Preclinical Models for Pulmonary Drug Delivery
Anthony J. Hickey, Sandro R.P. da Rocha in Pharmaceutical Inhalation Aerosol Technology, 2019
Despite gross similarities in respiratory anatomy across species, the differences in size, geometry, and position of these anatomical structures can have a significant impact on the outcome of respiratory drug studies. The respiratory system has two fundamental purposes: (1) to regulate respiration, oxygen transfer, and carbon dioxide removal and (2) to protect the lungs from foreign or noxious particle inhalation so that respiration remains uninterrupted. These two goals are supported by the basic anatomical structure of the airways, comprising the trachea, bronchi and bronchioles, and the terminal alveoli. The airways are lined by the mucosal respiratory epithelium, beneath which there is a complex cellular tissue makeup that varies in its composition along the respiratory tree, but which includes the underlying loose connective tissue of the submucosa that may comprise cartilage, neuronal and capillary networks, and interstitial cells such as airway smooth muscle, myofibroblasts, fibroblasts, and immune cells.
Traditional Medicinal Plants for Respiratory Diseases: Mexico
Megh R. Goyal, Durgesh Nandini Chauhan in Assessment of Medicinal Plants for Human Health, 2020
The traditional use of this plant in Mexico as well as other countries is for the treatment of bronchitis cough, laryngitis, pharyngitis, and tuberculosis. The whole plant is used to make a tea. The plant is rich in mucilage and various other phytochemicals including usnic acid. The mucilaginous components act as antitussives, diuretics, and demulcents. The latter effects are useful to protect the respiratory mucosa. The lichenic acids have an expectorant as well as antibacterial and antifungal action. Herbalists in Mexico recommend decocting the 10–15 g of the plant in 3 L (approximately 3 quarts) of water during 2–4 min at a low heat. The decoction is strained and taken 4 times per day for a period of 15–20 days. Ingested in high doses, the plant could be irritating to the stomach.34
Inflammation and immunology
C. Simon Herrington in Muir's Textbook of Pathology, 2020
The basic passive defences against infection are barrier tissues, which use non-specific physical and chemical strategies to prevent access of infectious agents into the body. The interface between body and environment is lined by epithelia, including the skin and linings of the gastrointestinal, respiratory and genitourinary tracts. These different epithelia consist of a continuous cohesive layer of cells, bound to each other and the underlying connective tissue by specialized junctions and cell adhesion molecules. The physical barrier is bolstered differently according to the site: keratin and multilayering make skin a tough, waterproof surface, while fatty acids from sebaceous glands maintain a hostile low pH on its surface. In the gastrointestinal tract there is secretion of acid in the stomach, digestive enzymes from the pancreas, and mucins produced by specialized cells throughout the tract. The respiratory epithelium secretes mucus to entrap bacteria, which are then expelled by the action of cilia on the cell surface. Urine from the kidney flushes the lower urinary tract.
Stevens Johnson syndrome: A review of a vision and life-threatening mucocutaneous disease including histopathology with updates on pathogenesis and genetic risk factors
Published in Seminars in Ophthalmology, 2021
Vamsee K. Neerukonda, Anna M. Stagner
Patients with SJS/TEN often endorse symptoms of a high-grade fever and/or a viral prodrome prior to the onset of mucocutaneous and systemic disease. Mucous membrane involvement, particularly of the ocular surface, precedes skin blistering by 1–5 days. Acute ocular involvement occurs in 50–88% of cases,69,77–82 and typically lasts 2–4 weeks. Among those who survive, chronic ocular sequelae develop in 20–79% of patients with symptoms ranging from dry eye syndrome to chronic inflammation, scarring and blindness.79,83–86 Concomitant erosion and ulceration of the buccal and genital mucosa is also common in the acute phase of disease. Less commonly involved mucosae include the respiratory epithelium in 27% of TEN patients87 and the gastrointestinal tract. SJS/TEN involvement by organ system is summarized in Table 3.
Silent sinus syndrome: combined sinus surgery and orbital reconstruction – report of 15 cases
Published in Acta Oto-Laryngologica, 2019
Pedro Clarós, Aleksandra Zofia Sobolewska, Antonio Cardesa, Marta Lopez-Fortuny, Andres Claros
In histology reports, signs of compression atrophy of sinus mucosa and muco-eosinophilic secretion were present. A cluster of apoptotic cells portraying pyknotic nuclei and granular eosinophilic cytoplasm were seen in high magnification. Also, atrophic sinonasal mucosa with extensive loss of the respiratory epithelium, thickened basal membrane and arterioles with markedly thickened walls could be distinguished (Figures 1 and 2). Atrophic sinonasal mucosa with preserved respiratory epithelium at the surface was also present. Hyaline thickening of the basement membrane, fibrosis and dilated capillary vessels of the lamina propria were common findings. Transversal section showed arterioles with thickened wall entrapping beneath the atrophic glands. Vertical spicule of atrophic bone was also noticed. Histological report highlights different signs of pressure atrophy, in some specimens with the apparent accompaniment of eosinophils.
Hyaluronan antagonizes the differentiation effect of TGF-β1 on nasal epithelial cells through down-regulation of TGF-β type I receptor
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Tsung-Wei Huang, Sheng-Tien Li, Kai-Min Fang, Tai-Horng Young
The mucociliary differentiation of NECs also had similar results. The mucociliary system, including ciliated respiratory epithelium, mucous blanket and periciliary fluid, serves as a major defence mechanism in the respiratory system. Restoration of mucociliary function is important in sinonasal surgery as well as in respiratory tract reconstruction. During the cascade of wound healing, TGF-β1 is an important signal for the initiation of the healing cascade by attracting macrophages and stimulates them to secrete additional cytokines. TGF-β1 further improves fibroblast and smooth muscle cell chemotaxis and modulates collagen and collagenase expression. However, TGF-β1 inhibits mucociliary differentiation of NECs and concentrations of TGF-β1 as low as 1 pM inhibit the growth of primary cultures of respiratory epithelial cells, which accumulate in the G0-G1 phases of the cell cycle and tend to become squamous with formation of cross-linked envelopes [27]. The results show that HA promote mucociliary differentiation of NECs, which is compatible with previous reports [8]. Additionally, mucociliary differentiation of NECs is inhibited by TGF-β1, and HA prevents the TGF-β1 effect on the differentiation of NECs.
Related Knowledge Centers
- Basement Membrane
- Epithelium
- Mucociliary Clearance
- Mucus
- Pharynx
- Pseudostratified Columnar Epithelium
- Respiratory Tract
- Stratified Squamous Epithelium
- Vocal Cords
- Larynx