26 research outputs found
Diabetic autonomic neuropathy: evidence for apoptosis in situ in the rat
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75065/1/j.1365-2982.2004.00524.x.pd
Changes in the gastric enteric nervous system and muscle: A case report on two patients with diabetic gastroparesis
<p>Abstract</p> <p>Background</p> <p>The pathophysiological basis of diabetic gastroparesis is poorly understood, in large part due to the almost complete lack of data on neuropathological and molecular changes in the stomachs of patients. Experimental models indicate various lesions affecting the vagus, muscle, enteric neurons, interstitial cells of Cajal (ICC) or other cellular components. The aim of this study was to use modern analytical methods to determine morphological and molecular changes in the gastric wall in patients with diabetic gastroparesis.</p> <p>Methods</p> <p>Full thickness gastric biopsies were obtained laparoscopically from two gastroparetic patients undergoing surgical intervention and from disease-free areas of control subjects undergoing other forms of gastric surgery. Samples were processed for histological and immunohistochemical examination.</p> <p>Results</p> <p>Although both patients had severe refractory symptoms with malnutrition, requiring the placement of a gastric stimulator, one of them had no significant abnormalities as compared with controls. This patient had an abrupt onset of symptoms with a relatively short duration of diabetes that was well controlled. By contrast, the other patient had long standing brittle and poorly controlled diabetes with numerous episodes of diabetic ketoacidosis and frequent hypoglycemic episodes. Histological examination in this patient revealed increased fibrosis in the muscle layers as well as significantly fewer nerve fibers and myenteric neurons as assessed by PGP9.5 staining. Further, significant reduction was seen in staining for neuronal nitric oxide synthase, heme oxygenase-2, tyrosine hydroxylase as well as for c-KIT.</p> <p>Conclusion</p> <p>We conclude that poor metabolic control is associated with significant pathological changes in the gastric wall that affect all major components including muscle, neurons and ICC. Severe symptoms can occur in the absence of these changes, however and may reflect vagal, central or hormonal influences. Gastroparesis is therefore likely to be a heterogeneous disorder. Careful molecular and pathological analysis may allow more precise phenotypic differentiation and shed insight into the underlying mechanisms as well as identify novel therapeutic targets.</p
Myenteric plexus in the gastrointestinal tract of non-obese diabetic mice
The myenteric plexus was investigated in the gastrointestinal tract of pre-diabetic and diabetic nonobese diabetic (NOD) mice. The plexus was immunostained by the avidin-biotin complex method, using a general marker for nerve elements, namely protein geneproduct 9.5. The nerve fibres were quantified by pointcounting and the number of ganglia and their area were determined by image analysis. The relative volume density of the nerve fibres in duodenal muscularis propria was found to be significantly reduced in of both pre-diabetic and diabetic NOD mice. There was no statistical difference between controls and NOD mice regarding relative volume density of nerve fibres in antral and colonic muscularis propria. The number of myenteric ganglialmm baseline was significantly decreased in the duodenum of diabetic NOD mice, and showed a non-statistically significant tendency to decrease in pre-diabetic mice. In the antrum and colon, there was no difference between the controls and NOD mice regarding the number of ganglialmm baseline. Nor was there any significant difference between controls and NOD mice in the area of myenteric ganglia in either antrum, duodenum or colon. It is concluded that the changes in the duodenal myenteric plexus of NOD mice are prior to the onset of diabetes. It is suggested that the absence of changes in the antral and colonic myenteric plexus when using a general marker for neuroelements does not preclude a possible change in cholinergic, adrenergic or peptidergic innervation
Myenteric plexus of obese diabetic mice (an animal model of human type 2 diabetes)
The myenteric plexus of the gastrointestinal
tract was investigated in the obese diabetic mouse, an
animal model of human type 2 diabetes. Sections were
immunostained by the avidin-biotin complex method,
using a general nerve marker, protein gene product 9.5
(PGP 9.5), as well as antibodies to several important
neurotransmitters. Computerized image analysis was
used for quantification. When diabetic mice were
compared with controls, no difference was found in the
density of PGP 9.5-immunoreactive (IR) nerve fibres in
antrum, duodenum or colon. In antrum and duodenum,
diabetic mice showed a decreased number of vasoactive
intestinal peptide (V1P)-IR neurons in myenteric ganglia
as well a decreased relative volume density in myenteric
plexus (though not significantly in antrum, p=0.073). No
difference was found regarding VIP-IR nerves in colon.
