Turnover rate of coenzyme A in mouse brain and liver.

Coenzyme A (CoA) is a fundamental cofactor involved in a number of important biochemical reactions in the cell. Altered CoA metabolism results in severe conditions such as pantothenate kinase-associated neurodegeneration (PKAN) in which a reduction of the activity of pantothenate kinase isoform 2 (PANK2) present in CoA biosynthesis in the brain consequently lowers the level of CoA in this organ. In order to develop a new drug aimed at restoring the sufficient amount of CoA in the brain of PKAN patients, we looked at its turnover. We report here the results of two experiments that enabled us to measure the half-life of pantothenic acid, free CoA (CoASH) and acetylCoA in the brains and livers of male and female C57BL/6N mice, and total CoA in the brains of male mice. We administered (intrastriatally or orally) a single dose of a [13C3-15N-18O]-labelled coenzyme A precursor (fosmetpantotenate or [13C3-15N]-pantothenic acid) to the mice and measured, by liquid chromatography-mass spectrometry, unlabelled- and labelled-coenzyme A species appearance and disappearance over time. We found that the turnover of all metabolites was faster in the liver than in the brain in both genders with no evident gender difference observed. In the oral study, the CoASH half-life was: 69 ± 5 h (male) and 82 ± 6 h (female) in the liver; 136 ± 14 h (male) and 144 ± 12 h (female) in the brain. AcetylCoA half-life was 74 ± 9 h (male) and 71 ± 7 h (female) in the liver; 117 ± 13 h (male) and 158 ± 23 (female) in the brain. These results were in accordance with the corresponding values obtained after intrastriatal infusion of labelled-fosmetpantotenate (CoASH 124 ± 13 h, acetylCoA 117 ± 11 and total CoA 144 ± 17 in male brain).

Ocoxin as a complement to first line treatments in cancer.

Chemotherapy and radiotherapy are the most frequent treatment for patients suffering from malignant progression of cancer. Even though new treatments are now being implemented, administration of these chemotherapeutic agents remains as the first line option in many tumor types. However, the secondary effects of these compounds represent one of the main reasons cancer patients lose life quality during disease progression. Recent data suggests that Ocoxin, a plant extract and natural compound based nutritional complement rich in antioxidants and anti-inflammatory mediators exerts a positive effect in patients receiving chemotherapy and radiotherapy. This mixture attenuates the chemotherapy and radiotherapy-related side effects such as radiation-induced skin burns and mucositis, chemotherapy-related diarrhea, hepatic toxicity and blood-infection. Moreover, it has been proven to be effective as anticancer agent in different tumor models both in vitro and in vivo, potentiating the cytotoxic effect of several chemotherapy compounds such as Lapatinib, Gemcitabine, Paclitaxel, Sorafenib and Irinotecan. The aim of this review is to put some light on the potential of this nutritional mixture as an anticancer agent and complement for the standard chemotherapy routine.

Fosmetpantotenate (RE-024), a phosphopantothenate replacement therapy for pantothenate kinase-associated neurodegeneration: Mechanism of action and efficacy in nonclinical models.

In cells, phosphorylation of pantothenic acid to generate phosphopantothenic acid by the pantothenate kinase enzymes is the first step in coenzyme A synthesis. Pantothenate kinase 2, the isoform localized in neuronal cell mitochondria, is dysfunctional in patients with pantothenate kinase-associated neurodegeneration. Fosmetpantotenate is a phosphopantothenic acid prodrug in clinical development for treatment of pantothenate kinase-associated neurodegeneration, which aims to replenish phosphopantothenic acid in patients. Fosmetpantotenate restored coenzyme A in short-hairpin RNA pantothenate kinase 2 gene-silenced neuroblastoma cells and was permeable in a blood-brain barrier model. The rate of fosmetpantotenate metabolism in blood is species-dependent. Following up to 700 mg/kg orally, blood exposure to fosmetpantotenate was negligible in rat and mouse, but measurable in monkey. Consistent with the difference in whole blood half-life, fosmetpantotenate dosed orally was found in the brains of the monkey (striatal dialysate) but was absent in mice. Following administration of isotopically labeled-fosmetpantotenate to mice, ~40% of liver coenzyme A (after 500 mg/kg orally) and ~50% of brain coenzyme A (after 125 µg intrastriatally) originated from isotopically labeled-fosmetpantotenate. Additionally, 10-day dosing of isotopically labeled-fosmetpantotenate, 12.5 µg, intracerebroventricularly in mice led to ~30% of brain coenzyme A containing the stable isotopic labels. This work supports the hypothesis that fosmetpantotenate acts to replace reduced phosphopantothenic acid in pantothenate kinase 2-deficient tissues.

