Immunosuppressive Therapy in Transplantation

Continuous immunosuppression is required for suppressing immune responses to xenografts in non-human primate brains

Continuous immunosuppression has been widely used in xenografts into non-human primate brains. However, how immune responses change after transplantation in host brains under continuous immunosuppressive administration and whether immunosuppression can be withdrawn to mitigate side effects remain unclear. Human induced neural stem/progenitor cells (iNPCs) have shown long-term survival and efficient neuronal differentiation in primate brains. Here, we evaluate the immune responses in primate brains triggered by human grafts. The results show that the immune responses, including the evident activation of microglia and the strong infiltration of lymphocytes (both T- and B-cells), are caused by xenografts at 4 months post transplantation (p.t.), but significantly reduced at 8 months p.t. under continuous administration of immunosuppressant Cyclosporin A. However, early immunosuppressant withdrawal at 5 months p.t. results in severe immune responses at 10 months p.t. These results suggest that continuous long-term immunosuppression is required for suppressing immune responses to xenografts in primate brains.

Immunolocalization of Matrix Metalloproteinases 2 and 9 and Their Inhibitors in the Hearts of Rats Treated with Immunosuppressive Drugs-An Artificial Intelligence-Based Digital Analysis

BACKGROUND

Immunosuppressive agents represent a broad group of drugs, such as calcineurin inhibitors, mTOR inhibitors, and glucocorticosteroids, among others. These drugs are widely used in a number of conditions, but lifelong therapy is crucial in the case of organ recipients to prevent rejection. To further increase the safety and efficacy of these agents, their off-target mechanisms of action, as well as processes underlying the pathogenesis of adverse effects, need to be thoroughly investigated. The aim of this study was to examine the impact of various combinations of cyclosporine/tacrolimus/mycophenolate with rapamycin and steroids (CRG, TRG, MRG), on the morphology and morphometry of rats' cardiomyocytes, together with the presence of cardiac collagen and the immunoexpression of MMPs and TIMPs.

METHODS

Twenty-four rats were divided into four groups receiving different immunosuppressive regiments. After six months of treatment, the hearts were collected and analyzed.

RESULTS

Cardiomyocytes from the CRG cohorts demonstrated the most pronounced morphological alterations. In addition, chronic immunosuppression reduced the width and length of cardiac cells. However, immunosuppressive therapy did not alter the presence of cardiac collagen fibers. Nevertheless, we observed significant alterations regarding MMP/TIMP homeostasis.

CONCLUSIONS

Chronic immunosuppression seems to disturb the MMP/TIMP balance in aspects of immunolocalization in the hearts of rats. Further studies are required to analyze other mechanisms and pathways affected by the use of immunosuppressants.

Effect of rapamycin on Cryptococcus neoformans: cellular organization, biophysics and virulence factors

Background: Cryptococcus neoformans is an opportunistic fungal pathogen that causes infections mainly in immunosuppressed individuals, such as transplant recipients. Aims: This study investigated the effects of rapamycin, an immunosuppressant drug, on the cellular organization, biophysical characteristics, and main virulence factors of C. neoformans. Methods: Morphological, structural, physicochemical and biophysical analyses of cells and secreted polysaccharides of the reference H99 C. neoformans strain were investigated under the effect of subinhibitory concentrations of rapamycin. Results: Rapamycin at a minimum inhibitory concentration of 2.5 μM reduced C. neoformans cell viability by 53%, decreased capsule, increased cell size, chitin and lipid body formation, and changed peptidase and urease activity. Conclusion: Further studies are needed to assess how rapamycin affects the virulence factors and pathogenicity of C. neoformans.

Malignant Melanoma in a Retrospective Cohort of Immunocompromised Patients: A Statistical and Pathologic Analysis

BACKGROUND

Malignant melanoma is the leading cause of death due to cutaneous malignancy. Immunocompromised individuals have an elevated risk of developing melanoma. We aimed to provide histopathologic and statistical characterization of melanoma development in immunocompromised patients.

METHODS

We reviewed our institution's databases to identify all patients with a confirmed history of immunosuppression who subsequently developed melanoma, focusing on diagnoses during the follow-up period of 2011-2019. A total of 93 patients with a combined 111 melanoma lesions were identified.

RESULTS

Common causes of immunosuppression included transplantation and lymphoproliferative disorders. Superficial spreading and lentigo malignant melanoma were the most common malignant melanoma subtypes. Median Breslow depth was 0.7 mm, and the most common primary tumor stage was T1a. Our transplant sub-cohort had an overall melanoma incidence of 0.9 per 1000 person-years (95% CI 0.66 to 1.20) and a standardized incidence ratio (SIR) of 1.53 (95% CI 1.12 to 2.04) relative to a general population cohort from the Surveillance, Epidemiology, and End Results Program (SEER).

CONCLUSIONS

We report histopathologic characteristics of immunocompromised patients developing melanoma at a large academic tertiary-care center. Differences in age, sex, time since transplantation, and transplant type may play a significant role in melanoma SIR in this patient demographic.

Decellularized Extracellular Matrix: The Role of This Complex Biomaterial in Regeneration

Organ transplantation is understood as a technique where an organ from a donor patient is transferred to a recipient patient. This practice gained strength in the 20th century and ensured advances in areas of knowledge such as immunology and tissue engineering. The main problems that comprise the practice of transplants involve the demand for viable organs and immunological aspects related to organ rejection. In this review, we address advances in tissue engineering for reversing the current challenges of transplants, focusing on the possible use of decellularized tissues in tissue engineering. We address the interaction of acellular tissues with immune cells, especially macrophages and stem cells, due to their potential use in regenerative medicine. Our goal is to exhibit data that demonstrate the use of decellularized tissues as alternative biomaterials that can be applied clinically as partial or complete organ substitutes.

