Artificial MicroRNAs as siRNA Shuttles: Improved Safety as Compared to shRNAs In vitro and In vivo

RNA interference (RNAi) provides a promising therapeutic approach to human diseases. However, data from recent reports demonstrate that short-hairpin RNAs (shRNAs) may cause cellular toxicity, and this warrants further investigation of the safety of using RNAi vectors. Earlier, in comparing hairpin-based RNAi vectors, we noted that shRNAs are highly expressed and yield an abundance of unprocessed precursors, whereas artificial microRNAs (miRNAs) are expressed at lower levels and are processed efficiently. We hypothesized that unprocessed shRNAs arise from the saturation of endogenous RNAi machinery, which poses likely a burden to cells. In this study, we tested that hypothesis by assessing the relative effects of shRNAs and artificial miRNAs on the processing and function of miRNAs. In competition assays, shRNAs disrupted miRNA biogenesis and function, whereas artificial miRNAs avoided this interference even when dosed to silence as effectively as shRNAs. We next compared the safety of these vectors in mouse cerebella, and found that shRNAs cause Purkinje cell neurotoxicity. By contrast, artificial miRNA expression was well tolerated, resulting in effective target gene silencing in Purkinje cells. These findings, together with data from earlier work in mouse striata, suggest that miRNA-based platforms are better suited for therapeutic silencing in the mammalian brain.     

SGLT2 inhibitors in patients with type 2 diabetes and renal disease: overview of current evidence

Chronic kidney disease (CKD) is a frequent complication of type 2 diabetes mellitus (T2DM) and is associated with poor clinical outcomes, including an increased risk of all-cause and cardiovascular mortality, as well as adverse economic and social effects. Slowing the development and progression of CKD remains an unmet clinical need in patients with T2DM. Sodium-glucose co-transporter 2 (SGLT2) inhibitors are widely used for the management of T2DM and have effects beyond glucose lowering that include cardiovascular benefits and potential renoprotective effects. Although the glucose-lowering efficacy of these agents is dependent on renal function, the cardiovascular and renal benefits of SGLT2 inhibition appear to be maintained to estimated glomerular filtration levels as low as 30 mL/min/1.73 m². Clinical evidence has indicated that these agents can reduce the risk of development or worsening of albuminuria, a marker of renal damage, through a range of mechanisms. These include blood pressure lowering, reduction of intraglomerular pressure and hyperfiltration, modification of inflammatory processes, reduction of ischemia-related renal injury, and increases in glucagon levels. The blood pressure-lowering effect of SGLT2 inhibitors is maintained in people with CKD and could further contribute to reduced renal burden, as well as potentially offering synergistic effects with antihypertensive therapies in these patients. Several cardiovascular outcomes trials (CVOTs) have included renal endpoints, adding to the growing evidence of the potential renoprotective effects of these agents in patients with T2DM. Several ongoing dedicated renal outcomes trials will provide further guidance on the potential clinical role of SGLT2 inhibitors in slowing the development and progression of renal impairment in individuals with T2DM.     

Clinical nursing and midwifery education in the pandemic age

The COVID-19 pandemic has disrupted clinical nursing and midwifery education. This disruption has long-term implications for the nursing and midwifery workforce and for future healthcare responses to pandemics. Solutions may include enhanced partnerships between schools of nursing and midwifery and health service providers and including schools of nursing and midwifery in preparedness planning. These suggestions notwithstanding, we call upon national and international nursing and midwifery bodies to study how to further the clinical education of nurses and midwives during pandemics and other times of crisis.     

Dressler's syndrome following pulmonary vein isolation for atrial fibrillation

Dressler's syndrome, characterized by features of fever, pericarditis and pericardial effusion typically occurs in the weeks to months following a myocardial infarction. The syndrome has also been described following several other myocardial and pericardial pathologies, including two reports of Dressler's syndrome following radio-frequency ablation. We describe a case of Dressler's syndrome following a pulmonary vein isolation procedure, which is being performed with increasing frequency as a treatment strategy for atrial fibrillation.     

