The NIH says investigators must incorporate sex-differences analyses in their studies

For some reason I am having a DOI error on the actual comment from Clayton and Collins. So until that is resolved, the sourcing is from the journalists who got the embargoed version.

Apparently Janine Clayton and Francis Collins have issued a commentary on a new policy that the NYT describes as:

The N.I.H. is directing scientists to perform their experiments with both female and male animals and include both sexes in sufficient numbers to see statistically significant differences. Grant reviewers will be instructed to take the sex balance of each study design into account when awarding grants.

Yeah, that sounds pretty clear. My studies just doubled…which means really that they were just cut in half. I’m cool with that. I actually agree that it would be good if we did almost everything as a sex-differences study.

There’s the money though. Sex difference studies in a behaving animal are not just a doubling as it happens (and as I inaccurately described it just above). From a prior post on this topic entitled: The funding is the science II, “Why do they always drop the females?”

As nicely detailed in Isis’ post, the inclusion of a sex comparison doubles the groups right off the bat but even more to the point, it requires the inclusion of various hormonal cycling considerations. This can be as simple as requiring female subjects to be assessed at multiple points of an estrous cycle. It can be considerably more complicated, often requiring gonadectomy (at various developmental timepoints) and hormonal replacement (with dose-response designs, please) including all of the appropriate control groups / observations. Novel hormonal antagonists? Whoops, the model is not “well established” and needs to be “compared to the standard gonadectomy models”, LOL >sigh<.

The money and the progress.

Keep in mind, if you will, that there is always a more fundamental comparison or question at the root of the project, such as “does this drug compound ameliorate cocaine addiction?” So all the gender comparisons, designs and groups need to be multiplied against the cocaine addiction/treatment conditions. Suppose it is one of those cocaine models that requires a month or more of training per group? Who is going to run all those animals ? How many operant boxes / hours are available? and at what cost?

Oh, don’t worry bench jockeys. According to the NYT article:

Researchers who work with cell cultures are also being encouraged to study cells derived from females as well as males, and to do separate analyses to tease out sex differences at the cellular level.

“Every cell has a sex,” Dr. Clayton said in a telephone interview. “Each cell is either male or female, and that genetic difference results in different biochemical processes within those cells.”

“If you don’t know that and put all of the cells together, you’re missing out, and you may also be misinterpreting your data,” Dr. Clayton added. For example, researchers recently discovered that neurons cultured from males are more susceptible to death from starvation than those from females, because differences in the ways their cells process nutrients.

“Encouraged”. Okay, maybe you CultureClowns have an escape clause here. Animal model folks are facing “demanded” language.

Final observations are ridiculous:

But [the new policies] are likely to be met with resistance from scientists who fear increased costs and difficulty in performing their experiments. Studying animals of both sexes may potentially double the number required in order to get significant results.

“There’s incredible inertia among people when it comes to change, and the vast majority of people doing biological research are going to think this is a huge inconvenience,” Dr. Zucker said.

…

Margaret McCarthy, a neuroscientist at University of Maryland School of Medicine who studies sex differences, agreed. “The reactions will range from hostile — ‘You can’t make me do that’ — to ‘Oh, I don’t want to control for the estrous cycle,’” she said.

This has nothing to do with whether a scientist “wants” to or not.

Let me be clear, I want to do sex-differences studies. I am delighted that this will be a new prescription. I agree with the motivating sentiments.

What I “fear” is that grant applications will be kicked in the teeth if they include sex differences comparisons. What I “fear” is that my research programs will be even less productive on the main area of interest, to the tune of a lot of extra work that will simply confirm a lot of what we already know. For example, female rats tend to self-administer more drug than males do. A lot of my colleagues have been working on these topics for a long time. The identification of those areas where it actually matters (i.e., sex difference effects that haven’t yet been detected) are going to come along with a lot of negative findings. What I “fear” is that when we are interested in a certain thing, there is a bit of sex-differences literature and the hypothesis is going to be “males and females are the same” or even “females are more/less sensitive to drug” that this is going to bring down the holy hells of reviewer wrath over what hypothesis we are testing.

I fear a lot of things about this. What I don’t fear is my own interest in the topic. What I don’t fear is the “inconvenience”. I don’t even fear “difficulty”. It just isn’t that difficult to add female groups to my studies.

What it takes is additional grant funding. Or tolerance on the part of P&T committees, hiring committees and grant review panels for apparently reduced progress on a scientific topic of interest. And those things are not at all easy to come by.

The funny thing is, we’ve been taking steps in the lab toward this direction in the past year anyway. So I should be grateful I have at least that little tiny bit of a head start on this stuff.