Gluconeogenesis Flux in Metabolic Disease.

Gluconeogenesis is a critical biosynthetic process that helps maintain whole-body glucose homeostasis and becomes altered in certain medical diseases. We review gluconeogenic flux in various medical diseases, including common metabolic disorders, hormonal imbalances, specific inborn genetic errors, and cancer. We discuss how the altered gluconeogenic activity contributes to disease pathogenesis using data from experiments using isotopic tracer and spectroscopy methodologies. These in vitro, animal, and human studies provide insights into the changes in circulating levels of available gluconeogenesis substrates and the efficiency of converting those substrates to glucose by gluconeogenic organs. We highlight ongoing knowledge gaps, discuss emerging research areas, and suggest future investigations. A better understanding of altered gluconeogenesis flux may ultimately identify novel and targeted treatment strategies for such diseases.

Intermediate versus morning chronotype has lower vascular insulin sensitivity in adults with obesity.

AIM: Chronotype reflects a circadian rhythmicity that regulates endothelial function. While the morning chronotype (MORN) usually has low cardiovascular disease risk, no study has examined insulin action on endothelial function between chronotypes. We hypothesized intermediate chronotypes (INT) would have lower vascular insulin sensitivity than morning chronotype (MORN). MATERIALS AND METHODS: Adults with obesity were classified per Morningness-Eveningness Questionnaire (MEQ) as either MORN (n = 27, 22 female, MEQ = 63.7 ± 4.7, 53.8 ± 6.7 years, 35.3 ± 4.9 kg/m2) or INT (n = 29, 23 female, MEQ = 48.8 ± 6.7, 56.6 ± 9.0 years, 35.7 ± 6.1 kg/m2). A 120 min euglycaemic-hyperinsulinaemic clamp (40 mU/m2/min, 90 mg/dl) was conducted to assess macrovascular insulin sensitivity via brachial artery flow-mediated dilation (%FMD; conduit artery), post-ischaemic flow velocity (resistance arteriole), as well as microvascular insulin sensitivity via contrast-enhanced ultrasound [e.g. microvascular blood volume (perfusion)]. Fasting plasma arginine and citrulline, as well as fasting and clamp-derived plasma endothelin-1 and nitrate/nitrite, were assessed as surrogates of vasoconstriction and nitric oxide-mediated vasodilation. Aerobic fitness (VO2max) and body composition (dual-energy X-ray absorptiometry) were also collected. RESULTS: MORN had a higher VO2max compared with INT (p < .01), although there was no difference in fat mass. While fasting FMD was similar between groups, insulin lowered FMD corrected to shear stress and microvascular blood volume in INT compared with MORN after co-varying for VO2max (both p ≤ .02). INT also had a lower fasting nitrate (p = .03) and arginine (p = .07). Higher MEQ correlated with elevated FMD (r = 0.33, p = .03) and lower post-ischaemic flow velocity (r = -0.33, p = .03) as well as shear rate (r = -0.36, p = .02) at 120 min. CONCLUSION: When measured during the morning, INT had a lower vascular insulin sensitivity than MORN. Additional work is needed to understand endothelial function differences among chronotypes to optimize cardiovascular disease risk reduction.

Lymph node metrics following neoadjuvant therapy to refine patient selection for adjuvant chemotherapy in resected pancreatic cancer: A multi-institutional analysis.

