Effect of Conversion to CTLA4Ig Treatment on Tacrolimus-Induced Diabetic Rats

ABSTRACTBackgroundThe effect of conversion to cytotoxic T-lymphocyte-associated protein 4 immunoglobulin (CTLA4Ig) treatment on tacrolimus (TAC)-induced renal dysfunction is well known, but its effect on TAC-induced diabetes mellitus (DM) is still undetermined. In the present study, we tested the diabetogenicity of CTLA4Ig and evaluated the effect of conversion to CTLA4Ig treatment on TAC-induced diabetic rats.MethodsWe tested diabetogenicity of CTLA4Ig by escalating doses (0.25, 0.5, 1, 2, and 4 mg/kg weekly) for 4 weeks. In the conversion study, we administered TAC (1.5 mg/kg) for 3 weeks and confirmed TAC-induced DM by intraperitoneal glucose tolerance test (IPGTT). Thereafter, TAC administration was continued, withdrawn, or replaced by CTLA4Ig treatment (1 or 2 mg/kg) for additional 3 weeks. The effect of CTLA4Ig on TAC-induced DM in vivo and in vitro was evaluated by assessing pancreatic islet function, histopathology, oxidative stress, apoptosis, and macrophage infiltration.ResultsIPGTT in the CTLA4Ig groups did not differ from the control group. In addition, plasma insulin level, glucose-induced insulin secretion, and islet viability were not different between the CTLA4Ig and control groups. In the conversion study, TAC withdrawal ameliorated pancreatic islet dysfunction compared to the TAC group, and conversion to CTLA4Ig further improved pancreatic islet function compared to the TAC withdrawal group. TAC-induced oxidative stress, apoptotic cell death, and infiltration of macrophages decreased with TAC withdrawal, and CTLA4Ig conversion further reduced those values. In the in vitro study, CTLA4Ig decreased TAC-induced pancreatic islet cell death and ROS production.ConclusionsCTLA4Ig was not diabetogenic, and conversion to CTLA4Ig reduced TAC-induced pancreatic islet injury. Background The effect of conversion to cytotoxic T-lymphocyte-associated protein 4 immunoglobulin (CTLA4Ig) treatment on tacrolimus (TAC)-induced renal dysfunction is well known, but its effect on TAC-induced diabetes mellitus (DM) is still undetermined. In the present study, we tested the diabetogenicity of CTLA4Ig and evaluated the effect of conversion to CTLA4Ig treatment on TAC-induced diabetic rats. Methods We tested diabetogenicity of CTLA4Ig by escalating doses (0.25, 0.5, 1, 2, and 4 mg/kg weekly) for 4 weeks. In the conversion study, we administered TAC (1.5 mg/kg) for 3 weeks and confirmed TAC-induced DM by intraperitoneal glucose tolerance test (IPGTT). Thereafter, TAC administration was continued, withdrawn, or replaced by CTLA4Ig treatment (1 or 2 mg/kg) for additional 3 weeks. The effect of CTLA4Ig on TAC-induced DM in vivo and in vitro was evaluated by assessing pancreatic islet function, histopathology, oxidative stress, apoptosis, and macrophage infiltration. Results IPGTT in the CTLA4Ig groups did not differ from the control group. In addition, plasma insulin level, glucose-induced insulin secretion, and islet viability were not different between the CTLA4Ig and control groups. In the conversion study, TAC withdrawal ameliorated pancreatic islet dysfunction compared to the TAC group, and conversion to CTLA4Ig further improved pancreatic islet function compared to the TAC withdrawal group. TAC-induced oxidative stress, apoptotic cell death, and infiltration of macrophages decreased with TAC withdrawal, and CTLA4Ig conversion further reduced those values. In the in vitro study, CTLA4Ig decreased TAC-induced pancreatic islet cell death and ROS production. Conclusions CTLA4Ig was not diabetogenic, and conversion to CTLA4Ig reduced TAC-induced pancreatic islet injury. *Corresponding author: Chul Woo Yang, MD, Department of Internal Medicine, Seoul St. Mary's Hospital, 505 Banpo-Dong, Seocho-Ku, 137-040, Seoul, Republic of Korea. Fax: +82-2-536-0323, Phone: +82-2-2258-6037, E-mail: yangch@catholic.ac.kr Author's contributions: LJ contributed to the experimental surgeries, analyzed the data, and co-drafted the manuscript; JJ and KL performed the experiments and analyzed the data; SWL, EJK, BHC, and HLL retrieved and analyzed the data; SWL and CWY designed the study and co-drafted the manuscript. All authors read and approved the final manuscript. Disclosure: The authors declare no conflicts of interest. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.

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