Diagnosis of cyclic Cushing's disease manifests as early morning hyperglycemia in a patient with previously well-controlled type 1 diabetes

Background Cyclic Cushing's disease (CCD) is reported to occur in approximately 15% of patients with Cushing's disease (CD). CCD is a rare phenomenon in children. Case presentation A Portuguese female with well-controlled type 1 diabetes (T1DM) on an insulin pump developed transient uncontrolled blood sugar every morning. Increased basal and bolus insulin dosing was ineffective in lowering blood sugar and she began to miss school because of nausea, vomiting, fatigue, but no ketoacidosis. Therefore, other causes of sporadic hyperglycemia were explored. Multiple 6-h urinary free cortisol (UFC) samples revealed a spike in cortisol coincident with severe hyperglycemia. Pituitary magnetic resonance imaging (MRI) revealed a 3.5 mm microadenoma and inferior petrosal sinus sampling of adrenocorticotropic hormone (ACTH) after corticotropin releasing hormone (CRH) stimulation confirmed ACTH-dependent CD. Endoscopic endonasal tumor resection led to resolution of early morning hyperglycemia and symptoms. Discussion Our case illustrates an atypical presentation of CCD. There are no previous case reports of a pediatric patient with T1DM and CCD. Unexplained hyperglycemia in a patient with previous well-controlled T1DM should prompt assessment of other causes. CCD can be easily be missed if timed 6-h UFC measurements are not obtained.

Challenges to Reshape the Future of Type 1 Diabetes Research

CONTEXT

Immunotherapy trials to prevent type 1 diabetes have been unsuccessful for >15 years. Understanding pitfalls and knowledge gaps in the immunology of type 1 diabetes should lead us in new directions that will yield better trial outcomes. A proposal is made for precision medicine trial design in future type 1 diabetes studies.

EVIDENCE ACQUISITION

High-quality peer-reviewed basic science and clinical research trials for type 1 diabetes were used in this Perspective article. Type 1 diabetes publications were reviewed from 2000 to 2018 by using Google Scholar and PubMed reference databases.

EVIDENCE SYNTHESIS

Personalized medicine for type 1 diabetes should recognize that each individual has phenotypic and genotypic quirks that distinguish them from other study participants. A uniform protocol for antigen-specific immunotherapy has consistently failed to prevent disease. An alternative approach using molecular tools to personalize the preventive treatment strategy might be a road forward for type 1 diabetes research. Assumptions or lack of knowledge about disease stratification (not all type 1 diabetes is the same disease), individualized antigen-specific T cells, regulatory T-cell populations, and T-cell receptor rearrangement are just a few aspects of immunology that require integration with clinical trial design.

CONCLUSIONS

The type 1 diabetes research community continues to bring forward novel immunotherapy trials to prevent disease, but this approach is unlikely to succeed until several fundamental aspects of clinical immunology are recognized and addressed. Here, we identify several knowledge gaps that could rectify type 1 diabetes trial design and lead to future success.

TIMP-1 and CD82, a promising combined evaluation marker for PDAC

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a widely secreted protein that regulates cell motility, proliferation, and apoptosis. Although it is recognized that TIMP-1-tetraspanin CD63 regulates epithelial cell apoptosis and proliferation, how TIMP-1 controls cell motility is not well understood. In this study, we identify tetraspanin CD82 (also called KAI1) as a component of the promiscuous TIMP-1 interacting protein complex on cell surface of human pancreatic adenocarcinoma cells. CD82 directly binds to TIMP-1 N-terminal region through its large extracellular loop and co-localizes with TIMP-1 in both cancer cell lines and clinical samples. Moreover, CD82 facilitates membrane-bound TIMP-1 endocytosis, which significantly contributes to the anti-migration effect of TIMP-1. CD82 silencing partially eliminates these functions. TIMP-1 and CD82 expression status in patients with pancreatic ductal adenocarcinoma (PDAC) might demonstrate future usefulness as a differentiation marker and give us new insight into tumorigenic metastatic potential.

Transcription factor Ets-1 links glucotoxicity to pancreatic beta cell dysfunction through inhibiting PDX-1 expression in rodent models

AIMS/HYPOTHESIS

'Glucotoxicity' is a term used to convey the negative effect of hyperglycaemia on beta cell function; however, the underlying molecular mechanisms that impair insulin secretion and gene expression are poorly defined. Our objective was to define the role of transcription factor v-ets avian erythroblastosis virus E26 oncogene homologue 1 (Ets-1) in beta cell glucotoxicity.

METHODS

Primary islets and Min6 cells were exposed to high glucose and Ets-1 expression was measured. Recombinant adenovirus and transgenic mice were used to upregulate Ets-1 expression in beta cells in vitro and in vivo, and insulin secretion was assessed. The binding activity of H3/H4 histone on the Ets-1 promoter, and that of forkhead box (FOX)A2, FOXO1 and Ets-1 on the Pdx-1 promoter was measured by chromatin immunoprecipitation and quantitative real-time PCR assay.

RESULTS

High glucose induced upregulation of Ets-1 expression and hyperacetylation of histone H3 and H4 at the Ets-1 gene promoter in beta cells. Ets-1 overexpression dramatically suppressed insulin secretion and biosynthesis both in vivo and in vitro. Besides, Ets-1 overexpression increased the activity of FOXO1 but decreased that of FOXA2 binding to the pancreatic and duodenal homeobox 1 (PDX-1) homology region 2 (PH2), resulting in inhibition of Pdx-1 promoter activity and downregulation of PDX-1 expression and activity. In addition, high glucose promoted the interaction of Ets-1 and FOXO1, and the activity of Ets-1 binding to the Pdx-1 promoter. Importantly, PDX-1 overexpression reversed the defect in pancreatic beta cells induced by Ets-1 excess, while knockdown of Ets-1 prevented hyperglycaemia-induced dysfunction of pancreatic beta cells.

