Characteristics of the glycometabolic categories based on the oral glucose tolerance test results in Japanese adults without diabetes.

OBJECTIVE: We aimed to classify Japanese adults without diabetes into different categories based on the oral glucose tolerance test (OGTT) and characterize their insulin sensitivity and insulin secretion. PATIENTS AND METHODS: The OGTT was performed on 1,085 Japanese individuals without diabetes (aged 20-64 years); blood glucose and insulin levels were measured at 0, 30-, 60-, 90-, and 120-min. Fasting blood chemistry, hematology, and urine were analyzed. The participants were classified into four categories based on the following: (A) 30 min post-load plasma glucose levels < 157 mg/dL and/or (B) 120 min post-load plasma glucose levels < 126 mg/dL and Matsuda index > 4.97. Category 1 satisfied both conditions, category 2 satisfied condition A but not B, category 3 satisfied condition B but not A, and category 4 satisfied neither condition. RESULTS: Overall, 46%, 21%, 13%, and 20% of the participants were classified into categories 1, 2, 3, and 4, respectively. Compared with category 1, the characteristics of the other categories were: 2, low insulin sensitivity and high blood glucose levels during the later period; 3, low insulin secretion and a rapid increase in blood glucose levels; and 4, combined characteristics of categories 2 and 3. Most blood test values besides glucose metabolism in category 4 were also worse than those in category 1. Categories 1 and 2 had a high proportion of females, whereas categories 3 and 4 had a low proportion. CONCLUSIONS: Japanese adults without diabetes are classified into four categories with different insulin sensitivities and insulin secretion using OGTT results. Each category has different characteristics of age and sex distribution and clinical values besides glucose metabolism.

Cholesterol 25-hydroxylase is a metabolic switch to constrain T cell-mediated inflammation in the skin.

Interleukin-27 (IL-27) is an immunoregulatory cytokine whose essential function is to limit immune responses. We found that the gene encoding cholesterol 25-hydroxylase (Ch25h) was induced in CD4+ T cells by IL-27, enhanced by transforming growth factor­ß (TGF-ß), and antagonized by T-bet. Ch25h catalyzes cholesterol to generate 25-hydroxycholesterol (25OHC), which was subsequently released to the cellular milieu, functioning as a modulator of T cell response. Extracellular 25OHC suppressed cholesterol biosynthesis in T cells, inhibited cell growth, and induced nutrient deprivation cell death without releasing high-mobility group box 1 (HMGB1). This growth inhibitory effect was specific to actively proliferating cells with high cholesterol demand and was reversed when extracellular cholesterol was replenished. Ch25h-expressing CD4+ T cells that received IL-27 and TGF-ß signals became refractory to 25OHC-mediated growth inhibition in vitro. Nonetheless, IL-27­treated T cells negatively affected viability of bystander cells in a paracrine manner, but only if the bystander cells were in the early phases of activation. In mouse models of skin inflammation due to autoreactive T cells or chemically induced hypersensitivity, genetic deletion of Ch25h or Il27ra led to worse outcomes. Thus, Ch25h is an immunoregulatory metabolic switch induced by IL-27 and dampens excess bystander T effector expansion in tissues through its metabolite derivative, 25OHC. This study reveals regulation of cholesterol metabolism as a modality for controlling tissue inflammation and thus represents a mechanism underlying T cell immunoregulatory functions.

Acute CO2-independent vasodilatation of penetrating and pre-capillary arterioles in mouse cerebral parenchyma upon hypoxia revealed by a thinned-skull window method.

