Glycogen metabolism plays a key role in the development of hepatoellular carcinoma(HCC),but the function of glycogen metabolism genes in the tumor microenvironment(TME)is still to be elucidated.Single cell RNA-seq dat...Glycogen metabolism plays a key role in the development of hepatoellular carcinoma(HCC),but the function of glycogen metabolism genes in the tumor microenvironment(TME)is still to be elucidated.Single cell RNA-seq data were obtained from ten HCC tumor samples totaling 64,545 cells and 65 glycogen metabolism genes were analyzed bya nonnegative matrix factorization(NMF).The prognosis and immune response of new glycogen TME cell dusters were predicted by using HCC and immunotherapy cohorts from public databases.HOC single cell analysis was divided into fibroblasts,NT T cells,macrophages,endothelial clls,and B cells,which were separately divided into new cell clusters by glycogen metabolism gene annotation.Pseudo temporal trajectory analysis demonstrated the temporal differentiation trajectory of different glycogen subtype cell dusters.Cellular communication analysis revealed extensive interactions between endothelial cells with glycogen metabolizing TME cell.related subtypes and diferent glycogen subtype cell clusters.SCENIC analysis of transcription factors upstream of TME cell clusters with different glycogen metabolism.In addition,TME cell dusters of glycogen metabolism were found to be enriched in expression in CAF subtypes,CD8 depleted,M1,and M2 types.Bulk seq analysis showed the prognostic signifcance of glycogen metabolism.mediated TME cell dusters in HCC,while a significant immune response was found in the immunotherapy cohort in patients treated with immune checkpoint blockade(ICB),especially for CAFs,T cells,and macrophages In summary,our study reveals for the first time that glycogen metabolism mediates intercellular communication in the hepatocellular carcinoma microenvironment while elucidating the anti-tumor mechanisms and immune prognostic responses of different subtypes of cell dusters.展开更多
Objective: To study the mechanism of hepatocellular glycogen in alleviation of liver ischemia-reperfusion injury during hepatic vascular occlusion for partial hepatectomy. Methods: Seventeen patients were randomly div...Objective: To study the mechanism of hepatocellular glycogen in alleviation of liver ischemia-reperfusion injury during hepatic vascular occlusion for partial hepatectomy. Methods: Seventeen patients were randomly divided into experimental group (n=9) and control group (n=8). In the experimental group, patients were given high concentration glucose intravenously during 24 hours before operation. The hepatic lesion was re- sected after portal triad clamping in the two groups. Non-cancer liver tissue was biopsied to measure he- patic tissue ATP content and change of malondialde- hyde (MDA) and superoxide dismutase (SOD). Liver function of all patients was assessed before operation and the first and fifth day after operation. Results: Hepatic tissue ATP content of the experi- mental group was significantly higher than that of the control group both at the end of hepatic vascular oc- clusion and the point of one-hour reperfusion. Be- sides, liver function of the experimental group was significantly better than that of the control group the first and fifth day after operation. There was signifi- cant difference in SOD activity or MDA content be- tween the two groups at the end of hepatic vascular occlusion and at the point of one-hour reperfusion. Conclusions: Abundant intracellular glycogen may reduce liver ischemia-reperfusion injury caused by hepatic vascular occlusion. It is beneficial to give a large amount of glucose before a complex liver opera- tion, in which temporary occlusion of hepatic blood flow is necessary.展开更多
BACKGROUND: Glycogen storage disease (GSD) is an inherited metabolic disorder in which the concentration and/or structure of glycogen in tissues is abnormal. Essentially, abnormalities in all known enzymes involved in...BACKGROUND: Glycogen storage disease (GSD) is an inherited metabolic disorder in which the concentration and/or structure of glycogen in tissues is abnormal. Essentially, abnormalities in all known enzymes involved in the synthesis or degradation of glycogen and glucose have been found to cause some type of GSD. Liver and muscle have abundant quantities of glycogen and are the most common and seriously affected tissues. This study was to assess reduced-size liver transplantation for the treatment of