Interstitial cells of Cajal: clinical relevance in pediatric gastrointestinal motility disorders

Interstitial cells of Cajal (ICCs) are pacemaker cells of gastrointestinal motility that generate and transmit electrical slow waves to smooth muscle cells in the gut wall, thus inducing phasic contractions and coordinated peristalsis. Traditionally, tyrosine-protein kinase Kit (c-kit), also known as CD117 or mast/stem cell growth factor receptor, has been used as the primary marker of ICCs in pathology specimens. More recently, the Ca2+-activated chloride channel, anoctamin-1, has been introduced as a more specific marker of ICCs. Over the years, various gastrointestinal motility disorders have been described in infants and young children in which symptoms of functional bowel obstruction arise from ICC-related neuromuscular dysfunction of the colon and rectum. The current article provides a comprehensive overview of the embryonic origin, distribution, and functions of ICCs, while also illustrating the absence or deficiency of ICCs in pediatric patients with Hirschsprung disease intestinal neuronal dysplasia, isolated hypoganglionosis, internal anal sphincter achalasia, and congenital smooth muscle cell disorders such as megacystis microcolon intestinal hypoperistalsis syndrome.

Oscillating calcium signals in smooth muscle cells underlie the persistent basal tone of internal anal sphincter

A persistent basal tone in the internal anal sphincter (IAS) is essential for keeping the anal canal closed and fecal continence; its inhibition via the rectoanal inhibitory reflex (RAIR) is required for successful defecation. However, cellular signals underlying the IAS basal tone remain enigmatic. Here we report the origin and molecular mechanisms of calcium signals that control the IAS basal tone, using a combination approach including a novel IAS slice preparation that retains cell arrangement and architecture as in vivo, 2-photon imaging, and cell-specific gene-modified mice. We found that IAS smooth muscle cells generate two forms of contractions (i.e., phasic and sustained contraction) and Ca2+ signals (i.e., synchronized Ca2+ oscillations [SCaOs] and asynchronized Ca2+ oscillations [ACaOs]) that last for hours. RyRs, TMEM16A, L-type Ca2+ channels, and gap junctions are required for SCaOs, which account for phasic contraction and 75% of sustained contraction. Nevertheless, only RyRs are required for ACaOs, which contribute 25% of sustained contraction. Nitric oxide, the primary neurotransmitter mediating the RAIR, blocks both types of Ca2+ signals, leading to IAS's full relaxation. Our results show that the oscillating nature of Ca2+ signals generates and maintains the basal tone without causing cytotoxicity to IAS. Our study provides insight into fecal continence and normal defecation.

The transcriptome of anal papillae of Aedes aegypti reveals their importance in xenobiotic detoxification and adds significant knowledge on ion, water and ammonia transport mechanisms

The anal papillae of mosquito larvae are osmoregulatory organs in direct contact with the external aquatic environment that actively sequester ions and take up water in dilute freshwater. In the disease vector Aedes aegypti mechanisms of ion, water and ammonia transport have only been partially resolved. Furthermore, A. aegypti larvae are known to reside in high ammonia sewage and high salt brackish waters, and understanding of anal papillae function in these conditions is in its infancy. The objective of this study was to identify the complement of ion and water transport genes expressed by the anal papillae of freshwater larvae by sequencing their transcriptome, and comparing their expression in anal papillae of larvae abruptly transferred to brackish water for 24 h. Results identified a number of ion and water transport proteins, ammonia detoxifying enzymes, a full suite of xenobiotic detoxifying enzymes and transporters, and G-protein coupled receptors of specific hormones. We identified a marked increase in transcript and protein abundance of aquaporin AaAQP2 in the anal papillae with abrupt transfer to brackish water. We present an updated and more comprehensive model for ion and water transport with additional putative transporters for Na⁺ and Cl^- uptake in the anal papillae. These are organs which are actively engaged in Na⁺, Cl^- and water uptake and regulation when the aquatic larvae encounter fluctuating salinities over the course of their development. Furthermore the transcriptome of the anal papillae includes a full set of xenobiotic detoxification genes suggesting that these are important detoxification organs which is particularly important when larvae reside in polluted water.

Downregulation of thromboxane A2 and angiotensin II type 1 receptors associated with aging-related decrease in internal anal sphincter tone

Aging-associated decrease in internal anal sphincter (IAS) tone (AADI) is a major contributor in the rectoanal incontinence (RI). To determine the pathogenesis of AADI, we investigated the effect of aging on GPCR activation and related downstream signaling. We particularly investigated two GPCRs that characterize IAS smooth muscle cells (SMCs): thromboxane A2 and angiotensin II type 1. Two groups of Fischer 344 rats (6-month-old [young group] and 26-month-old [old group]) were employed to determine the GPCR function by isometric contraction, the expressions of GPCRs, and their downstream regulatory signaling proteins (regulator of G-protein signaling 2, RGS2; GPCR Kinase 5, GRK5; and β-arrestin, Arrb2) using RT-PCR, qPCR, and western blot analyses. We used reversible biotinylation to monitor the GPCR trafficking using SMCs. Aging selectively attenuated thromboxane A2 and Ang II-induced IAS contraction. RT-PCR, qPCR, and WB data revealed a significant decrease in the expressions of the GPCRs and increase in the expression of RGS2, GRK5, and Arrb2. The increased GPCR internalization and decreased recycling under aging were validated by reversible biotinylation. We conclude that downregulation of GPCR, accompanied by upregulation of regulatory proteins, plays an important role in receptor desensitization and may be important underlying mechanisms of RI in certain aging patients.

Isolation of internal and external sphincter progenitor cells from the human anal sphincter with or without radiotherapy

AIM

We aimed to isolate and propagate internal and external anal sphincter progenitor cells from the human anal sphincter, with or without radiotherapy, for tailored cell therapy of faecal incontinence.

METHODS

Sphincter progenitor cells were isolated from normal internal and external anal sphincters collected from 10 patients with rectal cancer who had undergone abdominoperineal resection with (n = 6) or without (n = 4) preoperative chemoradiotherapy. The isolated cells and differentiated muscle fibres were identified using immunofluorescence assay, western blotting and reverse transcription polymerase chain reaction (RT-PCR). The proliferation of progenitor cells with and without radiotherapy was compared by quantitative 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

RESULTS

The immunofluorescence assay before differentiation confirmed that the internal anal sphincter progenitor cells expressed CD34 and neural-glial antigen 2 (NG2), whereas the external anal sphincter progenitor cells expressed CD34 and PAX7. After differentiation, the internal anal sphincter progenitor cells expressed desmin, calponin and α-smooth muscle actin, whereas the external anal sphincter progenitor cells expressed desmin, myogenic factor 4 and myosin heavy chain. The differential expression profiles of both cell types were confirmed by western blotting and RT-PCR. MTT assays showed that the viability of internal and external anal sphincter progenitor cells was significantly lower in the radiotherapy group than that in the nonradiotherapy group.

CONCLUSIONS

This study describes the differential harvest internal and external sphincter muscle progenitor cells from human anal sphincters. We confirm that radiotherapy decreases the viability of internal and external anal sphincter progenitor cells.

Changes in murine anorectum signaling across the life course

BACKGROUND

Increasing age is associated with an increase in the incidence of chronic constipation and fecal impaction. The contribution of the natural aging process to these conditions is not fully understood. This study examined the effects of increasing age on the function of the murine anorectum.

METHODS

The effects of increasing age on cholinergic, nitrergic, and purinergic signaling pathways in the murine anorectum were examined using classical organ bath assays to examine tissue function and electrochemical sensing to determine age-related changes in nitric oxide and acetylcholine release.

KEY RESULTS

Nitrergic relaxation increased between 3 and 6 months, peaked at 12 months and declined in the 18 and 24 months groups. These changes were in part explained by an age-related decrease in nitric oxide (NO) release. Cholinergic signaling was maintained with age by an increase in acetylcholine (ACh) release and a compensatory decrease in cholinesterase activity. Age-related changes in purinergic relaxation were qualitatively similar to nitrergic relaxation although the relaxations were much smaller. Increasing age did not alter the response of the anorectum smooth muscle to exogenously applied ACh, ATP, sodium nitroprusside or KCl. Similarly, there was no change in basal tension developed by the anorectum.

CONCLUSIONS AND INFERENCES

The decrease in nitrergic signaling with increasing age may contribute to the age-related fecal impaction and constipation previously described in this model by partially obstructing defecation.

Characterization of cadmium and calcium fluxes along the gut, malpighian tubules, and anal papillae of the dipteran Chironomus riparius

Chironomids are often one of the dominant organisms in significantly polluted freshwater. Many invertebrate studies have characterized whole-organism mechanisms of toxicity, for example, assessing cadmium (Cd) uptake via calcium (Ca) channels. However, with the use of the scanning ion-selective electrode technique and an innovative Cd-selective microelectrode, we analyze this relationship at the organ level using a realistic concentration of Cd and Ca in the hemolymph (blood). Generally, Cd fluxes follow the same directional pattern as Ca, although Ca fluxes are approximately 5 times higher than those of Cd. These results correlate well with previous studies indicating that chironomids have a higher affinity for Ca over Cd, which affords them tolerance to Cd toxicity. When saline Ca concentration was increased to 10 times physiological levels, Cd fluxes from the gut lumen into the cells of the midgut regions were reduced by 50 to 80%. Transport of Cd from hemolymph to tissue for the posterior midgut, Malpighian tubule, and proximal ceca was also reduced by approximately 50%. The present results indicate that Cd fluxes into or across the gut and Malpighian tubules are reduced by high Ca, suggesting that Cd may be transported in some cells by similar mechanisms. However, Cd was actively excreted at the anal papillae after a 48-h waterborne exposure to Cd, but this process was independent of Ca and instead may involve a P-glycoprotein-related pump to detoxify Cd. Environ Toxicol Chem 2018;37:2542-2549. © 2018 SETAC.

