Arginine-specific gingipains from Porphyromonas gingivalis deprive protective functions of secretory leucocyte protease inhibitor in periodontal tissue

Chronic periodontitis is correlated with Porphyromonas gingivalis infection. In this study, we found that the expression of secretory leucocyte protease inhibitor (SLPI), an endogenous inhibitor for neutrophil-derived proteases, was reduced in gingival tissues with chronic periodontitis associated with P. gingivalis infection. The addition of vesicles of P. gingivalis decreased the amount of SLPI in the media of primary human gingival keratinocytes compared to untreated cultures. We therefore investigated how arginine-specific gingipains (Rgps) affect the functions of SLPI, because Rgps are the major virulence factors in the vesicles and cleave a wide range of in-host proteins. We found that Rgps digest SLPI in vitro, suppressing the release of SLPI. Rgps proteolysis of SLPI disrupted SLPI functions, which normally suppresses neutrophil elastase and neutralizes pro-inflammatory effects of bacterial cell wall compounds in cultured human gingival fibroblasts. The protease inhibitory action of SLPI was not exerted towards Rgps. These results suggest that Rgps reduce the protective effects of SLPI on neutrophil proteases and bacterial proinflammatory compounds, by which disease in gingival tissue may be accelerated at the sites with P. gingivalis infection.

Adiponectin produced in coronary circulation regulates coronary flow reserve in nondiabetic patients with angiographically normal coronary arteries

BACKGROUND

Epicardial adipose tissue expresses adiponectin protein, and its expression is significantly lower in patients with severe coronary artery disease (CAD) than in those without CAD. Transcoronary adiponectin levels are significantly decreased in nondiabetic but not in diabetic patients with CAD. Adiponectin is also an important adipocytokine that is linked to insulin resistance and reduces coronary microvascular function.

HYPOTHESIS

Adiponectin may play a significant role in the localized coronary circulation. The present study examines the local dynamics of adiponectin in the coronary circulation in nondiabetic individuals with normal coronary arteries and the relationship between adiponectin and coronary microvasculature function.

METHODS

We examined 22 consecutive nondiabetic patients whose coronary arteries were angiographically normal. Plasma levels of adiponectin were measured in blood samples that were simultaneously collected from the orifice of the left coronary artery (LCA) and the great cardiac vein (GCV). To evaluate the function of the coronary microcirculation, we measured coronary flow velocity at maximal hyperemia using a Doppler wire. Coronary flow reserve (CFR) was obtained from the ratio of hyperemia to the baseline coronary flow velocity.

RESULTS

Plasma adiponectin levels in the GCV (median 6.95 microg/ml) were significantly higher than those in the LCA (median 6.60 microg/ml, p < 0.0005). The difference in plasma adiponectin levels between GCV and LCA significantly correlated with CFR (R = 0.451, p < 0.05).

CONCLUSIONS

Adiponectin is locally produced in the coronary circulation. This protein may participate in modulating the coronary circulation of nondiabetic patients with angiographically normal coronary arteries.

Soluble guanylate cyclase stimulation on cardiovascular remodeling in angiotensin II-induced hypertensive rats

It is unknown whether long-term pharmacological stimulation of soluble guanylate cyclase (sGC), elevating intracellular cGMP levels, has a beneficial effect on hypertension. The purpose of this study is to investigate the effects of BAY41-2272, an orally available sGC stimulator, on cardiovascular remodeling in hypertensive rats. Eight-week-old male Wistar rats with hypertension induced by angiotensin II infused subcutaneously at 250 ng/kg per minute were treated orally with a low ([L] 2 mg/kg per day) or high ([H] 10 mg/kg per day) dose of BAY41-2272 for 14 days. BAY41-2272-H partially suppressed the rise in blood pressure and reduced the heart weight (4.20+/-0.34 versus 3.68+/-0.20 mg/g; P<0.01), whereas BAY41-2272-L had no effect. However, both doses decreased the angiotensin II-induced left ventricular accumulation of collagen in the perivascular area (L, -20%, P<0.05; H, -30%, P<0.01) and myocardial interstitium (L, -21%, P<0.05; H, -38%, P<0.01), reducing the number of activated fibroblasts surrounding coronary arteries (L, -74%; H, -79%; P<0.05). BAY41-2272 downregulated the angiotensin II-induced left ventricular gene expression of type 1 collagen (L, -41%, P<0.05; H, -49%, P<0.01) and transforming growth factor-beta1 (L, -49%, P<0.05; H, -65%, P<0.01). cGMP levels were elevated by BAY41-2272 not only in the left ventricle, but also in cultured cardiac fibroblasts, resulting in reduced thymidine incorporation into the cells. Thus, stimulation of sGC by BAY41-2272 attenuates fibrosis of the left ventricle in rats with angiotensin II-induced hypertension partly in a pressure-independent manner, suggesting an important role for sGC generating cGMP in inhibiting cardiovascular remodeling.

Accuracy of economic studies on surgical site infection

Estimating the cost of hospital infection has become a matter of increasing interest in terms of health economics. This study aimed to assess the accuracy of economic studies on hospital infections, using surgical site infection (SSI) as an example. A search was performed for original articles reporting the cost of SSI, published in the English language between 1996 and 2005. For the critical review, the period of cost tracking, classification of costs and cost counting methods were noted. Fifteen articles met the inclusion criteria. The costs of SSI vary according to surgical procedures, country, publication year, study design and accounting method. Only two studies estimated the additional cost of SSI after discharge. All 15 studies included healthcare costs and none measured patient/family resources. In 10 studies, the costs were calculated based on accounting. Three studies used estimated costs from the ratio of costs to charges and two studies used charge data in place of cost data. It will become increasingly important for future studies to perform multi-centre prospective surveys, establish a standard method for cost accounting, include the cost of healthcare services following hospitalization and consider the morbidity cost to patients themselves from a societal perspective.

Factor XI contributes to thrombus propagation on injured neointima of the rabbit iliac artery

BACKGROUND

Thrombus formation through the activation of tissue factor (TF) and factor (F) XI is a critical event in the onset of cardiovascular disease. TF expressed in atherosclerotic plaques and circulating blood is an important determinant of thrombogenicity that contributes to fibrin-rich thrombus formation after plaque disruption. However, the contribution of FXI to thrombus formation on disrupted plaques remains unclear.

