Laparoscopic modified mesh rectopexy: medium-term results of a novel approach for external rectal prolapse

AIM

Rectal prolapse is a common and significantly debilitating condition. Surgical correction is usually required. The two most common abdominal approaches are ventral mesh rectopexy and posterior suture rectopexy. Both may be complicated, respectively, by either mesh-related complications or significant postoperative constipation. We report the outcome of a novel rectopexy operation which combines aspects of both the aforementioned approaches, for the treatment of external rectal prolapse (ERP).

METHOD

The technique involves laparoscopic partial posterior-lateral rectal mobilization of the rectum with posterior suture fixation to the sacral promontory and placement of an absorbable mesh in the rectovaginal space. Data were collected on postoperative complications, prolapse recurrence, mesh-related complications and the assessment of quality of life.

RESULTS

Eighty patients underwent a modified mesh rectopexy for ERP. Seventy-seven were women. The median age was 67.5 years. Almost a third had undergone a previous rectal prolapse repair. Recurrences were seen in 11 (13.8%). No mesh-related complications were seen. Eleven patients reported postoperative constipation.

CONCLUSION

The laparoscopic modified mesh rectopexy may be a safe and effective operation for the treatment of ERP.

Long-term outcome of sacral nerve stimulation for faecal incontinence

AIM

Sacral nerve stimulation (SNS) is a minimally invasive treatment for faecal incontinence (FI). We report our experience of patients who have undergone SNS for FI with a minimum of 5 years' follow-up. This is a single centre prospective observational study with the aim to assess the long-term function of SNS.

METHOD

All patients implanted with SNS were identified from our prospective database. The date of implantation, first and last clinic follow-up, surgical complications and St Mark's incontinence scores were abstracted and analysed.

RESULTS

From 1996 to 2014, 381 patients were considered for SNS. Of these, 256 patients met the study inclusion criteria. Median age at implantation was 52 years (range 18-81). The ratio of women to men was 205:51. Indications were urge FI (25%), passive FI (17.9%) and mixed FI (57%). The median of the incontinence score at baseline was 19/24 and this improved to 7/24 at the 6-month follow-up. Of the total cohort, 235 patients received a medium-term follow-up (median 110 months, range 12-270) with a median continence score of 10/24 which was also confirmed at the telephone long-term follow-up on 185 patients (132 months, range 60-276).

CONCLUSION

This study demonstrates that SNS is an effective treatment in the long term. SNS results in an improvement of validated scores for approximately 60% of patients; however, there is a significant reduction of efficacy over time due to underlying causes.

Small bowel obstruction secondary to diaphragmatic herniation following transabdominal cardiac ablation

We report an unusual case of strangulated diaphragmatic hernia secondary to a pericardial ablation, which resulted in necrosis of the incarcerated small bowel. Through a literature search, we have found a limited number of similar cases introducing a case series for this rare but potentially fatal condition.

The Renew® anal insert for passive faecal incontinence: a retrospective audit of our use of a novel device

AIM

The Renew® anal insert is a recent treatment for patients who suffer from passive faecal incontinence (FI). Our aim was to assess the effectiveness of the insert and patients' satisfaction with it.

METHOD

A retrospective audit of patients who were treated with the Renew® anal insert was undertaken. The St Mark's Incontinence Score was used to evaluate clinical outcome. Renew® size, the number of inserts used per day and per week had also been recorded. Subjective assessment of symptoms, how beneficial Renew® was and how satisfied patients were with the device were all recorded. Major events and side effects were also noted.

RESULTS

Thirty patients received Renew® as a treatment for passive incontinence in 2016. The median St Mark's Incontinence Score was 15 (range 7-18) at baseline and 10 (range 2-18) at first follow-up (P < 0.0001) at a median of 11 (range 8-14) weeks. Eleven (37%) patients used the regular size and 19 (63%) the large size. Patients used an average of 1.67 inserts per day (range 1-3) on an average of 3.58 days per week (1-7). Three patients reported a deterioration in symptoms, seven (23%) had no change and 20 (67%) showed a significant improvement. Six patients (20%) did not like the device while 24 (80%) liked it. Seventeen patients (57%) wanted to continue this treatment in the long term.

CONCLUSION

The Renew® device seems to be an acceptable and effective therapeutic option for passive FI. Further work is needed to compare it with other treatments and establish its position in the treatment pathway.

An N-Ethyl-N-Nitrosourea (ENU) Mutagenized Mouse Model for Autosomal Dominant Nonsyndromic Kyphoscoliosis Due to Vertebral Fusion

Kyphosis and scoliosis are common spinal disorders that occur as part of complex syndromes or as nonsyndromic, idiopathic diseases. Familial and twin studies implicate genetic involvement, although the causative genes for idiopathic kyphoscoliosis remain to be identified. To facilitate these studies, we investigated progeny of mice treated with the chemical mutagen N-ethyl-N-nitrosourea (ENU) and assessed them for morphological and radiographic abnormalities. This identified a mouse with kyphoscoliosis due to fused lumbar vertebrae, which was inherited as an autosomal dominant trait; the phenotype was designated as hereditary vertebral fusion (HVF) and the locus as Hvf. Micro-computed tomography (μCT) analysis confirmed the occurrence of nonsyndromic kyphoscoliosis due to fusion of lumbar vertebrae in HVF mice, consistent with a pattern of blocked vertebrae due to failure of segmentation. μCT scans also showed the lumbar vertebral column of HVF mice to have generalized disc narrowing, displacement with compression of the neural spine, and distorted transverse processes. Histology of lumbar vertebrae revealed HVF mice to have irregularly shaped vertebral bodies and displacement of intervertebral discs and ossification centers. Genetic mapping using a panel of single nucleotide polymorphic (SNP) loci arranged in chromosome sets and DNA samples from 23 HVF (eight males and 15 females) mice, localized Hvf to chromosome 4A3 and within a 5-megabase (Mb) region containing nine protein coding genes, two processed transcripts, three microRNAs, five small nuclear RNAs, three large intergenic noncoding RNAs, and 24 pseudogenes. However, genome sequence analysis in this interval did not identify any abnormalities in the coding exons, or exon-intron boundaries of any of these genes. Thus, our studies have established a mouse model for a monogenic form of nonsyndromic kyphoscoliosis due to fusion of lumbar vertebrae, and further identification of the underlying genetic defect will help elucidate the molecular mechanisms involved in kyphoscoliosis. © 2018 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Prediction of the free-surface elevation for rotational water waves using the recovery of pressure at the bed

This paper considers the pressure-streamfunction relationship for a train of regular water waves propagating on a steady current, which may possess an arbitrary distribution of vorticity, in two dimensions. The application of such work is to both near shore and offshore environments, and in particular, for linear waves we provide a description of the role which the pressure function on the seabed plays in determining the free-surface profile elevation. Our approach is shown to provide a good approximation for a range of current conditions.This article is part of the theme issue 'Nonlinear water waves'.

Genetic Variants in ERAP1 and ERAP2 Associated With Immune-Mediated Diseases Influence Protein Expression and the Isoform Profile

OBJECTIVE

Endoplasmic reticulum aminopeptidase 1 (ERAP-1) and ERAP-2, encoded on chromosome 5q15, trim endogenous peptides for HLA-mediated presentation to the immune system. Polymorphisms in ERAP1 and/or ERAP2 are strongly associated with several immune-mediated diseases with specific HLA backgrounds, implicating altered peptide handling and presentation as prerequisites for autoreactivity against an arthritogenic peptide. Given the thorough characterization of disease risk-associated polymorphisms that alter ERAP activity, this study aimed instead to interrogate the expression effect of chromosome 5q15 polymorphisms to determine their effect on ERAP isoform and protein expression.

METHODS

RNA sequencing and genotyping across chromosome 5q15 were performed to detect genetic variants in ERAP1 and ERAP2 associated with altered total gene and isoform-specific expression. The functional implication of a putative messenger RNA splice-altering variant on ERAP-1 protein levels was validated using mass spectrometry.

RESULTS

Polymorphisms associated with ankylosing spondylitis (AS) significantly influenced the transcript and protein expression of ERAP-1 and ERAP-2. Disease risk-associated polymorphisms in and around both genes were also associated with increased gene expression. Furthermore, key risk-associated ERAP1 variants were associated with altered transcript splicing, leading to allele-dependent alternate expression of 2 distinct isoforms and significant differences in the type of ERAP-1 protein produced.

CONCLUSION

In accordance with studies demonstrating that polymorphisms that increase aminopeptidase activity predispose to immune disease, the increased risk also attributed to increased expression of ERAP1 and ERAP2 supports the notion of using aminopeptidase inhibition to treat AS and other ERAP-associated conditions.

A retrospective review of 1495 patients with obstetric anal sphincter injuries referred for assessment of function and endoanal ultrasonography

AIM

Obstetric anal sphincter injuries are a significant risk factor for faecal incontinence. Correct identification and successful primary repair are important. The aim of this study was to review the outcome of all patients, with an obstetric anal sphincter injury, referred to our unit.

