Causal relationship between hypertension and risk of constipation: A 2-way 2-sample Mendelian randomization study.

Patients with hypertension have a higher risk of having constipation and vice versa. The causal association between these 2 variables is not proven. We performed a retrospective Mendelian randomization analysis to determine the causal association between constipation and hypertension. Two-sample 2-way Mendelian randomization analysis was used. Genetic variants for constipation were derived from genome-wide association study data of European origin (15,902 cases and 395,721 controls). Corresponding genetic associations for hypertension were derived from European ancestry GWAS data (54,358 cases and 408,652 controls). Genetic susceptibility to hypertension was associated with an increased risk of constipation (OR: 3.459, 95% CI: 1.820-6.573, P < .001). In an inverse Mendelian randomization analysis, no causal effect of constipation on hypertension was found (OR: 0.999, 95% CI: 0.987-1.011, P = .834). In sensitivity analyses, these associations persisted and no multiple effects were found. This study suggests that there is a causal relationship between hypertension and constipation and that hypertension may increase the risk of developing constipation.

Analysis of differentially expressed lncRNAs and mRNAs associated with slow­transit constipation.

Slow transit constipation (STC) is a refractory gastrointestinal disease, accounting for approximately 13 âˆ¼ 37 % of chronic constipation. However, the molecular mechanism of STC remains poorly understood. Herein, this study aims to identify the key mRNAs and lncRNAs associated with STC. To this end, we performed high-throughput RNA sequencing to identify differentially expressed (DE) mRNAs and lncRNAs in the whole-layer sigmoid intestinal tissues from 4 STC patients and 4 non-STC patients. The identified DE lncRNAs and mRNAs were validated through quantitative real-time PCR. Weighted gene co-expression network analysis (WGCNA) and Pearson correlation analysis were conducted to determine the significantly correlated DE mRNA-lncRNA pairs. A total of 1420 DE lncRNAs and 1634 DE mRNAs were identified. Kyoto Encyclopedia of Genes and Genomes analysis of DE mRNAs indicated that these DE mRNAs might be associated with systemic lupus erythematosus, alcoholism, intestinal immune network for IgA production, inflammatory bowel disease, NF-kappa B signaling pathway. WGCNA and Pearson correlation analyses jointly identified 16,577 significantly correlated DE mRNA-lncRNA pairs. Furthermore, lncRNAs LINC00641, LINC02268, LINC03013 were identified as hub lncRNAs. The protein-protein interaction (PPI) network of proteins encoded by DE mRNAs was established, and PPI-based analysis revealed that Interleukin 2(IL2), CD80 molecule (CD80), interleukin-17A (IL-17A) might play significant roles in the development of STC. This study analyzes the expression profiles of lncRNAs and mRNAs associated with STC. Our findings will contribute to further understanding of the molecular mechanism of STC and provide potential diagnostic or therapeutic biomarkers for STC.

Integrated metabolomics and transcriptomics revealed the anti-constipation mechanisms of xylooligosaccharides from corn cobs.

Xylooligosaccharides (XOSs) have recently garnered interest for their potential as an anti-constipation agent. In this study, we investigated the effects of XOSs derived from corn cobs on constipation in mice through a comprehensive analysis of both the metabolome and transcriptome. Our multi-omics approach revealed that XOSs primarily modulated butanoate metabolism and steroid hormone biosynthesis pathways, as well as key signaling pathways such as PPAR and NF-kappa B. Notably, we observed a decrease in inflammatory biomarker expression and an elevation of butyric acid metabolite levels with XOSs treatment. A deeper analysis of gene expression and metabolite alterations highlighted significant changes in genes encoding critical enzymes and metabolites involved in these pathways. Overall, these findings underscore the considerable potential of XOSs derived from corn cobs as a dietary supplement for effectively alleviating constipation.

Regional homogeneity alterations in patients with functional constipation and their associations with gene expression profiles.

