New stepwise cooling system for short-term porcine islet preservation

Adhesion Characteristics of Human Pancreatic Islets, Duct Epithelial Cells, and Acinar Cells to a Polymer Scaffold

We reported in 2018 that among several extracellular matrices, fibronectin, type I collagen, type IV collagen, laminin I, fibrinogen, and bovine serum albumin, fibronectin is particularly useful for adhesion of porcine pancreatic tissue. Subsequently, we developed a technology that enables the chemical coating of the constituent motifs of fibronectin onto cell culture dishes. In this experiment, we used islets (purity ≥ 90%), duct epithelial cells (purity ≥ 60%), and acinar cells (purity ≥ 99%) isolated from human pancreas according to the Edmonton protocol published in 2000 and achieved adhesion to the constituent motifs of fibronectin. A solution including cGMP Prodo Islet Media was used as the assay solution. In islets, adhesion was enhanced with the constitutive motifs of fibronectin compared with uncoated islets. In the functional evaluation of islets, insulin mRNA expression and insulin secretion were enhanced by the constitutive motif of fibronectin compared with non-coated islets. The stimulation index was comparable between non-coated islets and fibronectin motifs. In duct epithelial cells, adhesion was mildly promoted by the fibronectin component compared with non-coated component, while in acinar cells, adhesion was inhibited by the fibronectin component compared with the non-coated component. These data suggest that the constitutive motifs of fibronectin are useful for the adhesion of islets and duct epithelial cells.

The Fragility of Cryopreserved Insulin-producing Cells Differentiated from Adipose-tissue-derived Stem Cells

The aim of our study is to determine whether insulin-producing cells (IPCs) differentiated from adipose-tissue-derived stem cells (ADSCs) can be cryopreserved. Human ADSCs were differentiated into IPCs using our two-step protocol encompassing a three-dimensional culture and xenoantigen-free method. Thereafter, IPCs were frozen using three different methods. First, IPCs were immediately frozen at -80°C (-80°C group). Second, IPCs were initially placed into a Bicell freezing container before freezing at -80°C (BICELL group). Third, a vitrification method for oocytes and embryos was used (CRYOTOP group). Cell counting kit-8 (CCK-8) assay showed that cell viability was decreased in all groups after cryopreservation (P < 0.01). Corroboratively, the amount of adenosine triphosphate was markedly decreased after cryopreservation in all groups (P < 0.01). Immunofluorescence staining showed a reduced positive staining area for insulin in all cryopreservation groups. Furthermore, 4',6-diamidino-2-phenylindole and merged immunofluorescence images showed that cryopreserved cells appeared to be randomly reduced in the -80°C group and CRYOTOP group, while only the central region was visibly reduced in the BICELL group. Using immunohistochemical staining, IPCs after cryopreservation were shown to be positive for cleaved caspase-3 antibody in all groups. Finally, insulin secretion following glucose stimulation was significantly reduced in IPCs from all groups after cryopreservation (P < 0.01). In conclusion, IPCs may be too fragile for cryopreservation with accomplished methods and further investigations for a suitable preservation method are required.

Adipose Tissue From Type 1 Diabetes Mellitus Patients Can Be Used to Generate Insulin-Producing Cells

OBJECTIVES

We aimed to determine whether responsive insulin-producing cells (IPCs) could be generated from adipose-derived stem cells (ADSCs) isolated from patients with type 1 diabetes mellitus (T1DM).

METHODS

We isolated ADSCs from adipose tissue of 4 patients (one patient with T1DM and 3 nondiabetic patients), who underwent surgery and differentiated them into IPCs with using a 2-step xeno-antigen free, 3-dimensional culture method. Characteristics of isolated ADSCs, in vitro cell quality, programmed cell death ligand-1 (PDL-1) expression, and transplantation into streptozotocin induced diabetic nude mice were investigated.

RESULTS

Adipose-derived stem cells from T1DM patients and commercially obtained ADSCs showed the same surface markers; CD31CD34CD45CD90CD105CD146. Moreover, the generated IPCs at day 21 demonstrated appropriate autonomous insulin secretion (stimulation index, 3.5; standard deviation, 0.8). Nonfasting blood glucose concentrations of IPC-transplanted mice were normal at 30 days. The normalized rate of IPC-transplanted mice was significantly higher than that of the sham-operated group (P < 0.05). Insulin-producing cells generated from T1DM adipose tissue expressed high levels of PDL-1.

