Sickle cell anemia (SCA) is an inherited disorder associated with severe life-long pain and significant morbidity. The mechanisms of pain in SCA remain poorly understood. We show that mast cell activation/degranulation contributes to sickle pain pathophysiology by promoting neurogenic inflammation and nociceptor activation via the release of substance P in the skin and dorsal root ganglion. Mast cell inhibition with imatinib ameliorated cytokine release from skin biopsies and led to a correlative decrease between GMCSF and white blood cells in sickle mice. Targeting mast cells by genetic mutation or pharmacologic inhibition with imatinib ameliorates tonic hyperalgesia and prevents hypoxia/reoxygenation-induced hyperalgesia in sickle mice. Pre-treatment with the mast cell stabilizer Cromolyn sodium improved analgesia following low doses of morphine that would otherwise be ineffective. Mast cell activation therefore underlies sickle pathophysiology leading to inflammation, vascular dysfunction, pain and requirement for high doses of morphine. Pharmacological targeting of mast cells with imatinib may be a suitable approach to address pain and perhaps treat SCA.

A great number of people are suffering from allergic inflammatory disease such as asthma, atopic dermatitis, and sinusitis. Therefore discovery of drugs for the treatment of these diseases is an important subject in human health. In this study, we investigated anti-allergic inflammatory effect of galangin and underlying mechanisms of action using in vitro and in vivo models. Galangin inhibited histamine release by the reduction of intracellular calcium in phorbol 12-mystate 13-acetate plus calcium ionophore A23187-stimulated human mast cells (HMC-1). Galangin decreased expression of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, and IL-8. The inhibitory effect of galangin on theses pro-inflammatory cytokines was related with c-Jun N-terminal kinases, and p38 mitogen-activated protein kinase, nuclear factor-κB, and caspase-1. Furthermore, galangin attenuated IgE-mediated passive cutaneous anaphylaxis and the expression of histamine receptor 1 at the inflamed tissue. The inhibitory effects of galangin were more potent than cromolyn, a known anti-allergic drug. Our results showed that galangin down-regulates mast cell-derived allergic inflammatory reactions by blocking histamine release and expression of pro-inflammatory cytokines. In light of in vitro and in vivo anti-allergic inflammatory effects, galangin could be a beneficial anti-allergic inflammatory agent.

Serotonin [5-hydroxytryptamine (5-HT)] is released from enterochromaffin cells in the mucosa of the small intestine. We tested a hypothesis that elevation of 5-HT in the environment of enteric mast cells might degranulate the mast cells and release mediators that become paracrine signals to the enteric nervous system, spinal afferents, and secretory glands. Western blotting, immunofluorescence, ELISA, and pharmacological analysis were used to study expression of 5-HT receptors by mast cells in the small intestine and action of 5-HT to degranulate the mast cells and release histamine in guinea pig small intestine and segments of human jejunum discarded during Roux-en-Y gastric bypass surgeries. Mast cells in human and guinea pig preparations expressed the 5-HT1A receptor. ELISA detected spontaneous release of histamine in guinea pig and human preparations. The selective 5-HT1A receptor agonist 8-hydroxy-PIPAT evoked release of histamine. A selective 5-HT1A receptor antagonist, WAY-100135, suppressed stimulation of histamine release by 5-HT or 8-hydroxy-PIPAT. Mast cell-stabilizing drugs, doxantrazole and cromolyn sodium, suppressed the release of histamine evoked by 5-HT or 8-hydroxy-PIPAT in guinea pig and human preparations. Our results support the hypothesis that serotonergic degranulation of enteric mast cells and release of preformed mediators, including histamine, are mediated by the 5-HT1A serotonergic receptor. Association of 5-HT with the pathophysiology of functional gastrointestinal disorders (e.g., irritable bowel syndrome) underlies a question of whether selective 5-HT1A receptor antagonists might have therapeutic application in disorders of this nature.

OBJECTIVE::

Cardiac surgery, especially when employing cardiopulmonary bypass and deep hypothermic circulatory arrest, is associated with systemic inflammatory responses that significantly affect morbidity and mortality. Intestinal perfusion abnormalities have been implicated in such responses, but the mechanisms linking local injury and systemic inflammation remain unclear. Intestinal mast cells are specialized immune cells that secrete various preformed effectors in response to cellular stress. We hypothesized that mast cells are activated in a microenvironment shaped by intestinal ischemia/reperfusion, and investigated local and systemic consequences.

DESIGN:

: Rat model of deep hypothermic circulatory arrest.

SETTING:

: University research laboratory.

