Heart failure is one kind of cardiovascular disease with high risk and high incidence. As an effective treatment of heart failure, artificial heart is gradually used in clinical treatment. Blood compatibility is an important parameter or index of artificial heart, and how to evaluate it through hemodynamic design and in vitro hemolysis test is a research hotspot in the industry. This paper first reviews the research progress in hemodynamic optimization and in vitro hemolysis evaluation of artificial heart, and then introduces the research achievements and progress of the team in related fields. The hemodynamic performance of the blood pump optimized in this paper can meet the needs of use. The normalized index of hemolysis obtained by in standard vitro hemolysis test is less than 0.1 g/100 L, which has good hemolysis performance in vitro. The optimization method described in this paper is suitable for most of the development of blood pump and can provide reference for related research work.
Spectrophotometry is a simple hemolytic evaluation method commonly used in new drugs, biomedical materials and blood products. It is for the quantitative analysis of the characteristic absorption peaks of hemoglobin. Therefore, it is essential to select the correct detection wavelength when the evaluation system has influences on the conformation of hemoglobin. Based on the study of changes in the characteristic peaks over time of the hemolysis supernatant in four systems, namely, cell culture medium, phosphate buffered saline (PBS), physiological saline and banked blood preservation solution, using continuous wavelength scanning, the selections of detection wavelength were proposed as follows. In the cell culture medium system, the wavelength of 415 nm should be selected within 4 h; , near 408 nm should be selected within 4~72 h. In PBS system, within 4 h, 541 nm, 577 nm or 415 nm should be selected; 4~72 h, 541 nm, 577 nm or near 406 nm should be selected. In physiological saline system, within 4 h, 414 nm should be selected; 4~72 h, near 405 nm should be selected; within 12 h, 541 nm or 577 nm could also be selected. In banked blood preservation solution system, within 72 h, 415 nm, 540 nm or 576 nm should be selected.
ObjectiveTo investigate the effect of inhibiting autotaxin (ATX)-lysophosphatidic acid (LPA) pathway on the cartilage of knee osteoarthritis in rats.MethodsPrimary chondrocytes within three generations of Sprague-Dawley rats (8 weeks old, male) were randomly divided into 6 groups, including blank control group, model group, 1 μmol/L PF-8380 group, 10 μmol/L PF-8380 group, 1 μmol/L Ki16425 group, and 10 μmol/L Ki16425 group. Except for the blank control group, the other groups were modeled with osteoarthritis using interleukin-1β (10 ng/mL, 24 h), and then the experimental groups, i.e., 1 μmol/L PF-8380 group, 10 μmol/L PF-8380 group, 1 μmol/L Ki16425 group, and 10 μmol/L Ki16425 group, were intervened with 1, 10 μmol/L PF-8380 (ATX inhibitor) and 1, 10 μmol/L Ki16425 (LPA receptor antagonist) for 24 h, respectively. immunocytochemistry staining was used to determine the expression of type Ⅱ collagen (Col Ⅱ) in cytoplasm, and Western Blot was used to determine the expression of ATX, LPA, and matrix metalloproteinase-13 (MMP-13) in chondrocytes.ResultsCompared with the blank control group, the average absorbance of Col Ⅱ in chondrocytes in the model group was significantly reduced (0.003 9±0.000 8 vs. 0.110 0± 0.009 0, P<0.05). The expression levels of ATX, LPA, and MMP-13 in chondrocytes in the model group, 1 μmol/L PF-8380 group, 10 μmol/L PF-8380 group, and 1 μmol/L Ki16425 group were significantly higher than those in the blank control group, while the expression levels of ATX, LPA, and MMP-13 in the 10 μmol/L Ki16425 group had no significant difference with those in the blank control group; the expression levels of ATX, LPA, and MMP-13 in the model group, 10 μmol/L PF-8380 group, and 1 μmol/L PF-8380 group decreased in order; the expression levels of ATX, LPA, and MMP-13 in the model group, 1 μmol/L Ki16425 group, and 10 μmol/L Ki16425 group decreased in order.ConclusionInhibiting ATX-LPA pathway may inhibit the up-regulation of MMP-13 levels in articular cartilage of osteoarthritis in rats to reduce the damage of cartilage.
