An HMG-CoA reductase inhibitor, cerivastatin, suppresses growth of macrophages expressing matrix metalloproteinases and tissue factor in vivo and in vitro

BACKGROUND

Unstable atherosclerotic plaques that cause acute coronary events usually contain abundant macrophages expressing matrix metalloproteinases (MMPs) and tissue factor (TF), molecules that probably contribute to plaque rupture and subsequent thrombus formation. Lipid lowering with HMG-CoA reductase inhibitors reduces acute coronary events.

METHODS AND RESULTS

To test whether lipid lowering with an HMG-CoA reductase inhibitor retards macrophage accumulation in rabbit atheroma, we administered cerivastatin to immature Watanabe heritable hyperlipidemic rabbits (cerivastatin group, n=10, cerivastatin 0.6 mg x kg(-1) x d(-1); control group, n=9, saline 0.6 mL x kg(-1) x d(-1)) for 32 weeks and measured macrophage accumulation and expression of MMPs and TF. Serum cholesterol levels after 32 weeks were 809+/-40 mg/dL (control group) and 481+/-24 mg/dL (treated group). Cerivastatin diminished accumulation of macrophages in aortic atheroma. Macrophage expression of MMP-1, MMP-3, MMP-9, and TF also decreased with cerivastatin treatment. Cerivastatin reduced the number of macrophages expressing histone mRNA (a sensitive marker of cell proliferation) detected by in situ hybridization but did not alter macrophages bearing a marker of death (TUNEL staining). Cerivastatin treatment (>or=0.01 micromol/L) also reduced growth, proteolytic activity due to MMP-9, and TF expression in cultured human monocyte/macrophages.

CONCLUSIONS

These results suggest that lipid lowering with HMG-CoA reductase inhibitors alters plaque biology by reducing proliferation and activation of macrophages, prominent sources of molecules responsible for plaque instability and thrombogenicity.

Adenosine-induced coronary flow reserve in Watanabe heritable hyperlipidemic rabbits

The Watanabe heritable hyperlipidemic (WHHL) rabbit develops coronary atherosclerosis and hypercholesterolemia because of a genetic deficiency of low-density lipoprotein receptors and is therefore a good animal model for studying the relationships of coronary atherosclerosis, hypercholesterolemia and coronary flow reserve. The aim of the present study was to assess myocardial perfusion at baseline and during adenosine infusion (0.2 mg x kg(-1) x min(-1)) in 8 WHHL rabbits (13.8+/-0.5 months) with 13N-ammonia, small-animal positron emission tomography (PET) and colored microspheres. Results were compared with those from 6 age-matched Japanese white rabbits. Plaque distribution was also examined in the extramural coronary arteries. All 8 WHHL rabbits had coronary plaques, with 6 showing multiple plaques. Mean global myocardial blood flow (ml x min(-1) x g(-1)) did not differ significantly between control and WHHL groups both at baseline (3.67+/-0.72 vs 4.26+/-1.12 ml x min(-1) x g(-1), p=NS) and with adenosine (7.92+/-2.00 vs 9.27+/-2.91 ml x min(-1) x g(-1), p=NS), nor did coronary flow reserve (2.16+/-0.37 vs 2.18+/-0.41, p=NS). None showed evidence of regional perfusion abnormalities by visual and semiquantitative analyses of PET images. It was concluded that WHHL rabbits preserve adenosine-induced coronary flow reserve despite coronary atherosclerosis and hypercholesterolemia, suggesting that a compensatory mechanism develops in this animal model.

