TRPA1 channel mediates methylglyoxal-induced mouse bladder dysfunction

Introduction: The transient receptor potential ankyrin 1 channel (TRPA1) is expressed in urothelial cells and bladder nerve endings. Hyperglycemia in diabetic individuals induces accumulation of the highly reactive dicarbonyl compound methylglyoxal (MGO), which modulates TRPA1 activity. Long-term oral intake of MGO causes mouse bladder dysfunction. We hypothesized that TRPA1 takes part in the machinery that leads to MGO-induced bladder dysfunction. Therefore, we evaluated TRPA1 expression in the bladder and the effects of 1 h-intravesical infusion of the selective TRPA1 blocker HC-030031 (1 nmol/min) on MGO-induced cystometric alterations. Methods: Five-week-old female C57BL/6 mice received 0.5% MGO in their drinking water for 12 weeks, whereas control mice received tap water alone. Results: Compared to the control group, the protein levels and immunostaining for the MGO-derived hydroimidazolone isomer MG-H1 was increased in bladders of the MGO group, as observed in urothelium and detrusor smooth muscle. TRPA1 protein expression was significantly higher in bladder tissues of MGO compared to control group with TRPA1 immunostaining both lamina propria and urothelium, but not the detrusor smooth muscle. Void spot assays in conscious mice revealed an overactive bladder phenotype in MGO-treated mice characterized by increased number of voids and reduced volume per void. Filling cystometry in anaesthetized animals revealed an increased voiding frequency, reduced bladder capacity, and reduced voided volume in MGO compared to vehicle group, which were all reversed by HC-030031 infusion. Conclusion: TRPA1 activation is implicated in MGO-induced mouse overactive bladder. TRPA1 blockers may be useful to treat diabetic bladder dysfunction in individuals with high MGO levels.

Zinc finger protein 189 promotes the differentiation of lamina propria T helper 17.1 cells in dextran sulfate sodium-induced colitis

The factors regulating the heterogeneity of interleukin-17A (IL-17A)-expressing CD4⁺ T cells in inflammatory bowel diseases remain unclear. In the current study, we characterised the expression and function of zinc finger protein 189 (ZFP189) in a murine colitis model. Mice were given dextran sulphate sodium to induce acute colitis. Flow cytometry was applied to recognise and enrich Th17 and Th17.1 cells based on the expression of IL-17A, interferon-γ (IFN-γ), C-X-C motif chemokine receptor 3 (CXCR3), and C-C motif chemokine receptor 4 (CCR4). The expression of ZFP189 in Th17 and Th17.1 cells was determined by Immunoblotting. Lentivirus-mediated ZFP189 knockdown was conducted to evaluate the effect of ZFP189 on the differentiation of Th17 and Th17.1 cells. The adoptive transfer was performed to analyse the pathogenicity of Th17.1 cells in vivo. We found that ZFP189 was mildly up-regulated in IL-17A-expressing CD4⁺ T cells in colonic lamina propria. Lamina propria Th17.1 cells expressed higher ZFP189 than Th17 cells. In vitro ZFP189 knockdown in CD4⁺ T cells did not impact Th17 cell differentiation but suppressed Th17.1 cell differentiation, as evidenced by lower T-box expressed in T cells (T-bet) and IFN-γ. When adoptively transferred into mice, ZFP189-deficient Th17.1 cells produced fewer IFN-γ, tumour necrosis factor-alpha (TNF-α), and granulocyte-macrophage colony-stimulating factor (GM-CSF) than ZFP189-expressing Th17.1 cells. Moreover, ZFP189-deficient Th17.1 cells induced less severe colitis than ZFP189-expressing Th17.1 cells, as evidenced by less body weight loss, a lower disease activity index, and a lower colon histological score. In summary, ZFP189 acts as a positive regulator of the differentiation and pathogenicity of lamina propria Th17.1 cells in colitis.

Depth-Resolved Attenuation Mapping of the Vaginal Wall under Prolapse and after Laser Treatment Using Cross-Polarization Optical Coherence Tomography: A Pilot Study

Vaginal wall prolapse is the most common type of pelvic organ prolapse and is mainly associated with collagen bundle changes in the lamina propria. Neodymium (Nd:YAG) laser treatment was used as an innovative, minimally invasive and non-ablative procedure for the treatment of early-stage vaginal wall prolapse. The purpose of this pilot study was to assess connective tissue changes in the vaginal wall under prolapse without treatment and after Nd:YAG laser treatment using cross-polarization optical coherence tomography (CP OCT) with depth-resolved attenuation mapping. A total of 26 freshly excised samples of vaginal wall from 26 patients with age norm (n = 8), stage I-II prolapses without treatment (n = 8) and stage I-II prolapse 1-2 months after Nd:YAG laser treatment (n = 10) were assessed. As a result, for the first time, depth-resolved attenuation maps of the vaginal wall in the B-scan projection in the co- and cross-polarization channels were constructed. Two parameters within the lamina propria were target calculated: the median value and the percentages of high (≥4 mm-1) and low (<4 mm-1) attenuation coefficient values. A significant (p < 0.0001) decrease in the parameters in the case of vaginal wall prolapse compared to the age norm was identified. After laser treatment, a significant (p < 0.0001) increase in the parameters compared to the normal level was also observed. Notably, in the cross-channel, both parameters showed a greater difference between the groups than in the co-channel. Therefore, using the cross-channel achieved more reliable differentiation between the groups. To conclude, attenuation coefficient maps allow visualization and quantification of changes in the condition of the connective tissue of the vaginal wall. In the future, CP OCT could be used for in vivo detection of early-stage vaginal wall prolapse and for monitoring the effectiveness of treatment.

LDH-A Promotes Metabolic Rewiring in Leucocytes from the Intestine of Rats Treated with TNBS

Although the aetiology of inflammatory bowel diseases (IBDs) is still unknown, one of their main characteristics is that the immune system chronically affects the permeability of the intestinal lamina propria, in turn altering the composition of the microbiota. In this study, the TNBS rat model of colitis was used because it contains a complex inflammatory milieu of polymorphonuclear cells (PMN) and lymphocytes infiltrating the lamina propria. The aim of the present study was to investigate six dehydrogenases and their respective adaptations in the tissue microenvironment by quantifying enzymatic activities measured under substrate saturation conditions in epithelial cells and leukocytes from the lamina propria of rats exposed to TNBS. Our results show that in the TNBS group, an increased DAI score was observed due to the presence of haemorrhagic and necrotic areas in the colon. In addition, the activities of G6PDH and GADH enzymes were significantly decreased in the epithelium in contrast to the increased activity of these enzymes and increased lactate mediated by the LDH-A enzyme in leukocytes in the lamina propria of the colon. Over the past years, evidence has emerged illustrating how metabolism supports aspect of cellular function and how a metabolic reprogramming can drive cell differentiation and fate. Our findings show a metabolic reprogramming in colonic lamina propria leukocytes that could be supported by increased superoxide anion.

The Pannexin 1 Channel and the P2X7 Receptor Are in Complex Interplay to Regulate the Release of Soluble Ectonucleotidases in the Murine Bladder Lamina Propria

The bladder urothelium releases ATP into the lamina propria (LP) during filling, which can activate P2X receptors on afferent neurons and trigger the micturition reflex. Effective ATP concentrations are largely dependent on metabolism by membrane-bound and soluble ectonucleotidases (s-ENTDs), and the latter are released in the LP in a mechanosensitive manner. Pannexin 1 (PANX1) channel and P2X7 receptor (P2X7R) participate in urothelial ATP release and are physically and functionally coupled, hence we investigated whether they modulate s-ENTDs release. Using ultrasensitive HPLC-FLD, we evaluated the degradation of 1,N6-etheno-ATP (eATP, substrate) to eADP, eAMP, and e-adenosine (e-ADO) in extraluminal solutions that were in contact with the LP of mouse detrusor-free bladders during filling prior to substrate addition, as an indirect measure of s-ENDTS release. Deletion of Panx1 increased the distention-induced, but not the spontaneous, release of s-ENTDs, whereas activation of P2X7R by BzATP or high concentration of ATP in WT bladders increased both. In Panx1-/- bladders or WT bladders treated with the PANX1 inhibitory peptide 10Panx, however, BzATP had no effect on s-ENTDS release, suggesting that P2X7R activity depends on PANX1 channel opening. We concluded, therefore, that P2X7R and PANX1 are in complex interaction to regulate s-ENTDs release and maintain suitable ATP concentrations in the LP. Thus, while stretch-activated PANX1 hinders s-ENTDS release possibly to preserve effective ATP concentration at the end of bladder filling, P2X7R activation, presumably in cystitis, would facilitate s-ENTDs-mediated ATP degradation to counteract excessive bladder excitability.

Crosstalk between the gut microbiota and innate lymphoid cells in intestinal mucosal immunity

The human gastrointestinal mucosa is colonized by thousands of microorganisms, which participate in a variety of physiological functions. Intestinal dysbiosis is closely associated with the pathogenesis of several human diseases. Innate lymphoid cells (ILCs), which include NK cells, ILC1s, ILC2s, ILC3s and LTi cells, are a type of innate immune cells. They are enriched in the mucosal tissues of the body, and have recently received extensive attention. The gut microbiota and its metabolites play important roles in various intestinal mucosal diseases, such as inflammatory bowel disease (IBD), allergic disease, and cancer. Therefore, studies on ILCs and their interaction with the gut microbiota have great clinical significance owing to their potential for identifying pharmacotherapy targets for multiple related diseases. This review expounds on the progress in research on ILCs differentiation and development, the biological functions of the intestinal microbiota, and its interaction with ILCs in disease conditions in order to provide novel ideas for disease treatment in the future.

