Reversal of Hypoglycemia Unawareness with a Single-donor, Marginal Dose Allogeneic Islet Transplantation in Korea: A Case Report

Pancreatic islet transplantation is a physiologically advantageous and minimally invasive procedure for the treatment of type 1 diabetes mellitus. Here, we describe the first reported case of successful allogeneic islet transplantation alone, using single-donor, marginal-dose islets in a Korean patient. A 59-yr-old patient with type 1 diabetes mellitus, who suffered from recurrent severe hypoglycemia, received 4,163 islet equivalents/kg from a single brain-death donor. Isolated islets were infused intraportally without any complications. The immunosuppressive regimen was based on the Edmonton protocol, but the maintenance dosage was reduced because of mucositis and leukopenia. Although insulin independence was not achieved, the patient showed stabilized blood glucose concentration, reduced insulin dosage and reversal of hypoglycemic unawareness, even with marginal dose of islets and reduced immunosuppressant. Islet transplantation may successfully improve endogenous insulin production and glycemic stability in subjects with type 1 diabetes mellitus.

25-Hydroxyvitamin D is closely related with the function of the pancreatic islet beta cells

This study is to investigate the relationship between 25-Hydroxyvitamin D [25-OH-D] and pancreatic islet beta cell function under different glucose tolerance statuses in China. Totally, 180 patients with type 2 diabetes mellitus [DM group], 178 patients with impaired fasting glucose/impaired glucose tolerance [IFG/IGT group], and 160 normal control subjects [NGT group] were included to measure their body parameters and biochemical parameters. In oral glucose tolerance test, fasting serum 25-OH-D was assessed by the enzyme-linked immunosorbent assay [ELISA]. Homeostasis model assessment for insulin resistance [Homa-IR], insulin acuity index [IAI], beta -cell function index [Homa-BCF] as well as secretion index [IS] were determined. The levels of 25-OH-D, IAI and Homa-BCF in the DM group and IFG/IGT group were significantly lower than that in NGT group [P < 0.05]. Homa-IR in DM group and IFG/IGT group was significantly higher than that in the NGT group [P < 0.05]. Pearson correlation analysis and partial correlation analysis showed that 25-OH-D was positively correlated with fasting insulin [FINS] and Homa-BCF [P < 0.05]. Multiple stepwise regression analysis showed that 25-OH-D was one of the influential factors of pancreatic islet beta cell function in patients with type 2 diabetes mellitus. Our results suggest that 25-OH-D is closely related with the function of the pancreatic islet beta cells and is one of the influential factors of pancreatic islet beta cell function

Exendin-4 effects on islet volume and number in mouse pancreas

The aim of this study was to evaluate Exendin-4 (EX-4) effects on islet volume and number in the mouse pancreas. Thirty-two healthy adult male NMRI mice were randomly divided into control and experimental groups. EX-4 was injected intraperitoneally (i. p.) at doses of 0.25 (E1 group), 0.5 (E2 group), and 1 µg/kg (E3 group), twice a day for 7 consecutive days. One day after the final injection, the mice were sacrificed, and the pancreas from each animal dissected out, weighed, and fixed in 10% formalin for measurement of pancreas and islet volume, and determination of islet number by stereological assessments. There was a significant increase in the weight of pancreases in the E3 group. Islet and pancreas volumes in E1 and E2 groups were unchanged compared to the control group. The E3 group showed a significant increase in islet and pancreas volume (P < 0.05). There were no significant changes in the total number of islets in all three experimental groups. The results revealed that EX-4 increased pancreas and islet volume in non-diabetic mice. The increased total islet mass is probably caused by islet hypertrophy without the formation of additional islets.

