Interatrial septum pacing decreases atrial dyssynchrony on strain rate imaging compared with right atrial appendage pacing.

BACKGROUND: Interatrial septum pacing (IAS-P) decreases atrial conduction delay compared with right atrial appendage pacing (RAA-P). We evaluate the atrial contraction with strain rate of tissue Doppler imaging (TDI) during sinus activation or with IAS-P or RAA-P. METHODS: Fifty-two patients with permanent pacemaker for sinus node disease were enrolled in the study. Twenty-three subjects were with IAS-P and 29 with RAA-P. The time from end-diastole to peak end-diastolic strain rate was measured and corrected with RR interval on electrocardiogram. It was defined as the time from end-diastole to peak end-diastolic strain rate (TSRc), and the balance between maximum and minimum TSRc at three sites (ΔTSRc) was compared during sinus activation and with pacing rhythm in each group. RESULTS: There were no significant differences observed in general characteristics and standard echocardiographic parameters except the duration of pacing P wave between the two groups. The duration was significantly shorter in the IAS-P group compared with the RAA-P group (95 ± 34 vs 138 ± 41; P = 0.001). TSRc was significantly different between sinus activation and pacing rhythm (36.3 ± 35.7 vs 61.6 ± 36.3; P = 0.003) in the RAA-P group, whereas no significant differences were observed in the IAS-P group (25.4 ± 12.1 vs 27.7 ± 14.7; NS). During the follow-up (mean 2.4 ± 0.7 years), the incidence of paroxysmal atrial fibrillation (AF) conversion to permanent AF was not significantly different between the two groups. CONCLUSIONS: IAS-P decreased the contraction delay on atrial TDI compared to RAA-P; however, it did not contribute to the reduction of AF incidence in the present study.

The first clinical pilot study of intravenous adrenomedullin administration in patients with acute myocardial infarction.

Adrenomedullin (AM) is a 52-amino-acid vasodilator peptide that was originally isolated from human pheochromocytoma. In the previous experimental study with rat ischemia/reperfusion model, AM reduced infarct size and inhibited myocyte apoptosis. AM also suppressed the production of oxygen-free radicals. The present study was designed to evaluate the feasibility of intravenous administration of AM in patients with acute myocardial infarction. We studied 10 patients with first acute myocardial infarction [male to female ratio: 9 to 1, age: 65 ± 9 (mean ± SD) years, peak creatine phosphokinase level: 4215 ± 1933 (SD) U/L], who were hospitalized within 12 hours of symptom onset. Proceeding reperfusion therapy, AM infusion was initiated and continued at concentration of 0.0125-0.025 µg·kg·min for 12 hours. Follow-up coronary angiography and left ventriculography were performed at 3 months. Cardiac magnetic resonance was examined at 1 month and 3 months after AM therapy. During infusion of AM, hemodynamics kept stable except 2 patients. Wall motion index in the infarct area at 3 months was significantly improved compared with that at baseline, and infarct size evaluated by cardiac magnetic resonance was significantly decreased at 3 months. In conclusion, intravenous administration of AM, which possesses a variety of potential cardiovascular protective actions, can be adjunctive to percutaneous coronary intervention.

A case of Mikulicz's disease with Th2-biased cytokine profile: possible feature discriminable from Sjögren's syndrome.

This article concerns a male patient with Mikulicz's disease (MD) accompanied with marked elevation of serum immunoglobulin (Ig)G4 and IgE levels. His peripheral blood mononuclear cells (PBMC) showed markedly enhanced in vitro production of interleukin (IL)-4, IL-5, IL-13, but not interferon gamma (IFN-gamma) compared with patients with Sjögren's syndrome (SS) and healthy donors, suggesting distinct Th2 bias in this MD patient. Besides the prominent infiltration of IgG4-producing plasma cells, the enhanced expression of both CD40 and CD40 ligand (CD40L) were observed in the swollen salivary gland of the MD patient, suggesting enhanced signaling pathways for the induction of IgG4 and IgE switching. Possible differences between MD and SS in light of their underlying pathogenesis are discussed.

Abundant expression of tetraspanin CD9 in activated osteoclasts in ovariectomy-induced osteoporosis and in bone erosions of collagen-induced arthritis.