Mutations in SLC5A6 associated with brain, immune, bone, and intestinal dysfunction in a young child.

The human sodium-dependent multivitamin transporter (hSMVT) is a product of the SLC5A6 gene and mediates biotin, pantothenic acid, and lipoate uptake in a variety of cellular systems. We report here the identification of mutations R94X, a premature termination, and R123L, a dysfunctional amino acid change, both in exon 3 of the SLC5A6 gene in a child using whole genome-scanning. At 15 months of age, the child showed failure to thrive, microcephaly and brain changes on MRI, cerebral palsy and developmental delay, variable immunodeficiency, and severe gastro-esophageal reflux requiring a gastrostomy tube/fundoplication, osteoporosis, and pathologic bone fractures. After identification of the SLC5A6 mutations, he responded clinically to supplemental administration of excess biotin, pantothenic acid, and lipoate with improvement in clinical findings. Functionality of the two mutants was examined by 3H-biotin uptake assay following expression of the mutants in human-derived intestinal HuTu-80 and brain U87 cells. The results showed severe impairment in biotin uptake in cells expressing the mutants compared to those expressing wild-type hSMVT. Live cell confocal imaging of cells expressing the mutants showed the R94X mutant to be poorly tolerated and localized in the cytoplasm, while the R123L mutant was predominantly retained in the endoplasmic reticulum. This is the first reporting of mutations in the SLC5A6 gene in man, and suggests that this gene is important for brain development and a wide variety of clinical functions.

Depth-dependent stratum corneum permeability in human skin in vitro.

The stratum corneum (SC), a permeable membrane, limits percutaneous penetration. As SC chemical and structural properties responsible for skin barrier function appear depth-related, we conducted an in vitro dermatopharmacokinetic study on intact and adhesive tape-stripped skin samples to clarify whether SC is a homogeneous barrier for chemical transport. SC concentration-thickness profiles were determined for four C-14 labeled model chemicals, panthenol, benzoic acid, paraoxon and butenafine, using the tape-stripping approach. Data analysis with the unsteady-state diffusion equation of Fick's second law permitted a chemical diffusion coefficient in SC. To evaluate the consistency of SC permeability from its surface to lower levels, the skin was tape-stripped five to 10 times to remove the upper cell layers before chemical application, such that diffusion coefficients could be determined from three SC depth levels (0, 5 and 10 tape strips). Results suggested the depth-dependency of SC permeability to panthenol, benzoic acid and butenafine; the diffusion coefficient of panthenol decreased significantly after the first five tape strips and subsequently remained consistent. A progressive increase in diffusion coefficients of benzoic acid and butenafine was observed as tape-stripping levels increased. The removal of superficial SC did not result in a significant difference in the paraoxon diffusion coefficient. For individual chemicals, a variation in the diffusion coefficient from SC surface to deeper layers agreed with the change of the diffusion coefficient over time in intact skin. Characterization of the SC properties contributing to the depth-dependent SC permeability will hopefully provide further insight to skin penetration/decontamination. Copyright © 2016 John Wiley & Sons, Ltd.

Release of betaine and dexpanthenol from vitamin E modified silicone-hydrogel contact lenses.