Differential expression of putative sodium-dependent cation-chloride cotransporters in Aedes aegypti

The yellow fever mosquito, Aedes aegypti, has three genes that code for proteins with sequence similarity to vertebrate Na⁺-K⁺-Cl^- cotransporters (NKCCs) of the solute-linked carrier 12 superfamily of cation-chloride cotransporters (CCCs). We hypothesized that these mosquito NKCC orthologues have diverged to perform distinct roles in salt secretion and absorption. In phylogenetic analyses, one protein (aeNKCC1) groups with a Drosophila melanogaster NKCC that mediates salt secretion whereas two others (aeCCC2 and aeCCC3) group with a Drosophila transporter that is not functionally characterized. The aeCCC2 and aeCCC3 genes probably result from a tandem gene duplication in the mosquito lineage; they have similar exon structures and are consecutive in genomic DNA. Predicted aeCCC2 and aeCCC3 proteins differ from aeNKCC1 and vertebrate NKCCs in residues from the third transmembrane domain known to influence ion and inhibitor binding. Quantitative PCR revealed that aeNKCC1 and aeCCC2 were approximately equally expressed in larvae and adults, whereas aeCCC3 was approximately 100-fold more abundant in larvae than in adults. In larval tissues, aeCCC2 was approximately 2-fold more abundant in Malpighian tubules compared to anal papillae. In contrast, aeCCC3 was nearly 100-fold more abundant in larval anal papillae compared to Malpighian tubules, suggesting a role in absorption. Western blots with polyclonal antibodies against isoform-specific peptides revealed stronger aeCCC2 immunoreactivity in adults versus larvae, whereas aeCCC3 immunoreactivity was stronger in larvae versus adults. The differential expression pattern of aeCCC2 and aeCCC3, and their sequence divergence in transmembrane domains, suggests that they may have different roles in transepithelial salt transport.

Curative effect of Amorphophallus paeoniifolius tuber on experimental hemorrhoids in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Amorphophallus paeoniifolius (Dennst.) Nicolson (Family- Araceae) is a crop of south East Asian origin. In India, its tuber is widely used in ethnomedicinal practices by different tribes for the treatment of piles (hemorrhoids).

AIM

The present study evaluated the effect of methanolic and aqueous extract of Amorphophallus paeoniifolius tuber on croton oil induced hemorrhoids in rats.

MATERIALS AND METHODS

The methanolic extract was standardized with the major phenolic compound, betulinic acid, by HPLC. The hemorrhoids were induced by applying 6% croton oil preparation in the ano-rectal region. Rats were orally administered methanolic and aqueous extract at doses of 250 and 500mg/kg, each for 7 days. Pilex (200mg/kg) was used as reference anti-hemorrhoidal drug. Hemorrhoids were assessed on eighth day by measuring hemorrhoidal and biochemical parameters along with histology of ano-rectal tissue.

RESULTS

Croton oil application caused induction of hemorrhoids as indicated by significant (p<0.001) increase in plasma exudation of Evans blue in ano-rectal tissue, macroscopic severity score and ano-rectal coefficient as compared to normal rats. It significantly (p<0.001) elevated lactate dehydrogenase and cytokines (TNF-α and IL-6) levels in serum and increased myeloperoxidase activity and lipid peroxidation in ano-rectal tissue along with marked histological damage as compared to normal rats. Treatment with tuber extracts and pilex significantly (p<0.05-p<0.001) ameliorated Evans blue exudation, hemorrhoidal parameters and other biochemical parameters with attenuation of tissue damage compared to hemorrhoid control rats. The results indicate that tuber extracts exhibited curative action on hemorrhoids. The aqueous extract showed more pronounced effect than methanolic extract. The effects may be attributed to anti-inflammatory and antioxidant properties.

CONCLUSION

Results indicate that tuber of Amorphophallus paeoniifolius exhibited curative action on hemorrhoids through anti-inflammatory and antioxidant properties. The study validates the ethnomedicinal use of tuber in hemorrhoids and implicates its therapeutic potential as an anti-hemorrhoidal agent.

Tissue-Engineered External Anal Sphincter Using Autologous Myogenic Satellite Cells and Extracellular Matrix: Functional and Histological Studies

The aim of the present study was to demonstrate the regaining histological characteristics of bioengineered external anal sphincters (EAS) in rabbit fecal incontinence model. The EAS of 16 rabbits were resected and decellularized. The decellularized scaffolds were transplanted to the terminal rectum following a period of 6 months of fecal incontinency (5 days after sterilization). The rabbits were divided into two groups: in group 1 (n = 8), myogenic satellite cells were injected into the transplanted sphincters. In group 2 (n = 8), the transplanted scaffolds remained in situ without cellular injection. The histological evaluation was performed with desmin, myosin, smooth muscle actin, CD31, and CD34 at 3-month intervals. The rabbits were followed for 2 years. Electromyography (EMG) with needle and electrical stimulation, pudendal and muscle electrical stimulation were also performed after 2 years of transplantation. At the time of biopsy, no evidence of inflammation or rejection was observed and the transplanted EAS appeared histologically and anatomically normal. The immunohistochemistry staining validated that the histological features of EAS was more satisfactory in group 1 in short-term follow-up. However, no statistically significant difference was detected between two groups in long-term follow-ups (p value > 0.05). In both groups, grafted EAS contracted in response to electrical signals delivered to the muscle and the pudendal nerve. However, more signals were detected in group 1 in EMG evaluation. In conclusion, bioengineered EAS with myogenic satellite cells can gain more satisfactory histological outcomes in short-term follow-ups with better muscle electrical stimulation outcomes.

Clinicopathologic Features Associated With Human Papillomavirus/p16 in Patients With Metastatic Squamous Cell Carcinoma of the Anal Canal

BACKGROUND

The incidence of anal carcinoma in the U.S. continues to increase steadily, and infection with the human papillomavirus (HPV) is an established risk factor for the development of anal carcinoma. However, the clinicopathologic characteristics of patients with metastatic squamous cell carcinoma of the anal canal according to HPV status have not yet been defined.

MATERIALS AND METHODS

The records of patients treated for metastatic squamous cell carcinoma of the anal canal at the MD Anderson Cancer Center from June 2005 to August 2013 were reviewed. The patients were tested for the presence of HPV DNA by in situ hybridization and/or the p16 oncoprotein by immunohistochemistry. Associations between the presence of HPV and clinicopathologic attributes were measured.

RESULTS

Of the 72 patients reviewed, 68 tumors (94%) had detectable HPV. Patients with HPV-negative tumors were more likely to be of nonwhite ethnicity (odds ratio, 8.7) and have a strong (>30 pack-year) tobacco history (odds ratio, 8.7). A trend toward improved survival from the time of diagnosis of metastatic disease was noted among patients with HPV-positive tumors.

CONCLUSION

Most patients with metastatic anal cancer had detectable HPV, with differences in tobacco history and ethnicity detected according to HPV status. The high frequency of HPV positivity for patients with metastatic anal cancer has important implications for novel immunotherapy treatment approaches, including ongoing clinical trials with immune checkpoint blockade agents using antibodies targeting the programmed death-1 receptor.

IMPLICATIONS FOR PRACTICE

Previous studies investigating the clinical features of patients with anal cancer focused on those with early-stage disease. The present study characterizes, for the first time, clinical and pathological features according to human papillomavirus (HPV) status for patients with metastatic anal cancer. A high frequency of HPV-positive tumors and correlations between HPV status and both ethnicity and tobacco history was found. No standard-of-care therapy is available for patients with metastatic anal cancer, and most receive cytotoxic chemotherapy. The high prevalence of HPV in the current population generates optimism for ongoing clinical trials investigating the role of immune checkpoint blockade agents as a novel treatment approach for this disease.

Spatiotemporal expression of BMP7 in the development of anorectal malformations in fetal rats

The aim of this study was to determine the expression patterns of bone morphogenetic protein 7 (BMP7) during anorectal development in normal rat embryos and in embryos with anorectal malformations (ARM), and to investigate the possible role of BMP7 in the pathogenesis of ARM. ARM was induced by treating rat embryos with ethylenethiourea on the 10th gestational day (GD10). Embryos were harvested by Cesarean delivery and the spatiotemporal expression of BMP7 was evaluated in normal (n=168) and ARM embryos (n=171) from GD13 to GD16 using immunohistochemistry staining and western blot analysis. Immunohistochemical staining in normal embryos revealed that BMP7 was abundantly expressed on the epithelium of the urorectal septum (URS) and the hindgut on GD13, and BMP7-immunopositive cells were extensively detected in the URS, hindgut, and cloacal membrane by GD14. Increased positive tissue staining was noted on the fused tissue of the URS and the thin anal membrane on GD15. In ARM embryos, the epithelium of the cloaca, URS, and anorectum were negatively or only faintly immunostained for BMP7. BMP7 protein expression showed time-dependent changes in the developing hindgut according to western blotting, and reached a peak on GD15 during anus formation. BMP7 expression levels from GD14 to GD15 were significantly lower in the ARM group compared with the normal group (P<0.05). Spatiotemporal expression of BMP7 was disrupted in ARM embryos during anorectal morphogenesis from GD13 to GD16. These results suggest that downregulation of BMP7 at the time of cloacal separation into the primitive rectum and UGS might be related to the development of ARM.