GSD. METHODS: The clinical data from one case of GSD type I with hepatic adenoma was retrospectively analyzed. The clinical manifestations were hepatomegaly, delayed puberty, growth retardation, sexual immaturity, hypoglycemia, and lactic acidosis, which made the young female patient eligible for reduced-size liver transplantation. RESULTS: The patient recovered uneventfully with satisfactory outcome, including 12 cm growth in height and 5 kg increase in weight during 16 months after successful reduced-size liver transplantation. She has been living a normal life for 4 years so far. CONCLUSIONS: Reduced-size liver transplantation is an effective treatment for GSD with hepatomegaly and hepatic adenoma. Delayed puberty, growth retardation, hypoglycemia and lactic acidosis can be cured by surgery.展开更多
Glycogen storage diseases(GSDs),also referred to as glycogenoses,are inherited metabolic disorders of glycogen metabolism caused by deficiency of enzymes or transporters involved in the synthesis or degradation of gly...Glycogen storage diseases(GSDs),also referred to as glycogenoses,are inherited metabolic disorders of glycogen metabolism caused by deficiency of enzymes or transporters involved in the synthesis or degradation of glycogen leading to aberrant storage and/or utilization.The overall estimated GSD incidence is 1 case per 20000-43000 live births.There are over 20 types of GSD including the subtypes.This heterogeneous group of rare diseases represents inborn errors of carbohydrate metabolism and are classified based on the deficient enzyme and affected tissues.GSDs primarily affect liver or muscle or both as glycogen is particularly abundant in these tissues.However,besides liver and skeletal muscle,depending on the affected enzyme and its expression in various tissues,multiorgan involvement including heart,kidney and/or brain may be seen.Although GSDs share similar clinical features to some extent,there is a wide spectrum of clinical phenotypes.Currently,the goal of treatment is to maintain glucose homeostasis by dietary management and the use of uncooked cornstarch.In addition to nutritional interventions,pharmacological treatment,physical and supportive therapies,enzyme replacement therapy(ERT)and organ transplantation are other treatment approaches for both disease manifestations and longterm complications.The lack of a specific therapy for GSDs has prompted efforts to develop new treatment strategies like gene therapy.Since early diagnosis and aggressive treatment are related to better prognosis,physicians should be aware of these conditions and include GSDs in the differential diagnosis of patients with relevant manifestations including fasting hypoglycemia,hepatomegaly,hypertransaminasemia,hyperlipidemia,exercise intolerance,muscle cramps/pain,rhabdomyolysis,and muscle weakness.Here,we aim to provide a comprehensive review of GSDs.This review provides general characteristics of all types of GSDs with a focus on those with liver involvement.展开更多
Glycogen storage diseases （GSD） are inherited metabolic disorders of glycogen metabolism. Different hormones, including insulin, glucagon, and cortisol regulate the relationship of glycolysis, gluconeogenesis and gl...Glycogen storage diseases （GSD） are inherited metabolic disorders of glycogen metabolism. Different hormones, including insulin, glucagon, and cortisol regulate the relationship of glycolysis, gluconeogenesis and glycogen synthesis. The overall GSD incidence is estimated 1 case per 20000-43000 live births. There are over 12 types and they are classified based on the enzyme deficiency and the affected tissue. Disorders of glycogen degradation may affect primarily the liver, the muscle, or both. Type I a involves the liver, kidney and intestine （and I b also leukocytes）, and the clinical manifestations are hepatomegaly, failure to thrive, hypoglycemia, hyperlactatemia, hyperuricemia and hyperlipidemia. Type Ilia involves both the liver and muscle, and lib solely the liver. The liver symptoms generally improve with age. Type IV usually presents in the first year of life, with hepatomegaly and growth retardation. The disease in general is progressive to cirrhosis. Type Ⅵ and Ⅳ are a heterogeneous group of diseases caused by a deficiency of the liver phosphorylase and phosphorylase kinase system. There is no hyperuricemia or hyperlactatemia. Type Ⅺ is characterized by hepatic glycogenosis and renal Fanconi syndrome. Type Ⅱ is a prototype of inborn lysosomal storage diseases and involves many organs but primarily the muscle. Types V and Ⅶ involve only the muscle.展开更多