Comparison of endothelium-dependent relaxation in carotid arteries from Japanese white and Watanabe heritable hyperlipidemic rabbits

Modifications by atherosclerosis of endothelium-dependent and -independent relaxations were evaluated in carotid arteries isolated from Watanabe heritable hyperlipidemic (WHHL; age 20-29 months) and age-matched Japanese white (JW) rabbits. Marked, patchy atherosclerotic lesions were observed in all WHHL rabbit arteries. Endothelium-dependent relaxations induced by acetylcholine, partly depressed by N(G)-nitro-L-arginine (L-NA), were significantly inhibited in the WHHL rabbit arteries with atherosclerosis, compared with those in the arteries without atherosclerotic lesions from JW and WHHL rabbits. No difference was observed in the relaxation caused by superoxide dismutase in these arteries. Conversely, endothelium-dependent relaxations by substance P were greater in the arteries with and without atherosclerosis from WHHL rabbits than in the arteries from JW rabbits. Endothelium-independent relaxations elicited by sodium nitroprusside and 2,2-(hydroxynitrosohydrazino)bis-ethanamine (NOC18) did not differ in the arteries from JW and WHHL rabbits. The responses to acetylcholine and substance P of JW rabbit arteries with the endothelium were not attenuated by treatment with pertussis toxin. L-NA-resistant, endothelium-dependent relaxations by substance P were almost abolished by charybdotoxin, and atherosclerosis did not alter the response. It is concluded that endothelial functions, evaluated by substance P, in rabbit carotid arteries are not impaired by atherosclerosis and by long exposure to hyperlipidemia in vivo. Dysfunction of muscarinic receptors may be involved in the depressed response to acetylcholine. As far as the arteries used in the present study are concerned, responses mediated possibly by endothelium-derived hyperpolarizing factor (EDHF) are unlikely to be modulated by atherosclerosis.

[1-11C]Octanoate as a PET tracer for studying ischemic stroke: evaluation in a canine model of thromboembolic stroke with positron emission tomography

Octanoate is taken up by the brain and converted in astrocytes to glutamine through the TCA cycle after beta-oxidation. Consequently, [1-11C]octanoate might serve as a useful positron emission tomography (PET) probe for studying cerebral oxidative metabolism and/or astroglial functions. The present study attempted to evaluate the utility of using [1-11C]octanoate as a PET tracer for imaging and evaluating the pathophysiology of ischemic stroke. We used a canine model of thromboembolic stroke. Five male beagle dogs were implanted with an indwelling catheter in the left internal carotid artery. A single autologous blood clot was injected into the left internal carotid artery through the catheter. The brain distribution of [1-11C]octanoate and cerebral blood flow (CBF) were determined 24 h after insult using a high resolution PET scanner. Post mortem brain regions unstained with 2,3,5-triphenyltetrazolium chloride (TTC) were defined as infarcts. In the region of an infarct, accumulation of [1-11C]octanoate decreased concurrently with CBF reduction. In contrast, normal accumulation of [1-11C]octanoate was observed in ischemic but vital regions, suggesting that an increased accumulation of [1-11C]octanoate relative to CBF takes place in these regions. In conclusion, [1-11C]octanoate accumulated in ischemic but vital regions, indicating that [1-11C]octanoate is a potentially useful PET tracer for imaging and evaluating the pathophysiology of ischemic stroke.

Defects of the LDL receptor in WHHL transgenic rabbits lead to a marked accumulation of plasma lipoprotein[a]

In this study, we created LDL receptor (LDLr) defective (WHHL) transgenic rabbits expressing human apo[a] to examine whether LDLr mediates the Lp[a] clearance from the plasma. By crossbreeding WHHL rabbits with human apo[a] transgenic rabbits, we obtained two groups of human apo[a] transgenic rabbits with defective LDLr functions: apo[a](1/0) WHHL heterozygous (LDLr(+/-) and apo[a](+/0) WHHL homozygous (LDLr(-/-) rabbits. The lipid and lipoprotein levels of human apo[a] WHHL rabbits were compared to those of human apo[a] transgenic rabbits with normal LDLr functions (LDLr(+/+). The apo[a] production rate was evaluated by analyzing apo[a] mRNA expression in the liver, the major site for apo[a] synthesis in transgenic rabbits. We found that pre-beta lipoproteins were markedly increased accompanied by a 2-fold increase in the plasma Lp[a] in apo[a](+/0)/LDLr(+/-) rabbits and a 4.2-fold increase in apo[a](+/0)/LDLr(-/-) rabbits compared with that in apo[a](+/0) rabbits with normal LDLr function. In apo[a](+/0)/LDLr(-/-) rabbits, there was a marked increase in plasma total cholesterol and triglycerides, as was found in their counterpart non-transgenic WHHL rabbits. Northern blot analysis revealed that hepatic apo[a] expression in WHHL transgenic rabbits was similar to that in LDLr(+/+) transgenic rabbits, suggesting the accumulation of plasma Lp[a] in WHHL transgenic rabbits was not due to increased apo[a] synthesis. In conclusion, absence of a functional LDLr leads to a marked accumulation of plasma Lp[a] in human apo[a] transgenic WHHL rabbits and LDLr may participate in the catabolism of Lp[a] in rabbits.

