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Publications (117)
Introduction
When GFR is measured (mGFR) using iohexol plasma clearance, results are reported both as a “non-indexed” (mL/min) and “body-surface area (BSA) indexed” to 1.73 m ² . When these two values differ, there is no consensus as to which is preferable to use to determine suitability for living kidney donation (LKD). We sought to compare the di...
Background and Aims: High-throughput in vitro pharmacological toxicity testing is essential for drug discovery. Precision-cut liver slices (PCLS) provide a robust system for screening that is more representative of the complex 3D structure of the whole liver than isolated hepatocytes. However, PCLS are not available as off-the-shelf products, signi...
Organ banking by vitrification could revolutionize transplant medicine. However, vitrification and rewarming have never been demonstrated at the human organ scale. Using modeling and experimentation, we tested the ability to vitrify and rewarm 0.5–3 L volumes of three common cryoprotective agent (CPA) solutions: M22, VS55, and 40% EG+0.6M Sucrose....
Objective
To investigate the long-term outcomes of patients with combined primary sclerosing cholangitis/inflammatory bowel disease (PSC-IBD) undergoing both liver transplantation (LT) and total abdominal colectomy (TAC).
Summary Background Data
The fraction of patients with PSC-IBD that require both LT and TAC is small, thereby limiting significa...
Background
Chronic immunosuppression following pancreas transplantation carries significant risk, including posttransplant lymphoproliferative disease (PTLD). We sought to define the incidence, risk factors, and long‐term outcomes of PTLD following pancreas transplantation at a single center.
Methods
All adult pancreas transplants between February...
Objective
To describe the evolution of pancreas transplantation, including improved outcomes and factors associated with improved outcomes over the past five decades.
Background
The world’s first successful pancreas transplant was performed in December 1966 at the University of Minnesota. As new modalities for diabetes treatment mature, we must ca...
There is a critical need for sorting complex materials, such as pancreatic islets of Langerhans, exocrine acinar tissues, and embryoid bodies. These materials are cell clusters, which have highly heterogeneous physical properties (such as size, shape, morphology, and deformability). Selecting such materials on the basis of specific properties can i...
Vitrification‐based cryopreservation is a promising approach to achieving long‐term storage of biological systems for maintaining biodiversity, healthcare, and sustainable food production. Using the “cryomesh” system achieves rapid cooling and rewarming of biomaterials, but further improvement in cooling rates is needed to increase biosystem viabil...
A difficult decision for patients in need of kidney-pancreas transplant is whether to seek a living kidney donor or wait to receive both organs from one deceased donor. The framework of dynamic treatment regimes (DTRs) can inform this choice, but a patient-relevant strategy such as "wait for deceased-donor transplant" is ill-defined because there a...
Vitrification could enable long-term organ preservation, but only after loading high-concentration, potentially toxic cryoprotective agents (CPAs) by perfusion. In this paper, we combine a two-compartment Krogh cylinder model with a toxicity cost function to theoretically optimize the loading of CPA (VMP) in rat kidneys as a model system. First, ba...
Banking cryopreserved organs could transform transplantation into a planned procedure that more equitably reaches patients regardless of geographical and time constraints. Previous organ cryopreservation attempts have failed primarily due to ice formation, but a promising alternative is vitrification, or the rapid cooling of organs to a stable, ice...
Organ transplantation remains the only treatment option for patients with end-stage organ failure. The last decade has seen a flurry of activity in improving organ preservation technologies, which promise to increase utilization in a dramatic fashion. They also bring the promise of extending the preservation duration significantly, which opens the...
Laparoscopic donor nephrectomy (LDN) offers advantages to the donor. The reported incidence of testicular pain after LDN varies in the literature ranging from 3% to 55%.
Methods:
A survey was sent to 322 male LDN patients who donated from February 5, 2009, to February 5, 2019. The survey assessed if the donor had testicular pain or saw an additio...
Liver cryopreservation has the potential to enable indefinite organ banking. This study investigated vitrification—the ice-free cryopreservation of livers in a glass-like state—as a promising alternative to conventional cryopreservation, which uniformly fails due to damage from ice formation or cracking. Our unique “nanowarming” technology, which i...
Pancreatic islet transplantation can cure diabetes but requires accessible, high-quality islets in sufficient quantities. Cryopreservation could solve islet supply chain challenges by enabling quality-controlled banking and pooling of donor islets. Unfortunately, cryopreservation has not succeeded in this objective, as it must simultaneously provid...
Introduction. Solid organ transplant graft-versus-host disease (SOT-GVHD) is a rare phenomenon in which recipients of solid organ transplant develop GVHD due to the presence of donor lymphocytes in the graft. SOT-GVHD most often occurs in patients receiving small bowel or liver transplants. Diagnosis is typically via identification of lymphocytic i...
To extend the preservation of donor hearts beyond the current 4–6 h, this paper explores heart cryopreservation by vitrification—cryogenic storage in a glass‐like state. While organ vitrification is made possible by using cryoprotective agents (CPA) that inhibit ice during cooling, failure occurs during convective rewarming due to slow and non‐unif...