Tetraspanin CD9 has been shown to be critically involved in multinucleation and cell fusion during osteoclastogenesis, however, its in vivo pathophysiological role in bone-resorbing disorders such as osteoporosis and rheumatoid arthritis, has not been elucidated. To investigate the involvement of tetraspanin CD9 in bone destruction in such diseases, we examined the expression and distribution of tetraspanin CD9 using murine experimental models of osteoporosis and arthritis. In results, CD9 protein is abundantly expressed on the activated osteoclasts in the bone tissues whose trabeculae are severely reduced in ovariectomy-induced osteoporosis. The expression of CD9 is also detected at the sites of bone erosion in arthritic lesions of collagen-induced arthritis (CIA), where tartate-resistant acid phosphatase (TRAP) staining-positive activated osteoclasts are present. These data suggest that tetraspanin CD9 play important roles in bone destructions in osteoporosis and arthritis, and therefore, functional alterations of tetraspanin CD9 may have therapeutic potential in such bone-resorptive disorders.

Preparation of hydroxyapatite-nanocrystal-coated stainless steel, and its cell interaction.

Calcined nanocrystals of hydroxyapatite (HAp) having spherical or rod-shaped morphologies were coated through covalent linkage on a type 316L stainless steel substrate, which was chemically modified by the graft polymerization of gamma-methacryloxypropyl triethoxysilane (MPTS) at 70-110 degrees C. The grafting of poly(MPTS) on the substrate was confirmed by X-ray photoelectron spectroscopy (XPS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR). In order to coat the substrate with the HAp crystals through covalent linkage, the reactionbetween the alkoxysilyl groupsin the poly (MPTS) grafted on the substrate and the OH groups on the HAp crystals was conducted at 80 degrees C. The poly(MPTS)-grafted substrate was strongly coated with the HAp nanocrystals, although the HAp crystals adsorbed physically on the original substrate without poly(MPTS) grafting were removed by ultrasonic treatment. Human umbilical vein endothelial cells (HUVEC) adhered in larger numbers on the HAp-coated stainless steel substrate as compared with the original substrate after 24 h of initial incubation. The number of HUVEC adhered on the rod-shaped HAp-coated substrate was not significantly different from that on the spherical HAp-coated substrate under the present conditions.

Expression and function of transmembrane-4 superfamily (tetraspanin) proteins in osteoclasts: reciprocal roles of Tspan-5 and NET-6 during osteoclastogenesis.

BACKGROUND: Osteoclasts are bone-resorbing multinuclear polykaryons essential for bone remodeling, formed through cell fusion of mononuclear macrophage/monocyte lineage precursor cells upon stimulation by the RANK/RANKL system. Recent studies have revealed that a family of tetraspanin proteins, such as CD9, is critically involved in the cell fusion/polykaryon formation of these cell types. Until now, however, there is limited knowledge about the types of tetraspanins expressed in osteoclasts and their precursors. METHODS: The expression of different tetraspanin proteins in a monocyte/macrophage-lineage osteoclast precursor cell line, RAW264.7, was cyclopedically investigated using RT-PCR with specific primers and quantitative real-time RT-PCR. The function of two kinds of tetraspanins, Tspan-5 and NET-6, whose expression pattern was altered by RANKL stimulation, was examined by transfecting gene-specific short-interfering RNAs into these cell types. RESULTS: Of the 17 tetraspanins in mammalian hematopoietic cells, RAW264.7 cells express mRNA for 12 different kinds of tetraspanins, namely, CD9, CD37, CD53, CD63, CD81, CD82, CD151, NAG-2, NET-6, SAS, Tspan-3, and Tspan-5. Interestingly, during their maturation into osteoclasts upon RANKL stimulation, the transcript for Tspan-5 is up-regulated, whereas that for NET-6 is down-regulated. Targeted inhibition of Tspan-5 by using gene-specific RNA interference suppressed RANKL-induced cell fusion during osteoclastogenesis, whereas inhibition of NET-6 augmented the osteoclastogenesis itself. These results suggest that Tspan-5 and NET-6 have a reciprocal function during osteoclastogenesis, i.e., positive and negative regulation by Tspan-5 and NET-6, respectively. RANKL regulates osteoclastogenesis by altering the balances of these tetraspanin proteins. CONCLUSIONS: These data indicate that a diversity of tetraspanins is expressed in osteoclast precursors, and that cell fusion during osteoclastogenesis is regulated by cooperation of distinct tetraspanin family proteins such as Tspan-5 and NET-6. This study indicates that functional alterations of tetraspanin family proteins may have therapeutic potential in diseases where osteoclasts play a major role, such as rheumatoid arthritis and osteoporosis.

