Impaired immune responses in streptozotocin-induced type I diabetes in mice. Involvement of high glucose

Impact of Hyperglycemia on Complication and Mortality after Transarterial Chemoembolization for Hepatocellular Carcinoma

BACKGRUOUND

Current guidelines regarding periprocedural glycemic control to prevent complications after nonsurgical invasive procedures are insufficient. Transarterial chemoembolization (TACE) is a widely used treatment for unresectable hepatocellular carcinoma. We aimed to investigate the association between diabetes mellitus (DM) per se and the degree of hyperglycemia with postprocedural complications after TACE.

METHODS

A total of 22,159 TACE procedures performed at Seoul National University Hospital from 2005 to 2018 were retrospectively analyzed. The associations between DM, preprocedural glycosylated hemoglobin (HbA1c), and periprocedural average glucose with postprocedural adverse outcomes were evaluated. The primary outcome was occurrence of postprocedural bacteremia. Secondary outcomes were acute kidney injury (AKI), delayed discharge and death within 14 days. Periprocedural glucose was averaged over 3 days: the day of, before, and after the TACE procedures. Propensity score matching was applied for procedures between patients with or without DM.

RESULTS

Periprocedural average glucose was significantly associated with bacteremia (adjusted odds ratio per 50 mg/dL of glucose, 1.233; 95% confidence interval, 1.071 to 1.420; P=0.004), AKI, delayed discharge, and death within 14 days. DM per se was only associated with bacteremia and AKI. Preprocedural HbA1c was associated with delayed discharge. Average glucose levels above 202 and 181 mg/dL were associated with a significantly higher risk of bacteremia and AKI, respectively, than glucose levels of 126 mg/dL or lower.

CONCLUSION

Periprocedural average glucose, but not HbA1c, was associated with adverse outcomes after TACE, which is a nonsurgical invasive procedure. This suggests the importance of periprocedural glycemic control to reduce postprocedural complications.

Association between a high triglyceride-glucose index and chronic kidney disease in adult patients with latent autoimmune diabetes

BACKGROUND

Insulin resistance (IR) is one of the risk factors for chronic kidney disease (CKD) and diabetes. The triglyceride-glucose (TyG) index is considered a reliable alternative marker of IR. We investigated the correlation between the TyG index and the severity of CKD in patients with latent autoimmune diabetes in adults (LADA).

METHODS

This cross-sectional study included 288 patients with LADA in the department of endocrinology at our hospital between January 2018 and January 2022. The TyG index was calculated as Ln [TG (mg/dl) × fasting blood glucose (FBG) (mg/dl) / 2]. All individuals were divided into either a LADA + CKD group or a LADA + non-CKD group according to the presence or absence of CKD. A correlation analysis, logistic regression analysis and receiver operating characteristics curve analysis were performed.

RESULTS

A total of 130 (45.1%) participants were identified as having CKD. Compared with the non-CKD group, the CKD group had a longer disease duration and a higher proportion of smokers; patients were more likely to have hypertension and higher serum creatinine, triglyceride, cholesterol, low-density lipoprotein cholesterol, FBG, uric acid estimated glomerular filtration rates (eGFR) and TyG levels as well as lower high-density lipoprotein cholesterol levels (all P < 0.05). The positive relationship between the TyG index and the urinary albumin/creatinine ratio was significant (r = 0.249, P = 0.010). There was also a significant correlation between the TyG index and the eGFR (r = - 0.211, P = 0.034) after adjusting for confounding factors. The area-under-the-curve value of the TyG index was 0.708 (95% confidence interval: 0.61-0.81, P < 0.001).

CONCLUSIONS

The TyG index is significantly associated with the severity of CKD in patients with LADA. This conclusion supports the clinical application of the TyG index for the assessment of kidney disease in patients with LADA.

A2BAR Antagonism Decreases the Glomerular Expression and Secretion of Chemoattractants for Monocytes and the Pro-Fibrotic M2 Macrophages Polarization during Diabetic Nephropathy

Some chemoattractants and leukocytes such as M1 and M2 macrophages are known to be involved in the development of glomerulosclerosis during diabetic nephropathy (DN). In the course of diabetes, an altered and defective cellular metabolism leads to the increase in adenosine levels, and thus to changes in the polarity (M1/M2) of macrophages. MRS1754, a selective antagonist of the A2B adenosine receptor (A2BAR), attenuated glomerulosclerosis and decreased macrophage-myofibroblast transition in DN rats. Therefore, we aimed to investigate the effect of MRS1754 on the glomerular expression/secretion of chemoattractants, the intraglomerular infiltration of leukocytes, and macrophage polarity in DN rats. Kidneys/glomeruli of non-diabetic, DN, and MRS1754-treated DN rats were processed for transcriptomic analysis, immunohistopathology, ELISA, and in vitro macrophage migration assays. The transcriptomic analysis identified an upregulation of transcripts and pathways related to the immune system in the glomeruli of DN rats, which was attenuated using MRS1754. The antagonism of the A2BAR decreased glomerular expression/secretion of chemoattractants (CCL2, CCL3, CCL6, and CCL21), the infiltration of macrophages, and their polarization to M2 in DN rats. The in vitro macrophages migration induced by conditioned-medium of DN glomeruli was significantly decreased using neutralizing antibodies against CCL2, CCL3, and CCL21. We concluded that the pharmacological blockade of the A2BAR decreases the transcriptional expression of genes/pathways related to the immune response, protein expression/secretion of chemoattractants, as well as the infiltration of macrophages and their polarization toward the M2 phenotype in the glomeruli of DN rats, suggesting a new mechanism implicated in the antifibrotic effect of MRS1754.

The impact of zinc on the molecular signaling pathways in the diabetes disease

Since there's been an upsurge in people with diabetes or pre-diabetes conditions, many studies have been conducted to evaluate approaches for reducing the complications of diabetes. One of the most common therapeutic elements suggested for this purpose is zinc (Zn). Zn has long been shown to positively improve complications of both type 1 and type 2 diabetes. This review aims to provide comprehensive information about the influence of Zn on the various signaling pathways in multiple tissues with diabetic conditions, with great attention to the treatment period and effective dose of Zn.

TRIB3 reduces CD8+ T cell infiltration and induces immune evasion by repressing the STAT1-CXCL10 axis in colorectal cancer

[Figure: see text].

Strategies for extended lifetime of implantable intraperitoneal insulin catheters

Implantable insulin infusion systems using the intra-peritoneal route have dramatically changed the management of diabetes paving the way toward the realization of the potential "holy grail" of a fully implantable artificial pancreas. However, the wear duration of delivery catheters is compromised by the foreign body-mediated immune response. Both occlusion material present at the distal catheter tip end and fibrotic encapsulation surrounding the catheters influence the controlled and precise delivery of insulin, which eventually leads to the need for surgical intervention. The novel part of the current work is the investigation of the roles of implant physical properties (catheter size and tip configuration), as well as local inflammation control (through utilization of an anti-inflammatory agent) on the host fibrotic response using a previously developed animal model. The cellular and molecular response, the medication delivery efficacy as well as the ability to flush the catheters were examined and further compared among the different mitigation strategies. Reduction in catheter size as well as tuning the tip configuration from a cone shape to a round shape showed delayed host recognition and delayed propagation of the fibrotic response. However, the round shaped tips had an increased occurrence of lumen occlusion as a result of flow change. It became apparent that changing the physical properties of the catheters was not a long-term solution to catheter obstructions caused by the foreign body reaction. In comparison, control of the local inflammatory response through the use of an anti-inflammatory agent demonstrated a promising strategy for maintenance of catheter functionality without any type of obstructions. These finding will have a large impact toward the development of long-term use catheters for continuous intraperitoneal insulin infusion.

