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PubMed2000

Magnetic resonance spectroscopy (MRS) in five patients with treated propionic acidemia.

Propionic acidemia is an inherited disorder caused by a defect of propionyl CoA carboxylase. Untreated, propionic acidemia leads to metabolic decompensation and toxic encephalopathy. We report on the magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) findings in five children who were properly treated by protein restriction and carnitine supplementation, during a phase of clinically and metabolically stable conditions. The examinations were performed on a whole-body 1.5 T scanner. During the observation period, from 1992 to 1996 we employed long echo time single-voxel spectroscopy and chemical shift imaging in addition to a conventional MRI protocol. The two children with the longest delay before onset of therapy showed cerebral atrophy. MRS yielded elevated lactate peaks in four of the children. These results indicate that MRS can detect metabolic alterations in the brains of children with propionic acidemia during metabolically stable conditions. The presence of lactate could be caused by hampered aerobic oxidation within the citrate cycle due to intracellular elevated propionic metabolites.

Amino Acid Metabolism, Inborn Errors↗
PubMed1996

3-(3,5-Dimethyl-4-octadecanoylpyrrol-2-yl)propionic acids as inhibitors of 85 kDa cytosolic phospholipase A2.

3-(1,4-Diacylpyrrol-2-yl)propionic acids were designed as inhibitors of cytosolic phospholipase A2. Enzyme inhibition was assayed by evaluation of calcium ionophore A23187-induced arachidonic acid release from bovine platelets. While the synthesized bisacyl compound 3-[3,5-dimethyl-4-octadecanoyl-1-(3-phenylpropionyl)pyrrol-2-yl] propionic acid was inactive at 33 microM, the related monoacylated 3-(3,5-dimethyl-4-octadecanoylpyrrol-2-yl)-propionic acid and 3-(1,3,5-trimethyl-4-octadecanoylpyrrol-2-yl)-propionic acid proved to be inhibitors of cytosolic phospholipase A2(IC50: 24 microM and 13 microM, respectively).

Animals↗
PubMed1976

Inhibition of acetate and propionate formation upon aeration of resting cells of the anaerobic Propionibacterium shermanii: evidence of the Pasteur reaction.

When resting cell suspensions of the anaerobic P. shermanii were brought to an oxygen concentration of 0.64 mumoles/ml, acid formation was completely inhibited. The cells started to respire on the propionic acid previously accumulated furing anaerobiosis. Glucose consumption was concomitantly decreased to about 60 percent of the rate during anaerobiosis. As the viability of the cells was not affected by the transition to aerobic conditions, the changes observed upon aeration were ascribed to the regulatory properties of the Pasteur reaction. Damage inflicted by oxygen was encountered in the rapid inactivation of propionate respiration. This damage outlived the time of oxygenation, and was manifested during the subsequent anaerobiosis in the decreased activity to form propionate. This indicates that oxygen may inactivate one (or more) enzyme(s) involved in the metabolism of propionate. The viability of cells in buffer, and glucose-containing buffer, was found to be only insignificantly decreased by oxygen in the range from 0 to 500 mumoles of oxygen per g of wet cells.

Acetates↗
PubMed1997

In vitro phosphorylation of cytoskeletal proteins in the rat cerebral cortex is decreased by propionic acid.

In the present study we demonstrate that propionic acid (PA), a metabolite that accumulates in large amounts in propionic acidemia, is able to decrease in vitro incorporation of [32P]ATP into neurofilament subunits (NF-M and NF-L) and alpha- and beta-tubulin. Considering that the endogenous phosphorylating system associated with the cytoskeletal fraction contains cAMP-dependent protein kinase (PKA), Ca2+/calmodulin protein kinase II (CaMKII), and protein phosphatase 1 (PP1), we first assayed the effect of the acid on the kinase activities by using the specific activators cAMP and Ca2+/calmodulin or the inhibitors PKAI or KN-93 for PKA and CaMKII, respectively. Results demonstrated that the acid totally inhibited the stimulatory effect of cAMP and interfered with the inhibitory effect of PKAI. In addition, PA partially prevented the stimulatory effect of Ca2+/calmodulin and interfered with the effect of KN-93. In addition, we demonstrated that PA totally inhibited in vitro dephosphorylation of neurofilament subunits and tubulins mediated by PP1 in brain slices pretreated with the acid. Taken together, these results demonstrate that PA inhibits the in vitro activities of PKA, CaMKII, and PP1 associated with the cytoskeletal fraction of the cerebral cortex of rats. This study suggests that PA at the same concentrations found in tissues from propionic acidemic children may alter phosphorylation of cytoskeletal proteins, which may contribute to the neurological dysfunction characteristic of propionic acidemia.

