Development of New Macroencapsulating Planar Devices to Inhibit Allorejection of Islet Transformed Cells

To observe the effect of inhibiting long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) on diabetic neurodegeneration. Thirty-six 8-week-old C57BL/6 mice were randomly divided into normal control, diabetic control, diabetic scrambled small interfering RNAs (siRNAs) and diabetic MALAT1-siRNA groups. After diabetic induction with streptozocin intraperitoneally-injection, the diabetic MALAT1-siRNA group was intravitreally injected with 1 µL 20 µmol/L MALAT1 siRNA, and the diabetic scrambled siRNA group was injected with the same amount of scrambled siRNA. Electroretinography was performed to examine photoreceptor functions 16wk after diabetes induction. MALAT1 expression was detected via real time polymerase chain reaction. Cone morphological changes were examined using immunofluorescence. Rod morphological changes were examined by determining outer nuclear layer (ONL) thickness. The upregulation of retinal MALAT1 expression was detected in the diabetic control mice, while MALAT1 expression in the diabetic MALAT1-siRNA mice was decreased by 91.48% compared to diabetic control mice. The diabetic MALAT1-siRNA and diabetic control mice showed lower a-wave and b-wave amplitudes than did the normal control mice in scotopic and photopic electroretinogram, while the diabetic MALAT1-siRNA mice showed higher amplitudes than diabetic control mice. Morphological examination revealed that ONL thickness in the diabetic MALAT1-siRNA and diabetic control mice was lower than normal control mice. However, ONL thickness was greater in the diabetic MALAT1-siRNA mice than diabetic control mice. Moreover, the diabetic control mice performed a sparser cone cell arrangement and shorter outer segment morphology than diabetic MALAT1-siRNA mice. Inhibiting retinal MALAT1 results in mitigative effects on the retinal photoreceptors, thus alleviating diabetic neurodegeneration.

Transplanting islets into the subcutaneous (SC) space rather than the portal vein is advantageous because this site is easier and safer to use. However, transplantation of islets directly or within planar devices has been unsuccessful in humans, mainly because of the low oxygen torr in the SC space. Since human islets are very different from mouse islets, the use of human islets in animal experiments to study SC islet transplantation may help to alleviate the roadblocks of this approach in humans. This is the first report that explores methods for SC transplantation of human islets in mice. <em>In vitro</em> studies showed that Matrigel and Geltrex serve well as islet cell matrices, whereas none of the Cytodex formulations were useful. Doses of FGF2 as high as 10,000 ng/ml were not toxic to human islets <em>in vitro</em> and could be used <em>in vivo</em>. Human islets are more viable in macroencapsulation devices than on standard culture plates. <em>In vivo</em> studies demonstrated that transplanting human islets SC into diabetic nude mice does not lower blood glucose, and administering FGF2 at the site two weeks before transplantation results in only a minimal decrease in blood glucose. SC transplantation of islets within a silicone scaffold reduced blood glucose to below 150 mg/dl by day 14, effectively normalizing blood glucose in all diabetic nude mice, whereas control mice showed no decline. Mean blood glucose remained lower than in control mice from day 6 through the end of the experiment (p < 0.05). Preimplantation of the scaffold with FGF2 augments the early decline in blood glucose. Using a 0.4 µm pore immunoprotective PTFE macroencapsulating device, FGF administration was crucial for any lowering of blood glucose in transplanted mice. The maximally effective decline in blood glucose occurred when FGF2 was preimplanted within and outside the device. This results in 100% of transplanted FGF-treated mice achieving euglycemia, while no decline in blood glucose levels occurred in control animals. When islets were transplanted SC into a 10 µm macroencapsulation device suitable for local immunotherapy, blood glucose normalized quickly in all mice and remained euglycemic for more than 9 months, whereas no control mice developed euglycemia. The aforementioned approaches of utilizing scaffolds and devices are promising for successfully studying and developing SC transplantation of human islets.