CONCLUSIONS

Insulin-producing cells obtained from adipose tissue of T1DM patients are capable of secreting insulin long-term and achieve normoglycemia after transplantation. Expression of PDL-1 suggests the potential for immune circumvention.

In vitro and in vivo effects of insulin-producing cells generated by xeno-antigen free 3D culture with RCP piece

To establish widespread cell therapy for type 1 diabetes mellitus, we aimed to develop an effective protocol for generating insulin-producing cells (IPCs) from adipose-derived stem cells (ADSCs). We established a 3D culture using a human recombinant peptide (RCP) petaloid μ-piece with xeno-antigen free reagents. Briefly, we employed our two-step protocol to differentiate ADSCs in 96-well dishes and cultured cells in xeno-antigen free reagents with 0.1 mg/mL RCP μ-piece for 7 days (step 1), followed by addition of histone deacetylase inhibitor for 14 days (step 2). Generated IPCs were strongly stained with dithizone, anti-insulin antibody at day 21, and microstructures resembling insulin secretory granules were detected by electron microscopy. Glucose stimulation index (maximum value, 4.9) and MAFA mRNA expression were significantly higher in 3D cultured cells compared with conventionally cultured cells (P < 0.01 and P < 0.05, respectively). The hyperglycaemic state of streptozotocin-induced diabetic nude mice converted to normoglycaemic state around 14 days after transplantation of 96 IPCs under kidney capsule or intra-mesentery. Histological evaluation revealed that insulin and C-peptide positive structures existed at day 120. Our established xeno-antigen free and RCP petaloid μ-piece 3D culture method for generating IPCs may be suitable for clinical application, due to the proven effectiveness in vitro and in vivo.

A New 2-Step Acceleration Protocol Using a Histone Deacetylase Inhibitor to Generate Insulin-Producing Cells From Adipose-Derived Mesenchymal Stem Cells

OBJECTIVES

We aimed to develop a simple protocol for deriving insulin-producing cells (IPCs) from adipose-derived mesenchymal stem cells (ADSCs). We established a 2-step creation method and an acceleration strategy with a histone deacetylase inhibitor that promoted a pro-endocrine pancreatic lineage.

METHODS

We seeded ADSCs in 96-well dishes and cultured in Dulbecco's modified Eagle's medium/F12 medium containing 1% fetal bovine serum, 1% B27 supplement, 1% N2 supplement, 50-ng/mL human activin A, and 10-nM exendin-4 for step 1 of differentiation (7 days). Then 10-mM nicotinamide and 50-ng/mL human hepatocyte growth factor, with or without 1 mM histone deacetylase inhibitor, were added for step 2 of differentiation (14 days). After the 2-step differentiation was complete, cell morphology, immunohistochemistry, messenger RNA expression, and function were investigated.

RESULTS

Our new differentiation protocol with the histone deacetylase inhibitor significantly accelerated IPC differentiation compared with the conventional protocol without the histone deacetylase inhibitor (median, 21.6 vs 38.8 days; P < 0.05). It also improved the islet morphology score (P < 0.05) and the glucose stimulation index (3.1).

CONCLUSIONS

By applying our new and easy 2-step protocol using a histone deacetylase inhibitor, ADSCs may be an effective cell source for differentiation of IPCs.

Pancreatic Islets: Methods for Isolation and Purification of Juvenile and Adult Pig Islets

The current situation of organ transplantation is mainly determined by the disbalance between the number of available organs and the number of patients on the waiting list. This obvious dilemma might be solved by the transplantation of porcine organs into human patients. The metabolic similarities which exist between both species made pancreatic islets of Langerhans to that donor tissue which will be most likely transplanted in human recipients. Nevertheless, the successful isolation of significant yields of viable porcine islets is extremely difficult and requires extensive experiences in the field. This review is focussing on the technical challenges, pitfalls and particularities that are associated with the isolation of islets from juvenile and adult pigs considering donor variables that can affect porcine islet isolation outcome.

