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Department of Pathology, University of Cincinnati Medical Center, Cincinnati, OH 45267 and
*
Analytical Research Services and
Strategic Discovery Research and Development, Ross Products Division, Abbott Laboratories, Columbus, OH 43215
2To whom correspondence should be addressed. E-mail: tsopp{at}email.uc.edu.
 |
ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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-tocopherol and 3H-retinol through the
gastric tube followed by an infusion of PBS at 3 mL/h for 8 h.
Lymph was collected hourly for 8 h. Under steady-state
conditions, the amount of 14C--tocopherol and
3H-retinol transported into lymph was significantly higher
in the STG-fed rats compared with those fed PM in both control and
I/R groups. In addition, control and I/R rats given STG had earlier
steady-state outputs of 14C--tocopherol and
3H-retinol and maintained 
30% higher outputs in lymph
throughout the 8-h lymph collection period compared with rats given the
PM. We conclude that STG provides the opportunity to potentiate
improved absorption of fat-soluble vitamins under normal and
malabsorptive states.
KEY WORDS: • lymph • structured triglycerides • fat-soluble vitamins • malabsorption • enteral nutrition • rats
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Numerous investigations have demonstrated that STG have different
metabolic actions than identical PM of oils that have not been
interesterified. For example, a collection of studies in various animal
models of burn injury, endotoxic shock and trauma demonstrates that
diets containing STG as the primary source of fat may reduce the
catabolic response to injury compared with conventional fats or with PM
of oils similar in fatty acid composition to the STG
(1
2
3
4
5
6)
. A similar body of knowledge shows the advantages
of enterally fed STG vs. PM in relation to differences in absorption,
chylomicron formation and lymphatic transport of triglycerides.
Enhanced absorption of linoleic acid [18:2(n-6)] has been observed in
cystic fibrosis patients who were fed STG containing LCFA and MCFA
(7
,8)
. Jensen et al. (9)
reported that in
lymph-cannulated dogs administered oils similar to those used in
this study, lymphatic absorption of MCFA from STG was 2.6-fold higher
(10:0 in excess of 8:0) compared with its equivalent PM. Molecular
species analyses revealed that the MCFA in lymph were present on the
same glycerol backbone as LCFA. In a lymph fistula rat model, we
assessed the intestinal absorption of STG containing two MCFA (8:0) and
one LCFA [18:2(n-6)] (10)
. The chain length of the fatty
acid on the STG molecule affected the digestion, absorption and
lymphatic transport of the triglyceride. Animal and clinical studies
conducted over the past 7 y have broadened our knowledge of the
absorption and lymphatic transport benefits of STG vs. their PM under
conditions of malabsorption. For instance, rat absorption studies by
Christensen et al. (11
12
13)
and Jensen et al.
(14)
have shown that defined triglycerides with specific
fatty acids in the sn-2 position on the glycerol backbone
may provide increased absorption of essential fatty acids (EFA) in
syndromes that reduce pancreatic lipase and/or compromise bile
production. Recently, Kenler et al. (15)
showed that
postsurgical abdominal cancer patients who were fed STG (fish oil/MCT)
vs. a control diet reported experiencing 40% fewer days of
gastrointestinal complications, and that there was a 50% decline in
the number of cases of gastrointestinal complications reported.
Recently we demonstrated that the digestion, absorption and lymphatic
transport of lipid and key EFA from STG were significantly higher
compared with an equivalent PM in a normal lymph fistula rat model and
in a rat model of lipid malabsorption caused by ischemia/repurfusion
(I/R) injury (16)
. This model of lipid malabsorption was
validated extensively in a previous report by Fujimoto et al.