Endangered Lymphocytes: The Effects of Alloxan and Streptozotocin on Immune Cells in Type 1 Induced Diabetes

Alloxan (ALX) and streptozotocin (STZ) are extensively used to induce type 1 diabetes (T1D) in animal models. This study is aimed at evaluating the differences in immune parameters caused by ALX and STZ. T1D was induced either with ALX or with STZ, and the animals were followed for up to 180 days. Both ALX and STZ induced a decrease in the total number of circulating leukocytes and lymphocytes, with an increase in granulocytes when compared to control mice (CT). STZ-treated mice also exhibited an increase in neutrophils and a reduction in the lymphocyte percentage in the bone marrow. In addition, while the STZ-treated group showed a decrease in total CD3+, CD4-CD8+, and CD4+CD8+ T lymphocytes in the thymus and CD19+ B lymphocytes in the pancreas and spleen, the ALX group showed an increase in CD4-CD8+ and CD19+ only in the thymus. Basal levels of splenic interleukin- (IL-) 1β and pancreatic IL-6 in the STZ group were decreased. Both diabetic groups showed atrophy of the thymic medulla and degeneration of pancreatic islets of Langerhans composed of inflammatory infiltration and hyperemia with vasodilation. ALX-treated mice showed a decrease in reticuloendothelial cells, enhanced lymphocyte/thymocyte cell death, and increased number of Hassall's corpuscles. Reduced in vitro activation of splenic lymphocytes was found in the STZ-treated group. Furthermore, mice immunized with ovalbumin (OVA) showed a more intense antigen-specific paw edema response in the STZ-treated group, while production of anti-OVA IgG1 antibodies was similar in both groups. Thereby, important changes in immune cell parameters in vivo and in vitro were found at an early stage of T1D in the STZ-treated group, whereas alterations in the ALX-treated group were mostly found in the chronic phase of T1D, including increased mortality rates. These findings suggest that the effects of ALX and STZ influenced, at different times, lymphoid organs and their cell populations.

Altered Renal Pathology in an Autoimmune Disease Mouse Model After Induction of Diabetes Mellitus

Diabetes mellitus (DM) is a predisposing factor for renal disorder progression and is referred to as diabetic kidney disease (DKD). However, there are no reports of DKD with an underlying autoimmune disorder. In this study, we compared the pathophysiological changes caused by DM induction after streptozotocin (STZ) injection in comparison with that in a control group receiving citrate buffer (CB) in the autoimmune disease model mice “BXSB/MpJ-Yaa” (Yaa) and the wild-type strain BXSB/MpJ. Both strains showed hyperglycemia after 12 weeks of STZ injection. Interestingly, the Yaa group developed membranous and proliferative glomerulonephritis, which tended to be milder glomerular lesions in the STZ group than in the CB group, as indicated by a decreased mesangial area and ameliorated albuminuria. Statistically, the indices for hyperglycemia and autoimmune abnormalities were negatively and positively correlated with the histopathological parameters for mesangial matrix production and glomerular proliferative lesions, respectively. STZ treatment induced renal tubular anisonucleosis and dilations in both strains, and they were more severe in Yaa. Significantly decreased cellular infiltration was observed in the Yaa group compared to the CB group. Thus, in DKD related to autoimmune nephritis, hyperglycemia modifies its pathology by decreasing the mesangial area and interstitial inflammation and aggravating renal tubular injury.

Root cause determination of intraperitoneal catheter obstructions: Insulin amyloid aggregates vs foreign body reaction

Continuous intraperitoneal insulin infusion, from an implanted insulin pump connected to a catheter that delivers insulin directly to the peritoneal cavity has many clinical advantages for patients with Type 1 diabetes. However, the ongoing incidence of catheter obstructions remains a barrier to the widespread use of this therapy. To date, the root cause of these obstructions remains unknown. Here, a two-year clinical investigation was conducted, along with the development of an animal model to enable a mechanistic investigation into this issue. This novel animal model was able to mimic the catheter obstructions that occur in patients and, fortuitously, at an accelerated rate. This model allowed for independent assessment of each potential cause associated with catheter obstructions to help identify the root cause. Both macroscopic and microscopic analysis were conducted with regards to the onset and progression of catheter obstructions, along with monitoring of insulin delivery. Interestingly, although insulin aggregation occurs in insulin pumps and insulin aggregates were found in some catheter obstructions, insulin is unlikely to be the root cause, since obstructions also occurred in the control groups where only diluent (no insulin) was administered to the animals. Inflammatory cells, different phenotypes of fibroblasts, as well as collagen were observed in all obstructed catheters explanted from the patients and the animals. The presence of these cells and collagen is indicative of a typical foreign body reaction. In addition, the dynamic change in the fibroblasts with respect to morphology, phenotype, and spatial distribution suggests that tissue irritation-mediated epithelial to mesenchymal transition plays a role in catheter obstructions.

Bilobalide Enhances AMPK Activity to Improve Liver Injury and Metabolic Disorders in STZ-Induced Diabetes in Immature Rats via Regulating HMGB1/TLR4/NF-κB Signaling Pathway

This study was aimed at examining the effect and underlying mechanisms of bilobalide (BB) on hepatic injury in streptozotocin- (STZ-) induced diabetes mellitus (DM) in immature rats. Immature rats (one day old) were randomly divided into five groups: group I, control nondiabetic rats; group II, STZ-induced, untreated diabetic rats; groups III/IV/V, STZ-induced and BB-treated diabetic rats, which were intraperitoneally injected with BB (2.5 mg/kg, 5 mg/kg, or 10 mg/kg) after 3 days followed by STZ treatment. We observed that BB improved the histopathological changes and maintained normal glucose metabolism, blood lipid, and liver function indicators, such as fasting blood glucose, obesity index, HbA1c, HOMA-IR, fast serum insulin, adiponectin, total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), aspartate transaminase (AST), and alanine transaminase (ALT) in STZ-induced DM in immature rats by a biochemical analyzer or ELISA. Meanwhile, Western blot analysis showed that in STZ-induced DM immature rats, BB decreased the expression of apoptosis-related proteins Bax, cleaved caspase-3, and cleaved caspase-9 while enhancing the Bcl-2 expression; BB downregulated the expression of ACC related to fat anabolism, while upregulating the expression of CPT-1 related to fat catabolism. Strikingly, treatment with BB significantly increased the expression of AMPKα1 as well as inhibited HMGB1, TLR4, and p-P65 expression in hepatic tissues of immature DM rats. AMPK inhibitor (compound C, CC) cotreated with BB undermined the protective effect of BB on the liver injury. The results of the present study suggested BB may have a significant role in alleviating liver damage in the STZ-induced immature DM rats.

Lactoferrin and Immunoglobulin Concentrations in Milk of Gestational Diabetic Mothers

Gestational diabetes mellitus (GDM) is associated with an increased risk of having a high-care newborn and has an impact on maternal wellbeing. This study aimed to assess the effect of GDM on the lactoferrin (LF), secretory immunoglobulin A (SIgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) concentrations in early colostrum, colostrum, and transitional milk samples of hyperglycemic (n = 53) and normoglycemic (n = 49) mothers using enzyme-linked immunosorbent assay (ELISA). The concentrations of milk lactoferrin and SIgA, but not IgG and IgM, from hyperglycemic and normoglycemic mothers, showed a similar negative correlation with lactation from the first to the fifteenth day. Apart from early colostral IgG, there were no differences in concentrations of LF and immunoglobulins in milk from hyperglycemic and normoglycemic mothers. For hyperglycemia compensated by diet (GDM G1) or insulin treatment (GDM G2), slight differences were seen for LF and IgG, but not for SIgA and IgM, during an early stage of lactation only. Early colostral IgG and colostral LF of insulin-treated mothers were higher (10.01 ± 4.48 mg/L and 11.50 ± 0.58 g/L, respectively) than for diet-control diabetic mothers (7.65 ± 5.67 mg/L and 8.05 ± 1.38 g/L, respectively). GDM of mothers does not have a significant impact on immunological quality of early milk.

Altered VDAC-HK association and apoptosis in mouse peripheral blood lymphocytes exposed to diabetic condition: an in vitro and in vivo study

Increased apoptotic lymphocytes have been correlated to a high incidence of infection in poorly controlled diabetes. This study aimed to determine whether altered voltage-dependent anion channel (VDAC)-hexokinase (HK) association contributes to the increase in apoptosis. Mouse peripheral blood lymphocytes (PBL) exposed to high glucose (Glc)/palmitic acid (PA) were used as the in vitro model, which was compared with PBL isolated from alloxan-induced diabetic mice (in vivo model). Our results showed a significant increase in apoptosis as indicated by the apoptotic index, caspase-3 activity, mitochondrial membrane potential and ultrastructural study. HK and glucose-6-phosphate dehydrogenase (G6PDH) activities were markedly reduced with a profound increase in glucose-6-phosphate level. Co-immunoprecipitation confirms HK interaction with VDAC, an outer mitochondrial membrane protein. Inhibited glycolytic enzyme, i.e. HK and reduced HK-VDAC interaction in our study could contribute to increased apoptosis in lymphocytes exposed to high Glc/PA. Targeting HK-VDAC interaction may therefore provide therapeutic potential for the treatment of diabetes-associated infection.

