One hundred human pancreatic islet isolations at Baylor Research Institute

Isolation and Purification of Human Pancreatic Islets

Successful islet isolation is the key to islet transplantation in diabetic patients. However, islet isolation is a technically complex and time-consuming manual process. Optimizing the islet isolation process can improve islet yield and quality, reduce operators, and thus reduce costs.The isolation and purification of human islets include pancreas acquisition and preservation, pancreas digestion, islet purification, islet culture, and islet quality identification. Briefly, after the duodenum was removed, the pancreas was trimmed, the main pancreatic duct was intubated at the distal end of the pancreatic head, collagenase was injected into the pancreatic duct, and the perfused pancreatic tissue was cut and then digested in a Ricordi chamber. A digestion temperature of 37 °C was continuously used to assess the number of samples and the integrity of the lysed and released islets. At the end of the digestion process, collect the digested tissue in a 500 mL centrifuge tube prefilled with 25 mL of cold (4 °C) human serum albumin and centrifuge twice at 150 g for 3 min. After mixing with UW solution as islet storage solution, put it on ice (shake occasionally to prevent clumping) after 30 min. Digested pancreatic tissue was centrifuged at 2200 rpm for 5 min in a COBE 2991 cell processor to isolate islets from exocrine tissue using a continuous density gradient. The purified islet fractions were washed twice in HBSS supplemented with 10% human serum albumin and finally collected in CMRL1066 medium supplemented with the corresponding liquid. The purity of purified islets was calculated by DTZ staining, the survival rate of islets was calculated by FDA/PI staining, and islet function was determined by in vitro glucose-stimulated insulin secretion test.

A comparison of the inflammatory response following autologous compared with allogenic islet cell transplantation

Background

The initial response to islet transplantation and the subsequent acute inflammation is responsible for significant attrition of islets following both autologous and allogenic procedures. This multicentre study compares this inflammatory response using cytokine profiles and complement activation.

Methods

Inflammatory cytokine and complement pathway activity were examined in two cohorts of patients undergoing total pancreatectomy followed either by autologous (n=11) or allogenic (n=6) islet transplantation. Two patients who underwent total pancreatectomy alone (n=2) served as controls.

Results

The peak of cytokine production occurred immediately following induction of anaesthesia and during surgery. There was found to be a greater elevation of the following cytokines: TNF-alpha (P<0.01), MCP-1 (P=0.0013), MIP-1α (P=0.001), MIP-1β (P=0.00020), IP-10 (P=0.001), IL-8 (P=0.004), IL-1α (P=0.001), IL-1ra (0.0018), IL-10 (P=0.001), GM-CSF (P=0.001), G-CSF (P=0.0198), and Eotaxin (P=0.01) in the allogenic group compared to autografts and controls. Complement activation and consumption was observed in all three pathways, and there were no significant differences in between the groups although following allogenic transplantation ∆IL-10 and ∆VEGF levels were significantly elevated those patients who became insulin-independent compared with those who were insulin-dependent.

Conclusions

The cytokine profiles following islet transplantation suggests a significantly greater acute inflammatory response following allogenic islet transplantation compared with auto-transplantation although a significant, non-specific inflammatory response occurs following both forms of islet transplantation.

Pilot study: deficiency of mannose-binding lectin-dependent lectin pathway, a novel modulator in outcome from pancreatic islet auto-transplantation

Background

Numerous factors influence pancreatic islet survival following auto-transplantation. Of these, the host immune response in the early peri-operative period is one of the most important. In this study we investigated the role of the mannose-binding lectin (MBL)-dependent pathway in a group of total pancreatectomy (TP) islet auto-transplantation (TPIAT) patients and classified them as competent or deficient in MBL activity. Complement pathway activities, MBL protein and inflammatory cytokine concentrations were evaluated from eleven pancreatic islet auto-transplant patients from two institutions.

