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    Xin Zou, Ke Chen, Jiawei Zou, Peiyi Han, Jie Hao, Zeguang Han
    Frontiers of Medicine, 2020, 14(2): 185-192.

    It has been known that, the novel coronavirus, 2019-nCoV, which is considered similar to SARS-CoV, invades human cells via the receptor angiotensin converting enzyme II (ACE2). Moreover, lung cells that have ACE2 expression may be the main target cells during 2019-nCoV infection. However, some patients also exhibit non-respiratory symptoms, such as kidney failure, implying that 2019-nCoV could also invade other organs. To construct a risk map of different human organs, we analyzed the single-cell RNA sequencing (scRNA-seq) datasets derived from major human physiological systems, including the respiratory, cardiovascular, digestive, and urinary systems. Through scRNA-seq data analyses, we identified the organs at risk, such as lung, heart, esophagus, kidney, bladder, and ileum, and located specific cell types (i.e., type II alveolar cells (AT2), myocardial cells, proximal tubule cells of the kidney, ileum and esophagus epithelial cells, and bladder urothelial cells), which are vulnerable to 2019-nCoV infection. Based on the findings, we constructed a risk map indicating the vulnerability of different organs to 2019-nCoV infection. This study may provide potential clues for further investigation of the pathogenesis and route of 2019-nCoV infection.

    Jianping Ye
    Frontiers of Medicine, 2013, 7(1): 14-24.

    Obesity increases the risk for type 2 diabetes through induction of insulin resistance. Treatment of type 2 diabetes has been limited by little translational knowledge of insulin resistance although there have been several well-documented hypotheses for insulin resistance. In those hypotheses, inflammation, mitochondrial dysfunction, hyperinsulinemia and lipotoxicity have been the major concepts and have received a lot of attention. Oxidative stress, endoplasmic reticulum (ER) stress, genetic background, aging, fatty liver, hypoxia and lipodystrophy are active subjects in the study of these concepts. However, none of those concepts or views has led to an effective therapy for type 2 diabetes. The reason is that, there has been no consensus for a unifying mechanism of insulin resistance. In this review article, literature is critically analyzed and reinterpreted for a new energy-based concept of insulin resistance, in which insulin resistance is a result of energy surplus in cells. The energy surplus signal is mediated by ATP and sensed by adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. Decreasing ATP level by suppression of production or stimulation of utilization is a promising approach in the treatment of insulin resistance. In support, many of existing insulin sensitizing medicines inhibit ATP production in mitochondria. The effective therapies such as weight loss, exercise, and caloric restriction all reduce ATP in insulin sensitive cells. This new concept provides a unifying cellular and molecular mechanism of insulin resistance in obesity, which may apply to insulin resistance in aging and lipodystrophy.

    Yingjiang Zhou, Liangyou Rui
    Frontiers of Medicine, 2013, 7(2): 207-222.

    Leptin is secreted into the bloodstream by adipocytes and is required for the maintenance of energy homeostasis and body weight. Leptin deficiency or genetic defects in the components of the leptin signaling pathways cause obesity. Leptin controls energy balance and body weight mainly through leptin receptor b (LEPRb)-expressing neurons in the brain, particularly in the hypothalamus. These LEPRb-expressing neurons function as the first-order neurons that project to the second-order neurons located within and outside the hypothalamus, forming a neural network that controls the energy homeostasis and body weight. Multiple factors, including inflammation and endoplasmic reticulum (ER) stress, contribute to leptin resistance. Leptin resistance is the key risk factor for obesity. This review is focused on recent advance about leptin action, leptin signaling, and leptin resistance.

    Yun Zhang, Robert A. Weinberg
    Frontiers of Medicine, 2018, 12(4): 361-373.

    The cell-biological program termed the epithelial-to-mesenchymal transition (EMT) plays an important role in both development and cancer progression. Depending on the contextual signals and intracellular gene circuits of a particular cell, this program can drive fully epithelial cells to enter into a series of phenotypic states arrayed along the epithelial-mesenchymal phenotypic axis. These cell states display distinctive cellular characteristics, including stemness, invasiveness, drug-resistance and the ability to form metastases at distant organs, and thereby contribute to cancer metastasis and relapse. Currently we still lack a coherent overview of the molecular and biochemical mechanisms inducing cells to enter various states along the epithelial-mesenchymal phenotypic spectrum. An improved understanding of the dynamic and plastic nature of the EMT program has the potential to yield novel therapies targeting this cellular program that may aid in the management of high-grade malignancies.