Animals↗
PubMed1996

Propionylcarnitine excretion is not affected by metronidazole administration to patients with disorders of propionate metabolism.

UNLABELLED: Propionylcarnitine (PC) excretion has been measured during a clinical trial of metronidazole therapy in two patients with propionic acidaemia and two patients with methylmalonic aciduria. All patients were in good metabolic control and were receiving L-carnitine. While total propionate excretion was reduced by up to 40% in all four patients during metronidazole therapy, the excretion of propionylcarnitine remained largely unchanged. PC comprised up to 80% of total propionate excretion in patients with propionic acidaemia. CONCLUSION: These results suggest an extra-hepatic source and/or differing compartmentation for PC formation from those for the production of other metabolites of propionyl-CoA.

Amino Acid Metabolism, Inborn Errors↗
PubMed1994

Propionic acidaemia: clinical, biochemical and therapeutic aspects. Experience in 30 patients.

Comprehensive data on 30 patients with propionic acidaemia, diagnosed by selective screening for inborn errors of metabolism, are presented. The most valuable diagnostic metabolites found were methylcitric-, 3-hydroxypropionic-, and 2-methyl-3-oxovaleric acids. Hyperlysinaemia and hyperlysinuria are also characteristic findings in this disease. The metabolic pattern found in propionic acidaemia is discussed extensively as are enzymatic findings. Residual activity of propionyl-CoA carboxylase is neither a predictive marker for severity nor for outcome of the disease. Propionate fixation assays were less reliable for confirmation of propionic acidaemia and of no prognostic value. Clinical presentation of the disease is discussed in detail. Besides the well-known unspecific findings (poor appetite, feeding difficulties, vomiting, dehydration, weight loss, muscular hypotonia, dyspnoea, somnolence, apathy, convulsion, coma, severe metabolic acidosis, hyperammonaemia) various skin abnormalities have been detected in about 50% of all patients. In 27% "dermatitis acidemica" was found.

Amino Acid Metabolism, Inborn Errors↗
PubMed1988

Propionate and the production of monensins in Streptomyces cinnamonensis.

Variants resistant to propionate were prepared from a mutant strain of Streptomyces cinnamonensis producing predominantly monensin A. Using selected resistants the production of monensins (in media with higher concentrations of propionate) was examined. Stimulation of monensin synthesis by propionate was observed with 70% of the resistants studied. Propionate did not influence the ratio between monensin A and B production.

Drug Resistance, Microbial↗
PubMed2005

The effect of short-chain fatty acids butyrate, propionate, and acetate on urothelial cell kinetics in vitro: potential therapy in augmentation cystoplasty.

