Fasting Healthy Subjects Research Articles

Feeding enhances fibronectin adherence of quiescent lymphocytes through non-canonical insulin signalling.

Nutritional availability during fasting and refeeding affects the temporal redistribution of lymphoid and myeloid immune cells among the circulating and tissue-resident pools. Conversely, nutritional imbalance and impaired glucose metabolism are associated with chronic inflammation, aberrant immunity and anomalous leukocyte trafficking. Despite being exposed to periodic alterations in blood insulin levels upon fasting and feeding, studies exploring the physiological effects of these hormonal changes on quiescent immune cell function and trafficking are scanty. Here, we report that oral glucose load in mice and healthy men enhances the adherence of circulating peripheral blood mononuclear cells (PBMCs) and lymphocytes to fibronectin. Adherence to fibronectin is also observed upon regular intake of breakfast following overnight fasting in healthy subjects. This glucose load-induced phenomenon is abrogated in streptozotocin-injected mice that lack insulin. Intra-vital microscopy in mice demonstrated that oral glucose feeding enhances the homing of PBMCs to injured blood vessels in vivo. Furthermore, employing flow cytometry, Western blotting and adhesion assays for PBMCs and Jurkat-T cells, we elucidate that insulin enhances fibronectin adherence of quiescent lymphocytes through non-canonical signalling involving insulin-like growth factor-1 receptor (IGF-1R) autophosphorylation, phospholipase C gamma-1 (PLCγ-1) Tyr783 phosphorylation and inside-out activation of β-integrins respectively. Our findings uncover the physiological relevance of post-prandial insulin spikes in regulating the adherence and trafficking of circulating quiescent T-cells through fibronectin-integrin interaction.

Acute effects of a single moderate-intensity exercise bout performed in fast or fed states on cell metabolism and signaling: Comparison between lean and obese rats

AimsAlthough the benefits of exercise can be potentiated by fasting in healthy subjects, few studies evaluated the effects of this intervention on the metabolism of obese subjects. This study investigated the immediate effects of a single moderate-intensity exercise bout performed in fast or fed states on the metabolism of gastrocnemius and soleus of lean and obese rats. Main methodsMale rats received a high-fat diet (HFD) for twelve weeks to induce obesity or were fed standard diet (SD). After this period, the animals were subdivided in groups: fed and rest (FER), fed and exercise (30 min treadmill, FEE), 8 h fasted and rest (FAR) and fasted and exercise (FAE). Muscle samples were used to investigate the oxidative capacity and gene expression of AMPK, PGC1α, SIRT1, HSF1 and HSP70. Key findingsIn relation to lean animals, obese animals' gastrocnemius glycogen decreased 60 %, triglycerides increased 31 %; glucose and alanine oxidation decreased 26 % and 38 %, respectively; in soleus, triglycerides reduced 46 % and glucose oxidation decreased 37 %. Exercise and fasting induced different effects in glycolytic and oxidative muscles of obese rats. In soleus, fasting exercise spared glycogen and increased palmitate oxidation, while in gastrocnemius, glucose oxidation increased. In obese animals' gastrocnemius, AMPK expression decreased 29 % and SIRT1 increased 28 % in relation to lean. The AMPK response was more sensitive to exercise and fasting in lean than obese rats. SignificanceExercise and fasting induced different effects on the metabolism of glycolytic and oxidative muscles of obese rats that can promote health benefits in these animals.

Pharmacokinetic Comparison and Bioequivalence Evaluation between a Newly Formulated Generic and the Brand Cefuroxime Axetil Tablets in Healthy Male Adult Fasting Subjects

Cefuroxime axetil (CA) is a broad-spectrum second-generation cephalosporin antibiotic resistant to beta-lactamase used for treating different kinds of infections. This study was conducted to compare the pharmacokinetics (PK) and to evaluate the bioequivalence (BE) between a newly formulated generic CA 500mg tablets as a test formula with the same dose of the brand formula as the reference product applying 2-way, 2-treatment, 2-period, 2-sequence, randomized crossover design with six days washout interval between dosing. After overnight fasting for 12 hours, both CA products were administered to 28 healthy male adult Arabic subjects, followed by serial blood samples obtained from each subject before drug dosing (0-hr) and then up to 8 hours post-dosing. The calculated PK parameters Cmax, Tmax, AUC0–t, AUC0–∞, Thalf, MRT, Cl and Vd obtained from each product were statistically compared by ANOVA and 90% confidence interval tests to evaluate the BE between both products. Based on international guidance on bioequivalences like FDA and EMEA, it was concluded from this research that the test and the reference formulas are bioequivalent since the 90% confidence intervals were within the accepted ranges of 80.00-125.00%. All participants tolerated both products well, and they were discharged without any significant alterations in their clinical baseline characteristics. Therefore, the newly formulated generic CA 500mg tablets may be prescribed in clinical practice and used as a safe and effective alternative to the brand product.