Glycogenic hepatopathy(GH) is a rare complication of the poorly controlled diabetes mellitus characterized by the transient liver dysfunction with elevated liver enzymes and associated hepatomegaly caused by the rever...Glycogenic hepatopathy(GH) is a rare complication of the poorly controlled diabetes mellitus characterized by the transient liver dysfunction with elevated liver enzymes and associated hepatomegaly caused by the reversible accumulation of excess glycogen in the hepatocytes. It is predominantly seen in patients with longstanding type 1 diabetes mellitus and rarely reported in association with type 2 diabetes mellitus. Although it was first observed in the pediatric population, since then, it has been reported in adolescents and adults with or without ketoacidosis. The association of GH with hyperglycemia in diabetes has not been well established. One of the essential elements in the pathophysiology of development of GH is the wide fluctuation in both glucose and insulin levels. GH and non-alcoholic fatty liver disease(NAFLD) are clinically indistinguishable, and latter is more prevalent in diabetic patients and can progress to advanced liver disease and cirrhosis. Gradient dual-echo MRI can distinguish GH from NAFLD; however, GH can reliably be diagnosed only by liver biopsy. Adequate glycemic control can result in complete remission of clinical, laboratory and histological abnormalities. There has been a recent report of varying degree of liver fibrosis identified in patients with GH. Future studies are required to understand the biochemical defects underlying GH, noninvasive, rapid diagnostic tests for GH, and to assess the consequence of the fibrosis identified as severe fibrosis may progress to cirrhosis. Awareness of this entity in the medical community including specialists is low. Here we briefly reviewed the English literature on pathogenesis involved, recent progress in the evaluation, differential diagnosis, and management.展开更多
Metabolic liver diseases(MLD)are the second most common indication for liver transplantation(LT)in children.This is based on the fact that the majority of enzymes involved in various metabolic pathways are present wit...Metabolic liver diseases(MLD)are the second most common indication for liver transplantation(LT)in children.This is based on the fact that the majority of enzymes involved in various metabolic pathways are present within the liver and LT can cure or at least control the disease manifestation.LT is also performed in metabolic disorders for end-stage liver disease,its sequelae including hepatocellular cancer.It is also performed for preventing metabolic crisis’,arresting progression of neurological dysfunction with a potential to reverse symptoms in some cases and for preventing damage to end organs like kidneys as in the case of primary hyperoxalosis and methyl malonic acidemia.Pathological findings in explant liver with patients with metabolic disease include unremarkable liver to steatosis,cholestasis,inflammation,variable amount of fibrosis,and cirrhosis.The outcome of LT in metabolic disorders is excellent except for patients with mitochondrial disorders where significant extrahepatic involvement leads to poor outcomes and hence considered a contraindication for LT.A major advantage of LT is that in the post-operative period most patients can discontinue the special formula which they were having prior to the transplant and this increases their well-being and improves growth parameters.Auxiliary partial orthotopic LT has been described for patients with noncirrhotic MLD where a segmental graft is implanted in an orthotopic position after partial resection of the native liver.The retained native liver can be the potential target for future gene therapy when it becomes a clinical reality.展开更多
