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Comment by j_bum | Hacker News Reader

In mice [0]

What translational value was gained from this study? This is lost on me.

We take germ-free pregnant female mice, with no gut microbiome. We then add B. breve UCC2003 to the experimental group. We observe that the metabolic profiles of the fetal brains from the experimental group are altered relative to the controls.

Great. Now we can say, with slightly more confidence, “A fetus in a pregnant biological female human with only B. breve UCC2003 in their gut microbiome may exhibit altered brain metabolic profiles.” Did we need to euthanize 11 pregnant mice (at least) to determine this?

I commend the authors on their reporting and transparency, but truly I do not understand this study.

Clearly I am cynical from my time in academic biomedical research, so perhaps my perception of this study is biased. Happy to hear opposing opinions.

[0] https://x.com/justsaysinmice

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Well perhaps you could try reading the paper and drawing from the author’s words about their intentions? It’s very clear.

1) a significant problem for humans is the placenta doesn’t grow enough which makes the babies not get enough nutrients

2) this specific genus of gut bacteria is supposed to become common in pregnant women And mice

3) they took pregnant mice that were specifically lacking this bacteria and tested if reintroducing it would have positive effects, and it did.

4) a couple direct quotes > Additionally, our approach could potentially align with supplementation studies in pregnant women, as we started the experiments after pregnancy was confirmed.

> Our results have potential translational implications, as around 14% of pregnant women use probiotics during pregnancy in European countries like the Netherlands [ 62 ]. However, the utilization of probiotics in clinical and nutritional contexts, particularly during pregnancy, remains a topic of continual debate. Thus, to comprehensively understand their influence on the developing offspring, it is essential to define the mechanisms supporting their beneficial effects.

Biomed academia is a shitshow but your effort here seems particularly bad faith and lame

Well, I read the intro, results, and methods prior to making my comment. Have you read the limitations?

1. & 2. Great. I agree. How does this research address those needs?

3. No, they didn’t. They took germ free mice without a gut microbiome and added probiotics with vs. without colonies of the supplemental bacteria. In my opinion, this bludgeons away translational value. They did no compositional analysis either via RNA seq, likely due to a lack of funding.

4. The authors can say lots about what their study could mean. Authors say lots of things all of the time. I, and anecdotally many others, put very little into author over-interpretation of data. The data can speak for themselves.

Frankly I’m not sure how my critique of this research is bad faith. Lame? Maybe, I’m not to judge that.

But I appreciate the discussion.

> Did we need to euthanize 11 pregnant mice (at least) to determine this?

FYI we slaughter more than a trillion animals per year for food, I'm all for reducing animal suffering but we have many many many things to focus on before lab mice

I guess over a hundred per person per year is plausible. Seems high though.

Fish makes the bulk of it, for land animal it's 100b+

I am unfortunately aware, as I work in the biomedical research field. We can still focus on reducing needless animal death concurrently to other issues.

Some day in the future we will create some very powerful mutant mice that will take up the torch after the Age of Man has passed.

> In mice [0]

This is anti-science Wokism. The idea people are not mammals, people are defined by the identity rules the Woke control, not evolution.

There was no reason to say in mice with this thread.

> Did we need to euthanize 11 pregnant mice (at least) to determine this?

You want to do this on aborted human fetuses with a random control? What are you talking about? Do you only want experiments that jump straight to curing cancer in humans with FDA approval?

This is called science, you do experiments to find parts of the puzzle.

You seem to be making some point that 11 dead mice lives matter, when I drowned that many so they wouldn't eat $10 worth of livestock feed.

The HN article might be blogspam but it links to the research and it's open, do better - https://www.sciencedirect.com/science/article/pii/S221287782...

Not everything needs to be about politics, some people actually talk about science when they talk about science.

Yes, humans are mammals, but not all mammals are the same, so the things that are true for one species are not necessarily true for other species. More precisely, when you measure some effects, it's not just about "true or false" but also about "how much".

For example, imagine learning that some magical pill makes a human life longer, with zero side effects. Before you start celebrating, you ask "how much longer?"... and you learn that the answer is 5 seconds. So, the statement is still technically true, but what seemed like a good news became quite useless.

Mice are different from humans. They are smaller, they live shorter. As a consequence, some interventions that cause big changes in mice, cause technically nonzero but actually very small changes in humans. So small that the difference from zero is negligible for all practical purposes.

There is a lot of fascinating research that can make life much better and longer... for mice... but has almost no effect on humans. This is why "in mice" became a meme, because quite often research is reported in a way that makes readers think it applies to humans, when if fact it only applies to mice (or it is yet unknown whether the effects on mice will also be confirmed with humans).

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