Histamine H1-receptor antagonists with immunomodulating activities: potential use for modulating T helper type 1 (Th1)/Th2 cytokine imbalance and inflammatory responses in allergic diseases

DNA methylation profiling reveals potential biomarkers of β-lactams induced fatal anaphylactic shock

Anaphylaxis is a serious reaction of systemic hypersensitivity with that rapid onset and sudden death. Drug hypersensitivity, particularly induced by β-lactams, is one of the most frequent causes of anaphylaxis in adults. But identification of anaphylactic shock, in forensic sciences recently, is difficult, because it mainly depends on nonspecific characteristic morphological changes, as well as exclusion and circumstantial evidence. Here, we detected DNA methylation signatures of β-lactams-induced fatal anaphylactic shock with the Illumina Infinium Human Methylation EPIC BeadChip, to screen potential forensic biomarkers and reveal the molecular mechanisms of drug-induced anaphylaxis with fatal shock and sudden death. Our results indicated that DNA methylation was associated with β-lactams-induced fatal anaphylactic shock, in which the hypomethylation played a vital role. We found that 1459 differentially methylated positions (DMPs) were mainly involved in β-lactams-induced fatal anaphylactic shock by regulating MAPK and other signaling pathways. 18 DNA methylation signatures that could separate β-lactams-induced anaphylactic shock from healthy individuals were identified. The altered methylation of DMPs can affect the transcription of corresponding genes and promote β-lactams-induced fatal anaphylactic shock. The results suggest that DNA methylation can detect forensic identification markers of drug-induced anaphylaxis with fatal shock and sudden death, and it is an effective method for the forensic diagnosis.

A forskolin-mediated increase in cAMP promotes T helper cell differentiation into the Th1 and Th2 subsets rather than into the Th17 subset

The adenylyl cyclase (AC) signaling pathway is suggested to be a key regulator of immune system functions. However, specific effects of cyclic adenosine monophosphate (cAMP) on T helper (Th) cell differentiation and functions are unclear. The involvement of cAMP in the Th cell differentiation program, in particular the development of Th1, Th2, and Th17 subsets, was evaluated employing forskolin (FSK), a labdane diterpene well known as an AC activator. FSK mediated an elevation in Th1-specific markers reinforcing the Th1 cell phenotype. The Th2 differentiation was supported by FSK, though cell metabolism was negatively affected. In contrast, the Th17 immunophenotype was severely suppressed leading to the highly specific upregulation of CXCL13. The causality between FSK-elicited cAMP production and the observed reinforcement of Th2 differentiation was established by using AC inhibitor 2',5'-dideoxyadenosine, which reverted the FSK effects. Overall, an FSK-mediated cAMP increase affects Th1, Th2 and Th17 differentiation and can contribute to the identification of novel therapeutic targets for the treatment of Th cell-related pathological processes.

Efficacy of Targeted Mast Cell Inhibition Therapy in Chronic Prostatitis/Chronic Pelvic Pain Syndrome

OBJECTIVE

To identify a subgroup of patients with mast cell dysfunction in chronic prostatitis/chronic pelvic pain syndrome and evaluate efficacy of mast cell-directed therapy.

MATERIALS AND METHODS

Men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) were recruited and evaluated in an open-label, interventional uncontrolled trial after therapy with cromolyn sodium and cetirizine hydrochloride. The primary endpoint was a change in mast cell tryptase concentrations after treatment while secondary endpoints were changes in the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) and AUA-SI. Isolated cells from postprostatic massage urine were evaluated for immune changes using mRNA expression analysis.

RESULTS

31 patients with a diagnoses of Category III CP/CPPS were consented, 25 patients qualified and 20 completed the study after meeting a prespecified threshold for active tryptase in expressed prostatic secretions. After treatment with cromolyn sodium and cetirizine dihydrochloride for 3-week, active tryptase concentrations were significantly reduced from 49.03±14.05 ug/mL to 25.49±5.48 ug/mL (P<.05). The NIH-CPSI total score was reduced with a mean difference of 5.2±1 along with reduction in the pain, urinary and quality of life subscores (P<.001). A reduction in the AUA-SI was observed following treatment (P<.05). NanoString mRNA analysis of isolated cells revealed downregulation of immune-related pathways including Th1 and Th17 T cell differentiation and TLR signaling. Marked reduction in CD45+ cells and specifically macrophages and neutrophil abundance was observed.

CONCLUSION

Identification of CP/CPPS patients with mast cell dysfunction may be achieved using tryptase as a discriminating biomarker. Mast cell-directed therapy in this targeted subgroup may be effective in reducing symptoms and modulating the immune inflammatory environment.

Addition of oral Fexofenadine to topical therapy leads to a significantly greater reduction in the serum IL-31 levels in mild to moderate pediatric atopic dermatitis

BACKGROUND

Recent evidence has suggested that oral antihistamines could have a beneficial role in atopic dermatitis (AD) due to their anti-inflammatory action. Hence, we aimed to evaluate the effectiveness of adding an oral second generation, non-sedating, H1 antihistamine (Fexofenadine) to topical treatment in AD.

MATERIALS AND METHODS

In this prospective randomized study, a total of 50 patients with a diagnosis of mild to moderate atopic dermatitis were recruited and randomized into two groups A (appropriate topical treatment combined with oral fexofenadine) and B (appropriate topical treatment without oral fexofenadine). Both groups received the respective treatments for a duration of 8 weeks.

