Identification of a distal enhancer that determines the expression pattern of acute phase marker C-reactive protein.

C-reactive protein (CRP) is a major acute phase protein and inflammatory marker, the expression of which is largely liver specific and highly inducible. Enhancers are regulatory elements critical for the precise activation of gene expression, yet the contributions of enhancers to the expression pattern of CRP have not been well defined. Here, we identify a constitutively active enhancer (E1) located 37.7 kb upstream of the promoter of human CRP in hepatocytes. By using chromatin immunoprecipitation, luciferase reporter assay, in situ genetic manipulation, CRISPRi, and CRISPRa, we show that E1 is enriched in binding sites for transcription factors STAT3 and C/EBP-ß and is essential for the full induction of human CRP during the acute phase. Moreover, we demonstrate that E1 orchestrates with the promoter of CRP to determine its varied expression across tissues and species through surveying activities of E1-promoter hybrids and the associated epigenetic modifications. These results thus suggest an intriguing mode of molecular evolution wherein expression-changing mutations in distal regulatory elements initiate subsequent functional selection involving coupling among distal/proximal regulatory mutations and activity-changing coding mutations.

Prior nasal delivery of antagomiR-122 prevents radiation-induced brain injury.

Radiation-induced brain injury is a major adverse event in head and neck tumor treatment, influencing the quality of life for the more than 50% of patients who undergo radiation therapy and experience long-term survival. However, no effective treatments are available for these patients, and preventative drugs and effective drug-delivery methods must be developed. Based on our results, miR-122-5p was upregulated in the mouse radiation-induced brain injury (RBI) model and patients with nasopharyngeal carcinoma (NPC) who received radiation therapy. Intranasal administration of a single antagomiR-122-5p dose before irradiation effectively alleviated radiation-induced cognitive impairment, neuronal injury, and neuroinflammation in the mouse RBI model. Results further indicated that miR-122-5p inhibition in microglia reduced the levels of proinflammatory cytokines and enhanced the phagocytic function to protect against radiation-induced neuronal injury in cell models. Further, we profiled transcriptome data and verified that Tensin 1 (TNS1) may be the target of miR-122-5p in RBI. In summary, our results reveal a distinct role for miR-122-5p in regulating neuroinflammation in RBI, indicating that a non-invasive strategy for intranasal miR-122-5p administration may be an attractive therapeutic target in RBI, providing new insights for clinical trials. Further systematic safety assessment, optimization of drug administration, and clarity of mechanism will accelerate the process into clinical practice.

Outer membrane vesicles enhance tau phosphorylation and contribute to cognitive impairment.

Outer membrane vesicles (OMVs) are nanosized vesicles produced by the gut microbiota (GM). The GM is well-known to be involved in the pathological process of Alzheimer's disease (AD). However, the mechanism of OMVs is not clear. In the present study, we demonstrated the involvement of OMVs in the development of cognitive (learning and memory) dysfunction induced by blood-brain barrier (BBB) disruption. More important, further study showed that OMVs induced tau phosphorylation by activating glycogen synthase kinase 3ß (GSK-3ß) in the hippocampus. OMVs activated astrocytes and microglia, increased secretion of inflammatory cytokines (nuclear factor κB, interleukin-1ß, and tumour necrosis factor-α) in the hippocampus. Therefore, OMVs increase the permeability of the BBB and promote the activation of astrocytes and microglia, inducing an inflammatory response and tau hyperphosphorylation by activating the GSK-3ß pathway and finally leading to cognitive impairment.

Comparison of laparoscopic and open radical hysterectomy in cervical cancer patients with tumor size ≤2 cm.

