Personality characteristics and medical impact of stimulant laxative abuse in eating disorder patients-a pilot study

BACKGROUND

Stimulant laxative abuse as a purging behavior can be profound in those with eating disorders. However, the psychopathology leading to stimulant laxative abuse is poorly understood. Furthermore, the medical impact of stimulant laxative abuse has not been studied in this population.

METHODS

Six individuals abusing stimulant laxatives underwent a barium enema to assess for evidence of the cathartic colon syndrome and 29 individuals engaging in any purging behaviors completed the Tri-dimensional Personality Questionnaire-Short Form, Sensitivity to Punishment/Sensitivity to Reward Questionnaire-Short Form, Beck Depression Inventory, and the State Trait Anxiety Inventory questionnaires.

RESULTS

Three of the six patients completing the barium enema had the radiographic findings consistent with cathartic colon. Individuals engaging in laxative abuse showed higher Novelty Seeking compared to those engaging in other forms of purging, and those engaging in any form of purging behavior showed greater Sensitivity to Punishment compared to Sensitivity to Reward. There was also the presence of greater Harm Avoidance than Reward Dependence in this population.

CONCLUSION

There may be different psychopathology that contributes to the abuse of stimulant laxatives than that associated with other forms of purging. Regardless of the driving factor, further research is warranted to discover best therapeutic interventions given the potential to develop the cathartic colon syndrome with ongoing use of stimulant laxatives. Cathartic colon is a condition whereby the colon, or lower intestine, is converted into an inert tube incapable of propagating fecal matter. It is thought to develop due to over-use of stimulant laxatives. However, it is unclear if this condition truly exists and whether it contributes to the constipation experienced by individuals with eating disorders who have extensive past histories of abusing laxatives. It is also unclear if laxative abuse presents with different medical complications than other forms of purging. The purpose of this study is to determine whether radiographic evidence of cathartic colon can be found in eating disorder patients abusing stimulant laxatives, whether there are different medical complications with laxative abuse versus other forms of purging, and to examine the psychological composition of individuals who engage in severe laxative abuse. Specifically, the authors investigated the interrelationship between Harm Avoidance and Reward Dependence, with emphasis on gaining a better understanding of Reward Dependence by examining both Sensitivity to Reward and Sensitivity to Punishment in patients who engage in severe laxative abuse. Our findings suggest that stimulant laxative abuse may cause the development of cathartic colon changes and that there may be unique psychopathology that contributes to the abuse of stimulant laxatives. Given the higher Novelty Seeking personality-dimension in those abusing laxatives, it is possible that this purging behavior may be considered addiction-like in nature, which would have distinct treatment implications.

Animal models of cathartic colon

The incidence of cathartic colon has been increasing, but satisfactory treatments are still lacking. In order to study the pathological mechanisms of the disorder and identify effective treatment methods, researchers have established different animal models of cathartic colon. This minireview briefly summarizes several common cathartic colon animal models, induced with anthraquinone laxatives such as rhubarb, total anthraquinone, rhein, and emodin, or induced with diphenylmethane laxatives such as phenolphthalein. The advantages and limitations of these models are evaluated and analyzed. We hope that this review will facilitate the selection of suitable models and improve relevant modeling methods. We anticipate the development of more convenient and stable models that can reflect the characteristics of cathartic colon in humans, and serve as useful tools for further studies.

Mechanism of aqueous fructus aurantii immaturus extracts in neuroplexus of cathartic colons

AIM

To examine the effect of aqueous fructus aurantii immaturus (FAI) extracts on the intestinal plexus of cathartic colons.

METHODS

Cathartic colons were induced in rats with dahuang, a laxative used in traditional Chinese medicine. Once the model was established (after approximately 12 wk), rats were administered mosapride (1.54 mg/kg) or various doses of aqueous FAI extracts (1-4 g/kg) for 14 d. Transit function was assessed using an ink propulsion test. Rats were then sacrificed, and the ultramicrostructure of colonic tissue was examined using transmission electron microscopy. The expression of the 5-hydroxytryptamine receptor 4 (5-HTR4) and neurofilament-H was assessed in colon tissues using real-time PCR, Western blot, and immunohistochemistry.

RESULTS

Mosapride and high dose (4 g/kg) of aqueous FAI extracts significantly improved the bowel movement in cathartic colons compared to untreated model colons as measured by the intestinal transit rate (70.06 ± 7.25 and 72.02 ± 8.74, respectively, vs 64.12 ± 5.19; P < 0.05 for both). Compared to controls, the ultramicrostructure of cathartic colons showed signs of neural degeneration. Treatment with mosapride and aqueous FAI extracts resulted in recovery of ultrastructural pathology. Treatment with mosapride alone upregulated the gene and protein expression of 5-HTR4 compared to untreated controls (P < 0.05 for both). Treatment with aqueous FAI extracts (≥ 2 g/kg) increased 5-HTR4 mRNA levels (P < 0.05), but no change in protein level was observed by Western blot or immunohistochemistry. The mRNA and protein levels of neurofilament-H were significantly increased with mosapride and ≥ 2 g/kg aqueous FAI extracts compared to controls (P < 0.05 for all).

CONCLUSION

Aqueous FAI extracts and mosapride strengthen bowel movement in cathartic colons via increasing the expression of 5-HTR4 and neurofilament-H.

Effect of Atractylodes macrocephala Koidz and Rehmannia dride rhizome on gastrointestinal motility in rats with cathartic colon

AIM: To observe the influence of Atractylodes macrocephala Koidz and Rehmannia dride rhizome on gastrointestinal motility in a rat model which was given rhein suspension to induce cathartic colon.

