Motohiro Kurosawa

Human mast cells produce matrix metalloproteinase 9.

Extracellular matrix‐destructive enzymes, like matrix metalloproteinases (MMP), have been recognized in the process of inflammation and tissue remodeling and repair. The affected tissues often contain markedly increased numbers of mast cells. Although mast cells are capable of activating latent collagenase and proMMP, it has so far been unknown whether human mast cells themselves produce and secrete MMP9. In this study, MMP9 production by cord blood‐derived cultured human mast cells and HMC‐1 human mast cells was examined by reverse‐transcriptase PCR, gelatin zymography and Western blot analysis using an antibody against MMP9. Cultured mast cells and HMC‐1 cells treated with phorbol 12‐myristate 13‐acetate were shown to express MMP9 mRNA, and the cultured conditioned media from these cells showed gelatinolytic activity, identical with MMP9. Immunohistochemical examination was performed to detect MMP9 in tissue mast cells; mast cells localized in the skin, lung and synovial tissue showed strongly positive reactions for MMP9. Thus, these findings indicate that human mast cells can produce MMP9, which might contribute to extracellular matrix degradation and absorption in the process of allergic and nonallergic responses.

Tubulointerstitial mast cell infiltration in glomerulonephritis

Mast cells are involved in chronic inflammation and tissue fibrosis. To determine whether these cells are also involved in tubulointerstitial injury in glomerulonephritis, we assayed mast cell infiltration in the kidneys of 107 patients with primary or secondary glomerulonephritis. Using a monoclonal antihuman tryptase antibody, we detected mast cells in the renal cortical tubulointerstitium, the periglomerular areas, and the medullary interstitium, but not in glomeruli. Renal cortical tubulointerstitial mast cells, including periglomerular area, were estimated as 0.8+/-1.6 cells/mm2 in minimal change nephrotic syndrome (n=7), 1.5+/-0.7 cells/mm2 in minor glomerular abnormalities without nephrotic syndrome (n=7), 6.5+/-7.7 cells/mm2 in membranous nephropathy(n=10), 12.9+/-15.5 cells/mm2 in lupus nephritis (n=15), 13.4+/-8.3 cells/mm2 in focal segmental glomerular sclerosis (n=6), 18.5+/-21.1 cells/mm2 in ANCA-related nephropathy (n=5), 19.8+/-14.2 cells/mm2 in membranoproliferative glomerulonephritis (n=5), 21.3+/-17.7 cells/mm2 in immunoglobulin A (IgA) nephropathy (n=42), and 33.0+/-33.8 cells/mm2 in diabetic nephropathy (n=10). Except for patients with the rapidly progressive glomerulonephritic syndrome (RPGN), the number of infiltrating mast cells significantly correlated with the serum concentration of creatinine at the time of renal biopsy (r=0.59; P < 0.0001) and with the intensity of tubulointerstitial injury as measured by leukocyte infiltration (r=0.72; P < 0.0001) and fibrosis (r=0.75; P < 0.0001). In contrast, mast cell infiltration did not correlate with urinary protein excretion. In relation to serum creatinine concentration, the number of mast cells was fewer in patients with RPGN than in those with chronic glomerulonephritis. These data suggest that mast cells may contribute to the renal deterioration in glomerulonephritis by inducing chronic tubulointerstitial injury.

Increased levels of blood platelet‐activating factor in bronchial asthmatic patients with active symptoms

Levels of platelet‐activating factor (PAF) in blood from 12 bronchial asthmatic patients (six atopic and six nonatopic) were measured by radioimmunoassay after lipid extraction and separation by high‐performance liquid chromatography. None of the patients were given disodium cromoglycate and prednisolone, and they were instructed to take only regular medications during the tests. Blood was drawn from the patients in a fasting state, and PAF levels were compared between the times when they were free of asthmatic symptoms and when they had mild spontaneous attacks. Ten (six atopic and four nonatopic) out of 12 patients, when they had the asthmatic attacks, showed higher levels of PAF than when they were free of the symptoms. Blood PAF levels of the patients with the active symptoms were significantly higher than those of normal healthy control subjects, suggesting that PAF may play a role in bronchial asthma.

Elevated levels of peripheral-blood, naturally occurring aliphatic polyamines in bronchial asthmatic patients with active symptoms

The levels of peripheral‐blood, naturally occurring aliphatic polyamines, such as putrescine, spermidine, and spermine, from 21 bronchial asthmatic patients (11 atopics and 10 nonatopics) were measured by postcolumn derivatization high‐performance liquid chromatography analysis. None of the patients, except the 44‐year‐old woman in the case report below, were given prednisolone, and they were instructed to take only regular medication during the tests. Blood was drawn from the patients in a fasting state, and the polyamine levels were compared between the times when they were free of asthmatic symptoms and when they had mild spontaneous attacks. Nine (5 atopics and 4 nonatopics), 6 (3 atopics and 3 nonatopics), and 4 (3 atopics and 1 nonatopic) out of 20 patients, when they had relatively mild asthmatic attacks, showed higher putrescine, spermidine, and spermine levels, respectively, than those of normal healthy control subjects. The levels of peripheral blood polyamines from a 44–year‐old atopic bronchial asthmatic woman, who was admitted to the hospital with severe asthmatic attacks, were measured serially, and the putrescine and spermidine levels were found to be elevated during the asthmatic attacks, returning to normal levels in parallel with the clinical course. These data may suggest a role for naturally occurring aliphatic polyamines in bronchial asthma.