Methods

Eleven patients from two institutions were prospectively recruited. Serum was screened at different time points for 29 different cytokines and compared according to their MBL deficient or competent status. Twelve patients from previous TPIAT patients also underwent screening of MBL pathway activity.

Results

A total nine of twenty three patients (39%) were MBL pathway deficient. MCP-1, IL-7 and IL-1a concentrations were significantly lower in the MBL deficient cohort compared to the normal MBL group (P=0.0237, 0.0001 and 0.0051 respectively). IL-6 and IL-8 concentrations were significantly raised in the normal MBL group. MBL functional activity was lower in insulin-independent group compared to the insulin-dependent group.

Conclusions

Complement activation is an important, possibly damaging response during intra-portal islet infusion. MBL pathway deficiency appears common in this population and the cytokine response was attenuated in MBL pathway deficient patients. Therapeutic MBL pathway blockade during and following islet auto-transplantation (IAT) may improve islet survival and function and thereby clinical outcome.

Operative management of chronic pancreatitis: A review

BACKGROUND

Pain secondary to chronic pancreatitis is a difficult clinical problem to manage. Many patients are treated medically or undergo endoscopic therapy and surgical intervention is often reserved for those who have failed to gain adequate pain relief from a more conservative approach.

RESULTS

There have been a number of advances in the operative management of chronic pancreatitis over the last few decades and current therapies include drainage procedures (pancreaticojejunostomy, etc.), resection (pancreticoduodenectomy, etc.) and combined drainage/resection procedures (Frey procedure, etc.). Additionally, many centers currently perform total pancreatectomy with islet autotransplantation, in addition to minimally invasive options that are intended to tailor therapy to individual patients.

DISCUSSION

Operative management of chronic pancreatitis often improves quality of life, and is associated with low rates of morbidity and mortality. The decision as to which procedure is optimal for each patient should be based on a combination of pathologic changes, prior interventions, and individual surgeon and center experience.

Pancreatic ductal perfusion at organ procurement enhances islet yield in human islet isolation

OBJECTIVE

Pancreas preservation is a major factor influencing the results of islet cell transplantation. This study evaluated the effects of 2 different solutions for pancreatic ductal perfusion (PDP) at organ procurement.

METHODS

Eighteen human pancreases were assigned to 3 groups: non-PDP (control), PDP with ET-Kyoto solution, and PDP with cold storage/purification stock solution. Pancreatic islets were isolated according to the modified Ricordi method.

RESULTS

No significant differences in donor characteristics, including cold ischemia time, were observed between the 3 groups. All islet isolations in the PDP groups had more than 400,000 islet equivalence in total islet yield after purification, a significant increase when compared with the control (P = 0.04 and P < 0.01). The islet quality assessments, including an in vivo diabetic nude mice assay and the response of high-mobility group box protein 1 to cytokine stimulation, also showed no significant differences. The proportion of terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells showing apoptosis in islets in the PDP groups was significantly lower than in the control group (P < 0.05).

CONCLUSIONS

Both ET-Kyoto solution and cold storage/purification stock solution are suitable for PDP and consistently resulted in isolation success. Further studies with a larger number of pancreas donors should be done to compare the effects of the PDP solutions.

Advances in transplantation 1940-2014

The history of medicine is that what was inconceivable yesterday and barely achievable today often becomes routine tomorrow. Liver transplantation began with almost no resources at the same time as the tentative first steps were taken to land a man on the moon. Because human lives would be at stake, both objectives had a sacramental element from the outset: a solemnly binding commitment to perfection. The gift of an organ is really a gift of life, and something as valuable as a life-saving organ is more important to a suffering patient than wealth or power. The concept of a team approach to the care of the transplant patient is an important factor in the development of a successful program. This has resulted in recipient survival rates reaching 90% at one year.