    Min Zhou, Xinxin Zhang, Jieming Qu
    Frontiers of Medicine, 2020, 14(2): 126-135.

    Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has posed a significant threat to global health. It caused a total of 80 868 confirmed cases and 3101 deaths in Chinese mainland until March 8, 2020. This novel virus spread mainly through respiratory droplets and close contact. As disease progressed, a series of complications tend to develop, especially in critically ill patients. Pathological findings showed representative features of acute respiratory distress syndrome and involvement of multiple organs. Apart from supportive care, no specific treatment has been established for COVID-19. The efficacy of some promising antivirals, convalescent plasma transfusion, and tocilizumab needs to be investigated by ongoing clinical trials.

    Ranhua JIANG, Zhibo HAN, Guangsheng ZHUO, Xiaodan QU, Xue LI, Xin WANG, Yuankang SHAO, Shimin YANG, Zhong Chao HAN
    Frontiers of Medicine, 2011, 5(1): 94-100.

    Mesenchymal stem cells (MSC) have been used in clinical trials for severe diabetes, a chronic disease with high morbidity and mortality. Bone marrow is the traditional source of human MSC, but human term placenta appears to be an alternative and more readily available source. Here, the therapeutic effect of human placenta-derived MSC (PD-MSC) was studied in type 2 diabetes patients with longer duration, islet cell dysfunction, high insulin doses as well as poor glycemic control in order to evaluate the safety, efficacy and feasibility of PD-MSC treatment in type 2 diabetes (T2D). Ten patients with T2D received three intravenous infusions of PDSC, with one month interval of infusion. The total number of PDSC for each patient was (1.22–1.51) × 106/kg, with an average of 1.35 × 106/kg. All of the patients were followed up after therapy for at least 3 months. A daily mean dose of insulin used in 10 patients was decreased from 63.7?±?18.7 to 34.7?±?13.4 IU (P<0.01), and the C-peptide level was increased from 4.1?±?3.7 ng/mL to 5.6?±?3.8 ng/mL (P<0.05) respectively after therapy. In 4 of 10 responders their insulin doses reduced more than 50% after infusion. The mean levels of insulin and C-peptide at each time point in a total of 10 patients was higher after treatment (P<0.05). No fever, chills, liver damage and other side effects were reported. The renal function and cardiac function were improved after infusion. The results obtained from this pilot clinical trial indicate that transplantation of PD-MSC represents a simple, safe and effective therapeutic approach for T2D patients with islet cell dysfunction. Further large-scale, randomized and well-controlled clinical studies will be required to substantiate these observations.

    Wei Liu, Jing Wang, Wenbin Li, Zhaoxian Zhou, Siying Liu, Zhihui Rong
    Frontiers of Medicine, 2020, 14(2): 193-198.

    The aim of this study was to investigate the clinical characteristics of neonates born to SARS-CoV-2 infected mothers and increase the current knowledge on the perinatal consequences of COVID-19. Nineteen neonates were admitted to Tongji Hospital from January 31 to February 29, 2020. Their mothers were clinically diagnosed or laboratory-confirmed with COVID-19. We prospectively collected and analyzed data of mothers and infants. There are 19 neonates included in the research. Among them, 10 mothers were confirmed COVID-19 by positive SARS-CoV-2 RT-PCR in throat swab, and 9 mothers were clinically diagnosed with COVID-19. Delivery occurred in an isolation room and neonates were immediately separated from the mothers and isolated for at least 14 days. No fetal distress was found. Gestational age of the neonates was 38.6±1.5 weeks, and average birth weight was 3293±425 g. SARS-CoV-2 RT-PCR in throat swab, urine, and feces of all neonates were negative. SARS-CoV-2 RT-PCR in breast milk and amniotic fluid was negative too. None of the neonates developed clinical, radiologic, hematologic, or biochemical evidence of COVID-19. No vertical transmission of SARS-CoV-2 and no perinatal complications in the third trimester were found in our study. The delivery should occur in isolation and neonates should be separated from the infected mothers and care givers.