BACKGROUND: In patients with localized pancreatic ductal adenocarcinoma (PDAC) undergoing neoadjuvant therapy (NAT) and resection, selection of adjuvant chemotherapy (AC) is typically guided by high-risk features on histopathologic examination. We evaluated the interaction between post-NAT lymph node metrics and AC receipt on survival. METHODS: Patients who received NAT followed by pancreatectomy (2010-2020) at seven centers were reviewed. Overall survival (OS) in patients receiving AC or not was stratified by lymph node positivity (LNP) or lymph node ratio (LNR) dichotomized at 0.1. Cox models evaluated the independent association between these nodal metrics, AC receipt, and OS. RESULTS: Of 464 patients undergoing NAT and resection, 264 (57%) received AC. Patients selected for AC were younger (median 63 vs. 67 years; p < 0.001), received shorter duration of NAT (2.8 vs. 3.2 months; p = 0.01), had fewer postoperative complications (Clavien-Dindo grade > 3: 1.2% vs. 11.7%; p < 0.001), and lower rates of pathologic complete response (4% vs. 11%; p = 0.01). The median number of nodes evaluated was similar between cohorts (n = 20 in both; p = 0.9). Post-NAT LNP rates were not different, and median LNR was 0.1, in AC and non-AC cohorts. Both LNP (hazard ratio [HR]: 2.1, p < 0.001) and LNR (0 < LNR ≤ 0.1: HR: 1.98, p = 0.002; LNR > 0.1: HR 2.46, p < 0.001) were independently associated with OS on Cox modeling, although receipt of AC was not associated with improved OS (median 30.6 vs. 29.4 months; p = 0.2). In patients with LNR > 0.1, receipt of AC was associated with significantly longer OS compared to non-AC (24 vs. 20 months, respectively; p = 0.04). CONCLUSIONS: LNR following NAT, not simply nodal positivity, may be useful to refine selection of AC in resected PDAC.

Anatomy and pathology of adductor canal (Hunter's canal).

Adductor canal (Hunter's canal) pathologies are often underdiagnosed, with the saphenous nerve being the most commonly affected. While uncommon, involvement of the femoral artery and vein can cause severe and irreversible complications if not detected early. Significant attention must be given to adductor canal pathologies because the musculoaponeurotic tunnel is predominantly fibrotic with minimal adipose tissue. As a result, any edema or space-occupying lesion can lead to early compression of the structures within the adductor canal. Incorporating adductor canal syndrome into the imaging differential diagnosis is essential. For diagnosing and sometimes managing these conditions. In this article, we describe the anatomy and spectrum of pathologies involving the Hunter's canal.

Glucagon changes substrate preference in gluconeogenesis.

Fasting hyperglycemia in diabetes mellitus is caused by unregulated glucagon secretion that activates gluconeogenesis (GNG) and increases the use of pyruvate, lactate, amino acids, and glycerol. Studies of GNG in hepatocytes, however, tend to test a limited number of substrates at nonphysiologic concentrations. Therefore, we treated cultured primary hepatocytes with three identical substrate mixtures of pyruvate/lactate, glutamine, and glycerol at serum fasting concentrations, where a different U-13C- or 2-13C-labeled substrate was substituted in each mix. In the absence of glucagon stimulation, 80% of the glucose produced in primary hepatocytes incorporated either one or two 13C-labeled glycerol molecules in a 1:1 ratio, reflecting the high overall activity of this pathway. In contrast, glucose produced from 13C-labeled pyruvate/lactate or glutamine rarely incorporated two labeled molecules. While glucagon increased the glycerol and pyruvate/lactate contributions to glucose carbon by 1.6- and 1.8-fold, respectively, the glutamine contribution to glucose carbon was increased 6.4-fold in primary hepatocytes. To account for substrate 13C carbon loss during metabolism, we also performed a metabolic flux analysis, which confirmed that the majority of glucose carbon produced by primary hepatocytes was from glycerol. In vivo studies using a PKA-activation mouse model that represents elevated glucagon activity confirmed that most circulating lactate carbons originated from glycerol, but very little glycerol was derived from lactate carbons, reflecting glycerol's importance as a carbon donor to GNG. Given the diverse entry points for GNG substrates, hepatic glucagon action is unlikely to be due to a single mechanism.

Exercise blood pressure and heart rate responses to graded exercise testing in intermediate versus morning chronotypes with obesity.