OBJECTIVE: There is recent evidence that demonstrates worse oncologic outcomes associated with minimally invasive radical hysterectomy when compared with open radical hysterectomy, particularly in patients with tumors >2 cm. The aim of our study was to retrospectively evaluate the oncological outcomes between laparoscopic and open radical hysterectomy in International Federation of Gynecology and Obstetrics(FIGO) 2009 stage IB1 (FIGO 2009) cervical cancer patients with tumor size ≤2 cm. METHODS: A retrospective review of medical records was performed to identify patients who underwent either laparoscopic or open radical hysterectomy during January 2010 and December 2018. Inclusion criteria were: (1) histologically confirmed cervical cancer including all histological types; (2) FIGO 2009 stage IB1; (3) tumor size ≤2 cm (determined by pelvic examination, magnetic resonance imaging or transvaginal ultrasound); (4) had undergone radical hysterectomy (type II or III) with pelvic and/or para-aortic lymphadenectomy as primary surgical treatment; (5) had follow-up information. Patients with FIGO 2009 stage IA1 or IA2, tumor size >2 cm, or who received neo-adjuvant chemotherapy before surgery, those with cervical cancer incidentally found after simple hysterectomy, or with insufficient data were excluded. Concurrent comparison between the laparoscopic and open cohorts was made for disease-free survival and overall survival. RESULTS: A total of 325 cervical cancer patients were included; of these, 129 patients underwent laparoscopic surgery and 196 patients had open surgery. The median follow-up times were 51.8 months (range 2-115) for laparoscopic surgery and 49.5 months (range 3-108) for open surgery. Patients in the laparoscopic group had significantly worse 5 year disease-free survival than those in the open group (90.4% vs 97.7%; p=0.02). There was no significant difference in 5 year overall survival between groups (96.9% vs 99.4%, p=0.33). The Cox proportional hazards regression analysis indicated that laparoscopic surgery was associated with lower disease-free survival compared with open surgery (adjusted hazard ratio 4.64, 95% CI 1.26 to 17.06; p=0.02). In patients with non-squamous cell carcinoma or with grade II-III, laparoscopic surgery had a significantly worse 5 year disease-free survival compared with the open surgery group (74% vs 100%, p=0.01, and 88.8% vs 98.0%, p=0.02, respectively). CONCLUSION: Laparoscopic radical hysterectomy was associated with worse disease-free survival for stage IB1 (FIGO 2009) cervical cancer patients with tumor size ≤2 cm compared with open radical hysterectomy. Further studies may shed additional light on the impact of minimally invasive surgery in this low-risk patient population.

Protection of Fecal Microbiota Transplantation in a Mouse Model of Multiple Sclerosis.

Given the growing evidence of a link between gut microbiota (GM) dysbiosis and multiple sclerosis (MS), fecal microbiota transplantation (FMT), aimed at rebuilding GM, has been proposed as a new therapeutic approach to MS treatment. To evaluate the viability of FMT for MS treatment and its impact on MS pathology, we tested FMT in mice with experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. We provide evidence that FMT can rectify altered GM to some extent with a therapeutic effect on EAE. We also found that FMT led to reduced activation of microglia and astrocytes and conferred protection on the blood-brain barrier (BBB), myelin, and axons in EAE. Taken together, our data suggest that FMT, as a GM-based therapy, has the potential to be an effective treatment for MS.

Plasma miR-1273g-3p acts as a potential biomarker for early Breast Ductal Cancer diagnosis.

Circulating miRNAs presenting in plasma in a stable manner have been demonstrated their potential role as a promising biomarkers in many human diseases, such as Alzheimer's disease, melanoma and ovarian carcinoma. However, few circulating miRNAs could be used for breast ductal cancer diagnosis. Here, we identified miR-1273g-3p as a biomarker for detecting breast ductal cancer. We detected miR-1273g-3p levels in the plasma of 39 sporadic breast ductal cancer patients and 40 healthy donors by Stem-loop Quantitative Real-time PCR (qRT-PCR). The results showed the plasma miR-1273g-3p level were significantly up-regulated in breast ductal cancer patients compared with healthy donors (p=0.0139). Receiver operating characteristic (ROC) curve also revealed the significantly diagnostic ability of miR-1273g-3p in patients (p=0.0414). In addition, the plasma level of miR-1273g-3p was closely related to IIIB-IIIC TNM stage. We also confirmed the higher expression level of miR-1273g-3p in breast cancer cell lines MCF-7 (4.872±0.537) than normal breast cells (Hs 578Bst). Taken together, miR-1273g-3p could represent as a potential biomarker for early breast ductal cancer diagnosis.

Spatial and temporal studies of metabolic activity: contrasting biochemical kinetics in tissues and pathways during fasted and fed states.

