Criticality of Surface Characteristics of Intravenous Iron-Carbohydrate Nanoparticle Complexes: Implications for Pharmacokinetics and Pharmacodynamics.

Un-complexed polynuclear ferric oxyhydroxide cannot be administered safely or effectively to patients. When polynuclear iron cores are formed with carbohydrates of various structures, stable complexes with surface carbohydrates driven by multiple interacting sites and forces are formed. These complexes deliver iron in a usable form to the body while avoiding the serious adverse effects of un-complexed forms of iron, such as polynuclear ferric oxyhydroxide. The rate and extent of plasma clearance and tissue biodistribution is variable among the commercially available iron-carbohydrate complexes and is driven principally by the surface characteristics of the complexes which dictate macrophage opsonization. The surface chemistry differences between the iron-carbohydrate complexes results in significant differences in in vivo pharmacokinetic and pharmacodynamic profiles as well as adverse event profiles, demonstrating that the entire iron-carbohydrate complex furnishes the pharmacologic action for these complex products. Currently available physicochemical characterization methods have limitations in biorelevant matrices resulting in challenges in defining critical quality attributes for surface characteristics for this class of complex nanomedicines.

Normal gastric emptying time of a carbohydrate-rich drink in elderly patients with acute hip fracture: a pilot study.

BACKGROUND: Guidelines for fasting in elderly patients with acute hip fracture are the same as for other trauma patients, and longer than for elective patients. The reason is assumed stress-induced delayed gastric emptying with possible risk of pulmonary aspiration. Prolonged fasting in elderly patients may have serious negative metabolic consequences. The aim of our study was to investigate whether the preoperative gastric emptying was delayed in elderly women scheduled for surgery due to acute hip fracture. METHODS: In a prospective study gastric emptying of 400 ml 12.6% carbohydrate rich drink was investigated in nine elderly women, age 77-97, with acute hip fracture. The emptying time was assessed by the paracetamol absorption technique, and lag phase and gastric half-emptying time was compared with two gender-matched reference groups: ten elective hip replacement patients, age 45-71 and ten healthy volunteers, age 28-55. RESULTS: The mean gastric half-emptying time in the elderly study group was 53 ± 5 (39-82) minutes with an expected gastric emptying profile. The reference groups had a mean half-emptying time of 58 ± 4 (41-106) and 59 ± 5 (33-72) minutes, indicating normal gastric emptying time in elderly with hip fracture. CONCLUSION: This pilot study in women with an acute hip fracture shows no evidence of delayed gastric emptying after an orally taken carbohydrate-rich beverage during the pre-operative fasting period. This implies no increased risk of pulmonary aspiration in these patients. Therefore, we advocate oral pre-operative management with carbohydrate-rich beverage in order to mitigate fasting-induced additive stress in the elderly with hip fracture. TRIAL REGISTRATION: ClinicalTrials.gov NCT02753010 . Registered 17 April 2016, retrospectively.

The intestinal glucose-apelin cycle controls carbohydrate absorption in mice.

BACKGROUND & AIMS: Glucose is absorbed into intestine cells via the sodium glucose transporter 1 (SGLT-1) and glucose transporter 2 (GLUT2); various peptides and hormones control this process. Apelin is a peptide that regulates glucose homeostasis and is produced by proximal digestive cells; we studied whether glucose modulates apelin secretion by enterocytes and the effects of apelin on intestinal glucose absorption. METHODS: We characterized glucose-related luminal apelin secretion in vivo and ex vivo by mass spectroscopy and immunologic techniques. The effects of apelin on (14)C-labeled glucose transport were determined in jejunal loops and in mice following apelin gavage. We determined levels of GLUT2 and SGLT-1 proteins and phosphorylation of AMPKα2 by immunoblotting. The net effect of apelin on intestinal glucose transepithelial transport was determined in mice. RESULTS: Glucose stimulated luminal secretion of the pyroglutaminated apelin-13 isoform ([Pyr-1]-apelin-13) in the small intestine of mice. Apelin increased specific glucose flux through the gastric epithelial barrier in jejunal loops and in vivo following oral glucose administration. Conversely, pharmacologic apelin blockade in the intestine reduced the increased glycemia that occurs following oral glucose administration. Apelin activity was associated with phosphorylation of AMPKα2 and a rapid increase of the GLUT2/SGLT-1 protein ratio in the brush border membrane. CONCLUSIONS: Glucose amplifies its own transport from the intestinal lumen to the bloodstream by increasing luminal apelin secretion. In the lumen, active apelin regulates carbohydrate flux through enterocytes by promoting AMPKα2 phosphorylation and modifying the ratio of SGLT-1:GLUT2. The glucose-apelin cycle might be pharmacologically handled to regulate glucose absorption and assess better control of glucose homeostasis.