(17)
, who demonstrated that intestinal lipid absorption is
suppressed by I/R and thus provides a good index of the intestinal
mucosa function. Recovery of intestinal mucosal function is associated
with full restoration of intestinal lipid absorption. The goals of this
study were to explore further the potential absorptive benefits of STG
in malabsorptive conditions. Because the absorption of lipophilic
compounds such as fat-soluble vitamins is impaired in diseases that
cause fat malabsorption (Crohn’s disease, short-bowel syndrome,
cystic fibrosis), we compared for the first time the intestinal
absorption and lymphatic transport of tocopherol and retinol when
delivered gastrically with either STG or its equivalent PM under normal
conditions and after I/R injury to the small bowel.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Adult male Sprague-Dawley rats (Harlan, Indianapolis, IN) weighing 300–350 g were used for the study. Upon arrival, they were housed in quarantine for 1 wk and fed a nonpurified diet (LM485, Harlan Tekland, Madison, WI). The light in the room was regulated to give a cycle of 12 h light and 12 h dark.
Lymph-fistula rat model and ischemic injury.
Approval of this study was granted by the Animal Care Committee of the University of Cincinnati in accordance with guidelines set forth in the National Institutes of Health Guide for the Care and Use of Laboratory Animals.
Rats were deprived of food overnight before surgical procedures. Under
halothane anesthesia, a laparotomy was performed. Ischemic injury to
the small bowel was produced by occluding the superior mesenteric
artery (SMA) for 20 min with a microbulldog clamp (16
,17)
.
At the end of the ischemic period, the clamp was released and
three drops of lidocaine were applied directly on the SMA to ensure
perfusion. In the control (sham) rats, the SMA was isolated and
manipulated in a similar fashion, but was not occluded. In both groups,
the intestinal lymph duct was cannulated according to the method of
Bollman et al. (18)
. In addition, a soft silicone gastric
tube (1.6 mm o.d.) was inserted into the fundus of the stomach. The
tubing was secured with a purse-string suture. Buprenorphine (1
mg/kg) was given to each rat during surgery to alleviate pain.
Postoperatively, the rats were infused intragastrically at a rate of 3
mL/h with a 50 g/L glucose-saline solution containing 145 mmol/L
NaCl, 4 mmol/L KCl and 0.28 mol/L glucose. The rats were allowed to
recover for at least 24 h in restraining cages maintained at a
temperature of 30°C before lipid infusion.
Experimental plan and procedures.
Four groups of rats were studied as follows: two groups of
sham-operated controls and two groups with small bowel I/R injury
(n = 6–8/group). The morning after surgery, rats
were fed by gastric tube 1 mL of either the fish oil/MCT STG or the PM.
The two groups of sham-operated controls randomly received either 1
mL of fish oil/MCT STG or its PM equivalent (Fig. 1
). Infused with the oil was 35.7 mg of -tocopherol (labeled with 1
µCi of [5-methyl 14C]-tocopherol) and 0.15
mg of retinol (labeled with 10 µCi of [11,
12-3H(N)] retinol). Both the
-tocopherol and retinol were purchased from Sigma Chemical, St.
Louis, MO. The radioactive [11,12-3H(N)]
retinol and [5-methyl 14C]-tocopherol were
obtained from New England Nuclear Products, Boston, MA.
|
.
The positional distribution of the fatty acids at the sn-1,
-2, and -3 positions on the triglyceride molecule is, therefore,
random. The PM was prepared by mixing the same weight proportions of
fish oil and MCT as in the STG without interesterification. The fatty
acid compositions of the starting oils, STG, and PM are outlined in
Table 1
. The 2-monoglyceride fatty acid compositions (method described below)
of the fish oil/MCT STG and the PM are shown in Table 2
. Similarly, 1 mL of either STG or PM with -tocopherol and retinol
was given by gavage in rats with or without injury caused by I/R.
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, and
aliquots of the extract were taken for determination of both
14C--tocopherol and
3H-retinol. Radioactivity was measured in an
aqueous miscible scintillant (Poly-Fluor, Packard Instrument, Downers
Grove, IL). The samples were counted for 10 min in a liquid
scintillation spectrometer (LKB model 1209 Rackbeta, Bromma,
Sweden). Samples were corrected for quenching in reference to a
series of 14C- and
3H-labeled standards that had been progressively
quenched. Analysis of triglyceride molecular species.
