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Encouraged by our recent findings that 4′-cyano-deoxyguanosine (2), entecavir analogues 4 and 5 are highly potent anti-hepatitis B virus (HBV) agents, we designed and synthesized 6 having a hybridized structure of 4 and 5.

AIMS We aimed to assess the optimal management of first or later-line lenvatinib therapy (LEN) for patients with unresectable hepatocellular carcinoma (uHCC), by clarifying the difference of degree between relative dose intensity (RDI) to achieve objective response (OR) and disease control (DC) by aiming at stable disease (SD), taking dose modifications into consideration. METHODS One hundred uHCC patients who received LEN in first- or later-line settings, between April 2018 and December 2020 in our hospital were analyzed retrospectively. The factors associated with overall survival (OS), time to progression (TTP), OR and DC were assessed. The optimal cut-off values of RDI 4 weeks after initiation of LEN (RDI during cycle 1) and total RDI (RDI during all cycles) to predict achievement of OR and DC by aiming at SD were determined by receiver operator curve analysis. RESULTS Achievement of OR and SD were favorable factors for OS (HR, 0.080 and 0.20) and TTP (HR, 0.052 and 0.073), with progressive disease defined as the reference. RDI ≥ 0.8 during cycle 1 and RDI ≥ 0.4 during cycle 1 contributed to achievement of OR (odds ratio, 3.28) and DC (odds ratio, 4.85), respectively. Experience of dose interruption was associated with a favorable TTP (HR, 0.58). The therapeutic line of LEN did not contribute to OS, TTP or best response. CONCLUSIONS To achieve OR and SD for a favorable outcome of first- or later-line LEN, high and moderate early-phase RDI are required, respectively. The degree of RDI during LEN and tolerance need compatible by dose modifications.

Evaluation of intrahepatic covalently closed circular DNA (cccDNA) is a key for searching an elimination of hepatitis B virus (HBV) infection. HBV RNA and HBV core-related antigen have been proposed as surrogate markers for evaluating cccDNA activity, although they do not necessarily estimate the amount of cccDNA. Here, we developed a novel multiscale mathematical model describing intra- and inter-cellular viral propagation, based on the experimental quantification data in both HBV-infected cell culture and humanized mouse models. We applied it to HBV-infected patients under treatment and developed a model which can predict intracellular HBV dynamics only by use of noninvasive extracellular surrogate biomarkers. Importantly, the model prediction of the amount of cccDNA in patients over time was confirmed to be well-correlated with the liver biopsy data. Thus, our noninvasive method enables to predict the amount of cccDNA in patients and contributes to determining the treatment endpoint required for elimination of intrahepatic cccDNA.

Background & Aims While certain nucleos(t)ide reverse transcriptase inhibitors (NRTIs) are efficacious in treating HBV infection, their effects are yet to be optimized and the emergence of NRTI-resistant HBV variants is an issue because of the requirement for lifelong treatment. The development of agents that more profoundly suppress wild-type and drug-resistant HBVs, and that have a long-acting effect, are crucial to improve patient outcomes. Methods Herein, we synthesized a novel long-acting 4’-modified NRTI termed E-CFCP. We tested its anti-HBV activity in vitro, before evaluating its anti-HBV activity in HBV-infected human-liver-chimeric mice (PXB-mice). E-CFCP’s long-acting features and E-CFCP-triphosphate’s interactions with the HBV reverse transcriptase (HBV-RT) were examined. Results E-CFCP potently blocked HBVWTD1 production (IC50qPCR_cell=1.8 nM) in HepG2.2.15 cells and HBVWTC2 (IC50SB_cell=0.7 nM), entecavir (ETV)-resistant HBVETV-RL180M/S202G/M204V (IC50SB_cell=77.5 nM), and adefovir-resistant HBVADV-RA181T/N236T production (IC50SB_cell=14.1 nM) in Huh7 cells. E-CFCP profoundly inhibited intracellular HBV DNA production to below the detection limit, but ETV and tenofovir alafenamide (TAF) failed to do so. E-CFCP also showed less toxicity than ETV and TAF. E-CFCP better penetrated hepatocytes and was better tri-phosphorylated; E-CFCP-triphosphate persisted intracellularly for longer than ETV-triphosphate. Once-daily peroral E-CFCP administration over 2 weeks (0.02~0.2 mg/kg/day) reduced HBVWTC2-viremia by 2–3 logs in PXB-mice without significant toxicities and the reduction persisted over 1–3 weeks following treatment cessation, suggesting once-weekly dosing capabilities. E-CFCP also reduced HBVETV-RL180M/S202G/M204V-viremia by 2 logs over 2 weeks, while ETV completely failed to reduce HBVETV-RL180M/S202G/M204V-viremia. E-CFCP’s 4’-cyano and fluorine interact with both HBVWT-RT and HBVETV-RL180M/S202G-M204 -RT via Van der Waals and polar forces, being important for E-CFCP-triphosphate’s interactions and anti-HBV potency. Conclusion E-CFCP represents the first reported potential long-acting NRTI with potent activity against wild-type and treatment-resistant HBV. Lay summary Although there are currently effective treatment options for HBV, treatment-resistant variants and the need for lifelong therapy pose a significant challenge. Therefore, the development of new treatment options is crucial to improve outcomes and quality of life. Herein, we report preclinical evidence showing that the anti-HBV agent, E-CFCP, has potent activity against wild-type and treatment-resistant variants. In addition, once-weekly oral dosing may be possible, which is preferrable to the current daily dosing regimens.

