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Title
Growth hormone and glutamine do not stimulate intestinal adaptation
following massive
small bowel resection in the rat.
Author
Vanderhoof JA; Kollman KA; Griffin S; Adrian TE
Source
J Pediatr Gastroenterol Nutr, 1997 Sep, 25:3, 327-31
Abstract
BACKGROUND: Certain nutrients and other trophic factors are highly
sensitive stimulants
of intestinal adaptation following short bowel syndrome. Growth
hormone and glutamine in
a modified diet have been shown to enhance nutrient absorption
in patients with severe short
bowel syndrome. However, neither growth hormone nor glutamine
is capable of enhancing
adaptation in an animal model. This study was conducted to determine
if the combination of
glutamine and growth hormone could enhance gut adaptation following
massive small
bowel resection in the rat. METHODS: Thirty-four male rats received
70% jejunoileal
resection. The first group received glycine and rat growth hormone,
the second glutamine
and rat growth hormone, and the third glycine but no growth hormone.
RESULTS: There
was no evidence that the combination of glutamine and growth
hormone could enhance
mucosal mass, mucosal protein, or mucosal DNA levels relative
to the other two control
groups of animals. Likewise, sucrase activities were not enhanced
by glutamine and growth
hormone. CONCLUSIONS: It is unlikely that the combination of
glutamine and growth
hormone will be of benefit in the treatment of patients with
short bowel syndrome. The
results in previous human studies can be alternatively explained
by the long-term
nonspecific effect of enteral nutrition on gut adaptation.
Title
Nutrient metabolism by gut tissues.
Author
Britton R; Krehbiel C
Source
J Dairy Sci, 1993 Jul, 76:7, 2125-31
Abstract
The gut uses a disproportionate amount of energy (about 25% of
total oxygen consumption)
for the size of the tissue (about 6% of body weight). Therefore,
knowledge of metabolites
used in gut tissues is important to assess nutrient needs. The
VFA produced intraruminally
are used to varying degrees by rumen epithelial tissue. A review
of net portal absorption
data essentially confirms earlier studies that show acetate,
propionate, and butyrate
metabolism by stomach tissue to be 30, 50, and 90%, respectively,
of ruminant production.
Glucose also is used by rumen epithelial tissue; however, glutamine
appears to be a poor
substrate for energy production. Tissue of the small intestine
uses glutamine, glucose, and
ketones but does not use VFA very well for energy. Cecal and
colonic tissues can use
glucose and glutamine for energy, but butyrate is the preferred
substrate in both tissues.
Title
Glutamine-enriched enteral diet enhances bacterial clearance
in protected bacterial peritonitis,
regardless of glutamine form [see comments]
Author
Furukawa S; Saito H; Inaba T; Lin MT; Inoue T; Naka S; Fukatsu
K; Hashiguchi Y; Han I;
Matsuda T; Ikeda S; Muto T
Source
JPEN J Parenter Enteral Nutr, 1997 Jul, 21:4, 208-14
Abstract
BACKGROUND: The effects of glutamine (Gln)-enriched enteral diets
on bacterial
clearance were investigated in a rat protracted peritonitis model.
The effects of the Gln form,
peptide-based vs free amino acid-based, were also compared. METHODS:
Twenty-three
rats underwent gastrostomy. An osmotic pump was implanted in
the peritoneal cavity. The
rats received a continuous intragastric infusion of one of three
diets: Gln-depleted (Gln 0),
Gln-enriched with the Gln in free amino acid form (Gln F), or
Gln-enriched with the Gln in
oligopeptide form (Gln P). The three formulas were isocaloric
and isonitrogenous. The
pumps delivered a continuous infusion of Escherichia coli, starting
at 48 hours after
implantation, for 24 hours. Then, the animals were killed. RESULTS:
Bacterial numbers in
peritoneal lavaged fluid (PLF) and the liver were significantly
lower in the Gln P and Gln F
groups than in the Gln 0 group. The bacterial number in PLF correlated
with that in the liver.