CONCLUSIONS/INTERPRETATION

Our observations suggest that Ets-1 links glucotoxicity to pancreatic beta cell dysfunction through inhibiting PDX-1 expression in type 2 diabetes.

Isolated double pituitary adenomas: A silent corticotroph adenoma and a microprolactinoma

We report a 27-year-old woman with amenorrhea and galactorrhea with mildly elevated serum prolactin levels. Her MRI demonstrated a cystic macroadenoma in the left aspect of the sella and a small microadenoma in the right aspect of the sella. Endoscopic transsphenoidal resection of the tumors revealed two histologically distinct tumors. The left tumor was consistent with a silent corticotroph macroadenoma and the right tumor was a prolactin producing microadenoma. Isolated double pituitary adenomas that are clearly separated by normal pituitary gland tissue are extremely rare. The incidence is approximately 0.37-2.6%. The coexistence of double adenomas can pose diagnostic and management challenges for the pituitary neuroendocrine team.

Systemic impact of intestinal helminth infections

In this review, we examine the evidence that intestinal helminths can control harmful inflammatory responses and promote homeostasis by triggering systemic immune responses. Induction of separable components of immunity by helminths, which includes type 2 and immune regulatory responses, can both contribute toward the reduction in harmful type 1 immune responses that drive certain inflammatory diseases. Despite inducing type 2 responses, intestinal helminths may also downregulate harmful type 2 immune responses including allergic responses. We consider the possibility that intestinal helminth infection may indirectly affect inflammation by influencing the composition of the intestinal microbiome. Taken together, the studies reviewed herein suggest that intestinal helminth-induced responses have potent systemic effects on the immune system, raising the possibility that whole parasites or specific molecules produced by these metazoans may be an important resource for the development of future immunotherapies to control inflammatory diseases.

Healthcare technician delivered screening of adults with diabetes to improve primary care provider recognition of depression

Purpose:

The purpose of this study was to implement a continuous quality improvement project aimed at improving primary care provider recognition of depression.

Materials and Methods:

A randomized, blinded, pre- and post-test design was implemented with 92 adults attending an academic internal medicine clinic. Subjects were assigned to an intervention where healthcare technicians (HCT) trained in the fundamentals of diabetes education delivered brief probing questions about self-care behavior and tailored talking points to encourage patients to talk to their primary care physician about their emotional health. The control group received a sham intervention that included only information on standards of diabetes care. Measures included both a paper-and-pencil screening of depression and the Primary Healthcare Questionnaire-8 (PHQ-8). Outcomes were evaluated for antidepressant and/or counseling treatment modalities once the possibility of depression was identified.

Results:

Both the control and intervention groups improved from pre-test to 3-month post-test scores on the PHQ-8 in clinically significant ways, but continued to have moderate to severe depression symptoms. There was a significant likelihood of receiving antidepressant therapy and/or counseling in those who scored high on the PHQ-8.

Conclusion:

HCT can be trained to talk to patients about emotional health issues during routine primary care visits. Depression screening measures can be administered as part of the triage routine at the start of a primary care visit, along with tasks such as vital signs. Answering a screening measure can help create awareness of symptoms and feelings that can prompt discussion during the patient–provider encounter that can result in the diagnosis and treatment of depression.

MicroRNA-24/MODY gene regulatory pathway mediates pancreatic β-cell dysfunction

Overnutrition and genetics both contribute separately to pancreatic β-cell dysfunction, but how these factors interact is unclear. This study was aimed at determining whether microRNAs (miRNAs) provide a link between these factors. In this study, miRNA-24 (miR-24) was highly expressed in pancreatic β-cells and further upregulated in islets from genetic fatty (db/db) or mice fed a high-fat diet, and islets subject to oxidative stress. Overexpression of miR-24 inhibited insulin secretion and β-cell proliferation, potentially involving 351 downregulated genes. By using bioinformatic analysis combined with luciferase-based promoter activity assays and quantitative real-time PCR assays, we identified two maturity-onset diabetes of the young (MODY) genes as direct targets of miR-24. Silencing either of these MODY genes (Hnf1a and Neurod1) mimicked the cellular phenotype caused by miR-24 overexpression, whereas restoring their expression rescued β-cell function. Our findings functionally link the miR-24/MODY gene regulatory pathway to the onset of type 2 diabetes and create a novel network between nutrient overload and genetic diabetes via miR-24.

Prevention of type 1 diabetes through infection with an intestinal nematode parasite requires IL-10 in the absence of a Th2-type response

Helminth infection can prevent type 1 diabetes (T1D); however, the regulatory mechanisms inhibiting disease remain largely undefined. In these studies, nonobese diabetic (NOD) IL-4(-/-) mice were infected with the strictly enteric nematode parasite, Heligmosomoides polygyrus. Short-term infection, 5-7 weeks of age, inhibited T1D onset, as late as 40 weeks of age. CD4(+) T-cell STAT6 phosphorylation was inhibited, while suppressed signal transducer and activator of transcription 1 phosphorylation was sustained, as were increases in FOXP3(-), CD4(+) T-cell interleukin (IL)-10 production. Blockade of IL-10 signaling in NOD-IL-4(-/-), but not in NOD, mice during this short interval abrogated protective effects resulting in pancreatic β-cell destruction and ultimately T1D. Transfer of CD4(+) T cells from H. polygyrus (Hp)-inoculated NOD IL-4(-/-) mice to NOD mice blocked the onset of T1D. These studies indicate that Hp infection induces non-T-regulatory cells to produce IL-10 independently of STAT6 signaling and that in this Th2-deficient environment IL-10 is essential for T1D inhibition.