Differential trafficking of saccharidic probes following aspirin in clinical tests of intestinal permeability in young healthy women.

The effects of inflammatory changes on the absorption of different-sized probes and their permeability ratios are poorly understood. The aim of the present study was to determine the effects of a pharmacological agent on the permeability of the gut mucosa to saccharidic probes of larger and smaller molecular weight. Permeability was assessed by half-hourly urinary excretion of a combined dose of d-mannitol, l-rhamnose and lactulose following consumption of a single 600 mg dose of aspirin and compared with a placebo in a cross-over study in 20 healthy female volunteers. The temporal patterns of excretion of all probes were bimodal, being best fitted by polynomial functions. The relatively small early peak was evident for at least 4 h for smaller sugars, but was less evident with lactulose, being overshadowed by a larger second peak. These conclusions were further supported by separate analyses of the segments of the temporal plots between 2.5 and 4 h and between 4.5 and 6 h. The forms of these curves did not change significantly following dosing with aspirin. A greater proportion of the total dose of mannitol than rhamnose was excreted over the collection period. Following the consumption of aspirin, the cumulative rate of excretion of the smaller sugars (i.e. mannitol and rhamnose) was significantly reduced whereas that of lactulose was increased over the 6 h collection period. Aspirin has opposite effects on the absorption of larger and smaller probes, influencing the outcome of the test. These results have important consequences for the design and comparison of clinical tests of permeability.

Amoeboid organism solves complex nutritional challenges.

A fundamental question in nutritional biology is how distributed systems maintain an optimal supply of multiple nutrients essential for life and reproduction. In the case of animals, the nutritional requirements of the cells within the body are coordinated by the brain in neural and chemical dialogue with sensory systems and peripheral organs. At the level of an insect society, the requirements for the entire colony are met by the foraging efforts of a minority of workers responding to cues emanating from the brood. Both examples involve components specialized to deal with nutrient supply and demand (brains and peripheral organs, foragers and brood). However, some of the most species-rich, largest, and ecologically significant heterotrophic organisms on earth, such as the vast mycelial networks of fungi, comprise distributed networks without specialized centers: How do these organisms coordinate the search for multiple nutrients? We address this question in the acellular slime mold Physarum polycephalum and show that this extraordinary organism can make complex nutritional decisions, despite lacking a coordination center and comprising only a single vast multinucleate cell. We show that a single slime mold is able to grow to contact patches of different nutrient quality in the precise proportions necessary to compose an optimal diet. That such organisms have the capacity to maintain the balance of carbon- and nitrogen-based nutrients by selective foraging has considerable implications not only for our understanding of nutrient balancing in distributed systems but for the functional ecology of soils, nutrient cycling, and carbon sequestration.

Self-assembled carbohydrate hydrogels for prolonged pain management.