Neither the number nor the population of peritoneal exudative
cells differed among groups.
Plasma levels of proline, alanine and citrulline were significantly
higher in the Gln P and
Gln F groups than in the Gln 0 group. Both Gln supplemented groups
showed significantly
greater villous height, crypt depth, and numbers of mitoses per
crypt in the small intestine
than the Gln 0 group. CONCLUSIONS: Supplemental Gln enhances
peritoneal and hepatic
bacterial clearance, regardless of Gln form. Gln-enriched may
be more beneficial than
Gln-depleted enteral diets in peritonitis.
Title
Intravenous glutamine fails to improve gut morphology after radiation
injury.
Author
Scott TE; Moellman JR
Source
JPEN J Parenter Enteral Nutr, 1992 Sep, 16:5, 440-4
Abstract
Male Sprague-Dawley rats housed in individual metabolic cages
received total parenteral
nutrients via chronic indwelling internal jugular catheters to
determine whether
supplementing parenteral nutrition with glutamine would accelerate
recovery of small-bowel
morphology after abdominal radiation. After recovering from catheter
insertion for 3 days
they received either 1000 cGy gamma radiation to the abdomen
only or no radiation and
immediately thereafter received isonitrogenous and isocaloric
intravenous solutions
containing either 0% or 2% glutamine at 1.58 mL/h for the next
5 days. Intestinal segments
were then assayed for whole-bowel deoxyribose nucleic acid content
and villus height.
Irradiation caused a 40% decrement in these parameters, which
were not restored by
glutamine supplementation. Therefore, intravenous glutamine supplementation
failed to
accelerate recovery of small-bowel morphology in this model of
combined surgical and
radiation injury.
Title
The role of glutamine in maintaining a healthy gut and supporting
the metabolic response to
injury and infection.
Author
Souba WW; Klimberg VS; Plumley DA; Salloum RM; Flynn TC; Bland
KI; Copeland
EM 3d
Source
J Surg Res, 1990 Apr, 48:4, 383-91
Abstract
In the critically ill surgical patient a variety of therapeutic
maneuvers is required to maintain
a "healthy gut." Provision of adequate amounts of glutamine
to the gastrointestinal mucosa
appears to be just one of these maneuvers. Other methods utilized
to protect the gut from
becoming a wound include: (a) minimizing additional systemic
insults (such as
hypotension, sepsis, multiple operative procedures); (b) aggressive
pulmonary care; (c) the
judicious use of antibiotics; and (d) aggressive enteral or parenteral
feedings. The concept
that the gut is an organ of quiescence following surgical stress
merits reconsideration. The
intestinal tract plays a central role in interorgan glutamine
metabolism and is a key regulator
of nitrogen handling following surgical stress. Critically ill
patients are susceptible to
developing gut-origin sepsis, the incidence of which will be
diminished by instituting
measures and providing treatments which support intestinal structure,
function, and
metabolism. Provision of glutamine-enriched diets to such patients
may be one of these
therapies.
Title
Glutamine.
Author
Hall JC; Heel K; McCauley R
Source
Br J Surg, 1996 Mar, 83:3, 305-12
Abstract
Glutamine is the most abundant free amino acid in the circulation.
It is a primary fuel for
rapidly dividing cells and plays a key role in the transport
of nitrogen between organs.
Although glutamine is absent from conventional regimens aimed
at nutritional support,
glutamine deficiency can occur during periods of metabolic stress;
this has led to the
reclassification of glutamine as a conditionally essential amino
acid. Experiments with
various animal models have demonstrated that the provision of
glutamine can result in better
nitrogen homoeostasis, with conservation of skeletal muscle.
There is also considerable
evidence that glutamine can enhance the barrier function of the
gut. This review concludes
by discussing the clinical evidence that supports the inclusion
of stable forms of glutamine
in solutions of nutrients.