Hypermethylation of SHH in the pathogenesis of congenital anorectal malformations

OBJECTIVE

This study sought to examine promoter methylation and expression of the identified sonic hedgehog (SHH) gene in terminal rectal tissues of children with congenital anorectal malformations (ARMs).

METHODS

Tissue samples from the terminal rectum of pediatric patients with ARMs (five cases each of high and intermediate malformation - two cases of rectovesical fistula, two cases of rectourethral prostatic fistula, one case of cloaca with >3cm common channel, four cases of rectourethral bulbar fistula and one case of imperforate anus without fistula, respectively, and ten cases of low malformation - five cases of perineal fistula and five cases of vestibular fistula, respectively), and patients with non-gastrointestinal tract malformation (six cases, anal fistula) were collected and divided into three groups: high-intermediate ARM (ARMhi-int), low ARM (ARMlo), and control (Cont.). Real-time RT-PCR was used to detect mRNA expression levels of the verified differentially methylated gene SHH, and bisulfite genomic sequencing was performed to evaluate DNA methylation in the SHH promoter region.

RESULTS

The average methylation levels of the SHH promoter were significantly higher in ARMhi-int (0.850±0.030, P=0.0036) and ARMlo (0.540±0.053, P=0.0087) groups than in Cont. group (0.280±0.032). SHH mRNA expression levels were lower in ARMhi-int (0.340±0.015, P=0.0065) and ARMlo (0.530±0.042, P=0.0156) groups than in Cont. group (0.870±0.046). The average methylation levels of the SHH promoter were higher in ARMhi-int group than in ARMlo group (0.850±0.030 vs. 0.540±0.053, P=0.0095), while SHH expression was significantly reduced in ARMhi-int group compared to ARMlo group (0.340±0.15 vs. 0.530±0.042, P=0.0252). The methylation levels of the SHH promoter in ARMhi-int group were negatively correlated with SHH gene expression (r=-0.89, P<0.01).

CONCLUSIONS

The SHH gene, which plays a major role in the development of the anorectum and enteric nervous system, is hypermethylated at its promoter, and this is correlated with low levels of SHH gene expression. This epigenetic modification may therefore be responsible for the observed changes in SHH expression, which could in turn underlie the pathogenesis of congenital ARMs.

Functional outcome after anal sphincter injury and treatment with mesenchymal stem cells

This research demonstrates the regenerative effects of mesenchymal stem cells (MSCs) on the injured anal sphincter by comparing anal sphincter pressures following intramuscular and serial intravascular MSC infusion in a rat model of anal sphincter injury. Fifty rats were divided into injury (n = 35) and no injury (NI; n = 15) groups. Each group was further divided into i.m., serial i.v., or no-treatment (n = 5) groups and followed for 5 weeks. The injury consisted of an excision of 25% of the anal sphincter complex. Twenty-four hours after injury, 5 × 10(5) green fluorescent protein-labeled MSCs in 0.2 ml of phosphate-buffered saline (PBS) or PBS alone (sham) were injected into the anal sphincter for i.m. treatment; i.v. and sham i.v. treatments were delivered daily for 6 consecutive days via the tail vein. Anal pressures were recorded before injury and 10 days and 5 weeks after treatment. Ten days after i.m. MSC treatment, resting and peak pressures were significantly increased compared with those in sham i.m. treatment (p < .001). When compared with the NI group, the injury groups had anal pressures that were not significantly different 5 weeks after i.m./i.v. treatment. Both resting and peak pressures were also significantly increased after i.m./i.v. MSC treatment compared with treatment with PBS (p < .001), suggesting recovery. Statistical analysis was done using paired t test with Bonferroni correction. Marked decrease in fibrosis and scar tissue was seen in both MSC-treated groups. Both i.m. and i.v. MSC treatment after injury caused an increase in anal pressures sustained at 5 weeks, although fewer cells were injected i.m. The MSC-treated groups showed less scarring than the PBS-treated groups, with the i.v. infusion group showing the least scarring.

Novel histopathological and molecular effects of natural compound pellitorine on larval midgut epithelium and anal gills of Aedes aegypti

The yellow fever mosquito, Aedes aegypti, is a vector for transmitting dengue fever and yellow fever. In this study, we assessed the histopathological and molecular effects of pellitorine, an isobutylamide alkaloid, on the third instar of Ae. aegypti larvae. At 5 mg/l concentration of pellitorine, the whole body of the treated larvae became dark in color, particularly damaged thorax and abdominal regions. Pellitorine was targeted mainly on midgut epithelium and anal gills, indicating variably dramatic degenerative responses of the midgut through a sequential epithelial disorganization. The anterior and posterior midgut was entirely necrosed, bearing only gut lumen residues inside the peritrophic membranes. Pellitorine caused comprehensive damage of anal gill cells and branches of tracheole and debris was found in hemolymph of the anal gills. RT-PCR analysis indicates that the compound inhibited gene expression encoding V-type H⁺-ATPase and aquaporine 4 after treatment with 2.21 mg/l pellitorine. These results verify that pellitorine merits further study as a potential larvicide with a specific target site and a lead molecule for the control of mosquito populations.

Chemical compounds from the preanal gland secretions of the male tree agama (Acanthocercus atricollis) (fam. Agamidae)

Chemical signals have an important role in the reproductive behaviour of many lizards. However, the compounds secreted by their femoral or preanal glands, which may be used as sexual signals, are mainly known for lizard species within the Scleroglossa clade, whereas compounds in secretions of lizards within the Iguania clade are much less studied. Based on mass spectra, obtained by GC-MS, we found 60 lipophilic compounds in preanal gland secretions of the male tree agama (Acanthocercus atricollis) (fam. Agamidae), including steroids (mainly cholesterol, cholest-3-ene, and some of their derivatives), fatty acids ranging between n-C12 and n-C18 (mainly hexadecanoic and octadecenoic acids), ketones from n-C17 to n-C25, and other minor compounds, such as tocopherol, squalene, waxy esters, and furanones. We compare the compounds found with those present in other lizard species and discuss their potential function in social behaviour.

α-Tocopherol supplementation avoids apoptosis in the anal sphincter

PURPOSE

To analyze the influence of α-tocopherol supplementation on the levels of oxidative stress and apoptosis rates in the anal sphincter induced by orchiectomy in rats.

METHODS

Forty male Wistar rats weighing 250-300 g, were divided into four groups and sacrificed 8 weeks after: I- Control: sham; II- Orchiectomy: bilateral orchiectomy; III- Pre Orchiectomy Tocopherol: α-tocopherol supplementation for 4 weeks preceding bilateral orchiectomy; IV- Orchiectomy Full Tocopherol: α-tocopherol supplementation for 4 weeks before and 8 weeks after bilateral orchiectomy. The anal sphincter was analyzed stereologically to evaluate the density of collagen and the muscle fibers. The oxidative stress and the apoptosis were determined with 8-isprostane and caspase-3, respectively.

RESULTS

The collagen fibers concentration was statistically greater in Orchiectomy group than the others. The muscle fibers concentration was higher in Control and Orchiectomy Full Tocopherol than Orchiectomy and Pre Orchiectomy Tocopherol groups. Orchiectomy group showed higher 8-isoprostane concentrations compared to the other groups (p < 0.0003). Pre Orchiectomy Tocopherol and Orchiectomy Full Tocopherol groups presented caspase-3 levels lower than the Orchiectomy group (0.0072).

CONCLUSION

Vitamin supplementation with α-tocopherol for 12 weeks had the highest protection against bilateral orchiectomy generation of reactive oxygen species as well as apoptosis in the muscle fibers of the anal sphincter of rats.

Pharmacokinetics of anorectal nifedipine and lidocaine (lignocaine) ointment following haemorrhoidectomy: an open-label, single-dose, phase IV clinical study

OBJECTIVES

This study aimed to assess whether topical anorectal application of an ointment containing nifedipine (0.3% w/w) and lidocaine (lignocaine) [1.5% w/w] to patients undergoing Milligan-Morgan haemorrhoidectomy achieves pharmacologically relevant serum concentrations of the active ingredients and has any haemodynamic effects or adverse effects.

METHODS

A single dose of 3 g of study ointment was circumferentially applied inside the anus to 24 patients (17 males and 7 females) aged 23-71 years (mean +/- SD: 42.9 +/- 4.9 years) during postoperative dressing after Milligan-Morgan haemorrhoidectomy from March 2007 to January 2008. Blood samples for the determination of nifedipine and lidocaine serum concentrations were drawn before surgery and at 20, 40, 60, 90, 120, 240, 360, 480 and 720 minutes after application. Serum concentrations of nifedipine and lidocaine were determined by a high-performance liquid chromatography method in order to calculate pharmacokinetic parameters. Patients' BP, heart rate and ECG readings were monitored during the study.

