Uncoupling hepatic insulin resistance - hepatic inflammation to improve insulin sensitivity and to prevent impaired metabolism-associated fatty liver disease in type 2 diabetes.

Diabetes mellitus is a metabolic disease clinically-characterized as acute and chronic hyperglycemia. It is emerging as one of the common conditions associated with incident liver disease in the US. The mechanism by which diabetes drives liver disease has become an intense topic of discussion and a highly sought-after therapeutic target. Insulin resistance (IR) appears early in the progression of type 2 diabetes (T2D), particularly in obese individuals. One of the co-morbid conditions of obesity-associated diabetes that is on the rise globally is referred to as non-alcoholic fatty liver disease (NAFLD). IR is one of a number of known and suspected mechanism that underlie the progression of NAFLD which concurrently exhibits hepatic inflammation, particularly enriched in cells of the innate arm of the immune system. In this review we focus on the known mechanisms that are suspected to play a role in the cause-effect relationship between hepatic IR and hepatic inflammation and its role in the progression of T2D-associated NAFLD. Uncoupling hepatic IR/hepatic inflammation may break an intra-hepatic vicious cycle, facilitating the attenuation or prevention of NAFLD with a concurrent restoration of physiologic glycemic control. As part of this review, we therefore also assess the potential of a number of existing and emerging therapeutic interventions that can target both conditions simultaneously as treatment options to break this cycle.

Improvement in insulin sensitivity and prevention of high fat diet-induced liver pathology using a CXCR2 antagonist.

BACKGROUND: Liver pathology (LP) characteristic of non-alcoholic fatty acid disease (NAFLD)/non-alcoholic steatohepatitis (NASH) is a prevalent co-morbidity of type 2 diabetes (T2D). Accumulating evidence indicates that neutrophils driving insulin resistance (IR), including hepatic IR, precipitate T2D-associated NAFLD/NASH. We hypothesized that targeting neutrophil accumulation into insulin-sensitive tissues in mice using a CXCR2 antagonist under T2D-precipitating high fat diet (HFD) could improve insulin sensitivity and prevent the progression towards liver pathology reminiscent of NAFLD/NASH. METHODS: Mice were age-matched and on standard rodent chow prior to 1:1 randomization into control and HFD formulated with the CXCR2 antagonist AZD5069 or with biologically inactive substitute. They were monitored for metabolic changes including insulin sensitivity using the hyperinsulinemic-euglycemic clamp and hepatic histopathologic evaluation in H&E-stained sections as well as via immunofluorescence microscopy of liver sections for leukocyte markers, collagen 1A1 formation, α-smooth muscle actin (SMA), and galectin-3 expression, for 16 weeks. Statistical tests used to determine significant differences among study groups and outcomes include Student's t-test, one-way ANOVA, repeated measures two-way ANOVA, and Fisher's exact test, depending on the analytical question. RESULTS: Compared to mice on HFD, mice in the AZD5069-formulated HFD exhibited improved insulin sensitivity, a modest reduction in weight gain, and a significant improvement in LP and markers related to NAFLD/NASH. Mice in the AZD5069-formulated HFD also exhibited reduced neutrophil accumulation into the liver at the end of the 16 week study period. CONCLUSIONS: These results show, for the first time, the effectiveness of a selective CXCR2 antagonist to improve insulin sensitivity, concomitantly preventing the progression towards LP characteristic of NAFLD/NASH. This represents a novel approach to target IR and developing LP under T2D-susceptible conditions using a single agent. Furthermore, our data extend the growing evidence in support of neutrophils as a leukocyte population that imprints and maintains a chronic inflammatory state in the progression of dysregulated metabolism in liver-specific co-morbid conditions.

Autoimmune Inflammation and Insulin Resistance: Hallmarks So Far and Yet So Close to Explain Diabetes Endotypes.

PURPOSE OF REVIEW: Diabetes mellitus can be categorized into two major variants, type 1 and type 2. A number of traits such as clinical phenotype, age at disease onset, genetic background, and underlying pathogenesis distinguish the two forms. RECENT FINDINGS: Recent evidence indicates that type 1 diabetes can be accompanied by insulin resistance and type 2 diabetes exhibits self-reactivity. These two previously unknown conditions can influence the progression and outcome of the disease. Unlike most conventional considerations, diabetes appears to consist of a spectrum of intermediate phenotypes that includes monogenic and polygenic loci linked to inflammatory processes including autoimmunity, beta cell impairment, and insulin resistance. Here we discuss why a shift of the classical bi-modal view of diabetes (autoimmune vs. non-autoimmune) is necessary in favor of a model of an immunological continuum of endotypes lying between the two extreme "insulin-resistant" and "autoimmune beta cell targeting," shaped by environmental and genetic factors which contribute to determine specific immune-conditioned outcomes.

