The involvement of matrix metalloproteinases in basement membrane injury in a murine model of acute allergic airway inflammation.

BACKGROUND: Airway remodelling in asthma such as subepithelial fibrosis is thought to be the repair process that follows the continuing injury as of chronic airway inflammation. However, how acute allergic inflammation causes tissue injury in the epithelial basement membrane in asthmatic airways remains unclear. Matrix metalloproteinases (MMPs) capable of degrading almost all of the extracellular matrix components have been demonstrated to be involved in cell migration through the basement membrane in vivo and in vitro. OBJECTIVE: We investigated the alterations of matrix construction and the role of MMPs in matrix degradation in the subepithelium during acute allergic airway inflammation. METHODS: Airway inflammation, the ultrastructure of the subepithelium and injury of types III and IV collagen in tracheal tissues from ovalbumin (OVA)-sensitized mice after OVA inhalation with or without the administration of tissue inhibitor of metalloproteinase-2 (TIMP-2) and dexamethasone were evaluated by cell counting in bronchoalveolar lavage (BAL) fluids, electron microscopy and immunohistochemistry, respectively. RESULTS: The disruption of the lamina densa and matrix construction and the decrease of the immunoreactivity for type IV collagen in subepithelium were observed in association with the accumulation of inflammatory cells in airways 3 days after OVA inhalation. This disorganization of the matrix components in the subepithelium, as well the cellular accumulation, was abolished by the administration of TIMP-2 and dexamethasone. The immunoreactivity for type IV collagen in the subepithelium in OVA-inhaled mice returned to the level of that in saline-inhaled mice 10 days after inhalation in association with a decrease of the cell numbers in the BAL fluid. The immunoreactivity for type III collagen was changed neither 3 nor 10 days after OVA inhalation. CONCLUSION: These results suggest that epithelial basement membrane gets injured by, at least in part, MMPs as a consequence of cell transmigration through the membrane during acute allergic airway inflammation.

Interaction between sarcomere and mitochondrial length in normoxic and hypoxic rat ventricular papillary muscles.

We hypothesized that the mitochondrial length may be altered according to changes in the sarcomere length, and that this relationship may be affected by exposure to hypoxia. Rat ventricular papillary muscles were isolated and immersed in normoxic or hypoxic solutions for 10 min. Sarcomeres of various lengths were obtained by fixing the papillary muscles in a slack or stretched state, or after exposure to a contracture solution containing saponin and CaCl(2). The mitochondrial length measured using electron microscopy significantly correlated to the length of the adjacent sarcomere in both the normoxic (n=767) and hypoxic (n=1145) groups (P<.0001). The slope of the regression line, however, was significantly less steep, and its intercept was significantly larger in the hypoxic group than in the normoxic group (analysis of covariance). When we analyzed the mitochondrial lengths among the three sarcomere-length subgroups (<1.5, 1.5-2.0, and >2.0 microm), the mitochondrial length was significantly shorter in the hypoxic condition than in the normoxic condition at sarcomere lengths greater than 2.0 microm. Staining for desmin, the major muscle-type intermediate filament, the longitudinal system of which connects the mitochondria with the Z bands of sarcomeres, showed a clear cross-striation pattern in both papillary muscles with and without the exposure to hypoxia, suggesting that desmin was preserved after the exposure to hypoxia. These data indicate that the mitochondrial length changes according to changes in the sarcomere length, suggesting the possible role of mitochondria as an internal load against myocyte contraction. It is also suggested that mitochondria exposed to hypoxia may be more resistive to both compression and stretch in a longitudinal direction than those in the normoxic condition.

Overexpression of insulin-like growth factor-I in hearts of rats with isoproterenol-induced cardiac hypertrophy.

Increased levels of plasma catecholamine lead to cardiac hypertrophy via the alpha-, beta-adrenergic receptors, and partially, type 1 angiotensin II (AT1) receptor. However, it remains unclear whether other factors are involved in catecholamine-induced cardiac hypertrophy. We investigated the expression of insulin-like growth factor (IGF)-I in hearts of male Wistar rats infused with a beta-adrenergic agent, isoproterenol (ISO) (3 mg/kg/day), with or without an AT1-receptor antagonist, TCV-116 (10 mg/kg/day). Cardiac myocytes became hypertrophied 1 day after the beginning of ISO administration. ISO induced a biphasic increase of cardiac myocytes positive for IGF-I protein in the early and late phases of the study period, whereas IGF-I gene expression was upregulated only in the late phase by ISO. TCV- 116 abolished the upregulation of IGF-I gene and protein expression in the late phase in association with the regression of cardiac hypertrophy. These results suggest that ISO-induced cardiac hypertrophy is mediated, at least in part, by IGF-I, the expression of which is upregulated through the activation of AT1 receptor.

Differential expression of alpha 1, alpha 3 and alpha 5 integrin subunits in acute and chronic stages of myocardial infarction in rats.