RESULTS

Chromatographic signals of nifedipine were sporadically observed in only five patients (20.8%), consistent with therapeutically negligible concentrations and insufficient to permit calculation of any pharmacokinetic parameters. The serum concentrations of nifedipine in these five patients ranged from 5.9 to 18.8 ng/mL. Lidocaine concentrations were detectable in all patients. The means +/- SD and medians of pharmacokinetic parameters for lidocaine were as follows: maximum serum concentration (C(max)) 245.1 +/- 370.8 ng/mL, 73.6 ng/mL; time to reach C(max) (t(max)) 69.2 +/- 78.3 minutes, 40 minutes; area under the serum concentration-time curve from 0 to 6 hours (AUC(6)) 756.5 +/- 1254.1 ng.h/mL, 238.2 ng.h/mL. Only three patients had maximum serum concentrations above 1000 ng/mL (1037.8, 1044.75 and 1364.1 ng/mL). These outlier concentrations were four to five times lower than the threshold of CNS lidocaine toxicity (5000-6000 ng/mL). No serious local or systemic adverse events were observed throughout the study, and no subjects developed arrhythmias or significant ECG changes. Neither BP nor mean heart rate varied significantly after application of a single dose.

CONCLUSIONS

This study demonstrates that single-dose topical application of an ointment containing nifedipine (0.3% w/w) and lidocaine (1.5% w/w) to patients undergoing Milligan-Morgan haemorrhoidectomy is safe to use. Following application onto damaged anorectal mucosa, nifedipine and lidocaine are absorbed into the bloodstream in small quantities that do not have any major implications for the safety of the product. Further studies are required to evaluate nifedipine and lidocaine concentrations in serum using a multiple-dose regimen.

Characterization of the alpha1-adrenoceptor subtype mediating contractions of the pig internal anal sphincter

BACKGROUND AND PURPOSE

The internal anal sphincter has been shown to contract in response to alpha1-adrenoceptor stimulation and therefore alpha1-adrenoceptor agonists may be useful in treating faecal incontinence. This study characterizes the alpha1-adrenoceptor subtype responsible for mediating contraction of the internal anal sphincter of the pig.

EXPERIMENTAL APPROACH

The potency of agonists and the affinities of several receptor subtype selective antagonists were determined on smooth muscle strips for the pig internal anal sphincter. Cumulative concentration-response curves were performed using phenylephrine and noradrenaline.

KEY RESULTS

The potency of the alpha1A-adrenoceptor selective agonist A61603 (pEC50=7.79+/-0.04) was 158-fold greater than that for noradrenaline (pEC50=5.59+/-0.02). Phenylephrine (pEC50=5.99+/-0.05) was 2.5-fold more potent than noradrenaline. The alpha1D-adrenoceptor selective antagonist BMY7378 caused rightward shifts of the concentration-response curves to phenylephrine and noradrenaline, yielding low affinity estimates of 6.59+/-0.15 and 6.33+/-0.13, respectively. Relatively high affinity estimates were obtained for the alpha1A-adrenoceptor selective antagonists, RS100329 (9.01+/-0.14 and 9.06+/-0.22 with phenylephrine and noradrenaline, respectively) and 5-methylurapidil (8.51+/-0.10 and 8.31+/-0.10, respectively). Prazosin antagonized responses of the sphincter to phenylephrine and noradrenaline, yielding mean affinity estimates of 8.58+/-0.10 and 8.15+/-0.08, respectively. The Schild slope for prazosin with phenylephrine was equal to unity (1.01+/-0.24), however the Schild slope using noradrenaline was significantly less than unity (0.50+/-0.11, P<0.05).

CONCLUSION AND IMPLICATIONS

The results suggest that contraction of circular smooth muscle from the pig internal anal sphincter is mediated via a population of adrenoceptors with the pharmacological characteristics of the alpha1A/L-adrenoceptor, most probably the alpha1L-adrenoceptor form of this receptor.

Epithelial and muscular regionalization of the human developing anorectum

In the past, interpretations of anorectal development were mainly based on analysis of serially sectioned embryos of various nonhuman species as well as some human specimens. A four-dimensional view of the developmental situation in the human has never been established nor connected to recent findings obtained from newer molecular techniques. We, therefore, investigated human embryonic and fetal pelves by means of immunohistochemistry and in situ hybridization to elucidate differentiation and interaction of epithelial and mesenchymal layers of the anorectum. To emphasize spatial as well as sequential morphological development, we produced three-dimensional reconstructions of the specimens at hand. Research conducted proved that the decisive steps of epithelial and muscular differentiation occur between the 7th and 9th week after conception. This study elucidates a biphasic epithelial "closure" in the anal canal and interactions between epithelium, smooth musculature, and skeletal musculature. Based on the results presented here, it is possible to describe the pathogenesis of two anorectal malformations: the imperforate anal membrane and the anal membrane stenosis. This study will now provide the basis for further research into developmental processes occurring before the ones examined.

Combined estrogen and ghrelin administration restores number of blood vessels and collagen type I/III ratio in the urethral and anal canal submucosa of old ovariectomized rats

We compare the effects of estrogen and/or ghrelin on vascular counts and collagen I/III ratio of urethral and anal canal submucosa in old vs young-adult ovariectomized rats. Ovariectomized Fisher 344 rats (18 and 3 months old, n = 24 x 2) received 42 daily intraperitoneal 17-ss estradiol (10 microg/kg), ghrelin (2 microg/kg), both, or vehicle (n = 6 x 4 per group). Blood vessel counts and collagen I/III ratio were measured, respectively, by light microscopy and Western blot analysis with immunohistochemistry of ghrelin receptors. Estrogen significantly increased urethral and anal vascular counts and collagen I/III ratio in young-adult rats. In old rats, only combined estrogen/ghrelin administration significantly increased both variables. This was not observed with estrogen or ghrelin separately. Ghrelin receptors were immunostained in urethral and anal submucosa of all samples. Combined estrogen/ghrelin administration restored postovariectomy urethral and anal canal submucosal vessel number and collagen I/III ratio in old rats suggesting independent ageing effect.

Immunophenotypic Characterization of Anal Gland Carcinoma: Loss of p63 and Cytokeratin 5/6

Anal gland carcinoma (AGC) is a rare perianal invasive cancer composed of tubular glands lined by cuboidal epithelium. The clinical features and histogenesis of AGC are not well understood and its origin from anal glands is often difficult to prove. Little is known about immunophenotypic features of AGC that could be useful in establishing the diagnosis. This study evaluated the immunohistochemical profile of 2 cases of AGC in comparison to anal glands from 11 hemorrhoidectomy specimens. Sections from the specimens were routinely processed and immunostained using commercial antibodies to cytokeratin (CK) 7, CK20, CK5/ 6, p63, CDX2, smooth muscle actin, calponin, heavy chain smooth muscle myosin, p53, and p16. In case 1 of AGC, radiation and chemotherapy preceded an abdominoperineal resection. In biopsies from this case, the neoplastic anal glands had a tubular pattern, whereas most glands in the resection specimen exhibited mucinous features. The histologic pattern in case 2 was tubular. Normal anal glands showed immunoreactivity for myoepithelial and basal cell markers CK5/6 and p63 in basal and parabasal cell layers and for CK7 in superficial cell layers. In contrast, both cases of AGC were negative for CK5/6 and p63 and were diffusely positive for CK7. Normal glands and both cases of AGC were negative for the intestinal differentiation marker CDX2, CK20, smooth muscle actin, calponin, smooth muscle myosin heavy chain, p16, and p53. Our data suggest that loss of p63 and CK5/6 expression is a feature of AGC. Anal gland carcinoma shares negativity for CDX2 and CK7+/CK20− profile with normal anal glands. No evidence of myoepithelial cells was found in normal or malignant anal glands. These data may be useful in establishing the diagnosis of AGC.

Gastrointestinal stromal tumor arising from anorectum: correlation of imprint cytology and radiologic imaging

The diagnosis of gastrointestinal stromal tumor (GIST) is generally established on histopathologic examination of surgical specimens. Gastrointestinal stromal tumor comprises a heterogenous group of neoplasms of the gastrointestinal tract previously referred to as leiomyomas, leiomyosarcomas, or schwannomas. Gastrointestinal stromal tumor arising from anorectum is a rare instance. We report a case of GIST for the correlation of imaging and cytologic features with immunocytochemical staining. A computed tomography and magnetic resonance imaging confirmed a 2-cm tumor growing into the rectal lumen. The central portion of the tumor showed T1-weighted imaging of low signal and suspected central necrosis by the T2-weighted imaging of high signal. Imprint cytology from excised tumors showed isolated or loosely aggregated spindle cells with scanty and fibrillary cytoplasmic processes, nuclear pleomorphism, fine granular chromatin, and irregular nuclear margins. Epithelioid tumor cells showed grooves with abundant cytoplasm and several round nucleoli. Both c-kit and CD34 antigen were positive with strong and diffuse stainability in smears as well as paraffin sections by immunoperoxidase staining. We suggest that the combined use of imaging diagnosis and cytology with immunocytochemical staining are useful initial diagnosis of GIST.

