Direct stem cell injection (i.e., intravascular or intramyocardial) is typically associated with poor cell retention [35,36] and so biomaterial constructs have been developed to overcome this challenge (reviewed in [37–42]).
These efforts have been met with varying levels of success and include the following approaches.
Stem cell transplantation holds promise as a therapeutic approach for the repair of damaged myocardial tissue.
One challenge of this approach is efficient delivery and long-term retention of the stem cells.
Ischemic heart disease is the result of an imbalance between myocardial blood flow and the metabolic demand of the myocardium that may eventually lead to infarction(s) [1,2].
Following myocardial infarction, pharmacological therapies (e.g., vasodilators, thrombolytics and antihypertensives) and cardiovascular intervention therapies (e.g., angioplasty, atherectomy, stenting and coronary artery bypass grafts) can improve blood supply to the heart.
Unlike mature dermis, this tissue matrix is comprised of relatively high concentrations of type III collagen (20–30%) in addition to type I collagen (70–80%; company communication ).
This composition of fibrillar collagens is similar to that of the mature heart .
PEG has been utilized due to the inert quality of the material as well as the relative ease with which mechanical and physical properties can be tailored.MSCs cultured in this way express CD73, CD90 and CD105 (Supplementary Figure 1) (see online at and with proper stimulation are able to differentiate down the chondrogenic, osteogenic and adipogenic pathways.Experiments were performed using passages 7–10 and all cultures were maintained at 37°C in 5% CO studies, pieces of Tissue Mend matrix (2 × 2 × 0.8 mm) were placed in wells of 24-well plates and hydrated with α-MEM-complete culture medium.Tuning the excitation wavelength to 890 nm, a 445/1 nm narrow band pass emission filter (Thin Film Imaging, Greenfield, MA, USA) was used to detect the SHG signal of collagen in the backscattered mode using a H7422P Ga As P photon counting photomultiplier tube (Hamamatsu Photonics KK, Shizuoka, Japan).For detection of Cell Tracker Red, a 580 nm long pass emission filter (Thin Film Imaging) was used.Briefly, cells were cultured on a 0.1% gelatin (Sigma-Aldrich, St Louis, MO, USA) pretreated flask containing α-minimum essential media (MEM)-complete.