Health-related quality of life, disease severity, and anticipated trajectory of diabetes

PURPOSE

Adults hospitalized with diabetes are likely to have multiple comorbid conditions contributing to suboptimal health-related quality of life. The purpose of this study was to survey urban, very low-income, hospitalized adults with diabetes about disease severity, anticipated disease trajectory, and self-rated health-related quality of life.

METHODS

Data were collected using the Brief Illness Perception Questionnaire, the 36-item Short Form Health Survey (SF-36), the comparative risk perception questionnaire, and glycosylated hemoglobin. Severity was defined by glycosylated hemoglobin level and current microvascular complications from diabetes.

FINDINGS

Those with more severe disease who also anticipated the development of additional diabetes-related complications were likely to have suboptimal physical and mental functioning. The perception of diabetes as a health threat concurrent with having non-diabetes-related comorbid chronic conditions contributed uniquely to explaining scores in health-related quality of life.

CONCLUSION

Hospitalized adults with diabetes represent a population affected by chronic disease demands that contribute to suboptimal physical and mental functioning. Suboptimal quality of life may contribute to severity of diabetes and to a perception of having a threatening disease trajectory. Hospitalization provides an opportunity for clinicians to intervene in mental and physical functioning by assessing for threatening illness perceptions and employing interventions to promote acceptance of functional limitations.

Afrocentric cultural values and beliefs: movement beyond the race and ethnicity proxy to understand views of diabetes

PURPOSE

The purpose of this study was to estimate the benefit of using a cultural characteristics scale to help diabetes educators understand how African Americans cope with diabetes. Illness representations are influenced by culture. Race and ethnicity as a proxy for culture provides an incomplete understanding of the mechanism by which cultural values influence representations of diabetes.

METHODS

A descriptive correlational design was employed by recruiting hospitalized adults with type 2 diabetes at 3 metropolitan northeast coast sites. The TRIOS Afrocentric cultural characteristics measure and the Illness perception Questionnaire were administered by paper-and-pencil to a diverse sample. Black race and African American ethnicity was used as a proxy for culture and compared to levels of agreement on an Afrocentric cultural scale to determine the relative ability to explain variance in illness representations of diabetes.

CONCLUSION

The TRIOS measure adapted to diabetes care explained variance in illness representations of diabetes, while African American ethnicity/black race was not able to explain variance in illness representations. Clinicians would benefit from considering the degree to which a patient identifies with particular cultural characteristics when tailoring interventions to manipulate illness representations that are not concordant with biomedical representations.

Short-term helminth infection inhibits type 1 diabetes independently of the Th2-type response (119.5)

Helminth infection can control a number of autoimmune inflammatory diseases in experimental models including type 1 diabetes (T1D).The molecular mechanisms of heminth mediated control of T1D are not yet determined,but it is generally thought that the associated immunoregulation is caused by the potent and highly polarized Th2-type response driven by IL-4.In these studies, nonobese diabetic (NOD) IL-4-/- mice were infected with a strictly enteric nematode parasite.Remarkably,we showed that the helminth-induced control of T1D remained intact. Elevations in CD4+ T cell STAT6 phosphorylation were inhibited,while suppression of STAT1 phosphorylation was sustained,as were increases in FOXP3-,CD4+T cell IL-10 production.Furthermore, protection still occurred if parasites were expulsed with an anti-helminth Rx after only two weeks infection.Oral antibiotic treatment did not effect helminth-mediated protection indicating that intestinal microbiota did not play a major role.Blockade of IL-10 signaling in NOD-IL-4-/-,but not NOD mice,during this short interval abrogated protective effects resulting in pancreatic β-cell destruction and T1D development.These studies indicate that helminth infection triggers multiple immune regulatory components that are induced and can act independently.Their combined effects help explain the potency of helminth-mediated control of pathologic inflammation and suggest future strategies for helminth-mediated therapeutic treatment of this autoimmune disease.

Ganglioside GM1 deficiency in effector T cells from NOD mice induces resistance to regulatory T-cell suppression

OBJECTIVE

To detect GM1 deficiency and determine its role in effector T cells (Teffs) from NOD mice in establishing resistance to regulatory T-cell (Treg) suppression.

RESEARCH DESIGN AND METHODS

CD4(+) and CD8(+) Teffs were isolated from spleens of prediabetic NOD mice for comparison with similar cells from Balb/c, C57BL/6, and NOR mice. GM1 was quantified with thin-layer chromatography for total cellular GM1 and flow cytometry for cell-surface GM1. Suppression of Teff proliferation was determined by application of GM1 cross-linking agents or coculturing with Tregs. Calcium influx in Teffs was quantified using fura-2.

RESULTS

Resting and activated CD4(+) and CD8(+) Teffs of NOD mice contained significantly less GM1 than Teffs from the other three mouse strains tested. After activation, NOD Teffs resisted suppression by Tregs or GM1 cross-linking agents in contrast to robust suppression of Balb/c Teffs; this was reversed by preincubation of NOD Teffs with GM1. NOD Teffs also showed attenuated Ca(2+) influx via transient receptor potential channel 5 (TRPC5) channels induced by GM1 cross-linking, and this, too, was reversed by elevation of Teff GM1.