Functional constipation, a highly prevalent functional gastrointestinal disorder, often accompanies by mental and psychological disorders. Previous neuroimaging studies have demonstrated brain functional and structural alterations in patients with functional constipation. However, little is known about whether and how regional homogeneity is altered in these patients. Moreover, the potential genetic mechanisms associated with these alterations remain largely unknown. The study included 73 patients with functional constipation and 68 healthy controls, and regional homogeneity comparison was conducted to identify the abnormal spontaneous brain activities in patients with functional constipation. Using Allen Human Brain Atlas, we further investigated gene expression profiles associated with regional homogeneity alterations in functional constipation patients with partial least squares regression analysis applied. Compared with healthy controls, functional constipation patients demonstrated significantly decreased regional homogeneity in both bilateral caudate nucleus, putamen, anterior insula, thalamus and right middle cingulate cortex, supplementary motor area, and increased regional homogeneity in the bilateral orbitofrontal cortex. Genes related to synaptic signaling, central nervous system development, fatty acid metabolism, and immunity were spatially correlated with abnormal regional homogeneity patterns. Our findings showed significant regional homogeneity alterations in functional constipation patients, and the changes may be caused by complex polygenetic and poly-pathway mechanisms, which provides a new perspective on functional constipation's pathophysiology.

Hetong decoction relieves loperamide-induced constipation in rats by regulating expression of aquaporins.

OBJECTIVE: To investigate whether Hetong decoction (, HTT) alleviates constipation via regulating AQPs expression. METHODS: Constipation in rats was induced by loperamide, and rats were randomly assigned into model (saline), HHT-low (95 g/kg), HTT-medium (190 g/kg), HTT-high (380 g/kg) and positive control (mosapride) groups. Then the defecation function, the concentration of serum arginine vasopressin (AVP) and cyclic adenosine monophosphate (cAMP), and the expression of AQP3 and AQP8 in colon tissues were assessed. NCM460 colon cells with AQP3 and AQP8 knockdown or overexpression were exposed to serum from rats that received low or high dose of HTT, followed by detection of AQP3 and AQP8 expression. RESULTS: The model group showed lower fecal weight and water content, weaker intestinal transit, higher serum concentration of AVP and cAMP, increased proximal and distal AQP8 expression, increased proximal but decreased distal AQP3 expression. However, these trends were reversed in both the HTT group (low, medium and high dose) and the positive control group. In NCM460 cells, HTT dose-dependently stabilized AQP3 and AQP8 expression under AQP3/8 plasmid interference or overexpression. CONCLUSIONS: HTT relieves constipation in rats through regulating AQP3 and AQP8 expression.

[Genetic testing and prenatal diagnosis for a Chinese pedigree affected with Waardenburg syndrome type 4C due to heterozygous deletion of SOX10 gene].

OBJECTIVE: To explore the genetic basis for a Chinese pedigree featuring congenital profound syndromic deafness and chronic constipation, and provide prenatal diagnosis for a high-risk fetus. METHODS: Whole-exome sequencing was carried out to analyze the sequences of genes associated with hereditary deafness, and multiplex ligation-dependent probe amplification (MLPA) was used to verify the candidate variant in the proband's parents and the fetus. RESULTS: The proband was found to have harbored a heterozygous deletion of SOX10, a pathogenic gene associated with Waardenburg syndrome type 4C (WS4C). The same deletion was found in her mother (with profound syndromic deafness and chronic constipation) and the fetus, but not in her father with normal hearing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG) and Association for Molecular Pathology (AMP), the SOX10 gene deletion was predicted to be a pathogenic variant (PVS1+PM2_Supporting+PP1+PP4). CONCLUSION: The pedigree was diagnosed with WS4C, which has conformed to an autosomal dominant inheritance. Deletion of the entire SOX10 gene, as a loss-of-function variant, probably underlay its pathogenesis. Above finding has facilitated genetic counseling and prenatal diagnosis for this family.

Baizhu-Baishao herb pair ameliorates functional constipation and intestinal microflora disorder in rats.

BACKGROUND: In China, Rhizoma atractylodis macrocephalae-Paeonia lactiflora Pall (Biazhu-Baishao, BZBS) is a classic herb pair used to treat intestinal stress syndrome, ulcerative colitis and other diseases. However, the mechanism of BZBS in the treatment of functional constipation (FC) has been little studied and remains unclear. In this study, a behavioral investigation, colon tissue morphology, enzyme-linked immunosorbent assay (Elisa) and intestinal microflora analysis have been used to illuminate the potential mechanism of the effects of BZBS on FC in a rat model. METHODS: A FC rat model was constructed and BZBS was given as treatment. Observations and recordings were made of the fecal moisture content, the defecation time of the first black stool, and the rate of intestinal propulsion. Elisa was used to detect the expression levels of substance P (SP), vasoactive intestinal peptide (VIP), 5-hydroxytryptamine (5-HT) in the colon. To ascertain the composition of the microbial community, a high throughput 16S ribosomal RNA (16S rRNA) gene sequencing technique was employed. RESULTS: Oral administration of BZBS significantly ameliorated several key excretion parameters, including the time to first black stool defecation, stool water content, and the propulsion rate in the small intestine in FC rats. It increased the expression of SP, VIP and 5-HT in the colon. 16S rRNA gene sequencing results showed that BZBS changed the microbial community structure, decreased the Bacteroidetes/Firmicutes ratio, increased the relative abundance of Blautia and Fusicatenibacter, and decreased the relative abundance of Ruminococcus and Roseburia. CONCLUSIONS: BZBS effectively alleviates FC and improves dysbacteriosis.

