Prescription patterns of analgesics in cancer patients with bone metastases in Japan: a retrospective database study.

BACKGROUND: Real-world data on optimal cancer pain management remain scarce. We describe prescription patterns of analgesics in Japanese cancer patients with bone metastases. METHODS: National hospital-based claims data were analyzed. Adults with first diagnosis of cancer during 2015-2019 and first diagnosis of bone metastasis after the initial cancer diagnosis were included. Skeletal-related events (SREs) were identified with disease and receipt codes. RESULTS: Among the 40,507 eligible patients (age [mean ± SD], 69.7 ± 11.7 years), lung (25.3%), prostate (15.6%), breast (10.9%), and colorectal (10.7%) cancers were common primary tumors. Time (mean ± SD) between primary cancer diagnosis and bone metastases was 306.9 ± 490.4 days; median survival time from bone metastases was 483.0 days. Most patients used acetaminophen (62.7%, 117.5 days/year) and nonsteroidal anti-inflammatory drugs (NSAIDs; 75.3%, 170.0 days/year). Commonly used opioids included oxycodone (39.4%; 479.3 days/year), fentanyl (32.5%; 52.6 days/year), morphine (22.1%; 130.9 days/year), and tramadol (15.3%; 143.0 days/year). Internal medicine, surgery, respiratory, urology, and orthopedics treated 19.4%, 18.5%, 17.6%, 17.3%, and 13.0% of patients, respectively. Prescription patterns varied inter-department. Overall, 44.9% of patients developed SRE (bone pain requiring radiation [39.6%] or orthopedic surgery [2.9%]; hypercalcemia, 4.9%; pathological fracture, 3.3%; spinal cord compression, 0.4%). Analgesics use by patients with SREs was 1.8- to 2.2-fold in the postsymptomatic vs the presymptomatic period. SRE patients had numerically lower survival probabilities than non-SRE patients. Opioid use increased considerably in the month before death. CONCLUSION: In Japanese cancer patients with bone metastases, acetaminophen, NSAIDs, and weak or strong opioids were commonly used; their use increased after SREs developed. Opioid use increased closer to death.

Polyamine stimulation of eEF1A synthesis based on the unusual position of a complementary sequence to 18S rRNA in eEF1A mRNA.

It is thought that Shine-Dalgarno-like sequences, which exhibit complementarity to the nucleotide sequences at the 3'-end of 18S rRNA, are not present in eukaryotic mRNAs. However, complementary sequences consisting of more than 5 nucleotides to the 3'-end of 18S rRNA, i.e., a CR sequence, are present at -17 to -32 upstream from the initiation codon AUG in 18 mRNAs involved in protein synthesis except eEF1A mRNA. Thus, effects of the CR sequence in mRNAs and polyamines on protein synthesis were examined using control and polyamine-reduced FM3A and NIH3T3 cells. Polyamines did not stimulate protein synthesis encoded by 18 mRNAs possessing a normal CR sequence. When the CR sequence was deleted, protein synthetic activities decreased to less than 70% of intact mRNAs. In eEF1A mRNA, the CR sequence was located at -33 to -39 upstream from the initiation codon AUG, and polyamines stimulated eEF1A synthesis about threefold. When the CR sequence was shifted to -22 to -28 upstream from the AUG, eEF1A synthesis increased in polyamine-reduced cells and the degree of polyamine stimulation decreased greatly. The results indicate that the CR sequence exists in many eukaryotic mRNAs, and the location of a CR sequence in mRNAs influences polyamine stimulation of protein synthesis.

Excess of de novo deleterious mutations in genes associated with glutamatergic systems in nonsyndromic intellectual disability.

Little is known about the genetics of nonsyndromic intellectual disability (NSID). We hypothesized that de novo mutations (DNMs) in synaptic genes explain an important fraction of sporadic NSID cases. In order to investigate this possibility, we sequenced 197 genes encoding glutamate receptors and a large subset of their known interacting proteins in 95 sporadic cases of NSID. We found 11 DNMs, including ten potentially deleterious mutations (three nonsense, two splicing, one frameshift, four missense) and one neutral mutation (silent) in eight different genes. Calculation of point-substitution DNM rates per functional and neutral site showed significant excess of functional DNMs compared to neutral ones. De novo truncating and/or splicing mutations in SYNGAP1, STXBP1, and SHANK3 were found in six patients and are likely to be pathogenic. De novo missense mutations were found in KIF1A, GRIN1, CACNG2, and EPB41L1. Functional studies showed that all these missense mutations affect protein function in cell culture systems, suggesting that they may be pathogenic. Sequencing these four genes in 50 additional sporadic cases of NSID identified a second DNM in GRIN1 (c.1679_1681dup/p.Ser560dup). This mutation also affects protein function, consistent with structural predictions. None of these mutations or any other DNMs were identified in these genes in 285 healthy controls. This study highlights the importance of the glutamate receptor complexes in NSID and further supports the role of DNMs in this disorder.