The superior death-censored graft survival of the pancreas allograft in simultaneous pancreas kidney transplants (SPK) over pancreas alone transplants (PTA) has long been recognized. Using data from the Scientific Registry of Transplant Recipients (SRTR) and a high-volume pancreas transplant program, we investigated the possible protective role of...
Vitrification can dramatically increase the storage of viable biomaterials in the cryogenic state for years. Unfortunately, vitrified systems ≥3 mL like large tissues and organs, cannot currently be rewarmed sufficiently rapidly or uniformly by convective approaches to avoid ice crystallization or cracking failures. A new volumetric rewarming techn...
Although cellular transplantation remains a relatively small field compared to solid-organ transplantation, the prospects for advancement in basic science and clinical care remain bountiful. In this review, notable historical events and the current landscape of the field of cellular transplantation are reviewed with an emphasis on islets (allo- and...
Introduction
Kidney transplantation (KT) demands that patients navigate a complex healthcare system and adhere to lifelong therapy and surveillance. Cultural and linguistic discordance between patients and providers has been identified as a barrier to successful KT. We studied KT outcomes and disparities among a native Somali population living in M...
Cryopreserved tissues are increasingly needed in biomedical applications. However, successful cryopreservation is generally only reported for thin tissues (≤1 mm). This work presents several innovations to reduce cryoprotectant (CPA) toxicity and improve tissue cryopreservation, including 1) improved tissue warming rates through radiofrequency meta...
*Purpose: There is limited data on trends of early graft loss within 90 days (EGL). Pancreas donor risk index (PDRI) is a scale of pancreas allograft quality that was developed to predict pancreas outcomes at one year. We sought to delineate the trends of pancreas EGL and examine the PDRI predictability of allograft loss and mortality at 90 days in...
Complications associated with bladder-drained pancreata necessitating enteric conversion are common. Data on the outcomes after enteric conversion are conflicting. We studied the association between enteric conversion and the pancreas graft rejection, loss, and mortality.
Methods:
At our center, 1117 pancreas transplants were performed between 20...
Cryopreservation technology allows long‐term banking of biological systems. However, a major challenge to cryopreserving organs remains in the rewarming of large volumes (>3 mL), where mechanical stress and ice formation during convective warming cause severe damage. Nanowarming technology presents a promising solution to rewarm organs rapidly and...
The liver has unique regenerative properties that make it an ideal target for regenerative medicine applications. Hepatic systems are functional subunits of the liver and include hepatocytes, liver organoids, precision cut liver slices (PCLS), liver segments/lobes, and whole organs. Each has particular role in research, diagnostic, and therapeutic...
Kidney transplantation entails well‐coordinated complex care delivery. Patient‐provider cultural and linguistic discordance can lead to healthcare disparities. We analyzed kidney transplantation outcomes among our institution's Hmong recipients using a retrospective cohort study.
From 1995‐2015, 2,164 adult (age >18) recipients underwent kidney tra...
Single‐center studies have demonstrated regional organ procurement collaboration to reduce travel redundancy and improve procurement efficiency. We studied deceased donor kidney, liver, and pancreas transplants performed in the U.S. between 2002 and 2014 using the Scientific Registry of Transplant Recipients (SRTR). We compared graft failure (GF),...
Background:
KT recipients have increased the risk of CVD. The incidence of post-transplant CVEs among pediatric recipients has not been well-characterized.
Patients and methods:
Between 1963 and 2015, 884 pediatric (age: 0-17 years old) recipients received 1058 KTs at our institution. The cumulative incidence of CVEs was analyzed. Statistical mo...
Background:
An elevated body mass index (>30 kg/m2) has been a relative contraindication for living kidney donation; however, such donors have become more common. Given the association between obesity and development of diabetes, hypertension, and end-stage renal disease, there is concern about the long-term health of obese donors.
Methods:
Dono...
With increasing organ demand, living kidney donation from older donors (>60‐years‐old) has become more common. Between 1975 and 2014, 3752 donor nephrectomies (DN) were performed at University of Minnesota; 167 (4.5%) were >60‐years‐old Short‐ and long‐term outcomes were compared between contemporaneous >60‐years‐old and <60‐years‐old donors. On un...
Background:
Maximizing pancreas utilization requires a balance between judicious donor selection and transplant center aggressiveness. We sought to determine how such aggressiveness affects transplant outcomes.
Methods:
Using the Scientific Registry of Transplant Recipients, we studied 28 487 deceased-donor adult pancreas transplants. Donor and...
Background:
Recent changes in policies guiding allocation of transplant kidneys are predicted to increase sharing between distant geographic regions. The potential exists for an increase in cold ischemia time (CIT) with resulting increases in delayed graft function (DGF) and transplant-related costs (TRC). We sought to explore the impact of CIT on...
Purpose of review:
The objective of this review is to describe the physical and biological barriers to organ cryopreservation, historic approaches for conventional cryopreservation and evolving techniques for ice-free cryopreservation by vitrification.