Infections after organ transplantation and immune response

Organ transplantation has provided another chance of survival for end-stage organ failure patients. Yet, transplant rejection is still a main challenging factor. Immunosuppressive drugs have been used to avoid rejection and suppress the immune response against allografts. Thus, immunosuppressants increase the risk of infection in immunocompromised organ transplant recipients. The infection risk reflects the relationship between the nature and severity of immunosuppression and infectious diseases. Furthermore, immunosuppressants show an immunological impact on the genetics of innate and adaptive immune responses. This effect usually reactivates the post-transplant infection in the donor and recipient tissues since T-cell activation has a substantial role in allograft rejection. Meanwhile, different infections have been found to activate the T-cells into CD₄⁺ helper T-cell subset and CD₈⁺ cytotoxic T-lymphocyte that affect the infection and the allograft. Therefore, the best management and preventive strategies of immunosuppression, antimicrobial prophylaxis, and intensive medical care are required for successful organ transplantation. This review addresses the activation of immune responses against different infections in immunocompromised individuals after organ transplantation.

Biological evaluation of acellular bovine bone matrix treated with NaOH

We mainly proceed from the view of biological effect to study the acellular bovine bone matrix (ABBM) by the low concentration of hydrogen oxidation. After cleaning the bovine bone routinely, it was cleaned with different concentrations of NaOH and stained with hematoxylin-eosin (HE) to observe the effect of decellulization. The effect of bovine bone matrix treated with NaOH were observed by optical microscopy and scanning electron microscopy (SEM), and compared by DNA residue detection. Cell toxicity was also evaluated in MC3T3-E1 cells by CCK-8. For the in vitro osteogenesis detection, alkaline phosphatase (ALP) staining and alizarin red (AR) staining were performed in MC3T3-E1 cells. And the in vivo experiment, Micro CT, HE and Masson staining were used to observe whether the osteogenic effect of the materials treated with 1% NaOH solution was affected at 6 and 12 weeks. After the bovine bone was decellularized with different concentrations of NaOH solution, HE staining showed that ultrasonic cleaning with 1% NaOH solution for 30 min had the best effect of decellularization. The SEM showed that ABBM treated with 1% NaOH solution had few residual cells on the surface of the three-dimensional porous compared to ABBM treated with conventional chemical reagents. DNA residues and cytotoxicity of ABBM treated with 1% NaOH were both reduced. The results of ALP staining and AR staining showed that ABBM treated with 1% NaOH solution had no effect on the osteogenesis effect. The results of micro-CT, HE staining and Masson staining in animal experiments also showed that ABBM treated with 1% NaOH solution had no effect on the osteogenesis ability. The decellularization treatment of ABBM with the low concentration of NaOH can be more cost-effective, effectively remove the residual cellular components, without affecting the osteogenic ability. Our work may provide a novelty thought and a modified method to applicate the acellular bovine bone matrix clinically better. Graphical abstract.

Pharmaceutical services based on therapeutic care pathway for kidney transplantation from donors of infants and young children: a single-center experience

BACKGROUND

The pharmaceutical services based on therapeutic care pathway for kidney transplantation from infants and young children (age <3 years, weight <15 kg) to pediatric recipients can detect and resolve medication-related problems. In this paper, we report our experience on pharmaceutical services based on therapeutic care pathway to evaluate the therapeutic effects and assess the feasibility of perioperative treatment protocols.

METHODS

We performed a retrospective study of 12 recipients who received their graft from infants and young children, between September 2011 and December 2013 at our institution. As providers of pharmaceutical services, the clinical pharmacists collected and reviewed the clinical data from all patients, including the clinical characteristics, outcome indices, and follow-up dates. A three-step-protocol of pharmaceutical services including clinician's application, pharmacist consultation, and ongoing direct pharmaceutical care and follow-up was used through the entire length of patient's admission, hospitalization, and discharge. This protocol was developed and refined based on the guidelines for transplant perioperative treatment and experiences of the clinical pharmacists to standardize the workflow, and improve the medical treatment and quality of life of patients.

RESULTS

There was no acute rejection, graft loss, or death in 10 recipients after transplantation, and another 2 received nephrectomy due to dysfunction. Postoperative follow-up of the patients who received the pharmaceutical services from the clinical pharmacist showed an effectiveness in managing medication-related complications, patient-related factors, and an improvement of the outcomes.

CONCLUSIONS

The three-step protocol of pharmaceutical services for pharmaceutical care and individual dosing regimen sponsored by pharmacists facilitated access to personalized therapies for children undergoing kidney transplantation in our hospital.

Modeling the Potential of Treg-Based Therapies for Transplant Rejection: Effect of Dose, Timing, and Accumulation Site

Introduction: The adoptive transfer of regulatory T cells (Tregs) has emerged as a method to promote graft tolerance. Clinical trials have demonstrated the safety of adoptive transfer and are now assessing their therapeutic efficacy. Strategies that generate large numbers of antigen specific Tregs are even more efficacious. However, the combinations of factors that influence the outcome of adoptive transfer are too numerous to be tested experimentally. Here, mathematical modeling is used to predict the most impactful treatment scenarios. Methods: We adapted our mathematical model of murine heart transplant rejection to simulate Treg adoptive transfer and to correlate therapeutic efficacy with Treg dose and timing, frequency of administration, and distribution of injected cells. Results: The model predicts that Tregs directly accumulating to the graft are more protective than Tregs localizing to draining lymph nodes. Inhibiting antigen-presenting cell maturation and effector functions at the graft site was more effective at modulating rejection than inhibition of T cell activation in lymphoid tissues. These complex dynamics define non-intuitive relationships between graft survival and timing and frequency of adoptive transfer. Conclusion: This work provides the framework for better understanding the impact of Treg adoptive transfer and will guide experimental design to improve interventions.

Hip Arthroplasty Outcomes for Femoral Neck Fractures in Transplant Patients

BACKGROUND

The purpose of this study was to compare the short-term complications between transplant and nontransplant patients who undergo hip arthroplasty for femoral neck fractures (FNFs). Additionally, we sought to further compare the outcomes of total hip arthroplasty (THA) versus hemiarthroplasty (HA) within the transplant group.

METHODS

This was a retrospective review utilizing the Nationwide Readmissions Database. Transplant patients were identified and stratified based on transplant type: kidney, liver, or other (heart, lung, bone marrow, and pancreas). Outcomes of interest included index hospitalization mortality, perioperative complications, length of stay, costs, hospital readmission, and surgical complications within 90 days of discharge.

