Aggravation of diabetes, and incompletely deficient insulin secretion in a case with type 1 diabetes-resistant human leukocyte antigen DRB1*15:02 treated with nivolumab

Anti-programmed cell death-1 (PD-1) antibody therapy induces various adverse effects, especially in the endocrine system. Several cases of acute-onset insulin-dependent diabetes after anti-PD-1 antibody therapy have been reported. Many of these cases have a susceptible human leukocyte antigen (HLA) genotype for type 1 diabetes, possibly suggesting that HLA might be involved in the onset of diabetes with anti-PD-1 therapy. We describe an atypical case of hyperglycemia after anti-PD-1 antibody administration. A 68-year-old Japanese man with pancreatic diabetes and steroid diabetes was given nivolumab three times for chemoresistant adenocarcinoma of the lung. On day 5 after the third infusion of nivolumab, he had hyperglycemia (blood glucose 330 mg/dL and hemoglobin A1c 8.0%) without ketosis and with incompletely deficient insulin secretion. The patient had both type 1 diabetes susceptible (HLA-A*24:02 and -DRB1*09:01) and resistant (HLA-DRB1*15:02) HLA genotypes. These HLA genotypes differ from those previously reported in anti-PD-1 antibody-induced diabetes, and might have influenced the preservation of insulin secretion after nivolumab administration in the present case.

Aldose Reductase Mediates NLRP3 Inflammasome-Initiated Innate Immune Response in Hyperglycemia-Induced Thp1 Monocytes and Male Mice

Despite recent studies that show oxidative stress-generated reactive oxygen species (ROS) regulate NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediated innate immune response in various diabetic complications, the mechanism by which ROS activate innate immune response is not well understood. We have shown previously that aldose reductase (AR), besides reducing glucose, reduces lipid aldehydes and their glutathione conjugates and participates in various oxidative stress-induced inflammatory pathways. To understand the role of AR in ROS-induced innate immune response, we have investigated the mechanism(s) by which AR activates hyperglycemia-induced NLRP3 inflammsome-initiated innate immune response in Thp1 monocytes and in streptozotocin (STZ)-induced diabetic mice. In Thp1 monocytes, inhibition or ablation of AR prevented high-glucose-induced activation of NLRP3 inflammasome and caspase-1 and release of the innate immune cytokines interleukin (IL)-1β and IL-18. AR inhibition in Thp1 cells also prevented the high-glucose-induced generation of ROS, influx of Ca2+, efflux of K+, and activation of Lyn, Syk, and PI3K. Furthermore, the AR inhibitor fidarestat prevented the expression of NLRP inflammasome components in STZ-induced diabetic mouse heart and aorta, and also prevented the release of various cytokines in the serum. Collectively, our data suggest that AR regulates hyperglycemia-induced NLRP3 inflammasome-mediated innate immune response by altering the ROS/Lyn/Syk/PI3K/Ca2+/K+ signals.

The complex interplay among hepatocytes and immune cells at the crossroad between inflammation and cholesterol metabolism in hyperglycemia

An intriguing piece of evidence for the inflammatory story of type 2 diabetes has come to the light. A recent study by Okin and colleagues adds new clues to the interplay between cholesterol metabolism and immunity and how it impacts glucose homeostasis in inflammatory conditions. But some questions are a still unsolved conundrum. Here we suggest to better dissect the regulatory mechanism of Mevalonate pathway and to underpin a new causative link between immunometabolic dysregulation and diabetes.

TNFα contributes to diabetes impaired angiogenesis in fracture healing

Diabetes increases the likelihood of fracture, interferes with fracture healing and impairs angiogenesis. The latter may be significant due to the critical nature of angiogenesis in fracture healing. Although it is known that diabetes interferes with angiogenesis the mechanisms remain poorly defined. We examined fracture healing in normoglycemic and streptozotocin-induced diabetic mice and quantified the degree of angiogenesis with antibodies to three different vascular markers, CD34, CD31 and Factor VIII. The role of diabetes-enhanced inflammation was investigated by treatment of the TNFα-specific inhibitor, pegsunercept starting 10days after induction of fractures. Diabetes decreased both angiogenesis and VEGFA expression by chondrocytes. The reduced angiogenesis and VEGFA expression in diabetic fractures was rescued by specific inhibition of TNF in vivo. In addition, the TNF inhibitor rescued the negative effect of diabetes on endothelial cell proliferation and endothelial cell apoptosis. The effect of TNFα in vitro was enhanced by high glucose and an advanced glycation endproduct to impair microvascular endothelial cell proliferation and tube formation and to stimulate apoptosis. The effect of TNF, high glucose and an AGE was mediated by the transcription factor FOXO1, which increased expression of p21 and caspase-3. These studies indicate that inflammation plays a major role in diabetes-impaired angiogenesis in endochondral bone formation through its effect on microvascular endothelial cells and FOXO1.