Neutrophil-Associated Inflammatory Changes in the Pre-Diabetic Pancreas of Early-Age NOD Mice.

A growing body of evidence indicates that neutrophils are the first major leukocyte population accumulating inside the pancreas even before the onset of a lymphocytic-driven impairment of functional beta cells in type 1 diabetes mellitus (T1D). In humans, pancreata from T1D deceased donors exhibit significant neutrophil accumulation. We present a time course of previously unknown inflammatory changes that accompany neutrophil and neutrophil elastase accumulation in the pancreas of the non-obese diabetic (NOD) mouse strain as early as 2 weeks of age. We confirm earlier findings in NOD mice that neutrophils accumulate as early as 2 weeks of age. We also observe a concurrent increase in the expression of neutrophil elastase in this time period. We also detect components of neutrophil extracellular traps (NET) mainly in the exocrine tissue of the pancreas during this time as well as markers of vascular pathology as early as 2 weeks of age. Age- and sex-matched C57BL/6 mice do not exhibit these features inside the pancreas. When we treated NOD mice with inhibitors of myeloperoxidase and neutrophil elastase, two key effectors of activated neutrophil activity, alone or in combination, we were unable to prevent the progression to hyperglycemia in any manner different from untreated control mice. Our data confirm and add to the body of evidence demonstrating neutrophil accumulation inside the pancreas of mice genetically susceptible to T1D and also offer novel insights into additional pathologic mechanisms involving the pancreatic vasculature that have, until now, not been discovered inside the pancreata of these mice. However, inhibition of key neutrophil enzymes expressed in activated neutrophils could not prevent diabetes. These findings add to the body of data supporting a role for neutrophils in the establishment of early pathology inside the pancreas, independently of, and earlier from the time at onset of lymphocytic infiltration. However, they also suggest that inhibition of neutrophils alone, acting via myeloperoxidase and neutrophil elastase only, in the absence of other other effector cells, is insufficient to alter the natural course of autoimmune diabetes, at least in the NOD model of the disease.

Arrest in the Progression of Type 1 Diabetes at the Mid-Stage of Insulitic Autoimmunity Using an Autoantigen-Decorated All-trans Retinoic Acid and Transforming Growth Factor Beta-1 Single Microparticle Formulation.

Type 1 diabetes (T1D) is a disorder of impaired glucoregulation due to lymphocyte-driven pancreatic autoimmunity. Mobilizing dendritic cells (DC) in vivo to acquire tolerogenic activity is an attractive therapeutic approach as it results in multiple and overlapping immunosuppressive mechanisms. Delivery of agents that can achieve this, in the form of micro/nanoparticles, has successfully prevented a number of autoimmune conditions in vivo. Most of these formulations, however, do not establish multiple layers of immunoregulation. all-trans retinoic acid (RA) together with transforming growth factor beta 1 (TGFß1), in contrast, has been shown to promote such mechanisms. When delivered in separate nanoparticle vehicles, they successfully prevent the progression of early-onset T1D autoimmunity in vivo. Herein, we show that the approach can be simplified into a single microparticle formulation of RA + TGFß1 with surface decoration with the T1D-relevant insulin autoantigen. We show that the onset of hyperglycemia is prevented when administered into non-obese diabetic mice that are at the mid-stage of active islet-selective autoimmunity. Unexpectedly, the preventive effects do not seem to be mediated by increased numbers of regulatory T-lymphocytes inside the pancreatic lymph nodes, at least following acute administration of microparticles. Instead, we observed a mild increase in the frequency of regulatory B-lymphocytes inside the mesenteric lymph nodes. These data suggest additional and potentially-novel mechanisms that RA and TGFß1 could be modulating to prevent progression of mid-stage autoimmunity to overt T1D. Our data further strengthen the rationale to develop RA+TGFß1-based micro/nanoparticle "vaccines" as possible treatments of pre-symptomatic and new-onset T1D autoimmunity.

