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Constantine A Stratakis - One of the best experts on this subject based on the ideXlab platform.
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Lipofuscin accumulation in cortisol producing adenomas with and without prkaca mutations
Hormone and Metabolic Research, 2017Co-Authors: Anna Angelousi, Vincent Shram, Eva Szarek, Electron Kebebew, Martha Quezado, Constantine A StratakisAbstract:The adrenal cortex accumulates Lipofuscin granules with age. Lipofuscin accumulation is also seen in adrenocortical tumors associated with Cushing syndrome (CS), particularly those with PRKAR1A mutations, such as in primary pigmented nodular adrenocortical disease (PPNAD). We investigated the presence of Lipofuscin in cortisol-producing adenomas (CPAs) responsible for CS with and without the PRKACA (pLeu206Arg) somatic mutation. Ten paraffin-embedded sections of CPAs from cases with overt CS with (n=4) and without (n=6) a PRKACA mutation were microscopically examined through three detection methods, the hematoxylin-Eosin (H & E) staining, the Fontana Masson (FM) staining using light microscopy, and Lipofuscin autofluorescence, using confocal laser scanning microscopy (CLSM). Sections were examined quantitatively according to the intensity of the pigmentation, as well as qualitatively based on the total number of granular pigments at all visual fields per tissue slide. Tissues from CPAs were compared to peritumoral adjacent tissues (n=5), to Conn adenomas (n=4), and PPNAD (n=3). CPAs had significantly higher number of Lipofuscin-pigment granules compared to peritumoral adrenal tissue and Conn adenomas (46.9±9.5 vs. 3.8±4.8, p=0.0001). The presence of the PRKACA mutation did not increase the chances of pigmentation in the form of Lipofuscin granules within CPAs associated with CS. Thus, all CPAs leading to CS accumulate Lipofuscin, which presents like pigmentation sometimes seen macroscopically but always detected microscopically. PPNAD caused by PRKAR1A mutations is the best known adrenal lesion leading to CS associated with intense Lipofuscin pigmentation and this was confirmed here; CPAs harboring PRKACA mutations did not have statistically significantly more pigmentation than CPAs without mutation, but a larger study might have shown a difference.
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Lipofuscin accumulation in cortisol producing adenomas with and without prkaca mutations
Hormone and Metabolic Research, 2017Co-Authors: Anna Angelousi, Vincent Shram, Eva Szarek, Electron Kebebew, Martha Quezado, Constantine A StratakisAbstract:The adrenal cortex accumulates Lipofuscin granules with age. Lipofuscin accumulation is also seen in adrenocortical tumors associated with Cushing syndrome (CS), particularly those with PRKAR1A mutations, such as in primary pigmented nodular adrenocortical disease (PPNAD). We investigated the presence of Lipofuscin in cortisol-producing adenomas (CPAs) responsible for CS with and without the PRKACA (pLeu206Arg) somatic mutation. Ten paraffin-embedded sections of CPAs from cases with overt CS with (n=4) and without (n=6) a PRKACA mutation were microscopically examined through three detection methods, the hematoxylin-Eosin (H & E) staining, the Fontana Masson (FM) staining using light microscopy, and Lipofuscin autofluorescence, using confocal laser scanning microscopy (CLSM). Sections were examined quantitatively according to the intensity of the pigmentation, as well as qualitatively based on the total number of granular pigments at all visual fields per tissue slide. Tissues from CPAs were compared to peritumoral adjacent tissues (n=5), to Conn adenomas (n=4), and PPNAD (n=3). CPAs had significantly higher number of Lipofuscin-pigment granules compared to peritumoral adrenal tissue and Conn adenomas (46.9±9.5 vs. 3.8±4.8, p=0.0001). The presence of the PRKACA mutation did not increase the chances of pigmentation in the form of Lipofuscin granules within CPAs associated with CS. Thus, all CPAs leading to CS accumulate Lipofuscin, which presents like pigmentation sometimes seen macroscopically but always detected microscopically. PPNAD caused by PRKAR1A mutations is the best known adrenal lesion leading to CS associated with intense Lipofuscin pigmentation and this was confirmed here; CPAs harboring PRKACA mutations did not have statistically significantly more pigmentation than CPAs without mutation, but a larger study might have shown a difference.
