Sebastian San martin

Dr. Sebastian San martin

Centro de Investigaciones Biomédicas, Escuela de Medicina-Facultad de Medicina, Doctorado en Ciencias e Ingeniería para la Salud, Universidad de Valparaíso, Viña del Mar, Chile
orcid

Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 February 2020 in Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease
Verified
Journal Article
Closed access
ICIvo Carrasco-Wong
Ivo Carrasco-Wong
AMAlejandra Moller
Alejandra Moller
FGFernanda R. Giachini
Fernanda R. Giachini
VLVictor V. Lima
Victor V. Lima
FTFernando Toledo
Fernando Toledo
SMSebastian San martin
Sebastian San martin

6 December 2007 in Journal of Anatomy
Verified
Journal Article
Open access
PDF file
FGF. R. C. Giachini
F. R. C. Giachini
Víctor CarrielVíctor Carriel
Víctor Carriel
LCL. P. Capelo
L. P. Capelo
RTRita de Cássia Tostes
Rita de Cássia Tostes
MCM. H. Carvalho
M. H. Carvalho
SMSebastian San martin
Sebastian San martin
During embryo implantation, invasive trophoblast cells mediate embryo invasion into the decidualized stroma, forming a rich network of lacunae that connect the embryonic tissues to the maternal blood vessels. Placentation is probably guided by the composition and organization of the endometrial extracellular matrix. Certain pathological conditions that occur during pregnancy, including diabetes, have been linked to abnormal placental morphology and consequent fetal morbidity. We used immunoperoxidase techniques to identify members of the collagen, proteoglycan and glycoprotein families in the various compartments of the rat placenta and to determine whether experimentally induced diabetes affects placental morphology and alters the distribution of these molecules during pregnancy. Single injections of alloxan (40 mg kg−1 i.v.) were used to induce diabetes on day 2 of pregnancy in Wistar rats. Placentas were collected on days 14, 17, and 20. Type I and III collagen, as well as the proteoglycans decorin and biglycan, were found to be distributed throughout the placentas of control and diabetic rats. In both groups, laminin expression decreased at the end of pregnancy. In contrast, fibronectin was detected in the labyrinth region of diabetic rats at all gestational stages studied, whereas it was detected only at term pregnancy in the placentas of control rats. These results show for the first time that some extracellular matrix molecules are modulated during placental development. However, as diabetic rats presented increased fibronectin deposition exclusively in the labyrinth region, we speculate that diabetes alters the microenvironment at the maternal–fetal interface, leading to developmental abnormalities in the offspring.

10 May 2022 in Molecules
Verified
Journal Article
Open access
PDF file
DRDaniel Rojo
Daniel Rojo
AMAlejandro Madrid
Alejandro Madrid
SMSebastian San martin
Sebastian San martin
MPMario Párraga
Mario Párraga
MPMaria Aparecida Silva Pinhal
Maria Aparecida Silva Pinhal
Manuel Valenzuela-ValderramaManuel Valenzuela-Valderrama
Manuel Valenzuela-Valderrama
The cancer-preventive agent Resveratrol (RSV) [3,5,4′-trihydroxytrans-stilbene] is a widely recognized antioxidant molecule with antitumoral potential against several types of cancers, including prostate, hepatic, breast, skin, colorectal, and pancreatic. Herein, we studied the effect of RSV on the cell viability and invasion potential of gastric cancer cells. AGS and MKN45 cells were treated with different doses of RSV (0–200 μM) for 24 h. Cell viability was determined using the Sulphorhodamine B dye (SRB) assay. For invasion assays, gastric cells were pre-treated with RSV (5–25 μM) for 24 h and then seeded in a Transwell chamber with coating Matrigel. The results obtained showed that RSV inhibited invasion potential in both cell lines. Moreover, to elucidate the mechanism implicated in this process, we analyzed the effects of RSV on SOD, heparanase, and NF-κB transcriptional activity. The results indicated that RSV increased SOD activity in a dose-dependent manner. Conversely, RSV significantly reduced the DNA-binding activity of NF-κB and the enzymatic activity of heparanase in similar conditions, which was determined using ELISA-like assays. In summary, these results show that RSV increases SOD activity but decreases NF-kB transcriptional activity and heparanase enzymatic activity, which correlates with the attenuation of invasion potential in gastric cancer cells. To our knowledge, no previous study has described the effect of RSV on heparanase activity. This article proposes that heparanase could be a key effector in the invasive events occurring during gastric cancer metastasis.

