Intra-arterial catheter guided steroid administration for the treatment of steroid-refractory intestinal GvHD

Application of "Primed" Mesenchymal Stromal Cells in Hematopoietic Stem Cell Transplantation: Current Status and Future Prospects

Regenerative potential of mesenchymal stem/stromal cells (MSCs) has led to their application in various cellular therapies. Since in vivo these cells are present in very low numbers, they need expansion in culture to get clinically relevant numbers; however, such long-term ex vivo manipulation leads to loss of their regenerative capacity. Although use of naïve MSCs is still the most common approach used in various therapies, several strategies, both genetic and pharmacological, are being tried out to boost the regenerative capacity of in vitro expanded MSCs. Such manipulations are very commonly reported for regeneration of various tissues like bone, cartilage, kidney, pancreas, and others. Likewise, several efforts have been made to investigate priming of MSCs to enhance their immunoregulatory activity, but such efforts have not been made to the same extent for enhancing the efficacy of hematopoietic stem cell transplantation (HSCT). Development of such approaches for HSCT would not only be useful for enhancing the transplantation efficacy of cord blood cells, which are fewer in numbers, and aged HSCs, which could be functionally compromised, but also for genetically modified HSCs, which are likely to be both, fewer in number and functionally compromised. This review specifically deals with application of "primed" MSCs in the scenario of HSCT.

Enhanced Immunosuppressive Properties of Human Mesenchymal Stem Cells Primed by Interferon-γ

Mesenchymal stem cells (MSCs) are of particular interest for the treatment of immune-related diseases owing to their immunosuppressive properties. In this study, we aimed to identify the effect of interferon (IFN)-γ priming on immunomodulation by MSCs and elucidate the possible mechanism underlying their properties for the clinical treatment of allogeneic conflicts. Infusion of MSCs primed with IFN-γ significantly reduced the symptoms of graft-versus-host disease (GVHD) in NOD-SCID mice, thereby increasing survival rate when compared with naïve MSC-infused mice. However, infusion of IFN-γ-primed MSCs in which indoleamine 2,3-dioxygenase (IDO) was downregulated did not elicit this effect. The IDO gene was expressed in MSCs via the IFN-γ-Janus kinase (JAK)-signal transducer and activator of transcription 1 (STAT1) pathway, and the infusion of IDO-over-expressing MSCs increased survival rate in an in vivo GVHD model, similar to infusion of IFN-γ-primed MSCs. These data indicate that IFN-γ production by activated T-cells is correlated with the induction of IDO expression in MSCs via the IFN-γ-JAK-STAT1 pathway, which in turn results in the suppression of T-cell proliferation. Our findings also suggest that cell therapy based on MSCs primed with IFN-γ can be used for the clinical treatment of allogeneic conflicts, including GVHD.

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IFN-γ priming enhances the immunosuppressive properties of human MSCs in in vitro and in vivo models.

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IFN-γ priming induces IDO expression in MSCs via the JAK/STAT1 signaling pathway, but TLR3 activation does not.

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Cell therapy using MSCs primed with IFN-γ could be highly effective in treating allogeneic diseases, including GVHD.

It is necessary to improve the function of mesenchymal stem cells (MSCs) to maximize their treatment potential beyond what is currently achieved in cell therapy studies using naïve heterogeneous MSCs. The preclinical study of a candidate cell therapy based on MSCs primed with interferon-γ as reported in this study, could lay the foundation for the use of cell therapy for the treatment of graft-versus-host disease (GVHD), and is very important for the initiation of clinical trials. Our findings also suggest that cell therapy based on functionally improved MSCs could be used for the clinical treatment of allogeneic conflicts.

Regional intra-arterial steroid treatment in 120 patients with steroid-resistant or -dependent GvHD

GvHD results in death in the majority of steroid-resistant patients. This report assesses the safety and efficacy of two regional intra-arterial steroid (IAS) treatment protocols in the largest published cohort of patients with resistant/dependent hepatic and/or gastrointestinal GvHD, as well as identification of predictors of response to IAS and survival. One hundred and twenty patients with hepatic, gastrointestinal GvHD or both were given IAS. Gastrointestinal initial response (IR) and complete response (CR) were documented in 67.9% and 47.6%, respectively, whereas hepatic IR/CR in 54.9% and 33.3%, respectively. The predictors of gastrointestinal CR were lower peak GvHD and steroid-dependent (SD) GvHD. The predictors for hepatic CR were male patient, reduced intensity conditioning and SD GvHD. Twenty-six of the 120 patients (21.6%) are currently alive (median follow-up for the survivors 91.5 months). The 12 months' overall survival is 30% with no treatment-associated deaths. Predictors of 12 months' survival were as follows: first transplant, age<20 years, non-TBI regimen and GvHD CR. Shorter time to gastrointestinal IR but not time to hepatic IR was associated with improved 12 months' survival. IAS appears to be safe and effective. Gastrointestinal treatment is more effective than hepatic treatment. In our study, we conclude our current recommendations for IAS treatment.