CONTEXT: Nanoparticulate systems are new tools that promise a revolution in the field of drug delivery. Among their numerous benefits, polyelectrolyte complexes (PECs) have shown to provide a barrier to drug release. OBJECTIVE: In this study, PECs, in the form of self-assembled polymeric nanogels, have been studied as potential drug carriers of the freely soluble drug tramadol HCL trying to achieve a prolonged percutaneous permeation. METHODOLOGY: The hydrogels were subjected to swelling, rheology, release and permeation studies and were characterized by FTIR spectroscopy and scanning electron microscopy. RESULTS: P2 hydrogel composed of chitosan-carrageenan (1-1) PEC attained the most compromised rheological shear-thinning thixotropic behavior, good bioadhesive properties, the most retarded release and permeation with an f2 value <50 compared to chitosan hydrogel, altogether with non-irritancy to the skin. SEM photographs showed that P2 has spherical nanosized particles structure. CONCLUSION: This approach can provide us promising results for an around-the-clock analgesia with better safety and tolerability profile.

Enzymatic methods for glyco(diversification/randomization) of drugs and small molecules.

Glyco (randomization/diversification) is a term that encompasses strategies to diversify a core drug scaffold via enzymatic glycosylation to provide sets of analogs wherein the sole diversity element is a carbohydrate. This review covers the influence of glycosylation upon various drug properties, the classes of glycosyl-conjugating enzymes amenable to glyco(randomization/diversification) schemes, approaches to the synthesis of required substrates and specific examples of glycorandomized libraries utilizing both wild-type and engineered enzymes.

Processing of four different cooking methods of Oudemansiella radicata: Effects on in vitro bioaccessibility of nutrients and antioxidant activity.

The purpose of this study is to evaluate the bioaccessibility of nutrients and antioxidant activity of O. radicata after subjecting to four types of domestic cooking and followed by in vitro digestion. The result demonstrated that the group with the lowest amino acid release and the degree of protein hydrolysis (5.6%) was frying, but both reducing sugar content and antioxidant activity were the highest. The composition of fatty acids was different than undigested samples, especially the relative content of linolenic acid was significantly decreased (e.g., 34.49 to 8.23%, boiled). The difference of the minerals bioaccessibility was slightly affected by the cooking method, but mainly related to their natural properties, such as the highest phosphorus (62.73%) and the lowest iron (21.53%) in the steaming. The above data provides a starting point for the design of processes at an industrial and gastronomic level.

Carbohydrate based biomarkers enable hybrid near infrared fluorescence and 64Cu based radio-guidance for improved surgical precision.

Increasing numbers of lung tumors are identified at early disease stages by diagnostic imaging in screening programs, but difficulties in locating these during surgical intervention has prevented an improved treatment outcome. Surgical biomarkers that are visible on diagnostic images, and that provide the surgeon with real-time image guidance during the intervention are thus highly warranted to bridge diagnostic precision into enhanced therapeutic outcome. In this paper, a liquid soft tissue marker for near infrared fluorescence and radio-guidance is presented. The biocompatible marker is based on the carbohydrate ester, sucrose acetate isobutyrate, ethanol, and a multifunctional naphthalocyanine dye, which enable near infrared fluorescence image-guided resection at short, medium and long tissue depths. Naphthalocyanine dyes have high quantum yields and may further act as chelators of radionuclides. Upon injection of the liquid marker, a gel-like depot is formed in situ at the site of injection, wherein the fluorescent dye and radionuclide is retained. The radiolabeled markers were optimized for minimal fluorescence quenching and high retention of the positron emission tomography radionuclide 64Cu. The performance of the radiolabeled marker was tested in vivo in mice, where it displayed high photostability over a period of 4 weeks, and high retention of 64Cu for 48 hours. The retention and biodistribution of 64Cu was quantified via PET/CT, and the fluorescence emission by an in vivo imaging system. The presented data demonstrate proof-of-concept for naphthalocyanine markers as multimodal imaging agents that can bridge the precision of diagnostic imaging into surgical interventions.

Synthesis and biodistribution studies of carbohydrate derivatives radiolabeled with technetium-99m.