    Elena Chung, Guo Chen, Brenton Alexander, Maxime Cannesson
    Frontiers of Medicine, 2013, 7(1): 91-101.

    Blood pressure monitoring has come a long way from the initial observations made by Reverend Hales in the 18th century. There are none that deny the importance of monitoring perioperative blood pressure; however, the limited ability of the current prevalent technology (oscillometric blood pressure monitoring) to offer continuous blood pressure measurements leaves room for improvement. Invasive monitoring is able to detect beat-to-beat blood pressure measurement, but the risks inherent to the procedure make it unsuitable for routine use except when this risk is outweighed by the benefits. This review focuses on the discoveries which have led up to the current blood pressure monitoring technologies, and especially the creation of those offering non-invasive but continuous blood pressure monitoring capabilities, including their methods of measurement and limitations.

    Yongping Zhang, Xingying Zhang, Chen Cheng, Wei Mu, Xiaojuan Liu, Na Li, Xiaofei Wei, Xiang Liu, Changqing Xia, Haoyi Wang
    Frontiers of Medicine, 2017, 11(4): 554-562.

    T cells engineered with chimeric antigen receptor (CAR) have been successfully applied to treat advanced refractory B cell malignancy. However, many challenges remain in extending its application toward the treatment of solid tumors. The immunosuppressive nature of tumor microenvironment is considered one of the key factors limiting CAR-T efficacy. One negative regulator of T cell activity is lymphocyte activation gene-3 (LAG-3). We successfully generated LAG-3 knockout T and CAR-T cells with high efficiency using CRISPR-Cas9 mediated gene editing and found that the viability and immune phenotype were not dramatically changed during in vitro culture. LAG-3 knockout CAR-T cells displayed robust antigen-specific antitumor activity in cell culture and in murine xenograft model, which is comparable to standard CAR-T cells. Our study demonstrates an efficient approach to silence immune checkpoint in CAR-T cells via gene editing.

    Xiao Miao, Weixia Sun, Yaowen Fu, Lining Miao, Lu Cai
    Frontiers of Medicine, 2013, 7(1): 31-52.

    Zinc (Zn) is an essential mineral that is required for various cellular functions. Zn dyshomeostasis always is related to certain disorders such as metabolic syndrome, diabetes and diabetic complications. The associations of Zn with metabolic syndrome, diabetes and diabetic complications, thus, stem from the multiple roles of Zn: (1) a constructive component of many important enzymes or proteins, (2) a requirement for insulin storage and secretion, (3) a direct or indirect antioxidant action, and (4) an insulin-like action. However, whether there is a clear cause-and-effect relationship of Zn with metabolic syndrome, diabetes, or diabetic complications remains unclear. In fact, it is known that Zn deficiency is a common phenomenon in diabetic patients. Chronic low intake of Zn was associated with the increased risk of diabetes and diabetes also impairs Zn metabolism. Theoretically Zn supplementation should prevent the metabolic syndrome, diabetes, and diabetic complications; however, limited available data are not always supportive of the above notion. Therefore, this review has tried to summarize these pieces of available information, possible mechanisms by which Zn prevents the metabolic syndrome, diabetes, and diabetic complications. In the final part, what are the current issues for Zn supplementation were also discussed.

    Zhengqian Li, Taotao Liu, Ning Yang, Dengyang Han, Xinning Mi, Yue Li, Kaixi Liu, Alain Vuylsteke, Hongbing Xiang, Xiangyang Guo
    Frontiers of Medicine, 2020, 14(5): 533-541.

    Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a global pandemic in only 3 months. In addition to major respiratory distress, characteristic neurological manifestations are also described, indicating that SARS-CoV-2 may be an underestimated opportunistic pathogen of the brain. Based on previous studies of neuroinvasive human respiratory coronaviruses, it is proposed that after physical contact with the nasal mucosa, laryngopharynx, trachea, lower respiratory tract, alveoli epithelium, or gastrointestinal mucosa, SARS-CoV-2 can induce intrinsic and innate immune responses in the host involving increased cytokine release, tissue damage, and high neurosusceptibility to COVID-19, especially in the hypoxic conditions caused by lung injury. In some immune-compromised individuals, the virus may invade the brain through multiple routes, such as the vasculature and peripheral nerves. Therefore, in addition to drug treatments, such as pharmaceuticals and traditional Chinese medicine, non-pharmaceutical precautions, including facemasks and hand hygiene, are critically important.

