Humanized C3 Mouse: A Novel Accelerated Model of C3 Glomerulopathy

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Cardiac Strain in a Swine Model of Regional Hibernating Myocardium: Effects of CoQ10 on Contractile Reserve Following Bypass Surgery

There is conflicting clinical evidence whether administration of coenzyme Q10 (CoQ10) improves function following coronary artery bypass graft surgery (CABG). Using a swine model of hibernating myocardium, we tested whether daily CoQ10 would improve contractile function by MRI at 4-week post-CABG. Twelve pigs underwent a thoracotomy and had a constrictor placed on the left anterior descending (LAD). At 12 weeks, they underwent off-pump bypass and received daily dietary supplements of either CoQ10 (10 mg/kg/day) or placebo. At 4-week post-CABG, circumferential strain measurements in the hibernating LAD region from placebo and CoQ10 groups were not different and increased to a similar extent with dobutamine (?14.7?±?0.6 versus ?14.8?±?0.1, respectively (NS)). Post-sacrifice, oxidant stress markers were obtained in the mitochondrial isolates and protein carbonyl in the placebo, and CoQ10 groups were 6.14?±?0.36 and 5.05?±?0.32 nmol/mg, respectively (NS). In summary, CoQ10 did not improve contractile reserve or reduce oxidant stress at 4-week post-CABG.     

Migration of titanium dioxide microparticles and nanoparticles through the body and deposition in the gingiva: an experimental study in rats

The aim of this experimental work was to evaluate deposition of titanium dioxide (TiO₂) microparticles and nanoparticles, which could originate from titanium bioimplants, in the gingiva. Wistar rats were injected intraperitoneally (i.p.) with a suspension of TiO₂ particles of different sizes (150, 10, or 5 nm). The rats were killed 12 months post‐injection, and the buccal and lingual gingivae were resected and evaluated using light and scanning electron microscopy. Energy‐dispersive X‐ray spectroscopy (EDS) was used to confirm the presence of titanium in deposits of microparticles and nanoparticles, and the concentration of titanium in tissues was measured using inductively coupled plasma–mass spectrometry (ICP‐MS). Histological examination showed that all experimental groups exhibited agglomerates, in the gingiva, of titanium particles of micrometer size range, with no associated inflammatory response. Higher concentrations of titanium traces were shown, by ICP‐MS, in both buccal and lingual tissues of all experimental groups compared with their matched controls. Titanium concentrations were significantly higher in the buccal gingiva than in the lingual gingiva, and after injection with 5‐nm particles than with 10‐nm particles in both localizations. Titanium microparticles and nanoparticles deposit in the gingiva, and mostly on the buccal side. Gingival deposition of titanium could be considered a tissue indicator of tribocorrosion processes of titanium bioimplants.     

Identification of a novel selective serotonin reuptake inhibitor by coupling monoamine transporter-based virtual screening and rational molecular hybridization

Ligand virtual screening (VS) using the vestibular binding pocket of a 3-D monoamine transporter (MAT) computational model followed by in vitro pharmacology led to the identification of a human serotonin transporter (hSERT) inhibitor with modest affinity (hSERT K(i) = 284 nM). Structural comparison of this VS-elucidated compound, denoted MI-17, to known SERT ligands led to the rational design and synthesis of DJLDU-3-79, a molecular hybrid of MI-17 and dual SERT/5-HT(1A) receptor antagonist SSA-426. Relative to MI-17, DJLDU-3-79 displayed 7-fold improvement in hSERT binding affinity and a 3-fold increase in [(3)H]-serotonin uptake inhibition potency at hSERT/HEK cells. This hybrid compound displayed a hSERT:hDAT selectivity ratio of 50:1, and a hSERT:hNET (human norepinephrine transporter) ratio of >200:1. In mice, DJLDU-3-79 decreased immobility in the tail suspension test comparable to the SSRI fluvoxamine, suggesting that DJLDU-3-79 may possess antidepressant properties. This proof of concept study highlights MAT virtual screening as a powerful tool for identifying novel inhibitor chemotypes and chemical fragments for rational inhibitor design.     

