Mucosal concentrations of N-acetyl-5-aminosalicylic acid related to endoscopic activity in ulcerative colitis patients with mesalamine

Downregulation of OATP2B1 by proinflammatory cytokines leads to 5-ASA hyposensitivity in Ulcerative colitis

5-Aminosalicylic acid (5-ASA) is a first-line agent in both remission and maintenance therapy for ulcerative colitis (UC). However, the mucosal concentration of 5-ASA was significantly lower in patients with severe histological inflammation, which further led to a poor response to 5-ASA treatment. Our study aimed to clarify the mechanism of 5-ASA uptake into colonic epithelial cells and to further explore the reason for the decreased colonic mucosal 5-ASA concentration in UC patients. Our results demonstrated that the colonic 5-ASA concentration was notably reduced in DSS-induced colitis mice and inversely correlated with colonic inflammation. 5-ASA was not a substrate of carnitine/organic cation transporter 1/2 (OCTN1/2) or multidrug resistance protein 1 (MDR1), whereas organic anion transporting polypeptide 2B1 (OATP2B1) and sodium-coupled monocarboxylate transporter 1 (SMCT1) mediated the uptake of 5-ASA, with a greater contribution from OATP2B1 than SMCT1. Inhibitors and siRNAs targeting OATP2B1 significantly reduced 5-ASA absorption in colonic cell lines. Moreover, OATP2B1 expression was dramatically downregulated in colon tissues from UC patients and dextran sodium sulfate (DSS)-induced colitis mice, and was also negatively correlated with colonic inflammation. Mechanistically, mixed proinflammatory cytokines downregulated the expression of OATP2B1 in a time- and concentration-dependent manner through the hepatocyte nuclear factor 4 α (HNF4α) pathway. In conclusion, OATP2B1 was the pivotal transporter involved in colonic 5-ASA uptake, which indicated that inducing OATP2B1 expression may be a strategy to promote 5-ASA uptake and further improve the concentration and anti-inflammatory efficacy of 5-ASA in UC.

The colon targeting efficacies of mesalazine medications and their impacts on the gut microbiome

Successful treatment of ulcerative colitis (UC) is highly dependent on several parameters, including dosing regimen and the ability to deliver drugs to the disease site. In this study two strategies for delivering mesalazine (5-aminosalicylic acid, 5-ASA) to the colon were compared in an advanced in vitro model of the human gastrointestinal (GI) tract, the SHIME® system. Herein, a prodrug strategy employing bacteria-mediated drug release (sulfasalazine, Azulfidine®) was evaluated alongside a formulation strategy that utilised pH and bacteria-mediated release (5-ASA, Octasa® 1600 mg). SHIME® experiments were performed simulating both the GI physiology and colonic microbiota under healthy and inflammatory bowel disease (IBD) conditions, to study the impact of the disease state and ileal pH variability on colonic 5-ASA delivery. In addition, the effects of the products on the colonic microbiome were investigated by monitoring bacterial growth and metabolites. Results demonstrated that both the prodrug and formulation approaches resulted in a similar percentage of 5-ASA recovery under healthy conditions. On the contrary, during experiments simulating the GI physiology and microbiome of IBD patients (the target population) the formulation strategy resulted in a higher proportion of 5-ASA delivery to the colonic region as compared to the prodrug approach (P < 0.0001). Interestingly, the two products had distinct effects on the synthesis of key bacterial metabolites, such as lactate and short chain fatty acids, which varied according to disease state and ileal pH variability. Further, both 5-ASA and sulfasalazine significantly reduced the growth of the faecal microbiota sourced from six healthy humans. The findings support that the approach selected for colonic drug delivery could significantly influence the effectiveness of UC treatment, and highlight that drugs licensed for UC may differentially impact the growth and functioning of the colonic microbiota.

Pharmacokinetic and safety profiles of mesalazine enema in healthy Chinese subjects: A single- and multiple-dose study

Mesalazine is a well-established treatment for ulcerative colitis by oral or topical administration. However, the pharmacokinetic (PK) and safety profiles of mesalazine administered by an enema has not been clarified in Chinese population. We conducted an open-label study to assess the PK and safety profiles of mesalazine in 11 healthy Chinese subjects after receiving mesalazine enema (1 g/100 mL) once daily for 7 consecutive days. Blood and urine samples were collected for assay of mesalazine and N-acetyl mesalazine by liquid chromatography-tandem mass spectrometry. The PK and safety data were summarized using descriptive statistics. The mean (standard deviation) maximum plasma concentration (Cmax), area under plasma drug concentration-time curve from time 0 to the last measurable plasma concentration time point (AUC0-t) and elimination half-life (t1/2) of mesalazine were 1007.64 (369.00) ng/mL, 9608.59 (3533.08) h·ng/mL and 3.33 (1.99) h, respectively after the first dose administration. In multiple-dose study, the estimated accumulation factor of mesalazine was 1.09. The cumulative urinary excretion rate of parent and major metabolite of mesalazine was 27.77%. After the last doe administration, 2.21% of the administered dose was excreted as mesalazine and 24.47% as N-acetyl mesalazine in urine within 24 h. Overall, 9 adverse events (AEs) were reported in 4 of the 11 subjects (36.4%), including oral ulcer, toothache, upper respiratory tract infection (1 each) and laboratory abnormalities (6 cases). All AEs were mild and recovered spontaneously without treatment, and were not considered as related to mesalazine. Mesalazine enema (1 g/100 mL) was safe and well tolerated in healthy Chinese subjects. These findings support further clinical trials in Chinese patients. Trial registration: This trial was registered to Chinese Clinical Trial Registry (ChiCTR) at https://www.chictr.org.cn (registration number: ChiCTR2300073148).

