Reviewer’s report
Title: 
Overexpression of P-glycoprotein, MRP2, and CYP3A4 impairs intestinal
absorption of octreotide in rats with portal hypertension
Version: 
0 
Date: 
20 Jan 2019
Reviewer: 
Ying-Ying Yang
Reviewer's report:
comments to the BMGE-D-18-00745
Portal hypertension (PH) is the main cause of complications and death in liver
cirrhosis. Oral administration of octreotide (OCT), a drug that reduces PH by
constricting mesenteric arteries, is limited by marked intestinal first-pass
elimination. In this study, bile duct ligation (BDL) was used in rats to induce
liver cirrhosis with PH to examine the kinetics and molecular determinants of
intestinal absorption of OCT. Through both in situ and in vitro experiments in
jejunal segments, we observed that intestinal OCT absorption in both control and
PH rats is largely determined by Pglycoprotein (P-gp) and, to a lesser extent, by
multidrug resistance-associated protein 2 (MRP2). OCT transportation mediated
by P-gp and MRP2 was proved by Caco-2 cell experiment. The results of RT-
PCR, western blot, and immunohistochemical analyses suggested impaired
absorption of OCT in PH is determined in part by jejuna upregulation of these
two transporters. Using intestinal microsomes, we also found that cytochrome
P450 3A4 metabolizes OCT, and its upregulation in PH likely contributes to
impaired drug absorption. Thus inhibition of P-gp, MRP2, and CYP3A4 may
represent a valid option for decreasing intestinal first-pass effects on orally
administered OCT, thereby increasing its bioavailability to alleviate PH in
patients with cirrhosis. 
Major comments:
The rationales of study 
[1]. In the acute status of variceal bleeding, most patient need to be NPO. In
clinical practice, the intravenous infusion of octreotide needs to give through the
IV pump due to short half-life of octreotide. For chronic use of octreotide, there
is a long acting type of octreotide which call lantreotide. Accordingly, the
rationales to undergone this study need to be clarify.. 
[2].The standard treatment for long-term prophylaxis of the rupture of
esophageal varices is beta-blocker. So, the beta-blocker should be serves as
positive control. 
[3].The background description for mal-aborption of medicine in PH animals is
not clear. Specific references need to be provided. 
s text when adding your comments to the authors.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Unable to assess
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the
authors.
Unable to assess
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Unable to assess
Are you able to assess any statistics in the manuscript or would you
recommend an additional statistical review?
If an additional statistical review is recommended, please specify what aspects
require further assessment in your comments to the editors.
Not relevant to this manuscript
Quality of written English
Please indicate the quality of language in the manuscript:
Needs some language corrections before being published
Declaration of competing interests
Please complete a declaration of competing interests, considering the following
questions:
1
. 
Have you in the past five years received reimbursements, fees, funding, or
salary from an organisation that may in any way gain or lose financially
from the publication of this manuscript, either now or in the future?
2
. 
Do you hold any stocks or shares in an organisation that may in any way
gain or lose financially from the publication of this manuscript, either now
or in the future?
3
. 
Do you hold or are you currently applying for any patents relating to the
content of the manuscript?
4
. 
Have you received reimbursements, fees, funding, or salary from an
organization that holds or has applied for patents relating to the content of
the manuscript?
5
. 
Do you have any other financial competing interests?
6
. 
Do you have any non-financial competing interests in relation to this
paper?
If you can answer no to all of the above, write 'I declare that I have no competing
interests' below. If your reply is yes to any, please give details below.
'I declare that I have no competing interests'
I agree to the open peer review policy of the journal. I understand that my name
will be included on my report to the authors and, if the manuscript is accepted
for publication, my named report including any attachments I upload will be
posted on the website along with the authors' responses. I agree for my report to
be made available under an Open Access Creative Commons CC-BY license
(
http://creativecommons.org/licenses/by/4.0/
). I understand that any comments
which I do not wish to be included in my named report can be included as
confidential comments to the editors, which will not be published.
