Heart ; Myocardium ; cytology ; Stem Cells

Humans ; Myocardium ; cytology ; Stem Cells

OBJECTIVE: We wanted to evaluate the effect of the number of diffusion-sensitizing gradient directions on the image quality for evaluating myocardial anisotropy and fiber tracking by using in vitro diffusion tensor MR imaging (DT-MRI). MATERIALS AND METHODS: The DT-MR images, using a SENSE-based echoplanar imaging technique, were acquired from ten excised porcine hearts by using a 3T MR scanner. With a b-value of 800 s/mm2, the diffusion tensor images were obtained for 6, 15 and 32 diffusion-sensitizing gradient directions at the midventricular level. The number of tracked fibers, the fractional anisotropy (FA), and the length of the tracked fibers were measured for the quantitative analysis. Two radiologists assessed the image quality of the fiber tractography for the qualitative analysis. RESULTS: By increasing the number of diffusion-sensitizing gradient directions from 6 to 15, and then to 32, the FA and standard deviation were significantly reduced (p < 0.01), and the number of tracked fibers and the length of the tracked fibers were significantly increased (p < 0.01). The image quality of the fiber tractography was significantly increased with the increased number of diffusion-sensitizing gradient directions (p < 0.01). CONCLUSION: The image quality of in vitro DT-MRI is significantly improved as the number of diffusion-sensitizing gradient directions is increased.
Animals ; Anisotropy ; Diffusion Magnetic Resonance Imaging/*methods ; Myocardium/*cytology ; Swine

The proliferation of cardiac fibroblasts (CFs) is a key pathological process in the cardiac remodeling. To establish an objective, quantitative method for the analysis of cell proliferation and cell cycle, we applied the high-content screening (HCS) and flow cytometry (FCM) techniques. CFs, isolated by enzyme digestion from newborn C57BL/6J mice, were serum starved for 12 h and then given 10% fetal bovine serum (FBS) for 24 h. Followed by BrdU and DAPI (or 7-AAD) staining, CFs proliferation and cell cycle were analyzed by HCS and FCM, respectively. Discoidin domain receptor 2 (DDR2) staining indicated that the purity of isolated CFs was over 95%. (1) HCS analysis showed that the ratio of BrdU-positive cells was significantly increased in 10% FBS treated group compared with that in serum-free control group [(12.96 ± 0.67)% vs (2.77 ± 0.33)%; P < 0.05]. Cell cycle analysis showed that CFs in G0/G1 phase were diploid, and CFs in S phase were companied with proliferation, DNA replication and enlarged nuclei; CFs in G2 phase were tetraploid, and CFs in M phase produced two identical cells (2N). (2) FCM analysis showed that the ratio of BrdU-positive cells was increased in 10% FBS treated group compared with that in the control group [(11.10 ± 0.42)% vs (2.22 ± 0.31)%; P < 0.05]; DNA content histogram of cell cycle analysis indicated that the platform of S phase elevated in 10% FBS group compared with control group. (3) There were no differences between the two methods in the results of proliferation and cell cycle analysis. In conclusion, HCS and FCM methods are reliable, stable and consistent in assessment of the proliferation and cell cycle in CFs.
Animals ; Cell Cycle ; Cell Proliferation ; Fibroblasts ; cytology ; Flow Cytometry ; Mice ; Mice, Inbred C57BL ; Mitosis ; Myocardium ; cytology

To approach the method of isolation of tolerant human atrial myocytes, single myocytes were isolated by modified procedure of enzymatic dissociation with protease (type XXIV) and collagenase (type V). L-type calcium channel current (I(Ca-L)), sodium current (I(Na)), transient outward potassium current (I(to1)), and inward rectifier potassium current (I(K1)) in isolated atrial myocytes were recorded by using whole-cell patch-clamp techniques. Single cardiocytes isolated by this method were smooth, well-striated and rod-shaped. The yields of recordable myocytes, which viable and calcium-tolerant for electrophysiological studies, were 50%-60% of the total isolated cells. Compared with other isolation methods, this method was simple and steady, but with yield of a great number of qualified myocytes. The currents recorded in these cells were functional and active. Our research suggests that the myocytes isolated by the described method in this paper have normal electrophysiological function and are appropriate for patch-clamp experiments.
Cell Separation ; methods ; Humans ; Myocardium ; cytology ; Myocytes, Cardiac ; cytology ; Patch-Clamp Techniques

Bone Marrow Cells ; cytology ; Fibroblasts ; cytology ; metabolism ; Fibrosis ; Humans ; Myocardium ; pathology

In developed countries, in which people have nutrient-rich diets, convenient environments, and access to numerous medications, the disease paradigm has changed. Nowadays, heart failure is one of the major causes of death. In spite of this, the therapeutic efficacies of medications are generally unsatisfactory. Although whole heart transplantation is ideal for younger patients with heart failure, many patients are deemed to be unsuitable for this type of surgery due to complications and/or age. The need for therapeutic alternatives to heart transplantation is great. Regenerative therapy is a strong option. For this purpose, several cell sources have been investigated, including intrinsic adult stem or progenitor cells and extrinsic pluripotent stem cells. Most intrinsic stem cells seem to contribute to a regenerative environment via paracrine factors and/or angiogenesis, whereas extrinsic pluripotent stem cells are unlimited sources of cardiomyocytes. In this review, we summarize the various strategies for using regenerative cardiomyocytes including our recent progressions: non-genetic approaches for the purification of cardiomyocytes and efficient transplantation. We expect that use of intrinsic and extrinsic stem cells in combination will enhance therapeutic effectiveness.
Animals ; Embryonic Stem Cells/cytology ; Humans ; Myocardium/*cytology/*metabolism ; Myocytes, Cardiac/*cytology ; *Regeneration ; Stem Cell Transplantation ; Tissue Engineering

