Recent advances in lipid nanoparticles for delivery of nucleic acid,mRNA, and gene editing-based therapeutics

Lipid nanoparticles (LNPs) are becoming popular as a means of delivering therapeutics, including those based on nucleic acids and mRNA. The mRNA-based coronavirus disease 2019 vaccines are perfect examples to highlight the role played by drug delivery systems in advancing human health. The fundamentals of LNPs for the delivery of nucleic acid- and mRNA-based therapeutics, are well established. Thus, future research on LNPs will focus on addressing the following: expanding the scope of drug delivery to different constituents of the human body, expanding the number of diseases that can be targeted, and studying the change in the pharmacokinetics of LNPs under physiological and pathological conditions. This review article provides an overview of recent advances aimed at expanding the application of LNPs, focusing on the pharmacokinetics and advantages of LNPs. In addition, analytical techniques, library construction and screening, rational design, active targeting, and applicability to gene editing therapy have also been discussed.     

A Proposal for an Alternative Approach to Particle Size Method Development During Early-Stage Small Molecule Pharmaceutical Development

Particle size analysis in the pharmaceutical industry has long been a source of debate regarding how best to define measurement accuracy; the degree to which the result of a measurement or calculation conforms to the true value. Defining a “true” value for the size of a particle can be challenging as the output of its measurement will differ because of variations in measurement approaches, instrumental differences and calculation methods. Consequently, for “real” particles, a universal “true” value does not exist and accuracy is therefore not a definable characteristic. Accordingly, precision is then a measure of the ability to reproducibly achieve a measurement of unknown relevance.This article proposes, in place of accuracy, a means to define the “appropriateness” of a measurement in line with the critical quality attributes (CQA) of the material being characterized. The decision as to whether the measurement is correct should involve a link to the CQA; that is, correlation should be demonstrated, without which the measured particle size cannot be defined as a critical material attribute.Correspondingly, methods should also be able to provide sufficient precision to demonstrate discrimination relating to variation in the CQA. The benefits and challenges of this approach are discussed.     

AuNP flares-capped mesoporous silica nanoplatform for MTH1 detection and inhibition

The human mutT homologue MTH1, a nucleotide pool sanitizing enzyme, represents a vulnerability factor and an attractive target for anticancer therapy. However, there is currently a lack of selective and effective platforms for the detection and inhibition of MTH1 in cells. Here, we demonstrate for the first time a gold nanoparticle (AuNP) flares-capped mesoporous silica nanoparticle (MSN) nanoplatform that is capable of detecting MTH1 mRNA and simultaneously suppressing MTH1 activity. The AuNP flares are made from AuNPs that are functionalized with a dense shell of MTH1 recognition sequences hybridized to short cyanine (Cy5)-labeled reporter sequences and employed to seal the pores of MSN to prevent the premature MTH1 inhibitors (S-crizotinib) release. Just like the pyrotechnic flares that produce brilliant light when activated, the resulting AuNP flares@MSN (S-crizotinib) undergo a significant burst of red fluorescence enhancement upon MTH1 mRNA binding. This hybridization event subsequently induces the opening of the pores and the release of S-crizotinib in an mRNA-dependent manner, leading to significant cytotoxicity in cancer cells and improved therapeutic response in mouse xenograft models. We anticipate that this nanoplatform may be an important step toward the development of MTH1-targeting theranostics and also be a useful tool for cancer phenotypic lethal anticancer therapy.     

In vivo epigenetic effects induced by engineered nanomaterials: A case study of copper oxide and laser printer-emitted engineered nanoparticles

