Intact vitreous humor as a potential extracellular matrix hydrogel for cartilage tissue engineering applications.

Decellularisation of tissues, utilising their biochemical cues, poses exciting tissue engineering (TE) opportunities. However, removing DNA from cartilage (dCart) requires harsh treatments due to its dense structure, causing loss of bioactivity and limiting its application as a cartilaginous extra cellular matrix (ECM). In this study, we demonstrate for the first time the successful application of vitreous humor (VH), a highly hydrated tissue closely resembling the glycosaminoglycan (GAG) and collagen composition of cartilage, as an ECM hydrogel to support chondrogenic differentiation. Equine VH was extracted followed by biochemical quantifications, histological examinations, cytotoxicity (human mesenchymal stromal cells, hMSCs and human articular chondrocytes, hACs) and U937 cell proliferation studies. VH was further seeded with hACs or hMSCs and cultured for 3-weeks to study chondrogenesis compared to scaffold-free micro-tissue pellet cultures and collagen-I hydrogels. Viability, metabolic activity, GAG and DNA content, chondrogenic gene expression (aggrecan, collagen I/II mRNA) and mechanical properties were quantified and matrix deposition was visualised using immunohistochemistry (Safranin-O, collagen I/II). VH was successfully extracted, exhibiting negligible amounts of DNA (0.4 ±â€¯0.4 µg/mg dry-weight) and notable preservation of ECM components. VH displayed neither cytotoxic responses nor proliferation of macrophage-like U937 cells, instead enhancing both hMSC and hAC proliferation. Interestingly, encapsulated cells self-assembled the VH-hydrogel into spheroids, resulting in uniform distribution of both GAGs and collagen type II with increased compressive mechanical properties, rendering VH a permissive native ECM source to fabricate cartilaginous hydrogels for potential TE applications. STATEMENT OF SIGNIFICANCE: Fabricating bioactive and cell-instructive cartilage extracellular matrix (ECM) derived biomaterials and hydrogels has over recent years proven to be a challenging task, often limited by poor retention of inherent environmental cues post decellularisation due to the dense and avascular nature of native cartilage. In this study, we present an alternative route to fabricate highly permissive and bioactive ECM hydrogels from vitreous humor (VH) tissue. This paper specifically reports the discovery of optimal VH extraction protocols and cell seeding strategy enabling fabrication of cartilaginous matrix components into a hydrogel support material for promoting chondrogenic differentiation. The work showcases a naturally intact and unmodified hydrogel design that improves cellular responses and may help guide the development of cell instructive and stimuli responsive hybrid biomaterials in a number of TERM applications.

Abnormal small bowel motility in patients with hereditary transthyretin amyloidosis.

BACKGROUND: Gastrointestinal complications are common in hereditary transthyretin amyloid (ATTRm) amyloidosis. The underlying mechanisms have not been fully elucidated, and the patients' small bowel function remains largely unexplored. The aim of the present study was to compare the small bowel motility in ATTRm amyloidosis patients with that in non-amyloidosis patient controls. METHODS: ATTRm amyloidosis patients undergoing evaluation for liver transplantation were consecutively investigated with 24-hour duodenojejunal manometry (n = 19). The somatostatin analogue octreotide was used to induce fasting motility. Patients with age at onset of ≥50 years were defined as late-onset cases. For each patient, three age- and sex-matched patient controls (n = 57) were selected from the total pool of investigated patients. KEY RESULTS: Manometry was judged as abnormal in 58% of the patients and in 26% of the patient controls (P = .01). Patients displayed significantly more daytime phase III migrating motor complexes than patient controls (median 4 vs 2, P < .01), and had a higher frequency of low-amplitude complexes (16% vs 4%; however, this difference did not reach statistical significance, P = .10). Furthermore, late-onset patients showed a delay in octreotide response (5.4 vs 3.8 minutes, P < .01), but this was not observed for early-onset patients or within the control group. CONCLUSIONS AND INFERENCES: Patients with ATTRm amyloidosis displayed abnormalities in their small bowel motility more frequently than non-amyloidosis patient controls, and the manometric pattern was probably best consistent with a combined neuromyopathic disorder. The delayed octreotide response in late-onset patients warrants further investigation.

