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Some DCA-Related Animal Studies Note that, Dr. Michelakis used a rate of 75 mg of DCA per liter of drinking water. The rates used that caused cancer in the mice were much higher than used by Dr. Michelakis in his cancer suppression studies. A rate of 2 grams of DCA per liter of water is nearly 27 times that used by Dr. Michelakis. Clearly the risk increases as the dosage of DCA climbs. This was a significant statement: A "no observed effects level' (NOEL) of 0.05 g/l (3.6 mg/kg/day) was the same as for the mouse (3-8 mg/kg/day). See below. 1: Poult Sci. 1993 Jun;72(6):1063-9. Links
1: Toxicol Appl Pharmacol. 1987 Sep 15;90(2):183-9. Links The carcinogenicity of trichloroethylene and its metabolites, trichloroacetic acid and dichloroacetic acid, in mouse liver. Trichloroethylene (TCE) has previously been shown to be carcinogenic in mouse liver when administered by daily gavage in corn oil. The metabolism of TCE results, in part, in the formation of trichloroacetic acid (TCA) as a major metabolite and dichloroacetic acid (DCA) as a minor metabolite. These chlorinated acetic acids have not been shown to be genotoxic, although they have been shown to induce peroxisome proliferation. Therefore, we determined the ability they have been shown to induce peroxisome proliferation. Therefore, we determined the ability of TCE, TCA, or DCA to act as tumor promoters in mouse liver. Male B6C3F1 mice were administered intraperitoneally 0, 2.5, or 10 micrograms/g body wt ethylnitrosourea (ENU) on Day 15 of age. At 28 days of age, the mice were placed on drinking water containing either TCE (3 or 40 mg/liter), TCA (2 or 5 g/liter), or DCA (2 or 5 g/liter). All drinking waters were neutralized with NaOH to a final pH of 6.5-7.5. The animals were killed after 61 weeks of exposure to the treated drinking water (65 weeks of age). Both DCA and TCA at a concentration of 5 g/liter were carcinogenic without prior initiation with ENU, resulting in hepatocellular carcinomas in 81 and 32% of the animals, respectively. DCA and TCA also increased the incidence of animals with adenomas and the number of adenomas/animal in those animals that were not initiated with ENU. While 2.5 micrograms/g body wt ENU followed by NaCl in the drinking water resulted in only 5% of the animals with hepatocellular carcinomas, 2.5 micrograms/g body wt ENU followed with 2 or 5 g/liter DCA resulted in a 66 or 78% incidence of carcinoma, respectively, or, followed with 2 or 5 g/liter TCA, resulted in a 48% incidence at either concentration. None of the untreated animals had hepatocellular carcinomas. Therefore our results demonstrate that DCA and TCA are complete hepatocarcinogens in B6C3F1 mice. PMID: 3629594 [PubMed - indexed for MEDLINE] 1: Life Sci. 1987 Nov 2;41(18):2167-76. Links Dichloroacetate (DCA) reduces blood glucose, lactate and lipids in diabetes or during fasting. Chronic use of DCA, however, is limited by toxicity, probably due in part to its rapid conversion to oxalate in vivo. In theory, therefore, DCA's efficacy may be retained and its toxicity minimized by controlling its rate of metabolism. We attempted to alter DCA pharmacokinetics and bioavailability by synthesizing various derivatives comprising DCA esters with polyols and DCA ionic complexes. Twenty-four hour fasted, nondiabetic rats received single, orogastric doses of saline (control) sodium DCA (100mg/kg) or the following derivatives (D1-4): the esters D1-D3: potassium tetra (dichloroacetyl) glucuronate (D1), inositol-monophosphate-tetradichloroacetate (D2), inositol-hexadichloroacetate (D3) and inositol-hexa [N-methylnicotinate] hexadichloroacetate salt (D4). Each derivative was administered at a dose that would ultimately provide 100 mg/kg DCA as the anion. All derivatives were orally effective in significantly decreasing blood glucose and lactate. D4 exerted the most potent and long-lasting glucose- and lactate-lowering effects, yet increased plasma DCA concentrations less than an equivalent dose of the sodium salt. When administered to reverse light-cycled