METHODS

A mouse monoclonal antibody against FXI and activated FXI (FXIa) (XI-5108) was generated by immunization with activated human FXI. Prothrombin time (PT), activated partial thromboplastin time (APTT), bleeding time, and ex vivo platelet aggregation in rabbits were measured before and after an intravenous bolus injection of XI-5108. We investigated the role of FXI upon arterial thrombus growth in the rabbit iliac artery in the presence of repeated balloon injury.

RESULTS

The XI-5108 antibody reacted to the light chain of human and rabbit FXI/FXIa, and inhibited FXIa-initiated FXa and FXIa generation. Fibrin-rich thrombi developed on the injured neointima that was obviously immunopositive for glycoprotein IIb-IIIa, fibrin, TF, and FXI. Intravenous administration of XI-5108 (3.0 mg kg(-1)) remarkably reduced thrombus growth, and the APTT was significantly prolonged. However, PT, bleeding time and platelet aggregation were not affected.

CONCLUSIONS

These results indicate that plasma FXI plays a potent role in thrombus growth on the injured neointima. Inhibition of plasma FXI activity might help to reduce thrombus growth on ruptured plaques without prolonging bleeding time.

Different inflammatory response and oxidative stress in neointimal hyperplasia after balloon angioplasty and stent implantation in cholesterol-fed rabbits

Inflammatory responses appear to play an important role in the occurrence of restenosis following coronary intervention. However, the contribution of C-reactive protein (CRP) and oxidative stress to restenosis after balloon angioplasty and stent implantation remains unclear. The aim of this study was to examine this issue using hyperlipidemic rabbits. Rabbits were divided into two groups; they were fed with a 0.5% cholesterol diet and with a mixed 0.5% cholesterol and 0.5% probucol diet. Each group of rabbits underwent balloon injury and stent implantation in right and left iliac arteries, respectively. Eight weeks after the intervention, we examined luminal stenosis, neointimal hyperplasia, immunoreactivity for macrophage, CRP and oxidized phosphatidylcholine (oxPC), and also the expression of CRP mRNA. The degrees of neointimal hyperplasia and immunopositive areas (%) for macrophage, CRP, and oxPC in the neointima were significantly higher after stent implantation than after balloon injury, but CRP mRNA was undetectable in either artery. Anti-oxidant probucol reduced angiographic stenosis, neointimal hyperplasia, and macrophage- and oxPC-positive areas much more significantly after stenting. The results demonstrate that the inflammatory response to the development of neointimal hyperplasia differs after balloon injury and stent implantation and that CRP deposition and oxidative stress might be involved more significantly in neointimal development after stent implantation.

Allogeneic stem cell transplantation in children with acute lymphoblastic leukemia after isolated central nervous system relapse: our experiences and review of the literature

The prognosis of patients with acute lymphoblastic leukemia (ALL) and central nervous system (CNS) relapse has historically been very poor. Although chemo-radiotherapy has improved outcomes, some patients still have a poor prognosis after CNS relapse. Therefore, allogeneic hematopoietic stem cell transplantation (allo-SCT) has recently become an option for treatment of CNS leukemia; however, information, particularly on the long-term outcome of transplant recipients, is limited. We performed allo-SCT in eight pediatric patients with ALL (n=7) or T-cell type non-Hodgkin's lymphoma (n=1), who had isolated CNS relapse. All patients survived for a median of 70.5 (range, 13-153) months after SCT. Sequelae developed late in some patients: mental retardation (IQ=47) in one patient, severe alopecia in two patients, limited chronic graft-versus-host-disease in three patients, and amenorrhea and/or hypothyroidism in three patients. Except for a pre-school child with post transplant CNS relapse, six out of seven patients show normal school/social performance. Our results clearly indicate a high cure rate of isolated CNS relapse by allo-SCT in pediatric lymphoid malignancies; however, there needs to be further studies to determine which are the appropriate candidates for transplantation and what is the best transplant regimen to achieve high cure rate and maintain good quality of life.

Adrenomedullin in mast cells of abdominal aortic aneurysm

OBJECTIVES

Produced by vascular walls, adrenomedullin (AM) exerts antifibrotic actions in the process of cardiovascular remodeling. The purpose of this study was to examine the pathophysiological role of AM in the development of human abdominal aortic aneurysm (AAA).

METHODS AND RESULTS

Immunohistochemical analyses revealed that vascular smooth muscle cells in the media were positive for AM in the early stage of atherosclerotic aorta. Intense immunoreactivity was observed in mast cells of the outer media and adventitia of AAA, and the number of mast cells was greater (p < 0.01) in AAA than in atherosclerotic aorta without any aneurysmal change. To determine the role of AM in mast cells, we examined cultured human mast cell leukemia line-1 (HMC-1) and fibroblasts isolated from AAA patients. Cultured HMC-1 cells were found to express preproAM gene and release AM peptide into the cultured media. When assessed by collagenase-sensitive [3H]proline incorporation and procollagen type I C-peptide secretion, collagen synthesis in co-culture of HMC-1 and the fibroblasts was reduced by 10(-6) mol/L synthetic AM, while conversely, it increased following blockade of the action of endogenous AM with 10 microg/mL anti-AM monoclonal antibody.

CONCLUSION

The present study suggests an anti-fibrotic role for AM released from mast cells, providing new insight into the biological actions of mast cell-derived AM in the development of AAA.

Increased expression of interleukin-10 in unstable plaque obtained by directional coronary atherectomy

AIMS

The present study investigates the expression and localization of interleukin (IL)-10, an important anti-inflammatory cytokine, in atherectomy specimens from patients with stable and unstable angina.

