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Objective: Although prostate calcification is often identified on pelvic CT images, calcification itself is usually not considered clinically significant. A recent histological study proposed an association between prostate calcification and prostate cancer occurrence. Our aim was to determine the predictive value of prostate calcifications for future prostate cancer occurrence. Methods: We retrospectively analysed male patients (≥50 years old) without prior prostate cancer history, who underwent unenhanced pelvic CT between April 2010 and March 2011, and followed-up until December 2021. Cox proportional hazards models were used to assess prostate cancer risk with prostate calcification (defined as a high-density area larger than 3 mm with CT attenuation values ≥ 130 HU), controlling for age, body mass index (BMI), hypertension and diabetes mellitus. Results: A total of 636 male patients (mean age, 68 years ± 9 [standard deviation]) were evaluated. At the end of follow-up, prostate cancer had been more frequently diagnosed in patients with prostate calcification than those without prostate calcification (6.5% vs 2.6%). Multivariate analysis revealed that prostate calcification on CT was a significant predictor of future prostate cancer occurrence (hazard ratio [HR], 2.7; 95% CI: 1.20, 5.91; p = 0.016). No statistical differences were observed in any other factors. Conclusion: Prostate calcification may be a significant predictor of future prostate cancer occurrence, and may be used for risk stratification and to guide screening protocols. Advances in knowledge: Presence of prostate calcification on unenhanced CT scan was associated with increased incidence of prostate cancer occurrence on long term follow-up.

AIM Selenoprotein P (SeP, encoded by SELENOP in humans) is a hepatokine that causes insulin resistance in the liver and skeletal muscle. It was found that polyunsaturated fatty acid eicosapentaenoic acid (EPA) downregulates Selenop expression by inactivating SREBP-1c. The present study aimed to examine the effect of EPA for 12 weeks on circulating SeP levels and insulin sensitivity in humans with type 2 diabetes. METHODS A total of 20 participants with dyslipidemia and type 2 diabetes were randomly assigned to an EPA (900 mg, twice daily) group and a control group. The primary endpoint was a change in serum SeP levels. Organ-specific insulin sensitivity in the liver (HGP and %HGP), skeletal muscle (Rd), and adipose tissue (FFA and %FFA) were assessed using a hyperinsulinemic-euglycemic clamp study with stable isotope-labeled glucose infusion. RESULTS Serum SeP levels were not changed in either group at the end of the study. In the EPA group, the changes in SeP levels were positively correlated with the change in serum EPA levels (r = 0.709, P = 0.022). Treatment with EPA significantly enhanced %FFA but not %HGP and Rd. The change in serum EPA levels was significantly positively correlated with the change in %HGP, and negatively correlated with changes in Rd. CONCLUSIONS The change in serum EPA levels was positively correlated with serum SeP levels, hepatic insulin sensitivity, and negatively with skeletal muscle insulin sensitivity in humans with type 2 diabetes. The EPA-induced enhancement of hepatic insulin sensitivity might be associated with a mechanism independent of serum SeP levels.

Selenoprotein P (SeP; encoded by SEPP1 in humans) is a hepatokine that causes impaired insulin secretion and insulin resistance. Metformin downregulates SELENOP promoter activity through an adenosine monophosphate-activated kinase-forkhead box protein O3a pathway in hepatocytes. This study aimed to test our hypothesis that circulating SeP levels are associated with the glucose-lowering effect of metformin in humans.A total of 84 participants with poorly controlled type 2 diabetes were randomly assigned to receive metformin (1,000 mg, twice daily) or a dipeptidyl peptidase-4 inhibitor, alogliptin (25 mg, once daily) for 12 weeks. We tested metformin and alogliptin on SeP levels and factors associated therewith as a post-hoc analysis.Both metformin and aloglipitin did not change the SeP levels. Although metformin significantly increased the insulin secretory index secretory units of islets in transplantation only in participants with higher baseline SeP (3.87), both agents similarly reduced fasting plasma glucose and glycated hemoglobin. SeP levels at baseline were correlated negatively with changes in SeP (r = -0.484, P = 0.004) and fasting plasma glucose (r = -0.433, P = 0.011), and positively with changes in C-peptide immunoreactivity (r = 0.420, P = 0.017) and secretory units of islets in transplantation (r = 0.388, P = 0.028) in the metformin, but not alogliptin, group.Higher baseline levels of SeP significantly predicted metformin-mediated, but not alogliptin-mediated, glucose-lowering and insulinotropic effects. Serum SeP levels might be a novel biomarker for predicting the outcomes of metformin therapy, which might be helpful in tailoring diabetes medication.

