Autoimmunity and diabetes

Medicinal Plants Galega officinalis L. and Yacon Leaves as Potential Sources of Antidiabetic Drugs

Hypoglycemic and antioxidant properties of extracts of medicinal plants Galega officinalis L. (aboveground part) and yacon (Smallanthus sonchifolius Poepp. & Endl.) (leaves) as potential sources of biologically active substances with antidiabetic action have been studied. The pronounced hypoglycemic effect of Galega officinalis extract, devoid of alkaloids, at a dose of 600 mg/kg in experimental diabetes mellitus (DM) has been proven. The established effect is evidenced by a decrease in the concentration of glucose and glycosylated hemoglobin in the blood, increase glucose tolerance of cells, increase C-peptide and insulin content in the plasma of rats' blood. The effective hypoglycemic effect of the extract in the studied pathology was confirmed by histological examination of the pancreas. The cytoprotective effect of the studied extract on pancreatic cells at a dose of 1200 mg/kg was experimentally confirmed. In the standard cut area, an increase was found in the number of Langerhans islets, their average area, diameter, volume, and a number of β-cells relative to these indicators in animals with diabetes. Comparative screening of the antioxidant properties of 30, 50, 70, and 96% water-ethanol extracts of yacon indicates the highest potential of 50% water-ethanol extract to block free radicals in in vitro model experiments. The non-alkaloid fraction of Galega officinalis extract showed moderate antioxidant activity and was inferior to yacon extract in its ability to neutralize reactive oxygen species (ROS) and bind metal ions of variable valence. The level of antioxidant potential of the studied extracts is due to differences in the quantitative content of compounds of phenolic nature in their compositions. The obtained data on the biological effects of Galega officinalis extract on the structural and functional state of β-cells of the pancreas and antioxidant properties of Galega officinalis and yacon extracts substantiate the prospects of using these plants to create antidiabetic medicines and functional foods based on them.

Beneficial effects of physical exercise for β-cell maintenance in a type 1 diabetes mellitus animal model

NEW FINDINGS

What is the central question of this study? Type 1 diabetes mellitus (T1D) leads to hyperglycaemia owing to pancreatic β-cell destruction by the immune system. Physical exercise has been shown to have potentially beneficial protective roles against cytokine-induced pancreatic β-cell death, but its benefits are yet to be proved and should be understood better, especially in the islet environment. What is the main finding and its importance? Physical exercise protects against β-cell loss in a well-described animal model for T1D, induced by multiple low doses of streptozotocin. This seems to be related to reduced cytokine-induced β-cell death and increased islet cell proliferation. Contributions of islet neogenesis and/or transdifferentiation of pancreatic non-β-cells into β-cells cannot be excluded.

ABSTRACT

Physical exercise has beneficial effects on pancreatic β-cell function and survival in a pro-inflammatory environment. Although these effects have been linked to decreased islet inflammation and modulation of pro-apoptotic pathways, little is known about the islet microenvironment. Our aim was to evaluate the effects of physical exercise in islet histomorphology in a mouse model of type 1 diabetes mellitus induced by multiple low doses of streptozotocin. As expected, induction of type 1 diabetes mellitus led to β-cell loss and, consequently, decreased islet area. Interestingly, although the decrease in islet area was not prevented by physical exercise, this was not the case for the decrease in β-cell mass. This was probably related to induction of β-cell regeneration, because we observed increased proliferation and regeneration markers, such as Ki67 and Pcna, in islets of trained mice. These were found in the central and peripheral regions of the islets. An increase in the percentage of α- and δ-cells in these conditions, combined with an increase in proliferation and Pax4 labelling in peripheral regions, suggest that β-cell regeneration might also occur by transdifferentiation. This agrees with the presence of cells double stained for insulin and glucagon only in islets of diabetic trained mice. In addition, this group had more extra-islet insulin-positive cells and islets associated with ducts than diabetic mice. Physical exercise also decreased nuclear factor-κB activation in islet cells of diabetic trained compared with diabetic untrained mice, indicating a decrease in pro-inflammatory cytokine-induced β-cell death. Taken together, these findings indicate that preservation of β-cell mass induced by physical exercise involves an increase in β-cell replication and decrease in β-cell death, together with islet neogenesis and islet cell transdifferentiation.

Risk for Coexistent Autoimmune Diseases in Familial and Sporadic Type 1 Diabetes is Related to Age at Diabetes Onset

OBJECTIVE

Type 1 diabetes (T1D) is frequently associated with other autoimmune diseases (AIDs). Although most of T1D patients are sporadic cases (S-T1D), 10% to 15% have a familial form (F-T1D) involving 2 or more first-degree relatives. This study evaluated the effect of T1D family aggregation and age onset on AIDs occurrence.

METHODS

In this observational, cross-sectional, case-control, single center study, we enrolled 115 F-T1D and 115 S-T1D patients matched for gender, age, T1D age onset, and duration. With respect to T1D age onset (before or after 18 years), both groups were further subdivided into young- or adult-onset F-T1D and young- or adult-onset S-T1D. The presence of organ-specific antibodies and/or overt AIDs was evaluated.

RESULTS

The F-T1D group had a higher percentage of AIDs (29.8% vs 18.4%, P = .04) and a significant earlier onset of AIDs at Cox regression analysis (P = .04) than the S-T1D group. Based on multivariate analysis, the adult-onset F-T1D subgroup had the highest prevalence of both additional organ-specific antibodies (60.5%) and overt AIDs (34.9%), whereas the adult S-T1D subgroup was the least frequently involved (29.1% and 12.7%, respectively). In F-T1D patients, offsprings develop T1D and AIDs earlier than their parents do.

CONCLUSIONS

In T1D patients, familial aggregation and adult-onset of T1D increase the risk for coexistent AIDs. These clinical predictors could guide clinicians to address T1D patients for the screening of T1D-related AIDs.

Diabetes education in pediatrics: How to survive diabetes

Diabetes mellitus is the most common abnormal carbohydrate metabolism disorder affecting millions of people worldwide. It is characterized by hyperglycemia as a result of ß-cell destruction or dysfunction by both genetic and environmental factors. Over time chronic hyperglycemia leads to microvascular (i.e., retinopathy, nephropathy and neuropathy) and macrovascular (i.e., ischemic heart disease, peripheral vascular disease, and cerebrovascular disease) complications of diabetes. Diabetes complication trials showed the importance of achieving near-normal glycemic control to prevent and/or reduce diabetes-related morbidity and mortality. There is a staggering rate of increased incidence of diabetes in youth, raising concerns for future generations' health, quality of life and its enormous economic burden. Despite advancements in the technology, diabetes management remains cumbersome. Training individuals with diabetes to gain life-long survival skills requires a comprehensive and ongoing diabetes education by a multidisciplinary team. Diabetes education and training start at the time of diagnosis of diabetes and should be continuous throughout the course of disease. The goal is to empower the individuals and families to gain diabetes self-management skills. Diabetes education must be individualized depending on the individual's age, education, family dynamics, and support. In this article, we review the history of diabetes, etiopathogenesis and clinical presentation of both type 1 and type 2 diabetes in children as well as adolescents. We then focus on diabetes management with education methods and materials.

Leuconostoc mesenteroides fermentation produces butyric acid and mediates Ffar2 to regulate blood glucose and insulin in type 1 diabetic mice

Type 1 diabetic patients have lower counts of butyric acid-producing bacteria in the dysbiotic gut microbiome. In this study, we demonstrate that a butyric acid-producing Leuconostoc mesenteroides (L. mesenteroides) EH-1 strain isolated from Mongolian curd cheese can reduce blood glucose and IL-6 in the type 1 diabetic mouse model. L. mesenteroides EH-1 fermentation yielded high concentrations of butyric acid both in vitro and in vivo. Butyric acid or L. mesenteroides EH-1 increased the amounts of insulin in Min6 cell culture and streptozotocin (STZ)-induced diabetic mice. Inhibition or siRNA knockdown of free fatty acid receptor 2 (Ffar2) considerably reduced the anti-diabetic effect of probiotic L. mesenteroides EH-1 or butyric acid by lowering the level of blood glucose. We here demonstrate that Ffar2 mediated the effects of L. mesenteroides EH-1 and butryic acid on regulation of blood glucose and insulin in type 1 diabetic mice.

