Sonia Roman

Epidemiología de las hepatitis virales en México

The main etiology of liver disease in Mexico is alcohol and viral hepatitis. The aim of the present study was to analyze the current epidemiology of viral hepatitis in Mexico. From 2000 to 2007 the Ministry of Health reported 192 588 cases of hepatitis, 79% HAV, 3.3% HBV, 6% HCV, and 12% without a specific etiologic factor. Due to high endemic areas for HBV infection in native Mexican population, limitations in the diagnostic sensitivity and specificity of the serological immunoassays used to date and presence of occult hepatitis B in the country, the real prevalence of HBV infection could be even higher than HCV in Mexico. Hepatitis E virus in cirrhotic patients and in porcine farms could at least partially explain the cases of hepatitis that are diagnosed without a specific etiologic agent. Specific strategies to establish control regulations against viral hepatitis infections in Mexico are proposed.

Occult hepatitis B in the genotype H-infected Nahuas and Huichol native Mexican population†

Mexico is considered to be a low endemic country for HBV infection. However, a high anti‐HBc against a low hepatitis B surface antigen (HBsAg) seroprevalence is the reported characteristic of native Mexicans. HBV diagnosis and genotype distribution was examined in native populations (Nahuas and Huichol, n = 306), and compared to a non‐native population (Mestizos, n = 17). Overall, 6% of the natives were positive for HBsAg and 33% had detectable anti‐HBc. HBsAg prevalence was lower in Nahuas compared to Huichols (1.4% vs. 9.4%, P < 0.002). Occult hepatitis B was detected in 14.2% (41/289) of natives, who either tested positive (5.88%, 17/289 HBsAg‐negative) or negative for anti‐HBc marker (8%, 24/289 HBsAg‐negative). Age‐adjusted anti‐HBc seroprevalence and HBsAg quantitation revealed a sub‐optimal sensitivity of conventional immunoassays. Nahuas had HBV/H and Huichol had HBV/A as the predominant genotypes followed by genotypes D, C, B, A, and D, G and H, respectively. A less variable HBV/H was characteristic in Mestizos, compared to a much variable HBV/H identified among the Nahuas. In conclusion, these findings indicate a high HBV endemicity among native Mexican groups where occult B infection is common. The different distribution of HBV genotypes among natives suggests multiple reservoirs of HBV from which these genotypes spread into the local communities. High anti‐HBc seroprevalence against a low HBsAg prevalence rate may be due to the limited sensitivity of the immunoassays for the detection of HBsAg that are available in Mexico and/or unknown immunogenetic characteristics of native Mexicans. J. Med. Virol. 82:1527–1536, 2010.

Heterogeneity of Apolipoprotein E Polymorphism in Different Mexican Populations

ABSTRACT Mexico has approximately 100 million inhabitants. Most of the urban Mexican population has been considered mestizo (Indian and Spanish descent), whereas the Indian population predominates in rural areas and small towns in the countryside. In this study we analyzed the apolipoprotein E (APOE) polymorphism in Guadalajara (the second largest metropolitan area of Mexico) and its surrounding areas, two adjoining states (Nayarit and Durango), and an Indian town (Huichol Indians) from western Mexico. APOE*3 was the most common allele, and APOE*3/*3 was the most common genotype in all populations studied. Guadalajara revealed the highest frequency of the APOE*2 allele (7.8%); the frequency decreased in the rural area (4.4%), followed by Nayarit (1.6%), and was absent in Durango and in the Huichols. On the contrary, the lowest frequency of the APOE*4 allele was in Guadalajara (8.4%); the frequency increased in the rural area (9.3%), in Nayarit and Durango (11.5% and 11.7%), and reached a high frequency in the Huichol Indians (28%). The distribution of the APOE allele in the western population of Mexico is similar to those described in Mexican American migrants living in the United States but is different from those populations living in Mexico City. This study shows the heterogeneity of the Mexican population, where the frequency of the APOE*2 allele is higher in Guadalajara than in other urban areas of Mexico and is similar to frequencies described in the Caucasian population. On the contrary, the Huichols revealed the highest frequency of the APOE*4 allele in Mexico and in the Americas. This information could be useful for the study of dyslipidemias associated with chronic diseases and as markers of ethnic variation in the Americas.

