Early results of a randomized two-by-two factorial phase II trial comparing neoadjuvant chemotherapy with two and four courses of cisplatin/S-1 and docetaxel/cisplatin/S-1 as neoadjuvant chemotherapy for locally advanced gastric cancer.

BACKGROUND: Neoadjuvant chemotherapy (NAC) is a promising method of improving the survival of resectable gastric cancer. Cisplatin/S-1 (CS) and docetaxel/cisplatin/S-1 (DCS) are both effective against metastatic gastric cancer. This report clarified the impact of these regimens on early endpoints, including the pathological responses, chemotherapy-related toxicities, and surgical results. METHODS: Patients with M0 and either T4 or T3 in case of junctional cancer or scirrhous type received two or four courses of cisplatin (60 mg/m2 at day 8)/S-1 (80 mg/m2 for 21 days with 1 week rest) or docetaxel (40 mg/m2 at day 1)/cisplatin (60 mg/m2 at day 1)/S-1 (80 mg/m2 for 14 days with 2 weeks rest) as NAC. Patients then underwent D2 gastrectomy and adjuvant S-1 chemotherapy for 1 year. The primary endpoint was the 3-year overall survival. RESULTS: Between October 2011 and September 2014, 132 patients were assigned to receive CS (n = 66; 33 in 2 courses and 33 in 4 courses) or DCS (n = 66; 33 in 2 courses and 33 in 4 courses). The respective major grade 3 or 4 hematological toxicities (CS/DCS) were leukocytopenia (14.1%/26.2%), neutropenia (29.7%/47.7%), anemia (14.1%/12.3%), and platelet reduction (3.1%/1.5%). The rate of pathological response, defined as a complete response or < 10% residual cancer remaining, was 19.4% in the CS group and 15.4% in the DCS group, and 15.6% in the two-course group and 19.0% in the 4-course group. The R0 resection rate was 72.7% in the CS group and 81.8% in the DCS group and 80.3% in the two-course group and the 74.2% in the four-course group. No treatment-related deaths were observed. CONCLUSIONS: Our results do not support three-drug therapy with a taxane over two-drug therapy, or any further treatment beyond two cycles as an attractive candidate for the test arm of NAC.

Living-Donor Liver Transplantation Using Segment 2 Monosegment Graft: A Single-Center Experience.

BACKGROUND: In small infants, left lateral segment grafts are sometimes too large to overcome the problems of large-for-size grafts in the abdominal compartment. To address this problem, we have developed a safe living donor graftectomy for neonates, a so-called "S2 monosegment graft" to minimize graft thickness. We reviewed our single-center experience to evaluate the feasibility of this technique for reducing graft size. METHODS: Eleven living-donor liver transplants using S2 monosegment grafts were performed between October 2008 and September 2014 at our institution. Medical records of both donors and recipients were reviewed and data collected retrospectively. RESULTS: The mean age of recipients at the time of transplantation was 125.3 days, including 3 neonates. The average S2 monosegment graft weight was 127.4 g, and the graft-to-recipient body weight ratio was successfully reduced to 3.5%. The graft livers were reduced to 4.1 cm in thickness. Two recipients with grafts larger than 5 cm could not undergo primary abdominal closure. Portal vein stenosis and biliary stenosis was observed in 1 recipient, and hepatic artery complications were seen in 2 recipients; the clinical course for all donors were uneventful. Liver regeneration was seen in every patient. The graft and patient 1-year survival rate was 100%. CONCLUSIONS: Living-donor liver transplantation using S2 monosegment grafts offers a safe and useful option for treating smaller infants. Here, we introduce our method of S2 monosegment graft emphasizing the donor harvest and graft thickness.

Clinical characteristics and outcomes of adenovirus infection of the urinary tract after renal transplantation.

