Preparation of PLGA Microspheres Using the Non-Toxic Glycofurol as Polymer Solvent by a Modified Phase Inversion Methodology.

Poly(D,L-lactide-co-glycolide is a biodegradable copolymer that can release pharmaceuticals. These pharmaceuticals can provide local therapy and also avert the clinical issues that occur when a drug must be given continuously and/or automatically. However, the drawbacks of using poly(D,L-lactide-co-glycolide include the kinetics and duration of time of poly(D,L-lactide-co-glycolide drug release, the denaturing of the drug loaded drug, and the potential clinical side effects. These drawbacks are mainly caused by the volatile organic solvents needed to prepare poly(D,L-lactide-co-glycolide spheres. Using the non-toxic solvent glycofurol solvent instead of volatile organic solvents to construct poly(D,L-lactide-co-glycolide microspheres may deter the issues of using volatile organic solvents. Up to now, preparation of such glycofurol spheres has previously met with limited success. We constructed dexamethasone laden poly(D,L-lactide-co-glycolide microspheres utilizing glycofurol as the solvent within a modified phase inversion methodology. These prepared microspheres have a higher drug load and a lower rate of water diffusion. This prolongs drug release compared to dichloromethane constructed spheres. The glycofurol-generated spheres are also not toxic to target cells as is the case for dichloromethane-constructed spheres. Further, glycofurol-constructed spheres do not denature the dexamethasone molecule and have kinetics of drug release that are more clinically advantageous, including a lower drug burst and a prolonged drug release.

Characterization of a mouse model of islet transplantation using MIN-6 cells.

Immortalized beta cells are an abundant source of insulin-producing cells. Although MIN-6 cells have similar characteristics as normal islets in vitro, the in vivo use of MIN-6 cells has not been fully described. This study characterizes in vivo mouse models of MIN-6 transplantation and rejection. Subcutaneous (sc) transplantation of MIN-6 cells in either Matrigel or HyStem-C hydrogels reduced blood sugars in nude mice and thus are good matrices for MIN-6 cells in vivo. NOD mice are good transplant recipients since they best rejected MIN-6 cells. MLR responses from BalbC, Black Webster, Swiss Black, C3H, and NOD mice correlated with mean blood glucose response suggesting the importance of allogeneic differences in the rejection of cells. Three days of cyclosporine administration caused no inhibition of MIN-6 cell rejection and 6 days resulted in a transient decrease in blood glucose, while daily administration inhibited rejection long term. Kinetic glucose tolerance (GTT) studies in nude mice demonstrated transplanted MIN-6 cells are close but not as effective as normal islets in controlling blood glucose and blood glucose set point for insulin release in MIN-6 cells decreases to hypoglycemic levels over time. To avoid hypoglycemia, the effect of MIN-6 cell irradiation was assessed. However, irradiation only delayed the development of hypoglycemia, not altering the final glucose set point for insulin release. In conclusion, we have characterized a mouse model for beta-cell transplantation using subcutaneous MIN-6 cells that can be used as a tool to study approaches to mitigate immune rejection.

The Role of Type I Interferon Subtypes and Interferon-Gamma in Type I Interferon Diabetes Inhibitory Activity in the NOD Mouse.

As in bacterial infections and endotoxin shock, type I interferons (IFNs) also have complex and often opposing effects in various models of autoimmune disease. We have shown that type I IFN paradoxically inhibits autoimmune diabetes in the nonobese diabetic mouse (NOD) and biobreeding (BB) rat. We hypothesize that type I IFN activity differs by IFN subtype and interaction with IFN-gamma. We examined the structure-function relationship of the type I IFN molecule and the mechanism of its diabetes-sparing activity in the NOD mouse. While both recombinant human IFN-alpha A/D (bgl 11) (rHuIFN-alphaA/D) and ovine IFN-tauImod (ovIFN-tau) potently inhibited the development of diabetes (P < 0.01), neither recombinant human IFN-alpha B/D (rHuIFN-alphaB/D) nor recombinant human IFN-alpha consensus (CIFN) were efficacious. The activity of IFN subtypes correlate with their NH3-terminal amino acid sequences. All type I IFN save CIFN, which has no diabetes-sparing activity, inhibited the accessory cell function. IFN-tau administration decreased the expression of Fas and ICAM on total cells, class II MHC expression on B cells, and CD40L expression on T cells by 39%, 45%, 45%, and 60%, respectively. In addition, IFN-tau inhibited the development of diabetes in the NOD.IL4(null) but not the NOD.IFN-gamma(null) mice, suggesting a coordinated interaction between type I and type II IFNs to suppress diabetes development. Thus, the amino terminal portion of the type I IFN molecule influences its ability to inhibit the development of autoimmune diabetes in NOD mice. These data also support the contention that IFN-gamma may have a role in mediating the diabetes-sparing effect of high-dose type I IFNs by the inhibition of the IFN-gamma-inducible immune modulators, class II MHC, Fas, ICAM, and CD40L.