The separation, identification and quantitation of the triglyceride
molecular species of STG and PM using either supercritical fluid
chromatography or high temperature gas chromatography were performed as
previously described (21)
. Triglyceride species were
separated according to their equivalent carbon number (ECN), defined as
the sum of the total carbon number in the acyl side chains of the
triglyceride molecule. A known amount of the STG or PM was dissolved in
chloroform/methanol (95:5, v:v) and analyzed directly using a
supercritical fluid chromatograph (Dionex 602 series; Dionex,
Sunnyvale, CA) (16)
. The detection was accomplished using
a flame ionization detector, and the quantitation was obtained using
the integrated peak area of the triglyceride components. The
chromatograms of the molecular species of the triglycerides in the STG
and PM are shown in Figures 2A
and
B
, and the quantitation is summarized in Table 3
. The newly created triglyceride species in the STG are clearly shown in
the region from ECN 32 to ECN 42. No triglycerides with ECN between 32
and 42 were present in the PM. The majority of the triglycerides in the
STG contained two molecules of MCFA and one molecule of LCFA. These
fatty acids were randomly esterified at the sn-1, -2, or -3
position of the triglyceride backbone.
|
|
The 2-monoglyceride composition of the triglycerides in the STG and PM
was analyzed using a method modified from Jensen et al.
(9)
. The triglycerides were hydrolyzed using a freshly
prepared lipase solution (Rhizopus arrhizus, Sigma
Chemical, EC 3.1.1.3, 1 x 108 U/L). The
2-monoglycerides were extracted from the reaction mixture and separated
using TLC. A solvent mixture containing chloroform/acetone (85:15, v:v)
was used to separate the triglyceride, diglyceride, 2-monoglyceride and
1, (3)-monoglycerides (9
,16
,22)
. The TLC zone for
2-monoglycerides was isolated, and the fatty acid composition was
analyzed. It should be noted that although the method described above
has been used for analyzing the 2-monoglyceride, it might overestimate
the presence of (n-3) polyunsaturated fatty acids (PUFA). This is
because certain long-chain PUFA of marine oils are resistant to
pancreatic lipase hydrolysis (23)
.
Statistical methods.
All values are expressed as means ± SEM. A two-way repeated-measures ANOVA was used to determine whether differences existed among groups for each hour of lipid, tocopherol and retinol infusion for each dependent variable. If the effect of either group or time was significant, Tukey’s Studentized Range Test was conducted to determine where the difference occurred. When a significant interaction was present, a one-way repeated-measures ANOVA was conducted in each group, and a one-way ANOVA was conducted at each time point of lymph collection. Significant findings were then subjected to Tukey’s Studentized Range Test to determine where the differences occurred. Results were considered statistically significant if the probability was <5%.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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The mean fasting lymph flow for all four groups of rats (n
= 6–8), two I/R (STG and PM) and two controls (STG and PM),
varied between 2.2 and 2.4 mL/h. In all groups, lymph flow increased
significantly after lipid infusion and reached a maximum output between
3.4 and 4.1 mL/h during h 3–4 after lipid infusion. After peaking at h
4, lymph flow declined slowly and reached a steady-state output of
3 mL/h during h 7 and 8 after lipid infusion. There were no
differences in the lymph flow rates between the STG- and PM-treated
rats in either the control or I/R group.
Lymphatic 14C--tocopherol output.
