Biomedical subjects

Luisa Lina Villa

Publications and source records attributed to Luisa Lina Villa.

16 recordsLinked to original sources

PubMed2007

High grade cervical lesions are caused preferentially by non-European variants of HPVs 16 and 18.

The intratypic variability of HPVs 16 and 18 has been extensively studied and has been used as an important tool in epidemiological studies of viral transmission, persistence and progression to clinically relevant cervical lesions. Infections by non-European variants of HPVs 16 and 18 are associated with an increased risk for the development of high grade squamous intraepithelial lesions (HSIL). Our aim was to correlate the intratypic molecular variability of both HPV types and risk of persistent infection and lesion outcome in a cohort study conducted in Brazil. We characterized molecular variants of HPV types 16 and 18 by sequencing a fragment of the LCR, and of the E6 and L1 genes, for HPV-16 variants only. For both types, European variants composed the most prevalent and diverse group. Persistent infections with HPV-18 were associated with continuous detection of European variants. However, risk for simultaneous detection of HSIL and HPV DNA was higher in women harboring non-European variants of HPV-16. The same trend was observed with HSIL detected during follow-up. Our study confirms the association between non-European variants and risk of cervical neoplasia, and highlights the importance of their geographic distribution for cervical cancer risk assessment.

Adolescent↗

PubMed2006

Human papillomavirus type 16 molecular variants in Guarani Indian women from Misiones, Argentina.

OBJECTIVE: To identify human papillomavirus type 16 (HPV16) E6 and L1 molecular variants infecting Guarani Indian women settled in Misiones, Argentina, a region with a high prevalence of cervical cancer. Some intratypic molecular variants of HPV16 have been associated with greater oncogenic risk, but their implication in the etiology of cervical cancer is still uncertain. METHODS: Seventy HPV16 positive cervical samples from Guarani Indian women settled in two different areas of Misiones, Argentina, (34 from the northern area and 36 from the central area), were analyzed. Thirty-seven had normal cytology, 18 had a low-grade squamous intraepithelial lesion (LGSIL), and 15 a high-grade squamous intraepithelial lesion (HGSIL). HPV16 E6 and L1 molecular variants were identified by PCR, followed by dot blot hybridization with 23 and 12 biotinylated oligonucleotide probes, respectively. RESULTS: The frequency of HPV16 variants over the Guarani population was 51% EP (European prototype), 32% E-350G, 9% Af1-a (African 1), 4% E-6862C, 3% Af2-a, and 1% AA-a (Asian-American). The distribution of variants was not homogeneous in the two areas under analysis, with the northern area being more diverse showing 74% of European variants, while the central area presented exclusively E variants. No statistically significant association was found between any particular variant and grade of cervical lesion. CONCLUSION: This study reports for the first time HPV16 E6 and L1 molecular variants infecting women from an aboriginal community inhabiting a rainforest region of South America. The presence of E class variants could be attributed primarily to contacts with the Spanish conquerors, and Af variants from African slaves introduced later in the South American continent.

Adolescent↗

PubMed2006

Vaccines against rotavirus and human papillomavirus (HPV).

OBJECTIVE: To briefly review strategies aimed at the development of rotavirus and HPV vaccines, with emphasis on the current status of studies assessing the safety, reactogenicity, immunogenicity and efficacy of recently developed vaccines. SOURCES OF DATA: This review focuses on articles published from 1996 to 2006, mainly those from the last five years, with special emphasis on data obtained from recently completed studies involving a new live attenuated human rotavirus vaccine and a virus-like particle (HPV) vaccine. SUMMARY OF THE FINDINGS: Strategies for developing rotavirus vaccines ranged from Jennerian approaches to the new human-derived rotavirus vaccine. Currently, two rotavirus vaccines are recognized as both efficacious and safe: a pentavalent human-bovine reassortant vaccine and a vaccine derived from an attenuated rotavirus of human origin. The second of these has been evaluated in more than 70,000 infants all over the world. Prophylactic vaccines against HPV have been tested in more than 25,000 young individuals around the world. Results from phase II and III clinical studies indicate that such vaccines against the most common types of HPV, those linked to both genital warts and 70% of cervical cancers, are safe and highly efficacious. CONCLUSIONS: A future rotavirus immunization program covering 60 to 80% of infants worldwide is likely to reduce by at least 50% the number of rotavirus-associated hospitalizations and deaths. It is also reasonable to expect that implementation of HPV prophylactic vaccines will reduce the burden of the HPV-related diseases that presently impact millions of people around the world.

