Reassessment of the Effect of Transcutaneous Auricular Vagus Nerve Stimulation Using a Novel Burst Paradigm on Cardiac Autonomic Function in Healthy Young Adults

BACKGROUND

Transcutaneous auricular vagus nerve stimulation (taVNS) may modulate cardiac autonomic function. However, the response rate of the traditional tonic paradigm is low, and the results remain inconsistent. A recent pilot study presented a novel burst paradigm to activate the cardiac parasympathetic system, which might offer a new approach to treat cardiac autonomic function. The present study reassessed the effect of burst taVNS on modulating heart rate variability and explored the difference between burst and traditional tonic paradigms.

MATERIALS AND METHODS

Forty-two young adults were recruited for this study. Each participant underwent three types of taVNS with sham (30 sec of stimulation), tonic (25 Hz, 500 μsec), and burst (five pulses at 500 Hz every 200 msec) paradigms, respectively, with simultaneous electrocardiogram recording. One-way analysis of variance, multivariate analysis of variance, and linear regression were used for analysis. Multiple testing was performed using Bonferroni correction.

RESULTS

Both burst and tonic paradigms induced a significant decrease in heart rate, which continued until poststimulation, and increased cardiac parasympathetic activity. Moreover, two parasympathetic system indicators showed significant increase only in burst taVNS. The response rates during burst (35.7%) and tonic (38.1%) stimulations were both higher than that during sham stimulation (11.9%). The response to taVNS showed parameter specificity with few nonresponders to the tonic paradigm responding to the burst paradigm. The overall response rate increased from 38.1% in tonic taVNS to 54.8% in taVNS using both burst and tonic paradigms. For both burst and tonic responders, baseline cardiac parasympathetic activity was found to be significantly negatively correlated with changes during stimulation.

CONCLUSION

The burst parameter could be used as an alternative strategy for regulating cardiac parasympathetic function by taVNS, which has the potential to be used as a complementary paradigm to traditional tonic taVNS for promoting clinical treatment efficacy.

[Causal relationship between sleep and coronary artery disease: a Mendelian randomization study]

Objective: To understand the causal relationship between sleep and coronary artery disease (CAD). Methods: This study included six genome-wide association parts; five for sleep related traits[sleep duration (continuous variable), long sleep duration (binary variable), short sleep duration (binary variable), early-to-bed/up habit (known as 'morningness') and frequently insomnia] and one for CAD. Heterogeneity in dependent instrument approach was used to assess and to remove the pleiotropic instruments. Generalized summary data-based Mendelian randomization was performed to estimate the causal relationships between sleep related traits and CAD. And a conservative Bonferroni was used for statistical tests. Results: Sleep duration was putatively causal for CAD (OR=0.755, 95%CI: 0.658-0.867, P=6.68E-05). Our results also indicated significant causal effects between both short sleep duration and frequently insomnia on CAD, with ORs as 4.251 (95%CI: 2.396-7.541, P=7.51E-07) and 1.814 (95%CI: 1.346-2.446, P=9.25E-05), respectively. There was no convincing evidence of causality between long sleep duration or morningness with CAD. Conclusions: Our findings suggested that both sleep duration and frequently insomnia played causal roles on CAD, indicating that disease models should include sleep duration and insomnia as potential factors for CAD to develop effective interventions.

[Childhood obesity and coronary artery disease: a Mendelian randomization study]

Objective: To assess the casual effect of childhood obesity on adulthood coronary artery disease (CAD) using Mendelian randomization (MR) method. Methods: Data on BMI of children aged 2-10 years in 2015 were downloaded from Early Growth Genetics Consortium and Genetic Investigation of Anthropometric Traits Consortium. Twenty-seven genetic variants related to children's BMI were selected as instrumental variables (IVs), and the associations between IVs and CAD were extracted from a Meta-analysis of the genome-wide association study of CAD cases published in UK Biobank 2015. We used MR-Egger regression to test whether there was the pleiotropy of the selected SNPs. In the present MR methods, we conducted MR analyses by using mode-based estimate method as primary method for summary-level of associations to estimate the causal association between childhood obesity and CAD. Results: The intercept term estimated for CAD from MR-Egger method suggested that the selected SNPs don't exert pleiotropy with a 95%CI including the null (-0.008-0.018). In addition, we found evidence that support the effect of childhood obesity on CAD risk: a 1 s increase in children BMI (kg/m(2)), and the risk of suffering from CAD in adulthood increased by an average of 37% (OR=1.37, 95%CI: 1.09-1.72). Conclusion: This study provides a causal association between childhood obesity and CAD risk.

Transfusion-related acute lung injury in paediatric surgical patients: a retrospective study

BACKGROUND

Little is known about the occurrence of transfusion-related acute lung injury(TRALI) in Chinese paediatric patients. As such, a retrospective review of medical records from January 2008 to December 2011 was undertaken.

OBJECTIVE

To determine the incidence of TRALI and its risk factors in children (age <14 years).

STUDY DESIGN AND METHODS

All medical records of Sheng Jing Hospital from January 2008 to December 2011 were reviewed retrospectively using the hospital’s record system. Paediatric surgical patients who had been diagnosed clinically with acute lung injury were included. Transfusion data were collected, together with risk factors such as sepsis and aspiration.

RESULTS

In total, 1495 patients were involved in the study. Thirty-five cases were analysed further as they had acute lung injury, pulmonary oedema and respiratory distress. TRALI was confirmed in two of these cases. The average duration of transfusion was found to be significantly longer in patients with TRALI compared with controls, and the percentage of female donors was significantly higher for patients with TRALI.

CONCLUSION

The incidence of TRALI was found to be lower than reported previously, but TRALI is under-recognised, under-reported and undertreated.

Environmental effects of nationwide selenium fertilization in Finland

To study the possible pollution of natural waters by selenium added to agricultural fertilizers, water selenium concentrations were determined in lakes and ground water pools during the year 1992, when the enrichment of fertilizers by selenium had continued for 8 yr. Water samples were preconcentrated by evaporating, and selenium concentrations were analyzed fluorometrically using the dye 2,3-diaminonaphthalene after wet digestion. In lake water samples from 13 lakes, no significant correlations were found between selenium and pH, chlorophyll A, total nitrogen, or phosphorus. Agriculturally affected and nonaffected lakes had no differences in their selenium concentrations. In the lakes that were surrounded by cultivated fields mean water selenium was 83.4 ng/L (range: 75.2-93.4 ng/L, n = 9). Correspondingly, in lakes situated in forests without agricultural surroundings, mean water selenium concentration was 76.5 ng/L (range: 51.2-110 ng/L, n = 3). Only one lake in the close vicinity of a coal power plant had a high water selenium concentration (mean 272 ng/L). In ground water samples, there was a big variation in selenium levels between different pools, the levels varying between 33 and 260 ng/L. This variation may partly be explained by different selenium concentrations of the bedrock and sediments. However, simultaneous increase of total nitrogen, phosphorus, and selenium levels in consecutive samples from some ground water pools indicates leaching of selenium from the fertilizers into the ground water in certain areas.