Figure 3
shows the lymphatic 14C--tocopherol output
during the first 8 h after the gastric feeding of either STG or PM
in the sham-operated controls. The lymphatic output of
14C--tocopherol increased in both groups
during the first 4 h and reached a steady state from h 4 to 8
after administration of the lipid. However, there was a significant
difference in the amounts of lymphatic radioactive tocopherol output
after the feeding of either STG or PM. Gastric infusion of STG
significantly improved lymphatic
14C--tocopherol output 2–8 h after lipid
feeding (P < 0.01) and significantly increased overall
tocopherol output compared with rats given PM.
|
). Similar to the controls, the lymphatic
14C--tocopherol output was significantly
higher overall (8-h lymph collection) and for h 3–8 (P
< 0.01) in rats fed the STG compared with those fed the PM.
|
The lymphatic radioactive retinol output in sham-operated control
rats is shown in Figure 5
. In both the STG- and PM-fed rats, lymphatic
3H-retinol output increased and reached a steady
output by h 2 after the administration of each lipid. In both groups,
the lymphatic 3H-retinol output slowly declined
after h 4 of lipid infusion. With the exception of h 1 and 7, the
lymphatic radioactive retinol outputs were significantly higher overall
and for individual time points in the STG-fed rats compared with
the PM-fed rats (P < 0.01). Thus, STG
significantly enhanced the lymphatic transport of retinol into lymph.
|
). The lymphatic retinol output in the rats fed STG maintained a
significantly higher output throughout the 8-h infusion period
compared with rats given the PM (P < 0.01).
The lymphatic retinol output decreased between h 2 and 8 in the
PM-fed group with differences between the two groups significant at
h 6, 7 and 8 during the infusion period (P < 0.01). In
addition, I/R rats fed STG were the only group that maintained a steady
lymphatic retinol output during the 2- to 8-h infusion period, whereas
control (STG and PM fed rats) and I/R rats given the PM experienced a
decline in lymphatic retinol output during the experimental period.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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. The goals of this study were to explore further the
potential absorptive benefits of STG in malabsorptive conditions.
Absorption of lipophilic compounds such as fat-soluble vitamins is
impaired in diseases that cause fat malabsorption (Crohn’s disease,
short-bowel syndrome, cystic fibrosis). As such, we compared the
intestinal absorption and lymphatic transport of tocopherol and retinol
when delivered gastrically with either STG or its equivalent PM under
normal conditions and after I/R injury to the small bowel in rats.
These lymph fistula rat models are established methods
(10
,17)
that accurately measure and quantify the
absorption of physiologic quantities of lipophilic compounds after a
test meal.
This study showed that under steady-state conditions, the amount of
14C--tocopherol and
3H-retinol transported into lymph was
significantly higher in the STG-fed rats compared with PM-fed
rats in both those with or without I/R injury. Further examination of
the lymphatic output data indicated that both normal and I/R rats fed
the STG had earlier steady-state outputs of tocopherol and retinol
and maintained 30% higher outputs in lymph throughout the 8-h lymph
collection period compared with PM-fed rats. We consider these
observations quite important when taken in conjunction with data from
our previous study showing lipid and key EFA absorption benefits after
feeding STG (16)
. Although I/R did not significantly
reduce the lymphatic transport of fat-soluble vitamins in either
group of rats, STG infusion resulted in absorptive benefits similar to
those observed in uninjured animals.
There may be several reasons explaining the absorption benefits we
observed when feeding STG under both normal and malabsorptive
conditions. The advantages of STG may be due to the fundamental
differences in their digestion, chylomicron formation and lymphatic
transport of triglycerides compared with PM of constituent oils as
outlined earlier. These studies show that STG have a unique molecular
structure that enhances lymphatic absorption of LCFA and MCFA, as
evidenced by the triglyceride molecular species analysis of the two
oils we studied (Table 3)
. The relative distribution of MCFA in the
triglycerides of both oils is represented by the calculated ECN (sum of
the triglyceride acyl side chains). STG contains an abundance of
triglyceride species consisting of various mixtures of MCFA and LCFA
(ECN 32–43), which are absent in the PM. In contrast, the PM had a
higher proportion of triglycerides with ECN numbers < 30 (mainly
MCFA) or > 50 (mainly LCFA). Therefore, it is reasonable to
assume that the novel triglyceride species produced from the
interesterification of fish oil and MCT are responsible for the
increased absorption and lymphatic transport of lipid, tocopherol and
retinol in rats both with and without I/R injury. These unique
triglycerides may serve as a carrier vehicle to facilitate the delivery
of tocopherol and retinol.