A macrophage-hepatocyte glucocorticoid receptor axis coordinates fasting ketogenesis

Fasting metabolism and immunity are tightly linked; however, it is largely unknown how immune cells contribute to metabolic homeostasis during fasting in healthy subjects. Here, we combined cell-type-resolved genomics and computational approaches to map crosstalk between hepatocytes and liver macrophages during fasting. We identified the glucocorticoid receptor (GR) as a key driver of fasting-induced reprogramming of the macrophage secretome including fasting-suppressed cytokines and showed that lack of macrophage GR impaired induction of ketogenesis during fasting as well as endotoxemia. Mechanistically, macrophage GR suppressed the expression of tumor necrosis factor (TNF) and promoted nuclear translocation of hepatocyte GR to activate a fat oxidation/ketogenesis-related gene program, cooperatively induced by GR and peroxisome proliferator-activated receptor alpha (PPARα) in hepatocytes. Together, our results demonstrate how resident liver macrophages directly influence ketogenesis in hepatocytes, thereby also outlining a strategy by which the immune system can set the metabolic tone during inflammatory disease and infection.

Effects of Meal Fructose/Glucose Composition on Postprandial Glucose Appearance and Hepatic Glycogen Synthesis in Healthy Subjects.

Dietary fructose overshadows glucose in promoting metabolic complications. Intestinal fructose metabolism (IFM) protects against these effects in rodents, by favoring gluconeogenesis, but the extent of IFM in humans is not known. We therefore aimed to infer the extent of IFM by comparing the contribution of dietary fructose to systemic glucose and hepatic glycogen appearance postprandially. Twelve fasting healthy subjects ingested two protein meals in random order, one supplemented with 50 g 5/95 fructose/glucose (LF) and the other with 50 g 55/45 fructose/glucose (HF). Sources of postprandial plasma glucose appearance and hepatic glycogen synthesis were determined with deuterated water. Plasma glucose excursions, as well as pre- and post-meal insulin, c-peptide, and triglyceride levels were nearly identical for both meals. The total gluconeogenic contribution to plasma glucose appearance was significantly higher for HF versus LF (65 ± 2% vs. 34 ± 3%, p < 0.001). For HF, Krebs cycle anaplerosis accounted for two-thirds of total gluconeogenesis (43 ± 2%) with one-third from Triose-P sources (22 ± 1%). With LF, three-quarters of the total gluconeogenic contribution originated via Krebs cycle anaplerosis (26 ± 2%) with one-quarter from Triose-P sources (9 ± 2%). HF and LF gave similar direct and indirect pathway contributions to hepatic glycogen synthesis. Increasing the fructose/glucose ratio had significant effects on glucose appearance sources but no effects on hepatic glycogen synthesis sources, consistent with extensive IFM. The majority of fructose carbons were converted to glucose via the Krebs cycle.

Effect of Fasting on Intraocular Pressure

Purpose: To determine the effect of fasting on intraocular pressure in fasting individuals.&#x0D; Study Design: Cross sectional observational study.&#x0D; Place and Duration of Study: District Headquarter Teaching Hospital/Sahiwal Medical College Sahiwal, from April 2020 to May 2020.&#x0D; Methods: Four hundred eyes of two hundred healthy fasting subjects were included in this study. Intraocular pressure was measured one week before and during the second week of Ramadan. t-test was used to calculate the difference of means of intraocular pressure one week before and during the second week of Ramadan.&#x0D; Results: Mean age of the subjects was 34.56 ± 12.52 years. IOP in male subjects before and during Ramadan was 14.23 mmHg and 13.20 mmHg respectively, while IOP in female subjects before and during Ramadan was 14.43 mmHg and 13.20 mmHg respectively. Before Ramadan mean intraocular pressure in the right eye was 14.38 ± 3.00 mmHg and in the left eye was 14.21 ± 2.79 mmHg. During Ramadan mean intraocular pressure in the right eye was 13.24 ± 2.87 mmHg and in the left eye was 13.15 ± 2.71 mmHg. t-test indicated that the difference in means of intraocular pressure for right eye one week before and during the second week of Ramadan was 25.74 (p = 0.000). Similarly, the difference in means of intraocular pressure for left eye one week before and during the second week of Ramadan was 41.54 (p = 0.000).&#x0D; Conclusion: Fasting results in a decrease in intraocular pressure in normal population. There was no difference in intraocular pressure changes between male and female subjects. Intraocular Pressure was higher in older age group in both genders.&#x0D; Key Words: Intraocular Pressure, Tonometry, Glaucoma.

