The OLGA-OLGIM staging and the interobserver agreement for gastritis and preneoplastic lesion screening: a cross-sectional study.

Stomach cancer (SC) incidence and mortality are relevant public health issues worldwide. In Colombia, screening for preneoplastic lesions (PNL) and the presence of H. pylori is not routinely performed. Therefore, the aim of this study was to evaluate OLGA-OLGIM staging and the interobserver agreement in gastritis and preneoplastic lesions in patients with gastroduodenal symptoms from Colombia. A cross-sectional study was conducted in 272 patients with gastroduodenal symptoms. Gastric biopsies were taken following the Updated Sydney System with the OLGA-OLGIM classification, and the results were evaluated by two pathologists. Chronic gastritis and PNL were reported in 76% and 24% of the patients, respectively. Furthermore, 25% of the patients with PNL displayed gastric atrophy (GA) and 75% intestinal metaplasia (IM). Agreement in the histopathological reading for IM was good, whereas for OLGA was variable, and for the H. pylori quantity was poor. OLGA-OLGIM stages 0-II were the most frequent (96%), while stage III (4%) and SC (4%) were the least frequent. Age and coffee consumption were associated with a higher prevalence of PNL. This work determined that 4% of the population is at high risk of developing SC and would benefit from follow-up studies. Reinforcement of training programs to improve the agreement in histopathology readings is required.

TAS2R38 polymorphisms, Helicobacter pylori infection and susceptibility to gastric cancer and premalignant gastric lesions.

BACKGROUND: Gastric cancer is worldwide the fourth more common cancer type by incidence, and the third by mortality. We analyzed three missense variants of TAS2R38 gene: rs713598 (A49P), rs1726866 (V262A), and rs10246939 (I296V). These variants and their combination in haplotypes (proline, alanine and valine/tasters or alanine, valine and isoleucine/nontasters) and diplotypes are responsible for individual differences in bitter perception. The single-nucleotide polymorphisms and the related phenotypes are known to be associated with susceptibility to Gram-negative bacterial infections, such as Helicobacter pylori , and with risk of various cancer types. An association between intermediate tasters (as defined by TAS2R38 diplotypes) and increased risk of gastric cancer was reported in a Korean population. METHODS: We analyzed 2616 individuals of Latin American origin, representing the whole spectrum of lesions from gastritis to gastric cancer. RESULTS: Comparing cancer cases vs. noncancers we observed a decrease in risk associated with heterozygous carriers of rs10246939 ( P = 0.006) and rs1726866 ( P = 0.003) when compared with homozygotes of the more common allele. Also, the analysis of diplotypes/phenotypes reflected the same association, with super-tasters showing a borderline increased risk of developing gastric cancer compared to medium-tasters [odds ratio (OR) = 1.63; 95% confidence interval (CI), 1.04-2.56; P = 0.033]. Also, nontasters showed an increased risk when compared to medium-tasters although not reaching statistical significance (OR = 1.58; 95% CI, 0.80-2.87; P = 0.203). We also tested the interactions between the TAS2R38 genotypes and H. pylori cagA status in a subset of samples and found no interaction. CONCLUSION: In conclusion, our results suggest only a modest contribution of TAS2R38 gene genetic variability in gastric cancer etiology.

Genetic polymorphisms in the cag pathogenicity island of Helicobacter pylori and risk of stomach cancer and high-grade premalignant gastric lesions.

Helicobacter pylori (Hp) infects the stomach of about half of the human population and is strongly associated with the risk of gastric cancer (GC) and its premalignant precursors. The cag pathogenicity island (cagPAI) is a region of the Hp genome encoding for key molecular machinery involved in the infection process. Following a sequencing study, we selected 50 genetic polymorphisms located in seven cagPAI genes and tested their associations with the risk of advanced gastric premalignant lesions and GC in 1220 subjects from various Latin American populations showing the whole spectrum of phenotypes from gastritis to GC. We found that three polymorphisms of cagA are associated with the risk of advanced gastric premalignant lesions (incomplete intestinal metaplasia [ie, Type 2 and 3] or dysplasia), and that six polymorphisms located in cagA, cagL and cagI were associated with risk of GC. When corrected for multiple testing none of the associations were statistically significant. However, scores built by integrating the individual polymorphisms were significantly associated with the risk of advanced gastric premalignant lesions and GC. These results have the potential of establishing markers for risk stratification in the general population, in view of targeting Hp eradication to high-risk population groups.

Variations in cag pathogenicity island genes of Helicobacter pylori from Latin American groups may influence neoplastic progression to gastric cancer.

Helicobacter pylori (HP) colonizes the human stomach and induces acute gastritis, peptic ulcer disease, atrophic gastritis, and gastric adenocarcinoma. Increased virulence in HP isolates derives from harboring the cag (cytotoxin-associated genes) pathogenicity island (cagPAI). We analyzed the microvariants in cagPAI genes with the hypothesis that they may play an important role in determining HP virulence. We tested DNAs from cagA positive patients HP isolates; a total of 74 patients with chronic gastritis (CG, N = 37), intestinal metaplasia (IM, N = 21) or gastric cancer (GC, N = 16) from Mexico and Colombia. We selected 520 non-synonymous variants with at least 7.5% frequency in the original sequence outputs or with a minimum of 5 isolates with minor allele. After adjustment for multiple comparisons, no variants were statistically significantly associated with IM or GC. However, 19 non-synonymous showed conventional P-values < 0.05 comparing the frequency of the alleles between the isolates from subjects with gastritis and isolates from subjects with IM or GC; 12 of these showed a significant correlation with the severity of the disease. The present study revealed that several cagPAI genes from Latin American Western HP strains contains a number of non-synonymous variants in relatively high frequencies which could influence on the clinical outcome. However, none of the associations remained statistically significant after adjustment for multiple comparison.