BACKGROUND: Urinary tract infection caused by human adenovirus (HAdV) after renal transplantation (RT) results in graft loss because of concomitant nephropathy and acute rejection and may result in death because of systemic dissemination. METHODS: We assessed the time period between RT and disease onset, symptoms, treatment details, disease duration, renal graft function, outcomes, and complications. RESULTS: HAdV infection of the urinary tract occurred in 8 of 170 renal transplant recipients. Symptoms were macrohematuria in all 8 patients, dysuria in 7, and fever in 5. The median period from RT to disease onset was 367 (range, 7-1763) days, and the median disease duration was 15 (range, 8-42) days. The mean serum creatinine (sCr) level prior to onset was 1.35 ± 0.48 mg/dL and the mean maximum sCr level during disease was 2.34 ± 1.95 mg/dL. These values were increased by ≥25% in 5 patients. The mean sCr levels when symptoms resolved was 1.54 ± 0.67 mg/dL, and no significant difference was seen before, during, or after disease onset (P = 0.069). Two patients were diagnosed with HAdV viremia and 1 with acute tubulointerstitial nephritis revealed on biopsy. In addition to a reduction in immunosuppressant dosage, 2 patients received gammaglobulins and 5 received ganciclovir. CONCLUSION: Symptoms of all patients were alleviated, although some patients developed nephritis or viremia. Hence, the possibility of exacerbation should always be considered. Adequate follow-up observation should be conducted, and diligent and aggressive therapeutic intervention is required to prevent the condition from worsening.

Effect of heat stress soon after muscle injury on the expression of MyoD and myogenin during regeneration process.

Heat stress could promote skeletal muscle regeneration. But, in the regeneration process, effects of heat stress on myogenic cells and the regulating factors is unknown. Therefore, Influences of heat stress soon after injury on distribution of the myogenic cells and chronological changes in expression of MyoD and myogenin were examined. The first peak of MyoD expression was temporally correlated with the time when proliferating satellite cells began to appear, and the rapid decline of the MyoD expression from the first peak, with the appearance time of myoblasts, respectively in both the non-Heat and Heat groups. The first peak of myogenin expression was temporally correlated with the time when multinuclear cells began to form in the both groups. Due to the heat stress, proliferation and differentiation of myogenic cells and chronological changes in these factors were accelerated one day earlier than in the non-Heat group. As MyoD and myogenin are regulating factor of proliferation and differentiation, heat stress soon after the muscle injury could accelerate the proliferation and differentiation of myogenic cells and the expression of their regulating factors MyoD and myogenin.

Successful treatment of severe anastomotic stricture of a choledochojejunostomy after living donor liver transplantation with transhepatic cholangioscopy-guided balloon dilatation.

Anastomotic stricture of the choledochojejunostomy is a common complication after living donor liver transplantation. Most anastomotic strictures can be treated by percutaneous transhepatic cholangiodrainage and/or double balloon endoscopy. However, in severe cases and/or in small infants, neither of these is possible. Our new technique, cholangiography accompanied by cholangioscopy, enabled successful guidewire placement and balloon dilatation in cases with severe anastomotic stricture.

Evaluation of viable ß-cell mass is useful for selecting collagenase for human islet isolation: comparison of collagenase NB1 and liberase HI.