[Effect of deep needling "Tianshu" (ST25) on colonic motility in rats with slow transit constipation].

OBJECTIVE: To observe the effect of acupuncture of "Tianshu"(ST25) at different depths on colonic transportation function, expressions of colonic substance P (SP) and interstitial cells of Cajal (ICC) in rats with slow transit constipation (STC), so as to explore its mechanisms underlying improvement of STC．. METHODS: Fifty male Wistar rats were selected and randomly divided into control，STC model，conventional acupuncture，deep needling group 1 and deep needling group 2 groups，with 10 rats in each group．The STC model was established by gavage of 1 mg/mL compound diphenoxylate suspension (10 mg/kg), once every other day for 21 days, and rats of the control group were given the same dose of distilled water by gavage．EA (2 Hz, 2 mA) was applied to "Tianshu"(ST25), with the acupuncture needle inserted to a depth of 3 mm for rats of the conventional acupuncture group, 4.5 mm for those of deep needling group 1, and 10 mm for those of the deep needling group 2. The acupuncture needle was twirled for 1 min, then retained for 15 min each time, once a day for 15 consecutive days．Following modeling, rats of the 4 groups and the control group received gavage of active carbon 2 mL (100 g/L) for observing the excretion time of the first black stool grain to assess the intestinal transit function. The colonic myoelectric activities (frequency and amplitude) were recorded by using BIOPAC multichannel physiograph. The immunoactivity of SP and c-kit (a transmembrane protein kinase for identification of ICC) of colonic musculature was detected by immunohistochemistry. RESULTS: Compared with the control group，the time of excretion of the first black stool grain, and the amplitude of colonic electromyogram (EMG) were significantly increased (P<0.01), while the frequency of EMG, expressions of SP and c-kit (ICC) were significantly decreased in the model group (P<0.01). In contrast to the model group, both deep needling group 1 and 2 had a decrease in the time of excretion of the first black stool grain, and amplitude of intestinal EMG, and an increase of frequency of intestinal EMG, and immunoactivity of SP and c-kit (P<0.01). The effect of deep needling 2 is superior to that of deep needling 1 in reducing the time of excretion of the first black stool grain (P<0.05), lowering the amplitude of EMG of the gut smooth muscle (P<0.05) and in increasing the frequency of EMG (P<0.05) and the expressions of SP and c-kit (P<0.05). No significant changes were found in the levels of frequency and amplitude of EMG, and expressions of SP and c-kit after routine needling in comparison with the model group (P>0.05), except the excretion time of the first black stool grain (P<0.05). CONCLUSION: Deep needling at ST25 at depth of 4.5 mm and 10 mm，especially at depth of 10 mm，has a significant effect in promoting gut motility to ameliorate constipation in rats with STC, which may be related to its function in up-regulating the expressions of SP and ICC activity.

Protective effect of L-pipecolic acid on constipation in C57BL/6 mice based on gut microbiome and serum metabolomic.