Michael E. Boulton - One of the best experts on this subject based on the ideXlab platform.
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Proteomic and Ultrastructural Analyses of Human Lipofuscin
Investigative Ophthalmology & Visual Science, 2005Co-Authors: Bogdan G. Gugiu, Malgorzata Barbara Rozanowska, Bartosz Rozanowski, Mary E. Rayborn, Vera L. Bonilha, Robert G. Salomon, Joe G. Hollyfield, Michael E. Boulton, John W. CrabbAbstract:Purpose: The progressive accumulation of Lipofuscin in the retinal pigment epithelium (RPE), correlates with the pathogenesis of age-related macular degeneration (AMD). We seek a better molecular understanding of the sources and consequences of Lipofuscin accumulation, including the protein content of Lipofuscin. Methods: Human RPE Lipofuscin was purified by conventional sucrose density gradient centrifugation methods. Lipofuscin granule purity was evaluated by light, fluorescence, confocal, and electron microscopy. Lipofuscin preparations were extracted with chloroform/methanol then the chloroform insoluble material was extracted with SDS and subjected to SDS-PAGE, gel bands excised and proteins identified by LC MS/MS. Western analysis was used to probe for oxidative protein modifications. Results: Ultrastructural analyses of Lipofuscin purified by conventional methods revealed a heterogeneous core structure composed of Lipofuscin granules surrounded by substantial extra-granular material. The chloroform insoluble Lipofuscin fraction of the conventional preparation exhibited many fuzzy Coomassie blue stained SDS-PAGE bands, suggesting post-translational modifications. Western blot analysis confirmed the presence of abundant carboxyethylpyrrole adducts. Over 160 proteins were identified, ~33% of which exhibited apparent mass additions. Essentially “pure” Lipofuscin granules, free of extra-granular material, were obtained by proteolytic digestion of the conventional preparation. Boiling the purified granules in SDS has so far failed to yield SDS-PAGE detectable bands with Coomassie or silver staining. Conclusions: Lipofuscin granules appear to be embedded in a protein “matrix” similar in content to drusen. Proteomic characterization of purified Lipofuscin granules is underway.
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Proteomic and ultrastructural analyses of human Lipofuscin [Abstract]
2005Co-Authors: Bogdan G. Gugiu, Malgorzata Barbara Rozanowska, Bartosz Rozanowski, Mary E. Rayborn, Vera L. Bonilha, Robert G. Salomon, Joe G. Hollyfield, Michael E. Boulton, John W. CrabbAbstract:Purpose: The progressive accumulation of Lipofuscin in the retinal pigment epithelium (RPE), correlates with the pathogenesis of age–related macular degeneration (AMD). We seek a better molecular understanding of the sources and consequences of Lipofuscin accumulation, including the protein content of Lipofuscin. Methods: Human RPE Lipofuscin was purified by conventional sucrose density gradient centrifugation methods. Lipofuscin granule purity was evaluated by light, fluorescence, confocal, and electron microscopy. Lipofuscin preparations were extracted with chloroform/methanol then the chloroform insoluble material was extracted with SDS and subjected to SDS–PAGE, gel bands excised and proteins identified by LC MS/MS. Western analysis was used to probe for oxidative protein modifications. Results: Ultrastructural analyses of Lipofuscin purified by conventional methods revealed a heterogeneous core structure composed of Lipofuscin granules surrounded by substantial extra–granular material. The chloroform insoluble Lipofuscin fraction of the conventional preparation exhibited many fuzzy Coomassie blue stained SDS–PAGE bands, suggesting post–translational modifications. Western blot analysis confirmed the presence of abundant carboxyethylpyrrole adducts. Over 160 proteins were identified, ~33% of which exhibited apparent mass additions. Essentially "pure" Lipofuscin granules, free of extra–granular material, were obtained by proteolytic digestion of the conventional preparation. Boiling the purified granules in SDS has so far failed to yield SDS–PAGE detectable bands with Coomassie or silver staining. Conclusions: Lipofuscin granules appear to be embedded in a protein "matrix" similar in content to drusen. Proteomic characterization of purified Lipofuscin granules is underway.
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age related changes in the photoreactivity of retinal Lipofuscin granules role of chloroform insoluble components
Investigative Ophthalmology & Visual Science, 2004Co-Authors: Malgorzata Barbara Rozanowska, Anna Pawlak, Mariusz Zareba, Tadeusz Sarna, Bartosz Rozanowski, Michael E. Boulton, Christine M B Skumatz, Janice M Burke, John D. SimonAbstract:purpose. Lipofuscin accumulates in human retinal pigment epithelium (RPE) cells with age and may be the main factor responsible for the increasing susceptibility of RPE to photo-oxidation with age. As the composition, absorption, and fluorescence of Lipofuscin undergo age-related changes, the purpose of this study was to determine whether photoreactivity of Lipofuscin granules also changes with the donor age. methods. To determine whether the photoreactivity of Lipofuscin itself is age related, Lipofuscin granules were isolated from human RPE and pooled into age groups. Photoreactivity was assessed by measuring action spectra of photo-induced oxygen uptake and photogeneration of reactive oxygen species. Separation of chloroform-soluble (ChS) and -insoluble (ChNS) components by Folch’s extraction was used to determine the factors responsible for the age-related increase in Lipofuscin photoreactivity. results. The observed rates of photo-induced oxygen uptake and photo-induced accumulation of superoxide-derived spin adducts indicated that when normalized to equal numbers of Lipofuscin granules, aerobic photoreactivity of Lipofuscin increased with age. Both ChS and ChNS mediated photogeneration of singlet oxygen, superoxide radical anion, and photo-oxidation of added lipids and proteins. Although both ChS and ChNS exhibited substantial photoreactivities, neither exhibited significant age-related changes when normalized to equal dry mass. In contrast, ChNS contents in Lipofuscin granules significantly increased with aging. conclusions. Aerobic photoreactivity of RPE Lipofuscin substantially increases with aging. This effect may be ascribed to the increased content of insoluble components.
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inhibition of rpe lysosomal and antioxidant activity by the age pigment Lipofuscin
Investigative Ophthalmology & Visual Science, 2001Co-Authors: Farrukh A Shamsi, Michael E. BoultonAbstract:PURPOSE. To determine whether Lipofuscin is detrimental to lysosomal and antioxidant function in cultured human retinal pigment epithelial (RPE) cells. METHODS. Isolated Lipofuscin granules were fed to confluent RPE cultures and the cells maintained in basal medium for 7 days. Parallel cultures were established that did not receive Lipofuscin. Cultures were either exposed to visible light (390–550 nm) at an irradiance of 2.8 mW/cm2 or maintained in the dark at 37°C for up to 24 hours. Cells were subsequently assessed for cell viability, lysosomal enzyme activity, and antioxidant capacity. RESULTS. There was no loss of cell viability during the first 3 hours of light exposure, whereas a 10% loss of viability was observed in Lipofuscin-fed cultures after 6 hours’ exposure to light. Activities of acid phosphatase, N-acetyl-AŸ-glucuronidase, and cathepsin D were decreased by up to 50% in Lipofuscin-fed cells exposed to light compared with either unfed cells or cells maintained in the dark. There was also a decrease in the antioxidant potential of RPE cells. Catalase and superoxide dismutase activities decreased by up to 60% and glutathione levels by 28% in light-exposed Lipofuscin-fed cells compared with unfed cells or cells maintained in the dark. CONCLUSIONS. Lipofuscin has the capacity to reduce the efficacy of the lysosomal and antioxidant systems in RPE cells that may play an important role in retinal ageing and the development of age-related macular degeneration.