Potential of Mesalazine Therapeutic Drug Monitoring by Measuring Fecal Excretion in Patients With Ulcerative Colitis

BACKGROUND

Therapeutic drug monitoring of mesalazine (5-ASA) in patients with ulcerative colitis is unavailable. Mucosal 5-ASA concentrations are assumed to be higher during remission, but biopsy is not practical. Therefore, we investigated the feasibility of measuring mesalazine levels in feces. To explore the potential role of fecal mesalazine measurements in therapeutic drug monitoring, we compared the dry fecal concentration and daily fecal excretion of 5-ASA and its metabolite N-acetyl-5-ASA in patients with ulcerative colitis with active and quiescent disease.

METHODS

Adults with ulcerative colitis on oral mesalazine and scheduled for colonoscopy were eligible for inclusion in this cross-sectional study. Stool and urine samples were collected for 48 and 24 hours, respectively, and rectal biopsies were performed. (N-acetyl-)5-ASA was measured using mass spectrometry. Biochemically active disease was defined as a fecal calprotectin level above 100 mcg/g and endoscopically active disease as any activity following the endoscopic Mayo score (≥1).

RESULTS

Approximately 28 patients were included in the study. Daily fecal excretion of (N-acetyl-)5-ASA did not differ between patients with (n = 13) and without (n = 15) endoscopically active disease [median 572 mg/d versus 597 mg/d ( P = 0.86) for 5-ASA and 572 mg/d versus 554 mg/d ( P = 0.86) for N-acetyl-5-ASA]. The same applied to the fecal concentration [median 9.7 mcg/mg dry weight versus 10.3 ( P = 0.53) and 12.0 versus 9.9 ( P = 0.89)]. The results were comparable when the biochemical disease activity definition was used. The mucosal concentrations and urinary excretion of (N-acetyl-)5-ASA did not differentiate between quiescent and active activity.

CONCLUSIONS

Fecal (N-acetyl-)5-ASA measurements do not correlate with disease activity, which renders it an unsuitable tool for therapeutic drug monitoring of mesalazine.

Significance of 5-Aminosalicylic Acid Intolerance in the Clinical Management of Ulcerative Colitis

BACKGROUND

Two major types of 5-aminosalicylic acid (5-ASA)-containing preparations, namely, mesalazine/5-ASA and sulfasalazine (SASP), are currently used as first-line therapy for ulcerative colitis. Recent reports show that optimization of 5-ASA therapy is beneficial for both patient outcomes and healthcare costs. Although 5-ASA and SASP have good efficacy and safety profiles, clinicians occasionally encounter patients who develop 5-ASA intolerance.

SUMMARY

The most common symptoms of acute 5-ASA intolerance syndrome are exacerbation of diarrhea, fever, and abdominal pain. Patients who discontinue 5-ASA therapy because of intolerance have a higher risk of adverse clinical outcomes, such as hospital admission, colectomy, need for advanced therapies, and loss of response to anti-tumor necrosis factor (TNF) biologics. When patients develop symptoms of 5-ASA intolerance, the clinician should consider changing the type of 5-ASA preparation. Recent genome-wide association studies and meta-analyses have shown that 5-ASA allergy is associated with certain single-nucleotide polymorphisms. Although there are no modalities or biomarkers for diagnosing 5-ASA intolerance, the drug-induced lymphocyte stimulation test can be used to assist in the diagnosis of acute 5-ASA intolerance syndrome with high specificity and low sensitivity. This review presents a general overview of 5-ASA and SASP in the treatment of inflammatory bowel disease and discusses the latest insights into 5-ASA intolerance.

KEY MESSAGES

5-ASA is used as first-line therapy for ulcerative colitis. Optimization of 5-ASA may be beneficial for patient outcomes and healthcare systems. Acute 5-ASA intolerance syndrome is characterized by diarrhea, fever, and abdominal pain. Periodic renal function monitoring is recommended for patients receiving 5-ASA.