The Role of Genetic Variant rs13266634 in SLC30A8/ZnT8 in Postoperative Hyperglycemia After Major Abdominal Surgery.

CONTEXT: Following major surgery, postoperative hyperglycemia (POHG) is associated with suboptimal outcomes among patients with diabetes and nondiabetic patients. A specific genetic variant, rs13266634 (c.973C>T; p.ARG325TRP) in zinc transporter SLC30A8/ZnT8, is associated with protection against type 2 diabetes (T2D), suggesting it may be actionable for predicting and preventing POHG. OBJECTIVE: To determine independent and mediated influences of a genetic variant on POHG in patients undergoing a model major operation, complex ventral hernia repair (cVHR). PATIENTS AND DESIGN: For 110 patients (mean body mass index, 34.9 ± 5.8; T2D history, 28%) undergoing cVHR at a tertiary referral center (January 2012 to March 2017), multivariable regression was used to correlate the rs13266634 variant to preoperative clinical, laboratory, and imaging-based indices of liver steatosis and central abdominal adiposity to POHG. Causal mediation analysis (CMA) was used to determine direct and mediated contributions of SLC30A8/ZnT8 status to POHG. RESULTS: Variant rs13266634 was present in 61 patients (55.4%). In univariate models, when compared with patients with homozygous wild-type genotype (C/C, n = 49), rs13266634 was associated with significantly lower risks of POHG (OR, 0.30; 95% CI, 0.14 to 0.67; P = 0.0038). Multivariable regression indicated that the association was independent (OR, 0.39; 95% CI, 0.15 to 0.97; P = 0.040). Additionally, CMA suggested that rs13266634 protects against POHG directly and indirectly through its influence on liver steatosis and central adiposity. CONCLUSIONS: In medically complex patients undergoing major operations, the rs13266634 variant protects against POHG and its associated outcomes, through independent and mediated contributions. In C/C patients undergoing major operations, SLC30A8/ZnT8 may prove useful to stratify the risk of POHG and potentially as a therapeutic target.

The Sex-specific Effects of LPS on Depressive-like Behavior and Oxidative Stress in the Hippocampus of the Mouse.

Many human and animal studies have implicated inflammation as a mediator of oxidative stress and a possible contributor to hippocampal atrophy in the pathophysiology of major depressive disorder. We aimed to examine the effect of peripheral, systemic inflammation on oxidative stress and apoptosis in the hippocampi of male and female mice. We hypothesized that (1) lipopolysaccharide (LPS) would induce depressive-like behavior and hippocampal oxidative stress after 1 day in males, and (2) that a single LPS exposure would result in hippocampal apoptosis at 28 days. Further, we predicted that female sex would confer protection from the molecular and behavioral deleterious effects of LPS. Males exhibited depressive-like behavior 24 h after LPS administration compared to the males given saline. Female mice did not exhibit depressive-like behavior after LPS compared to females in the saline group. Males given LPS also had increased levels of superoxide dismutase (SOD) I in the hippocampus by 24 h compared to the saline group. At 28 days, we found decreased levels of brain derived neurotrophic factor (BDNF) protein in males given LPS compared to males given saline. Moreover, males given LPS showed increased apoptosis. Our work will provide insight into the underlying biology in males and females with MDD, and potentially underlying differences between the sexes. Also, our work will hopefully inform optimal clinical treatments that may indeed differ between the sexes.

Salivary cotinine levels in children with otolaryngological disorders.

OBJECTIVE: To determine if salivary cotinine, a biomarker for tobacco smoke exposure, is elevated more often or to a higher degree in children meeting criteria for tonsillectomy or tympanostomy tube insertion. METHODS: Saliva samples were obtained from 3 groups of children for salivary cotinine measurement. Group 1 served as healthy controls. Group 2 consisted of subjects meeting tympanostomy tube criteria. Group 3 consisted of patients meeting tonsillectomy criteria. Environmental tobacco smoke (ETS) exposure was defined as a salivary cotinine concentration ≥1.0 ng/mL. Demographic data, smoke exposure history, and co-morbidities were also determined. RESULTS: 331 patients were included, with 112 in Group 1, 111 in Group 2, and 108 in Group 3. No differences were encountered for smoke exposure by history or smoker's identity, salivary cotinine level, or frequency of positive cotinine results. 42.6% of Group 1 had positive salivary cotinine compared to 51.8% of Group 2 and 47.7% of Group 3. Group 1 had a mean salivary cotinine level of 2.42 ng/mL compared to 2.54 ng/mL in Group 2 and 2.60 ng/mL in Group 3. The frequency of positive cotinine levels was higher than expected based on parental history. Among subjects with positive cotinine levels, 93 had no ETS exposure, and 64 had ETS exposure by history. CONCLUSION: Approximately 50% of children who undergo tonsillectomy and tympanostomy tube insertion have objective evidence of ETS exposure. Parental history underestimates passive smoke exposure, which can impact perioperative care.