Prolactin protects against cytokine-induced beta-cell death by NFκB and JNK inhibition

Type 1 diabetes is caused by an autoimmune assault that induces progressive beta-cell dysfunction and dead. Pro-inflammatory cytokines, such as interleukin 1 beta (IL1B), tumor necrosis factor (TNF) and interferon gamma (IFNG) contribute for beta-cell death, which involves the activation of the nuclear factor kappa B (NFκB) and c- Jun N-terminal kinase (JNK). Prolactin (PRL), a physiological mediator for beta-cell proliferation, was shown to protect beta cells against cytokines pro-apoptotic effects. We presently investigated the mechanisms involved in the protective effects of prolactin against cytokine-induced beta-cell death. The findings obtained indicate that STAT3 activation is involved in the anti-apoptotic role of PRL in rat beta cells. PRL prevents the activation of JNK via AKT and promotes a shift from expression of pro- to anti-apoptotic proteins downstream of the JNK cascade. Furthermore, PRL partially prevents the activation of NFκB and the transcription of its target genes IkBa, Fas, Mcp1, A20 and Cxcl10 and also decreases NO production. On the other hand, the pro-survival effects of PRL do not involve modulation of cytokine-induced endoplasmic reticulum stress. These results suggest that the beneficial effects of PRL in beta cells involve augmentation of anti-apoptotic mechanisms and, at the same time, reduction of pro-apoptotic effectors, rendering beta cells better prepared to deal with inflammatory insults. The better understanding of the pro-survival mechanisms modulated by PRL in beta cells can provide tools to prevent cell demise during an autoimmune attack or following islet transplantation.

Cox-2 Expressed with Insulin in Pancreatic Beta-Cells, and in the Infiltrated Leukocytes in Inflamed Islets of Diabetic Mice

In the event of the onset of type 1 diabetes (T1D) the circulating autoantibodies against the beta-cell of the pancreas are attacked by macrophages and autoreactive lymphocytes under the influence of different cytokines. Eventually, beta-cells are destroyed through apoptosis, or natural killer cells, or a scavenger process. Cyclooxygenase (COX)-2 is constitutively expressed in beta-cells, the possible role in insulin secretion and insulitis has been suggested. However, COX-2 with lymphocytes and other infiltrated leukocytes on diabetogenesis remains largely elusive. We injected diabetic lymphocytes of non-obese diabetic (NOD) mice to NOD/SCID mice for adoptive transfer. The diabetogenesis of adoptive transferred NOD/SCID mice was tested with supplements of COX-2 inhibitor or the substrate, arachidonic acid, in the diets under placebo control. The tissues of intestine and pancreas of BALB/c, NOD and NOD/SCID mice were immunohistochemically analyzed. COX-2 and insulin were revealed in the vesicles of beta-cells in intact islets of BALB/c mice. The lymphocyte tracking of the transferred lymphocytes and COX-2 expression in beta-cells and emerged leukocytes showed that celecoxib, or the substrate did not change the pattern of lymphocyte accumulation in the pancreas compared to placebo, even though the development of severe diabetes was slightly different. COX-2 was only expressed in macrophages, rather than infiltrated lymphocytes. Morphology showed that the emerged lymphocytes migrated from outside islets indicating that the disructive impact of COX-2 on beta cells is probably limited. The enhanced expression of COX-2 and insulin in random beta-cells is likely associated with the genesis of diabetes, a possible mechanism to increase or extend insulin secretion in the late period of insulitis.

High frequency of vitamin D receptor gene polymorphism FokI in Brazilian Type 1 diabetes mellitus patients with clinical autoimmune thyroid disease

BACKGROUND

Polymorphisms of vitamin D receptor (VDR) gene have been studied as genetic markers of type 1 diabetes mellitus (T1DM) and some studies have reported associations with autoimmune thyroid disease. The aim of this study was to evaluate the relationship between VDR FokI polymorphism (rs10735810), thyroid autoimmunity and thyroid dysfunction (TD) in Brazilian T1DM.

METHODS

One-hundred-eighty T1DM patients were evaluated for age, duration of diabetes (DDM), positivity to TPO Antibody (TPOA), GAD Antibody (GADA), IA2 Antibody (IA2A) and fasting serum C-peptide (FCP) according to diagnosis of TD. PCR-RFLP analyses were carried out for VDR polymorphism FokI.

RESULTS

TPOA positivity (80.0 vs. 25.0 %, p < 0.001) and GADA positivity (56.0 vs. 30.3 %, p = 0.01) were higher in T1DM patients with TD with the same age and DDM than the group without TD, with no difference of FCP and IA2A positivity. We observed higher prevalence of VDR FokI in T1DM with TD (ff and Ff 73.9 % with TD vs. 52.7 % without TD, p = 0.05). Positivity to TPOA and presence of FokI polymorphism were significantly associated with the concurrence of TD in T1DM patients (OR 18.1; CI 3.7-87.0; p < 0.001).

CONCLUSIONS

The VDR FokI polymorphism (rs10735810) was associated to persistence of GADA, TPOA positivity and TD in Brazilian T1DM. Positivity to TPOA and VDR polymorphism FokI were strongly associated with concurrence of T1D and TD. These data collaborate to understanding the joint susceptibility genes for TD in T1DM.

Type 1 diabetes in NOD mice unaffected by mast cell deficiency

Mast cells have been invoked as important players in immune responses associated with autoimmune diseases. Based on in vitro studies, or in vivo through the use of Kit mutant mice, mast cells have been suggested to play immunological roles in direct antigen presentation to both CD4(+) and CD8(+) T cells, in the regulation of T-cell and dendritic cell migration to lymph nodes, and in Th1 versus Th2 polarization, all of which could significantly impact the immune response against self-antigens in autoimmune disease, including type 1 diabetes (T1D). Until now, the role of mast cells in the onset and incidence of T1D has only been indirectly tested through the use of low-specificity mast cell inhibitors and activators, and published studies reported contrasting results. Our three laboratories have generated independently two strains of mast cell-deficient nonobese diabetic (NOD) mice, NOD.Cpa3(Cre/+) (Heidelberg) and NOD.Kit(W-sh/W-sh) (Leuven and Boston), to address the effects of mast cell deficiency on the development of T1D in the NOD strain. Our collective data demonstrate that both incidence and progression of T1D in NOD mice are independent of mast cells. Moreover, analysis of pancreatic lymph node cells indicated that lack of mast cells has no discernible effect on the autoimmune response, which involves both innate and adaptive immune components. Our results demonstrate that mast cells are not involved in T1D in the NOD strain, making their role in this process nonessential and excluding them as potential therapeutic targets.

No effect of season of birth on risk of type 1 diabetes, cancer, schizophrenia and ischemic heart disease, while some variations may be seen for pneumonia and multiple sclerosis

Background: The risk of type 1 diabetes (T1DM), infections, cancer, schizophrenia and multiple sclerosis (MS) has been associated with environmental factors including vitamin D status.

Materials and Methods: Data were obtained from all children born in Denmark in 1940 (n = 72,839), 1977 (n = 89,570), and 1996 (n = 74,015). Information on contacts to hospitals (1977–2009) was obtained from the National Hospital Discharge Register. The main exposure variable was season of birth as a proxy variable for vitamin D status (summer: April–September and winter: October–March).

Results: No associations between season of birth and risk of MS were seen in the 1940 cohort or the 1996 cohort. In the 1977 cohort, there was a borderline statistically significant decreased risk of MS in those born during wintertime compared with those born during summertime (HR = 0.70, 95% CI: 0.47–1.04, p = 0.07). There were no significant differences within the groups regarding season and risk of T1DM at any age, T1DM before 10 y, infection, any type of cancer, schizophrenia and myocardial infarction. In the 1977 cohort the risk of pneumonia was significantly lower among those born in the summer compared with the winter at any age (HR 0.91, 95% CI 0.85–0.97, p < 0.01) and at age < 10 y (HR 0.90, 95% CI 0.84–0.97, p < 0.01).