RESULTS

From 2010 to 2018, a total of 881,061 patients underwent THA or HA for FNFs, of which 2163 (0.2%) were transplant patients. When compared with nontransplant patients, all transplant patients had an increased risk of requiring blood transfusion (odds ratio [OR] = 1.51, P = .001), acute kidney injury (OR = 2.02, P < .001), and discharge to facility (OR = 1.67, P = .001) while having increased index hospitalization length of stay and costs. Liver and other transplant patients had an increased risk of readmission within 90 days (OR = 1.82, P < .001 and OR = 1.60, P = .014 respectively). Subgroup analysis for transplant patients comparing HA with THA demonstrated no differences in perioperative complication rates and decreased hospitalization length of stay and cost associated with THA.

CONCLUSION

In this retrospective cohort study, transplant patients had an increased risk of requiring blood transfusions and acute kidney injury after hip arthroplasty for FNFs. There were no differences in short-term complications between transplant patients treated with HA versus THA.

LEVEL OF EVIDENCE

3 (Retrospective cohort study).

Typical and atypical properties of peripheral nerve allografts enable novel strategies to repair segmental-loss injuries

We review data showing that peripheral nerve injuries (PNIs) that involve the loss of a nerve segment are the most common type of traumatic injury to nervous systems. Segmental-loss PNIs have a poor prognosis compared to other injuries, especially when one or more mixed motor/sensory nerves are involved and are typically the major source of disability associated with extremities that have sustained other injuries. Relatively little progress has been made, since the treatment of segmental loss PNIs with cable autografts that are currently the gold standard for repair has slow and incomplete (often non-existent) functional recovery. Viable peripheral nerve allografts (PNAs) to repair segmental-loss PNIs have not been experimentally or clinically useful due to their immunological rejection, Wallerian degeneration (WD) of anucleate donor graft and distal host axons, and slow regeneration of host axons, leading to delayed re-innervation and producing atrophy or degeneration of distal target tissues. However, two significant advances have recently been made using viable PNAs to repair segmental-loss PNIs: (1) hydrogel release of Treg cells that reduce the immunological response and (2) PEG-fusion of donor PNAs that reduce the immune response, reduce and/or suppress much WD, immediately restore axonal conduction across the donor graft and re-innervate many target tissues, and restore much voluntary behavioral functions within weeks, sometimes to levels approaching that of uninjured nerves. We review the rather sparse cellular/biochemical data for rejection of conventional PNAs and their acceptance following Treg hydrogel and PEG-fusion of PNAs, as well as cellular and systemic data for their acceptance and remarkable behavioral recovery in the absence of tissue matching or immune suppression. We also review typical and atypical characteristics of PNAs compared with other types of tissue or organ allografts, problems and potential solutions for PNA use and storage, clinical implications and commercial availability of PNAs, and future possibilities for PNAs to repair segmental-loss PNIs.

Implantable Immunosuppressant Delivery to Prevent Rejection in Transplantation

An innovative immunosuppressant with a minimally invasive delivery system has emerged in the biomedical field. The application of biodegradable and biocompatible polymer forms, such as hydrogels, scaffolds, microspheres, and nanoparticles, in transplant recipients to control the release of immunosuppressants can minimize the risk of developing unfavorable conditions. In this review, we summarized several studies that have used implantable immunosuppressant delivery to release therapeutic agents to prolong allograft survival. We also compared their applications, efficacy, efficiency, and safety/side effects with conventional therapeutic-agent administration. Finally, challenges and the future prospective were discussed. Collectively, this review will help relevant readers understand the different approaches to prevent transplant rejection in a new era of therapeutic agent delivery.

Immunosuppression after uterus transplantation

PURPOSE OF REVIEW

Clinical uterus transplantation (UTx) is growing rapidly. The procedure represents the only therapy for women with absolute uterine factor infertility to give birth to a biological baby. Immunosuppression after UTx needs to carefully balance effects with the healthy mother and baby. Unique for UTx is the 'temporary' character of the procedure with a transplant hysterectomy being performed after delivery. Most of the practice on immunosuppression in UTx is currently based on the experience in solid organ transplantation (SOT).

RECENT FINDINGS

Clinical UTx-trials have been performed in centers worldwide during the recent years and experience on immunosuppression has accumulated.

SUMMARY

Immunosuppression in UTx has been successfully applied as maintenance treatment in addition to effectively treating acute T- and B-cell mediated rejections. Understanding the biology of UTx in more detail is expected to refine future approaches.

Biomimetic polyphenol-coated nanoparticles by Co-assembly of mTOR inhibitor and photosensitizer for synergistic chemo-photothermal therapy

Rapamycin (RAPA) functions as effectively clinical immunosuppressive agent, its significant tumor growth suppression effect via various pathways in diverse cancers, especially combined with photothermal therapy, is gaining a burgeoning attention. However, its critical defects, low solubility and poor stability, have severely hampered its further application. Herein, RAPA, indocyanine green (ICG) and epigallocatechin gallate (EGCG) serving as chemotherapeutic drug, photosensitizer and biomimetic coatings, respectively, were co-assembled into carrier-free, high biocompatible ICG-RAPA-EGCG nanoparticles (IRE NPs) for synergistic cancer therapy. Particularly, the bioinspired EGCG coatings not only improved the stability of IRE NPs under physiological conditions to avert NPs disassembly and drug release, but also maintained the photostability of ICG to achieve excellent photothermal response. The results indicated that the as-prepared IRE NPs displayed good monodispersity and enhanced stability at various stored media after introducing of EGCG. Compared with monotherapy of RAPA or ICG, IRE NPs showed higher dose-dependent toxicity in MCF-7 cells, HepG2 cells and HeLa cells, especially plus near-infrared laser irradiation. Furthermore, IRE NPs exhibited quicker uptake in cells, higher accumulation in tumor region (even in 48 h) than free ICG and effectively inhibited tumor growth without side effect in H22 tumor-bearing mice. Collectively, the carrier-free IRE NPs provided a simply alternative approach to fabricate RAPA/photosensitizer co-loaded nanoparticles for combinatorial tumor therapy.