Inactivation of GAPDH as one mechanism of acrolein toxicity.

We have recently reported that acrolein is more toxic than reactive oxygen species. Thus, the mechanism of cell toxicity by acrolein was studied using mouse mammary carcinoma FM3A cells. Acrolein-conjugated proteins were separated by gel electrophoresis with subsequent determination of their amino acid sequence, and it was found that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was one of the major acrolein-conjugated proteins in cells. Acrolein interacted with cysteine-150 at the active site of GAPDH, and also with cysteine-282. When cells were treated with 8 µM acrolein, the activity of acrolein-conjugated GAPDH was greatly reduced, and the ATP content in cells was thus significantly reduced. In addition, it was shown that acrolein-conjugated GAPDH translocated to the nucleus, and the level of acetylated GAPDH and the number of TUNEL positive cells was increased, indicating that cell death is enhanced by acrolein-conjugated GAPDH. Inhibition of cell growth by acrolein was partially reversed when the cDNA encoding GAPDH was transformed into cells. These results indicate that inactivation of GAPDH is one mechanism that underlies cell toxicity caused by acrolein.

Expression, purification, crystallization and preliminary crystallographic analysis of spermidine acetyltransferase from Escherichia coli.

The spermidine acetyltransferase (SAT) from Escherichia coli catalyses the transfer of acetyl groups from acetyl-CoA to spermidine. SAT has been expressed and purified from E. coli. SAT was crystallized by the sitting-drop vapour-diffusion method to obtain a more detailed insight into the molecular mechanism. Preliminary X-ray diffraction studies revealed that the crystals diffracted to 2.5 Å resolution and belonged to the cubic space group P23, with unit-cell parameters a = b = c = 148.7 Å. They contained four molecules per asymmetric unit.

Augmented glutathione synthesis decreases acrolein toxicity.

We have shown recently that acrolein is more strongly involved in cell damage than reactive oxygen species during brain infarction. Thus, we tried to isolate cells with reduced susceptibility to acrolein toxicity to clarify how acrolein is detoxified under cell culture conditions. The IC(50) of acrolein in mouse mammary carcinoma FM3A cells and in neuroblastoma Neuro2a cells was 2.6 and 4.2µM, respectively, but in acrolein toxicity-decreasing FM3A (FM3A-ATD) cells and Neuro2a (Neuro2a-ATD) cells, it was 7.6 and 8.4µM, respectively. In both FM3A-ATD and Neuro2a-ATD cells, the concentration of glutathione (GSH) was increased, so that detoxification occurred through acrolein conjugation with GSH. In FM3A-ATD cells, the level of a rate-limiting enzyme of GSH synthesis, γ-glutamylcysteine ligase catalytic unit (GCLC), was increased through the reactivation of one inactive allele of GCLC genes in FM3A cells. In Neuro2a-ATD cells, phosphorylation of transcription factors (c-Jun and NF-κB) necessary for expression of genes for GCLC and glutathione synthetase (GSHS) involved in GSH synthesis was stimulated, so that transcription of two genes increased in Neuro2a-ATD cells. Phosphorylation of JNK (c-Jun N-terminal kinase), which catalyzes phosphorylation of c-Jun and NF-κB p65, was also increased in Neuro2a-ATD cells, suggesting that activation of JNK kinase is responsible for the increase in GSH. These results support the idea that GSH plays important roles in detoxification of acrolein, because GSH is increased in both FM3A-ATD and Neuro2a-ATD cells.

Structural changes of regulatory domain heterodimer of N-methyl-D-aspartate receptor subunits GluN1 and GluN2B through the binding of spermine and ifenprodil.

