Alterations of taste perception in Crohn's disease and their dependency on disease activity and nutritional behavior

Altered peripheral taste function in a mouse model of inflammatory bowel disease

Increased sugar intake and taste dysfunction have been reported in patients with inflammatory bowel disease (IBD), a chronic disorder characterized by diarrhea, pain, weight loss and fatigue. It was previously unknown whether taste function changes in mouse models of IBD. Mice consumed dextran sodium sulfate (DSS) during three 7-day cycles to induce chronic colitis. DSS-treated mice displayed signs of disease, including significant weight loss, diarrhea, loss of colon architecture, and inflammation of the colon. After the last DSS cycle we assessed taste function by recording electrophysiological responses from the chorda tympani (CT) nerve, which transmits activity from lingual taste buds to the brain. DSS treatment significantly reduced neural taste responses to natural and artificial sweeteners. Responses to carbohydrate, salt, sour or bitter tastants were unaffected in mice with colitis, but umami responses were modestly elevated. DSS treatment modulated the expression of receptor subunits that transduce sweet and umami stimuli in oral taste buds as a substrate for functional changes. Dysregulated systemic cytokine responses or dysbiosis that occurs during chronic colitis may be upstream from changes in oral taste buds. We demonstrate for the first time that colitis alters taste input to the brain, which could exacerbate malnutrition in IBD patients.

Altered peripheral taste function in a mouse model of inflammatory bowel disease

Increased sugar intake and taste dysfunction have been reported in patients with inflammatory bowel disease (IBD), a chronic disorder characterized by diarrhea, pain, weight loss and fatigue. It was previously unknown whether taste function changes in mouse models of IBD. Mice consumed dextran sodium sulfate (DSS) during three 7-day cycles to induce chronic colitis. DSS-treated mice displayed signs of disease, including significant weight loss, diarrhea, loss of colon architecture, and inflammation of the colon. After the last DSS cycle we assessed taste function by recording electrophysiological responses from the chorda tympani (CT) nerve, which transmits activity from lingual taste buds to the brain. DSS treatment significantly reduced neural taste responses to natural and artificial sweeteners. Responses to carbohydrate, salt, sour or bitter tastants were unaffected in mice with colitis, but umami responses were modestly elevated. DSS treatment modulated the expression of receptor subunits that transduce sweet and umami stimuli in oral taste buds as a substrate for functional changes. Dysregulated systemic cytokine responses, or dysbiosis that occurs during chronic colitis may be upstream from changes in oral taste buds. We demonstrate for the first time that colitis alters taste input to the brain, which could exacerbate malnutrition in IBD patients.

Behavioral and neurophysiological taste responses to sweet and salt are diminished in a model of subclinical intestinal inflammation

There is strong evidence for gut-taste bud interactions that influence taste function, behavior and feeding. However, the effect of gut inflammation on this axis is unknown despite reports of taste changes in gastrointestinal (GI) inflammatory conditions. Lipopolysaccharide (LPS), an inflammatory stimulus derived from gram-negative bacteria, is present in the normal GI tract and levels increase during high-fat feeding and gut infection and inflammation. Recordings from the chorda tympani nerve (CT), which transmits taste information from taste buds on the anterior tongue to the brain, previously revealed a transient decrease in sucrose responses in mice that ingest LPS during a single overnight period. Here we test the effect of acute or chronic, weekly LPS gavage on licking behavior and CT responses. Using brief-access testing, rats treated with acute LPS and mice receiving acute or chronic LPS decreased licking responses to sucrose and saccharin and to NaCl in mice. In long-term (23 h) tests chronic LPS also reduced licking responses to saccharin, sucrose, and NaCl in mice. Neurophysiological recordings from the CT supported behavioral changes, demonstrating reduced responses to sucrose, saccharin, acesulfame potassium, glucose and NaCl in acute and chronic LPS groups compared to controls. Chronic LPS significantly elevated neutrophils in the small intestine and colon, but LPS was not detected in serum and mice did not display sickness behavior or lose weight. These results indicate that sweet and salt taste sensitivity could be reduced even in asymptomatic or mild localized gut inflammatory conditions such as inflammatory bowel disease.

Influence of cancer and acute inflammatory disease on taste perception: a clinical pilot study

Purpose

Cancer patients are at high risk of malnutrition and tumor cachexia further increasing morbidity and mortality. Reasons for cachexia are not clear yet, but inflammatory processes as well as the occurrence of taste disorders reducing nutrient uptake are discussed to play key roles. The purpose of this study was to gain insight into causative factors of taste disturbance in cancer patients. Does the cancer itself, inflammatory processes or cancer therapy influence taste disorders?

Methods

To capture an underlying taste disorder patients with cancer (n = 42), acutely hospitalized inflammatory disease patients (n = 57) and healthy controls (n = 39) were examined. To assess the influence of chemotherapy, patients with and without chemotherapy were compared. Taste tests were performed according to DIN ISO 3972:2011. Inflammation was recorded using laboratory parameters. Statistical evaluation was conducted using the Software R.

Results

Cancer patients showed significantly increased taste thresholds for sweet, salty, and umami compared to healthy controls. There were no significant differences in taste detection and recognition between patients with former, current, or without chemotherapeutical treatment. Patients with an acute inflammatory disease showed an increased taste threshold for umami compared to healthy controls.

Conclusions

It could be shown that cancer patients suffer from taste disorders irrespective of an existing chemotherapeutical treatment. Cancer-related inflammation appears to have a greater impact on taste perception than an acute inflammatory process. Therefore, an adapted dietary adjustment should be carried out at an early stage for cancer patients in order to avoid nutritional disorders caused by a taste disorder.