BACKGROUND: Functional constipation (FC) in children affects their growth, development and quality of life. L-pipecolic acid (L-PA) was decreased in FC children based on gut microbiome and serum metabolomic. In this study, loperamide-induced constipation in mice was used to evaluate the effects of L-PA on constipated mice. METHOD: 26 FC and 28 healthy children were recruited. Stool samples and serum samples were subjected to 16S rDNA sequencing and ultra-performance liquid chromatography/quadrupole time of flight (UPLC-Q/TOF-MS) approach, respectively. A loperamide-induced mouse constipation model was developed, and all mice were randomly divided into control (Con), loperamide (Lop) and L-PA (Lop + L-PA) treatment groups (6 mice per group). The mice in the Lop + L-PA group were given L-PA (250 mg/kg, once a day) and loperamide; the Lop group was given loperamide for 1 week, and the Con group was given saline. The fecal parameters and intestinal motility of mice in each group were detected. serum 5-HT levels and colon 5-HT expression were detected by ELISA and immunohistochemistry, respectively; qRT-PCR was used to detect the expression of AQP3 and 5-HT4R mRNA in each group. RESULTS: 45 differential metabolites and 18 significantly different microbiota were found in FC children. The α and ß diversity of gut microbiota in FC children was significantly reduced. Importantly, serum L-PA was significantly reduced in FC children. The KEGG pathway enrichment were mainly enriched in fatty acid biosynthesis, lysine degradation, and choline metabolism. L-PA was negatively associated with Ochrobactrum, and N6, N6, N6-trimethyl-l-lysine was positively associated with Phascolarcrobacterium. In addition, L-PA improved the fecal water content, intestinal transit rate, and increased the serum 5-HT levels in constipated mice. Moreover, L-PA increased the expression of 5-HT4R, reduced AQP3, and regulated constipation-associated genes. CONCLUSIONS: Gut microbiota and serum metabolites were significantly altered in children with FC. The abundance of Phascolarctobacterium and Ochrobactrum and serum L-PA content were decreased in FC children. L-PA was found to alleviate the fecal water content, increase intestinal transit rate and the first black stool defecation time. L-PA improved constipation by increasing 5-HT and 5-HT4R expression while down-regulating AQP3 expression.

Serotonin, ghrelin, and motilin gene/receptor/transporter polymorphisms in childhood functional constipation.

OBJECTIVE: Functional constipation is the most common form of constipation, and its exact aetiology is still unclear. However, it is known that deficiencies in hormonal factors cause constipation by changing physiological mechanisms. Motilin, ghrelin, serotonin acetylcholine, nitric oxide, and vasoactive intestinal polypeptide are factors that play a role in colon motility. There are a limited number of studies in the literature where hormone levels and gene polymorphisms of serotonin and motilin are examined. Our study aimed to investigate the role of motilin, ghrelin, and serotonin gene/receptor/transporter polymorphisms in constipation pathogenesis in patients diagnosed with functional constipation according to the Rome 4 criteria. METHODS: Sociodemographic data, symptom duration, accompanying findings, the presence of constipation in the family, Rome 4 criteria, and clinical findings according to Bristol scale of 200 cases (100 constipated patients and 100 healthy control) who applied to Istanbul Haseki Training and Research Hospital, Pediatric Gastroenterology Outpatient Clinic, between March and September 2019 (6-month period) were recorded. Polymorphisms of motilin-MLN (rs2281820), serotonin receptor-HTR3A (rs1062613), serotonin transporter-5-HTT (rs1042173), ghrelin-GHRL (rs27647), and ghrelin receptor-GHSR (rs572169) were detected by real-time PCR. RESULTS: There was no difference between the two groups in terms of sociodemographic characteristics. Notably, 40% of the constipated group had a family history of constipation. The number of patients who started to have constipation under 24 months was 78, and the number of patients who started to have constipation after 24 months was 22. There was no significant difference between constipation and control groups in terms of genotype and allele frequencies in MLN, HTR3A, 5-HTT, GHRL, and GHSR polymorphisms (p<0.05). Considering only the constipated group, the rates of gene polymorphism were similar among those with/without a positive family history of constipation, constipation onset age, those with/without fissures, those with/without skin tag, and those with type 1/type 2 stool types according to the Bristol stool scale. CONCLUSION: Our study results showed that gene polymorphisms of these three hormones may not be related to constipation in children.

Colonic TRPV4 overexpression is related to constipation severity.