PURPOSE: To develop a contact lens system that will control the release of an osmoprotectant and a moisturizing agent with the aim to reduce symptoms of ocular dryness. MATERIALS AND METHODS: Profiles of the release of osmoprotectant betaine and moisturizing agent dexpanthenol from senofilcon A and narafilcon B contact lenses were determined in vitro under sink conditions. Both types of lenses were also infused with vitamin E to increase the duration of drug release due to the formation of the vitamin E diffusion barriers in the lenses. The release profiles from vitamin E-infused lenses were compared with those from the control lenses. RESULTS: Both dexpanthenol and betaine are released from commercial silicone hydrogel lenses for only about 10 min. Vitamin E loadings into contact lenses at about 20-23% can increase the release times to about 10 h, which is about 60 times larger compared to the control unmodified lenses. CONCLUSIONS: Vitamin E-loaded silicone hydrogel contact lenses released betaine and dexpanthenol in a controlled fashion.

[The effect of a water-soluble vitamins on the activity of some enzymes in diabetes].

Intramuscular injections of the vitamin complex containing: thiamine chloride (B1), riboflavin (B2), lipoic acid (N), calcium pantothenate (B5), pyridoxine hydrochloride (B6), folic acid (B9), ascorbic acid (C) can reduce the blood glucose level in serum of rats with alloxan diabetes, stabilize activity of some enzymes of energy metabolism, lactate dehydrogenase and pyruvate dehydrogenase complex.

[Pantogam and pantogam active: qualitative and quantitative features of the interaction with neurotransmitter receptors in vitro].

We conducted a comparative study on the effect of active compounds of pantogam and pantogam active (calcium D(R)-homopantothenate and calcium DL(RS)-homopantothenate) and its L(S)-isomer on the receptors of main brain neuromediators in rats using in vitro radioligand binding analysis. All three compounds interact with binding sites of specific GABA-A and, in particular, GABA-B receptor ligands. Racemate and S-enantiomer, but not its R-form, competed to a moderate degree for D2-receptor binding sites. In all cases, degrees of interaction with receptors were ranged as follows: S-isomer>racemate>R-isomer. These qualitative and quantitative differences are assumed to contribute to pharmacological activity of both drugs.

Panthenyl triacetate transformation, stimulation of metabolic pathways, and wound-healing properties in the human skin.

Vitamin B5 and its derivatives are well known in personal care applications and are often used in wound healing and soothing compositions. However, little is known about the biochemical pathways involved. A better knowledge of these pathways would help to understand some of the mechanisms of action and suggest further applications. We have investigated the transformation of D-panthenyl triacetate (PTA) into D-panthenol (PAN) and its skin diffusion on human volunteers by Raman spectroscopy. Additionally, we have utilized human skin biopsies and quantitative RT-PCR to demonstrate the effect of PTA compared to PAN on 27 metabolic markers when introduced at 2% in a cosmetic emulsion. Then we conducted a double-blind clinical study to measure the effect of PTA compared to PAN on wound healing, measured by transepidermal water loss (TEWL), when incorporated at 3% in a cosmetic emulsion. Results show de-acetylation of PTA into PAN and an increased activity of PTA compared to PNA over time in the skin. Metabolic marker analysis demonstrates stimulation of energetic pathways such as glycolysis and the citric acid cycle, but also of synthesis pathways such as isoprenoids and lipid synthesis, by PTA and PAN. Finally, the clinical study demonstrates a statistically significant effect by PTA on wound healing after 72 hours when compared to a saline treatment. Statistical significance was not achieved by PAN or a placebo treatment. Due to the differences between PTA and PAN action, different applications in personal care products can be suggested. Moreover, PTA seems more effective than PAN for a long-lasting wound healing action.

[Pharmacokinetics of hopantenic acid upon peroral administration].

A simple, specific and sensitive RP-HPLC method with UV detection for the determination of hopantenic acid in human blood plasma has been developed. The pharmacokinetics of drug pantocalcin upon single peroral administration was investigated on 18 healthy volunteers. The peak of hopantenic acid in blood plasma was achieved at 1.56 h and the elimination half life was 6.68 h. No hopantenic acid in blood plasma is found in 48 h.

