Triple-negative breast tumours (TNBTs) make up 15–20% of all breast tumours. There is no treatment for them, and the role that cancer stem cells (CSCs) have in carcinogenesis is still unclear, so finding markers and therapeutic targets in CSC exosomes requires these cells to exist as a homogeneous cell population. The objective of this work was to determine differences in ultrastructural morphology, proliferative capacity, and mouse-xenotransplantation characteristics of the MDA-MB-231 and MDA-MB-436 TNBT cell lines with the CD44high/CD24low phenotype in order to study their exosomes. The results show that the CD44high/CD24low MBA-MB-231 cells had a population doubling time of 41.56 h, compared to 44.79 h in the MDA-MB-436 cell line. After magnetic immunoseparation, 18.75% and 14.56% of the stem cell population of the MDA-MB-231 and MDA-MB-436 cell lines, respectively, were of the CD44high/CD24low phenotype, which were expanded to reach purities of 80.4% and 87.6%. The same expanded lineage in both cell lines was shown to possess the pluripotency markers Nanog and Oct4. Under a scanning electron microscope, the CD44high/CD24low lineage of the MBA-MD-231 cell line formed groups of more interconnected cells than this lineage of the MBA-MD-436 line. A total of 16% of the mice inoculated with the CD44high/CD24low lineage of either cell line presented tumours of the breast, lung, and submandibular ganglia, in whose tissues variable numbers of inoculated cells were found 30 days post-inoculation. By magnetic immunoselection, it was possible to isolate in similar quantities and characterize, expand, and xenotransplant the CD44high/CD24low lineage of the MDA-MB-231 and MDA-MB-436 cell lines. The former cell line has greater proliferative capacity, the two lines differ under scanning electron microscopy in how they intercommunicate, and both cell lines induce new tumours in mice and persist at least 30 days post-inoculation in the transplanted animal so their exosomes would also be different.

Background and Aim: Ribonucleic acid viruses remain latent in different cell types, including mesenchymal stem cells; however, the distemper virus remains undetected in these cells. This study aimed to determine whether adipose stem cells (ASCs) from dogs with distemper disease are infected with the canine morbillivirus (CM). Materials and Methods: Twelve dogs with the neurological phase of the disease and who were positive for CM by reverse transcription polymerase chain reaction (RT-PCR), were studied. ASCs from adipose tissue of the lesser omentum of these infected dogs were isolated and characterized. Direct fluorescence was used to detect the viral antigen in cell cultures. Flow cytometry and RT-PCR identified detectable quantities of the virus in two cultures, while electron microscopy confirmed the CM particles within ASCs. Results: This study revealed that ASCs of the omentum of dogs with distemper disease can be infected with CM, indicating their possible involvement in this virus latency and persistence. This suggests that its detection should be considered within the quality control process of stem cells intended for regenerative medicine. Conclusion: To the best of our knowledge, this is the first study that demonstrates that omentum ASCs from dogs with distemper disease can be infected with CM and may be involved in viral latency or persistence. Our study also suggests that the detection of CM should be considered within the quality control process of stem cells intended for regenerative medicine.

Stem cell therapy in dogs has increased considerably in recent years; however, there are few publications on the treatment of perianal fistulas (PF) in this species. The aim of this open-label clinical trial was to demonstrate the efficacy and safety of a new protocol for the in situ administration of low-dose adipose-derived allogeneic stem cells (ASCs) for the treatment of refractory spontaneous perianal fistula. The methodology consisted of applying one to three doses of 5 × 10⁶ cryopreserved allogeneic ASCs to each fistula. The study was performed in 14 dogs regardless of sex, breed, or age, with a clinical diagnosis of refractory PF. Cells diluted in phosphate-buffered saline were applied to five sites of the PF in an amount of 1 × 10⁶ per application site. Efficacy was determined by the complete closure of the fistula, which was observed in 100% of the cases studied one month after therapy, with a subsequent follow-up of 12 to 48 months after therapy. Furthermore, safety was demonstrated by the absence of local or systemic adverse effects. In conclusion, the protocol used in this work demonstrates the efficacy without adverse effects of the in situ application of low doses of allogeneic ASCs, providing a simple, non-invasive, long-lasting and low-cost therapeutic option.