The fish Prochilodus lineatus (Characiformes, Prochilodontidae), in addition to being a good bioindicator, is also of economic and ecological importance with a broad distribution in the neotropics. Ecotoxicology exami...The fish Prochilodus lineatus (Characiformes, Prochilodontidae), in addition to being a good bioindicator, is also of economic and ecological importance with a broad distribution in the neotropics. Ecotoxicology examines the interaction between environmental chemistry and biota;and in this study we assess alterations of bile and glycogen levels in the fish liver, organ responsible for detoxification, biotransformation and storing nutrients, such as glycogen, and for secreting bile. Fish were separated in three groups to examine the damage caused by the exposure to waters from Lago Azul-Rio Claro-SP and containing diluted biodegradable detergents in comparison to a control group (chlorinated water from an artesian well of UNESP-Campus Rio Claro). A histological analysis was performed on HE and PAS stained sections. The identification of structural changes and the assessment of the area occupied by bile and glycogen were carried out with the software ImageJ, showing that the liver was affected morphologically (cell vacuolization, peripherals nuclei, for example) and problems in bile release and production and storage of glycogen.展开更多
Glycogen plays essential roles in glucose metabolism.Imaging glycogen in the liver,the major glycogen reservoir in the body,may shed new light on many metabolic disorders.^(13)C magnetic resonance spectroscopy(MRS)has...Glycogen plays essential roles in glucose metabolism.Imaging glycogen in the liver,the major glycogen reservoir in the body,may shed new light on many metabolic disorders.^(13)C magnetic resonance spectroscopy(MRS)has become the mainstream method for monitoring glycogen in the body.However,the equipment of special hard-ware to standard clinical magnetic resonance imaging(MRI)scanners limits its clinical applications.Herein,we utilized endogenous glycogen as a T_(2)-based relaxation contrast agent for imaging glycogen metabolism in the liver in vivo.The in vitro results demonstrated that the transverse relaxation rate of glycogen strongly correlates with the concentration,pH,and field strength.Based on the Swift-Connick theory,we characterized the exchange property of glycogen and measured the exchange rate of glycogen as 31,847 Hz at 37°C.Besides,the viscosity and echo spacing showed no apparent effect on the transverse relaxation rate.This unique feature enables vi-sualization of glycogen signaling in vivo through T_(2)-weighted MRI.Two hours-post intraperitoneal injection of glucagon,a clinical drug to promote glycogenolysis and gluconeogenesis,the signal intensity of the mice’s liver increased by 1.8 times from the T_(2)-weighted imaging experiment due to the decomposition of glycogen.This study provides a convenient imaging strategy to non-invasively investigate glycogen metabolism in the liver,which may find clinical applications in metabolic diseases.展开更多
基金Liuzhou City's Top Ten Hundred Talents Project,Liuzhou Science and Technology Project(Grant Nos.2021CBC0126 and 2021CBC0123)Guangxi Zhuang Autonomous Region Health and Family Planning Commission Projects(Z20210561,Z20210903)+1 种基金liuzhou Scienceand Technology Plan Projects(2021CBC0121,2021CBC0128).
文摘Glycogen metabolism plays a key role in the development of hepatoellular carcinoma(HCC),but the function of glycogen metabolism genes in the tumor microenvironment(TME)is still to be elucidated.Single cell RNA-seq data were obtained from ten HCC tumor samples totaling 64,545 cells and 65 glycogen metabolism genes were analyzed bya nonnegative matrix factorization(NMF).The prognosis and immune response of new glycogen TME cell dusters were predicted by using HCC and immunotherapy cohorts from public databases.HOC single cell analysis was divided into fibroblasts,NT T cells,macrophages,endothelial clls,and B cells,which were separately divided into new cell clusters by glycogen metabolism gene annotation.Pseudo temporal trajectory analysis demonstrated the temporal differentiation trajectory of different glycogen subtype cell dusters.Cellular communication analysis revealed extensive interactions between endothelial cells with glycogen metabolizing TME cell.related subtypes and diferent glycogen subtype cell clusters.SCENIC analysis of transcription factors upstream of TME cell clusters with different glycogen metabolism.In addition,TME cell dusters of glycogen metabolism were found to be enriched in expression in CAF subtypes,CD8 depleted,M1,and M2 types.Bulk seq analysis showed the prognostic signifcance of glycogen metabolism.mediated TME cell dusters in HCC,while a significant immune response was found in the immunotherapy cohort in patients treated with immune checkpoint blockade(ICB),especially for CAFs,T cells,and macrophages In summary,our study reveals for the first time that glycogen metabolism mediates intercellular communication in the hepatocellular carcinoma microenvironment while elucidating the anti-tumor mechanisms and immune prognostic responses of different subtypes of cell dusters.
