Quantification of Pancreatic Islets: Using Image Analysis Tools.

Histological image analysis is becoming an increasingly important tool for research in biological science. They are important in analyzing biological systems on various scales, from structural details to determination of number of cells, its area, localization, and concentration. This chapter focuses on analysis of pancreatic sections stained for insulin and glucagon using a commercially available software.

Collagen remodeling and peripheral immune cell recruitment characterizes the cutaneous Langerhans cell histiocytosis microenvironment.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare and potentially fatal disorder of unknown etiology arising from the accumulation of epidermal Langerhans-like cells in bone, skin, or other tissues. Tissue damage and morbidity results from lesional cytokine release, and we sought to investigate the LCH microenvironment using a combination of histological stains and immunohistochemistry. METHODS: CD1a immunoreactivity was used to identify lesional cells in archival paraffin-embedded samples of cutaneous LCH. A combined Orcein and Giemsa stain identified immune cells in general (particularly granulocytes and mast cells) and extracellular matrix (particularly elastic fibers), while CD3 and CD68 staining identified T cells and macrophages, respectively. Collagen synthesis was investigated with Herovici staining, which discriminates newly synthesized from mature collagen, while cross-polar microscopy of picrosirius-stained sections identified changes in matrix organization. RESULTS: Immune cells were consistently identified at the periphery of cutaneous LCH lesions. We quantified an increased number of thickened and disorganized elastic fibers surrounding lesions and an absence of elastic fibers within lesions. Furthermore, lesions exhibited a decrease in mature collagen fibers and a loss of supporting collagen matrix within lesions and compromised collagen integrity in adjacent tissue. CONCLUSIONS: Cutaneous LCH lesions are associated with the peripheral recruitment of a variety of immune cells and are consistently characterized by localized elastosis, collagen damage, and remodeling.

A novel method to assess collagen architecture in skin.

BACKGROUND: Texture within biological specimens may reveal critical insights, while being very difficult to quantify. This is a particular problem in histological analysis. For example, cross-polar images of picrosirius stained skin reveal exquisite structure, allowing changes in the basketweave conformation of healthy collagen to be assessed. Existing techniques measure gross pathological changes, such as fibrosis, but are not sufficiently sensitive to detect more subtle and progressive pathological changes in the dermis, such as those seen in ageing. Moreover, screening methods for cutaneous therapeutics require accurate, unsupervised and high-throughput image analysis techniques. RESULTS: By analyzing spectra of images post Gabor filtering and Fast Fourier Transform, we were able to measure subtle changes in collagen fibre orientation intractable to existing techniques. We detected the progressive loss of collagen basketweave structure in a series of chronologically aged skin samples, as well as in skin derived from a model of type 2 diabetes mellitus. CONCLUSIONS: We describe a novel bioimaging approach with implications for the evaluation of pathology in a broader range of biological situations.