Functional interference between estrogen-related receptor alpha and peroxisome proliferator-activated receptor alpha/9-cis-retinoic acid receptor alpha heterodimer complex in the nuclear receptor response element-1 of the medium chain acyl-coenzyme A dehydrogenase gene

We undertook a study of molecular interference of nuclear orphan receptors. Nuclear receptor response element-1 (NRRE-1) from the human medium-chain acyl coenzyme A dehydrogenase (MCAD) gene promoter was shown to contain three hexamer elements (site 1 through 3) that are known to interact with a number of nuclear receptors including chicken ovalbumin upstream promoter transcription factor (COUP-TF) and estrogen-related receptor alpha (ERRalpha). We demonstrated that the peroxisome proliferator-activated receptor alpha/9-cis-retinoic acid receptor alpha (PPARalpha/RXRalpha) heterodimer complex can also bind to the two hexamer repeat sequences (between site 1 and site 3) arranged as an everted imperfect repeat separated by 14 bp (ER14). Mutations of the putative core elements have shown that these three sites are differentially involved in ERRalpha and PPARalpha/RXRalpha binding. Homodimer of ERRalpha was shown to interact between site 1 and site 3 (ER14). To date, no nuclear receptor is known to bind to response elements over such long intervals. Interestingly, site 1 was shown to be essential for ERRalpha binding while site 3 supports its binding only in the presence of site 1. Furthermore, it was shown that the binding profile of ERRalpha and PPARalpha/RXRalpha are competitive rather than making a high order complex within NRRE-1. At the cellular level, transcriptional activation driven by the PPARalpha/RXRalpha complex was counteracted by the expression of ERRalpha in HeLa cells. These results suggest that ERRalpha and PPARalpha/RXRalpha could interfere with each other's function through binding to similar DNA elements, thereby finetuning the transcriptional outcome of the target gene. Our findings suggest a mechanism whereby multiple nuclear receptors can activate or repress DNA binding or transcription via a single pleiotropic regulatory element.

Alteration in haemodynamics and pathological changes in the cardiovascular system during the development of Type 2 diabetes mellitus in OLETF rats

AIMS/HYPOTHESIS

The process of cardiovascular complications in Type 2 diabetes mellitus (DM) is unclear. We investigated pathophysiological changes of the heart and vessels in the Otsuka Long-Evans Tokushima Fatty (OLETF) rat Type 2 DM model during a long time period.

METHODS

Echocardiography was carried out at 22 and 62 weeks of age of OLETF ( n=10, each) and age-matched Long-Evans Tokushima Otsuka (LETO) rats ( n=10, each) as a reference. Haemodynamic measurements and histological examinations of the heart and the coronary and aortic vascular walls were done.

RESULTS

The left ventricular (LV) maximal -dP/dt was reduced in OLETF rats at 62 weeks (-1085+/-35 mmHg/s) less than that at 22 weeks (-1892+/-396 mmHg/sec, p<0.05) and in LETO rats at 62 weeks (-1306+/-200 mmHg/sec, p<0.05). Wall thickening of intramyocardial coronary arteries, capillary tortuosity and thickening of basement membrane were evident in OLETF rats at 62 weeks. Intimal and medial wall thickening of the aorta were prominent in OLETF rats at 62 weeks (15+/-2.2 and 90+/-6.6 micro m, in LETO rats at 62 weeks, 2+/-0.4 and 65+/-5.2 micro m, p <0.05, and in OLETF rats at 22 weeks, 7+/-4.6 and 71+/-6.0 micro m, p<0.05, respectively).

CONCLUSIONS/INTERPRETATION

In the Type 2 DM model, angiopathy, especially in coronary arteries including small vessels, as well as a LV relaxation abnormality, are induced in a late stage of DM. These are considered to be important complications in Type 2 DM.

Amicrobial pustular dermatosis in two patients with immunological abnormalities

We report two patients with severe amicrobial pustular dermatosis with immunological abnormalities: a 63-year-old woman with a 30-year-history of discoid lupus erythematosus and sicca syndrome, and a 35-year-old woman with high levels of gamma-globulinemia and positive antinuclear antibodies. Both patients presented with crusty and eroded erythematous plaques studded with aseptic pustules on the back, face, and scalp. Histological examination showed acanthosis, neutrophilic exocytosis to the epidermis, and neutrophilic and lymphocytic infiltration with nuclear dust in the dermis. These patients were diagnosed as having "amicrobial pustulosis associated with autoimmune diseases". The eruptions improved with combination treatment of oral prednisolone with cyclosporin A or diaminodiphenylsulphone. Although the pathogenesis remains unclear, amicrobial pustular dermatosis might be one of the cutaneous complications in autoimmune diseases.

Increased plasminogen activator inhibitor-1 and apolipoprotein (a) in coronary atherectomy specimens in acute coronary syndromes

BACKGROUND

Although increased tissue factor expression is known in vulnerable plaques, there is no reported study to compare plaque fibrinolysis in stable and unstable plaques. This study investigates the extent of plasminogen activator inhibitor-1 (PAI-1) and apolipoprotein (a) [apo(a)] in the plaques of different types of coronary artery disease as well as the correlation between these molecules and infiltration of macrophages to plaques.

METHODS

Using immunohistochemical staining, we examined PAI-1 expression and apo(a) deposition in coronary atherosclerotic specimens obtained by directional coronary atherectomy from 19 patients with acute myocardial infarction (AMI), 12 with unstable angina pectoris (UAP), and 13 with stable angina pectoris (SAP). The percentages of the total areas of specimens stained with PAI-1 or apo(a) were estimated by an NIH image program. The proportion of macrophages as a percentage of all cells in plaques was calculated as the macrophage density.

RESULTS

We found significantly higher percentages of total areas of specimens stained with PAI-1 in AMI (25.5 +/- 8.6%, P < 0.001) and UAP (22.2 +/- 10.4%, P < 0.005) than in SAP (9.5 +/- 5.0%), as well as with apo(a) (AMI; 11.7 +/- 7.1%, P < 0.005, UAP; 11.1 +/- 5.5%, P < 0.01 versus SAP; 3.9 +/- 1.5%). Linear regression analysis of all the samples showed a correlation between PAI-1 or apo(a) and macrophage density (PAI-1: r = 0.75, P < 0.001 and apo(a): r = 0.56, P < 0.001).

CONCLUSIONS

Our results suggest a possible contribution of increased PAI-1 and apo(a) in plaques to the pathogenesis of acute coronary syndromes including impaired fibrinolysis.

Attenuation of angiotensin II-mediated coronary vasoconstriction and vasodilatory action of angiotensin-converting enzyme inhibitor in pacing-induced heart failure in dogs

OBJECTIVES

We investigated the changes in coronary vascular resistance caused by angiotensin II, angiotensin-converting enzyme (ACE) inhibition and angiotensin II type 1 or 2 receptor (AT(1)R and AT(2)R, respectively) antagonists in chronic heart failure (CHF).

BACKGROUND

Angiotensin II is an intense vasoconstrictor, and increased angiotensin II in CHF might exert significant vasoconstriction.

METHODS

Eleven dogs were studied. Before and after three and five weeks of rapid pacing, coronary flow dynamics were evaluated by the coronary pressure-flow relationship (PFR) in long diastole, before and after intracoronary injection of angiotensin II, the ACE inhibitor enalaprilat, the AT(1)R antagonist L158,809 or the AT(2)R antagonist PD123319.

RESULTS

Before rapid pacing, angiotensin II reduced the slope of PFR (1.16 +/- 0.08 to 0.81 +/- 0.07 ml/min/100 g left ventricular mass per mm Hg; p < 0.01) and increased the perfusion pressure at which coronary flow ceased (zero-flow pressure [P(f) = 0]), whereas enalaprilat did not change either of them. After rapid pacing, angiotensin II did not change the slope or P(f) = 0. In contrast, enalaprilat increased the slope (three weeks: 1.20 +/- 0.05 to 1.50 +/- 0.03; five weeks: 1.25 +/- 0.19 to 1.37 +/- 0.08; both p < 0.05) and decreased P(f) = 0 after three weeks of pacing, but not after five weeks. Pretreatment with the bradykinin antagonist HOE-140 attenuated the enalaprilat-induced increase in coronary blood flow. L158,809 and PD123319 had no effect both before and after rapid pacing.

CONCLUSIONS

This suggests that the coronary vasoconstrictive effect of angiotensin II would disappear and the vasodilatory effect of the ACE inhibitor, partly through bradykinin, would be enhanced in the early stage of CHF.