The intestinal element of enterocystoplasty is affected by chronic inflammatory changes, which lead to excess mucus production, urinary tract infections, and stone formation. There is also an increased risk of malignancy. These inflammatory changes may be due to diversion colitis, which affects colonic segments excluded from the faecal stream and likewise may respond to intraluminal short-chain fatty acid (SCFA) therapy. The SCFAs have interesting antiproliferative, differentiating, and pro-apoptotic effects, which are protective against colorectal cancer and may influence the risk of malignancy in enterocystoplasty. Before intravesical therapy can be considered, the effect on normal urothelium must be investigated. Primary urothelial cells cultured from biopsy specimens and transformed urothelial (RT112 and MGH-U1) and intestinal cell lines (HT29 and CaCo-2) were incubated with SCFAs. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to measure the residual viable biomass to assess cell proliferation. Proliferation of primary and transformed urothelial cells in culture was inhibited by all SCFAs in a similar time- and dose-dependent manner. The concentration of SCFA required to inhibit growth of primary cells by 50% (IC50) was 20 mM of butyrate, 120 mM of propionate, and 240 mM of acetate after incubation for 1 h. After 72 h the IC50 was 2 mM of butyrate, 4 mM of propionate, and 20 mM of acetate. Transformed urothelial and colon cancer cell lines demonstrated similar growth inhibition. Butyrate was the most potent inhibitor of cell proliferation, followed by propionate and then acetate. Growth inhibition is not an immediate cytotoxic effect, and urothelial cells show a degree of adaptation to butyrate and growth recovery after incubation with butyrate. In conclusion, butyrate- and propionate-induced growth inhibition is potentially clinically significant and may have therapeutically beneficial implications in vivo.

Acetates↗
PubMedDate not supplied

'Classical' organic acidurias, propionic aciduria, methylmalonic aciduria and isovaleric aciduria: long-term outcome and effects of expanded newborn screening using tandem mass spectrometry.

'Classical organic acidurias' comprise isovaleric aciduria, propionic aciduria and methylmalonic aciduria. Available data from the literature suggest that the use of 'new' therapeutic strategies has improved survival but has not modified neurodevelopment. Progressive neurocognitive deterioration is almost invariably present in propionic and methylmalonic acidurias, while large-scale studies on the long-term outcome of patients with isovaleric aciduria are still lacking. In order to answer to some of the questions suggested by Wilson and Jungner in 1968 about the criteria of disease screening, we compared the natural history of patients with 'classical' organic acidurias diagnosed on clinical bases to those diagnosed through neonatal mass screening using tandem mass spectrometry. Decreased early mortality, less severe symptoms at diagnosis, and more favourable short-term neurodevelopmental outcome were recorded in patients identified through expanded newborn screening. The short duration of follow-up so far does not allow us to draw final conclusions about the effects of newborn screening on long-term outcome. The evaluation of the effect of neonatal screening on the detection rate of these three diseases showed that the incidence of isovaleric aciduria was significantly higher in the screening population than in clinically detected cases, with no changes for propionic and methylmalonic acidurias. Further multicentre longitudinal studies are needed to assess the usefulness of expanded newborn screening for 'classical' organic acidurias and to better understand the clinical spectrum of these diseases. This paper describes the long-term outcome and the impact of expanded newborn screening on the so-called 'classical' organic acidurias (propionic aciduria, methylmalonic aciduria and isovaleric aciduria).

Amino Acid Metabolism, Inborn Errors↗
PubMedDate not supplied

Gluconeogenesis from propionate produced in the colon of the horse.

The production of propionate has been measured in the large colon of two ponies fitted with cannulas and fed on a standard diet of hay or hay and wheat bran. A continuous infusion of 14C-labelled sodium propionate was made into a cannula in the right ventral colon and samples of ingesta were obtained from another cannula near the end of the right dorsal colon. A simultaneous intravenous infusion of [2-3H]-labelled glucose was made to measure total glucose entry. Colonic propionate production on the hay diet was 146 (range 110-176) mg/h per kg body weight and, on the hay and bran, 195 (range 130-273) mg/h per kg body weight. Mean total glucose production for the two diets was 120 (range 98-143) and 92 (range 79-116) mg/h per kg body weight, respectively. The results obtained indicate that 50% of the glucose was synthesized from propionate produced in the colon in ponies on the hay diet and 61% in ponies on the hay and bran diet.

Animals↗
PubMed1980

Isotope dilution analysis of methylcitric acid in amniotic fluid for the prenatal diagnosis of propionic and methylmalonic acidemia.