A systematic review and meta-analysis of Toxoplasma gondii infection among the Mexican population

BackgroundToxoplasmosis is a disease caused by Toxoplasma gondii and at least one-third of the world’s population has detectable T. gondii antibodies. The seroprevalence of T.gondii ranges from 15% to 50% among the Mexican general population. The aim of this work was to determine the mean prevalence and weighted mean prevalence of T. gondii infection, and to evaluate the epidemiological transition of infection in Mexico.MethodsPub Med, Lilacs, Medline, Latindex, Google Scholar data bases were searched to retrieve reports from 1951 up to 2012 regarding prevalence data, diagnostic tests and risk factors of infection among the adult population. Data collection and criteria eligibility was established in order to determine the crude prevalence (proportion of positive cases) of each study, together with weighted population prevalence according to individual research group categories to limit the bias that may impose the heterogeneous nature of the reports. A Forest Plot chart and linear regression analysis were performed by plotting the prevalence of infection reported from each study over a period of sixty years.ResultsA total of 132 studies were collected from 41 publications that included 70,123 individuals. The average mean prevalence was 27.97%, and weighted mean prevalence was 19.27%. Comparisons among different risk groups showed that the weighted prevalence was higher in women with miscarriages (36.03%), immunocompromised patients (28.54%), mentally-ill patients (38.52%) and other risk groups (35.13%). Toxoplasma infection among the Mexican population showed a downward trend of 0.1%/year over a period of sixty years that represents a 5.8% reduction in prevalence.ConclusionsThis analysis showed a downward trend of infection; however, there are individuals at high risk for infection such as immunocompromised patients, mentally-ill patients and pregnant women. Further research is required to provide better prevention strategies, effective diagnostic testing and medical management of patients. Educational efforts are required to avoid the transmission of infection in populations that cannot be controlled by drugs alone.

Hepatitis B virus infection in Latin America: A genomic medicine approach

Hepatitis B virus (HBV) infection is the leading cause of severe chronic liver disease. This article provides a critical view of the importance of genomic medicine for the study of HBV infection and its clinical outcomes in Latin America. Three levels of evolutionary adaptation may correlate with the clinical outcomes of HBV infection. Infections in Latin America are predominantly of genotype H in Mexico and genotype F in Central and South America; these strains have historically circulated among the indigenous population. Both genotypes appear to be linked to a benign course of disease among the native and mestizo Mexicans and native South Americans. In contrast, genotypes F, A and D are common in acute and chronic infections among mestizos with Caucasian ancestry. Hepatocellular carcinoma is rare in Mexicans, but it has been associated with genotype F1b among Argentineans. This observation illustrates the significance of ascertaining the genetic and environmental factors involved in the development of HBV-related liver disease in Latin America, which contrast with those reported in other regions of the world.

Characteristics of hepatitis B virus genotype G coinfected with genotype H in chimeric mice carrying human hepatocytes.

Accumulated evidence indicated that hepatitis B virus genotype G (HBV/G) is present exclusively in coinfection with other HBV genotypes. In Mexico, HBV/G from 6 men who had sex with men were coinfected with HBV/H. Phylogenetically complete genomes of the 6 Mexican HBV/G strains were closely related to previous ones from the US/Europe. Using uPA/SCID mice with human hepatocytes, monoinfection with HBV/G did not result in detectable HBV DNA in serum, whereas superinfection with HBV/G at week 10 inoculated HBV/H when HBV/H DNA was elevated to >10(7) copies/mL has enhanced the replication of HBV/G. The HBV/G was enhanced in another 3 inoculated with a serum passage containing HBV/G with a trace of HBV/H. Coinfection of mice with HBV/G and H induced fibrosis in the liver. In conclusion, the replication of HBV/G can be enhanced remarkably when it is coinfected with HBV/H. Coinfection with HBV/G may be directly cytopathic in immunosuppressive conditions.

Distribution of HBV genotypes F and H in Mexico and Central America.

The distribution of HBV genotypes is associated with populations of specific geographical regions of the world. We show data from the GenBank sequence database and medical reports, which indicate that HBV genotype H (HBV/H) is mainly distributed in Mexico, whereas HBV genotype F (HBV/F) is distributed in countries from Central America. The phylogenetic analysis and historical records suggest that HBV/H has been present in Mexico even before the arrival of the Spaniards. Interestingly, occult hepatitis B is a common finding in both natives and patients with chronic liver disease in Mexico. This suggests that an immunogenic background could be important during the natural history of liver diseases. The estimated large number of HBV/H-infected patients in Mexico does not correlate with the total number of patients with chronic liver disease and cirrhosis reported in the country. This may be because of the fact that HBV infection is often masked by alcoholic liver disease, HCV coinfection and/or obesity. Here, we analyse the data concerning the distribution of HBV/F and HBV/H genotypes in Central America and Mexico. Specifically, we focus on the effect of molecular epidemiology and pathogenesis of HBV/H. These recent findings reveal new areas of study with therapeutic potential in viral liver diseases.