A catalytic di-heme bis-Fe(IV) intermediate, alternative to an Fe(IV)=O porphyrin radical

High-valent iron species are powerful oxidizing agents in chemical and biological catalysis. The best characterized form of an Fe(V) equivalent described in biological systems is the combination of a b-type heme with Fe(IV)=O and a porphyrin or amino acid cation radical (termed Compound I). This work describes an alternative natural mechanism to store two oxidizing equivalents above the ferric state for biological oxidation reactions. MauG is an enzyme that utilizes two covalently bound c-type hemes to catalyze the biosynthesis of the protein-derived cofactor tryptophan tryptophylquinone. Its natural substrate is a monohydroxylated tryptophan residue present in a 119-kDa precursor protein. An EPR-silent di-heme reaction intermediate of MauG was trapped. Mössbauer spectroscopy revealed the presence of two distinct Fe(IV) species. One is consistent with an Fe(IV)=O (ferryl) species (δ = 0.06 mm/s, ΔE_Q = 1.70 mm/s). The other is assigned to an Fe(IV) heme species with two axial ligands from protein (δ = 0.17 mm/s, ΔE_Q = 2.54 mm/s), which has never before been described in nature. This bis-Fe(IV) intermediate is remarkably stable but readily reacts with its native substrate. These findings broaden our views of how proteins can stabilize a highly reactive oxidizing species and the scope of enzyme-catalyzed posttranslational modifications.     

Connective tissue growth factor/CCN2 overexpression in mouse synovial lining results in transient fibrosis and cartilage damage

OBJECTIVE: Characteristics of osteoarthritis (OA) include cartilage damage, fibrosis, and osteophyte formation. Connective tissue growth factor (CTGF; also known as CCN2), is found in high levels in OA chondrocytes and is frequently involved in fibrosis, bone formation, and cartilage repair. The present study was therefore undertaken to investigate the potential role of CTGF in OA pathophysiology. METHODS: We transfected the synovial lining of mouse knee joints with a recombinant adenovirus expressing human CTGF and measured synovial fibrosis and proteoglycan content in cartilage on days 1, 3, 7, 14, and 28. Messenger RNA (mRNA) expression in synovium and cartilage was measured on days 3, 7, and 21. RESULTS: CTGF induced synovial fibrosis, as indicated by accumulation of extracellular matrix and an increase in procollagen type I-positive cells. The fibrosis reached a maximum on day 7 and had reversed by day 28. Levels of mRNA for matrix metalloproteinase 3 (MMP-3), MMP-13, ADAMTS-4, ADAMTS-5, tissue inhibitor of metalloproteinases 1 (TIMP-1), and transforming growth factor beta were elevated in the fibrotic tissue. TIMP-1 expression was elevated on day 3, while expression of other genes did not increase until day 7 or later. CTGF induced proteoglycan depletion in cartilage as early as day 1. Maximal depletion was observed on days 3-7. Cartilage damage was reduced by day 28. A high level of MMP-3 mRNA expression was found in cartilage. CTGF overexpression did not induce osteophyte formation. CONCLUSION: CTGF induces transient fibrosis that is reversible within 28 days. Overexpression of CTGF in knee joints results in reversible cartilage damage, induced either by the high CTGF levels or via factors produced by the CTGF-induced fibrotic tissue.     

Effects of colesevelam hydrochloride on low-density lipoprotein cholesterol and high-sensitivity C-reactive protein when added to statins in patients with hypercholesterolemia

Elevated high-sensitivity C-reactive protein (hs-CRP) levels are associated with an increased risk of atherosclerotic coronary heart disease (CHD). The addition of the bile acid sequestrants, such as colesevelam hydrochloride (HCl), to statins further reduces low-density lipoprotein (LDL) cholesterol levels. However, the effects of approved cholesterol-lowering bile acid sequestrants on hs-CRP have not previously been reported. Three randomized, double-blind, placebo-controlled, parallel, 6-week clinical trials of similar design investigated the efficacy of adding colesevelam HCl to stable simvastatin, atorvastatin, or pravastatin treatment in 204 patients with primary hypercholesterolemia. The primary end point was the mean percent change in the LDL cholesterol levels. Secondary end points included the effects on other lipid parameters and hs-CRP levels. A pooled analysis showed that adding colesevelam HCl to statin therapy significantly lowered LDL cholesterol levels (21 mg/dl or 16% mean reduction from baseline, p = 0.0013, and 11 mg/dl or 9% mean reduction compared with placebo, p = 0.0003). Four times as many patients receiving colesevelam HCl plus a statin achieved a LDL cholesterol target of <100 mg/dl compared with patients receiving a statin plus placebo (39% vs 10%, respectively, p <0.0001). The incidence of mild gastrointestinal adverse effects was slightly higher in the colesevelam HCl plus statin group than in the placebo plus statin group. Finally, the differences in the change in hs-CRP levels with colesevelam HCl plus statin therapy were significant compared with the changes with placebo plus statin (median change -23%, p = 0.0069). In conclusion, this is the first report suggesting that an approved cholesterol-lowering bile acid sequestrant, specifically colesevelam HCl, decreases hs-CRP levels when added to statin therapy.     

