Pancreatic islet transplantation (PITx) is an attractive treatment option for restoring appropriate glucose homeostasis in type 1 diabetes patients. Although islet grafts can successfully engraft after PITx, large numbers of islet grafts are required mainly because immune reactions, including inflammation, destroy islet grafts. In these processes, nuclear factor (NF)-κB plays a central role. We hypothesized that the inhibition of NF-κB activation would ameliorate inflammatory responses after PITx and aid successful engraftment. To test this hypothesis, a newly developed NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), was used on a syngeneic mouse PITx model. One hundred seventy-five islets from C57BL/6 (B6) mice were transplanted into streptozotocin-induced diabetic B6 mice. The recipient mice were administered DHMEQ for 1, 2, or 3 days after PITx. The underlying mechanisms of DHMEQ on islet graft protection were investigated in an in vitro coculture model of pancreatic islets and macrophages. With a vehicle treatment, only 11.1% of the islet-recipients achieved normoglycemia after PITx. In sharp contrast, DHMEQ treatment markedly improved the normoglycemic rate, which was associated with the suppression of serum high mobility group complex-1 (HMGB1) and proinflammatory cytokines, including tumor necrosis factor-α, monocyte chemoattractant protein-1, macrophage inflammatory protein-1β, interleukin-1β, and interleukin-6, after PITx. In a murine macrophage-like cell line, DHMEQ inhibited HMGB1-driven activation and proinflammatory cytokine secretion and further prevented death isolated islets after coculture with these activated macrophages. Inhibition of NF-κB activation by DHMEQ after PITx reduces the HMGB1-triggered proinflammatory responses and results in engraftment of transplanted islets even with fewer islet grafts.

Background Long-term graft deterioration remains a major obstacle in the success of pancreatic islet transplantation (PITx). Antigen-independent inflammatory and innate immune responses strengthen subsequent antigen-dependent immunity; further, activation of nuclear factor (NF)-κB plays a key role during these responses. In this study, we tested our hypothesis that, by the inhibition of NF-κB activation, the suppression of these early responses after PITx could facilitate graft acceptance. Methods Full major histocompatibility complex (MHC)–mismatched BALB/c (H-2^d) mice islets were transplanted into streptozotocin-induced diabetic C57BL/6 (B6: H-2^b) mice. The NF-κB inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) was administered for either 3 or 14 days after PITx. To some PITx recipients, tacrolimus was also administered. Islet allograft survival, alloimmune responses, and in vitro effects of DHMEQ on dendritic cells (DCs) were assessed. Results With a vehicle treatment, 600 islet allografts were promptly rejected after PITx. In contrast, 3-day treatment with DHMEQ, followed by 2-week treatment with tacrolimus, allowed permanent acceptance of islet allografts. The endogenous danger-signaling molecule high mobility group complex 1 (HMGB1) was elevated in sera shortly after PITx, whereas DHMEQ administration abolished this elevation. DHMEQ suppressed HMGB1-driven cellular activation and proinflammatory cytokine secretion in mouse bone marrow–derived DCs and significantly reduced the capacity of DCs to prime allogeneic T-cell proliferation in vitro. Finally, the DHMEQ plus tacrolimus regimen reverted the diabetic state with only 300 islet allografts. Conclusions Inhibition of NF-κB activation by DHMEQ shortly after PITx suppresses HMGB1, which activates DCs and strengthens the magnitude of alloimmune responses; this permits long-term islet allograft acceptance, even in case of fewer islet allografts.

Purpose: Active hexose-correlated compound (AHCC), a standardized extract of cultured Lentinula edodes mycelia, exerts antitumor effects through anti-inflammatory and immune-modulatory functions. Adjuvant therapy for patients with hepatocellular carcinoma (HCC) who have undergone curative hepatectomy has not been established. The purpose of this study was to evaluate the efficacy and safety of AHCC as adjuvant therapy in patients with advanced HCC after curative hepatectomy. Patients and methods: The study design was single-armed, non-randomized, open (no one was blinded), and uncontrolled. Patients with HCC who underwent curative hepatectomy were treated with AHCC (1 g) 3 times daily orally for 2 years. The inclusion criteria were HCC diagnosed preoperatively as stages A and B of the Barcelona clinic liver cancer (BCLC) classification and alpha-fetoprotein × protein induced by vitamin K absence or antagonist II (PIVKA-II) ≥ 10⁵ for stage A. Results: A total of 29 patients were treated with AHCC, of which 25 (4 patients discontinued) were followed up. The 2-year recurrence-free survival rate after resection was 48% for those without discontinuations and 55.2% for all patients with a history of treatment. Serum albumin levels decreased to a minimum in the first postoperative month and gradually recovered to the preoperative level at 6 months. Almost no change in lymphocyte percentage was observed during follow-up. Inflammation-based prognostic scores were maintained at favorable levels after hepatectomy. Toxicity and adverse events were not observed in any patient. Conclusion: AHCC may be safe and effective in preventing HCC recurrence after curative hepatectomy, and further randomized trials of AHCC for its use in this setting are warranted. This clinical trial was registered in UMIN Clinical Trials Registry (ID UMIN000024396).