Long-term prognostic value of major and minor ECG abnormalities in latent Keshan disease with suspect chronic Keshan disease

Integrative analysis of multiomics data identifies selenium-related gene ALAD associating with keshan disease

Keshan disease is an endemic fatal dilated cardiomyopathy that can cause heart enlargement, heart failure, and cardiogenic death. Selenium deficiency is considered to be the main cause of Keshan disease. However, the molecular mechanism underlying Keshan disease remains unclear. Our whole-exome sequencing from 68 patients with Keshan disease and 100 controls found 199 candidate genes by gene-level burden tests. Interestingly, using multiomics data, the selenium-related gene ALAD (δ-aminolevulinic acid dehydratase) was the only candidate causative gene identified by three different analysis approaches. Based on single-cell transcriptome data, ALAD was highly expressed in cardiomyocytes and double mutations of human ALAD dramatically reduced its enzyme activity in vitro compared to negative control. Functional analysis of ALAD inhibition in mice resulted in a Keshan phenotype with left ventricular enlargement and cardiac dysfunction, whereas administration of sodium selenite markedly reversed the changes caused by ALAD inhibition. In addition, sodium selenite reversed Keshan phenotypes by affecting energy metabolism and mitochondrial function in mice as shown by the transcriptomic and proteomic data and the ultrastructure of cardiac myocytes. Our findings are the first to demonstrate that the selenium-related gene ALAD is essential for cardiac function by maintaining normal mitochondrial activity, providing strong molecular evidence supporting the hypothesis of selenium deficiency in Keshan disease. These results identified ALAD as a novel target for therapeutic intervention in Keshan disease and Keshan disease-related dilated cardiomyopathy.

Keshan Disease: A Potentially Fatal Endemic Cardiomyopathy in Remote Mountains of China

Keshan disease (KD) as an endemic, highly lethal cardiomyopathy, first reported in northeast China's Keshan County in 1935. The clinical manifestations of patients with KD include primarily congestive heart failure, acute heart failure, and cardiac arrhythmia. Even though some possible etiologies, such as viral infection, fungal infection, microelement deficiency, and malnutrition, have been reported, the exact causes of KD remain poorly known. The endemic areas where KD is found are remote and rural, and many are poor and mountainous places where people are the most socioeconomically disadvantaged in terms of housing, income, education, transportation, and utilization of health services. To date, KD is a huge burden to and severely restricts the economic development of the local residents and health systems of the endemic areas. Although efforts have been made by the government to control, treat, and interrupt disease transmission, the cure for or complete eradication of KD still requires global attention. For this reason, in this review, we systematically describe the etiological hypothesis, clinical manifestations, incidence characteristics, and treatment of KD, to facilitate the better understanding of and draw more attention to this non-representative cardiovascular disease, with the aim of accelerating its elimination.

Risk factors for Keshan disease: a prospective cohort study protocol of gut flora

BACKGROUND

Keshan disease is an endemic cardiomyopathy of undefined causes. Being involved in the unclear pathogenesis of Keshan disease, a clear diagnosis, and effective treatment cannot be initiated. However, the rapid development of gut flora in cardiovascular disease combined with omics and big data platforms may promote the discovery of new diagnostic markers and provide new therapeutic options. This study aims to identify biomarkers for the early diagnosis and further explore new therapeutic targets for Keshan disease.

METHODS

This cohort study consists of two parts. Though the first part includes 300 participants, however, recruiting will be continued for the eligible participants. After rigorous screening, the blood samples, stools, electrocardiograms, and ultrasonic cardiogram data would be collected from participants to elucidate the relationship between gut flora and host. The second part includes a prospective follow-up study for every 6 months within 2 years. Finally, deep mining of big data and rapid machine learning will be employed to analyze the baseline data, experimental data, and clinical data to seek out the new biomarkers to predict the pathogenesis of Keshan disease.

DISCUSSION

Our study will clarify the distribution of gut flora in patients with Keshan disease and the abundance and population changes of gut flora in different stages of the disease. Through the big data platform analyze the relationship between environmental factors, clinical factors, and gut flora, the main factors affecting the occurrence of Keshan disease were identified, and the changed molecular pathways of gut flora were predicted. Finally, the specific gut flora and molecular pathways affecting Keshan disease were identified by metagenomics combined with metabonomic analysis.

TRIAL REGISTRATION

ChiCTR1900026639. Registered on 16 October 2019.