Risk factors for gastric precancerous and cancers lesions in Latin American counties with difference gastric cancer risk.

OBJECTIVE: To evaluate the risk factors associated with pre-neoplastic lesions and gastric cancer in countries with different cancer risk in Latin America. METHODS: 1222 questionnaires of risk factors related to pre-neoplastic lesions and gastric cancer were obtained from patients from Mexico (N = 559), Colombia (N = 461) and Paraguay (N = 202), who were treated at the gastroenterology or oncology service of participant hospitals. In addition, biopsies specimens to establish histological diagnosis and blood to detect IgG antibodies against Helicobacter-pylori (H. pylori) whole-cell antigens and CagA protein using an ELISA were collected. These consisted of 205 gastric cancer, 379 pre-neoplastic (intestinal metaplasia (IM) / atrophic gastritis) and 638 control (normal /non-atrophic gastritis) cases. The odds ratio (OR) and 95% confidence intervals (CI) associated with potential risk factors were estimated by polynomial logistic regression model. RESULTS: Seropositivity to H. pylori was associated with risk of pre-neoplastic lesions, with OR = 1.9 (CI 95% 1.2-2.9; p = 0.006). Grain / cereal intake (OR = 1.6, 95% CI 1.0-2.5 ; p = 0.049) and egg intake (OR = 1.7 95% CI 1.1-2.6 ; p = 0.021) were related to gastric cancer. Among, people who did not developed gastric cancer, smoking more than five cigarette per day had the highest risk of being infected by H. pylori (OR = 1.9; CI 95% 1.1-3.3 ; p = 0.028). CONCLUSION: The present study in Latin American countries confirmed that similar environmental factors such as smoking and grain/cereal consumption were associated with H. pylori infection and its induced gastric lesions as reported in other regions where dominant H. pylori strains differ.

Potential Role of Biofilm Formation in the Development of Digestive Tract Cancer With Special Reference to Helicobacter pylori Infection.

Bacteria are highly social organisms that communicate via signaling molecules and can assume a multicellular lifestyle to build biofilm communities. Until recently, complications from biofilm-associated infection have been primarily ascribed to increased bacterial resistance to antibiotics and host immune evasion, leading to persistent infection. In this theory and hypothesis article we present a relatively new argument that biofilm formation has potential etiological role in the development of digestive tract cancer. First, we summarize recent new findings suggesting the potential link between bacterial biofilm and various types of cancer to build the foundation of our hypothesis. To date, evidence has been particularly convincing for colorectal cancer and its precursor, i.e., polyps, pointing to several key individual bacterial species, such as Bacteroides fragilis, Fusobacterium nucleatum, and Streptococcus gallolyticus subsp. Gallolyticus. Then, we further extend this hypothesis to one of the most common bacterial infection in humans, Helicobacter pylori (Hp), which is considered a major cause of gastric cancer. Thus far, there has been no direct evidence linking in vivo Hp gastric biofilm formation to gastric carcinogenesis. Yet, we synthesize the information to support an argument that biofilm associated-Hp is potentially more carcinogenic, summarizing biological characteristics of biofilm-associated bacteria. We also discuss mechanistic pathways as to how Hp or other biofilm-associated bacteria control biofilm formation and highlight recent findings on Hp genes that influence biofilm formation, which may lead to strain variability in biofilm formation. This knowledge may open a possibility of developing targeted intervention. We conclude, however, that this field is still in its infancy. To test the hypothesis rigorously and to link it ultimately to gastric pathologies (e.g., premalignant lesions and cancer), studies are needed to learn more about Hp biofilms, such as compositions and biological properties of extracellular polymeric substance (EPS), presence of non-Hp microbiome and geographical distribution of biofilms in relation to gastric gland types and structures. Identification of specific Hp strains with enhanced biofilm formation would be helpful not only for screening patients at high risk for sequelae from Hp infection, but also for development of new antibiotics to avoid resistance, regardless of its association with gastric cancer.

Rapid evolution of the Helicobacter pylori AlpA adhesin in a high gastric cancer risk region from Colombia.

To be able to survive, Helicobacter pylori must adhere to the gastric epithelial cells of its human host. For this purpose, the bacterium employs an array of adhesins, for example, AlpA. The adhesin AlpA has been proposed as a major adhesin because of its critical role in human stomach colonization. Therefore, understanding how AlpA evolved could be important for the development of new diagnostic strategies. However, the genetic variation and microevolutionary patterns of alpA have not been described in Colombia. The study aim was to describe the variation patterns and microevolutionary process of alpA in Colombian clinical isolates of H. pylori. The existing polymorphisms, which are deviations from the neutral model of molecular evolution, and the genetic differentiation of the alpA gene from Colombian clinical isolates of H. pylori were determined. The analysis shows that gene conversion and purifying selection have shaped the evolution of three different variants of alpA in Colombia.

