a sham procedure, the authors note. This earlier study did not use ambulatory blood-pressure measurements, believed to be superior to office-based measurements.
Results of their study are published online June 4, 2007 in Circulation.
For the study, 160 outpatients with uncomplicated, mild to moderate hypertension were randomized to six weeks of acupuncture performed by Chinese medicine practitioners, trained in China, or to a sham procedure. In both arms, patients underwent 22 sessions, each 30 minutes in length. By the end of the six weeks, 24-hour ambulatory systolic and diastolic blood pressures were significantly reduced from baseline in the acupuncture-treated patients (5.4 mm Hg and 3.0 mm Hg, respectively), and this change was also significantly different from values in the sham-treated patients, in whom no meaningful changes were seen.
After three and six months, however, the blood-pressure reductions disappeared, leading investigators to conclude that ongoing acupuncture treatments would be required to maintain the blood-pressure reductions.
“The main finding is that for the first time in a reasonably sized but still relatively small randomized study, this establishes beyond a reasonable doubt that acupuncture lowers blood pressure,” Flachskampf commented. “It’s a modest but undeniable effect on both systolic and diastolic blood pressure.”
The extent of the blood-pressure reductions are comparable to those seen with ACE-inhibitor monotherapy or aggressive lifestyle changes, including radical salt restrictions, he added.
A “demanding” alternative to drugs
Flachskampf had some caveats, acknowledging that the regular acupuncture sessions used in the study represent a significant time investment: each acupuncture session lasted 30 minutes—not including transportation and administrative time—and took place several times a week. The study subjects were also reasonably healthy, with no other major risk factors and with only mild to moderate hypertension.
“This is clearly something that would probably not work as well with very sick people or people with blood pressure at dangerous levels,” he said. “We cannot easily extrapolate to people, for example, with complicated hypertension who have had a myocardial infarction.”
Flachskampf believes, however, that acupuncture likely represents an attractive option in specific patients, particularly those averse to taking medical therapy who are open to so-called “alternative” medicine.
“This is probably only for people who somehow relate to this spiritually, who say I am profoundly against taking drugs and I’m very fond of Oriental wisdom or things like that,” Flachskampf told heartwire. “I don’t want to make a joke about this, but this certainly needs more compliance than taking two or three pills a day. It’s much more demanding.”
Unlike drugs, acupuncture appeared to have few or no side effects, although two people complained that the needles were painful. “Clearly, many millions of Chinese get acupuncture without any major problems so I think this is really a minor point,” Flachskampf observed.
[Circulation 2007; DOI: 10.1161/CIRCULATIONAHA.106.661140. Flachskampf FA, Gallasch J, Gefeller O, et al. "Randomized trial of acupuncture to lower blood pressure." ]
acupunctureDan shen can reduce blood pressure, study says
APS.org - Many patients with high blood pressure have sought relief from complementary and alternative medicine (CAM). In so doing, many have consumed danshen, a Chinese herb used in Oriental medicine that promotes blood flow and treats cardiovascular disease.
Tanshinone IIA, an antioxidant in salviae miltiorrhizae (Dan shen 丹参). Since tanshinone IIA is widely available, a team of researchers has used it to investigate if this active ingredient can reduce blood pressure. In a soon-to-be-released study, using an animal model, the scientists have found that tanshinone IIA does reduce blood pressure.
Summary of Methodology
To assess the effect of tanshinone IIA, the protocol consisted of several parts. The researchers applied the 2-kidney-1-clip protocol to induce renal hypertension in male golden Syrian hamsters. The animals were anesthetized and a retroperitoneal approach was used to place a silver clip to constrict the right renal artery. Sham-operated hamsters and mice underwent the same procedure, except for the placement of a clip.
Both sets of hamsters received 50 μg of tanshinone IIA/100g of body weight once a day for two weeks. After the two-week treatment period, mean arterial blood pressure was measured in the right carotid artery. To examine the microvascular actions of tanshinone IIA researchers applied it topically to the hamsters’ cheek pouch or mice cremaster muscles to achieve the final concentration of one μg/ml or five μg/ml. After the application of tanshinone IIA, the experiment was continued for an additional 60-minute period in order to measure arteriolar diameter and peri-arteriolar nitric oxide concentration.
Results
Tanshinone IIA was found to have significantly reduced blood pressure in the hamsters. The experimental constriction of the renal artery increased mean arterial pressure to 161.2±6.9 mmHg relative to 114.3±9.2 mmHg in age-matched hamsters. Treatment with 50 μg tanshinone IIA/100g body for two weeks reduced the mean arterial pressure from 161.2±6.9 to 130.0±7.8 mmHg.
The research team also discovered that tanshinone IIA caused widening of the arterioles in the hamster cheek pouch microcirculation via enhanced expression of endothelial nitric oxide synthase. The topical application of tanshinone IIA at one μg/ml and five μg/ml caused significant dose-related vasodilation, indicated by the increased agent/control ratio of arteriolar diameters from 1.0 to 1.25±0.08 and 1.57±0.11, respectively, in the hamster cheek pouch. The increase in arteriolar diameter ratio was significant relative to the vehicle for each concentration as well as for comparison between the two concentrations of tanshinone IIA.
Conclusions
As a result of the findings the researchers concluded that tanshinone IIA: (1) significantly reduced blood pressure in hamsters, (2) enhanced the expression of endothelial nitric oxide synthase, (3) increased the production of nitric oxide and (4) induced blood pressure changes through vasodilation in hamster blood microvessels. While the mechanisms of how tanshinone IIA or danshen work in hypertension are not yet fully understood, these results contribute to the effort to bring complementary and alternative medicine and allopathic care closer together in the treatment of hypertensive patients.
The study will soon be published in the American Journal of Physiology – Heart and Circulatory Physiology (December 15, 2006), doi:10.1152/ajpheart.01027.2006, and is entitled Endothelial Nitric Oxide Synthase is a Molecular Vascular Target for the Chinese Herb Danshen in Hypertension. It was conducted by the team of David D. Kim, PhD, OMD; Fabiola A. Sánchez, PhD; Ricardo G. Durán, BS; Takehito Kanetaka, MD; and Walter N. Durán, PhD, all of the Program in Vascular Biology, Department of Pharmacology and Physiology and Department of Surgery, UMDNJ-New Jersey Medical School, Newark, NJ.
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