Interleukin-6, A Cytokine Critical to Mediation of Inflammation, Autoimmunity and Allograft Rejection: Therapeutic Implications of IL-6 Receptor Blockade. Transplantation. 2017;101:32-44. [PMID: 27547870 DOI: 10.1097/tp.0000000000001452]

Src inhibition modulates AMBRA1-mediated mitophagy to counteract endothelial-to-mesenchymal transition in renal allograft fibrosis

Chronic allograft dysfunction (CAD) poses a significant challenge in kidney transplantation, with renal vascular endothelial-to-mesenchymal transition (EndMT) playing a vital role. While renal vascular EndMT has been verified as an important contributing factor to renal allograft interstitial fibrosis/tubular atrophy in CAD patients, its underlying mechanisms remain obscure. Currently, Src activation is closely linked to organ fibrosis development. Single-cell transcriptomic analysis in clinical patients revealed that Src is a potential pivotal mediator in CAD progression. Our findings revealed a significant upregulation of Src which closely associated with EndMT in CAD patients, allogeneic kidney transplanted rats and endothelial cells lines. In vivo, Src inhibition remarkably alleviate EndMT and renal allograft interstitial fibrosis in allogeneic kidney transplanted rats. It also had a similar antifibrotic effect in two endothelial cell lines. Mechanistically, the knockout of Src resulted in an augmented AMBRA1-mediated mitophagy in endothelial cells. We demonstrate that Src knockdown upregulates AMBRA1 level and activates mitophagy by stabilizing Parkin's ubiquitination levels and mitochondrial translocation. Subsequent experiments demonstrated that the knockdown of the Parkin gene inhibited mitophagy in endothelial cells, leading to increased production of Interleukin-6, thereby inducing EndMT. Consequently, our study underscores Src as a critical mediator of renal vascular EndMT and allograft interstitial fibrosis, exerting its impact through the regulation of AMBRA1/Parkin-mediated mitophagy.

Serum IL-6 predicts risk of kidney transplant failure independently of immunological risk

Interleukin-6 (IL-6) is an important immune mediator and a target for novel antibody therapies. In this study, we aimed to determine whether serum IL-6 levels are associated with immunological risk, allograft rejection and outcomes in kidney transplant (Ktx) patients. We retrospectively analyzed the data of 104 patients who underwent Ktx at our center between 2011 and 2015. The patients were divided into high- and low-risk groups (n = 52 per group) based on panel reactive antibody (PRA) percentage ≥ 35%, the existence of pre-Ktx donor-specific antibodies (DSA), or a previous transplant. IL-6 concentrations were measured before and at 3 months, 12 months, and 3 years after Ktx. Serum IL-6 levels tended to be higher in high-risk patients than in low-risk patients prior to Ktx and at 12 months after Ktx; however, the difference did not reach statistical significance (pre-Ktx, high-risk: 1.995 ± 2.79 pg/ml vs. low-risk: 1.43 ± 1.76 pg/ml, p = 0.051; 12 mo. high-risk: 1.16 ± 1.87 pg/ml vs. low-risk: 0.78 ± 1.13 pg/ml, p = 0.067). IL-6 levels were correlated with the types (no rejection, T cell mediated rejection (TCMR), antibody-mediated rejection (ABMR), or both) and time (<1 year vs. >1 year after Ktx) of rejection, as well as patient and graft survival. Patients with both TCMR and ABMR had significantly higher IL-6 levels at 3 months (14.1 ± 25.2 pg/ml) than patients with ABMR (3.4 ± 4.8 pg/ml, p = 0.017), with TCMR (1.7 ± 1.3 pg/ml, p < 0.001), and without rejection (1.7 ± 1.4 pg/ml, p < 0.001). Three years after Ktx, patients with AMBR had significantly higher IL-6 levels (5.30 ± 7.66 pg/ml) than patients with TCMR (1.81 ± 1.61 pg/ml, p = 0.009) and patients without rejection (1.19 ± 0.95 pg/ml; p = 0.001). Moreover, three years after Ktx IL-6 levels were significantly higher in patients with late rejections (3.5 ± 5.4 pg/ml) than those without rejections (1.2 ± 1.0 pg/ml) (p = 0.006). The risk of death-censored graft failure was significantly increased in patients with elevated IL-6 levels at 12 months (IL-6 level > 1.396 pg/ml, HR 4.61, p = 0.007) and 3 years (IL-6 level > 1.976 pg/ml, HR 6.75, p = 0.003), but elevated IL-6 levels were not associated with a higher risk of death. Overall, our study highlights IL-6 as a risk factor for allograft failure and confirms that IL-6 levels are higher in patients developing ABMR compared to TCMR alone or no rejection.

Comparison of the chemical constituents of Saposhnikoviae Radix associated with three different growth patterns and its therapeutic effect against atopic dermatitis

ETHNOPHARMACOLOGICAL RELEVANCE

Saposhnikoviae Radix (SR) was initially documented in Shennong Bencao Jing classics for its properties in dispelling wind, dissolving surface, relieving pain, and alleviating spasms. This herb is commonly used in traditional Chinese medicine to address conditions that affect the body's surface, by aiding in the expulsion of pathogens from the surface and alleviating pain associated with the immune response. Atopic dermatitis (AD) is a prevalent allergic skin disorder, and the therapeutic effects of SR in dispelling wind and relieving the body's surface are consistent with the clinical symptoms commonly observed in AD.

AIM OF THE STUDY

The anti-AD effects of SR were examined under three different growth patterns to identify active pharmacodynamic compounds. The results provide insight into the clinical efficacy of wild and cultivated SR.

MATERIALS AND METHODS

The efficacy of wild, wild-simulated, and cultivated SR was assessed in a mouse model of AD. In addition, the effects of wild and varying doses of cultivated SR were evaluated in mice with short-term AD symptoms. GC-MS and UPLC-MS/MS were used to analyze the chemical components of the three SR treatments and molecular docking was used to identify active components.

RESULTS

A mouse model of AD was used to assess the pharmacodynamic effects of SR prepared by three different cultivation methods. The study found that all three SR preparations improved phenotypic markers and histopathological features in the AD mouse model. The efficacy of wild SR and wild-simulated SR was similar, although there was a significant difference between wild and cultivated SR. Both wild SR and various doses of cultivated SR ameliorated skin injuries and reduced inflammation in serum and skin tissues. Furthermore, skin thickness, inflammatory cells, mast cell infiltration, and IL-33 expression improved following treatment. Notably, wild SR, double-cultivated SR, and triple-cultivated SR demonstrated significant therapeutic effects. An analysis using GC-MS revealed the presence of 55, 52, and 43 volatile oils in the three SR preparations, with more common components observed between wild and wild-simulated SR. Fewer common components were evident between cultivated and wild SR. UPLC-MS/MS analysis identified a total of 37 compounds, with larger relative peak areas observed for the chromogenic ketones. Molecular docking studies revealed that certain compounds, such as n-propyl 9,12-octadecadienoate, (E)-9-octadecenoic acid ethyl ester, and various chromogenic ketones, such as cimifugin, 5-O-methyIvisamminol, hamaudol, 3'-O-acetylhamaudol, 3'-O-angeloyhamandol, adenosine and farnesylaceton, may be the major substances that distinguish the activities of SR with three different growth patterns.

CONCLUSION

Variations in the anti-AD efficacy of SR with three growth patterns were identified, and their chemical composition differences were determined. These findings suggest that increasing the dosage of cultivated SR could potentially be a viable clinical alternative for atopic dermatitis treatment.

Absence of IL-6 Receptor Blockade Effect on the Outcomes of Transplant Glomerulopathy in the Absence of Anti-HLA Donor-specific Antibodies

Background

Transplant glomerulopathy (TG) is the hallmark of chronic antibody-mediated rejection but often occurs without anti-HLA donor-specific antibodies (DSAs) in the assumption that other DSAs may be the effectors of the tissue injury. Recently, we reported a positive effect of interleukin-6 (IL-6) receptor blocker tocilizumab (TCZ) in TG/DSA+. In the present study, we investigate the effect of TCZ in a cohort of TG cases without detectable anti-HLA DSAs.

Methods

Single-center retrospective analysis of TG cases without anti-HLA DSAs (TG/DSA) treated with TCZ for chronic antibody-mediated rejection as first-line therapy evaluated through clinical, protocol biopsies, and gene expression analyses was included.