Integration, Viral Charge and E2 mRNA Levels in the Progresion of Intraepitelial Cervical Lesions / Integración, carga viral y niveles de arn mensajero de e2 de vph 16 en la progresión de lesiones intraepiteliales cervicales

RESUMEN Entre las lesiones intraepiteliales escamosas cervicales (LIE) es importante distinguir aquellas asociadas con mayor riesgo de cáncer de cuello uterino. El objetivo de este trabajo fue evaluar si los niveles de expresión de E2 del VPH16 en mujeres con LIE y con evidencia de integración viral se asocian con el grado de la lesión. Se analizaron 109 cepillados cervicales positivos para VPH 16 provenientes de 19 mujeres sin LIE, 45 mujeres con LIE de bajo grado (LIEBG) y 45 mujeres con LIE de alto grado (LIEAG). Se cuantificó el número de copias de ARNm de E2 y de los genes E2 y E6 mediante PCR en tiempo real para determinar la carga viral (E6) y la proporción E2/E6 para evaluar la integración viral. Se encontraron frecuencias similares de expresión de E2 en LEIBG y LEIAG 15/45 (33 %), la frecuencia en mujeres sin lesión fue menor 3/19 (15,8 %), todos los casos en los que se observó expresión del gen E2 tenían mezcla de ADN viral episomal e integrado. La carga viral aumentó significativamente a mayor grado de la lesión (ρ =0,049), mientras que la proporción E2/E6 disminuyó (ρ=0,049). El análisis ROC mostró una baja capacidad de los tres parámetros virales para distinguir entre lesiones de bajo y alto grado. En conclusión, aunque las lesiones con presencia de ADN viral mixto e integrado y expresión de E2 podrían estar en menor riesgo de progresión, y la carga viral y la integración se relacionaron con mayor gravedad de la lesión, su valor clínico como biomarcadores de LEIAG es limitado.

ABSTRACT It is important to distinguish among squamous intraepithelial lesions (SIL) those associated with increased risk cervical cancer. Our aim was to evaluate if the expression level of gen E2 in women with SIL and evidence of viral integration is associated to the grade of lesion. Cervical scrapes HPV16 positive from 19 women with normal histology, 45 women with low-grade SIL (LSIL) and 45 women with high-grade SIL (HSIL) were analyzed. Real-time PCR was used to quantify the mRNA of E2 and E2 and E6 genes to calculate viral load (E6) and the ratio E2/E6 to assess viral integration. Similar frequencies of E2 expression were found in LSIL and HSIL15/45 (33 %), the frequency in women without SIL was lower 3/19 (15.8 %), and all cases with E2 gene expression had mixed episomal and integrated viral DNA. The viral load increased significantly with the grade of SIL (ρ= 0.049), while E2/E6 ratio decreased (ρ=0.049). The ROC analysis showed low capacity of the three viral parameters analyzed to distinguish between low and high grade SIL. In conclusion although SIL with mixed and integrated viral DNA with E2 expression could be at lower risk of progression, and viral load and integration were associated with higher severity of the lesion, its clinical value as biomarkers of HSIL is limited.

Phylogenomics of Colombian Helicobacter pylori isolates.

BACKGROUND: During the Spanish colonisation of South America, African slaves and Europeans arrived in the continent with their corresponding load of pathogens, including Helicobacter pylori. Colombian strains have been clustered with the hpEurope population and with the hspWestAfrica subpopulation in multilocus sequence typing (MLST) studies. However, ancestry studies have revealed the presence of population components specific to H. pylori in Colombia. The aim of this study was to perform a thorough phylogenomic analysis to describe the evolution of the Colombian urban H. pylori isolates. RESULTS: A total of 115 genomes of H. pylori were sequenced with Illumina technology from H. pylori isolates obtained in Colombia in a region of high risk for gastric cancer. The genomes were assembled, annotated and underwent phylogenomic analysis with 36 reference strains. Additionally, population differentiation analyses were performed for two bacterial genes. The phylogenetic tree revealed clustering of the Colombian strains with hspWestAfrica and hpEurope, along with three clades formed exclusively by Colombian strains, suggesting the presence of independent evolutionary lines for Colombia. Additionally, the nucleotide diversity of horB and vacA genes from Colombian isolates was lower than in the reference strains and showed a significant genetic differentiation supporting the hypothesis of independent clades with recent evolution. CONCLUSIONS: The presence of specific lineages suggest the existence of an hspColombia subtype that emerged from a small and relatively isolated ancestral population that accompanied crossbreeding of human population in Colombia.

Correction: Rapid evolution of distinct Helicobacter pylori subpopulations in the Americas.

[This corrects the article DOI: 10.1371/journal.pgen.1006546.].

Rapid evolution of distinct Helicobacter pylori subpopulations in the Americas.

