Files/.DS_Store __MACOSX/Files/._.DS_Store Files/Article.pdf J. Exp. Med.  The Rockefeller University Press • XXXXXXXXXX/2002/02/375/07 $5.00 Volume 195, Number 3, February 4, XXXXXXXXXX–381...

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Files/.DS_Store __MACOSX/Files/._.DS_Store Files/Article.pdf J. Exp. Med.  The Rockefeller University Press • 0022-1007/2002/02/375/07 $5.00 Volume 195, Number 3, February 4, 2002 375–381 http://www.jem.org/cgi/content/full/195/3/375 Brief Definitive Report 375 Evidence for a Role of Mast Cells in the Evolution to Congestive Heart Failure Masatake Hara, 1 Koh Ono, 1 Myung-Woo Hwang, 1 Atsushi Iwasaki, 1 Masaharu Okada, 1 Kazuki Nakatani, 2 Shigetake Sasayama, 1 and Akira Matsumori 1 1 Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8397, Japan 2 Second Department of Anatomy, Osaka City University Medical School, Osaka 545-8585, Japan Abstract Mast cells are believed to be involved in the pathophysiology of heart failure, but their precise role in the process is unknown. This study examined the role of mast cells in the progression of heart failure, using mast cell-deficient (WBB6F1-W/W v ) mice and their congenic controls (wild-type [WT] mice). Systolic pressure overload was produced by banding of the abdominal aorta, and cardiac function was monitored over 15 wk. At 4 wk after aortic constriction, car- diac hypertrophy with preserved left ventricular performance (compensated hypertrophy) was observed in both W/W v and WT mice. Thereafter, left ventricular performance gradually de- creased in WT mice, and pulmonary congestion became apparent at 15 wk (decompensated hypertrophy). In contrast, decompensation of cardiac function did not occur in W/W v mice; left ventricular performance was preserved throughout, and pulmonary congestion was not observed. Perivascular fibrosis and upregulation of mast cell chymase were all less apparent in W/W v mice. Treatment with tranilast, a mast cell–stabilizing agent, also prevented the evolu- tion from compensated hypertrophy to heart failure. These observations suggest that mast cells play a critical role in the progression of heart failure. Stabilization of mast cells may represent a new approach in the management of heart failure. Key words: heart failure • mast cells • left ventricular hypertrophy • pressure overload • chymase Introduction When the heart is exposed to pressure overload, cardiac hy- pertrophy develops to preserve its function by normalizing chamber wall stress (1). If mechanical overload persists, the hypertrophied heart dilates and its contractile function de- creases, resulting in congestive heart failure (1). The mech- anism of transition from compensated hypertrophy to heart failure has not been clarified (2). Mast cells are found in the human heart (3), and have been implicated in cardiovascular diseases (4, 5). They were increased in both hypertrophied (5) and failing hearts (6). However, their role in the pathophysiology of cardiac hypertrophy and failure is unclear. We have recently ob- served that mast cells cause apoptosis of cardiac myocytes and proliferation of nonmyocytes in vitro (7). As loss of cardiac myocytes and proliferation of nonmyocytes both result in cardiac dysfunction (1), we hypothesized that myocardial mast cells may be implicated in the progression of heart failure. This study was performed to examine whether mast cells play a role in the evolution from compensated hypertrophy to heart failure in a murine model of systolic pressure over- load, using W/c-kit mutant WBB6F1-W/W v mice, in which mast cells are nearly absent, and tranilast, a mast cell– stabilizing agent. Materials and Methods All experiments were performed in 9-wk-old male mice, ob- tained from Shizuoka Agricultural Cooperation Association, and treated in accordance with local institutional guidelines at all stages of the experiments. Experiment 1. Male W/W v mice ( n � 25), or their normal male littermates, WBB6F1- � / � (wild-type [WT]) mice ( n � 24), were exposed to 15 wk of pressure overload produced by banding of the abdominal aorta with minor modifications of a Address correspondence to Akira Matsumori, Department of Cardiovas- cular Medicine, Kyoto University Graduate School of Medicine, 54 Kawaracho Shogoin, Sakyo-ku, Kyoto 606-8397, Japan. Phone: 81-75- 751-3186; Fax: 81-75-751-6477; E-mail: [email protected] D ow nloaded from http://rupress.org/jem /article-pdf/195/3/375/1137663/jem 1953375.pdf by guest on 04 O ctober 2021 376 Mast Cells in Heart Failure method described previously (8). The mice were anesthetized by intraperitoneal injection of a mixture of ketamine, 100 mg/kg, and xylazine, 5 mg/kg. The abdominal aorta was banded at the suprarenal level with 5–0 silk suture material ligated around the vessel and a 26-gauge needle, following which the needle was withdrawn. In addition, 14 W/W v mice and 11 WT mice under- went identical surgical procedures, except for banding of the ab- dominal aorta (sham-operated controls). At 4 wk after operation, 10 W/W v mice and 10 WT mice were killed to examine the role of mast cells in compensated hypertrophy. Thereafter, the re- mainder of the mice were followed with serial echocardiography, and killed at 15 wk to examine the role of mast cells in congestive heart failure analyses. Mast Cell Reconstitution of W/W v Mice. Mast cell reconstitution of W/W v mice was performed as described previously (9). Bone marrow cells from femurs of male WT mice were cultured for 3 wk in WEHI-3 conditioned medium. To generate W/W v � MC mice, adoptive transfer of mast cells ( � 98% purity) into the hearts of W/W v mice was achieved by intravenous injection of 5 � 10 6 mast cells, 2 d before aortic banding. The mice were killed 15 wk after mast cell reconstitution and aortic banding. The density of cardiac mast cells was confirmed by staining with toluidine blue. Bone Marrow Reconstitution of W/W v Mice. The bone marrow reconstitution