Age-related Ultrastructural Changes Research Articles

Age-related ultrastructural changes in spheroids of the adipose-derived multipotent mesenchymal stromal cells from ovariectomized mice.

Introduction: Adipose-derived multipotent mesenchymal stromal cells (ADSCs) are widely used for cell therapy, in particular for the treatment of diseases of the nervous system. An important issue is to predict the effectiveness and safety of such cell transplants, considering disorders of adipose tissue under age-related dysfunction of sex hormones production. The study aimed to investigate the ultrastructural characteristics of 3D spheroids formed by ADSCs of ovariectomized mice of different ages compared to age-matched controls. Methods: ADSCs were obtained from female CBA/Ca mice randomly divided into four groups: CtrlY-control young (2 months) mice, CtrlO-control old (14 months) mice, OVxY-ovariectomized young mice, and OVxO-ovariectomized old mice of the same age. 3D spheroids were formed by micromass technique for 12-14 days and their ultrastructural characteristics were estimated by transmission electron microscopy. Results and Discussion: The electron microscopy analysis of spheroids from CtrlY animals revealed that ADSCs formed a culture of more or less homogeneous in size multicellular structures. The cytoplasm of these ADSCs had a granular appearance due to being rich in free ribosomes and polysomes, indicating active protein synthesis. Extended electron-dense mitochondria with a regular cristae structure and a predominant condensed matrix were observed in ADSCs from CtrlY group, which could indicate high respiratory activity. At the same time, ADSCs from CtrlO group formed a culture of heterogeneous in size spheroids. In ADSCs from CtrlO group, the mitochondrial population was heterogeneous, a significant part was represented by more round structures. This may indicate an increase in mitochondrial fission and/or an impairment of the fusion. Significantly fewer polysomes were observed in the cytoplasm of ADSCs from CtrlO group, indicating low protein synthetic activity. The cytoplasm of ADSCs in spheroids from old mice had significantly increased amounts of lipid droplets compared to cells obtained from young animals. Also, an increase in the number of lipid droplets in the cytoplasm of ADSCs was observed in both the group of young and old ovariectomized mice compared with control animals of the same age. Together, our data indicate the negative impact of aging on the ultrastructural characteristics of 3D spheroids formed by ADSCs. Our findings are particularly promising in the context of potential therapeutic applications of ADSCs for the treatment of diseases of the nervous system.

Age-related ultrastructural changes in the lateral cortex of the inferior colliculus

Temporal precision, a key component of sound and speech processing in the inferior colliculus (IC), depends on a balance of inhibition and excitation, and this balance degrades during aging. The cause of disrupted excitatory-inhibitory balance in aging is unknown, however changes at the synapse are a likely candidate. We sought to determine whether synaptic changes occur in the lateral cortex of the IC (IClc), a multimodal nucleus that processes lemniscal, intrinsic, somatosensory, and descending auditory input. Using electron microscopic techniques across young, middle age and old Fisher Brown Norway rats, our results demonstrate minimal loss of synapses in middle age, but significant (∼28%) loss during old age. However, in middle age, targeting of GABAergic dendrites by GABAergic synapses is increased and the active zones of excitatory synapses (that predominantly target GABA-negative dendrites) are lengthened. These synaptic changes likely result in a net increase of excitation in the IClc during middle age. Thus, disruption of excitatory-inhibitory balance in the aging IClc may be due to synaptic changes that begin in middle age.

Morphology and age-related changes in calcospherites of human teeth: an ultrastructural study

Background: Dentine has been examined extensively for age-related physiological changes, but there are limited data on age-related changes at ultrastructural level of dentine.Aim: The present study aimed to examine age-related ultrastructural changes in calcospherites of human dentine under the scanning electron microscope.Materials and methods: Thirty single rooted teeth of North Western adult Indians (18–75 years) were collected from the Department of Oral Health Sciences, PGIMER, Chandigarh. Labiolingual sections were prepared and morphology of calcospherites was studied at different locations (coronal, cervical, midroot and apical) of the tooth.Results: Morphologically, four types (I [small, unfused and discrete], II [partially fused and globular], III [large, completely fused] and IV [structureless]) of calcospherites were seen in the sample. With advancing age, type I calcospherites approached neighbouring crystals and changed their form to type II, which ultimately coalesced and transformed to type III. Results revealed that among different age groups (young, middle and old), calcospherites of only type I, II and III showed statistically significant differences in their shapes using Pearson’s Chi-square test. Statistically non-significant differences were obtained in the shapes at different locations of the tooth.Conclusions: Results showed that calcospherites get fused as age advances. There is a change in the shape of calcospherites based on the location of the tooth.