Validation of SmartPill® wireless motility capsule for gastrointestinal transit time: Intra-subject variability, software accuracy and comparison with video capsule endoscopy.

BACKGROUND: There is interest in ultimately combining endoscopy and motility assessments. Gastric emptying (GET), small bowel (SBTT), colon (CTT) and whole gut transit (WGTT) times are conveniently obtained by SmartPill® wireless motility capsule (WMC) that records luminal pH, temperature and pressure. Reproducibility within same subjects and accuracy of software derived times (MotiliGI® ) were investigated for diagnostic application. GET and SBTT were separately measured using video capsule endoscopy (VCE). The aim of this investigation was to assess same subject reproducibility of WMC, accuracy of software derived transit times and relate to Pillcam® SB (small bowel) VCE motility data. METHODS: Seventy three healthy adults ingested a 260 kcal mixed meal followed by WMC tests. Food intake was permitted after 6 hours. Regional transit data was obtained for GET, SBTT and CTT, the sum yielding WGTT. Nineteen subjects repeated WMC tests 2 or 4 weeks later; a separate 70 underwent VCE while fasted. KEY RESULTS: Visually derived data from WMC yielded GET 3.46±0.27, SBTT 5.15±0.21, CTT 20.76±1.19 and WGTT 29.53±1.28 hours (mean±SEM). Pearson's correlation coefficients (r) against software derived results were: GET 0.78 (P<.0001), SBTT 0.28 (P<.05), CTT 0.96 (P<.0001), WGTT 0.99 (P<.0001). VCE yielded lower GET (0.71±0.08 hours) and SBTT (4.15±0.13 hours). CONCLUSIONS AND INFERENCES: GET, SBTT, CTT and WGTT obtained by WMC are commensurate with literature values, including by other methods. Visually and software derived transit times have strongest correlations for CTT and WGTT. WMC yields longer GET and SBTT than VCE, perhaps due to meal related effects on motility.

Increased serum levels of lipopolysaccharide and antiflagellin antibodies in patients with diarrhea-predominant irritable bowel syndrome.

BACKGROUND: Innate immune responses to conserved microbial products such as lipopolysaccharide (LPS) and flagellin are likely important in microbial-host interactions and intestinal homeostasis. We hypothesized that bacterial translocation and activation of mucosal immunity against common microbial antigens might be involved in the development of irritable bowel syndrome (IBS). We therefore compared serum levels of LPS, soluble CD14 (sCD14), and flagellin antibodies between patients with different subtypes of IBS and healthy controls. METHODS: We analyzed serum obtained from 88 patients (74 females) aged 19(43)-73 years and 106 healthy volunteers (77 females) aged 19(38)-62 years. Diarrhea-predominant IBS (D-IBS) was present in 32 patients (36%), 23 patients (26%) had constipation-predominant IBS (C-IBS), and 33 patients (38%) had A-IBS. We used ELISA for sCD14 and antiflagellin immunoglobulin G and limulus amebocyte assay for LPS. Abdominal symptoms and psychiatric comorbidities were assessed using validated questionnaires. KEY RESULTS: We found a significantly higher serum level of LPS in patients with D-IBS compared to controls (p = 0.0155). The level of antibodies to flagellin was higher in patients with IBS than in controls (mainly driven by higher levels in D-IBS, p = 0.0018). The levels of sCD14 were lower in D-IBS patients compared to controls (p = 0.0498). We found a weak, but significant correlation between the levels of antiflagellin antibodies and anxiety among IBS patients (ρ = 0.38; p = 0.0045). CONCLUSIONS & INFERENCES: Our results support the concept that immune reactivity to luminal antigens may have a role in the development of D-IBS. The serum level of antiflagellin antibodies was found to correlate with patients' self-reported anxiety score.

