特刊名称: Impact of infections on the success of hematopoietic stem cell transplantations (感染对造血干细胞移植成功的影响) 期刊名称: Canadian Journal of Infectious Diseases and Medical Microbiology 客座主编: José Arellano-Galindo, 墨西哥城费德里科·戈麦斯儿童医院(Children Hospital of México Federico Gómez) 造血干细胞移植(HSCT)已成功用于白血病和其他血液系统恶性肿瘤的治疗,以及在实体器官肿瘤中接受高剂量化疗的患者的协助。除此之外,新的报告还描述了HSCT在HIV治疗中的用途。但是,进行HSCT需要免疫抑制条件,使患者处于细菌,真菌和病毒感染的风险中,从而使得这一治疗极具风险。患者还面临着尚未发现的微生物感染风险。另外,抗微生物疗法的选择有限,且取决于患者的危急状况。在这种情况下,HSCT患者的感染仍然具有较高的发病率和死亡率,这极大地影响了移植的成功率。 在本期特刊中,欢迎您提交相关文章,包括原创性研究文章、临床研究和高质量的评论,为患者提供更好的治疗方法 欢迎涉及以下领域的原创研究和综述论文投稿: 造血干细胞移植(HSCT)活动性感染和有症状感染的感染因子发病机理 用于诊断造血干细胞移植患者感染的新分子和免疫学方法以及基质辅助激光解吸电离飞行时间(MALDI-TOF)的优缺点 造血干细胞移植感染患者的新治疗方法 造血干细胞移植病毒感染的过继性治疗 接受造血干细胞移植的患者遇到的新病原体 造血干细胞移植抗微生物治疗后所出现的微生物、真菌或病毒耐药性 人类免疫缺陷病毒(HIV)领域的造血干细胞移植疗法 所有被接受的论文,均将根据 创作共用许可证 (Creative Commons Attribution License)进行出版。任何人均可免费获取您的论文,您将保留该论文的完整版权,这将确保您的研究将永远归属在您的名下。为此,所有经同行评审后被接受准备出版的论文,均应缴纳一次性文章处理费(APC)。 点击查看征稿详情 由查尔斯沃思集团(Charlesworth Group)统筹翻译。
饥饿(starvation)、禁食(fasting)、热量限制(calorie restriction)基本上表达了同一个意思,那就是指不会造成营养不良、更不会致人毙命的“忍饥挨饿”,这显然与古代“辟谷术”的不吃不喝完全不同,但似乎都对身体有好处,大概人类在进化过程中形成了随时随地应对饥荒的紧急响应机制,这让我们的古人可以“吃了上顿没下顿”地四处打猎寻找生计。 “少吃多动”对健康有益的看法已经成为人们的共识,而且知道热量限制的健康效应是长寿并减少慢性病发生,其机理是高效抗氧化损伤(保护染色体)和胞内自处理(如自噬)。但是,禁食对免疫系统究竟有什么特殊作用,人们却一直不知其详。 刚刚在《细胞——干细胞》(Cell Stem Cell)上发表的一篇最新论文指出,长期间歇禁食可以通过降低胰岛素样生长因子1(IGF-1)水平及减少蛋白激酶A(PKA)信号通路启动处于休眠状态的干细胞再生及自我更新进程,用以修复衰老和受损的免疫系统。将IGF-1或PKA撤除就能模拟禁食的效果,而添加IGF-1则能抵消禁食的效果。 这项研究不仅再次证明禁食有助于抗衰老和长寿,而且还能帮助癌症患者在化疗后迅速康复。若在化疗前禁食72小时,可以保护免疫细胞免遭放射线破坏。这个全新的结论与以往观念完全不同,通常认为化疗后应该加强营养才对,但这里却说应该禁食,而且要持续一段时间才行。 在小鼠及人体一期临床试验中,作者拟定的禁食方案是,一个周期持续6个月,每次禁食两到四天!这样的持续禁食才能唤醒休眠的造血干细胞,使之用再生的免疫细胞替换掉衰老而受损的免疫细胞。禁食既能消除免疫抑制,又能缓解免疫衰老。 饥饿的“代价”是饥肠辘辘,而饥饿的“回报”是病体康复!作为化疗后的肿瘤病人,请权衡一下禁食的代价与回报吧!不过,病人还是得在医生指导下方能实施。至于那些想长生不老的“欲成仙者”,则要想清楚牺牲口福、弥留人间值不值得。 以下是6月5日Science Daily发表的一篇相关新闻报道: Fasting triggers stem cell regeneration of damaged, old immune system Date: June 5, 2014 Source: University of Southern California Summary: In the first evidence of a natural intervention triggering stem cell-based regeneration of an organ or system, a study shows that cycles of prolonged fasting not only protect against immune system damage -- a major side effect of chemotherapy -- but also induce immune system regeneration, shifting stem cells from a dormant state to a state of self-renewal. During fasting the number of hematopoietic stem cells increases but the number of the normally much more abundant white blood cells decreases. In young or healthy mice undergoing multiple fasting/re-feeding cycles, the population of stem cells increases in size although the number of white blood cells remain normal. In mice treated with chemotherapy or in old mice, the cycles of fasting reverse the immunosuppression and immunosenescence, respectively. Credit: Cell Stem Cell, Cheng et al. In the first evidence of a natural intervention triggering stem cell-based regeneration of an organ or system, a study in the June 5 issue of the Cell Press journal Cell Stem Cell shows that cycles of prolonged fasting not only protect against immune system damage -- a major side effect of chemotherapy -- but also induce immune system regeneration, shifting stem cells from a dormant state to a state of self-renewal. In both mice and a Phase 1 human clinical trial, long periods of not eating significantly lowered white blood cell counts. In mice, fasting cycles then flipped a regenerative switch: changing the signaling pathways for hematopoietic stem cells, which are responsible for the generation of blood and immune systems, the research showed. The study has major implications for healthier aging, in which immune system decline contributes to increased susceptibility to disease as we age. By outlining how prolonged fasting cycles -- periods of no food for two to four days at a time over the course of six months -- kill older and damaged immune cells and generate new ones, the research also has