Animals↗

PubMed2006

Chapter 3: HPV type-distribution in women with and without cervical neoplastic diseases.

Geographical widespread data on human papillomavirus (HPV) type-distribution are essential for estimating the impact of HPV-16/18 vaccines on cervical cancer and cervical screening programmes. Epidemiological studies employing a variety of HPV typing protocols have been collated in meta-analyses. HPV-16/18 is estimated to account for 70% of all cervical cancers worldwide, although the estimated HPV-16/18 fraction is slightly higher in more developed (72-77%) than in less developed (65-72%) regions. About 41-67% of high-grade squamous intraepithelial lesion (HSIL), 16-32% of low-grade squamous intraepithelial lesion (LSIL) and 6-27% of atypical squamous cells of undetermined significance (ASCUS) are also estimated to be HPV-16/18-positive, thus highlighting the increasing relative frequency of HPV-16/18 with increasing lesion severity. After HPV-16/18, the six most common HPV types are the same in all world regions, namely 31, 33, 35, 45, 52 and 58; these account for an additional 20% of cervical cancers worldwide.

Female↗

PubMed2006

Prophylactic HPV vaccines: reducing the burden of HPV-related diseases.

HPV-associated diseases, such as cervical and other anogenital cancers, cervical and anal intraepithelial neoplasia, genital warts, and recurrent respiratory papillomatosis confer considerable morbidity and mortality, and are significant health care concerns. Successful vaccination strategies that protect against HPV infection are expected to substantially reduce HPV-related disease burden. Prophylactic HPV vaccines in late stages of clinical testing are composed of HPV L1 capsid protein that self-assemble into virus-like particles (VLPs) when expressed in recombinant systems. Proof-of-principle trials have suggested that intramuscular injections of VLPs results in strong adaptive immune responses, both B- and T-cell mediated, that are capable of neutralizing subsequent natural infections. Furthermore, phase 2 trials of a bivalent vaccine designed to protect against high-risk HPV types 16 and 18 and a quadrivalent vaccine designed to protect against HPV 16 and 18, and low-risk, genital wart-causing HPV 6 and 11 have demonstrated that VLP vaccines reduce the incidence of HPV-associated disease in vaccinated individuals. To derive the greatest public health benefit, HPV vaccines offering protection from cervical cancer and genital warts will, ideally, be administered prior to the initiation of sexual activity; therefore, educational initiatives will be essential to communicate the risks and adverse consequences of HPV infection and to foster widespread vaccine acceptance.

Capsid Proteins↗

PubMed2006

The prevalence of human papillomavirus in the oropharynx in healthy individuals in a Brazilian population.

Oncogenic human papillomavirus (HPV), a causative agent of uterine cervical cancer, has also been detected in head and neck squamous cell cancers, especially in squamous cell carcinomas of the tonsils. However, the true HPV prevalence in normal and neoplasic oropharyngeal mucosa remains uncertain. To determine the prevalence of HPV DNA in normal oropharyngeal mucosa of cancer-free individuals, a study was carried out on 50 Brazilian subjects. PCR was performed to identify HPV DNA in samples from four sites in the oropharynx (tonsils, soft palate, base of the tongue, and back wall of the pharynx). For amplification of the HPV DNA, MY09/11 consensus primers were used, and specific genotypes were identified by dot-blot hybridization or cloning and sequencing. HPV DNA was present in 14.0% of the individuals, and the identified genotypes were 16, 18, 52, and 61. All these types are considered high-risk (HR) HPV. The tonsils and the soft palate were the sites with the highest HPV prevalence. This study shows the prevalence of HR HPV in the oropharynx of normal individuals. However, the prevalence of HPV is still unclear, and if HPV infection in a healthy it is not known individual predisposes to HPV-associated disease such as oropharyngeal cancer. Thus, it is important to assess the prevalence of HPV in cancer-free individuals, in order to compare it with the HPV prevalence in oropharyngeal carcinomas and to attempt to determine the true role of HPV in the development of head and neck squamous cell cancers.

