Prevention of acute graft-versus-host disease by magnetic nanoparticles of Fe₃O₄ combined with cyclosporin A in murine models

Unlocking Transplant Tolerance with Biomaterials

For patients suffering from organ failure due to injury or autoimmune disease, allogeneic organ transplantation with chronic immunosuppression is considered the god standard in terms of clinical treatment. However, the true "holy grail" of transplant immunology is operational tolerance, in which the recipient exhibits a sustained lack of alloreactivity toward unencountered antigen presented by the donor graft. This outcome is resultant from critical changes to the phenotype and genotype of the immune repertoire predicated by the activation of specific signaling pathways responsive to soluble and mechanosensitive cues. Biomaterials have emerged as a medium for interfacing with and reprogramming these endogenous pathways toward tolerance in precise, minimally invasive, and spatiotemporally defined manners. By viewing seminal and contemporary breakthroughs in transplant tolerance induction through the lens of biomaterials-mediated immunomodulation strategies-which include intrinsic material immunogenicity, the depot effect, graft coatings, induction and delivery of tolerogenic immune cells, biomimicry of tolerogenic immune cells, and in situ reprogramming-this review emphasizes the stunning diversity of approaches in the field and spotlights exciting future directions for research to come.

Nanotechnology Applications in Transplantation Medicine

A recent technological advance that shows promise for applications in health care, including transplantation medicine, is the implementation of nanoparticles. Nanoparticles can be composed of a variety of organic or inorganic materials and confer many advantages over conventional treatments available, such as low toxicity, low-effective dosage required, and a high degree of manipulability. Although also used for imaging and diagnostics, nanoparticles' utility as a drug or genetic delivery system is of particular interest in transplantation medicine. Currently, researchers are exploring options to integrate nanoparticles into both diagnostics and therapy for both grafts ex-situ before transplantation and for patients following transplantation. These studies have demonstrated that nanoparticles can mitigate damage to organs and patients through a large variety of mechanisms-ranging from the induction of cellular genetic changes to the enhancement of immunosuppressive drug delivery. Specifically, with the advent of machine perfusion preservation ex vivo, treatment of the graft became a very attractive approach and nanoparticles have great potential. However, before nanoparticles can be translated into clinical use, their short-term and long-term toxicity must be thoroughly characterized, especially with regards to their interactions with other biological molecules present in the human body.

Glucocorticoids delivered by inorganic-organic hybrid nanoparticles mitigate acute graft-versus-host disease and sustain graft-versus-leukemia activity

Glucocorticoids (GCs) are widely used to treat acute graft-versus-host disease (aGvHD) due to their immunosuppressive activity, but they also reduce the beneficial graft-versus-leukemia (GvL) effect of the allogeneic T cells contained in the graft. Here, we tested whether aGvHD therapy could be improved by delivering GCs with the help of inorganic-organic hybrid nanoparticles (IOH-NPs) that preferentially target myeloid cells. IOH-NPs containing the GC betamethasone (BMP-NPs) efficiently reduced morbidity, mortality, and tissue damage in a totally MHC mismatched mouse model of aGvHD. Therapeutic activity was lost in mice lacking the GC receptor (GR) in myeloid cells, confirming the cell type specificity of our approach. BMP-NPs had no relevant systemic activity but suppressed cytokine and chemokine gene expression locally in the small intestine, which presumably explains their mode of action. Most importantly, BMP-NPs delayed the development of an adoptively transferred B cell lymphoma better than the free drug, although the overall incidence was unaffected. Our findings thus suggest that employing IOH-NPs could diminish the risk of relapse associated with GC therapy of aGvHD patients while still allowing to efficiently ameliorate the disease.