Hepatitis B virus (HBV) causes acute and, most importantly, chronic hepatitis B worldwide. Antiviral treatments have been developed to reduce viral loads but few patients with chronic hepatitis B (CHB) achieve a functional cure. The development of new therapeutic agents is desirable. Recently, many novel agents have been developed, including drugs targeting HBV-DNA and HBV-RNA. This review provides an overview of the developmental status of these drugs, especially direct acting antiviral agents (DAAs). Serological biomarkers of HBV infection are essential for predicting the clinical course of CHB. It is also important to determine the amount and activity of covalently closed circular DNA (cccDNA) in the nuclei of infected hepatocytes. Hepatitis B core-associated antigen (HBcrAg) is a new HBV marker that has an important role in reflecting cccDNA in CHB, because it is associated with hepatic cccDNA, as well as serum HBV DNA. The highly sensitive HBcrAg (iTACT-HBcrAg) assay could be a very sensitive HBV activation marker and an alternative to HBV DNA testing for monitoring reactivation. Many of the drugs currently in clinical trials have shown efficacy in reducing hepatitis B surface antigen (HBsAg) levels. Combination therapies with DAAs and boost immune response are also under development; finding the best combinations will be important for therapeutic development.

Hepatitis B virus (HBV) infection is a major risk factor for hepatocellular carcinoma (HCC) development and is a global public health issue. High performance biomarkers can aid the early detection of HCC development in HBV-infected individuals. In addition, advances in the understanding of the pathogenesis of HBV infection and in clinical laboratory techniques have enabled the establishment of disease-specific tests, prediction of the progression of liver diseases, including HCC, and auxiliary diagnosis of HCC, using blood-based methods instead of biopsies of liver or HCC tissues. Viral factors such as the HBV genotype, HBV genetic mutations, HBV DNA, and HBV-related antigens, as well as host factors, such as tumor-associated proteins and post-translational modifications, especially glycosylated proteins, can be blood-based, disease-specific biomarkers for HCC development in HBV-infected patients. In this review, we describe the clinical applications of viral biomarkers, including the HBV genome and glycosylated proteins, for patients at a risk of HBV-related HCC, based on their molecular mechanisms. In addition, we introduce promising biomarker candidates for practical use, including colony stimulating factor 1 receptor (CSF1R), extracellular vesicles, and cell-free, circulating tumor DNA. The clinical use of such surrogate markers may lead to a better understanding of the risk of disease progression and early detection of HCC in HBV-infected patients, thereby improving their prognosis.

