Higher Concentrations Of Myo-inositol Research Articles

Metabolomics approaches in pancreatic adenocarcinoma: tumor metabolism profiling predicts clinical outcome of patients

BackgroundPancreatic adenocarcinomas (PAs) have very poor prognoses even when surgery is possible. Currently, there are no tissular biomarkers to predict long-term survival in patients with PA. The aims of this study were to (1) describe the metabolome of pancreatic parenchyma (PP) and PA, (2) determine the impact of neoadjuvant chemotherapy on PP and PA, and (3) find tissue metabolic biomarkers associated with long-term survivors, using metabolomics analysis.Methods1H high-resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR) spectroscopy using intact tissues was applied to analyze metabolites in PP tissue samples (n = 17) and intact tumor samples (n = 106), obtained from 106 patients undergoing surgical resection for PA.ResultsAn orthogonal partial least square-discriminant analysis (OPLS-DA) showed a clear distinction between PP and PA. Higher concentrations of myo-inositol and glycerol were shown in PP, whereas higher levels of glucose, ascorbate, ethanolamine, lactate, and taurine were revealed in PA. Among those metabolites, one of them was particularly obvious in the distinction between long-term and short-term survivors. A high ethanolamine level was associated with worse survival. The impact of neoadjuvant chemotherapy was higher on PA than on PP.ConclusionsThis study shows that HRMAS NMR spectroscopy using intact tissue provides important and solid information in the characterization of PA. Metabolomics profiling can also predict long-term survival: the assessment of ethanolamine concentration can be clinically relevant as a single metabolic biomarker. This information can be obtained in 20 min, during surgery, to distinguish long-term from short-term survival.

Metabolic profiling of Commiphora wightii (guggul) reveals a potential source for pharmaceuticals and nutraceuticals

Guggul gum resin from Commiphora wightii (syn. Commiphoramukul) has been used for centuries in Ayurveda to treat a variety of ailments. The NMR and GC–MS based non-targeted metabolite profiling identified 118 chemically diverse metabolites including amino acids, fatty acids, organic acids, phenolic acids, pregnane-derivatives, steroids, sterols, sugars, sugar alcohol, terpenoids, and tocopherol from aqueous and non-aqueous extracts of leaves, stem, roots, latex and fruits of C. wightii. Out of 118, 51 structurally diverse aqueous metabolites were characterized by NMR spectroscopy. For the first time quinic acid and myo-inositol were identified as the major metabolites in C. wightii. Very high concentration of quinic acid was found in fruits (553.5±39.38mgg−1 dry wt.) and leaves (212.9±10.37mgg−1 dry wt.). Similarly, high concentration of myo-inositol (168.8±13.84mgg−1 dry wt.) was observed from fruits. The other metabolites of cosmeceutical, medicinal, nutraceutical and industrial significance such as α-tocopherol, n-methylpyrrolidone (NMP), trans-farnesol, prostaglandin F2, protocatechuic, gallic and cinnamic acids were identified from non-aqueous extracts using GC–MS. These important metabolites have thus far not been reported from this plant. Isolation of a fungal endophyte, (Nigrospora sps.) from this plant is the first report. The fungal endophyte produced a substantial quantity of bostrycin and deoxybostrycin known for their antitumor properties. Very high concentrations of quinic acid and myo-inositol in leaves and fruits; a substantial quantity of α-tocopherol and NMP in leaves, trans-farnesol in fruits, bostrycin and deoxybostrycin from its endophyte makes the taxa distinct, since these metabolites with medicinal properties find immense applications as dietary supplements and nutraceuticals.

Effects of inositol, inositol-generating phytase B applied alone, and in combination with 6-phytase A to phosphorus-deficient diets on laying performance, eggshell quality, yolk cholesterol, and fatty acid deposition in laying hens