AIM: Investigating spatio-temporal relationship between regional metabolic changes and microvascular responses in hypoxic brain is critical for unravelling local O(2) -sensing mechanisms. However, no reliable method to examine the relationship has been available because of inherent disadvantages associated with use of a conventional cranial window preparation. We aimed to devise a method to solve the problem. METHODS: Anaesthetized mice were equipped with either a conventional cranial window with craniotomy or a thinned-skull preparation. Mice were mechanically ventilated to avoid hypercapnia and exposed to systemic isobaric hypoxia for 30 min. Using two-photon laser scanning microscopy, nicotinamide adenine dinucleotide, reduced form (NADH) autofluorescence and diameter changes in penetrating and pre-capillary arterioles within the parenchyma were visualized to examine their temporal alterations. RESULTS: With the conventional cranial window preparation, marked vertical displacement of the tissue occurred through oedema within 30 s after inducing hypoxia. With a thinned-skull preparation, however, such hypoxia-induced displacement was diminished, enabling us to examine acute spatio-temporal changes in diameters of penetrating and pre-capillary arterioles and NADH autofluorescence. Vasodilatation of these microvessels was evoked within 1 min after hypoxia, and sustained during the entire observation period despite the absence of hypercapnia. This event coincided with parenchymal NADH elevation, but the onset and peak dilatory responses of the penetrating arterioles preceded the local metabolic response of the parenchyma. CONCLUSION: Observation of hypoxia-exposed brain by the thinned-skull preparation combined with two-photon intra-vital microscopy revealed rapid vasodilatory responses in penetrating arterioles preceding parenchymal NADH elevation, suggesting the presence of acute hypoxia-sensing mechanisms involving specific segments of cortical arterioles within the neurovascular unit.

ROR gamma t is dispensable for the development of intestinal mucosal T cells.

To examine the origin of intestinal mucosal T cells and, in particular, unconventional CD8 alpha alpha(+) T cells, we have undertaken a thorough analysis of the gut immune compartment in euthymic and athymic mice carrying either wild-type or mutant transcription factor retinoic acid-related orphan receptor-gamma t (ROR gamma t). We identified a previously unrealized complexity of gut cryptopatch (CP) cells that challenges the previous assertion that CP cells comprise ROR gamma t-expressing adult counterparts of fetal lymphoid tissue inducer (Lti) cells. We showed that many CP cells express intermediate T cell differentiation markers, whether or not they express ROR gamma t, and found that CPs are not completely dependent on ROR gamma t, as previously reported, but merely fewer in number in the ROR gamma t-deficient condition. Indeed, c-kit(+)IL-7R(+)Lin(-)ROR gamma t(-) cells inside the CP and c-kit(+)IL-7R(+)Lin(-)ROR gamma t(-) and c-kit(+)IL-7R(+)Lin(-)ROR gamma t(low) cells outside the CP basically remain in the gut mucosa of ROR gamma t-deficient ROR gamma t(EGFP/EGFP) mice. Consistent with these non-Lti-like c-kit(+)IL-7R(+)Lin(-) cells being gut T cell progenitors, ROR gamma t-deficient mice develop the normal number of intestinal mucosal T cells. These results clearly reassert the intraintestinal differentiation of the body's largest peripheral T cell subpopulation.

Inverse correlation between activated protein C generation and carotid atherosclerosis in Type 2 diabetic patients.

AIMS: Activated protein C (APC) is a key regulator of the clotting system and immune responses. We studied the relationship between the degree of atherosclerosis as measured by the intima-media thickness (IMT) of carotid artery and APC generation in Type 2 diabetic patients. METHODS: Eighty-seven Type 2 diabetic patients and 35 control subjects participated. APC generation was assessed by the plasma APC-protein C inhibitor complex (APC-PCI) levels and the mean IMT of carotid artery was measured by ultrasonography. The plasma levels of the thrombin-anti-thromobin complex (TAT) and platelet-derived growth factor (PDGF) were measured by enzyme-linked immunoassays. RESULTS: Plasma TAT levels were significantly higher in diabetic patients [2.03 (1.12, 2.56) ng/ml, median (25th, 75th percentile)] compared with control subjects [0.85 (0.55, 2.08) ng/ml, P < 0.01]. Plasma APC-PCI levels were significantly lower in diabetic patients [0.93 (0.74, 1.22) ng/ml], than in control subjects [1.66 (1.25, 2.36) ng/ml, P < 0.001]. The mean IMT was significantly increased in diabetic patients (0.881 +/- 0.242 mm; mean +/- sd) compared with control subjects (0.669 +/- 0.140 mm; P < 0.01). Univariate analysis showed a significant and inverse correlation between plasma APC-PCI levels and mean IMT (r = -0.32, P < 0.005), and multivariate regression analysis confirmed the independent correlation (P < 0.05). Moreover, plasma APC-PCI levels significantly and inversely correlated with plasma PDGF levels in diabetic patients (r = -0.30, P < 0.01). CONCLUSIONS: These results suggest that decreased APC generation is associated with vascular atherosclerotic changes in Type 2 diabetic patients.

