Lipofuscin, lipofuscin-like pigments and autofluorescence

Guardo, Giovanni Di

doi:10.4081/ejh.2015.2485

Cited by 60 publications

(53 citation statements)

References 21 publications

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“…The emission of lipofuscins and lipofuscin‐like lipopigments may overlay the AF of flavins. However, while flavins show a well‐defined spectral shape, lipofuscin emission varies under different excitation wavelengths, which helps to authenticate the AF signal detected …”

Section: Endogenous Fluorophoresmentioning

confidence: 99%

“…58 The latter includes bile proteins and biliary acids responsible for a blue AF band, causing changes in overall bile AF that reflect bile composition and provide diagnostic information on liver functionality (Supplemental varies under different excitation wavelengths, which helps to authenticate the AF signal detected. [79][80][81][82][83] Proteins are commonly classified as membrane, globular and structural. Aromatic amino acids, tryptophan, tyrosine and phenylalanine are mostly responsible for the AF in the near-UV region of globular proteins, usually of negligible importance in optical biopsy as compared with structural ones.…”

Section: Endog Enous Fluorophore Smentioning

confidence: 99%

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Autofluorescence‐based optical biopsy: An effective diagnostic tool in hepatology

Croce

Ferrigno

Bottiroli

et al. 2018

Liver International

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Autofluorescence emission of liver tissue depends on the presence of endogenous biomolecules able to fluoresce under suitable light excitation. Overall autofluorescence emission contains much information of diagnostic value because it is the sum of individual autofluorescence contributions from fluorophores involved in metabolism, for example, NAD(P)H, flavins, lipofuscins, retinoids, porphyrins, bilirubin and lipids, or in structural architecture, for example, fibrous proteins, in close relationship with normal, altered or diseased conditions of the liver. Since the 1950s, hepatocytes and liver have been historical models to study NAD(P)H and flavins as in situ, real-time autofluorescence biomarkers of energy metabolism and redox state. Later investigations designed to monitor organ responses to ischaemia/reperfusion were able to predict the risk of dysfunction in surgery and transplantation or support the development of procedures to ameliorate the liver outcome. Subsequently, fluorescent fatty acids, lipofuscin-like lipopigments and collagen were characterized as optical biomarkers of liver steatosis, oxidative stress damage, fibrosis and disease progression. Currently, serum AF is being investigated to improve non-invasive optical diagnosis of liver disease. Validation of endogenous fluorophores and in situ discrimination of cancerous from non-cancerous tissue belong to the few studies on liver in human subjects. These reports along with other optical techniques and the huge work performed on animal models suggest many optically based applications in hepatology. Optical diagnosis is currently offering beneficial outcomes in clinical fields ranging from the respiratory and gastrointestinal tracts, to dermatology and ophthalmology. Accordingly, this review aims to promote an effective bench to bedside transfer in hepatology.

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Section: Endogenous Fluorophoresmentioning

confidence: 99%

Section: Endog Enous Fluorophore Smentioning

confidence: 99%

Autofluorescence‐based optical biopsy: An effective diagnostic tool in hepatology

Croce

Ferrigno

Bottiroli

et al. 2018

Liver International

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show abstract

“…For example, amplification will increase the signal above background sources such as autofluorescence in tissue samples that can be challenging to remove even with clearing approaches (e.g. lipofuscin 17 ). Thus, bDNA amplification should greatly facilitate imaging of tissues with high autofluorescence background.…”

Section: Discussionmentioning

confidence: 99%

“…Finally, although a customized clearing approach has been reported for MERFISH 15 , residual autofluorescence, light scattering, and autofluorescent granules that are difficult to remove (e.g. lipofuscin 17 ) can produce signals that challenge the imaging of single RNA molecules in some samples.…”

Section: Introductionmentioning

confidence: 99%

Multiplexed detection of RNA using MERFISH and branched DNA amplification

Xia

Babcock

Moffitt

et al. 2018

Preprint

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Multiplexed error-robust fluorescence in situ hybridization (MERFISH) allows simultaneous imaging of numerous RNA species in their native cellular environment and hence spatially resolved single-cell transcriptomic measurements. However, the relatively modest brightness of signals from single RNA molecules can become limiting in a number of important applications, such as increasing the imaging throughput, imaging shorter RNAs, and imaging samples with high degrees of background, such as some tissue samples. Here, we introduce a branched DNA (bDNA) amplification approach for MERFISH measurements. This approach produces a drastic signal increase in RNA FISH samples without increasing the fluorescent spot size for individual RNAs or increasing the variation in brightness from spot to spot. Using this approach in combination with MERFISH, we demonstrated RNA imaging and profiling with a near 100% detection efficiency. We further demonstrated that signal amplification improves MERFISH performance when fewer FISH probes are used for each RNA species, which should allow shorter RNAs to be imaged. We anticipate that the combination of bDNA amplification with MERFISH should facilitate many other applications and extend the range of biological questions that can be addressed by this technique in both cell culture and tissues.

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“…Some of them were intended to improve fixation, embedding and antigen-retrieval procedures for protein immunodetection, with an obvious interest for the techniques suitable for aldehyde-fixed/paraffin-embedded samples, [82][83][84][85][86] which allows to extend the use of histochemical reactions to archived samples. A group of papers [90][91][92][93] were focused on the acquisition and interpretation of autofluorescence spectra from unprocessed biological tissues in vivo and ex vivo. In fact, under appropriate light excitation several molecular components (such as collagen and elastin, porphyrin derivatives, fatty acids, vitamin A, lipofuscins, NAD(P)H and flavins) act as endogenous fluorophores emitting in the UV-visible to near-IR spectral range, and may be used as intrinsic biomarkers to monitor the biological substrate conditions.…”

Section: Histochemistry Of Single Moleculesmentioning

confidence: 99%

Histochemistry today: Detection and location of single molecules

Pellicciari¹

2017

Eur J Histochem

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Especially in the latest years, histochemical investigations have progressively been oriented toward the visualization and quantitative assessment of single molecules, thanks to the availability of stains, reactions and procedures allowing to detect in situ proteins, or carboydrates or nucleic acid sequences with high specificity. This is evident from the recent literature, where in the large majority of the published articles immunohistochemistry, lectin histochemistry or fluorescence in situ hybridization were used as experimental methodologies. Since in biomedical research it is crucial to specifically label and localize molecules there, where they exert their structural roles and activities, histochemistry will continue to provide scientists the most appropriate tools for tracing molecular maps suitable for reaching a mechanistic explanation of cell functions in tissues.

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Lipofuscin, lipofuscin-like pigments and autofluorescence

Cited by 60 publications

References 21 publications

Autofluorescence‐based optical biopsy: An effective diagnostic tool in hepatology

Autofluorescence‐based optical biopsy: An effective diagnostic tool in hepatology

Multiplexed detection of RNA using MERFISH and branched DNA amplification

Histochemistry today: Detection and location of single molecules

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