Different time course of changes in tricuspid regurgitant pressure gradient and pulmonary artery flow acceleration after pulmonary thromboendarterectomy: implications for discordant recovery of pulmonary artery pressure and compliance.

BACKGROUND: Pulmonary artery pressure (PAP) is reduced dramatically after pulmonary thromboendarterectomy in patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, it is unclear whether pulmonary artery compliance increases in conjunction with the reduction in PAP. Pulmonary artery compliance may affect right ventricular afterload and prognosis. METHODS AND RESULTS: In 33 patients with CTEPH (9 men, 22-76 years), changes in the tricuspid regurgitation pressure gradient (TRPG) and the acceleration time (ACT) of pulmonary artery flow (a surrogate parameter of pulmonary artery compliance) were examined before and after pulmonary thromboendarterectomy using echocardiography to clarify factors affecting the changes. At 6 months, both TRPG and ACT normalized (or=100 ms, respectively) in 25 patients (group A) but not in 8 (group B). In group B, there were 5 with normal TRPG and shortened ACT at 6 months that normalized at 17+/-3 months. Group A patients showed shorter disease period and shorter period without anticoagulation than group B patients (p=0.04, 0.02 respectively). All patients in group A had the proximal type, and 2 patients of group B had the distal type (p=0.05). Clinical improvement was more remarkable in group A. CONCLUSIONS: The recovery of PAP and the ACT of pulmonary artery flow was not always concordant after pulmonary thromboendarterectomy, suggesting a presence of a time lag in the recovery between pressure and compliance in some patients. A long period of CTEPH, a long period without anticoagulation and the distal embolism type may be predictive factors of an unfavorable operative result with reduced pulmonary artery compliance, and hence poor recovery of clinical performance.

RGS18 acts as a negative regulator of osteoclastogenesis by modulating the acid-sensing OGR1/NFAT signaling pathway.

UNLABELLED: We showed that RGS18, a myeloid lineage-specific RGS protein that is inhibited after activation of the RANK/RANKL system, is a negative regulator of osteoclastogenesis. RGS18 acts through an external acidosis-sensing osteoclastogenic mechanism through the OGR1/NFAT pathway. INTRODUCTION: Osteoclasts are bone-resorbing multinuclear giant cells that are differentiated from mononuclear macrophage/monocyte lineage precursors stimulated by the RANK/RANKL system. The regulators of G-protein signaling (RGS) family is a diverse group of proteins that accelerate intrinsic GTP hydrolysis on heterotrimeric G-protein alpha subunits and play crucial roles in physiological regulation of G-protein-mediated cell signaling in various tissues and organs. We examined the expression and function of RGS18, a myeloid lineage-specific RGS protein, during osteoclastogenesis. MATERIALS AND METHODS: A macrophage/monocyte lineage cell line, RAW264.7, and primary osteoclast precursor monocytes derived from mouse bone marrow cultured with macrophage-colony stimulating factor (M-CSF) (bone marrow-derived monocytes [BMMs]) were used in this study. Both cell types differentiate into osteoclast-like cells on activation by RANKL. Expression of different RGS proteins, including RGS18, was assessed by gene-specific RT-PCR. The subcellular distribution of RGS18 on native osteoclasts in bone tissues, as well as in RAW264.7 cells, was examined by immunohistochemistry using a specific polyclonal antibody. Short interfering RNA against RGS18 was used to inhibit the function endogenous RGS18 in these cell types. Activation of NFATc1, an osteoclastogenic transcription factor, on external acidosis was assessed by visualizing the nuclear localization of NFATc1 visualized with anti-NFATc1 antibody. RESULTS: RAW264.7 and BMM cells both expressed mRNA for 10 different mammalian RGS proteins, including RGS18. Expression of RGS18 is significantly inhibited by RANKL both cell types, and inhibition of RGS18 function using RNA interference prominently enhanced osteoclastogenesis on stimulation with RANKL. The effect of RGS18 inhibition was reversed by blocking of proton-sensing OGR1 signaling, and overexpression of exogenous RGS18 inhibited extracellular acidosis-mediated NFATc1 activation. Immunohistochemical studies of mouse bone tissues revealed expression of RGS18 in osteoclasts in vivo. CONCLUSIONS: RGS18 acts as a negative regulator of the acidosis-induced osteoclastogenic OGR1/NFAT signaling pathway, and RANKL stimulates osteoclastogenesis by inhibiting expression of RGS18. Therefore, the results suggest a novel control mechanism of osteoclastogenesis by RGS proteins.