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photocytotoxicity of Lipofuscin in human retinal pigment epithelial cells
Free Radical Biology and Medicine, 2001Co-Authors: Sallyanne Davies, Mariusz Zareba, Tadeusz Sarna, Farrukh A Shamsi, Michael H Elliott, Eric Floor, George T Truscott, Michael E. BoultonAbstract:Lipofuscin accumulates with age in a variety of highly metabolically active cells, including the retinal pigment epithelium (RPE) of the eye, where its photoreactivity has the potential for cellular damage. The aim of this study was to assess the phototoxic potential of Lipofuscin in the retina. RPE cell cultures were fed isolated Lipofuscin granules and maintained in basal medium for 7 d. Control cells lacking granules were cultured in an identical manner. Cultures were either maintained in the dark or exposed to visible light (2.8 mWcm2) at 37 degrees C for up to 48 h. Cells were subsequently assessed for alterations in cell morphology, cell viability, lysosomal stability, lipid peroxidation, and protein oxidation. Exposure of Lipofuscin-fed cells to short wavelength visible light (390-550 nm) caused lipid peroxidation (increased levels of malondialdehyde and 4-hydroxy-nonenal), protein oxidation (protein carbonyl formation), loss of lysosomal integrity, cytoplasmic vacuolation, and membrane blebbing culminating in cell death. This effect was wavelength-dependent because light exposure at 550 to 800 nm had no adverse effect on Lipofuscin-loaded cells. These results confirm the photoxicity of Lipofuscin in a cellular system and implicate it in cell dysfunction such as occurs in ageing and retinal diseases.
Malgorzata Barbara Rozanowska - One of the best experts on this subject based on the ideXlab platform.
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retinal pigment epithelium Lipofuscin proteomics
Molecular & Cellular Proteomics, 2008Co-Authors: Kwokpeng Ng, Bogdan G. Gugiu, Kutralanathan Renganathan, M Davies, Xiaorong Gu, J S Crabb, Malgorzata Barbara RozanowskaAbstract:Lipofuscin accumulates with age in the retinal pigment epithelium (RPE) in discrete granular organelles and may contribute to age-related macular degeneration. Because previous studies suggest that Lipofuscin contains protein that may impact pathogenic mechanisms, we pursued proteomics analysis of Lipofuscin. The composition of RPE Lipofuscin and its mechanisms of pathogenesis are poorly understood in part because of the heterogeneity of isolated preparations. We purified RPE Lipofuscin granules by treatment with proteinase K or SDS and showed by light, confocal, and transmission electron microscopy that the purified granules are free of extragranular material and associated membranes. Crude and purified Lipofuscin preparations were quantitatively compared by (i) LC MS/MS proteomics analyses, (ii) immunoanalyses of oxidative protein modifications, (iii) amino acid analysis, (iv) HPLC of bisretinoids, and (v) assaying phototoxicity to RPE cells. From crude Lipofuscin preparations 186 proteins were identified, many of which appeared to be modified. In contrast, very little protein (∼2% (w/w) by amino acid analysis) and no identifiable protein were found in the purified granules, which retained full phototoxicity to cultured RPE cells. Our analyses showed that granules in purified and crude Lipofuscin preparations exhibit no statistically significant differences in diameter or circularity or in the content of the bisretinoids A2E, isoA2E, and all-trans-retinal dimer-phosphatidylethanolamine. The finding that the purified granules contain minimal protein yet retain phototoxic activity suggests that RPE Lipofuscin pathogenesis is largely independent of associated protein. The purified granules also exhibited oxidative protein modifications, including nitrotyrosine generated from reactive nitrogen oxide species and carboxyethylpyrrole and iso[4]levuglandin E2 adducts generated from reactive lipid fragments. This finding is consistent with previous studies demonstrating RPE Lipofuscin to be a potent generator of reactive oxygen species and supports the hypothesis that such species, including reactive fragments from lipids and retinoids, contribute to the mechanisms of RPE Lipofuscin pathogenesis.