文摘Objective: To study the mechanism of hepatocellular glycogen in alleviation of liver ischemia-reperfusion injury during hepatic vascular occlusion for partial hepatectomy. Methods: Seventeen patients were randomly divided into experimental group (n=9) and control group (n=8). In the experimental group, patients were given high concentration glucose intravenously during 24 hours before operation. The hepatic lesion was re- sected after portal triad clamping in the two groups. Non-cancer liver tissue was biopsied to measure he- patic tissue ATP content and change of malondialde- hyde (MDA) and superoxide dismutase (SOD). Liver function of all patients was assessed before operation and the first and fifth day after operation. Results: Hepatic tissue ATP content of the experi- mental group was significantly higher than that of the control group both at the end of hepatic vascular oc- clusion and the point of one-hour reperfusion. Be- sides, liver function of the experimental group was significantly better than that of the control group the first and fifth day after operation. There was signifi- cant difference in SOD activity or MDA content be- tween the two groups at the end of hepatic vascular occlusion and at the point of one-hour reperfusion. Conclusions: Abundant intracellular glycogen may reduce liver ischemia-reperfusion injury caused by hepatic vascular occlusion. It is beneficial to give a large amount of glucose before a complex liver opera- tion, in which temporary occlusion of hepatic blood flow is necessary.
文摘BACKGROUND: Glycogen storage disease (GSD) is an inherited metabolic disorder in which the concentration and/or structure of glycogen in tissues is abnormal. Essentially, abnormalities in all known enzymes involved in the synthesis or degradation of glycogen and glucose have been found to cause some type of GSD. Liver and muscle have abundant quantities of glycogen and are the most common and seriously affected tissues. This study was to assess reduced-size liver transplantation for the treatment of GSD. METHODS: The clinical data from one case of GSD type I with hepatic adenoma was retrospectively analyzed. The clinical manifestations were hepatomegaly, delayed puberty, growth retardation, sexual immaturity, hypoglycemia, and lactic acidosis, which made the young female patient eligible for reduced-size liver transplantation. RESULTS: The patient recovered uneventfully with satisfactory outcome, including 12 cm growth in height and 5 kg increase in weight during 16 months after successful reduced-size liver transplantation. She has been living a normal life for 4 years so far. CONCLUSIONS: Reduced-size liver transplantation is an effective treatment for GSD with hepatomegaly and hepatic adenoma. Delayed puberty, growth retardation, hypoglycemia and lactic acidosis can be cured by surgery.
