Axon Myelination and Electrical Stimulation in a Microfluidic,Compartmentalized Cell Culture Platform

Axon demyelination contributes to the loss of sensory and motor function following injury or disease in the central nervous system. Numerous reports have demonstrated that myelination can be achieved in neuron/oligodendrocyte co-cultures. However, the ability to selectively treat neuron or oligodendrocyte (OL) cell bodies in co-cultures improves the value of these systems when designing mechanism-based therapeutics. We have developed a microfluidic-based compartmentalized culture system to achieve segregation of neuron and OL cell bodies while simultaneously allowing the formation of myelin sheaths. Our microfluidic platform allows for a high replicate number, minimal leakage, and high flexibility. Using a custom built lid, fit with platinum electrodes for electrical stimulation (10-Hz pulses at a constant 3 V with ~190 kΩ impedance), we employed the microfluidic platform to achieve activity-dependent myelin segment formation. Electrical stimulation of dorsal root ganglia resulted in a fivefold increase in the number of myelinated segments/mm² when compared to unstimulated controls (19.6 ± 3.0 vs. 3.6 ± 2.3 MBP⁺ segments/mm²). This work describes the modification of a microfluidic, multi-chamber system so that electrical stimulation can be used to achieve increased levels of myelination while maintaining control of the cell culture microenvironment.     

Green tea minimally affects biomarkers of inflammation in obese subjects with metabolic syndrome

Objective

Green tea (Camellia sinensis) has shown to exert cardioprotective benefits in observational studies. The objective of this clinical trial was to assess the effects of green tea on features of metabolic syndrome and inflammation in obese subjects.

Methods

We conducted a randomized controlled trial in obese subjects with metabolic syndrome. Thirty-five subjects [(mean ± SE) age 42.5 ± 1.7 y, body mass index 36.1 ± 1.3 kg/m²] completed the 8-wk study and were randomly assigned to receive green tea (4 cups/d), green tea extract (2 capsules and 4 cups water/d), or no treatment (4 cups water/d). Both the beverage and extract groups had similar dosing of epigallocatechin-3-gallate, the active green tea polyphenol. Fasting blood samples were collected at screening, 4 and 8 wk of the study.

Results

Green tea beverage or extract supplementation did not significantly alter features of metabolic syndrome or biomarkers of inflammation including adiponectin, C-reactive protein, interleukin-6, interleukin-1β, soluble vascular cell adhesion molecule-1, soluble intercellular adhesion molecule-1, leptin, or leptin:adiponectin ratio. However, both green tea beverage and extracts significantly reduced plasma serum amyloid alpha versus no treatment (P < 0.005).

Conclusion

This study suggests that the daily consumption of green tea beverage or extracts for 8 wk was well tolerated but did not affect the features of metabolic syndrome. However, green tea significantly reduced plasma serum amyloid alpha, an independent cardiovascular disease risk factor, in obese subjects with metabolic syndrome.     

MECP2 duplications in six patients with complex sex chromosome rearrangements

Duplications of the Xq28 chromosome region resulting in functional disomy are associated with a distinct clinical phenotype characterized by infantile hypotonia, severe developmental delay, progressive neurological impairment, absent speech, and proneness to infections. Increased expression of the dosage-sensitive MECP2 gene is considered responsible for the severe neurological impairments observed in affected individuals. Although cytogenetically visible duplications of Xq28 are well documented in the published literature, recent advances using array comparative genomic hybridization (CGH) led to the detection of an increasing number of microduplications spanning MECP2. In rare cases, duplication results from intrachromosomal rearrangement between the X and Y chromosomes. We report six cases with sex chromosome rearrangements involving duplication of MECP2. Cases 1-4 are unbalanced rearrangements between X and Y, resulting in MECP2 duplication. The additional Xq material was translocated to Yp in three cases (cases 1-3), and to the heterochromatic region of Yq12 in one case (case 4). Cases 5 and 6 were identified by array CGH to have a loss in copy number at Xp and a gain in copy number at Xq28 involving the MECP2 gene. In both cases, fluorescent in situ hybridization (FISH) analysis revealed a recombinant X chromosome containing the duplicated material from Xq28 on Xp, resulting from a maternal pericentric inversion. These cases add to a growing number of MECP2 duplications that have been detected by array CGH, while demonstrating the value of confirmatory chromosome and FISH studies for the localization of the duplicated material and the identification of complex rearrangements.     