Exaggerated exercise blood pressure (BP) is linked to cardiovascular disease (CVD). Although evening chronotypes have greater CVD risk than morning (Morn) types, it is unknown if exercise BP differs in intermediate (Int) types. Adults with obesity were classified as either Morn [n = 23 (18 females), Morning-Eveningness Questionnaire (MEQ) = 63.96 ± 1.0, 54.74 ± 1.4 yr, 33.7 ± 0.6 kg/m2] or Int [n = 23 (19 females), MEQ = 51.36 ± 1.1, 55.96 ± 1.8 yr, 37.2 ± 1.2 kg/m2] chronotype per MEQ. A graded, incremental treadmill test to maximal aerobic capacity (V̇o2max) was conducted. Systolic (SBP) and diastolic (DBP) blood pressure and mean arterial pressure (MAP), rate pressure product (RPP), heart rate (HR), and rate of perceived intensity (RPE) were determined at baseline, 4 min, 6 min, and maximal stages. HR recovery (HRR; maximum postexercise) was determined at 1 and 2 min postexercise. Preexercise fasted aortic waveforms (applanation tonometry), plasma leptin, nitrate/nitrite (nitric oxide bioavailability), and body composition (dual X-ray, DXA) were also collected. Int had lower V̇o2max and plasma nitrate (both P ≤ 0.02) than Morn. No difference in preexercise BP, aortic waveforms, or body composition were noted between groups, although higher plasma leptin was seen in Int compared with Morn (P = 0.04). Although Int had higher brachial DBP and MAP across exercise stages (both P ≤ 0.05) and higher HR, RPE, and RPP at 6 min of exercise (all P ≤ 0.05), covarying for V̇o2max nullified the BP, but not HR or RPE, difference. HRR was greater in Morn independent of V̇o2max (P = 0.046). Fasted leptin correlated with HR at exercise stage 4 (r = 0.421, P = 0.041) and 6 min (r = 0.593, P = 0.002). This observational study suggests that Int has exaggerated BP and HR responses to exercise compared with Morn, although fitness abolished BP differences.NEW & NOTEWORTHY This study compares blood pressure and heart rate responses with graded, incremental exercise between morning and intermediate chronotype adults with obesity. Herein, blood pressure responses to exercise were elevated in intermediate compared with morning chronotype, although V̇o2max abolished this observation. However, heart rate responses to exercise were higher in intermediate vs. morning chronotypes independent of fitness. Collectively, this exercise hemodynamic response among intermediate chronotype may be related to reduced aerobic fitness, altered nitric oxide metabolism, and/or elevated aortic waveforms.

Complex spinal dysraphism: myelomenigocele associated with dorsal bony spur, split cord malformation type I, syringomyelia, lipoma and tethered cord.

Variations in split cord malformation (SCM) are known. However, association of SCM type I with myelomeningocele along with same level dorsal bony spur has not been described previously. We report a 1-year old male child who presented with these findings with associated syringomyelia, lipoma and tethered cord.

Pilot Study Evaluating Cross-Disciplinary Educational Material to Improve Patients' Knowledge of Palliative Radiation Therapy.

Palliative radiation therapy (PRT) is underutilized, partially due to misconceptions about its risks, benefits, and indications. The objective of this pilot study was to determine if patients with metastatic cancer would gain knowledge from educational material describing PRT and perceive it as useful in their care. A one-page handout conveying information about the purpose, logistics, benefits, risks, and common indications for PRT was offered to patients undergoing treatment for incurable, metastatic solid tumors in one palliative care clinic and four medical oncology clinics. Participants read the handout, then completed a questionnaire assessing its perceived value. Seventy patients participated between June and December 2021. Sixty-five patients (93%) felt they learned from the handout (40% learned "lots"), and 69 (99%) felt the information was useful (53% "very useful"). Twenty-one patients (30%) were previously unaware that PRT can relieve symptoms, 55 (79%) were unaware that PRT can be delivered in five treatments or less, and 43 (61%) were unaware that PRT usually has few side effects. Sixteen patients (23%) felt they currently had symptoms not being treated well enough, and 34 (49%) felt they had symptoms that radiation might help with. Afterwards, most patients felt more comfortable bringing symptoms to a medical oncologist's (n = 57, 78%) or radiation oncologist's (n = 51, 70%) attention. Patient-directed educational material about PRT, provided outside of a radiation oncology department, was perceived by patients as improving their knowledge and adding value in their care, independent of prior exposure to a radiation oncologist.