The effect of religious fasting and dehydration at Ramadan on choroidal thickness and Retinal vessel densities, measured with optical coherence tomography angiography.

To investigate the effect of religious fasting and dehydration at Ramadan on choroidal thickness and vessel density in the superficial and deep vascular plexuses with OCTA. The choroidal thickness, and superficial and deep vessel density indices of fasting healthy subjects were measured with an OCTA device, and compared with non-fasting measurements. The study included 70 eyes of 35 healthy subjects with a mean age of 42.86 ± 8.3 years. The measured choroidal thickness, superficial vessel density index and deep vessel density index were 288.89 ± 67 µm, 40.56% and 41.43%, respectively when measured in the fasting period, compared to 284.62 ± 65 µm, 40.41% and 41.41%, respectively when measured in the non-fasting period. The choroidal thickness under the fovea center was found to be significantly higher in the fasting period than in the non-fasting period (p = 0.014). The mean total choroidal thickness was found to be reduced in the non-fasting period, although not to a statistically significant degree (p > 0.05). An analysis of the mean total superficial and deep vascular plexuses revealed no statistically significant difference (p = 0.368, p = 0.938 respectively). Although a significant increase was noted in central choroidal thickness in the fasting period, no significant change due to fasting was observed in the superficial and deep capillary plexuses. The choroidal layer may vary in thickness due to fasting-related metabolic factors, while retinal vessels are more stable against such effects.

Circulating levels of the components of the GH/IGF-1/IGFBPs axis total and intact IGF-binding proteins (IGFBP) 3 and IGFBP 4 and total IGFBP 5, as well as PAPPA, PAPPA2 and Stanniocalcin-2 levels are not altered in response to energy deprivation and/or metreleptin administration in humans

ObjectiveIt remains unclear whether food deprivation induces changes in components of the GH/IGF-1/IGFBPs axis and if yes, which ones are mediated by leptin, an adipocyte secreted hormone regulating neuroendocrine response to energy deprivation in animals and humans. We aimed to investigate components of the axis that have not been studied to date, i.e. IGF-binding proteins (IGFBPs) and related proteases (total and intact IGFBP 3 and IGFBP 4, total IGFBP 5, PAPPA, PAPPA2 and Stanniocalcin-2), during acute (short-term fasting in healthy subjects) and chronic (women with hypothalamic amenorrhea [HA] due to excessive exercise) energy deprivation and whether metreleptin administration, in replacement, supraphysiologic or pharmacologic levels, may mediate any changes of circulating levels of the above molecules in healthy individuals and in women with hypothalamic amenorrhea. MethodsWe studied: 1) 11 healthy men and women during three four day admissions i.e. a baseline admission in the fed isocaloric state and two admissions in the complete food deprivation state for 72-h with either placebo (resulting in a hypoleptinemic state) or metreleptin administration in doses designed to normalize circulating leptin levels for the duration of the study, 2) 15 healthy men and women during three 72-hour long admissions in a complete food deprivation state receiving three escalating doses of metreleptin designed to bring circulating leptin levels to physiologic, supraphysiologic, or pharmacologic levels, and 3) 18 women with HA randomized to either metreleptin treatment in replacement doses or placebo for nine months. ResultsThere were no significant changes in the circulating profiles of the above molecules in the fasting vs. fed state and/or with metreleptin administration during acute and chronic energy deprivation. ConclusionsThe studied components of the GH/IGF-1/IGFBPs axis are not affected by energy deprivation, leptin deficiency associated with energy deprivation, or by metreleptin administration in physiologic, supraphysiologic or pharmacologic doses.