Network Analysis of Se-and Zn-related Proteins in the Serum Proteomics Expression Profile of the Endemic Dilated Cardiomyopathy Keshan Disease

Keshan disease (KD) is an endemic cardiomyopathy with high mortality. Selenium (Se) and zinc (Zn) deficiencies are closely related to KD. The molecular mechanism of KD pathogenesis is still unclear. There are only few studies on the interaction of trace elements and proteins associated with the pathogenesis of KD. In this study, isobaric tags for relative and absolute quantitation (iTRAQ)-coupled two-dimensional liquid chromatography tandem mass spectrometry (2DLC-MS/MS) technique analysis was used to analyze the differential expression of proteins from serum samples. Comparative Toxicogenomics Database (CTD) was used to screen Se- and Zn-associated proteins. Then, pathway and network analyses of Se- and Zn-associated proteins were constituted by Cytoscape ClueGO and GeneMANIA plugins. One hundred and five differentially expressed proteins were obtained by 2DLC-MS/MS, among them 19 Se- and 3 Zn-associated proteins. Fifty-two pathways were identified from ClueGO and 1 network from GeneMANIA analyses. The results showed that Se-associated proteins STAT3 and MAPK1 and Zn-associated proteins HIF1A and PARP1, the proteins involved in HIF-1 signaling pathway and apoptosis pathway, may play significant roles in the pathogenesis of KD. The approach of this study would be also beneficial for further dissecting molecular mechanism of other trace element-associated disease.

Prediction of co-expression genes and integrative analysis of gene microarray and proteomics profile of Keshan disease

Keshan disease (KD) is a kind of endemic cardiomyopathy which has a high mortality. However, molecular mechanism in the pathogenesis of KD remains poorly understood. Serum samples were collected from 112 KD patients and 112 normal controls. Gene microarray was used to screen differently expressed genes. Genevestigator was applied to forecast co-expression genes of significant gene. iTRAQ proteomics analysis was used to verify significant genes and their co-expression genes. GO, COG, IPA and STRING were applied to undertake function categorization, pathway and network analysis separately. We identified 32 differentially expressed genes; IDH2, FEM1A, SSPB1 and their respective 30 co-expression genes; 68 differential proteins in KD. Significant proteins were categorized into 23 biological processes, 16 molecular functions, 16 cellular components, 15 function classes, 13 KD pathways and 1 network. IDH2, FEM1A, SSBP1, CALR, NDUFS2, IDH3A, GAPDH, TCA Cycle II (Eukaryotic) pathway and NADP repair pathway may play important roles in the pathogenesis of KD.

Preliminary quantitative proteomics analysis in chronic and latent Keshan disease by iTRAQ labeling approach

Keshan disease is a congestive cardiomyopathy. Dietary selenium deficiency combined with additional stressors are recognized to cause the cardiomyopathies. In this study, clinical condition of individuals with different subtypes including chronic and latent were analyzed. ECG abnormalities, chest radiography, echocardiography and blood selenium concentration were assessed. Subsequently, in effort to uncover proteins that were reliably changed in patients, isobaric tags for absolute and relative quantitation technology was applied. Bioinformatics analysis of the differentially expressed proteins were performed by means of Gene Ontology classification, KEGG pathway, and Ingenuity Pathway Analysis. ELISA experiment was used to detect the interesting proteins. As a result, chronic patients showed more EGC abnormalities compared to Latent. All patients had low blood selenium level. Proteomics data revealed 28 differentially expressed proteins. By ELISA variation, LGALS3BP was increased in chronic patients. PZP was elevated specially in latent patients. The above results might be beneficial for further biomarkers discovery and Keshan disease pathological mechanism study.

Roles of Glycoproteins in the Diagnosis and Differential Diagnosis of Chronic and Latent Keshan Disease

We aimed to explore the roles of glycoproteins in the pathogenesis of chronic and latent Keshan disease (CKD and LKD), and screen the lectins as indicators of significant differences in glycoproteins of KD saliva and serum. Blood and saliva were collected from 50 CKD, 50 LKD patients and 54 normal individuals. Saliva and serum lectin microarrays and saliva and serum microarrays were used to screen and verify the differences in the levels of lectin among the three groups. In the male saliva lectin microarray, Solanum tuberosum (potato) lectin (STL) and other 9 lectins showed differences between CKD and normal; STL and other 9 lectins showed differences between LKD and normal; Aleuria aurantia lectin (AAL) and other 15 lectins showed differences between CKD and LKD. In the female saliva microarray, Griffonia (Bandeiraea) simplicifolia lectin I (GSL-I) and other 9 lectins showed differences between CKD and normal; STL and other 7 lectins showed differences between LKD and normal; Maackia amurensis lectin I (MAL-I) and Triticum vulgaris (WGA) showed difference between CKD and LKD. In the male serum lectin microarray, Psophocarpus tetragonolobus lectin I (PTL-I) and other 16 lectins showed differences between CKD and normal; Ulexeuropaeus agglutinin I (UEA-I) and other 9 lectins showed differences between LKD and normal; AAL and other 13 lectins showed differences between CKD and LKD. In the female serum lectin microarray, WGA and other 13 lectins showed differences between CKD and normal; Euonymus europaeus lectin (EEL) and other 6 lectins showed differences between LKD and normal; MAL-I and other 14 lectins showed differences between CKD and LKD. Carbohydrate chain GlcNAc and α-Gal may play crucial roles in the pathogenesis of KD. STL may be considered the diagnostic biomarker for male CKD and LKD, while WGA may be useful in distinguishing between the two stages. STL may be considered the diagnostic biomarker for female LKD.