[Effect of ischemic postconditioning on activation of p38 mitogen activated protein kinase and cardiac myocyte apoptosis in rats].

OBJECTIVE: To explore the change of phospho-p38 (P-p38) mitogen activated protein kinase(MAPK) and its influence on myocardial apoptosis in reperfusion injury in postconditioning. METHODS: Totally 60 rats were equally and randomly divided into six groups: Sham group,reperfusion injury (R/I) group, postconditioning (Post) group, SB203580 (I_p38) group, anisomycin plus postconditioning (Ani+post) group,and anisomycin (Ani) group. After the model of acute myocardial infarction was established,placebo solution (DMSO), SB203580 (1 mg/kg), or anisomycin (2 mg/kg) was injected through jugular vein 5 minutes before reperfusion. Six hours later, 3 rats in each group were executed and the hearts were separated to measure the signaling molecules including phospho-p38,tumor necrosis factor-alpha (TNF-α), Caspase-8, Bcl-2/Bax, and cytochrome-c (Cyt-c). Twenty-four hours later,the hemodynamic data were measured in the remaining rats,and then blood was collected to determine the serum markers of cardiac damage. After that,hearts were separated to measure the infarction area and apoptosis. RESULTS: Six hours after reperfusion,the expressions of P-p38 in Post and I_p38 group were significantly lower than those in R/I group (P<0.05), significantly higher in Ani+post and Ani group than in Post group (P<0.05), and significantly lower in Ani+post group than in R/I group (P<0.05). The expressions of TNF-α and Caspase-8 were significantly lower in Post and I_p38 group than in R/I group (P<<.05) and significantly higher in Ani+post and Ani group than in Post group (P<0.05). The expression of TNF-α was significantly lower in Ani+post group than in R/I group (P<0.05). The expression of Bcl-2 was significantly higher in Post and I_p38 groups than in R/I group (P<0.05) and significantly lower in Ani+post and Ani groups than in Post group (P<0.05). The expression of Bax was significantly lower in Post and I_p38 groups than in R/I group (P<0.05) and were significantly higher in Ani+post and Ani group than in Post group (P<0.05). The expression of Cyt-c after the removal of the cytoplasm mitochondria was significantly lower in Post and I_p38 group than in R/I group (P<0.05) and was significantly higher in Ani+post and Ani group than in Post group (P<0.05). Twenty-four hours after reperfusion,the values of rate-pressure product and ± delta pressure/delta time max were significantly lower in R/I group than in Post and I_p38 groups (P<0.05) and was significantly higher in Post group than in Ani+post and Ani group (P<0.05). The apoptotic index (AI) was significantly lower in Post and I_p38 groups than in R/I group (P<0.05) and was significantly higher in Ani+post and Ani groups than in Post group (P<0.05). The values of creatine kinase and creatine kinase-MB were significantly lower in Post,Ani+post, and I_p38 groups than in R/I group (P<0.05) and were significantly higher in Ani+post and Ani group than in Post group (P<0.05). The area of necrosis/area at risk ratio was significantly lower in Post and I_p38 groups than in R/I group (P<0.05) and was significantly higher in Ani+post and Ani groups than in Post group (P<0.05). CONCLUSION: Postconditioning can inhibit the phosphorylation of p38 MAPK,through which it can attenuate cardiac myocyte apoptosis by both extrinsic and mitochondria pathways.

Aggressive plaque modification with rotational atherectomy and cutting balloon for optimal stent expansion in calcified lesions.