Because fat-soluble vitamins are not well absorbed from the
gastrointestinal tract, research has focused on new strategies to
improve their absorption. Although tocopherol and retinol are absorbed
with lipid, packed into chylomicrons and then transported to the
general circulation via the lymphatic system, substantial evidence
suggests that it is not possible to predict the efficiency of vitamin E
absorption on the basis of the efficiency of triglyceride absorption.
Research has shown that the intestinal absorption of tocopherol can be
enhanced by solubilization with MCT compared with LCT
(24
25
26
27)
. This may be because MCFA are more soluble in
water than LCT, thus creating suitable conditions for improved
intestinal uptake of tocopherol (24)
. However, the
absorption of MCT occurs mainly via the portal circulation rather than
the lymphatic route; thus, the absorption of vitamin E can be
significantly increased without enhancing intestinal lipid transport in
lymph (25
26
27)
. Muralidhara and Hollander
(28)
demonstrated that inclusion of PUFA in bile salt
micelles suppresses the absorption of -tocopherol by rat small
intestine, thereby supporting that triglyceride absorption is not
always associated with enhanced absorption of fat-soluble vitamins.
MacMahon and Thompson (29)
demonstrated in rats with bile
diversion that a polar lipid, such as oleic acid, is well absorbed into
the mesenteric lymphatic system from an emulsion (bile salt micelles),
whereas the nonpolar -tocopherol is poorly absorbed from the
emulsion. Our previous study (17)
showed that I/R injury
to the rat small intestine significantly reduced lymphatic triglyceride
output compared with normal rats. It also demonstrated, however, that
I/R injury did not significantly reduce the lymphatic transport of
-tocopherol and retinol compared with sham-operated controls,
thus providing further evidence that factors affecting the digestion,
chylomicron packaging and lymphatic uptake of triglyceride and
fat-soluble vitamins are not the same.
The results of this study offer a new approach toward enhancing the
intestinal absorption of tocopherol and retinol using STG. These
triglycerides are chemically distinct and offer unique advantages from
their constituent MCT and LCT. STG contain MCFA and thus provide a
vehicle for rapid hydrolysis and absorption due to smaller molecular
size and greater water solubility in comparison to LCT. Although STG
contain MCFA, it is likely that the interplay of the new triglyceride
species contributes to the increased tocopherol and retinol absorption.
The precise mechanism of these absorptive benefits remains to be
investigated, but it may lie in the packaging and secretion of
chylomicrons. Most likely, it is caused by a difference in the
reesterification and packaging of the absorbed STG, tocopherol and
retinol into chylomicrons. How these are packaged better into
chylomicrons with STG vs. PM remains to be elucidated and is currently
being investigated in our laboratory. Supporting this theory are
observations from our previous study showing increases in lymphatic
phospholipid and cholesterol outputs with STG that resulted in the
formation of more and larger or more efficiently packaged chylomicrons
(16)
. We cannot rule out the possibility in this study,
however, the effects that tocopherol and retinol may have played on the
absorption of one another.
In summary, we have presented novel information demonstrating that the digestion and transport of tocopherol and retinol to lymph is more efficient when combined with randomly interesterified STG compared with PM under normal conditions and in rats with small bowel dysfunction. Thus, STG provide the opportunity to better deliver key EFA and to potentiate improved absorption of fat-soluble vitamins and other lipid-soluble compounds (i.e., natural/synthetic lipophilic drugs) in children and adults in the normal state and in malabsorptive states, such as Crohn’s disease, short-bowel syndrome, cystic fibrosis and post-trauma.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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3 Abbreviations used: ECN, equivalent carbon number; EFA, essential fatty acids; I/R, ischemia/reperfusion; LCFA, long-chain fatty acids; LCT, long-chain triglycerides; MCFA, medium-chain fatty acids; MCT, medium-chain triglycerides; PM, physical mixture; PUFA, polyunsaturated fatty acids; SMA, superior mesenteric artery; STG, structured triglycerides.