The insoluble excretion of multi-matrix system mesalazine preparations in patients with ulcerative colitis

BACKGROUND

Multi-matrix mesalazine (MMX) is an important treatment for ulcerative colitis (UC); however, it is often excreted intact, which increases the risk of relapse. This study aimed to clarify the risk factors for insoluble MMX excretion.

METHODS

The subjects were 102 UC patients who were newly prescribed MMX alone to induce remission. Their stools were evaluated on the Bristol Stool Form Scale (BSFS), the presence/absence of insoluble MMX excretion was investigated in interviews, and defecation frequency at the start of treatment and disease type were retrospectively investigated by examining their medical records.

RESULTS

The insoluble excretion rate (IER) was 14.7%. It tended to be higher in the patients with left-sided colitis or extensive colitis, although the differences among the disease types were not significant (p = 0.053). The mean defecation frequency of the patients that reported insoluble MMX excretion was significantly higher than that of the patients that did not report it (6.27 ± 5.28 vs. 3.69 ± 3.17, p < 0.05). The IER tended to be higher among the patients with soft stools (4.5%, 21.9%, and 23.1% in those with BSFS scores of ≤ 4, 5, and ≥ 6, respectively). In ROC analysis of defecation frequency, ≥ 3.5 defecations was found to exhibit sensitivity and specificity of 66.7% and 65.5%, respectively, for predicting insoluble MMX excretion.

CONCLUSIONS

The likelihood of insoluble MMX excretion is influenced by defecation frequency and the extent of inflammation. It is important to keep the possibility of insoluble excretion in mind when prescribing MMX.

5-Aminosalicylic acid ameliorates dextran sulfate sodium-induced colitis in mice by modulating gut microbiota and bile acid metabolism

Colitis develops via the convergence of environmental, microbial, immunological, and genetic factors. The medicine 5-aminosalicylic acid (5-ASA) is widely used in clinical practice for colitis (especially ulcerative colitis) treatment. However, the significance of gut microbiota in the protective effect of 5-ASA on colitis has not been explored. Using a dextran sulfate sodium (DSS)-induced colitis mouse model, we found that 5-ASA ameliorated colitis symptoms in DSS-treated mice, accompanied by increased body weight gain and colon length, and a decrease in disease activity index (DAI) score and spleen index. Also, 5-ASA alleviated DSS-induced damage to colonic tissues, as indicated by suppressed inflammation and decreased tight junction, mucin, and water-sodium transport protein levels. Moreover, the 16S rDNA gene sequencing results illustrated that 5-ASA reshaped the disordered gut microbiota community structure in DSS-treated mice by promoting the abundance of Bifidobacterium, Lachnoclostridium, and Anaerotruncus, and reducing the content of Alloprevotella and Desulfovibrio. Furthermore, 5-ASA improved the abnormal metabolism of bile acids (BAs) by regulating the Farnesoid X receptor (FXR) and Takeda G-protein-coupled receptor 5 (TGR5) signaling pathways in DSS-treated mice. In contrast, 5-ASA did not prevent the occurrence of colitis in mice with gut microbiota depletion, confirming the essential role of gut microbiota in colitis treatment by 5-ASA. In conclusion, 5-ASA can ameliorate DSS-induced colitis in mice by modulating gut microbiota and bile acid metabolism. These findings documented the new therapeutic mechanisms of 5-ASA in clinical colitis treatment.

pH-dependent vs. constant release of mesalazine in the treatment of ulcerative colitis: Do drug delivery concepts determine therapeutic efficacy? (Review)

Inflammatory bowel diseases (IBD) have developed to become a major global health problem. Ulcerative colitis (UC) is one of two main types of IBD, and >90% of patients suffering from mild or moderate forms of UC are treated with mesalazine, a well-tolerated and cost-effective drug. To allow oral administration, the drug has to be protected from resorption before it can reach the affected sites in the colon. The drug is therefore released from most currently used medications either constantly slow (time-dependent) or triggered by an increased pH during gastrointestinal transition. Both variants are widely used in clinical practice and it is surprising that they have not yet been compared directly in a large clinical study. In this overview, the evidence that may suggest preferential use of one type of mesalazine formulation over the other in general or for defined subgroups of patients is summarized and evaluated. Data from in vitro modelling of drug release and measurements of drug concentrations in colonic mucosa suggest that in many cases, constant release and pH-dependent formulations are of similar therapeutic efficiency; however, pH-triggered release may be superior in patients with proctitis-type UC or sites of inflammation in the proximal colon. Additionally, patients with a long gastric residence time, slow small intestinal transition, disease-related diarrhea or sensitivity to systemic adverse effects may benefit more from pH-dependent release formulations. In general, medications based on both concepts show similar efficacies, but the pH-dependent release formulations seem to be more robust in the treatment of a not further classified group of patients with UC. Future comparative clinical studies are required to clearly define the subgroups of patients that should be treated preferably with constant or pH-dependent release formulations of mesalazine.