Immune and metabolic responses in early and late sepsis during mild dietary zinc restriction.

BACKGROUND: Mild dietary zinc (Zn) deficiency is widespread in human populations, but its influence on recovery after acute illness is poorly understood. In a mouse model of abdominal sepsis (cecal ligation puncture), systemic immune responses and liver metabolism were monitored in early (24 h) and late (5 d) phases, under control conditions and during mild dietary Zn restriction. METHODS: Mice were fed diets adequate or marginally deficient (ZM) in Zn (30 versus 10 mg zinc/kg diet) for 4 wk, before undergoing laparotomy alone (nonseptic control) or cecal ligation puncture (septic). RESULTS: Among nonseptic mice, the ZM state was not associated with differences in inflammation or metabolic responses. Among septic mice, mortality did not differ between the zinc adequate and ZM groups. In the early phase, the ZM state amplified increases in plasma interleukin (IL) 6, tumor necrosis factor alpha, and IL-10, while dampening the interferon gamma response. In the late phase, subtle but significant ZM-associated increases were observed in plasma IL-5 and interferon gamma levels and hepatic protein synthesis, the latter of which appeared to be mammalian target of rapamycin independent and was associated with increased hepatic tumor necrosis factor alpha messenger RNA content. CONCLUSIONS: Without increasing mortality, the ZM state is associated with a more disordered acute systemic inflammatory response and persistence or enhancement of acute phase responses within the liver parenchyma.

Oral omega-3 fatty acids promote resolution in chemical peritonitis.

BACKGROUND: Recent studies suggest that purified omega-3 fatty acids may attenuate acute inflammation and hasten the transition to healing. In this study, we tested the hypothesis that pretreatment with omega-3-rich fish oil (FO) would promote resolution of peritoneal inflammation through production of specific lipid mediators. METHODS: C57/BL6 mice were given a daily 200-µL oral gavage of saline (CTL) or FO (1.0-1.5 g/kg/d docosahexaenoic acid and 1.3-2.0 g/kg/d eicosapentaenoic acid) for 7 d before chemical peritonitis was induced with thioglycollate. Peritoneal lavage fluid was collected before induction and at days 2 and 4 after peritonitis onset. Prostaglandin E2 (PGE2), Leukotriene B4 (LTB4), Resolvin D1 (RvD1), and the composition of immune cell populations were examined in peritoneal lavage exudates. Cells harvested from the peritoneum were assessed for macrophage differentiation markers, phagocytosis, and lipopolysaccharide-induced cytokine secretion profiles (interleukin [IL]-6, IL-10, IL-1ß, TNFα). RESULTS: The ratio of RvD1 to pro-inflammatory PGE2 and LTB4 was increased in the peritoneal cavity of FO-supplemented animals. FO induced a decrease in the number of monocytes in the lavage fluid, with no change in the number of macrophages, neutrophils, or lymphocytes. Macrophage phagocytosis and M1/M2 messenger RNA markers were unchanged by FO with the exception of decreased PPARγ expression. FO increased ex vivo TNFα secretion after stimulation with lipopolysaccharide. CONCLUSIONS: Our findings provide evidence that nutraceutically relevant doses of FO supplements given before and during chemical peritonitis shift the balance of lipid mediators towards a proresolution, anti-inflammatory state without drastically altering the number or phenotype of local innate immune cell populations.

Sarcopenia and sarcopenic obesity in patients with complex abdominal wall hernias.

