Katie Kinzer

Long-Term Metabolic and Immunological Follow-Up of Nonimmunosuppressed Patients With Type 1 Diabetes Treated With Microencapsulated Islet Allografts Four cases

OBJECTIVE To assess long-term metabolic and immunological follow-up of microencapsulated human islet allografts in nonimmunosuppressed patients with type 1 diabetes (T1DM). RESEARCH DESIGN AND METHODS Four nonimmunosuppressed patients, with long-standing T1DM, received intraperitoneal transplant (TX) of microencapsulated human islets. Anti-major histocompatibility complex (MHC) class I–II, GAD65, and islet cell antibodies were measured before and long term after TX. RESULTS All patients turned positive for serum C-peptide response, both in basal and after stimulation, throughout 3 years of posttransplant follow-up. Daily mean blood glucose, as well as HbA1c levels, significantly improved after TX, with daily exogenous insulin consumption declining in all cases and being discontinued, just transiently, only in patient 4. Anti-MHC class I–II and GAD65 antibodies all tested negative at 3 years after TX. CONCLUSIONS The grafts did not elicit any immune response, even in the cases where more than one preparation was transplanted, as a unique finding, compatible with encapsulation-driven “bioinvisibility” of the grafted islets. This result had never been achieved with the recipient’s general immunosuppression.

Robotic transabdominal kidney transplantation in a morbidly obese patient.

Kidney transplantation in morbidly obese patients can be technically demanding. Furthermore, morbidly obese patients experience a high rate of wound infections and related complications, which mostly result from the longer length and extent of the incision. These complications can be avoided through minimally invasive surgery; however, conventional laparoscopic instruments are unsuitable for the safe performance of a kidney transplant in morbidly obese patients. Herein, we report the first minimally invasive, total robotic kidney transplant in a morbidly obese patient. A left, deceased donor kidney was transplanted into a 29‐year‐old woman with a body mass index (BMI) of 41 kg/m2 who had been on hemodialysis for 5 years. The operation was performed intraabdominally using the DaVinci Robotic Surgical System with 4 trocars and a 7 cm midline incision. The operative time was 223 min, and the blood loss was less than 50 cc. The kidney had immediate graft function. No perioperative complications were observed, and the patient was discharged on postoperative day 5 with normal kidney function. Minimally invasive access and robotic technology facilitated the safe performance of a successful kidney transplant in a morbidly obese patient.

Survival of human islets in microbeads containing high guluronic acid alginate crosslinked with Ca2+ and Ba2+

Qi M, Mørch Y, Lacík I, Formo K, Marchese E, Wang Y, Danielson KK, Kinzer K, Wang S, Barbaro B, Kolláriková G, Chorvát D Jr, Hunkeler D, Skjåk‐Bræk G, Oberholzer J, Strand BL. Survival of human islets in microbeads containing high guluronic acid alginate crosslinked with Ca2+ and Ba2+. Xenotransplantation 2012; 19: 355–364.

Reduction in Carotid Intima-Media Thickness After Pancreatic Islet Transplantation in Patients With Type 1 Diabetes

OBJECTIVE Determine the impact of islet transplantation on carotid intima-media thickness (CIMT), a marker for atherosclerosis, in type 1 diabetes without kidney disease. RESEARCH DESIGN AND METHODS Consecutive case series of 15 adults (mean age [SD], 49 years [10 years]; 87% female) with type 1 diabetes for ≥5 years (mean duration [SD], 30 years [12 years]; mean HbA1c [SD], 7.2% [0.9%]), without kidney disease, presenting with severe hypoglycemic unawareness to undergo allogeneic pancreatic islet transplant(s) (one to three each) in a phase 1/2 and 3 clinical trial. Current follow-up ranges from 1 to 5 years (2005–2011). CIMT of the common and internal carotid arteries was measured before and every 12–16 months after the first transplant (two to six CIMTs each) by one ultrasonographer and one blinded reader. CIMT was analyzed as change from baseline to 12- and 50-month follow-up; a combined CIMT score was calculated as the sum of the standardized IMT scores (SD units [SDs]) of both arteries. RESULTS All patients achieved insulin independence after one to three transplants. CIMT decreased at 12 months (n = 15) for the common carotid (−0.058 mm; P = 0.006) and combined score (−1.28 SDs; P = 0.004). In those with 50-month follow-up (n = 7), the decrease in the combined score continued from 12 (−1.59 SDs; P = 0.04) to 50 months (−0.77 SDs; P = 0.04). During follow-up, the decreasing slope of change in CIMT was associated with decreasing slopes of change in HbA1c, lipoproteins, and cardiovascular/inflammatory markers. CONCLUSIONS Islet transplantation may ameliorate diabetes-related atherosclerosis through improved glycemic control consequent to restoring endogenous insulin secretion, and optimal lipid management posttransplant also contributes.