The persistence of covalently closed circular DNA (cccDNA) poses a major obstacle to curing chronic hepatitis B (CHB). Here, we used droplet digital PCR (ddPCR) for cccDNA quantitation. ddPCR measured a less than two-fold difference in the intrahepatic cccDNA content more accurately than conventional real-time PCR (qPCR), (R2=0.9416 and R2=0.8963, respectively) and had also higher sensitivity and specificity than qPCR. The results of ddPCR correlated more closely with serum HB core-related antigen (R2=0.9843) than HB surface antigen (HBsAg) (R2=0.9742) in 24 HBV-infected human-liver-chimeric mice (PXB-mice). We demonstrated that the total cccDNA content did not change during liver repopulation, although the cccDNA content per hepatocyte was reduced in PXB-mice after entecavir treatment. In the 6 patients with HBV-related hepatocellular carcinoma, ddPCR detected cccDNA in both tumor and non-tumor tissues. In 13 HBeAg-negative CHB patients with pegylated interferon alpha-2a, cccDNA contents from paired biopsies were more significantly reduced in virological response (VR) than in non-VR at week 48 (p=0.0051). Interestingly, cccDNA levels were the lowest in VR with HBsAg clearance but remained detectable after the treatment. Collectively, ddPCR revealed that cccDNA content is stable during hepatocyte proliferation and persists at quantifiable levels, even after serum HBsAg clearance.

Hepatitis B virus (HBV) genotype F1b infection is strongly associated with hepatocellular carcinoma (HCC) in young Alaskan Native (AN) people. However, the mechanisms by which genotype F1b causes HCC are unclear. Here, we analyzed the clinical and virological significance of genotype F1b in long-term serial samples from 20 HCC patients with HBV infection. Complete sequence analyses revealed that all isolates were genotype F1b. In the HCC patients, T1938C and A2051C mutations in the core region had accumulated significantly with A1762T/G1764A mutations in the basal core promoter (BCP) region and G1896A mutation in the precore (PC) region. Several HBV clones containing the core mutations were examined for their replication efficiency and core stability in vitro. Clones containing the A2051C mutation replicated more efficiently than the wild type in association with enhanced stability of core protein dimerization. In chimeric mice with human hepatocytes carrying BCP/PC/2051 mutant but not with wild-type virus, liver fibrosis was induced in association with high levels of serum HBV DNA and hepatitis B surface antigen. Interestingly, microarray analysis and validation study showed that five genes associated with cell proliferation or carcinogenesis, v-myc avian myelocytomatosis viral oncogene homolog, Grb2-associated binding protein 2, bradykinin receptor B2, follistatin, and mitogen-activated protein kinase kinase kinase 8, were significantly up-regulated in human hepatocytes infected with genotype F1b, particularly the BCP/PC/2051 mutant, compared with other genotypes. Conclusion: We have identified an association between Alaska-specific core mutations and HCC development in AN people infected with genotype F1b; accumulation of these core mutations during the course of chronic infection with genotype F1b would contribute to HCC development in AN people earlier in life.

Diabetic nephropathy (DN) is the major cause of end-stage renal failure and is associated with increased morbidity and mortality as compared to other causes of renal disease. Albuminuria is often the first clinical indicator of the presence of DN. However, albuminuria or proteinuria is a common symptom in patients with various renal disorders. Therefore, specific biomarkers for the diagnosis of DN are required. A primary hallmark of DN is the progressive damage and death of glomerular podocytes, resulting in the leaking of proteins into the urine. Urinary exosomes released by podocytes are microvesicles containing information of the originated cells. Podocyte-derived signal transduction factors (PDSTFs) are good candidates to assess podocyte injuries. The profile of PDSTFs in urinary exosomes from patients with DN is different from that from patients with minimal change nehrotic syndrome. In addition, PDSTFs molecules in exosomes were derived from primary murine podocytes under high glucose conditions. Among PDSTFs in urinary exosomes, Wilms tumor 1 (WT1) levels reflected damage of diabetic glomeruli in the patients. Urinary exosomal WT1 can predict the decline in eGFR for the following several years. In conclusion, urinary exosomal WT1 is a useful biomarker to improve risk stratification in patients with DN. J. Med. Invest. 65:208-215, August, 2018.

