[Dynamic changes of locus coeruleus damage in Parkinson's disease-like mice induced by paraquat]

Objective: To observe the dynamic changes of brainstem locus coeruleus (LC) damage in Parkinson' s disease (PD) -like mice by paraquat (PQ) . Methods: In October 2019, 36 male C57BL/6 mice were randomly divided into the exposure group and the control group, with 18 mice in each group. The mice in the exposure group were given intraperitoneal injection of 15 mg/kg PQ, and the mice in the control group were given intraperitoneal injection of 0.9% saline, twice a week for 8 weeks. Neurobehavioral changes (pole climbing test, swimming test, open field test, tail hanging test, high plus maze test and water maze test) were observed at 4 weeks, 6 weeks and 8 weeks, respectively, and the changes of motor ability, emotion and cognitive function were evaluated. The brain tissue of mice were taken and stained with Hematoxylin-Eosin (HE) to observe the pathological changes of LC. Nissl staining was used to detect the changes of neuronal Nissl bodies in LC. Immunohistochemistry (IHC) staining was used to detect the expression of neuron nuclear antigen (NeuN) , dopamine (DA) neurons and norepinephrine (NE) neuron markers tyrosine hydroxylase (TH) , α-synuclein (α-syn) in substantia nigra (SN) and LC. The expression levels of NeuN, TH and α-syn in the midbrain and brainstem were detected by Western blotting. TUNEL staining was used to detect neuronal apoptosis in LC. Results: Compared with the 4th week of PQ exposure group, the time of pole climbing and swimming immobility were gradually increased, the ratio of open arm residence time of high plus maze test and the number of times of the platform and the residence time of platform quadrant in water maze test were gradually decreased (P<0.05) in the exposure group with the progress of exposure time. The results of HE and Nissl staining showed that the neurons in LC gradually arranged loosely, the nucleus were deeply stained, the cytoplasm was pyknosis, and the number of Nissl bodies gradually decreased (P<0.05) in the exposure group with the progress of exposure time. IHC results showed that the number of NeuN and TH positive cells in SN and LC of mice were gradually decreased, and the positive expression of α-syn was gradually increased (P<0.05) in the exposure group with the progress of exposure time. Western blotting results showed that the expression levels of NeuN and TH in the midbrain and brainstem were gradually decreased, and the expression level of α-syn was gradually increased (P<0.05) in the exposure group with the progress of exposure time. TUNEL staining showed that the apoptosis rates of neurons in LC were gradually increased (P<0.05) in the exposure group with the progress of exposure time. Conclusion: PQ induces progressive damage in the LC area of PD-like mice, which may be caused by the abnormal accumulation of pathological α-syn in the LC area.

[Preliminary study on time-dependent changes of intestinal tract and brain-gut axis in mice model of Parkinson's disease induced by paraquat]