The free-radical scavenger, edaravone, augments NO release from vascular cells and platelets after laser-induced, acute endothelial injury in vivo.

In vitro and in vivo experimental models have demonstrated that vascular endothelial function is significantly impaired as a result of oxidative stress, mediated by the generation of oxygen-derived free radicals in response to chronic or acute inflammation. In particular, super-oxide () at specific concentrations leads to the impairment of nitric oxide (NO) bioactivity, and it is known that NO plays a fundamental role in the maintenance of vascular homeostasis. The relationship between reactive oxygen species (ROS) and NO release in thrombosis-related endothelial damage in the peripheral microvasculature remains unclear, however. The purpose of the present study was to investigate the effect of the free-radical scavenger, edaravone, on NO synthesis and thrombotic potential in arterioles after exposure to laser irradiation. Highly sensitive electrochemical NO microsensors were positioned in femoral arterioles of mice, and the kinetics of NO release were recorded in response to standardized laser irradiation in vivo. In addition, images of NO release from damaged vascular cells were investigated in a similar rat model using the NO-sensitive dye 4,5-diaminofluorescein diacetate (DAF-2DA). Thrombogenesis was assessed in carotid arterioles by continuous video microscopy using image analysis software. Laser irradiation led to NO release from perturbed endothelial cells and from platelet-rich thrombi. Edaravone had no significant effect on NO release in non-laser treated, intact endothelium compared with placebo. In contrast, edaravone demonstrated a dose-dependent effect on NO release and thrombogenicity. At a concentration of 10.5 mg/kg per h, edaravone promoted a 5-fold increase in NO and a reduction in platelet-rich thrombus volume to 58% of the placebo values. Our data provide direct evidence to confirm that acute endothelial damage in peripheral microvessels initially induces NO release and that the free-radical scavenger, edaravone, augments NO synthesis leading to suppression of platelet thrombus formation.

Elucidation of apoptosis induced by serum deprivation in cultured conjunctival epithelial cells.

BACKGROUND/AIMS: The conjunctival epithelial cell line, CCL20.2 (CCL), requires the presence of 10% fetal calf serum (FCS) in the medium to survive. To elucidate the molecular mechanism underlying such cell death, including the death signal for these cells, the activities of several caspases in the CCL were measured, and the effects of caspase inhibitors and serum components on cell death were examined. METHODS: CCL was grown in Medium 199 containing 10% FCS, and the medium was changed to Medium 199 with or without 10% FCS, or medium without 10% FCS but containing caspase inhibitors or serum components. After 24 hours' incubation, the enzyme activities of caspases 1, 3, 8, and 9 in the culture supernatants were measured, and the effects of caspase inhibitors and serum components-for example, growth factors, lactoferrin, retinoic acid, were investigated. RESULTS: DNA fragmentation was induced by serum deprivation, confirming that serum deprivation induces apoptosis in CCL. While the activities of caspases 3 and 8 were found to be increased, those of caspases 1 and 9 were not detected in the apoptotic cells. Z-VAD completely suppressed the caspase 3 activation, and specific inhibitors of caspases 1, 8, and 9 partially suppressed the activation. Serum deprivation induced a decrease in the cellular viability, which, however, partially recovered in the presence of caspase inhibitors, epidermal growth factor and retinoic acid. CONCLUSION: These results suggest that the apoptosis induced by serum deprivation involves caspases 1, 3, 8, and 9, and is suppressed by caspase inhibitors. EGF and retinoic acid have a key role in the maintenance of the ocular surface.