Conclusion: MS and pneumonia in young subjects may be related to season of birth and thus maternal vitamin D exposure. Low sunlight exposure in the winter time leading to low vitamin D levels during pregnancy may be a potential explanation.

Temporal induction of immunoregulatory processes coincides with age-dependent resistance to viral-induced type 1 diabetes

The dilute plasma cytokine milieu associated with type 1 diabetes (T1D), while difficult to measure directly, is sufficient to drive transcription in a bioassay that uses healthy leukocytes as reporters. Previously, we reported disease-associated, partially IL-1 dependent, transcriptional signatures in both T1D patients and the BioBreeding (BB) rat model. Here, we examine temporal signatures in congenic BBDR.lyp/lyp rats that develop spontaneous T1D, and BBDR rats where T1D progresses only after immunological perturbation in young animals. After weaning, the BBDR temporal signature showed early coincident induction of transcription related to innate inflammation as well as IL-10- and TGF-β-mediated regulation. BBDR plasma cytokine levels mirrored the signatures showing early inflammation, followed by induction of a regulated state that correlated with failure of virus to induce T1D in older rats. In contrast, the BBDR.lyp/lyp temporal signature exhibited asynchronous dynamics, with delayed induction of inflammatory transcription and later, weaker induction of regulatory transcription, consistent with their deficiency in regulatory T cells. Through longitudinal analyses of plasma-induced signatures in BB rats and a human T1D progressor, we have identified changes in immunoregulatory processes that attenuate a preexisting innate inflammatory state in BBDR rats, suggesting a mechanism underlying the decline in T1D susceptibility with age.

Trichloroethylene Does Not Accelerate Autoimmune Diabetes in NOD Mice

Pre-existing or contributing risk factors, including genetic predisposition and environmental influences, are largely thought to play a crucial (though ill-elucidated) role in the development of autoimmunity. Trichloroethylene (TCE) is a widely used organic solvent, which has been suspected of increasing the prevalence of autoimmune diseases, e.g., lupus, following environmental contamination. Although few epidemiological data are available, several studies reported an accelerated and more severe disease in TCE-exposed autoimmunity-prone MRL(+/+) mice. To test whether TCE can exert similar deleterious effects on organ-specific autoimmune diseases, non obese diabetic (NOD) mice were given 5 mg/ml TCE via the drinking water for 12 weeks. TCE administration induced a decrease in CD44(+) splenic T-cells and CD45RB(high), CD54(+) blood and splenic T-cells. Conversely, the number of CD45RB(low) splenocytes was increased. Interestingly, the progressive increase in serum TNF-alpha and IFN-gamma levels normally seen with age in these mice was inhibited by TCE. There was also a relative lower incidence of histological changes in the pancreas of TCE-exposed NOD mice than in unexposed mice. Contrary to what has been found in systemic models of autoimmunity, TCE did not accelerate the diabetes of NOD mice and may have a protective effect. This finding suggests that comparative studies using different genetically related autoimmune-prone models are needed to investigate the role of xenobiotics in the precipitation of autoimmunity, particularly in sensitive populations.

Different roles of mast cells in obesity and diabetes: lessons from experimental animals and humans

Mast cells (MCs) play an important role in allergic hyperresponsiveness and in defending microorganism infections. Recent studies of experimental animals and humans have suggested that MCs participate in obesity and diabetes. MC distribution and activities in adipose tissues may vary, depending on the locations of different adipose tissues. In addition to releasing inflammatory mediators to affect adipose tissue extracellular matrix remodeling and to promote inflammatory cell recruitment and proliferation, MCs directly and indirectly interact and activate adipose tissue cells, including adipocytes and recruited inflammatory cells. Plasma MC protease levels are significantly higher in obese patients than in lean subjects. Experimental obese animals lose body weight after MC inactivation. MC functions in diabetes are even more complicated, and depend on the type of diabetes and on different diabetic complications. Both plasma MC proteases and MC activation essential immunoglobulin E levels are significant risk factors for human pre-diabetes and diabetes mellitus. MC stabilization prevents diet-induced diabetes and improves pre-established diabetes in experimental animals. MC depletion or inactivation can improve diet-induced type 2 diabetes and some forms of type 1 diabetes, but also can worsen other forms of type 1 diabetes, at least in experimental animals. Observations from animal and human studies have suggested beneficial effects of treating diabetic patients with MC stabilizers. Some diabetic patients may benefit from enhancing MC survival and proliferation – hypotheses that merit detailed basic researches and clinical studies.

Guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus

BACKGROUND

Multiple laboratory tests are used to diagnose and manage patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these tests varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for the use of laboratory testing for patients with diabetes. A new system was developed to grade the overall quality of the evidence and the strength of the recommendations. Draft guidelines were posted on the Internet and presented at the 2007 Arnold O. Beckman Conference. The document was modified in response to oral and written comments, and a revised draft was posted in 2010 and again modified in response to written comments. The National Academy of Clinical Biochemistry and the Evidence-Based Laboratory Medicine Committee of the American Association for Clinical Chemistry jointly reviewed the guidelines, which were accepted after revisions by the Professional Practice Committee and subsequently approved by the Executive Committee of the American Diabetes Association.

CONTENT

In addition to long-standing criteria based on measurement of plasma glucose, diabetes can be diagnosed by demonstrating increased blood hemoglobin A(1c) (HbA(1c)) concentrations. Monitoring of glycemic control is performed by self-monitoring of plasma or blood glucose with meters and by laboratory analysis of HbA(1c). The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of autoantibodies, urine albumin, insulin, proinsulin, C-peptide, and other analytes are addressed.

SUMMARY

The guidelines provide specific recommendations that are based on published data or derived from expert consensus. Several analytes have minimal clinical value at present, and their measurement is not recommended.

Analysis of pathogenesis of juvenile new-onset diabetes

BACKGROUND

Measurement of anti-islet autoantibodies at the time of disease onset contributes greatly to the differentiation of Type 1A diabetes with HLA Class II subtyping also contributing.

METHODS

Blood samples were obtained from 900 patients with age from 1 month to 25 years (median age 11.1 years) within 2 weeks of diabetes onset to test anti-islet autoantibodies to insulin (IAA), glutamic acid decarboxylase (GADA), insulinoma antigen (IA-2AA), the zinc transporter-8 (ZnT8AA), and islet-cell antibodies (ICA). Polymorphisms of the HLA Class II gene were typed in 547 randomly selected patients.

RESULTS

Of the 900 subjects analyzed, 145 (16.1%) were negative for all five anti-islet autoantibodies, and autoantibody negativity significantly increased with age: 10.2% (38/372) among children <10 years of age, 14.2% (46/325) in those 10-14 years of age, and 30.1% (61/203) in those >14 years of age (P < 0.001). The prevalence of IA-2AA was the highest among young children. The prevalence of GADA increased with age while the prevalence of IAA was inversely correlated with age. At diagnosis, the subjects with negative antibodies had a higher body mass index (P < 0.001) and less high risk HLA genotype DR3-DQ2/DR4-DQ8 (P < 0.01).

CONCLUSION

A large percentage of children and youths negative for all anti-islet autoantibodies at the onset of diabetes are likely to have the non-immune form, especially those without DR3/DR4 and obese patients. Among autoantibody-positive Type 1A patients, IAA and GADA showed a reciprocal prevalence, suggesting differential disease pathogenesis.

Guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus

BACKGROUND

Multiple laboratory tests are used to diagnose and manage patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these tests varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for the use of laboratory testing for patients with diabetes. A new system was developed to grade the overall quality of the evidence and the strength of the recommendations. Draft guidelines were posted on the Internet and presented at the 2007 Arnold O. Beckman Conference. The document was modified in response to oral and written comments, and a revised draft was posted in 2010 and again modified in response to written comments. The National Academy of Clinical Biochemistry and the Evidence Based Laboratory Medicine Committee of the AACC jointly reviewed the guidelines, which were accepted after revisions by the Professional Practice Committee and subsequently approved by the Executive Committee of the American Diabetes Association.