Results

Differently from TG/DSA+, TG/DSA- showed a progressive reduction in the estimated glomerular filtration rate at 12 mo and after that with no significant modification in microvascular inflammation or C4d+. No upregulation in tight junction protein-1, aldo-keto reductase family 1 member C3, and calcium/calmodulin-dependent serine protein kinase, documented in TG/DSA+, was noted in post-TCZ biopsies. The reduction of microvascular inflammation was associated with natural killer-cell reduction in TG/DSA+, whereas TG/DSA- tends to maintain or increase periglomerular/interstitial infiltration.

Conclusions

In the absence of anti-HLA DSAs, TG behavior seems not to be modified by IL-6 receptor blockade. These results are at variance with observational studies and previous trials with IL-6 inhibitors in TG associated with anti-HLA DSAs. These data may fuel the hypothesis of different mechanisms underlying TGs (including the potentially different roles of natural killer cells) and suggest carefully selecting patients with TG for clinical trials or off-label treatment based on their antidonor serologic status.

Targeting interleukin-6 as a treatment approach for peritoneal carcinomatosis

Peritoneal carcinomatosis (PC) is a complex manifestation of abdominal cancers, with a poor prognosis and limited treatment options. Recent work identifying high concentrations of the cytokine interleukin-6 (IL-6) and its soluble receptor (sIL-6-Rα) in the peritoneal cavity of patients with PC has highlighted this pathway as an emerging potential therapeutic target. This review article provides a comprehensive overview of the current understanding of the potential role of IL-6 in the development and progression of PC. We discuss mechansims by which the IL-6 pathway may contribute to peritoneal tumor dissemination, mesothelial adhesion and invasion, stromal invasion and proliferation, and immune response modulation. Finally, we review the prospects for targeting the IL-6 pathway in the treatment of PC, focusing on common sites of origin, including ovarian, gastric, pancreatic, colorectal and appendiceal cancer, and mesothelioma.

Disulfiram treatment suppresses antibody-producing reactions by inhibiting macrophage activation and B cell pyrimidine metabolism

Antibody responses, involving B cells, CD4 + T cells, and macrophages, are implicated in autoimmune diseases and organ transplant rejection. We have previously shown that inhibiting FROUNT with disulfiram (DSF) suppresses macrophage activation and migration, effectively treating inflammatory diseases. In this study, we investigated the effectiveness of DSF in antibody-producing reactions. Using a heart transplantation mouse model with antibody-mediated rejection, we administered anti-CD8 antibody to exclude cellular rejection. DSF directly inhibited B cell responses in vitro and significantly reduced plasma donor-specific antibodies and graft antibody deposition in vivo, resulting in prolonged survival of the heart graft. DSF also mediated various effects, including decreased macrophage infiltration and increased Foxp3+ regulatory T-cells in the grafts. Additionally, DSF inhibited pyrimidine metabolism-related gene expression induced by B-cell stimulation. These findings demonstrate that DSF modulates antibody production in the immune response complexity by regulating B-cell and macrophage responses.

Synthesis of novel nonsteroidal anti-inflammatory galloyl β-sitosterol-loaded lignin-capped Ag-based drug

Biocompatible anti-inflammatory lignin-capped Ag (LCAg) nanoparticles (NPs) were synthesized for the delivery of galloyl β-sitosterol (Galloyl-BS). β-Sitosterol (BS) is effective against inflammatory responses, like cancer-induced inflammations. BS was modified via gallic acid esterification to enhance its anti-inflammatory potential. LCAg NPs were synthesized by a green method and loaded with galloyl-BS. For comparison, pure BS was also loaded onto LCAg NPs in a separate assembly. The antioxidant potential of Galloyl-BS was greater (IC50 177 µM) than pure BS. Materials were characterized by FT-IR, SEM, XRD, and Zeta potential. Using UV-Vis spectroscopy, drug release experiments were performed by varying pH, time, concentration, and temperature. Maximum drug release was observed after 18 h at pH 6 and 40 °C. Galloyl-BS showed improved drug loading efficiency, release %age, and antioxidant activity compared to pure BS when loaded onto LCAg NPs. DLCAg exhibited excellent anti-inflammatory activity in rat models. These findings indicate that galloyl-BS (drug)-loaded LCAg (DLCAg) NPs have the potential as an anti-inflammatory agent without any prior release and scavenging in normal cells.

Tocilizumab in chronic active antibody-mediated rejection: rationale and protocol of an in-progress randomized controlled open-label multi-center trial (INTERCEPT study)

BACKGROUND

Chronic active antibody-mediated rejection (caAMR) in kidney transplants is associated with irreversible tissue damage and a leading cause of graft loss in the long-term. However, the treatment for caAMR remains a challenge to date. Recently, tocilizumab, a recombinant humanized monoclonal antibody directed against the human interleukin-6 (IL-6) receptor, has shown promise in the treatment of caAMR. However, it has not been systematically investigated so far underscoring the need for randomized controlled studies in this area.

METHODS

The INTERCEPT study is an investigator-driven randomized controlled open-label multi-center trial in kidney transplant recipients to assess the efficacy of tocilizumab in the treatment of biopsy-proven caAMR. A total of 50 recipients with biopsy-proven caAMR at least 12 months after transplantation will be randomized to receive either tocilizumab (n = 25) added to our standard of care (SOC) maintenance treatment or SOC alone (n = 25) for a period of 24 months. Patients will be followed for an additional 12 months after cessation of study medication. After the inclusion biopsies at baseline, protocol kidney graft biopsies will be performed at 12 and 24 months. The sample size calculation assumed a difference of 5 ml/year in slope of estimated glomerular filtration rate (eGFR) between the two groups for 80% power at an alpha of 0.05. The primary endpoint is the slope of eGFR at 24 months after start of treatment. The secondary endpoints include assessment of the following at 12, 24, and 36 months: composite risk score iBox, safety, evolution and characteristics of donor-specific antibodies (DSA), graft histology, proteinuria, kidney function assessed by measured GFR (mGFR), patient- and death-censored graft survival, and patient-reported outcomes that include transplant-specific well-being, adherence to immunosuppressive medications and perceived threat of the risk of graft rejection.

DISCUSSION

No effective treatment exists for caAMR at present. Based on the hypothesis that inhibition of IL-6 receptor by tocilizumab will reduce antibody production and reduce antibody-mediated damage, our randomized trial has a potential to provide evidence for a novel treatment strategy for caAMR, therewith slowing the decline in graft function in the long-term.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04561986. Registered on September 24, 2020.

The novel selective TLR7 agonist GY101 suppresses colon cancer growth by stimulating immune cells

Toll-like receptor (TLR) 7, a transmembrane signal transduction receptor expressed on the surface of endosomes, has become an attractive target for antiviral and cancer immunotherapies. TLR7 can induce signal transduction by recognizing single-stranded RNA or its analogs, leading to the release of cytokines such as IL-6, IL-12, TNF-α and type-I IFN. Activation of TLR7 helps to enhance immunogenicity and immune memory by stimulating immune cells. Herein, we identified a novel selective TLR7 agonist, GY101, and determined its ability to activate TLR7. In summary, in vitro, compound GY101 significantly induced the secretion of IL-6, IL-12, TNF-α and IFN-γ in mouse splenic lymphocytes; in vivo, peritumoral injection of GY101 significantly suppressed colon cancer CT26, as well as poorly immunogenic B16-F10 and 4T1 cancer cell-derived tumor growth by activating the infiltration of lymphocytes and polarization of M2-like macrophages into M1-like macrophages. These results demonstrate that GY101, as a potent TLR7 agonist, holds great potential for cancer immunotherapy.

Management of the sensitized pediatric renal transplant candidate

Kidney transplantation is the treatment of choice for patients with ESRD as it is associated with improved patient survival and better quality of life, especially in children. There are several barriers to a successful transplant including organ shortage, anatomic barriers, and immunologic barriers. One of the biggest immunologic barriers that precludes transplantation is sensitization, when patients have antibodies prior to transplantation, resulting in positive crossmatches with donor. 30%-40% of adult patients on the wait list are sensitized. There is a growing number of pediatric patients on the wait list who are sensitized. This poses a unique challenge to the pediatric transplant community. Therefore, attempts to perform desensitization to remove or suppress pathogenic HLA antibodies resulting in acceptable crossmatches, and ultimately a successful transplant, while reducing the risk of acute rejection, are much needed in these children. This review article aims to address the management of such patients both prior to transplantation, with strategies to overcome sensitization, and after transplantation with monitoring for allograft rejection and other complications.

Feasibility of Interleukin-6 Receptor Blockade in Cardiac Antibody-mediated Rejection

BACKGROUND

Antibody-mediated rejection (AMR) remains a significant cause of heart transplant mortality with few effective therapies.