Membranocystic changes in the panniculitis of dermatomyositis

Summary Clinically apparent paniculatus is rare in dermatomyositis. The common histopathological landings are infiltration of lymphocytes, epithelioid cells and plasma cells in the fat lobules, along with varying degrees of fat degeneration and fibrosis. We report a 65‐year‐old woman with dermatomyositis who developed paniculatus with a characteristic histological change known as a membranocystic lesion. Although this change has been observed in various diseases affecting the subcutaneous fat tissue, it has rarely been reported in dermatomyositis. Dermatomyositis should be included in the diseases showing a membranocystic lesion.

Expression of the Interleukin-8 Receptors CXCR1 and CXCR2 on Cord-Blood-Derived Cultured Human Mast Cells

Background: An increase in mast cell number at sites of inflamed tissues has been observed. However, the expression of CXC chemokine receptors on human mast cells is poorly understood. Methods: Cultured human mast cells were raised from human umbilical cord blood cells in the presence of stem cell factor and interleukin-6 (IL-6). The expression of surface chemokine receptors on the mast cells was analyzed by flow cytometry and that of mRNA was examined by the method of reverse transcriptase-polymerase chain reaction (RT-PCR). As functional assays for the receptors, mast cell migration was examined by a microchemotaxis assay and changes in the cytosolic free intracellular calcium concentrations ([Ca2+]i) was measured using fura-2-loaded mast cells, respectively. Results: Expression of IL-8 receptors CXCR1 and CXCR2 was demonstrated by flow cytometry and of both mRNA by RT-PCR; however, CC chemokine receptors including CCR3 were not expressed on cord-blood-derived cultured human mast cells. IL-8 and its homologues showed chemotactic activity toward them in a dose-dependent manner, and IL-8 induced a dose-dependent rapid and transient increase in [Ca2+]i in the mast cells. Conclusions: Our results suggest the surface expression of functional CXCR1 and CXCR2 on cord-blood-derived cultured human mast cells.

Role of thromboxane A2 synthetase inhibitors in the treatment of patients with bronchial asthma

Asthma results from complex interactions among inflammatory cells, mediators, and the cells and tissues resident in the airways and is characterized by airway obstruction, airway inflammation, and airway hyperresponsiveness. Treatment of asthma should address not only the airway obstruction but also the chronic inflammation that may lead to hyperresponsiveness. In Japan, where the death rate from asthma has not increased despite increasing numbers of patients, treatment of bronchial asthma relies on the use of oral prophylactic antiasthma drugs, such as thromboxane synthetase inhibitors. Thromboxanes may facilitate the effect of acetylcholine on the airways and may be involved in hyperresponsiveness. Experiments using animal models have shown that thromboxane synthetase inhibitors have prevented increased airway reactivity after exposure to allergens and irritants. Double-blind clinical trials have shown that treatment with the thromboxane A2 synthetase inhibitor ozagrel hydrochloride significantly reduced the need for concomitant steroid therapy, compared with treatment with azelastine hydrochloride. This review discusses the role of thromboxane A2 synthetase inhibitors in the treatment of patients with bronchial asthma.

Phosphorylation and dephosphorylation of protein in regulating cellular function

Phosphorylation state of cellular proteins reflects the balance between the activities of protein kinases and phosphoprotein phosphatases. The increase in cellular protein phosphorylation in response to stimuli can be achieved by either activating protein kinases and/or promoting the turnover of the protein phosphatases. This review will summarize current knowledge of the control of phosphorylation and dephosphorylation of protein in cells.

Inhibitory Effects of Vasoactive Intestinal Peptide on Superoxide Anion Formation by N-Formyl-Methionyl-Leucyl-Phenylalanine-Activated Inflammatory Cells in vitro

Effects of vasoactive intestinal peptide (VIP) on superoxide anion (O2-) formation by N-formyl-methionyl-leucyl-phenylalanine (fMLP)-activated inflammatory cells from healthy volunteers were investigated using 2-methyl-6-[p-methoxyphenyl]-3,7-dihydroimidazo [1,2-a]pyrazin-3-one (MCLA) as a chemiluminescence probe. VIP inhibited the maximal light intensity of MCLA-dependent luminescence in a dose-dependent manner by the activated peripheral blood neutrophils, mononuclear cells and also by the human monoblast cell line U937, the capacity of which for O2- formation was induced by pretreatment with interferon-gamma. 3 x 10(-6) M VIP also inhibited O2- formation by the activated peripheral blood eosinophils and alveolar macrophages obtained by bronchoalveolar lavage.

Quantitative Analysis of Mast Cells in Benign and Malignant Breast Lesions

Background: It has been reported that the number of mast cells was significantly greater in malignant breast carcinomas than in benign breast lesions. This was due to tryptase-containing mast cells while tryptase, chymase-containing mast cells had no effect. However, analysis of mast cells in breast carcinomas and benign breast lesions based on their histological findings remains to be elucidated. Methods: Using immunohistochemical methods morphological examinations of mast cells were undertaken in benign and malignant breast tissues from 51 patients (30 benign, 21 malignant), which were formalin-fixed and paraffin-embedded. In the study with malignant breast tissues, samples of malignant tissues and adjacent healthy tissues were obtained from a single patient, and the number of mast cells was compared. Results: Among benign breast tissues, the number of mast cells in intracanalicular fibroadenoma was significantly lower than that in pericanalicular fibroadenoma as well as that in mastopathy. The number of mast cells was significantly greater in malignant lesions than that in benign lesions. The number of mast cells in scirrhous carcinoma and that in solid-tubular carcinoma were significantly increased compared with that in adjacent healthy tissues. In addition, the number of mast cells in scirrhous carcinoma was highest among breast carcinomas, and significantly greater than that in papillotubular carcinoma. Conclusion: We were the first to find the significant lower number of mast cells in intracanalicular breast fibroadenoma when compared with that in pericanalicular fibroadenoma as well as that in mastopathy. Moreover, the number of mast cells in scirrhous carcinoma was significantly greater than that in papillotubular carcinoma.