BACKGROUND: Chronic constipation is prevalent and involves both colon sensitivity and various changes in intestinal bacteria, particularly mucosa-associated microflora. Here we examined regulatory mechanisms of TRPV4 expression by co-culturing colon epithelial cell lines with intestinal bacteria and their derivatives. We also investigated TRPV4 expression in colon epithelium from patients with constipation. METHODS: Colon epithelial cell lines were co-cultured with various enterobacteria (bacterial components and supernatant), folate, LPS, or short chain fatty acids. TRPV4 expression levels and promoter DNA methylation were assessed using pyrosequencing, and microarray network analysis. For human samples, correlation coefficients were calculated and multiple regression analyses were used to examine the association between clinical background, rectal TRPV4 expression level and mucosa-associated microbiota. RESULTS: Co-culture of CCD841 cells with P. acnes, C. perfringens, or S. aureus transiently decreased TRPV4 expression but did not induce methylation. Co-culture with clinical isolates and standard strains of K. oxytoca, E. faecalis, or E. coli increased TRPV4 expression in CCD841 cells, and TRPV4 and TNF-alpha expression were increased by E. coli culture supernatants but not bacterial components. Although folate, LPS, IL-6, TNF-alpha, or SCFAs alone did not alter TRPV4 expression, TRPV4 expression following exposure to E. coli culture supernatants was inhibited by butyrate or TNF-alphaR1 inhibitor and increased by p38 inhibitor. Microarray network analysis showed activation of TNF-alpha, cytokines, and NOD signaling. TRPV4 expression was higher in constipated patients from the terminal ileum to the colorectum, and multiple regression analyses showed that low stool frequency, frequency of defecation aids, and duration were associated with TRPV4 expression. Meanwhile, incomplete defecation, time required to defecate, and number of defecation failures per 24 h were associated with increased E. faecalis frequency. CONCLUSIONS: Colon epithelium cells had increased TRPV4 expression upon co-culture with K. oxytoca, E. faecalis, or E. coli supernatants, as well as TNFα-stimulated TNFαR1 expression via a pathway other than p38. Butyrate treatment suppressed this increase. Epithelial TRPV4 expression was increased in constipated patients, suggesting that TRPV4 together with increased frequency of E. faecalis may be involved in the pathogenesis of various constipation symptoms.

Morphological and Functional Colonic Defects Caused by a Mutated Thyroid Hormone Receptor α.

Background: Mutations of thyroid hormone receptor α (TRα1) result in resistance to thyroid hormone (RTHα), exhibiting symptoms of retarded growth, delayed bone maturation, anemia, and severe constipation. Using a mouse model of RTHα (Thra1PV/+ mouse), we aimed at understanding the molecular basis underlying the severe constipation observed in patients. Methods: The Thra1PV/+ mouse expresses a strong dominant negative mutant, PV, which has lost T3 binding and transcription activity. Thra1PV/+ mouse faithfully reproduces growth abnormalities and anemia as shown in RTHα patients and therefore is a valid model to examine causes of severe constipation in patients. We used histopathological analysis, confocal fluorescence imaging, transmission electron microscopy (TEM), and gene expression profiles to comprehensively analyze the colonic abnormalities of Thra1PV/+ mouse. Results: We found a significant increase in colonic transit time and decrease stool water content in Thra1PV/+ mouse, mimicking constipation as found in patients. Histopathological analysis showed expanded lamina propria filled with interstitium fluid between crypt columns, enlarged muscularis mucosa, and increased content of collagen in expanded submucosa. The TEM analysis revealed shorter muscle fibers with wider gap junctions between muscle cells, fewer caveolae, and hypoplastic interstitial cells of Cajal (ICC) in the rectal smooth muscles of Thra1PV/+ mice. These abnormal histological manifestations suggested defective intercellular transfer of small molecules, electrolytes, and signals for communication among muscles cells, validated by Lucifer Yellow transferring assays. Expression of key smooth muscle contractility regulators, such as calmodulin, myosin light-chain kinase, and phosphorylated myosin light chain, was markedly lower, and c-KIT signaling in ICC was attenuated, resulting in decreased contractility of the rectal smooth muscles of Thra1PV/+ mice. Collectively, these abnormal histopathological alterations and diminished contractility regulators led to the constipation exhibited in patients. Conclusions: This is the first demonstration that TRα1 mutants could act to cause abnormal rectum smooth muscle organization, defects in intercellular exchange of small molecules, and decreased expression of contractility regulators to weaken the contractility of rectal smooth muscles. These findings provide new insights into the molecular basis underlying constipation found in RTHα patients.

Effect and mechanism of functional compound fruit drink on gut microbiota in constipation mice.