Age-Related Changes in Ultrastructure of Mitochondria. Effect of SkQ1.

For many years, investigators have attempted to identify unique ultrastructural conditions of mitochondria related to aging. However, this did not result in definitive results. At present, this issue has again become of topical interest due to development of the mitochondrial theory of aging and of engineering of a novel antioxidant class known as mitochondria-targeted antioxidants. The review briefly discusses experimental results that, from our perspective, allow the most objective understanding regarding age-related changes in mitochondrial ultrastructure.

Ginger and alpha lipoic acid ameliorate age-related ultrastructural changes in rat liver

Because of the important role that oxidative stress is thought to play in the aging process, antioxidants could be candidates for preventing its related pathologies. We investigated the ameliorative effects of two antioxidant supplements, ginger and alpha lipoic acid (ALA), on hepatic ultrastructural alterations in old rats. Livers of young (4 months) and old (24 months) Wistar rats were studied using transmission electron microscopy. Livers of old rats showed sinusoidal collapse and congestion, endothelial thickening and defenestration, and inconsistent perisinusoidal extracellular matrix deposition. Aged hepatocytes were characterized by hypertrophy, cytoplasmic vacuolization and a significant increase in the volume densities of the nuclei, mitochondria and dense bodies. Lipofuscin accumulation and decreased microvilli in bile canaliculi and space of Disse also were observed. The adverse alterations were ameliorated significantly by both ginger and ALA supplementation; ALA was more effective than ginger. Ginger and ALA appear to be promising anti-aging agents based on their amelioration of ultrastructural alterations in livers of old rats.

Ageing causes Severe Ultra-Structural Modification of Calcium Release Units and Mitochondria in Cardiomyocytes

Ageing is associated to a dramatic increase in the incidence of heart failure, even if the existence of a real age-related cardiomyopathy remains controversial. In this study we performed a morphological study of cardiac cells in hearts from adult and old mice (4 and ≥ 24 months respectively) using confocal and electron microscopy. Our results indicates that the cross sectional areas (CSA) of cardiomyocytes is on the average increased in old hearts (adults: 191±105 μm2; old: 232 ± 147 μm2), with a greater variability in size indicating also the presence of several atrophic cells. The increased CSA may be the result of an increased presence of amorphic (apparently empty) cytoplasmic space between myofibrils (adults: 2.2 ± 3.1; old: 9.7 ± 5.7).As effective contraction and relaxation of cardiomyocytes also depends on Ca2+ supply to myofibrils (handled by calcium release units (CRUs) and sarcoplasmic reticulum (SR) and on efficient ATP production (provided by mitochondria), we have also analyzed in detail these intracellular organelles. The analysis of CRUs indicates that SR/transverse-tubules (TT) couplons become shorter with age and that the number of CRUs/50 μm2 is decreased of about 24% (adults: 5.1±3.3; old: 3.9±2.6). Also mitochondria present structural modifications, with a significant increase in the percentage of organelles presenting severe alterations (3.5% vs. 16.5%, respectively in adult vs. old). Importantly, both CRUs and mitochondria undergo a spatial re-organization with respect to sarcomeres/myofibrils: CRUs are may be miss-oriented (longitudinal) or miss-placed (found at the A band instead of being correctly placed in proximity of Z-lines), while mitochondria are often grouped in an abnormal fashion.These age-related ultra-structural changes may underlie an inefficient supply of Ca2+ and ATP to contractile elements, providing a possible structural explanation for heart dysfunction.

Age-related ultrastructural changes in hypocretinergic terminals in the brainstem and spinal cord of cats

In a previous study, we noted the presence of enlarged “spot-like” structures that are immunoreactive to hypocretin in specific regions of brainstem of aged cats; similar structures were not seen in the same regions of adult cats. In the present study, electron microscopy was combined with hypocretin immunohistochemistry to examine the ultrastructure of these enlarged “spot-like” structures, which were found to consist of enlarged axonal terminals. The terminals were comprised of a large pale core with a dark peripheral rim. Many granules were present within the core; most of these granular structures were not immunostained. On the other hand, the rim contained a high density of hypocretin immunoreactivity; in this peripheral region, large dense-core vesicles and small synaptic vesicles without dense cores were observed. In addition, mitochondria in the peripheral rim region exhibited high electron density, which is indicative of the presence of age-related degenerative changes. Synaptic contacts were observed between the enlarged terminals and adjacent dendrites. Most of these synapses were asymmetric (Gray type I), although a few of them were symmetric (Gray type II). These data suggest that hypocretin transmission is altered during aging, which would be expected to result in age-related changes in the functioning of the hypocretinergic system.