CONTENT

In addition to long-standing criteria based on measurement of plasma glucose, diabetes can be diagnosed by demonstrating increased blood hemoglobin A(1c) (Hb A(1c)) concentrations. Monitoring of glycemic control is performed by self-monitoring of plasma or blood glucose with meters and by laboratory analysis of Hb A(1c). The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of autoantibodies, urine albumin, insulin, proinsulin, C-peptide, and other analytes are addressed.

SUMMARY

The guidelines provide specific recommendations that are based on published data or derived from expert consensus. Several analytes have minimal clinical value at present, and their measurement is not recommended.

Therapeutic Strategies to Increase Human β-Cell Growth and Proliferation by Regulating mTOR and GSK-3/β-Catenin Pathways

This perspective delineates approaches to develop therapeutic strategies to stimulate the proliferative potential of adult human β-cells in vitro. Previous findings demonstrated that nutrients, through regulation of mTOR signaling, promote regenerative processes including DNA synthesis, cell cycle progression and β-cell proliferation in rodent islets but rarely in human islets. Recently, we discovered that regulation of the Wnt/GSK-3/β-catenin pathway by directly inhibiting GSK-3 with pharmacologic agents, in combination with nutrient activation of mTOR, was required to increase growth and proliferation in human islets. Studies also revealed that nuclear translocation of β-catenin in response to GSK-3 inhibition regulated these processes and was rapamycin sensitive, indicating a role for mTOR. Human islets displayed a high level of insulin resistance consistent with the inability of exogenous insulin to activate Akt and engage the Wnt pathway by GSK-3 inhibition. This insulin resistance in human islets is not present in rodent islets and may explain the differential requirement in human islets to inhibit GSK-3 to enhance these regenerative processes. Human islets exhibited normal insulin secretion but a loss of insulin content, which was independent of all treatment conditions. The loss of insulin content may be related to insulin resistance, the isolation process or culture conditions. In this perspective, we provide strategies to enhance the proliferative capacity of adult human β-cells and highlight important differences between human and rodent islets: the lack of a nutrient response, requirement for direct GSK-3 inhibition, insulin resistance and loss of insulin content that emphasize the physiological significance of conducting studies in human islets.

Prolonged survival and improved glycemia in BioBreeding diabetic rats after early sustained exposure to glucagon-like peptide 1

BACKGROUND

Type 1 diabetes (T1D) in both humans and BioBreeding (BB) rats is an autoimmune disease that results in complete destruction of islets and insulin dependency for life. Glucagon-like peptide 1 (GLP-1) promotes beta cell proliferation and neogenesis and has a potent insulinotropic effect. We hypothesized that the expression of GLP-1 before disease onset would increase islet mass, delay diabetes and prolong survival of BB rats.

METHODS

Vascular smooth muscle cells retrovirally transduced to secrete GLP-1 were seeded into TheraCyte encapsulation devices, implanted subcutaneously, and rats were monitored for diabetes.

RESULTS

In untreated control rats, plasma GLP-1 levels were 34.5-39.5 pmol/l, whereas, in treated rats, plasma levels were elevated, in the range 90-250.4 pmol/l. Hypoglycemia was not detected and this was anticipated from the glucose-regulated action of GLP-1. Diabetes onset (mean + or - SEM) in untreated rats occurred at 56.5 + or - 0.6 days (n = 6) and, in GLP-1-treated rats, was delayed until 76.4 + or - 3.3 days (n = 5) (p < 0.001). After disease onset, untreated control rats showed a rapid weight loss and elevated blood glucose (>650 mg/dl) and did not survive beyond 11 days. At 5 days after diabetes onset, insulin-secreting islets were absent in untreated rats. By contrast, treated rats maintained weight for up to 143 days of age and showed insulin-secreting beta cells.

CONCLUSIONS

Sustained GLP-1 expression delivered by encapsulated cells before diabetes onset in BB rats showed an improved clinical outcome, suggesting the potential for treating patients using long lasting GLP-1 analogs.

Anticytokine therapy, particularly anti-IFN-gamma, in Th1-mediated autoimmune diseases

Anticytokine therapy was proposed in 1974 in Nature, in which it was stated that hyperproduced interferon can cause autoimmune disease and anti-interferon can be therapeutic. In 1989, the use of antibodies to tumor necrosis factor-alpha in combination with antibodies to certain types of interferon was proposed to treat various autoimmune diseases, including AIDS. The first anticytokine therapy was conducted in 1975. Anti-interferon-gamma has brought improved and often striking results in the treatment of various T-helper 1-mediated autoimmune diseases, including inflammatory skin diseases. Anti-interferon-gamma may be a universal treatment for these conditions. In AIDS and other virus-induced autoimmune diseases, the virus may stimulate cytokines (interferons), which increase, rather than halt, viral replication. Tumor necrosis factor-alpha inhibitors have also shown good clinical results, however, they may result in complications and are ineffective in some autoimmune diseases.

Absence of p53-dependent apoptosis combined with nonhomologous end-joining deficiency leads to a severe diabetic phenotype in mice

OBJECTIVE

Regulation of pancreatic beta-cell mass is essential to preserve sufficient insulin levels for the maintenance of glucose homeostasis. Previously, we reported that DNA double-strand breaks (DSBs) resulting from nonhomologous end-joining (NHEJ) deficiency induce apoptosis and, when combined with p53 deficiency, progressed rapidly into lymphomagenesis in mice. Combination of NHEJ deficiency with a hypomorphic mutation, p53R172P, leads to the abrogation of apoptosis, upregulation of p21, and senescence in precursor lymphocytes. This was sufficient to prevent tumorigenesis. However, these mutant mice succumb to severe diabetes and die at an early age. The aim of this study was to determine the pathogenesis of diabetes in these mutant mice.

RESEARCH DESIGN AND METHODS

We analyzed the morphology of the pancreatic islets and the function, proliferation rate, and senescence of beta-cells. We also profiled DNA damage and p53 and p21 expression in the pancreas.

RESULTS

NHEJ-p53R172P mutant mice succumb to diabetes at 3-5 months of age. These mice show a progressive decrease in pancreatic islet mass that is independent of apoptosis and innate immunity. We observed an accumulation of DNA damage, accompanied with increased levels of p53 and p21, a significant decrease in beta-cell proliferation, and cellular senescence in the mutant pancreatic islets.

CONCLUSIONS

Combined DSBs with an absence of p53-dependent apoptosis activate p53-dependent senescence, which leads to a diminished beta-cell self-replication, massive depletion of the pancreatic islets, and severe diabetes. This is a model that connects impaired DNA repair and accumulative DNA damage, a common phenotype in aging individuals, to the onset of diabetes.

Upregulation of Fas and downregulation of CD94/NKG2A inhibitory receptors on circulating natural killer cells in patients with new-onset psoriasis

BACKGROUND

Psoriasis has been considered as a T-helper 1 cell-mediated autoimmune disease driven by collaboration with multiple components of innate and acquired immune cells. Natural killer (NK) cells have been shown to bridge innate and acquired immunity, and thus could potentially contribute to the pathophysiology of psoriasis.

OBJECTIVES

To investigate the phenotypic changes of circulating NK cells in patients with new-onset psoriasis.

METHODS

Fifteen patients with plaque psoriasis (eight women and seven men) who visited our clinic after their first episode of psoriasis and did not have a history of previous systemic therapy or phototherapy participated in this study. Peripheral blood mononuclear cells were isolated and stained with a panel of antibodies against cell surface receptors expressed on T and/or NK cells and analysed by flow cytometry.

RESULTS

As compared with normal healthy volunteers, patients with new-onset psoriasis showed no significant changes in numbers of peripheral NK, NK-T or T cells. NK activating receptors 2B4, CD48, NKG2D, CD16 and CD56 were found to be unchanged in new-onset psoriasis. However, the expression of Fas (activation-induced death receptor) was upregulated, whereas the expression of the NK inhibitory receptors CD94 and NKG2A was dramatically reduced on NK cells of new-onset psoriasis. These changes occurred at the level of mean fluorescent intensity, but minimally affected percentages of cells expressing Fas, CD94 and NKG2A.