Development of the Neonatal Intestinal Barrier, Microbiome, and Susceptibility to NEC

The function of the intestinal barrier is partially dependent on host maturity and the colonization patterns of the microbiome to which it is exposed. Premature birth and stressors of neonatal intensive care unit (NICU)-related support (e.g., antibiotics, steroids, etc.) can alter the host internal environment resulting in changes in the intestinal barrier. Pathogenic microbial proliferation and breach of the immature intestinal barrier are proposed to be crucial steps in the development of neonatal diseases such as necrotizing enterocolitis. This article will review the current literature on the intestinal barrier in the neonatal gut, the consequences of microbiome development for this defense system, and how prematurity can influence neonatal susceptibility to gastrointestinal infection.

Development of Type 1 Diabetes in Mice Is Associated with a Decrease in IL-2-Producing ILC3 and FoxP3+ Treg in the Small Intestine

Recent data indicate the link between the number and function of T regulatory cells (Treg) in the gut immune tissue and initiation and development of autoimmunity associated with type 1 diabetes (T1D). Since type 3 innate lymphoid cells (ILC3) in the small intestine are essential for maintaining FoxP3⁺ Treg and there are no data about the possible role of ILC3 in T1D pathogenesis, the aim of this study was to explore ILC3-Treg link during the development of T1D. Mature diabetic NOD mice had lower frequencies of IL-2-producing ILC3 and Treg in small intestine lamina propria (SILP) compared to prediabetic NOD mice. Similarly, in multiple low doses of streptozotocin (MLDS)-induced T1D in C57BL/6 mice, hyperglycemic mice exhibited lower numbers of ILC3, IL-2⁺ ILC3 and Treg in SILP compared to healthy controls. To boost T1D severity, mice were treated with broad-spectrum antibiotics (ABX) for 14 days prior to T1D induction by MLDS. The higher incidence of T1D in ABX-treated mice was associated with significantly lower frequencies of IL-2⁺ ILC3 and FoxP3⁺ Treg in SILP compared with mice without ABX treatment. The obtained findings show that the lower proportions of IL-2-expressing ILC3 and FoxP3⁺ Treg in SILP coincided with diabetes progression and severity.

Challenges in Inter-rater Agreement on Lamina Propria Fibrosis in Esophageal Biopsies

BACKGROUND

Mucosal biopsies in eosinophilic esophagitis (EoE) can exhibit lamina propria (LP) fibrosis, which may portend stenotic complications; however, the histologic diagnosis of LP fibrosis is subjective. We sought to assess and improve the consistency of LP fibrosis diagnosis among our pathologist group.

METHODS

At a large pediatric hospital, 25 esophageal biopsy slides from 19 patients (16 with EoE) exhibiting a wide spectrum of LP area, artifacts, and fibrosis severity were scanned into whole-slide images. Staff pediatric pathologists (n = 8) separate from the authors classified each biopsy by LP adequacy and fibrosis severity 1 month before and after completion of an educational tutorial. Consensus was defined as >70% agreement.

RESULTS

At baseline, 16/25 (64%) cases reached consensus for no fibrosis (n = 3), fibrosis (n = 7), or inadequate LP (n = 6); agreement was fair (α = 0.34). Post-tutorial, 13/25 (52%) cases reached consensus for no fibrosis (n = 2), fibrosis (n = 7), or inadequate LP (n = 4); agreement was again fair (α = 0.33). There was moderate agreement in grading of fibrosis severity (α = 0.54).

CONCLUSION

We document only fair-to-moderate agreement in the diagnosis of esophageal LP fibrosis and adequacy in a large pediatric pathologist group despite targeted education, highlighting a challenge in incorporating this feature into EoE research and clinical decision-making.

Outcomes of nicotinic modulation on markers of intestinal IgA antibody response

Acetylcholine (ACh), as a ligand of nicotinic acetylcholine receptors (nAChRs), plays a key role in the cholinergic anti-inflammatory pathway; however, its role in the immunoglobulin A (IgA) response remains unknown. Therefore, the present study aimed to investigate the role of ACh in the intestinal biomarkers involved in IgA synthesis and the polymeric immunoglobulin receptor (pIgR) involved in IgA transcytosis. Groups of mice were administered GTS-21 (an α7nAChR agonist) or mecamylamine (a non-selective nAChR antagonist) intraperitoneally for 7 days. Intestinal fluids were used for antibody concentration assessment by ELISA, cell suspensions from Peyer's patches and the lamina propria were obtained for flow cytometric analysis of plasma cells, and CD4⁺ T-cells expressing intracellular transforming growth factor (TGF)-β and IgA-producing interleukin (IL)-4, -5, -6 and -10, and isolated epithelial cells to determine the levels of pIgR mRNA using reverse transcription-quantitative PCR. Regarding to the untreated control group, the concentration of IgA was reduced in the mecamylamine group and unaltered in the GTS-21 group while IgM levels exhibited no differences; the percentage of IgA⁺ plasma cells from Peyer's patches and the lamina propria, and the percentage of TGF-β⁺/CD4⁺ T-cells from Peyer's patches were greater in the GTS-21-group. In both treatment groups, the percentages of IgM⁺ plasma cells and IL-6⁺/IL-10⁺ CD4⁺ T cells were greater in both compartments; pIgR mRNA expression levels decreased in epithelial cells. The percentage of IL-4 CD4⁺ T-cells were greater in Peyer's patches and lower in the lamina propria in the mecamylamine group, and the percentage of IL-5 CD4⁺ T-cells in the lamina propria were decreased in both treatment groups. These findings require further examination to address the impact of cholinergic modulation on IgA-transcytosis via pIgR. The present study may be an experimental reference for clinical trials that address the role of nicotinic system in intestinal dysfunctions as postoperative ileus.

Urothelium removal does not impact mucosal activity in response to muscarinic or adrenergic receptor stimulation

The inner lining of the urinary bladder (urothelium and lamina propria, or bladder mucosa) has an important role as a tissue barrier between stored urine and the underlying smooth muscle, as well as in the modulation and regulation of bladder contractility. However, the individual influence of the apical urothelial layer on the contractile activity of this tissue is uncertain. The aim of this experiment was to identify the contractile activity of the lamina propria after removal of the urothelium. Several methods were used to mechanically disrupt the urothelium, including dabbing the tissue with a paper towel, longitudinal swipes with a cotton bud, or a longitudinal scrape with the edge of a scalpel. Hematoxylin-eosin staining was utilized to determine the level of removal of the apical urothelial cells. Spontaneous contractile activity was measured in organ baths, and responses to the agonists carbachol and isoprenaline were obtained. Three longitudinal swipes with a cotton bud was found to be the optimal method to remove the majority of the urothelium without damaging the lamina propria. Upon removal of the urothelium, the spontaneous activity of the tissue was unaltered. Similarly, responses to carbachol (1 µM) and isoprenaline (1 µM) were not affected after removal of the urothelium. The urothelium can be effectively removed without damaging the lamina propria. This apical tissue layer is not responsible for mediating the increases to spontaneous phasic activity or tonic contractions of the bladder mucosa (urothelium with lamina propria) when muscarinic or adrenergic receptors are stimulated. This research presents the lamina propria as the important cell layer mediating the overall contractile activity of the bladder wall.

E74 Like ETS Transcription Factor 3 is a Negative Regulator of Pathogenic Lamina Propria T Helper 17.1 Cells in Murine Colitis

Interleukin-17A (IL-17A)-expressing T cells, including T helper 17 (Th17) and T helper 17.1 (Th17.1) cells, play a significant role in inflammatory bowel diseases (IBDs). Identifying the mechanisms underlying the heterogeneity and plasticity of IL-17A-expressing T cells is crucial for understanding and controlling their pathogenicity. The role of E74 like ETS transcription factor 3 (ELF3) in regulating the pathogenicity of IL-17A-expressing T cells has not been studied before. Dextran sulfate sodium was used to induce acute colitis in transgenic mice co-expressing IL-17A and enhanced green fluorescent protein (EGFP). IL-17A-expressing T cells were analyzed by flow cytometry. ELF3 expression was evaluated by reverse transcription and quantitative polymerase chain reaction. Lentivirus-mediated ELF3 overexpression was performed to assess the effect of ELF3 on Th17 and Th17.1 cells in vitro. The in vivo effect of ELF3 on Th17.1 cells was analyzed in an adoptive transfer colitis model. ELF3 was expressed by IL-17A-expressing T cells in the colonic lamina propria after colitis induction. Th17 cells and Th17.1 cells were distinguished based on the expression of C-X-C motif chemokine receptor 3, cytokine production, and key regulators. Th17 cells expressed higher ELF3 than Th17.1 cells. Ectopic ELF3 overexpression did not alter Th17 cell function while suppressing Th17.1 cell function in vitro. When adoptively transferred into Rag1 knockout mice to induce colitis, ELF3-overexpressing Th17.1 cells were less pathogenic than the control Th17.1 cells. ELF3 suppresses the pathogenicity of Th17.1 cells in colitis.

