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  • RESEARCH ARTICLE
    Xin Zou, Ke Chen, Jiawei Zou, Peiyi Han, Jie Hao, Zeguang Han
    Frontiers of Medicine, 2020, 14(2): 185-192. https://doi.org/10.1007/s11684-020-0754-0

    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.

  • REVIEW
    Jianping Ye
    Frontiers of Medicine, 2013, 7(1): 14-24. https://doi.org/10.1007/s11684-013-0262-6

    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.

  • RESEARCH ARTICLE
    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. https://doi.org/10.1007/s11684-011-0116-z

    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.

  • REVIEW
    Min Zhou, Xinxin Zhang, Jieming Qu
    Frontiers of Medicine, 2020, 14(2): 126-135. https://doi.org/10.1007/s11684-020-0767-8

    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.

  • REVIEW
    Eun Young Lee, Kun-Ho Yoon
    Frontiers of Medicine, 2018, 12(6): 658-666. https://doi.org/10.1007/s11684-018-0640-1

    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.

  • REVIEW
    Yingjiang Zhou, Liangyou Rui
    Frontiers of Medicine, 2013, 7(2): 207-222. https://doi.org/10.1007/s11684-013-0263-5

    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.

  • REVIEW
    Jiyu Tong, Richard A. Flavell, Hua-Bing Li
    Frontiers of Medicine, 2018, 12(4): 481-489. https://doi.org/10.1007/s11684-018-0654-8

    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.

  • REVIEW
    Pengju Zhang, Tao Li, Xingyun Wu, Edouard C. Nice, Canhua Huang, Yuanyuan Zhang
    Frontiers of Medicine, 2020, 14(5): 583-600. https://doi.org/10.1007/s11684-019-0729-1

    Diabetes mellitus is one of the major public health problems worldwide. Considerable recent evidence suggests that the cellular reduction–oxidation (redox) imbalance leads to oxidative stress and subsequent occurrence and development of diabetes and related complications by regulating certain signaling pathways involved in β-cell dysfunction and insulin resistance. Reactive oxide species (ROS) can also directly oxidize certain proteins (defined as redox modification) involved in the diabetes process. There are a number of potential problems in the clinical application of antioxidant therapies including poor solubility, storage instability and non-selectivity of antioxidants. Novel antioxidant delivery systems may overcome pharmacokinetic and stability problem and improve the selectivity of scavenging ROS. We have therefore focused on the role of oxidative stress and antioxidative therapies in the pathogenesis of diabetes mellitus. Precise therapeutic interventions against ROS and downstream targets are now possible and provide important new insights into the treatment of diabetes.

  • REVIEW
    Min Chen, Yuan Xu, Nan Hong, Yali Yang, Wenzhi Lei, Lin Du, Jingjun Zhao, Xia Lei, Lin Xiong, Langqi Cai, Hui Xu, Weihua Pan, Wanqing Liao
    Frontiers of Medicine, 2018, 12(1): 58-75. https://doi.org/10.1007/s11684-017-0601-0

    With the increasing number of immunocompromised hosts, the epidemiological characteristics of fungal infections have undergone enormous changes worldwide, including in China. In this paper, we reviewed the existing data on mycosis across China to summarize available epidemiological profiles. We found that the general incidence of superficial fungal infections in China has been stable, but the incidence of tinea capitis has decreased and the transmission route has changed. By contrast, the overall incidence of invasive fungal infections has continued to rise. The occurrence of candidemia caused by Candida species other than C. albicans and including some uncommon Candida species has increased recently in China. Infections caused by Aspergillus have also propagated in recent years, particularly with the emergence of azole-resistant Aspergillus fumigatus. An increasing trend of cryptococcosis has been noted in China, with Cryptococcus neoformans var. grubii ST 5 genotype isolates as the predominant pathogen. Retrospective studies have suggested that the epidemiological characteristics of Pneumocystis pneumonia in China may be similar to those in other developing countries. Endemic fungal infections, such as sporotrichosis in Northeastern China, must arouse research, diagnostic, and treatment vigilance. Currently, the epidemiological data on mycosis in China are variable and fragmentary. Thus, a nationwide epidemiological research on fungal infections in China is an important need for improving the country’s health.