Increase in cell adhesiveness on a poly(ethylene terephthalate) fabric by sintered hydroxyapatite nanocrystal coating in the development of an artificial blood vessel.

Nano-scaled sintered hydroxyapatite (HAp) crystals were covalently linked onto a poly(ethylene terephthalate) (PET) fabric substrate chemically modified by graft polymerization with gamma-methacryloxypropyl triethoxysilane (MPTS) for development of an artificial blood vessel. The weight gain of graft polymerization with poly(MPTS) on PET in benzyl alcohol containing H2O2 as an initiator increased as increasing the reaction time and finally reached a plateau value of about 3.5 wt%. The surface characterization of surface modification with poly(MPTS)-grafting was conducted by x-ray photoelectron spectroscopy. HAp nanocrystals of approximately 50 nm in diameter, monodispersed in pure ethanol, were coupled with alkoxysilyl groups of the poly(MPTS)-grafted PET substrate. The HAp nanocrystals were uniformly and strongly coated on the surface of the PET fabrics, although HAp particles adsorbed physically on the original PET without poly(MPTS) grafting were almost removed by ultrasonic wave treatment. More human umbilical vein endothelial cells adhered to the HAp/PET composite fabric compared with original PET after only 4 hours of initial incubation, and the same was observed on the collagen-coated PET. The coating of sintered HAp nanocrystals imparted bioactivity to the polyester substrate, which is a widely used biomedical polymer, without a coating of adhesion proteins derived from animals, such as collagen or gelatin. A prototype of an artificial blood vessel was finally fabricated by use of HAp/PET composite.

RANKL-induced expression of tetraspanin CD9 in lipid raft membrane microdomain is essential for cell fusion during osteoclastogenesis.

UNLABELLED: We showed that CD9, a member of tetraspanin superfamily proteins, is expressed in a specific membrane microdomain, called "lipid raft," and is crucial for cell fusion during osteoclastogenesis after activation of the RANK/RANKL system. INTRODUCTION: Osteoclasts are bone-resorbing multinuclear polykaryons that are essential for bone remodeling and are formed through cell fusion of mononuclear macrophage/monocyte lineage precursors. Although osteoclastogenesis has been shown to be critically regulated by the RANK/RANKL system, the mechanism how precursor cells fuse with each other remains unclear. We examined the function of CD9, a member of tetraspanin superfamily, which has previously been shown to form macromolecular membrane microdomains and to regulate cell-cell fusion in various cell types. MATERIALS AND METHODS: We used RAW264.7, a macrophage/monocyte lineage cell line, which can differentiate into osteoclast-like polykaryons on the application of RANKL. Expression and distribution of CD9 was assessed by Western blotting, fluorescence-assorted cell sorting (FACS) and immunohistochemistry with light and electron microscopy. A specific neutralizing antibody and RNA interference were used to inhibit the function of CD9, and green fluorescent protein (GFP)-CD9 was exogenously expressed to enhance the effect of CD9. The distribution of CD9 in lipid microdomain was examined by biochemical (sucrose density gradient) isolation and imaging technique. RESULTS: CD9 is expressed on cell surfaces of RAW264.7, which is enhanced by RANKL. Targeted inhibition of CD9 decreases the number of osteoclast-like cells. On the other hand, overexpression of CD9 promotes spontaneous cell fusion even in the absence of RANKL. CD9 is localized in detergent-insoluble "lipid raft" microdomain in RANKL stimulation, and disruption of lipid rafts markedly reduces the formation of osteoclast-like polykaryons. Immunohistochemical studies of bone tissues revealed the expression of CD9 in osteoclasts in vivo. CONCLUSIONS: These data suggest that function of tetraspanin CD9 and its expression in lipid rafts are crucial for cell fusion during osteoclastogenesis.

