Yoshinosuke Fukuchi

Endothelin-1 stimulates arachidonate 15-lipoxygenase activity and oxygen radical formation in the rat distal lung

We investigated the effects of intravenous bolus of endothelin-1 on the metabolism of eicosanoids and oxygen radicals in the distal lung unit of the rat. Intravenous bolus of endothelin-1 caused a significant increase in 15-hydroxyeicosatetraenoic acid of bronchoalveolar lavage fluid and oxygen radicals produced by the bronchoalveolar cells. Endothelin-1 exhibited a stimulatory effect on the 15-lipoxygenase activity in the lung homogenate. Thus, endothelin-1 may contribute to the inflammatory and hyperreactive process of lungs, by enhancing the release of 15-hydroxyeicosatetraenoic acid and oxygen radicals in the distal lung unit.

Increased Spontaneous Production and Generation of Superoxide Anion by Blood Neutrophils in Patients with Asthma

Spontaneous production and PMA- and opsonized zymosan- stimulated generation of superoxide anion by blood cells in asthmatic patients were compared with those in normal volunteers and chronic obstructive pulmonary disease (COPD) patients using a lucigenin-dependent chemiluminescence method. Superoxide anion generation by 100 microl of blood in patients with asthma and/or COPD was significantly greater than that in normal subjects [asthma: 5684 +/- 253 chemiluminescence (CL); COPD: 4994 +/- 240 CL; normal: 2543 +/- 213CL]. This is consistent with the increased superoxide generation per leukocyte (PMN) in these patients (Asthma: 1.56 +/- 0.08 CL/PMN; COPD: 1.31 +/- 0.08 CL/PMN; normal: 0.83 +/- 0.07 CL/PMN. However, spontaneous production of superoxide by individual PMNs was increased only in asthmatic patients, compared with that in normal subjects (Asthma: 0.14 +/- 0.02 CL/PMN; COPD: 0.07 +/- 0.01 CL/PMN; normal: 0.07 +/- 0.01 CL/PMN. These results indicate that the respiratory burst is enhanced in both asthmatic patients and COPD patients, and that superoxide production by resting neutrophils is also increased in asthmatic patients, but not in COPD patients, compared with normal subjects.

The effects of aging on the function of alveolar macrophages in mice.

In order to determine whether the function of alveolar macrophages (AM) is modulated by aging, we measured the TNF-alpha production, phagocytic function, and surface antigen expression of AM from young and old mice. When AM were primed by IFN-gamma (500 units/ml) and triggered by LPS (100 micrograms/ml), TNF-alpha production by AM was significantly smaller in old mice as compared with young mice (young mice: 161.7 +/- 28.2 units/ml; old mice: 89.3 +/- 13.6 units/ml, P < 0.05). The percentage of AM which phagocytosed latex particles (more than one particle) in old mice was significantly lower than in young mice (young: 78.1 +/- 2.5%; old: 62.8 +/- 3.4%, P < 0.05). Ia antigen expression of the AM was significantly higher and asialo-GM1 antigen expression was significantly lower in old mice than in young mice (Ia: young, 0.030 +/- 0.005; old, 0.092 +/- 0.024, P < 0.05; asialo-GM1: young, 0.-9 +/- 0.01; old, 0.75 +/- 0.07, P < 0.01). These results suggest that alveolar macrophage function is at least decreased in part with aging in mice.

Inhibition of Mouse Alveolar Macrophage Production of Tumor Necrosis Factor Alpha by Acute in vivo and in vitro Exposure to Tobacco Smoke

We investigated the effects of tobacco smoke exposure on the production of tumor necrosis factor alpha (TNF alpha) by alveolar macrophages (AM) in mice (C57BL/6). The results obtained are as follows: (1) In vivo tobacco smoke exposure caused a significant decrease in the production of TNF alpha by AM with the stimulation of lipopolysaccharide (LPS; control group: 19.32 +/- 5.52 U/ml, smoked group: 4.28 +/- 0.98 U/ml; p less than 0.05). (2) In vitro exposure of AM to tobacco smoke extracts (water-soluble extracts) also caused a decrease in the production of TNF alpha up to 93% of control with stimulation of LPS (p less than 0.05) without any decrease in cellular viability. We concluded that the production of TNF alpha by AM was impaired by smoking via direct action of the factors present in tobacco smoke.