Combination of matrine and tacrolimus alleviates acute rejection in murine heart transplantation by inhibiting DCs maturation through ROS/ERK/NF-κB pathway

Matrine, an alkaloid derived from traditional Chinese herbs, has been confirmed to regulate immunity and exert anti-inflammatory effects. Matrine injection has been widely used in clinic therapy for anti-tumor and anti-inflammatory diseases. Heart transplantation(HT) is the only solution for the end-stage heart failure, but it is restricted by the cardiac allograft rejection. One of the important pathophysiological processes of post-transplantation rejection is inflammatory cell infiltration. Matrine has been shown to exert a positive protective effect against oxidative stress injury and inflammation, which likely benefits allograft survival. However, it remains unclear whether matrine inhibits alloimmunity or allograft rejection. In this study, we established the heart transplantation model in mouse and extracted bone marrow-derived dendritic cells (BMDCs) to explore the function and mechanism of matrine in heart transplantation. Moreover, combination treatment with matrine and tacrolimus(FK506) had a synergistic effect in preventing acute rejection of heart transplants. Here we found that matrine can prolong the survival of post-transplant and inhibit inflammatory cell infiltration in transplanted hearts of mice. At the same time, matrine increased Treg ratio and decreased CD4+/CD8 + ratio in mice. More importantly, matrine inhibited DCs maturation in mice and reduced oxidative damage and apoptosis in allograft hearts. Furthermore, matrine also downregulated NF-κB pathway and upregulated ERK1/2 signaling pathway. Overall, our study reveals a novel immunosuppressive agent that has the potential to reduce the side effects of existing immunosuppressive agents when used in combination with them.

Oral diseases after liver transplantation: a systematic review and meta-analysis

Objective To conduct a systematic review and meta-analysis to evaluate the impact of liver transplantation on the occurrence and frequency of oral diseases in humans.Data sources The study query was performed on Medline/PubMed, Ovid, Cochrane Library and Embase databases, including the grey literature.Data selection Observational studies comparing the frequency of oral manifestations in post-liver transplantation patients versus reference population were eligible for inclusion.Data extraction and analysis The article selection, data extraction and quality assessment were executed by three independent investigators. A random-effects meta-analysis was carried out for computation of relative risks of oral malignancies (standardised incidence ratio [SIR] and 95% confidence interval [CI]).Data synthesis Among 248 studies identified, 11 met the eligibility criteria and six were included in the meta-analysis. Opportunistic fungal infections (Candida spp.) and lesions with malignant potential were reported to be more frequently prevalent after liver transplantation. Calculations indicated that after liver transplantation, the patients have a fivefold increased risk for oral cancer occurrence compared to the general population (SIR = 5.006; 95% CI 2.803 to 8.94; p <0.001).Conclusions The findings suggest that liver transplantation increases the risk of oral malignancies and the frequency of other mucosal lesions.

Targeting Inflammation and Oxidative Stress as a Therapy for Ischemic Kidney Injury

Inflammation and oxidative stress are the main pathological processes that accompany ischemic injury of kidneys and other organs. Based on this, these factors are often chosen as a target for treatment of acute kidney injury (AKI) in a variety of experimental and clinical studies. Note, that since these two components are closely interrelated during AKI development, substances that treat one of the processes often affect the other. The review considers several groups of promising nephroprotectors that have both anti-inflammatory and antioxidant effects. For example, many antioxidants, such as vitamins, polyphenolic compounds, and mitochondria-targeted antioxidants, not only reduce production of the reactive oxygen species in the cell but also modulate activity of the immune cells. On the other hand, immunosuppressors and non-steroidal anti-inflammatory drugs that primarily affect inflammation also reduce oxidative stress under some conditions. Another group of therapeutics is represented by hormones, such as estrogens and melatonin, which significantly reduce severity of the kidney damage through modulation of both these processes. We conclude that drugs with combined anti-inflammatory and antioxidant capacities are the most promising agents for the treatment of acute ischemic kidney injury.

Intravenous immunoglobulin treatment for patients with severe COVID-19: a retrospective multicentre study

Objectives

Intravenous immunoglobulin (IVIG) is commonly used to treat severe COVID-19, although the clinical outcome of such treatment remains unclear. This study evaluated the effectiveness of IVIG treatment in severe COVID-19 patients.

Methods

This retrospective multicentre study evaluated 28-day mortality in severe COVID-19 patients with or without IVIG treatment. Each patient treated with IVIG was matched with one untreated patient. Logistic regression and inverse probability weighting (IPW) were used to control confounding factors.

Results

The study included 850 patients (421 IVIG-treated patients and 429 non-IVIG-treated patients). After matching, 406 patients per group remained. No significant difference in 28-day mortality was observed after IPW analysis (average treatment effect (ATE) = 0.008, 95% CI –0.081 to 0.097, p 0.863). There were no significant differences between the IVIG group and non-IVIG group for acute respiratory distress syndrome, diffuse intravascular coagulation, myocardial injury, acute hepatic injury, shock, acute kidney injury, non-invasive mechanical ventilation, invasive mechanical ventilation, continuous renal replacement therapy and extracorporeal membrane oxygenation except for prone position ventilation (ATE = –0.022, 95% CI –0.041 to –0.002, p 0.028).

Discussion

IVIG treatment was not associated with significant changes in 28-day mortality in severe COVID-19 patients. The effectiveness of IVIG in treating patients with severe COVID-19 needs to be further investigated through future studies.

Perioperative alterations in the intestinal microbiota and functional changes mediate innate immune activation after small bowel transplantation

AIM

Small bowel transplantation (SBT) is the only therapy for end-stage short bowel syndrome. However, complicated pathological changes and an increased risk of postoperative infections in the perioperative period are major obstacles to patient survival, but the associated mechanisms remain unclear.

METHODS

To explore perioperative alterations in the intestinal microbiota and their functional changes after SBT, 16S rRNA sequencing of ileostomy effluents and plasma analysis were performed pre-SBT and periodically post-SBT.

