Publications by authors named "Arthur Matas"

Background: The limitations of conventional measures of socioeconomic status (SES) limit our ability to elucidate the role of SES as a key element of social determinants of health in kidney transplantation. This study's objective was to use an innovative SES measure, the HOUsing-based SES measure (HOUSES) index, to examine the effects of social determinants of health on access to and outcomes of kidney transplantation.

Methods: Our study included residents of Minnesota (age older than 18 y) who underwent kidney transplantation at a single center between 2010 and 2020.

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Living kidney donation and living liver donation significantly increases organ supply to make lifesaving transplants possible, offering survival benefits to the recipients and cost savings to society. Of all living donors, 40% are women of childbearing age. However, limited data exist regarding the effect of donation on future pregnancies and of pregnancy-related complications on postdonation outcomes.

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Patients are not always aware of listing criteria and offer acceptance across transplant programs. Factors such as age and body mass index can impact access to transplants as centers have different candidate criteria. Therefore, we created a transplant center search tool (transplantcentersearch.

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Article Synopsis
  • The study investigates how competing risks, like allograft failure and death with a functioning graft, affect the performance of prognostic models used for kidney transplant recipients.
  • The research involves 11,046 kidney transplant recipients across 10 countries, developing models using various regression techniques to predict long-term graft failure while carefully evaluating their accuracy and reliability.
  • Results indicate that both standard Cox models and competing risk models provide similar predictions for graft failure, with high concordance indices, confirming their usefulness in clinical settings.
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African American (AA) kidney transplant recipients (KTRs) have poor outcomes, which may in-part be due to tacrolimus (TAC) sub-optimal immunosuppression. We previously determined the common genetic regulators of TAC pharmacokinetics in AAs which were CYP3A5 *3, *6, and *7. To identify low-frequency variants that impact TAC pharmacokinetics, we used extreme phenotype sampling and compared individuals with extreme high (n = 58) and low (n = 60) TAC troughs (N = 515 AA KTRs).

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Article Synopsis
  • Many kidney transplant patients are classified as having no rejection after biopsy, but some may actually have undetected rejection activities.
  • A study of over 5,000 biopsies found that more than half were marked as no rejection, yet many showed signs of subthreshold T cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR).
  • Patients with these hidden rejection activities are at increased risk of future graft issues, as higher levels of TCMR and ABMR correlate with worse kidney function and higher chances of rejection in subsequent biopsies.
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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 1, 1983 and December 31, 2023 at the University of Minnesota were reviewed, including pancreas transplant alone (PTA), simultaneous pancreas-kidney transplants (SPK), and pancreas after kidney transplants (PAK).

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Background: Therapeutic drug monitoring for mycophenolic acid (MPA) is challenging due to difficulties in measuring the area under the curve (AUC). Limited sampling strategies (LSSs) have been developed for MPA therapeutic drug monitoring but come with risk of unacceptable performance. The authors hypothesized that the poor predictive performance of LSSs were due to the variability in MPA enterohepatic recirculation (EHR).

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Aims: Tacrolimus, metabolized by CYP3A4 and CYP3A5 enzymes, is susceptible to drug-drug interactions (DDI). Steroids induce CYP3A genes to increase tacrolimus clearance, but the effect is variable. We hypothesized that the extent of the steroid-tacrolimus DDI differs by CYP3A4/5 genotypes.

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Objective: To describe the evolution of pancreas transplantation, including improved outcomes and factors associated with improved outcomes over the past 5 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 carefully assess the current state of pancreas transplantation to determine its ongoing role in patient care.

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Living kidney donors make a significant contribution to alleviating the organ shortage. The aim of this article is to provide an overview of mid- and long-term (≥12 mo) living donor psychosocial outcomes and highlight areas that have been understudied and should be immediately addressed in both research and clinical practice. We conducted a narrative review by searching 3 databases.

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In the general population, decreases in glomerular filtration rate (GFR) are associated with subsequent development of chronic kidney disease (CKD), cardiovascular disease (CVD), and death. It is unknown if low estimated GFR (eGFR) before or early after kidney donation was also associated with these risks. One thousand six hundred ninety-nine living donors who had both predonation and early (4-10 weeks) postdonation eGFR were included.

