Reviewer's report
Title:Transporter function and cyclic AMP turnover in normal colonic mucosa
from patients with and without colorectal neoplasia
Version: 1Date:9 February 2012
Reviewer: Theresia Thalhammer
Reviewer's report:
The study is an important contribution in the field of physiology/pathophysiology
of cyclic nucleotide transport in colon.
Studies were done on biopsies from patients with and without neoplasia (CRN).
By measuring electrogenic ion transport parameters in a Using chamber, the
authors demonstrate transport of cAMP. Together with data on the expression of
influx and efflux transporters (known to transport cAMP and prostaglandins), they
propose a model for the turnover of cAMP in different colon cell types.
The findings are important to understand cAMP turnover in the colon.
- The methods are appropriate, the concept explained in the Discussion is
pausibel, and it is based on the data given.
- However, there are number of open questions, but to answer them, would
require extenisive investigations. This is beyond the scope of the study and
would be better done in a subsequent study in appropriate cell lines.
(also with respec to the limited amount of material obtained by biopsies).
However, other major points must be clarified before publication.
Major points:
1. By immunohistochemistry, the authors show that OATP1C1, OATP2B1,
OATP4A1, and OATP4C1 as well as ABC transporters (ABCC5, ABCC4 and
ABCC3 are located in different colon cell types.
Double immunofluorecence staining of transporters with cell specific marker (e.g
chromogranin for endocrine cells, cytokeratin 7 for goblet cells) would allow a
valid identification of these cell types in selected samples. It would also help to
dicriminate between similar appearing cell types, e.g. endocrine cells vs. B-cells.
This is important, because OATP2B1 immunoreactivity restricted to endocrine
cells has not been observed so far.
2. Question: Is the localization of transports different in normal vs. CRN samples.
Do the PCR data relate to the staining intensity?
3. Results: probing the excretory system … the description OATP4C1 function (
Fig. 5D).. the authors should discuss that it OATP4C1 is regarded as a “kidney
specific” transporter implicated in the removal of uremic toxins, drugs etc.
(Toyohara et al. 2009)
4. No explanation for OATP1C1, known as thyroid transporter, is given.
.
Minor points:
1. Results, paragraph: Cox enzymes… second paragraph…….. higher levels of
OATP4A1 in colon cancer were first shown by Ancona et al. (add citation)
2. Conclusion:
3rd line. ABCC4 in the periphery of Goblet cells ?
3. Figures:
The same magnification should be applied in all images. Details could be shown
as Inserts. Show negative controls (non-immunogenic IgG staining).
Level of interest: An article of outstanding merit and interest in its field
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Reviewer's report
Title:Transporter function and cyclic AMP turnover in normal colonic mucosa
from patients with and without colorectal neoplasia
Version: 1Date:9 February 2012
Reviewer: Theresia Thalhammer
Reviewer's report:
The study is an important contribution in the field of physiology/pathophysiology
of cyclic nucleotide transport in colon.
Studies were done on biopsies from patients with and without neoplasia (CRN).
By measuring electrogenic ion transport parameters in a Using chamber, the
authors demonstrate transport of cAMP. Together with data on the expression of
influx and efflux transporters (known to transport cAMP and prostaglandins), they
propose a model for the turnover of cAMP in different colon cell types.
The findings are important to understand cAMP turnover in the colon.
- The methods are appropriate, the concept explained in the Discussion is
pausibel, and it is based on the data given.
- However, there are number of open questions, but to answer them, would
require extenisive investigations. This is beyond the scope of the study and
would be better done in a subsequent study in appropriate cell lines.
(also with respec to the limited amount of material obtained by biopsies).
However, other major points must be clarified before publication.
Major points:
1. By immunohistochemistry, the authors show that OATP1C1, OATP2B1,
OATP4A1, and OATP4C1 as well as ABC transporters (ABCC5, ABCC4 and
ABCC3 are located in different colon cell types.