Lamina propria interleukin 17 A aggravates natural killer T-cell activation in autoimmune hepatitis

Autoimmune hepatitis is an interface hepatitis characterized by the progressive destruction of the liver parenchyma, the cause of which is still obscure. Interleukin (IL)-17A is a major driver of autoimmunity, which can be produced by innate immune cells against several intracellular pathogens. Here, we investigated the involvement of IL-17A in a mice model of immune-mediated hepatitis with the intestine exposed to Salmonella typhimurium. Our results showed more severe Concanavalin (Con) A-induced liver injury and gut microbiome dysbiosis when the mice were treated with a gavage of S. typhimurium. Then, the natural killer (NK) T cells were overactivated by the accumulated IL-17A in the liver in the Con A and S. typhimurium administration group. IL-17A could activate NKT cells by inducing CD178 expression via IL-4/STAT6 signaling. Furthermore, via the portal tract, the laminae propria mucosal-associated invariant T (MAIT)-cell-derived IL-17A could be the original driver of NKT cell overactivation in intragastric administration of S. typhimurium and Con A injection. In IL-17A-deficient mice, Con A-induced liver injury and NKT cell activation were alleviated. However, when AAV-sh-mIL-17a was used to specifically knock down IL-17A in liver, it seemed that hepatic IL-17a knock down did not significantly influence the liver injury. Our results suggested that, under Con A-induction, laminae propria MAIT-derived IL-17A activated hepatic NKT, and this axis could be a therapeutic target in autoimmune liver disease.

Imatinib Mesylate Reduces Neurotrophic Factors and pERK and pAKT Expression in Urinary Bladder of Female Mice With Cyclophosphamide-Induced Cystitis

Imatinib mesylate is a tyrosine kinase inhibitor that inhibits platelet-derived growth factor receptor (PDGFR)-α, -β, stem cell factor receptor (c-KIT), and BCR-ABL. PDGFRα is expressed in a subset of interstitial cells in the lamina propria (LP) and detrusor muscle of the urinary bladder. PDGFRα + interstitial cells may contribute to bladder dysfunction conditions such as interstitial cystitis/bladder pain syndrome (IC/BPS) or overactive bladder (OAB). We have previously demonstrated that imatinib prevention via oral gavage or treatment via intravesical infusion improves urinary bladder function in mice with acute (4 hour, h) cyclophosphamide (CYP)-induced cystitis. Here, we investigate potential underlying mechanisms mediating the bladder functional improvement by imatinib using a prevention or treatment experimental design. Using qRT-PCR and ELISAs, we examined inflammatory mediators (NGF, VEGF, BDNF, CCL2, IL-6) previously shown to affect bladder function in CYP-induced cystitis. We also examined the distribution of phosphorylated (p) ERK and pAKT expression in the LP with immunohistochemistry. Imatinib prevention significantly (0.0001 ≤ p ≤ 0.05) reduced expression for all mediators examined except NGF, whereas imatinib treatment was without effect. Imatinib prevention and treatment significantly (0.0001 ≤ p ≤ 0.05) reduced pERK and pAKT expression in the upper LP (U. LP) and deeper LP (D. LP) in female mice with 4 h CYP-induced cystitis. Although we have previously demonstrated that imatinib prevention or treatment improves bladder function in mice with cystitis, the current studies suggest that reductions in inflammatory mediators contribute to prevention benefits of imatinib but not the treatment benefits of imatinib. Differential effects of imatinib prevention or treatment on inflammatory mediators may be influenced by the route and frequency of imatinib administration and may also suggest other mechanisms (e.g., changes in transepithelial resistance of the urothelium) through which imatinib may affect urinary bladder function following CYP-induced cystitis.

Bioreactors for Vocal Fold Tissue Engineering

It is estimated that almost one-third of the United States population will be affected by a vocal fold (VF) disorder during their lifespan. Promising therapies to treat VF injury and scarring are mostly centered on VF tissue engineering strategies such as the injection of engineered biomaterials and cell therapy. VF tissue engineering, however, is a challenging field as the biomechanical properties, structure, and composition of the VF tissue change upon exposure to mechanical stimulation. As a result, the development of long-term VF treatment strategies relies on the characterization of engineered tissues under a controlled mechanical environment. In this review, we highlight the importance of bioreactors as a powerful tool for VF tissue engineering with a focus on the current state of the art of bioreactors designed to mimic phonation in vitro. We discuss the influence of the phonatory environment on the development, function, injury, and healing of the VF tissue and its importance for the development of efficient therapeutic strategies. A concise and comprehensive overview of bioreactor designs, principles, operating parameters, and scalability are presented. An in-depth analysis of VF bioreactor data to date reveals that mechanical stimulation significantly influences cell viability and the expression of proinflammatory and profibrotic genes in vitro. Although the precision and accuracy of bioreactors contribute to generating reliable results, diverse gene expression profiles across the literature suggest that future efforts should focus on the standardization of bioreactor parameters to enable direct comparisons between studies. Impact statement We present a comprehensive review of bioreactors for vocal fold (VF) tissue engineering with a focus on the influence of the phonatory environment on the development, function, injury, and healing of the VFs and the importance of mimicking phonation on engineered VF tissues in vitro. Furthermore, we put forward a strong argument for the continued development of bioreactors in this area with an emphasis on the standardization of bioreactor designs, principles, operating parameters, and oscillatory regimes to enable comparisons between studies.

Functional Expression of Transient Receptor Potential and Piezo1 Channels in Cultured Interstitial Cells of Human-Bladder Lamina Propria

The interstitial cells in bladder lamina propria (LP-ICs) are believed to be involved in sensing/afferent signaling in bladder mucosa. Transient receptor potential (TRP) cation channels act as mechano- or chemo-sensors and may underlie some of the sensing function of bladder LP-ICs. We aimed to investigate the molecular and functional expression of TRP channels implicated in bladder sensory function and Piezo1/Piezo2 channels in cultured LP-ICs of the human bladder. Bladder tissues were obtained from patients undergoing cystectomy. LP-ICs were isolated and cultured, and used for real-time reverse transcription-quantitative polymerase chain reaction, immunocytochemistry, and calcium-imaging experiments. At the mRNA level, TRPA1, TRPV2, and Piezo1 were expressed most abundantly. Immunocytochemical staining showed protein expression of TRPA1, TRPV1, TRPV2, TRPV4, TRPM8, as well as Piezo1 and Piezo2. Calcium imaging using channel agonists/antagonists provided evidence for functional expression of TRPA1, TRPV2, TRPV4, Piezo1, but not of TRPV1 or TRPM8. Activation of these channels with their agonist resulted in release of adenosine triphosphate (ATP) from LP-ICs. Inhibition of TRPV2, TRPV4 and Piezo1 blocked the stretch induced intracellular Ca²⁺ increase. Whereas inhibition of TRPA1 blocked H₂O₂ evoked response in LP-ICs. Our results suggest LP-ICs of the bladder can perceive stretch or chemical stimuli via activation of TRPV2, TRPV4, Piezo1 and TRPA1 channels. LP-ICs may work together with urothelial cells for perception and transduction of mechanical or chemical signals in human-bladder mucosa.

Duodenal mast cells and eosinophils in children with celiac disease: occurrence and distribution pattern

OBJECTIVE

The aim of this study was to characterize duodenal mast cell (MC) and eosinophil (EO) numbers, their distribution within the lamina propria and possible impact on disease severity of paediatric celiac patients compared to children without celiac disease (CD).

METHODS

We analysed duodenal samples of 215 children (109 CD, 106 controls) who underwent esophagogastroduodenoscopy from 2010 to 2018. After immunohistochemical staining, average MC and EO counts were histologically examined in ten high-power-fields. Additionally, cell-distribution within the lamina propria was analysed. Possible influence of relevant clinical parameters was evaluated.

STATISTICS

Student's-t-test, Mann-Whitney U-test, Chi-square-test, ANOVA, significance-level <.05. Trial registration-number: DRKS00024669.

RESULTS

MC-density was higher in CD-patients compared to the control-group (23.7 (±12.1)/HPF versus 19.7 (±9.1)/HPF; p = .008), varying in number interindividually. Eosinophils were also increased in the duodenum of celiac patients (23.3 (±9.3)/HPF versus 12.2 (±6.3)/HPF; p= <.001). MCs were distributed more often homogenously in all parts of CD lamina propria (44 biopsies (40.4%), residing more distant from the intestinal lumen in controls (0 biopsies with homogenous distribution-pattern (0%); p= <.001). Regarding EOs no polarity was observable. Atopic diseases did not occur significantly more often in patients with elevated EO-counts.

CONCLUSION

MC- and EO-numbers were increased in the duodenum of CD-patients and MCs showed a different distribution-pattern in the lamina propria of celiac patients. These findings support the concept that both cell-types contribute to disease-pathogenesis. However, functional studies highlighting both cell-types' and their mediators' role regarding mucosal alterations during the course of the inflammatory process in celiac patients are needed.

TRIAL REGISTRATION NUMBER AND URL

DRKS00024669; https://www.drks.de/drks_web/.

