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1.
Transplantation ; 103(2): 344-352, 2019 02.
Article in English | MEDLINE | ID: mdl-30557272

ABSTRACT

BACKGROUND: For islet transplantation, pancreas preservation in University of Wisconsin (UW) solution is associated with disadvantages, such as collagenase inhibition, resulting in poor islet yield and islets with poor viability. In this study, we evaluated a novel preservation solution, the extracellular-type c-Jun N-terminal kinase (JNK) inhibitor-containing (EJ) solution. METHODS: The EJ solution has high sodium-low potassium composition with low viscosity compared to UW solution. Moreover, EJ solution contains a recently developed JNK inhibitor from our laboratory. RESULTS: We first compared the performance of EJ solution with that of UW solution. Islet yield before and after purification was significantly higher in the EJ group than in the UW group. Second, we compared the performance of EJ solution with that of EJ solution without the JNK inhibitor (EJ-J solution). After pancreas preservation in EJ solution, JNK activity was maintained at a relatively low level during islet isolation. Islet yield before and after purification was significantly higher in the EJ group than in the EJ-J group. After islet transplantation into streptozotocin-induced diabetic mice, blood glucose levels reached the normoglycemic range in 61.5% and 7.7% of diabetic mice in the EJ and EJ-J groups, respectively. Moreover, EJ solution exhibited reduced inhibition of collagenase digestion compared with UW solution. CONCLUSIONS: Advantages of EJ solution over UW solution were inhibition of JNK activity and reduced collagenase inhibition. EJ solution may therefore be more suitable for islet isolation than UW solution.


Subject(s)
Islets of Langerhans/cytology , JNK Mitogen-Activated Protein Kinases/antagonists & inhibitors , Organ Preservation Solutions/pharmacology , Protein Kinase Inhibitors/pharmacology , Adenosine/pharmacology , Allopurinol/pharmacology , Animals , Blood Glucose/analysis , Cell Separation , Female , Glutathione/pharmacology , Insulin/pharmacology , Islets of Langerhans Transplantation , Mice , Raffinose/pharmacology , Swine
2.
Sci Rep ; 8(1): 11082, 2018 07 23.
Article in English | MEDLINE | ID: mdl-30038242

ABSTRACT

We previously reported that treatment with a JNK inhibitory peptide (11R-JNKI) prevents islet apoptosis and enhances the islet function in vivo. In the present study, we explored more efficient JNK inhibitors. The inhibition of the JNK activity by five types of deletion peptides in 11R-JNKI was investigated. One of the peptides, 8R-sJNKI(-9), significantly prevented JNK activation. At a concentration of 1 µM, 8R-sJNKI(-9) inhibited JNK activity similarly to 10 µM 11R-JNKI and the inhibition of the JNK activity by 10 µM 8R-sJNKI(-9) was significantly greater than that by 10 µM 11R-JNK. To evaluate the effects of 8R-sJNKI(-9), porcine islets were cultured with 1 µM of 8R-sJNKI(-9) or 8R-mutant sJNKI(-9) (8R-mJNKI(-9)). After 1 day of culture, the numbers of islets in the 8R-sJNKI(-9)-treated group was significantly higher than that in the 8R-mJNKI(-9)-treated group. After islet transplantation, the blood glucose levels reached the normoglycemic range in 58.3% of streptozotocin-induced diabetic mice in the 8R-sJNKI(-9) group and 0% of the mice in the 8R-mJNKI(-9)-treated group. These data suggest that 8R-sJNKI(-9) inhibits islet apoptosis and improves islet function.


Subject(s)
Apoptosis/drug effects , Islets of Langerhans Transplantation , JNK Mitogen-Activated Protein Kinases/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Adenosine Triphosphate/metabolism , Amino Acid Sequence , Animals , Diabetes Mellitus, Experimental/pathology , Diabetes Mellitus, Experimental/therapy , Insulin-Secreting Cells/drug effects , Insulin-Secreting Cells/metabolism , JNK Mitogen-Activated Protein Kinases/metabolism , Mice , Protein Kinase Inhibitors/chemistry , Swine , Treatment Outcome
4.
Cell Med ; 10: 2155179017733090, 2018.
Article in English | MEDLINE | ID: mdl-32634178

ABSTRACT

Islet purification is one of the most important steps of islet isolation for pancreatic islet transplantation. We previously reported that a purification method using large plastic bottles effectively achieved a high yield of islets from porcine pancreas. In this study, we evaluated the methods for making a continuous density gradient and loading tissue. One method involved loading digested tissue on top of a continuous density gradient (top loading). The other method involved mixing digested tissue with low-density solution and then making a continuous gradient (mixed loading). There were no significant differences between the 2 purification methods in terms of the islet yield, rate of viability or purity, score, or in the stimulation index after purification. Furthermore, there were no marked differences in the attainability or suitability of posttransplantation normoglycemia. Our study shows the equivalency of these 2 methods of islet purification.

5.
Cell Med ; 10: 2155179018775071, 2018.
Article in English | MEDLINE | ID: mdl-32634189

ABSTRACT

Purification of pancreatic islets is an important step in islet isolation for islet transplantation. In this study, to investigate how a solution composed mainly of Na-lactobionate and histidine (HL) influences the purification of islets, iodixanol was added to a purified solution for porcine islet isolation. A solution (IU) made by adding iodixanol to University of Wisconsin solution and a solution (IHL) made by adding iodixanol to HL solution were used to evaluate the islet isolation performance. We noted no significant differences between the two purification methods with regard to the islet yield, survival rate or purity, score, or stimulation index. These results show that IHL solution is as useful as IU solution for islet purification.

6.
Cell Med ; 10: 2155179018781343, 2018.
Article in English | MEDLINE | ID: mdl-32634190

ABSTRACT

The purification step is one of the most important and difficult procedures in islet isolation for pancreatic islet transplantation. We previously reported that a purification method using large plastic bottles effectively achieved a high yield of islets from the porcine pancreas. In this study, we evaluated the impact of the timing of tissue loading on porcine islet purification using large plastic bottles. One method involved loading digested tissue after creating a continuous density gradient (tissue after gradient [TAG]). The other method involved loading digested tissue before creating a continuous density gradient (tissue before gradient [TBG]). There were no significant differences between TAG and TBG in terms of the islet yield, rates of viability and purity, score, and in the stimulation index after purification. Furthermore, there were no marked differences in the attainability or suitability of post-transplantation normoglycemia. Our study shows the equivalency of these two methods of islet purification.

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