The selection of enzyme blend is critical for the success of human islet isolations. Liberase HI collagenase (Roche) was introduced in the 1990s and had been widely used for clinical islet transplantation. More recently, a blend collagenase NB1 has been rendered available. The aim of this study was to evaluate the isolation outcomes and islet quality comparing human islet cells processed using NB1 and Liberase HI. A total of 90 isolations processed using NB1 (n = 40) or Liberase HI (n = 50) was retrospectively analyzed. Islet yield, function in vitro and in vivo, cellular (including ß-cell-specific) viability and content, as well as isolation-related factors were compared. No significant differences in donor-related factors were found between the groups. There were also no significant differences in islet yields (NB1 vs. Liberase: 263,389 ± 21,550 vs. 324,256 ± 27,192 IEQ; p = n.s., respectively). The pancreata processed with NB1 showed a significantly longer digestion time (18.6 ± 0.7 vs. 14.5 ± 0.5 min, p < 0.01), lower ß-cell viability (54.3 ± 3.4% vs. 72.0 ± 2.1%, p < 0.01), ß-cell mass (93,671 ± 11,150 vs. 148,961 ± 12,812 IEQ, p < 0.01), and viable ß-cell mass (47,317 ± 6,486 vs. 106,631 ± 10,228 VßIEQ, p < 0.01) than Liberase HI. In addition, islets obtained with Liberase showed significantly better graft function in in vivo assessment of islet potency. The utilization of collagenase NB1 in human islet isolation was associated with significantly lower ß-cell viability, mass, and islet potency in vivo in our series when compared to Liberase HI, even though there was no significant difference in islet yields between the groups. Evaluation of viable ß-cell mass contained in human islet preparations will be useful for selecting enzyme blends.

PP111. The preceding features before onset of gestational hypertension and preeclampsia in home blood pressure monitoring: The existence of the inflection point and the rapid increased speed of blood pressure.

INTRODUCTION: It has not been clarified whether home blood pressure monitoring (HBPM) during pregnancy is useful to detect high risk pregnant women with later onset of gestational hypertension (GH) and preeclampsia (PE). OBJECTIVES: We thought to determine the preceding features of blood pressure (BP) in HBPM before the onset of GH and PE. We especially focused on the existence of the inflection point, its level, when it occurs, and the increased speed of BP after the inflection point. We compared these features in normal pregnant women (NP), women with GH, and women with PE. METHODS: In this prospective cohort study, 361 singleton pregnant women, among them 100 women recruited due to high risk for GH/PH in the second trimester, participated in a couple of tertiary perinatal centers between 2008 and 2010. HBPM were measured with the validated OMRON HEM-5001(R) automated digital oscillometric sphygmomanometer (OMRON Healthcare Japan). The device was programmed to take three consecutive readings at 15-second interval. HBPM was measured twice a day, at the time of awakening and sleep, through the first to third trimester, and the average systolic blood pressure (SBP) and diastolic blood pressure (DBP) of each gestational week (almost 42 times a week) were calculated. We defined the data of HBPM which started before 28 gestational weeks and continued until 2 weeks before the onset of GH/PE or delivery are eligible. The increased speed of systolic or diastolic BP after the inflection point was defined as ("BP at the onset in GH/PE or at delivery in NP" - "BP at the inflection point") / ("Gestational weeks at the onset in GH/PE or at delivery in NP" - "Gestational weeks at the inflection point"). If there was no inflection point in HBPM, the increased speed of BP was defined as zero. The comparisons were performed using one-way analysis of variance (ANOVA) followed by multiple comparison. Data were shown as mean±SE. RESULTS: A total of 17 (4.7%) women developed PE, and 12 (3.3%) GH.The systolic blood pressure (SBP) levels at the inflection point in NP, GH and PE was 102.4±1.3, 118.7±2.9 and 117.4±2.2mmHg, respectively (Significant pairs: NP < GH, PE); the diastolic blood pressure (DBP) levels at the inflection point was 59.2±1.0, 74.5±2.0 and 73.1±2.0mmHg, respectively (NP < GH, PE). The inflection point in NP, GH and PE occurred at 31.3±0.9, 28.4±1.5 and 22.3±1.4weeks, respectively (PE < GH, NP). The increased speed of SBP in NP, GH and PE was 1.2±0.1, 3.0±0.4 and 4.7±0.7mmHg/wk, respectively (NP < GH, PE); the increased speed of DBP was1.1±0.1, 2.1±0.3 and 2.8±0.4mmHg/wk, respectively (NP < GH, PE). CONCLUSION: In women with later onset of GH/PE, the BP level at the inflection points was higher than in NP. The average inflection point in PE was earlier gestational weeks than in GH and NP. The average increased speed of blood pressure after the inflection point in GH/PE was faster than in NP. The preceding features of BP in HBPM may be clinically useful to detect high risk women with later onset of GH/PE.

