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

Abstract

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 A , 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 A (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.

Differential expression and release of exosomal miRNAs by human islets under inflammatory and hypoxic stress

“…Blood samples were also tested from six patients admitted for TPIAT at Baylor University Medical Center. Islets were isolated from the pancreas (procured after total pancreatectomy) as described previously (see electronic supplementary material [ESM] Method 1) [12]. Islets were cultured in CMRL 1066 medium containing 10% exosomedepleted FBS, 2 mmol/l glutamine, 100 U/ml penicillin and 100 μg/ml streptomycin at 37°C and 5% CO 2 .…”

“…In islet transplantation, islets are subjected to stresses during procurement, isolation and engraftment. Upon transplantation, islets release miRNAs that are detected in the circulation [12,13]. These miRNA species are packed in exosomes that confer resistance to degradation.…”

“…Several miRNAs correlate with islet damage and transplant outcomes. Notably, elevated hsa-miR-375 in the transplant medium and in sera of islet transplant recipients correlates with lower islet yield and poor transplant outcomes, respectively [12][13][14]. Elevated hsa-miR-200c is a predictive biomarker of endocrine outcome 1 year after islet autotransplantation [11].…”

Circulating miRNA or circulating DNA—Potential biomarkers for organ transplant rejection

“…Moreover, in pancreatic islets undergoing autologous transplantation, high‐quality islets are essential for better post‐transplantation endocrine function; however, pressure during the separation affects quality and yield. Saravanan et al analyzed islet‐rich miRNA‐375 and miRNA‐200c released during isolation to assess injury and correlate the data with post‐transplant endocrine function. The results indicate that measuring the absolute amount of miRNA‐375 and miRNA‐200c released during islet isolation is a useful tool to assess islet damage.…”

Redox-Dependent Inflammation in Islet Transplantation Rejection

“…Prior to the late 1990s, islet transplantation into human patients had very little success in maintaining euglycemia and preventing hypoglycemic events, with few patients being insulin-independent beyond 1 week after transplantation ( 9 ). Since the 1980s, digestive enzymes and a mechanical shaking process known as the Ricordi method have been used to isolate islets ( 10 , 11 ). Then, in 2000, a group led by Dr. James Shapiro at the University of Alberta published what would come to be known as the Edmonton protocol ( 12 ).…”