Chewing gum for 1 h does not change gastric volume in healthy fasting subjects. A prospective observational study

Study objectivePerioperative fasting guidelines differ in their approaches to chewing gum in the preoperative period. Current recommendations range from canceling the surgery to proceeding with it. Given this lack of consensus, we performed gastric ultrasound assessments in healthy volunteers before and after a standardized period of chewing gum. The objective of our study was to determine if chewing gum for 1 h change the gastric volume. DesignObservational prospective analytical study. SettingBedside gastric ultrasound. PatientsFollowing institutional Review Board approval, 55 healthy (American Society of Anesthesiologists class I to II) fasted (non-surgical research) volunteers provided written informed consent to participate in the study. Morbid obesity, renal failure, diabetes mellitus, pregnancy and previous upper abdominal surgery were exclusion criteria. InterventionsVolunteers chewed gum for 1 h between the first and second assessment. MeasurementsFour gastric ultrasound assessments were performed, the first one at baseline and then hourly thereafter. Main resultsFifty-five healthy volunteers were studied. The proportion of subjects who presented a completely empty stomach (Grade 0 antrum) was similar at baseline and after 1 h of gum-chewing [81% vs. 84%, p = 0.19, CI 95% (−12%, 16%)]. Among those subjects who had visible fluid at baseline, the volume remained unchanged throughout the study period. ConclusionsOne hour of gum-chewing had no significant effect on the gastric fluid volume of healthy volunteers, suggesting that it may be safe for healthy subjects to chew gum prior to elective surgery.

Glucose Metabolism after Overnight and Prolonged Fasting in Healthy Subjects

Background: It is well known that the metabolic regulation of glucose can be influenced by dietary interventions, including alterations in meal timing. Aim of our analysis was to examine the glucose metabolism after an overnight fast (10 hours) and after prolonged fasting (36 hours of fasting). Material and Methods: Glucose metabolism was assessed by a 75 g oral glucose tolerance test after an overnight fasting period of 10 hours and a fasting period of 36h. Beta-cell function was quantified by 1st and 2nd phase insulin secretion indices. Results: We included 37 healthy subjects (mean age 48±10 years; 54% women) with a mean body mass index (BMI) of 25.2±3.4 kg/m2. After prolonged fasting mean 2h-glucose and AUC for glucose value were significantly higher than after 10h fasting (2h-glucose: 110±27 mg/dL vs. 89±24 mg/dL; p&amp;lt;0.001) (AUCglucose: 5336±3302 mg/dL/min vs. 3692±2266 mg/dL/min; p=0.002). First (745±500 vs. 982±573; p=0.012) and second phase insulin secretion (211 ± 115 vs. 266 ± 132; p=0.011) were significantly lower after 36h of fasting as compared to an overnight fast. Estimates for insulin sensitivity are similar after 10 and 36 hours of fasting. Conclusion: Our data demonstrate higher glucose excursions and a reduced insulin response after a 36 hour fasting period as compared to an overnight fasting period in healthy subjects.After 10h fastingAfter 36h fastingp-valueFasting c-peptide (ng/mL)1.39 ± 0.651.09 ± 1.030.025Fasting insulin (mU/L)7.9 ± 5.15.7 ± 5.80.042Fasting glucose (mg/dL)88 ± 988 ± 180.830Insulin after 60min (mU/L)87.6 ± 85.853.4 ± 51.80.0361st phase insulin secretion982 ± 573745 ± 5000.012HOMA-IR1.75 ± 1.181.39 ± 2.070.303Stumvoll index (ISI)0.10 ± 0.030.09 ± 0.03 0.230 Disclosure N.J. Tripolt: None. S. Stekovic: None. J. Url: None. F. Aberer: None. P.N. Pferschy: None. R. Riedl: None. B.M. Obermayer-Pietsch: None. T.R. Pieber: Consultant; Self; Arecor, AstraZeneca, Eli Lilly and Company, Novo Nordisk A/S, Sanofi. Employee; Self; CBmed. Research Support; Self; Novo Nordisk A/S, AstraZeneca. F. Madeo: None. H. Sourij: Speaker's Bureau; Self; Boehringer Ingelheim GmbH, Novo Nordisk A/S, Amgen Inc., Sanofi, MSD K.K.. Research Support; Self; AstraZeneca, Boehringer Ingelheim GmbH, MSD K.K., GI Dynamics Inc..