Treatment of Diabetic Neuropathy with A Novel PAR1-Targeting Molecule

Diabetic peripheral neuropathy (DPN) is a disabling common complication of diabetes mellitus (DM). Thrombin, a coagulation factor, is increased in DM and affects nerve function via its G-protein coupled protease activated receptor 1 (PAR1).

METHODS

A novel PAR1 modulator (PARIN5) was designed based on the thrombin PAR1 recognition site. Coagulation, motor and sensory function and small fiber loss were evaluated by employing the murine streptozotocin diabetes model.

RESULTS

PARIN5 showed a safe coagulation profile and showed no significant effect on weight or glucose levels. Diabetic mice spent shorter time on the rotarod (p <0.001), and had hypoalgesia (p <0.05), slow conduction velocity (p <0.0001) and reduced skin innervation (p <0.0001). Treatment with PARIN5 significantly improved rotarod performance (p <0.05), normalized hypoalgesia (p <0.05), attenuated slowing of nerve conduction velocity (p <0.05) and improved skin innervation (p <0.0001).

CONCLUSION

PARIN5 is a novel pharmacological approach for prevention of DPN development, via PAR1 pathway modulation.

The Effects of Type 2 Diabetes Mellitus on Organ Metabolism and the Immune System

Metabolic abnormalities such as dyslipidemia, hyperinsulinemia, or insulin resistance and obesity play key roles in the induction and progression of type 2 diabetes mellitus (T2DM). The field of immunometabolism implies a bidirectional link between the immune system and metabolism, in which inflammation plays an essential role in the promotion of metabolic abnormalities (e.g., obesity and T2DM), and metabolic factors, in turn, regulate immune cell functions. Obesity as the main inducer of a systemic low-level inflammation is a main susceptibility factor for T2DM. Obesity-related immune cell infiltration, inflammation, and increased oxidative stress promote metabolic impairments in the insulin-sensitive tissues and finally, insulin resistance, organ failure, and premature aging occur. Hyperglycemia and the subsequent inflammation are the main causes of micro- and macroangiopathies in the circulatory system. They also promote the gut microbiota dysbiosis, increased intestinal permeability, and fatty liver disease. The impaired immune system together with metabolic imbalance also increases the susceptibility of patients to several pathogenic agents such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Thus, the need for a proper immunization protocol among such patients is granted. The focus of the current review is to explore metabolic and immunological abnormalities affecting several organs of T2DM patients and explain the mechanisms, whereby diabetic patients become more susceptible to infectious diseases.

Jabuticaba (Plinia trunciflora (O. Berg) Kausel) improved the lipid profile and immune system and reduced oxidative stress in streptozotocin-induced diabetic rats

The aim of this study was evaluating the effects of jabuticaba aqueous extract (JPE - 0.5 g/kg) on serum lipid levels, immune system, and oxidative stress parameters of streptozotocin-induced diabetic rats. Administration of JPE for 30 days, by gavage, was able to reduce serum levels of total cholesterol, non-high density lipoprotein (HDL) cholesterol, and triglycerides in diabetic rats. The HDL cholesterol levels increased in both diabetic and healthy rats after JPE treatment. Total leukocyte and lymphocyte counts reduced in diabetic rats, and JPE treatment prevented these diabetes mellitus (DM)-induced changes in the immune system. In addition, the induction of DM also led to dysregulation in the activity of superoxide dismutase and catalase antioxidant enzymes as well as an increase in oxidative stress markers. Treatments with JPE reduced oxidative stress and modulated antioxidant enzyme activities. These data demonstrate the potential of JPE as an adjuvant treatment option for diabetic patients. PRACTICAL APPLICATIONS: Considering that it is very common to observe dyslipidemia in diabetic patients and that these alterations, combined with the increased oxidative stress levels, also common in these patients, can lead to the development of cardiovascular diseases, JPE would be an alternative treatment adjunct to reduce these risks. In addition, although more studies are needed, JPE has the potential to improve the count of total lymphocytes and leukocytes, which could assist in improving the immune response of these patients, who also commonly have a higher risk of infectious diseases. Thus, JPE could be used by these patients, in combination with conventional treatment, in the form of a nutraceutical rich in phenolic compounds.

Activity-expression profiling of glucose-6-phosphate dehydrogenase in tissues of normal and diabetic mice

Glucose-6-phosphate dehydrogenase (G6PD) plays a principal role in the regulation of oxidative stress by modulating the nicotinamide adenine dinucleotide phosphate pool and is expected to be associated with metabolic diseases such as diabetes mellitus (DM). However, it is unclear whether hyperglycemia increases G6PD activity levels in DM because suitable assays for quantifying the activity in a high-throughput manner are lacking. Using liquid droplet arrays tailored to analyze tissue lysates, we performed G6PD activity profiling in eight tissues of normal and diabetic mice: brain, heart, kidney, liver, lung, muscle, spleen, and thyroid. Diabetic mice exhibited significantly higher G6PD activities in the kidney, liver, spleen, and thyroid than normal mice; no significant difference was found in the brain, heart, lung, or muscle. We also performed G6PD expression profiling in the eight tissues using Western blot analysis. Diabetic mice showed significantly elevated G6PD expression levels in the kidney, lung, spleen, and thyroid compared with normal mice; no significant difference was found in the brain, heart, liver, or muscle. An analysis of G6PD activity-expression profiles demonstrated tissue-specific changes in response to hyperglycemia. Thus, our approach would be helpful for understanding the role of G6PD in tissue-based pathogenesis of diabetic complications.

Local and Systemic Immune Dysregulation Alters Glioma Growth in Hyperglycemic Mice

PURPOSE

Unlike most cancers, no clear epidemiological correlation between diabetes (Db) and malignant glioma progression exists. Because hyperglycemia activates proinflammatory pathways through the receptor for advanced glycation endproducts (RAGE), we hypothesized that Db can also promote malignant glioma progression.

EXPERIMENTAL DESIGN

We compared the growth of two phenotypically diverse syngeneic glioma models in control and diabetic mice. Tumor growth and antitumor immune responses were evaluated in orthotopic and heterotopic models and correlated to RAGE and RAGE ligand expression.

RESULTS

Irrespective of tumor implantation site, growth of a "classical" glioma model, GL261, increased in hyperglycemic mice and was mediated by upregulation of RAGE and its ligand, HMGB1. However, growth of a "mesenchymal" glioma subtype, K-Luc, depended on tumor implantation site. Whereas heterotopic K-Luc tumors progressed rapidly in Db mice, intracranial K-Luc tumors grew slower. We further showed that hyperglycemia inhibited the innate antitumor inflammatory responses in both models. Although this contributed to the accelerated growth of heterotopic tumors, suppression of tumor inflammatory responses dampened the growth of orthotopic K-Luc gliomas.

CONCLUSIONS

Hyperglycemia may enhance glioma growth through promotion of RAGE expression and suppression of antitumor immune responses. However, abrogation of the proinflammatory milieu in tumors may also dampen the growth of inflammatory glioma subtypes in the brains of diabetic mice. This dichotomy in glioma growth response to hyperglycemia may partly explain why conflicting epidemiological studies show both an increased risk and a protective effect of Db in patients with malignant gliomas.

Glucose-6-phosphate dehydrogenase deficiency increases cell adhesion molecules and activates human monocyte-endothelial cell adhesion: Protective role of l-cysteine

Glucose-6-phosphate dehydrogenase is a major enzyme that supplies the reducing agent nicotinamide adenine dinucleotide phosphate hydrogen (NADPH), which is required to recycle oxidized/glutathione disulfide (GSSH) to reduced glutathione (GSH). G6PD-deficient cells are susceptible to oxidative stress and a deficiency of GSH. Endothelial dysfunction is characterized by the loss of nitric oxide (NO) bioavailability, which regulates leukocyte adhesion to endothelium. G6PD-deficient endothelial cells (EC) demonstrate reduced expression of endothelial nitric oxide synthase (eNOS) and NO levels along with reduced GSH. Whether G6PD deficiency plays any role in EC dysfunction is unknown. The chronic inflammation commonly seen in those with metabolic syndrome, characterized by elevated levels of tumor necrosis factor (TNF) and monocyte chemoattractant protein 1 (MCP-1), provided an incentive for investigation of these cytokines as well. A GSH/G6PD-deficient model was created using human umbilical vein endothelial cells (HUVEC) treated with either buthionine sulfoximine (BSO), a pharmacological inhibitor of the rate-limiting enzyme of GSH biosynthesis (γ-glutamylcysteine synthetase), or with 6-aminonicotinamide (6-AN), an inhibitor of G6PD or G6PD siRNA. Normal and G6PD-deficient cells were also treated with pro-atherosclerotic stimuli such as high glucose, TNF, and MCP-1. After inhibiting or knocking down G6PD/GSH, the capacity of endothelial cells for monocyte recruitment was assessed by determining the expression of the adhesion molecules intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), which was upregulated by G6PD deficiency and accompanied by the presence of the oxidative stress markers NADPH oxidase 4 (NOX4), inducible nitric oxide synthase (iNOS), and reactive oxygen species (ROS). Treatment with the inhibitors BSO and 6-AN caused increased levels of adhesion molecule mRNA and monocyte-EC adhesion. Following treatment with high glucose, G6PD-deficient cells showed an increase in levels of ICAM-1 and VCAM-1 mRNA, as well as monocyte-EC adherence, compared with results seen in control cells. Treatment with l-cysteine (a precursor of GSH) protected endothelial cells by increasing GSH and attenuating ROS, ICAM-1, VCAM-1, and monocyte-EC adhesion. These results suggest that G6PD/GSH deficiency plays a role in endothelial dysfunction and that supplementation with l-cysteine can restore GSH levels and reduce the EC activation markers in G6PD-deficient conditions.

