Hypertrophic cardiomyopathy(HCM)is the most common type of primary cardiomyopathy that causes sudden cardiac death in adolescents and athletes.With over 1 million HCM patients,China has the largest population of HCM patients in the world,and the total number of cases is increasing year on year.Myocardial fibrosis is the most important histopathological characterization in HCM and is regarded as the primary cause of malignant ventricular arrhythmia,cardiac remodeling,and heart failure.At present,cardiac magnetic resonance imaging(MRI)serves as the gold-standard imaging modality for noninvasive evaluation of myocardial fibrosis.Several techniques,such as late gadolinium enhancement and T1 mapping,are showing considerable promise for potential applications.These techniques have emerged as viable imaging approaches to the elucidation of HCM tissue characterization.They are also helpful in predicting the long-term prognosis of patients.Herein,we summarized recent advances in using cardiac MRI to assess myocardial fibrosis in HCM from four perspectives,including late gadolinium enhancement,T1 mapping,T1p mapping,and MRI-based radiomics and machine learning models.

8-prenylnaringenin (8-PN) is a potent estrogen with high medicinal values. It also serves as an important precursor for many prenylated flavonoids. Microbial synthesis of 8-PN is mainly hindered by the low catalytic activity of prenyltransferases (PTS) and insufficient supply of precursors. In this work, a SfN8DT-1 from Sophora flavescens was used to improve the efficiency of (2S)-naringenin prenylation. The predicted structure of SfN8DT-1 showed that its main body is comprised of 9 α-helices and 8 loops, along with a long side chain formed by nearly 120 amino acids. SfN8DT-1 mutants with different side-chain truncated were tested in Saccharomyces cerevisiae. A mutant expressing the truncated enzyme at K62 site, designated as SfND8T-1-t62, produced the highest 8-PN titer. Molecular docking of SfN8DT-1-t62 with (2S)-naringenin and dimethylallyl diphosphate (DMAPP) showed that K185 was a potentially crucial residue. Alanine scanning within a range of 0.5 nm around these two substrates showed that the mutant K185A may decrease its affinity to substrates, which also indicated K185 was a potentially critical residue. Besides, the mutant K185W enhanced the affinity to ligands implied by the simulated saturation mutation, while the saturated mutation of K185 showed a great decrease in 8-PN production, indicating K185 is vital for the activity of SfN8DT-1. Subsequently, overexpressing the key genes of Mevalonate (MVA) pathway further improved the titer of 8-PN to 31.31 mg/L, which indicated that DMAPP supply is also a limiting factor for 8-PN synthesis. Finally, 44.92 mg/L of 8-PN was produced in a 5 L bioreactor after 120 h, which is the highest 8-PN titer reported to date.
Dimethylallyltranstransferase/metabolism* ; Flavonoids/metabolism* ; Molecular Docking Simulation ; Prenylation ; Saccharomyces cerevisiae/metabolism* ; Sophora/metabolism*

Objective:To investigate the clinical and cardiac magnetic resonance (CMR) characteristics of heart involvement in patients with Fabry disease (AFD).Methods:From January 2018 to March 2021, eight AFD patients [3 males and 5 females, mean age (50±11) years old, range 26-60 years old] confirmed by genetic testing or pathology in Fuwai Hospital were retrospectively included in this study. At the same time, sixteen patients with hypertrophic cardiomyopathy (HCM) [6 males and 10 females, mean age (46±15) years old] and 16 healthy individuals [6 males and 10 females, mean age (51±11) years old] were included as controls. The clinical baseline data and CMR data of the patients were collected and analyzed. The CMR data were analyzed using the software CVI42, with the corresponding parameters automatically generated. One-way ANOVA or Kruskal-Wallis test was used to compare the differences in the parameters among the three groups. Independent-samples t test, Fisher precise test or Mann-Whitney U test were used for the comparison between each two groups. Results:Statistically significant difference was found in renal insufficiency between the HCM group and the AFD group; No other significant difference was found in other clinical factors and ECG results (all P>0.05). CMR results showed that in the AFD group, there were 5 cases with symmetric or roughly symmetric hypertrophy, and 3 with asymmetric hypertrophy. The late gadolinium enhancement (LGE) showed myocardial enhancement in 5 patients, mainly presenting as multiple intermural enhancement, and partially as local subendocardial enhancement. In the HCM group, fourteen cases suffered mainly asymmetric ventricular septal thickening, with or without thickening of other parts of left ventricular wall; and 2 cases had thickening of middle and distal part of the left ventricle. The LGE showed myocardial enhancement in 14 patients, which manifested as focal or patchy enhancement in hypertrophic myocardium, including focal enhancement in the right ventricular insertion of ventricular septum (more common) and subendocardial enhancement in the middle and far segments of left ventricle. Statistically significant difference was found in the differences between the left atrial anterior posterior diameter, the maximum wall thickness of left ventricular, the left ventricular myocardial mass index (LVMI) and the native T 1 value among the three groups (all P<0.001). However, there was no statistically significant difference in the left atrial anterior posterior diameter and the maximum wall thickness of left ventricular between AFD group and HCM group ( P>0.05). The LVMI in AFD group was higher than that in healthy group and HCM group (all P<0.05). Significant difference was found in the native T 1 value among the three groups, with the native T 1 value of the AFD group [(1 177.4±46.0) ms] was significantly lower than that of the healthy group [(1 244.5±34.3) ms] and the HCM group [(1 278.8±41.6) ms], with ( F=13.10, P<0.001). Conclusions:The clinical characteristics of AFD and HCM are quite similar. When AFD is suspected, CMR imaging should be the first choice for imaging examination. Especially, T 1 mapping imaging can provide important information for the diagnosis of AFD.