Adolescent↗

PubMed2006

Production of human papillomavirus type 16 L1 virus-like particles by recombinant Lactobacillus casei cells.

Infections with human papillomavirus type 16 (HPV-16) are closely associated with the development of human cervical carcinoma, which is one of the most common causes of cancer death in women worldwide. At present, the most promising vaccine against HPV-16 infection is based on the L1 major capsid protein, which self-assembles in virus-like particles (VLPs). In this work, we used a lactose-inducible system based on the Lactobacillus casei lactose operon promoter (plac) for expression of the HPV-16 L1 protein in L. casei. Expression was confirmed by Western blotting, and an electron microscopy analysis of L. casei expressing L1 showed that the protein was able to self-assemble into VLPs intracellularly. The presence of conformational epitopes on the L. casei-produced VLPs was confirmed by immunofluorescence using the anti-HPV-16 VLP conformational antibody H16.V5. Moreover, sera from mice that were subcutaneously immunized with L. casei expressing L1 reacted with Spodoptera frugiperda-produced HPV-16 L1 VLPs, as determined by an enzyme-linked immunosorbent assay. The production of L1 VLPs by Lactobacillus opens the possibility for development of new live mucosal prophylactic vaccines.

Animals↗

PubMed2006

Higher expression and activity of metalloproteinases in human cervical carcinoma cell lines is associated with HPV presence.

Matrix metalloproteinases (MMPs) MMP-2, MMP-9, and MT1-MMP are required for basement membrane degradation in cervical carcinoma. We evaluated the expression and activity of MMPs and their inhibitors RECK and TIMP-2 in 3 human invasive cervical carcinoma cell lines. Two HPV16-positive cell lines (SiHa and CaSki) and an HPV-negative cell line (C33A) were cultured either onto a type-I collagen gel, Matrigel, or plastic, to recreate their three-dimensional growth environment and evaluate the expression of these genes using quantitative real-time PCR. We also analyzed the gelatinolytic activity of MMP-2 and MMP-9 by zymography. We found that HPV (human papillomavirus)-positive cell lines express higher levels of MMP-2, MT1-MMP, and TIMP-2 than the HPV negative cell line. In addition, MMP-9 was expressed at very low levels in both HPV-negative and HPV-positive cell lines. We also observed that the expression of the RECK gene is higher in CaSki cells, being associated with higher pro-MMP-2 activity. Furthermore, Matrigel substrate influences MMP-2 expression in both SiHa and CaSki cells. On the other hand, we found that type-I collagen gel, but not Matrigel, can enhance pro-MMP-2 activity in all cell lines. Our results suggest that the presence of HPV is related to increased expression of MMP-2, MT1-MMP, and TIMP-2, and that pro-MMP-2 activity is higher in HPV-positive than in HPV-negative cells.

Carcinoma↗

PubMed2005

Different P105 promoter activities among natural variants of human papillomavirus type 18.

Association between non-European variants of human papillomavirus (HPV) type 16 (HPV-16) and HPV-18 and cervical lesions has been suggested. To compare the P105 promoter activity among 6 HPV-18 variants, their complete long control regions (LCRs), as well as that of HeLa cells, were cloned upstream of the luciferase gene and transiently transfected in C33 cells. Whereas the B18-2 European variant showed the lowest promoter activity, the Asian-Amerindian variant, B18-3, had the highest activity. All variants tested were more active than the P97 HPV-16 prototype promoter. Differences in the LCR that impact P105 promoter activity could be responsible for the observed variability in oncogenic potential.

Base Sequence↗

PubMed2003

Human papillomavirus type-16 variants in Quechua aboriginals from Argentina.

