Biomedical Research on Trace Elements
Online ISSN : 1880-1404
Print ISSN : 0916-717X
ISSN-L : 0916-717X
2020 31巻 3号
  • 玉野 春南, 武田 厚司
    原稿種別: 総説(2019年日本微量元素学会研究学術賞「浜理薬品賞」受賞講演の内容に基づく)
    2021 年 31 巻 3 号 p. 92-97
    発行日: 2021/03/09
    公開日: 2021/03/09
    ジャーナル フリー
    亜鉛は脳の発育、機能と密接に関係し、亜鉛摂取不足は行動異常の一因となる。脳内亜鉛の一部はZn2+として機能する。認知活動を司る海馬では、神経細胞内外のZn2+濃度はそれぞれ〜100 pMと〜10 nMである。細胞外Zn2+動態は認知機能とその低下の両方に関与し、細胞外グルタミン酸ならびにアルツハイマー病の原因物質と考えられているアミロイドβ1-42により大きな影響を受ける。海馬細胞外Zn2+濃度は加齢に伴い上昇する。上昇する原因は明らかでないが、この上昇により、神経細胞内Zn2+恒常性の破綻は容易となり、認知機能を低下させ、さらに神経を変性させる。したがって、神経細胞内Zn2+恒常性の破綻は加齢時の脳疾患のリスクファクターとなる。一方、細胞内Zn2+結合タンパク質であるメタロチオネインは細胞内Zn2+恒常性維持に重要であり、海馬の機能とも密接に関係する。本総説では、海馬におけるZn2+の機能と毒性に焦点を当て、これまでの研究を概説する。
  • Vladimir Zaichick
    原稿種別: Review Article
    2021 年 31 巻 3 号 p. 98-116
    発行日: 2021/03/09
    公開日: 2021/03/16
    ジャーナル フリー
    Background: In many studies it was found that the Zn level in prostatic tissue plays an important role in etiology benign prostate hypertrophy (BPH) and its measurement may be useful as a biomarker for differential diagnosis of hyperplastic and malignant transformations of gland. These findings promoted more detailed studies of the Zn content in the prostatic tissue of subjects with BPH.
    Method: The present study evaluated by systematic analysis the published data for Zn content analyzed in hyperplastic prostates as well as in normal glands. This evaluation reviewed 1885 studies, all of which were published in the years from 1921 to 2019 and were located by searching the databases Scopus, PubMed, MEDLINE, ELSEVIER-EMBASE, Cochrane Library, and the Web of Science. The articles were analyzed and “Median of Means” and “Range of Means” were used to examine heterogeneity of the measured Zn content in prostates of men with BPH and in prostates of apparently healthy adult subjects (control group). The objective analysis was performed on data from the 56 studies, with 1559 subjects for the BPH group and from the 97 studies, with 2985 subjects for the control group.
    Results: It was found that the range of means of prostatic Zn content reported in the literature varies widely: for hyperplastic gland from 11 mg/kg to 760 mg/kg with median of means 178 mg/kg and for normal prostates of adults from 17 mg/kg to 547 mg/kg with median of means 132 mg/kg on a wet mass basis. Ratios of means of Zn content in hyperplastic prostate (ZnBPH) to Zn content in normal gland (ZnN), obtained by the same authors and methods, were calculated. It was shown that the range of means of ZnBPH/ZnN ratio varies from 0.35 to 5.98 with median of means 1.38.
    Conclusion: Because of the uncertainties we have outlined, we recommend other primary studies should be performed.
  • 蜂須賀 英梨, 木戸 尊將, 須賀 万智, 柳澤 裕之
    原稿種別: Regular paper
    2021 年 31 巻 3 号 p. 117-125
    発行日: 2021/03/09
    公開日: 2021/03/16
    ジャーナル フリー
    Oral zinc supplementation corrects zinc deficiency and promotes good health. However, reports on zinc toxicity induced by excessive zinc ingestion remain limited. The aim of the present study was, therefore, to elucidate the effects of zinc excess on anemia. Over a 6-week period, one group of Sprague–Dawley rats was fed a standard diet containing 0.005% (w/w) zinc, whereas two other groups were fed a zinc excess diet including 0.2% (w/w) zinc, in which one group was intraperitoneally administered 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (tempol), a superoxide radical scavenger, for the final 8 days of the dietary duration. Blood samples were obtained and anemia-related parameters and oxidative stress markers were analyzed. An increase in red blood cell (RBC) osmotic fragility was observed, accompanied by microcytic hypochromic anemia, in the zinc excess group, which was restored to the standard group levels by tempol treatment. Additionally, a decrease in copper/zinc-superoxide dismutase (Cu/Zn-SOD) activity, a superoxide radical scavenger, was observed in the zinc excess groups, with an increase in the oxidative stress marker, 8-hydroxy-2'-deoxyguanosine, in the tempol-untreated zinc excess group. The relationship between the intestinal absorption rates of zinc and those of copper and iron was reciprocal. Thus, the microcytic hypochromic anemia may be, in part, owing to iron deficiency associated with zinc overload, whereas the increase in RBC osmotic fragility may be owing to oxidative stress derived from reduced Cu/Zn-SOD activity caused by copper deficiency associated with zinc overload.