Cellular regulation of basal tone in internal anal sphincter smooth muscle by RhoA/ROCK

Sustained contractions of smooth muscle cells (SMC) maintain basal tone in the internal anal sphincter (IAS). To examine the molecular bases for the myogenic tone in the IAS, the present studies focused on the role of RhoA/ROCK in the SMC isolated from the IAS vs. the adjoining phasic tissues of the rectal smooth muscle (RSM) and anococcygeus smooth muscle (ASM) of rat. We also compared cellular distribution of RhoA/ROCK, levels of RhoA-GTP, RhoA-Rho guanine nucleotide dissociation inhibitor (GDI) complex formation, levels of p(Thr696)-MYPT1, and SMC relaxation caused by RhoA inhibition. Levels of RhoA/ROCK were higher at the cell membrane in the IAS SMC compared with those from the RSM and ASM. C3 exoenzyme (RhoA inhibitor) and Y 27632 (ROCK inhibitor) caused a concentration-dependent relaxation of the IAS SMC. In addition, active ROCK-II (primary isoform of ROCK in SMC) caused further shortening in the IAS SMC. C3 exoenzyme increased RhoA-RhoGDI binding and reduced the levels of RhoA-GTP and p(Thr696)-MYPT1. ROCK inhibitor attenuated PKC-induced contractions in IAS SMC. Conversely, a PKC inhibitor (Gö 6850, which causes partial relaxation of the SMC) had no significant effect on ROCK-II-induced contractions. Further experiments showed the highest levels of RhoA, active form of RhoA (RhoA-GTP), ROCK-II, 20-kDa myosin regulatory light chain (MLC(20)), phospho-MYPT1, and phospho-MLC(20) in the IAS vs. RSM and ASM SMC. However, the trend was the reverse with the levels of inactive RhoA (GDP-RhoA-RhoGDI complex) and MYPT1. We conclude that RhoA/ROCK play a critical role in maintenance of spontaneous tone in the IAS SMC via inhibition of myosin light chain phosphatase.

Expression of estrogen receptor-alpha protein in the rat digestive tract

The current study evaluates the expression of estrogen receptor-alpha (ER-alpha) protein in the digestive tract and other organs using immunohistochemistry in male and female intact rats. As a result, the expression of ER-alpha protein was intensively immunoreactive in the nuclei of squamous epithelium of the forestomach connected to the limiting ridge and the anus connected to the anorectal junction. Rat ER-alpha mRNA signals were also detected in the epithelium of the limiting ridge using in situ hybridization. The incidence of ER-alpha protein in the limiting ridge decreased with age in both males and females. The incidence of ER-alpha protein in the anorectal junction strongly decreased with age in males, although the incidence did not decrease with age in females. In conclusion, it was suggested that estrogen may be involved in the proliferation and differentiation of these cells in the limiting ridge of the stomach and anorectal junction of rats.

Diabetes mellitus and anal sphincter pressures: an experimental model in rats

PURPOSE

Symptoms of the gastrointestinal tract, frequent in patients with diabetes mellitus, which may be related to an increase in the production of free radicals, include alterations in the function of the sphincter anal musculature. Such alterations are characterized by a decrease of muscular tone associated with different degrees of fecal incontinence. This study was performed to show the alterations in the anal sphincter pressures of diabetic rats and to evaluate the role of nitric oxide and oxidative stress in this situation.

METHODS

Male Wistar rats weighing 250 to 400 g were used. The animals were divided in two groups: control and diabetic. Diabetes was induced through intraperitoneal injection of streptozotocin and the anal pressures were gauged by anorectal manometry. Nitric oxide was evaluated through measures of nitrites and nitrates, and oxidative stress through the technique of chemoluminescence.

RESULTS

There was a significant decrease in the sphincter anal pressure of diabetic animals 60 days after induction (P < 0.05). This pressure returned to basal values after administration of a nitric oxide synthase antagonist. The levels of nitrites and nitrates as well as of lipoperoxidation were significantly increased in the diabetic compared with the control group (P < 0.05).

CONCLUSIONS

In this study, hyperglycemia of diabetes mellitus caused an increase in the oxidative stress. Apparently the elevation of nitric oxide levels was one of the responsible factors for the decrease of anal sphincter pressures.

Anal canal adenocarcinoma with MUC5AC expression suggestive of anal gland origin

Anal canal adenocarcinomas arising in the anal ducts or glands are very rare neoplasms, and few useful immunohistochemical markers of these carcinomas are known to date. A 57-year-old man presented with anal bleeding, difficulty of defecation, and anal pain. Macroscopic findings of the surgically resected material showed circular stenosis of the anal canal. The mucosal surface was generally intact, but focal ulceration was seen. Microscopically, the proliferation of adenocarcinoma cells with mucin production was observed in the submucosal and muscular layers. The special stains of periodic acid-Schiff (PAS) and Alcian blue confirmed the presence of neutral and acid mucin. Immunohistochemically, normal rectal-type mucosa and normal anal ducts/glands showed the patterns of cytokeratin 7 (CK7)(-)/CK19(+, focal)/MUC5AC(-) and CK7(+, diffuse)/CK19(+, diffuse)/MUC5AC(+, focal), respectively, and neoplastic cells showed the pattern of CK7(+, diffuse)/CK19(+, diffuse)/MUC5AC(+, focal). Finally, our preliminary report suggests that the immunohistochemical combination of CK7, CK19, and MUC5AC may be an available marker for adenocarcinoma of anal ducts/glands origin.

Immunohistochemical staining for p63 is useful in the diagnosis of anal squamous cell carcinomas

Anal canal carcinomas account for between 1% and 2% of all gastrointestinal carcinomas in the United States. By far, the most common carcinoma in this site is squamous cell carcinoma, but the differential diagnosis typically includes poorly differentiated adenocarcinoma and well-differentiated neuroendocrine carcinoma or carcinoid tumor. Because the first diagnostic specimen received in the pathology laboratory is usually a small, sometimes suboptimal biopsy, the distinction of these types of carcinoma can be difficult. However, accurate diagnosis is imperative, because the treatment differs between squamous carcinoma (chemoradiation) and the other types of carcinoma (surgical therapy). The p63 protein has been previously shown to be involved in epithelial proliferation and differentiation, and is known to be related to squamous carcinomas in many sites. Therefore, we undertook to ascertain its usefulness in the diagnosis of squamous carcinomas in the anal canal. We retrieved 24 anal squamous carcinomas, 68 colorectal adenocarcinomas (including a tissue microarray), and 32 colorectal neuroendocrine carcinomas from the archives at the University of Michigan, and immunostained them for the p63 antigen. As a result, this immunohistochemical stain had a specificity of 98% and a positive predictive value of 92% for squamous cell carcinoma once invasive carcinoma had been established. It also stained the dysplastic epithelial cells in adjacent areas of anal intraepithelial neoplasia. We report that the p63 immunostain is a highly specific and useful tool in the diagnosis of carcinomas of the anal canal.

A male sexually dimorphic trait provides antimicrobials to eggs in blenny fish

Predation and microbial infections are the major causes of natural mortality for early life stages of oviparous species. The parental traits reducing the effects of predation are rather well described, whereas antimicrobial mechanisms enhancing offspring survival are largely unexplored. In this paper, we report that a male sexually dimorphic trait, the anal glands, of the redlip blenny (Ophioblennius atlanticus atlanticus) and the peacock blenny (Salaria pavo), two fish species with paternal egg care, produce a mucus enriched with antimicrobial substances. Histological and histochemical analyses showed that the anal glands of these species are characterized by the massive presence of mucus-secreting cells. Anal gland extracts, from both the hydrophilic and the hydrophobic protein fraction, exhibited a lysozyme-like activity. Field observations demonstrated that redlip blenny males, while performing egg care, rub the anal region over the nest internal surface, probably facilitating the transfer of mucus to eggs. These results strongly indicate that this sexually dimorphic trait is involved in egg defence against microbial infections.

Translocation of AT1- and AT2-Receptors by Higher Concentrations of Angiotensin II in the Smooth Muscle Cells of Rat Internal Anal Sphincter

Previous studies have reported bimodal effects by angiotensin II (Ang II) in the rat internal anal sphincter (IAS), a concentration-dependent contraction (at lower concentrations) and relaxation (at higher concentrations). The experiments suggest the above-mentioned responses are the result of Ang II subtype I receptor(s) (AT(1)-R) and subtype II receptor(s) (AT(2)-R) activation, respectively. These studies determined the role and mechanism of AT(2)-R-induced relaxation of the smooth muscle cells (SMCs) from the IAS in response to Ang II. Laser confocal microscopy showed that in the basal state, the AT(1)-Rs reside in the plasma membrane, whereas AT(2)-Rs are present in the cytosol. Higher concentrations of Ang II caused movement of AT(1)-R and AT(2)-R in opposite directions to the cytosol and the membrane, respectively. Losartan (AT(1)-R antagonist) but not S-(+)-1-([4-(dimethylamino)-3-methylphenyl]methyl)-5-(diphenylacetyl)-4,5,6,7-tetrahydro-1H-imidazo(4,5-c)pyridine-6-carboxylic acid (PD123319; AT(2)-R antagonist) selectively inhibited these movements. These results are based on biotinylation assays, confocal images, and Western blot analyses of the densities of AT(1)-Rs and AT(2)-Rs in the plasma membrane versus cytosolic fractions of the IAS SMCs. Ang II in higher concentrations did not change the total contents of Ang II receptors. These data combined with the functional data using measurements of IAS SMC lengths suggest that internalization of AT(1)-R and externalization of AT(2)-R may be responsible for the activation of the AT(2)-R, which leads to the relaxation of the IAS with higher concentrations of Ang II.