METHOD

This is a retrospective review of 1495 patients over a 12-year period. All had a third or fourth degree tear and were referred at 4-months postpartum.

RESULTS

Endoanal ultrasonography demonstrated residual sphincter defect in 792 (53%) and normal sphincters, with no evidence of repair, in 661 (44%). The majority of injuries involved both the external and internal sphincters (n = 501). Significant reductions in resting pressure and voluntary squeeze pressures were seen when those with a sphincter defect were compared to those with intact sphincters. However, there was no significant difference in the mean (SD) Cleveland Clinic faecal incontinence scores (5.8 (5.8) and 4.3 (5.5), p = 0.8).

CONCLUSION

Third and fourth degree tears appear to be over diagnosed. Primary repair appears to be unsuccessful in the majority of cases. There appears to be poor correlation between objective and subjective assessment of sphincter function.

Current practice of continence advisors in managing faecal incontinence in the United Kingdom: results of an online survey

AIM

To investigate the current practice of continence advisors in the United Kingdom.

METHOD

Continence advisors were contacted by email or letter to participate in a survey. The survey contained 27 questions which addressed the practice of each continence advisor, their knowledge of continence management and the adequacy of their training.

RESULTS

Two hundred and twenty-six out of a total of 448 continence advisors (50.4%), responded. One hundred and seventy (76.9%) advisors treated both faecal and urinary incontinence, 51 (23.1%) treated urinary incontinence. Thirty-six advisors (16.1%) were lone workers and 130 (58.6%) had more than 10 years' experience. The majority of the advisors (75.6%) performed a digital rectal examination as part of their assessment. Regarding the management of faecal incontinence, 148 prescribed suppositories, 127 offered enemas and 147 advised on rectal irrigation. Most of the advisors taught pelvic floor exercises (n = 207) and urge resistance techniques (n = 188). One hundred and fifty-nine (87.4%) prescribed the Peristeen Coloplast^® anal plug and 78 (47.6%) prescribed the Renew^® anal insert. Eighty-nine advisors (42.6%) felt they had not been adequately trained to provide a bowel continence service.

CONCLUSION

The majority of continence advisors in the UK manage faecal incontinence. They are able to initiate a broad range of conservative treatment options; however, almost half of the advisors who answered the survey felt inadequately trained and may be better supported by further training.

Early anti-inflammatory intervention ameliorates axial disease in the proteoglycan-induced spondylitis mouse model of ankylosing spondylitis

Background

Ankylosing spondylitis (AS) is characterised by immune-mediated arthritis and osteoproliferation, ultimately leading to joint ankylosis. Whether inflammation is necessary for osteoproliferation is controversial, fuelled by the unclear efficacy of anti-inflammatory treatments on radiographic progression. In proteoglycan-induced spondylitis (PGISp), a mouse model of AS, inflammation is the prerequisite for osteoproliferation as osteoproliferation was only observed following inflammation-driven intervertebral disc (IVD) destruction. We hypothesised that early intervention with a potent anti-inflammatory therapy would protect IVD integrity and consequently alter disease progression.

Methods

PGISp mice received vehicle or a combination of etanercept (ETN) plus prednisolone (PRD) therapy for 2 or 6 weeks initiated at an early disease stage. Peripheral arthritis was scored longitudinally. Spinal disease was assessed using a semi-quantitative histological scoring regimen including inflammation, joint destruction and excessive tissue formation.

Results

ETN + PRD therapy significantly delayed the onset of peripheral arthritis. IVD integrity was significantly protected when treatment was commenced in early disease. Six-weeks of treatment resulted in trends towards reductions in intervertebral joint damage and excessive tissue formation. IVD score distribution was dichotomized, likely reflecting the extent of axial disease at initiation of therapy. In the sub-group of mice with high IVD destruction scores, ETN + PRD treatment significantly reduced IVD destruction severity, inflammation and bone erosion and reduced cartilage damage and excessive tissue formation.

Conclusions

Early intervention with anti-inflammatory treatment not only improved inflammatory symptoms but also ameliorated structural damage of spine in PGISp mice. This preclinical observation suggests that early anti-inflammatory intervention may slow radiographic progression in AS patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1600-7) contains supplementary material, which is available to authorized users.

Genetic association of ankylosing spondylitis with TBX21 influences T-bet and pro-inflammatory cytokine expression in humans and SKG mice as a model of spondyloarthritis

OBJECTIVES

Ankylosing spondylitis (AS) is a highly heritable immune-mediated arthropathy. Inflammation in AS is poorly understood. TBX21 encodes T-bet, a transcription factor, lying within a locus with genome-wide significant association with AS. T-bet is implicated in innate and adaptive immunity. However, the role of T-bet in AS pathogenesis is unclear.

METHODS

We assessed the importance of T-bet in disease development and progression in peripheral blood mononuclear cells from 172 AS cases and 83 healthy controls carrying either risk or protective alleles of the peak AS-associated TBX21 single nucleotide polymorphism. Kinetics and localisation of T-bet expression in the SKG mouse model of spondyloarthropathy was examined, along with the impact of Tbx21 knockout on arthritis development in SKG mice.

RESULTS

Patients with AS had higher T-bet expression than healthy individuals, driven predominantly by natural killer and CD8+ T cells, with expression levels in CD8+ T cells completely distinguishing AS cases from healthy controls. T-bet expression was increased in AS cases carrying risk compared with protective alleles of rs11657479. In curdlan-treated SKG mice, T-bet expression increased early after disease initiation and persisted throughout the course of disease. There was marked reduction in gut and peripheral joint inflammation, and less IFNγ-producing and IL-17-producing CD8+ T cells, in Tbx21-/- compared with wild-type SKG mice.

CONCLUSIONS

AS-associated variants in TBX21 influence T-bet expression. T-bet+ innate and adaptive immune cells have altered IL-17 and IFNγ, and early activation marker CD69 expression than T-bet cells. This indicates that T-bet is a major component of inflammatory pathways of spondyloarthropathy in humans and mice.

Bilateral transcutaneous tibial nerve stimulation for chronic constipation

AIM

Chronic constipation is difficult to treat when symptoms are intractable. Colonic propulsion may be altered by distal neuromodulation but this is conventionally delivered percutaneously. Transcutaneous tibial nerve stimulation is noninvasive and cheap: this study aimed to assess its efficacy in chronic constipation.

METHOD

Eighteen patients (median age 46 years, 12 female) with chronic constipation were recruited consecutively. Conservative and behavioural therapy had failed to improve symptoms in all 18. Thirty minutes of daily bilateral transcutaneous tibial nerve stimulation was administered by each patient at home for 6 weeks. The primary outcome measure was a change in the Patient Assessment of Constipation Quality of Life (PAC-QoL) score. Change in Patient Assessment of Constipation Symptoms (PAC-SYM), weekly bowel frequency and visual analogue scale (VAS) score were also measured.

RESULTS

Fifteen patients (12 female) completed the trial. The PAC-QoL score improved significantly with treatment [pretreatment, median 2.95, interquartile range (IQR) 1.18; posttreatment, median 2.50, IQR 0.70; P = 0.047]. There was no change in PAC-SYM score (pretreatment, median 2.36, IQR 1.59; posttreatment, median 2.08, IQR 0.92; P = 0.53). Weekly stool frequency improved as did VAS score, but these did not reach statistical significance (P = 0.229 and 0.161). The PAC-QoL and PAC-SYM scores both improved in four (26%) patients. Two patients reported complete cure. There were no adverse events reported.

CONCLUSION

Bilateral transcutaneous tibial nerve stimulation appears to be effective in a quarter of patients with chronic constipation. Carefully selected patients with less severe disease may benefit more. This requires further study.

Inflammation-driven bone formation in a mouse model of ankylosing spondylitis: sequential not parallel processes

Background

Ankylosing spondylitis (AS) is an immune-mediated arthritis particularly targeting the spine and pelvis and is characterised by inflammation, osteoproliferation and frequently ankylosis. Current treatments that predominately target inflammatory pathways have disappointing efficacy in slowing disease progression. Thus, a better understanding of the causal association and pathological progression from inflammation to bone formation, particularly whether inflammation directly initiates osteoproliferation, is required.

Methods

The proteoglycan-induced spondylitis (PGISp) mouse model of AS was used to histopathologically map the progressive axial disease events, assess molecular changes during disease progression and define disease progression using unbiased clustering of semi-quantitative histology. PGISp mice were followed over a 24-week time course. Spinal disease was assessed using a novel semi-quantitative histological scoring system that independently evaluated the breadth of pathological features associated with PGISp axial disease, including inflammation, joint destruction and excessive tissue formation (osteoproliferation). Matrix components were identified using immunohistochemistry.