Morphine mediated neutrophil infiltration in intestinal tissue play essential role in histological damage and microbial dysbiosis

The gut microbial ecosystem exhibits a complex bidirectional communication with the host and is one of the key contributing factors in determining mucosal immune homeostasis or an inflammatory state. Opioid use has been established to induce gut microbial dysbiosis consistent with increased intestinal tissue inflammation. In this study, we investigated the role of infiltrated immune cells in morphine-induced intestinal tissue damage and gut microbial dysbiosis in mice. Results reveal a significant increase in chemokine expression in intestinal tissues followed by increased neutrophil infiltration post morphine treatment which is direct consequence of a dysbiotic microbiome since the effect is attenuated in antibiotics treated animals and in germ-free mice. Neutrophil neutralization using anti-Ly6G monoclonal antibody showed a significant decrease in tissue damage and an increase in tight junction protein organization. 16S rRNA sequencing on intestinal samples highlighted the role of infiltrated neutrophils in modulating microbial community structure by providing a growth benefit for pathogenic bacteria, such as Enterococcus, and simultaneously causing a significant depletion of commensal bacteria, such as Lactobacillus. Taken together, we provide the first direct evidence that neutrophil infiltration contributes to morphine-induced intestinal tissue damage and gut microbial dysbiosis. Our findings implicate that inhibition of neutrophil infiltration may provide therapeutic benefits against gastrointestinal dysfunctions associated with opioid use.

Histopathologic, phenotypic, and molecular criteria to discriminate low-grade intestinal T-cell lymphoma in cats from lymphoplasmacytic enteritis

BACKGROUND

Differentiation of low-grade intestinal T-cell lymphoma (LGITL) from lymphoplasmacytic enteritis (LPE) in cats is a diagnostic challenge for pathologists.

OBJECTIVE

Characterize histologic, immunohistochemical, and molecular features of LGITL and LPE.

ANIMALS

Forty-four client-owned cats, 22 diagnosed with LGITL and 22 with LPE.

METHODS

Prospective, cohort study. Clinical suspicion of LGITL or LPE was based on persistent gastrointestinal signs, unresponsive to empirical treatments. All cats underwent a standardized diagnostic evaluation, including biopsy (preferentially full-thickness), and were diagnosed with LGITL or LPE after review of clinical, laboratory, sonographic, histologic, immunohistochemical, and clonality results.

RESULTS

A monomorphic lymphocytic population (22/22, 100%) and in-depth mucosal infiltration (15/22, 68%) were hallmarks of LGITL. Epithelial patterns (nests and plaques) were significantly more frequent in LGITL (11/22, 50%) than in LPE (1/22, 5%) cases (P = .001). A CD3+ lymphocytic apical-to-basal gradient was observed in 9/22 (41%) of LGITL vs 1/22 (5%) of LPE cases (P = .004). Most LPE cases (17/18, 94%) featured marked fibrosis in the superficial part of the lamina propria. The Ki-67 20%- and 30%-thresholds discriminated between LGITL and LPE within both the epithelium (specificity >95%) and lamina propria (specificity >95%), respectively. All LGITL cases were CD3+ pSTAT3- and pSTAT5+. T-cell receptor gamma chain gene rearrangements indicated monoclonality in 86% of LGITL cases. Surprisingly, 70% of LPE cases featured monoclonality (40%) or monoclonality on a polyclonal background (30%).

CONCLUSIONS AND CLINICAL IMPORTANCE

We identified new histologic, immunohistochemical, and clonality criteria to distinguish LGITL from LPE.

Enhanced Gut-Homing Dynamics and Pronounced Exhaustion of Mucosal and Blood CD4+ T Cells in HIV-Infected Immunological Non-Responders

Immunological non-responders (INR), a subgroup of people living with HIV (PLHIV) who fail to restore CD4⁺ T cell numbers upon effective antiretroviral treatment, have impaired gut mucosal barrier function and an inferior clinical prognosis compared with immunological responders (IR). The contribution of gut-homing and exhaustion of mucosal T cells to the INR phenotype was previously unknown. Flow cytometry analysis of mononuclear cells from peripheral blood and ileal and colonic lamina propria showed that INR had higher fractions of gut-homing CD4⁺ T cells in blood compared with IR. In addition, gut-homing cells were more likely to display signs of exhaustion in INR. The increased CD4⁺ T cell exhaustion in INR was ubiquitous and not restricted to subpopulations defined by activation, differentiation or regulatory T cell markers. In INR, colon CD4⁺ T cell exhaustion correlated negatively with the fraction of CD4⁺ T cells in the same compartment, this was not apparent in the ileum. The fraction of exhausted mucosal CD4⁺ T cells correlated with I-FABP and REG3α, markers of enterocyte damage. We conclude that alterations of gut-homing and exhaustion of T cells may contribute to impaired gut immune and barrier functions associated with immunological non-response in PLHIV.

T1 Bladder Cancer: Comparison of the Prognostic Impact of Two Substaging Systems on Disease Recurrence and Progression and Suggestion of a Novel Nomogram

Background: The T1 substaging of bladder cancer (BCa) potentially impacts disease progression. The objective of the study was to compare the prognostic accuracy of two substaging systems on the recurrence and progression of primary pathologic T1 (pT1) BCa and to test a nomogram based on pT1 substaging for predicting recurrence-free survival (RFS) and progression-free survival (PFS). Methods: The medical records of 204 patients affected by pT1 BCa were retrospectively reviewed. Substaging was defined according to the depth of lamina propria invasion in T1_a-c and the extension of the lamina propria invasion to T1-microinvasive (T1_m) or T1-extensive (T1_e). Uni- and multivariable Cox regression models evaluated the independent variables correlated with recurrence and progression. The predictive accuracies of the two substaging systems were compared by Harrell's C index. Multivariate Cox regression models for the RFS and PFS were also depicted by a nomogram. Results: The 5-year RFS was 47.5% with a significant difference between T1_c and T1_a (p = 0.02) and between T1_e and T1_m (p < 0.001). The 5-year PFS was 75.9% with a significant difference between T1_c and T1_a (p = 0.011) and between T1_e and T1_m (p < 0.001). Model T1_m-e showed a higher predictive power than T1_a-c for predicting RFS and PFS. In the univariate and multivariate model subcategory T1e, the diameter, location, and number of tumors were confirmed as factors influencing recurrence and progression after adjusting for the other variables. The nomogram incorporating the T1_m-e model showed a satisfactory agreement between model predictions at 5 years and actual observations. Conclusions: Substaging is significantly associated with RFS and PFS for patients affected by T1 BCa and should be included in innovative prognostic nomograms.

Temporal Dynamics of T Helper Populations in the Proximal Small Intestine after Oral Bovine Lactoferrin Administration in BALB/c Mice

Bovine lactoferrin (bLf), a component of milk and a dietary supplement, modulates intestinal immunity at effector and inductor sites. Considering the regional difference in intestinal compartments and the dynamics of local cytokine-producing cells in the gut across time, the aim of this work was to characterize the effects of bLf on the proximal small intestine in a BALB/c murine model of oral administration. Male BALB/c mice were treated with oral bLf vs. saline control as mock by buccal deposition for 28 days. Intestinal secretions were obtained at different time points and cells were isolated from Peyer's patches (PP) and lamina propria (LP) of the proximal small intestine as representative inductor and effector sites, respectively. Total and specific anti-bLF IgA and IgM were determined by enzyme-immuno assay; the percentages of IgA+ and IgM+ plasma cells (PC) and cytokine-producing CD4+ T cells of PP and LP were analyzed by flow cytometry. We found that total and bLf-specific IgA and IgM levels were increased in the intestinal secretions of the bLf group in comparison to mock group and day 0. LP IgA+ PC and IgM+ PC presented an initial elevation on day 7 and day 21, respectively, followed by a decrease on day 28 in comparison to mock. Higher percentages of CD4+ T cells in LP were found in the bLf group. Cytokines-producing CD4+ T cells populations presented a pattern of increases and decreases in the bLf group in both LP and PP. Transforming growth factor beta (TGF-β)+ CD4+ T cells showed higher percentages after bLf administration with a marked peak at day 21 in both LP and PP in comparison to mock-treated mice. Oral bLf exhibits complex immune properties in the proximal small intestine, where temporal monitoring of the inductor and effector compartments reveals patterns of rises and falls of different cell populations. Exceptionally, TGF-β+ CD4+ T cells show consistent higher numbers after bLf intervention across time. Our work suggests that isolated measurements do not show the complete picture of the modulatory effects of oral bLf in immunological sites as dynamic as the proximal small intestine.

Leukocyte numbers and intestinal mucosal morphometrics in horses with no clinical intestinal disease

Healthy horses and other animals have large numbers of resident leukocytes in the intestinal wall, but there is scant information regarding which and how many leukocytes are normally present in the equine intestinal wall. Our aim was to provide a reference range of leukocytes in the intestinal mucosal and submucosal propria of normal horses. We included in our study intestinal tissues from 22 Thoroughbred racehorses with no clinical intestinal disease, which had been euthanized because of catastrophic musculoskeletal injuries. Neutrophils, lymphocytes, eosinophils, macrophages, and plasma cells were counted in 5 random 17,600-µm² areas of villus lamina propria of the duodenum, jejunum, and ileum, and deep lamina propria of the duodenum, jejunum, ileum, right ventral colon, left ventral colon, left dorsal colon, right dorsal colon, and small colon. Other features investigated in the same intestinal segments included villus height and width (small intestine), presence of ciliated protozoa, Paneth cells number, subcryptal leukocyte layers (number of leukocyte layers between the bottom of the crypts and the muscularis mucosae), and submucosal leukocytes. Lymphocytes were the most numerous cells in all segments analyzed, followed by plasma cells, eosinophils, macrophages, and neutrophils. Eosinophil numbers were significantly higher in both lamina propria and submucosa of the large intestine than in the small intestine. The duodenum had shorter and thinner villi than either jejunum or ileum. The data provided from our study will be useful for diagnosticians examining inflammatory processes in the intestinal tract of horses.