Estrogen and ghrelin decrease cytoplasmic expression of p27kip1, a cellular marker of ageing, in the striated anal sphincter and levator muscle of ovariectomized rats

A study was carried out to investigate the effect of estrogen and/or ghrelin on the cellular marker of ageing, p27kip1, in pelvic floor muscles of ovariectomized rats. Virgin Wistar rats (13 months old) underwent ovariectomy followed (1 month) by 42 daily intraperitoneal 17-beta estradiol (10 microg/kg), ghrelin (2 microg/kg), both hormones, or placebo vehicle (n=6x4 groups). Six more age-matched animals underwent sham surgery without ovariectomy. Cytoplasmic expression of p27kip1 in the striated urethral and anal sphincters and levator muscle was measured by Western blot analysis in all animals (n=30). p27kip1 signal intensity significantly increased postovariectomy in all muscles compared to sham animals. In the anal sphincter and levator, signal intensity decreased to sham levels with ghrelin or estrogen and decreased further after estrogen or ghrelin and estrogen/ghrelin administration. Urethral sphincter signal intensity decreased without reaching sham levels after drug administration. Estrogen and/or ghrelin replacement reverses the ovariectomy-induced exacerbation of biochemical cellular ageing in the anal sphincter and levator muscle of middle-aged rats.

Serum Levels and Possible Haemodynamic Effects following Anorectal Application of an Ointment Containing Nifedipine and Lignocaine

OBJECTIVES

This study aimed to assess whether topical anorectal application of an ointment containing nifedipine (0.3% w/w) and lignocaine (lidocaine) [1.5% w/w] to healthy adult volunteers gives rise to pharmacologically relevant serum levels of the active ingredients and has any haemodynamic effects or side effects.

METHODS

A dose of 3g of the ointment was circumferentially applied inside the anus to 12 healthy volunteers every 12 hours for 7 days. Blood samples were collected at 0, 30, 60, 240, 480 and 720 minutes after the first application; in addition, blood samples were collected at days 1 and 7 after multiple applications. Serum concentrations of nifedipine, its main metabolites and lignocaine were determined by a new high-performance liquid chromatography method established for the purpose of the study. Volunteers' blood pressure, heart rate, ECG status and laboratory parameters were monitored throughout the study.

RESULTS

Topical application of the ointment to healthy volunteers did not produce therapeutically significant serum levels of the active ingredients and/or their active metabolites. Indeed, chromatographic signals of the active ingredients and/or nifedipine metabolites were only sporadically observed, below the quantification limits for the method, and consistent with therapeutically negligible concentrations. No serious local or systemic adverse events were observed throughout the study, and no subjects developed arrhythmias or significant ECG changes. Neither blood pressure nor mean heart rate varied significantly after application of a single dose. After multiple doses, mean systolic and diastolic blood pressure remained close to baseline levels for the duration of the study. The mean heart rate after multiple doses was about 5% below baseline level at days 1 and 7; however, these differences were not statistically significant.

CONCLUSION

This study demonstrates the safety of topical anorectal application of an ointment containing nifedipine (0.3% w/w) and lignocaine (1.5% w/w) to healthy volunteers.

Basaloid Squamous Carcinoma of the Anal Canal With an Adenoid Cystic Pattern

Two cases of a distinctive variety of basaloid squamous carcinoma (BSC) of the anal canal are described. Both occurred in female patients who presented with bleeding per rectum. Histologic evaluation of the tumors showed lobules and aggregates of medium-sized basaloid cells with distinctive peripheral palisading and focal areas of central, comedo-necrosis. Accompanying dysplasia of the overlying squamous mucosa was absent. However, the microscopic pattern was dominated by the presence of eosinophilic, hyaline, paucicellular basement membrane-like material around and within tumor nests. This appearance together with microcystic spaces simulated that of an adenoid cystic carcinoma. Immunohistochemistry of the tumors revealed the following profile: CK7, CK5/CK6, 34betaE12 positive, CK14 focally positive but CK20 negative. The following were all negative: EMA, CEA, smooth muscle and muscle-specific actin, calponin, and S-100. The tumor cells exhibited diffuse nuclear positivity with p63. The eosinophilic basement membrane hyaline material was positive for collagen type IV and also for laminin. BSC of the anal canal with an adenoid cystic pattern is an infrequently encountered and reported variant, although it is seen more often in the aerodigestive tract. There may be an increased propensity for BSC with an adenoid cystic pattern to metastasize to the liver, but the number of cases encountered are too small to be definitive. The histologic differential diagnosis is true salivary gland-type adenoid cystic carcinoma and basal cell adenocarcinoma. Immunohistochemistry and awareness of this unusual pattern of BSC will facilitate the correct diagnosis being reached.

Nitric oxide not carbon monoxide mediates nonadrenergic noncholinergic relaxation in the murine internal anal sphincter

BACKGROUND & AIMS

Inhibitory reflexes in the internal anal sphincter (IAS) are controlled by inhibitory nonadrenergic, noncholinergic innervation (i-NANC). We investigated the roles of 3 different neurohumoral agonists as possible i-NANC neurotransmitters: carbon monoxide (CO), nitric oxide (NO), and vasoactive intestinal peptide (VIP).

METHODS

IAS smooth muscle strips were isolated from wild-type (WT), heme oxygenase (HO)-2 knockout (HO-2-/-) and neuronal NO synthase (nNOS) knockout (nNOS-/-) mice. Relaxation of IAS was induced by CO, NO, VIP, and electrical field stimulation (EFS) in the presence and absence of neurohumoral inhibitors (tin protoporphyrin IX [SnPP IX] for CO synthesis, N(omega)-nitro-L-arginine [L-NNA] for NO synthesis, and VIP(10-28) for VIP receptor). Western blot and immunohistochemistry were used to test the presence and localization of HO (for CO synthesis) types 1 (HO-1) and 2 (HO-2), neuronal NO synthase (nNOS, for NO synthesis), and VIP.

RESULTS

All 3 neurohumoral agonists produced relaxation (with no difference between WT and HO-2-/- IAS), but CO was over 100 times less potent than NO and VIP. EFS produced relaxation in WT and HO-2-/- IAS with the same intensity. L-NNA and nNOS deletion (approximately 80%) and VIP(10-28) (approximately 15%) significantly inhibited the relaxations, whereas SnPP IX had no effect. Positive immunoreactivities for HO-2, nNOS, and VIP were found in the myenteric plexus of WT IAS. HO-2-/- IAS did not express immunoreactivity for HO-2.

CONCLUSIONS

i-NANC relaxations of mouse IAS are primarily mediated via NO (by nNOS activity) and partly via VIP. CO directly relaxes the mouse IAS but does not play any significant role in the i-NANC relaxation.

DNA methylation in anal intraepithelial lesions and anal squamous cell carcinoma

PURPOSE

Anal intraepithelial neoplasia is associated with human papillomavirus infection and may progress to invasive squamous cell carcinoma (SCC), which is increasing in immunocompromised patients. We hypothesize that anal intraepithelial neoplasia is associated with abnormal DNA methylation and that detection of these events may be used to improve screening programs.

EXPERIMENTAL DESIGN

Seventy-six patients were identified who underwent anal cytology screening and subsequent biopsy at our institution between 1999 and 2004. The specimens from these patients included 184 anal biopsies [normal, n = 57; low-grade squamous intraepithelial lesion (LSIL), n = 74; high-grade squamous intraepithelial lesion (HSIL), n = 41; and invasive SCC, n = 12] and 37 residual liquid-based anal cytology specimens (normal, n = 11; LSIL, n = 12; HSIL, n = 14). The methylation status of the following genes was determined for each biopsy and cytology sample using real-time methylation-specific PCR: HIC1, RASSF1, RARB, CDKN2A, p14, TP73, APC, MLH1, MGMT, DAPK1, and IGSF4.

RESULTS

Methylation-specific PCR analysis of biopsy samples revealed that DNA methylation was more common in SCC and HSIL than LSIL and normal mucosa. Specifically, methylation of IGSF4 and DAPK1 was prevalent in SCC (75% and 75% of cases, respectively) and HSIL (59% and 71%, respectively) but was absent in LSIL and normal biopsy samples. Methylation profiles of cytologic samples were similar to those found in the biopsy samples.

CONCLUSIONS

Aberrant DNA methylation is a frequent event in anal HSIL and SCC. Methylation of IGSF4 and DAPK1 is specific for HSIL and SCC, and may serve as a useful molecular biomarker.

Putative Chemosignals of the Ferret (Mustela furo) Associated with Individual and Gender Recognition

Quantitative stir bar sorptive extraction methods, both in the aqueous and headspace modes, followed by thermal desorption gas chromatography-mass spectrometry were used to investigate individual variations in the volatile components of male and female ferret (Mustela furo) urine. The urinary profiles were further compared with volatile profiles of anal gland secretions of breeding male and female ferrets. Thirty volatile compounds were quantified in male and female urine. Among them, 2-methylquinoline was unique to male urine. Four ketones (4-heptanone, 2-heptanone, o-aminoacetophenone, and a dimethoxyacetophenone) and several nitrogen compounds (e.g., 2,5-dimethylpyrazine, quinoline, 4-methylquinazoline) and low levels of three unidentified nonsulfur compounds were significantly more abundant in males than in females. Quantitative comparison of 30 volatile urinary compounds showed several statistically significant differences between the sexes and individuals of the same sex. These findings suggest that ferrets may use urine marking for sex and individual recognitions. Ten of the 26 compounds identified in anal gland secretions from females and males were also found in urine. However, most of the major compounds (thietanes, dithiolanes, and indole) in anal glands were not present in urine. This suggests that urine may convey specific signals that differ from those of anal glands. Additionally, 10 volatiles (two aldehydes, five ketones, benzothiazole, 2-methylquinoline, and 4-methylquinazoline), not previously identified, were found in ferret anal gland secretions. Among the new compounds, o-aminoacetophenone was found only in males, while only traces of this compound were found in females. Similar results were previously obtained in anal glands of three other Mustela species. These findings provide new information about the constituents of urine and volatile components of anal gland secretions in ferrets.