Glucagon-like peptide-1 effect on ß-cell function varies according to diabetes remission status after Roux-en-Y gastric bypass.

AIMS: The contribution of endogenous glucagon-like peptide (GLP)-1 to ß-cell function after Roux-en-Y gastric bypass surgery (RYGB) is well established in normoglycaemic individuals, but not in those with postoperative hyperglycaemia. We, therefore, studied the effect of GLP-1 on ß-cell function in individuals with varying degrees of type 2 diabetes mellitus (T2D) control after RYGB. MATERIALS AND METHODS: Glucose, insulin secretion rates, ß-cell glucose sensitivity and glucagon were measured during an oral glucose tolerance test before (saline only) and at 3, 12 and 24 months after RYGB with and without infusion of the GLP-1 receptor blocker exendin9-39 (EX9). The cohort was retrospectively classified based on T2D remission (REM) status at the latest study time point: REM (n = 5), persistent T2D (n = 8), or impaired glucose tolerance (n = 16). RESULTS: EX9 blunted the increase in ß-cell glucose sensitivity at 3 months (-44.1%, p < .001) and 12 months (-43.3%, p < .001), but not at 24 months (-12.4%, p = .243). EX9 enhanced postprandial glucagon concentrations by 62.0% at 3 months (p = .008), 46.5% at 12 months (p = .055), and 30.4% at 24 months (p = .017). EX9 counterintuitively decreased glucose concentrations at 3 months in the entire cohort (p < .001) but had no effect on glycaemia at 12 and 24 months in persistent T2D and impaired glucose tolerance; it minimally worsened glycaemia in REM at 12 months. CONCLUSIONS: GLP-1 blockade reversed the improvement in ß-cell function observed after RYGB, but this effect varied temporally and by REM status. GLP-1 blockade transiently and minimally worsened glycaemia only in REM, and lowered postprandial glucose values at 3 months, regardless of REM status.

Updated Blood Pressure Guidelines: Implications for Athletes.

PURPOSE OF REVIEW: To review the prevalence, short- and long-term impact of exercise on blood pressure, and the evaluation and treatment of hypertension in competitive athletes. RECENT FINDINGS: Due, in part, to inconsistencies in measurement and the definitions used, the true prevalence of hypertension is unknown as reports range from 0 to 83%. With recent changes in the blood pressure guidelines, the proportion of athletes that meet criteria for elevated blood pressure or stage 1 hypertension has increased dramatically with over one-third of collegiate and professional athletes meeting criteria for hypertension. Data consistently show that American-style football players, particularly linemen, display the highest rates of hypertension. These athletes typically have a larger body mass index, higher body fat percentage, and weight gain in serial follow-up. Many athletes with hypertension have traditional risk factors, and, to date, there is no evidence of a causal relationship between long-term sport participation and increased risk of developing hypertension. Many more athletes now meet criteria for hypertension, given the updated blood pressure guidelines. This should be taken as an opportunity for early intervention, as athletes are not immune to the development of cardiovascular risk factors and disease.

Tracking the carbons supplying gluconeogenesis.

As the burden of type 2 diabetes mellitus (T2DM) grows in the 21st century, the need to understand glucose metabolism heightens. Increased gluconeogenesis is a major contributor to the hyperglycemia seen in T2DM. Isotope tracer experiments in humans and animals over several decades have offered insights into gluconeogenesis under euglycemic and diabetic conditions. This review focuses on the current understanding of carbon flux in gluconeogenesis, including substrate contribution of various gluconeogenic precursors to glucose production. Alterations of gluconeogenic metabolites and fluxes in T2DM are discussed. We also highlight ongoing knowledge gaps in the literature that require further investigation. A comprehensive analysis of gluconeogenesis may enable a better understanding of T2DM pathophysiology and identification of novel targets for treating hyperglycemia.

