A doença hepática gordurosa não alcoólica (DHGNA) é definida pelo acúmulo excessivo de gordura nos hepatócitos sem ingestão significativa de álcool. Essa condição é associada à obesidade e a síndrome metabólica (SM) e é considerada um grave problema de saúde pública global. A DHGNA engloba a esteatose pura e a esteatohepatite, esta última caracterizada pela presença de inflamação e balonização dos hepatócitos, com ou sem formação de fibrose com potencial para evolução para formas mais graves como cirrose e carcinoma hepatocelular. Estudos atuais divergem sobre a relação entre a deficiência da vitamina D e a gravidade da DHGNA. O objetivo foi verificar se há associação entre níveis séricos de vitamina D, citocinas relacionadas ao processo inflamatório (IL-6, IL-10 e TNF-?), presença de componentes da SM e a prevalência e a gravidade da DHGNA. Metodologia Estudo transversal que incluiu 40 pacientes do sexo feminino, obesas (IMC>30kg/m²) e com idade superior a 18 anos submetidas e biópsia hepática e obtiveram diagnostico de DHGNA. Foram coletados dados referentes a características clínicas, parâmetros antropométricos e de gordura corporal. Adicionalmente, foram avaliados parâmetros clínicos de SM e dados bioquímicos relacionados à lesão hepática além de dosagem de 25(OH)D e níveis séricos de citocinas. Um grupo controle com 37 indivíduos saudáveis do sexo feminino, não obesas (IMC<30kg/m²), com idade média de 41 anos, foi usado como controle de vitamina D sérica. Resultados Dos 40 pacientes incluídos, 25 tinham esteatose pura e 15 esteatohepatite. A prevalência de insuficiência de vitamina D foi de 70%. Os valores séricos de vitamina D não foram diferentes quando comparados ao grupo controle saudável e comparando-se esteatose e esteatohepatite. Níveis de vitamina D e de citocinas não apresentaram relação com os parâmetros histopatológicos de lesão hepática, exceto a presença de balonização que foi associada a maiores valores de vitamina D. Níveis séricos de vitamina D correlacionaram-se negativamente com o IMC. Níveis séricos de citocinas não foram associados com a gravidade da DHGNA. O escore NAS e o grau de balonização dos hepatócitos foram maiores em pacientes que apresentaram SM. Conclusões Apesar da alta prevalência de insuficiência de vitamina D, níveis séricos de vitamina D e citocinas não foram associados com presença ou gravidade da DHGNA em pacientes obesas do sexo feminino submetidas à cirurgia bariátrica. Balonização dos hepatócitos foi o único parâmetro histopatológico de gravidade de lesão hepática associado com níveis séricos mais altos de vitamina D. SM foi associada a parâmetros de maior gravidade de lesão hepática. / Nonalcoholic fatty liver disease (NAFLD) is defined by excessive fat accumulation in hepatocytes without significant alcohol intake and is associated with obesity and metabolic syndrome. NAFLD is one of the most common causes of chronic liver disease and it is considered a global public health problem. NAFLD includes pure steatosis and steatohepatitis; the last been characterized by the presence of inflammation and hepatocytes ballooning with or without fibrosis and with potential to evolve to more severe forms as cirrhosis and hepatocelular carcinoma. Current studies diverge on the relationship between vitamin D deficiency and the severity of NAFLD. The objective was to assess if there is an association between vitamin D serum levels, cytokines related to inflammation (IL-6, IL-10 and TNF-?) and presence of metabolic syndrome components and the prevalence and severity of NAFLD. Methods Cross-sectional study of 40 obese (BMI > 30kg/m²) female patients above 18 years who underwent hepatic biopsy during bariatric surgery to diagnose NAFLD and assess the degree of liver damage. Clinical data, anthropometric parameters and body fat were collected. In addition, clinical parameters of metabolic syndrome were evaluated and biochemical data relating to liver injury beyond 25(OH)D and serum cytokines. A control group with 37 healthy non obese females, mean age 41 was used as a controls for serum vitamin D. Results Among 40 NAFLD patients 25 had pure steatosis and 15 steatohepatitis. Prevalence of vitamin D insufficiency was 70%. No difference was observed in vitamin D levels comparing healthy control group and NAFLD or comparing steatosis and steatohepatitis. No relationship was observed between vitamin D or cytokine levels with histopathology parameters of liver injury. Higher levels of vitamin D were associated with cellular ballooning .Vitamin D levels negatively correlated with BMI. Serum cytokine levels were not associated with the severity of NAFLD. The NAS score and the ballooning degree were higher in patients with metabolic syndrome. Conclusions Despite high prevalence of vitamin D insufficiency, serum vitamin D and cytokines were not associated with the presence or severity of NAFLD in obese female patients undergoing bariatric surgery. Ballooning was the only histological parameter of liver damage associated with higher serum levels of vitamin D. Metabolic syndrome was associated with parameters of higher severity of NAFLD.