Parenting goals: predictors of parent involvement in disease management of children with type 1 diabetes.

The purpose of this study was to develop a measure of diabetes-specific parenting goals for parents of children with type 1 diabetes and to examine whether parenting goals predict a change in parenting involvement in disease management. An independent sample of primary caretakers of 87 children aged 10 to 16 years with type 1 diabetes completed the measure of parenting goals (diabetes-specific and general goals); both parent and child completed measures of parent responsibility for diabetes management at baseline and 6 months. Parents ranked diabetes-specific parenting goals as more important than general parenting goals, and rankings were moderately stable over time. Parenting goals were related to parent responsibility for diabetes management. The relative ranking of diabetes-specific parenting goals predicted changes in parent involvement over 6 months, with baseline ranking of goals predicting more parental involvement at follow-up. Parenting goals may play an important role in family management of type 1 diabetes.

Cyclosporin and methotrexate therapy induces remission in type 1 diabetes mellitus.

Cyclosporin and methotrexate administration induces remission of type 1 diabetes mellitus. Administration of high-dose cyclosporin (cyclo) has been demonstrated to induce remission of type 1 diabetes mellitus (T1D). Its usefulness was limited by its toxicity. Since methotrexate (mtx) and cyclo synergistically inhibit autoimmune processes, we postulated that low doses of cyclo and mtx could safely induce remission of T1D. In a pilot study, insulin dose requirements and glycemic control were compared in 10 new onset T1D control children with seven children who were administered cyclo at 7.5 mg/kg/day for 6 weeks and then 4 mg/kg/day in addition to mtx 5 mg/kg/wk for 1 year. After 6 weeks, cyclo doses were adjusted to maintain blood cyclo levels 110-220 ng/ml. All children were treated with two daily injections of insulin. Clinical and biochemical toxicity of drug therapy was assessed. There were only very minor adverse effects and no drug induced biochemical test abnormalities. Mean HbA1c levels were similar in the experimental and control groups at baseline and at 3, 6, and 9 months but was lower in the cyclo + mtx group at 12 months. Daily insulin requirements of the groups were similar at baseline but lower in the cyclo + mtx group at 3, 6, 9, and 12 months. Although no control subjects became non-insulin requiring, four of seven cyclo + mtx-treated subjects were entirely off insulin therapy for 2.5, 4.5, 8, and 12 months. Low-dose cyclo and mtx treatment of subjects with new onset T1D can safely induce remission of disease and decrease the amount of required insulin.

Assessment of an illness-specific dimension of self-esteem in youths with type 1 diabetes.

OBJECTIVE: The initial validation of a brief assessment of a diabetes-specific self-esteem dimension in adolescents with type 1 diabetes. METHODS: Youths with type 1 diabetes (n = 87) aged 10-16 years were administered the multidimensional Self-Esteem Questionnaire (SEQ) and a newly designed assessment of diabetes-specific self-esteem (DSSE). Their parents completed parallel forms. Adherence to the diabetes regimen and glycemic control were also assessed. RESULTS: In factor analysis, DSSE items formed a distinct dimension of self-esteem in addition to the SEQ dimensions. This factor uniquely contributed to differences in youths' global self-esteem. Significant associations with adherence and glycemic control suggested its concurrent validity. Agreement between youth- and parent-report DSSE forms supported inter-rater reliability. CONCLUSIONS: The findings provide preliminary support for recognizing the importance of a DSSE dimension in adolescents' adjustment to diabetes, and for the reliability and validity of the proposed assessment strategy.

Interferon-tau inhibits the development of diabetes in NOD mice.