rats, D4 markedly inhibited the incorporation of tritiated water into cholesterol and triglycerides. We conclude that derivatives of DCA retain the biological activity of the parent compound, but may exhibit different pharmacokinetics. They may eventually prove useful in the treatment of diabetes mellitus, hyperlipidemia and lactic acidosis in man. 1: J Toxicol Environ Health A. 1999 Dec 24;58(8):485-507. Links Male B6C3F, mice were exposed to dichloroacetic acid (DCA) in the drinking water in order to establish a dose response for the induction of hepatocellular cancer and to examine several modes of action for the carcinogenic process. Groups of animals were exposed to control, 0.05, 0.5, 1, 2, or 3.5 g/L DCA in the drinking water for 90-100 wk. Mean daily doses (MDD) of 8, 84, 168, 315, and 429 mg/kg/d of DCA were calculated. The prevalence (percent of animals) with hepatocellular carcinoma (HC) was significantly increased in the 1-g/L (71%), 2-g/L (95%), and 3.5-g/L (100%) treatment groups when compared to the control (26%). HC multiplicity (tumors/animal) was significantly increased by all DCA treatments-0.05 g/L (0.58), 0.5 g/L (0.68), 1 g/L (1.29), 2 g/L (2.47), and 3.5 g/L (2.90)-compared to the control group (0.28). Based upon HC multiplicity, a no-observed-effect level (NOEL) for hepatocarcinogenicity could not be determined. Hepatic peroxisome proliferation was significantly increased only for 3.5 g/L DCA treatment at 26 wk. and did not correlate with the liver tumor response. The severity of hepatotoxicity increased with DCA concentration. Below 1 g/L, hepatotoxicity was mild and transient as demonstrated by the severity indices and serum lactate dehydrogenase activity. An analysis of generalized hepatocyte proliferation reflected the mild hepatotoxicity and demonstrated no significant treatment effects on the labeling index of hepatocytes outside proliferative lesions. Consequently, the induction of liver cancer by DCA does not appear to be conditional upon peroxisome induction or chemically sustained cell proliferation. Hepatotoxicity, especially at the higher doses, may exert an important influence on the carcinogenic process. PMID: 10632141 [PubMed - indexed for MEDLINE] 1: Toxicology. 1996 Dec 18;114(3):207-21. The chlorinated acetic acids, in particular dichloroacetic acid (DCA), are found as chlorine disinfection by-products in finished drinking water supplies. DCA has previously been demonstrated to be a mouse liver carcinogen. Chronic studies are described in which male Fischer (F344) rats were exposed to DCA in their drinking water. In the first study, 28 day old rats were exposed to a regimen of 0.05, 0.5 and 5.0 g/l DCA. When animals in the high dose group began to exhibit peripheral hind leg neuropathy, the dose was lowered in stages to 1 g/l. These animals were sacrificed at 60 weeks due to the severe, irreversible neuropathy and were not included in this analysis. The remaining groups of animals were treated for 100 weeks. In the second study, rats were initially exposed to 2.5 g/l DCA which was lowered to 1 g/l after 18 weeks. The mean daily concentration (MDC) of 1.6 g/l was calculated over the 103 week exposure period. Time-weighted mean daily doses (MDD) based on measured water consumption were 3.6, 40.2 and 139 mg/kg bw/day for the 0.05, 0.5 and 1.6 g/l DCA respectively. Based upon the pathologic examination, DCA induced observable signs of toxicity in the nervous system, liver and myocardium. However, treatment related neoplastic lesions were observed only in the liver. A statistically significant increase of carcinogenicity (hepatocellular carcinoma) was noted at 1.6 g/l DCA. Exposure to 0.5 g/l DCA increased-hepatocellular neoplasia, (carcinoma and adenoma) at 100 weeks. These data demonstrate that DCA is an hepatocarcinogen to the male F344 rat. Calculation of the MDD at which 50% of the animals exhibited liver neoplasia indicated that the F344 male rat (approximately 10 mg/kg bw/day) is ten times more sensitive than the B6C3F1 male mouse (approximately 100 mg/kg bw/day). A "no observed effects