Only 24.7% of mouse heart studies reported the pressure they applied

TAC is a surgical model that narrows a mouse aorta to put the heart under pressure overload. Because it reproduces thickening and eventual functional decline within weeks, it works as a standard for heart failure research. The catch is that how much narrowing was applied varies between labs. This systematic review gathered 89 papers containing new TAC experiments published between January 2023 and December 2024 across six leading cardiovascular journals, and counted how often the items that decide reproducibility and translational relevance were actually reported.

What was missing?

• Pressure gradient reported: 24.7% — one paper in four stated the size of the load at all. Reported values spanned 36.8 to 131 mmHg.
• Outliers excluded: 7.9% — fewer than one in ten screened out animals where the surgery landed far too tight or too loose.
• Early cardiac function measured: 20.2% — one paper in five established the starting point before intervening.
• Intervention started at least 7 days post-surgery: 31.5% — dosing immediately after surgery blends the acute injury response with the treatment effect.
• Female mice included: 28.1% — inclusion was higher among NIH-funded papers.

The first item carries the rest. 36.8 mmHg and 131 mmHg are not the same experiment. Without a reported gradient there is no way to separate a drug effect from a surgery that simply bit harder. Add unscreened outliers and no baseline function, and what remains is data showing that a difference occurred, with no way to say where it came from. The authors land in the same place: routine gradient measurement, early function assessment, delayed intervention timing, and inclusion of female mice should be standard.

Why should a lifter care?

Because a large share of the research quoted in fitness content is animal or cell work. Follow "this compound prevents muscle loss" or "this ingredient burns fat" back to the source and you usually arrive at a dish or a rodent. What matters there is not the conclusion but whether the conditions were controlled — the same question we put to a cell study that cannot be converted into a human dose and to a fat-browning experiment in cells.

The 28.1% figure for female inclusion is not a footnote either. The same skew repeats in training research, which means "studies show" is often an extrapolation from male data when a woman reads it. And the spread between individuals is real to begin with — the same program produces different results. In the end the most reliable dataset is the one from your own body, which is what the numbers you put into the calculator are for.