Overdose and addiction are two medical complications of cocaine abuse. To date, there is no FDA approved pharmacotherapy specific for cocaine abuse. Cocaine hydrolases (CocHs) have been extensively investigated for its potential in anti-cocaine therapy. Previous studies have demonstrated that CocHs efficiently hydrolyze cocaine to generate biologically inactive metabolites both in vivo and in vitro. However, it has not been studied whether there is gender difference in the therapy using CocHs. In addition, the effectiveness of CocHs is unknown for treating cocaine toxicity when alcohol is co-administered. The main purpose of this dissertation is to characterize and evaluate efficient CocHs for cocaine overdose and cocaine addiction treatment. In the first set of studies, the effectiveness of human serum albumin-fused CocH1 were studied in male and female rats. The pharmacokinetic profiles, as well as the pharmacodynamic effects of CocH1-HSA were compared in male and female rats. The obtained data clearly demonstrated that CocH1-HSA was equally effective in both genders. The second set of studies investigated the efficiency of Fc-fused CocH5 in reversing cocaine toxicity in rats receiving simultaneous administration of cocaine and alcohol. Results showed that CocH5-Fc rapidly hydrolyzed cocaine and cocaine’s toxic metabolites in rats, and demonstrated that CocH5-Fc was efficient in treating cocaine toxicity when alcohol was simultaneously administered. In later studies to investigate the effects of CocH5-Fc for the treatment of cocaine addiction, a mathematical model was developed and validated to predict the effects of CocH5-Fc on the disposition of cocaine in rat blood and brain. This model adequately described the effects of CocH5-Fc in accelerating the elimination of cocaine and its toxic metabolites in both rat blood and brain. In conclusion, the studies within the current dissertation demonstrate the clinical potential of CocHs for the treatment of both cocaine overdose and cocaine addiction.

Introdução: o crack é uma forma extremamente aditiva de cocaína, provocando intensa fissura e um comportamento persistente e intenso de busca pela droga com negligência da alimentação. A alimentação insuficiente pode levar à carência de tiamina. O uso de latas e folhas de alumínio na confecção de cachimbos para o consumo de crack aumenta a exposição de usuários de crack a este metal. Deficiência de tiamina somada a acúmulo cerebral de alumínio pode inibir o metabolismo energético dependente da glicose, levando à neurodegeneração e, possivelmente, à encefalopatia de Wernicke. Objetivos: avaliação dos níveis sanguíneos de tiamina difosfato e de alumínio de dependentes de crack e comparação com os de controles. Método: estudo transversal controlado, avaliou 35 dependentes de crack e 35 controles, do sexo masculino, com 18 anos ou mais. Os casos foram recrutados entre pacientes internados na Unidade de Adição do Hospital de Clínicas de Porto Alegre ou na Emergência em Saúde Mental IAPI, os controles foram recrutados entre as pessoas que circulam na área ambulatorial do Hospital de Clínicas de Porto Alegre. Todos participantes tiveram seu peso e estatura medidos e sangue coletado para determinação dos níveis de tiamina difosfato e de alumínio. Os casos passaram, também, por uma breve avaliação neurológica. Resultados: as características dos casos são semelhantes à amostra do principal estudo nacional sobre o uso de crack no Brasil: sexo masculino, cerca de 30 anos de idade, com baixa escolaridade, desempregados, usuários de múltiplas substâncias psicoativas, consumidores de crack há aproximadamente 8 anos. O índice de massa corporal dos casos foi significativamente mais baixo (p<0.0001). Seis casos (17.65%) apresentaram índice de massa corporal abaixo do normal. Dois casos apresentaram nível de tiamina abaixo dos valores de referência, enquanto os níveis dos controles estavam acima deste limite. Comparando os resultados do primeiro quartil do nível sanguíneo de tiamina dos casos (N= 9; mediana 3.6μg/dL, amplitude interquartil 3.05μg/dL -4.10μg/dL) com o dos controles (N=14, mediana 4.3μg/dL, amplitude interquartil 3.7μg/dL-4.4μg/dL), os casos apresentaram níveis significativamente mais baixos (p=0.024). Os