Compound fruit drink (CFD) is a functional drink prepared with fruit, Chinese herbs and prebiotic fructooligosaccharide as the main ingredients. Loperamide hydrochloride was used to establish a mouse model of constipation. And the effect of CFD on the improvement of constipation and the impact on gut microbiota were studied. The results showed that CFD significantly enhanced intestinal motility in constipated mice (P < 0.05). It significantly improved serum levels of gastrointestinal regulatory-related peptides, elevated the short-chain fatty acids (SCFAs) content and alleviated colonic injury. Meanwhile, CFD also up-regulated the mRNA expression levels of AQP3, AQP9, SCF and c-Kit and the related protein expression levels. Fecal microbial results showed that the CFD medium-dose group significantly increased species richness. Furthermore, CFD increased the abundance of potentially beneficial bacteria and reduced the number of potentially pathogenic bacteria. This study indicated that CFD was a promising functional drink for effectively relieving constipation.

Genetic testing and prenatal diagnosis for a Chinese pedigree affected with Waardenburg syndrome type 4C due to heterozygous deletion of SOX10 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a Chinese pedigree featuring congenital profound syndromic deafness and chronic constipation, and provide prenatal diagnosis for a high-risk fetus.@*METHODS@#Whole-exome sequencing was carried out to analyze the sequences of genes associated with hereditary deafness, and multiplex ligation-dependent probe amplification (MLPA) was used to verify the candidate variant in the proband's parents and the fetus.@*RESULTS@#The proband was found to have harbored a heterozygous deletion of SOX10, a pathogenic gene associated with Waardenburg syndrome type 4C (WS4C). The same deletion was found in her mother (with profound syndromic deafness and chronic constipation) and the fetus, but not in her father with normal hearing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG) and Association for Molecular Pathology (AMP), the SOX10 gene deletion was predicted to be a pathogenic variant (PVS1+PM2_Supporting+PP1+PP4).@*CONCLUSION@#The pedigree was diagnosed with WS4C, which has conformed to an autosomal dominant inheritance. Deletion of the entire SOX10 gene, as a loss-of-function variant, probably underlay its pathogenesis. Above finding has facilitated genetic counseling and prenatal diagnosis for this family.

[Effects of electroacupuncture at "Zhongliao" and "Xialiao" on serotonin signaling system and short-chain fatty acids in slow transit constipation rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) at "Zhongliao" (BL33) and "Xialiao" (BL34) on the 5-hydroxytryptamine (5-HT) signaling system in colon tissue and short-chain fatty acids in feces of rats with slow transit constipation (STC), so as to explore the underlying mechanisms of EA in the treatment of STC. METHODS: A total of 32 SD rats were randomly divided into normal, model, drug control and EA groups, with 8 rats in each group. The STC model was established by intragastric administration of loperamide for 14 days. The EA stimulation (2 Hz/15 Hz) was performed at bilateral BL33 and BL34 for 30 min, once a day for 14 days. The first black stool de-fecation time and fecal water content were detected after treatment. The expressions of 5-hydroxytryptamine 4 receptor (5-HT4R), tryptophan hydroxylase 1 (TPH1) and 5-HT transporter (SERT) in colon tissues were detected by Western blot. The contents of substance P (SP) and vasoactive intestinal peptide (VIP) in serum were detected by ELISA. The contents of 5-HT in colon tissue and short chain fatty acid (SCFA) in feces were detected by mass spectrometry. RESULTS: Compared with the normal group, the fecal water content, the expressions of 5-HT, 5-HT4R, TPH1 and SERT in colon tissue, the content of serum SP were significantly decreased (P<0.05), the first black stool de-fecation time, and the content of serum VIP was significantly increased (P<0.05), the contents of SCFA in feces were significantly decreased except isobutyric acid (P<0.05) in the model group. Compared with the model group, the fecal water content, the expressions of 5-HT, 5-HT4R, TPH1 and SERT in colon tissues, the contents of acetic acid and butyrate in feces were significantly increased (P<0.05) in the EA and drug control groups, the first black stool defecation time was decreased (P<0.05) in the EA and drug control groups, and the content of serum SP was increased and the content of serum VIP was decreased (P<0.05) in the EA group. Compared with the drug control group, the content of serum VIP was significantly decreased (P<0.05), and the expressions of TPH1 and SERT in colon tissue were significantly increased (P<0.05) in the EA group. CONCLUSION: EA at BL33 and BL34 can promote intestinal motility by intervening multiple links of 5-HT signaling system in treating STC.

Similarities and differences in constipation phenotypes between Lep knockout mice and high fat diet-induced obesity mice.

