Non-invasive assessment of liver fibrosis in C282Y homozygous HFE hemochromatosis.

BACKGROUND & AIMS: C282Y homozygotes with serum ferritin (SF) levels >1000 µg/L and/or increased serum transaminase levels are at risk of severe F3/F4 fibrosis. Current practical guidelines recommend liver biopsy in such individuals. This prospective observational cohort study aimed to evaluate non-invasive alternative means such as hyaluronic acid (HA) and transient elastography (TE) for the assessment of severe fibrosis in patients with SF >1000 µg/L or elevated transaminases. METHODS: Between September 2005 and April 2013, 77 patients diagnosed C282Y homozygotes underwent a liver biopsy because of SF >1000 µg/L and/or increased transaminases according to current guidelines, with concomitant TE. All of them had clinical and biological evaluation, including HA measurement in 52 cases. RESULTS: A total of 19.5% of patients had F3-F4 severe fibrosis. HA was higher in patients with severe fibrosis, but did not accurately predict severe fibrosis. TE was significantly higher in patients with severe fibrosis (17.2 vs. 4.9 kPa; P < 0.05) and was able to accurately predict fibrosis stage in 47/61 (77%) patients with valid measurement using a lower threshold of 6.4 kPa and an upper threshold of 13.9 kPa. Efficient assessment of severe fibrosis was not possible in patients with intermediate TE values. CONCLUSION: An algorithm that successively employed SF and TE can accurately classify severe fibrosis in 61% of patients, restricting the need for liver biopsy to the 39% of patients with intermediate or unvalid TE values. This algorithm should be validated in independent cohorts before extended use.

A robust collagen scoring method for human liver fibrosis by second harmonic microscopy.

Second Harmonic Generation (SHG) microscopy offers the opportunity to image collagen of type I without staining. We recently showed that a simple scoring method, based on SHG images of histological human liver biopsies, correlates well with the Metavir assessment of fibrosis level (Gailhouste et al., J. Hepatol., 2010). In this article, we present a detailed study of this new scoring method with two different objective lenses. By using measurements of the objectives point spread functions and of the photomultiplier gain, and a simple model of the SHG intensity, we show that our scoring method, applied to human liver biopsies, is robust to the objective's numerical aperture (NA) for low NA, the choice of the reference sample and laser power, and the spatial sampling rate. The simplicity and robustness of our collagen scoring method may open new opportunities in the quantification of collagen content in different organs, which is of main importance in providing diagnostic information and evaluation of therapeutic efficiency.

Fibrillar collagen scoring by second harmonic microscopy: a new tool in the assessment of liver fibrosis.

BACKGROUND & AIMS: Imaging of supramolecular structures by multiphoton microscopy offers significant advantages for studying specific fibrillar compounds in biological tissues. In this study, we aimed to demonstrate the relevance of Second Harmonic Generation (SHG) for assessing and quantifying, without staining, fibrillar collagen in liver fibrosis. METHODS: We first showed the relationship between SHG signal and collagen forms over-produced and accumulated during fibrosis progression. Taking this property into consideration, we developed an innovative method to precisely quantify the fibrosis area in histological slices by scoring of fibrillar collagen deposits (Fibrosis-SHG index). RESULTS: The scoring method was routinely applied to 119 biopsies from patients with chronic liver disease allowing a fast and accurate measurement of fibrosis correlated with the Fibrosis-Metavir score (rho=0.75, p<0.0001). The technique allowed discriminating patients with advanced (moderate to severe) fibrosis (AUROC=0.88, p<0.0001) and cirrhosis (AUROC=0.89, p<0.0001). Taking advantage of its continuous gradation, the Fibrosis-SHG index also allowed the discrimination of several levels of fibrosis within the same F-Metavir stage. The SHG process presented several advantages such as a high reliability and sensitivity that lead to a standardized evaluation of hepatic fibrosis in liver biopsies without staining and pathological examination. CONCLUSIONS: Second harmonic microscopy emerges as an original and powerful tool in the assessment of liver fibrosis and offers new possibilities for the evaluation of experimental protocols. We expect that this technology could easily be applicable in the study of other fibro-proliferative pathologies.

Visualizing chromosomes as transcriptome correlation maps: evidence of chromosomal domains containing co-expressed genes--a study of 130 invasive ductal breast carcinomas.

Completion of the working draft of the human genome has made it possible to analyze the expression of genes according to their position on the chromosomes. Here, we used a transcriptome data analysis approach involving for each gene the calculation of the correlation between its expression profile and those of its neighbors. We used the U133 Affymetrix transcriptome data set for a series of 130 invasive ductal breast carcinomas to construct chromosomal maps of gene expression correlation (transcriptome correlation map). This highlighted nonrandom clusters of genes along the genome with correlated expression in tumors. Some of the gene clusters identified by this method probably arose because of genetic alterations, as most of the chromosomes with the highest percentage of correlated genes (1q, 8p, 8q, 16p, 16q, 17q, and 20q) were also the most frequent sites of genomic alterations in breast cancer. Our analysis showed that several known breast tumor amplicons (at 8p11-p12, 11q13, and 17q12) are located within clusters of genes with correlated expression. Using hierarchical clustering on samples and a Treeview representation of whole chromosome arms, we observed a higher-order organization of correlated genes, sometimes involving very large chromosomal domains that could extend to a whole chromosome arm. Transcription correlation maps are a new way of visualizing transcriptome data. They will help to identify new genes involved in tumor progression and new mechanisms of gene regulation in tumors.