Modeling the binding sites for spermine and ifenprodil on the regulatory (R) domains of the N-methyl-D-aspartate receptor GluN1 and GluN2B subunits was carried out after measuring spermine stimulation and ifenprodil inhibition at receptors containing GluN1 and GluN2B R domain mutants. Models were constructed based on the published crystal structure of the GluN1 and GluN2B R domains, which form a heterodimer (Nature 475:249-253, 2011). The experimental results and modeling suggest that a binding site for spermine was formed by the residues near the cleft between the R1 and R2 lobes of the GluN1 R domain (GluN1R) together with residues on the surface of the R2 (C-terminal side) lobe of the GluN2B R domain (GluN2BR). The ifenprodil binding site included residues on the surface of the R1 lobe (N-terminal side) of GluN1R together with residues near the cleft between the R1 and R2 lobes of GluN2BR. It was confirmed using a Western blot analysis that GluN1R and GluN2BR formed a heterodimer. Models of spermine and ifenprodil binding to the heterodimer were constructed. The modeling suggests that an open space between the two R1 lobes of GluN1R and GluN2BR is promoted through spermine binding and that the R1 lobes of GluN1R and GluN2BR approach each other through ifenprodil binding--an effect opposite to that seen with the binding of spermine.

Structure and function of polyamine-amino acid antiporters CadB and PotE in Escherichia coli.

The structure and function of a cadaverine-lysine antiporter CadB and a putrescine-ornithine antiporter PotE in Escherichia coli were evaluated using model structures based on the crystal structure of AdiC, an agmatine-arginine antiporter, and the activities of various CadB and PotE mutants. The central cavity of CadB, containing the substrate binding site, was wider than that of PotE, mirroring the different sizes of cadaverine and putrescine. The size of the central cavity of CadB and PotE was dependent on the angle of transmembrane helix 6 (TM6) against the periplasm. Tyr(73), Tyr(89), Tyr(90), Glu(204), Tyr(235), Asp(303), and Tyr(423) of CadB, and Cys(62), Trp(201), Glu(207), Trp(292), and Tyr(425) of PotE were strongly involved in the antiport activities. In addition, Trp(43), Tyr(57), Tyr(107), Tyr(366), and Tyr(368) of CadB were involved preferentially in cadaverine uptake at neutral pH, while only Tyr(90) of PotE was involved preferentially in putrescine uptake. The results indicate that the central cavity of CadB consists of TMs 2, 3, 6, 7, 8, and 10, and that of PotE consists of TMs 2, 3, 6, and 8. These results also suggest that several amino acid residues are necessary for recognition of cadaverine in the periplasm because the level of cadaverine is much lower than that of putrescine in the periplasm at neutral pH. All the amino acid residues identified as being strongly involved in both the antiport and uptake activities were located on the surface of the transport path consisting of the central cavity and TM12.

Ribosome modulation factor, an important protein for cell viability encoded by the polyamine modulon.

We searched for proteins whose synthesis is enhanced by polyamines at the stationary phase of cell growth using an Escherichia coli polyamine-requiring mutant in which cell viability is greatly decreased by polyamine deficiency. The synthesis of ribosome modulation factor (RMF) was strongly enhanced by polyamines at the level of translation at the stationary phase of cell growth. In rmf mRNA, a Shine-Dalgarno (SD) sequence is located 11 nucleotides upstream of the initiation codon AUG. When the SD sequence was moved to the more common position 8 nucleotides upstream of the initiation codon, the degree of polyamine stimulation was reduced, although the level of RMF synthesis was markedly increased. Polyamine stimulation of RMF synthesis was found to be caused by a selective structural change of the bulged-out region of the initiation site of rmf mRNA. The decrease in cell viability caused by polyamine deficiency was prevented by the addition of a modified rmf gene whose synthesis is not influenced by polyamines. The results indicate that polyamines enhance cell viability of E. coli at least in part by enhancing RMF synthesis.

Identification of acrolein-conjugated protein in plasma of patients with brain infarction.

It is known that the level of protein-conjugated acrolein in plasma is a good marker of chronic renal failure and brain infarction. Thus, studies were carried out to determine which kinds of plasma proteins are conjugated with acrolein. It was found that acrolein was mainly conjugated with albumin. Tandem mass spectrometry analysis demonstrated that Lys-557 and Lys-560, located at the surface of domain III of albumin, were the major sites conjugated with acrolein. This is the first report to identify the amino acid residues in a protein modified by acrolein in vivo. It was found that conjugation of acrolein with albumin contributed to a decrease in the toxicity of acrolein.

Enhancement of the synthesis of RpoE and StpA by polyamines at the level of translation in escherichia coli under heat shock conditions.

