Life after pancreas transplantation: reversal of diabetic lesions

Four Decades of Research Productivity and Hot Spots in Pancreas Transplantation

Background: The field of pancreas transplantation has undergone transformative phases, progressing from its promising inception in 1966 to becoming a standard treatment for patients with insulin-dependent diabetes. This bibliometric analysis explores the progression of pancreas transplantation research over a period of four decades, mapping milestones, contributors, and emerging trends. Methods: Our bibliometric analysis utilizes the comprehensive Scopus database, which includes publication titles, author information, affiliations, abstracts, keywords, and journal details. The search strategy was centered on research related to pancreas and pancreas-kidney transplantation. The analysis encompasses the time frame spanning from 1983 to 2023, with the data extraction taking place on October 7th, 2023. Results: The analysis of 4,897 articles uncovered unique trends in the field of pancreas transplantation research. The years 1989, 1996, and 2021 saw significant increases in the number of publications, which corresponded to the responses to clinical challenges and advancements. Contributions by authors from the United States of America were the most numerous, with 1,905 publications and 49,949 citations. The research topics were highlighted by keywords such as "graft survival," "graft rejection," and" Immunosuppressive treatment." Conclusion: The fluctuations in publication trends that have been identified indicate dynamic reactions to changing priorities and challenges. Although it has limitations, this analysis provides valuable insights for researchers, clinicians, and policymakers who are dealing with the complex field of pancreas transplantation literature. Further bibliometric research may advance our knowledge and direct future initiatives in this developing field.

Pancreas Transplantation: Current Challenges, Considerations, and Controversies

Pancreas transplantation (PTx) reestablishes an autoregulating source of endogenous insulin responsive to normal feedback controls. In addition to achieving complete β-cell replacement that frees the patient with diabetes from the need to monitor serum glucose and administer exogenous insulin, successful PTx provides counterregulatory hormone secretion and exocrine function. A functioning PTx mitigates glycemic variability, eliminates the daily stigma and burden of diabetes, restores normal glucose homeostasis in patients with complicated diabetes, and improves quality of life and life expectancy. The tradeoff is that it entails a major surgical procedure and requisite long-term immunosuppression. Despite the high likelihood of rendering patients euglycemic independent of exogenous insulin, PTx is considered a treatment rather than a cure. In spite of steadily improving outcomes in each successive era coupled with expansion of recipient selection criteria to include patients with a type 2 diabetes phenotype, a decline in PTx activity has occurred in the new millennium related to a number of factors including: (1) lack of a primary referral source and general acceptance by the diabetes care community; (2) absence of consensus criteria; and (3) access, education, and resource issues within the transplant community. In the author's experience, patients who present as potential candidates for PTx have felt as though they needed to circumvent the conventional diabetes care model to gain access to transplant options. PTx should be featured more prominently in the management algorithms for patients with insulin requiring diabetes who are failing exogenous insulin therapy or experiencing progressive diabetic complications regardless of diabetes type. Furthermore, all patients with diabetes and chronic kidney disease should undergo consideration for simultaneous pancreas-kidney transplantation independent of geography or location.

Comprehensive review: Frailty in pancreas transplant candidates and recipients

Well-selected patients with kidney disease and diabetes mellitus who undergo simultaneous kidney-pancreas transplantation often experience dramatic improvements in quality of life and long-term survival compared to those who remain on medical therapy. Over the past several years the importance of frailty in the pancreas transplant candidate and recipient populations has grown. More patients with advanced age have entered the waitlist, and complications from prolonged diabetes, even in younger patients, have created increased evidence of risk for frailty. Given these concerns, and the broad challenges facing pancreas transplantation volumes overall, we generated this review to help establish the impact and implications. We summarize the interplay of immunological factors, aging, environmental factors, diabetes mellitus, and chronic kidney disease that put these patients at risk for frailty. We discuss its measurement and recommend a combination of two instruments (both well-validated and one entirely objective). We describe the outcomes for patients before and after pancreas transplantation who may have frailty, and what interventions can be taken to mitigate its effects. Broader investigation into frailty in the pancreas transplant population is needed to better understand how to select patients for pancreas transplantation and to how manage its consequences thereafter.