Diabetes and the solid organ transplant recipient

Solid organ transplant candidates undergo very strict screening for cardiovascular risk. Such screening has permitted significant decreases in cardiovascular morbidity and mortality over the ensuing decades of follow up. Long term follow-up has enabled us to identify an increasing incidence of pulmonary and urinary tract infections with or without sepsis as competing factors of morbidity and mortality. Indeed, all-cause mortality may now be dominated by infection-related endpoints. No population of transplant recipients is more naturally susceptible to infection as a diabetic subset, now submitted to immunosuppression. The current review details infection risk for kidney, liver, heart, and lung allograft recipients. A specific feature of this report emphasizes the enhanced risk for bacterial and fungal infection found in diabetic allograft recipients on immunosuppression therapy. The risk of repeated prescription of antibiotics in terms of evolutions of resistant strains of infectious pathogens is emphasized.

Hydrogen sulfide increases glutathione biosynthesis, and glucose uptake and utilisation in C2C12 mouse myotubes

Diabetic patients have lower blood concentrations of hydrogen sulfide (H₂S), L-cysteine (LC), and glutathione (GSH). Using C₂C₁₂ mouse myotubes as a model, this study investigates the hypothesis that the beneficial effects of LC supplementation are mediated by upregulation of the H₂S status under diabetic conditions. Results show that exogenous administration of sodium hydrosulfide (NaHS, 10 or 20 µM; 6 hours), a H₂S donor, significantly (p < .05) upregulates the gene expression of cystathionine-γ-lyase (CSE), LC transporter (Slc7a11/xCT), and the genes involved in GSH biosynthesis. Additionally, it reduces homocysteine (HCys), reactive oxygen species (ROS) production, and enhances cellular LC, H₂S, and glucose uptake and utilisation in myoblasts. The use of CSE siRNA to induce deficient endogenous H₂S production causes an increase in H₂O₂, ROS, HCys levels, and downregulation of GSH biosynthesis pathway enzymes. In additional, CSE knockdown downregulates glucose transporter type 4 (GLUT4) and gene expression of its key transcription factors, and reduces glucose uptake in C₂C₁₂ myotubes. CSE knockdown cells showed specific increases in the protein S-glutathionylation of LC transporter and GLUT4 along with increased total protein S-glutathionylation. Taken together, evidence from this study provides molecular insights into the importance of the CSE/H₂S system in maintaining the cellular glutathione and glucose homeostasis in C₂C₁₂ myotubes.

L-Cysteine in vitro can restore cellular glutathione and inhibits the expression of cell adhesion molecules in G6PD-deficient monocytes

L-Cysteine is a precursor of glutathione (GSH), a potent physiological antioxidant. Excess glucose-6-phosphate dehydrogenase (G6PD) deficiency in African Americans and low levels of L-cysteine diet in Hispanics can contributes to GSH deficiency and oxidative stress. Oxidative stress and monocyte adhesion was considered to be an initial event in the progression of vascular dysfunction and atherosclerosis. However, no previous study has investigated the contribution of GSH/G6PD deficiency to the expression of monocyte adhesion molecules. Using human U937 monocytes, this study examined the effect of GSH/G6PD deficiency and L-cysteine supplementation on monocyte adhesion molecules. G6PD/GSH deficiency induced by either siRNA or inhibitors (6AN/BSO, respectively) significantly (p < 0.005) increased the levels of cell adhesion molecules (ICAM-1, VCAM-1, SELL, ITGB1 and 2); NADPH oxidase (NOX), reactive oxygen species (ROS) and MCP-1 were upregulated, and decreases in levels of GSH, and nitric oxide were observed. The expression of ICAM-1 and VCAM-1 mRNA levels increased in high glucose, MCP-1 or TNF-α-treated G6PD-deficient compared to G6PD-normal cells. L-Cysteine treatment significantly (p < 0.005) increased G6PD activity and levels of GSH, and decreased NOX, ROS, and adhesion molecules. Thus, GSH/G6PD deficiency increases susceptibility to monocyte adhesion processes, whereas L-cysteine supplementation can restore cellular GSH/G6PD and attenuates NOX activity and expression of cell adhesion molecules.

The association of admission hyperglycaemia and adverse clinical outcome in medical emergencies: the multinational, prospective, observational TRIAGE study

AIMS

The clinical relevance of hyperglycaemia in an emergency department population remains incompletely understood. We investigated the association between admission blood glucose levels and adverse clinical outcomes in a large emergency department cohort.

METHODS

We prospectively enrolled 7132 adult medical patients seeking emergency department care in three tertiary care hospitals in Switzerland, France and the USA. We used adjusted multivariable logistic regression models to examine the association between admission blood glucose levels and 30-day mortality, as well as adverse clinical course stratified by pre-existing diabetes and principal medical diagnoses.

RESULTS

In 6044 people without diabetes (84.7%), severe hyperglycaemia, defined as a glucose level of > 11.1 mmol/l (200 mg/dl), was associated with a doubling in the risk of 30-day mortality [adjusted odds ratio (OR) 1.9; 95% confidence interval (95% CI), 1.1 to 3.3; P = 0.018] and a three-fold increase in the risk of intensive care unit admission (adjusted OR 3.0; 95% CI, 1.9 to 4.9; P < 0.001). These associations were similar among different diagnoses. In the population with diabetes (n = 1088), no association with 30-day mortality was found (adjusted OR 1.0; 95% CI, 0.6 to 1.8; P for interaction = 0.001), whereas the association with intensive care unit admission was weaker (adjusted OR 2.4; 95% CI, 1.5 to 4.1; P for interaction = 0.011). Overall 30-day mortality was higher in those with diabetes than in those without (6.1 vs. 4.4%, P = 0.015).

CONCLUSIONS

In this large medical emergency department patient cohort, admission hyperglycaemia was strongly associated with adverse clinical course in people without diabetes. (Clinical Trial Registry No: NCT01768494).

Relationships between acrylamide and glycidamide hemoglobin adduct levels and allergy-related outcomes in general US population, NHANES 2005-2006

BACKGROUND

Acrylamide-induced immunotoxicity and allergic dermatitis have been reported in animal experiments and clinical reports, respectively. However, epidemiological evidence from the general population is limited.

OBJECTIVES

The purpose of the present study was to estimate the associations between acrylamide exposure and allergy-related outcomes in the general US population.

METHODS

A total of 6982 subjects were selected from the National Health and Nutrition Examination Survey 2005-2006 (NHANES). Internal exposure was measured by the hemoglobin adducts of acrylamide (HbAA) and its metabolite glycidamide (HbGA). Allergy-related outcomes including asthma, hay fever, allergy, itchy rash, sneeze, wheeze and eczema were obtained by self-administered questionnaires. Allergic sensitization was assessed by the total immunoglobulin E (IgE) levels. The associations of HbAA and HbGA quartiles with allergy-related outcomes were calculated using logistic regression models with multivariable adjustments. Analyses were additionally stratified according to age, gender and serum cotinine levels.

RESULTS

When setting quartile 1 of HbAA as reference, the odds ratios (ORs) [95% confidence intervals (CIs)] of quartile 2 to 4 for eczema were 1.18 (0.79-1.76), 1.14 (0.73-1.78) and 1.58 (1.14-2.18), respectively (p_trend = 0.002). Individuals at the highest quartile of HbGA had significantly elevated likelihoods of itchy rash (OR = 1.37, 95% CI = 1.02-1.83, p_trend = 0.032) and eczema (OR = 1.45, 95% CI = 1.06-1.97, p_trend = 0.044). The stratification analyses indicated various results in different subgroups.

