Triethylenetetramine (TETA).

The WEEL for triethylenetetramine (TETA; CAS No. 112-24-3) was originally established in 1991 and updated in 1998 and 2009. Recent literature searches to identify new toxicity information were performed in 2016 and January 2021. No new studies or data relevant to the WEEL were identified. TETA is used in manufacturing; the hydrochloride salt of TETA is used as a copper-chelating drug in the treatment of Wilson's disease. TETA is severely irritating to the skin and eyes and produces skin sensitization; however, it is of low to moderate acute toxicity via the oral and dermal routes of exposure. In subchronic studies, signs of toxicity included multi-organ effects (lung, liver, and spleen) in mice, but not rats. TETA was genotoxic/mutagenic in short-term in vitro assays but not in in vivo assays. No data on reproductive toxicity were available. Embryo/fetal toxicity occurred at maternally toxic doses and was associated with copper deficiency. In humans, the use of TETA·2HCl for treatment of Wilson's disease during pregnancy resulted in no miscarriages or fetal abnormalities. No evidence of carcinogenicity was noted in a lifetime dermal study in mice. Based on a subchronic drinking water study in mice, 600 ppm (95 mg/kg-day) was determined to be the no-observed-adverse-effect level (NOAEL) and the point of departure (POD). This NOAEL was converted to an equivalent inhalation concentration by adjusting for respiratory rate, interindividual variability, and uncertainty. The resulting 8-h time-weighted average WEEL value of 1 ppm is expected to provide a significant margin of safety against any potential adverse health effects in workers exposed to airborne TETA.

Effects of triethylene tetraamine on telomerase activity and proliferation in HeLa cells.

Telomerase, which is required to maintain telomeres, has attracted considerable attention as a target for anticancer therapy. In this study, we investigated the inhibition of HeLa cell telomerase activity and cell cycle progression by triethylene tetraamine (TETA), using a modified telomeric repeat amplification protocol (TRAP) assay, and flow cytometry. TETA inhibited telomerase activity in HeLa cell extracts, with an IC50 of about 7.8 microM. Coupled with this inhibition, TETA also increased the proportion of cells in the G1 phase of the cell cycle in a dose-dependent manner. These findings demonstrate that TETA is a potent inhibitor of telomerase in micromolar concentrations, and inhibits the proliferation of HeLa cells by arresting them in G1.

Subacute and chronic toxicity studies of triethylenetetramine dihydrochloride (TJA-250) by oral administration to F-344 rats.

Triethylenetetramine dihydrochloride (trientine-2HCl, TJA-250), a copper chelating agent used to treat Wilson's disease, was administered orally to male and female F-344 rats for 4 or 8 weeks at dosages of 0, 100, 350 or 1200 mg/kg/day or for 26 weeks at dosages of 50, 175 or 600 mg/kg/day. 4 or 8-week study. Two males receiving 1200 mg/kg/day died during week 8 of treatment. In males receiving 1200 mg/kg/day during weeks 5 to 8 of treatment, body weight gain and food consumption were decreased and hunched posture and thin build were observed. During week 4 or 8 of treatment urinalysis revealed, for males receiving 100 mg/kg/day or animals receiving 350 mg/kg/day or more, increased electrolyte outputs possibly due to the hydrochloride nature of trientine-2HCl, with low plasma alkaline phosphatase activities evident in animals receiving 350 or 1200 mg/kg/day. After 4 and 8 weeks, and during 8 weeks of treatment, high lung weights and bronchiolar epithelium hypertrophy and broncho-alveolar pneumonia were recorded for animals receiving 1200 mg/kg/day, and submucosal acute inflammation within the glandular region of the stomach was recorded for males receiving 350 or 1200 mg/kg/day and in all treated female groups. 26-week study. One male receiving 175 mg/kg/day and three males receiving 600 mg/kg/day died, showing lung changes. The body weight gain of animals receiving 600 mg/kg/day was slightly decreased. Blood chemistry and urinalysis examinations showed changes similar to those indicated in the 4- or 8-week study. The low plasma copper concentrations seen in males receiving 600 mg/kg/day, the slightly low liver copper concentrations found in animals receiving 600 or 175 mg/kg/day and the high urinary copper concentrations found in all treated groups, are attributed to the pharmacological action of trientine-2HCl. Histopathology revealed a dosage-related incidence and severity of focal chronic interstitial pneumonitis accompanied by fibrosis of the alveolar walls in females receiving 175 mg/kg/day or more and all treated male groups, but no significant pathological changes in the stomach. Apart from the histological changes found in the lung, all the above changes were reversible. In conclusion, the NOAEL of trientine-2HCl in this 26-week study was considered to be 50 mg/kg/day for females and less than 50 mg/kg/day for males.

