Butyrate and Class I Histone Deacetylase Inhibitors Promote Differentiation of Neonatal Porcine Islet Cells into Beta Cells

Neonatal porcine islets-like clusters (NPICCs) are a promising source for cell therapy of type 1 diabetes. Freshly isolated NPICCs are composed of progenitor cells and endocrine cells, which undergo a maturation process lasting several weeks until the normal beta cell function has developed. Here, we investigated the effects of short-chain fatty acids on the maturation of islet cells isolated from two to three day-old piglets. NPICCs were cultivated with acetate, butyrate and propionate (0–2000 µM) for one to eight days. Incubation with butyrate resulted in a significant upregulation of insulin gene expression and an increased beta cell number, whereas acetate or propionate had only marginal effects. Treatment with specific inhibitors of G-protein-coupled receptor GPR41 (β-hydroxybutyrate) and/or GPR43 (GPLG0974) did not abolish butyrate induced insulin expression. However, incubation of NPICCs with class I histone deacetylase inhibitors (HDACi) mocetinostat and MS275, but not selective class II HDACi (TMP269, MC1568) mimicked the butyrate effect on beta cell differentiation. Our study revealed that butyrate treatment has the capacity to increase the number of beta cells, which may be predominantly mediated through its HDAC inhibitory activity. Butyrate and specific class I HDAC inhibitors may represent beneficial supplements to promote differentiation of neonatal porcine islet cells towards beta cells for cell replacement therapies.

Carbohydrate antigen microarray analysis of serum IgG and IgM antibodies before and after adult porcine islet xenotransplantation in cynomolgus macaques

Understanding the anti-carbohydrate antibody response toward epitopes expressed on porcine cells, tissues, and organs is critical to advancing xenotransplantation toward clinical application. In this study, we determined IgM and IgG antibody specificities and relative concentrations in five cynomolgus monkeys at baseline and at intervals following intraportal xenotransplantation of adult porcine islets. This study utilized a carbohydrate antigen microarray that comprised more than 400 glycoconjugates, including historically reported α-Gal and non-α-Gal carbohydrate antigens with various modifications. The elicited anti-carbohydrate antibody responses were predominantly IgM compared to IgG in 4 out of 5 monkeys. Patterns of elicited antibody responses greater than 1.5 difference (log2 base units; 2.8-fold on a linear scale) from pre-serum to post-serum sampling specific for carbohydrate antigens were heterogeneous and recipient-specific. Increases in the elicited antibody response to α-Gal, Sda, GM2 antigens, or Lexis X antigen were found in individual monkeys. The novel carbohydrate structures Galβ1-4GlcNAcβ1-3Galβ1 and N-linked glycans with Manα1-6(GlcNAcβ1-2Manα1–3)Manβ1-4GlcNAcβ structure were common targets of elicited IgM antibodies. These results provide important insights into the carbohydrate epitopes that elicit antibodies following pig-to-monkey islet xenotransplantation and reveal possible targets for gene editing.

What does it take to consent to islet cell xenotransplantation?: Insights from an interview study with type 1 diabetes patients and review of the literature

Background The transplantation of porcine islet cells provides a new potential therapy to treat patients with type 1 diabetes mellitus (T1DM). Compared to other biomedical technologies, xenotransplantation stands out in terms of its involvement of animals as graft sources, as well as the possible transmission of infectious diseases. As these aspects are especially relevant for potential xenotransplantation recipients, it is important to assess their opinion regarding this technology, in particular in terms of the requirements that should be met in the informed consent process for xenotransplantation. Methods We conducted qualitative interviews with seven T1DM patients to assess their information needs prior to xenotransplantation. Before the interview, the participants received a model informed consent form for a clinical trial with porcine islet cells transplantation. The interviews were transcribed and analysed using qualitative content analysis. Results In the interviews, we identified several requirements that are crucial for patients with T1DM in order to consider xenotransplantation as a potential treatment option: therapy-related requirements, professional care and supervision, successful behaviour and attitude management, improving quality of life, and managing control/self-determination challenges. Regarding the informed consent form, several of the participants’ questions remained open and should be addressed in more detail. The interviewees stressed the importance of personal consultations. Conclusions To become a sustainable therapeutic option, patients especially expected an improved diabetes control and a reduction of diabetes-related burdens. Health-related aspects prove to be pivotal for diabetic patients when considering porcine islet cell transplantation. The use of pigs as source for organ retrievals was not considered as problematic.

Optimization of Nano-encapsulation on Neonatal Porcine Islet-like Cell Clusters Using Polymersomes

Researches proving methods for nano-encapsulation of neonatal porcine islet-like cell clusters (NPCCs) using polymersomes (PSomes) formed using polymers of polyethylene glycol-block-poly lactide. Herein, our studies present efficient nano-encapsulation procedure with minimal damage and loss of NPCCs.We used N-hydroxysuccinimide (NHS) on the N-terminal of PSomes to induce binding of amine groups in the extracellular matrix surrounding NPCCs. F-10 culture medium with bovine serum albumin was used in the nano-encapsulation procedure to minimize damage and loss of NPCCs. Finally, we induced cross-linking between bifunctional PSomes (NHS-/NH2-PSomes). F-10 culture medium containing 0.25% BSA with pH of 7.3 minimized the damage and loss of NPCCs after nano-encapsulation as compared with using basic HBSS buffer (pH 8.0). Also, we induced the efficient nano-encapsulation through conjugation of PSomes using bifunctional PSomes (NHS-/NH2-PSomes).