SUBJECTS:

: Twelve- to 14-week-old male Sprague-Dawley rats.

INTERVENTIONS:

: Rats were anesthetized and cooled to 16°C-18°C on cardiopulmonary bypass before instituting deep hypothermic circulatory arrest for 45 minutes. Specimens were harvested following rewarming and 2 hours of recovery.

MEASUREMENTS AND MAIN RESULTS:

: Significant intestinal barrier disruption was found, together with macro- and microscopic evidence of ischemia/reperfusion injury in ileum and colon, but not in lungs or kidneys. Immunofluorescence and toluidine blue staining revealed increased numbers of mast cells and their activation in the gut. In animals pretreated with the mast cell stabilizer, cromolyn sodium, mast cell degranulation was blocked, and intestinal morphology and barrier function were preserved following deep hypothermic circulatory arrest. Furthermore, cromolyn sodium treatment was associated with reduced intestinal neutrophil influx and blunted systemic release of proinflammatory cytokines.

CONCLUSION:

: Our data provide primary evidence that intestinal ischemia/reperfusion is a leading pathophysiologic process in a rat model of deep hypothermic circulatory arrest, and that intestinal injury, and local and systemic inflammatory responses are critically dependent on mast cell activation. This identifies intestinal mast cells as central players in deep hypothermic circulatory arrest-associated responses, and opens novel therapeutic possibilities for patients undergoing this procedure.

Intrathecal morphine forms granulomas that arise from the adjacent arachnoid membrane. The authors propose that these inflammatory cells exit the meningeal vasculature secondary to meningeal mast cell degranulation.Three sets of experiments were accomplished in dogs: (1) ex vivo meningeal mast cell degranulation (histamine release was measured ex vivo from canine dura incubated with opiates); (2) in vivo cutaneous mast cell degranulation (flare areas on the dog abdomen were measured after subcutaneous opiates); and (3) in vivo granuloma pharmacology. Dogs with lumbar intrathecal catheters received infusion of intrathecal saline or intrathecal morphine. Intrathecal morphine dogs received (1) no other treatment (control); (2) twice-daily subcutaneous naltrexone; (3) intrathecal co-infusion of cromolyn; or (4) twice-daily subcutaneous cromolyn for the 24- to 28-day study course.Morphine but not fentanyl evoked dural histamine release, which was blocked by cromolyn but not naloxone. Wheal/flare was produced by subcutaneous morphine, methadone, hydromorphone, but not fentanyl, and was unaffected by naltrexone but prevented by cromolyn. Granulomas occurred in all dogs receiving intrathecal morphine (15 of 15); subcutaneous naltrexone had no effect on granulomas (six of six) but was reduced by concurrent intrathecal cromolyn (zero of five) or twice-daily subcutaneous cromolyn (one of five).The pharmacology of cutaneous/dural mast cell degranulation and intrathecal granulomas are comparable, not mediated by opioid receptors, and reduced by agents preventing mast cell degranulation. If an agent produces cutaneous mast cell degranulation at concentrations produced by intrathecal delivery, the agent may initiate granulomas.

Lysophosphatidic acid (LPA), a bioactive lysophospholipid, accumulates in the atherosclerotic plaque. It has the capacity to activate mast cells, which potentially exacerbates plaque progression. In this study, we thus aimed to investigate whether LPA contributes to plaque destabilization by modulating mast cell function. We here show by an imaging mass spectrometry approach that several LPA species are present in atherosclerotic plaques. Subsequently, we demonstrate that LPA is a potent mast cell activator which, unlike other triggers, favors release of tryptase. Local perivascular administration of LPA to an atherosclerotic carotid artery segment increases the activation status of perivascular mast cells and promotes intraplaque hemorrhage and macrophage recruitment without impacting plaque cell apoptosis. The mast cell stabilizer cromolyn could prevent intraplaque hemorrhage elicited by LPA-mediated mast cell activation. Finally, the involvement of mast cells in these events was further emphasized by the lack of effect of perivascular LPA administration in mast cell deficient animals. We demonstrate that increased accumulation of LPA in plaques induces perivascular mast cell activation and in this way contributes to plaque destabilization in vivo. This study points to local LPA availability as an important factor in atherosclerotic plaque stability.

