www.lesswrong.com/posts/MoF426vqQFmuwwnFf/bigger-livers
4 corrections found
a viral gene therapy in mice that induced follistatin overexpression in the liver resulted in 40% bigger livers, with no apparent signs of impaired liver function.
The cited follistatin gene-therapy study was done in adult rats, not mice. Its abstract says adenoviral follistatin enlarged the livers of adult male rats to 146% of control without significant dysfunction.
Full reasoning
The species is misstated here.
The cited paper is titled "Adenovirus-mediated overexpression of follistatin enlarges intact liver of adult rats". In the PubMed abstract, the authors write that intraperitoneal injection of the adenoviral vector caused significant liver growth "in intact liver of adult male rats" 12 days after treatment, without significant dysfunctions.
So the underlying result is about rats, not mice. The approximate size increase is in the same ballpark as the post says (the paper reports 146% of control, i.e. about a 46% increase), but the animal species in the post is incorrect.
1 source
- Adenovirus-mediated overexpression of follistatin enlarges intact liver of adult rats - PubMed
Intraperitoneal injection of AdexCAFS288 in vivo resulted in significant liver growth (146% of control) in intact liver of adult male rats 12 days following treatment without significant dysfunctions.
they also have liver cancers
The cited Yap/Taz knockout paper reported liver adenomas, not liver cancers. It explicitly says the mice did not have hepatocellular carcinoma or cholangiocarcinoma.
Full reasoning
This overstates what the cited mouse study found.
In the full text of Lu, Finegold, and Johnson (2018), the authors say that one-year-old Yap/Taz-mutant mice developed liver adenomas. They then immediately add: "We did not observe other liver tumors in these mice at 1 year of age, including hepatocellular carcinoma or cholangiocarcinoma."
That directly contradicts the wording "liver cancers". An adenoma is not the same thing as a carcinoma; NCBI's MedGen entry notes that adenomas are neoplasms whose vast majority are benign.
So the paper supports a claim that these mice developed adenomas/tumors, but not that they had liver cancers.
2 sources
- Hippo pathway coactivators Yap and Taz are required to coordinate mammalian liver regeneration - PMC
Unexpectedly, at 1 year of age yapΔ/tazΔ-mutant mice developed liver adenomas... We did not observe other liver tumors in these mice at 1 year of age, including hepatocellular carcinoma or cholangiocarcinoma.
- Adenoma (Concept Id: C0001430) - MedGen - NCBI
Definition ... The vast majority are benign. [from NCI]
obese people don’t have bigger livers or kidneys.
This is too categorical: human studies do report larger kidneys in obesity, and studies also report larger liver volumes in obese patients. So big livers/kidneys are not unique to athletes.
Full reasoning
The claim says obese people do not have bigger livers or kidneys, but published human studies report the opposite.
For kidneys, a CT study in potential live kidney donors found that increased body mass index was associated with increased total kidney volume. The association persisted after adjustment for age, sex, race, hypertension, and diabetes.
For livers, human studies also report larger liver volume in obese patients. In one study of patients undergoing liver resection, obese patients had a trend toward larger liver size and the authors concluded that "obese patients had larger ... livers." Another study comparing NAFLD patients with healthy controls found significantly larger livers in the patient group and identified BMI as an independent predictor of liver size.
These studies do not imply that every obese person will have enlarged organs, but they do contradict the post's blanket statement that obese people don't have bigger livers or kidneys.
3 sources
- The Effect of Obesity on Kidney Volume in Living Kidney Donors - PMC
Obesity and overweight were associated with larger total kidney volume in otherwise healthy adults. Higher body mass index and obesity remained significantly associated with larger total kidney volume after controlling for covariates.
- Sarcopenia, obesity and sarcopenic obesity: effects on liver function and volume in patients scheduled for major liver resection - PubMed
Obese patients showed significantly reduced liver function ... and a trend towards larger liver size ... compared with non-obese patients... obese patients had larger, although less functional, livers.
- Comparison of size of the liver between patients with non-alcoholic fatty liver disease and healthy controls - PMC
In comparison to controls, NAFLD patients had considerably larger livers on average... BMI ... [was an] independent variable[] for predicting the liver size.
IL-6 will make a rat’s liver double in size
The cited IL-6 hepatomegaly paper was done in mice, not rats. Its title and abstract both describe systemic IL-6 administration causing liver enlargement in nude mice.
Full reasoning
The animal species is wrong here.
The cited study is "Massive liver growth in mice induced by systemic interleukin 6 administration". Its abstract states that systemic IL-6 administration in nude mice caused dramatic hepatomegaly, with liver mass increasing to 2 to 3 times normal.
So the underlying finding is about mice, not rats.
1 source
- Massive liver growth in mice induced by systemic interleukin 6 administration - PubMed
Here, we show that systemic administration of IL-6 using CHO cell tumors in nude mice results in dramatic hepatomegaly... Liver mass and liver to body mass ratios increased to 2 to 3 times normal.