Review article: the therapy of constipation

Constipation is a common symptom that may be idiopathic or due to various identifiable disease processes. Laxatives are agents that add bulk to intestinal contents, that retain water within the bowel lumen by virtue of osmotic effects, or that stimulate intestinal secretion or motility, thereby increasing the frequency and ease of defecation. Drugs which improve constipation by stimulating gastrointestinal motility by direct actions on the enteric nervous system are under development. Other modalities used to treat constipation include biofeedback and surgery. Laxatives and lavage solutions are also used for colon preparation and evacuation of the bowels after toxic ingestions.     

Review article: self-report measures to evaluate constipation

Background Constipation is a subjective phenomenon, and as such must be evaluated using patient self‐report. Valid and reliable measures of constipation are essential to standardize the diagnosis, assess the severity and evaluate the effectiveness of treatments. Aim To compare and contrast published self‐report measures of constipation in terms of development, content, general characteristics, psychometric properties and clinical utility. Methods MEDLINE (1966–2007), CINAHL (1980–2007), Cochrane (1993–2007) and Web of Science (1995–2007) were searched to identify self‐report measures of constipation. Measures of constipation were selected if they: (i) were self‐report measures that measured only constipation; (ii) had undergone psychometric testing; (iii) were used in adults and (iv) were written in English. Results Seven self‐report measures of constipation were identified. The content areas evaluated by these measures varied. Only two measures had adequate validity and reliability, sensitivity to change, or were tested in more than one sample. Conclusions Findings from this review suggest that the Chinese Constipation Questionnaire and the Patient Assessment of Constipation‐Symptom Questionnaire demonstrate adequate psychometric properties for a constipation measure. Additional research is warranted to refine or develop a more comprehensive self‐report measure to evaluate constipation in adults.     

Review article: oral ulcers and its relevance to systemic disorders

Oral ulceration is a common problem, and is sometimes a marker of gastroenterological disease. Patients with signs or symptoms of oral ulcers are sometimes referred to gastroenterology clinics, however, in most instances the ulcers does not reflect gastrointestinal disease. Indeed, a spectrum of disorders other than those of the gut can give rise to oral mucosal ulcers ranging from minor local trauma to significant local disease such as malignancy or systemic illness. This present article reviews aspects of the aetiology, diagnosis and management of common ulcerative disorders of the oral mucosa.     

Review article: Chronic constipation and food hypersensitivity--an intriguing relationship

BACKGROUND: Chronic constipation is common in the general population. Some studies have shown that in children cow's milk protein hypersensitivity can cause chronic constipation unresponsive to laxative treatment. AIMS: To review the literature and summarize the data that point to a relationship between refractory chronic constipation and food hypersensitivity, and to discuss the hypothesis that the pathogenesis of constipation due to food hypersensitivity. METHODS: A search in the U.S. National Library of Medicine was performed, matching the key words 'chronic constipation, food intolerance and allergy'. RESULTS: Thirty-three papers were found but only 19 of them were related to the topic of this review. Most of the data indicated a relationship between constipation and food allergy in a subgroup of paediatric patients with 'idiopathic' constipation unresponsive to laxative treatment. There was only one study in adults that demonstrated the resolution of chronic constipation on hypoallergenic diet in four patients. CONCLUSIONS: An increasing number of reports suggest a relationship between refractory chronic constipation and food allergy in children. Similar data in adults are scarce and need to be confirmed. Further studies should be performed to obtain firmer evidence for the role of allergy in constipation and clarify the pathogenetic mechanisms involved.     

