Chemistry Reference
In-Depth Information
Unfortunately, no effective pharmaceutical treatment exists or when existing is unac-
ceptably toxic.
52
This has resulted in a need for additional modalities for the treat-
ment of IBS. In this perspective, pre- and probiotics appear as attractive alternatives
(see recent reviews
53,54
). Data from human intervention studies and especially results
from recent animal studies clearly indicate that prebiotics have an impact on the
immune system: Immune cells of the GALT (gut-associated lymphoid tissue) includ-
ing Peyer's patches are primarily responsive to the oral administration of prebiot-
ics.
55
However, a consequence of feeding the currently favored prebiotics (inulin,
FOS, trans-galacto-oligosides, and lactulose) is increased gas production in the gut,
which might preclude prebiotic use in diarrhea-predominant IBS, or where bloat-
ing or gas are prominent symptoms, but might allow their mild laxative properties
to be useful in constipation-predominant IBS.
53
A few small open trials have been
performed, but thus far no larger and randomized trial has been reported. However,
a recent small open-label trial supplementing 15 g/day of a mixture of oligofructose
(70 percent) and inulin (30 percent) reports significant reduction in disease activity
(Harvey Bradshaw index fell from 9.8, SD 3.1 to 6.9 SD 3.4,
p
= 0.01) in parallel with
a significant increase in fecal bifidobacteria concentration (from 8.8, SD 0.9 log10 to
9.4, SD 0.9 log10 cells/g dry feces
p
= 0.001). Also the interleukin 10 (IL-10) posi-
tive dendritic cells increased (from 30 to 53 percent,
p
= 0.06), and the percentage
of dendritic cells expressing Toll-like receptor 2 (TLR2) and TLR4 increased from
1.7 to 36.8 percent,
p
= 0.08, and from 3.6 to 75.4 percent,
p
= 0.001),
56
respectively,
which offers hope for the future.
Other dietary fibers have also been tried in various groups of abdominal pain. A
recent Cochrane review was unable to find any evidence that fiber supplements, lac-
tose-free diets, or
Lactobacillus
supplementation is effective in the management of
children with recurrent abdominal pain.
57
However, a study in adult patients reports
significant success with fibers other than the classical prebiotics. In one study, 188
adult patients with IBS were classified as having diarrhea-predominant, constipation-
predominant, or changeable bowel habit type IBS and randomly assigned to groups
receiving 30 g/day of wheat bran or 5 g/day of guar gum (PHGG).
58
After 4 weeks,
patients were allowed to switch group, depending on their subjective evaluation of
their symptoms. Both fiber and PHGG were effective in improving pain and bowel
habits. Significantly more patients switched from fiber to PHGG (49.9 percent) than
from PHGG to fiber (10.9 percent) at 4 weeks. Intention-to-treat analysis showed a
significantly greater success in the PHGG group (60 percent) than in the fiber group
(40 percent). In addition, significantly more patients in the PHGG group reported a
greater subjective improvement than those in the fiber group. It was concluded that
improvements in core IBS symptoms were observed with both bran and PHGG, but
the latter was better tolerated and preferred by patients.
58
The capsaicin (chili pepper) receptor (TRPV1) is known to play an important
role in visceral pain and hypersensitivity states. It is of special interest that the num-
bers of TRPV1-immunoreactive fibers was found to be increased by 3.5 times in
biopsies from patients with IBS compared with controls (
p
< 0.0001).
59
Substance
P-immunoreactive fibers (
p
= 0.01), total nerve fibers (PGP 9.5) (
p
= 0.002), mast
cells (c-kit) (
p
= 0.02), and lymphocytes (CD3) (
p
= 0.03) were also all significantly