METHODS AND RESULTS

Twenty-two patients with stable angina and 21 with unstable angina who underwent directional coronary atherectomy for de novo lesions were studied. The atherectomy specimens were morphologically assessed and immunohistochemically stained with antibodies for IL-10, macrophages, smooth muscle cells, and endothelial cells. The localization and immunopositive areas were evaluated using an image analysing system. Immunoreactivity for IL-10 was detected in coronary plaques, especially in macrophages. Immunopositive areas of macrophages and IL-10, as well as the incidence of thrombus formation, were significantly greater in specimens from patients with unstable angina than in those from patients with stable angina (macrophages, P<0.001; IL-10, P<0.05; thrombus formation, P<0.05; respectively). Even after adjustment, IL-10 expression and the incidence of thrombus formation were significantly greater in the unstable angina group (P<0.05, each). The immunoreactivities for smooth muscle cells and endothelial cells did not differ between the two groups.

CONCLUSION

IL-10 was more frequently expressed in specimens from patients with unstable angina. This finding might contribute to a better understanding of plaque instability.

Detection of von Willebrand factor and tissue factor in platelets-fibrin rich coronary thrombi in acute myocardial infarction

The rapid closure of coronary arteries due to occlusive thrombi is the major cause of acute myocardial infarction. However, the mechanisms of coronary thrombus formation have not been elucidated. We immunohistochemically assessed the localizations and their changes over time of glycoprotein IIb/IIIa, fibrin, von Willebrand factor (vWF), and tissue factor (TF), after the onset of chest pain (<4, 4 to 6, or 6 to 12 hours), in fresh coronary thrombi causing acute myocardial infarction. The occlusive thrombi were consistently composed of platelets, fibrin, vWF, and TF from the early phase of onset, and glycoprotein IIb/IIIa and fibrin were closely associated with vWF and TF, respectively. vWF and/or TF may contribute to occlusive thrombus formation and be novel therapeutic candidates for treating patients with coronary thrombosis.

Inhibition of 5-hydroxytryptamine receptor prevents occlusive thrombus formation on neointima of the rabbit femoral artery

BACKGROUND

Thrombus propagation on disrupted plaque is a major cause of acute coronary events and serious complication after coronary intervention. 5-Hydroxytryptamine (5-HT) is a potent vasoactive and platelet-aggregating substance that is predominantly mediated by 5-HT2A receptor. However, the roles of 5-HT2A receptor in occlusive thrombus formation on disrupted plaque remain obscure.

OBJECTIVE

We investigated the role of 5-HT2A receptor in thrombus formation using a rabbit model of repeated balloon-injury.

METHODS

Three weeks after a first balloon-injury of the femoral arteries, luminal diameter, neointimal growth, and vasoconstriction by 5-HT in vitro were examined. Thrombus propagation and the role of 5-HT2A receptor after a second balloon-injury were evaluated using sarpogrelate, a selective 5-HT2A receptor antagonist.

RESULTS

Three weeks after the first balloon-injury, luminal stenosis was evident in the femoral arteries, where the neointima expressed tissue factor and 5-HT2A receptor. The hypercontractile response of the stenotic arteries to 5-HT was significantly reduced by sarpogrelate. Balloon-injury of the neointima with substantially reduced blood flow promoted the formation of occlusive thrombus that was immunoreactive against glycoprotein IIb-IIIa, 5-HT2A receptor and fibrin. Intravenous injection of sarpogrelate significantly inhibited ex vivo platelet aggregation induced by adenosine 5'-diphosphate, thrombin and collagen alone as well as with 5-HT, and significantly prevented occlusive thrombus formation in vivo.

CONCLUSIONS

The 5-HT2A receptor appears to play a crucial role in occlusive thrombus formation in diseased arteries via platelet aggregation and vasoconstriction. Inhibition of 5-HT2A receptor might help reduce the onset of acute coronary events and of acute coronary occlusion after the intervention.

Population pharmacokinetics of theophylline in very premature Japanese infants with apnoea

OBJECTIVE

To estimate the population pharmacokinetics of theophylline in very premature infants using the non-linear mixed effects modelling.

METHOD

A total of 167 serum concentration measurements obtained from routine theophylline monitoring of 107 very premature Japanese infants were collected.

RESULTS

The final pharmacokinetic parameters were CL (mL/h) = [6.98 . body weight (BW) (kg)(2.17) + 0.244 . post-conceptional age (weeks)] . 1.24(oxygen support), Vd (L) = 0.492 . BW (kg) and F = 0.660, respectively. Clearance was increased by 24% for patients receiving oxygen support. The inter-individual variabilities in clearance and apparent volume of distribution were 15.6% and 80.4%, respectively, and the residual variability was 34.2% as a coefficient of variation.

CONCLUSION

Application of the findings in this study to patient care may permit selection of an appropriate initial maintenance dosage to achieve target theophylline concentrations, thus enabling the clinician to achieve the desired therapeutic effect in very premature Japanese infants.

Tolerance mechanism of the ethanol-tolerant mutant of sake yeast

Several ethanol-tolerant mutants have been bred from industrial sake yeasts, but the mechanism of ethanol tolerance in these mutants has not been elucidated. After the determination of the entire genome sequence of Saccharomyces cerevisiae, various methods to monitor the whole-gene expression of the yeast have been developed. In this study, we used a commercially available nylon membrane on which virtually every gene of S. cerevisiae was spotted to compare expression profiles between the ethanol-tolerant mutant and its parent sake yeast to investigate the mechanism of ethanol tolerance in this mutant. As a result, we found that several genes were highly expressed only in the ethanol-tolerant mutant but not in the parent strain. These genes were known to be induced in cells that were exposed to various stresses, such as ethanol, heat, and high osmolarity, or at the stationary-phase but not at the log-phase. In the ethanol-tolerant mutant, the expression level of these stress-responsive genes was further increased after exposure to ethanol. We also found that substances such as catalase, glycerol and trehalose that may have protective roles under stressful conditions were accumulated in high amounts in the ethanol-tolerant mutant. The ethanol-tolerant mutant also exhibited resistance to other stresses including heat, high osmolarity and oxidative stress in addition to ethanol tolerance. These results indicate that the mutant exhibits multiple stress tolerance because of elevated expression of stress-responsive genes, resulting in accumulation of stress protective substances.