We designed, synthesized, and characterized a novel nucleoside analog, (1S,3S,5S)-3-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-5-hydroxy-1-(hydroxymethyl)-2-methylene-cyclopentanecarbonitrile, or 4′-cyano-methylenecarbocyclic-2′-deoxyguanosine (CMCdG), and evaluated its anti-hepatitis B virus (anti-HBV) activity, safety, and related features. CMCdG’s in vitro activity was determined using quantitative PCR and Southern blotting assays, and its cytotoxicity was determined with a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, while its in vivo activity and safety were determined in human liver-chimeric mice infected with wild-type HBV genotype Ce (HBV(WT)(Ce)) and an entecavir (ETV)-resistant HBV variant containing the amino acid substitutions L180M, S202G, and M204V (HBV(ETV-R)(L180M/S202G/M204V)). CMCdG potently inhibited HBV production in HepG2.2.15 cells (50% inhibitory concentration [IC(50)], ∼30 nM) and HBV(WT)(Ce) plasmid-transfected Huh7 cells (IC(50), 206 nM) and efficiently suppressed ETV-resistant HBV(ETV-R)(L180M/S202G/M204V) (IC(50), 2,657 nM), while it showed no or little cytotoxicity (50% cytotoxic concentration, >500 μM in most hepatocytic cells examined). Two-week peroral administration of CMCdG (1 mg/kg of body weight/day once a day [q.d.]) to HBV(WT)(Ce)-infected human liver-chimeric mice reduced the level of viremia by ∼2 logs. CMCdG also reduced the level of HBV(ETV-R)(L180M/S202G/M204V) viremia by ∼1 log in HBV(ETV-R)(L180M/S202G/M204V)-infected human liver-chimeric mice, while ETV (1 mg/kg/day q.d.) completely failed to reduce the viremia. None of the CMCdG-treated mice had significant drug-related changes in body weights or serum human albumin levels. Structural analyses using homology modeling, semiempirical quantum methods, and molecular dynamics revealed that although ETV triphosphate (TP) forms good van der Waals contacts with L180 and M204 of HBV(WT)(Ce) reverse transcriptase (RT), its contacts with the M180 substitution are totally lost in the HBV(ETV-R)(L180M/S202G/M204V) RT complex. However, CMCdG-TP retains good contacts with both the HBV(WT)(Ce) RT and HBV(ETV-R)(L180M/S202G/M204V) RT complexes. The present data warrant further studies toward the development of CMCdG as a potential therapeutic for patients infected with drug-resistant HBV and shed light on the further development of more potent and safer anti-HBV agents.

We designed, synthesized and identified a novel nucleoside derivative, 4’-C-cyano-7-deaza-7-fluoro-2’-deoxyadenosine (CdFA), which exerts potent anti-HBV activity (IC(50) ~26 nM) with favorable hepatocytotoxicity (CC(50)~56 μM). Southern blot analysis using wild-type HBV (HBV(WT))-encoding-plasmid-transfected HepG2 cells revealed that CdFA efficiently suppresses the production of HBV(WT) (IC(50)=153.7 nM), entecavir (ETV)-resistant HBV carrying L180M/S202G/M204V substitutions (HBV(ETV)(R); IC(50)=373.2 nM), and adefovir dipivoxil (ADV)-resistant HBV carrying A181T/N236T substitutions (HBV(ADV)(R); IC(50=)192.6 nM), whereas ETV and ADV were less potent against HBV(ETV)(R) and HBV(ADV)(R) (IC(50): >1,000 and 4,022.5 nM, respectively). Once-daily peroral administration of CdFA to human-liver-chimeric mice over 14 days (1 mg/kg/day) comparably blocked HBV(WT) and HBV(ETV)(R) viremia by 0.7 and 1.2 logs, respectively, without significant changes in body-weight or serum human-albumin levels, although ETV only slightly suppressed HBV(ETV)(R) viremia (CdFA vs ETV; p=0.032). Molecular modeling suggested that ETV-TP has good nonpolar interactions with HBV(WT) reverse transcriptase (RT(WT))’s Met204 and Asp205, while CdFA-TP fails to interact with Met204, in line with the relatively inferior activity against HBV(WT) of CdFA compared to ETV (IC(50): 0.026 versus 0.003 nM). In contrast, the 4’-cyano of CdFA-TP forms good nonpolar contacts with RT(WT)’s Leu180 and RT(ETV)(R)’s Met180, while ETV-TP loses interactions with RT(ETV)(R)’s Met180, explaining in part why ETV is less potent against HBV(ETV)(R) than CdFA. The present results show that CdFA exerts potent activity against HBV(WT), HBV(ETV)(R) and HBV(ADV)(R) with enhanced safety and that 7-deaza-7-fluoro modification confers potent activity against drug-resistant HBV variants and favorable safety, shedding light to further design more potent and safer anti-HBV nucleoside analogs.

