GUEVARA RAMÍREZ, ALEXANDRA PATRICIA
Preferred name
GUEVARA RAMÍREZ, ALEXANDRA PATRICIA
Main Affiliation
CIGG - Centro de Investigación Genética y Genómica
Web Site
ORCID
0000-0002-4829-3653
Scopus Author ID
57195725827
75 results
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Item type:Publication, Molecular Mechanisms and Therapeutic Perspectives of Gut Microbiota, Autophagy, and Apoptosis in Cholangiocarcinoma PathophysiologyCholangiocarcinoma (CCA) is an aggressive malignancy of the biliary tract with rising global incidence and limited treatment options. Its pathogenesis involves a complex interplay of genetic mutations, epigenetic dysregulation, inflammatory signaling, and environmental influences. Emerging evidence highlights the pivotal role of the gut–liver axis and microbiota dysbiosis in shaping biliary homeostasis and disease progression. Alterations in microbial composition disrupt apoptosis and autophagy, two key processes regulating cell survival and death, thereby contributing to tumorigenesis, metastasis, and therapy resistance. Specific taxa, including Enterococcus, Escherichia coli, Pseudomonas, Bifidobacterium, and Bacillus, demonstrate strain-dependent effects, acting either as tumor promoters through genotoxic metabolites and immune evasion or as potential tumor suppressors by inducing apoptosis and immune activation. These findings underscore the context-dependent roles of microbiota in CCA biology. Importantly, microbiota modulation offers novel therapeutic opportunities. Dietary interventions such as probiotics, prebiotics, and nutritional strategies, alongside innovative microbiome-targeted therapies, hold promise for restoring microbial balance, enhancing antitumor immunity, and improving patient outcomes. This review integrates current molecular and microbiological evidence to propose the gut microbiota as both a biomarker and a therapeutic target in CCA, opening avenues for precision medicine approaches in hepatobiliary oncologyScopus© Citations 2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Identification of mutations on the EMD and EYA4 genes associated with Emery–Dreifuss muscular dystrophy and deafness: a case report(Frontiers Media SA, 2023-05-12); ; ; José Luis Laso-Bayas<jats:sec><jats:title>Introduction</jats:title><jats:p>Hearing loss is the most common sensory disability, and it is estimated that 50% of cases are caused by genetic factors. One of the genes associated with deafness is the eyes absent homolog 4 (<jats:italic>EYA4</jats:italic>) gene, a transcription factor related to the development and function of the inner ear. Emery–Dreifuss muscular dystrophy is a rare inherited disease characterized by atrophy and weakness of the humeroperoneal muscles, multi-joint contractures, and cardiac manifestations. It is inherited in an autosomal-dominant, X-linked, or less frequently autosomal recessive manner; one of the genes associated with EDMD is the emerin (<jats:italic>EMD)</jats:italic> gene.</jats:p></jats:sec><jats:sec><jats:title>Case description</jats:title><jats:p>A total of two Ecuadorian siblings aged 57 (Subject A) and 55 (Subject B) were diagnosed with deafness and an unspecified type of muscular dystrophy based on family history and clinical findings. Next-generation sequencing (NGS) using the TruSight Cardio and Inherited Disease kits at the Centro de Investigación Genética y Genómica CIGG, Universidad UTE, was performed. The genetic analyses showed two mutations: a stop mutation in exon 11/20 (NM_004100.4:c.940G&gt;T) of the <jats:italic>EYA4</jats:italic> gene and a missense mutation in exon 6 (NM_000117.2:c.548C&gt;G) of the <jats:italic>EMD</jats:italic> gene.</jats:p></jats:sec><jats:sec><jats:title>Discussion and conclusion</jats:title><jats:p>The <jats:italic>in silico</jats:italic> predictions described the <jats:italic>EYA4</jats:italic> variant as likely pathogenic and the <jats:italic>EMD</jats:italic> variant as a variant of uncertain significance (VUS). Moreover, an ancestry analysis was performed using 46 Ancestry Informative Insertion/Deletion Markers (AIM-InDels), and the ancestral composition of subject A was 46% African, 26.1% European, and 27.9% American Indian ancestry, whereas the ancestral composition of subject B was 41.3% African, 38.2% European, and 20.5% American Indian ancestry. The present case report describes two Ecuadorian siblings with a mainly African ancestral component, muscular dystrophy, and deafness phenotypes. Moreover, using next-generation sequencing (NGS), a mutation in the <jats:italic>EMD</jats:italic> and a novel mutation in <jats:italic>EYA4</jats:italic> genes possibly associated with the subjects' phenotype were identified and discussed.