Molecular pathways underlying tissue injuries in the bladder with ketamine cystitis

Ketamine cystitis (KC) is a chronic bladder inflammation leading to urinary urgency, frequency, and pain. The pathogenesis of KC is complicated and involves multiple tissue injuries in the bladder. Recent studies indicated that urothelium disruption, lamina propria fibrosis and inflammation, microvascular injury, neuropathological alterations, and bladder smooth muscle (BSM) abnormalities all contribute to the pathogenesis of KC. Ketamine has been shown to induce these tissue injuries by regulating different signaling pathways. Ketamine can stimulate antiproliferative factor, adenosine triphosphate, and oxidative stress to disrupt urothelium. Lamina propria fibrosis and inflammation are associated with the activation of cyclooxygenase-2, nitric oxide synthase, immunoglobulin E, and transforming growth factor β1. Ketamine contributes to microvascular injury via the N-methyl-D aspartic receptor (NMDAR), and multiple inflammatory and angiogenic factors such as tumor necrosis factor α and vascular endothelial growth factor. For BSM abnormalities, ketamine can depress the protein kinase B, extracellular signal-regulated kinase, Cav1.2, and muscarinic receptor signaling. Elevated purinergic signaling also plays a role in BSM abnormalities. In addition, ketamine affects neuropathological alterations in the bladder by regulating NMDAR- and brain-derived neurotrophic factor-dependent signaling. Inflammatory cells also contribute to neuropathological changes via the secretion of chemical mediators. Clarifying the role and function of these signaling underlying tissue injuries in the bladder with KC can contribute to a better understanding of the pathophysiology of this disease and to the design of effective treatments for KC.

Evaluation of the Human Vocal Fold Lamina Propria Development Using Optical Coherence Tomography

OBJECTIVES/HYPOTHESIS

Identifying distinctive features of the vocal fold (VF) during development could have significant clinical implications for treating voice disorders. This study investigates the structural organization of the VF microanatomy across gender and age groups using optical coherence tomography (OCT).

STUDY DESIGN

Prospective clinical trial.

MATERIALS AND METHODS

In vivo OCT images were acquired from 97 patients (58 males and 39 females) aged between 6 weeks and 27 years. All patients showed no signs of vocal fold pathology on endoscopy. Morphological features were extracted from OCT images and statistically compared between age groups. This study was performed at Massachusetts Eye and Ear between 2017 and 2019.

RESULTS

All OCT acquisitions show a stratified microanatomy across age groups, even in newborns suggesting the presence of a superficial lamina propria (SLP) at birth. Furthermore, the optical scattering in the VF lamina propria changes according to age, suggesting subepithelial maturation. Although the epithelium thickness was relatively constant across age groups, the SLP showed a significant linear relationship between age and thickness (P = .016). Furthermore, a significant difference (P = .002) in SLP thickness was found between young adult males and females. The overall thickness of the entire mucosa did not change significantly with age.

CONCLUSION

OCT is a noninvasive imaging modality capable of providing quantitative morphological features to describe the VF development. A stratified structure can be observed in OCT from newborns to young adults. Further investigations could combine OCT, acoustic measurements, and molecular sensitive techniques to provide a complete interpretation of the VF development.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:E2558-E2565, 2021.

High-Fat Diet and Age-Dependent Effects of IgA-Bearing Cell Populations in the Small Intestinal Lamina Propria in Mice

Several studies highlighted that obesity and diabetes reduce immune function. However, changes in the distribution of immunoglobins (Igs), including immunoglobulin-A (IgA), that have an important function in mucosal immunity in the intestinal tract, are unclear. This study aimed to investigate the impaired immune functions in the context of a diet-induced obese murine model via the assessment of the Igs in the intestinal villi. We used mice fed a high-fat diet (HFD) from four to 12 or 20 weeks of age. The distributions of IgA, IgM, and IgG1 were observed by immunohistochemistry. Interestingly, we observed that IgA was immunolocalized in many cells of the lamina propria and that immunopositive cells increased in mice aged 12 to 20 weeks. Notably, mice fed HFD showed a reduced number of IgA-immunopositive cells in the intestinal villi compared to those fed standard chow. Of note, the levels of IgM and IgG1 were also reduced in HFD fed mice. These results provide insights into the impaired mucosal immune function arising from diet-induced obesity and type 2 diabetes.

Sestrin3 enhances macrophage-mediated generation of T helper 1 and T helper 17 cells in a mouse colitis model

Intestinal macrophages participate in the pathogenesis of inflammatory bowel diseases (IBDs) through secreting pro-inflammatory and tissue-damaging factors as well as inducing the differentiation of T helper 1 (Th1) and T helper 17 (Th17) cells. Elucidating the regulatory mechanisms of intestinal macrophage activity in IBDs is important for developing new therapeutic approaches. In the current study, the expression of Sestrins in myeloid cells and lymphocytes in colonic lamina propria (LP) was evaluated in a murine acute colitis model. We found that Sestrin3 was significantly up-regulated in LP macrophages by the colonic LP microenvironment. In the in vitro experiments, lentivirus-mediated Sestrin3 knockdown significantly reduced the production of IL-12 and IL-23 in activated macrophages, in addition to decreasing the expression of classical pro-inflammatory cytokines such as IL-1β, IL-6 and TNF-α. Additionally, Sestrin3 knockdown impaired macrophage-mediated generation of Th1 and Th17 cells from CD4+ T cells, probably through up-regulating the phosphorylation of mechanistic target of rapamycin complex 1 (mTORC1) in macrophages. In the in vivo experiments, adoptive transfer of Sestrin3-deficient macrophages alleviated the generation of Th1 and Th17 cells in the colonic LP and mesenteric lymph nodes. Furthermore, the adoptive transfer mitigated the severity of colitis, as demonstrated by lower production of pro-inflammatory cytokines and fewer tissue lesions in the colon. Our study suggests that Sestrin3 might be crucial for macrophage-mediated generation of pathogenic Th1 and Th17 cells in IBDs.

Intestinal resident macrophages: Multitaskers of the gut

BACKGROUND

Intestinal resident macrophages play a crucial role in homeostasis and have been implicated in numerous gastrointestinal diseases. While historically believed to be largely of hematopoietic origin, recent advances in fate-mapping technology have unveiled the existence of long-lived, self-maintaining populations located in specific niches throughout the gut wall. Furthermore, the advent of single-cell technology has enabled an unprecedented characterization of the functional specialization of tissue-resident macrophages throughout the gastrointestinal tract.

PURPOSE

The purpose of this review was to provide a panorama on intestinal resident macrophages, with particular focus to the recent advances in the field. Here, we discuss the functions and phenotype of intestinal resident macrophages and, where possible, the functional specialization of these cells in response to the niche they occupy. Furthermore, we will discuss their role in gastrointestinal diseases.

The Essential Role of Selenoproteins in the Resolution of Citrobacter rodentium-Induced Intestinal Inflammation

Enteropathogenic Escherichia coli (EPEC) leads to adverse colonic inflammation associated with poor resolution of inflammation and loss of epithelial integrity. Micronutrient trace element selenium (Se) is incorporated into selenoproteins as the 21st amino acid, selenocysteine (Sec). Previous studies have shown that such an incorporation of Sec into the selenoproteome is key for the anti-inflammatory functions of Se in macrophages and other immune cells. An intriguing mechanism underlying the anti-inflammatory and pro-resolving effects of Se stems from the ability of selenoproteins to skew arachidonic acid metabolism from pro-inflammatory mediators, prostaglandin E₂ (PGE₂) toward anti-inflammatory mediators derived from PGD₂, such as 15-deoxy-Δ^{12, 14}- prostaglandin J₂ (15d-PGJ₂), via eicosanoid class switching of bioactive lipids. The impact of Se and such an eicosanoid-class switching mechanism was tested in an enteric infection model of gut inflammation by C. rodentium, a murine equivalent of EPEC. C57BL/6 mice deficient in Se (Se-D) experienced higher mortality when compared to those on Se adequate (0.08 ppm Se) and Se supplemented (0.4 ppm Se) diets following infection. Decreased survival was associated with decreased group 3 innate lymphoid cells (ILC3s) and T helper 17 (Th17) cells in colonic lamina propria of Se-D mice along with deceased expression of epithelial barrier protein Zo-1. Inhibition of metabolic inactivation of PGE₂ by 15-prostaglandin dehydrogenase blocked the Se-dependent increase in ILC3 and Th17 cells in addition to reducing epithelial barrier integrity, as seen by increased systemic levels of FITC-dextran following oral administration; while 15d-PGJ₂ administration in Se-D mice alleviated the effects by increasing ILC3 and Th17 cells. Mice lacking selenoproteins in monocyte/macrophages via the conditional deletion of the tRNA^[Sec] showed increased mortality post infection. Our studies indicate a crucial role for dietary Se in the protection against inflammation following enteric infection via immune mechanisms involving epithelial barrier integrity.

