PubMed Health⌕ Search

Biomedical subjects

Yutaka Sakakibara

Publications and source records attributed to Yutaka Sakakibara.

At least 19 recordsLinked to original sources
PubMed2005

Beta-adrenergic stimulation does not activate Na+/Ca2+ exchange current in guinea pig, mouse, and rat ventricular myocytes.

The effect of beta-adrenergic stimulation on cardiac Na(+)/Ca(2+) exchange has been controversial. To clarify the effect, we measured Na(+)/Ca(2+) exchange current (I(NCX)) in voltage-clamped guinea pig, mouse, and rat ventricular cells. When I(NCX) was defined as a 5 mM Ni(2+)-sensitive current in guinea pig ventricular myocytes, 1 microM isoproterenol apparently augmented I(NCX) by approximately 32%. However, this increase was probably due to contamination of the cAMP-dependent Cl(-) current (CFTR-Cl(-) current, I(CFTR-Cl)), because Ni(2+) inhibited the activation of I(CFTR-Cl) by 1 microM isoproterenol with a half-maximum concentration of 0.5 mM under conditions where I(NCX) was suppressed. Five or ten millimolar Ni(2+) did not inhibit I(CFTR-Cl) activated by 10 microM forskolin, an activator of adenylate cyclase, suggesting that Ni(2+) acted upstream of adenylate cyclase in the beta-adrenergic signaling pathway. Furthermore, in a low-extracellular Cl(-) bath solution, 1 microM isoproterenol did not significantly alter the amplitude of Ni(2+)-sensitive I(NCX) at +50 mV, which is close to the reversal potential of I(CFTR-Cl). No change in I(NCX) amplitude was induced by 10 microM forskolin. When I(NCX) was activated by extracellular Ca(2+), it was not significantly affected by 1 microM isoproterenol in guinea pig, mouse, or rat ventricular cells. We concluded that beta-adrenergic stimulation does not have significant effects on I(NCX) in guinea pig, mouse, or rat ventricular myocytes.

Adrenergic beta-Agonists↗
PubMed2005

Administration of control-released hepatocyte growth factor enhances the efficacy of skeletal myoblast transplantation in rat infarcted hearts by greatly increasing both quantity and quality of the graft.

BACKGROUND: We investigated whether simultaneous administration of control-released hepatocyte growth factor (HGF) enhances the efficacy of skeletal myoblast (SM) transplantation (Tx) through its antiapoptotic, angiogenic, and antifibrotic effects in myocardial infarction (MI). METHODS AND RESULTS: Forty-eight Lewis rats with chronic MI were divided into 4 groups. In Group I (n=14), neonatal SMs (5 x 10(6)) were transplanted in the MI area with a gelatin sheet incorporating 40 microg (1 g/L) of HGF applied. Group II (n=14) had SM Tx and placement of a saline sheet. Groups III (n=10) and IV (n=10) had culture medium injection plus HGF and saline sheet application, respectively. Four rats each from Groups I and II were sacrificed at day 1 for TUNEL assay on donor SMs. The percentage of TUNEL-positive donor cells was much lower in Group I than in Group II (P<0.05). At 4 weeks, in Group I, left ventricular diastolic dimension was smallest in echocardiography, end-systolic elastance was highest, and tau was the lowest (both P<0.0005 in ANOVA) in cardiac catheterization. Vascular density inside the graft was higher in Group I than in Group II (P<0.0001). The percentage of fibrotic area inside the graft was smaller in Group I than in Group II (P<0.001). The graft volume as estimated by fast skeletal myosin heavy chain-positive areas was approximately 7-fold larger in Group I than in Group II (P<0.0001). CONCLUSIONS: In SM Tx, HGF can greatly increase the graft volume and vascularity and reduce fibrosis inside the graft, which enhances the efficacy of SM Tx to infarcted hearts.

Animals↗
PubMed2005

Control-released hepatocyte growth factor prevents the progression of heart failure in stroke-prone spontaneously hypertensive rats.