Age-associated decrease in plasma cholesterol and changes in cholesterol metabolism in homozygous Watanabe heritable hyperlipidemic rabbits

We examined the cholesterol metabolism of homozygous Watanabe heritable hyperlipidemic (WHHL) rabbits, an animal model deficient in low-density lipoprotein (LDL) receptors, to clarify the mechanism of the age-associated decrease of plasma total cholesterol, one of the properties of WHHL rabbits. The rabbits were examined at several ages: after weaning at 3 months, at sexual maturation at 6 months, at 12 months, and at 24 months, equivalent to about 35 years of age in humans. Plasma total cholesterol, triglyceride, and phospholipid levels decreased with aging by about 45%. These reductions were mainly dependent on a decrease in the LDL fraction. In the liver microsomal fraction, although there were no age-related changes in the cholesterol concentration and cholesterol 7alpha-hydroxylase (C7H) activity, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity increased and acyl-coenzyme A:cholesterol acyltransferase (ACAT) activity decreased with aging. The lipolytic activity varied with aging. The secretion rate of very-low-density lipoprotein (VLDL) cholesterol as determined by injection of Triton WR-1339 decreased significantly with aging, while the catabolic rate of VLDL cholesterol was about 2-fold higher in the oldest group versus the young groups. From these results, we conclude that the age-associated decrease in plasma cholesterol in WHHL rabbits is related not only to a decrease in the secretion rate of VLDL cholesterol but also to an increase in the catabolic rate.

Preliminary evaluation of [1-11C]octanoate as a PET tracer for studying cerebral ischemia: a PET study in rat and canine models of focal cerebral ischemia

Octanoate is taken up into the brain and is converted in astrocytes to glutamine through the TCA cycle after beta-oxidation. We speculate that [1-11C]octanoate may be used as a tracer for astroglial functions and/or fatty acid metabolism in the brain and may be useful for studying cerebral ischemia. In the present study we investigated brain distribution of [1-11C]octanoate and compared it with cerebral blood flow (CBF) by using rat and canine models of middle cerebral artery (MCA) occlusion and a high resolution PET. In rats brain distribution of [15O]H2O measured 1-2 h and 5-6 h after insult was compared with that of [1-11C]octanoate measured 3-4 h after insult. Radioactivity ratios of lesioned to normal hemispheres determined with [15O]H2O were lower than those determined with [1-11C]octanoate. These results were confirmed by a study on a canine model of MCA-occlusion. Twenty-four hours after insult, CBF decreased in the MCA-territory of the occluded hemisphere, whereas normal or higher accumulation of [1-11C]octanoate was observed in the ischemic regions. The uptake of [1-11C]octanoate-derived radioactivity therefore increased relative to CBF in the ischemic regions, indicating that [1-11C]octanoate provides functional information different from CBF. In conclusion, we found that [1-11C]octanoate is a potential radiopharmaceutical for studying the pathophysiology of cerebral ischemia.

Exacerbation of herpes simplex encephalitis after successful treatment with acyclovir

Herpes simplex encephalitis (HSE) in children sometimes exacerbates after successful treatment; yet the frequency, etiology, and clinical features of exacerbation remain unclear. We report data for 27 children with HSE confirmed by polymerase chain reaction (PCR) analysis; all were successfully treated with acyclovir, but 7 (26%) had a relapse of encephalitic illness. In 2 of those 7, serial examination with a PCR assay showed that herpes simplex virus (HSV) DNA reappeared temporarily in the cerebrospinal fluid (CSF). For 5 of the 7 patients, a second course of acyclovir therapy was effective. Coxsackievirus A9 was isolated from CSF of 1 case patient during subsequent exacerbation. The total dose during initial acyclovir therapy was significantly lower in the relapse group than in the control group (P=.027). In conclusion, exacerbation of HSE in children may be more common than previously recognized. It is suggested that the replication of HSV or another viral pathogen caused a second encephalitic illness (HSE) in some cases.

