Pancreatic transplantation for patients with Type I diabetes

Alginate-Poly[2-(methacryloyloxy)ethyl]trimethylammonium Chloride (PMETAC) Immunoisolating Capsules Prolong the Viability of Pancreatic Islets In Vivo

BACKGROUND/OBJECTIVES

This study focuses on the development and evaluation of novel alginate-poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC) microcapsules for encapsulating pancreatic islets to address insulin deficiency in diabetes.

METHODS

In previous research, we fabricated and characterized PMETAC microcapsules, evaluating their stability and permeability in vitro. This study further probes the capsules in vivo, focusing on the functional activity of the encapsulated islets post-transplantation, their viability extension, and the assessment of the immunoprotective, antifibrotic properties, and biostability of the capsules.

RESULTS

Rabbit-derived islets were encapsulated and transplanted into diabetic rats. The encapsulated islets maintained insulin secretion for up to 90 days, significantly longer than non-encapsulated ones, which ceased functioning after 7 days. Histological analysis demonstrated high biocompatibility of the PMETAC coating, resulting in minimal fibrotic overgrowth around the capsules.

CONCLUSIONS

The study highlights the critical role of immunoprotection and the tendency to reduce fibrosis in prolonging islet function. These findings suggest that PMETAC-coated capsules offer a promising solution for cell-based therapies in diabetes by improving graft longevity and reducing fibrotic overgrowth.

Development and validation of a prognostic model for kidney function 1 year after combined pancreas and kidney transplantation using pre-transplant donor and recipient variables

Purpose

The widening gap between demand and supply of organs for transplantation provides extraordinary challenges for ethical donor organ allocation rules. The transplant community is forced to define favorable recipient/donor combinations for simultaneous kidney-pancreas transplantation. The aim of this study is the development of a prognostic model for the prediction of kidney function 1 year after simultaneous pancreas and kidney transplantation using pre-transplant donor and recipient variables with subsequent internal and external validation.

Methods

Included were patients with end-stage renal failure due to diabetic nephropathy. Multivariable logistic regression modeling was applied for prognostic model design with retrospective data from Hannover Medical School, Germany (01.01.2000–31.12.2011) followed by prospective internal validation (01 Jan. 2012–31 Dec. 2015). Retrospective data from another German transplant center in Kiel was retrieved for external model validation via the initially derived logit link function.

Results

The developed prognostic model is able to predict kidney graft function 1 year after transplantation ≥ KDIGO stage III with high areas under the receiver operating characteristic curve in the development cohort (0.943) as well as the internal (0.807) and external validation cohorts (0.784).

Conclusion

The proposed validated model is a valuable tool to optimize present allocation rules with the goal to prevent transplant futility. It might be used to support donor organ acceptance decisions for individual recipients.

Electronic supplementary material

The online version of this article (10.1007/s00423-018-1712-z) contains supplementary material, which is available to authorized users.

Polymeric Materials for Perm-Selective Coating of Alginate Microbeads

Application of microencapsulation to the immunoisolation of pancreatic islets holds promise for expanding the use of islet transplantation as a treatment option for Type 1 diabetes. It is generally believed that successful development of a reliable methodology will ideally allow for transplantation of pancreatic islets that are protected from the immune system, thereby obviating the need for the use of immunosuppressive drugs and their attendant side effects. In addition, this technology has the potential to expand the donor pool as islets from nonhuman donors could be used as xenografts in human patients. The complex polysaccharide, alginate, has been the most widely used polymer for microencapsulation of islets. However, it is known that alginate lacks appreciable permselectivity to confer immunoisolation of encapsulated islets, thus necessitating the routine permselective coating of alginate microbeads with polymers of amino acids, mainly, poly-L-lysine (PLL) and poly-L-ornithine (PLO). The protocol described in this chapter outlines the steps we have used in our studies on perm-selective coating of alginate microbeads for islet transplantation.

Evaluating health-related quality of life in type 1 diabetes: a systematic literature review of utilities for adults with type 1 diabetes

Background and aims

Type 1 diabetes is a chronic condition associated with micro- and macrovascular complications that have a notable impact on health-related quality of life, the magnitude of which can be quantified via the use of utility values. The aim of this review was to conduct a systematic literature review to identify and compare published health state utility values for adults with type 1 diabetes both, with and without diabetes-related complications.

Methods

Literature searches of the PubMed, EMBASE, and Cochrane Library databases were performed to identify English language studies on adults with type 1 diabetes, published from 2000 onward, reporting utility values for patients with or without diabetes-related complications or assessing the impact of changes in HbA1c or body mass index on quality of life. For inclusion, studies were required to report utilities elicited using validated methods.

Results

A total of 20 studies were included in the final review that included utility values elicited using the EuroQuol five dimensions questionnaire (n=9), 15D questionnaire (n=2), Quality of Well-Being scale (n=4), time trade-off (n=3), and standard gamble (n=2) methods. For patients with no complications, reported utility values ranged from 0.90 to 0.98. Complications including stroke (reported disutility range, −0.105 to −0.291), neuropathy (range, −0.055 to −0.358), and blindness (range, −0.132 to −0.208) were associated with the largest decrements in utility values. The magnitude of utility values and utility decrements was influenced by the assessment method used.

Conclusion

Complications lead to impaired health-related quality of life in patients with type 1 diabetes, the magnitude of which is influenced by the method used to determine utilities. There is currently a lack of utility data for certain complications of type 1 diabetes, meaning that many economic evaluations have relied on a combination of type 1 and type 2 diabetes utilities, despite differences between the conditions and populations, or type 1 diabetes-specific utilities derived from different instruments.