Improving hyperglycemia management in the intensive care unit: preliminary report of a nurse-driven quality improvement project using a redesigned insulin infusion algorithm

PURPOSE: The purpose of this study was to assess the feasibility of a nurse-driven effort to improve hyperglycemia management in the intensive care unit (ICU) setting. METHODS: The setting was the ICU of a large urban hospital. The program was composed of 3 components: nurses as leaders, a clinical pathway to identify patients in need of hyperglycemia therapy, and implementation of a redesigned insulin infusion algorithm (the Columnar Insulin Dosing Chart). Time to reach a target glucose range of 80 to 110 mg/dL (4.4-6.1 mmol/L) was evaluated. RESULTS: One hundred sixteen ICU nurses were trained in the project. The Columnar Insulin Dosing Chart was applied to 20 patients. The average time required to reach the target blood glucose range was 12.8 hours. Below-target blood glucose levels were 6.9% of all blood glucose levels recorded, but only 0.9% were below 60 mg/dL (3.3 mmol/L). There was no sustained hypoglycemia, and no persistent clinical findings attributable to hypoglycemia were noted. Barriers to implementing the project included an increased nursing workload, the need for more finger-stick blood glucose monitors, and the need to acquire new finger-lancing devices that allowed for shallower skin puncture and increased patient comfort. CONCLUSIONS: Tighter glycemic control goals can be attained in a busy ICU by a nurse-led team using a pathway for identifying and treating hyperglycemia, clear decision support tools, and adequate nurse education. The novel chart-based insulin infusion algorithm chosen as the standard for this pilot was an effective tool for reducing the blood glucose to target range with no clinically significant hypoglycemia.     

Efficacy and safety of torcetrapib, a novel cholesteryl ester transfer protein inhibitor, in individuals with below-average high-density lipoprotein cholesterol levels on a background of atorvastatin.

OBJECTIVES: This study sought to evaluate the efficacy and safety of torcetrapib in patients with low high-density lipoprotein cholesterol (HDL-C) levels receiving background atorvastatin. BACKGROUND: Elevating HDL-C levels may reduce the residual cardiovascular risk that is observed in patients treated with statin therapy. Torcetrapib (a cholesteryl ester transfer protein inhibitor) increases HDL-C and decreases low-density lipoprotein cholesterol (LDL-C). METHODS: This was a multicenter, double-blind, randomized trial. Patients with below-average HDL-C (men <44 mg/dl; women <54 mg/dl) who were eligible for statin therapy according to National Cholesterol Education Program Adult Treatment Panel III guidelines or who had LDL-C >130 mg/dl at screening entered an 8-week run-in period with atorvastatin 20 mg/day before randomization (n = 174) to torcetrapib 10, 30, 60, or 90 mg/day or placebo for 8 weeks. Atorvastatin was continued during treatment with torcetrapib. RESULTS: After 8 weeks, the percent change from baseline with torcetrapib (least-squares mean difference from placebo) ranged from 8.3% to 40.2% for HDL-C (p < or = 0.0001 for 30-mg and higher doses) and from 0.6% to -18.9% for LDL-C (p < 0.01 for 60-mg and 90-mg doses). Particle size for both HDL and LDL increased with torcetrapib. The incidence of all-causality and treatment-related adverse events was similar across placebo and torcetrapib treatment groups with no evidence of a dose-related response. In some treatment groups, small increases in systolic and diastolic blood pressures were noted. CONCLUSIONS: In statin-eligible patients, torcetrapib plus background atorvastatin resulted in substantial, dose-dependent increases in HDL-C, accompanied by additional decreases in LDL-C beyond those seen with atorvastatin alone. Torcetrapib plus atorvastatin was generally well tolerated.     

Barriers to achieving optimal glycemic control in a multi-ethnic society: a US focus

The increasing prevalence of diabetes is particularly apparent in certain ethnic groups, such as African and Hispanic Americans. These groups generally also have poorer glycemic control and outcomes. To better understand the issues surrounding these problems and possible methods to overcome them we performed a literature review from the past 15 years on barriers to glycemic control with a focus on US data. The literature reveals that barriers may be inherent (eg, genetic, cultural, and language/communication) or acquired (eg, those associated with changes in lifestyle and socioeconomic factors). Healthcare interventions that take into consideration cultural and population-specific characteristics can reduce the prevalence and severity of diabetes and its resulting complications. Implementing such strategies will require suitable education for patients and providers, the availability of culturally-sensitive, patient-centered healthcare teams, the creation of collaborative relationships between providers and patients, better use of community resources, and assistance for patients to make informed decisions about available treatment options. There is also evidence suggesting that at the same level of glucose control Hispanics and African Americans have the same degree of complications as whites; therefore, good control is essential for the future well-being of all patients. Addressing these issues may help to decrease the ethnic disparities that currently exist in diabetes care.