Iron Measured in Nasal Exudate Samples as a New and Useful Biomarker in the Differential Diagnosis of Patients with Acute Stroke.

INTRODUCTION: Differential diagnosis between ischemic and hemorrhagic strokes in the acute stage is one of the major challenges of neurovascular research. Several biomarkers have been studied, but attempts to date have focused on determining their blood levels. Recently, cerebral lymphatic drainage toward the nostrils has been discovered, giving us the chance to study nasal exudate looking for biomarkers of neural damage. We sought to confirm whether iron levels in nasal exudate could identify the hemorrhagic nature of acute stroke. METHODS: We studied iron nasal exudate levels in 32 ischemic and 43 hemorrhagic stroke patients. All patients underwent neurological examination assessed by the National Institutes of Health Stroke Scale (NIHSS), brain computed tomography to the differential diagnosis of stroke subtype, laboratory tests, and measurement of iron levels in nasal exudate. RESULTS: The iron levels in nasal exudate were higher in hemorrhagic stroke patients. The area under the receiver operating characteristic curve for ischemic/hemorrhagic stroke discrimination was 0.896 (95% confidence interval 0.823-0.970) and cutoff point of 0.078 nmol/mg (sensitivity 93%, specificity 73%). CONCLUSIONS: Our findings suggest that iron levels in nasal exudate may be useful in the acute stage for the differential diagnosis between ischemic and hemorrhagic damage in acute stroke patients. They also open a potential field to study other biomarkers in nasal exudate in several neurological disorders. Clinical studies must be performed to confirm our results.

Mesenteric Lymph Duct Drainage Attenuates Lung Inflammatory Injury and Inhibits Endothelial Cell Apoptosis in Septic Rats.

The present study was to investigate the effect of mesenteric lymph duct drainage on lung inflammatory response, histological alteration, and endothelial cell apoptosis in septic rats. Animals were randomly assigned into four groups: control, sham surgery, sepsis, and sepsis plus mesenteric lymph drainage. We used the colon ascendens stent peritonitis (CASP) procedure to induce the septic model in rats, and mesenteric lymph drainage was performed with a polyethylene (PE) catheter inserted into mesenteric lymphatic. The animals were sacrificed at the end of CASP in 6 h. The mRNA expression levels of inflammatory mediators were measured by qPCR, and the histologic damage were evaluated by the pathological score method. It was found that mesenteric lymph drainage significantly reduced the expression of TNF-α, IL-1ß, and IL-6 mRNA in the lung. Pulmonary interstitial edema and infiltration of inflammatory cells were alleviated by mesenteric lymph drainage. Moreover, increased mRNA levels of TNF-α, IL-1ß, IL-6 mRNA, and apoptotic rate were observed in PMVECs treated with septic lymph. These results indicate that mesenteric lymph duct drainage significantly attenuated lung inflammatory injury by decreasing the expression of pivotal inflammatory mediators and inhibiting endothelial apoptosis to preserve the pulmonary barrier function in septic rats.

Rapeseed Lecithin Increases Lymphatic Lipid Output and α-Linolenic Acid Bioavailability in Rats.