Oral pathology in inflammatory bowel disease

The incidence of inflammatory bowel diseases (IBD) - Crohn’s disease (CD) and ulcerative colitis (UC) - has been increasing on a global scale, and progressively, more gastroenterologists will be included in the diagnosis and treatment of IBD. Although IBD primarily affects the intestinal tract, extraintestinal manifestations of the disease are often apparent, including in the oral cavity, especially in CD. Specific oral manifestations in patients with CD are as follows: indurate mucosal tags, cobblestoning and mucogingivitis, deep linear ulcerations and lip swelling with vertical fissures. The most common non-specific manifestations, such as aphthous stomatitis and angular cheilitis, occur in both diseases, while pyostomatitis vegetans is more pronounced in patients with UC. Non-specific lesions in the oral cavity can also be the result of malnutrition and drugs. Malnutrition, followed by anemia and mineral and vitamin deficiency, affects the oral cavity and teeth. Furthermore, all of the drug classes that are applied to the treatment of inflammatory bowel diseases can lead to alterations in the oral cavity due to the direct toxic effects of the drugs on oral tissues, as well as indirect immunosuppressive effects with a risk of developing opportunistic infections or bone marrow suppression. There is a higher occurrence of malignant diseases in patients with IBD, which is related to the disease itself and to the IBD-related therapy with a possible oral pathology. Treatment of oral lesions includes treatment of the alterations in the oral cavity according to the etiology together with treatment of the primary intestinal disease, which requires adequate knowledge and a strong cooperation between gastroenterologists and specialists in oral medicine.

Review article: non-malignant oral manifestations in inflammatory bowel diseases

BACKGROUND

Patients with inflammatory bowel diseases (IBD) may present with lesions in their oral cavity. Lesions may be associated with the disease itself representing an extraintestinal manifestation, with nutritional deficiencies or with complications from therapy.

AIM

To review and describe the spectrum of oral nonmalignant manifestations in patients with inflammatory bowel diseases [ulcerative colitis (UC), Crohn's disease (CD)] and to critically review all relevant data.

METHODS

A literature search using the terms and variants of all nonmalignant oral manifestations of inflammatory bowel diseases (UC, CD) was performed in November 2014 within Pubmed, Embase and Scopus and restricted to human studies.

RESULTS

Oral lesions in IBD can be divided into three categories: (i) lesions highly specific for IBD, (ii) lesions highly suspicious of IBD and (iii) nonspecific lesions. Oral lesions are more common in CD compared to UC, and more prevalent in children. In adult CD patients, the prevalence rate of oral lesions is higher in CD patients with proximal gastrointestinal tract and/or perianal involvement, and estimated to range between 20% and 50%. Oral lesions can also occur in UC, with aphthous ulcers being the most frequent type. Oral manifestations in paediatric UC may be present in up to one-third of patients and are usually nonspecific.

CONCLUSIONS

Oral manifestations in IBD can be a diagnostic challenge. Treatment generally involves managing the underlying intestinal disease. In cases presenting with local disabling symptoms and impaired quality of life, local and systemic medical therapy must be considered and/or oral surgery may be required.

Subjective and objective olfactory abnormalities in Crohn's disease

The pathogenesis of Crohn's disease (CD) is still unknown, but the involvement of the olfactory system in CD appears possible. No study to date has systematically assessed the olfactory function in CD patients. We investigated the olfactory function in CD patients in active (n = 31) and inactive disease (n = 27) and in a control group of age- and sex-matched healthy subjects (n = 35). Subjective olfactory testing was applied using the Sniffin' Sticks test. For olfactory testing, olfactory event-related potentials (OERPs) were obtained with a 4-channel olfactometer using phenyl ethyl alcohol (PEA) and hydrogen sulfide (H(2)S). Carbon dioxide (CO(2)) was employed as control stimulus, and chemosomatosensory event-related potentials (CSSERPs) were registered. Results of the Sniffin' Sticks test revealed significantly different olfactory hedonic judgment with increased olfactory hedonic estimates for pleasant odorants in CD patients in active disease compared with healthy subjects. A statistical trend was found toward lower olfactory thresholds in CD patients. In objective olfactory testing, CD patients showed lower amplitudes of OERPs and CSSERPs. Additionally, OERPs showed significantly shorter N1- and P2 latencies following stimulation of the right nostril with H(2)S in CD patients in inactive disease compared with controls. Our study demonstrates specific abnormalities of olfactory perception in CD patients.

Smell and taste in inflammatory bowel disease

Objective

To investigate the olfactory/gustatory functions of patients with inflammatory bowel disease (IBD) by smell/taste tests, and to determine if disease activity or medication might influence the olfactory/gustatory functions of patients.

Patients and Methods

In total, 59 IBD patients (37 Crohn's disease (CD) and 22 ulcerative colitis (UC) patients) were studied using “Sniffin' sticks” and “taste strips” for olfactory and gustatory tests, respectively, and compared to healthy controls and published normative data.

Results

Among IBD (CD and UC) patients, the values for odor threshold, but not for odor identification or discrimination, were significantly lower than that of the normative data. Further, these patients showed lower values than the normative taste values and the control group for all tastes, except sour; 57.6% of the IBD patients were hyposmic, while 30.5% were hypogeusic. Subjective self-assessments showed that the patients were not aware of their reduced olfactory/gustatory functions. There were no relevant differences in taste and smell abilities between the CD and UC patients. Disease activity and treatment did not influence the olfactory/gustatory functions.

Conclusion

IBD (CD and UC) patients exhibited significant reductions in the olfactory and gustatory functions. Therefore, patients should be tested by smell/taste tests, in order to be adequately informed of their olfactory/gustatory functions and provided an understanding of how to overcome their limitations, and thus improve their quality of life.