Bioavailability and antioxidant effects of a xanthone-rich Mangosteen (Garcinia mangostana) product in humans.

Oxidative damage is involved in many chronic diseases including those cited as the major causes of death in Western societies such as cardiovascular disorders and cancer. Antioxidants may prevent these degenerative processes by various mechanisms including the scavenging of free radicals. Intake of antioxidant supplements is associated with preventing oxidative damages. This study investigated the absorption and antioxidant effects of a xanthone-rich mangosteen liquid in healthy human volunteers after the acute consumption of 59 mL of the supplement. The liquid contained mangosteen, aloe vera, green tea, and multivitamins. Results indicated that alpha-mangostin and vitamins B(2) and B(5) were bioavailable, with observed C(max) at t(max) of around 1 h. The antioxidant capacity measured with the oxygen radical absorbance capacity (ORAC) assay was increased with a maximum effect of 18% after 2 h, and the increased antioxidant level lasted at least 4 h. Overall, this study demonstrated the bioavailability of antioxidants from a xanthone-rich mangosteen product and its in vivo antioxidant effects.

The human malaria parasite Plasmodium falciparum is not dependent on host coenzyme A biosynthesis.

Pantothenate, a precursor of the fundamental enzyme cofactor coenzyme A (CoA), is essential for growth of the intraerythrocytic stage of human and avian malaria parasites. Avian malaria parasites have been reported to be incapable of de novo CoA synthesis and instead salvage CoA from the host erythrocyte; hence, pantothenate is required for CoA biosynthesis within the host cell and not the parasite itself. Whether the same is true of the intraerythrocytic stage of the human malaria parasite, Plasmodium falciparum, remained to be established. In this study we investigated the metabolic fate of [(14)C]pantothenate within uninfected and P. falciparum-infected human erythrocytes. We provide evidence consistent with normal human erythrocytes, unlike rat erythrocytes (which have been reported to possess an incomplete CoA biosynthesis pathway), being capable of CoA biosynthesis from pantothenate. We also show that CoA biosynthesis is substantially higher in P. falciparum-infected erythrocytes and that P. falciparum, unlike its avian counterpart, generates most of the CoA synthesized in the infected erythrocyte, presumably necessitated by insufficient CoA biosynthesis in the host erythrocyte. Our data raise the possibility that malaria parasites rationalize their biosynthetic activity depending on the capacity of their host cell to synthesize the metabolites they require.

Biotin uptake by human colonic epithelial NCM460 cells: a carrier-mediated process shared with pantothenic acid.

Previous studies showed that the normal microflora of the large intestine synthesizes biotin and that the colon is capable of absorbing intraluminally introduced free biotin. Nothing, however, is known about the mechanism of biotin absorption in the large intestine and its regulation. To address these issues, we used the human-derived, nontransformed colonic epithelial cell line NCM460. The initial rate of biotin uptake was found to be 1) temperature and energy dependent, 2) Na+ dependent (coupling ratio of 1:1), 3) saturable as a function of concentration [apparent Michaelis constant (Km) of 19.7 microM], 4) inhibited by structural analogs with a free carboxyl group at the valeric acid moiety, and 5) competitively inhibited by the vitamin pantothenic acid (inhibition constant of 14.4 microM). Pretreatment with the protein kinase C (PKC) activators phorbol 12-myristate 13-acetate (PMA) and 1, 2-dioctanoyl-sn-glycerol significantly inhibited biotin uptake. In contrast, pretreatment with the PKC inhibitors staurosporine and chelerythrine led to a slight, but significant, increase in biotin uptake. The effect of PMA was mediated via a marked decrease in maximal uptake velocity and a slight increase in apparent Km. Pretreatment of cells with modulators of the protein kinase A-mediated pathway, on the other hand, showed no significant effect on biotin uptake. These results demonstrate, for the first time, the functional existence of a Na+-dependent, specialized carrier-mediated system for biotin uptake in colonic epithelial cells. This system is shared with pantothenic acid and appears to be under the regulation of an intracellular PKC-mediated pathway.