The volume density of nitric oxide synthase (NOS)-IR
nerve fibres was decreased in antrum and duodenum of
diabetic mice, whereas no difference was found in colon.
The density of galanin-IR neme fibres was decreased in
duodenum. Whereas neuropeptide Y (NPY)- and
vesicular acetylcholine transporter (VAChT)-IR nerve
fibres was increased in density in colon of diabetic mice, no difference was found in antrum and duodenum.
Regarding substance P, there was no difference between
diabetic and control mice in antrum, duodenum or colon.
The present study shows that gut innervation is affected
in this animal model of human type 2 diabetes. It is
possible that the present findings may have some
relevance for the gastrointestinal dysfunctions seen in
patients with type 2 diabetes
Myenteric plexus in the gastrointestinal tract of non-obese diabetic mice
The myenteric plexus was investigated in the
gastrointestinal tract of pre-diabetic and diabetic nonobese
diabetic (NOD) mice. The plexus was immunostained
by the avidin-biotin complex method, using a
general marker for nerve elements, namely protein geneproduct
9.5. The nerve fibres were quantified by pointcounting
and the number of ganglia and their area were
determined by image analysis. The relative volume
density of the nerve fibres in duodenal muscularis
propria was found to be significantly reduced in of both
pre-diabetic and diabetic NOD mice. There was no
statistical difference between controls and NOD mice
regarding relative volume density of nerve fibres in
antral and colonic muscularis propria. The number of
myenteric ganglialmm baseline was significantly
decreased in the duodenum of diabetic NOD mice, and
showed a non-statistically significant tendency to
decrease in pre-diabetic mice. In the antrum and colon,
there was no difference between the controls and NOD
mice regarding the number of ganglialmm baseline. Nor
was there any significant difference between controls
and NOD mice in the area of myenteric ganglia in either
antrum, duodenum or colon. It is concluded that the
changes in the duodenal myenteric plexus of NOD mice
are prior to the onset of diabetes. It is suggested that the
absence of changes in the antral and colonic myenteric
plexus when using a general marker for neuroelements
does not preclude a possible change in cholinergic,
adrenergic or peptidergic innervation
Effect of diabetic state on co-localization of substance P and serotonin in the gut in animal models
Changes in the numbers of serotonin- and
substance P-immunoreactive (IR) cells occur in severa1
animal models of diabetes. It is not known, however,
whether these changes are a result of actual ceii loss or
are caused by modified gene expression in ceíls showing
co-localization of serotonin and substance P. The pattern
of mono- and co-expression of serotonin, as well as of
substance P, was therefore investigated in
gastrointestinal endocrine cells from animal models of
human type 1 and type 2 diabetes, namely non-obese
diabetic (NOD) and obese diabetic (oblob) mice.
Immunocytochemical staining by the avidin-biotin
complex method was performed for computerized image
analysis of each cell type, and by immunofluorescence
double staining to study co-localization. Tissues from
antrum, proximal duodenum and dista1 colon were
investigated. Co-localization of serotonin- and substance
P-IR was found in al1 investigated parts of the gut. In
antrum, substance P immunoreactivity was found
exclusively in serotonin-IR cells. In both NOD and
oblob mice there was a reduced number of substance PIR
cells, but an unchanged serotonin-IR cell count,
which thus tallies with a shut-off of substance P
expression in antral enterochromaffin cells. In
duodenum, both diabetes models showed a decreased
number of serotonin-IR cells. Furthermore there was a
decreased number of substance P-IR cells in the type 2 model. The proportion of serotonin-IR cells showing
substance P-immuno-reactivity was decreased in both
diabetic models, thus indicating a shut-off of substance
P-gene expression. However, this does not fully explain
the changes in duodenum, but the diabetic state probably
affects the number of mono-expressed cells as well. In
colon, no change was found in diabetic mice regarding
co-localization of substance P and serotonin. However,
pre-diabetic NOD mice showed a decreased proportion
of substance P in serotonin-IR cells, which might be
explained by the increased number of serotonin-IR cells, combined with an unchanged number of substance P-IR
cells. In conclusion, diabetic animal models of both type
1 and type 2 appear to have a combination of decreased
expression of substance P in serotonin-IR cells of both
antrum and duodenum, as well as a change in the
number of mono-expressed cells. The pattern in colon,
on the other hand, seems to be unaffected
Does diabetic state affect CO-localization of peptide W and enteroglucagon in colonic endocrine cells?