CONCLUSIONS

GM1 deficiency occurs in NOD Teffs and contributes importantly to failed suppression, which is rectified by increasing Teff GM1. Such elevation also reverses subthreshold Ca(2+) influx via TRPC5 channels, an essential aspect of suppression. Our results also support a critical role for galectin-1 as a GM1 cross-linking counter-receptor that fittingly is upregulated and released by Tregs during activation. These findings suggest a novel mechanism by which pathogenic Teffs evade regulatory suppression, thereby leading to autoimmune β-cell destruction and type 1 diabetes.

Almond consumption and cardiovascular risk factors in adults with prediabetes

OBJECTIVE

The authors tested the hypothesis that in adults with prediabetes, an almond-enriched American Diabetes Association (ADA) diet improves measures of insulin sensitivity and other cardiovascular risk factors compared with an ADA nut-free diet.

METHODS

DESIGN

Randomized parallel-group trial.

SETTING

Outpatient dietary counseling and blood analysis.

SUBJECTS

Sixty-five adult participants with prediabetes.

INTERVENTION

Sixteen weeks of dietary modification featuring an ADA diet containing 20% of energy from almonds (approximately 2 oz per day).

MEASURES OF OUTCOME

Outcomes included fasting glucose, insulin, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, TC:HDL-C, and HbA1c, which were measured at weeks 0, 8, and 16. Body weight, body mass index (BMI), waist circumference, blood pressure, and nutrient intake were measured at weeks 0, 4, 8, 12, and 16.

RESULTS

The almond-enriched intervention group exhibited greater reductions in insulin (-1.78 µU/ml vs. +1.47 µU/ml, p  =  0.002), homeostasis model analysis for insulin resistance (-0.48 vs. +0.30, p  =  0.007), and homeostasis model analysis for beta-cell function (-13.2 vs. +22.3, p  =  0.001) compared with the nut-free control group. Clinically significant declines in LDL-C were found in the almond-enriched intervention group (-12.4 mg/dl vs. -0.4 mg/dl) as compared with the nut-free control group. No changes were observed in BMI (-0.4 vs. -0.7 kg/m(2), p  =  0.191), systolic blood pressure (-4.4 mm Hg vs. -3.5 mm Hg, p  =  0.773), or for the other measured cardiovascular risk factors.

CONCLUSIONS

An ADA diet consisting of 20% of calories as almonds over a 16-week period is effective in improving markers of insulin sensitivity and yields clinically significant improvements in LDL-C in adults with prediabetes.

Perceived risk of amputation, emotions, and foot self-care among adults with type 2 diabetes

PURPOSE

The purpose of this study was to determine the influence of having a family member who experienced an amputation on one's own perceived risk and fear of experiencing a diabetes-related amputation.

METHODS

This was a descriptive cross-sectional study using paper-and-pencil surveys by mail. Adults with type 2 diabetes and a family history of diabetes attending a self-management education program in the Metropolitan New York/New Jersey area were recruited. Measures were completed about risk perception and fear of amputation, emotional representations of diabetes from the Illness Perception Questionnaire, and the foot self-care behavior component of the Summary of Diabetes Self-care Activities Survey. The authors estimated the variability in foot self-care that was accounted for by risk perception and fearful memories.

RESULTS

In those who remembered a family member needing an amputation, high perceived risk and fear was associated with less routine foot self-care. For those without family history of amputation, fear was positively associated with foot self-care.

CONCLUSIONS

Motivation for foot self-care behavior may be driven by risk perception and emotional responses. The ways in which risk perception and fear influence motivation for preventive foot self-care behavior are influenced by whether one's family member was affected by an amputation. Probing about the influence of the patient's legacy of diabetes may be helpful when customizing education plans.

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.

Prevention of Type 1 diabetes in NOD mice by helminth infection (131.36)

Parasitic helminth infection has been shown to modulate pathologic inflammation associated with allergy and autoimmune disease. The aim of this study was to examine whether infection with a helminth parasite could down-regulate the onset of type 1 diabetes in NOD mice and to examine the mechanisms involved in this protection. At 5 weeks of age, NOD mice were infected with Heligmosomoides polygyrus(Hp). At 36 weeks of age, these mice were compared with uninfected mice for the onset of type 1 diabetes (T1D). 70% of uninfected NOD mice became diabetic but only 10% of Hp infected mice developed T1D. Moreover, Hp infection also significantly reduced the development of the more aggressive cyclophosphamide-induced T1D in NOD mice with 5% developed in Hp-infected group compared to 78% in uninfected group. Further studies showed that infection with Hp in NOD mice:

markedly inhibited insulitis in the pancreas;elevated IL-4 and IL-13 levels in mesenteric and pancreatic lymph nodes as well as in spleens;increased the frequency of CD4+ CD25+ Foxp3+ Tregs in mesenteric and pancreatic lymph nodes;led to a consistent, massive accumulation of mononuclear cells in the regions of pancreatic fat.

These findings suggest that infection with Hp significantly inhibits the onset of T1D in NOD mice by influencing lymphocyte trafficking to the β-islet cells in the context of increased Th2 and T regulatory cell populations.

