Pilot Study by Liquid Biopsy in Gastrointestinal Stromal Tumors: Analysis of PDGFRA D842V Mutation and Hypermethylation of SEPT9 Presence by Digital Droplet PCR.

Tissue biopsy remains the standard for diagnosing gastrointestinal stromal tumors (GISTs), although liquid biopsy is emerging as a promising alternative in oncology. In this pilot study, we advocate for droplet digital PCR (ddPCR) to diagnose GIST in tissue samples and explore its potential for early diagnosis via liquid biopsy, focusing on the PDGFRA D842V mutation and SEPT9 hypermethylated gene. We utilized ddPCR to analyze the predominant PDGFRA mutation (D842V) in surgical tissue samples from 15 GIST patients, correlating with pathologists' diagnoses. We expanded our analysis to plasma samples to compare DNA alterations between tumor tissue and plasma, also investigating SEPT9 gene hypermethylation. We successfully detected the PDGFRA D842V mutation in GIST tissues by ddPCR. Despite various protocols to enhance mutation detection in early-stage disease, it remained challenging, likely due to the low concentration of DNA in plasma samples. Additionally, the results of Area Under the Curve (AUC) for the hypermethylated SEPT9 gene, analyzing concentration, ratio, and abundance were 0.74 (95% Confidence Interval (CI): 0.52 to 0.97), 0.77 (95% CI: 0.56 to 0.98), and 0.79 (95% CI: 0.59 to 0.99), respectively. As a rare disease, the early detection of GIST through such biomarkers is particularly crucial, offering significant potential to improve patient outcomes.

A Protocol for the Isolation of Oval Cells without Preconditioning.

Oval cells (OCs) is the name of hepatic progenitor cells (HPCs) in rodents. They are a small population of cells in the liver with the remarkable ability to proliferate and regenerate hepatocytes and cholangiocytes in response to acute liver damage. Isolating OCs generally requires a pretreatment with special diets, chemicals, and/or surgery to induce hepatic damage and OC proliferation in mice. Unfortunately, these pretreatments are not only painful for the mice but also increase the cost of the assays, and the effects on the different organs as well as on various liver cells are still unclear. Therefore, the search for a protocol to obtain OCs without prior liver damage is mandatory. In our study, we present a protocol to isolate murine OCs from healthy liver (HL-OCs) and compare them with OCs isolated from mice pretreated with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC-OCs). Our results demonstrated that cells derived from untreated mice exhibited similar behavior to those from treated mice in terms of surface marker expression, proliferation, and differentiation capacity. Therefore, given the impracticability of isolating human cells with prior hepatotoxic treatment, our model holds promise for enabling the isolation of progenitor cells from human tissue in the future. This advancement could prove invaluable for translational medicine in the understanding and treatment of liver diseases.

Study of the Effect of Wild-Type and Transiently Expressing CXCR4 and IL-10 Mesenchymal Stromal Cells in a Mouse Model of Peritonitis.

Sepsis due to peritonitis is a process associated with an inflammatory state. Mesenchymal stromal cells (MSCs) modulate the immune system due to the paracrine factors released and may be a therapeutic alternative. Three treatment groups were developed in a murine model of peritonitis to verify the effect of human adipose mesenchymal stem cell (hASCs). Additionally, a temporary modification was carried out on them to improve their arrival in inflamed tissues (CXCR4), as well as their anti-inflammatory activity (IL-10). The capacity to reduce systemic inflammation was studied using a local application (peritoneal injection) as a treatment route. Comparisons involving the therapeutic effect of wild-type ASCs and ASCs transiently expressing CXCR4 and IL-10 were carried out with the aim of generating an improved anti-inflammatory response for sepsis in addition to standard antibiotic treatment. However, under the experimental conditions used in these studies, no differences were found between both groups with ASCs. The peritoneal administration of hASCs or genetically modified hASCs constitutes an efficient and safe therapy in our model of mouse peritonitis.

