RESUMEN
Understanding the fundamental cell-material interactions is essential to designing functional materials for biomedical applications. Although mesenchymal stromal cells (MSCs) are known to secrete cytokines and exosomes that are effective to treat degenerative diseases, the inherent property of biomaterials to modulate the therapeutic function of MSCs remains to be investigated. Here, a multivalent cell-membrane adhesive conjugate was generated through polyamindoamine (PAMAM) and an oligopeptide, IKVAV, and the conjugate was further complexed with hyaluronic acid (HA). The adhesive particulates were used to coat the surface of adipose-derived mesenchymal stromal cells (Ad-MSCs) and studied in the MSC spheroid culture. The analysis showed that the adhesive complexes formed via PAMAM conjugates and HA significantly promoted the proliferation and the gene expression of pro-angiogenesis cytokines in MSCs; the production of anti-inflammatory miRNAs in exosomes could also be elevated. The transplantation of the Ad-MSCs primed with PAMAM-IKVAV/HA composite particulates in a rat myocardial infarction model further demonstrated the beneficial effects of membrane-binding materials on improving the cell retention and tissue angiogenesis. The new function of membrane-binding adhesive materials potentially provides useful ways to improve cell-based therapy.
Asunto(s)
Adhesivos/química , Adhesivos/farmacología , Células Madre Mesenquimatosas/efectos de los fármacos , Comunicación Paracrina/efectos de los fármacos , Animales , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Expresión Génica/efectos de los fármacos , Ácido Hialurónico/química , Inflamación/tratamiento farmacológico , Laminina/química , Masculino , Trasplante de Células Madre Mesenquimatosas , Infarto del Miocardio/tratamiento farmacológico , Neovascularización Fisiológica/efectos de los fármacos , Oligopéptidos/química , Fragmentos de Péptidos/química , Poliaminas/química , Ratas , Ratas Sprague-DawleyRESUMEN
OBJECTIVES: The aim was to define the role of chemotherapy in stage II nasopharyngeal carcinoma (NPC) and to identify the toxicity of chemotherapy for these patients in the era of intensity-modulated radiotherapy (IMRT). METHODS: Between January 2002 and December 2013, 169 patients with stage II NPC were analyzed. Of these patients, 149 patients treated with chemotherapy were divided into three groups as follows: neoadjuvant chemotherapy followed by IMRT (NCT) group, concurrent chemotherapy with IMRT (CCRT) group, and neoadjuvant chemotherapy followed by CCRT (NC+CCRT) group. In addition, 20 patients received IMRT alone. We retrospectively assessed the 10-year survival and acute adverse effects in the patients using SPSS software. RESULTS: The median follow-up time was 93 months (2-160 months). The 10-year OS of the NCT, CCRT, NC+CCRT groups vs the IMRT alone group was 69.8%, 63.4%, 69.7% vs 72.4%, respectively (P=0.664, 0.940, and 0.998, respectively). Both univariable and multivariable analyses showed that the addition of chemotherapy to IMRT did not significantly improve the 10-year survival outcomes. The hematotoxicity and mucous reaction of patients with chemotherapy were more serious than those with IMRT alone (P=0.007 and 0.049). Distant metastasis for stage II NPC patients mostly occurred within 3 years, which is very different from patients with advanced NPC. CONCLUSION: Patients with stage II NPC who are treated with IMRT may obtain satisfactory long-term survival outcomes. The additional chemotherapy cannot significantly increase survival; however, it may remarkably increase treatment-associated acute toxic reactions.
RESUMEN
The foreign-body response to biomaterials compromises the performance of many biomedical devices by severe fibrosis and limited neovascularization. Mesenchymal stem cells are known to secrete cytokines for treating inflammatory conditions. In this study, we aim to investigate whether the paracrine products of adipose-derived mesenchymal stem cells (ADSCs) can affect the microenvironment of biomaterials and improve tissue responses to biomaterial implants. A model system was built by loading ADSC spheroids into a macroencapsulation device composed of polytetrafluoroethylene (PTFE) filtration membranes. Soluble ADSC factors that diffused out of the device in vitro promoted the angiogenetic activity of endothelial cells and affected the secretion pattern of macrophages. In vivo study was carried out by subcutaneously embedding blank or ADSC-laden devices in rats. Following a 4 week implantation, the ADSC-laden devices were better vascularized and induced significantly less fibrotic tissue formation in comparison to the non-cellular controls. This study may facilitate our understanding of foreign-body responses and suggest new ways to improve the tissue reaction of biomedical devices for cell-based therapy.
Asunto(s)
Tejido Adiposo/citología , Materiales Biocompatibles/farmacología , Ensayo de Materiales/instrumentación , Células Madre Mesenquimatosas/citología , Neovascularización Fisiológica/efectos de los fármacos , Comunicación Paracrina/efectos de los fármacos , Animales , Antiinflamatorios/farmacología , Células Inmovilizadas/citología , Células Inmovilizadas/efectos de los fármacos , Técnicas de Cocultivo , Medios de Cultivo Condicionados/farmacología , Fibrosis , Regulación de la Expresión Génica/efectos de los fármacos , Imagenología Tridimensional , Implantes Experimentales , Masculino , Células Madre Mesenquimatosas/efectos de los fármacos , Neovascularización Fisiológica/genética , Ratas Sprague-Dawley , Esferoides Celulares/citología , Esferoides Celulares/efectos de los fármacosRESUMEN
By presenting biomolecular ligands on the surface in high density, ligand-decorated dendrimers are capable of binding to membrane receptors and cells with specificity and avidity. Despite the various uses, fundamental investigations on ligand-dendrimer conjugates have mainly focused on their binding behavior with cells, whereas their potential bioactivity and applications in multicellular systems, especially in three-dimensional (3D) culture systems, remains untapped. In this study, a typical adhesive peptide ligand - RGD - was modified to generation 4 polyamidoamine (PAMAM), and the bioactivity of suspended RGD-PAMAM conjugates was investigated on cells cultured as multicellular spheroids. Our results demonstrate that the RGD-PAMAM conjugates, after being incorporated into the 3D spheroids, were able to promote cellular proliferation and aggregation, and affect the mRNA expression of extracellular factors by NIH 3T3 cells. These bioactive functions were multivalency-dependent, as none of similar effects was observed for monovalent RGD ligand. Our study suggests that multivalent ligand-dendrimer conjugates may act as a unique type of artificial factors to mediate the cellular microenvironment in 3D culture, a property attributable to the spatial organization of the ligands and possible "cell-gluing" function of multivalent conjugates. This new finding opens the door for further exploring multivalent ligand-dendrimer conjugates for applications in 3D cell culture and tissue engineering.