The regulation of nutrient homeostasis, i.e., the ability to transition between fasted and fed states, is fundamental in maintaining health. Since food is typically consumed over limited (anabolic) periods, dietary components must be processed and stored to counterbalance the catabolic stress that occurs between meals. Herein, we contrast tissue- and pathway-specific metabolic activity in fasted and fed states. We demonstrate that knowledge of biochemical kinetics that is obtained from opposite ends of the energetic spectrum can allow mechanism-based differentiation of healthy and disease phenotypes. Rat models of type 1 and type 2 diabetes serve as case studies for probing spatial and temporal patterns of metabolic activity via [2H]water labeling. Experimental designs that capture integrative whole body metabolism, including meal-induced substrate partitioning, can support an array of research surrounding metabolic disease; the relative simplicity of the approach that is discussed here should enable routine applications in preclinical models.

Role of apolipoprotein C-III overproduction in diabetic dyslipidaemia.

AIMS: To investigate how apolipoprotein C-III (apoC-III) metabolism is altered in subjects with type 2 diabetes, whether the perturbed plasma triglyceride concentrations in this condition are determined primarily by the secretion rate or the removal rate of apoC-III, and whether improvement of glycaemic control using the glucagon-like peptide-1 analogue liraglutide for 16 weeks modifies apoC-III dynamics. MATERIALS AND METHODS: Postprandial apoC-III kinetics were assessed after a bolus injection of [5,5,5-2 H3 ]leucine using ultrasensitive mass spectrometry techniques. We compared apoC-III kinetics in two situations: in subjects with type 2 diabetes before and after liraglutide therapy, and in type 2 diabetic subjects with matched body mass index (BMI) non-diabetic subjects. Liver fat content, subcutaneous abdominal and intra-abdominal fat were determined using proton magnetic resonance spectroscopy. RESULTS: Improved glycaemic control by liraglutide therapy for 16 weeks significantly reduced apoC-III secretion rate (561 ± 198 vs. 652 ± 196 mg/d, P = 0.03) and apoC-III levels (10.0 ± 3.8 vs. 11.7 ± 4.3 mg/dL, P = 0.035) in subjects with type 2 diabetes. Change in apoC-III secretion rate was significantly associated with the improvement in indices of glucose control (r = 0.67; P = 0.009) and change in triglyceride area under the curve (r = 0.59; P = 0.025). In line with this, the apoC-III secretion rate was higher in subjects with type 2 diabetes compared with BMI-matched non-diabetic subjects (676 ± 208 vs. 505 ± 174 mg/d, P = 0.042). CONCLUSIONS: The results reveal that the secretion rate of apoC-III is associated with elevation of triglyceride-rich lipoproteins in subjects with type 2 diabetes, potentially through the influence of glucose homeostasis on the production of apoC-III.

SRR intronic variation inhibits expression of its neighbouring SMG6 gene and protects against temporal lobe epilepsy.

D-serine is a predominant N-methyl-D-aspartate receptor co-agonist with glutamate, and excessive activation of the receptor plays a substantial role in epileptic seizures. Serine racemase (SRR) is responsible for transforming L-serine to D-serine. In this study, we aimed to investigate the genetic roles of SRR and a neighbouring gene, nonsense-mediated mRNA decay factor (SMG6), in temporal lobe epilepsy (TLE). Here, a total of 496 TLE patients and 528 healthy individuals were successfully genotyped for three SRR tag single nucleotide polymorphisms. The frequencies of the GG genotype at rs4523957 T > G were reduced in the TLE cases in the initial cohort (cohort 1) and were confirmed in the independent cohort (cohort 2). An analysis of all TLE cases in cohort 1 + 2 revealed that the seizure frequency and drug-resistant incidence were significantly decreased in carriers of the GG genotype at rs4523957. Intriguingly, the activity of the SMG6 promoter with the mutant allele at rs4523957 decreased by 22% in the dual-luciferase assay, and up-regulated expression of SMG6 was observed in an epilepsy rat model. This study provides the first demonstration that the GG genotype is a protective marker against TLE. In particular, variation at rs4523957 likely inhibits SMG6 transcription and plays a key role against susceptibility to and severity of TLE. The significance of SMG6 hyperfunction in epileptic seizures deserves to be investigated in future studies.

HMGB1 contributes to the irradiation-induced endothelial barrier injury through receptor for advanced glycation endproducts (RAGE).

