D-Pinitol from Ceratonia siliqua Is an Orally Active Natural Inositol That Reduces Pancreas Insulin Secretion and Increases Circulating Ghrelin Levels in Wistar Rats.

To characterize the metabolic actions of D-Pinitol, a dietary inositol, in male Wistar rats, we analyzed its oral pharmacokinetics and its effects on (a) the secretion of hormones regulating metabolism (insulin, glucagon, IGF-1, ghrelin, leptin and adiponectin), (b) insulin signaling in the liver and (c) the expression of glycolytic and neoglucogenesis enzymes. Oral D-Pinitol administration (100 or 500 mg/Kg) resulted in its rapid absorption and distribution to plasma and liver compartments. Its administration reduced insulinemia and HOMA-IR, while maintaining glycaemia thanks to increased glucagon activity. In the liver, D-Pinitol reduced the key glycolytic enzyme pyruvate kinase and decreased the phosphorylation of the enzymes AKT and GSK-3. These observations were associated with an increase in ghrelin concentrations, a known inhibitor of insulin secretion. The profile of D-Pinitol suggests its potential use as a pancreatic protector decreasing insulin secretion through ghrelin upregulation, while sustaining glycaemia through the liver-based mechanisms of glycolysis control.

Experts' opinion on inositols in treating polycystic ovary syndrome and non-insulin dependent diabetes mellitus: a further help for human reproduction and beyond.

Introduction: This Experts' opinion provides an updated scientific support to gynecologists, obstetricians, endocrinologists, nutritionists, neurologists and general practitioners on the use of Inositols in the therapy of Polycystic Ovary Syndrome (PCOS) and non-insulin dependent (type 2) diabetes mellitus (NIDDM).Areas covered: This paper summarizes the physiology of Myo-Inositol (MI) and D-Chiro-Inositol (DCI), two important molecules present in human organisms, and their therapeutic role, also for treating infertility. Some deep differences between the physiological functions of MI and DCI, as well as their safety and intestinal absorption are discussed. Updates include new evidence on the efficacy exerted in PCOS by the 40:1 MI/DCI ratio, and the innovative approach based on alpha-lactalbumin to overcome the decreased therapeutic efficacy of Inositols in some patients.Expert opinion: The evidence suggests that MI, alone or with DCI in the 40:1 ratio, offers a promising treatment for PCOS and NIDDM. However, additional studies need to evaluate some still unresolved issues, such as the best MI/DCI ratio for treating NIDDM, the potential cost-effectiveness of reduced gonadotropins administration in IVF due to MI treatment, or the benefit of MI supplementation in ovulation induction with clomiphene citrate in PCOS patients.

Risk of reduced intestinal absorption of myo-inositol caused by D-chiro-inositol or by glucose transporter inhibitors.

Background: D-chiro-inositol (DCI) and glucose transporter inhibitors may inhibit myo-inositol (MI) transporters, and the aim is to clinically evaluate their effect on MI absorption. Research design and methods: Fasting 18 healthy volunteers received orally 6000 mg MI, 6000 mg MI with 1000 mg DCI, and 6000 mg MI with SelectSIEVE® Apple PCQ and Sorbitol, Maltodextrin and Sucralose (PCQ-SMS), in three different phases with a washout period of 7 days. At each phase, blood samples were collected before administration, and every 60 minutes until 540 minutes after administration. MI plasma levels (µmol/L) were quantified by gas chromatography-mass spectrometry; maximum plasma concentration (Cmax), time to reach it (Tmax), and the area under the time-concentration curve of MI (AUC 0-540) were evaluated. Results: The Cmax of MI alone (Tmax = 180min) was 1.29-fold higher than those of MI with DCI (Tmax = 180min) (p < 0.001) and 1.69-fold higher than those of MI with PCQ-SMS (Tmax = 240min) (p < 0.001). The AUC 0-540 was reduced by 19.09% in MI plus DCI (p = 0.0118) and by 31.8% in MI plus PCQ-SMS (p < 0.001) as compared to MI alone. Conclusions: DCI, glucose transporter inhibitors and sugars, such as sorbitol and maltodextrin, seem to inhibit MI absorption, decreasing MI plasma concentration as compared to MI alone.

