Nanotechnologies for Physiology-Informed Drug Delivery to the Lymphatic System.

Accompanying the increasing translational impact of immunotherapeutic strategies to treat and prevent disease has been a broadening interest across both bioscience and bioengineering in the lymphatic system. Herein, the lymphatic system physiology, ranging from its tissue structures to immune functions and effects, is described. Design principles and engineering approaches to analyze and manipulate this tissue system in nanoparticle-based drug delivery applications are also elaborated.

Combination bupropion SR and varenicline for smoking cessation: a systematic review.

BACKGROUND: Tobacco is the leading cause of preventable death in the world. Current cessation medications include nicotine replacement therapy (NRT), varenicline, and bupropion, while combination therapy primarily entails NRT with either varenicline or bupropion. However, recent studies have examined varenicline and bupropion in combination. OBJECTIVES: A systematic review assessing the efficacy and safety of combination varenicline and bupropion was conducted. METHODS: PubMed and Clinicaltrials.gov were searched using terms: "varenicline combination", "bupropion combination", "bupropion AND varenicline", and "bupropion AND varenicline combination smoking cessation", yielding four studies including 1193 total patients. RESULTS: Combination therapy yielded greater efficacy than varenicline monotherapy in two randomized controlled trials and one retrospective outcomes study. One single-arm Phase II trial provided additional efficacy and safety data. Of the prospective trials, one displayed a greater 4-week smoking abstinence for weeks 8-11 with combination (39.8%) versus monotherapy (25.9%) (OR = 1.89; 95% CI = 1.07-3.35). The other demonstrated greater prolonged abstinence (continuous abstinence from week 2) at 12 weeks (OR = 1.49; 95% CI = 1.05-2.12) and 26 weeks (OR = 1.52; 95% CI = 1.04-2.22), though results were not significant at 52 weeks in this study. The retrospective study displayed higher success rates (continuous abstinence rates at 52 weeks) with combination varenicline and bupropion (55.0%; compared to varenicline monotherapy (32.1%), p < 0.001). Subgroup analyses suggest that this combination may be more beneficial in males and patients with higher baseline nicotine dependence. CONCLUSION: To the authors' knowledge, this is the first review conducted to compile current literature on this novel pharmacotherapy combination for smoking cessation. Combination bupropion SR and varenicline displayed greater efficacy in smoking cessation than varenicline monotherapy, though further safety analysis is warranted to rule out additive psychiatric adverse effects.

Analyzing immune response to engineered hydrogels by hierarchical clustering of inflammatory cell subsets.

Understanding the immune response to hydrogel implantation is critical for the design of immunomodulatory biomaterials. To study the progression of inflammation around poly(ethylene glycol) hydrogels presenting Arg-Gly-Asp (RGD) peptides and vascular endothelial growth factor, we used temporal analysis of high-dimensional flow cytometry data paired with intravital imaging, immunohistochemistry, and multiplexed proteomic profiling. RGD-presenting hydrogels created a reparative microenvironment promoting CD206+ cellular infiltration and revascularization in wounded dorsal skin tissue. Unbiased clustering algorithms (SPADE) revealed significant phenotypic transition shifts as a function of the cell-adhesion hydrogel properties. SPADE identified an intermediate macrophage subset functionally regulating in vivo cytokine secretion that was preferentially recruited for RGD-presenting hydrogels, whereas dendritic cell subsets were preferentially recruited to RDG-presenting hydrogels. Last, RGD-presenting hydrogels controlled macrophage functional cytokine secretion to direct polarization and vascularization. Our studies show that unbiased clustering of single-cell data provides unbiased insights into the underlying immune response to engineered materials.

Dual delivery of IL-10 and AT-RvD1 from PEG hydrogels polarize immune cells towards pro-regenerative phenotypes.

Inflammation after traumatic injury or surgical intervention is both a protective tissue response leading to regeneration and a potential cause of wound complications. One potentially successful strategy to harness to pro-regenerative roles of host inflammation is the localized delivery of bioactive materials to induce immune suppressive cellular responses by cells responding to injury. In this study, we designed a fully synthetic poly (ethylene) glycol (PEG)-based hydrogel to release the specialized pro-resolving lipid mediator aspirin-triggered resolvin-D1 (AT-RvD1) and recombinant human interleukin 10 (IL-10). We utilized a unique side-by-side internally controlled implant design wherein bioactive hydrogels were implanted adjacent to control hydrogels devoid of immune modulatory factors in the dorsal skinfold window chamber. We also explored single-immune cell data with unsupervised approaches such as SPADE. First, we show that RGD-presenting hydrogel delivery results in enhanced immune cell recruitment to the site of injury. We then use intra-vital imaging to assess cellular recruitment and microvascular remodeling to show an increase in the caliber and density of local microvessels. Finally, we show that the recruitment and re-education of mononuclear phagocytes by combined delivery IL-10 and AT-RvD1 localizes immune suppressive subsets to the hydrogel, including CD206+ macrophages (M2a/c) and IL-10 expressing dendritic cells in the context of chronic inflammation following surgical tissue disruption. These data demonstrate the potential of combined delivery on the recruitment of regenerative cell subsets involved in wound healing complications.

Incorporation of a nucleoside analog maps genome repair sites in postmitotic human neurons.

Neurons are the longest-lived cells in our bodies and lack DNA replication, which makes them reliant on a limited repertoire of DNA repair mechanisms to maintain genome fidelity. These repair mechanisms decline with age, but we have limited knowledge of how genome instability emerges and what strategies neurons and other long-lived cells may have evolved to protect their genomes over the human life span. A targeted sequencing approach in human embryonic stem cell-induced neurons shows that, in neurons, DNA repair is enriched at well-defined hotspots that protect essential genes. These hotspots are enriched with histone H2A isoforms and RNA binding proteins and are associated with evolutionarily conserved elements of the human genome. These findings provide a basis for understanding genome integrity as it relates to aging and disease in the nervous system.

Immunotherapy via PD-L1-presenting biomaterials leads to long-term islet graft survival.

Antibody-mediated immune checkpoint blockade is a transformative immunotherapy for cancer. These same mechanisms can be repurposed for the control of destructive alloreactive immune responses in the transplantation setting. Here, we implement a synthetic biomaterial platform for the local delivery of a chimeric streptavidin/programmed cell death-1 (SA-PD-L1) protein to direct "reprogramming" of local immune responses to transplanted pancreatic islets. Controlled presentation of SA-PD-L1 on the surface of poly(ethylene glycol) microgels improves local retention of the immunomodulatory agent over 3 weeks in vivo. Furthermore, local induction of allograft acceptance is achieved in a murine model of diabetes only when receiving the SA-PD-L1-presenting biomaterial in combination with a brief rapamycin treatment. Immune characterization revealed an increase in T regulatory and anergic cells after SA-PD-L1-microgel delivery, which was distinct from naïve and biomaterial alone microenvironments. Engineering the local microenvironment via biomaterial delivery of checkpoint proteins has the potential to advance cell-based therapies, avoiding the need for systemic chronic immunosuppression.