Early growth-responsive-1-dependent manganese superoxide dismutase gene transcription mediated by platelet-derived growth factor

Manganese superoxide dismutase Mn-SOD plays a major role in protecting mitochondria from oxidative damage. Overexpression of Mn-SOD maintains cell survival under conditions that lead to apoptotic death. In addition to the antioxidative enzyme, platelet-derived growth factor (PDGF) is a principal survival factor that inhibits apoptosis and promotes proliferation by activating survival signaling pathways in various cells. Here we show that PDGF induced the expression of the Mn-SOD gene in NIH3T3 cells, and its induction was associated with early growth response-1 (Egr-1), a transcription factor. An electrophoretic mobility shift assay demonstrated that Egr-1 bound to the proximal promoter of the Mn-SOD gene in response to PDGF. The proximal promoter region of Mn-SOD was shown to be transcriptionally responsive to both basal and PDGF stimulation by transfection studies. Forced expression of Egr-1 in the cells activated Mn-SOD transcription in a dose-dependent manner. The pathway by which PDGF induced Egr-1 involved the mitogen-activated protein kinase kinase-1 (MEK1) and extracellular signal-regulated kinases 1 and 2 (ERK1/2), because the effect of PDGF on the induction of Egr-1 was blocked by U0126, a specific MEK1 inhibitor. These findings indicate that the induction of Mn-SOD is part of the anti-apoptotic properties mediated by PDGF.

Complement and polymorphonuclear leukocyte activation each play a role in determining myocardial ischemia-reperfusion injury

Cobra venom factor (CVF) transiently activates polymorphonuclear leukocytes (PMN) by complement activation, followed by rapid complement depletion and gradual reversal of PMN activation. Utilizing these sequential changes caused by CVF, the individual and combined effects of complement and PMNs on myocardial infarct size (IS) were investigated. Rats were treated with CVF, and/or anti-PMNs. Complement was depleted, but circulating PMNs were being activated at 4h after CVF administration, and at 36h after, complement was depleted, but PMNs were in a near basal condition. Under anesthesia, the rats had a 30-min coronary occlusion followed by 6h of reperfusion. The IS was assessed by tetrazolium staining. CVF, as well as anti-PMNs, reduced myeloperoxidase (MPO) activity in the risk area and the reduced MPO resulted in a reduced IS, which was also the effect of anti-PMNs, but complement depletion by CVF, during which circulating PMNs were activated, failed to reduce the IS despite low MPO activity. These results suggest that complement and the condition of PMNs each play a role in determining the IS, and ischemic reperfusion injury might be produced even by relatively low myocardial MPO activity.

Mechanism for the reduction of telomerase expression during muscle cell differentiation

Telomerase, the reverse transcriptase that maintains telomere DNA, is usually undetectable in adult human tissues, but is positive in embryonic tissues and in cancers. However, in rodents, several organs of normal adult animals express substantial amounts of telomerase activity. To elucidate relevant control mechanisms operating on the tissue-specific expression of telomerase in rodents, we examined the transcriptional regulation of telomerase reverse transcriptase (mTERT) gene in muscle cell differentiation. Reverse transcriptase-polymerase chain reaction analysis showed that the reduction of telomerase activity was caused by the decrease of mTERT mRNA level during myogenesis. Transfections of mTERT promoter showed that the proximal 225-base pair region is the core promoter responsible for basal transcriptional activity and also participates in the reduced transcription after muscle differentiation. Electrophoretic mobility shift assays showed that this region contained the GC-boxes, which bind to Sp1 family proteins, and the E-box, which binds to c-Myc. Furthermore, DNA binding activities of Sp1, Sp3, and c-Myc were down-regulated during myogenesis. These data suggest that Sp1, Sp3, and c-Myc have critical roles of TERT transactivation in mouse, and the lack of these transcription factors cause down-regulation of mTERT gene expression in muscle cells differentiation.

Continuous observation of superoxide generation in an in-situ ischemia-reperfusion rat lung model

To investigate the time course of superoxide generation in ischemia-reperfusion in the in-vivo rat lung, the present study used an enhanced chemiluminescence method with 2-methyl-6-[p-methoxyphenyl]-3,7-dihydroimidazo[1, 2-alpha]pyrazin-3-one (MCLA) as a specific probe. The right pulmonary artery was occluded for 120 min, followed by 90-min reperfusion. Chemiluminescence induced by MCLA was continuously monitored by a photomultiplier exposed to the right lung. Chemiluminescence increased gradually in 30 min of reperfusion and remained elevated throughout reperfusion. The ratio of the luminescence count during reperfusion to the preischemic value increased to 2.20+/-0.31 (mean+/-SEM) (p<0.02 vs preischemic level), 2.50+/-0.39 (p<0.005), and 2.69+/-0.44 (p<0.005), at 30, 60, and 90 min of reperfusion, respectively. Bolus administration of superoxide dismutase during the reperfusion period significantly attenuated the chemiluminescence by 45.0+/-6.7% (p<0.01). The present results suggest that increasing oxygen radical formation leading to ischemia-reperfusion lung injury may occur even after a short period of occlusion of the pulmonary artery alone in vivo.

Multiple endothelial injury in epicardial coronary artery induces downstream microvascular spasm as well as remodeling partly via thromboxane A2

OBJECTIVES

The study was undertaken to develop a coronary microvascular spasm model in pigs by repeated epicardial coronary artery endothelial injury.

BACKGROUND

The pathophysiologic mechanisms responsible for coronary microvascular spasm remain unclear, in large part because a suitable animal model has yet to be found.

METHODS

Balloon endothelial denudation was done just distal to the site of an implanted Doppler flowmeter in the left anterior descending coronary artery (LAD) every two weeks for a total of four times. Changes in LAD blood flow by intracoronary administration of vasoactive agents were assessed before each denudation.

RESULTS

In the epicardial LAD endothelial denudation pigs, decreases in LAD blood flow caused by acetylcholine were augmented. Before denudation, it was - 15 +/- 4%, and at week 8 (i.e., two weeks after the fourth denudation) it was -100% (i.e., zero flow [p < 0.01]). The LAD flow changes in response to 5-hydroxytryptamine (5-HT) changed from an increase to a decrease, accompanied by medial thickening of microvessels in the LAD perfusion area. These flow responses were observed without significant changes in LAD diameter. In contrast, the LAD blood flow responses to acetylcholine and 5-HT did not change throughout the experiment in pigs given aspirin and a thromboxane A2 (TXA2) synthase inhibitor orally.

CONCLUSIONS

This microvascular spasm model indicates that hypersensitivity to vasoactive substances in the microvascular beds as well as microvascular remodeling are brought about partly through TXA2. This model should be useful for examining the pathophysiology and treatment of microvascular angina.

Prediction of embolism in atrial fibrillation: classification of left atrial thrombi by transesophageal echocardiography

The current study was undertaken to clarify the relationship between cerebral/arterial embolism and the morphology of left atrial thrombi. Forty-one patients with atrial fibrillation and left atrial thrombi were followed for 1 year, using transesophageal echocardiography (TEE) to study how the shape, site, movability, number and maximum dimension of left atrial thrombi are related to embolism. Left atrial thrombi were classified by their shape and movability into movable ball (MB) type (n=13), fixed ball (FB) type (n=17) and mountain (MN) type (n=11). The thrombi were also classified by location into the interior section (n=3), middle section (n=8), and the entrance section (n=19) of the left atrial appendage, and the section outside of the left atrial appendage (n=11). The rate of embolism in the MB-type group was significantly higher than that in the other groups (ie, MB 76.9% vs FB 17.6% (p<0.01) vs MN 9.1%; p<0.01), which indicates that the MB-type thrombus is an important risk factor for cerebral/arterial embolism.

Effects of unstimulated polymorphonuclear neutrophils on porcine distal coronary artery tone

Recently, it has been demonstrated that polymorphonuclear neutrophils (PMNs) affect coronary vascular tone. We have reported that unstimulated PMNs constrict the porcine proximal coronary artery. However, the mechanism(s) of interaction between PMNs and coronary artery and the regional differences in susceptibility of the coronary arterial tree have not been fully explored. We examined changes in the isometric tension of porcine distal coronary arterial rings caused by unstimulated PMNs, in which the levels of superoxide anion detected by the cytochrome C method were slight when unstimulated and significant when stimulated with A23187. Unstimulated PMNs relaxed the distal coronary artery and the effect was suppressed by endothelial denudation, indomethacin and the prostacyclin synthetase inhibitor, tranylcypromine. During vasorelaxation, prostacyclin was produced (n=8, with without relaxation; 596 +/- 76/247 +/- 26 pg/ml, p < 0.01) and was considered, therefore, to be the vasodilatory substance responsible for the action. These results suggest that PMNs modulate coronary arterial tone via an interaction between PMNs and endothelium and the release of vasodilating prostaglandins, of which prostacyclin is considered to be one of the substances responsible. Further, the effect differed markedly depending on the site of the coronary artery. In vivo, coronary artery tone is complexly regulated, therefore, the relative contribution of the present PMN-endothelial cell interaction observed in vitro is unclear.