Individual differences in prothrombin time-international normalized ratio variation following coadministration of the anticancer agents S-1 and warfarin: 3 case reports.

OBJECTIVE: We report three cases of elevated prothrombin time-international normalized ratios (PT-INR) following the initiation of coadministration of warfarin and S-1, a preparation containing tegafur (FT), gimeracil (CDHP), and oteracil potassium (Oxo). CASE SUMMARIES: The three cases included 2 men and 1 woman aged 79, 71, and 54 y, respectively. PT-INRs were in the range of 2.0 - 3.0 before therapy but were elevated to values in the range of 3.79 - 4.92 within 8 - 17 days after initiating the coadministration of warfarin (1.5 - 3.5 mg/d) and S-1 (80 - 120 mg/d). When the drug interactions in Cases 1 - 3 were evaluated using the Drug Interaction Probability Scale, each of these cases was assessed as "probable". DISCUSSION: The drug interaction between warfarin and S-1 presumably leads to elevated PT-INR because the 5-fluorouracil (5-FU), which is metabolite of FT in S-1, inhibits the metabolic processing of S-warfarin by cytochrome P450 (CYP) 2C9. However, individual differences in the metabolic production of 5-FU from FT because of genetic polymorphisms in CYP2A6 and individual variation in the levels of renal function may lead to complications when 5-FU is coadministered with warfarin as compared to when 5-FU is administered alone. CONCLUSION: It is essential that the dosage level of warfarin is appropriately adjusted by frequent PT-INR measurements when warfarin and S-1 are coadministered.

Learning curve of laparoscopy-assisted gastrectomy using a standardized surgical technique and an established educational system.

BACKGROUND AND AIMS: The learning curve of a trainee for laparoscopy-assisted gastrectomy in a high volume center, in which an educational system and a standardized laparoscopic procedure are already established, remains unclear. MATERIAL AND METHODS: The early surgical outcomes of the patients of two trainees were investigated. Both trainees followed a training program where they performed at least 20 cases being the camera assistant, 20 cases being the first assistant, before performing the surgery as an operator. RESULTS: The average operation time, intraoperative bleeding, the number of retrieved lymph nodes, and morbidity rate were 240.2 min, 45.7 ml, 35.4, and 13.0%, respectively. There was no learning curve effect observed except with the operation time of one trainee. CONCLUSIONS: In a high volume center with an established educational system, trainees could perform laparoscopy-assisted gastrectomy safely, although there might be a -learning curve effect in operation time and the surgeries took longer operation time in trainee's initial cases.

Warfarin and miconazole oral gel interactions: analysis and therapy recommendations based on clinical data and a pharmacokinetic model.

WHAT IS KNOWN AND OBJECTIVE: Miconazole is a strong inhibitor of CYP2C9, one of the main enzymes involved in the metabolism of warfarin. Concurrent use of the two drugs leads to potentially serious adverse effects. Although it is often assumed that use of the oral miconazole gel is acceptable with concomitant warfarin, because of the low bioavailability following buccal administration, drug-drug interactions have been reported following such use. We aimed to investigate case reports of such interactions and develop a pharmacokinetic model to model such interactions. METHODS: The Medline database from 1966 to October 2010 was used for literature search. Case reports of the potentiation of the anticoagulant effects of warfarin, such as the elevation of prothrombin time (INR), by concomitant administration of warfarin and miconazole oral gel were collected. We quantitatively estimated the extent of inhibition of warfarin metabolism by orally administered miconazole gel and compared our findings with case reports. RESULTS AND DISCUSSION: Metabolism of (S)-warfarin is inhibited potently following administration of a standard dose (200-400 mg/day in Japan) of miconazole gel. This may lead to in an increase in the blood concentration of warfarin and lead to serious adverse effects. The literature reports of clinical interactions with concomitant use of those drugs show that other factors may amplify the effects of any increase in blood concentration. WHAT IS NEW AND CONCLUSION: We summarize all reported, clinically significant, cases of drug interaction between miconazole oral gel and warfarin. Pharmacokinetic modelling shows that concomitant administration of warfarin and miconazole oral gel can lead to substantial increase in warfarin concentration. However, our PK/PD model fails to capture the dramatic increases seen in INR values, and hence bleeding complications, reported in the literature. Taken together, the evidence suggests that concomitant use of miconazole gel and warfarin should be avoided. Even over-the-counter products containing miconazole should be used with caution by patients receiving warfarin.