Differential Impact of Chronic Hyperglycemia on Humoral Versus Cellular Primary Alloimmunity

Diabetes is prevalent among solid organ transplant recipients and is universal among islet transplant recipients. Whereas diabetes is often considered to result in an immune-compromised state, the impact of chronic hyperglycemia on host alloimmunity is not clear. Potential immune-modifying effects of obesity, autoimmunity, or diabetogenic agents like streptozotocin may confound understanding alloimmunity in experimental models of diabetes. Therefore, we sought to determine the role of chronic hyperglycemia due to insulinopenia on alloimmunity using the nonautoimmune, spontaneously diabetic H-2^b-expressing C57BL/6 Ins2^Akita mice (Akita). Akita mice harbor a mutated Ins2 allele that dominantly suppresses insulin secretion, resulting in lifelong diabetes. We used BALB/c donors (H-2^d) to assess alloimmunization and islet transplantation outcomes in Akita recipients. Surprisingly, chronic hyperglycemia had little effect on primary T-cell reactivity after alloimmunization. Moreover, Akita mice readily rejected islet allografts, and chronic hyperglycemia had no impact on the magnitude or quality of intragraft T-cell responses. In contrast, allospecific IgM and IgG were significantly decreased in Akita mice after alloimmunization. Thus, whereas diabetes influences host immune defense, hyperglycemia itself does not cause generalized alloimmune impairment. Our data suggest that immune compromise in diabetes due to hyperglycemia may not apply to cellular rejection of transplants.

Non-enzymatic glucosylation induced neo-epitopes on human serum albumin: A concentration based study

Hyperglycaemia induced non enzymatic glycation is accelerated in diabetic patients and aggressively involved in diabetes progression. Human serum albumin (HSA) is the most abundant protein in blood circulation. In hyperglycaemia, it undergoes fast glycation and results in the impairment of structure. Our previous study has demonstrated structural alterations in Amadori-albumin modified with different glucose concentrations from physiological to pathophysiological range. Here, we focused on immunological characterization of Amadori-albumin. Immunogenicity of Amadori-albumin was analysed by direct binding and competitive ELISA. Amadori-albumin was found to be highly immunogenic (expect albumin modified with 5mM) and induced high titre antibodies depending upon the extent of modification. Very high titre antibodies were obtained with albumin modified with 75mM glucose as compared to native albumin. Anti-Amadori-albumin-IgG from rabbit sera exhibited increased recognition of Amadori-albumin than native albumin in competitive immunoassay. Alteration induced in albumin after glucosylation has made it highly immunogenic. Induced antibodies were quite specific for respective immunogens but showed cross-reaction with other Amadori/native proteins. It suggests that glucosylation has generated highly immunogenic epitopes on albumin. Formation of high molecular weight immune complex with retarded mobility further supports specificity of anti-Amadori-albumin-IgG towards Amadori-albumin. It may be concluded that due to early glycation, an array of modification occurred in HSA structure. Such gross structural changes might favour polymerization of most of the native epitopes into potent immunogenic neo-epitopes, but some original epitopes were still active and has contributed in the immunogenicity. It could be concluded that induction of anti-Amadori-albumin antibodies may be due to protection of glucose modified albumin from protiolytic breakdown. We assumed that this type of protein modifications might occur in diabetic patients in hyperglycaemic conditions that may be recognised as foreign molecules and can induce autoantibodies. Increased level of anti-Amadori-albumin autoantibodies may be used as a biomarker in disease diagnosis and its progression.

Diabetes propels the risk for cardiovascular disease: sweet monocytes becoming aggressive?

Diabetes strongly predisposes to cardiovascular disease (CVD), the leading cause of mortality in these patients, as well as in the entire population. Hyperglycemia is an important cardiovascular risk factor as shown by the observation that even transient periods of hyperglycemia, despite return to normoglycemia during follow-up, increase the risk for CVD, a phenomenon termed 'hyperglycemic memory'. The molecular mechanisms underlying this phenomenon remain largely unknown. As inflammation plays an important role in the pathogenesis of atherosclerosis, we propose that long-term functional reprogramming of monocytes and macrophages, induced by hyperglycemia, plays an important role in the phenomenon of hyperglycemic memory leading to cardiovascular complications in patients with diabetes. In this review, we discuss recent insights showing that innate immune cells possess the capacity to reprogram their function through epigenetically mediated rewiring of gene transcription, a process termed 'trained immunity'. The long-term reprogramming of monocytes can be induced by microbial as well as metabolic products, and involves a shift in cellular metabolism from oxidative phosphorylation to aerobic glycolysis. We hypothesize that hyperglycemia in diabetes patients induces long-term activation of monocytes and macrophages through similar mechanisms, thereby contributing to plaque development and subsequent macrovascular complications.