For the last 500 years, the Americas have been a melting pot both for genetically diverse humans and for the pathogenic and commensal organisms associated with them. One such organism is the stomach-dwelling bacterium Helicobacter pylori, which is highly prevalent in Latin America where it is a major current public health challenge because of its strong association with gastric cancer. By analyzing the genome sequence of H. pylori isolated in North, Central and South America, we found evidence for admixture between H. pylori of European and African origin throughout the Americas, without substantial input from pre-Columbian (hspAmerind) bacteria. In the US, strains of African and European origin have remained genetically distinct, while in Colombia and Nicaragua, bottlenecks and rampant genetic exchange amongst isolates have led to the formation of national gene pools. We found three outer membrane proteins with atypical levels of Asian ancestry in American strains, as well as alleles that were nearly fixed specifically in South American isolates, suggesting a role for the ethnic makeup of hosts in the colonization of incoming strains. Our results show that new H. pylori subpopulations can rapidly arise, spread and adapt during times of demographic flux, and suggest that differences in transmission ecology between high and low prevalence areas may substantially affect the composition of bacterial populations.

Clinical manifestations of colorectal cancer patients from a large multicenter study in Colombia.

Colorectal cancer (CRC) is a major public health problem, and its incidence is rising in developing countries. However, studies characterizing CRC clinicopathological features in cases from developing countries are still lacking. The goal of this study was to evaluate clinicopathological and demographic features in one of the largest CRC studies in Latin America.The study involved over 1525 CRC cases recruited in a multicenter study in Colombia between 2005 and 2014 as part of ongoing genetic and epidemiological studies. We gathered clinicopathological data such as age at diagnosis, sex, body mass index, tobacco and alcohol consumption, family history of cancer, and tumor features including location, histological type, and stage. Statistical analyses were performed to test the association between age of onset, sex, and clinical manifestations.The average age at CRC diagnosis was 57.4 years, with 26.5% of cases having early-onset CRC (diagnosed by age 50 years). Most cases were women (53.2%; P = 0.009), 49.2% were overweight or obese, 49.1% were regular alcohol drinkers, 52% were smokers/former smokers, and 12.2% reported relatives with cancer. Most tumors in the study were located in the rectum (42.7%), were adenocarcinomas (91.5%), and had advanced stage (T3-T4, 79.8%). Comparisons by sex found that male cases were more likely to be obese (36.5% vs 31.1%; P = 0.001), less likely to have a family history of cancer (9.7% vs 15.3%; P = 0.016), and more likely to have advanced-stage tumors (83.9% vs 76.1%; P = 0.036). Comparisons by age of onset found that early-onset cases were more likely to be women (59.3% vs 51.0%; P = 0.005) and report a family history of cancer (17.4% vs 10.2%; P = 0.001).To our knowledge, our study is the largest report of clinicopathological characterization of Hispanic CRC cases, and we suggest that further studies are needed to understand CRC etiology in diverse Hispanic populations.

Distribución de los genotipos del virus del papiloma humano en mujeres de Bogotá con anomalías en la citología cervicouterina / Genotype distribution of Human Papillomavirus in women from Bogotá with abnormal cervical smear

Objetivos: Determinar la distribución de los genotipos de VPH en mujeres de Bogotá con citología cervicouterina anormal. Métodos: Se colectaron muestras cervicales de 191 mujeres con ASCUS, 236 con lesiones intraepiteliales escamosas de bajo grado (LIEBG) y 116 de alto grado (LIEAG). La tipificación de VPH se realizó usando PCR con iniciadores consenso GP5+/GP6+ y reverse line blot. Resultados: La prevalencia de VPH fue 76,1%. Se observaron infecciones únicas en el 41,4% de las participantes, y coinfecciones en el 34,6%. La frecuencia de VPH según diagnóstico fue: 60,2%, 84,7% y 84,5% en ASCUS, LIEBG y LIEAG. Los VPH-16 y 58 fueron los tipos más frecuentes en los tres grupos, con frecuencias para VPH-16 de 20,4%, 33,9% y 38,8%, y para VPH-58 de 7,3%, 13,6%, 18,1% para ASCUS, LIEBG y LIEAG. En ASCUS y LSIL el tercer tipo en frecuencia fue VPH-56 (6,8% y 11,0%), mientras que en LIEAG fue VPH-18 (10,3%). Las infecciones con tipos virales probablemente oncogénicos y con tipos de bajo riesgo fueron mucho menos frecuentes y en general se presentaron como coinfecciones con tipos de alto riesgo. Conclusiones: Las infecciones con tipos de VPH de alto riesgo fueron las más frecuentes en todas las lesiones estudiadas, el VPH-58 ocupo el segundo lugar en frecuencia, como ha sido reportado en México y en general en Suramérica. El cambio hacia nuevas vacunas profilácticas que incluyan más tipos virales como el VPH-58 puede tener un mayor impacto en la disminución de la incidencia de lesiones preneoplásicas en nuestra región.