Engineered Enteroendocrine Cells Secrete Insulin in Response to Glucose and Reverse Hyperglycemia in Diabetic Mice

Influence of membrane structure on fouling layer morphology during apple juice clarification

Loss of TM-Dependent PC-Activation Predisposes to Diabetic Nephropathy: Potential Role of Endothelial Apoptosis.

Hepatic transcriptome and proteome analyses provide new insights into the regulator mechanism of dietary avicularin in diabetic mice.

Separation of casein from whey proteins by dynamic filtration

In diabetes, endothelial nitric oxide synthase (eNOS) produces superoxide anion rather than nitric oxide, referred to as "eNOS uncoupling," which may contribute to endothelial dysfunction, albuminuria, and diabetic nephropathy. Reduced levels of endothelium-derived tetrahydrobiopterin (BH4), an essential cofactor for eNOS, promote eNOS uncoupling. Accelerated degradation of guanosine triphosphate cyclohydrolase I (GTPCH I), the rate-limiting enzyme in BH4 biosynthesis, also occurs in diabetes, suggesting that GTPCH I may have a role in diabetic microvascular disease. Here, we crossed endothelium-dominant GTPCH I transgenic mice with Ins2(+/Akita) diabetic mice and found that endothelial overexpression of GTPCH I led to higher levels of intrarenal BH4 and lower levels of urinary albumin and reactive oxygen species compared with diabetic control mice. Furthermore, GTPCH I overexpression attenuated the hyperpermeability of macromolecules observed in diabetic control mice. In addition, we treated Ins2(+/Akita) mice with metformin, which activates AMP-activated protein kinase (AMPK) and thereby slows the degradation of GTPCH I; despite blood glucose levels that were similar to untreated mice, those treated with metformin had significantly less albuminuria. Similarly, in vitro, treating human glomerular endothelial cells with AMPK activators attenuated glucose-induced reductions in phospho-AMPK, GTPCH I, and coupled eNOS. Taken together, these data suggest that maintenance of endothelial GTPCH I expression and the resulting improvement in BH4 biosynthesis ameliorate diabetic nephropathy.

Moisture diffusion measurement and evaluation for porous membranes used in enthalpy exchangers

Leea species are used traditionally to treat diabetes, cancer, rheumatism, and arthritis. This study assessed the antidiabetic potential of Leea rubra leaves (LRL). LRL was extracted with methanol, and its antidiabetic potential was evaluated through hypoglycemic screening in normoglycemic mice, oral glucose tolerance test (OGTT), and antihyperglycemic test in streptozotocin (STZ)-induced (45 mg/kg, 3 days) diabetic mice, using two doses of the LRL extract (40 and 80 mg/kg) and glibenclamide (5 mg/kg). For the hypoglycemic and OGTT studies, mice received a single oral dose of LRL extract or glibenclamide, with normal control group receiving vehicle only. For the antihyperglycemic studies, diabetic control mice received vehicle, while treatment groups received daily oral doses of LRL extract or glibenclamide for 15 consecutive days. At the end of treatment, blood glucose levels and body weights were measured. Acute toxicity study, conducted according to OECD guideline 425, showed that the extract is safe with ≥2 g/kg. The extract at dose of 80 mg/kg showed significant hypoglycemic activity (p<0.001) and oral glucose tolerance (p<0.0001) compared to normal control. In diabetic mice, both doses of the extract showed statistically significant (p<0.0001) antihyperglycemic activity at the 15th day of treatment in comparison with the diabetic control mice. The extract at 80 mg/kg showed significant (p<0.05) improvement in body weight. These findings confirm the antidiabetic potential of LRL, suggesting that it may serve as a promising candidate for developing novel antidiabetic therapies, and further research is needed to elucidate the underlying mechanisms of action.

