Chitosan/γ-PGA nanoparticles-based immunotherapy as adjuvant to radiotherapy in breast cancer.

Radiotherapy (RT) is an essential treatment modality for several types of cancer. Despite its therapeutic potential, RT is frequently insufficient to overcome the immunosuppressive nature of the tumor microenvironment, failing to control tumor metastases. Innovative immunomodulatory strategies, like immunostimulatory biomaterials could be used to boost the immunogenic effects of RT. Herein, we addressed the synergistic potential of immunostimulatory chitosan/poly(γ-glutamic acid) nanoparticles (Ch/γ-PGA NPs) combined with RT to induce antitumor immunity in the 4T1 orthotopic breast tumor mouse model. Non-treated animals had progressive primary tumor growth and developed splenomegaly and lung metastases. While RT decreased primary tumor burden, Ch/γ-PGA NPs-treatment decreased systemic immunosuppression and lung metastases. The combination therapy (RT + Ch/γ-PGA NPs) synergistically impaired 4T1 tumor progression, which was associated with a significant primary tumor growth and splenomegaly reduction, a decrease in the percentage of splenic immunosuppressive myeloid cells and an increase in antitumoral CD4+IFN-γ+ population. Notably, animals from the combination therapy presented less and smaller lung metastatic foci and lower levels of the systemic pro-tumor cytokines IL-3, IL-4, IL-10, and of the CCL4 chemokine, in comparison to non-treated animals. Overall, these results evidenced that Ch/γ-PGA NPs potentiate and synergize with RT, headlining their promising role as adjuvant anticancer strategies.

Chitosan/poly(γ-glutamic acid) nanoparticles incorporating IFN-γ for immune response modulation in the context of colorectal cancer.

IFN-γ therapy has been approved by the Food and Drug Administration (FDA) for the treatment of chronic granulomatous disease and severe malignant osteopetrosis. Despite the promising IFN-γ-based therapeutic applications, its limited success in clinical trials is related with limitations inherent to its molecular properties and with the difficulties to deliver it locally or with adequate periodicity to achieve a therapeutic effect. We have previously shown that chitosan (Ch)/poly(γ-glutamic acid) (γ-PGA) nanoparticles (NPs) are immunostimulatory, impairing colorectal cancer cell invasion. Ch is a biocompatible cationic polysaccharide extensively studied and already approved for biomedical applications while γ-PGA is a poly(amino acid), biodegradable and negatively charged. Here, we evaluated the potential of Ch/γ-PGA NPs as vehicles for IFN-γ and their ability to modulate immune cells' phenotype. In this study, Ch/IFN-γ/γ-PGA nanoparticles (IFN-γ-NPs) prepared by a co-acervation method, presenting a size of approximately 180 nm and a low polydispersity index, were tested for their immunomodulatory activity. These IFN-γ-NPs induced an immunostimulatory profile on dendritic cells (DCs) with increased cell surface costimulatory molecules and secretion of pro-inflammatory cytokines, including IL-6, IL-12p40 and TNF-α. IFN-γ-NPs also modulated the IL-10-stimulated macrophage profile, increasing their ability to secrete the pro-inflammatory cytokines IL-6, IL-12p40 and TNF-α. Concomitantly, these phenotypic alterations enhanced T cell proliferation. In addition, the ability of DCs and macrophages to induce colorectal cancer cell invasion was hampered in the presence of IFN-γ-NPs. Although the major observations were mediated by Ch/γ-PGA NPs, the incorporation of IFN-γ into NPs potentiated the expression of CD40 and CD86, and the impairment of colorectal cancer cell invasion. This work bridges the previously reported immunostimulatory capacity of Ch/γ-PGA NPs with their potential as carriers for immunomodulatory molecules, like IFN-γ, opening new avenues for their use in clinical settings.

Pro-inflammatory chitosan/poly(γ-glutamic acid) nanoparticles modulate human antigen-presenting cells phenotype and revert their pro-invasive capacity.

Anticancer immune responses depend on efficient presentation of tumor antigens and co-stimulatory signals provided by antigen-presenting cells (APCs). However, it is described that immature dendritic cells (DCs) and macrophages at the tumor site may have an immunosuppressive profile, which limits the activity of effector T cells and supports tumor progression. Therapeutic targeting of these innate immune cells, either aiming at their elimination or re-polarization towards an immunostimulatory profile, has been pointed as an attractive approach to control tumor progression. In the present work, we assessed the potential of Chitosan (Ch)/Poly(γ-glutamic acid) (γ-PGA) nanoparticles (NPs) to modulate macrophages and DCs inflammatory profile and to impair their ability to promote cancer cell invasion. Interestingly, Ch/γ-PGA NPs, prepared by co-acervation method, induced an immunostimulatory DCs phenotype, enhancing the expression of the co-stimulatory molecules CD86, CD40 and HLA-DR, and the secretion of the pro-inflammatory cytokines TNF-α, IL-12p40 and IL-6. Furthermore, Ch/γ-PGA NPs re-educated IL-10-stimulated macrophages towards a pro-inflammatory profile, decreasing the expression of CD163 and promoting the secretion of IL-12p40 and TNF-α. These alterations in the immune cells phenotype promoted CD4+ and CD8+ T cell activation/proliferation and partially inhibited APCs' ability to induce colorectal cancer cell invasion. Overall, our findings open new perspectives on the use of Ch/γ-PGA NPs as an immunomodulatory therapy for antigen-presenting cells reprogramming, providing a new tool for anticancer therapies. STATEMENT OF SIGNIFICANCE: The immune system is responsible to detect and destroy abnormal cells preventing the development of cancer. However, the immunosuppressive tumor microenvironment can compromise the immune response favoring tumor progression. Thus, immune system modulation towards an immunostimulatory profile can improve anticancer therapies. This research focus on the development of chitosan/poly(γ-glutamic acid) nanoparticles (NPs) to modulate human antigen-presenting cells (APCs) phenotype and to counteract their pro-invasive capacity. Interestingly, Ch/γ-PGA NPs had a prominent effect in inducing macrophages and dendritic cells immunostimulatory phenotype, thus favoring T cell proliferation and inhibiting colorectal cancer cell invasion. We propose that their combination with other immunomodulatory drugs or conventional anticancer therapies can improve patients' outcome.