Title
Intestinal fuels: glutamine, short-chain fatty acids, and dietary
fiber [see comments]
Author
Evans MA; Shronts EP
Source
J Am Diet Assoc, 1992 Oct, 92:10, 1239-46, 1249
Abstract
In recent years, considerable research has focused on the physiologic
effects and clinical
uses of three dietary constituents thought to be trophic to the
intestinal tract in human beings:
glutamine, short-chain fatty acids (SCFAs), and dietary fiber.
Glutamine is an important
nitrogen-carrying amino acid that may be "conditionally
essential" in certain disease states to
support the gut barrier and immune function and overall protein
use. Colonic irrigations
with SCFA preparations have demonstrated enhanced healing of
bowel tissue in animals
and human beings. Dietary fiber supports bacterial SCFA production,
normal stool output,
and the gut barrier and immune function. However, optimal fiber
doses for various medical
conditions are not known, and the risk for gastrointestinal (GI)
obstruction, diarrhea, gas,
and bloating necessitates careful selection of patients and daily
monitoring of fiber tolerance.
A review of the current literature indicates that widespread
use of glutamine and SCFA
additives parenterally and enterally awaits further evidence
of safety and efficacy in human
beings, establishment of appropriate doses, and advances in formulation
technology.
Administration of dietary fiber to enhance bowel motility should
be considered in long-term
tube-fed patients with intact GI function and sufficient fluid
tolerance to permit hydration of
fiber. Industrywide agreement on fiber analysis methods and labeling
standards (eg, fiber
fermentability vs solubility) would facilitate selection of enteral
products. To streamline
studies and optimize research efforts in future clinical trials,
standard criteria for evaluating
GI function, diarrheagenic factors, and intestinal outcome variables
should be established.
Title
The effect of glutamine-enriched TPN on gut immune cellularity.
Author
Alverdy JA; Aoys E; Weiss Carrington P; Burke DA
Source
J Surg Res, 1992 Jan, 52:1, 34-8
Abstract
Prolonged parenteral feeding with standard nutrient solutions
results in significant alteration
in the structural, hormonal, and immunological composition of
the intestinal tract. The
purpose of the following study was to evaluate the effect of
glutamine-supplemented
parenteral nutrition on the immune cellularity of the gut. Twenty-one
Fischer rats were
randomized to three groups of seven animals each. Group I was
fed rat chow and water ad
lib, Group II was fed a standard solution of total parenteral
nutrition (TPN) (D25/4.25%
amino acids) via a central venous catheter, and Group III was
fed the standard solution of
TPN with 2% glutamine which was isonitrogenous and isocaloric
to Group II. Animals
were fed their respective diets for 1 week and bile was collected
and assayed for secretory
IgA (s-IgA) and IgM. The terminal ileum was stained and assayed
for IgA+, IgM+, IgG+,
CD4+, and CD8+ plasma cells and lymphocytes. Results indicate
that the feeding of a
standard parenteral diet results in a significant decrease in
biliary s-IgA and IgA+ plasma
cells in the gut lamina propria compared to chow-fed animals
(S-IgA: chow, 858 +/- 23
micrograms/ml; TPN, 494 +/- 41 micrograms/ml; IgA cells: chow,
35.7 +/- 1.8; TPN, 8.6
+/- 0.9 cells/hpf). In addition a marked depletion of CD4+ and
CD8+ lymphocytes was
observed with standard solutions of parenteral nutrition compared
to chow (CD4+: chow,
36.8 +/- 6.6; TPN, 14.9 +/- 6.0; CD8+: chow, 18.8 +/- 5.6; TPN,
5.7 +/- 2.7 cells/hpf). The
addition of glutamine to the standard TPN solution maintained
both B and T cell populations
at levels similar to chow-fed animals.(Abstract TRUNCATED
AT 250 WORDS)
Title
Glutamine and cancer.