Comparative Analysis Between Mesenchymal Stem Cells From Subcutaneous Adipose Tissue and Omentum in Three Types of Patients: Cancer, Morbid Obese and Healthy Control.

Objective. The aims of this study are to compare 2 origins of adipose-derived mesenchymal stem cells (MSCs) (omentum and subcutaneous) from 2 pathologies (morbid obesity and cancer) vs healthy donors. Adipose tissue has revealed to be the ideal MSC source. However, in developing adipose-derived stem cells (ASCs) for clinical use, it is important to consider the effects of different fat depots and also the effect of donor variability. Methods. We isolated and characterized the membrane markers and differentiation capacities of ASCs obtained from patients with these diseases and different origin. During the culture period, we further analysed the cells' proliferation capacity in an in vitro assay as well as their secretome. Results. Adipose-derived stem cells isolated from obese and cancer patients have mesenchymal phenotype and similar cell proliferation as ASCs derived from healthy donors, some higher in cells derived from subcutaneous fat. However, cells from these 2 types of patients do not have the same differentiation potential, especially in cancer patients from omentum, and exhibit distinct secretion of both pro-inflammatory and regulatory cytokines, which could explain the differences in use due to origin as well as pathology associated with the donor. Conclusion. Subcutaneous and omentum ASCs are slightly different; omentum generates fewer cells but with greater anti-inflammatory capacity. Adipose-derived stem cells from patients with either obesity or cancer are slightly altered, which limits their therapeutic properties.

Non-dividing Cell Virtosomes Affect In Vitro and In Vivo Tumour Cell Replication.

In vitro studies of partially purified virtosomes from rat liver showed inhibition of cell multiplication in four normal and two tumour cell lines. In vivo, the liver virtosomes slowed tumour growth and limited metastases in rats bearing DHD/K12-PROb cell initiated tumours.

Implication of stem cells from adipose tissue in wound healing in obese and cancer patients.

OBJECTIVE: Certain diseases such as obesity and cancer can cause impaired wound healing. Adipose tissue derived stem cells (ASCs) are a novel field of research. Many studies have evidenced their high degree of safety and potential for wound repair due to their immunomodulatory and tissue-regeneration properties. The purpose of this study is to determine the impact of obesity and cancer on the therapeutic potential of ASCs. MATERIALS AND METHODS: We isolated and characterized the phenotype, differentiation capacities, secretome, and in vitro migration capacities of ASCs. Furthermore, we analyze their capacity of in vitro migration associated with the plasma of the different patients. RESULTS: We observed that ASCs isolated from obese and cancer patients have the same phenotype, cell proliferation, and migration capacities as ASCs derived from healthy donors. However, they do not have the same differentiation potential and exhibit distinct profiles of both pro-inflammatory and regulatory secreted cytokines, which, together with the signals received from the bloodstream, could account for the impaired healing in patients with these diseases. CONCLUSIONS: We consider the ASCs from patients with either obesity or cancer are slightly altered, and this may be the cause of worse wound healing in these patients.

OBJETIVO: Enfermedades como la obesidad y el cáncer pueden alterar la cicatrización de las heridas. Las células madre derivadas del tejido adiposo (ASC) abren un nuevo campo de investigación ya que muchos estudios han demostrado su utilidad y alto grado de seguridad para la reparación de heridas debido a sus propiedades inmunomoduladoras y de regeneración tisular. El propósito de este estudio es determinar el impacto de la obesidad y el cáncer en el potencial terapéutico de las ASCs. MATERIAL Y MÉTODOS: Aislamos y caracterizamos el fenotipo, la capacidad de diferenciación, el secretoma y la capacidad de migración in vitro de las ASC. Asimismo, analizamos la capacidad de migración in vitro asociada al plasma de los diferentes pacientes. RESULTADOS: Observamos que las ASC aisladas de pacientes obesos y con cáncer tienen el mismo fenotipo, proliferación celular y capacidades de migración que las ASCaisladas de donantes sanos. Sin embargo, no tienen el mismo potencial de diferenciación y exhiben perfiles distintos de citoquinas secretadas tanto proinflamatorias como reguladoras. CONCLUSIONES: Consideramos que las ASC de pacientes con obesidad o cáncer están levemente alteradas. Esta puede ser la causa de una peor cicatrización de las heridas en este tipo de pacientes.