Results

Disease initiated with inflammation at the periphery of the intervertebral disc (IVD) adjacent to the longitudinal ligament, reminiscent of enthesitis, and was associated with upregulated tumor necrosis factor and metalloproteinases. After a lag phase, established inflammation was temporospatially associated with destruction of IVDs, cartilage and bone. At later time points, advanced disease was characterised by substantially reduced inflammation, excessive tissue formation and ectopic chondrocyte expansion. These distinct features differentiated affected mice into early, intermediate and advanced disease stages. Excessive tissue formation was observed in vertebral joints only if the IVD was destroyed as a consequence of the early inflammation. Ectopic excessive tissue was predominantly chondroidal with chondrocyte-like cells embedded within collagen type II- and X-rich matrix. This corresponded with upregulation of mRNA for cartilage markers Col2a1, sox9 and Comp. Osteophytes, though infrequent, were more prevalent in later disease.

Conclusions

The inflammation-driven IVD destruction was shown to be a prerequisite for axial disease progression to osteoproliferation in the PGISp mouse. Osteoproliferation led to vertebral body deformity and fusion but was never seen concurrent with persistent inflammation, suggesting a sequential process. The findings support that early intervention with anti-inflammatory therapies will be needed to limit destructive processes and consequently prevent progression of AS.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0805-0) contains supplementary material, which is available to authorized users.

Treatment of a mouse model of ankylosing spondylitis with exogenous sclerostin has no effect on disease progression

Background

No treatment to date is available which specifically targets bone formation in ankylosing spondylitis (AS). Several recent studies have shown that sclerostin (SOST), a Wnt inhibitor specific to osteocytes and chondrocytes, is down-regulated in AS patients. This suggests Wnt signalling may be upregulated, and application of exogenous recombinant SOST (rSOST) may inhibit Wnt signalling and slow pathological bone formation.

Methods

The proteoglycan-induced spondylitis (PGISp) mouse model in which we have previously demonstrated downregulated SOST expression, was used for this study. Mice were injected with 2.5ug rSOST/day for a period of 8 weeks following induction of disease. Axial skeleton disease development was assessed by histology and skeletal changes examined using DEXA.

Results

rSOST treatment had no effect on peripheral or axial disease development, bone density or disease severity. Injected rSOST was stable over 8 h and residual levels were evident 24 h after injection, resulting in a cumulative increase in SOST serum levels over the treatment time course. Immunohistochemical examination of SOST levels within the joints in non-rSOST treated PGISp mice showed a significant decrease in the percentage of positive osteocytes in the unaffected joints compared to the affected joints, while no difference was seen in rSOST treated mice. This suggests that rSOST treatment increases the number of SOST-positive osteocytes in unaffected joints but not affected joints, despite having no impact on the number of joints affected by disease.

Conclusions

Although not disease-modifying, rSOST treatment did appear to regulate SOST levels in the joints suggesting biological activity. Further dose response studies are required and SOST may require modifications to improve its bone targeting ability in order to affect tissue formation to a meaningful level in this model.

A review of sacral nerve stimulation for faecal incontinence following rectal surgery and radiotherapy

AIM

Faecal incontinence may occur following rectal surgery and/or radiotherapy for rectal cancer. The aim of this paper was to review the evidence to support the use of sacral nerve stimulation (SNS) for patients with incontinence who had undergone rectal surgery or received rectal radiotherapy.

METHOD

A search was performed of PubMed, Medline and Embase. All studies which reported the outcome of SNS in patients who had undergone a rectal resection or radiotherapy were reviewed.

RESULTS

The first report of SNS following rectal surgery was in 2002. Since then seven further studies have described its effect in patients who have undergone anterior resection or pelvic radiotherapy. The total number of patients was 57. All studies were single group series, which ranged in size from one to 15 patients. The follow-up ranged from 1 to 36 months. The success of peripheral nerve evaluation ranged from 47% to 100%. Permanent SNS improved the symptoms and in some studies this was reflected in improved quality of life. The wide variation of patient factors, operations performed, the dose of radiotherapy given and time from operation makes interpretation of the results difficult.

CONCLUSION

Larger studies with better patient selection are needed to investigate the effect of SNS on incontinence following radiotherapy or rectal surgery.

A double-blinded randomized multicentre study to investigate the effect of changes in stimulation parameters on sacral nerve stimulation for constipation

AIM

Sacral nerve stimulation (SNS) may be offered to patients with constipation who have failed to improve with conservative treatment. The response to SNS is variable, with a significant loss of efficacy in some patients. An increased frequency of stimulation may improve the efficacy of SNS for faecal incontinence. This study aimed to see if alteration of the pulse width or frequency improved the outcome for those with constipation.

METHOD

Eleven patients with constipation currently being treated by SNS were recruited from three centres. They were randomized to five different protocols of stimulation each applied for 5 weeks. Group 1 used standard settings (pulse width 210 μs, frequency 14 Hz); in the other four groups (Groups 2-5) the pulse width and/or frequency were halved or doubled. Patients and investigators were blinded to the group allocation.

RESULTS

The Cleveland Clinic constipation score varied significantly between the five groups. Group 1 achieved the lowest score mean (± SD) 13.4 (± 4.4) (P = 0.03). The number of digitations per defaecation was the lowest in Group 4, 90 μs and 14 Hz (P < 0.01). No other variable changed significantly. Standard settings were the most preferred by the recruited patients.

CONCLUSION

Alteration of pulse width or frequency of stimulation had no significant effect on the outcome of SNS for constipation.

ERAP2 functional knockout in humans does not alter surface heavy chains or HLA-B27, inflammatory cytokines or endoplasmic reticulum stress markers

INTRODUCTION

Single nucleotide polymorphisms in ERAP2 are strongly associated with ankylosing spondylitis (AS). One AS-associated single nucleotide polymorphism, rs2248374, causes a truncated ERAP2 protein that is degraded by nonsense-mediated decay. Approximately 25% of the populations of European ancestry are therefore natural ERAP2 knockouts. We investigated the effect of this associated variant on HLA class I allele presentation, surface heavy chains, endoplasmic reticulum (ER) stress markers and cytokine gene transcription in AS.

METHODS

Patients with AS and healthy controls with either AA or GG homozygous status for rs2248374 were studied. Antibodies to CD14, CD19-ECD, HLA-A-B-C, Valpha7.2, CD161, anti-HC10 and anti-HLA-B27 were used to analyse peripheral blood mononuclear cells. Expression levels of ER stress markers (GRP78 and CHOP) and proinflammatory genes (tumour necrosis factor (TNF), IL6, IL17 and IL22) were assessed by qPCR.

RESULTS

There was no significant difference in HLA-class I allele presentation or major histocompatibility class I heavy chains or ER stress markers GRP78 and CHOP or proinflammatory gene expression between genotypes for rs2248374 either between cases, between cases and controls, and between controls.

DISCUSSION

Large differences were not seen in HLA-B27 expression or cytokine levels between subjects with and without ERAP2 in AS cases and controls. This suggests that ERAP2 is more likely to influence AS risk through other mechanisms.

N-ethyl-N-Nitrosourea (ENU) induced mutations within the klotho gene lead to ectopic calcification and reduced lifespan in mouse models

Ectopic calcification (EC), which is the pathological deposition of calcium and phosphate in extra-skeletal tissues, may be associated with hypercalcaemic and hyperphosphataemic disorders, or it may occur in the absence of metabolic abnormalities. In addition, EC may be inherited as part of several monogenic disorders and studies of these have provided valuable insights into the metabolic pathways regulating mineral metabolism. For example, studies of tumoural calcinosis, a disorder characterised by hyperphosphataemia and progressive EC, have revealed mutations of fibroblast growth factor 23 (FGF23), polypeptide N-acetyl galactosaminyltransferase 3 (GALNT3) and klotho (KL), which are all part of a phosphate-regulating pathway. However, such studies in humans are limited by the lack of available large families with EC, and to facilitate such studies we assessed the progeny of mice treated with the chemical mutagen N-ethyl-N-nitrosourea (ENU) for EC. This identified two mutants with autosomal recessive forms of EC, and reduced lifespan, designated Ecalc1 and Ecalc2. Genetic mapping localized the Ecalc1 and Ecalc2 loci to a 11.0 Mb region on chromosome 5 that contained the klotho gene (Kl), and DNA sequence analysis identified nonsense (Gln203Stop) and missense (Ile604Asn) Kl mutations in Ecalc1 and Ecalc2 mice, respectively. The Gln203Stop mutation, located in KL1 domain, was severely hypomorphic and led to a 17-fold reduction of renal Kl expression. The Ile604Asn mutation, located in KL2 domain, was predicted to impair klotho protein stability and in vitro expression studies in COS-7 cells revealed endoplasmic reticulum retention of the Ile604Asn mutant. Further phenotype studies undertaken in Ecalc1 (kl203X/203X) mice demonstrated elevations in plasma concentrations of phosphate, FGF23 and 1,25-dihydroxyvitamin D. Thus, two allelic variants of Kl that develop EC and represent mouse models for tumoural calcinosis have been established.