    Jingyi Lu, Guoxiang Xie, Weiping Jia, Wei Jia
    Frontiers of Medicine, 2013, 7(1): 53-59.

    Insulin resistance (IR) is a key pathological feature of metabolic syndrome and subsequently causes serious health problems with an increased risk of several common metabolic disorders. IR related metabolic disturbance is not restricted to carbohydrates but impacts global metabolic network. Branched-chain amino acids (BCAAs), namely valine, leucine and isoleucine, are among the nine essential amino acids, accounting for 35% of the essential amino acids in muscle proteins and 40% of the preformed amino acids required by mammals. The BCAAs are particularly responsive to the inhibitory insulin action on amino acid release by skeletal muscle and their metabolism is profoundly altered in insulin resistant conditions and/or insulin deficiency. Although increased circulating BCAA concentration in insulin resistant conditions has been noted for many years and BCAAs have been reported to be involved in the regulation of glucose homeostasis and body weight, it is only recently that BCAAs are found to be closely associated with IR. This review will focus on the recent findings on BCAAs from both epidemic and mechanistic studies.

    Feng Ye, Adam K. Snider, Mark H. Ginsberg
    Frontiers of Medicine, 2014, 8(1): 6-16.

    Proper cell-cell and cell-matrix contacts mediated by integrin adhesion receptors are important for development, immune response, hemostasis and wound healing. Integrins pass trans-membrane signals bidirectionally through their regulated affinities for extracellular ligands and intracellular signaling molecules. Such bidirectional signaling by integrins is enabled by the conformational changes that are often linked among extracellular, transmembrane and cytoplasmic domains. Here, we review how talin-integrin and kindlin-integrin interactions, in cooperation with talin-lipid and kindlin-lipid interactions, regulate integrin affinities and how the progress in these areas helps us understand integrin-related diseases.

    Jiyu Tong, Richard A. Flavell, Hua-Bing Li
    Frontiers of Medicine, 2018, 12(4): 481-489.

    N6-methyladenosine (m6A) is the most common post-transcriptional RNA modification throughout the transcriptome, affecting fundamental aspects of RNA metabolism. m6A modification could be installed by m6A “writers” composed of core catalytic components (METTL3/METTL14/WTAP) and newly defined regulators and removed by m6A “erasers” (FTO and ALKBH5). The function of m6A is executed by m6A “readers” that bind to m6A directly (YTH domain-containing proteins, eIF3 and IGF2BPs) or indirectly (HNRNPA2B1). In the past few years, advances in m6A modulators (“writers,” “erasers,” and “readers”) have remarkably renewed our understanding of the function and regulation of m6A in different cells under normal or disease conditions. However, the mechanism and the regulatory network of m6A are still largely unknown. Moreover, investigations of the m6A physiological roles in human diseases are limited. In this review, we summarize the recent advances in m6A research and highlight the functional relevance and importance of m6A modification in in vitro cell lines, in physiological contexts, and in cancers.

    Patrick A. Carroll, Brian W. Freie, Haritha Mathsyaraja, Robert N. Eisenman
    Frontiers of Medicine, 2018, 12(4): 412-425.

    Transcription factor networks have evolved in order to control, coordinate, and separate, the functions of distinct network modules spatially and temporally. In this review we focus on the MYC network (also known as the MAX-MLX Network), a highly conserved super-family of related basic-helix-loop-helix-zipper (bHLHZ) proteins that functions to integrate extracellular and intracellular signals and modulate global gene expression. Importantly the MYC network has been shown to be deeply involved in a broad spectrum of human and other animal cancers. Here we summarize molecular and biological properties of the network modules with emphasis on functional interactions among network members. We suggest that these network interactions serve to modulate growth and metabolism at the transcriptional level in order to balance nutrient demand with supply, to maintain growth homeostasis, and to influence cell fate. Moreover, oncogenic activation of MYC and/or loss of a MYC antagonist, results in an imbalance in the activity of the network as a whole, leading to tumor initiation, progression and maintenance.