Possible participation of outer mitochondrial membrane cytonchrome B5 in steroidogenesis in zona glomerulosa of rat adrenal cortex.

Outer mitochondrial membrane cytochrome b5 (OMb) originally found in rat liver is an isoform of cytochrome b5 (b5) of the endoplasmic reticulum. In contrast to accumulated data on the physiological roles of b5, functions of OMb have not been well characterized except for its involvement in regeneration of ascorbic acid [i.e., in a semidehydroascorbate reductase (SDAR) system]. By using highly specific antibodies against rat OMb, we found immunohistochemically that OMb in the rat adrenal gland was most abundant in the zona glomerulosa (zG) among the three cortical zones, and the expression level was enhanced on angiotensin II-stimulation. SDAR activity was found in zG and inhibited by anti-OMb antibody. Moreover, the increase in plasma aldosterone concentration under Na+ -deficiency was suppressed by limited ascorbic acid (Asc) availability in rat mutants unable to synthesize Asc, while plasma corticosterone concentration was not affected. These data suggest that OMb, present abundantly in zG, participates in aldosterone formation in zG of rat under angiotensin II-stimulation through regeneration of Asc.

Primary embryonal carcinoma of heart with SVC syndrome.

We present a case report of a 25-year-old man with embryonal carcinoma of right atrium and multiple lung metastases featuring SVC syndrome. We resected the cardiac tumor which occupied the right atrium and performed left upper lobectomy. No tumor mass or vestige was detected in the testes. Cis-platinum based combination chemotherapy was performed for residual lung tumors, which leads to the complete remission.

No difference in the level of gastric mucosal cell apoptosis and proliferation in Helicobacter pylori-colonized p53 heterozygous knockout mice.

BACKGROUND: We previously reported that attenuated epithelial apoptosis and enhanced proliferation in comparison with mice might link to the specific carcinogenesis in Mongolian gerbils and suggested that the difference in both strains might be due to a difference in genetic background. p53 is a well-known tumour suppressor gene, mutation of which is also known to be involved in gastric cancer formation. AIM: The present study was designed to examine the level of gastric epithelial apoptosis and proliferation in p53 heterozygous knockout mice (p53+/-) colonized with Helicobacter pylori (Sydney strain: SS1). METHODS: Female p53+/- mice and wild-type controls were orally inoculated with SS1 and the stomachs were examined 24 weeks later. DNA fragmentation was measured by levels of cytoplasmic mono- & oligo-nucleosomes as well as by the TUNEL method. Gastric mucosal proliferative activity was morphometrically evaluated from the PCNA-stained tissue specimens. Gastric mucosal myeloperoxidase (MPO) activity was measured to evaluate mucosal inflammation. RESULTS: DNA fragmentation and the number of TUNEL-positive cells, as well as PCNA-positive cell number increased significantly in both groups of H. pylori-infected mice, suggesting that levels of apoptosis and proliferation may be independent of a deficiency of one p53 allele. MPO activity in p53+/- mice and wild-type controls increased to the same level. CONCLUSION: Although H. pylori inoculation per se induces an increase in cell turnover in mice, heterozygous mutation of p53 did not significantly modify the balance in cell apoptosis and proliferation.

Kupffer cell-mediated recruitment of rat dendritic cells to the liver: roles of N-acetylgalactosamine-specific sugar receptors.