implications for chemotherapy tolerance and for those with a wide range of immune system deficiencies, including autoimmunity disorders. We could not predict that prolonged fasting would have such a remarkable effect in promoting stem cell-based regeneration of the hematopoietic system, said corresponding author Valter Longo, the Edna M. Jones Professor of Gerontology and the Biological Sciences at the USC Davis School of Gerontology, and director of the USC Longevity Institute. When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of the immune cells that are not needed, especially those that may be damaged, Longo said. What we started noticing in both our human work and animal work is that the white blood cell count goes down with prolonged fasting. Then when you re-feed, the blood cells come back. So we started thinking, well, where does it come from? Prolonged fasting forces the body to use stores of glucose, fat and ketones, but also breaks down a significant portion of white blood cells. Longo likens the effect to lightening a plane of excess cargo. During each cycle of fasting, this depletion of white blood cells induces changes that trigger stem cell-based regeneration of new immune system cells. In particular, prolonged fasting reduced the enzyme PKA, an effect previously discovered by the Longo team to extend longevity in simple organisms and which has been linked in other research to the regulation of stem cell self-renewal and pluripotency -- that is, the potential for one cell to develop into many different cell types. Prolonged fasting also lowered levels of IGF-1, a growth-factor hormone that Longo and others have linked to aging, tumor progression and cancer risk. PKA is the key gene that needs to shut down in order for these stem cells to switch into regenerative mode. It gives the 'okay' for stem cells to go ahead and begin proliferating and rebuild the entire system, explained Longo, noting the potential of clinical applications that mimic the effects of prolonged fasting to rejuvenate the immune system. And the good news is that the body got rid of the parts of the system that might be damaged or old, the inefficient parts, during the fasting. Now, if you start with a system heavily damaged by chemotherapy or aging, fasting cycles can generate, literally, a new immune system. Prolonged fasting also protected against toxicity in a pilot clinical trial in which a small group of patients fasted for a 72-hour period prior to chemotherapy, extending Longo's influential past research: While chemotherapy saves lives, it causes significant collateral damage to the immune system. The results of this study suggest that fasting may mitigate some of the harmful effects of chemotherapy, said co-author Tanya Dorff, assistant professor of clinical medicine at the USC Norris Comprehensive Cancer Center and Hospital. More clinical studies are needed, and any such dietary intervention should be undertaken only under the guidance of a physician. We are investigating the possibility that these effects are applicable to many different systems and organs, not just the immune system, said Longo, whose lab is in the process of conducting further research on controlled dietary interventions and stem cell regeneration in both animal and clinical studies. Story Source: The above story is based on materials provided by University of Southern California . The original article was written by Suzanne Wu. Note: Materials may be edited for content and length. Journal Reference : Chia-Wei Cheng, Gregor B. Adams, Laura Perin, Min Wei, Xiaoying Zhou, Ben S. Lam, Stefano Da Sacco, Mario Mirisola, David I. Quinn, Tanya B. Dorff, John J. Kopchick, Valter D. Longo. Prolonged Fasting Reduces IGF-1/PKA to Promote Hematopoietic-Stem-Cell-Based Regeneration and Reverse Immunosuppression . Cell Stem Cell , 2014; 14 (6): 810 DOI: 10.1016/j.stem.2014.04.014