    Kyoung-Woong Kim, Penradee Chanpiwat, Hoang Thi Hanh, Kongkea Phan, Suthipong Sthiannopkao
    Frontiers of Medicine, 2011, 5(4): 420-433.

    The occurrence of high concentrations of arsenic in the groundwater of the Southeast Asia region has received much attention in the past decade. This study presents an overview of the arsenic contamination problems in Vietnam, Cambodia, Lao People’s Democratic Republic and Thailand. Most groundwater used as a source of drinking water in rural areas has been found to be contaminated with arsenic exceeding the WHO drinking water guideline of 10 μg·L-1. With the exception of Thailand, groundwater was found to be contaminated with naturally occurring arsenic in the region. Interestingly, high arsenic concentrations (>10 μg·L-1) were generally found in the floodplain areas located along the Mekong River. The source of elevated arsenic concentrations in groundwater is thought to be the release of arsenic from river sediments under highly reducing conditions. In Thailand, arsenic has never been found naturally in groundwater, but originates from tin mining activities. More than 10 million residents in Southeast Asia are estimated to be at risk from consuming arsenic-contaminated groundwater. In Southeast Asia, groundwater has been found to be a significant source of daily inorganic arsenic intake in humans. A positive correlation between groundwater arsenic concentration and arsenic concentration in human hair has been observed in Cambodia and Vietnam. A substantial knowledge gap exists between the epidemiology of arsenicosis and its impact on human health. More collaborative studies particularly on the scope of public health and its epidemiology are needed to conduct to fulfill the knowledge gaps of As as well as to enhance the operational responses to As issue in Southeast Asian countries.

    Chuanfeng Wu, Cynthia E. Dunbar
    Frontiers of Medicine, 2011, 5(4): 356-371.

    Virus-based vectors are widely used in hematopoietic stem cell (HSC) gene therapy, and have the ability to integrate permanently into genomic DNA, thus driving long-term expression of corrective genes in all hematopoietic lineages. To date, HSC gene therapy has been successfully employed in the clinic for improving clinical outcomes in small numbers of patients with X-linked severe combined immunodeficiency (SCID-X1), adenosine deaminase deficiency (ADA-SCID), adrenoleukodystrophy (ALD), thalassemia, chronic granulomatous disease (CGD), and Wiskott-Aldrich syndrome (WAS). However, adverse events were observed during some of these HSC gene therapy clinical trials, linked to insertional activation of proto-oncogenes by integrated proviral vectors leading to clonal expansion and eventual development of leukemia. Numerous studies have been performed to understand the molecular basis of vector-mediated genotoxicity, with the aim of developing safer vectors and lower-risk gene therapy protocols. This review will summarize current information on the mechanisms of insertional mutagenesis in hematopoietic stem and progenitor cells due to integrating gene transfer vectors, discuss the available assays for predicting genotoxicity and mapping vector integration sites, and introduce newly-developed approaches for minimizing genotoxicity as a way to further move HSC gene therapy forward into broader clinical application.

    Wenbo Yan, Xin Li
    Frontiers of Medicine, 2013, 7(1): 81-90.

    Diabetes mellitus is an enormous menace to public health globally. This chronic disease of metabolism will adversely affect the skeleton if not controlled. Both type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) are associated with an increased risk of osteoporosis and fragility fractures. Bone mineral density is reduced in T1DM, whereas patients with T2DM have normal or slightly higher bone density, suggesting impaired bone quality is involved. Detrimental effects of T1DM on the skeleton are more severe than T2DM, probably because of the lack of osteo-anabolic effects of insulin and other pancreatic hormones. In both T1DM and T2DM, low bone quality could be caused by various means, including but not limited to hyperglycemia, accumulation of advanced glycosylation end products (AGEs), decreased serum levels of osteocalcin and parathyroid hormone. Risk for osteoarthritis is also elevated in diabetic population. How diabetes accelerates the deterioration of cartilage remains largely unknown. Hyperglycemia and glucose derived AGEs could contribute to the development of osteoarthritis. Moreover, it is recognized that oral antidiabetic medicines affect bone metabolism and turnover as well. Insulin is shown to have anabolic effects on bone and hyperinsulinemia may help to explain the slightly higher bone density in patients with T2DM. Thiazolidinediones can promote bone loss and osteoporotic fractures by suppressing osteoblastogenesis and enhancing osteoclastogenesis. Metformin favors bone formation by stimulating osteoblast differentiation and protecting them against diabetic conditions such as hyperglycemia. Better knowledge of how diabetic conditions and its treatments influence skeletal tissues is in great need in view of the growing and aging population of patients with diabetes mellitus.