Objective To identify and verify the distribution of Telocytes derived from heterogeneous interstitial cells in the vital organs of ApoE mice.Methods Heart,kidney,and liver tissues were harvested from ApoE adult mice. Immunohistochemical assays were performed by using different immunobiological markers.Results Telocytes were found in these vital organs. The expressions of immunobiological markers differed among different organs. CD34,CD117,and CD28 were positively expressed in Telocytes in cardiac tissue;CD117 and plateled-derived growth factor-Α were negatively expressed in Telocytes in renal tissue;and CD117 and plateled-derived growth factor receptor-Α had negative expression in Telocytes in hepatic tissue. Furthermore,the distribution of Telocytes also differed in the same organ.Conclusions Telocytes exist in the vital organs of ApoE mice,as demonstrated by immunohistochemisty assay. The expressions of immunobiological markers differ among Telocytes in different organs.
Animals ; Antigens, CD34 ; metabolism ; CD28 Antigens ; metabolism ; Kidney ; cytology ; Liver ; cytology ; Mice ; Mice, Knockout, ApoE ; Myocardium ; cytology ; Proto-Oncogene Proteins c-kit ; metabolism ; Telocytes ; cytology

OBJECTIVETo study the effects of skeletal muscle satellite cells implanted into infarcted myocardium on the volume of remnant myocytes.

METHODSThirty-six adult mongrel canines were divided randomly into implantation group and control group. In the implantation group, skeletal muscle satellite cells taken from the gluteus maximus muscles of the dogs were cultured, proliferated and labeled with 4',6-diamidino-2-phenylindone (DAPI) in vitro. In both groups, a model of acute myocardial infarction was established in every dog. In the implantation group, each dog was injected with M199 solution containing autologous skeletal muscle satellite cells. The dogs in the control group received M199 solution without skeletal muscle satellite cells. The dogs of both groups were killed 2, 4 and 8 weeks after implantation (six dogs in a separate group each time). Both infarcted myocardium and normal myocytes distal from the infracted regions isolated were observed under optical and fluorescent microscope. Their volumes were determined using a confocal microscopy image analysis system and analyzed using SAS. A P < 0.05 was considered significant.

RESULTSA portion of the implanted cells differentiated into muscle fiber with striations and were connected with intercalated discs. Cross-sectional area and cell volume were increased in normal myocardium. Hypertrophy of remnant myocytes in the infarcted site after skeletal muscle cell implantation was much more evident than in the control group. Cross-sectional area, cell area and cell volume differed significantly from those of the control group (P < 0.05). Hypertrophy of the cells occurred predominantly in terms of width and thickness, whereas cell length remained unchanged.

CONCLUSIONSkeletal muscle satellite cells implanted into infarct myocardium, could induce the hypertrophy of remnant myocyte cells in the infarcted site and could also aid in the recovery of the contractile force of the infarcted myocardium.

Animals ; Cell Size ; Dogs ; Myocardial Infarction ; pathology ; Myocardium ; pathology ; Myocytes, Cardiac ; cytology ; Random Allocation ; Satellite Cells, Skeletal Muscle ; cytology ; physiology

OBJECTIVETo study the effect of different access routes on autologous satellite cell implantation to stimulate myocardial regeneration.

METHODSSatellite cells were procured from skeletal muscle (gluteus max) of adult mongrel canine, cultured, proliferated and labeled with 4', 6-diamidino-2-phenylindone (DAPI) in vitro. The cells were autologously implanted into the site of acute myocardial infarction by local injection or perfusion through the ligated distal left anterior descending coronary artery. Specimens were harvested 2, 4 and 8 weeks later for histological study.

RESULTSThe labeling efficiency of satellite cells with DAPI was close to 100%. Fluorescent cells were found at the infarcted zone, papillary muscle and local injection site. Some of these cells had progressively differentiated into striated muscle fibers connected to intercalated discs. The infant cells appeared different from the mature myocardium under an electron microscope. Satellite cells implanted by perfusion through the coronary artery were arranged in order of consistency with host myocardial fibers. The satellite cells, implanted by local injection, were found growing in a disordered way.

CONCLUSIONSatellite cells, implanted by coronary artery perfusion, can progressively differentiate into striated muscle fibers, arranging in order and disseminating over the infarcted zone. This approach seems more favorable for the recovery of myocardial contractile function than that of local injection.

Animals ; Cell Differentiation ; physiology ; Dogs ; Myocardial Infarction ; pathology ; therapy ; Myocardium ; cytology ; Regeneration ; Satellite Cells, Skeletal Muscle ; cytology ; transplantation ; Transplantation, Autologous