Double immunofluorecence staining of transporters with cell specific marker (e.g
chromogranin for endocrine cells, cytokeratin 7 for goblet cells) would allow a
valid identification of these cell types in selected samples. It would also help to
dicriminate between similar appearing cell types, e.g. endocrine cells vs. B-cells.
This is important, because OATP2B1 immunoreactivity restricted to endocrine
cells has not been observed so far.
2. Question: Is the localization of transports different in normal vs. CRN samples.
Do the PCR data relate to the staining intensity?
3. Results: probing the excretory system … the description OATP4C1 function (
Fig. 5D).. the authors should discuss that it OATP4C1 is regarded as a “kidney
specific” transporter implicated in the removal of uremic toxins, drugs etc.
(Toyohara et al. 2009)
4. No explanation for OATP1C1, known as thyroid transporter, is given.
.
Minor points:
1. Results, paragraph: Cox enzymes… second paragraph…….. higher levels of
OATP4A1 in colon cancer were first shown by Ancona et al. (add citation)
2. Conclusion:
3rd line. ABCC4 in the periphery of Goblet cells ?
3. Figures:
The same magnification should be applied in all images. Details could be shown
as Inserts. Show negative controls (non-immunogenic IgG staining).
Level of interest: An article of outstanding merit and interest in its field
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Please review this paper.
user
Reviewer's report
Title:Transporter function and cyclic AMP turnover in normal colonic mucosa
from patients with and without colorectal neoplasia
Version: 1Date:9 February 2012
Reviewer: Theresia Thalhammer
Reviewer's report:
The study is an important contribution in the field of physiology/pathophysiology
of cyclic nucleotide transport in colon.
Studies were done on biopsies from patients with and without neoplasia (CRN).
By measuring electrogenic ion transport parameters in a Using chamber, the
authors demonstrate transport of cAMP. Together with data on the expression of
influx and efflux transporters (known to transport cAMP and prostaglandins), they
propose a model for the turnover of cAMP in different colon cell types.
The findings are important to understand cAMP turnover in the colon.
- The methods are appropriate, the concept explained in the Discussion is
pausibel, and it is based on the data given.
- However, there are number of open questions, but to answer them, would
require extenisive investigations. This is beyond the scope of the study and
would be better done in a subsequent study in appropriate cell lines.
(also with respec to the limited amount of material obtained by biopsies).
However, other major points must be clarified before publication.
Major points:
1. By immunohistochemistry, the authors show that OATP1C1, OATP2B1,
OATP4A1, and OATP4C1 as well as ABC transporters (ABCC5, ABCC4 and
ABCC3 are located in different colon cell types.
Double immunofluorecence staining of transporters with cell specific marker (e.g
chromogranin for endocrine cells, cytokeratin 7 for goblet cells) would allow a
valid identification of these cell types in selected samples. It would also help to
dicriminate between similar appearing cell types, e.g. endocrine cells vs. B-cells.
This is important, because OATP2B1 immunoreactivity restricted to endocrine
cells has not been observed so far.
2. Question: Is the localization of transports different in normal vs. CRN samples.
Do the PCR data relate to the staining intensity?
3. Results: probing the excretory system … the description OATP4C1 function (
Fig. 5D).. the authors should discuss that it OATP4C1 is regarded as a “kidney
specific” transporter implicated in the removal of uremic toxins, drugs etc.
(Toyohara et al. 2009)
4. No explanation for OATP1C1, known as thyroid transporter, is given.
.
Minor points:
1. Results, paragraph: Cox enzymes… second paragraph…….. higher levels of
OATP4A1 in colon cancer were first shown by Ancona et al. (add citation)
2. Conclusion:
3rd line. ABCC4 in the periphery of Goblet cells ?
3. Figures:
The same magnification should be applied in all images. Details could be shown
as Inserts. Show negative controls (non-immunogenic IgG staining).
Level of interest: An article of outstanding merit and interest in its field
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
assistant