A Recommended Laparoscopic Procedure for Implantation of Microcapsules in the Peritoneal Cavity of Non-human Primates

BACKGROUND The anatomical spatial distribution of microencapsulated islets transplanted into the peritoneal cavity of large animals remains a relatively unexplored area of study. In this study, we developed a new implantation approach using laparoscopy in order to avoid microcapsule amalgamation. This approach constitutes a clinically relevant method, which can be used to evaluate the distribution and in vivo biocompatibility of various types of transplanted microcapsules in the future. MATERIALS AND METHODS Two healthy baboons were implanted intraperitoneally with microencapsulated islets through mini-laparotomy and observed at 76 d after implantation. Nine baboons underwent laparoscopic implantation of approximately 80,000 empty microcapsules. Microcapsule distribution was observed by laparoscopic camera during and after implantation at 1, 2, and 4 wk. At each time point, microcapsules were retrieved and evaluated with brightfield microscopy and histologic analysis. RESULTS Mini-laparotomic implantation resulted in microcapusle aggregation in both baboons. In contrast, laparoscopic implantation resulted in even distribution of microcapsules throughout the peritoneum without sedimentation to the Douglas space in all animals. In eight out of nine animals, retrieved microcapsules were evenly distributed in the peritoneal cavity and presented with no pericapsular overgrowth and easily washed out during laparoscopic procedure. The one exception was attributed to microcapsule contamination with blood from the abdominal wall following trocar insertion. CONCLUSIONS Laparoscopic implantation of microcapsules in non-human primates can be successfully performed and prevents microcapsule aggregation. Given the current widespread clinical application of laparoscopy, we propose that this presented laparoscopy technique could be applied in future clinical trials of microencapsulated islet transplantation.

Dual microfluidic perifusion networks for concurrent islet perifusion and optical imaging

This study explores a new class of duplex microfluidic device which utilizes a dual perifusion network to simultaneously perform live-cell optical imaging of physiological activities and study insulin release kinetics on two islet populations. This device also incorporates on-chip staggered herringbone mixers (SHMs) to increase mixing efficiency and facilitate the generation of user-defined chemical gradients. Mouse islets are used to simultaneously measure dynamic insulin release, changes in mitochondrial potentials, and calcium influx in response to insulin secretagogues (glucose and tolbutamide), and show a high signal-to-noise ratio and spatiotemporal resolution of all measured parameters for both perifusion chambers. This system has many potential applications for studying β-cell physiology and pathophysiology, as well as for therapeutic drug screening. This dual perifusion device is not limited to islet studies and could easily be applied to other tissues and cells without major modifications.

Application of microfluidic technology to pancreatic islet research: first decade of endeavor

β-cells respond to blood glucose by secreting insulin to maintain glucose homeostasis. Perifusion enables manipulation of biological and chemical cues in elucidating the mechanisms of β-cell physiology. Recently, microfluidic devices made of polydimethylsiloxane and Borofloat glass have been developed as miniaturized perifusion setups and demonstrated distinct advantages over conventional techniques in resolving rapid secretory and metabolic waveforms intrinsic to β-cells. In order to enhance sensing and monitoring capabilities, these devices have been integrated with analytical tools to increase assay throughput. The spatio-temporal resolutions of these analyses have been improved through enhanced flow control, valves and compartmentalization. For the first time, this review provides an overview of current devices used in islet studies and analyzes their strengths and experimental suitability. To realize the potential of microfluidic islet applications, it is essential to bridge the gap in design and application between engineers and biologists through the creation of standardized bioassays and user-friendly interfaces.

Histidine-tryptophan-ketoglutarate and university of wisconsin solution demonstrate equal effectiveness in the preservation of human pancreata intended for islet isolation: A large-scale, single-center experience

We previously reported a small-scale study on the efficacy of histidine-tryptophan-ketoglutarate (HTK) solution versus University of Wisconsin (UW) solution on pancreas preservation for islet isolation. In this large-scale, retrospective analysis (n = 252), we extend our initial description of the impact of HTK on islet isolation outcomes and include pancreatic digestion efficacy, purification outcomes, and islet size distribution. Multivariable linear regression analysis, adjusted for donor age, sex, BMI, cold ischemia time, and enzyme, demonstrated similar results for the HTK group (n = 95) and the UW group (n = 157), including postpurification islet yields (HTK: 289,702 IEQ vs. UW: 283,036 IEQ; p = 0.76), percentage of digested pancreatic tissue (HTK: 66.9% vs. UW: 64.1%; p = 0.18), and islet loss from postdigestion to postpurification (HTK: 24,972 IEQ vs. UW: 39,551 IEQ; p = 0.38). Changes in islet size between the postdigestion and postpurification stages were comparable within each islet size category for HTK and UW (p = 0.14–0.99). Tissue volume distribution across purification fractions and islet purity in the top fractions were similar between the groups; however, the HTK group had significantly higher islet purity in the middle fractions (p = 0.003–0.008). Islet viability and stimulation indices were also similar between the HTK and the UW groups. In addition, we analyzed a small sample of patients transplanted either with HTK (n = 7) or UW (n = 8) preserved islets and found no significant differences in posttransplant HbA1c, β-score, and frequency of insulin independence. This study demonstrates that HTK and UW solutions offer comparable pancreas preservation for islet transplantation. More in vivo islet outcome data are needed for a complete analysis of the effects of HTK on islet transplantation.