O objetivo deste estudo foi avaliar os efeitos do Exendin-4 (EX-4) sobre o volume e número de ilhotas no pâncreas. Trinta e dois camundongos NMRI machos saudáveis e adultos foram divididos ao acaso em grupos controle e grupos experimentais. EX-4 foi injetado intraperitonealmente (i. p.) nas doses de 0,25 (grupo E1), 0,5 (grupo E2) e 1 (grupo E3), duas vezes por dia durante 7 dias consecutivos. Um dia após a injeção final, os camundongos foram sacrificados e o pâncreas de cada animal foi dissecado, pesado e fixado em solução de formaldeído 10% para avaliação do volume do pâncreas e ilhotas e do número de ilhotas por métodos estereológicos. Observou-se aumento significativo no peso de pâncreas no grupo E3. O volume do pâncreas assim como das ilhotas não apresentou alterações nos grupos E1 e E2, quando comparados ao grupo controle No grupo E3 houve aumento significativo no volume do pâncreas e das ilhotas (P<0,05). Não se observaram alterações significativas no número de ilhotas nos três grupos experimentais. Os resultados revelaram que o EX-4 provoca aumento no volume do pâncreas, bem como no volume das ilhotas em camundongos não-diabéticos. O aumento no volume total de ilhotas deve-se, provavelmente, a hipertrofia das ilhotas sem a formação de ilhotas adicionais.

[Inhibitory effect of GABA on glucose- stimulated insulin secretion from isolated islets of langerhans in rat]

Gamma-amino butyric acid [GABA], an amino acid, present in some inhibitory neurons of the central nervous system, is also found in relatively high levels in the islets of Langerhans. Results of different studies concerning the effect of GABA on insulin secretion are controversial. The aim of this study was to determine the role of GABA and GABAB receptors on glucose-stimulated insulin secretion in isolated islets of rats. The collagenase digestion technique was used to isolate the islets from pancreata of 45 male Wistar rats [200-250g]. Insulin secretion was assessed in eight islets in each cup exposed to different concentrations of glucose [8.3 and 16.7 mM] in the presence or absence of GABA [25, 50, 100 micro M], baclofen [10, 20, 50 micro M] [GABAB agonist] and saclofen [50,100 micro M] [GABAB antagonist]. Insulin concentration was measured by the ELISA method. Insulin release was reported as mean +/- SEM micro U/isIet/50 min and p values of <0.05 were considered significant. GABA inhibited glucose [8.3 and 16.7 mM]-induced insulin secretion in isolated islets [P<0.05]. Different concentrations of baclofen had no significant effect on glucose-induced insulin secretion; however glucose [16.7 mM] stimulated insulin secretion in the presence of 100 micro M saclofen [91 +/- 8.8 micro U/islet/60 min] was significantly [p<0.05] higher compared to insulin secretion stimulated by 16.7 mM glucose alone [67.7 +/- 2.58 micro U/islet/60 min]. These findings indicate that GABA has an inhibitory effect on glucose-induced insulin secretion; and therefore it may play a regulatory role in insulin secretion. This effect needs to be taken in to account in the pathophysiology of diabetes

Secondary prevention of type 1 diabetes mellitus: stopping immune destruction and promoting ß-cell regeneration

Type 1 diabetes mellitus results from a cell-mediated autoimmune attack against pancreatic ß-cells. Traditional treatments involve numerous daily insulin dosages/injections and rigorous glucose control. Many efforts toward the identification of ß-cell precursors have been made not only with the aim of understanding the physiology of islet regeneration, but also as an alternative way to produce ß-cells to be used in protocols of islet transplantation. In this review, we summarize the most recent studies related to precursor cells implicated in the regeneration process. These include embryonic stem cells, pancreas-derived multipotent precursors, pancreatic ductal cells, hematopoietic stem cells, mesenchymal stem cells, hepatic oval cells, and mature ß-cells. There is controversial evidence of the potential of these cell sources to regenerate ß-cell mass in diabetic patients. However, clinical trials using embryonic stem cells, umbilical cord blood or adult bone marrow stem cells are under way. The results of various immunosuppressive regimens aiming at blocking autoimmunity against pancreatic ß-cells and promoting ß-cell preservation are also analyzed. Most of these regimens provide transient and partial effect on insulin requirements, but new regimens are beginning to be tested. Our own clinical trial combines a high dose immunosuppression with mobilized peripheral blood hematopoietic stem cell transplantation in early-onset type 1 diabetes mellitus.

