Osawa Yoshihiro, Mizushige Takafumi, Jinno Sayuri, Sugihara Fumihito, Inoue Naoki, Tanaka Hideyuki, Kabuyama Yukihito
United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology.
Faculty of Agriculture, Utsunomiya University.
Biomed Res. 2018;39(1):1-11. doi: 10.2220/biomedres.39.1.
A number of studies have shown that oral administration of collagen hydrolysate (CH) results in the absorption of di- and tri-peptides. In order to understand the dynamics of CH absorption and metabolism, molecular profiles of hydroxyproline (Hyp) and Hyp-containing peptides (HCPs) were analyzed by in situ perfusion of rat intestine and liver. The total amount of absorbed HCPs during 1 h of perfusion was 16.6 μmol, which was significantly higher than that of free Hyp (6.6 μmol). In addition, HCPs were also reliably detected in hepatic perfusate at the level higher than free Hyp. Thus, the results demonstrated that CH is absorbed predominantly as peptides, which subsequently enter systemic circulation. Size exclusion chromatography showed that perfusates include significant amount of HCPs larger than tripeptides, leading us to analyze these peptides in detail. Mass spectrometric analysis of intestinal perfusate finally identified three CH-derived peptides, which are surprisingly large as food-derived circulating peptides. Peptide quantitation by liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed that di- and tri-peptides, which are previously identified as major peptides in circulating blood, comprise only a part of HCPs in intestinal and liver perfusate. Finally, analysis of portal vein blood revealed that the larger peptides, such as pentadecapeptide identified in this study, could be absorbed in vivo. Taken all together, this study showed that peptides which are larger than tripeptide could reach to the circulation system after administration of CH, revealing previously unknown dynamics of absorption of CH.
多项研究表明，口服胶原蛋白水解物（CH）会导致二肽和三肽的吸收。为了了解CH吸收和代谢的动态过程，通过对大鼠肠道和肝脏进行原位灌注，分析了羟脯氨酸（Hyp）和含Hyp的肽（HCPs）的分子概况。灌注1小时期间吸收的HCPs总量为16.6μmol，显著高于游离Hyp的量（6.6μmol）。此外，在肝灌注液中也可靠地检测到了HCPs，其水平高于游离Hyp。因此，结果表明CH主要以肽的形式被吸收，随后进入体循环。尺寸排阻色谱显示，灌注液中包含大量大于三肽的HCPs，这促使我们对这些肽进行详细分析。对肠道灌注液的质谱分析最终鉴定出三种源自CH的肽，作为食物来源的循环肽，它们的大小惊人。通过液相色谱-串联质谱（LC-MS/MS）进行肽定量分析表明，先前被确定为循环血液中主要肽的二肽和三肽，仅占肠道和肝脏灌注液中HCPs的一部分。最后，对门静脉血的分析表明，本研究中鉴定出的较大肽，如十五肽，可以在体内被吸收。综上所述，本研究表明，给予CH后，大于三肽的肽可以到达循环系统，揭示了此前未知的CH吸收动态过程。
