Akikazu Takada

By Akikazu Takada, Fumiko Shimizu and Junichi Masuda

There are three pathways in tryptophan (TRP) metabolism. Serotonin (5-hydroxytryptamine; 5-HT) pathway is important in mood, anxiety, memory, and cognition and is impaired in depression. Kynurenine (KYN) pathways are involved in immunity, inflammation, muscles movement, and mental health. We investigated changes in TRP metabolites in plasmas of stressed rats and in depressive patients. TRP metabolite levels in 5-HT and KYN pathways in various brain areas and plasma were increased soon after electric foot shock given to rats but returned to normal 24 h later. Plasma levels of 5-HT were very low or undetectable in patients of monopolar depression. 5-hydroxyindole acetic acid (5-HIAA)/TRP ratios or KYN/TRP ratios were not different between healthy controls and depressive patients, indicating 5-HT quickly being degraded into 5-HIAA in patients of depression but KYN levels were not changed in depression. These results indicate that TRP metabolism changes upon stress application and in patients of depression.

Part of the book: Melatonin

By Akikazu Takada, Fumiko Shimizu and Shinji Koba

Omega and trans-fatty acids play important roles in atherogenesis of vascular system. In this review, we discuss such roles in health; there are much differences in coronary heart disease (CHD) rates between the US and Japan. Fatty acids profiles in the plasma are related to risks of CHD. There have been few studies that compared plasma levels of fatty acids, including trans-fatty acids, in people in Japan and the US. Plasma levels of long-chain omega-3 fatty acids (docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]) were higher in Japanese men, and omega-6 fatty acids (e.g., arachidonic acid [AA]) were lower compared with American men. American people had higher plasma levels of the major industrially produced trans-fatty acids (IP-TFAs; elaidic and inoelaidic acids), and levels of the potentially cardioprotective, primarily ruminant-derived trans-fatty acid, palmitoelaidic acid (POA) were higher in Japanese men. Plasma levels of saturated or monounsaturated fatty acids were also higher in American men. Only intakes of preference drinks have significant correlation with plasma levels of palmitoelaidic acid and linoelaidic acid. The higher levels of DHA and EPA, along with the lower levels of the IP-TFAs, are consistent with the markedly lower risk for coronary heart disease in Japan vs. the US.

Part of the book: Visions of Cardiomyocyte

By Hiroi Tomioka, Junichi Masuda, Akikazu Takada and Akira Iwanami

Plasma levels of tryptophan metabolites were compared between healthy volunteers and patients of major monopolar depression at various ages and genders. An ultrahigh-speed liquid chromatography/mass spectrometry has been used for analysis. There are significant gender and age differences in TRP metabolites of healthy volunteers. At the upper stream of metabolism, metabolites of young women and old men are higher, but at the lower stream of metabolism, their levels are higher in young men and old women. Such differences disappear in plasma of patients of major monopolar depression except for kynurenine (KYN). Daily variation of blood serotonin (5-HT) levels showed that 5-HT levels were low in the morning and increased toward evening, but blood levels of 5-HT were higher in healthy people than depressive people in the morning and decreased to ward evening. Significant age and gender differences of plasma levels of tryptophan metabolites in healthy volunteers disappear in patients of major monopolar depression. Blood levels of 5-HT were higher in healthy people than depressive patients.

Part of the book: Melatonin

By Akikazu Takada, Fumiko Shimizu, Yukie Ishii, Mutsumi Ogawa and Tetsuya Takao

It is not known whether the administration of glucose or sucrose influences plasma levels of amino acids. We want to know whether plasma levels of amino acids and if the administration of glucose or sucrose are different in young and old men and are influenced by the administration of glucose or sucrose. We found that the levels of most amino acids in plasma are lower in old men than young men. When sucrose was administered to old men, levels of total amino acids decreased significantly in old men. In both old and young men plasma levels of total nonessential amino acids significantly decreased at 120 min. after the administration of glucose but not sucrose. On the other hand, total essential and branched amino acids levels decreased significantly after the administration of both glucose and sucrose in young and old men. From these results, responses to the administration of glucose were different from the response to sucrose between young and old men. Also glucose was more effective in decreasing plasma levels of various amino acids. These results seem to suggest that glucose was more effective in stimulating insulin release and young men were more responsive to sugar than old men in stimulating insulin release.

Part of the book: New Insights Into Metabolic Syndrome

By Shinji Koba, Tetsuya Takao, Fumiko Shimizu, Mutsumi Ogawa, Yuuya Yokota, Fumiyoshi Tsunoda, Ken Arai, Toshiro Shinke and Akikazu Takada

Trans fatty acids (TFA) are found naturally in ruminant foods (R-TFA) by biohydrogenation in ruminant animals or industrially produced oils (IP-TFA) by partial hydrogenation of vegetable or fish oils. The intake of TFA mainly IP-TFA is associated with an elevated risk of coronary heart disease (CHD), while some prospective cohort studies showed that R-TFA were associated with a lower risk for sudden cardiac death (SCD). Our case-control study showed that trans-C18:2 isomers (IP-TFA) were significantly higher, and palmitelaidic acid (R-TFA) levels were lower in patients with acute coronary syndrome (ACS) compared with healthy men. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have different effects on cardiometabolic risk factors. Delta-5 desaturase (D5D) is a key enzyme in the conversion of linoleic acid and alpha-linoleneic acid to arachidonic acid (AA) and EPA, respectively. Previous studies reported that low D5D estimated from the ratio of AA to dihomo-gamma linolenic acid predicts the incident cardiovascular disease. In our cross-sectional study with 436 men with ACS, various atherogenic lipid markers such as small dense LDL cholesterol and malondialdehyde-modified LDL were significantly inversely associated with D5D activity. We found that the EPA/AA may be a superior risk marker than DHA/AA in terms of correlation with atherogenic lipid profiles.

Part of the book: New Insights Into Metabolic Syndrome