Analysis of Na+, Cl-, K+, H+and NH4+ concentration gradients adjacent to the surface of anal papillae of the mosquitoAedes aegypti: application of self-referencing ion-selective microelectrodes

Ion concentration gradients adjacent to the surface of the anal papillae of larvae of the mosquito Aedes aegypti were measured using self-referencing ion-selective microelectrodes. The gradients were used to calculate estimates of ion fluxes into and out of the papillae. There was a net influx of Na+, Cl- and K+ from the bathing medium and a net efflux of acid and NH4+. No Ca2+ gradients were detectable. Na+ and Cl-influx occurred against a concentration gradient suggesting active transport. Although Na+, Cl- and NH4+gradients were uniform along the length of the papillae, the proximal regions of the papillae in vivo revealed significantly higher H+and K+ gradients compared with distal regions. The calculated ion fluxes at the papillae are sufficient for complete Na+,K+ and Cl- haemolymph replacement in ∼4 h with external ion concentrations of 5 mmol l-1. Ion gradients were also detected adjacent to the surface of isolated papillae; however, Na+and H+ gradients were higher, and Cl- gradients were lower relative to papillae in vivo. The results support previous findings that the anal papillae of mosquito larvae are important structures for ion regulation, and suggest that these structures may be used for the excretion of nitrogenous waste.

Relation between botulinum toxin and nitric oxide donors in the treatment of chronic anal fissure

Although the pathogenesis of fissure is not fully understood, we do know that surgical and/or pharmacological sphincterotomy promotes the healing of chronic anal fissures. A number of studies support the hypothesis that local ischemia is the reason for failure to heal in anal fissure. Therefore, sphincterotomy may work because it decreases anal canal resting pressure and enhances microcirculation at the fissure site. The vasomotor tone of arterioles controlled by metabolic and endothelial factors determines perfusion of tissue and fissure healing. In a novel approach, this paper proposes mechanisms for nitric oxide synthesis, regulation and action in the internal anal sphincter. The design demonstrates the direct interdependence between the activity mechanisms of botulinum toxin and nitric oxide. Endothelial lining can modulate not only vascular tone but also internal anal sphincter (IAS) tone. The application of botulinum toxin likely releases the blockage in glyceryl trinitrate bioactivation in smooth muscle cells and suppresses basal continuous sympathetic activity, causing IAS relaxation. Sufficient distension of the IAS during defecation also reduces the risk of trauma during defecation and complication after the trauma. Both eruption of tissue in the fissure region and release of contraction vessel mediators tend to arrest fissure healing.

Evidence for the role of angiotensin II biosynthesis in the rat internal anal sphincter tone

BACKGROUND & AIMS

The internal anal sphincter tone is important for anorectal continence. This study examined the role of angiotensin II as a neurohumoral signal for the myogenic tone in the internal anal sphincter.

METHODS

We determined the effect of angiotensin I, II, III, and IV and angiotensin-(1-7) on the basal tone of the rat internal anal sphincter smooth muscle before and after selective receptor antagonists and biosynthesis inhibitors. Selective pharmacological tools used were losartan (for the AT(1) receptor), PD123,319 (for AT(2)), A-779 [for angiotensin-(1-7)], captopril (for angiotensin-converting enzyme), and amastatin (for aminopeptidases A and N). Angiotensins were measured by using high-performance liquid chromatography/UV. Western blot studies were used to determine AT(1) and AT(2) receptors, ACE, and aminopeptidases A and N.

RESULTS

Angiotensin I, II, and III produced concentration-dependent contraction in the internal anal sphincter mediated by AT(1) receptors. However, in the higher concentrations (from 100 nM to 10 microM), angiotensin II showed an inhibitory effect via AT(2) receptors. Captopril (1 microM) inhibited the biosynthesis of angiotensin II in the internal anal sphincter, antagonized the contractile effects of angiotensin I, and, importantly, caused a decrease in the basal tone. Amastatin inhibited the effects of angiotensin II while augmenting those of angiotensin III. In contrast, angiotensin-(1-7) and angiotensin IV had only minor effects in the internal anal sphincter. Angiotensin I, II, and III; angiotensin-converting enzyme; aminopeptidase A and aminopeptidase n; at(1); and at(2) receptors were shown to be present in the internal anal sphincter.

CONCLUSIONS

Locally produced angiotensin II may partially regulate basal tone in the internal anal sphincter.

Inhibition of L-arginine transport by reactive oxygen species in rat anococcygeus muscle

The effect of L-arginine on nitrergic transmission and its alteration with reactive oxygen species (ROS) were investigated. L-arginine potentiated the relaxation response induced by electrical field stimulation in rat anococygeus muscle. This effect was inhibited by L-lysine, a cationic amino acid using y+ L and y+ transport systems in a similar way with L-arginine. The neutral amino acid L-leucine, which uses only y+ L system as a transport mechanism, inhibited this potentiation at only low frequency stimulation. Electrolysis of the physiological solution did not change the responses to electrical field stimulation, but inhibited the potentiation elicited by L-arginine that was prevented in the presence of mannitol and N-acetyl-L-cysteine. In conclusion, L-arginine is transported via y+ system predominantly to potentiate the relaxation response to nitrergic nerve stimulation in rat anococcygeus muscle. ROS, primarily hydroxyl radicals inhibited L-arginine-induced potentiation probably by interacting with the y+ amino acid transport system.

Sonic hedgehog and bone morphogenetic protein 4 expressions in the hindgut region of murine embryos with anorectal malformations

PURPOSE

The aim of this study was to determine the possible role of the retinoid-mediated signaling pathway in the pathogenesis of anorectal malformations (ARM). The authors investigated whether all-trans retinoic acid (ATRA) affects the expression pattern of Sonic hedgehog (Shh) and Bone morphogenetic protein 4 (BMP4), which play important roles in anorectal morphogenesis in vertebrates.

METHODS

Pregnant ICR strain mice were fed 100 mg/kg of ATRA on the ninth gestational day (E9). Embryos with or without administration of ATRA were obtained from the uteri between E12 and E16 and were fixed immediately in a 4% paraformaldehyde solution. Frozen sections were evaluated for concentric layers around the endodermal epithelium by H&E and immunohistochemistry using antibodies created specifically to act against Shh and BMP4.

RESULTS

More than 95% of the embryos administered ATRA had ARM; rectoprostatic urethral fistula, rectocloacal fistula, and short tail were the most frequent anomalies in the mouse embryos. On E14, normal mouse embryos had normal rectum and anus in which the epithelium of the anorectum was positive for Shh, and the mesenchyme was positive for BMP4. In the ARM embryos, however, the epithelium of the anorectum was negative for Shh, and the mesenchyme was also negative for BMP4.

CONCLUSIONS

In normal hindgut development, Shh from the epithelium induces BMP4 expression in the mesenchyme, which differentiates into the lamina propria and the submucosa. In ARM embryos, expressions of Shh and BMP4 could not be found in those regions of the hindgut. Therefore, these findings indicate that Shh and BMP4, which appear to play a crucial role in organogenesis of the hindgut, were disturbed in the cell signaling pathway between the epithelium and the mesenchyme layers.

Analysis of Anal Secretions from Phlaeothripine Thrips

The anal secretions of 16 phlaeothripine thrips species (Thysanoptera: Phlaeothripidae) were studied, including a reinvestigation of three species previously reported. A total of 37 components were detected, including hydrocarbons, acetates, terpenes, carboxylic acids, a quinone, an aromatic compound, and a pyranone compound. The secretions of all species were composed of some of these components, with Xylaplothrips inquilinus possessing as many as 11 components. Of these components, (Z)-9-octadecene, (Z)-9-nonadecene, nonadecadiene, octanoic acid, decanoic acid, geranial, neral, alpha-pinene, beta-pinene, caryophyllene, 2-hydroxy-6-methylbenzaldehyde, and two unidentified monoterpenes [UK-I (M+136) and UK-II (M+168)] were detected for the first time. The chemicals were species-specific; four Liothrips species and three Holothrips species could be distinguished from each other and their congeners by the GC profiles of the ether extracts of their anal secretions. The anal secretions of gall-inducing thrips commonly contained terpenes. of which citral (a mixture of geranial and neral) and beta-acaridial repelled ants or had antifungal activity. The findings suggest that these terpenes play a defensive role and prevent galls from fungal infestation. 3-Butanoyl-4-hydroxy-6-methyl-2H-pyran-2-one, found from three Holothrips spp., caused paralysis in ants. Chemical analysis of anal secretion components is a useful method for the classification of tubuliferan species that are difficult to distinguish on the basis of morphological characters.