RESULTS

There was no significant difference between the two groups in terms of SCORAD and the 5-D Itch Score at any of the time points (2 weeks, 4 weeks, 8 weeks). However, the serum IL-31 (ng/ml) decreased significantly from baseline in the fexofenadine group after 8 weeks of treatment.

CONCLUSIONS

Although we could not conclusively confirm the clinical efficacy of adding oral fexofenadine to topical treatment in AD, serological evaluation indicates that fexofenadine treatment can lead to significant lowering of serum IL-31 levels in AD patients.

Nationwide paediatric cohort study of a protective association between allergy and complicated appendicitis

BACKGROUND

In a nationwide cohort the potentially protective association between allergy and complicated appendicitis was analysed, and the influence of seasonal antigens, antihistamine treatment, and timing of allergy onset assessed.

METHODS

Some 1 112 571 children born between 2000 and 2010 were followed from birth until the end of 2014. A cross-sectional analysis of appendicitis cases, with comparison of allergic versus non-allergic children for absolute risk and odds of complicated appendicitis was first undertaken. This was followed by a longitudinal analysis of children with allergy and matched controls who had never had an allergy, for incidence rate and hazard of subsequent complicated or simple appendicitis.

RESULTS

Of all children, 20.4 per cent developed allergy and 0.6 per cent had appendicitis during follow-up. Among children with appendicitis, complicated appendicitis was more common among non-allergic children (18.9 per cent, 948 of 5016) than allergic children (12.8 per cent, 173 of 1351) (P < 0.001), and allergic children had a lower adjusted odds of complicated appendicitis (adjusted odds ratio (OR) 0.80, 95 per cent c.i. 0.67 to 0.96; P = 0.021). The risk of complicated appendicitis among children with manifest allergy was reduced by one-third in the longitudinal analysis (incidence rate 0.13 versus 0.20 per 1000 person-years; hazard ratio (HR) 0.68, 95 per cent c.i. 0.58 to 0.81; P < 0.001), whereas the risk of simple appendicitis remained unchanged (incidence rate 0.91 versus 0.91; HR 1.00, 0.94 to 1.07; P = 0.932). Seasonal antigen exposure was a protective factor (adjusted OR 0.82, 0.71 to 0.94; P = 0.004) and ongoing antihistamine medication a risk factor (adjusted OR 2.28, 1.21 to 4.28; P = 0.012).

CONCLUSION

Children with allergy have a lower risk of complicated appendicitis, but the same overall risk of simple appendicitis. Seasonal antigen exposure reduced, and antihistamine treatment increased, the risk of complicated disease.

Mast cell function in prostate inflammation, fibrosis, and smooth muscle cell dysfunction

Intraurethral inoculation of mice with uropathogenic Escherichia coli (CP1) results in prostate inflammation, fibrosis, and urinary dysfunction, recapitulating some but not all of the pathognomonic clinical features associated with benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). In both patients with LUTS and CP1-infected mice, we observed increased numbers and activation of mast cells and elevated levels of prostate fibrosis. Therapeutic inhibition of mast cells using a combination of a mast cell stabilizer, cromolyn sodium, and the histamine 1 receptor antagonist cetirizine di-hydrochloride in the mouse model resulted in reduced mast cell activation in the prostate and significant alleviation of urinary dysfunction. Treated mice showed reduced prostate fibrosis, less infiltration of immune cells, and decreased inflammation. In addition, as opposed to symptomatic CP1-infected mice, treated mice showed reduced myosin light chain-2 phosphorylation, a marker of prostate smooth muscle contraction. These results show that mast cells play a critical role in the pathophysiology of urinary dysfunction and may be an important therapeutic target for men with BPH/LUTS.NEW & NOTEWORTHY LUTS-associated benign prostatic hyperplasia is derived from a combination of immune activation, extracellular matrix remodeling, hyperplasia, and smooth muscle cell contraction in prostates of men. Using a mouse model, we describe the importance of mast cells in regulating these multiple facets involved in the pathophysiology of LUTS. Mast cell inhibition alleviates both pathology and urinary dysfunction in this model, suggesting the potential for mast cell inhibition as a therapeutic that prevents and reverses pathology and associated symptomology.

Drug repurposing screens reveal cell-type-specific entry pathways and FDA-approved drugs active against SARS-Cov-2

There is an urgent need for antivirals to treat the newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To identify new candidates, we screen a repurposing library of ∼3,000 drugs. Screening in Vero cells finds few antivirals, while screening in human Huh7.5 cells validates 23 diverse antiviral drugs. Extending our studies to lung epithelial cells, we find that there are major differences in drug sensitivity and entry pathways used by SARS-CoV-2 in these cells. Entry in lung epithelial Calu-3 cells is pH independent and requires TMPRSS2, while entry in Vero and Huh7.5 cells requires low pH and triggering by acid-dependent endosomal proteases. Moreover, we find nine drugs are antiviral in respiratory cells, seven of which have been used in humans, and three are US Food and Drug Administration (FDA) approved, including cyclosporine. We find that the antiviral activity of cyclosporine is targeting Cyclophilin rather than calcineurin, revealing essential host targets that have the potential for rapid clinical implementation.