Objective: To determine the distribution of HPV genotypes in women from Bogotá with abnormal cervical smear. Methods: Cervical samples were collected from 191 women with ASCUS, 236 with low-grade (LSIL) and 116 with high-grade squamous intraepithelial lesions (HSIL). HPV typing was performed using consensus PCR primers GP5+/GP6 + and reverse line blot. Results: The prevalence of HPV was 76.1%. Unique infections were observed in 41.4% of the participants and co-infections in 34.6%. The frequency of HPV according to diagnosis was: 60.2%, 84.7% and 84.5% in ASCUS, LSIL and HSIL respectively. HPV16 and 58 were the more frequent types in the three groups, HPV16 frequencies were 20.4%, 33.9% and 38.8%, and HPV58 frequencies were 7.3%, 13.6%, and 18,1% for ASCUS, LSIL and HSIL respectively. The third type in frequency in ASCUS and LSIL was HPV56 (6.8% and 11.0%), while in HSIL was HPV18 (10.3%). Infections with probably oncogenic types or with low risk types were much less frequent and generally were observed as co-infections with high-risk types. Conclusions: Infections with high risk HPV types were the most frequent in all studied lesions, VPH-58 ranked second in frequency as has been reported in Mexico and in general in South America. The change to new prophylactic vaccines including more viral types as HPV58 could have a higher impact in reducing the incidence of pre-neoplastic lesions in our region.

Draft Genome Sequence of a Helicobacter pylori Strain Isolated from a Patient with Diffuse Gastritis from a Region of High Cancer Risk in Colombia.

The draft genome sequence of one Colombian Helicobacter pylori strain is presented. This strain was isolated from a patient with diffuse gastritis from Tibaná, Boyacá, a region with high gastric cancer risk.

[Genotyping of Helicobacter pylori virulence factors vacA and cagA in individuals from two regions in Colombia with opposing risk for gastric cancer]. / Genotipificación de los factores de virulencia vacA y cagA de Helicobacter pylori en individuos de dos regiones de Colombia con riesgo opuesto de cáncer gástrico.

INTRODUCTION: The overall prevalence of Helicobacter pylori infection is high in Colombia; however, in the country´s Andean region, gastric cancer rates far surpass those in coastal areas. Helicobacter pylori genotypes cagA positive and vacA s1 and m1 are associated with an increased risk of gastric cancer. OBJECTIVE: To compare the distribution of H. pylori genotypes associated with virulence in two regions in Colombia with opposing risk for gastric cancer. MATERIALS AND METHODS: Four hundred and one gastric antral biopsies were obtained and analyzed from 401 individuals diagnosed with non-atrophic gastritis, atrophic gastritis and intestinal metaplasia: 256 came from the high-risk area cities of Tunja and Bogotá, and 145 from the low-risk area cities of Barranquilla, Santa Marta and Cartagena. Genotyping of virulence genes vacA and cagA was performed by PCR. RESULTS: No difference was observed in the frequency of H. pylori infection between the two areas (77.3% vs 77.9 %, p=non significant, ns). The presence of cagA was higher in the low-risk area (77.9% vs. 69.2 %, p=ns). The vacA s1 allele was also more prevalent in the low-risk area (61.8 % vs 72.0 %, p=ns). The vacA m1 allele was more prevalent in the high-risk area (57.2 % vs 42.8 %, p=ns). The cagA positive s1m1 combination was also more frequent in the low-risk area (48.9% vs 38.9%, p=ns). CONCLUSIONS: The differences in the risk of gastric cancer in these two geographic areas cannot be explained by differences in the prevalence of infection by H. pylori or by differences in the virulence of circulating strains.

Genotipificación de los factores de virulencia vacA y cagA de Helicobacter pylori en individuos de dos regiones de Colombia con riesgo opuesto de cáncer gástrico / Genotyping of Helicobacter pylori virulence factors vacA and cagA in individuals from two regions in Colombia with opposing risk for gastric cancer

Introducción. La prevalencia de infección por Helicobacter pylori es alta en Colombia; en la zona andina las tasas de cáncer gástrico son altas mientras que en las zonas costeras son bajas. Los genotipos de H. pylori cagA positivo y vacA s1 y m1 se asocian con un mayor riesgo de cáncer gástrico. Objetivo. Determinar las diferencias en las frecuencias de los genotipos de H. pylori asociados a virulencia en dos regiones de Colombia con riesgo opuesto de cáncer gástrico. Materiales y métodos. Se analizaron 401 biopsias del antro gástrico provenientes de 401 individuos con diagnóstico de gastritis no atrófica, gastritis atrófica o metaplasia intestinal; 256 se obtuvieron en la zona de alto riesgo (Tunja y Bogotá) y, 145, en la zona de bajo riesgo (Barranquilla, Santa Marta y Cartagena). La genotipificación de los genes de virulencia cagA y vacA se hizo mediante reacción en cadena de la polimerasa (PCR). Resultados. No se observó diferencia en la frecuencia de infección por H. pylori entre las dos zonas (77,3 Vs . 77,9 %, p=no significativo, ns). La presencia de cagA fue mayor en la zona de bajo riesgo (77,9 Vs . 69,2 %, p=ns). El alelo vacA s1 también fue más prevalente en la zona de bajo riesgo (61,8 Vs . 72,0 %, p=ns). El alelo vacA m1 presentó mayor prevalencia en la zona de alto riesgo (57,2 Vs . 42,8 %, p=ns). La combinación cagA positivo s1m1 también fue más frecuente en la zona de bajo riesgo (48,9 Vs . 38,9 %, p=ns). Conclusiones. Las diferencias en el riesgo de cáncer gástrico en estas dos zonas no pueden explicarse por las diferencias en la prevalencia de infección por H. pylori o en la virulencia de las cepas circulantes.