Certain nucleoside/nucleotide reverse transcriptase (RT) inhibitors (NRTIs) are effective against human immunodeficiency virus type 1 (HIV-1) and hepatitis B virus (HBV). However, both viruses often acquire NRTI resistance, making it crucial to develop more-potent agents that offer profound viral suppression. Here, we report that 4′-C-cyano-2-amino-2′-deoxyadenosine (CAdA) is a novel, highly potent inhibitor of both HBV (half maximal inhibitory concentration [IC50] = 0.4 nM) and HIV-1 (IC50 = 0.4 nM). In contrast, the approved anti-HBV NRTI, entecavir (ETV), potently inhibits HBV (IC50 = 0.7 nM), but is much less active against HIV-1 (IC50 = 1,000 nM). Similarly, the highly potent HIV-1 inhibitor, 4′-ethynyl-2-fluoro-2′-deoxyadenosine (EFdA; IC50 = 0.3 nM) is less active against HBV (IC50 = 160 nM). Southern analysis using Huh-7 cells transfected with HBV-containing plasmids demonstrated that CAdA was potent against both wild-type (IC50 = 7.2 nM) and ETV-resistant HBV (IC50 = 69.6 nM for HBVETV‐RL180M/S202G/M204V), whereas ETV failed to reduce HBVETV‐RL180M/S202G/M204V DNA even at 1 μM. Once-daily peroral administration of CAdA reduced HBVETV‐RL180M/S202G/M204V viremia (P = 0.0005) in human-liver-chimeric/ HBVETV‐RL180M/S202G/M204V–infected mice, whereas ETV completely failed to reduce HBVETV‐RL180M/S202G/M204V viremia. None of the mice had significant drug-related body-weight or serum human-albumin concentration changes. Molecular modeling suggests that a shallower HBV-RT hydrophobic pocket at the polymerase active site can better accommodate the slightly shorter 4′-cyano of CAdA-triphosphate (TP), but not the longer 4′-ethynyl of EFdA-TP. In contrast, the deeper HIV-1-RT pocket can efficiently accommodate the 4′-substitutions of both NRTIs. The ETV-TP's cyclopentyl ring can bind more efficiently at the shallow HBV-RT binding pocket. Conclusion: These data provide insights on the structural and functional associations of HBV- and HIV-1-RTs and show that CAdA may offer new therapeutic options for HBV patients. (Hepatology 2015;62:1024-1036)

A 23-year-old nulliparous woman, a hepatitis B virus (HBV) carrier with stable liver functions, presented with exacerbation of viral replication (HBV DNA level >9.0 log copies/mL) in gestational week 26. During the subsequent follow up without antiviral therapy, she was hospitalized with progression to hepatic failure in gestational week 35. Following initiation of antiviral therapy with lamivudine, emergent cesarean delivery was conducted for fetal safety. Liver atrophy and persistent hepatic encephalopathy (stage 2) necessitated artificial liver support (ALS) involving online hemodiafiltration (HDF) and plasma exchange. She regained full consciousness after the sixth online HDF session. ALS was terminated after the seventh online HDF session. On day 33 of hospitalization, she was discharged home without sequelae. Genetic analysis of the HBV strain isolated from her serum showed that this strain had genotype C. Direct full-length sequencing identified no known mutations associated with fulminant hepatitis B. HBV-related hepatic failure observed in the present case might have been related to perinatal changes in the host immune response.