Reduced CD4+T Cell CXCR3 Expression in Patients With Allergic Rhinitis

While T cells are considered to play a primary role in IgE-mediated atopic diseases, little is known about the systemic variations of T cell subsets from patients with allergic rhinitis (AR). To elucidate the characteristics of peripheral T cells, we analyzed natural killer, B cell, and T cell populations, performed T cell subset construction, and assessed chemokine receptor and associated serum cytokine expression in 25 AR patients and 20 healthy controls. Our results revealed increased levels of CD4⁺T cells, serum interleukin (IL)-10, IL-6, and interferon (IFN)-γ, and reduced Th1 and Th17 subsets, identified by their chemokine receptors, in AR patients. These results suggest a systemic activation of T cell responses in AR. We further demonstrated that AR patients exhibit significantly reduced CD4⁺T cell CXCR3 expression, especially in patients with moderate-severe disease severity, demonstrating that CXCR3 is a potential key molecule that hinders the Th1/Th2 balance in AR pathology. Overall, systemic T cell activation occurred in AR patients and CXCR3 dramatically decreased in CD4⁺T cells, which may ultimately be used as a potential disease and/or therapeutic target.

CARsomes inhibit airway allergic inflammation in mice by inducing antigen-specific Th2 cell apoptosis

BACKGROUND

Skewed T helper (Th)2 response plays a crucial role in the pathogenesis of allergic diseases. The therapeutic efficacy for allergic diseases is unsatisfactory currently. This study aims to regulate the skewed Th2 response with CARsomes.

METHODS

The CARsome consisted of an epitope of Dermatophagoides farina-1 (Derf1), a segment of the anti-DEC205 antibody, the scFv, and an open reading frame of perforin. This fusion protein binds to DEC205 molecule on the surface of exosomes derived from dendritic cells (DC). The effects of CARsome on inducing antigen (Ag)-specific Th2 cell apoptosis were assessed both in vivo and in vitro.

RESULTS

Exposure to CARsomes in the culture induced Ag-specific Th2 cell apoptosis. Injection of CARsomes through the vein puncture also induced Ag-specific Th2 cell apoptosis in the lungs of sensitized mice. CARsomes could induce Ag-specific regulatory T cells. Administration of CARsomes efficiently inhibited experimental allergic airway inflammation.

CONCLUSIONS

The CARsomes can inhibit allergic airway inflammation by inducing Ag-specific Th2 cell apoptosis and induce Ag-specific regulatory T cells. The data suggest that CARsomes have the translational potential to be used to treat allergic airway inflammation.

Second-Generation Histamine H1 Receptor Antagonists Suppress Delayed Rectifier K+-Channel Currents in Murine Thymocytes

BACKGROUND/AIMS

Voltage-dependent potassium channels (Kv1.3) are predominantly expressed in lymphocyte plasma membranes. These channels are critical for the activation and proliferation of lymphocytes. Since second-generation antihistamines are lipophilic and exert immunomodulatory effects, they are thought to affect the lymphocyte Kv1.3-channel currents.

METHODS

Using the patch-clamp whole-cell recording technique in murine thymocytes, we tested the effects of second-generation antihistamines, such as cetirizine, fexofenadine, azelastine, and terfenadine, on the channel currents and the membrane capacitance.

RESULTS

These drugs suppressed the peak and the pulse-end currents of the channels, although the effects of azelastine and terfenadine on the peak currents were more marked than those of cetirizine and fexofenadine. Both azelastine and terfenadine significantly lowered the membrane capacitance. Since these drugs did not affect the process of endocytosis in lymphocytes, they were thought to have interacted directly with the plasma membranes.

CONCLUSIONS

Our study revealed for the first time that second-generation antihistamines, including cetirizine, fexofenadine, azelastine, and terfenadine, exert suppressive effects on lymphocyte Kv1.3-channels. The efficacy of these drugs may be related to their immunomodulatory mechanisms that reduce the synthesis of inflammatory cytokine.

Langerhans cell-like dendritic cells treated with ginsenoside Rh2 regulate the differentiation of Th1 and Th2 cells in vivo

Ginsenoside Rh2 is one of the rare ginsenosides extracted from Panax ginseng C. A. Mey. The anti-allergic activity of ginsenoside Rh2 has been documented in some literature. In this work, an anti-allergic mechanism of ginsenoside Rh2 was investigated by focusing on the differentiation of T cells through Langerhans cells (LCs). Langerhans cell-like dendritic cells (LDCs) were generated in vitro and were used as substitute for LCs.In vivo the mRNA expression for IFN-γ and CXCR3 of T cells was increased after being injected with ginsenoside Rh2-treated LDCs thereby increasing the concentration of IFN-γ in the culture supernatants of CD3+/CD28+ T lymphocytes. However,in vitro, the expression of mRNA for CD40 and CD80 on ginsenoside Rh2-treated LDCs was up-regulated significantly and the endocytic activity of LDCs was down-regulated slightly. These findings indicate that T cells differentiation could be regulated by ginsenoside Rh2 through LDCs in vivo by altering the antigen presenting capacity, maturation and phagocytosis of LDCs.