Rorα deficiency and decreased adiposity are associated with induction of thermogenic gene expression in subcutaneous white adipose and brown adipose tissue

The Rar-related orphan receptor-α (Rorα) is a nuclear receptor that regulates adiposity and is a potential regulator of energy homeostasis. We have demonstrated that the Rorα-deficient staggerer (sg/sg) mice display a lean and obesity-resistant phenotype. Adaptive Ucp1-dependent thermogenesis in beige/brite and brown adipose tissue serves as a mechanism to increase energy expenditure and resist obesity. DEXA and MRI analysis demonstrated significantly decreased total fat mass and fat/lean mass tissue ratio in male chow-fed sg/sg mice relative to wt mice. In addition, we observed increased Ucp1 expression in brown adipose and subcutaneous white adipose tissue but not in visceral adipose tissue from Rorα-deficient mice. Moreover, this was associated with significant increases in the expression of the mRNAs encoding the thermogenic genes (i.e., markers of brown and beige adipose) Pparα, Errα, Dio2, Acot11/Bfit, Cpt1β, and Cidea in the subcutaneous adipose in the sg/sg relative to WT mice. These changes in thermogenic gene expression involved the significantly increased expression of the (cell-fate controlling) histone-lysine N-methyltransferase 1 (Ehmt1), which stabilizes the Prdm16 transcriptional complex. Moreover, primary brown adipocytes from sg/sg mice displayed a higher metabolic rate, and further analysis was consistent with increased uncoupling. Finally, core body temperature analysis and infrared thermography demonstrated that the sg/sg mice maintained greater thermal control and cold tolerance relative to the WT littermates. We suggest that enhanced Ucp1 and thermogenic gene expression/activity may be an important contributor to the lean, obesity-resistant phenotype in Rorα-deficient mice.

Senescent human hepatocytes express a unique secretory phenotype and promote macrophage migration

AIM: To develop a model of stress-induced senescence to study the hepatocyte senescence associated secretory phenotype (SASP).

METHODS: Hydrogen peroxide treatment was used to induce senescence in the human HepG2 hepatocyte cell line. Senescence was confirmed by cytochemical staining for a panel of markers including Ki67, p21, heterochromatin protein 1β, and senescence-associated-β-galactosidase activity. Senescent hepatocytes were characterised by gene expression arrays and quantitative polymerase chain reaction (qPCR), and conditioned media was used in proteomic analyses, a human chemokine protein array, and cell migration assays to characterise the composition and function of the hepatocyte SASP.

RESULTS: Senescent hepatocytes induced classical markers of senescence (p21, heterochromatin protein 1β, and senescence-associated-β-galactosidase activity); and downregulated the proliferation marker, Ki67. Hepatocyte senescence induced a 4.6-fold increase in total secreted protein (P = 0.06) without major alterations in the protein profile. Senescence-induced genes were identified by microarray (Benjamini Hochberg-corrected P < 0.05); and, consistent with the increase in secreted protein, gene ontology analysis revealed a significant enrichment of secreted proteins among inducible genes. The hepatocyte SASP included characteristic factors such as interleukin (IL)-8 and IL-6, as well as novel components such as SAA4, IL-32 and Fibrinogen, which were validated by qPCR and/or chemokine protein array. Senescent hepatocyte-conditioned medium elicited migration of inflammatory (granulocyte-macrophage colony stimulating factor, GM-CSF-derived), but not non-inflammatory (CSF-1-derived) human macrophages (P = 0.022), which could contribute to a pro-inflammatory microenvironment in vivo, or facilitate the clearance of senescent cells.

CONCLUSION: Our novel model of hepatocyte senescence provides insights into mechanisms by which senescent hepatocytes may promote chronic liver disease pathogenesis.

Resveratrol does not benefit patients with nonalcoholic fatty liver disease

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD), characterized by accumulation of hepatic triglycerides (steatosis), is associated with abdominal obesity, insulin resistance, and inflammation. Although weight loss via calorie restriction reduces features of NAFLD, there is no pharmacologic therapy. Resveratrol is a polyphenol that prevents high-energy diet-induced steatosis and insulin resistance in animals by up-regulating pathways that regulate energy metabolism. We performed a placebo-controlled trial to assess the effects of resveratrol in patients with NAFLD.

METHODS

Overweight or obese men diagnosed with NAFLD were recruited from hepatology outpatient clinics in Brisbane, Australia from 2011 through 2012. They were randomly assigned to groups given 3000 mg resveratrol (n = 10) or placebo (n = 10) daily for 8 weeks. Outcomes included insulin resistance (assessed by the euglycemic-hyperinsulinemic clamp), hepatic steatosis, and abdominal fat distribution (assessed by magnetic resonance spectroscopy and imaging). Plasma markers of inflammation, as well as metabolic, hepatic, and antioxidant function, were measured; transcription of target genes was measured in peripheral blood mononuclear cells. Resveratrol pharmacokinetics and safety were assessed.

RESULTS

Eight-week administration of resveratrol did not reduce insulin resistance, steatosis, or abdominal fat distribution when compared with baseline. No change was observed in plasma lipids or antioxidant activity. Levels of alanine and aspartate aminotransferases increased significantly among patients in the resveratrol group until week 6 when compared with the placebo group. Resveratrol did not significantly alter transcription of NQO1, PTP1B, IL6, or HO1 in peripheral blood mononuclear cells. Resveratrol was well-tolerated.

CONCLUSIONS

Eight weeks administration of resveratrol did not significantly improve any features of NAFLD, compared with placebo, but it increased hepatic stress, based on observed increases in levels of liver enzymes. Further studies are needed to determine whether agents that are purported to mimic calorie restriction, such as resveratrol, are safe and effective for complications of obesity. Clinical trials registration no: ACTRN12612001135808.

Disease-associated polymorphisms in ERAP1 do not alter endoplasmic reticulum stress in patients with ankylosing spondylitis

The mechanism by which human leukocyte antigen B27 (HLA-B27) contributes to ankylosing spondylitis (AS) remains unclear. Genetic studies demonstrate that association with and interaction between polymorphisms of endoplasmic reticulum aminopeptidase 1 (ERAP1) and HLA-B27 influence the risk of AS. It has been hypothesised that ERAP1-mediated HLA-B27 misfolding increases endoplasmic reticulum (ER) stress, driving an interleukin (IL) 23-dependent, pro-inflammatory immune response. We tested the hypothesis that AS-risk ERAP1 variants increase ER-stress and concomitant pro-inflammatory cytokine production in HLA-B27(+) but not HLA-B27(-) AS patients or controls. Forty-nine AS cases and 22 healthy controls were grouped according to HLA-B27 status and AS-associated ERAP1 rs30187 genotypes: HLA-B27(+)ERAP1(risk), HLA-B27(+)ERAP1(protective), HLA-B27(-)ERAP1(risk) and HLA-B27(-)ERAP1(protective). Expression levels of ER-stress markers GRP78 (8 kDa glucose-regulated protein), CHOP (C/EBP-homologous protein) and inflammatory cytokines were determined in peripheral blood mononuclear cell and ileal biopsies. We found no differences in ER-stress gene expression between HLA-B27(+) and HLA-B27(-) cases or healthy controls, or between cases or controls stratified by carriage of ERAP1 risk or protective alleles in the presence or absence of HLA-B27. No differences were observed between expression of IL17A or TNF (tumour necrosis factor) in HLA-B27(+)ERAP1(risk), HLA-B27(+)ERAP1(protective) and HLA-B27(-)ERAP1(protective) cases. These data demonstrate that aberrant ERAP1 activity and HLA-B27 carriage does not alter ER-stress levels in AS, suggesting that ERAP1 and HLA-B27 may influence disease susceptibility through other mechanisms.

Interleukin-23 mediates the intestinal response to microbial β-1,3-glucan and the development of spondyloarthritis pathology in SKG mice

OBJECTIVE

Spondyloarthritides (SpA) occur in 1% of the population and include ankylosing spondylitis (AS) and arthropathy of inflammatory bowel disease (IBD), with characteristic spondylitis, arthritis, enthesitis, and IBD. Genetic studies implicate interleukin-23 (IL-23) receptor signaling in the development of SpA and IBD, and IL-23 overexpression in mice is sufficient for enthesitis, driven by entheseal-resident T cells. However, in genetically prone individuals, it is not clear where IL-23 is produced and how it drives the SpA syndrome, including IBD or subclinical gut inflammation of AS. Moreover, it is unclear why specific tissue involvement varies between patients with SpA. We undertook this study to determine the location of IL-23 production and its role in SpA pathogenesis in BALB/c ZAP-70(W163C)-mutant (SKG) mice injected intraperitoneally with β-1,3-glucan (curdlan).

METHODS

Eight weeks after curdlan injection in wild-type or IL-17A(-/-) SKG or BALB/c mice, pathology was scored in tissue sections. Mice were treated with anti-IL-23 or anti-IL-22. Cytokine production and endoplasmic reticulum (ER) stress were determined in affected organs.