OBJECTIVE: Anchoring cardiac myocytes to extracellular matrix, which is mediated mainly by integrins on their surfaces, is important for maintaining the architecture of myocardial tissues and transmitting mechanical force. We evaluated the expression of alpha integrin subunits on myocytes and the accumulation of interstitial collagen and fibronectin at acute and chronic stages after myocardial infarction. METHODS: Myocardial infarction was induced by ligation of left coronary arteries in rats. The expression of alpha 1, alpha 3 and alpha 5 integrin subunits, and accumulation of collagen and fibronectin were analyzed with immunohistochemistry or sirius-red staining. RESULTS: In hearts without infarction, moderate expression of the alpha 3 subunit and only slight expression of the alpha 5 subunit were observed on myocytes. In the first week after infarction, the alpha 1 subunit, collagen and fibronectin were increased only in the peri-infarcted area, while the alpha 5 subunit was increased both in peri-infarcted and non-infarcted areas. At day 42, the expression of the alpha 1 subunit and collagen were still increased, although the alpha 5 subunit and fibronectin were decreased. The expression of the alpha 3 subunit was not altered throughout the experimental period. CONCLUSION: These data suggest that integrin subunits play an important role in healing and remodeling processes after myocardial infarction.

Immunohistochemical analysis of platelet-derived growth factor-B expression in myocardial tissues in hypertrophic cardiomyopathy.

Intimal and/or medial hyperplasia of intramyocardial small vessels is thought to be one of the causes of myocardial ischemia in hypertrophic cardiomyopathy (HCM). However, the pathogenesis of such vascular lesions in HCM is not yet known. To evaluate the pathogenic role of platelet-derived growth factor (PDGF-B) and basic fibroblast growth factor (b-FGF), which have a potential to induce cellular and molecular changes observed in the vessels in HCM, we examined the expression of these molecules and PDGF receptors in cardiac tissues from six patients with HCM and seven controls using immunohistochemistry. The percentage of PDGF-B positive cells in the myocyte population in HCM was significantly higher than that in controls (52.6 +/- 16.2 (mean +/- SD) vs. 21.6 +/- 9.6, p < 0.01). PDGF-B was also observed in vascular regions in HCM (61.1 +/- 25.5% of arterioles) but not in controls. There were no significant differences in the expression of b-FGF and PDGF receptors in the myocyte and non-myocyte populations and the vascular regions between the HCM and control groups. Our study revealed that the expression of PDGF-B protein was up-regulated in HCM, suggesting the contribution of this molecule to the development of intramyocardial vasculopathy.

Patient background of the Pokemon phenomenon: questionnaire studies in multiple pediatric clinics.

Many children in Japan developed various neuropsychological problems, including seizures, while watching the program Pocket Monster, televised on 16 December 1997. To examine the basis for this incident, we have performed a survey of volunteering children and their parents who visited our pediatric clinics for other reasons from 8 January to 28 February 1998. Children and their parents filled out questionnaires. Among the total of 662 children surveyed, the great majority (603, 91.1%) was found to have watched the Pocket Monster program and 30 individuals (5.0% of viewers) complained of variable degrees of neuropsychological abnormalities. These included seizures (two cases), headache (nine cases), nausea (eight cases), blurred vision (four cases), vertigo (two cases), dysthymia (two cases) and vomiting (one case). Nearly half (14) of these children developed symptoms during or immediately after watching the program, while the remainder did so later. Representative cases are reported and other statistical aspects are discussed.

Haematological improvement by long-term administration of recombinant human granulocyte-colony stimulating factor and recombinant human erythropoietin in a patient with severe aplastic anaemia.

A 6-year-old girl with post-hepatitic severe aplastic anaemia was referred to our hospital. Haematological examination showed a haemoglobin level of 5.2 g/dl, platelet count of 8,000/microliters, and white blood cell count of 130/microliters with 17% neutrophils. She was treated with recombinant human granulocyte-colony stimulating factor (15 micrograms/kg/day i.v.) and cyclosporin A (6 mg/kg/day p.o.). The absolute neutrophil count gradually increased, but Hb and platelets were not improved. The intravenous administration of recombinant human erythropoietin (100 U/kg three times a week) was started, and the reticulocyte count reached 20,000/microliters on day 12. The platelets increased to 81,000/microliters after 16 months of combined administration of recombinant human granulocyte-colony stimulating factor, recombinant human erythropoietin and cyclosporin A. After 20 months of combined administration, the haematological results were: Hb, 13.1 g/dl; platelets 80,000/microliters; WBC, 9500/microliters with 40% neutrophils. After recombinant human granulocyte-colony stimulating factor treatment, the myeloid elements of the bone marrow and the number of granulocyte-macrophage colony forming units increased. Bone marrow erythropoiesis and erythroid colonies also increased after recombinant human erythropoietin administration. The clinical course suggested a beneficial effect of haemopoietic growth factors and cyclosporin A in post-hepatitic aplastic anaemia.

Relation of serum alkaline phosphatase to liver scintigram in patients with hepatocellular carcinoma.

Serum Alkaline Phosphatase (ALP) was studied in relation to liver scintigrams of 54 patients with hepatocellular carcinoma. The ALP activity was higher with larger tumors and in multiple tumors. Within the single tumor group, the activity was higher when the tumor was located in the hilum than in the periphery. The incidence of ALP-1 isoenzyme (bile ALP) roughly paralleled the total ALP activity. These results suggest that the variation of serum ALP seen in each individual patients with hepatocellular carcinoma reflects the volume of cholestatic liver tissue, which is changed by the number, size and localization of the tumor nodules in the liver.