Therapeutic targets and emerging treatment options in gastrointestinal acute graft-versus-host disease

Introduction

Graft-versus-host disease (GVHD) continues to be the major lethal complication of allogeneic hematopoietic stem cell transplantation (HCT) but the standard of care, high dose steroids, has not changed in 40 years. Approximately 50% of GVHD patients will develop steroid refractory disease, typically involving the gastrointestinal (GI) tract, which has a very poor prognosis. Newly developed GVHD biomarker-based risk scores provide the first opportunity to treat patients at the onset of symptoms according to risk of steroid failure. Furthermore, improvements in our understanding of the pathobiology of GVHD, its different signaling pathways, involved cytokines, and the role of post-translational and epigenetic modifications, has identified new therapeutic targets for clinical trials.

Areas covered

This manuscript summarizes the pathophysiology, diagnosis, staging, current and new targeted therapies for GVHD, with an emphasis on GI GVHD. A literature search on PubMed was undertaken and the most relevant references included.

Expert Opinion

The standard treatment for GVHD, high dose steroids, offers less than optimal outcomes as well as significant toxicities. Better treatments, especially for GI GVHD, are needed to reduce non-relapse mortality after allogeneic HCT. The identification of high risk patients through a biomarker-defined scoring system offers a personalized approach to a disease that still requires significant research attention.

Intra-Arterial Platelet Infusion for Intractable Hemorrhage and Refractory Thrombocytopenia in Children With Gastrointestinal Graft-Versus-Host Disease

Acute gastrointestinal graft-versus-host disease (GVHD) refractory to first-line treatment with systemic corticosteroids results in increased morbidity and potential mortality. We retrospectively assessed the feasibility and efficacy of catheter-directed intra-arterial platelet infusion (IAPI) in two pediatric patients with steroid and transfusion refractory gastrointestinal GVHD causing intractable lower gastrointestinal hemorrhage and refractory thrombocytopenia, that were referred for salvage therapy. Immediate angiographic response was noted with a resolution of hemorrhage and decreased blood requirements. We reviewed the literature regarding this treatment modality and compared it to the available minimally invasive transcatheter techniques to control gastrointestinal hemorrhage.

Efficacy and safety of intra-arterial steroid infusions in patients with steroid-resistant gastrointestinal acute graft-versus-host disease

There is no established second-line treatment for steroid-resistant acute graft-versus-host disease (GVHD). We prospectively assessed the safety and efficacy of intra-arterial steroid infusions (IASIs) for steroid-resistant acute gastrointestinal (GI) GVHD and compared the outcomes with those of historical controls at our institution. Nineteen consecutive, allogeneic hematopoietic stem cell transplantation subjects aged 31-67 years (median 52) were enrolled between October, 2008, and November, 2012. Acute GVHD was confirmed by biopsy in all cases. The enrolled patients were treated with infusions of methylprednisolone into the mesenteric arteries and/or gastroduodenal and left gastric arteries. Fourteen consecutive patients who developed steroid-resistant acute GI GVHD between 2001 and 2008 were used as controls. For the primary endpoint at day 28, the overall and complete responses in the IASI group trended higher (79% vs. 42%, p = 0.066) and were significantly higher (63% vs. 21%, p = 0.033) than those in the control group. Although not statistically significant, owing to the small population, the crude day-180-nonrelapse mortality rate was about 20% lower and the day-180-overall-survival rate tended to be higher than the control (11% vs. 29%, p = 0.222; 79% vs. 50%, p = 0.109, respectively). There were no serious IASI-related complications. Our results suggest that IASI can safely provide excellent efficacy for refractory acute GI GVHD without increasing infection-related complications and may improve prognosis.

Possible implication of bacterial infection in acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

Graft-versus-host disease (GVHD) is still one of the major causes of morbidity and mortality in allogeneic hematopoietic stem cell transplantation (HSCT). In the pathogenesis of acute GVHD, it has been established that donor-derived T-cells activated in the recipient play a major role in GVHD in initiation and maintenance within an inflammatory cascade. To reduce the risk of GVHD, intensification of GVHD prophylaxis like T-cell depletion is effective, but it inevitably increases the risk of infectious diseases and abrogates beneficial graft-versus-leukemia effects. Although various cytokines are considered to play an important role in the pathogenesis of GVHD, GVHD initiation is such a complex process that cannot be prevented by means of single inflammatory cytokine inhibition. Thus, efficient methods to control the whole inflammatory milieu both on cellular and humoral view are needed. In this context, infectious diseases can theoretically contribute to an elevation of inflammatory cytokines after allogeneic HSCT and activation of various subtypes of immune effector cells, which might in summary lead to an aggravation of acute GVHD. The appropriate treatments or prophylaxis of bacterial infection during the early phase after allogeneic HSCT might be beneficial to reduce not only infectious-related but also GVHD-related mortality. Here, we aim to review the literature addressing the interactions of bacterial infections and GVHD after allogeneic HSCT.