Verified
Journal Article
Open access
PDF file
FTFelipe Andrés Troncoso Troncoso
Felipe Andrés Troncoso Troncoso
KHKurt Herlitz
Kurt Herlitz
JAJesenia Acurio
Jesenia Acurio
Claudio AguayoClaudio Aguayo
Claudio Aguayo
KGKatherine Guevara
Katherine Guevara
Carlos EscuderoCarlos Escudero
Carlos Escudero
Estrogenic steroids and adenosine A2A receptors promote the wound healing and angiogenesis processes. However, so far, it is unclear whether estrogen may regulate the expression and pro-angiogenic activity of A2A receptors. Using in vivo analyses, we showed that female wild type (WT) mice have a more rapid wound healing process than female or male A2A-deficient mice (A2AKO) mice. We also found that pulmonary endothelial cells (mPEC) isolated from female WT mice showed higher expression of A2A receptor than mPEC from male WT mice. mPEC from female WT mice were more sensitive to A2A-mediated pro-angiogenic response, suggesting an ER and A2A crosstalk, which was confirmed using cells isolated from A2AKO. In those female cells, 17β-estradiol potentiated A2A-mediated cell proliferation, an effect that was inhibited by selective antagonists of estrogen receptors (ER), ERα, and ERβ. Therefore, estrogen regulates the expression and/or pro-angiogenic activity of A2A adenosine receptors, likely involving activation of ERα and ERβ receptors. Sexual dimorphism in wound healing observed in the A2AKO mice process reinforces the functional crosstalk between ER and A2A receptors.

7 August 2017 in European Journal of Histochemistry
Verified
Journal Article
Open access
PDF file
MGMatias Garrido
Matias Garrido
CECamila Escobar
Camila Escobar
CZConstanza Zamora
Constanza Zamora
CRCarolina Rejas
Carolina Rejas
JVJuan Varas
Juan Varas
SMSandra Montedónico
Sandra Montedónico
Biliary atresia leads to cirrhosis in the vast majority of patients and constitutes the first cause of paediatric liver transplantation. Animal models allow us to understand the molecular basis and natural history of diseases. The aim of this study is to describe a surgically created animal model of biliary atresia with emphasis in long-term liver function. Forty-two 3-week-old Sprague-Dawley rats were randomly divided into two groups: bile duct ligature (BDL) and control. The animals were sacrificed on the 2nd, 4th, and 6th postoperative weeks. Blood samples were collected for liver function analysis. The spleen to body weight ratio was determined. Histopathological examination of liver tissue was performed by hematoxylin-eosin and Sirius red staining. Collagen quantification was determined by using colorimetric digital image analysis and was expressed as a percentage of total liver tissue area. Quantitative real-time polymerase chain reaction was performed to analyse gene expression levels of transforming growth factor-β1 (Tgfb1) and apeline (Apln) genes. Statistical analysis was performed where P<0.05 was considered significant. Animals from BDL group developed increasing cholestasis with clinical and laboratory features. Splenomegaly was detected at 4th and 6th week (P<0.05). Histological evaluation of the liver showed ductular reaction, portal fibrosis and bile plugs. Collagen area to total liver tissue area had a median of 2.5% in the control group and 6.5 %, 14.3 % and 37.7 % in BDL rats at 2nd, 4th and 6th weeks respectively (P<0.001). Tgfb1 mRNA expression level was significantly higher at 6th week (P<0.001) in BDL group when compared to control. Apln mRNA expression level was significantly higher at 4th and 6th week (P<0.001) and showed a positive linear correlation (r = 0.975, P<0.05) in BDL group when compared to control. Bile duct ligature in young rats is an animal model that recreates clinical, laboratory, histological and molecular findings of biliary atresia. Bile duct ligature constitutes a good animal model to investigate therapeutic approaches for modifying the progression of liver fibrosis in biliary atresia.

26 November 2024 in Computation
Verified
Journal Article
Open access
PDF file
MLMariangel Del Carmen Rodriguez Leones
Mariangel Del Carmen Rodriguez Leones
CLClaudio Eduardo Cordova Lepe
Claudio Eduardo Cordova Lepe
IBIsabel Benjumeda
Isabel Benjumeda
SMSebastian San martin
Sebastian San martin
Cervical cancer (CC) remains a significant health issue, especially in low- and middle-income countries (LMICs). While Pap smears are the standard screening method, they have limitations, like low sensitivity and subjective interpretation. Liquid-based cytology (LBC) offers improvements but still relies on manual analysis. This study explored the potential of deep learning (DL) for automated cervical cell classification using both Pap smears and LBC samples. A novel image segmentation algorithm was employed to extract single-cell patches for training a ResNet-50 model. The model trained on LBC images achieved remarkably high sensitivity (0.981), specificity (0.979), and accuracy (0.980), outperforming previous CNN models. However, the Pap smear dataset model achieved significantly lower performance (0.688 sensitivity, 0.762 specificity, 0.8735 accuracy). This suggests that noisy and poor cell definition in Pap smears pose challenges for automated classification, whereas LBC provides better classifiable cells patches. These findings demonstrate the potential of AI-powered cervical cell classification for improving CC screening, particularly with LBC. The high accuracy and efficiency of DL models combined with effective segmentation can contribute to earlier detection and more timely intervention. Future research should focus on implementing explainable AI models to increase clinician trust and facilitate the adoption of AI-assisted CC screening in LMICs.