Role of Oxidative Stress and Inflammatory Factors in Diabetic Kidney Disease

Diabetic nephropathy (DN) is a serious complication of diabetes mellitus, and its prevalence has been increasing in developed countries. Diabetic nephropathy has become the most common single cause of end-stage renal disease worldwide. Oxidative stress and inflammation factors are hypothesized to play a role in the development of late diabetes complications. Chronic hyperglycemia increases oxidative stress, significantly modifies the structure and function of proteins and lipids, and induces glycoxidation and peroxidation. Therefore, hyperglycemia causes auto-oxidation of glucose, glycation of proteins, and activation of polyol mechanism. Overproduction of intracellular reactive oxygen species contributes to several microvascular and macrovascular complications of DN. On the other hand, reactive oxygen species modulates signaling cascade of immune factors. An increase in reactive oxygen species can increase the production of inflammatory cytokines, and likewise, an increase in inflammatory cytokines can stimulate the production of free radicals. Some studies have shown that kidney inflammation is serious in promoting the development and progression of DN. Inflammatory factors which are activated by the metabolic, biochemical, and hemodynamic derangements are known to exist in the diabetic kidney. This review discusses facts for oxidative stress and inflammatory factors in DN and encompasses the role of immune and inflammatory cells, inflammatory cytokines, and stress oxidative factors.

Modulation of dendritic cell and monocyte subsets in tuberculosis-diabetes co-morbidity upon standard tuberculosis treatment

Type 2 diabetes mellitus (DM) is a major risk factor for the development of active pulmonary tuberculosis (PTB), with development of DM pandemic in countries where tuberculosis (TB) is also endemic. However, the effect of anti-TB treatment on the changes in dentritic cell (DC) and monocyte subset phenotype in TB-DM co-morbidity is not well understood. In this study, we characterized the frequency of DC and monocyte subsets in individuals with PTB with (PTB-DM) or without coincident diabetes mellitus (PTB-NDM) before, during and after completion of anti-TB treatment. PTB-DM is characterized by diminished frequencies of plasmacytoid and myeloid DCs and classical and intermediate monocytes at baseline and 2 months of anti-TB treatment but not following 6 months of treatment completion in comparison to PTB-NDM. DC and monocyte subsets exhibit significant but borderline correlation with fasting blood glucose and glycated hemoglobin levels. Finally, while minor changes in the DC and monocyte compartment were observed at 2 months of treatment, significantly increased frequencies of plasmacytoid and myeloid DCs and classical and intermediate monocytes were observed at the successful completion of anti-TB treatment. Our data show that coincident diabetes alters the frequencies of innate subset distribution of DC and monocytes in TB-DM co-morbidity and suggests that most of these changes are reversible following anti-TB therapy.

Toll-like receptors 2 and 4 mediate hyperglycemia induced macrovascular aortic endothelial cell inflammation and perturbation of the endothelial glycocalyx

OBJECTIVES

Hyperglycemia-induced inflammation is central to the vascular complications in diabetes. Toll-like receptors (TLRs) are key players in regulating inflammatory responses. There are sparse data on the role of TLR2 and TLR4 in regulating human macrovascular aortic endothelial cells (HMAECs) inflammation and glycocalyx dysfunction under hyperglycemia. We examined the role of TLR2/4 in the above dysfunctions in HMAEC under high glucose (HG) conditions.

METHODS

HMAECs were treated with high or normal glucose and TLR-2, TLR-4, MyD88, IRF3, TRIF, nuclear NF-κB p65, IL-8, IL-1β, TNF-α, MCP-1, ICAM-1, sVCAM-1, monocyte adhesion to HMAECs, heparan sulfate and hyaluronic acid were measured.

RESULTS

HG upregulated TLR2 and TLR4 mRNA and protein and increased both MyD88 and non-MyD88 pathways, NF-κB p65, inflammatory biomediators, and monocyte adhesion to HMAECs. Heparan sulfate protein expression was reduced and hyaluronic acid secretion was increased on HG exposure. Inhibition of TLR2 and TLR4 signaling by inhibitory peptides and knockdown of TLR-2 and TLR-4 gene expression by siRNA attenuated HG induced inflammation, leukocyte adhesion and glycocalyx dysfunction. An increase in ROS paralleled the increase in TLR-2/4 and antioxidants treatment reduced TLR-2/4 expression and downstream inflammatory biomediators.

CONCLUSION

Thus hyperglycemia induces HMAEC inflammation and glycocalyx dysfunction through TLR-2/4 pathway activation via increased ROS.

