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Introduction:  "Tuft" cells, also known as brush or caveolated cells, are characteristically fusiform shaped, with a distinct apical "tuft" of microvilli extending into the lumen. Double cortin-like kinase 1 (DCLK1) is a microtubule kinase and is a specific marker of intestinal tuft cells. DCLK1-positive tuft cells have been shown to play a key role in gastrointestinal chemosensation, inflammation, and neurotransmission. DCLK1 and Choline acetyltransferase (ChAT), the enzymes responsible for acetylcholine production, are reported to be coexpressed within the gastrointestinal tract. We designed this study to investigate the hypothesis that DCLK1 gene expression is altered in Hirschsprung's disease (HSCR).Materials and Methods:  HSCR tissue specimens (n = 6) were collected at the time of pull-through surgery, while control samples were obtained at the time of colostomy closure in patients with imperforate anus (n = 6). Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was undertaken to quantify DCLK1 gene expression, and immunolabeling of DCLK1-positive tuft cells was visualized using confocal microscopy.Results:  qRT-PCR analysis revealed significant downregulation of the DCLK1 gene in both aganglionic and ganglionic HSCR specimens compared with controls (p < 0.05). Confocal microscopy revealed DCLK1-positive tuft cell expression within the colonic mucosa, with a reduction in expression in both aganglionic and ganglionic HSCR colon compared with controls.Conclusion:  DCLK1 is significantly downregulated in HSCR colon, suggesting a role for tuft cells in cholinergic neurotransmission of the distal colon. The marked decrease in DCLK1 expression within ganglionic specimens highlights the physiologically abnormal nature of this segment in HSCR patients. [ABSTRACT FROM AUTHOR]

Aim Of the Study: Potassium (K+) channels with a two-pore domain (K2P) are a large family of hyperpolarising ion channels which play a key role in cell excitability. This family comprises three members: TREK-1, TREK-2 and TRAAK. TRAAK channels have previously been reported to be expressed in murine enteric ganglia. To date, no data exist regarding TRAAK channel expression in the human colon. Thus, we designed this study to investigate TRAAK gene expression in the normal human colon and in Hirschsprung's disease (HSCR).Methods: HSCR tissue specimens (n = 6) were collected at the time of pull-through surgery, while control samples were obtained at the time of colostomy closure in patients with imperforate anus (n = 6). qRT-PCR analysis was undertaken to quantify TRAAK gene expression, and immunolabelling of TRAAK proteins was visualized using confocal microscopy.Main Results: Confocal microscopy revealed TRAAK protein expression within both neurons and interstitial cells of Cajal in the myenteric plexus, with a reduction in both ganglionic HSCR colon and aganglionic HSCR colon, compared to controls. qRT-PCR analysis revealed a significant downregulation of the TRAAK gene in both aganglionic and ganglionic HSCR specimens compared to controls (p < 0.05).Conclusions: TRAAK gene expression is significantly downregulated in HSCR colon, suggesting a role for these ion channels in colonic neurotransmission. TRAAK downregulation within ganglionic specimens highlights the dysfunctional nature of ganglia in this region. [ABSTRACT FROM AUTHOR]

Purpose: Voltage-gated potassium ion channels have long been implicated in gastrointestinal motility. Recent studies have highlighted the role of voltage-gated channel subfamily G member 3 (KCNG3) and 4 (KCNG4) genes in the electrical functioning of interstitial cells of Cajal and PDGFRα+ cells of the mouse colon. We designed this study to investigate KCNG3 and KCNG4 expression in the normal human colon and in Hirschsprung's disease (HSCR).Methods: HSCR tissue specimens (n = 6) were collected at the time of pull-through surgery, while control samples were obtained at the time of colostomy closure in patients with imperforate anus (n = 6). qRT-PCR analysis was undertaken to quantify KCNG3 and KCNG4 gene expression, and immunolabelling of KCNG3 and KCNG4 proteins was visualized using confocal microscopy.Results: qRT-PCR analysis revealed significant downregulation of the KCNG3 and KCNG4 genes in both aganglionic and ganglionic HSCR specimens compared to controls (p < 0.05). Confocal microscopy revealed KCNG3 and KCNG4 expression within neurons, ICC and PDGFRα+ cells of the myenteric plexus and smooth muscle layers, with a reduction in both proteins in aganglionic and ganglionic HSCR colon compared to controls.Conclusion: KCNG3 and KCNG4 gene expression is significantly downregulated in HSCR colon, suggesting a role for these genes in colonic motility. KCNG3 and KCNG4 downregulation within ganglionic specimens highlights the physiologically abnormal nature of this segment in HSCR patients. [ABSTRACT FROM AUTHOR]

Purpose: Smooth muscle cells are electrically coupled to ICC and PDGFRα+ cells, to regulate smooth muscle contraction. Recent studies have reported that the voltage-gated sodium channel type 1β (Scn1b), and the chloride channel subunit, Fxyd1, are highly expressed by both ICC and PDGFRα+ cells in the mouse colon. We designed this study to investigate the expression of the Scn1b and Fxyd1 genes in the normal human colon and in HSCR.Methods: HSCR tissue specimens (n = 6) were collected at the time of pull-through surgery, while control samples were obtained at the time of colostomy closure in patients with imperforate anus (n = 6). qRT-PCR analysis was undertaken to quantify Scn1b and Fxyd1 gene expression, and immunolabelling of Scn1b and Fxyd1 proteins were visualized using confocal microscopy.Results: qRT-PCR analysis revealed significant downregulation of Scn1b and Fxyd1 genes in both aganglionic and ganglionic HSCR specimens compared to controls (p < 0.05). Confocal microscopy revealed a reduction in Scn1b and Fxyd1 protein expression in both aganglionic and ganglionic HSCR colon compared to controls.Conclusion: Scn1b and Fxyd1 expression was significantly downregulated in HSCR colon. These results add to mounting evidence suggesting that the pulled-through ganglionic segment of bowel in these patients is abnormal, despite the presence of ganglion cells. [ABSTRACT FROM AUTHOR]