SUITO index for evaluation of clinical islet transplantation

The major endpoints for clinical islet transplantation for type 1 diabetes are insulin independence and reduction of hypoglycemic episodes. Both endpoints are influenced by patients' and physicians' preferences regarding the use of exogenous insulin. Therefore, development of an objective endpoint for assessing clinical islet transplantation is desirable. HOMA-beta score is useful in assessing functional β-cell mass. However, this score uses blood insulin levels that are influenced by exogenous insulin injection and therefore is not suitable for patients who receive exogenous insulin. For assessing functional β-cell mass for type 1 diabetic patients after islet transplantation, we created the Secretory Unit of Islet Transplant Objects (SUITO) index using fasting C-peptide and fasting glucose. The formula of the SUITO index is fasting C-peptide (ng/ml)/[fasting blood glucose − 63 (mg/dl)] × 1500. We demonstrated that, within 1 month of islet transplantation, an average SUITO index of >26 was an excellent predictor of achieving insulin independence. In addition, daily SUITO index scores correlated with a reduction of insulin dose and adversely correlated with blood glucose levels during an intravenous glucose tolerance test. Other important endpoints, reduction of hypoglycemic episodes and quality of life, also correlated with the SUITO index. Thus, the SUITO index is excellent for assessing important endpoints (insulin independence, reduction of hypoglycemia, improved quality of life) after allogeneic islet transplantation.

Withaferin A inhibits pro-inflammatory cytokine-induced damage to islets in culture and following transplantation

AIMS/HYPOTHESIS

Beta cell death triggered by pro-inflammatory cytokines plays a central role in the pathogenesis of type 1 diabetes and loss of transplanted islets. The nuclear factor κB (NF-κB) signalling pathway is a key regulator of beta cell stress response, survival and apoptosis. Withaferin A (WA), a steroidal lactone derived from Withania somnifera, has been demonstrated to be a potent, safe, anti-inflammatory molecule that can inhibit NF-κB signalling. Therefore, we evaluated the ability of WA to protect mouse and human islets from the damaging effects of pro-inflammatory cytokines in vitro and following intraportal transplantation.

METHODS

Mouse and human islets were treated with a cytokine cocktail, and NF-κB activation was measured by immunoblots, p65 nuclear translocation and chromatin immunoprecipitation of p65-bound DNA. Intraportal transplantation of a marginal mass of syngeneic mouse islets was performed to evaluate the in vivo protective effect of WA.

RESULTS

Treatment with WA substantially improved islet engraftment of syngeneic islets (83% for infusion with 200 islets + WA; 0% for 200 islets + vehicle) in a mouse model of diabetes, compared with marginal graft controls with superior islet function in WA-treated mice confirmed by glucose tolerance test. Treatment of human and mouse islets with WA prevented cytokine-induced cell death, inhibited inflammatory cytokine secretion and protected islet potency.

CONCLUSIONS

WA was shown to be a strong inhibitor of the inflammatory response in islets, protecting against cytokine-induced cell damage while improving survival of transplanted islets. These results suggest that WA could be incorporated as an adjunctive treatment to improve islet transplant outcome.

Ductal injection does not increase the islet yield or function after cold storage in a vascular perfusion model

Several studies have reported that pancreatic ductal preservation greatly improved the islet yield and function after cold storage. However, these studies were devoid of appropriate controls, such as vascular perfusion, which is routinely performed to preserve organs in the clinical setting. In this study, we created a vascular perfusion model using inbred rats, and investigated the effect of ductal injection on the islet yield and function after cold storage. Rat pancreases after 10 h cold ischemia were classified as follows: without ductal/vascular perfusion; with ductal injection; with vascular perfusion; and with ductal/vascular perfusion. The islet yield, function, viability, release of inflammatory mediators, and pathological changes in the exocrine tissues were assessed in the Hanks' Balanced Salt Solution (HBSS) model. The islet yield was also assesed by introducing University of Wisconsin Solution (UWS) and Histidine-Tryptophan-Ketoglutarate solution (HTK), which are the standard clinical preservation solutions. In the HBSS model, ductal injection and vascular perfusion significantly improved the islet yield compared with the control group. However, ductal injection showed no additional effects on the islet yield, function, viability and suppressing the release of inflammatory mediators when vascular perfusion was performed. Although ductal injection significantly decreased the apoptosis of exocrine cells, no beneficial effect on vacuolation was observed. In contrast, vascular perfusion significantly suppressed vacuolation in the exocrine tissues. Likewise, in the UWS and HTK model, ductal injection and vascular perfusion improved the islet yield compared with the control group. Nevertheless, the combination group showed no additional effects. These data suggest that ductal injection has no additional effect on islet yield and function after cold storage in a vascular perfusion model. We propose that ductal injection can be an effective and simple alternative for vascular perfusion prior to pancreas harvest, but is not necessary in most cases, since vascular perfusion is routinely performed.