Antiproinflammatory effects of iodixanol (OptiPrep)-based density gradient purification on human islet preparations.

Islet isolation and purification using a continuous density gradient may reduce the volume of tissue necessary for implantation into patients, therefore minimizing the risks associated with intraportal infusion in islet transplantation. On the other hand, the purification procedure might result in a decreased number of islets recovered due to various stresses such as exposure to cytokine/chemokine. While a Ficoll-based density gradient has been widely used in purification for clinical trials, purification with iodixanol (OptiPrep) has been recently reported in islet transplant series with successful clinical outcomes. The aim of the current study was to compare the effects of the purification method using OptiPrep-based and Ficoll-based density gradients. Human islet isolations were performed using a modified automated method. After the digestion phase, pre-purification digests were divided into two groups and purified using a semiautomated cell processor with either a continuous Ficoll- or OptiPrep-based density gradient. The quantity, purity, viability, and cellular composition of islet preparations from each group were assessed. Cytokine/chemokine and tissue factor production from islet preparations after 48-h culture were also measured. Although islet purity, post-purification IEQ, islet recovery rate, FDA/PI, and fractional ß-cell viability were comparable, ß-cell mass after 48-h culture significantly improved in the OptiPrep group when compared to the Ficoll group. The production of cytokine/chemokine including IL-1ß, TNF-α, IFN-γ, IL-6, IL-8, MIP-1ß, MCP-1, and RANTES but not tissue factor from the OptiPrep group was significantly lower during 48-h culture after isolation. Each preparation contained the similar number of ductal cells and macrophages. Endotoxin level in both gradient medium was also comparable. The purification method using OptiPrep gradient media significantly reduced cytokine/chemokine production but not tissue factor from human islet preparations and improved ß-cell survival during pretransplant culture. Our results suggest that the purification method using OptiPrep gradient media may be of assistance in increasing successful islet transplantation.

Toward improving human islet isolation from younger donors: rescue purification is efficient for trapped islets.

Several reports suggest that islets isolated from younger donor pancreata are of better quality for clinical islet transplantation. The relative inefficiency of the continuous gradient purification process (CGP) is one of the major obstacles to the utilization of these younger donor pancreata. This study demonstrates the benefits of utilizing an additional purification step, rescue gradient purification (RGP), to recover trapped islets and examines the possible superiority of these rescued islets. Seventy-three human islet isolations purified by RGP following CGP were divided into two groups based on age, and the isolation results were retrospectively analyzed (group I: age < or = 40, group II: age > 40). The quality of islets from both CGP and RGP were assessed by beta-cell fractional viability (beta FV) and ADP/ATP ratio. Significant increases in the percent islet recovery from RGP and the percent trapped islets in group I compared to group II were observed. Donor age correlated negatively to the percent islets recovered from RGP (R = 0.440) and to the percent of trapped islets (R = 0.511). RGP islets had higher beta FV and better ADP/ATP ratio compared to CGP islets. In conclusion, RGP improved the efficiency in the purification of trapped islets, which often come from younger donor pancreata. The better quality of beta-cells in RGP islets encourages us to perform RGP, considering the higher quality as well as the quantity of remaining islets.

In situ quantitative immunoprofiling of regulatory T cells using laser scanning cytometry.