Oncological transformation in vitro of hepatic progenitor cell lines isolated from adult mice.

Colorectal cancer cells can transfer the oncogene KRAS to distant cells, predisposing them to malignant transformation (Genometastasis Theory). This process could contribute to liver metastasis; besides, hepatic progenitor cells (HPCs) have been found to be involved in liver malignant neoplasms. The objective of this study is to determine if mouse HPCs-Oval cells (OCs)-are susceptible to incorporate Kras GAT (G12D) mutation from mouse colorectal cancer cell line CT26.WT and if OCs with the incorporated mutation behave like malignant cells. To achieve this, three lines of OCs in different conditions were exposed to CT26.WT cells through transwell co-culture for a week. The presence of KrasG12D and capacity to form tumors were analyzed in treated samples by droplet digital PCR and colony-forming assays, respectively. The results showed that the KrasG12D mutation was detected in hepatic culture conditions of undifferentiated OCs and these cells were capable of forming tumors in vitro. Therefore, OCs are susceptible to malignant transformation by horizontal transfer of DNA with KrasG12D mutation in an undifferentiated condition associated with the liver microenvironment. This study contributes to a new step in the understanding of the colorectal metastatic process.

Main histological parameters to be evaluated in an experimental model of myocardial infarct treated by stem cells on pigs.

Myocardial infarction has been carefully studied in numerous experimental models. Most of these models are based on electrophysiological and functional data, and pay less attention to histological discoveries. During the last decade, treatment using advanced therapies, mainly cell therapy, has prevailed from among all the options to be studied for treating myocardial infarction. In our study we wanted to show the fundamental histological parameters to be evaluated during the development of an infarction on an experimental model as well as treatment with mesenchymal stem cells derived from adipose tissue applied intra-lesionally. The fundamental parameters to study in infarcted tissue at the histological level are the cells involved in the inflammatory process (lymphocytes, macrophages and M2, neutrophils, mast cells and plasma cells), neovascularization processes (capillaries and arterioles) and cardiac cells (cardiomyocytes and Purkinje fibers). In our study, we used intramyocardial injection of mesenchymal stem cells into the myocardial infarction area 1 hour after arterial occlusion and allowed 1 month of evolution before analyzing the modifications on the normal tissue inflammatory infiltrate. Acute inflammation was shortened, leading to chronic inflammation with abundant plasma cells and mast cells and complete disappearance of neutrophils. Another benefit was an increase in the number of vessels formed. Cardiomyocytes and Purkinje fibers were better conserved, both from a structural and metabolic point of view, possibly leading to reduced morbidity in the long term. With this study we present the main histological aspects to be evaluated in future assays, complementing or explaining the electrophysiological and functional findings.

Rat model of anal sphincter injury and two approaches for stem cell administration.