Systemic Delivery of Bone Marrow Mesenchymal Stem Cells for In Situ Intervertebral Disc Regeneration.

Cell therapies for intervertebral disc (IVD) regeneration presently rely on transplantation of IVD cells or stem cells directly to the lesion site. Still, the harsh IVD environment, with low irrigation and high mechanical stress, challenges cell administration and survival. In this study, we addressed systemic transplantation of allogeneic bone marrow mesenchymal stem cells (MSCs) intravenously into a rat IVD lesion model, exploring tissue regeneration via cell signaling to the lesion site. MSC transplantation was performed 24 hours after injury, in parallel with dermal fibroblasts as a control; 2 weeks after transplantation, animals were killed. Disc height index and histological grading score indicated less degeneration for the MSC-transplanted group, with no significant changes in extracellular matrix composition. Remarkably, MSC transplantation resulted in local downregulation of the hypoxia responsive GLUT-1 and in significantly less herniation, with higher amounts of Pax5+ B lymphocytes and no alterations in CD68+ macrophages within the hernia. The systemic immune response was analyzed in the blood, draining lymph nodes, and spleen by flow cytometry and in the plasma by cytokine array. Results suggest an immunoregulatory effect in the MSC-transplanted animals compared with control groups, with an increase in MHC class II+ and CD4+ cells, and also upregulation of the cytokines IL-2, IL-4, IL-6, and IL-10, and downregulation of the cytokines IL-13 and TNF-α. Overall, our results indicate a beneficial effect of systemically transplanted MSCs on in situ IVD regeneration and highlight the complex interplay between stromal cells and cells of the immune system in achieving successful tissue regeneration. Stem Cells Translational Medicine 2017;6:1029-1039.

Role of physical activity in the occurrence of falls and fall-related injuries in community-dwelling adults over 50 years old.

PURPOSE: This study examined the effect of the type, level and amount of physical activity in falls and fall-related injuries. METHOD: Participants were 506 community-dwelling adults aged >50 years (390 women: 67.7 ± 6.8 years and 116 men: 69.6 ± 6.6 years). Falls, fall-related injuries (slight and severe), and physical activity (type, level and energy expenditure) were evaluated by questionnaires. Confounders included co-morbidities, fear of falling, environmental hazards and physical fitness. RESULTS: After adjustment for confounders, logistic analysis revealed that the likelihood of falling decreased by 2% for each 100 metabolic expenditure (MET-min/week) of total physical activity and increased by 5% for each 100 MET-min/week of vigorous-intensity physical activity; total physical activity >1125 MET-min/week and vigorous physical activity <500 MET-min/week were identified as cut-off values discriminating non-fallers from fallers. Compared to the low physical activity level, increased physical activity levels diminished the likelihood of the occurrence of severe fall-related injuries by 76% (moderate) and 58% (high; p < 0.05) in fallers. CONCLUSIONS: Being active, especially sufficiently active, reduces fall-related injuries by decreasing falls and by safeguarding against severe injuries when falls occur. At least 1125 MET-min/week of total physical activity including >500 MET-min/week of vigorous intensity seems to prevent falls and, therefore, fall-related injuries.

Men older than 50 yrs are more likely to fall than women under similar conditions of health, body composition, and balance.

OBJECTIVE: The aim of this study was to analyze the contribution of sex to the occurrence of falls, accounting for comorbidities and differences in physical fitness. DESIGN: This was a cross-sectional study of 587 community-dwelling adults who were older than 50 yrs. Falls, comorbidities (number of diseases and physical impairments), and physical fitness (body composition, lower and upper body strength and flexibility, agility, aerobic endurance, and balance) were evaluated via questionnaires, bioimpedance, and Fullerton batteries, respectively. RESULTS: Compared with the men, the women presented a 10% higher fall prevalence, 1.7 more diseases/impairments, 10% more body fat, 26% less lean body mass, and poorer physical capacity (P < 0.05). Multivariate logistic regression revealed that male sex (odds ratio [OR], 2.723; 95% confidence interval [CI], 1.190-6.230) increased the likelihood of falling, after adjustment for comorbidities (OR, 1.213; 95% CI, 1.109-1.328), lean mass (OR, 0.958; 95% CI, 0.927-0.989), fat mass (OR, 1.053; 95% CI, 1.021-1.086), and balance (OR, 0.942; 95% CI, 0.914-0.971), which were the main risk factors of falls. CONCLUSIONS: Women are more susceptible to falling, presumably because they have poorer health and physical fitness than do men. However, when the values for comorbidities, lean and fat body mass, and balance were similar, the men demonstrated a higher probability of falling. Age is not a significant risk factor of falls under favorable conditions of health, body composition, and balance.