PERIPHERAL BLOOD ENDOTOXIN LEVELS ARE NOT ASSOCIATED WITH SMALL INTESTINAL BACTERIAL OVERGROWTH IN NONALCOHOLIC FATTY LIVER DISEASE WITHOUT CIRRHOSIS.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is one of the most common forms of chronic liver disease worldwide. Approximately 20% of individuals with NAFLD develop nonalcoholic steatohepatitis (NASH), which is associated with increased risk of cirrhosis, portal hypertension, and hepatocellular carcinoma. Intestinal microflora, including small intestinal bacterial overgrowth (SIBO), appear to play an important role in the pathogenesis of the disease, as demonstrated in several clinical and experimental studies, by altering intestinal permeability and allowing bacterial endotoxins to enter the circulation. OBJECTIVE: To determine the relationship between SIBO and endotoxin serum levels with clinical, laboratory, and histopathological aspects of NAFLD and the relationship between SIBO and endotoxin serum levels before and after antibiotic therapy. METHODS: Adult patients with a histological diagnosis of NAFLD, without cirrhosis were included. A comprehensive biochemistry panel, lactulose breath test (for diagnosis of SIBO), and serum endotoxin measurement (chromogenic LAL assay) were performed. SIBO was treated with metronidazole 250 mg q8h for 10 days and refractory cases were given ciprofloxacin 500 mg q12h for 10 days. RESULTS: Overall, 42 patients with a histopathological diagnosis of NAFLD were examined. The prevalence of SIBO was 26.2%. Comparison of demographic and biochemical parameters between patients with SIBO and those without SIBO revealed no statistically significant differences, except for use of proton pump inhibitors, which was significantly more frequent in patients with positive breath testing. The presence of SIBO was also associated with greater severity of hepatocellular ballooning on liver biopsy. Although the sample, as a whole, have elevated circulating endotoxin levels, we found no significant differences in this parameter between the groups with and without SIBO. Endotoxin values before and after antibiotic treatment did not differ, even on paired analysis, suggesting absence of any relationship between these factors. Serum endotoxin levels were inversely correlated with HDL levels, and directly correlated with triglyceride levels. CONCLUSION: Serum endotoxin levels did not differ between patients with and without SIBO, nor did these levels change after antibacterial therapy, virtually ruling out the possibility that elevated endotoxinemia in non-cirrhotic patients with NAFLD is associated with SIBO. Presence of SIBO was associated with greater severity of ballooning degeneration on liver biopsy, but not with a significantly higher prevalence of NASH. Additional studies are needed to evaluate the reproducibility and importance of this finding in patients with NAFLD and SIBO.

Níveis de endotoxina no sangue periférico não estão relacionados ao supercrescimento bacteriano intestinal em portadores de doença hepática gordurosa não alcoólica sem cirrose / Peripheral blood endotoxin levels are not associated with small intestinal bacterial overgrowth in nonalcoholic fatty liver disease without cirrhosis

ABSTRACT BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is one of the most common forms of chronic liver disease worldwide. Approximately 20% of individuals with NAFLD develop nonalcoholic steatohepatitis (NASH), which is associated with increased risk of cirrhosis, portal hypertension, and hepatocellular carcinoma. Intestinal microflora, including small intestinal bacterial overgrowth (SIBO), appear to play an important role in the pathogenesis of the disease, as demonstrated in several clinical and experimental studies, by altering intestinal permeability and allowing bacterial endotoxins to enter the circulation. OBJECTIVE: To determine the relationship between SIBO and endotoxin serum levels with clinical, laboratory, and histopathological aspects of NAFLD and the relationship between SIBO and endotoxin serum levels before and after antibiotic therapy. METHODS: Adult patients with a histological diagnosis of NAFLD, without cirrhosis were included. A comprehensive biochemistry panel, lactulose breath test (for diagnosis of SIBO), and serum endotoxin measurement (chromogenic LAL assay) were performed. SIBO was treated with metronidazole 250 mg q8h for 10 days and refractory cases were given ciprofloxacin 500 mg q12h for 10 days. RESULTS: Overall, 42 patients with a histopathological diagnosis of NAFLD were examined. The prevalence of SIBO was 26.2%. Comparison of demographic and biochemical parameters between patients with SIBO and those without SIBO revealed no statistically significant differences, except for use of proton pump inhibitors, which was significantly more frequent in patients with positive breath testing. The presence of SIBO was also associated with greater severity of hepatocellular ballooning on liver biopsy. Although the sample, as a whole, have elevated circulating endotoxin levels, we found no significant differences in this parameter between the groups with and without SIBO. Endotoxin values before and after antibiotic treatment did not differ, even on paired analysis, suggesting absence of any relationship between these factors. Serum endotoxin levels were inversely correlated with HDL levels, and directly correlated with triglyceride levels. CONCLUSION: Serum endotoxin levels did not differ between patients with and without SIBO, nor did these levels change after antibacterial therapy, virtually ruling out the possibility that elevated endotoxinemia in non-cirrhotic patients with NAFLD is associated with SIBO. Presence of SIBO was associated with greater severity of ballooning degeneration on liver biopsy, but not with a significantly higher prevalence of NASH. Additional studies are needed to evaluate the reproducibility and importance of this finding in patients with NAFLD and SIBO.

