Aging of enteric neuromuscular systems in gastrointestinal tract

BACKGROUND

Aging is a complex biological process and associated with a progressive decline in functions of most organs including the gastrointestinal (GI) tract. Age-related GI motor disorders/dysfunctions include esophageal reflux, dysphagia, constipation, fecal incontinence, reduced compliance, and accommodation. Although the incidence and severity of these diseases and conditions increase with age, they are often underestimated due in part to nonspecific and variable symptoms and lack of sufficient medical attention. They negatively affect quality of life and predispose the elderly to other diseases, sarcopenia, and frailty. The mechanisms underlying aging-associated GI dysfunctions remain unclear, and there is limited data examining the effect of aging on GI motor functions. Many studies on aging-associated changes to cells within the tunica muscularis including enteric neurons, smooth muscles, and interstitial cells have proposed that cell loss and/or molecular changes may be involved in the pathogenesis of age-related GI motor disorders/dysfunctions. There is also evidence that the aging contributes to phenotypic changes in innate immune cells, which are physically and functionally linked to other cells in the tunica muscularis and can alter GI (patho) physiology. However, various patterns of changes have been reported, some of which are contradictory, indicating a need for additional work in this area.

PURPOSE

Although GI infection due to intestinal bacterial overgrowth, bleeding, and cancers are also important and common problems in the elderly patients, this mini-review focuses on data obtained from enteric neuromuscular aging research with the goal of better understanding the cellular and molecular mechanisms of enteric neuromuscular aging to enhance future therapy.

Asymmetric Michael reaction of malononitrile and α,β-unsaturated aldehydes catalyzed by diarylprolinol silyl ether

The asymmetric Michael reaction of malononitrile and α,β-unsaturated aldehydes catalyzed by diarylprolinol silyl ether was developed. Michael products were obtained in good yield and with excellent enantioselectivity without formation of overreaction products. As a malononitrile moiety can be transformed into alkoxy or amino carbonyl moieties by oxidative transformation, an α-chiral ester or amide with an all-carbon quaternary center can be synthesized with excellent enantioselectivity.

Experimental evidence of tetrahedral symmetry breaking in SiO2 glass under pressure

Bimodal behavior in the translational order of silicon's second shell in SiO₂ liquid at high temperatures and high pressures has been recognized in theoretical studies, and the fraction of the S state with high tetrahedrality is considered as structural origin of the anomalous properties. However, it has not been well identified in experiment. Here we show experimental evidence of a bimodal behavior in the translational order of silicon's second shell in SiO₂ glass under pressure. SiO₂ glass shows tetrahedral symmetry structure with separation between the first and second shells of silicon at low pressures, which corresponds to the S state structure reported in SiO₂ liquid. On the other hand, at high pressures, the silicon's second shell collapses onto the first shell, and more silicon atoms locate in the first shell. These observations indicate breaking of local tetrahedral symmetry in SiO₂ glass under pressure, as well as SiO₂ liquid.

Turbulence Spreading into an Edge Stochastic Magnetic Layer Induced by Magnetic Fluctuation and Its Impact on Divertor Heat Load

Turbulence spreading into the edge stochastic magnetic layer induced by magnetic fluctuation is observed at the sharp boundary region in the large helical device. The density fluctuation excited at the sharp boundary region with a large pressure gradient does not propagate into the boundary region due to the blocking of turbulence spreading by the large second derivative of the pressure gradient. Once the magnetic fluctuation appears at the boundary, the density fluctuation begins to penetrate the edge stochastic layer and the second derivative of the pressure gradient also decreases. The increase of density fluctuation in this layer results in the broadening and reduction of the peak divertor heat load. It is demonstrated that magnetic fluctuation plays a key role in controlling the turbulence spreading at the boundary of plasma which contributes to the reduction of divertor heat load.