CONCLUSIONS

This study indicated significant associations between HbAA and HbGA levels and the likelihoods of allergy-related outcomes in the general US population, depending on age, gender and smoke exposure status. These findings suggested potential public health concerns for the widespread exposure to acrylamide.

Relationship between Immunological Abnormalities in Rat Models of Diabetes Mellitus and the Amplification Circuits for Diabetes

A better understanding of pathogenic mechanisms is required in order to treat diseases. However, the mechanisms of diabetes mellitus and diabetic complications are extremely complex. Immune reactions are involved in the pathogenesis of diabetes and its complications, while diabetes influences immune reactions. Furthermore, both diabetes and immune reactions are influenced by genetic and environmental factors. To address these issues, animal models are useful tools. So far, various animal models of diabetes have been developed in rats, which have advantages over mice models in terms of the larger volume of tissue samples and the variety of type 2 diabetes models. In this review, we introduce rat models of diabetes and summarize the immune reactions in diabetic rat models. Finally, we speculate on the relationship between immune reactions and diabetic episodes. For example, diabetes-prone Biobreeding rats, type 1 diabetes model rats, exhibit increased autoreactive cellular and inflammatory immune reactions, while Goto-Kakizaki rats, type 2 diabetes model rats, exhibit increased Th2 reactions and attenuation of phagocytic activity. Investigation of immunological abnormalities in various diabetic rat models is useful for elucidating complicated mechanisms in the pathophysiology of diabetes. Studying immunological alterations, such as predominance of Th1/17 or Th2 cells, humoral immunity, and innate immune reactions, may improve understanding the structure of amplification circuits for diabetes in future studies.

Effect of Diet and Exercise on the Peripheral Immune System in Young Balb/c Mice

Although diet and exercise clearly have an influence on immune function, studies are scarce on the effect caused by exercise and the consumption of a carbohydrate-rich or fat-rich diet on the peripheral immune system. The aim of the present study was to evaluate the effect of exercise and the two aforementioned unbalanced diets on young Balb/c mice, especially in relation to BMI, the level of glucose, and the percentage of lymphocyte subpopulations in peripheral blood. The changes found were then related to the synthesis of leptin and adiponectin as well as the production of oxidative stress. The increase in BMI found with the carbohydrate-rich and fat-rich diets showed correlation with the levels of leptin and adiponectin. An increase in leptin and a decrease in adiponectin directly correlated with an increase in total lymphocytes and CD4+ cells and with a decrease in B cells. The increase in leptin also correlated with an increase in CD8+ cells. Glycemia and oxidative stress increased with the two unbalanced diets, negatively affecting the proliferation of total lymphocytes and the percentage of B cells, apparently by causing alterations in proteins through carbonylation. These alterations caused by an unbalanced diet were not modified by moderate exercise.

Immunotoxicological effects of streptozotocin and alloxan: in vitro and in vivo studies

Streptozotocin (STZ) and alloxan (ALX), widely used to induce diabetes in experimental animals, have different structures and mechanisms of action. We investigated those effects of these drugs on the immune system that might influence engraftment efficiency and graft survival in transplantation models, and their cytotoxicity on hematopoietic cell lines. We used the minimum dose to induce diabetes in a mouse, i.e. 180 mg/kg i.v. STZ and 75 mg/kg i.v. ALX. Both groups exhibited significant decrease in body weight during 4 days post-treatment as compared to controls. We found that blood glucose in ALX-injected mice increased faster than in STZ-injected mice. The total number of recovered splenocytes was lower in STZ-injected animals than in ALX-injected animals. The survival periods of rat islet grafts in recipient mice were longer and more diverse in STZ-injected recipients (7-24 days) compared to ALX-injected recipients (6-7 days). The in vitro study showed that ALX was less cytotoxic in cell lines with IC50 values of 2809, 3679 and >4000 μg/ml for HL60, K562 and C1498 cells respectively. STZ was more toxic, especially in HL60 cells, with IC50 values of 11.7, 904 and 1024 μg/ml for HL60, K562 and C1498 cells respectively. Furthermore, in response to concanavalin A (Con-A), splenocytes from STZ-injected mice produced higher amounts of interferon-gamma (IFN-γ) than those from ALX-injected mice. In conclusion, STZ was more cytotoxic than ALX in vitro and in vivo. STZ caused lymphocytopenia, which may result in longer graft survival in STZ-treated animals than in ALX-treated animals.

Does PGE₁ vasodilator prevent orthopaedic implant-related infection in diabetes? Preliminary results in a mouse model

BACKGROUND

Implant-related infections are characterized by bacterial colonization and biofilm formation on the prosthesis. Diabetes represents one of the risk factors that increase the chances of prosthetic infections because of related severe peripheral vascular disease. Vasodilatation can be a therapeutic option to overcome diabetic vascular damages and increase the local blood supply. In this study, the effect of a PGE₁ vasodilator on the incidence of surgical infections in diabetic mice was investigated.

METHODOLOGY

A S. aureus implant-related infection was induced in femurs of diabetic mice, then differently treated with a third generation cephalosporin alone or associated with a PGE₁ vasodilator. Variations in mouse body weight were evaluated as index of animal welfare. The femurs were harvested after 28 days and underwent both qualitative and quantitative analysis as micro-CT, histological and microbiological analyses.

RESULTS

The analysis performed in this study demonstrated the increased host response to implant-related infection in diabetic mice treated with the combination of a PGE₁ and antibiotic. In this group, restrained signs of infections were identified by micro-CT and histological analysis. On the other hand, the diabetic mice treated with the antibiotic alone showed a severe infection and inability to successfully respond to the standard antimicrobial treatment.

CONCLUSIONS

The present study revealed interesting preliminary results in the use of a drug combination of antibiotic and vasodilator to prevent implant-related Staphylococcus aureus infections in a diabetic mouse model.

Decreased cystathionine-γ-lyase (CSE) activity in livers of type 1 diabetic rats and peripheral blood mononuclear cells (PBMC) of type 1 diabetic patients

The liver plays a major role in the formation of H2S, a novel signaling molecule. Diabetes is associated with lower blood levels of H2S. This study investigated the activities of cystathionine-γ-lyase (CSE, the enzyme that catalyzes H2S formation) in livers of type 1 diabetic (T1D) animals and in peripheral blood mononuclear cells (PBMC) isolated from T1D patients. T1D is associated with both hyperketonemia (acetoacetate and β-hydroxybutyrate) and hyperglycemia. This study also examined the role of hyperglycemia and hyperketonemia per se in decreased CSE activity using U937 monocytes and PBMC isolated from healthy subjects. Livers from streptozotocin-treated T1D rats demonstrated a significantly higher reactive oxygen species production, lower CSE protein expression and activity, and lower H2S formation compared with those of controls. Studies with T1D patients showed a decrease in CSE protein expression and activity in PBMC compared with those of age-matched normal subjects. Cell culture studies demonstrated that high glucose (25 mm) and/or acetoacetate (4 mm) increased reactive oxygen species, decreased CSE mRNA expression, protein expression, and enzymatic activity, and reduced H2S levels; however, β-hydroxybutyrate treatment had no effect. A similar effect, which was also observed in PBMC treated with high glucose alone or along with acetoacetate, was prevented by vitamin D supplementation. Studies with CSE siRNA provide evidence for a relationship between impaired CSE expression and reduced H2S levels. This study demonstrates for the first time that both hyperglycemia and hyperketonemia mediate a reduction in CSE expression and activity, which can contribute to the impaired H2S signaling associated with diabetes.

[Immunological disorders of diabetes mellitus in experimental rat models]

A comprehensive understanding of the pathogenic mechanism is the prerequisite for proper disease management. However, the mechanisms of diabetes mellitus and diabetic complication remain extremely complicated and unresolved. While immune reactions are involved in the pathogenesis of diabetes and diabetic complication, the diabetic condition itself can influence immune responses. Furthermore, both diabetes and immune reactions are regulated by genetic and environmental factors. As a result, animal models have evolved to be powerful research tools to elucidate the complicated mechanisms for the pathogenesis of diabetes. Recently, various animal models of diabetes have been developed in rats, which provide advantages over mouse models in the scale of tissue samples and variation in type 2 diabetes models. In this review, we introduced rat models of diabetes and summarized the immune reactions in diabetic rats to propose the relationship between immune reactions and diabetes. Type 1 diabetes is induced by self-reactive cellular immune reactions. On the other hand, type 2 diabetes in rat models is associated with augmentation of innate immune reactions and increased humoral immunity. For example, helper T (Th) 1/Th17 cells are prevalent in non-obese type 1 diabetes rats (diabetes-prone BioBreeding rats), while non-obese type 2 diabetes rats (Goto-Kakizaki rat) show higher levels of natural IgM and T cell ratios with elevated Th2 cells compared with Wister rats. The investigation of immunological disorders in various diabetic rat models is useful to elucidate complicated mechanisms for the pathophysiology of diabetes. In future studies, immunological experimentations altering Th1/Th17 or Th2 cell levels and natural immune reactions may lend support to understanding the causes of diabetes and predicting the pathological conditions in diabetes.