High-resolution manometry changes our views of gastrointestinal motility.

High-resolution manometry using catheters with 36 solid-state sensors spaced 1 cm apart has already become an established technique for esophageal manometry where it has replaced water-perfused and station pull-through manometry. Spatiotemporal plots with color coding of pressure have greatly facilitated the analysis of esophageal peristalsis. Although suitable for the length of the esophagus, the solid-state catheter is insufficient for the study of longer segments of the gastrointestinal tract. A new technique with fiber-optic sensors has made it possible to construct catheters with 72-144 sensors. Studies of colonic motility have revealed that the most common motor pattern of the colon is a peristaltic contraction that travels 7-10 cm in the retrograde direction. Earlier studies using low-resolution manometry with 7-45 cm between sensors led us to erroneous conclusions regarding direction and frequency of contractions and they largely missed both antegrade and retrograde contractions traveling short distances. Fiber-optic high-resolution manometry holds promise for greatly improving our understanding of gut motor physiology and hopefully also our understanding of patients with symptoms of disordered gut motility.

Infection of human enteroendocrine cells with Chlamydia trachomatis: a possible model for pathogenesis in irritable bowel syndrome.

BACKGROUND: Irritable bowel syndrome (IBS) is a widespread gastrointestinal disorder of unknown etiology. Recently, our group detected chlamydial antigens in enteroendocrine cells (EEC) of jejunum biopsies from patients with IBS. Impairment of EEC secretion upon Chlamydia infection might lead to disturbances of gut functions. We have therefore studied the interaction between Chlamydia and EEC in vitro. METHODS: Two different human enteroendocrine cell lines were studied: LCC-18 from a neuroendocrine colonic tumour and CNDT2 from a small intestinal carcinoid. Cell lines were infected with C. trachomatis serovar LGV II strain 434. We used Penicillin G for inducing persistent infection. The ultrastructure of infected cells was studied using transmission electron microscopy and immunofluorescence and we used RT-PCR analysis for studying changes in gene expression at different stages of infection. KEY RESULTS: We found that both cell lines could be infected with C. trachomatis yielding productive infections and persistence could be induced using penicillin G. Immunofluorescence showed different cellular distributions of serotonin and chromogranin A in non-infected (cytoplasmatic distribution) compared with infected cells (serotonin and chromogranin mostly in chlamydial inclusions). In line with the microscopical findings, we found a significant down-regulation of the gene coding for the vesicular monoamine transporter (VMAT1) in infected compared with non-infected EEC (P<0.05). CONCLUSIONS & INFERENCES: Altered protein distributions together with down-regulation of VMAT1 suggest that chlamydial infection may influence vesicular transport. It is therefore possible that such an infection in vivo could lead to disturbances in the regulation of gut functions.

Can sulphonylurea addition to lifestyle changes help to delay diabetes development in subjects with impaired fasting glucose? The Nepi ANtidiabetes StudY (NANSY).

The Nepi ANtidiabetes StudY (NANSY) is a 5-year randomized, double-blind, placebo-controlled trial in Swedish primary care, examining whether the development of type 2 diabetes (T2D) and retinopathy (separately reported) would be delayed in 40- to 70-year-old subjects with impaired fasting glucose (IFG) who, in addition to lifestyle changes, were treated with either placebo or low-dosage sulphonylurea (SU) (1-mg glimepiride; Amaryl). Of 274 subjects (163 men, 111 women), 138 were allocated to placebo (46.0% men, 56.8% women) and 136 to glimepiride (54.0% men, 43.2% women). The primary endpoint was conversion to diabetes. Average follow-up time was 3.71 years; 96 subjects converted to diabetes, 55 allocated to placebo and 41 to glimepiride (absolute difference 9.8%; p = 0.072). In conclusion, the study failed to support the notion that low-dose SU added to lifestyle changes in IFG subjects would help to delay the conversion to diabetes.