RESULTS

In curdlan-treated SKG mice, arthritis, enthesitis, and ileitis were IL-23 dependent. Enthesitis was specifically dependent on IL-17A and IL-22. IL-23 was induced in the ileum, where it amplified ER stress, goblet cell dysfunction, and proinflammatory cytokine production. IL-17A was pathogenic, while IL-22 was protective against ileitis. IL-22+CD3- innate-like cells were increased in lamina propria mononuclear cells of ileitis-resistant BALB/c mice, which developed ileitis after curdlan injection and anti-IL-22.

CONCLUSION

In response to systemic β-1,3-glucan, intestinal IL-23 provokes local mucosal dysregulation and cytokines driving the SpA syndrome, including IL-17/IL-22-dependent enthesitis. Innate IL-22 production promotes ileal tolerance.

A pilot study of chronic pudendal nerve stimulation for faecal incontinence for those who have failed sacral nerve stimulation

BACKGROUND

Sacral nerve stimulation (SNS) is used as a first-line treatment for faecal incontinence when conservative measures have failed. However, one-third of patients fail to benefit from this treatment. We hypothesised that sacral afferent stimulation can be maximised using pudendal nerve stimulation (PNS) and this may be of benefit in this patient group. The aim of this study was to assess chronic PNS for those who failed to improve with SNS.

METHODS

Ten patients who had failed SNS were recruited. All underwent percutaneous insertion of a stimulation lead with four-electrode array adjacent to the pudendal nerve. Continuous bipolar stimulation was administered using an external pulse generator over a 3-week period. Those who experienced a ≥50% reduction in the frequency of incontinent episodes over this period proceeded to chronic stimulation with an implantable pulse generator.

RESULTS

Five patients experienced a ≥50% reduction of incontinent episodes during test stimulation and proceeded to chronic stimulation. In these five patients, at a median (range) follow-up of 24 (6-36) months, the median (inter quartile range) frequency of incontinent episodes reduced from 5 (18.25) to 2.5 (3) per week (p = 0.043). Three patients maintained a ≥50% improvement in soiling. There was an improvement in the St Mark's continence Score from 19 (15-24) to 16 (13-19), p = 0.042. There were no significant changes in ability to defer defecation or in quality of life scores.

CONCLUSIONS

Pudendal nerve stimulation failed to improve the symptoms in the majority of patient who had failed SNS. Only a third experienced any improvement.

A brilliant breakthrough in OI type V

Interferon-induced transmembrane protein 5 or bone-restricted ifitm-like gene (Bril) was first identified as a bone gene in 2008, although no in vivo role was identified at that time. A role in human bone has now been demonstrated with a number of recent studies identifying a single point mutation in Bril as the causative mutation in osteogenesis imperfecta type V (OI type V). Such a discovery suggests a key role for Bril in skeletal regulation, and the completely novel nature of the gene raises the possibility of a new regulatory pathway in bone. Furthermore, the phenotype of OI type V has unique and quite divergent features compared with other forms of OI involving defects in collagen biology. Currently it appears that the underlying genetic defect in OI type V may be unrelated to collagen regulation, which also raises interesting questions about the classification of this form of OI. This review will discuss current knowledge of OI type V, the function of Bril, and the implications of this recent discovery.

Expression profiling in spondyloarthropathy synovial biopsies highlights changes in expression of inflammatory genes in conjunction with tissue remodelling genes

BACKGROUND

In the spondyloarthropathies, the underlying molecular and cellular pathways driving disease are poorly understood. By undertaking a study in knee synovial biopsies from spondyloarthropathy (SpA) and ankylosing spondylitis (AS) patients we aimed to elucidate dysregulated genes and pathways.

METHODS

RNA was extracted from six SpA, two AS, three osteoarthritis (OA) and four normal control knee synovial biopsies. Whole genome expression profiling was undertaken using the Illumina DASL system, which assays 24000 cDNA probes. Differentially expressed candidate genes were then validated using quantitative PCR and immunohistochemistry.

RESULTS

Four hundred and sixteen differentially expressed genes were identified that clearly delineated between AS/SpA and control groups. Pathway analysis showed altered gene-expression in oxidoreductase activity, B-cell associated, matrix catabolic, and metabolic pathways. Altered "myogene" profiling was also identified. The inflammatory mediator, MMP3, was strongly upregulated (5-fold) in AS/SpA samples and the Wnt pathway inhibitors DKK3 (2.7-fold) and Kremen1 (1.5-fold) were downregulated.

CONCLUSIONS

Altered expression profiling in SpA and AS samples demonstrates that disease pathogenesis is associated with both systemic inflammation as well as local tissue alterations that may underlie tissue damaging modelling and remodelling outcomes. This supports the hypothesis that initial systemic inflammation in spondyloarthropathies transfers to and persists in the local joint environment, and might subsequently mediate changes in genes directly involved in the destructive tissue remodelling.

Sclerostin regulates release of bone mineral by osteocytes by induction of carbonic anhydrase 2

The osteocyte product sclerostin is emerging as an important paracrine regulator of bone mass. It has recently been shown that osteocyte production of receptor activator of NF-κB ligand (RANKL) is important in osteoclastic bone resorption, and we reported that exogenous treatment of osteocytes with sclerostin can increase RANKL-mediated osteoclast activity. There is good evidence that osteocytes can themselves liberate mineral from bone in a process known as osteocytic osteolysis. In the current study, we investigated sclerostin-stimulated mineral dissolution by human primary osteocyte-like cells (hOCy) and mouse MLO-Y4 cells. We found that sclerostin upregulated osteocyte expression of carbonic anhydrase 2 (CA2/Car2), cathepsin K (CTSK/Ctsk), and tartrate-resistant acid phosphatase (ACP5/Acp5). Because acidification of the extracellular matrix is a critical step in the release of mineral from bone, we further examined the regulation by sclerostin of CA2. Sclerostin stimulated CA2 mRNA and protein expression in hOCy and in MLO-Y4 cells. Sclerostin induced a decrease in intracellular pH (pHi) in both cell types as well as a decrease in extracellular pH (pHo) and the release of calcium ions from mineralized substrate. These effects were reversed in the co-presence of the carbonic anhydrase inhibitor, acetozolamide. Car2-siRNA knockdown in MLO-Y4 cells significantly inhibited the ability of sclerostin to both reduce the pHo and release calcium from a mineralized substrate. Knockdown in MLO-Y4 cells of each of the putative sclerostin receptors, Lrp4, Lrp5 and Lrp6, using siRNA, inhibited the sclerostin induction of Car2, Catk and Acp5 mRNA, as well as pHo and calcium release. Consistent with this activity of sclerostin resulting in osteocytic osteolysis, human trabecular bone samples treated ex vivo with recombinant human sclerostin for 7 days exhibited an increased osteocyte lacunar area, an effect that was reversed by the co-addition of acetozolamide. These findings suggest a new role for sclerostin in the regulation of perilacunar mineral by osteocytes.

A pilot study to compare daily with twice weekly transcutaneous posterior tibial nerve stimulation for faecal incontinence

AIM

Posterior tibial nerve stimulation (PTNS) has been shown to improve faecal incontinence in the short term. The optimal treatment regimen is unclear with wide variations in protocol reported in the literature. The study aimed to assess two different regimens of transcutaneous PTNS and to establish whether increasing the frequency of stimulation increases the effectiveness.

METHOD

Thirty patients were randomized to receive once daily or twice weekly PTNS for a 6-week period. The treatment was carried out by the patient at home after instruction. The primary investigator was blinded to the patient allocation until the study had ended, at which point the symptoms were assessed. No further stimulation was given after 6 weeks and the patients were followed until their symptoms returned to the pre-stimulation state (baseline). The primary outcome measure was a change in the frequency of incontinent episodes.

RESULTS

Three patients in the daily group and none in the twice weekly group achieved complete continence. Only patients from the daily group showed a significant reduction in median (interquartile range) incontinent episodes per week from 5 (11.13) to 3.5 (4.31) (P = 0.025). There was no significant change in the frequency of defaecation nor in the ability to defer defaecation. Patients in the daily group experienced a significant improvement in the domains of lifestyle [2.2 (1.7) to 2.6 (1.65), P = 0.04] and embarrassment [1.7 (0.85) to 2.15 (0.4), P = 0.04] on the Rockwood Fecal Incontinence Quality of Life assessment. No adverse events were reported.

CONCLUSION

Transcutaneous PTNS can safely be used by the patient at home. Daily treatment may be more effective than twice weekly treatment. Larger studies are needed to investigate this further.

A pilot study of transcutaneous sacral nerve stimulation for faecal incontinence

AIM

Although effective in faecal incontinence (FI), sacral nerve stimulation (SNS) is expensive and requires two procedures. It carries a small risk of infection and electrode migration. Transcutaneous SNS is noninvasive and cheap. Two small studies have reported the results when applied to segments S3 but there is no information on its effectiveness when applied to the whole sacral area.