Abstract： Objective To summarize the clinical experiences of performing extracorporeal membrane oxygenation (ECMO) on patients with heart and respiratory failure, and compare the clinical outcomes of Medtronic system and Quadrox PLS system. Methods We retrospectively analyzed the clinical data of 121 heart and respiratory failure patients who underwent ECMO treatment in Fu Wai Hospital from December 2004 to December 2009. Based on the different systems used, 121 patients were divided into two groups. In group M, there were 65 patients including 41 males and 24 females, with an age of 26.6±25.9 years; and they accepted Medtronic ECMO system treatment. In group Q, there were 56 patients including 39 males and 17 females, with an age of 32.4±23.9 years and they underwent Quadrox PLS ECMO system treatment. The evaluation of the clinical outcomes of these two different systems was based on the comparison of transmembrane pressure drop (TMPD), anticoagulation, hemolysis, plasma leakage, organ function, complication and hospital mortality between the two groups. Results Compared with group M, ECMO with Quadrox PLS system was associated with lower TMPD (at the beginning of ECMO: 15.0±6.0 mm Hg vs.28.0±5.0 mm Hg, P=0.000; 24 hours later: 16.0±5.0 mm Hg vs. 30.0±7.0 mm Hg, P=0.000) and less thrombus formation(7.1% vs.23.1%, P=0.037), less plasma leakage (0.0% vs. 50.8%, P=0.000), less hemolysis (14.3% vs. 29.2%, P=0.047). There were no significant differences between the two groups in support duration, complication rate, and hospital mortality(Pgt;0.05). Conclusion Both devices have similar effects for safe clinical application, but Quadrox PLS ECMO system has a relatively high biocompatibility with lower TMPD, less plasma leakage, and thrombus formation.
An implantable axial blood pump was designed according to the circulation assist requirement of severe heart failure patients of China. The design point was chosen at 3 L/min flow rate with 100 mm Hg pressure rise when the blood pump can provide flow rates of 2-7 L/min. The blood pump with good hemolytic and anti-thrombogenic property at widely operating range was designed by developing a structure that including the spindly rotor impeller structure and the diffuser with splitter blades and cantilevered main blades. Numerical simulation and particle image velocimetry (PIV) experiment were conducted to analyze the hydraulic, flow fields and hemolytic performance of the blood pump. The results showed that the blood pump could provide flow rates of 2-7 L/min with pressure rise of 60.0-151.3 mm Hg when the blood pump rotating from 7 000 to 11 000 r/min. After adding the splitter blades, the separation flow at the suction surface of the diffuser has been reduced efficiently. The cantilever structure changed the blade gap from shroud to hub that reduced the tangential velocity from 6.2 m/s to 4.3-1.1 m/s in blade gap. Moreover, the maximum scalar shear stress of the blood pump was 897.3 Pa, and the averaged scalar shear stress was 37.7 Pa. The hemolysis index of the blood pump was 0.168% calculated with Heuser’s hemolysis model. The PIV and simulated results showed the overall agreement of flow field distribution in diffuser region. The blood damage caused by higher shear stress would be reduced by adopting the spindle rotor impeller and diffuser with splitter blades and cantilevered main blades. The blood could flow smoothly through the axial blood pump with satisfactory hydraulics performance and without separation flow.
The objective of the study is to analyze the biological characteristics and stability of the linear derivative Bac2a from bactenecin, compared with the control peptide melittin. The secondary structure, antibacterial activity, hemolytic activity, cell toxicity and stability of the Bac2a were determined by circular dichroism spectroscopy, broth micro-dilution method and MTT assay. The results showed that Bac2a was a nonregular curl in aqueous solution, however, it was an α-helix structure in the hydrophobic environment. The minimal inhibitory concentration (MIC) of Bac2a ranged from 2 to 32 μmol/L, so the bacteriostatic activity of Bac2a was strong. The hemolytic rate was only 14.81% when the concentration of Bac2a was 64 μmol/L, which showed that the hemolytic rate of Bac2a was low. The therapy index of Bac2a was 3.26, and the cytotoxicity was relatively low, thus the cell selectivity was relatively high. In addition, with the heating treatment of 100℃ for 1 h, Bac2a still possessed rather a high antibacterial activity and showed a good heating stability. In a word, Bac2a has good application prospects in food, medicine and other fields, and is expected as a substitute for traditional antibiotics.