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: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:This dataset is a time series (1 hour [h], 4 hours, 24 hours, 48 hours, 1 week [w], and 8 weeks) intended to compare normal functioning left ventricles [lv + lv2] with infarcted [ilv] and non-infarcted left ventricles [nilv]. ilv samples are taken from the region between the LAD artery and the apex on a mouse with myocardial infarction. Lv2 samples are from the same region in a sham operated mouse. Nilv samples are taken from the region above the infartion and the left ventricle [lv] samples mimic that region in a sham mouse. The lv and lv2 samples can be compared as both are from normal functioning hearts. For more information visit http://cardiogenomics.med.harvard.edu/groups/proj1/pages/mi_home.html
Project description:C57BL/6 J mice were subjected to ligation of the left anterior descending coronary artery. Ly6Chi macrophages and Ly6Clo macrophages were collected from infarcted hearts at 3 days after MI.
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).
Project description:Although bone marrow-derived mononuclear cells (BMNC) have been extensively used in cell therapy for cardiac diseases, little mechanistic information is available to support reports of their efficacy. To address this shortcoming, we compared structural and functional recovery and associated global gene expression profiles in post-ischaemic myocardium treated with BMNC transplantation. BMNC suspensions were injected into cardiac scar tissue 10 days after experimental myocardial infarction. Six weeks later, mice undergoing BMNC therapy were found to have normalized antibody repertoire and improved cardiac performance measured by ECG, treadmill exercise time and echocardiography. After functional testing, gene expression profiles in cardiac tissue were evaluated using high-density oligonucleotide arrays. Expression of more than 18% of the 11981 quantified unigenes was significantly altered in the infarcted hearts. BMNC therapy restored expression of 2099 (96.2%) of the genes that were altered by infarction but led to altered expression of 286 other genes, considered to be a side effect of the treatment. Transcriptional therapeutic efficacy, a metric calculated using a formula that incorporates both recovery and side effect of treatment, was 73%. In conclusion, our results confirm a beneficial role for bone marrow-derived cell therapy and provide new information on molecular mechanisms operating after BMNC transplantation on post ischemic heart failure in mice. We compared RNA samples extracted from whole hearts of infarcted mouse myocardium treated with bone marrow mononuclear cells control with untreated infarcted and control mice samples by analyzing hybridization to AECOM 32k mouse microarrays (http://microarray1k.aecom.yu.edu/) spotted with Operon version 3.0 70-mer oligonucleotides. The hybridization protocol and the slide type were uniform throughout the entire experiment to minimize the technical noise. Treated, control (sham) and infarcted red-labeled heart samples were hybridized against an in-house prepared green-labeled universal mouse reference.