An Update on the Clinical Development of Proprotein Convertase Subtilisin Kexin 9 Inhibitors,Novel Therapeutic Agents for Lowering Low‐Density Lipoprotein Cholesterol

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays an essential role in the degradation of low‐density lipoprotein C (LDL‐C) receptors, and PCSK9 inhibitors have recently emerged as a potential treatment option to reduce LDL‐C. Our paper reviewed the current available Phase II clinical trials of PCSK9 inhibitors for the treatment of dyslipidemia. A second objective of this review was to evaluate the potential clinical role of PCSK9 inhibitors in the management of dyslipidemia. Studies evaluating the efficacy and safety of any PCSK9 inhibitors in patients with dyslipidemia were included. The monoclonal antibodies REGN727/SAR236553 and AMG145 have the most published clinical data. Seven phase II trials were retrieved that evaluated the efficacy and safety of REGN727/SAR236553 or AMG145 in patients with either hypercholesterolemia or heterozygous familial hypercholesterolemia (HeFH). These two agents significantly decreased LDL‐C levels either as monotherapy or in combination with other lipid‐lowering agents. REGN727/SAR236553 and AMG145 have been well tolerated. The ongoing phase III trials of these two agents are summarized. REGN727/SAR236553 and AMG145 have demonstrated the potential to further decrease LDL‐C levels when added to conventional lipid‐lowering therapy. Morbidity and mortality data are required to define their roles in clinical practice.     

Orexin A decreases lipid peroxidation and apoptosis in a novel hypothalamic cell model

Current data support the idea that hypothalamic neuropeptide orexin A (OxA; hypocretin 1) mediates resistance to high fat diet-induced obesity. We previously demonstrated that OxA elevates spontaneous physical activity (SPA), that rodents with high SPA have higher endogenous orexin sensitivity, and that OxA-induced SPA contributes to obesity resistance in rodents. Recent reports show that OxA can confer neuroprotection against ischemic damage, and may decrease lipid peroxidation. This is noteworthy as independent lines of evidence indicate that diets high in saturated fats can decrease SPA, increase hypothalamic apoptosis, and lead to obesity. Together data suggest OxA may protect against obesity both by inducing SPA and by modulation of anti-apoptotic mechanisms. While OxA effects on SPA are well characterized, little is known about the short- and long-term effects of hypothalamic OxA signaling on intracellular neuronal metabolic status, or the physiological relevance of such signaling to SPA. To address this issue, we evaluated the neuroprotective effects of OxA in a novel immortalized primary embryonic rat hypothalamic cell line. We demonstrate for the first time that OxA increases cell viability during hydrogen peroxide challenge, decreases hydrogen peroxide-induced lipid peroxidative stress, and decreases caspase 3/7 induced apoptosis in an in vitro hypothalamic model. Our data support the hypothesis that OxA may promote obesity resistance both by increasing SPA, and by influencing survival of OxA-responsive hypothalamic neurons. Further identification of the individual mediators of the anti-apoptotic and peroxidative effects of OxA on target neurons could lead to therapies designed to maintain elevated SPA and increase obesity resistance.     

Depressive symptoms and heart rate variability in postmenopausal women

BACKGROUND: Depressive symptoms have been associated with increased cardiac morbidity and mortality rates, but the pathophysiologic mechanism linking depressive symptoms to cardiovascular outcome has yet to be fully understood. Lower heart rate variability has also been associated with increased risk of cardiac events in healthy individuals and in patients with coronary artery disease. Findings regarding a relationship between depressive symptoms and heart rate variability that could explain increased cardiovascular risk have been inconsistent across studies. METHODS: As an ancillary study to the Women's Health Initiative Observational Study, 3372 postmenopausal women aged 50 to 83 years were enrolled for further evaluation using 24-hour ambulatory electrocardiographic monitoring. A shortened version of the Center for Epidemiological Studies Depression Scale and the Diagnostic Interview Schedule were administered. Women with adequate electrocardiographic data and depressive symptom information and without coronary artery disease were analyzed (n = 2627). RESULTS: Two hundred sixty-nine women (10.2%) had depressive symptoms as measured using the 2 instruments. Women with depressive symptoms had a higher mean +/- SD heart rate (77.4 +/- 9.6 vs 75.5 +/- 8.5 beats/min) and lower heart rate variability than women without depressive symptoms. All differences remained significant after adjusting for age (P<.01). CONCLUSIONS: Women with depressive symptoms had significant reductions in heart rate variability and higher heart rates, suggestive of increased sympathetic tone. These findings may contribute to the increased cardiac morbidity and mortality rates associated with depression in other studies.