BACKGROUND: Soybean lecithin, a plant-based emulsifier widely used in food, is capable of modulating postprandial lipid metabolism. With arising concerns of sustainability, alternative sources of vegetal lecithin are urgently needed, and their metabolic effects must be characterized. OBJECTIVES: We evaluated the impact of increasing doses of rapeseed lecithin (RL), rich in essential α-linolenic acid (ALA), on postprandial lipid metabolism and ALA bioavailability in lymph-cannulated rats. METHODS: Male Wistar rats (8 weeks old) undergoing a mesenteric lymph duct cannulation were intragastrically administered 1 g of an oil mixture containing 4% ALA and 0, 1, 3, 10, or 30% RL (5 groups). Lymph fractions were collected for 6 h. Lymph lipids and chylomicrons (CMs) were characterized. The expression of genes implicated in intestinal lipid metabolism was determined in the duodenum at 6 h. Data was analyzed using either sigmoidal or linear mixed-effects models, or one-way ANOVA, where appropriate. RESULTS: RL dose-dependently increased the lymphatic recovery (AUC) of total lipids (1100 µg/mL·h per additional RL%; P = 0.010) and ALA (50 µg/mL·h per additional RL%; P = 0.0076). RL induced a faster appearance of ALA in lymph, as evidenced by the exponential decrease of the rate of appearance of ALA with RL (R2 = 0.26; P = 0.0064). Although the number of CMs was unaffected by RL, CM diameter was increased in the 30%-RL group, compared to the control group (0% RL), by 86% at 3-4 h (P = 0.065) and by 81% at 4-6 h (P = 0.0002) following administration. This increase was positively correlated with the duodenal mRNA expression of microsomal triglyceride transfer protein (Mttp; ρ= 0.63; P = 0.0052). The expression of Mttp and secretion-associated, ras-related GTPase 1 gene homolog B (Sar1b, CM secretion), carnitine palmitoyltransferase IA (Cpt1a) and acyl-coenzyme A oxidase 1 (Acox1, beta-oxidation), and fatty acid desaturase 2 (Fads2, bioconversion of ALA into long-chain n-3 PUFAs) were, respectively, 49%, 29%, 74%, 48%, and 55% higher in the 30%-RL group vs. the control group (P < 0.05). CONCLUSIONS: In rats, RL enhanced lymphatic lipid output, as well as the rate of appearance of ALA, which may promote its subsequent bioavailability and metabolic fate.

Cytokines of the Lymph and Blood Serum as Markers of Oncogenesis and Efficiency of Therapy in Chemically Induced Breast Cancer in Wistar Rats.

We studied the levels of serum and lymph cytokines involved in the pathogenesis of BC. BC was induced by injection of N-methyl-N-nitrosourea to Wistar rats. The animals underwent surgery, or received polychemotherapy (cyclophosphamide, methotrexate, and 5-fluorouracil), or surgical treatment was combined with polychemotherapy; in a special group, Panagen (fragmented DNA) was added to polychemotherapy. Cytokine concentration in the lymph was measured using Bio-Plex Pro Rat Cytokoness 24-Plex Assay test system (Bio-Rad). In rats with BC, the content of most studied cytokines (IL-1ß, IL-2, IL-4, IL-6, IL-7, IL-12, IL-13, MIP-1α, MIP-3α, RANTES, TNFα, and MCP-1) in the lymph and blood was significantly higher, while the content of IL-10 and GRO/KC was lower than in intact animals. Surgical resection of the tumor led to a significant decrease in the content of both pro- and anti-inflammatory cytokines in the lymph. Polychemotherapy led to a significant decrease in the content of IL-1ß, IL-4, IL-6, IL-7, MIP-1α, MIP-3α, and RANTES in the serum and lymph. Comparison of the cytokine content in the serum and lymph of operated animals after polychemotherapy with and without Panagen showed that the content of most cytokines (IL-5, IL-6, IL-7, IL-10, IL-13, IL-17A , IL-18, GRO/KC, IFNγ, and MIP-3α) was higher after Panagen administration.

Organ-specific lymphatics play distinct roles in regulating HDL trafficking and composition.

Recently, peripheral lymphatic vessels were found to transport high-density lipoprotein (HDL) from interstitial tissues to the blood circulation during reverse cholesterol transport. This function is thought to be critical to the clearance of cholesterol from atherosclerotic plaques. The role of organ-specific lymphatics in modulating HDL transport and composition is, however, incompletely understood. This study aimed to 1) determine the contribution of the lymphatics draining the intestine and liver (which are major sites of HDL synthesis) to total (thoracic) lymph HDL transport and 2) verify whether the HDLs in lymph are derived from specific organs and are modified during trafficking in lymph. The mesenteric, hepatic, or thoracic lymph duct was cannulated in nonfasted Sprague-Dawley rats, and lymph was collected over 5 h under anesthesia. Whole lymph and specific lymph lipoproteins (isolated by ultracentrifugation) were analyzed for protein and lipid composition. The majority of thoracic lymph fluid, protein, and lipid mass was sourced from the mesenteric, and to a lesser extent, hepatic lymph. Mesenteric and thoracic lymph were both rich in chylomicrons and very low-density lipoprotein, whereas hepatic lymph and plasma were HDL-rich. The protein and lipid mass in thoracic lymph HDL was mostly sourced from mesenteric lymph, whereas the cholesterol mass was equally sourced from mesenteric and hepatic lymph. HDLs were compositionally distinct across the lymph sources and plasma. The composition of HDL also appeared to be modified during passage from the mesenteric and hepatic to the thoracic lymph duct. Overall, this study demonstrates that the lipoproteins in lymph are organ specific in composition, and the intestine and liver appear to be the main source of HDL in the lymph.NEW & NOTEWORTHY High-density lipoprotein in lymph are organ-specific in composition and derive mostly from the intestine and liver. High-density lipoprotein also appears to be remodeled during transport through the lymphatics. These findings have implications to cardiometabolic diseases that involve perturbations in lipoprotein distribution and metabolism.