CXCR3 blockade combined with cyclosporine A alleviates acute graft-versus-host disease by inhibiting alloreactive donor T cell responses in a murine model

Chemotaxis of T cells to acute graft-versus-host disease (aGvHD) target tissues directed by chemokines and their receptors plays a key role in the pathogenesis of aGvHD. Blockade of lymphocyte migration by targeting chemokine receptors may be a viable strategy for the prevention and treatment of aGvHD, which is quite distinguishable from typical efforts to use immunosuppressive medications that have been associated with some side effects. CXCR3 and its ligands have been reported to be correlated with aGvHD pathogenesis. Using the small-molecule CXCR3 antagonist AMG487, we demonstrated that AMG487 combined with cyclosporine A (CsA) effectively alleviated aGvHD with a prolonged mean survival time and significantly inhibited the infiltration of inflammatory cells in aGvHD target tissues in a murine aGvHD model. In addition, AMG487 combined with CsA inhibited the activation, proliferation and differentiation of donor-derived T cells in the spleens. Further results showed that the concentrations of Th1 cells associated with pro-inflammatory cytokines such as IFN-γ and TNFα in serum were decreased. In addition, AMG487 treatment did not alter CXCR3 and CCR5 expression in donor-derived T cells but elevated the serum CXCL9 and CXCL10 levels. This novel and effective approach has the potential to develop a new clinical method to prevent and treat aGvHD.

Nanotechnology in the treatment of inflammatory bowel diseases

BACKGROUND AND AIMS

Treatment of inflammatory bowel diseases (IBD) is only aimed to block or inhibit the pathogenetic steps of the inflammatory cascade. Side effects of systemic therapies, poor targeting of orally administered topical drug and low adherence to prescription represent frequent therapeutic challenges. Recent observations suggest that nanotechnology could provide amazing advantage in this field since particles having dimension in the nanometer scale (nanoparticles) can modify pharmacokinetic step of biologic and conventional therapeutic agents with a better delivery of drugs within the intestinal inflammatory cells. The aim of this review was to provide the clinician with an insight into the potential role of nanotechnology in the treatment of IBD.

METHODS

A systematic search (PubMed) for experimental studies on the treatment of intestinal inflammation using nanotechnology for the delivery of drugs.

RESULTS AND CONCLUSIONS

The size of the pharmaceutical formulation is inversely related to specificity for inflammation. Nanoparticles can penetrate epithelial and inflammatory cells resulting in much higher, effective and long-acting concentrations than can be obtained using conventional delivery systems. From a practical point of view, this should lead to improvements in both efficacy and adherence to treatment, providing patients with the prospect of stable and prolonged remissions with reduced drug loadings. Reduced systemic side effects could also be expected.

Exercise benefits in chronic graft versus host disease: a murine model study

INTRODUCTION

Chronic graft versus host disease (cGVHD) is a life-threatening complication of allogeneic hematopoietic stem cell transplantation that generates considerable morbidity and compromises the physical capacity of patients. We determined the effects of an exercise training program performed after allogeneic hematopoietic stem cell transplantation on clinical and biological variables in a minor histocompatibility antigen-driven murine model of cGVHD treated with cyclosporine A.

METHODS

Recipient BALB/C female mice (age 8 wk) received bone marrow cells and splenocytes from donor B10.D2 male mice and were randomly assigned to an exercise (n = 11) or control group (n = 12). For approximately 11 wk after transplant, the exercise group completed a moderate-intensity treadmill program. Variables assessed were clinical severity scores, survival, physical fitness, cytokine profile, immune cell reconstitution, molecular markers of muscle exercise adaptations, and histological scores in affected tissues.

RESULTS

Exercise training increased survival (P = 0.011), diminished total clinical severity scores (P = 0.002), improved physical fitness (P = 0.030), and reduced blood IL-4 and tumor necrosis factor α levels (P = 0.03), while increasing circulating B220 (P = 0.008) and CD4 lymphocytes (P = 0.043).

CONCLUSIONS

A moderate-intensity exercise program that mimics widely accepted public health recommendations for physical activity in human adults was well tolerated and positive effects on survival as well as on clinical and biological indicators of cGVHD.