level' (NOEL) of 0.05 g/l (3.6 mg/kg/day) was the same as for the mouse (3-8 mg/kg/day). PMID: 8980710 [PubMed - indexed for MEDLINE] 1: Toxicol Sci. 2004 Feb;77(2):243-8. Epub 2003 Dec 2. Links Dichloroacetic acid (DCA) is a liver carcinogen that induces DNA hypomethylation in mouse liver. To test the involvement of DNA hypomethylation in the carcinogenic activity of DCA, we determined the effect of methionine on both activities. Female B6C3F1 mice were administered 3.2 g/l DCA in their drinking water and 0, 4.0, and 8.0 g/kg methionine in their diet. Mice were sacrificed after 8 and 44 weeks of exposure. After 8 weeks of exposure, DCA increased the liver/body weight ratio and caused DNA hypomethylation, glycogen accumulation, and peroxisome proliferation. Methionine prevented completely the DNA hypomethylation, reduced by only 25% the glycogen accumulation, and did not alter the increased liver/body weight ratio and the proliferation of peroxisomes induced by DCA. After 44 weeks of exposure, DCA induced foci of altered hepatocytes and hepatocellular adenomas. The multiplicity of foci of altered hepatocytes/mouse was increased from 2.41 +/- 0.38 to 3.40 +/- 0.46 by 4.0 g/kg methionine and decreased to 0.94 +/- 0.24 by 8.0 g/kg methionine, suggesting that methionine slowed the progression of foci to tumors. The low and high concentrations of methionine reduced the multiplicity of liver tumors/mouse from 1.28 +/- 0.31 to 0.167 +/- 0.093 and 0.028 +/- 0.028 (i.e., by 87 and 98%, respectively). Thus, the prevention of liver tumors by methionine was associated with its prevention of DNA hypomethylation, indicating that DNA hypomethylation was critical for the carcinogenic activity of DCA. PMID: 14657517 [PubMed - indexed for MEDLINE 90-Day Toxicity Study of Dichloroacetate in Dogs J. L. CICMANEC*, L. W. CONDIE*, G. R. OLSON and SHIN-RU WANG Received September 25, 1990; accepted April 18, 1991 90-Day Toxicity Study of Dichloroacetate in Dogs. CICMANEC, J. L., CONDIE, L W., OLSON, G. R., AND WANG, S. R. (1991). Fundam. Appl. Toxrcol. 17,376–389. Male and female juvenile beagle dogs were dosed daily for 90 days with dichloroacetate (DCA). The compound was administered orally was gelatin capsules at doses of 0, 12.5, 39.5, and 72 mg/kg/day. Each dose group consisted of five males and five females. The dogs were observed clinically and blood samples were taken at 15-day intervals for hematologic and serum chemistry values. Decreased total erythrocyte count and hemoglobin levels were observed in mid- and high-dose beginning at Day 30. Serum concentrations of LDH were elevated at Days 30 and 45 in females and at Day 75 in males treated with DCA at 72 mg/kg/day. One female of the high-dose group died at Day 50 and two high-dose males died at Days 51 and 74. Hindlimb partial paralysis was observed in many high-dose dogs Vacuolization of myelinated white tracts of cerebrum, cerebellum, and/or spinal cord was observed in many high-dose dogs as well as some mid- and low-dose subjects Degeneration of testicular germinal epithelium and syncytial giant cell formation was noted in males of all dose groups. Hepatic vacuolar change and chronic hepatitis appeared only in DCA-treated dogs. In addition, suppurative bronchopneumonia and chronic pancreatitis were noted in many high-dose and some middose subjects. A "no-adverse-effect level" was not determined In this study. The collection of articles below is from " Haloacetic Acids in Drinking Water", a Canadian publication. I have edited out the sections not pertaining to DCA. http://www.hc-sc.gc.ca/ahc-asc/public-consult/consultations/col/ha-ah/rep-rapp_e.html 10. Health Effects in Laboratory Animals and In Vitro Test Systems 10.2.2 Dichloroacetic acid In a 12-week dietary study, hind limb weakness and abnormal gait also appeared in male Wistar rats (n = 6) exposed to DCA (neutralized). Approximate doses varied from 4 mmol/kg bw per day (516 mg/kg bw per day) at the beginning of the study to about 2.5 mmol/kg bw per day (323 mg/kg bw per day) at the end of the study (Yount et al., 1982). Decreased nerve