METHOD

A pilot study was carried out of self-administered transcutaneous SNS given over a 4-week period for 12 h a day. A 2-week bowel diary was kept for the final 2 weeks and compared with baseline. Patients were assessed using the St Mark's Incontinence Score, a visual analogue scale assessing satisfaction with bowel habit, the Rockwood FI Quality of Life (QOL) score and SF-36 QOL score.

RESULTS

Of the 10 patients recruited, two achieved complete continence. There was a statistically significant reduction in the median (interquartile range) frequency of incontinent episodes per week from 9.5 (7.5) to 3 (7.38) (P = 0.03), and in the median frequency of defaecation per week from 25.5 (19.5) to 14.5 (14.9) (P = 0.007). There was a statistically significant improvement in the median ability to defer defaecation from 1 (1.25) to 4.5 (4.5) min (P = 0.02). There was also a statistically significant improvement in the St Marks Incontinence Score from 20 (5.25) to 14.5 (8.0) (P = 0.01) and in the bowel habit satisfaction visual analogue scale from 8.5 (20) to 45 (33) (P = 0.008). There was no change in the Rockwood FI QOL or SF-36 QOL scores. No complications were reported.

CONCLUSION

Transcutaneous SNS appears to be an effective and safe treatment for FI. Larger controlled studies are needed to explore this further.

Transgenic muscle-specific Nor-1 expression regulates multiple pathways that effect adiposity, metabolism, and endurance

The mRNA encoding Nor-1/NR4A3 is rapidly and strikingly induced by β2-adrenergic signaling in glycolytic and oxidative skeletal muscle. In skeletal muscle cells, Nor-1 expression is important for the regulation of oxidative metabolism. Transgenic skeletal muscle-specific expression of activated Nor-1 resulted in the acquisition of an endurance phenotype, an increase in type IIA/X oxidative muscle fibers, and increased numbers of mitochondria. In the current study, we used dual-energy x-ray absorptiometry and magnetic resonance imaging analysis to demonstrate decreased adiposity in transgenic (Tg) Nor-1 mice relative to that in wild-type littermates. Furthermore, the Tg-Nor-1 mice were resistant to diet-induced weight gain and maintained fasting glucose at normoglycemic levels. Expression profiling and RT-quantitative PCR analysis revealed significant increases in genes involved in glycolysis, the tricarboxylic acid cycle, oxidative phosphorylation, fatty acid oxidation, and glycogen synthesis, in concordance with the lean phenotype. Moreover, expression profiling identified several Z-disc and sarcomeric binding proteins that modulate fiber type phenotype and endurance, eg, α-actinin-3. In addition, we demonstrated that the Tg-Nor-1 mouse line has significantly higher glycogen content in skeletal muscle relative to that in wild-type littermates. Finally, we identified a decreased NAD(+)/NADH ratio with a concordant increase in peroxisome proliferator-activated receptor γ coactivator-1α1 protein/mRNA expression. Increased NADH was associated with an induction of the genes involved in the malate-aspartate shuttle and a decrease in the glycerol 3-phosphate shuttle, which maximizes aerobic ATP production. In conclusion, skeletal muscle-specific Nor-1 expression regulates genes and pathways that regulate adiposity, muscle fiber type metabolic capacity, and endurance.

Brief report: high-throughput sequencing of IL23R reveals a low-frequency, nonsynonymous single-nucleotide polymorphism that is associated with ankylosing spondylitis in a Han Chinese population

OBJECTIVE

Ankylosing spondylitis (AS) is a highly heritable common inflammatory arthritis that targets the spine and sacroiliac joints of the pelvis, causing pain and stiffness and leading eventually to joint fusion. Although previous studies have shown a strong association of IL23R with AS in white Europeans, similar studies in East Asian populations have shown no association with common variants of IL23R, suggesting either that IL23R variants have no role or that rare genetic variants contribute. The present study was undertaken to screen IL23R to identify rare variants associated with AS in Han Chinese.

METHODS

A 170-kb region containing IL23R and its flanking regions was sequenced in 50 patients with AS and 50 ethnically matched healthy control subjects from a Han Chinese population. In addition, the 30-kb region of peak association in white Europeans was sequenced in 650 patients with AS and 1,300 healthy controls. Validation genotyping was undertaken in 846 patients with AS and 1,308 healthy controls.

RESULTS

We identified 1,047 variants, of which 729 were not found in the dbSNP genomic build 130. Several potentially functional rare variants in IL23R were identified, including one nonsynonomous single-nucleotide polymorphism (nsSNP), Gly(149) Arg (position 67421184 GA on chromosome 1). Validation genotyping showed that the Gly(149) Arg variant was associated with AS (odds ratio 0.61, P = 0.0054).

CONCLUSION

This is the first study to implicate rare IL23R variants in the pathogenesis of AS. The results identified a low-frequency nsSNP with predicted loss-of-function effects that was protectively associated with AS in Han Chinese, suggesting that decreased function of the interleukin-23 (IL-23) receptor protects against AS. These findings further support the notion that IL-23 signaling has an important role in the pathogenesis of AS.

Sacral nerve stimulation: an effective treatment for chronic functional anal pain?

AIM

Chronic idiopathic anal pain is a common condition of unknown aetiology. Patients may have co-existing psychiatric disorders and existing treatments are often ineffective. A small number of published case reports suggest that sacral nerve stimulation (SNS) could treat this condition. This pilot study aimed to investigate the efficacy of SNS for the treatment of chronic anal pain.

METHOD

Ten patients with chronic idiopathic anal pain were recruited. All had failed to respond to conservative treatments. Clinical and psychological evaluation was performed in all patients prior to SNS. Temporary stimulation of the S3 foramina was performed for 3 weeks and outcome assessed by comparison of a pain score diary and visual analogue score obtained during stimulation and at baseline. Primary outcome was defined as a > 50% reduction in pain score.

RESULTS

Of the 10 patients recruited, five were found to have clinical depression. Four patients withdrew from the study prior to testing and six underwent peripheral nerve evaluation (PNE). Three patients had > 50% reduction in pain score and progressed to permanent SNS. Of these, only one had good pain control at latest follow-up of 5 years; the remaining two patients obtained no benefit and had their devices removed or deactivated. These two patients both had depression that was also not improved by SNS.

CONCLUSION

This study would suggest that SNS is not an effective treatment for chronic anal pain in the majority of patients. PNE is not an effective means of identifying which of these patients are likely to respond to permanent SNS.

Seven-year experience of enterocutaneous fistula with univariate and multivariate analysis of factors associated with healing: development of a validated scoring system

AIM

The management of enterocutaneous fistulae (ECF) is complex and challenging. We examined factors associated with fistula healing at a National Intestinal Failure Centre and devised the first scoring system to predict spontaneous fistula healing prior to surgery.

METHOD

A retrospective audit of 177 patients (mean age 48.7 years) treated over 7 years was undertaken. Results were compared with a previously reported series from this unit. Univariate and multivariate analyses wete performed on variables to assess relationship with ECF healing. A scoring system was devised and validated on a prospective cohort.

RESULTS

One-hundred and fifty patients underwent surgery between January 2003 and December 2009. The overall healing rate following surgery in the current series was 94.6% (82% in the previous series). Mean delay from previous surgery to the current operation was 1 year (compared with 8 months previously). Thirty-day postfistula resection mortality was 0% (compared with 3.5% previously). Twenty-seven patients underwent medical management alone with overall healing rate of 46.4% (vs 19.9%). Multivariate analysis revealed that comorbidity (P = 0.02), source of referral (P = 0.01) and aetiology (P = 0.006) had associations with healing. Almost all patients with scores of 0 and 1 healed, whereas the highest scores healed least frequently.

CONCLUSION

Surgical management of ECF is safe and improving. Fistula healing is affected by aetiology, comorbidity and source of referral. The scoring system has the potential to predict ECF healing and can be a useful clinical decision-making tool.

A review of posterior tibial nerve stimulation for faecal incontinence

AIM

This review aimed to assess the published results of posterior tibial nerve stimulation (PTNS) for faecal incontinence.

METHOD

A search was performed of PubMed, MEDLINE and Embase to identify studies describing the clinical outcome of PTNS for faecal incontinence.

RESULTS

Thirteen studies were identified. These described the outcome of PTNS for faecal incontinence in 273 patients. Four described transcutaneous PTNS, eight percutaneous PTNS and one compared both methods of PTNS with a sham transcutaneous group. One investigated patients with faecal incontinence and spinal cord injury and another with inflammatory bowel disease. There was marked heterogeneity of the treatment regimens and of the end points used. All reported that PTNS improved faecal incontinence. A > 50% improvement was reported in episodes of faecal incontinence in 63-82% of patients. An improvement was seen in urgency (1-5 min). Improvement was also described in the Cleveland Clinic faecal incontinence score in eight studies. Patients with urge and mixed incontinence appear to benefit more than those with passive incontinence. Treatment regimens ranged in duration from 1-3 months. A residual therapeutic effect is seen after completion of treatment. Follow-up ranged from 1-30 months.