Selenoprotein P (SeP) is a selenium (Se)-rich extracellular protein. SeP is identified as a hepatokine, causing insulin resistance in type 2 diabetes. Thus, the measurement of SeP in serum has received much attention, and several enzyme-linked immunosorbent assay (ELISA) kits for SeP determination are now commercially available. In the present study, we determined the serum SeP levels by our original ELISA and sol particle homogeneous immunoassay (SPIA) methods and also by commercially available kits, and these determinants were compared. We found a kit-dependent correlation of the determinants with our methods. These results suggest that the selection of kit is critical for comparison with our previous reports and for discussing the relationship between the serum SeP levels and disease condition.

A hepatokine is a collective term for liver-derived secretory factors whose previously-unrecognized functions have been recently elucidated. We have rediscovered selenoprotein P (SeP) and leukocyte cell-derived chemotaxin 2 (LECT2) as hepatokines that are involved in the development of insulin resistance and hyperglycemia. The aim of this study was to determine whether and, if so, how oral glucose loading alters the two hepatokines in humans. We measured concentrations of serum SeP and plasma LECT2 during 75 g oral glucose tolerance test (OGTT) (n = 20) in people with various degrees of glucose tolerance. In OGTT, concentrations of both serum SeP and plasma LECT2 decreased at 120 min compared with the baseline values, irrespective of the severity of glucose intolerance. Decrement of serum SeP during OGTT showed no correlations to the clinical parameters associated with insulin resistance or insulin secretion. In multiple stepwise regression analyses, plasma cortisol was selected as the variable to explain the changes in plasma concentrations of LECT2. The current data reveal the acute inhibitory actions of oral intake of glucose on circulating SeP and LECT2 in humans, irrespective of the severity of glucose intolerance. This study suggests that circulating SeP is regulated by the unknown clinical factors other than insulin and glucose during OGTT.

Hepatokines are liver-secreted proteins with potential to influence glucose regulation and other metabolic parameters. This study investigated differences in adiposity status on 5 novel hepatokines and characterised their response to acute moderate-intensity exercise in groups of normal-weight and overweight/obese men. Twenty-two men were recruited into normal-weight and overweight/obese groups (body mass index: 18.5 to 24.9 and 25.0 to 34.9 kg·m−2). Each completed 2 experimental trials, exercise and control. During exercise trials, participants performed 60 min of moderate-intensity treadmill exercise (∼60% peak oxygen uptake) and then rested for 6 h. Participants rested throughout control trials. Circulating fibroblast growth factor-21 (FGF21), follistatin, leukocyte cell-derived chemotaxin 2 (LECT2), fetuin-A, and selenoprotein-P (SeP) were measured throughout. Fasted (resting) FGF21 and LECT2 were higher in overweight/obese individuals (129% and 55%; P ≤ 0.01) and correlated with indices of adiposity and insulin resistance; whereas circulating follistatin was lower in overweight/obese individuals throughout trial days (17%, P < 0.05). In both groups, circulating concentrations of FGF21 and follistatin were transiently elevated after exercise for up to 6 h (P ≤ 0.02). Circulating fetuin-A and SeP were no different between groups (P ≥ 0.19) and, along with LECT2, were unaffected by exercise (P ≥ 0.06). These findings show that increased adiposity is associated with a modified hepatokine profile, which may represent a novel mechanism linking excess adiposity to metabolic health. Furthermore, acute perturbations in circulating FGF21 and follistatin after exercise may contribute to the health benefits of an active lifestyle.