文摘Glycogen storage diseases(GSDs),also referred to as glycogenoses,are inherited metabolic disorders of glycogen metabolism caused by deficiency of enzymes or transporters involved in the synthesis or degradation of glycogen leading to aberrant storage and/or utilization.The overall estimated GSD incidence is 1 case per 20000-43000 live births.There are over 20 types of GSD including the subtypes.This heterogeneous group of rare diseases represents inborn errors of carbohydrate metabolism and are classified based on the deficient enzyme and affected tissues.GSDs primarily affect liver or muscle or both as glycogen is particularly abundant in these tissues.However,besides liver and skeletal muscle,depending on the affected enzyme and its expression in various tissues,multiorgan involvement including heart,kidney and/or brain may be seen.Although GSDs share similar clinical features to some extent,there is a wide spectrum of clinical phenotypes.Currently,the goal of treatment is to maintain glucose homeostasis by dietary management and the use of uncooked cornstarch.In addition to nutritional interventions,pharmacological treatment,physical and supportive therapies,enzyme replacement therapy(ERT)and organ transplantation are other treatment approaches for both disease manifestations and longterm complications.The lack of a specific therapy for GSDs has prompted efforts to develop new treatment strategies like gene therapy.Since early diagnosis and aggressive treatment are related to better prognosis,physicians should be aware of these conditions and include GSDs in the differential diagnosis of patients with relevant manifestations including fasting hypoglycemia,hepatomegaly,hypertransaminasemia,hyperlipidemia,exercise intolerance,muscle cramps/pain,rhabdomyolysis,and muscle weakness.Here,we aim to provide a comprehensive review of GSDs.This review provides general characteristics of all types of GSDs with a focus on those with liver involvement.
文摘Glycogen storage diseases （GSD） are inherited metabolic disorders of glycogen metabolism. Different hormones, including insulin, glucagon, and cortisol regulate the relationship of glycolysis, gluconeogenesis and glycogen synthesis. The overall GSD incidence is estimated 1 case per 20000-43000 live births. There are over 12 types and they are classified based on the enzyme deficiency and the affected tissue. Disorders of glycogen degradation may affect primarily the liver, the muscle, or both. Type I a involves the liver, kidney and intestine （and I b also leukocytes）, and the clinical manifestations are hepatomegaly, failure to thrive, hypoglycemia, hyperlactatemia, hyperuricemia and hyperlipidemia. Type Ilia involves both the liver and muscle, and lib solely the liver. The liver symptoms generally improve with age. Type IV usually presents in the first year of life, with hepatomegaly and growth retardation. The disease in general is progressive to cirrhosis. Type Ⅵ and Ⅳ are a heterogeneous group of diseases caused by a deficiency of the liver phosphorylase and phosphorylase kinase system. There is no hyperuricemia or hyperlactatemia. Type Ⅺ is characterized by hepatic glycogenosis and renal Fanconi syndrome. Type Ⅱ is a prototype of inborn lysosomal storage diseases and involves many organs but primarily the muscle. Types V and Ⅶ involve only the muscle.
文摘Glycogenic hepatopathy(GH) is a rare complication of the poorly controlled diabetes mellitus characterized by the transient liver dysfunction with elevated liver enzymes and associated hepatomegaly caused by the reversible accumulation of excess glycogen in the hepatocytes. It is predominantly seen in patients with longstanding type 1 diabetes mellitus and rarely reported in association with type 2 diabetes mellitus. Although it was first observed in the pediatric population, since then, it has been reported in adolescents and adults with or without ketoacidosis. The association of GH with hyperglycemia in diabetes has not been well established. One of the essential elements in the pathophysiology of development of GH is the wide fluctuation in both glucose and insulin levels. GH and non-alcoholic fatty liver disease(NAFLD) are clinically indistinguishable, and latter is more prevalent in diabetic patients and can progress to advanced liver disease and cirrhosis. Gradient dual-echo MRI can distinguish GH from NAFLD; however, GH can reliably be diagnosed only by liver biopsy. Adequate glycemic control can result in complete remission of clinical, laboratory and histological abnormalities. There has been a recent report of varying degree of liver fibrosis identified in patients with GH. Future studies are required to understand the biochemical defects underlying GH, noninvasive, rapid diagnostic tests for GH, and to assess the consequence of the fibrosis identified as severe fibrosis may progress to cirrhosis. Awareness of this entity in the medical community including specialists is low. Here we briefly reviewed the English literature on pathogenesis involved, recent progress in the evaluation, differential diagnosis, and management.