Review article: bloating in functional bowel disorders

Bloating is a frequently reported symptom in functional bowel disorders. It usually occurs in combination with other symptoms, but may also occur in isolation. The severity of bloating tends to worsen during the course of the day and improves overnight. Although frequently considered to be a subjective phenomenon, recent studies have shown that bloating is associated with a measurable increase in abdominal girth. The pathophysiology of bloating remains elusive, but the evidence supports a sensorimotor dysfunction of the bowel. The possible mechanisms include abnormal gas trapping, fluid retention, food intolerance and altered gut microbial flora. Further studies are needed to define the sensorimotor abnormalities associated with bloating, which might be segmental and transient rather than generalized and persistent. The lack of understanding of this symptom is paralleled by a limited availability of therapeutic options. Conventional medications used in functional bowel disorders are not helpful and may indeed worsen the symptoms. In future, new drugs with activity against serotonin and kappa receptors, or novel approaches such as the use of exclusion diets, probiotics and hypnotherapy, may prove to be useful.     

Review article: gender-related differences in functional gastrointestinal disorders

Many functional gastrointestinal disorders and other chronic visceral pain disorders such as interstitial cystitis and chronic pelvic pain are more common in women than in men. In irritable bowel syndrome (IBS) there is a 2 : 1 female to male ratio in prevalence of symptoms in community samples. Female irritable bowel syndrome patients are more likely to be constipated, complain of abdominal distension and of certain extracolonic symptoms.
While animal studies have clearly demonstrated gender-related differences in pain perception and antinociceptive mechanisms, unequivocal evidence for gender-related differences in human pain perception or modulation has only been provided recently. Gender-related differences may be related to constant differences in the physiology of pain perception, such as structural or functional differences in the visceral afferent pathways involved in pain transmission or modulation, and/or they may be related to fluctuations in female sex hormones.
Preliminary evidence suggests that female irritable bowel syndrome patients show specific perceptual alterations in regards to rectosigmoid balloon distension and that they show differences in regional brain activation measured by positron emission tomography. This preliminary evidence suggests that gender-related differences in symptoms and in the perceptual responses to visceral stimuli exist in IBS patients and can be detected using specific stimulation paradigms and neuroimaging techniques.     

Review article: the role of butyrate on colonic function

Background  Butyrate, a short-chain fatty acid, is a main end-product of intestinal microbial fermentation of mainly dietary fibre. Butyrate is an important energy source for intestinal epithelial cells and plays a role in the maintenance of colonic homeostasis.
Aim  To provide an overview on the present knowledge of the bioactivity of butyrate, emphasizing effects and possible mechanisms of action in relation to human colonic function.
Methods  A PubMed search was performed to select relevant publications using the search terms: 'butyrate, short-chain fatty acid, fibre, colon, inflammation, carcinogenesis, barrier, oxidative stress, permeability and satiety'.
Results  Butyrate exerts potent effects on a variety of colonic mucosal functions such as inhibition of inflammation and carcinogenesis, reinforcing various components of the colonic defence barrier and decreasing oxidative stress. In addition, butyrate may promote satiety. Two important mechanisms include the inhibition of nuclear factor kappa B activation and histone deacetylation. However, the observed effects of butyrate largely depend on concentrations and models used and human data are still limited.
Conclusion  Although most studies point towards beneficial effects of butyrate, more human in vivo studies are needed to contribute to our current understanding of butyrate-mediated effects on colonic function in health and disease.     

Review article: the current and evolving treatment of colonic diverticular disease

Background  Formation of colonic diverticula, via herniation of the colonic wall, is responsible for the development of diverticulosis and consequently diverticular disease. Diverticular disease can be associated with numerous debilitating abdominal and gastrointestinal symptoms (including pain, bloating, nausea, constipation and diarrhoea).
Aims  To review the state of treatment for diverticular disease and its complications, and briefly discuss potential future therapies.
Methods  PubMed and recent conference abstracts were searched for articles describing the treatment of diverticular disease.
Results  Many physicians will recommend alterations to lifestyle and increasing fibre consumption. Empirical antibiotics remain the mainstay of therapy for patients with diverticular disease and rifaximin seems to be the best choice. In severe or relapsing disease, surgical intervention is often the only remaining treatment option. Although novel treatment options are yet to become available, the addition of therapies based on mesalazine (mesalamine) and probiotics may enhance treatment efficacy.
Conclusions  Data suggest that diverticular disease may share many of the hallmarks of other, better-characterized inflammatory bowel diseases; however, treatment options for patients with diverticular disease are scarce, revolving around antibiotic treatment and surgery. There is a need for a better understanding of the fundamental mechanisms of diverticular disease to design treatment regimens accordingly.     