The study aims to map plasma gelsolin (pGSN) levels in diabetic humans and mice models of type II diabetes and to evaluate the efficacy of gelsolin therapy in improvement of diabetes in mice. We report that pGSN values decrease by a factor of 0.45 to 0.5 in the blood of type II diabetic humans and mice models. Oral glucose tolerance test in mice models showed that subcutaneous administration of recombinant pGSN and its F-actin depolymerizing competent versions brought down blood sugar levels comparable to Sitagliptin, a drug used to manage hyperglycemic condition. Further, daily dose of pGSN or its truncated versions to diabetic mice for a week kept sugar levels close to normal values. Also, diabetic mice treated with Sitagliptin for 7 days, showed increase in their pGSN values with the decrease in blood glucose as compared to their levels at the start of treatment. Gelsolin helped in improving glycemic control in diabetic mice. We propose that gelsolin level monitoring and replacement of F-actin severing capable gelsolin(s) should be considered in diabetic care.

Camel whey protein improves oxidative stress and histopathological alterations in lymphoid organs through Bcl-XL/Bax expression in a streptozotocin-induced type 1 diabetic mouse model.

Vitamin D3 improves lipophagy-associated renal lipid metabolism and tissue damage in diabetic mice

Islet transplantation is a promising cell therapy for patients with diabetes, but it is currently limited by the reliance upon cadaveric donor tissue. We previously demonstrated that human embryonic stem cell (hESC)-derived pancreatic progenitor cells matured under the kidney capsule in a mouse model of diabetes into glucose-responsive insulin-secreting cells capable of reversing diabetes. However, the formation of cells resembling bone and cartilage was a major limitation of that study. Therefore, we developed an improved differentiation protocol that aimed to prevent the formation of off-target mesoderm tissue following transplantation. We also examined how variation within the complex host environment influenced the development of pancreatic progenitors in vivo. The hESCs were differentiated for 14 days into pancreatic progenitor cells and transplanted either under the kidney capsule or within Theracyte (TheraCyte, Laguna Hills, CA, USA) devices into diabetic mice. Our revised differentiation protocol successfully eliminated the formation of non-endodermal cell populations in 99% of transplanted mice and generated grafts containing >80% endocrine cells. Progenitor cells developed efficiently into pancreatic endocrine tissue within macroencapsulation devices, despite lacking direct contact with the host environment, and reversed diabetes within 3 months. The preparation of cell aggregates pre-transplant was critical for the formation of insulin-producing cells in vivo and endocrine cell development was accelerated within a diabetic host environment compared with healthy mice. Neither insulin nor exendin-4 therapy post-transplant affected the maturation of macroencapsulated cells. Efficient differentiation of hESC-derived pancreatic endocrine cells can occur in a macroencapsulation device, yielding glucose-responsive insulin-producing cells capable of reversing diabetes.

Tissue ischemia promotes vasculogenesis through chemokine-induced recruitment of bone marrow-derived endothelial progenitor cells (EPCs). Diabetes significantly impairs this process. Because hyperglycemia increases reactive oxygen species in a number of cell types, and because many of the defects responsible for impaired vasculogenesis involve HIF1-regulated genes, we hypothesized that HIF1 function is impaired in diabetes because of reactive oxygen species-induced modification of HIF1alpha by the glyoxalase 1 (GLO1) substrate methylglyoxal. Decreasing superoxide in diabetic mice by either transgenic expression of manganese superoxide dismutase or by administration of an superoxide dismutase mimetic corrected post-ischemic defects in neovascularization, oxygen delivery, and chemokine expression, and normalized tissue survival. In hypoxic fibroblasts cultured in high glucose, overexpression of GLO1 prevented reduced expression of both the EPC mobilizing chemokine stromal cell-derived factor-1 (SDF-1) and of vascular epidermal growth factor, which modulates growth and differentiation of recruited EPCs. In hypoxic EPCs cultured in high glucose, overexpression of GLO1 prevented reduced expression of both the SDF-1 receptor CXCR4, and endothelial nitric-oxide synthase, an enzyme essential for EPC mobilization. HIF1alpha modification by methylglyoxal reduced heterodimer formation and HIF1alpha binding to all relevant promoters. These results provide a basis for the rational design of new therapeutics to normalize impaired ischemia-induced vasculogenesis in patients with diabetes.