Verónica Vallejo-Ruiz

Prevalence of hepatitis C virus in the Mexican population: A systematic review

BACKGROUND Although hepatitis C virus (HCV) infection is considered a relevant public health problem in Mexico, the prevalence is still under discussion. The objective of this study was to conduct a systematic review to explore the prevalence of HCV infection in the Mexican population. METHODS A systematic review of studies reporting prevalence in Mexican population was performed using several free-access databases. RESULTS Sixty-eight works fulfilled the search criteria. From these, 44 studies involved asymptomatic subjects and 28 involved patients or high-risk subjects. Prevalence of blood donors (6,955,558 persons) ranged from 0.0% to 2.05%, with 7/32 studies reporting values >1%, whereas prevalence of non-donor asymptomatic subjects (28,528 persons) from 0.0% to 2.7%, with 7/11 studies reporting values >1%, and medical personnel from 0.0% to 2.08% (1,227 persons), with 4/11 studies reporting values >1%. Prevalence of patients with chronic hepatic disease ranged from 6.7% to 77%. The most prevalent genotype was 1 (30.0-87.5%), of which subtype 1b is the most frequent (11.9-61.9%). The main risk factors were blood transfusion and unprotected sex or having multiple sex partners. CONCLUSIONS The prevalence in the Mexican population seems to be in accordance with that previously estimated by the World Health Organization (1-2.5%).

Hepatitis C virus infection in blood donors from the state of Puebla, Mexico

BackgroundWorldwide, 130 million persons are estimated to be infected with HCV. Puebla is the Mexican state with the highest mortality due to hepatic cirrhosis. Therefore, it is imperative to obtain epidemiological data on HCV infection in asymptomatic people of this region. The objective of present study was to analyze the prevalence of antibodies and genotypes of hepatitis C virus (HCV) in blood donors from Puebla, Mexico.ResultsThe overall prevalence was 0.84% (515/61553). Distribution by region was: North, 0.86% (54/6270); Southeast, 1.04% (75/7197); Southwest, 0.93% (36/3852); and Central, 0.79% (350/44234). Ninety-six donors were enrolled for detection and genotyping of virus, from which 37 (38.5%) were HCV-RNA positive. Detected subtypes were: 1a (40.5%), 1b (27.0%), mixed 1a/1b (18.9%), undetermined genotype 1 (5.4%), 2a (2.7%), 2b (2.7%), and mixed 1a/2a (2.7%). All recovered donors with S/CO > 39 were HCV-RNA positive (11/11) and presented elevated ALT; in donors with S/CO < 39 HCV-RNA, positivity was of 30.4%; and 70% had normal values of ALT. The main risk factors associated with HCV infection were blood transfusion and surgery.ConclusionsHCV prevalence of donors in Puebla is similar to other Mexican states. The most prevalent genotype is 1, of which subtype 1a is the most frequent.

Increased expression of sialic acid in cervical biopsies with squamous intraepithelial lesions

BackgroundAltered sialylation has been observed during oncogenic transformation. Sialylated oligosaccharides of glycoproteins and glycolipids have been implicated in tumor progression and metastases. In the cervical cancer high levels of sialic acid have been reported in the patients serum, and an increased of total sialic acid concentration has been reported for the cervical neoplasia and cervical cancer. This study investigates the changes in expression and distribution of α2,3-linked sialic acid and α2,6- linked sialic acid in low and high squamous intraepithelial lesions and in normal tissue.MethodsLectin histochemistry was used to examine the expression and distribution of sialic acid in different grades of cervical neoplasia. We applied Maackia amurensis lectin, which interacts with α2,3-linked sialic acid and Sambucus nigra lectin specific for α2,6-linked sialic acid.ResultsThe histochemical analysis showed that α2,3-linked sialic acid and α2,6- linked sialic acid increased in intensity and distribution in concordance with the grade of squamous intraepithelial lesion (SIL). These results are in concordance with a previous study that reports increased RNAm levels of three sialyltransferases.ConclusionsThese results show that the change in sialylation occurs before cancer development and may play an important role in cellular transformation. These findings provide the basis for more detailed studies of the possible role of cell surface glycoconjugates bearing sialic acid in the cellular cervix transformation.

Interferon lambda inhibits dengue virus replication in epithelial cells.