To construct PTEN/PLGA-(HE)10-MAP nanoparticles, which encapsulated PTEN plasmid DNA and combined with the pH-responsive cell-penetrating peptides (CPPs), and to investigate their effects of gene delivery and anti-tumor targets in vitro. Poly (lactic-co-glycolic acid) (PLGA) nanoparticles loaded with PTEN plasmid DNA were prepared by double emulsification-solvent evaporation method. PTEN/PLGA-(HE)10-MAP nanoparticles were prepared by coupling the histidine-glutamic acid-model amphipathic peptide nanocomplex [(HE)10-MAP] to the surface through amide condensation reaction. Particle size, Zeta potential, encapsulation rate and drug loading were tested to characterize the nanoparticles. By analyzing the cytotoxicity, cellular uptake, targeted transfection of eukaryotic expression plasmids and anti-tumor cell proliferation, the feasibility as a targeted gene delivery system were evaluated. The particle size of PTEN/PLGA-(HE)10-MAP nanoparticles was (266.5 ± 2.86) nm, with the encapsulation efficiency (80.6 ± 6.11)%. Zeta potentials were -(6.7 ± 0.26) mV, +(0.7 ± 0.22) mV and +(37.5 ± 0.85) mV at pH 7.4, 7.0 and 6.5, respectively. In the cytotoxicity test, the cell survival rates of tumor and normal cells were above 80%.Non-loading PLGA-(HE)10-MAP nanoparticles showed no obvious cytotoxicity. The results of cellular uptake experiments showed that PTEN/PLGA-(HE)10-MAP nanoparticles were more readily taken up by cells.The results of CCK-8 showed that the nanoparticles could pH-specifically inhibit proliferation of tumor cell in vitro.And PTEN/PLGA-(HE)10-MAP nanoparticles may be applied in tumor gene therapy.

A thermosensitive hydrogel system consisting of PLGA-PEG-PLGA hydrogel and Pseudomonas aeruginosa DNA vaccine was constructed and the immune efficacy of the system was evaluated. The PLGA-PEG-PLGA thermosensitive hydrogel containing Pseudomonas aeruginosa DNA vaccine was prepared by a simple physical mixing method. The gelation temperature, cytotoxicity, and release curve in vitro were tested.The degradability of hydrogel in vivo was evaluated. The mice were divided into control group (PBS), hydrogel group (Hydrogel), in vivo-jetPEI/plasmid DNA group (in vivo-jetPEI/pDNA), and hydrogel + in vivo-jetPEI/plasmid group (Gel+in vivo-jetPEI/pDNA). Mice were immunized three times with a ten-day interval. Two weeks after the last immunization, the mice were sacrificed. The proliferation of splenic lymphocytes, serum specific IgG antibodies and IFN-γ in supernatant of splenic lymphocytes were detected. The gelation temperature of PLGA-PEG-PLGA hydrogel was (32 ± 0.5) ℃. There was no obvious toxicity to cells in vitro, and about 80% of plasmid DNA was released after 7 days in vitro. PLGA-PEG-PLGA hydrogel was biodegradable, and degraded almost completely after 15 days in vivo. The spleen lymphocytes proliferated; the levels of specific IgG antibodies and IFN-γ of in vivo-jetPEI/pDNA and Gel+in vivo-jetPEI/pDNA groups increased. The hydrogel could enhance the immune response induced by DNA vaccine.Results suggest that the thermosensitive hydrogel system consisting of PLGA-PEG-PLGA hydrogel and Pseudomonas aeruginosa DNA vaccine is a promising new strategy for the development of PA vaccine.