Tissue inhibitor of metalloproteinase-2 inhibits T-cell infiltration and preserves pancreatic β-cell function in an in vitro type 1 diabetes mellitus model

Type 1 diabetes mellitus (T1DM) results from autoreactive T-cells that attack and destroy insulin producing pancreatic beta-cells. This knowledge has provided a framework for numerous efforts to prevent or mitigate T1DM at various stages of the disease. In this study, we utilized an organ culture model of type 1 diabetes to determine whether tissue inhibitors of metalloproteinases (TIMPs) could block T-cell migration into the pancreas and ultimately preserve beta-cell function. We measured T-cell repertoires, insulin secretion, and performed immunohistochemistry and confocal laser microscopy in order to evaluate the effect of TIMP-1, TIMP-2, and TIMP-3 on our in vitro T1DM organ culture model. TIMP-2 decreased T-cell transmigration and preserved insulin production in our T1DM organ culture model. Moreover, TIMP-2 inhibited transmigration of diabetogenic T-cells across an islet microvascular endothelial cell layer. Our findings suggest that TIMP-2 is effective at blocking infiltration of autoreactive T-cells into target pancreas tissue thereby preserving pancreatic beta-cell mass.

Transcriptional Regulation of Cyclooxygenase-2 Gene in Pancreatic β-Cells

Prostaglandin E(2) (PGE(2)) has been shown to negatively affect pancreatic beta-cell function, and its inducible synthesis is mediated in part by cycloxygenase-2 (COX-2). Regulation of basal and inducible COX-2 gene expression in pancreatic beta-cells is not fully understood. In this report, we used pancreatic beta-cells (RINm5F) to explore the molecular mechanisms regulating COX-2 promoter activity. Through deletion analysis of a -907/+70-bp 5' upstream region of the mouse COX-2 gene, we identified an inhibition domain (-804/-371) and an activation domain (-371/+70). The highest promoter activity was seen when the promoter was reduced to -371 bp. Several cis-acting elements were selected for site-directed mutations in the activation domain. We identified three sites that were essential for basal COX-2 promoter activity: 1) CCAAT/enhancer-binding protein (C/EBP), 2) aryl hydrocarbon receptor (AhR), and 3) cAMP response element-binding protein (CREB). Single mutation of each individual site inhibited 70-80% of basal COX-2 promoter activity. Double mutation of the AhR and CREB-binding sites showed synergy in repressing COX-2 promoter activity as did mutation of all three sites. We demonstrated that the transcription factors from RINm5F nuclear extracts specifically bound to oligonucleotides containing C/EBP, AhR, or CREB consensus sites. Forskolin, an activator of adenyl cyclase, increased COX-2 promoter activity via the CREB site. COX-2 promoter activity was also increased by 2,3,7,8-tetrachlorodibenzo-p-dioxin, an AhR activator, through the AhR site. Both forskolin and 2,3,7,8-tetrachlorodibenzo-p-dioxin increased COX-2 mRNA in a dose-dependent manner. We consider these three transcriptional regulators of COX-2 expression to be potential targets for the prevention of beta-cell damage mediated by PGE(2).

Induction of cyclooxygenase-2 gene in pancreatic beta-cells by 12-lipoxygenase pathway product 12-hydroxyeicosatetraenoic acid

Cyclooxygenase-2 (COX-2) gene and 12-lipoxygenase (12-LO) gene are preferentially expressed over other types of cyclooxygenase and lipoxygenase in pancreatic beta-cells. Inhibition of either COX-2 or 12-LO can prevent cytokine-induced pancreatic beta-cell dysfunction as defined by inhibition of glucose-stimulated insulin secretion. As cellular stress induces both genes and their respective end products in pancreatic beta-cells, we evaluated the role of 12-hydroxyeicosatetraenoic acid (HETE) on COX-2 gene expression, protein expression, and prostaglandin E2 (PGE2) production. We demonstrate that 12-HETE significantly increases COX-2 gene expression and consequent product formation, whereas a closely related lipid, 15-HETE, does not. In addition, IL-1beta-stimulated prostaglandin E2 production is completely inhibited by a preferential lipoxygenase inhibitor cinnaminyl-3,4-dihydroxy-alpha-cyanocinnamate. We then evaluated IL-1beta-induced PGE2 production in islets purified from control C57BL/6 mice and 12-LO knockout mice lacking cytokine-inducible 12-HETE. IL-1beta stimulated an 8-fold increase in PGE2 production in C57BL/6 islets but failed to stimulate PGE2 in 12-LO knockout islets. Addition of 12-HETE to 12-LO knockout islet cells produced a statistically significant rise in PGE2 production. Furthermore, 12-HETE, but not 15-HETE, stimulated COX-2 promoter and activator protein-1 binding activity. These data demonstrate that 12-HETE mediates cytokine-induced COX-2 gene transcription and resultant PGE2 production in pancreatic beta-cells.