Au cours de l'obésité, l'excès de lipides circulants, est stocké dans les organes périphériques, principalement dans le foie. Ce stockage ectopique de lipide peut avoir, à long terme, des conséquences délétères sur le métabolisme glucidique. Au long cours, l'excès de lipides hépatiques peut conduire au développement de stéatopathies métaboliques pouvant évoluer vers la cirrhose et le cancer du foie. Dans l'hépatocyte, le métabolisme et l'homéostasie lipidique sont finement régulés par la balance entre la synthèse (LDN) et l'utilisation (ß-oxydation) des lipides. Ces deux voies métaboliques sont sous le contrôle de plusieurs facteurs de transcriptions comme ChREBP, SREBP1 PPARƴ ou PPARa. La compaction et l'accessibilité de la chromatine sont des éléments cruciaux pour la régulation indirecte de l'activité de ces facteurs de transcription. Dans le noyau, la compaction de l'ADN est régulée par les histones mais aussi par les protéines High Mobility Group (HMG). Parmi la famille des protéines HMG, la protéine High Mobility Group box 1 (HMGB1), principalement localisée dans le noyau, est capable de réguler de façon indirecte la transcription de gènes dans de nombreux tissus. En plus de son rôle nucléaire, HMGB1 peut être activement sécrétée par les cellules innées au cours de phénomènes inflammatoires aigus. Chez la souris, la délétion totale de cette protéine entraine une hypoglycémie périnatale létale. De plus, chez la souris, les concentrations circulantes d'HMGB1 sont augmentées lors d'un stress métabolique induit par un régime hyper-lipidique (HFD). Tous ces résultats suggèrent un rôle d'HMGB1 dans le métabolisme hépatique et énergétique ainsi que dans les processus inflammatoires de bas-bruits associés au stress métabolique. [...] / During obesity, the excess of circulating lipids, are stored in the peripheral organs, and mainly in the liver. This ectopic storage of lipids may have long-term deleterious consequences on carbohydrate metabolism. Over time, excess of intra-hepatic lipids can lead to the development of steatohepatitis that can evolve to cirrhosis and liver cancer. In the hepatocyte, lipid homeostasis is finely regulated by the balance between synthesis (de novo lipogenesis-DNL) and degradation (ß-oxidation) of lipids. These two metabolic pathways are under the control of several transcription factors like ChREBP, SREBP1, PPARƴ or PPARa. The compaction and accessibility of chromatin are crucial parameters, which regulate the activity of these transcription factors. In the nucleus, the compaction of DNA is regulated by histones but also by High Mobility Group (HMG) proteins. Among the HMG protein family, High Mobility Group box 1 protein (HMGB1), mainly located in the nucleus, is able to indirectly regulate gene transcription in many tissues. In addition to its nuclear role, HMGB1 can be actively secreted by innate immunes cells during acute inflammatory reactions. In mice, the global deletion of Hmgb1 gene leads to perinatal lethality due to a severe hypoglycemia. Moreover, preliminary data from our laboratory show that circulating concentrations of HMGB1 are increased in mice subjected to high fat diet (HFD). All these results support a role of HMGB1 in hepatic and energetic metabolism but also in tissue-low grade inflammation related to metabolic stress. [...]