Proteins whose synthesis is enhanced by polyamines at the level of translation were identified with a polyamine-requiring mutant cultured in the presence of 0.1% glucose and 0.02% glutamate at 42 degrees C. Polyamines had a greater effect on cell growth at 42 degrees C than at 37 degrees C. At 42 degrees C, the synthesis of RpoE (sigma(24)) and StpA, which are involved in the transcription of a number of heat shock response genes, was stimulated by polyamines at the level of translation. In the rpoE and stpA mRNAs, a Shine-Dalgarno (SD) sequence is located at 13 and 12 nucleotides, respectively, upstream of the initiation codon AUG. When the SD sequences were moved to the more common position 7 nucleotides upstream of the initiation codon AUG, the degree of polyamine stimulation was reduced, although the level of RpoE and StpA synthesis was markedly increased. The mechanism underlying polyamine stimulation of RpoE synthesis was then studied. Polyamine stimulation of RpoE synthesis was reduced by changing the bulged-out structure in the initiation site of rpoE mRNA, although the level of RpoE synthesis increased. A selective structural change of this bulged-out region induced by spermidine at 42 degrees C was observed by circular dichroism. Polyamine stimulation of fMet-tRNA binding to ribosomes at 42 degrees C also disappeared by changing the bulged-out structure in the initiation site of rpoE mRNA. The results suggest that polyamines enhance the synthesis of RpoE by changing the bulged-out structure in the initiation site of rpoE mRNA.

Acrolein toxicity: Comparison with reactive oxygen species.

The toxicity of acrolein was compared with that of reactive oxygen species using a mouse mammary carcinoma FM3A cell culture system. Complete inhibition of cell growth was accomplished with 10 microM acrolein, 100 microM H(2)O(2), and 20 microM H(2)O(2) plus 1mM vitamin C, which produce ()OH, suggesting that toxicity of acrolein is more severe than H(2)O(2) and nearly equal to that of ()OH, when these compounds were added extracellularly. Acrolein toxicity was prevented by N-acetyl-l-cysteine and N-benzylhydroxylamine, and attenuated by putrescine and spermidine. Toxicity of H(2)O(2) was prevented by glutathione peroxidase plus N-acetyl-l-cysteine, pyruvate, catalase, and reduced by polyphenol, and toxicity of ()OH was prevented by glutathione peroxidase plus N-acetyl-l-cysteine, pyruvate, catalase and reduced by N-acetyl-l-cysteine. The results indicate that prevention of cell toxicity by N-acetyl-l-cysteine was more effective with acrolein than with ()OH. Protein and DNA synthesis was damaged primarily by acrolein and reactive oxygen species, respectively.

Binding of spermine and ifenprodil to a purified, soluble regulatory domain of the N-methyl-D-aspartate receptor.

The binding of spermine and ifenprodil to the amino terminal regulatory (R) domain of the N-methyl-D-aspartate receptor was studied using purified regulatory domains of the NR1, NR2A and NR2B subunits, termed NR1-R, NR2A-R and NR2B-R. The R domains were over-expressed in Escherichia coli and purified to near homogeneity. The K(d) values for binding of [(14)C]spermine to NR1-R, NR2A-R and NR2B-R were 19, 140, and 33 microM, respectively. [(3)H]Ifenprodil bound to NR1-R (K(d), 0.18 microM) and NR2B-R (K(d), 0.21 microM), but not to NR2A-R at the concentrations tested (0.1-0.8 microM). These K(d) values were confirmed by circular dichroism measurements. The K(d) values reflected their effective concentrations at intact NR1/NR2A and NR1/NR2B receptors. The results suggest that effects of spermine and ifenprodil on NMDA receptors occur through binding to the regulatory domains of the NR1, NR2A and NR2B subunits. The binding capacity of spermine or ifenprodil to a mixture of NR1-R and NR2A-R or NR1-R and NR2B-R was additive with that of each individual R domain. Binding of spermine to NR1-R and NR2B-R was not inhibited by ifenprodil and vice versa, indicating that the binding sites for spermine and ifenprodil on NR1-R and NR2B-R are distinct.

Decrease in acrolein toxicity based on the decline of polyamine oxidases.