Exercise has numerous health-promoting effects in humans; however, individual responsiveness to exercise with regard to endurance or metabolic health differs markedly. This 'exercise resistance' is considered to be congenital, with no evident acquired causative factors. Here we show that the anti-oxidative hepatokine selenoprotein P (SeP) causes exercise resistance through its muscle receptor low-density lipoprotein receptor-related protein 1 (LRP1). SeP-deficient mice showed a 'super-endurance' phenotype after exercise training, as well as enhanced reactive oxygen species (ROS) production, AMP-activated protein kinase (AMPK) phosphorylation and peroxisome proliferative activated receptor γ coactivator (Ppargc)-1α (also known as PGC-1α; encoded by Ppargc1a) expression in skeletal muscle. Supplementation with the anti-oxidant N-acetylcysteine (NAC) reduced ROS production and the endurance capacity in SeP-deficient mice. SeP treatment impaired hydrogen-peroxide-induced adaptations through LRP1 in cultured myotubes and suppressed exercise-induced AMPK phosphorylation and Ppargc1a gene expression in mouse skeletal muscle-effects which were blunted in mice with a muscle-specific LRP1 deficiency. Furthermore, we found that increased amounts of circulating SeP predicted the ineffectiveness of training on endurance capacity in humans. Our study suggests that inhibitors of the SeP-LRP1 axis may function as exercise-enhancing drugs to treat diseases associated with a sedentary lifestyle.

Several novel A-ring modified analogs of 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] have been synthesized in order to investigate the structure-function relationships of 1alpha,25(OH)2D3. We synthesized A-ring modified analogs which contain a methyl group on C-2 of the A-ring. There are eight 2-methyl diastereomers, which differ in the stereochemistry of the methyl group on C-2 and the hydroxyl groups on C-1 and C-3. Further our biological activity studies of the 2-methyl diastereomers indicated that the potency of each analog is highly dependent on the stereochemistry of the A-ring substituents [Konno et al., Biorg. Med. Chem. Letts. 8(2), 151-156 (1998); Nakagawa et al., Biochem. Pharmacol. 60(12), 1937-1947 (2000)]. For example, the VDR binding affinities exhibited by the 1alpha-isomers are significantly higher than those exhibited by the 1beta-isomers. Furthermore, out of all the 1alpha-isomers, the 2alpha-methyl isomers, when compared to the corresponding 2beta-methyl isomers, showed much higher potency in inducing cell differentiation of HL-60 cells, but failed to stimulate apoptosis. In contrast the 2beta-methyl isomers strongly stimulated apoptosis. At present it is unknown how the addition of the 2-methyl modification to the hormone, 1alpha,25(OH)2D3 alters its metabolism in target tissues. Previously, we reported that 1alpha,25(OH)2D3 is metabolized in rat osteosarcoma (UMR 106) cells via both the C-24 oxidation and the C-3 epimerization pathways. Therefore, we studied the metabolism of the four 1alpha,2-methyl diastereomers in UMR 106 cells. Our results indicated that in UMR 106 cells, all four diastereomers were metabolized into several polar metabolites via the C-24 oxidation pathway. Thus, the presence of the 2-methyl group on the A-ring did not inhibit the metabolism of the analogs via the C-24 oxidation pathway. However, it is significant to note that the 2-methyl group prevented the metabolism of the analogs via the C-3 epimerization pathway. In summary, we report that the 2-methyl group interferes with the action of the enzyme(s) involved in C-3 epimerization, but not with the enzyme 1alpha,25(OH)2D3-24-hydroxylase, which is responsible for C-24 oxidation pathway.

