Probiotics and prebiotics in Crohn's disease therapies

Best Practice & Research Clinical Gastroenterology 30 (2016) 81e88

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Best Practice & Research Clinical Gastroenterology

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Probiotics and prebiotics in Crohn's disease therapies Lev Lichtenstein, MD a, b, *, Irit Avni-Biron, MD a, b, Ofer Ben-Bassat, MD a, b a b

Rabin Medical Center, Petah Tikva, Israel Sackler Faculty of Medicine, University of Tel Aviv, Israel

a b s t r a c t Keywords: Probiotics Prebiotics Synbiotics Inflammatory bowel disease Crohn's disease VSL#3 Sacchromyces boullardi Bifidobacterium Lactobacillus

Therapeutic manipulation of gut microbiota has proven valuable in the management of ulcerative colitis and pouchitis. Despite some similarities among the various inflammatory bowel conditions, the probiotics investigated thus far seem to confer little benefit in Crohn's disease. In this review, we aim to bring together the evidence available on the clinical effect of probiotics and prebioltics in Crohn's disease patients, and to clarify the place of probiotic treatment in current Crohn's therapeutic regimens. © 2016 Elsevier Ltd. All rights reserved.

Introduction A variety of in vitro experiments and animal models show that probiotic strains could reshape gut immune parameters [1e4]. Correlation of these findings with physiological events taking place within the human body, however, is far from unequivocal [5]. Results from controlled clinical trials are not always consistent with preclinical findings, especially in the immunologically diverse field of inflammatory bowel disease: for example, though probiotics have proven to be fairly advantageous in pouchitis and UC, those investigated thus far seem to confer little benefit in Crohn's disease. In this review, we aim to clarify the evidence available on the clinical effect of probiotics and prebiotics in current therapeutic regimens for Crohn's disease. In doing so, we take into consideration different treatment endpoints (induction of remission vs. prevention of relapses), anatomical nuances

* Corresponding author. Gastroenterology Institute, Rabin Medical Center, Derech Jabotinsky 39 Petah Tikva 4941492, Israel. E-mail address: [email protected] (L. Lichtenstein). http://dx.doi.org/10.1016/j.bpg.2016.02.002 1521-6918/© 2016 Elsevier Ltd. All rights reserved.

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L. Lichtenstein et al. / Best Practice & Research Clinical Gastroenterology 30 (2016) 81e88

(ileal vs. colonic disease), choice of specific microorganism(s), dosages, modes of administration, and duration of therapy. Induction of clinical remission Four relatively small studies [6e9] examined the use of probiotics as an adjunct therapy to conventional treatments, in the induction of clinical remission in Crohn's patients (Table 1). In a pioneering study by Plein and Hotz in 1993 [6], 20 Crohn's patients treated conventionally, yet with some residual diarrhea (bowel movements 5.0 ± 1.4 evacuations/day) and moderate complaints (CDAI 193 ± 32), were also administered the yeast preparation Saccharomyces boulardii for two weeks. A modest yet statistically significant reduction in the frequency of bowel movements (5.0 ± 1.4 vs. 4.1 ± 2.3 evacuations/day; p < 0.01) and in CDAI (193 ± 32 vs. 168 ± 59; p < 0.05) was reported in the open-labeled, uncontrolled induction phase of the study. In a small (4 patients) open-label uncontrolled pilot by Gupta et al. [10], a lactic acid-producing Lactobacillus rhamnosus GG (previously known as L. acidophilus GG) administered for 6 months was observed to ameliorate clinical activity in children with mildly to moderately active Crohn's disease. These results were challenged by a subsequent study by Schultz et al. [7], where 11 adult patients with active Crohn's disease were treated with a combination of corticosteroids (60 mg/day) and antibiotics, and then randomized for addition of LGG or placebo to the treatment regimen. No difference in clinical remission rates was observed during the 6 month-long treatment period. Steed et al. [8] randomized 35 patients with active Crohn's disease to receive a synbiotic regimen comprising Bifidobacterium longum, oligofructose and inulin, or placebo, for 6 months, in tandem with stable doses of conventional medications. Almost half of the patients from both experimental and control arms were lost to follow-up. Bearing in mind this limitation, significant clinical improvement in the rest of the synbiotic group was reported, a finding supported by simultaneous improvement in their histological scores, and reductions in serum levels of pro-inflammatory TNF-a. In addition to those randomized controlled studies, Fujimori et al. [9] reported results from a small open-label, uncontrolled trial involving 10 active and steroid-refractory Crohn's patients treated with psyllium (plantago ovata), and a probiotic preparation consisting of Bifidobacterium breve, Bifidobacterium longum, and Lactobacillus casei. Over the 13 months of synbiotic therapy, 7 out of 10 patients reported symptomatic improvement. However, only 2 of them were able to discontinue corticosteroid treatment, and laboratory markers of inflammation did not improve. Overall, there is no convincing evidence that probiotics e either alone, or in combination with prebiotic preparations e display a significant ability to effectively augment conventional treatments in inducing clinical remission in Crohn's patients [11e15]. Maintenance of medically induced remission Nine studies examined the ability of various probiotic regimens to support the maintenance of medically induced clinical remission in such patients [6,7,16e22] (Table 2).