Recent findings:
Vitrification is a process whereby a biologic substance is cooled to cryogeni...
Type 1 diabetes (T1D) results from T-cell mediated destruction of insulin producing beta cells. Insulin represents a key self-antigen in disease pathogenesis as recent studies identified proinsulin responding T-cells from inflamed pancreatic islets of recent onset T1D organ donors. These cells respond to an insulin B chain epitope presented by huma...
Arterial fistulas and pseudoaneurysms are rarely described significant arterial complications associated with pancreas transplantation that sometimes present with herald or catastrophic bleeding. We herein describe our institutional case series with a focus on management and outcomes. Of 2256 pancreas transplants, 24 arterial complications were ide...
Recent changes to pancreas graft allocation policy have increased the number of organs available for regional and distant sharing, which results in a corresponding increase in preservation time. We sought to systematically assess the impact of cold ischemia time (CIT) on outcomes posttransplant. A retrospective review of 1,253 pancreas transplants...
Background:
Short- and intermediate-term results have been reported after rapid discontinuation of prednisone (RDP) in kidney transplant recipients. Yet there has been residual concern about late graft failure in the absence of maintenance prednisone.
Methods:
From October 1, 1999, through June 1, 2015, we performed a total of 1553 adult 1st and...
Background:
Post-transplant malignancy (PTM) remains a concern among pediatric kidney transplant (PKT) recipients.
Study design:
Between 1963 and 2015, 884 pediatric (age: 0-17 years old) recipients received 1055 PKTs at our institution. Cox proportional hazards models were constructed to identify risk factors for PTM after PKT with time-to-firs...
UNOS recommends that fellowship-trained surgeons participate in 15 LDN to be considered proficient. ASTS mandates 12 LDN during abdominal transplant surgery fellowship (ATSF). We performed a retrospective intraoperative case analysis to create a risk-adjusted cumulative summation (RACUSUM) model to assess the learning curve (LC) of novice TSF (nTSF...
In order to enhance selection of appropriate deceased donors for pancreas transplants, we sought to determine whether human leukocyte antigen (HLA) matching improved posttransplant outcomes. In this single-center study of 1,219 pancreas transplants we correlated posttransplant outcomes with HLA-A, -B, -C, -DR, and -DQ matches and mismatches. Reject...
Serrano O, Bangdiwala A, Vock D, Kirchner V, Yadav K, Pugalendhi A, Minja E, Dunn T, Finger E, Matas A, Kandaswamy R. Clinical Significance of Solitary Pulmonary Nodules in Liver Transplant Recipients with Hepatocellular Carcinoma. InAMERICAN JOURNAL OF TRANSPLANTATION 2016 Jun 1 (Vol. 16, pp. 461-461). 111 RIVER ST, HOBOKEN 07030-5774, NJ USA: WIL...
Kirchner V, Zhang L, Dunn T, Finger E, Hassan M, Kandaswamy R, Lake J, Liu P, Minja E, Serrano O, Pugalenthi A. Does Pre-Operative Transarterial Chemoembolization (TACE) Increase the Risk of Early Post-Operative Pancreatitis After Liver Transplantation (LT)?. InAMERICAN JOURNAL OF TRANSPLANTATION 2016 Jun 1 (Vol. 16, pp. 669-670). 111 RIVER ST, HOB...
Background:
Living donor segmental pancreas transplants (LDSPTx) have been performed selectively to offer a preemptive transplant option for simultaneous pancreas-kidney recipients and to perform a single operation decreasing the cost of pancreas after kidney transplant. For solitary pancreas transplants, this option historically provided a better...
Serrano O, Bangdiwala A, Vock D, Minja E, Pugalendhi A, Yadav K, Kirchner V, Payne W, Dunn T, Chinnakotla S, Finger E. Evolution of Donor Nephrectomy: Long-Term Outcomes with Four Different Techniques Between 1963 and 2014 at a Single Institution. InAMERICAN JOURNAL OF TRANSPLANTATION 2016 Jun 1 (Vol. 16, pp. 645-645). 111 RIVER ST, HOBOKEN 07030-5...
Introduction:
The development of minimally invasive surgical approaches to donor nephrectomy (DN) has been driven by the potential advantages for the donor, with questions remaining about long-term outcomes.
Methods:
All living DN performed from June 1963 through December 2014 at the University of Minnesota were reviewed. Outcomes were compared...
Pancreas retransplantation is associated with increased rates of technical failure and rejection compared to other organ transplants. As such, it is not routinely done, and outcomes are mostly known through registry data. Here we analyze the outcomes of primary versus retransplant for all pancreas transplants done in our program over nearly 35 year...
Introduction:
Compared with enteric drainage, bladder-drained solitary pancreas transplants can be monitored for rejection by measuring urine amylase levels. However, bladder drainage is associated with a higher risk of infection and metabolic complications, necessitating enteric conversion in about one third of patients. We hypothesized that hype...