REPROCELL is able to offer an extensive range of assays in fresh human lung tissue from healthy and diseased non-transplantable lungs or surgical residual tissues.
Such living human tissues allow REPROCELL to investigate the effects of drugs on the human respiratory systems in a number of ways including:
Effects on respiratory function are already required to be assessed as part of the ICH S7A core battery of tests prior to human exposure. REPROCELL’s respiratory assays allow the safety of your compound to be determined far in advance of the clinical development phase. Additionally, we are able to procure diseased tissues, making it possible to carry out detailed safety studies on different patient populations, making comparisons that would otherwise be impossible. REPROCELL’s assays provide the optimum model for research into a range of conditions, such as COPD and asthma.
Whole lungs and resections of lung obtained from surgery are available fresh and can be used in a range of experimental setups such as tissue baths (shown below), wire myographs, Ussing chambers and ex vivo cultures including precision-cut lung slices.
REPROCELL, under its Biopta brand pharmacology services, can investigate isolated fresh tissues from many regions of the lung, including upper airways, secondary or tertiary bronchi or parenchyma.
Using our organ bath or wire myographs for larger and smaller airways respectively, we are able to determine the bronchoconstrictive or bronchorelaxatory effects of a test compound in ex vivo human tissue. Figure 1 shows the effects of drugs on isolated rings of human bronchi; such studies can be conducted in large conducting airways or small bronchi, providing information on responses throughout the bronchial tree.
Only human test systems truly reflect the human responses to drugs, even the most commonly used animal models of respiratory function, the guinea pig, fails to replicate all human responses (see Table 1). Human airways respond similarly to histamine; however, the responses to acetylcholine are markedly different. Using human tissues avoids uncertainties in decision-making based on animal models.
|Species||pD2 acetylcholine||pD2 histamine|
|Human||4.56||5.31 ± 0.27|
|Guinea pig||5.89||5.31 ± 0.72|
Human and animal lung slices: a phenotypically-accurate functional assay system for screening and target validation
Precision-cut lung slices (PCLS) are increasingly in demand for the testing of xenobiotics, chemicals and cosmetics. By retaining both the structural and functional integrity of human or animal lungs, the method combines throughput with relevance, offering a phenotypically-accurate model of lung behaviour.
Moreover, Biopta’s unique access to healthy and diseased lung allows it to investigate drug effects in patients with COPD or asthma. Cross-species comparisons also allow the translation of preclinical animal data to the human situation to be assessed.
Precision-cut lung slices:
To discuss a precision cut lung slice study with Biopta please contact us.
Lung or tracheal epithelial tissue can be assessed in the Ussing Chamber to determine changes in short circuit current (Isc) after exposure to your test compound. This information is particularly valuable when assessing treatments for conditions like cystic fibrosis where fluid movement across airway epethelium is disrupted resulting in thick mucus production.
Biopta has conducted a range of studies investigating specific ion channels in human or animal tracheal mucosa. Intact mucosa is dissected free from the trachea or primary bronchui and set up in Ussing chambers for measurement of functional responses. Figure 1 below shows the responses of human tracheal epithelium to the presence of increasing concentrations of the sodium channel blocker, amiloride.
Through its extensive tissue network Biopta can obtain both healthy and diseased human lung samples for use in our range of ex vivo respiratory assays.
The parenchymal explant culture model provides an excellent platform to investigate and understand the mechanisms of lung diseases such as asthma and COPD. The model is also ideally suited for investigating the local effects of test compounds by being suitable for investigating a wide range of translational end points. The fresh explants contain the full complement of lung parenchymal cells in their native ratios and spacial orientation. This allows normal cell-cell communications and interactions to take place, replicating the local in vivo conditions of the lung.
An overview of the basic methodology is provided below in Figure 1.
Upon receipt, the tissue is dissected free from the pleural membrane. Visible airways and blood vessels are also removed to produce the parenchyma explants (3-5mm3). The parenchyma explants are then maintained in culture, under physiological conditions, where the test conditions can be added. The orientation of the explants in culture provides the opportunity to study a wide range of experimental endpoints including (but not limited to) the following; the release of biomarkers/ mediators (culture media), the effects of test compounds on explant viability (culture media/explant), histopathological changes (explant), gene expression changes (explant) and changes in cell signalling mechanisms (explant).
Shown below in figure 2 is mean data obtained from experiments using 4 COPD donor lung samples. The ability of a range of standard of care treatments to modulate TNFalpha release from LPS stimulated explants was investigated. The standard of care drugs tested were the PDE 4 inhibitor Roflumilast, the glucocorticoid Fluticasone and the beta 2-adrenoceptor agonist Formoterol. Each treatment was tested alone and in combination with the others.
Key benefits of Biopta’s human parenchymal explant model: