Whole exome sequencing with a focus on cardiac disease-associated genes in families of sudden unexplained deaths in Yunnan, southwest of China.

OBJECTIVES: To explore the causes of sudden unexpected death (SUD) and to search for high-risk people, whole exome sequencing (WES) was performed in families with SUDs.  METHODS: Whole exome sequencing of 25 people from 14 SUD families were screened based on cardiac disease-associated gene variants, and their echocardiograms and electrocardiograms (ECG) were also examined. The protein function of mutated genes was predicted by SIFT, PolyPhen2 and Mutation Assessor. RESULTS: In the group of 25 people from 14 SUD families, 49 single nucleotide variants (SNVs) of cardiac disease-associated genes were found and verified by Sanger sequencing. 29 SNVs of 14 cardiac disorder-related genes were predicted as pathogens by software. Among them, 7 SNVs carried by two or more members were found in 5 families, including SCN5A (c.3577C > T), IRX4 (c.230A > G), LDB3 (c.2104 T > G), MYH6 (c.3G > A), MYH6 (c.3928 T > C), TTN (c.80987C > T) and TTN (c.8069C > T). 25 ECGs were collected. In summary, 4 people had J-point elevation, 2 people had long QT syndrome (LQTS), 4 people had prolonged QT interval, 3 people had T-wave changes, 3 people had sinus tachycardia, 4 people had sinus bradycardia, 4 people had left side of QRS electrical axis, and 3 people had P wave broadening. Echocardiographic results showed that 1 person had atrial septal defect, 1 person had tricuspid regurgitation, and 2 people had left ventricular diastolic dysfunction. CONCLUSIONS: Of the 14 heart disease-associated genes in 14 SUDs families, there are 7 possible pathological SNVS may be associated with SUDs. Our results indicate that people with ECG abnormalities, such as prolonged QT interval, ST segment changes, T-wave change and carrying the above 7 SNVs, should be the focus of prevention of sudden death.

Postmortem Analysis of 4 Mutation Hotspots of KCNQ1, KCNH2, and SCN5A Genes in Sudden Unexplained Death in Southwest of China.

Long QT syndrome (LQTS) is known to be involved in some sudden unexplained death (SUD) cases. To make clear whether the pathogenic genes of LQTS are involved in SUD in Yunnan province, southwest of China, we examined 4 mutation hotspot segments of KCNQ1, KCNH2, and SCN5A genes in 83 SUD cases using polymerase chain reaction and direct DNA sequencing. Genomic DNA was extracted from paraffin-embedded tissues in 83 cases of sudden cardiac death. One novel homozygous missense variant was identified in exon 3 of KCNQ1, c. 575G>T (p.R192L) in one case. One novel heterozygous missense variant was identified in exon 7 of KCNH2, c.1789T>A (p.Y597N) in 1 case. One novel heterozygous missense variant was identified in exon 7 of KCNH2, c.1800C>A (p.S600R) in 9 cases. In addition, 18 individuals were found to have heterozygous missense variant in exon 7 of KCNH2, c.1801G>A (p.G601S). Our study suggests that some SUDs in Yunnan province may be related with the pathogenic genes of LQTS.

[Changes of adenylate cyclase on cerebral regions related to mophine dependence in rats].

OBJECTIVE: To observe the changes of adenylate cyclase(AC) on cerebral regions related to morphine dependence in rats and investigate the relationship between the enzymological changes and the mechanism of morphine dependence. METHODS: The technique of enzyme-histochemistry was used to detect the variations of AC of special seven cerebral regions including frontalis cortex, lenticula, corpus amygdaloideun, substantia nigra, hippocampus, periaqueductal gray and locus coerleus in morphine dependent rats. The enzymological changes were observed by optical microscope. Changes of gray degree of these cerebral regions were also observed by using the image analysis system. RESULTS: Compared with those in control group, the contents of AC in morphine dependent groups were increased. CONCLUSION: The contents of AC are increase in those regions. The mechanism of morphine dependence close related to the increasing of AC. The correlation of the mechanism of morphine dependence and up-regulation of AC/cAMP-PKA system is discussed.

The comparison of methods to identify the presence of fibrocytes in formalin-fixed, paraffin-embedded archival cardiac tissue with coronary heart disease.

The purpose of this study was to find the optimal technical approach to identify the presence of fibrocytes in formalin-fixed, paraffin-embedded archival cardiac tissue with CHD (coronary heart disease). Using the coexpression markers CD45 and αSMA, the presence of fibrocytes was examined by three different methods, including double immunohistochemistry staining, combination labeling of immunohistochemistry and immunofluorescence and double immunofluorescence labeling. Double immunohistochemistry staining was very difficult to identify the CD45(+)/αSMA(+) fibrocytes. Although combination staining of immunohistochemistry and immunofluorescence has made it possible to evaluate the co-localization of CD45 and αSMA in the fibrocytes, this method was prone to produce many false positive cells. In contrast, CD45(+)/αSMA(+) fibrocytes could be clearly recognized by double immunofluorescence labeling. In conclusion, double immunofluorescence labeling is the optimal technical approach to identify the presence of fibrocytes in routinely processed cardiac tissue with CHD.

Fibrocytes are associated with the fibrosis of coronary heart disease.

Fibrocytes contribute significantly to fibrosis in many cardiac diseases. However, it is not clear whether fibrocytes are associated with the fibrosis in coronary heart disease (CHD). The aim of this study was to determine whether fibrocytes are involved in cardiac fibrosis in CHD. We identified the presence of fibrocytes in CHD heart by immunofluorescence and confocal microscopy, examined the collagen volume fraction by Masson's Trichrome staining, and evaluated the correlation between fibrocytes and cardiac fibrosis. In conjunction, we examined the location of CXCL12, a homing factor and specific ligand for CXCR4, by immunohistochemistry. Fibrocytes were identified in 26 out of 27 CHD hearts and in 10 out of 11 normal hearts. Combinations, including CD34/αSMA, CD34/procollagen-I, CD45/αSMA, CXCR4/procollagen-I and CXCR4/αSMA, stained significantly more fibrocytes in CHD hearts as compared with those in normal hearts (p<0.05). There were positive correlations between the collagen volume fraction and the amount of fibrocytes (r=0.558; p=0.003<0.01) and between the number of CXCR4(+) fibrocytes and the CXCL12(+) cells (r=0.741; p=0.000<0.01) in CHD hearts. Based upon these findings, we conclude that fibrocytes, likely recruited through the CXCR4/CXCL12 axis, may contribute to the increase in the fibroblast population in CHD heart.

Extracorporeal cardiac shock wave therapy ameliorates myocardial fibrosis by decreasing the amount of fibrocytes after acute myocardial infarction in pigs.

OBJECTIVES: Extracorporeal shock wave (SW) therapy ameliorates cardiac remodeling after acute myocardial infarction (AMI). However, it remains to be examined whether and how SW therapy ameliorates myocardial fibrosis after AMI. Fibrocytes are associated with myocardial fibrosis. Thus, we examined whether SW therapy ameliorates myocardial fibrosis and whether fibrocytes are associated after AMI in pigs. MATERIALS AND METHODS: AMI was created by coronary embolism. Twenty-five pigs were divided into three groups: AMI+SW group (AMI with SW therapy, n=15), AMI group (without SW therapy, n=5), and sham+SW group (SW therapy without AMI, n=5). The collagen area fraction was examined by Masson's trichrome staining. The presence of fibrocytes was identified by immunofluorescence and confocal microscopy. The location of CXCL12 was examined by immunohistochemistry. RESULTS: Compared with the AMI group, the AMI+SW group showed significantly ameliorated myocardial fibrosis in terms of collagen area fraction (27.21±8.13 vs. 10.13±4.96, P<0.05) and reduced fibrocytes (CD34/α-smooth muscle actin: 35.40±11.72 vs. 12.27±7.71, P<0.05; CXCR4/α-smooth muscle actin: 40.80±8.96 vs. 16.54±6.38, P<0.05). There were positive correlations between the collagen area fraction and the number of fibrocytes (r=0.936; P<0.05) and between the number of CXCR4 fibrocytes and the SDF-1/CXCL12 cells (r=0.802; P<0.05) in the three groups. CONCLUSION: The results show that SW therapy ameliorates myocardial fibrosis after AMI in pigs, which is associated with the decreased amount of fibrocytes.