Background:Inflammatory responses, especially by CD4+T cells activated by dendritic cells, are known to be important in the pathophysiology of cardiac repair after myocardial infarction (MI). ...Although co-stimulatory signals through B7 (CD80/86) and CD28 are necessary for CD4+T cell activation and survival, the roles of these signals in cardiac repair after MI are still unclear.Methods and Results:C57BL/6 (Control) mice and CD28 knockout (CD28KO) mice were subjected to left coronary artery permanent ligation. The ratio of death by cardiac rupture within 5 days after MI was significantly higher in CD28KO mice compared with Control mice. Although there were no significant differences in the infarct size between the 2 groups, left ventricular end-diastolic and end-systolic diameters were significantly increased, and fractional shortening was significantly decreased in CD28KO mice compared with Control mice. Electron microscopic observation revealed that the extent of extracellular collagen fiber was significantly decreased in CD28KO mice compared with Control mice. The number of α-smooth muscle actin-positive myofibroblasts was significantly decreased, and matrix metalloproteinase-9 activity and the mRNA expression of interleukin-1β were significantly increased in CD28KO mice compared with Control mice.Conclusions:Deletion of CD28 co-stimulatory signals exacerbates left ventricular remodeling and increases cardiac rupture after MI through prolongation of the inflammatory period and reduction of collagen fiber in the infarct scars. (Circ J 2016; 80: 1971–1979)
Dipeptidyl peptidase-4 (DPP-4) inhibitors are hypoglycemic agents. DPP-4 inhibitor has cardioprotective effects after transverse aortic constriction (TAC), but role of DPP-4 on cardiac fibrosis after ...TAC is not well known. Our aim was to determine the effects of DPP-4 on cardiac fibrosis in murine TAC model. Wild-type mice and DPP-4 knockout mice were subjected to TAC. Wild-type mice were then treated with vehicle or DPP-4 inhibitor. DPP-4 activities in serum and heart tissue were significantly increased at 2 weeks after TAC, but they were significantly decreased by DPP-4 inhibitor treatment. The inhibition of DPP-4 did not affect left ventricular hypertrophy, but improved cardiac function and decreased myocardial and perivascular fibrosis after TAC. The inhibition of DPP-4 decreased the collagen type III/I ratio in myocardium. These results suggest that DPP-4 inhibition ameliorates the progression of heart failure after TAC by changing the quality and quantity of cardiac fibrosis.
Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of oral hypoglycemic agents for patients with type 2 diabetes mellitus and have potential antiatherosclerotic properties. Meanwhile, it is ...unclear how DPP-4 inhibitors have protective effects on atherosclerosis. Our aim was to determine the effects and its mechanisms of DPP-4 inhibitors on cultured endothelial cells. Human umbilical vein endothelial cells (HUVECs) were cultured in hypoxic condition. To evaluate the protective effects of DPP-4 inhibitor on HUVECs, DPP-4 inhibitor was added in the cell culture medium and the cell viability was assessed by TUNEL assay. And we examined the intracellular signaling pathways in relation to the effects of DPP-4 inhibitor. DPP-4 inhibition had beneficial effects by inhibiting the apoptosis under hypoxic conditions in HUVECs. The antiapoptotic effects of DPP-4 inhibitor were abolished by the pretreatment with a CXCR4 antagonist or a Stat3 inhibitor. DPP-4 inhibition has beneficial effects on HUVECs by inhibiting the apoptosis under hypoxic conditions. SDF-1α/CXCR4/Stat3 pathways might be involved in the mechanisms of the cytoprotective effects of DPP-4 inhibitor. These results suggested that DPP-4 inhibitor has a potential for protecting vessels.