Sleep Disturbances and Frailty Status in Older Community-Dwelling Men

OBJECTIVES: To test the hypothesis that sleep disturbances are independently associated with frailty status in older men. DESIGN: Cross‐sectional analysis of prospective cohort study. SETTING: Six U.S. centers. PARTICIPANTS: Three thousand one hundred thirty‐three men aged 67 and older. MEASUREMENTS: Self‐reported sleep parameters (questionnaire); objective parameters of sleep–wake patterns (actigraphy data collected for an average of 5.2 nights); and objective parameters of sleep‐disordered breathing, nocturnal hypoxemia, and periodic leg movements with arousals (PLMAs) (in‐home overnight polysomnography). Frailty status was classified as robust, intermediate stage, or frail using criteria similar to those used in the Cardiovascular Health Study frailty index. RESULTS: The prevalence of sleep disturbances, including poor sleep quality, excessive daytime sleepiness, short sleep duration, lower sleep efficiency, prolonged sleep latency, sleep fragmentation (greater nighttime wakefulness and frequent, long wake episodes), sleep‐disordered breathing, nocturnal hypoxemia, and frequent PLMAs, was lowest in robust men, intermediate in men in the intermediate‐stage group, and highest in frail men (P‐for‐trend ≤.002 for all sleep parameters). After adjusting for multiple potential confounders, self‐reported poor sleep quality (Pittsburgh Sleep Quality Index >5, multivariable odds ratio (MOR)=1.28, 95% confidence interval (CI)=1.09–1.50), sleep efficiency less than 70% (MOR=1.37, 95% CI=1.12–1.67), sleep latency of 60 minutes or longer (MOR=1.42, 95% CI=1.10–1.82), and sleep‐disordered breathing (respiratory disturbance index ≥15, MOR=1.38, 95% CI=1.15–1.65) were each independently associated with higher odds of greater frailty status. CONCLUSION: Sleep disturbances, including poor self‐reported sleep quality, lower sleep efficiency, prolonged sleep latency, and sleep‐disordered breathing, are independently associated with greater evidence of frailty.     

Identification of novel small molecule activators of nuclear factor-κB with neuroprotective action via high-throughput screening

Neuronal noncytokine-dependent p50/p65 nuclear factor-κB (the primary NF-κB complex in the brain) activation has been shown to exert neuroprotective actions. Thus neuronal activation of NF-κB could represent a viable neuroprotective target. We have developed a cell-based assay able to detect NF-κB expression enhancement, and through its use we have identified small molecules able to up-regulate NF-κB expression and hence trigger its activation in neurons. We have successfully screened approximately 300,000 compounds and identified 1,647 active compounds. Cluster analysis of the structures within the hit population yielded 14 enriched chemical scaffolds. One high-potency and chemically attractive representative of each of these 14 scaffolds and four singleton structures were selected for follow-up. The experiments described here highlighted that seven compounds caused noncanonical long-lasting NF-κB activation in primary astrocytes. Molecular NF-κB docking experiments indicate that compounds could be modulating NF-κB-induced NF-κB expression via enhancement of NF-κB binding to its own promoter. Prototype compounds increased p65 expression in neurons and caused its nuclear translocation without affecting the inhibitor of NF-κB (I-κB). One of the prototypical compounds caused a large reduction of glutamate-induced neuronal death. In conclusion, we have provided evidence that we can use small molecules to activate p65 NF-κB expression in neurons in a cytokine receptor-independent manner, which results in both long-lasting p65 NF-κB translocation/activation and decreased glutamate neurotoxicity.     

Daclatasvir/asunaprevir/beclabuvir fixed-dose combination in Japanese patients with HCV genotype 1 infection

Background

DCV-TRIO, a fixed-dose combination of daclatasvir (pangenotypic NS5A inhibitor), asunaprevir (NS3/4A protease inhibitor), and beclabuvir (non-nucleoside NS5B inhibitor), has achieved high rates of sustained virologic response at post-treatment Week 12 (SVR12) in phase 3 studies.

Methods

In this phase 3 study, DCV-TRIO for 12 weeks and daclatasvir plus asunaprevir (DUAL) for 24 weeks were studied in Japanese patients infected with HCV genotype 1 (99 % genotype 1b).

Results

SVR12 rates ≥95 % were achieved in both treatment-naive (N = 152) and interferon-experienced (N = 65) cohorts treated with DCV-TRIO for 12 weeks and were comparable across patient subgroups, including patients aged ≥65 years and those with cirrhosis. DUAL recipients (N = 75) had an SVR12 rate of 87 %. In the absence of baseline resistance-associated polymorphisms at positions NS5A-Y93H or -L31, SVR12 rates were 98 % with DCV-TRIO or DUAL. Among genotype 1b-infected patients with baseline Y93H or L31 polymorphisms, 35/38 (92 %) DCV-TRIO recipients, and 7/16 (44 %) DUAL recipients achieved SVR12. Adverse events, mostly liver related, led to treatment discontinuation in 10 % of DCV-TRIO recipients. In this group, SVR12 was achieved by 3/9 patients who discontinued before Week 4 and by 12/12 patients who completed ≥4 weeks of DCV-TRIO. Treatment-related serious adverse events occurred in 4 and 3 % of DCV-TRIO and DUAL recipients, respectively. Seven patients (9 %) discontinued DUAL due to adverse events. No deaths occurred.

