ADAMTS-1 expression in rat myocardium after ischemic preconditioning: age-associated differences.

BACKGROUND: It has been found that cardiac protection afforded by ischemic preconditioning (IPC) is significantly reduced in the senescent myocardium. ADAMTS-1 (a disintesrin and metalloprotease with thrombospondin type 1 motifs) has been shown to inhibit angiogenesis in a variety of in vitro and in vivo assays. The aim of this study was to investigate the age-associated differences in ADAMTS-1 protein expression in rat myocardium after ischemic preconditioning. METHODS: Sixty-four young (4 months) and old (24 months) male Sprague-Dawley rats were randomly assigned to an IPC group (40 rats) or a sham group (rats). A model of delayed IPC was induced and rats were sacrificed and myocardial samples were harvested from the ischemic-reperfused region for immunohistochemical detection of ADAMTS-1 at serial time points after IPC. A model of myocardial infarction was produced by ligation of the left anterior descending coronary artery in additional sets of young and old rats after sham or IPC procedures, then age-associated myocardial infarction survival after IPC was calculated. RESULTS: ADAMTS-1 expression increased significantly in old rats compared to young rats (P < 0.05). The mean densities of ADAMTS-1 protein at 0, 6, 12, and 24 hours in young-IPC group after IPC were 0.05 ± 0.01, 0.13 ± 0.03, 0.16 ± 0.04, and 0.12 ± 0.03 vs. 0.07 ± 0.03, 0.20 ± 0.03, 0.24 ± 0.05, and 0.21 ± 0.04 in old-IPC group. IPC resulted in diminished survival rates (5/35 vs. 6/14, old-IPC group vs. old-sham group, P < 0.05), reduced left ventricular fractional shortening ((13.9 ± 2.8)% vs. (18.3 ± 2.3)%, P < 0.05) and increased the myocardial infarction size ((37.9 ± 3.2)% vs. (32.8 ± 5.1)%, P < 0.05) in the older rats. CONCLUSIONS: Cardioprotection with IPC is attenuated in the older heart. ADAMTS-1 expression induced by IPC is greater in old rats. Over-expression of anti-angiogenic factors might be a potential mechanism behind reduced protection after IPC associated with aging.

[Ischemia preconditioning attenuated myocardial ischemia via upregulating the expression of adiponectin in rat].

OBJECTIVE: To investigate whether adiponectin plays a role in the protection of myocardium in the rat myocardial ischemia preconditioning (IPC) model. METHOD: Infarct size was measured by Masson's Trichrome staining, the expression of protein and mRNA of adiponectin at 0, 6, 12 and 24 h after IPC was examined by immunohistochemistry and quantitative real time RT-PCR, plasma levels of adiponectin at above mentioned four time points after IPC were detected by ELISA in IPC and MI rats. RESULT: Infarct size was smaller in IPC than in MI rats (20% ± 2% vs. 31% ± 3%, P < 0.05). The expression of adiponectin mRNA at 6 h and 12 h after IPC was 2.2 and 2.1 times higher than in Sham rats at respective time points (P < 0.05). Immunohistochemistry staining evidenced increased adiponectin expression in the ischemic area and weak expression of adiponectin in non-ischemic area (P < 0.05). Compared to the sham group, the plasma level of adiponectin increased significantly at 0, 6 and 12 h after IPC (0 h: 7.40 ± 0.47 vs. 10.90 ± 1.74; 6 h: 8.18 ± 1.41 vs. 10.98 ± 1.74; 12 h: 6.97 ± 1.02 vs. 9.31 ± 0.96, P < 0.05). CONCLUSION: IPC reduced infarction size, upregulated the myocardial expression of adiponectin at mRNA and protein levels, and increased plasma adiponectin concentration, suggesting that the adiponectin may play a critical role in the protective effect of IPC.

[Effect of ischemia preconditioning on pro- and anti- angiogenic molecule expression and functional arteries formation].

OBJECTIVE: to observe the effect of ischemia preconditioning (IPC) on the expression of pro-angiogenic VEGF, PDGF and anti-angiogenic ADAMTS-1, and arteriogenesis. METHODS: rat heart IPC model was made by 4 circles of occluding the LAD for 6 min followed by 6 min of reperfusion. The expression of VEGF, PDGF-B and ADAMTS-1 in the ischemic area was examined with immunohistochemistry at 6, 12 and 24 h after IPC. IPC plus myocardial infarction model was induced by LAD ligation 24 h after IPC, 14 days later, the anti-SM-α-actin antibody was used to detect the mature neovascularization in the border of the infracted area. RESULTS: VEGF, PDGF-B and ADAMTS-1 were significantly upregulated in the ischemic area in IPC group compared with the control group (P < 0.05). Density of mature arteries was also significantly increased in IPC plus MI group than that in MI group (P < 0.05). CONCLUSION: IPC promoted the formation of mature new arteries which may be modulated by upregulating VEGF, PDGF-B, and ADAMTS-1 expressions.

[Effect of numbers of CD34+CD62L+ cells infused on unrelated umbilical cord blood transplantation in children with acute leukemia].

OBJECTIVE: Several studies have shown that L-selectin on CD34-positive cells play a role in hematopoietic reconstitution after peripheral blood stem cell transplantation and allograft bone marrow transplantation. This study sought to investigate whether the numbers of CD(34)(+)CD(62L)(+) cells infused affect the engraftment of hematopoietic stem cells (HSC) and the time to neutrophil and platelet recovery after unrelated umbilical cord blood transplantation for the treatment of childhood acute leukemia. METHODS: Twenty-three children with acute leukemia who received unrelated umbilical cord blood transplantation of mostly mismatched HLA locus were included in this study. Flow cytometry was used to count the numbers of CD(34)(+)CD(62L)(+) cells after freezing-thawing by labelling the cells with anti-CD(34) and anti-CD62L. The patients' clinical data including body weight, engraftment of the HSC, times to neutrophil and platelet recovery were evaluated. RESULTS: Twenty-one patients who received CD(34)(+)CD(62L)(+) cell infusion at a number ranging from 1.37 x 10(5)/kg to 2.68 x 10(6)/kg (median, 3.567 x 10(5)/kg) had successful engraftment of the unrelated umbilical HSC. The numbers of CD(34)(+)CD(62L)(+) cells infused were statistically different between patients who had successful engraftment of the umbilical HSC and those who had not (P < 0.05). The engraftment occurred more commonly in patients who received > 1.3 x 10(5) CD(34)(+)CD(62L)(+) cells/kg. The time of neutrophil recovery (> 500/ microl) ranged from 11 days to 32 days (median, 17.5 days). The data of the time to platelet recovery (> 2 x 10(5)/ microl) were obtained in 18 patients, and it ranged from 12 days to 118 days (median, 14 days). There seemed to be a tendency of correlation between the numbers of CD(34)(+)CD(62L)(+) cells infused and time to platelet recovery (gamma = -0.324, 0.05 < P < 0.1), whereas the numbers of CD(34)(+)CD(62L)(+) cells infused correlated with the time to platelet recovery (gamma = -0.470, P < 0.05). CONCLUSION: This study suggests that the numbers of CD(34)(+)CD(62L)(+) cells infused might be involved in the engraftment of HSC and hematologic reconstitution after umbilical cord blood transplantation.