BACKGROUND & AIMS: Tissue recruitment of dendritic cells (DCs) is essential for antigen presentation. This study aimed to examine cellular and molecular mechanisms for DC recruitment to the liver. METHODS: Purified rat DCs were injected into circulation and their traffics were analyzed in normal and Kupffer cell-depleted rats by intravital confocal microscopy and immunohistology. Affinities of DCs to sinusoidal cells were examined by a cell-binding assay. DC precursor recruitment was induced by particulate injection. RESULTS: Both DC precursors and DCs at the antigen-transporting stage could be recruited to the liver, and their majority initially showed a selective binding to Kupffer cells. In the Kupffer cell-depleted rats, DCs could neither be recruited to the liver nor adhere to sinusoidal walls. Pretreatment with varied monosaccharides showed that sugar residues consisting of N-acetylgalactosamine were necessary for this binding. The binding was calcium-dependent, implying the C-type lectin involvement. Furthermore, DCs could endocytose N-acetylgalactosamine polymers in a receptor-specific manner. CONCLUSIONS: The DC-Kupffer cell binding through N-acetylgalactosamine-specific C-type lectin-like receptors is crucial for DC recruitment to the liver. Rat DCs at least partly possess receptors for endocytosis of galactosylated antigens. These DC receptors as well as Kupffer cell lectins are presumably responsible for this binding.

ERK and p38 MAPK, but not NF-kappaB, are critically involved in reactive oxygen species-mediated induction of IL-6 by angiotensin II in cardiac fibroblasts.

We recently reported that angiotensin II (Ang II) induced IL-6 mRNA expression in cardiac fibroblasts, which played an important role in Ang II-induced cardiac hypertrophy in paracrine fashion. The present study investigated the regulatory mechanism of Ang II-induced IL-6 gene expression, focusing especially on reactive oxygen species (ROS)-mediated signaling in cardiac fibroblasts. Ang II increased intracellular ROS in cardiac fibroblasts, and the increase was completely inhibited by the AT-1 blocker candesartan and the NADH/NADPH oxidase inhibitor diphenyleneiodonium (DPI). We first confirmed that antioxidant N-acetylcysteine, superoxide scavenger Tiron, and DPI suppressed Ang II-induced IL-6 expression. Because we observed that exogenous H(2)O(2) also increased IL-6 mRNA, the signaling pathways downstream of Ang II and exogenous H(2)O(2) were compared. Ang II, as well as exogenous H(2)O(2), activated ERK, p38 MAPK, and JNK, which were significantly inhibited by N-acetylcysteine and DPI. In contrast with exogenous H(2)O(2), however, Ang II did not influence phosphorylation and degradation of IkappaB-alpha/beta or nuclear translocation of p65, nor did it increase NF-kappaB promoter activity. PD98059 and SB203580 inhibited Ang II-induced IL-6 expression. Truncation and mutational analysis of the IL-6 gene promoter showed that CRE was an important cis-element in Ang II-induced IL-6 gene expression. NF-kappaB-binding site was important for the basal expression of IL-6, but was not activated by Ang II. Ang II phosphorylated CREB through the ERK and p38 MAPK pathway in a ROS-sensitive manner. Collectively, these data indicated that Ang II stimulated ROS production via the AT1 receptor and NADH/NADPH oxidase, and that these ROS mediated activation of MAPKs, which culminated in IL-6 gene expression through a CRE-dependent, but not NF-kappaB-dependent, pathway in cardiac fibroblasts.

Organic phosphates as a new class of soluble guanylate cyclase inhibitors.

This study aimed to examine effects of varied organic phosphates on activities of soluble guanylate cyclase (sGC). The enzyme was purified from bovine lung. Physiologically relevant concentrations of ATP, 2,3-bisphosphoglyceric acid and inositol hexakisphosphate inhibited its enzyme activities under steady-state conditions as well as those determined under stimulation with S-nitroso-N-acetylpenicillamine, a nitric oxide donor, carbon monoxide or YC-1. Lineweaver-Burk plot analyses revealed that these three organic phosphates act as competitive inhibitors. Other organic phosphates such as cardiolipin and sphingomyelin but not inorganic phosphates exhibited such inhibitory actions. These results suggest that organic phosphates serve as inhibitors for sGC-dependent signaling events.