CONCLUSIONS

Our findings demonstrate that changes in the expression of Fas and CD94/NKG2A receptors on NK cells may occur during new-onset psoriasis, and are likely to contribute to the pathogenesis of psoriasis.

Adenosine receptor activation ameliorates type 1 diabetes

Growing evidence indicates that adenosine receptors could be promising therapeutic targets in autoimmune diseases. Here we studied the role of adenosine receptors in controlling the course of type 1 diabetes. Diabetes in CD-1 mice was induced by multiple-low-dose-streptozotocin (MLDS) treatment and in nonobese diabetic (NOD) mice by cyclophosphamide injection. The nonselective adenosine receptor agonist 5'-N-ethylcarboxamidoadenosine (NECA) prevented diabetes development in both MLDS-challenged mice and in cyclophosphamide-treated NOD mice. The effect of NECA was reversed by the selective A2B receptor antagonist N-(4-cyanophenyl)-2-[4-(2,3,6,7-tetrahydro-2,6-dioxo-1,3-dipropyl-1H-purin-8-yl)phenoxy]acetamide (MRS 1754). The selective A1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA) and A3 receptor agonist N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (IB-MECA) were less efficacious in ameliorating the course of diabetes. NECA inhibited diabetes in A2A receptor KO mice and the selective A2A receptor agonist 2-p-(2-carboxyethyl)phenethyl-amino-5'-N-ethyl-carboxamidoadenosine (CGS21680) had no effect in normal mice, indicating a lack of role of A2A receptors. NECA failed to prevent cytokine-induced beta-cell death in vitro, but NECA strongly suppressed expression of the proinflammatory cytokines TNF-alpha, MIP-1alpha, IL-12, and IFN-gamma in pancreata, endotoxin, or anti-CD3-stimulated splenic cells, and T helper 1 lymphocytes, indicating that the beneficial effect of NECA was due to immunomodulation. These results demonstrate that adenosine receptor ligands are potential candidates for the treatment of type 1 diabetes.

HLA-DRB1*08 allele may help to distinguish between type 1 diabetes mellitus and type 2 diabetes mellitus in Mexican children

BACKGROUND

It may be difficult to distinguish type 1 diabetes mellitus (T1DM) from type 2 diabetes mellitus (T2DM) in the pediatric population. Autoantibodies may help to differentiate both types of diabetes, but sometimes these are positive in patients with T2DM and negative in patients with T1DM. The human leukocyte antigen (HLA)-DR genotype has been associated with T1DM and with T2DM only in adults and in determined cases.

AIM

To determine the differences in HLA class II allele frequencies in Mexican children with T1DM and T2DM.

METHODS

We included 72 children with T1DM, 28 children with T2DM, and 99 healthy controls. All were Mexican, and diabetes was diagnosed according to the clinical and laboratory criteria established by the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. The HLA-DRB1 typing was performed using polymerase chain reaction-sequence-specific oligonucleotide probe and polymerase chain reaction sequence-specific primers.

RESULTS

We found an increased frequency of HLA-DRB1*08 and a decreased frequency of HLA-DRB1*04 in the group with T2DM vs. T1DM [p = 0.0001, odds ratio (OR) = 10.58, 95% confidence interval (CI) = 3-40.8 and p = 0.0006, OR = 0.24, 95% CI = 0.11-0.53, respectively]. No significant differences were found between HLA-DRB1 alleles in T2DM vs. controls. In the group with T1DM, there was a significantly increased frequency of the HLA-DR4 and HLA-DR3 alleles relative to controls (p = 0.0000001, OR = 3.59, 95% CI = 2.2-5.8 and p = 0.00009, OR = 4.66, 95% CI = 2.1-10.3, respectively).

CONCLUSION

There are significant differences in the HLA profile in Mexican children with T1DM and T2DM. HLA typing could play a role in the differentiation between both types of diabetes in this population.

Signs of beta-cell autoimmunity in nondiabetic schoolchildren: a comparison between Russian Karelia with a low incidence of type 1 diabetes and Finland with a high incidence rate

OBJECTIVE

We sought to study the prevalence of autoantibodies to various islet cell antigens in the background population of two neighboring countries with a sixfold difference in the incidence of type 1 diabetes.

RESEARCH DESIGN AND METHODS

Serum samples were obtained from 3,652 nondiabetic schoolchildren in Finland and from 1,988 schoolchildren in the adjacent Karelian Republic of Russia. The Karelian children were divided into three groups (Finns/Karelians, Russians, and others) based on the ethnic background of their mother. The samples were analyzed for islet cell antibodies (ICAs), insulin autoantibodies (IAAs), GAD antibodies (GADAs), and the tyrosine phosphatase-like insulinoma antigen 2 (IA-2A) protein and HLA class II genotypes.

RESULTS

The frequency of ICAs, IAAs, and GADAs did not differ significantly between the Karelian (3.5, 0.6, and 0.9%, respectively) and Finnish children (2.8, 0.9, and 0.5%, respectively). Similarly, the frequency of multiple (> or = 2) autoantibodies was similar in both countries (0.5 vs. 0.6%). The frequency of IA-2A was, however, four times higher in Finland (0.6 vs. 0.15% in Russian Karelia; P = 0.03). There were no significant differences in autoantibody prevalence among the three ethnic groups in Russian Karelia. There was a falling frequency of GADAs and of positivity for multiple autoantibodies along with decreasing HLA-conferred disease susceptibility among the Finnish schoolchildren.

CONCLUSIONS

These data indicate that beta-cell autoimmunity among schoolchildren is as frequent in Russian Karelia as in Finland, although the incidence of clinical type 1 diabetes is six times higher in Finland. However, in contrast to this general trend, IA-2As were more common in Finland. Since IA-2As usually appear late in the preclinical process, this suggests that progressive beta-cell autoimmunity is more rare in Russian Karelia.

Diminished IFN-gamma response to diabetes-associated autoantigens in children at diagnosis and during follow up of type 1 diabetes

BACKGROUND

Imbalance of T-helper (Th)1- and Th2-like cytokines has been associated with type 1 diabetes. We therefore studied the immune deviation in antigen-specific T cells from diagnosis onwards in type 1 diabetic children.

METHODS

Peripheral blood mononuclear cells (PBMC) were collected from 15 children after 4 days, 3 months and 18 months of being diagnosed with type 1 diabetes, from 15 healthy children matched by age and gender to the type 1 diabetic children and from 14 children with and 35 children without HLA-risk genes. Secretion of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) was detected by ELISPOT after stimulation with glutamic acid decarboxylase (GAD(65), protein and aa 247-279), recombinant tyrosinphosphatase (IA-2), insulin, ovalbumin and phytohaemagglutinin (PHA).

RESULTS

Secretion of IFN-gamma in PBMC stimulated with GAD(65) (p < 0.05), the GAD(65)-peptide (p < 0.01), IA-2 (p < 0.01), and insulin (p < 0.01) was lower in diabetic children at diagnosis than in healthy children. Stimulation of PBMC with GAD(65) and IA-2 decreased the secretion of IFN-gamma in children with HLA-risk genotype. Spontaneous and antigen-induced IFN-gamma secretion increased significantly after diagnosis of the disease, but did not exceed the levels observed in healthy children. Fasting C-peptide levels at diagnosis correlated with insulin-induced IFN-gamma (R = 0.52; p = 0.05) and negatively with spontaneous IL-4 secretion (R = -0.62; p < 0.05).

CONCLUSION

A diminished IFN-gamma secretion and the association of fasting C-peptide levels with cytokine response in children with type 1 diabetes suggest that factors related to beta-cell function in type 1 diabetes may modify T-cell function. Thus, the T-cell responses detected at or after diagnosis may not reflect the pathogenic process leading to type 1 diabetes.