Intestinal bioavailability of n-3 long-chain polyunsaturated fatty acids influenced by the supramolecular form of phospholipids.

The aim of this work was to study the bioavailability of n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), i.e. eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), carried by marine phospholipids (PL) and formulated in different supramolecular forms. Marine PL were administrated in rats either (1) in bulk form, or (2) as an oil-in-water emulsion, or (3) as liposomes. Each dietary formulation was characterized by a similar fatty acid (FA) profile and provided the same n-3 LC-PUFA amount. Intestinal bioavailability of n-3 LC-PUFA was monitored in the lymph compartment in a duct fistula model. On the one hand, the emulsification of plant oils with PL increased the overall intestinal absorption of dietary FA by 84% without affecting the lymph FA profile compared with the bulk form, suggesting that emulsification favoured the absorption of the total dietary FA derived from both triglycerides (TG) and PL. On the other hand, the liposome form did not modify the lymph lipid amount compared with the bulk form, but specifically increased the n-3 LC-PUFA levels. The dietary forms of PL influenced the position of some FA on the glycerol backbone of lymph TG and PL. In conclusion, using marine PL as an emulsifier promoted total FA absorption independently of the dietary lipid carrier (TG or PL) and the FA type. Structuring PL as liposomes specifically increased the intestinal bioavailability of FA esterifed in this lipid class, such as DHA, resulting in a higher incorporation into lymph lipids. Thus, using specific PL supramolecular forms would guide n-3 LC-PUFA towards total lipid absorption or specific FA absorption, according to the dietary needs.

In Vitro Evaluation of the Polymerization Properties of N-Butyl Cyanoacrylate/Iodized Oil Mixtures for Lymphatic Interventions.

PURPOSE: To evaluate polymerization of N-butyl cyanoacrylate (NBCA)/iodized oil mixtures for lymphatic interventions in vitro. MATERIALS AND METHODS: Polymerization times of different NBCA/iodized oil mixtures (ratios of 1:0-1:7) were investigated in a static and dynamic experimental setup (performed in a lymph flow model in a silicone tube). Eight lymphatic samples with different triglyceride (TG) concentrations (low TGs, < 50 mg/dL; medium TGs, approximately 100-400 mg/dL; high TGs, > 700 mg/dL) were investigated. Morphologic changes during NBCA polymerization were monitored and recorded by video. Statistical analysis was performed with intergroup comparisons (Kruskal-Wallis test) and multiple regression analysis. RESULTS: Static experiments showed increasing polymerization times with increasing concentrations of iodized oil as well as increasing concentrations of TGs. In the low-TG group, polymerization time increased from 14 s at a 1:1 ratio of NBCA to iodized oil to 1,336 s at a 1:7 ratio; times in the medium-TG group increased from 21 s (1:1) to 2,546 s (1:7), and those in the high TG group increased from 168 s (1:1) to 16,530 s (1:7). In dynamic experiments, prolongation of polymerization time was less pronounced. For low- and medium-TG groups, total occlusion of the silicon tube was observed in all cases during the embolization procedure at between 26 seconds (1:1 ratio) and 52 seconds (1:7). In the high-TG group, polymerization took considerably longer (between 43 s [1:1] and 467 s [1:7]) or failed completely. CONCLUSIONS: Polymerization time of NBCA/iodized oil in lymph seems to be prolonged by increasing iodized oil and TG concentrations.

Quantitative Profiling of the Lymph Node Clearance Capacity.