Prospects and limitations of antibody-mediated clearing of lipoproteins from blood plasma prior to nanoparticle tracking analysis of extracellular vesicles

ABSTRACTIntroduction: Nanoparticle tracking analysis (NTA) enables measurement of extracellular vesicles (EVs) but lacks the ability to distinct between EVs and lipoproteins which are abundantly present in blood plasma. Limitations in ultracentrifugation and size exclusion chromatography applied for EV isolation may result in inadequate EV purification and preservation. In this proof of concept study, we aimed to evaluate the potential of antibody-mediated removal of lipoproteins from plasma prior to extracellular vesicle (EV) analysis by nanoparticle tracking analysis (NTA).Methods: Ten platelet-free plasma (PFP) samples from healthy fasting subjects were incubated with magnetic beads coated with antibodies against apolipoprotein B-48 and B-100 (ApoB). Plasma samples were analysed with NTA before and after application of the bead procedure. Four fasting PFP samples were analysed with an ELISA specific for human ApoB to estimate the degree of removal of lipoproteins and EV array analysis was used for identification of possible EV loss.Results: The magnetic bead separation procedure resulted in a median reduction of the particle concentration in plasma by 62% (interquartile range 32–72%). The mean size of the remaining particles generally increased. ApoB concentration was reduced to a level close to the background signal, whereas a median reduction of the EV content by 21% (range 8–43%) was observed.Conclusion: Anti-ApoB antibody coated magnetic beads may hold potential for removal of lipoproteins from human PFP prior to EV measurement by NTA but some artefactual effect and EV loss may have to be endured.

Evaluation of the pharmacokinetic parameters of standard oral antibiotics in a bioequivalence study of generic products.

Pharmacokinetic parameters were summarized in clinical bioequivalence studies in Japan to confirm the validity for the use of parameters obtained from the clinical studies. Pharmacokinetic parameters, including maximum plasma/serum concentrations (Cmax), area under the plasma/serum drug concentration-time curve (AUC), time to achieve Cmax (Tmax), and half life (t1/2), of the standard products (original drugs) after oral administration of antimicrobials, including respiratory quinolones, cephalosporins, macrolides, and penicillin-based antibiotics were investigated by use of interview forms and/or package inserts from the generic products and the relationship among the pharmacokinetic parameters such as Cmax, AUC, Tmax, and t1/2 were estimated. In all the studies, the standard and generic products were administrated orally to healthy fasting subjects. Although there was more than a 1.5-fold difference in the Cmax and AUC0-24 h, but not in the Tmax and t1/2 values for levofloxacin tablets and cefacrol tablets, these parameters for other antibiotics were similar in various studies. The obtained results suggested that the parameters obtained from recent bioequivalence studies would be useful in identifying pharmacokinetic behavior of the original drugs, especially early time release; however, the pharmacokinetic results obtained from the recently conducted bioequivalence studies may be superior to those obtained from studies conducted in the past.

Pharmacokinetics of Paroxetine Tablets in healthy Arabic Subjects

A single oral dose of paroxetine 20 mg tablets (Seroxat®, GlaxoSmithKline, England) were administered to thirty six healthy male adult fasting subjects to study the pharmacokinetics of the drug in Arabic population.&#x0D; Twenty blood samples were obtained from each subject up to 96 hours after dosing. The concentrations of paroxetine were monitored in plasma to calculate the pharmacokinetic parameters; Cmax, Tmax, AUC0-t,AUC0-¥,Kel&amp; T0.5;applying non-compartmental analysis.&#x0D; The mean±SD for the abovementioned parameters were; 3.14±2.09 ng/ml, 5.1±1.28 hr, 48.6±45.9 ng.hr/ml, 59.5±42.3 ng.hr/ml, 0.066±0.022 hr-1 and 11.9±5.1 hrs, respectively. The present investigation demonstrated high inter individual variation particularly in the primary pharmacokinetic parameters Cmax (CV=66.5%), AUC0-t (CV=94.5%), and AUC0-¥ (CV=71%). Beside, comparing the results of the current investigation obtained from Arabic population with that published in other studies conducted in other nations indicating that there is clear population variability in the pharmacokinetic of paroxetine.&#x0D; Therefore, it can be concluded from the present investigation that individualization and therapeutic drug monitoring are suggested for optimal therapy with paroxetine. However, further investigations are recommended to confirm this suggestion by studying the pharmacokinetics of the drug in Arabic patients and after multiple dosing.