The aim of this study was to investigate the effect of dietary lemon polyphenols on high-fat diet-induced obesity in mice, and on the regulation of the expression of the genes involved in lipid metabolism to elucidate the mechanisms. Mice were divided into three groups and fed either a low fat diet (LF) or a high fat diet (HF) or a high fat diet supplemented with 0.5% w/w lemon polyphenols (LP) extracted from lemon peel for 12 weeks. Body weight gain, fat pad accumulation, the development of hyperlipidemia, hyperglycemia, and insulin resistance were significantly suppressed by lemon polyphenols. Supplementation with lemon polyphenols also significantly up-regulated the mRNA level of the peroxisome proliferator activated receptor-alpha (PPARalpha) compared to the LF and HF groups in the liver. Furthermore, the mRNA level of acyl-CoA oxidase (ACO) was up-regulated in the LP group compared to the LF group, but not HF group in the liver, and was also significantly increased in the epididymal white adipose tissue. Thus, feeding with lemon polyphenols suppressed body weight gain and body fat accumulation by increasing peroxisomal beta-oxidation through up-regulation of the mRNA level of ACO in the liver and white adipose tissue, which was likely mediated via up-regulation of the mRNA levels of PPARalpha.

Background & Aims Entecavir (ETV) is approved for the treatment of chronic hepatitis B virus (HBV) infections, but the virus can acquire resistance to the drug. This requires lamivudine resistance mutations (LAMr) and at least one additional mutation. Here, we characterized two novel mutations, rtI163V and rtA186T, associated with viral breakthrough (VBT) in an ETV-refractory patient. Methods HBV from an ETV-refractory patient was sequenced, and newly identified mutations were inserted into a replication-competent clone by mutagenesis. Clones were analyzed for replication efficacy and susceptibility to ETV in vitro . Chimeric mice with human hepatocytes were inoculated with the patient's serum at VBT, and monitored for viral mutation pattern using a next-generation sequencing approach. Results RtI163V and rtA186T mutations were detected together with LAMr (rtL180M and rtM204V) at VBT. RtA186T plus LAMr reduced susceptibility to ETV more than 111.1-fold compared with the wild-type clone, while rtI163V plus LAMr resulted in a 20.4-fold reduction. RtA186T significantly reduced viral replication efficacy, while the rtI163V mutation rescued it. Interestingly, the viral mutation pattern in the chimeric mice indicated dominant (or selective) proliferation of a clone containing rtI163V and rtA186T mutations plus LAMr under ETV treatment. Three-dimensional docking simulation indicated that rtA186T reduced the binding affinity of the HBV polymerase to ETV. Conclusions VBT in this ETV-refractory patient is attributable to the novel ETV resistance mutations rtI163V and rtA186T. RtA186T was apparently responsible for ETV resistance but the selection of a clone with the double mutation plus LAMr suggests that rtI163V is required to sustain viral fitness.

AIM: To investigate the acute effects of postprandial exercise on glucose and lipoprotein metabolism after the intake of glucose with or without fat cream in healthy but sedentary young women. METHODS: Healthy young Japanese women with a sedentary lifestyle, normal weight (18.5≤BMI

A 23-year-old nulliparous woman, a hepatitis B virus (HBV) carrier with stable liver functions, presented with exacerbation of viral replication (HBV DNA level9.0 log copies/mL) in gestational week 26. During the subsequent follow up without antiviral therapy, she was hospitalized with progression to hepatic failure in gestational week 35. Following initiation of antiviral therapy with lamivudine, emergent cesarean delivery was conducted for fetal safety. Liver atrophy and persistent hepatic encephalopathy (stage 2) necessitated artificial liver support (ALS) involving online hemodiafiltration (HDF) and plasma exchange. She regained full consciousness after the sixth online HDF session. ALS was terminated after the seventh online HDF session. On day 33 of hospitalization, she was discharged home without sequelae. Genetic analysis of the HBV strain isolated from her serum showed that this strain had genotype C. Direct full-length sequencing identified no known mutations associated with fulminant hepatitis B. HBV-related hepatic failure observed in the present case might have been related to perinatal changes in the host immune response.

