Protective effects of myocardium-targeted nanoparticles loaded L-arginineon on sepsis-induced myocardial injury / 中华危重病急救医学

Objective:To prepare primary cardiomyocyte (PCM) specific peptide-conjugated mesoporous silicon nanoparticles (MSN) with L-arginine (LA) as a core (PCM-MSN@LA), and evaluate its specific protective effect on septic myocardium.Methods:PCM-MSN@LA was prepared by condensation reaction, the characterization of PCM-MSN@LA, the amount of LA modification and release was detected, and the phagocytosis of PCM-MSN@LA and its affinity to myocardial tissue was observed. ① Experiment one: SD neonatal rat cardiomyocytes were divided into control group (Con group), lipopolysaccharide (LPS) group, MSN@LA/LPS group and PCM-MSN@LA/LPS group. The LPS group was stimulated with 5 mg/L LPS for 16 hours, while the MSN@LA/LPS group and PCM-MSN@LA/LPS group were treated with 5 mg/L LPS and 25 mg/L LA-containing nanoparticles (MSN@LA and PCM-MSN@LA) for 16 hours. Cell viability and reactive oxygen species (ROS) production levels were detected. Apoptosis was observed via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method (TUNEL). Western Blot was used to detect the changes in endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) proteins. ② Experiment two: 64 healthy male C57BL/6 mice were divided into Sham group, LPS group, MSN@LA/LPS group and PCM-MSN@LA/LPS group by random number table method, 16 mice in each group. LPS group were injected 50 mg/kg LPS intraperitoneally. MSN@LA/LPS group and PCM-MSN@LA/LPS group were injected with 0.5 mg/kg MSN@LA and PCM-MSN@LA via tail vein immediately after intraperitoneal injection of LPS. Eight animals in each group were used to observe the 24-hour survival rate, and the other 8 mice were used to detect cardiac function by echocardiography at 12 hours after operation; mRNA expressions of interleukin (IL-1, IL-6) and tumor necrosis factor-α (TNF-α) were measured by real-time fluorescent quantitative polymerase chain reaction (RT-qPCR).Results:PCM-MSN@LA was spherical, with particle size of about 180 nm, Zeta potential of about -21 mV, with LA loaded. The amount of LA modification and release rate were 12.3% and 24.3%, respectively. Cell phagocytosis experiments showed that PCM-MSN@LA had the targeting ability of cardiomyocytes and myocardial tissue. Experiment one: after LPS stimulation of myocardial cells, cell viability decreased, while ROS generation, apoptosis, eNOS and iNOS protein expressions increased. Compared with LPS group, MSN@LA/LPS group and PCM-MSN@LA/LPS group had higher cell viability, reduced ROS levels and apoptosis, increased expressions of eNOS and iNOS. PCM-MSN@LA/LPS group changed the above effect further than MSN@LA/LPS group [cell viability ( A value): 0.51±0.08 vs. 0.41±0.03, ROS (relative fluorescence intensity): 28 450±1 941 vs. 35 628±2 551, TUNEL positive cells/total cells: 0.27±0.03 vs. 0.35±0.04, eNOS/β-Tubulin: 1.467±0.046 vs. 1.201±0.131, iNOS/β-Tubulin: 1.700±0.033 vs. 1.577±0.068, all P < 0.05]. Experiment two: the number of 24-hour survive in MSN@LA/LPS group and PCM-MSN@ LA/LPS group were higher than LPS group (number: 2, 4 vs. 1, P values were 0.36 and 0.03 respectively). Compared with Sham group, the cardiac function of LPS group was significantly inhibited and the mRNA expression of inflammatory factors increased. The PCM-MSN@LA/LPS group had higher left ventricular ejection fraction (LVEF) and left ventricular short-axis shortening rate (LVFS) than LPS group, and lower mRNA expressions of IL-1, IL-6, and TNF-α mRNA [LVEF: 0.456±0.019 vs. 0.337±0.017, LVFS: (21.97±1.78)% vs. (15.53±1.67)%, IL-1 mRNA (2 -ΔΔCT): 169.22±8.95 vs. 189.79±6.79, IL-6 mRNA (2 -ΔΔCT): 19.90±1.60 vs. 23.74±1.45, TNF-α mRNA (2 -ΔΔCT): 8.21±0.81 vs. 11.00±1.48, all P < 0.05]. There was no significant difference in each index between the MSN@LA/LPS group and LPS group. Conclusion:PCM-MSN@LA with myocardial targeting characteristic significantly increased the activity of myocardial cells, down-regulated the expression of inflammatory factors and the production of ROS, alleviated cardiac insufficiency in sepsis, and achieved the targeted treatment of myocardial injury in sepsis.

