Gumpei Yoshimatsu

A small molecule inhibitor of NFκB blocks ER stress and the NLRP3 inflammasome and prevents progression of pancreatitis

BackgroundThe underlying molecular mechanism that leads to development of chronic pancreatitis remains elusive. The aim of this study is to understand the downstream inflammatory signaling involved in progression of chronic pancreatitis, and to use withaferin A (WA), a small molecule inhibitor of nuclear factor κB (NFκB), to prevent progression of chronic pancreatitis.MethodsTwo different protocols were used to induce pancreatitis in mice: standard and stringent administration of cerulein. The severity of pancreatitis was assessed by means of pancreatic histology and serum amylase levels. Immunohistochemistry and flow-cytometric analysis was performed to visualize immune cell infiltration into the pancreas. Real-time PCR and Western blot were used to analyze the downstream signaling mechanism involved in the development of chronic pancreatitis.ResultsThe severity of cerulein-induced pancreatitis was reduced significantly by WA, used as either preventive or curative treatment. Immune cell infiltration into the pancreas and acinar cell death were efficiently reduced by WA treatment. Expression of proinflammatory and proapoptotic genes regulated by NFκB activation was increased by cerulein treatment, and WA suppressed these genes significantly. Sustained endoplasmic reticulum stress activation by cerulein administration was reduced. NLRP3 inflammasome activation in cerulein-induced pancreatitis was identified, and this was also potently blocked by WA. The human pancreatitis tissue gene signature correlated with the mouse model.ConclusionsOur data provide evidence for the role of NFκB in the pathogenesis of chronic pancreatitis, and strongly suggest that WA could be used as a potential therapeutic drug to alleviate some forms of chronic pancreatitis.

Clinical effectiveness of a pylorus-preserving procedure on total pancreatectomy with islet autotransplantation.

BACKGROUND The impact of pylorus preserving procedures (PP) on total pancreatectomy with islet autotransplantation (TPIAT) has not been examined. This study aimed to investigate the clinical impact of the PP on TPIAT. METHODS The Baylor Simmons Transplant Institute database was queried to identify seventy-three patients who underwent TPIAT from 2006 to 2014. All patients were investigated in postoperative complications, long-term nutritional status, and graft function. RESULTS Patients with PP did not face worse outcomes in terms of delayed gastric emptying and length of hospital stay. Also, nutritional status and metabolic outcome, such as body weight, serum albumin level, serum vitamin level, HbA1c level, graft survival rate and insulin independent rate, were similar between both groups. CONCLUSIONS Clinical results including the graft function indicated that patients undergoing TPIAT with PP did not amplify surgical complications such as delayed gastric emptying and showed no significant advantage of nutrition and metabolic outcome.

MiR‐375 and miR‐200c as predictive biomarkers of islet isolation and transplantation in total pancreatectomy with islet autotransplantation

Total pancreatectomy with islet autotransplantation (TPIAT) is a promising treatment for refractory chronic pancreatitis. Predictable biomarkers for the endocrine function after transplantation would be helpful in selecting patients for TPIAT. This study aims to identify novel biomarkers for predicting the outcome of islet isolation and transplantation in TPIAT patients.

Islet damage during isolation as assessed by miRNAs and the correlation of miRNA levels with posttransplantation outcome in islet autotransplantation

High‐quality pancreatic islets are essential for better posttransplantation endocrine function in total pancreatectomy with islet autotransplantation (TPIAT), yet stress during the isolation process affects quality and yield. We analyzed islet‐enriched microRNAs (miRNAs) ‐375 and ‐200c released during isolation to assess damage and correlated the data with posttransplantation endocrine function. The absolute concentration of miR‐375, miR‐200c, and C‐peptide was measured in various islet isolation steps, including digestion, dilution, recombination, purification, and bagging, in 12 cases of TPIAT. Posttransplantation glycemic control was monitored through C‐peptide, hemoglobin A1c, insulin requirement, and SUITO index. The amount of miR‐375 released was significantly higher during enzymatic digestion followed by the islet bagging (P < .001). Mir‐200c mirrored these changes, albeit at lower concentrations. In contrast, the C‐peptide amount was significantly higher in the purification and bagging steps (P < .001). Lower amounts of miR‐375 were associated with a lower 6‐month insulin requirement (P = .01) and lower hemoglobin A1c (P = .04). Measurement of the absolute quantity of miRNA‐375 and ‐200c released during islet isolation is a useful tool to assess islet damage. The quantity of released miRNA is indicative of posttransplantation endocrine function in TPIAT patients.

Pancreatic Beta Cell-derived IP-10/CXCL10 Isletokine Mediates Early Loss of Graft Function in Islet Cell Transplantation.

