Chemical embolization of artery to the fundus reduced ghrelin substantially
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New minimally invasive method tested in pigs yields result as good as
bariatric surgery
Johns Hopkins scientists report success in significantly suppressing
levels of the "hunger hormone" ghrelin in pigs using a minimally
invasive means of chemically vaporizing the main vessel carrying blood
to the top section, or fundus, of the stomach. An estimated 90 percent
of the body's ghrelin originates in the fundus, which can't make the
hormone without a good blood supply.
"With gastric artery chemical embolization, called GACE, there's no
major surgery," says Aravind Arepally, M.D., clinical director of the
Center for Bioengineering Innovation and Design and associate
professor of radiology and surgery at the John Hopkins University
School of Medicine. "In our study in pigs, this procedure produced an
effect similar to bariatric surgery by suppressing ghrelin levels and
subsequently lowering appetite."
Reporting on the research in the September 16 online edition of
Radiology, Arepally and his team note that for more than a decade,
efforts to safely and easily suppress grehlin have met with very
limited success.
Bariatric surgery - involving the removal, reconstruction or bypass of
part of the stomach or bowel - is effective in suppressing appetite
and leading to significant weight loss, but carries substantial
surgical risks and complications. "Obesity is the biggest biomedical
problem in the country, and a minimally invasive alternative would
make an enormous difference in choices and outcomes for obese people,"
Arepally says.
Arepally and colleagues conducted their study over the course of four
weeks using 10 healthy, growing pigs; after an overnight fast, the
animals were weighed and blood samples were taken to measure baseline
ghrelin levels. Pigs were the best option, he says, because of their
human-like anatomy and physiology.
Using X-ray for guidance, members of the research team threaded a thin
tube up through a large blood vessel near the pigs' groins and then
into the gastric arteries supplying blood to the stomachs. There, they
administered one-time injections of saline in the left gastric
arteries of five control pigs, and in the other five, one-time
injections of sodium morrhuate, a chemical that destroys the blood
vessels.
The team then sampled the pigs' blood for one month to monitor ghrelin
values. The levels of the hormone in GACE-treated pigs were suppressed
up to 60 percent from baseline.
"Appetite is complicated because it involves both the mind and body,"
Arepally says. "Ghrelin fluctuates throughout the day, responding to
all kinds of emotional and physiological scenarios. But even if the
brain says "produce more ghrelin," GACE physically prevents the
stomach from making the hunger hormone."
###
The research was funded by the National Institutes of Health.
Authors on the paper are Brad P. Barnett, Tarek T. Patel, Valerie
Howland, Racy C. Boston, Dara L. Kraitchman, Ashkan A. Malayeri, and
Arepally, all of Hopkins.
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consumption though, is affected by other factors so reduction of
fundus function as done in the study above has a potential to help in
restricting caloric intake.
Arbor
Exp Biol Med (Maywood). 2007 Dec;232(11):1449-57.
Fundectomy-evoked osteopenia in pigs is mediated by the gastric-
hypothalamic-pituitary axis.
Tatara MR, Krupski W, Sliwa E, Maciejewski R, Dabrowski A.
Department of Animal Physiology, Faculty of Veterinary Medicine, The
Agricultural University of Lublin, ul. Akademicka 12, 20-950 Lublin,
Poland. mat...@o2.pl
The aim of the study was to determine the effects of gastric
impairment in pigs on the axial and peripheral skeletal system
properties and to test the hypothesis that fundectomy-evoked
osteopenia is related to disturbed gastric-hypothalamic-pituitary axis
function. Forty-day-old male piglets were subjected to experimental
fundectomy (FX group, n = 6) to induce osteopenia, while sham
operation was performed in the controls (SHO group, n = 6). At the age
of 8 months, serum samples were collected, and the animals were
sacrificed to obtain lumbar vertebrae (L1-L6) and right humerus for
analysis. Using quantitative computed tomography (QCT) and dual-energy
x-ray absorptiometry (DEXA) methods, bone mineral density and bone
mineral content of the vertebrae and humerus were measured. The
compression and three-point bending tests were applied to determine
mechanical properties of lumbar vertebrae and humerus, respectively.
Furthermore, geometric properties of humerus were assessed. Serum
concentrations of ghrelin, growth hormone (GH), insulin-like growth
factor-1 (IGF-1), and selected macro- and microelements were also
determined. Performed fundectomy decreased body weight in pigs by 66%
compared with pair-fed sham operated pigs (P < 0.0001). Bone weight,
bone mineral density, and bone mineral content of the lumbar vertebrae
and humerus were significantly decreased in the fundectomized pigs (P
< 0.01). Mechanical parameters of the lumbar spine and humerus were
decreased after the fundectomy, as well. Serum concentrations of
ghrelin, GH, and IGF-1 were lowered by 74.4%, 90.6%, and 54.6% in the
fundectomized pigs, respectively (all P < 0.001). Moreover, the serum
concentrations of calcium, magnesium, iron and copper in the
fundectomized animals were significantly decreased by 15.5%, 45.3%,
26.7%, and 26.2%, respectively (P <or= 0.05). In conclusion, the
results obtained showed that both the disturbed gastric-hypothalamic-
pituitary axis function and impaired mineral metabolism are associated
with development of postfundectomy osteopenia of axial and peripheral
skeleton in pigs.
PMID: 18040069 [PubMed - indexed for MEDLINE]