Interferon-alpha (IFN-alpha) inhibits the development of diabetes in animal models of autoimmune diabetes. However, the mechanism of the action is not fully understood and drug toxicity could limit its potential clinical utility. Interferon-tau (IFN-tau) is another type 1 interferon, which has less toxicity but may have different biologic activity than IFN-alpha. This study explores the effect of IFN-tau on the diabetic process in non-obese diabetic (NOD) mice. IFN-tau by intraperitoneal, subcutaneous, or oral routes of administration decreased the development of spontaneous diabetes in NOD mice. Islet inflammation was decreased 50%. IFN-tau administration to recipient mice prevented the development of passively transferred and cyclophosphamide accelerated diabetes. IFN-tau treatment also decreased anti-islet effector activity of NOD splenic cells. Immunoregulatory activity of splenic cells was augmented by IFN-tau administration as was the number of splenic CD25+CD4+ cells. Concanavalin A (Con A)-induced release of IFN-gamma was decreased in spleen cells from IFN-tau treated mice. In conclusion, IFN-tau inhibits spontaneous autoimmune diabetes and passively transferred diabetes in the NOD mouse. This diabetes sparing activity may be due to an induction of regulatory cells, possibly CD25+CD4+ T cells, which in turn inhibit anti-islet effector cell activity and the development of insulitis and diabetes. Due to the lower drug toxicity, IFN-tau could be a better drug candidate than IFN-alpha for experimental clinical trials.

Identification of distinct self-management styles of adolescents with type 1 diabetes.

OBJECTIVE: Using a profile-based approach to the assessment of diabetes management, the purpose of this study was to identify and evaluate an empirically derived classification system of distinct self-management styles. RESEARCH DESIGN AND METHODS: Youth with type 1 diabetes (n = 156) aged 10-16 years and their parents were administered a modified version of the Diabetes Self-Management Profile (DSMP). Cluster analyses were performed independently on parent and youth report forms to categorize patients based on their patterns of scores in five diabetes self-management areas. RESULTS: Cluster analyses revealed three self-management styles that emerged from both youth and parent report: a "methodical style" (33%) with an emphasis on careful meal planning and correct insulin administration; an "adaptive style" (46%), characterized by high rates of blood glucose testing, exercise, and self-care adjustments; and an "inadequate style" (21%) with moderate rates of self-care adjustments and otherwise low DSMP scores. Convergence between parent and youth report classifications was moderate (Cohen's kappa = 0.47, P < 0.0001). A1C was 1.6% higher in the inadequate style group than in both other groups (P < 0.0001), and the classification significantly accounted for differences in A1C above what was explained by an overall DSMP score. CONCLUSIONS: The findings provide support for recognizing subgroups of patients with unique multidimensional patterns of self-care behaviors. The assessment of self-management styles may prove useful for customized treatments that are targeted directly to the patients' needs.

Assessing regimen adherence of adolescents with type 1 diabetes.

OBJECTIVE: The purpose of this study is to evaluate two updated measures of diabetes regimen adherence. The Diabetes Self-Management Profile (DSMP) is a widely used, structured interview. Limitations include a substantial interviewer and respondent time burden and the need for well-trained interviewers to use appropriate prompts and score the open-ended responses. The Diabetes Behavior Rating Scale (DBRS) is a self-administered, fixed-choice survey. RESEARCH DESIGN AND METHODS: Both measures were administered to 146 youth with type 1 diabetes (aged 11-18 years) and their parents. Items were added to the DBRS to allow for both flexible and conventional regimens, and the DSMP was modified to use standardized wording across items, accommodate flexible regimens, and permit administration by nonmedical interviewers. RESULTS: Both measures had good evidence of internal consistency (for the DSMP: parent 0.75 and youth 0.70; for the DBRS: parent 0.84 and youth 0.84). Scores on the DSMP and the DBRS were significantly related (r = 0.72 for parents and 0.74 for youth). There was moderate agreement between parent and youth (DSMP, r = 0.51; DBRS, r = 0.48). The measures were correlated with HbA1c for both parent (DSMP, r = -0.35; DBRS, r = -0.35) and youth (DSMP, r = -0.36; DBRS, r = -0.34) reports. CONCLUSIONS: Both measures exhibit good psychometric properties and good criterion validity but varied in terms of respondent and interviewer burden, issues that should be considered in selecting assessment procedures.

Characterization of anti-islet cytotoxic human T-cell clones from patients with type 1 diabetes mellitus.