Inherent Immune Cell Variation Within Colonic Segments Presents Challenges for Clinical Trial Design

BACKGROUND AND AIMS

Intestinal biopsy sampling during IBD trials represents a valuable adjunct strategy for understanding drug responses at the tissue level. Given the length and distinctive embryonic origins of the proximal and distal colon, we investigated whether inherent regional differences of immune cell composition could introduce confounders when sampling different disease stages, or pre/post drug administration. Here, we capitalise on novel mass cytometry technology to perform deep immunophenotyping of distinct healthy colonic segments, using the limited numbers of biopsies that can be harvested from patients.

METHODS

Biopsies [2.8 mm] were collected from the caecum, transverse colon, descending colon, and rectum of normal volunteers. Intestinal leukocytes were isolated, stained with a panel of 37 antibodies, and mass cytometry data acquired.

RESULTS

Site-specific patterns of leukocyte localisation were observed. The proximal colon featured increased CD8+ T cells [particularly resident memory], monocytes, and CD19+ B cells. Conversely, the distal colon and rectum tissues exhibited enrichment for CD4+ T cells and antibody-secreting cells. The transverse colon displayed increased abundance of both γδ T cells and NK cells. Subsets of leukocyte lineages also displayed gradients of expression along the colon length.

CONCLUSIONS

Our results show an inherent regional immune cell variation within colonic segments, indicating that regional mucosal signatures must be considered when assessing disease stages or the prospective effects of trial drugs on leukocyte subsets. Precise protocols for intestinal sampling must be implemented to allow for the proper interpretation of potential differences observed within leukocyte lineages present in the colonic lamina propria.

The NLRP3 inflammasome mediates DSS-induced intestinal inflammation in Nod2 knockout mice

Crohn’s disease (CD) is a chronic disorder of the gastrointestinal tract characterized by inflammation and intestinal epithelial injury. Loss of function mutations in the intracellular bacterial sensor NOD2 are major risk factors for the development of CD. In the absence of robust bacterial recognition by NOD2 an inflammatory cascade is initiated through alternative PRRs leading to CD. In the present study, MCC950, a specific small molecule inhibitor of NLR pyrin domain-containing protein 3 (NLRP3), abrogated dextran sodium sulfate (DSS)-induced intestinal inflammation in Nod2^−/− mice. NLRP3 inflammasome formation was observed at a higher rate in NOD2-deficient small intestinal lamina propria cells after insult by DSS. NLRP3 complex formation led to an increase in IL-1β secretion in both the small intestine and colon of Nod2ko mice. This increase in IL-1β secretion in the intestine was attenuated by MCC950 leading to decreased disease severity in Nod2ko mice. Our work suggests that NLRP3 inflammasome activation may be a key driver of intestinal inflammation in the absence of functional NOD2. NLRP3 pathway inhibition can prevent intestinal inflammation in the absence of robust NOD2 signaling.

Aerodynamically driven phonation of individual vocal folds under general anesthesia in canines

OBJECTIVES/HYPOTHESIS

We previously developed an instrument called the Aerodynamic Vocal Fold Driver (AVFD) for intraoperative magnified assessment of vocal fold (VF) vibration during microlaryngoscopy under general anesthesia. Excised larynx testing showed that the AVFD could provide useful information about the vibratory characteristics of each VF independently. The present investigation expands those findings by testing new iterations of the AVFD during microlaryngoscopy in the canine model.

STUDY DESIGN

Animal model.

METHODS

The AVFD is a handheld instrument that is positioned to contact the phonatory mucosa of either VF during microlaryngoscopy. Airflow delivered through the AVFD shaft to the subglottis drives the VF into phonation-like vibration, which enables magnified observation of mucosal-wave function with stroboscopy or high-speed video. AVFD-driven phonation was tested intraoperatively (n = 26 VFs) using either the original instrument design or smaller and larger versions three-dimensionally printed from a medical grade polymer. A high-fidelity pressure sensor embedded within the AVFD measured VF contact pressure. Characteristics of individual VF phonation were compared with typical two-fold phonation and compared for VFs scarred by electrocautery (n = 4) versus controls (n = 22).

RESULTS

Phonation was successful in all 26 VFs, even when scar prevented conventional bilateral phonation. The 15-mm-wide AVFD fits best within the anteroposterior dimension of the musculo-membranous VF, and VF contact pressure correlated with acoustic output, driving pressures, and visible modes of vibration.

CONCLUSIONS

The AVFD can reveal magnified vibratory characteristics of individual VFs during microlaryngoscopy (e.g., without needing patient participation), potentially providing information that is not apparent or available during conventional awake phonation, which might facilitate phonosurgical decision making.

LEVEL OF EVIDENCE

NA Laryngoscope, 130: 1980-1988, 2020.

Acute Appendicitis or Lymphoid Hyperplasia: How to Distinguish More Safely?

PURPOSE

Lymphoid hyperplasia can be an important mimicker of acute appendicitis by creating a non-compressible appendix more than 6 mm in diameter. The aim of this study was to evaluate methods of distinguishing lymphoid hyperplasia and appendicitis on the basis of sonography, lamina propria thickness, and Alvarado scoring.

METHODS

This retrospective study included 259 patients (142 appendicitis, 117 lymphoid hyperplasia). The US (ultrasound) reports of the patients were reviewed and the maximum diameter of the appendix, the presence or absence of increased echogenicity of the surrounding pericaecal fat, local fluid collection, the presence of reactive lymph nodes in the periappendiceal area, and mural hyperemia within the appendix were recorded.

RESULTS

The use of additional sonographic criteria, lamina propria thickness (≤1 mm is indicative for appendicitis), or Alvarado scoring (>6 mm is indicative for appendicitis) provided a true-positive diagnosis for acute appendicitis.

CONCLUSION

The presence of local fluid collection in the periappendiceal area and a lamina propria thickness ≤ 1 mm are the most successful parameters for distinguishing appendicitis from lymphoid hyperplasia.

An Immunohistochemical Study of Gastric Mucosa and Critical Review Indicate that the Subepithelial Telocytes are Prelymphatic Endothelial Cells

Background and Objectives: There are only a few studies regarding gut subepithelial telocytes (TCs). The telopodes, namely peculiar TCs’ prolongations described on two-dimensional cuts, are not enough to differentiate this specific cell type. Subepithelial TCs were associated with the intestinal stem niche but a proper differential diagnosis with lymphatic endothelial cells (LECs) was not performed. In this study, we will also critically review studies suggesting that distinctive TCs could be positioned within the lamina propria. Materials and Methods: We performed an immunohistochemical study of human gastric mucosa to test the expression of D2-40, the lymphatic marker, as well as that of CD31, CD34, CD44, CD117/c-kit, α-smooth muscle actin (α-SMA) and vimentin in the gastric subepithelial niche. Results: The results support the poorly investigated anatomy of intramural gastric lymphatics, with circumferential collectors located on both sides of the muscularis mucosae (mucosal and then submucosal) and myenteric collectors in the muscularis propria. We also found superficial epithelial prelymphatic channels bordered by D2-40+ but CD31–TC-like cells. Deep epithelial lymphatic collectors drain in collectors within the lamina propria. Blood endothelial cells expressed CD31, CD34, CD44, and vimentin. Conclusions: Therefore, the positive diagnosis of TC for subepithelial CD34+ cells should be regarded with caution, as they could also be artefacts, resulting from the two-dimensional examination of three dimensional structures, or as LECs. Lymphatic markers should be routinely used to discriminate TCs from LECs.

Effect of pirfenidone injection on ferret vocal fold scars: A preliminary in vivo study

OBJECTIVES

This study examined the antifibrotic effect of pirfenidone (PFD), which has received regulatory approval in the United States and Japan for treatment of idiopathic pulmonary fibrosis, on the scarred ferret vocal fold (VF) in vivo.

METHODS

Eight male ferrets were divided into two groups: saline and PFD. All animals underwent unilateral scarring under anesthesia. The right VF was electrocauterized with ablation of the entire lamina propria. PFD (1.0 mg/mL) or saline injections into right-side scarred VFs were performed (under an operating microscope) 4 weeks later. After an additional 4 weeks, the larynges were harvested for histological analysis. Prior to harvesting, the ferrets were re-anesthetized, and the VFs were observed and recorded using a rigid video laryngoscope. We immunohistochemically evaluated the expression of collagen types I and III, alpha-smooth muscle actin (α-SMA), and fibronectin in the entire lamina propria. We compared the affected areas (calculated using ImageJ software) between the treated (right) and untreated (left) sides within the same animals and between groups.

RESULTS

Collagen type I (P = 0.0021) and α-SMA (P = 0.0021) expression levels were lower in the PFD group, but the collagen type III and fibronectin levels did not differ significantly between the two groups.

CONCLUSION

PFD injection into the scarred VF is a potentially promising novel antifibrotic treatment.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:726-731, 2020.