Subchronic toxicity of triethylenetetramine dihydrochloride in B6C3F1 mice and F344 rats.

Triethylenetetramine dihydrochloride (trien-2HCl; CAS No. 38260-01-04), a chelating agent used to treat Wilson's disease patients who are intolerant of the drug of choice, was tested for subchronic toxicity in B6C3F1 mice and F344 rats. Mice and rats received trien-2HCl in the drinking water at concentrations of 0, 120, 600, or 3000 ppm for up to 92 days. Twenty mice and 18 rats of each sex were assigned to each dose group fed either a cereal-based (NIH-31) or a purified (AIN-76A) diet, both containing nutritionally adequate levels of copper. An additional control group of rats and mice received a Cu-deficient AIN-76A diet. This low copper diet resulted in Cu-deficiency symptoms, such as anemia, liver periportal cytomegaly, pancreatic atrophy and multifocal necrosis, spleen hematopoietic cell proliferation, and increased heart weight, together with undetectable levels of plasma copper in rats but not in mice. Trien-2HCl lowered plasma copper levels some-what (at 600 and 3000 ppm) in rats fed the AIN-76A diet, but did not induce the usual signs of copper deficiency. Trien-2HCl caused an increased frequency of uterine dilatation at 3000 ppm in rats fed AIN-76A diet that was not noted in females fed the Cu-deficient diet. Trien-2HCl toxicity occurred only in mice in the highest dose group fed an AIN-76A diet. Increased frequencies of inflammation of the lung interstitium and liver periportal fatty infiltration were seen in both sexes, and hematopoietic cell proliferation was seen in the spleen of males. Kidney and body weights were reduced in males as was the incidence of renal cytoplasmic vacuolization. There were no signs of copper deficiency in mice exposed to trien-2HCl. The only effect of trien-2HCl in animals fed the NIH-31 diet was a reduced liver copper level in both rat sexes, noted at 3000 ppm.

Evaluation of the genotoxic potential of alkyleneamines.

A series of 6 alkyleneamines [ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), aminoethylethanolamine (AEEA), and aminoethylpiperazine (AEP)] were evaluated for potential genotoxic activity using a battery of in vitro and in vivo assays. Only TETA was considered mutagenic in the Salmonella typhimurium mutation assay. All 6 alkyleneamines tested except AEP were considered inactive in the Chinese hamster ovary (CHO) gene mutation assay. AEP was considered inconclusive in this assay. In 2 the sister-chromatid exchange (SCE) assay, EDA, DETA and AEEA were inactive with or without metabolic activation. TETA, TEPA and AEP were considered active in the induction of SCE in CHO cells. With hepatocytes, no positive effects of EDA, DETA AEEA and AEP upon unscheduled DNA syntheses (UDS) were noted. However, TETA and TEPA produced significant increases in the amount of UDS activity, and thus were considered positive in inducing primary DNA damage in this assay. In a micronucleus study with Swiss-Webster mice, no clastogenic activity was observed with TETA, TEPA and AEP. The overall weight of evidence from the in vitro and in vivo tests suggested that EDA, DETA and AEEA were not mutagenic, while TETA was mutagenic, and TEPA and AEP had a weak mutagenic potential.

Teratogenic effects of triethylene tetramine dihydrochloride on the mouse brain.

The teratogenic effects of triethylene tetramine dihydrochloride (Trien-2HCl) on fetal mouse brain were studied on gestational day 19. Trien-2HCl was given throughout pregnancy at levels of 0 (control), 3,000, 6,000, or 12,000 mg/liter as drinking water, ad libitum. Mean litter size and live fetus per dam at birth were not significantly different among the four groups. The frequency of gross brain abnormalities in live fetus at birth such as hemorrhages, delayed ossification in cranium, hydrocephaly, exencephaly, and microcephaly increased with increasing levels of the drug. Microscopically, disorganization of neuronal cell layers, spongiform changes in white matter, and reduced myelin development were noted in the coronally sectioned cerebrum from Trien-2HCl-treated fetus. These abnormal findings increased dose-dependently in regard to the extent and severity at the levels of 6,000 and 12,000 mg/liter. No such changes were observed in the cerebrum of controls. These results suggest that microscopic changes in fetal brain caused by Trien-2HCl may be in part similar to those in brindled mutant mouse. Special attention should be paid to the developing fetal brain when Trien-2HCl is used during pregnancy.

Low copper and brain abnormalities in fetus from triethylene tetramine dihydrochloride-treated pregnant mouse.