    Beicheng Sun, Michael Karin
    Frontiers of Medicine, 2013, 7(2): 242-254.

    Inflammation has been considered as one of the hallmarks of cancer, and chronic hepatitis is a major cause of liver cancer. This review will focus on the pathogenic role of inflammation in hepatocarcinogenesis and will discuss recent advances in understanding the chronic hepatitis-liver cancer link based on hot spots in liver cancer research, including cellular interaction, cytokines, microRNA and stem cells. All of these mechanisms should be taken into consideration because they are crucial for the development of more efficacious therapeutic strategies for preventing and treating human chronic hepatitis and hepatocellular carcinoma.

    Eun Young Lee, Kun-Ho Yoon
    Frontiers of Medicine, 2018, 12(6): 658-666.

    The prevalence of obesity among children and adolescents (aged 2–18 years) has increased rapidly, with more than 100 million affected in 2015. Moreover, the epidemic of obesity in this population has been an important public health problem in developed and developing countries for the following reasons. Childhood and adolescent obesity tracks adulthood obesity and has been implicated in many chronic diseases, including type 2 diabetes, hypertension, and cardiovascular disease. Furthermore, childhood and adolescent obesity is linked to adulthood mortality and premature death. Although an imbalance between caloric intake and physical activity is a principal cause of childhood and adolescent obesity, environmental factors are exclusively important for development of obesity among children and adolescents. In addition to genetic and biological factors, socioenvironmental factors, including family, school, community, and national policies, can play a crucial role. The complexity of risk factors for developing obesity among children and adolescents leads to difficulty in treatment for this population. Many interventional trials for childhood and adolescent obesity have been proven ineffective. Therefore, early identification and prevention is the key to control the global epidemic of obesity. Given that the proportion of overweight children and adolescents is far greater than that of obesity, an effective prevention strategy is to focus on overweight youth, who are at high risk for developing obesity. Multifaceted, comprehensive strategies involving behavioral, psychological, and environmental risk factors must also be developed to prevent obesity among children and adolescents.

    Li Ni, Ling Zhou, Min Zhou, Jianping Zhao, Dao Wen Wang
    Frontiers of Medicine, 2020, 14(2): 210-214.

    In December 2019, an outbreak of novel coronavirus (2019-nCoV) occurred in Wuhan, Hubei Province, China. By February 14, 2020, it has led to 66 492 confirmed patients in China and high mortality up to ~2.96% (1123/37 914) in Wuhan. Here we report the first family case of coronavirus disease 2019 (COVID-19) confirmed in Wuhan and treated using the combination of western medicine and Chinese traditional patent medicine Shuanghuanglian oral liquid (SHL). This report describes the identification, diagnosis, clinical course, and management of three cases from a family, suggests the expected therapeutic effects of SHL on COVID-19, and warrants further clinical trials.

    Junyun Wang, Shuang Chang, Guochao Li, Yingli Sun
    Frontiers of Medicine, 2017, 11(4): 522-527.