Conclusion

SVR12 was achieved by 96 % of Japanese patients with HCV genotype 1 infection after 12 weeks of treatment with the DCV-TRIO regimen. DCV-TRIO and DUAL exhibited comparable safety profiles.

     

Increased renal angiotensin II AT1 receptor function in obese Zucker rat

Angiotensin II (Ang II) via the activation of AT1 receptors and subsequent stimulation of the tubular sodium transporters increases sodium and water reabsorption in the proximal tubule. An enhanced tubular action of Ang II is implicated in obesity related hypertension; however, the mechanism of such a phenomenon is unknown. Present study was designed to determine the AT1 receptor numbers and function in the proximal tubule of obese and lean Zucker rats. Obese Zucker rats were hypertensive and hyperinsulinemic. The plasma renin activity was similar in the lean and obese rats. Angiotensin II stimulated the Na,H-exchanger (NHE) activity in the proximal tubule, but the stimulatory response was markedly greater in obese than in lean rats. Similarly, Ang II caused greater inhibition in cAMP accumulation in the proximal tubule of obese compared to lean rats. The (125I]sar-Ang II binding revealed a 100% increase in the AT1 receptor number in the brush border membrane (BBM) of obese compared to lean rats. The Western blot analysis revealed a 36-51% increase in the Gi(alpha)1 and Gi(alpha)3 in the BBM of obese compared to lean rats. We conclude that increases in the AT1 receptor number and abundance of the Gi(alpha) on BBM may be responsible for the enhanced signaling and subsequent greater stimulation of NHE by Ang II in proximal tubules of obese rats. The greater stimulation of NHE by Ang II may contribute to the increased tubular sodium reabsorption and to the hypertension in obese Zucker rats.     

The role of dietary calcium in disease prevention

Of the leading causes of death among adults in developed nations (coronary heart disease, cancer and stroke) most are influenced by diet. Dietary intake is also associated with diseases causing significant morbidity, including hypertension, diabetes mellitus and osteoporosis. Although nutritional epidemiology is inexact as a science, certain reproducible studies have implicated links from nutrient availability in the body to chronic disease. Dietary calcium is one nutrient that has been the focus of multiple studies in an effort to discover its preventive effects. It has been implicated in the reduction of risk in osteoporosis, but kidney stone formation, obesity, hypertension and even cancer are lesser known areas in which increasing dietary calcium has yielded positive outcomes.     

Long‐term follow‐up of clinical trial patients treated for chronic HCV infection with daclatasvir‐based regimens

Background & Aims

Daclatasvir has achieved high sustained virologic response (SVR) rates in diverse hepatitis C virus (HCV) populations. This study evaluated the long‐term efficacy and safety of daclatasvir‐based regimens administered during clinical studies.

Methods

Patients enrolled within 6 months of parent study completion or protocol availability at the study sites. The primary objective was durability of SVR at follow‐up Week 12 (SVR12). Secondary objectives included analysing HCV sequences in non‐responders or responders who relapsed, and characterization of liver disease progression.

Results

Between 24 February 2012 and 17 July 2015, this study enrolled and began following 1503 recipients of daclatasvir‐based regimens (follow‐up cut‐off, 13 October 2015); 60% were male, 18% aged ≥65 years, 87% had genotype‐1a (42%) or ‐1b (45%) infection, and 18% had cirrhosis. Median follow‐up from parent study follow‐up Week 12 was 111 (range, 11‐246) weeks. 1329/1489 evaluable patients were SVR12 responders; 1316/1329 maintained SVR until their latest visit. Twelve responders relapsed by (n = 9) or after (n = 3) parent study follow‐up Week 24; one was reinfected. Relapse occurred in 3/842 (0.4%) and 9/487 (2%) responders treated with interferon‐free or interferon‐containing regimens, respectively. Hepatic disease progression and new hepatocellular carcinoma were diagnosed in 15 and 23 patients, respectively. Among non‐responders, emergent non‐structural protein‐5A (NS5A) and ‐3 (NS3) substitutions were replaced by wild‐type sequences in 27/157 (17%) and 35/47 (74%) patients, respectively.

Conclusions

SVR12 was durable in 99% of recipients of daclatasvir‐based regimens. Hepatic disease progression and new hepatocellular carcinoma were infrequent. Emergent NS5A substitutions persisted longer than NS3 substitutions among non‐responders.