  • REVIEW
    Kohei Miyazono, Yoko Katsuno, Daizo Koinuma, Shogo Ehata, Masato Morikawa
    Frontiers of Medicine, 2018, 12(4): 387-411. https://doi.org/10.1007/s11684-018-0646-8

    Transforming growth factor (TGF)-β regulates a wide variety of cellular responses, including cell growth arrest, apoptosis, cell differentiation, motility, invasion, extracellular matrix production, tissue fibrosis, angiogenesis, and immune function. Although tumor-suppressive roles of TGF-β have been extensively studied and well-characterized in many cancers, especially at early stages, accumulating evidence has revealed the critical roles of TGF-β as a pro-tumorigenic factor in various types of cancer. This review will focus on recent findings regarding epithelial-mesenchymal transition (EMT) induced by TGF-β, in relation to crosstalk with some other signaling pathways, and the roles of TGF-β in lung and pancreatic cancers, in which TGF-β has been shown to be involved in cancer progression. Recent findings also strongly suggested that targeting TGF-β signaling using specific inhibitors may be useful for the treatment of some cancers. TGF-β plays a pivotal role in the differentiation and function of regulatory T cells (Tregs). TGF-β is produced as latent high molecular weight complexes, and the latent TGF-β complex expressed on the surface of Tregs contains glycoprotein A repetitions predominant (GARP, also known as leucine-rich repeat containing 32 or LRRC32). Inhibition of the TGF-β activities through regulation of the latent TGF-β complex activation will be discussed.

  • REVIEW
    Xiao Miao, Weixia Sun, Yaowen Fu, Lining Miao, Lu Cai
    Frontiers of Medicine, 2013, 7(1): 31-52. https://doi.org/10.1007/s11684-013-0251-9

    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.

  • REVIEW
    Kyoung-Woong Kim, Penradee Chanpiwat, Hoang Thi Hanh, Kongkea Phan, Suthipong Sthiannopkao
    Frontiers of Medicine, 0: 420-433. https://doi.org/10.1007/s11684-011-0158-2

    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.

  • RESEARCH ARTICLE
    Wei Liu, Jing Wang, Wenbin Li, Zhaoxian Zhou, Siying Liu, Zhihui Rong
    Frontiers of Medicine, 2020, 14(2): 193-198. https://doi.org/10.1007/s11684-020-0772-y

    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.

  • REVIEW
    Shujian Deng, Xin Zhang, Wen Yan, Eric I-Chao Chang, Yubo Fan, Maode Lai, Yan Xu
    Frontiers of Medicine, 2020, 14(4): 470-487. https://doi.org/10.1007/s11684-020-0782-9

    deep learning (DL) has achieved state-of-the-art performance in many digital pathology analysis tasks. Traditional methods usually require hand-crafted domain-specific features, and DL methods can learn representations without manually designed features. In terms of feature extraction, DL approaches are less labor intensive compared with conventional machine learning methods. In this paper, we comprehensively summarize recent DL-based image analysis studies in histopathology, including different tasks (e.g., classification, semantic segmentation, detection, and instance segmentation) and various applications (e.g., stain normalization, cell/gland/region structure analysis). DL methods can provide consistent and accurate outcomes. DL is a promising tool to assist pathologists in clinical diagnosis.

  • REVIEW
    Feng Ye, Adam K. Snider, Mark H. Ginsberg
    Frontiers of Medicine, 2014, 8(1): 6-16. https://doi.org/10.1007/s11684-014-0317-3

    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.

  • REVIEW
    Jingyi Lu, Guoxiang Xie, Weiping Jia, Wei Jia
    Frontiers of Medicine, 2013, 7(1): 53-59. https://doi.org/10.1007/s11684-013-0255-5

    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.

  • REVIEW
    Tianhua Xu, Zitong Sheng, Li Yao
    Frontiers of Medicine, 2017, 11(3): 340-348. https://doi.org/10.1007/s11684-017-0570-3

    In light of the rapid increase in the number of obesity incidences worldwide, obesity has become an independent risk factor for chronic kidney disease. Obesity-related glomerulopathy (ORG) is characterized by glomerulomegaly in the presence or absence of focal and segmental glomerulosclerosis lesions. IgM and complement 3 (C3) nonspecifically deposit in lesions without immune-complex-type deposits during ORG immunofluorescence. ORG-associated glomerulomegaly and focal and segmental glomerulosclerosis can superimpose on other renal pathologies. The mechanisms under ORG are complex, especially hemodynamic changes, inflammation, oxidative stress, apoptosis, and reduced functioning nephrons. These mechanisms synergize with obesity to induce end-stage renal disease. A slow increase of subnephrotic proteinuria (<3.5 g/d) is the most common clinical manifestation of ORG. Several treatment methods for ORG have been developed. Of these methods, renin–angiotensin–aldosterone system blockade and weight loss are proven effective. Targeting mitochondria may offer a novel strategy for ORG therapy. Nevertheless, more research is needed to further understand ORG.