Nerve sprouting and neurogenic inflammation characterize the neurogenic detrusor overactive bladder of patients no longer responsive to drug therapies

Urothelium and Lamina Propria (LP) are considered an integrate sensory system which is able to control the detrusor activity. Complete supra-sacral spinal cord lesions cause Neurogenic Detrusor Overactivity (NDO) whose main symptoms are urgency and incontinence. NDO therapy at first consists in anti-muscarinic drugs; secondly, in intra-vesical injection of botulinum toxin. However, with time, all the patients become insensitive to the drugs and decide for cystoplastic surgery. With the aim to get deeper in both NDO and drug's efficacy lack pathogenesis, we investigated the innervation, muscular and connective changes in NDO bladders after surgery by using morphological and quantitative methodologies. Bladder innervation showed a significant global loss associated with an increase in the nerve endings located in the upper LP where a neurogenic inflammation was also present. Smooth muscle cells (SMC) anomalies and fibrosis were found in the detrusor. The increased innervation in the ULP is suggestive for a sprouting and could condition NDO evolution and drug efficacy length. Denervation might cause the SMC anomalies responsible for the detrusor altered contractile activity and intra-cellular traffic and favour the appearance of fibrosis. Inflammation might accelerate these damages. From the clinical point of view, an early anti-inflammatory treatment could positively influence the disease fate.

Contribution of Wound-Associated Cells and Mediators in Orchestrating Gastrointestinal Mucosal Wound Repair

The gastrointestinal mucosa, structurally formed by the epithelium and lamina propria, serves as a selective barrier that separates luminal contents from the underlying tissues. Gastrointestinal mucosal wound repair is orchestrated by a series of spatial and temporal events that involve the epithelium, recruited immune cells, resident stromal cells, and the microbiota present in the wound bed. Upon injury, repair of the gastrointestinal barrier is mediated by collective migration, proliferation, and subsequent differentiation of epithelial cells. Epithelial repair is intimately regulated by a number of wound-associated cells that include immune cells and stromal cells in addition to mediators released by luminal microbiota. The highly regulated interaction of these cell types is perturbed in chronic inflammatory diseases that are associated with impaired wound healing. An improved understanding of prorepair mechanisms in the gastrointestinal mucosa will aid in the development of novel therapeutics that promote mucosal healing and reestablish the critical epithelial barrier function.

Saving Problematic Mucosae: SPMs in Intestinal Mucosal Inflammation and Repair

The intestinal mucosa serves as a highly selective barrier that allows the absorption of nutrients and water while restricting microbiota access to tissues. This barrier is compromised in inflammatory conditions such as infectious colitis and inflammatory bowel disease (IBD). In response to mucosal injury, there is a temporal recruitment of leukocytes that crosstalk with epithelial cells to orchestrate repair. Specialized pro-resolving mediators (SPMs) play an important role in the resolution of inflammation and epithelial repair. SPMs actively promote resolution of inflammation by contributing to the clearance of neutrophils, stimulating efferocytosis, and promoting epithelial repair. SPMs have potential to serve as targeted therapeutic agents to be used in adjuvant therapy to promote resolution of inflammation and epithelial repair in chronic inflammatory diseases.

Matrix Metalloproteinase-1 and Acid Phosphatase in the Degradation of the Lamina Propria of Eruptive Pathway of Rat Molars

The comprehension of dental pathogenesis and disorders derived from eruption failure requires a deep understanding of the molecular mechanisms underlying normal tooth eruption. As intense remodelling is needed during tooth eruption, we hypothesize that matrix metalloproteinase-1 (MMP-1) and acid phosphatase (ACP) play a role in the eruptive pathway degradation. We evaluated MMP-1-immunoexpression and the collagen content in the lamina propria at different eruptive phases. Immunohistochemistry and ultrastructural cytochemistry for detection of ACP were also performed. In the maxillary sections containing first molars of 9-, 11-, 13-, and 16-day-old rats, the birefringent collagen of eruptive pathway was quantified. MMP-1 and ACP-2 immunohistochemical reactions were performed and the number of MMP-1-immunolabelled cells was computed. Data were analyzed by one-way ANOVA and Tukey post-test (p ≤ 0.05). ACP cytochemistry was evaluated in specimens incubated in sodium β-glycerophosphate. In the eruptive pathway of 13- and 16-day-old rats, the number of MMP-1-immunolabelled cells increased concomitantly to reduction of collagen in the lamina propria. Enhanced ACP-2-immunolabelling was observed in the lamina propria of 13- and 16-day-old rats. Fibroblasts and macrophages showed lysosomes and vacuoles containing fragmented material reactive to ACP. MMP-1 degrades extracellular matrix, including collagen fibers, being responsible for the reduction in the collagen content during tooth eruption. The enhanced ACP activity at the mucosal penetration stage indicates that this enzyme plays a role in the degradation of remnant material, which is engulfed by macrophages and fibroblasts of the eruptive pathway. Therefore, enzymatic failure in the eruptive pathway may disturbs tooth eruption.

An ex vivo bladder model with detrusor smooth muscle removed to analyse biologically active mediators released from the suburothelium

KEY POINTS

Studies of urothelial cells, bladder sheets or lumens of filled bladders have suggested that mediators released from urothelium into suburothelium (SubU)/lamina propria (LP) activate mechanisms controlling detrusor excitability. None of these approaches, however, has enabled direct assessment of availability of mediators at SubU/LP during filling. We developed an ex vivo mouse bladder preparation with intact urothelium and SubU/LP but no detrusor, which allows direct access to the SubU/LP surface of urothelium during filling. Pressure-volume measurements during filling demonstrated that bladder compliance is governed primarily by the urothelium. Measurements of purine mediators in this preparation demonstrated asymmetrical availability of purines in lumen and SubU/LP, suggesting that interpretations based solely on intraluminal measurements of mediators may be inaccurate. The preparations are suitable for assessments of release, degradation and transport of mediators in SubU/LP during bladder filling, and are superior to experimental approaches previously used for urothelium research.

ABSTRACT

The purpose of this study was to develop a decentralized (ex vivo) detrusor smooth muscle (DSM)-denuded mouse bladder preparation, a novel model that enables studies on availability of urothelium-derived mediators at the luminal and anti-luminal aspects of the urothelium during filling. Urinary bladders were excised from C57BL6/J mice and the DSM was removed by fine-scissor dissection without touching the mucosa. Morphology and cell composition of the preparation wall, pressure-volume relationships during filling, and fluorescent dye permeability of control, protamine sulfate- and lipopolysaccharide-treated denuded bladders were characterized. The preparation wall contained intact urothelium and suburothelium (SubU)/lamina propria (LP) and lacked the DSM and the serosa. The utility of the model for physiological research was validated by measuring release, metabolism and transport of purine mediators at SubU/LP and in bladder lumen during filling. We determined asymmetrical availability of purines (e.g. ATP, ADP, AMP and adenosine) in lumen and at SubU/LP during filling, suggesting differential mechanisms of release, degradation and bilateral transurothelial transport of purines during filling. Some observations were validated in DSM-denuded bladder of the cynomolgus monkey (Macaca fascicularis). The novel model was superior to current models utilized to study properties of the urothelium (e.g. cultured urothelial cells, bladder mucosa sheets mounted in Ussing chambers or isolated bladder strips in organ baths) in that it enabled direct access to the vicinity of SubU/LP during authentic bladder filling. The model is particularly suitable for understanding local mechanisms of urothelium-DSM connectivity and for broad understanding of the role of urothelium in regulating continence and voiding.

Implementation of Mass Cytometry as a Tool for Mechanism of Action Studies in Inflammatory Bowel Disease

Background

Novel therapeutics for inflammatory bowel disease (IBD) are under development, yet mechanistic readouts at the tissue level are lacking. Techniques to assess intestinal immune composition could represent a valuable tool for mechanism of action (MOA) studies of novel drugs. Mass cytometry enables analysis of intestinal inflammatory cell infiltrate and corresponding molecular fingerprints with unprecedented resolution. Here, we aimed to optimize the methodology for isolation and cryopreservation of cells from intestinal tissue to allow for the potential implementation of mass cytometry in MOA studies.

Methods

We investigated key technical issues, including minimal tissue requirements, cell isolation protocols, and cell storage, using intestinal biopsies and peripheral blood from healthy individuals. High-dimensional mass cytometry was employed for the analyses of biopsy-derived intestinal cellular subsets.

Results

Dithiothreitol and mechanical dissociation decreased epithelial cell contamination and allowed for isolation of adequate cell numbers from 2 to 4 colonic or ileal biopsies (6 × 104±2 × 104) after a 20-minute collagenase digestion, allowing for reliable detection of most major immune cell subsets. Biopsies and antibody-labeled mononuclear cells could be cryopreserved for later processing and acquisition (viability > 70%; P < 0.05).

Conclusions

Mass cytometry represents a unique tool for deep immunophenotyping intestinal cell composition. This technique has the potential to facilitate analysis of drug actions at the target tissue by identifying specific cellular subsets and their molecular signatures. Its widespread implementation may impact not only IBD research but also other gastrointestinal conditions where inflammatory cells play a role in pathogenesis.

Mucosal immune system of the gastrointestinal tract: maintaining balance between the good and the bad

The gastrointestinal tract (GI tract) is a unique organ inhabited by a range of commensal microbes, while also being exposed to an overwhelming load of antigens in the form of dietary antigens on a daily basis. The GI tract has dual roles in the body, in that it performs digestion and uptake of nutrients while also carrying out the complex and important task of maintaining immune homeostasis, i.e., keeping the balance between the good and the bad. It is equally important that we protect ourselves from reacting against the good, meaning that we stay tolerant to harmless food, commensal bacteria and self-antigens, as well as react with force against the bad, meaning induction of immune responses against harmful microorganisms. This complex task is achieved through the presence of a highly efficient mucosal barrier and a specialized multifaceted immune system, made up of a large population of scattered immune cells and organized lymphoid tissues termed the gut-associated lymphoid tissue (GALT). This review provides an overview of the primary components of the human mucosal immune system and how the immune responses in the GI tract are coordinated and induced.