Table 1 Use of probiotics to induce clinical remission in Crohn's patients. Study

No. of patients

Duration (months)

Probiotic strain

Control

Outcome

Plein, 1993 [6] 17

½ month

S. boulardii

Schultz et al., 2004 [7] Steed et al., 2010 [8] Fujimori et al., 2007 [9]

11

6

LGG þ Corticosteroids

Open-labeled; Modest symptomatic uncontrolled improvement Placebo þ Corticosteroids No benefit

35 (16 lost to follow- up) 10

6

B. longum þ “Synergy 1”

Placebo

13

B. longum, B. breve, L. casei þ Plantago ovata

Open-labeled; uncontrolled

Symptomatic improvement Symptomatic improvement


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Table 2 Use of probiotics to maintain medically induced remission in Crohn's patients. Study

No. of patients

Duration (months)

Probiotic strain

Control

Outcome

Plein, 1993 [6] Guslandi et al., 2000 [16] Bourreille et al., 2013 [17]

17 35 165

3 6 12

S. boulardii

Placebo Pentasa Placebo

Malchow et al., 1997 [18] Willert et al., 2010 [19] (Abstract) Schultz et al., 2004 [7] Zocco et al., 2003 [20] (Abstract) Bousvaros et al., 2005 [21] Rutgeerts et al., [22] (Abstract)

28 Colonic 30 colonic

12 12

E. coli Nissle VSL#3

Placebo Placebo

Improvement Prevented relapses No benefit overall; favorable in nonsmokers? No benefit Deterioration (NS)

11 35

6 12

LGG

Placebo No benefit Mesalamine No benefit

75 pediatric 42 63 6

“Synbiotic 2000”

Inulin Placebo

Deterioration (NS) No benefit

Three trials explored the effect of the probiotic yeast Saccharomyces boulardii on the maintenance of medically induced remission [6,16,17]. Unlike all the other studies concerning maintenance of medically induced remission, the results of these trials were not uniformly negative. In the aforementioned study by Plein and Hotz in 1993 [6], 17 patients e still with some residual activity after the initial open-labeled induction phase (CDAI 168 ± 59) e were randomized to continue receiving either S. boulardii or placebo for an additional 10 weeks. While the probiotic group continued to experience a gradual reduction in the frequency of bowel movements (from 4.1 ± 2.3 to 3.3 ± 1.2 evacuations per day) and in CDAI scores (from 168 ± 59 to 107 ± 85), in the control group, both parameters eventually returned to their pre-treatment range. In a trial by Guslandi et al. in 2000 [16], 32 patients in steroid-free remission were randomized to receive 6 months of maintenance treatment with either Pentasa, or a combination of Pentasa and S. boulardii. Clinical relapse was reported in 6.25% of patients maintained on the probioticemesalamine combination, compared to a 37.5% relapse rate in patients maintained on mesalamine alone (p ¼ 0.04). Lastly, and in the largest study undertaken so far, Bourreille et al. in 2013 [17] randomly assigned 165 patients brought into remission with steroids, to continue treatment with either S. boulardii or placebo for 52 weeks. The probiotic regimen did not yield a meaningful effect in the entire study population: 47.5% of patients treated with S. boulardii relapsed during the study period, compared to a 53.2% relapse rate in the placebo arm. However, a post hoc analysis indicated that S. boulardii may exert some favorable preventive effect in non-smokers. Two other studies concerned the effect of probiotics on predominantly colonic Crohn's disease [18,19]. In 1997, Malchow et al. [18] reported data from 28 such Crohn's patients. All were enrolled in the trial during the active phase of their disease, treated with prednisolone (60 mg/day) for induction of remission, then randomized to receive maintenance therapy with either E. coli Nissle 1917, or a placebo. The probiotic did not prove to be superior to placebo in maintaining remission in this 12-month-long, randomized double blind trial. In a 2010 study whose results were published as an abstract, Willert et al. [19] randomized 30 patients with predominantly colonic Crohn's disease in steroid-free remission to receive either VSL#3 or placebo for 12 months, both alongside the patient's standard maintenance therapy. VSL#3 was not effective in maintaining remission in those patients, and was even associated with a greater percentage of flares (8 of 14 patients who received VSL#3, vs. 1 of 9 who received placebo; p ¼ 0.04). Three other studies explored the effectiveness of Lactobacillus rhamnosus GG in maintaining medically induced remission [7,20,21]. In the aforementioned study by Schultz et al. in 2004 [7], patients brought into remission by corticosteroids, with or without LGG, continued to receive either LGG or placebo as maintenance therapy. No difference in clinical remission rates was observed, after six months of the treatment.