Biochemical characteristics of lungs in senescence-accelerated mouse (SAM).

This study examined age-related biochemical changes of the lung in an animal model of senile lung, senescence-accelerated mouse (SAM). Bronchoalveolar lavage (BAL) was performed on two strains of SAM, the senescence-prone strain (SAM P2) and the senescence-resistant strain (SAM R1), as well as on normal ageing C57 black mice (C57BL), aged 1-24 months. Elastase-like and elastase inhibitory activity of BAL fluid (BALF), glutathione (GSH) and oxidized GSH (GSSG) content both of BALF and lung tissue, and oxygen radical generation of free lung cells obtained by BAL were examined in the three strains of mice. Cell populations did not change throughout the life in SAM strains and C57BL. The elastolytic activity in SAM was greater than in C57BL, but there was no change with age. Both a decreased content of GSH and an increased oxidation of the GSH in BALF were markedly observed with ageing in SAM P2. In the lung tissue, the GSSG/GSH ratio in SAM strains was consistently greater than that in C57BL, suggesting that the GSH redox cycle of the lung may be impaired in SAM strains. The oxygen radical generation by free lung cells increased with age in all three strains, but the increase was earlier and more pronounced in SAM P2 than in the other two strains. In conclusion, an impaired GSH redox cycle and an increased formation of oxygen radicals are observed in the lungs of SAM with increasing age.

Age-related changes in the antioxidant screen of the distal lung in mice

We studied the influence of age on glutathione (GSH) content in the distal lung and the lung tissue of mice. From 1 to 28 months of age, the quantity of GSH and glutathione disulfide (GSSG) in bronchoalveolar lavage (BAL) fluid and in the lung tissue were determined. The GSH content in BAL fluid, which reflects the antioxidant screen of the distal lung, decreased with advancing age. The ratio of GSSG to GSH increased in later life, suggesting increase of oxidation of the epithelial lining fluid in old mice. The GSH content in the lung tissue also decreased with aging. Therefore the lower respiratory tract may be less able to defend against external attack, including attack by oxygen-derived active molecules, in senescent mice. The decrease of the antioxidant screen of the distal lung may be associated with impaired lung defense in relation to oxidant-antioxidant balance in aged mice.

Influences of chronic tobacco smoke inhalation on aging and oxidant—antioxidant balance in the senescence-accelerated mouse (SAM)-P/2

We studied the influences of chronic tobacco exposure on aging and oxidant-antioxidant balance in two different strains of mice, hitherto called SAM (senescence-accelerated mice). One is a senescence-prone strain, SAM-P/2, and another is a senescence-resistant strain, SAM-R/1. We used 100 male mice--20 young (12 weeks of age) mice and 30 mature (24 weeks of age) mice from each strain. Half of each series were housed in a Hamburg II machine and exposed to tobacco smoke inhalation for five weeks. The result was that fewer of the mature SAM-P/2 survived compared with the mature SAM-R/1 after chronic tobacco inhalation. The grading of senility in the mature SAM-P/2 was also significantly higher than that in the mature SAM-R/1. The reduction of glutathione contents of blood and liver after tobacco exposure in the mature SAM-P/2 was greater than that in the young SAM-P/2 and the mature SAM-R/1. Moreover, oxygen radical generation of total blood cells stimulated by phorbol-myristate-acetate or opsonized zymosan showed a greater increase in the mature SAM-P/2 compared to the young SAM-P/2 and the mature SAM-R/1. These results indicate that the senescence-prone strain (SAM-P/2) was more susceptible to tobacco smoke exposure than the resistant strain (SAM-R/1). The impaired oxidant-antioxidant balance in the SAM-P/2 may therefore contribute to the process of senescence acceleration.