Isolation and high-dimensional phenotyping of gastrointestinal immune cells

The gastrointestinal immune system plays a pivotal role in the host relationship with food antigens, the homeostatic microbiome and enteric pathogens. Here, we describe how to collect and process liver and intestinal samples to efficiently isolate and analyse resident immune cells. Furthermore, we describe a step-by-step methodology showing how to high-dimensionally immunophenotype resident leucocytes using cytometry by time-of-flight, providing a well-characterized antibody platform that allows the identification of every leucocyte subset simultaneously. This protocol also includes instructions to purify and cultivate primary murine hepatocytes, a powerful tool to assess basic cell biology and toxicology assays. Gut and liver samples from the same mouse can be collected, processed and stained in less than 6 hr. This protocol enables the recovery of several populations of purified and viable immune cells from solid and fibrous organs, preventing unwanted loss of adherent cells during isolation.

5-HT2A receptor enhancement of contractile activity of the porcine urothelium and lamina propria

OBJECTIVES

To examine the effect of 5-hydroxytryptamine (5-HT; serotonin) on the contractile properties of the urothelium and lamina propria, as a better understanding of bladder physiology might aid the development of new treatments.

METHODS

Strips of porcine urothelium and lamina propria were suspended in gassed Krebs-bicarbonate solution, and cumulative concentration-response curves for 5-HT were generated in the absence and presence of 5-HT antagonists, Nω-nitro-l-arginine and indomethacin. Responses to α-methyl-5-HT were also examined.

RESULTS

Strips of urothelium/lamina propria developed spontaneous contractions, whereas the addition of 5-HT induced concentration-dependent increases in contractile tone with maximal contractions of 50.43 ± 2.78 mN/g tissue weight (n = 100). Tonic contractions to 5-HT were unchanged in the presence of Nω-nitro-l-arginine (100 μmol/L) or indomethacin (5 μmol/L). Selective concentrations of the antagonists methiothepin (5-HT_1&2 , 100 nmol/L), RS102221 (5-HT_2C , 30 nmol/L), ondansetron (5-HT₃ , 30 nmol/L), GR113808, (5-HT₄ , 100 nmol/L), SB699551 (5-HT₅ , 10 nmol/L), SB399885 (5-HT₆ , 100 nmol/L) and SB269970 (5-HT₇ , 10 nmol/L) did not influence responses to 5-HT. However, the 5-HT_2A antagonist, ketanserin (30-300 μmol/L), caused a shift of the 5-HT curve yielding an affinity estimate of 7.9.

CONCLUSIONS

The results show that contractile responses of the urothelium/lamina propria to 5-HT are predominantly mediated through the 5-HT_2A receptor.

Gut microbiota amplifies host-intrinsic conversion from the CD8 T cell lineage to CD4 T cells for induction of mucosal immune tolerance

Microbiota has been shown to promote tolerogenic differentiation of T lymphocytes. It remains unclear to what extent microbiota triggers de novo re-programming or amplify pre-existing plasticity intrinsic to T cells. In a study with mouse models to track the clonal fate of CD4 and CD8 T cells, we discovered that CD8 T cells converted to MHC class I-restricted CD4 T cells without regard to selfness of their antigen specificity. In mesenteric lymph nodes (MLN), CD8 T cells converted to CD4(+)Foxp3(+) regulatory T (Treg) cells which were enriched in the large intestine lamina propria (LILP) and suppressed chemical- or immune-mediated inflammatory damage. In germ-free conditions, the converted CD4 populations were present in MLN, but absent in LILP. Therefore, an intrinsic plasticity in the host was amplified by the gut microbiota, leading to selfless tolerance induction in the intestinal mucosa. The findings may be relevant to HIV infection, cancer and autoimmune disorders.

Translocation of microbes and changes of immunocytes in the gut of rapid- and slow-progressor Chinese rhesus macaques infected with SIVmac239

Human/simian immunodeficiency virus (HIV/SIV) infection can cause severe depletion of CD4(+) T cells in both plasma and mucosa; it also results in damage to the gut mucosa barrier, which makes the condition more conducive to microbial translocation. In this study, we used SIV-infected Chinese rhesus macaques to quantify the extent of microbial translocation and the function of immune cells in the entire gastrointestinal tract and to compare their differences between rapid and slow progressors. The results showed that in the slow progressors, microbial products translocated considerably and deeply into the lamina propria of the gut; the tissue macrophages had no significant differences compared with the rapid progressors, but there was a slightly higher percentage of mucosal CD8(+) T cells and a large amount of extracellular microbial products in the lamina propria of the intestinal mucosa of the slow progressors. The data suggested that although microbial translocation increased markedly, the mucosal macrophages and CD8(+) T cells were insufficient to clear the infiltrated microbes in the slow progressors. Also, therapies aimed at suppressing the translocation of microbial products in the mucosa could help to delay the progression of SIV disease.

Apoptosis and reduced microvascular density of the lamina propria during tooth eruption in rats

During tooth eruption, structural and functional changes must occur in the lamina propria to establish the eruptive pathway. In this study, we evaluate the structural changes that occur during lamina propria degradation and focus these efforts on apoptosis and microvascular density. Fragments of maxilla containing the first molars from 9-, 11-, 13- and 16-day-old rats were fixed, decalcified and embedded in paraffin. The immunohistochemical detection of vascular endothelial growth factor (VEGF), caspase-3 and MAC387 (macrophage marker), and the TUNEL method were applied to the histological molar sections. The numerical density of TUNEL-positive cells and VEGF-positive blood vessel profiles were also obtained. Data were statistically evaluated using a one-way anova with the post-hoc Kruskal-Wallis or Tukey test and a significance level of P ≤ 0.05. Fragments of maxilla were embedded in Araldite for analysis under transmission electron microscopy (TEM). TUNEL-positive structures, fibroblasts with strongly basophilic nuclei and macrophages were observed in the lamina propria at all ages. Using TEM, we identified processes of fibroblasts or macrophages surrounding partially apoptotic cells. We found a high number of apoptotic cells in 11-, 13- and 16-day-old rats. We observed VEGF-positive blood vessel profiles at all ages, but a significant decrease in the numerical density was found in 13- and 16-day-old rats compared with 9-day-old rats. Therefore, the establishment of the eruptive pathway during the mucosal penetration stage depends on cell death by apoptosis, the phagocytic activity of fibroblasts and macrophages, and a decrease in the microvasculature due to vascular cell death. These data point to the importance of vascular rearrangement and vascular neoformation during tooth eruption and the development of oral mucosa.

Alterations in extracellular matrix composition in the aging larynx

OBJECTIVE

To study by immunohistochemistry the alterations of collagens I, III, IV, and V and elastin in the aging process of the human larynx.

STUDY DESIGN

Cadaver study.

SETTING

Universidade Estadual Paulista, Botucatu Medical School, São Paulo State University (UNESP), Brazil.

SUBJECTS AND METHODS

Thirty vocal folds were obtained at autopsy from 10 adult men (aged 30 to 50 years) and 20 geriatric men (10 aged 60 to 75 years and 10 aged >75 years). Mid membranous vocal fold slides were subjected to immunohistochemical reactions. Digital imaging software (ImageJ) was used to quantify the increase in brownish staining of the lamina propria structures of vocal folds, from superficial to deep layers.

RESULTS

There was an increase of collagen I and III immunoexpression in the elderly larynges, in both layers. Collagens IV and V were immunoexpressed in the vessels endothelium of the lamina propria and in the basement membrane. The immunoexpression of elastin decreased in the elderly larynges, in both lamina propria layers of the vocal folds.

CONCLUSION

A clear increase of collagens I and III and a decrease of elastic fibers were observed in the lamina propria of vocal folds. The concentration of collagens IV and V was the same across age groups. These findings suggest that as men age, the density of the extracellular matrix increases, brought about by an increase in collagen, while the loss of elastin results in decreased viscoelasticity.

Intestinal dendritic cells in the regulation of mucosal immunity

The intestine presents a huge surface area to the outside environment, a property that is of critical importance for its key functions in nutrient digestion, absorption, and waste disposal. As such, the intestine is constantly exposed to dietary and microbial-derived foreign antigens, to which immune cells within the mucosa must suitably respond to maintain intestinal integrity, while also providing the ability to mount effective immune responses to potential pathogens. Dendritic cells (DCs) are sentinel immune cells that play a central role in the initiation and differentiation of adaptive immune responses. In the intestinal mucosa, DCs are located diffusely throughout the intestinal lamina propria, within gut-associated lymphoid tissues, including Peyer's patches and smaller lymphoid aggregates, as well as in intestinal-draining lymph nodes, including mesenteric lymph nodes. The recognition that dietary nutrients and microbial communities in the intestine influence both mucosal and systemic immune cell development and function as well as immune-mediated disease has led to an explosion of literature in mucosal immunology in recent years and a growing interest in the functionality of intestinal DCs. In the current review, we discuss recent findings from our group and others that have provided important insights regarding murine and human intestinal lamina propria DCs and highlighted marked developmental and functional heterogeneity within this compartment. A thorough understanding of the role these subsets play in the regulation of intestinal immune homeostasis and inflammation will help to define novel strategies for the treatment of intestinal pathologies and contribute to improved rational design of mucosal vaccines.