CRISPR-Cas9-mediated leptin (Lep) knockout (KO) mice exhibited prominent phenotypes for constipation, even though they were not compared with other model animals. This study compared the stool excretion, gastrointestinal motility, histological structure, mucin secretion, and enteric nerve function in Lep KO and high fat diet (HFD)-treated mice to determine if there were differences in their phenotypes for constipation. Most obesity phenotypes, including fat weight, adipocyte size, expression of lipolytic proteins (HSL, perilipin, and ATGL), and glucose concentrations, were detected similarly in the Lep KO and HFD-treated mice. They showed a similar decrease in the excretion parameters, including the stool number, weight, and water content, while the same pattern was detected in the gastrointestinal motility and intestinal length. A similar decrease in the mucosal layer thickness, muscle thickness, ability for mucin secretion, and expression of water channel (aquaporin 3 and 8) genes was detected in the mid-colon of the Lep KO and HFD-treated mice, but the alteration rate in some levels was greater in the HFD-treated group than the Lep KO mice. On the other hand, the levels of c-kit, nNOS, NSE, and PGP9.5 expression for the enteric neurons and intestitial cells of Cajal (ICC) were remarkably lower in the mid-colon of the HFD-treated mice than in the Lep KO mice, but the level of most proteins in both groups remained lower than those in the control group. A similar alteration pattern in the expression of muscarinic acetylcholine receptors (mAChRs) and serotonin receptors was detected in the Lep KO and HFD-treated mice. These results suggest that most phenotypes for obesity-induced constipation were similarly detected in the Lep KO and HFD-treated mice, but there was a difference in the regulatory function of the enteric nervous system (ENS).

Effect of miR-129-3p on autophagy of interstitial cells of Cajal in slow transit constipation through SCF C-kit signaling pathway.

OBJECTIVE: To explore the mechanism by which miR-129-3p affected the autophagy of interstitial cells of Cajal (ICCs) in slow transit constipation tissues through the SCF C-kit signaling pathway. METHODS: Colon samples from 20 Slow transit constipation (STC) patients who underwent total colectomy plus ileorectal anastomosis or subtotal colon resection plus anti-peristaltic rectal anastomosis were collected in our hospital. The colon of 20 non-STC patients was used as control. The control of this study was 20 patients undergoing radical surgery for colon cancer (left colon cancer) in our hospital. Fifty healthy SPF Kunming mice were purchased from Liaoning Changsheng Biotechnology Co., Ltd. RESULTS: The mRNA expression of miR-129-3p in the STC group was lower than that in the control group (CTLR) group (P<0.05). The mRNA expression of miR-129-3p in STC group was lower than that in the NC group (P<0.05), and mRNA expression in STC+miR-129-3p group was higher than that in STC+miR-NC group (P<0.05). In the first week, the weight of dry and wet feces of the STC group was lower than that of the NC mice (P<0.05), and the weight of dry feces and wet feces of the STC group was lower than that of the NC group at the 2, 3, and 4 weeks, STC+miR-129 -3p was higher than that in the STC group (P<0.05). CONCLUSION: The increased expression of C-kit and SCF regulated by miR-129-3p contributed to the protection of interstitial cells. Knockdown of miR-129-3p expression could inhibit the activation of AKT/mTOR signaling pathway, reduce cell proliferation activity.

METTL3 contributes to slow transit constipation by regulating miR-30b-5p/PIK3R2/Akt/mTOR signaling cascade through DGCR8.

BACKGROUND: N6-methyladenosine (m6A) is the most prevalent methylation modification of eukaryotic RNA, and methyltransferase-like 3 (METTL3) plays a vital role in multiple cell functions. This study aimed to investigate the role of m6A methylase METTL3 in slow transit constipation (STC). MATERIAL AND METHOD: The expression of METTL3 and DGCR8 was measured in STC tissues and glutamic acid-induced interstitial cells of Cajal (ICCs). The effects of METTL3, miR-30b-5p, and DGCR8 on the biological characteristics of ICCs were investigated on the basis of loss-of-function analyses. Luciferase reporter assay was used to identify the direct binding sites of miR-30b-5p with PIK3R2. RESULTS: The results showed that the METTL3, DGCR8, miR-30b-5p, and the methylation level of m6A were significantly increased in STC tissues and glutamic acid-induced ICCs. Silencing of METTL3 and miR-30b-5p inhibited apoptosis, autophagy, and pyroptosis of glutamic acid-induced ICCs. Moreover, overexpression of miR-30b-5p reversed the cytoprotection of METTL3 knockdown in glutamic acid-induced ICCs. Besides, DGCR8 knockdown could facilitate cell growth and decrease apoptotic glutamic acid-induced ICCs. Mechanically, we illustrated that METTL3 in glutamic acid-induced ICCs significantly accelerated the maturation of pri-miR-30b-5p by m6A methylation modification, resulting in the reduction of PIK3R2, which results in the inhibition of PI3K/Akt/mTOR pathway and ultimately leads to the cell death of STC. CONCLUSIONS: Collectively, these data demonstrated that METTL3 promoted the apoptosis, autophagy, and pyroptosis of glutamic acid-induced ICCs by interacting with the DGCR8 and successively modulating the miR-30b-5p/PIK3R2 axis in an m6A-dependent manner, and METTL3 may be a potential therapeutic target for STC.