Increased expression of heme oxygenase-1 and bilirubin accumulation in foam cells of rabbit atherosclerotic lesions.

Heme oxygenase-1 (HO-1) catalyzes the regiospecific oxidative degradation of heme to biliverdin IXalpha, iron, and carbon monoxide. Biliverdin IXalpha is subsequently reduced to bilirubin IXalpha by biliverdin reductase. HO-1 expression is induced under various disease conditions, including atherosclerosis, but it is unknown whether HO-1 catalyzes heme breakdown in the regions at risk. Using hypercholesterolemic rabbits fed a cholesterol-enriched diet, we attempted to demonstrate the involvement of HO-1 induction and bilirubin IXalpha production in atherosclerotic regions. Expression levels of HO-1 mRNA were elevated in the aortas of hypercholesterolemic rabbits. In situ hybridization and immunohistochemistry revealed that mRNA and protein of HO-1 are induced in endothelial cells and foam cells (lipid-filled macrophages) in atherosclerotic lesions. Furthermore, immunohistochemistry with the use of an anti-bilirubin-IXalpha monoclonal antibody, 24G7, demonstrated accumulation of bilirubin IXalpha in foam cells, indicating that heme is actually degraded in atherosclerotic lesions. Remarkably, bilirubin IXalpha, like HO-1 protein, is predominantly accumulated in the perinuclear regions of foam cells. These results provide the first in vivo evidence of the colocalization of HO-1 and bilirubin IXalpha in foam cells, suggesting a role of HO-1 induction in the modulation of macrophage activation in atherosclerosis.

Relaxation effects of clustered particles.

Relations between spatial distribution of superparamagnetic iron oxide (SPIO) particles and the image contrast caused by SPIO were investigated. Actual clustering pattern of particles was measured in the liver and spleen of animals using intravital laser confocal microscopy. SPIO-doped phantoms with and without Sephadex beads were made to simulate these patterns, and relaxation parameters were measured using a 1.5-T clinical scanner. Finally, these results were compared to clinical image data using SPIO particulate agent. Intravital microscopy indicated that the clustering of latex beads was more predominant in hepatic Kupffer cells than in splenic macrophages (P < 0.001). Phantoms without Sephadex beads showed an approximately linear increase of 1/T1 (R1), 1/T2 (R2) and 1/T2* (R2*) values with increasing SPIO concentration. However, with Sephadex beads, R1 and R2 showed little change with increasing SPIO concentration, while R2* showed the same linear increase with SPIO. Also, the R2* values were higher with Sephadex beads. These results were consistent with the clinical imaging data, where signal reduction was significantly smaller in the spleen (-0.4% +/- 27.4%) than in the liver (50.4% +/- 16.8%, P < 0.00001) on T2*-weighted images, but the reduction in the spleen (47.2% +/- 16.1%) was equivalent to the liver (38.8% +/- 26.0%) on T2-weighted images.

Role of heme oxygenase-1 and Kupffer cells in the production of bilirubin in the rat liver.