Heterogeneity of growth hormone (GH)-producing cells in aging male rats: ultrastructure and GH gene expression in somatotrope subpopulations

Mammalian aging is characterized by a decline in the content and release of pituitary growth hormone (GH). However, few studies on the age-related changes in the population of GH-producing cells (somatotropes) have been carried out. We have investigated whether changes in number, ultrastructure and GH gene expression in subpopulations of somatotropes could explain the reduced GH release in aged rats. Three representative ages were studied: adult (5-month-old), old (19-month-old), and senescent (26-month-old) male rats. The total number of immunoreactive-GH cells per pituitary gland remained invariable to age. The separation of dispersed pituitary cells on a density gradient yielded two somatotrope subpopulations, of low density (LD) and high density (HD). Both subpopulations were equally represented in adults, whereas in old and senescent rats a predominance of LD-somatotropes was observed. Morphometric analysis showed that subpopulations exhibited storage and biosynthetic features inversely related. In LD-somatotropes, rough endoplasmic reticulum (RER) was more prominent but secretory granules (SG) were less abundant than in HD somatotropes. Concurrently, in situ hybridization for GH mRNA showed that GH gene expression was higher in LD-cells. Differences between subpopulations were essentially retained through the animals' lifespan, but small-sized SG, reduced RER, and low GH mRNA levels were inherent to aging both in LD- and in HD-somatotropes. The present findings demonstrate that the reduced content of pituitary GH in aged male rats is not due to a diminished number of GH-producing cells, but to the numerical predominance of scarcely granulated LD-somatotropes, combined with the decline in GH biosynthetic capacity observed in both subpopulations. In addition, age-related changes in ultrastructure and GH gene expression suggest a chronic inhibition of GH release and/or a weak stimulation of GH biosynthesis affecting both subpopulations.

Changes in the Aging Rat Retina

To characterize aging as a factor responsible for structural changes, the retinae of 47 Wistar-derived albino rats and 50 pigmented rats of the Norway and BDE (Han) strains between the ages of 1 and 36 months were examined by light and electron microscopy and analyzed for changes in cell densities. In all 3 rats strains there was an overall decline in nuclear densities of outer layer nuclei by 38-50% and inner layer nuclei by 27-33% between the ages of 1 and 27 months. Over the same age range, the ganglion cell loss was comparable to the decline in the inner nuclear layer. Neuronal cell death occurred at all ages and was more pronounced in albino rats. Moreover, in albino rats, cones were more resistant than rods to destruction by age and ambient light. As age-related ultrastructural changes in the retinal pigment epithelium (RPE) (1) a substantial accumulation of lipofuscin; (2) an apparent thickening of the basement membrane; (3) greatly enlarged and pleomorphic basal infoldings, and (4) shorter apical microvilli were encountered. Besides mature stage IV melanosomes 27-month-old BDE (Han) and 36-month-old Norway rats also revealed stage III melanosomes. Tyrosinase activity in peripheral RPE cells could be demonstrated in Norway rats up to 12 months old and BDE (Han) rats up to 24 months old. Characteristics of RPE cells in old rats of these two pigmented strains were also melanolysosomes, melanophagolysosomes and melanolipofuscin granules. Age-related changes in retinal vessels were found in the superficial and deep capillary network and consisted of a 2- to 3-fold increase in thickness of the capillary basement membrane.

Ultrastructure of the dorsal skins of hairless descendants derived from Mexican hairless dogs.

Ultrastructural characteristics of the dorsal skin of hairless descendants derived from Mexican hairless dogs (3-month-, 1-year- and 5-year-old) were investigated and compared with those of age-matched beagles. Except that beagles had no melanocytes in epidermis, there was no essential difference in ultrastructural characteristics of epidermis between hairless dogs and beagles. In the Stratum basale of epidermis of hairless dogs, a small number of melanocytes and a few Langerhans cell (LC)-like cells were observed among keratinocytes. Melanocytes contained many melanosomes and a few premelanosomes. LC-like cells were characterized by electron-lucent cytoplasm and lobulated nucleus and lacked melanin granules, tonofilaments and desmosomal attachments. Unlike LC in humans and rodents, these LC-like cells did not contain Birbeck granules. Although age-related ultrastructural changes of dorsal skin were generally not clear both in hairless dogs and in beagles, cells containing melanin granules were not infrequently observed among dermal collagen bundles in 5-year-old hairless dogs.