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Proteomic and Ultrastructural Analyses of Human Lipofuscin
Investigative Ophthalmology & Visual Science, 2005Co-Authors: Bogdan G. Gugiu, Malgorzata Barbara Rozanowska, Bartosz Rozanowski, Mary E. Rayborn, Vera L. Bonilha, Robert G. Salomon, Joe G. Hollyfield, Michael E. Boulton, John W. CrabbAbstract:Purpose: The progressive accumulation of Lipofuscin in the retinal pigment epithelium (RPE), correlates with the pathogenesis of age-related macular degeneration (AMD). We seek a better molecular understanding of the sources and consequences of Lipofuscin accumulation, including the protein content of Lipofuscin. Methods: Human RPE Lipofuscin was purified by conventional sucrose density gradient centrifugation methods. Lipofuscin granule purity was evaluated by light, fluorescence, confocal, and electron microscopy. Lipofuscin preparations were extracted with chloroform/methanol then the chloroform insoluble material was extracted with SDS and subjected to SDS-PAGE, gel bands excised and proteins identified by LC MS/MS. Western analysis was used to probe for oxidative protein modifications. Results: Ultrastructural analyses of Lipofuscin purified by conventional methods revealed a heterogeneous core structure composed of Lipofuscin granules surrounded by substantial extra-granular material. The chloroform insoluble Lipofuscin fraction of the conventional preparation exhibited many fuzzy Coomassie blue stained SDS-PAGE bands, suggesting post-translational modifications. Western blot analysis confirmed the presence of abundant carboxyethylpyrrole adducts. Over 160 proteins were identified, ~33% of which exhibited apparent mass additions. Essentially “pure” Lipofuscin granules, free of extra-granular material, were obtained by proteolytic digestion of the conventional preparation. Boiling the purified granules in SDS has so far failed to yield SDS-PAGE detectable bands with Coomassie or silver staining. Conclusions: Lipofuscin granules appear to be embedded in a protein “matrix” similar in content to drusen. Proteomic characterization of purified Lipofuscin granules is underway.
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Proteomic and ultrastructural analyses of human Lipofuscin [Abstract]
2005Co-Authors: Bogdan G. Gugiu, Malgorzata Barbara Rozanowska, Bartosz Rozanowski, Mary E. Rayborn, Vera L. Bonilha, Robert G. Salomon, Joe G. Hollyfield, Michael E. Boulton, John W. CrabbAbstract:Purpose: The progressive accumulation of Lipofuscin in the retinal pigment epithelium (RPE), correlates with the pathogenesis of age–related macular degeneration (AMD). We seek a better molecular understanding of the sources and consequences of Lipofuscin accumulation, including the protein content of Lipofuscin. Methods: Human RPE Lipofuscin was purified by conventional sucrose density gradient centrifugation methods. Lipofuscin granule purity was evaluated by light, fluorescence, confocal, and electron microscopy. Lipofuscin preparations were extracted with chloroform/methanol then the chloroform insoluble material was extracted with SDS and subjected to SDS–PAGE, gel bands excised and proteins identified by LC MS/MS. Western analysis was used to probe for oxidative protein modifications. Results: Ultrastructural analyses of Lipofuscin purified by conventional methods revealed a heterogeneous core structure composed of Lipofuscin granules surrounded by substantial extra–granular material. The chloroform insoluble Lipofuscin fraction of the conventional preparation exhibited many fuzzy Coomassie blue stained SDS–PAGE bands, suggesting post–translational modifications. Western blot analysis confirmed the presence of abundant carboxyethylpyrrole adducts. Over 160 proteins were identified, ~33% of which exhibited apparent mass additions. Essentially "pure" Lipofuscin granules, free of extra–granular material, were obtained by proteolytic digestion of the conventional preparation. Boiling the purified granules in SDS has so far failed to yield SDS–PAGE detectable bands with Coomassie or silver staining. Conclusions: Lipofuscin granules appear to be embedded in a protein "matrix" similar in content to drusen. Proteomic characterization of purified Lipofuscin granules is underway.
