In recent years, various nanotechnology platforms in the area of medical biology, including both diagnostics and therapy, have gained remarkable attention. Moreover, research and development of engineered multifunctional nanoparticles as pharmaceutical drug carriers have spurred exponential growth in applications to medicine in the last decade. Design principles of these nanoparticles, including nano-emulsions, dendrimers, nano-gold, liposomes, drug-carrier conjugates, antibody-drug complexes, and magnetic nanoparticles, are primarily based on unique assemblies of synthetic, natural, or biological components, including but not limited to synthetic polymers, metal ions, oils, and lipids as their building blocks. However, the potential success of these particles in the clinic relies on consideration of important parameters such as nanoparticle fabrication strategies, their physical properties, drug loading efficiencies, drug release potential, and, most importantly, minimum toxicity of the carrier itself. Among these, lipid-based nanoparticles bear the advantage of being the least toxic for in vivo applications, and significant progress has been made in the area of DNA/RNA and drug delivery using lipid-based nanoassemblies. In this review, we will primarily focus on the recent advances and updates on lipid-based nanoparticles for their projected applications in drug delivery. We begin with a review of current activities in the field of liposomes (the so-called honorary nanoparticles), and challenging issues of targeting and triggering will be discussed in detail. We will further describe nanoparticles derived from a novel class of amphipathic lipids called bolaamphiphiles with unique lipid assembly features that have been recently examined as drug/DNA delivery vehicles. Finally, an overview of an emerging novel class of particles (based on lipid components other than phospholipids), solid lipid nanoparticles and nanostructured lipid carriers will be presented. We conclude with a few examples of clinically successful formulations of currently available lipid-based nanoparticles.

Radiation-based therapies aided by nanoparticles have been developed since decades, and can be primarily categorized into two main platforms. First, delivery of payload of photo-reactive drugs (photosensitizers) using the conventional nanoparticles, and second, design and development of photo-triggerable nanoparticles (primarily liposomes) to attain light-assisted on-demand drug delivery. The main focus of this review is to provide an update of the history, current status and future applications of photo-triggerable lipid-based nanoparticles (light-sensitive liposomes). We will begin with a brief overview on the applications of liposomes for delivery of photosensitizers, including the choice of photosensitizers for photodynamic therapy, as well as the currently available light sources (lasers) used for these applications. The main segment of this review will encompass the details on the strategies to develop photo-triggerable designer liposomes for their drug delivery function. The principles underlying the assembly of photoreactive lipids into nanoparticles (liposomes) and photo-triggering mechanisms will be presented. We will also discuss factors that limit the applications of these liposomes for in vivo triggered drug delivery and emerging concepts that may lead to the biologically viable photo-activation strategies. We will conclude with our view point on the future perspectives of light-sensitive liposomes in the clinic.

We previously reported the formulation and physical properties of HER2 (Human Epidermal Growth Factor Receptor 2)-specific Affibody (ZHER2:342-Cys) conjugated thermosensitive liposomes (HER2+ Affisomes). Here we examined localized delivery potential of these Affisomes by monitoring cellular interactions, intracellular uptake, and hyperthermia-induced effects on drug delivery. We modified ZHER2:342-Cys by introducing a glycine-serine spacer before the C-terminus cysteine (called ZHER2-GS-Cys) to achieve accessibility to cell-surface expressed HER2. This modification did not affect HER2-specific binding and ZHER2-GS-Cys retained its ability to conjugate to the liposomes containing dipalmitoyl phosphatidyl choline: DSPE-PEG2000-Malemide, 96:04 mole ratios (HER2+ Affisomes). HER2+ Affisomes were either (i) fluorescently labeled with rhodamine-PE and calcein or (ii) loaded with an anticancer drug Doxorubicin (DOX). Fluorescently labeled HER2+ Affisomes showed at least 10 fold increase in binding to HER2+ cells (SK-BR-3) when compared to HER2− cells (MDA-MB-468) at 37°C. A competition experiment using free ZHER2-GS-Cys blocked HER2+ Affisomes-SK-BR-3 cell associations. Imaging with confocal microscopy showed that HER2+ Affisomes accumulated in the cytosol of SK-BR-3 cells at 37°C. Hyperthermia-induced intracellular release experiments showed that the treatment of HER2+ Affisome/SK-BR-3 cell complexes with a 45°C (±1°C) pre-equilibrated buffer resulted in cytosolic delivery of calcein. Substantial calcein release was observed within 20 minutes at 45°C, with no effect on cell viability under these conditions. Similarly, DOX-loaded HER2+ Affisomes showed at least 2–3 fold higher accumulation of DOX in SK-BR-3 cells as compared to control liposomes. DOX-mediated cytotoxicity was more pronounced in SK-BR-3 cells especially at lower doses of HER2+ Affisomes. Brief exposure of liposome-cell complexes at 45°C prior to the onset of incubations for cell killing assays resulted in enhanced cytotoxicity for Affisomes and control liposomes. However, Doxil (a commercially available liposome formulation) showed significantly lower toxicity under identical conditions. Therefore, our data demonstrate that HER2+ Affisomes encompass both targeting and triggering potential and hence may prove to be viable nano drug delivery carriers for breast cancer treatment.