Radioprotective effects of sodium tungstate on hematopoietic injury by exposure to 60Co gamma-rays in Wistar rats

Radioprotective effects of sodium tungstate (ST) on 60Co gamma-ray induced decrease in hematocrit value and in survival rate in Wistar strain male rats were examined. A long-term administration of ST (less than 150 mg/kg body weight/day) for 60-300 days had no significant effects on body and organs weights and survival days. The LD50/60 in 20 weeks old rats was 220 mg/kg body weight/day. Daily administration of 38, 75 or 150 mg from 7 days before and after irradiation to 60 days significantly mitigated the decrease in hematocrit values, especially at 23 days after irradiation (P < 0.05). The highest mitigation rate of the decrease in hematocrit value was observed in rats administered at a dose of 38 mg ST/day. Simultaneously, a dose of 38 mg ST/day inhibited lethal effect of 60Co gamma-rays significantly. The dose-reduction factor for survival of 38 mg ST administered rats was 1.14.

Granulocyte-macrophage colony-stimulating factor prevents the progression of atherosclerosis via changes in the cellular and extracellular composition of atherosclerotic lesions in watanabe heritable hyperlipidemic rabbits

BACKGROUND

A cytokine network is involved in atherogenesis. This study was conducted to investigate the effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) on the development and composition of atherosclerotic lesions in Watanabe heritable hyperlipidemic (WHHL) rabbits.

METHODS AND RESULTS

GM-CSF (10 microg. kg-1. d-1) was administered to 4-month-old WHHL rabbits (n=9) 5 days a week for 7.5 months, whereas an equal dose of human serum albumin was administered to controls (n=9). The cholesterol levels were not changed significantly by the treatment. Age-matched 4-month-old rabbits (n=7) had atheromatous plaques over 30.7+/-5.7% of the inner surface area of the aortic arch. After treatment, the percentages of surface atheromatous plaques to total aortic arch area were 45.0+/-12.6% in the GM-CSF group and 74.3+/-11.0% in controls (P<0.0001). Histological examination demonstrated that GM-CSF reduced the ratio of intima to media (P<0.01) and cross-sectional areas of atherosclerotic lesions (P<0.0001). Quantitative analysis indicated a marked decrease in the areas of smooth muscle cells (P=0.0001), collagen (P=0.0001), and extracellular lipid deposits (P<0.05) of atheromatous plaques in GM-CSF-treated rabbits compared with controls. The terminal deoxynucleotidyltransferase-mediated dUTP-digoxigenin nick end-labeling (TUNEL) method and immunohistochemistry were performed to examine the relationship between decreased atherosclerotic lesions and apoptosis. The percentage of TUNEL-positive cells increased in the GM-CSF group (GM-CSF, 24.1+/-4.4% versus control, 11.6+/-3.2%; P<0.0001). GM-CSF enhanced the apoptosis of smooth muscle cells in the shoulder region and the fibrous cap (P<0.0001), suggesting one of the mechanisms for the antiatherogenic effect.

CONCLUSIONS

GM-CSF altered the composition of atherosclerotic lesions and reduced the atherosclerosis in WHHL rabbits.

Effect of early oral fluoroquinolones in hemorrhagic colitis due to Escherichia coli O157:H7

During the Sakai outbreak of Escherichia coli O157:H7 infection, which was linked to contaminated cafeteria school lunches, there were several treatment modalities with regard to antimicrobial drugs. Patient outcomes among three hospitals with different modalities were compared retrospectively. Hemolytic uremic syndrome did not develop in any of the 15 patients treated with oral fluoroquinolone therapy; however, HUS did develop in three of 15 patients treated with intravenous (i.v.) fosfomycin and in two of 12 patients treated with i.v. cefotaxime and oral fosfomycin. The results indicate that oral fluoroquinolone therapy administered within 3 days of illness is effective in preventing the development of HUS; however, prospective randomized double-blind studies on early antimicrobial therapy of O157 hemorrhagic colitis are necessary. Several antibiotics, including fluoroquinolones, were reported to induce the production or release of Shiga-like toxins (STX) from E. coli O157:H7 in vitro. Although patients were examined for fecal STX, no STX were detected in the stools of patients treated with oral fluoroquinolones. In fact, treatment with fluoroquinolones for 5 days eradicated E. coli O157 in all patients.