Evidence continues to grow on potential environmental health hazards associated with engineered nanomaterials (ENMs). While the geno- and cytotoxic effects of ENMs have been investigated, their potential to target the epigenome remains largely unknown. The aim of this study is two-fold: 1) determining whether or not industry relevant ENMs can affect the epigenome in vivo and 2) validating a recently developed in vitro epigenetic screening platform for inhaled ENMs. Laser printer-emitted engineered nanoparticles (PEPs) released from nano-enabled toners during consumer use and copper oxide (CuO) were chosen since these particles induced significant epigenetic changes in a recent in vitro companion study. In this study, the epigenetic alterations in lung tissue, alveolar macrophages and peripheral blood from intratracheally instilled mice were evaluated. The methylation of global DNA and transposable elements (TEs), the expression of the DNA methylation machinery and TEs, in addition to general toxicological effects in the lung were assessed. CuO exhibited higher cell-damaging potential to the lung, while PEPs showed a greater ability to target the epigenome. Alterations in the methylation status of global DNA and TEs, and expression of TEs and DNA machinery in mouse lung were observed after exposure to CuO and PEPs. Additionally, epigenetic changes were detected in the peripheral blood after PEPs exposure. Altogether, CuO and PEPs can induce epigenetic alterations in a mouse experimental model, which in turn confirms that the recently developed in vitro epigenetic platform using macrophage and epithelial cell lines can be successfully utilized in the epigenetic screening of ENMs.     

A modality-specific somatosensory evoked potential test protocol for clinical evaluation: A feasibility study

ObjectiveWe aimed to establish an objective neurophysiological test protocol that can be used to assess the somatosensory nervous system.MethodsIn order to assess most fiber subtypes of the somatosensory nervous system, repetitive stimuli of seven different modalities (touch, vibration, pinprick, cold, contact heat, laser, and warmth) were synchronized with the electroencephalogram (EEG) and applied on the cheek and dorsum of the hand and dorsum of the foot in 21 healthy subjects and three polyneuropathy (PNP) patients. Latencies and amplitudes of the modalities were assessed and compared. Patients received quantitative sensory testing (QST) as reference.ResultsWe found reproducible evoked potentials recordings for touch, vibration, pinprick, contact-heat, and laser stimuli. The recording of warm-evoked potentials was challenging in young healthy subjects and not applicable in patients. Latencies were shortest within Aβ-fiber-mediated signals and longest within C-fibers. The test protocol detected function loss within the Aβ-fiber and Aδ-fiber-range in PNP patients. This function loss corresponded with QST findings.ConclusionIn this pilot study, we developed a neurophysiological test protocol that can specifically assess most of the somatosensory modalities. Despite technical challenges, initial patient data appear promising regarding a possible future clinical application.SignificanceEstablished and custom-made stimulators were combined to assess different fiber subtypes of the somatosensory nervous system using modality-specific evoked potentials.     

Melatonin reduces oxidative stress and improves vascular function in pulmonary hypertensive newborn sheep

Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN.     

Sentinel lymph node localization and staging with a low-dose of superparamagnetic iron oxide (SPIO) enhanced MRI and magnetometer in patients with cutaneous melanoma of the extremity - The MAGMEN feasibility study

BackgroundIn patients with melanoma, sentinel lymph node (SLN) status is pivotal for treatment decisions. Current routine for SLN detection combines Technetium^99m (Tc⁹⁹) lymphoscintigraphy and blue dye (BD). The primary aim of this study was to examine the feasibility of using a low dose of superparamagnetic iron oxide (SPIO) injected intracutaneously to detect and identify the SLN, and the secondary aim was to investigate if a low dose of SPIO would enable a preoperative MRI-evaluation of SLN status.MethodsPatients with melanoma of the extremities were eligible. Before surgery, a baseline MRI of the nodal basin was followed by an injection of a low dose (0.02–0.5 mL) of SPIO and then a second MRI (SPIO-MRI). Tc⁹⁹ and BD was used in parallel and all nodes with a superparamagnetic and/or radioactive signal were harvested and analyzed.ResultsFifteen patients were included and the SLNB procedure was successful in all patients (27 SLNs removed). All superparamagnetic SLNs were visualized by MRI corresponding to the same nodes on scintigraphy. Micrometastatic deposits were identified in four SLNs taken from three patients, and SPIO-MRI correctly predicted two of the metastases. There was an association between MRI artefacts in the lymph node and the dose SPIO given.DiscussionIt is feasible to detect SLN in patients with melanoma using a low dose of SPIO injected intracutaneously compared with the standard dual technique. A low dose of SPIO reduces the lymph node MRI artefacts, opening up for a non-invasive assessment of SLN status in patients with cancer.