Three carbohydrate derivatives, MAG(3)-Gl, MAG(3)-Ga, MAG(3)-NG, were synthesized and radiolabeled in high yields. These substances were injected in health Swiss mice and their biodistribution were evaluated. Among them, (99m)Tc-MAG(3)-Ga displayed higher accumulation in hepatic tissue, due to the presence of specific receptors in the liver for this carbohydrate. Thus, the use of (99m)Tc-MAG(3)-Ga to assess hepatic function can be considered.

Combinatorics of feedback in cellular uptake and metabolism of small molecules.

We analyze the connection between structure and function for regulatory motifs associated with cellular uptake and usage of small molecules. Based on the boolean logic of the feedback we suggest four classes: the socialist, consumer, fashion, and collector motifs. We find that the socialist motif is good for homeostasis of a useful but potentially poisonous molecule, whereas the consumer motif is optimal for nutrition molecules. Accordingly, examples of these motifs are found in, respectively, the iron homeostasis system in various organisms and in the uptake of sugar molecules in bacteria. The remaining two motifs have no obvious analogs in small molecule regulation, but we illustrate their behavior using analogies to fashion and obesity. These extreme motifs could inspire construction of synthetic systems that exhibit bistable, history-dependent states, and homeostasis of flux (rather than concentration).

Fermentation kinetics and chemical characterisation of vino tostado, a traditional sweet wine from Galicia (NW Spain).

BACKGROUND: Grapes after harvesting are air dried and pressed in order to concentrate sugars, acids and flavour compounds to produce vino tostado (toasted wine), a wine with intense aroma and flavour notes and high residual sugar concentration. In order to get a better knowledge of the difficulties involved, several fermentations were conducted at 12 and 28 degrees C using 0, 15 and 30 g hL(-1) ammonium sulfate and 0, 25 and 50 g hL(-1) exogenous commercial yeast (Saccharomyces cerevisiae var. bayanus) to study the kinetics of sugar consumption and ethanol, acetic acid and glycerol production. RESULTS: Fermentation kinetic parameters were calculated and metal concentrations and antioxidant activity were analysed. CONCLUSION: The spontaneous fermentation at 12 degrees C and all fermentations conducted with the commercial yeast gave vino tostado of adequate quality, while the spontaneous fermentation at 28 degrees C was sluggish. High-temperature fermentations led to sweeter wines with higher volumetric productivities, although low-temperature fermentations produced better wines in terms of higher glycerol and lower acetic acid levels. Fructose was the only sugar to be consumed during spontaneous fermentations, while both glucose and fructose were consumed during fermentations of the inoculated musts, with preference for each monosaccharide depending on temperature.

Citrulline as a marker for chemotherapy induced mucosal barrier injury in pediatric patients.

BACKGROUND: The currently used National Cancer Institute (NCI) adverse events criteria for mucosal barrier injury (MBI) are insufficient for use in children. We searched for objective, easily measurable indicators for MBI in children with cancer. PURPOSE: In children with acute myeloid leukemia, various MBI-related clinical and laboratory tests were investigated, reflecting clinical severity (NCI symptomatic adverse events criteria (gold standard), daily gut score (DGS)), inflammation (plasma and fecal interleukin-8 (IL-8), fecal calprotectin), enterocytic loss (plasma citrulline, ratio fecal human DNA/total DNA) and intestinal permeability (sugar absorption tests). RESULTS: Intestinal MBI as detected by the NCI adverse events criteria was found in 55% of chemotherapy cycles, correlating well with the continuous DGS (n = 55, rho = 0.581; P < 0.001). Intestinal cell loss as measured by the ratio fecal human DNA/total DNA and plasma citrulline correlated well with both NCI criteria (n = 61, rho = 0.357, P = 0.005 resp. n = 58, rho = -0.482; P < 0.001) and DGS (n = 54, rho = 0.352, P = 0.009 resp. n = 55, rho = -0.625; P < 0.001). Plasma IL-8 correlated strongly to plasma citrulline (n = 46, rho = -0.627; P < 0.001). CONCLUSIONS: MBI was reflected by parameters indicating inflammation (IL-8) and cell loss (plasma citrulline, ratio fecal human DNA/total DNA). We conclude that plasma citrulline might be a good parameter for MBI. Further studies are needed to show whether plasma citrulline can be used as a marker for MBI in future research.