BACKGROUND: Chronic muscle wasting, or sarcopenia, has been associated with poor-health outcomes after major surgical procedures. Here, we explore the utility of CT-generated determinations of sarcopenia as markers of risk in patients undergoing evaluation for complex ventral hernia repair. METHODS: In 148 successive patients being evaluated for complex ventral hernia repair, CT scans were analyzed retrospectively for attributes of the hernia and indices of core-muscle mass, correlating them with preoperative clinical/laboratory profiles and outcomes in 82 patients who had undergone surgery. RESULTS: Prevalence of sarcopenia, and sarcopenia corrected for obesity, was 26% and 20% respectively. Sarcopenia was associated with age, some laboratory indicators, and increased hospital length of stay but not with a higher likelihood of surgical site occurrence. CONCLUSIONS: Obesity may obscure the value of sarcopenia as a marker of metabolic disturbance and postoperative outcome. Image-based measurements of core-muscle mass should be used with caution as predictors of risk in similar surgical populations.

Impaired recovery from peritoneal inflammation in a mouse model of mild dietary zinc restriction.

SCOPE: Mild dietary zinc (Zn) deficiency is wide-spread in human populations, but the effect on Zn-dependent processes of immune function and healing are not well understood. The consequences of mild dietary Zn restriction were examined in two mouse models of inflammation and recovery. METHODS AND RESULTS: Male C57BL/6 mice were fed a Zn adequate diet (ZA, 30 mg Zn/kg diet), or diets containing sub-optimal Zn levels (ZM, 15 mg Zn/kg diet; ZD, 10 mg Zn/kg diet) for 30 days before a thioglycollate peritonitis challenge. Plasma lipid profiles were distinct, with greater Zn restriction resulting in a greater impact on metabolites. The milder ZM diet was selected for immune studies. Peritoneal macrophages from ZM mice displayed increased phagocytosis and amplified pro-inflammatory cytokine (IL-1ß, IL-6, and TNFα) release compared to ZA, at baseline and after a secondary LPS challenge. Splenocytes isolated from ZM mice displayed an increase in IL-6 and a reduction in anti-inflammatory IL-4 compared to ZA. Cytokine levels in plasma were unaltered. Following mechanical manipulation of the intestines to induce ileus, ZM mice had delayed intestinal transit compared to ZA. CONCLUSION: Mild Zn deficiency enhances local inflammatory responses, amplifying macrophage functions and delaying recovery from acute insults within the peritoneum.

Peri-procedural povidone-iodine rectal preparation reduces microorganism counts and infectious complications following ultrasound-guided needle biopsy of the prostate.

PURPOSE: The purpose of the study was to evaluate whether a peri-procedural povidone-iodine rectal preparation (PIRP) prior to transrectal ultrasound-guided prostate needle biopsy (TRUS PNB) can reduce microorganism colony counts and infectious complications. METHODS: Our institutional TRUS PNB database was reviewed to identify infectious post-biopsy complications (defined as fever >38.5 °C with positive culture). The last 570 biopsy patients were divided into those administered only preoperative oral and/or parenteral antibiotics (n = 456; chronologically cohorts A-D) versus men receiving peri-procedural PIRP in conjunction with standard preoperative antibiotics (n = 114; cohort E). Rectal cultures were obtained in the PIRP cohort to quantify changes in microorganism colony counts. RESULTS: Mean baseline PSA for patients was 11.6 ng/ml, 63 % were undergoing an initial biopsy, and 17 % had documented use of antibiotic therapy within the previous 6 months. A reduction in infectious complications was observed when comparing the conventional antibiotic (cohorts A-D) versus PIRP (cohort E) group (1.8 vs. 0 %), with the largest magnitude of decline occurring in the concurrent contemporary cohorts (cohort D-5.3 % vs. cohort E-0 %, p = 0.03). Rectal cultures obtained in 92 men before and after PIRP administration noted a 97 % reduction in microorganism colonies (2.1 × 10(5) vs. 6.3 × 10(3) CFU/ml, p < 0.001). No adverse reactions to the PIRP were reported by patients 7 days post-biopsy. CONCLUSIONS: Peri-procedural PIRP decreased microorganism colony counts and effectively reduced infectious complications following TRUS PNB. This safe, cheap, and simple strategy may be a reasonable alternative to systemic or targeted antibiotic therapy to reduce post-biopsy infections.

Prevalence of systemic inflammation and micronutrient imbalance in patients with complex abdominal hernias.