Allergic rhinitis is the most common atopic disorder seen in ENT clinics. It is diagnosed by history, physical exam and objective testing. Patient education, environmental control measures, pharmacotherapy, and allergen-specific immunotherapy are the cornerstones of allergic rhinitis treatment and can significantly reduce the burden of disease. Current treatment guidelines include antihistamines, intranasal corticosteroids, oral and intranasal decongestants, intranasal anticholinergics, intranasal cromolyn, and leukotriene receptor antagonists. In the mechanism of allergic rhinitis, histamine is responsible for major allergic rhinitis symptoms such as rhinorrhea, nasal itching and sneezing. Its effect on nasal congestion is less evident. In contrast, leukotrienes result in increase in nasal airway resistance and vascular permeability. Antihistamines and leukotriene receptor antagonists are commonly used in the treatment of allergic rhinitis. The published literature about combined antihistamines and leukotriene antagonists in mono- or combination therapy is reviewed and presented.

Abstract We previously reported the inhibitory profiles of naproxen and cromolyn against glycogen synthase kinase-3β, which partly explain the molecular mechanisms of their anti-cancer properties. In this study, we performed a detailed biochemical evaluation of the two drugs against colorectal adenocarcinoma (Caco2), hepatocellular carcinoma (HepG2), mammary gland carcinoma (MCF7), epitheloid cervix carcinoma (Hela), lung carcinoma (A5W9) and epidermoid larynx carcinoma (Hep2) cell lines. Additionally, we performed cellular viability tests using trypan blue, proliferation MTT assay, apoptosis, p53 and real-time polymerase chain reaction for gene expression of survivin and caspase-3. Not only the two drugs were found to significantly reduce the viability of different cell lines, but they also were shown to have potent dose-dependent reduction of cellular proliferation. They exhibited cytotoxicity IC(50) values of 3.69 and 4.16 μM for naproxen and cromolyn, respectively. Viability and proliferation results clearly correlated with apoptosis and p53 experiments in showing that both drugs significantly raised apoptotic percentages. Furthermore, we observed a significant reduction in survivin and elevation of caspase-3 gene expression upon exposure to the two drugs. It can be concluded that both naproxen and cromolyn have significant anti-cancer properties.

We have previously shown that the antiallergic drug cromolyn blocks S100P interaction with its receptor receptor for advanced glycation end product (RAGE) and improves gemcitabine effectiveness in pancreatic ductal adenocarcinoma (PDAC). However, the concentration required to achieve its effectiveness was high (100 μmol/L). In this study, we designed and synthesized analogs of cromolyn and analyzed their effectiveness compared with the parent molecule. An ELISA was used to confirm the binding of S100P with RAGE and to test the effectiveness of the different analogs. Analog 5-methyl cromolyn (C5OH) blocked S100P binding as well as the increases in NF-κB activity, cell growth, and apoptosis normally caused by S100P. In vivo C5OH systemic delivery reduced NF-κB activity to a greater extent than cromolyn and at 10 times lesser dose (50 mg vs. 5 mg). Treatment of mice-bearing syngeneic PDAC tumors showed that C5OH treatment reduced both tumor growth and metastasis. C5OH treatment of nude mice bearing orthotopic highly aggressive pancreatic Mpanc96 cells increased the overall animal survival. Therefore, the cromolyn analog, C5OH, was found to be more efficient and potent than cromolyn as a therapeutic for PDAC. Mol Cancer Ther; 12(5); 654-62. ©2013 AACR.

To explore the effects of cromolyn sodium (CS) on intestinal ischemia-reperfusion (IIR) and its relationship with mast cell activation and protease-activated receptor 2 (PAR-2) expression.A total of 32 SD rats were randomly divided into 4 groups: sham-operated (S), intestinal ischemia reperfusion (IIR), CS (a mast cell stabilizer, CS, 25 mg/kg) and compound 48/80 (a mast cell degranulator, CP, 0.75 mg/kg) (n = 8 each). IIR was induced by clamping superior mesenteric artery for 75 min followed by reperfusion for 3 hours. The above agents were intravenously administrated at 5 min pre-reperfusion. Rats were then sacrificed and intestinal issues harvested for histological examinations. The tryptase expression and mast cell count were analyzed by immunohistochemistry. PAR-2 was analyzed by Western blot.The Chiu's score (0.75 ± 0.21), mast cell count (10 ± 3), tryptase expression (125 ± 15) and PAR-2 expression (109 ± 10) of group S were the least while those of group CP the most (all P < 0.05). The Chiu's score (2.14 ± 0.64), mast cell count (15 ± 4), tryptase expression (138 ± 17) and PAR-2 expression (124 ± 12) of group CS were less than those of groups IIR and CP (all P < 0.05).Cromolyn sodium may reduce IIR injury by stabilizing mast cell membrane and inhibiting the expressions of tryptase and PAR-2.