Perioperative Circulating Tumor DNA Enables Identification of Patients with Poor Prognosis in Upper Tract Urothelial Carcinoma

Perioperative systemic chemotherapy improves the prognosis of upper tract urothelial carcinoma (UTUC). The first objective of this study is to verify whether perioperative circulating tumor DNA (ctDNA) analysis using a pan-cancer gene panel and next-generation sequencing can identify patients with poor prognosis who require perioperative chemotherapy. Secondly, we will investigate whether ctDNA is useful for minimal residual disease (MRD) detection and treatment monitoring in UTUC. This study included fifty patients with untreated UTUC, including 43 cases of localized UTUC. We performed targeted ultradeep sequencing of plasma cfDNA and buffy coat DNA and whole-exome sequencing of cancer tissues, allowing exclusion of possible false positives. We attempted to stratify the prognosis according to the perioperative ctDNA levels in patients with localized UTUC. In patients with metastatic UTUC, ctDNA was evaluated before, during, and after systemic treatment. Twenty-three (46%) of 50 patients with untreated UTUC were ctDNA-positive, and 17 (40%) of 43 patients with localized UTUC were ctDNA-positive. Of the detected TP53 mutations, 19% were false-positive due to clonal hematopoiesis of indeterminate potential (CHIP). Among preoperative risk factors, only the preoperative ctDNA fraction>2% was a significant and independent risk factor associated with worse recurrence-free survival (RFS). Furthermore, the existence of ctDNA early point after the operation was significantly associated with worse RFS, suggesting the presence of MRD. ctDNA also showed potential as a real-time marker for systemic therapy in patients with metastatic UTUC. Detection of ctDNA may indicate potential metastasis and guide decisions of perioperative chemotherapy.

Self-Sustained Divertor Oscillation Driven by Magnetic Island Dynamics in Torus Plasma

A new type of self-sustained divertor oscillation is discovered in the Large Helical Device stellarator, where the peripheral plasma is detached from material diverters by means of externally applied perturbation fields. The divertor oscillation is found to be a self-regulation of an isolated magnetic field structure (the magnetic island) width induced by a drastic change in a poloidal inhomogeneity of the plasma radiation across the detachment-attachment transitions. A predator-prey model between the magnetic island width and a self-generated local plasma current (the bootstrap current) is introduced to describe the divertor oscillation, which successfully reproduces the experimental observations.

Early dynamics of circulating tumor DNA predict clinical response to immune checkpoint inhibitors in metastatic renal cell carcinoma

Objectives

Detection of genomic alterations in circulating tumor deoxyribonucleic acid of peripheral blood can guide the selection of systemic therapy in cancer patients. The predictive significance of circulating tumor deoxyribonucleic acid in metastatic renal cell carcinoma remains unclear, especially for patients treated with immune checkpoint inhibitors.

Methods

In this study, we collected plasma samples before and 1 month after commencing nivolumab monotherapy or nivolumab plus ipilimumab therapy from 14 metastatic renal cell carcinoma patients. We performed circulating tumor deoxyribonucleic acid genomic profiling in plasma cell‐free deoxyribonucleic acid by next‐generation sequencing using a commercially available pan‐cancer panel (Guardant360 CDx). Additionally, we also performed whole exome sequencing of tumor tissues and compared the concordance of genomic profiles with circulating tumor deoxyribonucleic acid.

Results

Nine patients had circulating tumor deoxyribonucleic acid in pretreatment plasma samples with a total of 20 mutations (15 single nucleotide variants, three insertions/deletions, and two copy number amplification). VHL (30.0%) was the most frequently mutated gene, followed by TP53 (20.0%), and 45.0% of circulating tumor deoxyribonucleic acid mutations were concordant with somatic mutations in tumor tissues. Patients with decreasing circulating tumor deoxyribonucleic acid mutant allele frequency had better progression free survival when compared to those with increasing mutant allele frequency (P = 0.0441).

Conclusions

Our findings revealed that early circulating tumor deoxyribonucleic acid dynamics can serve as a predictive biomarker for response to immune checkpoint inhibitors in metastatic renal cell carcinoma patients.

Enantiodivergent One-Pot Synthesis of Axially Chiral Biaryls Using Organocatalyst-Mediated Enantioselective Domino Reaction and Central-to-Axial Chirality Conversion

Enantiodivergent one-pot synthesis of biaryls was developed using a catalytic amount of a single chiral source. A domino organocatalyst-mediated enantioselective Michael reaction and aldol condensation provided centrally chiral dihydronaphthalenes with excellent enantioselectivity, from which an enantiodivergent chirality conversion from central-to-axial chirality was achieved. Both enantiomers of biaryls were obtained with excellent enantioselectivity. All transformations can be conducted in a single reaction vessel. A plausible reaction mechanism for the enantiodivergence is proposed.

A narrative review of imatinib-resistant gastrointestinal stromal tumors

Objective:

Review the studies that investigate the mechanisms underlying imatinib-resistant gastrointestinal stromal tumors (GIST).