OBJECTIVE: To determine the prevalence of low-grade inflammation, micronutrient imbalances and associated clinical profiles in patients being evaluated for complex abdominal hernia repair. METHODS: Review of 127 consecutive adult patients for evaluation of complex ventral hernias from January 2012 to March 2013. Records were analyzed to determine the prevalence and correlations of clinical risk factors, attributes of hernias identified by computerized tomography, and laboratory indices of metabolism, inflammation and micronutrient imbalances. RESULTS: Strong correlations (p < 0.001) were established for body mass index (BMI) with volume of hernia content and C-reactive protein (CRP) level. CRP levels correlated strongly with red cell distribution width and inversely with zinc (p < 0.01). Evidence of micronutrient imbalance (abnormal zinc or red cell distribution width [RDW]) was observed in 48%. CONCLUSIONS: In this comorbidity-rich population with known variability in surgical outcomes, the prevalence of chronic inflammation and micronutrient deficiency are high enough to warrant systemic preoperative evaluation given their possible effect on wound healing and convalescence. Simple repletion is unlikely to improve outcomes without attention to the biological stresses that are associated with micronutrient imbalance.

FoxO6 integrates insulin signaling with gluconeogenesis in the liver.

OBJECTIVE: Excessive endogenous glucose production contributes to fasting hyperglycemia in diabetes. This effect stems from inept insulin suppression of hepatic gluconeogenesis. To understand the underlying mechanisms, we studied the ability of forkhead box O6 (FoxO6) to mediate insulin action on hepatic gluconeogenesis and its contribution to glucose metabolism. RESEARCH DESIGN AND METHODS: We characterized FoxO6 in glucose metabolism in cultured hepatocytes and in rodent models of dietary obesity, insulin resistance, or insulin-deficient diabetes. We determined the effect of FoxO6 on hepatic gluconeogenesis in genetically modified mice with FoxO6 gain- versus loss-of-function and in diabetic db/db mice with selective FoxO6 ablation in the liver. RESULTS: FoxO6 integrates insulin signaling to hepatic gluconeogenesis. In mice, elevated FoxO6 activity in the liver augments gluconeogenesis, raising fasting blood glucose levels, and hepatic FoxO6 depletion suppresses gluconeogenesis, resulting in fasting hypoglycemia. FoxO6 stimulates gluconeogenesis, which is counteracted by insulin. Insulin inhibits FoxO6 activity via a distinct mechanism by inducing its phosphorylation and disabling its transcriptional activity, without altering its subcellular distribution in hepatocytes. FoxO6 becomes deregulated in the insulin-resistant liver, accounting for its unbridled activity in promoting gluconeogenesis and correlating with the pathogenesis of fasting hyperglycemia in diabetes. These metabolic abnormalities, along with fasting hyperglycemia, are reversible by selective inhibition of hepatic FoxO6 activity in diabetic mice. CONCLUSIONS: Our data uncover a FoxO6-dependent pathway by which the liver orchestrates insulin regulation of gluconeogenesis, providing the proof-of-concept that selective FoxO6 inhibition is beneficial for curbing excessive hepatic glucose production and improving glycemic control in diabetes.

Immunotherapy-based strategies for the treatment of autoimmune diabetes: searching for the cure.

Type 1 Diabetes is an autoimmune disease most often associated with elevated and uncontrolled blood glucose levels. Therefore patient education and treatment compliance is often focused on disease maintenance through insulin treatment and blood glucose control. Unfortunately insulin therapy alone does not prevent the formation of diabetic complications. In order to find a real cure, the underlying pathology of the disease must be directly addressed. Diabetes is caused by the initial rapid destruction of the insulin producing beta cells of the pancreas by autoreactive T-cells. The autoimmune process is also maintained through dendritic cell auto-antigen presentation and the production of autoantibodies by B cells. Only through some forms of immunotherapy can the immune system be rebalanced to assure the survival of the remaining beta cell population. These techniques include cell ablation, competitive decoy auto-antigens, reduced cell activation, and auto-antigen introduction. Here we will review the current state of these different technologies and their progression through clinical trials for the treatment of type 1 diabetes.

A peptide-based material platform for displaying antibodies to engage T cells.