OBJECTIVE: To evaluate the factors affecting optimal stent expansion in calcified lesions treated by aggressive plaque modification with rotational atherectomy (RA) and a cutting balloon (CB). METHODS: From January 2014 to May 2015, 92 patients with moderate to severe coronary calcified lesions underwent rotational atherectomy and intravascular ultrasound imaging at Chinese PLA General Hospital (Beijing, China) were included in this study. They were divided into a rotational artherectomy combined with cutting balloon (RACB) group (46 patients treated with RA followed by CB angioplasty) and an RA group (46 patients treated with RA followed by plain balloon angioplasty). Another 40 patients with similar severity of their calcified lesions treated with plain old balloon angioplasty (POBA) were demographically matched to the other groups and defined as the POBA group. All patients received a drug-eluting stent after plaque preparation. Lumen diameter and lumen diameter stenosis (LDS) were measured by quantitative coronary angiography at baseline, after RA, after dilatation, and after stenting. Optimal stent expansion was defined as the final LDS < 10%. RESULTS: The initial and post-RA LDS values were similar among the three groups. However, after dilatation, the LDS significantly decreased in the RACB group (from 54.5% ± 8.9% to 36.1% ± 7.1%) but only moderately decreased (from 55.7% ± 7.8% to 46.9% ± 9.4%) in the RA group (time × group, P < 0.001). After stenting, there was a higher rate of optimal stent expansion in the RACB group (71.7% in the RACB group, 54.5% in the RA group, and 15% in the POBA group, P < 0.001), and the final LDS was significantly diminished in the RACB group compared to the other two groups (6.0% ± 2.3%, 10.8% ± 3.3%, 12.7% ± 2.1%, P < 0.001). Moreover, an LDS ≤ 40% after plaque preparation (OR = 2.994, 95% CI: 1.297-6.911) was associated with optimal stent expansion, which also had a positive correlation with the appearance of a calcified ring split (r = 0.581, P < 0.001). CONCLUSIONS: Aggressive plaque modification with RA and CB achieve more optimal stent expansion. An LDS ≤ 40% after plaque modification was a predictive factor for optimal stent expansion in calcified lesions. This parameter was also associated with the presence of calcified ring split.

Post-conditioning with gradually increased reperfusion provides better cardioprotection in rats.

BACKGROUND: Rapid and complete reperfusion has been widely adopted in the treatment of patients with acute myocardial infarction (AMI), but this process sometimes can cause severe reperfusion injury. This study aimed to investigate different patterns of post-conditioning in acute myocardial ischemia-reperfusion injury, and to detect the role of mitogen activated protein kinase (MAPK) during the injury. METHODS: RATS WERE RANDOMLY DIVIDED INTO FIVE GROUPS: sham group, reperfusion injury (R/ I) group, gradually decreased reperfusion group (GDR group, 30/10-25/15-15/25-10/30 seconds of reperfusion/ischemia), equal reperfusion group (ER group, 20/20 seconds reperfusion/ischemia, 4 cycles), and gradually increased reperfusion group (GIR group, 10/30-15/25-25/15-30/10 seconds of reperfusion/ischemia). Acute myocardial infarction and ischemic post-conditioning models were established in the rats. Six hours after reperfusion, 3 rats from each group were sacrificed and myocardial tissues were taken to measure the expressions of phosphorylation of extracellular signal-regulated protein kinase (P-ERK), phosphorylated c-Jun N-terminal kinase (P-JNK), mitogen-activated protein kinase p38 (p38 MAPK), tumor necrosis factor-α (TNF-α), caspases-8 in the myocardial tissue, and cytochrome c in the cytosol using Western blot. Hemodynamics was measured at 24 hours after reperfusion, the blood was drawn for the determination of cardiac enzymes, and the heart tissue was collected for the measurement of apoptosis using TUNEL. One-way analysis of variance and the Q test were employed to determine differences in individual variables between the 5 groups. RESULTS: Three post-conditioning patterns were found to provide cardioprotection (P<0.05) compared with R/I without postconditioning. GIR provided the best cardioprotection effect, followed by ER and then GDR. Apoptotic index and serum marker levels were reduced more significantly in GIR than in ER (P<0.05). The enhanced cardioprotection provided by GIR was accompanied with significantly increased levels of P-ERK 1/2 (1.82±0.22 vs. 1.54±0.32, P<0.05), and lower levels of p-JNK, p38 MAPK, TNF-α, caspase-8, caspase-9 and cytochrome in the cytoplasm (P<0.05), compared with ER. The infarct size was smaller in the GIR group than in the ER group, but this difference was not significant (16.30%±5.22% vs. 20.57%±6.32%, P<0.05). All the measured variables were improved more significantly in the GIR group than in the GDR group (P<0.05). CONCLUSION: Gradually increased reperfusion in post-conditioning could attenuate reperfusion injury more significantly than routine method, thereby the MAPK pathway plays an important role in this process.

Cutting-balloon angioplasty before drug-eluting stent implantation for the treatment of severely calcified coronary lesions.

