Antilipemic Activity of an Extract of Hog Gastric Mucosa

Antilipemic Activity of an Extract of Hog Gastric Mucosa
By AURELIO CANTONE, M.D.,
VINCENZO RULLI, M.D.,
AND BALDO ROSSI,
M.D.
In recent years numerous studies have been made on the clearing effect exerted by heparin on hyperlipemic plasma, specially in connection with the problem of atherogenesis.
The present paper deals with investigations, carried out on both animals and men, concerning the hypoeholesteremic, plasma-clearing, and lipotropie effects, as well as the
inhibitory action on the electrocardiographs changes associated with alimentary hyperlipemia, exerted by orally active extracts of gastric juice and hog gastric mucosa.
OLLOWING Halm's observation1 that
heparin administered parenterally exerts
a clearing effect on lipemic plasma, Korn2 and
Anfinseii3 demonstrated that this effect is due
to the action of a lipase, called lipoprotein lipase, because it causes hydrolysis of the triglycerides bound to beta-lipoproteins and chylomicrons. Korn4 stated that the lipoprotein
lipase is a mucoprotein which probably contains a polysaccharide component similar to
that of heparin. In all likelihood administered heparin has the function of activating
this lipolytic ferment present in the tissues
and of releasing it into the blood stream.
In addition to the clearing effect exerted by
heparin through enzymic mechanisms, other
clearing effects of a nonenzymic nature have
been reported. These can be produced,
though indirectly, by bacterial polysaccharides5' ° and probably also by polysaceharide
derivatives existing in the gastric mucosa.7
In the course of a series of researches on the
properties of a mucin compound obtained
from the gastric juice of normal men, some of
us found that in the rabbit the oral administration of this compound is followed by a mild
and fleeting but significant increase of the
plasma-clearing action, determined in vitro on
the plasma-lipemic substrate system.8 The
oral administration of this mucin compound to
rabbits rendered hyperlipemic by the intravenous injection of an emulsion of vegetable
oil (Ediol Schenley) produces a decrease of
F
the optical density of the plasma. In addition, this compound has a protective effect
against fatty liver of alimentary origin in
rats.9
Subsequently a fraction was precipitated
from the gastric juice with eetyltrimethylammonium bromide (Schuchardt) ; this fraction
has the same properties as the crude mucin
compound10 (fig. 1). The fact that it forms
a precipitate with the quaternary ammonium
derivative used11 and stains metachromatically
with toluidine blue12 suggests that the material contains an acid aminopolysaccharide.
A physically homogeneous substance was
isolated from hog gastric mucosa which is
probably a nonsulfurated acid aminopolysaccharide, because of its high hexuronic acid
and hexosamine content and the absence of
sulfur. This substance has an average molecular weight of about 5,000, shows a marked
anodic mobility, is precipitated by cetyltrimethylammonium bromide, and stains metachromatically with toluidine blue.12"14 When
administered by mouth, it exerts an in vivo
clearing effect in rabbits rendered hyperlipemie by injecting a lipidic emulsion (fig. 2)
and a lipotropie action in fatty liver of dietarj7
origin in rats. 7 - 13 Furthermore, experiments
involving prolonged treatment with this substance show that it has an hypoeholesteremic
effect in rabbits fed a diet rich in cholesterol13- 15 (table 1).
A crude extract of hog gastric mucosa with
a 10 per cent aminopolysaccharide content
showed an antilipemic action (cholesterol, fatty acids) in a group of elderly persons.1"
Other authors17- l s also reported that this extract exerts an hypoeholesteremic effect in
From the Istituto Ricerche Ciirlo Erba, Milnno
(Dr. V. Capraro, Director) and the Ceutro per ]a
Lotta contro il Reumatismo e ]e Cardiopntie di l{iini:i
(Dr. V. Puddu, Director), Italy.
Received for publication September 29, 1958.
291
Circulation Research, Volume VII, May 1959
292
CAXTONE, KULLI, ROSSI
TABLE 1.—Effect
of the Oral Administration of the Sog Gastric Mucin Extract (5 mg./
Kg./Day) in Hyperlipemic Rabbits*
Controls
No. of Mean value
rabbits
±S.E.
Changes of total
fatty acids
Changes of total
cholesterol
Changes of esterifled
cholesterol
395.3
±11.7
327.4
± 8.7
241.6
±14.0
6.38
±0.57
8.26
±0.68
6
6
6
ft/a ratio
6
Total lipids
(aorta)
0
Treated with gastric mucin extract
No. of Mean value
rabbits
±S.E.
6
6
6
6
5
290.7
±12.4
246.7
± 9.1
162.5
± 8.4
3.99
±0.32
4.60
±0.31
t
N
6.07
10
<0.001
6.38
10
<0.001
4.85
10
<0.001
3.66
10
0.01>p>0.001
4.41
8
0.01>p>0.001
V
*The values of the changes of total fatty acids, and of total and esterified cholesterol are in
mg./lOO ml. of plasma. The mean values of total lipids of the thoracic aorta are in mg./lO
Gm. of dry thoracic aorta.
t = t of Student. X=number of degrees of freedom. P=signifieance. S.E.=standard error.
0
30
60
90
120 min.
0
30
60
90
120 min
FIG. 1 heft. Jlean values and standard error of the optical density (Beckman DTJ spectrophotometer: X = 540 HIM) of the plasma of rabbits treated with 0.5 ml./Kg. of lipidie
emulsion intravenously (o—o) and of the plasma of rabbits treated with 0.5 ml./Kg. of
lipidie emulsion intravenously as well as with 5 mg./Kg. by mouth of the fraction precipitated
with cctyltrimethylammonium bromide from the gastric juice mucine extract (•—*). This
fraction was given 15 minutes after the lipidie emulsion.