BACKGROUND: We have developed a hepatocyte growth factor (HGF)-incorporating gelatin hydrogel sheet (HGF sheet), which was designed to release HGF more than 2 weeks in vivo. The present study investigated whether the HGF sheet could prevent the progression of heart failure in stroke-prone spontaneously hypertensive rats. METHODS: Stroke-prone spontaneously hypertensive rats at the age of 25 weeks received placement of an HGF sheet on the left ventricular free wall (HGF, n = 10) or sham-operation (control, n = 10). All animals were followed up with Doppler echocardiography during the next 4 weeks and then underwent histologic analysis. The influence of the hydrogel sheet alone was assessed by echocardiography and left ventricular pressure measurements. Survival study was performed (each group, n = 11) at the age of 30 weeks. RESULTS: There were two deaths in the control group and no deaths in the HGF group during the 4 weeks. Fractional shortening was significantly higher, and left ventricular diastolic dimension was significantly smaller in the HGF than in the control group. The slope of the peak early diastolic filling velocity and the ratio of that slope to the slope of the peak filling velocity at atrial contraction were significantly lower in the HGF than the control group. Myocardial fibrosis was lower and capillary density was significantly higher in the HGF than the control group. Placement of the hydrogel sheet alone did not affect any cardiac function compared with sham operation. The survival rate at 10 weeks after the surgery was much higher in the HGF than the control group. CONCLUSIONS: The HGF sheet improves cardiac function, reverses left ventricular remodeling, and markedly improves survival in spontaneously hypertensive rats. These beneficial effects are associated with angiogenesis and reduced fibrosis in the left ventricular myocardium.

Animals↗
PubMed2005

Characterization of spore germination of a thermoacidophilic spore-forming bacterium, Alicyclobacillus acidoterrestris.

The germination behaviors of spores of Alicyclobacillus acidoterrestris, which has been considered to be a causative microorganism of flat sour type spoilage in acidic beverages, were investigated. The spores of A. acidoterrestris showed efficient germination and outgrowth after heat activation (80 degrees C, 20 min) in Potato dextrose medium (pH 4.0). Further, the spores treated with heat activation germinated in McIlvaine buffer (pH 4.0) in the presence of a germinative substance (L-alanine) and commercial fruit juices, although not in phosphate buffer (pH 7.0). Heat activation was necessary for germination. The spores of A. acidoterrestris, which easily survived the heat treatment in acidic conditions, lost their resistance to heat during germination. Our results suggest that the models obtained from spore germination of A. acidoterrestris might be beneficial to determine adequate thermal process in preventing the growth of potential spoilage bacteria in acidic beverages.

Gram-Positive Endospore-Forming Rods↗
PubMed2004

Therapeutic angiogenesis by the controlled release of basic fibroblast growth factor for ischemic limb and heart injury: toward safety and minimal invasiveness.

We review our studies on therapeutic angiogenesis using basic fibroblast growth factor (bFGF) released in a controlled manner from biodegradable gelatin hydrogel (GH). The bFGF-GH was intramuscularly injected in rabbits with limb ischemia. The group treated with bFGF showed an increase in tissue blood flow under laser Doppler imaging and histology showed a greater vascular density compared with controls. Also, bFGF-GH was subepicardially injected into old heart infarcts in rats. In the group treated with bFGF, improved left ventricular function was shown by echocardiography and cardiac catheterization, increased regional blood flow in the peri-infarct area was detected by pinhole single-photon emission computed tomography using (201)Tl, and increased vascular density was demonstrated by histology. In rabbits with acute myocardial infarction, the heart was wrapped with the omentum (including the gastroepiploic artery) and a bFGF-GH sheet was applied. Postoperative assessment revealed rich communication from the gastroepiploic artery to the coronary artery and improved cardiac function. The controlled release of bFGF was effective for both limb and heart ischemia and is considered to be suitable for clinical use because its application in animals was feasible and safe with minimal invasiveness.

Angiography↗
PubMed2003

Transplanted skeletal myoblasts can fully replace the infarcted myocardium when they survive in the host in large numbers.

BACKGROUND: It is not clear how many skeletal myoblasts (SM) can survive and exert beneficial effects in the host myocardial infarction (MI) area. We assessed the hypothesis that a large number of SM can replace the MI area with reverse left ventricular (LV) remodeling. METHODS AND RESULTS: MI was created by left coronary artery ligation in male Lewis rats. Four weeks after ligation, 45 rats had skeletal myoblast transplantation in the MI area. They were randomized into 3 groups according to the number of SM: group I (n=15), 5 x 10(7); group II (n=15), 5 x 10(6); and group III (n=15), 5 x 10(5) cells. Donor SM were obtained from neonatal Lewis rats and directly used without expansion. Another four weeks later, all rats were sacrificed following hemodynamic assessment. All heart sections were stained with anti-fast skeletal myosin heavy chain (FSMHC) antibody to determine the spacial extent of donor myocytes. RESULTS: Four weeks after transplantation, LV diastolic dimension was decreased, fractional area change was increased, and MI size was decreased maximally in group I. Histological study showed that donor cells positive for FSMHC occupied the MI area with nearly normal wall thickness in group I, in which estimated volume of donor-derived muscle tissue was 40 mm3. In the other groups, FSMHC-positive cells were found only partly in the MI area. CONCLUSIONS: A large number of freshly isolated neonatal SM can survive in the host and fully replace the infarcted myocardium with reverse LV remodeling in rats with MI.