Author
Souba WW
Source
Ann Surg, 1993 Dec, 218:6, 715-28
Abstract
OBJECTIVE: This overview on glutamine and cancer discusses the
importance of
glutamine for tumor growth, summarizes the alterations in interorgan
glutamine metabolism
that develop in the tumor-bearing host, and reviews the potential
benefits of glutamine
nutrition in the patient with cancer. SUMMARY BACKGROUND DATA:
Glutamine is
the most abundant amino acid in the blood and tissues. It is
essential for tumor growth and
marked changes in organ glutamine metabolism are characteristic
of the host with cancer.
Because host glutamine depletion has adverse effects, it is important
to study the regulation
of glutamine metabolism in cancer and to evaluate the impact
of glutamine nutrition in the
tumor-bearing state. METHODS: Data from a variety of investigations
on glutamine
metabolism and nutrition related to the host with cancer were
compiled and summarized.
RESULTS: Numerous studies on glutamine metabolism in cancer indicate
that many
tumors are avid glutamine consumers in vivo and in vitro. As
a consequence of progressive
tumor growth, host glutamine depletion develops and becomes a
hallmark. This glutamine
depletion occurs in part because the tumor behaves as a "glutamine
trap" but also because of
cytokine-mediated alterations in glutamine metabolism in host
tissues. Animal and human
studies that have investigated the use of glutamine-supplemented
nutrition in the host with
cancer suggest that pharmacologic doses of dietary glutamine
may be beneficial.
CONCLUSIONS: Understanding the control of glutamine metabolism
in the tumor-bearing
host not only improves the knowledge of metabolic regulation
in the patient with cancer but
also will lead to improved nutritional support regimens targeted
to benefit the host.
Title
Role of glutamine in bacterial transcytosis and epithelial cell
injury.
Author
Panigrahi P; Gewolb IH; Bamford P; Horvath K
Source
JPEN J Parenter Enteral Nutr, 1997 Mar, 21:2, 75-80
Abstract
BACKGROUND: L-Glutamine is the principal energy source for small
intestinal
enterocytes. Diminution of intestinal function, mucosal atrophy,
and increased bacterial
translocation have been noted during total parenteral nutrition
(TPN). In a rat model of
glutamine starvation, we previously showed that luminal glutamine
is essential for optimal
intestinal function. In this study, we examined the effect of
apical vs basolateral glutamine
on bacterial translocation in a Caco-2 cell culture system and
bacteria-induced tissue injury
in a weanling rabbit ileal loop model. METHODS: Caco-2 cells
were grown in a transwell
system. After confluence, apical and basolateral chambers received
defined media, and
glutamine deprivation was carried out over a 4- to 48-hour period.
Escherichia coli
transcytosis and structure/function studies were then performed.
In a second series of
experiments, the effect of intraluminal glutamine supplementation
was evaluated in an E.
coli-induced tissue injury model in weanling rabbit ileal loops.
RESULTS: Expression of
disaccharidases, glucoamylase, and Na+/K(+)-adenosine 5'-triphosphatase
(ATPase) were
significantly reduced when cells were deprived of glutamine from
the apical side, and there
was increased bacterial translocation across the monolayer. Transepithelial
epithelial
resistance (TEER) across the monolayer was also reduced in the
glutamine-free cultures.
Glutamine replenishment over 24 to 48 hours restored the original
functions. Basolateral
deprivation had a smaller effect on the Caco-2 cells. Typical
necrotic mucosal injury caused
by E. coli in the ileal loops was blocked by co-infiltration
of the loops with glutamine.
CONCLUSIONS: This study demonstrates for the first time that
the supply of glutamine
from the apical side is of critical importance for maintaining
optimal structure and function
of the enterocytes. The effects are not acute or energy related.
These observations have
important clinical implications in the management of patients
under critical care, including
premature infants and patients receiving TPN, for whom lack of
glutamine from the luminal
side could produce mucosal dysfunction, resulting ultimately
in severe atrophic/necrotic
complications. |
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