Transport of tissue-derived lymphatic fluid and clearance by draining lymph nodes are pivotal for maintenance of fluid homeostasis in the body and for immune-surveillance of the self- and non-self-proteomes. Yet a quantitative analysis of nodal filtration of the tissue-derived proteome present in lymphatic fluid has not been reported. Here we quantified the efficiency of nodal clearance of the composite proteomic load using label-free and isotope-labeling proteomic analysis of pre-nodal and post-nodal samples collected by direct cannulation. These results were extended by quantitation of the filtration efficiency of fluorophore-labeled proteins, bacteria, and beads infused at physiological flow rates into pre-nodal lymphatic collectors and collected by post-nodal cannulation. We developed a linear model of nodal filtration efficiency dependent on pre-nodal protein concentrations and molecular weight, and uncovered criteria for disposing the proteome incoming from defined anatomical districts under physiological conditions. These findings are pivotal to understanding the maximal antigenic load sustainable by a draining node, and promote understanding of pathogen spreading and nodal filtration of tumor metastasis, potentially helping to improve design of vaccination protocols, immunization strategies and drug delivery.

Structure and Distribution of an Unrecognized Interstitium in Human Tissues.

Confocal laser endomicroscopy (pCLE) provides real-time histologic imaging of human tissues at a depth of 60-70 µm during endoscopy. pCLE of the extrahepatic bile duct after fluorescein injection demonstrated a reticular pattern within fluorescein-filled sinuses that had no known anatomical correlate. Freezing biopsy tissue before fixation preserved the anatomy of this structure, demonstrating that it is part of the submucosa and a previously unappreciated fluid-filled interstitial space, draining to lymph nodes and supported by a complex network of thick collagen bundles. These bundles are intermittently lined on one side by fibroblast-like cells that stain with endothelial markers and vimentin, although there is a highly unusual and extensive unlined interface between the matrix proteins of the bundles and the surrounding fluid. We observed similar structures in numerous tissues that are subject to intermittent or rhythmic compression, including the submucosae of the entire gastrointestinal tract and urinary bladder, the dermis, the peri-bronchial and peri-arterial soft tissues, and fascia. These anatomic structures may be important in cancer metastasis, edema, fibrosis, and mechanical functioning of many or all tissues and organs. In sum, we describe the anatomy and histology of a previously unrecognized, though widespread, macroscopic, fluid-filled space within and between tissues, a novel expansion and specification of the concept of the human interstitium.

Selective Absorption of Dietary Sphingoid Bases from the Intestine via Efflux by P-Glycoprotein in Rats.

Various physiological functions of dietary sphingolipids, such as preventing inflammation and improving the skin barrier function, have been recently demonstrated. The sphingolipid most commonly used as a foodstuff is glucosylceramide from plant sources, which is composed of sphingoid bases that are distinctive from those found in mammals. Although the structure of sphingoid bases in higher plants is more complicated than the structure of those in mammals, the fate of dietary sphingolipids of plant origin is still not understood. In the present study, we investigated the absorption of 4,8-sphingadienine that originated from maize glucosylceramide in the rat intestine by using a lipid absorption assay of lymph collected from the thoracic duct. The cumulative recovery of 4,8-sphingadienine in the lymph was lower than that of sphingosine. Verapamil, a P-glycoprotein inhibitor, significantly increased the absorption of 4,8-sphingadienine but did not affect the absorption of sphingosine. Plant-derived sphingoid bases were detected in the ceramide fraction of lymph fluid by using liquid chromatography-mass spectrometry analysis. These results indicate that 4,8-sphingadienine that originates from the glucosylceramide of higher plants is poorly absorbed in the intestine because of efflux by P-glycoprotein and can be incorporated into a ceramide moiety, at least in part, in intestinal endothelial cells.

Naturally occurring fluorescence in frogs.

Fluorescence, the absorption of short-wavelength electromagnetic radiation reemitted at longer wavelengths, has been suggested to play several biological roles in metazoans. This phenomenon is uncommon in tetrapods, being restricted mostly to parrots and marine turtles. We report fluorescence in amphibians, in the tree frog Hypsiboas punctatus, showing that fluorescence in living frogs is produced by a combination of lymph and glandular emission, with pigmentary cell filtering in the skin. The chemical origin of fluorescence was traced to a class of fluorescent compounds derived from dihydroisoquinolinone, here named hyloins. We show that fluorescence contributes 18-29% of the total emerging light under twilight and nocturnal scenarios, largely enhancing brightness of the individuals and matching the sensitivity of night vision in amphibians. These results introduce an unprecedented source of pigmentation in amphibians and highlight the potential relevance of fluorescence in visual perception in terrestrial environments.