Heme oxygenase (HO)-1, the heme-degrading enzyme in macrophages, plays a key role in bilirubin metabolism. HO-1 is expressed in various tissue macrophages, especially Kupffer cells. This study aimed to examine the roles of macrophages and HO-1 in the modulation of heme catabolism in rat livers. Rats treated with or without liposome-encapsulated dichloromethylene diphosphonate, a macrophage-depleting reagent, were administered with heat-denatured red blood cells (h-RBC), and the time course of the biliary output of bilirubin and the expressions of HO-1 mRNA and protein were monitored. Immunohistochemistry in the control rat liver revealed that Kupffer cells constitute a major cellular component expressing HO-1, while hepatocytes exhibited little expression. The levels of HO-1 expression in Kupffer cells were elevated immediately after injection of h-RBC. In Kupffer cell-depleted livers, however, HO-1-expressing cells were not detected even after h-RBC administration. HO-1 mRNA levels were elevated at 2 h after administration of h-RBC in control rat livers, while they were very low in Kupffer cell-depleted rat livers. The control and Kupffer cell-depleted groups exhibited distinct time courses of biliary bilirubin excretion. In the untreated control rats, total bilirubin excretion increased about two-fold at 5 h after h-RBC administration. In contrast, the Kupffer cell-depleting treatment decreased the level of bilirubin production; administration of h-RBC to Kupffer cell-depleted rats did not accelerate the generation of bilirubin. These results suggest that Kupffer cells serve both as a sensor for scenesent RBC clearance and an effector that upregulates heme-degrading capacity and bilirubin production.

Vascular smooth muscle cell-directed overexpression of heme oxygenase-1 elevates blood pressure through attenuation of nitric oxide-induced vasodilation in mice.

To elucidate pathophysiological roles of heme oxygenase (HO)-1 in regulation of vascular tone in vivo, we have developed and characterized transgenic (Tg) mice that overexpress HO-1 site specifically in vascular smooth muscle cells (VSMCs). The Tg mice were generated by use of human HO-1 cDNA under the control of SM22-alpha promoter. The HO-1 gene overexpression was demonstrated by Northern blot analysis and coincided with increases in the protein expression in VSMCs and total HO activities. Tg mice exhibited a significant increase in arterial pressure at various ages and displayed impaired nitrovasodilatory responses in isolated aortic segments versus nontransgenic littermates while enhancing their nitric oxide (NO) production. The pressure of Tg mice was unchanged by systemic administration of either N(omega)-nitro-L-arginine or SNP. Furthermore, the isolated aorta in these mice exhibited lesser extents of NO-elicited cGMP elevation via soluble guanylate cyclase (sGC), while exhibiting no notable downregulation of sGC expression. Such impairment of the NO-elicited cGMP increase was restored significantly by tin protoporphyrin IX, an HO inhibitor. On the other hand, 3-(5'-hydroxymethyl-2' furyl)-1-benzyl-indazol (YC-1), an NO-independent activator of sGC, increased cGMP and relaxed aortas from Tg mice to levels comparable with those from nontransgenic mice, which indicates that contents of functionally intact sGC are unlikely to differ between the two systems. These findings suggest that site-specific overexpression of HO-1 in VSMCs suppresses vasodilatory response to NO and thereby leads to an elevation of arterial pressure.

Professor Toshio Ito: a clairvoyant in pericyte biology.

Ito cells are liver-specific pericytes which were first described as Fett Speicherung Zellen, the fat-storing cells encircling outside sinusoidal endothelial cells, in 1951 by the late professor Toshio Ito. His pioneering approaches for morphological characterization of the cells stimulate investigators to further examine their functional roles in liver homeostasis: a body of evidence has been accumulated in recent years showing that the cells play a crucial role in storage and delivery of vitamin A, regulation of sinusoidal tone and local blood supply, and tissue repair and fibrosis. It is now widely accepted that microvascular pericytes including Ito cells serve as a key player that controls angiogenesis. Furthermore, recent studies support a concept that Ito cells constitutes a bridging apparatus mediating bidirectional metabolic interactions between sinusoids and hepatocytes, utilizing prostanoids and/or gaseous mediators such as nitric oxide and carbon monoxide as signaling molecules. This article reviews researches on this liver-specific pericyte and its leading roles in recent development of pericyte biology.

Roles of carbon monoxide in leukocyte and platelet dynamics in rat mesenteric during sevoflurane anesthesia.

