Project description:Vascularization and efficient perfusion are long-standing challenges in cardiac tissue engineering. Here, we engineer perfusable microvascular constructs, wherein human embryonic stem cell-derived endothelial cells (hESC-ECs) are seeded both into patterned microchannels and the surrounding collagen matrix. In vitro, the hESC-ECs lining the luminal walls readily sprout and anastomose with de novo-formed endothelial tubes in the matrix under flow. When implanted on infarcted rat hearts, the perfusable microvessel grafts integrate with coronary vasculature to a greater degree than non-perfusable self-assembled constructs at 5 days post-implantation. Optical microangiography imaging reveal that perfusable grafts have 6-fold greater vascular density, 2.5-fold higher vascular velocities and >20-fold higher volumetric perfusion rates. Implantation of perfusable grafts containing additional hESC-derived cardiomyocytes show higher cardiomyocyte and vascular density. Thus, pre-patterned vascular networks enhance vascular remodeling and accelerate coronary perfusion, potentially supporting cardiac tissues after implantation. These findings should facilitate the next generation of cardiac tissue engineering design.
Project description:microRNAs control cardiac remodeling post myocardial infarction, though the cellular and molecular mechanisms remain unclear. We used microarrays to examine microRNA profiles in mice hearts 21 days after ligation of left anterior descending coronary artery (LAD) versus sham control.
Project description:Necroptosis has been recognized in heart failure (HF). In this study, we investigated detailed necroptotic signalling in infarcted and non-infarcted areas separately and its mechanistic link with main features of HF. Post-infarction HF in rats was induced by left coronary occlusion (60 minutes) followed by 42-day reperfusion. Heart function was assessed echocardiographically. Molecular signalling and proposed mechanisms (oxidative stress, collagen deposition and inflammation) were investigated in whole hearts and in subcellular fractions when appropriate. In post-infarction failing hearts, TNF and pSer229-RIP3 levels were comparably increased in both infarcted and non-infarcted areas. Its cytotoxic downstream molecule p-MLKL, indicating necroptosis execution, was detected in infarcted area. In non-infarcted area, despite increased pSer229-RIP3, p-MLKL was present in neither whole cells nor the cell membrane known to be associated with necroptosis execution. Likewise, increased membrane lipoperoxidation and NOX2 levels unlikely promoted pro-necroptotic environment in non-infarcted area. Collagen deposition and the inflammatory csp-1-IL-1β axis were active in both areas of failing hearts, while being more pronounced in infarcted tissue. Although apoptotic proteins were differently expressed in infarcted and non-infarcted tissue, apoptosis was found to play an insignificant role. p-MLKL-driven necroptosis and inflammation while inflammation only (without necroptotic cell death) seem to underlie fibrotic healing and progressive injury in infarcted and non-infarcted areas of failing hearts, respectively. Upregulation of pSer229-RIP3 in both HF areas suggests that this kinase, associated with both necroptosis and inflammation, is likely to play a dual role in HF progression.
Project description:We have observed that DBA/2J and C57Bl6/N mice exhibit different responses to permanent coronary artery ligation, with mice in a C57 background having about a 14-fold increase in cardiomyocyte S-phase activity as compared to DBA mice. We mapped the responsible gene to the distal arm of Chromosome 3 in the C57 background. We then RNA-Seq analyses on hearts from normal and infarcted DBA and C57 mice, with the hope of identifying candidate genes within the region of interest on the distal arm of Chromosome 3 which are differentially expressed. These genes identified Tnni3k as a potential candidate contributing to the elevated S-phase phenotype.
Project description:Vascularization and efficient perfusion are long-standing challenges in cardiac tissue engineering. Here we report engineered perfusable microvascular constructs, wherein human embryonic stem cell-derived endothelial cells (hESC-ECs) are seeded both into patterned microchannels and the surrounding collagen matrix. In vitro, the hESC-ECs lining the luminal walls readily sprout and anastomose with de novo-formed endothelial tubes in the matrix under flow. When implanted on infarcted rat hearts, the perfusable microvessel grafts integrate with coronary vasculature to a greater degree than non-perfusable self-assembled constructs at 5 days post-implantation. Optical microangiography imaging reveal that perfusable grafts have 6-fold greater vascular density, 2.5-fold higher vascular velocities and >20-fold higher volumetric perfusion rates. Implantation of perfusable grafts containing additional hESC-derived cardiomyocytes show higher cardiomyocyte and vascular density. Thus, pre-patterned vascular networks enhance vascular remodeling and accelerate coronary perfusion, potentially supporting cardiac tissues after implantation. These findings should facilitate the next generation of cardiac tissue engineering design.
Project description:Mice are 14 days post-mI/R (10 weeks old) on a C57Bl/6N background strain, hearts were collected at ZT15, following administration of saline placebo, sleeptime captopril (ZT01), or waketime captopril (ZT11) I.P. from day 7-14 post-mI/R. The microarray approach allows the investigation of gene expression changes of all genes in placebo vs. sleeptime vs. waketime vs. sham hearts.
Project description:Myocardial infarction (MI) is the leading cause for hear failure (HF). Following MI, the non-infarcted region of left ventricle (LV) is critical for maintaining heart function, and disruption of the LV contributes greatly to post-MI HF. Transcriptomic profiling by high-throughput sequencing was performed in a chronic HF pig model, to explore the molecular changes in the post-MI LV related to cardiovascular deterioration. Samples were taken from heart tissue of MI-induced pigs and from control pigs not subjected to MI. Regions of the heart where samples were taken included the site of ischemia (LV ischemia), area bordering ischemia (LV border), area remote to ischemia (LV remote) and the right ventricle (RV).