Cervical carcinoma is the leading cause of cancer death in Quechua indians from Jujuy (northwestern Argentina). To determine the prevalence of HPV-16 variants, 106 HPV-16 positive cervical samples were studied, including 33 low-grade squamous intraepithelial lesions (LSIL), 28 high-grade squamous intraepithelial lesions (HSIL), 9 invasive cervical cancer (ICC), and 36 samples from women with normal colposcopy and cytology. HPV genome variability was examined in the L1 and E6 genes by PCR-hybridization. In a subset of 20 samples, a LCR fragment was also analyzed by PCR-sequencing. Most variants belonged to the European branch with subtle differences that depended on the viral gene fragment studied. Only about 10% of the specimens had non-European variants, including eight Asian-American, two Asian, and one North-American-1. E6 gene analysis revealed that 43% of the samples were identical to HPV-16 prototype, while 57% corresponded to variants. Interestingly, the majority (87%) of normal smears had HPV-16 prototype, whereas variants were detected mainly in SIL and ICC. LCR sequencing yielded 80% of variants, including 69% of European, 19% Asian-American, and 12% Asian. We identified a new variant, the Argentine Quechua-51 (AQ-51), similar to B-14 plus two additional changes: G7842-->A and A7837-->C; phylogenetic inference allocated it in the Asian-American branch. The high proportion of European variants may reflect Spanish colonial influence on these native Inca descendants. The predominance of HPV-16 variants in pathologic samples when compared to normal controls could have implications for the natural history of cervical lesions.

Argentina↗

PubMed2003

Genetic susceptibility to infection with human papillomavirus and development of cervical cancer in women in Brazil.

Human papillomavirus (HPV) is considered to be a necessary but not sufficient cause for cervical cancer and, therefore, other factors contribute to the carcinogenic process. A hereditary component for this neoplasia has been reported and several studies indicate that genetic background of the host is important for cervical cancer susceptibility. Among genetic factors that could participate in the susceptibility to this tumor and disease outcome, polymorphic genes of the major histocompatibility complex (MHC), as well as a particular polymorphism in the p53 gene have been intensely investigated. From our analysis of 613 samples in Brazil, we found evidence to indicate that different polymorphic human leukocyte antigen (HLA) genes are involved in the clearance and maintenance of HPV infection. In addition, the homozygous codon 72 p53-Arg gene allele is associated with susceptibility to HPV-associated cervical carcinogenesis. However, supportive and opposing data have been reported in different populations. Therefore, international collaborative studies need to be conducted to define the consistency of the associations described.

Brazil↗

PubMed2003

Chapter 12: Human papillomavirus technologies.

Currently, human papillomavirus (HPV) DNA tests validated in large trials and epidemiological studies are the hybrid capture second-generation (HC2) HPV DNA assay and a variety of polymerase chain reaction (PCR) protocols employing degenerate or consensus primers. This article describes the currently available technology for HPV detection and discusses novel technologies and their potential for large-scale screening. Ideally, an HPV test should allow detection of multiple HPV types, identify individual types, and provide quantitative information about the viral load of each individual type found. Moreover, it should be easy to perform, be highly reproducible, with a high specificity and sensitivity, and amenable for high throughput analysis and automation. Because we do not yet fully understand the true value of viral load and the biological relevance of the different HPV types, any HPV test should be able to detect the clinically relevant high-risk types with a sufficient sensitivity of at least 10 000 genome copies per sample. To validate the different current and future test systems and to compare inter-laboratory performance we urgently need reference samples, validated reagents, and standardized protocols.

Biotechnology↗

PubMed2003

Vaccines against papillomavirus infections and disease.

Squamous cell carcinoma of the uterine cervix is the second cause of cancer-related deaths in women, the higher incidence being observed in developing countries. Infection with oncogenic types of human papillomavirus (HPV) is considered the major risk factor for the development of malignancies in the uterine cervix. However, HPV is considered to be a necessary but not sufficient cause for cervical cancer and, therefore, other factors contribute to the carcinogenic process, both present in the environment and from the host. Studies performed in animals, and more recently in humans, indicate that vaccination against the capsid proteins of the virus can prevent efficiently from infection. Furthermore, therapeutic vaccines are under investigation aiming the regression of papillomavirus induced tumors. The scientific basis for the development of papillomavirus vaccines and present status of clinical trials will be addressed in this chapter. This paper is available too at: http://www.insp.mx/salud/index.html.

Animals↗

PubMed2002

Past, present, and future of HPV research: highlights from the 19th International Papillomavirus Conference-HPV2001.

This manuscript summarizes the papers presented at the 19th International Papillomavirus Conference, held in Florianopolis, Brazil, September 1-7, 2001, divided in four main areas: Clinical diagnosis and screening, Epidemiology, Biology and Immunology. It provides an overview of what we know about the biology and life cycle of these viruses, their interaction with human and animal hosts, and the diseases that they cause. Highlights derive from the analysis of more than 500 papers presented at the Conference.