Quantitation of cellular components of the enteric nervous system in the normal human gastrointestinal tract--report on behalf of the Gastro 2009 International Working Group.

BACKGROUND: Patients with gastrointestinal neuromuscular diseases may undergo operative procedures that yield tissue appropriate to diagnosis of underlying neuromuscular pathology. Critical to accurate diagnosis is the determination of limits of normality based on the study of control human tissues. Although robust diagnostic criteria exist for many qualitative alterations in the neuromuscular apparatus, these do not include quantitative values due to lack of adequate control data. PURPOSE: The aim of this report was to summarize all relevant available published quantitative data for elements of the human enteric nervous system (neuronal cell bodies, glial cells, and nerve fibers) from the perspective of the practicing pathologist. Forty studies meeting inclusion criteria were systematically reviewed with data tabulated in detail and discussed in the context of methodological variations and limitations. The results reveal a lack of concordance between observations of different investigators resulting in data insufficient to produce robust normal ranges. This diversity highlights the need to standardize the way pathologists collect, process, and quantitate neuronal and glial elements in enteric neuropathologic samples, as suggested by recent international guidelines on gastrointestinal neuromuscular pathology.

Full-thickness biopsy findings in chronic intestinal pseudo-obstruction and enteric dysmotility.

BACKGROUND AND AIMS: Small bowel manometry is increasingly used in the clinical investigation of patients with symptoms of intestinal motor dysfunction. Enteric dysmotility (ED) has been suggested as a new diagnostic term for patients with abnormal intestinal motor activity but no radiological signs of chronic intestinal pseudo-obstruction (CIP). Histopathological features of adult patients with ED and CIP have been compared in a large case series to study differences and similarities between the two diagnostic groups. METHODS: Routine staining and an extensive panel of immunohistochemical stains on transversal and tangential cuts from full-thickness biopsies of the small bowel were used. RESULTS: 39 females and 11 males with CIP and 58 females and 7 males with ED were investigated. The underlying lesion was more often a visceral myopathy (22% vs 5%) or neuromyopathy (30% vs 12%) in patients with CIP than in those with ED, whereas the predominant lesion in ED was neuropathy with inflammation. CONCLUSION: CIP in adults is associated with very different underlying pathology, whereas ED is more homogeneously associated with neuropathy in the enteric nervous system. Neuropathy of enteric ganglia with inflammation seems to be the most common cause for measurable disturbances of intestinal motor function.

Effects of glucagon infusions on protein and amino acid composition of milk from dairy cows.

Changing the composition of milk proteins and AA affects the nutritional and physical properties of dairy products. Intravenous infusions of glucagon decreases milk protein production and concentration by promoting the use of gluconeogenic blood AA for hepatic glucose synthesis. Little is known about how the diversion of AA to gluconeogenesis affects the composition of milk proteins and AA. The objective was to quantify changes in composition of milk protein and AA in response to i.v. glucagon infusions. Three separate experiments were used: 1) 8 Holstein cows were fed ad libitum and infused with glucagon at 10 mg/d for 14 d, 2) 7 Holstein cows were feed restricted and infused with glucagon at 10 mg/d for 14 d, and 3) 4 Brown Swiss cows were infused with glucagon at 5 and 10 mg/d for 2 d each. Milk and milk component yields and milk protein and amino acid composition of samples, collected with blood samples at the first and last day of the glucagon infusion period, were compared with those collected 1 d before and after the glucagon infusion period. Glucagon infusions decreased milk protein production and concentration in each experiment by at least 0.2 +/- 0.05 kg/d and 4 +/- 0.4 g/L, respectively. The decrease was accompanied by changes in milk protein composition, the most consistent being an increase in kappa-casein (1.68 +/- 0.27%). Overall, glucagon infusions resulted in higher proportions of kappa-casein and alpha(S2)-casein (1.34 +/- 0.51%) and smaller proportions of alpha(S1)-casein (-3.83 +/- 1.75%) and alpha-lactalbumin (-0.91 +/- 0.32%). Glucagon had little impact on milk AA composition except an increase in glycine (0.26 +/- 0.11%). The results suggest that milk protein synthesis is regulated by many factors including AA and glucose availability.