FIG. 2 Right. Mean values and standard error of the optical density (Beckman DTJ spectrophotometer: X = 540 m/i) of tin- plasma of rabbits treated with 0.5 ml./Kg. of lipidie
emulsion intravenously (o—o) and of the plasma of rabbits treated with 0.5 ml./Kg. of
lipidie emulsion intravenously as well as with 3.75 mg./Kg. by mouth of the acid aminopolysaccharide fraction obtained from the mucin extract of hog gastric mucosa (•—*). In
this experiment the fraction was given at the same time as the lipidie emulsion.
293
HOG EXTRACT AXTIL1PEM1C ACTIVITY
Optical 1
density
85-
n
m
7055-
50
Hours 1
2
3
4
5
FIG. 3. Mean values of plasma optical density
(Leitz-Bouy photometer: X = 640 m/») in a group
of atherosclerotic patients fed a fat meal (200 Gra.
of milk cream), without {solid line) and with {broken
line) administration of crude gastric mucin (about
3.5 mg./Kg. of body weight). (Reproduced from
figure 1 of an article by T)r. Rulli and Dr. Rossi,
Circulation 18: 400, 1958.)
pathologic hyperlipidemic states. In an investigation carried out both on young people
clinically free from atherosclerosis, and on
patients presumed to be atherosclerotic because of histories of myoeardial infarction
and/or definite evidence of coronary insufficiency, we have found that under basal conditions the oral administration of crude gastric
mucin from hog stomach is able to decrease
the plasma optical density (as determined by
the Leitz-Rouy photometer). The average
decreases in the two groups were 30 and 26
per cent respectively. This difference in the
average decrease of plasma optical density
between the two groups is not significant.19
The clearing effect exerted by gastric mucin
under basal conditions is even more striking
when the mucin is administered to "atherosclerotic" patients fed a fat meal. In such
'patients the marked hyperlipemia induced by
a fat meal in control experiments was always
greatly reduced when gastric mucin was given
at the same time as the fat meal (about 3.5
mg./Kg. of body weight) (fig. 3). 20
Finally, in line with the results obtained
in previous investigations with heparin,21- -gastric mucin administered simultaneously
with a fat meal prevented (either fully or
in part), in 50 per cent of the anginal patients
FIG. 4 Top. Showing the changes of the repolarization phase induced by a fat meal in the electrocardiogram of 2 anginal patients with old myoeardial infarcts, and of their inhibition when crude gastric
mucin is administered at the same time as the fat
meal. The plasma optical density shows similar
changes. Top, electrocardiogram recorded before the
test: optical density 65. Middle, electrocardiogram
recorded 3 hours after a fat meal: optical density 75.
Bottom, electrocardiogram recorded 3 hours after a
fat meal with the addition of gastric mucin: optical
density 60.
FIG. 5 Bottom. Top, electrocardiogram recorded before the test: optical density 62. Middle, electrocardiogram recorded 3 hours after a fat meal: optical density 85. Bottom, electrocardiogram recorded 3 hours
after a fat meal with the addition of gastric mucin:
optical density 69. {Reproduced from figures 2 and 3
of an article by Dr. Rulli and Dr. Rossi, Circulation
18: 400, 1958.)
CANTONE, KULL1, ROSSI
294
thus studied, the electrocardiographic changes
associated with a fat meal, the conditions of
the experiment being identical-" (figs. 4 and
5).
Concluding, we have the impression that
the normal gastric juice of man contains an
acid aminopolysaccharide fraction, which,
when administered by mouth, acts indirectly
on the state of dispersion of the plasma lipids,
and which in all likelihood, in addition to
other physiologic function, plays a role in
the etiology of certain disease states.
SUMMARY
A mucin compound obtained from the
human gastric juice exerts a plasma-clearing
effect in rabbits rendered hyperlipemie and
has a prolonged effect against fatty liver of
alimentary origin in rats.
An extract of hog gastric mucosa, which
in all likelihood is chemically a uonsulfurated
acid aminopolysaccharide, exerts a clearing
effect in rabbits and men, an hypocholesteremic action, an antilipemic effect, a lipotropic
action in fatty liver of dietary origin in rats,
and inhibits the electrocardiographic changes
associated with a fat meal in men.
It is possible that, in addition to their
physiologic function, such mucins, which contain an aminopolysaccharide fraction, by acting on the state of dispersion of the plasma
lipids, play a role in the etiology of certain
disease states.
SuMMARlO IN
IJSTTERLINGUA
Un composite mucinic obtenite ab le succo
gastric de humanos exerce un effecto clarificatori super le plasma de couilios rendite
hyperlipemie per medio de dietas experimental. Illo exerce uii effecto protectori contra le disveloppamento de un hepate adipose
de origine alimentari in rattos.
Un extracto de porcin mucosa gastric—le
qual, in terminos chimie, es probabilissimemente un aminopolysaecharido de acido nonsulfurate—exerce un effecto clarificatori in
eonilios e humauos, un action hypocholesterolemic, un effecto antilipemic, e un action
lipotropic in casos de hepate adipose de
origiue alimentari in rattos, e un effecto inhibitori contra le alterationes electrocardiographic associate con le ingestion de repastos
grasse in humanos.
II es possibile que—a parte lor function
physiologic—tal mucinas (que eontine un
fraction aminopolysaccharidic) es implicate—
per ager super le state de dispersion del
lipidos del plasma—in le etiologia de certe
conditiones pathologic.
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