METHODS

This study aimed to describe initial experience of using interleukin-6 receptor blockade with tocilizumab in the treatment of acute cardiac AMR at Barnes-Jewish Hospital/Washington University Transplant Center from July 2017 to May 2021 (n = 7). Clinical, echocardiographic, and serum alloantibody data were analyzed before and after treatment.

RESULTS

All participants demonstrated marked improvement in functional status. Echocardiographic data following 4-6 mo of tocilizumab revealed significant improvements in biventricular systolic function for all participants. Consistent reductions in donor-specific HLA or angiotensin type I receptor antibodies were not observed, suggesting that tocilizumab may act downstream of antibody production. No patient experienced drug-related complications that necessitated discontinuation of therapy.

CONCLUSIONS

These findings provide initial insights into the safety and efficacy of interleukin-6 receptor blockade in the treatment of cardiac AMR and support the design of larger prospective studies.

Combined Use of Tocilizumab and Mesenchymal Stem Cells Attenuate the Development of an Anti-HLA-A2.1 Antibody in a Highly Sensitized Mouse Model

Sensitization to HLA can result in allograft loss for kidney transplantation (KT) patients. Therefore, it is required to develop an appropriate desensitization (DSZ) technique to remove HLA-donor-specific anti-HLA antibody (DSA) before KT. The aim of this research was to investigate whether combined use of the IL-6 receptor-blocking antibody, tocilizumab (TCZ), and bone-marrow-derived mesenchymal stem cells (BM-MSCs) could attenuate humoral immune responses in an allo-sensitized mouse model developed using HLA.A2 transgenic mice. Wild-type C57BL/6 mice were sensitized with skin allografts from C57BL/6-Tg (HLA-A2.1)1Enge/J mice and treated with TCZ, BM-MSC, or both TCZ and BM-MSC. We compared HLA.A2-specific IgG levels and subsets of T cells and B cells using flow cytometry among groups. HLA.A2-specific IgG level was decreased in all treated groups in comparison with that in the allo-sensitized control (Allo-CONT) group. Its decrease was the most significant in the TCZ + BM-MSC group. Regarding the B cell subset, combined use of TCZ and BM-MSC increased proportions of pre-pro B cells but decreased proportions of mature B cells in BM (p < 0.05 vs. control). In the spleen, an increase in transitional memory was observed with a significant decrease in marginal, follicular, and long-lived plasma B cells (p < 0.05 vs. control) in the TCZ + BM-MSC group. In T cell subsets, Th2 and Th17 cells were significantly decreased, but Treg cells were significantly increased in the TCZ+BM-MSC group compared to those in the Allo-CONT group in the spleen. Regarding RNA levels, IL-10 and Foxp3 showed increased expression, whereas IL-23 and IFN-γ showed decreased expression in the TCZ + BM-MSC group. In conclusion, combined use of TCZ and BM-MSC can inhibit B cell maturation and up-regulate Treg cells, finally resulting in the reduction of HLA.A2-specific IgG in a highly sensitized mouse model. This study suggests that the combined use of TCZ and BM-MSC can be proposed as a novel strategy in a desensitization protocol for highly sensitized patients.

The Na/K-ATPase role as a signal transducer in lung inflammation

Acute respiratory distress syndrome (ARDS) is marked by damage to the capillary endothelium and alveolar epithelium following edema formation and cell infiltration. Currently, there are no effective treatments for severe ARDS. Pathologies such as sepsis, pneumonia, fat embolism, and severe trauma may cause ARDS with respiratory failure. The primary mechanism of edema clearance is the epithelial cells' Na/K-ATPase (NKA) activity. NKA is an enzyme that maintains the electrochemical gradient and cell homeostasis by transporting Na+ and K+ ions across the cell membrane. Direct injury on alveolar cells or changes in ion transport caused by infections decreases the NKA activity, loosening tight junctions in epithelial cells and causing edema formation. In addition, NKA acts as a receptor triggering signal transduction in response to the binding of cardiac glycosides. The ouabain (a cardiac glycoside) and oleic acid induce lung injury by targeting NKA. Besides enzymatic inhibition, the NKA triggers intracellular signal transduction, fostering proinflammatory cytokines production and contributing to lung injury. Herein, we reviewed and discussed the crucial role of NKA in edema clearance, lung injury, and intracellular signaling pathway activation leading to lung inflammation, thus putting the NKA as a protagonist in lung injury pathology.

Exploring the Impact of Nanoparticle Stealth Coatings in Cancer Models: From PEGylation to Cell Membrane-Coating Nanotechnology

Nanotechnological platforms offer advantages over conventional therapeutic and diagnostic modalities. However, the efficient biointerfacing of nanomaterials for biomedical applications remains challenging. In recent years, nanoparticles (NPs) with different coatings have been developed to reduce nonspecific interactions, prolong circulation time, and improve therapeutic outcomes. This study aims to compare various NP coatings to enhance surface engineering for more effective nanomedicines. We prepared and characterized polystyrene NPs with different coatings of poly(ethylene glycol), bovine serum albumin, chitosan, and cell membranes from a human breast cancer cell line. The coating was found to affect the colloidal stability, adhesion, and elastic modulus of NPs. Protein corona formation and cellular uptake of NPs were also investigated, and a 3D tumor model was employed to provide a more realistic representation of the tumor microenvironment. The prepared NPs were found to reduce protein adsorption, and cell-membrane-coated NPs showed significantly higher cellular uptake. The secretion of proinflammatory cytokines in human monocytes after incubation with the prepared NPs was evaluated. Overall, the study demonstrates the importance of coatings in affecting the behavior and interaction of nanosystems with biological entities. The findings provide insight into bionano interactions and are important for the effective implementation of stealth surface engineering designs.

The Role of Cytokines in Activation of Tumour-promoting Pathways and Emergence of Cancer Drug Resistance

Scientists are constantly researching and launching potential chemotherapeutic agents as an irreplaceable weapon to fight the battle against cancer. Despite remarkable advancement over the past several decades to wipe out cancer through early diagnosis, proper prevention, and timely treatment, cancer is not ready to give up and leave the battleground. It continuously tries to find some other way to give a tough fight for its survival, either by escaping from the effect of chemotherapeutic drugs or utilising its own chemical messengers like cytokines to ensure resistance. Cytokines play a significant role in cancer cell growth and progression, and the present article highlights their substantial contribution to mechanisms of resistance toward therapeutic drugs. Multiple clinical studies have even described the importance of specific cytokines released from cancer cells as well as stromal cells in conferring resistance. Herein, we discuss the different mechanism behind drug resistance and the crosstalk between tumor development and cytokines release and their contribution to showing resistance towards chemotherapeutics. As a part of this review, different approaches to cytokines profile have been identified and employed to successfully target new evolving mechanisms of resistance and their possible treatment options.

Interleukin-6 and the determinants of severe COVID-19: A retrospective cohort study

Cytokines, notably interleukin-6 (IL-6), increase considerably in patients with severe corona virus disease 2019 (COVID-19). This vigorous immune response may cause end-organ failure or death; hence, measuring IL-6 in the context of patient characteristics may help predict outcomes and encourage early comprehensive therapy. This study investigated the association between serum IL-6 levels, COVID-19 severity, and demographic, clinical, and biochemical characteristics. COVID-19 inpatients in NMC hospitals were investigated between November 2020 and November 2021. Several patient variables related to serum IL-6 and COVID-19 severity have been examined. The study included 374 COVID-19 inpatients, 235 of whom had severe disease with a median age of 51. The elderly had an increased risk of severe COVID-19 (73.8%) compared with young adults (71%), with higher white blood cells, D-dimer, Lactate dehydrogenase, creatinine, ferritin, prothrombin time, Procalcitonin, and fibrinogen levels (P < .001). C-reactive protein, troponin, intensive care unit admission, disease severity score, and mortality were significantly associated with higher serum IL-6 levels (P = .05) in the univariate analysis, but this significance disappeared in the multivariate analysis. IL-6, along with other demographic and clinical variables affected COVID-19 severity. These characteristics may predict patients at risk of severe disease and assist in establishing early comprehensive disease outcome strategies. Large-scale clinical research is needed to emphasize IL-6 and COVID-19.

Cardiomyocytic cyclic GMP-AMP synthase is critical for the induction of experimental cardiac graft rejection

OBJECTIVE

During cardiac transplantation, cellular injury and DNA damage can result in the accumulation of cytosolic double-stranded DNA (dsDNA), which can activate the cyclic GMP-AMP synthase (cGAS)/stimulator of interferon gene (STING) signaling pathway and thus induce multiple proinflammatory responses. However, the role of the cGAS-STING pathway in cardiac transplantation remains unclear. This study explored the role of cardiomyocytic cGAS in mouse heart transplantation during the ischemia/reperfusion and rejection processes.