To identify important anti-islet T-cells and their target antigen(s), we have isolated and characterized seventeen human T-cell clones which are reactive to an extract of rat insulinoma (RIN) cells from three children with new onset type 1 diabetes mellitus (T1D). Of these 17 clones, 15 were found tissue specific. Six of eight tested tissue specific clones did not recognize known islet antigens such as GAD, 52 kDa islet protein, insulin, ICA512, and heat shock protein 60 (hsp60), suggesting that these clones recognize an autoantigen not previously identified. All tested clones were phenotypically CD4 and functionally Th0 or Th0/Th1 cells. One RIN extract reactive clone (2E9) recognized hsp60 and was CD4 and TCR alpha/beta positive. This clone also proliferated in response to human and rat islets suggesting that the antigen is conserved between species. This clone and 75% of all the tested RIN reactive clones exhibited anti-islet cytotoxicity by lysing target cells coated with RIN extract. HLA DR determinants may play a role in this cytotoxic activity since preincubation with HLA DR antibody decreased the anti-islet cytoxicity of the two tested clones. In conclusion, we have isolated RIN reactive CD4+T-cell clones from diabetic subjects, six of which appears tissue specific and non-reactive to putative important islet antigens, and in turn may be recognizing yet undiscovered islet antigens. The high frequency anti-islet cytotoxic properties of the islet reactive clones provides evidence for a role of CD4+ cytotoxic T-lymphocytes in the diabetic process. Further, the isolation of hsp60 reactive clone with anti-islet cytotoxic properties suggests that cell mediated immunity against hsp60 may be important in the pathogenesis of diabetes.

Self-efficacy, outcome expectations, and diabetes self-management in adolescents with type 1 diabetes.

The goal of this research was to develop and evaluate measures of adolescent diabetes management self-efficacy and outcome expectations that reflect developmentally relevant, situation-specific challenges to current diabetes regimens. Self-efficacy for diabetes management, expected outcomes of adherence, adherence to the diabetes regimen, and glycemic control were assessed in 168 adolescents (ages 10-16 years) with type 1 diabetes. Factor analyses indicated a single scale for self-efficacy and two distinct factors representing positive and negative outcome expectations. Reliability and predictive validity of the new scales were supported. In regression analyses, self-efficacy and the interaction of self-efficacy with expectations of positive outcomes were significantly associated with diabetes self-management adherence and glycemic control in older adolescents. The effect of self-efficacy was greatest when adolescents had stronger beliefs in the beneficial outcomes of adherence. These brief measures can be used to identify youths at risk of poor diabetes self-management. Interventions targeting self-efficacy may lead to improved diabetes self-management.

Gamma interferon paradoxically inhibits the development of diabetes in the NOD mouse.

Gamma interferon (IFN-gamma) has been thought to play an important role in the pathogenesis of diabetes. This report determines if rIFN-gamma administration to NOD mice paradoxically inhibits the development of diabetes. Injections of recombinant rIFN-gamma of 5 x 10(3), 20 x 10(3), and 100 x 10(3) units, dose dependently inhibited the development of diabetes. The maximal rIFN-gamma dose decreased the incidence of diabetes from 74% in control animals to 42%. 100x10(3) unit rIFN-gamma dose significantly decreased insulitis score, and increased islet number. The development of diabetes in irradiated NOD mice was slower in animals injected with spleen cells from rIFN-gamma treated than from saline treated NOD mice suggesting that rIFN-gamma decreases anti-islet effector cell activity. The susceptibility to apoptosis was increased in splenic cells of rIFN-gamma treated mice. The expressions of the co-stimulatory molecules B7-2 and ICAM-1 were significantly increased in spleen cells of rIFN-gamma treated mice while the expression of MHC class I was decreased. In vitro studies demonstrated that NOD mouse mononuclear spleen cells preincubated with rIFN-gamma and subsequently cocultured with responder cells, potently inhibited responder T-cell proliferative responses. rIFN-gamma administration decreased IL-12 and IL-2 mRNA expression in spleen cells while increasing IL-1 expression. In conclusion, rIFN-gamma inhibits the diabetic process in NOD mice by decreasing anti-islet effector activity and in turn decreasing insulitis and islet destruction. The suppression of Th1 cell related cytokines and/or augmentation of the macrophage cytokine IL-1 may play a role in the diabetes sparing effect of rIFN-gamma.