Increased gene expression of collagen Types I and III is inhibited by beta-receptor blockade in patients with dilated cardiomyopathy.

AIMS: To elucidate the cellular mechanisms of cardioprotection of beta-blockers in patients with heart failure, we investigated the effects of beta-blockers on collagen synthesis in patients with dilated cardiomyopathy (DCM). METHODS AND RESULTS: We examined the gene expression before and 4 months after the administration of a beta-blocker in 17 DCM patients. The messenger ribonucleic acid expression of collagen Types I and III (Col I and III) and transforming growth factor-beta(1) (TGF-beta(1)) of right ventricular tissues obtained by the endomyocardial biopsy were assessed by quantitative reverse transcriptase-polymerase chain reaction. Cardiac sympathetic nerve activity was assessed by the washout rate (WR) of (123)I-metaiodobenzylguanidine from the heart. Left ventricular ejection fraction (21 +/- 7 vs. 35 +/- 9%) and WR (53+/-14 vs. 42 +/- 13%) improved significantly. Before the beta-blocker treatment, the expressions of both Col I (r = 0.560, P = 0.041) and Col III (r = 0.630, P = 0.008) genes were correlated with WR. The expression levels of both Col I (1.08 +/- 0.72 vs. 0.65 +/- 0.26, P = 0.024) and Col III (2.06 +/- 1.81 vs. 1.05 +/- 0.74, P = 0.018) were reduced by a beta-blocker. Changes in TGF-beta(1) correlated with those in WR (r = 0.606, P = 0.002). CONCLUSION: beta-Blockers are considered to inhibit the expression of collagen-related genes in DCM, which seems to be mediated by TGF-beta(1).

Treatment of cachexia with ghrelin in patients with COPD.

STUDY OBJECTIVES: Ghrelin is a novel growth hormone (GH)-releasing peptide that also induces a positive energy balance by decreasing fat utility and stimulating feeding through GH-independent mechanisms. We investigated whether ghrelin improves cachexia and functional capacity in patients with COPD. METHODS: This is an open-label pilot study. Human ghrelin (2 microg/kg bid) was IV administered to seven cachectic patients with COPD for 3 weeks. Food intake, body composition, muscle strength, exercise capacity, pulmonary function, and sympathetic nerve activity were examined before and after ghrelin therapy. RESULTS: A single administration of ghrelin markedly increased serum GH (21-fold). Three-week treatment with ghrelin resulted in a significant increase in mean (+/- SEM) body weight (49.3 +/- 3.6 to 50.3 +/- 3.8 kg; p < 0.05). Food intake was significantly increased during ghrelin therapy. Ghrelin increased lean body mass and peripheral and respiratory muscle strength. Ghrelin significantly increased Karnofsky performance status score and the distance walked in 6 min (370 +/- 30 to 432 +/- 35 m; p < 0.05), although it did not significantly alter pulmonary function. Ghrelin attenuated the exaggerated sympathetic nerve activity, as indicated by a marked decrease in plasma norepinephrine level (889 +/- 123 to 597 +/- 116 pg/mL; p < 0.05). CONCLUSIONS: These preliminary results suggest that repeated administration of ghrelin improves body composition, muscle wasting, functional capacity, and sympathetic augmentation in cachectic patients with COPD.

Transplantation of mesenchymal stem cells improves cardiac function in a rat model of dilated cardiomyopathy.