Manuscript received February 26, 2001. Initial review completed March 30, 2001. Revision accepted May 22, 2001.
|
REFERENCES |
|---|
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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1. DeMichele S. J., Karlstad M. D., Babayan V. K., Istfan N., Blackburn G. L., Bistrian B. R. Enhanced skeletal muscle and liver protein synthesis with structured lipid in enterally fed burned rats. Metabolism 1988;37:787-795[Medline]
2.
DeMichele S. J., Karlstad M. D., Bistrian B. R., Istfan N., Babayan V. K., Blackburn G. L. Enteral nutrition with structured lipid: effect on protein metabolism in thermal injury. Am. J. Clin. Nutr. 1989;50:1295-1302
3. Maiz A., Yamazaki K., Sobrado J., Babayan V. K., Moldawer L. L., Bistrian B. R., Blackburn G. L. Protein metabolism during total parenteral nutrition (TPN) in injured rats using medium-chain triglycerides. Metabolism 1984;33:901-909[Medline]
4. Mok K. T., Maiz A., Yamazaki K., Sobrado J., Babayan V. K., Moldawer L. L., Bistrian B. R., Blackburn G. L. Structured medium-chain and long-chain triglyceride emulsions are superior to physical mixtures in sparing body protein in the burned rat. Metabolism 1984;33:910-915[Medline]
5. Teo T. C., DeMichele S. J., Selleck K. M., Babayan V. K., Blackburn G. L., Bistrian B. R. Administration of structured lipid composed of MCT and fish oil reduces net protein catabolism in enterally fed burned rats. Ann. Surg. 1989;210:100-107[Medline]
6. Teo T. C., Selleck K. M., Wan J.M.F., Pomposelli J. J., Babayan V. K., Blackburn G. L., Bistrian B. R. Long-term feeding with structured lipid composed of medium-chain and n-3 fatty acids ameliorates endotoxic shock in guinea pigs. Metabolism 1991;40:1152-1159[Medline]
7. McKenna M. C., Hubbard V. S., Pieri J. G. Linoleic acid absorption from lipid supplements in patients with cystic fibrosis with pancreatic insufficiency and in control subjects. J. Pediatr. Gastroenterol. Nutr. 1985;4:45-51[Medline]
8. Hubbard V. S., McKenna M. C. Absorption of safflower oil and structured lipid preparations in patients with cystic fibrosis. Lipids 1987;22:424-428[Medline]
9.
Jensen G. L., McGarvey N., Taraszewski R., Wixson S. K., Seidner D. L., Pai T., Yeh Y. Y., Lee T. W., DeMichele S. J. Lymphatic absorption of enterally-fed structured triacylglycerol versus physical mix in a canine model. Am. J. Clin. Nutr. 1994;60:518-524
10.
Tso P., Karlstad M. D., Bistrian B. R., DeMichele S. J. Intestinal digestion, absorption and transport of structured triacylglycerols and cholesterol in rats. Am. J. Physiol. 1995;268:G568-G577
11. Christensen M. S., Mullertz A., Hoy C. E. Absorption of triacylglycerols with defined or random structure by rats with biliary and pancreatic diversion. Lipids 1995;30:521-526[Medline]
12. Christensen M. S., Hoy C. E., Redgrave T. G. Lymphatic absorption of n-3 polyunsaturated fatty acids from marine oils with different intramolecular fatty acid distributions. Biochim. Biophys. Acta 1994;1215:198-204[Medline]
13.