Phytase B, a product of Aspergillus niger phyB gene expressed in Trichoderma reesei, which increased myo-inositol concentrations in 20 mM sodium phytate solution 7.5-fold during 120-min incubation, a combination of phytase B with 6-phytase A, and pure myo-inositol were tested as feed supplements in Bovans Brown laying hens. In the 2-factorial experiment (2×5), birds from wk 50 to 62 were fed 2 basal diets, corn-soybean (CSM) or wheat-soybean (WSM), using 12 one-hen cages per treatment. For both basal diets, the dietary treatments included negative control (0.08% nonphytate P in CSM, 0.13% nonphytate P in WSM; NC); internal control groups, NC+0.04% nonphytate P from monocalcium phosphate, MCP (IC); NC+0.1% of myo-inositol (Inos), NC+phytase B at 1,300 units of phytase B-acid phosphatase activity (AcPU)/kg (PhyB), NC+phytase B at 1,300 AcPU/kg+6-phytase A at 300 FTU/kg (PhyA+B). Feed intake, laying performance, and eggshell quality were determined. The total lipid and cholesterol contents as well as fatty acid profile were assessed in egg yolks collected from hens fed CSM diets, as was fatty acid profile. The hens fed the WSM diet consumed significantly more feed, laid a higher mass of eggs daily with higher mean weights, and had a higher hen-day egg production than the birds receiving the CSM diets. Similarly, higher values for yolk weights, shell weights, shell thickness, shell density, and breaking strengths were determined in the eggs laid by the hens fed the WSM diets. In hens fed either the CSM diets with phytase B alone, or in combination with 6-phytase A, enhanced feed intakes, egg mass, and hen-day egg production were recorded. Phytases also enhanced the eggshell quality parameters in the hens fed both variants of the diets. Phytase B alone, or in combination with 6-phytase A, reduced the total lipid and cholesterol concentrations in egg yolks collected from the hens fed the CSM diets, whereas the combination of both phytases improved the n-6:n-3 polyunsaturated fatty acids ratio. In the CSM diets, the supplemental myo-inositol suppressed feed intakes, reduced egg production, had no effect on eggshell quality and reduced the deposition of eicosanoid fatty acids in yolks. When comparing the effects of feeding MCP, myo-inositol, and phytases on the nutritional quality of the eggs laid by the hens fed phosphorus-deficient CSM diets, it seems that the enhancements in nutritional quality cannot be attributed solely to higher phosphorus level or higher concentrations of myo-inositol.

Contributions in astrocytes of SMIT1/2 and HMIT to myo-inositol uptake at different concentrations and pH

myo-Inositol is important for cell signaling both in cytoplasm and in intracellular organelles. It is required in the plasma membrane and cytoplasm for maintained synthesis of the second messengers, inositoltrisphosphate (IP3) and diacylglycerol (DAG) from phosphatidylinositol bisphosphate (PIP2), and in organelles as precursor for synthesis of complex signaling phospholipids and inositolphosphates from IP3 and PIP2. myo-Inositol must be taken up into the cell where its is used, because neither neurons nor astrocytes synthesize it. It is also an osmolyte, taken up in response to surrounding hyperosmolarity and released during hypo-osmolarity. There are three myo-inositol transporters, the Na+-dependent SMIT1 and SMIT2, and HMIT, which co-transports myo-inositol with H+. Their relative expressions in astrocytes and neurons are unknown. Uptake kinetics for myo-inositol in astrocytes has repeatedly been determined, but always on the assumption of only one component, leaving kinetics for the individual transporters unknown. This paper demonstrates that astrocytes obtained directly from the brain express SMIT1 and HMIT, but little SMIT2, and that all three transporters are expressed in neurons. Cultured mouse astrocytes show a high-affinity/low-capacity myo-inositol uptake (Vmax: 60.0±3.0pmol/min per mg protein; Km: 16.7±2.6μM), mediated by SMIT1 and perhaps partly by SMIT2. It was determined in cells pre-treated with HMIT-siRNA and confirmed by specific inhibition of SMIT. However at physiologically relevant myo-inositol concentrations most uptake is by a lower-affinity/higher-capacity uptake, mediated by HMIT (Vmax: 358±60pmol/min per mg protein; Km: 143±36μM) and determined by subtraction of SMIT-mediated from total uptake. At high myo-inositol concentrations, its uptake is inhibited by incubation in medium with increased pH, and increased during intracellular acidification with NH4Cl. This is in agreement with literature data for HMIT alone. At low concentration, where SMIT1/2 activity gains importance, myo-inositol uptake is reduced by ammonia-induced intracellular acidification, consistent with the transporter’s pH sensitivity reported in the literature.

Characterization of traditional Spanish edible plant syrups based on carbohydrate GC–MS analysis

Carbohydrate composition of three traditional plant syrups from Spain, namely palm honey (miel de palma), must syrup (arrope) and sugarcane honey (miel de caña), is described for the first time in this paper. Palm honeys were characterized by their relatively high concentrations of myo-inositol, whereas must syrups showed high values of monosaccharides and the presence of scyllo- and myo-inositol. Difructose anhydrides (DFAs) were also detected in must syrups; their content being dependent on the processing conditions and pH of the sample. Sugarcane honeys showed a different carbohydrate composition to that of edible molasses, with higher contents of monosaccharides and the presence of kestoses. The hydroxymethylfurfural (HMF) content of all the plant syrups analyzed was also determined: must syrups showed the highest values, followed by sugarcane honeys and finally by palm honeys, which displayed very low values. Preliminary results here reported provide the basis for a better understanding of the composition of plant syrups for further application in control of their authenticity.