Current strategies in extending half-lives of therapeutic proteins.

Macromolecular protein and peptide therapeutics have been proven to be effective in treating critical human diseases precisely. Thanks to biotechnological advancement, a huge number of proteins and peptide therapeutics were made their way to pharmaceutical market in past few decades. However, one of the biggest challenges to be addressed for protein therapeutics during clinical application is their fast degradation in serum and quick elimination owing to enzymatic degradation, renal clearance, liver metabolism and immunogenicity, attributing to the short half-lives. Size and hydrophobicity of protein molecules make them prone to kidney filtration and liver metabolism. On the other hand, proteasomes responsible for protein destruction possess the capability of specifically recognizing almost all kinds of foreign proteins while avoiding any unwanted destruction of cellular components. At present almost all protein-based drug formulations available in market are administered intravenously (IV) or subcutaneously (SC) with high dosing at frequent interval, eventually creating dose-fluctuation-related complications and reducing patient compliance vastly. Therefore, artificially increasing the therapeutic half-life of a protein by attaching to it a molecule that increases the overall size (eg, PEG) or helps with receptor mediated recycling (eg, albumin), or manipulating amino acid chain in a way that makes it more prone towards aggregate formation, are some of the revolutionary approaches to avoid the fast degradation in vivo. Half-life extension technologies that are capable of dramatically enhancing half-lives of proteins in circulation (2-100 folds) and thus improving their overall pharmacokinetic (PK) parameters have been successfully applied on a wide range of protein therapeutics from hormones and enzymes, growth factor, clotting factor to interferon. The focus of the review is to assess the technological advancements made so far in enhancing circulatory half-lives and improving therapeutic potency of proteins.

The sugar porter gene family of Laccaria bicolor: function in ectomycorrhizal symbiosis and soil-growing hyphae.

Formation of ectomycorrhizas, a symbiosis with fine roots of woody plants, is one way for soil fungi to overcome carbohydrate limitation in forest ecosystems. Fifteen potential hexose transporter proteins, of which 10 group within three clusters, are encoded in the genome of the ectomycorrhizal model fungus Laccaria bicolor. For 14 of them, transcripts were detectable. When grown in liquid culture, carbon starvation resulted in at least twofold higher transcript abundances for seven genes. Temporarily elevated transcript abundance after sugar addition was observed for three genes. Compared with the extraradical mycelium, ectomycorrhiza formation resulted in a strongly enhanced expression of six genes, of which four revealed their highest observed transcript abundances in symbiosis. A function as hexose importer was proven for three of them. Only three genes, of which just one was expressed at a considerable level, revealed a reduced transcript content in mycorrhizas. From gene expression patterns and import kinetics, the L. bicolor hexose transporters could be divided into two groups: those responsible for uptake of carbohydrates by soil-growing hyphae, for improved carbon nutrition, and to reduce nutrient uptake competition by other soil microorganisms; and those responsible for efficient hexose uptake at the plant-fungus interface.

Design, synthesis, and radiosensitizing activities of sugar-hybrid hypoxic cell radiosensitizers.