The syntheses and biological evaluations of (23R)- and (23S)-24,24-difluoro-1 alpha,23,25-trithydroxyvitamin D3 (3a and 3b), new C-24 fluorinated analogs of 1 alpha,25-dihydroxyvitamin D3, are described. The syntheses of these compounds were achieved in 3 steps from (5Z,7E,20R)-1 alpha,3 beta-bis-[(tert-butyldimethylsilyl)oxy]-20-formylmethyl-9,10-seco- 5,7,10(19) pregnatriene (5) which is derived from vitamin D2. The absolute configuration at the C-23 position of 3a and 3b was determined by the modified Mosher method. The relative affinities of 3a and 3b to the vitamin D receptor were both 10 and 14 times lower than that of 1 alpha,25-dihydroxyvitamin D3 (1), and to vitamin D binding protein were also both 130 and 40 times lower. The HL-60 cell differentiating activity of 3a was 6 times more potent than that of 1, while there was no remarkable difference in activity between 3b and 1.

The first synthesis of the title compound 4, a novel analog of 1α-hydroxyvitamin D (α-calcidiol) that might be therapeutically useful, is described. A key feature in the synthesis is the radical deoxygenation of the diol 21, which was prepared according to the previously reported procedure starting from 17. The resulting deoxygenated product 22 with the desired side-chain moiety was finally led to 4 in a conventional manner. Some aspects of the unusual reactivity of 25-OH on radical deoxygenation are also discussed.

Recent advances in the methodology for the synthesis of vitamin D analogs are reviewed. The synthetic methods of vitamin D are classified into three types of the approaches ; (1) conversions from steroid compounds (2) convergent synthesis (3) partial conversions from readily available vitamin D2 or D3. Their merits and demerits are discussed by using some examples from recent literatures (mainly after 1985). Modifications of vitamin D by fluorine atom (s) are also discussed briefly.

4, 6-Dihydrothieno[3, 4-c]furan-5, 5-dioxide (1), a novel precursor of a bis-diene, reacts with quinones to afford the normal Diels-Alder adducts, the quinone-annelated 2, 3-bis (methlene)-7-oxabicyclo[2.2.1]-heptane derivatives. Promising building blocks(3b and 5) for the synthesis of the antineoplastic antibiotics are prepared by this method.

4-Acyl-4H,6H-thieno[3,4-c]furan 5,5-dioxides have been prepared and submitted to Diels–Alder reactions to afford dienes with greater steric congestion after desulfonylation.

This review deals with our recent works on the preparation of heteroaromatic-fused 3-sulfolenes (5) and their chemistry, especially Diels-Alder reactions with several dienophiles under thermal or high pressure conditions. Related chemistry of the positional isomers (6) is also reviewed

4H,6H-thieno[3,4-c]furan 5,5-dioxide 1 was readily converted to the 4-alkylated compounds 2 and the appropriate compounds 2 were submitted to intramolecular Diels–Alder reactions to afford fused furans 8a and b in good yields.

Reaction of the title compound 2 with a variety of alkylating agents regioselectively gave, depending on the reaction conditions used, 4-alkylated compound 3 or 6-alkylated compound 4, which were further alkylated to afford the dialkylated compounds 5–7 in similar ways.

New building blocks, 3,5-dihydro-1 H -thieno[3,4- c ]pyrrole 2,2-dioxides 3 , have been prepared by the oxidation of their corresponding pyrroline derivatives 4 with DDQ or Chemical MnO 2 . The Diels-Alder reaction of 3 with dimethyl acetylenedicarboxylate gave new types of compunds: 7-aza-2,3-dimethylenenorbornenes A , the 1:2 adducts B , 1a,3a,6,9-tetrahydrobenz[ g ]indoles C , and dihydroindolosulfolene D depending on the reaction conditions and the N -substituents. The reaction of 3 with bis( tert -butylsulfonyl)acetylene was also described.

Electrochemical oxidation of naturally occurring allylic alcohols is described. Under direct anodic oxidation conditions, prenol 1 was readily oxidized, followed by rearrangement presumably on the surface of the anodic electrode, to give 3-hydroxy-2,2′-dimethyl-1,1′-dimethoxy propane 2 in high yield, whereas geraniol 5 afforded citral 6 under the same conditions.

An improved synthesis of a highly potent vitamin D3 analog, 24, 24-difluoro-1α, 25-dihydroxyvitamin D3 (1b)has been accomplished via vitamin D2-SO2 adducts. The introduction of fluorine atoms was performed by treating the α-keto ester (11) with diethylaminosulfur trifluoride. The total yield was 12.5% from inexpensive vitamin D2 in 11 steps. This sequence is sufficiently straightforward to be conducted on a gram scale.