    Precision medicine for cancer patients aims to adopt the most suitable treatment options during diagnosis and treatment of individuals. Detecting circulating tumor cell (CTC) or circulating tumor DNA (ctDNA) in plasma or serum could serve as liquid biopsy, which would be useful for numerous diagnostic applications. Liquid biopsies can help clinicians screen and detect cancer early, stratify patients to the most suitable treatment and real-time monitoring of treatment response and resistance mechanisms in the tumor, evaluate the risk for metastatic relapse, and estimate prognosis. We summarized the advantages and disadvantages of tissue and liquid biopsies. We also further compared and analyzed the advantages and limitations of detecting CTCs, ctDNAs, and exosomes. Furthermore, we reviewed the literature related with the application of serum or plasma CTCs, ctDNAs, and exosomes for diagnosis and prognosis of cancer. We also analyzed their opportunities and challenges as future biomarkers. In the future, liquid biopsies could be used to guide cancer treatment. They could also provide the ideal scheme to personalize treatment in precision medicine.

    Li LI, Jianxin JIANG
    Frontiers of Medicine, 2011, 5(1): 33-39.

    Adult stem cells hold great promise for wound healing and tissue regeneration. Mesenchymal stem cells (MSCs), for example, have been shown to play a role in tissue repair. Research has shown that endogenous bone marrow MSCs or exogenously delivered MSCs migrate to the sites of injury and participate in the repair process. The precise mechanisms underlying migration of MSCs into the injured tissue are still not fully understood, although multiple signaling pathways and molecules were reported, including both chemoattractive factors and endogenous electric fields at wounds. This review will briefly summarize the regulatory facors and signaling transduction pathways involved in migration of MSCs. A better understanding of the molecular mechanisms involved in the migration of MSCs will help us to develop new stem cell-based therapeutic strategies in regenerative medicine.

    Suchinda Malaivijitnond
    Frontiers of Medicine, 2012, 6(1): 8-21.

    Pueraria mirifica Airy Shaw et Suvatabandhu is a medicinal plant endemic to Thailand. It has been used in Thai folklore medicine for its rejuvenating qualities in aged women and men for nearly one hundred years. Indeed, it has been claimed that P. mirifica contains active phytoestrogens (plant substances with estrogen-like activity). Using high performance liquid chromatography, at least 17 phytoestrogens, mainly isoflavones, have been isolated. Thus, fairly considerable scientific researches, both in vitro in cell lines and in vivo in various species of animals including humans, have been conducted to date to address its estrogenic activity on the reproductive organs, bones, cardiovascular diseases and other climacteric related symptoms. The antioxidative capacity and antiproliferative effect on tumor cell lines have also been assessed. In general, P. mirifica could be applicable for preventing, or as a therapeutic for, the symptoms related to estrogen deficiency in menopausal women as well as in andropausal men. However, the optimal doses for each desirable effect and the balance to avoid undesired side effects need to be calculated before use.

    Zhifeng Wang, Fengli Wang, Tieshan Tang, Caixia Guo
    Frontiers of Medicine, 2012, 6(2): 156-164.

    Single-strand break repair protein poly(ADP-ribose) polymerase 1 (PARP1) catalyzes the poly(ADP-ribosyl)ation of many key proteins in vivo and thus plays important roles in multiple DNA damage response pathways, rendering it a promising target in cancer therapy. The tumor-suppressor effects of PARP inhibitors have attracted significant interest for development of novel cancer therapies. However, recent evidence indicated that the underlying mechanism of PARP inhibitors in tumor therapy is more complex than previously expected. The present review will focus on recent progress on the role of PARP1 in the DNA damage response and PARP inhibitors in cancer therapy. The emerging resistance of BRCA-deficient tumors to PARP inhibitors is also briefly discussed from the perspective of DNA damage and repair. These recent research advances will inform the selection of patient populations who can benefit from the PARP inhibitor treatment and development of effective drug combination strategies.

    Shihua Wang, Xuebin Qu, Robert Chunhua Zhao
    Frontiers of Medicine, 2011, 5(4): 372-378.

    Regenerative medicine is an emerging interdisciplinary field of research that uses several technological approaches including stem cells to repair tissues. Mesenchymal stem cells (MSCs), a type of adult stem cell, have generated a great amount of interest over the past decade in this field. Numerous studies have explored the role of MSCs in tissue repair and modulation of allogeneic immune responses. The mechanisms through which MSCs exert their therapeutic potential rely on some key properties of the cells as follows: the capacity to differentiate into osteoblasts, chondrocytes, adipocytes, cardiomyocytes, hepatocytes, endothelial, and neuronal cells; the ability to secrete multiple bioactive molecules capable of stimulating the recovery of injured cells and inhibiting inflammation; the lack of immunogenicity; and the ability to perform immunomodulatory functions. In the present review, we focus on these three aspects upon which the therapeutic effects of MSCs are mainly based. Furthermore, some pathological conditions under which the application of MSCs should be done with caution are also mentioned.