Glucose impairs B-1 cell function in diabetes

B-1 lymphocytes produce natural immunoglobulin (Ig)M, among which a large proportion is directed against apoptotic cells and altered self-antigens, such as modified low-density lipoprotein (LDL). Thereby, natural IgM maintains homeostasis in the body and is also protective against atherosclerosis. Diabetic patients have an increased risk of developing certain infections as well as atherosclerosis compared with healthy subjects, but the underlying reason is not known. The aim of this study was to investigate whether diabetes and insulin resistance affects B-1 lymphocytes and their production of natural IgM. We found that diabetic db/db mice had lower levels of peritoneal B-1a cells in the steady state-condition compared to controls. Also, activation of B-1 cells with the Toll-like receptor (TLR)-4 agonist Kdo2-Lipid A or immunization against Streptococcus pneumoniae led to a blunted IgM response in the diabetic db/db mice. In-vitro experiments with isolated B-1 cells showed that high concentrations of glucose, but not insulin or leptin, caused a reduced secretion of total IgM and copper-oxidized (CuOx)-LDL- and malondialdehyde (MDA)-LDL-specific IgM from B-1 cells in addition to a decreased differentiation into antibody-producing cells, proliferation arrest and increased apoptosis. These results suggest that metabolic regulation of B-1 cells is of importance for the understanding of the role of this cell type in life-style-related conditions.

Human milk secretory immunoglobulin a and lactoferrin N-glycans are altered in women with gestational diabetes mellitus

Very little is known about the effects of gestational diabetes mellitus (GDM) on lactation and milk components. Recent reports suggested that hyperglycemia during pregnancy was associated with altered breast milk immune factors. Human milk oligosaccharides (HMOs) and N-glycans of milk immune-modulatory proteins are implicated in modulation of infant immunity. The objective of the current study was to evaluate the effect of GDM on HMO and protein-conjugated glycan profiles in breast milk. Milk was collected at 2 wk postpartum from women diagnosed with (n = 8) or without (n = 16) GDM at week 24-28 in pregnancy. Milk was analyzed for HMO abundances, protein concentrations, and N-glycan abundances of lactoferrin and secretory immunoglobulin A (sIgA). HMOs and N-glycans were analyzed by mass spectrometry and milk lactoferrin and sIgA concentrations were analyzed by the Bradford assay. The data were analyzed using multivariate modeling confirmed with univariate statistics to determine differences between milk of women with compared with women without GDM. There were no differences in HMOs between milk from women with vs. without GDM. Milk from women with GDM compared with those without GDM was 63.6% lower in sIgA protein (P < 0.05), 45% higher in lactoferrin total N-glycans (P < 0.0001), 36-72% higher in lactoferrin fucose and sialic acid N-glycans (P < 0.01), and 32-43% lower in sIgA total, mannose, fucose, and sialic acid N-glycans (P < 0.05). GDM did not alter breast milk free oligosaccharide abundances but decreased total protein and glycosylation of sIgA and increased glycosylation of lactoferrin in transitional milk. The results suggest that maternal glucose dysregulation during pregnancy has lasting consequences that may influence the innate immune protective functions of breast milk.

Diabetic mouse model of orthopaedic implant-related Staphylococcus aureus infection

Background

Periprosthetic bacterial infections represent one of the most challenging orthopaedic complications that often require implant removal and surgical debridement and carry high social and economical costs. Diabetes is one of the most relevant risk factors of implant-related infection and its clinical occurrence is growing worldwide. The aim of the present study was to test a model of implant-related infection in the diabetic mouse, with a view to allow further investigation on the relative efficacy of prevention and treatment options in diabetic and non-diabetic individuals.

Methodology

A cohort of diabetic NOD/ShiLtJ mice was compared with non-diabetic CD1 mice as an in vivo model of S. aureus orthopaedic infection of bone and soft tissues after femur intramedullary pin implantation. We tested control and infected groups with 1×10³ colony-forming units of S. aureus ATCC 25923 strain injected in the implant site. At 4 weeks post-inoculation, host response to infection, microbial biofilm formation, and bone damage were assessed by traditional diagnostic parameters (bacterial culture, C-reactive protein and white blood cell count), histological analysis and imaging techniques (micro computed tomography and scanning electron microscopy).

Results

Unlike the controls and the CD1 mice, all the diabetic mice challenged with a single inoculum of S. aureus displayed severe osteomyelitic changes around the implant.

Conclusions

Our findings demonstrate for the first time that the diabetic mouse can be successfully used in a model of orthopaedic implant-related infection. Furthermore, the same bacteria inoculum induced periprosthetic infection in all the diabetic mice but not in the controls. This animal model of implant-related infection in diabetes may be a useful tool to test in vivo treatments in diabetic and non-diabetic individuals.

Vitamin D upregulates glutamate cysteine ligase and glutathione reductase, and GSH formation, and decreases ROS and MCP-1 and IL-8 secretion in high-glucose exposed U937 monocytes

INTRODUCTION

Glutathione is a major endogenous antioxidant and its deficiency is implicated in the etiology and progression of a number of human diseases. Vitamin D is important for the prevention of osteoporosis, cardiovascular disease, diabetes, autoimmune diseases, and some cancers. Using a monocyte cell model, this study examined the hypothesis that vitamin D upregulate glutamate cysteine ligase (GCLC) and glutathione reductase (GR), which catalyzes GSH biosynthesis.

METHODS

U937 monocytes were pretreated with and without 1,25 (OH)₂ vitamin D (10-25 nM) for 24 h and then exposed to control and high glucose (HG, 25 mM) for 4h. Levels of GSH determined using HPLC; GR activity by oxidation of NADPH; GCLC protein, MCP-1 and IL-8 using ELISA kits.

RESULTS

1,25 (OH)₂ vitamin D supplementation significantly upregulated expression of GCLC and GR, levels of GCLC protein and GR activity, and formation of GSH in control and HG-treated monocytes. 1,25 (OH)₂ vitamin D caused significantly (p<0.05) lower secretion of IL-8 and MCP-1, and lower ROS levels in monocytes exposed to control and HG-treated monocytes.

CONCLUSIONS

This study demonstrates a positive link between vitamin D and GSH levels, and that some beneficial effects of vitamin D supplementation may be mediated by an improvement in the cellular GSH levels and a decrease in ROS and pro-inflammatory cytokines.

Diabetes alters activation and repression of pro- and anti-inflammatory signaling pathways in the vasculature

A central mechanism driving vascular disease in diabetes is immune cell-mediated inflammation. In diabetes, enhanced oxidation and glycation of macromolecules, such as lipoproteins, insults the endothelium, and activates both innate and adaptive arms of the immune system by generating new antigens for presentation to adaptive immune cells. Chronic inflammation of the endothelium in diabetes leads to continuous infiltration and accumulation of leukocytes at sites of endothelial cell injury. We will describe the central role of the macrophage as a source of signaling molecules and damaging by-products which activate infiltrating lymphocytes in the tissue and contribute to the pro-oxidant and pro-inflammatory microenvironment. An important aspect to be considered is the diabetes-associated defects in the immune system, such as fewer or dysfunctional athero-protective leukocyte subsets in the diabetic lesion compared to non-diabetic lesions. This review will discuss the key pro-inflammatory signaling pathways responsible for leukocyte recruitment and activation in the injured vessel, with particular focus on pro- and anti-inflammatory pathways aberrantly activated or repressed in diabetes. We aim to describe the interaction between advanced glycation end products and their principle receptor RAGE, angiotensin II, and the Ang II type 1 receptor, in addition to reactive oxygen species (ROS) production by NADPH-oxidase enzymes that are relevant to vascular and immune cell function in the context of diabetic vasculopathy. Furthermore, we will touch on recent advances in epigenetic medicine that have revealed high glucose-mediated changes in the transcription of genes with known pro-inflammatory downstream targets. Finally, novel anti-atherosclerosis strategies that target the vascular immune interface will be explored; such as vaccination against modified low-density lipoprotein and pharmacological inhibition of ROS-producing enzymes.