文摘Metabolic liver diseases(MLD)are the second most common indication for liver transplantation(LT)in children.This is based on the fact that the majority of enzymes involved in various metabolic pathways are present within the liver and LT can cure or at least control the disease manifestation.LT is also performed in metabolic disorders for end-stage liver disease,its sequelae including hepatocellular cancer.It is also performed for preventing metabolic crisis’,arresting progression of neurological dysfunction with a potential to reverse symptoms in some cases and for preventing damage to end organs like kidneys as in the case of primary hyperoxalosis and methyl malonic acidemia.Pathological findings in explant liver with patients with metabolic disease include unremarkable liver to steatosis,cholestasis,inflammation,variable amount of fibrosis,and cirrhosis.The outcome of LT in metabolic disorders is excellent except for patients with mitochondrial disorders where significant extrahepatic involvement leads to poor outcomes and hence considered a contraindication for LT.A major advantage of LT is that in the post-operative period most patients can discontinue the special formula which they were having prior to the transplant and this increases their well-being and improves growth parameters.Auxiliary partial orthotopic LT has been described for patients with noncirrhotic MLD where a segmental graft is implanted in an orthotopic position after partial resection of the native liver.The retained native liver can be the potential target for future gene therapy when it becomes a clinical reality.
文摘The fish Prochilodus lineatus (Characiformes, Prochilodontidae), in addition to being a good bioindicator, is also of economic and ecological importance with a broad distribution in the neotropics. Ecotoxicology examines the interaction between environmental chemistry and biota;and in this study we assess alterations of bile and glycogen levels in the fish liver, organ responsible for detoxification, biotransformation and storing nutrients, such as glycogen, and for secreting bile. Fish were separated in three groups to examine the damage caused by the exposure to waters from Lago Azul-Rio Claro-SP and containing diluted biodegradable detergents in comparison to a control group (chlorinated water from an artesian well of UNESP-Campus Rio Claro). A histological analysis was performed on HE and PAS stained sections. The identification of structural changes and the assessment of the area occupied by bile and glycogen were carried out with the software ImageJ, showing that the liver was affected morphologically (cell vacuolization, peripherals nuclei, for example) and problems in bile release and production and storage of glycogen.
基金This work is supported by the National Key R&D Program of China(2018YFA0704000)the National Natural Science Foundation of China(91859206,U21A20392,82127802 and 21921004)+2 种基金the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(ZDBS-LY-JSC004)the Scientific Instrument Developing Project of the Chi-nese Academy of Sciences(GJJSTD20200002)Xin Zhou acknowledges the support from the Tencent Foundation through the XPLORER PRIZE.
文摘Glycogen plays essential roles in glucose metabolism.Imaging glycogen in the liver,the major glycogen reservoir in the body,may shed new light on many metabolic disorders.^(13)C magnetic resonance spectroscopy(MRS)has become the mainstream method for monitoring glycogen in the body.However,the equipment of special hard-ware to standard clinical magnetic resonance imaging(MRI)scanners limits its clinical applications.Herein,we utilized endogenous glycogen as a T_(2)-based relaxation contrast agent for imaging glycogen metabolism in the liver in vivo.The in vitro results demonstrated that the transverse relaxation rate of glycogen strongly correlates with the concentration,pH,and field strength.Based on the Swift-Connick theory,we characterized the exchange property of glycogen and measured the exchange rate of glycogen as 31,847 Hz at 37°C.Besides,the viscosity and echo spacing showed no apparent effect on the transverse relaxation rate.This unique feature enables vi-sualization of glycogen signaling in vivo through T_(2)-weighted MRI.Two hours-post intraperitoneal injection of glucagon,a clinical drug to promote glycogenolysis and gluconeogenesis,the signal intensity of the mice’s liver increased by 1.8 times from the T_(2)-weighted imaging experiment due to the decomposition of glycogen.This study provides a convenient imaging strategy to non-invasively investigate glycogen metabolism in the liver,which may find clinical applications in metabolic diseases.