Cloning and functional expression of a cDNA encoding a mammalian sodium-dependent vitamin transporter mediating the uptake of pantothenate, biotin, and lipoate.

Previous studies have shown that a Na+-dependent transport system is responsible for the transplacental transfer of the vitamins pantothenate and biotin and the essential metabolite lipoate. We now report the isolation of a rat placental cDNA encoding a transport protein responsible for this function. The cloned cDNA, when expressed in HeLa cells, induces Na+-dependent pantothenate and biotin transport activities. The transporter is specific for pantothenate, biotin, and lipoate. The Michaelis-Menten constant (Kt) for the transport of pantothenate and biotin in cDNA-transfected cells is 4.9 +/- 1.1 and 15.1 +/- 1.2 microM, respectively. The transport of both vitamins in cDNA-transfected cells is inhibited by lipoate with an inhibition constant (Ki) of approximately 5 microM. The nucleotide sequence of the cDNA (sodium-dependent multivitamin transporter (SMVT)) predicts a protein of 68.6 kDa with 634 amino acids and 12 potential transmembrane domains. Protein data base search indicates significant sequence similarity between SMVT and known members of the Na+-dependent glucose transporter family. Northern blot analysis shows that SMVT transcripts are present in all of the tissues that were tested. The size of the principal transcript is 3.2 kilobases. SMVT represents the first Na+-dependent vitamin transporter to be cloned from a mammalian tissue.

[A comparative study of the permeability across the hemato-encephalic barrier and of the effect on cerebral blood flow of the new neurotropic agent calcium ketohomopantothenate and of pantogam]. / Sravnitel'noe issledovanie pronitsaemosti cherez gematoéntsefalicheskii ba'er i vliianiia na mozgovoi krovotok novogo neirotropnogo sredstva--ketogomopantotenata kal'tsiia i pantogama.

The permeability through the blood-brain barrier of N-(4-hydroxy-3,3 dimethyl-2-oxo-1-butiryl) gamma-aminobutyric acid calcium salt, a new neurotropic drug calcium ketohomopantothenate (KPA-Ca), was studied in comparison with that of calcium homopantothenate, pantogam (P) Liquid chromatography analysis showed that after oral administration of KPA-Ca and P both forms of these agents, namely, oxy- and keto- derivatives of homopantothenic acid, were found in the brain of experimental rats, the KPA-Ca (ketoform) content being higher. Pharmacological studies showed that KPA-Ca penetrates the blood-brain barrier in greater amounts and causes a higher effect on the rate of cerebral blood flow when it is administered per os in a dose of 50 mg/kg.

Niacin, thiamin, and pantothenic acid bioavailability to humans from maize bran as affected by milling and particle size.

The objective of the project was to determine the bioavailability of selected B vitamins (niacin, pantothenic acid and thiamin) to humans from wet and dry milled maize brans which were coarsely or finely ground. Using a double cross-over design, the nine subjects were fed laboratory controlled diets containing unsupplemented bread or bread supplemented with finely ground, wet milled maize bran; coarsely ground, wet milled maize bran; finely ground, dry milled corn bran; or coarsely ground, dry milled maize bran. Subjects made complete collections of urine throughout the study which were analyzed for contents of the test vitamins. Although varying somewhat among vitamins, in general, better apparent bioavailability was achieved with the finely ground, dry milled maize bran than with the other test brans.

Pantothenic acid in health and disease.