A NF-kappaB p65 subunit is indispensable for activating manganese superoxide: dismutase gene transcription mediated by tumor necrosis factor-alpha

Expression of the manganese superoxide dismutase (Mn-SOD) is induced by tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), and lipopolysaccharide (LPS). Recently, a TNF-responsive element (TNFRE) was identified within the second intron of the murine Mn-SOD gene. The 5' CCAAT/enhancer binding protein (C/EBP)-related region within the TNFRE was responsive to TNF, whereas the 3' NF-kappaB-related region alone was not. This report describes the minimal promoter region of the Mn-SOD gene and investigates the cis-acting elements and trans-acting factors responsible for TNF-alpha-induced Mn-SOD gene expression. Reporter plasmid transfection studies demonstrated that inducible transcription factors enhanced the transcriptional activity of the Mn-SOD gene through the intronic enhancer region. Electrophoretic mobility shift assays demonstrated that after TNF-alpha stimulation, p50 and p65 NF-kappaB subunits bound specifically to the newly identified NF-kappaB transcription factor-binding site, distinct from the previously described NF-kappaB site, within the intronic enhancer region. In addition, site-directed mutagenesis and cotransfection studies demonstrated that the NF-kappaB p65 subunit enhanced the transcriptional activity of the Mn-SOD gene through the newly identified NF-kappaB site. These results show that a NF-kappaB p65 subunit is mainly involved in the molecular mechanisms controlling TNF-alpha-mediated Mn-SOD gene transcription.

Apoptosis in relevant clinical situations: contribution of apoptosis in myocardial infarction

Myocardial infarction is associated with increased TUNEL-positivity in cardiac resident and infiltrated cells. Apoptosis of proliferated interstitial myofibroblasts and infiltrated inflammatory cells may have a role in terminating tissue repair processes after infarction. Lateral and endocardial border zones of infarction within the risk area have frequent appearance of TUNEL-positive cardiomyocytes. Although the typical ultrastructural morphology of apoptosis has rarely been detected in ischaemic cardiomyocytes, there are many reports in which the TUNEL method was used for assessment of cardiomyocyte apoptosis. It has become evident that TUNEL-positivity reflects a wide range of cellular conditions; viable cells undergoing DNA repair, apoptosis, and necrosis. Therefore, it is controversial whether TUNEL-positive cardiomyocytes in infarcted myocardium are all apoptotic. Methods which will be more specific for identifying apoptosis are required for future study. TUNEL-positivity can be attenuated by anti-apoptotic interventions such as inhibition of caspases, mitochondrial protection, free radical scavenging, and some conventional pharmacotherapies. However, it remains to be determined whether anti-apoptotic interventions result in satisfactory reduction of infarct size. The injurious impact of myocardial ischaemia comes from a mixture of pro-apoptotic and necrosis-promoting signals, and the target of both signals is mitochondria. Through a common pathway they may cause permeability transition. Interventions which act only at the post-mitochondrial stage of apoptosis may fail to reduce infarct size, whereas those acting at pre-mitochondrial and mitochondrial stages may reduce infarct size. Progress in investigating the basic mechanisms of apoptosis and recognition of the modes of cardiomyocytes death will contribute to advances in cardioprotective therapy in myocardial infarction.

A 92-year-old man with systemic lupus erythematosus who developed acute lupus pneumonitis

We describe a 92-year-old male patient with systemic lupus erythematosus (SLE) who had sudden onset of thrombocytopenia and developed acute lupus pneumonitis (ALP). Although steroid pulse therapy was effective for ALP, he developed complicated bacterial pulmonary disease. This patient is the oldest ever reported to have contracted SLE.

[Changes in diameter size and F-actin expression in the myocytes of patients with diabetes and streptozotocin-induced diabetes model rats]

Diabetes mellitus may be an independent risk factor for disturbance of cardiac function, but the detailed mechanism remains unclear. In the present study, histological examinations were carried out on 25 hearts from diabetes model rats as well as myocardial biopsy materials from patients with diabetes (n = 25). The mean diameter of the cardiac myocytes in humans was 12.2 +/- 0.5 microns in the control group of patients without diabetes mellitus or hypertension (n = 6), 13.7 +/- 0.8 microns in the hypertension group (n = 3), 9.0 +/- 1.7 microns in the diabetes group (n = 8), and 11.9 +/- 2.0 microns in the diabetes with hypertension group (n = 8). The cardiac myocytes of diabetic patients appeared to be atrophic. Comparison of the size of myocytes in the control rats vs streptozotocin-induced diabetes model rats (n = 7, each) was 5.4 +/- 0.2 vs 5.2 +/- 0.3 microns at 2 weeks; 5.9 +/- 0.1 vs 4.9 +/- 0.9 microns at 12 weeks, and 5.7 +/- 0.1 vs 4.0 +/- 0.2 microns at 24 weeks, respectively, and gradually decreased in streptozotocin rats with aging. Immuno-histochemistry with phaloidin was used to assess F-actin in the cardiac myocytes. The relative cross-sectional area of F-actin in the cardiac myocytes of streptozotocin rats was compared to that in non-streptozotocin rat myocytes. F-actin fluorescence in streptozotocin rats was 89.9 +/- 3.9% at 2 weeks, 77.9 +/- 6.4% at 12 weeks, and 56.8 +/- 5.7% at 24 weeks, indicating a decrease in F-actin. These results suggest that the smaller myocytes observed in patients with diabetes and streptozotocin rats are related to the decrease in F-actin in myocytes.

Systemic effects of the occlusal destruction in guinea pigs

Although there is an increasing amount of information pertaining to the systemic effects of malocclusion, its mechanisms still remain unclear in many ways. This study was conducted to find out the systemic effects of the occlusal destruction in guinea pigs. The animals showed an abnormality in posture and a reversal of the T wave in electrocardiogram (ECG) about 6 days after the grinding of all molar teeth. All the animals died about 7 days after the occlusal destruction. We established the optimal condition of occlusal destruction for the induction of the above symptoms in guinea pigs: at least 6 molars, both side premolar, 1st and 2nd molar of upper jaw, because of the ease for repair. The following results were obtained: 1. The experimental group died about 5 days earlier than the fasting group. 2. The animals could not hold their head positions and dropped the head to the earth. 3. The animals died about 12 hours after the onset of postural abnormality. 4. Ninety percent of the animals with postural abnormalities showed T wave inversion on ECG. 5. None of the above symptoms occurred with bite rising. These results indicate that occlusal destruction affects head position, preventing the animals to hold their head positions and causing the head to drop to the ground. Occlusal destruction may also cause abnormality of the masticatory muscles, which control posture and modulate cardiac function via the trigeminal system. This experimental model is suitable for the analysis of the systemic effects of occlusal destruction.

Dissociation of chronotropic and inotropic responses in the rat heart during sympathetic stimulation

It is not fully resolved how the chronotropic and inotropic responses alter depending on the strength or duration of stimulation, and how the alpha-vasoconstrictor effect competes with metabolic vasodilation during sympathetic stimulation. The present study investigated the effects of differential frequency stimuli on these responses in rat hearts during sympathetic stimulation while keeping the left ventricular end-diastolic volume constant. The heart was perfused at a constant flow or pressure with a modified Krebs-Henseleit solution. Electrical stimulation of sympathetic nerves (SNS) was performed at 4 frequencies (0.2, 0.5, 1 and 3 Hz) for 90 s in pithed rats without or with an a or alpha2 adrenergic receptor antagonist. The heart rate progressively increased during 3-Hz SNS (33+/-10% at 30s, 38+/-14% at 90s), whereas the inotropic action peaked at about 30s and then decreased (left ventricular systolic pressure +23+/-8% at 30s, -1+/-13% at 90s). This phenomenon indicates a negative staircase, in spite of a gradual increase in norepinephrine release. The reduction of contractility did not differ from that shown by constant atrial pacing with an equivalent rate. The coronary alpha1-vasoconstrictor response was competitive with metabolic vasodilation only in the early phase of stimulation and the alpha2-vasoconstrictor action had little contribution to the regulation of coronary circulation. The fact that these results differ from previous findings suggests that sympathetic regulation of the heart should be reconsidered, although direct application of the present results to humans is not clear because of species differences.