  • REVIEW
    Bo Lei, Baolin Guo, Kunal J. Rambhia, Peter X. Ma
    Frontiers of Medicine, 2019, 13(2): 189-201. https://doi.org/10.1007/s11684-018-0664-6

    Native tissues possess unparalleled physiochemical and biological functions, which can be attributed to their hybrid polymer composition and intrinsic bioactivity. However, there are also various concerns or limitations over the use of natural materials derived from animals or cadavers, including the potential immunogenicity, pathogen transmission, batch to batch consistence and mismatch in properties for various applications. Therefore, there is an increasing interest in developing degradable hybrid polymer biomaterials with controlled properties for highly efficient biomedical applications. There have been efforts to mimic the extracellular protein structure such as nanofibrous and composite scaffolds, to functionalize scaffold surface for improved cellular interaction, to incorporate controlled biomolecule release capacity to impart biological signaling, and to vary physical properties of scaffolds to regulate cellular behavior. In this review, we highlight the design and synthesis of degradable hybrid polymer biomaterials and focus on recent developments in osteoconductive, elastomeric, photoluminescent and electroactive hybrid polymers. The review further exemplifies their applications for bone tissue regeneration.

  • REVIEW
    Chuanfeng Wu, Cynthia E. Dunbar
    Frontiers of Medicine, 2011, 5(4): 356-371. https://doi.org/10.1007/s11684-011-0159-1

    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.

  • REVIEW
    Beicheng Sun, Michael Karin
    Frontiers of Medicine, 2013, 7(2): 242-254. https://doi.org/10.1007/s11684-013-0256-4

    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.

  • REVIEW
    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. https://doi.org/10.1007/s11684-020-0786-5

    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.

  • REVIEW
    Xiaokun Li
    Frontiers of Medicine, 2019, 13(5): 511-530. https://doi.org/10.1007/s11684-019-0711-y

    Members of the fibroblast growth factor (FGF) family play pleiotropic roles in cellular and metabolic homeostasis. During evolution, the ancestor FGF expands into multiple members by acquiring divergent structural elements that enable functional divergence and specification. Heparan sulfate-binding FGFs, which play critical roles in embryonic development and adult tissue remodeling homeostasis, adapt to an autocrine/paracrine mode of action to promote cell proliferation and population growth. By contrast, FGF19, 21, and 23 coevolve through losing binding affinity for extracellular matrix heparan sulfate while acquiring affinity for transmembrane α-Klotho (KL) or β-KL as a coreceptor, thereby adapting to an endocrine mode of action to drive interorgan crosstalk that regulates a broad spectrum of metabolic homeostasis. FGF19 metabolic axis from the ileum to liver negatively controls diurnal bile acid biosynthesis. FGF21 metabolic axes play multifaceted roles in controlling the homeostasis of lipid, glucose, and energy metabolism. FGF23 axes from the bone to kidney and parathyroid regulate metabolic homeostasis of phosphate, calcium, vitamin D, and parathyroid hormone that are important for bone health and systemic mineral balance. The significant divergence in structural elements and multiple functional specifications of FGF19, 21, and 23 in cellular and organismal metabolism instead of cell proliferation and growth sufficiently necessitate a new unified and specific term for these three endocrine FGFs. Thus, the term “FGF Metabolic Axis,” which distinguishes the unique pathways and functions of endocrine FGFs from other autocrine/paracrine mitogenic FGFs, is coined.

  • REVIEW
    Juan Zheng,Shih-Lung Woo,Xiang Hu,Rachel Botchlett,Lulu Chen,Yuqing Huo,Chaodong Wu
    Frontiers of Medicine, 2015, 9(2): 173-186. https://doi.org/10.1007/s11684-015-0384-0

    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.