A new murine model of aging lung : the senescence accelerated mouse (SAM)-P

The senescence accelerated mouse (SAM) has recently been characterized as a unique model to investigate age-related disorders, including amyloidosis, cataract, osteoporosis and dementia. However, little is known as to the properties of the lung in these animals. Tobacco smoke is also associated with enhanced loss of elastic recoil and the development of emphysema. We have attempted to examine morphological as well as biochemical changes of the distal lung in SAM-P/2, as the senescence-prone series and SAM-R/1, as the senescence-resistant series. The animals were intermittently exposed to tobacco smoke or air by Hamburg II machines for 5 weeks. Then both groups of animals were killed for histologic and biochemical study. Compared with SAM-R/1, SAM-P/2, even with air exposure, showed a higher value of the mean linear intercept without alveolar wall destruction. It became even greater due to tobacco exposure with emphysematous change. Tobacco exposure accumulated inflammatory cells into alveoli in SAM-P/2, but not in SAM-R/1. Oxygen radical generation by those cells was also higher in SAM-P/2. Analysis of bronchoalveolar lavage fluid in SAM-P/2 after tobacco exposure disclosed increases in albumin content, total protein content and elastase-like activity. There were decreases in the ratio of elastase inhibitory capacity (EIC) to trypsin inhibitory capacity (TIC), contents of glutathione and total free thiol groups. Moreover, SAM-P/2 showed significantly lower EIC/TIC ratio in serum, even with air exposure, than that of SAM-R/1. These results indicate that SAM-P/2 can be a good model for the study of natural evolution of the aging lung as well as its susceptibility to tobacco smoke in the development of emphysema.

Influences of cisplatin combination chemotherapy on oxygen radical generation by blood in elderly and adult patients with lung cancer

Oxygen radical generation by blood cells before and after chemotherapy was investigated in 16 elderly (72.8 +/- 1.0 years) and 14 adult (45.0 +/- 2.4 years) patients with lung cancer, using a lucigenin-dependent chemiluminescence method. The oxygen radical generation by 100 microliters of blood before chemotherapy in the elderly and the adults was 3,784 +/- 123 and 3,969 +/- 125 chemiluminescence (CL), respectively. The value decreased gradually and reached a nadir at 2 weeks after therapy (elderly: 1,090 +/- 37; adult: 1,114 +/- 38 CL). Peripheral leukocyte counts also reached a nadir then: 1,308 +/- 140 and 1,288 +/- 44/mm3, respectively. However, the oxygen-radical-generating activity per leukocyte was not different before and after the therapy (elderly: 0.94 +/- 0.14 CL before to 0.83 +/- 0.09 CL after; adult: 0.97 +/- 0.13 CL before to 0.87 +/- 0.10 CL after). These results indicate that a decrease in oxygen radical generation by blood following chemotherapy is mainly due to a decrease in the number of polymorphonuclear neutrophils both in elderly and adult patients.

Age changes in visceral content of glutathione in the senescence accelerated mouse (SAM)

Free radical formation is known to play a role in the aging processes. However, it is still disputable whether the scavengers of free radicals including glutathione (GSH) decrease during aging. The senescence accelerated mice (SAM) are known to show age-related disorders. Some of these syndromes were thought to be closely associated with oxidative damages. Using the two strains of SAM, SAM-R/1 and SAM-P/2, we examined age-related changes in GSH content in the tissues and its oxidation. In the eye, GSH levels were significantly decreased at the age of 16 months in SAM-P/2 and female SAM-R/1. The ratio of oxidized glutathione to total GSH increased, indicating GSH may play an important role in the eyes. But there were no remarkable age-related changes in GSH contents of other tissues such as liver, kidney and lung in both SAM-R/1 and SAM-P/2. These data suggest that the GSH level of the tissues in general can not be a proper indicator for senescence.