Animals↗
PubMed2003

Intramyocardial sustained delivery of basic fibroblast growth factor improves angiogenesis and ventricular function in a rat infarct model.

Recently we have demonstrated that the release of basic fibroblast growth factor (bFGF) from a biodegradable gelatin hydrogel carrier depends on the degradation of hydrogel in vivo. The purpose of our study was to assess whether bFGF-incorporating gelatin hydrogels induce myocardial angiogenesis and improve left ventricular function in the infarcted myocardium of rats. Studies were conducted in 22 Lewis rats after a 4-week ligation of the proximal left anterior descending coronary artery. The rats were randomized into the following two groups: the control group (n = 11) had an intramyocardial injection of saline alone, and the FGF group (n = 11) had gelatin hydrogel microspheres containing 100 microg of bFGF injected into the border zone of the infarct area after the repeat left thoracotomy. For visualization of the regional myocardial blood flow in the rat heart, (201)Tl images were taken just before and 4 weeks after the treatment using a 4-head single photon emission computed tomography scanner with pinhole collimators. Left ventricular function was also assessed with echocardiography and a micromanometer-tipped catheter. Finally, the extent of myocardial angiogenesis was evaluated quantitatively in the postmortem analysis. The (201)Tl defect score in the control group remained unchanged before and after the treatment, whereas it decreased significantly in the FGF group. Both regional and global left ventricular function was significantly better in the FGF group compared with the control group. The vascular density in the border zone of the infarct in the FGF group was significantly higher than that in the control group. In conclusion, intramyocardial injection of bFGF-impregnated gelatin hydrogels induces functionally significant angiogenesis and improves left ventricular systolic and diastolic function in the infarcted myocardium of rats.

Animals↗
PubMed2003

A pig model of chronic heart failure by intracoronary embolization with gelatin sponge.

BACKGROUND: We produced a large-animal model of left ventricular (LV) failure induced by transcatheter embolization of the left coronary artery using a gelatin sponge. METHODS: Fourteen male pigs underwent transcatheter embolization of the left anterior descending artery (LAD) using gelatin sponge to produce anteroapical myocardial infarction. Coronary angiography was performed 1 week after the coronary embolization. The animals were followed up with echocardiography and LV pressure-volume study for the subsequent 8 weeks, and the data were compared with those of the control group (n = 13). RESULTS: The procedure mortality was 2 of 14 (14%). Coronary angiography revealed the occluded LAD was recanalized with poor run-off. The LV end-diastolic dimension progressively increased (control versus myocardial infarction: 39 +/- 2 mm versus 49 +/- 4 mm, p < 0.001 at week 4; and 40 +/- 2 mm versus 57 +/- 6 mm, p < 0.001 at week 8). Fractional area change decreased over 8 weeks (77% +/- 10% versus 43% +/- 6%, p < 0.001 at week 4; and 77% +/- 10% versus 40% +/- 8%, p < 0.001 at week 8). End-systolic elastance progressively decreased over 8 weeks (3.04 +/- 0.73 mm Hg/mL versus 1.54 +/- 0.51 mm Hg/mL, p < 0.0001 at week 4; and 2.88 +/- 0.44 mm Hg/mL versus 1.05 +/- 0.21 mm Hg/mL, p < 0.001 at week 8). The plasma levels of brain natriuretic peptide were significantly higher in the study group (543 +/- 131 pg/mL versus 1,321 +/- 364 pg/mL, p < 0.001 at week 4; and 610 +/- 152 pg/mL versus 1,523 +/- 232 pg/mL, p < 0.001 at week 8). CONCLUSIONS: This pig model of chronic heart failure is reliable, reproducible, and amenable to investigate other surgical procedures.

Animals↗
PubMed2003

Toward surgical angiogenesis using slow-released basic fibroblast growth factor.