Augmented basal nitric oxide production contributes to maintenance of coronary blood flow in dogs with pacing-induced heart failure

It remains controversial whether basal nitric oxide (NO) production in coronary resistance vessels in heart failure is enhanced or not. A transonic Doppler flow probe was placed around the left anterior descending coronary artery, and complete atrioventricular block was produced in fifteen dogs. The coronary pressure-flow relationships during long diastole were analyzed without and with pacing-induced heart failure. Three weeks after pacing at 240/min, plasma norepinephrine and renin activity significantly rose. Right atrial pressure and left ventricular end-diastolic pressure increased, and cardiac output and coronary perfusion pressure decreased; however, mean coronary blood flow did not change after pacing (55 +/- 5 to 52 +/- 5 ml/min/100 g, mean +/- SEM). The slope of the diastolic coronary pressure-flow relationship became steeper (1.22 +/- 0.13 to 1.62 +/- 0.09 ml/min/100 g/mmHg, p < 0.05) with a slight increase in the measured zero-flow pressure (29.5 +/- 1.1 to 32.8 +/- 1.5 mmHg, p < 0.05) after pacing. After pretreatment with indomethacin, administration of NG-nitro-L-arginine methyl ester caused an equal increase in the zero-flow pressure before (31.4 +/- 1.7 to 39.2 +/- 2.2 mmHg, p < 0.05) and after heart failure (33.9 +/- 2.5 to 41.6 +/- 2.2 mmHg, p < 0.05), and more decline of the slope of the coronary pressure-flow relationship in heart failure (1.86 +/- 0.22 to 1.20 +/- 0.05 ml/min/100 g/mmHg, p < 0.05) than before heart failure (1.11 +/- 0.12 to 1.05 +/- 0.11 ml/min/100 g/mmHg, N.S.). This indicates that in failing hearts the vasodilatory action of NO in small vessels predominates despite the presence of several vasoconstricting factors. These results suggest that coronary blood flow is maintained despite detrimental hemodynamic and activated neurohumoral factors in the initial stage of heart failure, and that increased basal NO production plays a central role in the maintenance of basal coronary blood flow.

Effects of cardiac contraction and increased coronary sinus pressure on the coronary arterial pressure-flow relationship

Increased coronary sinus (CS) pressure and cardiac contraction impair coronary inflow independently. However, it has not been determined how the coronary pressure-flow relationship is strongly affected by changes in CS pressure in the beating heart compared to the non-beating heart. The purpose of this study was to evaluate the combined mechanical effects of cardiac contraction and increased CS pressure. Using isolated, perfused canine hearts, coronary perfusion pressure in the left anterior descending coronary artery (LAD) was gradually reduced in beating and non-beating conditions. Measurements were obtained with and without elevation of CS pressure to determine the mean LAD pressure-flow relationships. At normal and elevated CS pressures, the corresponding zero-flow pressures were not significantly different between the beating and non-beating hearts. A rightward shift of the mean coronary perfusion pressure-coronary flow curve for the beating heart compared to the non-beating heart was observed when CS pressure was not elevated. In contrast, the slopes for both beating and non-beating hearts were similar if the CS pressure was increased. There was a smaller increase in the mean intramyocardial pressure (IMP) at elevated CS pressures in the beating heart as compared to the non-beating heart. Moreover, the increase in diastolic IMP with increased CS pressures in the beating heart was significantly less than that in the non-beating heart. These results indicate that cardiac contraction attenuates the inhibitory effects of increased CS pressure on coronary inflow.

Cooperative interaction of NF-kappaB and C/EBP binding sites is necessary for manganese superoxide dismutase gene transcription mediated by lipopolysaccharide and interferon-gamma

Expression of the manganese superoxide dismutase (Mn-SOD) is induced by pro-inflammatory cytokines. We investigated the cis-acting elements within a tumor necrosis factor-responsive element (TNFRE) which was identified in the second intron of the murine Mn-SOD gene. Site-directed mutagenesis, reporter plasmid transfection studies and electrophoretic mobility shift assays demonstrated that inducible transcription factors enhanced the transcriptional activity of the Mn-SOD gene through the TNFRE. The cooperation between proteins binding to the newly identified NF-kappaB and C/EBP sites led to synergistic gene transcription. This report provides the first evidence that cooperation between two distinct cis-acting elements may be required for induction of Mn-SOD gene expression mediated by lipopolysaccharide and interferon-gamma.

Expression of cytokine and adhesion molecule mRNA in atherectomy specimens from patients with coronary artery disease

Coronary arteriosclerosis is an underlying condition in acute myocardial infarction (AMI), unstable angina pectoris (UAP) and stable angina pectoris (SAP), and is also related to restenosis (RS) following coronary intervention. To investigate the pathogenesis of this condition, a quantitative reverse transcriptase polymerase chain reaction was used to determine relative levels of mRNA for interleukin (IL)-1beta, IL-6, IL-8, transforming growth factor beta (TGF-beta), intercellular adhesion molecule (ICAM)-1, E-selectin and vascular cell adhesion molecule (VCAM)-1 using directional coronary atherectomy (DCA) specimens. Eleven patients with AMI, 7 with UAP, 10 with SAP and 6 with RS following a previous coronary intervention underwent DCA. The mRNA intensity for each molecule was expressed by comparing it with that of beta-actin mRNA. The AMI and UAP patients showed high frequencies of mRNA for IL-1beta, IL-8, TGF-beta, and ICAM-1 together with strong intensities of expression, whereas SAP patients showed decreased mRNA expression for these molecules. Increased IL-6 mRNA expression was observed only in AMI samples. Specimens from RS patients revealed an accumulated expression of proinflammatory cytokines, except for IL-6, as well as of TGF-beta. The study suggests that variation in mRNA expression may reflect the pathophysiology of specific types of coronary artery disease, and remodeling following vascular injury.

Detection of abnormal high-frequency components in the QRS complex by the wavelet transform in patients with idiopathic dilated cardiomyopathy

In order to investigate whether increased fine, fractionated signals within the QRS complex can detect arrhythmogenic substrates and how these fine signals link with ventricular mechanical dysfunction, wavelet analysis was performed on averaged QRS complexes obtained from the left precordial lead in 26 patients with idiopatic dilated cardiomyopathy (IDCM) and in 12 normal subjects. The number of local maxima and the duration of the wavelet transform were significantly greater in patients with IDCM than in normal subjects; the number at 100 Hz was 8.8+/-3.1 vs 6.0+/-1.1 (p<0.01), and the duration at 100Hz was 93+/-15 vs 75+/-7ms (p<0.01). Both of these indices were greater in the patients with than in those without late potentials, repetitive ventricular premature beats or cardiac death. In addition, significant inverse curvilinear relationships were observed between the left ventricular ejection fraction and both the number of local maxima and the duration of the wavelet transform. In conclusion, fine fragmented signals in the QRS complex detected by wavelet analysis would be an important marker for potentially arrhythmogenic substrates and seemed to progress in parallel with left ventricular mechanical dysfunction in IDCM.

Exercise tolerance in asymptomatic elderly men with fluoroscopically detected coronary artery calcification

STUDY OBJECTIVE

The value of detecting coronary artery calcification (CAC), by cardiac imaging, for the diagnosis of coronary artery disease (CAD) in asymptomatic middle-aged men has been demonstrated. However, the incidence of CAC increases with age. The functional significance of CAC remains unknown in asymptomatic elderly men. The purpose of this study is to explore whether CAC in asymptomatic aging men signifies the presence of cardiovascular dysfunction during exercise.

DESIGN

This study was designed to address whether elderly asymptomatic men, selected because they have CAC, have reduced exercise tolerance due to functionally significant CAD.

PARTICIPANTS AND SETTING

Thirty-eight asymptomatic male volunteers (ages 50 to 75 years, mean [+/-SD] 64+/-7 years) with a normal resting ECG and at least one coronary risk factor, in a population study. Nineteen subjects had CAC detected by digital subtraction fluoroscopy in at least two major coronary arteries, and 19 subjects had no identifiable CAC.

METHODS AND RESULTS

Each subject underwent a symptom-limited incremental exercise test with 12-lead ECG monitoring and respiratory gas analysis. Four indexes of exercise oxygen transport were evaluated: peak oxygen uptake (VO2), lactic acidosis threshold, peak VO2/heart rate ratio, and VO2 relative to a work rate increase. Eleven of 38 subjects (28%) were found to have reduced oxygen transport, which was defined as an abnormal reduction in more than two of the above four indexes of oxygen transport. Five of the 11 subjects with reduced oxygen transport had CAC, and 6 subjects did not (not significant). Only one subject with CAC had exercise ST depression.