Impact of tissue volume and purification on clinical autologous islet transplantation for the treatment of chronic pancreatitis

Autologous islet transplantation after total pancreatectomy is an excellent treatment for painful chronic pancreatitis. Traditionally, islets have been isolated without purification; however, purification is applied when the tissue volume is large. Nevertheless, the impact of tissue volume and islet purification on clinical outcomes of autologous islet transplantation has not been well examined. We analyzed 27 cases of autologous islet transplantation performed from October 2006 to January 2011. After examining the relationship between tissue volume and portal pressure at various time points, we compared islet characteristics and clinical outcomes between cases with complications (complication group) and without (noncomplication group), as well as cases with purification (purification group) and without (nonpurification group). Tissue volume significantly correlated with maximum (R = 0.61), final (R = 0.53), and delta (i.e., difference between base and maximum; R = 0.71) portal pressure. The complication group had a significantly higher body mass index, tissue volume, islet yield, and portal pressure (maximum, final, delta), suggesting that complications were associated with high tissue volume and high portal pressure. Only one of four patients (25%) in the complication group became insulin free, whereas 11 of 23 patients (49%) in the noncomplication group became insulin free with smaller islet yields. The purification group had a higher islet yield and insulin independence rate but had similar final tissue volume, portal pressure, and complication rates compared with the nonpurification group. In conclusion, high tissue volume was associated with high portal pressure and complications in autologous islet transplantation. Islet purification effectively reduced tissue volume and had no negative impact on islet characteristics. Therefore, islet purification can reduce the risk of complications and may improve clinical outcome for autologous islet transplantation when tissue volume is large.

Islet transplantation: factors in short-term islet survival

Islet transplantation has the potential to cure type 1 diabetes. In recent years, the proportion of patients achieving initial insulin independence has improved, but longer term outcomes remain poor compared to those for whole pancreas transplants. This review article will discuss factors affecting islet yield and viability leading up to transplantation and in the immediate post-transplant period.

Clinical allogeneic and autologous islet cell transplantation: update

Islet cell transplantation is categorized as a β-cell replacement therapy for diabetic patients who lack the ability to secrete insulin. Allogeneic islet cell transplantation is for the treatment of type 1 diabetes, and autologous islet cell transplantation is for the prevention of surgical diabetes after a total pancreatectomy. The issues of allogeneic islet cell transplantation include poor efficacy of islet isolation, the need for multiple donor pancreata, difficulty maintaining insulin independence and undesirable side effects of immunosuppressive drugs. Those issues have been solved step by step and allogeneic islet cell transplantation is almost ready to be the standard therapy. The donor shortage will be the next issue and marginal and/or living donor islet cell transplantation might alleviate the issue. Xeno-islet cell transplantation, β-cell regeneration from human stem cells and gene induction of the naïve pancreas represent the next generation of β-cell replacement therapy. Autologous islet cell transplantation after total pancreatectomy for the treatment of chronic pancreatitis with severe abdominal pain is the standard therapy, even though only limited centers are able to perform this treatment. Remote center autologous islet cell transplantation is an attractive option for hospitals performing total pancreatectomies without the proper islet isolation facilities.