ABSTRACT
AEB071 (AEB, sotrastaurin), a specific inhibitor of protein kinase C, reduces T-lymphocyte activation and cytokine release. AEB delays islet allograft rejection in rats and prevents rejection when combined with cyclosporine. Since many immunosuppressive agents have toxic effects on the function of transplanted islets, we investigated whether this was also the case with AEB. Human islets were transplanted into Rag-knockout mice randomly assigned to vehicle control, AEB or sirolimus treatment groups. Non-fasting blood glucose levels, body weight and glucose tolerance was measured in recipients. In a separate experiment, human islets were cultured in the presence of AEB and assayed for glucose dependent insulin secretion and level of ß-cell apoptosis. Eighty-six percent of the AEB-treated recipients achieved normoglycemia following transplant (compared with none in sirolimus-treated group, p < 0.05). AEB-treated recipients exhibited similar glucose homeostasis as vehicle-treated controls, which was better than in sirolimus-treated recipients. Human islets cultured with AEB showed similar rates of ß-cell apoptosis (p = 0.98 by one-way ANOVA) and glucose stimulated insulin secretion (p = 0.15) as those cultured with vehicle. These results suggest that AEB is not associated with toxic effects on islet engraftment or function. AEB appears to be an appropriate immunosuppressive candidate for clinical trials in islet transplantation.
Subject(s)
Apoptosis/drug effects , Islets of Langerhans Transplantation/methods , Islets of Langerhans/drug effects , Protein Kinase Inhibitors/pharmacology , Pyrroles/pharmacology , Quinazolines/pharmacology , Animals , Blood Glucose/metabolism , Body Weight/drug effects , Female , Glucose Tolerance Test , Humans , Immunohistochemistry , In Situ Nick-End Labeling , Insulin/metabolism , Insulin Secretion , Kaplan-Meier Estimate , Mice , Mice, Inbred C57BL , Mice, Knockout , Protein Kinase Inhibitors/toxicity , Pyrroles/toxicity , Quinazolines/toxicity , Random AllocationABSTRACT
BACKGROUND: Prosthetic mesh is used frequently in abdominal wall hernia reconstruction but is prone to postoperative adhesion formation. Complications resulting from intra-abdominal adhesions represent a considerable clinical and cost burden. We, herein, investigate the antiproliferative and antiadhesiogenic properties of sirolimus and hydrogel-impregnated, drug-eluting mesh to decrease such complications in a mouse model of abdominal wall hernia repair. METHODS: A 1 × 1cm(2) polypropylene mesh from 1 of 3 groups (group 1, plain control; group 2, hydrogel [2% agarose]; and group 3, hydrogel + 10 mcg sirolimus) was implanted operatively into the peritoneal cavity of BALB/c mice and followed for up to 4 weeks. Adhesions were scored by percent surface area of mesh (range, 0-100%), severity (range, 0-3), and tenacity (range, 0-4). Representative samples were assessed by scanning electron microscopy. RESULTS: Mesh impregnated with the combination of hydrogel and sirolimus led to a significant decrease in adhesion formation. The percent surface area of adhesional attachment to mesh was decreased from 100.0 ± 0% in the plain mesh control group versus 18 ± 8% (P < .001) in the combined impregnated mesh group. Similarly, adhesion severity scores were decreased from a score of 2.9 ± 0.1 (plain mesh) versus 1.4 ± 0.1 (sirolimus/hydrogel-impregnated mesh) (P < .001). Scores for tenacity were also decreased markedly from 3.5 ± 0.2 (plain mesh) versus 1.5 ± 0.1 (sirolimus/hydrogel-impregnated mesh (P < .001). CONCLUSION: Creation of a sirolimus drug-eluting and hydrogel-impregnated polypropylene mesh resulted in marked decrease of adhesion formation in this mouse model, was well tolerated without side effects, and has potential for clinical application.
Subject(s)
Abdominal Wall/surgery , Abdominal Wound Closure Techniques/instrumentation , Hernia, Abdominal/surgery , Sirolimus/pharmacology , Surgical Mesh , Tissue Adhesions/prevention & control , Animals , Biocompatible Materials/pharmacology , Disease Models, Animal , Hydrogel, Polyethylene Glycol Dimethacrylate , Immunosuppressive Agents/pharmacology , Male , Mice , Mice, Inbred BALB C , Microscopy, Electron, Scanning , PolypropylenesABSTRACT
BACKGROUND: AEB-071 (AEB) is a specific inhibitor of protein kinase C, which prevents T-lymphocyte activation. The present study investigated the effect of AEB on rat islet allotransplantation alone or in combination with CTLA4-Ig, mycophenolate mofetil, or cyclosporine A (CsA). METHODS: A rodent allogeneic islet transplant model (Lewis to Wistar Furth) was used to investigate the efficacy of AEB as an immunosuppressive agent. Furthermore, the Lewis rat was used to screen for any AEB associated toxicities on glucose homeostasis in vivo. RESULTS: AEB alone (30 mg/kg per os [p.o.] two times per day [bid]) delayed rejection to a median survival time of 22 days (vs. 7 days in control vehicle-treated animals, P<0.05). When combined with CsA (5 mg/kg p.o. bid), AEB prolonged survival from 12 (CsA alone) to over 100 days in 80% of animals (P<0.05). No delay in allograft rejection (above that resulting from AEB alone) was observed when AEB was combined with a sub-therapeutic dose of CTLA4-Ig or mycophenolate mofetil, nor low dose of CsA. The frequency of allospecific interferon-gamma-secreting splenocytes, assessed ex vivo by enzyme-linked immunosorbent spot (ELISPOT) assay, was lower in AEB-treated recipients compared with controls (P<0.05). AEB treatment did not alter the intraperitoneal glucose tolerance, the glucose-dependent insulin release, or the insulin content of the native pancreas. CONCLUSIONS: These data suggest that AEB is an appropriate immunosuppressive agent for islet transplantation, as it can prolong islet graft survival alone or in combination with CsA, without toxicity on glucose metabolism.