Risk factors for carcinoma of the pelvic ileal pouch/anal canal in ulcerative colitis

Patients with ulcerative colitis who undergo proctocolectomy and an ileal anal anastomosis (IPAA) require surveillance; dysplasia and carcinoma occur in both the small intestinal mucosa of the ileal pouch and the retained rectal mucosa as early as 2 yr after ileostomy closure. This study evaluated risk factors for carcinoma (eg, dysplasia, p53 overexpression, labeling index, and aneuploidy) in the small intestinal and rectal mucosa. Thirty patients (age 14-64 yr) with ulcerative colitis and IPAA were studied. The mean duration of ulcerative colitis prior to IPAA was 3 yr (range 6 mo-21 yr). Patients were followed by annual endoscopy and biopsies of the ileal pouch and rectal mucosa. Sections of small intestine and rectal mucosa were evaluated for inflammation and dysplasia, and by immunohistochemical stains Ki-67 (MIB-1) for a labeling index and for p53. Ploidy determination was performed by flow cytometry. Active inflammation of the small intestinal mucosa and the rectal mucosa was frequent and the labeling index of both the pouch and rectal mucosa was abnormal. Two patients had changes indefinite for dysplasia, one involving the small bowel mucosa of the pouch and the other the retained rectal mucosa. Fifteen of the 30 patients had overexpression of p53, 9 from the pouch, and 6 from the rectal mucosa. Overexpression of p53 was seen in both of the patients with indefinite dysplasia. Aneuploidy was noted in 3 patients: two from the pouch and one from the rectal mucosa. All aneuploidic specimens were p53-positive, but negative for dysplasia. In conclusion, most biopsies of the ileal pouch and rectal mucosa were inflamed. The labeling indexes of the small bowel and rectal mucosa were higher than normal. The risk factors for carcinoma (dysplasia, overexpression of p53, and aneuploidy) occurred in the small intestinal and the rectal mucosa. Overexpression of p53 was noted in 16 patients, dysplasia only in 2. Therefore, p53 overexpression and aneuploidy should be considered in the evaluation of surveillance biopsies of patients with ulcerative colitis with IPAA, whereas dysplasia is an insensitive marker.

Receptor-independent activation of Rho-kinase-mediated calcium sensitisation in smooth muscle

1. The aim of this work was to determine whether Rho-kinase-mediated calcium sensitisation contributes to contractions of the mouse anococcygeus smooth muscle and, if so, whether the process was activated by receptor-dependent or receptor-independent mechanisms. 2. The Rho-kinase inhibitor Y27632 produced concentration-dependent decreases in tone raised by either the muscarinic receptor agonist carbachol (CCh), or the sarco-endoplasmic reticulum calcium ATPase inhibitor thapsigargin (Tg) (EC(50) values against CCh and Tg of 8.4+/-3.3 (n=6) and 6.1+/-2.1 (n=7) micro M, respectively). Pretreatment of tissues with Y27632 also inhibited contractions produced by 65 mM external potassium (69+/-7% (n=4) inhibition using 10 micro M Y27632). Y27632 had no effect on contractions produced by the inhibitor of smooth muscle myosin light-chain phosphatase, calyculin-A. 3. In beta-escin-permeabilised preparations, both CCh and Tg produced significant increases in tone over-and-above that produced by a combination of calcium (1 micro M) and GTP (100 micro M). These responses to CCh and Tg were inhibited by Y27632 (10 micro M). 4. Western blot analysis of fractionated tissue samples probed for RhoA immunoreactivity, indicated that both CCh and Tg were able to induce translocation of RhoA from the cytosol to the membrane. 5. These findings suggest that Rho-kinase-mediated calcium sensitisation is activated by both receptor-dependent and receptor-independent mechanisms in the mouse anococcygeus.

Gastrointestinal transit and stress response after laparoscopic vs conventional distal pancreatectomy in the canine model

BACKGROUND

Several authors have presented the feasibility of laparoscopic pancreatic surgery. However, the pathophysiological effect of laparoscopic pancreatic surgery is not well known.

METHODS

Ten mongrel dogs were randomly operated for laparoscopic and conventional distal pancreatectomy. Fed state gastrointestinal transit times were assessed using radiopaque markers. To assess surgical stress, we determined serum IL-1 and cortisol.

RESULTS

Postoperative mouth-to-anus transit time in the laparoscopic group was not prolonged while it was significantly prolonged in the conventional group compared with the baseline study, but no significant differences between groups were detected. First defecation was observed significantly earlier in the laparoscopic group. Serum cortisol levels were elevated significantly at 4 h after skin incision in both groups and decreased thereafter. In the laparoscopic group, they returned close to the normal level at 8 h after incision, but were still significantly higher in the conventional group. The level of IL-1 was elevated significantly higher in conventional group at 24 h after the skin incision.

CONCLUSION

Thus, we conclude that laparoscopic distal pancreatectomy demonstrated faster recovery of the bowel transit and less stress than conventional distal pancreatectomy in dogs.

Cyclooxygenase cloning in dogfish shark, Squalus acanthias, and its role in rectal gland Cl secretion

The present studies were carried out with the aims to determine the cDNA sequence for cyclooxygenase (COX) in an elasmobranch species and to study its role in regulation of chloride secretion in the perfused shark rectal gland (SRG). With the use of long primers (43 bp) derived from regions of homology between zebrafish and rainbow trout COX-2 genes, a 600-bp product was amplified from SRG and was found to be almost equally homologous to mammalian COX-1 and COX-2 (65%). The full-length cDNA sequence was obtained by 5'-RACE and by analyzing an EST clone generated by the EST Project of the Mt. Desert Island Biological Laboratory Marine DNA Sequencing Center. The longest open reading frame encodes a 593-amino acid protein that has 68 and 64% homology to mammalian COX-1 and COX-2, respectively. The gene and its protein product is designated as shark COX (sCOX). The key residues in the active site (Try(385), His(388), and Ser(530)) are conserved between the shark and mammalian COX. sCOX contains Val(523) that has been shown to be a key residue determining the sensitivity to COX-2-specific inhibitors including NS-398. The mRNA of sCOX, detected by RT-PCR, was found in all tissues tested, including rectal gland, kidney, spleen, gill, liver, brain, and heart, but not in fin. In the perfused SRG, vasoactive intestinal peptide (VIP) at 5 nM induced rapid and marked Cl(-) secretion (basal: <250 microeq x h(-1) x g(-1); peak response: 3,108 +/- 479 microeq x h(-1) x g(-1)). In the presence of 50 microM NS-398, both the peak response (2,131 +/- 307 microeq x h(-1) x g(-1)) and the sustained response to VIP were significantly reduced. When NS-398 was removed, there was a prompt recovery of chloride secretion to control values. In conclusion, we have cloned the first COX in an elasmobranch species (sCOX) and shown that sCOX inhibition suppresses VIP-stimulated chloride secretion in the perfused SRG.

Do Eurasian beavers smear their pelage with castoreum and anal gland secretion?

The scent-matching hypothesis postulates that scent marks provide an olfactory link between a resident owner and his territory, and that this enables intruding animals to recognize the chance of escalated conflicts. However, it is unclear if Eurasian beavers (Castor fiber) mark their own pelage with castoreum from their castor sacs (i.e., the same material used in territorial marking); and/or if beavers mark their pelage with anal gland secretion (AGS) from the anal glands to waterproof the pelage and to act as a "living-scent mark." Chemical analysis (gas chromatography and mass spectrometry) of hair samples from 22 live-trapped beavers revealed that castoreum compounds were not present in any samples, AGS compounds were found from 3 animals (13.6%) around the cloaca, and the compound squalene was found in all the samples. Beavers may release castoreum directly into the water when it meets an intruder. Thereby, the "scent mark" in the water can provide an olfactory link between a resident owner and his territory. Squalene, in contrast to AGS, may be essential for keeping beaver pelts water-repellant.

Volatile compounds in anal gland of Siberian weasels (Mustela sibirica) and steppe polecats (M. eversmanni)

The volatile constituents in anal gland secretions of two sympatric Mustela species, the Siberian weasel (M. sibirica) and steppe polecat (M. eversmanni), were studied by the headspace technique, followed by gas chromatography-mass spectrometry (GC-MS) analysis. Nine sulfur-containing compounds were identified. They were 2,2-dimethylthietane, (Z)- or (E)-2,4-dimethylthietane, (E)-2,3-dimethylthietane, 2-ethylthietane, (E)-2-ethyl-3-methylthietane, (Z)-2-ethyl-3-methylthietane, 2-propylthietane, 3,3-dimethyl-1,2-dithiacyclopentane, and (Z)-3,4-dimethyl-2,2-dithiacyclopentane. Among them, (E)-2-ethyl-3- methylthietanes, (Z)-2-ethyl-3-methylthietanes, and (Z)-3,4-dimethyl-1,2-dithiacyclopentane were present in the polecat but not in the weasel. The predominant compound was 2,2-dimethylthietane in the weasel and (E)- or (Z)-2,4-dimethylthietane in the polecat. These differences were consistent between the two species, regardless of sex and age and, therefore, could possibly be used for species recognition. In the weasel, 2-ethylthietane was found only in the female, and the relative abundance of several compounds was significantly different between males and females. In the polecat, although no sex-specific volatile compounds were found, males and females differed in the relative abundance of several of the compounds. In both species, the relative abundance of some compounds varied with age. We conclude that these volatile compounds can be used to communicate information about species, sex, and age.