Angiotensin II stimulates cardiac adrenomedullin production and causes accumulation of mature adrenomedullin independently of hemodynamic stress in vivo

Adrenomedullin is a potent hypotensive peptide that may act on myocytes to inhibit hypertrophy and on fibroblasts to inhibit growth in vitro induced by mechanical stretching and angiotensin II. Adrenomedullin is processed from the inactive intermediate adrenomedullin precursor with a glycine extension, which is subsequently converted to biologically active mature adrenomedullin by enzymatic amidation. Total adrenomedullin is the sum of intermediate and mature adrenomedullin. We examined the effect of a subpressor dose of angiotensin II on the production of left ventricular adrenomedullin and on protein levels of mature adrenomedullin in the left ventricle in vivo. We also investigated whether the effect is mediated by the angiotensin II type 1 receptor. Concentrations of total and mature adrenomedullin in the left ventricle and mature adrenomedullin-to-intermediate adrenomedullin ratio were significantly increased by angiotensin II infusion, regardless of pressure overload. Total and mature adrenomedullin concentrations significantly correlated with the weight of the left ventricle. Furthermore, increased adrenomedullin gene expression and protein levels were completely suppressed by a subdepressor dose of angiotensin II type 1 receptor blocker. In conclusion, angiotensin II stimulates the production of cardiac adrenomedullin and accumulates mature adrenomedullin in the left ventricle independently of hemodynamic stress. These processes are partially regulated through the angiotensin II type 1 receptor in vivo.

Antifibrotic effect of adrenomedullin on coronary adventitia in angiotensin II-induced hypertensive rats

OBJECTIVE

The extracellular matrix (ECM) determines the structural integrity of the heart and vasculature, participating in cardiovascular remodeling. We previously reported that adrenomedullin (AM) inhibited cellular proliferation and protein synthesis of cardiac fibroblasts; however, the precise mechanisms of AM actions as an antifibrotic factor remain unknown. The purpose of this study was to examine the biological actions of AM against the profibrotic factor angiotensin II (Ang II) in coronary adventitia.

METHODS AND RESULTS

Rats with hypertension induced by Ang II infusion were administered 0.06 mug/kg/min recombinant human AM subcutaneously for 14 days. The AM infusion significantly (p<0.05) reduced the Ang II-induced increase of coronary adventitial fibroblasts expressing Ki-67 and alpha-smooth muscle actin (alpha-SMA) in the left ventricle, by 65%, and 62%, respectively, without affecting systolic blood pressure, left ventricle/body weight, or cross-sectional area of myocardial fibers. Collagen deposition of coronary arteries was reduced by the AM infusion (-24%, p<0.01), and these effects of AM were accompanied by significant reductions in gene expression of type 1 collagen (-49%, p<0.05) and transforming growth factor-beta1 (TGF-beta1) (-55%, p<0.01). In cultured cardiac fibroblasts, 10(-7) mol/L AM exerted an inhibitory effect on TGF-beta1-induced alpha-SMA expression (p<0.01) that was mimicked by 8-bromo-cAMP and attenuated by the protein kinase A inhibitor H-89.

CONCLUSION

AM decreased Ang II-induced collagen deposition surrounding the coronary arteries, inhibiting myofibroblast differentiation and expressions of ECM-related genes in rats. The present findings further support the biological action of AM as an antifibrotic factor in vascular remodeling.

Effects of interleukin-6 produced in coronary circulation on production of C-reactive protein and coronary microvascular resistance

We measured plasma levels of interleukin-6 and C-reactive protein at the orifice of the left coronary artery and at the great cardiac vein in patients who had coronary artery disease and those who had angiographically normal coronary arteries (controls). We also measured coronary microvascular resistance in the control group. We found increased levels of interleukin-6 in the coronary circulation of patients who had coronary artery disease compared with controls. This increase correlated with C-reactive protein production in the coronary circulation and coronary microvascular resistance. These findings suggest that a localized cytokine/inflammatory pathway functions in the coronary circulation and that interleukin-6 is involved in modulating coronary vascular tone.

Polynuclear growth model with external source and random matrix model with deterministic source

We present a random matrix interpretation of the distribution functions which have appeared in the study of the one-dimensional polynuclear growth (PNG) model with external sources. It is shown that the distribution, GOE2 , which is defined as the square of the Gaussian orthogonal ensemble (GOE) Tracy-Widom distribution, can be obtained as the scaled largest eigenvalue distribution of a special case of a random matrix model with a deterministic source, which have been studied in a different context previously. Compared to the original interpretation of the GOE2 as "the square of GOE," ours has an advantage in that it can also describe the transition from the Gaussian unitary ensemble (GUE) Tracy-Widom distribution to the GOE2 . We further demonstrate that our random matrix interpretation can be obtained naturally by noting the similarity of the topology between a certain noncolliding Brownian motion model and the multilayer PNG model with an external source. This provides us with a multimatrix model interpretation of the multipoint height distributions of the PNG model with an external source.

Relation of CD39 to plaque instability and thrombus formation in directional atherectomy specimens from patients with stable and unstable angina pectoris

To determine whether the expression of CD39 in coronary atherosclerotic lesions is related to plaque instability and thrombus formation, we assessed directional coronary atherectomy (DCA) specimens from patients with stable and unstable angina pectoris. CD39 immunoreactivity was decreased in culprit lesions in patients with unstable angina pectoris compared with those with stable angina pectoris, and was reduced in DCA specimens with thrombus formation. These results suggest that CD39 expressed in atheromatous plaque plays an important role in preventing acute coronary syndromes.

Adrenomedullin induces matrix metalloproteinase-2 activity in rat aortic adventitial fibroblasts

BACKGROUND

The delicate balance of the extracellular matrix (ECM) determines the stiffness of the vascular wall, and adventitial fibroblasts are involved in ECM formation by synthesizing and degrading matrix proteins. In the present study, we examined the effect of the bioactive peptide adrenomedullin (AM) on activity and expression of matrix metalloproteinases (MMPs) in cultured aortic adventitial fibroblasts.

METHODS AND RESULTS

In cultured adventitial fibroblasts isolated from aorta of adult Wistar rats, 10(-6)mol/L angiotensin II (Ang II) significantly (p<0.05) down-regulated MMP-2 activity as determined by in vitro gelatin zymography. In contrast, 10(-7)mol/L synthetic rat AM significantly (p<0.05) stimulated zymographic MMP-2 activity by 23%, increasing intracellular cAMP, and AM abolished the action of Ang II, augmenting the MMP-2 activity. Similarly, Ang II down-regulated MMP-2 protein expression assessed by Western blotting, whereas AM increased it. Furthermore, 8-bromo-cAMP, an analogue of cAMP, mimicked the effect of AM, and H-89, an inhibitor for protein kinase A (PKA), significantly decreased the basal and AM-induced MMP-2 activity.