Inhibitory effects of bisdemethoxycurcumin on mast cell-mediated allergic diseases

Most allergic reactions are induced by mast cell activation. Mast cells play vital roles in the pathogenesis of allergic diseases. Bisdemethoxycurcumin (BDMC), a natural curcuminoid, has potential anti-allergic effects. Hence, we explored the effect of BDMC on mast cell-mediated allergic diseases. The study proved that BDMC suppresses β-hexosaminidase release, granule release, and membrane ruffling in monoclonal anti-2,4,6-dinitrophenyl-immunoglobulin (Ig) E/human serum albumin (DNP-IgE/HSA)-stimulated rat basophilic leukaemia cells (RBL-2H3 cells), and BDMC suppressed ovalbumin (OVA)-induced allergic rhinitis (AR) symptoms and OVA-specific IgE levels in AR mice. Furthermore, BDMC increased the survival of compound 48/80 anaphylaxis shock mice and elevated the decreased rectal temperature in OVA-induced active systemic anaphylaxis mice. These findings indicate that BDMC regulates the degranulation of mast cells, demonstrating its potential in the treatment of mast cell-induced allergic reactions.

Duration of topical therapy in the maintenance of atopic dermatitis remission in pediatric age

BACKGROUND

Topical corticosteroids (TCS) are the first-choice treatment for atopic dermatitis (AD) flares. In literature there are clear advice about the potency, dosage and frequency of application of TCS, but there are no shared indications about duration of the treatment during a flare. The aim of the study is to demonstrate if the use of a steroid cream for less than or 5 days, could be equal or more effective than the application for more than 5 days during a flare episode, in keeping a remission state of AD.

METHODS

The study population (N.=122) was selected according to the following inclusion criteria: at least one specialist allergological and dermatological examination in the period November 2015 to February 2017, age between 1 and 11 years; mild to moderate atopic dermatitis. All patients were given a standardized telephone questionnaire, which concerns on multiple aspects: parents' self-reported perceptions of the severity of their child's condition; actual use of emollients, moisturizers and steroid creams; number of consecutive days of using of topical steroid cream during an exacerbation of AD; average number of AD exacerbations per month in the last year; total number of AD exacerbations in the last year.

RESULTS

Data from 96 patients was examined. We classified three groups of patients from data collected: group 1 (N.=40): use of TCS for ≤5 consecutive days during an exacerbation event of AD; group 2 (N.=12): use of TCS for >5 consecutive days during an exacerbation event of AD; group 3 (N.=44): nonuse of TCS or use of TCS with a different posology. We found a further subgroup in group 3 (3a, N.=27) with patients using only emollient crème in AD management. In group 1, 27 patients (67.5%) did not show a good AD control; on the contrary, 13 patients (27.5%) reported a good AD control. In group 2, 4 patients (25%) did not show a good AD control; on the contrary, 8 patients (75%) reported a good AD control. By comparing the data obtained in the presence of good AD control, the difference between the percentages obtained was found to be statistically significant (P=0.034).

CONCLUSIONS

The results obtained show that a therapeutic pattern based on the use of TCS for a duration of more than 5 consecutive days during an episode of AD exacerbation is more efficient than the proposed alternative therapeutic scheme in the maintenance of AD remission.

Silkworm dropping extract ameliorate trimellitic anhydride-induced allergic contact dermatitis by regulating Th1/Th2 immune response

Allergic contact dermatitis (ACD) is an inflammatory skin disease caused by hapten-specific immune response. Silkworm droppings are known to exert beneficial effects during the treatment of inflammatory diseases. Here, we studied whether topical treatment and oral administration of silkworm dropping extract (SDE) ameliorate trimellitic anhydride (TMA)-induced ACD. In ACD mice model, SDE treatment significantly suppressed the increase in both ear thickness and serum IgE levels. Furthermore, IL-1β and TNF-α levels were reduced by SDE. In allergic responses, SDE treatment significantly attenuated the production of the Th2-associated cytokine IL-4 in both ear tissue and draining lymph nodes. However, it increased the production of the Th1-mediated cytokine IL-12. Thus, these results showed that SDE attenuated TMA-induced ACD symptoms through regulation of Th1/Th2 immune response. Taken together, we suggest that SDE treatment might be a potential agent in the prevention or therapy of Th2-mediated inflammatory skin diseases such as ACD and atopic dermatitis.

ABBREVIATIONS

ACD: allergic contact dermatitis; AD: atopic dermatitis; APC: antigen presenting cells; CCL: chemokine (C-C motif) ligand; CCR: C-C chemokine receptor; Dex: dexamethasone; ELISA: enzyme-linked immunosorbent assay; IFN: interferon; Ig: immunoglobulin; IL: interleukin; OVA: ovalbumin; PS: prednisolone; SDE: silkworm dropping extract; Th: T helper; TMA: trimellitic anhydride; TNF: tumor necrosis factor.

Fexofenadine Suppresses Delayed-Type Hypersensitivity in the Murine Model of Palladium Allergy

Palladium is frequently used in dental materials, and sometimes causes metal allergy. It has been suggested that the immune response by palladium-specific T cells may be responsible for the pathogenesis of delayed-type hypersensitivity in study of palladium allergic model mice. In the clinical setting, glucocorticoids and antihistamine drugs are commonly used for treatment of contact dermatitis. However, the precise mechanism of immune suppression in palladium allergy remains unknown. We investigated inhibition of the immune response in palladium allergic mice by administration of prednisolone as a glucocorticoid and fexofenadine hydrochloride as an antihistamine. Compared with glucocorticoids, fexofenadine hydrochloride significantly suppressed the number of T cells by interfering with the development of antigen-presenting cells from the sensitization phase. Our results suggest that antihistamine has a beneficial effect on the treatment of palladium allergy compared to glucocorticoids.