Effervescent N-Acetylcysteine Tablets versus Oral Solution N-Acetylcysteine in Fasting Healthy Adults: An Open-Label, Randomized, Single-Dose, Crossover, Relative Bioavailability Study

BackgroundOral solution N-acetylcysteine (NAC) is an antidote for acetaminophen overdose, but its unpleasant taste and aroma can impede delivery even after the coadministration of antiemetic medications. Flavored effervescent NAC tablets dissolved in water might be a more palatable formulation than oral solution NAC diluted with soft drink. ObjectivesTo evaluate the relative bioavailability of these 2 formulations and assess subjective preferences between them. MethodsThirty healthy adult volunteers (mean [SD] = 35.2 [9.14] years) were enrolled in this open-label, randomized, single-dose, crossover study, with a 7-day washout period. Volunteers were randomized to receive 11 g effervescent test formulation or the reference product under fasting conditions, after which 19 serial blood samples were collected over 48 hours. Total plasma NAC concentrations were evaluated by LC-MS, and pharmacokinetic parameters were calculated. The 2 formulations were considered bioequivalent if the 90% CIs of log-transformed ratios of pharmacokinetic parameters were within the predetermined bioequivalence range (80%–125%) established by the US Food and Drug Administration. Within 15 minutes of dosing, subjects were also asked to rank formulation attributes on a 5-point hedonic scale, with mean group differences analyzed by Wilcoxon signed rank test. Safety-profile assessment included treatment-emergent adverse events, physical examination, chemistry, and hematology parameters. ResultsThe concentration-versus-time profiles were similar for the 2 formulations, with mean Cmax of 26.5 μg/mL for effervescent NAC tablets and 28.4 μg/mL for oral solution NAC. The 90% CIs for the pharmacokinetic parameters met the criteria for concluding bioequivalence, and subjects preferred effervescent NAC tablets in terms of taste (P = 0.0247), flavor (P = 0.0082), texture (P = 0.009), and overall likeability (P = 0.0012), but there was no difference for smell (P = 0.0533). All treatment-emergent adverse events were mild, with no differences between the treatment groups. ConclusionsData from this study of a single dose of 11 g oral NAC demonstrated that effervescent NAC tablets and oral solution NAC met the regulatory criteria for bioequivalence in fasting healthy adult subjects. Effervescent NAC tablets appear to be a more palatable alternative for treatment of acetaminophen overdose. ClinicalTrials.gov identifier: NCT02723669.

Effects of blood glucose levels on resting-state EEG and attention in healthy volunteers.

Although glucose is the primary source of energy for the human brain, only a few studies have quantitatively evaluated the effects of glucose supply in healthy fasting subjects. Thus, this study used an EEG power spectral analysis to investigate whether alterations in EEG are associated with changes in blood glucose levels in healthy fasting subjects. This study included 24 healthy volunteers who underwent resting-state EEG and completed two attention examinations following a fasting period of at least 8 hours. The same tests were repeated after the participants ingested a glucose-rich drink. After consumption of the glucose-rich drink, significant increases in low alpha (8-10 Hz) and theta (4-8 Hz) power were observed in the whole brain and were especially prominent in the frontal and parieto-occipital regions. The participants performed better on the attention tests after than before the intake of glucose, but regional EEG changes were not correlated with this attentional enhancement. The present study demonstrated that recovery from low levels of blood glucose following a prolonged fasting period was associated with increased power in the theta and low alpha bands on a resting-state EEG and that this recovery was accompanied by improved attentional performance.

Platelet Aggregation Increased by Advanced Glycated Hemoglobin

Introduction: Many studies have provided strong evidence for an association between diabetes complications and an increase in platelet (PLT) reactivity. Though some metabolic abnormalities have been reported as the major causes of this reactivity and malfunction, the precise mechanism has not been fully elucidated. Aim: The aim of this study is to investigate the effect of advanced glycation end product of hemoglubin (AGE-Hb) on human PLT reactivity and malfunction. Materials and Methods: A solution of bovine hemoglobin was prepared with fructose in phosphate buffer. The solution was then sterilized and incubated under sterile conditions at 37°C in the dark. The control solution was prepared in the same way, but without fructose. Human PLTs were isolated and prepared from 15 healthy volunteers, men and women. Blood was collected in the morning from fasting healthy subjects using a 21-gauge needle with 117 mM sodium citrate (1:9 v/v), as an anticoagulant. Fluorescence measurements were performed using a Hitachi F-4500 spectrofluorometer. PLT aggregation was measured using the photometric system Packs-4 aggregometer. Results: The relative fluorescence intensity increased in Hb samples but not in controls that incubated with fructose. PLTS aggregation did not change in controls while after incubation with 10, 22, 30-days fructose-glycated Hb decreased by 10, 12, 30%, respectively. Taken together our data show that PLT secondary phase of ADP-induced aggregation gradually affected with advanced increase in Hb glycation.