A stable isotope dilution assay for methylcitric acid in amniotic fluid was developed to provide rapid prenatal diagnosis of the inherited disorders propionic acidemia and methylmalonic acidemia. The method utilizes two 2H3-labeled diastereoisomers of methylcitric acid as internal standards, isolation by liquid partition chromatography and quantitation of the trimethyl esters by chemical ionization selected ion monitoring gas chromatography-mass spectrometry. Methylcitric acid at a concentration of 0.38 +/- 0.10 mumol/l was detected in normal amniotic fluid. Highly elevated levels of 7.87 and 9.16 mumol were found in the fluids surrounding fetuses affected with propionic acidemia and levels of 1.79, 2.72 and 12.27 mumol were found for fetuses with methylmalonic acidemia. Methylcitric acid was not elevated in the amniotic fluid of a fetus heterozygous for propionic acidemia. In the five pregnancies at risk for propionic acidemia, and three pregnancies at risk for methylmalonic acidemia, the levels of methylcitric acid in amniotic fluid gave the diagnosis in all cases. Measurement of methylcitric acid in amniotic fluid therefore provides a rapid and reliable method for the prenatal diagnosis of these genetic disorders.

Amino Acid Metabolism, Inborn Errors↗
PubMed1988

Bisfunction of propionic acid on purified rat liver beta-ureidopropionase.

Propionic acid and isobutyric acid, which are structural analogues of N-carbamoyl-beta-alanine and N-carbamoyl-beta-aminoisobutyric acid, respectively, acted as an allosteric activator as well as a competitive inhibitor of purified rat liver beta-ureidopropionase. Propionic acid and isobutyric acid had a Ki value of approx. 0.3 mM at pH 7.0. The Hill coefficient for N-carbamoyl-beta-alanine was 2.0, but the cooperatively decreased to 1.0 in the presence of 1 mM propionic acid. The K1/2 value towards N-carbamoyl-beta-alanine was calculated to be 0.17 mM from Hill plots and the Km value was determined to be 0.06 mM from replots of the apparent Km vs propionic acid.

Amidohydrolases↗
PubMed1990

Effect of propionate on the utilization of nitrogen from 15NH4Cl for urea synthesis in hepatocytes isolated from sheep liver.

1. The effect of ornithine (2.0 mM) and propionate (5.0 mM) on the utilization of N from 15NH4Cl (5.0 mM) for urea synthesis in hepatocytes isolated from sheep liver was investigated. 2. The capacity of sheep hepatocytes to utilize [15N]ammonia in the absence of the other exogenous substrates was very low and amounted 132 +/- 37.3 mumol/hr per 1 g dry wt. 3. Ornithine failed to affect the total [15N]ammonia uptake and total urea synthesis, but at the same time it markedly increased the utilization of [15N]ammonia for ureagenesis and diminished the rate of urea synthesis from endogenous sources. 4. Propionate markedly increased total [15N]ammonia utilization and total urea formation; this increase resulted from the rise of ammonia utilization for urea synthesis and it was similar in the presence or absence of ornithine. 5. The capacity of sheep liver cells to utilize ammonia in the presence of propionate (in the presence or absence of ornithine) amounted to 256 mumol/hr per 1 g dry wt, thus being similar to the values in vivo. 6. It is concluded that in sheep hepatocytes both ornithine and propionate stimulate the utilization of ammonia for urea synthesis and these effects take place independently and occur by different mechanisms.

Ammonium Chloride↗
PubMed1993

Satiety signals in sheep: involvement of CCK, propionate, and vagal CCK binding sites.

The satiety effects of the hormone, cholecystokinin (CCK), and propionate, an important gluconeogenic substrate, were studied in ad lib-fed sheep. Hepatic portal infusion of either sodium propionate (1.2 mmol/min) or sulphated CCK-8 (sCCK-8; 18.3 pmol/kg/min) had no effect on food intake. However, together, they decreased intake by 44%; similar to the effect of 2.4 mmol/min propionate alone. CCK infusions reduced the frequency of reticular contractions in the presence or absence of propionate. The effects of infusions on motility and food intake were, therefore, dissociated. Further studies demonstrated axonal transport of CCK binding sites in the ovine vagus. Binding sites accumulated to a similar extent on both sides of a ligature indicating the existence of both anterograde and retrograde transport which was limited to a small proportion of fibres. Binding incubations carried out in the presence of the CCK receptor antagonists, MK-329 and L-365,260, indicated that the majority of binding sites, if not the total population, possessed pharmacology typical of type B CCK receptors.