OBJECTIVE: Therapeutic angiogenesis using basic fibroblast growth factor (bFGF) in coronary artery disease has been documented in a number of papers. However, the effectiveness is discrepant among documents. In this study, we evaluated the distribution of bFGF in the rat heart by different administration methods, and investigated the efficacy of slow-released administration of bFGF using biodegradable hydrogel microspheres (bFGF microspheres) in a pig infarction model toward an enhanced coronary bypass surgery. METHODS: Heart failure due to myocardial infarction was induced in rats and pigs. In the rat study, free form of bFGF (central venous injection, intracoronary injection, and intramyocardial administration) and bFGF microspheres (intramyocardial administration) were given 4 weeks later. The remaining radioactivity of bFGF in the hearts was estimated 1, 24, and 72 h later. On the other hand, the pigs were randomized into two groups 4 weeks after myocardial infarction. While the control group (n=8) had gelatin hydrogel microspheres with saline, the FGF group (n=8) received bFGF microspheres in the left ventricular (LV) wall. RESULTS: In the rat study, after intramyocardial administration of bFGF microspheres, more bFGF remained in the rat heart 72 h later compared with the other methods (P<0.0001). In the pig study, 4 weeks after the treatment, the FGF group had smaller LV diastolic diameter (48.7+/-5.3 vs. 56.7+/-5.2 mm, P<0.01) than the control group. LV end-systolic elastance was higher in the FGF group (2.96+/-1.2 vs. 1.06+/-0.3 mmHg/ml, P<0.01). In microscopic examinations, many neovessels were found in and around the scar tissue, and the vascular density in the FGF group was significantly higher (61.5+/-18.3 vs. 153.0+/-29.0/mm2, P<0.01). In addition, the infarcted LV walls were less expanded and more thickened in the FGF group. CONCLUSIONS: Biodegradable hydrogel microspheres with bFGF improved LV function and inhibited LV remodeling by angiogenesis in pigs with chronic myocardial infarction. bFGF microspheres into ischemic myocardium may revascularize small ungraftable vessels and may potentially increase distal run-off when applied in coronary bypass surgery.

Animals↗
PubMed2003

Improved therapeutic efficacy in cardiomyocyte transplantation for myocardial infarction with release system of basic fibroblast growth factor.

Several studies have demonstrated that cell transplantation was effective for the therapy of myocardial infarction. However, little care has been taken for the blood supply indispensable to cell transplantation. This study is an investigation to evaluate the feasibility of in advance angiogenesis by gelatin microspheres incorporating basic fibroblast growth factor (bFGF) for the transplantation therapy of cardiomyocytes with an ischemic cardiomyopathy model. Rats with myocardial infarction received the intramuscular injection of culture medium (Control), or that containing fetal cardiomyocytes (TX) or gelatin microspheres incorporating bFGF (FGF), and gelatin microspheres incorporating bFGF plus fetal cardiomyocytes 1 week later (FGF-TX). The left ventricle (LV) function of rat hearts was assessed by echocardiography and cardiac catheterization 4 weeks later. The LV maximum time-varying elastance was significantly higher in the FGF-TX group than in other groups. The combination of bFGF-induced angiogenesis and cardiomyocyte transplantation is a promising procedure to improve the LV function in rats with myocardial infarction.

Animals↗
PubMed2003

Fluoreometric behavior of a novel bis-acridine orange bound to double stranded DNA.

Novel bis-acridine orange (1) was synthesized from Fmoc-Lys(Boc)-OH and Fmoc-Lys(AO)-OH (AO: acridine orange), with the 9-position of acridine orange (AO) linked to the epsilon-amino moiety of lysine, on the peptide synthesizer. Bis-acridine orange (1) yielded a very weak fluorescence in an aqueous media due to the intramolecular stacking, but its fluorescence was enhanced over 200-times upon binding to double-stranded DNA, irrespective of the DNA sequences. Circular dichroism (CD) spectra showed that 1 binds to double stranded DNA in its stacked conformation, concomitant with fluorescence enhancement.

Acridine Orange↗
PubMed2002

Combined procedure of surgical repair and cell transplantation for left ventricular aneurysm: an experimental study.