Post translational modifications in histone proteins are transmissible changes that are not coded for in the DNA sequence itself but have a significant affect in the control of gene expression. Eukaryotic transcription is a regulated process, and acetylation plays a major role in this regulation. Deranged equilibrium of histone acetylation can lead to alteration in chromatin structure and transcriptional dysregulation of genes that are involved in the control of proliferation, cell-cycle progression, differentiation and or apoptosis. Evidence shows that high glucose conditions mimicking diabetes can increase histone acetylation and augment the inflammatory gene expression. Recent advances also highlight the involvement of altered histone acetylation in gastrointestinal carcinogenesis or hyperacetylation in amelioration of experimental colitis. However, the role of histone acetylation under obesity conditions is not yet known. Therefore in the present study, western blot analysis in the liver of Zucker obese versus lean rats was performed to determine the pattern and level of H3 and H4 acetylation (both in nuclear and homogenate fractions) at specific lysine (K) in pathological state of hepatic steatosis The same technique was also applied in the liver of obese rats fed higher amounts of vitamin B6 (OH) versus those fed normal amounts of vitamin B6 (ON) to assess if hyper-acetylation can be a protective response to hepatic steatosis. In both experimental models, it was also of interest to elucidate the expression of anti- and pro- apoptotic factor Bcl-2 and Bax in respect to histone acetylation. It was observed that, in liver homogenate fractions in control animals (LC/OC), there was a higher level of histone H3 acetylation at (K9, K14) and H4 acetylation at K5 in the obese animals. In contrast, the nuclear level of H3 and H4 acetylation at the same lysine residues was considerably higher in the lean and lower in the obese animals. Obese animals contained lower liver preneoplastic lesions as well as liver weight as a result of higher amounts of vitamin B6, had significantly higher H3 acetylation at K9 and K14 and H4 acetylation at K5, in both homogenate and nuclear fractions. However, histone acetylation was not detected for histone H4 at lysine 12 (K12) in either control group (LC/OC) or obese with different B6 diet group (OH/ON). Nevertheless, global histone H3 and H4 acetylation in both homogenate and nuclear fractions, was slightly higher in the lean rats and obese rats fed higher amounts of B6. By using the western blot technique, the level of anti- and pro- apoptotic Bcl-2 and Bax were also evaluated. The moderately higher level expression of anti-apoptotic Bcl2 protein was found in lean animals, whereas the expression of pro-apoptotic Bax was significantly higher in obese animals. Furthermore, anti-apoptotic Bcl2 protein expression was slightly higher in the obese rats fed normal amounts of B6 diet; but, pro-apoptotic Bax was higher in the obese rats fed higher amounts of vitamin B6. This is the first study which shows that hyperacetylation of histones in liver nuclei can be correlated with amelioration of hepatic steatotis. Histone acetylation and B6 rich diet might be involved in the regulation of biological availability of key apoptotic proteins, which, in turn, can possibly modify the severity of the disease.

Post translational modifications in histone proteins are transmissible changes that are not coded for in the DNA sequence itself but have a significant affect in the control of gene expression. Eukaryotic transcription is a regulated process, and acetylation plays a major role in this regulation. Deranged equilibrium of histone acetylation can lead to alteration in chromatin structure and transcriptional dysregulation of genes that are involved in the control of proliferation, cell-cycle progression, differentiation and or apoptosis. Evidence shows that high glucose conditions mimicking diabetes can increase histone acetylation and augment the inflammatory gene expression. Recent advances also highlight the involvement of altered histone acetylation in gastrointestinal carcinogenesis or hyperacetylation in amelioration of experimental colitis. However, the role of histone acetylation under obesity conditions is not yet known. Therefore in the present study, western blot analysis in the liver of Zucker obese versus lean rats was performed to determine the pattern and level of H3 and H4 acetylation (both in nuclear and homogenate fractions) at specific lysine (K) in pathological