Asymptomatic gastric bacterial overgrowth after bariatric surgery: are long-term metabolic consequences possible?

BACKGROUND: Patients with postbariatric bacterial overgrowth were reinvestigated after a follow-up of 15 years. It was hypothesized that systemic associations analogous to those reported for whole gut microbiome would be revealed. METHODS: Patients (n = 37, 70.3 % females, 42.4 ± 9.9 years old, preoperative BMI 53.5 ± 10.6 kg/m(2), current BMI 32.8 ± 10.8 kg/m(2)), all submitted to RYGB on account of morbid obesity, were followed during 176.8 ± 25.7 months. Blood tests included fasting blood glucose, HbA1c, liver and pancreatic enzymes, and lipid fractions. Bacterial overgrowth was diagnosed by quantitative culture of gastric fluid in both the excluded remnant and the gastric pouch, with the help of double-balloon enteroscopy. Absolute counts of aerobes and anaerobes in both gastric reservoirs were correlated with nutritional and biochemical measurements, aiming to identify clinically meaningful associations. RESULTS: Patients denied diarrhea, abdominal pain, weight loss, or other symptoms related to bacterial overgrowth. Biochemical profile including enzymes was also acceptable, indicating a stable condition. Positive correlation of bacterial count in either segment of the stomach was demonstrated for BMI and gamma-glutamyl transferase, whereas negative correlation occurred regarding fasting blood glucose. CONCLUSIONS: An antidiabetic role along with deleterious consequences for weight loss and liver function are possible in such circumstances. Such phenotype is broadly consistent with reported effects for the whole gut microbiome. Prospective controlled studies including molecular analysis of gastrointestinal fluid, and simultaneous profiling of the entire microbiome, are necessary to shed more light on these findings.

Microsatellite instability in solitary and sporadic gastric cancer.

UNLABELLED: Recently, the presence of microsatellite instability (MSI) has been reported in gastric cancer and associated with older age of presentation, distal tumor location, early disease staging, and better overall prognosis. Different characteristics in presentation and in tumor behavior may be explained by different genetic alterations during carcinogenesis of gastric cancer. Identification of specific genetic pathways in gastric cancer may have direct impact on prognosis and selection of treatment strategies. PATIENTS AND METHODS: All 24 patients were treated by radical surgery. Fragments of normal and tumor tissues were extracted from the specimen and stored at -80 degrees C before DNA purification and extraction. PCR amplification utilizing microsatellite markers was performed. Tumors presenting PCR products of abnormal sizes were considered positive for microsatellite instability (MSI+). RESULTS: Five patients (21%) had tumors that were MSI+ in at least 1 marker. In the group of patients with Lauren's intestinal-type gastric carcinoma, 3 had tumors that were MSI+ (23%), while in the group of diffuse-type gastric cancer, 2 patients had tumors that were MSI+ (19%). The mean age of presentation and the male:female ratio was similar in both groups. Tumors that were MSI+ were more frequently located in proximal portion of the stomach compared to microsatellite-stable (MSS) tumors (40% vs. 16%). Although there was a trend of patients with MSI+ tumors towards a proximal gastric tumor location, early staging, and negative lymph node metastasis, there was no statistical significance compared to those with MSS tumors (P >.1). Comparison of overall and disease-free survival between gastric tumors that were MSI+ and those that were MSS found no statistically significant differences (P >.1). CONCLUSIONS: Microsatellite instability is a frequent event in gastric carcinogenesis and shows a trend towards distinct clinical and pathological characteristics of gastric cancer.

Microsatellite instability in solitary and sporadic gastric cancer

A presença de Instabilidade de microsatellites (IMS) tem sido relatada no cancer gastrico e associada a pacientes com idade mais avançada, localização mais distal do tumor, estadios mais precoces e melhor prognostico. Relatamos neste prospectivo estudo envolvendo 24 pacientes com cancer gastrico solitario e esporadico, a incidencia de IMS, sua correlação com parametros epidemiologicos, clinicos e anatomo patológicos e o seu impacto sobre a sobrevida geral e livre de doença. PACIENTES E MÉTODOS: Todos os pacientes haviam sido tratados com cirurgia radical. Fragmentos de tecido normal e tumoral eram extraidos das peças e armazenados a ù80ºC antes da extração e purificação DNA. Realizava-se então a amplificação com PCR utilizando marcadores específicos de microsatelites. Os tumores que apresentavam produtos de amplificação anormais foram considerados positivos para IMS. RESULTADOS: Cinco pacientes (21%) apresentaram Instabilidade de microsatelites (IMS+) com pelo menos um marcador (primer) No grupo de pacientes com adenocarcinomas gástricos do tipo histológico de Lauren, três apresentavam IMS (23%) enquanto no grupo portador de cancar gástrico difuso, dois pacientes mostraram IMS (19%).. Embora haja uma tendência dos pacientes IMS+ apresentarem tumores de localização mais proximal, estadios mais precoces e ausência de metástases linfonodais, não se observou diferenças estatisticamente significativas (p > 0,1). A comparação entre as taxas de sobrevida geral e livre de doença não mostrou significância estatistica (p > 0,1). CONCLUSÕES: IMS é um evento frequente na carcinogese gástrica e pode estar associado a caracteristicas clinicas e anátomo-patológicas do câncer gástrico.