BACKGROUND: Heme oxygenase 1 (HO-1), induced by a variety of stressors, provides endogenous carbon monoxide (CO) and bilirubin, both of which play consequential roles in organs. The current study aimed to examine whether induction of HO-1 and its by-products modulated endothelial interaction with circulating leukocytes and platelets evoked by sevoflurane anesthesia in vivo. METHODS: Rats, pretreated with or without hemin, were anesthetized with sevoflurane in 100% O2, and lungs were mechanically ventilated. Platelets labeled with carboxyfluorescein diacetate succinimidyl ester and leukocyte behavior in mesenteric venules were visualized during sevoflurane anesthesia at 1,000 frames/s using intravital ultrahigh-speed intensified fluorescence videomicroscopy. To examine the mechanisms for the effects of HO-1 on leukocyte and platelet behavior, these studies were repeated with superfusion of either CO, bilirubin, or Nomega-nitro-L-arginine methyl ester (L-NAME). RESULTS: As reported previously, the elevation of sevoflurane concentration evoked adhesive responses of leukocytes, concurrent with platelet margination and rolling. Pretreatment with hemin, a HO-1 inducer, prevented such sevoflurane-elicited changes in the microvessels. These changes were restored by zinc protoporphyrin IX, a HO inhibitor, and repressed by CO but not by bilirubin. During sevoflurane anesthesia, however, nitric oxide suppression by L-NAME deteriorated microvascular flows irrespective of the presence or absence of the HO-1 induction. CONCLUSIONS: These results indicate that endogenous CO via HO-1 induction attenuates sevoflurane-induced microvascular endothelial interactions with leukocytes and platelets, although local nitric oxide levels appear to dominate microvascular flow in situ.

Polaprezinc attenuates the Helicobacter pylori-induced gastric mucosal leucocyte activation in Mongolian gerbils--a study using intravital videomicroscopy.

BACKGROUND: We previously demonstrated that Helicobacter pylori colonization evokes gastric mucosal inflammation and an extensive increase in lipid peroxides and glutathione in Mongolian gerbils. Zinc and its derivative, polaprezinc, have been reported to be potent antioxidants in gastric mucosa. AIM: To examine the effect of polaprezinc on gastric mucosal oxidative inflammation in H. pylori-colonized Mongolian gerbils. METHODS: Sixty-eight male Mongolian gerbils were orally inoculated with H. pylori (ATCC43504, 5 x 10(8) CFUs/gerbil; H. pylori group) and 35 gerbils were inoculated with the culture media (control group). Twenty-two gerbils in the H. pylori and 13 gerbils in the control group were fed with diets containing polaprezinc (0.06%, 100 mg/kg, 10 times the usual clinical dose) (H. pylori + polaprezinc group, polaprezinc group). The remaining gerbils were fed a standard laboratory chow diet. Neutrophil infiltration, assessed histologically and by the activity of myeloperoxidase, the contents of CXC-chemokine (GRO/CINC-1-like protein) and the contents of thiobarbituric acid-reactive substances, was evaluated in each group 12 weeks after the inoculation. Separately, gastric mucosal leucocyte activation and capillary perfusion were also assessed using intravital microscopy 2, 4, 8 and 12 weeks after the inoculation. RESULTS: In all H. pylori-inoculated animals, the bacterial infection persisted throughout the experimental period. Gastric mucosal lesion formation in the H. pylori group was significantly inhibited in the H. pylori + polaprezinc group. Elevated levels of myeloperoxidase activity, GRO/CINC-1 and thiobarbituric acid-reactive substances in the H. pylori group at 12 weeks were attenuated significantly by polaprezinc treatment. Enhanced levels of venular leucocyte activation observed in the H. pylori group were attenuated significantly in the H. pylori + polaprezinc group during both the early phase (2 weeks) and late phase (12 weeks). CONCLUSION: Polaprezinc inhibited H. pylori-associated gastric mucosal oxidative inflammation, including initial micro-vascular leucocyte activation, in Mongolian gerbils.