Abstract Aims Dipeptidyl peptidase-4 (DPP-4) inhibitors are reported to have protective effects on various cells but it is unclear how DPP-4 inhibitors have cardioprotective effects. Our aim was to ...study the mechanisms of cardioprotective effects by DPP-4 inhibition. Methods and results C57BL/6 mice and DPP-4 knockout (DPP-4KO) mice were subjected to left coronary artery ligation to produce acute myocardial infarction (MI). C57BL/6 mice were then treated with vehicle or DPP-4 inhibitor. Left ventricular function, infarct size, the number of vessels, and myocardial ischemia were assessed at 5 days after MI. The treatment with DPP-4 inhibitor significantly improved cardiac function and decreased the infarct size. DPP-4 inhibitor increased the ratio of endothelial cell numbers to a cardiomyocyte. The extent of myocardial ischemia and the number of TUNEL-positive cells in the border area were significantly decreased by DPP-4 inhibitor. Stromal cell-derived factor-1α (SDF-1α) level in myocardium was significantly increased by DPP-4 inhibitor. Those cardioprotective effects after MI were also recognized in DPP-4KO mice. DPP-4 protein was expressed on rat neonatal cardiomyocytes and DPP-4 inhibitor significantly reduced hypoxia-induced apoptosis in the cardiomyocytes. However, this effect was abolished by the pretreatment with a CXCR4 antagonist or a signal transducer and activator of transcription 3 (STAT3) inhibitor. The beneficial effects of DPP-4 inhibitor on heart failure after MI were abolished by cardiomyocyte-specific deletion of STAT3. Conclusions DPP-4 inhibition may have direct protective effects on the post-MI heart by inducing an antiapoptotic effect and inhibiting a decrease in vessel number through the SDF-1α/CXCR4-mediated STAT3 signaling pathway.
Dipeptidyl peptidase-4 (DPP-4) inhibitors are relatively new class of anti-diabetic drugs. Some protective effects of DPP-4 on cardiovascular disease have been described independently from ...glucose-lowering effect. However, the detailed mechanisms by which DPP-4 inhibitors exert on endothelial cells remain elusive. The purpose of this research was to determine the effects of DPP-4 inhibitor on endothelial barrier function. Human umbilical vein endothelial cells (HUVECs) were cultured and exposed to hypoxia in the presence or absence of Diprotin A, a DPP-4 inhibitor. Immunocytochemistry of vascular endothelial (VE-) cadherin showed that jagged VE-cadherin staining pattern induced by hypoxia was restored by treatment with Diprotin A. The increased level of cleaved β-catenin in response to hypoxia was significantly attenuated by Diprotin A, suggesting that DPP-4 inhibition protects endothelial adherens junctions from hypoxia. Subsequently, we found that Diprotin A inhibited hypoxia-induced translocation of NF-κB from cytoplasm to nucleus through decreasing TNF-α expression level. Furthermore, the tube formation assay showed that Diprotin A significantly restored hypoxia-induced decrease in number of tubes by HUVECs. These results suggest that DPP-4 inhibitior protects HUVECs from hypoxia-induced barrier impairment.
Background: 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins), which are widely used to lower plasma cholesterol levels, have been reported to have various pleiotropic effects such ...as protective effect of endothelial cells, angiogenic effect, antioxidant effect and anti-inflammatory effect. It is unclear, however, whether statins have any effects on the progression from left ventricular (LV) hypertrophy to heart failure in the established hypertrophied heart. Methods and Results: C57BL/6 mice were treated with pitavastatin (pitava) or vehicle (control) from 2 weeks (established hypertrophy stage) after transverse aortic constriction (TAC) and the treatment was continued for 4 weeks. Pitavastatin significantly inhibited the progression from LV hypertrophy to heart failure as assessed on echocardiography. The cardiomyocyte cross-sectional area was significantly increased in the control group compared to the sham-operated mice (sham group), but it was not significantly different between the control group and the pitava group at 6 weeks after TAC. Moreover, pitavastatin induced myocardial angiogenesis (ratio of number of endothelial cells to cardiomyocytes) and decreased the myocardial fibrosis and oxidative stress. The expression of angiopoietin-1 in the heart was significantly increased by pitavastatin at 6 weeks after TAC. Conclusions: Pitavastatin has preventive effects on the progression of heart failure even in the hypertrophied heart. (Circ J 2012; 76: 1159-1168)
We examined whether granulocyte colony-stimulating factor (G-CSF) prevents cardiac dysfunction and remodeling after myocardial infarction (MI) in large animals. MI was produced by ligation of left ...anterior descending coronary artery in swine. G-CSF (10
μg/kg/day, once a day) was injected subcutaneously from 24
h after ligation for 7 days. Echocardiographic examination revealed that the G-CSF treatment induced improvement of cardiac function and attenuation of cardiac remodeling at 4 weeks after MI. In the ischemic region, the number of apoptotic endothelial cells was smaller and the number of vessels was larger in the G-CSF treatment group than in control group. Moreover, vascular endothelial growth factor was more abundantly expressed and Akt was more strongly activated in the ischemic region of the G-CSF treatment group than of control group. These findings suggest that G-CSF prevents cardiac dysfunction and remodeling after MI in large animals.
AIM： TO examine the mechanism of inactivation of the p16 gene in gallbladder cancer, and to investigate p16 alterations and their correlation with clinicopathological features.