This study aimed to investigate whether HMGB1 (high mobility group box-1 protein) and receptor for advanced glycation end products (RAGE) were involved in the irradiation-induced endothelial barrier damage and their mechanism. We constructed the damage model of endothelium barrier model with bEnd.3 cells. The permeability of endothelial barrier was detected by sodium fluorescein (Na-F) permeation test, and the irradiation dose which could induce permeability transition was determined by being exposed to different irradiation doses (5, 10, 15, 20 Gy). MTT assay was applied to detect cell viability under different concentrations of HMGB1, glycyrrhizic acid (GA, a specific inhibitor of HMGB1), and FPS-ZM1 (a blood-brain-barrier permeant blocker of RAGE V domain-mediated ligand binding). The expression of HMGB1, RAGE, and related molecules involved in MAPK signaling pathway, MMP-2, MMP-9, ZO-1, and claudin 5 of differently treated groups were measured by qRT-PCR, western blot, and immunofluorescence. Cells possessed stable endothelial barrier function on 4-7 days after seeded on transwell plates. The permeability of endothelial barrier would change under at least 10 Gy radiation. Both radiation and HMGB1 treatment alone could improve the permeability. After irradiation, the expressions of HMGB1 and RAGE increased and MAPK signal pathway was activated. Meanwhile, MMP-2 and MMP-9 were overexpressed, while the expression of tight junction proteins ZO-1 and claudin 5 was decreased. Radiation could activate MAPK signaling pathway through promoting the expression of HMGB1 and RAGE, which further led to endothelial barrier injury and changed its permeability.

Association of APEX1 and OGG1 gene polymorphisms with breast cancer risk among Han women in the Gansu Province of China.

BACKGROUND: Genetic variations in key DNA repair genes may influence DNA repair capacity, DNA damage and breast carcinogenesis. The current study aimed to estimate the association of APEX1 and OGG1 polymorphisms with the risk of breast cancer development. METHODS: A total of 518 patients with histopathologically confirmed breast cancer and 921 region- and age-matched cancer-free controls were genotyped for the APEX1 polymorphisms rs3136817 and rs1130409 and the OGG1 polymorphisms rs1052133 and rs2072668 using a QuantStudio™ 12 K Flex Real-Time PCR System. RESULTS: The rs3136817 heterozygous TC genotype along with the rs3136817 dominant model (TC + CC) was strongly associated with breast cancer susceptibility (odds ratio [OR] = 0.670, 95% confidence interval [95% CI]: 0.513 - 0.873, P = 0.003; OR = 0.682, 95% CI: 0.526 - 0.883, P = 0.004, respectively). No significant associations were observed among rs1130409, rs1052133, rs2072668 and breast cancer risk. Furthermore, an allele combination analysis revealed that APEX1 haplotypes containing C-T (alleles rs3136817 and rs1130409) conferred a significantly lower risk (corrected P < 0.001). CONCLUSION: This research is the latest report showing that an APEX1 rs3136817 heterozygous genotype may have a positive influence on DNA repair capacity in patients with breast cancer and thus may have a potential protective effect for Chinese Han women.

CETP (Cholesteryl Ester Transfer Protein) Inhibition With Anacetrapib Decreases Production of Lipoprotein(a) in Mildly Hypercholesterolemic Subjects.

OBJECTIVE: Lp(a) [lipoprotein (a)] is composed of apoB (apolipoprotein B) and apo(a) [apolipoprotein (a)] and is an independent risk factor for cardiovascular disease and aortic stenosis. In clinical trials, anacetrapib, a CETP (cholesteryl ester transfer protein) inhibitor, causes significant reductions in plasma Lp(a) levels. We conducted an exploratory study to examine the mechanism for Lp(a) lowering by anacetrapib. APPROACH AND RESULTS: We enrolled 39 participants in a fixed-sequence, double-blind study of the effects of anacetrapib on the metabolism of apoB and high-density lipoproteins. Twenty-nine patients were randomized to atorvastatin 20 mg/d, plus placebo for 4 weeks, and then atorvastatin plus anacetrapib (100 mg/d) for 8 weeks. The other 10 subjects were randomized to double placebo for 4 weeks followed by placebo plus anacetrapib for 8 weeks. We examined the mechanisms of Lp(a) lowering in a subset of 12 subjects having both Lp(a) levels >20 nmol/L and more than a 15% reduction in Lp(a) by the end of anacetrapib treatment. We performed stable isotope kinetic studies using 2H3-leucine at the end of each treatment to measure apo(a) fractional catabolic rate and production rate. Median baseline Lp(a) levels were 21.5 nmol/L (interquartile range, 9.9-108.1 nmol/L) in the complete cohort (39 subjects) and 52.9 nmol/L (interquartile range, 38.4-121.3 nmol/L) in the subset selected for kinetic studies. Anacetrapib treatment lowered Lp(a) by 34.1% (P≤0.001) and 39.6% in the complete and subset cohort, respectively. The decreases in Lp(a) levels were because of a 41% reduction in the apo(a) production rate, with no effects on apo(a) fractional catabolic rate. CONCLUSIONS: Anacetrapib reduces Lp(a) levels by decreasing its production. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00990808.