  • REVIEW
    Chuanqi Liu, Ming Pei, Qingfeng Li, Yuanyuan Zhang
    Frontiers of Medicine, 2022, 16(1): 56-82. https://doi.org/10.1007/s11684-021-0900-3

    Contributing to organ formation and tissue regeneration, extracellular matrix (ECM) constituents provide tissue with three-dimensional (3D) structural integrity and cellular-function regulation. Containing the crucial traits of the cellular microenvironment, ECM substitutes mediate cell–matrix interactions to prompt stem-cell proliferation and differentiation for 3D organoid construction in vitro or tissue regeneration in vivo. However, these ECMs are often applied generically and have yet to be extensively developed for specific cell types in 3D cultures. Cultured cells also produce rich ECM, particularly stromal cells. Cellular ECM improves 3D culture development in vitro and tissue remodeling during wound healing after implantation into the host as well. Gaining better insight into ECM derived from either tissue or cells that regulate 3D tissue reconstruction or organ regeneration helps us to select, produce, and implant the most suitable ECM and thus promote 3D organoid culture and tissue remodeling for in vivo regeneration. Overall, the decellularization methodologies and tissue/cell-derived ECM as scaffolds or cellular-growth supplements used in cell propagation and differentiation for 3D tissue culture in vitro are discussed. Moreover, current preclinical applications by which ECM components modulate the wound-healing process are reviewed.

  • REVIEW
    Min Cheng, Jian Zhang, Wen Jiang, Yongyan Chen, Zhigang Tian
    Frontiers of Medicine, 2012, 6(1): 56-66. https://doi.org/10.1007/s11684-012-0177-7

    Natural killer (NK) cells are considered to be critical players in anticancer immunity. However, cancers are able to develop mechanisms to escape NK cell attack or to induce defective NK cells. Current NK cell-based cancer immunotherapy is aimed at overcoming NK cell paralysis through several potential approaches, including activating autologous NK cells, expanding allogeneic NK cells, usage of stable allogeneic NK cell lines and genetically modifying fresh NK cells or NK cell lines. The stable allogeneic NK cell line approach is more practical for quality-control and large-scale production. Additionally, genetically modifying NK cell lines by increasing their expression of cytokines and engineering chimeric tumor antigen receptors could improve their specificity and cytotoxicity. In this review, NK cells in tumor immunotherapy are discussed, and a list of therapeutic NK cell lines currently undergoing preclinical and clinical trials of several kinds of tumors are reviewed.

  • LETTER TO FRONTIERS OF MEDICINE
    Lingling Tang, Yingan Jiang, Mengfei Zhu, Lijun Chen, Xiaoyang Zhou, Chenliang Zhou, Peng Ye, Xiaobei Chen, Baohong Wang, Zhenyu Xu, Qiang Zhang, Xiaowei Xu, Hainv Gao, Xiaojun Wu, Dong Li, Wanli Jiang, Jingjing Qu, Charlie Xiang, Lanjuan Li
    Frontiers of Medicine, 2020, 14(5): 664-673. https://doi.org/10.1007/s11684-020-0810-9

    The coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 was identified in December 2019. The symptoms include fever, cough, dyspnea, early symptom of sputum, and acute respiratory distress syndrome (ARDS). Mesenchymal stem cell (MSC) therapy is the immediate treatment used for patients with severe cases of COVID-19. Herein, we describe two confirmed cases of COVID-19 in Wuhan to explore the role of MSC in the treatment of COVID-19. MSC transplantation increases the immune indicators (including CD4 and lymphocytes) and decreases the inflammation indicators (interleukin-6 and C-reactive protein). High-flow nasal cannula can be used as an initial support strategy for patients with ARDS. With MSC transplantation, the fraction of inspired O2 (FiO2) of the two patients gradually decreased while the oxygen saturation (SaO2) and partial pressure of oxygen (PO2) improved. Additionally, the patients’ chest computed tomography showed that bilateral lung exudate lesions were adsorbed after MSC infusion. Results indicated that MSC transplantation provides clinical data on the treatment of COVID-19 and may serve as an alternative method for treating COVID-19, particularly in patients with ARDS.