AIM: To establish a rat model of anal sphincter injury and test different systems to provide stem cells to injured area. METHODS: Adipose-derived stem cells (ASCs) were isolated from BDIX rats and were transfected with green fluorescent protein (GFP) for cell tracking. Biosutures (sutures covered with ASCs) were prepared with 1.5 x 106 GFP-ASCs, and solutions of 106 GFP-ASCs in normal saline were prepared for injection. Anorectal normal anatomy was studied on Wistar and BDIX female rats. Then, we designed an anal sphincter injury model consisting of a 1-cm extra-mucosal miotomy beginning at the anal verge in the anterior middle line. The sphincter lesion was confirmed with conventional histology (hematoxylin and eosin) and immunofluorescence with 4', 6-diamidino-2-phenylindole (commonly known as DAPI), GFP and α-actin. Functional effect was assessed with basal anal manometry, prior to and after injury. After sphincter damage, 36 BDIX rats were randomized to three groups for: (1) Cell injection without repair; (2) biosuture repair; and (3) conventional suture repair and cell injection. Functional and safety studies were conducted on all the animals. Rats were sacrificed after 1, 4 or 7 d. Then, histological and immunofluorescence studies were performed on the surgical area. RESULTS: With the described protocol, biosutures had been covered with at least 820000-860000 ASCs, with 100% viability. Our studies demonstrated that some ASCs remained adhered after suture passage through the muscle. Morphological assessment showed that the rat anal anatomy is comparable with human anatomy; two sphincters are present, but the external sphincter is poorly developed. Anal sphincter pressure data showed spontaneous, consistent, rhythmic anal contractions, taking the form of "plateaus" with multiple twitches (peaks) in each pressure wave. These basal contractions were very heterogeneous; their frequency was 0.91-4.17 per min (mean 1.6980, SD 0.57698), their mean duration was 26.67 s and mean number of peaks was 12.53. Our morphological assessment revealed that with the aforementioned surgical procedure, both sphincters were completely sectioned. In manometry, the described activity disappeared and was replaced by a gentle oscillation of basal line, without a recognizable pattern. Surprisingly, these findings appeared irrespective of injury repair or not. ASCs survived in this potentially septic area for 7 d, at least. We were able to identify them in 84% of animals, mainly in the muscular section area or in the tissue between the muscular endings. ASCs formed a kind of "conglomerate" in rats treated with injections, while in the biosuture group, they wrapped the suture. ASCs were also able to migrate to the damaged zone. No relevant adverse events or mortality could be related to the stem cells in our study. We also did not find unexpected tissue growths. CONCLUSION: The proposed procedure produces a consistent sphincter lesion. Biosutures and injections are suitable for cell delivery. ASCs survive and are completely safe in this clinical setting.

A Preliminary Study of the Action of Virtosomes from Non-dividing Cells on Tumour Cell Replication in vitro and in vivo.

BACKGROUND: A DNA-RNA-lipoprotein complex, termed as virtosome, is released spontaneously from healthy human, other mammalian, avian, amphibian and plant cells in a regulated and energy-dependent manner. Studies on human and mouse lymphocytes, hepatocytes, NIH 3T3 cells and mouse tumour cell lines have shown that virtosomes may be acting as inter-cellular messengers. In particular, virtosomes from non-dividing cells blocked 3H-thymidine incorporation into DNA in tumour cell lines. OBJECTIVE: Study of the effect of virtosomes on tumors "in vivo" and "in vitro". METHODS AND RESULTS: The present study shows in vitro effects of virtosomes isolated from rat liver, essentially nondividing cell populations, on cultures of healthy smooth muscle cells (SMC), human umbilical vein endothelial cells (HUVEC), human fibroblasts (h-fibroblasts) and mouse embryonic fibroblasts (NIH-3T3) together with two tumour cell lines, human Duke's type B colorectal adenocarcinoma cells (SW480) and human connective tissue fibrosarcoma cells (HT1080). Multiplication of all cell lines was inhibited by the liver virtosomal preparation even with various dilutions of the extract (100 - 0.5%). In an in vivo study, tumours were initiated by subcutaneous injection of 1.0 x 106 DHD/K12-PROb cells in 6 weeks old male BIDX rats. Visible tumours (<1cm) appeared after 3 weeks and lung metastases after 8 weeks (80%). Virtosomes introduced via a tail vein on tumour initiation resulted in a reduction in tumour size and number. CONCLUSION: Virtosomal preparation from a non-dividing cell population inhibited cell division, reduced tumour size and partially blocked metastasis.