Effects of lipid supplementation on the yield and composition of milk from cows with different beta-lactoglobulin phenotypes.

Responses to lipid supplementation differ between dairy breeds and genetic lines suggesting nutrition by genotype interactions. beta-Lactoglobulin phenotype is associated with changes in yield and composition of milk. The response of cows with different beta-lactoglobulin phenotypes to lipid supplementation has not been examined. Furthermore, we examined whether lipid supplementation alters milk protein composition. By using a randomized block design, we fed Holstein cows for 3 wk either a control diet containing 2.8% crude fat (n = 19) or an experimental diet that was supplemented with 4.2% tallow (n = 20). Before randomization, all cows were fed the supplemental tallow diet for at least 2 wk. Dry matter intake, body weight, milk yield, and milk composition were measured in the last week before and during the experimental period. Feeding supplemental tallow increased dry matter intake and yields of milk and milk components, including casein content, without decreasing milk component content or altering milk protein composition. On the low-fat control diet, cows with the beta-lactoglobulin allele B had a greater milk and milk component yield than cows with the A allele, whereas no differences by beta-lactoglobulin phenotype were observed in cows on the tallow supplement diet. Our results suggest that cows that differ in beta-lactoglobulin phenotype respond differently to a low-fat diet and that feeding cows 4.2% of additional tallow increases milk yield without affecting milk component content and milk protein composition.

Effects of fentanyl on gastric myoelectrical activity: a possible association with polymorphisms of the mu-opioid receptor gene?

BACKGROUND: Opioids have inhibitory effects on gastric motility, but the mechanism is far from clear. Electrical slow waves in the stomach determine the frequency and the peristaltic nature of gastric contractions. The primary aim of this study was to investigate the effects of the opioid fentanyl on gastric myoelectric activity. As there were large variations between the subjects, we investigated whether the variation was correlated to single nucleotide polymorphisms (SNP) of the mu-opioid receptor (MOR) gene. METHODS: We used cutaneous multichannel electrogastrography (EGG) to study myoelectrical activity in 20 patients scheduled for elective surgery. Fasting EGG was recorded for 30 min, followed by intravenous administration of fentanyl 1 microg/kg and subsequent EGG recording for 30 min. Spectral analysis of the two recording periods was performed and the variables assessed were dominant frequency (DF) of the EGG and its power (DP). Genetic analysis of the SNP A118G and G691C of the MOR gene was performed with the polymerase chain reaction technique. RESULTS: There was a significant reduction in DF and DP after intravenous fentanyl. However, there was a large variation between the patients. In eight subjects EGG was unaffected, five subjects had a slower DF (bradygastria) and in six subjects the slow waves disappeared. We found no correlation between the EGG outcome and the presence of A118G or G691C in the MOR gene. CONCLUSIONS: Fentanyl inhibited gastric myoelectrical activity in about half of the subjects. The variation could not be explained by SNP in the MOR gene. Because of small sample size, the results must be regarded as preliminary observations.

Safety and diagnostic yield of laparoscopically assisted full-thickness bowel biospy.

Advances in minimally invasive surgery have made laparoscopy and full-thickness bowel biopsy possible in the investigation of patients with suspected gastrointestinal neuromuscular disorders. The safety and diagnostic yield of this investigation have not been formally reported. A prospective study was undertaken of 124 patients with clinico-physiological diagnoses of chronic intestinal pseudo-obstruction, enteric dysmotility and severe irritable bowel syndrome undergoing LFTB in three European teaching centres with expertise in the management of gastrointestinal neuromuscular disorders. Perioperative data were collected including complications. Diagnostic yield was expressed as proportion with well-established specific neuromuscular abnormalities based on a protocol of routine and immunohistochemical techniques. The majority of patients underwent a laparoscopically assisted procedure with extracorporeal biopsy. Median operating time was 50 min, conversion rate 2% and length of stay 1 day. There was an 8% readmission rate for obstructive symptoms but minimal other morbidity and no mortality. Overall specific diagnostic yield was 81%, being high for jejunal biopsies (89%) but low for a small number of ileal and colonic biopsies. Laparoscopy and full-thickness biopsy of the bowel appears acceptable in terms of safety. It should be performed in a jejunal site to achieve a high diagnostic yield.