conduction velocity was also detected in several nerves (sural and motor), as well as a decrease in the diameter of the tibial nerves. Decreased weight gain as a result of decreased food consumption and the presence of hepatomegaly were among the other toxic effects observed. In a 3-month oral gavage study, DCA (sodium salt) was administered to Sprague-Dawley rats (10 per sex per dose) at dose levels of 0, 125, 500 or 2000 mg/kg bw per day, with an additional five rats per sex dosed with 0 or 2000 mg/kg bw per day allowed a 4-week recovery period (Katz et al., 1981). Death was seen in two rats per sex at the high dose. Hind limb paralysis occurred in 27% per sex at the high dose. In the 4-week recovery group, one rat per sex afflicted by the paralysis seemed to have recovered completely. Histopathological examination showed the brain and testes as the main target organs. Oedematous brain lesions, characterized by vacuolation of the myelinated white tracts, were seen in the cerebrum and, to a lesser extent, the cerebellum. Combined incidence rates for these were 60% in the low dose and 100% in the mid- and high doses. In the high-dose recovery group, brain lesions persisted in 3/8 rats. Body weight was decreased in all treated rats and was associated with reduced food consumption. A significant increase was observed in relative liver weight (both sexes, all doses), relative kidney weight (females, all doses) and relative adrenal weight (males, 500 mg/kg bw per day and above; females, 2000 mg/kg bw per day). Clinical chemistry showed a mild depression of the erythroid parameters at the mid- and high doses and a decrease in blood glucose and lactate levels at all levels. Testicular effects were also seen and are discussed in Section 10.5.2 In a 90-day drinking water study, male Sprague-Dawley rats (n = 10) were treated with DCA (neutralized) at doses of 0, 50, 500 or 5000 mg/L (0, 4, 35 or 350 mg/kg bw per day) (Mather et al., 1990). Decreased body weight and water consumption were observed at 35 mg/kg bw per day and above. Relative liver and kidney weights were decreased at doses of 35 mg/kg bw per day and above. However, histological and biochemical signs of liver and kidney damage, as well as an increase in the hepatic peroxisomal beta-oxidation activity, were seen only in the highest dose group. Increases in relative spleen weight were seen at the top dose in the absence of histopathological effects. No effects on immunological functions were seen. In a 13-week drinking water study (NTP, 2000), B6C3F1 mice (10 per sex per dose) were exposed to DCA (neutralized to pH 5) doses of 0, 67, 125, 250, 500 or 1000 mg/L (0, 9, 16, 32, 61 and 124 mg/kg bw per day for males and 0, 10, 18, 38, 72 and 132 mg/kg bw per day for females). Dose-related increases were seen in liver weight and incidence of cytoplasmic vacuolation change in hepatocytes (females at 10 mg/kg bw per day and above; males at 32 mg/kg bw per day and above). No clinical signs or deaths were observed during the study. In the high-dose group, mild leukopenia, neutropenia and monocytopenia were observed in some male mice, which were potentially chemical-related. The authors set NOAELs of <32 mg/kg bw for males and <10 mg/kg bw for females, both based on microscopic liver lesions. NTP (2000) also dosed Fischer-344 rats (10 per sex per dose) with the same protocol and doses as above (calculated doses: males: 0, 5, 9.3, 18.8, 39.2 and 81.4 mg/kg bw per day; females: 0, 5.9, 10.0, 20.9, 43.8 and 94.7 mg/kg bw per day). A significant decrease in body weight gain was noted in high-dose males during weeks 4-13. No other significant effects were observed. In a 13-week subchronic study (Katz et al., 1981), 10- to 12-month-old beagle dogs (3-4 per sex per dose) received DCA (sodium salt) in gelatin capsules at doses of 0, 50, 75 or 100 mg/kg bw per day, with one additional dog per sex dosed with 0 or 100 mg/kg bw per day and allowed a 4-week recovery period. In female dogs only, food consumption was reduced at all doses; however, dose-dependent weight losses at all dose levels were observed