state of hepatic steatosis The same technique was also applied in the liver of obese rats fed higher amounts of vitamin B6 (OH) versus those fed normal amounts of vitamin B6 (ON) to assess if hyper-acetylation can be a protective response to hepatic steatosis. In both experimental models, it was also of interest to elucidate the expression of anti- and pro- apoptotic factor Bcl-2 and Bax in respect to histone acetylation. It was observed that, in liver homogenate fractions in control animals (LC/OC), there was a higher level of histone H3 acetylation at (K9, K14) and H4 acetylation at K5 in the obese animals. In contrast, the nuclear level of H3 and H4 acetylation at the same lysine residues was considerably higher in the lean and lower in the obese animals. Obese animals contained lower liver preneoplastic lesions as well as liver weight as a result of higher amounts of vitamin B6, had significantly higher H3 acetylation at K9 and K14 and H4 acetylation at K5, in both homogenate and nuclear fractions. However, histone acetylation was not detected for histone H4 at lysine 12 (K12) in either control group (LC/OC) or obese with different B6 diet group (OH/ON). Nevertheless, global histone H3 and H4 acetylation in both homogenate and nuclear fractions, was slightly higher in the lean rats and obese rats fed higher amounts of B6. By using the western blot technique, the level of anti- and pro- apoptotic Bcl-2 and Bax were also evaluated. The moderately higher level expression of anti-apoptotic Bcl2 protein was found in lean animals, whereas the expression of pro-apoptotic Bax was significantly higher in obese animals. Furthermore, anti-apoptotic Bcl2 protein expression was slightly higher in the obese rats fed normal amounts of B6 diet; but, pro-apoptotic Bax was higher in the obese rats fed higher amounts of vitamin B6. This is the first study which shows that hyperacetylation of histones in liver nuclei can be correlated with amelioration of hepatic steatotis. Histone acetylation and B6 rich diet might be involved in the regulation of biological availability of key apoptotic proteins, which, in turn, can possibly modify the severity of the disease.

Objective: Glucagon-like peptide-1 receptor (GLP-1R) agonists have been shown to reduce atherosclerosis in non-diabetic mice. We hypothesized that treatment with GLP-1R agonists would reduce the development of atherosclerosis in diabetic Apoe-/- mice. Results: Exendin-4 treatment (10 nmol/kg/day) of high-fat diet-induced glucose-intolerant mice for 22 weeks did not significantly reduce oral glucose tolerance (P=0.62) or HbA1c (P=0.85), and did not reduce plaque size at the aortic sinus (P = 0.35). Taspoglutide treatment for 12 weeks (0.4-mg tablet/month) of diabetic mice reduced body weight (P<0.05), food intake (P<0.05), oral glucose tolerance (P<0.05), intrahepatic triglycerides (P<0.05) and cholesterol (P<0.001), and plasma IL-6 levels (P<0.01); increased insulin:glucose (P<0.05); and unaltered oral lipid tolerance (P=0.21), plasma triglycerides (P=0.45) or cholesterol (P=0.92). Nonetheless, taspoglutide unaltered aortic atherosclerosis (P=0.18, sinus; P=0.19, descending aorta) or macrophage infiltration (P=0.45, sinus; P=0.26, arch). Conclusions: GLP-1R activation in either glucose-intolerant or diabetic mice does not significantly modify the development of atherosclerosis.

Objective: Glucagon-like peptide-1 receptor (GLP-1R) agonists have been shown to reduce atherosclerosis in non-diabetic mice. We hypothesized that treatment with GLP-1R agonists would reduce the development of atherosclerosis in diabetic Apoe-/- mice. Results: Exendin-4 treatment (10 nmol/kg/day) of high-fat diet-induced glucose-intolerant mice for 22 weeks did not significantly reduce oral glucose tolerance (P=0.62) or HbA1c (P=0.85), and did not reduce plaque size at the aortic sinus (P = 0.35). Taspoglutide treatment for 12 weeks (0.4-mg tablet/month) of diabetic mice reduced body weight (P<0.05), food intake (P<0.05), oral glucose tolerance (P<0.05), intrahepatic triglycerides (P<0.05) and cholesterol (P<0.001), and plasma IL-6 levels (P<0.01); increased insulin:glucose (P<0.05); and unaltered oral lipid tolerance (P=0.21), plasma triglycerides (P=0.45) or cholesterol (P=0.92). Nonetheless, taspoglutide unaltered aortic atherosclerosis (P=0.18, sinus; P=0.19, descending aorta) or macrophage infiltration (P=0.45, sinus; P=0.26, arch). Conclusions: GLP-1R activation in either glucose-intolerant or diabetic mice does not significantly modify the development of atherosclerosis.