Islet Culture/Preservation Before Islet Transplantation

Although islet culture prior to transplantation provides flexibility for the evaluation of isolated islets and the pretreatment of patients, it is well known that isolated islets deteriorate rapidly in culture. Human serum albumin (HSA) is used for medium supplementation instead of fetal bovine serum (FBS), which is typically used for islet culture research, to avoid the introduction of xenogeneic materials. However, FBS contains several factors that are beneficial to islet viability and which also neutralize the endogenous pancreatic enzymes or exogenous enzymes left over from the isolation process. Several groups have reported the comparison of cultures at 22°C and 37°C. Recent studies have demonstrated the superiority of 4°C preservation to 22°C and 37°C cultures. We herein review the current research on islet culture/preservation for clinical islet transplantation.

Impact of a new refrigerator on the preservation of hepatic grafts

AIM

  Current medical transplantation methods focus on solutions for major problems such as the shortage of donors. To overcome these issues, expanding organ preservation time has become a major concern. A new refrigerating chamber has been recently developed, which can cool the inside of a material to the required temperature by frequently sensing the temperature of both inside and surface of the materials. The purpose of this study is to evaluate the usefulness of a new refrigerating system in hepatic preservation.

METHODS

  The liver grafts were harvested from rats and divided into two groups. Group A consisted of grafts preserved in chilled University of Wisconsin solution (UW) solution (on ice) for 24, 72 and 168 h. Group B consisted of grafts preserved in the UW solution in a new refrigerator at 4°C.

RESULTS

  In group B, aspartate aminotransferase released into effluent after cold storage for 72 h showed a marked decrease compared to group A (P < 0.05). The levels of ammonia and lactate decreased significantly in group B (P < 0.05). In group B, the levels of adenosine triphosphate were significantly preserved after cold storage for 24 h and 72 h compared to group A (P < 0.05). Immunohistochemistry showed positive cells for heme oxygenase-1 were significantly increased in group B after cold storage.

CONCLUSION

  This new refrigerator can improve preservation injury of hepatic grafts and may provide an innovative technique for liver transplantation.

Human adipose-derived stem cells: potential clinical applications in surgery

Regenerative medicine is emerging as a rapidly evolving field of research and therapeutics. Stem cells hold great promise for future translational research and clinical applications in many fields. Much research has focused on mesenchymal stem cells isolated from bone marrow in vitro and in vivo; however, bone marrow procurement causes considerable discomfort to the patient and yields a relatively small number of harvested cells. By contrast, adipose tissue represents an abundant and easily accessible source of adult stem cells, termed adipose-derived stem cells (ADSCs), with the ability to equally differentiate along multiple lineage pathways. These stem cells have angiogenic properties, possibly because of their secretion of cytokines. They may also play a role in healing acute and chronic tissue damage. Subsequently, they have a wide range of potential clinical implications. This article reviews the potential preclinical and clinical applications of mesenchymal stem cells, especially ADSCs, in surgery.

Impact of a new refrigerator for the preservation of whole blood

BACKGROUND

A new refrigerating system has been recently developed, which can cool the inside of a material to the required temperature by frequently sensing the temperature of both the inside and the surface of the materials. The purpose of this study was to evaluate the usefulness of this new system in whole blood preservation.

MATERIALS AND METHODS

Study 1 (human blood): Whole blood samples from healthy volunteers were anticoagulated with CPDA. The samples were divided into two groups. Group A, whole blood preserved in ordinary refrigerator and Group B, whole blood preserved in new refrigerator (4°C, 15 wk). After preservation, ammonia, lactate, pH. and ATP levels were analyzed. Study 2 (rat experiment): Whole blood samples from male Wistar rats, stored in ordinary refrigerator (Group C) or new refrigerator (Group D). Whole blood was transfused after 8-wk storage and survival was compared.

RESULTS

Study 1: The ammonia concentrations in Group B were significantly lower than those in Group A at 7 and 9 wk after preservation (P < 0.05). The lactate levels in Group B were significantly lower than those in Group A at 9 wk after preservation (P < 005). The pH levels in Group B were higher than those in Group A at 5 to 13 wk after preservation (P < 0.05). The ATP levels in Group B were higher than those in Group A at 5 to 13 wk after preservation. Study 2: In rat studies using blood transfusion in acute hemorrhagic shock model, survival rate in Group C was significantly higher than those in Group D (P < 0.05).

CONCLUSIONS

Our new refrigerator is useful in preserving whole blood with good condition during preservation.