in both sexes during the treatment but reversed upon cessation. One female and one male died at the 75 and 100 mg/kg bw per day dose, respectively, and signs of adverse effects observed prior to their deaths included anorexia, ataxia, hind limb weakness and reduced activity. Other adverse effects related to the treatment include emesis (75 and 100 mg/kg bw per day), bloody stools (100 mg/kg bw per day) and paralysis (100 mg/kg bw per day). Also reported in all dose groups (both sexes) were a high incidence of ocular anomalies: bilateral lenticular opacities, injected bulbar conjunctivae and superficial corneal vascularization with a tendency for keratoconjunctivitis sicca. Haematological parameters were depressed at all dose levels in both sexes. Liver and kidney parameters were not affected by the DCA treatment in dogs. An increase in the incidence of lung consolidation was observed in all doses (both sexes). Histopathological examination of the brain revealed that dogs (in all treated groups) suffered slight to moderate vacuolization of white myelinated tracts in the cerebrum and also in the cerebellum, but to a lesser extent. Increases in the incidence of haemosiderin-laden Kupffer cells in the liver and cystic mucosal hyperplasia in the gall bladder were observed at all dose levels, even 5 weeks after cessation of the treatment. Prostate and testicular changes were also seen at 50 mg/kg bw per day and above and are discussed in Section 10.5.2. The authors noted that beagle dogs are more susceptible to cataract formation than any other species (Katz et al., 1981). (discussed above, already) In another subchronic dog study (Cicmanec et al., 1991), 4-month-old male and female beagle dogs (five per sex per dose) received DCA (neutralized to pH 7.4) in gelatin capsules at 0, 12.5, 39.5 or 72 mg/kg bw per day for 90 days. The controls received encapsulated distilled water. Three high-dose animals died as a result of dehydration and pneumonia. Overt clinical signs such as dyspnoea (mid- and high-dose) and partial paralysis (high dose only) were observed in both sexes. Diarrhoea was present in the mid- and high-dose animals; some dogs that were highly dehydrated required fluid therapy. Inflammation of the ocular membranes was accompanied by swelling; discharge was clear at the two lowest doses and became purulent in the high-dose group. A dose-related decrease in body weight gain was observed in all treated animals. Relative liver weights were increased in all female dose groups; however, kidney and lung weights were increased only in the high-dose group. In male dogs, the effects in these organs were less consistent. Apparent increases in ALT, AST and lactate dehydrogenase were observed in both sexes in the high-dose group. Erythrocytes and haemoglobin concentrations were significantly reduced in both sexes in the high-dose group from day 30 and beyond. Upon microscopic examination, lesions were apparent in the liver, brain, lung, pancreas and testes. Hepatic vacuolization was observed in most of the treated dogs (both sexes) as well as in a few control animals. In the brain, mild vacuolization of the white myelinated tracts of the cerebrum, cerebellum and/or spinal cord was present in all exposed groups. Pneumonia and bronchopneu-monia was observed in most treated dogs; more severe effects were seen in the mid-and high-dose groups. Pancreatic acinar associated with chronic inflammation was observed in many mid- and high-dose animals (both sexes). Testicular (all doses) and prostatic effects (mid- and high doses) were seen and discussed in Section 10.5.2. Last Updated: 2006-07-04 Important Notices (Circulation Research. 