Dysregulation of the Enteric Nervous System in the Mid Colon of Complement Component 3 Knockout Mice with Constipation Phenotypes.

Complement component 3 (C3) contributes to neurogenesis, neural migration, and synaptic elimination under normal and disease conditions of the brain, even though it has not been studied in the enteric nervous system (ENS). To determine the role of C3 in the regulatory mechanism of ENS during C3 deficiency-induced constipation, the changes in the markers of neuronal and interstitial cells of Cajal (ICCs), the markers for excitatory and inhibitory transmission of ENS, and expression of C3 receptors were analyzed in the mid colon of C3 knockout (KO) mice at 16 weeks of age. Prominent constipation phenotypes, including the decrease in stool parameters, changes in the histological structure, and suppression of mucin secretion, were detected in C3 KO mice compared to wildtype (WT) mice. The expression levels of the neuron specific enolase (NSE), protein gene product 9.5 (PGP9.5), and C-kit markers for myenteric neurons and ICCs were lower in the mid colon of C3 KO mice than WT mice. Excitatory transmission analysis revealed similar suppression of the 5-hydroxytryptamine (5-HT) concentration, expression of 5-HT receptors, acetylcholine (ACh) concentration, ACh esterase (AChE) activity, and expression of muscarinic ACh receptors (mAChRs), despite the mAChRs downstream signaling pathway being activated in the mid colon of C3 KO mice. In inhibitory transmission analysis, C3 KO mice showed an increase in the nitric oxide (NO) concentration and inducible nitric oxide synthase (iNOS) expression, while neuronal NOS (nNOS) expression, cholecystokinin (CCK), and gastrin concentration were decreased in the same mice. Furthermore, the levels of C3a receptor (C3aR) and C3bR expression were enhanced in the mid colon of C3 KO mice compared to the WT mice during C3 deficiency-induced constipation. Overall, these results indicate that a dysregulation of the ENS may play an important role in C3 deficiency-induced constipation in the mid colon of C3 KO mice.

Characterization of Circular RNA Expression Profiles in Colon Specimens of Patients with Slow Transit Constipation.

Background: Slow transit constipation (STC) is a clinical syndrome characterized by a decreased urge to defecate and delayed colonic transit. Circular RNAs (circRNAs) are a recently discovered class of regulatory RNAs that have emerged as critical biomarkers and regulators of various diseases. However, the expression profiles and mechanisms underlying circRNA regulation in human STC tissues have not been explored. Methods: High-throughput RNA sequencing technology was used to compare the differences in circRNA expression profiles in colon samples taken from patients with STC or controls. Bioinformatics analyses were performed on the host genes of the differentially expressed circRNAs (DE-circRNAs), a competing endogenous RNA network was constructed, and the expression levels of some DE-circRNAs were verified using quantitative real-time polymerase chain reactions (qRT-PCR). Results: There were 190 DE-circRNAs identified in the STC group. Bioinformatics analysis predicted that the DE-circRNAs were enriched in the relaxation of smooth muscle, actin binding, actin cytoskeleton organization, dilated cardiomyopathy, and cardiac muscle contraction. These results suggest that muscle diseases may be related to the pathogenesis of STC. The expression levels of the 12 most differentially expressed circRNAs were verified using qRT-PCR. In addition, circRNA-microRNA-mRNA regulatory networks were constructed using the 8 most significant circRNAs. Some mRNAs predicted to be closely related to smooth muscle function were found in these networks. Conclusions: This study provides a helpful blueprint for researchers to select candidate circRNAs for further study of the pathogenesis of STC and screen potential biomarkers or targets for use in the diagnosis and treatment of STC.