We have shown recently that acrolein is strongly involved in cell damage during brain infarction and chronic renal failure. To study the mechanism of acrolein detoxification, we tried to isolate Neuro2a cells with reduced sensitivity to acrolein toxicity (Neuro2a-ATD cells). In one cell line, Neuro2a-ATD1, the level of glutathione (GSH) was increased. We recently isolated a second cell line, Neuro2a-ATD2, and found that acrolein-producing enzymes [polyamine oxidases (PAO); i.e. acetylpolyamine oxidase (AcPAO), and spermine oxidase (SMO)] are reduced in this cell line due to changes at the level of transcription. In the Neuro2a-ATD2 cells, the IC50 of acrolein increased from 4.2 to 6.8µM, and the levels of FosB and C/EBPß - transcription factors involved in the transcription of AcPAO and SMO genes - were reduced. Transfection of siRNAs for FosB and C/EBPß reduced the levels of AcPAO and SMO, respectively. In addition, the synthesis of FosB and AcPAO was also decreased by siRNA for C/EBPß, because C/EBPß is one of the transcription factors for the FosB gene. It was also found that transfection of siRNA for C/EBPß decreased SMO promoter activity in Neuro2a cells but not in ATD2 cells confirming that a decrease in C/EBPß is involved in the reduced SMO activity in Neuro2a-ATD2 cells. Furthermore, transfection of the cDNA for AcPAO or SMO into Neuro2a cells increased the toxicity of acrolein. These results suggest that acrolein is mainly produced from polyamines by PAO.

Molecular mechanism underlying promiscuous polyamine recognition by spermidine acetyltransferase.

Spermidine acetyltransferase (SAT) from Escherichia coli, which catalyses the transfer of acetyl groups from acetyl-CoA to spermidine, is a key enzyme in controlling polyamine levels in prokaryotic cells. In this study, we determined the crystal structure of SAT in complex with spermidine (SPD) and CoA at 2.5Å resolution. SAT is a dodecamer organized as a hexamer of dimers. The secondary structural element and folding topology of the SAT dimer resemble those of spermidine/spermine N(1)-acetyltransferase (SSAT), suggesting an evolutionary link between SAT and SSAT. However, the polyamine specificity of SAT is distinct from that of SSAT and is promiscuous. The SPD molecule is also located at the inter-dimer interface. The distance between SPD and CoA molecules is 13Å. A deep, highly acidic, water-filled cavity encompasses the SPD and CoA binding sites. Structure-based mutagenesis and in-vitro assays identified SPD-bound residues, and the acidic residues lining the walls of the cavity are mostly essential for enzymatic activities. Based on mutagenesis and structural data, we propose an acetylation mechanism underlying promiscuous polyamine recognition for SAT.

Functional characterization of the human spermidine/spermine N(1)-acetyltransferase gene promoter.

Spermidine/spermine N(1)-acetyltransferase (SSAT), the key enzyme of polyamine catabolism, is induced by antiproliferative stresses. We analyzed the 5' flanking region of the human SSAT gene, and clarified that the binding of Sp1 to the GC-box located 42 to 51 bp upstream from the transcription start site is essential for transcription in HeLa S3 cells. A polyamine-responsive element (PRE) seemed to be responsible for the elevated transcription after X-ray irradiation.

Polyamine oxidase and acrolein as novel biochemical markers for diagnosis of cerebral stroke.

BACKGROUND AND PURPOSE: We found previously that plasma levels of acrolein (CH2=CHCHO) and spermine oxidase (SMO) were well correlated with the degree of severity of chronic renal failure. The aim of this study was to test whether the levels of these 2 markers and of acetylpolyamine oxidase (AcPAO) were increased in the plasma of stroke patients. METHODS: The activity of AcPAO and SMO and the level of protein-conjugated acrolein in plasma of the stroke patients and normal subjects were measured by high-performance liquid chromatography and ELISA, respectively. Focal infarcts were estimated by MRI or computed tomography (CT). RESULTS: The levels of AcPAO, SMO, and acrolein were significantly increased in the plasma of stroke patients. The size of stroke was nearly parallel with the multiplied value of acrolein and total polyamine oxidase (AcPAO plus SMO). After the onset of stroke, an increase in AcPAO first occurred, followed by increased levels of SMO and finally acrolein. In 1 case, an increase in AcPAO and SMO preceded focal damage as detected by MRI or CT. Furthermore, stroke was confirmed by MRI in a number of mildly symptomatic patients (11 cases) who had increased levels of total polyamine oxidase and acrolein. Among apparently normal subjects (8 cases) who had high values of acroleinxtotal polyamine oxidase, stroke was found in 4 cases by MRI. CONCLUSIONS: The results indicate that increased levels of AcPAO, SMO, and acrolein are good markers of stroke.

Differential expression of NMDA receptor subunits between neurons containing and not containing enkephalin in the mouse embryo spinal cord.