2004;95:830.) © 2004 American Heart Association, Inc. Integrative Physiology Dichloroacetate Prevents and Reverses Pulmonary Hypertension by Inducing Pulmonary Artery Smooth Muscle Cell Apoptosis The pulmonary arteries (PA) in pulmonary arterial hypertension (PAH) are constricted and remodeled;. They have suppressed apoptosis, partly attributable to suppression of the bone morphogenetic protein axis and selective downregulation of PA smooth muscle cell (PASMC) voltage-gated K+ channels, including Kv1.5. The Kv downregulation-induced increase in [K+]i, tonically inhibits caspases, further suppressing apoptosis. Mitochondria control apoptosis and produce activated oxygen species like H2O2, which regulate vascular tone by activating K+ channels, but their role in PAH is unknown. We show that dichloroacetate (DCA), a metabolic modulator that increases mitochondrial oxidative phosphorylation, prevents and reverses established monocrotaline-induced PAH (MCT-PAH), significantly improving mortality. Compared with MCT-PAH, DCA-treated rats (80 mg/kg per day in drinking water on day 14 after MCT, studied on day 21) have decreased pulmonary, but not systemic, vascular resistance (63% decrease, P<0.002), PA medial thickness (28% decrease, P<0.0001), and right ventricular hypertrophy (34% decrease, P<0.001). DCA is similarly effective when given at day 1 or day 21 after MCT (studied day 28) but has no effect on normal rats. DCA depolarizes MCT-PAH PASMC mitochondria and causes release of H2O2 and cytochrome c, inducing a 10-fold increase in apoptosis within the PA media (TUNEL and caspase 3 activity) and decreasing proliferation (proliferating-cell nuclear antigen and BrdU assays). Immunoblots, immunohistochemistry, laser-captured microdissection-quantitative reverse-transcription polymerase chain reaction and patch-clamping show that DCA reverses the Kv1.5 downregulation in resistance PAs. In summary, DCA reverses PA remodeling by increasing the mitochondria-dependent apoptosis/proliferation ratio and upregulating Kv1.5 in the media. We identify mitochondria-dependent apoptosis as a potential target for therapy and DCA as an effective and selective treatment for PAH Dichloroacetate as metabolic therapy for Clinical Investigations American Heart Journal. 134(5 (Part 1)):841-855, November 1997. (Circulation Research. 2004;95:830.) Dichloroacetate Prevents and Reverses Pulmonary Hypertension by Inducing Pulmonary Artery Smooth Muscle Cell Apoptosis The pulmonary arteries (PA) in pulmonary arterial hypertension (PAH) are constricted and remodeled;. They have suppressed apoptosis, partly attributable to suppression of the bone morphogenetic protein axis and selective downregulation of PA smooth muscle cell (PASMC) voltage-gated K+ channels, including Kv1.5. The Kv downregulation-induced increase in [K+]i, tonically inhibits caspases, further suppressing apoptosis. Mitochondria control apoptosis and produce activated oxygen species like H2O2, which regulate vascular tone by activating K+ channels, but their role in PAH is unknown. We show that dichloroacetate (DCA), a metabolic modulator that increases mitochondrial oxidative phosphorylation, prevents and reverses established monocrotaline-induced PAH (MCT-PAH), significantly improving mortality. Compared with MCT-PAH, DCA-treated rats (80 mg/kg per day in drinking water on day 14 after MCT, studied on day 21) have decreased pulmonary, but not systemic, vascular resistance (63% decrease, P<0.002), PA medial thickness (28% decrease, P<0.0001), and right ventricular hypertrophy (34% decrease, P<0.001). DCA is similarly effective when given at day 1 or day 21 after MCT (studied day 28) but has no effect on normal rats. DCA depolarizes MCT-PAH PASMC mitochondria and causes release of H2O2 and cytochrome c, inducing a 10-fold increase in apoptosis within the PA media (TUNEL and caspase 3 activity) and decreasing proliferation (proliferating-cell nuclear antigen and BrdU assays). Immunoblots, immunohistochemistry, laser-captured microdissection-quantitative reverse-transcription polymerase chain reaction and patch-clamping show that DCA reverses the Kv1.5 downregulation in resistance PAs. In summary, DCA reverses PA remodeling by increasing the mitochondria-dependent apoptosis/proliferation ratio and upregulating Kv1.5 in the media. We identify mitochondria-dependent apoptosis as a potential target for therapy and DCA as an effective and selective treatment for PAH
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