CONCLUSION

Significant CAC in asymptomatic men over age 50 does not signify exercise limitation due to CAD.

Urinary trypsin inhibitor suppresses vascular smooth muscle contraction by inhibition of Ca2+ influx

Urinary trypsin inhibitor (UTI) and its precursor form inter-alpha trypsin inhibitor (ITI) are present in plasma. To determine the action of UTI on blood vessels, we performed isometric vascular muscle contraction tests, microcirculation studies and measurement of cytosolic free Ca2+ in vascular smooth muscle cells. An isometric vascular muscle contraction test showed that the contractions stimulated by endothelin-1 or norepinephrine were suppressed in the presence of UTI, and that the contractions were not inhibited in the presence of ITI. The microcirculation study showed that the contraction of mesenteric arterioles of WKY rats induced by norepinephrine were inhibited by treatment of UTI, and that they did not alter by treatment of ITI. Pre-incubation of UTI, but not ITI, with vascular smooth muscle cells inhibited the increase of cytosolic free Ca2+ induced by endothelin-1 or norepinephrine. Cell-binding study by biotinylated UTI showed that vascular smooth muscle cells have specific binding site for UTI, but not for ITI. We propose that circulating UTI converted from ITI has a regulatory effect on local vascular tone by regulation of Ca2+ influx into smooth muscle cells.

Morphological and functional changes in coronary vessel evoked by repeated endothelial injury in pigs

OBJECTIVE

We examined the morphological changes induced by repeated endothelial denudation in coronary artery (CA), as well as functional changes in the endothelium-dependent and smooth muscle responses to various vasoactive agents during the process of intimal thickening.

METHODS

We observed vascular responses in denuded and non-denuded portions of pig CA while being fed a normal diet (n = 11, N group) or 2% cholesterol diet (n = 25, C group) to intracoronary acetylcholine (ACh), 5-hydroxytryptamine (5-HT), substance P (SP), and isosorbide dinitrate (ISDN) with and without the nitric oxide synthesis inhibitor N omega-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg i.v.) over a period of 8 weeks. Balloon endothelial denudation of the left anterior descending CA was carried out every 2 weeks.

RESULTS

In N group, maximum vasoconstriction was obtained with ACh 2 weeks after the first denudation [26 +/- 5% vs. 1 +/- 1% pre-denudation, p < 0.05]. L-NAME did not affect ACh-induced CA diameter changes. Thereafter, the response to ACh was attenuated by repeated denudation in N groups. However, the degree of 5-HT-induced CA narrowing at the denuded portion increased from 7 +/- 4% (0 week) to 88 +/- 8% (8 weeks) (p < 0.05). The changes resulted in severe myocardial ischaemia, and suggested that endothelium-dependent vasodilation was progressively attenuated while hyperreactivity of vascular smooth muscle simultaneously increased. Vasodilation induced by SP was attenuated somewhat, but ISDN-induced vasodilation was preserved. Although mild hypercholesterolaemia was induced in C group, the vascular responses to these vasoactive agents did not differ from those of N group.

CONCLUSIONS

Repeated CA endothelial injury and regeneration induce the change of morphology and vascular reactivity in the denuded portion regardless of atherogenic diet. This study strongly suggests that intimal thickening caused by repeated endothelial injury and regeneration induces specific vascular responses to vasoactive agents. Moreover, it is also suggested that during the progression of intimal thickening, increased vascular smooth muscle contraction and decreased endothelium-dependent dilation appear in a stimulus-dependent manner, often leading to severe coronary vasoconstriction accompanied with definitive ECG ST change.

Syncope at sleep onset in a patient with nasopharyngeal carcinoma

A patient with nasopharyngeal carcinoma developed atypical parapharyngeal-lesion syncope syndrome associated with stereotypical cycles of heart rate variation, which occurred only when he was drowsy before falling asleep. Vagal tone fluctuation is implicated.

Attenuation of ischemia/reperfusion injury in rats by a caspase inhibitor

BACKGROUND

Z-Val-Ala-Asp(OMe)-CH2F (ZVAD-fmk), a tripeptide inhibitor of the caspase interleukin-1beta-converting enzyme family of cysteine proteases, may reduce myocardial reperfusion injury in vivo by attenuating cardiomyocyte apoptosis within the ischemic area at risk.

METHODS AND RESULTS

Sprague-Dawley rats were subjected to a 30-minute coronary occlusion followed by a 24-hour reperfusion. An inert vehicle (dimethylsulfoxide; group 1, n=8) or ZVAD-fmk, at a total dose of 3.3 mg/kg (group 2, n=8), was administered intravenously every 6 hours starting at 30 minutes before coronary occlusion until 24 hours of reperfusion. At this 24-hour point, hemodynamics were assessed by means of cardiac catheterization; then, the rats were killed, and the left ventricle was excised and sliced. The myocardial infarct size/ischemic area at risk and the count of presumed apoptotic cardiomyocytes (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling [TUNEL]-positive cells) within the ischemic area at risk were assessed through triphenyltetrazolium chloride staining and TUNEL methods, respectively. Peak positive left ventricular dP/dt was higher (P=.02) and left ventricular end-diastolic pressure was lower (P=.04) in group 2 than in group 1. The infarct size/ischemic area at risk of group 2 (52.4+/-4.0%) was smaller (P=.02) than that of group 1 (66.6+/-3.7%), and TUNEL-positive cells were fewer (P=.0002) (group 2, 3.1+/-0.9%; group 1, 11.1+/-1.0%). Agarose gel electrophoresis revealed DNA laddering in the border zone myocardium of group 1, but DNA ladder formation was attenuated in group 2.

CONCLUSIONS

ZVAD-fmk was effective in reducing myocardial reperfusion injury, which could at least be partially attributed to the attenuation of cardiomyocyte apoptosis.

Hypolumbarlordosis: a predisposing factor for preeclampsia

OBJECTIVE

The aim of this research was to study the relationship between lumbar lordosis and preeclampsia.

STUDY DESIGN

We studied lumbar lordosis of 52 primipara patients with pregnancy-induced hypertension and 59 normal primipara pregnant women. We determined the lumbar lordotic deviation (LLD) from lumbar lordosis measurement device in the lateral recumbent position and standing position. Roll-over test was performed for both groups. Resistance index (RI) of internal iliac artery was also measured by color Doppler sonography.

RESULTS

The LLD was 33 +/- 6.1 degrees week 20-29 and 34 +/- 6.9 degrees week 30-40, respectively. In patients with preeclampsia, the LLD was 19.8 +/- 6.3 degrees week 20-29, 21.3 +/- 7.9 degrees week 30-40. The LLD in patients with preeclampsia was significantly lower than in the normal pregnant women. The LLD correlated to the increase diastolic pressure after roll-over test significantly. Hypolumbarlordosis was frequently associated with high resistance of peripheral vessel.

CONCLUSIONS

We conclude that hypolumbarlordosis is frequently associated with preeclampsia. It is also closely related to the mechanism for positive roll-over test and increase of resistance of vessels. As lumbar lordosis does not change greatly in individuals before pregnancy, hypolumbarlordosis may be a predisposing factor for preeclampsia.

Coronary circulation in the failing heart

In congestive heart failure, vascular resistance increases because of vasoconstriction caused by activation of the neurohumoral system. On the other hand, vasodilatory responses can partially compensate for vasoconstriction by increasing vasodilatory substances. Although vasoconstrictive forces predominate as a whole, there is heterogeneity in the responses of different vascular beds to vasoactive agents. Especially, as for coronary circulation in the setting of heart failure, many factors may cause disturbances in coronary circulation. Thus, in this review, we discuss from the point of view of neurohumoral modification of coronary flow, coronary flow reserve, endothelial dependent and independent control of vasomotor tone, vascular responses in relation to vessel size or the severity of heart disease, and mechanical factors that determine coronary circulation. Throughout these discussions, the mechanism responsible for the reduction in coronary dilatory capacity is also described. Depressed myocardial blood flow and a blunted flow response to cardiovascular stimulation together may be one important mechanism responsible for the progression of disease in patients with cardiac dysfunction. Accordingly, even though it is not known whether abnormal coronary circulation is a cause or effect of heart failure, the treatment of impaired coronary flow reserve seems to be essential in the care of patients with cardiac dysfunction.