Aim: To compare the acute effects of shortly pre- vs. postprandial exercise on postprandial lipid metabolism in healthy but sedentary young Japanese women.Methods: Healthy young Japanese women with a sedentary lifestyle, normal weight (18.5 ≤ BMI < 25), normal ovarian cycle, and apolipoprotein E3/3 were selected as participants. A single bout of walking exercise was performed 20 min after (Exp. 1) or 50 min before (Exp. 2) the intake of oral fat tolerance test (OFTT) cream (1 g/kg body weight) at about 50% Vo2max for 30 min on a motorized treadmill. A control trial without exercise was also performed in each experiment. Each subject performed 2 trials in a randomized, cross-over design. Venous blood samples were drawn before the preprandial exercise (−1 h, Exp. 1 only) and before (0 h) and 1, 2, 4 and 6 h after the fat intake for the determination of triglyceride (TG), apolipoprotein B-48 (apoB48), remnant-like particle-TG (RLP-TG), lactate, free fatty acid (FFA), insulin, and glucose.Results: In both experiments, postprandial serum TG concentrations in the exercise group were lower, but not significantly, than those in the control. In Exp. 1, incremental areas under the curve (IAUC) for TG and RLP-TG were slightly, but not significantly, smaller in the postprandial exercise group than the control. The values of apoB48, a marker of the chylomicron particle number, at 2, 4, and 6 h after the fat intake and IAUC for apoB48 were significantly lower in the postprandial exercise group than the control. In Exp. 2, IAUC for TG, RLP-TG, and apoB48 were not significantly different between the two groups.Conclusion: The present findings suggest that postprandial, but not preprandial, exercise may reduce the number of chylomicrons and chylomicron remnants and improve exogenous lipoprotein metabolism. Postprandial exercise is more effective for improving postprandial lipoprotein metabolism than preprandial exercise.

Background Obesity, especially visceral obesity, has been known to affect lipoprotein metabolism, but it is not clear whether obesity in young, apparently healthy men is associated with postprandial triglyceride-rich lipoprotein (TRL) metabolism. Methods Ten young normolipidemic, normoglycemic obese men (20.6 ± 0.5 y, BMI 27.5 ± 1.0 kg/m 2 ) and 11 lean healthy men (22.1 ± 0.4 y, 21.2 ± 0.4 kg/m 2 ) ingested OFTT cream (1 g/kg body weight). Fasting and postprandial blood samples were obtained for up to 6 h, and serum lipids and lipoproteins were analyzed. Results The obese men with a fasting triglyceride (TG) in the normal range and not different from the fasting value of lean controls had a prolonged postprandial response, indicated by a significantly greater incremental areas under the curve in serum TG, TRL-TG, and remnant-like particle-cholesterol (RLP-C) compared with controls. Plasma glucose levels did not change during the test. Differences in serum insulin levels and homeostasis model assessment-insulin resistance (HOMA-IR) were not statistically significant between the two groups; however, trends toward higher levels were shown in obese young men. Conclusions The obese young men showed significantly delayed TRL metabolism compared to the lean young men after fat loading, even though the obese men were normolipidemic. These results suggest the possibility that early insulin resistance in the obese young men may have caused the decrease of lipoprotein lipase activity and induced delayed TRL metabolism. A fat loading test without carbohydrate may provide a useful tool for the detection of delayed postprandial TRL metabolism and early insulin resistance.

A tyrosine kinase adaptor protein containing pleckstrin homology and SH2 domains (APS) is rapidly and strongly tyrosine phosphorylated by insulin receptor kinase upon insulin stimulation. The function of APS in insulin signaling has heretofore remained unknown. APS -deficient ( APS −/− ) mice were used to investigate its function in vivo. The blood glucose-lowering effect of insulin, as assessed by the intraperitoneal insulin tolerance test, was increased in APS −/− mice. Plasma insulin levels during fasting and in the intraperitoneal glucose tolerance test were lower in APS −/− mice. APS −/− mice showed an increase in the whole-body glucose infusion rate as assessed by the hyperinsulinemic-euglycemic clamp test. These findings indicated that APS −/− mice exhibited increased sensitivity to insulin. However, overexpression of wild-type or dominant-negative APS in 3T3L1 adipocytes did not affect insulin receptor numbers, phosphorylations of insulin receptor, insulin receptor substrate-1, or Akt and mitogen-activated protein kinase. The glucose uptake and GLUT4 translocation were not affected by insulin stimulation in these cells. Nevertheless, the insulin-stimulated glucose transport in isolated adipocytes of APS −/− mice was increased over that of APS +/+ mice. APS −/− mice also showed increased serum levels of leptin and adiponectin, which might explain the increased insulin sensitivity of adipocytes.