BACKGROUND: Pluripotent mesenchymal stem cells (MSCs) differentiate into a variety of cells, including cardiomyocytes and vascular endothelial cells. However, little information is available about the therapeutic potency of MSC transplantation in cases of dilated cardiomyopathy (DCM), an important cause of heart failure. METHODS AND RESULTS: We investigated whether transplanted MSCs induce myogenesis and angiogenesis and improve cardiac function in a rat model of DCM. MSCs were isolated from bone marrow aspirates of isogenic adult rats and expanded ex vivo. Cultured MSCs secreted large amounts of the angiogenic, antiapoptotic, and mitogenic factors vascular endothelial growth factor, hepatocyte growth factor, adrenomedullin, and insulin-like growth factor-1. Five weeks after immunization, MSCs or vehicle was injected into the myocardium. Some engrafted MSCs were positive for the cardiac markers desmin, cardiac troponin T, and connexin-43, whereas others formed vascular structures and were positive for von Willebrand factor or smooth muscle actin. Compared with vehicle injection, MSC transplantation significantly increased capillary density and decreased the collagen volume fraction in the myocardium, resulting in decreased left ventricular end-diastolic pressure (11+/-1 versus 16+/-1 mm Hg, P<0.05) and increased left ventricular maximum dP/dt (6767+/-323 versus 5138+/-280 mm Hg/s, P<0.05). CONCLUSIONS: MSC transplantation improved cardiac function in a rat model of DCM, possibly through induction of myogenesis and angiogenesis, as well as by inhibition of myocardial fibrosis. The beneficial effects of MSCs might be mediated not only by their differentiation into cardiomyocytes and vascular cells but also by their ability to supply large amounts of angiogenic, antiapoptotic, and mitogenic factors.

Adrenomedullin enhances therapeutic potency of mesenchymal stem cells after experimental stroke in rats.

BACKGROUND AND PURPOSE: Adrenomedullin (AM) induces angiogenesis and inhibits cell apoptosis through the phosphatidylinositol 3-kinase/Akt pathway. Transplantation of mesenchymal stem cells (MSCs) has been shown to improve neurological deficits after stroke in rats. We investigated whether AM enhances the therapeutic potency of MSC transplantation. METHODS: Male Lewis rats (n=100) were subjected to 2-hour middle cerebral artery occlusion. Immediately after reperfusion, rats were assigned randomly to receive intravenous transplantation of MSCs plus subcutaneous infusion of AM for 7 days (MSC+AM group), AM infusion alone (AM group), MSC transplantation alone (MSC group), or vehicle infusion (control group). Neurological and immunohistological assessments were performed to examine the effects of these treatments. RESULTS: Some engrafted MSCs were positive for neuronal and endothelial cell markers, although the number of differentiated MSCs did not differ significantly between the MSC and MSC+AM groups. The neurological score significantly improved in the MSC, AM, and MSC+AM groups compared with the control group. Importantly, improvement in the MSC+AM group was significantly greater than that in the MSC and AM groups. There was marked induction of angiogenesis in the ischemic penumbra in the MSC+AM group, followed by the AM, MSC, and control groups. AM infusion significantly inhibited apoptosis of transplanted MSCs. As a result, the number of engrafted MSCs in the MSC+AM group was significantly higher than that in the MSC group. CONCLUSIONS: AM enhanced the therapeutic potency of MSCs, including neurological improvement, possibly through inhibition of MSC apoptosis and induction of angiogenesis.

Adrenomedullin enhances angiogenic potency of bone marrow transplantation in a rat model of hindlimb ischemia.

BACKGROUND: Previous studies have shown that adrenomedullin (AM) inhibits vascular endothelial cell apoptosis and induces angiogenesis. We investigated whether AM enhances bone marrow cell-induced angiogenesis. METHODS AND RESULTS: Immediately after hindlimb ischemia was created, rats were randomized to receive AM infusion plus bone marrow-derived mononuclear cell (MNC) transplantation (AM+MNC group), AM infusion alone (AM group), MNC transplantation alone (MNC group), or vehicle infusion (control group). The laser Doppler perfusion index was significantly higher in the AM and MNC groups than in the control group (0.74+/-0.11 and 0.69+/-0.07 versus 0.59+/-0.07, respectively, P<0.01), which suggests the angiogenic potency of AM and MNC. Importantly, improvement in blood perfusion was marked in the AM+MNC group (0.84+/-0.08). Capillary density was highest in the AM+MNC group, followed by the AM and MNC groups. In vitro, AM inhibited MNC apoptosis, promoted MNC adhesiveness to a human umbilical vein endothelial cell monolayer, and increased the number of MNC-derived endothelial progenitor cells. In vivo, AM administration not only enhanced the differentiation of MNC into endothelial cells but also produced mature vessels that included smooth muscle cells. CONCLUSIONS: A combination of AM infusion and MNC transplantation caused significantly greater improvement in hindlimb ischemia than MNC transplantation alone. This effect may be mediated in part by the angiogenic potency of AM itself and the beneficial effects of AM on the survival, adhesion, and differentiation of transplanted MNCs.