Enhancing Studies of Pharmacodynamic Mechanisms via Measurements of Metabolic Flux: Fundamental Concepts and Guiding Principles for Using Stable Isotope Tracers.

Drug discovery and development efforts are largely based around a common expectation, namely, that direct or indirect action on a cellular process (e.g., statin-mediated enzyme inhibition or insulin-stimulated receptor activation) will have a beneficial impact on physiologic homeostasis. To expand on this, one could argue that virtually all pharmacologic interventions attempt to influence the flow of "traffic" in a biochemical network, irrespective of disease or modality. Since stable isotope tracer kinetic methods provide a measure of traffic flow (i.e., metabolic flux), their inclusion in study designs can yield novel information regarding pathway biology; the application of such methods requires the integration of knowledge in physiology, analytical chemistry, and mathematical modeling. Herein, we review the fundamental concepts that surround the use of tracer kinetics, define basic terms, and outline guiding principles via theoretical and experimental problems. Specifically, one needs to 1) recognize the types of biochemical events that change isotopic enrichments, 2) appreciate the distinction between fractional turnover and flux rate, and 3) be aware of the subtle differences between tracer kinetics and pharmacokinetics. We hope investigators can use the framework presented here to develop applications that address their specific questions surrounding biochemical flux, and thereby gain insight into the pathophysiology of disease states, and examine pharmacodynamic mechanisms.

Achieving efficient digestion faster with Flash Digest: potential alternative to multi-step detergent assisted in-solution digestion in quantitative proteomics experiments.

RATIONALE: In quantitative analysis of protein biomarkers and therapeutic proteins by liquid chromatography/mass spectrometry (LC/MS), it is a preferred and well-established approach to digest with proteolytic enzymes to produce smaller peptide fragments which are more suitable for LC/MS analysis than the intact protein. In-solution digestion is one widely used method for protein digestion. Proteolytically resistant proteins often require digestion times that extend beyond normal working hours and prohibit same day analysis. We evaluated the performance of an immobilized enzyme reactor (IMER) to determine if this technology could reduce method development time, digestion time and increase throughput. METHODS: We digested human plasma samples using a commercially available IMER, Flash Digest, and compared it to an in-solution digestion method for analysis of three different apolipoprotein biomarkers APOE, APOC2, and APOC3. The plasma digests were analyzed via LC/MS using electrospray ionization (ESI) and multiple reaction monitoring (MRM). Value assigned calibrators were selected over a relevant physiological concentration range for each protein of interest. Quality control samples (QCs) and 'unknown' human plasma samples were analyzed with both methods. RESULTS: Flash Digest significantly reduced digestion time for APOC3, the most proteolytically resistant of the three proteins, to 30 min compared with overnight used with in-solution digestion. The Flash Digest achieved comparable digestion efficiency with minimal method development and reduced sample preparation time. Both methods showed linearity over a physiologically relevant concentration range. Precision was evaluated and a percentage coefficient of variance (% CV) less than 8% was obtained during intra-day reproducibility evaluation for all three apolipoproteins with Flash Digest. Concentrations observed for QCs and unknown samples using Flash Digest were comparable to the in-solution method. CONCLUSIONS: An IMER such as Flash Digest may be a potential alternative to in-solution digestion to accelerate digestion of proteolytically resistant proteins in a quantitative proteomics experiments, reduce method development time and increase throughput. Copyright © 2016 John Wiley & Sons, Ltd.

Intranasal Delivery of miR-146a Mimics Delayed Seizure Onset in the Lithium-Pilocarpine Mouse Model.