Animals↗
PubMed1993

Biosynthesis of poly(3-hydroxy-alkanoates) in Pseudomonas aeruginosa AO-232 from 13C-labelled acetate and propionate.

Pseudomonas aeruginosa AO-232 produced poly(3-hydroxyalkanoates) (P(3HA)) containing monomer units of even carbon numbers C6, C8, C10 and C12, when sodium acetate was fed as the sole carbon source. In contrast, the P(3HA) produced from sodium propionate was composed of seven different 3HA units ranging from C6 to C12. The pathways of P(3HA) synthesis were investigated by using 13C-labelled acetate and propionate as the carbon sources. The 13C-labelled carbonyl carbon of [1-13C] acetate was selectively incorporated into the odd-numbered carbon atoms of 3HA units, while the methyl carbon of [2-13C] acetate was introduced into the even-numbered carbon atoms of 3HA units. The 13C-labelled carbonyl carbon of [1-13C] propionate was selectively incorporated into the third carbon atoms from methyl carbons in the 3HA units of C7, C9 and C11. The synthesis of P(3HA) from acetate or propionate was related to de novo fatty acid biosynthesis.

Acetates↗
PubMed1992

Effects of propionate on the acid microclimate of hen (Gallus domesticus) colonic mucosa.

1. Short-chain fatty acid absorption in hen colon is protonated across the apical border coupled to an apical electrogenic proton pump. 2. The surface pH of the isolated colonic epithelium was 6.27 +/- 0.05, when incubated in Krebs-phosphate buffer pH 7.0. 3. Propionate 7 and 40 mmol/l in the incubation medium (pH 7.0) increased microclimate pH to 6.47 +/- 0.04 and 6.56 +/- 0.04. Inhibition of metabolic activity by potassium cyanide 1 mmol/l increased surface pH to 6.66 +/- 0.06. 4. The calculated concentration of propionic acid in the microclimate is near-linearly related to the propionate concentration. Thus, the acid microclimate is not responsible for the Michaelis-Menten like kinetics of propionate transport.

Animals↗
PubMed1986

Propionate metabolism and its regulation by fatty acids in ovine hepatocytes.

Propionate metabolism was studied in ovine hepatocytes. The main products of metabolism were CO2, glucose, L-lactate and pyruvate. The fatty acids, butyrate and palmitate inhibited propionate oxidation; butyrate inhibited but palmitate slightly stimulated gluconeogenesis from propionate. Butyrate and palmitate also inhibited lactate and pyruvate production from both endogenous substrates and from propionate.

Animals↗
PubMed2005

Synthetic modification of the 2-oxypropionic acid moiety in 2-{4-[(7-chloro-2-quinoxalinyl)oxy]phenoxy}propionic acid (XK469), and consequent antitumor effects. Part 4.

The criteria for the activity of 2-{4-[(7-chloro-2-quinoxalinyl)oxy]phenoxy}propionic acid (XK469) and 2-{4-[(7-bromo-2-quinolinyl)oxy]phenoxy}propionic acid (SH80) against transplanted tumors in mice established in previous studies, require a (7-halo-2-quinoxalinoxy)- or a (7-halo-2-quinolinoxyl)-residue, respectively, bridged via a 1,4-OC(6)H(4)O-linker to C(2) of propionic acid. The present work demonstrates that substitution of fluorine at the 3-position of the 1,4-OC(6)H(4)O-linker of XK469 leads to a 10-fold reduction in activity, whereas the corresponding 2-fluoro analog proved to be 100-fold less active than XK469. Moreover, the latter tolerated substitution of but a single, additional methyl group to the 2-position of the propionic acid moiety, that is, the isobutyric acid analog, without loss of significant in vivo activity. Indeed, an intact 2-oxypropionic acid moiety is a prerequisite for maximum antitumor activity of 1a.

Animals↗