Animals↗

PubMed2002

[Genital human papillomavirus infection identification by molecular biology among asymptomatic women].

OBJECTIVE: To evaluate whether epidemiological factors may be associated to genital human papillomavirus (HPV) infection. METHODS: A cross-sectional study was carried out among 975 women seen at a public health service for cervical cancer screening in Porto Alegre, Brazil. Women were considered infected if tested positive to HPV either by Polymerase Chain Reaction (PCR) or Hybrid Capture II (HC-II) methods. Women with genital HPV infection were compared to women without infection drawn from the same population. RESULTS: The study enrolled 975 women. The HPV prevalence (both methods combined) in this population was 27%. However, when each diagnostic method is analyzed separately, HPV prevalence was 15% and 16% for HC-II and PCR, respectively. Unconditional multiple logistic regression was used to correlate disease status to women characteristics. A positive association was found with HPV infection for the following variables: years of schooling (11 years: OR=2.05; 95%CI =1.31; 3.20), married (OR=1.69; 95%CI=0.78; 2.00), number of lifetime sexual partners (2 partners: OR=1.67; 95%CI=1.01; 2.77; 4 or +: OR=2.18; 95%CI=1.15; 4.13), age at first intercourse (15-16 years: OR=4.05; 95%CI=0.89; 18.29). CONCLUSIONS: Various factors may contribute to genital HPV infection, especially those related to sexual behavior (young age at first intercourse, high number of lifetime sexual partners, and marital status), and those related to social and economic status (years of schooling).

Adolescent↗

PubMed2002

p53 as a new prognostic factor for lymph node metastasis in penile carcinoma: analysis of 82 patients treated with amputation and bilateral lymphadenectomy.

PURPOSE: Gold standard treatment for invasive penile carcinoma remains amputation and lymphadenectomy. This procedure has high morbidity and new prognostic factors on the incidence of metastasis would help select candidates to lymphadenectomy. Mutations in the p53 gene common in several neoplasms can be related to the prognosis. We studied 82 patients with penile carcinoma staged according to the 1978 TNM system who underwent amputation and bilateral lymphadenectomy to evaluate the prognostic value of immunohistochemical p53 staining in the primary tumor. MATERIALS AND METHODS: Immunoreactivity of p53 was studied with other clinicopathological variables, including patient age, stage, histological grade, tumor thickness, lymphatic and venous embolization, corpora cavernosa, corpus spongiosum and urethral infiltration, and human papillomavirus (HPV) status. We also determined its association with lymph node metastasis, the survival rate and the risk of death. In addition, we studied the association of p53 and HPV DNA with prognosis. All slides were reviewed by 1 pathologist. HPV DNA was detected by polymerase chain reaction using GP5/6+ generic primers. p53 expression was measured by immunohistochemical testing with monoclonal Clone DO-7 mouse anti-human p53 protein antibody (Dako A/S, Glostrup, Denmark). The Cox regression hazards method was used for multifactorial analysis. RESULTS: Nuclear accumulation of p53 was detected in 34 of 82 samples (41.5%). Clinical lymph node N stage (p = 0.045), lymphatic (p <0.001) and venous (p = 0.04) embolization by neoplastic cells, p53 positivity (p = 0.012) and p53 grade (p = 0.004) were significantly associated with lymph node metastasis. Followup was 0.1 to 453 months (mean 88.7). Multivariate analysis revealed that only lymphatic embolization (relative risk 9.4, 95% confidence interval [CI] 2.8 to 31.6) and p53 positivity (relative risk 4.8, 95% CI 1.6 to 14.9) were independent factors for lymph node metastasis. Patients with negative p53 had significantly better 5 and 10-year overall survival than those in whom tumors stained positive for p53 (64.5% and 54.6% versus 30.2% and 26.4%, respectively, p = 0.009). When tumors were p53 positive and HPV DNA positive, overall survival was worse. Multivariate analysis revealed that only age (relative risk 2.9, 95% CI 1.6 to 5.1) and lymph node metastasis (relative risk 3.2, 95% CI 1.8 to 5.8) were independent risk factors for death. CONCLUSIONS: Immunoreactivity of p53 is an independent factor for lymph node metastasis. The association of positive p53 with positive HPV DNA was related to a worse prognosis.

Adult↗