RESULTS

The results suggested that the presence of Proteobacteria accelerated bacterial motility and chemotaxis during the first week in post-SBT recipients. Altered gut microbiota impaired intestinal barrier integrity and upregulated 16S rDNA, pathogen-associated molecular pattern (PAMP) and pattern-recognition molecule (PRM) levels in peripheral circulation. Importantly, the levels of neutrophils, monocytes, cytotoxic T lymphocytes, and natural killer cells and the expression of proinflammatory cytokines were increased in the peripheral blood and had potential roles in activating innate immune-mediated inflammatory injury after SBT.

CONCLUSION

Together, our results suggest that altered microbiota and functional changes are probably related to innate immune-mediated inflammatory injury and graft survival after SBT, suggesting that the monitoring and regulation of intestinal microbiota are necessary for SBT patients.

Prednisone is genotoxic in mice and Drosophila melanogaster

Prednisone (PD) is one of the most commonly used corticosteroids in immunosuppressive therapy for patients with autoimmune diseases and transplants. Chronic use of corticosteroids is associated with several side effects and an increase in neoplasia. Since genotoxic effects are associated with an increased risk of cancer development, this study evaluated the genotoxic and cytotoxic activities of PD using the SMART/wing assay in Drosophila melanogaster and the micronucleus test and comet assay in mouse bone marrow cells. Further, the toxic effects of PD on mouse organ tissues were assessed using histopathological analyses. In the SMART/wing assay, PD showed a significant genotoxic activity at all concentrations tested (0.375, 0.75, 1.5, and 2.0 mg/mL) compared to the negative control (p < 0.05). The micronucleus test and comet assay also showed an elevated genotoxicity of PD at all treatment conditions (24, 48, and 120 h with doses ranging from 0.5 to 1.5 mg/kg) compared to the negative control (p < 0.05). The histopathological analyses did not show toxicity of PD in mouse cells and tissues. Therefore, our results demonstrate that PD is a potent genotoxic immunosuppressant in mice and D. melanogaster cells. Somatic recombination was the primary contributor (46%-82%) to the induced genotoxicity observed in the SMART test.

Dendritic cells transduced with TIPE-2 recombinant adenovirus induces T cells suppression

INTRODUCTION

TIPE-2 has been identified as a negative regulator of both innate and adaptive immunity and is involved in several inflammatory diseases. However, the role of immune suppression of dendritic cells (DCs) transduced with TIPE-2 has not been well studied.

METHODS

In this study, DCs were transduced with TIPE-2 recombinant adenovirus, and then were cocultured with allogeneic CD4+ or CD8 + T cells. The proliferation, cytokine production and activation marker levels of CD4+ or CD8 + T cell were detected.

RESULTS

The data demonstrated that T cell proliferation, cytokine production and activation marker levels were attenuated after treated with TIPE-2 transduced DCs.

CONCLUSIONS

These results suggested that TIPE-2 transduced DCs are capable of inducing allogeneic CD4+ or CD8 + T cell immune suppression, which provide a promising way for the therapeutical strategies of transplantation or autoimmune diseases.

Immune responses to azacytidine in animal models of inflammatory disorders: a systematic review

Inflammatory disorders like diabetes, systemic lupus erythematodes, inflammatory lung diseases, rheumatoid arthritis and multiple sclerosis, but also rejection of transplanted organs and GvHD, form a major burden of disease. Current classes of immune suppressive drugs to treat these disorders are never curative and side effects are common. Therefore there is a need for new drugs with improved and more targeted modes of action. Potential candidates are the DNA methyl transferase inhibitor 5-azacytidine (Aza) and its derivative 5-aza 2′deoxycitidine (DAC). Aza and DAC have been tested in several pre-clinical in vivo studies. In order to obtain an overview of disorders for which Aza and/or DAC can be a potential treatment, and to find out where information is lacking, we systematically reviewed pre-clinical animal studies assessing Aza or DAC as a potential therapy for distinct inflammatory disorders. Also, study quality and risk of bias was systematically assessed. In the 35 identified studies, we show that both Aza and DAC do not only seem to be able to alleviate a number of inflammatory disorders, but also prevent solid organ rejection and GvHD in in vivo pre-clinical animal models. Aza/DAC are known to upregulate FOXP3, a master transcription factor for Treg, in vitro. Seventeen studies described the effect on Treg, of which 16 studies showed an increase in Treg. Increasing Treg therefore seems to be a common mechanism in preventing inflammatory disorders by Aza/DAC. We also found, however, that many essential methodological details were poorly reported leading to an unclear risk of bias. Therefore, reported effects might be an overestimation of the true effect.

A Review of Infections After Hematopoietic Cell Transplantation Requiring PICU Care: Transplant Timeline Is Key

Despite major advances in antimicrobial prophylaxis and therapy, opportunistic infections remain a major cause of morbidity and mortality after pediatric hematopoietic cell transplant (HCT). Risk factors associated with the development of opportunistic infections include the patient's underlying disease, previous infection history, co-morbidities, source of the donor graft, preparative therapy prior to the graft infusion, immunosuppressive agents, early and late toxicities after transplant, and graft-vs.-host disease (GVHD). Additionally, the risk for and type of infection changes throughout the HCT course and is greatly influenced by the degree and duration of immunosuppression of the HCT recipient. Hematopoietic cell transplant recipients are at high risk for rapid clinical decompensation from infections. The pediatric intensivist must remain abreast of the status of the timeline from HCT to understand the risk for different infections. This review will serve to highlight the infection risks over the year-long course of the HCT process and to provide key clinical considerations for the pediatric intensivist by presenting a series of hypothetical HCT cases.

Adverse events in second- and third-line treatments for acute and chronic graft-versus-host disease: systematic review

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is associated with an increased risk of graft-versus-host disease (GvHD), a strong prognostic predictor of early mortality within the first 2 years following allo-HSCT. The objective of this study was to describe the harm outcomes reported among patients receiving second- and third-line treatment as part of the management for GvHD via a systematic literature review.