Factors associated with the persistence of oral 5-aminosalicylic acid monotherapy in ulcerative colitis: a nationwide Norwegian cohort study

BACKGROUND

Oral 5-aminosalicylic acid (5-ASA) is the mainstay treatment of ulcerative colitis (UC) and therapy with oral 5-ASA is associated with beneficial outcomes. We have examined factors associated with the persistence of oral 5-ASA treatment in a national cohort of UC patients.

METHODS

Patients with newly diagnosed UC from 2010 to 2014 using oral 5-ASA monotherapy were identified by combining data from the Norwegian Patient Registry and the Norwegian Prescription Database. The median follow-up time was 1029 days. Drug persistence was defined as duration of oral 5-ASA preparation as monotherapy. Non-persistence of a oral 5-ASA preparation as monotherapy was defined as stopping oral 5-ASA, initiation of any further anti-inflammatory treatment including a course of glucocorticoids and a change to another oral 5-ASA preparation. Drug persistence was analyzed using the Kaplan-Meier method and influence of covariates on drug persistence was analyzed with the Cox proportional hazard model.

RESULTS

A total of 3421 patients were identified. The overall median 5-ASA drug persistence was 179 days. In univariate analyses, persistence was associated with preparation type and high-dose treatment, while oral glucocorticoid use or hospitalization around the start of oral 5-ASA were associated with shorter 5-ASA persistence. In multivariate analyses, oral glucocorticoids [HR 1.67 (1.54-1.80), p < 0.005] and hospitalization around start of 5-ASA [HR 1.23 (1.14-1.34), p < 0.005] were associated with non-persistence, whereas high dose (⩾3 g/day) 5-ASA was associated with longer persistence [HR 0.68 (0.65-0.71), p < 0.005].

CONCLUSION

High-dose treatment with oral 5-ASA was associated with longer persistence of oral 5-ASA monotherapy, whereas the presence of factors indicating more severe disease around initiation of 5-ASA monotherapy was associated with a shorter persistence.

Risk factors and management strategies associated with non-response to aminosalicylates as a maintenance treatment in ulcerative colitis

Aminosalicylates (5-ASA) are used as the first-line maintenance treatment in patients with mild-moderate ulcerative colitis (UC). Early identification of patients at high risk for 5-ASA non-response and appropriate therapeutic escalation are essential to avoid disease progression. However, the absence of a standardized definition for treatment success makes this a challenging task. The focus of the current review was to describe the risk factors and management strategies associated with 5-ASA non-response. Rates of 5-ASA failure can vary from 17 % to 75 % according to different success definitions, of which clinical relapse is the most prevalent and studied condition. Younger age and endoscopic activity at diagnosis, extensive colitis, early need for corticosteroids, elevated inflammatory markers and non-adherence are consistent risk factors of 5-ASA failure. Given the effectiveness, safety profile and tolerability of this medication, therapy optimization is critical before treatment escalation. Combined use of systemic and topical therapy at an appropriate dose in a once-daily administration and control of adherence could improve success rates.

Solving the questions regarding 5-aminosalitylate formulation in the treatment of ulcerative colitis

5-aminosalicylate is a fundamental treatment for patients with ulcerative colitis with mild-to-moderate disease; however, evidence for 5-aminosalicylate treatment is unclear in some situations. This review discusses the clinical guidelines and previous studies, and highlights the following points: (1) Although rectal 5-aminosalicylate is effective for proctitis, physicians should endeavor to reduce patient's distress when administering suppositories or enema as the first-line therapy. It should be clarified whether oral 5-aminosalicylate alone with a drug delivery system that allows higher 5-aminosalicylate concentrations to reach the distal colon would be as effective as rectal 5-aminosalicylate therapy. (2) There has been no direct evidence demonstrating the clinical efficacy of switching the 5-aminosalicylate treatment to other 5-aminosalicylate formulations. However, switching to a different 5-aminosalicylate formulation may be indicated if clinical symptoms are not progressive. (3) Several studies have shown that colonic mucosal 5-aminosalicylate concentration correlates with clinical and endoscopic severity; however, it is unclear whether a high 5-aminosalicylate concentration has therapeutic efficacy. (4) The maximum dose of 5-aminosalicylate is necessary for patients with risk factors for recurrence or hospitalization. (5) Optimization of 5-aminosalicylate dosage may be indicated even for quiescent patients with ulcerative colitis if mucosal healing is not obtained, and if patients have multiple risk factors for recurrence. (6) Furthermore, the discontinuation of 5-aminosalicylate is acceptable when biologics are used. Because there are many "old studies" providing evidence for 5-aminosalicylate formulations, more clinical studies are needed to establish new evidence.