We have designed sugar-hybrid TX-1877 derivatives conjugated with sugar moieties including beta-glucose (beta-Glc), beta-galactose (beta-Gal), alpha-mannose (alpha-Man) and N-acetyl-beta-galactosamine (beta-GalNAc). Compound 1 (TX-1877) was glycosylated with appropriate peracetylated sugars using BF(3)-OEt(2) to give acetylated sugar-hybrids, 5 (TX-2244), 6 (TX-2245), 7 (TX-2246), and 10 (TX-2243). Removal of the acetyl groups afforded the sugar-hybrids having free hydroxyl groups, 11 (TX-2141), 12 (TX-2218), 13 (TX-2217) and 14 (TX-2068). We evaluated their radiosensitizing activities by an in vitro radiosensitization assay. All free hydroxyl hybrids have lower enhancement ratio (ER) values (ER1.43) and lower n-octanol/water partition coefficient (P(oct)) values (P(oct)<1.00x10(-2)) than does 1 (TX-1877, ER=1.75, P(oct): 5.60x10(-2)). All acetylated hybrids have similar P(oct) values (3.55x10(-2)-1.05x10(-1)) to 1 (TX-1877) and have improved ER values (ER>or=1.47) compared to the hybrids having free hydroxyl groups. Among these, 5 (TX-2244) is the most active radiosensitizer (ER=2.30). We found a good correlation (r=0.866) between the magnitude of P(oct) (logP(oct)) and the ER value of 5 (TX-2244), 6 (TX-2245), 7 (TX-2246), 10 (TX-2243) and 1 (TX-1877), suggesting that increasing the hydrophobicity is reflected in increased in vitro radiosensitizing activity. In the present study, we have succeeded in producing sugar-hybrid hypoxic cell radiosensitizers that have an increased radiosensitizing activity that does not depend on increased hydrophobicity.

Mechanism of the inhibitory action of chestnut astringent skin extract on carbohydrate absorption.

Chestnut astringent skin (CAS) extract inhibited pancreatic alpha-amylase and intestinal alpha-glucosidase in a concentration-dependent manner with the 50% inhibition concentration (IC50) for amylase, maltase and sucrase being 7.5, 650 and 390 microg/mL, respectively. We have investigated the effect of CAS extract on carbohydrate absorption in normal rats. Oral administration of CAS extract to rats fed cornstarch (2 g/kg body weight) significantly suppressed the increase of blood glucose levels and the area under the curve (AUC). Administration of CAS extract to rats fed maltose or sucrose delayed the increase of blood glucose level and slightly suppressed AUC, but not significantly. Administration of CAS extract to rats fed glucose did not affect the increase in blood glucose level or AUC. Similar results were observed with type-2 diabetic model rats (GK/jcl). To test the effect of CAS extract on diabetes, type 2 diabetic model mice (db/db mice) were fed a standard laboratory diet containing 1 or 2% CAS extract. CAS extract prevented increases in body weight and fasting blood glucose concentration. These data suggest that CAS extract has an anti-diabetic function in type 2 diabetic mice that mainly functions through inhibition of alpha-amylase.

Feeding a slowly digestible carbohydrate diet during pregnancy of insulin-resistant rats prevents the excess of adipogenesis in their offspring.

An obesogenic environment during pregnancy has been shown to increase the risk of dysregulation on adipogenesis and insulin resistance in the offspring. Being essential for the growing fetus, glucose supply is guaranteed by a number of modifications in the mother's metabolism, and thus, glucose control during pregnancy especially among obese or diabetic women is paramount to prevent adverse consequences in their children. Besides the election of low-glycemic-index carbohydrates, the rate of carbohydrate digestion could be relevant to keep a good glucose control. In the present study, we compared the effects of two high-fat diets with similar glycemic load but different rates of carbohydrate digestion given to pregnant insulin-resistant rats. After birth, all animals were fed a standard diet until age 14 weeks. We analyzed offspring body composition, plasma and adipocyte lipidomics, lipid metabolism in adipose tissue and insulin sensitivity. Those animals whose mothers were fed the rapid-digesting carbohydrate diet exhibited an excessive adipogenesis. Thus, these animals showed a marked lipidemia, increased lipid synthesis in the adipose tissue and reduced glucose transporter amount in the adipose. On the contrary, those animals whose mothers were fed the slow-digesting carbohydrate diet showed a profile in the measured parameters closer to that of the offspring of healthy mothers. These results support the hypothesis that not only glycemic index but the rate of carbohydrate digestion during gestation may be critical to regulate the programming of adipogenesis in the offspring.