  • REVIEW
    Farhad Sahebjam,John M. Vierling
    Frontiers of Medicine, 2015, 9(2): 187-219. https://doi.org/10.1007/s11684-015-0386-y

    Autoimmune hepatitis is a chronic liver disease putatively caused by loss of tolerance to hepatocyte-specific autoantigens. It is characterized by female predilection, elevated aminotransferase levels, autoantibodies, increased γ-globulin or IgG levels and biopsy evidence of interface hepatitis. It is currently divided into types 1 and 2, based on expression of autoantibodies. Autoantigenic epitopes have been identified only for the less frequent type 2. Although autoimmune hepatitis occurs in childhood, this review focuses on disease in adults. In the absence of pathognomonic biomarkers, diagnosis requires consideration of clinical, biochemical, serological and histological features, which have been codified into validated diagnostic scoring systems. Since many features also occur in other chronic liver diseases, these scoring systems aid evaluation of the differential diagnosis. New practice guidelines have redefined criteria for remission to include complete biochemical and histological normalization on immunosuppressive therapy. Immunosuppression is most often successful using prednisone or prednisolone and azathioprine; however, the combination of budesonide and azathioprine for non-cirrhotic patients offers distinct advantages. Patients failing standard immunosuppression are candidates for alternative immunosuppressive regimens, yet none of the options has been studied in a randomized, controlled trial. Overlap syndromes with either primary sclerosing cholangitis or primary biliary cirrhosis occur in a minority. Liver transplantation represents a life-saving option for patients presenting with acute liver failure, severely decompensated cirrhosis or hepatocellular carcinoma. Transplant recipients are at risk for recurrent autoimmune hepatitis in the allograft, and de novo disease may occur in patients transplanted for other indications. Patients transplanted for AIH are also at risk for recurrent or de novo inflammatory bowel disease. Progress in our understanding of the immunopathogenesis should lead to identification of specific diagnostic and prognostic biomarkers and new therapeutic strategies.

  • REVIEW
    Elena Chung, Guo Chen, Brenton Alexander, Maxime Cannesson
    Frontiers of Medicine, 0: 91-101. https://doi.org/10.1007/s11684-013-0239-5

    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.

  • REVIEW
    Chao Chen, Chang Wang, Chun Hu, Yachun Han, Li Zhao, Xuejing Zhu, Li Xiao, Lin Sun
    Frontiers of Medicine, 2017, 11(3): 310-318. https://doi.org/10.1007/s11684-017-0542-7

    Diabetic kidney disease (DKD) is one of the primary causes of end-stage renal disease (ESRD). Early diagnosis is very important in preventing the development of DKD. Urinary albumin excretion rate (UAER) and glomerular filtration rate (GFR) are widely accepted as criteria for the diagnosis and clinical grading of DKD, and microalbuminuria has been recommended as the first clinical sign of DKD. The natural history of DKD has been divided into three stages: normoalbuminuria, microalbuminuria, and macroalbuminuria. However, this clinical paradigm has been questioned recently, as studies have shown that a portion of diabetes mellitus (DM) patients with normoalbuminuria have progressive renal insufficiency, referred to as normoalbuminuric diabetic kidney disease (NADKD) or nonalbuminuric diabetic nephropathy. Epidemiologic research has demonstrated that normoalbuminuric diabetic kidney disease is common, and the large number of NADKD patients suggests that the traditional paradigm needs to be shifted. Currently, the pathogenesis of NADKD remains unclear, but many clinical studies have identified some clinical and pathological features of NADKD. In addition, the long-term outcomes of NADKD patients remain controversial. In this article, we reviewed the latest studies addressing the pathogenesis, pathology, treatment and prevention of NADKD.

  • REVIEW
    Honglu Zhou, Songmei Wang, Lorenz von Seidlein, Xuanyi Wang
    Frontiers of Medicine, 2020, 14(1): 1-7. https://doi.org/10.1007/s11684-019-0733-5

    With the improvements of sanitation and nationwide safe water supply the occurrence of bacterial diarrhea declined remarkably, while viruses became the leading causes of acute gastroenteritis (AGE). Of these viruses, noroviruses (NoVs) are responsible for a considerable burden of gastroenteritis, especially in children<2 years and elderly≥65 years. NoVs circulating in the Chinese population are antigenically highly diverse with the genotype GII.4 being the dominant strain followed by GII.3. Given the widespread contamination in environmental sources, and highly infectious nature of NoVs, vaccination would be the desirable strategy for the control of NoV infections. However, a better understanding of acquired immunity after infection, and a reliable immunological surrogate marker are urgently needed, since two vaccine candidates based on virus-like particles (VLPs) are currently moving into clinical evaluations in China.