Laser scanning cytometry (iCys; CompuCyte, Cambridge, Mass) has recently been developed to use fluorescence-based quantitative measurements on tissue sections or other cellular preparations at a single-cell level. The purpose of this study was to develop objective, quantitative immunoprofiling of regulatory T cells (T regs) on formalin-fixed/paraffin-embedded (FFPE) biopsy samples from transplanted allografts using iCys. We sought to evaluate the usefulness of iCys to analyzes the population of CD4 (+) Foxp3 (+) T regs among CD4 (+) T-cell and the entire T-cell (the total of CD4 [+] and CD8 [+] populations in human intestinal allograft biopsy samples. Primary antibodies (Foxp3 and CD4) which had been labeled using Alexa Fluoro 488 (Foxp3 Alexa488) and 647 (CD4 Alexa647) with polymer horseradish peroxidase and catalyzed signal amplification were incubated on 1 section. On the other section, CD8 and CD4 were labeled using Alexa488 and Alexa647 using the same protocol. Data acquisition was performed using iCys. The signal intensities of Alexa488 and Alexa647 were sufficient to analyze by iCys. Distribution of the integrals of Alexa488 and Alexa647 to visualize each cell population enabled calculation of the population of T reg among CD4 (+) T cells, CD4 (+) T cells among total T cells, and T reg among entire T cells. iCys and signal amplified immunofluorescent staining allowed objective quantitative immunoprofiling of in situ T reg populations, with precise quantitative analysis at a single-cell level on FFPE sections. This objective method may be applied on biopsy samples from various transplanted organs.

Purification method using iodixanol (OptiPrep)-based density gradient significantly reduces cytokine chemokine production from human islet preparations, leading to prolonged beta-cell survival during pretransplantation culture.

Purification is one of the most important steps in human islet isolation. Although Ficoll-based density gradients are widely used, OptiPrep-based density gradients are used in few centers. Cytokine/chemokine production from human islet preparations varies widely. Some cytokines/chemokines have been reported to have adverse effects on human islet preparations. Control of cytokine/chemokine production may be a key to improve islet quality and quantity, leading to better transplantation outcomes. The aim of the present study was to investigate the effects on islet preparations of purification methods using various density gradients on viability, cellular composition, and proinflammatory cytokine/chemokine production. After the digestion phase, the extracts were divided into 2 groups for purification using a semiautomated cell processor with Ficoll-based or OptiPrep-based density gradients. Islet preparations cultured for 2 days were assessed regarding islet cell viability (fluorescein diacetate/propidium iodide [FDA/PI]), fractional beta-cell viability by FACS, and beta-cell content using iCys. Cytokine/chemokine production from islet preparations was also measured by Bio-plex. After purification, the purity, islet equivalents (IEQ), and islet recovery rates were comparable between the 2 groups. Although FDA/PI and fractional beta-cell viability showed no significant difference, survival of beta cells during culture was significantly higher in the OptiPrep compared with the Ficoll-based density gradient group. There were significantly lower tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, interferon (IFN)-gamma, IL-6, and MIP-1beta productions from the OptiPrep-based density gradient group. OptiPrep-based density gradients reduced cytokine/chemokine production by islet preparations. In addition, OptiPrep-based density gradient purification significantly reduced the loss of beta-cell mass during pretransplantation culture.

Effect of pituitary adenylate cyclase-activating polypeptide in islet transplantation.

