Carcinogenic effects of the low doses: the Ramazzini Institute experience. Dr. Fiorella Belpoggi. Annual Ramazzini Days 2012

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1 Cesare Maltoni Cancer Research Centre Ramazzini Institute (CMCRC/RI) Carcinogenic effects of the low doses: the Ramazzini Institute experience Dr. Fiorella Belpoggi Annual Ramazzini Days 2012

2 THE CMCRC/RI Compounds /agents studied: 208 Clear evidence of carcinogenicity: 52

3 THE EFFECTS OF LOW DOSES: SOME EXAMPLES CMCRC 3

4 CMCRC/RI STUDY DESIGN: a human-equivalent model Compared distribution by age at death of: 1,114 people (1/2 both sexes) with malignant tumors (out of 2,560 autopsied men and women deceased at the Hospital of Trieste, in 1989) 1,212 Sprague-Dawley rats (1/2 both sexes) with malignant tumor (out of 3,051 necropsied male and female untreated rats, under control until spontaneous death, used as control groups ) 10 human years are equivalent to 16 weeks in a rat CMCRC 4

5 Human equivalent model 20 (%) Distribution of animals/humans with malignant tumors, histopathologically observed, by age at death Humans Rats 0 Age at death (years) Age at death (weeks) Age: 16 weeks of age in Sprague Dawley rats are considered equivalent to 10 years in humans Data from the Hospital of Trieste were kindly made at our disposal by Professor Luigi Giarelli CMCRC 5

6 The human equivalent model 60 (%) 50 Humans Rats Cumulative prevalence of animals/humans with malignant tumors, histopathologically observed, by age at death Age at death (years) Age at death (weeks) Age: 16 weeks of age in Sprague Dawley rats are considered equivalent to 10 years in humans Data from the Hospital of Trieste were kindly made at our disposal by Professor Luigi Giarelli 80% of tumours arise after the age of 65 years in humans, which corresponds to 104 weeks in rats CMCRC 6

7 Vinyl Chloride (VC) CMCRC 7

8 Exposure by inhalation to VC: results of 5 different experiments on rats Sprague-Dawley Rats Total Malignant Tumours M F No. of Tumours per 100 animals ppm 1 ppm 5 ppm 10 ppm 25 ppm 50 ppm 100 ppm 150 ppm 200 ppm 250 ppm 500 ppm 2,500 ppm 6,000 ppm 10,000 ppm 30,000 ppm Concentration

9 Vinylidene Chloride (VDC) CMCRC 9

10 Exposure by inhalation to VDC: results on 980 mice Swiss Mice Mammary Tumours % of Animals with Mammary Tumours M F 0 0 ppm 10 ppm 25 ppm 50 ppm 100 ppm 200 ppm Concentration

11 Exposure by inhalation to VDC: results on 980 mice 40 Swiss Mice Lung Tumours M F % of Animals with Lung Tumours ppm 10 ppm 25 ppm 50 ppm 100 ppm 200 ppm Concentration

12 Mancozeb Low doses CMCRC 12

13 Exposure by feed to Mancozeb: results on 750 rats 80.0 Sprague-Dawley Rats Total Malignant Tumours M F % of Animals with Malignant Tumours ppm 10 ppm 100 ppm 500 ppm 1,000 ppm Concentration

14 Aspartame (APM) CMCRC 14

15 Prenatal exposure by feed to APM: results on 852 mice Female Swiss Mice Hepatocellular adenomas/carcinomas 10.0 % of Animals with Tumours mg/kg bw 242 mg/kg bw 987 mg/kg bw 1,919 mg/kg bw 3,909 mg/kg bw Concentration

16 Acetaldehyde CMCRC 16

17 Exposure by drink water to Acetaldehyde: results on 600 animals Sprague-Dawley Rats Total Malignant Tumours M F No. of Tumours per 100 animals mg/l 50 mg/l 250 mg/l 500 mg/l 1,500 mg/l 2,500 mg/l Concentration

18 Benzene CMCRC 18

19 Exposure by ingestion to Benzene: results on 370 rats Sprague-Dawley Rats Mammary Tumours M F % of Animals with Mammary Tumours mg/kg bw 50 mg/kg bw 250 mg/kg bw 500 mg/kg bw Concentration