Introduction: The overall prevalence of Helicobacter pylori infection is high in Colombia; however, in the country´s Andean region, gastric cancer rates far surpass those in coastal areas. Helicobacter pylori genotypes cagA positive and vacA s1 and m1 are associated with an increased risk of gastric cancer. Objective: To compare the distribution of H. pylori genotypes associated with virulence in two regions in Colombia with opposing risk for gastric cancer. Materials and methods: Four hundred and one gastric antral biopsies were obtained and analyzed from 401 individuals diagnosed with non-atrophic gastritis, atrophic gastritis and intestinal metaplasia: 256 came from the high-risk area cities of Tunja and Bogotá, and 145 from the low-risk area cities of Barranquilla, Santa Marta and Cartagena. Genotyping of virulence genes vacA and cagA was performed by PCR. Results: No difference was observed in the frequency of H. pylori infection between the two areas (77.3% vs 77.9 %, p=non significant, ns). The presence of cagA was higher in the low-risk area (77.9% vs. 69.2 %, p=ns). The vacA s1 allele was also more prevalent in the low-risk area (61.8 % vs 72.0 %, p=ns). The vacA m1 allele was more prevalent in the high-risk area (57.2 % vs 42.8 %, p=ns). The cagA positive s1m1 combination was also more frequent in the low-risk area (48.9% vs 38.9%, p=ns). Conclusions: The differences in the risk of gastric cancer in these two geographic areas cannot be explained by differences in the prevalence of infection by H. pylori or by differences in the virulence of circulating strains.

Niveles séricos de pepsinógeno y su capacidad diagnóstica de atrofia gástrica en diferentes poblaciones colombianas / Serum pepsinogen levels and gastric atrophy diagnostic capacity in different Colombian populations

Objetivo: Caracterizar los niveles de pepsinógeno y evaluar la capacidad de discriminación del PGI y la relación PGI/PGII para el diagnóstico serológico de atrofia gástrica en diferentes poblaciones colombianas. Materiales y métodos: Participaron 600 sujetos sin sintomatología gástrica y se analizaron 544 muestras de pacientes con sintomatología gástrica provenientes de diferentes poblaciones con riesgos opuestos para cáncer gástrico. A todos los participantes se les tomó muestra de sangre. En los pacientes se obtuvieron biopsias de antro y cuerpo para su diagnóstico inicial de lesiones gastroduodenales. Los niveles de pepsinógeno y la serología de Helicobacter pylori se estimaron con pruebas de ELISA. Los análisis estadísticos incluyeron pruebas de Kruskal-Wallis y Mann-Whitney, curva ROC y valores diagnósticos. Resultados: Los niveles de pepsinógeno en pacientes y sujetos asintomáticos difieren según la zona de riesgo de procedencia. Los niveles de PGI, PGII y PGI/PGII disminuyeron a medida que aumenta la severidad del diagnóstico histológico (p < 0,005), al igual que con el grado de severidad de la atrofia y la localización multifocal (p≤0,001). El PGI ≤86,68 y PGI/PGII ≤3,19 con un área bajo la curva de 0,76 identificó pacientes con atrofia severa multifocal, serología positiva para H. pylori y procedentes de la zona de riesgo alto, con sensibilidad de 77,5% y especificidad de 71,74%. Conclusión: Los resultados sugieren que los niveles de PGI, PGI/PGII conjuntamente con serología H. pylori positiva podrían ser considerados para la detección de atrofia severa en pacientes de la zona de riesgo alto. Se necesita otros estudios en poblaciones de riesgo alto.

Objective: To characterize levels of pepsinogen and evaluate the discrimination ability of pepsinogen I (PGI) and the PGI/ pepsinogen II (PGII) ratio for the serological diagnosis of gastric atrophy in different Colombian populations. Methods: A total 600 subjects without gastric symptoms participated and 544 samples from patients with gastric symptomatology were analyzed from different populations with opposing risks to gastric cancer. A blood sample was taken from all participants; a gastric antrum and body biopsy for the initial diagnosis of gastroduodenal lesions was obtained from the patients. The levels of pepsinogen and Helicobacter pylori serology were estimated with ELISA. Statistical analyses included Kruskal -Wallis and Mann -Whitney test, ROC curve and diagnostic values. Results: The levels of PGI and PGI / PGII differ by risk area of origin. Levels of PGI, PGII and PGI / PGII decreased with increasing severity of histological diagnosis (P < .005), as with the severity of atrophy and multifocal localization (P ≤.001). The PGI ≤ 86.68 and PGI / PGII ≤ 3.19 with an area under the curve of 0.76 identified patients with severe multifocal atrophy, positive serology for H. pylori, and from the high risk area, with a sensitivity of 77.5% and specificity of 71.74%. Conclusion: The results suggest that PGI levels together with PGI / PGII ratios and positive serology for H. pylori could be considered for the detection of severe atrophy in high-risk areas. Further studies are needed in high-risk populations © 2014 Instituto Nacional de Cancerología. Published by Elsevier España, S.L.U. All rights reserved.