Nesfatin-1 improves oxidative skin injury in normoglycemic or hyperglycemic rats

Hyperglycemia is one of the major causes of suppressed angiogenesis and impaired wound healing leading to chronic wounds. Nesfatin-1 a novel peptide was reported to have antioxidant and anti-apoptotic properties. This study is aimed to investigate the potential healing-promoting effects of nesfatin-1 in non-diabetic or diabetic rats with surgical wounds. In male Sprague-Dawley rats, hyperglycemia was induced by intraperitoneal (ip) injection of streptozotocin (55 mg/kg). Under anesthesia, dorsum skin tissues of normoglycemic (n=16) and hyperglycemic rats were excised (2 × 2 cm, full-thickness), while control rats (n=16) had neither hyperglycemia nor wounds. Half of the rats in each group were treated ip with saline, while the others were treated with nesfatin-1 (2 μg/kg/day) for 3 days until they were decapitated. Plasma interleukin-1-beta (IL-1β), transforming growth factor-beta (TGF-β-1), IL-6 levels, and dermal tissue malondialdehyde (MDA), glutathione (GSH) levels, myeloperoxidase (MPO) and caspase-3 activity were measured. For histological examination, paraffin sections were stained with hematoxylin-eosin or Masson's trichrome and immunohistochemistry for vascular endothelial growth factor (VEGF) was applied. ANOVA and Student's t-tests were used for statistical analysis. Compared to control rats, skin MPO activity, MDA and caspase-3 levels were increased similarly in saline-treated normo- and hyperglycemic rats. Nesfatin-1 depressed MDA, caspase-3, MPO activity and IL-1β with concomitant elevations in dermal GSH and plasma TGF-β-1 levels. Histopathological examination revealed regeneration of epidermis, regular arrangement of collagen fibers in the dermis and a decrease in VEGF immunoreactivity in the epidermal keratinocytes of nesfatin-1-treated groups. Nesfatin-1 improved surgical wound healing in both normo- and hyperglycemic rats via the suppression of neutrophil recruitment, apoptosis and VEGF activation.

SNP-SNP Interaction between TLR4 and MyD88 in Susceptibility to Coronary Artery Disease in the Chinese Han Population

The toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88)-dependent signaling pathway plays a role in the initiation and progression of coronary artery disease (CAD). We investigated SNP-SNP interactions between the TLR4 and MyD88 genes in CAD susceptibility and assessed whether the effects of such interactions were modified by confounding risk factors (hyperglycemia, hyperlipidemia and Helicobacter pylori (H. pylori) infection). Participants with CAD (n = 424) and controls (n = 424) without CAD were enrolled. Polymerase chain restriction-restriction fragment length polymorphism was performed on genomic DNA to detect polymorphisms in TLR4 (rs10116253, rs10983755, and rs11536889) and MyD88 (rs7744). H. pylori infections were evaluated by enzyme-linked immunosorbent assays, and the cardiovascular risk factors for each subject were evaluated clinically. The significant interaction between TLR4 rs11536889 and MyD88 rs7744 was associated with an increased CAD risk (p value for interaction = 0.024). In conditions of hyperglycemia, the interaction effect was strengthened between TLR4 rs11536889 and MyD88 rs7744 (p value for interaction = 0.004). In hyperlipidemic participants, the interaction strength was also enhanced for TLR4 rs11536889 and MyD88 rs7744 (p value for interaction = 0.006). Thus, the novel interaction between TLR4 rs11536889 and MyD88 rs7744 was related with an increased risk of CAD, that could be strengthened by the presence of hyperglycemia or hyperlipidemia.

Lack of p47(phox) in Akita Diabetic Mice Is Associated with Interstitial Pneumonia, Fibrosis, and Oral Inflammation

Excess reactive oxygen species production is central to the development of diabetic complications. The contribution of leukocyte reactive oxygen species produced by the NADPH oxidase to altered inflammatory responses associated with uncontrolled hyperglycemia is poorly understood. To get insight into the role of phagocytic superoxide in the onset of diabetic complications, we used a model of periodontitis in mice with chronic hyperglycemia and lack of leukocyte p47(phox) (Akita/Ncf1) bred from C57BL/6-Ins2(Akita)/J (Akita) and neutrophil cytosolic factor 1 knockout (Ncf1) mice. Akita/Nfc1 mice showed progressive cachexia starting at early age and increased mortality by six months. Their lungs developed infiltrative interstitial lesions that obliterated air spaces as early as 12 weeks when fungal colonization of lungs also was observed. Neutrophils of Akita/Ncf1 mice had normal degranulation and phagocytic efficiency when compared with wild-type mice. Although Akita/Ncf1 mice had increased prevalence of oral infections and more severe periodontitis compared with wild-type mice, bone loss was only marginally higher compared with Akita and Ncf1 null mice. Altogether these results indicate that lack of leukocyte superoxide production in mice with chronic hyperglycemia results in interstitial pneumonia and increased susceptibility to infections.

SENP1-mediated NEMO deSUMOylation in adipocytes limits inflammatory responses and type-1 diabetes progression

Adipocyte dysfunction correlates with the development of diabetes. Here we show that mice with a adipocyte-specific deletion of the SUMO-specific protease SENP1 gene develop symptoms of type-1 diabetes mellitus (T1DM), including hyperglycaemia and glucose intolerance with mild insulin resistance. Peri-pancreatic adipocytes from SENP1-deficient mice exhibit heightened NF-κB activity and production of proinflammatory cytokines, which induce CCL5 expression in adjacent pancreatic islets and direct cytotoxic effects on pancreatic islets. Mechanistic studies show that SENP1 deletion in adipocytes enhances SUMOylation of the NF-κB essential molecule, NEMO, at lysine 277/309, leading to increased NF-κB activity, cytokine production and pancreatic inflammation. We further show that NF-κB inhibitors could inhibit pre-diabetic cytokine production, β-cell damages and ameliorate the T1DM phenotype in SENP1-deficient mice. Feeding a high-fat diet augments both type-1 and type-2 diabetes phenotypes in SENP1-deficient mice, consistent with the effects on adipocyte-derived NF-κB and cytokine signalling. Our study reveals previously unrecognized mechanism regulating the onset and progression of T1DM associated with adipocyte dysfunction.