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age related changes in the photoreactivity of retinal Lipofuscin granules role of chloroform insoluble components
Investigative Ophthalmology & Visual Science, 2004Co-Authors: Malgorzata Barbara Rozanowska, Anna Pawlak, Mariusz Zareba, Tadeusz Sarna, Bartosz Rozanowski, Michael E. Boulton, Christine M B Skumatz, Janice M Burke, John D. SimonAbstract:purpose. Lipofuscin accumulates in human retinal pigment epithelium (RPE) cells with age and may be the main factor responsible for the increasing susceptibility of RPE to photo-oxidation with age. As the composition, absorption, and fluorescence of Lipofuscin undergo age-related changes, the purpose of this study was to determine whether photoreactivity of Lipofuscin granules also changes with the donor age. methods. To determine whether the photoreactivity of Lipofuscin itself is age related, Lipofuscin granules were isolated from human RPE and pooled into age groups. Photoreactivity was assessed by measuring action spectra of photo-induced oxygen uptake and photogeneration of reactive oxygen species. Separation of chloroform-soluble (ChS) and -insoluble (ChNS) components by Folch’s extraction was used to determine the factors responsible for the age-related increase in Lipofuscin photoreactivity. results. The observed rates of photo-induced oxygen uptake and photo-induced accumulation of superoxide-derived spin adducts indicated that when normalized to equal numbers of Lipofuscin granules, aerobic photoreactivity of Lipofuscin increased with age. Both ChS and ChNS mediated photogeneration of singlet oxygen, superoxide radical anion, and photo-oxidation of added lipids and proteins. Although both ChS and ChNS exhibited substantial photoreactivities, neither exhibited significant age-related changes when normalized to equal dry mass. In contrast, ChNS contents in Lipofuscin granules significantly increased with aging. conclusions. Aerobic photoreactivity of RPE Lipofuscin substantially increases with aging. This effect may be ascribed to the increased content of insoluble components.
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Action spectra for the photoconsumption of oxygen by human ocular Lipofuscin and Lipofuscin extracts.
Archives of Biochemistry and Biophysics, 2002Co-Authors: Anna Pawlak, Malgorzata Barbara Rozanowska, Mariusz Zareba, Laura E. Lamb, John D. Simon, Tadeusz SarnaAbstract:The action spectra for the photoconsumption of oxygen by Lipofuscin isolated from human retinal pigment epithelium cells and liposomal suspensions containing extracts of Lipofuscin are reported. The Lipofuscin and Lipofuscin extract action spectra are similar, demonstrating the phototoxic constituents of Lipofuscin are present in the Lipofuscin solvent extract. 2-[2,6-Dimethyl-8-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1E,3E,5E,7E-octatetraenyl]-1-(2-hydroxyethyl)-4-[4-methyl-6-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1E,3E,5E-hexatrienyl]-pyridinium (A2E), present in both intact granules and the solvent extract, has been invoked as an important contributor to the phototoxicity of Lipofuscin. The action spectrum for oxygen photoconsumption by A2E follows its absorption spectrum but does not resemble the action spectrum for photoconsumption of oxygen by Lipofuscin granules or Lipofuscin extract. These results combined with recently reported experimental studies on the aerobic photoreactivity of A2E indicate that it is not a major contributor to the phototoxicity of Lipofuscin.
Anna Angelousi - One of the best experts on this subject based on the ideXlab platform.