This study investigated a strategy by which antibodies are displayed to engage T cells. A peptide composite containing binding sites was characterized in vitro and explored as an injectable system in vivo. The composite consists of two amphiphilic peptides, AEAEAKAKAEAEAKAK (referred to as "EAK") and EAK appended with six consecutive histidines at the C-terminus ("EAKH6"). Spectroscopic analysis showed the two peptides integrated into a single structure. Prior to combination, conformational analysis revealed that EAKH6 adopts a mixed α-helix/ß-strand conformation. In the presence of EAK, EAKH6 exists predominately in ß-strand conformation. The composite of EAK-EAKH6 was found to display His-tags, using nickel-bound horseradish peroxidase as a probe. T cell-specific antibodies were found stably displayed on the EAK-EAKH6 assembly using recombinant protein A/G and anti-histidines antibody as an adaptor. When mounted with anti-CD4 antibody, the system was shown to capture CD4T cells in a mixed population of lymphocytes. Antibodies were concentrated in the subcutaneous space in mice when co-administered with EAK and EAKH6 along with protein A/G and anti-histidines antibody as a solution. We report here the use of amphiphilic peptides to display Ab in vivo, the results indicating that the design can be used as a platform for engaging specific subsets of leukocytes for the purpose of immune modulation.

Drug delivery technologies for autoimmune disease.

IMPORTANCE OF THE FIELD: Targeting autoimmune disease poses two main challenges. The first is to identify unique targets to suppress directly or indirectly autoreactive cells exclusively. The second is to penetrate target tissues to deliver specifically drugs to desired cells that can achieve a therapeutic outcome. AREAS COVERED IN THIS REVIEW: Herein, the range of drug delivery methods available and under development and how they can be useful to treat autoimmune diseases are discussed. Polymer delivery methods, as well as biological methods that include fusion proteins, targeted antibodies, recombinant viruses and cell products are compared. WHAT THE READER WILL GAIN: Readers will gain insight into the progression of clinical trials for different technologies and drug delivery methods useful for targeting and modulating the function of autoreactive immune cells. TAKE HOME MESSAGE: Several tissue-specific polymer-based and biologic drug delivery systems are now in Phase II/III clinical trials. Although these trials are focused mainly on cancer treatment, lessons from these trials can guide the use of the same agents for autoimmunity therapeutics.

Identification of a cardiac specific protein transduction domain by in vivo biopanning using a M13 phage peptide display library in mice.

BACKGROUND: A peptide able to transduce cardiac tissue specifically, delivering cargoes to the heart, would be of significant therapeutic potential for delivery of small molecules, proteins and nucleic acids. In order to identify peptide(s) able to transduce heart tissue, biopanning was performed in cell culture and in vivo with a M13 phage peptide display library. METHODS AND RESULTS: A cardiomyoblast cell line, H9C2, was incubated with a M13 phage 12 amino acid peptide display library. Internalized phage was recovered, amplified and then subjected to a total of three rounds of in vivo biopanning where infectious phage was isolated from cardiac tissue following intravenous injection. After the third round, 60% of sequenced plaques carried the peptide sequence APWHLSSQYSRT, termed cardiac targeting peptide (CTP). We demonstrate that CTP was able to transduce cardiomyocytes functionally in culture in a concentration and cell-type dependent manner. Mice injected with CTP showed significant transduction of heart tissue with minimal uptake by lung and kidney capillaries, and no uptake in liver, skeletal muscle, spleen or brain. The level of heart transduction by CTP also was greater than with a cationic transduction domain. CONCLUSIONS: Biopanning using a peptide phage display library identified a peptide able to transduce heart tissue in vivo efficiently and specifically. CTP could be used to deliver therapeutic peptides, proteins and nucleic acid specifically to the heart.

Dendritic cell mediated therapy for immunoregulation of type 1 diabetes mellitus.

Diabetes is a state of imbalance in insulin secretion and tissue sensitivity resulting in hyperglycemia and a host of other metabolic changes. Increased patient morbidity and mortality are caused in part by diabetic complications that include cardio-vascular complications, retinopathy, neuropathy, and nephropathy (1). The early onset of disease in type 1 diabetes mellitus increases the effects of these complications since the risk of development increases with disease duration. Clinical agents are currently available for type 2 diabetic patients to increase both secretion and sensitivity to insulin. These compounds are ineffective in type 1 diabetic patients due to the destruction of the insulin producing beta cells in the pancreatic islets of Langerhans, making type 1 and non-responsive type 2 diabetic patients dependent on insulin replacement therapy. Intensive insulin treatment delays onset of these complications, but does not eliminate them (1). Insulin replacement therapy is not a cure for type 1 diabetes; to establish a cure, the destruction of the beta cells themselves must be directly addressed. Here we will focus on immunoregulatory techniques to prevent beta cell loss due to the autoimmunity found in type 1 diabetes mellitus.