Effects of ghrelin administration on left ventricular function, exercise capacity, and muscle wasting in patients with chronic heart failure.

BACKGROUND: Ghrelin is a novel growth hormone-releasing peptide that also induces vasodilation, inhibits sympathetic nerve activity, and stimulates feeding through growth hormone-independent mechanisms. We investigated the effects of ghrelin on left ventricular (LV) function, exercise capacity, and muscle wasting in patients with chronic heart failure (CHF). METHODS AND RESULTS: Human synthetic ghrelin (2 microg/kg twice a day) was intravenously administered to 10 patients with CHF for 3 weeks. Echocardiography, cardiopulmonary exercise testing, dual x-ray absorptiometry, and blood sampling were performed before and after ghrelin therapy. A single administration of ghrelin elicited a marked increase in serum GH (25-fold). Three-week administration of ghrelin resulted in a significant decrease in plasma norepinephrine (1132+/-188 to 655+/-134 pg/mL; P<0.001). Ghrelin increased LV ejection fraction (27+/-2% to 31+/-2%; P<0.05) in association with an increase in LV mass and a decrease in LV end-systolic volume. Treatment with ghrelin increased peak workload and peak oxygen consumption during exercise. Ghrelin improved muscle wasting, as indicated by increases in muscle strength and lean body mass. These parameters remained unchanged in 8 patients with CHF who did not receive ghrelin therapy. CONCLUSIONS: These preliminary results suggest that repeated administration of ghrelin improves LV function, exercise capacity, and muscle wasting in patients with CHF.

A novel application of myocardial contrast echocardiography to evaluate angiogenesis by autologous bone marrow cell transplantation in chronic ischemic pig model.

OBJECTIVES: We investigated the feasibility of myocardial contrast echocardiography (MCE) to evaluate regional perfusion after bone marrow cell transplantation. BACKGROUND: The myocardial microvessels improved by cell transplantation are too small to visualize with conventional angiography. METHODS: Fourteen mini-pigs from the Nippon Institute for Biological Science were used. The proximal left anterior descending coronary artery was ligated. One month later, nine pigs survived. Six pigs received autologous cell transplantation into the left ventricular anterior wall: bone marrow mononuclear cells (BMMNCs) (n = 3) and bone marrow stromal cells (BMSCs) (n = 3). The other three pigs received saline (control group, n = 3). The pigs were sacrificed one month later. Myocardial contrast intensity (MCI) with a contrast agent was measured using the SONOS 5500 system (Philips). Capillary density (CD) and MCI were measured at four areas: anteroseptum (nontransplanted infarct area), anterior wall (transplanted infarct area), septum (border zone), and lateral wall (normal). We compared the anteroseptum with the anterior wall by MCI and CD. RESULTS: In the BMMNC and BMSC subsets, the CD of the anterior wall was higher than that of the anteroseptum (p < 0.001). There was a linear relation between MCI and CD (acoustic unit [AU2] = 0.234 CD + 0.010, r = 0.92, p < 0.001). At one month after cell transplantation, MCI of the anterior wall increased in the BMMNC and BMSC subsets (p < 0.05), although it did not change in the control group. The ratio of wall thickness (systole/diastole) in the transplanted infarct area was larger than that in the nontransplanted infarct area (p < 0.01). CONCLUSIONS: Myocardial contrast echocardiography is useful to evaluate regional perfusion, which was enhanced by bone marrow cell transplantation.

The role of a common TNNT2 polymorphism in cardiac hypertrophy.