We transfected cultures of mouse spinal cord slices with the enhanced green fluorescent protein (GFP) gene driven by the promoter for preproenkephalin, using the particle-mediated gene transfer system adapted for small neurons in the superficial dorsal horn, and observations were made after 4-6 days in vitro. A considerable number of cells in the superficial dorsal horn were observed to express GFP fluorescence, reminiscent of the previously reported distribution of enkephalinergic neurons in the spinal cord. The number of GFP-expressing neurons increased in response to forskolin application. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of single neurons revealed that the N-methyl-d-aspartate (NMDA) receptor NR2B subunit is expressed more frequently in enkephalinergic neurons, and the NR2A subunit more frequently in non-enkephalinergic neurons. These observations suggest that expression of NMDA receptor subunits is controlled differentially in distinct populations of neurochemically identified neurons in the spinal cord. Biolistic particle-mediated gene transfection seems useful for identifying neuronal phenotypes in organotypic cultures of the spinal cord.

Composition of glycosaminoglycans in elasmobranchs including several deep-sea sharks: identification of chondroitin/dermatan sulfate from the dried fins of Isurus oxyrinchus and Prionace glauca.

Shark fin, used as a food, is a rich source of glycosaminoglyans (GAGs), acidic polysaccharides having important biological activities, suggesting their nutraceutical and pharmaceutical application. A comprehensive survey of GAGs derived from the fin was performed on 11 elasmobranchs, including several deep sea sharks. Chondroitin sulfate (CS) and hyaluronic acid (HA) were found in Isurus oxyrinchus, Prionace glauca, Scyliorhinus torazame, Deania calcea, Chlamydoselachus anguineus, Mitsukurina owatoni, Mustelus griseus and Dasyatis akajei, respectively. CS was only found from Chimaera phantasma, Dalatias licha, and Odontaspis ferox, respectively. Characteristic disaccharide units of most of the CS were comprised of C- and D-type units. Interestingly, substantial amount of CS/dermatan sulfate (DS) was found in the dried fin (without skin and cartilage) of Isurus oxyrinchus and Prionace glauca. 1H-NMR analysis showed that the composition of glucuronic acid (GlcA) and iduronic acid (IdoA) in shark CS/DS was 41.2% and 58.8% (Isurus oxyrinchus), 36.1% and 63.9% (Prionace glauca), respectively. Furthermore, a substantial proportion of this CS/DS consisted of E-, B- and D-type units. Shark CS/DS stimulated neurite outgrowth of hippocampal neurons at a similar level as DS derived from invertebrate species. Midkine and pleiotrophin interact strongly with CS/DS from Isurus oxyrinchus and Prionace glauca, affording Kd values of 1.07 nM, 6.25 nM and 1.70 nM, 1.88 nM, respectively. These results strongly suggest that the IdoA-rich domain of CS/DS is required for neurite outgrowth activity. A detailed examination of oligosaccharide residues, produced by chondroitinase ACII digestion, suggested that the IdoA and B-type units as well as A- and C-type units were found in clusters in shark CS/DS. In addition, it was discovered that the contents of B-type units in these IdoA-rich domain increased in a length dependent manner, while C- and D-type units were located particularly in the immediate vicinity of the IdoA-rich domain.

Correlation between methotrexate-induced intestinal damage and decrease in polyamine content.

A synthetic analog of prostaglandin E(1), OP-1206 [17S, 20-dimethyl-trans-Delta(2)-prostaglandin E(1)] protects the small intestine from the methotrexate (MTX)-induced damage. The purpose of this study is to evaluate the protective effect of OP-1206 on the methotrexate-induced small intestinal damage in rats from the biochemical point of view. MTX (15 mg/kg body weight) was orally administered to rats once daily for 5 days. OP-1206 (0.5 microg/kg body weight) was orally administered to rats twice a day for 5 days, and on the 6th day biochemical components in the jejunal mucosa of the treated rats were determined. The contents of DNA, RNA, proteins and polyamines (spermine and spermidine) in the jejunal mucosa of rats were markedly decreased by the MTX treatment. The coadministration of OP-1206 with MTX prevented such decreases caused by the MTX treatment. The MTX treatment decreased the incorporation of 3H-thymidine into DNA in the jejunal mucosa, while the coadministration of OP-1206 with MTX prevented it. These results indicated that OP-1206 could protect the intestinal mucosa against the biochemical effects of MTX through a trophic action on intestinal villi. Further, it should be noted that polyamines may possibly play an important role of modulation action on intestinal mucosa.