Cell adhesion plays a critical role in many cellular functions, such as the hemostatic/thrombotic process, inflammatory reactions, and adaptive immune response. Many cell adhesion processes involve crosstalk between multiple ligand-receptor systems through intracellular signaling. To elucidate such crosstalk requires analysis of the synergistic or antagonistic effects of binding and signalling of multi-receptor species. Current techniques for these analyses, e.g., atomic force microscopy (AFM) and biomembrane force probe (BFP) assays, are either labor-intensive, low-throughput, or limited in the types of ligands they can interrogate. Circumventing these limitations requires a technique for manipulating ligand interactions with and measuring the functional response of a population of cells. In this work, we have developed a microfluidic platform for studying the binding and signaling of multi-receptor species by separating their actions in space and time. The platform directs cells through a single channel and uses sequentially presented ligands for pre-processing and stimulating cells, followed by reporting of cell activation states and functional consequences. Our method precisely patterns multiple proteins in different spatial regions without gaps. We demonstrate the utility of our method by using this platform to analyze the crosstalk between platelet receptors, glycoprotein Ib and IIb-IIIa, in the context of platelet adhesion and signaling under flow. We show the clinical utility of this platform by applying it to analyze whole blood samples and to assess differences in the activation of platelets between healthy and diabetic patients.

Ebolavirus (EBOV) infection in humans is a severe and often fatal disease, which demands effective interventional strategies for its prevention and treatment. The available vaccines, which are authorized under exceptional circumstances, use viral vector platforms and have serious disadvantages, such as difficulties in adapting to new virus variants, reliance on cold chain supply networks, and administration by hypodermic injection. Microneedle (MN) patches, which are made of an array of micron-scale, solid needles that painlessly penetrate into the upper layers of the skin and dissolve to deliver vaccines intradermally, simplify vaccination and can thereby increase vaccine access, especially in resource-constrained or emergency settings. The present study describes a novel MN technology, which combines EBOV glycoprotein (GP) antigen with a polyphosphazene-based immunoadjuvant and vaccine delivery system (poly[di(carboxylatophenoxy)phosphazene], PCPP). The protein-stabilizing effect of PCPP in the microfabrication process enabled preparation of a dissolvable EBOV GP MN patch vaccine with superior antigenicity compared to a non-polyphosphazene polymer-based analog. Intradermal immunization of mice with polyphosphazene-based MN patches induced strong, long-lasting antibody responses against EBOV GP, which was comparable to intramuscular injection. Moreover, mice vaccinated with the MN patches were completely protected against a lethal challenge using mouse-adapted EBOV and had no histologic lesions associated with ebolavirus disease.

Objective Many obese children with unprovoked diabetic ketoacidosis (DKA) display clinical features of type 2 diabetes during follow up. We describe the clinical presentation, autoimmune markers and the long-term course of obese and lean children with DKA. Research design and methods We reviewed the medical records on the initial acute hospitalization and outpatient follow-up care of 21 newly diagnosed obese and 20 lean children with unprovoked DKA at Emory University affiliated children’s hospitals between 1/2003 and 12/2006. Results Obese children with DKA were older and predominantly male, had acanthosis nigricans, and had lower prevalence of autoantibodies to islet cells and glutamic acid decarboxylase than lean children. Half of the obese, but none of the lean children with DKA achieve near-normoglycemia remission and discontinued insulin therapy during follow-up. Time to achieve remission was 2.2 ± 2.3 months. There were no differences on clinical presentation between obese children who achieved near-normoglycemia remission versus those who did not. The addition of metformin to insulin therapy shortly after resolution of DKA resulted in lower hemoglobin A1c (HbA1c) levels, higher rates of near-normoglycemia remission, and lower frequency of DKA recurrence. Near-normoglycemia remission, however, was of short duration and the majority of obese patients required reinstitution of insulin treatment within 15 months of follow-up. Conclusion In contrast to lean children with DKA, many obese children with unprovoked DKA display clinical and immunologic features of type 2 diabetes during follow-up. The addition of metformin to insulin therapy shortly after resolution of DKA improves glycemic control, facilitates achieving near-normoglycemia remission and prevents DKA recurrence in obese children with DKA.

Background Microneedles have previously been used to deliver insulin to animal models, but not in human subjects. This study tested the hypothesis that hollow microneedles can deliver insulin to modulate blood glucose levels in subjects with type 1 diabetes in a minimally invasive manner. Methods This study was carried out in two adults with type 1 diabetes and evaluated bolus delivery of lispro insulin using a hollow microneedle compared to a catheter infusion set (9 mm). The study first determined the minimum insulin delivery depth by administering insulin from microneedles inserted 1, 3.5, and 5 mm into the skin of fasting subjects and then assessed the efficacy of insulin delivery from microneedles inserted 1 mm into the skin to reduce postprandial glucose levels. Blood samples were periodically assayed for plasma free insulin and plasma glucose levels for up to 3.5 h. Results The first phase of the study indicated that microneedles inserted at the shallowest depth of 1 mm within the skin led to rapid insulin absorption and reduction in glucose levels. Bolus insulin delivery followed by consumption of a standardized meal in the second phase revealed that microneedles were effective in reducing postprandial glucose levels. Subjects reported no pain from microneedle treatments, and there were no adverse events. Conclusions This study provides the first proof of concept that hollow microneedles can effectively deliver bolus insulin to type 1 diabetes subjects in a minimally invasive manner.

