Table 18

PFHxS (potassium salt)

CAS no. Not given

99.98%.

Bijland et al. (2011)

APOE*3-Leiden.CETP mice.

Male,

6-8/dose.

0 or 0.006% in diet equivalent to 6.

Diet (vehicle).

Diet,

4-6 weeks,

OECD 407,

GLP not stated.

At 6 mg/kg bw/day at 4-6 weeks (mean ± SD)

Serum: 188.3-217.6 ± 10.4-31.5.

Males:

↓ plasma TG: data only reported in figures.

↓ free cholesterol: data only reported in figures.

↓ non HDL cholesterol: data only reported in figures.

↓ HDL cholesterol: data only reported in figures.

↑ liver weight: data only reported in figures.

↑ hepatic TG: data only reported in figures.

↓ plasma TG: data only reported in figures.

↓ bile acid excretion: data only reported in figures.

Altered gene expression related to transcription factors, lipolysis, FA uptake and transport, FA binding and activation, FA oxidation, FA/TG synthesis, VLDL assembly, cholesterol synthesis, storage, metabolism and excretion, HDL formation, maturation, remodeling and uptake.

Recovery not assessed.

Males:

NA / 6*

The potency of PFAS to affect lipoprotein metabolism increased with increasing alkyl chain length.

The data suggest that PFHxS reduces plasma TG and total cholesterol mainly by impairing lipoprotein production.

K2

This study investigated the mechanism underlying the effect of PFAS surfactants on lipoprotein metabolism.

Only two dose groups were used i.e., control and single treatment group and only male animals were used.

The study was funded by the Nutrigenomics Consortium/Top Institute Food and Nutrition; the Netherlands Genomics Initiative; the Netherlands Organization for Health Care Research Medical Sciences); the Netherlands Organization for Scientific Research; the Netherlands Heart Foundation.

Authors are affiliated to 3M company.

PFHxS

(potassium salt)

CAS no. Not given

99.98%.

Butenhoff et al. (2009)

Crl:CD®(SD)

IGS BR VAF/Plus® rats.

Male

15 /dose.

0, 0.3, 1, 3 or 10.

Gavage,

Carboxymethylcellulose

42 days,

OECD 422,

GLP not stated.

At 0.3 mg/kg bw/day in F0 males on day 42 (mean ± SE).

Serum: 44.22 ± 12.66

Liver: 43.80 ± 8.07.

Males (mean ± SE):

↓ cholesterol (mg/dL): 57 ± 8 vs 41 ± 11.

Recovery not assessed.

Males:

NA / 0.3

Decreased serum total

cholesterol observed,

occurring at all dose levels. Although not reaching statistical significance until 10 mg/kg bw/day, mean serum triglycerides were

also lower in all treated groups relative to controls. This observation is consistent with cholesterol reduction as a sensitive clinical endpoint for response to the PFHxS

congener, PFOS.

K1

This study investigated potential toxicity of PFHxS on the reproduction and development in male and female SD rats.

Only male animals were used for repeated dosing segment of the OECD 422 study.

While this is a repeat dose with reproductive/developmental toxicity study, results are presented here as they relate to effects (in males only).

The authors are employees of the 3M Company, a former manufacturer of K+PFHxS. 3M supported the work.

PFHxS

(potassium salt)

CAS no. Not given

98.9%.

Chang et al. (2018)

Crl:CD1 mice.

Male

30/dose.

0, 0.3, 1, and 3

Gavage.

0.5% Tween20,

42 days,

OECD 422,

GLP study.

At 0.3 mg/kg bw/day (mean ± SD):

Liver: 25.9 ± 3.5.

Males (mean ± SD):

 ↑ centrilobular hypertrophy: 0 vs 8^#.

Recovery not assessed.

Males:

NA / 0.3

The liver has been identified as a target organ after repeated oral exposures to K+PFHxS. This observation is consistent with prior studies when rodents were exposed to other perfluoroalkyl acids such as PFHxS, PFOS, PFOA, PFNA, and PFDA and, also, in monkeys when treated with PFOS and PFOA.

The increased liver weights and centrilobular hypertrophy can be attributed, in part, to the activation of these specific xenosensor nuclear receptors.

Liver hypertrophy does not necessarily represent liver toxicity, nor is it necessarily a precursor to a particular manifestation of toxicity.

K1

This study investigated the toxicity of PFHxS in CD1 mouse development and reproduction.

Only male animals were used for repeated dosing segment of the OECD 422 study.

While this is a repeat dose with reproductive/developmental toxicity study, results are presented here as they relate to effects (in males only).

Liver mRNA transcripts were only measured at 0 and 3 mg/kg bw/day.

# Histopathology measured in 10/dose.

The authors are current or former employees or consultants of 3M Company, a former manufacturer of PFHxS and the company supporting the work reported on in the article. Authors received an unrestricted gift grant from 3M Company.

PFHxS

(potassium salt)

CAS no. Not given

97%.