METHODS AND RESULTS

Cytosolic dsDNA accumulation and cGAS-STING signaling pathway component upregulation were observed in the grafts posttransplantation. The use of cGAS-deficient donor tissues led to significantly prolonged graft survival. The underlying mechanisms involved decreased expression and phosphorylation of downstream proteins, including TANK binding kinase 1 and nuclear factor κB. In parallel, notably diminished expression levels of various proinflammatory cytokines were observed. Accordingly, substantially decreased proportions of macrophages (CD11b+F4/80+) and CD8+ T cells were observed in the spleen. The activation of CD8+ T cells (CD8+CD69+) within the graft and the proportion of effector memory (CD44highCD62Llow) lymphocytes in the spleen were notably decreased. Treatment with the cGAS inhibitor Ru.521 led to significantly prolonged graft survival.

CONCLUSIONS

Cardiomyocytic cGAS plays a critical role by sensing cytosolic dsDNA during cardiac transplantation and could serve as a potential therapeutic target to prevent graft rejection.

Tocilizumab for antibody-mediated rejection treatment in lung transplantation

Tocilizumab (TCZ), an IL-6 inhibitor, has shown promise in the treatment of donor-specific antibodies (DSA) and chronic antibody-mediated rejection (AMR) in renal transplant recipients. However, its use in lung transplantation has not been described. This retrospective case-control study compared AMR treatments containing TCZ in 9 bilateral lung transplant recipients to 18 patients treated for AMR without TCZ. Treatment with TCZ resulted in more clearance of DSA, lower recurrence of DSA, lower incidence of new DSA, and lower rates of graft failure when compared to those treated for AMR without TCZ. The incidence of infusion reactions, elevation in transaminases, and infections were similar between the 2 groups. These data support a role for TCZ in pulmonary AMR and establish preliminary evidence to design a randomized controlled trial of IL-6 inhibition for the management of AMR.

Management of the sensitized heart transplant candidate

PURPOSE OF REVIEW

For sensitized heart transplant candidates who have antibodies to human leukocyte antigens (HLA), finding a suitable donor can be challenging and can lead to adverse waitlist outcomes. In recent years, the number of sensitized patients awaiting heart transplantation has increased likely due to the use of durable and mechanical circulatory support as well as increasing number of candidates with underlying congenital heart disease.

RECENT FINDINGS

Advances in the assessment of HLA antibodies allow for identification of heart transplant candidates who may benefit from desensitization strategies to widen the donor pool and mitigate the risk of adverse posttransplant outcomes.

SUMMARY

Antibody sensitization is a barrier to successful heart transplantation and strategies to identify sensitized patients, stratify their risk, and mitigate this risk through desensitization is crucial to optimize the quality of life and survival of HT recipients.

Unveiling the immunomodulatory shift: Epithelial-mesenchymal transition Alters immune mechanisms of amniotic epithelial cells

Epithelial-mesenchymal transition (EMT) changes cell phenotype by affecting immune properties of amniotic epithelial cells (AECs). The present study shows how the response to lipopolysaccharide of cells collected pre- (eAECs) and post-EMT (mAECs) induces changes in their transcriptomics profile. In fact, eAECs mainly upregulate genes involved in antigen-presenting response, whereas mAECs over-express soluble inflammatory mediator transcripts. Consistently, network analysis identifies CIITA and Nrf2 as main drivers of eAECs and mAECs immune response, respectively. As a consequence, the depletion of CIITA and Nrf2 impairs the ability of eAECs and mAECs to inhibit lymphocyte proliferation or macrophage-dependent IL-6 release, thus confirming their involvement in regulating immune response. Deciphering the mechanisms controlling the immune function of AECs pre- and post-EMT represents a step forward in understanding key physiological events wherein these cells are involved (pregnancy and labor). Moreover, controlling the immunomodulatory properties of eAECs and mAECs may be essential in developing potential strategies for regenerative medicine applications.

Downregulation of Swine Leukocyte Antigen Expression Decreases the Strength of Xenogeneic Immune Responses towards Renal Proximal Tubular Epithelial Cells

Xenotransplantation reemerged as a promising alternative to conventional transplantation enlarging the available organ pool. However, success of xenotransplantation depends on the design and selection of specific genetic modifications and on the development of robust assays allowing for a precise assessment of tissue-specific immune responses. Nevertheless, cell-based assays are often compromised by low proliferative capacity of primary cells. Proximal tubular epithelial cells (PTECs) play a crucial role in kidney function. Here, we generated immortalized PTECs (imPTECs) by overexpression of simian virus 40 T large antigen. ImPTECs not only showed typical morphology and phenotype, but, in contrast to primary PTECs, they maintained steady cell cycling rates and functionality. Furthermore, swine leukocyte antigen (SLA) class I and class II transcript levels were reduced by up to 85% after transduction with lentiviral vectors encoding for short hairpin RNAs targeting β2-microglobulin and the class II transactivator. This contributed to reducing xenogeneic T-cell cytotoxicity (p < 0.01) and decreasing secretion of pro-inflammatory cytokines such as IL-6 and IFN-γ. This study showed the feasibility of generating highly proliferative PTECs and the development of tissue-specific immunomonitoring assays. Silencing SLA expression on PTECs was demonstrated to be an effective strategy to prevent xenogeneic cellular immune responses and may strongly support graft survival after xenotransplantation.

Emerging Therapies for Antibody-Mediated Rejection in Kidney Transplantation

Despite the advances in immunosuppressive medications, antibody-mediated rejection (AMR) continues to be a major cause of kidney allograft failure and remains a barrier to improving long-term allograft survival. Recently, there have been significant advances in the understanding of the pathophysiological process of AMR, along with the development of new therapeutic options. Additionally, surveillance protocols with donor-derived cell-free DNA and gene profile testing have been established, leading to the early detection of AMR. A multitude of clinical trials are ongoing, opening numerous opportunities for improving outcome in kidney transplant recipients. In this brief review, we discuss the emerging therapies for managing both active and chronic active AMR and highlight the ongoing clinical trials.

Kidney Allograft Rejection and Coronavirus Disease 2019 Infection: A Narrative Review

The world has experienced a global medical and socioeconomic burden following the coronavirus disease 2019 (COVID-19) pandemic. COVID-19 is a systemic disease and may affect different organs including the kidneys. Current literature contains reports on COVID-19-related conditions such as acute kidney injury, and complications experienced by chronic kidney disease, end stage kidney disease, and kidney transplant patients. Here, we discuss the incidence of kidney allograft rejection, immunosuppression management and rejection risk, donor-specific antibodies and previous rejection episodes, and rejection outcomes in kidney transplant recipients with COVID-19 by reviewing current studies.

Anti-complement 5 antibody ameliorates antibody-mediated rejection after liver transplantation in rats

Antibody-mediated rejection (AMR) remains a refractory rejection after donor-specific antibody (DSA)-positive or blood-type incompatible liver transplantation (LT), even in the era of pre-transplant rituximab desensitization. This is due to the lack of not only effective post-transplant treatments but also robust animal models to develop/validate new interventions. Orthotopic LT from male Dark Agouti (DA) to male Lewis (LEW) rats was used to develop a rat LT-AMR model. LEW were pre-sensitized by a preceding skin transplantation from DA 4-6 weeks before LT (Group-PS), while sham procedure was performed in non-sensitized controls (Group-NS). Tacrolimus was daily administered until post-transplant day (PTD)-7 or sacrifice to suppress cellular rejections. Using this model, we validated the efficacy of anti-C5 antibody (Anti-C5) for LT-AMR. Group-PS+Anti-C5 received Anti-C5 intravenously on PTD-0 and -3. Group-PS showed increased anti-donor (DA) antibody-titers (P <0.001) and more C4d deposition in transplanted livers than in Group-NS (P <0.001). Alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bile acid (TBA), and total bilirubin (T-Bil) were all significantly higher in Group-PS than in Group-NS (all P <0.01). Thrombocytopenia (P <0.01), coagulopathies (PT-INR, P =0.04), and histopathological deterioration (C4d+h-score, P <0.001) were also confirmed in Group-PS. Anti-C5 administration significantly lowered anti-DA IgG (P <0.05), resulting in decreased ALP, TBA, and T-Bil on PTD-7 than in Group-PS (all P <0.01). Histopathological improvement was also confirmed on PTD-1, -3, and -7 (all P <0.001). Of the 9,543 genes analyzed by RNA sequencing, 575 genes were upregulated in LT-AMR (Group-PS vs. Group-NS). Of these, 6 were directly associated with the complement cascades. In particular, Ptx3, Tfpi2, and C1qtnf6 were specific to the classical pathway. Volcano plot analysis identified 22 genes that were downregulated by Anti-C5 treatment (Group-PS+Anti-C5 vs. Group-PS). Of these, Anti-C5 significantly down-regulated Nfkb2, Ripk2, Birc3, and Map3k1, the key genes that were amplified in LT-AMR. Notably, just two doses of Anti-C5 only on PTD-0 and -3 significantly improved biliary injury and liver fibrosis up to PTD-100, leading to better long-term animal survival (P =0.02). We newly developed a rat model of LT-AMR that meets all the Banff diagnostic criteria and demonstrated the efficacy of Anti-C5 antibody for LT-AMR.