METHODS

A total of 34 studies met the systematic review inclusion criteria, reporting adverse events (AEs) across 12 different second- and third-line therapies.

RESULTS

A total of 14 studies reported AEs across nine different therapies used in the treatment of acute GvHD (aGvHD), 17 studies reported AEs of eight different treatments for chronic GvHD (cGvHD) and 3 reported a mixed population. Infections were the AE reported most widely, followed by haematologic events and laboratory abnormalities. Reported infections per patient were lower under extracorporeal photopheresis (ECP) for aGvHD (0.267 infections per patient over 6 months) relative to any of the therapies studied (ranging from 0.853 infections per patient per 6 months under etanercept up to 1.998 infections per patient on inolimomab).

CONCLUSION

The reported incidence of infectious AEs in aGvHD and grade 3-5 AEs in cGvHD was lower on ECP compared with pharmaceutical management.

Stem/progenitor cell-based transplantation for retinal degeneration: a review of clinical trials

Retinal degeneration (RD) is one of the dominant causes of irreversible vision impairment and blindness worldwide. However, the current effective therapeutics for RD in the ophthalmologic clinic are unclear and controversial. In recent years, extensively investigated stem/progenitor cells—including retinal progenitor cells (RPCs), embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs) and mesenchymal stromal cells (MSCs)—with proliferation and multidirectional differentiation potential have presented opportunities to revolutionise the ultimate clinical management of RD. Herein, we provide a comprehensive overview on the progression of clinical trials for RD treatment using four types of stem/progenitor cell-based transplantation to replace degenerative retinal cells and/or to supplement trophic factors from the aspects of safety, effectiveness and their respective advantages and disadvantages. In addition, we also discuss the emerging role of stem cells in the secretion of multifunctional nanoscale exosomes by which stem cells could be further exploited as a potential RD therapy. This review will facilitate the understanding of scientists and clinicians of the enormous promise of stem/progenitor cell-based transplantation for RD treatment, and provide incentive for superior employment of such strategies that may be suitable for treatment of other diseases, such as stroke and ischaemia–reperfusion injury.

Autophagy in endothelial cells regulates their haematopoiesis-supporting ability

Background

Endothelial cells (ECs) function as an instructive platform to support haematopoietic stem cell (HSC) homeostasis. Our recent studies found that impaired bone marrow (BM) ECs are responsible for the defective haematopoiesis in patients with poor graft function (PGF), which is characterised by pancytopenia post-allotransplant. Although activated autophagy was reported to benefit ECs, whether EC autophagy plays a critical role in supporting HSCs and its effect on PGF patients post-allotransplant remain unclear.

Methods

To evaluate whether the autophagy status of ECs modulates their ability to support haematopoiesis, human umbilical vein endothelial cells (HUVECs) and primary BM ECs derived from healthy donors were subjected to knockdown or overexpression of Beclin-1 (an autophagy-related protein). Moreover, BM ECs derived from PGF patients were studied.

Findings

Beclin-1 knockdown significantly reduced the haematopoiesis-supporting ability of ECs by suppressing autophagy, which could be restored by activating autophagy via Beclin-1 upregulation. Moreover, autophagy positively regulated haematopoiesis-related genes in HUVECs. Subsequently, a prospective case-control study demonstrated that defective autophagy reduced Beclin-1 expression and the colony-forming unit (CFU) plating efficiency in BM ECs from PGF patients compared to matched patients with good graft function. Rapamycin, an autophagy activator, quantitatively and functionally improved BM ECs from PGF patients in vitro and enhanced their ability to support HSCs by activating the Beclin-1 pathway.

Interpretation

Our results suggest that the autophagy status of ECs modulates their ability to support haematopoiesis by regulating the Beclin-1 pathway. Defective autophagy in BM ECs may be involved in the pathogenesis of PGF post-allotransplant. Rapamycin provides a promising therapeutic approach for PGF patients.

Funding

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Selective Effects of mTOR Inhibitor Sirolimus on Naïve and CMV-Specific T Cells Extending Its Applicable Range Beyond Immunosuppression

Cytomegalovirus (CMV) infection/reactivation remains among the most important complications of immunosuppression after transplantation. However, recent clinical observations indicate that mammalian target of rapamycin (mTOR) inhibition with sirolimus may improve the outcome of CMV complications. Underlying mechanisms of this observation, particularly the effect of sirolimus on naïve- and CMV-specific cytotoxic CD8⁺ T-cell (CMV-CTL) functionality is still undiscovered. Here, the influence of sirolimus on naïve and memory CMV-CTLs was determined by CD3/CD28 crosslinking and alloreactivity assays. After stimulating CMV-CTL with HLA-A^*02:01-restricted CMVpp65-peptide loaded artificial antigen-presenting cells (aAPCs), we measured the effect of sirolimus on T-cell proliferation, phenotype, and functionality. Sirolimus significantly improved CMV-specific effector memory T-cell function and negatively influenced naïve T cells. This unique mechanism of action was further characterized by increased secretion of interferon-gamma (IFN-γ), granzyme B (GzB) and enhanced target-cell-dependent cytotoxic capacity of activated CMV-CTLs. Next-generation-sequencing (NGS) was applied to monitor T-cell receptor (TCR)-repertoire dynamics and to verify, that the increased functionality was not related to sirolimus-resistant CTL-clones. Instead, modulation of environmental cues during CMV-CTL development via IL-2 receptor (IL-2R)-driven signal transducer and activator of transcription-5 (STAT-5) signaling under mTOR inhibition allowed fine-tuning of T-cell programming for enhanced antiviral response with stable TCR-repertoire dynamics. We show for the first time that sirolimus acts selectively on human naïve and memory T cells and improves CMV-specific T-cell function via modulation of the environmental milieu. The data emphasize the importance to extend immune monitoring including cytokine levels and T-cell functionality which will help to identify patients who may benefit from individually tailored immunosuppression.