Astrocytic alkalinization by therapeutically relevant lithium concentrations: implications for myo-inositol depletion

One theory for therapeutic effects of the lithium ion (Li+) in bipolar disorder is that myo-inositol, needed for phospholipase C-mediated signaling, is depleted by Li(+)-induced inhibition of inositolphosphate hydrolysis or of myo-inositol uptake, an effect demonstrated in cultured mouse astrocytes at high myo-inositol concentrations. In contrast, myo-inositol uptake is inhibited at low concentrations, reflecting that it occurs both by the high-affinity Na(+)-dependent myo-inositol transporter (SMIT) and the lower-affinity H(+)-dependent inositol transporter (HMIT). Increased intracellular pH (pHi) stimulates SMIT but inhibits HMIT, suggesting that the effect of Li+ could be caused by intracellular alkalinization. In this study, we therefore investigated Li+ effects on intracellular pH in astrocytes, measured by 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) fluorescence. Chronic treatment with the therapeutically relevant Li+ concentration of 1 mM for 2 or 3 weeks increased pHi by approximately 0.10, whereas 0.5 mM was ineffective, and 2 mM caused a larger increase. The alkalinization resulted from acute stimulation of the Na+/H+ exchanger (NHE) by extracellular Li+, demonstrated after acid load with NH4Cl. In response to continuous stimulation, NHE1 mRNA was down-regulated, but protein was not. Chronic treatment with pharmacologically relevant Li+ concentrations increases pHi in astrocytes, creating conditions for decreased uptake of high myo-inositol concentrations and increased uptake of low concentrations. The pharmacological relevance of this effect is supported by literature data suggesting brain acidosis in bipolar patients and by preliminary observations that carbamazepine and valproate also increase pHi in astrocytes. Stimulation of NHE1-stimulated sodium ion uptake might also trigger uptake of chloride ions and osmotically obliged water.

Additive Effects of HIV and Chronic Methamphetamine Use on Brain Metabolite Abnormalities

Proton magnetic resonance spectroscopy (1H-MRS) showed decreased neuronal marker N-acetylaspartate and increased glial marker myo-inositol in subjects with chronic methamphetamine use and in subjects infected with HIV. The authors sought to determine whether HIV and a history of chronic methamphetamine use might have additive or interactive effects on brain metabolite abnormalities. 1H-MRS was performed in 68 HIV-positive subjects (24 with a history of chronic methamphetamine use with a lifetime exposure of a mean of 2,167 g [SD=2,788] and last use a mean of 4.9 months earlier [SD=6.0]; 44 with no history of drug abuse) and 75 HIV-negative subjects (36 with a history of chronic methamphetamine use with a lifetime exposure of a mean of 8,241 g [SD=16,850] and last use a mean of 6.3 months earlier [SD=7.8]; 39 with no history of drug abuse). Concentrations of N-acetylaspartate, creatine, choline, and myo-inositol were measured in the frontal cortex, frontal white matter, and basal ganglia. HIV-negative subjects with a history of chronic methamphetamine use showed lower concentrations of the neuronal marker N-acetylaspartate in the frontal white matter and basal ganglia and higher concentrations of choline compounds and the glial marker myo-inositol in the frontal cortex, relative to subjects with no history of drug abuse. HIV-positive status was associated with lower concentrations of N-acetylaspartate and creatine in the frontal cortex and higher concentrations of myo-inositol in the white matter, compared with HIV-negative status. Compared to the mean concentrations of metabolites in HIV-negative subjects with no history of drug abuse, the mean concentrations in subjects with HIV and chronic methamphetamine use showed additive effects on N-acetylaspartate in all three regions (-9% in the basal ganglia, -7% in the frontal white matter, and -6% in the frontal gray matter), on creatine in the basal ganglia (-7%), and on myo-inositol in the frontal white matter (+11%). The combined effects of HIV and chronic methamphetamine use were consistent with an additive model, suggesting additional neuronal injury and glial activation due to the comorbid conditions.