Combination treatment with troglitazone, an insulin action enhancer, and pravastatin, an inhibitor of HMG-CoA reductase, shows a synergistic effect on atherosclerosis of WHHL rabbits

We examined whether improving insulin resistance augments the antiatherosclerotic effect of LDL reduction. Since WHHL rabbits show hyperinsulinemia and insulin resistance, we administered troglitazone (100 mg/kg), an insulin action enhancer, pravastatin sodium (50 mg/kg), an HMG CoA reductase inhibitor, and a combination of both drugs to 2-month-old WHHL rabbits for 32 weeks. As compared to the control, total cholesterol levels in the plasma and LDL were decreased significantly by 20% in the pravastatin and combination groups. Basal immunoreactive insulin levels and insulin index were decreased significantly by approximately 50% in the troglitazone and combination groups. Surface lesion area of atherosclerosis on the thoracic aorta was decreased significantly by 36% in the combination group and was less in the troglitazone group. Coronary atherosclerosis was decreased significantly by 39% in the combination group and was less in the pravastatin and troglitazone groups. The collagen content in the plaques was decreased in the troglitezone and combination groups and the extracellular lipid deposits were decreased in the pravastatin and combination groups. The incidence and severity of xanthomata in the digital joints were also decreased significantly in the three treated groups. In conclusion, the antiatherogenic effect of the combination treatment is stronger than that of the monotherapy.

Neopterin Concentrations of Serum and Cerebrospinal Fluid in Febrile Convulsion, Aseptic Meningitis and Influenza Encephalopathy

The concentration of total neopterin in serum and cerebrospinal fluid (CSF) was measured in cases of febrile convulsion, aseptic meningitis and influenza encephalopathy. In febrile convulsion except for exanthem subitum, the concentrations of CSF neopterin (26± 11, Mean±SD, n=6) were all within normal range while those of serum neopterin (66± 20, n=8) were significantly higher (p < 0.05). In aseptic meningitis, on the other hand, the concentrations of CSF neopterin (194± 130, n=13) were significantly higher than those of serum (33±23, n=11, p < 0.05). In influenza encephalopathy, both concentrations of serum neopterin (329±478, n=13) and CSF neopterin(179±131, n=11) were much higher than the control range. Our results indicate that the primary immunoreacting site is the central nervous system (CNS) for aseptic meningitis, the periphery for febrile convulsion except for exanthem subitum and both the periphery and the CNS for influenza encephalopathy. Measurements of neopterin concentrations in CSF as well as in serum may thus constitute an immediate aid for early differentiation of CNS infection from peripheral infection as well as for early detection of viral encephalopathy caused by viruses such as the influenza virus or the human herpes virus 6.

Effect of cerivastatin sodium, a new inhibitor of HMG-CoA reductase, on plasma lipid levels, progression of atherosclerosis, and the lesional composition in the plaques of WHHL rabbits