Histomorphological and quantitative immunohistochemical changes in the rat pancreas during aging

Although the endocrine pancreas is the purpose of several deep investigations, morphological data referred to the effect of aging on the gland are not homogeneous. The purpose of the current work was to analyze the changes occurring in the pancreas of aged rats, with especial reference to the islet cell populations. Six young (Y), old (O) and senescent (S) male Sprague-Dawley rats were used. The pancreas tails were processed for light microscopy and studied by means of routine stains as well as by immunohistochemical identification of insulin-, glucagon-, somatostatin-, and pancreatic polypeptide- secreting cells (Dako Envision System, DAB as chromogen). A progressive pancreatic histoarchitecture distortion was found among the aged animals. Even when the alterations were not uniformly observed, they appeared more evident and severe in the S group. The S rats showed significantly increased volume density and cell density of the B cell population, as well as larger number of islet profiles, when compared to O rats. A significant progressive increment of adipose tissue was also evident in aged animals. No abnormal changes were detected in the non.B cell populations of the different groups.

Microencapsulation and tissue engineering as an alternative treatment of diabetes

In the 70's, pancreatic islet transplantation arose as an attractive alternative to restore normoglycemia; however, the scarcity of donors and difficulties with allotransplants, even under immunosuppressive treatment, greatly hampered the use of this alternative. Several materials and devices have been developed to circumvent the problem of islet rejection by the recipient, but, so far, none has proved to be totally effective. A major barrier to transpose is the highly organized islet architecture and its physical and chemical setting in the pancreatic parenchyma. In order to tackle this problem, we assembled a multidisciplinary team that has been working towards setting up the Human Pancreatic Islets Unit at the Chemistry Institute of the University of São Paulo, to collect and process pancreas from human donors, upon consent, in order to produce purified, viable and functional islets to be used in transplants. Collaboration with the private enterprise has allowed access to the latest developed biomaterials for islet encapsulation and immunoisolation. Reasoning that the natural islet microenvironment should be mimicked for optimum viability and function, we set out to isolate extracellular matrix components from human pancreas, not only for analytical purposes, but also to be used as supplementary components of encapsulating materials. A protocol was designed to routinely culture different pancreatic tissues (islets, parenchyma and ducts) in the presence of several pancreatic extracellular matrix components and peptide growth factors to enrich the beta cell population in vitro before transplantation into patients. In addition to representing a therapeutic promise, this initiative is an example of productive partnership between the medical and scientific sectors of the university and private enterprises.

Influence of the pineal gland on the physiology, morphometry and morphology of pancreatic islets in rats

To investigate the influence of the pineal gland through melatonin secretion on the physiological and morphological parameters of pancreatic islets, we studied the plasma biochemistry and morphological and morphometric characteristics of the endocrine pancreas of male Wistar rats. The animals were distributed into five groups of ten rats each: NC - normal control group; NS - sham-operated group; Px (25) - pinealectomised group, studied 15-25 days after surgery; Px (70) - pinealectomised group, studied 60-70 days after surgery; ALX - alloxan monohydrate-treated group. Data are analyzed statistically by ANOVA and by the Kruskal-Wallis test. Although there was no significant difference in plasma glucose or insulin levels between the Px (25), Px (70) and NC groups, Px (25) animals showed a tendency to increased glucose and reduced insulin levels. The ALX group showed a clear elevation of plasma glucose and a reduction of plasma insulin compared to the other groups. Morphometric analysis showed a larger pancreatic islet area and a lower pancreatic islet density in the pancreas of Px (70) animals and an increase in degenerative pathological processes in the pancreatic islets of the Px (25) and ALX groups. The present results suggest that melatonin, in addition to acting on tissue sensitivity to insulin (as reported in other studies), affects the secretory action of beta cells, as demonstrated by the morphological and morphometric changes observed in pinealectomised animals

Dynamical complexity and temporal plasticity in pancreatic beta-cells.