Impact of Eucalyptus maculata Hook resin exudate constituents on reducing COX-2 gene expression: In-vivo anti-inflammatory, molecular docking and dynamics studies

ETHNOPHARMACOLOGICAL RELEVANCE

Eucalyptus maculata Hook from the Myrtaceae family is a native Australian plant that is frequently cultivated in Egypt. Many Eucalyptus species, including E. maculata, were widely used by the Dharawal, the indigenous Australian people, for their anti-inflammatory properties.

AIM OF THE STUDY

The purpose of this study was to determine the anti-inflammatory activity of the ethanol extract of E. maculata resin exudate, its methylene chloride and n-butanol fractions, as well as the isolated compounds.

MATERIALS AND METHODS

the ethanol extract was partitioned by methylene chloride, and n-butanol saturated with water. The fractions were chromatographed to isolate pure compounds. In-vivo anti-inflammatory activity of the ethanol extract, the fractions at a dose of 200 mg/Kg, and the isolated compounds (20 mg/Kg) was estimated using carrageenan-induced rat paws edema method against indomethacin (20 mg/Kg). The activity was supported by histopathological and biochemical parameters.

RESULTS

Three isolated compounds were identified as aromadendrin (C1), 7-O-methyl aromadendrin (C2), and naringenin (C3). Our findings demonstrated that the tested fractions significantly reduced the paw edema starting from the 3rd to the 5th hour as compared to the positive control, compounds C2 and C3 showed the greatest significant reduction in paw edema. The ethanol extract, fractions, C2, and C3 demonstrated an anti-inflammatory potential through reducing the levels of TNF-α, IL-6, and PGE2, as well as COX-2 protein expression compared to the negative control. These results were supported by molecular docking, which revealed that the isolated compounds had high affinity to target COX-1 and COX-2 active sites with docking scores ranging from -7.3 to -9.6 kcal mol^-1 when compared to ibubrofen (-7.8 and -7.4 kcal mol^-1, respectively). Molecular dynamics simulations were also performed and confirmed the docking results.

CONCLUSION

The results supported the traditional anti-inflammatory potency of E. maculata Hook, and the biochemical mechanisms underlying this activity were highlighted, opening up new paths for the development of potent herbal anti-inflammatory medicine. Finally, our findings revealed that E. maculata resin constituents could be considered as promising anti-inflammatory drug candidates.

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.

Detection and management of HLA sensitization in candidates for adult heart transplantation

Heart transplantation (HT) remains the preferred therapy for patients with advanced heart failure. However, for sensitized HT candidates who have antibodies to human leukocyte antigens , finding a suitable donor can be challenging and can lead to adverse waitlist outcomes. In recent years, the number of sensitized patients awaiting HT has increased likely due to the use of durable and mechanical circulatory support as well as increasing number of candidates with underlying congenital heart disease. This State-of-the-Art review discusses the assessment of human leukocyte antigens antibodies, potential desensitization strategies including mechanisms of action and specific protocols, the approach to a potential donor including the use of complement-dependent cytotoxicity, flow cytometry, and virtual crossmatches, and peritransplant induction management.

Low-dose nano-gel incorporated with bile acids enhanced pharmacology of surgical implants

Aim: Major challenges to islet transplantation in Type 1 diabetes include host-inflammation, which results in failure to maintain survival and functions of transplanted islets. Therefore, this study investigated the applications of encapsulating the bile acid ursodeoxycholic acid (UDCA) with transplanted islets within improved nano-gel systems for Type 1 diabetes treatment. Materials & methods: Islets were harvested from healthy mice, encapsulated using UDCA-nano gel and transplanted into the diabetic mice, while the control group was transplanted encapsulated islets without UDCA. The two groups' survival plot, blood glucose, and inflammation and bile acid profiles were analyzed. Results & conclusion: UDCA-nano gel enhanced survival, glycemia and normalized bile acids' profile, which suggests improved islets functions and potential adjunct treatment for insulin therapy.

Conventional and Novel Approaches to Immunosuppression in Lung Transplantation

Most therapeutic advances in immunosuppression have occurred over the past few decades. Although modern strategies have been effective in reducing acute cellular rejection, excess immunosuppression comes at the price of toxicity, opportunistic infection, and malignancy. As our understanding of the immune system and allograft rejection becomes more nuanced, there is an opportunity to evolve immunosuppression protocols to optimize longer term outcomes while mitigating the deleterious effects of traditional protocols.

Linear IgA bullous dermatosis and elevated bullous interleukin-6 levels: Responsive to treatment with Anti-IL-6 receptor monoclonals

Linear IgA bullous dermatosis (LABD) is  a rare autoimmune/inflammatory skin condition. Here, we report on a patient who developed treatment resistant LABD. At diagnosis, elevations of IL-6 and C-reactive protein in the blood and extreme elevations of IL-6 in LABD bullous fluid were seen. The patient responded well to tocilizumab (anti-IL-6 receptor) treatment.

Novel therapies for treatment of antibody-mediated rejection of the kidney

PURPOSE OF REVIEW

We aim to discuss current literature on novel therapies for antibody-mediated rejection (AMR) in kidney transplantation with a focus on chronic AMR.

RECENT FINDINGS

IL-6/IL-6 receptor blockers appear promising in the treatment of chronic AMR. Blocking this pathway was shown to reduce human leucocyte antigen-antibodies, improve histologic inflammation and increase T-regulatory cells. Based on experience in desensitization, IgG degrading endopeptidase, imlifidase, could be effective in AMR. There have been case reports describing the successful use of plasma cell/natural killer-cell-directed anti-CD38 antibody in the treatment of AMR. Off-target effects have been noted and strategies to mitigate these will be needed when using these agents. Complement inhibitors could be an effective add-on strategy to antibody-depleting therapies but their role in AMR needs to be better defined. Combining proteasome inhibitors and costimulation blockers has shown encouraging results in the prevention of AMR in animal models and is now being investigated in humans. Other novel strategies such as Fc neonatal receptor blockers which inhibit the recycling of pathogenic IgG and bispecific antibodies against B-cell maturation antigen/CD3+ T cells warrant further investigation.

SUMMARY

There are now a number of emerging therapies with varied targets and mechanism(s) of action that hold promise in the management of AMR and improving allograft survival.

Current Status of ABO-incompatible Liver Transplantation

By 2014, strategies to prevent antibody-mediated rejection (AMR) after ABO-incompatible (ABO-I) living donor liver transplantation (LDLT) were established in Japan and expanded primarily to Asia, where LDLT is now the predominant form of LT owing to the scarcity of brain-dead donors. A desensitization protocol consisting of rituximab (375 mg/m 2 ), plasma pheresis, tacrolimus, and mycophenolate mofetil before LDLT, followed by standard immunosuppression, is currently the best option in terms of safety and efficacy. Rituximab administration is now known not to increase the risk of hepatocellular carcinoma recurrence, and the feasibility of rituximab for LDLT for acute liver failure and the need for desensitization before LDLT in children older than 1 y have been documented. Strategies are needed to distinguish patients at high risk of AMR from those at low risk and to adjust immunosuppression to prevent both AMR and infection. Specific single-nucleotide polymorphisms in genes encoding Fcγ receptors affecting the cytotoxicity of rituximab on B cells could be useful for adjusting immunosuppression levels to decrease infectious complications. Immunological accommodation after ABO-I transplantation could be provided by immune factors in both the grafts and recipients.

Tocilizumab Evaluation in HLA-Desensitization before Kidney Transplantation as an Add-On Therapy to Apheresis: The TETRA Study

BACKGROUND

Desensitization strategies improve access to transplantation in highly sensitized kidney transplant candidates. Tocilizumab could be a valuable addition to more traditional desensitization regimens. We investigated the effect of tocilizumab as an add-on therapy to our standard of care (SoC) desensitization strategy based on rituximab and apheresis.