1. The aim of this study was to examine whether cerivastatin sodium, a new inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, affects the lesional composition of spontaneously developed atherosclerosis due to hypercholesterolaemia and delays progression of the lesions. 2. We administered cerivastatin to 2-month-old WHHL rabbits, a low-density lipoprotein receptor-deficient animal model, at a dose of 0.6 mg kg(-1) day(-1) for 32 weeks. We examined the plasma lipid levels, the severity of atherosclerosis, and composition of atherosclerotic lesions. Lesional composition was determined using immunohistostaining for macrophages and smooth muscle cells, and Azan-Mallory staining for collagen fibres and extracellular lipid deposits. 3. Compared to the control group, the plasma cholesterol levels were decreased in the treated group by 39% (12.7+/-0.6 mmol L(-1) versus 20.9+/-1.0 mmol L(-1), P<0.001). Atherosclerosis was suppressed by about 37% as measured by the thickness of the aortic lesions (158+/-13 microm versus 250+/-15 microm, P<0.001), and by 28% as measured by coronary stenosis (62.7+/-11.4 versus 86.9+/-12.2, P<0.05). In the cerivastatin group, regarding the per cent areas of lesional components in the lesion area, the macrophages (21.0+/-1.5% versus 27.9+/-1.9%, P<0.01) and extracellular lipid deposits (3.2+/-0.4% versus 5.1+/-0.4%, P<0.001) were decreased in the aortic lesions, and the per cent area of macrophages in the coronary lesions was also decreased (4.9+/-1.4% versus, 11.6+/-2.4%. P<0.05). The per cent area of smooth muscle cells and collagen fibres did not significantly decrease. 4. These results indicate that cerivastatin contributed to the plaque stabilization and delayed progression of early atherosclerosis in young WHHL rabbits, in addition to the potent hypolipidemic effects.

An additional variant of the persistent primitive trigeminal artery: accessory meningeal artery--antero-superior cerebellar artery anastomosis associated with moyamoya disease

Persistent embryological carotid-basilar anastomoses are rare. There has been no report on persistent anastomosis between the accessory meningeal artery and the antero-superior cerebellar artery. We describe a 3-year-old boy with moyamoya disease manifesting such a congenital vascular anomaly, namely, a large anastomosis between the accessory meningeal artery and the antero-superior cerebellar artery associated with marked hypoplasia of the basilar artery. This persistent vascular anomaly is considered embryologically as an additional variant of the persistent primitive trigeminal artery, i.e., a "stapedo-trigemino-cerebellar" variant.

Morphological Study of Carotid Artery of WHHL Rabbit after Balloon Dilatation

SUMMARY

We performed balloon dilatation in the carotid artery of WHHL rabbits and examined subsequent morphological alteration over time. The balloon was inserted as far as the carotid bifurcation and observations were made on the morphological alteration after dilatation in the atherosclerotic intimal thickening from immediately after balloon dilatation over a period of ten months. Immediately after balloon dilatation, endothelial cells came of circularly and stretching, fragmentation off elastic fibers and coming off of smooth muscle cells of the media were confirmed. No change in the degree of thickening after dilatation was seen in the atherosclerotic intimal thickening of the carotid bifurcation. Three weeks later, endothelium covering except some parts, circular neointima and fibrosis of the media were observed; foamy cells had accumulated in the upper layer of the atherosclerotic intimal thickening, and that region was not yet covered with endothelial cells. The progress of fibrous intimal thickening so as to keep the lumen smooth was seen up to six months later, but foamy cells were not found in the neointima.

Encephalopathy and cytomegalovirus colitis in an AIDS child

A 2-year-old girl, who had prolonged thrush and spastic diplegia, was found to have a mother-to-child vertical transmission of human immunodeficiency virus type-1 (HIV). A brain computed tomography scan revealed a symmetrical calcification on the bilateral basal ganglia and periventricular white matter. She had an acquired immune deficiency syndrome (AIDS) encephalopathy of pure dominant pyramidal tract disorder without an intellectual deficit. Helper cell lymphocyte count (CD4) increased with the beginning of zidovudine (ZDV, also known as AZT) monotherapy but began to decrease after the 4th week to reach the baseline at 20th week. Zidovudine plus didanosine combination therapy was started at the 68th week, but because of intolerance, the combination was changed to ZDV plus lamivudine at the 98th week. By the 80th week, neither severe opportunistic infection nor deterioration of the neurological status was recognized, but chronic diarrhea appeared. The diarrhea advanced to the wasting syndrome at the age of 4 years and cytomegalovirus genome was confirmed in a biopsied specimen of the colon. Ganciclovir treatment was effective in stopping the diarrhea and increasing her bodyweight, but after the age of 5, resumption of diarrhea was followed by progressive emaciation and weakness. This work may provide some clues in treating children's AIDS.