Surgical oncology operative experience at a high-volume safety-net hospital during the COVID-19 pandemic.

BACKGROUND: The coronavirus (COVID-19) pandemic led to disruptions in operative and hospital capabilities as the country triaged resources and canceled elective procedures. This study details the operative experience of a safety-net hospital for cancer-related operations during a 3-month period at the height of the pandemic. METHODS: Patients operated on for or diagnosed with malignancies of the abdomen, breast, skin, or soft-tissue (September 3, 2020-September 6, 2020) were identified from operative/clinic schedules. Sociodemographics, tumor and treatment characteristics, and COVID-19 information was identified through retrospective chart review of a prospectively maintained database. Descriptive statistics were calculated. RESULTS: Fifty patients evaluated within this window underwent oncologic surgery. Median age was 61 (interquartile range: 53-68), 56% were female, 86% were White, and 66% were Hispanic. The majority (28%) were for colon cancer. Only two patients tested positive for COVID-19 preoperatively or within 30 days of their operation. There were no mortalities during the 1-year study period. CONCLUSION: During the COVID-19 pandemic, many hospitals and operative centers limited interventions to preserve resources, but oncologic procedures continued at many large-volume academic cancer centers. This study underscores the importance of continuing to offer surgery during the pandemic for surgical oncology cases at safety-net hospitals to minimize delays in time-sensitive oncologic treatment.

Alternatives to Opioid Education and a Prescription Drug Monitoring Program Cumulatively Decreased Outpatient Opioid Prescriptions.

INTRODUCTION: Deaths have increased, and prescription medications are involved in a significant percentage of deaths. Emergency department (ED) changes to managing acute pain and prescription drug monitoring programs (PDMPs) can impact the potential for abuse. METHODS: We analyzed the impact of a series of quality improvement initiatives on the opioid prescribing habits of emergency department physicians and advanced practice providers. We compared historical prescribing patterns with those after three interventions: 1) the implementation of a PDMP, 2) clinician education on alternatives to opioids (ALTOs), and 3) electronic health record (EHR) process changes. RESULTS: There was a 61.8% decrease in the percentage of opioid-eligible ED discharges that received a prescription for an opioid from 19.4% during the baseline period to 7.4% during the final intervention period. Among these discharges, the cumulative effect of the interventions resulted in a 17.3% decrease in the amount of morphine milligram equivalents (MME) prescribed per discharge from a mean of 104.9 MME/discharge during the baseline period to 86.8 MME/discharge. In addition, the average amount of MME prescribed per discharge became aligned with recommended guidelines over the intervention periods. CONCLUSIONS: Initiating a PDMP and instituting an aggressive ALTO program along with EHR-modified process flows have cumulative benefits in decreasing MME prescribed in an acute ED setting.

Catecholamine response to exercise in patients with non-obstructive hypertrophic cardiomyopathy.