I agree to the open peer review policy of the journal
Reviewer’s report
Title: 
Overexpression of P-glycoprotein, MRP2, and CYP3A4 impairs intestinal
absorption of octreotide in rats with portal hypertension
Version: 
0 
Date: 
20 Jan 2019
Reviewer: 
Ying-Ying Yang
Reviewer's report:
comments to the BMGE-D-18-00745
Portal hypertension (PH) is the main cause of complications and death in liver
cirrhosis. Oral administration of octreotide (OCT), a drug that reduces PH by
constricting mesenteric arteries, is limited by marked intestinal first-pass
elimination. In this study, bile duct ligation (BDL) was used in rats to induce
liver cirrhosis with PH to examine the kinetics and molecular determinants of
intestinal absorption of OCT. Through both in situ and in vitro experiments in
jejunal segments, we observed that intestinal OCT absorption in both control and
PH rats is largely determined by Pglycoprotein (P-gp) and, to a lesser extent, by
multidrug resistance-associated protein 2 (MRP2). OCT transportation mediated
by P-gp and MRP2 was proved by Caco-2 cell experiment. The results of RT-
PCR, western blot, and immunohistochemical analyses suggested impaired
absorption of OCT in PH is determined in part by jejuna upregulation of these
two transporters. Using intestinal microsomes, we also found that cytochrome
P450 3A4 metabolizes OCT, and its upregulation in PH likely contributes to
impaired drug absorption. Thus inhibition of P-gp, MRP2, and CYP3A4 may
represent a valid option for decreasing intestinal first-pass effects on orally
administered OCT, thereby increasing its bioavailability to alleviate PH in
patients with cirrhosis. 
Major comments:
The rationales of study 
[1]. In the acute status of variceal bleeding, most patient need to be NPO. In
clinical practice, the intravenous infusion of octreotide needs to give through the
IV pump due to short half-life of octreotide. For chronic use of octreotide, there
is a long acting type of octreotide which call lantreotide. Accordingly, the
rationales to undergone this study need to be clarify.. 
[2].The standard treatment for long-term prophylaxis of the rupture of
esophageal varices is beta-blocker. So, the beta-blocker should be serves as
positive control. 
[3].The background description for mal-aborption of medicine in PH animals is
not clear. Specific references need to be provided. 
s text when adding your comments to the authors.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Unable to assess
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the
authors.
Unable to assess
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Unable to assess
Are you able to assess any statistics in the manuscript or would you
recommend an additional statistical review?
If an additional statistical review is recommended, please specify what aspects
require further assessment in your comments to the editors.
Not relevant to this manuscript
Quality of written English
Please indicate the quality of language in the manuscript:
Needs some language corrections before being published
Declaration of competing interests
Please complete a declaration of competing interests, considering the following
questions:
1
. 
Have you in the past five years received reimbursements, fees, funding, or
salary from an organisation that may in any way gain or lose financially
from the publication of this manuscript, either now or in the future?
2
. 
Do you hold any stocks or shares in an organisation that may in any way
gain or lose financially from the publication of this manuscript, either now
or in the future?
3
. 
Do you hold or are you currently applying for any patents relating to the
content of the manuscript?
4
. 
Have you received reimbursements, fees, funding, or salary from an
organization that holds or has applied for patents relating to the content of
the manuscript?
5
. 
Do you have any other financial competing interests?
6
. 
Do you have any non-financial competing interests in relation to this
paper?
If you can answer no to all of the above, write 'I declare that I have no competing
interests' below. If your reply is yes to any, please give details below.
'I declare that I have no competing interests'
I agree to the open peer review policy of the journal. I understand that my name
will be included on my report to the authors and, if the manuscript is accepted
for publication, my named report including any attachments I upload will be
posted on the website along with the authors' responses. I agree for my report to
be made available under an Open Access Creative Commons CC-BY license
(
http://creativecommons.org/licenses/by/4.0/
). I understand that any comments
which I do not wish to be included in my named report can be included as
confidential comments to the editors, which will not be published.