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In a previous study, we observed decreased 1,25-dihydroxyvitamin D levels, secondary hyperparathyroidism, and increased bone turnover markers in living kidney donors (LKDs) at 3 months and 36 months after kidney donation. In our recent survey-based study, we found no increased risk of fractures of all types but observed significantly more vertebral fractures in LKDs compared with matched controls. To elucidate the long-term effects of kidney donation on bone health, we recruited 139 LKDs and 139 age and sex matched controls from the survey-based participants for further mechanistic analyses.

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Background: Acute rejection (AR) after kidney transplantation is an important allograft complication. To reduce the risk of post-transplant AR, determination of kidney transplant donor-recipient mismatching focuses on blood type and human leukocyte antigens (HLA), while it remains unclear whether non-HLA genetic mismatching is related to post-transplant complications.

Methods: We carried out a genome-wide scan (HLA and non-HLA regions) on AR with a large kidney transplant cohort of 784 living donor-recipient pairs of European ancestry.

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Background: Valganciclovir (valG), a cytomegalovirus (CMV) prophylactic agent, has dose-limiting side effects. The tolerability and effectiveness of valacyclovir (valA) as CMV prophylaxis is unknown.

Methods: We conducted a randomized, open-label, single-center trial of valA versus valG for all posttransplant CMV prophylaxis in adult and pediatric kidney recipients.

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African American (AA) kidney transplant recipients (KTRs) have poor outcomes, which may in-part be due to tacrolimus (TAC) sub-optimal immunosuppression. We previously determined the common genetic regulators of TAC pharmacokinetics in AAs which were CYP3A5 *3, *6, and *7. To identify low-frequency variants that impact TAC pharmacokinetics, we used extreme phenotype sampling and compared individuals with extreme high (n=58) and low (n=60) TAC troughs (N=515 AA KTRs).

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The human microbiome is associated with human health and disease. Exogenous compounds, including pharmaceutical products, are also known to be affected by the microbiome, and this discovery has led to the field of pharmacomicobiomics. The microbiome can also alter drug pharmacokinetics and pharmacodynamics, possibly resulting in side effects, toxicities, and unanticipated disease response.

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Importance: Living kidney donors may have an increased risk of fractures due to reductions in kidney mass, lower concentrations of serum 1,25-dihydroxyvitamin D, and secondary increases in serum parathyroid hormone.

Objective: To compare the overall and site-specific risk of fractures among living kidney donors with strictly matched controls from the general population who would have been eligible to donate a kidney but did not do so.

Design, Setting, And Participants: This survey study was conducted between December 1, 2021, and July 31, 2023.

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Article Synopsis
  • * A recent symposium brought together experts to discuss ways to improve living kidney donation, focusing on ethical considerations around donor compensation and the potential benefits, such as saving lives and reducing taxpayer costs.
  • * Consensus among the discussants pointed to the need for removing barriers in the donor evaluation process, promoting living donor chains, ensuring donor safety, and covering any costs incurred by donors to enhance donation rates.
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Background: Early in the history of kidney transplantation, short-term graft survival was low. Yet some have had excellent long-term survival. Herein, we describe characteristics of pediatric recipients with > 40 years of graft survival currently alive with a functioning first graft.

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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 are multiple versions of treatment (i.e.

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Objective: To compare the performance of a newly developed race-free kidney recipient specific glomerular filtration rate (GFR) equation with the three current main equations for measuring GFR in kidney transplant recipients.

Design: Development and validation study SETTING: 17 cohorts in Europe, the United States, and Australia (14 transplant centres, three clinical trials).

Participants: 15 489 adults (3622 in development cohort (Necker, Saint Louis, and Toulouse hospitals, France), 11 867 in multiple external validation cohorts) who received kidney transplants between 1 January 2000 and 1 January 2021.

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Background: There is uncertainty about the long-term risks of living kidney donation. Well-designed studies with controls well-matched on risk factors for kidney disease are needed to understand the attributable risks of kidney donation.

Methods: The goal of the Minnesota Attributable Risk of Kidney Donation (MARKD) study is to compare the long-term (> 50 years) outcomes of living donors (LDs) to contemporary and geographically similar controls that are well-matched on health status.

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