Short communication: estimates of genetic variation of milk fatty acids in US Holstein cows.

Interest in changing the milk fatty acid profile is growing. However, little is known about the genetic variability of milk fatty acids in the US Holstein population. Therefore, genetic parameters for milk fatty acids were estimated using a single-trait, mixed, linear animal model on 592 individual milk samples from 233 daughters of 53 sires in a cow herd genetically representative of the US Holstein population. Heritability (h(2)) and repeatability (r) estimates +/- standard errors for yields of individual fatty acids ranged from 0.00 +/- 0.08 (C4:0) to 0.43 +/- 0.13 (C12:0) for heritabilities and from 0.21 +/- 0.05 (C18:1) to 0.43 +/- 0.05 (C12:0) for repeatabilities. Saturated (h(2) = 0.23 +/- 0.12; r = 0.36 +/- 0.05) and de novo synthesized fatty acids (C6:0 to C14:0; h(2) = 0.30 +/- 0.13; r = 0.40 +/- 0.05) had numerically higher estimates than did monounsaturated (h(2) = 0.09 +/- 0.09; r = 0.22 +/- 0.05) and polyunsaturated fatty acids (h(2) = 0.08 +/- 0.09; r = 0.27 +/- 0.05). For relative proportions of individual fatty acids, the greatest heritability and repeatability estimates were obtained for C8:0 (h(2) = 0.18 +/- 0.12; r = 0.36 +/- 0.05), C10:0 (h(2) = 0.22 +/- 0.13; r = 0.46 +/- 0.05), C12:0 (h(2) = 0.18 +/- 0.12; r = 0.46 +/- 0.05), C16:0 (h(2) = 0.09 +/- 0.12; r = 0.48 +/- 0.05), C16:1 (h(2) = 0.49 +/- 0.13; r = 0.49 +/- 0.05), and C18:0 (h(2) = 0.24 +/- 0.11; r = 0.39 +/- 0.05). Our results suggest the existence of genetic variability of milk fatty acids, in particular of medium-and long-chain fatty acids (C8:0 to C18:0), which could be used to improve the nutritional and textural properties of milk fat by selective breeding.

Short communication: Composition of milk protein and milk fatty acids is stable for cows differing in genetic merit for milk production.

Changing the composition of milk protein and of milk fatty acids alters nutritional and physical properties of dairy products and their consumer appeal. Genetic selection for milk yield decreases concentrations of milk protein and of milk fat. Little is known, however, about how the decrease affects composition of milk protein and milk fatty acids. The objective of this study was to quantify changes in composition of milk protein and of milk fatty acids in cows differing in genetic merit for milk production. Three measures of genetic merit for milk production were used for each cow: genetic line, parent average predicted transmitting ability (PTA) for milk, and cow milk PTA. Composition of milk protein and milk fatty acids were compared in 448 milk samples from 178 cows representing 2 divergent lines of Holsteins that were bred for high or average PTA for milk and combined milk protein and fat yield. High-line cows (n = 97) produced more milk that contained less fat and had higher proportions of alphaS1-casein in milk protein than did average-line cows (n = 81). We additionally obtained from 233 cows (178 cows representing the 2 genetic lines and 55 cows with ancestors from both genetic lines) the parent average milk PTA and cow milk PTA and compared composition of milk protein and of milk fatty acids in 592 milk samples. Cows whose parent average milk PTA was above or equal to the median of the 233 cows produced more milk that contained less protein and less fat and that tended to have greater proportions of alphaS1-casein in milk protein than cows whose average milk PTA was below the median. Similarly, cows with above or equal median milk PTA of the 233 cows produced more milk that contained less protein and less fat and had greater proportions of alphaS1-casein in milk protein than did cows with below-median milk PTA. Milk fatty acid composition was not consistently different between groups. Therefore, selection for milk yield decreased concentrations of milk protein and milk fat but had little effect on composition of milk protein and milk fatty acids.