Background:

GIST are the most common mesenchymal tumors of the gastrointestinal (GI) tract and the most common sarcoma in humans. GIST are thought to be arise from interstitial cells of Cajal (ICC), pacemaker and neuromodulator cells in the GI tract, as well as “fibroblast”-like cells, which are another type of interstitial cells of the gut wall and also known as telocyte or platelet-derived growth factor-alpha (PDGFRA)-positive cells. The majority of GIST harbor gain-of-function mutations in either KIT or PDGFRA, and these gain-of-function mutations are mutually exclusive and most often heterozygous. GIST are responsive to the KIT/PDGFRA tyrosine kinase inhibitor (TKI), imatinib, the standard first-line drug for advanced and metastatic GIST. However, imatinib alone does not eradicate GIST despite an initial clinical benefit, and more than 90% of GIST harbor imatinib-resistance. Although second and third-generation TKIs have been developed and are currently in clinical use, they are not curative for refractory and metastatic GIST due to the emergence of clones with drug-resistant mutations. Eradication of drug-resistant GIST will cure patients with refractory GIST. Several mechanisms may contribute to refractory GIST. These mechanisms are secondary mutations in KIT and/or PDGFRA, alternative activation of tyrosine kinases, stem cells for GIST and cellular quiescence, a reversible nonproliferating state in which cells retain the ability to reenter cell proliferation.

Methods:

We review our current optimal treatment approach for managing patients with advanced and refractory GIST.

Conclusions:

This review explores the novel and potential therapeutic approaches to combat drug-resistant GIST.

Asymmetric Synthesis of Functionalized 9-Methyldecalins Using a Diphenylprolinol-Silyl-Ether-Mediated Domino Michael/Aldol Reaction

Substituted 9-methyldecalin derivatives containing an all carbon quaternary chiral center were synthesized with excellent enantioselectivity via an organocatalyst-mediated domino reaction. The first reaction is a diphenylprolinol silyl ether-mediated Michael reaction, and the second reaction is an intramolecular aldol reaction. The enantiomerically pure catalyst is involved in both reactions.

Three-Pot Synthesis of Chiral Anti-1,3-diols through Asymmetric Organocatalytic Aldol and Wittig Reactions Followed by Epoxidation and Reductive Opening of the Epoxide

A three-pot asymmetric synthesis of the anti-1,3-diol unit was developed. In the first pot, enantioselective aldol reaction of aldehydes proceeds, catalyzed by organocatalyst, followed by either Wittig or Horner-Wadsworth-Emmons reactions to afford δ-hydroxy α,β-unsaturated carbonyls with excellent enantioselectivity. Diastereoselective hydroxy-directed anti-epoxidation proceeds in the next pot by the use of tert-BuOOH and LiHMDS. Reductive opening of the epoxide proceeds in a third pot to afford anti-β,δ-hydroxy carbonyl compounds with excellent diastereo- and enantioselectivity.

The gut microbiota associated with high-Gleason prostate cancer

We have found that intestinal bacteria and their metabolites, short-chain fatty acids (SCFAs), promote cancer growth in prostate cancer (PCa) mouse models. To clarify the association between gut microbiota and PCa in humans, we analyzed the gut microbiota profiles of men with suspected PCa. One hundred and fifty-two Japanese men undergoing prostate biopsies (96 with cancer and 56 without cancer) were included in the study and randomly divided into two cohorts: a discovery cohort (114 samples) and a test cohort (38 samples). The gut microbiota was compared between two groups, a high-risk group (men with Grade group 2 or higher PCa) and a negative + low-risk group (men with negative biopsy or Grade group 1 PCa), using 16S rRNA gene sequencing. The relative abundances of Rikenellaceae, Alistipes, and Lachnospira, all SCFA-producing bacteria, were significantly increased in high-risk group. In receiver operating characteristic curve analysis, the index calculated from the abundance of 18 bacterial genera which were selected by least absolute shrinkage and selection operator regression detected high-risk PCa in the discovery cohort with higher accuracy than the prostate specific antigen test (area under the curve [AUC] = 0.85 vs 0.74). Validation of the index in the test cohort showed similar results (AUC = 0.81 vs 0.67). The specific bacterial taxa were associated with high-risk PCa. The gut microbiota profile could be a novel useful marker for the detection of high-risk PCa and could contribute to the carcinogenesis of PCa.