Modern indications for referral for kidney and pancreas transplantation

PURPOSE OF REVIEW

Pancreas transplantation (PTx) is currently the only therapy that can predictably achieve sustained euglycemia independent of exogenous insulin administration in patients with insulin-dependent diabetes mellitus. This procedure involves a complex abdominal operation and lifetime dependence on immunosuppressive medications. Therefore, PTx is most frequently performed in combination with other organs, usually a kidney transplant for end stage diabetic nephropathy. Less frequently, solitary PTx may be indicated in patients with potentially life-threatening complications of diabetes mellitus. There remains confusion and misperceptions regarding indications and timing of patient referral for PTx.

RECENT FINDINGS

In this review, the referral, evaluation, and listing process for PTx is described, including a detailed discussion of candidate assessment, indications, contraindications, and outcomes.

SUMMARY

Because the progression of diabetic kidney disease may be less predictable than other forms of kidney failure, early referral for planning of renal and/or pancreas transplantation is paramount to optimize patient care and allow for possible preemptive transplantation.

Pancreas Transplantation in Minorities including Patients with a Type 2 Diabetes Phenotype

Background: Prior to year 2000, the majority of pancreas transplants (PTx) were performed as simultaneous pancreas-kidney transplants (SPKTs) in Caucasian adults with end stage renal failure secondary to type 1 diabetes mellitus (T1DM) who were middle-aged. In the new millennium, improving outcomes have led to expanded recipient selection that includes patients with a type 2 diabetes mellitus (T2DM) phenotype, which excessively affects minority populations. Methods: Using PubMed® to identify appropriate citations, we performed a literature review of PTx in minorities and in patients with a T2DM phenotype. Results: Mid-term outcomes with SPKT in patients with uremia and circulating C-peptide levels (T2DMphenotype) are comparable to those patients with T1DM although there may exist a selection bias in the former group. Excellent outcomes with SPKT suggests that the pathophysiology of T2DM is heterogeneous with elements consisting of both insulin deficiency and resistance related to beta-cell failure. As a result, increasing endogenous insulin (Cp) production following PTx may lead to freedom checking blood sugars or taking insulin, better metabolic counter-regulation, and improvements in quality of life and life expectancy compared to other available treatment options. Experience with solitary PTx for T2DM or in minorities is limited but largely mirrors the trends reported in SPKT. Conclusions: PTx is a viable treatment option in patients with pancreas endocrine failure who are selected appropriately regardless of diabetes type or recipient race. This review will summarize data that unconventional patient populations with insulin-requiring diabetes may gain value from PTx with an emphasis on contemporary experiences and appropriate selection in minorities in the new millennium.

Impact of Functional Status on Outcomes of Simultaneous Pancreas-kidney Transplantation: Risks and Opportunities for Patient Benefit

Background.

The impact of functional status on survival among simultaneous pancreas-kidney transplant (SPKT) candidates and recipients is not well described.

Methods.

We examined national Scientific Registry of Transplant Recipients (SRTR) data for patients listed for SPKT in the United States (2006–2019). Functional status was categorized by center-reported Karnofsky Performance Score (KPS). We used Cox regression to quantify associations of KPS at listing and transplant with subsequent patient survival, adjusted for baseline patient and transplant factors (adjusted hazard ratio, _{95% LCL}aHR_95%UCL). We also explored time-dependent associations of SPKT with survival risk after listing compared with continued waiting in each functional status group.

Results.