RESUMO CONTEXTO: A doença hepática gordurosa não alcoólica (DHGNA) é uma das doenças hepáticas crônicas mais comuns em todo o mundo. Aproximadamente 20% dos indivíduos com DHGNA desenvolvem esteato-hepatite não alcoólica (EHNA) que está associada a maior risco de cirrose, hipertensão portal e/ou carcinoma hepatocelular. Alterações da microflora intestinal, incluindo o supercrescimento bacteriano intestinal (SBI), parecem ter um papel importante na patogênese da doença, como demonstrado em estudos clínicos e experimentais, pela alteração da permeabilidade intestinal e permitindo que endotoxinas bacterianas alcancem a circulação sanguínea. OBJETIVO: Determinar a relação entre o SBI e níveis de endotoxina sérica em pacientes não cirróticos com DHGNA, com os aspectos clínicos, laboratoriais e histopatológicos da doença e a relação entre SBI e níveis séricos de endotoxina antes e após tratamento com antibiótico. MÉTODOS: Foram incluídos pacientes maiores de 18 anos e com diagnóstico histológico de DHGNA, sem cirrose. Foram realizados: avaliação bioquímica geral, teste do H2 expirado com lactulose para diagnóstico de SBI e dosagem de endotoxina sérica - ensaio cromogênico para LAL. Para o tratamento do SBI utilizamos o metronidazol 250 mg de 8/8 horas por 10 dias e para os casos de retratamento foi utilizado ciprofloxacino 500 mg de 12/12 horas por 10 dias. RESULTADOS: Incluímos 42 pacientes com diagnóstico histopatológico de DHGNA. A prevalência de SBI foi de 26,2%. Quando comparamos o grupo dos pacientes com SBI com aquele sem SBI e analisamos suas variáveis demográficas e bioquímicas, não encontramos diferença estatisticamente significante entre elas, exceto pela utilização de inibidores de bomba de próton, que foi significantemente mais frequente nos pacientes com teste respiratório positivo. A presença de SBI também esteve associada à maior intensidade de balonização na biópsia hepática, quando comparados àqueles sem SBI. Embora o grupo como um todo apresentasse elevação dos níveis circulantes de endotoxinas, não pudemos encontrar diferenças estatísticas entre os grupos com e sem SBI. Os valores de endotoxinas pré e pós tratamento antibiótico não diferiram entre si, mesmo em análise pareada, sugerindo ausência de relação entre esses fatores. Os níveis de endotoxina sérica apresentaram correlação inversa com os níveis de HDL e correlação direta com os níveis de triglicerídeos. CONCLUSÃO: Níveis de endotoxinas séricas não diferiram entre os pacientes com e sem SBI, e que esses níveis não se modificaram após tratamento medicamentoso da proliferação bacteriana, praticamente excluindo a possibilidade de que os níveis elevados de endotoxemia estejam relacionados à SBI. A presença dessa proliferação bacteriana esteve associada à maior intensidade de balonização na biópsia hepática, mas não à maior prevalência de EHNA entre os portadores de SBI. Estudos complementares são necessários para avaliar a reprodutibilidade e a importância desse achado em portadores de DHGNA com SBI.