Pharmacokinetics of caffeine and its metabolites in plasma and urine after consuming a soluble green/roasted coffee blend by healthy subjects

Coffee is widely consumed worldwide; therefore, the methylxanthines contained in coffee, mainly caffeine (CF), are among the most abundant bioactive compounds in our diet. In the present work, the bioavailability and metabolism of methylxanthines in a commercial soluble green/roasted coffee blend was studied. After a 3-day restriction of methylxanthine-containing foods, fasting healthy subjects (12 men and women) consumed the coffee product containing 70.69mg CF and 0.119mg theobromine (TB). Plasma samples were taken before (t=0h) and after coffee consumption at different time points (0.5, 1, 1.5, 2, 3, 4, 5, 6, 8, 9, 10 and 12h). Urine was collected at baseline (−2–0h) and at different intervals (0–2, 2–5, 5–8, 8–12 and 12–24h). Samples were analyzed by HPLC-DAD and LC–MS-QToF, and pharmacokinetic parameters were calculated. CF was the main methylxanthine found in plasma (Cmax=10.50μM, Tmax=1.2h). In addition, seven methylxanthines and methyluric acids were detected between 0.5 and 12h after coffee intake, paraxanthine (PX) being the major metabolite (Cmax=3.36μM), followed by 1-methyluric acid (1-MU; Cmax=1.44μM) and 1-methylxanthine (1-MX; Cmax=1.27μM), identified in plasma samples for the first time. In 24h urine, eleven methylxanthines and methyluric acids were detected, 1-MU being the major metabolite (Cmax=150.52μM, Tmax=12h) amounting to 67.7% of the total urinary metabolites. In conclusion, a rapid absorption, metabolization and excretion of caffeine and its derived methylxanthines and methyluric acids have been observed after consumption of a green/roasted coffee product.

Serum cholesterol and triglyceride reference ranges of twenty lipoprotein subclasses for healthy Japanese men and women

AimThis epidemiological study was done to generate normal ranges for the cholesterol and triglyceride levels in serum lipoprotein subclasses isolated from healthy adults based on gender and menopausal status. MethodsCholesterol and triglyceride levels in 20 lipoprotein subclasses as separated by high performance liquid chromatography were measured in serum obtained from 825 fasting healthy subjects (267 men, 558 women). ResultsFor serum cholesterol, 13.7% was found in very low density lipoprotein (VLDL) subclasses, 55.6% in low density lipoprotein (LDL) subclasses, and 30.4% in high density lipoprotein (HDL) subclasses. For serum triglycerides, these values were 52.1%, 27.9%, and 17.4%, respectively. Levels of cholesterol in some VLDL subclasses were inversely correlated with the levels of some HDL subclasses, while for triglycerides, elevated levels in any one subclass were generally strongly associated with elevated levels in all other subclasses. Men had significantly higher large VLDL-cholesterol levels than women (P < 0.05), while women had significantly higher small VLDL-cholesterol levels than men (P < 0.001). Women had significantly higher large LDL- and large and medium HDL-cholesterol levels than men (P < 0.001). Men had significantly higher chylomicron (CM), large and medium VLDL-, and small LDL-triglyceride levels than women (P < 0.001). Women had significantly higher very large and large HDL-triglyceride levels than men (P < 0.01). Postmenopausal women had significantly higher CM, all VLDL, and large, medium and small LDL-cholesterol levels, and significantly higher all VLDL, LDL, and HDL-triglyceride levels than premenopausal women (P < 0.001). ConclusionsOur data document important gender and menopausal status differences in cholesterol and triglyceride subclass levels, as well as significant correlations between values in the various serum lipoprotein subclasses.