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Lipofuscin accumulation in cortisol producing adenomas with and without prkaca mutations
Hormone and Metabolic Research, 2017Co-Authors: Anna Angelousi, Vincent Shram, Eva Szarek, Electron Kebebew, Martha Quezado, Constantine A StratakisAbstract:The adrenal cortex accumulates Lipofuscin granules with age. Lipofuscin accumulation is also seen in adrenocortical tumors associated with Cushing syndrome (CS), particularly those with PRKAR1A mutations, such as in primary pigmented nodular adrenocortical disease (PPNAD). We investigated the presence of Lipofuscin in cortisol-producing adenomas (CPAs) responsible for CS with and without the PRKACA (pLeu206Arg) somatic mutation. Ten paraffin-embedded sections of CPAs from cases with overt CS with (n=4) and without (n=6) a PRKACA mutation were microscopically examined through three detection methods, the hematoxylin-Eosin (H & E) staining, the Fontana Masson (FM) staining using light microscopy, and Lipofuscin autofluorescence, using confocal laser scanning microscopy (CLSM). Sections were examined quantitatively according to the intensity of the pigmentation, as well as qualitatively based on the total number of granular pigments at all visual fields per tissue slide. Tissues from CPAs were compared to peritumoral adjacent tissues (n=5), to Conn adenomas (n=4), and PPNAD (n=3). CPAs had significantly higher number of Lipofuscin-pigment granules compared to peritumoral adrenal tissue and Conn adenomas (46.9±9.5 vs. 3.8±4.8, p=0.0001). The presence of the PRKACA mutation did not increase the chances of pigmentation in the form of Lipofuscin granules within CPAs associated with CS. Thus, all CPAs leading to CS accumulate Lipofuscin, which presents like pigmentation sometimes seen macroscopically but always detected microscopically. PPNAD caused by PRKAR1A mutations is the best known adrenal lesion leading to CS associated with intense Lipofuscin pigmentation and this was confirmed here; CPAs harboring PRKACA mutations did not have statistically significantly more pigmentation than CPAs without mutation, but a larger study might have shown a difference.
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Lipofuscin accumulation in cortisol producing adenomas with and without prkaca mutations
Hormone and Metabolic Research, 2017Co-Authors: Anna Angelousi, Vincent Shram, Eva Szarek, Electron Kebebew, Martha Quezado, Constantine A StratakisAbstract:The adrenal cortex accumulates Lipofuscin granules with age. Lipofuscin accumulation is also seen in adrenocortical tumors associated with Cushing syndrome (CS), particularly those with PRKAR1A mutations, such as in primary pigmented nodular adrenocortical disease (PPNAD). We investigated the presence of Lipofuscin in cortisol-producing adenomas (CPAs) responsible for CS with and without the PRKACA (pLeu206Arg) somatic mutation. Ten paraffin-embedded sections of CPAs from cases with overt CS with (n=4) and without (n=6) a PRKACA mutation were microscopically examined through three detection methods, the hematoxylin-Eosin (H & E) staining, the Fontana Masson (FM) staining using light microscopy, and Lipofuscin autofluorescence, using confocal laser scanning microscopy (CLSM). Sections were examined quantitatively according to the intensity of the pigmentation, as well as qualitatively based on the total number of granular pigments at all visual fields per tissue slide. Tissues from CPAs were compared to peritumoral adjacent tissues (n=5), to Conn adenomas (n=4), and PPNAD (n=3). CPAs had significantly higher number of Lipofuscin-pigment granules compared to peritumoral adrenal tissue and Conn adenomas (46.9±9.5 vs. 3.8±4.8, p=0.0001). The presence of the PRKACA mutation did not increase the chances of pigmentation in the form of Lipofuscin granules within CPAs associated with CS. Thus, all CPAs leading to CS accumulate Lipofuscin, which presents like pigmentation sometimes seen macroscopically but always detected microscopically. PPNAD caused by PRKAR1A mutations is the best known adrenal lesion leading to CS associated with intense Lipofuscin pigmentation and this was confirmed here; CPAs harboring PRKACA mutations did not have statistically significantly more pigmentation than CPAs without mutation, but a larger study might have shown a difference.