The role of chondroitin sulfate chains of urinary trypsin inhibitor in inhibition of LPS-induced increase of cytosolic free Ca2+ in HL60 cells and HUVEC cells

Preincubation of HL60 cells and HUVEC cells with urinary trypsin inhibitor (UTI) inhibited increase of cytosolic free Ca2+ induced by LPS. In contrast, an increase of cytosolic free Ca2+ induced by LPS was not inhibited by deglycosylated UTI, UTI treated with monoclonal antibody of chondroitin sulfate. 45Ca2+ binding showed that UTI binds 45Ca2+ dose-dependently. Scatchard plot analysis showed that UTI has two binding sites for Ca2+, a high affinity binding site (Kd=15 microM) and a low affinity site (Kd=150 microM), and that UTI has more than 70 Ca2+ binding sites per molecule. The Ca2+ binding capacity of deglycosylated UTI and UTI treated with monoclonal antibody of chondroitin sulfate was markedly depressed. Furthermore, UTI forms multi-polymers in the presence of Ca2+ as demonstrated by gel filtration and agarose gel electrophoresis. These results suggest that UTI is a physiological Ca2+ chelator on the cells and that the action is due to chondroitin sulfate chains of UTI.

Experimental hemolytic uremic syndrome induced by lipopolysaccharide irritation of celiac ganglia in rats

Although nervous system complications often appear in hemolytic uremic syndrome (HUS), the relationship between HUS and the nervous system is still not clear. We suspect that damage to the nervous system may play a role in the pathophysiology of HUS. In this context, rats received different doses of lipopolysaccharide (LPS) or saline to celiac ganglia or peritoneum. In rats treated with LPS on the celiac ganglia, a significant decrease in platelet count (p < 0.05) and a significant increase in blood urea nitrogen (p < 0.05) were found, and at the same time plasma levels of adrenaline and noradrenaline increased markedly (p < 0.05). The renal arterioles and glomeruli showed endothelial swelling and narrowing of the lumina. Intense immunostaining for von Willebrand factor and fibrinogen in glomeruli and renal vessels was also observed. These parameters were accompanied by a systolic blood pressure elevation. The results suggest that the sympathetic nervous system plays an important role in the pathogenesis of HUS.

Cold-induced stress stimulates the sympathetic nervous system, causing hypertension and proteinuria in rats

OBJECTIVE

To determine whether cold-stress stimulation of the soles of the paws would produce a preeclampsia-like syndrome in rats.

METHODS

Pregnant or nonpregnant rats were kept in 0 degree C floor and 23 degrees C room temperature cages (the cold-stressed group) or in 23 degrees C floor and 23 degrees C room temperature cages (the control group) for 2 weeks. Their blood pressure, proteinuria, and plasma catecholamines were measured, and histologic studies were performed on all groups.

RESULTS

There were no significant differences in systolic blood pressure between the two groups during the first week of the experimental period; however, during the last week of gestation the blood pressure of the cold-stressed group did not fall and was significantly higher than that of the control group. A significant increase in urinary protein excretion was observed in the cold-stimulated pregnant rats, in contrast to the control rats. The concentrations of norepinephrine and epinephrine in the cold-stressed pregnant rats were markedly higher than those in the control rats. A decrease in trophoblast invasion, congestion, and fibrinoid deposits of the labyrinth were observed in the cold-stressed rats. A marked increase in subendothelial fibrinoid deposits in the glomerular capillary was found only in the cold-stressed pregnant rats. The blood pressure, biochemical parameters, and histologic findings in the nonpregnant rats were almost the same as those in the pregnant rats.

CONCLUSION

Chronic local cold stimulation of the soles of the paws induces preeclampsia-like phenomena in pregnant and nonpregnant rats, and this model suggests that the cause of preeclampsia is involved in chronic stimulation of the sympathetic nerve.

A comparison of ultrastructural changes on endomyocardial biopsy specimens obtained from patients with diabetes mellitus with and without hypertension

The pathogenesis of diabetic cardiomyopathy is unknown. The synergistic, or enhanced, effect of hypertension on pathological changes in the heart of diabetic patients has been highly suspected. The purpose of this study was to evaluate the myocardial changes related to diabetes mellitus with and without hypertension, using biopsy specimens. We examined the ultrastructural changes in biopsy specimens of the endomyocardium obtained from 25 patients. They were divided into four groups: controls without hypertension or diabetes mellitus (n = 6), and patient with hypertension (n = 3), diabetes mellitus (n = 8), and diabetes with hypertension (n = 8). The diabetic patients showed nearly normal or mildly depressed systolic left ventricular function. Ultrastructural pictures were analyzed for thickening of the capillary basement membrane, presence of toluidine blue-positive materials (i.e., materials showing metachromasia) in the myocytes, size of myocytes, and interstitial fibrosis. The thickening of the capillary basement membrane, the accumulation of toluidine blue-positive materials, and interstitial fibrosis were all significantly greater in the patients with diabetes mellitus compared to the control subjects. The myocytes tended to be small (cell atrophy) in the diabetes group. Although these pathological changes in the heart were characteristic of diabetic patients, irrespective of the presence or absence of hypertension, the presence of hypertension increased the pathological changes of myocardial cells as well as abnormality in the capillary vessels in patients with diabetes mellitus. Alterations in the myocardial cells and capillaries, caused by diabetes mellitus, may lead to myocardial cell injury and interstitial fibrosis and, ultimately, to ventricular systolic and diastolic dysfunction, especially when the diabetes is accompanied by hypertension.

Effect of hypoxia and carbon monoxide on muscle oxygenation during exercise

We used near-infrared spectroscopy (NIRS) to test the hypothesis that reducing oxygen availability during exercise would affect the rate of muscle oxyhemoglobin (O2Hb) desaturation when performing work above the lactic acidosis threshold (LAT), but not below it. Seven healthy men each performed two constant work intensities (60%LAT and the LAT plus 40% of the difference between the LAT and VO2max [40%delta]) four times under the following conditions: (1) 10 min air; (2) 5 min 15%O2 + 5 min air; (3) 5 min air + 5 min 15%O2; (4) 5 min after carbon monoxide (CO) loading to increase the carboxyhemoglobin (COHb) saturation to 15%. During each test, cardiorespiratory parameters and muscle oxygenation measured with NIRS were continuously monitored. Forearm venous blood lactate was measured every 2 to 3 min. Hypoxia and CO accelerated muscle deoxygenation only for exercise above the LAT; for exercise below the LAT, neither progressive deoxygenation nor lactate accumulation occurred after initital, rapid muscle deoxygenation. The rate of decrease in muscle oxygenation between 3 to 5 min of exercise correlated with the increase in VO2 (r = 0.61, p < 0.01) and blood lactate (r = 0.70, p < 0.01) over the same period. These results support the hypothesis that progressive muscle deoxygenation occurs above the LAT and that the rate of deoxygenation is sensitive to oxygen delivery.

Mechanical stretching induces interleukin-8 gene expression in fetal membranes: a possible role for the initiation of human parturition

OBJECTIVE

Interleukin-8 (IL-8) is known to play a crucial role in human parturition. We aimed to study the effect of mechanical stretching on the expression of IL-8 in fetal membranes (amniochorion) and decidua.

STUDY DESIGN

We examined the expression of IL-8 and its receptor in fetal membranes (amniochorion) and decidua by immunohistochemical staining. Also, we studied the synthesis of IL-8 messenger RNA (mRNA) in the fetal membranes before and after stretching.

RESULTS

We found that mechanical stretching within physiological limit increased IL-8 messenger RNA (mRNA) synthesis in fetal membranes and decidua in a time- and load-dependent manner. Application of mechanical force led to markedly increased staining of IL-8 receptor in decidual cells but not in amnion or chorion cells.

CONCLUSION

These results suggested that mechanical stretching was a candidate for one of the signals important for production of IL-8 in fetal membranes and decidua and probably for initiation of a cytokine network at amniochorio-decidual interface through increased expression of IL-8 receptors.

Association between the anaerobic threshold and the break-point in the double product/work rate relationship

A break point in the double product versus work rate relationship (DPBP) during incremental exercise has previously been reported. The aim of the current study was to investigate the frequency and degree of inter-observer agreement with which a DPBP could be detected. We also wished to determine its relationship, if any, to the lactic acidosis threshold (LATla). Ten normal volunteers performed continuous incremental bicycle ergometer exercise under three different concentrations of inspired oxygen (FiO2 = 0.21, 0.15 and 0.12). In addition, a group of patients with diseases expected to result in impaired exercise tolerance performed exercise under room air conditions. Gas exchange was measured continuously and double product was measured at 15-s intervals throughout exercise using an automated sphygmomanometer. Four observers, unaware of subject identity and test condition, analysed a total of 39 tests. All four observers detected a DPBP in 29 cases (74%) and an LAT in 35 cases (90%). The intra-class correlation coefficient was 0.76 for the DPBP and 0.93 for the LATla, indicating a reasonable level of agreement among observers for both break points. The DPBP was closely related to the LATla (r = 0.865, P < 0.0001), although it occurred at a slightly higher oxygen consumption (VO2, bias 0.137 1.min-1, 95% confidence intervals 0.041-0.233). We conclude that the DPBP is a common occurrence during incremental exercise. The close relationship between the DPBP and the LATla suggests that both may reflect similar events at the level of the skeletal muscle cell.