METHODS

In this study, we prospectively included highly sensitized patients to receive monthly tocilizumab infusions for 6 months before our SoC regimen (Toci + SoC group). We compared the reductions in the mean fluorescent intensity (MFI) rebound at post-transplantation and kidney function at 1-year post-transplantation to patients treated by SoC (based on apheresis and two doses of rituximab).

RESULTS

Twenty-six patients were included in the SoC group; seven in the Toci + SoC group. Reductions in pre-transplantation MFI were similar between groups. At 1-year post-transplantation, there was no absolute difference in overall MFI rebounds, including donor-specific antibodies. Toci + SoC helped lower the rebound of antibodies with more elevated baseline MFIs. Graft function and survival rates were similar at one-year post-transplantation (median eGFR 62.8 vs. 65.6 mL/min/1.73 m² for SoC and Toci + SoC, respectively).

CONCLUSIONS

Tocilizumab as an add-on to SoC desensitization may help control the post-transplantation rebound of antibodies with elevated baseline MFIs. However, reductions in pre-transplantation MFIs were similar with or without tocilizumab. Further studies are needed to validate this pilot study.

Endothelial progenitor cells in the host defense response

Extensive injury of endothelial cells in blood vasculature, especially in the microcirculatory system, frequently occurs in hosts suffering from sepsis and the accompanied systemic inflammation. Pathological factors, including toxic components derived from invading microbes, oxidative stress associated with tissue ischemia/reperfusion, and vessel active mediators generated during the inflammatory response, are known to play important roles in mediating endothelial injury. Collapse of microcirculation and tissue edema developed from the failure of endothelial barrier function in vital organ systems, including the lung, brain, and kidney, are detrimental, which often predict fatal outcomes. The host body possesses a substantial capacity for maintaining vascular homeostasis and repairing endothelial damage. Bone marrow and vascular wall niches house endothelial progenitor cells (EPCs). In response to septic challenges, EPCs in their niche environment are rapidly activated for proliferation and angiogenic differentiation. In the meantime, release of EPCs from their niches into the blood stream and homing of these vascular precursors to tissue sites of injury are markedly increased. The recruited EPCs actively participate in host defense against endothelial injury and repair of damage in blood vasculature via direct differentiation into endothelial cells for re-endothelialization as well as production of vessel active mediators to exert paracrine and autocrine effects on angiogenesis/vasculogenesis. In recent years, investigations on significance of EPCs in host defense and molecular signaling mechanisms underlying regulation of the EPC response have achieved substantial progress, which promotes exploration of vascular precursor cell-based approaches for effective prevention and treatment of sepsis-induced vascular injury as well as vital organ system failure.

Updated management for antibody-mediated rejection: opportunity to prolong kidney allograft survival

PURPOSE OF REVIEW

Antibody-mediated rejection (ABMR) is an important barrier to achieve long-term kidney allograft survival. Human leukocyte antibody (HLA)-incompatibility and ABO-incompatibility are the two main mechanisms of ABMR. Nevertheless, the advances in managing ABMR have changed the paradigm for kidney transplantation. This review aimed to emphasize the HLA-incompatibility and ABO-incompatibility kidney transplant and update the management of ABMR.

RECENT FINDINGS

HLA-incompatibility kidney transplantation is a strong risk factor for ABMR. Donor-specific antibody (DSA) is a surrogate biomarker that prevents long-term allograft survival. The standard treatment for ABMR has unfavorable results. New drugs that target the B cell are a promising approach to treat ABMR. In the past, ABO-incompatibility kidney donor was an absolute contraindication but now, it is widely accepted as an alternative organ resource. The advancement of ABO antibody removal and B-cell depletion therapy has been successfully developed. ABO isoagglutination remains the main biomarker for monitoring ABMR during the transplantation process. C4d staining without inflammation of the kidney allograft is the marker for the accommodation process.

SUMMARY

With the shortage of organ donors, transplant experts have expanded the organ resources and learned how to overcome the immunological barriers by using novel biomarkers and developing new treatments that support long-term graft survival.

Clazakizumab for the treatment of chronic active antibody-mediated rejection (AMR) in kidney transplant recipients: Phase 3 IMAGINE study rationale and design

BACKGROUND

Chronic active antibody-mediated rejection (AMR) is a major cause of graft loss with no approved drugs for its treatment. Currently, off-label regimens are used, reflecting the high unmet need for effective therapies based on well-controlled trials. Clazakizumab is a high-affinity, humanized monoclonal antibody that binds interleukin-6 and decreases donor-specific antibody (DSA) production and inflammation. Phase 2 pilot studies of clazakizumab in kidney transplant recipients with chronic active AMR suggest modulation of DSA, stabilization of glomerular filtration rate (GFR), and a manageable safety profile. We report the design of the Phase 3 IMAGINE study (NCT03744910) to evaluate the safety and efficacy of clazakizumab for the treatment of chronic active AMR.

METHODS

IMAGINE is a multicenter, double-blind trial of approximately 350 kidney transplant recipients with chronic active AMR (Banff chronic glomerulopathy [cg] >0 with concurrent positive human leukocyte antigen DSA) randomized 1:1 to receive clazakizumab or placebo (12.5 mg subcutaneous once every 4 weeks). The event-driven trial design will follow patients until 221 occurrences of all-cause graft loss are observed, defined as return to dialysis, graft nephrectomy, re-transplantation, estimated GFR (eGFR) <15 mL/min/1.73m², or death from any cause. A surrogate for graft loss (eGFR slope) will be assessed at 1 year based on prior modeling validation. Secondary endpoints will include measures of pharmacokinetics/pharmacodynamics. Recruitment is ongoing across North America, Europe, Asia, and Australia.

DISCUSSION

IMAGINE represents the first Phase 3 clinical trial investigating the safety and efficacy of clazakizumab in kidney transplant recipients with chronic active AMR, and the largest placebo-controlled trial in this patient population. This trial includes prognostic biomarker enrichment and uniquely utilizes the eGFR slope at 1 year as a surrogate endpoint for graft loss, which may accelerate the approval of a novel therapy for patients at risk of graft loss. The findings of this study will be fundamental in helping to address the unmet need for novel therapies for chronic active AMR.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03744910 . Registered on November 19, 2018.

Importance of IL-6 inhibition in prevention and treatment of antibody-mediated rejection in kidney allografts

Interleukin-6 (IL-6) is a cytokine critical for innate and adaptive immune responses. However, persistent expression of high levels of IL-6 are associated with a number of pathologic conditions including autoimmune diseases and capillary leak syndrome. Importantly, in kidney transplant patients, IL-6 may play a role in mediation of cell-mediated rejection (CMR) and antibody-mediated rejection (AMR). This is likely due to the importance of IL-6 in stimulating B cell responses with pathogenic donor-specific antibody (DSA) generation and stimulation of T effector cell responses while inhibiting T regulatory cells. Data from preliminary clinical trials and clinical observations show that tocilizumab (anti-IL-6R) and clazakizumab (anti-IL-6) may have promise in treatment of CMR, AMR and chronic (cAMR). This has led to a phase 3 placebo, randomized clinical trial of clazakizumab for treatment of cAMR, a condition for which there is currently no treatment. The identification of IL-6 production in vascular endothelia cells after alloimmune activation reveals another potential pathway for vasculitis as endothelia cell IL-6 may stimulate immune cell responses that are potentially inhibitable with anti-IL-6/IL-6R treatment. Importantly, anti-IL-6/IL-6R treatments have shown the ability to induce Treg and Breg cells in vivo which may have potential importance for prevention and treatment of DSA development and allograft rejection.

An interleukin 6-based genetic risk score strengthened with interleukin 10 polymorphisms associated with long-term kidney allograft outcomes

Of all kidney transplants, half are still lost in the first decade after transplantation. Here, using genetics, we probed whether interleukin 6 (IL-6) could be a target in kidney transplantation to improve graft survival. Additionally, we investigated if a genetic risk score (GRS) based on IL6 and IL10 variants could improve prognostication of graft loss. In a prospective cohort study, DNA of 1271 donor-recipient kidney transplant pairs was analyzed for the presence of IL6, IL6R, IL10, IL10RA, and IL10RB variants. These polymorphisms and their GRS were then associated with 15-year death-censored allograft survival. The C|C-genotype of the IL6 polymorphism in donor kidneys and the combined C|C-genotype in donor-recipient pairs were both associated with a reduced risk of graft loss (p = .043 and p = .042, respectively). Additionally, the GRS based on IL6, IL6R, IL10, IL10RA, and IL10RB variants was independently associated with the risk of graft loss (HR 1.53, 95%-CI [1.32-1.84]; p < .001). Notably, the GRS improved risk stratification and prediction of graft loss beyond the level of contemporary clinical markers. Our findings reveal the merits of a polygenic IL-6-based risk score strengthened with IL-10- polymorphisms for the prognostication and risk stratification of late graft failure in kidney transplantation.