John J. Weiter - One of the best experts on this subject based on the ideXlab platform.
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Lipofuscin and the Principles of Fundus Autofluorescence: A Review
Seminars in Ophthalmology, 2012Co-Authors: Namrata Nandakumar, Sheldon M. Buzney, John J. WeiterAbstract:Fundus autofluorescence is a non-invasive imaging modality that measures Lipofuscin that has accumulated in the retinal pigment epithelium (RPE). Excessive Lipofuscin in the RPE is a common pathway found in several diseases including Stargardt’s disease and age-related macular degeneration. This review discusses the role of photooxidative damage in the development of Lipofuscin and the principles of fundus autofluorescence.
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in vivo measurement of Lipofuscin in stargardt s disease fundus flavimaculatus
Investigative Ophthalmology & Visual Science, 1995Co-Authors: Francois C Delori, Giovanni Staurenghi, O Arend, C K Dorey, D G Goger, John J. WeiterAbstract:PURPOSE: Several histopathologic studies have concluded that Stargardt's disease (Fundus flavimaculatus) is associated with abnormally high levels of Lipofuscin-like material in the retinal pigment epithelium. The purpose of this study was to determine whether this material has the same fluorescence characteristics as Lipofuscin in vivo and whether noninvasive measurements identify a significant elevation in this material. METHODS: Five patients with autosomal recessive Stargardt's disease were included in this study, as were 45 healthy controls. All patients had the angiographic dark choroid sign. The intensity and emission spectra of Lipofuscin fluorescence were measured by noninvasive fundus spectrophotometry at 7 degrees temporal to the fovea. RESULTS: The fluorescence intensities in the five patients with Stargardt's disease were significantly higher (P < 0.0001) than those observed in normal subjects of the same age. The emission spectra in the patients are similar in shape to those measured in normals, but flecks appear to shift the spectra toward shorter wavelengths. CONCLUSIONS: The spectral characteristics of the fluorophore observed in patients with Stargardt's disease are consistent with those of retinal pigment epithelial Lipofuscin. These patients have abnormally high levels of Lipofuscin, confirming previous histopathologic observations. Noninvasive retinal pigment epithelial Lipofuscin measurements may be a useful adjunct in the diagnosis of Stargardt's disease.-F. flavimaculatus.
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in vivo measurement of Lipofuscin in stargardt s disease fundus flavimaculatus
Investigative Ophthalmology & Visual Science, 1995Co-Authors: Francois C Delori, Giovanni Staurenghi, O Arend, C K Dorey, D G Goger, John J. WeiterAbstract:Purpose. Several histopathologic studies have concluded that Stargardt's disease (Fundus flavimaculatus) is associated with abnormally high levels of Lipofuscin-like material in the retinal pigment epithelium. The purpose of this study was to determine whether this material has the same fluorescence characteristics as Lipofuscin in vivo and whether noninvasive measurements identify a significant elevation in this material. Methods. Five patients with autosomal recessive Stargardt's disease were included in this study, as were 45 healthy controls. All patients had the angiographic dark choroid sign. The intensity and emission spectra of Lipofuscin fluorescence were measured by noninvasive fundus spectrophotometry at 7° temporal to the fovea. Results. The fluorescence intensities in the five patients with Stargardt's disease were significantly higher (P < 0.0001) than those observed in normal subjects of the same age. The emission spectra in the patients are similar in shape to those measured in normals, but flecks appear to shift the spectra toward shorter wavelengths. Conclusions. The spectral characteristics of the fluorophore observed in patients with Stargardt's disease are consistent with those of retinal pigment epithelial Lipofuscin. These patients have abnormally high levels of Lipofuscin, confirming previous histopathologic observations. Noninvasive retinal pigment epithelial Lipofuscin measurements may be a useful adjunct in the diagnosis of Stargardt's disease-F. flavimaculatus. Invest Ophthalmol Vis Sci. 1995 ; 36 :2327-2331.