BACKGROUND: This study was designed to investigate the efficacy of the combined procedure of left ventricular (LV) repair and fetal cardiomyocyte transplantation (CM-TX) in a rat myocardial infarction model. METHODS AND RESULTS: A moderate-sized LV aneurysm was created by proximal ligation of the left coronary artery in 47 Lewis rats. Four weeks later, they were underwent another operation and received culture medium injection (n=10; group I), fetal CM-TX (n=10; group II), purse-string LV repair with culture medium injection (n=14; group III), or LV repair with fetal CM-TX (n=13; group IV). They were echocardiographically followed-up during the subsequent 4 weeks, and cardiac catheterization was performed in the final week. In the late period, LV dimension in group IV was smaller than that in group III (end-diastolic dimension, 0.92+/-0.02 versus 1.01+/-0.03 cm, P=0.0090; end-systolic dimension, 0.62+/-0.02 versus 0.74+/-0.04 cm, P=0.0093; at the fourth week), although they initially showed similar decreases in both groups. At the final week, end-systolic elastance was higher in group IV than in groups I, II, or III (0.61+/-0.10 versus 0.19+/-0.03, 0.30+/-0.09, 0.33+/-0.07 mm Hg/ micro L, P=0.0002, 0.0037, and 0.0042, respectively). CONCLUSIONS: Fetal CM-TX exerted preventive effects against late LV dilation and dysfunction after LV repair in the rat model. The results suggest that repair surgery combined with fetal CM-TX may enhance the surgical benefits for patients with LV aneurysm in the long term.

Animals↗
PubMed2002

Cardiomyocyte transplantation does not reverse cardiac remodeling in rats with chronic myocardial infarction.

BACKGROUND: Several reports have documented the potential benefits of cell transplantation as an alternative to cardiac transplantation. This study was designed to investigate whether cardiomyocyte transplantation is effective in rats with chronic myocardial infarction. METHODS: Syngeneic Lewis rats were used in this study. Chronic myocardial infarction was induced in rats by ligating the left anterior descending artery. Four weeks later, after left ventricular (LV) dysfunction with akinetic regions was confirmed by echocardiography, the rats were randomized into two groups: a group that received fetal cardiomyocyte transplantation (TX group; n = 11); and a group that received an intramyocardial injection of culture medium only (control group; n = 12). RESULTS: Four weeks after treatment, the TX group had smaller end-systolic dimension (LVDs) (7.5 +/- 0.9 vs 8.9 +/- 0.8 mm, p < 0.01) and better fractional shortening (FS) (26.2 +/- 5.9 vs 17.7% +/- 5.1%, p < 0.01) than the control group. However, there were no differences in LV end-diastolic dimension, LVDs, and FS between baseline and post-treatment values in the TX group. In addition, plasma levels of atrial natriuretic peptide were not significantly different between the two groups 4 weeks after treatment. In microscopic examination, small amounts of transplanted cardiomyocytes were found only in the periinfarct area, not in the center of scar area, and a thicker ventricular wall in the infarct area was detected in the TX group. CONCLUSIONS: Fetal cardiomyocyte transplantation prevented, but did not reverse, cardiac remodeling that was accompanied with heart failure in myocardial infarction rats. Further investigation is warranted for optimal clinical application to the failing heart.

Animals↗
PubMed2002

High-rate denitrification and SS rejection by biofilm-electrode reactor (BER) combined with microfiltration.

In this study, a multi-cathode biofilm-electrode reactor (BER) combined with microfiltration (MF) was investigated using a laboratory-scale experimental apparatus for treatment of nitrate-contaminated water. The multi-cathode electrodes were composed of multiple-granular activated carbons (GACs). GACs attached to each cathode to enlarge surface area of electrodes and to attach bacteria quickly and firmly. In BER, H2 gas is produced by applying electric current, which serves as an electron donor in biological reduction of nitrate to N2 gas. Since some suspended solids were escaping from BER, MF membrane with plate modules and a pore size of 0.2 microm was placed after BER. Experimental results demonstrated that it was possible to operate the multi-cathode BER with high denitrification rates and hydraulic retention time (HRT) as low as HRT = 20 min. The denitrification rate was enhanced by 3-60 times in comparison with former studies. MF membrane successfully rejected the bacteria escaping from BER, so that the effluent concentration of SS was kept below 1 mg SS/l throughout the experiment. It was also possible to operate MF membrane at flux 2-9 times higher and pressure 2.5-31 times smaller than in former studies. This higher performance was mainly brought about by using biofilm and H2 gas as an electron donor. Also, an economic evaluation of BER/MF was included, showing the feasibility of this process. The present BER/MF process is considered advantageous for the enhanced treatment of nitrate-polluted groundwater.

Biofilms↗
PubMed2002

Prevascularization with gelatin microspheres containing basic fibroblast growth factor enhances the benefits of cardiomyocyte transplantation.