Objective: To observe the intestinal time-dependent changes in Parkinson's disease (PD) mouse model constructed by intraperitoneal injection of paraquat (PQ) and to establish the brain-gut axis connection initially. Methods: In October 2019, 48 mice were randomly divided into treated group and control groups: treated 4-week (P-4) group, treated 6-week (P-6) group, treated 8-week (P-8) group, control 4-week (C-4) group, control 6-week (C-6) group, and control 8-week (C-8) group. The treated group was injected with 15 mg/kg PQ solution and the control group was injected with 0.9% saline (0.2 ml/20 g) by intraperitoneal injection twice a week. After the initial state (0 weeks) and the treatment at the end of 4, 6 and 8 weeks, the mood changes and motor functions of mice were assessed by neurobehavioral tests (open field test, pole climbing test, tail suspension test and elevated plus maze test) . And the number of fecal pellets for 1 h and water content were calculated to assess the functional status of the gastrointestinal tract. Western blotting experiments were performed to detect the expression levels of α-synuclein (α-syn) and tyrosine hydroxylase (TH) in the nigrostriatal region of the mouse brain, the tight junction markers zonula occludens-1 (ZO-1) and Occludin, the inflammatory markers of integrin αM subunit (CD11b) , inducible nitric oxide synthase (iNOS) , high mobility group box 1 (HMGB1) , interleukin-1β (IL-1β) , and the neuronal markers βⅢ-tubulin and α-syn protein in the colon.Immunohistochemical staining was performed to detect the expression levels of colonic tight junction proteins ZO-1 and Occludin. Immunofluorescence staining was performed to detect the expression levels of TH in the substantia nigra region of the midbrain, and the co-localization of colonic intestine neuronal marker (βⅢ-tubulin) and Ser129 α-syn in the colonic. Results: Compared with the initial state (0 weeks) and C-8 group, mice in the P-8 group had significantly higher pole climbing test scores and resting time, and significantly lower total active distance, mean active speed, percentage of open arm entry and 1 h fecal instances (P<0.05) . After poisoning, the 1 h fecal water content of model mice first increased and then decreased, the P-4 and P-6 groups were significantly higher than the simultaneous point control group, and the P-8 groups were significantly lower than the initial state (P<0.05) . Compared with control, P-4 and P-6 groups, the expression levels of ZO-1 and Occludin in the P-8 group were significantly decreased (P<0.05) . Compared with control group, the expression levels of CD11b and IL-1β in the P-4 group were significantly increased (P<0.05) . Compared with control and P-4 group, the expression levels of CD11b, iNOS, HMGB1 and IL-1β in the P-6 and P-8 groups were significantly increased (P<0.05) . Compared with the control and P-4 groups, the expression levels of βⅢ-tubulin in the colon of mice in the P-8 group were significantly decreased, and the expression levels of α-syn and Ser129 α-syn were significantly increased (P<0.05) . The expression level of Ser129 α-syn in the colon of model mice was negatively correlated with the expression level of βⅢ-tubulin (r(s)=-0.9149, 95%CI: -0.9771--0.7085, P<0.001) . Ser129 α-syn and βⅢ-tubulin co-localization in the colonic intermuscular plexus region increased gradually with the time of exposure. Compared with the control, P-4 and P-6 groups, the expression level of TH in the nigrostriatal region of the brain was significantly decreased, and the expression levels of α-syn and Ser129 α-syn were significantly increased in the P-8 group (P<0.05) . Correlation analysis showed that the relative expression level of Ser129 α-syn in the nigrostriatal region of the brain was negatively correlated with the expression level of TH in the model mice (r(s)=-0.9716, 95% CI: -0.9925--0.8953, P<0.001) . Conclusion: The PD mouse model is successfully established by PQ, and the intestinal function of the model mice is reduced in a time-dependent manner. And on this basis, it is preliminary determined that the abnormal aggregation of α-syn may be an important substance connecting the brain-gut axis.

Explainable deep neural network for echocardiography view classification

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Science and Technology, Taiwan

Background

Deep neural network may assist echocardiography interpretation in several tasks; however, the lack of expandability hindered its broader application since physicians couldn’t realize the rationale of interpretation clearly and comfortably.

Method

Retrospectively, we manually annotated 26,465 transthoracic echocardiography images into 29 classes for model development in 4:1 ratio as training and validation datasets. We added an autoencoder component into our model, adapted from capsule net, for view-classifying to deconvolute the feature maps of last layer as decoder for human interpretation. The performance of view classification was measured in accuracy and confusion matrix, and the interpretability of model were assessed by cardiologist.

Result

After appropriate model training, the accuracy of our model achieved averaged 98.2% for echocardiography view classification, ranged from lowest 80.0% in suprasternal view to 100% of several more common view in validation dataset. The successful deconvolution of feature map to reconstruct images showed essential independent components of echocardiography view and could be interpretated by cardiologist and clinical physicians.

Conclusion

With the use of autoencoder in model for echocardiography view classification showed maintainable good performance in accuracy and facilitated clinical interpretation to enhance its reliability. Abstract Figure. Model architecture and performance  Abstract Figure. Example of explaniable deconvolution

[Value of purple sign for predicting rebleeding events in cirrhotic patients following endoscopic selective varices devascularization]

OBJECTIVE

To assess the value of the purple sign for predicting long-term rebleeding events in cirrhotic patients following endoscopic selective varices devascularization.

METHODS

We retrospectively analyzed the clinical data of 97 patients with liver cirrhosis, who had a history of gastroesophageal variceal bleeding and underwent endoscopic selective varices devascularization. Thirty-two of the patients showed purple sign after endoscopic treatment. We used propensity score matching (PSM) to minimize the selection bias of the patients (purple sign vs no purple sign) and reduce the intergroup differences of clinical characteristics. The primary outcome measure of this study was cumulative rebleeding events after endoscopic selective varices devascularization.

RESULTS

The 1-year rebleeding rate (27.0% vs 36.7%) or 6-month rebleeding rate (10.9% vs 26.9%) following endoscopic treatment was not significantly different between the purple sign group and no purple sign group before PSM (P=0.2385). But after PSM, the 1-year rebleeding rate (28.2% vs 56.4%) and 6-month rebleeding rate (5.0% vs 37.0%) were significantly lower in the purple sign group than in the no purple sign group (P=0.0304).