BackgroundIn viral disease, infection is controlled at the cellular level by type I interferon (IFN-I), but dengue virus (DENV) has the ability to inhibit this response. Type III interferon, also known as lambda IFN (IFN-III or IFN-λ), is a complementary pathway to the antiviral response by IFN-I. This work analyzed the IFN-λ (IFN-III) mediated antiviral response against DENV serotype 2 (DENV-2) infection.MethodsDengue fever patients were sampled to determine their IFN-λ levels by ELISA. To study the IFN-λ response during DENV infection we selected the epithelial cell line C33-A, and we demonstrated that it is permissive to DENV-2 infection. The effect of IFN-λ on virus replication was determined in these cells, in parallel to the expression of IFN-stimulated genes (ISGs), and Suppressor of Cytokine Signaling (SOCS), genes measured by RT-qPCR.ResultsWe found increased (~1.8 times) serological IFN-λ in dengue fever patients compared to healthy blood donors. IFN-λ inhibited DENV-2 replication in a dose-dependent manner in vitro. The reduction of viral titer corresponded with increased ISG mRNA levels (MX1 and OAS1), with the highest inhibition occurring at ISG’s peak expression. Presence of IFN-negative regulators, SOCS1 and SOCS3, during DENV-2 infection was associated with reduced IFN-λ1 expression.ConclusionsEvidence described here suggests that IFN-λ is a good candidate inhibitor of viral replication in dengue infection. Mechanisms for the cellular and organismal interplay between DENV and IFN- λ need to be further studied as they could provide insights into strategies to treat this disease. Furthermore, we report a novel epithelial model to study dengue infection in vitro.

Prevalence of human papillomavirus genotypes in women from a rural region of Puebla, Mexico

OBJECTIVE To determine the prevalence of human papillomavirus (HPV) genotypes 6, 11, 16, 18, and 31 in Mexican women living in rural areas of Puebla, Mexico and to evaluate risk factors associated with cervical neoplasm in this population. METHODS A cross-sectional study was conducted in 326 women at the General Hospital of Metepec, Puebla. Cervical samples were obtained using a cytobrush and tested for HPV genotypes by PCR assays using type-specific primers. A questionnaire was completed regarding gynecological, obstetric, and sexual behavior of the patients. RESULTS The overall prevalence of HPV infection was 25.4%, with two peaks of higher HPV prevalence in those aged 18-24 and 55-64 years. The individual genotype prevalences were: 9.6% HPV6, 4.8% HPV11, 54.2% HPV16, 37.3% HPV18, and 9.6% HPV31. Number of pregnancies was the most important risk factor associated with cervical cancer. CONCLUSIONS HPV16 was the most common type found in all cervical lesions. Genotype 16 or 18 was detected in patients with a diagnosis of cervical cancer. We found two peaks of age-specific HPV prevalence similar to findings reported worldwide.

Female breast cancer incidence and mortality in Mexico, 2000-2010.

The objective of this study was to investigate the recent incidence and mortality trends for breast cancer in Mexican females. Data between 2000 and 2010 from the Department of Epidemiology of the Ministry of Health, and International Agency for Research on Cancer (IARC) were analyzed. Age-standardized rates (ASRs) and annual percent changes (APCs) were calculated. The absolute incidence and mortality rates of breast cancer increased: 3,726 and 4,615 in 2000 to 8,545 and 4,966 in 2010, respectively. Incidence increased over time in all age groups tested, the 60-64 age group had the highest ASR (57.4 per 100,000 women in 2010), while the 20-44 age group had the lowest ASR (12.3 in 2010). The results show that incidence of breast cancer has increased in Mexico during last one decade, especially among older women, while the downturn observed in mortality mainly reflects improved survival as a result of earlier diagnosis and better cancer treatment.

Structure-function analysis of two variants of mumps virus hemagglutinin-neuraminidase protein

A point mutation from guanine (G) to adenine (A) at nucleotide position 1081 in the hemagglutinin-neuraminidase (HN) gene has been associated with neurovirulence of Urabe AM9 mumps virus vaccine. This mutation corresponds to a glutamic acid (E) to lysine (K) change at position 335 in the HN glycoprotein. We have experimentally demonstrated that two variants of Urabe AM9 strain (HN-A1081 and HN-G1081) differ in neurotropism, sialic acidbinding affinity and neuraminidase activity. In the present study, we performed a structure-function analysis of that amino acid substitution; the structures of HN protein of both Urabe AM9 strain variants were predicted. Based on our analysis, the E/K mutation changes the protein surface properties and to a lesser extent their conformations, which in turn reflects in activity changes. Our modeling results suggest that this E/K interchange does not affect the structure of the sialic acid binding motif; however, the electrostatic surface differs drastically due to an exposed short alpha helix. Consequently, this mutation may affect the accessibility of HN to substrates and membrane receptors of the host cells. Our findings appear to explain the observed differences in neurotropism of these vaccine strains.