Tissue interstitial fluid (ISF) surrounds cells and is an underutilized source of biomarkers that complements conventional sources such as blood and urine. However, ISF has received limited attention due largely to lack of simple collection methods. Here, we developed a minimally invasive, microneedle-based method to sample ISF from human skin that was well tolerated by participants. Using a microneedle patch to create an array of micropores in skin coupled with mild suction, we sampled ISF from 21 human participants and identified clinically relevant and sometimes distinct biomarkers in ISF when compared to companion plasma samples based on mass spectrometry analysis. Many biomarkers used in research and current clinical practice were common to ISF and plasma. Because ISF does not clot, these biomarkers could be continuously monitored in ISF similar to current continuous glucose monitors but without requiring an indwelling subcutaneous sensor. Biomarkers distinct to ISF included molecules associated with systemic and dermatological physiology, as well as exogenous compounds from environmental exposures. We also determined that pharmacokinetics of caffeine in healthy adults and pharmacodynamics of glucose in children and young adults with diabetes were similar in ISF and plasma. Overall, these studies provide a minimally invasive method to sample dermal ISF using microneedles and demonstrate human ISF as a source of biomarkers that may enable research and translation for future clinical applications.

Insulinomas are a rare cause of persistent hypoglycemia in a previously healthy child. In addition to symptoms of hypoglycemia, individuals with insulinomas usually present with a history of incessant caloric intake and weight gain due to a constant need to counter hypoglycemia. In addition to an extensive review of the literature, we report the first case oan insulinoma coexisting with reduced appetite secondary to anorexia nervosa in an adolescent female.

Abstract Background This study compared the pharmacokinetics, postprandial glycemic response, and pain associated with intradermal lispro insulin delivery using a microneedle with that of a conventional catheter. Subjects and Methods Five subjects with type 1 diabetes were administered a bolus infusion of lispro insulin using a 9-mm-long subcutaneous catheter (control treatment) and a 0.9-mm-long microneedle (study treatment), followed by consumption of a standardized meal. Blood samples were periodically assayed for plasma glucose and free insulin levels. Results Intradermal insulin infusion using microneedles reached peak insulin concentrations in approximately half the time and led to greater reduction in plasma glucose levels than subcutaneous catheters. Microneedles were also significantly less painful than the catheters. Conclusion The rapid pharmacokinetics and minimally invasive nature of intradermal insulin infusion using microneedles provide significant potential for improved diabetes management.

Diabetes is associated with an exaggerated platelet thrombotic response at sites of vascular injury. Biomechanical forces regulate platelet activation, although the impact of diabetes on this process remains ill-defined. Using a biomembrane force probe (BFP), we demonstrate that compressive force activates integrin α IIb β 3 on discoid diabetic platelets, increasing its association rate with immobilized fibrinogen. This compressive force-induced integrin activation is calcium and PI 3-kinase dependent, resulting in enhanced integrin affinity maturation and exaggerated shear-dependent platelet adhesion. Analysis of discoid platelet aggregation in the mesenteric circulation of mice confirmed that diabetes leads to a marked enhancement in the formation and stability of discoid platelet aggregates, via a mechanism that is not inhibited by therapeutic doses of aspirin and clopidogrel, but is eliminated by PI 3-kinase inhibition. These studies demonstrate the existence of a compression force sensing mechanism linked to α IIb β 3 adhesive function that leads to a distinct prothrombotic phenotype in diabetes.

BACKGROUND. Type 1 diabetes (T1D) results from destruction of pancreatic β cells by autoreactive effector T cells. We hypothesized that the immunomodulatory drug alefacept would result in targeted quantitative and qualitative changes in effector T cells and prolonged preservation of endogenous insulin secretion by the remaining β cells in patients with newly diagnosed T1D. METHODS. In a multicenter, randomized, double-blind, placebo-controlled trial, we compared alefacept (two 12-week courses of 15 mg/wk i.m., separated by a 12-week pause) with placebo in patients with recent onset of T1D. Endpoints were assessed at 24 months and included meal-stimulated C-peptide AUC, insulin use, hypoglycemic events, and immunologic responses. RESULTS. A total of 49 patients were enrolled. At 24 months, or 15 months after the last dose of alefacept, both the 4-hour and the 2-hour C-peptide AUCs were significantly greater in the treatment group than in the control group (P = 0.002 and 0.015, respectively). Exogenous insulin requirements were lower (P = 0.002) and rates of major hypoglycemic events were about 50% reduced (P < 0.001) in the alefacept group compared with placebo at 24 months. There was no apparent between-group difference in glycemic control or adverse events. Alefacept treatment depleted CD4+ and CD8+ central memory T cells (Tcm) and effector memory T cells (Tem) (P < 0.01), preserved Tregs, increased the ratios of Treg to Tem and Tcm (P < 0.01), and increased the percentage of PD-1+CD4+ Tem and Tcm (P < 0.01). CONCLUSIONS. In patients with newly diagnosed T1D, two 12-week courses of alefacept preserved C-peptide secretion, reduced insulin use and hypoglycemic events, and induced favorable immunologic profiles at 24 months, well over 1 year after cessation of therapy. TRIAL REGISTRATION.https://clinicaltrials.gov/ NCT00965458.