CONCLUSION

PTNS is effective for faecal incontinence. However, many of the published studies are of poor quality. Comparison between studies is difficult owing to differences in the outcome measures used, technique of PTNS and the timing and duration of treatment.

Excessive bone formation in a mouse model of ankylosing spondylitis is associated with decreases in Wnt pathway inhibitors

Introduction

Ankylosing spondylitis (AS) is unique in its pathology where inflammation commences at the entheses before progressing to an osteoproliferative phenotype generating excessive bone formation that can result in joint fusion. The underlying mechanisms of this progression are poorly understood. Recent work has suggested that changes in Wnt signalling, a key bone regulatory pathway, may contribute to joint ankylosis in AS. Using the proteoglycan-induced spondylitis (PGISp) mouse model which displays spondylitis and eventual joint fusion following an initial inflammatory stimulus, we have characterised the structural and molecular changes that underlie disease progression.

Methods

PGISp mice were characterised 12 weeks after initiation of inflammation using histology, immunohistochemistry (IHC) and expression profiling.

Results

Inflammation initiated at the periphery of the intervertebral discs progressing to disc destruction followed by massively excessive cartilage and bone matrix formation, as demonstrated by toluidine blue staining and IHC for collagen type I and osteocalcin, leading to syndesmophyte formation. Expression levels of DKK1 and SOST, Wnt signalling inhibitors highly expressed in joints, were reduced by 49% and 63% respectively in the spine PGISp compared with control mice (P < 0.05) with SOST inhibition confirmed by IHC. Microarray profiling showed genes involved in inflammation and immune-regulation were altered. Further, a number of genes specifically involved in bone regulation including other members of the Wnt pathway were also dysregulated.

Conclusions

This study implicates the Wnt pathway as a likely mediator of the mechanism by which inflammation induces bony ankylosis in spondyloarthritis, raising the potential that therapies targeting this pathway may be effective in preventing this process.

Sacral nerve stimulation for constipation

BACKGROUND

For over 10 years sacral nerve stimulation (SNS) has been used for patients with constipation resistant to conservative treatment. A review of the literature is presented.

METHODS

PubMed, MEDLINE and Embase databases were searched for studies demonstrating the use of SNS for the treatment of constipation.

RESULTS

Thirteen studies have been published describing the results of SNS for chronic constipation. Of these, three were in children and ten in adults. Test stimulation was successful in 42-100 per cent of patients. In those who proceeded to permanent SNS, up to 87 per cent showed an improvement in symptoms at a median follow-up of 28 months. The success of stimulation varied depending on the outcome measure being used. Symptom improvement correlated with improvement in quality of life and patient satisfaction scores.

CONCLUSION

SNS appears to be an effective treatment for constipation, but this needs to be confirmed in larger prospective studies with longer follow-up. Improved outcome measures need to be adopted given the multiple symptoms that constipation may be associated with. Comparison with other established surgical therapies also needs consideration.

Ski overexpression in skeletal muscle modulates genetic programs that control susceptibility to diet-induced obesity and insulin signaling

Transgenic mice overexpressing chicken Ski (c-Ski) have marked decrease in adipose mass with skeletal muscle hypertrophy. Recent evidence indicates a role for c-Ski in lipogenesis and energy expenditure. In the present study, wild type (WT) and c-Ski mice were challenged on a high-fat (HF) diet to determine whether c-Ski mice were resistant to diet-induced obesity. During the HF feeding WT mice gained significantly more weight than chow-fed animals, while c-Ski mice were partially resistant to the effects of the HF diet on weight. Body composition analysis confirmed the decreased adipose mass in c-Ski mice compared to WT mice. c-Ski mice possess a similar metabolic rate and level of food consumption to WT littermates, despite lower activity levels and on chow diet show mild glucose intolerance relative to WT littermates. On HF diet, glucose tolerance surprisingly remained unchanged in c-Ski mice, while it became worse in WT mice. Skeletal muscle of c-Ski mice exhibit impaired insulin-stimulated Akt phosphorylation and glucose uptake. In concordance, gene expression profiling of skeletal muscle of chow and HF-fed mice indicated that Ski suppresses gene expression associated with insulin signaling and glucose uptake and alters gene pathways involved in myogenesis and adipogenesis. In conclusion, c-Ski mice are partially resistant to diet-induced obesity and display aberrant insulin signaling and glucose homeostasis which is associated with alterations in gene expression that inhibit lipogenesis and insulin signaling. These results suggest Ski plays a major role in skeletal muscle metabolism and adipogenesis and hence influences risk of obesity and diabetes.

A mouse with an N-Ethyl-N-nitrosourea (ENU) Induced Trp589Arg Galnt3 mutation represents a model for hyperphosphataemic familial tumoural calcinosis

Mutations of UDP-N-acetyl-alpha-D-galactosamine polypeptide N-acetyl galactosaminyl transferase 3 (GALNT3) result in familial tumoural calcinosis (FTC) and the hyperostosis-hyperphosphataemia syndrome (HHS), which are autosomal recessive disorders characterised by soft-tissue calcification and hyperphosphataemia. To facilitate in vivo studies of these heritable disorders of phosphate homeostasis, we embarked on establishing a mouse model by assessing progeny of mice treated with the chemical mutagen N-ethyl-N-nitrosourea (ENU), and identified a mutant mouse, TCAL, with autosomal recessive inheritance of ectopic calcification, which involved multiple tissues, and hyperphosphataemia; the phenotype was designated TCAL and the locus, Tcal. TCAL males were infertile with loss of Sertoli cells and spermatozoa, and increased testicular apoptosis. Genetic mapping localized Tcal to chromosome 2 (62.64-71.11 Mb) which contained the Galnt3. DNA sequence analysis identified a Galnt3 missense mutation (Trp589Arg) in TCAL mice. Transient transfection of wild-type and mutant Galnt3-enhanced green fluorescent protein (EGFP) constructs in COS-7 cells revealed endoplasmic reticulum retention of the Trp589Arg mutant and Western blot analysis of kidney homogenates demonstrated defective glycosylation of Galnt3 in Tcal/Tcal mice. Tcal/Tcal mice had normal plasma calcium and parathyroid hormone concentrations; decreased alkaline phosphatase activity and intact Fgf23 concentrations; and elevation of circulating 1,25-dihydroxyvitamin D. Quantitative reverse transcriptase-PCR (qRT-PCR) revealed that Tcal/Tcal mice had increased expression of Galnt3 and Fgf23 in bone, but that renal expression of Klotho, 25-hydroxyvitamin D-1α-hydroxylase (Cyp27b1), and the sodium-phosphate co-transporters type-IIa and -IIc was similar to that in wild-type mice. Thus, TCAL mice have the phenotypic features of FTC and HHS, and provide a model for these disorders of phosphate metabolism.

Enrichment of circulating interleukin-17-secreting interleukin-23 receptor-positive γ/δ T cells in patients with active ankylosing spondylitis

OBJECTIVE

Ankylosing spondylitis (AS) is a common inflammatory arthritis affecting primarily the axial skeleton. IL23R is genetically associated with AS. This study was undertaken to investigate and characterize the role of interleukin-23 (IL-23) signaling in AS pathogenesis.

METHODS

The study population consisted of patients with active AS (n = 17), patients with psoriatic arthritis (n = 8), patients with rheumatoid arthritis, (n = 9), and healthy subjects (n = 20). IL-23 receptor (IL-23R) expression in T cells was determined in each subject group, and expression levels were compared.

RESULTS

The proportion of IL-23R-expressing T cells in the periphery was 2-fold higher in AS patients than in healthy controls, specifically driven by a 3-fold increase in IL-23R-positive γ/δ T cells in AS patients. The proportions of CD4+ and CD8+ cells that were positive for IL-17 were unchanged. This increased IL-23R expression on γ/δ T cells was also associated with enhanced IL-17 secretion, with no observable IL-17 production from IL-23R-negative γ/δ T cells in AS patients. Furthermore, γ/δ T cells from AS patients were heavily skewed toward IL-17 production in response to stimulation with IL-23 and/or anti-CD3/CD28.

CONCLUSION

Recently, mouse models have shown IL-17-secreting γ/δ T cells to be pathogenic in infection and autoimmunity. Our data provide the first description of a potentially pathogenic role of these cells in a human autoimmune disease. Since IL-23 is a maturation and growth factor for IL-17-producing cells, increased IL-23R expression may regulate the function of this putative pathogenic γ/δ T cell population.

Macrophage secretory products induce an inflammatory phenotype in hepatocytes

AIM: To investigate the influence of macrophages on hepatocyte phenotype and function.

METHODS: Macrophages were differentiated from THP-1 monocytes via phorbol myristate acetate stimulation and the effects of monocyte or macrophage-conditioned medium on HepG2 mRNA and protein expression determined. The in vivo relevance of these findings was confirmed using liver biopsies from 147 patients with hepatitis C virus (HCV) infection.