We found a five-basepair insertion/deletion polymorphism in intron 3 of TNNT2, one of the genes responsible for hypertrophic cardiomyopathy. These five bases may be part of an intronic polypyrimidine tract sequence that may affect splicing. The purpose of the study was to examine the association of the polymorphism with cardiac hypertrophy. The study population consisted of 151 subjects with prominent concentric left ventricular hypertrophy, and 987 healthy subjects recruited from medical checkups (control population). The deletion/deletion genotype tended to be associated with a larger left ventricular mass/height ratio in the HCM population ( p<0.0001). Multiple regression analyses indicated that the left ventricular mass/height ratio was determined ( p<0.0001, R=0.738) by the TNNT2 genotype. Moreover, the frequency of the deletion allele was significantly higher in the hypertrophy population than in the control population ( p<0.0001). In vitro expression study revealed the deletion allele significantly affected the mRNA expression pattern by skipping exon 4 during splicing. In conclusion, TNNT2 deletion allele could be associated with a predisposition to prominent left ventricular hypertrophy.

Effects of adrenomedullin inhalation on hemodynamics and exercise capacity in patients with idiopathic pulmonary arterial hypertension.

BACKGROUND: Adrenomedullin (AM) is a potent pulmonary vasodilator peptide. However, whether intratracheal delivery of aerosolized AM has beneficial effects in patients with idiopathic pulmonary arterial hypertension remains unknown. Accordingly, we investigated the effects of AM inhalation on pulmonary hemodynamics and exercise capacity in patients with idiopathic pulmonary arterial hypertension. METHODS AND RESULTS: Acute hemodynamic responses to inhalation of aerosolized AM (10 microg/kg body wt) were examined in 11 patients with idiopathic pulmonary arterial hypertension during cardiac catheterization. Cardiopulmonary exercise testing was performed immediately after inhalation of aerosolized AM or placebo. The work rate was increased by 15 W/min until the symptom-limited maximum, with breath-by-breath gas analysis. Inhalation of AM produced a 13% decrease in mean pulmonary arterial pressure (54+/-3 to 47+/-3 mm Hg, P<0.05) and a 22% decrease in pulmonary vascular resistance (12.6+/-1.5 to 9.8+/-1.3 Wood units, P<0.05). However, neither systemic arterial pressure nor heart rate was altered. Inhalation of AM significantly increased peak oxygen consumption during exercise (peak o(2), 14.6+/-0.6 to 15.7+/-0.6 mL. kg(-1). min(-1), P<0.05) and the ratio of change in oxygen uptake to that in work rate (Deltao(2)/DeltaW ratio, 6.3+/-0.4 to 7.0+/-0.5 mL. min(-1). W(-1), P<0.05). These parameters remained unchanged during placebo inhalation. CONCLUSIONS: Inhalation of AM may have beneficial effects on pulmonary hemodynamics and exercise capacity in patients with idiopathic pulmonary arterial hypertension.

Repeated inhalation of adrenomedullin ameliorates pulmonary hypertension and survival in monocrotaline rats.

Adrenomedullin (AM) is a potent vasodilator peptide. We investigated whether inhalation of aerosolized AM ameliorates monocrotaline (MCT)-induced pulmonary hypertension in rats. Male Wistar rats given MCT (MCT rats) were assigned to receive repeated inhalation of AM (n = 8) or 0.9% saline (n = 8). AM (5 mug/kg) or saline was inhaled as an aerosol using an ultrasonic nebulizer for 30 min four times a day. After 3 wk of inhalation therapy, mean pulmonary arterial pressure and total pulmonary resistance were markedly lower in rats treated with AM than in those given saline [mean pulmonary arterial pressure: 22 +/- 2 vs. 35 +/- 1 mmHg (-37%); total pulmonary resistance: 0.048 +/- 0.004 vs. 0.104 +/- 0.006 mmHg.ml(-1).min(-1).kg(-1) (-54%), both P < 0.01]. Neither systemic arterial pressure nor heart rate was altered. Inhalation of AM significantly attenuated the increase in medial wall thickness of peripheral pulmonary arteries in MCT rats. Kaplan-Meier survival curves demonstrated that MCT rats treated with aerosolized AM had a significantly higher survival rate than those given saline (70% vs. 10% 6-wk survival, log-rank test, P < 0.01). In conclusion, repeated inhalation of AM inhibited MCT-induced pulmonary hypertension without systemic hypotension and thereby improved survival in MCT rats.