    Huimin Gao, Zhimin Wang, Yujuan Li, Zhongzhi Qian
    Frontiers of Medicine, 2011, 5(2): 195-202.

    Traditional Chinese medicine (TCM) has been widely used for the prevention and treatment of various diseases for a long time in China. Due to its proven efficacy, wide applications, and low side effect, TCM has increasingly attracted worldwide attention. However, one of the biggest challenges facing the clinical practice of TCM is the uncontrollable quality. In this review, the progress of the development and the current status of quality standard as well as new quality control techniques introduced in Chinese Pharmacopoeia (2010 edition), such as liquid chromatography hyphenated mass spectrometry (LC-MS), fingerprint, quantitative analysis of multi-components by single-marker (QAMS), thin layer chromatography bio-autographic assay (TLC-BAA), and DNA molecular marker technique, are briefly overviewed.

    Megan A. Hatlen, Lan Wang, Stephen D. Nimer
    Frontiers of Medicine, 2012, 6(3): 248-262.

    The AML1-ETO fusion transcription factor is generated by the t(8;21) translocation, which is present in approximately 4%–12% of adult and 12%–30% of pediatric acute myeloid leukemia (AML) patients. Both human and mouse models of AML have demonstrated that AML1-ETO is insufficient for leukemogenesis in the absence of secondary events. In this review, we discuss the pathogenetic insights that have been gained from identifying the various events that can cooperate with AML1-ETO to induce AML in vivo. We also discuss potential therapeutic strategies for t(8;21) positive AML that involve targeting the fusion protein itself, the proteins that bind to it, or the genes that it regulates. Recently published studies suggest that a targeted therapy for t(8;21) positive AML is feasible and may be coming sometime soon.

    Juan Zheng,Shih-Lung Woo,Xiang Hu,Rachel Botchlett,Lulu Chen,Yuqing Huo,Chaodong Wu
    Frontiers of Medicine, 2015, 9(2): 173-186.

    Metformin has been widely used as a first-line anti-diabetic medicine for the treatment of type 2 diabetes (T2D). As a drug that primarily targets the liver, metformin suppresses hepatic glucose production (HGP), serving as the main mechanism by which metformin improves hyperglycemia of T2D. Biochemically, metformin suppresses gluconeogenesis and stimulates glycolysis. Metformin also inhibits glycogenolysis, which is a pathway that critically contributes to elevated HGP. While generating beneficial effects on hyperglycemia, metformin also improves insulin resistance and corrects dyslipidemia in patients with T2D. These beneficial effects of metformin implicate a role for metformin in managing non-alcoholic fatty liver disease. As supported by the results from both human and animal studies, metformin improves hepatic steatosis and suppresses liver inflammation. Mechanistically, the beneficial effects of metformin on hepatic aspects are mediated through both adenosine monophosphate-activated protein kinase (AMPK)-dependent and AMPK-independent pathways. In addition, metformin is generally safe and may also benefit patients with other chronic liver diseases.

    Carmen Chak-Lui Wong, Alan Ka-Lun Kai, Irene Oi-Lin Ng
    Frontiers of Medicine, 2014, 8(1): 33-41.

    Hypoxia is a common phenomenon in hepatocellular carcinoma (HCC). Hypoxia stabilizes transcription factor, hypoxia-inducible factor (HIF), to activate gene transcription. Expression of HIF is closely associated with metastasis and poor prognosis in HCC. HIF mediates expression of genes that are involved in every step of HCC metastasis including epithelial-mesenchymal transition, invasion of the extracellular matrix, intravasation, extravasation, and secondar y growth of the metastases. Because HIF is the central regulator of HCC metastasis, HIF inhibitors are attractive tools when used alone or as combined treatment to curb HCC metastasis. This review will summarize the current findings on the impact of hypoxia/HIF in HCC, with a particular focus on cancer metastasis.