BACKGROUND: Severely calcified coronary lesions respond poorly to balloon angioplasty, resulting in incomplete and asymmetrical stent expansion. Therefore, adequate plaque modification prior to drug-eluting stent (DES) implantation is the key for calcified lesion treatment. This study was to evaluate the safety and efficacy of cutting balloon angioplasty for severely calcified coronary lesions. METHODS: Ninety-two consecutive patients with severely calcified lesions (defined as calcium arc ≥ 180° calcium length ratio ≥ 0.5) treated with balloon dilatation before DES implantation were randomly divided into two groups based on the balloon type: 45 patients in the conventional balloon angioplasty (BA) group and 47 patients in the cutting balloon angioplasty (CB) group. Seven cases in BA group did not satisfactorily achieve dilatation and were transferred into the CB group. Intravascular ultrasound (IVUS) was performed before balloon dilatation and after stent implantation to obtain qualitative and quantitative lesion characteristics and evaluate the stent, including minimum lumen cross-sectional area (CSA), calcified arc and length, minimum stent CSA, stent apposition, stent symmetry, stent expansion, vessel dissection, and branch vessel jail. In-hospital, 1-month, and 6-month major adverse cardiac events (MACE) were reported. RESULTS: There were no statistical differences in clinical characteristics between the two groups, including calcium arc (222.2° ± 22.2° vs. 235.0° ± 22.1°, P = 0.570), calcium length ratio (0.67 ± 0.06 vs. 0.77 ± 0.05, P = 0.130), and minimum lumen CSA before PCI (2.59 ± 0.08 mm(2) vs. 2.52 ± 0.08 mm(2), P = 0.550). After stent implantation, the final minimum stent CSA (6.26 ± 0.40 mm(2) vs. 5.03 ± 0.33 mm(2); P = 0.031) and acute lumen gain (3.74 ± 0.38 mm(2) vs. 2.44 ± 0.29 mm(2), P = 0.015) were significantly larger in the CB group than that of the BA group. There were not statistically differences in stent expansion, stent symmetry, incomplete stent apposition, vessel dissection and branch vessel jail between two groups. The 30-day and 6-month MACE rates were also not different. CONCLUSIONS: Cutting balloon angioplasty before DES implantation in severely calcified lesions appears to be more efficacies including significantly larger final stent CSA and larger acute lumen gain, without increasing complications during operations and the MACE rate in 6-month.

Comparison of human amniotic fluid-derived and umbilical cord Wharton's Jelly-derived mesenchymal stromal cells: Characterization and myocardial differentiation capacity.

OBJECTIVE: To compare the characterization and myocardial differentiation capacity of amniotic fluid-derived mesenchymal stromal cells (AF MSCs) and umbilical cord Wharton's Jelly-derived mesenchymal stromal cells (WJ MSCs). METHODS: The human AF MSCs were cultured from amniotic fluid samples obtained by amniocentesis. The umbilical cord WJ MSCs were obtained from Wharton's Jelly of umbilical cords of infants delivered full-term by normal labor. The morphology, growth curves, and analyses by flow cytometry of cell surface markers were compared between the two types of cells. Myocardial genes (GATA-4, c-TnT, α-actin, and Cx43) were detected by real-time PCR and the corresponding protein expressions were detected by Western blot analysis after myocardial induced in AF MSCs and WJ MSCs. RESULTS: Our findings revealed AF MSCs and WJ MSCs shared similar morphological characteristics of the fibroblastoid shape. The AF MSCs were easily obtained than the WJ MSCs and had a shorter time to reach adherence of 2.7 ± 1.6 days to WJ MSCs of 6.5 ± 1.8 days. The growth curves by MTT cytotoxic assay showed the AF MSCs had a similar proliferative capacity at passage 5 and passage 10. However, the proliferative capacities of WJ MSCs were decreased at 5 passage relative to 10 passage. Both AF stem cells and WJ stem cells had the characteristics of mesenchymal stromal cells with some characteristics of embryonic stem cells. They express CD29 and CD105, but not CD34. They were positive for Class I major histocompatibility (MHC I) antigens (HLA-ABC), and were negative, or mildly positive, for MHC Class II (HLA-DR) antigen. Oct-4 was positive in all the two cells types. Both AF MSCs and WJ MSCs could differentiate along myocardium. The differentiation capacities were detected by the expression of GATA-4, c-TnT, α-actin, Cx43 after myocardial induction. CONCLUSIONS: Both AF MSCs and WJ MSCs have the potential clinical application for myogenesis in cardiac regenerative therapy.