CONCLUSION

This study provides a new insight into the biological action of AM and its intracellular signaling system of cAMP/PKA stimulating the matrix degrading enzyme MMP-2, suggesting an important role for this molecule in modulating ECM deposition in the adventitial layer.

Adrenomedullin alleviates not only neointimal formation but also perivascular hyperplasia following arterial injury in rats

Producing components of the extracellular matrix, the vascular adventitia has been recognized as an important modulator of the vascular remodeling process, which determines the vessel architecture. In this study, we examined the effect of the vasodilator peptide adrenomedullin on vascular remodeling induced by balloon injury of rat carotid arteries. Endothelial denudation with wall stretch by ballooning not only induced neointimal formation accompanied with a reduced ratio of the lumen to vessel area, but also increased the fibroblast number and collagen deposition in the adventitial layer. When compared with the saline infusion, intravenous adrenomedullin infusion at 200 ng/h for 14 days suppressed the neointimal formation (-33%, P=0.033), reversing the ratio of lumen to vessel ratio (P=0.030), without affecting systolic blood pressure. Moreover, the adrenomedullin infusion decreased the number of adventitial fibroblasts (-41%, P<0.001) and the collagen deposition (-36%, P=0.006) in the adventitial layer of the injured artery. In conclusion, the intravenous adrenomedullin infusion effectively attenuates vascular remodeling following the arterial injury via suppression of hyperplasia in the intima and adventitia, suggesting a potential of adrenomedullin as a therapeutic tool against vascular remodeling.

Increased adrenomedullin immunoreactivity and mRNA expression in coronary plaques obtained from patients with unstable angina

OBJECTIVE

To examine the expression and localisation of adrenomedullin in human coronary atherosclerotic lesions from patients with unstable angina (UAP) and stable angina (SAP), and to study the relation between adrenomedullin expression and plaque instability.

DESIGN

A retrospective observational study.

PATIENTS

Directional coronary atherectomy samples were obtained from 15 patients with UAP and 12 with SAP.

METHODS

The localisation of adrenomedullin was examined by immunohistochemistry, and adreno-medullin mRNA expression was measured by quantitative polymerase chain reaction.

RESULTS

Adrenomedullin immunoreactivity was preferentially localised in macrophages, intimal smooth muscle cells, and proliferated microvessels. The mean number of adrenomedullin positive cells in five high power fields (x 400) per specimen was higher in patients with UAP than in those with SAP (mean (SEM), 110 (13) v 76 (7); p < 0.05); and the ratio of adrenomedullin positive to total cells was higher in patients with UAP (43.0 (2.2)% v 34.2 (2.0)%; p < 0.01). More adrenomedullin mRNA was expressed in the plaque of patients with UAP than in those with SAP (60.4 (16.9)% v 9.7 (3.3)%; p < 0.01).

CONCLUSIONS

The findings suggest that adrenomedullin is involved in the development of atherosclerosis and plaque instability in human coronary arteries, in an autocrine or paracrine manner.

Adrenomedullin Administration Immediately After Myocardial Infarction Ameliorates Progression of Heart Failure in Rats

Background— Adrenomedullin (AM) is expressed in cardiac tissue, and plasma AM levels increase in patients with acute myocardial infarction (MI). This study was performed to determine whether AM administration immediately after acute MI inhibits progression of heart failure in rats.

Methods and Results— Rats were infused with 1.0 μg/h IP AM or saline over 7 days immediately after MI inducted by left coronary ligation and were examined 9 weeks after MI. Compared with the saline infusion, AM infusion significantly improved survival (59% versus 81%; P <0.05) and body weight gain (32%; P <0.01) and reduced heart weight (−28%; P <0.01), lung weight (−26%; P <0.01), left ventricular (LV) end-diastolic pressure (11.4±2.0 versus 4.0±0.6 mm Hg, mean± SEM; P <0.01), collagen volume fraction of noninfarcted LV (−39%; P <0.05), and plasma levels of endogenous rat AM (−38%; P <0.05) without affecting infarct size. To investigate the mechanism of AM actions, another series of MI rats infused with AM were killed on day 7. AM infusion had no effect on organ weights and hemodynamic parameters on day 7 of MI but significantly reduced urinary excretion of isoprostane (−61%; P <0.01) and noninfarcted LV mRNA levels of ACE (−31%; P <0.05) and p22-phox (−30%; P <0.05).

Conclusions— AM administration during the early period of MI improved the survival and ameliorated progression of LV remodeling and heart failure. This beneficial effect was accompanied by reductions in oxidative stress and ACE mRNA expression in noninfarcted LV in the AM infusion period.

Cardiac amyloidosis associated with a novel transthyretin aspartic acid-18 glutamic acid de novo mutation

A 40-year-old man presented with initial symptoms of syncope caused by restrictive cardiomyopathy and autonomic nervous system impairment, but it was confirmed that he had a novel transthyretin (TTR) variant, aspartic acid-18 glutamic acid (Glu), and a de novo gene mutation. A polymerase chain reaction-induced mutation restriction analysis with a mismatched sense primer demonstrated that he was heterozygous for TTR Glu 18. Liver transplantation was not performed because of profound weakness and severe postural hypotension. Right-sided heart failure predominated in association with low output syndrome and a gradual decrease in total QRS voltage on electrocardiogram over 5 years of follow-up. Autonomic neuropathy developed and he eventually died of both-sided heart failure at the age of 45 years. Immunohistochemical and DNA studies are important to diagnose and treat TTR-related cardiac amyloidosis.

Relation of C-reactive protein to restenosis after coronary stent implantation and to restenosis after coronary atherectomy

To determine whether the inflammatory response is equally involved in the pathogenesis of restenosis after coronary stenting and directional coronary atherectomy, we assessed restenotic lesions with immunohistochemical methods. Levels of C-reactive protein and macrophages were greater in patients with in-stent restenosis than in those with restenosis after directional coronary atherectomy. This suggests that the inflammatory response is more involved in the pathogenesis of in-stent restenosis than in restenosis after directional coronary atherectomy.