Pancreatic islets produce and secrete cytokines and chemokines in response to inflammatory and metabolic stress. The physiological role of these “isletokines” in health and disease is largely unknown. We observed that islets release multiple inflammatory mediators in patients undergoing islet transplants within hours of infusion. The proinflammatory cytokine interferon-γ–induced protein 10 (IP-10/CXCL10) was among the highest released, and high levels correlated with poor islet transplant outcomes. Transgenic mouse studies confirmed that donor islet–specific expression of IP-10 contributed to islet inflammation and loss of β-cell function in islet grafts. The effects of islet-derived IP-10 could be blocked by treatment of donor islets and recipient mice with anti–IP-10 neutralizing monoclonal antibody. In vitro studies showed induction of the IP-10 gene was mediated by calcineurin-dependent NFAT signaling in pancreatic β-cells in response to oxidative or inflammatory stress. Sustained association of NFAT and p300 histone acetyltransferase with the IP-10 gene required p38 and c-Jun N-terminal kinase mitogen-activated protein kinase (MAPK) activity, which differentially regulated IP-10 expression and subsequent protein release. Overall, these findings elucidate an NFAT-MAPK signaling paradigm for induction of isletokine expression in β-cells and reveal IP-10 as a primary therapeutic target to prevent β-cell–induced inflammatory loss of graft function after islet cell transplantation.

The impact of allogenic blood transfusion on the outcomes of total pancreatectomy with islet autotransplantation

BACKGROUND Allogenic blood transfusion (ABT) may be needed for severe bleeding during total pancreatectomy with autotransplantation (TPIAT), but may induce inflammation. This study investigated the impact of ABT. METHODS With a population of 83 patients who underwent TPIAT from 2006 to 2014, this study compared cytokine levels, patient characteristics, islet characteristics, metabolic outcomes, insulin requirements, and hemoglobin A1c for those who received a blood transfusion (BT) versus no blood transfusion (NBT). RESULTS Initially, proinflammatory cytokines were moderately higher in the BT group than the NBT group. Despite longer procedures and more severe bleeding, the BT group had similar values to the NBT group for insulin requirements, serum C-peptide, hemoglobin A1c, and insulin independence rate. The probability of insulin independence was slightly higher in patients receiving ≥3 units of blood. CONCLUSION ABT induced elevation of proinflammatory cytokines during the perioperative period in TPIAT, but these changes did not significantly change posttransplant islet function.

Ex-vivo generation of drug-eluting islets improves transplant outcomes by inhibiting TLR4-Mediated NFkB upregulation

The systemic administration of immunosuppressive and anti-inflammatory drugs is routinely employed in organ transplantation to minimize graft rejection and improve graft survival. Localized drug delivery has the potential to improve transplant outcomes by providing sustained exposure to efficacious drug concentrations while avoiding systemic immunosuppression and off-target effects. Here, we describe the synthesis of a novel prodrug and its direct covalent conjugation to pancreatic islets via a cleavable linker. Post-transplant, linker hydrolysis results in the release of a potent anti-inflammatory antagonist of TLR4, localized to the site of implantation. This covalent islet modification significantly reduces the time and the minimal effective dose of islets necessary to achieve normoglycemia in a murine transplantation model. In streptozotocin-induced diabetic C57BL/6 mice a syngeneic transplant of ∼100 modified islets achieved a 100% cure rate by the end of a 4-week monitoring period, compared to a 0% cure rate for untreated control islets. Overall, this direct prodrug conjugation to islets is well tolerated and preserves their functionality while affording significantly superior transplant outcomes. The development of drug-eluting tissues that deliver sustained and localized doses of small-molecule therapeutics represents a novel pathway for enhancing success in transplantation.

Risk factors for early readmission after total pancreatectomy and islet auto transplantation

BACKGROUND Little published data exist examining causes of hospital readmission following total pancreatectomy with islet autotransplantation (TPIAT). METHODS A retrospective analysis was performed of a prospectively collected institutional TPIAT database. Primary outcome was unplanned readmission to the hospital within 30 days from discharge. Reasons and risk factors for readmission as well as islet function were evaluated and compared by univariate and multivariate analysis. RESULTS 83 patients underwent TPIAT from 2006 to 2014. 21 patients (25.3%) were readmitted within 30 days. Gastrointestinal problems (52.4%) and surgical site infection (42.8%) were the most common reasons for readmission. Initial LOS and reoperation were risk factors for early readmission. Patients with delayed gastric emptying (DGE) were three times more likely to get readmitted. In multivariate analysis, patients undergoing pylorus preservation surgery were nine times more likely to be readmitted than the antrectomy group. CONCLUSION Early readmission after TPIAT is common (one in four patients), underscoring the complexity of this procedure. Early readmission is not detrimental to islet graft function. Patients undergoing pylorus preservation are more likely to get readmitted, perhaps due to increased incidence of delayed gastric emptying. Decision for antrectomy vs. pylorus preservation needs to be individualized.