KPS distributions among candidates (N = 16 822) and recipients (N = 10 316), respectively, were normal (KPS 80–100), 62.0% and 57.8%; capable of self-care (KPS 70), 23.5% and 24.7%; requires assistance (KPS 50–60), 12.4% and 14.2%; and disabled (KPS 10–40), 2.1% and 3.3%. There was a graded increase in mortality after listing and after transplant with lower functional levels. Compared with normal functioning, mortality after SPKT rose progressively for patients capable of self-care (aHR, _1.001.18_1.41), requiring assistance (aHR, _1.061.31_1.60), and disabled (aHR, _1.101.55_2.19). In time-dependent regression, compared with waiting, SPKT was associated with 2-fold mortality risk within 30 days of transplant. However, beyond 30 days, SPKT was associated with reduced mortality, from 52% for disabled patients (aHR, _0.260.48_0.88) to 70% for patients with normal functioning (aHR, _0.260.30_0.34).

Conclusions.

While lower functional status is associated with increased mortality risk among SPKT candidates and recipients, SPKT can provide long-term survival benefit across functional status levels in those selected for transplant.

Quantification of pancreatic elasticity in type 2 diabetes: A new potential imaging marker for evaluation of microangiopathy

PURPOSE

The aim of this study was to noninvasively explore pancreatic morphological and mechanical changes in diabetic patients with or without microangiopathy and to investigate the clinical correlations of pancreatic stiffness or size with diabetic microangiopathy.

METHODS

A total of 213 type 2 diabetic patients with / without microangiopathy (91/122) were prospectively enrolled. Microangiopathy included diabetic retinopathy, diabetic nephropathy and diabetic peripheral neuropathy. Each subject underwent pancreatic ultrasonography and elastography. The shear wave velocity (SWV) and thickness of the head, body and tail were measured and compared. Receiver operating characteristic (ROC) curves was performed in the diagnosis of microangiopathy. Risk factors of the occurrence of more microvascular complications were explored.

RESULTS

The SWV in pancreas increased significantly in patients with microangiopathy (P < 0.01) while the thickness was similar in all patients. The area under ROC curve for the SWV in pancreatic body was greatest (0.747) and the sensitivity, specificity were 73.0, 70.9 %. There was a significant shift towards the occurrence of more microvascular complications for patients with increasing of the SWV in pancreatic body (OR 39.25), long duration of diabetes (OR 1.077), aging (OR 1.039) and elevation of microalbuminuria (OR 1.004).

CONCLUSIONS

The SWV in pancreatic body was significantly high in diabetic patients with microangiopathy and was prominently correlated with the number of microvascular complications. The SWV in pancreatic body may be considered as a potential marker for diabetic microangiopathy and its occurrence.

Reseeding endothelial cells with fibroblasts to improve the re-endothelialization of pancreatic acellular scaffolds

Pancreatic transplantation remains the only cure for diabetes, but the shortage of donors limits its clinical application. Whole organ decellularized scaffolds offer a new opportunity for pancreatic organ regeneration; however inadequate endothelialization and vascularization can prevent sufficient transport of oxygen and nutrient supplies to the transplanted organ, as well as leading unwanted thrombotic events. In the present study, we explored the re-endothelialization of rat pancreatic acellular scaffolds via circulation perfusion using human skin fibroblasts (FBs) and human umbilical vein endothelial cells (HUVECs). Our results revealed that the cell adhesion rate when these cells were co-cultured was higher than under control conditions, and this increase was associated with increased release of growth factors including VEGF, FGFb, EGF, and IGF-1 as measured by ELISA. When these recellularized organs were implanted in vivo for 28 days in rat dorsal subcutaneous pockets, we found that de novo vasculature formation in the co-culture samples was superior to the control samples. Together these results suggest that endothelial cell and FB co-culture enhances the re-endothelialization and vascularization of pancreatic acellular scaffolds.