In spite of the absence of activating groups for dienophiles, N-substituted 3,5-dihydro-1H-thieno[3,4-c]pyrrole S,S-dioxides 1 which contain terminal olefin substituents, undergo facile intramolecular Diels–Alder reaction and subsequent spontaneous desulfonylation to give the corresponding tricyclic azanorbornane framework 2 in good yields.

The intramolecular Diels–Alder reaction of the 2-acyl derivative of 4H,6H-thieno[3,4-c]furan 5,5-dioxide 2a is achieved by the use of molecular sieves as additive to give the corresponding cycloadduct 4a in high yield. Addition of efeoophiles to this reaction media afforded the polycyclic compounds 5 and 7a–cvia tandem cycloaddition in a single step.

Selective oxidation of terminal isopropyl groups to the correspoding tertiary alcohols by an electrochemical method is described. Under the conditions using the Tl(TFA) 3 -hematoporphyrin-O 2 -cathodic reduction system, several substrates such as cholesterol ( 1 ) and Grundmann's alcohol ( 3 ) gave the corresponding tertiary alcohols 2 and 4 , respectively, in reasonable yield.

Synthesis and biological evaluation of all eight possible A-ring diastereomers of 2-methyl-20-epi-1,25-dihydroxyvitamin D3 are described. Among the analogues synthesized, 2α-methyl-20-epi-1α,25-dihydroxyvitamin D3 exhibited exceptionally high potency. The double modification of 2-methyl substitution and 20-epimerization yielded analogues with unique activity profiles.

Novel oxidation of vitamin D 2 was achieved by an electrochemical method. Under the conditions employing a metal salt-hematoporphyrin-O 2 -cathodic reduction system, only the conjugated triene moiety of vitamin D 2 was affected, giving the cleavage products, while the double bond in the side chain remained intact.

Novel 2alpha-substituted 1alpha,25-dihydroxyvitamin D3 analogues were efficiently synthesized and their biological activities were evaluated. 2alpha-Methyl-1alpha,25-dihydroxyvitamin D3 (2), whose unique biological activities were previously reported, was modified to 2alpha-alkyl (ethyl and propyl) and 2alpha-hydroxyalkyl (hydroxymethyl, hydroxyethyl, and hydroxypropyl) analogues 3-7 by elongation of the alkyl chain and/or introduction of a terminal hydroxyl group. 2alpha-Hydroxypropyl-1alpha,25-dihydroxyvitamin D3 (7) exhibited an exceptionally potent calcium-regulating effect and a unique activity profile.

It was established that exclusively high regioselective C O bond cleavage of 7-oxabicyclo[2.2.1]heptane skeletons, which are unique Diels–Alder products of furans, under mild conditions using samarium(II) iodide and samarium powder yields cyclohexanol derivatives or aromatic compounds.

Our studies on creation of functional organic compounds and their applications, have focused on three areas, namely, (A) organic chemical studies on VD (vitamin D) analogues, (B) studies on solitary wasp venoms, and (C) studies on functional building blocks for organic synthesis. In the first area, several novel and important vitamin D analogues were synthesized and biologically evaluated, and their high VDR (vitamin D receptor) binding affinities were discussed on the basis of conformational analysis and docking study by Molecular Mechanics Calculation to the LBD (ligand binding domain) of VDR: These compounds include 24,24-difluoro-1 alpha,25-dihydroxy-VD3 (2) (an antimetabolism agent, the first VD analogue having higher potency than the natural hormone (1)), 2 alpha-methyl-1 alpha,25-dihydroxy-VD3 (42b) (the first A-ring-modified VD analogue exhibiting stronger VDR affinity than 1) and its 20-epimer (43b) (a VD analogue having a highest HL-60 cell differentiation inducing activity with a relatively low calcemic effect), and 2 alpha-(omega-hydroxypropyl)-1 alpha,25-dihydroxy-VD3 (exceptionally high calcemic effect). In the second area, we isolated and determined the structure of pompilidotoxins (76, 77), novel peptide neurotoxins in solitary wasp venoms. In the third area, we created furan-fused 3-sulfolene, 4H, 6H-thieno [3,4-c]-furan 5,5-dioxide and pyrrole-fused 3-sulfolene (96), 3,5-dihydro-1H-thieno[3,4-c] pyrrole 2,2-dioxide (125), and studied their inter- and intramolecular Diels-Alder reactions.

