NTP report on the toxicology studies of aspartame (CAS no. 22839-47-0) in genetically modified (FVB Tg.AC hemizygous) and B6.129-Cdkn2atm1Rdp (N2) deficient mice and carcinogenicity studies of aspartame in genetically modified (B6.129-Trp53tm1Brd (N5) haploinsufficient) mice (feed studies) / National Toxicology Program.

Format:

Book

Author/Creator:

National Toxicology Program, author, issuing body.

Language:

English

Subjects (All):

Aspartame--Toxicology.

Aspartame.

Physical Description:

1 online resource

Place of Publication:

London : National Toxicology Program, 2005.

Summary:

Aspartame is an artificial sweetener used throughout the world in food and beverages. Conventional 2-year rodent cancer studies of aspartame are considered negative, although a small number of neoplasms of the brain were observed in a rat study (Fed. Regist., 1981a,b). The NTP has explored the use of genetically altered mouse models as adjuncts to the 2-year rodent cancer assay. These models may prove to be more rapid, use fewer animals, and provide some mechanistic insights into neoplastic responses. As part of the evaluation of new mouse cancer screening models, aspartame was tested for potential toxicity and carcinogenicity in two relatively well-studied models, the Tg.AC hemizygous strain and the p53 haploinsufficient strain, and an uncharacterized model, the Cdkn2a deficient strain. Male and female Tg.AC hemizygous, p53 haploinsufficient, and Cdkn2a deficient mice were given feed containing aspartame (greater than 98% pure) for 9 months. Genetic toxicology studies were conducted in Salmonella typhimurium, rat bone marrow cells, and mouse peripheral blood erythrocytes. 9-MONTH STUDY IN Tg.AC HEMIZYGOUS MICE: Groups of 15 male and 15 female Tg.AC hemizygous mice were fed diets containing 0, 3,125, 6,250, 12,500, 25,000, or 50,000 ppm aspartame (equivalent to average daily doses of approximately 490, 980, 1,960, 3,960, or 7,660 mg aspartame/kg body weight to males and 550, 1,100, 2,260, 4,420, or 8,180 mg/kg to females) for 40 weeks. Exposure to aspartame had no effect on survival. The mean body weights of 50,000 ppm females were greater than those of the controls from week 15 until the end of the study. Feed consumption by the exposed groups was similar to that by the control groups throughout the study. There were no neoplasms or nonneoplastic lesions that were attributed to exposure to aspartame. 9-MONTH STUDY IN p53 HAPLOINSUFFICIENT MICE: Groups of 15 male and 15 female p53 haploinsufficient mice were fed diets containing 0, 3,125, 6,250, 12,500, 25,000, or 50,000 ppm aspartame (equivalent to average daily doses of approximately 490, 970, 1,860, 3,800, or 7,280 mg/kg to males and 630, 1,210, 2,490, 5,020, or 9,620 mg/kg to females) for 40 weeks. Exposure to aspartame had no effect on survival or mean body weights. Feed consumption by the exposed groups was similar to that by the control groups throughout the study. No neoplasms or nonneoplastic lesions were attributed to exposure to aspartame. 9-MONTH STUDY IN Cdkn2a DEFICIENT MICE: Groups of 15 male and 15 female Cdkn2a deficient mice were fed diets containing 0, 3,125, 6,250, 12,500, 25,000, or 50,000 ppm aspartame for 40 weeks (equivalent to average daily doses of approximately of approximately 490, 960, 1,900, 3,700, and 7,400 mg/kg to males and 610, 1,200, 2,390, 4,850, and 9,560 mg/kg to females). Survival of all exposed groups was similar to that of the control groups. Mean body weights of 3,125 and 6,250 ppm males were less than those of the controls after weeks 29 and 16, respectively. Mean body weights of female mice were similar to those of the controls throughout the study. The incidences of minimal to mild cytoplasmic vacuolization of periportal hepatocytes were significantly greater than controls in males exposed to 6,250, 25,000, or 50,000 ppm aspartame.

Notes:

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