Pinolenic Acid in Structured Triacylglycerols Exhibits Superior Intestinal Lymphatic Absorption As Compared to Pinolenic Acid in Natural Pine Nut Oil.

The positional distribution pattern of fatty acids (FAs) in the triacylglycerols (TAGs) affects intestinal absorption of these FAs. The aim of this study was to compare lymphatic absorption of pinolenic acid (PLA) present in structured pinolenic TAG (SPT) where PLA was evenly distributed on the glycerol backbone, with absorption of pine nut oil (PNO) where PLA was predominantly positioned at the sn-3 position. SPT was prepared via the nonspecific lipase-catalyzed esterification of glycerol with free FA obtained from PNO. Lymphatic absorption of PLA from PNO and from SPT was compared in a rat model of lymphatic cannulation. Significantly (P < 0.05) greater amounts of PLA were detected in lymph collected for 8 h from an emulsion containing SPT (28.5 ± 0.7% dose) than from an emulsion containing PNO (26.2 ± 0.6% dose), thereby indicating that PLA present in SPT has a greater capacity for lymphatic absorption than PLA from PNO.

Levels of miRNA and Hormones in Thoracic Duct Lymph in Rats with Experimental Breast Cancer Induced by N-Methyl-N-Nitrosourea.

We studied hormone levels in the thoracic duct lymph and expression of miRNA involved in the pathogenesis of breast cancer induced in rats by intramammary injection of N-methyl-Nnitrosourea. The correlations between miRNA expression and hormone levels depended on the type of treatment.

Targeted delivery of doxorubicin and vincristine to lymph cancer: evaluation of novel nanostructured lipid carriers in vitro and in vivo.

PURPOSE: Lymph cancers are heterogeneous malignancies of the hematopoietic and lymphoid tissues. Doxorubicin (DOX) and vincristine (VCR) are commonly used anti-cancer chemotherapeutic drugs, but their clinical uses are associated with dose-limiting systemic toxicity. METHODS: In the present study, DOX and VCR were encapsulated into nanostructured lipid carriers (NLCs) and used them to treat B-cell lymphoma cells through the targeted delivery of DOX and VCR to lymph cancer animal model. RESULTS: DOX and VCR encapsulated NLCs (DOX/VCR NLCs) demonstrated controlled drug release under physiological conditions. In addition, DOX/VCR NLCs exhibited the highest cytotoxicity and synergistic effect of two drugs in B-cell lymphoma cells and the best anti-tumor effect in vivo. CONCLUSION: DOX/VCR NLCs were proved to be more efficacious than the equivalent dose of free DOX and single drug (DOX or VCR) formulation in vitro and in vivo, and significantly reduced the drug-associated systemic toxicity.

Severe Acute Pancreatitis: Gut Barrier Failure, Systemic Inflammatory Response, Acute Lung Injury, and the Role of the Mesenteric Lymph.

BACKGROUND: Severe acute pancreatitis (AP) often leads to distant organ dysfunction with a high morbidity and mortality rate. The most common and earliest organ to fail is the lungs, but the exact pathophysiological mechanisms underlying the disease are still unclear. No successful targeted therapy exists, and treatment is limited to organ supportive care. It is believed that the gut is involved in the development of distant organ failure, as severe AP is associated with changes in the microcirculation, gut permeability/motility, bacterial translocation, and activation of the gut-associated lymphoid tissue (GALT). Experimental evidence implicates the mesenteric lymph as a primary route for these toxic factors to gain access to the systemic circulation. This literature overview was made to survey these mechanisms and the potential of surgical interventions on the thoracic duct as a means of therapy. METHODS: Review of the pertinent English-language literature. RESULTS: In experimental studies, interruption of mesenteric lymphatic flow has preventive qualities for acute lung injury (ALI) in the setting of critical illness with various etiologies. Experimentally, diversion of mesenteric lymph is able to prevent ALI if done before its development, whereas a later intervention partially reduces the lung damage. Few studies have investigated surgical approaches to the thoracic duct in human beings under these circumstances, and the ones that have been performed are of low quality and have conflicting results. It seems likely that the intervention would need to be performed prior to the development of ALI to obtain maximum benefits, which complicates its application clinically, because prediction of ALI cannot today be done with high precision. CONCLUSION: Studies are ongoing to identify the factors carried in mesenteric lymph that may cause end-organ failure (e.g., ALI) and, once recognized, might allow the development of novel targeted agents that would modify the disease course.

