Donor risk factors in pancreas transplantation

Pancreatic Differentiation of Oral Minor Salivary Gland Stem Cells

INTRODUCTION

Stem cells from various sources including major salivary glands have been used to establish pancreatic differentiation in an attempt to provide new treatment options for patients with diabetes mellitus. In contrast, the potential of using the more easily accessible intraoral minor salivary glands has not been evaluated so far.

MATERIALS AND METHODS

Salivary stem cells were isolated from normal labial minor salivary glands that were removed during the excision of a mucocele and were attempted to differentiate into pancreatic cell lines using a culture medium enriched with activin A, retinoic acid and GLP-1.Real time RT-PCR was used to evaluate the expression of the genes of pancreatic transcription factors MafA, Ptf1a, Hb9 and Arx. Complementary, 22 labial minor salivary gland paraffin-embedded specimens were examined using immunohistochemistry for the presence of the relevant gene products of the pancreatic transcription factors Arx, MafA, Ptf1a and Pdx1.

RESULTS

The differentiated salivary stem cells(cells of passage 3) expressed the genes of the pancreatic transcription factors MafA, Ptf1a, Hb9 and Arx even on the first day of the experiment while immunohistochemistry also confirmed the presence of the protein products of Arx, MafA, Ptf1a as well as Pdx1[> 50% of the specimens for Arx(5/8) and MafA(7/8), < 50% for Ptf1a(5/11) and Pdx1(5/11)] in ducts, mesenchymal connective tissue and acinar cells.

CONCLUSIONS

Labial minor salivary glands may share gene and protein characteristics with pancreas suggesting a possible usefulness for pancreatic regeneration or substitution in cases of deficiency.

Outcome-Orientated Organ Allocation-A Composite Risk Model for Pancreas Graft Evaluation and Acceptance

Background: Pancreas transplantation (PTX) remains the most effective treatment to prevent long-term complications and provide consistent euglycemia in patients with endocrine pancreatic insufficiency, mainly in type I diabetic patients. Considering early graft loss (EGL) and the perioperative complication rate, an optimal risk stratification based on donor risk factors is paramount. Methods: In our single-center study, we retrospectively assessed the risk factors for EGL and reduced graft survival in 97 PTXs (82 simultaneous pancreas and kidney [SPK], 11 pancreases transplanted after kidney [PAK] and 4 pancreases transplanted alone [PTA]) between 2010 and 2021. By statistically analyzing the incorporation of different donor risk factors using the Kaplan-Meier method and a log-rank test, we introduced a composite risk model for the evaluation of offered pancreas grafts. Results: The overall EGL rate was 6.5%. In the univariate analysis of donor characteristics, age > 45 years, BMI > 25 kg/m2, lipase > 60 U/L, cerebrovascular accident (CVA) as the cause of death, mechanical cardiopulmonary resuscitation (mCPR), cold ischemia time (CIT) > 600 min and retrieval by another center were identified as potential risk factors; however, they lacked statistical significance. In a multivariate model, age > 45 years (HR 2.05, p = 0.355), BMI > 25 kg/m2 (HR 3.18, p = 0.051), lipase > 60 U/L (HR 2.32, p = 0.148), mCPR (HR 8.62, p < 0.0001) and CIT > 600 min (HR 1.89, p = 0.142) had the greatest impact on pancreas graft survival. We subsumed these factors in a composite risk model. The combination of three risk factors increased the rate of EGL significantly (p = 0.003). Comparing the pancreas graft survival curves for ≥3 risk factors to <3 risk factors in a Kaplan-Meier model revealed significant inferiority in the pancreas graft survival rate (p = 0.029). Conclusions: When evaluating a potential donor organ, grafts with a combination of three or more risk factors should only be accepted after careful consideration to reduce the risk of EGL and to significantly improve outcomes after PTX.