Follicular fluid and serum concentrations of myo-inositol in patients undergoing IVF: relationship with oocyte quality

The follicular microenvironment is an important determinant of oocyte development. The aim of this study was to examine whether the myo-inositol (MI) content in human follicular fluid (FF) was associated with better oocyte quality. A total of 53 patients treated with IVF was recruited to a prospective observational study. FF and serum samples collected were divided into two groups: group A consisted of FF associated with matured and fertilized oocytes, whilst group B was from follicles with immature and unfertilized oocytes. Patient's age, total ampoules of HMG used, days of stimulation, basal levels of FSH, estradiol (E(2)) levels on the day of HCG, and serum MI content were not significantly different between the two groups. FF volume and its MI content were significantly higher in group A compared with group B (P < 0.05). The levels of MI in FF were positively correlated with the amount of E(2) in their corresponding FF samples and also correlated with embryo quality. We propose that higher concentrations of MI and E(2) in human FF appear to play a role in follicular maturity and provide a marker of good quality oocytes.

Kinetics of myo-inositol transport in rat ocular lens.

Myo-inositol (MI) influx as a function of concentration in rat lens consisted of a saturable component, fit by a rectangular hyperbola, and a linear component which was more distinct at high myo-inositol concentrations suggesting passive diffusion. The hyperbolic component was half-maximally saturated (Kt) at 61.3 microM and had a maximal transport rate (Jmax) of 44.6 mumol/kg wet wt/h. The linear component had an apparent permeability coefficient of 1.44 x 10(-6) s-1. Sorbitol, which distributed rapidly in the extracellular space (6.83 ml/100 g wet wt), also appeared to enter the intracellular space with a permeability coefficient of 1.37 x 10(-6) s-1, similar to that of myo-inositol. The influx of myo-inositol was critically dependent on the concentration of extracellular sodium consistent with a sodium-myo-inositol cotransport. The kinetics of influx activation by sodium suggested an apparent 2:1 coupling ratio for sodium and myo-inositol. When potassium was used as sodium substitute, a significantly stronger influx inhibition was observed than with nondepolarizing sodium substitutes, indicating that myo-inositol was driven by the electrochemical gradient of sodium rather than the chemical gradient only. Reducing the extracellular Na concentration increased the MI concentration at which transport was half-maximally activated, suggesting an ordered binding sequence of Na followed by MI. Myo-inositol influx was competitively inhibited by phlorizin with an inhibitory coefficient (Ki) of 35 microM. Phloretin also was capable of inhibition but with a much lesser efficacy. Myo-inositol desaturates from the lens at a rate of 0.00862 h-1. Approximately 19% of the efflux can be inhibited with phlorizin, suggesting that it represents carrier-mediated flux. The phlorizin insensitive flux has a rate of 0.00695 h-1 or 1.93 x 10(-6) s-1, similar to the Na-independent passive influx. MI influx is due to a Na-dependent, phlorizin-sensitive active transport while the efflux consists largely of a phlorizin-independent passive leakage.

Quantification of serum 1,5-anhydroglucitol in uremic and diabetic patients by liquid chromatography/mass spectrometry

We developed a new method for measuring serum 1,5-anhydroglucitol (1,5-AG), using liquid chromatography/atmospheric pressure chemical-ionization mass spectrometry (LC/MS). With this method we measured serum 1,5-AG concentrations in uremic and diabetic patients and compared these values with those determined by an enzymatic method. Serum 1,5-AG concentrations were significantly less in the undialyzed and dialyzed uremic patients and in diabetic patients; the values in the dialyzed patients decreased after hemodialysis. In uremic patients with high concentrations of serum myo-inositol, the 1,5-AG values determined by LC/MS were significantly lower than those determined enzymatically. There was no significant correlation between 1,5-AG and fructosamine in the uremic patients. These results demonstrate that serum 1,5-AG cannot be used as an index for glycemic control in uremic patients and that the LC/MS method is indicated in uremic patients with high concentrations of myo-inositol.

Myo‐Inositol Transport in Mouse Astroglia‐Rich Primary Cultures

Uptake of radiolabeled myo-inositol was studied in astroglia-rich primary cultures derived from neonatal mouse brains. The uptake was saturable in the presence of Na+ with a Km of 25 microM and a Vmax of 60 pmol.min-1.(mg protein)-1, suggesting a high-affinity transport system for myo-inositol in astroglial cells. In addition, a Na(+)-independent, nonsaturable component was found. Carrier-mediated uptake was not inhibited by cytochalasin B (50 microM), but was reduced by depolarizing concentrations of K+ and, to different extents, in the presence of phloretin, ouabain, or amiloride (1 mM each). scyllo-Inositol, glucose, and galactose also reduced myo-inositol uptake; inhibition by the two hexoses was not reversed in the presence of 0.4 mM sorbinil. On the other hand, uptake of 2-deoxyglucose was not inhibited by high concentrations of myo-inositol. Preincubation of the cells with glucose-free or inositol-free medium stimulated uptake of myo-inositol and preincubation with 25 mM glucose in the presence of 0.4 mM sorbinil had no effect on the rate of uptake. The results suggest that myo-inositol is taken up into the astroglial cells by a transport mechanism that is distinct from that of glucose and probably is an active one. Sorbitol pathway activity does not interfere with myo-inositol uptake.