Milk Phospholipids Enhance Lymphatic Absorption of Dietary Sphingomyelin in Lymph-Cannulated Rats.

Supplementation with sphingomyelin has been reported to have beneficial effects on disease prevention and health maintenance. However, compared with glycerolipids, intact sphingomyelin and ceramides are poorly absorbed. Therefore, if the bioavailability of dietary sphingomyelin is increased, then the dose administered can be reduced. This study was designed to identify molecular species of ceramide in rat lymph after the ingestion of milk sphingomyelin, and to compare the effect of purified sphingomyelin with milk phospholipids concentrate (MPL, 185 mg sphingomyelin/g) on lymphatic absorption of milk sphingomyelin. Lymph was collected hourly for 6 h from lymph-cannulated rats (n = 8/group) after the administration of a control emulsion (triolein, bovine serum albumin, and sodium taurocholate), a sphingomyelin emulsion (control + purified sphingomyelin), or a MPL emulsion (control + MPL). Molecular species of ceramide in lymph were analyzed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Molecular species of ceramide, containing not only d18:1, but also d17:1 and d16:1 sphingosine with 16:0, 22:0, 23:0, and 24:0 fatty acids (specific to milk sphingomyelin), were increased in rat lymph after the administration of milk sphingomyelin. Their molecular species were similar to those of dietary milk sphingomyelin. Recovery of ceramide moieties from dietary sphingomyelin was 1.28- to 1.80-fold significantly higher in the MPL group than in the sphingomyelin group. Our results demonstrated that dietary sphingomyelin from milk was transported to lymph as molecular species of ceramide hydrolyzed from milk sphingomyelin and co-ingestion of sphingomyelin with glycerophospholipids enhanced the bioavailability of dietary sphingomyelin.

The role of apolipoprotein A-IV in regulating glucagon-like peptide-1 secretion.

Both glucagon-like peptide-1 (GLP-1) and apolipoprotein A-IV (apoA-IV) are produced from the gut and enhance postprandial insulin secretion. This study investigated whether apoA-IV regulates nutrient-induced GLP-1 secretion and whether apoA-IV knockout causes compensatory GLP-1 release. Using lymph-fistula-mice, we first determined lymphatic GLP-1 secretion by administering apoA-IV before an intraduodenal Ensure infusion. apoA-IV changed neither basal nor Ensure-induced GLP-1 secretion relative to saline administration. We then assessed GLP-1 in apoA-IV-/- and wild-type (WT) mice administered intraduodenal Ensure. apoA-IV-/- mice had comparable lymph flow, lymphatic triglyceride, glucose, and protein outputs as WT mice. Intriguingly, apoA-IV-/- mice had higher lymphatic GLP-1 concentration and output than WT mice 30 min after Ensure administration. Increased GLP-1 was also observed in plasma of apoA-IV-/- mice at 30 min. apoA-IV-/- mice had comparable total gut GLP-1 content relative to WT mice under fasting, but a lower GLP-1 content 30 min after Ensure administration, suggesting that more GLP-1 was secreted. Moreover, an injection of apoA-IV protein did not reverse the increased GLP-1 secretion in apoA-IV-/- mice. Finally, we assessed gene expression of GLUT-2 and the lipid receptors, including G protein-coupled receptor (GPR) 40, GPR119, and GPR120 in intestinal segments. GLUT-2, GPR40 and GPR120 mRNAs were unaltered by apoA-IV knockout. However, ileal GPR119 mRNA was significantly increased in apoA-IV-/- mice. GPR119 colocalizes with GLP-1 in ileum and stimulates GLP-1 secretion by sensing OEA, lysophosphatidylcholine, and 2-monoacylglycerols. We suggest that increased ileal GPR119 is a potential mechanism by which GLP-1 secretion is enhanced in apoA-IV-/- mice.