Effects of hypoxic hypoxia on O2 uptake and heart rate kinetics during heavy exercise

It is unclear whether hypoxia alters the kinetics of O2 uptake (VO2) during heavy exercise [above the lactic acidosis threshold (LAT)] and how these alterations might be linked to the rise in blood lactate. Eight healthy volunteers performed transitions from unloaded cycling to the same absolute heavy work rate for 8 min while breathing one of three inspired O2 concentrations: 21% (room air), 15% (mild hypoxia), and 12% (moderate hypoxia). Breathing 12% O2 slowed the time constant but did not affect the amplitude of the primary rise in VO2 (period of first 2-3 min of exercise) and had no significant effect on either the time constant or the amplitude of the slow VO2 component (beginning 2-3 min into exercise). Baseline heart rate was elevated in proportion to the severity of the hypoxia, but the amplitude and kinetics of increase during exercise and in recovery were unaffected by level of inspired O2. We conclude that the predominant effect of hypoxia during heavy exercise is on the early energetics as a slowed time constant for VO2 and an additional anaerobic contribution. However, the sum total of the processes representing the slow component of VO2 is unaffected.

Effects of cardiac contraction and coronary sinus pressure elevation on collateral circulation

Controlled coronary sinus occlusion was shown to retard necrosis of ischemic myocardium. To elucidate this mechanism, regional myocardial blood flow measurement was performed with and without coronary sinus pressure elevation to 30 mmHg (CS30). Colored microspheres were injected into left and right coronary arteries after coronary perfusion of the left anterior descending (LAD) coronary artery was stopped in seven isolated canine hearts with induced atrioventricular block, either paced at 120 beats/min by direct right ventricular stimulation [beating heart (B)] or during asystole induced by stopping pacing [nonbeating heart (NB)]. Regional myocardial blood flow in the LAD perfused area in the control state in the NB with normal coronary sinus pressure (NB-CScont; 0.27 +/- 0.13 ml.min-1.g-1, means +/- SE) was significantly greater than those in B-CScont (0.19 +/- 0.09 ml.min-1.g-1; P < 0.05) and in NB with CS30 (NB-CS30; 0.19 +/- 0.09 ml.min-1.g-1; P < 0.05). Regional myocardial blood flow of the LAD area in B with CS30 (B-CS30; 0.23 +/- 0.10 ml.min-1.g-1) was significantly greater in comparison with that at B-CScont and NB-CS30 (P < 0.05). The augmentative effect of the LAD area regional myocardial blood flow was observed only in the periphery of the ischemic region but not in its center. Cardiac contraction and CS30 impede regional myocardial blood flow in the ischemic bed independently. The coexistence of these two factors enhances regional myocardial blood flow. In conclusion, coronary sinus pressure elevation in B may participate in augmenting collateral flow.

Expression of interleukin-8 receptors in the gestational tissues before and after initiation of labor: immunohistochemical study

BACKGROUND

Interleukin-8 (IL-8) has an essential role in the mechanism of parturition. IL-8 induces its effect through specific cell binding receptors. The main purpose of this research was to elucidate the presence of IL-8 receptors in the gestational tissues and their relation to parturition.

MATERIALS AND METHODS

Fetal membranes, placenta, umbilical cord and myometrial samples were collected before the initiation of labor during elective Cesarean sections (n = 15). Similar biopsies (except myometrial samples) were also gathered after normal vaginal delivery (n = 15). Immunohistochemical staining for IL-8 receptors type I and II was carried out for the fresh frozen sections of all samples. Immunoreactive score (IRS) was calculated for the stained sections.

RESULTS

IL-8 Receptors type I and II were recognized in the fetal membranes, placenta, umbilical cord and myometrial samples collected from patients before the initiation of labor. The staining of amnion and placentas were found to be more intensified in the samples collected after vaginal delivery compared to those from elective cesarean sections and before initiation of labor.

CONCLUSIONS

Increased expression of IL-8 receptors after initiation of labor may indicate that IL-8 receptors might have a role during parturition.

Urinary trypsin inhibitor: a new drug to treat preterm labor: a comparative study with ritodrine

Prevention of preterm delivery is one of the difficult problems facing obstetricians. beta Adrenergic agonists, especially ritodrine, are commonly used in these cases.

OBJECTIVES

The aim of this research was to study and compare the effect of urinary trypsin inhibitor (UTI) which has anti-inflammatory anti-cytokine effects with ritodrine in treating preterm labor.

STUDY DESIGN

Patients in preterm delivery were randomly selected to be treated either by ritodrine or UTI. In the ritodrine group, uterine contractions were initially suppressed by high doses of ritodrine (up to 300 micrograms/min) and then a maintenance dose was given until 35 weeks of gestation. In the UTI group one vaginal suppository (5000 U) was used daily for 2 weeks. Patients with recurrent preterm uterine contraction during the initial 14 days of treatment, who needed course of other drugs to suppress the contractions, were excluded from the study. Patients responding to the drugs were followed until delivery. Tocolytic index and elastase concentration in the cervical mucus was calculated. Recurrence rate of uterine contraction and time of elongation of pregnancy since the beginning of treatment was calculated.

RESULTS

UTI was more effective than ritodrine in inhibition of recurrent uterine contraction and elongation of pregnancy. No side effects could be observed after treatment with UTI for the mother or the fetus.

CONCLUSION

UTI may be a new therapeutic method for the inhibition of preterm delivery through suppression of cytokines and inflammatory mediators.

Biochemical changes in the cervical tissue of rabbit induced by interleukin-8, interleukin-1beta, dehydroepiandrosterone sulphate and prostaglandin E2: a comparative study

The aim of this research was to study and compare the mechanism of action of interleukin (IL)-8, IL-1beta dehydroepiandrosterone sulphate (DHEA-S) and prostaglandin (PG)E2 on the cervix. Five equal groups of pregnant rabbits (n = 45) were tested by either placebo or tested drugs in the form of vaginal suppositories once daily for 3 days. The suppositories contained human recombinant IL-8 (100 ng), IL-1beta (200 ng), DHEA-S (10 mg) or PGE2 (1 mg). All rabbits were tested by one dose, two doses or three doses. Consistency, dilatation and water contents were estimated 24 h after the last dose of treatment. Leukocyte infiltration of the cervices was studied after staining the cervical tissue sections with antirabbit RT2 monoclonal antibodies. Relative collagen concentration was assessed after staining with Picrosirius Red. Collagenase, gelatinase and elastase activities were measured in 100 mg of homogenized cervical connective tissue. Water contents were significantly increased in all tested cervices. Neutrophil numbers were increased in IL-8 and IL-1beta groups after the second dose of treatment (P < 0.0005 and 0.001 respectively). In the PGE2 group, neutrophils were increased after the third dose of treatment, whereas in DHEA-S group no significant changes were observed. Collagen content was significantly decreased in IL-8, IL-1beta and PGE2 groups after the first dose of treatment (P < 0.004, and 0.005 and 0.03 respectively). In the DHEA-S group, the decrease in collagen content occurred after the third dose (P < 0.05). Collagenase activity was markedly increased in IL-8, IL-1, and DHEA-S groups after the second dose of treatment (P < 0.001, 0.003 and 0.007 respectively). No significant increase in collagenase activity was found in PGE2 group. Gelatinase activity was significantly increased in IL-8, IL-1beta, PGE2 and DHEA-S groups after the second dose of treatment (P < 0.008, 0.01, 0.003 and 0.05 respectively). Also, elastase activity was increased after the second dose of treatment in all groups (P < 0.001, 0.001, 0.001 and 0.006 respectively). Our data suggest that ripening of the cervix in rabbit can be initiated by different mechanisms. Cytokines play a vital role in cervical ripening, especially IL-8 and IL-1. IL-8 is one of the factors which could ripen the cervix in a manner similar to the physiological process at term.

Induction of HELLP syndrome-like biochemical parameters by stimulation of the celiac ganglion in rats

OBJECTIVE

An animal model of HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome was developed by means of stimulation of the celiac ganglion in rats.