Skin changes in menopause

Skin signs and symptoms were examined in 46 menopausal women prior to estrogen replacement therapy. Several symptoms such as pruritus, bruising, dryness and thinning were seen more frequently in sun-exposed skin emphasizing the contribution of photoaging. At the end of a 6-mth treatment period, no significant difference was observed in the prevalance or severity of the cutaneous signs and symptoms when patients receiving transdermal 17β-estradiol (Estraderm) were compared with controls (the only exception was cutaneous flushing). Elastic fibers from sun-protected (buttock) skin of menopausal women were studied by light and electron microscopy. In 3 women (ages 30–37) with a history of premature menopause, the elastic fibers had several degenerative changes including coalescence of cystic spaces into lacunae, peripheral fragmentation, granular degeneration and splitting of the fibers into strands. Similar age-related ultrastructural changes are normally found in individuals that are at least 20 yrs older than these patients. These findings are suggestive of a relationship between premature aging of the dermal elastic fibers and estrogen deprivation.

Age-related changes in ultrastructure and chemical composition associated with changes in heat resistance of Neosartorya fischeri ascospores

Ascospores (10 5 /ml) of Neosartorya fischeri var. glaber (FRR 1833) harvested from grape juice agar after 11 d of incubation at 30°C were inactivated by treatment at 82° for 60 min; 25-day-old ascospores survived this heat treatment. To determine if differences in ultrastructure and chemical composition might be related to differences in heat-resistance, ultrastructure as well as protein, lipid, sugar and polyol contents of 11-day-old (heatsensitive) and 25-day-old (heat resistant) ascospores were compared. SEM revealed little difference in external appearance, whereas TEM revealed some internal differences between 11- and 25-day-old ascospores, particularly in the region of germ-tube initiation. Significant qualitative differences in protein content between heat-sensitive and heat-resistant ascospores were observed. The lipid and fatty acid compositions of the two types of ascospore were similar. Heat-resistant ascospores contained higher levels of glycerol, mannitol and trehalose than heat-sensitive ascospores, suggesting that the lowering of internal water activity or membrane stabilization may partially account for increased heat resistance.

An ultrastructural change in developing rat cerebral cortex: a morphometrical study.

Five age groups, each composed of four animals from each of the following ages, were used to assess age-related ultrastructural changes with development in the neuropil of the III layer of the frontal cortex (area 6) in rats; 1, 2, 3, 5 and 12 weeks old. Random samplings within the neuropil were taken to produce 25 electron micrographs in each rat (totaling 500). The profiles of axon terminals, dendrites and mitochondria in each element in the neuropil of each micrograph were traced. The percentage of their areas for the area of neuropil (relative volume fraction) was examined using the image analyzer system. The size and number of synaptic terminals were counted. The relative volume fractions of both the axon terminals and mitochondria in the terminals for the neuropil were found to have increased in the mature rats. On the other hand, the relative volume fraction of dendrites for the neuropil had been unchanged and the size of the terminals had gradually decreased. The number of terminals had progressively increased with development.

Age-related ultrastructural changes in human embryonic lung fibroblasts

Scanning and transmission electron microscopy were used to examine human embryonic lung fibroblasts at different population doubling levels. Scanning electron microscopy of cells at population doubling levels 26, 45 and 59 did not reveal a significant change in cell size with increasing age. However, transmission electron microscopy of cells at population doubling levels 19 and 45 showed an increase in nuclear lobes, a decrease in the number of ribosomes associated with rough endoplasmic reticulum, and changes to the internal structure of mitochondria on increasing population doubling level. No other previously reported age-related changes were found.

Age-related changes in the neuropil in the rat inferior olive nucleus: A quantitative electron microscopic study

Age-related ultrastructural changes in the neuropil in the rat inferior olive nucleus were examined at 3, 6, 12, 18, 24 and 30 months old. The profiles of axon terminals, dendrites and astroglial processes from random samplings within the neuropil were traced. Subsequently, the percentages of these profiled areas in relation to the area of neuropil (relative volume fraction) were examined using the image analyzer system. The relative volume fractions of both axon terminals and dendrites in relation to the neuropil were found to have decreased in the aged rats, while the relative volume fraction of astroglial processes had progressively increased with aging.

Aging in the neuropil of cerebral cortex--a quantitative ultrastructural study.

Six age groups, each composed of four animals from each of the following ages, were used to assess age-related ultrastructural changes in the neuropil of the III layer of the frontal cortex in rats: 3, 6, 12, 18, 24 and 30 months old. Random samplings within the neuropil were taken to produce 40 electron micrographs in each rat (totaling 960). The profiles of axon terminals, dendrites and astroglial processes in the neuropil of each micrograph were traced. Then the percentage of their areas for the area of neuropil (relative volume fraction) was examined using the image analyzer system. The relative volume fractions of both the axon terminals and dendrites for the neuropil were found to have decreased in the aged rats. On the contrary, the relative volume fraction of astroglial processes for the neuropil had progressively increased with aging.