Lympho- and Hemodynamics in Dogs with Acute Experimental Pancreatitis.

Dogs with experimental pancreatitis showed increased lymph fl ow, impaired rheological properties of the lymph and blood plasma, and increased plasma and blood levels of glucose, ALT, and AST.

Modest hyperglycemia prevents interstitial dispersion of insulin in skeletal muscle.

UNLABELLED: Insulin injected directly into skeletal muscle diffuses rapidly through the interstitial space to cause glucose uptake, but this is blocked in insulin resistance. As glucotoxicity is associated with endothelial dysfunction, the observed hyperglycemia in diet-induced obese dogs may inhibit insulin access to muscle cells, and exacerbate insulin resistance. Here we asked whether interstitial insulin diffusion is reduced in modest hyperglycemia, similar to that induced by a high fat diet. METHODS: During normoglycemic (100 mg/dl) and moderately hyperglycemic (120 mg/dl) clamps in anesthetized canines, sequential doses of insulin were injected into the vastus medialis of one hindlimb; the contra-lateral limb served as a control. Plasma samples were collected and analyzed for insulin content. Lymph vessels of the hind leg were also catheterized, and lymph samples were analyzed as an indicator of interstitial insulin concentration. RESULTS: Insulin injection increased lymph insulin in normoglycemic animals, but not in hyperglycemic animals. Muscle glucose uptake was elevated in response to hyperglycemia, however the insulin-mediated glucose uptake in normoglycemic controls was not observed in hyperglycemia. Modest hyperglycemia prevented intra-muscularly injected insulin from diffusing through the interstitial space reduced insulin-mediated glucose uptake. CONCLUSION: Hyperglycemia prevents the appearance of injected insulin in the interstitial space, thus reducing insulin action on skeletal muscle cells.

Simultaneous pharmacokinetic modeling of alkylresorcinols and their main metabolites indicates dual absorption mechanisms and enterohepatic elimination in humans.

BACKGROUND: Alkylresorcinols have proven to be useful biomarkers of whole-grain wheat and rye intake in many nutritional studies. To improve their utility, more knowledge regarding the fate of alkylresorcinols and their metabolites after consumption is needed. OBJECTIVE: The objective of this study was to develop a combined pharmacokinetic model for plasma concentrations of alkylresorcinols and their 2 major metabolites, 3,5-dihydroxybenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)-propanoic acid (DHPPA). METHODS: The model was established by using plasma samples collected from 3 women and 2 men after a single dose (120 g) of rye bran and validated against fasting plasma concentrations from 8 women and 7 men with controlled rye bran intake (23, 45, or 90 g/d). Alkylresorcinols in the lymph and plasma of a pig fed a single alkylresorcinol dose (1.3 mmol) were quantified to assess absorption. Human ileostomal effluent and pig bile after high and low alkylresorcinol doses were analyzed to evaluate biliary alkylresorcinol metabolite excretion. RESULTS: The model contained 2 absorption compartments: 1 that transferred alkylresorcinols directly to the systematic circulation and 1 in which a proportion of absorbed alkylresorcinols was metabolized before reaching the systemic circulation. Plasma concentrations of alkylresorcinols and their metabolites depended on absorption and formation, respectively, and the mean ± SEM terminal elimination half-life of alkylresorcinols (1.9 ± 0.59 h), DHPPA (1.5 ± 0.26 h), and DHBA (1.3 ± 0.22 h) did not differ. The model accurately predicted alkylresorcinol and DHBA concentrations after repeated alkylresorcinol intake but DHPPA concentration was overpredicted, possibly because of poorly modeled enterohepatic circulation. During the 8 h following administration, <2% of the alkylresorcinol dose was recovered in the lymph. DHPPA was identified in both human ileostomal effluent and pig bile, indicating availability of DHPPA for absorption and enterohepatic circulation. CONCLUSION: Intact alkylresorcinols have advantages over DHBA and DHPPA as plasma biomarkers for whole-grain wheat and rye intake because of lower susceptibility to factors other than alkylresorcinol intake.