METHODS: Seventy healthy male Wistar rats were randomly divided into seven groups: a control group, a model group, a conventional dose Atractylodes macrocephala Koidz group, a high-dose Atractylodes macrocephala Koidz group, a Rehmannia dride rhizome group, a conventional dose Atractylodes macrocephala Koidz+Rehmannia dride rhizome group, and a high-dose Atractylodes macrocephala Koidz+Rehmannia dride rhizome group, with ten rats in each group. Rhein suspension was administered to induce cathartic colon. After successful modelling, the control and model groups were given normal saline by gavage, and the rest groups were given corresponding drug(s), respectively. All rats were killed after 14 d. The gastric motility and intestinal transit function were examined.

RESULTS: Carbon black transit rate (%) in the model group was significantly lower compared with the blank control group (39.24 ± 4.28 vs 61.84 ± 3.05, P < 0.05), while gastric residual rate (%) increased significantly (72.74 ± 8.94 vs 36.30 ± 9.57, P < 0.05). Compared with the model group, each treatment significantly reduced the gastric residual rate (%) (57.90 ± 8.57, 45.65 ± 9.31, 41.75 ± 9.16, 45.05 ± 8.52, 38.10 ± 9.79 vs 72.74 ± 8.94, P < 0.05) and increased the carbon black transit rate (%) (49.10 ± 3.06, 56.76 ± 5.16, 52.13 ± 4.37, 53.72 ± 4.29, 60.96 ± 2.51 vs 39.24 ± 4.28, P < 0.05). The gastric residual rate (%) was lower and carbon black transit rate (%) was higher in the high-dose Atractylodes macrocephala Koidz group, conventional dose Atractylodes macrocephala Koidz group, conventional dose Atractylodes macrocephala Koidz+Rehmannia dride rhizome group, and high-dose Atractylodes macrocephala Koidz+Rehmannia dride rhizome group than in the Rehmannia dride rhizome group (45.65 ± 9.31, 41.75 ± 9.16, 45.05 ± 8.52, 38.10 ± 9.79 vs 57.90 ± 8.57, P < 0.05; 56.76 ± 5.16, 52.13 ± 4.37, 53.72 ± 4.29 vs 49.10 ± 3.06, P < 0.05), with the difference in carbon black transit rate (%) was most significant in the high-dose Atractylodes macrocephala Koidz+Rehmannia dride rhizome group (60.96 ± 2.51 vs 49.10 ± 3.06, 56.76 ± 5.16, 52.13 ± 4.37, 53.72 ± 4.29, P < 0.05).

CONCLUSION: Atractylodes macrocephala Koidz and Rehmannia dride rhizome can promote the gastrointestinal motility, with high-dose Atractylodes macrocephala having a better effect. High-dose Atractylodes macrocephala Koidz+Rehmannia dride rhizome has the most significant effect on gastrointestinal motility.

Comparison of rat models of cathartic colon established with rhein and rhubarb

AIM: To find a simple and stable drug for the induction of cathartic colon by comparing two rat models which were established with rhein and rhubarb, respectively.

METHODS: Thirty-three healthy 3-4-week-old Wistar rats were divided into three groups, namely, a control group, a rhubarb group and a rhein group. Normal saline was given by intragastric administration in the control group. Rhubarb suspension was given in the rhubarb group, and rhein suspension was given in the rhein group. The intestinal transit function was assessed using the activated carbon suspension transit method.

RESULTS: Modeling time was 136 and 114 d for the rhubarb group and rhein group, respectively. Activated carbon transit length in the rhubarb and rhein group was significantly shorter than that in the control group. The symptom of loose stools in the rhein group was stable in the modeling process, and the dose and modeling cycle were consistent with the reference literature.

CONCLUSION: A rat model of cathartic colon could be successfully established with both rhubarb and rhein. As a monomer, the efficacy of rhein is more stable than rhubarb. Concentration of rhein is easy to control and it is associated with a relatively short period of time in establishing the animal model. Rhein is better than rhubarb in establishing the rat model of cathartic colon.

Role of SCF/c-Kit signaling pathway in the pathogenesis of cathartic colon

AIM: To investigate the role of SCF/c-Kit signaling pathway in the pathogenesis of cathartic colon.

METHODS: Thirty-six healthy adult SD rats were randomly divided into three groups (12 rats per group): control group, model group, and recovery group. The control group was given normal saline by gavage, and the model group and recovery group were given rhein suspension by gavage to induce cathartic colon. Specimens were taken immediately after modeling in the model group and 30 days after modeling in the recovery group. The intestinal transit function was assessed in each rats of each group by detecting the first melena discharge time. RT-PCR and Western blot were used to detect SCF/c-Kit mRNA and protein expression levels in colon tissue.

RESULTS: Compared to the control group, the first melena discharge time was significantly prolonged in the model group (491.5 ± 40.2 vs 373.4 ± 46.5, P < 0.01); however, there was no significant difference in the first melena discharge time between the model group and recovery group (477.9 ± 39.6 vs 491.5 ± 40.2, P > 0.05). Compared to the control group, c-Kit and SCF mRNA and protein expression levels were significantly decreased in both the model group and recovery group (all P < 0.01); however, there were no significant differences in c-Kit and SCF mRNA and protein expression levels between the model group and recovery group (both P > 0.05).

CONCLUSION: Reduced colonic motility in rats with cathartic colon may be associated with down-regulation of SCF/c-Kit signaling in colon tissue.