MyMedR

Displaying all 4 publications

Abstract:

Sort:

Fulltext Mast cells in allergy: the potential molecular targets in the upstream signalling pathways

Ji, Wei Tan

Life Sciences, Medicine and Biomedicine, 2018;2(2):13-20.
MyJurnal

Mast cells (MCs) play a crucial role in the pathogenesis of allergic diseases due to their hypersensitive reaction to non-harmful substances that elicit an allergic response. As such, by interrupting certain signalling proteins within the signalling pathway of a MC, an allergic response may be avoided or inhibited. Compounds that attenuate the release of mediators from MCs are known as MC stabilizers. These drugs are clinically used to prevent MC effector responses towards common allergens. Although commonly prescribed clinical MC stabilizers such as disodium cromoglycate and ketotifen fumarate were used in the preventative treatment of various allergic diseases, there still remains a need of advancement towards the discovery of new MC stabilizing drugs that are able to target specific signalling molecules in order to provide better treatment option against these diseases. Among these newly discovered potential MC stabilizers, much efforts have been given to the inhibition of vital upstream signalling molecules such as spleen tyrosine kinase as well as surface receptors such as the high-affinity IgE receptor (FcεRI) and stem cell factor receptor (KIT). A recent study also reported that linker for activation of T cells (LAT) may also be an excellent molecular target for inhibiting MC degranulation. Although in most cases the exact mode of action of these molecules is yet to be elucidated, all these compounds have shown MC inhibition. Therefore, they might have potential therapeutic use in the treatment of allergies and allergy related diseases where MCs are majorly involved. Thus, this mini review will focus on summarising the potential signalling molecules or receptors that have been targeted to inhibit MC degranulation, particularly those located in the upstream signalling pathway.

Matched MeSH terms: Ketotifen
Fulltext Mast cell stabilizing effect of a geranyl acetophenone in dengue virus infection using in vitro model of DENV3-induced RBL-2H3 cells

Tan JW, Wan Zahidi NF, Kow ASF, Soo KM, Shaari K, Israf DA, et al.

Biosci Rep, 2019 06 28;39(6).
PMID: 31110077 DOI: 10.1042/BSR20181273

Mast cells (MCs), a type of immune effector cell, have recently become recognized for their ability to cause vascular leakage during dengue virus (DENV) infection. Although MC stabilizers have been reported to attenuate DENV induced infection in animal studies, there are limited in vitro studies on the use of MC stabilizers against DENV induced MC degranulation. 2,4,6-trihydroxy-3-geranyl acetophenone (tHGA) has been reported to be a potential MC stabilizer by inhibiting IgE-mediated MC activation in both cellular and animal models. The present study aims to establish an in vitro model of DENV3-induced RBL-2H3 cells using ketotifen fumarate as a control drug, as well as to determine the effect of tHGA on the release of MC mediators upon DENV infection. Our results demonstrated that the optimal multiplicities of infection (MOI) were 0.4 × 10-2 and 0.8 × 10-2 focus forming units (FFU)/cell. Ketotifen fumarate was proven to attenuate DENV3-induced RBL-2H3 cells degranulation in this in vitro model. In contrast, tHGA was unable to attenuate the release of both β-hexosaminidase and tumor necrosis factor (TNF)-α. Nonetheless, our study has successfully established an in vitro model of DENV3-induced RBL-2H3 cells, which might be useful for the screening of potential MC stabilizers for anti-dengue therapies.

Matched MeSH terms: Ketotifen/pharmacology; Ketotifen/chemistry
Fulltext Mechanistic Studies of the Antiallergic Activity of Phyllanthus amarus Schum. & Thonn. and Its Compounds

Abd Rani NZ, Lam KW, Jalil J, Mohamad HF, Mat Ali MS, Husain K

Molecules, 2021 Jan 28;26(3).
PMID: 33525733 DOI: 10.3390/molecules26030695

Phyllanthus amarus Schum. & Thonn. (Phyllanthaceae) is a medicinal plant that is commonly used to treat diseases such as asthma, diabetes, and anemia. This study aimed to examine the antiallergic activity of P. amarus extract and its compounds. The antiallergic activity was determined by measuring the concentration of allergy markers release from rat basophilic leukemia (RBL-2H3) cells with ketotifen fumarate as the positive control. As a result, P. amarus did not stabilize mast cell degranulation but exhibited antihistamine activity. The antihistamine activity was evaluated by conducting a competition radioligand binding assay on the histamine 1 receptor (H1R). Four compounds were identified from the high performance liquid chromatography (HPLC) analysis which were phyllanthin (1), hypophyllanthin (2), niranthin (3), and corilagin (4). To gain insights into the binding interactions of the most active compound hypophyllanthin (2), molecular docking was conducted and found that hypophyllanthin (2) exhibited favorable binding in the H1R binding site. In conclusion, P. amarus and hypophyllanthin (2) could potentially exhibit antiallergic activity by preventing the activation of the H1 receptor.

Matched MeSH terms: Ketotifen/pharmacology
Fulltext A Prospective Study on the Prevalence, Extent of Disease and Outcome of Eosinophilic Gastroenteritis in Patients Presenting with Lower Abdominal Symptoms

Hui CK, Hui NK

Gut Liver, 2018 May 15;12(3):288-296.
PMID: 29212311 DOI: 10.5009/gnl17056

Background/Aims: The epidemiology of eosinophilic gastroenteritis remains unclear. We aim to determine the prevalence of eosinophilic gastroenteritis in patients with lower abdominal symptoms.
Methods: In a prospective study, colonoscopy was performed on 2,469 consecutive patients. Biopsies were taken from the terminal ileum and ascending, transverse, descending and sigmoid colon in all patients.
Results: Sixty-four of the 2,469 patients (2.6%) had eosinophilic gastroenteritis. Only five of the 64 patients (7.8%) with eosinophilic gastroenteritis had endoscopic mucosal abnormalities during colonoscopy. Six of these 64 patients (9.4%) had severe disease at presentation, and seven of these 64 patients (10.9%) required systemic steroid treatment. An elevated absolute peripheral eosinophil count was independently associated with severe disease at presentation (4/6 [66.7%] vs 3/58 [5.2%], p=0.005; odds ratio [OR], 25.320; 95% confidence interval [CI], 2.628 to 243.910), and severe disease at the time of presentation was independently associated with the use of systemic steroid treatment (6/7 [85.7%] vs 0/57 [0%], p=0.008; OR, 18.021; 95% CI, 2.163 to 150.152).
Conclusions: The prevalence of eosinophilic gastroenteritis is common, and patients usually present normal-appearing mucosa on colonoscopy. Those with severe disease at presentation usually have a raised absolute peripheral eosinophil count and should be commenced on systemic steroids as an initial therapy.

Matched MeSH terms: Ketotifen/administration & dosage