Oral shedding of HSV-1 and EBV and oral manifestations in paediatric chronic kidney disease patients and renal transplant recipients

OBJECTIVE

Previous research demonstrated that salivary shedding of HSV-1 and EBV occurs often in adult renal transplant recipients, but there is a lack of studies on the presence of them in the saliva of paediatric population. Therefore, the objective of this study is to describe oral characteristics and to compare the shedding profile of HSV-1 and EBV in the saliva of children with renal transplant to that of chronic kidney disease patients and controls.

METHODS

This is a cross-sectional study involving 100 children, being 25 renal transplant recipients, 25 chronic kidney disease patients and 50 healthy children. Demographic and oral clinical characteristics were assessed. Saliva samples were collected and submitted to screening for EBV and HSV-1 by using nested polymerase chain reaction technique. Fisher's exact, Pearson's chi-square and Kruskal-Wallis tests were used for statistical analysis at a significance level of 5%.

RESULTS

Oral shedding of HSV-1 (28%) and EBV (60%) were significantly higher in renal transplant recipients compared to the other groups. Single vesicles in the oral mucosa were statistically associated with the presence of HSV-1 (p = .035). In children with chronic kidney disease, there was a higher prevalence of pale oral mucosa (32%) and enamel hypoplasia (40%) compared to paediatric renal transplant recipients and controls. Dental calculus (36%), candidiasis (8%), drug-induced gingival overgrowth (16%), mouth blisters (8%), xerostomia (12%) and salivary gland enlargement (20%) were more common in paediatric renal transplant recipients.

CONCLUSIONS

Therefore, it can be concluded that salivary shedding of HSV-1 and EBV in paediatric patients was more often found in renal transplant recipients than in the renal failure and control children. Transplanted recipients showed more oral manifestations than renal failure and control children did.

Cutaneous Toxicities From Transplantation-Related Medications

Despite the abundance of information on cutaneous malignancies associated with solid organ transplantation in the transplant literature, there is limited information regarding nonmalignant skin changes after transplantation. There are numerous skin toxicities secondary to immunosuppressive and other transplant-related medications that can vary in presentation, severity, and prognosis. To limit associated morbidity and mortality, solid organ transplant recipient care providers should effectively identify and manage cutaneous manifestations secondary to drug toxicity. Toxicities from the following transplant-related medications will be discussed: antithymocyte globulins, systemic steroids, cyclosporine, tacrolimus, azathioprine, mycophenolate mofetil, mammalian target of rapamycin inhibitors sirolimus and everolimus, basiliximab and daclizumab, belatacept, and voriconazole.

Evaluation of electrochemiluminescence immunoassays for immunosuppressive drugs on the Roche cobas e411 analyzer

Background:  Therapeutic drug monitoring of immunosuppressant drugs are used to monitor drug efficacy and toxicity and to prevent organ transplant rejection. This study evaluates the analytical performance of semi-automated electrochemiluminescence immunoassays (ECLIA) for cyclosporine (CSA), tacrolimus (TAC) and sirolimus (SRL) on the Roche cobas e 411 analyzer at a major transplant hospital to assess method suitability and limitations.

Methods: Residual whole blood samples from patients undergoing immunosuppressant therapy were used for evaluation. Imprecision, linearity, functional sensitivity, method comparisons and lot-to-lot comparisons were assessed.

Results: Total imprecision ranged from 3.3 to 7.1% for CSA, 3.9 to 9.4% for TAC, and 4.6 to 8.2% for SRL. Linearity was verified from 30.0 to 960.9 μg/L for CSA, from 1.1 to 27.1 μg/L for TAC, and from 0.5 to 32.3 µg/L for SRL. The functional sensitivity met the manufacturer’s claims and was determined to be <6.5 μg/L for CSA, 1.1 μg/L for TAC, and <0.1 µg/L for SRL (CV≤20%). Deming regression analysis of method comparisons with the ARCHITECT immunoassay yielded slopes of 0.917 (95%CI: 0.885-0.949) and r of 0.985 for CSA, 0.938 (95%CI: 0.895-0.981) and r of 0.974 for TAC, and 0.842 (0.810-1.110) and r of 0.982 for SRL. Deming regression analysis of comparisons with the LC–MS/MS method yielded slopes of 1.331 (95%CI: 1.167-1.496) and r of 0.969 for CSA, 0.924 (95%CI: 0.843-1.005) and r of 0.984 for TAC, and 0.971 (95%CI: 0.913-1.030) and r of 0.993 for SRL.

Conclusions: The cobas e 411 ECLIA for CSA, TAC, and SRL have acceptable precision, linearity, and functional sensitivity. The method comparisons correlated well with the ARCHITECT immunoassay and LC–MS/MS and is fit for therapeutic drug monitoring

An engineered bispecific DNA-encoded IgG antibody protects against Pseudomonas aeruginosa in a pneumonia challenge model

The impact of broad-spectrum antibiotics on antimicrobial resistance and disruption of the beneficial microbiome compels the urgent investigation of bacteria-specific approaches such as antibody-based strategies. Among these, DNA-delivered monoclonal antibodies (DMAbs), produced by muscle cells in vivo, potentially allow the prevention or treatment of bacterial infections circumventing some of the hurdles of protein IgG delivery. Here, we optimize DNA-delivered monoclonal antibodies consisting of two potent human IgG clones, including a non-natural bispecific IgG1 candidate, targeting Pseudomonas aeruginosa. The DNA-delivered monoclonal antibodies exhibit indistinguishable potency compared to bioprocessed IgG and protect against lethal pneumonia in mice. The DNA-delivered monoclonal antibodies decrease bacterial colonization of organs and exhibit enhanced adjunctive activity in combination with antibiotics. These studies support DNA-delivered monoclonal antibodies delivery as a potential strategy to augment the host immune response to prevent serious bacterial infections, and represent a significant advancement toward broader practical delivery of monoclonal antibody immunotherapeutics for additional infectious pathogens.

DNA-delivered monoclonal antibodies (DMAbs) can be produced by muscle cells in vivo, potentially allowing prevention or treatment of infectious diseases. Here, the authors show that two DMAbs targeting Pseudomonas aeruginosa proteins confer protection against lethal pneumonia in mice.