method has been described previously (10). Briefly, WT mice were killed by cervical dislocation, and the bone marrow was flushed with RPMI 1640 culture medium. Bone marrow cells (3 � 10 7 ) were injected intravenously into W/W v mice 2 d before aortic banding. W/W v mice with recon- stituted bone marrow were killed 15 wk later. Hematocrit was measured to confirm successful reconstitution. Morphologic and Echocardiographic Studies. After measurement of their body mass, the animals were anesthetized with ketamine (50 mg/kg) and xylazine (2.5 mg/kg). Transthoracic echocar- diography was performed with a cardiac ultrasound recorder (Toshiba Power Vision), using a 7.5-MHz transducer. After the acquisition of high quality two-dimensional images, M-mode im- ages of the left ventricle were recorded. Measurements of left ventricular enddiastolic (LVDd) and endsystolic (LVDs) internal dimensions were performed by the leading edge-to-leading edge convention adopted by the American Society of Echocar- diography. Percent fractional shortening (%FS) was calculated as %FS � ([LVDd � LVDs]/LVDd) � 100. Blood Pressure and Heart Rate Monitoring. The hemodynamic effects of aortic banding were monitored via the right carotid ar- tery exposed through a cervical incision and isolated by blunt dis- section as described by Rockman et al. (11). The lungs were dried for 120 min at 60 � C and weighed again. The lung water content (LW) was calculated as LW � lung weight (wet) � lung weight (dry). The pressure gradient across the aortic constriction was mea- sured directly at 4 wk after operation with a 24 gauge polyethyl- ene tube (TERUMO), inserted into the infrarenal abdominal aorta, then advanced through the stenosis to measure blood pres- sure at the suprarenal level. Pressure gradient was calculated as (systolic blood pressure at the suprarenal level) � (systolic blood pressure at the infrarenal level). Histological Analysis. We examined 15 banded W/W v mice, 14 banded WT mice, 10 sham-operated W/W v mice, and 9 sham-operated WT mice. The hearts were fixed with 10% for- malin for histological examinations. The fixed hearts were im- bedded in paraffin, sectioned in 2- � m thick slices, and stained with hematoxylin-eosin for overall morphology, or with Sirius red F3BA (0.1% solution in saturated aqueous picric acid) to al- low a clear discrimination between cardiac myocytes and collagen matrix (12). Changes in perivascular fibrosis were ascertained by relating the area of perivascular fibrosis to the total vessel area as described previously (13). For transmission electron microscopy, heart specimens were fixed with Karnovsky solution (3% glutaraldehyde and 1.6% paraformaldehyde in 0.1 mol/liter phosphate buffer [PB], pH 7.4) overnight at 4 � C and then were cut into 1-mm thick sections. They were postfixed in 1% osmium tetroxide in PB overnight at 4 � C, dehydrated in ethanol series, and embedded in Polybed (Polysciences Inc.). 70-nm thick ultrathin sections were stained with saturated uranyl acetate and lead citrate, and observed under a JEM-1200EX electron microscope (JEOL) at 100 kV. Measurement of Plasma Angiotensin II Level and Renin Activity. The abdomen of eight WBB6F1-W/W v mice and seven WT mice was opened under anesthesia with ketamine and xylazine when killed at 15 wk after aortic banding. Blood was rapidly ob- tained by puncture of the inferior vena cava, transferred to chilled tubes containing aprotinin (1,000 kallidinogenase inactivator units per milliliter) and Na 2 EDTA (1 mg/ml), and immediately centrifuged at 4 � C. Plasma samples were stored at � 80 � C until angiotensin II measurement by ELISA. Plasma renin activity (PRA) was determined using RENIN-RIABEAD (Dainabot). Quantitative Reverse Transcription PCR Analysis. We examined five mice of each groups. Total RNA was isolated from the left ventricle by the acid guanidinium thiocyanate-phenol-chloro- form method. Real-time quantitative PCR (TaqMan PCR) us- ing an ABI PRISM 7700 Sequence Detection System and Taq- Man PCR Core Reagent Kit (PerkinElmer) was performed ac- cording to the manufacturer’s protocol. 1 � l of the first strand cDNA was used in the following assay. The following forward (F) and reverse (R) oligonucleotides, and probes (P) were used for the quantification of mouse mast cell protease
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Answer To: Files/.DS_Store __MACOSX/Files/._.DS_Store Files/Article.pdf J. Exp. Med.  The Rockefeller...

Abirami answered on Oct 06 2021
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Immunology
Extensive Mast Cells in the heart can cause you Heart Failure
Mast cells are largely found in the abnormal
cardiac hypertrophy and dysfunctional conditions of the heart, yet their precise role in the pathophysiology of heart failure remains unknown. Thus, the finding of the functional role of mast cells in the heart failure could provide potential new approaches to the treatment and management of heart failure.
Cardiac hypertrophy is defined as enlargement and thickening of the heart muscles that lead to increased heart size and weight. This abnormality is usually caused due to the pressure overload in the heart chamber. Thereby, to compensate for the stress, the heart tries to normalize the stress by dilating and thickening the chamber wall. Continuous stress and dilation of the heart muscle often leads to loss of elasticity promoting decompensated hypertrophy. But the lack of elasticity in long run results in dysfunction and other contractile issues in the heart. The mechanism involved in the progression of these contractile issues from cardiac hypertrophy to heart failure has always been unclear and questionable. Thus, Hara et al., 2021 report the pathophysiology involved in the progression of cardiac hypertrophy to heart failure.
Mast cells are a specific type of white blood cells, that are found...
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