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In another study, whose findings were published as an abstract in 2003, Zocco et al. [20] reported outcomes in 35 patients with quiescent Crohn's disease, randomized to receive either LGG, mesalamine, or a combination of both. After 12 months of such treatment, the groups did not differ with respect to clinical symptoms (CDAI) or endoscopic features. In a multi-center trial whose results were summarized by Bousvaros et al. in 2005 [21], 75 children with quiescent Crohn's disease were randomized to receive LGG plus inulin, or inulin alone, in addition to their pre-enrollment maintenance regimen. Addition of LGG showed no preventive benefit, and may even have led to some deterioration (a relapse rate of 31%, vs. 17% in those receiving inulin alone; p ¼ 0.18). As a consequence, the study was prematurely stopped after 42 months. In a study published as an abstract in 2004, Rutgeerts et al. [22] reported outcomes of 63 patients with active Crohn's disease who received on-demand infusions with 5 mg/kg IV infliximab and were randomized to treatment with a complex synbiotic preparation Synbiotic 2000 (comprised of Pediacoccus pentoseceus, Lactobacillus raffinolactis, Lactobacillus paracasei susp paracasei 19, Lactobacillus plantarum, b-glucans, inulin, pectin, and resistant starch) or to placebo. The patients were followed until clinical relapse occurred. By the end of this 6 months long trial, the intervention and the placebo groups did not differ in terms of time to relapse or median interval between demanded infliximab infusions. Several attempts to combine and re-analyze the data collected in the aforementioned studies also resulted in negative conclusions [13e15,23e25]. Overall, with the possible exception of Saccharomyces boulardii in certain populations (e.g., non-smokers), long-term treatment by probiotic microorganisms seems to yield no benefit in maintaining remission in patients with either colonic or ileo-colonic luminal Crohn's disease. Prevention of post-operative recurrence Six studies aimed to determine the efficacy of probiotic strains in maintaining surgically induced remission in Crohn's patients [26e31] (Table 3). The main strength of those studies lies in the fact that most were uniformly designed, and included meticulous endoscopic assessment reported by means of Rutgeerts scores. In a single-blind study published by Campieri et al. as an abstract in 2000 [26], forty post-operative patients were randomized to receive the complex probiotic preparation VSL#3 (following pretreatment with the non-absorbable wide-spectrum antibiotic rifaximin for 3 months), or mesalamine. Compared with placebo, the sequential antibiotic-probiotic therapy was associated with a significantly lower incidence of severe endoscopic recurrence, both at 3 months (10% vs. 40%; p < 0.01) and at 12 months (20% vs. 40%; p < 0.01). Table 3 Use of probiotics to prevent post-operative recurrence in Crohn's patients. Study

No. of Duration Probiotic patients (months) strain

Outcome

12

Rifaximin eVSL#3

Mesalamine Lower incidence of endoscopic recurrence

12

VSL#3

Placebo

45

12

LGG

Placebo

98

6

L. johnsonii Placebo

No benefit

70

3

Placebo

No benefit

30

24

“Synbiotic Placebo 2000”

No benefit

40 Campieri et al., 2000 [26] (abstract) Fedorak et al., 2015 120 [27]

Prantera et al., 2002 [28] Marteau et al., 2006 [29] Van Gossum et al., 2007 [30] Chermesh et al., 2007 [31]

Control

No statistically significant benefit short-term (underpowered). Lower incidence of severe endoscopic recurrence longterm if started immediately post-surgery (NS) Deterioration (NS)


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A recent Canadian multi-center randomized, placebo-controlled trial (Fedorak et al., 2015 [27]) involved large number of study participants (n ¼ 120) yet came underpowered due to the lower than anticipated endoscopic recurrence rate. The results suggested that VSL#3 may exert some modest protective effect in terms of severe early (day 90) endoscopic recurrence (9.3% vs. 17.5%), however, the difference failed to reach statistical significance. In accordance with this observed trend, mucosal pro-inflammatory cytokine expression was significantly lower in the VSL#3 group at day 90 (p < 0.05). Interestingly, the results also suggested that VLS# may exert 12-months protective benefit in patients who started the treatment immediately after surgery, as compared to those who commenced it after 3 months' treatment with placebo (10% vs. 26.7%, p ¼ 0.09). Four other studies yielded less enthusiastic conclusions [28e31]: In 2002, Prantera et al. [28] randomized 45 patients to receive either LGG or placebo for 12 months following ileo-cecal resection. Clinical recurrence was reported in 16.6% of the LGG group, as compared to 10.5% in the placebo group. In patients in clinical remission, endoscopic recurrence was noted in 60% of patients in the LGG group, as compared to 35.3% of those receiving placebo (p ¼ 0.297). No significant differences in the severity of the lesions were observed. Studies by Marteau of GETAID in 2006 [29] (98 patients; followed for 6 months) and by Van Gossum's group in the Netherlands in 2007 [30] (70 patients; followed for 3 months) failed to show any advantage to use of the probiotic Lactobacillus johnsonii, in terms of clinical or endoscopic recurrence. An Israeli multi-center group led by Chermesh et al. [31] (30 patients; followed over 24 months) came to a similar negative conclusion over an aforementioned synbiotic preparation Synbiotic 2000. Several attempts to combine and re-analyze the data concerning the ability of probiotics to prevent clinical or endoscopic post-operative recurrence of Crohn's disease were not convincing [13,32e34].