Rationale for the IMAGINE study for chronic active antibody-mediated rejection (caAMR) in kidney transplantation

Chronic active antibody-mediated rejection (caAMR) in kidney transplantation is a major cause of late graft loss and despite all efforts to date, there is no proven effective therapy. Indeed, the Transplant Society (TTS) consensus opinion called for a conservative approach optimizing baseline immunosuppression and supportive care focused on blood pressure, blood glucose, and lipid control. This review provides the rationale and early evidence in kidney transplant recipients with caAMR that supported the design of the IMAGINE study whose goal is to evaluate the potential impact of targeting the IL6/IL6R pathway.

Intratesticular Versus Intrafunicular Lidocaine to Reduce Perioperative Nociception and Immunological Response in Ponies Undergoing Field Castration

The aim of this study was to evaluate the impact of intratesticular or intrafunicular lidocaine to reduce perioperative nociception and cytokine release in ponies undergoing field castration under total intravenous anaesthesia. Before castration, one group was injected with intrafunicular (FL) lidocaine and the other received intratesticular (TL) lidocaine. All ponies were premedicated with acepromazine (0.05 mg/kg) intramuscularly. Twenty minutes after the administration of acepromazine, xylazine (1 mg/kg) and butorphanol (0.02 mg/kg) were administered intravenously. Lidocaine 2% was given 1 mL/100 kg intrafunicularly in the FL groups or 2 mL/100 kg intratesticularly on each testicular side for TL. Surgery was performed by the same team of two experienced surgeons using Serra's emasculator and an open technique was used for all ponies in order to promote postoperative drainage. In this study, we focused on the plasmatic levels of TNF-α and IL-6. The results from this study showed a significant difference in plasmatic concentrations of TNF-α and IL-6 between the two different locoregional anaesthetic protocols. Taken together, the results suggest that the intrafunicular lidocaine locoregional anaesthesia could be a useful technique in the anaesthesia protocol for field pony castration.

Work-family enrichment: A potential buffer of inflammation among black adults?

Background

Inflammation plays a known role in the development of cardiovascular disease (CVD), the leading cause of death in the United States and a condition that disproportionately affects Blacks. Although social stressors are frequently studied, the role of positive experiences in inflammation and its potential for CVD remains understudied. To address this gap, we examined the relationship between work family enrichment and inflammation in a population-based sample of working adults.

Methods

Participants were 447 working adults from Refresher Cohort of the National Study of Midlife Development in the United States (MIDUS) and the oversample of Blacks from the Milwaukee, WI. Serum concentration of pro-inflammatory biomarkers (IL-6/sIL-6r; CPR; Fibrinogen) were obtained via blood draw. Family-to-work enrichment (FtoWE) and work-to-family enrichment (WtoFE) were each assessed with four established survey questions.

Results

Blacks had higher concentrations of IL-6, CRP and Fibrinogen, and lower levels of sIL-6r than whites. A significant inverse relationship was observed between WtoFE and systemic inflammation as well as WtoFE and serum IL-6 concentration.

Conclusions

Individuals who perceived a stronger enhancing effect from work onto family showed lower levels of systemic inflammation and decreased concentrations of the pro-inflammatory cytokine IL-6; highlighting the potential work-family enrichment or other positive experiences may have in buffering the negative cardiovascular effects of inflammation. However, variation between racial groups remain undetermined.

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Higher concentrations of pro-inflammatory biomarkers were seen among Blacks.

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Greater WFE conferred less systemic inflammation and lower concentrations of IL-6.

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Positive experiences from work to family may buffer inflammation, improving CVD risk.

Association between interleukin-6 and lower urinary tract symptoms of benign prostatic hyperplasia

OBJECTIVE

To evaluate the association between IL-6 in prostatic tissue/blood sample and BPH-LUTS, so as to preliminarily discover an indicator of inflammation that could show the severity of LUTS.

PATIENTS AND METHODS

The prostatic tissues and blood samples were collected from 56 patients who underwent transurethral plasmakinetic resection of the prostate (TUPKRP). The association between IL-6 detected on prostatic tissues/blood sample and LUTS parameters, including international prostate symptom score (IPSS), peak flow rate (Q_max) and urodynamic parameters were analyzed with SPSS version 18.0, and p-value <0.05 was chosen as the criterion for statistical significance.

RESULTS

The TPSA and prostate volume (PV) were found to be higher in the inflammation group (p=0.021, 0.036). There was a positive association between prostate tissue inflammation and LUTS ([IPSS, storage symptoms score (SSS), voiding symptoms score (VSS), p<0.05], [Q_max, p=0.025], [obstruction, p=0.027] and [AUR, p=0.018]). The level of serum IL-6 was significantly higher in inflammatory group (p=0.008). However, no differences were observed in different degrees of inflammation (p=0.393). The level of IL-6 in prostatic tissue significantly increased with the degree of inflammation (p<0.001), and the intensity of IL-6 expression was statistically correlative with the degree of inflammation (p<0.001). The IL-6 expression in prostatic tissue was statistically relevant with IPSS (p=0.018) and SSS (p=0.012).

CONCLUSION

IL-6 expression in prostatic tissue is associated with storage IPSS, suggesting chronic inflammation might contribute to storage LUTS.

Aesculetin exhibited anti-inflammatory activities through inhibiting NF-кB and MAPKs pathway in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Aesculetin (6,7-dihydroxy-2H-1-benzopyran-2-one) has been reported to exhibit potent anti-inflammatory property both in vitro and in vivo.

AIMS OF THIS STUDY

In this study, we evaluated the anti-inflammatory effect and investigated underlying molecular mechanisms of aesculetin in LPS-induced RAW264.7 macrophages and DSS-induced colitis.

MATERIALS AND METHODS

In this study, the production of NO, TNF-α, and IL-6 were measured to identify the aesculetin with potent anti-inflammatory effect. Then, the underlying anti-inflammatory mechanisms were explored by western blotting in LPS-induced cells. Next, we verify the anti-inflammatory potential of aesculetin in DSS-induced colitis in vivo. The clinical symptoms of colitis, including weight loss, DAI, colon length and MPO activity, and the secretion of TNF-α and IL-6 were evaluated. Finally, Western blot analysis was applied to further investigate underlying mechanism in DSS-induced colitis model.

RESULTS

Our studies showed that aesculetin exhibited anti-inflammatory potential by inhibiting NO, TNF-α, and IL-6 production and reducing iNOS and NLRP3 expression in LPS-induced RAW264.7 cells. Mechanically, we found that aesculetin significantly inhibited LPS-induced activation of NF-κB and MAPKs signaling pathways. In DSS-induced mouse model, the colitis-related symptoms were relieved by treatment with aesculetin. Besides, aesculetin also inhibited the secretion of TNF-α and IL-6, and the activation of NF-κB and MAPKs signaling pathways in DSS-induced colitis.

CONCLUSIONS

The anti-inflammatory effect of aesculetin was connected with its inhibition on the activation of NF-κB and MAPKs signaling pathways both in vitro and in vivo. Therefore, aesculetin was expected to be developed as an anti-inflammatory drug.

Role of the Immune System in Renal Transplantation, Types of Response, Technical Approaches and Current Challenges

Advances over the last decades have made renal transplantation an important therapy for patients with end-stage renal disease, as the incidences of acute rejection and short-term transplant loss have been significantly reduced. However, long-term transplant survival remains a challenge in the renal transplantation community. The main causes of long-term graft loss are acute and chronic rejection, as well as the complications related to immunosuppression therapy. In spite of the breakthroughs achieved in recent years, histology is the gold standard technique to confirm the activation of the immune system against the graft with all the ensuing problems that taking biopsies brings to immunosuppressed patients. For this reason, several assays have been developed to try to monitor the immune function, but they show serious constraints owing to the fact that they require substantial laboratory work, they are not clinically available and they provide controversial results, so the combination of multiple assays is often needed to obtain a reliable diagnosis. Thus, the aim of this review is to perform a retrospective study of the immune system in renal transplantation, with special emphasis on the cutting-edge technological developments for monitoring, classification and early detection of rejection episodes in order to contribute to a better adjustment of immunosuppressive therapies and, hence, to a more personalized medicine that improves the quality of life of patients.