Review article: pancreatic renin-angiotensin systems in health and disease

Aliment Pharmacol Ther 2011; 34: 840–852

Summary

Background In addition to the circulating (endocrine) renin–angiotensin system (RAS), local renin–angiotensin systems are now known to exist in diverse cells and tissues. Amongst these, pancreatic renin–angiotensin systems have recently been identified and may play roles in the physiological regulation of pancreatic function, as well as being implicated in the pathogenesis of pancreatic diseases including diabetes, pancreatitis and pancreatic cancer. Aim To review and summarise current knowledge of pancreatic renin–angiotensin systems. Methods We performed an extensive PubMed, Medline and online review of all relevant literature. Results Pancreatic RAS appear to play various roles in the regulation of pancreatic physiology and pathophysiology. Ang II may play a role in the development of pancreatic ductal adenocarcinoma, via stimulation of angiogenesis and prevention of chemotherapy toxicity, as well as in the initiation and propagation of acute pancreatitis (AP); whereas, RAS antagonism is capable of preventing new‐onset diabetes and improving glycaemic control in diabetic patients. Current evidence for the roles of pancreatic RAS is largely based upon cell and animal models, whilst definitive evidence from human studies remains lacking. Conclusions The therapeutic potential for RAS antagonism, using cheap and widely available agents, and may be untapped and such roles are worthy of active investigation in diverse pancreatic disease states.     

Review article: the management of pelvic floor disorders

Anorectal disorders, such as faecal incontinence, defecation difficulty and conditions associated with anorectal pain, are commonly encountered in the practices of gastroenterologists, urogynaecologists and colorectal surgeons. The evaluation of these disorders has been very much improved by the development and wider availability of diagnostic tests, such as manometry, endo-anal ultrasound, static and dynamic pelvic magnetic resonance imaging and electromyography. After briefly reviewing the normal anatomy and physiology of the anorectum, the pathophysiology and diagnostic approaches to faecal incontinence, defecation disorders and functional anorectal pain are discussed. Until recently, the management of these disorders has been largely anecdotal. However, our therapeutic armamentarium has been expanded by pharmacological agents, such as nitrates, calcium channel blockers and botulinum toxin, as well as the development of novel techniques, such as sacral nerve stimulation. These and other pharmacological, behavioural and surgical approaches are reviewed with respect to the robustness of evidence to support their efficacy in patients with these disorders.     

Review article: olestra and its gastrointestinal safety

Olestra is a fat substitute made from sucrose and vegetable oil. Olestra is neither digested nor absorbed, and therefore adds no calories or fat to the diet. Because the gut is the only organ that is exposed to olestra, the potential for olestra to affect gastrointestinal structure and function, and the absorption of nutrients from the gut, has been investigated. Histological evaluations performed after long-term feeding studies have shown no indications that olestra causes injury to the gastrointestinal mucosa. Olestra is not metabolized by the colonic microflora, and has no meaningful effects on the metabolic function of these organisms. Studies of gastrointestinal transit have shown that the consumption of olestra with food does not affect gastric emptying, or small or large bowel transit times. Olestra does not affect the absorption of macronutrients, water-soluble vitamins or minerals. It causes a dose-responsive decrease in the availability of the fat-soluble vitamins A, D, E and K; however, this potentially adverse effect is offset by the addition of vitamins to olestra-containing foods. Olestra has no consistent effect on the amount of total bile acids excreted in the faeces, and therefore probably has no significant effect on bile acid absorption. The occurrence of gastrointestinal symptoms, including diarrhoea, loose stools, gas and abdominal cramping, after consumption of olestra under ordinary snacking conditions is comparable to that following consumption of triglyceride-containing snacks.