Prebiotics in Crohn's disease Prebiotics are functional fibers that may selectively stimulate the growth of beneficial gut microbiota, and are fermented to short chain fatty acids. Scant evidence exists regarding their use in Crohn's disease. In 2007, Hafer et al. [35] randomized 17 patients with active Crohn's disease to receive lactulose (10 g daily) or placebo. No significant improvements in clinical activity index, endoscopic score, or immunohistochemical parameters were observed during the 4 month-long study period; in fact, the group given placebo responded better. In a small, open-label trial by Lindsay et al., 2006 [36], 10 patients with active ileocolonic Crohn's were administered 15 g of fructo-oligosaccharides (inulin) for 3 weeks, with some promising results. Likewise, Joossens et al., 2011 [37] reported a modest yet statistically significant clinical improvement in a small subgroup of patients (n ¼ 8) that entered this 4-week long microbiological outcome study when having mildly to moderately active Crohn's disease. However, when the same prebiotic was subjected to a well powered (n ¼ 103), placebo-controlled trial by Benjamin et al., 2011 [38], it was proven to be of no clinical benefit.

Conclusions A quick search of Pubmed for the MESH terms “probiotic” and “Crohn's disease” reveals 15 original intervention trials published as full articles, a relative paucity of experimental studies compared to 9 meta-analyses of their data, and over 100 opinion-based reviews. This discrepancy underscores the great enthusiasm and high expectations of clinicians for therapeutic manipulation of the gut microbiota, and an intestinal immune response by means of “beneficial microorganisms.” Unfortunately, neither the experimental studies themselves, nor the meta-analyses of their findings, are thus far able to live up to these expectations.

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Probiotics investigated so far confer little benefit in inducing clinical remission in Crohn's patients. With the possible exception of Saccharomyces boulardii in certain populations (e.g., non-smokers), long-term treatment by probiotic microorganisms shows no benefit in maintaining medically achieved remission in patients with either colonic or ileo-colonic luminal Crohn's disease. Data thus far concerning the ability of probiotics to prevent post-operative clinical or endoscopic recurrence of Crohn's disease are not convincing. However, the trends observed in some experiments with VSL#3, and the observation that Saccharomyces boulardii could be more successful than other probiotic agents in maintaining medically achieved remission, may serve as a rationale for carrying out additional studies aimed at exploring the preventive effects of post-operative alteration of the intestinal microflora.

Practice points No evidence presently exists that would support the use of probiotics to induce clinical remission in Crohn's patients. With the possible exception of Saccharomyces boulardii in certain populations (e.g., nonsmokers), probiotics show no benefit in maintaining medically achieved remission in patients with either colonic or ileo-colonic luminal Crohn's disease. There is no clear evidence to support the use of probiotics to prevent post-operative recurrence of Crohn's disease; however, some related questions remain unanswered, and more research is required in this field.

Research agenda Thus far, attempts to manipulate the gut microbiota in inflammatory bowel disease were fairly empiric, and failed to explain the striking differences between their observed effects on ulcerative colitis, pouchitis, and Crohn's disease. As we progress in our understanding of the mechanisms by which the individual agents influence and reshape the gut immune system, more precisely designed, mechanism-based experiments are expected in the future. Observations that in certain populations, Saccharomyces boulardii could be successful in maintaining medically achieved remission may warrant additional experimental clarification. Trends suggesting that VSL#3 started within 30 days post-surgery may exert a preventive effect on post-operative recurrence of Crohn's disease, call for additional studies along these lines.

Conflict of interest statement The authors declare no conflict of interest.

Authors' contributions Lev Lichtenstein, Irit Avni-Biron and Ofer Ben Bassat conducted literature searches, and contributed to the study design, data collection, data analysis, data interpretation, writing and revising the


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manuscript, and table creation. All authors had full access to all of the study data, reviewed it, and take final responsibility for the decision to submit their findings for publication. Funding No specific funding supported this work.

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