Osmoregulatory changes in myo-inositol transport by renal cells.

Renal medullary cells contain high concentrations of myo-inositol, sorbitol, betaine, and glycerophosphocholine, whose levels vary with urinary osmolality. Accumulation of these "compatible" organic osmolytes is believed to help the cells osmoregulate in response to the high extracellular osmolality that occurs as part of the urinary concentrating mechanism. MDCK cells (a line from dog kidney) were previously shown to accumulate myo-inositol in response to increased medium osmolality. We demonstrate here that this accumulation requires the presence of myo-inositol in the medium, implying that the myo-inositol is not synthesized by the cells but rather is transported into them from the extracellular solution. The MDCK cells contain sodium-dependent myo-inositol transporters. Relative to isotonic controls, sodium-dependent myo-inositol uptake is higher in cells exposed to increased osmolality either acutely (1-7 days) or chronically (greater than 1 year). Transport is further enhanced when the cells are cultured in myo-inositol-free medium. The transport has both high- and low-affinity components. The observed changes in transport involve changes in maximal velocity of the high-affinity component but not in its Km. We conclude that renal cells can osmoregulate by changing the number (or, less likely, the transport turnover rate) of functioning sodium-dependent myo-inositol transporters.

Inositol uptake by cultured isolated rat Schwann cells

The uptake of radiolabeled myo-inositol by Schwann cells isolated from the sciatic nerve of 2–4 day old rats was found to occur by a saturable, sodium-dependent phlorizin-inhibited mechanism with an estimated K m of 30μM. The system was inhibited by galactose and glucose but not by galactitol. At high concentrations of myo-inositol, a diffusion-like process appeared to be functional. The characteristics of the saturable system are very similar to those of myo-inositol uptake by the endoneural fascicle preparation of sciatic nerve.

Properties of mouse α-galactosidase

α-Galactosidase has been examined in various murine tissues using the substrate 4-methylumbelliferyl-α-galactoside. Mouse liver appears to contain a single major form of the enzyme, as judged by chromatography and electrophoresis. The enzyme was purified 467-fold with a yield of about 40% by a method involving chromatography on Concanavalin A-Sepharose. It has maximal activity at pH 4.2, a K m value of 1.4 mM, an energy of activation of 16 400 cal/mol, and a molecular weight of 150 000 at pH 5.2. It is inhibited at high concentrations of myoinositol and appears to contain N-acetylneuraminic acid. In these characteristics it resembles human α-galactosidase A. The enzyme from various tissues differs in electrophoretic mobility. After treatment with neuraminidase, however, the enzyme from all tissues comigrates as a single band of activity. By this criterion the α-galactosidase of liver is most heavily sialylated and that from kidney the least. As estimated by gel filtration, the enzyme from liver and kidney exists as species of molecular weight 320 000, 150 000 and 70 000, depending upon pH and ionic strength. This appears to be the result of aggregation of the enzyme, since the forms are interconvertible and under some conditions a single molecular weight species is observed. The liver enzyme is primarily lysosomal, while the kidney enzyme is distributed approximately equally between lysosomal and microsomal fractions.

The distribution of radioactive myoinositol in the reproductive tract of the male rat.

Department of Chemical Pathology, Tel Aviv University-Sackler Medical School, and Institute of Endocrinology, Chaim Sheba Medical Center, Tel Hashomer, Israel (Received 4th November 1974) In various mammalian species, high concentrations of myoinositol have been found in seminal fluid and in male reproductive organs (Mann, 1964; Eisenberg & Bolden, 1964). In the work reported here, the fate of radioactive myoinositol after intraperitoneal injection was studied in mature male rats and in bilaterally nephrectomized rats, because they cannot catabolize myoinositol (Howard & Anderson, 1967). The distribution of radioactivity among the male reproductive organs and glandular secretions was similar in bilaterally nephrectomized and intact animals (Table 1). Radioactive inositol was accumulated avidly, within 2 hr, by the coagulating gland and seminal vesicle, whereas the prostate, epididymis and ductus deferens concentrated inositol less actively. Approximately 24 hr was required for the radioactivity (d/min/g wet wt) of the secretion of the coagulating gland, seminal vesicle