Tissue inhibitor of metalloproteinase-1 prevents cytokine-mediated dysfunction and cytotoxicity in pancreatic islets and beta-cells

In addition to inhibiting matrix metalloproteinase-2 and matrix metalloproteinase-9 activity, recent studies suggest that tissue inhibitor of metalloproteinase (TIMP)-1 may inhibit apoptosis in various cell lines. To address this question in pancreatic islets and beta-cells, we treated rat pancreatic islets and INS-1 cells with a high-dose combination of the cytokines interleukin (IL)-1beta, tumor necrosis factor-alpha, and interferon-gamma with or without the addition of TIMP-1 and TIMP-2 protein. Using flow cytometry, we quantitated DNA fragmentation to assess cellular apoptosis and confirmed these observations with DNA laddering experiments. Next, we transfected the mouse TIMP-1 gene into INS-1 cells and performed Western immunoblotting to demonstrate expression of TIMP-1 protein. We treated TIMP-1-expressing INS-1 cells with high-dose cytokines and again used flow cytometry to assess DNA fragmentation. We also evaluated the effect of TIMP-1 on IL-1beta-induced inhibition of glucose-stimulated insulin secretion (GSIS) in freshly isolated rat pancreatic islets. Finally, we evaluated the effect of TIMP-1 on inducible nitric oxide synthase (iNOS) gene expression and nuclear factor (NF)-kappaB activity in INS-1 cells stimulated with high-dose cytokines. TIMP-1 but not TIMP-2 prevented cytokine-induced apoptosis and cytokine-mediated inhibition of GSIS in rat islets and beta-cells. TIMP-1 mediated these effects by inhibiting cytokine activation of NF-kappaB, but it did not affect nitric oxide production or iNOS gene expression. Therefore, TIMP-1 may be an ideal gene to prevent cytokine-mediated beta-cell destruction and dysfunction in models of type 1 diabetes and islet transplantation rejection.

Adeno-associated virus vector mediated gene transfer to pancreatic beta cells

Insulin-dependent diabetes mellitus (IDDM) or type 1 diabetes is an autoimmune disease that results in destruction of the insulin-producing pancreatic islet beta cells. Several factors induce the invasion of immune cells into islets and trigger inflammation. Gene therapy approaches targeting the islet cells could be an effective treatment to prevent the onset or reverse type 1 diabetes. Allogeneic islet transplantation provides short-term treatment. However, genetically modified islets, which resist the host immune response, could provide long-term solutions. Adeno-associated virus (AAV) is emerging as a prominent vector system for delivering therapeutic genes for human gene therapy. AAV vector can transduce nondividing cells and provide long-term gene expression by integrating into host chromosome. Therefore, it is an appropriate vector system for islet cell gene therapy. To test the efficacy of AAV vector to transduce pancreatic endocrine cells, we constructed AAV vectors using plasmid pSub201. Wild-type AAV DNA analogue from plasmid psub201 was subcloned into a cloning plasmid pSP72 and AAV vectors were constructed by inserting the transgenes with heterologous promoter in place of AAV open reading frames (rep and cap). In this report we demonstrate the transduction of pancreatic islet cells with AAV vectors encoding bacterial -galactosidase enzyme or enhanced green fluorescent protein (EGFP) as reporter gene. Dispersed porcine and rat islet cells can be transduced by AAV vector, with an efficiency of 47% and 38%, respectively. In particular porcine islet insulin producing beta cells were transduced with an efficiency of 39%. Intact rat islet cells were transduced with an efficiency of 26% as estimated by FACS analysis following transduction with an AAV vector encoding EGFP. Transduction of intact rat islets with an AAV vector did not alter glucose-induced insulin secretion. AAV vector transduction was higher in transformed islet cell lines INS-1 and RIN m5F with an efficiency of 65% and 57%, respectively. These new results suggest that AAV vectors will provide an improved method of gene delivery to pancreatic islets and isolated pancreatic beta cells.

Sera from children with type 1 diabetes mellitus react against a new group of antigens composed of lysophospholipids

Several autoantibodies related to Type 1 diabetes mellitus and their corresponding autoantigens have been previously identified. While peptide antigens are more widely recognized, lipid antigens like sulfatides and gangliosides are also known epitopes for the diabetic humoral immune response. Islet cell antibodies (ICA) in Type 1 diabetes are heterogeneous immunoglobulins directed against selected antigens in the islets of Langerhans. Moreover, ICA may be the best predictive marker of disease in family members of patients with Type 1 diabetes. The aims of this study were: (1) to purify lipids from porcine pancreas that contain ICA epitopes; (2) to characterize these lipid antigens, and (3) to use the purified lipids in an assay to detect antibodies in patients with Type 1 diabetes. A unique family of 4 lysophospholipids, 1 fully characterized as lysophosphatidylmyoinositol, partially inhibited ICA staining, and therefore, were considered to be candidate antigens for an ICA immunoassay. Using a dot blot immunoassay, we detected antibodies directed against these phospholipids in 28 out of 46 (61%) diabetic sera, while detecting only 1 false positive out of 28 nondiabetic sera (3.6%; p < 0.0001 comparing diabetic vs. nondiabetic serum). Therefore, lysophospholipid immunoassay positivity is present in sera of Type 1 diabetic patients. Furthermore, we detected 15 out of 23 ICA-negative diabetic sera (65.2%), showing that our phospholipid immunoassay does not correlate with ICA positivity.