Objective:To investigate the changes of strains based on feature tracking in patients with hypertrophic obstructive cardiomyopathy (HOCM) after surgical myectomy and the potential factors that influenced post-myectomy global strains.Methods:A total of 27 patients with HOCM who underwent septal myectomy in Fuwai Hospital from June 2014 to July 2017 were retrospectively collected. They all received cardiac MR (CMR) cine acquisitions before and after surgery. Their preoperative and postoperative strain parameters, including radial strain (RS), circumferential strain (CS), and longitudinal strain (LS) of the global left ventricle, septum, and lateral wall, were assessed by feature tracking. Comparisons of pre-myectomy and post-myectomy imaging parameters were performed using paired-samples t-test or Wilcoxon matched-pairs signed-ranks test. Pearson or Spearman correlation analysis and linear regression analysis were utilized to find the correlated factors of postoperative global strains. Results:Compared with preoperative strains, postoperative global LS, septal LS, lateral RS, lateral CS, and lateral LS increased statistically (all P<0.05); postoperative global RS, global CS, and septal CS decreased (all P<0.05); no statistically significant difference was observed in septal RS ( P=0.165). Age at surgery ( r=0.428, P=0.026) and preoperative myocardial maximum ventricular wall thickness ( r=-0.587, P=0.001) were both linearly related to postoperative global RS; the further multivariate stepwise linear regressions showed that only preoperative myocardial maximum ventricular wall thickness might be correlated with postoperative global RS (adjusted R 2=0.287, P=0.002). Only myocardial maximum ventricular wall thickness was linearly related to global CS ( r=0.679, P<0.001) and global LS ( r=0.588, P=0.001), respectively; univariate linear regression revealed that preoperative myocardial maximum ventricular wall thickness might be correlated postoperative global CS (adjusted R 2=0.337, P=0.001) and postoperative global LS (adjusted R 2=0.281, P=0.003), respectively. Conclusions:Cardiac surgery definitely relieves left ventricular outflow tract obstruction and generally improves longitudinal and lateral strains, but a negative impact may occur in global and septal CS and RS. Preoperative maximum ventricular wall thickness may affect postoperative global strains.

Objective: To investigate the feasibility and consistency of four-dimensional flow (4D flow) quantification of pulmonary regurgitation in patients with repaired Tetralogy of Fallot (ToF) by comparing with conventional two-dimensional flow (2D flow) and echocardiography. Methods: Both the 4D flow and 2D flow imaging were acquired with repaired ToF (a total of 21 patients) consecutively on 3.0 T MR scanner from May 2018 to August 2018. Pulmonary flow and regurgitant fraction were measured by a commercial post processing software Circle CVI42. All patients underwent echocardiography within one week after or before MR examination. The inter/intra-observer variability by 2D/4D f1ow and agreement between the two methods were investigated by interclass correlation coefficients (ICC) and Bland-Altman analyses. The agreement between MR and echocardiography were analyzed by weighted Kappa coefficient. The correlation between pulmonary regurgitation and cardiac function was also investigated by Pearson analysis. Results: All patients were included and completed the examinations successfully. Both inter-observer and intra-observer agreement by 4D flow for total forward volume (ICC=0.993, 0.996, respectively, P<0.001), total backward volume (ICC=0.994, 0.997, respectively, P<0.001) and regurgitant fraction (ICC=0.968, 0.985, respectively, P<0.001) were good. The total forward volume, total backward volume and regurgitant fraction measured by 2D flow and 4D flow reached a good agreement (ICC=0.954, 0.913,0.721,respectively,P<0.001). The consistency was good for severity of regurgitation measured by 2D flow (weighted Kappa=0.897, P<0.001) and 4D flow (weighted Kappa=0.710, P=0.001) compared with echocardiography. Significant correlation was found among right ventricular cardiac index(r=0.600, P<0.05), right ventricular end-diastolic volume index(r=0.788, P<0.05), right ventricular end-systolic volume index(r=0.683, P<0.05) and left ventricular end-diastolic volume index(r=0.578, P<0.05), left ventricular end-systolic volume index(r=0.687, P<0.05) with regurgitant fraction measured by 2D flow. Regurgitant fraction measured by 4D flow had a significant correlation with right ventricular cardiac index(r=0.606, P<0.05), right ventricular end-diastolic volume index(r=0.685,P<0.05), right ventricular end-systolic volume index(r=0.534, P<0.05) and left ventricular end-diastolic volume index(r=0.459, P<0.05), left ventricular mass index(r=0.633, P<0.05). Conclusion 4D flow MRI provides highly reproducible measurements of pulmonary flow on morphology and haemodynamics in patients with repaired ToF compared with 2D flow MRI and echocardiography.