Differential effect of hyperglycaemia on the immune response in an experimental model of diabetes in BALB/cByJ and C57Bl/6J mice: participation of oxidative stress

Diabetes is associated with an increased risk of death from infectious disease. Hyperglycaemia has been identified as the main factor contributing to the development of diseases associated with diabetes mellitus. However, experimental evidence indicates individual susceptibility to develop complications of diabetes. In this context, the aim of this work was to study the immune response in a streptozotocin-induced type 1 diabetes in two mouse strains: BALB/cByJ and C57Bl/6J. The participation of hyperglycaemia and oxidative stress was also analysed. Diabetic BALB/cByJ mice showed a decrease in both the in-vivo and in-vitro immune responses, whereas diabetic C57Bl/6J mice had higher blood glucose but exhibited no impairment of the immune response. The influence of hyperglycaemia over the immune response was evaluated by preincubation of lymphocytes from normal mice in a high glucose-containing medium. T and B cells from BALB/cByJ mice showed a decrease in cell viability and mitogen-stimulated proliferation and an increase in apoptosis induction. An increase in oxidative stress was implicated in this deleterious effect. These parameters were not affected in the T and B lymphocytes from C57Bl/6J mice. In conclusion, BALB/cByJ mice were sensitive to the deleterious effect of hyperglycaemia, while C57BL/6J were resistant. Although an extrapolation of these results to clinical conditions must be handled with caution, these results highlight the need to contemplate the genetic background to establish models to study the deleterious effect of diabetes in order to understand phenotypical variations that are of clinical importance in the treatment of patients.

High glucose impairs ATP formation on the surface of human peripheral blood B lymphocytes

Diabetes-associated lymphocyte dysfunction may be attributed to the direct effect of hyperglycemia, but the impact of glucose concentration on B cell functionality is not fully resolved. Since, adenosine 5'-triphosphate (ATP) and its metabolite adenosine are the core constituents of the purinergic signaling network involved in regulation of immune response we aimed to investigate the impact of high glucose concentration on ATP outflow and metabolism on B cell surface. Purified human peripheral blood B cells cultured at high glucose (25 mM) concentration released significantly less ATP (~60%) comparing to cells cultured in low glucose (5mM) concentration. We observed that high glucose altered ATP hydrolysis on B cell surface due to increased activity of nucleoside triphosphate diphosphohydrolase-1 (NTPDase-1/CD39). In the presence of 10 μM [(3)H]AMP and 100 μM ATP significant quantities of [(3)H]ADP and [(3)H]ATP were generated, although the AMP to ADP phosphorylation potential of B cells cultured in high glucose decreased significantly. The flow cytometry analysis revealed that the level of ecto-adenylate kinase 1β (AK1β) on surface of B cells cultured in high glucose decreased significantly. Inhibition of NTPDase1/CD39 activity with 100 μM ARL67156 resulted in decreased cell viability, although significantly more viable cells retained in the culture media containing low glucose compared to high glucose media. Selective inhibition of P2X7 purinergic receptor irrespective of glucose concentration completely protected B cells against the ARL 67156-induced cell death. We assume that high glucose-induced alteration of ATP handling on B cell surface might contribute to impaired functionality of B cells in diabetes.

Teplizumab treatment may improve C-peptide responses in participants with type 1 diabetes after the new-onset period: a randomised controlled trial

AIMS/HYPOTHESIS

Type 1 diabetes results from a chronic autoimmune process continuing for years after presentation. We tested whether treatment with teplizumab (a Fc receptor non-binding anti-CD3 monoclonal antibody), after the new-onset period, affects the decline in C-peptide production in individuals with type 1 diabetes.

METHODS

In a randomised placebo-controlled trial we treated 58 participants with type 1 diabetes for 4-12 months with teplizumab or placebo at four academic centres in the USA. A central randomisation centre used computer generated tables to allocate treatments. Investigators, patients, and caregivers were blinded to group assignment. The primary outcome was a comparison of C-peptide responses to a mixed meal after 1 year. We explored modification of treatment effects in subgroups of patients.

RESULTS

Thirty-four and 29 subjects were randomized to the drug and placebo treated groups, respectively. Thirty-one and 27, respectively, were analysed. Although the primary outcome analysis showed a 21.7% higher C-peptide response in the teplizumab-treated group (0.45 vs 0.371; difference, 0.059 [95% CI 0.006, 0.115] nmol/l) (p = 0.03), when corrected for baseline imbalances in HbA(1c) levels, the C-peptide levels in the teplizumab-treated group were 17.7% higher (0.44 vs 0.378; difference, 0.049 [95% CI 0, 0.108] nmol/l, p = 0.09). A greater proportion of placebo-treated participants lost detectable C-peptide responses at 12 months (p = 0.03). The teplizumab group required less exogenous insulin (p < 0.001) but treatment differences in HbA(1c) levels were not observed. Teplizumab was well tolerated. A subgroup analysis showed that treatment benefits were larger in younger individuals and those with HbA(1c) <6.5% at entry. Clinical responders to teplizumab had an increase in circulating CD8 central memory cells 2 months after enrolment compared with non-responders.

CONCLUSIONS/INTERPRETATIONS

This study suggests that deterioration in insulin secretion may be affected by immune therapy with teplizumab after the new-onset period but the magnitude of the effect is less than during the new-onset period. Our studies identify characteristics of patients most likely to respond to this immune therapy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00378508

FUNDING

This work was supported by grants 2007-502, 2007-1059 and 2006-351 from the JDRF and grants R01 DK057846, P30 DK20495, UL1 RR024139, UL1RR025780, UL1 RR024131 and UL1 RR024134 from the NIH.

Korean red ginseng (Panax ginseng) ameliorates type 1 diabetes and restores immune cell compartments

ETHNOPHARMACOLOGICAL RELEVANCE

Historical records reveal that in traditional medicine, a disease similar to diabetes was treated with ginseng. Korean red ginseng has been considered beneficial as a dietary supplement for its anti-diabetic potential.

AIM

This study was designed to investigate the prophylactic potential of Korean red ginseng (KRG) extract (Panax ginseng C.A. Meyer Radix Rubra) in a well-established mouse model of Type 1 diabetes (T1D).

MATERIALS AND METHODS

The prophylactic effect of KRG extract was evaluated in mice fed with KRG extract for two weeks prior to induction of diabetes by streptozotocin (STZ) administration. Glucose levels and glucose challenge test results of KRG-treated diabetic mice were compared to those of untreated diabetic mice and healthy control mice. Examination of the immune compartments in lymphoid organs and immunohistochemical staining of pancreas for islet cell morphology and insulin producing beta cells were performed.

RESULTS

KRG extract significantly lowered blood glucose levels to an average of 250mg/dl from 350mg/dl and improved glucose challenge testing when applied as prophylaxis. Histological findings indicated that KRG extract protected against STZ-induced destruction of pancreatic tissue and restored insulin secretion. Strikingly, this effect was accompanied by restoration of lymphocytes in secondary lymphoid organs, suggesting that KRG extract facilitated immune homeostasis.

CONCLUSION

This is the first report to demonstrate the prophylactic function of KRG extract in ameliorating the hyperglycemia of T1D. Immune compartments of diabetic mice were found to be preserved in KRG-treated mice suggesting that Korean red ginseng may benefit T1D patients, not only for its hypoglycemic but also for its immunomodulatory effects.

High glucose concentration impairs ATP outflow and immunoglobulin production by human peripheral B lymphocytes: involvement of P2X7 receptor

AIMS/HYPOTHESIS

Patients with diabetes are more prone to bacterial infections mostly due to hyperglycemia-induced suppression of immune cells function. B lymphocytes by secreting antibodies inhibit microbial replication, but the impact of high glucose concentration on humoral immune response is not fully resolved. The aim of this work was to investigate the effect of high glucose concentration on B cells response to stimulation with a bacterial antigen and autocrine regulation.

METHODS

Purified human peripheral blood B cells were cultured at different glucose concentrations and stimulated in vitro with Staphylococcus aureus Cowan I (SAC) plus IL-2. B cells proliferation, differentiation and IgM expression were analyzed by flow cytometry. B cell ATP release and involvement of P2 purinergic receptors in regulation of IgM secretion was assessed.