Lesiones preneoplásicas gástricas en pacientes colombianos: asociación de polimorfismos genéticos interleucinas 1B-511, 1RN, 10-819, 10-1082, factor de necrosis tumoral-&alpha -308 y anticuerpos inmunoglobulina G hacia cagA de Helicobacter pylori / Pre-cancerous gastric lesions in Colombian patients: association with IL-1B-511, IL-1RN, IL-10-919, IL-10-1082, TNF-&alpha -308 genes polymorphisms, and anti-Helicobacter pylori cagA IgG antibodies

Objetivo: Evaluar la asociación de los polimorfismos de alguna de las citocinas más estudiadas en relación con el cáncer gástrico (IL-1B-511, IL-1RN intron-2-VNTR, TNF-α-308, IL-10-819 e IL-10- 1082) y la presencia de anticuerpos hacia la proteína cagA de Helicobacter pylori con las lesiones preneoplásicas gástricas en pacientes colombianos. Materiales y métodos: Se estudiaron 185 pacientes con lesiones preneoplásicas (gastritis atrófca, metaplasia intestinal y displasia), y 154 controles (gastritis no atrófica), provenientes de hospitales de una zona de riesgo alto y otra de riesgo bajo para cáncer gástrico. Se obtuvieron biopsias gástricas y muestras de sangre; la genotipificación de los polimorfismos se hizo por discriminación alélica usando PCR en tiempo real y por PCR convencional y electroforesis en agarosa (VNTR del intron 2 de IL-1RN); la serología de Helicobacter pylori y Helicobacter pylori cagA se determinó por ELISA. Se utilizó regresión logística multinomial en el análisis estadístico. Resultados: El genotipo IL-1B-511TT (odds ratio = 4,05; intervalo de confianza 95% 1,35-12,10) se asoció a metaplasia intestinal; no se observaron otras asociaciones entre los diferentes polimorfismos y las lesiones preneoplásicas. La infección por Helicobacter pylori cagA positivo se asoció a gastritis atrófica, metaplasia intestinal y displasia (OR = 2,66; 13,70; 40,29, respectivamente). Conclusión: Los resultados sugieren que entre los genotipos proinflamatorios el genotipo IL-1B-511TT estaría asociado a la metaplasia intestinal, y la serología de Helicobacter pylori cagA positivo sería un biomarcador útil para intervenir y prevenir la presencia de lesiones preneoplásicas. Se necesitan otros estudios con población colombiana que evalúen la asociación hallada de IL1B-511 con la metaplasia intestinal.

Objective: To evaluate the relationship of some of the most studied cytokines (IL-1B-511, IL-1RN intron-2-VNTR, TNF-a-308, IL-10-819, and IL-10-1082) with gastric cancer, as well as the presence of anti-Helicobacter pylori cagA IgG antibodies with pre-cancerous lesions in Colombian patients. Materials and methods: A study was conducted on 185 patients with pre-cancerous lesions (atrophic gastritis, intestinal metaplasia and dysplasia), and 154 controls (non-atrophic gastritis), seen in hospitals in a high risk area, and another in a low risk area, for gastric cancer. Gastric biopsy specimens and blood samples were obtained. The genotyping of the polymorphisms was performed by allelic discrimination using real-time PCR, conventional PCR, and agarose electrophoresis (VNTR of IL-1RN intron 2). The serology of Helicobacter pylori and Helicobacter pylori cagA was determined by ELISA. A multinomial logistic regression was used in the statistical analysis. Results: The IL-1B-511TT genotype was associated with intestinal metaplasia (OR=4.05; 95% CI; 1.35-12.10). No other relationships were observed between the different polymorphisms and preimg/revistas/rcc/cancerous lesions. Infection due to a positive Helicobacter pylori cagA was associated with atrophic gastritis, intestinal metaplasia and dysplasia (OR=2.66; 13.70; 40.29, respectively). Conclusion: The results suggest that, among the pro-inflammatory genotypes, the IL-1B-511TT would be associated with intestinal metaplasia, and that a positive Helicobacter pylori cagA serology could be a useful biomarker for the intervention and prevention of pre-cancerous lesions. Further studies are required in the Colombian population in order to evaluate the relationship found between IL1B-511 and intestinal metaplasia.

Características histológicas de la gastritis asociada a los genotipos cagA y vacA de Helicobacter pylori difieren en 2 zonas de riesgo opuesto para cáncer gástrico en Colombia / Gastritis associated with cagA and vacA genotypes of Helicobacter pylori: histological features differ in 2 areas of Colombia at risk for gastric cancer

Objetivo. Analizar los cambios histopatológicos en la mucosa gástrica de portadores de Helicobacter pylori, genotipos cagA y vacA, en 2 zonas de riesgo opuesto para cáncer gástrico en Colombia. Materiales y métodos. Se estudiaron 297 pacientes con gastritis asociadas a infección por Helicobacter pylori; 109 de la zona de riesgo alto y 107 de la zona de riesgo bajo para cáncer gástrico con toma de biopsias en antro y cuerpo gástrico; la clasificación y calificación de las gastritis se hizo según el sistema de estadificación OLGA y el sistema actualizado de Sydney. La genotipificación de Helicobacter pylori se realizó mediante PCR, a partir de extracción de ADN de biopsias. El análisis estadístico incluyó la prueba Mann-Whitney, X2, regresión lineal múltiple y regresión logística multivariada. Resultados. La severidad de las alteraciones histopatológicas en los pacientes infectados con los genotipos cagA y vacAs1/m1 fue mayor en la zona de riesgo alto (p <= 0,05). El grado de inflamación crónica, atrofia y metaplasia es mayor en los pacientes de la zona de riesgo alto. El gen vacA se asoció a una severidad mayor de atrofia y metaplasia. En gen cagA positivo aumenta el riesgo de metaplasia intestinal en la zona de riesgo alto (OR = 9,13; IC 95% 1,75-47,75). Conclusión. Los resultados sugieren que los cambios histopatológicos resultantes de la infección gástrica por los genotipos cagA+ y vacAs1/m1 de Helicobacter pylori muestran un grado de severidad significativamente mayor de los parámetros histopatológicos en zonas de riesgo alto en comparación con las de riesgo bajo de cáncer gástrico(AU)

