Dr. Ron’s Research Review – February 16, 2010

© 2010

 

This week’s research review has:

An article on melatonin as an inhibitor of aromatase promoter expression,

A study that showed sesame seeds increased serum sex hormone-binding globulin and urinary 2-hydroxyestrone (n = 8) significantly by 15 and 72%, respectively.

A review article on “The clinical significance of gastrointestinal changes with aging” that includes achlorhyrdria and vitamin D malabsorption.

 

Here’s a link to the article on Vitamin D dosing by Joseph Pizzorno that Dr. Wright mentioned in last week’s clinic meeting.

 

Dr. Ron

 

Abstracts

Melatonin inhibits aromatase promoter expression by regulating cyclooxygenases expression and activity in breast cancer cells

            (Martinez-Campa, Gonzalez et al. 2009) Download           

BACKGROUND: Melatonin reduces the development of breast cancer interfering with oestrogen-signalling pathways, and also inhibits aromatase activity and expression. Our objective was to study the promoters through which melatonin modifies aromatase expression, evaluate the ability of melatonin to regulate cyclooxygenases and assess whether the effects of melatonin are related to its effects on intracellular cAMP, in MCF-7 cells. METHODS: Total aromatase mRNA, aromatase mRNA promoter regions and cyclooxygenases mRNA expression were determined by real-time RT-PCR. PGE(2) and cAMP were measured by kits. RESULTS: Melatonin downregulated the gene expression of the two major specific aromatase promoter regions, pII and pI.3, and also that of the aromatase promoter region pI.4. Melatonin 1 nM was able to counteract the stimulatory effect of tetradecanoyl phorbol acetate on PGE(2) production and inhibit COX-2 and COX-1 mRNA expression. Melatonin 1 nM elicited a parallel time-dependent decrease in both cyclic AMP formation and aromatase mRNA expression. CONCLUSIONS: This study shows that melatonin inhibits aromatase activity and expression by regulating the gene expression of specific aromatase promoter regions. A possible mechanism for these effects would be the regulation by melatonin of intracellular cAMP levels, mediated by an inhibition of cyclooxygenase activity and expression.

 

Sesame ingestion affects sex hormones, antioxidant status, and blood lipids in postmenopausal women

            (Wu, Kang et al. 2006) Download

Sesame ingestion has been shown to improve blood lipids in humans and antioxidative ability in animals. Sesamin, a sesame lignan, was recently reported to be converted by intestinal microflora to enterolactone, a compound with estrogenic activity and also an enterometabolite of flaxseed lignans, which are known to be phytoestrogens. Whether sesame can be a source of phytoestrogens is unknown. This study was designed to investigate the effect of sesame ingestion on blood sex hormones, lipids, tocopherol, and ex vivo LDL oxidation in postmenopausal women. Twenty-six healthy subjects attended, and 24 completed, this randomized, placebo-controlled, crossover study. Half of them consumed 50 g sesame seed powder daily for 5 wk, followed by a 3-wk washout period, then a 5-wk 50-g rice powder placebo period. The other half received the 2 supplements in reverse order. After sesame treatment, plasma total cholesterol (TC), LDL-C, the ratio of LDL-C to HDL-C, thiobarbituric acid reactive substances in oxidized LDL, and serum dehydroepiandrosterone sulfate decreased significantly by 5, 10, 6, 23, and 18%, respectively. The ratio of alpha- and gamma-tocopherol to TC increased significantly by 18 and 73%, respectively. All of these variables differed significantly between the 2 treatments. Serum sex hormone-binding globulin and urinary 2-hydroxyestrone (n = 8) increased significantly by 15 and 72%, respectively, after sesame treatment, and these concentrations tended to differ (P = 0.065 and P = 0.090, respectively) from those after the placebo treatment. These results suggest that sesame ingestion benefits postmenopausal women by improving blood lipids, antioxidant status, and possibly sex hormone status.

 

The clinical significance of gastrointestinal changes with aging

            (Bhutto and Morley 2008) Download

PURPOSE OF REVIEW: With the graying of the world's population, there is an increased interest in the physiological effects of aging. This review examines the physiological changes of the gut with aging and their clinical significance. RECENT FINDINGS: Changes with aging in the gastrointestinal tract are variable, but in some cases they are responsible for a variety of symptoms. Thus, alterations in taste and smell, gastric motility, intestinal overgrowth and changes in gastrointestinal hormone release are the basis of the physiological anorexia of aging. Alterations in swallowing lead to silent aspiration. Changes in gastric emptying play a role in postprandial hypotension. Changes in gastrointestinal function can lead to constipation and fecal incontinence. Weakening of the colonic muscular wall produces diverticula. Achlorhydria is associated with malabsorption of some forms of iron and calcium. Vitamin D malabsorption aggravates the hypovitaminosis D that is so common in older persons. Changes in probiotics can lead to diarrhea and altered immune system. In the liver, aging is associated with delayed drug metabolism. SUMMARY: Changes in the physiology of the gut play a role in the anorexia of aging, aspiration pneumonia, postprandial hypotension, constipation and fecal incontinence.

References

Bhutto, A. and J. E. Morley (2008). "The clinical significance of gastrointestinal changes with aging." Curr Opin Clin Nutr Metab Care 11(5): 651-60.

Martinez-Campa, C., A. Gonzalez, et al. (2009). "Melatonin inhibits aromatase promoter expression by regulating cyclooxygenases expression and activity in breast cancer cells." Br J Cancer 101(9): 1613-9.

Wu, W. H., Y. P. Kang, et al. (2006). "Sesame ingestion affects sex hormones, antioxidant status, and blood lipids in postmenopausal women." J Nutr 136(5): 1270-5.