Comment on Minamimoto: incidental focal FDG uptake in heart is a lighthouse for considering cardiac screening

Dear Sir,An interesting article has recently been published [1] on theclinical significance of focal cardiac FDG uptake inpatients with unknown cardiac disease studied for unre-lated purposes. The topic is of great interest because thepossibility to identify unexpected cardiac disease duringPET studies could allow an early diagnosis and reduceunfavorable events. The paper suggests a correlationbetween focal cardiac FDG uptake and the likelihood ofcoronary artery disease (CAD) in patients without cardiacsymptoms and unknown cardiac disease. Apart from theinteresting analysis and the effort to identify the clinicalsignificance of focal uptakes, we agree and highlight theremarks and concerns reported by the authors in the paper.The myocardium derives energy from many sources suchas free fatty acid (FFAs), glucose, pyruvate, ketone bodies,lactate, and amino acids [2–4]. In fasting and resting con-dition, heart metabolism is mainly based on FFAs oxida-tion, the myocardial FDG uptake should be negligible,glycolysis contributes only about 30 % of substrate butdietary and hormonal conditions can modify this situation[5]. In the fasting state, the rate of myocardial FFAs oxi-dation is high, inhibiting glycolysis and glucose oxidationwith consequently low levels of glucose and insulin, while,after glucose load or during hyperglycemic condition,plasma concentrations of glucose and insulin rise reducingperipheral lipolysis, lowering plasma concentrations ofFFAs and hence reducing their availability to the myo-cardium. Glucose then becomes the dominant substrate formyocardial energy production [5, 6]. However, the myo-cardial FDG uptake in the fasting healthy subjects variesunder the clinical fasting conditions [7, 8] and increasedFDG uptake in the myocardium does not significantlycorrelate with the blood glucose level, age, or duration offasting in non-diabetic patients [7, 9]. Only in the uncon-trolled diabetic patients with high levels of blood glucosethere is absent or faint myocardial FDG uptake. Myocardialischemia strikingly alters myocardial substrate metabolism[5]. As blood flow and oxygen supply decline, oxidativemetabolism decreases but still remains the dominant sourceof residual ATP production accounting for more than 90 %[10]. Ischemia is also associated with increased glycolysisbut becomes uncoupled from glucose oxidation with excessproduction of pyruvate and lactate which impair glycolysis[4, 11]. In the normal myocardium FDG distribution pat-terns could be classified into three types (absent to faintuptake; regional uptake; diffuse uptake), but they couldhave no specific meaning [7]. Moreover, even in the sameindividual and under similar fasting conditions, the myo-cardial FDG uptake is neither stable nor reproducible andthe transition from the intense FDG uptake of a dominantlyglycolytic myocardial metabolism to the absent FDGuptake of a dominantly FFAs metabolism is not entirelyuniform either temporally or regionally [6]. In daily clini-cal practise, despite adequate fasting period, the pattern ofmyocardial FDG heart uptake varies a lot, making difficultthe differential diagnosis between physiological and path-ological uptakes. For these reasons the results of

Does Ramadan Fasting Alter Body Weight and Blood Lipids and Fasting Blood Glucose in a Healthy Population? A Meta-analysis

In this study, we conducted a meta-analysis of self-controlled cohort studies comparing body weights, blood levels of lipids and fasting blood glucose levels before and after Ramadan taking into account gender differences. Several databases were searched up to June 2012 for studies showing an effect of Ramadan fasting in healthy subjects, yielding 30 articles. The primary finding of this meta-analysis was that after Ramadan fasting, low-density lipoprotein (SMD = -1.67, 95 % CI = -2.48 to -0.86) and fasting blood glucose levels (SMD = -1.10, 95 % CI = -1.62 to -0.58) were decreased in both sex groups and also in the entire group compared to levels prior to Ramadan. In addition, in the female subgroup, body weight (SMD = -0.04, 95 % CI = -0.20, 0.12), total cholesterol (SMD = 0.05, 95 % CI = -0.51 to 0.60), and triglyceride levels (SMD = 0.03, 95 % CI = -0.31, 0.36) remained unchanged, while HDL levels (SMD = 0.86, 95 % CI = 0.11 to 1.61, p = 0.03) were increased. In males, Ramadan fasting resulted in weight loss (SMD = -0.24, 95 % CI = -0.36, -0.12, p = 0.001). Also, a substantial reduction in total cholesterol (SMD = -0.44, 95 % CI = -0.77 to -0.11) and LDL levels (SMD = -2.22, 95 % CI = -3.47 to -0.96) and a small decrease in triglyceride levels (SMD = -0.35, 95 % CI = -0.67 to -0.02) were observed in males. In conclusion, by looking at this data, it is evident that Ramadan fasting can effectively change body weight and some biochemical parameters in healthy subjects especially in males compared to pre-Ramadan period.