Title: Gut Microbiome in Patients with Early-Stage and Late-Stage Endometriosis
Version: 2 Date: 19 Jun 2024
Reviewer's report:
The aim of this study was to compare the gut microbiota profiles between early and late stage
endometriosis in a cohort of Chinese patients. The authors also attempted to corelate any changes
with presence of dysmenorrhea. The area is one which has received increasing attention in recent
years yet many questions remain since most prior studies have examined differences between
patients and controls. As such this study is novel in attempting to elucidate the differences that
might occur depending on disease presentation. They concluded that the microbiota in late-
stage patients with dysmenorrhea has a distinct profile from either early stage or those with no
dysmenorrhea. When comparing early and late regardless of dysmenorrhea ten microbes were
consistently enriched, of which 4 correlated with disease severity. The possibility that changes in
the microbiota can be linked to mechanisms responsible for the pain in this condition is exciting,
however a short coming of the paper is that although the results were categorized into presence
and absence of dysmenorrhea there is no detailed explanation of how this was categorized.
Specifics
Abstract – needs some English editing
Introduction
Line 66 – include ref
It would be beneficial to include a hypothesis as to the results the authors expected and why,
in addition to the two aims stated.
Materials and methods
Line 124 – there needs to be clarification on the time period of enrollment which as written
could be between 12 and 14 months. Please include a defined date range eg June 1 2021 to July
31, 2022. Clarify also on Figure 1. It is also not clear how seasonal and dietary impacts were
minimized as mentioned in the abstract since this is not described at all.
Line 132  - it is not clear when the diagnosis of pelvic endometriosis was confirmed – was this
prior to enrolling in the study or during the study?
No exclusion criteria for other things that interact with the nicroflora????
Line 140 – it would be helpful if some examples of ‘incomplete date’ were included. It appears
that 37 subjects were excluded due to incomplete data (fig. 1) but it is not clear how many
excluded due to the sequencing results not passing quality control (line 141 – not shown in
figure 1)
Line 156 – it is implied that all of the fecal samples were analyzed at the same time (‘after 1
year of enrollment’) please rewrite to clarify if this is the case.
Results
Line 167 – clarify time period ie months- 12 or 14?
Line 190 – it is not clear why there was further evaluation on the inclusion criteria after collecting
samples since it would seem that these should have been screened beforehand aside from point
6 for diagnosis.
Line 205 – it is not clear over what time period the patients had preoperative dysmenorrhea.
Please also explain further the criteria for this designation, eg was it always, intermittently, mild,
severe, incapacitating….
Figure 3A & B panel very difficult to read at 100%. Can these be magnified somehow? The
labelling needs better explanation in the legend – what does F or T mean?
Line 244 – as written appears to contradict the prior sentence and is confusing – the prior sentence
seems to need correction since no intersectionality would imply a difference.
Figure 4 – what does EMs mean? Again clarify in legend the nomenclature for the positive/
negative for dysmenorrhea
Figure 5 – please clarify in legend what T and F represent. For the predictions are there any
differences between the groups? In each case they look very similar which would imply they
don’t play a significant role in any differences between early/late/+/- dysmenorrhea
Line 288 – ‘based on the above results’ – please clarify further which results you are referring to.
Figure 6 – legend needs correction for panels A and B as says comparing early and early.