Detection of KRAS G12D in colorectal cancer stool by droplet digital PCR.

AIM: To assess KRAS G12D mutation detection by droplet digital PCR (ddPCR) in stool-derived DNA from colorectal cancer (CRC) patients. METHODS: In this study, tumor tissue and stool samples were collected from 70 patients with stage I-IV CRC diagnosed by preoperative biopsy. KRAS mutational status was determined by pyrosequencing analysis of DNA obtained from formalin-fixed paraffin-embedded (FFPE) tumor tissues. The KRAS G12D mutation was then analyzed by ddPCR in FFPE tumors and stool-derived DNA from patients with this point mutation. Wild-type (WT) tumors, as determined by pyrosequencing, were included as controls; analysis of FFPE tissue and stool-derived DNA by ddPCR was performed for these patients as well. RESULTS: Among the total 70 patients included, KRAS mutations were detected by pyrosequencing in 32 (45.71%), whereas 38 (54.29%) had WT tumors. The frequency of KRAS mutations was higher in left-sided tumors (11 located in the right colon, 15 in the left, and 6 in the rectum). The predominant point mutation was KRAS G12D (14.29%, n = 10), which was more frequent in early-stage tumors (I-IIA, n = 7). In agreement with pyrosequencing results, the KRAS G12D mutation was detected by ddPCR in FFPE tumor-derived DNA, and only a residual number of mutated copies was found in WT controls. The KRAS G12D mutation was also detected in stool-derived DNA in 80% of all fecal samples from CRC patients with this point mutation. CONCLUSION: ddPCR is a reliable and sensitive method to analyze KRAS G12D mutation in stool-derived DNA from CRC patients, especially at early stages. This non-invasive approach is potentially applicable to other relevant biomarkers for CRC management.

Sutures enriched with adipose-derived stem cells decrease the local acute inflammation after tracheal anastomosis in a murine model.

OBJECTIVES: Local inflammatory reaction and tension are the main causes of postoperative complications after tracheal surgery. Adipose-derived stem cells (ASCs) are known to have immunomodulatory activity. The exact mechanism of this activity is not known, although it is possible that they modulate the function of different cells involved in the immune response. Little is known of their impact on acute inflammation, especially in the problematic tracheal area. We aimed to study the effect of ASCs applied locally in an animal model of tracheal resection and anastomosis. METHODS: ASCs from the subcutaneous fat of BDIX rats were infected for expression of the enhanced green fluorescent protein (eGFP) and were cultured with Polyglactin 910 sutures to obtain biosutures (ASC-coated sutures). After tracheal resection, 90 BDIX rats (syngeneic, autologous model) underwent anastomosis with biosutures (1.5 10(6) cells/biosuture [Group 1] or 0.5 10(6) cells/biosuture [Group 2]) or conventional sutures (Group 3). The animals were killed after 1, 4, 10, 30 or 60 days and histological and immunofluorescence studies were performed on the anastomotic areas. Inflammatory cell densities were graded semiquantitatively by the pathologist in a blinded fashion. RESULTS: In the early period (1 and 4 days), the biosuture groups presented an atypical pattern of acute inflammation, characterized by the almost complete absence of neutrophils, and the presence of abundant lymphocytes and plasma cells, compared with the control group (P < 0.05). Moreover, abundant macrophages/monocytes were immunolocated around blood vessels near the biosutures and between biosuture threads 1 day after anastomosis, whereas the presence of macrophages/monocytes in animals treated with conventional sutures was discrete (P < 0.05). No differences were observed in the later period. No side effects in the biosuture groups were found. CONCLUSIONS: Biosutures are a comfortable way of stem cell delivery to the surgical field without modification of the operative protocol. ASCs suppress the local acute inflammatory reaction (increased macrophage migration and decreased neutrophil infiltration) in the tracheal anastomosis and cause an early switch from acute to chronic inflammation.