Review for 10.1186/1471-230X-14-66 (2014)

Reviewer's report
Title:High mobility group B1 mediates gut bacterial translocation in
acetaminophen hepatotoxicity
Version: 1Date:28 August 2013
Reviewer: Daniel J Antoine
Reviewer's report:
This interesting manuscript by Yang and colleagues seeks to investigate the
concept that HMGB1 released during hepatic injury following toxic APAP
treatment is critical for bacterial translocation and regulates survival in mice.
Overall, the manuscript is interesting but several conceptual, technical and
grammatical points need to be addressed.
Major Compulsory revisions:
The currently presented findings of the impact of HMGB1 neutralization on
regeneration are interesting but the concept is not novel. It is already known that
APAP will induce HMGB1 release in mice and in the clinic during overdose and
that HMGB1 mediates BT in a variety of models. Furthermore, this group has
previously published data to support this (Yang R et al. BMC Gasteroenterol
2012). The current data appear to be largely a replication of this work and add
little new mechanistic understanding by how BT during APAP-induced
hepatotoxicity regulates survival.
Currently, the data presented do not definitively prove that HMGB1 mediated gut
BT during APAP hepatotoxicity. The title of the current work should be altered to
reflect the current data presented to something like ‘HMGB1 neutralization is
associated with bacterial translocation during APAP hepatotoxicity’. Or, further
mechanistic work should be carried out. For example, does the addition of
rHMGB1 have the opposite effect of neutralization? What impact does Box A or
Box B have? Do HMGB1 post-translational modifications impact on BT during
APAP hepatotoxicity – recently published data suggest that HMGB1 function is
redox dependent and different functional redox isoforms have been identified in
serum following APAP treatment to mice
Neutralisation of HMGB1 and the impact on APAP hepatotoxicity has been
previously reported by a number of independent research groups. These reports
should be cited and discussed in the context of the current work.
Published data consistently show that the inhibition of HMGB1 via neutralizing
antibodies modulates overall injury following APAP treatment to mice to a much
lower degree that that seen here. This discrepancy should be discussed.
The authors should present a complete data set to include all the relevant control
animals for example, what is the impact on BT in mice treated with anti-HMGB1
or sham antibodies only?
The hepatotoxic effects of APAP are dependent upon reactive metabolite
formation. The author’s present GSH depletion data suggesting that APAP
reactive metabolite formation is not blocked by antibody treatment. However, this
is an indirect measure of APAP reactive metabolite formation and should be
further assessed through hepatic covalent binding studies or APAP metabolic
profiling. What impact does a CYP450 inhibitor have on the overall consequence
of BT translocation during APAP treatment?
The glutathione data are not at the time point indicated in the methods section.
The hepatic glutathione could not be determined at 6hr as the mice were only
killed at 24 and 48hr. This should be rectified or discussed.
There should be an explanation and discussion offered as to why the PCNA
staining does not correspond with the HE staining
Minor Essential revisions:
It is not clear which data have been analysed by t-test and which by ANOVA
The final paragraph of the discussion and the conclusion suggest pathological
outcomes of bacterial translocation, but references are required to support these
statements.
The authors should justify why cytokine mRNA has been used as readout of
cytokine level as opposed to serum quantification
Figure 7 has no legend, no title and no explanation for what it shows. The figure
should be removed or explained.
The grammar, spelling and sentence structure throughout the article in general
should be improved throughout
Figure legends should state the statistical tests used when giving p values
Axis labels should be consistent in their font, size and decimal places and could
label time-points and treatment group separately. Additional formatting
requirements include; Fig.1 should use decimal points rather than commas on
the y-axis, Figure.3 should use decimal points rather than commas on the y-axis,
The same number of decimal places should be used for all y-axis values on
figure.3, The x-axis labelling on Figures. 1, 2,3 and 5 should be made clearer by
separating the time from the antibody treatment, the font style for figures 5 and 6
is different to that used in figures 2 and 4.
Inconsistencies with abbreviations should be corrected throughout manuscript.
For example, The abbreviation KHBB is not defined in the “Intestinal Mucosal
Permeability” section
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Needs some language corrections before being
published
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
No financial competing interest to declare. However, I have a published track
recorded in the understanding of HMGB1 biology, its role in drug-induced toxicity
and as a biomarker. I have identified and published reports related to functional
specific isoforms of HMGB1 and have developed bioanalytical technologies for
their quantification. I currently have applied for a patent involving HMGB1 and
structurally related isoforms as a biomarker of drug-induced liver injury.