Differential gene expression of adrenomedullin receptors in pressure- and volume-overloaded heart--role of angiotensin II

Left ventricular (LV) adrenomedullin (AM) gene expression differs between pressure overload (POL) and volume overload (VOL) and angiotensin II could be a critical stimulator of AM gene expression in POL and VOL models. Calcitonin receptor-like receptor (CRLR) co-expressed with receptor activity modifying protein 2 (RAMP2) or RAMP3 functions as an AM receptor. Levels of CRLR, RAMP2 and RAMP3 mRNA that were significantly increased within 24 h returned to the basal level at 5 days after the imposition of POL in the present study. In contrast, mRNA levels of CRLR and RAMP2 gradually increased over 6 weeks after the imposition of VOL. Continuous infusion of angiotensin II stimulated LV AM gene and AM receptor gene expression independently of LV peak-systolic and LV end-diastolic pressure. The gene expression of LV AM receptors increased in different types of cardiac overload. The present study revealed an intimate association between the AM signaling system and angiotensin II.

Tumor necrosis factor-alpha downregulates adrenomedullin receptors in human coronary artery smooth muscle cells

We examined the effects of tumor necrosis factor (TNF)-alpha on the expression and functionality of adrenomedullin (AM) receptors in cultured human coronary artery smooth muscle cells. Analysis of real-time quantitative polymerase chain reactions showed that these cells abundantly express two AM receptors comprised of calcitonin receptor-like receptor (CRLR) and receptor activity-modifying protein 1 (RAMP1) or RAMP2. TNF-alpha induced time- and dose-dependent decreases in the expression of CRLR and RAMP1/2 mRNAs, thereby diminishing AM-evoked cAMP production. The suppression of these three mRNAs was unaffected by inhibiting NOS, protein kinase G, protein kinase A, superoxide formation or NF-kappaB activation.

Hepatitis B virus X protein (HBx)-induced apoptosis in HuH-7 cells: influence of HBV genotype and basal core promoter mutations

BACKGROUND

Hepatitis B virus (HBV) infection is a serious, world-wide problem. HBV genotype and basal core promoter (BCP) mutations affect the clinical course of HBV-infected patients. BCP mutations also lead to mutations at HBV X protein (HBx) codons 130/131. The functional significance of naturally occurring variants of human HBx remains largely unknown. The purpose of the study was to investigate whether HBV genotypes or double mutations affect HBx-induced apoptosis.

METHODS

We constructed genotype A, B, C, and D HBx expression vectors and HBx expression vectors with double mutations at HBx codons 130K and 131V or positions 130M and 131I using site-directed mutagenesis. A transient expression system in HuH-7 cells was established and this model was utilized to address the effect of HBx on cell viability.

RESULTS

HBx-transfected cells showed a dose-dependent decrease in cell viability by MTS assay. A subset of cells expressing HBx underwent apoptosis according to terminal transferase enzyme-mediated end labeling of DNA and caspase-3 activity. This study demonstrated that HBx can induce cell death by apoptosis in a dose-dependent manner and that HBV genotypes and double mutations did not affect HBx-induced apoptosis.

CONCLUSIONS

HBV genotypes and mutation of two amino acids directly adjacent to the conserved Kunitz domain essential for transcription activating activity of HBx did not change the pro-apoptotic activity of HBx. Further study is needed to determine whether HBV genotypes and double mutations have any effect on the function of HBx.

Possible contribution of C-reactive protein within coronary plaque to increasing its own plasma levels across coronary circulation

C-reactive protein (CRP) mRNA was detected in coronary plaque. Plasma CRP levels across the coronary circulation were increased much more in patients with unstable angina pectoris and somewhat more in those with stable angina pectoris compared with controls whose coronary arteries were angiographically normal. Thus, CRP within coronary plaque might contribute to increased plasma CRP levels across coronary circulation, particularly among patients with unstable angina pectoris.

133SUBOPTIMAL OOCYTE ACTIVATION CAUSES METHYLATION CHANGE IN TWO IMPRINTED GENES IN THE MOUSE

In mammals, the dynamic of Ca2+ oscillations induced by fertilization causes the remodeling of the parental chromosomes and activates the developmental processes. The objective of the present study was to evaluate whether the modulation of the regime of Ca2+ oscillations during the process of egg activation is capable of inducing specific chromatin modification. The sensitivity of chromatin modification during oocyte activation was evaluated by comparison of the methylation profile of Igf2r, the maternal allele of which is methylated, and H19, the maternal allele of which is unmethylated. Freshly ovulated mouse oocytes were parthenogenetically activated by a series of repetitive Ca2+ ion influxes induced by electropermeabilization of the plasma membrane in a microfluidic processor. The first treatment (T1) consisted of 24 electrical pulses (1.45kVcm−1) given every 8min for 3h in the presence of 100μM of Ca2+. The treated oocytes were almost all activated, 98% (328/338), and formed pronuclei 3 or 4h after the first pulse. The second treatment (T2) was made up of 16 electrical pulses of lower amplitude (1.12kVcm−1), given every 8 min for 2h under the same conditions. The rate of egg activation dropped to 29%, (86/298), and the time course of pronucleus formation was completed 7h after the first pulse. The remaining oocytes, 71% (212/298), extruded the second polar body, but their chromatin did not undergo full decondensation and then did not proceed further to pronucleus formation. The methylation profiles of the two imprinted genes were analyzed by using the bisulfite sequencing method. Oocytes that formed pronuclei after being subjected to either the T1 or the T2 treatment displayed methylation profiles of the two alleles similar to those of the non-treated oocytes. The Igf2r-DMR was found fully methylated on all 13 copies examined, and the H19 DMR was found mostly unmethylated (13 out of 19 copies; 6 were partially methylated). Thus, when parthenogenetic activation results in formation of a pronucleus the methylation profile of these two genes is maintained. In contrast, those from oocytes that responded by PB extrusion showed the following: fully unmethylated Igf2r-DMR copies (9/9) and partially methylated H19-DMR copies (4/11). These results reveal that rapid de novo methylating and demethylating activity are present when cells are subjected to partial activation. Thus, when the biological response of the oocyte is incomplete, that is to say, when the chromatin remains partially decondensed after suboptimal activation, both active demethylation and de novo methylation can be remarkably dynamic. While the molecular mechanism needs to be clarified, these results reveal that modulation of the process of egg activation might give new opportunities to better understand the epigenetic chromatin changes caused by fertilization.