Age dependent ultrastructural changes in different organs of the mecopteran fly Panorpa vulgaris

1. 1. Age related ultrastructural changes in flight muscle, fat body, malpighian tubules, salivary glands, and optic lobes of male mecopteran flies Panorpa vulgaris were studied. 2. 2. In all these organs striking degenerative changes arise with increasing age. Flight muscle degeneration is characterized by myofibril dissolution, deformed and “whorl-like” mitochondria and an extensive hypertrophy of sarcoplasmic reticulum which cover the whole muscle in 13-week old adults. In fat body of aged adults a fatty “cirrhotic degeneration” takes place and a change in fatty acid composition of lipids is assumed. Malpighian tubules in 91-day old individuals show abundant inclusions of the myeloid-type and renal stone-like spheric residual bodies. The mitochondria completely disappeared from the brush border and exhibit different stages of degeneration. The salivary glands of old males lack the protein granules lying in the lumen of the young glands. In the optic lobes (neuropile area) glial and neuronal cytoplasm become reduced with advanced age. Scattered autophagic vacuoles and residual bodies are also present. In contrast, no changes in the optic apparatus itself could be detected. 3. 3. The results were compared with those of Phormia terrae novae, where no such degenerative changes occur.

Age-related ultrastructural changes in the flight muscle of the mosquito, Culex tarsalis

The flight muscle of Culex tarsalis and other Diptera is asynchronous fibrillar muscle. Ultrastructurally, we found that it resembles flight muscle described in other insects, except that it contains more glycogen than has been reported for other species. Profound ultrastructural changes occur in relation to age. Newly emerged mosquitoes have fewer glycogen deposits than older individuals. Glycogen in the young mosquito is in the form of beta particles, 25 nm in diameter, and flight muscle mitochondria of newly emerged individuals are smaller and have fewer cristae than those in older mosquitoes. Three-day-old mosquitoes (the age of all mosquitoes is expressed in days after eclosion) exhibit an abundance of glycogen, some of which exists as a dense aggregation along the M-line (intrafibrillar glycogen). Mitochondria in 3-day-old mosquitoes (i.e. 3 days after eclosion) are more dense than in newly emerged individuals, and about twice as large. In mosquitoes aged 42 days, intrafibrillar glycogen still exists as beta particles, but extrafibrillar glycogen is primarily of the alpha or rosette type. Mitochondria in individuals of this age group are present in two morphological forms. Most are similar in morphology to mitochondria of 3-day-old mosquitoes. A few, however, exhibit fewer cristae, some of which may be tubular, and a less dense matrix. Most glycogen has disappeared from both the intrafibrillar and extrafibrillar locations, in 84-day-old (after eclosion) mosquitoes. Mitochondria are present in two morphological types, as they were in insects, 42 days after eclosion.

Ultrastructural changes accompanying the aging of human diploid cells in culture

The ultrastructure of human diploid fibroblasts, strain WI-38, was studied at several different passage levels, ranging from young (15th passage) to old (56th passage) cells. A number of age-related ultrastructural changes were observed and quantitatively expressed. No statistically significant change in mitochondrial number was observed in these cells as they aged. However, the proportion of mitochondria with completely transverse cristae decreases with the age of the cells. The number of lysosomes and autophagic vacuoles increases significantly in old cells. Old cells are also characterized by prominent and active Golgi-vacuolar apparati, highly lobed nuclei, and more cytoplasmic microfibrils than in young cells. The endoplasmic reticulum of young cells tends to be dilated and filled, whereas in old cells it tends to be constricted and “empty”. Our data lend support to the aging theory, in which congestive engorgement of lysosomes plays an important role.

Age-related changes in ultrastructure and histochemistry of rotiferan organs

Age-related ultrastructural and histochemical changes of the vitellarium, stomach, and dorsal gastric gland were studied in the rotifer Philodina acuticornis odiosa Milne. Changes in all organs were quantitative, rather than qualitative, alterations of organelle populations. The appearance of age pigment or membranous elements and ultrastructural changes of mitochondria were not observed. The most significant changes were increases in the number of inclusion bodies and free ribosomes, of which the latter was not quantitated. Inclusion bodies increased approximately 30-fold in the gastric gland and vitellarium, and approximately 2-fold in the stomach. The histochemical studies showed an age-related increase in acid phosphatase activity in the three organs which was generally well correlated with the increase in inclusion bodies, while there was no age-related increase in lipid content. Results are discussed in relation to current investigations of aging.