Vitamin D in type 1 diabetes prevention

Limited data from human observational studies suggest that early supplementation with 10 microg/d (400 IU/d) or less of vitamin D may not reduce the risk for type 1 diabetes but that doses of 50 microg/d (2000 IU/d) and higher may have a strong protective effect. Current U.S. recommendations (5-25 microg/d, 200-1000 IU/d) fall in the largely unstudied dose range in between. All infants and children should receive between 5 microg/d and 25 microg/d of supplemental vitamin D, particularly if they have limited sun exposure, live in northern areas, are exclusively breastfed, or are dark skinned. Caretakers of infants and children at increased risk of type 1 diabetes might wish to consider supplementation toward the upper end of that range or above. Additional studies are needed that 1) investigate the association between 25-hydroxyvitamin D and autoantibodies predictive of type 1 diabetes in infancy and beyond, 2) test the ability of vitamin D supplement doses between 5 and 50 microg/d to prevent autoantibodies and/or type 1 diabetes in infancy and beyond, and 3) examine the safety of vitamin D intakes of 25 microg/d and higher. Also, we need to consider the possible benefits of vitamin D supplementation when deciding whether or not to screen children for type 1 diabetes risk and to add type 1 diabetes to the growing list of outcomes that are considered when vitamin D recommendations are next revised.

Addison's disease presenting in four adolescents with type 1 diabetes

Primary adrenocortical insufficiency (Addison's disease) is a potentially fatal condition that often develops insidiously and can be easily overlooked. Although rare in the general population, it is more common in patients with type 1 diabetes mellitus (T1DM). The combination of Addison's disease with T1DM and/or autoimmune thyroid disease is known as autoimmune polyendocrine syndrome type-2 (APS-2). T1DM commonly precedes the development of adrenocortical insufficiency in most patients with APS-2. We, in this study, present four cases of Addison's disease developing in adolescents with pre-existing T1DM. Risk factors for Addison's disease in this population include a history of other organ-specific autoimmunity, particularly thyroid, and a positive family history. In addition to the 'classic' Addisonian features, the development of unexplained recurrent hypoglycemia, reduction in total insulin requirement, improvement in glycemic control, or abnormal pigmentation should arouse suspicion of adrenocortical insufficiency. Adrenal antibodies have been proposed as a screening tool for Addison's disease in the T1DM population, but doubts remain about their specificity and sensitivity. The addition of specific HLA DRB1 subtyping has been proposed to improve predictive value.

Oral Insulin Therapy to Prevent Progression of Immune-Mediated (Type 1) Diabetes

Repeated ingestion of insulin has been suggested as an immune tolerization therapy to prevent immune-mediated (type 1) diabetes. We performed a placebo-controlled, two-dose, oral insulin tolerance trial in newly diagnosed (< 2 years) diabetic patients who had required insulin replacement for less than 4 weeks and were found to have cytoplasmic islet cell autoantibodies (ICAs). No oral hypoglycemic agents were permitted during the trial. Endogenous insulin reserves were estimated at six-month intervals by plasma C-peptide responses to a mixed meal. Positive ICAs were found in 262 (31%) of the 846 patients screened. Of the 197 who agreed to participate, 187 could be followed for 6 to 36 months. Endogenous insulin retention was dependent upon initial stimulated C-peptide response, age at diabetes onset, and numbers of specific islet cell autoantibodies found. Oral insulin improved plasma C-peptide responses in patients diagnosed at ages greater than 20 years, best seen at the low (1 mg/day) over the high (10 mg/day) insulin dose (P = .003 and P = .01, respectively). In patients diagnosed before age 20 years, the 1 mg dose was ineffective, whereas the 10 mg dose actually accelerated C-peptide loss (P = .003). There were no adverse effects. If confirmed, these findings suggest that diabetic patients over age 20 years with ICA evidence of late-onset immune-mediated diabetes should be considered for oral insulin at 1 mg/day to better retain endogenous insulin secretion.

Canine and Feline Diabetes Mellitus: Nature or Nurture?

There is evidence for the role of genetic and environmental factors in feline and canine diabetes. Type 2 diabetes is the most common form of diabetes in cats. Evidence for genetic factors in feline diabetes includes the overrepresentation of Burmese cats with diabetes. Environmental risk factors in domestic or Burmese cats include advancing age, obesity, male gender, neutering, drug treatment, physical inactivity, and indoor confinement. High-carbohydrate diets increase blood glucose and insulin levels and may predispose cats to obesity and diabetes. Low-carbohydrate, high-protein diets may help prevent diabetes in cats at risk such as obese cats or lean cats with underlying low insulin sensitivity. Evidence exists for a genetic basis and altered immune response in the pathogenesis of canine diabetes. Seasonal effects on the incidence of diagnosis indicate that there are environmental influences on disease progression. At least 50% of diabetic dogs have type 1 diabetes based on present evidence of immune destruction of beta-cells. Epidemiological factors closely match those of the latent autoimmune diabetes of adults form of human type 1 diabetes. Extensive pancreatic damage, likely from chronic pancreatitis, causes approximately 28% of canine diabetes cases. Environmental factors such as feeding of high-fat diets are potentially associated with pancreatitis and likely play a role in the development of pancreatitis in diabetic dogs. There are no published data showing that overt type 2 diabetes occurs in dogs or that obesity is a risk factor for canine diabetes. Diabetes diagnosed in a bitch during either pregnancy or diestrus is comparable to human gestational diabetes.

Homeostatic expansion of T cells during immune insufficiency generates autoimmunity

During illness and stress, the immune system can suffer a considerable loss of T cells (lymphopenia). The remaining T cells undergo vigorous compensatory expansion, known as homeostatic proliferation, to reconstitute the immune system. Interestingly, human diseases of autoimmune etiology often present with immune deficiencies such as lymphopenia. In this study, we show that reduced T cell numbers and the resulting exaggerated homeostatic-type proliferation of T cells generate autoimmunity. The cycling T cell population is short lived, and the depleted memory compartment fuels the generation of new effector T cells. A catalyst for these phenomena is the increased responses to the cytokine IL-21, a mediator that regulates T cell turnover. We conclude that poor T cell survival and lymphopenia precipitate autoimmune disease.

In utero dietary exposures and risk of islet autoimmunity in children

OBJECTIVE

The goal of this study was to examine whether maternal dietary intake of vitamin D, omega-3 fatty acids, and omega-6 fatty acids during pregnancy is associated with the appearance of islet autoimmunity (IA) in offspring.

RESEARCH DESIGN AND METHODS

The Diabetes Autoimmunity Study in the Young (DAISY) is recruiting at birth and following children at increased risk for type 1 diabetes, as determined by HLA-DR genotype or by family history of type 1 diabetes. A total of 233 mothers of newly recruited DAISY subjects were asked to recall their intake of food and nutritional supplements during the third trimester of pregnancy using the Willett food frequency questionnaire. Children were followed for an average of 4 years (range 0.8-7.3 years) for the appearance of insulin, GAD(65), and IA-2 autoantibodies. Sixteen children developed at least one autoantibody during this period. Unadjusted and adjusted hazard ratios (HRs) for the development of IA were estimated with survival analysis using a Weibull distribution.

RESULTS

Maternal intake of vitamin D via food was significantly associated with a decreased risk of IA appearance in offspring, independent of HLA genotype, family history of type 1 diabetes, presence of gestational diabetes mellitus, and ethnicity (adjusted HR = 0.37; 95% CI 0.17-0.78). Vitamin D intake via supplements, omega-3 fatty acids, and omega-6 fatty acids intake during pregnancy were not associated with appearance of IA in offspring.

CONCLUSIONS

Our findings suggest that maternal intake of vitamin D through food during pregnancy may have a protective effect on the appearance of IA in offspring.

HLA-DRB1 andMICAin Autoimmunity

Autoimmune disorders such as type 1 diabetes (T1DM), celiac disease (CD), and Addison's disease (ADD) develop in individuals with genetic susceptibility that are exposed to environmental triggering factors not completely defined. Patients with an autoimmune disease (and their relatives) are at increased risk of developing another disorder, and this might be caused by a common genetic origin of autoimmunity; for example, HLA class II region in 6p21 shows a very strong association with most diseases. The aim of this study was to determine whether shared susceptibility markers extend from the central (DRB1) through the telomeric (MICA) HLA region. We analyzed three independent sets of families with one autoimmune disease, T1DM, CD, or ADD, and genotyped them for HLA-DRB1 and for the exon 5 GCT polymorphism of MICA. For HLA-DRB1, allele DRB1*0301 was the only one associated with risk for all three diseases; in the case of MICA, allele A9 was found to be the common protective allele. Haplotype analysis shows that haplotype A5.1-DRB1*0301 confers risk to autoimmunity. Our results show that there are common risk and protection alleles in both loci, suggesting a core of genetic association with autoimmunity (HLA-DRB1*0301 risk; A9 protection) that could be modulated by other alleles/loci or environmental factors toward one or another disease. Some alleles are part of conserved haplotypes (A5.1-DR3, A5.1-DR2), whereas others seem to have independent effect (A9) and support the idea of two independent loci in this region.