Comparative global immune-related gene profiling of somatic cells, human pluripotent stem cells and their derivatives: implication for human lymphocyte proliferation

Human pluripotent stem cells (hPSCs), including embryonic stem cells (ESCs) and induced PSCs (iPSCs), represent potentially unlimited cell sources for clinical applications. Previous studies have suggested that hPSCs may benefit from immune privilege and limited immunogenicity, as reflected by the reduced expression of major histocompatibility complex class-related molecules. Here we investigated the global immune-related gene expression profiles of human ESCs, hiPSCs and somatic cells and identified candidate immune-related genes that may alter their immunogenicity. The expression levels of global immune-related genes were determined by comparing undifferentiated and differentiated stem cells and three types of human somatic cells: dermal papilla cells, ovarian granulosa cells and foreskin fibroblast cells. We identified the differentially expressed genes CD24, GATA3, PROM1, THBS2, LY96, IFIT3, CXCR4, IL1R1, FGFR3, IDO1 and KDR, which overlapped with selected immune-related gene lists. In further analyses, mammalian target of rapamycin complex (mTOR) signaling was investigated in the differentiated stem cells following treatment with rapamycin and lentiviral transduction with specific short-hairpin RNAs. We found that the inhibition of mTOR signal pathways significantly downregulated the immunogenicity of differentiated stem cells. We also tested the immune responses induced in differentiated stem cells by mixed lymphocyte reactions. We found that CD24- and GATA3-deficient differentiated stem cells including neural lineage cells had limited abilities to activate human lymphocytes. By analyzing the transcriptome signature of immune-related genes, we observed a tendency of the hPSCs to differentiate toward an immune cell phenotype. Taken together, these data identify candidate immune-related genes that might constitute valuable targets for clinical applications.

Inhibition of allogeneic cytotoxic T cell (CD8+) proliferation via polymer-induced Treg (CD4+) cells

T cell-mediated immune rejection remains a barrier to successful transplantation. Polymer-based bioengineering of cells may provide an effective means of preventing allorecognition and the proliferation of cytotoxic (CD8⁺) T lymphocytes (CTL). Using MHC-disparate murine splenocytes modified with succinimidyl valerate activated methoxypoly(ethylene glycol) [SVA-mPEG] polymers, the effects of leukocyte immunocamouflage on CD8⁺ and CD4⁺ alloproliferation and T regulatory (Treg) cell induction were assessed in a mixed lymphocyte reaction (MLR) model. Polymer-grafting effectively camouflaged multiple leukocyte markers (MHC class I and II, TCR and CD3) essential for effective allorecognition. Consequent to the polymer-induced immunocamouflage of the cell membrane, both CD8⁺ and CD4⁺ T cell alloproliferation were significantly inhibited in a polymer dose-dependent manner. The loss of alloproliferation correlated with the induction of Treg cells (CD4⁺CD25⁺Foxp3⁺). The Tregs, surprisingly, arose primarily via differentiation of naive, non-proliferating, CD4⁺ cells. Of biologic importance, the polymer-induced Treg were functional and exhibited potent immunosuppressive activity on allogeneic CTL proliferation. These results suggest that immunocamouflage-mediated attenuation of alloantigen-TCR recognition can prevent the tissue destructive allogeneic CD8⁺ T cell response, both directly and indirectly, through the generation/differentiation of functional Tregs. Immunocamouflage induced tolerance could be clinically valuable in attenuating T cell-mediated transplant rejection and in the treatment of autoimmune diseases.

STATEMENT OF SIGNIFICANCE

While our previous studies have demonstrated that polymer-grafting to MHC disparate leukocytes inhibits CD4⁺ cell proliferation, the effects of PEGylation on the alloproliferation of CD8⁺ cytotoxic T cells (CTL) was not examined. As shown here, PEGylation of allogeneic leukocytes prevents the generation of the CTL response responsible for acute rejection. The loss of CTL proliferation is consequent to the polymer-based attenuation of allorecognition and the induction of T regulatory cells (Tregs). Interestingly, the Tregs are primarily generated via the differentiation of non-proliferating naive T cells. Importantly, the Tregs are functional and effectively induce a tolerogenic environment when transferred to an alloresponsive environment. The use of polymer-modified leukocytes provides a unique approach to effectively maximize the biologic production of functional Tregs both in vitro and in vivo. By using this approach it may be possible to attenuate unwanted alloresponses (e.g., graft rejection) or to treat autoimmune diseases.

Nanotechnological Approaches to Immunosuppression and Tolerance Induction

PURPOSE OF REVIEW

Several preclinical studies have engineered nanoparticles for immune regulation, and have shown promising results in the fields of autoimmunity and cancer. In solid organ transplantation, the use of nanoparticle-based immune regulation has only just begun to emerge but holds significant promise for the improvement of our current standard of care immunosuppressive regimens. In this review, we will shed light on the current status of nanoparticle-engineered immunotherapeutics, and the potential application of these technologies to the field of organ transplantation. Further we discuss different strategies for delivery and potential cellular targeting moieties that could be utilized to obviate the need for high dose systemic immunosuppressive regimens.

RECENT FINDINGS

Recent studies have shown the potential of immunosuppressive laden nanoparticles to increase bioavailability, drug release, and specifically target immune cell compartments as methods to provide recipient immunosuppressive sparing strategies.

SUMMARY

Nanoparticle centered immunosuppressive strategies hold the potential to usher in a new era in transplant recipient management and could hold the key to minimizing off-target effects of immunosuppressants, along with prolonging transplant survival.

Synthetic Biology in Cell and Organ Transplantation

The transplantation of cells and organs has an extensive history, with blood transfusion and skin grafts described as some of the earliest medical interventions. The speed and efficiency of the human immune system evolved to rapidly recognize and remove pathogens; the human immune system also serves as a barrier against the transplant of cells and organs from even highly related donors. Although this shows the remarkable effectiveness of the immune system, the engineering of cells and organs that will survive in a host patient over the long term remains a steep challenge. Progress in the understanding of host immune responses to donor cells and organs, combined with the rapid advancement in synthetic biology applications, allows the rational engineering of more effective solutions for transplantation.