In summary, the vitamin pantothenic acid is an integral part of the acylation carriers, CoA and acyl carrier protein (ACP). The vitamin is readily available from diverse dietary sources, a fact which is underscored by the difficulty encountered in attempting to induce pantothenate deficiency. Although pantothenic acid deficiency has not been linked with any particular disease, deficiency of the vitamin results in generalized malaise clinically. In view of the fact that pantothenate is required for the synthesis of CoA, it is surprising that tissue CoA levels are not altered in pantothenate deficiency. This suggests that the cell is equipped to conserve its pantothenate content, possibly by a recycling mechanism for utilizing pantothenate obtained from degradation of pantothenate-containing molecules. Although the steps involved in the conversion of pantothenate to CoA have been characterized, much remains to be done to understand the regulation of CoA synthesis. In particular, in view of what is known about the in vitro regulation of pantothenate kinase, it is surprising that the enzyme is active in vivo, since factors that are known to inhibit the enzyme are present in excess of the concentrations known to inhibit the enzyme. Thus, other physiological regulatory factors (which are largely unknown) must counteract the effects of these inhibitors, since the pantothenate-to-CoA conversion is operative in vivo. Another step in the biosynthetic pathway that may be rate limiting is the conversion of 4'-phosphopantetheine (4'-PP) to dephospho-CoA, a step catalyzed by 4'-phosphopantetheine adenylyl-transferase. In mammalian systems, this step may occur in the mitochondria or in the cytosol. The teleological significance of these two pathways remains to be established, particularly since mitochondria are capable of transporting CoA from the cytosol. Altered homeostasis of CoA has been observed in diverse disease states including starvation, diabetes, alcoholism, Reye syndrome (RS), medium-chain acyl CoA dehydrogenase deficiency, vitamin B12 deficiency, and certain tumors. Hormones, such as glucocorticoids, insulin, and glucagon, as well as drugs, such as clofibrate, also affect tissue CoA levels. It is not known whether the abnormal metabolism observed in these conditions is the result of altered CoA metabolism or whether CoA levels change in response to hormonal or nonhormonal perturbations brought about in these conditions. In other words, a cause-effect relation remains to be elucidated. It is also not known whether the altered CoA metabolism (be it cause or result of abnormal metabolism) can be implicated in the manifestations of a disease. Besides CoA, pantothenic acid is also an integral part of the ACP molecule.(ABSTRACT TRUNCATED AT 400 WORDS)

[The metabolism of panthenol in patients with postoperative intestinal atony]. / Untersuchungen über den Metabolismus von Panthenol bei Patienten mit postoperativer Darmatonie.

The aim of this study was the examination of the metabolism and mechanism of action of D-pantothenyl alcohol in patients with postoperative intestinal atony. Seven metabolically healthy patients were examined on the 4th day following colorectal surgery, before bowel activity had started. Increased urinary excretion of the vitamin pantothenic acid was noted following the intravenous application of 2 gm of D-pantothenyl alcohol. Ten to 30% of the administered dose D-pantothenyl alcohol is excreted in the urine as pantothenic acid within 24 h. Simultaneously, the urinary excretion of beta-alanine, a pantothenic acid component, is increased. D-pantothenyl alcohol was metabolized to pantothenic acid in all the patients examined. Pantothenic acid is a component of coenzyme A, a key substance in the intermediary pathway of metabolism. Coenzyme A plays a role in the synthesis of acetylcholine from choline (a co-enzyme of cholinacetylase). Peristalsis induced by D-pantothenyl alcohol may be due to the increased synthesis of coenzyme A and acetylcholine in the autonomic nerve plexus of the intestinal tract.

[Distribution and biotransformation of labelled pantothenate in cytoplasmic and mitochondrial fractions of the rat liver with a deficiency of pantothenic acid]. / Raspredelenie i biotransformatsiia mechenogo pantotenata v tsitoplazmaticheskoi i mitokhondrial'noi fraktsii pecheni krys s nedostatochnost'iu pantotenovoi kisloty.

Experiments were conducted on white rats given synthetic rations devoid of pantothenic acid during 10 weeks. Intensification of 14C-pantothenate deposition was recorded 30 min and 4 h after its intraperitoneal administration. The mitochondrial fraction of the liver accumulated the isotope in time. High-performance liquid chromatography used for separation of the vitamin labeled metabolites has revealed phosphopantothenate (pantothenate), phosphopantothein, CoA and dephospho-CoA (pantetein) in the liver homogenate, while in the mitochondria extracts only CoA and dephospho-CoA (pantetein) were detected. It has been suggested that dephosphorylation of pantothenate metabolites and rapid transformation of phosphopantetein into CoA may take place during the separation of the fractions.