METHODS

The celiac ganglion in pregnant or non-pregnant rats was exposed to endotoxin (lipopolysaccharide, LPS) (500 micrograms/50 microliters), potassium chloride (0.2 mol/l/50 microliters), or saline solution (50 microliters). In another group of rats the bifurcation of the abdominal aorta was exposed to LPS (500 micrograms/50 microliters). Blood pressure, platelet count, hematocrit, serum aspartate transaminase (AST), alanine transaminase (ALT), lactate dehydrogenase (LDH), and plasma norepinephrine and epinephrine were measured for 6 h after treatment. Histopathologic studies were also performed in these rats.

RESULTS

A significant increase in blood pressure, AST, ALT, LDH, norepinephrine, and epinephrine was found in the endotoxin-treated pregnant rats compared with control rats treated with the saline solution. A significant decrease in platelet count was found in endotoxin-treated pregnant rats compared with the control rats. A significant increase in blood pressure, AST, norepinephrine, and epinephrine was found in the potassium chloride-treated pregnant rats compared with control rats. Blood pressure and biochemical parameters remained unchanged in the pregnant rats treated with LPS at the bifurcation of the abdominal aorta, as in those treated with saline at the celiac ganglion. Histologic examination of liver tissues treated with LPS or potassium chloride showed varying degrees of ischemic necrosis of hepatocytes similar to that observed in the human HELLP syndrome. Blood pressure, biochemical parameters, and histologic findings in non-pregnant rats were almost the same as those in pregnant rats.

CONCLUSION

This study suggests that exogenous stimulation of the celiac ganglion causes an increase in the blood pressure and liver ischemia, resulting in HELLP syndrome-like disease in pregnant and non-pregnant rats.

Biochemical changes in the cervical mucus after application of laminaria tent

BACKGROUND

This research was aimed to study the biochemical changes in cervical mucus after application of laminaria tent.

MATERIAL AND METHODS

Cervical mucus was collected before and after insertion of laminaria tent from 20 normal pregnant women in the first and second trimesters. Interleukin-1 beta, IL-8, collagenase activity, elastase activity, PGE2 and PGF2 alpha were measured in the collected samples. Laminaria tent was also inserted in one vaginal cervix of five non-pregnant rabbits and the clinical and histological changes were compared with five non-treated rabbits. Collagen contents were assessed histologically and Leukocyte number was counted.

RESULTS

IL-1 beta and IL-8 and elastase activity were significantly increased after insertion of laminaria (p<0.0001 and 0.001 respectively). Collagenase activity was not significantly changed. Whereas concentration of PGE2 and PGF2 alpha in the mucus were markedly increased (p<0.0001 and 0.001 respectively). Collagen contents were significantly decreased in laminaria and opposite side cervices (p<0.0001). No significant changes in leukocyte count could be observed in treated and non treated cervices.

CONCLUSIONS

Insertion of laminaria leads to increase concentration of IL-1 beta, IL-8, PGE2, PGF2 alpha and elastase activity. Mechanical stretching of the cervix and biochemical changes in cervical mucus may explain the mechanism of cervical ripening induced by laminaria.

Stretching of fetal membranes increases the concentration of interleukin-8 and collagenase activity

OBJECTIVE

The aim of this study was to determine whether stretching of fetal membranes can increase interleukin-8 concentration and collagenase activity.

STUDY DESIGN

Strips of whole fetal membranes, amnion, or muscles of the lower uterine segment were stretched for 2 or 4 hours. Interleukin-8 and collagenase activity were measured in homogenized control and stretched samples. Immunohistochemical staining for interleukin-8 was carried out.

RESULTS

The interleukin-8 concentration increased significantly after the whole fetal membranes were stretched for 2 and 4 hours (p <0.0007 and 0.001, respectively). Also, stretching of amnion and muscles of the lower uterine segment for 2 and 4 hours increased the concentration of interleukin-8 significantly (p <0.0007 after 2 and 4 hours, respectively). Collagenase activity was significantly increased after stretching of amnion, amniochorion, and muscles of the lower uterine segment for 4 hours (p <0.0007, 0.006, and 0.0007, respectively). After stretching, samples were darkly stained for interleukin-8 compared with control nonstretched samples.

CONCLUSION

Stretching of amnion, amniochorion, and muscles of the lower uterine segment increased interleukin-8 production and collagenase activity.

Immunohistological study in cases of HELLP syndrome (hemolysis, elevated liver enzymes and low platelets) and acute fatty liver of pregnancy

We immunohistologically studied the hepatic tissue sections in cases with the syndrome of hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome; n = 2) and acute fatty liver of pregnancy (AFLP; n = 2) compared to necropsy controls. Unlike in the AFLP cases, a marked infiltration of neutrophils in liver tissues was found in both cases of the HELLP syndrome. Immunostaining with the antihuman (polyclonal) TNF-alpha, IL-1 beta, IL-8 and antihuman neutrophil elastase (monoclonal antibody) was performed in paraffin-embedded hepatic tissue sections. Liver tissues in HELLP syndrome patients were stained strongly with TNF-alpha and neutrophil elastase antibody. The strongest staining pattern was observed in the eclamptic case, whereas in the AFLP cases, as in the necropsy controls, a very weak staining for anti-TNF-alpha and elastase antibody was found. The liver sections of the HELLP syndrome cases were moderately stained with polyclonal IL-1 beta and IL-8 antibodies whereas AFLP and controls had a very faint staining. Significant correlations were found between the numbers of necrotic hepatocytes and elastase dots in the same microscopic fields (randomly selected) of liver sections from two cases of HELLP syndrome (r2 = 0.63; p < 0.0001), which might suggest a neutrophil-mediated tissue damage in such a disease. This study suggests that a cytokine- and neutrophil-mediated liver injury occurs in the HELLP syndrome but not in AFLP.

Correlated plasma elastase and sera cytotoxicity in eclampsia. A possible role of endothelin-1 induced neutrophil activation in preeclampsia-eclampsia

The activation of neutrophils was studied in preeclampsia (n = 10) and eclampsia (n = 20) compared to normotensive controls (n = 10) and nonpregnant essential hypertensives (n = 10). Plasma elastase levels were raised in preeclampsia (0.53 +/- 0.32 microgram/mL, P < .002) and eclampsia (1.26 +/- 0.8 microgram/mL, P < .001) respectively compared to normal pregnancies (0.032 +/- 0.009 microgram/mL). The plasma elastases were more elevated in eclamptic cases compared to essential hypertensive (0.53 +/- 0.27 microgram/mL; P = .01) patients. We analyzed the correlation among elastase values, systolic (SBP), mean blood pressures (MBP), endothelin-1 (ET-1) levels and sera cytotoxicity (as measured by fura-2 release from human umbilical venous endothelial cell culture) in eclamptic cases. SBP and MBP were significantly correlated with plasma elastase levels in preeclampsia (r = 0.67, 0.63, respectively; P < .03) and eclampsia (r = 0.49, 0.49, respectively; P < .02). ET-1 levels were correlated with SBP (P = .003) and MBP (P = .001) and corresponding elastase levels (r = 0.606, P < .003) in eclamptic patients. Doses of 10, 25, and 50 pmol/mL of ET-1 increased elastase release in human neutrophil cultures dose and time dependently. Cytotoxicity of eclamptic sera correlated (P < .001) to the corresponding plasma elastase values. Therefore, this study suggests that neutrophil activation and ET-1 induced neutrophil activation occurs in this disease.

Effects of urinary trypsin inhibitor on myometrial contraction in term and preterm deliveries

The aim of this research was to study the concentration of urinary trypsin inhibitor in amniotic fluid (AF) and its effect on myometrial contraction in term and preterm deliveries. Urinary trypsin inhibitor was measured in AF of term and preterm labor. Immunohistochemical staining of amnion and myometrium was carried out. Isometric uterine contraction was studied to elucidate the effect of AF and urinary trypsin inhibitor on the contractile activity of term and preterm myometrium. The effect of urinary trypsin inhibitor on the production of prostaglandin E2 (PGE2) from myometrial cultures stimulated by IL-8, IL-1 and LPS was verified. Urinary trypsin inhibitor was significantly increased in AF of cases of preterm delivery (p < 0.0001). Amnion and myometrium of preterm deliveries were faintly stained for urinary trypsin inhibitor compared to term delivery. Amniotic fluid and urinary trypsin inhibitor could successfully inhibit-myometrial contraction. Also, urinary trypsin inhibitor could significantly inhibit the production of PGE2 in the myometrial cell cultures stimulated by IL-1 and LPS (p < 0.001 and 0.0005). IL-8 has no significant effect on PGE2 production from myometrial cell culture. Urinary trypsin inhibitor suppresses myometrial contraction in term and preterm deliveries. It may play a role in maintaining normal pregnancy and preventing preterm delivery.