Resistance to type 1 diabetes induction in 12-lipoxygenase knockout mice

Leukocyte 12-lipoxygenase (12-LO) gene expression in pancreatic beta cells is upregulated by cytotoxic cytokines like IL-1beta. Recent studies have demonstrated that 12-LO inhibitors can prevent glutamate-induced neuronal cell death when intracellular glutathione stores are depleted. Therefore, 12-LO pathway inhibition may prevent beta-cell cytotoxicity. To evaluate the role of 12-LO gene expression in immune-mediated islet destruction, we used 12-LO knockout (12-LO KO) mice. Male homozygous 12-LO KO mice and control C57BL/6 mice received 5 consecutive daily injections of low-dose streptozotocin to induce immune-mediated diabetes. Fasting serum glucose and insulin levels were measured at 7-day intervals, and the mice were followed up for 28 days. 12-LO KO mice were highly resistant to diabetes development compared with control mice and had higher serum insulin levels on day 28. Isolated pancreatic islets were treated with IL-1beta, TNF-alpha, and IFN-gamma for 18 hours. Glucose-stimulated insulin secretion in cytokine-treated islets from C57/BL6 mice decreased 54% from that of untreated islets. In marked contrast, the same cytokine mix led to only a 26% decrease in islets from 12-LO KO mice. Furthermore, cytokine-induced 12-hydroxyeicosatetraenoic acid (12-HETE) production was absent in 12-LO KO islets but present in C57/BL6 islets. Isolated peritoneal macrophages were stimulated for 48 hours with IFN-gamma + LPS and compared for nitrate/nitrite generation. 12-LO KO macrophages generated 50% less nitrate/nitrite when compared with C57BL/6 macrophages. In summary, elimination of leukocyte 12-LO in mice ameliorates low dose streptozotocin-induced diabetes by increasing islet resistance to cytokines and decreasing macrophage production of nitric oxide.

The role of 12-lipoxygenase in pancreatic -cells (Review)

Leukocyte type 12-lipoxygenase (12-LO) catalyzes the conversion of arachidonic acid (AA; C20:4) to 12-hydroperoxyeicosatetraenoic acid (12-HPETE) and linoleic acid (LA; C18:2) to 13-hydroperoxyoctadecadienoic acid (13-HPODE). Previous studies have demonstrated that 12-LO, but not 5- or 15-lipoxygenase (5-LO, 15-LO respectively), is specifically expressed in pancreatic -cells and is involved in regulating glucose-stimulated insulin secretion. Lipoxygenase products also have been linked with inflammatory pathways in endothelial cells, kidney mesangial cells, inflammatory bowel disease, and corneal epithelial cells. Therefore, 12-LO may play a role in cytokine mediated inflammation in pancreatic beta-cells (i.e. beta -cell dysfunction and cytotoxicity). Cytokines such as IL-1 stimulate both de novo 12-LO protein synthesis and enzyme activity in pancreatic beta-cells. The products generated by 12-LO may ultimately be involved in cellular events that lead to lipid peroxidation. Hydroperoxide and free radical production in beta-cells can activate intracellular signaling pathways that lead to cell death or may directly damage mitochondrial and plasma membranes. Increased 12-LO expression has also been found in islets from prediabetic Zucker fatty rats, a model that demonstrates insulin secretory defects similar to human type 2 diabetes. In this review, we present an overview of the 12-LO pathway in regulating glucose-stimulated insulin secretion in beta-cells as well as more recent data which supports the hypothesis that the 12-LO pathway participates in cytokine mediated beta-cell dysfunction and cytotoxicity.

The stress-activated c-Jun protein kinase (JNK) is stimulated by lipoxygenase pathway product 12-HETE in RIN m5F cells

Cytokine induced pancreatic beta-cell destruction seen in Type 1 diabetes and islet graft rejection involves multiple intracellular signaling pathways that directly or indirectly lead to inflammatory damage or programmed cell death. IL-1beta has been shown to stimulate the 12-lipoxygenase pathway product 12-HETE, in RIN m5F cells; however, the precise role of 12-LO activation in mediating cytokine effects is not clear. Since the stress-activated protein kinase, JNK, has been linked to cytokine mediated inflammatory actions, we studied the effect of two LO products, 12-HETE and 15-HETE, on JNK activity. We demonstrate that 1 nM 12-HETE stimulates JNK activity, while 1 nM 15-HETE, the 15-lipoxygenase pathway product, does not. These results suggest 12-HETE is a novel upstream signal for IL-1beta induced JNK activation in RIN m5F cells.

Lisofylline, an inhibitor of unsaturated phosphatidic acid generation, ameliorates interleukin-1 beta-induced dysfunction in cultured rat islets

Interleukin-1 beta (IL-1 beta) causes rat islet cell dysfunction through mechanisms that involve inducible nitric oxide synthase (iNOS). However, IL-1 beta also activates several lipid pathways, including those generating phosphatidic acid (PA). Lisofylline (LSF), a water-soluble, nontoxic, selective inhibitor of the PA-1 alpha subspecies, which is stimulated by IL-1 beta and tumor necrosis factor-alpha, has been shown to prevent cytokine-induced cytotoxicity in in vivo animal models. To evaluate the effect of LSF on acute IL-1 beta-induced islet dysfunction, rat islets were exposed to IL-1 beta (0.1 ng/ml) with or without LSF (100 microM) for 24 h, followed by 25 mM glucose (G) stimulation, measurement of rat insulin by RIA, and calculation of the insulin secretion rate. In other experiments, rat islets were precultured for 48 h, then treated for 48 h in 25 mM G with or without IL-1 beta (0.1 ng/ml) and LSF (400 microM), and aliquots of medium were removed at 0, 24, and 48 h for measurement of rat insulin. In addition, islets were exposed to 25 mM G with or without IL-1 beta and LSF, lipids were then extracted, and PA subspecies were identified by TLC and mass spectroscopy, and quantitated using normal phase HPLC. Islets were also exposed to IL-1 beta with or without LSF, and Western immunoblots were performed to evaluate the effect of LSF on iNOS protein expression. IL-1 beta caused a 44% decrease in islet G-stimulated insulin secretion compared to that in untreated islets (P < 0.0005), which was totally reversed by LSF. In addition, IL-1 beta decreased the G-stimulated medium insulin content by 75% at 24 h (P = 0.0004) and 86% at 48 h compared to that in control islets (P < 0.0001). LSF-treated islets maintained 70% of medium insulin content at 24 h (P = 0.11) and 50% at 48 h (P < 0.0001) compared to control islets. HPLC quantitation of PA-1 alpha extracted from islets treated with IL-1 beta alone showed an approximately 15-fold increase over the PA-1 alpha content of islets treated with IL-1 beta and LSF. IL-1 beta-induced expression of iNOS was unchanged with the addition of LSF. These results suggest that LSF is effective in reducing IL-1 beta-induced islet dysfunction, thus supporting the role of lipid mediators such as PA in cytokine-induced islet toxicity.