Association of the ε2 Allele of Apoe Gene to Hypertriglyceridemia and to Early‐Onset Alcoholic Cirrhosis

BACKGROUND The diverse incidence of alcoholic cirrhosis around the world and the fact that not all alcoholic drinkers develop liver disease indicates that genetic and environmental factors play an important role in the development of liver cirrhosis. Lipids participate in early stages of alcoholic cirrhosis. Therefore variations in the plasma lipid profile due to primary (genetic) or secondary (environmental) dyslipidemia could affect the development of liver disease. The aim of this study was to analyze the lipid profile and apolipoprotein E (APOE) polymorphism in patients with alcoholic liver cirrhosis (AC) and determine the risk associated with genotype polymorphism with the onset of alcoholic cirrhosis. METHODS In a case and control study, 86 patients with AC divided into hyperlipidemic (H) and non-hyperlipidemic (non-H) groups, and 133 healthy individuals (C) matched by age and sex were studied. Lipid profile and liver function tests were measured by enzymatic methods. The APOE genotypes were identified by PCR-RFLPs. RESULTS A statistically significant increase of the APOE*2 allele and genotypes 2/2, 2/3, and 2/4 was present in AC patients compared to C group. A hyperlipidemic state characterized by increased levels of triglycerides and apolipoprotein B (APOB) and a decrease of high density lipoprotein-cholesterol (HDL-c) was detected in young-aged patients (31.2 +/- 6.2 years old vs. 46.3 +/- 12.5 years old). In this group, hypertriglyceridemia was closely associated to APOE*2 allele and to an early onset of liver cirrhosis. By contrast, APOE*4 allele was associated with a longer duration of alcohol intake (>20 years) in the non-H group. CONCLUSIONS This study shows the association of hypertriglyceridemia and APOE allele with the early onset of alcoholic liver cirrhosis, and the interaction between environmental factors, such as duration of alcohol abuse and amount of alcohol intake, and genetic factors (APOE*2 allele) on the hypertriglyceridemic process.

HBV endemicity in Mexico is associated with HBV genotypes H and G.

Hepatitis B virus (HBV) genotypes have distinct genetic and geographic diversity and may be associated with specific clinical characteristics, progression, severity of disease and antiviral response. Herein, we provide an updated overview of the endemicity of HBV genotypes H and G in Mexico. HBV genotype H is predominant among the Mexican population, but not in Central America. Its geographic distribution is related to a typical endemicity among the Mexicans which is characterized by a low hepatitis B surface antigen seroprevalence, apparently due to a rapid resolution of the infection, low viral loads and a high prevalence of occult B infection. During chronic infections, genotype H is detected in mixtures with other HBV genotypes and associated with other co-morbidities, such as obesity, alcoholism and co-infection with hepatitis C virus or human immunodeficiency virus. Hepatocellular carcinoma prevalence is low. Thus, antiviral therapy may differ significantly from the standard guidelines established worldwide. The high prevalence of HBV genotype G in the Americas, especially among the Mexican population, raises new questions regarding its geographic origin that will require further investigation.

Sweet Taste Receptor TAS1R2 Polymorphism (Val191Val) Is Associated with a Higher Carbohydrate Intake and Hypertriglyceridemia among the Population of West Mexico.

Some high-carbohydrate diets may lead to obesity and multiple metabolic disorders, including hypertriglyceridemia (HTG). This lipid abnormality is considered an important risk factor for cardiovascular disease and type 2 diabetes. The sweet taste receptor TAS1R2 polymorphism (Ile191Val) has been reported to be associated with carbohydrate intake. The aim of this study was to analyze the association of the TAS1R2 gene polymorphism with carbohydrate intake and HTG among the population of West Mexico. In a cross-sectional study, 441 unrelated subjects were analyzed for TAS1R2 genotypes (Ile/Ile, Ile/Val and Val/Val) by an allelic discrimination assay. Biochemical tests and a three-day food record were assessed. The Val/Val genotype carriers had a higher intake of total carbohydrates, fiber and servings of cereals and vegetables than the other genotype carriers. The Val/Val genotype conferred a higher risk for HTG than the Ile/Val and Ile/Ile genotypes (OR = 3.26, 95%CI 1.35–7.86, p = 0.006 and OR = 2.61, 95%CI 1.12–6.07, p = 0.02, respectively). Furthermore, the Val/Val genotype was associated with approximately 30% higher triglycerides compared with Ile/Val and Ile/Ile genotypes (β = 44.09, 95%CI 9.94–78.25, p = 0.01 and β = 45.7, 95%CI 10.85–80.54, p = 0.01, respectively). In conclusion, the Val/Val genotype of TAS1R2 was associated with a higher carbohydrate intake and HTG.