níveis de alumínio dos casos que tiveram as amostras de sangue coletadas até 24h após o último consumo da substância, foram maiores (mediana1.85μg/L, amplitude interquartil0.65-4.425μg/L) que os dos controles (mediana 0.95μg/L, amplitude interquartil 0.7-1.22μg/L), mas esta diferença não atingiu significância estatística (p=0.07). Conclusões: dependentes de crack tem índice de massa corporal menor e estão mais expostos ao alumínio que os controles. Alguns tem deficiência de tiamina, a qual pode levar à encefalopatia de Wernicke e declínio cognitivo. Portanto, tiamina parenteral profilática deve ser considerada para alguns dependentes de crack. / Background: Crack-cocaine is an extremely additive form of cocaine and its compulsive use can last days until exhaustion, driving its users to neglect feeding. Poor feeding may cause thiamine deficiency. In Brazil, crack-cocaine is usually smoked in pipes made of aluminum cans or with aluminum foils. Insufficient brain levels of thiamine plus brain aluminum accumulation, may impair glucose energy metabolism, promoting neurodegeneration and possibly Wernicke’s encephalopathy. Objectives: The aim of this study was to evaluate thiamine and aluminum blood levels in crack-cocaine addicts and compare them to healthy controls. Methods: cross-sectional controlled study, included 35 crack-cocaine addicts and 35 healthy controls, all males, 18 or older. Cases were recruited at the Addiction Unit of Hospital de Clínicas de Porto Alegre or at the Mental Health Emergency IAPI, controls were recruited between people circulating in the outpatient clinic area of Hospital de Clínicas de Porto Alegre. Weight and height were measured and blood samples collected for determination of thiamine diphosphate and aluminum levels. Cases were also submitted to a brief neurological examination. Results: cases characteristics were similar to the sample of the main national study related to crack-cocaine use in Brazil: mainly males, about 30 years old, with low education level, unemployed, multiple drug abusers, consuming crack-cocaine for approximately 8 years. Body mass index was significantly lower in cases (p<0.0001). Six cases (17.65%) had body mass index lower than normal, while no control was below this limit. Two cases presented thiamine levels below the laboratory reference range, while controls were all above this limit. Comparing the lower quartile of thiamine blood levels, cases (3.6 μg/dL) had significantly lower levels of thiamine than controls (4.3μg/dL) (p=0.024). Blood aluminum median of crack-cocaine addicts (1.85μg/L, interquartile range 0.65-4.425μg/L) whose samples were drawn until 24h after last drug consumption was higher than controls (0.95μg/L, interquartile range 0.7-1.22μg/L), but the difference did not achieve statistical significance (p=0.07). Conclusions: Crack-cocaine addicts have lower BMI and are more exposed to aluminum in comparison to healthy controls. Also, some of them have thiamine deficiency which may lead to Wernicke’s encephalopathy and cognitive impairment. Thus, prophylactic parenteral thiamine should be considered to some crack-cocaine addicts.

Introdução: o crack é uma forma extremamente aditiva de cocaína, provocando intensa fissura e um comportamento persistente e intenso de busca pela droga com negligência da alimentação. A alimentação insuficiente pode levar à carência de tiamina. O uso de latas e folhas de alumínio na confecção de cachimbos para o consumo de crack aumenta a exposição de usuários de crack a este metal. Deficiência de tiamina somada a acúmulo cerebral de alumínio pode inibir o metabolismo energético dependente da glicose, levando à neurodegeneração e, possivelmente, à encefalopatia de Wernicke. Objetivos: avaliação dos níveis sanguíneos de tiamina difosfato e de alumínio de dependentes de crack e comparação com os de controles. Método: estudo transversal controlado, avaliou 35 dependentes de crack e 35 controles, do sexo masculino, com 18 anos ou mais. Os casos foram recrutados entre pacientes internados na Unidade de Adição do Hospital de Clínicas de Porto Alegre ou na Emergência em Saúde Mental IAPI, os controles foram recrutados entre as pessoas que circulam na área ambulatorial do Hospital de Clínicas de Porto Alegre. Todos