Despite inconsistent results in the literature, high protein diets are being promoted for the management of metabolic syndrome parameters primarily due to their proposed favorable effects on weight loss. Therefore, lean and fa/fa Zucker rats were given normal and high protein diets with varying protein sources for 12 weeks. A high protein diet with a mixture of animal and plant protein sources was the most effective for improving metabolic syndrome parameters, specifically insulin resistance and hepatic steatosis. A high protein soy diet was the second most effective diet, while a high protein casein diet demonstrated no benefits compared to the other two high protein diets and minimal benefits compared to a normal protein casein diet. Interestingly, high protein diets did not affect body weight regardless of protein source. These findings suggest that the source of protein within a high protein diet is critical for improving metabolic syndrome parameters and that improvements can be observed independent of weight loss.

p. 1-79 / Submitted by Antonio Geraldo Couto Barreto (ppgms@ufba.br) on 2013-10-02T17:02:51Z No. of bitstreams: 1 TESE_Consuêlo Padilha-1.pdf: 9442449 bytes, checksum: 72ab1d2cb912c235e58236ec944e7b16 (MD5) / Approved for entry into archive by Patricia Barroso (pbarroso@ufba.br) on 2013-10-30T19:36:47Z (GMT) No. of bitstreams: 1 TESE_Consuêlo Padilha-1.pdf: 9442449 bytes, checksum: 72ab1d2cb912c235e58236ec944e7b16 (MD5) / Made available in DSpace on 2013-10-30T19:36:47Z (GMT). No. of bitstreams: 1 TESE_Consuêlo Padilha-1.pdf: 9442449 bytes, checksum: 72ab1d2cb912c235e58236ec944e7b16 (MD5) Previous issue date: 2013 / A Doença Hepática Gordurosa Não Alcoólica (DHGNA) representa a causa mais comum de doença do fígado na atualidade. Está associada com síndrome metabólica e, mais recentemente, às doenças cardiovasculares. Objetivo: avaliar a associação entre DHGNA e doença arterial coronariana (DAC) e os fatores preditivos desta associação em indivíduos submetidos à cineangiocoronariografia (CAG). Metodologia: Foi realizado estudo transversal, que avaliou indivíduos submetidos à CAG com suspeita de DAC. Os pacientes realizaram avaliação clínico–laboratorial e ultrassonografia abdominal (USAB). Critérios para DAC: presença de lesão obstrutiva em artérias coronárias epicárdicas ou seus principais ramos. Critérios para DHGNA: presença de esteatose na USAB; ingestão alcoólica ≤20 g/dia; ausência de outras doenças hepáticas. As variáveis contínuas foram avaliadas pelos testes t de Student ou teste de Mann-Whitney e as categóricas pelo teste do qui-quadrado com nível de significância (p) < 0,05. Análise de regressão mediu a força da relação entre os fatores de risco e a presença concomitante de DAC e DHGNA. Resultados: Foram estudados 244 pacientes com média de idade de 61,5±9,3 anos. A DAC foi observada em 63,5%, e a DHGNA, em 42,2% dos pacientes. Aqueles com DAC eram, predominantemente, do gênero masculino (p<0,01); diabéticos (p<0,05) e tabagistas (p=0,045), e 43,9% deles tinham DHGNA. A DHGNA esteve associada à DM2, resistência insulínica, síndrome metabólica, obesidade central, índice de massa corpórea, triglicérides e alanina aminotransferase (p<0,05). A ocorrência concomitante de DAC e DHGNA foi positivamente correlacionada a sobrepeso/obesidade e HOMA-IR ≥3,0. Conclusões: A amostra teve elevada frequência de ambas, DAC e DHGNA; DHGNA foi mais elevada em pacientes com DAC, porém não houve associação estatisticamente significante entre as duas doenças; pacientes com associação DAC e DHGNA apresentavam sobrepeso/obesidade, e resistência insulínica. Os resultados sugerem a relevância clínica de investigar a DHGNA em pacientes com DAC, no sentido de diminuir a morbimortalidade desses pacientes. / Salvador