Human papillomavirus genotypes among females in Mexico: a study from the Mexican institute for social security.

BACKGROUND The aetiological relationship between human papillomavirus (HPV) infection and cervical cancer (CC) is widely accepted. Our goal was to determine the prevalence of HPV types in Mexican women attending at the Mexican Institute for Social Security from different areas of Mexico. MATERIALS AND METHODS DNAs from 2,956 cervical samples were subjected to HPV genotyping: 1,020 samples with normal cytology, 931 with low-grade squamous intraepithelial lesions (LGSIL), 481 with high grade HGSIL and 524 CC. RESULTS Overall HPV prevalence was 67.1%. A total of 40 HPV types were found; HPV16 was detected in 39.4% of the HPV-positive samples followed by HPV18 at 7.5%, HPV31 at 7.1%, HPV59 at 4.9%, and HPV58 at 3.2%. HPV16 presented the highest prevalence both in women with altered or normal cytology and HPV 18 presented a minor prevalence as reported worldwide. The prevalence ratio (PR) was calculated for the HPV types. The analysis of PR showed that HPV16 presents the highest association with CC, HPV 31, -33, -45, -52 and -58 also demonstrating a high association. CONCLUSIONS The most prevalent HPV types in cervical cancer samples were -16, -18, -31, but it is important to note that we obtained a minor prevalence of HPV18 as reported worldwide, and that HPV58 and -52 also were genotypes with an important prevalence in CC samples. Determination of HPV genotypes is very important in order to evaluate the impact of vaccine introduction and future cervical cancer prevention strategies.

Quantitative analysis of the suppressors of cytokine signaling 1 and 3 in peripheral blood leukocytes of patients with multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease characterized by a triad of inflammation, demyelination and gliosis. Because the suppressors of cytokine signaling (Socs) regulate the immune response, we quantified SOCS1 and SOCS3 transcription in peripheral blood leukocytes of patients with MS. SOCS1 transcription decreased significantly in MS patients compared with neurologically healthy persons (0.08±0.02 vs. 1.02±0.23; p=0.0001); while SOCS3 transcription increased in MS patients compared with controls (2.76±0.66 vs. 1.03±0.27; p=0.0008). Our results showed an imbalance of SOCS1 and SOCS3 transcription in MS patients, and a moderated negative correlation between them (Spearmans r=-0.57; p=0.0003).

Human papillomavirus genotyping by Linear Array and Next-Generation Sequencing in cervical samples from Western Mexico

BackgroundThe Linear Array® (LA) genotyping test is one of the most used methodologies for Human papillomavirus (HPV) genotyping, in that it is able to detect 37 HPV genotypes and co-infections in the same sample. However, the assay is limited to a restricted number of HPV, and sequence variations in the detection region of the HPV probes could give false negatives results. Recently, 454 Next-Generation sequencing (NGS) technology has been efficiently used also for HPV genotyping; this methodology is based on massive sequencing of HPV fragments and is expected to be highly specific and sensitive. In this work, we studied HPV prevalence in cervixes of women in Western Mexico by LA and confirmed the genotypes found by NGS.MethodsTwo hundred thirty three cervical samples from women Without cervical lesions (WCL, n = 48), with Cervical intraepithelial neoplasia grade 1 (CIN I, n = 98), or with Cervical cancer (CC, n = 87) were recruited, DNA was extracted, and HPV positivity was determined by PCR amplification using PGMY09/11 primers. All HPV- positive samples were genotyped individually by LA. Additionally, pools of amplicons from the PGMY-PCR products were sequenced using 454 NGS technology. Results obtained by NGS were compared with those of LA for each group of samples.ResultsWe identified 35 HPV genotypes, among which 30 were identified by both technologies; in addition, the HPV genotypes 32, 44, 74, 102 and 114 were detected by NGS. These latter genotypes, to our knowledge, have not been previously reported in Mexican population. Furthermore, we found that LA did not detect, in some diagnosis groups, certain HPV genotypes included in the test, such as 6, 11, 16, 26, 35, 51, 58, 68, 73, and 89, which indicates possible variations at the species level.ConclusionsThere are HPV genotypes in Mexican population that cannot be detected by LA, which is, at present, the most complete commercial genotyping test. More studies are necessary to determine the impact of HPV-44, 74, 102 and 114 on the risk of developing CC. A greater number of samples must be analyzed by NGS for the most accurate determination of Mexican HPV variants.