participantes tiveram seu peso e estatura medidos e sangue coletado para determinação dos níveis de tiamina difosfato e de alumínio. Os casos passaram, também, por uma breve avaliação neurológica. Resultados: as características dos casos são semelhantes à amostra do principal estudo nacional sobre o uso de crack no Brasil: sexo masculino, cerca de 30 anos de idade, com baixa escolaridade, desempregados, usuários de múltiplas substâncias psicoativas, consumidores de crack há aproximadamente 8 anos. O índice de massa corporal dos casos foi significativamente mais baixo (p<0.0001). Seis casos (17.65%) apresentaram índice de massa corporal abaixo do normal. Dois casos apresentaram nível de tiamina abaixo dos valores de referência, enquanto os níveis dos controles estavam acima deste limite. Comparando os resultados do primeiro quartil do nível sanguíneo de tiamina dos casos (N= 9; mediana 3.6μg/dL, amplitude interquartil 3.05μg/dL -4.10μg/dL) com o dos controles (N=14, mediana 4.3μg/dL, amplitude interquartil 3.7μg/dL-4.4μg/dL), os casos apresentaram níveis significativamente mais baixos (p=0.024). Os níveis de alumínio dos casos que tiveram as amostras de sangue coletadas até 24h após o último consumo da substância, foram maiores (mediana1.85μg/L, amplitude interquartil0.65-4.425μg/L) que os dos controles (mediana 0.95μg/L, amplitude interquartil 0.7-1.22μg/L), mas esta diferença não atingiu significância estatística (p=0.07). Conclusões: dependentes de crack tem índice de massa corporal menor e estão mais expostos ao alumínio que os controles. Alguns tem deficiência de tiamina, a qual pode levar à encefalopatia de Wernicke e declínio cognitivo. Portanto, tiamina parenteral profilática deve ser considerada para alguns dependentes de crack. / Background: Crack-cocaine is an extremely additive form of cocaine and its compulsive use can last days until exhaustion, driving its users to neglect feeding. Poor feeding may cause thiamine deficiency. In Brazil, crack-cocaine is usually smoked in pipes made of aluminum cans or with aluminum foils. Insufficient brain levels of thiamine plus brain aluminum accumulation, may impair glucose energy metabolism, promoting neurodegeneration and possibly Wernicke’s encephalopathy. Objectives: The aim of this study was to evaluate thiamine and aluminum blood levels in crack-cocaine addicts and compare them to healthy controls. Methods: cross-sectional controlled study, included 35 crack-cocaine addicts and 35 healthy controls, all males, 18 or older. Cases were recruited at the Addiction Unit of Hospital de Clínicas de Porto Alegre or at the Mental Health Emergency IAPI, controls were recruited between people circulating in the outpatient clinic area of Hospital de Clínicas de Porto Alegre. Weight and height were measured and blood samples collected for determination of thiamine diphosphate and aluminum levels. Cases were also submitted to a brief neurological examination. Results: cases characteristics were similar to the sample of the main national study related to crack-cocaine use in Brazil: mainly males, about 30 years old, with low education level, unemployed, multiple drug abusers, consuming crack-cocaine for approximately 8 years. Body mass index was significantly lower in cases (p<0.0001). Six cases (17.65%) had body mass index lower than normal, while no control was below this limit. Two cases presented thiamine levels below the laboratory reference range, while controls were all above this limit. Comparing the lower quartile of thiamine blood levels, cases (3.6 μg/dL) had significantly lower levels of thiamine than controls (4.3μg/dL) (p=0.024). Blood aluminum median of crack-cocaine addicts (1.85μg/L, interquartile range 0.65-4.425μg/L) whose samples were drawn until 24h after last drug consumption was higher than controls (0.95μg/L, interquartile range 0.7-1.22μg/L), but the difference did not achieve statistical significance (p=0.07). Conclusions: Crack-cocaine addicts have lower BMI and are more exposed to aluminum in comparison to healthy controls. Also, some of them have thiamine deficiency which may lead to Wernicke’s encephalopathy and cognitive impairment. Thus, prophylactic parenteral thiamine should be considered to some crack-cocaine addicts.