Pancreas Transplantation for Patients with Type 1 and Type 2 Diabetes Mellitus in the United States: A Registry Report

Successful pancreas transplantation is still the only method to restore short-term and long-term insulin independence and good metabolic control for patients with diabetes. Since the first transplant in 1966, tremendous progress in outcome was made; however, transplant numbers have declined since 2004. This article describes the development and risk factors of pancreas transplantation with or without a kidney graft between 2001 and 2016. Patient survival and graft function improved significantly owing to careful recipient and donor selection, which reduced technical failure and immunologic graft loss rates.

Transplantation of human fetal pancreatic progenitor cells ameliorates renal injury in streptozotocin-induced diabetic nephropathy

Background

Diabetic nephropathy (DN) is a severe complication of diabetes mellitus (DM). Pancreas or islet transplantation has been reported to prevent the development of DN lesions and ameliorate or reverse existing glomerular lesions in animal models. Shortage of pancreas donor is a severe problem. Islets derived from stem cells may offer a potential solution to this problem.

Objective

To evaluate the effect of stem cell-derived islet transplantation on DN in a rat model of streptozotocin-induced DM.

Methods

Pancreatic progenitor cells were isolated from aborted fetuses of 8 weeks of gestation. And islets were prepared by suspension culture after a differentiation of progenitor cells in medium containing glucagon-like peptide-1 (Glp-1) and nicotinamide. Then islets were transplanted into the liver of diabetic rats via portal vein. Blood glucose, urinary volume, 24 h urinary protein and urinary albumin were measured once biweekly for 16 weeks. Graft survival was evaluated by monitoring human C-peptide level in rat sera and by immunohistochemical staining for human mitochondrial antigen and human C-peptide in liver tissue. The effect of progenitor-derived islets on filtration membrane was examined by electron microscopy and real-time polymerase chain reaction (PCR). Immunohistochemical staining, real-time PCR and western blot were employed for detecting fibronectin, protein kinase C beta (PKCβ), protein kinase A (PKA), inducible nitric oxide synthase (iNOS) and superoxide dismutase (SOD).

Results

Islet-like clusters derived from 8th gestational-week human fetal pancreatic progenitors survived in rat liver. And elevated serum level of human C-peptide was detected. Blood glucose, 24 h urinary protein and urinary albumin were lower in progenitor cell group than those in DN or insulin treatment group. Glomerular basement membrane thickness and fibronectin accumulation decreased significantly while podocytes improved morphologically in progenitor cell group. Furthermore, receptor of advanced glycation end products and PKCβ became down-regulated whereas PKA up-regulated by progenitor cell-derived islets. And iNOS rose while SOD declined.

Conclusions

DN may be reversed by transplantation of human fetal pancreatic progenitor cell-derived islets. And fetal pancreatic progenitor cells offer potential resources for cell replacement therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1253-1) contains supplementary material, which is available to authorized users.

Pancreas Transplantation: An Alarming Crisis in Confidence

In the past decade, the annual number of pancreas transplantations performed in the United States has steadily declined. From 2004 to 2011, the overall number of simultaneous pancreas-kidney (SPK) transplantations in the United States declined by 10%, whereas the decreases in pancreas after kidney (PAK) and pancreas transplant alone (PTA) procedures were 55% and 34%, respectively. Paradoxically, this has occurred in the setting of improvements in graft and patient survival outcomes and transplanting higher-risk patients. Only 11 centers in the United States currently perform ≥20 pancreas transplantations per year, and most centers perform <5 pancreas transplantations annually; many do not perform PAKs or PTAs. This national trend in decreasing numbers of pancreas transplantations is related to a number of factors including lack of a primary referral source, improvements in diabetes care and management, changing donor and recipient considerations, inadequate training opportunities, and increasing risk aversion because of regulatory scrutiny. A national initiative is needed to "reinvigorate" SPK and PAK procedures as preferred transplantation options for appropriately selected uremic patients taking insulin regardless of C-peptide levels or "type" of diabetes. Moreover, many patients may benefit from PTAs because all categories of pancreas transplantation are not only life enhancing but also life extending procedures.