[Application of a semi-automatic ROI setting system for brain PET images to animal PET studies]

ProASSIST, a semi-automatic ROI (region of interest) setting system for human brain PET images, has been modified for use with the canine brain, and the performance of the obtained system was evaluated by comparing the operational simplicity for ROI setting and the consistency of ROI values obtained with those by a conventional manual procedure. Namely, we created segment maps for the canine brain by making reference to the coronal section atlas of the canine brain by Lim et al., and incorporated them into the ProASSIST system. For the performance test, CBF (cerebral blood flow) and CMRglc (cerebral metabolic rate in glucose) images in dogs with or without focal cerebral ischemia were used. In ProASSIST, brain contours were defined semiautomatically. In the ROI analysis of the test image, manual modification of the contour was necessary in half cases examined (8/16). However, the operation was rather simple so that the operation time per one brain section was significantly shorter than that in the manual operation. The ROI values determined by the system were comparable with those by the manual procedure, confirming the applicability of the system to these animal studies. The use of the system like the present one would also merit the more objective data acquisition for the quantitative ROI analysis, because no manual procedure except for some specifications of the anatomical features is required for ROI setting.

Effect of fluvastatin sodium on the smooth muscle cells in atherosclerotic plaques. In vivo study using low-density lipoprotein receptor deficient Watanabe heritable hyperlipidemic (WHHL) rabbits

The effects of fluvastatin sodium (CAS 93957-55-2, XU 62-320), an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on the smooth muscle cells in the atherosclerotic plaques of Watanabe heritable hyperlipidemic (WHHL) rabbits, a low density lipoprotein (LDL) receptor deficient animal model, were examined. Fluvastatin was administered to WHHL rabbits for 32 weeks at a dose of 50 mg/kg of body weight. The control WHHL rabbits were administered distilled water as placebo. Compared to the control group, the total cholesterol levels in the sera, very low density lipoprotein, intermediate density lipoprotein, and LDL decreased by 34%, 72%, 63%, and 25%, respectively. Although the surface lesion area of the aorta in the treated group was not different from that in the control group, intimal thickening in the treated group was significantly lower than that in the control group. Of the lesional components of atherosclerosis, the relative area of smooth muscle cells, collagen fibers, and extracellular lipid deposits in the treated group decreased significantly. It is concluded that fluvastatin decreased in the smooth muscle cell content of the atherosclerotic plaques and delayed progression of the aortic atherosclerosis in addition to the potent hyperlipidemic effect.

Nitric oxide suppression reversibly attenuates mitochondrial dysfunction and cholestasis in endotoxemic rat liver

This study aimed to examine whether nitric oxide (NO) plays a causal role in endotoxin-induced dysfunction of biliary transport. Rats were treated with intraperitoneal injection of endotoxin (O111B4, 4 mg/kg). At 2 hours, the liver was excised and perfused ex vivo with taurocholate (TC)-containing Krebs-Ringer solution under monitoring bile output and NO2 in the perfusate and tissue cyclic guanosine monophosphate (cGMP) levels as indices of NO production. The endotoxin treatment evoked a marked decrease in the bile acid-dependent bile formation concurrent with the increasing NO2 output, cGMP elevation, and a reduction of hepatic adenosine triphosphate (ATP) contents and oxygen consumption. Perfusion with 1 mmol/L aminoguanidine (AG), an inhibitor of inducible NO synthase, but not with L-nitroarginine methyl ester, an inhibitor of the constitutive form of the enzyme, significantly reversed the endotoxin-induced increment of the bile formation in concert with the recovery of oxygen consumption and ATP levels. Laser confocal microfluorography of the liver lobules using rhodamine 123 (Rh), a fluoroprobe sensitive to mitochondrial membrane potential, revealed that endotoxin elicited a significant mitochondrial dysfunction panlobularly. The AG administration reversed the endotoxin-induced decrease in mitochondrial membrane potential. Collectively, up-regulation of NO by inducible NO synthase accounts for a mechanism through which endotoxin impairs the bile formation, and its suppression serves as a therapeutic strategy for improvement of hepatobiliary function.