Betamethasone, but Not Tacrolimus, Suppresses the Development of Th2 Cells Mediated by Langerhans Cell-Like Dendritic Cells

It is well known that Langerhans cells (LCs) work as the primary orchestrators in the polarization of the immune milieu towards a T helper type 1 (Th1) or T helper type 2 (Th2) response. In this study, we investigated the effects of tacrolimus and betamethasone, each used as topical applications in atopic dermatitis (AD), on Th2 cell development mediated by LCs. LC-like dendritic cells (LDCs) were generated from mouse bone marrow cells and used as substitutes for LCs. Mice were primed with ovalbumin (OVA) peptide-pulsed LDCs, which had been treated with tacrolimus or betamethasone, via the hind footpad. After 5 d, the cytokine response in the popliteal lymph nodes was investigated by enzyme-linked immunosorbent assay. The expression of cell surface molecules on LDCs was investigated via reverse transcriptase polymerase chain reaction. Administration of OVA peptide-pulsed LDCs, which had been treated with betamethasone, inhibited Th2 cell development, as represented by the down-regulation of interleukin-4 production, and also inhibited Th1 cell development, represented by the down-regulation of interferon-γ production. However, tacrolimus-treated LDCs did not induce such inhibition of the development of Th1 and Th2 cells. The inhibition of Th1 and Th2 cell development was associated with the suppression of CD40 and T-cell immunoglobulin, and mucin domain-containing protein (TIM)-4 expression, respectively, in LDCs. These results suggest that the topical application of betamethasone to skin lesions of patients with AD acts on epidermal LCs, and may inhibit the development of Th2 cells, thus being of benefit for the control of AD.

Comparison of the effects of levocetirizine and losartan on diabetic nephropathy and vascular dysfunction in streptozotocin-induced diabetic rats

This work was designed to investigate the effects of levocetirizine, a histamine H1 receptor antagonist, on diabetes-induced nephropathy and vascular disorder, in comparison to an angiotensin II receptor antagonist, losartan. Diabetes was induced in male Sprague Dawley rats by a single intraperitoneal injection of streptozotocin (50mg/kg). Diabetic rats were divided into three groups; diabetic, diabetic-levocetirizine (0.5mg/kg/day) and diabetic-losartan (25mg/kg/day). Treatments were started two weeks following diabetes induction and continued for additional eight weeks. At the end of the experiment, urine was collected and serum was separated for biochemical measurements. Tissue homogenates of kidney and aorta were prepared for measuring oxidative stress, nitric oxide (NO), transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α). Moreover, histological analyses were conducted and aortic vascular reactivity was investigated. Levocetirizine improved renal function in diabetic rats (evidenced by mitigation of diabetes-induced changes in kidney to body weight ratio, serum albumin, urinary proteins and creatinine clearance). Moreover, levocetirizine attenuated the elevated renal levels of TNF-α and TGF-β1, ameliorated renal oxidative stress and restored NO bioavailability in diabetic kidney. These effects were comparable to or surpassed those produced by losartan. Moreover, levocetirizine, similar to losartan, reduced the enhanced responsiveness of diabetic aorta to phenylephrine. Histological evaluation of renal and aortic tissues further confirmed the beneficial effects of levocetirizine on diabetic nephropathy and revealed a greater attenuation of diabetes-induced vascular hypertrophy by levocetirizine than by losartan. In conclusion, levocetirizine may offer comparable renoprotective effect to, and possibly superior vasculoprotective effects than, losartan in streptozotocin-diabetic rats.

Drug-induced liver injury: Interactions between drug properties and host factors

Idiosyncratic drug-induced liver injury (DILI) is a common cause for drug withdrawal from the market and although infrequent, DILI can result in serious clinical outcomes including acute liver failure and the need for liver transplantation. Eliminating the iatrogenic "harm" caused by a therapeutic intent is a priority in patient care. However, identifying culprit drugs and individuals at risk for DILI remains challenging. Apart from genetic factors predisposing individuals at risk, the role of the drugs' physicochemical and toxicological properties and their interactions with host and environmental factors need to be considered. The influence of these factors on mechanisms involved in DILI is multi-layered. In this review, we summarize current knowledge on 1) drug properties associated with hepatotoxicity, 2) host factors considered to modify an individuals' risk for DILI and clinical phenotypes, and 3) drug-host interactions. We aim at clarifying knowledge gaps needed to be filled in as to improve risk stratification in patient care. We therefore broadly discuss relevant areas of future research. Emerging insight will stimulate new investigational approaches to facilitate the discovery of clinical DILI risk modifiers in the context of disease complexity and associated interactions with drug properties, and hence will be able to move towards safety personalized medicine.