We discuss some of the biological and mathematical issues involved in understanding and modelling the bursting electrical activity in pancreatic beta-cells. These issues include single-cell versus islet behaviour, parameter heterogeneity, channel noise, the effects of hormones, neurotransmitters, and ions, and multiple slow biophysical processes. Some of the key experimental and modelling studies are described, and some of the major open questions are discussed.

The C-peptide response to a standard mixed meal in a group of Brazilian type 1 diabetic patients

In order to analyze the different parameters used in the interpretation of C-peptide response in a functional test, we compared a group of 26 type 1 diabetics aged 21.1 + 8.2 years, with a diabetes duration of 7.9 + 6.7 months, with a group of 24 non-diabetic subjects aged 25.0 + 4.4 years. A standard mixed meal of 317 kcal was used as a stimulus. Blood sampling for C-peptide determinations was performed at regular intervals. Although all the studied C-peptide variables were significantly lower in the diabetic group (P<0.0001), some overlapping of parameters was observed between the two groups. The highest degree of overlapping was found for basal value (BV) (30.8 percent) and percent increase (42.31 percent), and the lowest for incremental area, absolute increase, peak value (PV) (3.8 percent), and total area (7.7 percent) (X2 = 31.6, P<0.0001). We did not observe a definite pattern in the time of maximum response among the 21 diabetics who showed an increase in C-peptide levels after the stimulus. In this group, however, there was a highly significant number of late responses (120 min) (X2 = 5.7, P<0.002). Although BV showed a significant correlation with PV (rs = 0.95, P<0.0001), the basal levels of C-peptide did not differentiate the groups with and without response to the stimulus. We conclude that the diabetic group studied showed delayed and reduced C-peptide responses, and that the functional test can be an important tool for the evaluation of residual beta cell function.

Intravenous glucose tolerance test in Macaca radiata radiata.

A reliable method for performing sensitive intravenous glucose tolerance tests in monkeys has been standardized. This helps in assessment of beta cell function. A normal curve for glucose disposal is constructed. A high variability in insulin levels is also documented.

Pancreatic beta cell function in normoglycaemic offspring of diabetic parents.

The aim of the study was to look for any time-realted fluctuation in the pancreatic beta cell function in normal offspring of diabetic parents, over a period of three years. Serum insulin (IRI) and C-peptide (CP) responses to oral glucose were reevaluated three years after the initial study in 25 normoglycaemic offspring of conjugal Type 2 diabetic parents. The mean area under the curve of IRI (AUC IRI) response was higher than normal control value in the offspring at both time points (P < 0.01) and the two values did not differ much. The 2 hr IRI was also significantly higher (P < 0.05) than the control value. CP responses at both time points in the offspring did not differ from the mean control value. Wide fluctuations in the individual IRI were noted on follow-up despite similar plasma glucose response. Follow-up IRI was higher in 6, lower in 5 (+/- 25% of the initial) and remained unaltered in the other 4 offspring. The corresponding CP showed increased values in 3, decreased values in 5 and no change in 7 offspring. The fluctuations were nonuniform in nature among the individuals studied. Disparity between the IRI and CP responses were present in 5 offspring during the follow-up. This study thus shows that wide fluctuations in insulin responses occur even in the normoglycaemic offspring of diabetic parents.