High level of phosphatidylcholines/lysophosphatidylcholine ratio in urine is associated with prostate cancer

The altered levels of phospholipids (PLs) and lysophospholipids (LPLs) in prostate cancer (CaP) and benign tissues in our previous findings prompted us to explore PLs and LPLs as potential biomarkers for CaP. Urinary lipidomics has attracted increasing attention in clinical diagnostics and prognostics for CaP. In this study, 31 prostate tissues obtained from radical prostatectomy were assessed using high‐resolution matrix‐assisted laser desorption/ionization imaging mass spectrometry (HR‐MALDI‐IMS). Urine samples were collected after digital rectal examination (DRE), and urinary lipids were extracted using the acidified Bligh‐Dyer method. The discovery set comprised 75 patients with CaP and 44 with benign prostatic hyperplasia (BPH) at Kyoto University Hospital; the validation set comprised 74 patients with CaP and 59 with BPH at Osaka University Hospital. Urinary lipidomic screening was performed using MALDI time‐of‐flight MS (MALDI‐TOF/MS). The levels of urinary lysophosphatidylcholine (LPC) and phosphatidylcholines (PCs) were compared between the CaP and BPH groups. The (PC [34:2] + PC [34:1])/LPC (16:0) ratio was significantly higher (P < .001) in CaP tissues than in benign epithelial tissues. The urinary PCs/LPC ratio was significantly higher (P < .001) in the CaP group than in the BPH group in the discovery and validation sets.

Clinical Application of TERT Promoter Mutations in Urothelial Carcinoma

Urothelial carcinoma (UC) is a common urological malignancy with a high rate of disease recurrence. Telomerase activity, a hallmark of cancer characterized by overcoming the replicative senescence, is upregulated in over 90% of patients with UC. Somatic mutations in the promoter region of telomerase reverse transcriptase (TERT) are frequently detected in UC, and drive telomerase activity. Recent studies have demonstrated a strong association between TERT promoter mutation and tumorigenesis of UC. Also, TERT promoter mutation has great potential for diagnosis, as well as prognosis in UC treatment, and this is also applicable for the liquid biopsy techniques. In this review, we discuss the progress in these areas and highlight the challenges, clinical potential, and future direction for developing UC treatment methods.

AB0442 CLINICAL FEATURES OF POLYMYOSITIS AND DERMATOMYOSITIS PATIENTS WITH SEVERE DYSPHAGIA

Background:

Polymyositis (PM) and dermatomyositis (DM) are autoimmune inflammatory diseases characterized by proximal myositis. Dysphagia has been reported to develop in 35 to 62% of PM/DM patients and known as poor prognosis factor.

Objectives:

The purpose of this study is to determine the clinical characteristics of PM/DM patients who present with deglutition disorder.

Methods:

Consecutive patients with PM/DM who visited National Hospital Organization Tokyo Medical Center between April 2010 and January 2021 are included in this study. We compared clinical features between the patients with and without dysphagia. The diagnosis of dysphagia was based on videofluorography swallow study, and dysphagia requiring gastrostomy was defined as severe dysphagia. The clinical characteristics compared in this study were following: age of onset, levels of serum creatine kinase (CK) and lactate dehydrogenase(LDH), sense of dysphagia, manual muscle test (MMT) score, and complication of malignancy or interstitial pneumonia.

Results:

A total of 73 patients with PM/DM were identified. Among them, 12 patients were diagnosed with dysphagia, and 5 patients developed severe dysphagia. Patients with dysphagia had the following characteristics compared to patients without dysphagia: higher levels of serum LDH (833.7 ± 500.1 U/L vs 471.9 ± 321.0 U/L, p = 0.0088), higher levels of serum CK at initial examination (6070.3 ± 7184.8 IU/L vs 1534.7 ± 2978.8 IU/L, p = 0.0086) and more frequent sense of dysphagia (90.9% vs 10.6%, p< 0.0001), lower MMT score(3.18 ± 1.07 vs 4.31 ± 0.75, p = 0.0017). In addition to those, patients with severe dysphagia presented older age of onset (mean age 69.4 ± 12.0 vs 51.7 ± 14.8, p = 0.014), more frequent complication of malignancy (80.0% vs 14.8%, p= 0.0048) and less frequent complication of interstitial pneumonia (0.0% vs 55.5%, p= 0.023).

