Hiroshi Moriyama

Development, differentiation, and phenotypic heterogeneity of murine tissue macrophages.

In murine ontogeny, macrophage precursor cells develop in the yolk sac and fetal liver. Primitive macrophages also appear in the yolk sac, migrate to various tissues, and differentiate into several fetal macrophage populations. Because the development of the monocytic cell lineage is incomplete in the early stage of fetal hematopoiesis, primitive/fetal macrophages are considered to originate from granulocyte‐macrophage colony‐forming cells or earlier macrophage precursors, bypassing the early monocytic cell series. In adult mice rendered severely monocytopenic by administration of strontium‐89, resident macrophages are maintained by self‐renewal. In contrast, administration of liposome‐encapsulated dichloromethylene diphosphonate (clodronate) results in the elimination of various tissue macrophage populations. The repopulation of affected macrophages is dependent on the increase of precursors in the liver and spleen during the period of macrophage depletion. Such precursors reconstitute heterogeneous macrophage subpopulations. In mice homozygous for the osteopetrosis (op) mutation, the absence of macrophage colony‐stimulating factor (M‐CSF) activity results in a deficiency of monocytes and monocyte‐derived macrophages. However, immature macrophages are present in various tissues. Administration of M‐CSF to op/op mice induces the increased proliferative capacity and the morphological maturation of macrophages. However, the responses of individual tissue macrophage subpopulations to M‐CSF are different. These results indicate that macrophage development, differentiation, and proliferation are regulated by the tissue microenvironment including the in situ production of macrophage growth factors in both fetal and adult life.

Liposome‐encapsulated dichloromethylene diphosphonate induces macrophage apoptosis in vivo and in vitro

Dichloromethylene diphosphonate (MDPCl2) encapsulated in multilamellar liposomes was selectively incorporated by macrophages, immediately transferred to lysosomes, then released from liposomes into lysosomes by enzymatic digestion of the liposomal lipid layers. From 4 h after ingesting liposome‐encapsulated MDPCl2 murine macrophages in vivo and in vitro acquired the ultrastructural features of apoptosis, such as condensed nuclear chromatin, nuclear fragmentation, cell shrinkage, and blebbing of the plasma membrane. Murine peritoneal macrophages and isolated rat Kupffer cells incubated in the medium containing liposome‐encapsulated MDPCl2 increased DNA fragmentation in a dose‐dependent manner. Electrophoretic analysis of extracted DNA from the isolated Kupffer cells showed DNA fragmentation. Another diphosphonate, Alendronate (4‐amino‐1‐hydroxybutylidene‐1,1‐diphosphonate) had less potent macrophage cytotoxicity. However, MDPCl2, Alendronate, and gadolinium chloride in solution were not cytotoxic to macrophages. These results implied that the intralysosomal accumulation of MDPCl2 generates signals to induce macrophage apoptosis. J. Leukoc. Biol. 60: 337–344; 1996.

Pulmonary involvement in mixed connective tissue disease: comparison with other collagen vascular diseases using high resolution CT.

Purpose The purpose of this work was to compare the CT findings of lung involvement in patients with mixed connective tissue disease (MCTD) with those in patients with other CTDs: systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and polymyositis and dermatomyositis (PM-DM). Method CT scans of 35 patients with interstitial lung disease and associated MCTD were evaluated retrospectively. The CT assessment included determination of the findings and evaluation of whether the findings in MCTD were different from those in other CTDs. Results The frequency of ground-glass opacity in MCTD was significantly lower than in CTDs (p < 0.05). The frequency of honeycombing in MCTD was lower than in SSc (p < 0.05) and higher than in PM-DM (p < 0.005). Regarding the predominant CT patterns, the frequency of septal thickening in MCTD was significantly higher than in CTDs (p < 0.05). Conclusion CT findings in MCTD were a combination of those in other CTDs.

Macrophage differentiation and expression of macrophage colony-stimulating factor in murine milky spots and omentum after macrophage elimination.

To elucidate the differentiation mechanisms of macrophages in the murine omentum, we studied the repopulation of these cells and the expression of macrophage colony‐stimulating factor (M‐CSF) in the milky spots and omental tissues in mice depleted of macrophages following administration of liposome‐encapsulated dichloromethylene diphosphonate (clodronate). The macrophages in the omentum were spindle or dendritic in shape, expressed several macrophage‐specific antigens and Ia antigen, and phagocytized intraperitoneally injected carbon particles. In the milky spots, macrophages and macrophage precursors were detected, and the number of precursors increased alter elimination of macrophages by intraperitoneal injection of liposome‐encapsulated clodronate. Macrophage precursors in the milky spots proliferated, moved to the omentum, and transformed into dendritic‐shaped macrophages. Expression of M‐CSF mRNA extracted from the milky spots was markedly enhanced at 2 and 3 days after macrophage depletion. Localization of M‐CSF protein and mRNA was observed in the stromal cells of the milky spots. In osteopetrosis (op/op) mutant mice that are defective in the production of functional M‐CSF omental macrophages were absent. These results indicate that M‐CSF locally produced in the milky spots plays an important role in providing a microenvironment for development and differentiation of omental macrophages. J. Leukoc. Biol. 61: 436–444; 1997.