RESULTS: Conditioned media from macrophages, but not monocytes, induced a transient morphological change in hepatocytes associated with upregulation of vimentin (7.8 ± 2.5-fold, P = 0.045) and transforming growth factor (TGF)-β1 (2.6 ± 0.2-fold, P < 0.001) and downregulation of epithelial cadherin (1.7 ± 0.02-fold, P = 0.017) mRNA expression. Microarray analysis revealed significant upregulation of lipocalin-2 (17-fold, P < 0.001) and pathways associated with inflammation, and substantial downregulation of pathways related to hepatocyte function. In patients with chronic HCV, real-time polymerase chain reaction and immunohistochemistry confirmed an increase in lipocalin-2 mRNA (F0 1.0 ± 0.3, F1 2.2 ± 0.2, F2 3.0 ± 9.3, F3/4 4.0 ± 0.8, P = 0.003) and protein expression (F1 1.0 ± 0.5, F2 1.3 ± 0.4, F3/4 3.6 ± 0.4, P = 0.014) with increasing liver injury. High performance liquid chromatography-tandem mass spectrometry analysis identified elevated levels of matrix metalloproteinase (MMP)-9 in macrophage-conditioned medium, and a chemical inhibitor of MMP-9 attenuated the change in morphology and mRNA expression of TGF-β1 (2.9 ± 0.2 vs 1.04 ± 0.1, P < 0.001) in macrophage-conditioned media treated HepG2 cells. In patients with chronic HCV infection, hepatic mRNA expression of CD163 (F0 1.0 ± 0.2, F1/2 2.8 ± 0.3, F3/4 5.3 ± 1.0, P = 0.001) and MMP-9 (F0 1.0 ± 0.4, F1/2 2.8 ± 0.3, F3/4 4.1 ± 0.8, P = 0.011) was significantly associated with increasing stage of fibrosis.

CONCLUSION: Secreted macrophage products alter the phenotype and function of hepatocytes, with increased expression of inflammatory mediators, suggesting that hepatocytes actively participate in liver injury.

Electrosurgery ignition of a pneumoperitoneum secondary to prior spontaneous perforation of the small bowel: a cautionary tale

We describe explosive combustion of a gas filled peritoneum from a handheld electrosurgery electrode used to enter the abdomen. The pneumoperitoneum was due to small bowel perforation and peritonitis had been established for at least two days. No injury was caused to either the patient or medical staff. This rare occurrence has only been described once before. Surgeons should be aware of the possible combustion of bowel gas, whether on opening bowel or the peritoneum after bowel perforation.

Interaction between ERAP1 and HLA-B27 in ankylosing spondylitis implicates peptide handling in the mechanism for HLA-B27 in disease susceptibility

Ankylosing spondylitis is a common form of inflammatory arthritis predominantly affecting the spine and pelvis that occurs in approximately 5 out of 1,000 adults of European descent. Here we report the identification of three variants in the RUNX3, LTBR-TNFRSF1A and IL12B regions convincingly associated with ankylosing spondylitis (P < 5 × 10(-8) in the combined discovery and replication datasets) and a further four loci at PTGER4, TBKBP1, ANTXR2 and CARD9 that show strong association across all our datasets (P < 5 × 10(-6) overall, with support in each of the three datasets studied). We also show that polymorphisms of ERAP1, which encodes an endoplasmic reticulum aminopeptidase involved in peptide trimming before HLA class I presentation, only affect ankylosing spondylitis risk in HLA-B27-positive individuals. These findings provide strong evidence that HLA-B27 operates in ankylosing spondylitis through a mechanism involving aberrant processing of antigenic peptides.

Whole blood transcriptional profiling in ankylosing spondylitis identifies novel candidate genes that might contribute to the inflammatory and tissue-destructive disease aspects

INTRODUCTION

A number of genetic-association studies have identified genes contributing to ankylosing spondylitis (AS) susceptibility but such approaches provide little information as to the gene activity changes occurring during the disease process. Transcriptional profiling generates a 'snapshot' of the sampled cells' activity and thus can provide insights into the molecular processes driving the disease process. We undertook a whole-genome microarray approach to identify candidate genes associated with AS and validated these gene-expression changes in a larger sample cohort.

METHODS

A total of 18 active AS patients, classified according to the New York criteria, and 18 gender- and age-matched controls were profiled using Illumina HT-12 whole-genome expression BeadChips which carry cDNAs for 48,000 genes and transcripts. Class comparison analysis identified a number of differentially expressed candidate genes. These candidate genes were then validated in a larger cohort using qPCR-based TaqMan low density arrays (TLDAs).

RESULTS

A total of 239 probes corresponding to 221 genes were identified as being significantly different between patients and controls with a P-value <0.0005 (80% confidence level of false discovery rate). Forty-seven genes were then selected for validation studies, using the TLDAs. Thirteen of these genes were validated in the second patient cohort with 12 downregulated 1.3- to 2-fold and only 1 upregulated (1.6-fold). Among a number of identified genes with well-documented inflammatory roles we also validated genes that might be of great interest to the understanding of AS progression such as SPOCK2 (osteonectin) and EP300, which modulate cartilage and bone metabolism.

CONCLUSIONS

We have validated a gene expression signature for AS from whole blood and identified strong candidate genes that may play roles in both the inflammatory and joint destruction aspects of the disease.

Whole-exome re-sequencing in a family quartet identifies POP1 mutations as the cause of a novel skeletal dysplasia

Recent advances in DNA sequencing have enabled mapping of genes for monogenic traits in families with small pedigrees and even in unrelated cases. We report the identification of disease-causing mutations in a rare, severe, skeletal dysplasia, studying a family of two healthy unrelated parents and two affected children using whole-exome sequencing. The two affected daughters have clinical and radiographic features suggestive of anauxetic dysplasia (OMIM 607095), a rare form of dwarfism caused by mutations of RMRP. However, mutations of RMRP were excluded in this family by direct sequencing. Our studies identified two novel compound heterozygous loss-of-function mutations in POP1, which encodes a core component of the RNase mitochondrial RNA processing (RNase MRP) complex that directly interacts with the RMRP RNA domains that are affected in anauxetic dysplasia. We demonstrate that these mutations impair the integrity and activity of this complex and that they impair cell proliferation, providing likely molecular and cellular mechanisms by which POP1 mutations cause this severe skeletal dysplasia.

Skeletal dysplasias are a group of genetic disorders affecting skeletal development that cause deficiencies and deformities of the limbs and spine, dwarfism, or abnormal bone strength. Skeletal dysplasias are usually inherited as monogenic Mendelian traits or occur as a result of de novo mutations. We report identification of mutations in human POP1 gene as the cause of a severe novel skeletal dysplasia. Molecular analyses presented in our work provide an important link between the pathogenesis of the disease and basic cellular processes including RNA processing and the cell cycle. We posit that our work will also have an immediate impact on assessment and counselling of novel cases of severe short stature.

Association of STAT3 and TNFRSF1A with ankylosing spondylitis in Han Chinese

OBJECTIVES

Recent association studies by the Australo-Anglo-American Spondyloarthritis Consortium (TASC) in Caucasian European populations from Australia, North America and the UK have identified a number of genes as being associated with ankylosing spondylitis (AS). A candidate gene study in a Han Chinese population was performed based on these findings to identify associated genes in this population.

METHODS

A case-control study was performed in a Han Chinese population of patients with AS (n = 775) and controls (n = 1587) from Shanghai and Nanjing. All patients met the modified New York criteria for AS. The cases and controls were genotyped for 115 single nucleotide polymorphisms (SNPs) tagging IL23R, ERAP1, STAT3, JAK2, TNFRSF1A and TRADD, as well as other confirmation SNPs from the TASC study, using the Sequenom iPlex and the ABI OpenArray platforms. Statistical analysis of genotyped SNPs was performed using the Cochran-Armitage test for trend and meta-analysis was performed using METAL. SNPs in AS-associated genes in this study were then imputed using MaCH, and association with AS tested by logistic regression.

RESULTS

SNPs in TNFRSF1A (rs4149577, p = 8.2 × 10⁻⁴), STAT3 (rs2293152, p = 0.0015; rs1053005, p = 0.017) and ERAP1 (rs27038, p = 0.0091; rs27037, p = 0.0092) were significantly associated with AS in Han Chinese. Association was also observed between AS and the intergenic region 2p15 (rs10865331, p = 0.023). The lack of association between AS and IL23R in Han Chinese was confirmed (all SNPs p > 0.1).

CONCLUSIONS

The study results demonstrate for the first time that genetic polymorphisms in STAT3, TNFRSF1A and 2p15 are associated with AS in Han Chinese, suggesting common pathogenic mechanisms for the disease in Chinese and Caucasian European populations. Furthermore, previous findings demonstrating that ERAP1, but not IL23R, is associated with AS in Chinese patients were confirmed.