Interleukin-1 beta regulates the expression of a leukocyte type of 12-lipoxygenase in rat islets and RIN m5F cells

The leukocyte type of 12-lipoxygenase (12-LO) may play a role in inflammatory reactions in many cell types through the conversion of arachidonic acid to proinflammatory eicosanoids that include 12-hydroperoxyeicosatetraenoic acid and 12-hydroeicosatetraenoic acid. Previous studies demonstrating the presence of a functional 12-LO pathway in rat and human pancreatic beta-cells plus the recent cloning of a rat leukocyte type of 12-LO allowed us to evaluate whether inflammatory cytokines such as interleukin-1 beta (IL-1 beta) can regulate the beta-cell 12-LO enzyme pathway, thus providing a potential link between the cytotoxic effects of cytokines on pancreatic beta-cells and the proinflammatory effects of 12-LO products. We demonstrate that IL-1 beta induces 12-LO protein and messenger RNA (mRNA) expression in RIN m5F cells and 12-LO mRNA expression in rat islets. RIN m5F cells treated for 16 h with IL-1 beta (25, 50, and 100 ng/liter) showed a maximal 2-fold increase in the expression of a leukocyte form of 12-LO demonstrated by Western blots. A concomitant increase in 12-LO mRNA expression was seen at this time point using a highly sensitive competitive polymerase chain reaction assay. The increase in mRNA and protein expression was preceded by increased 12-LO pathway activity measured by a RIA for 12-S-HETE. Separate experiments using purified Sprague-Dawley rat islets also showed increased expression of 12-LO mRNA and enzyme activity in response to IL-1 beta. These results demonstrate that IL-1 beta can up-regulate 12-LO expression and activity in rat beta-cells.

Decreased risk of type I diabetes in offspring of mothers who acquire diabetes during adrenarchy

Fathers with type I diabetes transmit diabetes to their offspring 2-3 times more frequently than mothers with type I diabetes. This phenomenon has provoked both genetic and nongenetic hypotheses, but the mechanism remains obscure. We find that mothers who develop diabetes before age 8 transmit diabetes at the same rate as diabetic fathers, and that the sex difference in diabetes transmission is explained by a decreased transmission rate in mothers who acquired diabetes after age 8. We constructed a data base containing 2156 nondiabetic and diabetic offspring of parents with type I diabetes. Families were selected from our main data base, which contains demographic information and diabetes autoantibody test results on > 8000 first-degree relatives of patients with type I diabetes and diabetic probands. Identification of offspring was made through diabetic parents who had participated in our autoantibody screening program at the Joslin Diabetes Center between 1983 and 1990. Questionnaires were sent to all other family members to determine the number of diabetic and nondiabetic offspring in each family. The 20-yr life-table risk of diabetes in offspring of diabetic fathers and mothers is 8.9 +/- 1.0 and 3.4 +/- 0.6%, respectively. For mothers acquiring diabetes before or after age 8, the risk of diabetes in offspring is 13.9 +/- 4.4 and 2.4 +/- 0.6% at 20 yr of age, respectively. Furthermore, we find that duration of diabetes in mothers before pregnancy has no effect on the risk of diabetes in their offspring.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of metabolic progression to type I diabetes in ICA+ relatives of patients with type I diabetes

We intensively studied 5 islet cell-antibody-positive (ICA+) first-degree relatives of type I (insulin-dependent) diabetic patients before overt diabetes. In total, 55 intravenous glucose tolerance tests (IVGTTs) and 83 fasting plasma glucose determinations were made over a maximum 4-yr period before diabetes. The 5 prediabetic relatives (not diabetic when initially studied but subsequently progressed to overt diabetes) as a group showed a progressive rise in fasting glucose (r = 0.58, P less than 0.001, slope = 23.1 mg.dl-1.yr-1) and glucose at 60 min in IVGTT (r = 0.46, P = 0.01, slope = 47.5 mg.dl-1.yr-1) beginning 1.5 yr before diabetes. During the 4.0- to 1.5-yr period before overt diabetes, no change was observed in fasting glucose or glucose at 60 min on IVGTT (fasting glucose: r = 0.21, P = 0.18, slope = 2.1 mg.dl-1.yr-1; 60-min glucose: r = 0.08, P = 0.72, slope = 2.9 mg.dl-1.yr-1). The positive predictive value for a fasting glucose greater than 108 mg/dl to be within 1.5 yr of diabetes was 100% (11 of 11 values). The negative predictive value of a stimulated insulin (1-min + 3-min insulin - 2 X basal insulin) level greater than 24 microU/ml to be greater than 1.5 yr from diabetes was 90% (9 of 10 values) and 100% (10 of 10 values) at greater than 1 yr from overt diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)