Carrion's disease is a neglected endemic disease found in remote Andean areas. As an overlooked disease, knowledge of innate immune responses to Bartonella bacilliformis, the etiological agent, is scarce. This study aimed to evaluate the cytokine response to B. bacilliformis using in vitro human peripheral blood mononuclear cells (PBMCs) stimulations. PBMCs from naive adults were isolated by gradient centrifugation and cocultured with heat-inactivated (HI) B. bacilliformis at different incubation times (3, 6, 12, 24, and 36 h). Cytokines, chemokines, and growth factors were determined in culture supernatants by multiplex fluorescent bead-based quantitative suspension array technology. During the first 36 h, a proinflammatory response was observed, including tumor necrosis factor-α, interleukin (IL)-1α, IL-1β, interferon-α2, and IL-6, followed by an anti-inflammatory response mainly related to IL-1RA. Moreover, high expression levels of chemokines IL-8, monocyte chemoattractant protein-1α, and macrophage inflammatory protein (MIP)-1β were detected from 3 h poststimulation and MIP-1α was detected at 24 h. Some growth factors, mainly granulocyte macrophage colony-stimulating factor and granulocyte colony-stimulating factor, and in minor concentrations vascular endothelial growth factor, epidermal growth factor, and eotaxin, were also detected. Innate response to HI B. bacilliformis stimulation consists of a rapid and strong proinflammatory response characterized by a wide range of cytokines and chemokines followed by an anti-inflammatory response and increased specific growth factors.

Stem cell therapy in canines has increased considerably in recent years; however, there are few publications on the treatment of perianal fistulas (PF) in this species, and there is no agreed protocol for the number of cells per dose and their repetitions, nor for the in situ delivery methodology and follow-up period after cell therapy. The aim of this open-label clinical trial was to demonstrate the efficacy and safety of a new protocol for in situ administration of low-dose, expanded and cryopreserved allogeneic adipose-derived stem cells for the treatment of refractory spontaneous perianal fistula. The methodology consisted of intralesional application of 1 to 3 doses - depending on evidence of clinical signs of recurrence - of 5x106 cryopreserved allogeneic adipose-derived allogeneic stem cells in each fistula. The study was conducted in 14 dogs regardless of sex, breed or age with a clinical diagnosis of refractory PF presented between January 2019 and December 2023. Cells were diluted in 1 mL of phosphate-buffered saline and this volume was applied to five sites at the edge of the FP in an amount of 1x106 per application site. The evolution of the fistula was followed for 12 to 48 months. Efficacy was determined by complete healing as evidenced by complete closure of the fistula, which was observed in 100% of the cases studied one month after therapy, with a subsequent follow-up of 12 to 48 months after therapy. In addition, there were no local or systemic adverse effects assessed by clinical examination, complete blood count and blood biochemistry. In conclusion, the protocol used in this work demonstrates the efficacy without adverse effects of in situ application of allogeneic adipose-derived adipose stem cells in low doses and cell replicates to treat canine refractory PF, providing a simple, non-invasive, long-lasting and low-cost therapeutic option.

Background: Consider this Carrion's disease (CD) is a biphasic illness—comprising acute and chronic phases—endemic to Peru and caused by Bartonella bacilliformis , a bacterium transmitted by sandflies. Despite its clinical relevance, the mechanisms underlying innate immune activation in response to B. bacilliformis remain poorly understood. Toll-like receptors (TLRs) play a central role in recognizing conserved molecular patterns present in pathogens, thereby initiating innate immune responses. The present study aimed to describe the expression patterns of TLR2 and TLR4, along with cytokine secretion profiles, during peripheral blood mononuclear cells (PBMCs) exposure to B. bacilliformis . Methods: Peripheral blood mononuclear cells (PBMCs) from healthy donors were stimulated with heat-inactivated B. bacilliformis (ATCC 35685 strain), zymosan (TLR2 control), or E. coli LPS (TLR4 control). TLR2 and TLR4 gene expression was quantified by RT-qPCR at 0, 12, 24, 36, and 48 h. Cytokines were measured using a 17-plex panel. Analyses were descriptive, using non-parametric statistics. Results: Results elicited measurable changes in the transcriptional expression of TLR2 and TLR4 during stimulation, with peak activation typically observed at 12 h, although in one case the maximal response was delayed to 24 h. These expression changes coincided with significant modulation of multiple cytokines, including pro-inflammatory mediators (TNF-α, IL-17, IL-12p70), Th1/Th2 cytokines (IFN-γ, IL-2, IL-5, IL-13), regulatory cytokines (IL-10), and growth factors (GM-CSF, IL-7). Conclusions: This exploratory study describes the transcriptional expression patterns of TLR2 and TLR4 and the accompanying cytokine responses in PBMCs exposed to B. bacilliformis . These profiles expand current knowledge of the early innate immune signature elicited by this neglected pathogen and provide a foundation for future studies using receptor-specific functional assays. Importantly, these patterns likely reflect early innate immune response signatures rather than definitive evidence of functional receptor activation.