Pharmacodynamic effects of voglibose administered alone, administered with metformin, and administered with metformin in a fixed-dose combination in healthy Korean subjects
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OBJECTIVE: This study aimed at exploring the effects of metformin on the pharmacodynamics of voglibose, while investigating the pharmacodynamics between a fixed-dose combination (FDC) of voglibose/metformin and coadministered doses of voglibose and metformin tablets in healthy Korean subjects. MATERIALS AND METHODS: A randomized, open-label, 2×3×3 crossover study with a 9-day washout period was conducted in 30 healthy subjects. All subjects received orally administered voglibose alone, individual voglibose and metformin tablets, or FDC 3 times daily for 5 days. Oral sucrose was administered on day -1 (pretreatment) and at 10 minutes after the morning dose of the study drug on day 5 of each period. Plasma glucose and serum insulin were measured over the course of 2 hours following sucrose loading. RESULTS: 21 subjects completed the study. The geometric mean ratios (GMR) of ΔCmax and the AUC of glucose for voglibose plus metformin vs. voglibose alone were 0.995 (90% CI, 0.800 - 1.237) and 0.969 (90% CI, 0.949 - 0.990), respectively; the GMRs for individual tablets vs. FDC were 1.118 (90% CI, 0.930 - 1.344) and 1.010 (90% CI, 0.974 - 1.048), respectively. A relatively smaller number of subjects experienced adverse events when receiving voglibose alone compared to those administered FDC or metformin and voglibose. There were no significant differences in adverse events between individual voglibose and metformin tablets and FDC. CONCLUSION: Coadministered metformin did not have statistically or clinically significant effects on the pharmacodynamics of voglibose in healthy subjects. Glucose levels following sucrose loading seem not to be clinically different between FDC and individual tablets of voglibose and metformin.
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In vitro gastrointestinal biotransformation and characterization of a Desmodium adscendens decoction: the first step in unravelling its behaviour in the human body.

OBJECTIVES: The isolation and identification of the flavonoids present in a decoction of Desmodium adscendens was performed. In view of the oral use of the decoction, this work focused on the stability in gastrointestinal conditions and biotransformation by intestinal microflora in the colon of D-pinitol, vitexin and the flavonoid fraction of the decoction, as a first step in unravelling its behaviour in the human body. METHODS: The freeze-dried decoction was first subjected to column chromatography. Subsequently an enriched flavonoid fraction, was separated by repeated semi-preparative high-performance liquid chromatography (HPLC) or by HPLC-SPE. The isolated compounds were elucidated by NMR. Biotransformation experiments were carried in an in vitro gastrointestinal dialysis model. KEY FINDINGS: The major flavonoids of a decoction of D. adscendens were characterized as vicenin-2, isoschaftoside, schaftoside, 2″-O-xylosylvitexin, 2″-O-pentosyl-C-hexosyl apigenin and a O-hexosyl-C-hexosyl apigenin, tentatively identified as 2″-O-glucosyl-vitexin. During their passage in the gastrointestinal dialysis model, vitexin and C-glycosides thereof were found to be stable. Only the O-glycosidic bonds of O-glycosides of vitexin or isovitexin were hydrolysed during the colonic phase. CONCLUSIONS: A D. adscendens decoction was found to be rich in vitexin and isovitexin glycosides from which vitexin and the C-glycosides thereof were found to be stable in the simulated gastrointestinal tract.

Characterization of SNF472 pharmacokinetics and efficacy in uremic and non-uremic rats models of cardiovascular calcification.