</jats:p></jats:sec>Scopus© Citations 3 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The Non-Coding rs5945619 Variant at Xp11.22 and Its Putative Regulatory Effects on Nearby Genes in Ecuadorian Mestizo Women with Breast Cancer: A Case Series and In Silico Cis-eQTL Analysis(MDPI AG, 2026-08-07); ; ; ; Ruiz-Pozo, Viviana A. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of diet on the microbiota and immune system in patients with systemic lupus erythematosus(Informa UK Limited, 2024-11-30); ; ; Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by widespread inflammation and organ damage. Studies indicate that diet significantly influences the gut microbiota, which, in turn, affects the immune system. This article explores gut microbiota dysbiosis in SLE patients and potential mechanisms related to dietary interventions and immune function. It highlights specific dietary patterns, such as a high-fibre diet and the Mediterranean diet, that may modulate the diversity and activity of the gut microbiota. The interaction between altered microbiota and immune responses, including the regulation of inflammatory cytokines, intestinal barrier permeability, and autoantibody production is examined. This review highlights the importance of personalized dietary strategies to modulate the diversity and activity of the gut microbiota by enhancing the immune response and potentially mitigating disease progression.Scopus© Citations 9 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A deep analysis using panel-based next-generation sequencing in an Ecuadorian pediatric patient with anaplastic astrocytoma: a case report(Springer Science and Business Media LLC, 2020-08-31); ; Santiago Guerrero<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>Anaplastic astrocytoma is a rare disorder in children from 10 to 14 years of age, with an estimated 0.38 new cases per 100,000 people per year worldwide. Panel-based next-generation sequencing opens new possibilities for diagnosis and therapy of rare diseases such as this one. Because it has never been genetically studied in the Ecuadorian population, we chose to genetically characterize an Ecuadorian pediatric patient with anaplastic astrocytoma for the first time. Doing so allows us to provide new insights into anaplastic astrocytoma diagnosis and treatment.</jats:p></jats:sec><jats:sec><jats:title>Case presentation</jats:title><jats:p>Our patient was a 13-year-old Mestizo girl with an extensive family history of cancer who was diagnosed with anaplastic astrocytoma. According to ClinVar, SIFT, and PolyPhen, the patient harbored 354 genomic alterations in 100 genes. These variants were mostly implicated in deoxyribonucleic acid (DNA) repair. The top five most altered genes were<jats:italic>FANCD2</jats:italic>,<jats:italic>NF1</jats:italic>,<jats:italic>FANCA</jats:italic>,<jats:italic>FANCI</jats:italic>, and<jats:italic>WRN.</jats:italic>Even though<jats:italic>TP53</jats:italic>presented only five mutations, the rs11540652 single-nucleotide polymorphism classified as pathogenic was found in the patient and her relatives; interestingly, several reports have related it to Li-Fraumeni syndrome. Furthermore,<jats:italic>in silico</jats:italic>analysis using the Open Targets Platform revealed two clinical trials for pediatric anaplastic astrocytoma (studying cabozantinib, ribociclib, and everolimus) and 118 drugs that target the patient’s variants, but the studies were not designed specifically to treat pediatric anaplastic astrocytoma.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>Next-generation sequencing allows genomic characterization of rare diseases; for instance, this study unraveled a pathogenic single-nucleotide polymorphism related to Li-Fraumeni syndrome and identified possible new drugs that specifically target the patient’s variants. Molecular tools should be implemented in routine clinical practice for early detection and effective preemptive intervention delivery and treatment.