Langerhans cell-like dendritic cells stimulated with an adjuvant direct the development of Th1 and Th2 cells in vivo

It is well known that Langerhans cells (LCs) work as the primary orchestrators in the polarization of immune responses towards a T helper type 1 (Th1) or Th2 milieu. In this study, we attempted to generate LCs from murine bone marrow cells and elicit a Th1- or Th2-prone immune response through the LCs after stimulation with Th1 or Th2 adjuvant. LCs were generated from murine bone marrow cells using granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-4 and transforming growth factor (TGF)-β, and were obtained as I-A(d) positive cells. Mice were primed with Th1/Th2 adjuvant- and ovalbumin (OVA)-pulsed LCs and then given a booster injection of OVA 2 days later via the hind footpad. Five days after the OVA injection, the cytokine response in the draining popliteal lymph nodes was investigated by reverse transcription-polymerase chain reaction (RT-PCR) flow cytometry and enzyme-linked immunosorbent assay (ELISA). The generated LCs expressed typical LC surface markers, E-cadherin and Langerin, and were classified accordingly as LC-like dendritic cells (LDCs). Administration of Th1 adjuvant, cytosine-phosphate-guanosine (CpG)-DNA- and OVA-pulsed LDCs into the hind footpads of mice induced a Th1-prone immune response, as represented by up-regulation of IFN-γ production and down-regulation of IL-4 production in the lymph node cells. Conversely, Th2 adjuvant, histamine-pulsed LDCs induced a Th2-prone immune response, as represented by up-regulation of IL-4 production and down-regulation of IFN-γ production. These results suggest that LDCs may be used as a substitute for LCs and have the ability to induce the development of Th1 and Th2 cells in vivo. Our experimental system would therefore be useful for screening of inhibitors of Th1/Th2 differentiation in order to control allergic disease.

Comedications alter drug-induced liver injury reporting frequency: Data mining in the WHO VigiBase™

Polypharmacy is common, and may modify mechanisms of drug-induced liver injury. We examined the effect of these drug-drug interactions on liver safety reports of four drugs highly associated with hepatotoxicity. In the WHO VigiBase™, liver event reports were examined for acetaminophen, isoniazid, valproic acid, and amoxicillin/clavulanic acid. Then, we evaluated the liver event reporting frequency of these 4 drugs in the presence of co-reported medications. Each of the 4 primary drugs was reported as having more than 2000 liver events, and co-reported with more than 600 different medications. Overall, the effect of 2275 co-reported drugs (316 drug classes) on the reporting frequency was analyzed. Decreased liver event reporting frequency was associated with 245 drugs/122 drug classes, including anti-TNFα, opioids, and folic acid. Increased liver event reporting frequency was associated with 170 drugs/82 drug classes; in particular, halogenated hydrocarbons, carboxamides, and bile acid sequestrants. After adjusting for age, gender, and other co-reported drug classes, multiple co-reported drug classes were significantly associated with decreased/increased liver event reporting frequency in a drug-specific/unspecific manner. In conclusion, co-reported medications were associated with changes in the liver event reporting frequency of drugs commonly associated with hepatotoxicity, suggesting that comedications may modify drug hepatic safety.

Anti-allergic and anti-inflammatory properties of a potent histamine H1 receptor antagonist, desloratadine citrate disodium injection, and its anti-inflammatory mechanism on EA.hy926 endothelial cells

The present study, demonstrates that, desloratadine citrate disodium injection (DLC) possesses antihistaminic, anti-allergic and anti-inflammatory properties and elucidates its molecular mechanisms of anti-inflammatory properties. In vitro antihistamine activity of DLC was determined in guinea pig isolated tissues. In vivo antihistamine effects were evaluated after following intravenous administration of DLC in mice with histamine- induced paw edema and in rats with increased capillary permeability. Anti-allergic effects were assessed through passive cutaneous anaphylactic (PCA) reactions in sensitized rodents and ovalbumin-induced allergic rhinitis in rats. Anti-inflammatory properties and molecular mechanisms of DLC were determined on histamine- and lipopolysaccharide (LPS)-induced EA.hy926 endothelial cells. DLC exhibited significant and reversible inhibition of histamine-induced contractions of isolated guinea pig ileum with pA2 value of 8.88. Histamine-induced paw edema and increased capillary permeability were notably inhibited by DLC intravenous administration. In the model of PCA reactions, DLC showed significant activity in a dose-dependent nd potently inhibited both the early-phase and late-phase allergic reaction of ovalbumin-induced allergic rhinitis in rats. DLC alleviated the rhinitis symptoms and inhibited inflammatory cell infiltration, IL-4 and protein leakage in nasal lavage fluid (NLF). In EA.hy926 cells, DLC significantly inhibited the histamine- and LPS- induced IL-6 and IL-8 production and P-selectin and intercellular cell adhesion molecule-1 (ICAM-1) expression. Moreover, DLC reduced translocation of nuclear factor-kappaB (NF-κB) to the nucleus in activated EA.hy926 cells. These results provide evidence that DLC possesses potent antihistaminic, anti-allergic and, anti-inflammatory properties via suppressing IL-6, IL-8, P-selectin and ICAM-1 expression.

Histamine H4 receptor ligands: future applications and state of art

Histamine is a chemical transmitter found practically in whole organism and exerts its effects through the interaction with H1 to H4 histaminergic receptors. Specifically, H4 receptors are found mainly in immune cells and blood-forming tissues, thus are involved in inflammatory and immune processes, as well as some actions in central nervous system. Therefore, H4 receptor ligands can have applications in the treatment of chronic inflammatory and immune diseases and may be novel therapeutic option in these conditions. Several H4 receptor ligands have been described from early 2000's until nowadays, being imidazole, indolecarboxamide, 2-aminopyrimidine, quinazoline, and quinoxaline scaffolds the most explored and discussed in this review. Moreover, several studies of molecular modeling using homology models of H4 receptor and QSAR data of the ligands are summarized. The increasing and promising therapeutic applications are leading these compounds to clinical trials, which probably will be part of the next generation of blockbuster drugs.