Inhibition of STAT4 Activation by Lisofylline Is Associated with the Protection of Autoimmune Diabetes

We investigated the signal transduction pathway of IL-12 and showed that lisofylline (LSF) inhibited the signal transducer and activator of transcription factor-4 (STAT4) activation. Interruption of IL-12-mediated STAT4 activation prevented autoimmune diabetes in NOD mice.

[LysB3, GluB29] insulin: a novel insulin analog with enhanced β-cell protective action

Insulin receptor substrate (IRS)-2 has been implicated in the promotion of beta-cell survival. Here we tested the hypothesis that the novel analog [LysB3, GluB29] insulin (insulin glulisine, IG) might mediate an enhanced beta-cell protective effect due to its unique property of preferential IRS-2 phosphorylation. We assessed IRS activation by IG and its anti-apoptotic activity against cytokines or palmitic acid in comparison to insulin, insulin analogs, and insulin-like growth factor (IGF)-I using INS-1 cells. IG induced a prominent IRS-2 activation without significant IRS-1 stimulation. The marked cytokine- and fatty acid-induced apoptosis was strongly (55-60%) inhibited by IG both at the level of caspase 3 activation and nucleosomal release, with only 15% inhibition of apoptosis by regular insulin. At 1nM, insulin, insulin aspart, and insulin lispro were much less effective compared to IG. In conclusion, the prominent anti-apoptotic activity of insulin glulisine might serve to counteract autoimmune- and lipotoxicity-induced beta-cell destruction.

Pancreatic-derived factor (FAM3B), a novel islet cytokine, induces apoptosis of insulin-secreting beta-cells

PANDER (PANcreatic DERived factor, FAM3B), a newly discovered secreted cytokine, is specifically expressed at high levels in the islets of Langerhans of the endocrine pancreas. To evaluate the role of PANDER in beta-cell function, we investigated the effects of PANDER on rat, mouse, and human pancreatic islets; the beta-TC3 cell line; and the alpha-TC cell line. PANDER protein was present in alpha- and beta-cells of pancreatic islets, insulin-secreting beta-TC3 cells, and glucagon-secreting alpha-TC cells. PANDER induced islet cell death in rat and human islets. Culture of beta-TC3 cells with recombinant PANDER had a dose-dependent inhibitory effect on cell viability. This effect was also time-dependent. PANDER caused apoptosis of beta-cells as assessed by electron microscopy, annexin V fluorescent staining, and flow-cytometric terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. PANDER did not affect cytosolic Ca(2+) levels or nitric oxide levels. However, PANDER activated caspase-3. Hence, PANDER may have a role in the process of pancreatic beta-cell apoptosis.

Circulating natural killer cells in psoriasis

BACKGROUND

Psoriasis is an immunologically mediated, probably autoimmune, disease in which T-helper type 1 cytokines play an important role. Established autoimmune diseases, with similar mechanistic characteristics to psoriasis, include multiple sclerosis, rheumatoid arthritis, type 1 diabetes mellitus and systemic lupus erythematosus. Natural killer (NK) and natural killer-T (NK-T) cells are considered key to the pathogenesis of these conditions, which are characterized by reduced numbers of NK cells in peripheral blood. NK and NK-T cells have been implicated in the pathogenesis of psoriasis and are present in plaques of psoriasis.

OBJECTIVES

To investigate whether levels of NK and NK-T cells are reduced in the peripheral blood of patients with psoriasis.

METHODS

Fourteen patients with untreated psoriasis, mean +/- SD age 46 +/- 13 years, and 13 healthy volunteers, mean +/- SD age 34 +/- 9 years, were venesected and peripheral blood mononuclear cells isolated, labelled with a panel of antibodies to T-cells and NK cells including CD3, CD56, CD57, CD16, CD94, CD158a, CD69 and cutaneous lymphocyte-associated antigen (CLA) and analysed using triple-colour flow cytometry.

RESULTS

There were significantly fewer cells expressing the NK-cell markers CD16 (P < 0.001), CD56 (P < 0.003), CD94 (P < 0.001) and CD158a (P < 0.02) in patients with psoriasis compared with normal controls. However, circulating numbers of NK-T cells (CD3+ CD56+ CD57+), T-cells (CD3+), activated lymphocytes (CD69+) or CLA+ cells were not significantly different between patients with psoriasis and controls.

CONCLUSIONS

Circulating NK cells are reduced in psoriasis. This finding is similar to those in established autoimmune diseases such as rheumatoid arthritis. This observation provides some evidence that psoriasis may be an autoimmune disease in which NK cells play a role.

IL-1beta and IFN-gamma induce the expression of diverse chemokines and IL-15 in human and rat pancreatic islet cells, and in islets from pre-diabetic NOD mice

AIMS/HYPOTHESIS

Cytokines and chemokines are important mediators of immune responses due to their ability to recruit and activate leukocytes. Using microarray analysis we observed that rat beta cells exposed to IL-1beta and IFN-gamma have increased mRNA levels of chemokines and IL-15. The aim of this study was to characterize the expression of IP-10, MIP-3alpha, fractalkine and IL-15 in rat beta cells, human pancreatic islets, and in islets isolated from NOD mice, both during the pre-diabetic period and following islet transplantation.

METHODS

FACS-purified rat beta cells and human islets were cultured with IL-1beta, IFN-gamma and/or TNF-alpha. Islets were isolated from NOD or BALB/c mice at different ages. For syngeneic islet transplantation, 2- or 3-week-old NOD islets were grafted under the kidney capsule of spontaneously diabetic NOD recipients. Chemokine and IL-15 mRNA expression and protein release were evaluated, respectively, by RT-PCR and ELISA.

RESULTS

Human islets and rat beta cells express IP-10, MIP-3alpha, fractalkine and IL-15 mRNAs upon exposure to cytokines. The expression of IL-15, IP-10 and fractalkine is regulated by IFN-gamma, while the expression of MIP-3alpha is IL-1beta-dependent. Moreover, cytokines induced IL-15, IP-10, Mig, I-TAC and MIP-3alpha protein accumulation in culture medium from human islets. In vivo, there was an age-related increase in IL-15, IP-10 and MIP-3alpha expression in islets isolated from NOD mice. Following syngeneic islet transplantation, increased expression of IL-1beta, IFN-gamma, fractalkine, IP-10, MCP-1 and MIP-3alpha mRNAs were observed in the grafts.

CONCLUSION/INTERPRETATION

Cytokine-exposed islets or beta cells express chemokines and IL-15. This could contribute to the recruitment and activation of mononuclear cells and development of insulitis in early Type 1 diabetes and during graft destruction.