This study aimed to construct a DC-targeted aptamer-modified Pseudomonas aeruginosa(PA)DNA vaccine delivery system. The cationic liposome was prepared by ethanol injection method. The cationic liposome loading pVAX1-OprF-VP22(Lip-pOprF-VP22)was prepared by electrostatic adsorption method. The encapsulation efficiency of Lip-pOprF-VP22 with different mass ratios of DOTAP/pDNA on pVAX1-OprF-VP22, cytotoxicity and transfection rate to DC2. 4 in vitro were discussed. The particle size and zeta potential of Lip-pOprF-VP22 with best mass ratio were tested. Aptamer-modified cationic liposome loading pVAX1-OprF-VP22(Apt-Lip-pOprF-VP22)was prepared by post-insertion method. The expression of OprF protein after transfection of DC2. 4 and its effect on the maturation of bone marrow-derived dendritic cells(BMDCs)were detected. Data showed that as the mass ratio of DOTAP/pDNA increased, the encapsulation efficiency of Lip-pOprF-VP22 on pVAX1-OprF-VP22 was gradually increased. When the mass ratio was 5 ∶1, pVAX1-OprF-VP22 was encapsulated well. When Lip-pOprF-VP22 with different mass ratios was applied to DC2. 4 for 24 h or 48 h, the survival rates of DC2. 4 were all above 80%. When the mass ratio of DOTAP/pDNA increased from 2 ∶1 to 10 ∶1, the transfection rate increased first and then decreased. When the mass ratios of DOTAP/pDNA were 4 ∶1 and 5 ∶1, the transfection rates were relatively high. When the mass ratio of DOTAP/pDNA was 5 ∶1, the particle size of Lip-pOprF-VP22 was(171. 67±1. 27)nm, and the Zeta potential was(11. 30±0. 57)mV. Furthermore, Apt-Lip-pOprF-VP22 can express more OprF protein and significantly promote the maturation of BMDCs. In conclusion, Apt-Lip-pOprF-VP22 can target to DC and promote the maturation of DC.

BACKGROUND:Exercise can elicit generation of coronary col ateral circulation through numerous pro-angiogenic growth factors. It is not enough via a single factor to clearly definite signaling pathways for the generation of col ateral circulation. Many pro-angiogenic growth factors are involved in kal ikrein-kinin system, and there is no report about exercise effects on this system.
OBJECTIVE:To study effects of exercise training on bradykinin expression in rats with myocardial infarction.
METHODS:Thirty Wistar rats were randomly assigned to control group, myocardial infarction group and exercises training group. Rats in the control group were subjected to thoracotomy with no coronary artery ligation. Rats in the other two groups were modeled. In the exercise training group, 3 days after myocardial infarction, rats were subjected to 30-minute exercise training on treadmil , once a day for 4 weeks. At the terminal of the experiment, blood samples were obtained to analyze bradykinin expression by enzyme linked immunosorbent assay, and the myocardium was sampled to analyze relative blood flow by microsphere method.
RESULTS AND CONCLUSION:After exercise training, bradykinin level in the exercise training group was significantly higher than that in the myocardial infarction group (P<0.001). At the end of experiment, the relative blood flows of the exercise training and myocardial infarction groups were both increased compared with before experiment (P<0.05, P<0.001). At the end of experiment, the relative blood flow of the exercise training group was significantly higher than that of the myocardial infarction group (P<0.01). In al the three groups, bradykinin level was significantly correlated with the relative blood flow in the myocardium. These findings indicate exercises training can improve bradykinin expression apparently and increase blood flow in the myocardium, which il ustrates that the kal ikrein-kinin system plays an important role in exercise induced angiogenesis.