Markers of autophagy are adapted to hyperglycaemia in skeletal muscle in type 2 diabetes

AIMS/HYPOTHESIS

Autophagy is a catabolic process that maintains cellular homeostasis by degradation of protein aggregates and selective removal of damaged organelles, e.g. mitochondria (mitophagy). Insulin resistance in skeletal muscle has been linked to mitochondrial dysfunction and altered protein metabolism. Here, we investigated whether abnormalities in autophagy are present in human muscle in obesity and type 2 diabetes.

METHODS

Using a case-control design, skeletal muscle biopsies obtained in the basal and insulin-stimulated states from patients with type 2 diabetes during both euglycaemia and hyperglycaemia, and from glucose-tolerant lean and obese individuals during euglycaemia, were used for analysis of mRNA levels, protein abundance and phosphorylation of autophagy-related proteins.

RESULTS

Muscle transcript levels of autophagy-related genes (ULK1, BECN1, PIK3C3, ATG5, ATG7, ATG12, GABARAPL1, MAP1LC3B, SQSTM1, TP53INP2 and FOXO3A [also known as FOXO3]), including some specific for mitophagy (BNIP3, BNIP3L and MUL1), and protein abundance of autophagy-related gene (ATG)7 and Bcl-2/adenovirus E1B 19-kDa-interacting protein 3 (BNIP3), as well as content and phosphorylation of forkhead box O3A (FOXO3A) were similar among the groups. Insulin reduced lipidation of microtubule-associated protein light chain 3 (LC3)B-I to LC3B-II, a marker of autophagosome formation, with no effect on p62/sequestosome 1 (SQSTM1) content in muscle of lean and obese individuals. In diabetic patients, insulin action on LC3B was absent and p62/SQSTM1 content increased when studied under euglycaemia, whereas the responses of LC3B and p62/SQSTM1 to insulin were normalised during hyperglycaemia.

CONCLUSIONS/INTERPRETATION

Our results demonstrate that the levels of autophagy-related genes and proteins in muscle are normal in obesity and type 2 diabetes. This suggests that muscle autophagy in type 2 diabetes has adapted to hyperglycaemia, which may contribute to preserve muscle mass.

Renal tubular damage may contribute more to acute hyperglycemia induced kidney injury in non-diabetic conscious rats

AIMS

Growing evidences suggest that acute hyperglycemia is strongly related to kidney injury. Our study aimed to investigate the effects of acute hyperglycemia on kidney glomerular and tubular impairment in non-diabetic conscious rats.

METHODS

Non-diabetic conscious rats were randomly subjected to 6h of saline (control group) or high glucose (acute hyperglycemia group) infusion. Blood glucose was maintained at 16.0-18.0 mmol/L in acute hyperglycemia group. Renal structure and function alterations, systemic/renal inflammation and oxidative stress markers were assessed, and apoptosis markers of renal inherent cells were evaluated.

RESULTS

Acute hyperglycemia caused significant injury to structure of glomerular filtration barrier, tubular epithelial cells and peritubular vascular endothelial cells. It increased urinary microalbumin (68.01 ± 27.09 μg/24h vs 33.81 ± 13.81 μg/24h , P=0.014), β2-microglobulin, Cystatin C, urinary and serous neutrophil gelatinase-associated lipocalin levels (P < 0.05). Acute hyperglycemia decreased megalin and cubilin expression, activated systemic and renal oxidative stress as well as inflammation and promoted renal inherent cell apoptosis.

CONCLUSIONS

Acute hyperglycemia causes significant injury to kidney function and structure. Compared with damages of glomerular filtration barrier, renal tubular injury may contribute more to acute hyperglycemia induced proteinuria. Activation of inflammation especially renal inflammation, oxidative stress and enhanced apoptosis may be the underlying mechanisms.

