House dust mite-induced asthma exacerbates Alzheimer's disease changes in the brain of the AppNL-G-F mouse model of disease.

Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by the accumulation of amyloid-ß (Aß) plaques, neuroinflammation, and neuronal death. Besides aging, various comorbidities increase the risk of AD, including obesity, diabetes, and allergic asthma. Epidemiological studies have reported a 2.17-fold higher risk of dementia in asthmatic patients. However, the molecular mechanism(s) underlying this asthma-associated AD exacerbation is unknown. This study was designed to explore house dust mite (HDM)-induced asthma effects on AD-related brain changes using the AppNL-G-F transgenic mouse model of disease. Male and female 8-9 months old C57BL/6J wild type and AppNL-G-F mice were exposed to no treatment, saline sham, or HDM extract every alternate day for 16 weeks for comparison across genotypes and treatment. Mice were euthanized at the end of the experiment, and broncho-alveolar lavage fluid (BALF), blood, lungs, and brains were collected. BALF was used to quantify immune cell phenotype, cytokine levels, total protein content, lactate dehydrogenase (LDH) activity, and total IgE. Lungs were sectioned and stained with hematoxylin and eosin, Alcian blue, and Masson's trichrome. Serum levels of cytokines and soluble Aß1-40/42 were quantified. Brains were sectioned and immunostained for Aß, GFAP, CD68, and collagen IV. Finally, frozen hippocampi and temporal cortices were used to perform Aß ELISAs and cytokine arrays, respectively. HDM exposure led to increased levels of inflammatory cells, cytokines, total protein content, LDH activity, and total IgE in the BALF, as well as increased pulmonary mucus and collagen staining in both sexes and genotypes. Levels of serum cytokines increased in all HDM-exposed groups. Serum from the AppNL-G-F HDM-induced asthma group also had significantly increased soluble Aß1-42 levels in both sexes. In agreement with this peripheral change, hippocampi from asthma-induced male and female AppNL-G-F mice demonstrated elevated Aß plaque load and increased soluble Aß 1-40/42 and insoluble Aß 1-40 levels. HDM exposure also increased astrogliosis and microgliosis in both sexes of AppNL-G-F mice, as indicated by GFAP and CD68 immunoreactivity, respectively. Additionally, HDM exposure elevated cortical levels of several cytokines in both sexes and genotypes. Finally, HDM-exposed groups also showed a disturbed blood-brain-barrier (BBB) integrity in the hippocampus of AppNL-G-F mice, as indicated by decreased collagen IV immunoreactivity. HDM exposure was responsible for an asthma-like condition in the lungs that exacerbated Aß pathology, astrogliosis, microgliosis, and cytokine changes in the brains of male and female AppNL-G-F mice that correlated with reduced BBB integrity. Defining mechanisms of asthma effects on the brain may identify novel therapeutic targets for asthma and AD.

Salicylic acid derivatives as potential anti asthmatic agents using disease responsive drug delivery system for prophylactic therapy of allergic asthma.

Asthma is a multi-factorial and complicated lung disorder of the immune system which has expanded to a wider ambit unveiling its etiology to be omnipresent at both ends of the spectrum involving basic pharmacology and in-depth immunology. As asthma occurs through triggered activation of various immune cells due to different stimuli, it poses a great challenge to uncover specific targets for therapeutic interventions. Recent pharmacotherapeutic approaches for asthma have been focused on molecular targeting of transcription factors and their signaling pathways; mainly nucleus factor kappa B (NFκB) and its associated pathways which orchestrate the synthesis of pro-inflammatory cytokines (IL-1ß, TNF-α, GM-CSF), chemokines (RANTES, MIP-1a, eotaxin), adhesion molecules (ICAM-1, VCAM-1) and inflammatory enzymes (cyclooxygenase-2 and iNOS). 5-aminosalicylic acid (5-ASA) and sodium salicylate are known to suppress NFκB activation by inhibiting inhibitor of kappa B kinase (IKκB). In order to target the transcription factor, a suitable carrier system for delivering the drug to the intracellular space is essential. 5-ASA and sodium salicylate loaded liposomes incorporated into PEG-4-acrylate and CCRGGC microgels (a polymer formed by crosslinking of trypsin sensitive peptide and PEG-4-acrylate) could probably suit the needs for developing a disease responsive drug delivery system which will serve as a prophylactic therapy for asthmatic patients.

5-Aminosalicylic acid attenuates allergen-induced airway inflammation and oxidative stress in asthma.

Pro-inflammatory cytokines regulate the magnitude of allergic reactions during asthma. Tumor necrosis factor--alpha (TNF-α), interleukin-6 (IL-6) and interleukin-13 (IL-13) play a crucial role in aggravating the inflammatory conditions during allergic asthma. In addition, oxidative stress contributes to the pathogenesis of asthma by altering the physiological condition resulting in the development of status asthmaticus. Anti-inflammatory corticosteroids are being widely used for treating allergic asthma. In the present study 5-aminosalicylic acid (5-ASA), a salicylic acid derivative, was evaluated, in vivo for its potential to suppress TNF-α, IL-6 and IL-13 using ovalbumin (OVA) induced allergic asthma in Balb/C mice. Oral administration of 65, 130 and 195 mg/kg 5-ASA significantly reduced the OVA induced total and differential leucocyte count, TNF-α, IL-6, IL-13, nitrite, nitrate, MDA, MPO and TPL levels in the lung lavage samples. Collectively, these findings suggest that 5-ASA is a potent immunomodulator and suppresses key Th2 cytokines production and oxidative stress in OVA-induced asthma.