Background: Changes in the numbers of
PYY- and enteroglucagon-immunoreactive cells in colon
of animal models of human diabetes have been reported.
As these peptides CO-localize in the same cells it is
possible that the observed changes are a result of
changes in CO-localization. Methods: Animal models of
human type 1 and type 2 diabetes, namely the non-obese
diabetic (NOD) mouse and the obese (oblob) mouse,
were studied. As controls for the NOD mice, BALBIcJ
mice were used and for oblob mice, homozygous lean
(+l+) mice were used. Tissue samples from colon were
double-immunostained for PYY and enteroglucagon
according to the indirect immunofluorescence method.
Results: CO-localization of enteroglucagon and PYY was
found in colonic endocrine cells in all groups
investigated. Compared with controls, pre-diabetic NOD
mice showed a decreased proportion of enteroglucagon1PYY
CO-localization. There was no difference
in diabetic NOD mice or diabetic oblob mice when
compared with controls. Conclusions: Whereas the
number of cells containing solely enteroglucagon and
solely PYY increases in pre-diabetic NOD mice,
production of enteroglucagon in PYY-immunoreactive
cells decreases. Although the numbers of PYY and
enteroglucagon cells have been reported to be changed
in both diabetic NOD mice and in obese mice, the
balance between CO-expressing and mono-expressing
cells seems to be preserved
Diabetic state affects the innervation of gut in an animal model of human type 1 diabetes
Gastrointestinal symptoms in diabetic
patients are commonplace, and are believed to be due, at
least partly, to neuropathy of the gut. In the present
study, therefore, some important neurotransmitters in the
myenteric plexus were investigated in non-obese
diabetic mice, an animal model of human type 1
diabetes. For this purpose, immunocytochemistry was
applied on sections from antrum, duodenum and colon,
subsequently quantified by computerized image analysis.
Whereas the number of vasoactive intestinal peptide
(VIP)-positive neurons was increased in antral myenteric
ganglia of diabetic mice, there was a decreased density
of nerve fibres in muscularis propria. No difference was
seen in the VIP of duodenum and colon. Acetylcholinecontaining
nerve fibres showed an increased volume
density in muscularis propria of antrum and duodenum,
but a decreased density in colon of diabetic mice, as
compared with controls. There was a decreased number
of neurons containing nitric oxide synthase (NOS) in
myenteric ganglia of antrum and duodenum. No
difference was seen in density of NOS-containing nerve
fibres in muscularis propria. There was no difference
regarding neuropeptide Y (NPY) and galanin between
diabetic and control mice; nor was there any difference
between pre-diabetic NOD mice and controls regarding
all bioactive substances investigated. It is concluded that
the diabetic state affects the innervation of gut in this
animal model. The present findings may be of some relevance to the gastrointestinal symptoms seen in
patients with diabetes
Ghrelin cell density in the gastrointestinal tracts of animal models of human diabetes
Ghrelin cell density in the gastrointestinal
tract of animal models of human diabetes type 1 and 2
was investigated. The animals used were non-obese
diabetic (NOD) mice and obese diabetic mice. Ghrelin
cells were detected by immunohistochemistry and
quantified by computerized image analysis. Ghrelinimmunoreactive
cells were detected in all animals
studied. They were abundant in the oxyntic mucosa,
patchy and few in the duodenum and rare in the colon.
The density of ghrelin-immunoreactive cells decreased
in diabetic, pre-diabetic NOD mice and in obese diabetic
mice as compared to controls, though not statistically
significant. It was concluded that the reduced density of
ghrelin-immunoreactive cells in animal models of
human diabetes type 1 and 2 might explain the slow
gastric emptying and slow intestinal transit found in
diabetes gastroenteropathy