Robot-assisted pancreatoduodenectomy with preservation of the vascular supply for autologous islet cell isolation and transplantation: a case report

IntroductionFor patients with chronic pancreatitis presenting with medically intractable abdominal pain, surgical intervention may be the only treatment option. However, extensive pancreatic resections are typically performed open and are associated with a substantial amount of postoperative pain, wound complications and long recovery time. Minimally invasive surgery offers an avenue to improve results; however, current limitations of laparoscopic surgery render its application in the setting of chronic pancreatitis technically demanding. Additionally, pancreatic resections are associated with a high incidence of diabetes. Transplantation of islets isolated from the resected pancreas portion offers a way to prevent post-surgical diabetes; however, preservation of the vascular supply during pancreatic resection, which determines islet cell viability, is technically difficult using current laparoscopic approaches. With recent advances in the surgical field, robotic surgery now provides a means to overcome these obstacles to achieve the end goals of pain relief and preserved endocrine function. We present the first report of a novel, minimally invasive robotic approach for resection of the pancreatic head that preserves vascular supply and enables the isolation of a high yield of viable islets for transplantation.Case presentationA 35-year old Caucasian woman presented with intractable chronic abdominal pain secondary to chronic pancreatitis, with a stricture of her main pancreatic duct at the level of the ampulla of Vater and distal dilatation. She was offered a robotic-assisted pylorus-preserving pancreatoduodenectomy and subsequent islet transplantation, to both provide pain relief and preserve insulin-secretory reserves.ConclusionWe present a novel, minimally invasive robotic approach for resection of the pancreatic head with complete preservation of the vascular supply, minimal warm ischemia time (less than three minutes) and excellent islet recovery (134,727 islet equivalent). Our patient is currently pain-free with normal glycemic control. Robot-assisted pylorus-preserving pancreatoduodenectomy and autologous islet transplantation can be safely performed and has the potential to minimize operative traumas as well as to partially preserve endocrine function. Results from this case report suggest that this dual procedure should be considered as a treatment option for patients with chronic pancreatitis at earlier stages of the disease, before irreversible islet loss occurs.

Highly purified versus filtered crude collagenase: comparable human islet isolation outcomes.

This study was designed to retrospectively compare the impact of crude Sigma V collagenase (Sigma V, n = 52) with high-purified Serva NB1 collagenase (Serva NB1, n = 42) on human islet isolation outcomes. A three-step filtration was applied to the crude Sigma V to remove endotoxin contamination and impurities; in addition, this process was used as a lot prescreening tool. Isolation outcomes were determined by digestion efficacy, islet yields, purity, viability, glucose-stimulated insulin release, and endotoxin content. The digestion efficacy between Sigma V and Serva NB1 was statistically significant (Sigma V: 64.71% vs. Serva NB1: 69.71%, p = 0.0014). However, the islet yields were similar (Sigma V: 23422.58 vs. Serva NB1: 271097 IEq, p = 0.23) between groups. There was no significant purity difference observed in fractions with purities greater than 75%. Viability (Sigma V: 93.3% vs. Serva NB1: 94.8%, p = 0.061) and stimulation indexes (Sigma V: 3.41 vs. Serva NB1: 2.74, p = 0.187) were also similar between the two groups. The impact of cold ischemia and age on the isolation outcome in the Sigma V group was comparable to the Serva NB1 group. The endotoxin content of the final products in the filtered Sigma V group was significantly less than that in the high-purified Serva NB1 group (0.022 vs. 0.052 EU/ml, p = 0.003). Additionally, in the Sigma V group there was minimal lot to lot variation and no significant loss of enzymatic activity after filtration. These findings indicate that the use of Sigma V or other crude enzyme blends for research pancreata is warranted to reduce isolation costs and increase the amount of islets available for critical islet research. These findings also validate the need for a systematic enzyme analysis to resolve these inconsistencies in overall enzyme quality once and for all.