Toward testing the hypothesis that group B coxsackieviruses (CVB) trigger insulin-dependent diabetes: inoculating nonobese diabetic mice with CVB markedly lowers diabetes incidence

Insulin-dependent (type 1) diabetes mellitus (T1D) onset is mediated by individual human genetics as well as undefined environmental influences such as viral infections. The group B coxsackieviruses (CVB) are commonly named as putative T1D-inducing agents. We studied CVB replication in nonobese diabetic (NOD) mice to assess how infection by diverse CVB strains affected T1D incidence in a model of human T1D. Inoculation of 4- or 8-week-old NOD mice with any of nine different CVB strains significantly reduced the incidence of T1D by 2- to 10-fold over a 10-month period relative to T1D incidences in mock-infected control mice. Greater protection was conferred by more-pathogenic CVB strains relative to less-virulent or avirulent strains. Two CVB3 strains were employed to further explore the relationship of CVB virulence phenotypes to T1D onset and incidence: a pathogenic strain (CVB3/M) and a nonvirulent strain (CVB3/GA). CVB3/M replicated to four- to fivefold-higher titers than CVB3/GA in the pancreas and induced widespread pancreatitis, whereas CVB3/GA induced no pancreatitis. Apoptotic nuclei were detected by TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) assay in CVB3/M-infected pancreata but not in CVB3/GA-infected pancreata. In situ hybridization detected CVB3 RNA in acinar tissue but not in pancreatic islets. Although islets demonstrated inflammatory infiltrates in CVB3-protected mice, insulin remained detectable by immunohistochemistry in these islets but not in those from diabetic mice. Enzyme-linked immunosorbent assay-based examination of murine sera for immunoglobulin G1 (IgG1) and IgG2a immunoreactivity against diabetic autoantigens insulin and HSP60 revealed no statistically significant relationship between CVB3-protected mice or diabetic mice and specific autoimmunity. However, when pooled sera from CVB3/M-protected mice were used to probe a Western blot of pancreatic proteins, numerous proteins were detected, whereas only one band was detected by sera from CVB3/GA-protected mice. No proteins were detected by sera from diabetic or normal mice. Cumulatively, these data do not support the hypothesis that CVB are causative agents of T1D. To the contrary, CVB infections provide significant protection from T1D onset in NOD mice. Possible mechanisms by which this virus-induced protection may occur are discussed.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

Background: Multiple laboratory tests are used in the diagnosis and management of patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially.

Approach: An expert committee drafted evidence-based recommendations for the use of laboratory analysis in patients with diabetes. An external panel of experts reviewed a draft of the guidelines, which were modified in response to the reviewers’ suggestions. A revised draft was posted on the Internet and was presented at the AACC Annual Meeting in July, 2000. The recommendations were modified again in response to oral and written comments. The guidelines were reviewed by the Professional Practice Committee of the American Diabetes Association.

Content: Measurement of plasma glucose remains the sole diagnostic criterion for diabetes. Monitoring of glycemic control is performed by the patients, who measure their own plasma or blood glucose with meters, and by laboratory analysis of glycated hemoglobin. The potential roles of noninvasive glucose monitoring, genetic testing, autoantibodies, microalbumin, proinsulin, C-peptide, and other analytes are addressed.

Summary: The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are of minimal clinical value at the present time, and measurement of them is not recommended.

Heme oxygenase-1 protects pancreatic beta cells from apoptosis caused by various stimuli

BACKGROUND

Several problems can occur after allogeneic islet transplantation: primary nonfunction, rejection, and the recurrence of autoimmune disease, which involve attack by the recipient's cytokines, T cells, natural killer cells, and monocytes on the donor's beta cells, which leads to beta-cell destruction. Recent studies have revealed that loss of transplanted islets is caused mainly by apoptosis. Heme oxygenase-1 (HO-1) is one of the antiapoptotic genes up-regulated under stress conditions. The aim of this work was to investigate any mechanisms of HO-1-mediated protection of beta cells from apoptosis.

METHODS

Apoptosis was assessed by comparison of viable transfected cells with and without apoptotic stimuli, and with and without HO-1 overexpression. Activation and function of p38 mitogen-activated protein kinase were determined using the specific inhibitor SB203580.

RESULTS

We have shown that HO-1 mediates antiapoptotic effects in beta cells. The percentage of apoptotic cells after stimulation with tumor necrosis factor a decreased from 75% without HO-1 to 5% when HO-1 was overexpressed. Our data indicate that HO-1 acts as a signal terminator of tumor necrosis factor alpha-induced apoptosis by modulation of the p38 mitogen-activated protein kinase pathway.

CONCLUSIONS

Profound cell stress that occurs in islets after transplantation, as well as at the onset of diabetes, results in beta-cell loss through apoptosis. Protection of beta cells by HO-1 improves their survival in vitro after various proapoptotic stimuli, suggesting that HO-1 suppresses one or several signaling pathways leading to apoptosis. We hypothesize that our in vitro findings can be extrapolated to the in vivo situation, and we propose that expression of HO-1 in islets may illuminate a valuable new approach to improving diabetes treatment.

Medical care from childhood to adulthood in type 1 and type 2 diabetes

Diabetes mellitus comprises a heterogeneous group of diseases that have in common the development of macro- and microvascular complications. It is now possible to identify subjects at high risk of Type 1 or Type 2 diabetes, especially in the patient's family members. Preventive interventions are quickly becoming available, and can help delay the onset of the disease and thereby reduce complications in these subjects. Furthermore the correct etiological diagnosis of diabetes is fundamental in providing the best treatment for the patient. Maturity-onset diabetes of the young (MODY) syndrome should be suspected in cases of a subtle onset of diabetes and autosomal dominant inheritance. Mitochondrial DNA mutations should be considered when a diabetic patient also suffers from deafness or if there is a family history of this combination in the mother side of the family. Atypical diabetes has to be identified by the physician to avoid mistakes when the patient enters the non-insulin-dependent phase. In the case of Wolfram's syndrome a gene analysis for each family member should be performed to identify heterozygote subjects. Recently, many discoveries in genetics help us better understand the pathogenesis of the diseases and diagnose the monogenic form of diabetes more easily. If all family members are followed in the same center, clues from the family history are readily available for differential diagnosis and preventive interventions can be established more effectively.

Insulin binds to glucagon forming a complex that is hyper-antigenic and inducing complementary antibodies having an idiotype-antiidiotype relationship

We demonstrate using physico-chemical techniques that insulin binds to glucagon with a Kd of 0.89 micromolar. While such binding is of little significance physiologically, it has important immunological consequences. Hormone binding is mirrored by specific binding between insulin antibody and glucagon antibody to form idiotype-antiidiotype complexes observable by Ouchterlony immunodiffusion and ELISA. These complexes may provide new insights into the formation of circulating immune complexes in diabetes. The insulin-glucagon complex is hyper-antigenic, inducing antibody production at concentrations that do not elicit immune responses from the individual hormones. The resulting immune response is not primarily against the individual hormones, but against the complex. In fact, all so-called insulin antibodies tested (rabbit, guinea pig, mouse and human) show substantially higher affinity for insulin-glucagon complex than for insulin alone, suggesting that this complex is the primary antigen in most, if not all, cases. These results lead to several testable predictions, including the possibility that glucagon antibody will bind to insulin receptors to cause type 2 (antibody mediated) insulin resistance.

Identification of novel cytokine-induced genes in pancreatic beta-cells by high-density oligonucleotide arrays

Type 1 diabetes is an autoimmune disease resulting from the selective destruction of insulin-producing beta-cells. Cytokines may contribute to pancreatic beta-cell death in type 1 diabetes. beta-cell exposure to interleukin (IL)-1beta induces functional impairment, whereas beta-cell culture for 6-9 days in the presence of IL-1beta and interferon (INF)-gamma leads to apoptosis. To clarify the mechanisms involved in these effects of cytokines, we studied the general pattern of cytokine-induced gene expression in beta-cells. Primary rat beta-cells were fluorescence-activated cell sorter-purified and exposed for 6 or 24 h to control condition, IL-1beta + INF-gamma, or IL-1beta alone (24 h only). Gene expression profile was analyzed in duplicate by oligonucleotide arrays. Nearly 3,000 transcripts were detected in controls and cytokine-treated beta-cells. Of these, 96 and 147 displayed changes in expression after 6 and 24 h, respectively, of exposure to IL-1beta + INF-gamma, whereas 105 transcripts were modified after a 24-h exposure to IL-1beta. The cytokine-responsive genes were clustered according to their biological functions. The major clusters observed were metabolism, signal transduction, transcription factors, protein synthesis/ processing, hormones, and related receptors. These modifications in gene expression may explain some of the cytokine effects in beta-cells, such as decreased protein biosynthesis and insulin release. In addition, there was induction of diverse cytokines and chemokines; this suggests that beta-cells may contribute to mononuclear cell homing during insulitis. Several of the cytokine-induced genes are potentially regulated by the transcription factor NF-kappaB. Clarification of the function of the identified cytokine-induced gene patterns may unveil some of the mechanisms involved in beta-cell damage and repair in type 1 diabetes.