Preventive effect of irbesartan on bleomycin-induced lung injury in mice

BACKGROUND Idiopathic pulmonary fibrosis is a specific form of chronic fibrosing interstitial pneumonia that is limited to the lung. Angiotensin receptor blockers (ARBs) and peroxisome proliferator-activated receptor (PPAR) γ ligands have anti-inflammatory and anti-fibrotic effects. We investigated the effects of irbesartan-an ARB with PPAR γ activity-on the development of bleomycin-induced pulmonary fibrosis in mice. METHODS Lung injury was induced in imprinting control region (ICR) mice by intratracheal instillation of 2mg/kg of bleomycin. The treatment group orally received 20mg/kg of irbesartan for 5 consecutive days before instillation. The mice were sacrificed and were evaluated 14 days after bleomycin instillation. RESULTS Irbesartan reduced the fluid content and hydroxyproline level in the lung and improved the pathological findings as indicated by the Ashcroft score. Total cell counts, the numbers of macrophages, neutrophils, and lymphocytes, and the levels of transforming growth factor (TGF) β1 and monocyte chemotactic protein (MCP) 1 in the bronchoalveolar lavage fluid (BALF) were decreased. Treatment with a PPARγ antagonist GW9662 reversed some of the effects of irbesartan. CONCLUSIONS The results of this study indicated that irbesartan attenuated the development of bleomycin-induced pulmonary fibrosis in mice by decreasing TGF-β1 and MCP-1 via blocking of ATI, by binding to CCR2b, and by PPARγ-mediated inhibition of inflammation.

Preventive Effect of Hochu-ekki-to on Lipopolysaccharide-Induced Acute Lung Injury in BALB/c Mice

This study was designed to investigate the effect of Hochu-ekki-to (TJ-41), a Japanese herbal medicine, on the development of lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. ALI was induced in female BALB/c mice by the intranasal administration of 0.1 mg/kg LPS. The mice were divided into a group receiving normal feed and another group receiving feed mixed with TJ-41 at a dose of 1 g/kg/day for 8 weeks before LPS challenge. In the bronchoalveolar lavage fluid, the preadministration of TJ-41 caused significant reduction in the absolute number of total cells, neutrophils, and macrophages. The preadministration of TJ-41 significantly inhibited increases in the serum level of keratinocyte chemoattractant (KC), which is a murine chemotaxin for neutrophils that corresponds to human interleukin-8, with respect to its concentration at 24 h after LPS challenge. Furthermore, the histopathologic findings indicated that alveolitis with leukocyte infiltration in the alveolar space was less severe in the TJ-41-treated mice than in the control mice. These findings indicated that the preadministration of TJ-41 could show an inhibitory effect on ALI in this experimental murine system associated with the suppression of chemokine production.

Bronchoalveolar lavage fluid cells in mixed connective tissue disease

Objective:  Patients with mixed connective tissue disease (MCTD) exhibit clinical features of systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and polymyositis and dermatomyositis (PM–DM). The objective of this study was to clarify differences in BAL findings and immunophenotypes of BAL fluid (BALF) cells of patients with interstitial lung disease associated with these diseases.

Preventive effect of hochu‐ekki‐to, a Japanese herbal medicine, on bleomycin‐induced lung injury in mice

Objective:  Pulmonary fibrosis is thought to be closely associated with the T‐helper type‐2 (Th2) immune response. Recent studies have shown that hochu‐ekki‐to (TJ‐41), a Japanese herbal medicine, may correct the Th1/Th2 imbalance skewed to Th2. The present study was designed to investigate the preventive effect of TJ‐41 on the development of bleomycin (BLM)‐induced lung injury in mice.

Fatal acute interstitial pneumonia in a worker making chips from wooden debris generated by the Great East Japan earthquake and tsunami

A man was admitted to our hospital with shortness of breath. He was involved in making wood chips from contaminated debris created by the tsunami that occurred after the Great East Japan Earthquake. Fungi detected at his home and workplace were possible inducers of hypersensitivity pneumonitis, but the absence of precipitating antibodies countered this diagnosis. His rapid and progressive clinical course and surgical lung biopsy and bronchoalveolar lavage findings suggested acute interstitial pneumonia. Electron probe X-ray microanalysis revealed the deposition of excessive exogenous substances in bronchiolar regions. Inhalation of harmful materials was suspected to be the cause of acute lung injury.

Development of pulmonary alveolar proteinosis following exposure to dust after the Great East Japan Earthquake

We report a unique case of pulmonary alveolar proteinosis that developed 3 weeks after the Great East Japan Earthquake and the subsequent tsunami. The patient had inhaled dust repeatedly while visiting her devastated neighborhood without wearing a protective mask. Five weeks after the earthquake, lung samples taken from the patient showed foreign particle deposition; however, her serum was negative for GM-CSF autoantibody. The patients clinical symptoms resolved following whole lung lavage. We conclude that inhalation of fine dust particles after natural disasters may cause the onset of pulmonary alveolar proteinosis.