KEY POINTS: Intense physical activity, a potent stimulus for sympathetic nervous system activation, is thought to increase the risk of malignant ventricular arrhythmias among patients with hypertrophic cardiomyopathy (HCM). As a result, the majority of patients with HCM deliberately reduce their habitual physical activity after diagnosis and this lifestyle change puts them at risk for sequelae of a sedentary lifestyle: weight gain, hypertension, hyperlipidaemia, insulin resistance, coronary artery disease, and increased morbidity and mortality. We show that plasma catecholamine levels remain stably low at exercise intensities below the ventilatory threshold, a parameter that can be defined during cardiopulmonary exercise testing, but rise rapidly at higher intensities of exercise. These findings suggest that cardiopulmonary exercise testing may be a useful tool to provide an individualized moderate-intensity exercise prescription for patients with HCM. ABSTRACT: Intense physical activity, a potent stimulus for sympathetic nervous system activation, is thought to increase the risk of malignant ventricular arrhythmias among patients with hypertrophic cardiomyopathy (HCM). However, the impact of exercise intensity on plasma catecholamine levels among HCM patients has not been rigorously defined. We conducted a prospective observational case-control study of men with non-obstructive HCM and age-matched controls. Laboratory-based cardiopulmonary exercise testing coupled with serial phlebotomy was used to define the relationship between exercise intensity and plasma catecholamine levels. Compared to controls (C, n = 5), HCM participants (H, n = 9) demonstrated higher left ventricular mass index (115 ± 20 vs. 90 ± 16 g/m2 , P = 0.03) and maximal left ventricular wall thickness (16 ± 1 vs. 8 ± 1 mm, P < 0.001) but similar body mass index, resting heart rate, peak oxygen consumption (H = 40 ± 13 vs. C = 42 ± 7 ml/kg/min, P = 0.81) and heart rate at the ventilatory threshold (H = 78 ± 6 vs. C = 78 ± 4% peak heart rate, P = 0.92). During incremental effort exercise in both groups, concentrations of adrenaline and noradrenaline were unchanged through low- and moderate-exercise intensity until reaching a catecholamine threshold (H = 82 ± 4 vs. C = 85 ± 3% peak heart rate, P = 0.86) after which levels of both molecules rose rapidly. In patients with mild non-obstructive HCM, plasma catecholamine levels remain stably low at exercise intensities below the ventilatory threshold but rise rapidly at higher intensities of exercise. Routine cardiopulmonary exercise testing may be a useful tool to provide an individualized moderate-intensity exercise prescription for patients with HCM.

Nanoparticle physicochemical properties determine the activation of intracellular complement.

The complement system plays an essential role in both innate and adaptive immunity. The traditional understanding of this system comes from studies investigating complement proteins produced by the liver and present in plasma to "complement" the immune cell-mediated response to invading pathogens. Recently, it has been reported that immune cells including, but not limited to, T-cells and monocytes, express complement proteins. This complement is referred to as intracellular (IC) and implicated in the regulation of T-cell activation. The mechanisms and the structure-activity relationship between nanomaterials and IC, however, are currently unknown. Herein, we describe a structure-activity relationship study demonstrating that under in vitro conditions, only polymeric materials with cationic surfaces activate IC in T-cells. The effect also depends on particle size and occurs through a mechanism involving membrane damage, thereby IC on the cell surface serves as a self-opsonization marker in response to the nanoparticle-triggered danger affecting the cell integrity.

Structure and Composition Define Immunorecognition of Nucleic Acid Nanoparticles.

Nucleic acid nanoparticles (NANPs) have evolved as a new class of therapeutics with the potential to detect and treat diseases. Despite tremendous advancements in NANP development, their immunotoxicity, one of the major impediments in clinical translation of traditional therapeutic nucleic acids (TNAs), has never been fully characterized. Here, we describe the first systematically studied immunological recognition of 25 representative RNA and DNA NANPs selected to have different design principles and physicochemical properties. We discover that, unlike traditional TNAs, NANPs used without a delivery carrier are immunoquiescent. We show that interferons (IFNs) are the key cytokines triggered by NANPs after their internalization by phagocytic cells, which agrees with predictions based on the experiences with TNAs. However, in addition to type I IFNs, type III IFNs also serve as reliable biomarkers of NANPs, which is usually not characteristic of TNAs. We show that overall immunostimulation relies on NANP shapes, connectivities, and compositions. We demonstrate that, like with traditional TNAs, plasmacytoid dendritic cells serve as the primary interferon producers among all peripheral blood mononuclear cells treated with NANPs, and scavenger receptor-mediated uptake and endosomal Toll-like receptor signaling are essential for NANP immunorecognition. The TLR involvement, however, is different from that expected for traditional TNA recognition. Based on these results, we suggest that NANP technology may serve as a prototype of auxiliary molecular language for communication with the immune system and the modulation of immune responses.

Toll-Like Receptor-Mediated Recognition of Nucleic Acid Nanoparticles (NANPs) in Human Primary Blood Cells.