Introdução: A doença hepática alcóolica (DHA) e a doença hepática gordurosa não alcóolica (DHGNA) estão entre as principais causas de morte por doenças hepáticas no mundo. Apesar das etiologias distintas, sendo a DHA causada pelo consumo excessivo de álcool e a DHGNA por dieta inadequada e sedentarismo, apresentam curso de doença semelhante, que pode evoluir de esteatose, para esteato-hepatite, fibrose, cirrose e carcinoma hepatocelular. Tanto a DHA quanto a DHGNA estão relacionadas à disbiose, aumento de permeabilidade intestinal, inflamação e dano hepático. Entretanto, ainda não está claro se a doença hepática precede as alterações no epitélio intestinal ou se é o aumento da permeabilidade que promove o dano hepático. Objetivo: Avaliar a expressão gênica de Tight Junctions em modelo de DHA e DHGNA em zebrafish (Danio rerio). Métodos: No modelo de DHA, os peixes foram divididos em dois grupos: Etanol (n=30), expostos a 0,5% de etanol por 28 dias e controle (n=30). No modelo de DHGNA, os peixes foram divididos também em dois grupos: Frutose (n=24), expostos à frutose 6% durante 2 horas por 14 dias e controle (n=24). Ao término dos experimentos os animais foram eutanasiados e coletados fígados, para avaliação histológica por coloração hematoxilina-eosina (HE) e de esteatose por Oil Red, e intestinos para avaliação da expressão gênica dos marcadores de permeabilidade intestinal cldnC, cldn15a, cldn15b e f11r por Real Time qPcr. Resultados: Tanto os animais expostos ao álcool quanto à frutose apresentaram esteatose hepática por coloração HE e Oil Red quando comparados aos seus respectivos controles, sem sinais de infiltrados inflamatórios e de fibrose hepática à microscopia óptica. Não houve diferença significativa na expressão gênica das tight junctions intestinais, tanto para a DHA quanto DHGNA (p  0,05). Conclusão: Os resultados sugerem que em estágios iniciais de DHA e DHGNA não ocorre alteração da permeabilidade intestinal, e que possivelmente o dano hepático precede o dano intestinal. / Introduction: Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are among the leading causes of death from liver disease worldwide. Despite the different etiologies, ALD is caused by excessive alcohol consumption and NAFLD is due to inadequate diet and sedentary lifestyle, they have a similar disease course, which can progress from steatosis to steatohepatitis, fibrosis, cirrhosis and hepatocellular carcinoma. Both ALD and NAFLD are related to dysbiosis, increased gut permeability, inflammation, and liver damage. However, it is not yet clear whether liver disease precedes changes in the intestinal epithelium or whether it is the increased permeability that promotes liver damage. Objective: To evaluate the gene expression of tight junctions in ALD and NAFLD models in zebrafish (Danio rerio). Methods: In the ALD model, fish were divided into two groups: Ethanol (n=30), exposed to 0.5% ethanol for 28 days and control (n=30). In the NAFLD model, fish were also divided into two groups: Fructose (n=24), exposed to 6% fructose for 2 hours for 14 days and control (n=24). At the end of the experiments the animals were euthanized and livers were collected for histological evaluation by hematoxylin-eosin (HE) staining and steatosis by oil red staining and intestines for evaluation of the gene expression of gut permeability markers cldnC, cldn15a, cldn15b and f11r by Real Time qPcr. Results: Both animals exposed to alcohol and fructose presented hepatic steatosis by HE and Oil Red staining when compared to their respective controls, without signs of inflammatory infiltrates under optical microscopy. There was no significant difference in the gene expression of the tight junctions for both ALD and NAFLD (p0.05) Conclusion: The results suggest that in the early stages of ALD and NAFLD there are no changes in intestinal tight junctions, and that possibly liver damage precedes intestinal damage.