CONCLUSIONS

The presence of purple sign indicates a lower risk of rebleeding after endoscopic treatment of cirrhotic gastroesophageal varices and a potentially favorable treatment response after endoscopic therapy, thus providing a clinical indicator for stratification of the patients for sequential endoscopic sessions.

Multi-task deep learning network to predict future macrovascular invasion in hepatocellular carcinoma

BACKGROUND

Models predicting future macrovascular invasion in hepatocellular carcinoma are constructed to assist timely interventions.

METHODS

A total of 366 HCC cases were retrospectively collected from five Chinese hospitals between April 2007 and November 2016: the training dataset comprised 281 patients from four hospitals; the external validation dataset comprised 85 patients from another hospital. Multi-task deep learning network-based models were constructed to predict future macrovascular invasion. The discrimination, calibration, and decision curves were compared to identify the best model. We compared the time to macrovascular invasion and overall survival using the best model and related image heterogeneity scores (H-score). Then, we determined the need for a segmentation subnet or the replacement deep learning algorithm by logistic regression in screening clinical/radiological factors. Finally, an applet was constructed for future application.

FINDINGS

The best model combined clinical/radiological factors and radiomic features. It achieved best discrimination (areas under the curve: 0·877 in the training dataset and 0·836 in the validation dataset), calibration, and decision curve. Its performance was not affected by the treatments and disease stages. The subgroups had statistical significance for time to macrovascular invasion (training: hazard ratio [HR] = 0·073, 95% confidence interval [CI]: 0·032-0·167, p < 0·001 and validation: HR = 0·090, 95%CI: 0·022-0·366, p < 0·001) and overall survival (training: HR = 0·344, 95%CI: 0·246-0·547, p < 0·001 and validation: HR = 0·489, 95%CI: 0·279 - 0·859, p = 0·003). Similar results were achieved when the patients were subdivided by the H-score. The subnet for segmentation and end-to-end deep learning algorithms improved the performance of the model.

INTERPRETATION

Our multi-task deep learning network-based model successfully predicted future macrovascular invasion. In high-risk populations, besides the current first-line treatments, more therapies may be explored for macrovascular invasion.

Association between isolated diastolic hypertension and cardiovascular events: a systematic review and meta-analysis of prospective cohorts

Background

Isolated diastolic hypertension (IDH) is a subtype of hypertension, which is defined as systolic blood pressure (SBP) &lt;140 mmHg and diastolic blood pressure (DBP) ≥90 mmHg by 2018 European Society of Cardiology (ESC) guideline and 2019 National Institute for Health and Care Excellent (NICE). Whereas some previous studies have demonstrated the significant association between IDH and cardiovascular (CV) events, some have not.

Purpose

To assess the association between IDH and the risk of CV events, CV mortality, and all-cause mortality.

Methods

We conducted a systematic search for publications using Medline, Embase, and the Cochrane Library from inception through March 2021 for prospective cohort studies exploring the association between IDH and CV events, CV mortality, and all-cause mortality. Relative risks (RR) or hazard ratios were extracted from the selected studies. Random effect models with inverse variance weighting were used to calculate the pooled RR and 95% confidence interval (CI). The primary outcome was a composite of total CV events including CV mortality. The secondary outcomes were CV mortality and all-cause mortality. We defined the IDH as SBP &lt;140 mmHg and DBP ≥90 mmHg, reference group as BP less than 140/90mmHg.

Results

Overall, 15 studies were identified including 1049587 participants (5.5% IDH). For the primary outcome, IDH was significantly associated with risk of CV events (RR, 1.40 [95% CI, 1.18–1.66], p&lt;0.001). The increased risk of CV events was also observed in subgroup analyses based on age (less or more than 50) and sex. However, in further stratified analysis based on geographical region, only the Asia population showed a significant association with increased risk of CV events, whereas results were null in Europe and North America populations. For the secondary outcomes, IDH was significantly associated with increased CV mortality (RR [95% CI], 1.41 [1.12–1.78], p&lt;0.001) but not with all-cause mortality (RR [95% CI], 1.13 [0.86–1.48], p=0.378). The sensitivity analysis showed the overall results did not vary significantly after exclusion of any one study.

Conclusions

IDH is associated with increased risk of CV events and CV mortality. Further, more large-scale prospective epidemiological cohorts are needed to confirm our conclusion.