OBJECTIVE: The effects of cell transplantation on the ischemic failing heart have already been documented. However, the area in and around infarct regions is not a good environment for cells to survive in because they are exposed to poor conditions in which certain requirements cannot be adequately supplied. We therefore designed a study to investigate the efficacy of prevascularization in ischemic regions before cell transplantation. METHODS: Rats with myocardial infarction were randomized into 4 groups: 11 rats received a culture medium injection to the left ventricular wall (control group), 11 received fetal cardiomyocyte transplantation (TX group), 11 received gelatin hydrogel microspheres incorporating basic fibroblast growth factor (FGF group), and 11 received basic fibroblast growth factor pretreatment sequentially, followed by cardiomyocyte transplantation (FGF-TX group). Four weeks later, left ventricular function was assessed by means of echocardiography and cardiac catheterization. RESULTS: In the FGF and FGF-TX groups neovascularization was found in the scar tissue 1 week later. The TX, FGF, and FGF-TX groups showed better fractional shortening than the control group (TX, FGF, FGF-TX, and control: 28% +/- 4.4%, 24% +/- 8.6%, 27% +/- 7.3%, and 17% +/- 4.6%, respectively; P <.01). Left ventricular maximum time-varying elastance was higher in the FGF-TX group than in the TX and FGF groups (FGF-TX, TX, and FGF: 0.52 +/- 0.23, 0.30 +/- 0.08, and 0.27 +/- 0.20 mm Hg/microL, respectively; P <.01). Histologically, more transplanted cells survived in the FGF-TX group than in the TX group. CONCLUSIONS: Prevascularization with basic fibroblast growth factor-incorporated microspheres enhances the benefits of cardiomyocyte transplantation. We expect that this system will contribute to regeneration medicine through its extensive application to other growth factors.

Animals↗
PubMedDate not supplied

Quantitative fluorine 18 deoxyglucose uptake by myocardial positron emission tomography in rats.

BACKGROUND: In vivo quantitative assessment of positron emission tomography (PET) with 2-deoxy-2-[fluorine 18]fluorodeoxyglucose (FDG) for rat heart has not been explored because of the theoretical limitation of spatial resolution. Our objective was to assess whether FDG uptake measured by PET is correlated with tissue radioactivity of FDG in rat heart directly measured by an automated gamma counter. METHODS AND RESULTS: Ten Sprague-Dawley rats were used for echocardiographic assessment and FDG-PET. Rats were sacrificed immediately after PET scanning, and the radioactivity of FDG in 4 segmental tissue samples of the middle transverse section was measured. Quantitative PET values in a total of 40 regions of interest, in which partial volume effect was corrected based on the phantom study and wall thickness obtained by echocardiogram, were compared with radioactivity of the corresponding 40 tissue samples. Linear regression analysis revealed that tissue radioactivity of FDG was well correlated with the quantitative PET value (Y = 1.17X; r = 0.985, P <.0001). CONCLUSIONS: Quantitative FDG-PET for rat heart is a reliable approach for assessing glucose metabolism in vivo after correction is made for partial volume effect. These results can be used for various models of heart disease with repeated studies over the disease process in the same animal.

Animals↗
PubMedDate not supplied

A rat model of ischemic cardiomyopathy for investigating left ventricular volume reduction surgery.

OBJECTIVE: The effects of volume reduction surgery (VRS) for ischemic cardiomyopathy are not fully understood. The development of a proper animal model will help to resolve this issue. METHODS: Study 1 (Noninvasive study): Twenty-six rats developed large akinetic left ventricular (LV) aneurysms or ischemic cardiomyopathy after anterior descending artery ligation (first surgery). Four weeks after the surgery, 13 rats underwent volume reduction surgery (second surgery) (VRS group), while 13 underwent rethoracotomy alone (sham group). Before the first surgery, and before and after the second surgery, the LV dimensions were measured by echocardiography, and the heart rate and systolic blood pressure were recorded by the tail cuff method. Study 2 (Invasive study): In 7 rats undergoing the VRS and 9 undergoing the sham operation, LV pressure was measured with a manometer-tipped catheter, immediately before and after the second surgery. RESULTS: Study 1: All rats survived the second surgery, after which LV end-diastolic diameter decreased and LV fractional shortening increased (both p < 0.001) in the VRS group. This group also increased heart rate after the second surgery (p < 0.05). Study 2: There were no differences in LV end-systolic or end-diastolic pressure between the two groups before and after the second surgery. CONCLUSIONS: This model enables reproducible physiological evaluation of the LV after VRS, and since the rats show postoperative survival, it provides a useful tool for various investigations.

Animals↗