RESULTS

B cells cultured at 25 mM glucose in response to SAC stimulation released significantly less (≈ 55%) IgM comparing to cells maintained in 5mM glucose. Under resting and stimulatory conditions B cells released significant quantities of ATP to the culture media, but ATP level decreased when B cells were maintain in high glucose. SAC-induced B cell IgM release was totally blocked by highly selective antagonist (Az11645373) of P2X7 receptor. IgM secretion increased in the presence of potent P2X7 receptor agonist (BzATP), but this effect was abolished by high glucose concentration.

CONCLUSIONS/INTERPRETATION

High glucose concentration impairs B cell function by suppression of P2X7 receptor-dependent IgM release in response to in vitro bacterial antigen stimulation. This alteration may greatly contribute to the impaired humoral immune response in diabetics.

Trends in hospitalization for community-associated methicillin-resistant Staphylococcus aureus in New York City, 1997-2006: data from New York State's Statewide Planning and Research Cooperative System

OBJECTIVE

To describe trends in hospitalizations with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in New York City over 10 years and to explore the demographics and comorbidities of patients hospitalized with CA-MRSA infections.

DESIGN

Retrospective analysis of hospital discharges from New York State's Statewide Planning and Research Cooperative System database from 1997 to 2006.

PATIENTS

All patients greater than 1 year of age admitted to New York hospitals with diagnosis codes indicating MRSA who met the criteria for CA-MRSA on the basis of admission information and comorbidities.

METHODS

We determined hospitalization rates and compared demographics and comorbidities of patients hospitalized with CA-MRSA versus those hospitalized with all other non-MRSA diagnoses by multivariable logistic regression.

RESULTS

Of 18,226 hospitalizations with an MRSA diagnosis over 10 years, 3,579 (20%) were classified as community-associated. The CA-MRSA hospitalization rate increased from 1.47 to 10.65 per 100,000 people overall from 1997 to 2006. Relative to non-MRSA hospitalizations, men, children, Bronx and Manhattan residents, the homeless, patients with human immunodeficiency virus (HIV) infection, and persons with diabetes had higher adjusted odds of CA-MRSA hospitalization.

CONCLUSIONS

The CA-MRSA hospitalization rate appeared to increase between 1997 and 2006 in New York City, with residents of the Bronx and Manhattan, men, and persons with HIV infection or diabetes at increased odds of hospitalization with CA-MRSA. Further studies are needed to explore how changes in MRSA incidence, access to care, and other factors may have impacted these rates.

Arjunolic acid: beneficial role in type 1 diabetes and its associated organ pathophysiology

In this review article, we describe the most recent development of the beneficial effect of arjunolic acid (AA) in reducing type 1 diabetic pathophysiology. Diabetic mellitus is a serious and growing health problem worldwide. Increasing evidence suggest that oxidative stress plays a pivotal role in the pathogenesis of diabetes and its associated complications. Use of antioxidant supplements as a complimentary therapeutic approach in diabetes has, therefore, been seriously considered worldwide. AA, a natural pentacyclic triterpenoid saponin, is well known for various biological functions including antioxidant activity. It could prevent the increased production of ROS, RNS, AGEs, and the 8OHdG/2dG ratio and increase the intracellular antioxidant defence system. Signal transduction studies showed that AA could prevent hyperglycaemia induced activation of MAPKs, PKC, NF-κB signalling cascades and apoptotic cell death. Combining, AA supplements could be regarded as beneficial therapeutics in the treatment of diabetes and its associated complications.

Metabolic and clinical effects of the supplementation of a functional mixture of amino acids in cerebral hemorrhage

BACKGROUND

Oral supplementation of a specific mixture of essential and non-essential amino acids has been shown to modulate hypercatabolism in patients with chronic heart failure, leading to improved clinical outcome. The aim of this study was to test whether such effects could be replicated in an acute clinical model of hypercatabolism.

METHODS

After approval by the Ethics Committee, patients with acute brain hemorrhage admitted to the Neurosurgical ICU were randomly assigned to receive enterally for 14 days 20% of their estimated nitrogen requirements as a standard protein supplement (control group; n = 9) or as a functional amino acid mixture (Aminotrofic®, Errekappa Euroterapici; study group; n = 10). Metabolic and clinical outcome measures were monitored.

RESULTS

In the study group, insulin sensitivity and total lymphocyte count appeared to improve when compared with control patients. Less positive blood cultures were found in the study group against control patients (4 vs. 7, respectively; P = 0.05). Also, mortality in the study group was reduced than in control patients (60 vs. 77%; P = n.s.).

CONCLUSIONS

Supplementation with specific amino acids in critically ill patients may modulate metabolic response and improve clinical outcome.

Experimental diabetes attenuates calcium mobilization and proliferative response in splenic lymphocytes from mice

The present study was conducted to investigate the effects of the diabetic condition on cytosolic free Ca(2+) concentration, [Ca(2+)](i), and the proliferation of splenic lymphocytes from mice. Diabetes was induced in mice by intraperitoneal injection of alloxan. [Ca(2+)](i) and the proliferation ex vivo of splenic lymphocytes isolated from mice were examined using fura-2 and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide, respectively. Diabetes caused a significant increase in resting [Ca(2+)](i) and significantly reduced the ability of concanavalin A (Con A; a T-lymphocyte-selective mitogen) to increase [Ca(2+)](i), but not that of lipopolysaccharide (LPS; a B-lymphocyte-selective mitogen). In addition, diabetes significantly reduced Con A-stimulated but not LPS-stimulated lymphocyte proliferation. Verapamil (an L-type Ca(2+) channel blocker) inhibited Con A-induced increases in [Ca(2+)](i) and proliferation in lymphocytes from control and diabetic mice to a similar extent, respectively. These results suggest that diabetes attenuates Con A-stimulated T-lymphocyte proliferation by decreasing [Ca(2+)](i) via reduction of Ca(2+) entry through L-type Ca(2+) channels.

Possible involvement of stress hormones and hyperglycaemia in chronic mild stress-induced impairment of immune functions in diabetic mice

Stress, an important aspect of modern life, has long been associated with an altered homeostatic state. Little is known about the effect of the life stress on the outcome of diabetes mellitus, especially related to the higher risk of infections. Here, we evaluate the effects of chronic mild stress (CMS) exposure on the evolution of type I diabetes induced by streptozotocin administration in BALB/c mice. Exposure of diabetic mice to CMS resulted in a significant reduction of survival and a sustained increase in blood glucose values. Concerning the immune response, chronic stress had a differential effect in mice with diabetes with respect to controls, showing a marked decrease in both T- and B-cell proliferation. No correlation was found between splenic catecholamine or circulating corticosterone levels and the proliferative response. However, a significant negative correlation was found between glucose levels and concanavalin A- and lipopolysaccharide-stimulated proliferative responses of T and B cells. A positive correlation between blood glucose and splenic catecholamine concentrations was found in diabetic mice but not in controls subjected to CMS. Hence, the present report shows that diabetic mice show a worse performance in immune function after stress exposure, pointing to the importance of considering life stress as a risk factor for patients with diabetes.

Dysglycemia following glucocorticoid therapy for acute graft-versus-host disease adversely affects transplantation outcomes

Disordered glucose metabolism is a common complication of glucocorticoid therapy for acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic cell transplantation (HCT). We aimed to examine the impact of dysglycemia on outcomes in 173 recipients of HCT treated with glucocorticoids for aGVHD. A total of 147 of these patients contributed data to a landmark analysis performed at 12 weeks post-HCT. Median aGVHD onset was 21 days (range: 5-79) after transplant. Median duration of glucocorticoid therapy was 381 days (range: 15-1632). Glucose values were obtained from glucocorticoid initiation date to death or last follow-up, resulting in 11,588 total values. The median (range) for each parameter were: maximum 292 mg/dL (128-694), minimum 75 mg/dL (34-142), average 142 mg/dL (86-327), and standard deviation 46 mg/dL (12-108). Baseline diabetes mellitus predicted significantly greater maximum, mean, and standard deviation. With median follow-up of 20 months (range: 3-55), median overall survival (OS) was 33.7 months (95% confidence interval [CI] 16.4-not reached). On multivariable analysis, maximum, average, or standard deviation of glucose values predicted OS and maximum or average glucose values predicted nonrelapse mortality (NRM). Minimum glucose values of (0-60 mg/dL) were associated with worsened OS and increased NRM. Those patients treated with insulin or oral agents suffered significantly worse OS and increased NRM compared to patients who did not need therapy. Finally, those with sustained maximum values >200 mg/dL despite treatment suffered worse OS and increased NRM. These data suggest an independent adverse effect of dysglycemia in patients treated with glucocorticoids for aGVHD, and argue for stringent glycemic control in this setting.