Conclusion:

These results indicate that dysphagia develops frequently in PM/DM patients with higher levels of serum LDH or CK, sense of dysphagia and low MMT score. Among them, patients with elderly onset or malignancy are at risk for sever dysphagia, and should be treated carefully.

Disclosure of Interests:

None declared.

Gut Microbiota-Derived Short-Chain Fatty Acids Promote Prostate Cancer Growth via IGF1 Signaling

Excessive intake of animal fat and resultant obesity are major risk factors for prostate cancer. Because the composition of the gut microbiota is known to change with dietary composition and body type, we used prostate-specific Pten knockout mice as a prostate cancer model to investigate whether there is a gut microbiota-mediated connection between animal fat intake and prostate cancer. Oral administration of an antibiotic mixture (Abx) in prostate cancer-bearing mice fed a high-fat diet containing a large proportion of lard drastically altered the composition of the gut microbiota including Rikenellaceae and Clostridiales, inhibited prostate cancer cell proliferation, and reduced prostate Igf1 expression and circulating insulin-like growth factor-1 (IGF1) levels. In prostate cancer tissue, MAPK and PI3K activities, both downstream of the IGF1 receptor, were suppressed by Abx administration. IGF1 directly promoted the proliferation of prostate cancer cell lines DU145 and 22Rv1 in vitro. Abx administration also reduced fecal levels of short-chain fatty acids (SCFA) produced by intestinal bacteria. Supplementation with SCFAs promoted tumor growth by increasing IGF1 levels. In humans, IGF1 was found to be highly expressed in prostate cancer tissue from obese patients. In conclusion, IGF1 production stimulated by SCFAs from gut microbes influences the growth of prostate cancer via activating local prostate MAPK and PI3K signaling, indicating the existence of a gut microbiota-IGF1-prostate axis. Disrupting this axis by modulating the gut microbiota may aid in prostate cancer prevention and treatment. SIGNIFICANCE: These results suggest that intestinal bacteria, acting through short-chain fatty acids, regulate systemic and local prostate IGF1 in the host, which can promote proliferation of prostate cancer cells.

Proteomic analysis of urinary and tissue-exudative extracellular vesicles to discover novel bladder cancer biomarkers

Proteomic analysis of urinary extracellular vesicles (EVs) is a powerful approach to discover potential bladder cancer (BCa) biomarkers, however urine contains numerous EVs derived from the kidney and normal urothelial epithelium, which can obfuscate information related to BCa cell-derived EVs. In this study, we combined proteomic analysis of urinary EVs and tissue-exudative EVs (Te-EVs), which were isolated from culture medium of freshly resected viable BCa tissues. Urinary EVs were isolated from urine samples of 11 individuals (7 BCa patients and 4 healthy individuals), and Te-EVs were isolated from 7 BCa tissues. We performed tandem mass tag (TMT)-labeling liquid chromatography (LC-MS/MS) analysis for both urinary EVs and Te-EVs and identified 1960 proteins in urinary EVs and 1538 proteins in Te-EVs. Most of the proteins identified in Te-EVs were also present in urinary EVs (82.4%), with 55 of these proteins showing upregulated levels in the urine of BCa patients (fold change > 2.0; P < .1). Among them, we selected 22 membrane proteins as BCa biomarker candidates for validation using selected reaction monitoring/multiple reaction monitoring (SRM/MRM) analysis on urine samples from 70 individuals (40 BCa patients and 30 healthy individuals). Six urinary EV proteins (heat-shock protein 90, syndecan-1, myristoylated alanine-rich C-kinase substrate (MARCKS), MARCKS-related protein, tight junction protein ZO-2, and complement decay-accelerating factor) were quantified using SRM/MRM analysis and validated as significantly upregulated in BCa patients (P < .05). In conclusion, the novel strategy that combined proteomic analysis of urinary EVs and Te-EVs enabled selective detection of urinary BCa biomarkers.

Oxidative peptide bond formation of glycine-amino acid using 2-(aminomethyl)malononitrile as a glycine unit

Amide linkage of glycine-amino acid was synthesized by coupling of substituted 2-(aminomethyl)malononitrile as a C-terminal glycine unit and N-terminal amine using CsOAc and O2 in an aqueous solution. This is a coupling reagent-free and catalyst-free peptide synthesis via oxidative amide bond formation. Various tripeptides and tetrapeptides were synthesized efficiently and the sulfide moiety is inert even under an oxygen atmosphere.