Poor utilization of deceased donor pancreata in the United States: Time for action

The number of solid organ pancreas transplants performed in the United States has declined over the past two decades despite improving outcomes and the known benefits associated with this procedure. Although the reasons are multifactorial, high rates of deceased donor pancreata nonrecovery and nonuse have at least in part contributed to the reduction in pancreas transplant activity. The pancreas has higher nonrecovery and nonuse rates compared to the kidney and liver because of more stringent donor selection criteria, particularly with respect to donor age and body mass index, although even marginally inferior donor pancreata likely still benefit some patients compared to alternative therapies. In this editorial, we present several donor-, candidate-, and center-specific factors that are either confirmed or suspected of being associated with inferior outcomes, which contribute to high pancreas nonrecovery and nonuse rates. In addition, we have discussed several measures to increase pancreas recovery and reduce pancreas nonutilization.

An Examination of Donor Factors That Impact the Results of the Glucagon Stimulation Test as an Assessment of the Pancreatic Graft Endocrine Function

OBJECTIVES

Delta C-peptide derived by the glucagon stimulation test is a reliable value for the evaluation of the pancreatic endocrine function after pancreas transplantation. We examined the associations between delta C-peptide as pancreatic graft endocrine function and donor background factors.

METHODS

Sixty-five cases of pancreatic transplantation from brain-dead donors, which were performed in our facility, were enrolled in this study. Enrolled recipients underwent a glucagon stimulation test within 1 to 3 months after transplantation to evaluate the pancreatic graft endocrine function with delta C-peptide to compare donor background factors.

RESULTS

The following factors were associated with significant deterioration of the delta C-peptide: age of 50 years or greater, death from cerebrovascular accident, hemoglobin A1c level of 5.6% or greater, creatinine level of 1.0 mg/dL or greater, C-reactive protein level of 25 mg/dL or greater, and sodium level of 150 mmol/L or greater. In addition, increased numbers of these donor factors indicated significantly greater deterioration of the posttransplant pancreatic endocrine function ( P < 0.001).

CONCLUSIONS

To secure insulin independence after pancreas transplantation, which means maintaining a delta C-peptide level of 1.0 ng/mL or greater on a glucagon stimulation test, the utilization of donors, who possesses more than equal to 3 of the donor factors identified in this study, should be carefully considered.

Influence of Intraoperative Hemodynamic Parameters on Outcome in Simultaneous Pancreas-Kidney Transplant Recipients

Objectives: Adequate organ perfusion, as well as appropriate blood pressure levels at the time of unclamping, is crucial for early and long-term graft function and outcome in simultaneous pancreas−kidney transplantation (SPKT). However, the optimal intraoperative mean arterial pressure (MAP) level has not well been defined. Methods: From a prospectively collected database, the medical data of 105 patients undergoing SPKT at our center were retrospectively analyzed. A receiver operating characteristic (ROC) analysis was preliminarily performed for optimal cut-off value for MAP at reperfusion, to predict early pancreatic graft function. Due to these results, we divided the patients according to their MAP values at reperfusion into <91 mmHg (n = 47 patients) and >91 mmHg (n = 58 patients) groups. Clinicopathological characteristics and outcomes, as well as early graft function and long-term survival, were retrospectively analyzed. Results: Donor and recipient characteristics were comparable between both groups. Rates of postoperative complications were significantly higher in the <91 mmHg group than those in the >91 mmHg group (vascular thrombosis of the pancreas: 7 (14%) versus 2 (3%); p = 0.03; pancreatitis/intraabdominal abscess: 10 (21%) versus 4 (7%); p = 0.03; renal delayed graft function (DGF): 11 (23%) versus 5 (9%); p = 0.03; postreperfusion urine output: 106 ± 50 mL versus 195 ± 45 mL; p = 0.04). There were no significant differences in intraoperative volume repletion, central venous pressure (CVP), use of vasoactive inotropic agents, and the metabolic outcome. Five-year pancreas graft survival was significantly higher in the >91 mmHg group (>91 mmHg: 82% versus <91 mmHg: 61%; p < 0.01). No significant differences were observed in patient and kidney graft survival at 5 years between both groups. Multivariate Cox regression analysis affirmed MAP < 91 mmHg as an independent prognostic predictor for renal DGF (HR 3.49, 1.1−10.8, p = 0.03) and pancreas allograft failure (HR 2.26, 1.0−4.8, p = 0.01). Conclusions: A MAP > 91 mmHg at the time point of reperfusion was associated with a reduced rate of postoperative complications, enhancing and recovering long-term graft function and outcome and thus increasing long-term survival in SPKT recipients.