11-Keto-β-Boswellic Acids Prevent Development of Autoimmune Reactions, Insulitis and Reduce Hyperglycemia During Induction of Multiple Low-Dose Streptozotocin (MLD-STZ) Diabetes in Mice

The aim of the work was to study whether or not 11-keto-β-boswellic acids prevent induction of autoimmune reactions, insulitis, and hyperglycemia in the model of multiple low-dose streptozotocin (MLD-STZ) diabetes. Using male mice (n = 6) diabetes was induced by daily i.p. injections of 40 mg/kg STZ for 5 days. In a second series together with STZ, daily i. p. injections of 11-keto-β-boswellic acid (KBA) and O-acetyl-11-keto-β-boswellic acid (AKBA) (7.5 and 15.0 mg/kg) were applied for 10 days. Thereafter, pro-and anti-inflammatory cytokines in the blood, histochemistry of pancreatic islets, and blood glucose levels were assayed. Five days after the last injection of STZ, a significant burst of pro-and anti-inflammatory cytokines in the blood, infiltration of lymphocytes (CD3) into pancreatic islets, and appearance of peri-insular apoptotic cells were observed. Plasma glucose increased significantly (124.4 ± 6.65 vs. 240.2 ± 27.36 mg/dl, p <0.05). Simultaneous treatment with KBA and AKBA significantly reduced pro-and anti-inflammatory cytokines (IFN-γ p < 0.01, p < 0.01; IL-1A p < 0.001, p < 0.001; IL-1B p < 0.001, p < 0.001; IL-2 p < 0.001, p < 0.001; IL-6 p < 0.01, p < 0.001; TNF-α p < 0.05, p < 0.001; IL-4 p < 0.01, p < 0.001; IL-10 p < 0.001, p < 0.001) in the blood. No infiltration of lymphocytes into pancreatic islets and appearance of peri-insular cells were detected. Moreover, KBA and AKBA reduced STZ-mediated increase of blood glucose on day 10 to 163.25 ± 16.6 (p < 0.05) and 187.6 ± 19.5 mg/dl (p < 0.05), respectively. In the model of MLD-STZ induced diabetes KBA and AKBA prevent cytokine burst, development of insulitis and reduce increase of blood glucose through "silencing" a forced-up immune reaction.

Pancreatic β-cell dysfunction in polycystic ovary syndrome: role of hyperglycemia-induced nuclear factor-κB activation and systemic inflammation

In polycystic ovary syndrome (PCOS), oxidative stress is implicated in the development of β-cell dysfunction. However, the role of mononuclear cell (MNC)-derived inflammation in this process is unclear. We determined the relationship between β-cell function and MNC-derived nuclear factor-κB (NF-κB) activation and tumor necrosis factor-α (TNF-α) secretion in response to a 2-h 75-g oral glucose tolerance test (OGTT) in normoglycemic women with PCOS (15 lean, 15 obese) and controls (16 lean, 14 obese). First- and second-phase β-cell function was calculated as glucose-stimulated insulin secretion (insulin/glucose area under the curve for 0-30 and 60-120 min, respectively) × insulin sensitivity (Matsuda Index derived from the OGTT). Glucose-stimulated NF-κB activation and TNF-α secretion from MNC, and fasting plasma thiobarbituric acid-reactive substances (TBARS) and high-sensitivity C-reactive protein (hs-CRP) were also assessed. In obese women with PCOS, first- and second-phase β-cell function was lower compared with lean and obese controls. Compared with lean controls, women with PCOS had greater change from baseline in NF-κB activation and TNF-α secretion, and higher plasma TBARS. β-Cell function was inversely related to NF-κB activation (1st and 2nd) and TNF-α secretion (1st), and plasma TBARS and hs-CRP (1st and 2nd). First- and second-phase β-cell function also remained independently linked to NF-κB activation after adjustment for body fat percentage and TBARS. In conclusion, β-cell dysfunction in PCOS is linked to hyperglycemia-induced NF-κB activation from MNC and systemic inflammation. These data suggest that in PCOS, inflammation may play a role in impairing insulin secretion before the development of overt hyperglycemia.

Experimental hyperglycemia induces an increase of monocyte and T-lymphocyte content in adipose tissue of healthy obese women

Background/Objectives

Hyperglycemia represents one of possible mediators for activation of immune system and may contribute to worsening of inflammatory state associated with obesity. The aim of our study was to investigate the effect of a short-term hyperglycemia (HG) on the phenotype and relative content of immune cells in circulation and subcutaneous abdominal adipose tissue (SAAT) in obese women without metabolic complications.

Subjects/Methods

Three hour HG clamp with infusion of octreotide and control investigations with infusion of octreotide or saline were performed in three groups of obese women (Group1: HG, Group 2: Octreotide, Group 3: Saline, n=10 per group). Before and at the end of the interventions, samples of SAAT and blood were obtained. The relative content of immune cells in blood and SAAT was determined by flow cytometry. Gene expression analysis of immunity-related markers in SAAT was performed by quantitative real-time PCR.

Results

In blood, no changes in analysed immune cell population were observed in response to HG. In SAAT, HG induced an increase in the content of CD206 negative monocytes/macrophages (p<0.05) and T lymphocytes (both T helper and T cytotoxic lymphocytes, p<0.01). Further, HG promoted an increase of mRNA levels of immune response markers (CCL2, TLR4, TNFα) and lymphocyte markers (CD3g, CD4, CD8a, TBX21, GATA3, FoxP3) in SAAT (p<0.05 and 0.01). Under both control infusions, none of these changes were observed.

