Glucose uptake and distribution across the human skeleton using state-of-the-art total-body PET/CT

A growing number of studies have demonstrated that the skeleton is an endocrine organ that is involved in glucose metabolism and plays a significant role in human glucose homeostasis.However,there is still a limited understanding of the in vivo glucose uptake and distribution across the human skeleton.To address this issue,we aimed to elucidate the detailed profile of glucose uptake across the skeleton using a total-body positron emission tomography(PET)scanner.A total of 41 healthy participants were recruited.Two of them received a 1-hour dynamic total-body^(18)F-fluorodeoxyglucose(^(18)F-FDG)PET scan,and all of them received a10-minute static total-body^(18)F-FDG PET scan.The net influx rate(K_i)and standardized uptake value normalized by lean body mass(SUL)were calculated as indicators of glucose uptake from the dynamic and static PET data,respectively.The results showed that the vertebrae,hip bone and skull had relatively high Kiand SUL values compared with metabolic organs such as the liver.Both the K_(i) and SUL were higher in the epiphyseal,metaphyseal and cortical regions of long bones.Moreover,trends associated with age and overweight with glucose uptake(SUL_(max)and SUL_(mean))in bones were uncovered.Overall,these results indicate that the skeleton is a site with significant glucose uptake,and skeletal glucose uptake can be affected by age and dysregulated metabolism.

Exosomes Derived from Human Umbilical Cord Mesenchymal Stem Cells Enhance Insulin Sensitivity in Insulin Resistant Human Adipocytes

Insulin resistance is an essential characteristic of type 2 diabetes mellitus(T2DM),which can be induced by glucotoxicity and adipose chronic inflammation.Mesenchymal stem cells(MSCs)and their exosomes were reported to ameliorate T2DM and its complications by their immunoregulatory and healing abilities.Exosomes derived from MSCs contain abundant molecules to mediate crosstalk between cells and mimic biological function of MSCs.But the role of exosomes derived from human umbilical cord mesenchymal stem cells(hUC-MSCs)in insulin resistance of human adipocytes is unclear.In this study,exosomes were harvested from the conditioned medium of hUC-MSCs and added to insulin-resistant adipocytes.Insulin-stimulated glucose uptake was measured by glucose oxidase/peroxidase assay.The signal pathway involved in exosome-treated adipocytes was detected by RT-PCR and Western blotting.The biological characteristics and function were compared between hUC-MSCs and human adipose-derived mesenchymal stem cells(hAMSCs).The results showed that hAMSCs had better adipogenic ability than hUC-MSCs.After induction of mature adipocytes by adipogenesis of hAMSC,the model of insulin-resistant adipocytes was successfully established by TNF-αand high glucose intervention.After exosome treatment,the insulin-stimulated glucose uptake was significantly increased.In addition,the effect of exosomes could be stabilized for at least 48 h.Furthermore,the level of leptin was significantly decreased,and the mRNA expression of sirtuin-1 and insulin receptor substrate-1 was significantly upregulated after exosome treatment.In conclusion,exosomes significantly improve insulin sensitivity in insulin-resistant human adipocytes,and the mechanism involves the regulation of adipokines.

Rare myeloid sarcoma/acute myeloid leukemia with adrenal mass after allogeneic mobilization peripheral blood stem cell transplantation

Myeloid sarcoma(MS)is a rare hematological neoplasm that develops either de novo or concurrently with acute myeloid leukemia(AML).This neoplasm can also be an initial manifestation of relapse in a previously treated AML that is in remission.A 44-year-old male patient was diagnosed with testis MS in a local hospital in August 2010.After one month,bone marrow biopsy and aspiration confirmed the diagnosis of AML.Allogeneic mobilization peripheral blood stem cell transplantation was performed,with the sister of the patient as donor,after complete remission(CR)was achieved by chemotherapy.Five months after treatment,an adrenal mass was detected by positron emission tomography-computed tomography(PET-CT).Radiotherapy was performed for the localized mass after a multidisciplinary team(MDT)discussion.The patient is still alive as of May 2013,with no evidence of recurrent MS or leukemia.

IL13Rα1 prevents a castration resistant phenotype of prostate cancer by targeting hexokinase 2 for ubiquitin-mediated degradation

Objective:Androgen deprivation therapy(ADT)is still the principal treatment option for prostate cancer(PCa).In addition to reactivation of androgen receptor signaling,the resistance of PCa to apoptosis during ADT also contributes to castration resistant PCa(CRPC).A previous study reported that gene transfer of IL-13Rα2 into PCa cells sensitized the cells to the IL-13R-targeted cytotoxin IL13Rα1,leading to apoptosis.Compared with IL-13Rα2,IL13Rα1 is more constitutively expressed in PCa cells,but its function in PCa remains to be established.Methods:We determined the role and expression of IL13Rα1 in PCa cancer cells using western blotting,flow cytometry,and cell proliferation assays.Co-immunoprecipitation and mass spectrometry were used to identify the proteins that interacted with IL13Rα1,to elucidate its function.Results:In this study,we showed that IL13Rα1 was selectively suppressed in androgen-deprived PCa cells and that its suppression tended to be associated with poor prognoses of PCa patients.IL13Rα1 overexpression promoted apoptosis and inhibited tumor growth under androgen-deprived or castrated conditions(P<0.01).Mechanistically,IL13Rα1 recruited and facilitated ubiquitin protein ligase E3C-mediated ubiquitination and degradation of hexokinase 2(HK2),resulting in glycolytic inhibition and eventually leading to PCa cell apoptosis.Furthermore,our data revealed that mutated ataxia-telangiectasia kinase phosphorylated and facilitated the selective ubiquitin proteasome-mediated degradation of HK2.Notably,IL13Rα1-overexpressing PCa cells were more susceptible to apoptosis and exhibited reduced tumor growth after exposure to the HK2 inhibitor,2-deoxy-D-glucose(P<0.01).Conclusions:Our data identified a tumor suppressor role for IL13Rα1 in preventing the resistance of PCa cells to apoptosis during androgen deprivation by inhibiting glycolysis.IL13Rα1-mediated signaling involving HK2 may therefore provide a novel treatment target and strategy for CRPC.

^(18)F-FDG PET/MR Imaging for Evaluating of Obstructive Jaundice:Chinese Expert Consensus

The cause of obstructive jaundice is usually complex which renders its differential diagnosis and lesion localization challenging in clinical practice.Integrated Positron Emission tomography/Magnetic Resonance(PET/MR)offers complementary information from PET and MR in the diagnosis of obstructive jaundice and is becoming widely adopted in clinical setting.While preserving its diagnostic accuracy,it is important to standardize and streamline the clinical scan protocol of PET/MR in evaluating obstructive jaundice.Based on literature review and experience of large number of clinical cases from the author group,this article reports an expert consensus on imaging protocol optimization and case interpretation template standardization.