20 Recommendations CMCRC 20

21 Recommendations: duration of the experiment For a more realistic risk assessment, the main changes that the Ramazzini Institute recommends to OECD protocols, on the basis of its 40-year experience in carcinogenicity bioassays, are: The observation period of experimental animals should be prolonged until 130 weeks. In OECD tests, the animals are suppressed at 104 weeks, which corresponds to only 65 years in human terms. 80% of cancers in humans show up after the age of 65, and in rats after the age of 104 weeks, so the OECD protocol misses a large proportion of the potential carcinogenicity of the studied compound In cases when carcinogenic risk of a chemical is observed only at higher doses but not at lower ones, a second experiment in which exposure at low doses starts during the prenatal stage of life (on the 12th day of gestation) should be performed. CMCRC 21

22 Recommendations: synergistic effects The following new scientific insights should be incorporated into standardized tests performed for risk assessment: Study starting from prenatal life of the diffuse carcinogenic risks: very low doses of chemicals in mixtures, which reflect the real-life exposures of billions of people, pose a substantial risk; different compounds which are individually used at concentrations that have previously been demonstrated safe, can act synergistically and together represent a public health risk CMCRC 22

23 Recommendations: endocrine disruptors The following new scientific insights should be incorporated into standardized tests performed for risk assessment: When suspected endocrine disruptors are studied, the in vivo experiments should be planned mirroring the human counterpart in term of windows of susceptibility and doses. An example is following CMCRC 23

24 Mount Sinai School of Medicine-Ramazzini Institute: Project Breast cancer genomics in windows of susceptibility to endocrine disrupters Compoud Diethylphtalate CAS N.: Use Cosmetics and parfums; plasticizer, detergents Metilparaben CAS N.: Antimicotic, cosmetic, personal care, food preservant as E218 Triclosan CAS N.: Disinfectant in personal care products as tooth paste, soaps, parfums, etc. 24

25 Breast cancer genomics in windows of susceptibility to endocrine disruptors Window of susceptibility Treatment (gavage) Start (age) End (age) Duration (days) Animals N. Prenatal Day of mating Delivery (21 days) Mothers during gestational period /21 days 25 Neonatal At birth 3 weeks Mothers starting after delivery/21 days 25 Pre-puberal 3 weeks 6 weeks Offspring for /21 days 25 Puberal 6 weeks 9 weeks Offspring / 21 days 25 Adult, mothers primiparous Adult, nulliparous At birth 180 days Mothers, after weaning offspring, matched and then studied after delivery /180 At birth 180 days Mothers, after weaning offspring / 180 days TOTAL 150

26 Range finding 26

27 Range finding 27

28 Range finding 28

29 BT1ED: scelta delle dosi 29

30 Conclusions Animal models can predict the human situation in appropriate experimental conditions CMCRC 30

31 References 1. Maltoni C, Lefemine G, Ciliberti A, et al. Experimental research on vinyl chloride carcinogenesis. In Maltoni C, Mehlman MA: Archives of research on industrial carcinogenesis, Vol 2. Princeton: Princeton Scientific Publishers, Maltoni, C; Lefemine, G; Cotti, G; et al. (1985) Experimental research on vinylidene chloride carcinogenesis. In: Maltoni, C; Mehlman, MA, eds. Archives of Research on Industrial Carcinogenesis, Volume III. Princeton, NJ: Princeton Scientific. 3. Belpoggi F, Soffritti M, Bua L et al. Results of long-term experimental studies on the carcinogenicity on ethylene-bis-dithiocarbamate (Mancozeb) in rats. Ann NY Acad Sci 2002; 982: Soffritti M, Belpoggi F, Tibaldi E, Degli Esposti D, Lauriola M. Life-span exposure to low doses of aspartame beginning during prenatal life increases cancer effects in rats. Environ Health Perspect 2007; 115: Soffritti M, Belpoggi F, Manservigi M, Tibaldi E, Lauriola M, Falcioni L, Bua L. Aspartame administered in feed, beginning prenatally through life span, induces cancers of the liver and lung in male Swiss mice. Am J Ind Med 2010; 53(12): Soffritti M, Belpoggi F, Lambertini L, Lauriola M, Padovani M, Maltoni C. Results of long-term experimental studies on the carcinogenicity of formaldehyde and acetaldehyde in rats. Ann NY Acad Sci 2002; 982: Maltoni C, Ciliberti A, Cotti G, Conti B, Belpoggi F. Benzene, an experimental multipotential carcinogen: results of the long-term bioassays performed at the Bologna Institute of Oncology. Environ Health Perspect, 1989; 82: CMCRC 31

32 The staff of the CMCRC/IR