Nutritional aspects in patients with functional gastrointestinal disorders and motor dysfunction in the gut. Working team report of the Swedish Motility Group (SMoG).

In reviews regarding the management of patients with functional gastrointestinal disorders and motility disturbances within the gut nutritional aspects and dietary advice is often put forward as being of great importance. However, there are relatively few high-quality, interventional studies in the literature supporting an important role for general dietary advice to improve symptoms in these patients. Nutritional supplementation to patients with malnutrition due to severe dysfunction of the gastrointestinal tract is of course less controversial, even though different views on how this should be performed exist. The content of this article is based on presentations given by the authors during the second meeting of the Swedish Motility Group held in Gothenburg in March 2005, and aims to give an overview on the role of dietary advice and nutritional supplementation to patients with gastrointestinal dysfunction of different severity.

The nocturnal jejunal migrating motor complex: defining normal ranges by study of 51 healthy adult volunteers and meta-analysis.

Interdigestive human small bowel motility is characterized by the migrating motor complex (MMC). The aims of this study were to: (i) establish the normal range of variables of the nocturnal jejunal MMC and (ii) incorporate these data in a subsequent meta-analysis. Eighty-one recordings were performed by prolonged (24 h) ambulatory manometry in 51 subjects in two centres. Quantitative analysis was undertaken of 419 Phase III and 332 Phase II episodes. Adjusted mean values of seven variables were calculated using a mixed-effects model. Meta-analysis of pooled published data to generate a reliable 95% reference range was also performed. Adjusted mean values and confidence intervals are presented for all seven variables. Intrasubject variances were large in comparison with intersubject. Meta-analysis of 19 studies (356 pooled patients) meeting inclusion criteria produced wide reference ranges. At least five such ranges are useful for the detection of abnormality in the individual. This is the largest study of normal volunteers presented to date, with ranges for many variables produced using appropriate statistical methodology. A model for definition of abnormality has been proposed. We recommend that these data may be used by investigators in this field as a complement to other existing indicators of small bowel dysmotility.

Deranged smooth muscle alpha-actin as a biomarker of intestinal pseudo-obstruction: a controlled multinational case series.

BACKGROUND AND AIMS: Chronic idiopathic intestinal pseudo-obstruction (CIIP) is a severe motility disorder associated with significant morbidity. Several histopathological (neuropathic and myopathic) phenotypes have been described but only a single adult with jejunal smooth (circular) muscle alpha-actin deficiency. We present a prospective multinational case series investigating smooth muscle alpha-actin deficiency as a biomarker of this disease. METHODS: A total of 115 fully clinically and physiologically (including prolonged (24 hour) ambulatory jejunal manometry) characterised CIIP patients from three European centres were studied. Immunohistochemical localisation of actins and other cytoskeletal proteins were performed on laparoscopic full thickness jejunal biopsies and compared with adult controls. Distribution of alpha-actin was also characterised in other gut regions and in the developing human alimentary tract. RESULTS: Twenty eight of 115 (24%) CIIP patient biopsies had absent (n = 22) or partial (n = 6) jejunal smooth muscle alpha-actin immunostaining in the circular muscle layer. In contrast, smooth muscle alpha-actin staining was preserved in the longitudinal muscle and in adult jejunal controls (n = 20). Comparative study of other adult alimentary tract regions and fetal small intestine, suggested significant spatial and temporal variations in smooth muscle alpha-actin expression. CONCLUSIONS: The ability to modulate alpha-smooth muscle actin expression, evident in development, is maintained in adult life and may be influenced by disease, rendering it a valuable biomarker even in the absence of other structural abnormalities.