Potentiation of cocaine hepatotoxicity in human hepatocytes by ethanol

Morphological, biochemical and molecular effects of cocaine on mouse neuroblastoma cells culture in vitro

In order to compare the effects of cocaine at morphological, basal cytotoxicity, biochemical and molecular levels, cultured mouse neuroblastoma cells (Neuro-2a) were exposed to a range of concentrations of cocaine hydrochloride. Neuroblastoma cell proliferation, evaluated by quantification of total protein content, was very sensitive to cocaine, being increasingly inhibited from 12 to 72 hr of exposure (EC(50) = 3.1 mm at 24 hr). Cytoplasmic membrane permeability to lactate dehydrogenase was not particularly increased and lysosomal function was stimulated from 0.05 to 1.5 mm, and inhibited from 2.5 mm. A shift to anaerobiosis was detected as intracellular lactate dehydrogenase (LDH) activity was increased and mitochondrial succinate dehydrogenase (SDH) activity decreased. Hexosaminidase (HEX), a lysosomal enzyme involved in sphingolipid degradation, was stimulated only at 1 mm and neural acetylcholinesterase (AChE) activity was stimulated from 2.5 mm. Morphological examination of exposed cultures revealed that most cells became bipolar and multipolar neurons by extension of neurites, but also suffered cytoplasmic vacuolization, hydropic degeneration and nuclear pyknosis. Although cells developing apoptosis were observed, no DNA oligonucleosomal fragmentation was detected by agarose gel electrophoresis of DNA from cells exposed to cocaine. In conclusion, in addition to predominance of anaerobiosis, little disruption of membranes and severe morphologic injury, biochemical and morphological differentiation-like effects were the most prominent alterations produced by cocaine on mouse neuroblastoma cells.

Cocaine metabolism in humans after use of alcohol. Clinical and research implications

The simultaneous administration of cocaine and alcohol implies a pharmacological interaction at pharmacodynamic and pharmacokinetic levels. The latter involves an alteration of cocaine kinetics and metabolism, as well as the biosynthesis of newly active metabolites, such as cocaethylene. Cocaethylene is metabolized along the same pathways as cocaine. Its detection in biological samples indicates the combined consumption of cocaine and alcohol. From epidemiological and toxicological data, it has been suggested that the combination of alcohol and cocaine produces an increased toxicity in addition to behavioral changes. There has been some debate regarding the contribution of cocaethylene to this rise of toxicity. Its pharmacological and toxicological profile is very similar to cocaine. During the interaction of both substances, the rise in cocaine plasma concentrations can explain many of cardiovascular and behavioral effects observed. The contribution of cocaethylene to the interaction is probably minor; its effects are likely additive to those of cocaine. Perhaps its longer elimination half-life can help in understanding long-lasting effects of the alcohol-cocaine combination.

Hepatotoxicity is not increased in alcoholics with positive urinary cocaine metabolites

Cocaine hepatotoxicity in mice has been reported by numerous investigators. Such hepatotoxicity in other animal models has been more difficult to produce. We prospectively assessed 1212 alcoholics admitted for detoxification for historical, clinical and laboratory evidence of concomitant cocaine/crack use and evidence of liver disease. The 470 cocaine positive subjects had both longer durations and higher average daily costs of cocaine/crack use than the 742 cocaine negative subjects, but had a shorter duration of alcohol use. Serum transaminases were higher in the cocaine negative group. There were no clinically severe cases of liver disease or rhabdomyolysis in either group. Serum hepatitis B surface antibody and hepatitis A antibody were more frequent in the cocaine positive subjects. In conclusion, in this large sample of alcoholics abusing cocaine, severe hepatotoxicity was not at all evident. The previous reports of hepatotoxicity may represent co-morbidity. Some possibilities include infection with a hepatitis or other virus, the presence of an adulterant, an idiosyncratic reaction or an enzymatic abnormality.