Introdução: o crack é uma forma extremamente aditiva de cocaína, provocando intensa fissura e um comportamento persistente e intenso de busca pela droga com negligência da alimentação. A alimentação insuficiente pode levar à carência de tiamina. O uso de latas e folhas de alumínio na confecção de cachimbos para o consumo de crack aumenta a exposição de usuários de crack a este metal. Deficiência de tiamina somada a acúmulo cerebral de alumínio pode inibir o metabolismo energético dependente da glicose, levando à neurodegeneração e, possivelmente, à encefalopatia de Wernicke. Objetivos: avaliação dos níveis sanguíneos de tiamina difosfato e de alumínio de dependentes de crack e comparação com os de controles. Método: estudo transversal controlado, avaliou 35 dependentes de crack e 35 controles, do sexo masculino, com 18 anos ou mais. Os casos foram recrutados entre pacientes internados na Unidade de Adição do Hospital de Clínicas de Porto Alegre ou na Emergência em Saúde Mental IAPI, os controles foram recrutados entre as pessoas que circulam na área ambulatorial do Hospital de Clínicas de Porto Alegre. Todos participantes tiveram seu peso e estatura medidos e sangue coletado para determinação dos níveis de tiamina difosfato e de alumínio. Os casos passaram, também, por uma breve avaliação neurológica. Resultados: as características dos casos são semelhantes à amostra do principal estudo nacional sobre o uso de crack no Brasil: sexo masculino, cerca de 30 anos de idade, com baixa escolaridade, desempregados, usuários de múltiplas substâncias psicoativas, consumidores de crack há aproximadamente 8 anos. O índice de massa corporal dos casos foi significativamente mais baixo (p<0.0001). Seis casos (17.65%) apresentaram índice de massa corporal abaixo do normal. Dois casos apresentaram nível de tiamina abaixo dos valores de referência, enquanto os níveis dos controles estavam acima deste limite. Comparando os resultados do primeiro quartil do nível sanguíneo de tiamina dos casos (N= 9; mediana 3.6μg/dL, amplitude interquartil 3.05μg/dL -4.10μg/dL) com o dos controles (N=14, mediana 4.3μg/dL, amplitude interquartil 3.7μg/dL-4.4μg/dL), os casos apresentaram níveis significativamente mais baixos (p=0.024). Os níveis de alumínio dos casos que tiveram as amostras de sangue coletadas até 24h após o último consumo da substância, foram maiores (mediana1.85μg/L, amplitude interquartil0.65-4.425μg/L) que os dos controles (mediana 0.95μg/L, amplitude interquartil 0.7-1.22μg/L), mas esta diferença não atingiu significância estatística (p=0.07). Conclusões: dependentes de crack tem índice de massa corporal menor e estão mais expostos ao alumínio que os controles. Alguns tem deficiência de tiamina, a qual pode levar à encefalopatia de Wernicke e declínio cognitivo. Portanto, tiamina parenteral profilática deve ser considerada para alguns dependentes de crack. / Background: Crack-cocaine is an extremely additive form of cocaine and its compulsive use can last days until exhaustion, driving its users to neglect feeding. Poor feeding may cause thiamine deficiency. In Brazil, crack-cocaine is usually smoked in pipes made of aluminum cans or with aluminum foils. Insufficient brain levels of thiamine plus brain aluminum accumulation, may impair glucose energy metabolism, promoting neurodegeneration and possibly Wernicke’s encephalopathy. Objectives: The aim of this study was to evaluate thiamine and aluminum blood levels in crack-cocaine addicts and compare them to healthy controls. Methods: cross-sectional controlled study, included 35 crack-cocaine addicts and 35 healthy controls, all males, 18 or older. Cases were recruited at the Addiction Unit of Hospital de Clínicas de Porto Alegre or at the Mental Health Emergency IAPI, controls were recruited between people circulating in the outpatient clinic area of Hospital de Clínicas de Porto Alegre. Weight and height were measured and blood samples collected for determination of thiamine diphosphate and aluminum levels. Cases were also submitted to a brief neurological examination. Results: cases characteristics were similar to the sample of the main national study related to crack-cocaine use in Brazil: mainly males, about 30 years old, with low education level, unemployed, multiple drug abusers, consuming crack-cocaine for approximately 8 years. Body mass index was significantly lower in cases (p<0.0001). Six cases (17.65%) had body mass index lower than normal, while no control was below this limit. Two cases presented thiamine levels below the laboratory reference range, while controls were all above this limit. Comparing the lower quartile of thiamine blood levels, cases (3.6 μg/dL) had significantly lower levels of thiamine than controls (4.3μg/dL) (p=0.024). Blood aluminum median of crack-cocaine addicts (1.85μg/L, interquartile range 0.65-4.425μg/L) whose samples were drawn until 24h after last drug consumption was higher than controls (0.95μg/L, interquartile range 0.7-1.22μg/L), but the difference did not achieve statistical significance (p=0.07). Conclusions: Crack-cocaine addicts have lower BMI and are more exposed to aluminum in comparison to healthy controls. Also, some of them have thiamine deficiency which may lead to Wernicke’s encephalopathy and cognitive impairment. Thus, prophylactic parenteral thiamine should be considered to some crack-cocaine addicts.