Comparison of airway responses in sheep of different age in precision-cut lung slices (PCLS)

Background

Animal models should display important characteristics of the human disease. Sheep have been considered particularly useful to study allergic airway responses to common natural antigens causing human asthma. A rationale of this study was to establish a model of ovine precision-cut lung slices (PCLS) for the in vitro measurement of airway responses in newborn and adult animals. We hypothesized that differences in airway reactivity in sheep are present at different ages.

Methods

Lambs were delivered spontaneously at term (147d) and adult sheep lived till 18 months. Viability of PCLS was confirmed by the MTT-test. To study airway provocations cumulative concentration-response curves were performed with different allergic response mediators and biogenic amines. In addition, electric field stimulation, passive sensitization with house dust mite (HDM) and mast cells staining were evaluated.

Results

PCLS from sheep were viable for at least three days. PCLS of newborn and adult sheep responded equally strong to methacholine and endothelin-1. The responses to serotonin, leukotriene D₄ and U46619 differed with age. No airway contraction was evoked by histamine, except after cimetidine pretreatment. In response to EFS, airways in PCLS from adult and newborn sheep strongly contracted and these contractions were atropine sensitive. Passive sensitization with HDM evoked a weak early allergic response in PCLS from adult and newborn sheep, which notably was prolonged in airways from adult sheep. Only few mast cells were found in the lungs of non-sensitized sheep at both ages.

Conclusion

PCLS from sheep lungs represent a useful tool to study pharmacological airway responses for at least three days. Sheep seem well suited to study mechanisms of cholinergic airway contraction. The notable differences between newborn and adult sheep demonstrate the importance of age in such studies.

Rupatadine protects against pulmonary fibrosis by attenuating PAF-mediated senescence in rodents

A similar immune response is implicated in the pathogenesis of pulmonary fibrosis and allergic disorders. We investigated the potential therapeutic efficacy and mechanism of rupatadine, a dual antagonist of histamine and platelet-activation factor (PAF), in bleomycin- (BLM-) and silica-induced pulmonary fibrosis. The indicated dosages of rupatadine were administered in rodents with bleomycin or silica-induced pulmonary fibrosis. The tissue injury, fibrosis, inflammatory cells and cytokines, and lung function were examined to evaluate the therapeutic efficacy of rupatadine. The anti-fibrosis effect of rupatadine was compared with an H1 or PAF receptor antagonist, and efforts were made to reveal rupatadine’s anti-fibrotic mechanism. Rupatadine promoted the resolution of pulmonary inflammation and fibrosis in a dose-dependent manner, as indicated by the reductions in inflammation score, collagen deposition and epithelial-mesenchymal transformation, and infiltration or expression of inflammatory cells or cytokines in the fibrotic lung tissue. Thus, rupatadine treatment improved the declined lung function and significantly decreased animal death. Moreover, rupatadine was able not only to attenuate silica-induced silicosis but also to produce a superior therapeutic efficacy compared to pirfenidone, histamine H1 antagonist loratadine, or PAF antagonist CV-3988. The anti-fibrotic action of rupatadine might relate to its attenuation of BLM- or PAF-induced premature senescence because rupatadine treatment protected against the in vivo and in vitro activation of the p53/p21-dependent senescence pathway. Our studies indicate that rupatadine promotes the resolution of pulmonary inflammation and fibrosis by attenuating the PAF-mediated senescence response. Rupatadine holds promise as a novel drug to treat the devastating disease of pulmonary fibrosis.

Biological toxicity and inflammatory response of semi-single-walled carbon nanotubes

The toxicological studies on carbon nanotubes (CNTs) have been urgently needed from the emerging diverse applications of CNTs. Physicochemical properties such as shape, diameter, conductance, surface charge and surface chemistry of CNTs gained during manufacturing processes play a key role in the toxicity. In this study, we separated the semi-conductive components of SWCNTs (semi-SWCNTs) and evaluated the toxicity on days 1, 7, 14 and 28 after intratracheal instillation in order to determine the role of conductance. Exposure to semi-SWCNTs significantly increased the growth of mice and significantly decreased the relative ratio of brain weight to body weight. Recruitment of monocytes into the bloodstream increased in a time-dependent manner, and significant hematological changes were observed 28 days after exposure. In the bronchoalveolar lavage (BAL) fluid, secretion of Th2-type cytokines, particularly IL-10, was more predominant than Th1-type cytokines, and expression of regulated on activation normal T cell expressed and secreted (RANTES), p53, transforming growth factor (TGF)-β, and inducible nitric oxide synthase (iNOS) increased in a time-dependent manner. Fibrotic histopathological changes peaked on day 7 and decreased 14 days after exposure. Expression of cyclooxygenase-2 (COX-2), mesothelin, and phosphorylated signal transducer and activator of transcription 3 (pSTAT3) also peaked on day 7, while that of TGF-β peaked on days 7 and 14. Secretion of histamine in BAL fluid decreased in a time-dependent manner. Consequently, we suggest that the brain is the target organ of semi-SWCNTs brought into the lung, and conductance as well as length may be critical factors affecting the intensity and duration of the inflammatory response following SWCNT exposure.