End-stage renal disease is strongly associated with progressive cardiovascular calcification (CVC) and there is currently no therapy targeted to treat CVC. SNF472 is an experimental formulation under development for treatment of soft tissue calcification. We have investigated the pharmacokinetics of SNF472 administration in rats and its inhibitory effects on CVC. SNF472 was studied in three rat models: (1) prevention of vitamin D3-induced CVC with an intravenous SNF472 bolus of 1 mg/kg SNF472, (2) inhibition of progression of vitamin D3-induced CVC with a subcutaneous SNF472 bolus of 10 or 60 mg/kg SNF472, starting after calcification induction, (3) CVC in adenine-induced uremic rats treated with 50 mg/kg SNF472 via i.v. 4h -infusion. Uremic rats presented lower plasma levels of SNF472 than control animals after i.v. infusion. CVC in non-uremic rats was inhibited by 60-70% after treatment with SNF472 and progression of cardiac calcification completely blocked. Development of CVC in uremic rats was inhibited by up to 80% following i.v. infusion of SNF472. SNF472 inhibits the development and progression of CVC in uremic and non-uremic rats in the same range of SNF472 plasma levels but using in each case the required dose to obtain those levels. These results collectively support the development of SNF472 as a novel therapeutic option for treatment of CVC in humans.

Nutritional and Acquired Deficiencies in Inositol Bioavailability. Correlations with Metabolic Disorders.

Communities eating a western-like diet, rich in fat, sugar and significantly deprived of fibers, share a relevant increased risk of both metabolic and cancerous diseases. Even more remarkable is that a low-fiber diet lacks some key components-as phytates and inositols-for which a mechanistic link has been clearly established in the pathogenesis of both cancer and metabolic illness. Reduced bioavailability of inositol in living organisms could arise from reduced food supply or from metabolism deregulation. Inositol deregulation has been found in a number of conditions mechanistically and epidemiologically associated to high-glucose diets or altered glucose metabolism. Indeed, high glucose levels hinder inositol availability by increasing its degradation and by inhibiting both myo-Ins biosynthesis and absorption. These underappreciated mechanisms may likely account for acquired, metabolic deficiency in inositol bioavailability.

Finding the best therapeutic approach for PCOS: the importance of inositol(s) bioavailability.

Broadening clinical evidence has markedly designated inositol(s) as a common and effective therapeutic approach for PCOS and infertility. Although considerable research has been focused on the use in clinical practice of myo-inositol (myo-ins) and D-chiro-inositol (D-chiro-ins), the two major inositol stereoisomers, less attention has been paid to their bioavailability. Therefore, the aim of this paper is to gather and analyze information on inositol(s) bioavailability, to better delineate its optimal concentration for scientific and clinical purposes. Throughout the search in PubMed, Google Scholar, and ResearchGate we identified only two studies that investigated the pharmacokinetic (PK) profile of different myo-ins administrations. This analysis found no advantage in terms of PK for single 4 g dosing of myo-ins compared to 2 g twice a day, which allowed to get a 24-hour coverage, contrary to the singular dose. Indeed, the differences regarding the area under the curve (AUC) between the two PK profiles are linked only to the maximum concentration (Cmax) but not to the time variable. In conclusion, splitting the therapeutic dosage of 4 g myo-ins in two distinct administrations seems to be the best approach for a full-day coverage.

A Randomized, Double-Blind, Placebo-Controlled, Phase II Study of Oral ELND005 (scyllo-Inositol) in Young Adults with Down Syndrome without Dementia.

BACKGROUND: ELND005 (scyllo-Inositol; cyclohexane-1,2,3,4,5,6-hexol) has been evaluated as a potential disease-modifying treatment for Alzheimer's disease (AD). Individuals with Down syndrome (DS) have an increased risk for developing AD dementia. OBJECTIVE: To evaluate the safety and tolerability of ELND005 and to determine its pharmacokinetics (PK) and relationship between PK parameters, safety outcome measures, and exploratory efficacy outcome measures in young adults with DS without dementia. METHODS: This was a prospective, randomized, double-blind, placebo-controlled, parallel-group, three-arm, multicenter Phase II study of the safety and pharmacokinetics of ELND005 administered orally for 4 weeks (ClinicalTrials.gov NCT01791725). Participants who met study eligibility criteria were randomly assigned in a 2 : 1:1 ratio to receive ELND005 at either 250 mg twice daily (BID) or 250 mg once daily (QD) or matching placebo for 4 weeks. RESULTS: There were no apparent treatment group-related trends on cognitive or behavioral measures and there were no SAEs and no deaths in the study. Overall, mean changes from baseline in clinical laboratory parameters, vital sign measurements, electrocardiogram results, and other physical findings were unremarkable. ELND005 accumulation averaged approximately 2-fold with QD dosing, and 3- to 4-fold with BID dosing. CONCLUSION: Overall, treatment of adults with DS with ELND005 at both doses was well tolerated, achieved measurable blood levels and demonstrated no safety findings. Further studies will be needed to test efficacy.