INTRODUCTION: Pituitary adenylate cyclase-activating polypeptide (PACAP) is an islet substance serving as an intra-islet amplifier of glucose-induced insulin secretion similar to exendin-4. It has been reported that systemic administration of PACAP maintained beta-cell mass, delayed the onset of hyperglycemia, and protected beta cells from glucose toxicity. Moreover, PACAP increases glucose-stimulated insulin release in vitro and in vivo. In this study, we investigated the possibility of PACAP use in human islet transplantation. METHODS: Human islets were cultured in the presence or absence of PACAP (10(-12) mol/L) for 48 hours. We assessed beta-cell viability using FACS, cellular composition analysis by iCys/LSC, and glucose-stimulated insulin secretion. In vivo, islets were transplanted beneath the kidney capsule of Streptozotocin-induced diabetic immunodeficient mice. An intravenous glucose tolerance test (IVGTT) was also performed in the presence or absence of PACAP (Peptide International, Louisville, Ky, United States; 1.3 nmol/kg). RESULTS: There were significant improvements in terms of beta-cell viability and cellular composition between islets cultured with or without PACAP, respectively (P < .05). Moreover, glucose-stimulated insulin secretion significantly improved in islets cultured with PACAP compared with controls, respectively (P < .05). Treatment of recipient mice with PACAP resulted in beneficial effects on insulin secretion (PACAP vs control, 13.2 vs 1.9 mU/L), in IVGTT. However, no significant difference was observed in glucose levels between the 2 groups. CONCLUSIONS: Our study indicated that PACAP significantly improved beta-cell viability and survival during culture, and increased insulin secretion in vitro and in vivo. However, blood glucose levels in vivo after an IVGTT did not significantly improve, probably due to increased glucagon secretion from alpha cells. PACAP supplementation to culture medium could be of assistance to improve clinical islet transplantation outcomes.

Factors that affect human islet isolation.

More than 10,000 IEQ/kg recipient weight of islets is often necessary to achieve insulin independence in patients with type 1 diabetes mellitus. Several studies have identified high donor body mass index (BMI) and pancreas size as important factors for the success of human islet isolation. However, the donor shortage underscores the need to improve isolation outcomes from lower BMI pancreas donors and/or small pancreata. The aim of this study was to identify the critical factors that affect isolation outcome. We analyzed the data from 207 isolations performed from 2002 to 2006 with respect to donor characteristics, pancreas condition, and processing variables. More than 3000 IEQ/g pancreas weight was considered to be an acceptable isolation outcome. This goal was obtained from donors with a BMI >30 kg/m2 (P = .002). The pancreatic surface integrity was also a significant factor (P = .02). Moreover, longer digestion times (P = .04) and a greater proportion of trapped islets negatively affected success rates (P = .004). As previously reported, pancreata from high BMI donors were suitable for islet isolation and transplantation, as they yielded higher total islet particle numbers and higher IEQ/g. Although BMI and pancreas size are not controllable due to the organ donor shortage, factors such as pancreatic surface integrity, shorter digestion time, and lower proportions of trapped islets were found to be significant to obtain higher success rates. The development of better protocols and systematic training of processing/procurement teams will be of assistance to increase the number of successful human islet isolations.

Effect of human islet rescue gradient purification on islet yield and fractional Beta cell viability.

It is difficult to consistently obtain sufficient postpurification islet numbers from younger donors because of the higher proportion of trapped islets after pancreas digestion. Continuous gradient purification (CGP), which is currently used in several islet processing centers, sometimes is not efficient in the purification of trapped islets. Rescue gradient purification (RGP) could improve postpurification islet yields, resulting in an increased number of islet cell products that could be transplanted. Sixty-eight human islet isolations, in which CGP was followed by RGP were analyzed. The quality of islets from CGP and RGP was assessed by beta-cell fractional viability (betaFV) and ADP/ATP ratio. Donor age negatively correlated with the proportion of the islets rescued by RGP (R = -0.52; P < .01) and to the percentage of trapped islets (R = -0.46; P < .01). Age-related differences were observed in pancreas weight, digestion time, and islet yields from CGP, respectively. Importantly, islets from RGP had an 11% higher betaFV compared with islets from CGP. ADP/ATP ratio was also lower in RGP islets versus CGP islets. RGP improved the efficiency of islet purification from younger pancreata and did not affect islet cell viability, which was actually higher in RGP fractions, indicating that rescued trapped islets from the pellet and lower purity layers are not damaged by the extra purification step and may actually be more viable. RGP could be used to rescue high-quality islets from less than 30% pure islet fractions, which are often discarded in the clinical setting.