The effects of prenatal triethylene tetramine dihydrochloride (Trien-2HCl) exposure on fetal mice have been investigated on gestational day 19. Trien-2HCl was given throughout pregnancy at levels of 0 (control), 3,000, 6,000, or 12,000 ppm as drinking water, ad libitum. At the level of 12,000 ppm, the frequency of total resorption tended to be high and that of fetal viability tended to be low, as compared to controls. Decreased maternal weight was observed in body, but not in liver, at the level of 12,000 ppm. Fetal body and cerebrum weights significantly decreased at the levels of 6,000 and 12,000 ppm; however, fetal liver weight remained unchanged. Maternal serum copper concentration was not affected by the Trien-2HCl. Fetal copper concentrations of liver and cerebrum were significantly lower in the Trien-2HCl-treated groups than in the controls, with levels decreasing in a dose-related manner. When the copper and zinc concentrations in the group treated at 12,000 ppm were compared with those in controls, significant decreases in both metals were observed in placenta but not in maternal liver. Changes in fetal zinc concentration varied by tissues: i.e., an increase in liver and no change in cerebrum. Fetal abnormalities were frequently observed in brain, and the frequency was increased with increasing levels of the Trien-2HCl. These results suggest that fetal brain abnormalities caused by Trien-2HCl may be due in part to induction of copper deficiency, which is almost equivalent to that in brindled mutant mouse.

Molecular localization of copper and zinc in rat fetal liver in dietary and drug-induced copper deficiency.

The teratogenicity of copper deficiency is well known, but underlying mechanisms have not been delineated. One method of studying the biochemical lesions of copper deficiency is the use of chelating drugs with different chemical characteristics. The teratogenicity of a copper deficient diet and of diets containing either D-penicillamine or triethylenetetramine is quite different, although all three diets result in decreased fetal liver copper levels. Feeding D-penicillamine can result in decreased fetal liver zinc, while feeding triethylenetetramine can result in increased fetal liver zinc. The effect of these three diets on fetal liver copper and zinc molecular localization was determined. Gel filtration showed that fetal liver copper and zinc in controls was localized in 3 fractions with MWs of greater than 50,000 (H), 30,000 (I) and 8-10,000 (L). Independent of dietary treatment, as liver copper diminished, copper was missing first from the L peak, then the I peak and with severe deficiency, from the H peak. Drug induced increases and decreases in fetal liver zinc were reflected in the L peak. These data suggest that the absolute levels of copper in the liver of the term fetus determines the distribution of the element among its binding ligands.

Teratogenesis and low copper status resulting from triethylenetetramine in rats.

The teratogenicity of triethylenetetramine (TETA) was studied using the Sprague-Dawley rat. TETA was fed during pregnancy at levels of 0 (control), 0.17, 0.83, or 1.66% in a complete purified diet. The frequency of resorptions and the frequency of abnormal fetuses at term increased with increasing levels of the drug. Maternal and fetal tissue copper levels were significantly lower in the TETA groups than in controls, with levels decreasing in a dose-related manner. Maternal kidney and fetal liver zinc levels increased within the TETA groups in a dose-related manner. Maternal liver iron was increased in the high-dose group compared to controls. Fetal iron concentration and maternal and fetal manganese level were not significantly affected by the drug. These results show that TETA can be a teratogenic agent. Furthermore, the results suggest that the teratogenicity of the drug may be due in part to induction of copper deficiency, and perhaps through induction of zinc toxicity.

The effect of copper supplementation on the teratogenic effects of triethylenetetramine in rats.

Previous research from this laboratory has shown that triethylenetetramine (TETA) fed to rats throughout pregnancy at 0.83% or 1.67% of the diet is teratogenic and results in low copper and high zinc levels in material and fetal tissues. These results suggested that the teratogenic effects of TETA were due to copper deficiency and/or zinc toxicity induced by the drug. In the present study, dams were fed TETA in a control (5 micrograms copper/gm) or copper supplemented (50 micrograms copper/gm) diet throughout pregnancy. Fetuses were removed on day 21 of gestation and examined for abnormalities. Copper supplementation reduced the teratogenicity of TETA; the reduction was correlated with an increase in maternal and fetal tissue copper levels. Copper supplementation did not alter the effects of TETA on tissue zinc levels. Thus TETA teratogenicity appears to be due primarily to induced copper deficiency, which may be reduced by dietary copper supplementation.

[Studies on determining the mutagenicity risk of triethylenetetramine (author's transl)]. / Untersuchungen zur abschätzung des Mutagenitätsrisikos von Triethylentertramin.

Triethylenetetramine (TETA) is the only available effective drug for the treatment of patients with Wilson's disease and with simultaneous intolerance to D-penicillamine. In the Ames-test, however both TETA and the structurally similar tetramine BE 6184 are mutagenic. The naturally occurring spermine, a closely related tetramine differing only in one additional methylene group in every carbon chain, shows no mutagenicity. TETA does not exhibit any mutagenic potency in the micronucleus-test.