Novel 2α-substituted 1α,25-dihydroxyvitamin D3 analogues with 2α-alkyl and 2α-hydroxyalkyl groups were systematically synthesized from d-xylose. Their conformation on binding to the ligand binding domain (LBD) of the vitamin D receptor was analyzed. It has been found that the 2α-hydroxypropyl group best fits the cavity of the LBD, and the binding activity is three times higher than that for the natural hormone.

An alternative synthesis of the title compound 2, a highly potent analog of 1α, 25-dihydroxyvitamin D3 (1), is described. Starting with 1α, 3β-bis[(tert-butyldimethylsilyl)oxy]androst-5-ene (8), 2 was obtained in 3.8% total yield through 10 steps. This method provides compound 2 in much higher yield than that reported previously.

Biological activities of 2alpha-substituted 1alpha,25-dihydroxyvitamin D3 analogues were evaluated in vitro. Their binding affinity was examined with calf thymus cytosolic vitamin D receptor (VDR) and rat plasma vitamin D-binding protein (DBP). In addition, the transcriptional activity of the analogues was measured using a rat 25-hydroxyvitamin D3-24-hydroxylase gene promoter, a human osteocalcin gene promoter, and VDR-GAL4 system. This study investigated the biological activities of 2alpha-substituted analogues in comparison with 2beta-substitued analogues at the molecular level, with regard to the structural differences of alkyl, hydroxyalkyl, hydroxyalkoxy substituents at the 2-position of 1alpha,25-dihydroxyvitamin D3.

A concise route to the Trost A-ring precursor enyne for synthesizing 2a-substituted 1α,25-dihydroxyvitamin D3 (1) is described, in which the 2a-substituents could be introduced via addition reaction of Grignard reagent towards the sugar epoxide, easily obtained from D-glucose. In the reaction, the solvent effect was remarkable and the use of toluene gave higher chemical yield and chemical reactivity as compared with ethereal solvents.

Novel efficient synthesis of several enantio-pure 2-alkylated 1α,25-dihydroxy-19-norvitamin D 3 analogues through radical introduction of 2-alkyl chain and C 5 -C 6 position coupling using Julia-type olefination as key steps was established starting from commercially available (-)-quinic acid as a chiral pool.

Syntheses of PNA monomers whose nucleobases are protected with Boc group are described. To overcome the solubility problem of carboxymethyl-guanine derivative, we introduced 2-trimethylsilylethyI group at O6 as a second protecting group.

The design and synthesis of new 1α,25-dihydroxy-19-norvitamin D3 analogues 3a–c, which have an amide bond in the molecule instead of the diene, are described. The A-ring moiety was constructed by a (3S,5S)-3,5-dihydroxypiperidine derivative (9, 11, or 13) prepared from d -mannose, and a CD-ring carboxylic acid 16 was synthesized from Grundmann's ketone. Coupling those parts gave desired 3a–c in good yield. This strategy can be applied in combinatorial chemistry; therefore, those compounds would be applicable as useful tools in the development of new drugs.

The 2alpha-methyl-, 2alpha-(3-hydroxypropyl)-, and 2alpha-(3-hydroxypropoxy)-derivatives of the 'double side chain' analogue of 1alpha,25-dihydroxyvitamin D(3) were synthesized using Trost A-ring/CD-ring connective strategy. Regarding the requisite A-ring building blocks, a new, high yield and stereoselective route to the 2alpha-methyl compound starting from D-glucose was developed. All three new analogues showed potent HL-60 cancer cell differentiation activity.