Unveiling the key mechanism of temporal lobe epilepsy (TLE) for the development of novel treatments is of increasing interest, and anti-inflammatory miR-146a is now considered a promising molecular target for TLE. In the current study, a C57BL/6 TLE mouse model was established using the lithium-pilocarpine protocol. The seizure degree was evaluated according to the Racine scale, and level 5 was considered the threshold for generalized convulsions. Animals were sacrificed to analyze the hippocampus at three time points (2 h and 4 and 8 weeks after pilocarpine administration to evaluate the acute, latent, and chronic phases, resp.). After intranasal delivery of miR-146a mimics (30 min before pilocarpine injection), the percent of animals with no induced seizures increased by 6.7%, the latency to generalized convulsions was extended, and seizure severity was reduced. Additionally, hippocampal damage was alleviated. While the relative miR-146a levels significantly increased, the expression of its target mRNAs (IRAK-1 and TRAF-6) and typical inflammatory modulators (NF-κB, TNF-α, IL-1ß, and IL-6) decreased, supporting an anti-inflammatory role of miR-146a via the TLR pathway. This study is the first to demonstrate that intranasal delivery of miR-146a mimics can improve seizure onset and hippocampal damage in the acute phase of lithium-pilocarpine-induced seizures, which provides inflammation-based clues for the development of novel TLE treatments.

Plasma Levels of Risk-Variant APOL1 Do Not Associate with Renal Disease in a Population-Based Cohort.

Two common missense variants in APOL1 (G1 and G2) have been definitively linked to CKD in black Americans. However, not all individuals with the renal-risk genotype develop CKD, and little is known about how APOL1 variants drive disease. Given the association of APOL1 with HDL particles, which are cleared by the kidney, differences in the level or quality of mutant APOL1­HDL particles could be causal for disease and might serve as a useful risk stratification marker. We measured plasma levels of G0 (low risk), G1, and G2 APOL1 in 3450 individuals in the Dallas Heart Study using a liquid chromatography-MS method that enabled quantitation of the different variants. Additionally, we characterized native APOL1­HDL from donors with no or two APOL1 risk alleles by size-exclusion chromatography and analysis of immunopurified APOL1­HDL particles. Finally, we identified genetic loci associated with plasma APOL1 levels and tested for APOL1-dependent association with renal function. Although we replicated the previous association between APOL1 variant status and renal function in nondiabetic individuals, levels of circulating APOL1 did not associate with microalbuminuria or GFR. Furthermore, the size or known components of APOL1­HDL did not consistently differ in subjects with the renal-risk genotype. Genetic association studies implicated variants in loci harboring haptoglobin-related protein (HPR), APOL1, and ubiquitin D (UBD) in the regulation of plasma APOL1 levels, but these variants did not associate with renal function. Collectively, these data demonstrate that the risk of renal disease associated with APOL1 is probably not related to circulating levels of the mutant protein.

Multiplexed Quantification of Proglucagon-Derived Peptides by Immunoaffinity Enrichment and Tandem Mass Spectrometry after a Meal Tolerance Test.

BACKGROUND: Proglucagon-derived peptides (PGDPs), which include glucagon-like peptide (GLP)-1, glucagon, and oxyntomodulin, are key regulators of glucose homeostasis and satiety. These peptide hormones are typically measured with immuno-based assays (e.g., ELISA, RIA), which often suffer from issues of selectivity. METHODS: We developed a multiplexed assay for measuring PGDPs including GLP-1 (7-36) amide, GLP-1 (9-36) amide, glucagon, and oxyntomodulin by mass spectrometry and used this assay to examine the effect of a meal tolerance test on circulating concentrations of these hormones. Participants fasted overnight and were either given a meal (n = 8) or continued to fast (n = 4), with multiple blood collections over the course of 3 h. Plasma samples were analyzed by microflow immunoaffinity (IA)-LC-MS/MS with an isotope dilution strategy. RESULTS: Assay performance characteristics were examined and established during analytical validation for all peptides. Intra- and interassay imprecision were found to be 2.2%-10.7% and 6.8%-22.5%, respectively. Spike recovery was >76%, and dilution linearity was established up to a 16-fold dilution. Immediately after the meal tolerance test, GLP-1 and oxyntomodulin concentrations increased and had an almost identical temporal relationship, and glucagon concentrations increased with a slight delay. CONCLUSIONS: IA-LC-MS/MS was used for the simultaneous and selective measurement of PGDPs. This work includes the first indication of the physiological concentrations and modulation of oxyntomodulin after a meal.

[Mechanism of geniposide in improving free fatty acid metabolism in rats with non-alcoholic fatty liver disease].