METHODS： Specimens ...were collected surgically from 51 patients with gallbladder cancer. We evaluated the status of protein expression, loss of heterozygosity（LOH）, homozygous deletion and promoter hypermethylation using immunohistochemistry, microsatellite analysis, quantitative real-time polymerase chain reaction （PCR） and methylation-specific PCR, respectively. In addition, mutations were examined by direct DNA sequencing.
RESULTS： Homozygous deletions of the p16 gene exon2, LOH at 9p21-22, p16 promoter hypermethylation, and loss of p16 protein expression were detected in 26.0% （13/50）, 56.9% （29/51）, 72.5% （37/51） and 62.7% （32/51）, respectively. No mutations were found. LOH at 9p21 correlated with the loss of p16 protein expression （P 〈 0.05）. Homozygous deletion of the p16 gene, a combination LOH and promoter hypermethylation, and multiple LOH at 9p21 were significantly correlated with the loss of p16 protein expression （P 〈 0.05）. LOH at 9p21 and promoter hypermethylation of the p16 gene were detected in 15.4% （2/13） and 92.3% （12/13） of the tumors with homozygous deletion of the p16 gene, respectively. P16 alterations were not associated with clinicopathological features.
CONCLUSION： Our results suggest that LOH and homozygous deletion may be two distinct pathways in the inactivation of the p16 gene. Homozygous deletion, a combination of LOH and promoter hypermethylation, and multiple LOH are major mechanisms of p16 inactivation in gallbladder cancer.
Antibodies specific to a particular target molecule can be used as analytical reagents, not only for in vitro immunoassays but also for noninvasive in vivo imaging, e.g., immunoscintigraphies. In the ...latter case, it is important to reduce the size of antibody molecules in order to achieve suitable in vivo “diagnostic kinetics” and generate higher-resolution images. For these purposes, single-chain Fv fragments (scFvs; M r < 30 kDa) have greater potential than intact immunoglobulins (∼150 kDa) or Fab (or Fab′) fragments (∼50 kDa). Our recent observation of enhanced tenascin-C (Tnc) expression at sites of cardiac repair after myocardial infarction prompted us to develop a radiolabeled scFv against Tnc for in vivo imaging of heart disease. We cloned the genes encoding the heavy and light chain variable domains of the mouse anti-Tnc monoclonal antibody 4F10, and combined them to create a single gene. The resulting scFv-4F10 gene was expressed in E. coli cells to produce soluble scFv proteins. scFv-4F10 has an affinity for Tnc (K a = 3.5 × 107 M–1), similar to the Fab fragment of antibody 4F10 (K a = 1.3 × 107 M–1) and high enough to be of practical use. A cysteine residue was then added to the C-terminus to achieve site-specific 111In labeling via a chelating group. The resulting 111In-labeled scFv was administered to a rat model of acute myocardial infarction. Biodistribution and quantitative autoradiographic studies indicated higher uptake of the radioactivity at the infarcted myocardium than the noninfarcted one. Single photon emission computed tomography (SPECT) provided in vivo cardiac images that coincided with the ex vivo observations. Our results will promote advances in diagnostic strategies for heart disease.
We report the equilibrium assemblage of spinel (X
Mg
= Mg/(Fe+Mg) = 0.40-0.43, ZnO~0.58 wt%, Cr
2
O
3
= 0.39-0.44 wt%) and quartz enclosed within the core of poikiloblastic garnet in pelitic gneiss ...from the Kodaikanal region, Madurai Block, southern India. The petrogenetic grid in the KFMASH system suggests that such Zn- and Cr-poor spinel associated with quartz is an indicator of ultrahigh-temperature (UHT) metamorphism, which is confirmed by calculated peak P-T conditions using a garnet-orthopyroxene assemblage in charnockite (860-990°C and 7.5-8.5 kbar) and antiperthitic feldspar in a leucocratic layer of pelitic migmatite (T ~1000°C). Detailed observation of retrograde textures as well as mineralogical and thermobarometric data suggest that the area underwent near isobaric cooling and then decompression after the UHT event. Comparison of available P-T trajectories of the Madurai Block and adjacent areas suggests that the Kodaikanal region underwent ~1000°C UHT metamorphism similar to other domains in the Madurai Block, although the peak pressure condition is slightly lower than other areas, possibly indicating shallower crustal levels. Results of this study confirm that the Madurai Block is an example of a regional UHT terrane associated with the Pan-African orogeny attending final amalgamation of the Gondwana supercontinent.
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