Christensen M. S., Hoy C. E., Becker C. C., Redgrave T. G. Intestinal absorption and lymphatic transport of eicosapentaenoic (EPA), docosahexaenoic (DHA), and decanoic acids: dependence on intramolecular triacylglycerol structure. Am. J. Clin. Nutr. 1995;61:56-61
14. Jensen M. M., Christensen M. S., Hoy C. E. Intestinal absorption of octanoic, decanoic, and linoleic acids: effect of triacylglycerol structure. Ann. Nutr. Metab. 1994;38:104-116[Medline]
15. Kenler A. S., Swails W. S., Driscoll D. S., DeMichele S. J., Daley B., Babineau T. J., Peterson M. B., Bistrian B. R. Early enteral feeding in postsurgical cancer patients: fish oil structured lipid-based polymeric formula versus a standard polymeric formula. Ann. Surg 1996;223:316-333[Medline]
16.
Tso P., Lee T., DeMichele S. J. Lymphatic absorption of structured triglycerides vs. physical mix in a rat model of fat malabsorption. Am. J. Physiol. 1999;277:G333-G340
17.
Fujimoto K., Price V. H., Granger D. N., Specian R., Bergstedt S., Tso P. Effect of ischemia-reperfusion on lipid digestion and absorption in rat intestine. Am. J. Physiol. 1991;260:G595-G602
18. Bollman J. L., Cain J. C., Grindlay J. H. Techniques for the collection of lymph from the liver, small intestine or thoracic duct of the rat. J. Lab. Clin. Med. 1948;33:1349-1352
19. Babayan V. K. Medium-chain triacylglycerols and structured lipids. Lipids 1987;22:417-420[Medline]
20.
Blankenhorn D. H., Ahrens E. H. Extraction, isolation, and identification of hydrolytic products of triglyceride digestion in man. J. Biol. Chem. 1955;212:69-81
21. Lee T. W., Hastilow C. I. Quantitative determination of triacylglycerol profile of structured lipid by capillary supercritical fluid chromatography and high-temperature gas chromatography. J. Am. Oil Chem. Soc. 1999;76:1405-1413
22. Wood R., Snyder F. Chemical and physical properties of isomeric glyceryl monoethers. Lipids 1967;2:161-171
23. Bottino N. R., Vanderburg G., Reiser R. Resistance of certain long-chain polyunsaturated fatty acids of marine oils to pancreatic lipase hydrolysis. Lipids 1967;2:489-493[Medline]
24. Gallo-Torres E., Ludorf J., Brain M. The effect of medium-chain triglycerides on the bioavailability of vitamin E. Int. J. Vitam. Nutr. Res. 1978;48:240-249[Medline]
25.
Kimura T., Jukui E., Kageyu A., Kurohara H., Kurosaka Y., Nakayama T., Morita Y., Shibusawa K., Ohsawa S., Takeda Y. Enhancement of oral bioavailability of d--tocopherol acetate by lecithin-dispersed aqueous preparation containing medium-chain triglycerides in rats. Chem. Pharm. Bull. 1989;37:439-441
26.
Fukui E., Kurohara H., Kageyu A., Kurosaki Y., Nakayama T., Kimura T. Enhancing effect of medium-chain triglycerides on intestinal absorption of d--tocopherol acetate from lecithin-dispersed preparations in the rat. J. Pharmacobio-Dyn. 1989;12:80-86[Medline]
27.
Fukui E., Tabuchi H., Kurosaki Y., Nakayama T., Kimura T. Further investigations of enhancing effect of medium-chain triglycerides on d--tocopherol acetate absorption from lecithin-dispersed preparations in rat small intestine. J. Pharmacobio-Dyn. 1989;12:754-761[Medline]
28.
Muralidhara K. S., Hollander D. Intestinal absorption of -tocopherol in the unanesthetized rat. The influence of luminal constituents on the absorptive process. J. Lab. Clin. Med. 1977;90:85-91
29.
MacMahon M. T., Thompson G. R. Comparison of the absorption of a polar lipid, oleic acid, and a non-polar lipid, -tocopherol from mixed micellar solutions and emulsions. Eur. J. Clin. Investig. 1970;1:161-166[Medline]
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