Conclusions

Acute HG significantly increased the content of monocytes and lymphocytes in SAAT of healthy obese women. This result suggests that the short-term HG can modulate an immune status of AT in obese subjects.

Viral infection of engrafted human islets leads to diabetes

Type 1 diabetes (T1D) is characterized by the destruction of the insulin-producing β-cells of pancreatic islets. Genetic and environmental factors both contribute to T1D development. Viral infection with enteroviruses is a suspected trigger for T1D, but a causal role remains unproven and controversial. Studies in animals are problematic because of species-specific differences in host cell susceptibility and immune responses to candidate viral pathogens such as coxsackievirus B (CVB). In order to resolve the controversial role of viruses in human T1D, we developed a viral infection model in immunodeficient mice bearing human islet grafts. Hyperglycemia was induced in mice by specific ablation of native β-cells. Human islets, which are naturally susceptible to CVB infection, were transplanted to restore normoglycemia. Transplanted mice were infected with CVB4 and monitored for hyperglycemia. Forty-seven percent of CVB4-infected mice developed hyperglycemia. Human islet grafts from infected mice contained viral RNA, expressed viral protein, and had reduced insulin levels compared with grafts from uninfected mice. Human-specific gene expression profiles in grafts from infected mice revealed the induction of multiple interferon-stimulated genes. Thus, human islets can become severely dysfunctional with diminished insulin production after CVB infection of β-cells, resulting in diabetes.

Phytochemical profile, antioxidative and anti-inflammatory potentials of Gynura bicolor DC

BACKGROUND

The phytochemical composition of aqueous and ethanol extracts from Gynura bicolor DC., a vegetable, was determined. Human umbilical vein endothelial (HUVE) cells were used to examine the antioxidative and anti-inflammatory potentials of these extracts at 1, 2 or 4% (v/v) against high-glucose-induced injury.

RESULTS

Both aqueous and ethanol extracts contained phenolic acids, flavonoids, carotenoids and anthocyanins in the ranges 1428-1569, 1934-2175, 921-1007 and 2135-2407 mg per 100 g dry weight respectively. Both extracts were rich in quercetin, lutein, malvidin and pelargonidin. Addition of these extracts at test doses decreased reactive oxygen species formation, preserved glutathione content and retained glutathione peroxide and catalase activities in high-glucose-treated HUVE cells (P < 0.05). Treatments with these extracts at 2 and 4% lowered interleukin-6, tumor necrosis factor-alpha and prostaglandin E2 production and reduced cyclooxygenase-2 activity (P < 0.05).

CONCLUSION

These findings suggest that this vegetable could be considered as a functional food and might provide antioxidative and anti-inflammatory protection.

The influence of maternal islet beta-cell autoantibodies in conjunction with gestational hyperglycemia on neonatal outcomes

Objective

To determine the predictive value of the presence of maternal islet beta-cell autoantibodies with respect to neonatal outcomes.

Methods

A total of 311 pregnant women with abnormal 75 g oral glucose tolerance test (OGTT) results were enrolled in this study. Maternal glutamic acid decarboxylase autoantibodies (GADA), islet cell autoantibodies (ICA) and insulin autoantibodies (IAA) were tested in fasting blood both on the day following the routine OGTT and before delivery. The birth weight, Apgar score, blood glucose and outcomes of each neonate were later evaluated and recorded.

Results

1. In this study, 33.9% of the pregnant women with gestational hyperglycemia had detectable levels of one or more types of anti-islet cell antibodies in the third trimester. The proportion of women who produced GADA and/or ICA was significantly higher in the group of women with gestational hyperglycemia than in the control group (P<0.05). The groups similarly differed in the proportion of women who tested positive for any anti-islet cell antibody (P<0.05). 2. Of the patients in our study, those who produced GADA exhibited an increase in uterine and umbilical arterial pulsatility indexes (PIs) during the third trimesters compared with the control group (P˂0.05). Additionally, an increased frequency of fetal growth restriction (FGR) was observed in the infants of women who produced IAA during pregnancy compared with those without autoantibodies (P˂0.05). 3. The rate of newborn admission to the neonatal intensive care unit (NICU) was significantly associated with the presence of maternal ICA during the third trimester (OR, 6.36; 95% CI, 1.22–33.26). 4. The incidence of neonatal asphyxia was associated with the presence of maternal GADA in both the second (OR, 10.44; 95% CI, 1.46–74.92) and the third (OR, 8.33; 95% CI, 1.45–47.82) trimesters.

Conclusion

Approximately one-third of the women with gestational hyperglycemia produced anti-islet cell antibodies. The incidence of FGR was higher in women with gestational hyperglycemia who produced IAA than in those without autoantibodies. Maternal ICA production in the third trimester was a risk factor for the subsequent admission of newborns to the NICU. Furthermore, the presence of maternal GADA placed the neonate at increased risk for asphyxia.