Funding Acknowledgement

Type of funding sources: None. Primary outcomeSecondary outcomes

Whole-genome resequencing reveals genetic structure and introgression in Pudong White pigs

Pudong White (PDW) pigs, historically originating from Shanghai, are the only Chinese indigenous pigs characterised by their completely white coats, with the exception of Rongchang pigs. However, there is limited information concerning their overall genetic structure or relationship with other breeds, especially the East Chinese (ECN) and European pigs. To uncover the genetic structure, selection signatures, and potential exotic introgression in PDW pigs, we sampled 15 PDW pigs using whole-genome sequencing (~20×). We then conducted in-depth population genetic analyses in 320 pigs from 27 global pig groups, namely, European wild boars, Chinese wild boars, and outgroup. Neighbour-joining tree and principal component analysis confirmed that PDW pigs belonged to the ecotype of ECN pigs. Both f3, D-statistics, and structure analysis showed that PDW pigs shared apparent alleles with Large White (LW) pigs. Three statistics, rIBD, a haplotype heat map and copy number variation, further indicated that PDW pigs shared apparent alleles with LW pigs at the KIT Proto-Oncogene, Receptor Tyrosine Kinase (KIT) and PARG-MARCHF8 loci, suggesting that the lineage of European pigs in PDW originated from LW pigs. After further detecting the KIT mutations in different pig breeds, PDW was confirmed to have the same duplication region 1, duplication region 2, and the splicing mutation on intron 17 of KIT as LW pigs that determine the white coat colour phenotype in European white pigs. We hypothesised that LW pigs were imported to China ∼110-160 years ago according to the admixture time estimate and then crossed with ECN pigs, resulting in the introgression of the KIT alleles that produce the white coat colour phenotype in the PDW pig breed. To our knowledge, this study presents the first thorough description of the genetic structure of PDW pigs via whole-genome resequencing data; moreover, the results provide a basis for the national project for the conservation of this unique Chinese local population.

Liver DCE-MRI registration based on sparse recovery of contrast agent curves

PURPOSE

Dynamic contrast-enhanced MRI (DCE-MRI) registration is a challenging task because of the effect of remarkable intensity changes caused by contrast agent injections. Unrealistic deformation usually occurs by using traditional intensity-based algorithms. To alleviate the effect of contrast agent on registration, we proposed a DCE-MRI registration strategy and investigated the registration performance on the clinical DCE-MRI time series of liver.

METHOD

We reconstructed the time-intensity curves of the contrast agent through sparse representation with a predefined dictionary whose columns were the time-intensity curves with high correlations with respect to a preselected contrast agent curve. After reshaping 1D-reconstructed contrast agent time-intensity curves into a 4D contrast agent time series, we aligned the original time series to the reconstructed contrast agent time series through traditional free-form deformation (FFD) registration scheme combined with a residual complexity (RC) similarity and an iterative registration strategy. This study included the DCE-MRI time series of 20 patients with liver cancer.

RESULTS

Qualitatively, the time-cut images and subtraction images of different registration methods did not obviously differ. Quantitatively, the mean (standard deviation) of temporal intensity smoothness of all the patients achieved 54.910 (18.819), 54.609 (18.859), and 53.391 (19.031) in FFD RC, RDDR, Zhou et al.'s method and the proposed method, respectively. The mean (standard deviation) of changes in the lesion volume were 0.985 (0.041), 0.983 (0.041), 0.981 (0.046), and 0.989 (0.036) in FFD RC, RDDR, Zhou et al.'s method and the proposed method.

CONCLUSION

Our proposed method would be an effective registration strategy for DCE-MRI time series, and its performance was comparable with that of three advanced registration methods.

Co-sparse reduced-rank regression for association analysis between imaging phenotypes and genetic variants

MOTIVATION

The association analysis between genetic variants and imaging phenotypes must be carried out to understand the inherited neuropsychiatric disorders via imaging genetic studies. Given the high dimensionality in imaging and genetic data, traditional methods based on massive univariate regression entail large computational cost and disregard many-to-many correlations between phenotypes and genetic variants. Several multivariate imaging genetic methods have been proposed to alleviate the above problems. However, most of these methods are based on the l1 penalty, which might cause the over-selection of variables and thus mislead scientists in analyzing data from the field of neuroimaging genetics.

RESULTS

To address these challenges in both statistics and computation, we propose a novel co-sparse reduced-rank regression model that identifies complex correlations in a dimensional reduction manner. We developed an iterative algorithm based on a group primal dual-active set formulation to detect simultaneously important genetic variants and imaging phenotypes efficiently and precisely via non-convex penalty. The simulation studies showed that our method achieved accurate and stable performance in parameter estimation and variable selection. In real application, the proposed approach successfully detected several novel Alzheimer's disease-related genetic variants and regions of interest, which indicate that our method may be a valuable statistical toolbox for imaging genetic studies.

AVAILABILITY AND IMPLEMENTATION

The R package csrrr, and the code for experiments in this article is available in Github: https://github.com/hailongba/csrrr.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.