Objetive. To analyze histopathological changes in the gastric mucosa of carriers of Helicobacter pylori cagA and vacA in 2 areas of Columbia at risk for gastric cancer. Materials y methods. 297 patients with gastritis associated with Helicobacter pylori infection were studied; 109 from a high risk area for gastric cancer and 107 from a low risk area. Biopsies were taken from the antrum and body of the stomach; the OLGA staging for gastritis and the updated Sydney system for classification of gastritis were used for their classification and grading. The Helicobacter pylori genotyping was carried out with PCR on the DNA obtained from the biopsies. Statistical analysis included the Mann-Whitney test, X2, multiple linear regression and multivariate logistic regression. Results. The histopathological changes were more severe in patients infected with cagA and vacA1/m1 in the high risk area (P <= 0.05). There was a higher degree of chronic inflammation, atrophy and metaplasia in the patients in the high risk area. The gene vacA was associated with more severe atrophy and metaplasia. There was an increased risk of intestinal metaplasia in patients positive for the gene cagA in the high risk area (OR = 9.13; CI95% 1.75-47.75). Conclusions. The results suggest that the histopathological changes resulting from gastric infection with the cagA+ and vacAs1/m1 genes of Helicobacter pyloriare significantly more severe in areas of high risk for gastric cancer than in areas of low risk(AU)

CagA EPIYA polymorphisms in Colombian Helicobacter pylori strains and their influence on disease-associated cellular responses.

AIM: To investigate the influence of the CagA diversity in Helicobacter pylori (H. pylori) strains from Colombia on the host cell biology. METHODS: Eighty-four H. pylori-cagA positive strains with different Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs patterns, isolated from patients with gastritis (n = 17), atrophic gastritis (n = 17), duodenal ulcer (n = 16), intestinal metaplasia (n = 16) and gastric cancer (n = 18), were included. To determine the integrity of the cag pathogenicity island (cagPAI) we evaluated the presence of cagA, cagT, cagE, and cag10 genes by polymerase chain reaction. AGS gastric epithelial cells were infected with each strain and assayed for translocation and tyrosine phosphorylation of CagA by western blot, secretion of interleukin-8 (IL-8) by enzyme-linked immuno sorbent assay after taking supernatants from cocultures and cell elongation induction. For cell elongation quantification, coculture photographs were taken and the proportion of "hummingbird" cells (> 15 µm) was determined. RESULTS: Overall 72% (60/84) of the strains were found to harbor a functional cagPAI. Levels of phosphorylated CagA were significantly higher for isolates from duodenal ulcer than the ones in strains from gastritis, atrophic gastritis, intestinal metaplasia and gastric cancer (49.1% ± 23.1% vs 21.1% ± 19.5%, P < 0.02; 49.1% ± 23.1% vs 26.2% ± 14.8%, P < 0.045; 49.1% ± 23.1% vs 21.5% ± 19.5%, P < 0.043 and 49.1% ± 23.1% vs 29.5% ± 27.1%, P < 0.047 respectively). We observed variable IL-8 expression levels ranging from 0 to 810 pg/mL and from 8.8 to 1442 pg/mL at 6 h and 30 h post-infection, respectively. cagPAI-defective strains did not induce detectable levels of IL-8 at 6 h post-infection. At 30 h post-infection all strains induced IL-8 expression in AGS cells, although cagPAI-defective strains induced significantly lower levels of IL-8 than strains with a functional cagPAI (57.1 ± 56.6 pg/mL vs 513.6 ± 338.6 pg/mL, P < 0.0001). We did not observe differences in the extent of cell elongation induction between strains with a functional or a defective cagPAI in 6 h cocultures. At 24 h post infection strains with functional cagPAI showed high diversity in the extent of hummingbird phenotype induction ranging from 7% to 34%. cagPAI defective strains induced significantly lower levels of elongation than strains with functional cagPAI with one or more than one EPIYA-C motif (15.1% ± 5.2% vs 18.9% ± 4.7%, P < 0.03; and 15.1% ± 5.2% vs 20.0% ± 5.1%, P < 0.003 respectively). No differences were observed in cellular elongation induction or IL-8 expression among H. pylori strains bearing one and more than one EPIYA-C motifs, neither at 6 h nor at 24 h of coculture. There were no associations between the levels of induction of cell elongation or IL-8 expression and number of EPIYA motifs or pathology. CONCLUSION: The present work describes a lack of association between H. pylori CagA protein EPIYA motifs variations from Colombian isolates and disease-associated cellular responses.