Home  About us  Contact
 

Lipofuscin Accumulation (lipofuscin + accumulation)

Distribution by Scientific Domains
Medical Sciences60%
Life Sciences40%

Selected Abstracts

Ultrastructural changes of posterior lingual glands after hypoglossal denervation in hamsters

JOURNAL OF ANATOMY, Issue 1 2009
S. J. Cheng
Abstract Posterior lingual glands consist of two sets of minor salivary glands that serve important functions in oral physiology. To investigate the hypothesis that the hypoglossal nerve provides sympathetic innervation to the posterior lingual glands, we examined ultrastructural changes in the glands following hypoglossal denervation. In the posterior deep lingual glands (of von Ebner), the serous acinar cells showed a decrease in the number of secretory granules and an increase in lipofuscin accumulation. The ratios of cells containing lipofuscin granules were 11.39, 36.49 and 50.46%, respectively, of the control, 3- and 7-day post-axotomy glands (P < 0.001). Intraepithelial phagocytotic activity was increased. The mucous acinar cells in the posterior superficial lingual glands (of Weber) also showed degenerative changes after hypoglossal denervation. One week after nerve transection, marked cytoplasmic vacuolation and fragmentation of organelles were frequently observed. Degenerative changes were also found in unmyelinated axons associated with the glands. We provide the first evidence of the structural and functional connections between the sympathetic component of the hypoglossal nerve and posterior lingual glands. [source]

Ultrastructure of testicular macrophages in aging mice

JOURNAL OF MORPHOLOGY, Issue 1 2005
Francesco Giannessi
Abstract Testicular macrophages of aging mice were studied by TEM. Testicular macrophages retained with Leydig cells the close morphological relationships observed in the adult young animals, but digitations were not found. Lipofuscin granules like those of the Leydig cells from aging mice were observed in the cytoplasm. These organelles were generally absent in the testicular macrophages of young adult mice. Testicular macrophages did not display phagocytosis of the lipofuscin granules. In addition, the latter were not found in the intercellular spaces. These observations indicated that lipofuscin granules were formed, at least in a great part, within testicular macrophages as a consequence of metabolic changes occurring with age. Fine lamellar organization was seen in the lipofuscin granules of both Leydig cells and testicular macrophages. Frequently, lipofuscin granules originated from secondary lysosomes containing lipidic vacuoles only. Together with accumulation of the lipofuscin granules, changes of testicular macrophage fine morphology were observed. Endoplasmic reticulum and Golgi apparatus became poorly developed, and coated vesicles were rarely found. Fewer mitochondria were encountered, but their ultrastructure was not altered. These results suggest that in testicular macrophages lipofuscin accumulation is associated with a functional involution. J. Morphol. 263:39,46, 2005.© 2004 Wiley-Liss, Inc. [source]

The effect of Polbax extract on lipofuscin accumulation in cultured neonatal rat cardiac myocytes

PHYTOTHERAPY RESEARCH, Issue 2 2002
Alexei Terman
Abstract Polbax®, a water-soluble extract of fresh pollen grains and pistils, was tested for its ability to influence the accumulation of lipofuscin (age pigment) in cultured neonatal rat cardiac myocytes. Exposure for 3 weeks to Polbax at concentrations of 0.1, 1.0 or 10,mg/L decreased lipofuscin accumulation morphometrically assayed using laser scanning microscopy images (green excitation light) of formaldehyde-fixed cells, by 24%, 41% or 43%, respectively. Based on the knowledge that oxidative stress and iron-catalysed peroxidation play an important role in lipofuscinogenesis, we suggest that Polbax may slow lipofuscin formation due to antioxidant activities, perhaps involving intralysosomal dismutation of superoxide produced by autophagocytosed mitochondria and/or iron-chelation. Copyright © 2002 John Wiley & Sons, Ltd. [source]

2231: Age-related modifications in RPE cells

ACTA OPHTHALMOLOGICA, Issue 2010
E MANNERMAA
Age-related macular degeneration (AMD) is a multi-factorial polygenetic aging disease. It has been shown that RPE dysfunction predisposes neural retinal dysfunction and the development of choroidal neovascularization. The pathogenesis of age-related macular degeneration (AMD) essentially involves chronic oxidative stress, increased accumulation of lipofuscin in retinal pigment epithelial (RPE) cells and extracellular drusen formation, as well as the presence of chronic inflammation. The capacity to prevent the accumulation of cellular cytotoxic protein aggregates is decreased in senescent cells which may evoke lipofuscin accumulation into lysosomes in postmitotic RPE cells. This presence of lipofuscin decreases lysosomal enzyme activity and impairs autophagic clearance of damaged proteins which should be removed from cells. Proteasomes are another crucial proteolytic machine which degrades especially cellular proteins damaged by oxidative stress. The cross-talk between lysosomes, autophagy and proteasomes in RPE cell protein aggregation, their role as a possible therapeutic target and their involvement in the pathogenesis of AMD is discussed. In addition, age related changes in Bruch's membrane and choroidal blood flow may take part in the pathogenesis of AMD. This will be also discussed. [source]

New perspectives in retinal imaging: fundus autofluorescence and age-related macular degeneration

ACTA OPHTHALMOLOGICA, Issue 2007
F HOLZ
Fundus Autofluorescence (FAF) imaging using confocal scanning laser ophthalmoscopy is a non-invasive method to to accurately record the topographic distribution of RPE lipofuscin in the human eye in vivo. Excessive lipofuscin accumkulation in the RPE is a common downstream pathogenetic pathway in various complex and monogenetic retinal diseases. Toxic compounds and molecular mechanisms of interference with normal cellular functions have been identified including the dominant fluorophore A2-E. Alterations in fundus autofluorescence (FAF) appearance in eyes with early and late age-related macular degeneration (AMD) can be striking. FAF patterns and distribution do not necessarily correlate with the features of interest in color or angiographic images of eyes with early or late AMD. In the prospective, multicenter FAM study distinct patterns of abnormal FAF were identified and classified in the junctional zone of geographic atrophy (GA). Areas of increased FAF outside GA were associated with variable degrees of loss of retinal sensitivity when tested with microperimetry which suggests a functional correlate of lipofuscin accumulation. Increased FAF preceded the development and enlargement of outer retinal atrophy associated with spread of absolute scotoma in eyes with AMD. Longitudinal examinations showed that the abnormal phenotypic FAF patterns serve as novel prognostic determinants which allows to distinguish fast vs. slow progressors. These findings are relevant and now used to design and carry out interventional trials with agents aimed at slowing down spread of atrophy, e.g. using visual cycle modulators to influence lipofuscinogenesis. Hereby FAF imaging also serves as a mean to accurately delineate and measure areas of GA over time in an automated fashion. A phenotype-genotype correlation was identified for a distinct FAF phenotype subset which was found to represent late-onset Stargardt macular dystrophy mimicking late-stage atrophic AMD. New imaging technologies were recently applied including simultaneous recordings of FAF images and high-resolution, spectral-domain optical coherence tomography (OCT) which allows to identify morphological correlates of abnormal FAF signals in optical biopsies. [source]