Effects of Food Thickeners on the Inhibitory Effect of Voglibose Oral-disintegrating Tablets on Post-prandial Elevation of Blood Sugar Levels.

The aim of this study was to examine the effects of food thickeners on the pharmacodynamics of voglibose, an α-glucosidase inhibitor. The pharmacodynamics of voglibose were examined in an open-label study in 9 healthy participants after the ingestion of a single oral dose of a voglibose oral-disintegrating tablet, with and without food thickener immersion. The area under the incremental blood sugar concentration-time curve was larger and the rate of increments in the blood sugar concentration was higher with the voglibose oral-disintegrating tablets immersed in the food thickener than with the tablets that were not immersed. Immersing the voglibose oral-disintegrating tablets in the food thickener possibly delayed their disintegration rate. This suggests that commercially available food thickeners may be associated with changes in the disintegration of voglibose oral-disintegrating tablets and should therefore be used carefully in certain clinical situations.

Enhanced Germicidal Efficacy by Co-Delivery of Validamycin and Hexaconazole with Methoxy Poly(ethylene glycol)-Poly(lactide-co-glycolide) Nanoparticles.

Co-delivery system has been proposed in pharmaceutical field aim to synergistic treatments. The combination formulation is also important in traditional pesticides formulations based on the low pest resistance risk and wide fungicidal spectrum. However, co-delivery nanoparticles (NPs) tend to be more environmentally friendly for the sustained-release behaviour and none of toxic organic solvents or dusts. Hence, we constructed co-delivery NPs which could delivery two kinds of pesticides, which function was similar with pesticides combination formulation. The co-delivery NPs of validamycin and hexaconazole were prepared with the amphiphilic copolymer methoxy poly(ethylene glycol)- poly(lactide-co-glycolide) (mPEG-PLGA) used an improved double emulsion method. The chemical structure of mPEG-PLGA copolymer was confirmed using fourier transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance spectroscopy (NMR). The co-delivery NPs all exhibited good size distribution and held sustained-release property. Germicidal efficacy of the co-delivery NPs against Rhizoctonia cerealis was also studied. The germicidal efficacy of co-delivery NPs against Rhizoctonia cerealis was better than that of traditional pesticides formulation. In addition, co-delivery NPs showed a lasting impact against Rhizoctonia cerealis.

Pharmacodynamics and pharmacokinetics of inositol(s) in health and disease.

INTRODUCTION: Inositol and its derivatives comprise a huge field of biology. Myo-inositol is not only a prominent component of membrane-incorporated phosphatidylinositol, but participates in its free form, with its isomers or its phosphate derivatives, to a multitude of cellular processes, including ion channel permeability, metabolic homeostasis, mRNA export and translation, cytoskeleton remodeling, stress response. AREAS COVERED: Bioavailability, safety, uptake and metabolism of inositol is discussed emphasizing the complexity of interconnected pathways leading to phosphoinositides, inositol phosphates and more complex molecules, like glycosyl-phosphatidylinositols. EXPERT OPINION: Besides being a structural element, myo-inositol exerts unexpected functions, mostly unknown. However, several reports indicate that inositol plays a key role during phenotypic transitions and developmental phases. Furthermore, dysfunctions in the regulation of inositol metabolism have been implicated in several chronic diseases. Clinical trials using inositol in pharmacological doses provide amazing results in the management of gynecological diseases, respiratory stress syndrome, Alzheimer's disease, metabolic syndrome, and cancer, for which conventional treatments are disappointing. However, despite the widespread studies carried out to identify inositol-based effects, no comprehensive understanding of inositol-based mechanisms has been achieved. An integrated metabolomics-genomic study to identify the cellular fate of therapeutically administered myo-inositol and its genomic/enzymatic targets is urgently warranted.

Safety and pharmacokinetics of multiple dose myo-inositol in preterm infants.