I agree to the open peer review policy of the journal
Please review this paper.
user
Reviewer’s report
Title: 
Overexpression of P-glycoprotein, MRP2, and CYP3A4 impairs intestinal
absorption of octreotide in rats with portal hypertension
Version: 
0 
Date: 
20 Jan 2019
Reviewer: 
Ying-Ying Yang
Reviewer's report:
comments to the BMGE-D-18-00745
Portal hypertension (PH) is the main cause of complications and death in liver
cirrhosis. Oral administration of octreotide (OCT), a drug that reduces PH by
constricting mesenteric arteries, is limited by marked intestinal first-pass
elimination. In this study, bile duct ligation (BDL) was used in rats to induce
liver cirrhosis with PH to examine the kinetics and molecular determinants of
intestinal absorption of OCT. Through both in situ and in vitro experiments in
jejunal segments, we observed that intestinal OCT absorption in both control and
PH rats is largely determined by Pglycoprotein (P-gp) and, to a lesser extent, by
multidrug resistance-associated protein 2 (MRP2). OCT transportation mediated
by P-gp and MRP2 was proved by Caco-2 cell experiment. The results of RT-
PCR, western blot, and immunohistochemical analyses suggested impaired
absorption of OCT in PH is determined in part by jejuna upregulation of these
two transporters. Using intestinal microsomes, we also found that cytochrome
P450 3A4 metabolizes OCT, and its upregulation in PH likely contributes to
impaired drug absorption. Thus inhibition of P-gp, MRP2, and CYP3A4 may
represent a valid option for decreasing intestinal first-pass effects on orally
administered OCT, thereby increasing its bioavailability to alleviate PH in
patients with cirrhosis. 
Major comments:
The rationales of study 
[1]. In the acute status of variceal bleeding, most patient need to be NPO. In
clinical practice, the intravenous infusion of octreotide needs to give through the
IV pump due to short half-life of octreotide. For chronic use of octreotide, there
is a long acting type of octreotide which call lantreotide. Accordingly, the
rationales to undergone this study need to be clarify.. 
[2].The standard treatment for long-term prophylaxis of the rupture of
esophageal varices is beta-blocker. So, the beta-blocker should be serves as
positive control. 
[3].The background description for mal-aborption of medicine in PH animals is
not clear. Specific references need to be provided. 
s text when adding your comments to the authors.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Unable to assess
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the
authors.
Unable to assess
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Unable to assess
Are you able to assess any statistics in the manuscript or would you
recommend an additional statistical review?
If an additional statistical review is recommended, please specify what aspects
require further assessment in your comments to the editors.
Not relevant to this manuscript
Quality of written English
Please indicate the quality of language in the manuscript:
Needs some language corrections before being published
Declaration of competing interests
Please complete a declaration of competing interests, considering the following
questions:
1
. 
Have you in the past five years received reimbursements, fees, funding, or
salary from an organisation that may in any way gain or lose financially
from the publication of this manuscript, either now or in the future?
2
. 
Do you hold any stocks or shares in an organisation that may in any way
gain or lose financially from the publication of this manuscript, either now
or in the future?
3
. 
Do you hold or are you currently applying for any patents relating to the
content of the manuscript?
4
. 
Have you received reimbursements, fees, funding, or salary from an
organization that holds or has applied for patents relating to the content of
the manuscript?
5
. 
Do you have any other financial competing interests?
6
. 
Do you have any non-financial competing interests in relation to this
paper?
If you can answer no to all of the above, write 'I declare that I have no competing
interests' below. If your reply is yes to any, please give details below.
'I declare that I have no competing interests'
I agree to the open peer review policy of the journal. I understand that my name
will be included on my report to the authors and, if the manuscript is accepted
for publication, my named report including any attachments I upload will be
posted on the website along with the authors' responses. I agree for my report to
be made available under an Open Access Creative Commons CC-BY license
(
http://creativecommons.org/licenses/by/4.0/
). I understand that any comments
which I do not wish to be included in my named report can be included as
confidential comments to the editors, which will not be published.
I agree to the open peer review policy of the journal
assistant