</jats:p></jats:sec>Scopus© Citations 2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Next-Generation sequencing in a Native American patient with sea-blue histiocytosis: A case report and genomic analysis(Medwave Estudios Limitada, 2025-08-08); ; ; This study presents a case of a 25-year-old Native American woman from Otavalo, Ecuador, diagnosed with sea-blue histiocytosis and myelodysplastic syndrome. Bone marrow aspiration revealed sea-blue histiocytes, and next-generation sequencing identified a likely pathogenic stop-gain mutation in the gene, associated with myelodysplastic syndrome. Additionally, variants of uncertain significance were found in the and genes. Ancestral analysis showed a predominantly Native American composition, suggesting a potential genetic predisposition specific to Andean communities. The report underscores the importance of understanding genetic and ancestral backgrounds in diagnosing and managing hematological disorders. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Impact of fundamental components of the Mediterranean diet on the microbiota composition in blood pressure regulation(Springer Science and Business Media LLC, 2024-05-03); ; ; ; Background: The Mediterranean diet (MedDiet) is a widely studied dietary pattern reflecting the culinary traditions of Mediterranean regions. High adherence to MedDiet correlates with reduced blood pressure and lower cardiovascular disease (CVD) incidence and mortality. Furthermore, microbiota, influenced by diet, plays a crucial role in cardiovascular health, and dysbiosis in CVD patients suggests the possible beneficial effects of microbiota modulation on blood pressure. The MedDiet, rich in fiber and polyphenols, shapes a distinct microbiota, associated with higher biodiversity and positive health effects. The review aims to describe how various Mediterranean diet components impact gut microbiota, influencing blood pressure dynamics. Main body: The MedDiet promotes gut health and blood pressure regulation through its various components. For instance, whole grains promote a healthy gut microbiota given that they act as substrates leading to the production of short-chain fatty acids (SCFAs) that can modulate the immune response, preserve gut barrier integrity, and regulate energy metabolism. Other components of the MedDiet, including olive oil, fuits, vegetables, red wine, fish, and lean proteins, have also been associated with blood pressure and gut microbiota regulation. Conclusion: The MedDiet is a dietary approach that offers several health benefits in terms of cardiovascular disease management and its associated risk factors, including hypertension. Furthermore, the intake of MedDiet components promote a favorable gut microbiota environment, which, in turn, has been shown that aids in other physiological processes like blood pressure regulation.Scopus© Citations 40 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Genes involved in damage response caused by UV radiation in Ecuadorian population of different altitude regions(Elsevier BV, 2019-12); ; Scopus© Citations 1 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Genotoxic and Carcinogenic Potential of Compounds Associated with Electronic Cigarettes: A Systematic Review(Hindawi Limited, 2019-12-23)Scopus© Citations 20 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, TCGA Pan-Cancer Genomic Analysis of Alternative Lengthening of Telomeres (ALT) Related Genes(MDPI AG, 2020-07-21); Paola E. Leone<jats:p>Telomere maintenance mechanisms (TMM) are used by cancer cells to avoid apoptosis, 85–90% reactivate telomerase, while 10–15% use the alternative lengthening of telomeres (ALT). Due to anti-telomerase-based treatments, some tumors switch from a telomerase-dependent mechanism to ALT; in fact, the co-existence between both mechanisms has been observed in some cancers. Although different elements in the ALT pathway are uncovered, some molecular mechanisms are still poorly understood. Therefore, with the aim to identify potential molecular markers for the study of ALT, we combined in silico approaches in a 411 telomere maintenance gene set. As a consequence, we conducted a genomic analysis of these genes in 31 Pan-Cancer Atlas studies from The Cancer Genome Atlas and found 325,936 genomic alterations; from which, we identified 20 genes highly mutated in the cancer studies. Finally, we made a protein-protein interaction network and enrichment analysis to observe the main pathways of these genes and discuss their role in ALT-related processes, like homologous recombination and homology directed repair. Overall, due to the lack of understanding of the molecular mechanisms of ALT cancers, we proposed a group of genes, which after ex vivo validations, could represent new potential therapeutic markers in the study of ALT.</jats:p>Scopus© Citations 13