Das et al. (2017)

SV129 and PPAR alpha null mice.

Male

4/dose.

0 or 10.

Gavage,

Vehicle not given,

7 days,

Non-GL study,

GLP not stated.

NR

Wild type males (mean ± SE):

↑ relative liver weight: data only reported in figures.

↑ absolute liver weight: data only reported in figures.

↑ liver cell size: data only reported in figures.

↓ DNA content: data only reported in figures.

↑ lipid and TGs in liver: data only reported in figures.

Recovery not assessed.

Males:

NA / 10

Increases in relative and absolute liver weight were seen in wild type and PPARα-null mice.

The increased cell size and decreased DNA content indicate hepatocyte hypertrophy.

K2

This study investigated the effects of perfluoroalkyl-acids on lipid metabolism using male SV129 and PPAR alpha null mice.

Only data for wild type mice are presented.

Only two dose groups were used i.e., control and single treatment group and only male animals were used.

The study was funded by the U.S. Environmental Protection Agency. Reviewed by the National Health and Environmental Effects Research Laboratory and approved for publication. The 3M Company also funded part of the work.

PFHxS

(potassium salt)

CAS no. Not given

98%.

He et al. (2022)

C57BL/6 mice (high fat diet).

Male

10/dose.

0 or 450 µg/l in drinking water equivalent to 60-110.

Drinking water,

Water,

12 weeks,

Non-GL study,

GLP not stated.

NR

Males (mean ± SE):

↑ body weight from week 7: data only reported in figures.

↑ ALT (U/L): 30.812 ± 3.503 vs 43.633 ± 3.568.

↑ LDL-C (mml/L): 2.368 ± 0.089 vs 2.807 ± 0.067.

↑ TG: data only reported in figures.

↑ expression of genes relating to lipid metabolism, inflammation, and fibrosis.

Recovery not assessed.

Males:

NA / 60*

Treatment markedly aggravated hepatic symptoms resembling NAFLD and caused systematic metabolic disorders as well as gut dysbiosis in the obese mice. Key genes of hepatic lipid metabolism, inflammation, and fibrosis were strongly altered.

The data suggest that environmental PFHxS exposure is a tangible risk factor for metabolic diseases such as NAFLD, especially among obese individuals.

K2

The aim of the study was to investigate the effect of low-dose (environmental) exposure on male mice given a high fat diet.

Only two dose groups were used i.e., control and single treatment group and only male animals were used.

This study was funded by the National Natural Science Foundation of China and the Excellent Research Program of Nanjing University.

PFHxS potassium salt

CAS no. 3871-99-6

>98%.

NTP. (2022a)

Sprague-Dawley rats.

Male and female.

10/sex/dose.

0, 0.625, 1.25, 2.5, 5 or 10 (males)

0, 3.12, 6.25, 12.5, 25 or 50 (females).

Gavage,

2% Tween® 80,

28 days.

NTP protocol.

GLP study (FDA GLP Regs).

At 0.625 mg/kg bw/day in males (mean ± SE)

Plasma: 66.76 ± 3.518.

At 1.25 mg/kg bw/day in males.

Plasma: 92.08 ± 3.348.

At 3.12 mg/kg bw/day in females.

Plasma: 37.030 ± 1.651.

Males (mean ± SE):

↑ absolute liver weight (g): 11.36 ± 0.32 vs 12.58 ± 0.25.

↑ relative liver weight (mg/g body weight): 33.77 ± 0.36 vs 36.81 ± 0.39.

↓ cholesterol (mg/dL): 109 ± 4 vs 96 ± 3.

↑ gene expression of Cyp4a1: 1.08 ± 0.14 vs 2.29 ± 0.26.

↑ gene expression of Cyp2b1: 1.10 ± 0.15 vs 3.97 ± 1.08.

↑ gene expression of Cyp2b2: 1.28 ± 0.34 vs 4.22 ± 0.51.

Females:

↑ relative liver weight (mg/g body weight): 31.92 ± 0.68 vs 34.36 ± 0.88.

↑ gene expression of Cyp2b1: 1.14 ± 0.42 vs 4.40 ± 1.22.

↑ gene expression of Cyp2b2: 1.02 ± 0.41 vs 4.26 ± 1.36.

Recovery not assessed.

Males:

0.625 / 1.25

Females:

NA / 3.12

A major target organ for PFHxS was the liver.

The lack of, or minimal, liver response with PFHxS in females was very apparent compared to the other PFAS and likely due to the lack of presumed activation of PPARα.

Liver weights appeared to correlate with histopathologic changes in the liver.

K1

This study investigated toxicity of PFHxS following a 28-day exposure.

Liver enzymes were elevated only at higher doses than the LOAEL.

Although authors noted that liver weight changes correlated with hisopathologic changes, results show that hepatocyte hypertrophy occurred at higher doses than the LOAEL.

This study was funded by NTP. The study was audited retrospectively by an independent QA contractor.