BACKGROUND: Preterm infants with respiratory distress syndrome (RDS) given inositol had reduced bronchopulmonary dysplasia (BPD), death and severe retinopathy of prematurity (ROP). We assessed the safety and pharmacokinetics of daily inositol to select a dose providing serum levels previously associated with benefit, and to learn if accumulation occurred when administered throughout the normal period of retinal vascularization. METHODS: Infants ≤ 29 wk GA (n = 122, 14 centers) were randomized and treated with placebo or inositol at 10, 40, or 80 mg/kg/d. Intravenous administration converted to enteral when feedings were established, and continued to the first of 10 wk, 34 wk postmenstrual age (PMA) or discharge. Serum collection employed a sparse sampling population pharmacokinetics design. Inositol urine losses and feeding intakes were measured. Safety was prospectively monitored. RESULTS: At 80 mg/kg/d mean serum levels reached 140 mg/l, similar to Hallman's findings. Levels declined after 2 wk, converging in all groups by 6 wk. Analyses showed a mean volume of distribution 0.657 l/kg, clearance 0.058 l/kg/h, and half-life 7.90 h. Adverse events and comorbidities were fewer in the inositol groups, but not significantly so. CONCLUSION: Multiple dose inositol at 80 mg/kg/d was not associated with increased adverse events, achieves previously effective serum levels, and is appropriate for investigation in a phase III trial.

Inositol's and other nutraceuticals' synergistic actions counteract insulin resistance in polycystic ovarian syndrome and metabolic syndrome: state-of-the-art and future perspectives.

The incidence of metabolic syndrome (MetS), type II diabetes (T2D) and polycystic ovarian syndrome (PCOS) has been progressively increasing. Insulin resistance (InsR) seems to play a key role in a majority of phenotypes of these conditions, altering metabolic homeostasis, within muscle, liver, adipose and other tissues. Hyperinsulinemia is often associated with InsR and causes hormonal imbalances especially within ovaries and adrenals. Inositol is a polyalcohol, naturally occurring as nine stereoisomers, including D-chiro-inositol (DCI) and myo-inositol (MI), which have prominent roles in the metabolism of glucose and free fatty acids. MI and DCI have been classified as insulin-sensitizers and seem to adequately counteract several InsR-related metabolic alterations with a safe nutraceutical profile. Based on our analysis of selected studies that investigated MI and/or DCI, we conclude that supplementation with MI and/or DCI complement each other in their metabolic actions and act in synergy with other insulin sensitizing drugs and/or nutraceuticals. Nevertheless, considering the possible severe bias due to different methodologies across published studies, we conclude that there is a need for further studies on larger cohorts and with greater statistical power. These should further clarify outcomes and suitable therapeutic dosages of MI and DCI, possibly based on each patient's clinical status.

A Pharmacokinetic/Pharmacodynamic Drug-Drug Interaction Study of Tofogliflozin (a New SGLT2 Inhibitor) and Selected Anti-Type 2 Diabetes Mellitus Drugs.

OBJECTIVE: Tofogliflozin is an oral hypoglycemic agent with a novel mechanism of action that reduces blood glucose levels by promoting glucose excretion in urine, achieved by selectively inhibiting sodium-glucose co-transporter 2 (SGLT2). We evaluated the effects of several selected anti-type 2 diabetes mellitus (T2DM) drugs-glimepiride, metformin, sitagliptin, pioglitazone, miglitol, nateglinide, and voglibose-on the pharmacokinetics and pharmacodynamics of tofogliflozin, and the effects of tofogliflozin on the pharmacokinetics of these anti-T2DM drugs in healthy male volunteers. METHODS: A single dose of either tofogliflozin alone, one of the anti-T2DM drugs alone, or co-administration of tofogliflozin and the anti-T2DM drug was administered to 108 healthy men. Cmax, AUCinf, and cumulative urine glucose excretion after co-administration of tofogliflozin and each of the anti-T2DM drugs was evaluated relative to the values of those parameters after administration of each drug alone. RESULTS: None of the anti-T2DM drugs had any effect on tofogliflozin exposure. Tofogliflozin had no or little effect on the exposure of any anti-T2DM drug. No anti-T2DM drug had any major effect on the cumulative urine glucose excretion induced by tofogliflozin. There were no safety concerns evident after administration of any drug alone or in co-administration. CONCLUSIONS: Neither the pharmacokinetics nor the pharmacodynamics of tofogliflozin was affected by any of the anti-T2DM drugs evaluated in this study, nor was the pharmacokinetics of any of the anti-T2DM drugs affected by tofogliflozin in healthy male volunteers.

