Characterisation of the proximal airway squamous metaplasia induced by chronic tobacco smoke exposure in spontaneously hypertensive rats

<p>Abstract</p> <p>Background</p> <p>Continuous exposure to tobacco smoke (TS) is a key cause of chronic obstructive pulmonary disease (COPD), a complex multifactorial disease that is difficult to model in rodents. The spontaneously hypertensive (SH) rat exhibits several COPD-associated co-morbidities such as hypertension and increased coagulation. We have investigated whether SH rats are a more appropriate animal paradigm of COPD.</p> <p>Methods</p> <p>SH rats were exposed to TS for 6 hours/day, 3 days/week for 14 weeks, and the lung tissues examined by immunohistochemistry.</p> <p>Results</p> <p>TS induced a CK13-positive squamous metaplasia in proximal airways, which also stained for Ki67 and p63. We hypothesise that this lesion arises by basal cell proliferation, which differentiates to a squamous cell phenotype. Differences in staining profiles for the functional markers CC10 and surfactant D, but not phospho-p38, indicated loss of ability to function appropriately as secretory cells. Within the parenchyma, there were also differences in the staining profiles for CC10 and surfactant D, indicating a possible attempt to compensate for losses in proximal airways. In human COPD sections, areas of CK13-positive squamous metaplasia showed sporadic p63 staining, suggesting that unlike the rat, this is not a basal cell-driven lesion.</p> <p>Conclusion</p> <p>This study demonstrates that although proximal airway metaplasia in rat and human are both CK13+ and therefore squamous, they potentially arise by different mechanisms.</p

Identification of platform-independent gene expression markers of cisplatin nephrotoxicity.

Within the International Life Sciences Institute Committee on Genomics, a working group was formed to focus on the application of microarray technology to preclinical assessments of drug-induced nephrotoxicity. As part of this effort, Sprague-Dawley rats were treated with the nephrotoxicant cisplatin at doses of 0.3-5 mg/kg over a 4- to 144-hr time course. RNA prepared from these animals was run on a variety of microarray formats at multiple sites. A set of 93 differentially expressed genes associated with cisplatin-induced renal injury was identified on the National Institute of Environmental Health Sciences (NIEHS) custom cDNA microarray platform using quadruplicate measurements of pooled animal RNA. The reproducibility of this profile of statistically significant gene changes on other platforms, in pooled and individual animal replicate samples, and in an independent study was investigated. A good correlation in response between platforms was found among the 48 genes in the NIEHS data set that could be matched to probes on the Affymetrix RGU34A array by UniGene identifier or sequence alignment. Similar results were obtained with genes that could be linked between the NIEHS and Incyte or PHASE-1 arrays. The degree of renal damage induced by cisplatin in individual animals was commensurate with the number of differentially expressed genes in this data set. These results suggest that gene profiles linked to specific types of tissue injury or mechanisms of toxicity and identified in well-performed replicated microarray experiments may be extrapolatable across platform technologies, laboratories, and in-life studies

A novel application for Cocoacrisp protein as a biomarker for experimental pulmonary fibrosis

Pulmonary fibrosis is a debilitating disease affecting up to 2 million people worldwide, with a median survival rate of only 3 years after diagnosis. The aim of this study was to evaluate a potential protein biomarker (Cocoacrisp, CC) to identify the onset of pulmonary fibrosis. A model of fibrosis was induced via intratracheal instillation of bleomycin, and samples were collected during the early phase of the disease. Immunohistochemical identification of CC was carried out in lung tissue from the bleomycin model. Quantification by image analysis showed CC levels were doubled (p <0.0003), after a single bleomycin dose, but not after double instillation. Microscopic analysis revealed that CC signal was primarily detected on the alveolar surface. The secretion of the novel protein CC during the early stages of bleomycin-induced injury may have the potential to be utilized as a clinical biomarker for the early stages of fibrosis, particularly as it may be detectable in bronchoalveolar lavage fluid

Osteogenesis on surface selective laser sintered bioresorbable scaffolds

In this study we have used a novel surface selective laser sintering (SSLS) technique to develop CAD/CAM designed scaffolds for bone tissue engineering. SSLS polylactic acid scaffolds were evaluated in vitro and in vivo as templates for human fetal femur-derived cell and adult human bone marrow stromal cell osteogenesis. Both cell types were cultured successfully on SSLS scaffolds with an increase in expression of alkaline phosphatase activity. Cell in-growth and Alcian blue/Sirius red positive staining of matrix deposition were observed on SSLS scaffolds in vitro in basal medium and osteogenic culture conditions. Similar results were observed in vivo with type I collagen expressed by cells on the scaffolds. In the critical sized femur segmental defect, SSLS scaffolds seeded with the cells enhanced significantly bone tissue regeneratio

Biocompatibility and osteogenic potential of human fetal femur-derived cells on surface selective laser sintered scaffolds

For optimal bone regeneration, scaffolds need to fit anatomically into the requisite bone defects and, ideally, augment cell growth and differentiation. In this study we evaluated novel computationally designed surface selective laser sintering (SSLS) scaffolds for their biocompatibility as templates, in vitro and in vivo, for human fetal femur-derived cell viability, growth and osteogenesis. Fetal femur-derived cells were successfully cultured on SSLS-poly(d,l)-lactic acid (SSLS-PLA) scaffolds expressing alkaline phosphatase activity after 7 days. Cell proliferation, ingrowth, Alcian blue/Sirius red and type I collagen positive staining of matrix deposition were observed for fetal femur-derived cells cultured on SSLS-PLA scaffolds in vitro and in vivo. SSLS-PLA scaffolds and SSLS-PLA scaffolds seeded with fetal femur-derived cells implanted into a murine critical-sized femur segmental defect model aided the regeneration of the bone defect. SSLS techniques allow fabrication of biocompatible/biodegradable scaffolds, computationally designed to fit any defect, providing a template for cell osteogenesis in vitro and in vivo

Identification of platform-independent gene expression markers of cisplatin nephrotoxicity.

Within the International Life Sciences Institute Committee on Genomics, a working group was formed to focus on the application of microarray technology to preclinical assessments of drug-induced nephrotoxicity. As part of this effort, Sprague-Dawley rats were treated with the nephrotoxicant cisplatin at doses of 0.3-5 mg/kg over a 4- to 144-hr time course. RNA prepared from these animals was run on a variety of microarray formats at multiple sites. A set of 93 differentially expressed genes associated with cisplatin-induced renal injury was identified on the National Institute of Environmental Health Sciences (NIEHS) custom cDNA microarray platform using quadruplicate measurements of pooled animal RNA. The reproducibility of this profile of statistically significant gene changes on other platforms, in pooled and individual animal replicate samples, and in an independent study was investigated. A good correlation in response between platforms was found among the 48 genes in the NIEHS data set that could be matched to probes on the Affymetrix RGU34A array by UniGene identifier or sequence alignment. Similar results were obtained with genes that could be linked between the NIEHS and Incyte or PHASE-1 arrays. The degree of renal damage induced by cisplatin in individual animals was commensurate with the number of differentially expressed genes in this data set. These results suggest that gene profiles linked to specific types of tissue injury or mechanisms of toxicity and identified in well-performed replicated microarray experiments may be extrapolatable across platform technologies, laboratories, and in-life studies