Development of an ultrasensitive enzyme immunoassay for human proadrenomedullin N-terminal 20 peptide and direct measurement of two molecular forms of PAMP in plasma from healthy subjects and patients with cardiovascular disease

OBJECTIVE

Proadrenomedullin N-terminal 20 peptide (PAMP) processed from an adrenomedullin precursor is a potent hypotensive peptide. It was anticipated that a mature form of PAMP (m-PAMP) and an intermediate PAMP-gly existed together in the blood. To measure concentrations of PAMPs in human plasma directly, we have developed a highly sensitive enzyme immunoassay (immune complex transfer enzyme immunoassay, ICT-EIA).

DESIGN AND METHODS

PAMP was reacted simultaneously with 2,4-dinitrophenyl (DNP)-biotinyl-bovine serum albumin (BSA)-anti-PAMP Fab' conjugate and anti-PAMP Fab'-beta-D-galactosidase conjugate. The immune complex that was formed was initially trapped onto a polystyrene bead coated with anti-DNP IgG, and then transferred onto a second polystyrene bead coated with streptavidin. The resulting three-component complex was then assayed fluorometrically.

RESULTS

The detection limits of ICT-EIA for both m-PAMP and PAMP-gly were 0.1 pmol/l with as little as 10 microl of plasma, and were a hundred times higher than with conventional radioimmunoassay (RIA). Using ICT-EIA, we determined that the plasma concentrations of m-PAMP and PAMP-gly in 51 healthy volunteers were 0.51 +/- 0.19 and 1.15 +/- 0.38 pmol/l (mean +/- SD), respectively. Both plasma m-PAMP and PAMP-gly concentrations in patients with a variety of diseases, including hypertension, heart failure, chronic renal failure, and hemodialysis, were significantly higher than those in healthy subjects. In addition, both plasma m-PAMP and PAMP-gly concentrations in patients with New York Heart Association (NYHA) class I-IV heart failure were increased in proportion to clinical severity.

CONCLUSIONS

These sensitive and specific ICT-EIAs may be used as a powerful tool for investigating the cardiovascular system in patients with heart failure.

Proteolysis of ICAM-1 on human oral epithelial cells by gingipains

Cysteine proteinases (gingipains) from Porphyromonas gingivalis are considered key virulence factors of severe periodontitis and host immune evasion. Since expression of intercellular adhesion molecule-1 (ICAM-1) on gingival epithelium is indispensable in polymorphonuclear leukocyte (PMN) migration at the site of periodontitis, we examined the effects of gingipains on the expression of ICAM-1 on human oral epithelial cell lines (KB and HSC-2) by flow cytometry and Western blotting. We found that three purified forms of gingipains efficiently reduced ICAM-1 expression on the cells in a time- and dose-dependent manner. Gingipains reduced the expression on fixed cells and degraded the ICAM-1 in the cell membranes, indicating that the reduction resulted from direct proteolysis. They then disturbed the ICAM-1-dependent adhesion of PMNs to the cells. These results indicate that gingipains cleave ICAM-1 on oral epithelial cells, consequently disrupting PMN-oral epithelial cell interaction, and are involved in immune evasion by the bacterium in periodontal tissues.

Distribution of hepatitis B viral genotypes and mutations in the core promoter and precore regions in acute forms of liver disease in patients from Chiba, Japan

BACKGROUND

Although it has been reported that different hepatitis B virus (HBV) genotypes induce different clinical characteristics in patients with chronic liver diseases (CLD), there have been few reports that have detailed the distribution of HBV genotypes in acute forms of liver disease.

METHODS

HBV genotypes were determined in 61 patients who had acute forms of liver disease (45 had acute self limited hepatitis (AH) and 16 had fulminant hepatitis (FH)) and in 531 patients with CLD, including 19 patients with severe acute exacerbation of CLD. We also analysed the enhancer II, core promoter, and precore region sequences for the presence of mutations.

RESULTS

Expression of genotype B in patients with acute forms of liver disease was significantly greater than in those with CLD (39.3% v 11.7%, respectively; p<0.001). Furthermore, expression of genotype B was significantly greater in patients with FH than in those with AH (62.5% v 31.1%, respectively; p=0.027). The precore mutation A1896 and the core promoter mutation at nt 1753 and 1754 were found more frequently in FH than in AH, and genotype B was predominant in FH regardless of the presence of these mutations.

CONCLUSIONS

HBV genotype B was found more frequently in patients with acute forms of liver disease than in patients with CLD, and more frequently in patients with FH than in those with AH. These results suggest that this HBV genotype may induce more severe liver damage than other viral genotypes, at least in patients from Chiba, Japan.

Long-term hypoxia changes myometrial responsiveness and oxytocin receptors in the pregnant ewe: differential effects on longitudinal versus circular smooth muscle

Previous studies from our laboratory demonstrated that long-term hypoxia (LTH) altered in vitro contractile responses to oxytocin in full-thickness myometrial strips from pregnant sheep. The present study was designed to determine, first, if the reduced contractile response to oxytocin following LTH is the result of combined effects on longitudinal and circular smooth muscle or if the effect is specific to a single muscle layer and, second, if the reduced contractile response to oxytocin following LTH is caused by changes in oxytocin-receptor protein. Pregnant ewes were maintained at high altitude (3820 m) from Day 30 to Days 137-142 of gestation, when the ewes were killed for collection of myometrial tissue. Tissue was also collected from age-matched, normoxic controls. Longitudinal and circular layers were separated, length-tension curves generated to determine optimal resting tension, and all strips exposed to increasing half-log doses of oxytocin ranging from 10-12 to 10-6.5 M. The expression of oxytocin-receptor protein was measured using Western blot analysis. We found that LTH did not affect KCl-induced contraction of either smooth muscle layer, whereas the sensitivity of both myometrial layers to oxytocin was altered. A decreased maximum contractile response of the circular layer to oxytocin was also observed. Additionally, LTH decreased expression of oxytocin-receptor protein in the circular layer and increased levels in the longitudinal layer. Results from the present study indicate that LTH alters contractile responses and oxytocin-receptor protein expression in a layer-specific manner in the pregnant sheep myometrium.

Orexin-A (hypocretin-1) impairs Morris water maze performance and CA1-Schaffer collateral long-term potentiation in rats

Glucose-sensitive neurons in the lateral hypothalamic area produce orexin-A (hypocretin-1) and orexin-B (hypocretin-2) and send their axons to the hippocampus, which predominantly expresses orexin receptor 1 showing a higher sensitivity to orexin-A. The purpose of the present study was to assess the effects of orexin-A on the performance of Wistar rats during the Morris water maze test and then to determine the effects of orexin-A on both the long-term potentiation and long-term depression in Schaffer collateral/commissural-CA1 synapses in hippocampal slices. The results of the Morris water maze test show that 1.0 and 10 nmol of orexin-A, when administered intracerebroventricularly, retarded spatial learning. A probe test examined after training of water maze task also showed an impairment in spatial memory. The results of an electrophysiological study using hippocampal slices demonstrated that 1.0 to 30 nM of orexin-A applied to the perfusate produces a dose-dependent and time dependent suppression of the long-term potentiation. In addition, the long-term depression was not affected by orexin-A. The results of a paired-pulse facilitation experiment indicated that the effects of orexin-A were post-synaptic and not due to presynaptic transmitter release. These results show that orexin-A impairs spatial performance and these impairments can be attributed to a suppression of long-term potentiation in the Schaffer collateral-CA1 hippocampal synapses.

Angiotensin II modulates gene expression of adrenomedullin receptor components in rat cardiomyocytes

Both adrenomedullin (AM) and angiotensin II (Ang II) are locally-acting hormones in the cardiac ventricles. Previously we reported that AM inhibits Ang II-induced hypertrophy of cultured rat neonatal cardiomyocytes. In this study, we examined whether Ang II affects the gene expression of the AM receptor components of calcitonin-receptor-like receptor (CRLR) and receptor-activity-modifying protein (RAMP) in rat cardiomyocytes. The mRNA levels of RAMP1 and RAMP3 were significantly elevated following 24-h treatment with Ang II without a change of those of RAMP2 and CRLR. AM increased the intracellular cAMP level and the cAMP accumulation by AM was significantly amplified by the 24-h preincubation with Ang II. The effects of Ang II on RAMP1 and RAMP3 expression were abolished by an Ang II type 1 (AT1) receptor antagonist, but not by an AT2 receptor antagonist. Thus, Ang II modulates gene expression of the AM receptor components via AT1 receptor, suggesting alteration of AM actions by Ang II in cultured rat cardiomyocytes.

Differential increase in natriuretic peptides in elite dynamic and static athletes

The echocardiographic measures and plasma concentrations of either atrial natriuretic peptide (ANP) or brain natriuretic peptide (BNP) were compared in elite judo practitioners (static athletes), elite marathon runners (dynamic athletes) and healthy controls to investigate the relationship between the different types of left ventricular (LV) hypertrophy and plasma concentrations of natriuretic peptides in athletes. The LV mass and LV wall thickness of marathon runners and judo practitioners were significantly greater than those of controls. The LV end-diastolic dimension index was significantly larger in the marathon group, but smaller in the judo group. The left atrial dimension (LAD) index was significantly larger only in marathon runners. Plasma BNP concentrations were higher in both the judo and marathon groups than in controls, and positively correlated with LV mass as well as with deceleration time. Plasma ANP concentrations were significantly higher in marathon runners than in the controls and judo groups, and positively correlated with the LAD index, but negatively correlated with ejection fraction. Multivariate analyses showed that the type of athlete and LAD index were independent predictors of plasma BNP and ANP concentrations, respectively. Thus, there is an intimate link between plasma concentrations of natriuretic peptides and cardiac morphology in different types of athletes.

Hyperkalemia induced by the calcium channel blocker, benidipine

A 73-year-old hypertensive, non-diabetic woman without obvious renal dysfunction had frequently been hyperkalemic over four years after receiving antihypertensive drugs including the calcium channel blocker (CCB) benidipine. One week after all medications were accidentally discontinued, the serum potassium level returned to normal. After we obtained the informed consent of the patient, benidipine alone was administered again for over two weeks and hyperkalemia developed once more. This previously uncommon side effect of hyperkalemia induced by benidipine is not very serious but it is apt to be overlooked. Since CCBs are now widely prescribed, the development of hyperkalemia should be considered.

Two cases of pheochromocytoma associated with tetralogy of Fallot

We report two cases of pheochromocytoma combined with tetralogy of Fallot who showed different clinical courses. Case 1 was a 45-year-old woman with a history of radical operation for tetralogy of Fallot at 20 years of age. She presented with sudden hypertensive attack, and was diagnosed with pheochromocytoma of the left adrenal gland. She was treated surgically, and her high plasma noradrenaline level normalized. Case 2 was a 41-year-old woman who had been suffering from severe cyanosis due to tetralogy of Fallot throughout her life. A palliative operation had been performed at 7 years of age, but a radical operation had not been performed. She has had resistant hypertension since 38 years of age. She was diagnosed as having pheochromocytoma of the left adrenal gland at 41 years of age, but surgery was not performed. She was pharmacologically treated with doxazosin, followed by bisoprolol. Her symptoms somewhat improved, although she continued to have high plasma levels of noradrenaline and adrenomedullin. The combination of pheochromocytoma with tetralogy of Fallot or cyanotic congenital heart disease is rare; however, pheochromocytoma and congenital heart disease might be related through chronic hypoxia and/or gene abnormalities. The presence of pheochromocytoma worsens the hemodynamic state in patients with congenital heart disease regardless of whether radical surgery for congenital heart disease had been performed. Differential diagnosis of pheochromocytoma could be paramount in congenital heart disease patients who show unexpected or unusual symptoms.