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World J Gastroenterol. Jun 21, 2014; 20(23): 7298-7305
Published online Jun 21, 2014. doi: 10.3748/wjg.v20.i23.7298
Impairment of innate immune responses in cirrhotic patients and treatment by branched-chain amino acids
Ikuo Nakamura
Ikuo Nakamura, Department of Gastroenterology, Tokyo Medical University, Tokyo 160-0023, Japan
Ikuo Nakamura, Department of Gastroenterology, Saitama Medical Center, Jichi Medical University, Saitama 330-8503, Japan
Author contributions: Nakamura I solely contributed to this paper.
Supported by Grants (in part) from Ministry of Education, Culture, Sports, Science and Technology of Japan and the Ministry of Health, Labor and Welfare of Japan
Correspondence to: Ikuo Nakamura, MD, PhD, Department of Gastroenterology, Tokyo Medical University, 6-7-1, Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan. ikuonaka@tokyo-med.ac.jp
Telephone: +81-3-33426111 Fax: +81-3-53816654
Received: October 27, 2013
Revised: December 19, 2013
Accepted: April 30, 2014
Published online: June 21, 2014
Abstract

It has been reported that host defense responses, such as phagocytic function of neutrophils and natural killer (NK) cell activity of lymphocytes, are impaired in cirrhotic patients. This review will concentrate on the impairment of innate immune responses in decompensated cirrhotic patients and the effect of the treatment by branched-chain amino acids (BCAA) on innate immune responses. We already reported that phagocytic function of neutrophils was significantly improved by 3-mo BCAA supplementation. In addition, the changes of NK activity were also significant at 3 mo of supplementation compared with before supplementation. Also, Fisher’s ratios were reported to be significantly increased at 3 mo of BCAA supplementation compared with those before oral supplementation. Therefore, administration of BCAA could reduce the risk of bacterial and viral infection in patients with decompensated cirrhosis by restoring impaired innate immune responses of the host. In addition, it was also revealed that BCAA oral supplementation could reduce the risk of development of hepatocellular carcinoma in cirrhotic patients. The mechanisms of the effects will also be discussed in this review article.

Keywords: Branched-chain amino acids, Liver cirrhosis, Innate immunity, Natural killer cell activity of lymphocytes, Phagocytic function of neutrophils

Core tip: This review will discuss the recent research on impairment of innate immune responses in cirrhotic patients and the treatment by branched-chain amino acids (BCAA). It was revealed that BCAA oral supplementation could improve not only nutrition status but phagocytic function of neutrophils and natural killer activity of lymphocytes in cirrhotic patients. Therefore, BCAA supplementation might reduce the risk of bacterial and viral infection in patients with decompensated cirrhosis. Additionally, it was also revealed that BCAA oral supplementation could reduce the risk of development of hepatocellular carcinoma in cirrhotic patients. The mechanisms of the effects of BCAA described above will also be discussed.