Does Menopause Affect Outcomes from Roux-en-Y Gastric Bypass Surgery?

Estradiol increases body weight loss and satiation effects of Roux-en-Y gastric bypass (RYGB) in ovariectomized rats, according to the August issue of Gastroenterology.

Approximately ~85% of bariatric surgery procedures are performed on women, but little is known about the effects of menopause or reproductive hormones, such as estrogen, on outcomes.

Lori Asarian et al. performed RYGB surgeries on female rats that had been fattened for 3 weeks on a high-energy diet and then had their ovaries removed, to model menopause. The rats were then placed on varying diets and some were given physiologic amounts of estradiol (a form of estrogen).

The authors found that the estradiol significantly increased the ability of RYGB to reduce food intake and body weight gain, independently of what type of diet the rats were offered after the surgery (see figure).

Body weight (top) and food intake (bottom) following RYGB or a sham operation in ovariectomized rats given estradiol (E2) or oil (as a control). Significant differences were observed in SHAM-OIL vs RYGB-OIL (#); RYGB-OIL vs RYGB-E2 (*); and SHAM-OIL vs SHAM-E2 (+).

They also provided evidence that estrogen increased the satiating effects of the intestinal hormones glucagon-like peptide 1 (GLP-1, which stimulates insulin secretion and makes people feel full) and cholecystokinin (which causes release of digestive enzymes and suppresses hunger).

Asarian et al. concluded that RYGB surgery might be more effective for healthy pre-menopausal women (or post-menopausal women who receive hormone replacement therapy) than women with lower levels of estrogen.

It is not clear whether estrogens promote the effects of RYGB by the same mechanisms by which they contribute to the normal control of eating and body weight. Further experiments are also needed to determine whether estrogens affect outcomes from other types of bariatric surgeries, such as gastric banding or gastric sleeve resection.

Read the article online.
Asarian L, Abegg K, Geary N, et al. Estradiol increases body weight loss and gut-peptide satiation after roux-en-y gastric bypass in ovariectomized rats. Gastroenterology 2012;143:325–327.e2.