Combination treatment of mice with CRx-153 (nortriptyline and desloratadine) decreases the severity of experimental autoimmune encephalomyelitis

Pro-inflammatory CD4(+) T cell-mediated autoimmune diseases, such as multiple sclerosis, are hypothesized to be initiated and maintained by self-reactive interferon-gamma (IFN-γ) and interleukin-17 (IL-17) producing CD4(+) T cells. Previous studies have shown moderate to significant alterations in inflammatory T cell responses and potentially treatment of autoimmune disease by administration of antihistamine or tricyclic antidepressants alone. The goal of the present study was to determine if treatment of PLP(139-151)-induced relapsing-remitting experimental autoimmune encephalomyelitis (R-EAE) in SJL/J mice with a combination of two FDA approved drugs for other indications could decrease R-EAE disease. The findings show that combination treatment with desloratadine and nortriptyline decreases the mean clinical score, disease relapse frequency, and number of CD4(+) T cells infiltrating into the CNS. In addition, combination treatment of PLP(139-151) primed mice decreases the level of IFN-γ and IL-17 secreted via a decrease in both the number of cells secreting and the amount of cytokine secreted per cell following PLP(139-151) reactivation ex vivo. This is in contrast to an increase in the level of IL-4 produced and the number of IL-4 secreting cells. The data also show that combination treatment with desloratadine and nortriptyline inhibits the production of IFN-γ and IL-17 produced by naive CD4(+) T cells activated in the presence of Th1 cell- and Th17 cell-promoting conditions, while increasing the level of IL-4 produced by naive CD4(+) T cells activated in the presence of Th2 cell-promoting conditions. The present findings suggest a novel method for the development of a putative autoimmune therapy.

Histamine and histamine receptors in pathogenesis and treatment of multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease associated with chronic inflammatory demyelination of the central nervous system (CNS). Due to disease complexity and heterogeneity, its pathogenesis remains unknown and despite extensive studies, specific effective treatments have not yet been developed. The factors behind the initiation of the inflammatory reactions in CNS have not been identified until now. MS is considered as a complex disease depending on genetic as well as environmental factors. Experimental autoimmune encephalomyelitis (EAE) is the preferential experimental rodent model for MS. Histamine [2-(4-imidazole) ethylamine] is a ubiquitous inflammatory mediator of diverse physiological processes including neurotransmission, secretion of pituitary hormones, and regulation of the gastrointestinal and circulatory systems which can modulate immune responses. Histamine functions are mediated through four G-protein coupled receptors that are named H1-H4 receptor. Histamine is implicated as an important factor in pathophysiology of MS and EAE. It has been shown that histamine can change the permeability of blood brain barrier, which leads to elevation of infiltrated cells in CNS and neuroinflammation. In contrast, there are evidence that show the protective role of histamine in MS and its animal model, EAE. In this review, we try to clarify the role of histamine in pathogenesis of MS, as well as we evaluate the efficacy of histamine receptors agonists and antagonists in treatment of this disease.

Histamine induces Th2 activation through the histamine receptor 1 in house dust mite rhinitic but not asthmatic patients

BACKGROUND

Effects of mast cell-released histamine on smooth muscle and endothelial cells are considered as responsible of immediate symptoms of anaphylaxis. However, little is known about histamine effects on Th2 lymphocytes, which orchestrate the allergic reaction upstream of mast cells.

OBJECTIVE

We addressed this question in house dust mite (HDM) allergics, according to the presence of rhinitis or asthma and allergen stimulation.

METHODS

Peripheral blood mononuclear cell from 15 rhinitic and 14 asthmatic HDM-allergic subjects and 16 controls were cultured with Der p 1 or histamine. The effect of Der p 1 on histamine receptor (H1R and H2R) expression was studied. T-cell cytokine production was studied upon Der p 1 or histamine stimulation. The role of H1R in histamine effects was assessed with levocetirizine.

RESULTS

H1R and H2R are overexpressed on T cells from asthmatic but not from rhinitic subjects. Der p 1 increases H1R expression on CD4(+) cells from both allergic groups, and decreases it in controls, on CD4(+) and CD8(+) subsets. Der p 1 decreases T-cell H2R expression in asthmatics. Allergen increases IL-4 and IL-13 in both allergic groups. Histamine increases Th2 cytokines in rhinitics only, and levocetirizine abolishes this effect. In asthmatics and controls, histamine decreases T-cell cytokines through a non-H1R dependent pathway.

CONCLUSION

In rhinitis but not in asthma, histamine is able to increase allergic inflammation by increasing Th2 cytokine production in a positive feedback dependent on H1R. This result could explain in part why H1R antagonists, are very efficient in rhinitis, but not in asthma.

Inter-Relationship between Chemokines and Mast Cells

The inflammatory response is mediated by immunological and chemotactic factors, proteins of the complement system, histamine, serotonin, arachidonic acid products and cytokines. All these compounds, including cytokines/chemokines, are major contributors to the symptoms of inflammation. Cytokines/chemokines, commonly referred to as “biological response modifiers”, are relatively new compounds for possible use in stimulation of the immune response, and display a number of overlapping abilities to stimulate cells of various lineages and differentiation stages; nonetheless, most of these compounds are potent inflammatory mediators. Mast cell mediators are either contained within secretory granules or can be synthesized de novo and can be released upon activation by either a massive degranulation, or by a selective release of specific molecules. These cells accumulate in the stroma of a variety of inflamed and transformed tissues in response to locally produced chemotactic factors for immune-cells, such as RANTES and MCP-1. Here we describe some connections between mast cells and chemokines.