To observe the effect of geniposide on non-alcoholic fatty liver disease (NAFLD), and discuss the mechanism of geniposide for NAFLD from the aspect of free fatty acid, forty healthy Wistar male rats were randomly divided into normal group, model group, geniposide and Xuezhikang group. The rats in normal group were fed with normal diets, and the rats in other 3 groups were given with high-fat diet for 8 weeks to induce the NAFLD models. From the week 5 to end of week 8, the rats in geniposide and Xuezhikang group were intervened with corresponding medicines. The body weight, liver wet weight, and fat weight of the rats were recorded. Visual and pathological changes in hepatic tissues were observed with HE staining. The contents of TG, FFA, FAS, AMPK, ACCase and Malonyl-CoA in hepatic tissue, contents of CHO and LDL-C in serum and activities of AST and ALT in serum were detected by using corresponding methods. The results showed that the body weight, liver wet weight, and fat weight of the rats, CHO, LDL-C, ALT and AST levels in serum, TG, FFA, FAS, ACCase and Malonyl-CoA levels in hepatic tissues of the rats in model group were significantly higher than those in normal group (P<0.01), while AMPK activity was significantly lower than that of the normal group (P<0.01), with obvious visual and pathological steatosis in hepatic tissues, and inflammatory injury occurred in model group. Compared with the model group, body weight of the rat, fat weight, levels of FFA in hepatic tissues, ALT and AST activities in serum, liver wet weight, TG, FAS, ACCase and Malonyl-CoA levels were significantly decreased in geniposide group (P<0.01), while the AMPK activity in hepatic tissues was significantly increased (P<0.05),with improvement in visual and pathological performance. Compared with the model group, liver wet weight, fat weight, TG and FFA levels in hepatic tissues, and LDL-C level in serum were significantly decreased in Xuezhikang group (P<0.05). Compared with Xuezhikang group, the body weight of rat, fat weight and FFA level in hepatic tissues were significantly lower in geniposide group (P<0.01), but with no significant difference in other aspects. These findings indicated that geniposide was highly effective in improving the pharmacological effect of NAFLD induced by high-fat diet, and the mechanism was achieved through AMPK-ACCase-Malonyl-CoA-FFA axis.

New methodologies for studying lipid synthesis and turnover: looking backwards to enable moving forwards.

Our ability to understand the pathogenesis of problems surrounding lipid accretion requires attention towards quantifying lipid kinetics. In addition, studies of metabolic flux should also help unravel mechanisms that lead to imbalances in inter-organ lipid trafficking which contribute to dyslipidemia and/or peripheral lipid accumulation (e.g. hepatic fat deposits). This review aims to outline the development and use of novel methods for studying lipid kinetics in vivo. Although our focus is directed towards some of the approaches that are currently reported in the literature, we include a discussion of the older literature in order to put "new" methods in better perspective and inform readers of valuable historical research. Presumably, future advances in understanding lipid dynamics will benefit from a careful consideration of the past efforts, where possible we have tried to identify seminal papers or those that provide clear data to emphasize essential points. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.

Tracer-based estimates of protein flux in cases of incomplete product renewal: evidence and implications of heterogeneity in collagen turnover.

The synthesis of various molecules can be estimated by measuring the incorporation of a labeled precursor into a product of interest. Unfortunately, a central problem in many studies has been an inability to estimate the intracellular dilution of the precursor and therein correctly calculate the synthesis of the product; it is generally assumed that measuring the true product labeling is straightforward. We initiated a study to examine liver collagen synthesis and identified an apparent problem with assumptions regarding measurements of the product labeling. Since it is well known that collagen production is relatively slow, we relied on the use of [(2)H]H2O labeling (analogous to a primed infusion) and sampled animals over the course of 16 days. Although the water labeling (the precursor) remained stable and we observed the incorporation of labeled amino acids into collagen, the asymptotic protein labeling was considerably lower than what would be expected based on the precursor labeling. Although this observation is not necessarily surprising (i.e., one might expect that a substantial fraction of the collagen pool would appear "inert" or turn over at a very slow rate), its implications are of interest in certain areas. Herein, we discuss a novel situation in which tracers are used to quantify rates of flux under conditions where a product may not undergo complete replacement. We demonstrate how heterogeneity in the product pool can lead one to the wrong conclusions regarding estimates of flux, and we outline an approach that may help to minimize errors surrounding data interpretation.