Hyperhomocysteinemia potentiates hyperglycemia-induced inflammatory monocyte differentiation and atherosclerosis

Hyperhomocysteinemia (HHcy) is associated with increased diabetic cardiovascular diseases. However, the role of HHcy in atherogenesis associated with hyperglycemia (HG) remains unknown. To examine the role and mechanisms by which HHcy accelerates HG-induced atherosclerosis, we established an atherosclerosis-susceptible HHcy and HG mouse model. HHcy was established in mice deficient in cystathionine β-synthase (Cbs) in which the homocysteine (Hcy) level could be lowered by inducing transgenic human CBS (Tg-hCBS) using Zn supplementation. HG was induced by streptozotocin injection. Atherosclerosis was induced by crossing Tg-hCBS Cbs mice with apolipoprotein E-deficient (ApoE(-/-)) mice and feeding them a high-fat diet for 2 weeks. We demonstrated that HHcy and HG accelerated atherosclerosis and increased lesion monocytes (MCs) and macrophages (MØs) and further increased inflammatory MC and MØ levels in peripheral tissues. Furthermore, Hcy-lowering reversed circulating mononuclear cells, MC, and inflammatory MC and MC-derived MØ levels. In addition, inflammatory MC correlated positively with plasma Hcy levels and negatively with plasma s-adenosylmethionine-to-s-adenosylhomocysteine ratios. Finally, l-Hcy and d-glucose promoted inflammatory MC differentiation in primary mouse splenocytes, which was reversed by adenoviral DNA methyltransferase-1. HHcy and HG, individually and synergistically, accelerated atherosclerosis and inflammatory MC and MØ differentiation, at least in part, via DNA hypomethylation.

Regulation of cardiac β3-adrenergic receptors in hyperglycemia

Beta-adrenoceptors (β-AR), members of the G protein-coupled receptors play important roles in the regulation of heart function. A positive inotropic action of catecholamines is mediated through their interaction with β-AR, located on the sarcolemma, while they can also mediate some deleterious effects, such as cardiac arrhythmias or myocardial apoptosis. The well-known β-AR-associated signaling in heart is composed of a coupled mechanism among both β1- and β2-AR and stimulatory G protein (G(s)). This coupled mechanism further leads to the activation of adenylyl cyclase and thereby increases in intracellular cAMP level. However, recent studies have emphasized the contribution of constitutive β3-AR coupling to G(i) proteins, thereby initiating additional signal transduction pathways, particularly under physiopathological conditions. Diabetic cardiomyopathy, as a distinct entity is recognized due to its diminished responsiveness to β1-AR agonist stimulation in the heart from diabetic rats with no important changes in the responses mediated with β2-AR. Furthermore, an upregulation of β3-AR has been shown in diabetic rat heart with a strong negative inotropic effect on left ventricular function. Experimental data provide evidences that the mechanisms for the negative inotropic effect with β3-AR activation appear to involve a pertussis toxin (PTX)-sensitive G protein and the activation of a nitric oxide synthase pathway. On the other hand, β-blockers demonstrate marked beneficial effects in heart dysfunction with scavenging free radicals and/or acting as an antioxidant with both sex- and dose-dependent manner. However, further investigations are needed to clarify the roles of both altered expression and/or responsiveness of β-AR and the benefits with β-blocker treatment in diabetes. This review discusses the role of β-AR activation, particularly β3-AR in cardiac pathological remodeling under hyperglycemia.

Defects in the acquisition of tumor-killing capability of CD8+ cytotoxic T cells in streptozotocin-induced diabetic mice

Emerging evidences have shown that diabetes mellitus not only raises risk but also heightens mortality rate of cancer. It is not clear, however, whether antitumor CD8⁺ cytotoxic T lymphocyte (CTL) response is down-modulated in diabetic hosts. We investigated the impact of hyperglycemia on CTLs' acquisition of tumor-killing capability by utilizing streptozotocin-induced diabetic (STZ-diabetic) mice. Murine diabetes was induced by intraperitoneal injection of STZ (200 mg/kg) in C57BL/6 mice, 2C-T cell receptor (TCR) transgenic and P14-TCR transgenic mice. The study found that, despite harboring intact proliferative capacity measured with CFSE labeling and MTT assay, STZ-diabetic CD8⁺ CTLs displayed impaired effector functions. After stimulation, STZ-diabetic CD8⁺ CTLs produced less perforin and TNFα assessed by intracellular staining, as well as expressed less CD103 protein. Furthermore, adoptive transfer of STZ-diabetic P14 CD8⁺ effector cells showed an insufficient recruitment to the B16.gp33 melanoma and inadequate production of perforin, granzyme B and TNFα determined by immunohistochemistry in the tumor milieu. As a result, STZ-diabetic CD8⁺ effector cells were neither able to eliminate tumor nor to improve survival of tumor-bearing mice. Taken together, our data suggest that CD8⁺ CTLs are crippled to infiltrate into tumors and thus fail to acquire tumor-killing capability in STZ-diabetic hosts.