The CD22 antigen is a viable target for therapeutic intervention for B-cell lymphomas. Several therapeutic anti-CD22 antibodies as well as an anti-CD22-based immunotoxin (HA22) are currently under investigation in clinical settings. Coupling of anti-CD22 reagents with a nano-drug delivery vehicle is projected to significantly improve treatment efficacies. Therefore, we generated a mutant of the targeting segment of HA22 (a CD22 scFv) to increase its soluble expression (mut-HA22), and conjugated it to the surface of sonicated liposomes to generate immunoliposomes (mut-HA22-liposomes). We examined liposome binding and uptake by CD22 + B-lymphocytes (BJAB) by using calcein and/or rhodamine PE-labeled liposomes. We also tested the effect of targeting on cellular toxicity with doxorubicin-loaded liposomes. We report that: (i) Binding of mut-HA22-liposomes to BJAB cells was significantly greater than liposomes not conjugated with mut-HA22 (control liposomes), and mut-HA22-liposomes bind to and are taken in by BJAB cells in a dose and temperature-dependent manner, respectively; (ii) This binding occurred via the interaction with the cellular CD22 as pre-incubation of the cells with mut-HA22 blocked subsequent liposome binding; (iii) Intracellular localization of mut-HA22-liposomes at 37°C but not at 4°C indicated that our targeted liposomes were taken up through an energy dependent process via receptor-mediated endocytosis; and (iv) Mut-HA22-liposomes loaded with doxorubicin exhibited at least 2-3 fold more accumulation of doxorubicin in BJAB cells as compared to control liposomes. Moreover, these liposomes showed at least a 2-4 fold enhanced killing of BJAB or Raji cells (CD22 + ), but not SUP-T1 cells (CD22 -). Taken together these data suggest that these 2 nd -generation liposomes may serve as promising carriers for targeted drug delivery to treat patients suffering from B-cell lymphoma.

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Despite numerous first-line treatment interventions, adequately managing a patient’s postamputation pain can be difficult. Peripheral nerve stimulation has emerged as a safe neuromodulatory intervention that can be used for many etiologies of chronic pain. We performed a systemic review to appraise the evidence of peripheral nerve stimulation use for improvement in postamputation pain. This was performed in Ovid, Cochrane databases, OVID, Scopus, Web of Science Core Collection, and PubMed. The primary outcome was improvement in postamputation pain after use of peripheral nerve stimulation. Secondary outcomes included improvements in functional status, opioid usage, and mood. Data extraction and risk of bias assessments were performed independently in a blinded manner. Of the 989 studies identified, 13 studies were included consisting of three randomized control trials, seven observational studies, and three case series. While large heterogeneity limited definitive conclusions, the included studies generally demonstrated favorable outcomes regarding pain reduction. Each included study that used an objective pain scale demonstrated clinically significant pain improvements. Per the Grading of Recommendations, Assessment, Development, and Evaluations criteria, there is very low-quality Grading of Recommendations, Assessment, Development, and Evaluations evidence supporting that peripheral nerve stimulation is associated with improvements in pain intensity for postamputation pain. Future prospective, comparative, and well-powered studies assessing the use of peripheral nerve stimulation for postamputation pain are warranted.

BackgroundAppropriate empiric antibiotic therapy is associated with decreased mortality and recurrence in patients with Enterobacteriaceae bacteremia (EB). Increasing bacterial resistance adds an additional layer to this complex clinical scenario. Swift utilization of appropriate antibiotics is crucial for improved patient outcomes. However, prolonged and excessively broad antibiotic coverage is not without its own complications. Our study aimed to review the appropriateness of empiric antibiotics for EB.MethodsA retrospective chart review of all patients >18 years of age who were admitted to a single academic community hospital during 2018 EB anytime throughout their hospitalization. The primary endpoint was the appropriateness of empiric antibiotic therapy, defined as receiving active therapy prior to the return of antimicrobial sensitivities that were susceptible to the empiric agents used. Appropriateness was further adjusted for standard of care (SOC) practices. Specifically, despite in vitro susceptibility of piperacillin/tazobactam and cefepime, carbapenem therapy is preferred for ESBL infections.ResultsOur study identified 178 patients with EB. Most common organisms included E.coli (64.6%), K. pneumoniae (11.8%) and P. mirabilis (7.3%). Resistance patterns included 1 CRE (0.57%) and 17 ESBL (9.7%) isolates. Most common sources of infection included urinary (63.5%) and intraabdominal (13.5%). Based on the sensitivity reports of tested isolates, 83.7% of patients received appropriate empiric antibiotics. After adjustment for SOC, 11.8% of ESBL patients (2/17) and 0% of CRE (0/1) patients received appropriate therapy. Comparatively 89.0% of patients without ESBL or CRE (137/154) received appropriate care (P < 0.0001).ConclusionThe results of this study demonstrate that across our patient population, over 80% of patients received appropriate empiric antibiotics for EB; however, this percentage was dramatically lower for patients with ESBL or CRE infections. This highlights room for improved rapid diagnosis and identification of risk factors predisposing to resistant organisms thereby decreasing the time to appropriate antibiotic therapy. Disclosures All authors: No reported disclosures.