Thalidomide modulates renal inflammation induced by brain death experimental model

BACKGROUND

Brain death (BD) is characterized by a complex inflammatory response, resulting in dysfunction of potentially transplantable organs. This process is modulated by cytokines, which amplify graft immunogenicity. We have investigated the inflammatory response in an animal model of BD and analyzed the effects of thalidomide, a drug with powerful immunomodulatory properties.

METHODS

BD was induced in male Lewis rats. We studied three groups: Control (sham-operated rats) (n = 6), BD (rats subjected to brain death) (n = 6) and BD + Thalid (BD rats treated with one dose of thalidomide (200 mg/Kg), administered by gavage) (n = 6). Six hours after BD, serum levels of urea and creatinine, as well as systemic and renal tissue protein levels of TNF-α and IL-6, were analyzed. We also determined the mRNA expression of ET-1, and macrophage infiltration by immunohistochemistry.

RESULTS

BD induced a striking inflammatory status, demonstrated by a significant increase of plasma cytokines: TNF-α (2.8 ± 4.3 pg/mL [BD] vs. 9.4 ± 2.8 pg/mL [Control]), and IL-6 (6219.5 ± 1380.6 pg/mL [BD] vs. 1854.7 ± 822.6 pg/mL [Control]), and in the renal tissue: TNF-α (2.5 ± 0.3 relative expression [BD] vs. 1.0 ± 0.4 relative expression [Control]; p < 0.05), and IL-6 (4.0 ± 0.4 relative expression [BD] vs. 1.0 ± 0.3 relative expression [Control]; p < 0.05). Moreover, BD increased macrophages infiltration (2.47 ± 0.07 cells/field [BD] vs. 1.20 ± 0.05 cells/field [Control]; p < 0.05), and ET-1 gene expression (2.5 ± 0.3 relative expression [BD] vs. 1.0 ± 0.2 relative expression [Control]; p < 0.05). In addition, we have observed deterioration in renal function, characterized by an increase of urea (194.7 ± 25.0 mg/dL [BD] vs. 108.0 ± 14.2 mg/dL [Control]; p < 0.05) and creatinine (1.4 ± 0.04 mg/dL [BD] vs. 1.0 ± 0.07 mg/dL [Control]; p < 0.05) levels. Thalidomide administration significantly reduced plasma cytokines: TNF-α (5.1 ± 1.4 pg/mL [BD + Thalid] vs. BD; p < 0.05), and IL-6 (1056.5 ± 488.3 pg/mL [BD + Thalid] vs. BD; p < 0.05), as well as in the renal tissue: TNF-α (1.5 ± 0.2 relative expression [BD + Thalid] vs. BD; p < 0.05), and IL-6 (2.1 ± 0.3 relative expression [BD + Thalid] vs. BD; p < 0.05). Thalidomide treatment also induced a significant decrease in the expression of ET-1 (1.4 ± 0.3 relative expression [BD + Thalid] vs. BD; p < 0.05), and macrophages infiltration (1.17 ± 0.06 cells/field [BD + Thalid] vs. BD; p < 0.05). Also thalidomide prevented kidney function failure by reduced urea (148.3 ± 4.4 mg/dL [BD + Thalid] vs. BD; p < 0.05), and creatinine (1.1 ± 0.14 mg/dL [BD + Thalid] vs. BD; p < 0.05).

CONCLUSIONS

The immunomodulatory properties of thalidomide were effective in decreasing systemic and local immunologic response, leading to diminished renal damage, as reflected in the decrease of urea and creatinine levels. These results suggest that use of thalidomide may represent a potential strategy for treating in BD kidney organ donors.

Circulating biomarkers of response to immunotherapy and immune-related adverse events

INTRODUCTION

Immune checkpoint blockade has revolutionized cancer treatment. However, response rates vary, and these treatments have a high rate of immune-related side effects, which can be limiting. Thus, tests to predict who will respond and who may experience side effects are of critical importance toward realizing the ultimate goal of precision oncology.

AREAS COVERED

We review several of the most recent advances in circulating biomarkers that have been reported to be useful in predicting response and immune-related adverse events (irAE) to checkpoint blockade immunotherapies (CBI). We focus on high-quality studies published within the last few years. We highlight significant findings, identify areas for improvement, and provide recommendations on how these biomarkers may be translated into clinical utility.

EXPERT OPINION

As newer immunotherapies are developed, there is a pressing need to identify circulating biomarkers that can help predict responses and side effects. Current studies are mostly small-scale and retrospective; there is a need for larger-scale and prospective studies to help validate several of the biomarkers detailed here. As oncology focuses more on precision-based approaches, it is likely that a combination of biomarkers, including circulating ones as detailed here, will have critical utility in guiding clinical decisions.

Tocilizumab in the treatment of active chronic humoral rejection resistant to standard therapy

INTRODUCTION

There is no consensus on the most appropriate treatment for chronic active antibody-mediated rejection (cAMR). Recent studies suggest that treatment with tocilizumab (TCZ) may stabilize graft function, decrease the intensity of donor-specific HLA antibodies (DSAs) and reduce inflammation of microcirculation.

PATIENTS AND METHODS

Observational study with renal allograft recipients diagnosed with cAMR (n = 5) who had not submitted a response to traditional treatment based on the combination of plasma replacements, immunoglobulins, and rituximab. Patients were told to be treated with TCZ as compassionate use in six doses per month (8 mg/kg/month). Renal function, proteinuria, and the intensity of DSAs were monitored during follow-up.

RESULTS

Five patients, average age 60 ± 13 years, three male and two retrasplants (cPRA average 55%) with preformed DSAs. Treatment with TCZ was initiated within 47 ± 52 days of biopsy. In two cases treatment was discontinued after the first dose, by severe bicitopenia with cytomegalovirus viremia and by graft failure, respectively. In the three patients who completed treatment, no stability of renal function (serum creatinine from 1.73 ± 0.70 to 2.04 ± 0.52 mg/dL, e-FGR 4 6 ± 15 to 36 ± 16 mL/min), showed increased proteinuria (3.2 ± 4.0 to 6.9 ± 11.0 g/g) and the intensity of DSAs maintain stable. No changes were observed in the degree of inflammation of microcirculation (g+pt 4.2 ± 0.8 vs. 4.3 ± 1.0) or in the degree of transplant glomerulopathy (cg 1.2 ± 0.4 vs. 1.8 ± 1.0).

CONCLUSIONS

TCZ therapy does not appear to be effective in modifying the natural history of chronic active antibody-mediated rejection, does not improve the degree of inflammation of microcirculation and does not reduces the intensity of DSAs.

Donor and Recipient Adipose-Derived Mesenchymal Stem Cell Therapy for Rat Lung Transplantation

BACKGROUND

Mesenchymal stem cells (MSCs) are beginning to be proven as immunosuppressant in the field of organ transplantation. However, the effects of MSC origin (donor or recipient) on immunosuppression are not clear. Hence, we investigated the effects of recipient and donor adipose-derived MSCs (ADMSCs) on immunosuppression in a rat lung transplantation model.

METHODS

Subjects were divided into no treatment, tacrolimus administration, recipient ADMSC administration, donor ADMSC administration, and mixed donor and recipient ADMSC administration groups. ADMSC-administered groups were also treated with tacrolimus. Histologic study, immunofluorescence, immunohistochemistry, enzyme-linked immunosorbent assay, and polymerase chain reaction were used for various analyses.

RESULTS

Fluorescently labeled ADMSCs were predominant in the grafted donor lung, but not in the recipient lung, on day 5. On day 7, the pathologic rejection grades of the grafted donor lung were significantly lower in the ADMSC-administered groups (P < .05) and did not differ among these groups. Although serum hepatocyte growth factor and vascular endothelial growth factor levels did not differ among the groups, interleukin 10 level was slightly higher in the ADMSC-administered groups. The numbers of infiltrating regulatory T cells in the grafted lung were significantly higher in the ADMSC-administered groups (P < .05) but did not differ with cell origin. Transcriptional analysis suggested interleukin 6 suppression to be the main overlapping immunosuppressive mechanism, regardless of origin. Therefore, a donor or recipient origin may not influence the immunosuppressive efficacy of ADMSCs in our rat lung transplantation model.

CONCLUSIONS

Collectively, the results indicate that allogenic ADMSCs, regardless of their origin, may exert similar immunosuppressive effects in clinical organ transplantation.