A doença hepática gordurosa não alcoólica (DHGNA) é definida pelo acúmulo excessivo de gordura nos hepatócitos sem ingestão significativa de álcool. Essa condição é associada à obesidade e a síndrome metabólica (SM) e é considerada um grave problema de saúde pública global. A DHGNA engloba a esteatose pura e a esteatohepatite, esta última caracterizada pela presença de inflamação e balonização dos hepatócitos, com ou sem formação de fibrose com potencial para evolução para formas mais graves como cirrose e carcinoma hepatocelular. Estudos atuais divergem sobre a relação entre a deficiência da vitamina D e a gravidade da DHGNA. O objetivo foi verificar se há associação entre níveis séricos de vitamina D, citocinas relacionadas ao processo inflamatório (IL-6, IL-10 e TNF-?), presença de componentes da SM e a prevalência e a gravidade da DHGNA. Metodologia Estudo transversal que incluiu 40 pacientes do sexo feminino, obesas (IMC>30kg/m²) e com idade superior a 18 anos submetidas e biópsia hepática e obtiveram diagnostico de DHGNA. Foram coletados dados referentes a características clínicas, parâmetros antropométricos e de gordura corporal. Adicionalmente, foram avaliados parâmetros clínicos de SM e dados bioquímicos relacionados à lesão hepática além de dosagem de 25(OH)D e níveis séricos de citocinas. Um grupo controle com 37 indivíduos saudáveis do sexo feminino, não obesas (IMC<30kg/m²), com idade média de 41 anos, foi usado como controle de vitamina D sérica. Resultados Dos 40 pacientes incluídos, 25 tinham esteatose pura e 15 esteatohepatite. A prevalência de insuficiência de vitamina D foi de 70%. Os valores séricos de vitamina D não foram diferentes quando comparados ao grupo controle saudável e comparando-se esteatose e esteatohepatite. Níveis de vitamina D e de citocinas não apresentaram relação com os parâmetros histopatológicos de lesão hepática, exceto a presença de balonização que foi associada a maiores valores de vitamina D. Níveis séricos de vitamina D correlacionaram-se negativamente com o IMC. Níveis séricos de citocinas não foram associados com a gravidade da DHGNA. O escore NAS e o grau de balonização dos hepatócitos foram maiores em pacientes que apresentaram SM. Conclusões Apesar da alta prevalência de insuficiência de vitamina D, níveis séricos de vitamina D e citocinas não foram associados com presença ou gravidade da DHGNA em pacientes obesas do sexo feminino submetidas à cirurgia bariátrica. Balonização dos hepatócitos foi o único parâmetro histopatológico de gravidade de lesão hepática associado com níveis séricos mais altos de vitamina D. SM foi associada a parâmetros de maior gravidade de lesão hepática. / Nonalcoholic fatty liver disease (NAFLD) is defined by excessive fat accumulation in hepatocytes without significant alcohol intake and is associated with obesity and metabolic syndrome. NAFLD is one of the most common causes of chronic liver disease and it is considered a global public health problem. NAFLD includes pure steatosis and steatohepatitis; the last been characterized by the presence of inflammation and hepatocytes ballooning with or without fibrosis and with potential to evolve to more severe forms as cirrhosis and hepatocelular carcinoma. Current studies diverge on the relationship between vitamin D deficiency and the severity of NAFLD. The objective was to assess if there is an association between vitamin D serum levels, cytokines related to inflammation (IL-6, IL-10 and TNF-?) and presence of metabolic syndrome components and the prevalence and severity of NAFLD. Methods Cross-sectional study of 40 obese (BMI > 30kg/m²) female patients above 18 years who underwent hepatic biopsy during bariatric surgery to diagnose NAFLD and assess the degree of liver damage. Clinical data, anthropometric parameters and body fat were collected. In addition, clinical parameters of metabolic syndrome were evaluated and biochemical data relating to liver injury beyond 25(OH)D and serum cytokines. A control group with 37 healthy non obese females, mean age 41 was used as a controls for serum vitamin D. Results Among 40 NAFLD patients 25 had pure steatosis and 15 steatohepatitis. Prevalence of vitamin D insufficiency was 70%. No difference was observed in vitamin D levels comparing healthy control group and NAFLD or comparing steatosis and steatohepatitis. No relationship was observed between vitamin D or cytokine levels with histopathology parameters of liver injury. Higher levels of vitamin D were associated with cellular ballooning .Vitamin D levels negatively correlated with BMI. Serum cytokine levels were not associated with the severity of NAFLD. The NAS score and the ballooning degree were higher in patients with metabolic syndrome. Conclusions Despite high prevalence of vitamin D insufficiency, serum vitamin D and cytokines were not associated with the presence or severity of NAFLD in obese female patients undergoing bariatric surgery. Ballooning was the only histological parameter of liver damage associated with higher serum levels of vitamin D. Metabolic syndrome was associated with parameters of higher severity of NAFLD.