Respuesta Metabólica al trauma en el Páncreas Endocrino

Objetivo: Revisar el tema de la respuesta endocrinometabólica del páncreas ante un trauma. Fuente de datos: Trauma experimental de páncreas, trasplante de páncreas y de islotes y manejo de pacientes con adenomas insulares de células beta de páncreas. Síntesis de lo hallado: las células beta pancreáticas son heterogéneas, aún en su capacidad de regeneración. Aceptando los conceptos de regeneración y glucotoxicidad pancreática, se requiere una pérdida del 90 por ciento de la masa de células beta para inducir un estado diabético. Pérdidas menores causan alteración en la tolerancia a los carbohidratos, sólo si hay exposición a cargas prolongadas de glucosa. El número de células beta por páncreas probablemente varie con la especie que se estudie y con su estado de desarrollo, en humanos adultos se ha calculado en 600.000 islotes. La capacidad de respuesta secretoria de las células beta o el efecto de ella en el metabolismo de los carbohidratos es mejor evaluado por medio de la prueba con arginina en presencia de hiperglicemia. Sujetos sanos que han donado parcialmente su páncreas, tienen al año un deterioro en la secreción de insulina y en la tolerancia a la glucosa. Los trasplantes de páncreas, cursan con un hiperinsulinismo periférico y con una adecuada tolerancia a los carbphidratos. Se ha demostrado que la función de las células beta se mantienen cuando se trasplantan más de 200.000 islotes. Conclusiones: La información sobre el tema es escasa, es necesario establecer un protocolo de manejo temprano y seguimiento de los pacientes con trauma pancreático

Effects of protein-calorie malnutrition on endocrine pancreatic function in young preganant rats

Oral glucose tolerance test (GTT), insulin secretion after Oral glucose load and the insulin to glucose ratio (I/G) during GTT were measusred in Young (45-50 days old) pregnant and non-pregnant rats fed a normal (25% or low (6%) protein diet during pregnancy or for a 22-day period. Fasting blood glucose was lower in protein-deficient rats and basal insulin was higher in pregnant control rats than in non pregnant controls. Protein-deficient rats were intolerant to the Oral glucose load. The I/G ratio during GTT was higher in control pregnant rats than in other rats. These results show that young malnourished pregnant rats are glucose intolerant and do not show pregnancy hyperinsulinemia probably as a result of decreased pancreatic capacity to release insulin in response to stimulation

Inlet cell transplantation: important factors contributing to optimal pancreatic function

This study investigates four factors which are of utmost importance in contributing to optimal function of pancreatic tissue fragment allo transplants. Those being: viability of donor tissue, optimal weight of pancreatic tissue fragments, method of allograft preparation, and site of implantation. Seven groups of unrelated mongrel dogs underwent total pancreatectomy before being randomly assigned to one of the follo wing experimental groups. Group I (n = 10) anmimales were transplanted with >0.75 g/kg of viable, pancreatic tissue fragments, whereas those in Group II (n = 6) received <0.75 g/kg of nonviable pancreatic pieces. In both groups, the donor pancreases were processed without collagenase, before being injected into the renal subcapsular space. Mean survical among Group I animals was 43 ñ 17 days (M ñ SD), while dogs in Group II survived a mean of 2.6 ñ 0.9 days (M ñ SD). Dogs in Group III (n = 5) were injected in the supracapsular peritoneum with >0.75 g/kg of viable, collagenase-frww pancreatic tissue fragments, and mean survical was noted to be 3.1 ñ 1.2 days (M ñ SD). Recipients in Group IV (n = 5) received >0.75 g/kg of nonviable pancreatic tissue pieces prepared without collagenase in the renal subcapasular space, resulting in a mean survical of 2.8 ñ 0.9 days (M ñ SD). Group V (n = 6) animals survived a mean of 20 ñ 18 days (M ñ SD) when transplanted with >0.75 g/kg of viable pancreatic tissue fragments prepared with collagenase, in the renal subcapsular space. Animals in Group VI (n = 6) were injected intrasplenically with <0.75 g/kg of nonviable pancreatic pieces prepared without collagenase, and survived a mean of 4.2 ñ 1.2 days (M ñ SD). Viable, intrasplenic allografts of >0.75 g/kg were prepared with collagenase and administered to Group VII (n = 6) animals, who survived a mean of 7.7 ñ 4.6 days (M ñ SD). Animals in groups I-VII were given 2.5 mg/kg/day of azathioprine post-transplant, until death...