N-Alkylated aziridines are easily-prepared, potent, specific and cell-permeable covalent inhibitors of human ß-glucocerebrosidase.

ß-Glucocerebrosidase deficiency leads to Gaucher disease and is a potential marker of Parkinson's disease. We have identified N-octyl conduritol aziridine as a potent and specific covalent inactivator of GBA1 in living cells. This compound is a promising lead towards a positron emission tomography probe intended to image GBA1 activity.

Descentralização das ações de vigilância epidemiológica em Pernambuco, Brasil / Decentralization of epidemiological surveillance in Pernambuco State, Brazil / Descentralización de la vigilancia epidemiológica en Pernambuco, Brasil

O objetivo do estudo foi analisar a relação entre o processo de descentralização da gestão do Sistema Único de Saúde (SUS) e o desenvolvimento das ações de vigilância epidemiológica em municípios de Pernambuco, Brasil. A estratégia de trabalho consistiu num estudo descritivo e exploratório qualitativo/quantitativo, com a realização de uma pesquisa de caráter documental e entrevistas semiestruturadas com informantes-chave, como também um estudo ecológico espacial e de série temporal, no qual foi traçada uma série histórica de dez anos (2001-2010), utilizando-se indicadores selecionados. O estudo evidenciou que o processo de descentralização em Pernambuco obteve adesão e evoluiu, porém com a existência de desigualdades e fragilidades no seu desenvolvimento, também apontadas pela oscilação nos resultados da série histórica dos indicadores selecionados. Assim, mesmo que o processo de descentralização das ações de vigilância epidemiológica ainda seja incipiente em alguns municípios, sabe-se que o papel de executor das ações promove o empoderamento do nível municipal, quando o mesmo passa a produzir as informações necessárias à tomada de decisão.

The study aimed to analyze the relationship between decentralization of the Brazilian Unified National Health System (SUS) and the development of epidemiological surveillance activities in municipalities (counties) in Pernambuco State, Brazil. This was an exploratory descriptive qualitative and quantitative study, including a document search, completion of semi-structured interviews by key informants, and an ecological spatial and time trend study of selected health indicators, covering a 10-year period (2001-2010). The study showed that municipalities adhered to the decentralization process, which was making progress in Pernambuco, but with inequalities and weaknesses in its development. There was also a fluctuation in the time series for the selected indicators. Thus, even though the decentralization of epidemiological surveillance is still incipient in some municipalities, their protagonist role in implementing the activities promotes empowerment at the local level by producing key information for decision-making.

El objetivo del estudio fue analizar la relación entre el proceso de descentralización del Sistema Único de Salud (SUS) y el desarrollo de acciones de vigilancia epidemiológica en los municipios de Pernambuco, Brasil. La estrategia de trabajo fue un estudio exploratorio descriptivo, cualitativo y cuantitativo, con la realización de una revisión documental, entrevistas semi-estructuradas con informantes clave, y un estudio ecológico espacial con una serie de tiempo de 10 años (2001-2010) de indicadores seleccionados. El estudio mostró que el proceso de descentralización en Pernambuco tiene adhesión y evolucionó, pero con la existencia de desigualdades y debilidades en su desarrollo, revelado también por la oscilación de la serie histórica de los indicadores. A pesar de que el proceso de descentralización de la vigilancia epidemiológica es aún incipiente en algunos municipios, se sabe que el papel de ejecutor de acciones promueve el empoderamiento del nivel municipal, cuando se comienza a producir información necesaria para la toma de decisiones.

Pharmacokinetics and safety of a single intravenous dose of myo-inositol in preterm infants of 23-29 wk.