Cette thèse est composée de deux parties. Dans la première partie, nous proposons une théorie pour l'interaction entre l'apprentissage par renforcement et les processus de régulation homéostatique. En fait, la régulation efficace de l'homéostasie interne et la défendre contre les perturbations a besoin des stratégies comportementales complexes pour obtenir des ressources physiologiquement épuisés. À cet égard, il est essentiel que les processus cérébraux de régulation homéostatique et les processus d'apprentissage associatifs travaillent de concert. Nous proposons une théorie computationnelle normative pour régulation homéostatique par l'apprentissage associatif, où la stabilité physiologique et l'acquisition de récompense s'avèrent les mêmes objectifs, réalisables simultanément. En théorie, le cadre résout la question de longue date de la façon dont le comportement manifeste est modulée par l'état interne, et comment les animaux apprennent à agir de manière prédictive pour empêcher des défis homéostasie potentiels (répondre par anticipation). Il fournit en outre une explication normative pour choix intertemporel, aversion au risque, la concurrence entre les systèmes de motivation, et le manque de motivation pour l'injection intraveineuse de produits alimentaires. Neurobiologiquement, la théorie suggère une explication pour le rôle de l'interaction par orexine entre les circuits hypothalamiques et les noyaux dopaminergiques du mésencéphale, comme une interface entre les états internes et les comportements motivés. Dans la deuxième partie de la thèse, nous utilisons le modèle présenté dans la première partie, comme base du développement d'une théorie de la dépendance à la cocaïne. Nous soutenons que la dépendance à la cocaïne provient du système de régulation homéostatique être détourné par les effets pharmacologiques de la cocaïne sur le cerveau. Nous démontrons que le modèle réussit à expliquer une variété des aspects comportementaux et neurobiologiques de la dépendance à la cocaïne , à savoir la grandissant de l’administration de cocaine sous les conditions de long accès a cocaïne, fonction dose-réponse pour la cocaïne , rechute à l'addiction à la cocaïne provoquée par amorçage, et l'interaction entre la disponibilité du récepteur de la dopamine D2 et dépendance à la cocaïne. / This thesis is composed of two parts. In the first part, we propose a theory for interaction between reinforcement learning and homeostatic regulation processes. In fact, efficient regulation of internal homeostasis and defending it against perturbations requires complex behavioral strategies to obtain physiologically-depleted resources. In this respect, it is essential that brains homeostatic regulation and associative learning processes work in concert. We propose a normative computational theory for homeostatically-regulated reinforcement learning (HRL), where physiological stability and reward acquisition prove to be identical objectives achievable simultaneously. Theoretically, the framework resolves the long-standing question of how overt behavior is modulated by internal state, and how animals learn to predictively act to preclude prospective homeostatic challenges (anticipatory responding). It further provides a normative explanation for temporal discounting of reward, and accounts for risk-aversive behavior, competition between motivational systems, taste-induced overeating, and lack of motivation for intravenous injection of food. Neurobiologically, the theory suggests a computational explanation for the role of orexin-based interaction between the hypothalamic circuitry and the midbrain dopaminergic nuclei, as an interface between internal states and motivated behaviors. In the second part of the thesis, we use the HRL model presented in the first part, as the cornerstone for developing an Allostatic Reinforcement Learning (ARL) theory of cocaine addiction. We argue that cocaine addiction arises from the HRL system being hijacked by the pharmacological effects of cocaine on the brain. We demonstrate that the model can successfully capture a wide range of behavioral and neurobiological aspects of cocaine addiction, namely escalation of cocaine self-administration under long- but not short-access conditions, U-shaped dose-response function for cocaine, priming-induced reinstatement of cocaine seeking, and interaction between dopamine D2 receptor availability and cocaine seeking.