Maternal hepatic venous hemodynamics and cardiac output in normal and fetal growth restricted pregnancies / 中南大学学报(医学版)

To evaluate relationship of maternal hepatic vein Doppler flow parameters and cardiac output (CO) with neonatal birth weight in uncomplicated pregnancies (UP) and pregnancies complicated by fetal growth restriction (FGR) .
 Methods: Hepatic vein impedance index (HVI), venous pulse transit time (VPTT), and CO were measured in women with UP at the 14th-37th weeks and complicated by FGR at the 26th-37th weeks who underwent maternal hepatic hemodynamic and echocardiographic examination during the ultrasonography. After delivery, the birth weight and the birth weight percentile of each neonate in this study were recorded. Correlations among HVI, VPTT, and CO were analyzed.
 Results: In the UP group, HVI, VPTT, and CO changed with the increase of gestation. In the FGR group, HVI was higher, VPTT was shorter, CO and neonatal birth weight were obviously lower than those in the UP at the 26th-37th weeks (P<0.05).
 Conclusion: There is a series of adaptive changes in hepatic venous hemodynamics and CO in UP with the increase of gestation to meet the demand of fetal growth, while the maladaptive changes in hepatic venous hemodynamics and CO in pregnant woman may contribute to FGR.

Roles of MyD88 and TRIF in cardiac dysfunction during sepsis / 中华危重病急救医学

Objective To investigate the roles of myeloid differentiation factor 88 (MyD88) and TIR domain-containing adaptor inducing interferon-β (TRIF) in sepsis-induced myocardial dysfunction, and to analyze whether strain rate (SR) can be early sensitive evaluation for septic heart failure.Methods Sixty-four healthy male C57BL/6 mice were divided into four groups by random number table (n = 16 in each group): sham group, cecum ligation and puncture (CLP)-induced sepsis model group, anti-MyD88 group and anti-TRIF group. The anti-MyD88 group and anti-TRIF group were injected with 5μL/g of anti-MyD88 antibody or anti-TRIF antibody through the tail veins 2 hours before CLP. Eight animals in each group were used to observe the survival of 24 hours, and the other 8 myocardial tissues were harvested for examination. The cardiac function was evaluated by echocardiography before and 6 hours and 12 hours after operation. The mRNA expressions of MyD88, TRIF and inflammatory factors in myocardium were measured by polymerase chain reaction (PCR) at 24 hours after operation, and the degree of neutrophils infiltration was detected by myeloperoxidase (MPO) activity.Results The number of 24-hour survive in anti-MyD88 group and anti-TRIF group were higher than that in CLP group (number: 4, 3 vs. 2,P = 0.044,P = 0.047). Compared with sham group, the cardiac function was significantly decreased, the mRNA expressions of myocardial tissues MyD88, TRIF, interleukin (IL-1, IL-6) and tumor necrosis factor-α (TNF-α) were significantly increased, and the infiltration of neutrophils were obvious in CLP group. Compared with CLP group, the left ventricular short axis fractional shortening rate (FS) and SR were significantly increased after 12 hours in anti-MyD88 group and anti-TRIF group [FS: (49.52±1.78)%, (49.89±1.49)%vs. (41.11±1.63)%, SR (s-1): 17.63±2.16, 17.85±1.64 vs. 12.55±1.84]; the mRNA expressions of MyD88, TRIF and inflammatory factors were significantly decreased [MyD88 mRNA (A value): 0.463±0.046, 0.505±0.048 vs. 0.638±0.102, TRIF mRNA (A value): 0.413±0.031, 0.410±0.021 vs. 0.625±0.057, IL-1 mRNA (A value):0.569±0.101, 0.570±0.091 vs. 0.946±0.171, IL-6 mRNA (A value): 0.551±0.143, 0.431±0.157 vs. 0.850±0.194, TNF-α mRNA (A value): 0.471±0.082, 0.444±0.093 vs. 0.707±0.094]; and the infiltration of neutrophils were significantly decreased [MPO (U/L): 62.34±2.60, 60.87±2.40 vs. 73.83±4.90], with statistically significant differences (allP 0.05).Conclusions Blocking MyD88 and TRIF expression play significant and similar roles in protecting cardiac deterioration from sepsis by attenuating cytokine release, reducing neutrophil infiltration. SR can sensitively assess septic cardiac dysfunction.