BACKGROUND: Myo-inositol given to preterm infants with respiratory distress has reduced death, increased survival without bronchopulmonary dysplasia, and reduced severe retinopathy of prematurity in two randomized trials. Pharmacokinetic (PK) studies in extremely preterm infants are needed before efficacy trials. METHODS: Infants born in 23-29 wk of gestation were randomized to a single intravenous (i.v.) dose of inositol at 60 or 120 mg/kg or placebo. Over 96 h, serum levels (sparse sampling population PK) and urine inositol excretion were determined. Population PK models were fit using a nonlinear mixed-effects approach. Safety outcomes were recorded. RESULTS: A single-compartment model that included factors for endogenous inositol production, allometric size based on weight, gestational age strata, and creatinine clearance fit the data best. The central volume of distribution was 0.5115 l/kg, the clearance was 0.0679 l/kg/h, endogenous production was 2.67 mg/kg/h, and the half-life was 5.22 h when modeled without the covariates. During the first 12 h, renal inositol excretion quadrupled in the 120 mg/kg group, returning to near-baseline value after 48 h. There was no diuretic side effect. No significant differences in adverse events occurred among the three groups (P > 0.05). CONCLUSION: A single-compartment model accounting for endogenous production satisfactorily described the PK of i.v. inositol.

ß-Glucosidase 2 (GBA2) activity and imino sugar pharmacology.

ß-Glucosidase 2 (GBA2) is an enzyme that cleaves the membrane lipid glucosylceramide into glucose and ceramide. The GBA2 gene is mutated in genetic neurological diseases (hereditary spastic paraplegia and cerebellar ataxia). Pharmacologically, GBA2 is reversibly inhibited by alkylated imino sugars that are in clinical use or are being developed for this purpose. We have addressed the ambiguity surrounding one of the defining characteristics of GBA2, which is its sensitivity to inhibition by conduritol B epoxide (CBE). We found that CBE inhibited GBA2, in vitro and in live cells, in a time-dependent fashion, which is typical for mechanism-based enzyme inactivators. Compared with the well characterized impact of CBE on the lysosomal glucosylceramide-degrading enzyme (glucocerebrosidase, GBA), CBE inactivated GBA2 less efficiently, due to a lower affinity for this enzyme (higher KI) and a lower rate of enzyme inactivation (k(inact)). In contrast to CBE, N-butyldeoxygalactonojirimycin exclusively inhibited GBA2. Accordingly, we propose to redefine GBA2 activity as the ß-glucosidase that is sensitive to inhibition by N-butyldeoxygalactonojirimycin. Revised as such, GBA2 activity 1) was optimal at pH 5.5-6.0; 2) accounted for a much higher proportion of detergent-independent membrane-associated ß-glucosidase activity; 3) was more variable among mouse tissues and neuroblastoma and monocyte cell lines; and 4) was more sensitive to inhibition by N-butyldeoxynojirimycin (miglustat, Zavesca®), in comparison with earlier studies. Our evaluation of GBA2 makes it possible to assess its activity more accurately, which will be helpful in analyzing its physiological roles and involvement in disease and in the pharmacological profiling of monosaccharide mimetics.

Potential role and therapeutic interests of myo-inositol in metabolic diseases.

Several inositol isomers and in particular myo-inositol (MI) and D-chiro-inositol (DCI), were shown to possess insulin-mimetic properties and to be efficient in lowering post-prandial blood glucose. In addition, abnormalities in inositol metabolism are associated with insulin resistance and with long term microvascular complications of diabetes, supporting a role of inositol or its derivatives in glucose metabolism. The aim of this review is to focus on the potential benefits of a dietary supplement of myo-inositol, by far the most common inositol isomer in foodstuffs, in human disorders associated with insulin resistance (polycystic ovary syndrome, gestational diabetes mellitus or metabolic syndrome) or in prevention or treatment of some diabetic complications (neuropathy, nephropathy, cataract). The relevance of such a nutritional strategy will be discussed for each context on the basis of the clinical and/or animal studies. The dietary sources of myo-inositol and its metabolism from its dietary uptake to its renal excretion will be also covered in this review. Finally, the actual insights into inositol insulin-sensitizing effects will be addressed and in particular the possible role of inositol glycans as insulin second messengers.