Infusion reactions (IRs) create a translational hurdle for many novel therapeutics, including those utilizing nanotechnology. Nucleic acid nanoparticles (NANPs) are a novel class of therapeutics prepared by rational design of relatively short oligonucleotides to self-assemble into various programmable geometric shapes. While cytokine storm, a common type of IR, has halted clinical development of several therapeutic oligonucleotides, NANP technologies hold tremendous potential to bring these reactions under control by tuning the particle's physicochemical properties to the desired type and magnitude of the immune response. Recently, we reported the very first comprehensive study of the structure⁻activity relationship between NANPs' shape, size, composition, and their immunorecognition in human cells, and identified the phagolysosomal pathway as the major route for the NANPs' uptake and subsequent immunostimulation. Here, we explore the molecular mechanism of NANPs' recognition by primary immune cells, and particularly the contributing role of the Toll-like receptors. Our current study expands the understanding of the immune recognition of engineered nucleic acid-based therapeutics and contributes to the improvement of the nanomedicine safety profile.

Erratum: Hong, E., et al. Toll-Like Receptor-Mediated Recognition of Nucleic Acid Nanoparticles (NANPs) in Human Primary Blood Cells. Molecules 2019, 24, 1094.

The Molecules Editorial Office wishes to make the following erratum to this paper [...].

RNA Fibers as Optimized Nanoscaffolds for siRNA Coordination and Reduced Immunological Recognition.

RNA is a versatile biomaterial that can be used to engineer nanoassemblies for personalized treatment of various diseases. Despite promising advancements, the design of RNA nanoassemblies with minimal recognition by the immune system remains a major challenge. Here, an approach is reported to engineer RNA fibrous structures to operate as a customizable platform for efficient coordination of siRNAs and for maintaining low immunostimulation. Functional RNA fibers are studied in silico and their formation is confirmed by various experimental techniques and visualized by atomic force microscopy (AFM). It is demonstrated that the RNA fibers offer multiple advantages among which are: i) programmability and modular design that allow for simultaneous controlled delivery of multiple siRNAs and fluorophores, ii) reduced immunostimulation when compared to other programmable RNA nanoassemblies, and iii) simple production protocol for endotoxin-free fibers with the option of their cotranscriptional assembly. Furthermore, it is shown that functional RNA fibers can be efficiently delivered with various organic and inorganic carriers while retaining their structural integrity in cells. Specific gene silencing triggered by RNA fibers is assessed in human breast cancer and melanoma cell lines, with the confirmed ability of functional fibers to selectively target single nucleotide mutations.

Feraheme® suppresses immune function of human T lymphocytes through mitochondrial damage and mitoROS production.

Despite attractive properties for both therapeutic and diagnostic applications, the clinical use of iron oxide nanoparticles (IONPs) is limited to iron replacement in severely anemic patient populations. While several studies have reported about the immunotoxicity of IONPs, the mechanisms of this toxicity are mostly unknown. We conducted a mechanistic investigation using an injectable form of IONP, Feraheme®. In the cultures of primary human T cells, Feraheme induced miotochondrial oxidative stress and resulted in changes in mitochondrial dynamics, architecture, and membrane potential. These molecular events were responsible for the decrease in cytokine production and proliferation of mitogen-activated T cells. The induction of mitoROS by T cells in response to Feraheme was insufficient to induce total redox imbalance at the cellular level. Consequently, we resolved this toxicity by the addition of the mitochondria-specific antioxidant MitoTEMPO. We further used these findings to develop an experimental framework consisting of critical assays that can be used to estimate IONP immunotoxicity. We explored this framework using several immortalized T-cell lines and found that none of them recapitulate the toxicity observed in the primary cells. Next, we compared the immunotoxicity of Feraheme to that of other FDA-approved iron-containing complex drug formulations and found that the mitochondrial damage and the resulting suppression of T-cell function are specific to Feraheme. The framework, therefore, can be used for comparing the immunotoxicity of Feraheme with that of its generic versions, while other iron-based complex drugs require case-specific mechanistic investigation.